设计了一款长焦距大变倍比轴向变倍四视场中波红外光学系统.该光学系统由前固定组、变倍调焦组、中间补偿组、后固定组、反射镜一、反射镜二、中继组组成.光学系统采用光学补偿叠加机械补偿方式克服单一光学补偿或机械补偿变焦方式无法同时满足光学系统长焦距、大变倍比、光学系统小型化、光学系统宽温度范围(-40℃～70℃)温度补偿等问题, 实现了兼具长焦距和大变倍比的轴向变倍四视场中波红外光学系统.设计结果表明该光学系统像质良好, 满足热象仪整机使用要求.

In this research, we designed an MWIR optical system, which is equipped with long focal length, large zoom ratio, axis-zoom and four fields of view. The optical system is composed of seven components, including a front fixing group, a zoom focus group, an intermediate compensation group, a rear fixing group, a first mirror, a second mirror and a relay group. The optical system uses optically compensation superposition mechanical compensation method to improve the major flaws existing in previous similar optical system, that is, the single optically compensation or mechanically compensated zoom optical system cannot meet the followed requirements at the same time. The requirements includes long focal length, large zoom ratio, compact optical system, and temperature compensation for optical system under wide temperature range (-40 to 70℃), etc. The improvement achieved long focal length, large zoom ratio, axis-zoom and four fields of view. The improved design results show that the image quality of the optical system is perfect, and it can meet the requirements of the thermal imager.