针对微光与红外图像融合手持观察镜展开论述。首先对比分离窗口布局与共用窗口布局的优劣，针对本文所设计的手持观察镜，选择共用窗口布局；其次分析折反射系统的特点，选择折反射与透射组合的图像融合光学型式；第三依据相应指标，对图像融合各个子系统开展光学设计；最后分析图像融合系统所成图像，得出此融合系统成像质量好，分辨率高，实现了图像融合的目的。

The paper discusses low-light-level and infrared image fusion hand-held viewer. Firstly, it makes a contrast with advantages and disadvantages between separable window layout and common window layout, and chooses common window layout for the hand-held viewer design. Secondly, it analyzes features of catadioptric system and chooses the image fusion optical type combined by reflection and transmission. Thirdly, based on the relevant indexes, it develops optical design for image fusion’s subsystems. Finally, through analysis of the image from image fusion system, it draws a conclusion that the fusion system has good imaging quality and high resolution ratio, achieving image fusion.