机械补偿式红外温度自适应光机系统的设计

总结了红外温度自适应光学系统的实现方式,理论分析了机械补偿法的设计过程,研制了一种机械补偿式红外温度自适应光机系统。其光学指标焦距f=50 mm,相对孔径1/1.2,适配长波非制冷红外焦平面探测器,其像素为640×480,像元大小17 m,工作温度:―40℃～+80℃。设计结果表明,各个温度参考点各个参考视场的弥散斑半径均小于系统艾里斑,并且像面照度均匀。在空间频率20 lp/mm处,光学系统的调制传递函数接近衍射极限。利用机械补偿方式实现了系统各项技术指标。

Design of a Mechanical Passive Athermal Infrared Lens

This paper summarized the forms of designing temperature adapting IR system. The method of thermal compensation in mechanical passive way was analyzed. After that, an athermal IR system was made by using this method, whose focal length was 50mm, relative aperture was 1/1.2. This system was compatible with uncooled focal plane array which has a format of 640×480 and the pixel pitch of 17μm. It can adapt within the temperature range of－40℃~＋80℃. This system had extraordinary properties, for its RMS diameters in all reference field of each temperature were smaller than this system’s Airy disc; and the illumination had great uniformity. The MTF was near to diffractive limitation at the spatial frequency of 20lp/mm. By using mechanical passive thermal compensation technique, the performance of the system reached the targets required.