Assembly and integration testing method for cryogenic optics infrared camera

Cryogenic optical technology aimed at reducing background radiation is the main way to improve the infrared detection capability of space cameras. This paper elaborates on the method of assembly and testing for a cryogenic optics infrared camera with full optical path cooling from the perspective of engineering applications, providing a certain reference for the development of other cryogenic optical cameras. An elastic support framing method for ZnSe lens is proposed, by matching the stiffness of the elastic support structure, and using the rod tooling to accurately and quantitatively compress the spring, the lens meets the requirements of the mechanical environment. The RMS change of the surface accuracy from room temperature to 90K is less than 0.02λ, and the effectiveness of the framing method is verified by experiments. The assembly method of thermal conductive components was optimized. By comparing the working temperature and contact heat transfer coefficient of different interface thermal conductive fillers, indium foil was selected as the optimal interface material. Through simulation analysis of interface contact pressure, the optimal mechanical connection method was formulated. The installation method of multilayer insulation are improved. By staggered lapping, reserving low temperature shrinkage allowance, increasing the multi-layer interval, the thermal insulation effect of MLI has been significantly improved. By using the method of presetting the focal plane at room temperature and conducting over focusing tests under low temperature conditions, the optimal focal plane position is determined to ensure that the camera MTF and energy concentration meet the requirements.