Proceedings Volume 8128

Current Developments in Lens Design and Optical Engineering XII; and Advances in Thin Film Coatings VII

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Proceedings Volume 8128

Current Developments in Lens Design and Optical Engineering XII; and Advances in Thin Film Coatings VII

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Volume Details

Date Published: 7 September 2011
Contents: 7 Sessions, 19 Papers, 0 Presentations
Conference: SPIE Optical Engineering + Applications 2011
Volume Number: 8128

Table of Contents

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Table of Contents

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  • Front Matter: Volume 8128
  • Lens Design and Optical Engineering I
  • Advances in SSL
  • Lens Design and Optical Engineering II
  • Thin Film Optical Coating
  • Design Methods and Techniques
  • Poster Session
Front Matter: Volume 8128
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Front Matter: Volume 8128
This PDF file contains the front matter associated with SPIE Proceedings Volume 8128, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.
Lens Design and Optical Engineering I
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Cryogenic lens design case study: Gemini Planet Imager spectrograph
Making a lens design working at cryogenic temperature is a real challenge. Both optical and mechanical designer must work together to prevent problems during operation. The Gemini Planet Imager (GPI), currently under construction will be a facility instrument for the 8-m Gemini South telescope. The science instrument is a cryogenic integral field spectrograph based on a lenslet array. The integral field nature of the instrument allows for a full mapping of the focal plane at coarse spectral resolution. With such a data cube, artifacts within the PSF such as residual speckles can be suppressed. Additionally, the initial detection of any candidate planet will include spectral information that can be used to distinguish it from a background object: candidates can be followed up with detailed spectroscopic observations. The optics between the lenslet array and the detector are essentially a standard spectrograph with a collimating set of lenses, a dispersive prism and a camera set of lenses in a folded assembly. This paper describes the process from the first preliminary design to the final cryogenic system for both optical and mechanical design to achieve cryogenic working solution. We also discussed the assembly procedure (room temperature vs cryogenic compensation), the test support equipments and finally the laboratory optical performances over the field of view.
Development of multi-spectral lenses for thermal imaging technique
Sergey N. Bezdidko, Elena I. Morozova, Yuri A. Roy
The modern level of development of optoelectronic devices requires the creation of optoelectronic devices, providing maximum information content in different weather conditions, day and night. The solution to this problem is possible only through the creation of optoelectronic devices operating in various ranges of the optical spectrum simultaneously (multi-spectral electro-optical devices). The report presents the results of work on the creation of thermal lenses, working simultaneously in two regions of the spectrum of 3-5 microns and 8-12 microns, shows the results of the specific development of such lenses and their aberration characteristics.
Advances in SSL
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Optical transmittance of high-efficiency cavity with photon recycling
A planar-exit lighting surface is not only used in the luminaires but also useful in the display backlights and other illumination systems. Most planar-exit lighting surfaces are made by edge-lit with line light source or 1-D LED array. If it is not edge-lit type, the light source can be two-dimensional, but a cavity is required. In this paper, a high-efficiency cavity providing extremely high energy transmittance with photon recycling is reported and demonstrated. The cavity contains a diffuser and the high reflectivity surfaces. The optical efficiency of the cavity is calculated by a formula with considering photon recycling. Furthermore, various kinds of diffusers are applied to change the optical transmittance as well as the light pattern. When the reflectivity of the inner wall of the lighting cavity is about 96 %, the optical efficiency of the cavity is higher than 90 % with several diffusers. The experimental measurement as well as the calculation is demonstrated in the paper.
Optical design of the focal adjustable flashlight based on a power white-LED
Jhih-You Cai, Yi-Chien Lo, Ching-Cherng Sun
In the paper, we design a focal adjustable flashlight, which can provide the spotlight and the wide-angle illumination in different modes. For most users, they two request two illumination modes. In such two modes, one is high density energy of the light pattern and the other is the uniform light pattern in a wide view field. In designing the focal adjustable flashlight, we first build a precise optical model for the high-power LED produced by CREE Inc. in mid-field verification to make sure the accuracy of our simulation. Typically, the lens is useful to be the key component of the adjustable flashlight, but the optical efficiency is low. Here, we introduce a concept of so-called total internal refraction (TIR) lens into the design of flashlight. By defocusing the TIR lens, the flashlight can quickly change the beam size and energy density to various applications. We design two segments of the side of the TIR lens so that they can be applied to the two modes, and the flashlight provides a high optical efficiency for each mode. The illuminance of the center of light pattern at a distance of 2 m from the lamp is also higher than using the lens in the spotlight and wide-angle illumination. It provides good lighting functions for users.
High energy-efficient B+R LED beam shaping with micro-lens diffuser for agricultural lighting
Yu-Yu Chang, Xuan-Hao Lee, Ching-Cherng Sun
An energy saving LED luminaire for agricultural lighting is presented in this paper. To improve the traditional agricultural lightings, the beam shaping technology is required. The LED luminaire is composed of three parts, LEDs, collimator, and micro-lens diffuser. In this paper, the advantages of the LED luminaire are obvious, including uniform and energy saving. With a comparison for traditional agricultural lightings, the LED luminaire can save 63 % in energy consumption.
Lens Design and Optical Engineering II
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Range-balancing the Large Binocular Telescope
A. Rakich, D. Thompson, O. P Kuhn
The Large Binocular Telescope (LBT) consists of two 8.4 m telescopes mounted on a common alt-az gimbal. The telescope has various modes of operation, including prime-focus, bent- and direct-Gregorian modes. The telescopes can feed independent instruments or their light can be combined in one of two interferometric instruments, giving an interferometric baseline of over 22 m. With all large telescopes, including the LBT, collimation models or modeled values for hexapod positions, are required to maintain reasonable optical alignment over the working range of temperatures and telescope elevations. Unlike other telescopes, the LBT has a highly asymmetric mechanical structure, and as a result the collimation models are required to do a lot more "work", than on an equivalent aperture monocular telescope that are usually designed to incorporate a Serurrier truss arrangement. LBT has been phasing in science operations over the last 5 years, with first light on the prime-focus cameras in 2006, and first light in Gregorian mode in 2008. In this time the generation of collimation models for LBT has proven to be problematic, with large departures from a given model, and large changes in pointing, being the norm. A refined approach to generating collimation models, "range balancing", has greatly improved this situation. The range-balancing approach to generating collimation models has delivered reliable collimation and pointing in both prime focus and Gregorian modes which has led to greatly increased operational efficiency. The details of the range-balancing approach, involving the removal of pointing "contamination" from collimation data, are given in this paper.
Advanced optical design for DNA sequencing systems
Recent advances in DNA sequencing techniques require the development of high NA immersion microscope systems with large field-of-view, increased resolution and very tight distortion correction. This paper discusses the optical design and tolerance analysis of a NA 1.0 immersion microscope system with a field of view over 1 mm, which is to be used for four-color fluorescence spectroscopy. The microscope system includes an immersion objective lens and four tube lenses, and is corrected for a wide wavelength range from 490 nm to 712 nm. We will discuss critical aspects of designing this kind of optical system, including special glass selection required for chromatic correction.
Development and experimental verification of an intraocular scattering model
Chong-Jhih Jiang, Tian-Siang Jhong, Yi-Chun Chen, et al.
An intraocular scattering model was constructed in human eye model and experimentally verified. According to the biometric data, the volumetric scattering in crystalline lens and diffusion at retina fundus were developed. The scattering parameters of cornea, including particle size and obscuration ratio, were varied to make the veiling luminance of the eye model matching the CIE disability glare general formula. By replacing the transparent lens with a cataractous lens, the disability glare curve of cataracts was generated and compared with that of transparent lenses. The MTF of the intraocular scattering model showed nice correspondence with the data measured by a double-pass experiment.
Linear systems formulation of image analysis in the presence of both aberrations and surface scatter
Narak Choi, James E. Harvey
Image analysis in the presence of surface scatter due to residual optical fabrication errors is often perceived to be complicated, non-intuitive and computationally intensive. The linear systems formulation of surface scatter phenomena has resulted in the development of an angle spread function that is completely analogous to the point spread function in modern image formation theory; i.e., surface scatter can be treated very similar to conventional wavefront aberrations. For multi-element imaging systems degraded by both surface scatter and aberrations, the composite point spread function is obtained in explicit form in terms of convolutions of the geometrical point spread function and the angle spread functions of the individual surfaces of the imaging system. The approximations and assumptions in this formulation are discussed in detail, and the result is compared to the irradiance distribution obtained using commercial software for the case of a two-mirror EUV telescope. The two results are virtually identical.
Thin Film Optical Coating
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Transmission losses in infrared anti-reflection coatings due to water absorption
C. J. Panetta, P. D. Fuqua, C.-T. Chu, et al.
Infrared optical systems require a range of exotic materials, many with large indices of refraction. The mismatch in the index between the optical element and the surrounding medium can result in reflection losses that approach 50%. Antireflection (AR) coatings are applied to these elements in order to minimize "ghost" reflections and improve the optical transmission through a system. The coatings are designed to be highly transparent; however, significant infrared absorption has been observed in some AR coatings. Likely candidates for the loss mechanism are water trapped into the optical coatings during deposition and water being incorporated into coating voids or grain boundaries during exposure to ambient humidity. Five different AR coatings have been procured from four manufacturers to study the cause of the observed losses. Upon receipt of the coated samples, infrared transmission measurements were made which showed the presence of incorporated water/hydroxyl, as evidenced by reduced transmission around 2.9 μm. Four of the five sample types placed in laboratory air for two months continued to absorb water, whereas those placed in flowing dry nitrogen showed no change. Samples placed in a humid environment for one, three and ten days also showed additional water incorporation with the magnitude of the change in transmission on the order of that observed with the two-month air exposure.
Design Methods and Techniques
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Design of a free-form lens system for short distance projection
Bo Yang, Kan Lu, Wei Zhang, et al.
A free-form lens system design is proposed for short distance projection. Free-form surface shape and non-rotational symmetrical structure provide us more freedoms for optimization. The catadioptric structure is also used to reduce the overall length of the whole system. The designed projector lens system consists of two parts. The first part is a rotationally symmetrical lens system which corrects the basic aberrations. The second part contains a free-form lens and a reflector which correct the distortion and other aberrations. We achieve 55inch projected image size at a display screen which is 300mm away from the lens system. The maximum distortion for all fields at all distances is less than 3%.
Progress in the SMS design method for imaging optics
In this work, two SMS algorithms are presented for an objective design with different selected ray-bundles: three meridian ray-bundles (3M) and one meridian and two skew ray-bundles (1M-2S), the latter from pin hole point of view, provides a better sampling of the phase space. Results obtained with different algorithms will be compared.
Distributed wavefront coding for wide angle imaging system
The emerging paradigm of imaging systems, known as wavefront coding, which employs joint optimization of both the optical system and the digital post-processing system, has not only increased the degrees of design freedom but also brought several significant system-level benefits. The effectiveness of wavefront coding has been demonstrated by several proof-of-concept systems in the reduction of focus-related aberrations and extension of depth of focus. While previous research on wavefront coding was mainly targeted at imaging systems having a small or modest field of view (FOV), we present a preliminary study on wavefront coding applied to panoramic optical systems. Unlike traditional wavefront coding systems, which only require the constancy of the modulation transfer function (MTF) over an extended focus range, wavefront-coded panoramic systems particularly emphasize the mitigation of significant off-axis aberrations such as field curvature, coma, and astigmatism. The restrictions of using a traditional generalized cubic polynomial pupil phase mask for wide angle systems are studied in this paper. It is shown that a traditional approach can be used when the variation of the off-axis aberrations remains modest. Consequently, we propose to study how a distributed wavefront coding approach, where two surfaces are used for encoding the wavefront, can be applied to wide angle lenses. A few cases designed using Zemax are presented and discussed
Progressive addition lens design by optimizing NURBS surface
Yen-Liang Liu, Wei-Yao Hsu, Yuan-Chieh Cheng, et al.
Progressive addition lenses (PAL) are used to compensate presbyopia, which is induced by losing accommodation of elder eyes. These eyes need different optical power provided by eye glasses while watching objects at different distance. A smaller optical power is required in further distance and a larger one in nearer zone. A progressive addition lens can provides different power requirements in one piece of lens. This paper introduces a whole process of PAL production, from design, fabrication, to measurement. The PAL is designed by optimizing NURBS surface. Parameters of merit function are adjusted to design lenses with different specifications. The simulation results confirm that the power distributes as expected and cylinders are controlled under an acceptable level. Besides, sample lenses have been fabricated and measured. We apply precise-machining to produce the molds for plastic injection. Then, the samples are produced by injecting polycorbonate to the molds. Finally, Ultra Accuracy 3D Profilemeter is used to measure the sample PALs. Practical examinations shows that our designs are achievable and feasible in practice use.
Poster Session
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Testing and design of a low-cost large scale solar simulator
Qinglong Meng, Yuan Wang
To simulate solar radiation at the earth's surface, a new economical multiple-lamp solar simulator was designed. The solar simulator is comprised of 188 reflector sunlight dysprosium lamps whose light spectrum is very similar to air mass 1.5 (AM1.5) solar spectrum terrestrial standards. Lamps are configured in a hexagonal pattern with 15 columns of 12 or 13 lamps at a lamp-to-lamp spacing and column-to-column spacing of 295mm. Without altering the radiation spectral distribution, the average irradiance on target irradiated area can be adjusted over a wide range between 150 and 1100W/m2 by means of the variation of lamps number or/and lamp-to-irradiated area distance. At the height of 2.0m the solar simulator provides 2m×1.5m irradiated area with over 1000 W/m2. Measurement of irradiance indicates that the multiple-lamp simulator conforms to Class B of ASTM (American Society for Testing and Materials) Standard (ASTM E927-2005) in regard to spectrum match, irradiance uniformity and stability. To enlarge the effective irradiated area, two large mirror-like stainless steel plates was mounted on both of the long sides of the solar simulator. The radiation characteristics of simulator are improved and the optimized effectively irradiation surface is expanded up to 81.6%.
Effects of substrate heating and vacuum annealing on optical and electrical properties of alumina-doped ZnO films deposited by DC magnetron sputtering
Alumina-doped zinc oxide (AZO) films have wide range of applications in optical and optoelectronic devices. AZO films have advantage in high transparency, high stability to hydrogen plasma and low cost to alternative ITO film. AZO film was prepared by direct-current (DC) magnetron sputtering from ceramic ZnO:Al2O3 target. The AZO films were compared in two different conditions. The first is substrate heating process, in which AZO film was deposited by different substrate temperature, room temperature, 150 °C and 250 °C. The second is vacuum annealing process, in which AZO film with deposited at room temperature have been annealed at 250 °C and 450 °C in vacuum. The optical properties, electrical properties, grain size and surface structure properties of the films were studied by UV-VIS-NIR spectrophotometer, Hall effect measurement equipment, x-ray diffraction, and scanning electron microscopy. The resistivity, carrier mobility, carrier concentration, and grain size of AZO films were 1.92×10-3 Ω-cm, 6.38 cm2/Vs, 5.08×1020 #/cm3, and 31.48 nm respectively, in vacuum annealing of 450 °C. The resistivity, carrier mobility, carrier concentration, and grain size of AZO films were 8.72×10-4 Ω-cm, 6.32 cm2/Vs, 1.13×1021 #/cm3, and 31.56 nm, respectively, when substrate temperature was at 250 °C. Substrate heating process is better than vacuum annealed process for AZO film deposited by DC Magnetron Sputtering.
The research of relationships between residual stress and columnar angles in oblique deposition of magnesium fluoride thin films
Cheng-Chung Jaing, Ming-Chung Liu, Wen-Hao Cho, et al.
MgF2 films are obliquely deposited on glass substrates using a resistive heating Mo boat at both substrate temperatures of room temperature and 220 °C. These films have obviously columnar microstructures from SEM pictures without respect to substrate temperatures. The columnar angles of the MgF2 films increase with the deposition angles. However, the columnar angle of MgF2 film, deposited at a substrate temperature of room temperature, is not equal to that at 220 °C when the MgF2 films are prepared at the same deposition angle. Also, the trend of stress behavior of the MgF2 films, deposited at a substrate temperature of room temperature, is different from that at 220 °C due to the generation of thermal stress. The behaviors associated with stress in the MgF2 films are measured using a phase-shifting Twyman-Green interferometer with the application of a phase reduction algorithm. Anisotropic stress does not develop in the MgF2 films with tilted columns and the residual stress depends on the deposition and columnar angles in columnar microstructures of the MgF2 films.
The design of beam shaping focused lens applied in solar energy concentration
In this paper, we proposed a new configuration of concentrator in solar PV system. A special optical system in the concentrator used in focusing sun light to solar cell is proposed, the system compose of an aspherical surface and a specific diffusing surface. The uniform-squared light pattern is obtained on the solar cell, the shape and size of light pattern can be modulated by the parameters of the diffusing surface. In order to decrease the weight of the lens, the concentrator in Fresnel lens type is built at last. Besides, the optical efficiencies formed by the aspherical concentrator and Fresnel concentrator are about 92% and 77%, the concentrations are about 720mW/mm2 and 640mW/mm2, and the acceptance angles are about 0.35° and 0.30°, respectively. The tolerances in assembling the component of the concentrator are also discussed in detail.