高精度平面光学元件全局修形加工方法研究

发布时间：2018-09-19 13:42

【摘要】：平面光学元件是光学系统的重要组成部分,如今光学系统向着大型化、精密化的方向发展,对光学元件的数量和质量均提出了更高的要求。一方面光学系统所需光学元件包括平面光学元件的数量急剧增长,要求光学元件的加工具有较高的效率；另一方面,为了达到较高的成像质量,对光学元件的表面精度要求也越来越高。目前主流的加工工艺很难同时满足这两个方面的需求,所以如何能提高平面光学元件的加工效率并且保证较高的表面质量是当前亟需解决的科研难题之一。空间反射镜轻量化设计引出了陶瓷类材料的广泛应用,但为了克服陶瓷材料本身的缺陷,需要对陶瓷基体进行表面改性处理并对改性层进行加工以达到使用要求。改性层厚度是决定反射镜制造成本的重要因素,因此,在满足使用要求的基础上降低材料去除总量以减小改性层厚度能很大程度上降低反射镜的制造成本。本文立足于以上应用背景,在传统化学机械抛光工艺的基础上提出了一种全局修形加工新方法,阐述了其基本原理和理论依据,通过理论分析建立了全局修形加工系统并进行了试验验证,主要工作内容如下：(1)基于传统化学机械抛光的基本原理,提出了通过去除抛光垫上与抛光垫同心的环形区域,避免该区域与工件表面接触,从而改变材料去除率分布特性以进行表面修形的全局修形加工新方法,并在原理上对该方法进行了阐述。(2)建立了工件径向材料去除率分布趋势预测模型并编写了相应的MATLAB GUI软件程序,以分析工件表面材料去除率在不同修形条件(环形区域位置及宽度)和抛光参数(抛光压力、转速、偏心距等)下的分布趋势。(3)研究了工件表面形貌对材料去除率分布特性的影响,基于实测的材料去除率分布和根据表面实际轮廓分析得到的接触压力,分析了Preston系数在工件表面的分布规律以及随面形的变化规律,研究了材料去除率的可精确预测性。(4)针对Φ100mm玻璃晶圆的修形加工设计了专用的修形加工试验装置,并使用该装置进行了无摆动修形和加摆动修形两组全局修形加工试验,试验结果表明,两种方式的修形均可以大幅改善工件的面形精度,同时,通过两种方式修形结果的对比,表明加摆动修形可以明显改善工件表面沿径向的平滑度,同时,出边修形可以提高加工过程中对边缘效应的修正能力,降低材料总去除量。
[Abstract]:The planar optical element is an important part of the optical system. Nowadays, the optical system is developing towards the direction of large scale and precision, so the quantity and quality of the optical element are required to be higher. On the one hand, the number of optical elements, including planar optical elements, which are needed in optical systems has increased dramatically, which requires the processing of optical elements to have a higher efficiency; on the other hand, in order to achieve a higher imaging quality, The surface accuracy of optical elements is also required higher and higher. At present, the mainstream processing technology is difficult to meet the needs of these two aspects, so how to improve the processing efficiency of planar optical elements and ensure high surface quality is one of the urgent research problems. The lightweight design of space mirror leads to the wide application of ceramic materials, but in order to overcome the defects of ceramic materials, it is necessary to modify the surface of ceramic substrate and process the modified layer to meet the requirements of application. The thickness of the modified layer is an important factor to determine the manufacturing cost of the mirror. Therefore, reducing the total amount of material removal to reduce the thickness of the modified layer can greatly reduce the manufacturing cost of the mirror. Based on the above application background, this paper puts forward a new method of global shape modification based on the traditional chemical mechanical polishing technology, and expounds its basic principle and theoretical basis. Through theoretical analysis, the global shape modification system is established and tested. The main work is as follows: (1) based on the basic principle of traditional chemical-mechanical polishing, the annular region which is concentric with the polishing pad on the polishing pad is removed. Avoiding the contact between the area and the surface of the workpiece, thus changing the material removal rate distribution characteristics to carry out a new method of global profile modification for surface modification, The method is described in principle. (2) the prediction model of radial material removal rate distribution trend is established and the corresponding MATLAB GUI software program is written. In order to analyze the removal rate of workpiece surface material in different shape modification conditions (ring area position and width) and polishing parameters (polishing pressure, rotation speed), (3) the influence of workpiece surface morphology on the material removal rate distribution is studied. Based on the measured material removal rate distribution and the contact pressure obtained from the actual surface profile analysis, The distribution law of Preston coefficient on the surface of workpiece and the variation law with the shape of workpiece are analyzed, and the accurate predictability of material removal rate is studied. (4) A special experimental device for modifying the shape of 桅 100mm glass wafer is designed. The experimental results show that both of the two methods can greatly improve the precision of workpiece profile. At the same time, the comparison of the results of the two ways is given. The results show that the workpiece surface smoothness along the radial direction can be obviously improved by adding swing modification, and the edge effect correction ability can be improved during the machining process, and the total material removal can be reduced.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH74

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