Simulation and Experiment of A Large Aperture Flat Mirror Support Structure
In order to improve the measurement accuracy of the surface profile of a 600 mm large diameter vertical plane mirror rotated 90° along the optical axis,the finite element simulation analysis of the gravity deformation of the plane mirror with five different materials under the porous support structure was carried out,and the influence of the standing time after rotation on the surface profile accuracy was explored through the experimental measurement.The results show that the axial deformation of the plane mirror surface caused by gravity under the po-rous support structure is less than 14 nm,which meets the accuracy requirements.The planar mirror supported by the porous structure rotated 90°along the optical axis and reached a stable state after standing for 1 h.The PV and RMS values of the planar mirror supported by the porous structure were only 0.337 nm and 0.081 nm different from the planar mirror results after standing for 2 h.The influence of the standing time on the planar mirror results was explored.Then,it is found that the PV value of the surface profile of the plane mirror can be greatly reduced under the condition of removing at most 6％of the outer diameter,and the PV value can be reduced by more than 50 nm.A method is proposed to im-prove the profile accuracy of the large diameter plane mirror by setting the buffer of the supporting structure,which can effectively improve the profile accuracy of the large diameter plane mirror.
large aperture flat mirrorfinite element simulationinterferometric measurementrotation measurementexperimental verifica-tion
万方数据
维普
