消热差大相对孔径中波红外望远物镜的研制

Development of an athermalization midwave infrared telescopic-objective with fast speed

为满足低成本空间热成像系统重量轻、适应环境温度范围宽的要求,研制了消热差的大相对孔径中波红外望远物镜,其焦距为100mm,F数为1,全视场角为5°。物镜设计采用了匹兹伐结构型式,仅由两块硅(Si)透镜和一块锗(Ge)的折/衍混合透镜组成,能够实现-20～+60℃环境温度变化范围内光学被动消热差。对实际加工的红外物镜进行了性能测试,在一定温度变化范围内,特征频率处的MTF的数值均大于0.75,其变化值小于0.05,表明研制的物镜能够保持稳定的良好成像质量,具有好的消热差性能。由所研制的物镜和非制冷探测器构成的成像系统具有相对孔径大、适用环境温度范围宽、结构紧凑、成像性能高的优点,适合于作为低成本微小卫星的有效载荷。

In order to meet the requirement of light weight, good adaptability to wide environment temperature change for low cost space thermal imaging systems, an athermalization midwave infrared objective with fast speed is de veloped. The focal length is 100mm, F-number is 1, and full field of view is 5°. The designed optical system adopts Petzval structure, which includes only two pieces of Si refractive lens and a piece of Ge hybrid lens. Passive optical athermalization is applied, so the system can work over wide temperature range from --20～ ＋60℃. The fabrication and alignment of the optical system are completed, MTF is tested. The results show that the system can keep stable and good im age quality over certain temperature range. The developed objective has large relative aperture, good adaptability to envi- ronment temperature, compact structure and high quality image. The imager composed of the above objective and certain type of uncooled detector is compatible for payload of micro-satellite.