Study on mechanical structures for large flat applied to large-aperture interferometer

Abstract

The deformation of the φ600mm reference mirror under gravity cannot be ignored when measuring optical components with a φ600mm interferometer. Therefore, it is necessary to choose a reasonable support and rotation mechanism to adjust the reference mirror of the interferometer in order to meet the accuracy requirements. In this paper, two mechanical structures for supporting and rotating the φ600mm reference mirror are analyzed. One is using the roller slings to provide tension, and the conveyor belt drives the reference mirror to rotate by friction; while the other one is using glue to connect the silica gel and the edge of the reference mirror where silica gel is fixed on the metal frame. The rotation of the reference mirror can be realized by manually rotating the frame. In order to analyze the influence of the two mechanisms on the mirror under working conditions, a three-dimensional model of the φ600mm reference mirror with its supporting system was established using the finite element analysis software ABAQUS, and the contact conditions and boundary conditions were reasonably applied to the reference mirror. Reference mirror is analyzed in both statical and dynamical states. The changes of internal stress and surface shape are compared when the reference mirror is supported and rotated on both mechanisms. The advantages of different mechanisms are elaborated, and the parameters of mechanisms are optimized theoretically. Analysis results can provide a useful guide for the support of the reference mirror and the adjustment of the φ600mm large aperture interferometer.