碳化硅扫描反射镜支撑结构设计

对尺寸为460 mm×290 mm的SiC扫描反射镜的轻量化和支撑结构的设计进行了研究。基于三角形和矩形的复合轻量化结构,采用镜体背部为开放和封闭相结合的形式,设计了一种新型的扫描反射镜组件。该组件采用侧面支撑方式和轴向柔性结构,有利于消除支撑结构材料热膨胀系数不匹配产生的热应力对镜面面形的影响。有限元方法分析结果表明：反射镜组件在1 g重力载荷和8℃温度变化作用下,反射镜镜面的面形误差RMS值分别为4.5 nm和20.3 nm。该反射镜轻量化形式和支撑结构满足光学成像要求,并可有效提高结构的稳定性,对于大尺寸反射镜组件的设计具有借鉴意义。

Design of kinematic mount for SiC scanning reflective mirror

The SiC scanning reflective mirror with a dimension of 460 mm×290 mm used in a spaceborne optical remote sensor is studied.The composite form of triangle and quadrangle and the combination of open and closed back are explored for the design of lightweight scanning mirror.A new kinematic mount and a flexible structure in axis is taken to hold the mirror around the lateral surface.The flexible structure in axis is used as an interface to the kinematic mount to support the mirror,which can eliminate the impact of thermal stress induced by the mismatch of thermal expansion coefficient among the materials on the mirror surfaces.Optical performance of the mirror is analyzed by using Finite Element Method（FEM）.Results indicate that the surface figure errors are 4.5 nm and 20.3 nm under a gravity load of 1 g and the temperature load change of 8 ℃ in different directions.The results show that the lightweight designing and supporting structure of this scanning reflective mirror meet the requirements of optical imaging,and can improve the stability of structure effectively.It can be an important reference for the design of big size scanning reflective mirror components.