大相对孔径紧凑型无热化红外光学系统设计

根据目前搜索和跟踪系统要求其红外成像光学系统具有高成像质量、超轻小型化和高温度适应性的特点。采用折反射式光学系统结构形式,基于J-T制冷型320×320凝视焦平面阵列探测器,设计了一种大相对孔径紧凑型无热化红外光学系统,光学系统远摄比达到0.6。采用光学被动消热差方法进行设计,使该系统在-40℃～60℃温度范围内实现了无热化。同时采用杂散辐射分析软件对系统进行杂散辐射分析,提出合理杂辐射抑制方案,给出了完整的光学系统设计。结果表明,光学系统在不同温度环境下所有视场的调制传递函数(MTF)(17lp/mm)均接近衍射极限,80%的能量集中在1个像元内,且具有结构紧凑、体积小等优点,可满足搜索和跟踪红外光学系统的使用要求。

Design of a Low F-number Compact Athermalizing Infrared Optical System

According to the requirements of good image quality, miniaturized dimension and high-temperature environmental adaptability in the applications of infrared search and track systems presently, a compact infrared catadioptric system structure is used, which base on the J-T cooler staring high-sensitivity focal plane array infrared detector comprised of 320×320 elements, to design a low F-number and compact athermalizing infrared system optical system. The ratio of total length and focal length is 0.6. A passive optical athermalization design is used for infrared optical systems, which makes the system athermalize in the temperature range of -40 ℃～60 ℃. The stray radiation in the system is also analyzed and a scheme to suppress the stray radiation is given. The results show that the modulation transfer function (MTF) (17 lp/mm) of optical system in all field of view approaches the diffraction limit at different temperature, and 80% energy concentrates in 1 pixel. The optical system has many advantages, such as compact structure, small volume and so on . It can meet requirement of imaging infrared search and track.