航天相机非球面光学元件的离子束抛光工艺研究

Application of Ion Beam Figuring Technology on Aerospace Camera Aspheric

介绍了某型号航天相机中一块Φ305mm大相对孔径(F#1.3)二次凸非球面反射镜的离子束抛光工艺方法。通过去除函数长时间稳定性分析实验,确认了RF60和RF40两种规格的离子源工艺参数,其所产生的去除函数的PV峰值去除率稳定性分别为3.71%和4.5%。对低入口面形精度的凸非球面反射镜,经过三轮离子束抛光,其面形精度从初始的PV=1.302λ、RMS=0.201λ提高至PV=0.157λ、RMS=0.013λ,满足了型号设计要求。

The process of ion beam figuring for a conic convex aspheric with large relative aperture F1.3 and Ф305mm diameter were discussed. A long time remove function stability experimental was analyzed to determine the optimized ion beam source setting parameters for RF60 and RF40, the maximum etch height PV error of which was respectively 3.71% and 4.5%. The convex mirror with lower initial surface figure error was polished by ion beam plant, before ion beam figuring, surface figure error of the convex mirror is 2.817λ p-v, 0.313λrms, and is improved to 0.239λ p-v, 0.014λrms after three process iterations. The results satisfy original design requirements.