Tropel Corporation

Qed Technologies International, Inc.

Jon F Fleig

Mark Joseph Tronolone

Chunsheng J Huang

John H Bruning

Gary M Devries

An object fringe pattern is distinguished from other fringe patterns in an interferogram produced by an interferometer using a pair of diffraction gratings for separating and recombining test and reference beams. The object on which a test beam is grazingly incident is moved in X and Y directions in a plane perpendicular to an optical axis of the interferometer to change the brightness regions of the object fringe pattern. A computer identifies pixels whose irradiance changes in response to object movement, and then only irradiance data from the identified pixels is used in analyzing the interferogram to produce a measurement of a surface of the object.

Fringe pattern discriminator for interferometer using diffraction

A Fizeau interferometer (10) producing spherical test and reference wavefronts (34 and 36) is operated with a linear translator (50) for making a sequence of subaperture measurements of an aspherical test surface (40). Separate phase maps (88 and 90) are assembled at different focus positions (54 and 56) along a common optical axis (52) of the interferometer (10) and aspherical test surface (40). Respective null zones (92 and 94) are isolated from the phase maps (88 and 90) and are combined to form a composite phase map (100) defining differences between the aspherical test surface (40) and a family of spheres.

Method of testing aspherical optical surfaces with an interferometer

An interferometer (14) performs three topographical measures of an artifact (12) to determine taper between opposing surfaces (50 and 52) of the artifact (12) mounted on three points of support (30, 32, and 34). Two sets of three data points (60, 62, and 64 and 68, 70, and 72) are extracted from the first topographical measure and are used to calculate irregularities in one of the opposing surfaces (50). The second two topographical measures are made of the other artifact surface (52). Taper between the opposing surfaces (50 and 52) is calculated independently of both the surface irregularities and any angular deviations of the three points of support (30, 32, and 34).

Growing community of inventors

Rochester, NY, United States of America

Jon F Fleig