红外光学系统在一定温度条件下会由于温度变化导致系统成像质量变差.利用光学材料热特性之间存在的差异,提出一种光学被动式无热化设计方法,分析了透镜组的消像差方程组并进行求解,讨论了不同透镜材料消热差和消色差的实现过程,利用不同材料合理匹配与合理分配光焦度实现热补偿.针对相同技术指标,设计了两个红外双波段光学系统并对两种系统性能进行比较,结果表明,采用热补偿措施的红外系统在-40～+60℃温度范围内弥散圆尺寸变化不大,焦距变化量小于系统最小焦深,成像质量接近衍射极限,不同温度下系统焦距的变化不影响成像质量和性能.%Temperature change could cause the degradation of imaging quality of infrared optical system under certain temperature. A method for passive optical athermalization was proposed by using the difference of heat characteristics of optical materials. Aberration correction equation of multilenses was analyzed, and implementation process of athermalization and achromatic of different lens material were discussed. At the same time, thermal compensation was achieved by means of the appropriate focal power arrangement and proper match of optical material. Two infrared dual-band optical systems were designed for same technical specifications, and their performance were compared with each other. The result indicates that; 1 ) the dispersive spot size changes slightly while the temperatures changed from -40 ℃ to +60 ℃ when the systemadopting thermal compensation；2) the change of focal length is less than the minimum focal depth of system, and image quality of the system is near diffraction limit;and 3) the variation of the optical system focal length has no effect on the system performance.
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