Mounting Technology Of Large Mirror In Collimator Based On FEM

Along with the developing of science and technology, especially the developingof space optics, the long-focal length and high-resolution optical systems are needed.Collimator is an instrument which provided parallel beam of light. It is the benchmarkof testing large-aperture and long-focal length optical system. In the dissertation, theprimary mirror is the key part of the collimator designing. The surface figure of theprimary mirror affects the imaging quality directly.The development of the primary mirror's mounting method was summarized.The development of the finite element method and its application in optomechanicaldesign were summed up.Zernike polynomials and Homogeneous coordinate transformation methods wereintroduced, as two useful data processing methods. By comparing the two methods, aconclusion that Homogeneous coordinate transformation method would be moreappropriate in this research was drawn.During the research of backside bonding mounting, the feasibility of the newmethod bonding with elastomeric adhesive was researched detailedly. Elastomericadhesive RTV was chosen and the adhesive thickness was calculated (0.4mm). Thenthe finite element model of the primary mirror was built. Several models of the threecases such as 3/4/6 points mounting were analyzed by the finite element method. Therelation between surface figure and the bonding area, the mounting radius, or theangle from one mounting point to Y-axis was analyzed. A conclusion that 6 pointsmounting would be chosen in this thesis was drawn.The structure of the 6 points backside mounting was draft. Firstly the 6 pointswere mounted to 3 joints. Then 3 joints were fixed to the shelf.