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题名	基于出瞳扩展的头戴显示器关键光学技术研究
作者	呼新荣
学位类别	博士
答辩日期	2015-05
授予单位	中国科学院大学
导师	孙强
关键词	头戴显示器 RSD 出瞳扩展 平板波导
其他题名	Research on Optical Key Technologies of Head-MountedDisplay with an Exit Pupil Expander
学位专业	光学工程
中文摘要	头戴显示器（HMD）是一种将微显示器与成像目镜相结合的小型化近眼目视光学系统，由于能够满足特殊环境下人眼对光学显示信息的实时获取需要而被广泛应用在虚拟现实和增强现实领域。为提升军用HMD系统的对比度调节范围、显示亮度和分辨率等关键性能，业界提出了基于激光微扫描的视网膜扫描显示器解决方案；近些年来，为适应民用HMD系统便携化的急迫需求，又出现了基于平板波导的HMD设计新思路。这些新方案的独特之处在于：均采用出瞳扩展器将小出瞳进行有效的二维扩展，在满足人眼目视要求的同时提升系统性能或实现便携化。本文针对视网膜扫描显示器（RSD）和半透膜阵列平板波导HMD的出瞳扩展关键技术展开理论研究，揭示了出瞳扩展的物理规律，得到了扩展出瞳的有效方法，主要工作可分为两大部分。 （1）通过广泛调研RSD的国外研究现状，深入分析了系统设计思路和各项关键技术难点，从光学系统设计的角度描述了限制出瞳的物理机制。采用衍射积分变换的处理方法对衍射光栅出瞳扩展器和微透镜阵列出瞳扩展器进行了理论研究，为出瞳扩展器的设计提供了理论支撑。通过运用光学仿真手段建模，对比研究了六边形排布单透镜阵列和双透镜阵列的出瞳扩展规律，结果表明双透镜阵列是实现彩色显示RSD出瞳扩展的有效方法，并以15mm出瞳直径为例，验证了出瞳扩展方案的有效性。提出了扩展出瞳的评价模型，为出瞳扩展的评价提供了有效方法。针对微透镜阵列的典型加工方式引入的误差，分别建立了微透镜面形误差模型，研究了不同加工误差对出瞳扩展均匀性的影响，为微透镜的设计和研制提供科学指导。 （2）探讨了平板光波导对头戴显示器便携化设计的独特优势，对其实现目镜系统出瞳扩展的原理和设计思想进行了概括。重点研究了半透膜阵列波导的出瞳扩展方案，采用光线的折射/反射模型进行理论推导，得到了对平板波导的结构约束条件，对初始结构设计具有重要指导意义。提出利用两个互相垂直放置的半透膜阵列波导实现目镜出瞳的有效二维扩展，使得小出瞳目镜即可满足头戴显示器对出瞳的使用需求，在缩小目镜体积的同时减轻了系统重量。采用光学设计软件设计了小出瞳（约2.4mm）目镜光学系统，借助光学仿真软件对目镜和平板波导系统进行了光学仿真，研究了系统最终的成像质量和出瞳辐照度分布规律。设计实例显示，采用简单的球面透镜即可实现出瞳7mm12mm，视场1520，光学原件总重约36g，畸变小于0.13%，各视场MTF在40 lp/mm大于0.58。该研究及设计实例为半透膜波导HMD的进一步研制奠定了基础。
英文摘要	A head-mounted display (HMD) is a miniaturized near-eye visual optical system with a combination of micro-display and imaging eyepiece. It is widely used in fields of virtual reality and augmented reality as it meets the human eyes’ needs of obtaining real-time optical display of information in special environments. To enhance the system performance of a military HMD, such as contrast adjustment range, displays brightness and resolution, the reaserchers proposed a solution of the so called retinal scanning display (RSD) based on the laser micro-scanning display technology. In recent years, in order to adapt to the urgent portable needs of the civilian HMD systems, new design ideas of a HMD based on the optical planar waveguide has emerged. These new protypes of HMD are unique in that: the use of the exit pupil expander which effectively expanding a small exit pupil in two dimensions so that meet the visual requirements of the human eyes, while improving system performance or achieving portability of the whole system. In this paper, key technologies of exit pupil expansion in retinal scan display (RSD) and the HMD with semi-transparent films array waveguide are studied theoretically, which reveals the physical laws of realizing the exit pupil expansion. The effective ways to extend exit pupil has been obtained. The main work can be divided into two parts. (1) Through extensive research study on foreign RSD status, the in-depth analysis of system design ideas and the key technical difficulties are analyzed in detail. The physical mechanisms of exit pupil limits are described on the perspective of optical system design. Two typical exit pupil expanders of binary grating and microlens array are theoretically studied by using a method of diffraction integral transformation. It provides a theoretical support for the design of exit pupil expanders. The exit pupil expanding laws of hexagonal arrangement of both a single lens array and a double lens arrays are comparatively studied by using methods of optical modeling and simulations. Double lens arrays are found as an effective way to extend the color display RSD pupil. Taking an exit pupil diameter of 15mm for example, the validity of the exit pupil expansion is verified. The subjective evaluation model of pupil expansion is proposed which provides an effective method for the evaluation of the expanded exit pupil. Micro-lens surface error models are established where the errors are introduced by the typical microlens array processing methods. The influences on the uniformity of exit pupil expansion by different processing error are studied, which provids a scientific guidance for the design and development of the microlens array. (2) The unique advantages of the planar optical waveguide in a portable HMD design are discussed. The realization of the eyepiece’ eixt pupil extension has been summarized. The study is focus on the exit pupil expansion program based on semi-transparent films array waveguide. The structure constraints of the planar waveguide are theoretically deduced using light refraction and reflection model, which has important theoretical significance to an initial optical design. The mothod of using two perpendicular arrayed planar waveguide to achieve an effective two-dimensional expansion of the eyepiece’ exit pupil is proposed. Using this method meets the optical design demand in exit pupil. Meanwile, the volume of the eyepiece is noteblly reduced. A small exit pupil (about 2.4mm) eyepiece optical system is designed. The eyepiece and planar waveguide system model is simulated in optical software. The quality of the final image and the pupil irradiance distribution of system are studied. The design examples show that it is possible to use only spherical lens to achieve an exit pupil size of 7mm12mm and field of 1520. The weight of optical components is just about 36g. The distortion is less than 0.13% and the MTF at 40 lp / mm of each field of view is greater than 0.58. The research laid the foundation for the further development and design of semi-transparent films array waveguide HMD.
公开日期	2015-12-24
内容类型	学位论文
源URL	[http://ir.ciomp.ac.cn/handle/181722/48842]
专题	长春光学精密机械与物理研究所_中科院长春光机所知识产出
推荐引用方式 GB/T 7714	呼新荣. 基于出瞳扩展的头戴显示器关键光学技术研究[D]. 中国科学院大学. 2015.

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