高分辨率红外变焦光学系统设计

Design of Infrared Continuous Zoom Optical System with High Resolution

针对1 024×768元长波非制冷式焦平面探测器的应用需求,设计了一款4×连续变焦高分辨率光学系统,并利用ZEMAX宏语言编写的宏程序,对该系统的变焦过程进行了分析。该系统采用机械补偿变焦方式,在6片锗单晶镜片上设计了3个非球面和1个衍射面,矫正了高级像差,实现了在25~100 mm范围内的平滑连续变焦,视场角可达32°×24.3°~8.2°×6.15°;从宏程序输出的变焦凸轮曲线、弥散斑变化曲线和视场畸变变化曲线上看,该系统在整个变焦过程中运动平滑、成像稳定、弥散斑和视场畸变变化均较小。综合而言,该系统具有结构紧凑、相对孔径大(F#/1~1.4)、视场畸变小、成像质量高、变焦凸轮机构加工难度小,具有较高的应用价值。

A 4×continuous zoom optical system with high resolution is designed for the application of the long wave uncooled focal plane array （FPA） detector with 1 024×768 pixels. The zoom process of the system is analyzed by using a macro program written by ZEMAX macro language. The mechanical compensation zoom mode is used in the system, and there are six pieces of germanium lenses with three aspheric and one diffractive surface. The high order aberrations is well corrected and the system can zoom smoothly and continuously in the focus length range of 25-100 mm with the viewing angle from 32°×24.3° to 8.2°×6.15°. From the zoom cam curve output from macro program, diffuse spot curve and field distortion curve, it can be seen that the system runs smoothly in the whole zoom process with a high-quality stable image, the various of the diffuse spot and the field distortion is small. In conclusion, the system has the advantages of compact structure, large relative aperture （F#1-1.4）, small field distortion, high image quality, and easy to manufacture the zoom cam mechanism, and has high application value.