Patent ID: 6552807
Filing Date: 2003-04-22
Classification: G01B

Abstract:
An apparatus for surface shape measurement using an interferometer, comprising:a phase shift interferometer for imaging at least three interference fringe images each generated by emitting a coherent light to an object having a test surface and to a reference having a reference surface so that a test light reflected from said test surface interferes with a reference light reflected from said reference surface while varying a phase difference between said test light and said reference light from image to image; a surface shape analyzer for analyzing said at least three interference fringe images taken by said phase shift interferometer to obtain surface shape information of said test surface; a typical plane computer for computing a typical plane of said test surface on the basis of said surface shape information obtained from said surface shape analyzer; an oblique angle computer for computing an oblique angle of said typical plane computed by said typical plane computer to said reference surface; and an attitude adjusting mechanism for automatically adjusting the attitude of said test surface relative to said reference surface on the basis of said oblique angle computed by said oblique angle computer.