为了使红外镜头能够在宽的温度范围内工作, 在红外光学系统的设计时就要充分考虑热对光学性能的影响, 并要进行光机热集成分析。论述了光机热集成分析方法及流程, 并设计了一个焦距f=200 mm的冷光栏匹配的宽工作温度的红外镜头。建立了红外镜头的有限元模型并进行了热力学分析, 对分析的镜面变形结果数据进行了处理, 得到各镜片间隔和面形变化, 代入光学软件得到了热环境对光学成像质量的影响。分析结果表明, 对于-40℃~+60℃红外镜头的各个视场, 16线对的调制传递函数都大于0.5, 具有良好像质。所设计的红外镜头结构简单可行, 能够满足设计要求。

In the design of infrared optical system, the impact of thermal effect on optical performance should be taken into account so as to achieve a good temperature performance and the integrated opto-mechanical-thermal analysis should be conducted. The method and flow chart of integrated opto-mechanical-thermal analysis were discussed. An infrared lens with a focal length of 200 mm was designed, which matched with cold shield and could operate at a wide temperature range. The finite element model of the infrared lens was established and the thermodynamic analysis was accomplished, each lens interval and surface figure changes were obtained by using processed analysis data. The interval changes, Zernike coefficients and refractive index at ambient temperature were substituted into optical design software, and the temperature effect on image quality was obtained. The analysis results show that the modulation transfer functions of infrared lens with 16 line pairs in all field of views are larger than 0.5 from -40℃ to +60℃. The design of infrared lens is easy to be implemented and meets the requirements.