星载激光雷达望远镜主镜光机分析与优化

Optomechanical analysis and optimization of spaceborne lidar telescope primary mirror

针对研制和集成完的直径为1 m的激光雷达望远镜,介绍了望远镜主镜系统的结构设计,并分析了主镜二级背板安装点匹配失调及主镜挠性支撑脚作用对主镜面形的影响。通过建立主镜系统的有限元模型开展光机分析,并对分析结果进行了处理,使其能够与集成装校时的干涉测量波前图进行直接对比,得出二级背板与光学基板安装点匹配失调是导致主镜形变过大的主要原因。针对此问题对望远镜主镜系统结构进行了改进,通过有限元光机结构分析,预计优化后的结构能够有效地减小匹配失调导致的主镜形变,将使主镜均方根形变量从0.3λ降至0.097λ(λ=632.8 nm),满足激光雷达要求的0.15λ面形要求。

Based on the fabricated and assembled lidar telescope, the structure of its primary mirror subsystem was presented. The effects on the primary mirror surface of the mismatch among the assembling points on the second supporting board and the malfunction of the flexible supporting foot on the first board were analyzed. The optomechanical analysis was conducted through establishing the finite element model of the primary mirror, the analyzing results were compared with the measured wave front map during the assembling. According to the analysis, the mismatch of the assembling points on the second baseplate was the main reason to deform the primary mirror surface. The primary mirror subsystem structure was optimized through integrated optomechanical analysis. And the expected root mean square deformation of the primary mirror should be decreased from 0.3λ to 0.087λ, which meets the specification requirement of 0.15λ.