大口径平面光学元件波前梯度数控抛光  

Large aperture optical element wavefront gradient controlled by computer numerical controlled polishing

作　　者：黄金勇[1] 赵恒[1] 胡庆[1] 高胥华[1] HUANG Jin-yong;ZHAO Heng;HU Qing;GAO Xu-hua(Chengdu Fine Optical Engineering Research Center, Chengdu 610041, China)

机构地区：[1]成都精密光学工程研究中心

出　　处：《光学精密工程》2019年第7期1473-1480,共8页Optics and Precision Engineering

基　　金：国家863高技术研究发展计划资助项目

摘　　要：针对改善光学元件的波前梯度均方根指标,在总结面形精度及面形分布对波前梯度指标影响规律的基础上,提出了基于匀滑面形拟合加工的方法,给出了该方法的基本思想和工作流程。首先,对原始面形数据进行扫描计算,标记波前突变数据。然后,采用NURBS拟合算法重构相邻面形突变点之间的数据,生成用于指导加工的面形数据。最后,根据待加工面形数据选择相应参数进行面形加工。采用多件610mm×440mm口径K9材料平面反射镜进行实验验证。实验结果表明,使用该方法进行数控加工,在2~3个加工周期内可使波前梯度均方根指标从11nm/cm收敛至7.7nm/cm以内,且面形几乎保持不变。To improve the Graphical Representation of Model Spaces (GRMS) index of optical elements, a new polishing method based on smoothing surface shape by fitting was proposed after the rules of the effects of surface shape precision and distribution on the wavefront gradient index were summarized. The fundamentals and workflow of this method were then presented. First, the surface shape discontinuity was determinedby scanning and computing the original surface shape data. Then, the new surface shape data used in guiding the processing were generated using the non-uniform rational B-spline fitting algorithm and the data between the neighbor discontinuities was reconstucted. Finally, appropriate processing parameters were established based on the generated surface shape data. An experimental study was conducted on K9 material plane mirrors of 610 × 440 mm, and results showed that the proposed method can reduce the GRMS from 11 nm/cm to less than 7.7 nm/cm in two polishing cycles while maintaining a high surface shape precision.

关 键 词：光学加工 光学元件 数控抛光 波前梯度均方根 匀滑面形拟合 

分 类 号：TG74[金属学及工艺—刀具与模具]