针对制冷式640×512元凝视焦平面阵列探测器，设计了结构紧凑的高性能机械补偿30倍连续变焦光学系统.该系统采用新颖的三组元变倍形式和三次成像方法设计.工作波段为3.7 ~ 4.8 μm，F/# =4，变焦范围750 ~25 mm.首先利用光学设计软件给出了系统的光学外形结构图; 然后，进行了像质评价分析，变焦曲线分析，温度环境适应性分析和冷反射分析; 最后，介绍了该系统应用微扫描成像技术提高分辨率的方法.结果表明，该光学系统在空间频率30 lp/mm处的光学传递函数 ( MTF) 值均接近衍射极限, 弥散斑直径的均方根 ( RMS) 值均小于15 μm.变焦曲线平滑，且移动组最大行程小于71 mm.移动组透镜的轴向移动可完成系统调焦及温度补偿.光学系统满足100 %冷光阑效率，在-40 ~60 ℃温度范围内均有良好的像质.同时，满足新一代机载前视红外( FLIR)系统的要求.

A compact, high-performance optical system with mechanical compensation was designed with a 30 times continuous zoom for a 640×512-element cooled staring focal plane array detector. The system was designed using the novel three-group zoom in the form and thrice imaging methods. The system operates in the waveband of 3.7~4.8 μm. F/#=4. The zoom ranges from 750 mm to 25 mm. First, gives the schematic drawing of the optical system was obtained with the optical design software. Then, the optical design software has the analysis of the image quality evaluation, the zoom curve analysis, the temperature environment adaptability analysis, and the Narcissus were analyzed with the same software. Finally, the paper proposed a way to improves the resolution of the system using micro-scan imaging technology. The results show that the modulation transfer function ( MTF) of the optical system is close to the diffraction limit at a spatial frequency of 30 lp/mm and the root-mean-square value of its diffusion spot diameter is less than 15 μm. Zoom curve is smooth and the maximum displacement of the move group is less than 71 mm. The focusing and the temperature compensating of the system were achieved via the axially moving of the mobile group lens. The optical system satisfies l00% cold-shield efficiency and has good image quality in the temperature range of -40~ 60 ℃. Meanwhile the optical system meets the requirements of the new generation of airborne forward looking infrared ( FLIR) system.