Investigation of Surface Deformation under Clamping Force and Clamping Repeatability

Abstract

Geometrical deformation of lens surface caused by kinematic mount clamping force is analyzed with finite element method and lens surface displacements are extracted and fitted with Zernike polynomials. Analytical results show that Defocus、Pri Trefoil and Pri Hexafoil are the main aberrations under clamping force. During the process of optical testing, repeating assembly of the kinematic mount apparatus may influence the testing accuracy, so relations between assembly repeatability and surface deformation are also investigated. In order to evaluate the repeatability for assembling, variations of peak valley (PV) and root mean square (RMS) values changed with clamping force and clamping placement in circumferential and radial direction are also shown in this paper. The results indicate that PV and RMS values do not obviously change as clamping force and clamping placement change, which means that slight assembly errors of the kinematic mount apparatus are allowed.