基于卡塞格林系统的红外制冷型长焦分档变倍光学系统的设计

本文基于卡塞格林系统设计了红外制冷型长焦分档变倍光学系统，计算、推导了光学初始参数及组元的光焦度分配。采用了二次成像结构形式，主物镜组采用R-C光学结构用于缩短筒长，使用投影镜组解决冷屏匹配问题，利用调焦镜实现调焦，通过切换投影镜组后组实现变倍，然后对光学系统像差进行了优化设计，分别给出了长焦系统和短焦系统不同视场的成像质量优化结果，0.8视场内光学传递函数在空间频率17 lp/mm时均大于0.4。最后对主要结构进行了相应的精度分析，结果表明该设计能够很好地满足工程实际需要。

Design of cooled infrared switch-zoom optical system with long effective focal length based on R-C system

Based on the R-C system a cooled infrared swith-zoom optical system with long effective focal length is designed. The initial parameters are calculated and the components＇ focal power is deduced. Secondary im- aging structure is adopted, and relay lens is used to match the cold stop. Zoom is realized by switching the re- lay lens of the short focal length system and the long focal length system. The optimized design of optical sys- tem aberration is made. The optimized imaging results of the long effective focal length optical system and the short effective focal length optical system at different field of view are presented, and the modulation transfer functions within 0. 8 field of view at 17 lp/mm of spatial frequency are greater than 0.4. Finally, correspond- ing precision analysis of the main structure is made and the results show that the structure is rational and the imaging quality is good. The optical system can meet actual requirement.