由于我国幅员辽阔，不同地域的环境温度差别巨大。为满足建筑工程安全监控用红外热像仪的环境适应性要求，采用了折射/衍射混合光学被动无热化设计方式。通过对不同红外光学材料透镜的光焦度进行合理分配，设计了一种能够在-55～70 ℃范围内工作、视场为24.1°×19.4°的小型化非制冷红外成像光学系统。该系统的工作波段为8~12 μm，F数为1.0。设计结果表明，系统结构简单、体积小且成像良好，在空间频率42 1p/mm处的光学调制传递函数 (Modulation Transfer Function，MTF)值大于0.3，可以满足应用需求。

Due to the vast territory of China, the environmental temperatures in different regions vary greatly. In order to meet the environmental adaptability requirements of the infrared thermal imager for safety monitoring of building engineering, the passive uncooled design mode of refraction and diffraction mixed optics is adopted. Through the reasonable distribution of optical focal degree of the lens with different materials, a miniaturized uncooled infrared imaging optical system is designed, which can work in the range of -55 ~ 70 ℃ and has a field-of-view of 24.1°×19.4°. The operating wavelength range is 8~12μm, and F number is 1.0.The design results show that the system has simple structure, small volume and good imaging quality. The value of optical modulation transfer function (MTF) at the spatial frequency 42 1p/mm is greater than 0.3, which can meet the application requirements.