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Sample records for aspherical compound lens

  1. Scanning fiber-optic nonlinear endomicroscopy with miniature aspherical compound lens and multimode fiber collector

    OpenAIRE

    Wu, Yicong; Xi, Jiefeng; Cobb, Michael J.; Li, Xingde

    2009-01-01

    A flexible scanning fiber-optic endomicroscope using a miniature compound lens and a multimode-fiber (MMF) collector was developed for two-photon fluorescence (TPF) and second-harmonic generation (SHG) imaging. The compound lens consisted of a pair of aspherical lenses and exhibited reduced chromatic aberration compared with gradient-index lenses, thus increasing the TPF/SHG collection efficiency. The introduction of a short MMF collector at the distal end of the double-clad fiber of the endo...

  2. Shape measurement of aspheric plastic lens with large angle

    Institute of Scientific and Technical Information of China (English)

    Dagang Huang; Heng Zhang; Shah-Rong Lee; Baoguang Wang

    2005-01-01

    @@ In this paper, according to the features of easy distortion and scratch for aspheric plastic lens, a noncontact measuring method is raised to test error in shape of the lens. Namely, the distance between a template and its image reflected with tested lens can be measured in nearly the vertical direction of the lens axis when the two-dimensional (2D) template is put near the measured surface. Then, the outline of the central cross-section could be obtained by calculating and curve fitting. Furthermore, three-dimensional (3D) surface can be imitated through rotating the component. A new fitting method of drift measurement is presented to prevent reducing precision when the lens and the template are fixed. The template is adjusted according to the position of the lens. The measurement precision is in the order of magnitued of sub-microns. Rotationally symmetric convex aspheric surface with any angle can be measured by this method.

  3. Surface topography of parallel grinding process for nonaxisymmetric aspheric lens

    International Nuclear Information System (INIS)

    Workpiece surface profile, texture and roughness can be predicted by modeling the topography of wheel surface and modeling kinematics of grinding process, which compose an important part of precision grinding process theory. Parallel grinding technology is an important method for nonaxisymmetric aspheric lens machining, but there is few report on relevant simulation. In this paper, a simulation method based on parallel grinding for precision machining of aspheric lens is proposed. The method combines modeling the random surface of wheel and modeling the single grain track based on arc wheel contact points. Then, a mathematical algorithm for surface topography is proposed and applied in conditions of different machining parameters. The consistence between the results of simulation and test proves that the algorithm is correct and efficient. (authors)

  4. 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.

  5. Residue stress analysis of molding aspherical plastic lens

    Science.gov (United States)

    Hsu, Ming-Ying; Cheng, Yuan-Chieh; Chang, Shenq-Tsong; Huang, Ting-Ming

    2015-09-01

    The aspherical plastic lens is widely used in commercial optical products. Warpage and residue stress are two important factors that influence wavefront error. Several investigators have discussed warpage. We propose a methodology to study the effect of residue stress on wavefront error. Mold flow software was adopted to calculate the residue stress in injection processes. Optical software was used to find optical ray paths through the lens. Corresponding Optical Path Different (OPD) in each ray path was simulated by self-developed software. A 50-mm diameter plastic lens was used in this study. The mild- and high-frequency wavefront errors and the stress OPD effect at the injection area were found to be a result of the molding process. The proposed methodology was found to be very suitable for finding the effect of residue stress on wavefront error in plastic lenses.

  6. A framework of cloud supported collaborative design in glass lens moulds based on aspheric measurement

    Science.gov (United States)

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

    2013-09-01

    Aspheric mould design includes the top-down design and reversal design. In this paper, a new framework of reversal design is proposed combining with cloud supported collaborative design (CSCD) based on aspheric measurement. The framework is a kind of collaborative platform, which is composed of eight modules, including the computerized aspheric precision measurement module (CAPM), computer-aided optical design of aspheric lens system (CAOD), computer-aided design of lens mould (CADLM), FEM(finite element method) simulation of lens molding module (FEMLM), computer-aided manufacture of lens and moulds (CAMLM), measurement data analysis module (MDAM), optical product lifecycle management module (OPLM) and cloud computing network module (CCNM). In this framework, the remote clients send an improved requirement or fabrication demand about optical lens system through CCNM, which transfers this signal to OPLM. In OPLM, one main server is in charge of the task distribution and collaborative work of other six modules. The first measurement data of aspheric lens are produced by clients or our proposed platform CAPM, then are sent to CAOD for optimization and the electronic drawings of lens moulds are generated in CADLM module. According the design drawings, the FEMLM could give the lens-molding simulation parameters through FEM software. The simulation data are used for the second design of moulds in CADLM module. In this case, the moulds could be fabricated in CAMLM by ultra-precision machine, and the aspheric lens could be also produced by lens-molding machine in CAMLM. At last, the final shape of aspheric lens could be measured in CAPM and the data analysis could be conducted in MDAM module. Through the proposed framework, all the work described above could be performed coordinately. And the optimum design data of lens mould could be realized and saved, then shared by all the work team.

  7. Research on the polishing technology of high-precision aspherical cylindrical lens

    Science.gov (United States)

    Fu, Xiu-hua; Wang, Zhe; Jia, Zong-he; Dong, Huan; Liu, Dan; Zhang, Chuan-xin

    2014-08-01

    Aspherical cylindrical lens compared with the cylindrical lens, they improved image quality and optical properties, simplified the system architecture. They applied in many fields, such as high power laser system, fax machines and typographical scan imaging system, as well as bar code scanning, lighting and other aspects of holography. Aspherical cylindrical lens are centrosymmetric. It is difficult to process. Parallel with the side line and bus bar line is difficult to ensure. Machining accuracy is low. It is usually about 15 μm, that not sufficient to meet the needs of modern highprecision laser systems. These have become a major problem restricting its development. Combining traditional and modern polishing techniques, a new technique for polishing aspherical cylindrical lens is proposed-- longitudinal feedback compensation technology. With dimensions of 15 × 5 × 5 mm quartz aspherical cylindrical lens as an example, the surface profilometer results of detection of the workpiece usually, modify the shape of the polishing surface of the mold, to control the size of the area of the polishing, the surface of the workpiece to achieve the effect of the type of compensation. After repeated testing and feedback compensation, gradually improve the accuracy of the workpiece surface type. The results show that this technique can effectively improve the precision aspherical cylindrical lens. After detection the workpiece surface accuracy is 0.8μm, the surface finish is Class II. It has the actual production of a certain application value.

  8. Simulation of an Aspheric Glass Lens Forming Behavior in Progressive GMP Process

    International Nuclear Information System (INIS)

    Recently, GMP(Glass Molding Press) process is mainly used to produce aspheric glass lenses. Because glass lens is heated at high temperature above Tg (Transformation Temperature) for forming the glass, the quality of aspheric glass lens is deteriorated by residual stresses which are generated in a aspheric glass lens after forming. In this study, as a fundamental study to develop the mold for progressive GMP process, we conducted a aspheric glass lens forming simulation. Prior to a aspheric glass lens forming simulation, compression and thermal conductivity tests were carried out to obtain mechanical and thermal properties of K-PBK40 which is newly developed material for precision molding, and flow characteristics of K-PBK40 were obtained at high temperature. Then, using the flow characteristics obtained, compression simulation was carried out and compared with the experimental result for the purpose of verifying the obtained flow characteristics. Finally, a glass lens press simulation in progressive GMP process was carried out and we could forecast the shape of deformed glass lenses and residual stresses contribution in the structure of deformed glass lenses after forming

  9. Problems in the application of a null lens for precise measurements of aspheric mirrors.

    Science.gov (United States)

    Chkhalo, N I; Malyshev, I V; Pestov, A E; Polkovnikov, V N; Salashchenko, N N; Toropov, M N; Soloviev, A A

    2016-01-20

    Problems in the application of a null lens for surface shape measurements of aspherical mirrors are discussed using the example of manufacturing an aspherical concave mirror for the beyond extreme ultraviolet nanolithographer. A method for allowing measurement of the surface shape of a sample under study and the aberration of a null lens simultaneously, and for evaluating measurement accuracy, is described. Using this method, we made a mirror with an aspheric surface of the 6th order (i.e., the maximum deviation from the best-fit sphere is 6.6 μm) with the parameters of the deviations from the designed surface PV=5.3  nm and RMS=0.8  nm. An approximation of the surface shape was carried out using Zernike polynomials {Z(n)(m)(r,φ),m+n≤36}. The physical limitations of this technique are analyzed. It is shown that for aspheric measurements to an Angstrom accuracy, one needs to have a null lens with errors of less than 1 nm. For accurate measurements, it is necessary to establish compliance with the coordinates on the sample and on the interferogram. PMID:26835938

  10. 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.

  11. 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.

  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. Contrast visual acuity after multifocal intraocular lens implantation:aspheric versus spherical design

    Directory of Open Access Journals (Sweden)

    Jun-Hua Li

    2014-02-01

    Full Text Available AIM: To evaluate contrast visual acuity (CVA after implantation of an aspheric apodized diffractive intraocular lens (IOL or a spherical apodized diffractive IOL in cataract surgery.METHOD: This prospective randomized controlled study with a 12-month follow-up compared the results of cataract surgery with implantation of an aspheric AcrySof ReSTOR SN6AD3 IOL (30 eyes and a spherical AcrySof ReSTOR SN60D3 IOL (30 eyes. CVA with best distance correction was measured at 4 contrast levels (100%, 25%, 10% and 5% under 3 levels of chart luminance [250, 85 and 25 candelas per square meter (cd/m2] using a multi-functional visual acuity tester (MFVA-100.RESULTS:At 12 months after surgery, there were no statistically significant differences in 100% CVA and 25% CVA under 250cd/m2 (P100%=0.875 and P25%=0.057 and 85cd/m2 (P100%=0.198 and P25%=0.193 between the aspheric group and the spherical group. However, the 10% CVA and 5% CVA were significant better in aspheric group than spherical group under 250cd/m2 (P10%=0.042 and P5%=0.007 and 85cd/m2 (P10%=0.002 and P5%=0.039. Under the luminance level of 25cd/m2, no significant differences was found in the 100% CVA between the 2 group (P100%=0.245, while aspheric group had better visual acuity in the remaining 3 contracts (P25%=0.023, P10%=0.026 and P5%=0.002, respectively.CONCULSION:The aspheric AcrySof ReSTOR SN6AD3 IOL provided patients with better low-contrast visual acuity than the spherical AcrySof ReSTOR SN60D3 IOL.Keyword:cataract surgery; intraocular lens; contrast sensitivity; visual acuity

  14. Optimum electrostatic force control for fabricating a hybrid UV-curable aspheric lens

    International Nuclear Information System (INIS)

    The purpose of this paper is to use a hybrid structure and the electrostatic force to fabricate aspheric lenses with high optical transmittance (95% at 405 nm). The hybrid structure is composed of Norland Optical Adhesive 63 (NOA63) (refractive index: 1.5802 at 405 nm) and BK-7 glass (refractive index: 1.5302). OSLO (Optics Software for Layout and Optimization) and CFD (Computational Fluid Dynamics) software packages were used to simulate the electric field gradient between the top and bottom electrodes and to produce the optimum bottom electrode design. Different electrode designs were also tested in order to optimize the morphology of the lens profile. The resulting lens profiles have clear apertures of approximately 0.92 mm with maximum shape errors of less than 0.18% and the spot size of the fabricated aspheric lenses can be controlled to approximately 0.504 µm. This technology can be used as a generic approach to fabricate lenses for applications in various micro-optical systems.

  15. Clinical performance of a new aspheric dual-optic accommodating intraocular lens

    Directory of Open Access Journals (Sweden)

    Marques EF

    2014-11-01

    Full Text Available Eduardo F Marques,1 António Castanheira-Dinis2 1Department of Ophthalmology, Hospital da Cruz Vermelha, Lisboa, Portugal; 2Visual Sciences Research Centre, Universidade de Lisboa, Portugal Purpose: To describe the clinical performance of a new dual-optic intraocular lens (IOL with an enhanced optic profile designed to mimic natural accommodation.Patients and methods: Prospective multicenter clinical study with the new dual-optic aspheric accommodating IOL (Synchrony Vu in 74 patients (148 eyes undergoing cataract surgery. Refractive target was emmetropia. Examinations at 1 month and 6 months included subjective refractions; visual acuities at near, intermediate, and far; mesopic contrast sensitivity with and without glare; safety data; and subjective survey on dysphotopsia (halos and glare.Results: Clinical data at 6 months showed 89% of the eyes within ±1.0 D spherical equivalent refraction. Mean binocular uncorrected and distance-corrected visual acuity was 20/20 at far (0.00±0.11 logMAR and -0.06±0.08 logMAR, respectively, 20/20 at intermediate (0.01±0.13 logMAR and -0.01±0.10 logMAR, respectively, and 20/25 at near (0.10±0.14 logMAR and 0.14±0.15 logMAR, respectively. Mesopic contrast sensitivity was within normal limits. Seventy-eight percent of the patients had no spectacles and 70% had no dysphotopsia. One eye had IOL repositioning within 1 month of surgery.Conclusion: The new aspheric Synchrony Vu accommodating IOL provided good visual performance at a range of distances without affecting quality of vision and with minimal safety considerations. Keywords: accommodating IOL, cataract surgery, intraocular lens, presbyopia

  16. Theoretical and experimental research on error analysis and optimization of tool path in fabricating aspheric compound eyes by precision micro milling

    Science.gov (United States)

    Chen, Mingjun; Xiao, Yong; Tian, Wenlan; Wu, Chunya; Chu, Xin

    2014-05-01

    Structure design and fabricating methods of three-dimensional (3D) artificial spherical compound eyes have been researched by many scholars. Micro-nano optical manufacturing is mostly used to process 3D artificial compound eyes. However, spherical optical compound eyes are less at optical performance than the eyes of insects, and it is difficult to further improve the imaging quality of compound eyes by means of micro-nano optical manufacturing. In this research, nonhomogeneous aspheric compound eyes (ACEs) are designed and fabricated. The nonhomogeneous aspheric structure is applied to calibrate the spherical aberration. Micro milling with advantages in processing three-dimensional micro structures is adopted to manufacture ACEs. In order to obtain ACEs with high imaging quality, the tool paths are optimized by analyzing the influence factors consisting of interpolation allowable error, scallop height and tool path pattern. In the experiments, two kinds of ACEs are manufactured by micro-milling with different too path patterns and cutting parameter on the miniature precision five-axis milling machine tool. The experimental results indicate that the ACEs of high surface quality can be achieved by circularly milling small micro-lens individually with changeable cutting depth. A prototype of the aspheric compound eye (ACE) with surface roughness ( R a) below 0.12 μm is obtained with good imaging performance. This research ameliorates the imaging quality of 3D artificial compound eyes, and the proposed method of micro-milling can improve surface processing quality of compound eyes.

  17. Quality of vision in patients implanted with aspherical and spherical intraocular lens: Intraindividual comparison

    Directory of Open Access Journals (Sweden)

    Francesco Semeraro

    2014-01-01

    Full Text Available Aims: To compare the quality of vision in pseudophakic patients implanted with aspherical and spherical intraocular lenses (IOLs. Materials and Methods: Randomized prospective longitudinal intrapatient comparison between aspherical and spherical IOLs performed on 22 patients who underwent bilateral cataract surgery. Best corrected visual acuity, subjective contrast sensitivity, Strehl ratio and spherical aberrations (SA, and higher order wavefront aberrations for a 3.5 mm and a 6.0 mm pupil were measured after 3 months of cataract surgery. Results: SA (Z4,0 decreased significantly in eyes with aspherical IOL implant (P = 0.004. Modulation transfer function (MTF and point spread function (PSF resulted no significant difference between the two groups (P = 0.87; P = 0.32. Conclusion: Although the SA is significantly lower in eyes implanted with aspherical IOL, the quality of vision determined with MTF and PSF does not significantly differ for subjective and objective parameters that were analyzed.

  18. 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.

  19. Research on axisymmetric aspheric surface numerical design and manufacturing technology

    Science.gov (United States)

    Wang, Zhen-zhong; Guo, Yin-biao; Lin, Zheng

    2006-02-01

    The key technology for aspheric machining offers exact machining path and machining aspheric lens with high accuracy and efficiency, in spite of the development of traditional manual manufacturing into nowadays numerical control (NC) machining. This paper presents a mathematical model between virtual cone and aspheric surface equations, and discusses the technology of uniform wear of grinding wheel and error compensation in aspheric machining. Finally, a software system for high precision aspheric surface manufacturing is designed and realized, based on the mentioned above. This software system can work out grinding wheel path according to input parameters and generate machining NC programs of aspheric surfaces.

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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

    2015-02-01

    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. PMID:25393218

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

    OpenAIRE

    Lei Jing; Hua Liu; Huifu Zhao; Zhenwu Lu; Hongsheng Wu; He Wang; Jialin Xu

    2012-01-01

    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 p...

  6. Design of Hartmann type null screens for testing a plano-convex aspheric lens with a CCD sensor inside the caustic.

    Science.gov (United States)

    Castillo-Santiago, Gabriel; Castán-Ricaño, Diana; Avendaño-Alejo, Maximino; Castañeda, Luis; Díaz-Uribe, Rufino

    2016-08-22

    A new method to design Hartmann type null screens to test either qualitatively or quantitatively fast plano-convex aspherical lenses is presented. We design both radial and square null screens that produce arrays of circular spots uniformly distributed at predefined planes, considering that the CCD sensor is solely placed inside the caustic region. The designs of these null screens are based on knowledge of the caustic by refraction and on exact ray tracing. The null screens also serve to improve the alignment in optical systems. PMID:27557218

  7. 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.

  8. High transmission Ni compound refractive lens for high energy X-rays

    Science.gov (United States)

    Brancewicz, M.; Itou, M.; Sakurai, Y.; Andrejczuk, A.; Chiba, S.; Kayahara, Y.; Inoue, T.; Nagamine, M.

    2016-08-01

    We present a new planar Ni compound refractive lens for high energy X-rays (116 keV). The lens is composed of identical plano-concave elements with longitudinal parabolic grooves manufactured by a punch technique. In order to increase the lens transmission, the thickness of the single lens at the parabolic groove vertex was reduced to less than 5 μm and the radius of curvature was reduced to about 20 μm. The small radius of curvature allowed us to reduce the number of single elements needed to get the focal length of 3 m to 54 single lenses. The gain parameter has been significantly improved compared to the previous lenses due to higher transmission, but the focused beam size and its gain are not as good as expected, mostly due to the aberrations caused by the lens shape imperfections.

  9. Possible application of compound Fresnel lens for neutron beam focusing

    International Nuclear Information System (INIS)

    We have developed a Fresnel-type focusing device for cold neutrons fabricated using single crystals of magnesium fluoride. This stacked-lens device using 50 elements (with 50 beam-bending interfaces) demonstrated a focal length of 5 m with a good transmission of 0.829 for 1.14 nm neutrons. The focused beam was 5 times more intense than a beam of the same spot size with the same final flight path length produced with the traditional pinhole collimation. The background-scattering noise from lens was an order of magnitude larger than that of the traditional pinhole collimation in the momentum range of 0.01-0.05 nm-1, almost 10-3 of focused direct beam at the lowest momentum transfers measurable. This device produced an intensity gain in measured SANS data of more than 10 times when compared with the conventional pinhole geometry with the same minimum momentum transfer

  10. Comparison of retinal image quality with spherical and customized aspheric intraocular lenses

    OpenAIRE

    Guo, Huanqing; Goncharov, Alexander V.; Dainty, Chris

    2012-01-01

    We hypothesize that an intraocular lens (IOL) with higher-order aspheric surfaces customized for an individual eye provides improved retinal image quality, despite the misalignments that accompany cataract surgery. To test this hypothesis, ray-tracing eye models were used to investigate 10 designs of mono-focal single lens IOLs with rotationally symmetric spherical, aspheric, and customized surfaces. Retinal image quality of pseudo-phakic eyes using these IOLs together with individual variati...

  11. Projection-type X-ray microscope based on a spherical compound refractive X-ray lens

    OpenAIRE

    Dudchik, Yu. I.; Gary, C. K.; Park, H; Pantell, R H; Piestrup, M. A.

    2007-01-01

    New projection- type X-ray microscope with a compound refractive lens as the optical element is presented. The microscope consists of an X-ray source that is 1-2 mm in diameter, compound X-ray lens and X-ray camera that are placed in-line to satisfy the lens formula. The lens forms an image of the X-ray source at camera sensitive plate. An object is placed between the X-ray source and the lens as close as possible to the source, and the camera shows a shadow image of the object. Spatial resol...

  12. Hard X-ray imaging by a spherical compound refractive lens

    International Nuclear Information System (INIS)

    Hard X-ray imaging by a spherical compound refractive lens is presented. The lens is composed of 123 biconcave microlenses with a size of 200 μm in diameter. Each microlens was formed by the epoxy between two bubbles, which were injected into an epoxy-filled glass capillary. The focal length of the lens is 114 mm at 8.05 keV. The light source was obtained by using a copper anode X-ray tube without a filter. The lens can be achieved a spatial resolution of 5 μm with field of view of about 700 μm, and 1-3 μm resolution may be obtainable by using monochromator and diaphragm.

  13. The generation of high precision aspherical surfaces in glass by CNC machining

    International Nuclear Information System (INIS)

    The design and production of an f/l aspheric focusing lens for a high-power laser system operating at 1054 nm is described. The relevant lens design parameters and the degree of flexibility in their choice are described and these, when carefully chosen, result in an extremely versatile lens with a large wavelength cover. The manufacture of the lens is also simplified. A comparison is made between the production of an aspheric surface by high quality conventional optical manufacturing processes and one generated and polished by a computer numerically controlled (CNC) jig grinding machine. (author)

  14. 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.

  15. MEASURING OF X-RAY SOURCE SIZE BY USING COMPOUND REFRACTIVE X-RAY LENS

    Directory of Open Access Journals (Sweden)

    Yu. V. Dudchik

    2015-04-01

    Full Text Available Compound refractive lens was used for measuring size of 2-3 beamline Standford synchrotron radiation source and a size of microfocus X-ray tube. X-ray beam from the source was focused by the lens and parameters of the beam at image plane were measured. Scanning diaphragm and X-ray CCD-camera were used for measuring X-ray beam. It was found that the vertical size of synchrotron source is equal to 0,6 mm and the size of the X-ray tube focal spot is equal to 60 micrometers. 

  16. Microscope using an x-ray tube and a bubble compound refractive lens

    International Nuclear Information System (INIS)

    We present x-ray images of grid meshes and biological material obtained using an unfiltered x-ray tube and a compound refractive lens composed of microbubbles embedded in epoxy inside a glass capillary. Images obtained using this apparatus are compared with those using a synchrotron source and the same lens. We find that the field of view is larger than that obtained using the synchrotron source, whereas the contrast and resolution are reduced. Geometrical distortion around the edges of the field of view is also reduced. The experiments demonstrate the usefulness of the apparatus in a modest laboratory setting

  17. X-ray imaging of laser produced plasmas by a compound 3D x-ray lens

    International Nuclear Information System (INIS)

    Pilot scheme for the study of plasma under extreme condition is implemented using a compound 3D X-ray lens. Hard X-ray image of laser plasma produced by irradiating of copper foil by intense laser pulse was recorded using this lens

  18. 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.

  19. Design of artificial spherical superposition compound eye

    Science.gov (United States)

    Cao, Zhaolou; Zhai, Chunjie; Wang, Keyi

    2015-12-01

    In this research, design of artificial spherical superposition compound eye is presented. The imaging system consists of three layers of lens arrays. In each channel, two lenses are designed to control the angular magnification and a field lens is added to improve the image quality and extend the field of view. Aspherical surfaces are introduced to improve the image quality. Ray tracing results demonstrate that the light from the same object point is focused at the same imaging point through different channels. Therefore the system has much higher energy efficiency than conventional spherical apposition compound eye.

  20. The use of low departure aspheric surfaces in high quality wide angle lenses

    Science.gov (United States)

    Dalzell, Kristen E.; Jonas, Reginald P.; Wallace, Brian P.

    2015-09-01

    Modern lens designs for digital sensors, such as those required in medium volumes for cinematography, often require the use of one or two high departure aspheric surfaces. With departures from best fit sphere of up to a few millimeters, the use of such surfaces are accompanied by a number of consequences: high cost metrology, very tight opto-mechanical tolerances and image artifacts due to the sub-aperture grinding and polishing process. Previously we examined the use of multiple aspheric surfaces with very low departures from best fit sphere (BFS) and concluded that advantages may be gained in standard and telephoto lenses, but not in wide angle lens designs1. In this work we consider the potential benefits of low departure aspheric surfaces, as applied to wide angle lenses in particular. We review the number, placement, and nature of aspheric surfaces in some wide angle lens design examples, and look at the potential to redesign with an increased number of low departure aspheric surfaces that have the potential to be manufactured without the need for computer generated holograms (CGH's). The use and limitations of modern interferometers capable of measuring aspheric surfaces without the use of CGH's will be considered. In one example we examine the performance, manufacturing, and cost perspective, paying particular attention to testing and mechanical alignment tolerances.

  1. A compound refractive lens for focusing high-energy X-rays

    International Nuclear Information System (INIS)

    The development of techniques for focusing X-rays has occupied physicists for more than a century. Refractive lenses, which are used extensively in visible-light optics, are generally considered inappropriate for focusing X-rays, because refraction effects are extremely small and absorption is strong. This has led to the development of alternative approaches based on bent crystals and X-ray mirrors, Fresnel and Bragg-Fresnel zone plates, and capillary optics (Kumakhov lenses). Here we describe a simple procedure for fabricating refractive lenses that are effective for focusing of X-rays in the energy range 5-40 keV. The problems associated with absorption are minimized by fabricating the lenses from low-atomic-weight materials. Refraction of X-rays by one such lens is still extremely small, but a compound lens (consisting of tens or hundreds of individual lenses arranged in a linear array) can readily focus X-rays in one or two dimensions. We have fabricated a compound lens by drilling 30 closely spaced holes (each having a radius of 0.3 mm) in an aluminium block, and we demonstrate its effectiveness by focusing a 14-keV X-ray beam to a spot size of 8 μm. (author)

  2. 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. PMID:27577759

  3. Thermal lens and all optical switching of new organometallic compound doped polyacrylamide gel

    Science.gov (United States)

    Badran, Hussain Ali

    In this work thermal lens spectrometry (TLS) is applied to investigate the thermo-optical properties of new organometallic compound containing azomethine group, Dichloro bis [2-(2-hydroxybenzylideneamino)-5-methylphenyl] telluride platinum(II), doped polyacrylamide gel using transistor-transistor logic (TTL) modulated cw 532 nm laser beam as an excitation beam modulated at 10 Hz frequency and probe beam wavelength 635 nm at 14 mW. The technique is applied to determine the thermal diffusivities, ds/dT and the linear thermal expansion coefficient of the sample. All-optical switching effects with low background and high stability are demonstrated.

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

    Directory of Open Access Journals (Sweden)

    Ladan Espandar

    2011-01-01

    Full Text Available 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 lens (IOL. The hydrophilic design of the lens is optimized to address dysphotopsia while maintaining biocompatibility, optical clarity, resistance to damage, and resistance to biocontamination. Aspheric lenses decrease postoperative spherical aberration. The addition of the Softec lens provides clinicians with another option for IOL placement; however, randomized comparative studies of this lens to others already on the market remain to be completed.Keywords: hydrophilic acrylic intraocular lens, Softec HD intraocular lens, aspheric intraocular lens, IOL

  5. The fabrication of out of plane aspherical microlens arrays

    Science.gov (United States)

    Zhang, Yong; Wang, Wanjun

    2013-03-01

    MOEMS (Micro-Opto-Elecro-Mechanical Systems) has brought new inspirations to the traditional optics design and manufacturing, due to their advantages such as micro sizes, low cost, good performance, easy to integrate, and mass production. From the microfabrication technology perspective, microlens is among the most difficult components to make, and it is also the most important component of all free space micro-optic components. In recent years, the aspherical lens with controllable curvature has become one of the most popular research subjects since it is helpful in eliminating aberration. In this paper, we report a new method of fabricating and replicating aspherical microlens array with primary optic axis in parallel with the substrate surface. The technology was based on ultra-violet (UV) lithography of SU-8 thick resist. A novel water bath oblique lithography technique was adopted. Diameter of the prototype microlenses fabricated is about 200 μm. By changing the pattern of mask and other process parameters, aspherical microlenses with different sizes and surface curvatures can be obtained. The microlens made using this technique has its main optical axis in parallel with the substrate, this makes it much easier to be integrated with other components into on-chip optical platforms such as optical switch and the imaging systems. This kind of micro-lens arrays will also be incorporated to microfluidic systems such as micro flow cytometry for fluorescence detections.

  6. Aspheric surface parameters measurement by Fizeau interferometer

    International Nuclear Information System (INIS)

    In this paper, a method for measurement the aspheric parameter by a Fizeau interferometer is presented. The aspheric surface can be a parabola, hyperbola or an ellipsoid. The main radiuse of curvature and eccentricity are the main parameters. The fringe patterns are analysed by phase shift method and the aspheric parameters are determined by fitting the aspheric function to the data. The experimental setup and measurement result will be presented.

  7. 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.

  8. Thermal lens and all optical switching of new organometallic compound doped polyacrylamide gel

    Directory of Open Access Journals (Sweden)

    Hussain Ali Badran

    2014-01-01

    Full Text Available In this work thermal lens spectrometry (TLS is applied to investigate the thermo-optical properties of new organometallic compound containing azomethine group, Dichloro bis [2-(2-hydroxybenzylideneamino-5-methylphenyl] telluride platinum(II, doped polyacrylamide gel using transistor-transistor logic (TTL modulated cw 532 nm laser beam as an excitation beam modulated at 10 Hz frequency and probe beam wavelength 635 nm at 14 mW. The technique is applied to determine the thermal diffusivities, ds/dT and the linear thermal expansion coefficient of the sample. All-optical switching effects with low background and high stability are demonstrated.

  9. Development of a low cost high precision fabrication process for glass hybrid aspherical diffractive lenses

    International Nuclear Information System (INIS)

    The hybrid aspherical diffractive singlet achromat design can be used to reduce chromatic aberration in compact optical systems. In this paper, the development of a compression molded, low cost and high precision hybrid diffractive glass lens is described. Specifically, an aspherical diffractive lens designed to compensate for chromatic aberration was fabricated by precision glass molding. The diffractive features are integrated on the aspherical surface to avoid mold alignment during fabrication. As part of the effort to lower manufacturing cost, the diffractive profiles were directly fabricated by single-point diamond turning without polishing. A thin layer of platinum–iridium coating was applied to the mold surfaces to protect the mold inserts from degradation during the molding process. In order to reduce thermal shrinkage error, the hybrid lens was fabricated using a two-step precision molding process on a commercial glass molding machine. The geometry of the molded hybrid aspherical diffractive lens was measured using an optical profilometer and the results demonstrated a match to the design mold profile with a replication error of 0.16% in the radial direction and 6.3% in the axial direction. In addition, an optical metrology system to evaluate the diffraction efficiency and chromatic focal shift was constructed and the measured results showed that the hybrid lenses indeed function as designed

  10. 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.

  11. Fast calculation of bokeh image structure in camera lenses with multiple aspheric surfaces

    Science.gov (United States)

    Sivokon, V. P.; Thorpe, M. D.

    2014-12-01

    Three different approaches to calculation of internal structure of bokeh image in camera lenses with two aspheric surfaces are analyzed and compared - the transfer function approach, the beam propagation approach and direct raytracing in an optical design software. The transfer function approach is the fastest and provides accurate results when peak-to-valley of mid-spatial frequency phase modulation induced at the lens exit pupil is below λ/10. Aspheric surfaces are shown to contribute to the bokeh structure differently increasing the complexity of bokeh image especially for offaxis bokeh.

  12. 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...

  13. Development of a compound focusing lens: improvement of signal-noise ratio

    International Nuclear Information System (INIS)

    We proposed a method to improve signal-noise ratio of the Fresnel-type neutron lens. The Gd mask of concentric circle thin layer reduced 80% noise, at the best, due to the Fresnel-type lens shape. As the transmission for 1.1 nm neutrons decreased from 0.83 to 0.79 by using the Gd mask, the loss was 0.04

  14. 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.

  15. Comparison of contrast sensitivity and wavefront analysis 8fter implantation of AcrySof IQ aspherical intraocular lens%AcrySof IQ非球面人工晶状体植入后视觉质量观察

    Institute of Scientific and Technical Information of China (English)

    罗敏; 计菁; 赵莼; 范先群; 潘燚蕾; 陆剑锋

    2009-01-01

    Objective To determine vision quality when testing two acrylic intraocular lenses,AcrySof IQ and AcrySof Natural,after routine cataract extraction and IOL implantation.Method Prospective,randomized,double-masked study that 260 eyes of 260 patients who underwent cataract extraction and IOL implantation was performed.Patients were randomly divided into 2 groups:AcrySof IQ or AcrySof Natural.One week,one and three month postoperative evaluations included contrast sensitivity and wavefront analysis.The independent-samples T test was used.P<0.05 was considered statistically significant.Result The AcrySof IQ group has significantly hisher and middle spatial frequency of contrast sensitivity.The difference in low spatial frequency was getting significant along with time.Patients with AcrySof IQ had a reduction in total high-order aberrations and spherical aberration.There were no difference in coma between two groups.Conclusion The use of aspheric acrylic AcrySof IQ IOL may improve the quality of vision as a result of the reduction of contrast sensitivity and spherical aberration.(Chin J Ophthalmol,2009,45:239-242)%目的 对比研究AcrySof IQ非球面人工晶状体和AcrySof Natural人工晶状体在年龄相关性白内障患者手术后的视觉质量.方法 前瞻性随机对照研究.选取年龄相关性白内障患者,按照双肓原则分为两组:IQ组和Natural组,分别植入AcrySof IQ和AcrySof Natural人工晶状体,其中IQ组:124只眼;Natural组:136只眼.术后观察两组患者的最佳矫正远视力、对比敏感度(CS)值、波阵面像差.采用统计软件SPSS 11.0进行数据分析,两组间术后视力采用重复测量方差分析,CS、波阵面像差采用具有一个重复测量两因素设计定量资料方差分析.结果术后1周、1个月、3个月采用CGT-1000 CS眩光测试仪检查发现两组间的CS值在中、高空间频率段均有差异(F值范围5.05~26.47,P<0.05),低频空间两组间差异随时间推移逐渐明显.

  16. A method to design aspheric spectacles for correction of high-order aberrations of human eye

    Institute of Scientific and Technical Information of China (English)

    LI Rui; WANG ZhaoQi; LIU YongJi; MU GuoGuang

    2012-01-01

    Aiming at the correction of high-order aberrations of human eye with spectacles,a design method of aspheric spectacles is proposed based on the eye's wavefront aberrations data.Regarding the eyeball and the spectacles as a whole system-the lens-eye system-the surface profiles of the spectacles are achieved by optimization procedure of lens design.Different from the conventional optometry,in which the refraction prescription is acquired with a visual chart,the design takes into account the two aspects of actual human viewing,eyeball rolling and certain distinct viewing field.The rotation angle of eyeball is set to be ±20° as wearing spectacles,and the field of view is set to be ∧7° which is especially important as watching screen display.The individual eye model is constructed as the main part of the lens-eye system.The Liou eye model is modified by sticking a thin meniscus lens to the crystalline lens.Then the defocus of the individual eye is transferred to the front surface of the meniscus lens,and the astigmatism and high-order aberrations are transferred to the front surface of the cornea.50 eyes are involved in this research,among which 36 eyes have good enough visual performance already after sphero-cylindrical correction.10 eyes have distinct improvement in vision and 4 eyes have no visual improvement by further aspheric correction.6 typical subject eyes are selected for the aberrations analysis and the spectacles design in this paper.It is shown that the validity of visual correction of aspheric lens depends on the characteristics of the eye's wavefront aberrations,and it is effective for the eye with larger astigmatism or spherical aberration.Compared with sphero-cylindrical correction only,the superiority taken by the aspheric correction is mainly on the improvement of MTF at a larger field of view.For the best aspheric correction,the MTF values increase by 18.87%,38.34%,44.36%,51.29% and 57.32% at the spatial frequencies of 40

  17. Design and realization of an aspherical doublet

    Czech Academy of Sciences Publication Activity Database

    Melich, Radek; Matela, M.; Procháska, František; Psota, Pavel; Matoušek, Ondřej; Tomka, David

    Vol. 9442. Bellingham : SPIE-INT SOC OPTICAL ENGINEERING , 2015 - (Kovačičinová, J.; Vít, T.), 94420U-94420U ISBN 978-1-62841-557-5. ISSN 0277-786X. - (SPIE). [Optics and Measurement Conference 2014 (OaM 2014). Liberec (CZ), 07.10.2014-10.10.2014] R&D Projects: GA TA ČR(CZ) TA03010843 Institutional support: RVO:61389021 Keywords : aspherical surface * asphere measurements * optical design * ZEMAX * aspherical optical production Subject RIV: JP - Industrial Processing http://spie.org/Publications/Proceedings/Paper/10.1117/12.2175915

  18. 非球面多焦点人工晶状体植入术后视觉质量的临床研究%Visual quality after aspherical multifocal intraocular lens implantation

    Institute of Scientific and Technical Information of China (English)

    李莉; 刘晶

    2012-01-01

    目的 比较2种多焦点人工晶状体IQ ReSTOR+3 D和IQ ReSTOR +4 D的临床效果.方法 选择年龄相关性白内障患者32例(41眼)行白内障超声乳化吸除联合人工晶状体植入术,其中IQ ReSTOR+3 D组15例(20眼),IQ ReSTOR +4 D组17例(21眼),比较术后3个月2组患者的远距离、中距离和近距离视力、对比敏感度、视野、离焦曲线和生活问卷调查结果.结果 术后3个月,IQ ReSTOR+3 D组裸眼中距离视力为1.38±0.06,优于IQ ReSTOR +4 D组(1.07±0.09),差异有统计学意义(P<0.05).2组间近距离和远距离视力差异均无统计学意义(均为P>0.05).离焦曲线IQ ReSTOR+3 D组在-1.5 D、-2.0 D、-2.5D的视力均优于IQ ReSTOR +4 D组,差异均有统计学意义(均为P<0.05).结论 IQ ReSTOR+3 D较IQ ReSTOR+4 D能够提供更好的中距离视力和一定距离范围的近视力.%Objective To compare the clinical effects after implantation of multi-focal lens (MIOL) between IQ ReSTOR + 3 D and IQ ReSTOR + 4 D. Methods Random clinical study of 32 patients (41 eyes) age-related cataract patients underwent phacoemulsification and IOL implantation, 15 patients (20 eyes) in IQ ReSTOR + 3 D group and 17 patients (21 eyes) in IQ ReSTOR +4 D. At 3 months after cataract surgery, the distant,intermediate and near visual acuities,contrast sensitivity,visual fields,defocus testing and questionnaires in two groups were observed. Results At postoperative 3 months, the uncorrected intermediate visual acuity of IQ ReSTOR + 3 D group was 1.38 ±0.06,which was much better than that of IQ ReSTOR+4 D group 1.07 ±0.09, there was statistical difference (P 0.05). The defocus testing showed the visual acuity at -1.5 D, -2. 0 D, -2. 5 D in IQ ReSTOR +3 D group were better than that of IQ ReSTOR + 4 D group, there were statistical differences (all P < 0.05). Conclusion The diffractive multifocal IOL with a + 3 D add power provides significantly better intermediate visual acuity and a plateau of optimum near

  19. Fabrication of compound refractive lens using soft and deep X-ray lithography beamline on Indus-2

    International Nuclear Information System (INIS)

    X-ray compound refractive lenses (CRL) have been fabricated using Soft and Deep X-ray lithography (SDXRL) beamline on Indus-2. Upto 50 parabolic lenses are fabricated in PMMA using 1X X-ray mask. The mask contains of 20 micron thick gold absorbing pattern on polyimide membrane. The lens fabrication is done by exposing 500 μm thick PMMA sheets to 5-12keV X-rays from Indus-2. The fabricated CRL will be suitable for generating focused X-ray beam of Indus-2 bending magnet source.

  20. Measuring aspheres with a chromatic Fizeau interferometer

    Science.gov (United States)

    Seifert, L.; Pruss, C.; Dörband, B.; Osten, W.

    2009-06-01

    The established method to measure aspherical surfaces is interferometric testing with null optics, but due to economical reasons the applications are limited. A special null optic has to be calculated, fabricated and qualified for each individual type of asphere. This time- and money consuming method is only cost-efficient for large quantities or when tests require high accuracy. We propose a new and flexible technique for measuring an ensemble of different aspheres with only one measurement setup. The main idea is to use the wavelength as a tunable parameter. Because it is possible to change the wavelength without introducing new errors by mechanical movements, the wavelength variation results in a higher measurement flexibility without reducing the measurement accuracy. We present the chromatic Fizeau Interferometer with a diffractive element as null-optic for the measurement of a set of four aspheres. We will show the influence of unwanted diffraction orders and the expected measurement accuracy. As in the monochromatic setup, especially the area around the optical axis is problematic and can not be measured with the desired accuracy. The use of a small aperture stop on the optical axis is recommended because errors in other radial domains are filtered as well. The results show, that the chromatic Fizeau interferometer makes the established monochromatic method far more flexible and that different aspheres can be measured in the same setup.

  1. 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.

  2. Patient acceptability of the Tecnis® multifocal intraocular lens

    OpenAIRE

    Sood, Priyanka; Woodward, Maria A.

    2011-01-01

    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....

  3. Aspherical bubble dynamics and oscillation times

    Energy Technology Data Exchange (ETDEWEB)

    Godwin, R.P.; Chapyak, E.J. [Los Alamos National Lab., NM (United States); Noack, J.; Vogel, A. [Medizinisches Laserzentrum Luebeck (Germany)

    1999-03-01

    The cavitation bubbles common in laser medicine are rarely perfectly spherical and are often located near tissue boundaries, in vessels, etc., which introduce aspherical dynamics. Here, novel features of aspherical bubble dynamics are explored. Time-resolved experimental photographs and simulations of large aspect ratio (length:diameter {approximately}20) cylindrical bubble dynamics are presented. The experiments and calculations exhibit similar dynamics. A small high-pressure cylindrical bubble initially expands radially with hardly any axial motion. Then, after reaching its maximum volume, a cylindrical bubble collapses along its long axis with relatively little radial motion. The growth-collapse period of these very aspherical bubbles differs only sightly from twice the Rayleigh collapse time for a spherical bubble with an equivalent maximum volume. This fact justifies using the temporal interval between the acoustic signals emitted upon bubble creation and collapse to estimate the maximum bubble volume. As a result, hydrophone measurements can provide an estimate of the bubble energy even for aspherical bubbles. The prolongation of the oscillation period of bubbles near solid boundaries relative to that of isolated spherical bubbles is also discussed.

  4. Deterministic finishing of aspheric optical components

    Science.gov (United States)

    Lambropoulos, Teddy; Fess, Ed; DeFisher, Scott

    2013-09-01

    Manufacturing aspheric optics can present challenges depending on the complexity of their shape. This is especially true during the finishing stage. To tackle this challenge, OptiPro Systems has developed two technologies for deterministic optical polishing: UltraForm Finishing (UFF) and UltraSmooth Finishing (USF). UFF is a deterministic sub aperture polishing process that polishes spherical, aspheric, and free form surface geometries. In contrast, the USF process is a deterministic mid to large size aperture polishing process that works with a conforming lap. These two technologies have the ability to tackle a wide range of optical shapes by removing sub-surface damage, removing various mid-spatial frequency artifacts that might be left from a grinding process, and correct the optic's figure error in a controlled fashion. This presentation will describe these technologies, present performance information as to their capabilities, and show how OptiPro is developing these technologies to push the state of the art in manufacturing.

  5. Precision grinding of micro-aspherical surface

    Science.gov (United States)

    Suzuki, Hirofumi; Shibutani, Hideo; Higuchi, Toshiro; Horiuchi, Osamu

    2003-05-01

    Recently, micro aspherical glass lenses are required for electric devices, optical devices and advanced optical fiber transmission equipments. The glass lenses are manufactured with glass molding method by using ceramics dies such as tungsten carbide and therefore molding dies are most important. The ceramics molding dies must be ground ultra-precisely with micro diamond wheel. In this report, our developed micro grinding methods/systems are discussed according to a variety of the workpiece shapes.

  6. Ductile grinding of ultraprecise aspherical optical lenses

    Science.gov (United States)

    Koenig, Wilfried; Sinhoff, Volker

    1993-04-01

    The manufacturing of glass lenses has always set exacting requirements on the finishing technique. If, in addition, the design deviates from the conventional geometry of plane and sphere, the standard manufacturing process of rough grinding with cup-wheels and subsequent precision grinding and polishing with reproductive techniques fails. In order to achieve highest form accuracies and surface qualities combined with a flexible surface shape, ductile single- point-grinding meets the requirements for the production of rotationally symmetric aspheres.

  7. A theoretical design of gradient index multifocal contact lens for correcting presbyopia and an attempt to elicit its performance using ray tracing

    Science.gov (United States)

    Bakaraju, Ravi C.; Ehrmann, Klaus; Papas, Eric B.; Ho, Arthur

    2009-02-01

    We propose a novel theoretical design of gradient index (GRIN) multifocal contact lens (MFCL) to compensate presbyopia and make predictions regarding its performance on a schematic model eye and to compare its performance with conventional aspheric progressive MFCL.

  8. REFRACTIVE NEUTRON LENS

    OpenAIRE

    Petrov, P. V.; Kolchevsky, N.N.

    2013-01-01

    Compound concave refractive lenses are used for focusing neutron beam. Investigations of spectral and focusing properties of a refractive neutron lens are presented. Resolution of the imaging system on the base of refractive neutron lenses depends on material properties and parameters of neutron source. Model of refractive neutron lens are proposed. Results of calculation diffraction resolution and focal depth of refractive neutron lens are discussed.

  9. 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...

  10. Patient acceptability of the Tecnis® multifocal intraocular lens

    OpenAIRE

    Woodward, Maria

    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...

  11. Thermal lens diagnostics and mitigation in diode end pumped lasers

    OpenAIRE

    Stučinskas, Darius

    2010-01-01

    In this thesis, analysis of thermal effects and various approaches for their mitigation in diode end pumped ultrafast lasers is presented. Experimental investigations were performed by employing Shack-Hartmann wavefront sensor which was adapted for measurements of thermal lens in diode end pumped lasers. During research, operation of high average power, diode-pumped, Nd:YVO4 laser with aspheric aberration corrector was investigated. Actual thermal lens measurements were conducted in order to ...

  12. Sub-nanometer interferometry for aspheric mirror fabrication

    International Nuclear Information System (INIS)

    Aspheric mirrors for extreme ultraviolet lithography (EUVL) at a wavelength of 13nm require surface figure accuracy approaching 0.10 nm rms. A new type of interferometry, based on the fundamental process of diffraction, is described that has the intrinsically ability to achieve this accuracy on aspherical surfaces. However, care must be taken in the design and implementation of the optical system that images the aspheric mirror onto the CCD camera. Non-common paths of the measurement and reference wavefronts within the optical system, as well as distortion of the image of aspheric mirror on the CCD, must be addressed in order to realize sub-nanometer accuracy. The phase shifting diffraction interferometer and the mitigation of potential imaging errors are described for measuring the surface figure on aspheric mirrors

  13. Novel automated process for aspheric surfaces

    Science.gov (United States)

    Bingham, Richard G.; Walker, David D.; Kim, Do-Hyung; Brooks, David; Freeman, Richard; Riley, Darren

    2000-10-01

    We report on the development of a novel industrial process, embodied in a new robotic polishing machine, for automatically grinding an polishing aspheric optics. The machine is targeted at meeting the growing demand for inexpensive axially symmetric but aspherical lenses and mirrors for industry and science, non-axisymmetric and conformal optics of many kinds, the planarization of silicon wafers and associated devices, and for controlling form and texture in other artifacts including prosthetic joints. We describe both the physics and the implementation of the process. It is based on an innovative pressurized tool of variable effective size, spun to give high removal rate. The tool traverse and orientation are orchestrated in a unique (and patented) way to avoid completely the characteristic fast peripheral-velocity and center-zero left by conventional spinning tools. The pressurized tooling supports loose abrasive grinding and polishing, plus a new bound-abrasive grinding process, providing for a wide range of work from coarse profiling to fine polishing and figuring. Finally we discuss the critical control, data handling and software challenges in the implementation of the process, contrast the approach with alternative technologies, and present preliminary results of polishing trials.

  14. The design and fabrication of common optical components lithography lens

    Science.gov (United States)

    Huang, Jiun-Woei

    2015-07-01

    The design and fabrication of common optical components lithography Lens has been carried out for a 1 to 1 stepper. The specification of lens is fulfilled the 3-D lithography system as 2 micron in resolution for 1 inch x 2.8 inches system. The lens has been sophistically designed by dual path in a triplet to reduce the number of components. A single aspherical surface has been applied to reduce the aberration to diffraction limit in lens. The well-made shapes of lens have been suggested. Then, the fabrication of lens has been in the process. Finally, the optical axis of tolerance optical mechanical mountings for lens system in assembly has been analyzed, and valuable for assembly and fabrication.

  15. Additive manufacturing of a trifocal diffractive-refractive lens

    Science.gov (United States)

    Hinze, Ulf; El-Tamer, Ayman; Doskolovich, Leonid L.; Bezus, Evgeni A.; Reiß, Stefan; Stolz, Heinrich; Guthoff, Rudolf F.; Stachs, Oliver; Chichkov, Boris

    2016-08-01

    The application of two-photon polymerization and molding for the fabrication of a multifocal diffractive-refractive lens operating in water is studied. The fabricated lens is of aspheric shape and combines diffractive and refractive parts in a single element to generate three foci. The lens performance is characterized by visualization of the beam propagation in a transparent basin filled with water containing fluorescein. The experimental measurements are in good agreement with the theoretical description. The obtained results are promising for the realization of trifocal intraocular lenses with predetermined light intensity distribution between the foci.

  16. 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...

  17. 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...

  18. 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.

  19. Refractive lens for hard x-rays

    International Nuclear Information System (INIS)

    The refractive lens for hard X-rays on the base of glass capillary is presented. The fabrication techniques for lens production are described. The model of refractive lens for hard X-ray is proposed. The model assume that the compound lens work similar one thin lens the complex refraction index of which is following: n=1-δ N + i β N. On the base of this model the parameters of focussed beam are calculated and the images of object are constructed

  20. Optimal strategy for fabrication of large aperture aspheric surfaces.

    Science.gov (United States)

    Feng, Yunpeng; Cheng, Haobo; Wang, Tan; Dong, Zhichao; Tam, Hon-Yuen

    2014-01-01

    Aspheric surfaces are widely used because of their desirable characteristics. Such a surface can obtain nearly perfect imaging quality with fewer optical elements and reduce the size and mass of optical systems. Various machine systems have been developed based on modern deterministic polishing technologies for large aperture aspheric surfaces. Several factors affect the final precision of large aperture aspheric surfaces, such as the velocity limit of the machine and the path design. Excess velocity, which will be truncated automatically by the computer numerical control system, may cause the dwell time to deviate from the desired time. When a path designed on a two-dimensional surface map with equidistant pitch is projected onto an aspheric surface, the pitch changes as a result of the varied curvature of the aspheric surface. This may affect the removal map and cause some ripple errors. A multiregion distribution strategy, which includes velocity checking, is proposed in this study to avoid exceeding the velocity limits. The strategy can be used to modify local errors and edge effects. A three-dimensional spiral path generation method is also presented using an iterative method to ensure uniformity in the space length of the adjacent circle of the spiral path. This process can reduce the ripple error caused by the overlapping of tool paths. A polishing experiment was conducted, and the results proved the validity of the proposed strategies. PMID:24514001

  1. 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 

  2. Agronomic Management under Organic Farming May Affect the Bioactive Compounds of Lentil (Lens culinaris L. and Grass Pea (Lathyrus communis L.?

    Directory of Open Access Journals (Sweden)

    Valeria Menga

    2014-02-01

    Full Text Available A two year field experiment was carried out to evaluate the effects of three row and eight row seeding on the total phenolic compound (TPC, total flavonoid content (TFC, hydrolyzed (HTC and condensed tannin (CTC, antioxidant activity (ABTS assay, protein content and soluble dietary fiber (SDF and insoluble dietary fiber (IDF in the extracts of lentil (Lens culinaris L. and grass pea (Lathyrus communis L. cultivated under organic farming. The aim of this study was to determine whether row spacing used for seeding in organic farming systems for lentil and grass pea is a suitable method to increase the accumulation of antioxidant compounds in these crops. Grass pea showed the highest mean SDF and protein while lentil varieties showed the greatest and significant content of all of the antioxidant compounds. In lentil, there were increases in TPC (52%, HTC (73%, TFC (85% and CTC (41%, passing from three rows to eight rows, while in grass pea, the increases were lower, and only significant for TFC and CTC (37%, 13% respectively. In both lentils and grass pea, the highest correlation coefficient was between TPC and HTC, which indicates that the HTC includes the predominant phenolic compounds in lentil as well as in grass pea (r = 0.98, 0.71 p < 0.001, respectively. Regardless of legume species, TPC, HTC, TFC and CTC showed significant (p < 0.001 and linear correlations with the ABTS assay. These data confirm the key role of row spacing for the improvement of the antioxidant properties of lentil in organic farming; moreover, they hint at the major responsiveness and adaptation of lentil to environmental stimulus with respect to grass pea.

  3. Polishing of S-FPL-53 Aspherical Lenses

    Czech Academy of Sciences Publication Activity Database

    Poláková, Ivana; Procháska, František; Klepetková, Eva

    Vol. 9442. Bellingham : SPIE-INT SOC OPTICAL ENGINEERING , 2015 - (Kovačičinová, J.; Vít, T.), s. 944213-944213 ISBN 978-1-62841-557-5. ISSN 0277-786X. - (SPIE). [Optics and Measurement Conference 2014 (OaM 2014). Liberec (CZ), 07.10.2014-10.10.2014] R&D Projects: GA MŠk(CZ) LO1206 Institutional support: RVO:61389021 Keywords : polishing * asphere * S-FPL-53 * aspherical surface Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass http://dx.doi.org/10.1117/12.2178126

  4. Metrology for the production process of aspheric lenses

    Science.gov (United States)

    Beutler, Andreas

    2016-06-01

    Metrology revealing the form deviation of an aspheric surface is a fundamental part of all different production processes of aspheric lenses. Different processing steps have different requirements for the production. A selection of measuring instruments commonly applied in these processes is presented. This contains tactile and optical pointwise measuring instruments and laser interferometer systems. The principle functionality and the properties are presented. An overview of the application of these systems in different production processes is given. In order to show comparability, measuring results of the different types of systems are presented.

  5. Computer numeric control subaperture aspheric surface polishing—microroughness evaluation

    Czech Academy of Sciences Publication Activity Database

    Procháska, František; Polák, Jaroslav; Matoušek, O.; Tomka, David

    2014-01-01

    Roč. 53, č. 9 (2014), 092011-092011. ISSN 0091-3286 R&D Projects: GA MŠk(CZ) ED2.1.00/03.0079 Institutional support: RVO:61389021 Keywords : aspheric polishing * optic surface microroughness evaluation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.954, year: 2014 http://opticalengineering.spiedigitallibrary.org/article.aspx?articleid=1901511

  6. A New Locus Shaping Method of Quadric Aspheric Parts

    Institute of Scientific and Technical Information of China (English)

    WANG Yuan-sheng; WANG He-yan; LU Gui-ying; CAI Li; PIAO Cheng-gao

    2005-01-01

    The original idea and shaping principle of locus shaping method for processing the aspheric optical parts are introduced, and the partial structure of the machine tool designed is described. The method has the advantage of high efficiency and low cost compared to the numerical control method. And it is proven that the method is feasible.

  7. Preparation of Core-Shell Hybrid Compounds by Atomic Transfer Radical Polymerization and Its Application to Plastic Lens of Headlamp.

    Science.gov (United States)

    Noh, Seung-Man; Ahn, Jae-Beum; Choi, Ki-Hyun; Park, Seung-Kyu

    2015-09-01

    Nano silica ball (NSB) core polymethylmethacrylate (PMMA) shell hybrid nanocomposites were synthesized by atomic transfer radical polymerization (ATRP) method for the application to the clearcoat to enhance scratch resistance. The characteristics of the synthesized inorganic/organic hybrid material were examined by scanning electron microscope (SEM), particle size analysis, Fourier transform infrared (FTIR) spectroscopy and thermo gravimetric analysis-differential scanning calorimetry (TGA-DSC). The scratch resistance and light transmittance of the clearcoat were measured by a nano-scratch tester and UV-visible spectroscopy, respectively. The average particle size of the NSB-PMMA hybrid compounds was 30 nm with narrow size distribution. Even 0.1 wt% loading of NSB-PMMA in the clearcoat dramatically enhanced the scratch resistance, about 40% increase in the force of the first fracture, while slightly reduced the light transmittance, about 5% only. PMID:26716303

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yonghui; Wei, Tongbo, E-mail: tbwei@semi.ac.cn; Xiong, Zhuo; Shang, Liang; Tian, Yingdong; Zhao, Yun; Zhou, Pengyu; Wang, Junxi; Li, Jinmin [Semiconductor Lighting Technology Research and Development Center, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2014-07-07

    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.

  9. Fresnel Lens

    Science.gov (United States)

    Watson, Michael D.; Scott, Steve; Lamb, David; Zimmerman, Joe E. (Technical Monitor)

    2001-01-01

    Fresnel lenses span the full range of sizes from lens a few micrometers in diameter to lens several meters in diameter. These lenses are utilized in various fields including optical communication, theatrical lighting, office equipment, video entertainment systems, solar concentrators, and scientific research instruments. These lenses function either as diffractive or refractive optical elements depending on the geometrical feature size of the lens. The basic functions of these lenses is described followed by an overview of fabrication methods. A summary of applications is then provided illustrating the rich variety of applications for which fresnel lenses may be designed to fulfill.

  10. Use of very low departure aspheric surfaces in high quality camera lenses

    Science.gov (United States)

    Dalzell, Kristen E.; Jonas, Reginald P.; Thorpe, Michael D.

    2014-12-01

    High performance, compact cinematography lenses working over a large sensor area are demanding designs which are achieved using one or two high departure aspheric elements. With sag departures from best fit sphere of up to a few millimeters, the use of such aspheres is accompanied by a number of consequences. These include high cost metrology, very tight opto-mechanical tolerances and the potential for image artifacts produced during the sub-aperture grinding and polishing process. A modified asphere manufacturing process was utilized to reduce artifacts by eliminating the subaperture grinding and pre-polishing. This method is limited to aspheric surfaces which can be directly polished from a spherical base surface with aspheric departures of <15μm. These very low departure aspheres have the benefit of inexpensive metrology and tolerance relaxation compared with high departure aspheres. Interferograms, slope maps, and out-of-focus images demonstrate the feasibility and advantages of direct asphere generation from a polished sphere. A series of large format lenses covering focal lengths from telephoto to wide angle, were redesigned to determine the feasibility of the use of very low departure aspheres. Increasing the number of aspheric surfaces but reducing the aspheric departure to less than 15μm was demonstrated. We conclude that 3-5 very low departure aspheres are sufficient to provide similar performance to the high departure asphere designs for most focal lengths. One limitation encountered was in the wide angle lenses. The exception was the wide angle lenses where it is difficult to reduce departures below 30μm while maintaining the same optical performance.

  11. Outdoor overall performance of a novel air-gap-lens-walled compound parabolic concentrator (ALCPC) incorporated with photovoltaic/thermal system

    International Nuclear Information System (INIS)

    Highlights: • A prototype of an ALCPC-PV/T system was designed and set up. • Good optical agreements were observed between simulation and experiment. • The effects of the temperature on the electrical characteristics were discussed. • The thermal performance for circulating cooling was analyzed. • The system efficiency was calculated to present the overall performance. - Abstract: A novel air-gap-lens-walled compound parabolic concentrator incorporated with photovoltaic/thermal system (ALCPC-PV/T) was proposed. The optical, electrical and thermal performances of the ALCPC-PV/T under the outdoor condition were analyzed for building integrated concentrating photovoltaic/thermal application. The simulation and experiment were carried out to reveal the optical characteristics of ALCPC-PV/T on two typical days. The experiment results verified the optical simulation results that the ALCPC-PV/T system had a half acceptance angle of 35° and an average optical efficiency of 83.0% within the half acceptance angle for direct incidence. Furthermore, the average optical efficiencies on the two typical days were all above 60% under the actual outdoor condition considering direct and diffuse solar radiation. Details of electrical characteristics affected by the temperature of circulating cooling water were also displayed. The electrical and thermal efficiencies of the ALCPC-PV/T system during the test were 6.0% and 35.0% respectively with the final water temperature of 70 °C. In addition, the fitted results indicated that under the zero reduced temperature condition, the thermal efficiency of the ALCPC PV/T system was 52.0%, and the corresponding electrical efficiency was 6.6%

  12. Lens customization method to minimize aberration in integral imaging

    Science.gov (United States)

    Miranda, Matheus; Kim, Jonghyun; Hong, Keehoon; Lee, Byoungho

    2015-10-01

    Conventionally the elemental lenses of the lens-array used in integral imaging have spherical surface profiles, thus they suffer from intrinsic lens aberrations such as spherical aberration and astigmatism. Aberrations affect the ability of the lens to focus light in a single point, or to collimate light from a point source. In integral imaging, this results in a loss of image quality of the reconstructed image due to distortions. The viewing characteristics of the integral imaging system, such as viewing angle and image resolution, are also affected by aberrations. We propose the use of a custom made aspherical lens-array which was specifically designed to minimize distortions due to aberrations and hence improve the reconstructed image quality. Ray optics calculations are used in order to analyze the aberrations and find the initial lens surface profile. Lens optimization is performed with the aid of numerical simulation software. The designed lens-array is compared to a conventional spherical lens-array of same properties. The design, optimization, and fabrication processes are described and the experiments are presented and compared with the computer simulations.

  13. Manufacturing of high-precision aspherical and freeform optics

    Science.gov (United States)

    Hoogstrate, André M.; van Drunen, Casper; van Venrooy, Bart; Henselmans, Rens

    2012-09-01

    Aspherical and freeform optical elements have a large potential in reducing optical aberrations and to reduce the number of elements in complex high performance optical systems. However, manufacturing a single piece or a small series of aspherical and freeform optics has for long been limited by the lack of flexible metrology tools. With the cooperative development of the NANOMEFOS metrology tool by TNO, TU/e and VSL, we are able to measure the form of aspheres and freeforms up to 500 mm in diameter with an accuracy better than 10 nm rms. This development opened the possibility to exploit a number of iterative, corrective manufacturing chains in which manufacturing technologies such as Single Point Diamond Turning, freeform grinding, deterministic polishing and classical polishing are combined in an iterative loop with metrology tools to measure form deviation (like CMM, LVDT contact measurement, interferometry and NANOMEFOS). This paper discusses the potentials, limitations and differences of iterative manufacturing chains used by TNO in the manufacturing of high performance optics for astronomical purposes such as the anufacturing of the L2 of the Optical Tube Assembly of the four laser-guide star facility of the ESO VLT, Manufacturing of Aluminium freeforms mirrors for the SCUBA-2 instrument. Based on these results we will give an outlook into the new challenges and solutions in manufacturing high-precision optics.

  14. 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.

  15. Simulation analysis of grinding wheel motion trajectory on SiC ceramics aspheric surface grinding

    Science.gov (United States)

    Zhang, Feihu; Liu, Lifei; Li, Chunhui

    2014-08-01

    In grinding process of SiC ceramics aspheric surface, the motion trajectory of grinding wheel has great influence on the surface forming. The paper provides mathematical models of grinding wheel movements; analytical simulation was done to describe the trajectories of the grinding wheel in manufacturing an aspherical workpiece. The effect of grinding parameters (including the rotation speed of the workpiece, the feed rate of grinding wheel etc.) on the aspheric surface coverage rate was conducted and discussed in detail. An experimental study was done according to the simulation results and an aspheric surface with form error less than 10μm was gained.

  16. 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 the...

  17. 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.

  18. Asphericity of the human cornea for different corneal diameters

    OpenAIRE

    González-Méijome, José Manuel; Villa-Collar, César; Montés-Micó, Robert; Gomes, Antonio

    2007-01-01

    PURPOSE: To measure the anterior corneal asphericity (Q) with different corneal diameters. SETTING: Department of Physics (Optometry), University of Minho, Braga, Portugal. METHODS: Thirty-six eyes of 36 patients were evaluated using a videokeratoscope, and the Q-values were recorded. Topographic data were also analyzed using Vol-CT 6.89 software (Sarver & Associates, Inc) to obtain the Q-values with different corneal diameters (3.0 mm, 4.0 mm, 5.0 mm, 6.0 mm, and 7.0 mm). Variable Q models o...

  19. Research on process technology of off-axis ellipsoid aspheric mirror

    Science.gov (United States)

    Liu, Dongmei; Ma, Ke; Jia, Zonghe

    2015-02-01

    In recent years, the off-axis aspheric surface is widely used in wide coverage and high-resolution space optical systems. In this paper, research on processing technology of high precision and high efficiency off-axis ellipsoid aspheric mirror was studied deeply. With the help of CNC milling and polishing machine, off-axis ellipsoid aspheric mirror with diameter of 58mm was developed, by optimizing the concentration of polish liquid, grinding size, machining direction and other process parameters, based on the disadvantage of traditional processing that off-axis aspheric is easy to generate edge splitting and secondary surface damage, a new processing method "vertical off-axis ellipsoid aspheric surface processing method" was put forward. This method not only ensures the accuracy of work piece of optical axis, surface accuracy and accuracy of the edge, but also reduces secondary surface damage, improves processing efficiency and achieves high precision and high efficiency processing of off-axis ellipsoid aspheric surface, which is conducive to mass production. Through the detection of off-axis ellipsoid aspheric mirror by Taylor Profiler , surface accuracy (PV value) is 0.1981μm, the aspheric surface finish is level II and the optical axis accuracy is 0.01mm that it meets the requirements.

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

    OpenAIRE

    Meyer B; Sluyterman van Langeweyde G; Wottke M

    2015-01-01

    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: Retrospect...

  1. High numerical aperture silicon collimating lens for mid-infrared quantum cascade lasers manufactured using wafer-level techniques

    OpenAIRE

    Logean, Eric; Hvozdara, Lubos; Di Francesco, Joab; Herzig, Hans Peter; Voelkel, Reinhard; Eisner, Martin; Baroni, Pierre-Yves; Rochat, Michel; Müller, Antoine

    2012-01-01

    We present an aspheric collimating lens for mid-infrared (4-14 µ) quantum cascade lasers. The lenses were etched into silicon by an inductively coupled plasma reactive ion etching system on wafer level. The high refractive index of silicon reduces the height of the lens prole resulting in a simple element working at high numerical aperture (up to 0.82). Wafer level processes enable the fabrication of about 5000 lenses in parallel. Such cost-eective collimating lens is a step towards the adopt...

  2. High precision metrology of domes and aspheric optics

    Science.gov (United States)

    Murphy, Paul E.; Fleig, Jon; Forbes, Greg; Tricard, Marc

    2005-05-01

    Many defense systems have a critical need for high-precision, complex optics. However, fabrication of high quality, advanced optics is often seriously hampered by the lack of accurate and affordable metrology. QED's Subaperture Stitching Interferometer (SSI®) provides a breakthrough technology, enabling the automatic capture of precise metrology data for large and/or strongly curved (concave and convex) parts. QED"s SSI complements next-generation finishing technologies, such as Magnetorheological Finishing (MRF®), by extending the effective aperture, accuracy and dynamic range of a phase-shifting interferometer. This workstation performs automated sub-aperture stitching measurements of spheres, flats, and mild aspheres. It combines a six-axis precision stage system, a commercial Fizeau interferometer, and specially developed software that automates measurement design, data acquisition, and the reconstruction of the full-aperture figure error map. Aside from the correction of sub-aperture placement errors (such as tilts, optical power, and registration effects), our software also accounts for reference-wave error, distortion and other aberrations in the interferometer"s imaging optics. The SSI can automatically measure the full aperture of high numerical aperture surfaces (such as domes) to interferometric accuracy. The SSI extends the usability of a phase measuring interferometer and allows users with minimal training to produce full-aperture measurements of otherwise untestable parts. Work continues to extend this technology to measure aspheric shapes without the use of dedicated null optics. This SSI technology will be described, sample measurement results shown, and various manufacturing applications discussed.

  3. Systematic uncertainties from halo asphericity in dark matter searches

    International Nuclear Information System (INIS)

    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 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

  4. Decentration of a spectacle lens

    Science.gov (United States)

    Bartkowska, Janina

    1998-10-01

    The correct placing of the lenses plays an important role in the ophthalmological practice. Centering errors cause disadvantageous prismatic effects and worsen image quality. The optical axes of the spectacles should pass by rotation centers of the eyes. An often met error consists in a faulty center distance, in a wrong positioning of the lenses axis or their placing too high, too low, or in the inclining without lowering. The errors reach some millimeters and some degrees of arc. In technical optics acceptable errors are fractions or hundredths of millimeters and minutes or seconds of arc. Therefore only first powers of decentration are taken into account. In the spectacle optics one cannot omit the second powers of decentration vector. An astigmatism proportional to the square of decentration arises in the center of the field. The off axis aberrations are a quadratic function of the decentration with linear term. The aberrations are calculated by admitting a virtual diaphragm in the point of intersection of the lens axis with the eye's view axis. This method can be applied also to the lenses with aspheric surface and to astigmatic lenses, if the decentration vector lies in one of the principal sections of toroidal surface.

  5. Optical design of an aspherical cylinder-type reflecting solar concentrator

    International Nuclear Information System (INIS)

    In this paper a highly efficient solar concentrating mirror is presented. A part of the aspherical cylinder's inner wall defined by a set of specific coefficients a2, a4, a6, a8, a10, a12, a14, a16 and C is used as reflective surfaces of concentrating mirror. Based on the particular aspherical equation and the optical law of reflection, the relationship between the direction vectors of the sunlight beams reflected from the cylindrical inner wall and the coefficients of an aspherical equation, a2, a4, a6, a8, a10, a12, a14, a16 and C has been derived. By optimizing these coefficients, the Sunbeams incident on the aspherical cylinder's inner wall can be focused on a very narrow line segment parallel to the cylindrical busbar and form a linear focus (focal line). The particular set of coefficients associated with the particular aspherical equation is obtained by using particle swarm optimization algorithm. The focusing effect of the solar concentrating mirror with respect to the particular set of coefficients is demonstrated by using computer simulations and the experiment. The theoretical results show that this solar concentrating mirror has a light compression ratio of about 285 to 1. The linear spot can be used as a strong light source or a high temperature heat source. - Highlights: • A part of the aspherical cylinder's inner wall is used as a concentrating mirror. • The relationship between direction vectors of reflected Sunbeams and aspheric coefficients. • The particular set of aspheric coefficients obtained with particle swarm optimization algorithm. • The Sunbeams can be focused on a very narrow line segment parallel to the cylindrical busbar. • The aspheric cylindrical concentrating mirror has a light compression ratio of 285 to 1

  6. Chromatic aberration elimination for digital rear projection television L-type lens by genetic algorithms

    Science.gov (United States)

    Fang, Yi-Chin; Liu, Tung-Kuan; Wu, Bo-Wen; Chou, Jyh-Horng; MacDonald, John

    2008-05-01

    Following the development of a digitalized image optics system, chromatic aberration has become increasingly important especially in lateral color aberration. For rear projection television L-type lens, chromatic aberration plays the significant role because it is easily seen when facing bright screen. Basically, the elimination of axial chromatic and lateral color aberration for an optical lens depends on the choice of optical glass. DLS (damped least squares), a Ray-tracing-based method, is limited, owing to its inability to identify an enhanced optical system configuration. Genetic algorithms were applied to so-called global optimization but unfortunately so far the results show little success. Additionally, L-type optics with aspherical surface might complicate optimization due to being nonlinear response during optimization. As an alternative, this research proposes a new feasible chromatic aberration optimization process by using algorithms involving theories of geometric optics in a lens, real encoding, multiple dynamic crossover and random gene mutation techniques. In this research, rear projection television lens with aspherical surface and L-type lens are mainly discussed. Results and conclusions show that attempts to eliminate difficult axial and lateral color aberration are successful.

  7. 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...

  8. 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.

  9. 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...

  10. The Effect of the Asphericity of Myopic Laser Ablation Profiles on the Induction of Wavefront Aberrations

    OpenAIRE

    Bühren, Jens; Nagy, Lana; Yoon, Geunyoung; MacRae, Scott; Kohnen, Thomas; Huxlin, Krystel R.

    2010-01-01

    A PMMA model study showed that spherical aberration induction in laser refractive surgery is due to loss of ablation efficiency in the corneal periphery. Aspheric ablation induced less spherical aberration and provided better theoretical image quality.

  11. 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,...

  12. Research on geometric model of grinding large and medium scales optical aspheric surfaces

    Science.gov (United States)

    Kang, Nianhui; Li, Shengyi; Zheng, Ziwen

    2006-01-01

    Aspheric optics have been used in optical systems widely because of their excellent optical properties. At present, the manufacture of small scale aspheric surfaces has been industrialized. However the manufacture of large and medium aspheric surfaces still follows the procedure of grinding, lapping and polishing. Generally speaking, increasing the working efficiency is the key of machining large and medium scale aspheric surfaces. As we know, lapping and polishing have relatively low efficiencies. Therefore prior to lapping and polishing, NC grinding is often used to shape large and medium scale optical aspheric surfaces, so as to reduce the subsequent process time. Current approaches to grinding aspheric surfaces differ from each other because the wheels and methods used are different, which is inconvenient for programming. To facilitate programming, a unified mathematical formulation is proposed for calculation of the wheel center trajectory when grinding axisymmetric aspheric surfaces based on the principle of shaping aspheric surfaces. Certain geometric models are derived from the unified formulation for the cases of parallel grinding wheel, spherical grinding wheel and cup grinding wheel, according to their features of process. The condition of avoiding overcutting is also derived. The step length of cutting is adaptively selected with accuracy control so as to reduce the program codes. After analyze all the factors affecting the shape accuracy of the curved surface, the major factors are found to be the tool setting error and the radius error of the grinding wheel, then the corresponding influence coefficients of the errors are calculated and the simulation results are given. Finally an example is shown in order to prove the analysis.

  13. 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.

  14. Research on precision grinding processing and compensation finishing experiment for mid-large- aperture square aspheric optical element

    Science.gov (United States)

    Nie, Fengming; Li, Zhanguo; Wang, Dasen; Zhang, Guangping; Guo, Chengjun; Pei, Ning; Li, Yupeng

    2014-08-01

    This paper analyzes dot-line envelope grinding principle, which is applicable to mid-large- aperture square aspheric optical element, determines the mathematical process control model based on X/Y/C three-axis aspheric grinding machine, We develop the appropriate high-precision aspheric grinding manufacturing and measurement systems software, using the plane grinding wheel to do the grinding experiments and the repeated compensation processing experiment. The experiments show that: high-precision aspheric grinding manufacturing and measurement systems software can be realized axisymmetric aspheric high-precision machining control and measurement; using compensation processing of the X/Y/C three-axis aspheric grinding machine which can effectively improve the precision PV value, surface error from the initial processing of the PV value :12 μm to the compensation processing of the PV value :3 μm .

  15. Accommodating volume-constant age-dependent optical (AVOCADO) model of the crystalline GRIN lens.

    Science.gov (United States)

    Sheil, Conor J; Goncharov, Alexander V

    2016-05-01

    The purpose of this manuscript is to introduce a new age-dependent model of the human lens with two GRIN power distributions (axial and radial) that allow decoupling of its refractive power and axial optical path length. The aspect ratio of the lens core can be held constant under accommodation, as well as the lens volume by varying the asphericity of the lens external surfaces. The spherical aberration calculated by exact raytracing is shown to be in line with experimental data. The proposed model is compared to previous GRIN models from the literature, and it is concluded that the features of the new model will be useful for GRIN reconstruction in future experimental studies; in particular, studies of the accommodation-dependent properties of the ageing human eye. A proposed logarithmic model of the lens core enables decoupling of three fundamental optical characteristics of the lens, namely axial optical path length, optical power and third-order spherical aberration, without changing the external shape of the lens. Conversely, the near-surface GRIN structure conforms to the external shape of the lens, which is necessary for accommodation modelling. PMID:27231637

  16. Asphericity and clumpiness in the winds of Luminous Blue Variables

    CERN Document Server

    Davies, B; Vink, J S; Davies, Ben; Oudmaijer, Rene D.; Vink, Jorick S.

    2005-01-01

    We present the first systematic spectropolarimetric study of Luminous Blue Variables (LBVs) in the Galaxy and the Magellanic Clouds, in order to investigate the geometries of their winds. We find that at least half of our sample show changes in polarization across the strong H$\\alpha$ emission line, indicating that the light from the stars is intrinsically polarized and therefore that asphericity already exists at the base of the wind. Multi-epoch spectropolarimetry on four targets reveals variability in their intrinsic polarization. Three of these, AG Car, HR Car and P Cyg, show a position angle (PA) of polarization which appears random with time. Such behaviour can be explained by the presence of strong wind-inhomogeneities, or `clumps' within the wind. Only one star, R 127, shows variability at a constant PA, and hence evidence for axi-symmetry as well as clumpiness. However, if viewed at low inclination, and at limited temporal sampling, such a wind would produce a seemingly random polarization of the typ...

  17. Grinding aspheric and freeform micro-optical molds

    Science.gov (United States)

    Tohme, Yazid E.

    2007-02-01

    Fueled by the need for better performing optics, glass optics are now replacing plastic optics in many industrial and consumer electronic devices. One of these devices is the mobile phone camera. The optical sub-assembly in a mobile phone includes several micro lenses that are spherical and/or aspherical in shape and require form tolerances in the submicron range. These micro glass lenses are mass produced by a replication process known as glass press molding. The process entails the compression of a glass gob between two precise optical quality molds at an elevated temperature, usually near the transition temperature of the glass material. The elevated forces and temperatures required in the glass molding process limits the materials of the molds to very tough materials such as tungsten carbide or silicon carbide. These materials can withstand large pressing forces at high temperatures without any significant deformation. These materials offer great mechanical properties for glass press molding but they are also a challenge to machine to submicron accuracy. The work in this paper discusses a deterministic micro grinding manufacturing process referred to as wheel normal grinding, which is utilized to produce these optical quality molds. Wheel normal grinding is more accurate and more deterministic than most other grinding techniques and can produce molds to the form and finish tolerances required for optical molding. This method relies on the ability to recognize and compensate for grinding wheel wear and machine repeatable errors. Results will be presented to illustrate the accuracy of this micro grinding technique.

  18. Use of a NOM profilometer to measure large aspheric surfaces

    Science.gov (United States)

    Pearson, John L.; Roberts, Gareth W.; Rees, Paul C. T.; Thompson, Samantha J.

    2015-09-01

    The use of autocollimator-based profilometers of the Nanometer Optical measuring Machine (NOM) design has been reported for the evaluation of X-ray optics for some time. We report a related development in the use of a non-contact NOM profilometer for the in situ measurement of base radius of curvature and conic constant for E-ELT primary mirror segments during fabrication. The instrument is unusual in NOM design in that it is deployable onto a CNC polishing machine in an industrial fabrication environment. Whilst the measurement of radius of curvature of spherical surfaces over a single scan has been reported previously, here we report on the use of this instrument to measure optical surfaces with an aspheric departure of 180 micrometers using a grid of multiple scans and bespoke surface fitting software. The repeatability of the measurement has been found to be approximately 1 mm in a measured radius of curvature of approximately 90 m. The absolute accuracy is limited by the accuracy of the calibration of the autocollimator and the in situ calibration of the instrument during operation.

  19. Comparison of contact and non-contact asphere surface metrology devices

    Science.gov (United States)

    DeFisher, Scott; Fess, Edward M.

    2013-09-01

    Metrology of asphere surfaces is critical in the precision optics industry. Surface metrology serves as feedback into deterministic grinding and polishing platforms. Many different techniques and devices are used to qualify an asphere surface during fabrication. A contact profilometer is one of the most common measurement technologies used in asphere manufacturing. A profilometer uses a fine stylus to drag a diamond or ruby tip over the surface, resulting in a high resolution curved profile. Coordinate measuring machines (CMM) apply a similar concept by touching the optic with a ruby or silicon carbine sphere. A CMM is able to move in three dimensions while collecting data points along the asphere surface. Optical interferometers use a helium-neon laser with transmission spheres to compare a reflected wavefront from an asphere surface to a reference spherical wavefront. Large departure aspheres can be measured when a computer generated hologram (CGH) is introduced between the interferometer and the optic. OptiPro Systems has developed a non-contact CMM called UltraSurf. It utilizes a single point non-contact sensor, and high accuracy air bearings. Several different commercial non-contact sensors have been integrated, allowing for the flexibility to measure a variety of surfaces and materials. Metrology of a sphere and an asphere using a profilometer, CMM, Interferometer with a CGH, and the UltraSurf will be presented. Cross-correlation of the measured surface error magnitude and shape will be demonstrated. Comparisons between the techniques and devices will be also presented with attention to accuracy, repeatability, and overall measurement time.

  20. Non-contact optical measurement of lens capsule thickness during simulated accommodation

    Science.gov (United States)

    Ziebarth, Noel; Manns, Fabrice; Acosta, Ana-Carolina; Parel, Jean-Marie

    2005-04-01

    Purpose: To non-invasively measure the thickness of the anterior and posterior lens capsule, and to determine if it significantly changes during accommodation. Methods: Anterior and posterior capsule thickness was measured on post-mortem lenses using a non-contact optical system using a focus-detection technique. The optical system uses a 670nm laser beam delivered to a single-mode fiber coupler. The output of the fiber coupler is focused on the tissue surface using an aspheric lens (NA=0.68) mounted on a translation stage with a motorized actuator. Light reflected from the sample surface is collected by the fiber coupler and sent to a photoreceiver connected to a computer-controlled data acquisition system. Optical intensity peaks are detected when the aspheric lens is focused on the capsule boundaries. The capsule thickness is equal to the distance traveled between two peaks multiplied by the capsule refractive index. Anterior and posterior lens capsule thickness measurements were performed on 18 cynomolgus (age average: 6+/-1 years, range: 4-7 years) eyes, 1 rhesus (age: 2 years) eye, and 12 human (age average: 65+/-16, range: 47-92) eyes during simulated accommodation. The mounted sample was placed under the focusing objective of the optical system so that the light was incident on the center pole. Measurements were taken of the anterior lens capsule in the unstretched and the stretched 5mm states. The lens was flipped, and the same procedure was performed for the posterior lens capsule. Results: The precision of the optical system was determined to be +/-0.5um. The resolution is 4um and the sensitivity is 52dB. The human anterior lens capsule thickness was 6.0+/-1.2um unstretched and 4.9+/-0.9um stretched (p=0.008). The human posterior lens capsule was 5.7+/-1.2um unstretched and 5.7+/-1.4um stretched (p=0.974). The monkey anterior lens capsule thickness was 5.9+/-1.9um unstretched and 4.8+/-1.0um stretched (p=0.002). The monkey posterior lens capsule was 5

  1. Contact Lens Solution Toxicity

    Science.gov (United States)

    ... rash and rashes clinical tools newsletter | contact Share | Contact Lens Solution Toxicity Information for adults A A A This image shows a reaction to contact lens solution. The prominent blood vessels and redness ...

  2. Research on complex grinding and lapping of micro-aspheric surface

    Science.gov (United States)

    Guo, Yinbiao; Lin, Feilong

    2006-02-01

    Aiming at several problems existing in micro-aspheric component manufacture field in china recently, this paper brings forward a new complex grinding and lapping method that is used in producing micro-aspheric optical workpiece. This method adopts a complex wheel which integrates micro-grinding and MRF technique. The structure and parameters of the new pattern-grinding wheel are analyzed. The course of processing is summarized and every steps of controlling system are introduced. Methods about solving technical difficulties of process are put forward. The new complex processing method can increase flexility, processing efficiency and precision of the manufacture system, and provide a feasible way to resolve shortages of the micro-aspheric component manufacture domain.

  3. Ultraprecision finishing of micro-aspherical surface by ultrasonic assisted polishing; Technical Digest

    Science.gov (United States)

    Suzuki, Hirofumi; Kawamori, Ryota; Yamamoto, Yuji; Miyabara, Mitsuru; Okino, Tadashi; Hijikata, Yoshio; Moriwaki, Toshimichi

    2005-05-01

    Micro aspherical glass lenses are required for electronic devices, optical devices and advanced optical fiber transmission equipments. The glass lenses are manufactured by glass molding method by using micro ceramics dies such as tungsten carbide or silicon carbide (1). Therefore molding dies are most important and they were ground by ultra-precision grinding method with diamond wheel. Recently, the wavelength of used laser is becoming shorter and then the accuracies of the micro molding die are required to be much more precise (2). In this paper, ultrasonic assisted polishing methods/systems were developed in order to finish micro aspherical dies that were ground with micro diamond wheel. In the polishing experiments, the molding die of tungsten carbide was polished with diamond abrasives to test the basic polishing characteristics and the aspheric die was polished with proposed ultrasonic assisted polishing method.

  4. Design of aspherical surfaces for panoramic imagers using multi-populations genetic algorithm

    Science.gov (United States)

    Wang, Li-Ping; Liang, Zhong-zhu; Jin, Chun-Shui

    2009-05-01

    A design method of aspherical surface for panoramic imaging system with two mirrors using multi-populations genetic algorithms is proposed. Astigmatism induced by mirrors may significantly compromise image resolution. To solve this problem, we induced algebraic expression of astigmatism in panoramic imager based on generalized Coddington equation and theory of geometric optics. Then, we propose an optimization process for mirror profile design to eliminate astigmatism and provide purposely-designed projection formula with aid of MPGA. A series of polynomial expressions of aspherical surfaces are obtained and procedures of the design are presented. In order to facilitate ray tracing and aberration calculation, even asphere surface model is obtained by using of hybrid schemes combining MPGA and damped least squares. Finally, a prototype of the catadioptric panoramic imager has been developed and panoramic ring image is obtained.

  5. Scanning pupil approach to aspheric surface slope error tolerancing in head-up display optics

    Science.gov (United States)

    Sivokon, V. P.

    2015-09-01

    We present a novel approach to tolerancing slope errors of aspheric surfaces in relay optics of typical avionics head-up displays (HUD). In these systems, a beamlet entering the pilot eye occupies only a tiny fraction of HUD entrance pupil/eyebox with a typical diameter of 125mm. Consequently the beam footprint on any HUD optical surface is a small fraction of its clear aperture. This presents challenges to HUD tolerancing which is typically based on parallax (angular difference in line of sight between left and right eyes) analysis. Aspheric surfaces manufactured by sub-aperture grinding/polishing techniques add another source of error - surface slope error. This type of error not only degrades image quality of observed HUD symbology but also leads to its "waviness" and "floating" especially noticeable when a pilot moves his head within the HUD eyebox. The suggested approach allows aspheric surface slope error tolerancing that ensures an acceptable level of symbology "waviness". A narrow beamlet is traced from a pilot eye position backwards through the HUD optics until it hits the light source. Due to the small beamlet size, slope error of the aspheric surface acts primarily as an overall tilt/wedge that deviates the beam and causes it to shift. The slope error is acceptable when this shift is not resolved by a pilot eye. The beamlet is scanned over entire eyebox and field of view and the slope error tolerance is established for several zones in the aspheric surface clear aperture. The procedure is then repeated for each aspheric surface.

  6. LensClean revisited

    CERN Document Server

    Wucknitz, O

    2004-01-01

    We discuss the LensClean algorithm which for a given gravitational lens model fits a source brightness distribution to interferometric radio data in a similar way as standard Clean does in the unlensed case. The lens model parameters can then be varied in order to minimize the residuals and determine the best model for the lens mass distribution. Our variant of this method is improved in order to be useful and stable even for high dynamic range systems with nearly degenerated lens model parameters. Our test case B0218+357 is dominated by two bright images but the information needed to constrain the unknown parameters is provided only by the relatively smooth and weak Einstein ring. The new variant of LensClean is able to fit lens models even in this difficult case. In order to allow the use of general mass models with LensClean, we develop the new method LenTil which inverts the lens equation much more reliably than any other method. This high reliability is essential for the use as part of LensClean. Finally...

  7. Application for vibration monitoring of aspheric surface machining based on wireless sensor networks

    Science.gov (United States)

    Han, Chun Guang; Guo, Yin Biao; Jiang, Chen

    2010-05-01

    Any kinds of tiny vibration of machine tool parts will have a great influence on surface quality of the workpiece at ultra-precise machining process of aspheric surface. At present the major way for decreasing influence of vibration is machining compensation technology. Therefore it is important for machining compensation control to acquire and transmit these vibration signals effectively. This paper presents a vibration monitoring system of aspheric surface machining machine tool based on wireless sensor networks (WSN). Some key issues of wireless sensor networks for vibration monitoring system of aspheric surface machining are discussed. The reliability of data transmission, network communication protocol and synchronization mechanism of wireless sensor networks are studied for the vibration monitoring system. The proposed system achieves multi-sensors vibration monitoring involving the grinding wheel, the workpiece and the workbench spindle. The wireless transmission of vibration signals is achieved by the combination with vibration sensor nodes and wireless network. In this paper, these vibration sensor nodes are developed. An experimental platform is structured which employs wireless sensor networks to the vibration monitoring system in order to test acquisition and wireless transmission of vibration signal. The test results show that the proposed system can achieve vibration data transmission effectively and reliability and meet the monitoring requirements of aspheric surface machining machine tool.

  8. 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

  9. 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.

  10. Lens designs by ray tracing analyses for high-performance reflection optical modules

    International Nuclear Information System (INIS)

    Three kinds of novel optical modules are designed for high-efficiency light concentration. Each optical module consists of three components, namely a reflector, a second optical element (SOE) with a different parabolic profile and a concentrating lens. A concentrating lens with various profile designs is installed at the open end of the reflector to improve the uniformity of ray irradiances collected at the solar cell chip. An effective process for finding the optimum design for the geometries of these optical modules is presented to obtain good uniformity in ray irradiance distribution and high optical performance. The results of ray tracing simulations indicate that the optimum design is achieved based on the principle or the compromise of having the lowest value of the highest peak of ray irradiances and the highest optical performance. The optical module designed without a concentrating lens has a relatively high peak at the center of the circular irradiance distribution. The use of a Fresnel lens can impede the high peak effectively and achieve very good optical performance. Modules with spherical and aspherical concentrating lenses have irradiance peaks that are much higher than that of the Fresnel lens although their performance is negligibly higher than that of the Fresnel lens

  11. Hyper-hemispheric lens distortion model for 3D-imaging SPAD-array-based applications

    Science.gov (United States)

    Pernechele, Claudio; Villa, Federica A.

    2015-09-01

    Panoramic omnidirectional lenses have the typical draw-back effect to obscure the frontal view, producing the classic "donut-shape" image in the focal plane. We realized a panoramic lens in which the frontal field is make available to be imaged in the focal plane together with the panoramic field, producing a FoV of 360° in azimuth and 270° in elevation; it have then the capabilities of a fish eye plus those of a panoramic lens: we call it hyper-hemispheric lens. We built and test an all-spherical hyper-hemispheric lens. The all-spherical configuration suffer for the typical issues of all ultra wide angle lenses: there is a large distortion at high view angles. The fundamental origin of the optical problems resides on the fact that chief rays angles on the object side are not preserved passing through the optics preceding the aperture stop (fore-optics). This effect produce an image distortion on the focal plane, with the focal length changing along the elevation angles. Moreover, the entrance pupil is shifting at large angle, where the paraxial approximation is not more valid, and tracing the rays appropriately require some effort to the optical designer. It has to be noted here as the distortion is not a source-point-aberrations: it is present also in well corrected optical lenses. Image distortion may be partially corrected using aspheric surface. We describe here how we correct it for our original hyper-hemispheric lens by designing an aspheric surface within the optical train and optimized for a Single Photon Avalanche Diode (SPAD) array-based imaging applications.

  12. Profile measurement of aspheric surfaces using scanning deflectometry and rotating autocollimator with wide measuring range

    International Nuclear Information System (INIS)

    High-accuracy aspherical mirrors and lenses with large dimensions are widely used in large telescopes and other industry fields. However, the measurement methods for large aspherical optical surfaces are not well established. Scanning deflectometry is used for measuring optical signals near flat surfaces with uncertainties on subnanometer scales. A critical issue regarding scanning deflectometry is that high-accuracy autocollimators (AC) have narrow angular measuring ranges and are not suitable for measuring surfaces with large slopes and angular changes. The goal of our study is to measure the profile of large aspherical optical surfaces with an accuracy of approximately 10 nm. We have proposed a new method to measure optical surfaces with large aspherical dimensions and large angular changes by using a scanning deflectometry method. A rotating AC was used to increase the allowable measuring range. Error analysis showed that the rotating AC reduces the accuracy of the measurements. In this study, we developed a new AC with complementary metal-oxide semiconductor (CMOS) as a light-receiving element (CMOS-type AC). The CMOS-type AC can measure wider ranges of angular changes, with a maximum range of 21 500 µrad (4500 arcsec) and a stability (standard deviation) of 0.1 µrad (0.02 arcsec). We conducted an experiment to verify the effectivity of the wide measuring range AC by the measurement of a spherical mirror with a curvature radius of 500 mm. Furthermore, we conducted an experiment to measure an aspherical optical surface (an off-axis parabolic mirror) and found an angular change of 0.07 rad (4 arcdegrees). The repeatability (average standard deviation) for ten measurements of the off-axis parabolic mirror was less than 4 nm. (paper)

  13. Len Yi Part 2

    OpenAIRE

    Bsod nams rgyal mtshan

    2011-01-01

    INTRODUCTION: Sonan Jetsun (Bsod nams rgyal mtshan) filmed this material 12-22 January 2008 in Len yi (Lianyi) Village, Sgong po (Gongbo) Township, Sde rong (Derong) County, Dkar mdzes (Ganzi) Tibetan Autonomous Prefecture, Si khron (Sichuan) Province, PR China. The film features the Tibetan New Year, Bkra shis Temple, and ordinary people's lives in Len yi Village. Sonan Jetsun also edited the material and plans to give it to Len yi villagers on DVD/ VCD. LOCATION: Lianyi Village is 200 k...

  14. Flattop mode shaping of a vertical cavity surface emitting laser using an external-cavity aspheric mirror.

    Science.gov (United States)

    Yang, Zhaohui; Leger, James

    2004-11-01

    Both square-shaped and circular-shaped flattop modes were experimentally demonstrated in extended-cavity broad-area VCSELs using aspheric feedback mirrors. These refractive aspheric mirrors were fabricated by electron-beam lithography on curved substrates. Excellent single-mode operation and improved power extraction efficiency were observed. The three-mirror structure of the VCSEL and the state-of-the-art fabrication of the aspheric mirror contribute to the superior VCSEL performance. The modal loss analysis using a rigid three-mirror-cavity simulation method is discussed. PMID:19484117

  15. Lens auto-centering

    Science.gov (United States)

    Lamontagne, Frédéric; Desnoyers, Nichola; Doucet, Michel; Côté, Patrice; Gauvin, Jonny; Anctil, Geneviève; Tremblay, Mathieu

    2015-09-01

    In a typical optical system, optical elements usually need to be precisely positioned and aligned to perform the correct optical function. This positioning and alignment involves securing the optical element in a holder or mount. Proper centering of an optical element with respect to the holder is a delicate operation that generally requires tight manufacturing tolerances or active alignment, resulting in costly optical assemblies. To optimize optical performance and minimize manufacturing cost, there is a need for a lens mounting method that could relax manufacturing tolerance, reduce assembly time and provide high centering accuracy. This paper presents a patent pending lens mounting method developed at INO that can be compared to the drop-in technique for its simplicity while providing the level of accuracy close to that achievable with techniques using a centering machine (usually innovative auto-centering method is based on the use of geometrical relationship between the lens diameter, the lens radius of curvature and the thread angle of the retaining ring. The autocentering principle and centering test results performed on real optical assemblies are presented. In addition to the low assembly time, high centering accuracy, and environmental robustness, the INO auto-centering method has the advantage of relaxing lens and barrel bore diameter tolerances as well as lens wedge tolerances. The use of this novel lens mounting method significantly reduces manufacturing and assembly costs for high performance optical systems. Large volume productions would especially benefit from this advancement in precision lens mounting, potentially providing a drastic cost reduction.

  16. 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

  17. Blu-ray disk lens as the objective of a miniaturized two-photon fluorescence microscope.

    Science.gov (United States)

    Chung, Hsiang-Yu; Kuo, Wei-Cheng; Cheng, Yu-Hsiang; Yu, Che-Hang; Chia, Shih-Hsuan; Lin, Cheng-Yung; Chen, Jie-Shin; Tsai, Huai-Jen; Fedotov, Andrey B; Ivanov, Anatoly A; Zheltikov, Aleksei M; Sun, Chi-Kuang

    2013-12-16

    In this paper, we examine the performance of a Blu-ray disk (BD) aspheric lens as the objective of a miniaturized scanning nonlinear optical microscope. By combining a single 2D micro-electro mechanical system (MEMS) mirror as the scanner and with different tube lens pairs, the field of view (FOV) of the studied microscope varies from 59 μm × 93 μm up to 178 μm × 280 μm, while the corresponding lateral resolution varies from 0.6 μm to 2 μm for two-photon fluorescence (2PF) signals. With a 34/s video frame rate, in vivo dynamic observation of zebrafish heartbeat through 2PF of the excited green fluorescence protein (GFP) is demonstrated. PMID:24514733

  18. Non-isothermal molding technology research of ultra-precision glass lens

    Science.gov (United States)

    Zang, Hongbin; Yu, Jiaxin; Zhou, Yingyue; Tao, Bo

    2014-12-01

    This paper aims to research a unique non-isothermal molding technology (NGMP) which is an attractive and creative manufacturing method of fabricating ultra-precision and high-quality glass components. It has numerous advantages such as high efficiency, low cost and being mass production of glass lenses in industry. This technology is an ultra precision manufacturing process and suitable for multi-scale precision glass lens, lens array and glass micro-structure. This technology overcomes the disadvantages of traditional grinding and polishing technology such as long time production cycle, profligacy of raw materials, single-piece production and difficulty to produce an aspherical lens or arrays. The characteristics of NGMP are studied by comparing with the traditional IGMP. Residual stresses inside the glass lenses are also studied by numerical simulation. Based on the experiments and simulations results, a new compression molding process is proposed. Once the glass lens is fabricated by compression molding, an annealing process can be used to reduce the residual stresses in the glass lens.

  19. Use of the Humphrey Lens Analyzer for off-axis measurements of spectacle lenses.

    Science.gov (United States)

    Atchison, D A; Kris, M; Sheedy, J E; Bailey, I L

    1991-04-01

    Automated focimeters can be used to make quick, precise measurements of off-axis power and prismatic effects corresponding to an eye rotating behind a spectacle lens. An automated focimeter, the Humphrey Lens Analyzer, was assessed in this regard. The Humphrey Lens Analyzer can be used to give a valid measure of off-axis power of lenses with low power, but not of lenses with moderate to higher power (greater than 3 D). For 3 D spherical lenses discrepancies of the order of 0.1 D occur at 30 degrees rotation, and 6 D spheres give discrepancies of 0.5 D at the same rotation. Small discrepancies were found for measurements of prism. The Humphrey Lens Analyzer was also used in a mode where the lens being tested is rotated about the center of curvature of its back surface. This is the mode often used to assess aberrations and prism of progressive-addition lenses. In this mode, the instrument provides reasonable accuracy in estimating off-axis power corresponding to eye rotation for lenses with low power, but not for lenses with moderate to higher power (greater than 3 D). However, it provides accurate values of the variation in off-axis surface power for low powered lenses with aspheric front surfaces. There were considerable systematic errors associated with the measurement of prism. A simple raytracing method was developed to predict the results of measurements with the Humphrey Lens Analyzer. Predictions of off-axis power were good when lenses were rotated about a position corresponding to the center-of-rotation of an eye, but were poorer when lenses were rotated about the center of curvature of their back surfaces. Predictions of primatic efforts were good in both situations. A method by which the Humphrey Lens Analyzer should provide an accurate measurement of off-axis powers corresponding to eye rotation behind a spectacle lens is described, but has not been tested. PMID:2052286

  20. 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...

  1. Generation of Aspherical Optical Lenses via Arrested Spreading and Pinching of a Cross-Linkable Liquid.

    Science.gov (United States)

    Roy, Abhijit Chandra; Yadav, Mridul; Arul, Edward Peter; Khanna, Anubhav; Ghatak, Animangsu

    2016-05-31

    Aspherical optical lenses with spatially varying curvature are desired for capturing high quality, aberration free images in numerous optical applications. Conventionally such lenses are prepared by multistep top-down processes which are expensive, time-consuming, and prone to high failure rate. In this context, an alternate method is presented here based on arrested spreading of a sessile drop of a transparent, cross-linkable polymeric liquid on a solid substrate heated to an elevated temperature. Whereas surface tension driven flow tends to render it spherical, rapid cross-linking arrests such flow so that nonequilibrium aspherical shapes are attained. It is possible to tune also the initial state of the drop via delayed pinching of a liquid cylinder which precedes its release on the substrate. This method has led to the generation of a wide variety of optical lenses, ranging from spherical plano convex to superspherical solid immersion to exotic lenses not achieved via conventional methods. PMID:27200461

  2. Optimal design of tilt carrier frequency computer-generated holograms to measure aspherics.

    Science.gov (United States)

    Peng, Jiantao; Chen, Zhe; Zhang, Xingxiang; Fu, Tianjiao; Ren, Jianyue

    2015-08-20

    Computer-generated holograms (CGHs) provide an approach to high-precision metrology of aspherics. A CGH is designed under the trade-off among size, mapping distortion, and line spacing. This paper describes an optimal design method based on the parametric model for tilt carrier frequency CGHs placed outside the interferometer focus points. Under the condition of retaining an admissible size and a tolerable mapping distortion, the optimal design method has two advantages: (1) separating the parasitic diffraction orders to improve the contrast of the interferograms and (2) achieving the largest line spacing to minimize sensitivity to fabrication errors. This optimal design method is applicable to common concave aspherical surfaces and illustrated with CGH design examples. PMID:26368782

  3. 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.

  4. 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.

  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. Comparisons of amplitude of pseudoaccommodation with aspheric yellow, spheric yellow, and spheric clear monofocal intraocular lenses

    OpenAIRE

    Nishi T.; Taketani F; Ueda T; Ogata N.

    2013-01-01

    Tomo Nishi, Futoshi Taketani, Tetsuo Ueda, Nahoko Ogata Department of Ophthalmology, Nara Medical University, Kashihara City, Nara, Japan Purpose: To determine the amplitude of pseudoaccommodation and higher-order aberrations with three types of implanted monofocal intraocular lenses (IOLs): aspheric yellow (IQ); spheric yellow (NT); and spheric clear (AT). Setting: Department of Ophthalmology, Nara Medical University, Nara, Japan. Methods: We studied 60 patients who underwent small incision...

  7. Sensitivity of off-axis performance of aspheric spectacle lenses to tilt and decentration.

    Science.gov (United States)

    Atchison, D A; Tame, S A

    1993-10-01

    Apparatus was modified to measure, and theoretical raytracing was used to predict, off-axis powers of spectacle lenses in the presence of tilt or decentration. In response to poor fitting in the form of tilt or decentration, lenses with aspheric front surfaces were found to have greater off-axis power errors than best-form lenses with spherical surfaces. This is attributable to the aspheric lenses having flatter surfaces than the spherical lenses. The errors are up to twice those occurring for the spherical lenses, and can be quite high, e.g. 0.9 D astigmatism for +6D power with 10 degrees tilt in 20 degrees upgaze. Negative lenses are more sensitive to poor fitting than are positive lenses of the same power. The errors for straight ahead vision associated with tilt are approximately proportional to the square of the angle of tilt, and the errors for straight ahead vision associated with decentration are approximately proportional to the square of decentration. It is most important that aspheric lenses be correctly fitted, which means that each 2 degrees of pantascopic tilt should be accompanied by approximately 1 mm decentration. PMID:8278198

  8. Reflections From a Fresnel Lens

    Science.gov (United States)

    Keeports, David

    2005-01-01

    Reflection of light by a convex Fresnel lens gives rise to two distinct images. A highly convex inverted real reflective image forms on the object side of the lens, while an upright virtual reflective image forms on the opposite side of the lens. I describe here a set of laser experiments performed upon a Fresnel lens. These experiments provide…

  9. Internet based post-graduate course in spectacle lens design

    Science.gov (United States)

    Jalie, Mo

    2014-07-01

    The complexity of spectacle lenses has increased enormously over the last three decades. The advent of aspheric lenses for the normal power range and the, now commonplace, progressive lenses for the correction of presbyopia, are just two examples of 21st Century technology. Freeform surfaces are now employed to personalize lenses to wearer's needs and these may be both progressive and atoroidal in nature. At the same time, optometry has taken a sideways step from optics and physics into a more general primary health care profession with an ever-increasing amount of biological and medical content added to an already brimming curriculum, hence the need for persons without optometry training to undertake the study of spectacle lenses. Some years ago a post-graduate course was designed for opticians who had a good grasp of mathematics and the ability to pay close attention to detail in the lengthy trigonometric ray-tracing techniques employed in lens design calculations. The year-long course, is undertaken by distance learning, and has been undertaken via the internet by students from many countries around the world. Final assessment is by means of examination held by the Association of British Dispensing Opticians and takes the form of two three-hour papers, Paper One consisting of the determination of the aberrations of a spectacle lens by accurate trigonometric ray tracing and the second, a general paper on the optics of ophthalmic lenses. It leads to the professional qualification, ABDO (Hons) SLD.

  10. Contact Lens Risks

    Science.gov (United States)

    ... Health and Consumer Devices Consumer Products Contact Lenses Contact Lens Risks Share Tweet Linkedin Pin it More ... redness blurred vision swelling pain Serious Hazards of Contact Lenses Symptoms of eye irritation can indicate a ...

  11. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Sep 10, 2015 Contact Lens Horror Stories: Poor Care Can Lead to Blindness Sep 09, 2015 How to Correct High Myopia Feb 27, 2015 More Eye Health News Pet Fish Fitted with Fake Eye in ...

  12. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. ...

  13. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lens because they can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, ... placed on the eye can lower internal eye pressure by about 20 percent for half a year. ...

  14. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... had not been properly fitted by an eye care professional, the lenses stuck to my eye like ... lenses do not require the same level of care or consideration as a standard contact lens because ...

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... same level of care or consideration as a standard contact lens because they can be purchased over- ... lifestyle choices can directly affect your eyes. The best way to take care of your eyes during ...

  16. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lenses do not require the same level of care or consideration as a standard contact lens because they can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ...

  17. Terahertz Artificial Dielectric Lens

    Science.gov (United States)

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-03-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices.

  18. Minimum lens complexity design approach for a free-space macro-optical multichip global interconnection module

    Science.gov (United States)

    Milojkovic, Predrag; Christensen, Marc P.; Haney, Michael W.

    2000-05-01

    The FAST-Net (Free-space Accelerator for Switching Terabit Networks) concept uses an array of wide field-of-view imaging lenses to realize a high-density shuffle interconnect across an array of smart-pixel integrated circuits. This paper presents a design approach for these lenses that achieves the minimum complexity required to meet the demands of the FAST-Net concept's off-axis multi-chip environment. Generalized eikonals for arbitrary surfaces were examined to determine the performance bounds for the FAST-Net optical system. Then an analysis provided an estimate of 6 for the number of spherical surfaces needed to achieve good optical resolution and distortion performance across an array of 10-micron diameter VCSEL sources that are imaged onto a array of 50-micron wide detectors. A ray trace simulation confirmed this number. Subsequent analysis evaluated the achievable efficient of replacing spherical surfaces with aspherical ones. By exploiting the mismatch between the low numerical aperture VCSELs and relatively higher numerical aperture interconnection optics, it was found that 3 aspherical surfaces could replace 6 spherical surfaces in the FAST-Net system for the specified performance criteria. A lens design that utilizes 3 aspherical surfaces and achieves necessary registration and resolution of the FAST-Net system was determined. The results provide a general framework for the design of wide field-of-view free space interconnection systems that incorporate high-density VCSEL arrays.

  19. Multi-aspheric description of the myopic cornea after different refractive treatments and its correlation with corneal higher order aberrations

    Science.gov (United States)

    Queirós, António; Villa-Collar, César; Jorge, Jorge; Gutiérrez, Ángel Ramón; González-Méijome, José Manuel

    2012-01-01

    Background To analyse the asphericity of the anterior corneal surface (ACS) for different diameters, and correlate those values with corneal higher order aberrations (cHOA) before and after myopic treatments with corneal refractive therapy (CRT) for orthokeratology and customized (CL) and standard laser (SL) assisted in situ keratomileusis (LASIK). Setting Clínica Oftalmológica NovoVisión, Madrid, Spain. Methods The right eyes of 81 patients (27 in each treatment group), with a mean age of 29.94 ± 7.5 years, were analysed. Corneal videokeratographic data were used to obtain corneal asphericity (Q) for different corneal diameters from 3 to 8 mm and cHOA root mean square (RMS) obtained from Zernike polynomials for a pupil diameter of 6 mm. Results There were statistically significant differences in asphericity values calculated at different corneal diameters for different refractive treatments and their changes. The difference between asphericity at 3 and 8 mm reference diameters showed statistically significant correlations with spherical-like cHOA that was also significantly increased after all procedures. Conclusions The shift in corneal asphericity and the differences among different treatment techniques are more evident for the smaller reference diameters. These differences can be much reduced or even masked for a peripheral reference point at 4 mm from centre, which is used by some corneal topographers.

  20. Challenges in holographic measurement of aspheric and freeform optical components shape

    Czech Academy of Sciences Publication Activity Database

    Lédl, Vít; Psota, Pavel; Vojtíšek, Petr; Doleček, Roman; Mokrý, Pavel; Dlask, Martin

    Vol. 9508. Bellingham: SPIE-INT SOC OPTICAL ENGINEERING, 2015 - (Hrabovsky, M.; Sheridan, J.; Fimia, A.), 95080M-95080M. (SPIE). ISBN 978-1-62841-629-9. ISSN 0277-786X. [Conference on Holography - Advances and Modern Trends IV. Prague (CZ), 15.04.2015-16.04.2015] R&D Projects: GA MŠk(CZ) LO1206 Institutional support: RVO:61389021 Keywords : Holographic contouring * Multidirection illumination * Dualwavelength * Aspheric * Freeform * Polished Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2293341

  1. Super-polishing of Zerodur aspheres by means of conventional polishing technology

    Czech Academy of Sciences Publication Activity Database

    Polák, Jaroslav; Klepetková, Eva; Pošmourný, Josef; Šulc, Miroslav; Procháska, František; Tomka, David; Matoušek, Ondřej; Poláková, Ivana; Šubert, Eduard

    Vol. 9442. Bellingham : SPIE-INT SOC OPTICAL ENGINEERING, 2015 - (Kovačičinová, J.; Vít, T.), s. 944212-944212 ISBN 978-1-62841-557-5. ISSN 0277-786X. - (SPIE). [Optics and Measurement Conference 2014 (OaM 2014). Liberec (CZ), 07.10.2014-10.10.2014] R&D Projects: GA MŠk(CZ) LO1206 Institutional support: RVO:61389021 Keywords : super-polishing * smoothing * roughness reduction * bowl-feed polishing * aspheric polishing Subject RIV: JP - Industrial Processing http://dx.doi.org/10.1117/12.2175899

  2. 高次非球面的工艺技术研究%Manufacturing technology for high order aspheric surface

    Institute of Scientific and Technical Information of China (English)

    袁吕军; 陈韬

    2011-01-01

    Since high order aspheric surface finds significant applications in optical system, a rapid and effective manufacturing technology is required to meet the demand. Software was developed with VC6. 0 for aspheric calculation to help fabrication, and a new compensation test was proposed for high order aspheric surface. Taking a high order aspheric collector with the diameter of 244mm as example, a manufacturing technology was developed and related investigations were conducted. Based on milling process and aspheric surface characteristics, several new grinding methods were proposed and related mathematical models were built. In order to process high order aspheric surface efficiently, computerized numerical control (CNC) milling direct shaping method was tested to reduce the complexity of subsequent processes, and numerical controlled small tool was combined with full aperture craft in polishing process to make aspheric surface smoother. Experimental results demonstrate the high order aspheric manufacturing technology is efficient, low cost and precise.%高次非球面在光学系统应用中意义重大,但是一直以来缺乏一套快速、有效的工艺方法.利用VC6.0编制了一款面型计算软件以辅助加工,并提出了一种新的高次非球面补偿检验方法.针对一块巡天光谱仪中口径φ244 mm的一面平面另一面为高次非球面的改正镜开展工艺方法的设计与研究,从铣磨成形开始,根据高次非球面的特点提出了几种新型磨削工艺,建立相应的数学模型.由于高次非球面的特殊性,试验了数控铣磨直接成型法,很大程度上降低后继工艺难度,在细磨和抛光阶段采用数控小工具和整工具研磨相结合,能够很好地克服面型不平滑等技术难题.总结出了一套高效率、低成本、高精度的高次非球面工艺方法.

  3. Luneburg lens in silicon photonics

    OpenAIRE

    Di Falco, Andrea; Kehr, Susanne C; Leonhardt, Ulf

    2011-01-01

    The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms. (C) 2011 Optical Society of America

  4. Frequency selective lens antenna

    OpenAIRE

    Thornton, J.; Haines, P.

    2007-01-01

    A variant of the hemispherical microwave lens antenna is reported where the ground plane region is modified through use of a frequency selective surface. This allows discrimination of frequencies by two closely spaced primary feeds. A scale model is reported operating at 12 and 30 GHz.

  5. Design of Ultra-Precision CNC Grinding Machine and Its Application in Machining Large Aspheric Mirrors

    Institute of Scientific and Technical Information of China (English)

    Bin Li; Huiying Zhao; Jianpu Xi; Dongxu Ren

    2015-01-01

    Large aspheric mirrors are needed for the remote sensing and ground based telescope optical systems, these mirrors are made of hard and brittle materials which require ultra⁃precision grinding process to guarantee the high profile accuracy and machining efficiency. The ultra⁃precision aspheric CNC grinding machine (UAG900) is presented by this paper, as well as its grinding capability. The hydrostatic bearings of high accuracy and stiffness are adopted by the linear and rotary motions to guarantee the mirror accuracy, material removal rate and subsurface damage. Disk type grinding wheel with arc edge is used. The material removal rate can be up to 360 mm3/min to guarantee the machining efficiency during rough grinding using D180 diamond grinding wheel while the fine grinding is performed using D15 grinding wheel. It indicates that the grinding wheel radius measuring error is proportional to the profile error induced by the grinding path. The grinding step size is better to be 0�01 mm for the reduction of the grinding movement accelerations and program length. The grinding path is planned and expressed based on the grinding mode according to the mirror shape. One 540 mm×450 mm×100 mm zerodur mirror is ground and re⁃ground using the measuring data acquired by the Leitz CMM. The final surface accuracy of P⁃V value is less than 5 μm after compensation grinding.

  6. Human lens colouration, age and cataract

    International Nuclear Information System (INIS)

    Full text: The human lens biosynthesises UV filter compounds which effectively remove light in the 300-400nm band. These chemicals are present either as an aid to visual acuity, or to filter out damaging UV radiation. The primate UV filters are 3-hydroxykynurenine analogues derived from the metabolism of tryptophan. We have recently demonstrated that these endogenous UV filters are not innocuous, but are in fact capable of binding to proteins, including the crystalline proteins which make up the bulk of the lens. Thus, over time, the levels of protein - bound UV filters increase and this results in the human lens becoming progressively more yellow as we age. This colouration affects our colour vision and it may also be responsible for the brown colour of lenses which is the hallmark of age-related nuclear cataract. An understanding of the intrinsic instability of the endogenous UV filters, combined with changes in the internal transport of these and other small molecular weight compounds including antioxidants, such as glutathione, is allowing us to gain an insight into the processes responsible for the development of age-related cataract: the major cause of world blindness

  7. 30-Lens interferometer for high-energy X-rays.

    Science.gov (United States)

    Lyubomirskiy, Mikhail; Snigireva, Irina; Kohn, Victor; Kuznetsov, Sergey; Yunkin, Vyacheslav; Vaughan, Gavin; Snigirev, Anatoly

    2016-09-01

    A novel high-energy multi-lens interferometer consisting of 30 arrays of planar compound refractive lenses is reported. Under coherent illumination each lens array creates a diffraction-limited secondary source. Overlapping such coherent beams produces an interference pattern demonstrating strong longitudinal functional dependence. The proposed multi-lens interferometer was tested experimentally at the 100 m-long ID11 ESRF beamline in the X-ray energy range from 30 to 65 keV. The interference pattern generated by the interferometer was recorded at fundamental and fractional Talbot distances. An effective source size (FWHM) of the order of 15 µm was determined from the first Talbot image, proving the concept that the multi-lens interferometer can be used as a high-resolution tool for beam diagnostics. PMID:27577763

  8. 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

  9. Functional modular contact lens

    Science.gov (United States)

    Shum, Angela J.; Cowan, Melissa; Lähdesmäki, Ilkka; Lingley, Andrew; Otis, Brian; Parviz, Babak A.

    2009-08-01

    Tear fluid offers a potential route for non-invasive sensing of physiological parameters. Utilization of this potential depends on the ability to manufacture sensors that can be placed on the surface of the eye. A contact lens makes a natural platform for such sensors, but contact lens polymers present a challenge for sensor fabrication. This paper describes a microfabrication process for constructing sensors that can be integrated into the structure of a functional contact lens in the future. To demonstrate the capabilities of the process, an amperometric glucose sensor was fabricated on a polymer substrate. The sensor consists of platinum working and counter electrodes, as well as a region of indium-tin oxide (ITO) for glucose oxidase immobilization. An external silver-silver chloride electrode was used as the reference electrode during the characterization experiments. Sensor operation was validated by hydrogen peroxide measurements in the 10- 20 μM range and glucose measurements in the 0.125-20 mM range.

  10. Silicone oil-intraocular lens interaction: which lens to use?

    OpenAIRE

    McLoone, E; Mahon, G; Archer, D.; Best, R

    2001-01-01

    AIM—To determine a suitable intraocular lens for implantation in patients at high risk of lens exposure to silicone oil in their lifetime.
METHODS—PMMA, AcrySof, AR40, AQUA-Sense, and Raysoft lenses were examined. Each lens was immersed for 5 minute intervals in balanced salt solution (BSS), in stained silicone oil, and again in BSS before being photographed in air and in BSS. Percentage silicone oil coverage of the lens optic was determined.
RESULTS—The mean percentage coating (MPC) for the ...

  11. Design, fabrication, and testing of micro-optical sensors containing multiple aspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rajic, S.; Egert, C.M.; Evans, B.M. III; Cunningham, J.P.; Marlar, T.A.

    1995-09-01

    The micro-sensor field is presently proliferating with designs and approaches. The authors have developed a micro-spectrometer for sensing application containing five precision surfaces, including two off-axis aspheres. The entire monolith is less than six cubic centimeters in volume. This particular design contains a bandwidth of about 1 micrometer which is centered at 980 nm. Once an appropriate starting substrate was produced, the entire system was diamond turned to maintain the required surface figure, inter-surface spacing, and surface tilts. Only three diamond turned fixtures were needed to produce the monolith. The results proved to be more than adequate for many sensing applications. Slightly altered designs could easily be produced containing different bandwidths and resolutions as needed by the customer. Due to the spectrum of interest and the fabrication method, PMMA was the material chosen for this sensor. Other designs configurations incorporating BK7 and sapphire are presently being studied.

  12. Aspherical nucleosynthesis in a core-collapse supernova with 25 M ☉ standard progenitor

    International Nuclear Information System (INIS)

    The problem of nucleosynthesis was studied within an aspherical supernova model. The explosive burning was computed in a star of 25 M ☉ initial mass on its final stage of evolution. The chemical composition of a presupernova was taken from realistic evolutionary computations. A piecewise parabolic method on a local stencil was applied to simulate the hydrodynamics of the explosion. The gravity was recomputed by a Poisson solver on a fine grid as the explosion developed. A detailed yield of chemical elements was performed as a post-processing step using the tracer particles method. The produced nuclei formed a layer-like structure enclosing large fragments of nickel and iron-group isotopes that were pushed away from the central region by an explosion along the polar direction. The light nuclei were preferentially moving along the equatorial plane forming a torus-like structure.

  13. Crowded, cell-like environment induces shape changes in aspherical protein

    Science.gov (United States)

    Cheung, Margaret

    2009-03-01

    How the crowded environment inside cells affects the structures of proteins with aspherical shapes is a vital question because many proteins and protein--protein complexes in vivo adopt anisotropic shapes. Here we address this question by combining computational and experimental studies of a football-shaped protein (i.e. Borrelia burgdorferi VlsE) under crowded, cell-like conditions. The results show that macromolecular crowding affects protein-folding dynamics as well as overall protein shape. In crowded milieus, distinct conformational changes in VlsE are accompanied by secondary structure alterations that lead to exposure of a hidden antigenic region. Our work demonstrates the malleability of ``native'' proteins and implies that crowding-induced shape changes may be important for protein function and malfunction in vivo.

  14. Aspherical surface profile fitting based on the relationship between polynomial and inner products

    Science.gov (United States)

    Cheng, Xuemin; Yang, Yikang; Hao, Qun

    2016-01-01

    High-precision aspherical polynomial fitting is essential to image quality evaluation in optical design and optimization. However, conventional fitting methods cannot reach optimal fitting precision and may somehow induce numerical ill-conditioning, such as excessively high coefficients. For this reason, a projection from polynomial equations to vector space was here proposed such that polynomial solutions could be obtained based on matrix and vector operation, so avoiding the problem of excessive coefficients. The Newton-Raphson iteration method was used to search for optimal fitting of the spherical surface. The profile fitting test showed that the proposed approach was able to obtain results with high precision and small value, which solved the numerical ill-conditioning phenomenon effectively.

  15. 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 ...

  16. The Optimal Gravitational Lens Telescope

    CERN Document Server

    Surdej, J; Coleman, P; Dominik, M; Habraken, S; Hanot, C; Coroller, H Le; Mawet, D; Quintana, H; Sadibekova, T; Sluse, D; 10.1088/0004-6256/139/5/1935

    2010-01-01

    Given an observed gravitational lens mirage produced by a foreground deflector (cf. galaxy, quasar, cluster,...), it is possible via numerical lens inversion to retrieve the real source image, taking full advantage of the magnifying power of the cosmic lens. This has been achieved in the past for several remarkable gravitational lens systems. Instead, we propose here to invert an observed multiply imaged source directly at the telescope using an ad-hoc optical instrument which is described in the present paper. Compared to the previous method, this should allow one to detect fainter source features as well as to use such an optimal gravitational lens telescope to explore even fainter objects located behind and near the lens. Laboratory and numerical experiments illustrate this new approach.

  17. Advances in lens implant technology

    OpenAIRE

    Kook, Daniel; Kampik, Anselm; Dexl, Alois K.; Zimmermann, Nicole; Glasser, Adrian; Baumeister, Martin; Kohnen, Thomas

    2013-01-01

    Cataract surgery is one of the oldest and the most frequent outpatient clinic operations in medicine performed worldwide. The clouded human crystalline lens is replaced by an artificial intraocular lens implanted into the capsular bag. During the last six decades, cataract surgery has undergone rapid development from a traumatic, manual surgical procedure with implantation of a simple lens to a minimally invasive intervention increasingly assisted by high technology and a broad variety of imp...

  18. Connexin hemichannels in the lens

    OpenAIRE

    EricCBeyer

    2014-01-01

    The normal function and survival of cells in the avascular lens is facilitated by intercellular communication through an extensive network of gap junctions formed predominantly by three connexins (Cx43, Cx46, and Cx50). In expression systems, these connexins can all induce hemi-channel currents, but other lens proteins (e.g., pannexin1) can also induce similar currents. Hemichannel currents have been detected in isolated lens fiber cells. These hemichannels may make significant contributio...

  19. Connexin hemichannels in the lens

    OpenAIRE

    Beyer, Eric C.; Berthoud, Viviana M.

    2014-01-01

    The normal function and survival of cells in the avascular lens is facilitated by intercellular communication through an extensive network of gap junctions formed predominantly by three connexins (Cx43, Cx46, and Cx50). In expression systems, these connexins can all induce hemichannel currents, but other lens proteins (e.g., pannexin1) can also induce similar currents. Hemichannel currents have been detected in isolated lens fiber cells. These hemichannels may make significant contributions t...

  20. Dispersion-compensated fresnel lens

    Science.gov (United States)

    Johnson, Kenneth C.

    1992-01-01

    A transmission grating is used to reduce chromatic aberration in a Fresnel lens, wherein the lens chromatic dispersion is offset and substantially canceled by the grating's diffraction-induced dispersion. The grating comprises a Fresnel-type pattern of microscopic facets molded directly into the lens surface. The facets would typically have a profile height of around 4.multidot.10.sup.-5 inch and a profile width of at least 10.sup.-3 inch. In its primary intended application, the invention would function to improve the optical performance of a Fresnel lens used to concentrate direct sunlight.

  1. 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.

  2. Development of lens sutures.

    Science.gov (United States)

    Kuszak, Jer R; Zoltoski, Rebecca K; Tiedemann, Clifford E

    2004-01-01

    Cylindrical map projections (CMPs) have been used for centuries as an effective means of plotting the features of a 3D spheroidal surfaces (e.g. the earth) on a 2D rectangular map. We have used CMPs to plot primate fiber cell organization from selected growth shells as a function of growth, development and aging. Lens structural parameters and features were derived from slit-lamp, light and transmission and scanning electron micrographs. This information was then used to create CMPs of lenses that were then correlated with azimuthal map projections (AMPs; projections that are radially symmetric around a central point [the poles]) to reveal different suture patterns during distinct time periods. In this manner, both lens fiber and suture branch locations are defined by degrees of longitude and latitude. CMPs and AMPs confirm that throughout defined periods of development, growth and ageing, increasingly complex suture patterns are formed by the precise ordering of straight and opposite end curvature fibers. However, the manner in which additional suture branches are formed anteriorly and posteriorly is not identical. Anteriorly, new branches are added between extant branches. Posteriorly, pairs of new branches are formed that progressively overlay extant branches. The advantage of using CMPs is that the shape and organization of every fiber in a growth shell can be observed in a single image. Thus, the use of CMPs to plot primate fiber cell organization has revealed more complex aspects of fiber formation that may explain, at least in part, changes in lens optical quality as a function of age and pathology. In addition, more accurate measurements of fiber length will be possible by incorporating the latitudinal and longitudinal locations of fibers. PMID:15558480

  3. Lens of Eye Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Mallett, Michael Wesley [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-23

    An analysis of LANL occupational dose measurements was made with respect to lens of eye dose (LOE), in particular, for plutonium workers. Table 1 shows the reported LOE as a ratio of the “deep” (photon only) and “deep+neutron” dose for routine monitored workers at LANL for the past ten years. The data compares the mean and range of these values for plutonium workers* and non-routine plutonium workers. All doses were reported based on measurements with the LANL Model 8823 TLD.

  4. Diffractive Alvarez lens

    International Nuclear Information System (INIS)

    A diffractive Alvarez lens is demonstrated that consists of two separate phase plates, each having complementary 16-level surface-relief profiles that contain cubic phase delays. Translation of these two components in the plane of the phase plates is shown to produce a variable astigmatic focus. Both spherical and cylindrical phase profiles are demonstrated with good accuracy, and the discrete surface-relief features are shown to cause less than λ/10 wave-front aberration in the transmitted wave front over a 40 mmx80 mm region. (c) 2000 Optical Society of America

  5. Vitamin C–mediated Maillard Reaction in the Lens Probed in a Transgenic-mouse Model

    OpenAIRE

    Fan, Xingjun; Monnier, Vincent M.

    2008-01-01

    Aging human lens crystallins are progressively modified by yellow glycation, oxidation, and cross-linked carbonyl compounds that have deleterious properties on protein structure and stability. In order to test the hypothesis that some of these compounds originate from oxidized vitamin C, we have overexpressed the human vitamin C transporter 2 (hSCVT2) in the mouse lens. We find that levels of ascorbic and dehydroascorbic acid are highly elevated compared to the wild type and that the lenses h...

  6. Two-photon excited fluorescence of the lens for the diagnosis of presbyopia

    Science.gov (United States)

    Steiner, R.; Kessler, M.; Fugger, O.; Dolp, F.; Russ, D.

    2009-09-01

    Presbyopia is a wide spread phenomenon in elder people and is caused by the hardening of the lens in human eyes. Research is performed to make such lenses again more flexible by application of geometrically optimised cuts through the lens with a femtosecond-laser. Different protein agglomerations are responsible for the flexibility reduction of the lens. Two-photon excited fluorescence of the lens can be used as a diagnostic tool to localise such protein accumulations. In in-vitro experiments with human cataract lenses and also lenses of the Philly-mouse it could be demonstrated that with age the fluorescence increases as presbyopia proceeds. The distribution of the fluorescing compounds are not homogeneous but rather cloudy. Discrimination of the compounds by fluorescence lifetime measurements in relation of the depth in the lens is possible.

  7. The ultrahigh precision form measurement of small, steep-sided aspheric moulds, incorporating novel hardware and software developments; Technical Digest

    Science.gov (United States)

    Mills, M. W.; Hutchinson, Matthew J.

    2005-05-01

    A variety of consumer applications, eg cellphone camera lenses, optical storage devices, digital cameras, etc, are driving the demand for small, high aspheric departure rotationally-symmetric moulded optics, manufactured both in polymer and glass materials. The mould tools for such components are manufactured by ultra-high precision techniques such as single point diamond turning and ultra-precision grinding, and must be accurate to mould.

  8. Shack-Fizeau interferometer and some methods to process their aspheric wavefront interferograms using a CCD detector

    Science.gov (United States)

    Rivera, Mariano; Garcia, J.; Malacara, D.; Marroquin, Jose L.

    1996-02-01

    A Fizeau interferometer has been built to test aspherical and concave telescope mirrors. Results of one method used to evaluate the maximum number of fringes when the interferogram image is projected on a CCD device are mentioned. Some complementary techniques have been utilized to analyze interferograms using this kind of interferometer. A deterministic approach to the regularization term added by Marroquin and Rivera (1995) to the least-squares unwrapping technique is shown.

  9. Excimer laser micromachining of aspheric microlens arrays based on optimal contour mask design and laser dragging method.

    Science.gov (United States)

    Chiu, Chi-Cheng; Lee, Yung-Chun

    2012-03-12

    This paper presents an improved excimer laser micromachining method for fabricating arrayed microstructures with a predesigned surface profile. The proposed method is developed from a conventional biaxial laser dragging method, but numerical analysis and optimal pattern design on the contour mask are introduced so that the machined surface profiles can be well controlled and matched to the designed profiles. To demonstrate the capability of this new approach, an array of aspheric microlenses that have analog surfaces for minimizing the focal spot sizes of the lenses is designed and fabricated. An array of 10×10 microlenses with an aperture size of 100 μm and a designed aspheric profile are obtained experimentally. The machined surface profiles are closely matched to their designed ones, with a profile deviation of less than 1 μm. Furthermore, the machined surfaces are smooth, with an average surface roughness of around 2 nm. Optical measurements on these machined aspheric microlenses show minimized focal spot sizes approaching their optical diffraction limits. PMID:22418468

  10. 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.

  11. 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.

  12. Production of {sup 44}Ti in neutrino-driven aspherical supernova explosions

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Shin-ichiro [Kumamoto National College of Technology, 2659-2 Suya, Goshi 861-1102 (Japan); Ono, Masaomi; Hashimoto, Masa-aki [Department of Physics, School of Sciences, Kyushu University, Fukuoka 810-8560 (Japan); Kotake, Kei [National Astronomical Observatory Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan)

    2014-05-02

    We examine the synthesis of {sup 44}Ti in a neutrino-driven aspherical supernova (SN), focusing on reaction rates related to {sup 44}Ti and rotation of a progenitor. We have performed 2D hydrodynamic simulations of SN of a 15M{sub ⊙} progenitor, whose angular velocity is manually set to be a cylindrical distribution and have followed explosive nucleosynthesis in the ejecta. We find that the faster rates of {sup 40}Ca(α,γ){sup 44}Ti and the slower rate of {sup 44}Ti(α,p){sup 47}V lead to more massive ejection of {sup 44}Ti and {sup 56}Ni and larger ratios <{sup 44}Ti/{sup 56}Ni>. Faster rotation also results in more massive ejection of {sup 44}Ti and {sup 56}Ni. Ratios <{sup 44}Ti/{sup 56}Ni> are however independent from rotation. Large masses of {sup 44}Ti and large ratios observed in SN 1987A and Cas A (> 1O{sup −4}M{sub ⊙} and 1-2 respectively) are not realized in all the models.

  13. A modified stitching algorithm for testing rotationally symmetric aspherical surfaces with annular sub-apertures

    Science.gov (United States)

    Hou, Xi; Wu, Fan; Yang, Li; Wu, Shi-bin; Chen, Qiang

    2006-02-01

    Annular sub-aperture stitching technique has been developed for low cost and flexible testing rotationally symmetric aspherical surfaces, of which combining accurately the sub-aperture measurement data corrupted by misalignments into a complete surface figure is the key problem. An existed stitching algorithm of annular sub-apertures can convert sub-aperture Zernike coefficients into full-aperture Zernike coefficients, in which use of Zernike circle polynomials represents sub-aperture data over both circle and annular domain. Since Zernike circle polynomials are not orthogonal over annular dominion, the fitting results may give wrong results. In this paper, the Zernike polynomials and existed stitching algorithm have been reviewed, and a modified stitching algorithm with Zernike annular polynomials is provided. The performances of a modified algorithm on the reconstruction precision are studied by comparing with the algorithm existed. The results of computer simulation show that the sub-aperture data reduction with the modified algorithm is more accurate than that obtained with the existed algorithm based on Zernike circle polynomials, and the undergoing matrix manipulation is simpler.

  14. 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.

  15. Error Correction of a Phase-Only Computer-Generated Hologram for an Aspheric Surface

    Science.gov (United States)

    Zhang, H.; Yan, Y.; Zhou, H.; Qiao, Y. J.; Si, J.; Wang, D.

    2014-09-01

    When applying phase-only computer-generated hologram (CGH) as a standard model of optical measurement in computer-generated holography for aspheric surface testing, it has the advantage of simplifying optical path configuration and improving the diffraction efficiency of the incoming light. However, errors always exists during the encoding process of fabricating multiphase level CGHs and this kind of errors will be amplified level by level in the measurement. According to the analysis of the encoding error, the error of CGH increases linearly when its quantified period increases. For example, if the quantified period is 32, the maximum of encoding error is 16.46 which can lead wave-front aberration 0.085λ of a secondary parabolic surface with 512 x 512 sampling pixels. In this article, an optimization method based on deviation of minimum boundary value has been used to eliminate the encoding error of CGH. In the experiment, we use a liquid crystal spatial light modulator to generate CGHs and measure residuals of reconstructed wave-front of a secondary parabolic surface. The measurement results show that average decrease of the RMS values of the residuals is 0.07λ when their periods range from 3 to 6, which indicates the optimization method is effective.

  16. Improving the quantitative testing of fast aspherics surfaces with null screen using Dijkstra algorithm

    Science.gov (United States)

    Moreno Oliva, Víctor Iván; Castañeda Mendoza, Álvaro; Campos García, Manuel; Díaz Uribe, Rufino

    2011-09-01

    The null screen is a geometric method that allows the testing of fast aspherical surfaces, this method measured the local slope at the surface and by numerical integration the shape of the surface is measured. The usual technique for the numerical evaluation of the surface is the trapezoidal rule, is well-known fact that the truncation error increases with the second power of the spacing between spots of the integration path. Those paths are constructed following spots reflected on the surface and starting in an initial select spot. To reduce the numerical errors in this work we propose the use of the Dijkstra algorithm.1 This algorithm can find the shortest path from one spot (or vertex) to another spot in a weighted connex graph. Using a modification of the algorithm it is possible to find the minimal path from one select spot to all others ones. This automates and simplifies the integration process in the test with null screens. In this work is shown the efficient proposed evaluating a previously surface with a traditional process.

  17. Photothermal Lens Aberration Effects in Two Laser Thermal Lens Spectrometry

    OpenAIRE

    Bialkowski, Stephen E.

    1985-01-01

    A comparison of theories describing two laser photothermal lens signals is given. The aberrant nature of this lens is accounted for in a theory which treats the propagation of a monitor laser in terms of a phase shift in this laser beam wave front. The difference between theories are discussed in terms of the predicted signal strengths and temporal behavior. The aberrant theory results in smaller theoretical signal strengths and different functional relationships between signal and analyte le...

  18. Lens design based on lens form parameters using Gaussian brackets

    Science.gov (United States)

    Yuan, Xiangyu; Cheng, Xuemin

    2014-11-01

    The optical power distribution and the symmetry of the lens components are two important attributes that decide the ultimate lens performance and characteristics. Lens form parameters W and S are the key criteria describing the two attributes mentioned above. Lens components with smaller W and S will have a good nature of aberration balance and perform well in providing good image quality. Applying the Gaussian brackets, the two lens form parameters and the Seidel Aberration Coefficients are reconstructed. An initial lens structure can be analytically described by simultaneous equations of Seidel Aberration Coefficients and third-order aberration theory. Adding the constraints of parameters W and S in the solving process, a solution with a proper image quality and aberration distribution is achieved. The optical properties and image quality of the system based on the parameters W and S are also analyzed in this article. In the method, the aberration distribution can be controlled to some extent in the beginning of design, so that we can reduce some workload of optimization later.

  19. 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.

  20. Adjustable hybrid diffractive/refractive achromatic lens

    OpenAIRE

    Valley, Pouria; Savidis, Nickolaos; Schwiegerling, Jim; Dodge, Mohammad Reza; Peyman, Gholam; N. Peyghambarian

    2011-01-01

    We demonstrate a variable focal length achromatic lens that consists of a flat liquid crystal diffractive lens and a pressure-controlled fluidic refractive lens. The diffractive lens is composed of a flat binary Fresnel zone structure and a thin liquid crystal layer, producing high efficiency and millisecond switching times while applying a low ac voltage input. The focusing power of the diffractive lens is adjusted by electrically modifying the sub-zones and re-establishing phase wrapping po...

  1. Contact Lens Related Corneal Ulcer

    OpenAIRE

    Loh, KY; P Agarwal

    2010-01-01

    A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are: overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. Th...

  2. Inverse Design of Electron Lens

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The inverae design of electron lens is reelized by two different methods in this paper. One isdamped leastsquare method and the other is the artificial neural network method. Their merits and defects are discussed accordingto our calculation results in the psper. In the condition of selecting the learning samples properly, the artificial neuralnetwork has obvious advantages in the inverse design of electron lens. It is an effective method to solve the inversedesign problem in the electron optic system.

  3. Trade-offs between lens complexity and real estate utilization in a free-space multichip global interconnection module

    Science.gov (United States)

    Milojkovic, Predrag; Christensen, Marc P.; Haney, Michael W.

    2006-07-01

    The FAST-Net (Free-space Accelerator for Switching Terabit Networks) concept uses an array of wide-field-of-view imaging lenses to realize a high-density shuffle interconnect pattern across an array of smart-pixel integrated circuits. To simplify the optics we evaluated the efficiency gained in replacing spherical surfaces with aspherical surfaces by exploiting the large disparity between narrow vertical cavity surface emitting laser (VCSEL) beams and the wide field of view of the imaging optics. We then analyzed trade-offs between lens complexity and chip real estate utilization and determined that there exists an optimal numerical aperture for VCSELs that maximizes their area density. The results provide a general framework for the design of wide-field-of-view free-space interconnection systems that incorporate high-density VCSEL arrays.

  4. 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...

  5. Gabor lens theory

    International Nuclear Information System (INIS)

    The principle of using the space charge of an electron cloud to focus ion beams was first proposed by Gabor. Electrons are to be confined radially by means of an axial magnetic field B/sub z/ and axially by means of externally applied electric fields E/sub z/. An ion beam of charge density n/sub i/ much less than n/sub e/, the electron charge density can then be focused by the radial electric field set up by the electron cloud. The case considered here is that of a hollow cylindrical conductor charged to a potential +V with grounded rings on either side to set up the axial E/sub z/ field. A solenoid wound around the central conductor supplies the B/sub z/ field. Theoretical calculations are carried out for n/sub e/ maximum as a function of B/sub z/ due to radial confinement and V due to axial confinement and the focal length of the Gabor Lens is calculated

  6. Model-based calibration of an interferometric setup with a diffractive zoom-lens

    Science.gov (United States)

    Bielke, Alexander; Baer, Goran; Pruss, Christof; Osten, Wolfgang

    2015-08-01

    The fabrication of aspheres and freeform surfaces requires a high-precision shape measurement of these elements. In terms of accuracy, interferometric systems provide the best performance for specular surfaces. To test aspherical lenses, it is necessary to adapt or partially adapt the test wavefront to the surface under test. Recently, we have proposed an interferometric setup with a diffractive zoom-lens that includes two computer generated holograms for this purpose.1 Their surface phases are a combination of a cubic function for the adaption of aberrations and correction terms necessary to compensate substrate-induced errors. With this system based on Alvarez design a variable defocus and astigmatism controlled by a lateral shift of the second element is achieved. One of the main challenges is the calibration of the system. We use a black-box model2 recently introduced for a non-null test interferometer, the so called tilted wave interferometer3 (TWI). With it, the calibration data are calculated by solving an inverse problem. The system is divided in the two parts of illumination and imaging optics. By the solution of an inverse problem, we get a set of data, which describes separately the wavefronts of the illumination and imaging optics. The main difference to the TWI is the flexible diffractive element, which can be used in continuous positions. To combine the calibration data of a couple of positions with the exact placement, we designed alignment structures on the hologram. We will show the general functionality of this calibration and first simulation results.

  7. Investigation of error compensation in CGH-based form testing of aspheres

    Science.gov (United States)

    Stuerwald, S.; Brill, N.; Schmitt, R.

    2014-05-01

    Interferometric form testing using computer generated holograms is one of the main full-field measurement techniques. Till now, various modified measurement setups for optical form testing interferometry have been presented. Currently, typical form deviations in the region of several tens of nanometers occur in case of the widely used computer generated hologram (CGH) based interferometric form testing. Deviations occur due to a non-perfect alignment of the computer generated hologram (CGH) relative to the transmission sphere (Fizeau objective) and also of the asphere relative to the testing wavefront. Thus, measurement results are user and setup dependent which results in an unsatisfactory reproducibility of the form errors. In case of aligning a CGH, this usually requires a minimization of the spatial frequency of the fringe pattern by an operator. Finding the ideal position however often cannot be performed with sufficient accuracy by the operator as the position of minimum spatial fringe density is usually not unique. Therefore, the scientific and technical objectives of this paper comprise the development of a simulation based approach to explain and quantify the experimental errors due to misalignment of the specimen towards a computer generated hologram in an optical form testing measurement system. A further step is the programming of an iterative method to realize a virtual optimised realignment of the system on the basis of Zernike polynomial decomposition which should allow the calculation of the measured form for an ideal alignment and thus the subtraction of the alignment based form error. Different analysis approaches are investigated with regard to the final accuracy and reproducibility. To validate the theoretical models a series of systematic experiments is performed with hexapod-positioning systems in order to allow an exact and reproducible positioning of the optical CGH-based setup.

  8. Manufacture of aspherical molding dies for x-ray telescopes after ASTRO-H

    Science.gov (United States)

    Namba, Yoshiharu; Beaucamp, Anthony; Matsumoto, Hironori; Tamura, Keisuke; Tawara, Yuzuru; Kunieda, Hideyo; Takahashi, Tadayuki

    2014-07-01

    Producing X-ray imaging space telescopes is a very expensive endeavor, due in great part to the difficulty of fabricating thin mirrors for Wolter type-I optical assemblies. To meet this challenge, replication from optical molding dies (also called mandrels) has become the preferred method, as it is reliable and economical. Several replication methods exist: in the case of the ASTRO-H mission, DC magnetron sputtering was used to deposit Pt/C multilayer coating on glass molding dies. The multilayer coating was then bonded with epoxy to aluminum shells and then separated from the die. Another mirror replication method consists of slumping thin glass sheets over a full (or a section of) revolution molding die under high temperature. This method was demonstrated in the case of the NuSTAR mission. But the challenge of fabricating truly aspheric Wolter type molding dies, which are capable of highly accurate angular resolution (below 5 arcs), remains very expensive and time consuming. In this paper, three methods for producing X-ray optic molding dies are presented. Each method uses a different substrate material and process chain, as follows: electroless nickel plated aluminum (first diamond turned then correctively polished), fused silica (first precision ground then correctively polished), and CVD silicon carbide (which can be finished entirely with a newly developed Shape Adaptive Grinding process). The process chains employed for each method are explained in details, and their relative merits discussed. A way forward for the next generation of X-ray telescopes after ASTRO-H is then drawn out.

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

    International Nuclear Information System (INIS)

    We have developed compound refractive lenses (CRLs) for cold neutrons, which are made of vitreous silica and have an effective potential of (90.1-2.7x10-4i) 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

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

    International Nuclear Information System (INIS)

    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

  11. 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.

  12. Glass capillary X-ray lens: fabrication technique and ray tracing calculations

    International Nuclear Information System (INIS)

    A new method for producing a compound refractive X-ray lens is described. The lens is designed as glass capillary filled by a set of concave individual lenses. The method is appropriate for the preparation of 10-1000 spherical lenses in a glass capillary with a diameter of 0.1-1 mm. Lens aberrations are considered and simple formulas for spot size are derived. Ray-tracing simulations on the focusing experiments using 18 keV X-rays are reported

  13. 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.

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

    International Nuclear Information System (INIS)

    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.)

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

    Science.gov (United States)

    Kononenko, T. V.; Ralchenko, V. G.; Ashkinazi, E. E.; Polikarpov, M.; Ershov, P.; Kuznetsov, S.; Yunkin, V.; Snigireva, I.; Konov, V. I.

    2016-03-01

    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.

  17. Influence of the circumferential speed of a resin bond grinding wheel on the properties of a ground aspheric surface

    Czech Academy of Sciences Publication Activity Database

    Matoušek, O.; Tomka, David; Procháska, František; Polák, Jaroslav

    Vol. 9442. Bellingham: SPIE-INT SOC OPTICAL ENGINEERING, 2015 - (Kovačičinová, J.; Vít, T.), 94420T-94420T. (SPIE). ISBN 978-1-62841-557-5. ISSN 0277-786X. [Optics and Measurement Conference 2014 (OaM 2014). Liberec (CZ), 07.10.2014-10.10.2014] R&D Projects: GA MŠk(CZ) LO1206 Institutional support: RVO:61389021 Keywords : Aspheric grinding * resin bond * tool circumferential speed optimization Subject RIV: JP - Industrial Processing http://spie.org/Publications/Proceedings/Paper/10.1117/12.2175630

  18. REVIVAL OF THE STALLED CORE-COLLAPSE SUPERNOVA SHOCK TRIGGERED BY PRECOLLAPSE ASPHERICITY IN THE PROGENITOR STAR

    Energy Technology Data Exchange (ETDEWEB)

    Couch, Sean M. [Flash Center for Computational Science, Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Ott, Christian D., E-mail: smc@flash.uchichago.edu, E-mail: cott@tapir.caltech.edu [TAPIR, Mailcode 350-17, California Institute of Technology, Pasadena, CA 91125 (United States)

    2013-11-20

    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.

  19. 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.

  20. Lens system for SIMS analysis

    International Nuclear Information System (INIS)

    A powerful version of the charge-density method is applied to the study of a combined objective and emission lens, suitable for highly localized analysis of a flat sample surface. This lens can extract secondary ions of equal or opposite polarity to that of the primary particles. A computer simulation of the ion trajectories for both modes is made. The behaviour for different values of the geometric parameters and polarizations is analyzed and useful data for design such as primary beam demagnification and secondary image position are given. (author) 4 refs

  1. Broken intraocular lens during cataract surgery.

    OpenAIRE

    Kirkpatrick, J N; Cook, S D

    1992-01-01

    A case of planned routine extracapsular cataract extraction is described where surgery was complicated peroperatively by fracture of the posterior chamber lens implant. The technique of lens implantation is discussed.

  2. 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. PMID:27303797

  3. The Influence of the Aspheric Profiles for Transition Zone on Optical Performance of Human Eye After Conventional Ablation

    Science.gov (United States)

    Fang, L.

    2014-12-01

    The analysis in the impact of transition zone on the optical performance of human eye after laser refractive surgery is important for improving visual correction technology. By designing the ablation profiles of aspheric transition zone and creating the ablation profile for conventional refractive surgery in optical zone, the influence of aspheric transition zone on residual aberrations was studied. The results indicated that the ablation profiles of transition zone had a significant influence on the residual wavefront aberrations. For a hyperopia correction, the profile #9 shows a larger induced coma and spherical aberration when the translation of the centre of pupil remains constant. However, for a myopia astigmatism correction, the induced coma and spherical aberration in profile #1 shows relatively larger RMS values than those in other profiles. Therefore, the residual higher order aberrations may be decreased by optimizing ablation profiles of transition zone, but they cannot be eliminated. In order to achieve the best visual performance, the design of ablation pattern of transition zone played a crucial role.

  4. A broadband transformation-optics metasurface lens

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Xiang; Xiang Jiang, Wei; Feng Ma, Hui; Jun Cui, Tie, E-mail: tjcui@seu.edu.cn [State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096 (China)

    2014-04-14

    We present a transformational metasurface Luneburg lens based on the quasi-conformal mapping method, which has weakly anisotropic constitutive parameters. We design the metasurface lens using inhomogeneous artificial structures to realize the required surface refractive indexes. The transformational metasurface Luneburg lens is fabricated and the measurement results demonstrate very good performance in controlling the radiated surface waves.

  5. 21 CFR 886.3600 - Intraocular lens.

    Science.gov (United States)

    2010-04-01

    ... the natural lens of an eye. (b) Classification. Class III. (c) Date PMA or notice of completion of a... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraocular lens. 886.3600 Section 886.3600 Food... DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3600 Intraocular lens. (a) Identification....

  6. 21 CFR 886.1400 - Maddox lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Maddox lens. 886.1400 Section 886.1400 Food and... OPHTHALMIC DEVICES Diagnostic Devices § 886.1400 Maddox lens. (a) Identification. A Maddox lens is a device... intended to be handheld or placed in a trial frame to evaluate eye muscle dysfunction. (b)...

  7. Diabetes and contact lens wear.

    Science.gov (United States)

    O'Donnell, Clare; Efron, Nathan

    2012-05-01

    The literature suggests that diabetic patients may have altered tear chemistry and tear secretion as well as structural and functional changes to the corneal epithelium, endothelium and nerves. These factors, together with a reported increased incidence of corneal infection, suggest that diabetic patients may be particularly susceptible to developing ocular complications during contact lens wear. Reports of contact lens-induced complications in diabetic patients do exist, although a number of these reports concern patients with advanced diabetic eye disease using lenses on an extended wear basis. Over the past decade or so, there have been published studies documenting the response of the diabetic eye to more modern contact lens modalities. The results of these studies suggest that contact lenses can be a viable mode of refractive correction for diabetic patients. Furthermore, new research suggests that the measurement of tear glucose concentration could, in future, be used to monitor metabolic control non-invasively in diabetic patients. This could be carried out using contact lenses manufactured from hydrogel polymers embedded with glucose-sensing agents or nanoscale digital electronic technology. The purpose of this paper is to review the literature on the anterior ocular manifestations of diabetes, particularly that pertaining to contact lens wear. PMID:22537249

  8. Radiation damage of the lens

    International Nuclear Information System (INIS)

    Explained is the cataract as the lens is one of the most sensitive tissues to radiation, for considering the possible ophthalmological radiation disorder by the Fukushima Nuclear Power Plant Accident (2011). Radiation cataract is observed at 1-2 years after acute high dose exposure, but at low dose, it appears as the late effect. In fact, the disease related to exposure is found in as many as 25% of Chernobyl workers at >10 years post its Accident. Pathologic feature of radiation cataract has been thought to be the posterior subcapsular type. However, the cortical type is shown to be also noted by recent findings in the Chernobyl Accident, in the lens 30-45 years after radiotherapy of infants for dermovascular angioma, in astronaut, and in Hiroshima A-bomb survivors. Acute exposure to 0.5-1.5 Gy results in lens opacity and at >5 Gy, cataract with visual dysfunction. Higher cataract prevalence is recently reported seen in the therapeutic cardiac fluoroscopy where the medians of accumulated doses are 6.0 Sv in doctors and 1.5 Sv in nurses and radiologists. Astronauts exposed at >8 mSv have higher prevalence. Animal experiments have shown that the lens sensitivity to radiation depends on the age. Clinical experience of radiotherapy of the angioma above has suggested the higher sensitivity in young generation, which is supported by the fact that, among 114 inhabitants of 60Co-contaminated building, the dose effect is observable in 61 inhabitants of the age <20 y alone. linear threshold theory (LNT) hypothesis cannot be excluded by above evidences and there is conceivably no (or extremely low) threshold for cataract. The younger the age of exposure, the higher the risk of cataract, and thereby the lens in young generation should be carefully followed-up in Fukushima. (T.T.)

  9. 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

  10. Micro-optic lens for data storage

    Science.gov (United States)

    Milster, T. D.; Trusty, R. M.; Wang, M. S.; Froehlich, F. F.; Erwin, J. Kevin

    1991-01-01

    A new type of microlens for data storage applications that has improved off-axis performance is described. The lens consists of a micro Fresnel pattern on a curved substrate. The radius of the substrate is equal to the focal length of the lens. If the pattern and substrate are thin, the combination satisfies the Abbe sine condition. Therefore, the lens is free of coma. We analyze a 0.5 numerical aperture, 0.50 mm focal length lens in detail. A 0.16 numerical aperture lens was fabricated holographically, and results are presented.

  11. Lactate Dehydrogenase Isoenzyme of Lens in Fetus

    Institute of Scientific and Technical Information of China (English)

    Kexi Ding; Yasong Zhang

    2002-01-01

    Purpose: The LDH isoenzyme patterns were evaluated in lens of fetus to study the metabolism in human lenses.Methods: LDH isoenzyme electrophoresis was performed in 15 lenses of human fetus aged from 4~6 months.Results: There are 5 bands of LDH in fetus lens. LDH4 lever is the highest, and LDH1 is the lowest, especially in the cortex of lens. LDH1 is higher in lens of 4 months of age than in that of 5 and 6 months of age.Conclusions: LDH isoenzyme in lens of fetus shows mainly anaerobic metabolism in development, but there is also aerobic metabolism, especially in younger fetus.

  12. 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.

  13. Contact lens surface by electron beam

    International Nuclear Information System (INIS)

    Contact lens materials needs good biocompatibility, high refractive index, high optical transparency, high water content etc. Surface treat method by using plasma and radiation can modify the physical and/or chemical properties of the contact lens surface. Radiation technology such as electron beam irradiation can apply to polymerization reaction and enhance the functionality of the polymer.The purpose of this study is to modify of contact lens surface by using Eb irradiation technology. Electron beam was irradiated to the contact lens surface which was synthesized thermal polymerization method and commercial contact lens to modify physical and chemical properties. Ft-IR, XP, UV-vis spectrophotometer, water content, oxygen trans-metastability were used to characterize the surface state, physicochemical, and optical property of the contact lens treated with Eb. The water content and oxygen transmissibility of the contact lens treated with Eb were increased due to increase in the hydrophilic group such as O-C=O and OH group on the contact lens surface which could be produced by possible reaction between carbon and oxygen during the Eb irradiation. All of the lenses showed the high optical transmittance above 90%. In this case of B/Es, TES, Ti contact lens, the optical transmittance decreased about 5% with increasing Eb dose in the wavelength of UV-B region. The contact lens modified by Eb irradiation could improve the physical properties of the contact lens such as water content and oxygen transmissibility

  14. Contact lens surface by electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jung Hyuck [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Suk Ju; Hwang, Kwang Ha; Jeon Jin [Dongshin Univ., Naju (Korea, Republic of)

    2011-07-01

    Contact lens materials needs good biocompatibility, high refractive index, high optical transparency, high water content etc. Surface treat method by using plasma and radiation can modify the physical and/or chemical properties of the contact lens surface. Radiation technology such as electron beam irradiation can apply to polymerization reaction and enhance the functionality of the polymer.The purpose of this study is to modify of contact lens surface by using Eb irradiation technology. Electron beam was irradiated to the contact lens surface which was synthesized thermal polymerization method and commercial contact lens to modify physical and chemical properties. Ft-IR, XP, UV-vis spectrophotometer, water content, oxygen trans-metastability were used to characterize the surface state, physicochemical, and optical property of the contact lens treated with Eb. The water content and oxygen transmissibility of the contact lens treated with Eb were increased due to increase in the hydrophilic group such as O-C=O and OH group on the contact lens surface which could be produced by possible reaction between carbon and oxygen during the Eb irradiation. All of the lenses showed the high optical transmittance above 90%. In this case of B/Es, TES, Ti contact lens, the optical transmittance decreased about 5% with increasing Eb dose in the wavelength of UV-B region. The contact lens modified by Eb irradiation could improve the physical properties of the contact lens such as water content and oxygen transmissibility.

  15. Biomimetic accommodating lens with implementation in MEMS

    Science.gov (United States)

    Hogan, Alexander L.; Baker, Brian; Fisher, Charles; Naylor, Stephen; Fettig, Doug; Harvey, Ian R.

    2012-03-01

    We describe an accommodating lens patterned after the crystalline lens of the eye. Our biomimetic MEMS design calls to mind the zonules of zinn which pull radially to stretch the crystalline lens of the eye to modify the optical path. We present initial characterization of the prototype macro-scale device constructed through traditional machining techniques and using a PDMS polymer lens. Testing of the macro-scale lens indicated a 22% change in focal length through the range of radial stretching, with degradation of the spherical lens shape but no hysteresis after low-cycle testing. We also demonstrate a MEMS implementation of the lens actuator constructed using the Sandia SUMMiT-V ™ surface micromachining process. The optical path of this system is approximately 300 microns in diameter, providing a platform to potential applications improving mobile camera optics and medical imaging.

  16. MATTER MIXING IN ASPHERICAL CORE-COLLAPSE SUPERNOVAE: A SEARCH FOR POSSIBLE CONDITIONS FOR CONVEYING {sup 56}Ni INTO HIGH VELOCITY REGIONS

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Masaomi; Nagataki, Shigehiro; Ito, Hirotaka; Lee, Shiu-Hang; Mao, Jirong; Tolstov, Alexey [Astrophysical Big Bang Laboratory, RIKEN, Saitama 351-0198 (Japan); Hashimoto, Masa-aki, E-mail: masaomi.ono@riken.jp [Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan)

    2013-08-20

    We perform two-dimensional axisymmetric hydrodynamic simulations of matter mixing in aspherical core-collapse supernova explosions of a 16.3 M{sub Sun} star with a compact hydrogen envelope. Observations of SN 1987A have provided evidence that {sup 56}Ni synthesized by explosive nucleosynthesis is mixed into fast moving matter ({approx}>3500 km s{sup -1}) in the exploding star. In order to clarify the key conditions for reproducing such high velocity of {sup 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 find that no high velocity {sup 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 some unknown mechanism in a later phase just before the shock wave reaches the hydrogen envelope, {sup 56}Ni with a velocity of 3000 km s{sup -1} can be obtained. Aspherical explosions that are asymmetric across the equatorial plane with clumpy structures in the initial shock waves are investigated. We find that the clump sizes affect the penetration of {sup 56}Ni. Finally, we report that an aspherical explosion model that is asymmetric across the equatorial plane with multiple perturbations of pre-supernova origins can cause the penetration of {sup 56}Ni clumps into fast moving matter of 3000 km s{sup -1}. We show that both aspherical explosions with clumpy structures and perturbations of pre-supernova origins may be necessary to reproduce the observed high velocity of {sup 56}Ni. To confirm this, more robust three-dimensional simulations are required.

  17. Charting paths through gravity's lens

    International Nuclear Information System (INIS)

    Features of gravitational lenses are described, together with several examples of seemingly identical celestial objects which were later proved to be the same object. The first evidence was concerned with the object 0957+561, which featured two quasars 6 arcsec apart that displayed equal redshifts, magnitudes, and recession velocities, while the northern component exhibited 30 percent weaker emission and absorption. It was suggested that a galaxy interposed between the earth and a quasar was deflecting its emissions and causing it to be viewed as two distinct objects, i.e., a gravitational lens existed. Later evidence for the intervening galaxy was found, and also permitted attributing the anomalous redshift observed to a contribution from the galaxy. The light bending effect is predicted by the General Theory of Relativity, and is illustated in terms of a point mass, convex lens, and a galaxy

  18. Lens transglutaminase and cataract formation.

    OpenAIRE

    Lorand, L.; Hsu, L K; Siefring, G E; Rafferty, N S

    1981-01-01

    A protein polymer characteristically present in human cataract was shown to contain significant amounts of gamma-glutamyl-epsilon-lysine isopeptides. It is proposed that these crosslinks are produced by the action of transglutaminase (R-glutaminyl-peptide:amine-gamma-glutamyl-yltransferase, EC 2.3.2.13), which is all the more plausible because lens contains the enzyme and endogenous protein substrates for it. The enzyme is similar to that obtained from liver and is Ca2+ dependent. Highest app...

  19. 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.

  20. Fresnel Lens with Embedded Vortices

    OpenAIRE

    Sunil Vyas; Rakesh Kumar Singh; Devinder Pal Ghai; Senthilkumaran, P.

    2012-01-01

    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...

  1. Glycation precedes lens crystallin aggregation

    International Nuclear Information System (INIS)

    Non-enzymatic glycosylation (glycation) seems to have the potential to alter the structure of crystallins and make them susceptible to thiol oxidation leading to disulfide-linked high molecular weight (HMW) aggregate formation. They used streptozotocin diabetic rats during precataract and cataract stages and long-term cell-free glycation of bovine lens crystallins to study the relationship between glycation and lens crystallin aggregation. HMW aggregates and other protein components of the water-soluble (WS) and urea-soluble (US) fractions were separated by molecular sieve high performance liquid chromatography. Glycation was estimated by both [3H]NaBH4 reduction and phenylboronate agarose affinity chromatography. Levels of total glycated protein (GP) in the US fractions were about 2-fold higher than in the WS fractions and there was a linear increase in GP in both WS and US fractions. This increase was parallelled by a corresponding increase in HMW aggregates. Total GP extracted by the affinity method from the US fraction showed a predominance of HMW aggregates and vice versa. Cell-free glycation studies with bovine crystallins confirmed the results of the animals studies. Increasing glycation caused a corresponding increase in protein insolubilization and the insoluble fraction thus formed also contained more glycated protein. It appears that lens protein glycation, HMW aggregate formation, and protein insolubilization are interrelated

  2. Aging Changes of Lens Physical Properties

    Directory of Open Access Journals (Sweden)

    Kudryavtseva Y.V.

    2011-06-01

    Full Text Available The aim of the work is to assess aging changes of lens physical properties. Materials and Methods. There have been examined the patients aged 57—90 years. 73 lens nuclei with cataract of different maturity degree taken by means of extracapsular cataract extraction have been studied. Before the operation there has been determined relative echodensity of lens according to an original technique and assessed the lens colour and nuclear mass. Results. Brown colour of the lens nucleus is slightly increasing with years (r=0.4; р<0.05. Mean value of relative lens echodensity is 0.59±0.01. An average mass of lens nucleus is 98.3±1.0 mg, and its average density is 1312.0±12.0 mg/m2. Mature cataract is revealed to be not always hard (r=0.4; р<0.05, i.e. in this case the relation is inverse. When lens density increases, mechanical hardness of its nucleus grows up (r=0.4, р<0.05. At the same time mechanical density of lens nucleus increases with the increase of years (r=0.74, р<0.05. Age is stated not to be a controlling factor in cataract occurring and progressing. Conclusion. Lens mechanical characteristics depend on its chemical composition, and in aging brown colour of the lens increases, mechanical density of lens nucleus grows up, and vision can change slightly. Cataract maturation and the increase of lens density are chemically different processes and independent of each other.

  3. Adaptive liquid lens driven by elastomer actuator

    Science.gov (United States)

    Jin, Boya; Lee, Ji-Hyeon; Zhou, Zuowei; Zhang, Guoqing; Lee, Gi-Bbeum; Ren, Hongwen; Nah, Changwoon

    2016-01-01

    When a liquid droplet is filled in the hole of a dielectric elastomer (DE) film, a liquid lens is prepared. By applying a DC voltage to the DE film, the liquid lens can be actuated. As a comparison, two liquid lenses, one in a millimeter scale and the other in a submillimeter scale, are demonstrated. In a relaxed state, the focal length of each liquid lens is the longest. In an actuated state, the diameter of each lens is reduced. As a result, their focal length is tuned. Here, the DE film functions as an actuator. Due to the biconvex shape and smooth liquid surface, each liquid lens can provide good optical performance. They also possess the merits of simple fabrication, compact structure, and easy operation. In contrast to the bigger liquid lens, the smaller one can present a better mechanical stability without the concern of the gravitational effect.

  4. Laser differential confocal lens thickness measurement

    International Nuclear Information System (INIS)

    Based on the property that the absolute zero of an axial intensity curve exactly corresponds to the focus of the objective in a differential confocal system (DCS), a new laser differential confocal lens thickness measurement is proposed to achieve the high-precision non-contact measurement of lens thickness. The proposed approach uses the absolute zero of DCS axial response curve to precisely identify the vertexes of the test lens, obtains the central optical thickness of the test lens, and then uses the radius of curvature and refractive index of the test lens and the ray tracing facet iterative calculation to obtain the central geometrical thickness of the test lens. The theoretical analyses and preliminary experiments indicate that the measurement accuracy is better than 0.03%. (paper)

  5. Eye model with controllable lens scattering

    OpenAIRE

    Paeglis, R; Ozolinsh, M; Cikmacs, P; Andersson-Engels, Stefan

    2001-01-01

    A model of human eye for experiments in vision research has been developed using PLZT ceramics. This ``artificial eye{''} allows to simulate light scattering caused by cataract in the eye lens. Light scattering of a composite eye lens of the model depends on the electric field applied to a transparent electrooptic PLZT ceramics plate that is attached directly to the lens. The image degradation in such a model eye at various degrees of scattering is studied observing and recording the ...

  6. The lens and source of the optical Einstein ring gravitational lens ER 0047-2808

    OpenAIRE

    Wayth, Randall B.; Warren, Stephen J.; Lewis, Geraint F.; Hewett, Paul C.

    2004-01-01

    (Abridged) We perform a detailed analysis of the optical gravitational lens ER 0047-2808 imaged with WFPC2 on the Hubble Space Telescope. Using software specifically designed for the analysis of resolved gravitational lens systems, we focus on how the image alone can constrain the mass distribution in the lens galaxy. We find the data are of sufficient quality to strongly constrain the lens model with no a priori assumptions about the source. Using a variety of mass models, we find statistica...

  7. Role of Aquaporin 0 in lens biomechanics

    International Nuclear Information System (INIS)

    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

  8. Double-mirror peripheral vitrectomy lens.

    Science.gov (United States)

    Ohji, M; Tano, Y

    1995-11-01

    Many surgeons use prism lenses to see the periphery of the fundus during vitrectomy; however, chromatic aberrations in higher-power prismatic lenses cause blurring of the peripheral image. For better visualization of the periphery of the fundus, we developed a new contact lens, the double-mirror peripheral vitrectomy lens. The new lens is a quartz cylinder with two mirrors, and it provides a crisp, clear, upright image of much more of the peripheral fundus than is visible through conventional prism lenses. The new lens also provides a wider area of view than conventional prism lenses. PMID:7487611

  9. Stretchable Binary Fresnel Lens for Focus Tuning.

    Science.gov (United States)

    Li, Xueming; Wei, Lei; Poelma, René H; Vollebregt, Sten; Wei, Jia; Urbach, Hendrik Paul; Sarro, Pasqualina M; Zhang, Guo Qi

    2016-01-01

    This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material combines the excellent optical absorption properties of the CNT with the transparency and stretchability of the PDMS. By stretching the elastomeric composite in radial direction, the lens focal length is tuned. Good focusing response is demonstrated and a large focus change (≥24%) was achieved by stretching lenses up to 11.4%. PMID:27139747

  10. A Magnification Lens for Interactive Volume Visualization

    Energy Technology Data Exchange (ETDEWEB)

    LaMar, E; Hamann, B; Joy, K I

    2001-07-19

    Volume visualization of large data sets suffers from the same problem that many other visualization modalities suffer from: either one can visualize the entire data set and lose small details or visualize a small region and lose the context. In this paper, they present a magnification lens technique for volume visualization. While the notion of a magnification-lens is not new, and other techniques attempt to simulate the physical properties of a magnifying lens, their contribution is in developing a magnification lens that is fast, can be implemented using a fairly small software overhead, and has a natural, intuitive appearance. The issue with magnification lens is the border, or transition, region. The lens center and exterior have a constant zoom factor, and are simple to render. It is the border region that blends between the external and interior magnification, and has a non-constant magnification. They use the perspective-correct textures capability, available in most current graphics systems, to produce a lens with a tessellated border region that approximates linear compression with respect to the radius of the magnification lens. They discuss how a cubic border can mitigate the discontinuities resulting from the use of a linear function, without significant performance loss. They discuss various issues concerning development of a three-dimensional magnification lens.

  11. 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.

  12. Using of a microcapillary refractive X-ray lens for focusing and imaging

    International Nuclear Information System (INIS)

    The microcapillary lens, formed by air bubbles in a hollow core glass capillary filled with epoxy, is a novel design of a compound refractive lens for X-rays. The epoxy enclosed between two air bubbles has the form of a biconcave lens and acts as a positive lens for X-rays. Each individual lens is spherical with radius of curvature equal to the inner radius of the capillary. Up to 500 individual biconcave lenses can be formed in a single capillary with diameters from 50 to 500 μm. Due to the small radius of curvatures that can be achieved, microcapillary lenses typically have shorter focal lengths than those made by compression or injection molding. For example, microcapillary lenses with a focal length about 5 cm for 8 keV X-rays and 50-micron aperture are readily available. We have produced a set of lenses in a 200-micron inner-diameter glass capillary with 100-350 individual microlenses and measured their parameters at the Stanford Synchrotron Radiation Laboratory and at the Advanced Photon Source. Our investigations have also shown that the lenses are suitable for imaging applications with an X-ray tube as a source of X-rays. A simple X-ray microscope is discussed. The microscope consists of a copper anode X-ray tube, X-ray lens and CCD-camera. The object, lens and CCD-camera were placed in-line at distances to satisfy the lens formula. It is shown that the field of view of the microscope is about 1 mm and resolution is equal to 3-5 μm

  13. Phototoxicity and cytotoxicity of fullerol in human lens epithelial cells

    International Nuclear Information System (INIS)

    The water-soluble, hydroxylated fullerene [fullerol, nano-C60(OH)22-26] has several clinical applications including use as a drug carrier to bypass the blood ocular barriers. We have assessed fullerol's potential ocular toxicity by measuring its cytotoxicity and phototoxicity induced by UVA and visible light in vitro with human lens epithelial cells (HLE B-3). Accumulation of nano-C60(OH)22-26 in the cells was confirmed spectrophotometrically at 405 nm and cell viability estimated using MTS and LDH assays. Fullerol was cytotoxic to HLE B-3 cells maintained in the dark at concentrations higher than 20 μM. Exposure to either UVA or visible light in the presence of > 5 μM fullerol-induced phototoxic damage. When cells were pretreated with non-toxic antioxidants: 20 μM lutein, 1 mM N-acetyl cysteine, or 1 mM L-ascorbic acid prior to irradiation, only the singlet oxygen quencher-lutein significantly protected against fullerol photodamage. Apoptosis was observed in lens cells treated with fullerol whether or not the cells were irradiated, in the order UVA > visible light > dark. Dynamic light scattering (DLS) showed that in the presence of the endogenous lens protein α-crystallin, large aggregates of fullerol were reduced. In conclusion, fullerol is both cytotoxic and phototoxic to human lens epithelial cells. Although the acute toxicity of water-soluble nano-C60(OH)22-26 is low, these compounds are retained in the body for long periods, raising concern for their chronic toxic effect. Before fullerols are used to deliver drugs to the eye, they should be tested for photo- and cytotoxicity in vivo

  14. Spherical and aspherical photorefractive keratectomy and laser in-situ keratomileusis for moderate to high myopia: two prospective, randomized clinical trials. Summit technology PRK-LASIK study group.

    OpenAIRE

    Steinert, R F; Hersh, P S

    1998-01-01

    OBJECTIVE: Determine the outcomes of single-zone photorefractive keratectomy (SZPRK), aspherical photorefractive keratectomy (ASPRK), and laser in-situ keratomileusis (LASIK) for the correction of myopia between -6 and -12 diopters. DESIGN: Two simultaneous prospective, randomized, multi-center clinical trials. PARTICIPANTS: 286 first-treated eyes of 286 patients enrolled in one of two studies. In Study I, 134 eyes were randomized to SZPRK (58 eyes) or ASPRK (76 eyes). In Study II, 152 eyes w...

  15. Fabrication of Light Extraction Efficiency of Organic Light-Emitting Diodes with 3D Aspherical Microlens by Using Dry Etching Process

    OpenAIRE

    Chen, Y. C.; C. T. Pan; C. C. Hsieh; Su, C Y; Wu, H.C.; Li, W.C.

    2013-01-01

    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) w...

  16. Protection of the eye lens

    International Nuclear Information System (INIS)

    The limit of radiation exposure for eye lens is going to decrease dramatically from 150 to 20 mSv as a transposition into the French law of a CIPR (International Commission for Radiation Protection) directive. Sanitary studies have shown that radiologists are more likely by a factor of 3.8 to get eye lens opacities than the rest of the population. The wearing of protective glasses is recommended and in order to get a better monitoring of the radiation dose new dosimeters have been designed, they can be worn on the glass frame of directly stuck on the skin near the eyes. A study has shown that veterinary surgeons that are accustomed to stay near animals to keep them quiet during radiological exams are prone to receive high doses as well as physicians that use hypnosis to decrease the level of anxiety of their patients during radiological exams. Radiation exposure of radiologists can be mitigated through: the use of protective shields and equipment and the optimization of the dose delivered to the patient. (A.C.)

  17. Terminal lens for an FN tandem

    International Nuclear Information System (INIS)

    An electrostatic quadrupole triplet (ELQT) will be installed in the terminal of the Argonne FN tandem accelerator. The lens will be used in conjunction with foil stripping to maximize the transmission of heavy ions through the high-energy accelerator tube. The lens has steering capability and is controlled by a microcomputer located in the terminal

  18. Color corrected Fresnel lens for solar concentration

    International Nuclear Information System (INIS)

    A new linear convex Fresnel lens with its groove side down is described. The design philosophy is similar to the highly concentrating two focal Fresnel lens but including a correction for chromatic aberration. A solar concentration ratio as high as 80 is achieved. For wide acceptance angles the concentration nears the theoretical maximum. (author)

  19. Contact lens sensors in ocular diagnostics.

    Science.gov (United States)

    Farandos, Nicholas M; Yetisen, Ali K; Monteiro, Michael J; Lowe, Christopher R; Yun, Seok Hyun

    2015-04-22

    Contact lenses as a minimally invasive platform for diagnostics and drug delivery have emerged in recent years. Contact lens sensors have been developed for analyzing the glucose composition of tears as a surrogate for blood glucose monitoring and for the diagnosis of glaucoma by measuring intraocular pressure. However, the eye offers a wider diagnostic potential as a sensing site and therefore contact lens sensors have the potential to improve the diagnosis and treatment of many diseases and conditions. With advances in polymer synthesis, electronics and micro/nanofabrication, contact lens sensors can be produced to quantify the concentrations of many biomolecules in ocular fluids. Non- or minimally invasive contact lens sensors can be used directly in a clinical or point-of-care setting to monitor a disease state continuously. This article reviews the state-of-the-art in contact lens sensor fabrication, their detection, wireless powering, and readout mechanisms, and integration with mobile devices and smartphones. High-volume manufacturing considerations of contact lenses are also covered and a case study of an intraocular pressure contact lens sensor is provided as an example of a successful product. This Review further analyzes the contact lens market and the FDA regulatory requirements for commercialization of contact lens sensors. PMID:25400274

  20. Optimization of Zoom Lens with Discrete State of Liquid Lens Elements by Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Cheng-Mu Tsai

    2015-01-01

    Full Text Available This paper is to employ liquid lens elements to design a lens with zoom function by using the genetic algorithm (GA optimization. The liquid lens elements used in the proposal can apply voltage adjustment to generate the electrical field that induces the liquid with electric conductivity to vary the surface curvature between two different kinds of liquids. According to the voltage level, the liquid lens element makes the discrete variation of the curvature and thickness realize the zoom function without moving the lens groups so that the overall length can be reduced. However, it is difficult to design the zoom lens under the discrete variation of the curvature and thickness in the liquid lens elements and the mechanical space that is constantly limited. The GA offers a flexible way for lens optimization. We regarded the spot size as the fitness function to look for the optimum curvatures, thickness, and the corresponding statuses of liquid lens elements for the zoom lens. As a result, the zoom lens with constant space can be realized by running the selection, crossover, and mutation operation in the GA optimization.

  1. 非球面人工晶状体在个体化人眼模型中成像质量的研究%Optical quality of aspheric intraocular lenses in individual eye models

    Institute of Scientific and Technical Information of China (English)

    南莉; 汤欣; 刘永基

    2011-01-01

    Objective An aspheric intraocular lens (IOL) with fixed spherical aberration (SA) implanted in an individual patient will not always obtain ideal optical quality since human corneal structure and SA have large individual variations.The aim of this research was to study optical performance of individual pseudophakic eye models that were constructed based on individual anatomic parameters and implanted IOL with different optical designs.Methods Computer numerical simulation experiment.The anatomic parameters of individual pseudophakic patients were obtained by Pentacam and IOL Master.Parameters were input into ZEMAX to build individual eye models.Three aspheric IOL (SofPort AO,Tecnis Z9000,FY60AD) and one spherical IOL (YA60BBR) were implanted into individual eye models.Modulation transfer function (MTF) and contrast sensitivity function (CSF) were calculated for 3 mm to 5 mm pupil diameters and 550 nm wavelength.Results The height of the MTF and CSF curves were decreased with larger pupils.They were similar with the 4 IOL implanted in the individual eye models for 3 mm pupil diameter,but they were different from each other for 4 and 5 mm pupils,indicating that individual people with different anatomic structures need certain types of IOL to obtain optimal optical performance.This phenomenon was more pronounced for larger pupil.Conclusion The individual eye model based on an individual patient's anatomic parameters should mimic the optical performance of an individual's eye.The type of IOL is varied to obtain optimal optical performance for the optical system of the human eye with different anatomic structures.We should choose an IOL based on the individual eye's structure to obtain optimal retinal image clinically.%目的 根据不同患者眼部解剖参数建立个体化眼模型,研究植入不同设计的人工晶状体(IOL)后的光学表现.方法 计算机数字模拟实验.采用Pentacam眼前节分析系统、IOL Master采集白内障摘除联合IOL植入

  2. All-dielectric subwavelength metasurface focusing lens.

    Science.gov (United States)

    West, Paul R; Stewart, James L; Kildishev, Alexander V; Shalaev, Vladimir M; Shkunov, Vladimir V; Strohkendl, Friedrich; Zakharenkov, Yuri A; Dodds, Robert K; Byren, Robert

    2014-10-20

    We have proposed, designed, manufactured and tested low loss dielectric micro-lenses for infrared (IR) radiation based on a dielectric metamaterial layer. This metamaterial layer was created by patterning a dielectric surface and etching to sub-micron depths. For a proof-of-concept lens demonstration, we have chosen a fine patterned array of nano-pillars with variable diameters. Gradient index (GRIN) properties were achieved by engineering the nano-pattern characteristics across the lens, so that the effective optical density of the dielectric metamaterial layer peaks around the lens center, and gradually drops at the lens periphery. A set of lens designs with reduced reflection and tailorable phase gradients have been developed and tested, demonstrating focal distances of a few hundred microns, beam area contraction ratio up to three, and insertion losses as low as 11%. PMID:25401653

  3. Camera design of 4P slim 8 megapixel lens%4P超薄800万像素镜头设计

    Institute of Scientific and Technical Information of China (English)

    丛海芳

    2014-01-01

    针对手机镜头很难同时实现高成像质量和短总长的实际问题,通过对初始结构进行优化设计,得到一款全部采用光学塑料为透镜材料的超薄手机镜头。镜头采用四片式结构,光阑位于镜头前方,镜片全部采用偶次非球面。该镜头总长4.49 mm,F数为2.4,视场角为65.5°,焦距为3.71 mm,在探测器Nyquist频率处MTF均大于0.14,在半Nyquist频率处MTF均大于0.46,且畸变小于1.5%。光学系统各视场的均方根半径小于3.5μm。采用索尼公司的IMX111型号CMOS探测器,最大分辨率为3264×2448。通过模拟计算,得到该手机镜头的离焦量为144μm。通过调焦,可以在物距大于10 cm时,得到像质较好的图像。通过灵敏度分析,镜头公差满足加工要求。该镜头设计长度较短,采用非球面塑料透镜,生产成本较低,成像性能良好,满足手机镜头的使用要求。%To achieve good performance with short length, an ultra-thin cell phone lens was designed with optical plastic as lens material by optimizing the initial structure. The lens included four pieces with even aspheric, and the aperture was placed in front. The length of the lens was 4.49 mm, the F number was 2.4, the viewing angle was 65.5° , and the focal length was 3.71 mm. The MTF at the Nyquist frequency and half-Nyquist frequency of the detector was respectively greater than 0.14 and 0.46 and distortion of the lens was less than 1.5%. The RMS radius of different fields was less than 3.5μm. The CMOS sensor IMX111 from SONY was adopted, and the maximum resolution was 3 264 ×2 488. By simulation, the defocusing amount of the cell phone was 144μm. By focusing, high quality images can be obtained when the object distance was greater than 10 cm. Through the sensitivity analysis, the tolerance of the lens met the processing requirements. With short length and aspherical plastic lens, the production cost is low, the imaging

  4. Investigation of lens morphology and mechanical characteristics of lens capsule and lens nucleus in patients with agerelated and diabetic cataract

    Directory of Open Access Journals (Sweden)

    A. S. Tishkova

    2014-07-01

    Full Text Available Purpose: To investigate the influence of carbohydrate metabolism on the structure and mechanical properties of the lens capsule and nucleus.Methods: Human lens pathology was studied in different forms of cataract. 220 patients with a cataract (220 eyes were included in this study. Morphological, immunohystological and immunocytochemical investigations of lens substance (antibodies to a- (a-А and a-В, b-, g- crystallines, spectroscopic analyses of smears and morphometric analyses of slices, investigation of lens morphology and mechanical caracteristics of lens capsule and lens nucleus were performed.Results: The capsule of the lens in patients with senile cataract contains more Na+, Cl-. The capsule of the lens in patients with senile cataract contains more Ca2+, O. Mechanical strength of the capsule in the case of diabetes mellitus was lower comparatively with senile cataract in the same age groups. More significant expression of a-В and b-crystallines was found in patients with diabetes mellitus comparatively with patients with age-related cataract. Morphological features were founded in patients with cortical and nuclear forms of senile cataract and the diabetic cataract.Conclusion: During surgery (ultrasonic microcoaxial phacoemulsification the equivalent of ultrasound was recorded. Lower density of the lens nucleus of patients with diabetes mellitus made it possible to use lower energy parameters. Using the torsion ultrasound in those cases allowed us to decrease the influence of ultrasound on eye tissues and reduce the time of achieving the maximum BCVA in the postsurgical period.

  5. Explosive plane-wave lens

    Science.gov (United States)

    Marsh, Stanley P.

    1988-01-01

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive.

  6. 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.

  7. Accelerating convergence in automatic lens design

    International Nuclear Information System (INIS)

    Among the various factors that slow lens optimization-insufficient performance targets, the absence of a unique solution, false local minima, a poorly scaled change vector, failure to find the optimum damping number, and failure to equalize the parameter gradients-the importance of parameter gradient equalization has been insufficiently recognized. Gradients can be approximately equalized by scaling the lens to a suitable size while it is being optimized. For best results, the size of the damping number should also be optimized during each iteration. If these two procedures are followed, scaling the change vector is usually not crucial. To illustrate the importance of parameter equalization, a lens optimization is analyzed

  8. Fresnel lens solar beam convergence properties

    Science.gov (United States)

    Huang, Minshuang; Tian, Feng

    2014-11-01

    Use the law of refraction of light for theoretical analysis of sunlight incident Fresnel lens, summary of the relationship between Fresnel lens solar light beam convergence characteristics and beam incident angle,beam incident position.Through the analysis of the calculation and experimental, to obtain a variety of incident angle lens center and best gathering focal spot the size of the data.Discuss the incident angle, incident location,the relationship between convergence center and focal spot size.For the sun acquisition system of the light from the sun and optical fiber coupling design do sufficient theory design basis.

  9. 21 CFR 886.1390 - Flexible diagnostic Fresnel lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Flexible diagnostic Fresnel lens. 886.1390 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1390 Flexible diagnostic Fresnel lens. (a) Identification. A flexible diagnostic Fresnel lens is a device that is a very thin lens which...

  10. 16 CFR 315.6 - Expiration of contact lens prescriptions.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Expiration of contact lens prescriptions... CONGRESS CONTACT LENS RULE § 315.6 Expiration of contact lens prescriptions. (a) In general. A contact lens... Commission, its employees, and its representatives. (3) No prescriber shall include an expiration date on...

  11. Luneburg and flat lens based on graded photonic crystal

    Science.gov (United States)

    Liu, Wei; Sun, Xiaohong; Gao, Minglei; Wang, Shuai

    2016-04-01

    Square-lattice graded photonic crystals employed for designing Luneburg and Flat Lens is presented. Comparable simulation of the Luneburg lens with TE and TM polarizations predicts that TM lens possesses of enlarged transmission bandwidth and strengthened focusing ability, in comparison with TE lens. As a typical simplified counterpart, the evolution of focusing intensity and numerical aperture of the flat lens is achieved. What is more, those Luneburg and Flat Lens can withstand imperfect gradients in structure design. This will provide a guidance to produce a high quality focusing lens with small size, short focal length and large numerical aperture applied in the integrated photonic devices.

  12. 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.

  13. RISK FACTORS FOR CONTACT LENS INDUCED PAPILLARY CONJUNCTIVITIS ASSOCIATED WITH SILICONE HYDROGEL CONTACT LENS WEAR

    Science.gov (United States)

    Tagliaferri, Angela; Love, Thomas E.; Szczotka-Flynn, Loretta

    2014-01-01

    BACKGROUND Contact lens induced papillary conjunctivitis (CLPC) continues to be a major cause of dropout during contact lens extended wear. This retrospective study explores risk factors for the development of CLPC during silicone hydrogel lens extended wear. METHODS Data from 205 subjects enrolled in the Longitudinal Analysis of Silicone Hydrogel Contact Lens (LASH) study wearing lotrafilcon A silicone hydrogel lenses for up to 30 days of continuous wear were used to determine risk factors for CLPC in this secondary analysis of the main cohort. The main covariates of interest included substantial lens-associated bacterial bioburden, and topographically determined lens base curve-to-cornea fitting relationships. Additional covariates of interest included history of prior adverse events, time of year, race, education level, gender and other subject demographics. Statistical analyses included univariate logistic regression to assess the impact of potential risk factors on the binary CLPC outcome, and Cox proportional hazards regression to describe the impact of those factors on time-to-CLPC diagnosis. RESULTS Across 12 months of follow-up, 52 subjects (25%) experienced CLPC. No associations were found between CLPC development and the presence of bacterial bioburden, lens-to-cornea fitting relationships, history of prior adverse events, gender or race. CLPC development followed the same seasonal trends as the local peaks in environmental allergans. CONCLUSIONS Lens fit and biodeposits, in the form of lens associated bacterial bioburden, were not associated with the development of CLPC during extended wear with lotrafilcon A silicone hydrogel lenses. PMID:24681609

  14. Measurement of Crystalline Lens Volume During Accommodation in a Lens Stretcher

    Science.gov (United States)

    Marussich, Lauren; Manns, Fabrice; Nankivil, Derek; Maceo Heilman, Bianca; Yao, Yue; Arrieta-Quintero, Esdras; Ho, Arthur; Augusteyn, Robert; Parel, Jean-Marie

    2015-01-01

    Purpose To determine if the lens volume changes during accommodation. Methods The study used data acquired on 36 cynomolgus monkey lenses that were stretched in a stepwise fashion to simulate disaccommodation. At each step, stretching force and dioptric power were measured and a cross-sectional image of the lens was acquired using an optical coherence tomography system. Images were corrected for refractive distortions and lens volume was calculated assuming rotational symmetry. The average change in lens volume was calculated and the relation between volume change and power change, and between volume change and stretching force, were quantified. Linear regressions of volume-power and volume-force plots were calculated. Results The mean (±SD) volume in the unstretched (accommodated) state was 97 ± 8 mm3. On average, there was a small but statistically significant (P = 0.002) increase in measured lens volume with stretching. The mean change in lens volume was +0.8 ± 1.3 mm3. The mean volume-power and volume-load slopes were −0.018 ± 0.058 mm3/D and +0.16 ± 0.40 mm3/g. Conclusions Lens volume remains effectively constant during accommodation, with changes that are less than 1% on average. This result supports a hypothesis that the change in lens shape with accommodation is accompanied by a redistribution of tissue within the capsular bag without significant compression of the lens contents or fluid exchange through the capsule. PMID:26161985

  15. Minus Piggyback Lens Overlaying ReSTOR® Multifocal Lens in High Myopia

    OpenAIRE

    Gupta, Isha; Oakey, Zack; Stagg, Brian C; Ambati, Balamurali K.

    2013-01-01

    Background We report the case of a 40-year-old female patient treated with implantation of the Acrysof® IQ ReSTOR® lens (Alcon, Fort Worth, Tex., USA) with overlaying Acrysof EXpand® minus piggyback lens (Alcon). Methods The patient had high myopia and was diagnosed with presbyopia and bilateral posterior subcapsular cataract. She desired to be spectacle-free and opted to undergo bilateral placement of the ReSTOR multifocal lens. The necessary intraocular lens (IOL) power was +3.5 in the righ...

  16. 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

  17. Characteristics of soft X-ray lens

    International Nuclear Information System (INIS)

    A soft X-lens was devised with waveguide X-ray optics of total external reflection (TER). The lens consists of a stack of 1 387 TER waveguides with inner diameter of 0.45 mm and outer diameter of 0.60 mm. With the help of plasma sources of soft X-ray radiation, high density of pure soft X-ray radiation (without plasma expansion fragments) with broad-band spectral range can be obtained at the focus of the lens. As laser-plasma is considered, the radiation density of 1.3 x 105 W/cm2 is obtained, the transmission coefficient is 18.6%, the ratio of the density at the focus with and without the lens is 1000 and the radiation capture is 28.9 degree. The density of 0.5 TW/cm2 can be obtained as far as Qiang-Guang I facility is considered. (authors)

  18. Adaptive lens using liquid crystal concentration redistribution

    Science.gov (United States)

    Ren, Hongwen; Lin, Yi-Hsin; Wu, Shin-Tson

    2006-05-01

    An adaptive lens using electrically induced liquid crystal (LC)/monomer concentration redistribution is demonstrated. In the absence of an electric field, the LC/monomer mixture is homogeneously distributed. Application of an inhomogeneous electric field causes the LC molecules to diffuse towards the high field region and the liquid monomer towards the low field region. On the other hand, the LC molecules tend to diffuse from high to low concentration direction in order to balance the concentration change. A gradient LC concentration is thus obtained. Using the gradient LC concentration, we demonstrate a tunable-focus lens. Compared with a conventional LC lens, our lens has advantages in small astigmatism and without light scattering, but its response time is slower.

  19. Methane Detector With Plastic Fresnel Lens

    Science.gov (United States)

    Grant, W. B.

    1986-01-01

    Laser detector for natural gas leaks modified by substitution of molded plastic lens for spherical mirror. By measuring relative attenuation at two wavelengths, detector used to check for methane escaping from pipelines above or below ground and from landfill.

  20. 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

  1. Autophagy and mitophagy participate in ocular lens organelle degradation

    OpenAIRE

    Costello, M Joseph; Brennan, Lisa A.; Basu, Subharsee; Chauss, Daniel; Mohamed, Ashik; Gilliland, Kurt O.; Johnsen, Sönke; Menko, Sue; Kantorow, Marc

    2013-01-01

    The eye lens consists of a layer of epithelial cells that overlay a series of differentiating fiber cells that upon maturation lose their mitochondria, nuclei and other organelles. Lens transparency relies on the metabolic function of mitochondria contained in the lens epithelial cells and in the immature fiber cells and the programmed degradation of mitochondria and other organelles occurring upon lens fiber cell maturation. Loss of lens mitochondrial function in the epithelium or failure to...

  2. 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.

  3. 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.

  4. In vivo human crystalline lens topography

    OpenAIRE

    Sergio Ortiz; Pablo P\\xe9rez-Merino; Enrique Gambra; Alberto de Castro; Susana de Marcos

    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 ...

  5. Periocular migration of an intraocular lens.

    OpenAIRE

    Jenkins, C.

    1992-01-01

    A woman presented with a painful eye 6 weeks after cataract extraction and intraocular lens implantation. In the past she had had a sector iridectomy for iris bombé caused by chronic anterior uveitis. On examination the three central corneal sutures were absent, whilst the medial and lateral sutures had broken and were protruding from the section. The eye was quiet and the section intact. Combined clinical and ultrasound examination failed to locate the intraocular lens. Four months postopera...

  6. 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.

  7. Multipurpose soft contact lens care in Japan

    OpenAIRE

    Toshida H; Kadota Y; Suto C; Ohta T; Murakami A

    2012-01-01

    Hiroshi Toshida1,2, Yoshiaki Kadota3, Chikako Suto2, Toshihiko Ohta1, Akira Murakami21Juntendo University Shizuoka Hospital, Department of Ophthalmology, Shizuoka, 2Juntendo University School of Medicine, Department of Ophthalmology, Tokyo, 3Bausch & Lomb Japan Co, Ltd, Research and Development, Tokyo, JapanPurpose: To assess the use of multipurpose lens care products via an online survey conducted among soft contact lens (SCL) wearers in Japan.Methods: The subjects were 1000 men and ...

  8. Fresnel Lens Sidewall Design for Imaging Optics

    Science.gov (United States)

    Fujii, T.; Goulet, A.; Hattori, K.; Konno, K.; Tanaka, A.; Bosmans, R.; Sawada, M.; Yazawa, H.

    2015-03-01

    We developed a ray tracing simulation tool for imaging systems including a Fresnel lens with a quasi-arbitrary sidewall structure. One issue with Fresnel lens is that noise in the image plane can appear from rays passing through or reflected at its sidewalls. One way to reduce it is to modify the orientation of the sidewalls so that rays will not reach the image plane. To find the best sidewall orientations, we developed a method where locally, a sidewall can freely be oriented. We could then derive the best modulation scheme for each Fresnel lens sidewall. In the case of a single imaging Fresnel lens, relative parasite noise intensity could mostly be prevented. To experimentally check our method, snapshot images were taken with single Fresnel lenses and a single spherical lens. No noticeable differences in image quality could be observed using a standard C-MOS camera. However, parasite noise could experimentally be detected with a Fresnel lens prototype when using a very! high-dynamic range C-MOS camera.

  9. Acoustic lens for capacitive micromachined ultrasonic transducers

    International Nuclear Information System (INIS)

    Capacitive micromachined ultrasonic transducers (CMUTs) have great potential to compete with traditional piezoelectric transducers in therapeutic ultrasound applications. In this paper we have designed, fabricated and developed an acoustic lens formed on the CMUT to mechanically focus ultrasound. The acoustic lens was designed based on the paraxial theory and made of silicone rubber for acoustic impedance matching and encapsulation. The CMUT was fabricated based on the local oxidation of silicon (LOCOS) and fusion-bonding. The fabricated CMUT was verified to behave like an electromechanical resonator in air and exhibited wideband response with a center frequency of 2.2 MHz in immersion. The fabrication for the acoustic lens contained two consecutive mold castings and directly formed on the surface of the CMUT. Applied with ac burst input voltages at the center frequency, the CMUT with the acoustic lens generated an output pressure of 1.89 MPa (peak-to-peak) at the focal point with an effective focal gain of 3.43 in immersion. Compared to the same CMUT without a lens, the CMUT with the acoustic lens demonstrated the ability to successfully focus ultrasound and provided a viable solution to the miniaturization of the multi-modality forward-looking endoscopes without electrical focusing. (paper)

  10. 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.

  11. 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

  12. 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.

  13. 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. PMID:26367912

  14. 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...

  15. Off-axis aspheric surface measurement by coordinate contour measuring machine%离轴非球面三坐标检测技术

    Institute of Scientific and Technical Information of China (English)

    陈曦; 郭培基; 王建明; 仇谷烽

    2014-01-01

    A method is proposed to measure off-axis aspherical mirrors with a circular flat base,a rectangular flat base and a family of parallel lines that cut the circular flat base by a coordinate measurement machine (CMM).In re-sponse to the base features above,workpiece coordinate system is designed,and the positioning points used to establish the workpiece coordinate system are defined.The 3D-coordinates point-cloud data on the off-axis mirrors are obtained with automatic measurement of single points schema by CMM,and then,the off-axis aspheric surface data processing model for these error corrections is built.Compared with the data by the theoretical model,the surface error of an actual off-axis aspheric surface is obtained.All the pre-polishing processes are guided according to the measurement results.%提出了一种使用三坐标测量机(CMM)测量底面为圆形、矩形、跑道形离轴非球面面形误差的方法。针对离轴非球面的外形特征设计工件坐标系,规划工件坐标系定位点;利用CMM对离轴非球面进行点触发式自动测量,得到被测面点云坐标数据;建立离轴非球面数据处理模型,得出了面形误差。模拟分析表明,该测试方法和误差处理模型是正确的,并用该检测技术完成了离轴非球面粗抛光阶段的加工。

  16. Contrast sensitivity and spherical aberration in eyes implanted with AcrySof IQ and AcrySof Natural intraocular lens: the results of a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Jianping Liu

    Full Text Available BACKGROUND: To systematically evaluate the visual performance of aspheric AcrySof IQ and spherical AcrySof Natural intraocular lens (IOL after cataract surgery. METHODOLOGY/PRINCIPAL FINDINGS: Potential randomized controlled trials (RCTs that involved implanting AcrySof IQ and AcrySof Natural were searched from PubMed, Web of science, EMBASE, Chinese Science and Technology Periodicals Databases and Cochrane Central Register of Controlled Trials. The methodological quality of the studies was assessed by the Jadad method. Standardized mean differences (SMDs with 95% confidence intervals (CIs of best-corrected visual acuity (BCVA, contrast sensitivity and spherical aberration were pooled using a random-effects model. Seven studies were identified and analyzed to compare AcrySof IQ (236 eyes with AcrySof Natural (232 eyes after phacoemulsification. There was no significant difference in postoperative BCVA between AcrySof IQ and AcrySof Natural (p =0.137 after a follow up of 3 months. For contrast sensitivity, these differences reached statistical significance under photopic conditions at two spatial frequencies (3 cycles per degree (cpd, 6 cpd, 12 cpd, and 18 cpd; p =0.022, p =0.017, p = 0.065, and p=0.191, respectively and under mesopic conditions at three spatial frequencies (3 cpd, 6 cpd, 12 cpd, and 18 cpd; p =0.007, p =0.033, p =0.030, and p =0.080, respectively. Eyes with AcrySof IQ also had statistically significant less spherical aberration than eyes with AcrySof Natural (p<0.001. Sensitivity analysis showed that the results were relatively stable and reliable. CONCLUSIONS/SIGNIFICANCE: The overall findings indicate that AcrySof IQ with a modified aspheric surface induced significantly less spherical aberration than AcrySof Natural. Contrast sensitivity in eyes with AcrySof IQ is better than that in eyes with AcrySof Natural, especially under mesopic conditions.

  17. 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.

  18. 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

  19. Optical integration of Pancharatnam-Berry phase lens and dynamical phase lens

    Science.gov (United States)

    Ke, Yougang; Liu, Yachao; Zhou, Junxiao; Liu, Yuanyuan; Luo, Hailu; Wen, Shuangchun

    2016-03-01

    In the optical system, most elements such as lens, prism, and optical fiber are made of silica glass. Therefore, integrating Pancharatnam-Berry phase elements into silica glass has potential applications in the optical system. In this paper, we take a lens, for example, which integrates a Pancharatnam-Berry phase lens into a conventional plano-convex lens. The spin states and positions of focal points can be modulated by controlling the polarization states of the incident beam. The proposed lens has a high transmission efficiency, and thereby acts as a simple and powerful tool to manipulate spin photons. Furthermore, the method can be conveniently extended to the optical fiber and laser cavity, and may provide a route to the design of the spin-photonic devices.

  20. Human lens coloration and aging. Evidence for crystallin modification by the major ultraviolet filter, 3-hydroxy-kynurenine O-beta-D-glucoside.

    Science.gov (United States)

    Hood, B D; Garner, B; Truscott, R J

    1999-11-12

    The human lens becomes increasingly yellow with age and thereby reduces our perception of blue light. This coloration is associated with lens proteins (crystallins), but its molecular basis was unknown. Here we show that the coloration occurs because of the interaction of crystallins with a UV filter compound, 3-hydroxykynurenine glucoside (3-OHKG). Crystallin modification results from deamination of the 3-OHKG amino acid side chain, yielding an unsaturated ketone that is susceptible to nucleophilic attack by cysteine, histidine, and lysine residues. This novel protein modification contributes to age-related lens coloration and may play a role in human nuclear cataractogenesis. PMID:10551806

  1. Models of the Cosmic Horseshoe Gravitational Lens

    CERN Document Server

    Dye, Simon; Belokurov, V; Warren, S J; Hewett, P

    2008-01-01

    We model the extremely massive and luminous lens galaxy in the Cosmic Horseshoe Einstein ring system, recently discovered in the Sloan Digital Sky Survey. We use the semi-linear method of Warren & Dye (2003), which pixelises the source surface brightness distribution, to invert the Einstein ring for sets of parameterised lens models. Here, the method is refined by exploiting Bayesian inference to optimise adaptive pixelisation of the source plane and to choose between three differently parameterised models: a singular isothermal ellipsoid, a power law model and a NFW profile. The most probable lens model is the power law with a volume mass density that scales as r^(-1.96+/-0.02) and an axis ratio of ~0.8. The mass within the Einstein ring (i.e., within a cylinder with projected distance of ~30 kpc from the centre of the lens galaxy) is (5.02+/-0.09)*10^12 M_solar, and the mass-to-light ratio is ~30. Even though the lens lies in a group of galaxies, the preferred value of the external shear is almost zero....

  2. Parametric modeling of zoom lens barrels

    Science.gov (United States)

    Pierce, Charles W.

    2001-12-01

    Today's customer requires zoom lens designs that are compact, inexpensive, and at six-sigma quality levels. While incorporating these customer requirements, a design team must often work within compressed design cycles and minimal product development budgets. These customer and project constraints, coupled with the inherent complexity of a zoom lens module, force the design team to try new and innovative techniques to deliver their products. This paper presents the methods used to develop lens barrels for several zoom lens module projects at Eastman Kodak Company. The lens barrel, a critical interface between the mechanical and optical systems, presented a technical barrier from both an engineering analysis and manufacturing perspective. The method used to overcome these barriers consisted of identifying several key functional parameters, creating a parameter-driven 3-D solid model in a commercially available CAD system, and then using the model to make iterative, data-driven design decisions while leveraging the model to create engineering drawings and the necessary prototypes and production tooling. As a result, the designs were able to meet their size, cost, and design cycle time requirements while realizing a better than anticipated first pass yield and quality level.

  3. Efficient flat metasurface lens for terahertz imaging.

    Science.gov (United States)

    Yang, Quanlong; Gu, Jianqiang; Wang, Dongyang; Zhang, Xueqian; Tian, Zhen; Ouyang, Chunmei; Singh, Ranjan; Han, Jiaguang; Zhang, Weili

    2014-10-20

    Metamaterials offer exciting opportunities that enable precise control of amplitude, polarization and phase of the light beam at a subwavelength scale. A gradient metasurface consists of a class of anisotropic subwavelength metamaterial resonators that offer abrupt amplitude and phase changes, thus enabling new applications in optical device design such as ultrathin flat lenses. We propose a highly efficient gradient metasurface lens based on a metal-dielectric-metal structure that operates in the terahertz regime. The proposed structure consists of slotted metallic resonator arrays on two sides of a thin dielectric spacer. By varying the geometrical parameters, the metasurface lens efficiently manipulates the spatial distribution of the terahertz field and focuses the beam to a spot size on the order of a wavelength. The proposed flat metasurface lens design is polarization insensitive and works efficiently even at wide angles of incidence. PMID:25401626

  4. Freeform micromachining of an infrared Alvarez lens

    Science.gov (United States)

    Smilie, Paul J.; Dutterer, Brian S.; Lineberger, Jennifer L.; Davies, Matthew A.; Suleski, Thomas J.

    2011-02-01

    In 1967, Luis Alvarez introduced a novel concept for a focusing lens whereby two transmitting elements with cubic polynomial surfaces yield a composite lens of variable focal length with small lateral shifts. Computer simulations have demonstrated the behavior of these devices, but fabricating the refractive cubic surfaces of the types needed with adequate precision and depth modulation has proven to be challenging using standard methods, and, to the authors' knowledge, Alvarez lens elements have not been previously machined in infrared materials. Recent developments in freeform diamond machining capability have enabled the fabrication of such devices. In this paper, we discuss the fabrication of freeform refractive Alvarez elements in germanium using diamond micro-milling on a five-axis Moore Nanotech® 350FG Freeform Generator. Machining approaches are discussed, and measurements of surface figure and finish are presented. Initial experimental tests of optical performance are also discussed.

  5. 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...

  6. 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...... the skull base. Conclusion: These results indicate that it is possible to reduce the radiation dose to the eye lens without loss of diagnostic information in the scan by optimizing positioning of the head....

  7. 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.

  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. Catadioptric aberration correction in cathode lens microscopy

    International Nuclear Information System (INIS)

    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

  10. Laser light scattering in eye lens model

    Science.gov (United States)

    Larionova, Nadezhda L.; Maksimova, Irina L.; Kochubey, Vyacheslav I.

    2000-11-01

    Theoretical investigations of laser light radiation scattered by eye lens model as a system of spheres with various parameters were performed on the base of Mie theory of electromagnetic scattering by a single sphere. The calculations were performed for systems of particles whose coordinates were specifically realized in random fashion according to the specified probabilities defined by the approximation of hard spheres. The modeling of lens biotissue was carried out by using of medical data about internal structure of lens of human and some animals. In general the researchable model presents the system of homogeneous spherical particles those are randomly distributed in the layer of thickness. We study the optical properties such as scattering effective cross-section and function of correlation in different models.

  11. Eye lens dose in interventional cardiology.

    Science.gov (United States)

    Principi, S; Delgado Soler, C; Ginjaume, M; Beltran Vilagrasa, M; Rovira Escutia, J J; Duch, M A

    2015-07-01

    The ICRP has recently recommended reducing the occupational exposure dose limit for the lens of the eye to 20 mSv y(-1), averaged over a period of 5 y, with no year exceeding 50 mSv, instead of the current 150 mSv y(-1). This reduction will have important implications for interventional cardiology and radiology (IC/IR) personnel. In this work, lens dose received by a staff working in IC is studied in order to determine whether eye lens dose monitoring or/and additional radiological protection measures are required. Eye lens dose exposure was monitored in 10 physicians and 6 nurses. The major IC procedures performed were coronary angiography and percutaneous transluminal coronary angioplasty. The personnel were provided with two thermoluminescent dosemeters (TLDs): one calibrated in terms of Hp(3) located close to the left ear of the operator and a whole-body dosemeter calibrated in terms of Hp(10) and Hp(0.07) positioned on the lead apron. The estimated annual eye lens dose for physicians ranged between 8 and 60 mSv, for a workload of 200 procedures y(-1). Lower doses were collected for nurses, with estimated annual Hp(3) between 2 and 4 mSv y(-1). It was observed that for nurses the Hp(0.07) measurement on the lead apron is a good estimate of eye lens dose. This is not the case for physicians, where the influence of both the position and use of protective devices such as the ceiling shield is very important and produces large differences among doses both at the eyes and on the thorax. For physicians, a good correlation between Hp(3) and dose area product is shown. PMID:25809107

  12. 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.

  13. Eye lens dose in interventional cardiology

    International Nuclear Information System (INIS)

    The ICRP has recently recommended reducing the occupational exposure dose limit for the lens of the eye to 20 mSv y-1 , averaged over a period of 5 y, with no year exceeding 50 mSv, instead of the current 150 mSv y-1 . This reduction will have important implications for interventional cardiology and radiology (IC/IR) personnel. In this work, lens dose received by a staff working in IC is studied in order to determine whether eye lens dose monitoring or/and additional radiological protection measures are required. Eye lens dose exposure was monitored in 10 physicians and 6 nurses. The major IC procedures performed were coronary angiography and percutaneous transluminal coronary angioplasty. The personnel were provided with two thermoluminescent dosemeters (TLDs): one calibrated in terms of Hp(3) located close to the left ear of the operator and a whole-body dosemeter calibrated in terms of Hp(10) and Hp(0.07) positioned on the lead apron. The estimated annual eye lens dose for physicians ranged between 8 and 60 mSv, for a workload of 200 procedures y-1. Lower doses were collected for nurses, with estimated annual Hp(3) between 2 and 4 mSv y-1. It was observed that for nurses the Hp(0.07) measurement on the lead apron is a good estimate of eye lens dose. This is not the case for physicians, where the influence of both the position and use of protective devices such as the ceiling shield is very important and produces large differences among doses both at the eyes and on the thorax. For physicians, a good correlation between Hp(3) and dose area product is shown. (authors)

  14. Sterilization potential of contact lens solutions

    Directory of Open Access Journals (Sweden)

    Dada Vijay

    1988-01-01

    Full Text Available In a dynamic field of Contact Lens Solutions maintenance of high standards of anti-microbial activity is a must Resterilization Activity Time′ is a universally accepted yardstick for such an evaluation. In this study eight brands of indigenous popular solutions alongwith two FDA approved solutions were tested for their sterilization efficacy: Standardized suspensions of Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus fumigatus were used for the purpose. It was observed that the contact lens solutions available ir, the domestic market were not upto the mark Suggestions for improvement have also been made.

  15. Near field imaging from multilayer lens.

    Science.gov (United States)

    Li, Guixin; Li, Jensen; Tam, H L; Chan, C T; Cheah, K W

    2011-12-01

    Multilayer superlens has been reported that it had advantages over the single metal layer superlens. In this work, single silver layer and Ag-SiO2 multilayer superlens devices working at wavelength of 365 nm were fabricated using standard photolithography method. Grating objects with line/space (190 nm/190 nm) resolution could be resolved through both kinds of lens structures with working distance up to 128 nm. However, Ag-SiO2 multilayer lens shows higher transmittance and image contrast than the single silver layer device, the experimental result proves the theoretical calculation. PMID:22408982

  16. Fabrication of an unusual mosaic lens

    International Nuclear Information System (INIS)

    The design philosophy and the construction techniques to make a novel mosaic lens to collect Cerenkow radiation are described. The lens blanks were rough cut into segments by a water jet. The segments were cut to the final inner and outer diameters by ultrasonically assisted machining, an unusual new technique developed at the Los Alamos National Laboratory. The technology will soon be available to the public through Sonic Mill, Inc., 3820 Academy Parkway North, NE, Albuquerque, N.M. 87109. The advantage of ultrasonically assisted machining lies in rapid, accurate shaping of brittle materials such as ceramics and glass, which can by this technique, be shaped about as fast as aluminum

  17. 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).

  18. Rotman lens for mm-wavelengths

    Science.gov (United States)

    Hall, Leonard T.; Hansen, Hedley J.; Abbott, Derek

    2002-11-01

    The 77 GHz band has been reserved for intelligent cruise control in luxury cars and some public transport services in America and the United Kingdom. The Rotman lens offers a cheap and compact means to extend the single beam systems generally used, to fully functional beam staring arrangements. Rotman lenses have been built for microwave frequencies with limited success. The flexibility of microstrip transmission lines and the advent of fast accurate simulation packages allow practical Rotman lenses to be designed at mm-wavelengths. This paper discusses the limitations of the conventional design approach and predicts the performance of a new Rotman lens designed at 77 GHz.

  19. An "ESA-affordable" Laue-lens

    DEFF Research Database (Denmark)

    Lund, Niels

    rapidly. Telescopes based on Laue diffraction of gamma-rays from crystals appear as one promising route, although the practical difficulties of realizing a large scale Laue lens are certainly not small. In this paper I have attempted to develop an optimized lens design considering the size and mass......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...

  20. Herniation of the anterior lens capsule

    Directory of Open Access Journals (Sweden)

    Pereira Nolette

    2007-01-01

    Full Text Available Herniation of the anterior lens capsule is a rare abnormality in which the capsule bulges forward in the pupillary area. This herniation can be mistaken for an anterior lenticonus where both the capsule and the cortex bulge forward. The exact pathology behind this finding is still unclear. We report the clinical, ultrasound biomicroscopy (UBM and histopathological findings of a case of herniation of the anterior lens capsule. UBM helped to differentiate this entity from anterior lenticonus. Light microscopy revealed capsular splitting suggestive of capsular delamination and collection of fluid (aqueous in the area of herniation giving it a characteristic appearance.

  1. Thin compound-eye camera.

    Science.gov (United States)

    Duparré, Jacques; Dannberg, Peter; Schreiber, Peter; Bräuer, Andreas; Tünnermann, Andreas

    2005-05-20

    An artificial compound-eye objective fabricated by micro-optics technology is adapted and attached to a CMOS sensor array. The novel optical sensor system with an optics thickness of only 0.2 mm is examined with respect to resolution and sensitivity. An optical resolution of 60 x 60 pixels is determined from captured images. The scaling behavior of artificial compound-eye imaging systems is analyzed. Cross talk between channels fabricated by different technologies is evaluated, and the influence on an extension of the field of view by addition of a (Fresnel) diverging lens is discussed. The lithographic generation of opaque walls between channels for optical isolation is experimentally demonstrated. PMID:15929282

  2. Growth of the eye lens: II. Allometric studies

    OpenAIRE

    Augusteyn, Robert C.

    2014-01-01

    Purpose The purpose of this study was to examine the ontogeny and phylogeny of lens growth in a variety of species using allometry. Methods Data on the accumulation of wet and/or dry lens weight as a function of bodyweight were obtained for 40 species and subjected to allometric analysis to examine ontogenic growth and compaction. Allometric analysis was also used to compare the maximum adult lens weights for 147 species with the maximum adult bodyweight and to compare lens volumes calculated...

  3. Floating anterior lens capsule: an unusual case of true exfoliation

    OpenAIRE

    Riffle, John

    2010-01-01

    A rare case of delamination and replication of the anterior lens capsule into prominent floating folds in the anterior chamber approximately 55 years after a penetrating injury to the eye and anterior lens capsule is reported. Classically, true exfoliation of the anterior lens capsule has been reported in individuals who have been exposed to intense heat over a prolonged period. However, more recently cases of true exfoliation of the anterior lens capsule have been reported in patients who ha...

  4. Superior Lens Coloboma with Superior Rectus Palsy and Congenital Ptosis

    OpenAIRE

    Jethani, Jitendra; Vishal R. Sharma; Marwah, Kenshuk

    2009-01-01

    A lens coloboma is characterized by the lens tissue's notching at the equator. It is usually inferior-nasal else it is called an atypical coloboma. We report a young male who presented with a superior lens coloboma, an elevation deficit and moderate ptosis, left eye. As superior rectus and levator muscles are derived from the neural crest cell we propose, genetically, there may be an association between the lens coloboma and the superior rectus/levator muscle underaction via an anomalous home...

  5. Achromatic Fresnel Lens with Improved Efficiency for PV Systems

    OpenAIRE

    Mario González Montes; Juan Carlos Martínez-Antón; Daniel Vázquez Moliní; Antonio Álvarez Fernandez-Balbuena; Bernabeu, E.

    2014-01-01

    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 hybr...

  6. 21 CFR 886.1425 - Lens measuring instrument.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1425 Lens measuring instrument. (a) Identification. A lens measuring instrument is an AC-powered device intended to measure the power of lenses... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Lens measuring instrument. 886.1425 Section...

  7. 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... lens. (a) Identification. A rigid gas permeable contact lens is a device intended to be worn directly against the cornea of the eye to correct vision conditions. The device is made of various materials,...

  8. 21 CFR 886.4300 - Intraocular lens guide.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4300 Intraocular lens guide. (a) Identification. An intraocular lens guide is a device intended to be inserted into the eye during surgery to direct... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraocular lens guide. 886.4300 Section...

  9. 21 CFR 886.1405 - Ophthalmic trial lens set.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens set. 886.1405 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1405 Ophthalmic trial lens set. (a) Identification. An ophthalmic trial lens set is a device that is a set of lenses of various dioptric...

  10. Once-punctured tori and knots in lens spaces

    OpenAIRE

    Baker, Kenneth L.

    2006-01-01

    We determine the non-null homologous knots in lens spaces whose exteriors contain properly embedded once-punctured tori. All such knots arise as surgeries on the Whitehead link and are grid number 1 in their lens spaces. As a corollary, we classify once-punctured torus bundles that admit a lens space filling.

  11. 21 CFR 886.1420 - Ophthalmic lens gauge.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic lens gauge. 886.1420 Section 886.1420...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1420 Ophthalmic lens gauge. (a) Identification. An ophthalmic lens gauge is a calibrated device intended to manually measure the curvature of...

  12. 21 CFR 886.1410 - Ophthalmic trial lens clip.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens clip. 886.1410 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1410 Ophthalmic trial lens clip. (a) Identification. An ophthalmic trial lens clip is a device intended to hold prisms, spheres, cylinders,...

  13. Hospitality as lens for migration studies

    DEFF Research Database (Denmark)

    Greve, Anni

    their duties (welfare ‘parasites’) but even betray the host. Next, an enquiry of the concept of hospitality as possible lens for migration studies; it implies a twofold analyses with two levels, a macro level, to focus our attention to the modalities of hospitality given by the juridical status of the...

  14. The special applications of Tevatron electron lens

    International Nuclear Information System (INIS)

    Besides the Tevatron Electron Lens (TEL) runs as a R and D project for Tevatron Beam-Beam Compensation, it is used daily as a Beam Abort Gap Cleaner for collider operations. It can also be served as beam exciter for beam dynamics measurements and slow proton or antiproton bunch remover. This report describes all these applications and observations

  15. Disruptive advancement in precision lens mounting

    Science.gov (United States)

    Lamontagne, Frédéric; Desnoyers, Nichola; Doucet, Michel; Côté, Patrice; Gauvin, Jonny; Anctil, Geneviève

    2015-09-01

    Threaded rings are used to fix lenses in a large portion of opto-mechanical assemblies. This is the case for the low cost drop-in approach in which the lenses are dropped into cavities cut into a barrel and clamped with threaded rings. The walls of a cavity are generally used to constrain the lateral and axial position of the lens within the cavity. In general, the drop-in approach is low cost but imposes fundamental limitations especially on the optical performances. On the other hand, active alignment methods provide a high level of centering accuracy but increase the cost of the optical assembly. This paper first presents a review of the most common lens mounting techniques used to secure and center lenses in optical systems. Advantages and disadvantages of each mounting technique are discussed in terms of precision and cost. Then, the different contributors which affect the centering of a lens when using the drop-in approach, such as the threaded ring, friction, and manufacturing errors, are detailed. Finally, a patent pending lens mounting technique developed at INO that alleviates the drawbacks of the drop-in and the active alignment approaches is introduced. This innovative auto-centering method requires a very low assembly time, does not need tight manufacturing tolerances and offers a very high level of centering accuracy, usually less than 5 μm. Centering test results performed on real optical assemblies are also presented.

  16. Changes in "thermal lens" measure diffusivity

    Science.gov (United States)

    Gupta, A.; Hong, S. D.; Moacanin, J.

    1980-01-01

    In an extension of "thermal lens" effect to new applications and better resolution, two laser beams combine to rapidly measure thermal diffusivity and other molecular dynamic properties. New double-beam technique handles very small samples unlike classical techniques for measuring diffusivity. It can be used for measurements on samples undergoing stress, making it applicable to data collection for structural engineering.

  17. Contact Lens-Related Eye Infections

    Science.gov (United States)

    ... may lead to the need for a cornea transplant . Learn more about keratitis: Bacterial keratitis Fungal keratitis Herpes keratitis Symptoms of contact lens-related infections may include blurry vision, unusual redness of the eye, pain in the eye, tearing or discharge from ...

  18. Aberrations of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    Czech Academy of Sciences Publication Activity Database

    Konvalina, Ivo; Müllerová, Ilona; Hovorka, Miloš

    Berlin : Springer, 2008 - (Luysberg, M.; Tillmann, K.; Weirich, T.), s. 569-570 ISBN 978-3-540-85154-7. [EMC 2008 - European Microscopy Congress /14./. Aachen (DE), 01.09.2008-05.09.2008] R&D Projects: GA MŠk OE08012; GA AV ČR IAA100650803 Institutional research plan: CEZ:AV0Z20650511 Keywords : cathode lens * aberrations * focus ing lens Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  19. Comparison of Different Presbyopia Treatments: Refractive Lens Exchange with Multifocal Intraocular Lens Implantation Versus LASIK Monovision

    OpenAIRE

    Barišić, Ante; Gabrić, Nikica; Dekaris, Iva; Romac, Ivana; Bohač, Maja; Jurić, Branka

    2010-01-01

    There are several methods for presbyopia treatment. Refractive lens exchange (RLE) followed by multifocal intraocular lens (MFIOL) implantation enables high rate of spectacle independance but have some visual disturbances. Laser in Situ Keratomileusis (LASIK) monovision gives patient ability to have good distant vision with dominant eye and good near vision with nondominant eye. In this prospective randomized study we wanted to compare clinical outcomes in patients who underwent either of the...

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

    OpenAIRE

    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 × 10^4 D. We studied three different aperture diameters with Fresnel numbers of the order of unity. A large focal shift was prominent at the lower Fresnel number. The measured diffraction patterns correspond to those calculated with the Kirchhoff diffraction theory for an aberration-free lens with low Fresnel numbers.

  1. A novel scanning lens instrument for evaluating Fresnel lens performance: equipment development and initial results

    OpenAIRE

    Herrero Martin, Rebeca; Miller, David C.; Kurtz, Sarah R.; Anton Hernandez, Ignacio; Sala Pano, Gabriel

    2013-01-01

    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....

  2. Changes in Monkey Crystalline Lens Spherical Aberration During Simulated Accommodation in a Lens Stretcher

    Science.gov (United States)

    Maceo Heilman, Bianca; Manns, Fabrice; de Castro, Alberto; Durkee, Heather; Arrieta, Esdras; Marcos, Susana; Parel, Jean-Marie

    2015-01-01

    Purpose. The purpose of this study was to quantify accommodation-induced changes in the spherical aberration of cynomolgus monkey lenses. Methods. Twenty-four lenses from 20 cynomolgus monkeys (Macaca fascicularis; 4.4–16.0 years of age; postmortem time 13.5 ± 13.0 hours) were mounted in a lens stretcher. Lens spherical aberration was measured in the unstretched (accommodated) and stretched (relaxed) states with a laser ray tracing system that delivered 51 equally spaced parallel rays along 1 meridian of the lens over the central 6-mm optical zone. A camera mounted below the lens was used to measure the ray height at multiple positions along the optical axis. For each entrance ray, the change in ray height with axial position was fitted with a third-order polynomial. The effective paraxial focal length and Zernike spherical aberration coefficients corresponding to a 6-mm pupil diameter were extracted from the fitted values. Results. The unstretched lens power decreased with age from 59.3 ± 4.0 diopters (D) for young lenses to 45.7 ± 3.1 D for older lenses. The unstretched lens shifted toward less negative spherical aberration with age, from −6.3 ± 0.7 μm for young lenses to −5.0 ± 0.5 μm for older lenses. The power and spherical aberration of lenses in the stretched state were independent of age, with values of 33.5 ± 3.4 D and −2.6 ± 0.5 μm, respectively. Conclusions. Spherical aberration is negative in cynomolgus monkey lenses and becomes more negative with accommodation. These results are in good agreement with the predicted values using computational ray tracing in a lens model with a reconstructed gradient refractive index. The spherical aberration of the unstretched lens becomes less negative with age. PMID:25670492

  3. 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...

  4. The influence of lens material and lens wear on the removal and viability of staphylococcus epidermidis

    OpenAIRE

    Santos, Lívia; Rodrigues, Diana Alexandra Ferreira; Lira, Madalena; Oliveira, M. Elisabete; Oliveira, Rosário; Yebra-Pimentel Vilar, Eva; Azeredo, Joana

    2008-01-01

    Purpose: The aim of this study was to evaluate the influence of lens material and lens wear on the removal capability of Staphylococcus epidermidis. Assessment of viability of remaining adhered bacteria was another goal of this work. Four silicone hydrogel materials (galyfilcon A, balafilcon A, lotrafilcon A, lotrafilcon B) and one conventional hydrogel material (etafilcon A) were assayed. Methods: Detachment studies on S. epidermidis were carried out in a parallel plate flow chamber...

  5. Zoom lens design for tilted objects

    Science.gov (United States)

    Malone, Robert M.; Frayer, Daniel K.; Kaufman, Morris I.; Leffler, Heather R.; McGillivray, Kevin D.; Meidinger, Alfred; Phillips, David H.

    2015-09-01

    When a zoom lens views a tilted finite conjugate object, its image plane is both tilted and distorted depending on magnification. Our camera image plane moves with six degrees of freedom; only one moving doublet lens is required to change magnification. Two lens design models were analyzed. The first required the optical and mechanical axes to be collinear, resulting in a tilted stop. The second allowed the optical axis to be tilted from the lens mechanical axis with an untilted stop moving along the mechanical axis. Both designs produced useful zoom lenses with excellent resolution for a distorted image. For both lens designs, the stop is anchored to the moving doublet and its diameter is unchanged throughout magnification changes. This unusual outcome allows the light level at each camera pixel to remain constant, independent of magnification. As-built tolerance analysis is used to compare both optical models. The design application is for proton radiography. At the end of an accelerator, protons exit an aluminum vacuum window producing a shadowgraph image onto an LYSO (lutetium yttrium orthosilicate) scintillator. The 5″ square scintillator emission reflects off a pellicle and is collected by the zoom lenses located 24″ away. Four zoom lenses will view the same pellicle at different alpha and beta angles. Blue emission from the scintillator is viewed at an alpha angle of -14° or -23° and beta angles of ±9° or ±25°. The pellicle directs the light backwards to a zone where adequate shielding of the cameras can be achieved against radiation scattered from the aluminum window.

  6. Preventive role of lens antioxidant defense mechanism against riboflavin-mediated sunlight damaging of lens crystallins.

    Science.gov (United States)

    Anbaraki, Afrooz; Khoshaman, Kazem; Ghasemi, Younes; Yousefi, Reza

    2016-10-01

    The main components of sunlight reaching the eye lens are UVA and visible light exerting their photo-damaging effects indirectly by the aid of endogenous photosensitizer molecules such as riboflavin (RF). In this study, lens proteins solutions were incubated with RF and exposed to the sunlight. Then, gel mobility shift analysis and different spectroscopic assessments were applied to examine the structural damaging effects of solar radiation on these proteins. Exposure of lens proteins to direct sunlight, in the presence of RF, leads to marked structural crosslinking, oligomerization and proteolytic instability. These structural damages were also accompanied with reduction in the emission fluorescence of Trp and Tyr and appearance of a new absorption peak between 300 and 400nm which can be related to formation of new chromophores. Also, photo-oxidation of lens crystallins increases their oligomeric size distribution as examined by dynamic light scattering analysis. The above mentioned structural insults, as potential sources of sunlight-induced senile cataract and blindness, were significantly attenuated in the presence of ascorbic acid and glutathione which are two important components of lens antioxidant defense system. Therefore, the powerful antioxidant defense mechanism of eye lens is an important barrier against molecular photo-damaging effects of solar radiations during the life span. PMID:27316765

  7. 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.

  8. Docking studies of Vitamin C, Vitamin E, Damnacanthal and Scopoletin with human lens gamma D-crystalline.

    Science.gov (United States)

    Rentala, Satyanarayana; Konada, Sudhakar; Chintala, Ramakrishna; Mangamoori, Lakshmi Narasu; Upadhyayula, Suryanarayana Murthy; Dhurjeti, Sarva Mangala

    2013-01-01

    Vitamin C, Vitamin E, scopoletin and damnacanthal are the major constituents of Noni (Morinda citrifolia). These compounds are known to have good medicinal properties and they are known to act as antioxidants. Loss of vision in elderly is due to opaqueness of the lens proteins such as gamma-D-crystallin during oxidative stress conditions. Therefore, it is of importance to find the potential interaction of Vitamin C, Vitamin E, Scopoletin and Damnacanthal with the lens protein gamma-D-crystallin. Hence, their physical binding to gamma-D crystallin (PDB ID: 2G98) was evaluated using molecular and structural docking procedures. Results show the potential binding of all the above anti-oxidants to gamma-D-crystalline with equal affinity. Thus, the role of cumulative anti-oxidant effect in Noni fruit juice through their potential yet predicted interaction with the lens protein gamma-D-crystallin is implied for cataract treatment. PMID:23976828

  9. 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.

  10. Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling

    Science.gov (United States)

    Chhabra, Mahendra

    The human cornea requires oxygen to sustain metabolic processes critical for its normal functioning. Any restriction to corneal oxygen supply from the external environment (e.g., by wearing a low oxygen-permeability contact lens) can lead to hypoxia, which may cause corneal edema (swelling), limbal hyperemia, neovascularization, and corneal acidosis. The need for adequate oxygen to the cornea is a major driving force for research and development of hypertransmissible soft contact lenses (SCLs). Currently, there is no standard technique for measuring oxygen permeability (Dk) of hypertransmissible silicone-hydrogel SCLs. In this work, an electrochemistry-based polarographic apparatus was designed, built, and operated to measure oxygen permeability in hypertransmissible SCLs. Unlike conventional methods where a range of lens thickness is needed for determining oxygen permeabilities of SCLs, this apparatus requires only a single lens thickness. The single-lens permeameter provides a reliable, efficient, and economic tool for measuring oxygen permeabilities of commercial hypertransmissible SCLs. The single-lens permeameter measures not only the product Dk, but, following modification, it measures separately diffusivity, D, and solubility, k, of oxygen in hypertransmissible SCLs. These properties are critical for designing better lens materials that ensure sufficient oxygen supply to the cornea. Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment, Thus, estimation of the in-vivo corneal oxygen consumption rate is essential for gauging adequate oxygen supply to the cornea. Therefore, we have developed an unsteady-state reactive-diffusion model for the cornea-contact-lens system to determine in-vivo human corneal oxygen-consumption rate. Finally, a metabolic model was developed to determine the relation between contact-lens oxygen transmissibility (Dk/L) and corneal oxygen deficiency. A

  11. Dispersion tuning with a varifocal diffractive-refractive hybrid lens.

    Science.gov (United States)

    Harm, Walter; Roider, Clemens; Jesacher, Alexander; Bernet, Stefan; Ritsch-Marte, Monika

    2014-03-10

    We present a hybrid diffractive-refractive optical lens doublet consisting of a varifocal Moiré Fresnel lens and a polymer lens of tunable refractive power. The wide range of focal tunability of each lens and the opposite dispersive characteristics of the diffractive and the refractive element are exploited to obtain an optical system where both the Abbe number and the refractive power can be changed separately. We investigate the performance of the proposed hybrid lens at zero overall refractive power by tuning the Abbe number of a complementary standard lens while maintaining a constant overall focal length for the central wavelength. As an application example, the hybrid lens is used to tune to an optimal operating regime for quantitative phase microscopy based on a two-color transport of intensity (TIE) approach which utilizes chromatic aberrations rather than intensity recordings at several planes to reconstruct the optical path length of a phase object. PMID:24663866

  12. 高陡度非球面磨削亚表面损伤深度规律%Subsurface damage rule of deep aspheric surface by grinding

    Institute of Scientific and Technical Information of China (English)

    朱登超; 戴一帆; 关朝亮; 王贵林

    2015-01-01

    Deep aspheric optical element can obviously improve the aerodynamic performance of the optical system,thus enhancing and optimizing the comprehensive performance of optical system.The grinding method can be used for primary machining of such elements.However, subsurface damage will be inevitably introduced by this method,and grinding parameters will be changing in real time in the processing of deep aspheric surface,so the depths of subsurface damage of the workpiece are inconsistent.In view of this situation,subsurface damage prediction model was established.Combined with the characteristics of semi-sphere wheels grinding,a theoretical calculation was made to predict distributive regularity of the aspheric grinding subsurface damage depths aspheric characteristics.On the basis of the above work,a simulation experiment on hot-pressing polycrystalline magnesium fluoride plane was carried out.Subsurface damage depths under different conditions of grinding parameters were acquired by the method of magnetorheological finishing spot.Results show that the depth range is between 12.79μm and 20.96μm,which increases from inside to outside along the radius of the workpiece and the results are coincide with previous forecast model.%具有高陡度非球面特性的光学元件可以明显改善光学系统的空气动力学性能,从而提升和优化系统综合性能。磨削加工方法可以作为此类元件的前期加工工序,而磨削难免会造成零件的亚表面损伤,且在这种高陡度非球面磨削加工中磨削参数是实时变化的,造成整个工件亚表面损伤深度不一致。针对这种情况,建立亚表面损伤预测模型,并结合半球形砂轮磨削的特点,通过理论计算预测非球面磨削亚表面损伤深度分布规律。在此基础上,以热压多晶氟化镁平面为对象进行模拟参数实验,通过磁流变抛斑点法得到各组参数下亚表面损伤深度情况,结

  13. 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.

  14. 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”.

  15. 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.

  16. 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.

  17. Free volume in contact lens polymers

    Science.gov (United States)

    Singh, Jag J.; Eftekhari, Abe; Upchurch, Billy T.; Burns, Karen S.

    1990-01-01

    We have measured the free volume and gas permeability in several contact lens specimens as part of a Space Commercialization Program. Free volume was measured using positron lifetime spectroscopy, while permeability for O2, N2, and CO2 gases was measured using mass spectrometry and polarography. It has been noted that permeability for all gases increases with the mean free volume cell size in the test samples. As might be expected, the specimens with the highest free volume fraction also exhibit the lowest Rockwell Hardness Number. An interesting corollary of this study is the finding that the presence of fluorine atoms in the lens chemical structure inhibits filling up of their free volume cells. This is expected to allow the lenses to breathe freely while in actual use.

  18. Stretched Lens Array Photovoltaic Concentrator Technology Developed

    Science.gov (United States)

    Piszczor, Michael F., Jr.; O'Neill, Mark J.

    2004-01-01

    Solar arrays have been and continue to be the mainstay in providing power to nearly all commercial and government spacecraft. Light from the Sun is directly converted into electrical energy using solar cells. One way to reduce the cost of future space power systems is by minimizing the size and number of expensive solar cells by focusing the sunlight onto smaller cells using concentrator optics. The stretched lens array (SLA) is a unique concept that uses arched Fresnel lens concentrators to focus sunlight onto a line of high-efficiency solar cells located directly beneath. The SLA concept is based on the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) design that was used on NASA's New Millennium Deep Space 1 mission. The highly successful asteroid/comet rendezvous mission (1998 to 2001) demonstrated the performance and long-term durability of the SCARLET/SLA solar array design and set the foundation for further improvements to optimize its performance.

  19. Aerogel detector with a Fresnel lens focalization

    International Nuclear Information System (INIS)

    The use of threshold Cherenkov detectors for the identification of high momentum particles in high energy physics experiments is connected with the efficiency of detection of light in the aerogel. As one goes lower in the refractive index, less photons are emitted, and more attention should be paid to the improvements of the detection efficiency. The light integration box method relies on photomultipliers of large size and requires even two of them. We have studied the possibility to use a thin focalizing element (Fresnel lens) between the aerogel and the photomultiplier to focalize the light onto a smaller diameter photomultiplier. The results show that for good aerogel and low indices of refraction (<1.01) the scheme with the aerogel and the Fresnel lens may be superior and less costly than the conventional set-up.

  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. Singlet vector models on lens spaces

    International Nuclear Information System (INIS)

    We present exact computations of partition functions of singlet vector models (infinite level Chern-Simons-matter theories) on lens spaces L(p,1). We identify light topological configurations and their spectra, and we comment on the relevance of our results in studying both the UV completions of Vasiliev’s higher-spin theories and the dS/CFT correspondence in the large N limit

  2. The Frontier Fields Lens Modeling Comparison Project

    OpenAIRE

    Meneghetti, M.; Natarajan, P.; Coe, D.; Contini, E.; De Lucia, G.; Giocoli, C.; Acebron, A.; S. Borgani(INFN - Trieste, c/o Dipartimento di Astronomia, Univ. di Trieste, Italy); Bradac, M.; Diego, J. M.; Hoag, A.; Ishigaki, M.; Johnson, T. L.; Jullo, E; Kawamata, R

    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 wi...

  3. Magnetic Resonance Imaging with a Dielectric Lens

    OpenAIRE

    Vazquez, F.; Marrufo, O.; MARTIN,R; Rodriguez, A. O.

    2009-01-01

    Recently, metamaterials have been introduced to improve the signal-to-noise ratio (SNR) of magnetic resonance images with very promising results. However, the use polymers in the generation of high quality images in magnetic resonance imaging has not been fully been investigated. These investigations explored the use of a dielectric periodical array as a lens to improve the image SNR generated with single surface coils. Commercial polycarbonate glazing sheets were used together with a circula...

  4. Ulcerative keratitis associated with contact lens wear

    OpenAIRE

    Bharathi M; Ramakrishnan R; Meenakshi R; Kumar C; Padmavathy S.; Mittal S

    2007-01-01

    To review the microbiological profile of ulcerative keratitis associated with contact lens (CL)-wear, 35 patients with culture-proven CL-associated microbial keratitis were studied between September 1999 and September 2002. Corneal scrapes and CL-care products were collected and were subjected to microbiological evaluation. Gram-negative bacilli alone were recovered from the corneal scrapes of all 35 (100%) patients, all 70 (100%) CL storage case wells and also from CL-care solu...

  5. Microstructure of Lentil Seeds (Lens Culinaris)

    OpenAIRE

    Hughes, Joe S.; Swanson, Barry G.

    1986-01-01

    Scanning electron microscopy (SEM) was used to investigate the microstructure of five cultivars of lentil seeds (Lens culinaris). Lentil cot yledons contain sphericai starch granules surrounded by protein bodies similar to starch granules and protein bodies observed in cotyledons of other food legumes. Examination of the lentil seed coat in cross - section revealed outer palisade and inner parenchyma layers characteris tic of legumes. The subepidermal layer, however, is comprised of hourglass...

  6. Sustained drug released from contact lens

    OpenAIRE

    Ferreira, J. A.; De Oliveira, P.; Silva, P.M. da; Carreira, A; Gil, H; Murta, J. N.

    2009-01-01

    This paper focuses on ophthalmic drug release from a loaded copolymer: the drug is dispersed in the polymeric matrix and entrapped in particles. The copolymer is based in 2-hydroxyethyl methacrylate co-methacrylic acid and silicone is used to prepare the loaded particles. A mathematical model to simulate the drug release is proposed and a qualitative analysis is performed. Experimental results are compared with simulation results. Contact lens made from the presented copolymer ...

  7. Nanoindentation of soft contact lens materials

    OpenAIRE

    Selby, Alastair Phillip

    2012-01-01

    The launch of silicone hydrogel contact lenses has led to a rise in the incidence of mechanically-related clinical complications, which is thought to be due to the increased stiffness of these materials compared to conventional hydrogel lens materials. The mechanical characteristics of hydrogel contact lenses have traditionally been investigated using tensile testing which investigated the bulk material characteristics. This thesis presents a study intended to establish a repeatable method fo...

  8. 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.

  9. 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.

  10. 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.

  11. Thin wetting film lens-less imaging

    International Nuclear Information System (INIS)

    Lens-less imaging has recently attracted a lot of attention as a compact, easy-to-use method to image or detect biological objects like cells, but failed at detecting micron size objects like bacteria that often do not scatter enough light. In order to detect single bacterium, we have developed a method based on a thin wetting film that produces a micro-lens effect. Compared with previously reported results, a large improvement in signal to noise ratio is obtained due to the presence of a micro-lens on top of each bacterium. In these conditions, standard CMOS sensors are able to detect single bacterium, e.g. E. coli, Bacillus subtilis and Bacillus thuringiensis, with a large signal to noise ratio. This paper presents our sensor optimization to enhance the SNR; improve the detection of sub-micron objects; and increase the imaging FOV, from 4.3 mm2 to 12 mm2 to 24 mm2, which allows the detection of bacteria contained in 0.5 μl to 4 μl to 10 μl, respectively. (authors)

  12. Radiation dose to the lens and cataract formation

    International Nuclear Information System (INIS)

    The purpose of this work was to determine the radiation tolerance of the lens of the eye and the incidence of radiation-induced lens changes in patients treated by fractionated supervoltage radiation therapy for orbital tumors. Forty patients treated for orbital lymphoma and pseudotumor with tumor doses of 20--40 Gy were studied. The lens was partly shielded using lead cylinders in most cases. The dose to the germinative zone of the lens was estimated by measurements in a tissue equivalent phantom using both film densitometry and thermoluminescent dosimetry. Opthalmological examination was performed at 6 monthly intervals after treatment. The lead shield was found to reduce the dose to the germinative zone of the lens to between 36--50% of the tumor dose for Cobalt beam therapy, and to between 11--18% for 5 MeV x-rays. Consequently, the lens doses were in the range 4.5--30 Gy in 10--20 fractions. Lens opacities first appeared from between 3 and 9 years after irradiation. Impairment of visual acuity ensued in 74% of the patients who developed lens opacities. The incidence of lens changes was strongly dose-related. None was seen after doses of 5 Gy or lower, whereas doses of 16.5 Gy or higher were all followed by lens opacities which impaired visual acuity. The largest number of patients received a maximum lens dose of 15 Gy; in this group the actuarial incidence of lens opacities at 8 years was 57% with visual impairment in 38%. The adult lens can tolerate a total dose of 5 Gy during a fractionated course of supervoltage radiation therapy without showing any changes. Doses of 16.5 Gy or higher will almost invariably lead to visual impairment. The dose which causes a 50% probability of visual impairment is approximately 15 Gy. 10 refs., 4 figs., 1 tab

  13. Compound lensing: Einstein zig-zags and high-multiplicity lensed images

    Science.gov (United States)

    Collett, Thomas E.; Bacon, David J.

    2016-02-01

    Compound strong gravitational lensing is a rare phenomenon, but a handful of such lensed systems are likely to be discovered in forthcoming surveys. In this work, we use a double singular isothermal sphere lens model to analytically understand how the properties of the system impact image multiplicity for the final source. We find that up to six images of a background source can form, but only if the second lens is multiply imaged by the first and the Einstein radius of the second lens is comparable to, but does not exceed that of the first. We then build a model of compound lensing masses in the Universe, using singular isothermal ellipsoid (SIE) lenses, and assess how the optical depth for multiple imaging by a galaxy-galaxy compound lens varies with source redshift. For a source redshift of 4, we find optical depths of 6 × 10-6 for multiple imaging and 5 × 10-8 for multiplicity of 6 or greater. We find that extreme magnifications are possible, with magnifications of 100 or more for 6 × 10-9 of z = 10 sources with 0.1 kpc radii. We show some of the image configurations that can be generated by compound lenses, and demonstrate that they are qualitatively different to those generated by single-plane lenses; dedicated compound lens finders will be necessary if these systems are to be discovered in forthcoming surveys.

  14. 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.

  15. Treatment of ophidism-induced bilateral canine cataract by extracapsular lens extraction and intraocular lens implantation.

    Science.gov (United States)

    Kibar, M; Evereklioğlu, C; Doğan, Z

    2014-01-01

    The aim of this study was to report a new cause of cataract, namely snake bite induced cataract in a dog. A 3-year-old male mongrel dog was referred to our clinic for the assessment of cataract in both eyes. The dog was bitten by a snake nearly 4 months ago. A 40 dioptre acrylic lens with 13 mm haptics was implanted into the lens capsule. In the left eye, posterior synechia was detected in the temporal part of the iris, but decentration of the intraocular lens was not observed. To the best of our knowledge, this is the first report of bilateral cataract caused by ophidism and treated by surgical intervention in a dog. PMID:27175143

  16. FEM simulation of the human lens compared to ex vivo porcine lens cutting pattern: a possible treatment of presbyopia

    Science.gov (United States)

    Ripken, T.; Breitenfeld, P.; Fromm, M.; Oberheide, U.; Gerten, G.; Lubatschowski, H.

    2006-02-01

    The most probable reason for presbyopia is an age related loss of elasticity of the lens. It progresses typically during the whole life and at the age of about 45 it leads to a considerable loss of the ability to accommodate within the next decade. However, both, the ciliary muscle and the lens capsule stay active and elastic, respectively. With respect to this, one concept is to regain the deformability of the lens without changing the capsule or zonular apparatus. Since the investigations of Ripken et al. proofed that the flexibility of the presbyopic lens tissue can be increased through the creation of fs-laser induced microcuts inside the lens, this is one possible approach to treat presbyopia. On this account a finite-element-method model with ANSYS of the human lens during accommodation will be presented. The analysis premises all lens materials to be linear elastic and allow large displacements. A first analysis of this method for the treatment of presbyopia is accomplished. Therefore the mechanical analysis of untreated and treated lens are compared. In addition ex-vivo elasticity measurements of untreated and treated lenses will be presented. As a result an improvement of the flexibility of the lens tissue is found and as its consequence a change of the lens radii of curvature is established. After suitable processing of the output data the change in optical power between untreated and treated lenses are calculated. The finite element simulation shows similar behaviour compared to the treated porcine lenses.

  17. Effect of selenite on 86Rb uptake by rat lens

    International Nuclear Information System (INIS)

    The effect was observed in vitro of selenite on the uptake of 86Rb by the lens in two weeks old and adult rats. Also measured was the uptake of 86Rb by the lens in vitro in 30-days old rats with cataracts induced by the administration of selenite at day 14 after birth and in control animals of the same age. Selenite in a concentration of 0.4 mM and more caused an insignificant decrease in 86Rb uptake by the lens in adult rats while in the lens of young rats the uptake decreased significantly already at concentrations lower by two orders. Lenses with cataracts took up significantly less 86Rb than transparent lenses; body weight, the weight of the fresh lens and its dry mass decreased while the water content in the lens was higher as compared with control groups. (author). 2 tabs., 26 refs

  18. Multipoint photonic doppler velocimetry using optical lens elements

    Science.gov (United States)

    Frogget, Brent Copely; Romero, Vincent Todd

    2014-04-29

    A probe including a fisheye lens is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface and then reflected back from the surface, is Doppler shifted by the moving surface, collected into fisheye lens, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to an index-matching lens and eventually to a fisheye lens. The fiber array flat polished and coupled to the index-matching lens using index-matching gel. Numerous fibers in a fiber array project numerous rays through the fisheye lens which in turn project many measurement points at numerous different locations to establish surface coverage over a hemispherical shape with very little crosstalk.

  19. A passively tunable acoustic metamaterial lens for selective ultrasonic excitation

    International Nuclear Information System (INIS)

    In this paper, we present an approach to ultrasonic beam-forming and beam-steering in structures based on the concept of embedded acoustic metamaterial lenses. The lens design exploits the principle of acoustic drop-channel that enables the dynamic coupling of multiple ultrasonic waveguides at selected frequencies. In contrast with currently available technology, the embedded lens allows exploiting the host structure as a key component of the transducer system therefore enabling directional excitation by means of a single ultrasonic transducer. The design and the performance of the lens are numerically investigated by using Plane Wave Expansion and Finite Difference Time Domain techniques applied to bulk structures. Then, the design is experimentally validated on a thin aluminum plate waveguide where the lens is implemented by through-holes. The dynamic response of the embedded lens is estimated by reconstructing, via Laser Vibrometry, the velocity field induced by a single source located at the center of the lens

  20. Studies on the diffraction image of a thermal lens.

    Science.gov (United States)

    Jürgensen, F; Schröer, W

    1995-01-01

    We calculated the intensity distribution behind a thermal lens by using a numerical quadrature of the Fresnel diffraction integral and compared it to several given approximate models for laser light detection in the center behind a thermal lens, which includes a new approximate solution of the diffraction integral with applicability to strong thermal lenses. Consideration of the aberrant nature of the thermal lens is crucial even if the thermal lens is weak. A simple approximate formula for the position of the most intense interference ring stating a linear dependence of the thermal lens strength is given. The transverse profile of a weak thermal lens is discussed. It is shown that spherical aberration modifies the central intensity even if a Gaussian profile is observed. PMID:20963083

  1. 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.

  2. Magnesium compounds

    Science.gov (United States)

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  3. Characterization and localization of side population cells in the lens

    OpenAIRE

    Oka, Mikako; Toyoda, Chizuko; Kaneko, Yuka; Nakazawa, Yosuke; Aizu-Yokota, Eriko; Takehana, Makoto

    2010-01-01

    Purpose Side population (SP) cells were isolated and the possibility whether lens epithelial cells contain stem cells was investigated. Methods Mouse lens epithelial cells were stained by Hoechst 33342 and then sorted by fluorescence-activated cell sorting (FACS). The expression of stem cell markers in sorted SP cells and the main population of epithelial cells were analyzed by quantitative real-time PCR. Localization of SP cells in the mouse lens was studied by fluorescence microscopy. Resul...

  4. Functions of the intermediate filament cytoskeleton in the eye lens

    OpenAIRE

    Song, Shuhua; Landsbury, Andrew; Dahm, Ralf; Liu, Yizhi; Zhang, Qingjiong; Quinlan, Roy A.

    2009-01-01

    Intermediate filaments (IFs) are a key component of the cytoskeleton in virtually all vertebrate cells, including those of the lens of the eye. IFs help integrate individual cells into their respective tissues. This Review focuses on the lens-specific IF proteins beaded filament structural proteins 1 and 2 (BFSP1 and BFSP2) and their role in lens physiology and disease. Evidence generated in studies in both mice and humans suggests a critical role for these proteins and their filamentous poly...

  5. Ring lens for focusing ion beams to uniform densities

    International Nuclear Information System (INIS)

    An electrostatic lens was designed and built to focus a beam of positive ions into uniform density on a target. The lens has two concentric field regions with a grid separating the inner zero field from the outer radial field. For proper operation the incident ions must emanate with axial symmetry and Gaussian or similar divergence from a small source. An appendix is included on the symmetrization of elliptical beams by a quadrupole singlet lens. (U.S.)

  6. Microbial Keratitis: Could Contact Lens Material Affect Disease Pathogenesis?

    OpenAIRE

    Evans, David J.; Fleiszig, Suzanne M. J.

    2013-01-01

    Microbial keratitis is a sight-threatening complication associated with contact lenses. The introduction of silicone hydrogel lens materials with increased oxygen transmission to the ocular surface has not significantly altered the incidence of microbial keratitis. These data suggest that alternate, or additional, predisposing factors involving lens wear must be addressed to reduce or eliminate these infections. The contact lens can provide a surface for microbial growth in situ, and can also...

  7. 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...

  8. Reduction of pantethine in rabbit ocular lens homogenate.

    Science.gov (United States)

    Fisher, D H; Szulc, M E

    1997-02-01

    In several animal models, preliminary studies have indicated that pantethine may inhibit cataract formation. Therefore, preclinical trials need to be conducted to study the pharmacology of pantethine in the ocular lens and to establish its efficacy. Since pantethine, which is a disulfide, can undergo a variety of chemical modifications such as reduction and formation of mixed disulfides, a detailed study was first conducted to determine the stability of pantethine in rabbit lens homogenate. A knowledge of the stability of pantethine in lens homogenate was necessary to establish if pantethine could be metabolized in the time it takes to harvest and homogenize a lens. The results of this study will be used to establish a protocol for harvesting and homogenizing lens samples. Pantethine (100 microM) is completely reduced to pantetheine in rabbit lens homogenate in about 16 min. About 1.5% of the pantethine added to lens homogenate forms a mixed disulfide with lens proteins, and the remainder is found in the supernatant. The supernatant pantethine concentration decreases exponentially as a function of time, and the terminal half-life for this process is 3.3 min. The free supernatant pantetheine concentration increases in pseudo first order manner as a function of time with a rate constant of 4.3 min. Pantethinase activity is not significant, because the free supernatant pantetheine concentration did not decrease. The exact mechanism of pantethine reduction in rabbit lens homogenate remains to be determined. PMID:9127277

  9. Propagation of Lissajous singularities through an astigmatic lens

    International Nuclear Information System (INIS)

    The analytical expression for the propagation of Lissajous singularities through an astigmatic lens is derived and used to study the dynamic evolution of Lissajous singularities after passing through the astigmatic lens and the dependence of Lissajous singularities on the control parameters where the effect of astigmatism of the lens is stressed. It is shown that motion, pair creation and annihilation, handedness reversal and change in the degree of polarization of Lissajous singularities may take place. In particular, a single Lissajous singularity may appear and vanish due to the presence of the astigmatic lens

  10. Lens Extrusion from Laminin Alpha 1 Mutant Zebrafish

    OpenAIRE

    Mallika Pathania; Semina, Elena V; Duncan, Melinda K.

    2014-01-01

    We report analysis of the ocular lens phenotype of the recessive, larval lethal zebrafish mutant, lama1 a69/a69 . Previous work revealed that this mutant has a shortened body axis and eye defects including a defective hyaloid vasculature, focal corneal dysplasia, and loss of the crystalline lens. While these studies highlight the importance of laminin α1 in lens development, a detailed analysis of the lens defects seen in these mutants was not reported. In the present study, we analyze the le...

  11. 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.

  12. 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.

  13. 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.

  14. Seeing lens imaging as a superposition of multiple views

    CERN Document Server

    Grusche, Sascha

    2015-01-01

    In the conventional approach to lens imaging, rays are used to map object points to image points. However, many students have a need to think of the image as a whole. To answer this need, lens imaging is reinterpreted as a superposition of sharp images from different viewpoints. These so-called elemental images are uncovered by covering the lens with a pinhole array. Rays are introduced to connect elemental images. Lens ray diagrams are constructed based on bundles of elemental images. The conventional construction method is included as a special case. The proposed approach proceeds from concrete images to abstract rays.

  15. Seeing lens imaging as a superposition of multiple views

    Science.gov (United States)

    Grusche, Sascha

    2016-01-01

    In the conventional approach to lens imaging, rays are used to map object points to image points. However, many students want to think of the image as a whole. To answer this need, Kepler’s ray drawing is reinterpreted in terms of shifted camera obscura images. These images are uncovered by covering the lens with pinholes. Thus, lens imaging is seen as a superposition of sharp images from different viewpoints, so-called elemental images. This superposition is simulated with projectors, and with transparencies. Lens ray diagrams are constructed based on elemental images; the conventional construction method is included as a special case.

  16. Assessing the elasticity change of cataract lens with OCE

    Science.gov (United States)

    Wu, Chen; Liu, Chih-Hao; Raghunathan, Raksha; Singh, Manmohan; Li, Jiasong; Han, Zhaolong; Larin, Kirill V.

    2016-03-01

    Cataract is one of the most common degenerative diseases that causes blindness. Careful quantification of lens biomechanical properties can greatly assist in early detection of the disease as well as personalization of treatment procedures. In this study, we utilize a phase-sensitive optical coherence elastography (OCE) system to assess the effects of the cold cataract on the biomechanical properties of porcine crystalline lens in vitro. Relaxation rates of air puff induced elastic waves were measured on the same crystalline lens with and without cold cataract. Results demonstrate that the relaxation rate and, thus, associated elasticity of the porcine lens, increased due to the presence of cold cataract.

  17. Abnormal lens morphogenesis and ectopic lens formation in the absence of beta-catenin function

    Czech Academy of Sciences Publication Activity Database

    Krešlová, Jana; Machoň, Ondřej; Růžičková, Jana; Láchová, Jitka; Wawrousek, E.F.; Kemler, R.; Krauss, S.; Piatigorsky, J.; Kozmik, Zbyněk

    2007-01-01

    Roč. 45, č. 4 (2007), s. 157-168. ISSN 1526-954X R&D Projects: GA ČR GA204/04/1358 Institutional research plan: CEZ:AV0Z50520514 Keywords : Wnt * beta-catenin * gene * lens Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.516, year: 2007

  18. 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...

  19. Magnetic Resonance Imaging with a Dielectric Lens

    CERN Document Server

    Vazquez, F; Martin, R; Rodriguez, A O

    2009-01-01

    Recently, metamaterials have been introduced to improve the signal-to-noise ratio (SNR) of magnetic resonance images with very promising results. However, the use polymers in the generation of high quality images in magnetic resonance imaging has not been fully been investigated. These investigations explored the use of a dielectric periodical array as a lens to improve the image SNR generated with single surface coils. Commercial polycarbonate glazing sheets were used together with a circular coil to generate phantom images at 3 Tesla on a clinical MR imager.

  20. Liquid crystal adaptive lens with circular electrodes

    Science.gov (United States)

    Sun, Yi

    The liquid crystal adaptive lens (LCAL) developed in this research is an electro-optical device using a set of electrodes to grade the refractive index across its aperture. Adjusting the applied voltages permits continuous control of focal length. The first effort at developing an LCAL using circular electrodes to provide a simpler architecture than previous devices using linear electrodes is presented in this dissertation. A theoretical study for an LCAL with circular electrodes is performed. The liquid crystal behavior and the applied voltage profile required for different focal lengths is discussed. Numerical simulation of the refractive index change and the Point Spread Function is developed to study the aberrations and predict performance with circular electrode geometry. A Fresnel lens phase profile is applied to yield a lens with a useful F-number, and a previously unexplored aberration is identified and characterized. An LCAL prototype was designed with a set of high-density electrodes in the conductive ladder meshing configuration, which results in a small number of externally controlled electrodes. A new electronic controller was designed and built with a fast response and accurate output to apply the voltage set to the LCAL. An electro-optical feedback control system based on LabVIEW software was developed to optimize control output voltages using signals from a CID camera. A prototype LCAL was designed with a 7.86 mm diameter aperture and a focal length adjustable from 0.2 m to infinity. It was fabricated on a glass substrate with two layers of transparent electrodes, insulating layers, and vias to connect the two conducting layers. The special fabrication challenges involved are discussed. Focusing experiments were performed by auto-dithering using the electro-optical feedback control system. The point spread function measurement results are presented, demonstrating that the focal spot size reaches the diffraction limit, but astigmatism created by the

  1. 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.

  2. Hyperbolic metamaterial lens with hydrodynamic nonlocal response

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...

  3. 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...

  4. Combining crystallographic information and an aspherical-atom data bank in the evaluation of the electrostatic interaction energy in an enzyme–substrate complex: influenza neuraminidase inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Dominiak, Paulina M., E-mail: pdomin@chem.uw.edu.pl [Department of Chemistry, State University of New York at Buffalo, NY 14260 (United States); Department of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warszawa (Poland); Volkov, Anatoliy; Dominiak, Adam P. [Department of Chemistry, State University of New York at Buffalo, NY 14260 (United States); Jarzembska, Katarzyna N. [Department of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warszawa (Poland); Coppens, Philip, E-mail: pdomin@chem.uw.edu.pl [Department of Chemistry, State University of New York at Buffalo, NY 14260 (United States)

    2009-05-01

    The electrostatic component of the enzyme/inhibitor interaction of a wide range influenza neuraminidases and inhibitors has been analyzed using transferable aspherical-atom densities from a recently compiled databank. Results are subdivided into the contributions of individual active-site residues and different functional groups of the inhibitors, and the effect of the Arg292→Lys mutation is considered. Although electrostatic interactions contribute only a part of the interaction energies between macromolecules, unlike dispersion forces they are highly directional and therefore dominate the nature of molecular packing in crystals and in biological complexes and contribute significantly to differences in inhibition strength among related enzyme inhibitors. In the reported study, a wide range of complexes of influenza neuraminidases with inhibitor molecules (sialic acid derivatives and others) have been analyzed using charge densities from a transferable aspherical-atom data bank. The strongest interactions of the residues are with the acidic group at the C2 position of the inhibitor (∼−300 kJ mol{sup −1} for —COO{sup −} in non-aromatic inhibitors, ∼−120–210 kJ mol{sup −1} for —COO{sup −} in aromatic inhibitors and ∼−450 kJ mol{sup −1} for —PO{sub 3}{sup 2−}) and with the amino and guanidine groups at C4 (∼−250 kJ mol{sup −1}). Other groups contribute less than ∼100 kJ mol{sup −1}. Residues Glu119, Asp151, Glu227, Glu276 and Arg371 show the largest variation in electrostatic energies of interaction with different groups of inhibitors, which points to their important role in the inhibitor recognition. The Arg292→Lys mutation reduces the electrostatic interactions of the enzyme with the acidic group at C2 for all inhibitors that have been studied (SIA, DAN, 4AM, ZMR, G20, G28, G39 and BCZ), but enhances the interactions with the glycerol group at C6 for inhibitors that contain it. This is in agreement with the lower level

  5. 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...

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

    Science.gov (United States)

    Abdel-Hadi, Yasser A.; Ghitas, A.; Abulwfa, A.; Sabry, M.

    2015-12-01

    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.

  7. 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

  8. Aldose reductase inhibitory compounds from Xanthium strumarium.

    Science.gov (United States)

    Yoon, Ha Na; Lee, Min Young; Kim, Jin-Kyu; Suh, Hong-Won; Lim, Soon Sung

    2013-09-01

    As part of our ongoing search for natural sources of therapeutic and preventive agents for diabetic complications, we evaluated the inhibitory effects of components of the fruit of Xanthium strumarium (X. strumarium) on aldose reductase (AR) and galactitol formation in rat lenses with high levels of glucose. To identify the bioactive components of X. strumarium, 7 caffeoylquinic acids and 3 phenolic compounds were isolated and their chemical structures were elucidated on the basis of spectroscopic evidence and comparison with published data. The abilities of 10 X. strumarium-derived components to counteract diabetic complications were investigated by means of inhibitory assays with rat lens AR (rAR) and recombinant human AR (rhAR). From the 10 isolated compounds, methyl-3,5-di-O-caffeoylquinate showed the most potent inhibition, with IC₅₀ values of 0.30 and 0.67 μM for rAR and rhAR, respectively. In the kinetic analyses using Lineweaver-Burk plots of 1/velocity and 1/substrate, methyl-3,5-di-O-caffeoylquinate showed competitive inhibition of rhAR. Furthermore, methyl-3,5-di-O-caffeoylquinate inhibited galactitol formation in the rat lens and in erythrocytes incubated with a high concentration of glucose, indicating that this compound may be effective in preventing diabetic complications. PMID:23604720

  9. 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-thermoelectric materials both by adjusting the carrier concentration and by reducing the thermal conductivity. Here, we report the effects of doping on the thermoelectric properties of 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.

  10. 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.

  11. 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. PMID:27304276

  12. 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.

  13. Metamaterial radiofrequency lens for magnetic resonance imaging

    CERN Document Server

    Freire, Manuel J; Jelinek, Lukas; Gil, Eduardo; Moya, Francisco

    2009-01-01

    The purpose of this work is to test the ability of a new class of passive electromagnetic device to increase the penetration depth of phased arrays of surface coils for magnetic resonance (MR) imaging systems. This new device is based on the emerging technology of metamaterials and behaves like a lens for the radiofrequency magnetic fields. The presented device was tested in several 1.5-T MR systems from different companies in combination with different phased arrays. One of the authors was enrolled as volunteer for the experiments. In these experiments his knees were imaged by using a dual phased array. The device was placed between the knees to check that the penetration depth of the coils was improved by this passive device. In all the experiments the presented device was successfully tested and it was checked that the knees of the volunteer can be imaged at deeper distances and that the signal-to-noise-ratio (SNR) in the obtained MR images was improved by the presence of the lens. The presented device has...

  14. Non-linear cluster lens reconstruction

    CERN Document Server

    Kaiser, N

    1994-01-01

    We develop a method for general non-linear cluster lens reconstruction using the observable distortion of background galaxies. The distortion measures the combination \\gamma/(1-\\kappa) of shear \\gamma and surface density \\kappa. From this we obtain an expression for the gradient of \\log (1 - \\kappa) in terms of directly measurable quantities. This allows one to reconstruct 1 - \\kappa up to an arbitrary constant multiplier. Recent work has emphasised an ambiguity in the relation between the distortion and \\gamma/(1-\\kappa). Here we show that the functional relation depends only on the parity of the images, so if one has data extending to large radii, and if the critical lines can be visually identified (as lines along which the distortion diverges), this ambiguity is resolved. Moreover, we show that for a generic 2-dimensional lens it is possible to locally determine the parity from the distortion. The arbitrary multiplier, which may in fact take a different value in each region bounded by the contour \\kappa =...

  15. 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

  16. Primary defects in the lens underlie complex anterior segment abnormalities of the Pax6 heterozygous eye

    OpenAIRE

    Collinson, J. Martin; Quinn, Jane C.; Buchanan, Malcolm A.; Kaufman, Matthew H.; Wedden, Sarah E.; West, John D.; Hill, Robert E.

    2001-01-01

    We describe lens defects in heterozygous small eye mice, and autonomous deficiencies of Pax6+/− cells in the developing lens of Pax6+/+ ↔ Pax6+/− chimeras. Two separate defects of the lens were identified by analyzing the distribution of heterozygous cells in chimeras: Pax6+/− cells are less readily incorporated into the lens placode than wild type, and those that are incorporated into the lens are not maintained efficiently in the proliferating lens epithelium...

  17. Calculation of Light Distribution on a Focal Plane of a Contact Lens Carved Fresnel Zone Plate

    OpenAIRE

    NAMEDA, Naoyoshi; ナメダ, ナオヨシ; 行田, 尚義

    1993-01-01

    A bifocal lens function has been difficult to achieve in a contact lens. As a solution to the problem, a diffraction bifocal contact lens was developed by Freeman in 1982. This report shows the results of the calculation of light distribution condensed by a diffraction type contact lens. This lens gives near vision focal length by first order subsidiary light, and far vision focal length by Oth order subsidiary light of the refraction power of the lens. The method followed in this inves...

  18. The "Youth Lens": Analyzing Adolescence/ts in Literary Texts

    Science.gov (United States)

    Petrone, Robert; Sarigianides, Sophia Tatiana; Lewis, Mark A.

    2014-01-01

    Drawing from interdisciplinary scholarship that re-conceptualizes adolescence as a cultural construct, this article introduces a "Youth Lens." A "Youth Lens" comprises an approach to textual analysis that examines how ideas about adolescence and youth get formed, circulated, critiqued, and revised. Focused specifically on its…

  19. 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.

  20. Electromagnetic modes of Maxwell fish-eye lens

    CERN Document Server

    Rosu, H C

    1996-01-01

    We provide an analysis of the radial structure of TE and TM modes of the Maxwell fisheye lens, by means of Maxwell equations as applied to the fisheye case. Choosing a lens of size R = 1 cm, we plot some of the modes in the infrared range.

  1. Bioinspired solid-liquid mixed tunable lens with multilayered structure

    Science.gov (United States)

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

    2015-06-01

    A solid-liquid mixed tunable lens with multilayered structure is proposed. The designed lens utilizes a solid-state elastic polymer, optical liquid, and glass as the optical medium, and adjusts the focus by changing the surface curvature of the elastic polymer. The integrated structure of the tunable lens is presented, as well as detailed descriptions of the lens materials, fabrication, and assembling process. Images captured through the tunable lens under different displacement loads are presented, and the relationship among the displacement load, curvature radius, and effective focal length is analyzed. Additionally, the optical property of the tunable lens is simulated using the ZEMAX software. A change in focal length from 14.8 mm to 30 mm is demonstrated within the tiny 0.12 mm variation of the displacement load. Numerical analyses show that the lens distortion is less than 2%, and the modulation transfer function reaches 67 line pairs per mm. The solid-liquid mixed tunable lens shows the potential for developing a compact, low-aberration, and stable optical system.

  2. 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

  3. 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 in...

  4. The linear Fresnel lens solar concentrator: Transverse tracking error effects

    Science.gov (United States)

    Cosby, R. M.

    1977-01-01

    The solar concentration performance of a line focusing, flat base Fresnel lens in the presence of small transverse tracking errors was analyzed. Solar transmittance of the lens and focal plane imaging characteristics were evaluated. Transmission losses by reflectance and material absorption were also studied.

  5. Unilateral phacoemulsification and intraocular lens implantation in a dachshund

    OpenAIRE

    Kopala, Robyn L.

    2008-01-01

    A 1.5-year-old, spayed, female dachshund was presented with a cataract and lens-induced uveitis in the left eye. The cataract progressed from immature to hypermature in 4 months. Phacoemulsification and intraocular lens implantation was performed and the dog remains visual in the left eye 1 year post-surgery.

  6. Near UV radiation effect on the lens and retina

    International Nuclear Information System (INIS)

    The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

  7. 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.

  8. 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

  9. 21 CFR 886.1415 - Ophthalmic trial lens frame.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens frame. 886.1415 Section 886.1415 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1415 Ophthalmic trial lens frame....

  10. Compound odontoma

    Directory of Open Access Journals (Sweden)

    José Marcelo Vargas Pinto

    2008-01-01

    Full Text Available Odontomas are the most common types of odontogenic tumors, as they are considered more as a developmental anomaly (hamartoma than as a true neoplasia. The aim of the present study is to describe a clinical case of compound odontoma, analyzing its most commonsigns, its region of location, the decade of life and patient’s gender, disorders that may occur as well as the treatment proposed. In order to attain this objective, the method was description of the present clinical case and bibliographic revision, arriving at the result that the treatment for this type of lesion invariably is surgical removal (enucleation and curettage and the prognosis is excellent. The surgical result was followed up in the post-operative period by radiographic exam, and it was possible to conclude that there was complete cicatrization and tissue repair.

  11. Development of a new process for manufacturing precision gobs out of new developed low Tg optical glasses for precise pressing of aspherical lenses; Technical Digest

    Science.gov (United States)

    Jaschek, Rainer; Klein, Christopher; Schenk, Christian; Schneider, Klaus; Freund, Jochen; Simone, Ritter

    2005-05-01

    Aspherical lenses or refractive elements out of optical glass can be produced either by grinding and polishing of glass or by precise molding of glass preforms. The first process is applied for lenses with larger geometries and smaller production quantities. On the other hand, precise molding is used for volume production of lenses within a diameter range between 1 mm and around 30 mm. The addressed products can be found in the consumer markets (digital imaging, digital projection and digital storage). Different preform types can be used for precise molding: polished spherical near shape preforms, polished balls, polished discs and precision gobs. The latter are made directly from the glass melt. This paper describes a newly developed process, which results in fire-polished gobs with very low surface roughness and excellent volume accuracy. Since precision gobs are mostly made for precise molding, they must meet specific process requirements apart form their optical values, such as allowing low molding temperatures and shorter process cycles times. Therefore, this paper also describes the latest results in the development of low Tg glasses, which are designed for the volume production of precision molded optical components. Beside the important parameters like nd, nd as well as Tg, other properties like chemical durability, devitrification resistance, thermal expansion and conductivity coefficients are important for optimizing the precise molding process. The characteristics of three new low Tg glasses in the FK-, PK- as well as SK-region are presented. These glasses are environmentally friendly, since they are free of lead and arsenic.

  12. 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 ...

  13. 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.

  14. Multifunctional metasurface lens for imaging and Fourier transform

    Science.gov (United States)

    Wen, Dandan; Yue, Fuyong; Ardron, Marcus; Chen, Xianzhong

    2016-06-01

    A metasurface can manipulate light in a desirable manner by imparting local and space-variant abrupt phase change. Benefiting from such an unprecedented capability, the conventional concept of what constitutes an optical lens continues to evolve. Ultrathin optical metasurface lenses have been demonstrated based on various nanoantennas such as V-shape structures, nanorods and nanoslits. A single device that can integrate two different types of lenses and polarities is desirable for system integration and device miniaturization. We experimentally demonstrate such an ultrathin metasurface lens that can function either as a spherical lens or a cylindrical lens, depending on the helicity of the incident light. Helicity-controllable focal line and focal point in the real focal plane, as well as imaging and 1D/2D Fourier transforms, are observed on the same lens. Our work provides a unique tool for polarization imaging, image processing and particle trapping.

  15. 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...

  16. Status of eye lens radiation dose monitoring in European hospitals.

    Science.gov (United States)

    Carinou, Eleftheria; Ginjaume, Merce; O'Connor, Una; Kopec, Renata; Sans Merce, Marta

    2014-12-01

    A questionnaire was developed by the members of WG12 of EURADOS in order to establish an overview of the current status of eye lens radiation dose monitoring in hospitals. The questionnaire was sent to medical physicists and radiation protection officers in hospitals across Europe. Specific topics were addressed in the questionnaire such as: knowledge of the proposed eye lens dose limit; monitoring and dosimetry issues; training and radiation protection measures. The results of the survey highlighted that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens protection is crucial. Personnel should be properly trained in how to use protective equipment in order to keep eye lens doses as low as reasonably achievable. Finally, the results also highlighted the need to improve the design of eye dosemeters in order to ensure satisfactory use by workers. PMID:25222935

  17. Lens aberration measurement and analysis using a novel pattern

    Science.gov (United States)

    Nam, Byung-Ho; Cho, Byeong-Ho; Park, Jong O.; Kim, Dong-Seok; Baek, SungJin; Jeong, JongHo; Nam, ByungSub; Hwang, Young J.; Song, Young Jin

    2001-09-01

    Lens aberration of the exposure tool causes pattern deformation and position shift. As design rule shrinks, the ratio of printed feature size to applied wavelength for optical lithography is driven inexorably toward resolution limit. In this study, we devised an efficient method to evaluate lens aberration using multi-ring pattern on an attenuated phase-shift mask. Adoption of multi-ring pattern can cut down measurement time and improve measurement repeatability. These patterns are uniformly distributed through entire field in 7 by 7 manner. Lens aberration was evaluated by multi-ring pattern array under conventional or off-axis illumination with KrF stepper of NA 0.65. Multi-ring critical dimension (CD) data was discussed together with the issue of lens aberration such as coma, astigmatism, field curvature, etc. We can apply this new measurement technique to select better lens system efficiently. multi-ring, field size, pattern deformation

  18. Cellulose based soft gel like actuator for reconfigurable lens array

    Science.gov (United States)

    Sadasivuni, Kishor Kumar; Yadav, Mithilesh; Gao, Xiaoyuan; Mun, Seongcheol; Kim, Jaehwan

    2014-04-01

    Reconfigurable lens is biomimetic as it mimics human eye and is a transparent actuating material that can change its curvature in the presence of external stimuli. Focus tunable, adaptive lenses provide several advantages over traditional lens assemblies in terms of compactness, cost, efficiency and flexibility. To further improve the simplicity and compact nature of adaptive lenses, we present lens system which makes use of an inline, transparent electro active polymer actuator. This paper reports the preliminary development we have achieved in reconfigurable lens systems made with cellulose nanocrystals (CNC) using the principle of Kerr effect. Preparation of the hydrophobic CNC solution as well as the optical properties of the lens has been discussed. This soft gel actuator was analyzed by measuring the electric birefringence in the pulse field of constant and sinusoidal voltage based on the use of modulation of elliptic light polarization.

  19. Gabor lens focusing of a negative ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Palkovic, J.A.; Mills, F.E.; Schmidt, C.; Young, D.E.

    1989-05-01

    Gabor or plasma lenses have previously been used to focus intense beams of positive ions at energies from 10 keV to 5 MeV. It is the large electrostatic field of the non-neutral plasma in the Gabor lens which is responsible for the focusing. Focusing an ion beam with a given sign of charge in a Gabor lens requires a non-neutral plasma with the opposite sign of charge as the beam. A Gabor lens constructed at Fermilab has been used to focus a 30 keV proton beam with good optical quality. We discuss studies of the action of a Gabor lens on a beam of negative ions. A Gabor lens has been considered for matching an H/sup /minus// beam into an RFQ in the redesign of the low energy section of the Fermilab linac. 9 refs., 3 figs., 1 tab.

  20. Gabor lens focusing of a negative ion beam

    International Nuclear Information System (INIS)

    Gabor or plasma lenses have previously been used to focus intense beams of positive ions at energies from 10 keV to 5 MeV. It is the large electrostatic field of the non-neutral plasma in the Gabor lens which is responsible for the focusing. Focusing an ion beam with a given sign of charge in a Gabor lens requires a non-neutral plasma with the opposite sign of charge as the beam. A Gabor lens constructed at Fermilab has been used to focus a 30 keV proton beam with good optical quality. We discuss studies of the action of a Gabor lens on a beam of negative ions. A Gabor lens has been considered for matching an H/sup /minus// beam into an RFQ in the redesign of the low energy section of the Fermilab linac. 9 refs., 3 figs., 1 tab

  1. Status of eye lens radiation dose monitoring in European hospitals

    International Nuclear Information System (INIS)

    A questionnaire was developed by the members of WG12 of EURADOS in order to establish an overview of the current status of eye lens radiation dose monitoring in hospitals. The questionnaire was sent to medical physicists and radiation protection officers in hospitals across Europe. Specific topics were addressed in the questionnaire such as: knowledge of the proposed eye lens dose limit; monitoring and dosimetry issues; training and radiation protection measures. The results of the survey highlighted that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens protection is crucial. Personnel should be properly trained in how to use protective equipment in order to keep eye lens doses as low as reasonably achievable. Finally, the results also highlighted the need to improve the design of eye dosemeters in order to ensure satisfactory use by workers. (paper)

  2. Do gravitational lens galaxies have an excess of luminous substructure?

    CERN Document Server

    Nierenberg, A M; Treu, T

    2013-01-01

    Strong gravitational lensing can be used to directly measure the mass function of their satellites, thus testing one of the fundamental predictions of cold dark matter cosmological models. Given the importance of this test it is essential to ensure that galaxies acting as strong lenses have dark and luminous satellites which are representative of the overall galaxy population. We address this issue by measuring the number and spatial distribution of luminous satellites in ACS imaging around lens galaxies from the Sloan Lens Advanced Camera for Surveys (SLACS) lenses, and comparing them with the satellite population in ACS imaging of non lens galaxies selected from COSMOS, which has similar depth and resolution to the ACS images of SLACS lenses. In order to compare the samples of lens and non lens galaxies, which have intrinsically different stellar mass distributions, we measure, for the first time, the number of satellites per host as a continuous function of host stellar mass for both populations. We find t...

  3. Focusing properties of a square electrostatic rainbow lens doublet

    Directory of Open Access Journals (Sweden)

    Telečki Igor N.

    2015-01-01

    Full Text Available This is a study on the properties of a square electrostatic rainbow lens doublet. The said optical element consists of two square electrostatic rainbow lenses with the second lens axially rotated for 45 degrees with respect to the first one. The propagation of a proton beam with a kinetic energy of 10 keV through the doublet is in the focus of our analysis. The potential of the electrodes of both lenses is 2 kV. The electrostatic potential and the electric field components of the lens doublet are calculated using a 3-D computer code based on the method of moments. Spatial and angular distributions of protons propagating through the lens doublet, as well as the parameters defining beam quality, are investigated. As in the case of the single square electrostatic rainbow lens, the evolution of these distributions is determined by the evolution of corresponding rainbow lines, generated by the use of the theory of crystal rainbows. Our study shows that a beam core in the shape of a cusped square is formed by the spatial rainbow line that appears first. This rainbow line occurs during proton propagation through the first lens. The beam core retains the cusped square shape during the propagation through the second lens. The electrostatic field of the second lens causes the appearance of an additional spatial rainbow line, which encompasses the beam core and defines the outer border of the beam. This rainbow line constitutes the main difference between the cases of the lens doublet and a single lens. [Projekat Ministarstva nauke Republike Srbije, br. III45006

  4. 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.

  5. 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

  6. The sloan lens acs survey. II. Stellar populations and internal structure of early-type lens galaxies

    NARCIS (Netherlands)

    Treu, Tommaso; Koopmans, Léon V.; Bolton, Adam S.; Burles, Scott; Moustakas, Leonidas A.

    2006-01-01

    We use HST images to derive effective radii and effective surface brightnesses of 15 early-type (E+S0) lens galaxies identified by the SLACS Survey. Our measurements are combined with stellar velocity dispersions from the SDSS database to investigate for the first time the distribution of lens galax

  7. 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®.

  8. 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

  9. Evaluation of resources for contact lens practice in private contact lens clinics of Muscat, Oman

    OpenAIRE

    Rajiv Khandekar; Mohammed Al Fahdi

    2009-01-01

    Background: The integration of the contact lens (CL) practice with the VISION 2020 initiative is important. We assessed the facilities at the private CL clinics of Muscat. Accordingly, we suggested the appropriate eye care for CL wearers in Oman. Study Design: This was a descriptive study. 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 hu...

  10. 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. PMID:26168329

  11. Ulcerative keratitis associated with contact lens wear

    Directory of Open Access Journals (Sweden)

    Bharathi M

    2007-01-01

    Full Text Available To review the microbiological profile of ulcerative keratitis associated with contact lens (CL-wear, 35 patients with culture-proven CL-associated microbial keratitis were studied between September 1999 and September 2002. Corneal scrapes and CL-care products were collected and were subjected to microbiological evaluation. Gram-negative bacilli alone were recovered from the corneal scrapes of all 35 (100% patients, all 70 (100% CL storage case wells and also from CL-care solution of six (17.14% of the 35 patients. There was a significantly higher number of Pseudomonas aeruginosa (71.43% isolated from eyes with CL-related keratitis than other bacterial isolates (28.57% ( P < 0.001. Microbial contamination of CL storage cases was a great risk for gram-negative bacterial infection among soft CL-wearers.

  12. The correction of electron lens aberrations.

    Science.gov (United States)

    Hawkes, P W

    2015-09-01

    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. PMID:26025209

  13. Ulcerative keratitis associated with contact lens wear.

    Science.gov (United States)

    Bharathi, M Jayahar; Ramakrishnan, R; Meenakshi, R; Kumar, C Shiv; Padmavathy, S; Mittal, S

    2007-01-01

    To review the microbiological profile of ulcerative keratitis associated with contact lens (CL)-wear, 35 patients with culture-proven CL-associated microbial keratitis were studied between September 1999 and September 2002. Corneal scrapes and CL-care products were collected and were subjected to microbiological evaluation. Gram-negative bacilli alone were recovered from the corneal scrapes of all 35 (100%) patients, all 70 (100%) CL storage case wells and also from CL-care solution of six (17.14%) of the 35 patients. There was a significantly higher number of Pseudomonas aeruginosa (71.43%) isolated from eyes with CL-related keratitis than other bacterial isolates (28.57%) (P<0.001). Microbial contamination of CL storage cases was a great risk for gram-negative bacterial infection among soft CL-wearers. PMID:17189892

  14. Actual Stationary State for Plasma Lens

    CERN Document Server

    Zadorozhny, Vladimir F; Parsa, Zohreh

    2005-01-01

    The electrostatic plasma lens (PL) provides an attractive and unique tool for manipulating high-current heavy ion beams. The fundamental concept of the PL is based on the use of magnetically insulated electrons and equipotentialization of magnetic field lines. Rigorous application of PL is, however, limited. The reason is the estimation behaviour of electrons for complicated magnetic fields runs into severe difficults.We show that there are specific conditions that admit steady-state of a longitudinal motion, and consider a question of it stability. These results are needed to develop an optimized PL with minimal spherical aberation, in party by optimization of the magnetic field conficuration in the low-magnetic-field range.

  15. Modulating permanent sextupole triple magnet lens

    International Nuclear Information System (INIS)

    We are developing a permanent magnet sextupole lens (PMSx) that can focus pulsed neutron. It is based on the extended Halbach configuration to generate stronger magnetic field. In order to modulate the strength of magnetic field, the magnet is divided into nested rings, where the inner ring is fixed and outer ring can be rotated. Synchronizing the phase of the modulation with time-of-flight of pulsed neutron beam suppresses the chromatic aberration. This device can focus very cold neutron (VCN) with wavelength from 2.7 to 5.5 nm at a focal length of about 1m. In triple-magnet model, the operation performance has been upgraded. A torque canceling system using permanent magnet is installed to reduce the motor load. In addition, a cooling fan for magnetic pole and neutron flight path filled with helium are installed. (author)

  16. 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...

  17. UM 425 - A new gravitational lens candidate

    International Nuclear Information System (INIS)

    The discovery of a probable gravitational lens associated with the quasar UM 425 = QSO 1120+019 is reported. BVR images of the object were obtained with a CCD using a 1.5-m telescope in March, 1987. Three close companions were observed around the bright image of the quasar. Follow-up spectroscopy suggests that the brightest companion has the same emission lines as the quasar. The velocity difference between the two brightest components from the cross-correlation technique is shown to be 200 + or - 100 km/s and is consistent with zero. Subtracting a scaled spectrum of the brighter component from the brightest companion leaves a residual which is interpreted as the spectrum of a lensing galaxy at a redshift of about 0.6. 18 refs

  18. Prototype color field sequential television lens assembly

    Science.gov (United States)

    1974-01-01

    The design, development, and evaluation of a prototype modular lens assembly with a self-contained field sequential color wheel is presented. The design of a color wheel of maximum efficiency, the selection of spectral filters, and the design of a quiet, efficient wheel drive system are included. Design tradeoffs considered for each aspect of the modular assembly are discussed. Emphasis is placed on achieving a design which can be attached directly to an unmodified camera, thus permitting use of the assembly in evaluating various candidate camera and sensor designs. A technique is described which permits maintaining high optical efficiency with an unmodified camera. A motor synchronization system is developed which requires only the vertical synchronization signal as a reference frequency input. Equations and tradeoff curves are developed to permit optimizing the filter wheel aperture shapes for a variety of different design conditions.

  19. Motherhood transition through an existential lens

    DEFF Research Database (Denmark)

    Prinds, Christina Lange

    2015-01-01

    Motherhood transition is a significant life event. Research from various disciplines outlines pregnancy, birth and the initial period of motherhood as a period of life in which a woman might experience disruption and gain new perspectives in a bodily, psychological, social and existential way. This...... research about the significance of motherhood transition through the lens of existential psychology. For the second and third study, a nationwide questionnaire survey among Danish first-time FT and PT mothers was conducted. In the second study attitudes about making meaning of life existentially was...... may be even more relevant for women giving birth preterm, since research suggests that mothers of premature babies undergo an experience of loss, crisis and unpredictability. This PhD project aimed to identify whether motherhood transition actualises considerations on how to make meaning of life...

  20. Quantum Weighted Projective and Lens Spaces

    Science.gov (United States)

    D'Andrea, Francesco; Landi, Giovanni

    2015-11-01

    We generalize to quantum weighted projective spaces in any dimension previous results of us on K-theory and K-homology of quantum projective spaces `tout court'. For a class of such spaces, we explicitly construct families of Fredholm modules, both bounded and unbounded (that is, spectral triples), and prove that they are linearly independent in the K-homology of the corresponding C *-algebra. We also show that the quantum weighted projective spaces are base spaces of quantum principal circle bundles whose total spaces are quantum lens spaces. We construct finitely generated projective modules associated with the principal bundles and pair them with the Fredholm modules, thus proving their non-triviality.

  1. 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. PMID:26072893

  2. 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.

  3. Intraocular lens employed for cataract surgery

    International Nuclear Information System (INIS)

    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.

  4. 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.

  5. Focusing properties of a square electrostatic rainbow lens

    International Nuclear Information System (INIS)

    This paper is devoted to the focusing properties of a square electrostatic rainbow lens, which is a novel ion beam optical element. We consider the transmission of parallel and non-parallel proton beams of the initial kinetic energy of 10 keV through this lens. The potential of the electrodes of the lens is chosen to be 2 kV. The electrostatic potential and components of the electric field in the region of the lens are calculated using a three-dimensional finite element computer code. We investigate the spatial and angular distributions of protons propagating through the lens and in the drift space after it. It is confirmed that the evolutions of these distributions are determined by the evolutions of the corresponding rainbow lines, generated using the theory of crystal rainbows. The beam is separated into two components. One beam component, appearing as a beam core, is generated dominantly by the focused protons. Its boundary line in the transverse position plane can be very well approximated by a hypotrochoid. The other beam component is generated dominantly by the defocused protons. We present the focusing coefficient of the lens, the confining coefficients of the lens for the focused and defocused protons, the density of the beam core, the vertical or horizontal emittance of the beam core, and the brightness of the beam core.

  6. Challenges of using dielectric elastomer actuators to tune liquid lens

    Science.gov (United States)

    Keong, Gih-Keong; La, Thanh-Giang; Shiau, Li-Lynn; Tan, Adrian W. Y.

    2014-03-01

    Recently, dielectric elastomer actuators (DEAs) have been adopted to tune liquid membrane lens, just like ciliary muscles do to the lens in human eye. However, it faces some challenges, such as high stress, membrane puncture, high driving voltage requirement, and limited focus distance (not more than 707cm), that limit its practical use. The design problem gets more complex as the liquid lens shares the same elastomeric membrane as the DEA. To address these challenges, we separate DEA from the lens membrane. Instead, a liquid-immersed DEA, which is safe from terminal failure, is used as a diaphragm pump to inflate or deflate the liquid lens by hydraulic pressure. This opens up the possibility that the DEA can be thinned down and stacked up to reduce the driving voltage, independent of the lens membrane thickness. Preliminary study showed that our 8-mm-diameter tunable lens can focus objects in the range of 15cm to 50cm with a small driving voltage of 1.8kV. Further miniaturization of DEA could achieve a driving voltage less than 1kV.

  7. LASL lens design procedure: simple, fast, precise, versatile

    Energy Technology Data Exchange (ETDEWEB)

    Brixner, B.

    1978-11-01

    The Los Alamos Scientific Laboratory general-purpose lens design procedure optimizes specific lens prescriptions to obtain the smallest possible image spots and therefore near-spherical wave fronts of light converging on all images in the field of view. Optical image errors are analyzed in much the same way that they are measured on the optical bench. This lens design method is made possible by using the full capabilities of large electronic computers. First, the performance of the whole lens is sampled with many precisely traced skew rays. Next, lens performance is analyzed with spot diagrams generated by the many rays. Third, lens performance is optimized with a least squares system aimed at reducing all image errors to zero. This statistical approach to lens design uses skew rays and precisely measured ray deviations from ideal image points to achieve greater accuracy than was possible with the classical procedure, which is based on approximate expressions derived from simplified ray traces developed for pencil-and-paper calculations.

  8. 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.

  9. 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.

  10. 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.

  11. Vortexlike Power Flow at the Interfaces of Metamaterial Lens

    Directory of Open Access Journals (Sweden)

    K. Fang

    2012-08-01

    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.

  12. Can Maxwell's fish eye lens really give perfect imaging?

    OpenAIRE

    Sun, Fei; He, Sailing

    2010-01-01

    Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens [bounded with a perfectly electrical conductor (PEC) boundary]. We show that such a 2D Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in Maxwell's fish eye lens. If only zeroth order mode is excited, a good image of a sharp object may be achieved ...

  13. The gravitational lens effect and its optical equivalents

    International Nuclear Information System (INIS)

    This work presents the evolution of the use of the so called gravitational lens effect from a simple observational teste of the General Relativity theory to an instrument to measure cosmological parameters. A detailed analysis of how a gravitational ''lens'' deflects light without forming images is shown for the case of the deflector with spherical symmetry. In addition, the exact optical equivalent of a cylindrical gravitational lens, which forms true images, is proposed. Finally the problem of the formation of multiple images and the related astronomical observations is discussed. (author)

  14. Multiplexing schemes for an achromatic programmable diffractive lens

    Energy Technology Data Exchange (ETDEWEB)

    Millan, M S; Perez-Cabre, E; Oton, J [Technical University of Catalonia, Dep. Optics and Optometry, Terrassa-Barcelona, 08222 (Spain)], E-mail: millan@oo.upc.edu

    2008-11-01

    A multiplexed programmable diffractive lens, displayed on a pixelated liquid crystal device under broadband illumination, is proposed to compensate for the severe chromatic aberration that affects diffractive elements. The proposed lens is based on multiplexing a set of sublenses with a common focal length for different wavelengths. We consider different types of integration of the optical information (spatial only, temporal only and hybrid spatial-temporal) combined with a proper selection of the spectral bandwidth. The properties and limits of the achromatic programmable multiplexed lens are described. Experimental results are presented and discussed.

  15. Multiplexing schemes for an achromatic programmable diffractive lens

    International Nuclear Information System (INIS)

    A multiplexed programmable diffractive lens, displayed on a pixelated liquid crystal device under broadband illumination, is proposed to compensate for the severe chromatic aberration that affects diffractive elements. The proposed lens is based on multiplexing a set of sublenses with a common focal length for different wavelengths. We consider different types of integration of the optical information (spatial only, temporal only and hybrid spatial-temporal) combined with a proper selection of the spectral bandwidth. The properties and limits of the achromatic programmable multiplexed lens are described. Experimental results are presented and discussed.

  16. Development of a Fresnel lens concentrator for space application

    Science.gov (United States)

    Oneill, Mark J.; Piszczor, Michael F.

    1987-01-01

    The selected conceptual design of the dome lens photovoltaic concentrator for space applications uses a 3.7 cm square aperture dome lens to focus onto a 0.4 cm active diameter gallium arsenide cell. The selected configuration will provide 91.5 percent lens optical efficiency and 21.4 percent cell efficiency at 100 suns irradiance and 100 C cell temperature, for an overall cell efficiency of 19.6 percent. The selected configuration will tolerate 1 degree tracking errors with negligible loss of performance. The selected panel weight is 2.5 kg/sq.m.

  17. Lenses matching of compound eye for target positioning

    Science.gov (United States)

    Guo, Fang; Zheng, Yan Pei; Wang, Keyi

    2012-10-01

    Compound eye, as a new imaging method with multi-lens for a large field of view, could complete target positioning and detection fastly, especially at close range. Therefore it could be applicated in the fields of military and medical treatment and aviation with vast market potential and development prospect. Yet the compound eye imaging method designed use three layer construction of multiple lens array arranged in a curved surface and refractive lens and imaging sensor of CMOS. In order to simplify process structure and increase the imaging area of every sub-eye, the imaging area of every eye is coved with the whole CMOS. Therefore, for several imaging point of one target, the corresponding lens of every imaging point is unkonown, and thus to identify. So an algorithm was put forward. Firstly, according to the Regular Geometry relationship of several adjacent lenses, data organization of seven lenses with a main lens was built. Subsequently, by the data organization, when one target was caught by several unknown lenses, we search every combined type of the received lenses. And for every combined type, two lenses were selected to combine and were used to calculate one three-dimensional (3D) coordinate of the target. If the 3D coordinates are same to the some combine type of the lenses numbers, in theory, the lenses and the imaging points are matched. So according to error of the 3D coordinates is calculated by the different seven lenses numbers combines, the unknown lenses could be distinguished. The experimental results show that the presented algorithm is feasible and can complete matching task for imaging points and corresponding lenses.

  18. 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

  19. 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

  20. Design and development of a laminated Fresnel lens for point-focus PV systems. Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, R.C.

    1982-12-01

    A laminated glass-plastic lens parquet using injection molded point focus Fresnel lenses is described. The second phase of a program aimed at investigating the cost effectiveness of a glass-plastic concentrator lens assembly is reported. The first phase dealt with the development of a first generation lens design, the selection of the preferred glass coverplate and glass-to-lens adhesive and initial injection molding lens molding trials. The second phase has dealt with the development of an improved lens design, a full size parquet lamination process, and a second group of injection molding lens molding trials.

  1. 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...

  2. Observations of underdense plasma lens focusing of relativistic electron beams

    International Nuclear Information System (INIS)

    Focusing of a 15 MeV, 19 nC electron bunch by an underdense plasma lens operated just beyond the threshold of the underdense condition has been demonstrated in experiments at the Fermilab NICADD Photoinjector Laboratory (FNPL). The strong 1.9 cm focal-length plasma-lens focused both transverse directions simultaneously and reduced the minimum area of the beam spot by a factor of 23. Analysis of the beam-envelope evolution observed near the beam waist shows that the spherical aberrations of this underdense lens are lower than those of an overdense plasma lens, as predicted by theory. Correlations between the beam charge and the properties of the beam focus corroborate this conclusion

  3. Ultrastructural study of lens fiber damages after laser irradiation

    International Nuclear Information System (INIS)

    Lens fiber lesion after laser irradiation were studied in albino rats. Loss of cytoplasmic constrast, pulling apart of intercellular cell junctions and increase of intracellular vesicles were observed. (orig.)

  4. Low-Cost Homemade Liquid-Lens Refractometer.

    Science.gov (United States)

    Narayanan, V. Anantha; Narayanan, Radha

    1996-01-01

    Describes the experimental and theoretical details for constructing and calibrating an inexpensive, homemade liquid-lens refractometer. Measures refractive indices that are within the experimental errors discussed and close to the literature values. (JRH)

  5. Experimental Contact Lens to Prevent Glaucoma-Induced Blindness

    Science.gov (United States)

    ... An Experimental Contact Lens to Prevent Glaucoma-Induced Blindness By Sharon Reynolds Posted January 23, 2014 An ... group of conditions that can result in irreversible blindness. This vision loss can be reduced if glaucoma ...

  6. Dielectric Optical-Controllable Magnifying Lens by Nonlinear Negative Refraction

    Science.gov (United States)

    Cao, Jianjun; Shang, Ce; Zheng, Yuanlin; Feng, Yaming; Chen, Xianfeng; Liang, Xiaogan; Wan, Wenjie

    2015-07-01

    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 indices. Recent advancements in nanotechnology enable novel lenses, such as, superlens and hyperlens, with sub-wavelength resolution capabilities by specially designed materials’ refractive indices with meta-materials and transformation optics. However, these artificially nano- or 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 the nonlinear regime, achieving an all-optical controllable lensing effect through nonlinear wave mixing, which may have many potential applications in microscopy and imaging science.

  7. 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.

  8. Gravitational lenses and lens candidates identified from the COSMOS field

    CERN Document Server

    Jackson, Neal

    2008-01-01

    A complete manual search has been carried out of the list of 285423 objects, nearly all of them galaxies, identified in the COSMOS field that are brighter than I=25. Two certain and one highly probable new gravitational lenses are found, in addition to the lenses and candidate lens systems previously found by Faure et al. (2008). A further list of 112 candidate lens systems is presented. Few of these are likely to be true gravitational lens systems, most being star-forming rings or pairs of companion galaxies. It is possible to examine of order 10^6 objects by eye in a reasonable time, although reliable detection of lenses by such methods is likely to be possible only with high-resolution data. The loss of completeness involved in a rapid search is estimated as up to a factor of 2, depending on the morphology of the lens candidate.

  9. Hyperbolic tangential function-based progressive addition lens design.

    Science.gov (United States)

    Qiu, Gufeng; Cui, Xudong

    2015-12-10

    The diopter distribution is key to the successful design of a progressive addition lens. A hyperbolic tangential function is then introduced to describe well the desired diopter distribution on the lens. Simulation and fabrication show that the astigmia on the whole surface is very close to the addition, exhibiting superior performance than that of currently used high-order polynomials and cosine functions. Our investigations found that once the diopter distribution design is reasonable, both the direct and indirect methods of constructing a progressive addition lens can give consistent results. With this function we are able to effectively control the design of critical areas, the position, sizes of far-view and near-view zones, as well as the channel of the lens. This study would provide an efficient way to customize different progressive lenses not only for presbyopia, but also for anti-fatigue, office progressive usages, etc. PMID:26836863

  10. Plasma lens experiments at the Final Focus Test Beam

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, B. [California Univ., Los Angeles, CA (United States)]|[Lawrence Berkeley Lab., CA (United States); Chattopadhyay, S. [Lawrence Berkeley Lab., CA (United States); Chen, P. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)] [and others

    1993-04-01

    We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5 {times} 10{sup 10}, tunneling ionization of a gas target by an electron beam -- an effect which has never been observed before -- should be significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.

  11. Flat acoustic lens by acoustic grating with curled slits

    International Nuclear Information System (INIS)

    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

  12. 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.

  13. Magnifying lens for 800 MeV proton radiography

    International Nuclear Information System (INIS)

    This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution.

  14. On the operational quantity Hp(3) for eye lens dosimetry

    International Nuclear Information System (INIS)

    In the past the operational quantity Hp(3) has been defined for calibration purposes in a slab phantom. Recently, an additional phantom in the form of a cylinder was suggested for eye lens dosimetry as a cylinder much better approximates the shape of a head than a slab. Therefore, this work investigates whether the quantity Hp(3), when defined in the respective calibration phantom, adequately estimates the eye lens dose (or is at least conservative) depending on the phantom: it turns out that in most cases both calibration phantoms are similarly well suited. Finally, the definition of the eye lens dose is discussed together with possible consequences on the definition of Hp(3): the consideration of only the radiation sensitive volume of the lens causes Hp(3) not to be conservative in beta radiation fields. (paper)

  15. 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.

  16. A single-pixel wireless contact lens display

    International Nuclear Information System (INIS)

    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.

  17. Intraocular electro-optic lens with ciliary muscle controlled accommodation.

    Science.gov (United States)

    Doornaert, Dries; Glorieux, Christ; De Gersem, Herbert; Puers, Robert; Spileers, Werner; Blanckaert, Johan

    2013-01-01

    In this paper a concept is proposed of an intraocular lens implant with electro-optic accommodation of a variable-focus hybrid liquid-crystal-based lens. The dioptric strength of the lens is electronically controlled by a signal that is derived from the change of inductance of a sensing coil due to a marker implanted in the nearby contracting or decontracting ciliary muscle. Analytical, numerical and experimental results are reported on the dependency of the frequency of a Colpitts oscillator circuit on the location of a nearby conductive marker. A concept is also reported on the use as an electro-optic lens of a device based on a liquid crystal in planar alignment, which is held between a flat and a curved window coated with optically transparent and electrically conductive layers. PMID:24110406

  18. 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. PMID:27254279

  19. 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...

  20. Eye lens irradiation by CT perfusion: dosimetry and optimization

    International Nuclear Information System (INIS)

    The lens of the eye is a radiosensitive organ. In April 2011, the International Commission on Radiological Protection (ICRP) set the new threshold dose of occurrence of deterministic lens effects to 500 mGy. Patients with a ruptured intracranial aneurysm are imaged by CT scans of the brain (CT), for diagnosis and post-treatment follow-up; embolization is the standard treatment. These iterative examinations expose the lens to X-rays. This paper evaluates the lens X-ray exposure of 18 patients who underwent encephalic CT scans after a ruptured intracranial aneurysm in 2011, and proposes a method to reduce this exposure. In our study, 44% of patients received eye doses greater than 500 mGy, generated by CT examinations, especially cerebral CT perfusion, necessary to assess the risk of delayed vasospasm/ischemia. By positioning the patient in neck hyper-flexion for cerebral CT perfusion, the dose could be reduced by around 50%. (authors)