Design and analysis of adaptive flexible support for cold optical lens

With the increasing demand of infrared detection, the infrared cold optical technology has developed rapidly in recent decades. The low temperature deformation of infrared optical elements is one of the key factors restricting the development of infrared cold optical technology. The processing and assembly of optical subassemblies and support structures are carried out at room temperature and pressure, while the actual working environment of infrared system is relatively low temperature environment, which can vary by 200 degrees Kelvin or more. Therefore, the temperature adaptability of the support structure is strictly required. The optimal design flexible support of the 70mm diameter single crystal lens made by germanium was carried out to ensure that the component surface shape reached (1/6). and the natural frequency was above 200HZ at 100K low temperature in this paper. At the same time, the ISIGHT integrated optimization method was used to optimize the flexible support structure. The multi-objective integrated optimization of key dimensions of flexible support was completed, aiming at maximizing the fundamental frequency of the system and minimizing the lens surface shape errors. Finally, the optimal size was selected to complete the flexible structure design. In this paper, an adaptive flexible support structure for cold optical lens with three layers of stress release was designed by multi-objective integrated optimization method. Meanwhile, its performance was verified by low temperature tests. The results verified the reliability and the feasibility of the structure design and analysis.