为了解决多光谱成像系统的轻小型设计难点，采用单探测器多谱段成像方案进行了同时刻四谱段成像系统的光学系统设计。分光原理为，在物镜组前方设置四片楔形滤光棱镜，并在棱镜表面镀上透过不同谱段的透过薄膜；物体辐射经过棱镜后不同谱段的辐射发生不同方向的偏折，即在焦平面的不同位置形成了分离的光谱像。设计过程中，采用渐晕的方法解决谱段间的重叠问题。设计得到的光学系统波段数为4，工作波长为8.20~8.60 μm、9.40~9.80 μm、10.60~11.20 μm及11.20~12.20 μm，焦距为55 mm，全孔径为80 mm，光学系统的弥散圆直径小于40 μm，并分析了系统的像差特性。分析结果表明，该系统具有良好的成像质量，满足多谱段成像要求。

The design of four spectrum imaging of a single sensor spectro-imaging system was presented. The prism was placed before lens set, departure at different direction of the objective radiation across prism, the separate spectro-image was formed at different place of focal plane. The F number of the spectro-imaging system whose working wavebands are 8.2-8.6 μm, 9.4-9.8 μm, 10.6-11.2 μm and 11.2-12.2 μm is 4, the focal length is 55 cm and the aperture diameter is 50 mm. The spot diagram diameter is less than 40 μm. Vignetting was introduced to solve the superimposition between different spectrum. The aberration characteristic and the blur circle diameter distribution of the system was analyzed. The analysis results showed that the system had a good image quality and met with spectro-imaging requirements.