检索结果-内蒙古大学图书馆

Conference on current developments in Lens design and optical engineering XVII

作者： Suarez-Romero, J. G. Solorio-Leyva, J. C. Hurtado-Ramos, J. B. Tecnolo Nacl Mexico lnst Tecnolo Queretaro Tecnolo SN Esq Escobedo Queretaro 76000 Qro Mexico Tecnol Nacl Mexico Inst Tecnol Piedad Tecnol 2000 La Piedad 59370 Michoacan Mexico Inst Politecnico Nacl Centro Invest Ciencia Aplicada Tecnol Cerro Blanco 141 Queretaro 76090 Qro Mexico

ISBN: (数字)9781510602861

ISBN: (纸本)9781510602854;9781510602861

In a previous work, we described the theoretical fundamentals for the design of radiance meters. There, we observed that the length between the first and the second aperture of the instrument plays an important role in the performance of the meter. Such a length is a parameter related with the instrument response to variations of the size of the source and of the distance between the instrument and the source. Such dependences are not predicted by the theory of geometrical optics, normally used in the instrument design. Even the approximation of wave optics gives a partial understanding of the propagation of optical radiation. A more general treatment, based in the theory of partial coherence, gives a better description of the propagation.

关键词： Radiometry Radiance meter Partial Coherence Diffraction Lambertian Source Distance Effect Size of Source Effect Diffraction Corrections

来源：评论

学校读者我要写书评

暂无评论

Reduce Volume of Head-Up Display by Image Stitching 17

Reduce Volume of Head-Up Display by Image Stitching

引用

Conference on current developments in Lens design and optical engineering XVII

作者： Chiu, Yi-Feng Su, Guo-Dung J. Natl Taiwan Univ Grad Inst Photon & Optoelect 1Roosevelt RdSect 4 Taipei Taiwan

ISBN: (数字)9781510602861

ISBN: (纸本)9781510602854;9781510602861

Head-up Display (HUD) is a safety feature for automobile drivers. Although there have been some HUD systems in commercial product already, their images are too small to show assistance information. Another problem, the volume of HUD is too large. We proposed a HUD including micro-projectors, rear-projection screen, microlens array (MLA) and the light source is 28 mm x 14 mm realized a 200 mm x 100 mm image in 3 meters from drivers. We want to use the MLA to reduce the volume by virtual image stitching. We design the HUD's package dimensions is 12 cm x 12 cm x 9 cm. It is able to show speed, map-navigation and night vision information. We used Liquid Crystal Display (LCD) as our image source due to its brighter image output required and the minimum volume occupancy. The MLA is a multi aperture system. The proposed MLA consists of many optical channels each transmitting a segment of the whole field of view. The design of the system provides the stitching of the partial images, so that we can see the whole virtual image. (C) 2016 optical Society of America

关键词： Heads up displays Microlens array Light sources Distortion Eye models LCDs Microlens Night vision optical design Spherical lenses

来源：评论

学校读者我要写书评

暂无评论

optical design and tolerancing of a hyperspectral imaging spectrometer 17

Optical design and tolerancing of a hyperspectral imaging sp...

引用

Conference on current developments in Lens design and optical engineering XVII

作者： Liu, Chang Straif, Christoph Fluegel-Paul, Thomas Zeitner, Uwe D. Gross, Herbert Friedrich Schiller Univ Jena D-07743 Jena Germany DLR Space Adm D-53227 Bonn Germany Fraunhofer Inst Angew Opt & Feinmech D-07745 Jena Germany

ISBN: (数字)9781510602861

ISBN: (纸本)9781510602854;9781510602861

A hyperspectral imaging spectrometer covering the wavelength range from 420 nm to 1000 nm is designed for the purpose of monitoring Earth's environmental change. It has an entrance slit length of 24 mu m, f/# of 3, smile and keystone distortion smaller than 20% of the pixel pitch and a spectral resolution of 6.5 nm. We design and review thirteen systems including one Offner system, two Schwarzschild systems and ten TMA systems for such specifications. Freeform surface and aspheric surface are used in some of the systems to achieve the required system parameters. With all system performance being summarized and evaluated, advantages and disadvantages of three different system types are compared. We down select two systems for further fine adjustments and tolerancing analysis. Final systems with superior performance and detailed tolerancing analysis are given at the end.

关键词： spectrometer TMA Schwarzschild tolerancing

来源：评论

学校读者我要写书评

暂无评论

optical performance of a PDMS tunable lens with automatically controlled applied stress 17

Optical performance of a PDMS tunable lens with automaticall...

引用

Conference on current developments in Lens design and optical engineering XVII

作者： Cruz-Felix, Angel S. Santiago-Alvarado, Agustin Hernandez-Mendez, Arturo Reyes-Perez, Emilio R. Tepichin-Rodriguez, Eduardo Technol Univ Mixteca Inst Phys & Math Carretera Acatlima km 2-5 Mexico City 69000 DF Mexico Natl Inst Astrophys Opt & Elect Dept Opt Mexico City 72840 DF Mexico

ISBN: (数字)9781510602861

ISBN: (纸本)9781510602854;9781510602861

The advances in the field of adaptive optics and in the fabrication of tunable optical components capable to automatically modify their physical features are of great interest in areas like machine vision, imaging systems, ophthalmology, etc. Such components like tunable lenses are used to reduce the overall size of optical setups like in small camera systems and even to imitate some biological functions made by the human eye. In this direction, in the last years we have been working in the development and fabrication of PDMS-made tunable lenses and in the design of special mechanical mounting systems to manipulate them. A PDMS-made tunable lens was previously designed by us, following the scheme reported by Navarro et al. in 1985, in order to mimic the accommodation process made by the crystalline lens of the human eye. The design included a simulation of the application of radial stress onto the lens and it was shown that the effective focal length was indeed changed. In this work we show the fabrication process of this particular tunable lens and an optimized mechanism that is able to automatically change the curvature of both surfaces of the lens by the application of controlled stress. We also show results of a study and analysis of aberrations performed to the Solid Elastic Lens (SEL).

关键词： Tunable lens crystalline lens wavefront aberration function optomechatronic system

来源：评论

学校读者我要写书评

暂无评论

Coronary interventions. current developments for improved long-term results

引用

INTERNIST 2016年第9期57卷 832-843页

作者： Seidler, T. Univ Gottingen Univ Med Gottingen Klin Kardiol & Pneumol Herzzentrum Robert Koch Str 40 D-37075 Gottingen Germany

Based on solid scientific evidence, new generation drug-eluting stents (DES) have become established as the standard of care in interventional cardiology. With at least similar safety and superior efficacy over uncoated bare metal stents (BMS) in various scenarios and including patients with increased bleeding risk, there are probably no remaining indications favoring the use of BMS. Additional developments regarding the platform, drug elution characteristics and polymer design were aimed at optimizing DES with even better outcomes. Although there is no lack of new variations, none has proven to be superior and several non-inferiority trials lacked statistical power, which precludes the label third generation (over second generation or new generation DES). While it is recognized that potential long-term advantages of bioresorbable scaffolds cannot be expected at this stage from the current ABSORB iii trial, the safety and efficacy are encouraging. Beyond procedural aspects, such as intracoronary imaging, variations in duration of antiplatelet therapy should help to improve outcomes but still require careful individual weighting of ischemic vs. bleeding risk.

关键词： Coronary artery disease Percutaneous coronary intervention Drug-eluting stents Tomography, optical coherence Platelet aggregation inhibitors

来源：评论

学校读者我要写书评

暂无评论

Novel microfluidic devices for Raman spectroscopy and optical trapping 17

Novel microfluidic devices for Raman spectroscopy and optica...

引用

Conference on current developments in Lens design and optical engineering XVII

作者： Ottevaere, Heidi Liu, Qing de Coster, Diane Van Erps, Juergen Vervaeke, Michael Thienpont, Hugo Vrije Univ Brussel Dept Appl Phys & Photon Brussels Photon Team Pleinlaan 2 B-1050 Brussels Belgium

ISBN: (数字)9781510602861

ISBN: (纸本)9781510602854;9781510602861

Traditionally, Raman spectroscopy is done in a specialized lab, with considerable requirements in terms of equipment, time and manual sampling of substances of interest. We present the modeling, the design and the fabrication process of a microfluidic device incorporation Raman spectroscopy, from which one enables confocal Raman measurements on-chip. The latter is fabricated using ultra precision diamond tooling and is tested in a proof-of-concept setup, by for example measuring Raman spectra of urea solutions with various concentrations. If one wants to analyze single cells instead of a sample solution, precautions need to be taken. Since Raman scattering is a weak process, the molecular fingerprint of flowing particles would be hard to measure. One method is to stably position the cell under test in the detection area during acquisition of the Raman scattering such that the acquisition time can be increased. Positioning of cells can be done through optical trapping and leads to an enhanced signal-to-noise ratio and thus a more reliable cell identification. Like Raman spectroscopy, optical trapping can also be miniaturized. We present the modeling, design process and fabrication of a mass-manufacturable polymer microfluidic device for dual fiber optical trapping using two counterpropagating single-mode beams. We use a novel fabrication process that consists of a premilling step and ultraprecision diamond tooling for the manufacturing of the molds and double-sided hot embossing for replication, resulting in a robust microfluidic chip for optical trapping. In a proof-of-concept demonstration, we characterize the trapping capabilities of the hot embossed chip.

关键词： Raman spectroscopy optical trapping optics polymer microfluidic confocal detection diamond machining microstructure fabrication

来源：评论

学校读者我要写书评

暂无评论

optical design of an ultrashort throw ratio projector with two freeform mirrors 17

Optical design of an ultrashort throw ratio projector with t...

引用

Conference on current developments in Lens design and optical engineering XVII

作者： Nie, Yunfeng Mohedano, Ruben Benitez, Pablo Chaves, Julio Minano, Juan C. Thienpont, Hugo Duerr, Fabian Vrije Univ Brussel Dept Appl Phys & Photon Brussels Photon Team Pleinlaan 2 B-1050 Brussels Belgium Light Prescript Innovators Madrid 28223 Spain Light Prescript Innovators Altadena CA 91001 USA Univ Politecn Madrid CeDint Campus Montegancedo Pozuelo Madrid 28223 Spain

ISBN: (数字)9781510602861

ISBN: (纸本)9781510602854;9781510602861

In this work, an optical design approach is presented to design an ultrashort throw distance projection system by combination of an off-the-shelf refractive lens and two off-axis freeform mirrors. These two freeform mirrors are used to greatly shorten the projection distance by more than three times compared to conventional (rotationally symmetric) systems, while still maintaining a good imaging quality. Firstly, a direct design method that enables the simultaneous calculation of two off-axis freeform-profile mirrors by partially coupling more than three fields is introduced. The specifications of the conventional refractive lens are taken into account during this procedure. The pupil matching principle is applied to ensure good performance between the two sub-systems. The calculated mirrors then serve as a good starting point for optimization using commercial optical design software. To step from freeform profiles to freeform surfaces, the calculated two profiles are fitted into odd polynomials to evaluate the image quality and then re-fitted into XY polynomials for further optimization. Finally, the polynomial coefficients of the two freeform mirrors are imported into the optical design program. The merit function is built from RMS spot radii over the full field, and additional constraints are made for correcting distortion. After optimization, the calculated initial design quickly converges to a well performing imaging system. As an example, an ultrashort throw distance projection lens with a large 80-inch diagonal image at 400mm throw distance is designed, analyzed and compared with literature data. The values of MTF are over 0.6 at 0.5 lp/mm and the distortion is less than 1.5%: showing a very good and well balanced imaging performance over the entire field of view.

关键词： geometric optics ultrashort throw ratio projector optical design aspheric mirrors freeform optics

来源：评论

学校读者我要写书评

暂无评论

Studying the back-scattering of light for the development of acousto- optical filter with an improved spectral resolution 17

Studying the back-scattering of light for the development of...

引用

Conference on current developments in Lens design and optical engineering XVII

作者： Shcherbakov, Alexandre S. Arellanes, Adan Omar Chavushyan, Vahram Natl Inst Astrophys Opt & Elect INAOE Luis Enrique Erro 1 AP 51 & 216 Puebla 72000 Mexico

ISBN: (数字)9781510602861

ISBN: (纸本)9781510602854;9781510602861

We consider the collinear backward light scattering as one of potential physical mechanisms for creating an advanced collinear acousto-optical filter with significantly improved spectral resolution. Within co-directional crystalline collinear acousto-optical filters, the resolution is inversely proportional to the material's birefringence, which is similar to 0.1 in the best case of LiNbO3-crystal. For the backward light scattering this parameter is replaced by the twice refractive index, so that the gain achieves > 45 times in LiNbO3-crystal. Thus, one can expect the resolution similar to 0.002 angstrom instead of the val similar to 0.1 0.2 recently obtained by us experimentallor co-directional geometry in that crystal. Moreover, the collinear backward light scattering can be implemented in an extended amount of available materials. However, the main limitation for applying the phenomenon is the acoustic attenuation in ultra-high frequency range peculiar to the materials for acousto-optical filters. Linear acoustic attenuation reduces the length of acousto-optical interaction and limits the spectral resolution. At an initial stage, our studies are concentrated on physical aspects of this phenomenon as well as on possibilities of its application to creating the acousto-optical filters of a high resolution. In particular, the frequency band-shapes of the scattered light intensity exhibit a tendency to specific acousto-optical nonlinearity, i.e. to more and more rectangular profile as the acoustic power density grows. Results of this analysis confirm the above-noted estimations for a triplet of trigonal acousto-optical crystals, having possibly lower acoustic attenuation.

关键词： acousto-optics collinear acousto-optical filter backward light scattering improved spectral resolution astrophysical applications

来源：评论

学校读者我要写书评

暂无评论

Stress engineering with silicon nitride stressors for Ge-on-Si lasers

Stress engineering with silicon nitride stressors for Ge-on-...

引用

作者： Ke, Jiaxin University of British Columbia

Silicon compatible lasers are in great need for applications such as on-chip and short-reach optical interconnects. Although InAs/GaAs quantum dot lasers monolithically grown on Si have been realized and are well-performed, due to material contamination issues, it is time and cost intensive for those iii-V materials to enter mainstream Si processing facilities. Germanium(Ge)-on-Silicon(Si) laser is promising as a solution to solve the Si-compatible laser problem as it is compatible with Si processing. So far, the main problems in Ge lasers are that they have a high threshold current density and low efficiency. Laser structure designs with top and side silicon nitride stressors were proposed in this work and shown to be effective in reducing the threshold current (Ith) and improving the wall-plug efficiency (ηwp) of Ge-on-Si lasers. Side stressors turned out to be a more efficient way to increase ηwp than using the top and side stressors together. With the side stressors and geometry optimizations, a maximum ηwp of 34.8% and an Ith of 36 mA (Jth of 27 kA/cm²) were achieved with a defect limited carrier lifetime (??,?) of 1 ns. With ??,? being 10 ?? , an Ith of 4 mA (Jth of 3 kA/cm²) and a ηwp of 43.8% were achieved. These are tremendous improvements from cases without any stressors. Compared to other stress introduction methods, such design is much more suitable for Ge laser structure implementation. These results provide a strong support to the Ge-on-Si laser technology and create an effective way to improve the Ge laser performance.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Characterization of a tunable liquid-filled lens with minimum spherical aberration 17

Characterization of a tunable liquid-filled lens with minimu...

引用

Conference on current developments in Lens design and optical engineering XVII

作者： Diaz-Gonzalez, G. Santiago-Alvarado, A. Munoz-Lopez, J. Juarez-Salazar, R. Cruz-Felix, A. S. Jimenez-Barriga, N. Univ Tecnol Mixteca Carretera Acatlima Km 2-5 Mexico City 69000 DF Mexico Inst Nacl Astrofis Optic Elect Luis Enrique Erro 1 Puebla 72840 Mexico Inst Politecn Nacl CONACYT CITEDI Ave Inst Politecn Nacl 1310 Tijuana 22435 BC Mexico

ISBN: (数字)9781510602861

ISBN: (纸本)9781510602854;9781510602861

Tunable lenses have become very popular elements due their capacity of change their focal length by only modifying their shape. This characteristic is very useful in different applications in the field of optics. The development of tunable lenses consists on several phases: first, to find a suitable material, second, to obtain an optimal analysis and design, and third, to find the way to change the lens shape and characterization. In this work we present the characterization of a tunable lens, formed by spherical profiled elastic membranes and a liquid medium between them. The proposed liquid-filled tunable has a design such that the spherical aberration is the least to different focus. The development of an optomechanical system to change the lens shape is presented.

关键词： Tunable lens liquid filled lens opto-mechanical design

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：