中波红外连续变焦光学系统

针对制冷式320×240凝视焦平面阵列探测器,设计了一个中波红外连续变焦光学系统。该系统由变焦物镜系统和二次成像系统构成,包括7片透镜,引入一个非球面,并采用两个反射镜折叠光路。利用变焦系统原理和光学设计软件给出了系统的光学参数和外形结构图,并对其像质和冷反射进行了系统分析。该系统可以实现50~500 mm的连续变焦,工作波段为3.7~4.8 μm,满足100％冷光阑效率。结构紧凑,像质较好,变焦行程短,变焦轨迹平滑。

Middle infrared continuous zoom optical system

For cool 320×240 detector with staring focal plane array, a middle infrared continuous zoom a optical system was presented. The optical system using optical configuration of reflect mirror fold is composed of a zoom object lens system and a secondary imaging system, including seven lenses and two reflectors. Based on the practical requirement and feature parameters of detector, the optical design parameters were given. Using zoom system principle and optical design software, the schematic diagram, modulation transfer function (MTF) curve, spot diagram, and Root Mean Square (RMS) value of the spot diameter were investigated. Finally, the cold reflection ray-tracing of short EFL end was studied and the correlative schematic diagram was also given. The results indicate that the optical system with 3.7~4.8 μm spectral region can realize 50~500 mm continuous zoom and satisfy 100% cold shield efficiency. It has the advantages of simple structure, high image quality, short zoom path and smooth zoom locus. And moreover, only one aspheric surface is adopted in the system, so the system is in a low price and easy to machine and adjust.