Patent ID: 6721056
Filing Date: 2004-04-13
Classification: G01B

Abstract:
An apparatus for measuring the surface shape of a surface to be measured of an optical system comprising:a stage holding the optical system thereon; an irradiating optical system for sequentially applying a coherent light beam to a plurality of measuring diameter positions of the surface to be measured of the optical system while the optical system and the coherent light beam are relatively rotated; means for detecting the relative rotation azimuth of the optical system and the coherent light beam; a light receiving element for detecting light of the coherent light beam reflected from the surface to be measured; and a calculating system for effecting measurement of the surface shape of the surface to be measured on the basis of the result of the detection of the coherent light beam at each of the plurality of measuring diameter positions of the surface to be measured and the result of the detection by said means for detecting the relative rotation azimuth, wherein said irradiating optical system condenses the coherent light beam at one of (i) the center of the curvature of the surface to be measured, and (ii) the apparent center of the curvature of the surface to be measured.