Patent ID: 6226092
Filing Date: 2001-05-01
Classification: G01B

Abstract:
A full-field geometrically desensitized interferometer for measuring the profile of an object surface, said interferometer comprising:means for generating first and second beams of radiation that have predetermined finite cross-sectional dimensions and travel along different paths;a first group of nondiffractive optical elements positioned along said paths for receiving said first and second beams of radiation and directing them at said object so that they are incident to said object surface at essentially the same location and area but from different angles of incidence, said incident beams reflecting from said object surface so that, upon reflection, they travel along different paths of propagation as separate reflected beams;a beam combiner located downstream of said reflected beams;a second group of nondiffractive optical elements for receiving said reflected beams and directing them at said beam combiner such that said reflected beams are combined into a single beam containing information about the profile of the object surface;a photodetector located downstream of said beam combiner; andimaging optics for receiving said single combined beam and forming an interference pattern on said photodetector, said second group of nondiffractive optical elements, said beam combiner, and said imaging optics being arranged such that radiation reflected from each object point contained in each of said reflected beams is uniquely mapped to a corresponding point on said detector.