设计了一种采用长波480×6阵列探测器的红外连续变焦光学系统.该系统利用机械补偿法变倍原理和非球面、衍射面进行像差平衡，工作波长范围为长波7.7～10.3 μm，F数为2.62，变倍比达到15∶1.通过对连续变焦光学系统的传递函数、畸变、衍射元件、变焦曲线等性能的综合分析与评价，结果表明在变焦范围内下各个视场均可获得较好的光学性能，光学系统光路总长480 mm、后截距为28 mm、传递函数大于0.3、畸变小于5%.

The design of an infrared zoom optical system based on 480×6 focal plane array detector was introduced. The zoom theory, diffractive theory and aspheric design method were used in the aberration balance. The operating wavelength region was 7.7 to 10.3 μm, F-number was 2.62, and zoom ratio was 15 to 1. The result indicates that the zoom optical system could obtain better optical performance in all zoom range, by the general analysis and evaluation of modulation transfer function, distortion curve, diffractive optical element, and zoom curve analysis. The overall length of optical system is 480 millimeter, back focal length is 28 millimeter, modulation transfer function is more than 0.3 and distortion is less than 5 percent.