The Design Of Common Aperture Multi-band Optical System

Most of modern electro-optical targeting systems(EOTS) are monochromatic or dual-color systems, which have problems of weak information and low precision. In order to improve the detection ability of optical system under complex environment, common aperture multi-band optical system is designed.The paper described the working principle and composition of electro-optical targeting system, introduced the athermalization theory of refrigerational optical systems and the narcissus phenomenon, finally concretely described the design process of common aperture multi-band optical system. The working waveband of the system covers visible,the medium-wave and long-wave (3～5um and8～12um). Multi-band clear imaging is achieved with dispersive RC system, focal length of visible system is700mm, F#is3.5, and the full field of view is1°; focal length of infrared system is400mm, F#is2, and the full field of view is2°. In order to suppress the medium-wave thermal radiation stray light, the second imaging MWIR system is achieved and the narcissus phenomenon is analyzed. And it achieved the passive optical athermalization. The results indicated that the image quality is excellent under-40℃～+60℃, which can meet the using requirements of electro-optical targeting system.