【作者】 史玲娜；

【导师】 黄尚廉； 潘英俊；

【作者基本信息】 重庆大学 ， 仪器科学与技术， 2009， 博士

【摘要】 随着数字技术的发展,将MEMS技术与空间光调制器相结合,开发基于MEMS技术的光调制器已经成为投影显示领域的研究热点;另一方面,大功率LED由于其突出的优点在近些年发展迅速,将大功率LED作为微投影显示系统的新光源正在被积极研究中。目前,市场上主要微投影显示产品的核心技术大都受到国外专利保护,因此,开发具有自主知识产权的基于MEMS技术的光调制器,并利用LED光源的优势设计相应的光学系统进行投影显示,对打破国外产品的技术垄断,提升我国在显示技术的水平和核心竞争力方面具有重要的科学意义。本文分析和研究的出发点是针对课题组提出的新型光栅光调制器,设计用LED作为其光源的光学投影系统,通过仿真设计和实验来分析研究这一投影显示系统。本文作者在课题组前期工作的基础上进一步详细分析了用LED作为光栅光调制器照明光源的可行性;设计了在LED照明下的光栅光调制器的照明聚光系统和投影成像系统,并对设计作出评价;利用设计结果搭建了实验平台,验证了理论和设计的正确性。具体研究内容包括:1)在光栅光调制器调制原理的基础上进一步分析了器件的表面弯曲度和周期性结构对器件调制特性的影响,优化了光栅光调制器的理论光学模型,为光栅光调制器的设计及加工工艺提出了改进方案。2)利用部分相干光理论分析了将LED作为光栅光调制器照明光源用于投影显示的可行性。讨论了光源的尺寸、光谱带宽、表面结构对器件调制特性的影响,分别从频谱面的衍射光强分布,像面的光场分布和调制对比度等角度进行说明,分析了LED光源照明下的两种光学信息处理系统,从理论上证明了LED用于光栅光调制器照明光源进行投影显示的可行性,并以此指导光学投影系统的设计。3)利用色度学原理分析了LED光源的色度学特性,分析了RGB三基色LED光源的数目之比、光源带宽变化对显示质量的影响,得到了在三基色LED光源照明下光源的最佳配比方案,并进一步通过显色指数说明LED用于投影显示的性能优异性。4)利用Tracepro、Codev等光学软件,设计了一种自由曲面TIR透镜实现LED光能量的收集;通过直形光棒和梯形光棒两种方案实现了光场的均匀化,并对两种光棒在实现光场均匀化和改善出射光出射角方面进行比较;利用一套结构紧凑的聚光透镜组实现光能量的高效会聚,实现了大发散角的LED光能量的有效收集,并达到了器件的均匀照明。5)依据光栅光调制器的光学调制原理和光学成像原理,确定了投影物镜的类型,利用Zemax、Codev软件设计了两种不同结构的投影物镜组,实现了光栅光调制器的信息处理和投影成像,并通过像差评价对两种结构的投影成像系统进行比较。利用X棱镜实现了三基色LED的彩色合成,最终实现了结构小巧的基于LED光源的光栅光调制器的光学投影系统的计算机仿真设计、建模和评价,掌握了光学投影系统设计的理论基础及关键技术问题的解决方法。6)利用基于MEMS技术加工得到的光栅光调制器,从实验上验证了器件的弯曲度和周期性结构对调制特性的影响,说明理论分析的正确性;根据光学投影系统设计思想搭建实验平台,得到了LED照明下器件的衍射图样分布,并利用一个静态的MEMS光栅光调制器成像,在屏幕上得到该器件的投影图像,用三基色LED搭建了光栅光调制器的彩色投影系统,实现了LED光源照明下的彩色投影显示,说明了理论分析的正确性及仿真设计的合理性。从而率先在国内根据自主研制的基于MEMS技术的光栅光调制器结合LED光源的优势设计了一套全新的光学投影成像系统。更多还原

【Abstract】 With the development of digital technique, it has become a research focus in the area of projected display, which combines MEMS-technique with spatial light modulator to develop light modulators based on MEMS-technique; on the other hand, high-power LED has developed rapidly because of its notable virtue, and using high power LED as new light source for micro-projection display system is being researched actively. Nowadays, the major core technology of micro-projection display system in market is restricted by international patents, so it is quite necessary to develop a novel MEMS-based light modulator with independent intellectual property rights, taking advantages of LED to design corresponding light system for projection display, breaking up the monopoly of techniques of abroad products, and advancing the level and core-competitiveness in the area of display technique of our country.Based on a novel grating light modulator put forward by project’s team, in this paper, an optical projection system is designed when LED is used as its light source, the system is analyzed and researched by simulations and experiments. On the basis of previous foundation of project’s team, author analyzed the feasibility in detail when LED is used as the light source of grating light modulator, designed and evaluated the light condenser system and projection system with LED light source, built the experimental platform utilizing the result of design and proved the validity of theory and design. The main works of this paper are follows:①Based on the principle of grating light modulator, the optical model is optimized after the effects of the surface bending and the periodic structure of grating light modulator on the performance are analyzed, and an optimized precept for design and processing technique is brought forward.②The feasibility is analyzed by partial coherent light theory when LED is used as light source of the grating light modulator for projection display. The influences of the size, bandwidth and surface structure of LED on the modulating performance of the modulator are discussed. That are indicated by the light distribution on the spectrum and image plane and modulated contrast respectively. Two kinds of light information processing systems with LED light source are analyzed, the feasibility when LED is used as the light source of the grating light modulator for projection display is proved theoretically. That could direct the design of optical projection system. ③The colorimetric property of LED is analyzed with colorimetric theory, the influence of the ratio of the number of RGB light source and variety of bandwidth of light source on display quality are analyzed, and the optimal ratio of RGB light source is deduced with the irradiation of LED, and the high performance is illuminated further by color discrimination index when LED is used to projection display.④A TIR lens with free-form surface for light gather is designed by Tracepro and Codev software. The light field is uniformed by straight light pipe and terraced light pipe, which are compared and discussed in the matter of achieving light field uniform and improving angle of emergence light. A compact condensing lens is designed to realize high efficient converging of light, realize efficient gather of large angle of divergence of LED and uniform irradiation on modulator.⑤The type of projection objective lens is ascertained based on the theory of light modulation of the grating light modulator and the theory of optical imaging. Two different structures of projection objective lens are designed by Zeamx and Codev software, and the information processing and projection imaging of the grating light modulator are realized, the aberration valuation is used to compare the two types of projection imaging systems. The color of RGB LED is composed by X cube, and the simulation, modeling and estimate of compact optical projection system for grating light modulator with LED light source are realized, the theoretical principle of designing for optical engine system and solution for key technical matters are grasped.⑥Utilizing the manufactured grating light modulator based on MEMS technique, the influence of surface bending and periodic structure on the optical performance is testified by experiment, which indicated the validity of theoretical analysis. The experiment platform is built with the design philosophy, and utilizing a static MEMS grating light modulator, the diffractive light distribution and the projection image of modulator are got with LED light source, the color projection system of grating light modulator based on three primary colors of LED is built, and color projection display of LED light source is realized, which indicated the validity of the theoretical analysis and the reasonableness of the design. A truly original optical projection imaging system of grating light modulator based on MEMS technique combing with LED light source is first developed independently in China.更多还原