20×长波红外连续变焦光学系统设计

Design of LWIR Zoom Optical System with 20:1 Zoom Range

针对384×288长波量子阱焦平面探测器,设计了一个变倍比为20×的长波连续变焦光学系统,其工作波长范围为8～9 m,F数为3,可实现18.5～367mm的连续变焦。该系统由机械补偿变焦物镜和二次成像系统组成,包括6片透镜和2片反射镜,具有大变倍比、高分辨率、小体积、高像质等优点,并用ZEMAX光学设计软件进行了仿真计算和像质评价,在奈奎斯特频率20 lp/mm处,系统全焦距范围内的MTF接近衍射极限。

An infrared zoom optical system with a zoom range of 20：1 is designed based on long-wave 384 × 288 QWIP detector. The operating wavelength range is from 8 to 9um, the F number is 3, and the focal length is continuously changeable form 18.5 to 367 mrn. The system consists of a mechanically compensated zoom object and a secondary imaging system, including 6 lenses and 2 reflectors, and has the advantages of large zoom ratio, high resolution, small size and excellent image quality. The zoom optical system image quality is evaluated with ZEMAX optical design software, and the results show that the MTF in the whole focal approaches the diffractive limit at the Nyquist frequency of 20 lp/mm.