低温红外离轴三反准直系统设计  

Design of low temperature infrared off-axis three-mirror collimation system

作　　者：李文雄 申军立[1,3] 张星祥 陆振玉[1,3] 李志胜[4] 韩哈斯敖其尔 吴清文 LI Wenxiong;SHEN Junli;ZHANG Xingxiang;LU Zhenyu;LI Zhisheng;HAN Hasiaoqier;WU Qingwen(Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China;University of Chinese Academy of Sciences,Beijing 100049,China;CAS Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System,Changchun 130033,China;Beijing Leyfond Vacuum Tech.co.,LTD,Beijing 100024,China)

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [2]中国科学院大学,北京100049 [3]中国科学院空间光学系统在轨制造与集成重点实验室,吉林长春130033 [4]北京胜泰东方科技有限公司,北京100024

出　　处：《光学精密工程》2023年第9期1285-1294,共10页Optics and Precision Engineering

基　　金：国家自然科学基金青年基金资助项目(No.52005478)。

摘　　要：为实现真空100 K低温环境中的红外设备测试,设计了一种离轴三反式的准直系统。该系统采用无热化设计,整机结构选用SiC材料,在镜体与支撑结构连接处采用C形开口胀销作为柔性结构,补偿连接结构的低温变形。系统整体除反射镜外,其余部分全部包裹在低温辐射冷板内。低热导绝热支撑结构在热传导链中起热屏蔽作用,实现系统的绝热支撑和快速制冷。在100 K低温环境下对单镜进行仿真分析,主、次、三镜的面形误差均小于λ/50;整机分析得到主、次、三镜的面形误差均不大于λ/30。常温下系统各个视场波前差在λ/14~λ/8内,低温下系统视场波前差在λ/8~λ/7内,根据瑞利判据可认为波面无缺陷。当λ=632.8 nm时,常温下系统在50 lp/mm频率的调制传递函数(Modulation Transfer Function,MTF)大于0.7;低温下的MTF大于0.6,满足系统在50 lp/mm MTF大于0.6的使用要求。仿真结果表明,准直系统可以在100 K真空环境中稳定输出平行光,满足低温红外设备的测试需求。在快速辐射制冷材料级实验中,历经18 h,温度稳定在130 K;历经30 h,SiC镜坯温度稳定在110 K。该实验验证了SiC反射镜快速辐射制冷的可行性。An off-axis three-mirror collimating optical system is designed to test the infrared equipment in a vacuum 100-K cryogenic environment.The system adopts athermal design,and the whole structure adopts SiC material.A C-shaped opening expansion sleeve is used as a flexible structure to compensate for low-temperature deformation at the connection between the mirror body and the support structure.The whole system is partially wrapped in a radiation cooling panel,except for the reflecting mirror.The low-thermal conductivity thermal insulation support structure plays a thermal shielding role in the heat conduction chain to realize the thermal insulation support and rapid refrigeration of the system.In the 100-K low-temperature environment,according to a system simulation analysis,the primary,secondary,and tertiary mirror wavefront error is<λ/50;an analysis of the whole structure indicates that the wavefront errors of the primary,secondary,and tertiary mirrors are≤λ/30.The wavefront error of each field of view of the system is in the range ofλ/14-λ/8 at room temperature and in the range ofλ/8-λ/7 at 100 K.According to the Rayleigh criterion,the wavefront is considered to be flawless.Whenλ=632.8 nm,the modulation transfer function(MTF)of the system at a 50 lp/mm frequency is>0.7 at room temperature;at a low temperature,the MTF is>0.6.Meet the system at 50 lp/mm greater than 0.6 use requirements.The results indicate that the collimating optical system can output parallel light stably in a 100-K vacuum environment to meet the test requirements of low-temperature infrared equipment.In a material level test of fast radiation cooling,the temperature of the SiC mirror blank is stable at 130 K after 18 h.After 30 h,the mirror blank temperature stabilizes at 110 K.The experiment verifies the feasibility of fast radiation cooling of the SiC mirror.

关 键 词：光学系统设计 准直系统 离轴三反系统 红外 光机热分析 低温 

分 类 号：TH74[机械工程—光学工程]