Eastman-Kodak Company

David Pileri

John J Hannon

Donald A Gildner

Mark Baumler

A method for interferometrically determining error continuously in the radius of curvature of a planetary polishing surface and for providing compensating correction of the surface shape while the polishing machine is in operation. A conditioner glass body disposed on the polishing surface for reshaping the surface is itself a Fizeau cavity having upper and lower partially-reflective surfaces which are parallel or slightly non-parallel for plano polishing and spherical polishing. The conditioner is illuminated by a plano, monochromatic, coherent light wavefront substantially perpendicular to the polishing surface, preferably over the entire upper surface of the conditioner. A portion of the incident wavefront is reflected from the upper surface as a reference wavefront, and another portion of the incident wavefront is reflected from the lower surface as a measurement wavefront. The two reflected wavefronts are directed to an electronic camera in which the wavefronts cancel and reinforce to form interference fringes indicative of the curvature of the lower surface of the conditioner.

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Fairport, NY, United States of America

David Pileri