TW250538B - Process of moving focus type profile measurement of an asphericcylindrical surface - Google Patents

Abstract

A process of performing profile measurement of an asphericcylindrical surface, which comprises using different spheres, which have their curvature radius equal to different curvature radius of measured asphericcylindrical surface, as the reference plane and using an interferometer to measure the aspheiccylindrical surface waves from the measured object, in which the process comprises the following steps: (1) moving the measured object along the optical axis of the interferometer and measuring the movement quantity; (2) recording the different interferograms measured by the interferometer during each time when the measured object is moved; (3) locating the sparsest point in each interferogram and calculating the position of this point in which this point is the tangential point of the asphericcylindrical surface which is to be measured to each reference sphere; (4) calculating the deviation of each reference sphere with the measured object from the movement quantity and the tangential position; (5) integrating the deviations of reference spheres with the measured object obtained from step (4) to obtain the geometry of the measured object.