Patent ID: 6597442
Filing Date: 2003-07-22
Classification: G01M

Abstract:
An aberration measuring apparatus for detecting an aberration of a lens for converging an incident light beam passing therethrough, said apparatus comprising:a laser for emitting a light beam of a single wavelength; an optical system for dividing the light beam into first and second light beams, and for guiding said first light beam to said lens; a reflector having a concave mirror surface consisting of a portion of a sphere having a center of curvature, and reflecting said first light beam incident thereon after said first light beam passing through said lens is converged to a converging point different than the center of curvature; a detector for detecting an interference pattern created when said second light beam and said first light beam reflected by said reflector interfere with each other; a driving unit for moving said reflector with respect to an optical axis of said optical system, thereby displacing the center of curvature from the converging point so as to change said interference pattern to an interference fringe pattern comprising a plurality of circles arranged approximately concentrically; and an analyzer for analyzing the aberration of said lens and determining the aberration of said lens based on an analysis of a distribution of said plurality of circles.