针对某长焦距大口径光电设备的特殊要求, 基于卡塞格林光学折反系统达到了较好的红外成像质量和紧凑的结构尺寸。首先通过计算对红外光学系统进行了初步焦距分配; 然后对卡塞格林反射组件和红外组件进行了分段优化设计, 特别是为克服温度变化对焦距和像质的影响, 在后组设计三片透镜作为调焦组, 保证了成像质量; 最后, 为了消除杂光的影响, 分别对轴上、轴外光线进行追迹并设计了主、次镜遮光罩。设计结果分析表明主要指标均满足设计要求。

According to the special requirements of a large aperture and long focal length optical equipment, better quality of infrared imaging and compact structure was achieved based on Cassegrain optical catadioptric system. Firstly, focal length assignment was calculated. Then, Cassegrain reflect component and infrared component was optimized respectively. Specially, in order to overcome the impact of temperature’s change on focal length and image quality, designed three lenses as focus group. Lastly, the main and subordinate lens’s hoods were designed to eliminate the influence of stray light. The design results show that the main indexes meet the design requirements.