检索结果-内蒙古大学图书馆

Conference on current developments in Lens design and optical engineering Xiii

作者： Chen, Ching-Wei Chen, Chia-Ray Ho, Cheng-En Yang, Mei-Yi Chang, Shenq-Tsong Huang, T. M. Natl Space Org NSPO Natl Appl Res Labs Hsinchu 300 Taiwan

ISBN: (纸本)9780819492036

FORMOSAT-5 is the first space program that National Space Organization (NSPO) takes full responsibility for the complete satellite system engineering design including payload(s). FORMOSAT-5 will operate in a sun synchronous orbit at 720-km altitude with 98.28-degree inclination angle. The optical Remote Sensing Instrument (RSI) can provide 2-m resolution panchromatic and 4-m resolution multi-spectral images. A Cassegrain type of RSI with two reflective aspheric mirrors and spherical corrector lens is designed. The space thermal environment is one of the important factors that affect the image quality of a space optical RSI. Thermal deformation of RSI structure and mirrors will impact the optical performance. Some preliminary thermal and opto-mechanical analyses are conducted. The relationship among temperature distributions, thermal deformations and image degradation of on-orbit behaviors are discussed. The thermal induced instabilities are incorporated in optical models (e.g., OSLO) by use of Zernike polynomial coefficients to calculate the system MTF and WFE. Due to different thermal environments, on-orbit optical performances depend on imaging locations. Detailed studies and discussions are done in this paper to identify the major sources of thermal deformations and their impacts on image quality.

关键词： Remote Sensing Instrument (RSI) Cassegrain telescope Zernike polynomial on-orbit MTF WFE

来源：评论

学校读者我要写书评

暂无评论

Eliminating Dewar Narcissus artifacts induced by moving optics in infrared staring focal plane sensors

Eliminating Dewar Narcissus artifacts induced by moving opti...

引用

Conference on current developments in Lens design and optical engineering Xiii

作者： McCulloch, Philip M. Olson, Craig Goodman, Timothy D. L3 Commun Sonoma EO Santa Rosa CA 95403 USA

ISBN: (纸本)9780819492036

Staring infrared imagers have multiple surfaces within the integrated Dewar assembly which contribute to non-traditional Narcissus artifacts. Static non-uniformity correction is insufficient to remove dynamic Narcissus artifacts caused by moving focus or zoom groups. Dynamic Narcissus artifacts often manifest as rings apparent to the human eye, although they may lie near the noise floor of the imager. Moreover, strong field curvature of the Narcissus can complicate diagnosis using paraxial methods. We compare a simple pupil ghost metric to traditional Narcissus metrics and present an experimental case study illustrating how the metric can be used during optimization to eliminate the effect.

关键词： optical design Narcissus staring array infrared optics YNI i/ibar

来源：评论

学校读者我要写书评

暂无评论

design of Large Aperture Four Group Elements Mid-wave Infrared Zoom Lens

Design of Large Aperture Four Group Elements Mid-wave Infrar...

引用

Conference on current developments in Lens design and optical engineering Xiii

作者： Ji Yiqun Shi Rongbao He Hucheng Shen Weimin Soochow Univ Inst Modern Opt Technol Key Lab Adv Opt Mfg Technol Jiangsu Prov Suzhou 215006 Jiangsu Peoples R China

ISBN: (纸本)9780819492036

Zoom lens with variable focal length is well fit for researching objectives far and near. design of zoom lens working at mid-wave infrared wavelength (7.7-10.3 m) and its view field 10 degrees is presented. Determination of the initial configuration of the variable and the compensate groups are discussed according to the mechanism compensate curves. The compensate group is determined with positive power. Its focal length changes during a large scope, which is from 300mm to 100mm. And the corresponding F number variables from 3.75 to 1.25. So the residual aberration needs to be carefully corrected. The optimized zoom lens is composed of four group elements, and its performance reaches diffraction limited at each focal position.

关键词： optical design mid-wave infrared zoom lens four group elements mechanical compensate curve large aperture

来源：评论

学校读者我要写书评

暂无评论

design and development of bi-directional Viewer

Design and development of bi-directional Viewer

引用

Conference on current developments in Lens design and optical engineering Xiii

作者： Yu, Zong-Ru Ho, Cheng-Fang Liu, Annie Lee, Tai-Wen Lin, Wen-Lung Hsu, Wei-Yao Natl Appl Res Labs Instrument Technol Res Ctr Hsinchu 300 Taiwan

ISBN: (纸本)9780819492036

Bi-directional viewer just likes a lens of camera. Unlike conventional camera lens, the bi-directional viewer captures not only front view but also side view around the bi-directional viewer. The barrel of bi-directional viewer was designed to have cuts in the side to allow side light to come through, and we use two aspherical mirrors to receive and change the side light to converge on the main optical path. The front view and side view can be imaged simultaneously on an image sensor. Commercial aspherized achromatic lens and micro video lens were also used to keep the image quality and miniaturize the size of the bi-directional viewer respectively. We report on the development of bi-directional viewer, including optical design, optical simulation, optomechanics design, fabrication techniques, assembly procedure and performance testing. The MTF of the bi-directional viewer is also measured and discussed in this paper. We successfully design and realize a bi-directional viewer, which can perform 100 lp/mm spatial frequency image in detail above 20% contrast in the 7.6 mm front view area. And we keep the dimensions of this device within 35 mm in total length and phi 20 mm in diameter.

关键词： Bi-directional viewer Side view MTF Catadioptric Dual-view

来源：评论

学校读者我要写书评

暂无评论

Method for determining individual element misalignments in optical systems

Method for determining individual element misalignments in o...

引用

Conference on current developments in Lens design and optical engineering Xiii

作者： Oteo, Esther Diaz, J. A. Arasa, J. Tech Univ Catalonia Terrassa Spain

ISBN: (纸本)9780819492036

A new method for the misalignments calculation has been developed based in the analysis of the coefficients of the Zernike polynomial adjustment to the on-axis wavefront of the optical system. By means of a study of the system behavior in front of misalignments when they are small perturbations of position around the nominal value, it is shown that the Zernike coefficients behaviour can be aproximated with a polynomial. The coefficients of the Zernike polynomial are used to form a system of non-linear equations where the unknown variables are the misalignment values. This system of equations can be solved to find the misalignments values. The method has been validated by the simulation of a triplet where the second lens is misaligned. A series of misalignments of decentering and tilt have been applied and by simulation the wavefront have been obtained. Then the method has been used to calculate the misalignments from the wavefronts. Good results have been obtained for decentering and tilt separetely. With this process, the error of calculation for the tilt and the decentering has been obatined to be less than 20% for the simulated triplet system.

关键词： optical systems elements alignment misalignments Zernike Coefficients wavefront evaluation

来源：评论

学校读者我要写书评

暂无评论

Thermal optical Path Difference Analysis of Off-Axis Lens Ray Trace Foot-Print at Cassegrain telescope correct lens assembly

Thermal Optical Path Difference Analysis of Off-Axis Lens Ra...

引用

Conference on current developments in Lens design and optical engineering Xiii

作者： Hsu, Ming-Ying Lin, Yu-Chuan Chan, Chia-Yen Lin, Wei-Cheng Chang, Shenq-Tsong Huang, Ting-Ming Natl Appl Res Labs Instrument Technol Res Ctr Hsinchu 300 Taiwan

ISBN: (纸本)9780819492036

The Cassegrain telescope system in this study, is discussion correct lens thermal OPD (optical Path Difference) effect optical performance. The correct lens assembly are includes several components such as correct lens, lens mount, spacer, mount barrel and retainer. The heat transfer from surrounding to the correct lens barrel will causes optical system aberration. Meanwhile, the off-axis rays path of the OPD must consider lens incidence point and emergence point. The correct lens temperature distribution is calculate the lens barrel heat transfer analysis, the thermal distortion and stress are solve by FEM (Finite Element Method) software. The temperature calculation results can be weighting to each incidence ray path and calculate thermal OPD. The thermal OPD on Z-direction can be fitted by rigid body motion and Zernike polynomial. The fitting results can be used to evaluate the thermal effect on correct lens assembly in telescope system.

关键词： OPD FEM Ray trace Off-axis Correct lens

来源：评论

学校读者我要写书评

暂无评论

Digital optical microscope as a sampled imaging system: mathematical description, camera selection and focusing

Digital optical microscope as a sampled imaging system: math...

引用

Conference on current developments in Lens design and optical engineering Xiii

作者： Borovytsky, Volodymyr Nat Tech Univ Ukraine KPI Opt Eng Dept UA-03056 Kiev Ukraine

ISBN: (纸本)9780819492036

The paper presents the mathematical description of an optical microscope with a digital camera and an image processing as an analog-digital-analog imaging system. This description considers a channel of the microscope as a sequence of the linear spatial filters of two dimensional signals. The channel contains an optical system as a low frequency analog filter, a digital camera as a low frequency analog filter with spatial and amplitude discretization and noise generation, a digital linear filter which has to amplify the high frequency harmonics and a restoration unit that plays a role of a two dimensional interpolator. This mathematical apparatus is useful for proper selection of a digital camera which guarantees the maximal field of view with absence of image distortions. The terms like optimal, non-sufficient and non-useful (void) linear magnification of a microscope optical system are expanded from a visual microscopy to a digital one. This mathematical description is also applied for selection of a digital filter for focusing and digital focus extension. The modulation transfer function of this filter should match for the spatial spectrum of observed objects in the zone of spatial harmonics that is most sensitive to defocusing. In this case the maximal sensitivity to defocusing with minimization of influence of noise can be reached.

关键词： imaging system microscope digital camera focusing modulation transfer function digital filter digital focus extension

来源：评论

学校读者我要写书评

暂无评论

True green semipolar InGaN-based laser diodes beyond critical thickness limits using limited area epitaxy

引用

JOURNAL OF APPLIED PHYSICS 2013年第18期114卷 183101-183101页

作者： Hardy, Matthew T. Wu, Feng Hsu, Po Shan Haeger, Daniel A. Nakamura, Shuji Speck, James S. DenBaars, Steven P. Univ Calif Santa Barbara Dept Mat Santa Barbara CA 93106 USA

Semipolar oriented laser diodes (LDs) have fundamental advantages over c-plane oriented LDs, however, the thickness and composition of InGaN waveguiding layers and AlGaN cladding are limited by the onset of stress relaxation via threading dislocation glide on the c-plane slip system. Limited area epitaxy minimizes misfit dislocation (MD) formation by preventing pre-existing TDs from entering a patterned mesa. We examine the effects of mesa height and facet evolution for LAE grown strained layers. Significant MD formation was suppressed by at least a factor of four for Al0.1Ga0.9N/GaN superlattices, enabling AlGaN-clad structures similar to those used in c-plane LDs. We then demonstrate AlGaN-clad blue (456 nm) LDs with threshold current density (J(th)) of 4.5 kA/cm(2) and GaN-clad true green (523 nm) LDs with Jth of 12 kA/cm(2). TEM measurements of the green LD confirm reduction of MD densities with reduction of MD run length. LAE is effective for improving the optical confinement factor of semipolar LDs and offers a glimpse of the design space that may soon be available using low TD density bulk GaN substrates. (C) 2013 AIP Publishing LLC.

关键词： Laser diodes Etching Cladding iii-V semiconductors Semiconductor growth

来源：评论

学校读者我要写书评

暂无评论

Co-extruded Multilayer Films for High Capacity optical Data Storage

Co-extruded Multilayer Films for High Capacity Optical Data ...

引用

Conference on current developments in Lens design and optical engineering Xiii

作者： Christenson, Cory W. Ryan, Chris Valle, Brent Saini, Anuj Lott, Joseph Johnson, Jack Schiraldi, David Weder, Christoph Baer, Eric Singer, Kenneth D. Shan, Jie Case Western Reserve Univ Dept Phys Cleveland OH 44106 USA

ISBN: (纸本)9780819492036

New approaches for optical data storage (ODS) applications are needed to meet the future requirements of applications in multimedia, archiving, security, and many others. Commercial data storage technologies are moving to three-dimensional (3D) materials, but the capacity is limited by the fabrication cost and the number of layers that can be addressed using the reflection-based storage mechanism. We demonstrate here storage systems based on co-extrusion of multilayer (ML) films that can overcome these problems. The organic roll-to-roll films produced can easily be produced hundreds of meters in length, in a far simpler and cheaper manner than current manufacturing methods such as spin coating and lamination. The medium consists of alternating active and buffer layers, and data storage is demonstrated by writing images in 23 layers of 78 mu m thick films by fluorescence (FL) quenching of an organic dye. The areal data resolution is at the diffraction limit of the CW Blu-ray (BR) laser employed, and the co-extrusion technique allows for small layer spacings, leading to a total bit density 1.2 Tb/cm(3). We anticipate materials already demonstrated successful for 3D ODS will be adapted to this technique, as well as new systems developed, to take full advantage of this medium.

关键词： optical data storage extrusion photonics organic chromophore organic polymer photobleaching

来源：评论

学校读者我要写书评

暂无评论

Electrostatic Focusing System with high value of demagnification

Electrostatic Focusing System with high value of demagnifica...

引用

Conference on current developments in Lens design and optical engineering Xiii

作者： Abgaryan, Artush A. Levi, Eli AISC Inc Hauppauge NY 11788 USA

ISBN: (纸本)9780819492036

For E-beam transmission and transforming we developed an electrostatic focusing device with extraordinary demagnification and abilities for 100% transmission of an electron beam with uniform distribution of current density. This experimental electrostatic focusing system consists of two sections;the first is field formation and second is field free -for measurement space(1). The purpose of this article is to present the experimental results from our electro-optical system. The measurement instrument used in the laboratory set up is an adjustable scanning system, which includes a faraday cup with a 14um diameter tungsten wire, for measuring different cross sections. The measurement of the crossover point is based on a combination of theoretical and experimental processes. The theoretical uses calculations from the " CPO"(2) program and the experimental measures different cross sections which are much larger than the diameter of the tungsten wire. Theoretically, from trajectory calculations, the crossover point is approximately 0.446 mu m. This estimation is obtained by drawing an isosceles triangle from the experimental results and comparing it to another isosceles triangle created from the theoretically calculated trajectories. Both triangles together have a geometrically proportional ratio and differ by about one percent or less. The design of the electrostatic focusing system is achieved utilizing the CGMR (Cone and Golden Mean Ratio) approach (1, 3 and 4). This system is suitable for use in X-ray tubes(5), e-beam lithography, SEM, high speed photonic technology, and also for any EOS.

关键词： Electro-optical systems CRT EBL SEM X-Ray tube electro-vacuum devices

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：