中波红外光学系统无热化设计

介绍了无热化在红外光学系统中的作用和意义,分析了温度对光学参量的影响,探讨了无热化设计方法及光学被动式无热化基本原理.设计了一种用于320×256制冷型探测器光学被动式无热化中波红外光学系统,镜筒材料采用钛合金,光学材料为硅、锗和硒化锌组合消热差.该系统在-50~70℃温度范围内,最大离焦量小于1倍焦深,空间分辨率17 lp/mm处,光学调制传递函数(MTF)值大于0.7,比较接近衍射极限,探测器单像元内能量集中度大于84%.分析结果表明:该系统具有良好的成像质量和无热效果.

Athermal Design of a MWIR Optical System

The function and meaning of athermalization in infrared optical system was introduced. The influence of temperature on the optical parameters was analyzed. The athermal design methods and the principle of optical passive thermalisation were discussed. A midwave infrared optical system for 320×256 cooled detector was designed, in which the optical passive athermalisation was applied using optical material Si Ge and ZnSe with mechanical material titanium alloy in the optical system. The MTF is greater than 0.7, which close to diffraction limit in the spatial frequency 17 lp/mm, and more than 84% of the diffraction energy was focused in single pixel within －50～70℃. Those results show that the optical system has good image quality and athermal effect.