大型光学镜面的多点支撑方案分析

Analysis of the Multi-Point Supporting Scheme for Large Aperture Optical Mirror

在大型光学系统中使用薄型镜面以减轻大口径光学镜面的重量,但由于薄镜面在重力作用下形变严重,需要选择适当的支撑方式来维持光学镜面的面形。通过对支撑方式的分析,采用有限元仿真,讨论了支撑点分布方式、支撑分布位置和支撑点数三方面对镜面形变的影响,从而得出支撑点均匀分布优于非均匀分布;支撑点数一定时,镜面形变主要由支撑点位置决定;10个支撑点以上镜面形变相对较小,继续增加支撑点并不能使镜面最大形变得到显著改善同时会引起镜面波纹起伏增加。

Employing the ultra-thin mirrors in optical system is an effective method to reduce the mirrors＇ weight. However, the shape of ultra-thin mirror distorts severely based on the normal gravity, so the proper supporting scheme should be used to maintain the mirror＇s optical surface. In this paper, the mirror distortion effected by the distribution of the support points, the position of support points and the number of support points were discussed by using finite-element simulation. We can draw the conclusion that the uniform distribution of support points is better than non-uniform distribution, mirror distortion mainly dependents on the support location with certain points, mirror distortion relatively small when support points are over ten and adding support points will cause an increasing of corrugation rather than improve the shape of mirror surface.