折衍混合长波红外摄远物镜设计

The Design of a Refractive-diffractive Hybrid Longwave Infrared Telephoto Lens

红外光学系统具有可全天候工作、远距离观察等优势,在军事及民用领域均得到广泛应用。但由于温度对红外系统影响较大,所以需要对其进行消热差设计。依据消热差及色差原理选择适合的透镜材料,利用衍射元件的消热差和色差的特性,设计了波段为8~12μm,全视场为2ω=6°,焦距为f=100mm,F数为2,温度补偿范围-40℃~60℃的长波红外折衍混合摄远物镜。使用保罗I棱镜来折叠光路,使系统结构紧凑,摄远比达到了0.8。该系统在-40℃~60℃范围内,调制传递函数（MTF）优于0.5,接近衍射极限,成像质量良好。

Infrared optical system has many advantages such as working all day,remote observation and so on,so it is widely used in military and civilian fields. However, due to the greater impact of temperature on the infrared system, so it needs to be designed with athermalized methods. Based on the principle of athermalized and chromatic aberration, the appropriate lens material is selected, the long-wave infrared refractive -diffractive hybrid telephoto lens is designed by using the athermalized and chromatic characteristic of diffractive element, which working band is 8~12μm, the whole field of view 2ωis 6°,the focal length f ＇is100mm,F number is 2 under temperature compensation range -40℃~60℃. Paul I prism is used to fold optical path,so the system is compacted and the telephoto ratio is 0.8. Its modula-tion transfer function is above 0.5 in the temperature range from -40℃~60℃,The system requires good image quality.