为了提高双波段光学系统成像性能, 结合可见光和中波红外的特点, 设计了无光路补偿的折/衍射双波段共光路齐焦光学系统。对系统的4片透镜波段间消色差以及焦距补偿表达式进行了推导, 采用4片透镜并引入二元衍射面, 通过合理匹配光学系统光焦度, 实现了系统共用一组光路, 在可见光和中波红外两个波段的焦距一致, 提高了双波段观测目标信息的一致性。设计的双波段共口径/共光路成像光学系统的工作波长为0.38~0.76 ?滋m, 3~5 ?滋m, 系统的焦距为90 mm, 视场角为0.5°, F数为3, 在-40~+60 ℃的温度范围内采用光学被动式进行消热差设计。设计结果表明: 系统结构简单, 体积小, 成像质量接近衍射极限。

In order to improve the imaging performance of dual-band optical system, considering the characteristics of visible light and MWIR, diffractive-refractive dual-band co-path and parfocal without compensation optical path optical system was designed. The four lens achromatic and focal length compensation expression between wave band were derived. The system used four lenses and introduces binary diffraction surface by properly matching the optical system power to achieve common optical path. The focal lengths were consistent between the visible and infrared, which improves consistency of dual-band target information. The optical system operating wavelength is 0.38-0.76 ?滋m and 3-5 ?滋m, the focal length of the whole optical system is 90 mm, the field of view is 0.5° and the F number is 3, respectively. The dual-band athermal optical system with the temperature of -40-+60 ℃ was designed with the use of optical passive. The results show that the designed system structure is simple and the size is small, has an excellent in overall image quality.