Transformation of the results of the finite-element analysis of optical-surface displacements for use in optical-analysis packages

Abstract

This paper discusses questions of how to increase the accuracy of an approximation by Zernike polynomials of the displacements of the points of optical surfaces (OSs) in the direction of the optical axis, associated with the discrimination of displacements of the surface as a rigid whole. It is shown that, when going from displacements of the nodal points of an OS obtained by the finiteelement method to their approximation by Zernike polynomials, it is expedient to discriminate beforehand that part of the displacements associated with the components of the displacement of the surface as a rigid whole in a direction perpendicular to the optical axis, and, in the case of nonaxisymmetric surfaces, also in the direction of rotation around the optical axis. Examples are given of the implementation of the proposed procedure.