【作者】 余洪斌；

【导师】 陈海清；

【作者基本信息】 华中科技大学 ， 光学工程， 2005， 博士

【摘要】 针对自适应光学系统应用范围日益扩大过程中,对作为校正单元的可变形反射镜小型化的要求,基于最近几十年发展起来的微机电系统技术,本文着重围绕低能耗、小体积的新型可变形反射镜的建模仿真、设计及加工技术开展了一系列较为系统而深入的研究工作。系统地介绍了微机电系统和自适应光学技术的起源、研究现状和未来的发展趋势。对国内外在可变形反射镜方面所作研究工作的进展情况进行了调研和总结。同时对微机电系统中常用的加工手段、所使用材料的制备方法及性能作了较详细的介绍。基于体硅微加工技术设计并制作了一种新型的采用静电驱动的连续面型可变形反射镜。从薄板理论出发,依次对其结构设计、静态变形和动态响应特性进行了深入地分析。讨论了镜面材料性能以及反射镜相关结构参数如镜面厚度对变形和响应频率的影响关系。同时基于光传输理论,对可变形反射镜所具有的光调制能力进行了模拟。接着对其加工工艺进行了较系统地研究。其间着重针对湿法腐蚀、硅—玻璃阳极键合等若干关键的单项工艺开展了深入的理论探讨和实验研究,开发出了一系列新技术,最终成功完成了边长30mm,拥有49 驱动通道的连续面型可变形反射镜实验样品的加工和一些基本性能参数的测试。设计并制作了一种能实现三种运动模式的分离式反射镜。其中首次提出了一种新型的双T 型梁支撑结构,通过建立力学模型,对其在不同受力情况下所表现出的等效弹性系数进行了推导,在此基础上完成了对性能产生重要影响的关键部位尺寸的设计。针对反射镜的不同变形情况,分别建立了简化分析模型并进行了静力学和静电场耦合的模拟仿真,获得了对应状态下反射镜的静、动态静电驱动特性及自由振动的响应频率特性等一系列重要的机械力学特性和静电致动特性。同时以3×3 微镜阵列的某一工作状况为例,对其光调制性能进行了深入分析并给出仿真结果。制订了一整套两层半表面硅微加工工艺流程,提出采用蜂窝状支撑柱和多层膜结构分别用于解决多层材料沉积过程中的结构表面起伏问题和提高反射镜表面质量。最后对所制备的反射镜在三种工作状态下相应的静态通电变形情况进行了测量并对结果作了简要分析。更多还原

【Abstract】 In order to meet the requirement of the expanding application of the adaptive optics system about the miniature of the corrector, the modeling, design and fabrication for novel deformable mirrors with low power consume and small volume are discussed detailedly based on the MEMS technology developed recently. The origin, current status and development trends of the MEMS and adaptive optics technology are investigated fully, and the research about the deformable mirror allover the world is summarized. Furthermore, the fabrication technique and the preparation and performance of the materials commonly used in MEMS are introduced in detail. A novel electrostatic actuated deformable mirror with continuous facet is designed and fabricated by using silicon bulk micromachining technology. Based on thin plate theory, the structure design, static deformation and dynamic response are analyzed, and the influence of the material property and structure parameters such as the thickness of the mirror plate on the mirror deformation and resonant frequency are also discussed. According to the transmitting theory, the light modulation ability is simulated for this mirror. Then some important processes in the fabrication such as wet etching and silicon-Pyrex anodic bonding are studied, meanwhile, a series of new methods are put forward to improve the device performance. Finally, a mirror with 30mm length and 49 actuators is developed successfully, and some basic characteristics about it are also tested. A segmented mirror with three movement modes is also studied. The double T-shape beam structure used for supporting mirror plate is put forwarded originatively. Based on its physical model, the equivalent spring constants of beam under deferent loading situations are deduced, as a result, the dimensions of some important components are optimized. According to the three actuating modes, the simplified models for mirror are constructed respectively, through which the static and dynamic electrostatic actuating characteristics and resonant frequency under freely vibration are analyzed, and the light modulation result about a 3×3 micro mirror array is also provided. A process flow including a half and two layer of polysilicon is drawn out, and a honeycomb like supporting post and multi-layer structure are designed to solve the surface corrugation caused by multi-step deposition and improve the quality of mirror surface. Finally, the static actuating performance of the fabricated mirror is measured and analyzed briefly.更多还原