光学被动消热差的长波红外双视场光学系统设计

Design of dual field-of-view optical system in long wave infrared with optical passive athermalization

依据光学被动消热差理论，利用硫系玻璃的热稳定性、长波红外透过特性等优点，对长波非制冷双视场光学系统进行了无热化研究，设计了一个大相对孔径、3倍变焦的双视场长波红外光学系统。其具体参数为：F/#为1，焦距为50/150 mm，总长240 mm ，采用640×480的焦平面探测器，像元大小为17μm×17μm，工作波段8~12μm，系统使用了三种长波红外材料：Ge、ZnS、IRG201。在-40~60℃下，其长短焦处像质均接近衍射极限。

Based on the theory of optical passive atherma lization and the research of athermalization for dual-field-view un-cooled LWIR optical system, a LWIR optical system with large relative aperture and 3x step zoom was designed using chalcogenide glasses which posses good thermal stability and unique LWIR optical properties. The specifications are as follows： F/# is 1, EFL is 50/150 mm, and total length is 240 mm. The 640í480 FPA detector was adopted whose pixel size is 17 μmí17 μm with working band from 8 to 12 μm. Three LWIR material was used in the system which were Ge, ZnS, IRG201. The image quality is diffraction limited from - 40 to 60℃ at both WFOV and NFOV.