基于硫系玻璃的紧凑式大相对孔径长波红外光学系统无热化设计

硫系玻璃作为光学晶体的替代材料得到广泛关注，其具有光谱透过率高、热稳定性好、适合模压成型、价格便宜等特点。基于硫系玻璃的温度特性以及光学被动消热差理论，设计了工作波段为8 μm～12 μm、F#为1、视场角为38°、系统总长为16.7 mm红外消热差光学系统。系统采用三分离式结构，使用IRG202和IRG206两种硫系玻璃材料，仅引入2个偶次非球面，未使用衍射面，具有结构紧凑、成本低、光通量高等优点。系统适配像元数为384×288 的非制冷型红外面阵探测器，像元大小为17 μm。设计的镜头在?40 ℃～60 ℃温度范围内，各视场调制传递函数在奈奎斯特频率处均大于0.4，光学系统成像性能稳定。该系统可广泛应用于车载夜视和安防监控领域中。

Compact large relative aperture long wavelength infrared athermalization optical system with chalcogenide glasses

As the substitute material of optical crystal, the characteristics of chalcogenide glass with high spectral transmittance, high thermostability, moldable property and low price received extensive attention. An infrared athermalization optical system was designed based on temperature characteristics of chalcogenide glass and theory of optical passive athermalization. The working band was from 8 μm to 12 μm, the F-number was 1, the field angle was 38°, and the overall length was 16.7 mm. The system was composed of three lenses, which used two chalcogenide glasses materials, IRG202 and IRG206 respectively, only introduced two even aspheric surfaces, and no diffraction surface was used. The system had advantages of compact structure, low cost, and high luminous flux, which was compatible with uncooled infrared area-array detector that had pixel elements of 384×288, and pixel size of 17 μm. From ?40 ℃ to 60 ℃, the MTF of designed lens of each field of view is greater than 0.4 at the nyquist frequency, and the imaging performance of optical system is stable. The system can be widely used in the field of vehicle night vision and security monitoring.