Design and analysis for the flexible support structure of high precision lens assembly

In order to achieve support and positioning of lens assembly which have large aperture and high precision in the on-orbit assembly space telescope validation prototype, A novel lens support structure with multi-point flexible units and four point length-adjustable radial holding is proposed. Then, the structure optimization is finished based on gravity deformation and thermal deformation. Finally, the influence of gravity and thermal load on the lens surface figure under this support structure is given by finite element analysis. The results show that: the largest first lens in the lens assembly is taken as an example, lens surface figure (RMS) of the upper surface causing by gravity and +2°C thermal load is 3.09 nm, while the lower surface is 3.03 nm, and lens surface figure RMS of the upper surface causing by gravity and -2° C thermal load is 3.43 nm, while the lower surface is 3.39 nm. The results and practice indicate that the multi-point flexible support structure can effectively reduce the influence on lens surface figure by gravity and thermal load, and can be satisfied with the lens surface figure accuracy (RMS < 4 nm).