无热化双谱段复合成像光学系统

Design of athermalizing dual-band compound optical system

针对机载小型轻质和宽温度场的使用需求，基于光学被动消热差理论，设计了共孔径共视场分光路可见光和红外双波段无热化成像光学系统。两个谱段共用卡塞格林主光学系统，采用分色片实现双谱段分光。分光后两个谱段采用相互独立的中继透镜组。红外波段通过二次成像，实现双波段冷光阑100％匹配。通过共视场设计提高不同探测波段目标的信息一致性。可见光和红外谱段焦距分别为1750mm和1000mm，工作谱段为0．45～0．9μm、3～5μm，入瞳孔径为250mm，视场角1．1°，光学系统各谱段耐奎斯特频率处调制传递函数接近衍射极限，在宽温度场范围内像质稳定，完全能够满足实际使用需求。

According to the requirements of miniaturization and light weight for airborne optical systems, a visible and MIR dual-band compound athermal optical system with common aperture is designed based on the optical passive athermallization. The two channels of visible and MIR share Cassegrain optics, after which dichroic lens and independent relay lens are adopted. Secondary imaging technology is used for MIR channel, by which one hundred percent cold stop efficiency is realized. Enhanced target information consistency of different bands is achieved by common field design. The focal-length of visible and MIR channels are 1750mm and 1000mm respectively. The wavelength are 0. 45-0. 9μm, 3- 5μm. The diameter of the entrance pupil of the two channels is 250mm. The modulation transfer function of each band at Nyquist frequency is near the diffractive limit. Athermalization is achieved in working temperature scope, which satisfies the needs of practical applications.