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Sample records for aspherical compound lens

  1. Ultra-precision molding of chalcogenide glass aspherical lens

    Science.gov (United States)

    Zhang, Feng; Wang, Zhibin; Zhang, Yunlong; Su, Ying; Guo, Rui; Xu, Zengqi; Liu, Xuanmin

    2016-10-01

    With the development of infrared optical systems in military and civil areas, chalcogenide glass aspherical lens possess some advantages, such as large infrared transmission, good thermal stability performance and image quality. Aspherical lens using chalcogenide glass can satisfy the requirements of modern infrared optical systems. Therefore, precision manufacturing of chalcogenide glass aspheric has received more and more attention. The molding technology of chalcogenide glass aspheric has become a research hotspot, because it can achieve mass and low cost manufacturing. The article of molding technology is focusing on a kind of chalcogenide glass aspherical lens. We report on design and fabrication of the mold that through simulation analysis of molding. Finally, through molding test, the fabrication of mold's surface and parameters of molding has been optimized, ensuring the indicators of chalcogenide glass aspherical lens meet the requirements.

  2. Review of small aspheric glass lens molding technologies

    Science.gov (United States)

    Yin, Shaohui; Jia, Hongpeng; Zhang, Guanhua; Chen, Fengjun; Zhu, Kejun

    2017-01-01

    Aspheric lens can eliminate spherical aberrations, coma, astigmatism, field distortions, and other adverse factors. This type of lens can also reduce the loss of light energy and obtain high-quality images and optical characteristics. The demand for aspheric lens has increased in recent years because of its advantageous use in the electronics industry, particularly for compact, portable devices and high-performance products. As an advanced manufacturing technology, the glass lens molding process has been recognized as a low-cost and high-efficiency manufacturing technology for machining small-diameter aspheric lens for industrial production. However, the residual stress and profile deviation of the glass lens are greatly affected by various key technologies for glass lens molding, including glass and mold-die material forming, mold-die machining, and lens molding. These key technical factors, which affect the quality of the glass lens molding process, are systematically discussed and reviewed to solve the existing technical bottlenecks and problems, as well as to predict the potential applicability of glass lens molding in the future.

  3. The Simulation and Optimization of Aspheric Plastic Lens Injection Molding

    Institute of Scientific and Technical Information of China (English)

    WEN Jialing; WEN Pengfei

    2005-01-01

    For the purpose of reducing the volumetric shrinkage and volumetric shrinkage variation, the process in injection molding of aspheric plastic lens was simulated, and several process parameters which include holding pressure, melt temperature, mold temperature, fill time, holding pressure time and cooling time were optimized by using an orthogonal experimental design method. Finally, the optimum process parameters and the influence degree of process parameters on the average volumetric shrinkage and the volumetric shrinkage variation are obtained.

  4. Clinical study of customized aspherical intraocular lens implants

    Institute of Scientific and Technical Information of China (English)

    Lie-Xi; Jia; Zhao-Hui; Li

    2014-01-01

    AIM:To compare if there is an improvement in visual functions with age-related cataracts between patients receiving a aspherical intraocular lens(IOL) based on corneal wavefront aberration and patients randomly assigned lenses.METHODS:A total of 124 eyes of 124 patients with age-related cataracts were placed in experimental group and a group receiving randomly assigned(RA) lenses.The experimental group was undergone Pentacam corneal spherical aberration measurement before surgery; the targeted range for residual total spherical aberration after surgery was set to 0-0.3 μm. Patients with a corneal spherical aberration <0.3 μm were implanted with a zero-spherical aberration advanced optics(AO) aspherical IOL and patients with an aberration ≥0.3 μm received a Tecnis Z9003 aspherical lens in experimental group. RA patients were randomly implanted with an AO lens or a Tecnis Z9003 lens. Three months after surgery total spherical aberration, photopic/mesopic contrast sensitivities, photopic/mesopic with glare contrast sensitivities, and logMAR vision were measured.RESULTS:Statistical analysis on logMAR vision showed no significant difference between two groups(P =0.413). The post-surgical total spherical aberration was 0.126 ±0.097 μm and 0.152 ±0.151 μm in the experimental and RA groups, respectively(P =0.12). The mesopic contrast sensitivities at spatial frequencies of 6,12 and 18 c/d in the experimental group were significantly higher than of the RA group(P =0.00; P =0.04;P =0.02). The mesopic with glare contrast sensitivity in the experimental group at a spatial frequency of 18 c/d was also significantly higher vs the RA group(P =0.01).CONCLUSION:Pre-surgical corneal spherical aberration measurement in cataract patients followed bycustomized selection of aspherical IOL implants improved mesopic contrast sensitivities at high spatial frequencies, and thus is a superior strategy compared to the random selection of aspherical intraocular lens implants.

  5. Application of Q-type aspheric surface in the design of Wynne-Dyson projection lens

    Science.gov (United States)

    Ho, Cheng-Fang; Peng, Wei-Jei; Hsu, Wei-Yao

    2016-10-01

    ITRC dedicates in high precision optics for more than 40 years and focuses in lithography optics for projection system recently. The first project of the lithography optics in ITRC is an i-line Wynne-Dyson projection lens for 3D-ICs applications. The Wynne-Dyson projection lens is a classical design for unity magnification projection system. We take the advantages of the established benefits of Wynne-Dyson lens and modify it. ITRC`s Wynne-Dyson lens is a 0.16 NA system with unity magnification, which is designed in double telecentricity and long working distance. The projection lens comprises three lenses and one concave mirror. Two aspheric surfaces are deployed in lens 1 and concave mirror. A lens with aspheric surfaces can correct for aberration and deliver a higher performance with fewer lens elements; therefore it has advantages of compact and light. However, aspheres are more difficult to fabricate and higher cost than spherical surface. In order to control the testability and manufacturability of the aspheric surface, the Q-type aspheric surfaces are applied in our design phase and manufacture process. We optimize for both performance and manufacturability by Q-type aspheric surfaces. Not only a testable and manufacturable asphere can be approached but also an additional benefits of less sensitive and cost-effective to manufacture to the required specification. In this paper, the Q-type aspheric surfaces and slope constraint are applied to a Wynne-Dyson projection lens, the testability of Q-type aspheric surfaces by the departure from best-fit-sphere and fringe density of interferometry are estimated. Furthermore, subaperture stitching interferometer system (ASI, from QED technologies) is also applied for testability comparison. The tolerance and sensitivity are also discussed. Finally, the results show a diffraction limit approached lens with testable aspheric surface is designed using Q-type aspheric surface. One of the asphere is 150 m departure from best

  6. Contrast sensitivity after refractive lens exchange with a multifocal diffractive aspheric intraocular lens

    Directory of Open Access Journals (Sweden)

    Teresa Ferrer-Blasco

    2013-04-01

    Full Text Available PURPOSE: To evaluate distance and near contrast sensitivity (CS under photopic and mesopic conditions before and after refractive lens exchange (RLE and implantation of the aspheric AcrySof®ReSTOR® (SN6AD3 model intraocular lens (IOL. METHODS:Seventy-four eyes of 37 patients after RLE underwent bilateral implantation with the aspheric AcrySof ReSTOR IOL. The patient sample was divided into myopic and hyperopic groups. Monocular uncorrected visual acuity at distance and near (UCVA and UCNVA, respectively and monocular best corrected visual acuity at distance and near (BCVA and BCNVA, respectively were measured before and 6 months postoperatively. Monocular CS function was measured at three different luminance levels (85, 5 and 2.5 cd/m² before and after RLE. Post-implantation results at 6 months were compared with those found before surgery. RESULTS: Our results revealed that patients in both groups obtained good UCVA and BCVA after RLE at distance and near vision in relation to pre-surgery values. No statistically significant differences were found between the values of CS pre and post-RLE at distance and near, at any lighting condition and spatial frequency (p>0.002. CONCLUSIONS: Refractive lens exchange with aspheric AcrySof ReSTOR IOL in myopic and hyperopic population provided good visual function and yield good distance and near CS under photopic and mesopic conditions.

  7. Aspherical Lens Design Using Genetic Algorithm for Reducing Aberrations in Multifocal Artificial Intraocular Lens

    Directory of Open Access Journals (Sweden)

    Chih-Ta Yen

    2015-09-01

    Full Text Available A complex intraocular lens (IOL design involving numerous uncertain variables is proposed. We integrated a genetic algorithm (GA with the commercial optical design software of (CODE V to design a multifocal IOL for the human eye. We mainly used an aspherical lens in the initial state to the crystalline type; therefore, we used the internal human eye model in the software. The proposed optimized algorithm employs a GA method for optimally simulating the focusing function of the human eye; in this method, the thickness and curvature of the anterior lens and the posterior part of the IOL were varied. A comparison of the proposed GA-designed IOLs and those designed using a CODE V built-in optimal algorithm for 550 degrees myopia and 175 degrees astigmatism conditions of the human eye for pupil size 6 mm showed that the proposed IOL design improved the spot size of root mean square (RMS, tangential coma (TCO and modulation transfer function (MTF at a spatial frequency of 30 with a pupil size of 6 mm by approximately 17%, 43% and 35%, respectively. However, the worst performance of spherical aberration (SA was lower than 46%, because the optical design involves a tradeoff between all aberrations. Compared with the traditional CODE V built-in optimal scheme, the proposed IOL design can efficiently improve the critical parameters, namely TCO, RMS, and MTF.

  8. Influence of aspheric intraocular lens on frequency doubling technology and contrast sensitivity: a fellow eye study

    Directory of Open Access Journals (Sweden)

    Rodrigo França de Espíndola

    2014-12-01

    Full Text Available Purpose: To evaluate whether implantation of an aspheric intraocular lens (IOL results in reduced ocular aberrations and improved contrast sensitivity after cataract surgery and, therefore, changes on frequency-doubling technology (FDT testing. Methods: The present prospective clinical study enrolled 25 patients with bilateral cataract (50 eyes, who randomly received either an aspheric (Akreos AO or a spherical (Akreos Fit IOL in one eye and the other IOL in the second eye. Assessment 12 months postoperatively included photopic and mesopic contrast sensitivity testing. Higher-order aberrations (HOAs were computed. FDT testing was divided into four areas to evaluate the variation of the values at different points. The median values of the local pattern thresholds (median area contrast sensitivity [MACS] obtained with that division were calculated. Results: The Akreos AO group obtained statistically significantly lower values of HOAs and spherical aberration compared with the Akreos Fit group. There was a statistically significant between-group difference in contrast sensitivity under mesopic conditions at all spatial frequencies. No statistically significant differences were observed in mean deviation and pattern standard deviation. The aspheric IOL exhibited higher MACS in all areas, although a statistically significant difference was reached only in the 20-degree field area (P=0.043. Conclusion: Aspheric IOLs significantly reduced spherical aberration and HOAs, improving mesopic contrast sensitivity. Although there was a trend toward slightly improved FDT in the aspheric IOL group, it was not statistically significant.

  9. Solutions on a high-speed wide-angle zoom lens with aspheric surfaces

    Science.gov (United States)

    Yamanashi, Takanori

    2012-10-01

    Recent development in CMOS and digital camera technology has accelerated the business and market share of digital cinematography. In terms of optical design, this technology has increased the need to carefully consider pixel pitch and characteristics of the imager. When the field angle at the wide end, zoom ratio, and F-number are specified, choosing an appropriate zoom lens type is crucial. In addition, appropriate power distributions and lens configurations are required. At points near the wide end of a zoom lens, it is known that an aspheric surface is an effective means to correct off-axis aberrations. On the other hand, optical designers have to focus on manufacturability of aspheric surfaces and perform required analysis with respect to the surface shape. Centration errors aside, it is also important to know the sensitivity to aspheric shape errors and their effect on image quality. In this paper, wide angle cine zoom lens design examples are introduced and their main characteristics are described. Moreover, technical challenges are pointed out and solutions are proposed.

  10. Optimizing distance image quality of an aspheric multifocal intraocular lens using a comprehensive statistical design approach.

    Science.gov (United States)

    Hong, Xin; Zhang, Xiaoxiao

    2008-12-01

    The AcrySof ReSTOR intraocular lens (IOL) is a multifocal lens with state-of-the-art apodized diffractive technology, and is indicated for visual correction of aphakia secondary to removal of cataractous lenses in adult patients with/without presbyopia, who desire near, intermediate, and distance vision with increased spectacle independence. The multifocal design results in some optical contrast reduction, which may be improved by reducing spherical aberration. A novel patent-pending approach was undertaken to investigate the optical performance of aspheric lens designs. Simulated eyes using human normal distributions were corrected with different lens designs in a Monte Carlo simulation that allowed for variability in multiple surgical parameters (e.g. positioning error, biometric variation). Monte Carlo optimized results indicated that a lens spherical aberration of -0.10 microm provided optimal distance image quality.

  11. Wide-aperture aspherical lens for high-resolution terahertz imaging

    Science.gov (United States)

    Chernomyrdin, Nikita V.; Frolov, Maxim E.; Lebedev, Sergey P.; Reshetov, Igor V.; Spektor, Igor E.; Tolstoguzov, Viktor L.; Karasik, Valeriy E.; Khorokhorov, Alexei M.; Koshelev, Kirill I.; Schadko, Aleksander O.; Yurchenko, Stanislav O.; Zaytsev, Kirill I.

    2017-01-01

    In this paper, we introduce wide-aperture aspherical lens for high-resolution terahertz (THz) imaging. The lens has been designed and analyzed by numerical methods of geometrical optics and electrodynamics. It has been made of high-density polyethylene by shaping at computer-controlled lathe and characterized using a continuous-wave THz imaging setup based on a backward-wave oscillator and Golay detector. The concept of image contrast has been implemented to estimate image quality. According to the experimental data, the lens allows resolving two points spaced at 0.95λ distance with a contrast of 15%. To highlight high resolution in the THz images, the wide-aperture lens has been employed for studying printed electronic circuit board containing sub-wavelength-scale elements. The observed results justify the high efficiency of the proposed lens design.

  12. Bionic optical imaging system with aspheric solid-liquid mixed variable-focus lens

    Science.gov (United States)

    Du, Jia-Wei; Wang, Xuan-Yin; Liang, Dan

    2016-02-01

    A bionic optical imaging system with an aspheric solid-liquid mixed variable-focus lens was designed and fabricated. The entire system mainly consisted of a doublet lens, a solid-liquid mixed variable-focus lens, a connecting part, and a CCD imaging device. To mimic the structure of the crystalline lens, the solid-liquid mixed variable-focus lens consisted of a polydimethylsiloxane (PDMS) lens, a polymethyl methacrylate lens, and the liquid of ethyl silicone oil. By pumping liquid in or out of the cavity using a microinjector, the curvatures of the front and rear surfaces of the PDMS lens were varied, resulting in a change of focal length. The overall structure of the system was presented, as well as a detailed description of the solid-liquid mixed variable-focus lens, material, and fabrication process. Under different injection volumes, the deformation of the PDMS lens was measured and simulated, pictures were captured, and the optical performance was analyzed in simulations and experiments. The focal length of the system ranged from 25.05 to 14.61 mm, and the variation of the diopter was 28.5D, which was larger than that of the human eye.

  13. FEM analysis of hot-pressing process of aspheric glass P-SK57 lens

    Science.gov (United States)

    Zhu, Yongjian; Na, Jingxin; Wang, Yu; Li, Anhu; Zhi, Yanan; Fan, Yufeng

    2013-09-01

    Lens molding has become the promising technique to conduct mass produce of aspheric glass lens. It overcomes some disadvantages of traditional grinding or turning methods, such as high cost, low efficiency, unstable accuracy, and so on. Up to now, the lens molding process has been looked on as one of the reliable methods in fabrication of aspheric glass lens. However, in real production, one has found that it's hard to control the molding parameters, e.g. molding temperature, molding period, molding speed and pressing pressure, etc. Therefore it's necessary to develop the specific molding processes for a certain glass material. In this paper, SCHOTT P-SK57 is adopted to carry out the lens molding analysis in order to achieve the relative processing parameters. The molding cases are analyzed based on three different temperatures of 510°C, 520°C, and 530°C, higher than transition point 493°C of P-SK57. Through continuous heating and pressing simulation, the results show that the best pressing temperature could be about 530°C, at which the residual stress is only 5.22MPa (with the molding speed of 0.1mm/s).

  14. Designing null phase screens to test a fast plano-convex aspheric lens

    Science.gov (United States)

    DelOlmo-Márquez, Jesús; Castán-Ricaño, Diana; Avendaño-Alejo, Maximino; Díaz-Uribe, Rufino

    2015-08-01

    We have obtained a formula to represent the wavefront produced by a plano-convex aspheric lens with symmetry of revolution considering a plane wavefront propagating parallel to the optical axis and impinging on the refracting surface, it is called a zero-distance phase front, being it the first wavefront to be out of the optical system. Using a concept of differential geometry called parallel curves it is possible to obtain an analytic formula to represent the wavefront propagated at arbitrary distances through the optical axis. In order to evaluate qualitatively a plano-convex aspheric lens, we have modified slightly an interferometer Tywman-Green as follow: In the reference beam we use a plane mirror and the beam of test we have used a spatial light modulator (SLM) to compensate the phase produced by the lens under test. It will be called a null phase interferometer. The main idea is to recombine both wavefronts in order to get a null interferogram, otherwise we will associate the patterns of the interferogram to deformations of the lens under test. The null phase screens are formed with concentric circumferences assuming different gray levels printed on SLM.

  15. Three-dimensional photoacoustic imaging system with a 4f aspherical acoustic lens

    Science.gov (United States)

    Jen, En; Lin, Hsintien; Chiang, Huihua Kenny

    2016-08-01

    Photoacoustic (PA) imaging is a modality for achieving high-contrast images of blood vessels or tumors. Most PA imaging systems use complex reconstruction algorithms under conventional linear array transducers. We introduced the optical simulating method to improve the acoustic lens design and obtain a PA imaging system with improved spatial revolution (a 0.5-mm point spread function and a lateral image resolution of more than 1 mm) is realized using a 4f aspherical acoustic lens. The acoustic lens approach improved the image resolution and enabled direct reconstruction of three-dimensional (3-D) PA images. The system demonstrated a lateral resolution of more than 1 mm, a field of view of 8.5 deg, and a depth of focus of 10 mm. The system displays great potential for developing a real-time 3-D PA camera system for biomedical ultrasound imaging applications.

  16. Characteristic analysis of aspheric quasi-optical lens antenna in millimeter-wave radiometer imaging system.

    Science.gov (United States)

    Kim, Won-Gyum; Moon, Nam-Won; Singh, Manoj Kumar; Kim, Hwang-Kyeom; Kim, Yong-Hoon

    2013-02-20

    Quasi-optical imaging systems require low blurring effect and large depth of focus (DOF) to get an acceptable sharpness of the image. To reduce aberration-limited blurring, the aspheric convex plano lenses with an aperture diameter of 350 mm are designed in W-band. We analyzed theoretically and experimentally the millimeter-wave band lens characteristics, such as beam spot size, spatial resolution (SR), and DOF, via f-number. It is first used to verify the DOF through f-number in the system-level test with the developed W-band radiometer imaging system. We have confirmed that the larger f-number of quasi-optical lens leads to a larger DOF but a lower SR.

  17. Aspheric surface lens for LED collimating illumination with low Fresnel loss

    Science.gov (United States)

    Chen, Xindu; Lin, Jiaping; Liu, Zhanji; Wu, Peixuan; Wang, Han

    2017-02-01

    An aspheric surface lens is presented to realize collimating illumination with low Fresnel loss based on Fresnel equations and Snell's law. The smooth 2D contour of refractive optical surface is constructed from a set of cubic Bézier segments, whose control points are computed by deCasteljau algorithm. Simulation results show that the optical efficiency of 90.82% is achieved under a divergence angle of ±2.87° for an extended light-emitting diode (LED) source with chip size of 1 mm × 1 mm and the Fresnel loss is only 8.76%, whose optical efficiency has improved 14.3% than traditional collimating lens. By employing this proposed surface construction method, the largest divergence angle of collimating lens for point source is only 0.26° with 15 feature points on each refractive surface, while more than 2° for the traditional method. Therefore, the beams are well controlled with fewer feature data points. Tolerance analyses are also conducted in detail.

  18. Aspheric surface lens for LED collimating illumination with low Fresnel loss

    Science.gov (United States)

    Chen, Xindu; Lin, Jiaping; Liu, Zhanji; Wu, Peixuan; Wang, Han

    2016-12-01

    An aspheric surface lens is presented to realize collimating illumination with low Fresnel loss based on Fresnel equations and Snell's law. The smooth 2D contour of refractive optical surface is constructed from a set of cubic Bézier segments, whose control points are computed by deCasteljau algorithm. Simulation results show that the optical efficiency of 90.82% is achieved under a divergence angle of ±2.87° for an extended light-emitting diode (LED) source with chip size of 1 mm × 1 mm and the Fresnel loss is only 8.76%, whose optical efficiency has improved 14.3% than traditional collimating lens. By employing this proposed surface construction method, the largest divergence angle of collimating lens for point source is only 0.26° with 15 feature points on each refractive surface, while more than 2° for the traditional method. Therefore, the beams are well controlled with fewer feature data points. Tolerance analyses are also conducted in detail.

  19. Research on the processing technology of medium-caliber aspheric lens in the optoelectronic integrated test system

    Science.gov (United States)

    Liu, Dan; Yu, Xin-ying; Wang, Wei

    2016-10-01

    In the optoelectronic integrated test system, surface profile and finish of the optical element are put forward higher request. Taking an aspherical quartz glass lens with a diameter of 200mm as example, taking Preston hypothesis as the theoretical basis, analyze the influence of surface quality of various process parameters, including the workpiece and the tool axis spindle speed, wheel type, concentration polishing, polishing mold species, dwell time, polishing pressure and other parameters. Using CNC method for the surface profile and surface quality of the lens were investigated. Taking profilometer measurement results as a guide, by testing and simulation analysis, process parameters were improved constantly in the process of manufacturing. Mid and high frequency error were trimmed and improved so that the surface form gradually converged to the required accuracy. The experimental results show that the final accuracy of the surface is less than 2µm and the surface finish is, which fulfils the accuracy requirement of aspherical focusing lens in optical system.

  20. Aspherical lens design using hybrid neural-genetic algorithm of contact lenses.

    Science.gov (United States)

    Yen, Chih-Ta; Ye, Jhe-Wen

    2015-10-01

    The design of complex contact lenses involves numerous uncertain variables. How to help an optical designer to first design the optimal contact lens to reduce discomfort when wearing a pair of glasses is an essential design concern. This study examined the impact of aberrations on contact lenses to optimize a contact lens design for myopic and astigmatic eyes. In general, two aspherical surfaces can be assembled in an optical system to reduce the overall volume size. However, this design reduces the spherical aberration (SA) values at wide contact radii. The proposed optimization algorithm with optical design can be corrected to improve the SA value and, thus, reduce coma aberration (TCO) values and enhance the modulation transfer function (MTF). This means integrating a modified genetic algorithm (GA) with a neural network (NN) to optimize multiple-quality characteristics, namely the SA, TCO, and MTF, of contact lenses. When the proposed optional weight NN-GA is implemented, the weight values of the fitness function can be varied to adjust system performance. The method simplifies the selection of parameters in the optimization of optical systems. Compared with the traditional CODE V built-in optimal scheme, the proposed scheme is more flexible and intuitive to improve SA, TCO, and MTF values by 50.03%, 45.78%, and 24.7%, respectively.

  1. High order aberration and straylight evaluation after cataract surgery with implantation of an aspheric,aberration correcting monofocal intraocular lens

    Institute of Scientific and Technical Information of China (English)

    Florian; T; A; Kretz; Tamer; Tandogan; Ramin; Khoramnia; Gerd; U; Auffarth

    2015-01-01

    ·AIM: To evaluate the quality of vision in respect to high order aberrations and straylight perception after implantation of an aspheric, aberration correcting,monofocal intraocular lens(IOL).·METHODS: Twenty-one patients(34 eyes) aged 50 to83 y underwent cataract surgery with implantation of an aspheric, aberration correcting IOL(Tecnis ZCB00,Abbott Medical Optics). Three months after surgery they were examined for uncorrected(UDVA) and corrected distance visual acuity(CDVA), contrast sensitivity(CS)under photopic and mesopic conditions with and without glare source, ocular high order aberrations(HOA, Zywave II) and retinal straylight(C-Quant).· RESULTS: Postoperatively, patients achieved a postoperative CDVA of 0.0 log MAR or better in 97.1% of eyes. Mean values of high order abberations were +0.02±0.27(primary coma components) and-0.04 ±0.16(spherical aberration term). Straylight values of the C-Quant were 1.35±0.44 log which is within normal range of age matched phakic patients. The CS measurements under mesopic and photopic conditions in combination with and without glare did not show any statistical significance in the patient group observed(P ≥0.28).· CONCLUSION: The implantation of an aspherical aberration correcting monofocal IOL after cataractsurgery resulted in very low residual higher order aberration(HOA) and normal straylight.

  2. Numerical simulation of the optical characteristics of autostereoscopic displays that have an aspherical lens array with a slanted angle.

    Science.gov (United States)

    Jung, Sung-Min; Kang, In-Byeong

    2014-02-10

    We developed a 3D simulation model describing the optical phenomena on a slanted lenticular surface with aspherical lenses for autostereoscopic displays and analyzed the optical behavior of the multiview autostereoscopic display under actual design conditions by using a 3D simulation model. Optical characteristics, such as 3D crosstalk and 3D luminance differences, are obtained from the simulation of the light distribution for the multiview autostereoscopic displays with slated angles of 0.0°, 9.46°, 12.59°, and 14.04°. By investigating the effect of the conic constant of an aspherical lens surface on the 3D crosstalk and the 3D luminance differences for given several design conditions, we find the optimal values of the conic constant for slanted angles of 0.0° and 9.46° in order to minimize the 3D crosstalk and the 3D luminance difference. From these results, we think that our simulation model is very useful for designing the lens array to optimize the optical characteristics of autostereoscopic displays.

  3. Clinical Evaluation of Functional Vision of +1.5 Diopters near Addition, Aspheric, Rotational Asymmetric Multifocal Intraocular Lens

    Science.gov (United States)

    Khoramnia, Rahmin; Attia, Mary Safwat; Koss, Michael Janusz; Linz, Katharina; Auffarth, Gerd Uwe

    2016-01-01

    Purpose To evaluate postoperative outcomes and visual performance in intermediate distance after implantation of a +1.5 diopters (D) addition, aspheric, rotational asymmetric multifocal intraocular lens (MIOL). Methods Patients underwent bilateral cataract surgery with implantation of an aspheric, asymmetric MIOL with +1.5 D near addition. A complete ophthalmological examination was performed preoperatively and 3 months postoperatively. The main outcome measures were monocular and binocular uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), distance corrected intermediate visual acuity (DCIVA), uncorrected near visual acuity (UNVA) and distance corrected keratometry, and manifest refraction. The Salzburg Reading Desk was used to analyze unilateral and bilateral functional vision with uncorrected and corrected reading acuity, reading distance, reading speed, and the smallest log-scaled print size that could be read effectively at near and intermediate distances. Results The study comprised 60 eyes of 30 patients (mean age, 68.30 ± 9.26 years; range, 34 to 80 years). There was significant improvement in UDVA and CDVA. Mean UIVA was 0.01 ± 0.09 logarithm of the minimum angle of resolution (logMAR) and mean DCIVA was -0.02 ± 0.11 logMAR. In Salzburg Reading Desk analysis for UIVA, the mean subjective intermediate distance was 67.58 ± 8.59 cm with mean UIVA of -0.02 ± 0.09 logMAR and mean word count of 96.38 ± 28.32 words/min. Conclusions The new aspheric, asymmetric, +1.5 D near addition MIOL offers good results for distance visual function in combination with good performance for intermediate distances and functional results for near distance. PMID:27729759

  4. [Aspheric optics: physical fundamentals].

    Science.gov (United States)

    Mrochen, M; Büeler, M

    2008-03-01

    Especially regarding intraocular lenses and refractive corneal surgery, one finds numerous concepts on how to improve the optical quality of the human eye through aspheric optics. Aspheric optics consists of optical surfaces in which at least one surface (for example, the corneal surface) deviates from the spherical shape. An aspheric (that is, not spherical) surface enables the correction of aberrations, especially the spherical aberration, by freely shaping the optical surface. The optical aberrations of the human eye can theoretically be minimized through the use of aspheric optics; however, the results are always affected by the optical properties of the cornea and the lens. Aspheric intraocular lenses allow a reduction of postoperative spherical aberrations of the patient's eye, but an optimal individualized conformation can result only when the shape of the cornea (asphericity) is considered. By the same token, the ideal corneal asphericity after refractive surgery for an individual eye cannot be defined without knowing the optical properties of the intraocular structure. Theoretical observations of aspheric optics in refractive surgery show that with aspheric approaches, a higher optical quality for the human eye can be attained. These theoretical advantages must, however, prove themselves in everyday clinical routine.

  5. 非球面复眼设计及其制备工艺研究%Design and preparation of aspherical compound eye

    Institute of Scientific and Technical Information of China (English)

    郝永平; 李伦; 于军波

    2016-01-01

    提出了一种制备非球面仿生复眼的方法。昆虫的复眼是由一个个尺寸微小的独立小眼沿曲面小眼阵列的方式分布在头部的两侧,以实现大视角探测。设计曲面基底上阵列非均匀微透镜结构,沿径向排列的各级微透镜的焦距及尺寸均不相同。根据几何光学成像原理,计算各级微透镜的尺寸参数,对构建的模型进行光线追迹,优化各级微透镜的尺寸参数。分析不同制备技术特点,研究材料性能及不同材料间的关系,提出了可简单、快速的制备非球面仿生复眼的方法。该方法中,利用精密五轴数控机床加工非球面复眼模具,然后通过压力灌注方法将非球面复眼结构转移出来,获得所需的非球面仿生复眼。通过仿真及实验结果表明,整个曲面仿生复眼边缘成像质量明显提高,各子眼通道均能够采集清晰亮斑。%A preparation method for aspherical bionic compound eye is proposed.The compound eyes of insects are composed of many tiny independent ommatidia,and these ommatidia along the surface of the array distribute on both sides of the head to achieve large angle viewing.The array of non-uniform substrate surface is designed for micro-lens structure,and the focal lengths and sizes of radial arrayed micro-lenses are all different.According to geometrical op-tics imaging principle,size parameters of all level micro-lenses are computed,and the constructed model is carried out by ray-tracing and the size parameters of all level micro-lenses are optimized.The technical characteristics of different preparation methods are analyzed,and material properties and the relationship between different materials are studied, so a simple and fast preparation method for aspherical bionic compound eye is proposed.In this method,the mold of aspherical compound eyes is manufactured by precise five-axis CNC machine and then the aspheric compound eye structure is transferred

  6. Clinical Application of Aspheric Intraocular Lens%浅谈非球面人工晶状体的临床应用

    Institute of Scientific and Technical Information of China (English)

    许玉梅

    2016-01-01

    目的:通过非球面人工晶状体植入术后视功能的变化,观察治疗效果,提出治疗建议,客观评价非球面人工晶状体的临床作用。方法从眼球面像差的特性,非球面人工晶状体的设计及矫正目标,非球面人工晶状体临床应用注意事项,非球面人工晶状体的视觉质量评价等方面进行分析。结果虽然非球面人工晶状体眼术后的高阶像差低于球面人工晶状体,但其视力和对比敏感度的结果并不完全与之相对应。由于目前我们对人眼波前像差的认识还不够深入,检测仪器不够完善,各阶像差与视功能之间的关系尚需进一步的研究。结论正常瞳孔下非球面人工晶状体眼与球面人工晶状体眼相比,非球面人工晶体可以有效减少球面像差,提高部分空间频率的对比敏感度,使患者拥有更好地视觉质量,但其不能体现减少术眼后高阶像差的优势。%Objective Through the changes of visual function after implantation of aspheric intraocular lens(IOL)observed treatment effect,treatment recommendations,and objective evaluation of non spherical intraocular lens(IOL)clinical effect. MethodsFrom the ocular wavefront aberration characteristics,the design of aspheric intraocular lens and correctional goal and clinical application of aspheric intraocular lenses note,aspheric intraocular lens visual quality evaluation were analyzed.Results Although the high order aberrations of the patients with non spherical intraocular lens were lower than that of the spherical intraocular lens,the visual acuity and contrast sensitivity were not completely corresponding with the results. Because at present we of wavefront aberration of understanding is not deep enough,detection equipment is not perfect,aberration and depending on the relationship between function stil need to further study.Conclusion With normal pupil non compared to spherical intraocular lens eyes and spherical

  7. Influence of soft bonding layer material viscoplasticity on thermal lens and aspherical aberration of high-power thin disk laser

    Science.gov (United States)

    Wang, Mu; Zhu, Guangzhi; Zhu, Xiao; Feng, Yufan; Gao, Jiapeng

    2016-11-01

    An numerical model considering solder viscoplasticity is developed to analyze the thermal deformation of laser disk with indium bonded. The characteristic of soft bonding material is described using Anand viscoplasticity model. The Finite Element Method analytical results show that the back surface of laser disk with pumping will deform more significantly with time and finally be steady. Correspondingly the refraction power increase gradually and diffraction loss induced by aspherical aberration decrease gradually. Futhermore when pump spot is larger the refraction power and aspherical aberration will change more due to solder viscoplasticity.

  8. 非球面人工晶状体植入术后患者的生存质量%Quality of life after aspheric intraocular lens implantation

    Institute of Scientific and Technical Information of China (English)

    陈风华; 曲惠红; 闫爱民

    2009-01-01

    目的 对植入非球面人工晶状体(aspherical intraocular lens,AIOL)的效果进行评价.方法 将2007年2月至2008年2月在本院行白内障超声乳化联合人工晶状体植入术患者96例随机分成AIOL组和球面人工晶状体(spherical intraocular lens,SIOL)组,并对2组患者术后满意度和生存质量进行比较.结果 AIOL组和SIOL组患者总满意率分别为42例(87.50%)和28例(58.33%),差异有显著统计学意义(P<0.01).AIOL组和SIOL组患者半年后视物舒适度及暗适应功能分值经比较,差异均有显著统计学意义(t=5.746 1,P<0.001;t=2.959 7,P<0.01).结论 AIOL值得在临床推广.

  9. 基于粘刚塑性模型非球面透镜三维模压成型模拟%Simulation of 3D molding of aspheric optical glass lens based on viscous-rigid model

    Institute of Scientific and Technical Information of China (English)

    张小兵

    2015-01-01

    The temperature dependence of flow stress model and glass material parameters at high temperature was analyzed and discussed. The three⁃dimensional finite element model of compression molding of aspheric lens at high temperature was established using viscous⁃rigid model based on DEFORM 3D. The whole process of optical glass spherical L⁃BAL42 preform being molded into aspheric lens was studied by numerical simulation. It is found that maximum stress is at lens edge and stresses increase rapidly when mold is closed,leading to the lens edge most easily being broken,the result is validated by experiments. Residual stress will increase with increasing compression rate and the cooling rate,and the rules of aspheric lens deviation were analyzed. Finally aspheric surface deviation was compensated during the mold design stage. It is found that the aspheric surface deviation will decrease,deviation changes from positive to negative.%分析与探讨了高温玻璃的应力流动模型及其材料参数的温度相关性。利用粘刚塑性力学模型,基于三维有限元软件DEFORM 3D建立非球面透镜高温模压有限元模型,对光学玻璃L-BAL42球形预制件模压成非球面透镜的整个过程进行了数值仿真,发现非球面透镜应力分布规律:透镜边缘处应力最大,在和模阶段应力快速增加,导致透镜边缘处最易破碎,结果得到实验的验证。采用较大的模压速度及冷却速度将导致残余应力增加,同时分析了透镜非球面偏差变化规律。最后在模具设计时将非球面偏差补偿进去,发现非球面透镜偏差减少,由正偏差变为负偏差。

  10. High brightness three-dimensional light field display based on the aspheric substrate Fresnel-lens-array with eccentric pupils

    Science.gov (United States)

    Gao, Xin; Sang, Xinzhu; Yu, Xunbo; Cao, Xuemei; Chen, Zhidong; Yan, Binbin; Yuan, Jinhui; Wang, Kuiru; Yu, Chongxiu; Dou, Wenhua; Xiao, Liquan

    2016-02-01

    The brightness and viewing field of the reproductive three-dimensional (3D) image are crucial factors to realize a comfortable 3D perception for the light field display based on the liquid crystal device (LCD). To improve the illuminance of 3D image with sub-image-units with small aperture angles and enlarge the viewing field, the illuminance of the Fresnel-lens combining with the sub-images on LCD is analyzed and designed. Theoretical and experimental results show that the Fresnel-lens-array with eccentric pupil(FAEP) can address above problems. A 3D light field display based on LCD with FAEP and directional diffuser screen are used to reconstruct the target 3D field. 25 parallax sub-images are projected to the directional diffuser screen to verify the improvement of illuminance and viewing field. To reduce eccentric aberration introduced by eccentric pupil, a novel structure of Fresnel-lens-array is presented to reduce the aberration. The illuminance and viewing field are well promoted at the same time. 3D image with the high quality can be achieved.

  11. Visual acuity and patient satisfaction at varied distances and lighting conditions after implantation of an aspheric diffractive multifocal one-piece intraocular lens

    Science.gov (United States)

    Chang, Daniel H

    2016-01-01

    Purpose The aim of the study is to evaluate the visual acuity and patient satisfaction at varied distances under photopic and mesopic lighting conditions in patients bilaterally implanted with aspheric diffractive multifocal one-piece intraocular lenses. Methods In this retrospective–prospective study, 16 patients with a mean age of 66.2±9.2 years (range: 50–81 years) who had undergone bilateral phacoemulsification surgery with implantation of a Tecnis multifocal one-piece intraocular lens (ZMB00) were evaluated. Monocular and binocular uncorrected and distance-corrected visual acuities were measured at distance (20 ft), intermediate (70–80 cm), and near (35–40 cm) under photopic (85 cd/m2) and mesopic (3 cd/m2) lighting conditions and were compared using the paired t-test. All patients also completed a subjective questionnaire. Results At a mean follow-up of 9.5±3.9 months, distance, near, and intermediate visual acuity improved significantly from preoperative acuity. Under photopic and mesopic conditions, 93.8% and 62.5% of patients, respectively, had binocular uncorrected intermediate visual acuity of 20/40 or better, and 62.5% and 31.3% of patients had binocular uncorrected near visual acuity of 20/20 or better. All patients were satisfied with their overall vision without using glasses and/or contact lenses when compared with before surgery. A total of 87.5% of patients reported no glare and 68.8% of patients reported no halos around lights at night. Conclusion Tecnis multifocal one-piece intraocular lenses provide good distance, intermediate, and near visual acuity under photopic as well as mesopic lighting conditions. High levels of spectacle independence with low levels of photic phenomenon were achieved, resulting in excellent patient satisfaction. PMID:27536061

  12. Effect of aspherical and yellow tinted intraocular lens on blue-on-yellow perimetry Efeito das lentes intraoculares asféricas e com pigmentação amarela na campimetria azul-amarelo

    Directory of Open Access Journals (Sweden)

    Rodrigo França de Espíndola

    2012-10-01

    Full Text Available PURPOSE: To investigate the possible effect of aspherical or yellow tinted intraocular lens (IOL on contrast sensitivity and blue-on-yellow perimetry. METHODS: This prospective randomized bilateral double-masked clinical study included 52 patients with visually significant bilateral cataracts divided in two groups; 25 patients (50 eyes received aspherical intraocular lens in one eye and spherical intraocular lens in the fellow eye; and 27 patients (54 eyes received ultraviolet and blue light filter (yellow tinted IOL implantation in one eye and acrylic ultraviolet filter IOL in the fellow eye. The primary outcome measures were contrast sensitivity and blue-on-yellow perimetry values (mean deviation [MD] and pattern standard deviation [PSD] investigated two years after surgery. The results were compared intra-individually. RESULTS: There was a statistically significant between-group (aspherical and spherical intraocular lens difference in contrast sensitivity under photopic conditions at 12 cycles per degree and under mesopic conditions at all spatial frequencies. There were no between-group significant differences (yellow tinted and clear intraocular lens under photopic or mesopic conditions. There was no statistically significant difference between all intraocular lens in MD or PSD. CONCLUSION: Contrast sensitivity was better under mesopic conditions with aspherical intraocular lens. Blue-on-yellow perimetry did not appear to be affected by aspherical or yellow tinted intraocular lens. Further studies with a larger sample should be carried out to confirm or not that hypotheses.OBJETIVO: Investigar a possibilidade de efeitos na sensibilidade ao contraste e nos resultados da campimetria azul-amarelo com implante de uma lente intraocular (LIO asférica ou de pigmentação amarela. MÉTODOS: Trata-se de um estudo prospectivo, randomizado, duplo-mascarado, envolvendo 52 pacientes portadores de catarata senil bilateral, divididos em dois grupos; 25

  13. Characteristics of corneal lens chitin in dragonfly compound eyes.

    Science.gov (United States)

    Kaya, Murat; Sargin, Idris; Al-Jaf, Ivan; Erdogan, Sevil; Arslan, Gulsin

    2016-08-01

    Chitin in the compound eyes of arthropods serves as a part of the visual system. The quality of chitin in such highly specialised body parts deserves more detailed examination. Chitin in the corneal (ommatidial) lenses of dragonfly (Sympetrum fonscolombii) compound eyes was isolated by using the classical chemical method. The chitin content of the corneal lenses was determined to be quite high (20.3±0.85%). The FT-IR analysis showed that corneal lens chitin was in the α-form as found in all arthropod species where mechanical strength is required. The surface morphology analysis by scanning electron microscopy revealed that the outer part of corneal lenses consisted of long chitin fibrils with regular arrays of papillary structures while the smoother inner part had concentric lamellated chitin formation with shorter chitin nanofibrils. Chitinase enzymatic digestion studies, elemental analysis results and the degree of acetylation value showed the purity of chitin samples from corneal lens. The maximum degradation temperature value of the corneal lens chitin was observed at 369.2°C. X-ray analysis revealed that corneal lens chitin has high crystallinity index; 96.4%. Identification of chitin found in ommaditia of insect compound eyes can provide insights into insect vision and chitin-based optical material design studies.

  14. Desempenho visual após implante de uma lente intraocular asférica multifocal difrativa Visual performance after implantation of an aspheric multifocal diffractive intraocular lens

    Directory of Open Access Journals (Sweden)

    Leonardo Akaishi

    2010-08-01

    Full Text Available OBJETIVO: Avaliar a acuidade visual a distancia, intermediária e perto após o implante de uma lente intraocular (LIO asférica multifocal difrativa AcrySof® ReSTOR® SN6AD1. MÉTODOS: Estudo prospectivo de 50 pacientes com catarata submetidos à facoemulsificação e implante de LIO AcrySof® ReSTOR®. Foram avaliados acuidade visual sem correção (AVSC, acuidade visual com correção (AVCC para longe, acuidade visual para perto corrigida para longe (AVPC e acuidade visual intermediária corrigida para longe (AVIC. Um questionário de satisfação e fenômenos visuais foi administrado ao final do estudo. RESULTADO: Após três meses de cirurgia, a média das acuidades (logMAR era: AVSC, 0,05 ± 0,07; AVCC, 0,00 ± 0,01; AVPC, 0,00 ± 0,0, e AVIC, 0,15 ± 0,05. A AVCC e AVPC era de 20/25 ou melhor em todos os pacientes, sendo a AVIC J3 ou melhor em 83% dos pacientes. Pacientes relataram excelente desempenho visual nas questões relacionadas a atividades para distância, intermediário, e perto com pouca ou nenhuma dificuldade. Nenhum paciente relatou halos ou 'glare' severos, sendo os mesmos caracterizados entre nenhum a moderado. CONCLUSÃO: A LIO asférica AcrySof® ReSTOR® SN6AD1 mostrou excelentes resultados na visão para longe, perto e intermediário, além de apresentar uma baixa incidência de fenômenos visuais.PURPOSE: To evaluate distance, intermediate, and near vision after aspheric multifocal diffractive AcrySof® ReSTOR® SN6AD1 intraocular lens (IOL implantation. METHODS: Prospective study of 50 patients with cataract that had phacoemulsification and AcrySof® ReSTOR® IOL implantation. Uncorrected distance vision acuity (UDVA, corrected distance visual acuity (CDVA, distance-corrected near visual acuity (DCNVA, and distance-corrected intermediate visual acuity (DCIVA were measured postoperatively. A patient-satisfaction and visual phenomena questionnaire was administered at the end of the study. RESULTS: Three months

  15. Visual acuity and patient satisfaction at varied distances and lighting conditions after implantation of an aspheric diffractive multifocal one-piece intraocular lens

    Directory of Open Access Journals (Sweden)

    Chang DH

    2016-08-01

    Full Text Available Daniel H Chang Empire Eye and Laser Center, Bakersfield, CA, USA Purpose: The aim of the study is to evaluate the visual acuity and patient satisfaction at varied distances under photopic and mesopic lighting conditions in patients bilaterally implanted with aspheric diffractive multifocal one-piece intraocular lenses. Methods: In this retrospective–prospective study, 16 patients with a mean age of 66.2±9.2 years (range: 50–81 years who had undergone bilateral phacoemulsification surgery with implantation of a Tecnis multifocal one-piece intraocular lens (ZMB00 were evaluated. Monocular and binocular uncorrected and distance-corrected visual acuities were measured at distance (20 ft, intermediate (70–80 cm, and near (35–40 cm under photopic (85 cd/m2 and mesopic (3 cd/m2 lighting conditions and were compared using the paired t-test. All patients also completed a subjective questionnaire. Results: At a mean follow-up of 9.5±3.9 months, distance, near, and intermediate visual acuity improved significantly from preoperative acuity. Under photopic and mesopic conditions, 93.8% and 62.5% of patients, respectively, had binocular uncorrected intermediate visual acuity of 20/40 or better, and 62.5% and 31.3% of patients had binocular uncorrected near visual acuity of 20/20 or better. All patients were satisfied with their overall vision without using glasses and/or contact lenses when compared with before surgery. A total of 87.5% of patients reported no glare and 68.8% of patients reported no halos around lights at night. Conclusion: Tecnis multifocal one-piece intraocular lenses provide good distance, intermediate, and near visual acuity under photopic as well as mesopic lighting conditions. High levels of spectacle independence with low levels of photic phenomenon were achieved, resulting in excellent patient satisfaction. Keywords: Tecnis multifocal one-piece IOL, photopic visual acuity, mesopic visual acuity, intermediate visual

  16. Aspherical supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Kasen, Daniel Nathan

    2004-05-21

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new break throughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi-dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally, we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3

  17. Aspherical supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Kasen, Daniel Nathan [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    Although we know that many supernovae are aspherical, the exact nature of their geometry is undetermined. Because all the supernovae we observe are too distant to be resolved, the ejecta structure can't be directly imaged, and asymmetry must be inferred from signatures in the spectral features and polarization of the supernova light. The empirical interpretation of this data, however, is rather limited--to learn more about the detailed supernova geometry, theoretical modeling must been undertaken. One expects the geometry to be closely tied to the explosion mechanism and the progenitor star system, both of which are still under debate. Studying the 3-dimensional structure of supernovae should therefore provide new break throughs in our understanding. The goal of this thesis is to advance new techniques for calculating radiative transfer in 3-dimensional expanding atmospheres, and use them to study the flux and polarization signatures of aspherical supernovae. We develop a 3-D Monte Carlo transfer code and use it to directly fit recent spectropolarimetric observations, as well as calculate the observable properties of detailed multi-dimensional hydrodynamical explosion simulations. While previous theoretical efforts have been restricted to ellipsoidal models, we study several more complicated configurations that are tied to specific physical scenarios. We explore clumpy and toroidal geometries in fitting the spectropolarimetry of the Type Ia supernova SN 2001el. We then calculate the observable consequences of a supernova that has been rendered asymmetric by crashing into a nearby companion star. Finally, we fit the spectrum of a peculiar and extraordinarily luminous Type Ic supernova. The results are brought to bear on three broader astrophysical questions: (1) What are the progenitors and the explosion processes of Type Ia supernovae? (2) What effect does asymmetry have on the observational diversity of Type Ia supernovae, and hence their use in cosmology? (3

  18. Convex Aspherical Surface Testing Using Catadioptric Partial Compensating System

    Science.gov (United States)

    Wang, Jingxian; Hao, Qun; Hu, Yao; Wang, Shaopu; Li, Tengfei; Tian, Yuhan; Li, Lin

    2016-01-01

    Aspheric optical components are the indispensable part of modern optics systems. With the constant development of aspheric optical fabrication technique, the systems with large aperture convex aspheric optical components are widely used in astronomy and space optics. Thus, the measurement of the figure error of the whole convex aspherical surface with high precision comes to be a challenge in the area of optical surface manufacture, and surface testing method is also very important. This paper presents a new partial compensating system by the combination of a refractive lens and a reflective mirror for testing convex aspherical surface. The refractive lens is used to compensate the aberration of the tested convex asphere partially. The reflective mirror is a spherical mirror which is coaxial to the refractive lens and reflecting the lights reflected by the tested convex asphere back to the convex asphere itself. With the long focal length and large aperture system we can realize a lighter and more compact system than the refractive partial compensating system because the spheric reflective mirror is more easily to realize and can bending the light conveniently.

  19. Aspherical-atom modeling of coordination compounds by single-crystal X-ray diffraction allows the correct metal atom to be identified.

    Science.gov (United States)

    Dittrich, Birger; Wandtke, Claudia M; Meents, Alke; Pröpper, Kevin; Mondal, Kartik Chandra; Samuel, Prinson P; Amin Sk, Nurul; Singh, Amit Pratap; Roesky, Herbert W; Sidhu, Navdeep

    2015-02-02

    Single-crystal X-ray diffraction (XRD) is often considered the gold standard in analytical chemistry, as it allows element identification as well as determination of atom connectivity and the solid-state structure of completely unknown samples. Element assignment is based on the number of electrons of an atom, so that a distinction of neighboring heavier elements in the periodic table by XRD is often difficult. A computationally efficient procedure for aspherical-atom least-squares refinement of conventional diffraction data of organometallic compounds is proposed. The iterative procedure is conceptually similar to Hirshfeld-atom refinement (Acta Crystallogr. Sect. A- 2008, 64, 383-393; IUCrJ. 2014, 1,61-79), but it relies on tabulated invariom scattering factors (Acta Crystallogr. Sect. B- 2013, 69, 91-104) and the Hansen/Coppens multipole model; disordered structures can be handled as well. Five linear-coordinate 3d metal complexes, for which the wrong element is found if standard independent-atom model scattering factors are relied upon, are studied, and it is shown that only aspherical-atom scattering factors allow a reliable assignment. The influence of anomalous dispersion in identifying the correct element is investigated and discussed.

  20. Optical beam-shaping design based on aspherical lenses for circularization collimation, and expansion of elliptical laser beams

    Science.gov (United States)

    Serkan, Mert; Kirkici, Hulya

    2008-01-01

    We present two optical system designs using aspherical lenses for beam circularization, collimation, and expansion of semiconductor lasers for possible application in lidar systems. Two different optical lens systems are investigated; namely, two aspherical lens and single aspherical lens systems. Software package programs of ZEMAX and MATLAB to simulate the optical designs are used. The beam reshaping results are presented for one specific laser beam output.

  1. The role of compound lens in optimizing the irradiation uniformity in longitudinal pumping laser

    Institute of Scientific and Technical Information of China (English)

    Li Han-Ming; Li Ying-Jun; Zhang Jie

    2004-01-01

    In order to optimize the axial irradiation uniformity of a laser in plasma, this paper investigates the role played by the compound lens using a ray-tracing method. Obtained results show that the adoption of the compound lens is capable of increasing the axial line-focus length. Meanwhile, after the energy attenuation in the plasma has been considered,moderating the optical parameter of the compound lens to obtain the corresponding energy output to compensate for the attenuation optimizes the irradiation uniformity along the focal line.

  2. Clinical application of implantation of blue light-filtering aspheric intraocular lens by micro incision%微切口预装式蓝光滤过非球面人工晶状体临床应用

    Institute of Scientific and Technical Information of China (English)

    刘汝瑜; 宋慧; 汤欣; 魏荫娟

    2015-01-01

    Objective To compare the surgically induced astigmatism (SIA) of 2.0mm coaxial microincision cataract surgery (MICS) with 3.0mm small-incision cataract surgery (SICS) with blue light-filtering aspheric intraocular lens (IOL) implantation.Methods Retrospective case series of 48 cataract eyes undertaken phacoemulsification and IOL implantation from October 2012 to January 2013.MICS:26 eyes with 1-piece blue light-filtering aspheric intraocular lens by micro incision (iSert1,HOYA);SICS:22 eyes with 3-piece blue light-filtering aspheric intraocular lens by small incision (PY60AD,HOYA).Anterior chamber depth after mydriasis,corneal astigmatism,tilt and deviation of IOLs were measured using Scheimpflug system (Pentacam,Oculus) and analyzed with Image-pro plus 6.0 software.Slit lamp anterior segment photography and photoshop7.0 analyzed IOL rotation.Follow up was I week and 1 month.Results A significant SIA difference was found 1 week after surgery (P <0.05),no significant difference was found 1 month after surgery (P >0.05).With dilated pupil,there was a significant difference a month after surgery (P <0.05).No significant difference was found 1 week after surgery (P >0.05).Deviation,tilt and rotation of IOLs between the two groups showed no statistical significance (P >0.05).Conclusions Preloaded blue light-filtering aspheric intraocular lens by micro incision causes smaller SIA,is favor for visual recovery in short-term postoeration.%目的 观察2.0 mm同轴微切口白内障超声乳化(microincision cataract surgery,MICS)吸除术后植入微切口预装式蓝光滤过非球面人工晶状体(IOL)的手术源性散光(surgically induced astigmatism,SIA)及囊袋内稳定性,并与传统3.0 mm小切口白内障超声乳化(small-incision cataract surgery,SICS)手术进行比较.方法 回顾性系列病例研究.回顾性分析天津市眼科医院白内障中心于2012年10月至2013年1月白内障患者48只眼行超声乳化白

  3. Design and fabrication of one-dimensional focusing X-ray compound lens with Al material

    Institute of Scientific and Technical Information of China (English)

    Zichun Le; Ming Zhang; Jingqiu Liang; Wen Dong; Kai Liu; Bisheng Quan

    2006-01-01

    @@ A method based on Fourier spectrum analysis for predicting the performances of the X-ray compound lenses is briefly introduced,the theoretical result obtained is the same as that of Fresnel-Kirchhoff approach.A kind of technique named moulding is developed for fabricating the one-dimensional (1D) compound X-ray lens with Al material and the fabrication process is presented.In addition,a two-time coating method is used to improve the numerical apertures of the compound lenses.Furthermore,the focusing performance of the Al compound X-ray lens under the high energy X-rays is measured.

  4. PKS 1830-211: A Possible Compound Gravitational Lens

    Science.gov (United States)

    Lovell, J. E. J.; Reynolds, J. E.; Jauncey, D. L.; Backus, P. R.; McCullock, P. M.; Sinclair, M. W.; Wilson, W. E.; Tzioumis, A. K.; Gough, R. G.; Ellingsen, S. P.; Phillips, C. J.; Preston, R. A.; Jones, D. L.

    1996-01-01

    Measurements of the properties of gravitational lenses have the power to tell us what sort of universe we live in. The brightest known radio Einstein ring/gravitational lens PKS 1830-211, whilst obscured by our Galaxy at optical wavelengths, has recently provided a lensing galaxy redshift of 0.89 through the detection of molecular absorption in the millimetre waveband.

  5. 非球面人工晶状体度数计算的最优化%Preliminary evaluation of an algorithm to minimize the power error selection of an aspheric intraocular lens by optimizing the estimation of the corneal power and the effective lens position

    Institute of Scientific and Technical Information of China (English)

    DavidP Piero; VicenteJ Camps; MaraL Ramn; VernicaMateo; Roberto Soto-Negro

    2016-01-01

    目的::通过评价非球面人工晶状体( intraocular lens, IOL)屈光度的可预测性,初步开发一种计算屈光度( PIOL )的优化算法。方法:本研究纳入植入非球面 IOL ( LENTIS L-313, Oculentis GmbH)65眼,并分为2组:A组8例12眼,PIOL≥23.0D;B组35例53眼,PIOL<23.0D。术后3mo进行屈光度可预测性评价。参考角膜屈光力估计所致的可变性屈光指数计算出校正的IOL度数( PIOLadj )及屈光结果,根据年龄和解剖学因素得出校正的有效晶状体位置( adjusted effective lens position, ELPadj )。结果:术后A、B两组等效球镜度数分别为-0.75~+0.75 D、-1.38~+0.75D。 A、B两组的PIOLadj和实际晶状体屈光度(PIOLReal)之间无统计学差异(P=0.64、0.82)。 Bland-Altman分析显示A、B两组PIOLadj和PIOLReal之间的一致性区间分别为+1.11~-0.96 D和+1.14~-1.18 D。 Hoffer Q公式和Holladay I公式计算PIOLadj和PIOL之间存在临床和统计学上的显著差异(P<0.01)。结论:植入非球面IOL白内障手术的屈光可预测性可通过平行轴光学联合线性法则使角膜屈光力及晶状体位置相关误差最小化。%•AIM: To evaluate the refractive predictability achieved with an aspheric intraocular lens ( IOL ) and to develop a preliminary optimized algorithm for the calculation of its power ( PIOL ) .•METHODS:This study included 65 eyes implanted with the aspheric IOL LENTIS L-313 ( Oculentis GmbH ) that were divided into 2 groups:12 eyes (8 patients) with PIOL≥23. 0 D (group A), and 53 eyes (35 patients) with PIOL<23. 0 D ( group B ). The refractive predictability was evaluated at 3mo postoperatively. An adjusted IOL power ( PIOLadj ) was calculated considering a variable refractive index for corneal power estimation, the refractive outcome obtained, and an adjusted effective lens position ( ELPadj ) according to age and anatomical factors.•RESULTS: Postoperative spherical equivalent ranged from -0. 75 to +0. 75 D and from -1

  6. Design of Novel Compound Fresnel Lens for High-Performance Photovoltaic Concentrator

    Directory of Open Access Journals (Sweden)

    Lei Jing

    2012-01-01

    Full Text Available We present a new design of compound Fresnel-R concentrator which is composed of two lenses: a primary lens (Fresnel lens that works by total internal reflection at outer sawteeth but refraction at inner sawteeth, and a ringed secondary lens that works by refraction. In contrast to previous Fresnel lens concentrators, this design increases the acceptance angle, improves the irradiance uniformity on the solar cell, and reduces the aspect ratio significantly. Meanwhile several sawteeth of the primary Fresnel lens can correspond to a same ring of secondary lens, which will efficiently lower the complexity of designing and manufacturing. Moreover, in order to reduce the influence of manufacturing tolerances and to increase the optical efficiency further, the central part of the bottom of the secondary lens which directly adhered to the solar cell is designed as a cone-shaped prism to collect the sunlight that does not reach the solar cell. Finally, we provide simulations and analyses of the design method an optical efficiency more than 80% and an aspect ratio smaller than 0.5 can be achieved.

  7. Non-null annular subaperture stitching interferometry for aspheric test

    Science.gov (United States)

    Zhang, Lei; Liu, Dong; Shi, Tu; Yang, Yongying; Chong, Shiyao; Miao, Liang; Huang, Wei; Shen, Yibing; Bai, Jian

    2015-10-01

    A non-null annular subaperture stitching interferometry (NASSI), combining the subaperture stitching idea and non-null test method, is proposed for steep aspheric testing. Compared with standard annular subaperture stitching interferometry (ASSI), a partial null lens (PNL) is employed as an alternative to the transmission sphere, to generate different aspherical wavefronts as the references. The coverage subaperture number would thus be reduced greatly for the better performance of aspherical wavefronts in matching the local slope of aspheric surfaces. Instead of various mathematical stitching algorithms, a simultaneous reverse optimizing reconstruction (SROR) method based on system modeling and ray tracing is proposed for full aperture figure error reconstruction. All the subaperture measurements are simulated simultaneously with a multi-configuration model in a ray-tracing program, including the interferometric system modeling and subaperture misalignments modeling. With the multi-configuration model, full aperture figure error would be extracted in form of Zernike polynomials from subapertures wavefront data by the SROR method. This method concurrently accomplishes subaperture retrace error and misalignment correction, requiring neither complex mathematical algorithms nor subaperture overlaps. A numerical simulation exhibits the comparison of the performance of the NASSI and standard ASSI, which demonstrates the high accuracy of the NASSI in testing steep aspheric. Experimental results of NASSI are shown to be in good agreement with that of Zygo® VerifireTM Asphere interferometer.

  8. Focusing high-energy x-rays by a PMMA compound x-ray lens on Beijing synchrotron radiation facility

    Institute of Scientific and Technical Information of China (English)

    Le Zi-Chun; Liang Jing-Qiu; Dong Wen; Zhu Pei-Ping; Peng Liang-Qiang; Wang Wei-Biao; Huang Wan-Xia; Yuan Qing-Xi; Wang Jun-Yue

    2007-01-01

    The x-ray compound lens is a novel refractive x-ray optical device. This paper reports the authors' recent research on a polymethyl methacrylate (PMMA) compound x-ray lens. Firstly the designing and LIGA fabrication process for the PMMA compound x-ray lens are briefly described. Then, a method for theoretical analysis, as well as the experimental system for measurement is also introduced. Finally, the focusing spots for 8keV monochromatic x-rays by the PMMA compound x-ray lens are measured and analysed. According to the experimental results, it is concluded that the PMMA compound x-ray lens promises a good focusing performance under the high-energy x-rays.

  9. Simulating and optimizing compound refractive lens-based X-ray microscopes

    Science.gov (United States)

    Simons, Hugh; Ahl, Sonja Rosenlund; Poulsen, Henning Friis; Detlefs, Carsten

    2017-01-01

    A comprehensive optical description of compound refractive lenses (CRLs) in condensing and full-field X-ray microscopy applications is presented. The formalism extends ray-transfer matrix analysis by accounting for X-ray attenuation by the lens material. Closed analytical expressions for critical imaging parameters such as numerical aperture, spatial acceptance (vignetting), chromatic aberration and focal length are provided for both thin- and thick-lens imaging geometries. These expressions show that the numerical aperture will be maximized and chromatic aberration will be minimized at the thick-lens limit. This limit may be satisfied by a range of CRL geometries, suggesting alternative approaches to improving the resolution and efficiency of CRLs and X-ray microscopes.

  10. Error analysis and system optimization of non-null aspheric testing system

    Science.gov (United States)

    Luo, Yongjie; Yang, Yongying; Liu, Dong; Tian, Chao; Zhuo, Yongmo

    2010-10-01

    A non-null aspheric testing system, which employs partial null lens (PNL for short) and reverse iterative optimization reconstruction (ROR for short) technique, is proposed in this paper. Based on system modeling in ray tracing software, the parameter of each optical element is optimized and this makes system modeling more precise. Systematic error of non-null aspheric testing system is analyzed and can be categorized into two types, the error due to surface parameters of PNL in the system modeling and the rest from non-null interferometer by the approach of error storage subtraction. Experimental results show that, after systematic error is removed from testing result of non-null aspheric testing system, the aspheric surface is precisely reconstructed by ROR technique and the consideration of systematic error greatly increase the test accuracy of non-null aspheric testing system.

  11. Asphere, O asphere, how shall we describe thee?

    Science.gov (United States)

    Forbes, G. W.; Brophy, C. P.

    2008-09-01

    Two key criteria govern the characterization of nominal shapes for aspheric optical surfaces. An efficient representation describes the spectrum of relevant shapes to the required accuracy by using the fewest decimal digits in the associated coefficients. Also, a representation is more effective if it can, in some way, facilitate other processes - such as optical design, tolerancing, or direct human interpretation. With the development of better tools for their design, metrology, and fabrication, aspheric optics are becoming ever more pervasive. As part of this trend, aspheric departures of up to a thousand microns or more must be characterized at almost nanometre precision. For all but the simplest of shapes, this is not as easy as it might sound. Efficiency is therefore increasingly important. Further, metrology tools continue to be one of the weaker links in the cost-effective production of aspheric optics. Interferometry particularly struggles to deal with steep slopes in aspheric departure. Such observations motivated the ideas described in what follows for modifying the conventional description of rotationally symmetric aspheres to use orthogonal bases that boost efficiency. The new representations can facilitate surface tolerancing as well as the design of aspheres with cost-effective metrology options. These ideas enable the description of aspheric shapes in terms of decompositions that not only deliver improved efficiency and effectiveness, but that are also shown to admit direct interpretations. While it's neither poetry nor a cure-all, an old blight can be relieved.

  12. 两种不同攀设计非球面人工晶状体伪调节相关研究%Changes of pseudophakic accommodation of aspheric intraocular lens designs in phacoemulsification

    Institute of Scientific and Technical Information of China (English)

    赵玉琴; 李英俊; 金龙山

    2015-01-01

    Objective To compare the pseudophakic accommodation of different designs of aspheric intraocular lens (IOL) in phacoemulsification.Methods One hundred and twenty-six eyes with cataract surgery were randomized into 2 groups:an Acrysof IQ SN60WF (Alcon Laboratories,Fort Worth,Texas,USA) IOL group (59 eyes) and Akreos Adapt AO (Bausch & Lomb.,Rochester,NY,USA)IOL group (67 eyes).Patients were examined using anterior segment optical coherence tomography (AS-OCT),including anterior chamber depth (ACD),pupil diameter,and amplitude of pseudophakic accommodation,preoperatively and 6 months postoperatively.Results The IQ IOLs and AO IOLs group of mean pseudophakic accommodation was (1.26±0.34)D and (1.09±0.51)D,respectively,there was statistically significantly different (t =2.314,P =0.041).The mean pupil diameter measurements for IQ group and AO IOL group were (0.52±0.20)mm and (0.49±0.16)mm,respectively,which showed no statistically significant differences (t =0.946,P =0.541).The amplitude of pseudophakic accommodation was negative correlated with pupil diameter (r =-0.651,P =0.024).Conclusions The movement of aspheric IOLs in eyes after cataract surgery is an important mechanism for attaining good near vision without additional correction,2-point haptic design IOLs provide better pseudophakic accommodation than that of Four-point haptic designs.%目的 比较两种不同攀设计的非球面人工晶状体在囊袋内植入后伪调节力的差异.方法 临床病例对照研究.选择2012年5~12月在延边大学附属医院眼科行超声乳化白内障摘除联合人工晶状体植入术的老年性白内障患者82例(126只眼),应用随机数字表法髓机分为两组,SN60WF为IQ组植入“L”形Acrysof IQ SN60WF (Alcon Laboratories,Fort Worth,Texas,USA)人工晶状体(59只眼);Adapt AO为AO组植入一体四点Akreos Adapt AO (Bausch&Lomb,Rochester,NY,USA)人工晶状体(67只眼).采用眼前段光学相干断层扫描仪(AS-OCT)实时测量人工晶

  13. Breathing life into aspheric dreams

    Science.gov (United States)

    Fuchs, Ulrike; Kiontke, Sven R.

    2016-06-01

    Introducing aspheric lenses in optical design broadens the horizons of possibilities and opens up new way to correct aberrations or creating effects that are not possible otherwise. Manufacturing these aspheric surfaces has come a long way during the last 15 years. This article discusses the state of the art concerning optical design, manufacturing, surface form tolerances and roughness to show the possibilities in hand.

  14. Topological in-plane polarized piezo actuation for compact adaptive lenses with aspherical correction

    CERN Document Server

    Lemke, Florian; Wallrabe, Ulrike; Wapler, Matthias C

    2016-01-01

    In this contribution, we investigate the effects of using in-plane polarized piezo actuators with topological buckling displacement to drive glass-piezo composite membranes for adaptive lenses with aspherical control. We find that the effects on the focal power and aspherical tuning range are relatively small, whereas the tuning speed is improved significantly with a first resonance of 1 kHz for a 13 mm aperture lens.

  15. Aspherics in spectacle lenses

    Science.gov (United States)

    Dürsteler, Juan Carlos

    2016-12-01

    A review of the use of aspherics in the last decades, understood in a broad sense as encompassing single-vision lenses with conicoid surfaces and free-form and progressive addition lenses (PALs) as well, is provided. The appearance of conicoid surfaces to correct aphakia and later to provide thinner and more aesthetically appealing plus lenses and the introduction of PALs and free-form surfaces have shaped the advances in spectacle lenses in the last three decades. This document basically considers the main target optical aberrations, the idiosyncrasy of single lenses for correction of refractive errors and the restrictions and particularities of PAL design and their links to science vision and perception.

  16. Pink-beam focusing with a one-dimensional compound refractive lens.

    Science.gov (United States)

    Dufresne, Eric M; Dunford, Robert W; Kanter, Elliot P; Gao, Yuan; Moon, Seoksu; Walko, Donald A; Zhang, Xusheng

    2016-09-01

    The performance of a cooled Be compound refractive lens (CRL) has been tested at the Advanced Photon Source (APS) to enable vertical focusing of the pink beam and permit the X-ray beam to spatially overlap with an 80 µm-high low-density plasma that simulates astrophysical environments. Focusing the fundamental harmonics of an insertion device white beam increases the APS power density; here, a power density as high as 500 W mm(-2) was calculated. A CRL is chromatic so it does not efficiently focus X-rays whose energies are above the fundamental. Only the fundamental of the undulator focuses at the experiment. A two-chopper system reduces the power density on the imaging system and lens by four orders of magnitude, enabling imaging of the focal plane without any X-ray filter. A method to measure such high power density as well as the performance of the lens in focusing the pink beam is reported.

  17. Ultra-precision diamond milling of aspheric microlens array

    Science.gov (United States)

    Chen, Chun-Chieh; Huang, Chien-Yao; Cheng, Yuan-Chieh; Hsu, Wei-Yao

    2013-06-01

    The applications of AMLA (aspheric micro lens array) have been frequently required in opto-electro industries, such as optical communication, contact image sensor (CIS) module of scanner, wafer level optics, etc. In addition to the typical requirements of aspheric lens, for instance form accuracy and surface roughness, the pitch error of each micro lens has been highly required. Three ultra-precision freeform machining methods have been widely applied for the manufacturing of AMLA, namely fast tool servo, slow tool servo and diamond milling. UPDM (Ultra-precision diamond milling) have the advantage with no tool interference problem in comparison with tool servo machining techniques. In this paper, the tool setting error compensation method and the tool path of UPDM has been developed for the fabrication of a 5 by 5 AMLA model. The form accuracy and surface roughness of each lenses of the AMLA was less than 0.2μm and 5nm, respectively. And the pitch error of each micro lens was less than 2μm in 25 micro lenses.

  18. From Spheric to Aspheric Solid Polymer Lenses: A Review

    Directory of Open Access Journals (Sweden)

    Kuo-Yung Hung

    2011-01-01

    Full Text Available This paper presents a new approach in the use of MEMS technology to fabricate micro-optofluidic polymer solid lenses in order to achieve the desired profile, focal length, numerical aperture, and spot size. The resulting polymer solid lenses can be applied in optical data storage systems, imaging systems, and automated optical inspection systems. In order to meet the various needs of different applications, polymer solid lenses may have a spherical or aspherical shape. The method of fabricating polymer solid lenses is different from methods used to fabricate tunable lenses with variable focal length or needing an external control system to change the lens geometry. The current trend in polymer solid lenses is toward the fabrication of microlenses with a high numerical aperture, small clear aperture (<2 mm, and high transmittance. In this paper we focus on the use of thermal energy and electrostatic force in shaping the lens profile, including both spherical and aspherical lenses. In addition, the paper discusses how to fabricate a lens with a high numerical aperture of 0.6 using MEMS and also compares the optical characteristics of polymer lens materials, including SU-8, Norland Optical Adhesive (NOA, and cyclic olefin copolymer (COC. Finally, new concepts and applications related to micro-optofluidic lenses and polymer materials are also discussed.

  19. System and Method for Null-Lens Wavefront Sensing

    Science.gov (United States)

    Hill, Peter C. (Inventor); Thompson, Patrick L. (Inventor); Aronstein, David L. (Inventor); Bolcar, Matthew R. (Inventor); Smith, Jeffrey S. (Inventor)

    2015-01-01

    A method of measuring aberrations in a null-lens including assembly and alignment aberrations. The null-lens may be used for measuring aberrations in an aspheric optic with the null-lens. Light propagates from the aspheric optic location through the null-lens, while sweeping a detector through the null-lens focal plane. Image data being is collected at locations about said focal plane. Light is simulated propagating to the collection locations for each collected image. Null-lens aberrations may extracted, e.g., applying image-based wavefront-sensing to collected images and simulation results. The null-lens aberrations improve accuracy in measuring aspheric optic aberrations.

  20. Non-rotational aspherical models of the human optical system

    Science.gov (United States)

    Giovanzana, S.; Kasprzak, H. T.; Pałucki, B.; Ţălu, Ş.

    2013-12-01

    The aim of this work was to define three-dimensional (3D) non-rotational aspherical parametric models for the human cornea and lens using computational geometry and CAD representations. The hyperbolic cosine based function is used for the cornea and a parametric model is used for lens modeling. Data analysis and visualization of 3D non-rotational models were made using the Rhinoceros CAD software and MATLAB software was used for numeric computation. We combined, implemented, and evaluated these models with a 3D ray-tracing in order to fully analyze the human eye model. It was found that 3D non-rotational aspherical models for the human eye could be more accurately modeled and rendered for analysis with finite element method. The objective of this study is to present and analyze mathematical models of the cornea and lens and to highlight the potential of optical applications of the eye models containing astigmatic surfaces, which are more close to the real eye than spherosymmetric eye models.

  1. Optical receiving system based on a compound parabolic concentrator and a hemispherical lens for visible light communication.

    Science.gov (United States)

    Wang, Yun; Lan, Tian; Ni, Guoqiang

    2016-12-20

    We propose a scheme for designing a new optical receiving system that can reduce the received-energy spot size via integration of a compound parabolic concentrator with a hemispherical lens. SolidWorks is used to model the receiving system, while TracePro is employed for simulations. The field of view is set to 30° and the radius of the compound parabolic concentrator outlet is 5 mm, which is also the radius of the hemispherical lens. Ray-tracing results show that under the given simulation conditions, the radius of the spot area is reduced from 5 to 3 mm at the receiving system and the gain is 5.2. In regard to the relations between received power and the radius of the hemispherical lens R, and the received power and the distance d between the compound parabolic concentrator and hemispherical lens, our detailed analysis yields the following characteristics: (1) the received power increases as R increases, but decreases as d increases; (2) as R increases, the spot area increases and the received flux is dispersed over the receiving plane, which dispersion is disadvantageous for high-speed communication; (3) the gain of the receiving system also varies with R and d; (4) an increase in d leads to decrease in the received flux and gain when d>-2  mm. Based on these characteristics, we set R=5  mm and calculate the energy efficiency. We obtain maximum energy efficiencies for different detection areas.

  2. GANAS: A HYBRID ANASTIGMATIC ASPHERICAL PRIME-FOCUS CORRECTOR

    Directory of Open Access Journals (Sweden)

    F. Della Prugna

    2009-01-01

    Full Text Available The Cassegrain-Coud 1 meter Car to the focal plane of the primary f/5 l Zeiss telescope at the Venezuelan National Astronomical Observatory uses six optical elements. Removal of the secondary convex mirror gives accessspheroidal mirror, but spherical aberration, coma, astigmatism and eld curvature severely hamper its imaging capabilities. In order to carry out prime-focus imaging, we designed and manufactured a corrector group, called GAnAs, to minimize these aberrations over a circular eld of 300. The corrector group is a hybrid con guration with two thin aspherical 4th-order plates and a meniscus lens.

  3. 非球面晶状体与传统球面晶状体植入术后对比敏感度的研究%Contrast sensitivity of aspheric and standard spherical intraocular lens after phacoemulsification

    Institute of Scientific and Technical Information of China (English)

    徐仁凤; 王理理; 黄振平; 吴勇

    2007-01-01

    目的:比较白内障术后早期非球面晶状体与传统球面晶状体植入术后功能视力.方法:白内障患者共50例,随机分成两组,一组患者植入以Acrysof IQ(Alcon)为代表的非球面晶状体,共23例 23眼;一组植入以AR40e(AMO)为代表的传统球面晶状体,共27例27眼.于术后1mo用CSV-1000E对比敏感度测试仪(由VECTOR VISION 公司提供)进行对比敏感度测定.结果:以Acrysof IQ (Alcon)为代表的非球面晶状体在6.12.18cpd时较以AR40e(AMO)为代表的传统球面晶状体能显著的提高患者对比敏感度.结论:以Acrysof IQ(Alcon)为代表的非球面晶状体可提高患者的功能视力%AIM:To compare the contrast sensitivity obtained through anterior surface modified prolate intraocular lens with the contrast sensitivity obtained through standard spherical intraocular Iens.METHODS:Patients presenting for cataract surgery in one eye were randomized to receive either the Acrysef IQ intraocular lens(AIcon)or the AR40e intraocular lens(AMO).50 eyes after phacoemulsification with IOL implantation were included,23 eyes received Acrysof IQ,and 27 eyes received AP40e intraocular lens (AMO).Contrast sensitivity testing under photopic conditions (85cd/m2)served as the prindpal outcome measure.The contrast sensitivity function was measured with CSV-1000E Vision Testing Instrument(provided by VECTOR ⅥSION COMPANY) at 30 days after surgery.RESULTS:The Acrysof IQ intraocular lens provided statistically significantly better contrast sensitivity at 6,12 and 18 cydes per degree under photopic conditions.CONCLUSION:The use of anterior surface modified prolate intraocular lens for cataract surgery has the potential to improve functional vision.

  4. Effect of tilt and decentration of intraocular lens asphericity on visual quality%不同人工晶状体植入术后倾斜和偏心及视觉质量的临床研究

    Institute of Scientific and Technical Information of China (English)

    王莹; 马忠旭; 刘汝瑜; 张伟

    2011-01-01

    Objective: To analyze the effect of tilt and decentration of intraocular lenses (IOLs) asphericity on visual quality after pha-coemulsification surgery and IOLs implantation. Methods: It was a prospective clinical study. A total of 85 eyes of 69 patients with IOLs implantation and 3 to 4 months after surgery were analyzed in this study, including 30 eyes with spherical IOL of Sensar AR40e, 25 eyes with aspherically neutral IOL of Softec HD and 30 eyes aspheric IOL of Tecnis ZA9003 with negative spherical aberration. At postoperat ive follow-up visits, higher-order aberrations (HOAs) and modulation transfer function(MTF) at six spatial frequencies (5,10,15,20,25,30cpd) were measured in 5.0 mm pupil size. Tilt and decentration of the IOLs were measured using Scheimpflug photography(Pentacam ,0culus). The tilt and decentration, HOAs and subtracted lower order aberration MTF( MTF(HOA) )were compared. The effect of tilt and decentration on HOAs and MTF(HOA)was assessed using multiple regression analysis. Results: No significant differences in IOL tilt or decentration were found(F=0.001, F=0.050;P=0.999, ,P=0.952).The spherical aberration in AR40e group was largest and the differences were statistically significant(F= 65.68, P=0.000). In 5.0 mm pupil size,MTF(HOA)at all spatial frequencies in AR40e group were lowest and the differ ences were statistically significant(P<0.05). Tilt and decentration did not significantly affect HOAs and MTF(HOA)- Conclusion: The amounts of tilt and decentration of both IOLs are not large enough to affect the correction of spherical aberration and cause deterioration of visual quality.%目的:研究白内障超声乳化吸除术植入不同球差人工晶状体(IOL)的倾斜和偏心对高阶像差(HOAs)和调制传递函数(MTF)的影响.方法:前瞻性研究.选取老年性白内障患者69例(85只眼),随机分成3组,25例(30只眼)植入球面IOL Sensar AR40e,19例(25只眼)植入零球差IOL Softec HD,30

  5. ELID Grinding of Large Aspheric Optics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Large aperture aspheric optics are among the most susceptible optical surfaces to the accumulation of periodic surface artifacts during fabrication. Periodic...

  6. Effect of tilt and decentration of spherical and aspheric intraocular lens on visual quality%球面和非球面人工晶状体倾斜和偏心对视觉质量的影响

    Institute of Scientific and Technical Information of China (English)

    张伟; 马忠旭; 刘汝瑜; 张玲

    2010-01-01

    目的 研究超声乳化白内障吸除术后球面和非球面人工晶状体(intraocularlens,IOL)的倾斜和偏心及其对高阶像差(higher-order aberrations,HOAs)和视觉质量的影响.方法 前瞻性研究.取50例单纯性老年性白内障患者60只眼,30只眼随机植入AMO公司的球面IOLSensar AR40e,30只眼植入非球面IOLTecnisZA9003.术后3到4个月,检测患者在5.0mm瞳孔下的HOAs以及5、10、15、20、25、30周每度(cycles per degree,cpd)空间频率下的调制传递函数(modulation transfer function,MTF).通过Scheimpflug像,测量IOL的倾斜与偏心.比较两组间倾斜度和偏心值、HOAs及各空间频率下去除低阶像差的MTF(MTF(HOA))值.使用多元回归分析来确定倾斜和偏心对HOAs和视觉质量的影响.结果 光学部倾斜AR40e组(2.99±0.94)°,ZA9003组(2.98±1.15)°.光学部偏心AR40e组(0.30±0.13)mm,ZA9003组(0.31±0.14)mm.组间倾斜和偏心差异无统计学意义(Z=-0.044,-0.525,P=0.965,0.600,Mann-WhitneyU检验).总4阶球差,AR40e组(0.366±0.163)μm大于ZA9003组(0.027±0.072)μm,差异有统计学意义(t=-10.386,P=0.000).ZA9003组在5.0mm瞳孔直径下各频段的MTF(HOA)值均高于AR40e组,有统计学意义(P<0.05).两组IOL倾斜和偏心对各自的HOAs及各频段的MTF(HOA)值均无明显影响.结论 当IOL的倾斜和偏心在正常限度内时,不会危害非球面IOL对球差的补偿作用,不足以导致视觉质量的下降.%Objective To study tilt and decentration of spherical and aspheric IOL implantation after phacoemulsification surgery and effect on higher-order aberrations (HOAs) and visual quality. Methods It was a prospective clinical study. A total of 60 eyes (50 patients) were divided into 2 groups randomly, of 30 eyes in each group, one group with Sensar AR40e (AMO), one group with Tecnis ZA9003 (AMO). Three to four months after surgery, higher-order aberrations (HOAs) and modulation transfer function (MTF) at six spatial frequencies (5, 10, 15, 20

  7. Research on testing method for combined aspheric surface with non-rotational symmetric

    Science.gov (United States)

    Zhou, Wencai; Xu, Feng; Wei, Xiaoxiao

    2016-09-01

    Non-rotational symmetric aspheric surface has many significant advantages, but it still can not be widely used because the limiting that there is no method can tests it precisely. At present, the coordinate contour measuring machine is the main testing method for the aspheric surface with non-rotational symmetric, but the measurement accuracy of this method is not high. In this paper, the method of diffraction compensator (computed graphic holograph) has been adopted to test the combined aspheric surface, which can compensate the phase caused by tested lens. The sample surface is the combined aspheric surface with diameter of 33.84mm, and the process from optical software simulation design, the fabrication of the computed graphic holograph (CGH) to experimental platform built is given in detail after testing via the CGH technology. The simulation results show that the root mean square (RMS) of remnant wave-front error is 0.004 λ, and the peak to valley (PV) is 0.0245 λ. The free-from surface has been tested by Zygo interferometer, and the experimental results show that the RMS is 0.49 λ, the PV is 4.69 λ. The accuracy of the result is higher than that of coordinate contour measuring machine. The system error caused by optical elements analysed is 0.1149λ. The accurate result means that the CGH technology for testing the combined aspheric surface is realized.

  8. Extended formalism for simulating compound refractive lens-based x-ray microscopes

    CERN Document Server

    Simons, Hugh; Poulsen, Henning Friis; Detlefs, Carsten

    2016-01-01

    We present a comprehensive formalism for the simulation and optimisation of CRLs in both condensing and full-field imaging configurations. The approach extends ray transfer matrix analysis to account for x-ray attenuation by the lens material. Closed analytical expressions for critical imaging parameters such as numerical aperture, vignetting, chromatic aberration and focal length are provided for both thin- and thick-lens imaging geometries.

  9. New Physical Optics Method for Curvilinear Refractive Surfaces and its Verification in the Design and Testing of W-band Dual-Aspheric Lenses

    Science.gov (United States)

    2013-10-01

    aspheric ( plano -convex) and (b) optimized dual- aspheric W-band PTFE lenses as needed for a non-paraxial system of Fig. 1 . . 10 3 Profiles of (a) full...is comparable with the given lens diameter Dc = 140mm. Following conventional solutions, non-paraxial lenses of plano -convex type are usually em...optimized by applying more advanced methods, e.g., full-wave approaches, etc. When considering plano -convex lenses by ray-tracing methods, we arrive at

  10. Method to design two aspheric surfaces for a wide field of view imaging system with low distortion.

    Science.gov (United States)

    Bian, Yinxu; Li, Haifeng; Wang, Yifan; Zheng, Zhenrong; Liu, Xu

    2015-09-20

    This paper presents a distortion correction method for designing a wide field of view (FOV) lens for an imaging system. The lens is composed of two aspheric surfaces and several spheres. In the preliminary design, profiles of the aspheric surfaces can be obtained according to aplanatism, refraction law, and polynomial fitting methods, where the numeric computation, the differential geometry computation, and the polynomial fitting algorithm are stated in detail. Then the lens is optimized by the damped least squares method. Theoretically, this method cannot eliminate aberrations absolutely but can balance some kinds of aberrations to the image well. Furthermore, a projector lens with a wide FOV, low distortion, and low throw ratio [TR = (projection distance)/(image diagonal size)] is designed successfully by this method.

  11. Study on optical fabrication and metrology of precise convex aspheric mirror

    Science.gov (United States)

    Wang, Huijun; Xu, Jin; Wang, Peng; Li, Ang; Guo, Wen; Du, Yan

    2016-10-01

    Optical fabrication and metrology technologies are studied in the paper to improve the accuracy of surface figure of a convex aspheric mirror. First, the main specifications of a convex aspheric mirror which is chosen to be the secondary mirror of an optical system are presented. The aperture of the mirror is 400mm. The mirror is made of ultra-low expansion (ULE) glass with honeycomb sandwich structure to get the ideal lightweight requirement. Then the mirror is surfaced by ultrasonic grinding, smart robot lapping and smart robot polishing processes relatively. Large-apertured tool is applied to reduce the mid-frequency surface error. Both the contour measuring method in the grinding and lapping stage and the measuring method with meniscus lens and its calibration mirror in the polishing stage are studied. The final surface figure of the mirror is that the root mean-square value (RMS value) is 0.016λ (λ=632.8nm), which meets the requirement of the optical system. The results show that the forging surfacing processes and measuring methods are accurate and efficient to fabricate the convex aspheric mirror and can be applied in optical fabrication for larger-apertured convex aspheric mirrors.

  12. Effect of germination time on proximate analysis, bioactive compounds and antioxidant activity of lentil (Lens culinaris Medik. sprouts

    Directory of Open Access Journals (Sweden)

    A. Ahmed Fouad

    2015-09-01

    Full Text Available Background. The lentil plant, Lens culinaris L., is a member of the Leguminoceae family and constitutes one of the most important traditional dietary components. The purpose of the current study was to investigate the effects of sprouting for 3, 4, 5 and 6 days on proximate, bioactive compounds and antioxidative characteristics of lentil (Lens culinaris sprouts. Material and methods. Lentil seeds were soaked in distilled water (1:10, w/v for 12 h at room temperature (~25°C, then kept between thick layers of cotton cloth and allowed to germinate in the dark for 3, 4, 5 and 6 days. The nutritional composition, protein solubility, free amino acids, antinutritional factors, bioactive compounds and antioxidant activity of raw and germinated samples were determined using standard official procedures. Results. Sprouting process caused significant (P ≤ 0.05 increases in moisture, protein, ash, crude fiber, protein solubility, free amino acids, total, reducing and nonreducing sugars. However, oil content, antinutritional factors (tannins and phytic acid significantly (P ≤ 0.05 decreased. Results indicated that total essential amino acids of lentil seeds protein formed 38.10% of the total amino acid content. Sulfur-containing amino acids were the first limiting amino acid, while threonine was the second limiting amino acid in raw and germinated lentil seeds. Sprouting process has a positive effect on the essential amino acid contents and protein efficiency ratio (PER of lentil sprouts. Phenolics content increased from 1341.13 mg/100 g DW in raw lentil seeds to 1411.50, 1463.00, 1630.20 and 1510.10 in those samples germinated for 3, 4, 5 and 6 days, respectively. Sprouted seeds had higher DPPH radical scavenging and reducing power activities. Conclusions. Based on these results, sprouting process is recommended to increase nutritive value, and antioxidant activity of lentil seeds.

  13. Annular sub-aperture stitching interferometry testing for large-caliber aspheric

    Science.gov (United States)

    Wu, Pengfei; Yang, Shuming; Sun, Lin; Zhao, Pu; Jiang, Zhuangde

    2016-09-01

    An annular sub-aperture stitching interferometry testing is proposed for large-caliber aspheric lens testing, expanding the dynamic range of the interferometer, broadening the scope of the measurement, and reducing the cost of the measurement to a large extent without the use of compensating elements. The large-caliber aspheric is divided into several annular sub-apertures, and there are some overlapping areas between each two adjacent sub-apertures. When testing, the test aspheric is moved along the optical axis according to path planning so that the reference spherical shape and the test aspheric interest at points of common tangency to reduce the fringe density of the sub-aperture. However, in the process of moving the test optic, six DOF (degrees of freedom) misalignment errors will occur. According to the rigid body kinematics theory, the misalignment error separation model is established so that the misalignment factors can be calculated by the information of each overlapping regions. Then all sub-apertures are unified to the same reference with proper algorithm, and subsequently, misalignment error of the reference is removed by Zernike polynomial fitting, and the whole surface error is recovered. Simulation results are shown to demonstrate the feasibility of the method we developed. By analyzing the influence of the six DOF on the stitching result, the most important factor is obtained, and some measures are taken, that is, a measurement system combining two interferometers is designed, one of which is to measure the departures between the reference and the aspheric, and another to test the piston errors to be transmitted to the control system to improve the accuracy.

  14. Profiling of aspherical surfaces using moire deflectometry

    Science.gov (United States)

    Uitterdijk, T.; Frankena, Hans J.; Smorenburg, Kees

    1994-11-01

    An elegant measuring setup for contouring strong aspherical surfaces is introduced. Moire deflectometry is chosen as the measuring method because the configuration is simple, robust, and variable in sensitivity. The instrument is capable of measuring height deviations between an aspherical surface and its best fitting sphere ranging from minimally 1 micrometers to maximally 30 micrometers with a relative accuracy of 10%, which is useful for the production of surfaces in infrared optics. It is possible to measure transparent as well as reflecting surfaces, both convex and concave. A CCD-camera and a PC make part of the setup to automate the measurements. The short measurement time of less than 60 seconds makes the instrument useful in the manual production of aspherical surfaces.

  15. [Lens platform].

    Science.gov (United States)

    Łukaszewska-Smyk, Agnieszka; Kałuzny, Józef

    2010-01-01

    The lens platform defines lens structure and lens material. Evolution of lens comprises change in their shape, angulation of haptens and transition of three-piece lens into one-piece lens. The lens fall into two categories: rigid (PMMA) and soft (siliconic, acrylic, colameric). The main lens maaterials are polymers (hydrophilic and hydrophobic). The lens platform has an effect on biocompatibility, bioadhesion, stability of lens in capsule, degree of PCO evolution and sensitiveness to laser damages.

  16. Aspheric surface testing by irradiance transport equation

    Science.gov (United States)

    Shomali, Ramin; Darudi, Ahmad; Nasiri, Sadollah; Asgharsharghi Bonab, Armir

    2010-10-01

    In this paper a method for aspheric surface testing is presented. The method is based on solving the Irradiance Transport Equation (ITE).The accuracy of ITE normally depends on the amount of the pick to valley of the phase distribution. This subject is investigated by a simulation procedure.

  17. In vivo human crystalline lens topography.

    Science.gov (United States)

    Ortiz, Sergio; Pérez-Merino, Pablo; Gambra, Enrique; de Castro, Alberto; Marcos, Susana

    2012-10-01

    Custom high-resolution high-speed anterior segment spectral domain optical coherence tomography (OCT) was used to characterize three-dimensionally (3-D) the human crystalline lens in vivo. The system was provided with custom algorithms for denoising and segmentation of the images, as well as for fan (scanning) and optical (refraction) distortion correction, to provide fully quantitative images of the anterior and posterior crystalline lens surfaces. The method was tested on an artificial eye with known surfaces geometry and on a human lens in vitro, and demonstrated on three human lenses in vivo. Not correcting for distortion overestimated the anterior lens radius by 25% and the posterior lens radius by more than 65%. In vivo lens surfaces were fitted by biconicoids and Zernike polynomials after distortion correction. The anterior lens radii of curvature ranged from 10.27 to 14.14 mm, and the posterior lens radii of curvature ranged from 6.12 to 7.54 mm. Surface asphericities ranged from -0.04 to -1.96. The lens surfaces were well fitted by quadrics (with variation smaller than 2%, for 5-mm pupils), with low amounts of high order terms. Surface lens astigmatism was significant, with the anterior lens typically showing horizontal astigmatism ([Formula: see text] ranging from -11 to -1 µm) and the posterior lens showing vertical astigmatism ([Formula: see text] ranging from 6 to 10 µm).

  18. Asphericity in supernova explosions from late-time spectroscopy.

    Science.gov (United States)

    Maeda, Keiichi; Kawabata, Koji; Mazzali, Paolo A; Tanaka, Masaomi; Valenti, Stefano; Nomoto, Ken'ichi; Hattori, Takashi; Deng, Jinsong; Pian, Elena; Taubenberger, Stefan; Iye, Masanori; Matheson, Thomas; Filippenko, Alexei V; Aoki, Kentaro; Kosugi, George; Ohyama, Youichi; Sasaki, Toshiyuki; Takata, Tadafumi

    2008-02-29

    Core-collapse supernovae (CC-SNe) are the explosions that announce the death of massive stars. Some CC-SNe are linked to long-duration gamma-ray bursts (GRBs) and are highly aspherical. One important question is to what extent asphericity is common to all CC-SNe. Here we present late-time spectra for a number of CC-SNe from stripped-envelope stars and use them to explore any asphericity generated in the inner part of the exploding star, near the site of collapse. A range of oxygen emission-line profiles is observed, including a high incidence of double-peaked profiles, a distinct signature of an aspherical explosion. Our results suggest that all CC-SNe from stripped-envelope stars are aspherical explosions and that SNe accompanied by GRBs exhibit the highest degree of asphericity.

  19. Softec HD hydrophilic acrylic intraocular lens: biocompatibility and precision

    OpenAIRE

    Ladan Espandar; Shameema Sikder; Majid Moshirfar

    2011-01-01

    Ladan Espandar1, Shameema Sikder2, Majid Moshirfar31Department of Ophthalmology, Tulane University, New Orleans, LA, USA; 2Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA; 3John A Moran Eye Center, University of Utah, Salt Lake City, UT, USAAbstract: Intraocular lens development is driven by higher patient expectations for ideal visual outcomes. The recently US Food and Drug Administration-approved Softec HD™ lens is an aspheric, hydrophilic acrylic intraocular le...

  20. Patient acceptability of the Tecnis® multifocal intraocular lens

    OpenAIRE

    Woodward, Maria; Sood,Priyanka

    2011-01-01

    Priyanka Sood1, Maria A Woodward21Emory Eye Center, Atlanta, GA, USA; 2Kellogg Eye Center, Ann Arbor, MI, USAAbstract: Cataract surgery has evolved. The goal of the surgeon includes both restoration of vision and refinement of vision. Patients' desire for spectacle independence has driven the market for presbyopia-correcting cataract surgery and development of novel intraocular lens (IOL) designs. The Tecnis® Multifocal Intraocular Lens incorporates an aspheric, modified anter...

  1. Asphericity analysis using corneal wavefront and topographic meridional fits

    Science.gov (United States)

    Arba-Mosquera, Samuel; Merayo-Lloves, Jesús; de Ortueta, Diego

    2010-03-01

    The calculation of corneal asphericity as a 3-D fit renders more accurate results when it is based on the corneal wavefront aberrations rather than on the corneal topography of the principal meridians. A more accurate prediction could be obtained for hyperopic treatments compared to myopic treatments. We evaluate a method to calculate corneal asphericity and asphericity changes after refractive surgery. Sixty eyes of 15 consecutive myopic patients and 15 consecutive hyperopic patients (n=30 each) are retrospectively evaluated. Preoperative and 3-month-postoperative topographic and corneal wavefront analyses are performed using corneal topography. Ablations are performed using a laser with an aberration-free profile. Topographic changes in asphericity and corneal aberrations are evaluated for a 6-mm corneal diameter. The induction of corneal spherical aberrations and asphericity changes correlates with the achieved defocus correction. Preoperatively as well as postoperatively, asphericity calculated from the topography meridians correlates with asphericity calculated from the corneal wavefront in myopic and hyperopic treatments. A stronger correlation between postoperative asphericity and the ideally expected/predicted asphericity is obtained based on aberration-free assumptions calculated from corneal wavefront values rather than from the meridians. In hyperopic treatments, a better correlation can be obtained compared to the correlation in myopic treatments. Corneal asphericity calculated from corneal wavefront aberrations represents a 3-D fit of the corneal surface; asphericity calculated from the main topographic meridians represents a 2-D fit of the principal corneal meridians. Postoperative corneal asphericity can be calculated from corneal wavefront aberrations with higher fidelity than from corneal topography of the principal meridians. Hyperopic treatments show a greater accuracy than myopic treatments.

  2. ASPHERICITY AND PROLATENESS OF LINEAR AND CIRCULAR MACROMOLECULES

    Institute of Scientific and Technical Information of China (English)

    WEI Gaoyuan

    1995-01-01

    The shape asymmetry of gaussian models of linear and circular macromolecules has been numerically invesigated in terms of asphericity and prolateness parameters. These parameters are found to decrease with increasing length for the macromolecule either confined to a plane or in three dimensions. The effect of dimensionality on these parameters is visible only for low dimensions and is generally weak. As dimensionality goes to infinity, it is found that asphericity and prolateness for both chains and rings approach slowly yet descendingly values of corresponding asphericity and prolateness factors, with the exception of the chain which shows a minimum value of asphericity when the embedding space has a dimensionality of four.

  3. Research on CNC Turning System of Aspheric Machining Grinding Wheel

    Institute of Scientific and Technical Information of China (English)

    ZOU Qin; GUO Yin-biao

    2005-01-01

    The technology of machining aspheric surface with high precision is the premise for the application of aspheric surface. The grinding machining with error compensation is a commonly used method to machine aspheric surface, which will directly influence the quality of aspheric workpiece surface. Multifunctional CNC grinding wheel truing system is a four-axis CNC truing system which can be applied to grinding wheel truing. In this system,DSP-based multi-axes motion control card is adopted as the controller, and visual C++ is used as development tool.When the design of hardware and software is completed, the system can implement truing of various grinding wheel with high precision aspheric machining such as plane grinding wheel, arc grinding one, and sphere grinding one.

  4. Qualification of a Null Lens Using Image-Based Phase Retrieval

    Science.gov (United States)

    Bolcar, Matthew R.; Aronstein, David L.; Hill, Peter C.; Smith, J. Scott; Zielinski, Thomas P.

    2012-01-01

    In measuring the figure error of an aspheric optic using a null lens, the wavefront contribution from the null lens must be independently and accurately characterized in order to isolate the optical performance of the aspheric optic alone. Various techniques can be used to characterize such a null lens, including interferometry, profilometry and image-based methods. Only image-based methods, such as phase retrieval, can measure the null-lens wavefront in situ - in single-pass, and at the same conjugates and in the same alignment state in which the null lens will ultimately be used - with no additional optical components. Due to the intended purpose of a Dull lens (e.g., to null a large aspheric wavefront with a near-equal-but-opposite spherical wavefront), characterizing a null-lens wavefront presents several challenges to image-based phase retrieval: Large wavefront slopes and high-dynamic-range data decrease the capture range of phase-retrieval algorithms, increase the requirements on the fidelity of the forward model of the optical system, and make it difficult to extract diagnostic information (e.g., the system F/#) from the image data. In this paper, we present a study of these effects on phase-retrieval algorithms in the context of a null lens used in component development for the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission. Approaches for mitigation are also discussed.

  5. 计算全息法检测离轴凸非球面照明镜组初始结构设计%Design of Original Structure of Illuminating System in Off-Axis Convex Aspherical Lens Testing System with Computer-Generated Hologram

    Institute of Scientific and Technical Information of China (English)

    任建锋; 郭培基

    2012-01-01

    A special illuminating system is proposed and designed in order to accurately test convex off-axis aspherical mirrors with computer-generated holograms (CGH). Illuminating system is used as reference system and used to project testing beam on under-testing aspherical mirrors vertically and also makes testing beam and reference beam near common-path. The geometrical system of this illuminating system is introduced and analysed. Then the relation of characters of work distance, focal length and the curvature radius of reference surface of illuminating system is obtained after simplify this multipurpose system to simple model system. The initial system can be realized by controlling these characteristic parameters as merit function during optical design process. Design results show that this method can satisfy requirement of system use.%设计一种特殊的应用于计算全息法(CGH)高精度检测离轴凸非球面系统的照明系统.该照明系统一方面用作参考系统,另一方面将检测光近似垂直投射到待检测镜面上,使得检测系统为近似共光路系统,降低照明系统的制造精度.分析了照明系统的几何光路模型,将复杂的两用途系统简化,得到照明系统工作距离、照明系统焦距以及参考面曲率半径三个特征参量之间的关系.设计时,通过控制这几个特征参量,得到满足检测要求的系统初始结构.设计结果表明,该方法可以满足系统使用要求.

  6. Mechanically tunable aspheric lenses via additive manufacture of hanging elastomeric droplets for microscopic applications

    Science.gov (United States)

    Fuh, Yiin-Kuen; Chen, Pin-Wen; Lai, Zheng-Hong

    2016-07-01

    Mechanically deformable lenses with dynamically tunable focal lengths have been developed in this work. The fabricated five types of aspheric polydimethylsiloxane (PDMS) lenses presented here have an initial focal length of 7.0, 7.8, 9.0, 10.0 and 10.2 mm. Incorporating two modes of operation in biconvex and concave-convex configurations, the focal lengths can be tuned dynamically as 5.2-10.2, 5.5-9.9, 6.6-11.9, 6.1-13.5 and 6.6-13.5 mm respectively. Additive manufacturing was utilized to fabricate these five types of aspheric lenses (APLs) via sequential layering of PDMS materials. Complex structures with three-dimensional features and shorter focal lengths can be successfully produced by repeatedly depositing, inverting and curing controlled PDMS volume onto previously cured PDMS droplets. From our experiments, we empirically found a direct dependence of the focal length of the lenses with the amount (volume) of deposited PDMS droplets. This new mouldless, low-cost, and flexible lens fabrication method is able to transform an ordinary commercial smartphone camera into a low-cost portable microscope. A few microscopic features can be readily visualized, such as wrinkles of ladybird pupa and printed circuit board. The fabrication technique by successively applying hanging droplet and facile mechanical focal-length-tuning set-up can be easily adopted in the development of high-performance optical lenses.

  7. A fast processing route of aspheric polydimethylsiloxane lenses array (APLA) and optical characterization for smartphone microscopy

    Science.gov (United States)

    Fuh, Yiin-Kuen; Lai, Zheng-Hong

    2017-02-01

    A fast processing route of aspheric polydimethylsiloxane (PDMS) lenses array (APLA) is proposed via the combined effect of inverted gravitational and heat-assisted forces. The fabrication time can be dramatically reduced to 30 s, compared favorably to the traditional duration of 2 hours of repeated cycles of addition-curing processes. In this paper, a low-cost flexible lens can be fabricated by repeatedly depositing, inverting, curing a hanging transparent PDMS elastomer droplet on a previously deposited curved structure. Complex structures with aspheric curve features and various focal lengths can be successfully produced and the fabricated 4 types of APLA have various focal lengths in the range of 7.03 mm, 6.00 mm, 5.33 mm, and 4.43 mm, respectively. Empirically, a direct relationship between the PDMS volume and focal lengths of the lenses can be experimentally deducted. Using these fabricated APLA, an ordinary commercial smartphone camera can be easily transformed to a low-cost, portable digital microscopy (50×magnification) such that point of care diagnostic can be implemented pervasively.

  8. Error analysis of aspheric surface with reference datum.

    Science.gov (United States)

    Peng, Yanglin; Dai, Yifan; Chen, Shanyong; Song, Ci; Shi, Feng

    2015-07-20

    Severe requirements of location tolerance provide new challenges for optical component measurement, evaluation, and manufacture. Form error, location error, and the relationship between form error and location error need to be analyzed together during error analysis of aspheric surface with reference datum. Based on the least-squares optimization method, we develop a least-squares local optimization method to evaluate form error of aspheric surface with reference datum, and then calculate the location error. According to the error analysis of a machined aspheric surface, the relationship between form error and location error is revealed, and the influence on the machining process is stated. In different radius and aperture of aspheric surface, the change laws are simulated by superimposing normally distributed random noise on an ideal surface. It establishes linkages between machining and error analysis, and provides an effective guideline for error correcting.

  9. An Instrument for Inspecting Aspheric Optical Surfaces and Components Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a Phase II SBIR proposal to develop an extremely versatile optical inspection tool for aspheric optical components and optics that are not easily inspected...

  10. An Instrument for Inspecting Aspheric Optical Surfaces and Components Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a Phase I proposal to develop an extremely versatile optical inspection tool for determining the optical figure of aspheric optical components, such as test...

  11. ASPHERICAL SURFACES APPROXIMATION IN AUTOMATED DESIGN OF OPTICAL SYSTEMS

    Directory of Open Access Journals (Sweden)

    T. V. Ivanova

    2015-07-01

    Full Text Available Subject of Research. The paper deals with the problems of higher order aspherical surfaces approximation using different equation types. The objects of research are two types of equations for higher order aspherical surfaces description used in different software for optical systems design (SАRО, OPAL, ZEMAX, CODE-V, etc. and dependent on z-coordinate or on a radial coordinate on the surface. Conversion from one type of equations to another is considered in view of application in different software for optical systems design. Methods. The subject matter of the method lies in usage of mean square method approximation for recalculation of high-order aspherical surface. Iterative algorithm for recalculation is presented giving the possibility to recalculate coefficients for different types of equations with required accuracy. Recommendations are given for choosing recalculation parameters such as the number of result equation coefficients, the number of points for recalculation and point allocation on a surface. Main Results. Example of recalculation for aspherical surface and accuracy estimation, including result aberration comparison between initial surface and recalculated surface are presented. The example has shown that required accuracy of surface representation was obtained. Practical Relevance. This technique is usable for recalculation of higher order aspherical surfaces in various types of software for optical systems design and also for research of optimal higher order aspherical surfaces description.

  12. Patient acceptability of the Tecnis® multifocal intraocular lens

    Directory of Open Access Journals (Sweden)

    Sood P

    2011-03-01

    Full Text Available Priyanka Sood1, Maria A Woodward21Emory Eye Center, Atlanta, GA, USA; 2Kellogg Eye Center, Ann Arbor, MI, USAAbstract: Cataract surgery has evolved. The goal of the surgeon includes both restoration of vision and refinement of vision. Patients' desire for spectacle independence has driven the market for presbyopia-correcting cataract surgery and development of novel intraocular lens (IOL designs. The Tecnis® Multifocal Intraocular Lens incorporates an aspheric, modified anterior prolate IOL with a diffractive multifocal lens design. The design aims to minimize spherical aberration and improve range of focus. The purpose of this review is to assess patient acceptability of the Tecnis® multifocal intraocular lens.Keywords: Tecnis®, intraocular lens, multifocal, presbyopia 

  13. Effect of crystalline lens surfaces and refractive index on image quality by model simulation analysis

    Institute of Scientific and Technical Information of China (English)

    Meimei Kong; Zhishan Gao; Lei Chen; Xinhua Li

    2008-01-01

    The surfaces and refractive index of crystalline lens play an important role in the optical performance of human eye.On the basis of two eye models,which are widely applied at present,the effect of lens surfaces and its refractive index distribution on optical imaging is analyzed with the optical design software ZEMAX (Zemax Development Co.,San Diego,USA).The result shows that good image quality can be provided by the aspheric lens surfaces or (and) the gradient-index (GRIN) distribution.It has great potential in the design of intraocular lens (IOL).The eye models with an intraocular implantation are presented.

  14. Ultraprecision machining of steep aspheric parts with large sagittal height

    Science.gov (United States)

    Mu, Lin; Zhao, Rui; Xin, Qiming

    2009-05-01

    Problems occurred during machining steep aspheric parts with large sagittal height on double-spindle diamond turning machine are presented and the main reasons of the problems are described. And methods of solving these problems are also suggested. When we machine steep aspheric parts with large sagittal height on a 2 axis diamond turning machine, we have such problems as difficult control of part edge accuracy, poor roughness and rapid wear of the cutting tool. The main reasons for these problems lie in: 1) Measurement. To make accurate measurements, the measurement range of the profilometer must fall within the sagittal heights of the aspheric parts, and the measurement angle must also meet the requirements, an insufficient measurement angle, for example, will have a big impact on the measurement and fabrication accuracy of such parts; and 2) Machine and tool, firstly, the diamond cutting tool will suffer a very big force when turning the edge section, resulting in bigger micro-vibration in the tool and tool post, thus affecting the part accuracy and surface roughness. Secondly, the machine itself has location errors in axes X and Z during the processing, leading to the severest destruction in the steep section of the aspheric part by their resultant force. Lastly, anisotropy of diamond cutting tool hardness. The indentation hardness of the diamond is maximum in the direction of of face (100) and the front clearance has the best strength at tool point in the direction of . When cutting a steep aspheric part with large sagittal height, a bigger included angle of the diamond tool point arc will be used, and there will be a more deviation from the lattice direction. So the tool hardness is consistently decreased, resulting in a rapid wear of the cutting tool when turning the steep section of the aspheric part, thus the accuracy and roughness in machining an aspheric part become more difficult to control. The paper is concluded with the solutions of turning steep

  15. Computer Controlled Polishing of the Off-axis Aspheric Mirrors

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, the manufacturing and testing procedures to make large off-axis aspherical mirrors are presented. The difficulties in polishing and testing for both circular-aperture and rectangular-aperture mirrors are previewed, and a possible solution is given. The two mirrors have been polished by means of CCOS, and the final accuracy is 25nm rms for 770mm×210mm rectangular mirror and 20nm rms for φ600mm circular mirror. These results just meet the optical tolerances specified by the designer, and the manufacturing and testing procedures presented here show good ability to make the large off-axis aspherical mirrors.

  16. Enhanced optical power of GaN-based light-emitting diode with compound photonic crystals by multiple-exposure nanosphere-lens lithography

    Science.gov (United States)

    Zhang, Yonghui; Wei, Tongbo; Xiong, Zhuo; Shang, Liang; Tian, Yingdong; Zhao, Yun; Zhou, Pengyu; Wang, Junxi; Li, Jinmin

    2014-07-01

    The light-emitting diodes (LEDs) with single, twin, triple, and quadruple photonic crystals (PCs) on p-GaN are fabricated by multiple-exposure nanosphere-lens lithography (MENLL) process utilizing the focusing behavior of polystyrene spheres. Such a technique is easy and economical for use in fabricating compound nano-patterns. The optimized tilted angle is decided to be 26.6° through mathematic calculation to try to avoid the overlay of patterns. The results of scanning electron microscopy and simulations reveal that the pattern produced by MENLL is a combination of multiple ovals. Compared to planar-LED, the light output power of LEDs with single, twin, triple, and quadruple PCs is increased by 14.78%, 36.03%, 53.68%, and 44.85% under a drive current 350 mA, respectively. Furthermore, all PC-structures result in no degradation of the electrical properties. The stimulated results indicate that the highest light extraction efficiency of LED with the clover-shape triple PC is due to the largest scattering effect on propagation of light from GaN into air.

  17. Off-Axis Aspheric Surfacing Using Sub-Aperture Tools

    Science.gov (United States)

    Feng, Yunpeng; Qiao, Xiaoyan; Cheng, Haobo; Tam, Hon-Yuen

    2013-10-01

    The off-axis aspheric surface used in modern optical systems widely can obtain nearly perfect quality, realize both small packet-size and low-mass, and avoid the central obscuration. But it is difficult to fabricate because of asymmetry. There are some key technologies during the testing and fabrication of off-axis asphere. In this article, we proposed a method of the best fit sphere based on non-negative minimized removal criterion. And a measured data fitting algorithm was presented to estimate the geometry parameters of off-axis aspheric surface. Then an off-axis mirror was fabricated, and the interferometrically measured data was corrected to eliminate the distortion introduced by null compensator in every run. Finally, the surface error of off-axis mirror reduced to pv = 0.372λ, rms = 0.046λ, the surface roughness reached 0.72 nm. These methods mentioned in the article are suitable for off-axis aspheric optics.

  18. Grinding and polishing technology by computer controlled active lap for Φ1250mmF/1.5 aspheric mirror

    Science.gov (United States)

    Fan, Bin; Zeng, Zhige; Li, Xiaojin; Chen, Qiang; Gao, Pingqi; Zhou, Jiabin; Wan, Yongjian

    2010-05-01

    For large aspheric optical elements, Computer Controlled Active Lap(CCAL) manufacturing which developed in IOE (Institute of Optics and Electronics, Chinese Academy of Science), have some advantages such as higher manufacturing efficiency, lower middle-frequency and high-frequency errors comparing the fixed lapping technology and CCOS(Computer Controlled Optical Surface) technology. A paraboloid surface of Φ1250mmF/1.5 was grinded by the active lap bonded with ceramic pills, as well as polished will pitch bonded active lap. During polishing processing a null lens was designed to test the paraboloid surface, the final testing data of RMS with ZYGO interferometer reached to 0.027λ(λ=0.6328μm).

  19. Effects of Different Contact Lens Designs on Visual Quality Among the Soft Spherical Contact Lens Users

    Directory of Open Access Journals (Sweden)

    Mustafa Demir

    2013-10-01

    Full Text Available Purpose: To evaluate the effects of different lens designs on visual quality among soft spherical contact lens users. Material and Method: Forty eyes of twenty patients from our contact lens unit were included in this study. Refractive errors of the patients were between -0.50 and -6.0 diopters with 0.05. Total higher order aberration mean rms value was 0.29±0.10 µm without glasses, while it was 0.33±0.10 µm with Balafilcon A lenses and 0.31±0.10 µm with Senofilcon A lenses. Higher order aberration values measured after contact lens application did not show a significant difference for two contact lens designs (p>0.05. Discussion: High and low contrast sensitivity values were better with spectacles compared to contact lenses. We did not observe significant difference in higher order aberration values and visual quality between aspheric and spheric designed lenses. (Turk J Ophthalmol 2013; 43: 321-5

  20. A novel in-situ measuring technique for aspheric surface

    Science.gov (United States)

    Zhang, Chuan; Wang, Ping; Chen, Yaolong

    2011-11-01

    In this paper, a novel in-situ surface measuring technique for optical elements with aspheric surface is presented. It is a contact type probe, and can be used for measuring ground surfaces. The theory of this technique develops from coordinate measuring machine (CMM), and the measurement accuracy of this technique is depended on the accuracy of computer numerical controlled (CNC). By installing a special equipment with high accuracy measuring head in main spindle of CNC machine, and moving the probe along the path which is described by a mathematical aspheric expression precisely, we could get relative errors of sag height of any position in this path. With this technique, the repeat positioning error caused by traditional off-line measurement will be avoided. The author also has finished a special software with VC++ 6.0. With this software, the form error of ground work piece could be corrected rapidly. This software can calculate and handle the arrangement automatically with all parameters which are required to input in operation interface. In the correction stage, the software can analyze and process error data and generate a new NC program with corrected data for next grinding stage. After 2 or 3 times measuring and correction, the surface shape error of the aspheric optical element will be less than 1μm. The finished work piece has a very good surface finish and can be polished with high quality.

  1. Treating asphericity in fuel particle pressure vessel modeling

    Science.gov (United States)

    Miller, Gregory K.; Wadsworth, Derek C.

    1994-07-01

    The prototypical nuclear fuel of the New Production Modular High Temperature Gas-Cooled Reactor (NP-MHTGR) consists of spherical TRISO-coated particles suspended in graphite cylinders. The coating layers surrounding the fuel kernels in these particles consist of pyrolytic carbon layers and a silicon carbide layer. These coating layers act as a pressure vessel which retains fission product gases. In the operating conditions of the NP-MHTGR, a small percentage of these particles (pressure vessels) are expected to fail due to the pressure loading. The fuel particles of the NP-MHTGR deviate to some degree from a true spherical shape, which may have some effect on the failure percentages. A method is presented that treats the asphericity of the particles in predicting failure probabilities for particle samples. It utilizes a combination of finite element analysis and Monte Carlo sampling and is based on the Weibull statistical theory. The method is used here to assess the effects of asphericity in particles of two common geometric shapes, i.e. faceted particles and ellipsoidal particles. The method presented could be used to treat particle anomalies other than asphericity.

  2. Measurement of large aspheric surfaces by annular subaperture stitching interferometry

    Institute of Scientific and Technical Information of China (English)

    Xiaokun Wang; Lihui Wang; Longhai Yin; Binzhi Zhang; Di Fan; Xuejun Zhang

    2007-01-01

    A new method for testing aspheric surfaces by annular subaperture stitching interferometry is introduced.It can test large-aperture and large-relative-aperture aspheric surfaces at high resolution, low cost, and high efficiency without auxiliary null optics. The basic principle of the method is described, the synthetical optimization stitching model and effective algorithm are established based on simultaneous least-square fitting. A hyperboloid with an aperture of 350 mm is tested by this method. The obtained peak-to-valley (PV) and root-mean-square (RMS) values of the surface error after stitching are 0.433λ and 0.052λ (λis 632.8 nm), respectively. The reconstructed surface map is coincide with the entire surface map from null test, and the difference of PV and RMS errors between them are 0.031λ and 0.005λ, respectively.This stitching model provides another quantitive method for testing large aspheric surfaces besides null compensation.

  3. Lens Model

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory of probabil......Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory...... of probabilistic functionalism, and concerns the environment and the mind, and adaptation by the latter to the former. This entry is about the lens model, and probabilistic functionalism more broadly. Focus will mostly be on firms and their employees, but, to fully appreciate the scope, we have to keep in mind...

  4. Finite Element Analysis of the LOLA Receiver Telescope Lens

    Science.gov (United States)

    Matzinger, Elizabeth

    2007-01-01

    This paper presents the finite element stress and distortion analysis completed on the Receiver Telescope lens of the Lunar Orbiter Laser Altimeter (LOLA). LOLA is one of six instruments on the Lunar Reconnaissance Orbiter (LRO), scheduled to launch in 2008. LOLA's main objective is to produce a high-resolution global lunar topographic model to aid in safe landings and enhance surface mobility in future exploration missions. The Receiver Telescope captures the laser pulses transmitted through a diffractive optical element (DOE) and reflected off the lunar surface. The largest lens of the Receiver Telescope, Lens 1, is a 150 mm diameter aspheric lens originally designed to be made of BK7 glass. The finite element model of the Receiver Telescope Lens 1 is comprised of solid elements and constrained in a manner consistent with the behavior of the mounting configuration of the Receiver Telescope tube. Twenty-one temperature load cases were mapped to the nodes based on thermal analysis completed by LOLA's lead thermal analyst, and loads were applied to simulate the preload applied from the ring flexure. The thermal environment of the baseline design (uncoated BK7 lens with no baffle) produces large radial and axial gradients in the lens. These large gradients create internal stresses that may lead to part failure, as well as significant bending that degrades optical performance. The high stresses and large distortions shown in the analysis precipitated a design change from BK7 glass to sapphire.

  5. Design of a solar-blind ultraviolet zoom lens in corona detection

    Science.gov (United States)

    Kang, Sirui; Fan, Wenwen; Chen, Yu

    2016-11-01

    Based on the requirements of corona detection on searching targets with large field of view and detecting objects with small field of view, a refractive zoom optical system using mechanical compensation technology, which operates at 0.24μm~0.28μm wavelength ,is designed with aspherical surfaces. S8844-0909 ultraviolet CCD is selected as a sensor with pixel size 24μm×24μm. The zooming region is 35mm~70mm with F number of 3.5 and the corresponding field of view of 7°~14°.The zoom lens consists of seven lenses with two aspherical surfaces, so it has the advantages of compact size and simple structure. The results show that in full zooming range, the MTF values over all fields of view are above 0.8 at cut-off frequency 21lp/mm. The distortion is less than 5%.The zoom lens system has good image quality and stable image plane, which meets the overall design requirements of the optical system. Keywords: Corona detection, Zoom lens, Aspheric surface

  6. Application of the NANOMEFOS non-contact measurement machine in asphere and freeform optics production

    NARCIS (Netherlands)

    Henselmans, R.; Gubbels, G.P.H.; Drunen, C. van

    2010-01-01

    The NANOMEFOS machine is capable of fast, non-contact and universal measurement of aspheres and freeforms, up to ø500 mm with a measurement uncertainty below 30 nm (2σ). It is now being applied in asphere and freeform production at TNO.

  7. Clinical comparison of the optical performance of aspheric and spherical intraocular lenses

    NARCIS (Netherlands)

    van Gaalen, Kim W.; Koopmans, Steven A.; Jansonius, Nomdo M.; Kooijman, Aart C.

    2010-01-01

    PURPOSE: To compare the optical performance of aspheric Tecnis ZA9003 and spherical Sensar AR40e intraocular lenses (IOLs). SETTING: Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. METHODS: An aspheric IOL was implan

  8. CYLINDER LENS ALIGNMENT IN THE LTP

    Energy Technology Data Exchange (ETDEWEB)

    TAKACS, P.Z.

    2005-07-26

    The Long Trace Profiler (LTP), is well-suited for the measurement of the axial figure of cylindrical mirrors that usually have a long radius of curvature in the axial direction but have a short radius of curvature in the sagittal direction. The sagittal curvature causes the probe beam to diverge in the transverse direction without coming to a focus on the detector, resulting in a very weak signal. It is useful to place a cylinder lens into the optical system above the mirror under test to refocus the sagittal divergence and increase the signal level. A positive cylinder lens can be placed at two positions above the surface: the Cat's Eye reflection position and the Wavefront-Matching position. The Cat's Eye position, is very tolerant to mirror misalignment, which is not good if absolute axial radius of curvature is to be measured. Lateral positioning and rotational misalignments of lens and the mirror combine to produce unusual profile results. This paper looks at various alignment issues with measurements and by raytrace simulations to determine the best strategy to minimize radius of curvature errors in the measurement of cylindrical aspheres.

  9. High precision optical finishing of lightweight silicon carbide aspheric mirror

    Science.gov (United States)

    Kong, John; Young, Kevin

    2010-10-01

    Critical to the deployment of large surveillance optics into the space environment is the generation of high quality optics. Traditionally, aluminum, glass and beryllium have been used; however, silicon carbide becomes of increasing interest and availability due to its high strength. With the hardness of silicon carbide being similar to diamond, traditional polishing methods suffer from slow material removal rates, difficulty in achieving the desired figure and inherent risk of causing catastrophic damage to the lightweight structure. Rather than increasing structural capacity and mass of the substrate, our proprietary sub-aperture aspheric surface forming technology offers higher material removal rates (comparable to that of Zerodur or Fused Silica), a deterministic approach to achieving the desired figure while minimizing contact area and the resulting load on the optical structure. The technology performed on computer-controlled machines with motion control software providing precise and quick convergence of surface figure, as demonstrated by optically finishing lightweight silicon carbide aspheres. At the same time, it also offers the advantage of ideal pitch finish of low surface micro-roughness and low mid-spatial frequency error. This method provides a solution applicable to all common silicon carbide substrate materials, including substrates with CVD silicon carbide cladding, offered by major silicon carbide material suppliers. This paper discusses a demonstration mirror we polished using this novel technology. The mirror is a lightweight silicon carbide substrate with CVD silicon carbide cladding. It is a convex hyperbolic secondary mirror with 104mm diameter and approximately 20 microns aspheric departure from best-fit sphere. The mirror has been finished with surface irregularity of better than 1/50 wave RMS @632.8 nm and surface micro-roughness of under 2 angstroms RMS. The technology has the potential to be scaled up for manufacturing capabilities of

  10. Solving surface parameters of conic asphere mirror based on computer simulation

    Science.gov (United States)

    Huang, Chuan-ke; Wu, Yong-qian; Fan, Bin; Lei, Bai-ping

    2016-09-01

    Radius of curvature R and conic constant k are important parameters of aspheres.Null testing or CGH are usually used to evaluate the processing quality of aspheric mirrors in fabricating process . When the null compensator emerges a problem, additional method to ensure the accuracy of paraxial radius of curvature and conic constant is required. Based on the equation of conic aspheric, the computing model from which the paraxial radius of curvature R and conic constant k can be obtained was established, and a set of solving algorithm using singular value decomposition (SVD) method was derived. The simulating result of a 1800mm aspheric mirror is presented and the solving precision reaches R=6120+/-0.026mm, k=-1.0194+/-0.0008, thus the supplement to null testing of aspheric mirror is achieved effectively .

  11. Direct design of aspherical lenses for extended non-Lambertian sources in three-dimensional rotational geometry.

    Science.gov (United States)

    Wu, Rengmao; Hua, Hong

    2016-01-25

    Illumination design used to redistribute the spatial energy distribution of light source is a key technique in lighting applications. However, there is still no effective illumination design method for extended sources, especially for extended non-Lambertian sources. What we present here is to our knowledge the first direct method for extended non-Lambertian sources in three-dimensional (3D) rotational geometry. In this method, both meridional rays and skew rays of the extended source are taken into account to tailor the lens profile in the meridional plane. A set of edge rays and interior rays emitted from the extended source which will take a given direction after the refraction of the aspherical lens are found by the Snell's law, and the output intensity at this direction is then calculated to be the integral of the luminance function of the outgoing rays at this direction. This direct method is effective for both extended non-Lambertian sources and extended Lambertian sources in 3D rotational symmetry, and can directly find a solution to the prescribed design problem without cumbersome iterative illuminance compensation. Two examples are presented to demonstrate the effectiveness of the proposed method in terms of performance and capacity for tackling complex designs.

  12. Systematic uncertainties from halo asphericity in dark matter searches

    Energy Technology Data Exchange (ETDEWEB)

    Bernal, Nicolás [ICTP South American Institute for Fundamental Research, Instituto de Física Teórica, Universidade Estadual Paulista, São Paulo (Brazil); Forero-Romero, Jaime E. [Departamento de Física, Universidad de los Andes, Cra. 1 No. 18A-10, Edificio Ip, Bogotá (Colombia); Garani, Raghuveer [Bethe Center for Theoretical Physics and Physikalisches Institut, Universität Bonn, Nußallee 12, D-53115 Bonn,Germany (Germany); Palomares-Ruiz, Sergio, E-mail: nicolas@ift.unesp.br, E-mail: je.forero@uniandes.edu.co, E-mail: garani@th.physik.uni-bonn.de, E-mail: sergio.palomares.ruiz@ific.uv.es [Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València, Apartado de Correos 22085, E-46071, València (Spain)

    2014-09-01

    Although commonly assumed to be spherical, dark matter halos are predicted to be non-spherical by N-body simulations and their asphericity has a potential impact on the systematic uncertainties in dark matter searches. The evaluation of these uncertainties is the main aim of this work, where we study the impact of aspherical dark matter density distributions in Milky-Way-like halos on direct and indirect searches. Using data from the large N-body cosmological simulation Bolshoi, we perform a statistical analysis and quantify the systematic uncertainties on the determination of local dark matter density and the so-called J factors for dark matter annihilations and decays from the galactic center. We find that, due to our ignorance about the extent of the non-sphericity of the Milky Way dark matter halo, systematic uncertainties can be as large as 35%, within the 95% most probable region, for a spherically averaged value for the local density of 0.3-0.4 GeV/cm {sup 3}. Similarly, systematic uncertainties on the J factors evaluated around the galactic center can be as large as 10% and 15%, within the 95% most probable region, for dark matter annihilations and decays, respectively.

  13. From AGB Stars to Aspherical Planetary Nebulae - An Observational Perspective

    Science.gov (United States)

    Sahai, R.

    2014-04-01

    Most stars that leave the main sequence in a Hubble time will end their lives, evolving through the Asymptotic Giant Branch (AGB), Preplanetary Nebula (PPN) and Planetary Nebula (PN) evolutionary phases. The heavy mass loss which occurs during the AGB phase is important across astrophysics, dramatically changing the course of stellar evolution, dominantly contributing to the dust content of the interstellar medium, and influencing its chemical composition. Yet stellar evolution from the beginning of the AGB phase to the PN phase remains poorly understood, especially the dramatic transformation that occurs in the morphology of the mass-ejecta as AGB stars and their round circumstellar envelopes evolve into mostly PNe, the majority of which deviate strongly from spherical symmetry. In this review, I describe the observations, spanning the wavelength range from X-rays to millimeter wavelengths, that have contributed to our current understanding of the physical processes responsible for the formation of aspherical PNe. I conclude by a brief summary of future observations using current and upcoming facilities such as HST, Chandra, ALMA and JWST that can help in addressing the major unsolved problems in the study of aspherical PNe.

  14. Comparative evaluation of visual outcomes and corneal asphericity after laser-assisted in situ keratomileusis with the six-dimension Amaris excimer laser system

    Science.gov (United States)

    Piao, JunJie; Li, Ying-Jun; Whang, Woong-Joo; Choi, Mihyun; Kang, Min Ji; Lee, Jee Hye; Yoon, Geunyoung; Joo, Choun-Ki

    2017-01-01

    Purpose To compare the visual and refractive outcomes after laser-assisted in situ keratomileusis (LASIK) surgery for correction of myopia or myopic astigmatism using a six-dimensional Amaris excimer laser. Methods In this retrospective cohort study, we enrolled 47 eyes of 28 patients (age: 19–36 years) with myopia or myopic astigmatism. We used the Custom Ablation Manager protocol and performed ablations with the SCHWIND AMARIS system. LASIK flaps were cut with an iFS Advanced Femtosecond Laser. Mean static (SCC) and dynamic cyclotorsion (DCC) were evaluated. Visual and refractive outcomes were evaluated during 6 months’ follow-up. Corneal asphericity (Q-value) was analyzed at 4 months postoperatively. Results The spherical equivalent (SE) reduction was statistically significant reduce 1 day after refractive surgery (P Free mode (AF) and 90% in the Corneal Wavefront mode (CW). SCC measurements were within ± 5 degrees in 57% (AF) and 68% (CW) of eyes. Mean DCC was within ± 1 degree in 96% (AF) or 95% (CW) of cases. At 6 months, the uncorrected distance visual acuity was 20/25 or better in all eyes. At last follow-up, both steep and flat keratometry values had significantly flattened in both groups (P < 0.001). Corneal asphericity also increased significantly during the postoperative period for an 8-mm corneal diameter (P < 0.001). Conclusions LASIK for myopia or myopic compound astigmatism correction using the six-dimensional AMARIS 750S excimer laser is safe, effective, and predictable. Postoperative corneal asphericity can be analyzed by linear regression to predict the changes in postoperative corneal asphericity with this approach. PMID:28187180

  15. Milking the spherical cow: on aspherical dynamics in spherical coordinates

    CERN Document Server

    Pontzen, Andrew; Teyssier, Romain; Governato, Fabio; Gualandris, Alessia; Roth, Nina; Devriendt, Julien

    2015-01-01

    Galaxies and the dark matter halos that host them are not spherically symmetric, yet spherical symmetry is a helpful simplifying approximation for idealised calculations and analysis of observational data. The assumption leads to an exact conservation of angular momentum for every particle, making the dynamics unrealistic. But how much does that inaccuracy matter in practice for analyses of stellar distribution functions, collisionless relaxation, or dark matter core-creation? We provide a general answer to this question for a wide class of aspherical systems; specifically, we consider distribution functions that are "maximally stable", i.e. that do not evolve at first order when external potentials (which arise from baryons, large scale tidal fields or infalling substructure) are applied. We show that a spherically-symmetric analysis of such systems gives rise to the false conclusion that the density of particles in phase space is ergodic (a function of energy alone). Using this idea we are able to demonstra...

  16. Critical phenomena in the aspherical gravitational collapse of radiation fluids

    CERN Document Server

    Baumgarte, Thomas W

    2015-01-01

    We study critical phenomena in the gravitational collapse of a radiation fluid. We perform numerical simulations in both spherical symmetry and axisymmetry, and observe critical scaling in both supercritical evolutions, which lead to the formation of a black hole, and subcritical evolutions, in which case the fluid disperses to infinity and leaves behind flat space. We identify the critical solution in spherically symmetric collapse, find evidence for its universality, and study the approach to this critical solution in the absence of spherical symmetry. For the cases that we consider, aspherical deviations from the spherically symmetric critical solution decay in damped oscillations in a manner that is consistent with the behavior found by Mart\\'in-Garc\\'ia and Gundlach in perturbative calculations. Our simulations are performed with an unconstrained evolution code, implemented in spherical polar coordinates, and adopting "moving-puncture" coordinates.

  17. Integration of Full-Spectrum Metrology and Polishing for Rapid Production of Large Aspheres Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design, build, and test a major new instrument capable of both measuring and polishing the surface of aspheric mirrors up to 1.2 meters in diameter,...

  18. Very large computer generated holograms for precision metrology of aspheric optical surfaces Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Both ground and space telescopes employ aspheric mirrors. A particular example is the X-ray telescope where primary and secondary mirrors have nearly cylindrical...

  19. Contact lens in keratoconus

    Directory of Open Access Journals (Sweden)

    Varsha M Rathi

    2013-01-01

    Full Text Available Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP lenses, soft and soft toric lenses, piggy back contact lenses (PBCL, hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL.

  20. 新型多焦点人工晶状体临床应用的研究进展%Clinical application of new types of multifocal intraocular lens

    Institute of Scientific and Technical Information of China (English)

    张景尚; 万修华

    2015-01-01

    近年来新型多焦点人工晶状体(IOL)如非球面多焦点IOL、Toric多焦点IOL和非球面Toric多焦点IOL等的不断问世及临床应用,更好地改善了白内障患者术后的生活视力、工作视力以及生存质量.对于新型多焦点IOL的适应证应严格掌握,以使患者术后获得最佳效果.%In recent years new types of multifocal intraocular lens have been developed,such as aspheric multifocal intraocular lens,Toric multifocal intraocular lens and aspheric Toric multifocal intraocular lens and so on.The vision in life and work and the quality of life in patients with cataract were significantly improved after phacoemulsification with the new types of multifocal intraocular lens.At the same time there should be a strict indications for the new types of multifocal intraocular lens,so as to make the cataract patients implanted multifocal intraocular lens getting the best visual quality.

  1. Noncontact optical measurement of lens capsule thickness ex vivo

    Science.gov (United States)

    Ziebarth, Noel M.; Manns, Fabrice; Uhlhorn, Stephen; Parel, Jean-Marie

    2004-07-01

    Purpose: To design a non-contact optical system to measure lens capsule thickness in cadaver eyes. Methods: The optical system uses a 670nm laser beam delivered to a single-mode fiber coupler. The output of the fiber coupler is focused onto the tissue using an aspheric lens (NA=0.68) mounted on a motorized translation stage. Light reflected from the sample is collected by the fiber coupler and sent to a silicon photodiode connected to a power meter. Peaks in the power signal are detected when the focal point of the aspheric lens coincides with the capsule boundaries. The capsule thickness is proportional to the distance between successive peaks. Anterior and posterior lens capsule thickness measurements were performed on 13 human, 10 monkey, and 34 New Zealand white rabbit lenses. The cadaver eyes were prepared for optical measurements by bonding a PMMA ring on the sclera. The posterior pole was sectioned, excess vitreous was removed, and the eye was placed on a Teflon slide. The cornea and iris were then sectioned. After the experiments, the lenses were excised, placed in 10% buffered formalin, and prepared for histology. Results: Central anterior lens capsule thickness was 9.4+/-2.9μm (human), 11.2+/-6.6μm (monkey), and 10.3+/-3.6μm (rabbit) optically and 14.9+/-1.6μm (human), 17.7+/-4.9μm (monkey), and 12.6+/-2.3μm (rabbit) histologically. The values for the central posterior capsule were 9.4+/-2.9μm (human), 6.6+/-2.5μm (monkey), and 7.9+/-2.3μm (rabbit) optically and 4.6+/-1.4μm (human), 4.5+/-1.2μm (monkey), and 5.7+/-1.7μm (rabbit) histologically. Conclusions: This study demonstrates that a non-contact optical system can successfully measure lens capsule thickness in cadaver eyes.

  2. Intraocular Lens Multifocality Combined with the Compensation for Corneal Spherical Aberration:A New Concept ofPresbyopia-CorrectingIntraocular Lens

    Directory of Open Access Journals (Sweden)

    Reiner Friedrich

    2012-10-01

    Full Text Available The outcomes of a prospective consecutive study aimed at evaluating the visual and refractive benefit after cataract surgery with the implantation of the aspheric diffractive multifocal intraocular lens (IOL Tecnis ZMB00 (Abbott Medical Optics are reported. A total of 31 eyes of 19 patients (age range, 40 to 81 years underwent phacoemulsification surgery with implantation of this aspheric multifocal IOL. At 6 months after surgery, postoperative spherical equivalent was within ±1.00 D in 96.8% of eyes, with 94.7% of patients presenting a postoperative binocular far LogMAR uncorrected visual acuity (UCVA of 0.1 or better. Far best-corrected distance VA improved significantly (p < 0.01, with postoperative values of 0.1 or better in 96.8% of eyes. Postoperative near UCVA was 0.10 (equivalent to J1 or better in 93.55% of eyes. Furthermore, the IOL power was found to be very poorly correlated with the postoperative far LogMAR (r = 0.13 and near UCVA (r = 0.13. In conclusion, the aspheric diffractive multifocal IOL Tecnis ZMB00 provides a restoration of the far and near visual function after phacoemulsification surgery for cataract removal or presbyopia correction, which is predictable and independent from the optical power of the implanted IOL.

  3. Rapid cooled lens cell

    Science.gov (United States)

    Stubbs, David M.; Hsu, Ike C.

    1991-12-01

    This paper describes the optomechanical design, thermal analysis, fabrication, and test evaluation processes followed in developing a rapid cooled, infrared lens cell. Thermal analysis was the key engineering discipline exercised in the design phase. The effect of thermal stress on the lens, induced by rapid cooling of the lens cell, was investigated. Features of this lens cell that minimized the thermal stress will be discussed in a dedicated section. The results of thermal analysis on the selected lens cell design and the selection of the flow channel design in the heat exchanger will be discussed. Throughout the paper engineering drawings, illustrations, analytical results, and photographs of actual hardware are presented.

  4. Multi-Dimensional Simulations of Radiative Transfer in Aspherical Core-Collapse Supernovae

    CERN Document Server

    Tanaka, Masaomi; Mazzali, Paolo A; Nomoto, Ken'ichi

    2008-01-01

    We study optical radiation of aspherical supernovae (SNe) and present an approach to verify the asphericity of SNe with optical observations of extragalactic SNe. For this purpose, we have developed a multi-dimensional Monte-Carlo radiative transfer code, SAMURAI (SupernovA MUlti-dimensional RAdIative transfer code). The code can compute the optical light curve and spectra both at early phases (<~ 40 days after the explosion) and late phases (~ 1 year after the explosion), based on hydrodynamic and nucleosynthetic models. We show that all the optical observations of SN 1998bw (associated with GRB 980425) are consistent with polar-viewed radiation of the aspherical explosion model with kinetic energy 20 x 10^{51} ergs. Properties of off-axis hypernovae are also discussed briefly.

  5. Aspherical surfaces design for extreme ultraviolet lithographic objective with correction of thermal aberration

    Science.gov (United States)

    Liu, Yan; Li, Yanqiu

    2016-09-01

    At present, few projection objectives for extreme ultraviolet (EUV) lithography pay attention to correct thermal aberration in optical design phase, which would lead to poor image quality in a practical working environment. We present an aspherical modification method for helping the EUV lithographic objective additionally correct the thermal aberration. Based on the thermal aberration and deformation predicted by integrated optomechanical analysis, the aspherical surfaces in an objective are modified by an iterative algorithm. The modified aspherical surfaces could correct the thermal aberration and maintain the initial high image quality in a practical working environment. A six-mirror EUV lithographic objective with 0.33-numerical aperture is taken as an example to illustrate the presented method. The results show that the thermal aberration can be corrected effectively, and the image quality of the thermally deformed system is improved to the initial design level, which proves the availability of the method.

  6. Optimization on manufacturing and testing technology for rectangle aperture off-axis aspheric mirror fine grinding

    Science.gov (United States)

    Chen, Xi; Guo, Peiji; Wang, Dongdong

    2016-10-01

    High precision aspheric surface can be obtained conveniently by using single point diamond turning technology, liquidmagnetic polishing technology and ion beam polishing technology, but the costs of manufacturing is too enormous to be widely used. In fact, in the field of optical processing, the most commonly used technical solution is still making a best fit sphere firstly compared with aspheric equation, and then remove the material on the glass to correct the error between aspheric and best fit sphere by precision grinding and precision polishing. The resolving of the best-fit sphere and the material removal, however, is a very important problem during the fabrications. The two dimensional maps of surface error between the best fit sphere and the corresponding aspheric surface shows W shaped which has the maximum removal at the center and the edge of the workpeace and gradually reduces to zero at the 70.7 percent of the diameter. In the process of deterministic optical manufacturing, the edge effect will arise because of the change of machining conditions when polishing tool locates in edge area, which will lower the surface accuracy of workpiece and debase machining efficiency. W shaped error distribution and the edge effect will make it difficult to remove the error on the edge of the workpiece. Aiming at the situation, an algorithm available for control of edge effect is proposed. Considering the requirement of minimum material removal and the control of edge effect, the radius of the anti-edge effect sphere is calculated by programming. The advantage of the algorithm is shown by the comparison of results derived from new algorithm and empirical equation. At the same time, the application in the off-axis asphere fabrications also proves the correctness of the algorithm. This algorithm is very helpful for the theory and practice of the fabrications of off-axis asphere.

  7. Visual and Refractive Outcomes after Cataract Surgery with Implantation of a New Toric Intraocular Lens

    Directory of Open Access Journals (Sweden)

    Cinzia Mazzini

    2013-06-01

    Full Text Available Purpose: The aim of this study was to evaluate and report the visual, refractive and aberrometric outcomes of cataract surgery with implantation of the new aspheric Tecnis ZCT toric intraocular lens (IOL in eyes with low to moderate corneal astigmatism. Methods: We conducted a prospective study of 19 consecutive eyes of 17 patients (mean age: 78 years with a visually significant cataract and moderate corneal astigmatism [higher than 1 diopter (D] undergoing cataract surgery with implantation of the aspheric Tecnis ZCT toric IOL (Abbott Medical Optics. Visual, refractive and aberrometric changes were evaluated during a 6-month follow-up. Ocular aberrations as well as IOL rotation were evaluated by means of the OPD-Station II (Nidek. Results: The six-month postoperative spherical equivalent and power vector components of the refractive cylinder were within ±0.50 D in all eyes (100%. Postoperative logMAR uncorrected and corrected distance visual acuities (UDVA/CDVA were 0.1 (about 20/25 or better in almost all eyes (94.74%. The mean logMAR CDVA improved significantly from 0.41 ± 0.23 to 0.02 ± 0.05 (p Conclusion: Cataract surgery with implantation of the aspheric Tecnis ZCT IOL is a predictable and effective procedure for visual rehabilitation in eyes with cataract and low to moderate corneal astigmatism, providing an excellent postoperative ocular optical quality.

  8. High-efficiency fabrication of aspheric microlens arrays by holographic femtosecond laser-induced photopolymerization

    Science.gov (United States)

    Hu, Yanlei; Chen, Yuhang; Ma, Jianqiang; Li, Jiawen; Huang, Wenhao; Chu, Jiaru

    2013-09-01

    Manufacture of aspheric microlens has always been technically challenging for conventional approaches due to their complex curved profile and tiny sizes. Two-photon polymerization is capable of producing arbitrary shape with high spatial resolution, apart from the disadvantage of ultra-low rate of yield resulting from point-by-point writing strategy. Here, we report parallel fabrication of aspheric microlens arrays (AMLAs) by taking advantage of holographic femtosecond laser direct-writing. The inherent constraints of the spatial light modulator are taken into consideration for achieving improved intensity uniformity and enhanced diffraction efficiency. Closely-packed AMLAs with designable optical parameters are readily fabricated with excellent optical performance.

  9. Contact lens in keratoconus

    OpenAIRE

    Varsha M Rathi; Preeji S Mandathara; Srikanth Dumpati

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the En...

  10. Iatrogenic Lens Injuries

    Directory of Open Access Journals (Sweden)

    Ümit Kamış

    2012-12-01

    Full Text Available During intraocular surgery, undesired damages of various etiology may occur in adjacent tissues. One of these tissues is the crystalline lens, which may be traumatized both in anterior segment and posterior segment surgeries, and when damaged, it usually causes marked decrease in visual acuity. The leading causes of iatrogenic lens injuries are intravitreal injection, laser iridotomy, phakic intraocular lens implantation, anterior chamber paracentesis, and vitreoretinal surgery. When crystalline lens damage occurs, its negative effect on visual function may be eliminated by performing cataract surgery intraoperatively or in elective conditions. (Turk J Ophthalmol 2012; 42: Supplement 27-30

  11. Variable aberration generator using a high-order even aspheric singlet for testing optical surfaces

    Science.gov (United States)

    Lu, Jinfeng; Chen, Shanyong; Xue, Shuai

    2016-10-01

    Traditional null optics is generally designed for a particular optical surface. It must be redesigned when the test surface is changed no matter the null optic is reflective, transmitted or a CGH. Development of advanced optical machining and testing based on deterministic figuring and null test makes it possible to apply high-order aspheres. This paper presents a plano-concave singlet to realize variable aberration correction for testing different surfaces. The concave surface is an even asphere with high-order terms. By changing the axial distances among the transmission sphere, the null singlet and the test surface, variable aberrations are generated to meet the aberration balance requirement for various surfaces. The residual aberrations are confirmed within the vertical dynamic range of measurement of the interferometer. It enables flexible testing of optical surfaces without dedicated null optics. The optical design verifies that the aspheric singlet can be used to test conic surfaces with different conic constant and radius of curvature ranging from ellipsoid, paraboloid to hyperboloid and an even asphere.

  12. Error analysis of a rotating mode diamond turning large aspherical mirrors

    Science.gov (United States)

    Han, Cheng-Shun; Zhang, Long-Jiang; Dong, Shen; Tan, Jiu-Bin

    2009-05-01

    A precision rotating mode diamond turnimg method used for machining large optical asphercial elements is introduced. The position errors between spindles of workpiece and cutting tool system are discussed, and error models of correctly forming the aspherical reference sphere are set up. The constructed models are used in adjusting the machine for ensuring the machining accuracy and efficiency.

  13. Problems on design of computer-generated holograms for testing aspheric surfaces: principle and calculation

    Institute of Scientific and Technical Information of China (English)

    Zhishan Gao; Meimei Kong; Rihong Zhu; Lei Chen

    2007-01-01

    Interferometric optical testing using computer-generated hologram (CGH) has provided an approach to highly accurate measurement of aspheric surfaces. While designing the CGH null correctors, we should make them with as small aperture and low spatial frequency as possible, and with no zero slope of phase except at center, for the sake of insuring lowisk of substrate figure error and feasibility of fabrication. On the basis of classic optics, a set of equations for calculating the phase function of CGH are obtained. These equations lead us to find the dependence of the aperture and spatial frequency on the axial diszance from the tested aspheric surface for the CGH. We also simulatethe ptical path difference error of the CGH relative to the accuracy of controlling laser spot during fabrication. Meanwhile, we discuss the constraints used to avoid zero slope of phase except at center and give a design result of the CGH for the tested aspheric surface. The results ensure the feasibility of designing a useful CGH to test aspheric urface fundamentally.

  14. Comparison of Optical Performance in Eyes Implanted With Aspheric Foldable, Spherical Foldable, and Rigid PMMA IOLs

    NARCIS (Netherlands)

    van Gaalen, Kim W.; Jansonius, Nomdo M.; Koopmans, Steven A.; Kooijman, Aart C.

    2011-01-01

    PURPOSE: To compare the optical performance of rigid spherical polymethylmethacrylate (PMMA), foldable spherical, and foldable aspheric intraocular lenses (IOLs). METHODS: Measurements were obtained monocularly from pseudophakic patients with a PMMA IOL (Ophtec PC265y or Rayner 105U), spherical Acry

  15. Practical retrace error correction in non-null aspheric testing: A comparison

    Science.gov (United States)

    Shi, Tu; Liu, Dong; Zhou, Yuhao; Yan, Tianliang; Yang, Yongying; Zhang, Lei; Bai, Jian; Shen, Yibing; Miao, Liang; Huang, Wei

    2017-01-01

    In non-null aspheric testing, retrace error forms the primary error source, making it hard to recognize the desired figure error from the aliasing interferograms. Careful retrace error correction is a must bearing on the testing results. Performance of three commonly employed methods in practical, i.e. the GDI (geometrical deviation based on interferometry) method, the TRW (theoretical reference wavefront) method and the ROR (reverse optimization reconstruction) method, are compared with numerical simulations and experiments. Dynamic range of these methods are sought out and the application is recommended. It is proposed that with aspherical reference wavefront, dynamic range can be further enlarged. Results show that the dynamic range of the GDI method is small while that of the TRW method can be enlarged with aspherical reference wavefront, and the ROR method achieves the largest dynamic range with highest accuracy. It is recommended that the GDI and TRW methods be applied to apertures with small figure error and small asphericity, and the ROR method for commercial and research applications calling for high accuracy and large dynamic range.

  16. Wafer-level fabrication of arrays of glass lens doublets

    Science.gov (United States)

    Passilly, Nicolas; Perrin, Stéphane; Albero, Jorge; Krauter, Johann; Gaiffe, Olivier; Gauthier-Manuel, Ludovic; Froehly, Luc; Lullin, Justine; Bargiel, Sylwester; Osten, Wolfgang; Gorecki, Christophe

    2016-04-01

    Systems for imaging require to employ high quality optical components in order to dispose of optical aberrations and thus reach sufficient resolution. However, well-known methods to get rid of optical aberrations, such as aspherical profiles or diffractive corrections are not easy to apply to micro-optics. In particular, some of these methods rely on polymers which cannot be associated when such lenses are to be used in integrated devices requiring high temperature process for their further assembly and separation. Among the different approaches, the most common is the lens splitting that consists in dividing the focusing power between two or more optical components. In here, we propose to take advantage of a wafer-level technique, devoted to the generation of glass lenses, which involves thermal reflow in silicon cavities to generate lens doublets. After the convex lens sides are generated, grinding and polishing of both stack sides allow, on the first hand, to form the planar lens backside and, on the other hand, to open the silicon cavity. Nevertheless, silicon frames are then kept and thinned down to form well-controlled and auto-aligned spacers between the lenses. Subsequent accurate vertical assembly of the glass lens arrays is performed by anodic bonding. The latter ensures a high level of alignment both laterally and axially since no additional material is required. Thanks to polishing, the generated lens doublets are then as thin as several hundreds of microns and compatible with micro-opto-electro-systems (MOEMS) technologies since they are only made of glass and silicon. The generated optical module is then robust and provide improved optical performances. Indeed, theoretically, two stacked lenses with similar features and spherical profiles can be almost diffraction limited whereas a single lens characterized by the same numerical aperture than the doublet presents five times higher wavefront error. To demonstrate such assumption, we fabricated glass

  17. Superlensing Microscope Objective Lens

    CERN Document Server

    Yan, Bing; Parker, Alan; Lai, Yukun; Thomas, John; Yue, Liyang; Monks, James

    2016-01-01

    Conventional microscope objective lenses are diffraction limited, which means that they cannot resolve features smaller than half the illumination wavelength. Under white light illumination, such resolution limit is about 250-300 nm for an ordinary microscope. In this paper, we demonstrate a new superlensing objective lens which has a resolution of about 100 nm, offering at least two times resolution improvement over conventional objectives in resolution. This is achieved by integrating a conventional microscope objective lens with a superlensing microsphere lens using a 3D printed lens adaptor. The new objective lens was used for label-free super-resolution imaging of 100 nm-sized engineering and biological samples, including a Blu-ray disc sample, semiconductor chip and adenoviruses. Our work creates a solid base for developing a commercially-viable superlens prototype, which has potential to transform the field of optical microscopy and imaging.

  18. Development of fabricating method for optical aspheric surface and fabricating method for high accuracy quadric surface mirror for solar furnace; Kogaku hikyumen no seisakuho no kaihatsu kara taiyoroyo koseido niji kyokumenkyo no sakuseiho made

    Energy Technology Data Exchange (ETDEWEB)

    Shishido, K. [Tohoku Gakuin Univ., Miyagi (Japan). Faculty of Engineering

    1996-03-29

    45 years have passed since the initiation of study on the fabricating method for optical aspheric surface. As examples of making prototypes for the `cam system,` fabrications of ellipsoidal surface mirror, parabolic mirror, segment type parabolic mirror, and particularly special asymmetric aspheric surface lens are quoted as successful cases. As regards the `link` system, a parabolic surface finishing machine for making matrices for soft formation of parabolic mirror segment glass was made on trial basis. Recently, a prototype of finishing machine for making a quadric surface finishing machine with higher accuracy was produced, which enabled preparation of more accurate matrices than in the past in the field of parabolic surface finishing machine, and actual ellipsoidal surface was machined by an ellipsoidal surface finishing machine. As regards solar furnace, study had been made to develop a method of producing a segment type glass mirror comprising a main mirror and a sub-mirror by a comparatively simple method and at high accuracy, and a promising result was obtained. 35 figs.

  19. Comparison between OPD-scan results and contrast sensitivity of three intraocular lenses: spheric AcrySof SN60AT, aspheric AcrySof SN60WF and multifocal AcrySof Restor lens Estudo comparativo da análise de frente de onda e sensibilidade ao contraste entre as lentes intra-oculares multifocal AcrySof Restor SN60D3, monofocal AcrySof SN60WF asférica e a monofocal SN60AT esférica

    Directory of Open Access Journals (Sweden)

    Celso Takashi Nakano

    2009-08-01

    Full Text Available Purpose: Compare the OPD-scan results and the contrast sensitivity in patients who had implantation of the AcrySof SN60D3 multifocal IOL, the AcrySof SA60AT spheric monofocal IOL and the AcrySof SN60AT aspheric monofocal IOL. Methods: Thirty-two eyes received the multifocal IOL, 32 eyes received the spheric monofocal IOL and 32 eyes received the aspheric monofocal IOL. They were closely paired in age, sex, pre-operative wavefront analysis and contrast sensitivity. All patients was tested with the OPD-scan aberrometer, ETDRS chart at 100% and 9% contrasts and contrast sensitivity. Results: Statistically significant differences were detected more total aberration in SN60AT group (KW = 9.42; p=0.009 when compared to SN60D3 group (p=0.016 and SN60WF group (p=0.0047. The SN60AT group (KW = 16.20; p=0.0003 showed with high spherical aberration values compared to the SN60WF (p=0.00046 and SN60D3 (p=0.0014 group. No significant differences were found between groups in far-distance VA measured using ETDRS at 100% and 9% contrast. The SN60D3 group compared to SN60AT group (p=0.016 had low contrast sensitivity (log units with statistical difference in 6.0 cpd (KW = 7.84; p=0.0199, but no statistical difference between SN60WF and SN60AT group (p=0.91 and SN60WF and SN60D3 group (p=0.051. The SN60D3 group had low contrast sensitivity performed under mesopic conditions (KW = 10.79; p=0,0045 in 6cpd spatial frequency compared to the SN60AT group (p=0.011 and to the SN60WF group (p=0.007 with statistical significant differences. Conclusion: In all analyzed parameters of OPD-scan aberrometry the aspheric and the multifocal IOLs provided less total and spherical aberrations than spheric IOLs. All IOLs provided an excellent high and low contrasts vision, the multifocal IOL was as good as the spheric and aspheric monofocal IOLs.Objetivo: Comparar a sensibilidade ao contraste e análise de "wavefront" com OPD-scan em pacientes submetidos a cirurgia de facoemulsifica

  20. Transferability of glass lens molding

    Science.gov (United States)

    Katsuki, Masahide

    2006-02-01

    Sphere lenses have been used for long time. But it is well known that sphere lenses theoretically have spherical aberration, coma and so on. And, aspheric lenses attract attention recently. Plastic lenses are molded easily with injection machines, and are relatively low cost. They are suitable for mass production. On the other hand, glass lenses have several excellent features such as high refractive index, heat resistance and so on. Many aspheric glass lenses came to be used for the latest digital camera and mobile phone camera module. It is very difficult to produce aspheric glass lenses by conventional process of curve generating and polishing. For the solution of this problem, Glass Molding Machine was developed and is spreading through the market. High precision mold is necessary to mold glass lenses with Glass Molding Machine. The mold core is ground or turned by high precision NC aspheric generator. To obtain higher transferability of the mold core, the function of the molding machine and the conditions of molding are very important. But because of high molding temperature, there are factors of thermal expansion and contraction of the mold and glass material. And it is hard to avoid the factors. In this session, I introduce following items. [1] Technology of glass molding and the machine is introduced. [2] The transferability of glass molding is analyzed with some data of glass lenses molded. [3] Compensation of molding shape error is discussed with examples.

  1. Refractive outcomes of an advanced aspherically optimized profile for myopia corrections by LASIK: a retrospective comparison with the standard aspherically optimized profile

    Directory of Open Access Journals (Sweden)

    Meyer B

    2015-02-01

    Full Text Available Bertram Meyer,1 Georg Sluyterman van Langeweyde,2 Matthias Wottke2 1Augencentrum Köln, Cologne, Germany; 2Carl Zeiss Meditec AG, Jena, Germany Purpose: A retrospective comparison of refractive outcomes of a new, aspherically optimized profile with an enhanced energy correction feature (Triple-A and the conventionally used aspherically optimized profile (ASA, or aberration smart ablation for correction of low-to-high myopia.Setting: Augen-OP-Centrum, Cologne, GermanyDesign: Retrospective nonrandomized comparative studyMethods: A central database at the Augen-OP-Centrum was used to gather retrospective data for low-to-high myopia (up to -10 D. One hundred and seven eyes (56 patients were treated with the ASA profile, and 79 eyes (46 patients were treated with the Triple-A profile. Postoperative outcomes were evaluated at 1 month, 3 months, 6 months, and 1 year follow-up time points.Results: The Triple-A profile showed better predictability indicated by a significantly lower standard deviation of residuals (0.32–0.34 vs 0.36–0.44, Triple-A vs ASA in the 6-month to 1-year period. The Triple-A group had better stability across all time intervals and achieved better postoperative astigmatism improvements with significantly lower scatter. This group achieved better safety at 1 year, with 100% of eyes showing no change or gain in Snellen lines, compared with 97% in the ASA group. A better safety index was observed for the Triple-A group at later time points. The Triple-A group had a better efficacy index and a higher percentage of eyes with an uncorrected Snellen visual acuity of 20/20 or greater at all investigated follow-up time points.Conclusion: The new aspherically optimized Triple-A profile can safely and effectively correct low-to-high myopia. It has demonstrated superiority over the ASA profile in most refractive outcomes. Keywords: Triple-A, wavefront measurements, corneal aberrations, corneal asphericity, ablation profile

  2. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, M.A.; Foreman, L.R.

    1997-07-08

    This invention describes a method for fabricating an intraocular lens made from clear Teflon{trademark}, Mylar{trademark}, or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube. 13 figs.

  3. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, Mike A. (Albuquerque, NM); Foreman, Larry R. (Los Alamos, NM)

    1997-01-01

    This invention describes a method for fabricating an intraocular lens made rom clear Teflon.TM., Mylar.TM., or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube.

  4. Unitary lens semiconductor device

    Science.gov (United States)

    Lear, Kevin L.

    1997-01-01

    A unitary lens semiconductor device and method. The unitary lens semiconductor device is provided with at least one semiconductor layer having a composition varying in the growth direction for unitarily forming one or more lenses in the semiconductor layer. Unitary lens semiconductor devices may be formed as light-processing devices such as microlenses, and as light-active devices such as light-emitting diodes, photodetectors, resonant-cavity light-emitting diodes, vertical-cavity surface-emitting lasers, and resonant cavity photodetectors.

  5. Development of an aspheric 22-diopter 50-mm diameter magnifier Desenvolvimento de uma lupa asférica de 22 dioptrias de 50 mm de diâmetro

    Directory of Open Access Journals (Sweden)

    José Américo Bonatti

    2008-04-01

    Full Text Available PURPOSE: To develop in an interdisciplinary approach between ophthalmology and design areas an ergonomic +22-diopter 50-mm aspheric hand magnifier for low vision. METHODS: An aluminum cylinder was cut, processed using a lathe and carved to produce a ring that accommodated a 50-mm aspheric lens, with an external depression not to slide from the holder's fingers. A cylindrical steel bar was cut, processed using a lathe and carved in order to form an externally turned ring to be screwed into the internal thread of the aluminum ring, to maintain the lens in a steady position. Both rings were submitted to electrostatic painting with a dull black electrostatic Epoxi ink, except the lower border of the external ring, to indicate the correct side of the magnifier to face the material to be read. RESULTS: A 22-diopter 50-mm diameter aspheric lens magnifier with a black ring to be hold at its external circular depression was obtained in order to safely search the adequate reading focus with an inferior aluminum colored ring to face the object to be read and allow a less distorted reading. This is the first Brazilian high-magnification great-diameter magnifier for low vision that permits basically the focusing on an entire word, not only syllables, in order to allow a faster and more comfortable reading. CONCLUSIONS: By an interdisciplinary approach a 22-diopter 50-mm aspheric lens magnifier was developed with image and ergonomic characteristics such as to permit comfortable and adequate reading performance in cases of low vision.OBJETIVO: Desenvolver de modo interdisciplinar entre as áreas de oftalmologia e design uma lupa de mão ergonômica de +22 dioptrias de 50 mm de diâmetro asférica para baixa visão. MÉTODOS: Um cilindro de alumínio foi cortado, torneado e teve feita internamente uma rosca a fim de produzir um anel para acomodar uma lente asférica de 50 mm de diâmetro com uma depressão externa para não escorregar dos dedos do portador. Uma

  6. SOFTWARE-CONTROLLED SYSTEM OF ULTRA-PRECISION MACHINING AXISYMMETRIC ASPHERIC MIRROR

    Institute of Scientific and Technical Information of China (English)

    GUO Yinbiao; WEI Lizhen

    2006-01-01

    In order to improve machining accuracy and efficiency, a software-controlled system of ultra-precision machining for axisymmetric aspheric mirror, using techniques of error compensation,remote transmission and modularization, is designed based on industrial PC, Windows 2000 work platform and Visual Basic 6.0. By experiments, this system realizes functions of ultra-precision machining, machining error compensation, remote data transmission and automatic data transformation among first machining, compensation machining and accuracy measurement. The actual application shows that error compensation improves machining accuracy, remote transmission improves machining efficiency while modularization avoids repeated work and improves design efficiency. Therefore, the system has met ultra-precision machining need for aspheric mirror.

  7. Use of Virtual Medium in Designing of the CGH Wave Front Generator for Aspheric Testing

    Institute of Scientific and Technical Information of China (English)

    KANG Guo-guo; XIE Jing-hui; LIU Yi

    2007-01-01

    Design method and procedures of computer-generated hologram (CGH) used for aspheric test are introduced in detail.For CGH phase calculation,virtual medium which has zero refractive index at given wavelength is used to model ideal aspheric wavefront.Reflective Fresnel zones located in a ring area concentric to the CGH structure is designed to reduce or eliminate alignment errors.Substrate figure error,pattern distortion,etching and duty cycle variations that influence the reconstructed wavefront are quantitatively analyzed in theory and corresponding error equations are obtained to guide the tolerance distribution during CGH fabricating.A design example is given and the uncertainty of measurement achieves λ/20.

  8. Effection of grinding system rigidity ultra-precision grinding of aspheric mould and error compensation

    Science.gov (United States)

    Yin, S. H.; Gong, S.

    2016-10-01

    In ultra-precision oblique axis grinding process for machining micro aspherical mould, form error of aspherical surface is caused by the inconsistence elastic deformation of grinding system, which derived from differences velocity from inside to out. In this case, whole PV value can meet requirements, however, pits are produced in central after error compensation, which is unworkable. In this paper, mechanism of machining error caused by grinding system rigidity is analyzed, and experiments are carried out. Form error compensation grinding are carried out in the central local area, based on traditional error compensation method, which can effectively eliminate the pits of surface center. In this method, cemented carbide YG8 which diameter is about 6mm is ground. The results showed that the form accuracy under PV 200 nm and under PV 50 nm within the scope of 1 mm, and the surface roughness under Ra2nm.

  9. Non-Radial Instabilities and Progenitor Asphericities in Core-Collapse Supernovae

    CERN Document Server

    Mueller, B

    2014-01-01

    Since core-collapse supernova simulations still struggle to produce robust neutrino-driven explosions in 3D, it has been proposed that asphericities caused by convection in the progenitor might facilitate shock revival by boosting the activity of non-radial hydrodynamic instabilities in the post-shock region. We investigate this scenario in depth using 42 relativistic 2D simulations with multi-group neutrino transport to examine the effects of velocity and density perturbations in the progenitor for different perturbation geometries that obey fundamental physical constraints (like the anelastic condition). As a framework for analysing our results, we introduce semi-empirical scaling laws relating neutrino heating, average turbulent velocities in the gain region, and the shock deformation in the saturation limit of non-radial instabilities. The squared turbulent Mach number, , reflects the violence of aspherical motions in the gain layer, and explosive runaway occurs for ~0.3, corresponding to a reduction of t...

  10. Conformal interpolating algorithm based on B-spline for aspheric ultra-precision machining

    Science.gov (United States)

    Li, Chenggui; Sun, Dan; Wang, Min

    2006-02-01

    Numeric control machining and on-line compensation for aspheric surface are key techniques for ultra-precision machining. In this paper, conformal cubic B-spline interpolating curve is first applied to fit the character curve of aspheric surface. Its algorithm and process are also proposed and imitated by Matlab7.0 software. To evaluate the performance of the conformal B-spline interpolation, comparison was made between linear and circular interpolations. The result verifies this method can ensure smoothness of interpolating spline curve and preserve original shape characters. The surface quality interpolated by B-spline is higher than by line and by circle arc. The algorithm is benefit to increasing the surface form precision of workpiece during ultra-precision machining.

  11. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Lens-Related Eye Infections Mar 01, 2017 New Technology Helps the Legally Blind Be More Independent Oct ... easy answer, and neither one considers long-term impacts. Phakic Intraocular Lenses for Nearsightedness FEB 27, 2017 ...

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ...

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... 2016 More Eye Health News Studies Look at Effects of Marijuana on Vision FEB 28, 2017 By ...

  14. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Healthy Contact Lens Use May 31, 2016 Is El Niño Making Your Allergies Worse? May 16, 2016 ... Number: * Email: * Enter code: * Message: Thank you Your feedback has been sent.

  15. A Spectral Representation for Spin-Weighted Spheroidal Wave Operators with Complex Aspherical Parameter

    CERN Document Server

    Finster, Felix

    2015-01-01

    A family of spectral decompositions of the spin-weighted spheroidal wave operator is constructed for complex aspherical parameters with bounded imaginary part. As the operator is not symmetric, its spectrum is complex and Jordan chains may appear. We prove uniform upper bounds for the length of the Jordan chains and the norms of the idempotent operators mapping onto the invariant subspaces. The completeness of the spectral decomposition is proven.

  16. Gradient-index ophthalmic lens design and polymer material studies

    Science.gov (United States)

    Fischer, David Joel

    Unifocal ophthalmic lenses are conventionally designed using homogeneous glass or plastic materials and aspheric surfaces. The desired power and aberration correction are provided by selection of surface shape and refractive index. This thesis studies the design of ophthalmic lenses utilizing gradient-index (GRIN) materials for both the optical power and aberration control. This is done using geometrical optical theory and ray-tracing simulations. Progressive addition lenses (PALS) are vision correction lenses with a continuous change in power used to treat presbyopia. The power variation is typically located in the lower half of the lens. Progressive addition lenses are currently made with aspheric surfaces to achieve the focal power transition and aberration control. These surfaces have at most, mirror symmetry about the vertical axis. The possible design of progressive addition lenses with GRIN materials has not been well studied. This thesis studies PALS and identifies how gradient-index materials can be used to provide both the power progression and aberration control. The optical theory for rotationally symmetric and asymmetric power additions is given. Analytical and numerical methods for calculating the index profile are used, and the results examined using ray-tracing simulations. The theory developed for ophthalmic lenses is applied to the design of GRIN axicon. This is the first GRIN axicon manufactured, and is fabricated using ion-exchanged GRIN glass. Experimental measurements of its performance are compared and found to match theoretical predictions. This demonstrates the generality of the theory developed: it may be applied to non-visual applications, and even to non-imaging applications. Realistic implementation of GRIN technology to ophthalmic application requires the fabrication of large scale refractive index gradients in polymer material systems. The methyl-methacrylate/styrene copolymer system is studied to develop an empirical model of its

  17. Early clinical outcome with a new monofocal microincision intraocular lens.

    Science.gov (United States)

    Toygar, Baha; Yabas Kiziloglu, Ozge; Toygar, Okan; Hacimustafaoglu, Ali Murat

    2016-10-01

    The purpose of this study was to evaluate the early visual and refractive outcomes of a new aspheric monofocal microincision intraocular lens (IOL). This retrospective case series included eyes of patients who underwent implantation of a microincision IOL following 1.8 mm manual coaxial microincision cataract surgery and who attended regular postoperative follow-up visits on the first week and first, third, and sixth months. The postoperative uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction and predictability, intraoperative and postoperative complications, posterior capsule opacification (PCO), IOL centration, and surgically induced astigmatism (SIA) were evaluated. Sixty-three eyes of 38 patients ranging in age from 51 to 86 were included in the study. The mean preoperative BCVA was 0.52 ± 0.42 logMAR. At the postoperative sixth month, the mean postoperative UCVA and BCVA were 0.12 ± 0.11 and 0.01 ± 0.03 logMAR, respectively. The mean postoperative spherical equivalent refraction (SER) was -0.30 ± 0.49 D. The SER was within ± 1.00 D of the attempted correction in 95.2 % of the eyes. The mean SIA measured with vector analysis was 0.45 ± 0.28 D. Mild PCO was observed in 9 eyes (14.7 %) with none requiring Nd:Yag laser capsulotomy. On centration analysis, the IOL was found to be 0.26 mm on average to the supero-nasal position. The aspheric microincision IOL was safely implanted and provided satisfactory visual and refractive outcomes in the early postoperative period.

  18. Higher order aberration comparison between two aspherical intraocular lenses: MC6125AS and Akreos advanced optics

    Institute of Scientific and Technical Information of China (English)

    Mohammad; Taher; Rajabi; Sara; Korouji; Mahgol; Farjadnia; Mohammad; Naderan; Mohammad; Bagher; Rajabi; Bahram; Khosravi; Seyed; Mehdi; Tabatabaie

    2015-01-01

    AIM: To compare higher order aberrations in two aspherical intraocular lenses(IOLs): Akreos advanced optics(AO) and Dr. Schmidt Microcrystalline 6125 aspheric anterior surface(MC6125AS) with each other. METHODS: Forty eyes of 39 patients underwent phacoemulsification and Akreos AO and MC6125 AS were implanted in their eyes in a random manner. Three months post-operatively, higher order aberrations including spherical aberration, coma aberration, and total aberrations were measured and compared.RESULTS: The total aberration was 0.24±0.17 in eyes with Dr. Schmidt and 0.20 ±0.01 in eyes with Akreos AO(P =0.361). The mean of coma aberration was 0.17 ±0.21 and 0.09 ±0.86 in Dr. Schmidt and Akreos lenses,respectively(P =0.825). Total spherical aberration was almost the same in both groups(mean: 0.05, P =0.933).Best corrected visual acuity in Akreos AO(0.10±0.68) and Dr. Schmidt(0.09±0.67) did not differ significantly(P =0.700). CONCLUSION: There is no statistically significant difference in the higher order aberrations between these two aspherical lenses.

  19. Phase-locked-loop interferometry applied to aspheric testing with a computer-stored compensator.

    Science.gov (United States)

    Servin, M; Malacara, D; Rodriguez-Vera, R

    1994-05-01

    A recently developed technique for continuous-phase determination of interferograms with a digital phase-locked loop (PLL) is applied to the null testing of aspheres. Although this PLL demodulating scheme is also a synchronous or direct interferometric technique, the separate unwrapping process is not explicitly required. The unwrapping and the phase-detection processes are achieved simultaneously within the PLL. The proposed method uses a computer-generated holographic compensator. The holographic compensator does not need to be printed out by any means; it is calculated and used from the computer. This computer-stored compensator is used as the reference signal to phase demodulate a sample interferogram obtained from the asphere being tested. Consequently the demodulated phase contains information about the wave-front departures from the ideal computer-stored aspheric interferogram. Wave-front differences of ~ 1 λ are handled easily by the proposed PLL scheme. The maximum recorded frequency in the template's interferogram as well as in the sampled interferogram are assumed to be below the Nyquist frequency.

  20. New trends in intraocular lens imaging

    Science.gov (United States)

    Millán, María S.; Alba-Bueno, Francisco; Vega, Fidel

    2011-08-01

    As a result of modern technological advances, cataract surgery can be seen as not only a rehabilitative operation, but a customized procedure to compensate for important sources of image degradation in the visual system of a patient, such as defocus and some aberrations. With the development of new materials, instruments and surgical techniques in ophthalmology, great progress has been achieved in the imaging capability of a pseudophakic eye implanted with an intraocular lens (IOL). From the very beginning, optical design has played an essential role in this progress. New IOL designs need, on the one hand, theoretical eye models able to predict optical imaging performance and on the other hand, testing methods, verification through in vitro and in vivo measurements, and clinical validation. The implant of an IOL requires a precise biometry of the eye, a prior calculation from physiological data, and an accurate position inside the eye. Otherwise, the effects of IOL calculation errors or misplacements degrade the image very quickly. The incorporation of wavefront aberrometry into clinical ophthalmology practice has motivated new designs of IOLs to compensate for high order aberrations in some extent. Thus, for instance, IOLs with an aspheric design have the potential to improve optical performance and contrast sensitivity by reducing the positive spherical aberration of human cornea. Monofocal IOLs cause a complete loss of accommodation that requires further correction for either distance or near vision. Multifocal IOLs address this limitation using the principle of simultaneous vision. Some multifocal IOLs include a diffractive zone that covers the aperture in part or totally. Reduced image contrast and undesired visual phenomena, such as halos and glare, have been associated to the performance of multifocal IOLs. Based on a different principle, accommodating IOLs rely on the effort of the ciliary body to increase the effective power of the optical system of the

  1. 一种塑料非球面门镜光学系统的设计%Optical system design for plastic aspherical doorscope

    Institute of Scientific and Technical Information of China (English)

    吴福田

    2001-01-01

    介绍了一种塑料非球面门镜的设计原理及方法。 把门镜视为逆向伽俐略系统来确定外形尺 寸参数;仔细选取系统的光阑位置,选取二次曲面的系数及二次曲面的位置,可以校正系统 的参差及像散。设计的门镜比现有的多种专利门镜结构简单、成像清晰。 其视场中心像质 达到了人眼明视距离处的极限分辨率。%This paper presents the design principle and method of an optical system for pla stic aspherical doorscope. The dimension parameters are determined by viewing t h e lens as an inverse Galileo system. The coma aberation and astigmation are rec t ified through carefully selecting the position of aperture stop and the paramete rs of the quadratic surface. Compared with the methods in the available patents , design result shows that structure is simpler and imaging is clearer. The imag e quality can reach the limit of resolution at the least distance of distinct vis ion of 250 mm.

  2. Thin Lens Ray Tracing.

    Science.gov (United States)

    Gatland, Ian R.

    2002-01-01

    Proposes a ray tracing approach to thin lens analysis based on a vector form of Snell's law for paraxial rays as an alternative to the usual approach in introductory physics courses. The ray tracing approach accommodates skew rays and thus provides a complete analysis. (Author/KHR)

  3. Corneal topography with conical null-screen for non-symmetric aspheric corneas

    Science.gov (United States)

    Armengol-Cruz, Victor de Emanuel; Osorio-Infante, Arturo I.; Campos-García, Manuel; Cossio-Guerrero, Cesar; Díaz-Uribe, José Rufino

    2016-09-01

    In this work, we will present some improvements to the conical null-screen based corneal topographer, for testing aspheric surfaces without rotational symmetry. We present the formulae to design the conical null-screen in such a way that the image on the CCD is a perfect array of spots; departures from this geometry are due to deformation or misalignment of the surface. Additionally, we will explain how to improve the algorithms to find the normals of corneal surface. Finally, we will evaluate the topography of a spherical surface.

  4. On-axis reverse Hartmann test in aspheric optical surface test with the optical flat calibration

    Science.gov (United States)

    Xia, Zhengzheng; Hui, Mei; Zhao, Zhu; Liu, Ming; Dong, Liquan; Liu, Xiaohua; Kong, Lingqin; Zhao, Yuejin

    2016-09-01

    The Reverse Hartmann test is developed rapidly, robustly, and accurately in measuring precision aspheric surface. The onaxis design provides better control of the astigmatism in the test. We use an on-axis Hartmann test in reverse to measure the aspheric optical mirrors. In the configuration, the LCD with a light pattern on the screen illuminates to the tested surface, and a 2μm-thick pellicle beam splitter is employed to obtain the coaxial light model. An optical flat with 1/20λ surface precision is used to calibrate the rays which pass through the external pinhole and image at the detector, and the data are processed to obtain the direction vectors of arbitrary reflected rays. The surface gradients are determined by the spatial equations of incident and reflected rays which have been calibrated. The shape of surface is finally reconstructed by Zernike polynomial fitting. The experiments include measuring a 76.2mm off-axis parabolic mirror and a 76.2mm spherical mirror. The experimental results show coaxial reverse Hartmann test system may allow for accurate measurements with uncertainties in the micrometer range using cost-effective equipments.

  5. Precision molding of advanced glass optics: innovative production technology for lens arrays and free form optics

    Science.gov (United States)

    Pongs, Guido; Bresseler, Bernd; Bergs, Thomas; Menke, Gert

    2012-10-01

    Today isothermal precision molding of imaging glass optics has become a widely applied and integrated production technology in the optical industry. Especially in consumer electronics (e.g. digital cameras, mobile phones, Blu-ray) a lot of optical systems contain rotationally symmetrical aspherical lenses produced by precision glass molding. But due to higher demands on complexity and miniaturization of optical elements the established process chain for precision glass molding is not sufficient enough. Wafer based molding processes for glass optics manufacturing become more and more interesting for mobile phone applications. Also cylindrical lens arrays can be used in high power laser systems. The usage of unsymmetrical free-form optics allows an increase of efficiency in optical laser systems. Aixtooling is working on different aspects in the fields of mold manufacturing technologies and molding processes for extremely high complex optical components. In terms of array molding technologies, Aixtooling has developed a manufacturing technology for the ultra-precision machining of carbide molds together with European partners. The development covers the machining of multi lens arrays as well as cylindrical lens arrays. The biggest challenge is the molding of complex free-form optics having no symmetrical axis. A comprehensive CAD/CAM data management along the entire process chain is essential to reach high accuracies on the molded lenses. Within a national funded project Aixtooling is working on a consistent data handling procedure in the process chain for precision molding of free-form optics.

  6. The study about forming high-precision optical lens minimalized sinuous error structures for designed surface

    Science.gov (United States)

    Katahira, Yu; Fukuta, Masahiko; Katsuki, Masahide; Momochi, Takeshi; Yamamoto, Yoshihiro

    2016-09-01

    Recently, it has been required to improve qualities of aspherical lenses mounted on camera units. Optical lenses in highvolume production generally are applied with molding process using cemented carbide or Ni-P coated steel, which can be selected from lens material such as glass and plastic. Additionally it can be obtained high quality of the cut or ground surface on mold due to developments of different mold product technologies. As results, it can be less than 100nmPV as form-error and 1nmRa as surface roughness in molds. Furthermore it comes to need higher quality, not only formerror( PV) and surface roughness(Ra) but also other surface characteristics. For instance, it can be caused distorted shapes at imaging by middle spatial frequency undulations on the lens surface. In this study, we made focus on several types of sinuous structures, which can be classified into form errors for designed surface and deteriorate optical system performances. And it was obtained mold product processes minimalizing undulations on the surface. In the report, it was mentioned about the analyzing process by using PSD so as to evaluate micro undulations on the machined surface quantitatively. In addition, it was mentioned that the grinding process with circumferential velocity control was effective for large aperture lenses fabrication and could minimalize undulations appeared on outer area of the machined surface, and mentioned about the optical glass lens molding process by using the high precision press machine.

  7. Injection molding lens metrology using software configurable optical test system

    Science.gov (United States)

    Zhan, Cheng; Cheng, Dewen; Wang, Shanshan; Wang, Yongtian

    2016-10-01

    Optical plastic lens produced by injection molding machine possesses numerous advantages of light quality, impact resistance, low cost, etc. The measuring methods in the optical shop are mainly interferometry, profile meter. However, these instruments are not only expensive, but also difficult to alignment. The software configurable optical test system (SCOTS) is based on the geometry of the fringe refection and phase measuring deflectometry method (PMD), which can be used to measure large diameter mirror, aspheric and freeform surface rapidly, robustly, and accurately. In addition to the conventional phase shifting method, we propose another data collection method called as dots matrix projection. We also use the Zernike polynomials to correct the camera distortion. This polynomials fitting mapping distortion method has not only simple operation, but also high conversion precision. We simulate this test system to measure the concave surface using CODE V and MATLAB. The simulation results show that the dots matrix projection method has high accuracy and SCOTS has important significance for on-line detection in optical shop.

  8. Multi-Dimensional Simulations for Early Phase Spectra of Aspherical Hypernovae: SN 1998bw and Off-Axis Hypernovae

    CERN Document Server

    Tanaka, Masaomi; Mazzali, Paolo A; Nomoto, Ken'ichi

    2007-01-01

    Early phase optical spectra of aspherical jet-like supernovae (SNe) are presented. We focus on energetic core-collapse SNe, or hypernovae. Based on hydrodynamic and nucleosynthetic models, radiative transfer in SN atmosphere is solved with a multi-dimensional Monte-Carlo radiative transfer code, SAMURAI. Since the luminosity is boosted in the jet direction, the temperature there is higher than in the equatorial plane by ~ 2,000 K. This causes anisotropic ionization in the ejecta. Emergent spectra are different depending on viewing angle, reflecting both aspherical abundance distribution and anisotropic ionization. Spectra computed with an aspherical explosion model with kinetic energy 20 x 10^{51} ergs are compatible with those of the Type Ic SN 1998bw if ~ 10-20% of the synthesized metals are mixed out to higher velocities. The simulations enable us to predict the properties of off-axis hypernovae. Even if an aspherical hypernova explosion is observed from the side, it should show hypernova-like spectra but ...

  9. Automated synthesis of both the topology and numerical parameters for seven patented optical lens systems using genetic programming

    Science.gov (United States)

    Jones, Lee W.; Al-Sakran, Sameer H.; Koza, John R.

    2005-08-01

    This paper describes how genetic programming was used as an automated invention machine to synthesize both the topology and numerical parameters for seven previously patented optical lens systems, including one aspherical system and one issued in the 21st-century. Two of the evolved optical lens systems infringe the claims of the patents and the others are novel solutions that satisfy the design goals stated in the patent. The automatic synthesis was done "from scratch"--that is, without starting from a pre-existing good design and without pre-specifying the number of lenses, the topological layout of the lenses, or the numerical parameters of the lenses. Genetic programming is a form of evolutionary computation used to automatically solve problems. It starts from a high-level statement of what needs to be done and progressively breeds a population of candidate individuals over many generations using the principle of Darwinian natural selection and genetic recombination. The paper describes how genetic programming created eyepieces that duplicated the functionality of seven previously patented lens systems. The seven designs were created in a substantially similar and routine way, suggesting that the use of genetic programming in the automated design of both the topology and numerical parameters for optical lens systems may have widespread utility.

  10. Error compensation in computer generated hologram-based form testing of aspheres.

    Science.gov (United States)

    Stuerwald, Stephan

    2014-12-10

    Computer-generated holograms (CGHs) are used relatively often to test aspheric surfaces in the case of medium and high lot sizes. Until now differently modified measurement setups for optical form testing interferometry have been presented, like subaperture stitching interferometry and scanning interferometry. In contrast, for testing low to medium lot sizes in research and development, a variety of other tactile and nontactile measurement methods have been developed. In the case of CGH-based interferometric form testing, measurement deviations in the region of several tens of nanometers typically occur. Deviations arise especially due to a nonperfect alignment of the asphere relative to the testing wavefront. Therefore, the null test is user- and adjustment-dependent, which results in insufficient repeatability and reproducibility of the form errors. When adjusting a CGH, an operator usually performs a minimization of the spatial frequency of the fringe pattern. An adjustment to the ideal position, however, often cannot be performed with sufficient precision by the operator as the position of minimum spatial fringe density is often not unique, which also depends on the asphere. Thus, the scientific and technical objectives of this paper comprise the development of a simulation-based approach to explain and quantify typical experimental errors due to misalignment of the specimen toward a CGH in an optical form testing measurement system. A further step is the programming of an iterative method to realize a virtual optimized realignment of the system on the basis of Zernike polynomial decomposition, which should allow for the calculation of the measured form for an ideal alignment and thus a careful subtraction of a typical alignment-based form error. To validate the simulation-based findings, a series of systematic experiments is performed with a recently developed hexapod positioning system in order to allow an exact and reproducible positioning of the optical CGH

  11. LASER INDUCED THERMAL LENS EFFECT

    Institute of Scientific and Technical Information of China (English)

    沈俊; 黄孟才; 江景云; 施教芳

    1991-01-01

    The thermal lens effect has emerged in recent years as a novel ,highly sensitive tool for the study of the very weak molecular absorption of light energy,This paper discusses the theory and technique of the thermal lens measurement.Some opplications of the thermal lens measurement are described.A mode-mismatched dual-beam thermal lens experimental arragement with a modulated probe beam ,designed by the authors.for trace analysis is presented,and its detection limit was found to be 4.1×10-7 for Cu(Ⅱ) in ethanol and 80 mW excitation power.

  12. Retina projection using curved lens arrays

    Science.gov (United States)

    Yen, Hao-Ren; Su, Guo-Dung J.

    2016-09-01

    In this paper, we propose a multi-channel imaging system which combines the principles of an insect's compound eye and optical cluster eye. The system consists of two curved structure lens arrays with different pitches. Both of them have the same curvature and the radiuses of the lenses in the arrays are optimized to focus rays on the retina. The optical axes of different channels are tilted to each other in order to reduce the optical system volume and transmit a wide field of view. Each channel of an array of multiple optical system transfers only a part of the field of view. Each partial image passes through each channel and stitches together on the retina to reconstruct a complete image. In order to simulate the image stitching, we also build an eye model. The thickness from the panel to the last surface of lens group is less than 25mm. The panel size is designed to be 4 inch which is the scale of eyeglass. The system can provide a large field of view about 150 degrees which is much wider than the commercial products. By using the 3D printer, we can make a model of lens array to achieve our design.

  13. Physics of electrostatic lens

    Science.gov (United States)

    1981-09-01

    The purpose of this program was to study the physics of the ion-energy boosting electrostatic lens for collective ion acceleration in the Luce diode. Extensive work was done in preparation for experiments on the PI Pulserad 1150. Analytic work was done on the orbit of protons in a mass spectrometer and a copper stack for nuclear activation analysis of proton energy spectrum has been designed. Unfortunately, a parallel program which would provide the Luce diode for the collective ion acceleration experiment never materialized. As a result no experiments were actually performed on the Pulserad 1150.

  14. Wide-Spectrum Microscope with a Long Working Distance Aspherical Objective Based on Obscuration Constraint

    Directory of Open Access Journals (Sweden)

    Weibo Wang

    2016-11-01

    Full Text Available We present an approach for an initial configuration design based on obscuration constraint and on-axis Taylor series expansion to realize the design of long working distance microscope (numerical aperture (NA = 0.13 and working distance (WD = 525 mm with a low obscuration aspherical Schwarzschild objective in wide-spectrum imaging (λ = 400–900 nm. Experiments of the testing on the resolution target and inspection on United States Air Force (USAF resolution chart and a line charge-coupled device (CCD (pixel size of 14 μm × 56 μm with different wavelength light sources (λ = 480 nm, 550 nm, 660 nm, 850 nm were implemented to verify the validity of the proposed method.

  15. Differences between real and predicted corneal shapes after aspherical corneal ablation

    Science.gov (United States)

    Anera, Rosario G.; Villa, César; Jiménez, José R.; Gutiérrez, Ramón; Jiménez del Barco, Luis

    2005-07-01

    We study the differences between real and expected corneal shapes, using an aspherical ablation algorithm with a known equation and avoiding the limitation imposed by most studies of refractive surgery in which the ablation equations are not known. We have calculated the theoretical corneal shape predicted by this algorithm, comparing this shape with the real corneal topography. The results indicate that the deviations that appear in the corneal shape are significant for visual performance and for the correction of eye aberrations. If we include in this analysis the effect of reflection losses and nonnormal incidence on the cornea, we can reduce corneal differences, but they will remain significant. These results confirm that it is essential to minimize corneal differences to achieve effective correction in refractive surgery.

  16. Stray, swing and scatter: angular momentum evolution of orbits and streams in aspherical potentials

    CERN Document Server

    Erkal, Denis; Belokurov, Vasily

    2016-01-01

    In aspherical potentials orbital planes continuously evolve. The gravitational torques impel the angular momentum vector to precess, that is to slowly stray around the symmetry axis, and nutate, i.e. swing up and down periodically in the perpendicular direction. This familiar orbital pole motion - if detected and measured - can reveal the shape of the underlying gravitational potential, the quantity only crudely gauged in the Galaxy so far. Here we demonstrate that the debris poles of stellar tidal streams show a very similar straying and swinging behavior, and give analytic expressions to link the amplitude and the frequency of the pole evolution to the flattening of the dark matter distribution. Most importantly, we explain how the differential orbital plane precession leads to the broadening of the stream and show that streams on polar orbits ought to scatter faster. We provide expressions for the stream width evolution as a function of the axisymmetric potential flattening and the angle from the symmetry ...

  17. Aspherical rotating dust dynamics for GIADA experiment in the coma of 67P/Churyumov- Gerasimenko

    Science.gov (United States)

    Ivanovski, S.; Zakharov, V.; Della Corte, V.; Lucarelli, F.; Crifo, J.-F.; Rotundi, A.; Fulle, M.

    2014-04-01

    The recent advances of the 3D+t cometary aspherical dust model [1, 2] have been used for studying the dust dynamics in the circumnuclear coma of the comet 67P/Churyumov-Gerasimenko (67P/C-G). This model will be used for analysis of the forthcoming in-situ dust data collected by GIADA (Grain Impact Analyzer and Dust Accumulator) [3] on board of the ESA ROSETTA probe. In the present research we study dust grain motion driven by the aerodynamic and gravitational forces and discuss the influence of dust grain's shape. We show the differences in dust grain velocities owing to the grain shape, initial orientation and rotation. The outcomes of the model are used to forecast by means of GIPSI [4] the dust distribution seen by GIADA at some of the ROSETTA operational phases.

  18. [Intraocular lens implantation in developmental lens disorders in children].

    Science.gov (United States)

    Kanigowska, Krystyna; Grałek, Mirosława; Kepa, Beata; Chipczyńska, Barbara

    2009-01-01

    The pediatric cataract surgery in eyes with developmental disorders, stay with still considerable challenge. At children, the lasting vision development extorts necessity quick settlement of refraction defect formed after operation. The intraocular lens old boy with cataract in microspherophakia and 12 years old boy with cataract in lens with coloboma. One-piece flexible and rigid PMMA intraocular lens was placed with success at posterior chamber without scleral fixations and without using capsular tension ring in this cases. After 3 years of observation there were no decentration or dislocation of intraocular lens in both children. Authors concluded that in some cases posterior chamber intraocular lens implantation despite defective zonular or capsular support, can make up the effective method of surgical treatment without risk of early dislocation.

  19. Advancements in transformation optics-enabled gradient-index lens design

    Science.gov (United States)

    Campbell, Sawyer D.; Brocker, Donovan E.; Nagar, Jogender; Easum, John A.; Werner, Douglas H.; Werner, Pingjuan L.

    2015-09-01

    Transformation Optics (TO) provides the mathematical framework for representing the behavior of electromagnetic radiation in a given geometry by "transforming" it to an alternative, usually more desirable, geometry through an appropriate mapping of the constituent material parameters. Using a quasi-conformal mapping, the restrictions on the required material parameters can be relaxed allowing isotropic inhomogeneous all-dielectric materials to be employed. This approach has led to the development of a new and powerful design tool for gradient-index (GRIN) optical systems. Using TO, aspherical lenses can be transformed to simpler spherical and flat geometries or even rotationally-asymmetric shapes which result in true 3D GRIN profiles. TO can also potentially be extended to collapse an entire lens system into a representative GRIN profile thus reducing its physical dimensions while retaining the optical performance of the original system. However, dispersion effects of the constituent materials often limit the bandwidth of metamaterial and TO structures thus restricting their potential applicability. Nonetheless, with the proper pairing of GRIN profile and lens geometry to a given material system, chromatic aberrations can be minimized. To aid in the GRIN construction, we employ advanced multi-objective optimization algorithms which allow the designer to explicitly view the trade-offs between all design objectives such as RMS spot size, field-of-view (FOV), lens thickness, 𝛥𝑛, and focal drift due to chromatic aberrations. We present an overview of our TO-enabled GRIN lens design process and analysis techniques while demonstrating designs which minimize the presence of mono- and poly-chromatic aberrations and discuss their requisite material systems.

  20. The Deep Lens Survey

    CERN Document Server

    Wittman, D; Dell'Antonio, I P; Becker, A C; Margoniner, V E; Cohen, J; Norman, D; Loomba, D; Squires, G; Wilson, G; Stubbs, C; Hennawi, J F; Spergel, D N; Boeshaar, P C; Clocchiatti, A; Hamuy, M; Bernstein, G; González, A; Guhathakurta, R; Hu, W; Seljak, U; Zaritsky, D

    2002-01-01

    The Deep Lens Survey (DLS) is a deep BVRz' imaging survey of seven 2x2 degree fields, with all data to be made public. The primary scientific driver is weak gravitational lensing, but the survey is also designed to enable a wide array of other astrophysical investigations. A unique feature of this survey is the search for transient phenomena. We subtract multiple exposures of a field, detect differences, classify, and release transients on the Web within about an hour of observation. Here we summarize the scientific goals of the DLS, field and filter selection, observing techniques and current status, data reduction, data products and release, and transient detections. Finally, we discuss some lessons which might apply to future large surveys such as LSST.

  1. Accurate testing of aspheric surfaces using the transport of intensity equation by properly selecting the defocusing distance.

    Science.gov (United States)

    Soltani, Peyman; Darudi, Ahmad; Nehmetallah, George; Moradi, Ali Reza; Amiri, Javad

    2016-12-10

    In the last decade, the transport of intensity has been increasingly used in microscopy, wavefront sensing, and metrology. In this study, we verify by simulation and experiment the use of the transport of intensity equation (TIE) in the accurate testing of optical aspheric surfaces. Guided by simulation results and assuming that the experimental setup parameters and the conic constants are known, one can estimate an appropriate defocusing distance Δz that leads to an accurate solution of the TIE. In this paper, this method is verified through the construction of a non-nulled experiment for testing the 2D profile of an aspheric surface. The theoretical method and experimental results are compared to validate the results. Finally, to validate the TIE methodology, the phase distribution obtained by TIE is compared with the phase distribution obtained by a Shack-Hartmann sensor.

  2. Manufacturing progress of production of high aspherical axis and off-axis astronomical and space optics for the last decade

    Science.gov (United States)

    Semenov, Aleksandr P.; Abdulkadyrov, Magomed A.; Belousov, Sergey P.; Ignatov, Aleksandr N.; Patrikeev, Vladimir E.

    2016-10-01

    The article describes the technology of production of astronomical and space mirrors from Astrositall CO-115M including its properties and stability of these properties over time and presents the results of material long-term testing. The article also describes computer-controlled methods of large-scaled optics production and testing, including high aspherical, off-axis and thin mirrors, using the examples of production of mirrors at JSC LZOS.

  3. Investigation into photostability of soybean oils by thermal lens spectroscopy.

    Science.gov (United States)

    Savi, E L; Malacarne, L C; Baesso, M L; Pintro, P T M; Croge, C; Shen, J; Astrath, N G C

    2015-06-15

    Assessment of photochemical stability is essential for evaluating quality and the shelf life of vegetable oils, which are very important aspects of marketing and human health. Most of conventional methods used to investigate oxidative stability requires long time experimental procedures with high consumption of chemical inputs for the preparation or extraction of sample compounds. In this work we propose a time-resolved thermal lens method to analyze photostability of edible oils by quantitative measurement of photoreaction cross-section. An all-numerical routine is employed to solve a complex theoretical problem involving photochemical reaction, thermal lens effect, and mass diffusion during local laser excitation. The photostability of pure oil and oils with natural and synthetic antioxidants is investigated. The thermal lens results are compared with those obtained by conventional methods, and a complete set of physical properties of the samples is presented.

  4. Investigation into photostability of soybean oils by thermal lens spectroscopy

    Science.gov (United States)

    Savi, E. L.; Malacarne, L. C.; Baesso, M. L.; Pintro, P. T. M.; Croge, C.; Shen, J.; Astrath, N. G. C.

    2015-06-01

    Assessment of photochemical stability is essential for evaluating quality and the shelf life of vegetable oils, which are very important aspects of marketing and human health. Most of conventional methods used to investigate oxidative stability requires long time experimental procedures with high consumption of chemical inputs for the preparation or extraction of sample compounds. In this work we propose a time-resolved thermal lens method to analyze photostability of edible oils by quantitative measurement of photoreaction cross-section. An all-numerical routine is employed to solve a complex theoretical problem involving photochemical reaction, thermal lens effect, and mass diffusion during local laser excitation. The photostability of pure oil and oils with natural and synthetic antioxidants is investigated. The thermal lens results are compared with those obtained by conventional methods, and a complete set of physical properties of the samples is presented.

  5. Transferring Lens Prescriptions Between Lens-Design Programs

    Science.gov (United States)

    Stacy, John E.; Wooley, Laura; Carlin, Brian

    1989-01-01

    Optical Lens Prescription Data Formatter computer program enables user to transfer complicated lens prescriptions quickly and easily from one major optical-design program to another and back again. One can take advantage of inherent strength of either program. Programs are ACCOS V from Scientific Calculations, Inc., of Fishers, NY, and CODE V from Optical Research Associates of Pasadena, CA. VAX version written in FORTRAN.

  6. Phakic Intraocular lens- a review

    OpenAIRE

    Cruz, Francisco Miguel

    2015-01-01

    Introduction: Intraocular refractive procedures with the implantation of a Phakic Intraocular lens have become a safe efficient and predictable alternative for treating high ametropias when the use of corneal photoablative procedures is not possible. The implantation of Phakic intraocular lens preservs the accomodative function,is a reversable refractive procedure, with minimal induction of higher order aberrations compaed with corneal photoablative procedures. Methods: An analytical review o...

  7. Ascorbate in the ocular lens

    OpenAIRE

    Mody, Vino C. Jr

    2006-01-01

    Purpose: First, we intended to establish a method for sample preparation for measurement of ascorbate in whole rat and guinea pig lenses utilizing ultrafiltration and high performance liquid chromatography with ultraviolet radiation detection. Then, we aimed to investigate whether, in the albino rat, lens ascorbate concentration depends on solid dietary intake. Finally, we investigated if, in the pigmented guinea pig, lens ascorbate concentration may be elevated with drinkin...

  8. Gravitational lens surveys with LOFAR

    CERN Document Server

    Wucknitz, O

    2008-01-01

    Deep surveys planned as a Key Science Project of LOFAR provide completely new opportunities for gravitational lens searches. For the first time do large-scale surveys reach the resolution required for a direct selection of lens candidates using morphological criteria. We briefly describe the strategies that we will use to exploit this potential. The long baselines of an international E-LOFAR are essential for this project.

  9. A course in lens design

    CERN Document Server

    Velzel, Chris

    2014-01-01

    A Course in Lens Design is an instruction in the design of image-forming optical systems. It teaches how a satisfactory design can be obtained in a straightforward way. Theory is limited to a minimum, and used to support the practical design work. The book introduces geometrical optics, optical instruments and aberrations. It gives a description of the process of lens design and of the strategies used in this process. Half of its content is devoted to the design of sixteen types of lenses, described in detail from beginning to end. This book is different from most other books on lens design because it stresses the importance of the initial phases of the design process: (paraxial) lay-out and (thin-lens) pre-design. The argument for this change of accent is that in these phases much information can be obtained about the properties of the lens to be designed. This information can be used in later phases of the design. This makes A Course in Lens Design a useful self-study book, and a suitable basis for an intro...

  10. 影响激光驱动器注入镜组特性的误差因素分析%AnaIysis of Error Factor Impacting on the Performance of Laser-driver Injection Compound Lens

    Institute of Scientific and Technical Information of China (English)

    柏占伟; 谢志江; 袁晓东

    2014-01-01

    研究了惯性约束大功率激光聚变驱动器注入镜组特性影响因素,分析表明透镜的几何尺寸公差、透镜装配公差和镜组在线安装公差等因素对镜组焦距公差、焦斑分布、波像差方面的特性影响较大。针对影响镜组特性的主要因素,建立了镜组特性影响分析的相关数学模型,并基于MatIab和Zemax软件平台对模型进行模拟计算,结果表明数学模型可以保证镜组特性需要的制造、安装公差。%During the study Of aII kinds Of tOIerance infIuencing factOrs On the perfOrmance Of injectiOn cOmpOund Iens made Of high pOwer Iaser inertiaI cOnfinement fusiOn drive,anaIysis shOws that geOmetry dimensiOn tOIerance Of the Iens,Iens assembIy tOIerance and cOmpOund Iens have a significant effect On the perfOmance Of cOmpOund Iens fOcaI Iength tOIerance, fOcaI spOt pOsitiOn and wave aberratiOn. AccOrding tO the main infIuencing factOrs,reIated perfOrmance mathematicaI mOdeIs are set up. The mOdeIs are simuIated and the resuIts Of simuIatiOn are anaIyzed based On the sOftware pIatfOrm Of MatIab and Zemax. The manufacturing and instaIIatiOn tOIerance ensuring the perfOrmance are aIsO determined based On the simuIatiOn resuIts and tOIerance Of cOmpOund Iens.

  11. Research on controlling middle spatial frequency error of high gradient precise aspheric by pitch tool

    Science.gov (United States)

    Wang, Jia; Hou, Xi; Wan, Yongjian; Shi, Chunyan; Zhong, Xianyun

    2016-09-01

    Extreme optical fabrication projects known as EUV and X-ray optic systems, which are representative of today's advanced optical manufacturing technology level, have special requirements for the optical surface quality. In synchroton radiation (SR) beamlines, mirrors of high shape accuracy is always used in grazing incidence. In nanolithograph systems, middle spatial frequency errors always lead to small-angle scattering or flare that reduces the contrast of the image. The slope error is defined for a given horizontal length, the increase or decrease in form error at the end point relative to the starting point is measured. The quality of reflective optical elements can be described by their deviation from ideal shape at different spatial frequencies. Usually one distinguishes between the figure error, the low spatial error part ranging from aperture length to 1mm frequencies, and the mid-high spatial error part from 1mm to 1 μm and from1 μm to some 10 nm spatial frequencies, respectively. Firstly, this paper will disscuss the relationship between slope error and middle spatial frequency error, which both describe the optical surface error along with the form profile. Then, experimental researches will be conducted on a high gradient precise aspheric with pitch tool, which aim to restraining the middle spatial frequency error.

  12. Stray, swing and scatter: angular momentum evolution of orbits and streams in aspherical potentials

    Science.gov (United States)

    Erkal, Denis; Sanders, Jason L.; Belokurov, Vasily

    2016-09-01

    In aspherical potentials orbital planes continuously evolve. The gravitational torques impel the angular momentum vector to precess, that is to slowly stray around the symmetry axis, and nutate, i.e. swing up and down periodically in the perpendicular direction. This familiar orbital pole motion - if detected and measured - can reveal the shape of the underlying gravitational potential, the quantity only crudely gauged in the Galaxy so far. Here we demonstrate that the debris poles of stellar tidal streams show a very similar straying and swinging behaviour, and give analytic expressions to link the amplitude and the frequency of the pole evolution to the flattening of the dark matter distribution. While these results are derived for near-circular orbits, we show they are also valid for eccentric orbits. Most importantly, we explain how the differential orbital plane precession leads to the broadening of the stream and show that streams on polar orbits ought to scatter faster. We provide expressions for the stream width evolution as a function of the axisymmetric potential flattening and the angle from the symmetry plane and prove that our models are in good agreement with streams produced in N-body simulations. Interestingly, the same intuition applies to streams whose progenitors are on short- or long-axis loops in a triaxial potential. Finally, we present a compilation of the Galactic cold stream data, and discuss how the simple picture developed here, along with stream modelling, can be used to constrain the symmetry axes and flattening of the Milky Way.

  13. The 2010 IODC lens design problem: the green lens

    Science.gov (United States)

    Juergens, Richard C.

    2010-08-01

    The lens design problem for the 2010 IODC is to design a 100 mm focal length lens in which every optical surface has the same radius of curvature, positive or negative, or is plano. The lens is used monochromatically at 532 nm and is made of only Schott N-BK7 glass. The goal of the problem is to maximize the product of the semi-field of view and the entrance pupil diameter while holding the distortion to within +/-5% and the RMS wavefront error to <= 0.07 wave within the field of view. There were 37 entries from eight different countries. Four different commercial lens design programs were used, along with two custom, in-house programs. The number of lens elements in the entries ranged from 3 to 64. The overall length of the lenses varied from 105 mm to 3.6 km. The winning entry had an entrance pupil diameter of 81.3 mm and a semi-field of view of 43.5° for a merit function product of 3537.

  14. Electrowetting liquid lens array on curved substrates for wide field of view image sensor

    Science.gov (United States)

    Bang, Yousung; Lee, Muyoung; Won, Yong Hyub

    2016-03-01

    In this research, electrowetting liquid lens array on curved substrates is developed for wide field of view image sensor. In the conventional image sensing system, this lens array is usually in the form of solid state. However, in this state, the lens array which is similar to insect-like compound eyes in nature has several limitations such as degradation of image quality and narrow field of view because it cannot adjust focal length of lens. For implementation of the more enhanced system, the curved array of lenses based on electrowetting effect is developed in this paper, which can adjust focal length of lens. The fabrication of curved lens array is conducted upon the several steps, including chamber fabrication, electrode & dielectric layer deposition, liquid injection, and encapsulation. As constituent materials, IZO coated convex glass, UV epoxy (NOA 68), DI water, and dodecane are used. The number of lenses on the fabricated panel is 23 by 23 and each lens has 1mm aperture with 1.6mm pitch between adjacent lenses. When the voltage is applied on the device, it is observed that each lens is changed from concave state to convex state. From the unique optical characteristics of curved array of liquid lenses such as controllable focal length and wide field of view, we can expect that it has potential applications in various fields such as medical diagnostics, surveillance systems, and light field photography.

  15. Fabrication of polycrystalline diamond refractive X-ray lens by femtosecond laser processing

    Energy Technology Data Exchange (ETDEWEB)

    Kononenko, T.V.; Ralchenko, V.G.; Ashkinazi, E.E.; Konov, V.I. [General Physics Institute of Russian Academy of Sciences, Moscow (Russian Federation); National Research Nuclear University ' ' MEPhI' ' , Moscow (Russian Federation); Polikarpov, M.; Ershov, P. [Immanuel Kant Baltic Federal University, Functional Nanomaterials, Kaliningrad (Russian Federation); Kuznetsov, S.; Yunkin, V. [Institute of Microelectronics Technology RAS, Chernogolovka, Moscow region (Russian Federation); Snigireva, I. [European Synchrotron Radiation Facility, Grenoble (France)

    2016-03-15

    X-ray planar compound refractive lenses were fabricated from a polycrystalline diamond plate grown by chemical vapor deposition, by precise through cutting with femtosecond laser pulses. The lens geometry and the surface morphology were investigated with optical and scanning electron microscopy, while the material structure modification was analyzed by Raman spectroscopy. The results of the preliminary lens test at 9.25-keV X-rays are presented. (orig.)

  16. Planar immersion lens with metasurfaces

    CERN Document Server

    Ho, John S; Tanabe, Yuji; Yeh, Alexander J; Fan, Shanhui; Poon, Ada S Y

    2015-01-01

    The solid immersion lens is a powerful optical tool that allows light entering material from air or vacuum to focus to a spot much smaller than the free-space wavelength. Conventionally, however, they rely on semispherical topographies and are non-planar and bulky, which limits their integration in many applications. Recently, there has been considerable interest in using planar structures, referred to as metasurfaces, to construct flat optical components for manipulating light in unusual ways. Here, we propose and demonstrate the concept of a planar immersion lens based on metasurfaces. The resulting planar device, when placed near an interface between air and dielectric material, can focus electromagnetic radiation incident from air to a spot in material smaller than the free-space wavelength. As an experimental demonstration, we fabricate an ultrathin and flexible microwave lens and further show that it achieves wireless energy transfer in material mimicking biological tissue.

  17. Tinting of intraocular lens implants

    Energy Technology Data Exchange (ETDEWEB)

    Zigman, S.

    1982-06-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users.

  18. International rigid contact lens prescribing.

    Science.gov (United States)

    Efron, Nathan; Morgan, Philip B; Helland, Magne; Itoi, Motozumi; Jones, Deborah; Nichols, Jason J; van der Worp, Eef; Woods, Craig A

    2010-06-01

    Rigid lenses have been fitted less since the introduction of soft lenses nearly 40 years ago. Data that we have gathered from annual contact lens fitting surveys conducted in Australia, Canada, Japan, the Netherlands, Norway, the UK and the USA between 2000 and 2008 facilitate an accurate characterization of the pattern of the decline of rigid lens fitting during the first decade of this century. There is a trend for rigid lenses to be utilized primarily for refitting those patients who are already successful rigid lens wearers-most typically older females being refit with higher Dk materials. Rigid lenses are generally fitted on a full-time basis (four or more days of wear per week) without a planned replacement schedule. Orthokeratology is especially popular in the Netherlands, but is seldom prescribed in the other countries surveyed.

  19. Algebraic Lens Distortion Model Estimation

    Directory of Open Access Journals (Sweden)

    Luis Alvarez

    2010-07-01

    Full Text Available A very important property of the usual pinhole model for camera projection is that 3D lines in the scene are projected to 2D lines. Unfortunately, wide-angle lenses (specially low-cost lenses may introduce a strong barrel distortion, which makes the usual pinhole model fail. Lens distortion models try to correct such distortion. We propose an algebraic approach to the estimation of the lens distortion parameters based on the rectification of lines in the image. Using the proposed method, the lens distortion parameters are obtained by minimizing a 4 total-degree polynomial in several variables. We perform numerical experiments using calibration patterns and real scenes to show the performance of the proposed method.

  20. Corneal Epithelial Remodeling and Its Effect on Corneal Asphericity after Transepithelial Photorefractive Keratectomy for Myopia

    Directory of Open Access Journals (Sweden)

    Jie Hou

    2016-01-01

    Full Text Available Purpose. To evaluate the changes in epithelial thickness profile following transepithelial photorefractive keratectomy (T-PRK for myopia and to investigate the effect of epithelial remodeling on corneal asphericity. Methods. Forty-four patients (44 right eyes who underwent T-PRK were retrospectively evaluated. Epithelial thickness was measured using spectral-domain optical coherence tomography at different corneal zones (central, 2 mm; paracentral, 2–5 mm; and mid-peripheral, 5-6 mm preoperatively and at 1 week and 1, 3, and 6 months postoperatively. The correlation between the changes in corneal epithelial thickness (ΔCET and postoperative Q-value changes (ΔQ was analyzed 6 months postoperatively. Results. Epithelial thickness at 6 months showed a negative meniscus-like lenticular pattern with less central thickening, which increased progressively toward the mid-periphery (3.69±4.2, 5.19±3.8, and 6.23±3.9 μm at the center, paracenter, and mid-periphery, resp., P<0.01. A significant positive relationship was observed between epithelial thickening and ΔQ 6 months postoperatively (r=0.438, 0.580, and 0.504, resp., P<0.01. Conclusions. Significant epithelial thickening was observed after T-PRK and showed a lenticular change with more thickening mid-peripherally, resulting in increased oblateness postoperatively. Epithelial remodeling may modify the epithelial thickness profile after surface ablation refractive surgery for myopia.

  1. Asphericity of pretherapeutic tumour FDG uptake provides independent prognostic value in head-and-neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Apostolova, Ivayla; Steffen, Ingo G. [Charite University Medical Center, Department of Nuclear Medicine, Berlin (Germany); Otto-von-Guericke University Clinic Magdeburg, Department of Radiology and Nuclear Medicine, Magdeburg (Germany); Wedel, Florian; Buchert, Ralph; Brenner, Winfried [Charite University Medical Center, Department of Nuclear Medicine, Berlin (Germany); Lougovski, Alexandr; Hofheinz, Frank [Helmholtz Center Dresden Rossendorf, Institute of Radiopharmaceutical Cancer Research, Dresden (Germany); Marnitz, Simone [Charite University Medical Center, Department of Radiooncology, Berlin (Germany); Derlin, Thorsten [University Medical Center Hamburg-Eppendorf, Department of Radiology, Hamburg (Germany); Amthauer, Holger [Otto-von-Guericke University Clinic Magdeburg, Department of Radiology and Nuclear Medicine, Magdeburg (Germany)

    2014-09-15

    To propose a novel measure, namely the 'asphericity' (ASP), of spatial irregularity of FDG uptake in the primary tumour as a prognostic marker in head-and-neck cancer. PET/CT was performed in 52 patients (first presentation, n = 36; recurrence, n = 16). The primary tumour was segmented based on thresholding at the volume-reproducible intensity threshold after subtraction of the local background. ASP was used to characterise the deviation of the tumour's shape from sphere symmetry. Tumour stage, tumour localisation, lymph node metastases, distant metastases, SUV{sub max}, SUV{sub mean}, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) were also considered. The association of overall (OAS) and progression-free survival (PFS) with these parameters was analysed. Cox regression revealed high SUV{sub max} [hazard ratio (HR) = 4.4/7.4], MTV (HR = 4.6/5.7), TLG (HR = 4.8/8.9) and ASP (HR = 7.8/7.4) as significant predictors with respect to PFS/OAS in case of first tumour manifestation. The combination of high MTV and ASP showed very high HRs of 22.7 for PFS and 13.2 for OAS. In case of recurrence, MTV (HR = 3.7) and the combination of MTV/ASP (HR = 4.2) were significant predictors of PFS. ASP of pretherapeutic FDG uptake in the primary tumour improves the prediction of tumour progression in head-and-neck cancer at first tumour presentation. (orig.)

  2. Correlations between the alpha angle and femoral head asphericity: Implications and recommendations for the diagnosis of cam femoroacetabular impingement

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Michael D., E-mail: michael.harris@utah.edu [Department of Orthopaedics, Department of Bioengineering, University of Utah, 590 Wakara Way A-100, Salt Lake City, UT 84108 (United States); Kapron, Ashley L., E-mail: ashley.kapron@utah.edu [Department of Orthopaedics, Department of Bioengineering, University of Utah, 590 Wakara Way A-100, Salt Lake City, UT 84108 (United States); Peters, Christopher L., E-mail: chris.peters@hsc.utah.edu [Department of Orthopaedics, 590 Wakara Way A-100, Salt Lake City, UT 84108 (United States); Anderson, Andrew E., E-mail: andrew.anderson@hsc.utah.edu [Department of Orthopaedics, Department of Bioengineering, Department of Physical Therapy, Scientific Computing and Imaging Institute, University of Utah, 590 Wakara Way A-100, Salt Lake City, UT 84108 (United States)

    2014-05-15

    Objective: To determine the strength of common radiographic and radial CT views for measuring true femoral head asphericity. Patients and methods: In 15 patients with cam femoroacetabular impingement (FAI) and 15 controls, alpha angles were measured by two observers using radial CT (0°, 30°, 60°, 90°) and digitally reconstructed radiographs (DRRs) for the: anterior–posterior (AP), standing frog-leg lateral, 45° Dunn with neutral rotation, 45° Dunn with 40° external rotation, and cross-table lateral views. A DRR validation study was performed. Alpha angles were compared between groups. Maximum deviation from a sphere of each subject was obtained from a previous study. Alpha angles from each view were correlated with maximum deviation. Results: There were no significant differences between alpha angles measured on radiographs and the corresponding DRRs (p = 0.72). Alpha angles were significantly greater in patients for all views (p ≤ 0.002). Alpha angles from the 45° Dunn with 40° external rotation, cross-table lateral, and 60° radial views had the strongest correlations with maximum deviation (r = 0.831; r = 0.823; r = 0.808, respectively). The AP view had the weakest correlation (r = 0.358). Conclusion: DRRs were a validated means to simulate hip radiographs. The 45° Dunn with 40° external rotation, cross-table lateral, and 60° radial views best visualized femoral asphericity. Although commonly used, the AP view did not visualize cam deformities well. Overall, the magnitude of the alpha angle may not be indicative of the size of the deformity. Thus, 3D reconstructions and measurements of asphericity could improve the diagnosis of cam FAI.

  3. Spectroscopic evidence of large aspherical β-NAT particles involved in denitrification in the December 2011 Arctic stratosphere

    Science.gov (United States)

    Woiwode, Wolfgang; Höpfner, Michael; Bi, Lei; Pitts, Michael C.; Poole, Lamont R.; Oelhaf, Hermann; Molleker, Sergej; Borrmann, Stephan; Klingebiel, Marcus; Belyaev, Gennady; Ebersoldt, Andreas; Griessbach, Sabine; Grooß, Jens-Uwe; Gulde, Thomas; Krämer, Martina; Maucher, Guido; Piesch, Christof; Rolf, Christian; Sartorius, Christian; Spang, Reinhold; Orphal, Johannes

    2016-07-01

    We analyze polar stratospheric cloud (PSC) signatures in airborne MIPAS-STR (Michelson Interferometer for Passive Atmospheric Sounding - STRatospheric aircraft) observations in the spectral regions from 725 to 990 and 1150 to 1350 cm-1 under conditions suitable for the existence of nitric acid trihydrate (NAT) above northern Scandinavia on 11 December 2011. The high-resolution infrared limb emission spectra of MIPAS-STR show a characteristic "shoulder-like" signature in the spectral region around 820 cm-1, which is attributed to the ν2 symmetric deformation mode of NO3- in β-NAT. Using radiative transfer calculations involving Mie and T-Matrix methods, the spectral signatures of spherical and aspherical particles are simulated. The simulations are constrained using collocated in situ particle measurements. Simulations assuming highly aspherical spheroids with aspect ratios (AR) of 0.1 or 10.0 and a lognormal particle mode with a mode radius of 4.8 µm reproduce the observed spectra to a high degree. A smaller lognormal mode with a mode radius of 2.0 µm, which is also taken into account, plays only a minor role. Within the scenarios analyzed, the best overall agreement is found for elongated spheroids with AR = 0.1. Simulations of spherical particles and spheroids with AR = 0.5 and 2.0 return results very similar to each other and do not allow us to reproduce the signature around 820 cm-1. The observed "shoulder-like" signature is explained by the combination of the absorption/emission and scattering characteristics of large highly aspherical β-NAT particles. The size distribution supported by our results corresponds to ˜ 9 ppbv of gas-phase equivalent HNO3 at the flight altitude of ˜ 18.5 km. The results are compared with the size distributions derived from the in situ observations, a corresponding Chemical Lagrangian Model of the Stratosphere (CLaMS) simulation, and excess gas-phase HNO3 observed in a nitrification layer directly below the observed PSC. The

  4. Revival of The Stalled Core-Collapse Supernova Shock Triggered by Precollapse Asphericity in the Progenitor Star

    CERN Document Server

    Couch, Sean M

    2013-01-01

    Multi-dimensional simulations of advanced nuclear burning stages of massive stars suggest that the Si/O layers of presupernova stars harbor large deviations from the spherical symmetry typically assumed for presupernova stellar structure. We carry out three-dimensional core-collapse supernova simulations with and without aspherical velocity perturbations to assess their potential impact on the supernova hydrodynamics in the stalled shock phase. Our results show that realistic perturbations can qualitatively alter the postbounce evolution, triggering an explosion in a model that fails to explode without them. This finding underlines the need for a multi-dimensional treatment of the presupernova stage of stellar evolution.

  5. Panoramic lens designed with transformation optics

    Science.gov (United States)

    Wang, Huaping; Deng, Yangyang; Zheng, Bin; Li, Rujiang; Jiang, Yuyu; Dehdashti, Shahram; Xu, Zhiwei; Chen, Hongsheng

    2017-01-01

    The panoramic lens is a special kind of lens, which is applied to observe full view. In this letter, we theoretically present a panoramic lens (PL) using transformation optics method. The lens is designed with inhomogeneous and anisotropic constitutive parameters, which has the ability to gather light from all directions and confine light within the visual angle of observer. Simulation results validate our theoretical design.

  6. SimpLens: Interactive gravitational lensing simulator

    Science.gov (United States)

    Saha, Prasenjit; Williams, Liliya L. R.

    2016-06-01

    SimpLens illustrates some of the theoretical ideas important in gravitational lensing in an interactive way. After setting parameters for elliptical mass distribution and external mass, SimpLens displays the mass profile and source position, the lens potential and image locations, and indicate the image magnifications and contours of virtual light-travel time. A lens profile can be made shallower or steeper with little change in the image positions and with only total magnification affected.

  7. Test on large convex aspherical mirror by subaperture stitching interferometry%大口径凸非球面反射镜子孔径拼接检测

    Institute of Scientific and Technical Information of China (English)

    王孝坤

    2013-01-01

    In order to obtain the figure error of the whole large convex aspherical mirror, a new method for testing large convex asphere by subaperture stitching and interferometry so called SSI was proposed. A perfect sphere mirror was used as the reference surface, the phase distribution of each subaperture could be measured by the digital wavefront interferometer, and the full surface map could be calculated by stitching several subapertures. The basic principle and theory of SSI were studied, the stitching process and prototype for test of large aspheres were devised and developed, and the setup of SSI for measuring of large aspherical surface was designed and manufactured. A convex SiC asphere mirror with the aperture of 260 mm was tested by SSI with 9 subapertures. For the validation, the aspheric mirror was also measured by null compensation, the difference of PV and RMS error was 0.043 and 0.021 , respectively ( is 632.8 nm). It provides an another accurate testing method for aspherical surface especially for large convex aspherical mirror.%  为了获得大口径凸非球面反射镜全口径的面形,提出了利用子孔径拼接检测大口径凸非球面的新方法.利用干涉仪标准球面波前次干涉测定大口径镜面上各个区的相位分布,通过子孔径拼接算法即可求解得到镜面全口径面形信息.对该方法的基本理和实现步骤进行了分析和研究,建立了大口径拼接检测算法的数学模型,设计并研制了大口径反射镜拼接检验装置.结合实例对一口径为260 mm的碳化硅凸非球面反射镜进行了9个子孔径的拼接干涉测量,并将拼接检测结果与全口径面形测量结果进行对比,两种方法测量面形PV值和RMS值的偏差分别为0.043和0.021(=632.8 nm).

  8. 21 CFR 886.3600 - Intraocular lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraocular lens. 886.3600 Section 886.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3600 Intraocular lens. (a) Identification. An intraocular lens is a device made of materials...

  9. Professoren og Ålen

    DEFF Research Database (Denmark)

    Poulsen, Bo

    2016-01-01

    Biolog og havforsker Johannes Schmidt regnes for at være Danmarks mest betydningsfulde havforsker gennem tiderne. Hans mange forskningsbaserede jordomsejlinger bragte ham til eksotiske egne og til opdagelsen af adskillige nye dyrearter. Dog blev særligt ålen og dens gydepladser et hovedfokus for ...

  10. The Ultrawideband Leaky Lens Antenna

    NARCIS (Netherlands)

    Bruni, S.; Neto, A.; Marliani, F.

    2007-01-01

    A novel directive and nondispersive antenna is presented: the ultrawideband (UWB) leaky lens. It is based on the broad band Cherenkov radiation occurring at a slot printed between different infinite homogeneous dielectrics. The first part of the paper presents the antenna concept and the UWB design.

  11. Professoren og Ålen

    DEFF Research Database (Denmark)

    Poulsen, Bo

    2016-01-01

    Biolog og havforsker Johannes Schmidt regnes for at være Danmarks mest betydningsfulde havforsker gennem tiderne. Hans mange forskningsbaserede jordomsejlinger bragte ham til eksotiske egne og til opdagelsen af adskillige nye dyrearter. Dog blev særligt ålen og dens gydepladser et hovedfokus...

  12. Estimation of the hybrid lens parameters through rigid gas permeable lens fitting

    OpenAIRE

    Hasani, Mohammadali; Hashemi, Hassan; Jafarzadehpur, Ebrahim; Yekta, Abbas Ali; Dadbin, Nooshin; khabazkhoob, Mehdi

    2016-01-01

    Purpose To estimate the fitting parameters of the hybrid contact lens in patients with corneal ectasia using the rigid gas permeable (RGP) lens. Methods Thirty-four eyes with corneal ectasia were evaluated in this study. The patients were examined once with the RGP lens and once with the hybrid contact lens. The relationship between the base curvature of the RGP and the vault of the hybrid lens and the correlation between their powers were analyzed. Results We found a linear relationship betw...

  13. Lens stem cells may reside outside the lens capsule: an hypothesis

    Directory of Open Access Journals (Sweden)

    Meyer Rita A

    2007-06-01

    Full Text Available Abstract In this paper, we consider the ocular lens in the context of contemporary developments in biological ideas. We attempt to reconcile lens biology with stem cell concepts and a dearth of lens tumors. Historically, the lens has been viewed as a closed system, in which cells at the periphery of the lens epithelium differentiate into fiber cells. Theoretical considerations led us to question whether the intracapsular lens is indeed self-contained. Since stem cells generate tumors and the lens does not naturally develop tumors, we reasoned that lens stem cells may not be present within the capsule. We hypothesize that lens stem cells reside outside the lens capsule, in the nearby ciliary body. Our ideas challenge the existing lens biology paradigm. We begin our discussion with lens background information, in order to describe our lens stem cell hypothesis in the context of published data. Then we present the ciliary body as a possible source for lens stem cells, and conclude by comparing the ocular lens with the corneal epithelium.

  14. Dynamics of aspherical dust grains in a cometary atmosphere: I. axially symmetric grains in a spherically symmetric atmosphere

    Science.gov (United States)

    Ivanovski, S. L.; Zakharov, V. V.; Della Corte, V.; Crifo, J.-F.; Rotundi, A.; Fulle, M.

    2017-01-01

    In-situ measurements of individual dust grain parameters in the immediate vicinity of a cometary nucleus are being carried by the Rosetta spacecraft at comet 67P/Churyumov-Gerasimenko. For the interpretations of these observational data, a model of dust grain motion as realistic as possible is requested. In particular, the results of the Stardust mission and analysis of samples of interplanetary dust have shown that these particles are highly aspherical, which should be taken into account in any credible model. The aim of the present work is to study the dynamics of ellipsoidal shape particles with various aspect ratios introduced in a spherically symmetric expanding gas flow and to reveal the possible differences in dynamics between spherical and aspherical particles. Their translational and rotational motion under influence of the gravity and of the aerodynamic force and torque is numerically integrated in a wide range of physical parameters values including those of comet 67P/Churyumov-Gerasimenko. The main distinctions of the dynamics of spherical and ellipsoidal particles are discussed. The aerodynamic characteristics of the ellipsoidal particles, and examples of their translational and rotational motion in the postulated gas flow are presented.

  15. Ground-based and orbital off-axis aspherized grating imager-spectrographs: ISARD-OMP and OSIRIS-ODIN

    Science.gov (United States)

    Lemaitre, Gerard R.; Richardson, Eric H.

    1998-07-01

    Progress in Active Optics Methods has led to the invention and production of blazed aspherical gratings. These developments use jointly 'vase form' submasters and a two-stage replication technique. It has been shown that the use of aspherized gratings greatly minimizes the number of optical surfaces. This improves the optical throughput of astronomical spectrographs and has a capability of correcting camera mirror aberrations up to f/1.2. With respect to refractive designs, the full achromaticity in correcting mirror aberrations by constant line spacing reflective gratings allows much broader spectral coverages -- hereafter [(lambda) (lambda) ] approximately equals 2 octaves. In addition, and also due to a full reflective design, such instruments provide quasi- constant spectral dispersions and are distortion free. These latter features increase the accuracy in the data reduction process (sky substraction, etc. ...), and are particularly convenient in the multi-aperture mode. Recent developments in this field are presented with imager-spectrograph ISARD, dedicated to the Cassegrain focus of the 2m Bernard Lyot Telescope at Pic-du-Midi Observatory for faint object studies in the optical domain [320 - 1200 nm], and with spectrograph OSIRIS, to be launched in a ODIN orbital mission in 1998 and built by the Canadian Space Agency for studies in the spectral range [295 - 800 nm].

  16. Contact mechanics and elastohydrodynamic lubrication in a novel metal-on-metal hip implant with an aspherical bearing surface.

    Science.gov (United States)

    Meng, Qingen; Gao, Leiming; Liu, Feng; Yang, Peiran; Fisher, John; Jin, Zhongmin

    2010-03-22

    Diameter and diametral clearance of the bearing surfaces of metal-on-metal hip implants and structural supports have been recognised as key factors to reduce the dry contact and hydrodynamic pressures and improve lubrication performance. On the other hand, application of aspherical bearing surfaces can also significantly affect the contact mechanics and lubrication performance by changing the radius of the curvature of a bearing surface and consequently improving the conformity between the head and the cup. In this study, a novel metal-on-metal hip implant employing a specific aspherical bearing surface, Alpharabola, as the acetabular surface was investigated for both contact mechanics and elastohydrodynamic lubrication under steady-state conditions. When compared with conventional spherical bearing surfaces, a more uniform pressure distribution and a thicker lubricant film thickness within the loaded conjunction were predicted for this novel Alpharabola hip implant. The effects of the geometric parameters of this novel acetabular surface on the pressure distribution and lubricant thickness were investigated. A significant increase in the predicted lubricant film thickness and a significant decrease in the dry contact and hydrodynamic pressures were found with appropriate combinations of these geometric parameters, compared with the spherical bearing surface.

  17. Transferable aspherical atom model refinement of protein and DNA structures against ultrahigh-resolution X-ray data.

    Science.gov (United States)

    Malinska, Maura; Dauter, Zbigniew

    2016-06-01

    In contrast to the independent-atom model (IAM), in which all atoms are assumed to be spherical and neutral, the transferable aspherical atom model (TAAM) takes into account the deformed valence charge density resulting from chemical bond formation and the presence of lone electron pairs. Both models can be used to refine small and large molecules, e.g. proteins and nucleic acids, against ultrahigh-resolution X-ray diffraction data. The University at Buffalo theoretical databank of aspherical pseudo-atoms has been used in the refinement of an oligopeptide, of Z-DNA hexamer and dodecamer duplexes, and of bovine trypsin. The application of the TAAM to these data improves the quality of the electron-density maps and the visibility of H atoms. It also lowers the conventional R factors and improves the atomic displacement parameters and the results of the Hirshfeld rigid-bond test. An additional advantage is that the transferred charge density allows the estimation of Coulombic interaction energy and electrostatic potential.

  18. Modern lens antennas for communications engineering

    CERN Document Server

    Thornton, John

    2012-01-01

    The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

  19. The Sloan Lens ACS Survey. VI: Discovery and analysis of a double Einstein ring

    CERN Document Server

    Gavazzi, Raphael; Koopmans, Leon V E; Bolton, Adam S; Moustakas, Leonidas A; Burles, Scott; Marshall, Philip J

    2008-01-01

    We report the discovery of two concentric Einstein rings around the gravitational lens SDSSJ0946+1006, as part of the Sloan Lens ACS Survey. The main lens is at redshift zl=0.222, while the inner ring (1) is at zs1=0.609 and Einstein radius $Re_1=1.43\\pm0.01"$. The wider image separation ($Re_2=2.07\\pm 0.02"$) of the outer ring (2) implies that it is at higher redshift. Its detection in the F814W filter implies zs2<6.9. The configuration can be well described by a total density profile $\\rho_{tot} ~ r^-g'$ with $g'=2.00\\pm0.03$ and velocity dispersion $\\sigma_{SIE}=287\\pm5\\kms$. [...] We consider whether this configuration can be used to constrain cosmological parameters exploiting angular distance ratios entering the lens equations. Constraints for SDSSJ0946+1006, are uninteresting due to the sub-optimal lens and source redshifts. We then consider the perturbing effect of the mass associated with Ring 1 building a double lens plane compound lens model. This introduces minor changes to the mass of the main...

  20. The asphericity of the metabolic tumour volume in NSCLC: correlation with histopathology and molecular markers

    Energy Technology Data Exchange (ETDEWEB)

    Apostolova, Ivayla; Ego, Kilian; Steffen, Ingo G. [University Hospital, Otto-von-Guericke University Magdeburg, Clinic of Radiology and Nuclear Medicine, Magdeburg (Germany); Buchert, Ralph [University Medicine Charite, Clinic of Nuclear Medicine, Berlin (Germany); Wertzel, Heinz; Achenbach, H.J. [Lung Clinic Lostau GmbH, Lostau (Germany); Riedel, Sandra; Schreiber, Jens [University Hospital, Otto-von-Guericke University Magdeburg, Clinic of Pneumology, Magdeburg (Germany); Schultz, Meinald [Institute of Pathology Stendal, Stendal (Germany); Furth, Christian; Amthauer, Holger [University Hospital, Otto-von-Guericke University Magdeburg, Clinic of Radiology and Nuclear Medicine, Magdeburg (Germany); University Medicine Charite, Clinic of Nuclear Medicine, Berlin (Germany); Derlin, Thorsten [Hannover Medical School, Department of Nuclear Medicine, Hannover (Germany); Hofheinz, Frank [Helmholtz-Center Dresden-Rossendorf, Dresden (Germany); Kalinski, Thomas [University Hospital Magdeburg, Otto-von-Guericke University Magdeburg, Institute for Pathology, Magdeburg (Germany); Institute for Pathology Lademannbogen, Hamburg (Germany)

    2016-12-15

    Asphericity (ASP) is a tumour shape descriptor based on the PET image. It quantitates the deviation from spherical of the shape of the metabolic tumour volume (MTV). In order to identify its biological correlates, we investigated the relationship between ASP and clinically relevant histopathological and molecular signatures in non-small-cell lung cancer (NSCLC). The study included 83 consecutive patients (18 women, aged 66.4 ± 8.9 years) with newly diagnosed NSCLC in whom PET/CT with {sup 18}F-FDG had been performed prior to therapy. Primary tumour resection specimens and core biopsies were used for basic histopathology and determination of the Ki-67 proliferation index. EGFR status, VEGF, p53 and ALK expression were obtained in a subgroup of 44 patients. The FDG PET images of the primary tumours were delineated using an automatic algorithm based on adaptive thresholding taking into account local background. In addition to ASP, SUVmax, MTV and some further descriptors of shape and intratumour heterogeneity were assessed as semiquantitative PET measures. SUVmax, MTV and ASP were associated with pathological T stage (Kruskal-Wallis, p = 0.001, p < 0.0005 and p < 0.0005, respectively) and N stage (p = 0.017, p = 0.003 and p = 0.002, respectively). Only ASP was associated with M stage (p = 0.026). SUVmax, MTV and ASP were correlated with Ki-67 index (Spearman's rho = 0.326/p = 0.003, rho = 0.302/p = 0.006 and rho = 0.271/p = 0.015, respectively). The latter correlations were considerably stronger in adenocarcinomas than in squamous cell carcinomas. ASP, but not SUVmax or MTV, showed a tendency for a significant association with the extent of VEGF expression (p = 0.058). In multivariate Cox regression analysis, ASP (p < 0.0005) and the presence of distant metastases (p = 0.023) were significantly associated with progression-free survival. ASP (p = 0.006), the presence of distant metastases (p = 0.010), and Ki-67 index (p = 0.062) were significantly associated with

  1. Conjunctival impression cytology in contact lens wearers.

    Directory of Open Access Journals (Sweden)

    Simon Priya

    2002-01-01

    Full Text Available PURPOSE: To evaluate the cytological changes in conjunctiva following regular contact lens wear and to determine the correlation, if any, between severity of cytological alteration and symptoms related to contact lens wear. METHODS: One hundred eyes (50 normal asymptomatic subjects who served as a control group were studied by conjunctival impression cytology (CIC. These subjects were fitted with rigid gas permeable (RGP or soft contact lenses and were followed up at the end of 3 and 6 months. At each follow-up visit the CIC was repeated. A filter paper with the impression specimen was stained with periodic acid schiff (PAS and haematoxylin stain to study goblet cell loss. Papanicolaou stain was done to study squamous metaplasia. The cytological changes were graded using the system described by Natadisastra et al. RESULTS: Severity of cytological changes increased with the duration of contact lens wear (P = 0.00001. At the end of 6 months, 60% of symptomatic eyes wearing soft contact lens and RGP lens showed abnormal CIC changes. None of the asymptomatic RGP contact lens wearing eyes showed abnormal CIC changes whereas 33.4% of the asymptomatic soft contact lens wearing eyes showed abnormal CIC changes (P = 0.033. Epithelial changes occurred within 3-6 months of contact lens fitting. CONCLUSION: Severity of cytological changes increased with duration of lens wear (P = 0.00001. Prevalence and severity of cytological alteration is more in symptomatic contact lens wearers. Soft contact lens wearers although asymptomatic showed severe CIC changes.

  2. Study on Titanium Nitride Film Modified for Intraocular Lens

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective:To study the characteristics of the intraocular lens using ion beam sputtering depositing titanium nitride thin film on the intraocular lens(IOLs).Methods:To deposite titanium nitride thin film on the top of intraocular lens by ion beam sputtering depositing.We analyzed the surface morphology of intraocular lens through SEM and AFM.We detected intraocular lens resolution through the measurement of intraocular lens.Biocompatibility of intraocular lens is preliminary evaluated in this test.Results:T...

  3. Lens Coupled Quantum Cascade Laser

    Science.gov (United States)

    Hu, Qing (Inventor); Lee, Alan Wei Min (Inventor)

    2013-01-01

    Terahertz quantum cascade (QC) devices are disclosed that can operate, e.g., in a range of about 1 THz to about 10 THz. In some embodiments, QC lasers are disclosed in which an optical element (e.g., a lens) is coupled to an output facet of the laser's active region to enhance coupling of the lasing radiation from the active region to an external environment. In other embodiments, terahertz amplifier and tunable terahertz QC lasers are disclosed.

  4. Fresnel Lens with Embedded Vortices

    Directory of Open Access Journals (Sweden)

    Sunil Vyas

    2012-01-01

    Full Text Available Vortices of different charges are embedded in a wavefront that has quadratic phase variation, and the intensity distribution near the focal plane is studied. This method may be useful in realizing complicated beam profiles. We have experimentally demonstrated the generation of vortex arrays having integer as well as fractional topological charges that produce different intensity profiles at the focal plane. The phase variation realized on a spatial light modulator (SLM acts as a Fresnel lens with embedded vortices.

  5. Corneal biomechanics after rigid gas permeable contact lens wear in keratoconus eyes

    Institute of Scientific and Technical Information of China (English)

    Fereshteh Shokrollahzadeh; Hassan Hashemi; Ebrahim Jafarzadehpur; Ali Mirzajani; Mehdi Khabazkhoob; Soheila Asgari

    2016-01-01

    Background:Evaluation of corneal biomechanical properties 3 months after using rigid gas permeable (RGP) contact lenses in keratoconus. Methods: In this prospective trial study, cases were 32 keratoconic eyes with no history of RGP lens wear. All eyes were examined with the Ocular Response Analyzer (ORA) and the Corneal Visualization Scheimpflug Technology (CORVIS-ST) to measure corneal hysteresis (CH), corneal resistance factor (CRF), deformation amplitude (DA), applanation velocity (AV) 1 and 2, applanation length (AL) 1 and 2, and peak distance before and 3 months after iftting aspheric RGP lenses. The effect of the correlation between contralateral eyes and maximum keratometry were controlled for in the analysis. Results were compared using repeated measures analysis of covariance. Results:At 3 months, neither the increases in mean CH (0.14±2.77 mmHg, P=0.789), CRF (0.41±4.35 mmHg, P=0.612), AV1 (0.03±0.17 m/s, P=0.301), AV2 (0.11±0.59 m/s, P=0.299), AL1 (0.44±1.56 m/s, P=0.118), AL2 (1.16±5.06 m/s, P=0.211), and peak distance (0.19±1.29 m/s, P=0.409), nor the decrease in mean DA (0.03±0.17 mm, P=0.402) was statistically signiifcant. Conclusions: Results in our series of patients indicated that 3 months of RGP lens wear had no signiifcant impact on corneal biomechanics, and perhaps non progression of keratoconus. Therefore, RGP lenses can be regarded safe and appropriate in keratoconic patients.

  6. Evolution of a pre and post lens tear film with a contact lens

    Science.gov (United States)

    Gerhart, Matthew; Anderson, Daniel

    2012-11-01

    The work is the development, implementation, and analysis of a two-dimensional tear film model including a porous contact lens. The geometry of the problem is: a pre-lens layer that is a thin tear film between the outside air and contact lens, a contact lens that is a rigid but movable porous substrate, and a post-lens layer that is a thin film layer between the contact lens and the cornea. We are looking at short and long term behavior of the evolution of the thin film in the pre-lens layer coupled with the porous layer and the thin squeeze film in the post-lens layer. We model the different behaviors that arise as the Darcy number, evaporation effects, and boundary flux conditions change.

  7. Asphericity in the Fermi Surface and Fermi Energy of Na-K,Na-Rb and Na-Cs Binary Alloys

    Institute of Scientific and Technical Information of China (English)

    MinalH.Patel; A.M.Vora; 等

    2002-01-01

    Detailed theoretical investigations into asphericity in the Fermi surface(FS) and Fermi energy(FE) of Na1-xKx,Na1-xRbx,and Na1-xCsx binary solid solutions are carried out for the first time,The allying behavior of the K,Rb,and Cs with the Na generates the Fermi surface distortion(FSD) of bcc simple metals,The FS of Na-K,Na-Rb,and Na-Cs solid solution is a distorted sphere with the largest deviation along[110],We have found that the impact of local-field correction function on FSD is maximum at [100] point and minimum at [111] point.The exchange and correlation effect is found to suppress the value of FE.

  8. Asphericity, Interaction, and Dust in the Type II-P/II-L Supernova 2013ej in Messier 74

    CERN Document Server

    Mauerhan, Jon C; Johansson, Joel; Hu, Maokai; Fox, Ori D; Wang, Lifan; Graham, Melissa L; Filippenko, Alexei V; Shivvers, Isaac

    2016-01-01

    SN 2013ej is a well-studied core-collapse supernova (SN) that stemmed from a directly identified red supergiant (RSG) progenitor in galaxy M74. The source exhibits signs of substantial geometric asphericity, X-rays from persistent interaction with circumstellar material (CSM), thermal emission from warm dust, and a light curve that appears intermediate between supernovae of Types II-P and II-L. The proximity of this source motivates a close inspection of these physical characteristics and their potential interconnection. We present multi-epoch spectropolarimetry of SN 2013ej during the first 107 days, and deep optical spectroscopy and ultraviolet through infrared photometry past ~800 days. SN 2013ej exhibits the strongest and most persistent continuum and line polarization ever observed for a SN of its class during the recombination phase. Modeling indicates that the data are consistent with an oblate ellipsoidal photosphere, viewed nearly edge-on, and probably augmented by optical scattering from circumstell...

  9. A unified model for the spectrophotometric development of classical and recurrent novae: the role of asphericity of the ejecta

    CERN Document Server

    Shore, Steven N

    2013-01-01

    There is increasing evidence that the geometry, and not only the filling factors, of nova ejecta is important in the interpretation of their spectral and photometric developments. Ensembles of spectra and light curves have provided general typographies. This Letter suggests how these can be unified.The observed spread in the maximum magnitude - rate of decline (MMRD) relation is argued to result from the range of opening angles and inclination of the ejecta, and not only to their masses and velocities. The spectroscopic classes can be similarly explained and linked to the behavior of the light curves. The secondary maximum observed in some dust forming novae is a natural consequence of the asphericity. Neither secondary ejections nor winds are needed to explain the phenomenology. The spectrophotometric development of classical novae can be understood within a single phenomenological model with bipolar, although not jet-like, mass ejecta. High resolution spectropolarimetry will be an essential analytical tool.

  10. Lateral shear interferometry with holo shear lens

    Science.gov (United States)

    Joenathan, C.; Mohanty, R. K.; Sirohi, R. S.

    1984-12-01

    A simple method for obtaining lateral shear using holo shear lenses (HSL) has been discussed. This simple device which produces lateral shears in the orthogonal directions has been used for lens testing. The holo shear lens is placed at or near the focus of the lens to be tested. It has also been shown that HSL can be used in speckle shear interferometry as it performs both the functions of shearing and imaging.

  11. An inverse and analytic lens design method

    OpenAIRE

    Lu, Yang; Lakshminarayanan, Vasudevan

    2016-01-01

    Traditional lens design is a numerical and forward process based on ray tracing and aberration theory. This method has limitations because the initial configuration of the lens has to be specified and the aberrations of the lenses have to considered. This paper is an initial attempt to investigate an analytic and inverse lens design method, called Lagrange, to overcome these barriers. Lagrange method tries to build differential equations in terms of the system parameters and the system input ...

  12. Asphericity, Interaction, and Dust in the Type II-P/II-L Supernova 2013EJ in Messier 74

    Science.gov (United States)

    Mauerhan, Jon C.; Van Dyk, Schuyler D.; Johansson, Joel; Hu, Maokai; Fox, Ori D.; Wang, Lifan; Graham, Melissa L.; Filippenko, Alexei V.; Shivvers, Isaac

    2017-01-01

    SN 2013ej is a well-studied core-collapse supernova (SN) that stemmed from a directly identified red supergiant (RSG) progenitor in galaxy M74. The source exhibits signs of substantial geometric asphericity, X-rays from persistent interaction with circumstellar material (CSM), thermal emission from warm dust, and a light curve that appears intermediate between supernovae of Types II-P and II-L. The proximity of this source motivates a close inspection of these physical characteristics and their potential interconnection. We present multiepoch spectropolarimetry of SN 2013ej during the first 107 days and deep optical spectroscopy and ultraviolet through infrared photometry past ∼800 days. SN 2013ej exhibits the strongest and most persistent continuum and line polarization ever observed for a SN of its class during the recombination phase. Modeling indicates that the data are consistent with an oblate ellipsoidal photosphere, viewed nearly edge-on and probably augmented by optical scattering from circumstellar dust. We suggest that interaction with an equatorial distribution of CSM, perhaps the result of binary evolution, is responsible for generating the photospheric asphericity. Relatedly, our late-time optical imaging and spectroscopy show that asymmetric CSM interaction is ongoing, and the morphology of broad Hα emission from shock-excited ejecta provides additional evidence that the geometry of the interaction region is ellipsoidal. Alternatively, a prolate ellipsoidal geometry from an intrinsically bipolar explosion is also a plausible interpretation of the data but would probably require a ballistic jet of radioactive material capable of penetrating the hydrogen envelope early in the recombination phase. Finally, our latest space-based optical imaging confirms that the late interaction-powered light curve dropped below the stellar progenitor level, confirming the RSG star’s association with the explosion.

  13. Algorithm design of liquid lens inspection system

    Science.gov (United States)

    Hsieh, Lu-Lin; Wang, Chun-Chieh

    2008-08-01

    In mobile lens domain, the glass lens is often to be applied in high-resolution requirement situation; but the glass zoom lens needs to be collocated with movable machinery and voice-coil motor, which usually arises some space limits in minimum design. In high level molding component technology development, the appearance of liquid lens has become the focus of mobile phone and digital camera companies. The liquid lens sets with solid optical lens and driving circuit has replaced the original components. As a result, the volume requirement is decreased to merely 50% of the original design. Besides, with the high focus adjusting speed, low energy requirement, high durability, and low-cost manufacturing process, the liquid lens shows advantages in the competitive market. In the past, authors only need to inspect the scrape defect made by external force for the glass lens. As to the liquid lens, authors need to inspect the state of four different structural layers due to the different design and structure. In this paper, authors apply machine vision and digital image processing technology to administer inspections in the particular layer according to the needs of users. According to our experiment results, the algorithm proposed can automatically delete non-focus background, extract the region of interest, find out and analyze the defects efficiently in the particular layer. In the future, authors will combine the algorithm of the system with automatic-focus technology to implement the inside inspection based on the product inspective demands.

  14. Coculture with intraocular lens material-activated macrophages induces an inflammatory phenotype in lens epithelial cells.

    Science.gov (United States)

    Pintwala, Robert; Postnikoff, Cameron; Molladavoodi, Sara; Gorbet, Maud

    2015-03-01

    Cataracts are the leading cause of blindness worldwide, requiring surgical implantation of an intraocular lens. Despite evidence of leukocyte ingress into the postoperative lens, few studies have investigated the leukocyte response to intraocular lens materials. A novel coculture model was developed to examine macrophage activation by hydrophilic acrylic (poly(2-hydroxyethyl methacrylate)) and hydrophobic acrylic (polymethylmethacrylate) commercial intraocular lens. The human monocytic cell line THP-1 was differentiated into macrophages and cocultured with human lens epithelial cell line (HLE-B3) with or without an intraocular lens for one, two, four, or six days. Using flow cytometry and confocal microscopy, expression of the macrophage activation marker CD54 (intercellular adhesion molecule-1) and production of reactive oxygen species via the fluorogenic probe 2',7'-dichlorodihydrofluorescein diacetate were examined in macrophages. α-Smooth muscle actin, a transdifferentiation marker, was characterized in lens epithelial cells. The poly(2-hydroxyethyl methacrylate) intraocular lens prevented adhesion but induced significant macrophage activation (p intraocular lens), while the polymethylmethacrylate intraocular lens enabled adhesion and multinucleated fusion, but induced no significant activation. Coculture with either intraocular lens increased reactive oxygen species production in macrophages after one day (p intraocular lens, with hydrophilic surfaces inducing higher activation than hydrophobic surfaces. These findings provide a new method of inquiry into uveal biocompatibility, specifically through the quantification of cell-surface markers of leukocyte activation.

  15. SMILE术后角膜前表面非球面性与角膜高阶像差的关系%The correlation between corneal asphericity and higher order aberrations after SMILE surgery

    Institute of Scientific and Technical Information of China (English)

    苏小连; 王雁

    2014-01-01

    Objective To evaluate the characteristics of anterior corneal asphericity and higher order aberrations after SMILE surgery,and to analyze the correlation between them.Methods In this prospective study,41 subjects who underwent SMILE surgery were enrolled with right eyes selected for the study.The asphericity coefficient Q-value at diameters of 6,7,8 and 9 mm and total higher order aberrations (HOA),spherical aberrations (Z40),secondary spherical aberrations (Z60),vertical coma (Z3-1),horizontal coma (Z31),y-trefoil (Z3-3) and x-trefoil (Z33) of the cornea were measured before surgery and 3 months following the surgery.A paired-samples t test and Pearson correlation were used for analysis.Results All Q-values increased from negative to positive after SMILE surgery and the differences were statistically significant (t=-23.558,-26.661,-28.366,-28.788,P<0.01).Corneal HOA,Z40,Z60,Z3-1 and Z31 increased and the differences were statistically significant as well (t=-11.815,-11.813,-16.209,6.470,4.835,P<0.01).However,the change in Z3-3 or Z33 was not significant (t=0.278,-1.064,P>0.05).Among corneal higher order aberrations,a linear correlation was found between the Q-value and corneal HOA,Z40 and Z3-t before surgery (P<0.05).The change in corneal HOA and Z40 had a positive linear correlation with the Q-value at each diameter (HOA:r=0.554,0.480,0.416,0.352,P<0.05; Z40:r=0.671,0.577,0.495,0.395,P<0.05).The difference in Z3-1 had a positive linear correlation with the Q-values at diameters 6 and 7 mm (r=0.377,0.342,P<0.05).The difference in Z31 had a positive linear correlation with the Q-values at diameters 6,7 and 8 mm (r=0.436,0.385,0.316,P<0.05).No linear correlation was found between the changes in the Q-values at each diameter and those of Z3 3,Z33 or Z60 (P>0.05).There was not a linear correlation between the change in the Q-values and lens diameter (P>0.05).Lens diameter had a negative linear correlation with the changes in HOA and Z40 (r=-0

  16. Paediatric intraocular lens implants: accuracy of lens power calculations.

    Science.gov (United States)

    O'Gallagher, M K; Lagan, M A; Mulholland, C P; Parker, M; McGinnity, G; McLoone, E M

    2016-09-01

    PurposeThis study aims to evaluate the accuracy of lens prediction formulae on a paediatric population.MethodsA retrospective case-note review was undertaken of patients under 8 years old who underwent cataract surgery with primary lens implantation in a regional referral centre for paediatric ophthalmology, excluding those whose procedure was secondary to trauma. Biometric and refractive data were analysed for 43 eyes, including prediction errors (PE). Statistical measures used included mean absolute error (MAE), median absolute error (MedAE), Student's t-test and Lin's correlation coefficient.ResultsThe mean PE using the SRK-II formula was +0.96 D (range -2.47D to +2.41 D, SD 1.33 D, MAE 1.38 D, MedAE 1.55, n=15). The mean PE was smaller using SRK/T (-0.18 D, range -3.25 D to +3.95 D, SD 1.70 D, MAE 1.30 D, MedAE 1.24, n=27). We performed an analysis of the biometry data using four different formula (Hoffer Q, Holladay 1, SRK-II and SRK/T). Hoffer Q showed a smaller MedAE than other formulae but also a myopic bias.ConclusionOur clinical data suggest SRK/T was more accurate in predicting post-operative refraction in this cohort of paediatric patients undergoing cataract surgery. Hoffer Q may have improved accuracy further.

  17. Flat lens for seismic waves

    CERN Document Server

    Brule, Stephane; Guenneau, Sebastien

    2016-01-01

    A prerequisite for achieving seismic invisibility is to demonstrate the ability of civil engineers to control seismic waves with artificially structured soils. We carry out large-scale field tests with a structured soil made of a grid consisting of cylindrical and vertical holes in the ground and a low frequency artificial source (< 10 Hz). This allows the identification of a distribution of energy inside the grid, which can be interpreted as the consequence of an effective negative refraction index. Such a flat lens reminiscent of what Veselago and Pendry envisioned for light opens avenues in seismic metamaterials to counteract the most devastating components of seismic signals.

  18. Intraocular lens with accommodation capacity

    OpenAIRE

    Dorronsoro, Carlos; Alejandre, Nicolás; Bekesi, Nandor; Marcos, Susana

    2014-01-01

    Intraocular lens with accommodation capacity comprising a first optical member (1) having a dynamic optical power, to which a second optical member (2) with a fixed optical power is affixed, in such a manner that at least a central part of each of one of one of the curved surfaces (2a, 2b) of the second optical member (2) and of at least one of the surfaces (1a, 1b) of the first optical member (1) are in contact with each other, the second optical member (2) and the first optical member (1) p...

  19. Atom lens without chromatic aberrations

    CERN Document Server

    Efremov, Maxim A; Schleich, Wolfgang P

    2012-01-01

    We propose a lens for atoms with reduced chromatic aberrations and calculate its focal length and spot size. In our scheme a two-level atom interacts with a near-resonant standing light wave formed by two running waves of slightly different wave vectors, and a far-detuned running wave propagating perpendicular to the standing wave. We show that within the Raman-Nath approximation and for an adiabatically slow atom-light interaction, the phase acquired by the atom is independent of the incident atomic velocity.

  20. Cross-linking of lens crystallin proteins induced by tryptophan metabolites and metal ions

    DEFF Research Database (Denmark)

    Tweeddale, Helen J; Hawkins, Clare Louise; Janmie, Joane F

    2016-01-01

    Long-wavelength solar UV radiation is implicated in photodamage to the human eye. The human lens contains multiple tryptophan-derived compounds that have significant absorbance bands in the UVA region (λ 315-400 nm) that act as efficient physical filters for these wavelengths. The concentrations...... of many of these UV filter compounds decrease with increase in age, resulting in diminished protection, increased oxidative damage and the accumulation of modified proteins implicated in nuclear cataract formation. This damage may arise via the formation of α,β-unsaturated carbonyls from the UV filter...... compounds, adduction to lens proteins and subsequent action as photosensitizers, and/or via the reactions of redox-active transition metal ions that accumulate in aged human lenses. The latter may promote the oxidation of free, or protein-bound, o-aminophenols, such as the UV filter compounds 3...

  1. Targeting cyst wall is an effective strategy in improving the efficacy of marketed contact lens disinfecting solutions against Acanthamoeba castellanii cysts.

    Science.gov (United States)

    Abjani, Farhat; Khan, Naveed Ahmed; Yousuf, Farzana Abubakar; Siddiqui, Ruqaiyyah

    2016-06-01

    Acanthamoeba cysts are highly resistant to contact lens disinfecting solutions. Acanthamoeba cyst wall is partially made of 1,4 β-glucan (i.e., cellulose) and other complex polysaccharides making it a hardy shell that protects the resident amoeba. Here, we hypothesize that targeting the cyst wall structure in addition to antiamoebic compound would improve the efficacy of marketed contact lens disinfecting solutions. Using chlorhexidine as an antiamoebic compound and cellulase enzyme to disrupt cyst wall structure, the findings revealed that combination of both agents abolished viability of Acanthamoeba castellanii cysts and trophozoites. When tested alone, none of the agents nor contact lens disinfecting solutions completely destroyed A. castellanii cysts and trophozoites. The absence of cyst wall-degrading enzymes in marketed contact lens disinfecting solutions render them ineffective against Acanthamoeba cysts. It is concluded that the addition of cyst wall degrading molecules in contact lens disinfecting solutions will enhance their efficacy in decreasing the incidence of Acanthamoeba effectively.

  2. Contact lens intolerance: refitting with dual axis lens for corneal refractive therapy

    Science.gov (United States)

    López-López, María; Pelegrín-Sánchez, José Miguel; Sobrado-Calvo, Paloma; García-Ayuso, Diego

    2011-01-01

    Corneal refractive therapy is a non-surgical procedure whose main purpose is to improve uncorrected visual acuity during the day, without spectacles or contact lenses. We report an adult woman who shows contact lens intolerance and does not want to wear eyeglasses. We used dual axis contact lens to improve lens centration. We demonstrate a maintained unaided visual acuity during one year of treatment. In conclusion, we can consider refitting with dual axis lens for corneal refractive therapy as a non-surgical option for patients who show contact lens intolerance.

  3. Fabricating customized hydrogel contact lens

    Science.gov (United States)

    Childs, Andre; Li, Hao; Lewittes, Daniella M.; Dong, Biqin; Liu, Wenzhong; Shu, Xiao; Sun, Cheng; Zhang, Hao F.

    2016-10-01

    Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm. The Young’s modulus (1.47 MPa) and hydrophobicity (with a sessile drop contact angle of 40.5°) have also been characterized experimentally. Retinal imaging using optical coherence tomography in rats wearing our customized contact lenses has the quality comparable to the control case without the contact lens. Our method could significantly reduce the cost and the lead time for fabricating soft contact lenses with customized shapes, and benefit the laboratorial-used contact lenses in pre-clinical studies.

  4. Managing as designing with a positive lens

    NARCIS (Netherlands)

    Avital, M.; Boland, R.J.; Avital, M.; Boland, R.J.; Cooperrider, D.L.

    2007-01-01

    The role and potential contribution of a positive lens to the design of systems and organizations is the focus of this essay. The positive lens refers to an emerging perspective in the social sciences that emphasizes a positive stance toward our capacity to construct better organizations and technol

  5. Liquid lens using acoustic radiation force.

    Science.gov (United States)

    Koyama, Daisuke; Isago, Ryoichi; Nakamura, Kentaro

    2011-03-01

    A liquid lens is proposed that uses acoustic radiation force with no mechanical moving parts. It consists of a cylindrical acrylic cell filled with two immiscible liquids (degassed water and silicone oil) and a concave ultrasound transducer. The focal point of the transducer is located on the oil-water interface, which functions as a lens. The acoustic radiation force is generated when there is a difference in the acoustic energy densities of different media. An acoustic standing wave was generated in the axial direction of the lens and the variation of the shape of the oil-water interface was observed by optical coherence tomography (OCT). The lens profile can be rapidly changed by varying the acoustic radiation force from the transducer. The kinematic viscosity of silicone oil was optimized to minimize the response times of the lens. Response times of 40 and 80 ms when switching ultrasonic radiation on and off were obtained with a kinematic viscosity of 200 cSt. The path of a laser beam transmitted through the lens was calculated by ray-tracing simulations based on the experimental results obtained by OCT. The transmitted laser beam could be focused by applying an input voltage. The liquid lens could be operated as a variable-focus lens by varying the input voltage.

  6. Plasma Lens for Muon and Neutrino Beams

    Energy Technology Data Exchange (ETDEWEB)

    Kahn,S.A.; Korenev, S.; Bishai, M.; Diwan, M.; Gallardo, J.C.; Hershcovitch, A.; Johnson, B.M.

    2008-06-23

    The plasma lens is examined as an alternate to focusing horns and solenoids for use in a neutrino or muon beam facility. The plasma lens concept is based on a combined high-energy lens/target configuration. The current is fed at electrodes located upstream and downstream from the target where pion capturing is needed. The current flows primarily in the plasma, which has a lower resistivity than the target. A second plasma lens section, with an additional current feed, follows the target to provide shaping of the plasma for optimum focusing. The plasma lens is immersed in an additional solenoid magnetic field to facilitate the plasma stability. The geometry of the plasma is shaped to provide optimal pion capture. Simulations of this plasma lens system have shown a 25% higher neutrino production than the horn system. Plasma lenses have the additional advantage of negligible pion absorption and scattering by the lens material and reduced neutrino contamination during anti-neutrino running. Results of particle simulations using plasma lens will be presented.

  7. Metasurface lens: Shrinking the camera size

    Science.gov (United States)

    Sun, Cheng

    2017-01-01

    A miniaturized camera has been developed by integrating a planar metasurface lens doublet with a CMOS image sensor. The metasurface lens doublet corrects the monochromatic aberration and thus delivers nearly diffraction-limited image quality over a wide field of view.

  8. 组合非球面太阳能聚光镜的光学设计%Optical design of build-up aspherical solar concentrating mirror

    Institute of Scientific and Technical Information of China (English)

    秦华; 冯东太; 葛硕硕; 王勇

    2014-01-01

    In this paper , a build-up aspherical solar concentrating mirror and its design method are presented . It is composed of 38 pieces of revolution surfaces , and each piece of revolution surface is the part of the as-pheric surface defined by a set of specific coefficients C,a2 ,a4 ,a6 ,a8 ,a10 .According to the even aspherical e-quation and the law of reflection in vector form , the relationship between the direction vectors of rays of light reflected from the inner wall of aspheric surface and the coefficients of an aspherical equation , C,a2 ,a4 ,a6 , a8 ,a10 , has been derived .By appropriately choosing these aspherical coefficients , namely, appropriately ad-justing an aspherical surface type , the reflected light beam can have specific direction vectors , which can make the sunbeams incident on an aspherical inner wall focus on a particular area and form a small spot .Each group of specific coefficients is obtained by using particle swarm optimization algorithm .The focusing effect of the solar concentrating mirror with the specific coefficients is demonstrated by using computer simulations and proved experimentally .The theoretical compression ratio for this concentrating mirror is 330∶1 .The focused spot can be used as a high temperature heat source and the concentrating mirror can be used in a solar heating device .%提出了一种组合非球面反射型太阳能聚光镜并给出了设计方法。聚光镜由38片非球面组成,每一片非球面都由一组特定系数C,a2,a4,a6,a8,a10的偶次非球面方程决定,是此特定非球面的一部分。根据非球面方程和光反射定律矢量形式,导出了非球面内壁上太阳反射光束的方向矢量与非球面系数C,a2,a4,a6,a8,a10的关系,适当地选择这些非球面系数,即适当地调整非球面面型,可以使太阳反射光束具有特定的方向矢量,使入射到非球面内壁上的太阳光束反射后全部聚焦在某一特定的区域

  9. Conjugate metamaterials and the perfect lens

    CERN Document Server

    Xu, Yadong; Xu, Lin; Chen, Huanyang

    2015-01-01

    In this letter, we show how transformation optics makes it possible to design what we call conjugate metamaterials. We show that these materials can also serve as substrates for making a subwavelength-resolution lens. The so-called "perfect lens", which is a lens that could focus all components of light (including propagating and evanescent waves), can be regarded as a limiting case, in which the respective conjugate metamaterials approach the characteristics of left-handed metamaterials, which have a negative refractive index.

  10. PMMA lens with high efficiency and reliability

    Science.gov (United States)

    Matsuzaki, Ichiro; Abe, Koji; Fujita, Katsuhiro

    2013-09-01

    Polymethyl Methacrylate (PMMA) Fresnel lenses are increasingly being used in concentrated photovoltaic (CPV) systems installed outdoors and, accordingly, emphasis is being placed on the durability of such lenses with regard to light transmittance when subject to ultraviolet (UV) light and dust exposure. Accelerated testing methods for evaluating durability under UV exposure were established, allowing development of a lens material with improved UV resistance. Simultaneously, through a proprietary molding method, a Fresnel lens that boasts favorable light concentration efficiency with little deformation even after prolonged outdoor use was developed. Moreover, the lens incorporates a new hard-coat finish that possesses sand durability and UV resistance comparable to that of tempered glass.

  11. High-Efficiency Ultra-Precision Turning for Complex Aspheric Mirrors%复杂非球面镜高效超精密车削加工法

    Institute of Scientific and Technical Information of China (English)

    张效栋; 房丰洲; 程颖; 魏桂爽

    2010-01-01

    This paper introduced the categories of complex aspheric mirrors to study the fabrication of this complex surface using ultra-precision diamond turning.The machining method and cutting path optimal design were proposed in detail.In experiments,one rotationally symmetric complex aspheric mirror was machined.After cutting,each segment of aspheric was measured using the ultra-precision measuring method,with the results used to compensate the cutting to achieve the ultimate surface roughness Ra of5.14 nm and a form error P-V within 200 nm.Besides,another non-rotationally symmetric aspheric array was also machined experimentally with the cutting path designed by the proposed method.The cutting parameters were computed according to the surface form for machining and the finished surface roughness Ra achieved was 7.81 nm.The experimental results prove that the proposed high-efficiency machining method can meet most requirements of complex aspheric.%本文中对复杂面形的非球面镜进行了分类,并从加工方法和加工路径优化设计等方面研究了复杂非球面镜的超精密车削方法.对回转对称的复杂非球面镜进行了加工实验,并借助超精密测量技术对各段曲面进行面形测量,依据测量结果实现面形补偿加工.最终粗糙度Ra达5.14 nm,形状精度P-V值达200 nm.采用提出的方法对非回转对称的非球面阵列进行加工路径设计,根据具体面形进行加工参数选择和实际加工,得到粗糙度R.为7.81nm的表面.实验结果证明了提出的加工方法高效实用,可以满足大部分复杂非球面的应用需求.

  12. 非零位检测凸非球面反射镜的研究%Measurement of convex aspheric mirror by non-null testing

    Institute of Scientific and Technical Information of China (English)

    王孝坤

    2012-01-01

    Conventional testing methods for convex aspheric surfaces were briefly reviewed, and two novel methods for testing convex asphere by partial compensation method and sub-aperture stitching interferometry (SSI) were proposed. The basic principle and theory of the two methods were investigated. The partial compensator was designed and customized, the system error of the partial compensator was calibrated, and the synthetical optimization stitching model and the effective stitching algorithm were established based on homogeneous coordinate transformation and simultaneous least-squares fitting. The prototype and setup for testing of convex asphere by the non-null testing were developed. A convex SiC asphere with the aperture of 130 mm was tested by the two methods respectively. The results show that the difference of PV and RMS error between SSI and partial compensation is 0. 010 λ and 0. 002 λ respectively, the full aperture surface maps of the two methods are consistent and it provides two non-null testing methods for measuring convex aspheric surfaces.%在简要总结各种检测凸非球面方法优缺点的基础上,提出了利用部分补偿法和子孔径拼接干涉检测凸非球面的新方法.分别研究和分析了这两种非零位检测非球面方法的基本原理和基础理论;设计并制作了部分补偿器件,并对其系统误差进行了标定;开发了综合优化和误差均化的子孔径拼接算法;设计并研制了两种方法都适用的检测装置.并结合实例对一口径为130 mm的碳化硅凸非球面分别进行了部分补偿检测和子孔径拼接测量,这两种方法测量所得的全口径面形分布是一致的,其PV值和RMS值的偏差仅为0.010λ和0.002λ(λ=0.632 8μm).从而提供了两种非零位补偿测试凸非球面的手段.

  13. Refractive X-ray lens for high pressure experiments at SPring-8

    CERN Document Server

    Ohishi, Y; Ishii, M; Ishikawa, T; Shimomura, O

    2001-01-01

    A stacked compound refractive X-ray lens was designed to produce an efficiently focused (phi (cursive,open) Greek<0.1 mm) beam for high-pressure experiments at SPring-8. High-pressure X-ray diffraction requires an intense, high-energy and monochromatic X-ray beam in order to penetrate the absorptive window of a diamond anvil cell (DAC). Our lens, producing a focal spot of 120x275 mu m sup 2 and a peak gain of 12, is well matched to these requirements. It is composed of many plastic chips made by molding, which allows many identical chips to be made precisely. Other advantages of this lens include high throughput, simple energy tunability and easy installation.

  14. Study on the influence of the rotational speed of polishing disk on material removal in aspheric surface compliant polishing

    Directory of Open Access Journals (Sweden)

    Liyong Hu

    2015-03-01

    Full Text Available When a soft polishing tool is compressed on a stiff workpiece of curved surface, the contact area is a piece of the curved surface. In the process of aspheric surface polishing, the machining speed is always provided by the rotational speed of the spindle of a computer numerical control lathe. Yet, the polishing tool is usually made rotating to remove cutting scraps and broken abrasives from the contact area. The rotational speed of the polishing tool would change the distribution state of the relative speed in the whole contact area, and it would definitely change the volume of material removal in the surface of the workpiece. This article studies how the rotational speed of the polishing tool changes the distribution state of the relative speed in the whole contact area and material removal in the volume of the surface of the workpiece. The computing results show that the volume of material removal increases with the increase in both the rotational speed of polishing disk and the rotational speed of lathe spindle, but the polishing quality is totally not in this case.

  15. Comprehensive Evaluation of Anterior Corneal Change in Asphericity Calculated by the Tangential Radius of Curvature after LASIK

    Science.gov (United States)

    Ying, Jinglu; Cai, Jianqiu; Zhu, Leru

    2017-01-01

    To evaluate the change in the anterior corneal asphericity (ΔQ) comprehensively calculated using the tangential radius (rt) after LASIK. Forty-two right eyes were evaluated using the Orbscan II corneal topographer. The pre- and postoperative Q-values of the flat principal semimeridians calculated by the sagittal radius were compared to those by the tangential radius. The Q-value of each semimeridian in the horizontal region was calculated by rt. Fourier fitting was used to model the 360-semimeridional variation of Q-values and to fit the Q-values in the vertical region before and after surgery. There were significant differences in Q-values between the two methods before (P < 0.001) and after surgery (P = 0.003). A significant increase in postoperative Q-value was detected compared to preoperative Q-value (P < 0.001) calculated by rt. The 360-semimeridional variation of the Q-values was well fitted with a third- and fourth-degree Fourier function before and after surgery. The ΔQ-value distribution presented double valley variation, with the amount of ΔQ being lowest in the near-vertical regions and highest in the near-horizontal regions. Calculating the Q-value with rt combined with Fourier fitting, we evaluated 360 ΔQ-values' variation of semimeridians of the entire anterior corneal surface and then displayed true and complete anterior corneal shape after LASIK.

  16. Bionic intraocular lens with variable focus and integrated structure

    Science.gov (United States)

    Liang, Dan; Wang, Xuan-Yin; Du, Jia-Wei; Xiang, Ke

    2015-10-01

    This paper proposes a bionic accommodating intraocular lens (IOL) for ophthalmic surgery. The designed lens has a solid-liquid mixed integrated structure, which mainly consists of a support ring, elastic membrane, rigid lens, and optical liquid. The lens focus can be adjusted through the deformation of the lens front surface when compressed. The integrated structure of the IOL is presented, as well as a detailed description of the lens materials and fabrication process. Images under different radial pressures are captured, and the lens deformation process, accommodating range, density, and optical property are analyzed. The designed lens achieves a 14.6 D accommodating range under a radial pressure of 51.4 mN and a 0.24 mm alteration of the lens outer radius. The deformation property of the lens matches well with the characteristic of the eye and shows the potential to help patients fully recover their vision accommodation ability after the cataract surgery.

  17. Restoring lens capsule integrity enhances lens regeneration in New Zealand albino rabbits and cats.

    Science.gov (United States)

    Gwon, A; Gruber, L J; Mantras, C

    1993-11-01

    In studies conducted by numerous investigators for 150 years, lenses regenerated following endocapsular lens extraction in New Zealand albino rabbits have been irregular in shape, appearing primarily doughnut-shaped as a result of lack of lens growth at the site of the anterior capsulotomy and its adhesion to the posterior capsule. In the present study, we restored the lens capsule integrity by inserting a collagen patch at the time of surgery to seal the anterior capsulotomy and to improve the shape and structure of the regenerated lenses. We then filled the capsule bag with air to prevent adhesions between the anterior and posterior capsule and maintain capsule tautness and shape. Lens regeneration was first noted as early as one to two weeks. Regenerated lens filled approximately 50% of the capsule bag at two weeks and 100% by five weeks. Subsequent growth was in the anterior-posterior direction and measured by A-scan biometry. Lens thickness increased by 0.3 mm per month. The regenerated lenses were spherical with normal cortical structure and a nuclear opacity. In conclusion, restoration of lens capsular integrity with a collagen patch following endocapsular lens extraction enhanced the shape, structure, and growth rate of the regenerated lenses. In addition, lens regeneration was shown to occur in two cats.

  18. Ensuring Safe Use of Contact Lens Solution

    Science.gov (United States)

    ... evaluating contact lens solutions and the development of Acanthamoeba keratitis, a rare but serious eye infection that's ... contact lenses to water has been associated with Acanthamoeba keratitis, a corneal infection that is resistant to ...

  19. Variable-focus cylindrical liquid lens array

    Science.gov (United States)

    Zhao, Wu-xiang; Liang, Dong; Zhang, Jie; Liu, Chao; Zang, Shang-fei; Wang, Qiong-hua

    2013-06-01

    A variable-focus cylindrical liquid lens array based on two transparent liquids of different refractive index is demonstrated. An elastic membrane divides a transparent reservoir into two chambers. The two chambers are filled with liquid 1 and liquid 2, respectively, which are of different refractive index. The micro-clapboards help liquid 1, liquid 2 and the elastic membrane form a cylindrical lens array. Driving these two liquids to flow can change the shape of the elastic membrane as well as the focal length. In this design, the gravity effect of liquid can be overcome. A demo lens array of positive optical power is developed and tested. Moreover, a potential application of the proposed lens array for autostereoscopic 3D displays is emphasized.

  20. Role of Aquaporin 0 in lens biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Sindhu Kumari, S.; Gupta, Neha [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Shiels, Alan [Washington University School of Medicine, St. Louis, MO (United States); FitzGerald, Paul G. [Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA (United States); Menon, Anil G. [University of Cincinnati College of Medicine, Cincinnati, OH (United States); Mathias, Richard T. [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States)

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and

  1. Role of Aquaporin 0 in lens biomechanics.

    Science.gov (United States)

    Sindhu Kumari, S; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G; Menon, Anil G; Mathias, Richard T; Varadaraj, Kulandaiappan

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5(-/-)), AQP0 KO (heterozygous KO: AQP0(+/-); homozygous KO: AQP0(-/-); all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0(+/-) lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to confer

  2. Veselago lens by photonic hyper-crystals

    CERN Document Server

    Huang, Zun

    2014-01-01

    An imaging system functioning as a Veselago lens has been proposed based on the novel concept of photonic "hyper-crystal" -- an artificial optical medium synthesizing the properties of hyperbolic materials and photonic crystals. This Veselago lens shows a nearly constant negative refractive index and substantially reduced image aberrations. It can find potential applications in photolithography and hot-spots detection of silicon-based integrated circuits.

  3. Evolution and the Calcite Eye Lens

    CERN Document Server

    Williams, Vernon L

    2013-01-01

    Calcite is a uniaxial, birefringent crystal, which in its optically transparent form, has been used for animal eye lenses, the trilobite being one such animal. Because of the calcite birefringence there is a difficulty in using calcite as a lens. When the propagation direction of incoming light is not exactly on the c-axis, the mages blur. In this paper, calcite blurring is evaluated, and the non-blurring by a crystallin eye lens is compared to a calcite one.

  4. Environmental standards for intraocular lens implantation.

    Science.gov (United States)

    Crawford, B A; Kaufman, D V

    1984-02-01

    Successful implantation of prosthetic devices depends upon their freedom from postoperative inflammation and infection. Techniques and lessons learned in orthopaedic and other implant surgery should be applied to intraocular lens implantation. The avoidance of contamination by particles and micro-organisms is one essential principle of the surgical procedure. Practical steps are described to reduce both types of contamination. These measures taken together are recommended for adoption as a standard of environmental safety for lens implantation.

  5. Bilateral Pseudoexfoliation Deposits on Intraocular Lens Implants

    OpenAIRE

    Elena Bonafonte Marquez; Sergio Bonafonte Royo

    2015-01-01

    We present a rare case of bilateral pseudoexfoliative deposits on both intraocular lens (IOL) implants in an 83-year-old woman with no other associated pathology, 5 years after cataract surgery. Pseudoexfoliation syndrome is the most common cause of secondary open-angle glaucoma worldwide and these deposits are usually found on the natural lens. The fact that pseudoexfoliative deposits have been found on IOL implants implies the need for a thorough examination in pseudophakic patients, for i...

  6. Introduction to the development of intraocular lens

    Science.gov (United States)

    Li, Yifan; Peng, Runling; Hu, Shuilan; Wei, Maowei; Chen, Jiabi

    2013-08-01

    In order to cure the cataract disease or injuries in eyes, intraocular lens(IOL) has been studied all the time to replace the crystalline lens in human eyes. Researches on IOL are started early from 19th century, and it develops greatly in the hundreds years after. This article introduces several main kinds of IOLs that appear in the development history of IOL, and raises the double-liquid zoom IOL based on electrowetting, which will be the trend of IOL study.

  7. A Spectrometer Based on Diffractive Lens

    Institute of Scientific and Technical Information of China (English)

    WANG Daoyi; YAN Yingbai; JIN Guofan; WU Minxian

    2001-01-01

    A novel spectrometer is designed based on diffractive lens. It is essentially a flat field spectrometer. All the focal points are along the optical axis. Besides, all the asymmetrical aberrations vanish in our mounting. Thus low aberration can be obtained. In this article a diffractive lens is modeled as a special grating and analyzed by using a grating-based method. And a stigmatic point is introduced to reduce the aberrations.

  8. In vivo human crystalline lens topography

    OpenAIRE

    Ortiz, Sergio; Pérez Merino, Pablo; Gambra, Enrique; Castro, Alberto; Marcos, Susana

    2012-01-01

    Custom high-resolution high-speed anterior segment spectral domain optical coherence tomography (OCT) was used to characterize three-dimensionally (3-D) the human crystalline lens in vivo. The system was provided with custom algorithms for denoising and segmentation of the images, as well as for fan (scanning) and optical (refraction) distortion correction, to provide fully quantitative images of the anterior and posterior crystalline lens surfaces. The method was tested on an artificial eye ...

  9. James Webb Space Telescope Optical Simulation Testbed II. Design of a Three-Lens Anastigmat Telescope Simulator

    CERN Document Server

    Choquet, Élodie; N'Diaye, Mamadou; Perrin, Marshall D; Soummer, Rémi

    2014-01-01

    The James Webb Space Telescope (JWST) Optical Simulation Testbed (JOST) is a tabletop experiment designed to reproduce the main aspects of wavefront sensing and control (WFSC) for JWST. To replicate the key optical physics of JWST's three-mirror anastigmat (TMA) design at optical wavelengths we have developed a three-lens anastigmat optical system. This design uses custom lenses (plano-convex, plano-concave, and bi-convex) with fourth-order aspheric terms on powered surfaces to deliver the equivalent image quality and sampling of JWST NIRCam at the WFSC wavelength (633~nm, versus JWST's 2.12~micron). For active control, in addition to the segmented primary mirror simulator, JOST reproduces the secondary mirror alignment modes with five degrees of freedom. We present the testbed requirements and its optical and optomechanical design. We study the linearity of the main aberration modes (focus, astigmatism, coma) both as a function of field point and level of misalignments of the secondary mirror. We find that t...

  10. Large-scale fabrication of micro-lens array by novel end-fly-cutting-servo diamond machining.

    Science.gov (United States)

    Zhu, Zhiwei; To, Suet; Zhang, Shaojian

    2015-08-10

    Fast/slow tool servo (FTS/STS) diamond turning is a very promising technique for the generation of micro-lens array (MLA). However, it is still a challenge to process MLA in large scale due to certain inherent limitations of this technique. In the present study, a novel ultra-precision diamond cutting method, as the end-fly-cutting-servo (EFCS) system, is adopted and investigated for large-scale generation of MLA. After a detailed discussion of the characteristic advantages for processing MLA, the optimal toolpath generation strategy for the EFCS is developed with consideration of the geometry and installation pose of the diamond tool. A typical aspheric MLA over a large area is experimentally fabricated, and the resulting form accuracy, surface micro-topography and machining efficiency are critically investigated. The result indicates that the MLA with homogeneous quality over the whole area is obtained. Besides, high machining efficiency, extremely small volume of control points for the toolpath, and optimal usage of system dynamics of the machine tool during the whole cutting can be simultaneously achieved.

  11. Photon nanojet lens: design, fabrication and characterization

    Science.gov (United States)

    Xu, Chen; Zhang, Sichao; Shao, Jinhai; Lu, Bing-Rui; Mehfuz, Reyad; Drakeley, Stacey; Huang, Fumin; Chen, Yifang

    2016-04-01

    In this paper, a novel nanolens with super resolution, based on the photon nanojet effect through dielectric nanostructures in visible wavelengths, is proposed. The nanolens is made from plastic SU-8, consisting of parallel semi-cylinders in an array. This paper focuses on the lens designed by numerical simulation with the finite-difference time domain method and nanofabrication of the lens by grayscale electron beam lithography combined with a casting/bonding/lift-off transfer process. Monte Carlo simulation for injected charge distribution and development modeling was applied to define the resultant 3D profile in PMMA as the template for the lens shape. After the casting/bonding/lift-off process, the fabricated nanolens in SU-8 has the desired lens shape, very close to that of PMMA, indicating that the pattern transfer process developed in this work can be reliably applied not only for the fabrication of the lens but also for other 3D nanopatterns in general. The light distribution through the lens near its surface was initially characterized by a scanning near-field optical microscope, showing a well defined focusing image of designed grating lines. Such focusing function supports the great prospects of developing a novel nanolithography based on the photon nanojet effect.

  12. Lens Biology is a Dimension of Neurobiology.

    Science.gov (United States)

    Frederikse, Peter; Kasinathan, Chinnaswamy

    2017-02-04

    There is a second cell type in your body that expresses scores of the most intensively studied genes in neuroscience and exclusively shares critical interdependent modes of molecular regulation that include a network first described as responsible for the basic bifurcation of neuronal from non-neuronal gene expression in vertebrates. Neurons and lens cells are among the most ancient animal cell types, yet neurons have an exclusive status also attributed to roles underlying sensation, movement, and cognition. However, this status is challenged by cells in the lens of the eye. The extent and detail of internally consistent parallels with neuron biology now catalogued in their second native cell type in the lens provide a detailed model of interdependent neuron gene expression in lens development and non-neuronal role in vision. These comprehensive parallels identify the lens as a dimension of neurobiology and a fundamental new perspective on neurodevelopment and its disorders. Finally, this understanding identifies that hallmark neuronal gene expression and key modes of associated molecular regulation evolved in tandem in the lens.

  13. Advanced gradient-index lens design tools to maximize system performance and reduce SWaP

    Science.gov (United States)

    Campbell, Sawyer D.; Nagar, Jogender; Brocker, Donovan E.; Easum, John A.; Turpin, Jeremiah P.; Werner, Douglas H.

    2016-05-01

    GRadient-INdex (GRIN) lenses have long been of interest due to their potential for providing levels of performance unachievable with traditional homogeneous lenses. While historically limited by a lack of suitable materials, rapid advancements in manufacturing techniques, including 3D printing, have recently kindled a renewed interest in GRIN optics. Further increasing the desire for GRIN devices has been the advent of Transformation Optics (TO), which provides the mathematical framework for representing the behavior of electromagnetic radiation in a given geometry by "transforming" it to an alternative, usually more desirable, geometry through an appropriate mapping of the constituent material parameters. Using TO, aspherical lenses can be transformed to simpler spherical and flat geometries or even rotationally-asymmetric shapes which result in true 3D GRIN profiles. Meanwhile, there is a critical lack of suitable design tools which can effectively evaluate the optical wave propagation through 3D GRIN profiles produced by TO. Current modeling software packages for optical lens systems also lack advanced multi-objective global optimization capability which allows the user to explicitly view the trade-offs between all design objectives such as focus quality, FOV, ▵nand focal drift due to chromatic aberrations. When coupled with advanced design methodologies such as TO, wavefront matching (WFM), and analytical achromatic GRIN theory, these tools provide a powerful framework for maximizing SWaP (Size, Weight and Power) reduction in GRIN-enabled optical systems. We provide an overview of our advanced GRIN design tools and examples which minimize the presence of mono- and polychromatic aberrations in the context of reducing SWaP.

  14. Clinical Outcomes after Uncomplicated Cataract Surgery with Implantation of the Tecnis Toric Intraocular Lens

    Science.gov (United States)

    Lubiński, Wojciech; Kaźmierczak, Beata; Gronkowska-Serafin, Jolanta; Podborączyńska-Jodko, Karolina

    2016-01-01

    Purpose. To evaluate the clinical outcomes after uncomplicated cataract surgery with implantation of an aspheric toric intraocular lens (IOL) during a 6-month follow-up. Methods. Prospective study including 27 consecutive eyes of 18 patients (mean age: 66.1 ± 11.4 years) with a visually significant cataract and corneal astigmatism ≥ 0.75 D and undergoing uncomplicated cataract surgery with implantation of the Tecnis ZCT toric IOL (Abbott Medical Optics). Visual, refractive, and keratometric outcomes as well as IOL rotation were evaluated during a 6-month follow-up. At the end of the follow-up, patient satisfaction and perception of optical/visual disturbances were also evaluated using a subjective questionnaire. Results. At 6 months after surgery, mean LogMAR uncorrected (UDVA) and corrected distance visual acuity (CDVA) were 0.19 ± 0.12 and 0.14 ± 0.10, respectively. Postoperative UDVA of 20/40 or better was achieved in 92.6% of eyes. Mean refractive cylinder decreased significantly from −3.73 ± 1.96 to −1.42 ± 0.88 D (p < 0.001), while keratometric cylinder did not change significantly (p = 0.44). Mean absolute IOL rotation was 1.1 ± 2.4°, with values of more than 5° in only 2 eyes (6.9%). Mean patient satisfaction score was 9.70 ± 0.46, using a scale from 0 (not at all satisfied) to 10 (very satisfied). No postoperative optical/visual disturbances were reported. Conclusion. Cataract surgery with implantation of the Tecnis toric IOL is an effective method of refractive correction in eyes with corneal astigmatism due to the good IOL positional stability, providing high levels of patient's satisfaction. PMID:27022478

  15. Development of a Fresnel lens for cold neutrons based on neutron refractive optics

    CERN Document Server

    Oku, T; Moriyasu, S; Yamagata, Y; Ohmori, H; Takizawa, Y; Shimizu, H M; Hirota, T; Kiyanagi, Y; Ino, T; Furusaka, M; Suzuki, J

    2001-01-01

    We have developed compound refractive lenses (CRLs) for cold neutrons, which are made of vitreous silica and have an effective potential of (90.1-2.7x10 sup - sup 4 i) neV. In the case of compound refractive optics, neutron absorption by the material deteriorates lens performance. Thus, to prevent an increase in neutron absorption with increasing beam size, we have developed Fresnel lenses using the electrolytic in-process dressing grinding technique. The lens characteristics were carefully investigated with experimental and numerical simulation studies. The lenses functioned as a neutron focusing lens, and the focal length of 14 m was obtained with a 44-element series of the Fresnel lenses for 10 A neutrons. Moreover, good neutron transmission of 0.65 for 15 A neutrons was obtained due to the shape effect. According to comprehensive analysis of the obtained results, it is possible to realize a CRL for practical use by choosing a suitable lens shape and material.

  16. DISSECTING THE GRAVITATIONAL LENS B1608+656. I. LENS POTENTIAL RECONSTRUCTION

    NARCIS (Netherlands)

    Suyu, S. H.; Marshall, P. J.; Blandford, R. D.; Fassnacht, C. D.; Koopmans, L. V. E.; McKean, J. P.; Treu, T.

    2009-01-01

    Strong gravitational lensing is a powerful technique for probing galaxy mass distributions and for measuring cosmological parameters. Lens systems with extended source-intensity distributions are particularly useful for this purpose since they provide additional constraints on the lens potential ( m

  17. Gravitational binary-lens events with prominent effects of lens orbital motion

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.; Han, C.; Choi, J.-Y. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Udalski, A.; Szymański, M. K.; Kubiak, M.; Soszyński, I.; Pietrzyński, G.; Poleski, R.; Ulaczyk, K.; Pietrukowicz, P.; Kozłowski, S.; Skowron, J.; Wyrzykowski, Ł. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Gould, A.; Gaudi, B. S. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Beaulieu, J.-P. [Institut d' Astrophysique de Paris, UMR 7095 CNRS-Université Pierre and Marie Curie, 98bis Bd Arago, F-75014 Paris (France); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Depoy, D. L. [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Dong, Subo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Collaboration: OGLE Collaboration; μFUN Collaboration; PLANET Collaboration; RoboNet Collaboration; and others

    2013-12-01

    Gravitational microlensing events produced by lenses composed of binary masses are important because they provide a major channel for determining physical parameters of lenses. In this work, we analyze the light curves of two binary-lens events, OGLE-2006-BLG-277 and OGLE-2012-BLG-0031, for which the light curves exhibit strong deviations from standard models. From modeling considering various second-order effects, we find that the deviations are mostly explained by the effect of the lens orbital motion. We also find that lens parallax effects can mimic orbital effects to some extent. This implies that modeling light curves of binary-lens events not considering orbital effects can result in lens parallaxes that are substantially different from actual values and thus wrong determinations of physical lens parameters. This demonstrates the importance of routine consideration of orbital effects in interpreting light curves of binary-lens events. It is found that the lens of OGLE-2006-BLG-277 is a binary composed of a low-mass star and a brown dwarf companion.

  18. Effect of infusion bottle height on lens power after lens refilling with and without a plug

    NARCIS (Netherlands)

    Koopmans, SA; Terwee, T; Haitjema, HJ; Kooijman, AC; Barkhof, J

    2003-01-01

    Purpose: To evaluate the influence of intraoperative infusion bottle height on the power of refilled pig lenses. Setting: Research Laboratory, Pharmacia Intraocular Lens Manufacturing Plant, Groningen, The Netherlands. Methods: This study comprised 2 groups of pig eyes. In 1 group, the lens was refi

  19. The Sloan Lens ACS Survey. V. The full ACS strong-lens sample

    NARCIS (Netherlands)

    Bolton, Adam S.; Burles, Scott; Koopmans, Leon V. E.; Treu, Tommaso; Gavazzi, Raphael; Moustakas, Leonidas A.; Wayth, Randall; Schlegel, David J.

    2008-01-01

    We present the definitive data for the full sample of 131 strong gravitational lens candidates observed with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope by the Sloan Lens ACS (SLACS) Survey. All targets were selected for higher redshift emission lines and lower redshift c

  20. Evaluation of actual retinal images produced by misaligned aspheric intraocular lenses in a model eye

    Directory of Open Access Journals (Sweden)

    Fujikado T

    2014-11-01

    Full Text Available Takashi Fujikado,1 Makoto Saika2 1Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan; 2Research and Development Department of Topcon Corporation, Tokyo, Japan Purpose: To examine the effect of misalignment (decentration and tilt of intraocular lenses (IOLs on retinal image quality using a water-immersed model eye with corneal spherical aberration adjusted to the values found in normal human eyes (spherical aberration 0.25 µm; pupil diameter 6 mm.Methods: Three types of IOL holders were prepared. The first was without decentration or tilt, the second had a decentration of 0.5 mm, and the third had a tilt of 5.0°. One spherical IOL and three aspherical IOLs, each with a power of +20 D, were set in the holders and their optical properties (wave front aberration, defocused modulation transfer function, defocused point spread function, and Landolt ring simulations were compared.Results: Coma aberrations generated by misaligned IOLs were related to the spherical aberration corrective power of the IOLs. Landolt ring simulations show that the depth of focus increased as spherical aberration increased and that the retinal image quality was degraded by increases in coma aberration.Conclusion: Coma aberration was generated by IOLs with a large degree of spherical aberration correction, leading to reduced retinal image quality when the IOL was misaligned. This suggests that, in a clinical setting, the quality of vision might be improved by reducing the degree of coma aberration using IOLs that retain, or minimally correct, spherical aberration. Keywords: coma aberration, decentration, misalignment, spherical aberration, tilt

  1. Two Distinct-absorption X-Ray Components from Type IIn Supernovae: Evidence for Asphericity in the Circumstellar Medium

    Science.gov (United States)

    Katsuda, Satoru; Maeda, Keiichi; Bamba, Aya; Terada, Yukikatsu; Fukazawa, Yasushi; Kawabata, Koji; Ohno, Masanori; Sugawara, Yasuharu; Tsuboi, Yohko; Immler, Stefan

    2016-12-01

    We present multi-epoch X-ray spectral observations of three Type IIn supernovae (SNe), SN 2005kd, SN 2006jd, and SN 2010jl, acquired with Chandra, XMM-Newton, Suzaku, and Swift. Previous extensive X-ray studies of SN 2010jl have revealed that X-ray spectra are dominated by thermal emission, which likely arises from a hot plasma heated by a forward shock propagating into a massive circumstellar medium (CSM). Interestingly, an additional soft X-ray component was required to reproduce the spectra at a period of ˜1-2 years after the SN explosion. Although this component is likely associated with the SN, its origin remained an open question. We find a similar, additional soft X-ray component from the other two SNe IIn as well. Given this finding, we present a new interpretation for the origin of this component; it is thermal emission from a forward shock essentially identical to the hard X-ray component, but directly reaches us from a void of the dense CSM. Namely, the hard and soft components are responsible for the heavily and moderately absorbed components, respectively. The co-existence of the two components with distinct absorptions as well as the delayed emergence of the moderately absorbed X-ray component could be evidence for asphericity of the CSM. We show that the X-ray spectral evolution can be qualitatively explained by considering a torus-like geometry for the dense CSM. Based on our X-ray spectral analyses, we estimate the radius of the torus-like CSM to be on the order of ˜5 × 1016 cm.

  2. Design and high-volume manufacture of low-cost molded IR aspheres for personal thermal imaging devices

    Science.gov (United States)

    Zelazny, A. L.; Walsh, K. F.; Deegan, J. P.; Bundschuh, B.; Patton, E. K.

    2015-05-01

    The demand for infrared optical elements, particularly those made of chalcogenide materials, is rapidly increasing as thermal imaging becomes affordable to the consumer. The use of these materials in conjunction with established lens manufacturing techniques presents unique challenges relative to the cost sensitive nature of this new market. We explore the process from design to manufacture, and discuss the technical challenges involved. Additionally, facets of the development process including manufacturing logistics, packaging, supply chain management, and qualification are discussed.

  3. [Representation and mathematical analysis of human crystalline lens].

    Science.gov (United States)

    Tălu, Stefan; Giovanzana, Stefano; Tălu, Mihai

    2011-01-01

    The surface of human crystalline lens can be described and analyzed using mathematical models based on parametric representations, used in biomechanical studies and 3D solid modeling of the lens. The mathematical models used in lens biomechanics allow the study and the behavior of crystalline lens on variables and complex dynamic loads. Also, the lens biomechanics has the potential to improve the results in the development of intraocular lenses and cataract surgery. The paper presents the most representative mathematical models currently used for the modeling of human crystalline lens, both optically and biomechanically.

  4. Imaging characteristics of a volume holographic lens

    Science.gov (United States)

    Yang, Jing; Jiang, Zhu-qing; Xu, Zhi-qiang; Liu, Shao-jie; Sun, Ya-jun; Tao, Shi-quan

    2009-07-01

    A volume holographic grating lens can reconstruct the three-dimensional information by conducting multiple optical slicing of an object based on Bragg selectivity of the volume holographic grating. In this paper, we employ the point-spread function of volume holographic imaging system to theoretically analyze its imaging resolution. In the experiments, the volume holographic gratings are made with a spherical reference (SR) and a planar reference (PR), respectively, and used as volume holographic imaging lens in our imaging system. The longitudinal and lateral defocusing characteristics of volume holographic lens with SR and with PR are investigated experimentally by displacing the interested objects from original reference location, respectively. The effects of the parameters of the volume holographic lens on the longitudinal and lateral resolution are also discussed. The experimental results show that increasing the size of the volume holographic lens can improve the depth resolution, and in particular, it has greater influence on SR VHI. The lateral selectivity of SR VHI is more sensitive than that of PR VHI, and the Bragg degenerate diffraction of PR VHI on the y axis is obviously observed.

  5. Apoptosis in the lens anlage of the heritable lens aplastic mouse (lap mouse).

    Science.gov (United States)

    Aso, S; Tashiro, M; Baba, R; Sawaki, M; Noda, S; Fujita, M

    1998-08-01

    Adult homozygous lap mice show various eye abnormalities, such as aphakia, retinal disorganization, and dysplasia of the cornea and anterior chamber. In the fetal eye of a homozygous lap mouse, the lens placode seems to develop normally. However, the lens vesicle progresses abnormally to form a mass of cells without a cavity, and the mass vanishes soon afterward. We examined cell death in the lens anlage of this mutant. The lens anlagen of homozygous lap and normal mice from days 10 to 12 of gestation were observed by light microscopy after DNA end-labeling by immunohistochemistry and by transmission electron microscopy. By light microscopy, a slight frequency of cell death was detected in the lens anlage encircling the surface ectoderm and in the anlage or in the anlage of both homozygous lap mice and normal mice at day 10 of gestation. Cell death was seen in the lens anlage encircling the surface ectoderm in the normal mouse and sporadically in the anlage of the homozygous lap mouse at day 10.5 of gestation. Cell death was visible at the area of the lens vesicle attached to the surface ectoderm and encircling the surrounding surface ectoderm in the normal mouse, and in the lens anlage encircling the surface ectoderm and the apex areas of the lens anlage in the homozygous lap mouse at day 11 of gestation. At day 12 of gestation, almost no cell death was observed in the lens anlage of the normal mouse. However, extensive areas of cell death were still seen in the lens anlage at its apex, at the inner region, and encircling the surface ectoderm in the homozygous lap mouse. Electron microscopic observation showed that the dead cells observed in the lens anlagen by light microscopy in normal and lap mice are the result of apoptosis. In lap mice, cells with cytoplasmic condensation were observed mainly at days 10 and 10.5 of gestation. Many apoptotic bodies which had been phagocytosed by adjacent cells were seen predominantly at day 11 of gestation. At day 12 of

  6. An inverse and analytic lens design method

    CERN Document Server

    Lu, Yang

    2016-01-01

    Traditional lens design is a numerical and forward process based on ray tracing and aberration theory. This method has limitations because the initial configuration of the lens has to be specified and the aberrations of the lenses have to considered. This paper is an initial attempt to investigate an analytic and inverse lens design method, called Lagrange, to overcome these barriers. Lagrange method tries to build differential equations in terms of the system parameters and the system input and output (object and image). The generalized Snell's law in three dimensional space and the normal of a surface in fundamental differential geometry are applied. Based on the Lagrange method equations for a single surface system are derived which can perfectly image a point object.

  7. The Frontier Fields Lens Modeling Comparison Project

    CERN Document Server

    Meneghetti, M; Coe, D; Contini, E; De Lucia, G; Giocoli, C; Acebron, A; Borgani, S; Bradac, M; Diego, J M; Hoag, A; Ishigaki, M; Johnson, T L; Jullo, E; Kawamata, R; Lam, D; Limousin, M; Liesenborgs, J; Oguri, M; Sebesta, K; Sharon, K; Williams, L L R; Zitrin, A

    2016-01-01

    Gravitational lensing by clusters of galaxies offers a powerful probe of their structure and mass distribution. Deriving a lens magnification map for a galaxy cluster is a classic inversion problem and many methods have been developed over the past two decades to solve it. Several research groups have developed techniques independently to map the predominantly dark matter distribution in cluster lenses. While these methods have all provided remarkably high precision mass maps, particularly with exquisite imaging data from the Hubble Space Telescope (HST), the reconstructions themselves have never been directly compared. In this paper, we report the results of comparing various independent lens modeling techniques employed by individual research groups in the community. Here we present for the first time a detailed and robust comparison of methodologies for fidelity, accuracy and precision. For this collaborative exercise, the lens modeling community was provided simulated cluster images -- of two clusters Are...

  8. Catadioptric aberration correction in cathode lens microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tromp, R.M. [IBM T.J. Watson Research Center, PO Box 218, Yorktown Heights, NY 10598 (United States); Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

    2015-04-15

    In this paper I briefly review the use of electrostatic electron mirrors to correct the aberrations of the cathode lens objective lens in low energy electron microscope (LEEM) and photo electron emission microscope (PEEM) instruments. These catadioptric systems, combining electrostatic lens elements with a reflecting mirror, offer a compact solution, allowing simultaneous and independent correction of both spherical and chromatic aberrations. A comparison with catadioptric systems in light optics informs our understanding of the working principles behind aberration correction with electron mirrors, and may point the way to further improvements in the latter. With additional developments in detector technology, 1 nm spatial resolution in LEEM appears to be within reach. - Highlights: • The use of electron mirrors for aberration correction in LEEM/PEEM is reviewed. • A comparison is made with similar systems in light optics. • Conditions for 1 nm spatial resolution are discussed.

  9. Image watermarking against lens flare effects

    Science.gov (United States)

    Chotikawanid, Piyanart; Amornraksa, Thumrongrat

    2017-02-01

    Lens flare effects in various photo and camera software nowadays can partially or fully damage the watermark information within the watermarked image. We propose in this paper a spatial domain based image watermarking against lens flare effects. The watermark embedding is based on the modification of the saturation color component in HSV color space of a host image. For watermark extraction, a homomorphic filter is used to predict the original embedding component from the watermarked component, and the watermark is blindly recovered by differentiating both components. The watermarked image's quality is evaluated by wPSNR, while the extracted watermark's accuracy is evaluated by NC. The experimental results against various types of lens flare effects from both computer software and mobile application showed that our proposed method outperformed the previous methods.

  10. Louvre-Lens : le Louvre autrement

    OpenAIRE

    Audrey Bodéré

    2010-01-01

    ∙ Quels sont les enjeux du projet Louvre-Lens pour le Musée du Louvre ? Par ce projet, le Louvre participe tant à la politique de décentralisation qu’à une volonté de démocratisation culturelle, en allant à la rencontre de nouveaux publics. Mais le projet scientifique et culturel du Louvre-Lens (PSC) précise aussi que l'un des principaux défis est d'oser le « Louvre autrement ». La présentation des collections est donc repensée pour traduire le monde Louvre à Lens. Le lien entre le Louvre Par...

  11. Louvre-Lens : le Louvre autrement

    Directory of Open Access Journals (Sweden)

    Audrey Bodéré

    2010-04-01

    Full Text Available ∙ Quels sont les enjeux du projet Louvre-Lens pour le Musée du Louvre ? Par ce projet, le Louvre participe tant à la politique de décentralisation qu’à une volonté de démocratisation culturelle, en allant à la rencontre de nouveaux publics. Mais le projet scientifique et culturel du Louvre-Lens (PSC précise aussi que l'un des principaux défis est d'oser le « Louvre autrement ». La présentation des collections est donc repensée pour traduire le monde Louvre à Lens. Le lien entre le Louvre Par...

  12. 3D printed helical antenna with lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2016-12-19

    The gain of an antenna can be enhanced through the integration of a lens, however this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, with a unique combination of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a Fresnel lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a Fresnel lens enhances the gain of a 2-turn helix by around 4.6 dB giving a peak gain of about 12.9 dBi at 8.8 GHz.

  13. Intraocular Lens Calcification; a Clinicopathologic Report

    Directory of Open Access Journals (Sweden)

    Mozhgan Rezaei-Kanavi

    2009-04-01

    Full Text Available

    PURPOSE: To describe the clinical and pathological features of a case of hydrogel intraocular lens (IOL calcification. CASE REPORT: A 48-year-old man underwent explantation of a single-piece hydrophilic acrylic intraocular lens in his left eye because of decreased visual acuity and milky white opalescence of the IOL. The opacified lens was exchanged uneventfully with a hydrophobic acrylic IOL. Gross examination of the explanted IOL disclosed opacification of the optic and haptics. Full-thickness sections of the lens optic were stained with hematoxylin and eosin (H&E, von Kossa and Gram Tworts'. Microscopic examination of the sections revealed fine and diffuse basophilic granular deposits of variable size within the lens optic parallel to the lens curvature but separated from the surface by a moderately clear zone. The deposits were of high calcium content as evident by dark brown staining with von Kossa. Gram Tworts' staining disclosed no microorganisms. CONCLUSION: This report further contributes to the existing literature on hydrogel IOL calcification.

  14. Analytic Models of Plausible Gravitational Lens Potentials

    Energy Technology Data Exchange (ETDEWEB)

    Baltz, Edward A.; Marshall, Phil; Oguri, Masamune

    2007-05-04

    Gravitational lenses on galaxy scales are plausibly modeled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sersic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasizing that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential.We also provide analytic formulae for the lens potentials of Sersic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modeled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses.

  15. Bilateral Pseudoexfoliation Deposits on Intraocular Lens Implants

    Directory of Open Access Journals (Sweden)

    Elena Bonafonte Marquez

    2015-01-01

    Full Text Available We present a rare case of bilateral pseudoexfoliative deposits on both intraocular lens (IOL implants in an 83-year-old woman with no other associated pathology, 5 years after cataract surgery. Pseudoexfoliation syndrome is the most common cause of secondary open-angle glaucoma worldwide and these deposits are usually found on the natural lens. The fact that pseudoexfoliative deposits have been found on IOL implants implies the need for a thorough examination in pseudophakic patients, for it could be the only sign of secondary glaucoma.

  16. Fundamentals of concentric lens systems synthesis

    Science.gov (United States)

    Ezhova, Kseniia; Zverev, Victor; Tochilina, Tatiana; Tymoshchuk, Irina

    2016-09-01

    Introduction of coefficients defining the relationship of the radii of curvature of the surfaces of concentric optical systems, allowed the transformation of the obtained analytical relations in a system of two equations with two unknowns. It is shown that the existence of the solution of the system of equations determined by the optical constants of the selected lens material. The results of the analysis of the conditions of the chromatic aberration correction position and the sequence of obtaining of the system equations define the theoretical basis of the engineering method of parametric synthesis of concentric lens systems. Application of the developed method is illustrated by examples of calculation particular systems design build.

  17. Time resolved thermal lens in edible oils

    Science.gov (United States)

    Albuquerque, T. A. S.; Pedreira, P. R. B.; Medina, A. N.; Pereira, J. R. D.; Bento, A. C.; Baesso, M. L.

    2003-01-01

    In this work time resolved thermal lens spectrometry is applied to investigate the optical properties of the following edible oils: soya, sunflower, canola, and corn oils. The experiments were performed at room temperature using the mode mismatched thermal lens configuration. The results showed that when the time resolved procedure is adopted the technique can be applied to investigate the photosensitivity of edible oils. Soya oil presented a stronger photochemical reaction as compared to the other investigated samples. This observation may be relevant for future studies evaluating edible oils storage conditions and also may contribute to a better understanding of the physical and chemical properties of this important foodstuff.

  18. Pulse transformer for the AA lithium lens

    CERN Multimedia

    1980-01-01

    The antiprotons emanating from the target were initially focused by a magnetic horn. Later on, a Li-lens was used during operation for the SPS collider, until 1992. A Li-rod (130 mm long, 34 mm in diameter) constituted the secondary of a 1:23 pulse-transformer. The half-sine pulse rose to 1000 kA in 900 microsec. The angular acceptance was 95 mrad. In operation after 1992, for LEAR only, a more modest Li-lens was used (155 mm long, diameter 20 mm, 480 kA, risetime 240 microsec, angular acceptance 75 mrad).

  19. Miniature curved artificial compound eyes.

    Science.gov (United States)

    Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L'Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A; Franceschini, Nicolas

    2013-06-04

    In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories.

  20. Experimental Contact Lens to Prevent Glaucoma-Induced Blindness

    Science.gov (United States)

    ... Home Page An Experimental Contact Lens to Prevent Glaucoma-Induced Blindness By Sharon Reynolds Posted January 23, 2014 An experimental contact lens design releases a glaucoma medicine at a steady rate for up to ...

  1. Phakic Pattern Pseudoexfoliation Material Accumulation on Intraocular Lens Surface

    Directory of Open Access Journals (Sweden)

    Emre Güler

    2014-03-01

    Full Text Available Pseudophakic pseudoexfoliation is the accumulation of pseudoexfoliation material on the intraocular lens. Most of the cases have showed scattered flecks of pseudoexfoliation material on the surface of the intraocular lens. However, the phakic pattern consisting of classic three-zone on the intraocular lens is rarely observed. In this case report, we describe a phakic pattern pseudoexfoliation material on the intraocular lens surface 8 years after cataract extraction. (Turk J Ophthalmol 2014; 44: 156-7

  2. Phakic Pattern Pseudoexfoliation Material Accumulation on Intraocular Lens Surface

    OpenAIRE

    Emre Güler; Aylin Tenlik; Tuba Kara Akyüz

    2014-01-01

    Pseudophakic pseudoexfoliation is the accumulation of pseudoexfoliation material on the intraocular lens. Most of the cases have showed scattered flecks of pseudoexfoliation material on the surface of the intraocular lens. However, the phakic pattern consisting of classic three-zone on the intraocular lens is rarely observed. In this case report, we describe a phakic pattern pseudoexfoliation material on the intraocular lens surface 8 years after cataract extraction. (Turk J Ophthalm...

  3. An Ultrasonic Lens Design Based on Prefractal Structures

    OpenAIRE

    Sergio Castiñeira-Ibáñez; Daniel Tarrazó-Serrano; Constanza Rubio; Pilar Candelas; Antonio Uris

    2016-01-01

    The improvement in focusing capabilities of a set of annular scatterers arranged in a fractal geometry is theoretically quantified in this work by means of the finite element method (FEM). Two different arrangements of rigid rings in water are used in the analysis. Thus, both a Fresnel ultrasonic lens and an arrangement of rigid rings based on Cantor prefractals are analyzed. Results show that the focusing capacity of the modified fractal lens is better than the Fresnel lens. This new lens is...

  4. Lens autofluorescence is not increased at high altitude

    DEFF Research Database (Denmark)

    Kessel, Line; Kofoed, Peter Kristian; Zubieta-Calleja, Gustavo;

    2010-01-01

    PURPOSE: To study the relation between ambient environmental ultraviolet radiation exposure and lens fluorescence. METHODS: Non-invasive lens fluorometry measurements were compared in healthy Bolivian and Danish subjects. Background ultraviolet radiation was 4.5 times higher in Bolivia than...... living at sea level at 55 degrees northern latitude. These results suggest that lens ageing, as assessed by lens autofluorometry, is independent of exposure to ultraviolet radiation....

  5. Matter mixing in aspherical core-collapse supernovae: a search for possible conditions for conveying $^{56}$Ni into high velocity regions

    CERN Document Server

    Ono, Masaomi; Ito, Hirotaka; Lee, Shiu-Hang; Mao, Jirong; Hashimoto, Masa-aki; Tolstov, Alexey

    2013-01-01

    We perform two-dimensional axisymmetric hydrodynamic simulations of matter mixing in aspherical core-collapse supernova explosions of a 16.3 $M_{\\odot}$ star with a compact hydrogen envelope. Observations of SN 1987A have provided evidence that $^{56}$Ni synthesized by explosive nucleosynthesis is mixed into fast moving matter ($\\gtrsim$ 3,500 km s$^{-1}$) in the exploding star. In order to clarify the key conditions for reproducing such high velocity of $^{56}$Ni, we revisit matter mixing in aspherical core-collapse supernova explosions. Explosions are initiated artificially by injecting thermal and kinetic energies around the interface between the iron core and the silicon-rich layer. Perturbations of 5% or 30% amplitude in the radial velocities are introduced at several points in time. We found that no high velocity $^{56}$Ni can be obtained if we consider bipolar explosions with perturbations (5% amplitude) of pre-supernova origins. If large perturbations (30% amplitude) are introduced or exist due to som...

  6. A test of lens opacity as an indicator of preclinical Alzheimer Disease.

    Science.gov (United States)

    Bei, Ling; Shui, Ying-Bo; Bai, Fang; Nelson, Suzanne K; Van Stavern, Gregory P; Beebe, David C

    2015-11-01

    Previous studies reported that characteristic lens opacities were present in Alzheimer Disease (AD) patients postmortem. We therefore determined whether cataract grade or lens opacity is related to the risk of Alzheimer dementia in participants who have biomarkers that predict a high risk of developing the disease. AD biomarker status was determined by positron emission tomography-Pittsburgh compound B (PET-PiB) imaging and cerebrospinal fluid (CSF) levels of Aβ42. Cognitively normal participants with a clinical dementia rating of zero (CDR = 0; N = 40) or with slight evidence of dementia (CDR = 0.5; N = 2) were recruited from longitudinal studies of memory and aging at the Washington University Knight Alzheimer's Disease Research Center. The age, sex, race, cataract type and cataract grade of all participants were recorded and an objective measure of lens light scattering was obtained for each eye using a Scheimpflug camera. Twenty-seven participants had no biomarkers of Alzheimer dementia and were CDR = 0. Fifteen participants had biomarkers indicating increased risk of AD, two of which were CDR = 0.5. Participants who were biomarker positive were older than those who were biomarker negative. Biomarker positive participants had more advanced cataracts and increased cortical light scattering, none of which reached statistical significance after adjustment for age. We conclude that cataract grade or lens opacity is unlikely to provide a non-invasive measure of the risk of developing Alzheimer dementia.

  7. Recent advances in the model of aspherical dust dynamics for GIADA experiment in the coma of 67P/Churyumov-Gerasimenko

    Science.gov (United States)

    Ivanovski, Stavro; Zakharov, Vladimir; Crifo, Jean-Francois; Della Corte, Vincenzo; Fulle, Marco; Rotundi, Alessandra

    2013-04-01

    Introduction. We report the latest improvements of the model of aspherical dust grain dynamics [1] in the cometary atmosphere of 67P/Churyumov- Gerasimenko(67P/C-G). The model is aimed to support the scien- tific objectives of GIADA (Grain Impact Analyzer and Dust Accumulator) in-situ experiment [2] on board of the ESA ROSETTA spacecraft. The instrument will measure individual dust grain mass, number density and velocity in the immediate vicinity of the cometary nucleus. In this report we discuss the distinctions in the dy- namics of the aspherical dust in comparison with the spherical approximation developed in the currently used 3D+t spherical dust models [3,4]. Model. We assume that dust grains are homogeneous, isothermal polygonal convex bodies (close to ellipsoid of revolution with different aspect ratios of axes). The grains are moving under influence of three forces: aero- dynamic , gravitational and torque. The gas distribution (density, velocity, temperature) in the coma is taken from the Euler solution for spherical expansion. The aerodynamic force we estimate from expressions for free molecular interaction. On the comet surface we postulate the distribution function of ejection velocity and the distribution function of initial orientation of the grains. From the same origin on the surface we trace a number of grain trajectories with different initial conditions. Then we derive an average trajectory with mean parameters and the dispersion around it. We evaluate the goodness of spherical grain approximation through the deviation of the spherical grain trajectory from the averaged trajectory. Results. We have studied various distribution functions of initial orientation of aspherical rotating grains. The results of our simulations show that the dynamics of aspherical grains is very sensitive to the initial parameters (orientation and ejection velocity). Therefore, we see that the velocity along the trajectory of the identical aspherical grains could change

  8. 高斯光束非球面镜整形系统的设计%Design of Aspherics Lenses Shaping System on Gaussian Beam

    Institute of Scientific and Technical Information of China (English)

    冯科; 李劲松

    2013-01-01

    Application value of the Gaussian beam with flat-top shaping and some main shaping methods were introduced. Because of the advantages of aspherics, aspherics shaping method was studied, Fermi Dirac function was chosen as a flat-top beam distribution model, and the relationship between its flat-top distribution and the characteristic parameters was analyzed. By analyzing aspherics shaping principle theoretically, according to the law of conservation of energy and ray tracing function, aspheric surface form expression was deduced. Considering the processing factors, the effects of system parameters on the spherical degree was analyzed. And then, by choosing appropriate parameters, MATLAB software was used to solve numerical solution of mapping relation and surface shape curve and fit to get aspheric coefficient. By using ZEMAX optical software to make system modeling, the output beam of light intensity distribution and propagation characteristic could be gotten through the physical optics propagate-POP simulation. As a result, output beam of the flat-top quality is close to the expected effect, and its error mainly comes from numerical calculation accuracy and edge diffraction.%  首先介绍了高斯光束平顶整形的应用价值及一些主要整形方法,由于非球面镜整形的优点,本文研究非球面镜整形法。选择费米-狄拉克函数作为平顶光束模型,并分析了其平顶分布与特性参数之间的关系。理论分析了非球面镜整形原理,根据能量守恒定律和光线追迹函数推导出非球面面形表达式。考虑到加工因素,分析了影响非球面度的系统参数,根据分析,选择适当的参数,用 MATLAB 软件对映射关系和面形曲线进行数值求解并拟合得到非球面系数。用ZEMAX光学软件对整形系统进行建模,通过物理光学传播POP仿真可以得到输出光束的光强分布和传输特性,结果输出光束的平顶质量接近理论上的预期

  9. 21 CFR 886.4300 - Intraocular lens guide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraocular lens guide. 886.4300 Section 886.4300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4300 Intraocular lens guide. (a) Identification. An intraocular lens guide is a device...

  10. 21 CFR 886.5916 - Rigid gas permeable contact lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rigid gas permeable contact lens. 886.5916 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5916 Rigid gas permeable contact lens. (a) Identification. A rigid gas permeable contact lens is a device intended to be worn...

  11. 21 CFR 800.10 - Contact lens solutions; sterility.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Contact lens solutions; sterility. 800.10 Section...) MEDICAL DEVICES GENERAL Requirements for Specific Medical Devices § 800.10 Contact lens solutions... ophthalmic use, including contact lens solutions, should be sterile. It is further evident that...

  12. 人工晶状体植入术治疗白内障对视觉质量的影响分析%Effect of Intraocular Lens Implantation on the Visual Quality of Cataract

    Institute of Scientific and Technical Information of China (English)

    王雪娇

    2016-01-01

    目的:探讨人工晶状体植入术治疗白内障对视觉质量的影响。方法将106例老年性白内障患者分为研究组(非球面人工晶状体植入术)与对照组(球面人工晶状体植入术),对比治疗效果。结果研究组视觉质量优于对照组(P<0.05),视功能优良率92.5%高于对照组的71.7%(P<0.05)。结论白内障患者采用人工晶状体植入术治疗能提升视觉质量。%ObjectiveTo investigate the effect of intraocular lens implantation for the treatment of cataract on visual quality.Methods 106 cases of senile cataract patients were divided into study group (aspheric intraocular lens implantation) and control group (spherical intraocular lens implantation),and compared the treatment effect. Results The study group with better visual quality than control group(P<0.05),the excelent and good rate was 92.5%,higher than that of the control group of 71.7% (P<0.05).Conclusion Cataract patients by intraocular lens implantation for the treatment can improve the visual quality.

  13. Solar powered desalination system using Fresnel lens

    Science.gov (United States)

    Sales, M. T. B. F.

    2016-11-01

    The Philippines is surrounded by coastal areas and these areas can be a potential source for potable water. This study aims to design and construct a solar powered desalination system using Fresnel lens. The experimental study was conducted using polluted salt water for the sample and desalination was carried out using the designed system. The desalination system was composed of the solar concentrator, solar still and the condenser system. The Fresnel lens was made of acrylic plastic and was an effective solar concentrator. Solar stills made of dark colored glass bottles were effective in absorbing the solar energy. The condenser system made of polybutylene and polystyrene were effective in condensing the vapor at ambient temperature. The shortest time of vaporization of the salt water was at 293 sec and the optimum angle of position of the lens was 36.42°. The amount of condensate collected was directly proportional to the amount of salt water in the solar still. The highest mean efficiency of the designed set-up was 34.82%. The water produced by the solar powered desalination system using Fresnel lens passed the standards set by WHO (World Health Organization) for drinking water.

  14. Intraocular lens in a fighter aircraft pilot.

    OpenAIRE

    Loewenstein, A; Geyer, O; Biger, Y; Bracha, R; Shochat, I; Lazar, M.

    1991-01-01

    A pseudophakic pilot of the Israeli air force flying an F-15 (Eagle) aircraft was followed up for three years. He experienced about 100 flying hours, 5% of the time under high g stress. The intraocular lens did not dislocate and no complications were observed. It seems that flying high performance fighter aircraft is not contraindicated in pseudophakic pilots.

  15. Contact lens wear and microbial keratitis.

    Science.gov (United States)

    Ahuja, Markanday

    2002-11-01

    Common types of contact lens are hard, rigid gas-permeable or soft lenses. Most lenses are worn on a daily basis. Cosmetic lenses are worn for non-medical indications. Microbial keratitis, a rare but most significant complication is discussed in this article. Pseudomonas aeruginosa and staphylococci are the most common organisms cause infective keratitis. Fungi and acanthamoeba are also responsible. The causes of increased susceptibility to infection are poor lens hygiene, adhesion of bacteria to lens surface and hypoxia. Preventing measures to be taken while wearing contact lens are discussed in a nutshell. Ocular pain, conjunctival infection, photophobia, epiphora and reduced vision are some of the symptoms of corneal infection. Diagnostic laboratory investigations are to be carried out immediately when a microbial corneal ulcer is suspected. Acanthamoeba can be cultured from corneal scrapes. Immunologically based fluorescein labelling techniques appear to be more sensitive than simple staining. The treatment consists of medical and surgical intervention. Corneal thinning, descemetocele formation and perforation are possible complications.

  16. Contact lens rehabilitation following repaired corneal perforations

    Directory of Open Access Journals (Sweden)

    Sreenivas V

    2006-03-01

    Full Text Available Abstract Background Visual outcome following repair of post-traumatic corneal perforation may not be optimal due to presence of irregular keratometric astigmatism. We performed a study to evaluate and compare rigid gas permeable contact lens and spectacles in visual rehabilitation following perforating corneal injuries. Method Eyes that had undergone repair for corneal perforating injuries with or without lens aspiration were fitted rigid gas permeable contact lenses. The fitting pattern and the improvement in visual acuity by contact lens over spectacle correction were noted. Results Forty eyes of 40 patients that had undergone surgical repair of posttraumatic corneal perforations were fitted rigid gas permeable contact lenses for visual rehabilitation. Twenty-four eyes (60% required aphakic contact lenses. The best corrected visual acuity (BCVA of ≥ 6/18 in the snellen's acuity chart was seen in 10 (25% eyes with spectacle correction and 37 (92.5% eyes with the use of contact lens (p Conclusion Rigid gas permeable contact lenses are better means of rehabilitation in eyes that have an irregular cornea due to scars caused by perforating corneal injuries.

  17. Magnifying perfect lens with positive refraction

    CERN Document Server

    Tyc, Tomas

    2010-01-01

    We propose a device with a positive isotropic refractive index that creates a magnified perfect real image of an optically homogeneous three-dimensional region of space within geometrical optics. Its key ingredient is a new refractive index profile that can work as a perfect lens on its own, having a very moderate index range.

  18. High Accuracy Dual Lens Transmittance Measurements

    Science.gov (United States)

    2007-08-01

    measurement of lens transmission,” Metrologia 37, 603–605 (2000). 3. B. Munro, “Quantum information processing with light and its requirement for detectors...5. N. P. Fox, “Trap detectors and their properties,” Metrologia 28, 197–202 (1991). 5402 APPLIED OPTICS Vol. 46, No. 22 1 August 2007 6. S. L

  19. Testing and inspecting lens by holographic means

    Science.gov (United States)

    Hildebrand, Bernard P.

    1976-01-01

    Processes for the accurate, rapid and inexpensive testing and inspecting of oncave and convex lens surfaces through holographic means requiring no beamsplitters, mirrors or overpower optics, and wherein a hologram formed in accordance with one aspect of the invention contains the entire interferometer and serves as both a master and illuminating source for both concave and said convex surfaces to be so tested.

  20. Lens testing using total internal reflection holography

    Science.gov (United States)

    Hildebrand, Bernard P.

    1976-12-14

    Accurate, rapid and inexpensive testing and inspecting of lens surfaces tugh holographic means requiring no beamsplitters, mirrors or overpower optics, and wherein a hologram formed in accordance with one aspect of the invention contains the entire interferometer and serves as both a master and illuminating source for both concave and convex surfaces to be so tested.

  1. Application of optical polymers in lens design

    Science.gov (United States)

    Sultanova, Nina; Kasarova, Stefka; Nikolov, Ivan

    2016-03-01

    Optical, some thermal and elastic properties of optical polymers which are of importance in lens design are considered. Results are based on precise measurement of refraction of materials. Ultrasonic investigation of elastic moduli is carried out. Comparison to properties of Schott glasses is accomplished. Examples on the design of all-plastic and hybrid glass-plastic systems are presented.

  2. High Dk piggyback contact lens system for contact lens-intolerant keratoconus patients

    OpenAIRE

    Tomris Sengor; Sevda Aydin Kurna; Suat Aki; et al

    2011-01-01

    Tomris Sengor, Sevda Aydin Kurna, Suat Aki, Yelda ÖzkurtFatih Sultan Mehmet Training and Research Hospital, Istanbul, TurkeyBackground: The aim of the study was to examine the clinical success of high Dk (oxygen permeability) piggyback contact lens (PBCL) systems for the correction of contact lens intolerant keratoconus patients.Methods: Sixteen patients (29 eyes) who were not able to wear gas-permeable rigid lenses were included in this study. Hyper Dk silicone hydrogel (oxygen tran...

  3. Analysis of fiber lens with gradient index based on thin lens equivalence

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui-feng; GE Chun-feng; LI Shi-chen

    2006-01-01

    Theoretical analysis of the fiber-lens TEC (Thermally Expended Core) /Coreless/GRIN (Graded-Index) based on thin lens equivalence is presented in this paper.On condition that the TEC part adjusts the waist radius of an incident Gaussian beam,that the coreless part controlls the space between the beam waist and the thin lens,and that the GRIN part acts as the thin lens with its focal length determined by fiber index distribution parameter g,the analytic expressions of the waist spot size and the working distance of the output Gaussian beam are derived,and the influence of the coreless fiber and the length of the GRIN fiber upon the fiber-lens parameter is discussed based on the numerical simulation results.It is concluded that,if a GRIN style fiber-lens is used as a collimator,the maximum of the spot waist can be up to 80 μm and the divergence angle of single-mode optical fiber can be reduced by 8 times.If it is applied to a MEMS device, the maximum working distance can be up to 3 mm.

  4. Gram negative bacteria and contact lens induced acute red eye

    Directory of Open Access Journals (Sweden)

    Sankaridurg Padmaja

    1996-01-01

    Full Text Available Two patients using hydrogel contact lenses on a daily wear schedule slept overnight with the lenses and woke up with a Contact Lens Induced Acute Red Eye (CLARE. The contact lenses recovered aseptically at the time of the event grew significant colonies of Pseudomonas aeruginosa and Aeromonas hydrophila in patient A and Pseudomonas aeruginosa and Serratia liquefaciens from patient B. Similar organisams from the contact lenses were recovered from the lens case and lens care solutions of patient B. In both the patients the condition resolved on discontinuation of lens wear. Patient compliance as a requirement for successful contact lens wear is highlighted with the illustration of these cases.

  5. Liquid bridge as a tunable-focus cylindrical liquid lens

    Science.gov (United States)

    Chen, H.; Tabatabaei, N.; Amirfazli, A.

    2017-01-01

    We proposed a method to create a tunable-focus cylindrical liquid lens using a liquid bridge between two narrow surfaces. Due to the surface edge effect, the interface of the liquid bridge (on the long side) was shown to be able to serve as a tunable-focus cylindrical liquid lens. The working distance of the lens can be adjusted by changing either or both of the height of the bridge (H) and the volume of the liquid (V). By varying H and V, the lens can serve as either diverging or converging lens, with a minimum working distance of 2.11 mm.

  6. Acid phosphatase and lipid peroxidation in human cataractous lens epithelium

    Directory of Open Access Journals (Sweden)

    Vasavada Abhay

    1993-01-01

    Full Text Available The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium. In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium. From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

  7. Depth of focus in spherical and aspheric intraocular lenses%球面与非球面人工晶状体焦深研究

    Institute of Scientific and Technical Information of China (English)

    南莉; 汤欣; 刘永基

    2012-01-01

    目的 利用眼模型研究球面和非球面人工晶状体(IOL)眼模型焦深.方法 计算机数值模拟实验研究.以Liou-Brennan眼模型为基础在ZEMAX光学设计软件中建立IOL眼模型,模拟植入不同球面和非球面IOL离焦调制传递函数(MTF)曲线,分析瞳孔、非球面设计因素对焦深的影响.结果 550 nm单色光下,球面和非球面IOL眼焦深均随瞳孔直径缩小而增加(FY60AD眼模型6 mm瞳孔1.20D,5 mm瞳孔1.35 D,4mm瞳孔1.70 D,3 mm瞳孔2.46 D; YA60BBR眼模型6 mm瞳孔1.24D,5 mm瞳孔1.48 D,4 mm瞳孔1.80 D,3mm瞳孔2.50 D),球面IOL在负离焦一侧MTF曲线较高,瞳孔直径较大时明显.5 mm瞳孔下消球差的非球面IOL眼在良好聚焦条件下MTF高于球面IOL眼,但焦深小于球面IOL眼(Tecnis Z9000为1.31 D,FY60AD为1.35 D,CeeOn911为1.55 D,YA60BBR为1.48 D),零球差IOL眼焦深降低程度较小(LI61AO为1.42 D).结论 小瞳孔下IOL眼焦深较大,大瞳孔时良好聚焦的非球面IOL眼图像质量高于球面IOL眼,但损失部分焦深,对离焦的耐受能力下降,负离焦时明显.%Objective To investigate depth of focus (DOF) in spherical and aspheric IOL eye models.Methods Computer numerical simulation experiment was used.IOL eye model based on LiouBrennan eye model was constructed by using ZEMAX optical design software.Different IOL were implanted in this eye model Monochromatic through focus modulation transfer function (MTF) curves were computed.Pupil and aspheric designs' effect on DOF were analyzed.Results DOF of eye model increased with pupil shrinkage in 550 nm monochromatic light ( FY60AD 1.20 D at 6 mm pupil,1.35 D at 5 mm pupil,1.70 D at 4 mm pupil,2.46 D at 3 mm pupil; YA60BBR 1.24 D at 6 mm pupil,1.48 D at 5 mm pupil,1.80 D at 4 mm pupil,2.50 D at 3 mm pupil).MTF in spherical IOL eye model was higher with minus defocus,this trend was obvious at larger pupil MTF of aspheric IOL eyes were higher than spherical IOL eyes when well focused at 5 mm pupil,while the

  8. Hypoplastic basement membrane of the lens anlage in the inheritable lens aplastic mouse (lap mouse).

    Science.gov (United States)

    Aso, S; Baba, R; Noda, S; Ikuno, S; Fujita, M

    2000-04-01

    Adult homozygous lap mice show various eye abnormalities such as aphakia, retinal disorganization, and dysplasia of the cornea and anterior chamber. In the fetal eye of a homozygous lap mouse, the lens placode appears to develop normally. However, the lens vesicle develops abnormally to form a mass of cells without a cavity, and the mass vanishes soon afterward. Apoptotic cell death is associated with the disappearance of the lens anlage. We examined the basement membranes of the lens anlage of this mutant by immunohistochemical methods under light microscopy using antibodies against basement membrane components of the lens anlage, type IV collagen, fibronectin, laminin, heparan sulfate proteoglycan, and entactin and by transmission electron microscopy. Immunohistochemistry showed the distribution and intensity of antibody binding to the lens anlage to be almost the same for each these antibodies regardless of the stage of gestation or whether the anlagen were from normal BALB/c or lap mice. Thus, positive continuous reactions were observed around the exterior region of the lens anlage from day 10 of gestation for type IV collagen, fibronectin, laminin, heparan sulfate proteoglycan antibodies, and at least from day 11of gestation for entactin antibody. The basement membrane lamina densa of both normal and lap mice was shown by electron microscopy to be discontinuous at days 10 and 10.5 of gestation. However, by day 11 the lamina densa was continuous in the lens anlagen of normal mice but still discontinuous in the lap mice. By day 12 of gestation, the lamina densa had thickened markedly in normal mice, whereas in lap mice it remained discontinuous and its thinness indicated hypoplasia. These results indicate that, while all basement components examined are produced and deposited in the normal region of the lens anlage in the lap mouse, the basement membrane is, for some reason, imperfectly formed. The time at which hypoplasia of the basement membrane was observed

  9. Pars Plana Vitrectomy in Treatment of Lens Injury

    Directory of Open Access Journals (Sweden)

    Remzi Avcı

    2013-01-01

    Full Text Available Lens injury due to traumas may present as loss of capsule integrity, cataract, lens subluxation, or lens luxation. In addition, lens subluxation and lens luxation may occur in pseudophakic patients due to trauma. Clear corneal, scleral or sclero-corneal phacoemulsification surgery, pars plana vitrectomy, pars plana vitrectomy with phaco-fragmentation, or pars plana vitrectomy with removal through corneal incision techniques are used in the treatment of lens injury due to traumas. Intraocular lens can be implanted in the bag, sulcus, or anterior chamber during the surgery. Depending on the circumstances, scleral fixated intraocular lenses or iris-claw lenses may also be preferred. Rehabilitation of such patients is not of a great concern today, with the advanced level of vitreoretinal surgery and cataract surgery techniques and with the current state of technology. (Turk J Ophthalmol 2013; 43: 51-4

  10. Method and apparatus for sputtering with a plasma lens

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2016-09-27

    A plasma lens for enhancing the quality and rate of sputter deposition onto a substrate is described herein. The plasma lens serves to focus positively charged ions onto the substrate while deflecting negatively charged ions, while at the same time due to the line of sight positioning of the lens, allowing for free passage of neutrals from the target to the substrate. The lens itself is formed of a wound coil of multiple turns, inside of which are deposed spaced lens electrodes which are electrically paired to impress an E field overtop the B field generated by the coil, the potential applied to the electrodes increasing from end to end towards the center of the lens, where the applied voltage is set to a high potential at the center electrodes as to produce a potential minimum on the axis of the lens.

  11. Lightweight autoclavable wide-angle contact lens for vitreous surgery.

    Science.gov (United States)

    Chalam, K V; Gupta, Shailesh K; Agarwal, Swati

    2007-01-01

    The authors describe an autoclavable, self-stabilizing, lightweight wide-angle contact lens for vitrectomy. The lens has two optical pieces with perforated plastic casing to sustain a high temperature (150 degrees C) for autoclaving. The lens has a 106 degrees static and 127 degrees dynamic field of view. The footplates and reduced weight (2.4 grams) due to the plastic casing allow self-stabilization of the lens. The open lens design.with high temperature resistant plastic prevents fogging during autoclaving and surgery. The autoclavable, self-stabilizing, lightweight wide-angle contact lens allows visualization of the peripheral retina during surgery and faster sterilization by autoclaving between surgeries without the disadvantage of lens fogging.

  12. Data analysis results of the second sea trial of ambient noise imaging with acoustic lens in 2014: Two-dimensional target images affected by direction of field of view and spatial noise distribution

    Science.gov (United States)

    Mori, Kazuyoshi; Ogasawara, Hanako; Tsuchiya, Takenobu; Endoh, Nobuyuki

    2016-07-01

    An aspherical lens with an aperture diameter of 1.0 m has been designed and fabricated to develop a prototype system for ambient noise imaging (ANI). A sea trial of silent target detection using the prototype ANI system was conducted under only natural ocean ambient noise at Uchiura Bay in November 2010. It was verified that targets are successfully detected under natural ocean ambient noise, mainly generated by snapping shrimps. Recently, we have built a second prototype ANI system using an acoustic lens with a two-dimensional (2D) receiver array with 127 elements corresponding to a field of view (FOV) spanning 15° horizontally by 9° vertically. In this study, we investigated the effects of the direction of the FOV and the spatial noise distribution on the 2D target image obtained by ANI. Here, the noise sources in front of the target are called “front light”, and those at the rear of the target are called “back light”. The second sea trial was conducted to image targets arranged in the FOV and measure the positions of noise sources at Uchiura Bay in November 10-14, 2014. For front light, the pixel values in the on-target directions were greater than those in other directions owing to the dominant target scatterings. Reversely, for back light, the pixel values in the on-target directions were lower than those in other directions owing to the dominant direct noises such as “silhouette”.

  13. Lo calized high pressure near an aspheric encapsulated microbubble%非球形包膜微泡近场局部高压研究

    Institute of Scientific and Technical Information of China (English)

    邵纬航; 陈伟中

    2014-01-01

    Based on hydrodynamics, the pressure of the liquid outside an aspheric encapsulated bubble driven by ultrasound is studied, and its analytical expression is derived. Numerical simulation shows that 1) the aspheric shape of an encapsulated bubble makes little influence on the pressure of the liquid far away from the bubble;2) the pressure is extremely high at some local places of the liquid near an aspheric encapsulated bubble, and the pressure values at these places are apparently larger than those for a spherical encapsulated bubble at the same conditions. This phenomenon is of significance in the applications such as high intensity ultrasound therapy, drug delivery, cell membrane perforation, etc. As the ultrasound frequency shifts to the resonance frequency of an encapsulated bubble, or bubble shape deviates from sphericity, the localized high pressure becomes even greater.%基于流体力学,导出了超声驱动下的非球形包膜微泡的外部流体压强的解析表达式。数值模拟表明,虽然包膜微泡的非球形状对远场流体压强没有明显影响,但会造成近场局部位置有极大的流体压强,其明显高于同等条件下的球形包膜微泡周围相应位置上的流体压强。这一现象对包膜微泡的实际应用,如强超声治疗、靶向给药和细胞微穿孔等有着重要的意义。随着驱动频率向包膜微泡本征频率的靠近或微泡偏离球形程度的增大,所产生的近场局部高压也越大。

  14. Polybenzimidazole compounds

    Science.gov (United States)

    Klaehn, John R.; Peterson, Eric S.; Wertsching, Alan K.; Orme, Christopher J.; Luther, Thomas A.; Jones, Michael G.

    2010-08-10

    A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

  15. Hyperbolic metamaterial lens with hydrodynamic nonlocal response.

    Science.gov (United States)

    Yan, Wei; Mortensen, N Asger; Wubs, Martijn

    2013-06-17

    We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves of the free-electron plasma in the metal constituents. We derive the nonlocal corrections to the effective material parameters analytically, and illustrate the noticeable nonlocal effects on the dispersion curves numerically. As an application, we find that the focusing characteristics of a HMM lens in the local-response approximation and in the hydrodynamic Drude model can differ considerably. In particular, the optimal frequency for imaging in the nonlocal theory is blueshifted with respect to that in the local theory. Thus, to detect whether nonlocal response is at work in a hyperbolic metamaterial, we propose to measure the near-field distribution of a hyperbolic metamaterial lens.

  16. A polycarbonate ophthalmic-prescription lens series.

    Science.gov (United States)

    Davis, J K

    1978-08-01

    Improvements in polycarbonate material, production techniques, and scratch-resistant coatings, combined with a process-oriented design, have resulted in a precision lens series. Surface quality is comparable to that of untreated glass ophthalmic lenses. The repeatability of the process results in closely controlled axial power and off-axis performance. For most lens prescriptions, the ANSI Z80.1 optical-center specifications for prescription accuracy are maintained through a total field of view of 40 deg for an 8-mm range of center-of-rotation distances. Off-axis astigmatism is controlled for near-point seeing. The lenses are both lighter and thinner than those of crown glass. A scratch-resistant coating reduces the reflections normally associated with high-index (1.586) materials. Impact resistance exceeds that required by ANSI Z80.7 and is many times that required by ANSI Z80.1.

  17. Understanding Science Through the Computational Lens

    Institute of Scientific and Technical Information of China (English)

    Richard M. Karp

    2011-01-01

    This article explores the changing nature of the interaction between computer science and the natural and social sciences.After briefly tracing the history of scientific computation,the article presents the concept of computational lens,a metaphor for a new relationship that is emerging between the world of computation and the world of the sciences.Our main thesis is that,in many scientific fields,the processes being studied can be viewed as computational in nature,in the sense that the processes perform dynamic transformations on information represented as digital data.Viewing natural or engineered systems through the lens of their computational requirements or capabilities provides new insights and ways of thinking.A number of examples are discussed in support of this thesis.The examples are from various fields,including quantum computing,statistical physics,the World Wide Web and the Internet,mathematics,and computational molecular biology.

  18. A Lens Mapping Algorithm for Weak Lensing

    CERN Document Server

    Saini, T D; Saini, Tarun Deep; Raychaudhury, Somak

    2001-01-01

    We develop an algorithm for the reconstruction of the two-dimensional massdistribution of a cluster of galaxies from the observable distortion ofbackground galaxies. From the measured reduced shear gamma_i/(1-kappa) the lensmapping is directly obtained, from which a mass distribution is derived. Thisis unlike other methods where the convergence (kappa) is first obtained. Weshow that this method works best for sub-critical lenses but can be applied toa critical lens away from the critical lines. For finite fields the usualmass-sheet degeneracy is shown to exist in this method as well. We suggest aniterative scheme to remove the mass-sheet degeneracy for the case of asub-critical lens, in the absence of a substantial external shear. The sametechnique can be used with additional information for the case of a criticallens as well. A scheme to reduce the effects of noise is also suggested.

  19. A stereoscopic lens for digital cinema cameras

    Science.gov (United States)

    Lipton, Lenny; Rupkalvis, John

    2015-03-01

    Live-action stereoscopic feature films are, for the most part, produced using a costly post-production process to convert planar cinematography into stereo-pair images and are only occasionally shot stereoscopically using bulky dual-cameras that are adaptations of the Ramsdell rig. The stereoscopic lens design described here might very well encourage more live-action image capture because it uses standard digital cinema cameras and workflow to save time and money.

  20. Rose-K contact lens for keratoconus

    Directory of Open Access Journals (Sweden)

    Jain Arun

    2007-01-01

    Full Text Available Aim: To report clinical experience and the comparative value of axial and instantaneous topography data in fitting Rose-K design contact lenses in moderate and severe keratoconus. Materials and Methods: Thirty-eight eyes (of 23 patients with keratoconus were fitted with Rose-K design contact lenses and followed up for at least six months or more. Visual acuity with habitual vision correction available was measured. Axial and instantaneous topography maps for each eye were recorded. Contact lens wear comfort was graded on a ten point rating scale every three months. Results: Fourteen (100% moderate keratoconus eyes (average Sim K 48.61 ± 1.24D and 23 of 24 (96% of severe keratoconus eyes (average Sim K 60.88 ± 5.31D were successfully fitted with the Rose-K lenses. Final fit contact lenses in severe keratoconus had statistically significant steeper base curves compared to average axial corneal curvature than in moderate keratoconus eyes. Average simulated corneal curvature on axial maps predicted final fit contact lens base curves significantly better than on instantaneous maps. Thirty-three of the 37 eyes fitted with contact lenses maintained wear comfort over average follow up period of 13 ± 3.5 months. Conclusions: Rose-K design rigid contact lenses are successful in visually rehabilitating 100% of moderate and 96% of severe keratoconus eyes. Most patients (90% maintained contact lens wear comfort. Corneal curvature on axial maps is a better predictive of base curve of final fit contact lens.

  1. Comparison and Calibration of Mobile Phone Fisheye Lens and Regular Fisheye Lens via Equidistant Model

    Directory of Open Access Journals (Sweden)

    Cumhur Sahin

    2016-01-01

    Full Text Available Nowadays, mobile phones are more than a device that can only satisfy the communication need between people. In addition to providing ease to human lives with various applications, lens kits that can be integrated to mobile phones have recently been introduced. Fisheye lenses that are compliant with mobile phones are one of these new types of equipment. Since fisheye lenses integrated with mobile phones are lightweight and easy to use, they are advantageous. In addition to this advantage, whether fisheye lens and mobile phone combination can be used in a photogrammetric way is experimented, and if so, what will be the result. The main purpose of this study is to test fisheye lens equipment used with mobile phones. In this study, standard calibration of “Olloclip 3 in one” fisheye lens used with iPhone 4S mobile phone and “Nikon FC-E9” fisheye lens used with Nikon Coolpix8700 are compared based on equidistant model. The results of these calibrations are analyzed, using photogrammetric bundle block adjustment. This study suggests a precalibration process of these kinds of hardware for the photogrammetric process in the test field.

  2. Asphericity in the Fermi Surface and Fermi Energy of Na-K, Na-Rb and Na-Cs Binary Alloys

    Institute of Scientific and Technical Information of China (English)

    Minal H. Patel; A.M. Vora; P.N. Gajjar; A.R. Jani

    2002-01-01

    Detailed theoretical investigations into asphericity in the Fermi surface (FS) and Fermi energy (FE) ofNa1_xKx, Na1_xRbx, and Na1_xCsx binary solid solutions are carried out for the first time. The alloying behavior ofthe K, Rb, and Cs with the Na generates the Fermi surface distortion (FSD) of bce simple metals. The FS of Na-K,Na-Rb, and Na-Cs solid solution is a distorted sphere with the largest deviation along [110]. We have found that theimpact of local-field correction function on FSD is maximun at [100] point and minimum at [111] point. The exchangeand correlation effect is found to suppress the value of FE.

  3. CMB lens sample covariance and consistency relations

    Science.gov (United States)

    Motloch, Pavel; Hu, Wayne; Benoit-Lévy, Aurélien

    2017-02-01

    Gravitational lensing information from the two and higher point statistics of the cosmic microwave background (CMB) temperature and polarization fields are intrinsically correlated because they are lensed by the same realization of structure between last scattering and observation. Using an analytic model for lens sample covariance, we show that there is one mode, separately measurable in the lensed CMB power spectra and lensing reconstruction, that carries most of this correlation. Once these measurements become lens sample variance dominated, this mode should provide a useful consistency check between the observables that is largely free of sampling and cosmological parameter errors. Violations of consistency could indicate systematic errors in the data and lens reconstruction or new physics at last scattering, any of which could bias cosmological inferences and delensing for gravitational waves. A second mode provides a weaker consistency check for a spatially flat universe. Our analysis isolates the additional information supplied by lensing in a model-independent manner but is also useful for understanding and forecasting CMB cosmological parameter errors in the extended Λ cold dark matter parameter space of dark energy, curvature, and massive neutrinos. We introduce and test a simple but accurate forecasting technique for this purpose that neither double counts lensing information nor neglects lensing in the observables.

  4. Pitfalls in aphakic contact lens fitting

    Directory of Open Access Journals (Sweden)

    Dada Vijay

    1990-01-01

    Full Text Available We examined 23 consecutive cases of unilateral aphakia reporting to the contact lens office for endothelial count and morphology, corneal thickness and toricity. The fellow eye served as a control in all the cases. It was found that there is a significant drop in the central endothelial cell density, and change in the size and shape of the cells. These observations indicate a thermodynamically unstable state. The aphakic corneas were thicker than the controls but not to a significant extent. The cell count and pachymetry had no statistical correlation. Toricity of the aphakic corneas make successful fitting of a lens difficult. Since prolonged use of extended wear gas permeable as well as hydrogel lenses have a deleterious effect on the endothelium it is suggested that a careful case selection be made and strict monitoting carried out at follow up. These corneas are liable for decompensation with only mild noxious stimuli. This article is intended to acquaint the ophthalmologist with the pitfalls in aphakic contact lens fitting so that a cautious follow up may be planned.

  5. Adaptive Liquid Lens Actuated by Droplet Movement

    Directory of Open Access Journals (Sweden)

    Chao Liu

    2014-08-01

    Full Text Available In this paper we report an adaptive liquid lens actuated by droplet movement. Four rectangular PMMA (Polymethyl Methacrylate substrates are stacked to form the device structure. Two ITO (Indium Tin Oxide sheets stick on the bottom substrate. One PMMA sheet with a light hole is inserted in the middle of the device. A conductive droplet is placed on the substrate and touches the PMMA sheet to form a small closed reservoir. The reservoir is filled with another immiscible non-conductive liquid. The non-conductive liquid can form a smooth concave interface with the light hole. When the device is applied with voltage, the droplet stretches towards the reservoir. The volume of the reservoir reduces, changing the curvature of the interface. The device can thus achieve the function of an adaptive lens. Our experiments show that the focal length can be varied from −10 to −159 mm as the applied voltage changes from 0 to 65 V. The response time of the liquid lens is ~75 ms. The proposed device has potential applications in many fields such as information displays, imaging systems, and laser scanning systems.

  6. Achromobacter xylosoxidans keratitis after contact lens usage.

    Science.gov (United States)

    Park, Jung Hyun; Song, Nang Hee; Koh, Jae Woong

    2012-02-01

    To report on Achromobacter xylosoxidans keratitis in two healthy patients who had worn contact lenses foran extended period of time. A 36-year-old female and a 21-year-old female visited our hospital with ocular pain and blurred vision. Both patients had a history of wearing soft contact lenses for over fve years with occasional overnight wear. At the initial presentation, a slit lamp examination revealed corneal stromal infiltrations and epithelial defects with peripheral neovascularization in both patients. Microbiological examinations were performed from samples of corneal scrapings, contact lenses, contact lens cases, and solution. The culture resulting from the samples taken from the contact lenses, contact lens cases, and solution were all positive for Achromobacter xylosoxidans. Confrming that the direct cause of the keratitis was the contact lenses, the frst patient was prescribed ceftazidime and amikacin drops sensitive to Achromobacter xylosoxidans. The second patient was treated with 0.3% gatifoxacin and fortifed tobramycin drops. After treatment, the corneal epithelial defects were completely healed, and subepithelial corneal opacity was observed. Two cases of Achromobacter xylosoxidans keratitis were reported in healthy young females who wore soft contact lenses. Achromobacter xylosoxidans should be considered a rare but potentially harmful pathogen for lens-induced keratitis in healthy hosts.

  7. Ultrasound field measurement using a binary lens

    CERN Document Server

    Clement, Gregory T; Kamakura, Tomoo

    2014-01-01

    Field characterization methods using a scattering target in the absence of a point-like receiver have been well described in which scattering is recorded by a relatively large receiver located outside the field of measurement. Unfortunately, such methods are prone to artifacts due to averaging across the receiver surface. To avoid this problem while simultaneously increasing the gain of a received signal, the present study introduces a binary plate lens designed to focus spherically-spreading waves onto a planar region having a nearly-uniform phase proportional to that of the target location. The lens is similar to a zone plate, but modified to produce a bi-convex-like behavior, such that it focuses both planar and spherically spreading waves. A measurement device suitable for characterizing narrowband ultrasound signals in air is designed around this lens by coupling it to a target and planar receiver. A prototype device is constructed and used to characterize the field of a highly-focused 400 kHz air transd...

  8. Rho GTPase inactivation impairs lens growth and integrity.

    Science.gov (United States)

    Rao, Vasantha; Wawrousek, Eric; Tamm, Ernst R; Zigler, Samuel

    2002-02-01

    To elucidate the significance of Rho GTPase signaling on lens growth and structural integrity, we have selectively inactivated Rho GTPase in the ocular lens. To achieve this tissue-specific inactivation, a transgene encoding the C3-exoenzyme from Clostridium botulinum has been expressed in mice under transcriptional control of the lens-specific alphaA-crystallin promoter. C3-exoenzyme is known to selectively inactivate all Rho GTPase isoforms by ADP-ribosylating an asparagine residue at position 41. Mice expressing the C3-exoenzyme transgene exhibited selective ocular defects, including cataract and microphthalmia. Extralenticular effects included ocular hemorrhage (blood accumulation in the anterior and posterior chambers of the eye) and abnormalities of the iris including focal attachments to lens and cornea (synechiae). C3-transgene expression was found only in the lens and not in the other ocular tissues as determined by RT-PCR analysis. Histologic examination of the eyes of C3 transgenic mice from two independent lines revealed extensive abnormalities of the lens, including defective fiber cell differentiation and elongation, ruptured posterior lens capsule, and thickened anterior lens capsule. Electron microscopic analysis of hemorrhaged C3 eyes showed abnormalities in the posterior hyaloid vessels. Collectively these data reveal the importance of Rho GTPase signaling in regulating lens growth and maintenance of lens transparency.

  9. Compound Refractive Lenses for Thermal Neutron Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gary, Charles K.

    2013-11-12

    This project designed and built compound refractive lenses (CRLs) that are able to focus, collimate and image using thermal neutrons. Neutrons are difficult to manipulate compared to visible light or even x rays; however, CRLs can provide a powerful tool for focusing, collimating and imaging neutrons. Previous neutron CRLs were limited to long focal lengths, small fields of view and poor resolution due to the materials available and manufacturing techniques. By demonstrating a fabrication method that can produce accurate, small features, we have already dramatically improved the focal length of thermal neutron CRLs, and the manufacture of Fresnel lens CRLs that greatly increases the collection area, and thus efficiency, of neutron CRLs. Unlike a single lens, a compound lens is a row of N lenslets that combine to produce an N-fold increase in the refraction of neutrons. While CRLs can be made from a variety of materials, we have chosen to mold Teflon lenses. Teflon has excellent neutron refraction, yet can be molded into nearly arbitrary shapes. We designed, fabricated and tested Teflon CRLs for neutrons. We demonstrated imaging at wavelengths as short as 1.26 ? with large fields of view and achieved resolution finer than 250 μm which is better than has been previously shown. We have also determined designs for Fresnel CRLs that will greatly improve performance.

  10. 碳化硅凸非球面反射镜的加工与检测%Fabrication and test of SiC convex aspheric mirror

    Institute of Scientific and Technical Information of China (English)

    李俊峰

    2014-01-01

    In order to satisfy all-frequency error quality controlling and high-precision test during the process of the convex asphere , double laps with polar coordinate polishing technique and the measuring poles method used for the alignment of Hindle test are proposed .Firstly, the double laps with polar coordinate polishing technique for manufacturing the aspheric mirror and the numerical control machine for processing aspheric sur -face are presented .Then, the measuring poles method used to control the distances between vertex of the standard sphere and the vertex and focus of the tested asphere is introduced , and the controlling precision is analyzed.Finally, for a convex asphere with the aperture of Φ158 mm, the test results and precision of the Hindle test are described .The results indicate that the double laps polishing technique can make the low-fre-quency surface error convergence quickly , and the mid-frequency surface error is restrained at the same time . The controlling precision of the low-frequency surface error is about λ/30(λ=633 nm).The limit error using the measuring poles to control the distance is ±0.065 mm, and the tolerances of the two space parameters are ±0.22 mm and ±0.30 mm, respectively .The fast manufacture and all-frequency controlling of the convex asphere are realized by the double laps with polar coordinate polishing technique , and the test result of low-frequency surface error is 0.022λ( RMS,@633 nm) in the Hindle test, which satisfies the specification re-quirements of the optical design .%为了满足凸非球面反射镜加工中的全频段质量控制及光学参数的高精度检验,提出了应用双摆轴极坐标快速非球面加工技术及测杆法控制Hindle法检测光学参数。首先,描述了双摆轴极坐标快速非球面加工技术及设备;然后,介绍了应用测杆法控制Hindle检测法中标准球面镜顶点分别与被检非球面镜顶点及其焦点的光学间隔,并对其控制

  11. Novel Scanning Lens Instrument for Evaluating Fresnel Lens Performance: Equipment Development and Initial Results (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Herrero, R.; Miller, D. C.; Kurtz, S. R.; Anton, I.; Sala, G.

    2013-07-01

    A system dedicated to the optical transmittance characterization of Fresnel lenses has been developed at NREL, in collaboration with the UPM. The system quantifies the optical efficiency of the lens by generating a performance map. The shape of the focused spot may also be analyzed to understand change in the lens performance. The primary instrument components (lasers and CCD detector) have been characterized to confirm their capability for performing optical transmittance measurements. Measurements performed on SoG and PMMA lenses subject to a variety of indoor conditions (e.g., UV and damp heat) identified differences in the optical efficiency of the evaluated lenses, demonstrating the ability of the Scanning Lens Instrument (SLI) to distinguish between the aged lenses.

  12. Astigmatism management in cataract surgery with Precizon® toric intraocular lens: a prospective study

    Science.gov (United States)

    Vale, Carolina; Menezes, Carlos; Firmino-Machado, J; Rodrigues, Pedro; Lume, Miguel; Tenedório, Paula; Menéres, Pedro; Brochado, Maria do Céu

    2016-01-01

    Purpose The purpose of this study was to evaluate the visual and refractive outcomes and rotational stability of the new aspheric Precizon® toric intraocular lens (IOL) for the correction of corneal astigmatism in cataract surgery. Setting Department of Ophthalmology, Hospital Geral de Santo António – Centro Hospitalar do Porto, EPE and Hospital de Pedro Hispano, Matosinhos, Portugal. Design This was a prospective clinical study. Patients and methods A total of 40 eyes of 27 patients with corneal astigmatism greater than 1.0 diopter (D) underwent cataract surgery with implantation of Precizon® toric IOL. IOL power calculation was performed using optical coherence biometry (IOLMaster®). Outcomes of uncorrected (UDVA) and best-spectacle corrected distance visual acuities (BCDVA), refraction, and IOL rotation were analyzed at the 1st week, 1st, 3rd, and 6th month’s evaluations. Results The median postoperative UDVA was better than preoperative best-spectacle corrected distance visual acuity (0.02 [0.06] logMAR vs 0.19 [0.20] logMAR, P<0.001). At 6 months, postoperative UDVA was 0.1 logMAR or better in 95% of the eyes. At last follow-up, the mean spherical equivalent was reduced from −3.35±3.10 D to −0.02±0.30 D (P<0.001) with 97.5% of the eyes within ±0.50 D of emmetropia. The mean preoperative keratometric cylinder was 2.34±0.95 D and the mean postoperative refractive cylinder was 0.24±0.27 D (P<0.001). The mean IOL rotation was 2.43°±1.55°. None of the IOLs required realignment. Conclusion Precizon® toric IOL revealed very good rotational stability and performance regarding predictability, efficacy, and safety in the correction of preexisting regular corneal astigmatism associated with cataract surgery. PMID:26855559

  13. Multipurpose Compound

    Science.gov (United States)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  14. Forensic Analysis of a Contact Lens in a Murder Case.

    Science.gov (United States)

    Zwerling, Charles S

    2016-03-01

    Contact lenses have had rare relevance in trials and/or investigations. After 5 years of burial, orbital remnants were retrieved from an exhumed body and subsequently identified as a key piece of material evidence in a murder trial. The exhumed case materials were evaluated under laboratory conditions and were determined to be contact lens remnants. Contact lens fracture and burial simulation studies were performed to provide additional corroboration of the physical findings of the exhumed contact lens remnants. This material evidence was instrumental in providing factual proof refuting the defendant's testimony in the murder trial. A brief history of contact lens composition and use is provided for understanding the methods and observational results. This forensic case study represents the first published documentation of a contact lens from an exhumed body being used in a murder investigation and establishes an operational procedure for future forensic contact lens examinations.

  15. Spatial distribution of metabolites in the human lens.

    Science.gov (United States)

    Tamara, Semen O; Yanshole, Lyudmila V; Yanshole, Vadim V; Fursova, Anjella Zh; Stepakov, Denis A; Novoselov, Vladimir P; Tsentalovich, Yuri P

    2016-02-01

    Spatial distribution of 34 metabolites along the optical and equatorial axes of the human lens has been determined. For the majority of metabolites, the homogeneous distribution has been observed. That suggests that the rate of the metabolite transformation in the lens is low due to the general metabolic passivity of the lens fiber cells. However, the redox processes are active in the lens; as a result, some metabolites, including antioxidants, demonstrate the "nucleus-depleted" type of distribution, whereas secondary UV filters show the "nucleus-enriched" type. The metabolite concentrations at the lens poles and equator are similar for all metabolites under study. The concentric pattern of the "nucleus-depleted" and "nucleus-enriched" distributions testifies that the metabolite distribution inside the lens is mostly governed by a passive diffusion, relatively free along the fiber cells and retarded in the radial direction across the cells. No significant difference in the metabolite distribution between the normal and cataractous human lenses was found.

  16. Lens rigidity with trapped geodesics in two dimensions

    CERN Document Server

    Croke, Christopher B

    2011-01-01

    We consider the scattering and lens rigidity of compact surfaces with boundary that have a trapped geodesic. In particular we show that the flat cylinder and the flat M\\"obius strip are determined by their lens data. We also see by example that the flat M\\"obius strip is not determined by it's scattering data. We then consider the case of negatively curved cylinders with convex boundary and show that they are lens rigid.

  17. The action of selenite on ATP synthesis in rat lens

    OpenAIRE

    Adamchak, Marsha Ann

    1986-01-01

    A subcutaneous injection of sodium selenite (30 umol/kg body weight) in 10â day old rats produced a cataract within 72 hours. Lens opacification was preceded by a 15% decrease in ATP content. Lens ATP did not fully recover to control concentrations by 11 days postâ injection. A moderate correlation existed between lens weight and total ATP content in control lenses

  18. Effects of Coupling Lens on Optical Refrigeration of Semiconductors

    Institute of Scientific and Technical Information of China (English)

    DING Kai; ZENG Yi-Ping

    2008-01-01

    Optical refrigeration of semiconductors is encountering efficiency difficulties caused by nonradiative recombination and luminescence trapping.A commonly used approach for enhancing luminescence efficiency of a semiconductor device is coupling a lens with the device. We quantitatively study the effects of a coupling lens on optical refrigeration based on rate equations and photon recycling,and calculated cooling efficiencies of different coupling mechanisms and of different lens materials.A GaAs/GaInP heterostructure coupled with a homo-epitaxial GaInP hemispherical lens is recommended.

  19. 600 Volt Stretched Lens Array for Solar Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ENTECH, Auburn, NASA, and others have recently developed a new space photovoltaic array called the Stretched Lens Array (SLA), offering unprecedented performance...

  20. Electromagnetic Mathematical Modeling of 3D Supershaped Dielectric Lens Antennas

    Directory of Open Access Journals (Sweden)

    L. Mescia

    2016-01-01

    Full Text Available The electromagnetic analysis of a special class of 3D dielectric lens antennas is described in detail. This new class of lens antennas has a geometrical shape defined by the three-dimensional extension of Gielis’ formula. The analytical description of the lens shape allows the development of a dedicated semianalytical hybrid modeling approach based on geometrical tube tracing and physical optic. In order to increase the accuracy of the model, the multiple reflections occurring within the lens are also taken into account.

  1. Lens regeneration in axolotl: new evidence of developmental plasticity

    Directory of Open Access Journals (Sweden)

    Suetsugu-Maki Rinako

    2012-12-01

    Full Text Available Abstract Background Among vertebrates lens regeneration is most pronounced in newts, which have the ability to regenerate the entire lens throughout their lives. Regeneration occurs from the dorsal iris by transdifferentiation of the pigment epithelial cells. Interestingly, the ventral iris never contributes to regeneration. Frogs have limited lens regeneration capacity elicited from the cornea during pre-metamorphic stages. The axolotl is another salamander which, like the newt, regenerates its limbs or its tail with the spinal cord, but up until now all reports have shown that it does not regenerate the lens. Results Here we present a detailed analysis during different stages of axolotl development, and we show that despite previous beliefs the axolotl does regenerate the lens, however, only during a limited time after hatching. We have found that starting at stage 44 (forelimb bud stage lens regeneration is possible for nearly two weeks. Regeneration occurs from the iris but, in contrast to the newt, regeneration can be elicited from either the dorsal or the ventral iris and, occasionally, even from both in the same eye. Similar studies in the zebra fish concluded that lens regeneration is not possible. Conclusions Regeneration of the lens is possible in the axolotl, but differs from both frogs and newts. Thus the axolotl iris provides a novel and more plastic strategy for lens regeneration.

  2. An Ultrasonic Lens Design Based on Prefractal Structures

    Directory of Open Access Journals (Sweden)

    Sergio Castiñeira-Ibáñez

    2016-04-01

    Full Text Available The improvement in focusing capabilities of a set of annular scatterers arranged in a fractal geometry is theoretically quantified in this work by means of the finite element method (FEM. Two different arrangements of rigid rings in water are used in the analysis. Thus, both a Fresnel ultrasonic lens and an arrangement of rigid rings based on Cantor prefractals are analyzed. Results show that the focusing capacity of the modified fractal lens is better than the Fresnel lens. This new lens is believed to have potential applications for ultrasonic imaging and medical ultrasound fields.

  3. Lens regeneration in mice under the influence of vitamin A

    Indian Academy of Sciences (India)

    Digvijay Singh Shekhawat; O P Jangir; Acharya Prakash; Suthar Pawan

    2001-12-01

    The effect of vitamin A has been studied on lens regeneration in young (7 days old) as well as adult mice. A longitudinal slit was made under local anesthesia in the cornea over the lens. The lens was extracted intact through the incision. Intraperitonial injection of vitamin A (0.05 ml of 30 IU/ml in young and 0.05 ml of 50 IU/ml in adult) was given to the operated animals. Vitamin A was found to induce lens regeneration in not only young but also in adult mice. Regenerated lenses were similar in shape, size, transparency and histological features to normal intact lenses.

  4. A Novel Fisheye-Lens-Based Photoacoustic System

    Science.gov (United States)

    Choi, Hojong; Ryu, Jaemyung; Kim, Jungsuk

    2016-01-01

    This paper presents a novel fisheye-lens-based photoacoustic (PA) system. In conventional PA systems, mechanical motors are utilized to obtain the target information due to the small fields of view of such systems. The use of such motors introduces mechanical noise, which is difficult to remove when processing the echo signals. A fisheye lens system offering a wide field of view would effectively reduce the motor effects (i.e., the noise) and enable the system to have a wide field of view. Therefore, in this work, we propose a novel fisheye lens scheme and describe a PA system based on the developed lens scheme. In addition, to confirm the feasibility of the fisheye-lens-based PA system, we present the typical pulse-echo responses obtained using a 20 MHz single element immersion transducer and the echo signals measured from bull’s eye tissue samples separated by approximately 4, 6, 8, and 10 cm diagonally and 2 cm vertically from the fisheye lens. The experimental results demonstrate that the echo signal amplitudes, their center frequencies, and the −6 dB bandwidths obtained using red, green, and blue lights and a fisheye lens are acceptable when the fisheye lens is separated from a sample both diagonally and vertically. Therefore, fisheye-lens-based PA systems could be a potential method of achieving wide fields of view while reducing the mechanical motor effects. PMID:27999376

  5. INHIBITION OF RAT LENS ALDOSE REDUCTASE BY QUERCETAGETIN AND PATULETIN

    Institute of Scientific and Technical Information of China (English)

    1991-01-01

    In this paper the results of inhibition of the Aldose reductase(AR) activity on Wistar rat lens by Quercetagetin extracted from Tagetes erects Linn and by Patuletin extracted from Tagetes patula Linn are reported.Quercetagetin inhibited AR of the rat lens by 93.9% at 10~(-4)M, 76.0% at 10~(-5)M and 13.3% at 10~(-6)M. Patuletin inhibited AR of the rat lens by 100% at 10~(-1)M, 80% at 10~(-5)M and 22.7% at 10~(-6)M respectively. The results show that these two flavones are lens AR Inhibitors, but further ...

  6. Patient comfort following thirty minutes of lens wear: piggy-back versus conventional rigid-lens wear

    Directory of Open Access Journals (Sweden)

    W. D.H. Gillan

    2014-08-01

    Full Text Available Discomfort when wearing contact lenses, especially rigid contact lenses, is a common complaint amongst neophyte as well as experienced contact lens wearers. Wearing a piggy-back system of contact lenses has been shown to improve comfort and wearing time, especially in keratoconic subjects. Twenty two normal subjects wore a rigid lens or a piggy-back system of lenses for thirty minutes and after a thirty minute break swopped the mode of lens wear and wore the second modality for a thirty minute period. This study suggests that a piggy-back lens system provides improved comfort compared to wearing a rigid lens on its own. The order of lens wear might, however, influence the perceived comfort.

  7. Zirconium Compound with Boundless Prospects

    Institute of Scientific and Technical Information of China (English)

    LUO FangCheng; ZHENG JingYi; LV WenGuang; CHEN ZhongXi; WU FengFeng

    2001-01-01

    @@ Zirconium compound has a wide-ranging use in the field of high and new technology. It is published in 2000'CHINA HIGH AND NEW TECHNOLOGY PRODUCT CATALOGUE , CHINA HIGH and NEW TECHNOLOGY PRODUCT EXPORT CATALOGUE, and INTERNATIONAL KEY AND URGING DEVELOPMENT CATALOGUE OF PROPERTY, COMMODITY AND TECHNOLNGY Zirconia with the characteristic of electricity, magnetism, optics and mechanies, has good advantageous in making configurable ceramic and functional ceramic, such as band filter, resonator, buzzer and other electronic elements; optical lens, upholster crystallize glasses and other glass; synthetic tooth, synthetic bones and other biological ceramic products; new type axletree, engine, valve, airproof loop and other components of internal-combustion engine and steamship; ferrozirconium and other high temperature ceramic paint. It become a new material which has a wide-ranging use in the field of electron, spaceflight, aerospace, metallurgy, chemistry, biology, medicine and etc.

  8. Zirconium Compound with Boundless Prospects

    Institute of Scientific and Technical Information of China (English)

    LUO; FangCheng

    2001-01-01

    Zirconium compound has a wide-ranging use in the field of high and new technology. It is published in 2000'CHINA HIGH AND NEW TECHNOLOGY PRODUCT CATALOGUE , CHINA HIGH and NEW TECHNOLOGY PRODUCT EXPORT CATALOGUE, and INTERNATIONAL KEY AND URGING DEVELOPMENT CATALOGUE OF PROPERTY, COMMODITY AND TECHNOLNGY Zirconia with the characteristic of electricity, magnetism, optics and mechanies, has good advantageous in making configurable ceramic and functional ceramic, such as band filter, resonator, buzzer and other electronic elements; optical lens, upholster crystallize glasses and other glass; synthetic tooth, synthetic bones and other biological ceramic products; new type axletree, engine, valve, airproof loop and other components of internal-combustion engine and steamship; ferrozirconium and other high temperature ceramic paint. It become a new material which has a wide-ranging use in the field of electron, spaceflight, aerospace, metallurgy, chemistry, biology, medicine and etc.  ……

  9. FOCUSING BY A HIGH-POWER, LOW-FRESNEL-NUMBER LENS - THE FLY FACET LENS

    NARCIS (Netherlands)

    STAVENGA, DG; VANHATEREN, JH

    1991-01-01

    Diffraction by fly facet lenses has been investigated by photographing the diffraction patterns at various distances from a facet lens whose power was estimated to be 2.03 x 10(4) D. We studied three different aperture diameters with Fresnel numbers of the order of unity. A large focal shift was pro

  10. Focusing by a high-power, low-Fresnel-number lens : the fly facet lens

    NARCIS (Netherlands)

    Stavenga, D.G.; Hateren, J.H. van

    1991-01-01

    Diffraction by fly facet lenses has been investigated by photographing the diffraction patterns at various distances from a facet lens whose power was estimated to be 2.03 x 10(4) D. We studied three different aperture diameters with Fresnel numbers of the order of unity. A large focal shift was pro

  11. The BOSS Emission-Line Lens Survey. IV. : Smooth Lens Models for the BELLS GALLERY Sample

    CERN Document Server

    Shu, Yiping; Mao, Shude; Kochanek, Christopher S; Pérez-Fournon, Ismael; Oguri, Masamune; Montero-Dorta, Antonio D; Cornachione, Matthew A; Marques-Chaves, Rui; Zheng, Zheng; Brownstein, Joel R; Ménard, Brice

    2016-01-01

    We present \\textsl{Hubble Space Telescope} (\\textsl{HST}) F606W-band imaging observations of 21 galaxy-Ly$\\alpha$ emitter lens candidates in the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey (BELLS) for GALaxy-Ly$\\alpha$ EmitteR sYstems (BELLS GALLERY) survey. 17 systems are confirmed to be definite lenses with unambiguous evidence of multiple imaging. The lenses are primarily massive early-type galaxies (ETGs) at redshifts of approximately $0.55$, while the lensed sources are Ly$\\alpha$ emitters (LAEs) at redshifts from 2 to 3. Although the \\textsl{HST} imaging data are well fit by smooth lens models consisting of singular isothermal ellipsoids in an external shear field, a thorough exploration of dark substructures in the lens galaxies is required. The Einstein radii of the BELLS GALLERY lenses are on average $60\\%$ larger than those of the BELLS lenses because of the much higher source redshifts which will allow a detailed investigation of the radius evolution of the mass profile...

  12. An "ESA-affordable" Laue-lens

    DEFF Research Database (Denmark)

    Lund, Niels

    2005-01-01

    With ESA's INTEGRAL mission gamma-ray astronomy has advanced to the point where major scientific advances must be expected from detailed studies of the many new point sources. The interest in developing focusing telescopes operating in the soft gamma-ray regime up to 1 MeV is therefore mounting...... constraints of a specific medium size launch vehicle. The introduction of the lens mass as a primary design driver has some surprising effects for the choice of material for the crystals and new tradeoff considerations are introduced....

  13. LensTools: Weak Lensing computing tools

    Science.gov (United States)

    Petri, A.

    2016-02-01

    LensTools implements a wide range of routines frequently used in Weak Gravitational Lensing, including tools for image analysis, statistical processing and numerical theory predictions. The package offers many useful features, including complete flexibility and easy customization of input/output formats; efficient measurements of power spectrum, PDF, Minkowski functionals and peak counts of convergence maps; survey masks; artificial noise generation engines; easy to compute parameter statistical inferences; ray tracing simulations; and many others. It requires standard numpy and scipy, and depending on tools used, may require Astropy (ascl:1304.002), emcee (ascl:1303.002), matplotlib, and mpi4py.

  14. CATARACT SURGERY AND INTRAOCULAR LENS POWER CALCULATION IN A PATIENT WITH ANTERIOR MEGALOPHTHALMOS WITH NORMAL SIZED CRYSTALLINE LENS; CASE REPORT

    Directory of Open Access Journals (Sweden)

    Glišić Selimir

    2015-12-01

    Full Text Available Cataract surgery and intraocular lens power calculation is challenging in patients with anterior megalophthalmos and cataract, with postoperative refractive surprise frequently reported. Deep anterior chamber in these patients substantially influence effective lens position. To minimize possibility of refractive surprise, we used Haigis formula that takes into account anterior chamber depth in the lens power calculation for our patient. Cataract was managed by phakoemulsification with standard intraocular lens implanted in the capsular bag. Postoperatively, satisfying refractive result was achieved and refractive surprise was avoided.

  15. Comparison of Strong Gravitational Lens Model Software II. HydraLens: Computer-Assisted Strong Gravitational Lens Model Generation and Translation

    CERN Document Server

    Lefor, Alsn T

    2015-01-01

    The behavior of strong gravitational lens model software in the analysis of lens models is not necessarily consistent among the various software available, suggesting that the use of several models may enhance the understanding of the system being studied. Among the publicly available codes, the model input files are heterogeneous, making the creation of multiple models tedious. An enhanced method of creating model files and a method to easily create multiple models, may increase the number of comparison studies. HydraLens simplifies the creation of model files for four strong gravitational lens model software packages, including Lenstool, Gravlens/Lensmodel, glafic and PixeLens, using a custom designed GUI for each of the four codes that simplifies the entry of the model for each of these codes, obviating the need for user manuals to set the values of the many flags and in each data field. HydraLens is designed in a modular fashion, which simplifies the addition of other strong gravitational lens codes in th...

  16. Out-of-the-bag intraocular lens dislocation: outcomes of posterior chamber intraocular lens exchange, risk factors, and prevention

    Institute of Scientific and Technical Information of China (English)

    ZHENG Dan-ying; CHEN Li-na; SUN Yi; SHAO Ying-feng; LIANG Jing-li; LIU Yi-zhi

    2010-01-01

    Background Dislocation of posterior chamber intraocular lens is one of the most common complications of intraocular lens implantation. Lens exchange is an effective solution to this unsatisfactory status. This study was conducted to analyze the possible predisposing factors for out-of-the-bag posterior chamber intraocular lens dislocation and to study the outcomes of lens exchange surgery.Methods Thirty-six consecutive patients (36 eyes) with out-of-the-bag intraocular lens dislocation who underwent posterior chamber intraocular lens exchange in Zhongshan Ophthalmic Center of Sun Yat-sen University (Guangdong,China) from January 2003 to October 2009 were included. A 6-month follow-up was completed. The causes for out-of-the-bag intraocular lens dislocation and visual outcomes of posterior chamber intraocular lens exchange were analyzed. The out-of-the-bag intraocular lens dislocation was diagnosed on the basis of the findings from slit-lamp microscope and B-ultrasound. The dislocated intraocular lens was explanted. Reimplantation of a new posterior chamber intraocular lens was performed in each case using standardized surgical procedures.Results In this study, a total of thirty-six consecutive patients (36 eyes) with out-of-the-bag intraocular lens dislocation underwent posterior chamber intraocular lens exchange surgery. Causes for out-of-the-bag intraocular lens dislocation included posterior capsule rupture during the initial cataract extraction procedure (23 eyes, 63.8%), trauma (5 eyes,13.9%), neodymium-doped yttrium aluminium garnet (Nd:YAG) laser-induced dislocation (2 eyes, 5.6%), the status after vitrectomy (2 eyes, 5.6%) and unidentifiable etiology (4 eyes, 11.1%). Symptoms of these patients mainly included decrease in visual acuity (17 cases, 47.2%), blurred vision (16 cases, 44.4%), glare (1 case, 2.8%), diplopia (1 case,2.8%), and halo (1 case, 2.8%). Intraocular lens dislocation into the posterior vitreous cavity (29 eyes, 80.5%), anterior chamber (1

  17. Error Analysis and Study for Ultra-precision Aspheric Lens Based on Levenberg-marquardt Algorithm%基于Levenberg-Marquardt算法的超精密非球面镜面误差分析及研究

    Institute of Scientific and Technical Information of China (English)

    欧阳渺安; 李国旗; 陈新度

    2007-01-01

    根据超精密非球面补正加工的要求,应用误差理论及其数据处理方法对其测量数据进行了分析研究,建立了优化数学模型,采用Levenberg-Marquardt(LM)优化迭代方法对数学模型进行参数拟合求解.在VC++环境下实现该算法的程序,得出形状误差PV(Peak-Valley)值.通过分析误差曲线图,来验证优化的光学参数的正确性.实例计算表明该算法能很好的应用于超精密非球面镜面形状误差分析,为评价超精密非球面镜的加工质量和后续的补正加工提供了理论依据.

  18. Design of Object Lens for Helmet-Mounted Night Vision Goggles with High-Order Plastic Aspherical Surfaces%含高次塑料非球面的头盔微光夜视物镜设计

    Institute of Scientific and Technical Information of China (English)

    杨胜杰

    2009-01-01

    为使头盔微光夜视镜的重量更轻,同时保证其较好的成像性能,分析了光学塑料的特性及其加工,通过引入高次塑料非球面,设计了含有3个高次塑料非球面的6片式微光夜视物镜.该物镜具有大视场(40°、小F数(F/1.25)、小畸变(1%)的特点,光学传递函数在空间频率40lp/mm时,轴上传函≥0.6,轴外传函≥0.4,满足微光夜视物镜成像要求.相对具有同样性能的传统物镜系统,总长41 mm,为传统物镜的82.6%,重量13.3 g,仅为传统物镜的32.7%.为头盔式微光夜视系统减重设计提供了一个新的参考思路.

  19. Fusarium and Candida albicans biofilms on soft contact lenses: model development, influence of lens type and susceptibility to lens care solutions

    Science.gov (United States)

    Fungal keratitis is commonly caused by Fusarium species, while cases of Candida-associated keratitis are less frequent. Recent outbreaks of Fusarium keratitis were associated with contact lens wear and with MoistureLoc contact lens care solution, and biofilm formation on contact lens/lens cases was...

  20. Intermetallic Compounds

    Science.gov (United States)

    Takagiwa, Y.; Matsuura, Y.; Kimura, K.

    2014-06-01

    We have focused on the binary narrow-bandgap intermetallic compounds FeGa3 and RuGa3 as thermoelectric materials. Their crystal structure is FeGa3-type (tetragonal, P42/ mnm) with 16 atoms per unit cell. Despite their simple crystal structure, their room temperature thermal conductivity is in the range 4-5-W-m-1-K-1. Both compounds have narrow-bandgaps of approximately 0.3-eV near the Fermi level. Because their Seebeck coefficients are quite large negative values in the range 350-FeGa3 and RuGa3 as n and p-type materials. The dimensionless figure of merit, ZT, was significantly improved by substitution of Sn for Ga in FeGa3 (electron-doping) and by substitution of Zn for Ga in RuGa3 (hole-doping), mainly as a result of optimization of the electronic part, S 2 σ.

  1. High Dk piggyback contact lens system for contact lens-intolerant keratoconus patients

    Directory of Open Access Journals (Sweden)

    Tomris Sengor

    2011-03-01

    Full Text Available Tomris Sengor, Sevda Aydin Kurna, Suat Aki, Yelda ÖzkurtFatih Sultan Mehmet Training and Research Hospital, Istanbul, TurkeyBackground: The aim of the study was to examine the clinical success of high Dk (oxygen permeability piggyback contact lens (PBCL systems for the correction of contact lens intolerant keratoconus patients.Methods: Sixteen patients (29 eyes who were not able to wear gas-permeable rigid lenses were included in this study. Hyper Dk silicone hydrogel (oxygen transmissibility or Dk/t = 150 units and fluorosilicone methacrylate copolymer (Dk/t = 100 units lenses were chosen as the PBCL systems. The clinical examinations included visual acuity and corneal observation by biomicroscopy, keratometer reading, and fluorescein staining before and after fitting the PBCL system.Results: Indications for using PBCL system were: lens stabilization and comfort, improving comfort, and adding protection to the cone. Visual acuities increased significantly in all of the patients compared with spectacles (P = 0. Improvement in visual acuity compared with rigid lenses alone was recorded in 89.7% of eyes and no alteration of the visual acuity was observed in 10.3% of the eyes. Wearing time of PBCL systems for most of the patients was limited time (mean 6 months, range 3–12 months; thereafter they tolerated rigid lenses alone except for 2 patients.Conclusion: The PBCL system is a safe and effective method to provide centering and corneal protection against mechanical trauma by the rigid lenses for keratoconus patients and may increase contact lens tolerance.Keywords: piggyback contact lens, keratoconus, irregular astigmatism

  2. Compound odontoma

    Directory of Open Access Journals (Sweden)

    Monica Yadav

    2012-01-01

    Full Text Available Odontomas have been extensively reported in the dental literature, and the term refers to tumors of odontogenic origin. Though the exact etiology is still unknown, the postulated causes include: local trauma, infection, inheritance and genetic mutation. The majority of the lesions are asymptomatic; however, may be accompanied with pain and swelling as secondary complaints in some cases. Here, we report a case of a compound odontome in a 14 year old patient.

  3. Organic Compounds

    Science.gov (United States)

    Shankland, Kenneth

    For many years, powder X-ray diffraction was used primarily as a fingerprinting method for phase identification in the context of molecular organic materials. In the early 1990s, with only a few notable exceptions, structures of even moderate complexity were not solvable from PXRD data alone. Global optimisation methods and highly-modified direct methods have transformed this situation by specifically exploiting some well-known properties of molecular compounds. This chapter will consider some of these properties.

  4. Simulation model of a new solar laser system of Fresnel lens according to real observed solar radiation data in

    Directory of Open Access Journals (Sweden)

    Yasser A. Abdel-Hadi

    2015-12-01

    Full Text Available A new simulation model of a new solar pumped laser system was tested to be run in Helwan in Egypt (latitude φ = 29°52′N, longitude λ = 31°21′E and elevation = 141 m as an example of an industrial polluted area. The system is based on concentrating the solar radiation using a Fresnel lens on a laser head fixed on a mount tracking the sun during the day and powered by a DC battery. Two cases of this model are tested; the first one is the model consisting of a Fresnel lens and a two-dimensional Compound Parabolic Concentrator (CPC, while the other is the model consisting of a Fresnel lens and a three-dimensional Compound Parabolic Concentrator (CPC. The model is fed by real actual solar radiation data taken in Helwan Solar Radiation Station at NRIAG in the various seasons in order to know the laser power got from such a system in those conditions. For the system of Fresnel lens and 2D-CPC, an average laser output power of 1.27 W in Winter, 2 W in Spring, 5 W in Summer and 4.68 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 3.24 W. For the system of Fresnel lens and 3D-CPC, an average laser output power of 3.28 W in Winter, 3.55 W in Spring, 7.56 W in Summer and 7.13 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 5.38 W.

  5. Thermal behavior in the LENS process

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, M.L.; Schlienger, M.E.; Harwell, L.D. [and others

    1998-08-01

    Direct laser metal deposition processing is a promising manufacturing technology which could significantly impact the length of time between initial concept and finished part. For adoption of this technology in the manufacturing environment, further understanding is required to ensure robust components with appropriate properties are routinely fabricated. This requires a complete understanding of the thermal history during part fabrication and control of this behavior. This paper will describe research to understand the thermal behavior for the Laser Engineered Net Shaping (LENS) process, where a component is fabricated by focusing a laser beam onto a substrate to create a molten pool in which powder particles are simultaneously injected to build each layer. The substrate is moved beneath the laser beam to deposit a thin cross section, thereby creating the desired geometry for each layer. After deposition of each layer, the powder delivery nozzle and focusing lens assembly is incremented in the positive Z-direction, thereby building a three dimensional component layer additively. It is important to control the thermal behavior to reproducibly fabricate parts. The ultimate intent is to monitor the thermal signatures and to incorporate sensors and feedback algorithms to control part fabrication. With appropriate control, the geometric properties (accuracy, surface finish, low warpage) as well as the materials` properties (e.g., strength, ductility) of a component can be dialed into the part through the fabrication parameters. Thermal monitoring techniques will be described, and their particular benefits highlighted. Preliminary details in correlating thermal behavior with processing results will be discussed.

  6. Optimization of lens shape for autostereoscopic display

    Science.gov (United States)

    Su, Ping; An, Shu; Ma, Jianshe

    2016-10-01

    The three-dimensional(3D) displays based on binocular parallax have drawn increasingly interests. The light splitting element, which presents separate images to the viewer's left and right eyes, plays an important part in the auto-stereoscopic display. Lenticular lenses are widely used as the light splitting elements. However, the crosstalk resulted from the unsatisfied splitting may reduce the 3D experience. It was determined that the most suitable cross sectional shape for lenticular lenses is elliptical. Firstly, the formula of the surface is derived based on the ellipse expression and the requirement of the 3D display system, that is y2+0.5651x2 - 303.4768=0. Secondly, one axial source and 4 off-axial sources placed at the heights of 2.5mm, 5mm, 7.5mm and 8mm are used to analyze the beam splitting quality of the cylindrical and elliptical lens element, respectively. The spot of elliptical lens is smaller which means a better beam splitting quality. Thirdly, Monte Carlo Non-Sequential Ray tracing algorithm is used to simulate the luminance distribution on the viewing plane, the narrower width of vertical stripes means that the aberration is suppressed. Finally, the shape of elliptical can reduce the processing difficulty with the 10μm minimum step width. In a word, the optimization of the surface has a significant effect on the improvement of stereoscopic depth and the reduction of ghost images.

  7. What Do Gravitational Lens Time Delays Measure?

    CERN Document Server

    Kochanek, C S

    2002-01-01

    Gravitational lens time delays depend on the Hubble constant, the observed image positions, and the surface mass density of the lens in the annulus between the images. Simple time delay lenses like PG1115+080, SBS1520+530, B1600+434, PKS1830-211 and HE2149-2745 have H0 = A(1-)+B(e-1) where the two coefficients A ~ 90km/s Mpc and B ~ 10km/s Mpc depend on the measured delays and the observed image positions, is the mean surface density in the annulus between the images, and there is a small correction from the logarithmic slope e ~ 2 of the surface density profile, k ~ R^(1-e), in the annulus. These 5 systems are very homogeneous, since for fixed H0=100h km/s Mpc they must have the same surface density, =1.11-1.22 h +/- 0.04, with an upper bound of 0.07 on any dispersion in beyond those due to the measurement errors. If the lenses have their expected dark halos, ~ 0.5 and H0=51+/-5 km/s Mpc, while if they have constant mass-to-light ratios, ~ 0.1-0.2 and H0=73+/-8 km/s Mpc. More complicated lenses with mult...

  8. Pharmacognostic evaluation of Lens culinaris Medikus seeds

    Institute of Scientific and Technical Information of China (English)

    Kripi Vohra; Vivek Kumar Gupta

    2012-01-01

    Objective: To present a detailed pharmacognostic study of the Lens culinaris Medikus (Fabaceae) seeds, a food grain used as Dhal in India. Methods: The macroscopy, microscopy, fluorescence analysis of powdered drug, physicochemical analysis, preliminary testing and other WHO recommended methods for standardization were investigated. Results: Seeds are greyish brown in colour. Treatment of powdered drug with various chemical reagents showed the presence of proteins, cellulose, lignins and fixed oils. Microscopy of seeds revealed the presence of starch grains in seed. The colour of seed coat changed from brown to greenish grey in day light and brown to black at 254nm when treated with acetic acid. Total ash value of the seeds was found to be 1.86% w/w whereas foreign organic matter was found to be nil. Qualitative phytochemical analysis revealed the presence of tannins and flavonoids in acetone extract. Conclusions: The present study on pharmacognostic profile of Lens culinaris Medikus seeds provides an important tool in identification and authentication of this plant to researchers in future.

  9. Curiosity's Mars Hand Lens Imager (MAHLI) Investigation

    Science.gov (United States)

    Edgett, Kenneth S.; Yingst, R. Aileen; Ravine, Michael A.; Caplinger, Michael A.; Maki, Justin N.; Ghaemi, F. Tony; Schaffner, Jacob A.; Bell, James F.; Edwards, Laurence J.; Herkenhoff, Kenneth E.; Heydari, Ezat; Kah, Linda C.; Lemmon, Mark T.; Minitti, Michelle E.; Olson, Timothy S.; Parker, Timothy J.; Rowland, Scott K.; Schieber, Juergen; Sullivan, Robert J.; Sumner, Dawn Y.; Thomas, Peter C.; Jensen, Elsa H.; Simmonds, John J.; Sengstacken, Aaron J.; Willson, Reg G.; Goetz, Walter

    2012-09-01

    The Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) investigation will use a 2-megapixel color camera with a focusable macro lens aboard the rover, Curiosity, to investigate the stratigraphy and grain-scale texture, structure, mineralogy, and morphology of geologic materials in northwestern Gale crater. Of particular interest is the stratigraphic record of a ˜5 km thick layered rock sequence exposed on the slopes of Aeolis Mons (also known as Mount Sharp). The instrument consists of three parts, a camera head mounted on the turret at the end of a robotic arm, an electronics and data storage assembly located inside the rover body, and a calibration target mounted on the robotic arm shoulder azimuth actuator housing. MAHLI can acquire in-focus images at working distances from ˜2.1 cm to infinity. At the minimum working distance, image pixel scale is ˜14 μm per pixel and very coarse silt grains can be resolved. At the working distance of the Mars Exploration Rover Microscopic Imager cameras aboard Spirit and Opportunity, MAHLI's resolution is comparable at ˜30 μm per pixel. Onboard capabilities include autofocus, auto-exposure, sub-framing, video imaging, Bayer pattern color interpolation, lossy and lossless compression, focus merging of up to 8 focus stack images, white light and longwave ultraviolet (365 nm) illumination of nearby subjects, and 8 gigabytes of non-volatile memory data storage.

  10. Tubular astigmatism-tunable fluidic lens.

    Science.gov (United States)

    Kopp, Daniel; Zappe, Hans

    2016-06-15

    We demonstrate a new means to fabricate three-dimensional liquid lenses which may be tuned in focal length and astigmatism. Using actuation by electrowetting-on-dielectrics, astigmatism in arbitrary directions may be tuned independently, with almost no cross talk between orthogonal orientations. The lens is based on electrodes structured on planar polyimide foils and subsequently rolled, enabling high-resolution patterning of complex electrodes along the azimuthal and radial directions of the lens. Based on a design established through fluidic and optical simulations, the astigmatism tuning is experimentally verified by a change of the corresponding Zernike coefficients measured using a Shack-Hartmann wavefront sensor. It was seen that the back focal length can be tuned by 5 mm and 0° and 45° astigmatism by 3 μm through application of voltages in the range of 50  Vrms. It was observed that the cross talk with other aberrations is very low, suggesting a novel means for astigmatism control in imaging systems.

  11. Radiation dose to the eye lens

    DEFF Research Database (Denmark)

    Baun, Christina; Falch Braas, Kirsten; D. Nielsen, Kamilla;

    2015-01-01

    field in oncology patients undergoing eyes-to-thighs PET/CT must always include the base of the scull according to department guidelines. The eye lens is sensitive to radiation exposure and if possible it should be avoided to scan the eye. If the patient’s head is kipped backwards during the scan one...... might avoid including the eye in the CT scan without losing sufficient visualization of the scull base. The aim of this study was to evaluate the possibility of decreasing the radiation dose to the eye lens, simply by changing the head position, when doing the PET/CT scan from the base of the scull...... pillow below the head (standard), and (b) kipped backwards with the pillow below the neck (kipped). For each head position, CT scans were repeated 5 times with both a low dose and a high dose CT protocol; in this way, a total of 20 CT scans were performed. Robust standard errors were used in order...

  12. Scleral lens for keratoconus: technology update

    Directory of Open Access Journals (Sweden)

    Rathi VM

    2015-10-01

    Full Text Available Varsha M Rathi,1 Preeji S Mandathara,2 Mukesh Taneja,1 Srikanth Dumpati,1 Virender S Sangwan1 1L V Prasad Eye Institute, Hyderabad, India; 2School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia Abstract: Scleral lenses are large diameter lenses which rest over the sclera, unlike the conventional contact lenses which rest on the cornea. These lenses are fitted to not touch the cornea and there is a space created between the cornea and the lens. These lenses are inserted in the eyes after filling with sterile isotonic fluid. Generally, scleral contact lenses are used for high irregular astigmatism as seen in various corneal ectatic diseases such as keratoconus, pellucid marginal degeneration, or/and as liquid bandage in ocular surface disorders. In this article, we review the new developments, that have taken place over the years, in the field of scleral contact lenses as regard to new designs, materials, manufacturing technologies, and fitting strategies particularly for keratoconus. Keywords: keratoconus, scleral lens, technology update, PROSE

  13. Calcification of intraocular implant lens surfaces.

    Science.gov (United States)

    Wu, Wenju; Guan, Xiangying; Tang, Ruikang; Hook, Daniel; Yan, Wenyan; Grobe, George; Nancollas, George H

    2004-02-17

    Calcification of octacalcium phosphate [Ca8H2(PO4)6 x 5H2O, OCP] on differently packaged "Ultem" and "Surefold" intraocular implant lens surfaces has been studied in vitro in solutions supersaturated with respect to OCP at pH = 7.10 and 37 degrees C. No mineral deposition was observed on the lenses packaged in Ultem vials even after treatment with behenic acid, one of the fatty acids identified on explanted lenses. Following treatment with behenic acid, nucleation of OCP occurred on the lenses from Surefold vials, which incorporate silicone gaskets; induction periods preceding calcification were about 6 h. No mineralization was found on the lenses in vials with other gasket materials, including polytetrafluoroethylene, fluorocarbon elastomer, and polypropylene. The results of this study indicate that both silicone and fatty acids such as behenic acid play important roles in inducing the in vivo calcification of OCP on IOL lenses; all of the lens treatment steps were necessary for nucleation induction.

  14. Dose limits to the eye lens

    Energy Technology Data Exchange (ETDEWEB)

    Sion, N.

    2016-09-15

    Protecting the human body from the effects of ionizing radiation is essential to forestall stochastic effects and require placing limits on the effective dose. Dose limits on specific organs are also necessary to reduce the deterministic effects and tissue reactions. The standard for radiation protection was ISO 15382 (2002) which mainly dealt with beta radiation for nuclear power plant workers. Clearly an update is required to allow for new technology and the proliferative use of radiation in medical practices. There is a need for more explicit radiation monitoring to operators and staff. ICRP118 (International Commission on Radiological Protection), Ref. 1, evolved their recommendations to include eye lens doses as a follow on to their publication 103 and to focus on radiation exposures. It provides updated estimates of 'practical' threshold doses for tissue injury at the level of 1% incidence. This paper discusses the current status and the recommendation for a drastic reduction of the dose limit to the eye lens. (author)

  15. Curiosity's Mars Hand Lens Imager (MAHLI) Investigation

    Science.gov (United States)

    Edgett, Kenneth S.; Yingst, R. Aileen; Ravine, Michael A.; Caplinger, Michael A.; Maki, Justin N.; Ghaemi, F. Tony; Schaffner, Jacob A.; Bell, James F.; Edwards, Laurence J.; Herkenhoff, Kenneth E.; Heydari, Ezat; Kah, Linda C.; Lemmon, Mark T.; Minitti, Michelle E.; Olson, Timothy S.; Parker, Timothy J.; Rowland, Scott K.; Schieber, Juergen; Sullivan, Robert J.; Sumner, Dawn Y.; Thomas, Peter C.; Jensen, Elsa H.; Simmonds, John J.; Sengstacken, Aaron J.; Wilson, Reg G.; Goetz, Walter

    2012-01-01

    The Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) investigation will use a 2-megapixel color camera with a focusable macro lens aboard the rover, Curiosity, to investigate the stratigraphy and grain-scale texture, structure, mineralogy, and morphology of geologic materials in northwestern Gale crater. Of particular interest is the stratigraphic record of a ?5 km thick layered rock sequence exposed on the slopes of Aeolis Mons (also known as Mount Sharp). The instrument consists of three parts, a camera head mounted on the turret at the end of a robotic arm, an electronics and data storage assembly located inside the rover body, and a calibration target mounted on the robotic arm shoulder azimuth actuator housing. MAHLI can acquire in-focus images at working distances from ?2.1 cm to infinity. At the minimum working distance, image pixel scale is ?14 μm per pixel and very coarse silt grains can be resolved. At the working distance of the Mars Exploration Rover Microscopic Imager cameras aboard Spirit and Opportunity, MAHLI?s resolution is comparable at ?30 μm per pixel. Onboard capabilities include autofocus, auto-exposure, sub-framing, video imaging, Bayer pattern color interpolation, lossy and lossless compression, focus merging of up to 8 focus stack images, white light and longwave ultraviolet (365 nm) illumination of nearby subjects, and 8 gigabytes of non-volatile memory data storage.

  16. Why are there so many system shapes in lens design?

    NARCIS (Netherlands)

    Bociort, F.

    2010-01-01

    The presence of many local minima in the merit function landscape is perhaps the most difficult challenge in lens design. We present a simplified mathematical model that illustrates why the number of local minima increases rapidly with each additional lens added to the imaging system. Comparisons wi

  17. The analysis of optical wave beams propagation in lens systems

    Science.gov (United States)

    Kazakov, I.; Mosentsov, S.; Moskaletz, O.

    2016-08-01

    In this paper some aspects of the formation and propagation of optical wave beams in lens systems were considered. As an example, the two-lens optical information processing system was considered. Analysis of the two-lens optical circuit has been made with a systems approach perspective. As part of the radio-optical analogies had been applied certain provisions of the theory of dynamical systems to the spatial optical system. The lens system is represented as a simple series-connected optical elements with known spatial impulse response. General impulse response of such a system has been received, as well as consider some special cases of the impulse response. The question of the relationship between the parameters and the size of the input aperture lenses for undistorted transmission of the optical signal has been considered. Analysis of the energy loss resulting from the finite aperture of the lens. It's based on an assessment of the fraction of radiation that propagates beyond the lens. Analysis showed that the energy losses depend explicitly on the following parameters: radiation wavelength, distance between input aperture and lens, and ratio of the input aperture and lens aperture. With the computer help simulation the dependence of losses was shown on the above parameters

  18. Opaque Contact Lens For Tracking Motion Of Eye

    Science.gov (United States)

    Zografos, James L., II; Gibson, Charles R.

    1993-01-01

    Opaque contact lens facilitates measurements of movements of eye; particularly, torsional movements. Lens, marked with pair of indices at diameter of 0.5 mm, provides stable, high-contrast reference for measurements of angular position and velocity of eye by use of video-image-analysis techniques. Intended for use in experiments on response of eye to vestibular balance mechanism.

  19. Terahertz wave tomographic imaging with a Fresnel lens

    Institute of Scientific and Technical Information of China (English)

    S. Wang; X.-C. Zhang

    2003-01-01

    We demonstrate three-dimensional tomographic imaging using a Fresnel lens with broadband terahertz pulses. Objects at various locations along the beam propagation path are uniquely imaged on the same imaging plane using a Fresnel lens with different frequencies of the imaging beam. This procedure allows the reconstruction of an object's tomographic contrast image by assembling the frequency-dependent images.

  20. Secondary implantation of a double intraocular lens after penetrating keratoplasty.

    Science.gov (United States)

    Gayton, J L

    1998-02-01

    Penetrating keratoplasty (PKP) patients often have severe, visually disabling refractive errors. Astigmatism can be addressed by refractive surgery; however, correcting hyperopia is more problematic. Although pseudophakic PKP patients can have a lens exchange, it can be traumatic in this population. In this pseudophakic PKP patient, I added a second posterior chamber intraocular lens, correcting the hyperopia and resolving visual complaints.

  1. An adjustable electron achromat for cathode lens microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tromp, R.M., E-mail: rtromp@us.ibm.com [IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States); Leiden Institute of Physics, Kamerlingh Onnes Laboratory, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

    2015-12-15

    Chromatic aberration correction in light optics began with the invention of a two-color-corrected achromatic crown/flint lens doublet by Chester Moore Hall in 1730. Such color correction is necessary because any single glass shows dispersion (i.e. its index of refraction changes with wavelength), which can be counteracted by combining different glasses with different dispersions. In cathode lens microscopes (such as Photo Electron Emission Microscopy – PEEM) we encounter a similar situation, where the chromatic aberration coefficient of the cathode lens shows strong dispersion, i.e. depends (non-linearly) on the energy with which the electrons leave the sample. Here I show how a cathode lens in combination with an electron mirror can be configured as an adjustable electron achromat. The lens/mirror combination can be corrected at two electron energies by balancing the settings of the electron mirror against the settings of the cathode lens. The achromat can be adjusted to deliver optimum performance, depending on the requirements of a specific experiment. Going beyond the achromat, an apochromat would improve resolution and transmission by a very significant margin. I discuss the requirements and outlook for such a system, which for now remains a wish waiting for fulfilment. - Highlights: • The properties of cathode objective lens plus electron mirror are discussed. • In analogy with light-optical achromats, cathode lens plus mirror can be configured as an electron achromat. • Unlike light optics, the electron achromat can be adjusted to best fulfill experimental requirements.

  2. A Broadband Metasurface-Based Terahertz Flat-Lens Array

    KAUST Repository

    Wang, Qiu

    2015-02-12

    A metasurface-based terahertz flat-lens array is proposed, comprising C-shaped split-ring resonators exhibiting locally engineerable phase discontinuities. Possessing a high numerical aperture, the planar lens array is flexible, robust, and shows excellent focusing characteristics in a broadband terahertz frequency. It could be an important step towards the development of planar terahertz focusing devices for practical applications.

  3. Isofocusing and immunological investigations on cephalopod lens proteins

    NARCIS (Netherlands)

    Brahma, S.K.; Lancieri, M.

    1979-01-01

    Soluble lens proteins from Octopus vulgaris, Sepia officinalis, and Loligo vulgaris were analyzed by thin-layer isoelectric focusing and compared by various immunochemical methods using antibodies directed against total soluble lens protein antigens from the said three species. The results show clos

  4. Scleral lens tolerance after corneal cross-linking for keratoconus

    NARCIS (Netherlands)

    Visser, Esther Simone; Soeters, Nienke; Tahzib, Nayyirih G.

    2015-01-01

    Purpose. Subjective and objective evaluation of scleral lens tolerance and fitting before and after corneal cross-linking (CXL) for progressive keratoconus. Methods. In this prospective cohort, evaluations were made of 18 unilateral eyes in patients who underwent CXL and had been wearing scleral len

  5. Achromatic Fresnel Lens with Improved Efficiency for PV Systems

    Directory of Open Access Journals (Sweden)

    Mario González Montes

    2014-01-01

    Full Text Available This work is aimed to design and evaluate different achromatic Fresnel lens solutions capable of operating as concentrators aimed at photovoltaic cells systems. Throughout this study, the theoretical parametric design of the achromatic lens will be shown together with a series of simulations to verify the performance of each lens topology. The results will be compared with a standard Fresnel lens to ascertain the validity and effectiveness of the obtained design. Finally, a novel kind of hybrid lens is proposed, which combines the advantages of each type of lens (standard and Fresnel according to the optimal operating region of each design. Efficiency and concentration ratios of each particular lens are shown, regarding lens dimension, light’s incidence angle, or wavelength. Through this innovative achromatic design concentration ratios above 1000 suns, which hardly reach standard Fresnel lenses. Furthermore chromatic dispersion is minimized and the efficiency rate is over 85% of efficiency for a wide spectral range (from 350 nm to 1100 nm.

  6. Incidence of contact lens-associated microbial keratitis

    NARCIS (Netherlands)

    Cheng, K.H.; Leung, S.L.; Hoekman, J.W.; Beekhuis, W.H.; Mulder, P.G.H.; Geerards, A.J.M.; Kijlstra, A.

    1999-01-01

    Background. The incidence of contact-lens-associated microbial keratitis is uncertain and its related morbidity in the general population of contact-lens wearers is not known. We examined these issues in a prospective epidemiological study. Methods. We surveyed all practising ophthalmologists in the

  7. The NNEST lens non native english speakers in TESOL

    CERN Document Server

    Mahboob, Ahmar

    2010-01-01

    The NNEST Lens invites you to imagine how the field of TESOL and applied linguistics can develop if we use the multilingual, multicultural, and multinational perspectives of an NNEST lens to re-examine our assumptions, practices, and theories in the field

  8. Contact lens wear and dry eyes: challenges and solutions

    Directory of Open Access Journals (Sweden)

    Markoulli M

    2017-02-01

    Full Text Available Maria Markoulli, Sailesh Kolanu School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia Abstract: The number of contact lens wearers worldwide has remained relatively stable over the past decade, despite the investment that has gone into contact lens technology. This is largely because 10%–50% of wearers dropout of contact lens wear within 3 years of commencement; the most common reason cited being contact lens discomfort (CLD. Of the symptoms reported, sensation of dry eye is the most common. Given the outcome of reduced wearing time, increased chair time, and ultimate contact lens discontinuation, the challenge is to identify the warning signs of CLD early on. Clinically detectable changes such as conjunctival staining, conjunctival indentation, conjunctival epithelial flap formation, lid wiper epitheliopathy, Demodex blepharitis, and meibomian gland dysfunction have been linked to CLD, highlighting the need to perform regular aftercare visits to identify these changes. At a cellular level, conjunctival metaplasia and reduced goblet cell density have been linked to CLD, leading to a downstream effect on the tear film breakup time of contact lens wearers. These factors suggest a strong link between CLD and friction, raising the need to target this as a means of minimizing CLD. The purpose of this review is to identify the clinical signs that relate to CLD as a means of earlier detection and management in order to combat contact lens dropout. Keywords: contact lens discomfort, dry eye disease, lid wiper epitheliopathy, tear film biomarkers, meibomian gland dysfunction

  9. The conformity of a soft contact lens on the eye.

    Science.gov (United States)

    Funkenbusch, G M; Benson, R C

    1996-08-01

    An axisymmetric elastic shell deformation model has been created to predict the conformity of a soft contact lens when pressed against the eye. Regions of contact and gap may be predicted, and the nonuniform reaction pressure between the lens and eye may also be found. This is important for issues like abrasion and comfort. Bending, membrane and transverse shear loads within the lens are also computed. Commercial soft contact lenses and a representative eye shape are used for the examples. We find that the uniformity of loading against the eye is strongly affected by the degree to which the lens is shaped to fit the eye, and relatively unaffected by the thickness of the lens.

  10. Dielectric Optical-Controlled Magnifying Lens by Nonlinear Negative Refraction

    CERN Document Server

    Cao, Jianjun; Zheng, Yuanlin; Chen, Xianfeng; Liang, Xiaogan; Wan, Wenjie

    2014-01-01

    A simple optical lens plays an important role for exploring the microscopic world in science and technology by refracting light with tailored spatially varying refractive index. Recent advancements in nanotechnology enable novel lenses, such as, superlens, hyperlens, Luneburg lens, with sub-wavelength resolution capabilities by specially designing materials' refractive indices with meta-materials and transformation optics. However, these artificially nano/micro engineered lenses usually suffer high losses from metals and are highly demanding in fabrication. Here we experimentally demonstrate for the first time a nonlinear dielectric magnifying lens using negative refraction by degenerate four-wave mixing in a plano-concave glass slide, obtaining magnified images. Moreover, we transform a nonlinear flat lens into a magnifying lens by introducing transformation optics into nonlinear regime, achieving an all-optical controllable lensing effect through nonlinear wave mixing, which may have many potential applicat...

  11. Actively tunable plasmonic lens for subwavelength imaging at different wavelengths

    CERN Document Server

    Zeng, Beibei; Luo, Xiangang

    2011-01-01

    A type of tunable plasmonic lens with nanoslits is proposed for subwavelength imaging in the far field at different wavelengths. The nanoslits array in the plasmonic lens, which have constant depths but varying widths, could generate desired optical phase retardations based on the particular propagation property of the Surface Plasmon Polaritons (SPPs) in the metal-dielectric-metal (MDM) slit waveguides. We theoretically and numerically demonstrate the tunability of a single plasmonic lens for subwavelength imaging (full width at half maximum, 0.37 ~0.47) by adjusting the surrounding dielectric fluid, thereby realizing the compact in-plane tunable plasmonic lens. This work provides a novel approach for developing integrative tunable plasmonic lens for a variety of lab-on-chip applications.

  12. J0316+4328: a Probable "Asymmetric Double" Lens

    CERN Document Server

    Boyce, E R; Browne, I W A; Stroman, W J; Jackson, N J

    2007-01-01

    We report a probable gravitational lens J0316+4328, one of 19 candidate asymmetric double lenses (2 images at a high flux density ratio) from CLASS. Observations with the Very Large Array (VLA), MERLIN and the Very Long Baseline Array (VLBA) imply that J0316+4328 is a lens with high confidence. It has 2 images separated by 0.40", with 6 GHz flux densities of 62 mJy and 3.2 mJy. The flux density ratio of ~19 (constant over the frequency range 6-22 GHz) is the largest for any 2 image gravitational lens. High resolution optical imaging and deeper VLBI maps should confirm the lensing interpretation and provide inputs to detailed lens models. The unique configuration will give strong constraints on the lens galaxy's mass profile.

  13. Preliminary of Optical Lens Design for Micro-Satellite

    Science.gov (United States)

    Rachim, Elvira; Mukhtar Tahir, Andi; Herawan, Agus

    2017-01-01

    The development of micro satellites for the last two decades is emerging rapidly as the need of satellite communication usage is increasing. Earth observation is one of the example of how satellites are on demand. Most observation satellites consist of sensors and imaging system on-board. One of the key element to have a good imaging system is a special optical lens system design. Such lens is designed specifically by calculating every parameter such as refractive, reflective indexes, type of surface, distance and many more. Manufactured lenses sometimes do not match the requirement of an imager system hence the special lens design is needed. This paper will first briefly describe the history of optic, theory related to lens system, then the design and the analysis of lens system for micro-satellites generally and LAPAN A4 particularly.

  14. Antimicrobial compounds in tears.

    Science.gov (United States)

    McDermott, Alison M

    2013-12-01

    The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here.

  15. Aspherical mirrors for the Gamma-ray Cherenkov Telescope, a Schwarschild-Couder prototype proposed for the future Cherenkov Telescope Array

    Science.gov (United States)

    Dournaux, J. L.; Gironnet, J.; Huet, J. M.; Laporte, P.; Chadwick, P.; Dumas, D.; Pech, M.; Rulten, C. B.; Sayède, F.; Schmoll, J.; Sol, H.

    2016-07-01

    The Cherenkov Telescope Array (CTA) project, led by an international collaboration of institutes, aims to create the world's largest next generation Very High-Energy (VHE) gamma-ray telescope array, devoted to observations in a wide band of energy, from a few tens of GeV to more than 100 TeV. The Small-Sized Telescopes (SSTs) are dedicated to the highest energy range. Seventy SSTs are planned in the baseline array design with a required lifetime of about 30 years. The GCT (Gamma-ray Cherenkov Telescope) is one of the prototypes proposed for CTA's SST sub-array. It is based on a Schwarzschild-Couder dual-mirror optical design. This configuration has the benefit of increasing the field-of-view and decreasing the masses of the telescope and of the camera. But, in spite of these many advantages, it was never implemented before in ground-based Cherenkov astronomy because of the aspherical and highly curved shape required for the mirrors. The optical design of the GCT consists of a primary 4 meter diameter mirror, segmented in six aspherical petals, a secondary monolithic 2-meter mirror and a light camera. The reduced number of segments simplifies the alignment of the telescope but complicates the shape of the petals. This, combined with the strong curvature of the secondary mirror, strongly constrains the manufacturing process. The Observatoire de Paris implemented metallic lightweight mirrors for the primary and the secondary mirrors of GCT. This choice was made possible because of the relaxed requirements of optical Cherenkov telescopes compared to optical ones. Measurements on produced mirrors show that these ones can fulfill requirements in shape, PSF and reflectivity, with a clear competition between manufacturing cost and final performance. This paper describes the design of these mirrors in the context of their characteristics and how design optimization was used to produce a lightweight design. The manufacturing process used for the prototype and planned for the

  16. Cataract Surgery for Tilted Lens in Peters' Anomaly Type 2

    Directory of Open Access Journals (Sweden)

    Tadayuki Nishide

    2013-09-01

    Full Text Available Background: Cases of cataract surgery without penetrating keratoplasty in patients with Peters' anomaly are very rare. We report a case of Peters' anomaly type 2 with tilted lens due to synechia between the lens and iris that was treated with cataract surgery without penetrating keratoplasty. Case Presentation: A 16-year-old girl had Peters' anomaly in both eyes. Corneal opacity was severe in the left eye due to high-grade dysgenesis of the anterior segment. In the right eye, corneal opacity had spread from the center of the cornea to the inferotemporal side, and there was synechia between the iris and corneal endothelium from the inferonasal side to the inferotemporal side. Opacity was observed in the anterior pole of the lens, and there was synechia between the anterior iris and the lens. Ultrasound biomicroscopy (UBM revealed that the lens was tilted because of synechia. The tilted lens induced astigmatism, which reduced visual acuity to 20/250, in conjunction with a cataract. Cataract surgery was performed; the synechia between the lens capsule and the iris was severed, an intraocular lens was inserted, and the tilt was repaired. UBM was used postoperatively to confirm that the lens capsule synechia had been corrected and that the intraocular lens was not tilted. As a result, visual acuity improved to 20/100; glaucoma and expansion of corneal opacity were not observed. Conclusions: Severing of the synechia between the cataract and iris, during cataract surgery, in a patient with Peters' anomaly type 2 resulted in favorable postoperative visual acuity.

  17. Cosmic Lens Reveals Distant Galactic Violence

    Science.gov (United States)

    2008-10-01

    By cleverly unraveling the workings of a natural cosmic lens, astronomers have gained a rare glimpse of the violent assembly of a young galaxy in the early Universe. Their new picture suggests that the galaxy has collided with another, feeding a supermassive black hole and triggering a tremendous burst of star formation. Gravitational Lens Diagram Imaging a Distant Galaxy Using a Gravitational Lens CREDIT: Bill Saxton, NRAO/AUI/NSF Click on image for details and more graphics. The astronomers used the National Science Foundation's Very Large Array (VLA) radio telescope to look at a galaxy more than 12 billion light-years from Earth, seen as it was when the Universe was only about 15 percent of its current age. Between this galaxy and Earth lies another distant galaxy, so perfectly aligned along the line of sight that its gravity bends the light and radio waves from the farther object into a circle, or "Einstein Ring." This gravitational lens made it possible for the scientists to learn details of the young, distant galaxy that would have been unobtainable otherwise. "Nature provided us with a magnifying glass to peer into the workings of a nascent galaxy, providing an exciting look at the violent, messy process of building galaxies in the early history of the Universe," said Dominik Riechers, who led this project at the Max Planck Institute for Astronomy in Germany and now is a Hubble Fellow at the California Institute of Technology (Caltech). The new picture of the distant galaxy, dubbed PSS J2322+1944, shows a massive reservoir of gas, 16,000 light-years in diameter, that contains the raw material for building new stars. A supermassive black hole is voraciously eating material, and new stars are being born at the rate of nearly 700 Suns per year. By comparison, our Milky Way Galaxy produces the equivalent of about 3-4 Suns per year. The black hole appears to be near the edge, rather than at the center, of the giant gas reservoir, indicating, the astronomers say

  18. Bacterial transmission from lens storage cases to contact lenses - Effects of lens care solutions and silver impregnation of cases

    NARCIS (Netherlands)

    Vermeltfoort, Pit B. J.; Hooymans, Johanna M. M.; Busscher, Henk J.; van der Mei, Henny C.

    2008-01-01

    The killing efficacies of multipurpose lens care solutions on planktonic and biofilm bacteria grown in polypropylene contact lens storage cases with and without silver impregnation and effects on bacterial transmission from storage cases to silicone hydrogel contact lenses were investigated. For tra

  19. Force analysis of bacterial transmission from contact lens cases to corneas, with the contact lens as the intermediary

    NARCIS (Netherlands)

    Qu, Wen-wen; Hooymans, Johanna MM; de Vries, Jacob; van der Mei, Henderina; Busscher, Hendrik

    2011-01-01

    PURPOSE. To determine the probability of transmission of a Staphylococcus aureus strain from a contact lens case, to the contact lens (CL) surfaces, to the cornea, on the basis of bacterial adhesion forces measured by using atomic force microscopy (AFM). METHODS. Adhesion forces between S. aureus st

  20. The Sloan Lens ACS Survey. I. A large spectroscopically selected sample of massive early-type lens galaxies

    NARCIS (Netherlands)

    Bolton, AS; Burles, S; Koopmans, LVE; Treu, T; Moustakas, LA

    2006-01-01

    The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple

  1. Design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye

    Science.gov (United States)

    Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Iturbide-Jiménez, F.; Martínez-López, M.; Ramírez-Como, M.; Armengol-Cruz, V.; Vásquez-Báez, I.

    2014-09-01

    Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.; this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks®. We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO®.

  2. Time lens assisted photonic sampling extraction

    Science.gov (United States)

    Petrillo, Keith Gordon

    Telecommunication bandwidth demands have dramatically increased in recent years due to Internet based services like cloud computing and storage, large file sharing, and video streaming. Additionally, sensing systems such as wideband radar, magnetic imaging resonance systems, and complex modulation formats to handle large data transfer in telecommunications require high speed, high resolution analog-to-digital converters (ADCs) to interpret the data. Accurately processing and acquiring the information at next generation data rates from these systems has become challenging for electronic systems. The largest contributors to the electronic bottleneck are bandwidth and timing jitter which limit speed and reduce accuracy. Optical systems have shown to have at least three orders of magnitude increase in bandwidth capabilities and state of the art mode locked lasers have reduced timing jitters into thousands of attoseconds. Such features have encouraged processing signals without the use of electronics or using photonics to assist electronics. All optical signal processing has allowed the processing of telecommunication line rates up to 1.28 Tb/s and high resolution analog-to-digital converters in the 10s of gigahertz. The major drawback to these optical systems is the high cost of the components. The application of all optical processing techniques such as a time lens and chirped processing can greatly reduce bandwidth and cost requirements of optical serial to parallel converters and push photonically assisted ADCs into the 100s of gigahertz. In this dissertation, the building blocks to a high speed photonically assisted ADC are demonstrated, each providing benefits to its own respective application. A serial to parallel converter using a continuously operating time lens as an optical Fourier processor is demonstrated to fully convert a 160-Gb/s optical time division multiplexed signal to 16 10-Gb/s channels with error free operation. Using chirped processing, an

  3. TU-E-201-03: Eye Lens Dosimetry in Radiotherapy Using Contact Lens-Shaped Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. [Seoul National University Hospital (Korea, Republic of)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  4. TU-E-201-01: Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionists

    Energy Technology Data Exchange (ETDEWEB)

    Rehani, M. [Massachusetts General Hospital (United States)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  5. Perubahan Sosial Berbasis Tasawuf: Studi Kasus Fethullah Gülen Dan Gülen Movement

    Directory of Open Access Journals (Sweden)

    Sulaiman Sulaiman

    2016-06-01

    Full Text Available Abstract: This article aims at analyzing Fethullah Gülen and the Gülen Movement which have succeeded in performing social change based on the teaching of Sufism. He did Sufism creativity in order that Sufism teaching was able to respond the changes that occur in the modernlife. He believed that, only by reinterpretation and contextualization of Sufism, the spiritual dimension of Islam would be able to perform the transformation or social change among the Muslims. Therefore, by using Max Weber’s theory of social action, this paper will analyze three key teachings of Sufism of Gülen: ascetic (zuhd, inbisat (expansion, and hizmet. Based on the Weber's theory, Gülen occupied a very central and authoritative position: agent/actor, action and meaning. As a source of meaning and interpreter of meaning, the key concepts of Sufism were transformed by Gülen to the internal and external communities so that they had made a move to do social movements and humanity. For the followers of Gülen, the movement was called the Gülen Movement or the Hizmet Movement which was engaged in the fields of education, health care, humanitarian assistance, and the mass media. All forms of movement were entirely based on the spiritual values of Islam that had been formulated by Gülen. الملخص: يهدف هذا البحث إلى تحليل شخصية فتح الله غولن وحركته الذي تمكن من القيام بالتغيير الاجتماعي على أساس التعاليم الصوفية. إن فتح الله غولن قام بإحياء التصوف في صورته الجدّية والحيوية في حياة الإنسان المعاصر. ويعتقد أن إعادة التفسير لتعاليم التصوف مع مراعاة الواقع قادرة على التغيير الاجتماعي بين المسلمين. من أجل ذلك، أن استخدام نظرية ويبر، يمكن تحليل تعاليم التصوف الثلاثة

  6. CERN through the lens of Peter Ginter

    CERN Multimedia

    2008-01-01

    This summer, passers-by along the Quai Wilson on the banks of Lake Geneva will be able to enjoy an unusual exhibition of photographs devoted to CERN and the LHC. Fifty images from the work of Peter Ginter, organized into themes, give strollers on the Quai Wilson a glimpse of the unique human and scientific adventure at CERN. An exhibition panel, showing a scientist against the background of ALICE’s huge red electromagnet.CERN will reach an important milestone in 2008 with the start-up of the LHC, opening a new window on our Universe for physicists around the world. To celebrate this event with the people who live around Lake Geneva and visitors to the area, CERN and the city of Geneva are jointly putting on the photography exhibition "CERN through the lens of Peter Ginter", which opens on 29 May. A group of some fifty images taken by the German photo...

  7. Large scale water lens for solar concentration.

    Science.gov (United States)

    Mondol, A S; Vogel, B; Bastian, G

    2015-06-01

    Properties of large scale water lenses for solar concentration were investigated. These lenses were built from readily available materials, normal tap water and hyper-elastic linear low density polyethylene foil. Exposed to sunlight, the focal lengths and light intensities in the focal spot were measured and calculated. Their optical properties were modeled with a raytracing software based on the lens shape. We have achieved a good match of experimental and theoretical data by considering wavelength dependent concentration factor, absorption and focal length. The change in light concentration as a function of water volume was examined via the resulting load on the foil and the corresponding change of shape. The latter was extracted from images and modeled by a finite element simulation.

  8. Hyperbolic metamaterial lens with hydrodynamic nonlocal response

    DEFF Research Database (Denmark)

    Yan, Wei; Mortensen, N. Asger; Wubs, Martijn

    2013-01-01

    in the local-response approximation and in the hydrodynamic Drude model can differ considerably. In particular, the optimal frequency for imaging in the nonlocal theory is blueshifted with respect to that in the local theory. Thus, to detect whether nonlocal response is at work in a hyperbolic metamaterial, we......We investigate the effects of hydrodynamic nonlocal response in hyperbolic metamaterials (HMMs), focusing on the experimentally realizable parameter regime where unit cells are much smaller than an optical wavelength but much larger than the wavelengths of the longitudinal pressure waves...... of the free-electron plasma in the metal constituents. We derive the nonlocal corrections to the effective material parameters analytically, and illustrate the noticeable nonlocal effects on the dispersion curves numerically. As an application, we find that the focusing characteristics of a HMM lens...

  9. Achromatic Metasurface Lens at Telecommunication Wavelengths.

    Science.gov (United States)

    Khorasaninejad, Mohammadreza; Aieta, Francesco; Kanhaiya, Pritpal; Kats, Mikhail A; Genevet, Patrice; Rousso, David; Capasso, Federico

    2015-08-12

    Nanoscale optical resonators enable a new class of flat optical components called metasurfaces. This approach has been used to demonstrate functionalities such as focusing free of monochromatic aberrations (i.e., spherical and coma), anomalous reflection, and large circular dichroism. Recently, dielectric metasurfaces that compensate the phase dispersion responsible for chromatic aberrations have been demonstrated. Here, we utilize an aperiodic array of coupled dielectric nanoresonators to demonstrate a multiwavelength achromatic lens. The focal length remains unchanged for three wavelengths in the near-infrared region (1300, 1550, and 1800 nm). Experimental results are in agreement with full-wave simulations. Our findings are an essential step toward a realization of broadband flat optical elements.

  10. Intraocular lens employed for cataract surgery

    Science.gov (United States)

    Roszkowska, A. M.; Torrisi, L.

    2014-04-01

    The aim of this paper is to illustrate the techniques of cataract surgery with implantation of intraocular lenses and some physical properties of the used materials. The new technology, coupled with extensive experience and the studied cases, permits to increase the standardization and accuracy of the engravings, by reducing the use and handling of surgical instruments inside the eye. At present it is possible to replace the cataract with crystalline lenses based on biopolymers such as PMMA, silicone, acrylic hydrophilic and hydrophobic acrylic. These materials are increasingly able to replace the natural lens and to ensure the fully functional of the eye. The role of femtosecond lasers in cataract surgery, to assist or replace several aspects of the manual cataract surgery, are discussed.

  11. Photochromic lens mirror-coated with Cr

    Science.gov (United States)

    Shin, Sungho; Lee, Myeongkyu

    2007-11-01

    We have designed and fabricated mirror-coated photochromic lenses for use in sunglasses. These lenses consisted of a Cr thin film sandwiched between two SiO2 layers on the front surface and an anti-reflection (AR) coating on the backside. The SiO2 films above and below the Cr layer were introduced as the protection and buffer layers, respectively. The AR coating was to suppress back-reflection from the lens surface. Deposition of all coating layers were carried out by an e-beam evaporator under Ar atmosphere at P = 10-5 Torr and T = 70 °C. As expected, the overall transmittance decreased with increasing Cr thickness. For a Cr layer of 5 nm thickness, it changed from about 45% in the bleached state down to 25% after exposure to sunlight. This is consistent with the transmission range typically required for sunglasses.

  12. Adding a lens Improves spinning speed characterization.

    Science.gov (United States)

    Mihaliuk, Eugene; Gullion, Terry

    2015-11-01

    Highly stable sample rotation is important in many solid-state NMR experiments. Whether the necessary stability is achieved is not always clear. Typically only an average frequency over some time interval (often relatively long and unknown) is available from the spinning speed controller readout, which is not representative of the short-term variations of instantaneous rotation frequency. The necessity of the relatively slow measurement of spinning speed is a consequence of phase noise in the tachometer, which prevents speed measurement to be both rapid and precise at the same time. We show that adding a lens to the tachometer, without any other changes in the probe, reduces phase noise by nearly an order of magnitude and allows improved measurement of the spinning speed.

  13. Gravitational Lens Recovery with GLASS: Measuring the mass profile and shape of a lens

    CERN Document Server

    Coles, Jonathan P; Saha, Prasenjit

    2014-01-01

    We use a new non-parametric gravitational modelling tool -- GLASS -- to determine what quality of data (strong lensing, stellar kinematics, and/or stellar masses) are required to measure the circularly averaged mass profile of a lens and its shape. GLASS uses an under-constrained adaptive grid of mass pixels to model the lens, searching through thousands of models to marginalise over model uncertainties. Our key findings are as follows: (i) for pure lens data, multiple sources with wide redshift separation give the strongest constraints as this breaks the well-known mass-sheet or steepness degeneracy; (ii) a single quad with time delays also performs well, giving a good recovery of both the mass profile and its shape; (iii) stellar masses -- for lenses where the stars dominate the central potential -- can also break the steepness degeneracy, giving a recovery for doubles almost as good as having a quad with time delay data, or multiple source redshifts; (iv) stellar kinematics provide a robust measure of the ...

  14. Spectral analysis and comparison of mineral deposits forming in opacified intraocular lens and senile cataractous lens

    Science.gov (United States)

    Lin, Shan-Yang; Chen, Ko-Hwa; Lin, Chih-Cheng; Cheng, Wen-Ting; Li, Mei-Jane

    2010-10-01

    This preliminary report was attempted to compare the chemical components of mineral deposits on the surfaces of an opacified intraocular lens (IOL) and a calcified senile cataractous lens (SCL) by vibrational spectral diagnosis. An opacified intraocular lens (IOL) was obtained from a 65-year-old male patient who had a significant decrease in visual acuity 2-years after an ocular IOL implantation. Another SCL with grayish white calcified plaque on the subcapsular cortex was isolated from a 79-year-old male patient with complicated cataract after cataract surgery. Optical light microscope was used to observe both samples and gross pictures were taken. Fourier transform infrared (FT-IR) and Raman microspectroscopic techniques were employed to analyze the calcified deposits. The curve-fitting algorithm using the Gaussian function was also used to quantitatively estimate the chemical components in each deposit. The preliminary results of spectral diagnosis indicate that the opacified IOL mainly consisted of the poorly crystalline, immature non-stoichiometric hydroxyapatite (HA) with higher content of type B carbonated apatites. However, the calcified plaque deposited on the SCL was comprised of a mature crystalline stoichiometric HA having higher contents of type A and type B carbonate apatites. More case studies should be examined in future.

  15. Solar lens mission concept for interstellar exploration

    Science.gov (United States)

    Brashears, Travis; Lubin, Philip; Turyshev, Slava; Shao, Michael; Zhang, Qicheng

    2015-09-01

    The long standing approach to space travel has been to incorporate massive on-board electronics, probes and propellants to achieve space exploration. This approach has led to many great achievements in science, but will never help to explore the interstellar medium. Fortunately, a paradigm shift is upon us in how a spacecraft is constructed and propelled. This paper describes a mission concept to get to our Sun's Gravity Lens at 550AU in less than 10 years. It will be done by using DE-STAR, a scalable solar-powered phased-array laser in Earth Orbit, as a directed energy photon drive of low-mass wafersats. [1] [2] [3] [4] [5] With recent technologies a complete mission can be placed on a wafer including, power from an embedded radio nuclear thermal generator (RTG), PV, laser communications, imaging, photon thrusters for attitude control and other sensors. As one example, a futuristic 200 MW laser array consisting of 1 - 10 kw meter scale sub elements with a 100m baseline can propel a 10 gram wafer scale spacecraft with a 3m laser sail to 60AU/Year. Directed energy propulsion of low-mass spacecraft gives us an opportunity to capture images of Alpha Centauri and its planets, detailed imaging of the cosmic microwave background, set up interstellar communications by using gravity lenses around nearby stars to boost signals from interstellar probes, and much more. This system offers a very large range of missions allowing hundreds of wafer scale payload launches per day to reach this cosmological data reservoir. Directed Energy Propulsion is the only current technology that can provide a near-term path to utilize our Sun's Gravity Lens.

  16. Magnesium compounds

    Science.gov (United States)

    Kramer, D.A.

    2012-01-01

    Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.

  17. A method based on diffraction theory for predicting 3D focusing performance of compound refractive X-ray lenses

    Institute of Scientific and Technical Information of China (English)

    Zichun Le; Kai Liu; Jingqiu Liang

    2005-01-01

    A method based on the diffraction theory for estimating the three-dimensional (3D) focusing performance of the compound refractive X-ray lenses is presented in this paper. As a special application, the 3D X-ray intensity distribution near the focus is derived for a plano-concave compound refractive X-ray lens.Moreover, the computer codes are developed and some results of 3D focusing performance for a compound refractive X-ray lens with Si material are shown and discussed.

  18. Thermal optical path difference analysis of off-axis lens ray trace foot-print at Cassegrain telescope correct lens assembly

    Science.gov (United States)

    Hsu, Ming-Ying; Lin, Yu-Chuan; Chan, Chia-Yen; Lin, Wei-Cheng; Chan, Shenq-Tsong; Huang, Ting-Ming

    2012-10-01

    The Cassegrain telescope system in this study, is discussion correct lens thermal OPD (Optical Path Difference) effect optical performance. The correct lens assembly are includes several components such as correct lens, lens mount, spacer, mount barrel and retainer. The heat transfer from surrounding to the correct lens barrel will causes optical system aberration. Meanwhile, the off-axis rays path of the OPD must consider lens incidence point and emergence point. The correct lens temperature distribution is calculate the lens barrel heat transfer analysis, the thermal distortion and stress are solve by FEM (Finite Element Method) software. The temperature calculation results can be weighting to each incidence ray path and calculate thermal OPD. The thermal OPD on Z-direction can be fitted by rigid body motion and Zernike polynomial. The fitting results can be used to evaluate the thermal effect on correct lens assembly in telescope system.

  19. Fabrication of Light Extraction Efficiency of Organic Light-Emitting Diodes with 3D Aspherical Microlens by Using Dry Etching Process

    Directory of Open Access Journals (Sweden)

    Y. C. Chen

    2013-01-01

    Full Text Available organic light-emitting diode (OLED can enable a greater artificial contrast ratio and viewing angle compared to liquid crystal display (LCD because OLED pixels directly emit light. There is a shortcoming that the internal quantum efficiency can reach values close to 100%, but about 80% light disperses because of the difference among the refractive indices of the substrate, anode, indium tin oxide (ITO film, and air. In this paper, three dimensions aspherical microlens arrays (3D A-MLAs with substrate modifications are developed to simulate the optical luminous field by using FRED software. This study modified parameters of 3D A-MLAs such as the diameter, fill-factor, aspect ratio, dry etching parameters, and electroforming rates of microlens to improve the extraction efficiency of the OLED. In dry etching, not only the aspect ratio with better extraction rate can be obtained by reactive ion etching (RIE dry etching, but also an undercutting phenomenon can be avoided. The dimensions of 3D A-MLAs can be accurately controlled in the electroforming process used to make a nickel-cobalt (Ni-Co metal mold to achieve the designed dimensions. According to the measured results, the average luminance efficacy of the OLEDs with 3D A-MLAs can be enhanced.

  20. Explosive nucleosynthesis in the neutrino-driven aspherical supernova explosion of a non-rotating 15$M_{\\odot}$ star with solar metallicity

    CERN Document Server

    Fujimoto, Shin-ichiro; Hashimoto, Masa-aki; Ono, Masaomi; Ohnishi, Naofumi

    2011-01-01

    We investigate explosive nucleosynthesis in a non-rotating 15$M_\\odot$ star with solar metallicity that explodes by a neutrino-heating supernova (SN) mechanism aided by both standing accretion shock instability (SASI) and convection. To trigger explosions in our two-dimensional hydrodynamic simulations, we approximate the neutrino transport with a simple light-bulb scheme and systematically change the neutrino fluxes emitted from the protoneutron star. By a post-processing calculation, we evaluate abundances and masses of the SN ejecta for nuclei with the mass number $\\le 70$ employing a large nuclear reaction network. Aspherical abundance distributions, which are observed in nearby core-collapse SN remnants, are obtained for the non-rotating spherically-symmetric progenitor, due to the growth of low-mode SASI. Abundance pattern of the supernova ejecta is similar to that of the solar system for models whose masses ranges $(0.4-0.5) \\Ms$ of the ejecta from the inner region ($\\le 10,000\\km$) of the precollapse ...

  1. Flavin nucleotides in human lens: regional distribution in brunescent cataracts.

    Science.gov (United States)

    Bhat, K S; Nayak, S

    1998-12-01

    The biochemical mechanism(s) underlying brunescent cataracts remain unclear. Oxidative stress due to reactive oxygen species may have a role in the pigmentation process in eye lens. We have analysed human cataractous lenses for flavins by high-performance liquid chromatography (HPLC), since flavins are light sensitive and act as endogenous sensitizers generating reactive oxygen species in the eye. The most significant observation in this study is that higher levels of flavin nucleotides occur in brown lens compared to yellow lens. The concentration of flavin nucleotides (flavin monouncleotide, FMN + flavin adenine dinucleotide, FAD) was highest in the nuclear region of the lens followed by the cortical and capsule-epithelial regions. However, the ratio of FAD/FMN was lowest in the nuclear region of the lens followed by other regions. On the other hand, riboflavin was not detected in any of the lens (cataractous) regions. These results suggest that the observed increase in flavin nucleotides in the ocular tissue could contribute towards deepening of lens pigmentation.

  2. Fgf19 is required for zebrafish lens and retina development.

    Science.gov (United States)

    Nakayama, Yoshiaki; Miyake, Ayumi; Nakagawa, Yu; Mido, Tomotaka; Yoshikawa, Maya; Konishi, Morichika; Itoh, Nobuyuki

    2008-01-15

    Fgf signaling plays crucial roles in morphogenesis. Fgf19 is required for zebrafish forebrain development. Here, we examined the roles of Fgf19 in the formation of the lens and retina in zebrafish. Knockdown of Fgf19 caused a size reduction of the lens and the retina, failure of closure of the choroids fissure, and a progressive expansion of the retinal tissue to the midline of the forebrain. Fgf19 expressed in the nasal retina and lens was involved in cell survival but not cell proliferation during embryonic lens and retina development. Fgf19 was essential for the differentiation of lens fiber cells in the lens but not for the neuronal differentiation and lamination in the retina. Loss of nasal fate in the retina caused by the knockdown of Fgf19, expansion of nasal fate in the retina caused by the overexpression of Fgf19 and eye transplantation indicated that Fgf19 in the retina was crucial for the nasal-temporal patterning of the retina that is critical for the guidance of retinal ganglion cell axons. Knockdown of Fgf19 also caused incorrect axon pathfinding. The present findings indicate that Fgf19 positively regulates the patterning and growth of the retina, and the differentiation and growth of the lens in zebrafish.

  3. MALDI-MS-imaging of whole human lens capsule.

    Science.gov (United States)

    Ronci, Maurizio; Sharma, Shiwani; Chataway, Tim; Burdon, Kathryn P; Martin, Sarah; Craig, Jamie E; Voelcker, Nicolas H

    2011-08-05

    The ocular lens capsule is a smooth, transparent basement membrane that encapsulates the lens and is composed of a rigid network of interacting structural proteins and glycosaminoglycans. During cataract surgery, the anterior lens capsule is routinely removed in the form of a circular disk. We considered that the excised capsule could be easily prepared for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry imaging (MALDI-MSI) analysis. MALDI-MSI is a powerful tool to elucidate the spatial distribution of small molecules, peptides, and proteins within tissues. Here, we apply this molecular imaging technique to analyze the freshly excised human lens capsule en face. We demonstrate that novel information about the distribution of proteins by MALDI-MSI can be obtained from this highly compact connective tissue, having no evident histo-morphological characteristics. Trypsin digestion carried out on-tissue is shown to improve MALDI-MSI analysis of human lens capsules and affords high repeatability. Most importantly, MALDI-MSI analysis reveals a concentric distribution pattern of proteins such as apolipoprotein E (ApoE) and collagen IV alpha-1 on the anterior surface of surgically removed lens capsule, which may indicate direct or indirect effects of environmental and mechanical stresses on the human ocular lens.

  4. Numerical implementation of generalized Coddington equations for ophthalmic lens design

    Science.gov (United States)

    Rojo, P.; Royo, S.; Ramírez, J.; Madariaga, I.

    2014-02-01

    A method for general implementation in any software platform of the generalized Coddington equations is presented, developed, and validated within a Matlab environment. The ophthalmic lens design strategy is presented thoroughly, and the basic concepts of generalized ray tracing are introduced. The methodology for ray tracing is shown to include two inter-related processes. Firstly, finite ray tracing is used to provide the main direction of propagation of the considered ray at the incidence point of interest. Afterwards, generalized ray tracing provides the principal curvatures of the local wavefront at that point, and its orientation after being refracted by the lens. The curvature values of the local wavefront are interpreted as the sagital and tangential powers of the lens at the point of interest. The proposed approach is validated using a double-check of the calculated lens performance in the spherical lens case: while finite ray tracing is validated using a commercial ray tracing software, generalized ray tracing is validated using a software application for ophthalmic lens design based on the classical version of Coddington equations. Equations of the complete tracing process are developed in detail for the case of generic astigmatic ophthalmic lenses as an example. Three-dimensional representation of the sagital and tangential powers of the ophthalmic lens at all directions of gaze then becomes possible, and results are presented for lenses with different geometries.

  5. c-Myc regulates cell proliferation during lens development.

    Directory of Open Access Journals (Sweden)

    Gabriel R Cavalheiro

    Full Text Available Myc protooncogenes play important roles in the regulation of cell proliferation, growth, differentiation and survival during development. In various developing organs, c-myc has been shown to control the expression of cell cycle regulators and its misregulated expression is detected in many human tumors. Here, we show that c-myc gene (Myc is highly expressed in developing mouse lens. Targeted deletion of c-myc gene from head surface ectoderm dramatically impaired ocular organogenesis, resulting in severe microphtalmia, defective anterior segment development, formation of a lens stalk and/or aphakia. In particular, lenses lacking c-myc presented thinner epithelial cell layer and growth impairment that was detectable soon after its inactivation. Defective development of c-myc-null lens was not caused by increased cell death of lens progenitor cells. Instead, c-myc loss reduced cell proliferation, what was associated with an ectopic expression of Prox1 and p27(Kip1 proteins within epithelial cells. Interestingly, a sharp decrease in the expression of the forkhead box transcription factor Foxe3 was also observed following c-myc inactivation. These data represent the first description of the physiological roles played by a Myc family member in mouse lens development. Our findings support the conclusion that c-myc regulates the proliferation of lens epithelial cells in vivo and may, directly or indirectly, modulate the expression of classical cell cycle regulators in developing mouse lens.

  6. Test results of high-precision large cryogenic lens holders

    Science.gov (United States)

    Gal, C.; Reutlinger, A.; Boesz, A.; Leberle, T.; Mottaghibonab, A.; Eckert, P.; Dubowy, M.; Gebler, H.; Grupp, F.; Geis, N.; Bode, A.; Katterloher, R.; Bender, R.

    2012-09-01

    For the Euclid mission a Pre-Development phase is implemented to prove feasibility of individual components of the system [1]. The Near Infrared Spectrometer and Photometer (NISP) of EUCLID requires high precision large lens holders (?170 mm) at cryogenic temperatures (150K). The four lenses of the optical system are made of different materials: fused silica, CaF2, and LF5G15 that are mounted in a separate lens barrel design. Each lens has its separate mechanical interface to the lens barrel, the so called adaption ring. The performance of the lens holder design is verified by adapted test equipment and test facility including an optical metrology system. The characterization of the lens deformation and displacement (decenter, tilt) due to mechanical loads of the holder itself as well as thermally induced loads are driven by the required submicron precision range and the operational thermal condition. The surface deformation of the lens and its holder is verified by interferometric measurements, while tilt and position accuracy are measured by in-situ fibre based distance sensors. The selected distance measurement sensors have the capability to measure in a few mm range with submicron resolution in ultra high vacuum, in vibration environments and at liquid nitrogen temperatures and below. The calibration of the measurement system is of crucial importance: impacts such as temperature fluctuation, surface roughness, surface reflectivity, straylight effects, etc. on the measured distance are carefully calibrated. Inbuilt thermal expansion effects of the fibre sensors are characterized and proven with lens dummy with quasi zero CTE. The paper presents the test results and measured performance of the high precision large cryogenic lens holders attained by the metrology system. These results are presented on behalf of the EUCLID consortium.

  7. Critical Assessment of Correction Methods for Fisheye Lens Distortion

    Science.gov (United States)

    Liu, Y.; Tian, C.; Huang, Y.

    2016-06-01

    A fisheye lens is widely used to create a wide panoramic or hemispherical image. It is an ultra wide-angle lens that produces strong visual distortion. The distortion modeling and estimation of the fisheye lens are the crucial step for fisheye lens calibration and image rectification in computer vision and close-range photography. There are two kinds of distortion: radial and tangential distortion. Radial distortion is large for fisheye imaging and critical for the subsequent image processing. Although many researchers have developed calibration algorithms of radial distortion of fisheye lens, quantitative evaluation of the correction performance has remained a challenge. This is the first paper that intuitively and objectively evaluates the performance of five different calibration algorithms. Upto- date research on fisheye lens calibration is comprehensively reviewed to identify the research need. To differentiate their performance in terms of precision and ease-using, five methods are then tested using a diverse set of actual images of the checkerboard that are taken at Wuhan University, China under varying lighting conditions, shadows, and shooting angles. The method of rational function model, which was generally used for wide-angle lens correction, outperforms the other methods. However, the one parameter division model is easy for practical use without compromising too much the precision. The reason is that it depends on the linear structure in the image and requires no preceding calibration. It is a tradeoff between correction precision and ease-using. By critically assessing the strengths and limitations of the existing algorithms, the paper provides valuable insight and guideline for future practice and algorithm development that are important for fisheye lens calibration. It is promising for the optimal design of lens correction models that are suitable for the millions of portable imaging devices.

  8. Effects of x-irradiation on lens reducing systems. [Rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Giblin, F.J.; Chakrapani, B.; Reddy, V.N.

    1978-01-01

    Studies have been made of the effects of x ray on various lens reducing systems including the levels of NADPH and glutathione (GSH), the activity of the hexose monophosphate shunt (HMS), and the activities of certain enzymes including glutathion reductase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase (G-6-PD). It was found that during several weeks following x irradiation but prior to cataract formation there was very little change in the number of reduced -SH groups per unit weight of lens protein but that, with the appearance of cataract, there was a sudden loss of protein -SH groups. In contrast, the concentration of GSH in the x-rayed lens decreased throughout the experimental period. Similarly, the concentration of NADPH in the x-rayed lens was found to decrease significantly relative to controls one week prior to cataract formation and the ratio of NADPH to NADP/sup +/ in the lens shifted at this time period from a value greater than 1.0 in the control lens to less than 1.0 in the x-rayed lens. A corresponding decrease occurred in the activity of the HMS in x-rayed lenses as measured by culture in the presence of 1-/sup 14/C-labelled glucose. G-6-PD was partially inactivated in the x-rayed lens. Of the eight enzymes studied, G-6-PD appeared to be the most sensitive to x-irradiation. The data indicate that x-irradiation results in a steady decrease in the effectiveness of lens reducing systems and that, when these systems reach a critically low point, sudden oxidation of protein -SH groups and formation of high molecular weight protein aggregates may be initiated.

  9. Evolutionary algorithm for optimization of nonimaging Fresnel lens geometry.

    Science.gov (United States)

    Yamada, N; Nishikawa, T

    2010-06-21

    In this study, an evolutionary algorithm (EA), which consists of genetic and immune algorithms, is introduced to design the optical geometry of a nonimaging Fresnel lens; this lens generates the uniform flux concentration required for a photovoltaic cell. Herein, a design procedure that incorporates a ray-tracing technique in the EA is described, and the validity of the design is demonstrated. The results show that the EA automatically generated a unique geometry of the Fresnel lens; the use of this geometry resulted in better uniform flux concentration with high optical efficiency.

  10. Comparison of shape recovery ratios in various intraocular lens haptics.

    Science.gov (United States)

    Kimura, W; Kimura, T; Sawada, T; Kikuchi, T; Toda, H; Yamada, Y; Nagai, H

    1992-11-01

    Since understanding the mechanical properties of intraocular lens (IOL) haptic materials can minimize decentration after surgery, we have examined shape recovery ratios of various intraocular lens haptics (polypropylene [PP], polyvinylidene fluoride [PVDF], extruded poly(methyl methacrylate) [PMMA]) currently on the market under conditions that approximate clinical use. The results using various Ascon lens-holding forceps and compression tests, during which the lenses were held in a cylindrical holder for seven days, one month, and three months, indicated that PVDF haptics had better shape recovery capability than PP and extruded three-piece PMMA haptics.

  11. Research of the long-focus Maksutov telephoto lens

    Science.gov (United States)

    Tarasov, I. P.; Tsyganok, E. A.

    2016-04-01

    The article presents the research result and the optical design of long-focus telephoto lens for photo shooting by the academician Maksutov's scheme. It shows a review of lenses for photo shooting on the market today, and also an analysis of the correctional possibilities which is based on the scheme is presented; studied long-focus telephoto lens is compared with its closest analog, the calculation of a new telephoto lens with higher image quality is made on the basis of that comparison.

  12. Characteristic of laser diode beam propagation through a collimating lens.

    Science.gov (United States)

    Xu, Qiang; Han, Yiping; Cui, Zhiwei

    2010-01-20

    A mathematical model of a laser diode beam propagating through a collimating lens is presented. Wave propagation beyond the paraxial approximation is studied. The phase delay of the laser diode wave in passing through the lens is analyzed in detail. The propagation optical field after the lens is obtained from the diffraction integral by the stationary phase method. The model is employed to predict the light intensity at various beam cross sections, and the computed intensity distributions are in a good agreement with the corresponding measurements.

  13. Development of a universal toric intraocular lens calculator

    Science.gov (United States)

    Hjelmstad, David; Sayegh, Samir I.

    2014-02-01

    We present a method for calculating the ideal toric lens to implant in astigmatic patients following cataract surgery. We show that the online calculators provided by major toric IOL manufacturers are insufficient for both theoretical and practical reasons. We reveal important theoretical shortcomings in their approach, illustrated by a number of cases which demonstrate how the approach can lead to errors in lens selection. Our approach combines the spherical and cylindrical power calculations into one, and allows for lens data from any manufacturer to be used, eliminating the reliance on multiple programs.

  14. Vortexlike Power Flow at the Interfaces of Metamaterial Lens

    Directory of Open Access Journals (Sweden)

    K. Fang

    2012-10-01

    Full Text Available The metamaterial lens with DPS/DNS/DPS structure has been realized by using the two-dimensional (2D isotropic transmission line approach. We studied the vortexlike power flow at the interfaces of metamaterial lens and validated by the finite-difference time-domain (FDTD simulator. The computational results showing its different conditions near DPS/DNS and other kinds of interfaces are obtained by CST STUDIO SUITE at different frequencies, and demonstrate the intuitionistic power location at the metamaterial lens interfaces.

  15. Means to flexibly attach lens frames to temple members

    Science.gov (United States)

    Smith, Harry D.

    1995-01-01

    The invention is a band hinge for flexibly connecting the temple member to the lens frame thereby preventing damage from inadvertent pressure or cyclic wear. A distinguishing feature of the invention is the use of a band hinge that holds together the temple member and the lens frame without the use of a pin or screw hinging mechanism. The invention allows for a high degree of freedom of movement for the temple member with respect to the lens frame which will prevent most forms of damages to the glasses from these types of events.

  16. 21 CFR 886.5918 - Rigid gas permeable contact lens care products.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rigid gas permeable contact lens care products... contact lens care products. (a) Identification. A rigid gas permeable contact lens care product is a... rigid gas permeable contact lens. This includes all solutions and tablets used together with rigid...

  17. Outcomes of Lensectomy in Hereditary Lens Subluxation

    Directory of Open Access Journals (Sweden)

    Mohammad-Hossein Dehghan

    2008-12-01

    Full Text Available

    PURPOSE: To evaluate the results of pars plana lensectomy in patients with hereditary lens subluxation. METHOD: Hospital records of patients with hereditary lens subluxation who had undergone pars plana lensectomy at Labbafinejad Medical Center, Tehran-Iran from 1996 to 2003 were reviewed. Patients with more than 6 months of follow up were included. Underlying disorders, best corrected visual acuity (BCVA before and after surgery, intraocular pressure (IOP, postoperative refraction and complications were evaluated. RESULTS: Overall, records of 87 eyes of 49 patients including 27 male and 22 female subjects were reviewed. Mean follow up duration was 20±18 months. Underlying disorders leading to lens subluxation included Marfan syndrome (79.5%, Weill-Marchesani syndrome (8.2%, simple ectopia lentis (8.2%, and homocystinuria (4.1%. The most common indication for surgery was non-correctable refractive error (92.1%. Mean BCVA was 1.13 LogMAR (20/250 preoperatively, which improved to 0.26 LogMAR (20/30-20/40 postoperatively (P < 0.001. BCVA better than 20/40 was achieved in 82.8% of cases after surgery. Angle-supported anterior chamber intraocular lens (ACIOL was implanted in

  18. Patient comfort following thirty minutes of lens wear: piggy-back versus conventional rigid-lens wear

    OpenAIRE

    W.D.H. Gillan

    2014-01-01

    Discomfort when wearing contact lenses, especially rigid contact lenses, is a common complaint amongst neophyte as well as experienced contact lens wearers. Wearing a piggy-back system of contact lenses has been shown to improve comfort and wearing time, especially in keratoconic subjects. Twenty two normal subjects wore a rigid lens or a piggy-back system of lenses for thirty minutes and after a thirty minute break swopped the mode of lens wear and wore the second modality for a thirty minut...

  19. Degeneracies of parametric lens model families near folds and cusps

    CERN Document Server

    Wagner, Jenny

    2015-01-01

    We develop an approach to select families of lens models that can describe doubly and triply gravitationally lensed images near folds and cusps using the model-independent ratios of lensing-potential derivatives derived in Wagner & Bartelmann (2015). Models are selected by comparing these model-independent ratios of potential derivatives to (numerically determined) ratios of potential derivatives along critical curves for entire lens model families in a given range of parameter values. This comparison returns parameter ranges which lens model families can reproduce observation within, as well as sections of the critical curve where image sets of the observed type can appear. If the model-independent potential-derivative ratios inferred from the observation fall outside the range of these ratios derived for the lens model family, the entire family can be excluded as a feasible model in the given volume in parameter space. We employ this approach for the family of singular isothermal spheres with external s...

  20. Applications of thermal lens spectrometry in food industry and agriculture.

    NARCIS (Netherlands)

    Franko, M.; Bicanic, D.; Gibkes, J.; Bremer, M.; Akkermans, E.

    1996-01-01

    Applications of CO laser dual beam thermal lens spectrometry (TLS) for detection and characterization of fatty acids, aldehydes, pesticides, and herbicides in liquid samples are described. Also reported is the first TLS measurement of thermal conductivity for oleic acid.

  1. Constraints on cosmological models from lens redshift data

    CERN Document Server

    Cao, Shuo

    2011-01-01

    Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structures, formations, and evolutions). Now several hundreds of strong lens systems produced by massive galaxies have been discovered, which may form well-defined samples useful for statistical analyses. To collect a relatively complete lens redshift data from various large systematic surveys of gravitationally lensed quasars and check the possibility to use it as a future complementarity to other cosmological probes. We use the distribution of gravitationally-lensed image separations observed in the Cosmic Lens All-Sky Survey (CLASS), the PMN-NVSS Extragalactic Lens Survey (PANELS), the Sloan Digital Sky Survey (SDSS) and other surveys, considering a singular isothermal ellipsoid (SIE) model for galactic potentials as well as improved new measurements of the velocity dispersion function of galaxies based on the SDSS DR5 data and recent semi-analytical modeling of galaxy formation, to constrain tw...

  2. Multiaxial mechanical behavior of the porcine anterior lens capsule.

    Science.gov (United States)

    Heistand, M R; Pedrigi, R M; Delange, S L; Dziezyc, J; Humphrey, J D

    2005-11-01

    The biomechanics of the lens capsule of the eye is important both in physiologic processes such as accommodation and clinical treatments such as cataract surgery. Although the lens capsule experiences multiaxial stresses in vivo, there have been no measurements of its multiaxial properties or possible regional heterogeneities. Rather all prior mechanical data have come from 1-D pressure-volume or uniaxial force-length tests. Here, we report a new experimental approach to study in situ the regional, multiaxial mechanical behavior of the lens capsule. Moreover, we report multiaxial data suggesting that the porcine anterior lens capsule exhibits a typical nonlinear pseudo-elastic behavior over finite strains, that the in situ state is pre-stressed multi-axially, and that the meridional and circumferential directions are principal directions of strain, which is nearly equi-biaxial at the pole but less so towards the equator. Such data are fundamental to much needed constitutive formulations.

  3. Regional multiaxial mechanical properties of the porcine anterior lens capsule.

    Science.gov (United States)

    David, G; Pedrigi, R M; Heistand, M R; Humphrey, J D

    2007-02-01

    The lens capsule of the eye plays fundamental biomechanical roles in both normal physiological processes and clinical interventions. There has been modest attention given to the mechanical properties of this important membrane, however, and prior studies have focused on 1-D analyses of the data. We present results that suggest that the porcine anterior lens capsule has a complex, regionally dependent, nonlinear, anisotropic behavior. Specifically, using a subdomain inverse finite element method to analyze data collected via a new biplane video-based test system, we found that the lens capsule is nearly isotropic (in-plane) near the pole but progressively stiffer in the circumferential compared to the meridional direction as one approaches the equator. Because the porcine capsule is a good model of the young human capsule, there is strong motivation to determine if similar regional variations exist in the human lens capsule for knowledge of such complexities may allow us to improve the design of surgical procedures and implants.

  4. 600 Volt Stretched Lens Array for Solar Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past six years, ENTECH, Auburn, NASA, and other organizations have developed a new space photovoltaic array called the Stretched Lens Array (SLA), which...

  5. An Atomic Lens Using a Focusing Hollow Beam

    Institute of Scientific and Technical Information of China (English)

    夏勇; 印建平; 王育竹

    2003-01-01

    We propose a new method to generate a focused hollow laser beam by using an azimuthally distributed 2π-phase plate and a convergent thin lens, and calculate the intensity distribution of the focused hollow beam in free propagation space. The relationship between the waist w0 of the incident collimated Gaussian beam and the dark spot size of the focused hollow beam at the focal point, and the relationship between the focal length f of the thin lens and the dark spot size are studied respectively. The optical potential of the blue-detuned focused hollow beam for 85Rb atoms is calculated. Our study shows that when the larger waist w of the incident Gaussian beam and the shorter focal length f of the lens are chosen, we can obtain an extremely small dark spot size of the focused hollow beam, which can be used to form an atomic lens with a resolution of several angstroms.

  6. Application of Foldable Intraocular Lens in Multiple Types of Cataract

    Institute of Scientific and Technical Information of China (English)

    Songtao Yuan; Qinghuai Liu; Qing Jiang; Nanrong Yuan

    2002-01-01

    Objective: To evaluate the clinical results of implantation of foldable intraocular lens inmultiple types of cataract.Methods: This retrospective study comprised 162 eyes of 148 patients undergoingphacoemulsification and implantation of foldable intraocular lens, some of whom under-went combined pars plana vitrectomy or trabeculectomy or silicone oil removal. Theperiod of follow-up was from 3 months to 17 months.Results: There is slight reaction postoperatively in all cases. The postoperative uncorrectedvisual acuites was from 0. 05 to 1.2, patient with 0.6 or above acuity were 70.98%. Aneodymium: YAG capsulotomy was required in 5 eyes. Posterior capsule ruptured in 1eyes, and a PMMA intraocular lens was implanted in ciliary sulcus. In one eye, a lenswas removed because of recurrence of retina detachment.Conclusions: The application of foldable intraocular lens in multiple types of cataract issafe, and there is a slight postoperative reaction. less complications , and fast visualacuity recovery.

  7. Tunable Focus Liquid Lens with Radial-Patterned Electrode

    Directory of Open Access Journals (Sweden)

    Miao Xu

    2015-08-01

    Full Text Available A dielectric liquid lens is prepared based on our previous work. By optimizing the device structure, the liquid lens presents a converging focus with good resolution and changes its focal length over a broad range with a low driving voltage. For a liquid lens with ~2.3 mm diameter in the relaxed state, it can resolve ~40 lp/mm. The resolution does not degrade during focus change. Its focal length can be varied from ~12 to ~5 mm when the applied voltage is changed from 0 to 28 Vrms. The response time of one cycle is ~2.5 s. Our liquid lens, with a low driving voltage for a large dynamic range, has potential applications in imaging, biometrics, optoelectronic, and lab-on-chip devices.

  8. A spiral plasmonic lens with directional excitation of surface plasmons.

    Science.gov (United States)

    Guo, Qingrui; Zhang, Chi; Hu, Xinhua

    2016-08-26

    Conventional plasmonic lenses are composed of curved slits carved through metallic films. Here, we propose a new plasmonic lens based on a metallic slit with an auxiliary groove. When the lens is illumined normally, only inward surface plasmon polaritons (SPPs) can be generated and then focused into a hot spot at the center of the lens. The focusing effect is theoretically investigated by varying the groove parameters and incident polarizations. It is found that this phenomenon exists for both the circular and linear polarizations of incidence. Under optimal groove parameters, the intensity of the focal spot in our lens can be 2.5 times of that in one without grooves for both linearly and circularly polarized illuminations.

  9. Flat acoustic lens by acoustic grating with curled slits

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Pai; Xiao, Bingmu; Wu, Ying, E-mail: ying.wu@kaust.edu.sa

    2014-10-03

    We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry–Perot resonance. - Highlights: • Expression of transmission coefficient of an acoustic grating with curled slits. • Non-dispersive and tunable effective medium parameters for the acoustic grating. • A flat acoustic focusing lens with gradient index by using the acoustic grating.

  10. A single-pixel wireless contact lens display

    Science.gov (United States)

    Lingley, A. R.; Ali, M.; Liao, Y.; Mirjalili, R.; Klonner, M.; Sopanen, M.; Suihkonen, S.; Shen, T.; Otis, B. P.; Lipsanen, H.; Parviz, B. A.

    2011-12-01

    We present the design, construction and in vivo rabbit testing of a wirelessly powered contact lens display. The display consists of an antenna, a 500 × 500 µm2 silicon power harvesting and radio integrated circuit, metal interconnects, insulation layers and a 750 × 750 µm2 transparent sapphire chip containing a custom-designed micro-light emitting diode with peak emission at 475 nm, all integrated onto a contact lens. The display can be powered wirelessly from ~1 m in free space and ~2 cm in vivo on a rabbit. The display was tested on live, anesthetized rabbits with no observed adverse effect. In order to extend display capabilities, design and fabrication of micro-Fresnel lenses on a contact lens are presented to move toward a multipixel display that can be worn in the form of a contact lens. Contact lenses with integrated micro-Fresnel lenses were also tested on live rabbits and showed no adverse effect.

  11. Negative time delay of light by a gravitational concave lens

    CERN Document Server

    Nakajima, Koki; Asada, Hideki

    2014-01-01

    Gravitational lens models, some of which might act as if a concave lens, have been recently investigated by using a static and spherically symmetric modified spacetime metric that depends on the inverse distance to the $n$-th power [Kitamura, Nakajima and Asada, PRD 87, 027501 (2013)]. We reexamine the time delay of light in a gravitational concave lens as well as a gravitational convex one. The frequency shift due to the time delay is also investigated. We show that the sign of the time delay in the lens models is the same as that of the deflection angle of light. The size of the time delay decreases with increase in the parameter $n$. We discuss also possible parameter ranges that are relevant to pulsar timing measurements in our galaxy.

  12. A 3D printed helical antenna with integrated lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2015-10-26

    A novel antenna configuration comprising a helical antenna with an integrated lens is demonstrated in this work. The antenna is manufactured by a unique combination of 3D printing of plastic material (ABS) and inkjet printing of silver nano-particle based metallic ink. The integration of lens enhances the gain by around 7 dB giving a peak gain of about 16.4 dBi at 9.4 GHz. The helical antenna operates in the end-fire mode and radiates a left-hand circularly polarized (LHCP) pattern. The 3-dB axial ratio (AR) bandwidth of the antenna with lens is 3.2 %. Due to integration of lens and fully printed processing, this antenna configuration offers high gain performance and requires low cost for manufacturing.

  13. Perforation forces of the intact porcine anterior lens capsule.

    Science.gov (United States)

    Ullrich, Franziska; Lussi, Jonas; Felekis, Dimitrios; Michels, Stephan; Petruska, Andrew J; Nelson, Bradley J

    2016-09-01

    During the first step of cataract surgery, the lens capsule is perforated and a circular hole is created with a sharp instrument, a procedure called capsulorhexis. To develop automated systems that can assist ophthalmologists during capsulorhexis, the forces required must be quantified. This study investigates perforation forces of the central anterior lens capsule in porcine eyes, which are used as a conservative model for the human eye. A micro-mechanical characterisation method is presented that measures capsular bag perforation forces with a high precision positioning and high-resolution force sensing system. The force during perforation of the anterior lens capsule was measured with various sized needles and indentation speeds and is found to be 15-35mN. A bio-mechanical model is identified that describes an exponential correlation between indentation force and depth, indicating strain hardening behaviour of the porcine anterior lens capsule.

  14. Fibroblast growth factor receptor signaling is essential for lens fiber cell differentiation

    OpenAIRE

    Zhao, Haotian; Yang, Tianyu; Madakashira, Bhavani P.; Thiels, Cornelius A.; Bechtle, Chad A.; Garcia, Claudia M.; Zhang, Huiming; Yu, Kai; Ornitz, David M.; Beebe, David C.; Robinson, Michael L.

    2008-01-01

    The vertebrate lens provides an excellent model to study the mechanisms that regulate terminal differentiation. Although fibroblast growth factors (FGFs) are thought to be important for lens cell differentiation, it is unclear which FGF receptors mediate these processes during different stages of lens development. Deletion of three FGF receptors (Fgfr1-3) early in lens development demonstrated that expression of only a single allele of Fgfr2 or Fgfr3 was sufficient for grossly normal lens dev...

  15. Late opacification of a hydrophilic acrylic intraocular lens

    Directory of Open Access Journals (Sweden)

    Al-Bdour Muawyah

    2008-01-01

    Full Text Available Cataract extraction and intraocular lens implantation is considered to be a safe procedure in most cases. However, the new advances in the surgical technique namely phacoemulsification and hence the increased use of foldable intraocular lenses have given rise to new complications including late opacification of intraocular lenses. In this case we report late opacification of a foldable hydrophilic acrylic intraocular lens and the surgical technique for its exchange.

  16. Supersymmetric black holes with lens-space topology.

    Science.gov (United States)

    Kunduri, Hari K; Lucietti, James

    2014-11-21

    We present a new supersymmetric, asymptotically flat, black hole solution to five-dimensional supergravity. It is regular on and outside an event horizon of lens-space topology L(2,1). It is the first example of an asymptotically flat black hole with lens-space topology. The solution is characterized by a charge, two angular momenta, and a magnetic flux through a noncontractible disk region ending on the horizon, with one constraint relating these.

  17. Signal-enhancement reflective pulse oximeter with Fresnel lens

    Science.gov (United States)

    Chung, Shuang-Chao; Sun, Ching-Cherng

    2016-09-01

    In this paper, a new reflective pulse oximeter is proposed and demonstrated with implanting a Fresnel lens, which enhances the reflected signal. An optical simulation model incorporated with human skin characteristics is presented to evaluate the capability of the Fresnel lens. In addition, the distance between the light emitting diode and the photodiode is optimized. Compared with the other reflective oximeters, the reflected signal light detected by the photodiode is enhanced to more than 140%.

  18. Design and simulation of large field plate lithography lens

    Science.gov (United States)

    Deng, Chao; Xing, Tingwen; Lin, Wumei; Zhu, Xianchang

    2016-10-01

    Because industry demand for LED,LCD panel continues to increase, the high yield of micron-scale resolution lithography is increasingly prominent for manufacturers, which requires the field of lithography objective lens becomes larger. This paper designed a lithography lens with large field, whose effective image side field will reach to 132 × 132mm.Subsequently, the tolerance was analysed by simulation for the optical system. Finally, it is proved that the design meets the requirements of micron-scale resolution.

  19. OPTICAL REALIZATION OF WAVELET TRANSFORM WITH A SINGLE LENS

    Institute of Scientific and Technical Information of China (English)

    王取泉; 熊贵光; 李承芳; 张苏淮; 王琳

    2001-01-01

    Two optical set-ups to implement wavelet transform with a single lens have been proposed, in which the wavelet filter was placed in front of the imaging lens or on the frequency plane. The general formula of the complex field distribution of the output plane has been deduced. The analysing wavelet functions of the band-pass wavelet filters with double and circular slits have been discussed.

  20. Adjusting to a sudden “aging” of the lens

    OpenAIRE

    Tregillus, KEM; Werner., JS; Webster, MA

    2016-01-01

    Color perception is known to remain largely stable across the lifespan despite the pronounced changes in sensitivity from factors such as the progressive brunescence of the lens. However, the mechanisms and timescales controlling these compensatory adjustments are still poorly understood. In a series of experiments, we tracked adaptation in observers after introducing a sudden change in lens density by having observers wear glasses with yellow filters that approximated the average spectral tr...

  1. Comparison of higher order aberrations and modulation transfer function with different intraocular lens to normal young phakic eyes%人工晶状体眼与正常年轻人眼高阶像差及调制传递函数对比分析

    Institute of Scientific and Technical Information of China (English)

    姜丽丽; 马忠旭; 王新; 高原; 孙龙格

    2014-01-01

    Objective To compare higher order aberrations (HOAs) and modulation transfer function (MTF) with postoperative cataract phacoemulsification and intraocular lens implantation with different IOLs to normal younger phakic eyes.Methods Base on spherical aberration of IOLs,the 80 cases (98 eyes) were divided into three groups:group Ⅰ spherical IOLs HQ201HEP,group Ⅱ aspheric IOL with zero aberration Akreos AO and group Ⅲ aspheric IOLs with negative aberration Tecnis ZA9003.Normal young phakic eyes were group ⅣV.Compute higher order aberrations and modulation transfer function of the patients of 3-month follow-up after cataract surgery and normal younger phakic eyes.Results Spherical aberration of four groups had statistically significant differences (P <0.05),except group Ⅲ and group ⅣV.The difference of coma between intraocular lens and normal young phakic eyes was statistically significant (P <0.05) while the differences between the different intraocular lens were no statistically significant (P >0.05).Total HOAs of four groups had statistically significant differences (P <0.05),except group Ⅰ and group Ⅱ.MTF(HOA) of eyes with intraocular lens was lower than normal young phakic eyes and the difference was statistically significant (P< 0.0083).MTF(HOA) of the three groups with different intraocular lens also had statistically significant differences (P <0.0083).Conclusions Aspheric IOLs can significantly reduce the spherical aberration and improve postoperative visual quality of the patients,especially the aspheric IOLs with negative sPherical aberration.However,there are differences between aspheric IOLs and normal young phakic eyes.%目的 比较白内障超声乳化吸除术后植入不同人工晶状体(IOL)眼与正常年轻人晶状体眼的高阶像差(HOAs)和调制传递函数(MTF).方法 回顾性病例系列研究.对于2012年4月至2013年1月在天津市眼科医院白内障中心行白内障超声乳化联合IOL植入术的80

  2. Adaptive neuro-fuzzy estimation of optimal lens system parameters

    Science.gov (United States)

    Petković, Dalibor; Pavlović, Nenad T.; Shamshirband, Shahaboddin; Mat Kiah, Miss Laiha; Badrul Anuar, Nor; Idna Idris, Mohd Yamani

    2014-04-01

    Due to the popularization of digital technology, the demand for high-quality digital products has become critical. The quantitative assessment of image quality is an important consideration in any type of imaging system. Therefore, developing a design that combines the requirements of good image quality is desirable. Lens system design represents a crucial factor for good image quality. Optimization procedure is the main part of the lens system design methodology. Lens system optimization is a complex non-linear optimization task, often with intricate physical constraints, for which there is no analytical solutions. Therefore lens system design provides ideal problems for intelligent optimization algorithms. There are many tools which can be used to measure optical performance. One very useful tool is the spot diagram. The spot diagram gives an indication of the image of a point object. In this paper, one optimization criterion for lens system, the spot size radius, is considered. This paper presents new lens optimization methods based on adaptive neuro-fuzzy inference strategy (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated.

  3. Lens Systems for Sky Surveys and Space Surveillance

    Science.gov (United States)

    Ackermann, M.; McGraw, J.; Zimmer, P.

    2013-09-01

    Since the early days of astrophotography, lens systems have played a key role in capturing images of the night sky. The first images were attempted with visual-refractors. These were soon followed with color-corrected refractors and finally specially designed photo-refractors. Being telescopes, these instruments were of long-focus and imaged narrow fields of view. Simple photographic lenses were soon put into service to capture wide-field images. These lenses also had the advantage of requiring shorter exposure times than possible using large refractors. Eventually, lenses were specifically designed for astrophotography. With the introduction of the Schmidt-camera and related catadioptric systems, the popularity of astrograph lenses declined, but surprisingly, a few remained in use. Over the last 30 years, as small CCDs have displaced large photographic plates, lens systems have again found favor for their ability to image great swaths of sky in a relatively small and simple package. In this paper, we follow the development of lens-based astrograph systems from their beginnings through the current use of both commercial and custom lens systems for sky surveys and space surveillance. Some of the optical milestones discussed include the early Petzval-type portrait lenses, the Ross astrographic lens and the current generation of optics such as the commercial 200mm camera lens by Canon, and the Russian VT-53e in service with ISON.

  4. Design of wide field and high resolution video lens

    Science.gov (United States)

    Xiao, Ze-xin; Zhan, Binzhou; Han, Haimei

    2009-11-01

    Online detecting is increasingly used in industrial process for the requirement of product quality improving. It is a trend that the "machine detecting" with "machine version + computer intelligence" as new method replaces traditional manual "eye observation". The essential of "machine detecting" is that image of object being collected with high resolution video lens on sensor panel of photoelectric (CCD ,CMOS) and detecting result being automatically gained by computer after the image saved and processed. "Machine detecting" is developing rapidly with the universal reception by enterprises because of its fine accurateness, high efficiency and the real time. Video lens is one of the important components of machine version system. Requirements of wide field and high resolution enlarged the complexity of video lens design. In this paper a design case used in visible light with field diameter Φ32mm, β=-0.25× and NA'=0.15. We give design parameters of the video lens which obtained with theoretically calculating and Oslo software optimization: MTF>0.3 in full field and 215lp/mm, distortion <0.05%.This lens has an excellent optic performance to match with 1.3 million pixels 1/2"CCD, and a high performance price ratio for being consist of only 7 single lens in the way of 5 units.

  5. The Embedded Transparent Lens and Fermat's Least-Time Principle

    CERN Document Server

    Kantowski, Ronald; Dai, Xinyu

    2013-01-01

    We present a much simplified version of the embedded point mass lens theory and then make the obvious extension of this theory to any embedded transparent lens. Embedding a lens effectively reduces the gravitational potential's range, i.e., partially shields the lensing potential because the lens mass is made a contributor to the mean mass density of the universe and not simply superimposed upon it. This presentation results from simplifying previous formulations of the embedded point mass theory and is quite similar to the standard theory. We are then able to re-derive the simplified point mass theory by applying Fermat's least-time principle to the time-delay function. Even though rigorous derivations are only made for the point mass, the lens equation to the lowest order for any distributed lens, is obvious. We find from this simplified theory that embedding can introduce corrections at the few percent level in weak lensing shears caused by large clusters but only at large impacts. The potential part of th...

  6. Bio-inspired fluidic lens surgical camera for MIS.

    Science.gov (United States)

    Tsai, Frank S; Johnson, Daniel; Cho, Sung Hwan; Qiao, Wen; Arianpour, Ashkan; Lo, Yu-Hwa

    2009-01-01

    We report a new type of surgical camera that will greatly improve minimally invasive surgery (MIS). The key enabling technology for this camera is a unique type of lens-bio-inspired fluidic lens, which is a bio-mimetic lens that can change its curvature, just like the way human crystalline lens can accommodate. Because of its curvature changing capability, it is now possible to design a new regime of optical systems where auto-focusing and optical zoom can be performed without moving the lens positions, as is done in typical cameras. Hence, miniaturized imaging system with high functionality can be achieved with such technology. MIS is a surgical technique where small incisions are made on the abdominal wall as opposed to a large cut in open surgery. This type of surgery ensures faster patient recovery. The key tool for MIS is its surgical camera, or laparoscope. Traditional laparoscope is long and rigid and limits the field of view. To further advance MIS technology, we utilized bio-inspired fluidic lens to design a highly versatile imager that is small, can change its field of view or zoom optically, works in low light conditions, and varies the viewing angles. The surgical camera prototype is small (total track<17 mm), possesses 3X optical zoom, operates with light emitting diode (LED) lighting, among many other unique features.

  7. Flat Lens Focusing Demonstrated With Left-Handed Metamaterial

    Science.gov (United States)

    Wilson, Jeffrey D.; Schwartz, Zachary D.; Chevalier, Christine T.; Downey, Alan N.; Vaden, Karl R.

    2004-01-01

    Left-handed metamaterials (LHM's) are a new media engineered to possess an effective negative index of refraction over a selected frequency range. This characteristic enables LHM's to exhibit physical properties never before observed. In particular, a negative index of refraction should cause electromagnetic radiation to refract or bend at a negative angle when entering an LHM, as shown in the figure above on the left. The figure on the right shows that this property could be used to bring radiation to a focus with a flat LHM lens. The advantage of a flat lens in comparison to a conventional curved lens is that the focal length could be varied simply by adjusting the distance between the lens and the electromagnetic wave source. In this in-house work, researchers at the NASA Glenn Research Center developed a computational model for LHM's with the three-dimensional electromagnetic commercial code Microwave Studio, constructed an LHM flat lens, and used it to experimentally demonstrate the reversed refraction and flat lens focusing of microwave radiation.

  8. Dark energy with gravitational lens time delays

    CERN Document Server

    Treu, T; Cyr-Racine, F -Y; Fassnacht, C D; Keeton, C R; Linder, E V; Moustakas, L A; Bradac, M; Buckley-Geer, E; Collett, T; Courbin, F; Dobler, G; Finley, D A; Hjorth, J; Kochanek, C S; Komatsu, E; Koopmans, L V E; Meylan, G; Natarajan, P; Oguri, M; Suyu, S H; Tewes, M; Wong, K C; Zabludoff, A I; Zaritsky, D; Anguita, T; Brunner, R J; Cabanac, R; Falco, E E; Fritz, A; Seidel, G; Howell, D A; Giocoli, C; Jackson, N; Lopez, S; Metcalf, R B; Motta, V; Verdugo, T

    2013-01-01

    Strong lensing gravitational time delays are a powerful and cost effective probe of dark energy. Recent studies have shown that a single lens can provide a distance measurement with 6-7 % accuracy (including random and systematic uncertainties), provided sufficient data are available to determine the time delay and reconstruct the gravitational potential of the deflector. Gravitational-time delays are a low redshift (z~0-2) probe and thus allow one to break degeneracies in the interpretation of data from higher-redshift probes like the cosmic microwave background in terms of the dark energy equation of state. Current studies are limited by the size of the sample of known lensed quasars, but this situation is about to change. Even in this decade, wide field imaging surveys are likely to discover thousands of lensed quasars, enabling the targeted study of ~100 of these systems and resulting in substantial gains in the dark energy figure of merit. In the next decade, a further order of magnitude improvement will...

  9. The correction of electron lens aberrations

    Energy Technology Data Exchange (ETDEWEB)

    Hawkes, P.W., E-mail: peter.hawkes@cemes.fr

    2015-09-15

    The progress of electron lens aberration correction from about 1990 onwards is chronicled. Reasonably complete lists of publications on this and related topics are appended. A present for Max Haider and Ondrej Krivanek in the year of their 65th birthdays. By a happy coincidence, this review was completed in the year that both Max Haider and Ondrej Krivanek reached the age of 65. It is a pleasure to dedicate it to the two leading actors in the saga of aberration corrector design and construction. They would both wish to associate their colleagues with such a tribute but it is the names of Haider and Krivanek (not forgetting Joachim Zach) that will remain in the annals of electron optics, next to that of Harald Rose. I am proud to know that both regard me as a friend as well as a colleague. - Highlights: • Geometrical aberration correction. • Chromatic aberration correction. • 50 pm resolution. • High-resolution electron energy-loss spectroscopy. • Extensive bibliographies.

  10. Hemispherical projection lens for insect behavior analysis

    Science.gov (United States)

    Aikio, Mika; Takalo, Jouni; Lempeä, Mikko; Vähäsöyrinki, Mikko

    2010-05-01

    Virtual reality projection systems have been used formerly to study if mammals, including humans, are able to act in or understand virtual environments. Insects have been more difficult to study in such circumstances, one of the factors being their large, almost hemispherical field of view. Designing such a projection system that is capable of fulfilling the full field of vision of an insect is a challenging task. Normally, when designing a photographic objective, one of the goals is to minimize field curvature in order to provide sharp image through the whole sensor surface. However, because the image surface in this case is a sphere, flat field is not desirable and the design task becomes an opposite of a typical camera lens. Introducing field curvature becomes mandatory. We have designed and built a system with satisfactory image quality throughout the whole spherical surface with reasonable number of lenses as an add-on for common digital projectors. The manufactured system is able to project an image to a solid angle of 11.95 steradians, and when compared to the whole sphere which is represented with a solid angle of 4π steradians, approximately 5 % of the total sphere area is not illuminated.

  11. Testing convex aspherical surfaces with optimized modified Hindle arrangement%改进的Hindle方法检测凸非球面的研究

    Institute of Scientific and Technical Information of China (English)

    马杰; 朱政

    2011-01-01

    It is difficult to fabricate and test convex aspherical surfaces, especially for fast-focal-ratio,large-aperture convex aspheical surfaces. To solve this problem, a modified Hindle arrangement was discussed, which can avoid central obscuration, overmuch large aperture of auxiliary mirror and other limitations of conventional testing methods. But there was a shortcoming that the glass substrate would require a reflective coating for each test cycle to get enough reflected light for testing in original arrangement. In order to overcome this disadvantage, the method was analyzed and optimized. As a result,it became more simpler and overcame the shortcoming of restriction on reflectivity of mirror under test.The experiment of testing and fabricating a hyperboloid glass mirror (Φ 88, F/1.9) was carried out to examine the feasibility of optimized arrangement. After fabrication, the root-mean-square (RMS) of the mirror was 0.020λ, which was given by a WYKO digital interferometer. The test result and further analysis show that the optimized modified Hindle arrangement can test more kinds of convex aspherical surfaces than previous solutions, and is demonstrated to be an effective, high-precision testing method.%凸非球面,尤其是大口径快焦比凸非球面的光学检验一直是非球面加工中的难点.针对凸非球面光学元件加工检验困难的问题.研究了一种改进的Hindle方法.解决了经典的Hindle方法需要大口径辅助球面镜和存在中心遮挡等不足.利用该方法对一块φ88 mm.焦比F/1.9的玻璃材料凸双曲面镜进行检验加工实验,对系统进行了分析优化,简化了检验光路的结构,克服了此种改进的Hindle方法检验时被检镜需要镀膜的缺陷,简化了加工工艺流程,极大地拓宽了该方法的适用范围.加工完成后经移相式数字干涉仪检测,镜面均方根(RMS)误差为0.020A,验证了优化后方法的可行性.检验结果和对系统的进一步分析表明:经

  12. Comparison of clinical outcomes in PRK with a standard and aspherical optimized profile: a full case analysis of 100 eyes with 1-year follow-up

    Directory of Open Access Journals (Sweden)

    Dausch D

    2014-11-01

    Full Text Available Dieter Dausch,1,2 Burglinde Dausch,2 Matthias Wottke,3 Georg Sluyterman van Langeweyde31Chung-Ang University, Seoul, South Korea; 2Augen-Laser-Klinik Nürnberg, Nuremberg, Germany; 3Carl Zeiss Meditec AG, Jena, Germany Purpose: One hundred eyes from 55 adult patients with myopia were retrospectively studied to determine the comparative safety, efficacy, and predictability of aberration smart ablation (ASA and a new advanced ablation algorithm (Triple-A using the MEL® 80 excimer laser.Methods: Fifty myopic eyes with a manifest refraction spherical equivalent (MRSE between -1.0 diopters (D and -9.75 D were consecutively treated with photorefractive keratectomy ASA, and 50 myopic eyes with an MRSE between -1.38 D and -11.0 D with photorefractive keratectomy Triple-A. Uncorrected distance visual acuity, MRSE, the absolute value of the cylinder, corrected distance visual acuity, and postoperative complications at 1 month, 3 months, 6 months, and 12 months (1 year were descriptively analyzed and compared at 1 year.Results: After 12 months, the MRSE variance was statistically significantly better in patients triaged to receive Triple-A compared with patients receiving ASA (ASA, ±0.7 D; Triple-A, ±0.15 D; P<0.001. Furthermore, no patient in the Triple-A group had any cylinder postoperatively. Patients in the Triple-A treatment arm achieved a superior result. No statistically significant difference in the two treatment arms was noted for the analysis of the mean MRSE at 12 months (P=0.78.Conclusion: Triple-A was more effective than standard aspherical surgical intervention in a number of treatment outcome parameters (eg, MRSE, astigmatism, efficacy index. The two surgical procedures were equivalent in terms of safety. Keywords: aberration smart ablation (ASA, manifest refraction spherical equivalent, Triple-A advanced ablation algorithm, uncorrected distance visual acuity, corrected distance visual acuity, excimer laser, PRK, ablation profile

  13. 亲水性非球面与球面人工晶状体植入术后高阶像差的研究%Higher order aberrations in eyes implanted with aspheric vs spherical hydrophilic intraocular lenses

    Institute of Scientific and Technical Information of China (English)

    Ibrahim Kocak; Faruk Kaya; Hakan Baybora

    2012-01-01

    AIM: To compare the effect of spherical and aspheric hydrophilic intraocular lenses (IOL) on postoperative higher order aberrations (HOA). METHODS: Uneventful phacoemulsification was performed in 78 eyes of 66 patients with implanting either spherical Softec or aspheric Ocuva lenses. Preoperative and postoperative 3rd month aberrometry was performed with Visx Wavescan aberrometer to be compared. RESULTS: There was no statistically significant difference between two groups. Postoperative root-mean-square (RMS) value of HOA: 0.27±0.11 in Softec and 0.28±0.13 in Ocuva group, spherical aberration (SA): 0.11±0.07 in Softec and 0.11±0.08 in Ocuva group. CONCLUSION: Aspheric Ocuva IOL seems not to have an advantage of decreasing postoperative HOA compared to spherical Softec IOL.%目的:比较亲水性球面和非球面人工晶状体(intraocular lenses,IOL)对术后高阶像差(higher order aberrations,HOA)的影响.方法:66例78眼行白内障超声乳化术并顺利植入球面Softec或者非球面Ocuva人工晶状体.术前和术后第3mo使用VISX Wavescan像差计进行像差测量与比较.结果:两组间统计学无显著性差异.术后的高阶像差均方根值(root-mean-square,RMS):Softec组0.27±0.11,Ocuva组0.28±0.13,球面像差(spherical aberration,SA):Softec组0.11±0.07,Ocuva组0.11±0.08.结论:与球面Softec人工晶状体比较,Ocuva非球面人工晶状体似乎没有减少术后高阶像差的优势.

  14. Development of an accommodating intra-ocular lens - In vitro prevention of re-growth of pig and rabbit lens capsule epithelial cells

    NARCIS (Netherlands)

    van Kooten, Theo G.; Koopmans, Steven; Terwee, Thom; Norrby, Sverker; Hooymans, J. M. M.; Busscher, Henk J.

    2006-01-01

    Cataract surgery is routinely performed to replace the clouded lens by a rigid polymeric intra-ocular lens unable to accommodate. By implanting a silicone gel into an intact capsular bag the accommodating properties of the natural lens can be maintained or enhanced. The implantation success of accom

  15. A role for smoothened during murine lens and cornea development.

    Directory of Open Access Journals (Sweden)

    Janet J Y Choi

    Full Text Available Various studies suggest that Hedgehog (Hh signalling plays roles in human and zebrafish ocular development. Recent studies (Kerr et al., Invest Ophthalmol Vis Sci. 2012; 53, 3316-30 showed that conditionally activating Hh signals promotes murine lens epithelial cell proliferation and disrupts fibre differentiation. In this study we examined the expression of the Hh pathway and the requirement for the Smoothened gene in murine lens development. Expression of Hh pathway components in developing lens was examined by RT-PCR, immunofluorescence and in situ hybridisation. The requirement of Smo in lens development was determined by conditional loss-of-function mutations, using LeCre and MLR10 Cre transgenic mice. The phenotype of mutant mice was examined by immunofluorescence for various markers of cell cycle, lens and cornea differentiation. Hh pathway components (Ptch1, Smo, Gli2, Gli3 were detected in lens epithelium from E12.5. Gli2 was particularly localised to mitotic nuclei and, at E13.5, Gli3 exhibited a shift from cytosol to nucleus, suggesting distinct roles for these transcription factors. Conditional deletion of Smo, from ∼E12.5 (MLR10 Cre did not affect ocular development, whereas deletion from ∼E9.5 (LeCre resulted in lens and corneal defects from E14.5. Mutant lenses were smaller and showed normal expression of p57Kip2, c-Maf, E-cadherin and Pax6, reduced expression of FoxE3 and Ptch1 and decreased nuclear Hes1. There was normal G1-S phase but decreased G2-M phase transition at E16.5 and epithelial cell death from E14.5-E16.5. Mutant corneas were thicker due to aberrant migration of Nrp2+ cells from the extraocular mesenchyme, resulting in delayed corneal endothelial but normal epithelial differentiation. These results indicate the Hh pathway is required during a discrete period (E9.5-E12.5 in lens development to regulate lens epithelial cell proliferation, survival and FoxE3 expression. Defective corneal development occurs

  16. 用于凹非球面的计算全息设计及其误差分析%Design and Error Analysis of the Computer-Generated Helogram Used for Concave Aspheric Surface Testing

    Institute of Scientific and Technical Information of China (English)

    冯婕; 邓超; 邢廷文

    2012-01-01

    In order to test concave aspheric surfaces precisely, a multifunctional computer-genera ted hologram (CGH) which can compensate wavefront in null test, adjust the relative position between CGH and interferometer and adjust the relative position between CGH and the tested aspheric surface is proposed and designed. It consists of three segments, called main CGH, alignment CGH and fiducial CGH. The principle of testing aspheric surfaces is reviewed and the design method is introduced. The pros and cons of the auxiliary CGH adjustment method and the common adjustment method are compared. Then a design example for testing a paraboloidal mirror (Φ187.72 mm、F number is 1.71) is presented. The effects of CGH fabrication errors on the accuracy of interferometric measurements are analyzed. The accuracy of using a CGH to measure the surface is 4. 47 nm. The designed CGH meets the requirements of high precision aspheric surfaces testing.%为实现非球面元件表面面形的高精度检测,提出并设计了一种兼具相位补偿、装调计算全息图(CGH)和待测非球面的多功能计算全息图.多功能计算全息图由主全息、对准全息和基准全息3部分组成.介绍了各部分的工作原理及其设计方法,比较了辅助全息装调方法和普通装调方法的优劣,并给出了检测Φ187.72 mm、F数为1.71的凹非球面镜的计算全息设计实例,分析了影响全息检测精度的各项误差源,计算得出所设计的计算全息的检测精度可达4.75 nm,实现了非球面元件面形的高精度检测.

  17. Evaluation of resources for contact lens practice in private contact lens clinics of Muscat, Oman

    Directory of Open Access Journals (Sweden)

    Rajiv Khandekar

    2009-01-01

    Materials and Methods: This study was conducted between May and July 2006. A team of optometrists and health inspectors visited clinics and collected information about the infrastructure, available human resources, and materials used in the CL practice. We used a pre-tested close-ended questionnaire to collect responses of the practitioners and observations of the field staff. Statistical Method: Univariate parametric type of analysis. Results: The team visited 67 CL clinics and interviewed 75 CL practitioners. Proper hand washing facility was available at 61 clinics. Thirty-nine practitioners had> 10 years of experience in dispensing contact lenses. Only 13 clinics had a bio-microscope. None of the clinics had legal documents signed by both providers and end users of the contact lens. Conclusions: Contact lens has received less attention in areas outside the developed world. The CL practice in the private sectors of Oman needs to be strengthened. Minimum standards, standard operating procedures for CL practice, and its periodic supervision would be useful.

  18. Evaluating the cytotoxicity of contact lens multi-purpose solutions in an in vitro lens system

    Directory of Open Access Journals (Sweden)

    O. Matthew Oriowo

    2009-12-01

    Full Text Available Purpose: To investigate the relative cytotoxic effects of contact lens multipurpose solutions on cultured crystalline lenses.Methods: A comparison of the fluorescence emission levels of cultured bovine lenses as affected by three hour experimental exposure to three contact lens multipurpose solutions (COMPLETE Moisture Plus, AMO; OPTI-FREE Express, Alcon; and ReNu MultiPlus, Bausch & Lomb was carried out. The pre- and post-exposure fluorescence levels of the lenses were obtained and values were compared to baseline and control measurements.Results: The solutions yielded varying degrees of cytotoxicity, demonstrating significant (p < 0.01 reversible reduction of cellular viability levels of the cultured crystalline lenses as revealed by the degree of fluorescence emissions in the following order (OPTI-FREE Express > ReNu MultiPlus > COMPLETE MoisturePlus multi-purpose solutionsConclusions: The results show that OPTI-FREE Express and ReNu MultiPlus solutions exhibited more cytotoxic effect compared to COMPLETE MoisturePlus solution. The findings support reportsfrom previous clinical and laboratory studies. These results suggest that the in vitro approach herein presented would be a valuable system for relatively inexpensive and repeatable laboratory investigations of the possible ocular surface reactions of ophthal-mic solutions, cosmetics and pharmaceuticals at pre- and during commercial phases. 

  19. Negative refractive perfect lens vs Spherical geodesic lens. Perfect Imaging comparative analysis

    CERN Document Server

    Gonzalez, Juan C; Minano, Juan C; Grabovickic, Dejan

    2012-01-01

    Negative Refractive Lens (NRL) has shown that an optical system can produce images with details below the classic Abbe diffraction limit. This optical system transmits the electric field, emitted by the object surface, towards the image surface producing the same field distribution in both surfaces. In particular, a Dirac delta electric field in the object surface is focused without diffraction limit to the Dirac delta electric field in the image surface. The Maxwell Fish Eye lens (MFE) and the Spherical Geodesic Waveguide (SGW) have been claimed to break the diffraction limit using positive refraction with a different meaning. In these cases, it has been considered the power transmission from a point source to a point receptor, which falls drastically when the receptor is displaced from the focus by a distance much smaller than the wavelength. Although these systems can detect displacements up to Wavelength/500, they cannot be compared to the NRL, since the concept of the object and image surface is not esta...

  20. Monitoring the eye lens: which dose quantity is adequate?

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, R [Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig (Germany); Dietze, G, E-mail: rolf.behrens@ptb.d [Paracelsusstrasse 7, D-38116 Braunschweig (Germany)

    2010-07-21

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. The question of which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens arises from this situation. While in many countries dosemeters calibrated in terms of the dose equivalent quantity H{sub p}(0.07) have been seen as being adequate for monitoring the dose to the eye lens, this might be questionable in the case of reduced dose limits and, thus, it may become necessary to use the dose equivalent quantity H{sub p}(3) for this purpose. To discuss this question, the dose conversion coefficients for the equivalent dose of the eye lens (in the following eye lens dose) were determined for realistic photon and beta radiation fields and compared with the values of the corresponding conversion coefficients for the different operational quantities. The values obtained lead to the following conclusions: in radiation fields where most of the dose comes from photons, especially x-rays, it is appropriate to use dosemeters calibrated in terms of H{sub p}(0.07) on a slab phantom, while in other radiation fields (dominated by beta radiation or unknown contributions of photon and beta radiation) dosemeters calibrated in terms of H{sub p}(3) on a slab phantom should be used. As an alternative, dosemeters calibrated in terms of H{sub p}(0.07) on a slab phantom could also be used; however, in radiation fields containing beta radiation with the end point energy near 1 MeV, an overestimation of the eye lens dose by up to a factor of 550 is possible.