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Conference on current developments in lens design and optical engineering XvI

作者： Miller, Kevin H. Quijada, Manuel A. Leviton, Douglas B. NASA Goddard Space Flight Ctr Greenbelt MD 20771 USA Leviton Metrol Solut Inc Boulder CO 80301 USA

ISBN: (纸本)9781628417449

The Transiting Exoplanet Survey Satellite (TESS) is an explorer-class planet finder whose principal goal is to detect small planets with bright host stars in the solar neighborhood. The TESS payload consists of four identical cameras with seven lens elements, each made from various Ohara glass. The successful implementation of both the panchromatic and the thermal aspect of these lens assemblies requires accurate knowledge of the thermal and spectral dependence of the refractive index in the wavelength and temperature ranges of operation. Hence, this paper reports measurements of the refractive index for the following Ohara glasses over the wavelength range 0.42 - 1.10 mu m and temperature range 120 300 K: S-LAH55, S-LAH55v, S-LAH59, S-LAM3, S-NBM51, S-NPH2, S-PHM52, and S-TIH14. The measurements were performed using the Cryogenic High Accuracy Refraction Measuring System (CHARMS) facility at NASA Goddard Space Flight Center. Dense coverage of absolute refractive indices of these glasses over the aforementioned wavelength and temperature ranges allowed accurate determination of spectral thermo-optic coefficients (dn/dT) and spectral dispersions (dn/d lambda) as a function of temperature. A comparison of measured, temperature-dependent indices to literature values is presented for S-PHM52 and S-TIH14. A comparison to Ohara's catalog indices at room temperature is presented for all of the materials.

关键词： S-LAH55 S-LAH55v S-LAH59 S-LAM3 S-NBM51 S-NPH2 S-PHM52 S-TIH14 CHARMS cryogenic refractive index

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Modeling and design of a multichannel chromatic aberration compensated imaging system 16

Modeling and design of a multichannel chromatic aberration c...

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Conference on current developments in lens design and optical engineering XvI

作者： Belay, Gebirie Y. Ottevaere, Heidi vervaeke, Michael van Erps, Jurgen Thienpont, Hugo Vrije Univ Brussel Fac Engn Dept Appl Phys & Photon TONA Brussels Photon TeamB PHOT B-1050 Brussels Belgium

ISBN: (纸本)9781628417449

Conventional multichannel imaging systems comprise of many optical channels having similar imaging properties, namely field-of-view (FOv) and angular resolution/magnification. We demonstrated that the different optical channels can be designed such that each optical channel captures a different FOv and angular resolution compared to its neighboring channels. We designed and experimentally demonstrated a three-channel multiresolution imaging system where the first optical channel has the narrowest FOv (7 degrees) and highest angular resolution (0.0096 degrees) and the third optical channel has the widest FOv (80 degrees) and lowest angular resolution (0.0780 degrees)(1). The second optical channel has intermediate properties. The performance of the demonstrated three-channel imaging system however was affected by chromatic aberrations as it was designed for a single wavelength of 587.6 nm. The first optical channel was largely influenced by longitudinal chromatic aberration while the third channel by lateral chromatic aberration. Therefore, we have replaced the aspherical refractive lenses by hybrid lenses, which contain diffractive structures on top of their refractive surfaces, in the three-channel multiresolution imaging system to reduce its chromatic aberrations. The performance of the three channels with hybrid lenses is compared with those of the corresponding channels without hybrid lenses. The longitudinal color aberration of the first optical channel has been reduced from 1.7 mm to 0.2 mm;whereas the lateral color aberration of the third optical channel has been reduced from 250 mu m to 14 mu m. In conclusion, the hybrid lenses have reduced the chromatic aberrations of the three channels and extended the operating spectral range of the imaging system in the visible wavelength range.

关键词： Multi-resolution imaging systems angular resolution multi-channel chromatic aberrations

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Proceedings of SPIE - The International Society for optical engineering

Proceedings of SPIE - The International Society for Optical ...

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Conference on current developments in lens design and optical engineering XvI

ISBN: (纸本)9781628417449

The proceedings contain 24 papers. The topics discussed include: integration design of endoscope with different viewing angles;ultra-compact hourglass lens for integrated cameras;testing and alignment of freeform based multi-mirror telescopes;tolerancing an optical freeform surface: an optical fabricator's perspective;manufacture and analysis of a refractive surface with variable asphericity to model the human cornea;modeling and design of a multichannel chromatic aberration compensated imaging system;temperature-dependent refractive index measurements of L-BBH2 glass for the Subaru CHARIS integral field spectrograph;cryogenic refractive indices of S-LAH55, S-LAH55v, S-LAH59, S-LAM3, S-NBM51, S-NPH2, S-PHM52, and S-TIH14 glasses;temperature-dependent refractive index measurements of CaF2, Suprasil 3001, and S-FTM16 for the Euclid near-infrared spectrometer and photometer;design considerations for an unconventional infrared prism with a 90 degree ray deviation;and high-performance LED luminaire for sports hall.

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design of a Thomson scattering diagnostic system for vEST

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FUSION engineering AND design 2015年第Oct.期96-97卷 882-886页

作者： Kim, Young-Gi Lee, Jong Ha Lee, Jeongwon An, YoungHwa Dang, Jeong Jeung Jo, Jungmin Lee, HyunYeong Chung, Kyoung-Jae Hwang, Y. S. Na, Yong-Su Seoul Natl Univ Dept Nucl Engn Seoul 151744 South Korea Natl Fus Res Inst Taejon 305333 South Korea

A Thomson scattering diagnostic system is designed for versatile Experiment Spherical Torus (vEST) to measure the spatial profiles of the electron temperature. The system is carefully designed to collect a sufficient number of photoelectrons and to reduce the noise sources, since relatively low electron densities and temperatures are expected in vEST due to the limited power capacity at present. The target electron temperature and the density are 10-200 ev and 5 x 10(18) m(-3), respectively which are extrapolated from the data of triple Langmuir probes measuring the edge plasma parameters at R=0.75 m by assuming a parabolic density profile. The collecting optics is designed to have a wide-view angle and low cost by using a commercial photographic lens of low f-number and high transmittance optical fiber bundle. The bandwidths of the interference filters in the polychromator are designed for reliable measurements within the target electron temperature range. As a photo detector which is coupled with the filters, an avalanche photodiode (APD) with a low dark current and an adequate quantum efficiency near the laser wavelength is selected for the high signal-to-noise ratio. The number of photons transferred to the polychromator and the number of photoelectrons in the APD are calculated. At the commissioning phase, an oscilloscope with a high sampling rate will be adopted to check the necessity of the noise reduction by multi-shot signal accumulation. (c) 2015 Elsevier B.v. All rights reserved.

关键词： Spherical torus versatile Experiment Spherical Torus vEST Thomson scattering Electron temperature measurement

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design of a Thomson scattering diagnostic system for vEST

Design of a Thomson scattering diagnostic system for VEST

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28th Symposium on Fusion Technology (SOFT)

关键词： Spherical torus versatile Experiment Spherical Torus vEST Thomson scattering Electron temperature measurement

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Nonimaging Achromatic lens design for LED Direct-lit Backlight Applications 15

Nonimaging Achromatic Lens Design for LED Direct-lit Backlig...

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Conference on current developments in lens design and optical engineering Xv

作者： Tsai, Meng-Che Chen, Bo-Song Lee, Tsung-Xian Natl Taiwan Univ Sci & Technol Grad Inst Appl Sci & Technol 43Sec 4Keelung Rd Taipei 106 Taiwan Natl Taiwan Univ Sci & Technol Grad Inst Color & Illuminat Technol Taipei 106 Taiwan

ISBN: (纸本)9781628412192

Nowadays, light emitting diodes (LEDs) have been widely used in backlight module for display technology. Most of researches tend to improve optical performance in specific applications, such as sufficient efficiency, desired intensity distribution and high illuminance uniformity. However, most of phosphor converted white LEDs have the problem of inducing impure white light. The undesired phenomenon of yellow ring or blue ring becomes more serious through incorrect secondary optical design. In this paper, we emphasize on enhancing the spatial color and illuminance uniformity of LED direct-lit backlight using nonimaging achromatic lens design. We propose a new design method to re-distribute and uniform the ratio of blue and yellow light on the target surface. Moreover, we further apply it in direct-lit LED backlight lens design, in which the uniformity of illuminance on the out coupling surface can be as much as 83.7% and the color uniformity (Delta u'v') is improved to 0.0039. Therefore, the result of high color and illumination uniformity can be achieved simultaneously.

关键词： LED direct-lit backlight Achromatic lens design Illuminance uniformity Color uniformity

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Study of Camera Calibration Process with Ray Tracing 15

Study of Camera Calibration Process with Ray Tracing

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Conference on current developments in lens design and optical engineering Xv

作者： Poulin-Girard, A. -S. Dallaire, X. veillette, A. Thibault, S. Laurendeau, D. Univ Laval Dept Phys Genie Phys & Opt Ctr Opt Photon & Laser Quebec City PQ G1V 0A6 Canada Univ Laval Dept gen elect & gen informat Lab vision & syst numer Quebec City G1V 0A6 PQ Canada

ISBN: (纸本)9781628412192

Camera calibration is essential for any optical system used to obtain 3D measurements from images. The precision of the 3D depth estimation relies on an appropriate camera model and the accurate estimation of model parameters. These parameters are sensitive to environmental conditions and it is well established that a vision system should be calibrated in operating conditions. This is not always possible since the calibration process is often tedious and time-consuming. Unfortunately, the use of poorly estimated calibration parameters for 3D reconstruction and measurements may lead to suboptimal performance of the system and inaccurate depth estimation. This paper presents a technique using an existing camera model and optical design software to perform calibration simulations. This virtual calibration technique allows for a study of the impact of environmental conditions on the calibration parameters. Using this procedure, it is also possible to predict the statistical behavior of the calibration parameters considering the chosen fabrication processes and tolerances. It can assist vision scientists in the choice of the optical system that best meets the requested precision of the 3D reconstruction. This technique could eventually be integrated in the lens design process to create more reliable optical systems that could be calibrated and used in a range of environmental conditions with a very small variation of their calibration parameters.

关键词： Camera calibration optical design software tolerancing lens design

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Chromatic error correction of diffractive optical elements at minimum etch depths 15

Chromatic error correction of diffractive optical elements a...

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Conference on current developments in lens design and optical engineering Xv

作者： Barth, Jochen Guehne, Tobias Airbus Def & Space Landshuter Str 26 D-85716 Unterschleissheim Germany Airbus Def & Space D-81663 Munich Germany

ISBN: (纸本)9781628412192

The integration of diffractive optical elements (DOE) into an optical design opens up new possibilities for applications in sensing and illumination. If the resulting optics is used in a larger spectral range we must correct not only the chromatic error of the conventional, refractive, part of the design but also of the DOE. We present a simple but effective strategy to select substrates which allow the minimum etch depths for the DOEs. The selection depends on both the refractive index and the dispersion.

关键词： Diffractive optics Aberration compensation

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Afocal viewport optics for underwater imaging 15

Afocal viewport optics for underwater imaging

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Conference on current developments in lens design and optical engineering Xv

作者： Slater, Dan 1352 Dorothea Rd La Habra Hts CA 90631 USA

ISBN: (纸本)9781628412192

A conventional camera can be adapted for underwater use by enclosing it in a sealed waterproof pressure housing with a viewport. The viewport, as an optical interface between water and air needs to consider both the camera and water optical characteristics while also providing a high pressure water seal. Limited hydrospace visibility drives a need for wide angle viewports. Practical optical interfaces between seawater and air vary from simple flat plate windows to complex water contact lenses. This paper first provides a brief overview of the physical and optical properties of the ocean environment along with suitable optical materials. This is followed by a discussion of the characteristics of various afocal underwater viewport types including flat windows, domes and the Ivanoff corrector lens, a derivative of a Galilean wide angle camera adapter. Several new and interesting optical designs derived from the Ivanoff corrector lens are presented including a pair of very compact afocal viewport lenses that are compatible with both in water and in air environments and an afocal underwater hyper-hemispherical fisheye lens.

关键词： Afocal lens design underwater photography water contact lens Ivanoff corrector lens dome port hyperhemispherical fisheye lens

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optical design of Low Glare Luminaire Applied for Tunnel Light 15

Optical Design of Low Glare Luminaire Applied for Tunnel Lig...

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Conference on current developments in lens design and optical engineering Xv

作者： Tsai, M. S. Lee, X. H. Lo, Y. C. Sun, C. C. Natl Cent Univ Dept Opt & Photon Chungli 320 Taiwan

ISBN: (纸本)9781628412192

In this study, a low glare and high-efficient tunnel lighting design which consists of a cluster light-emitting diode and a free-form lens is presented. Most of the energy emitted from the proposed luminaire is transmitted onto the surface of the road in front of drivers, and the probability that the energy is emitted directly into drivers' eyes is low. Compared with traditional fluorescent lamps, the proposed luminaire, of which the optical utilization factor, optical efficiency, and uniformity are, respectively, 44%, 92.5%, and 0.72, performs favorably in traffic safety, energy saving, and glare reduction.

关键词： Light-emitting diodes Illumination design Nonimaging optics optical design and fabrication

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