Design and analysis of window structure for projection objective

The design requirement for the surface accuracy of optical components in the projection objective is to reach the nanometer level, which poses extremely high requirements for the surface accuracy of integrated optical components. In the projection objective system, the window lens group is a key component to ensure the normal operation of the optical mechanical system. It not only protects the internal environment of the objective but also participates in the system imaging. A flexible support structure for an integrated three-point positioning window lens is designed in the projection objective. The natural frequency of the overall structure and the influence of the supporting structure on the surface shape of the lens are analyzed. In optical system error analysis, the accuracy of surface shape prediction is achieved by analyzing the similarity between the upper and lower parts of the window lens. A multi-objective optimization algorithm has been used to improve the accuracy of lens surface shape and the stiffness of the lens group. Isodomain analysis is conducted on the support surface shapes of window lenses of different sizes, which can be served as theoretical basis and empirical data for the design of similar structures. The method proposed in this paper for designing, optimizing, and analyzing the support structure of window lens can provide a theoretical basis for the development of window lens support structures in projection objective.