基于中波红外320×240制冷型探测器设计了一套双视场红外光学系统，利用光学被动式补偿温度焦移，实现对系统的无热化设计。介绍光学系统结构参数的求解过程，用Zemax软件进行设计，并对该系统在不同温度下进行仿真以及像质评价。实验结果表明：光学系统采用二次成像结构，使用8片透镜在3.7 μm~4.8 μm波段实现了50 mm和200 mm两档变焦，满足100%冷阑匹配，在-20℃~60℃温度范围内，系统Nyquist频率处MTF值均大于0.5。

Based on a 320×240 middle-wave infrared cooled detector, a dual field of view infrared system was designed. Using focal shift of optical passive compensation temperature, athermalization design technology was realized. The computation process to obtain structural parameters of the optical system was introduced, and then optimization was applied by using Zemax software. The optical simulation and image evaluation were carried out. The experimental results indicate that the system realize the zoom of 50 mm and 200 mm at the band of 3.7μm ~4.8 μm by using eight lenses, and cold shield efficiency is 100%. During the temperature range of -20℃~60℃, value of the modulation transfer function is all above 0.5 at the Nyquist frequency.