Thermal optical property analysis of three mirrors aberration optical system

Module transform function (MTF) of three mirrors aberration (TMA) optical system would be changed when the structure deformation is occurred. The thermal optical property of frame is analyzed. Firstly, the finite element analysis (FEA) models of frame and three reflector mirrors are set up by FEM analysis software, and temperature distribution calculation is completed by FEM analysis software. It includes x axial, y axial and z axial temperature gradients. Secondly, the thermal elasticity deformations of reflector mirror surfaces made by frame deformation are computed in elastic force methods .The deformation of reflector mirror surfaces are expressed in Zernike polynomial. Finally, the results of reflector mirrors deformation influencing on optical system are computed by optical design software. The optical system image quality decided by surface deformation is analyzed. The results show that the x axial temperature gradient causes the MTF of optical system changed furthest, the y axial temperature gradient causes the minor MTF change, and the z axial temperature gradient caused the least change of MTF. Requirement of the x axial temperature difference is 4°, the y axial temperature difference is 6°, the z axial temperature difference is 6°. The simple thermal control is proposed. The research jobs could give some guidance and reference for the thermal design for TMA optical system.