薄膜反射镜的静电成形

Electrostatic deformation of membrane mirrors

利用薄膜反射镜作为太空望远镜主镜是研究大口径、超轻型未来空间光学系统的最新方向之一。基于静电学原理,设计了口径Ф200mm薄膜反射镜静电成形实验系统,该系统包括薄膜反射镜固定装置、电极板装置以及直流高压系统。采用ZYGO干涉仪和莫尔偏折术,分别对薄膜反射镜面形随直流电压的变化情况以及不同电压下薄膜反射镜的顶点曲率半径进行了观察和测量,并与理论值进行了比较和分析。实验结果表明,该系统可有效改变薄膜反射镜的面形。目前,在700V电压下,薄膜反射镜的顶点曲率半径达17.7m。

The membrane mirror used as a primary mirror of the space telescope is one of the most novel technologies of the manufacture of large aperture, ultra-lightweight space-borne optical systems in future. An electrostatic deformation system for a membrane mirror of 200 mm in diameter is designed. It consists of a membrane mirror fixation device, an electrode pad and a high direct current （DC） voltage system. Experiments and analysis of the electrostatic deformation of the membrane mirror are described. The deformation of the membrane mirror induced by the change of DC voltage is observed by ZYGO interferometer. The curvature radii of membrane mirror under different voltages are measured by Moire deflectometry. Experimental results show that the system is feasible for changing the surface profiles of a membrane mirror. As an example, the curvature radius of the membrane mirror of 17.7 m was obtained when the applied voltage was 700 V.