Patent ID: 8154733
Filing Date: 2012-04-10
Classification: G01B,G01M

Abstract:
1. A system for optically measuring large radii of curvature of optical functional surfaces, comprising an interferometer and a supplementary lens disposed downstream in the beam direction to fit a plane wavefront of a test wave transmitted by said interferometer to a specified curvature of a nominal surface for a test surface, a mount for a specimen, a mechanism for moving the mount along an optical axis of the supplementary lens, and a path measuring system for measuring a path of movement, said supplementary lens being a supplementary dual-focus lens having a second focal plane in a focus position disposed at a distance (D(foc)) from a first focal plane, and said mount being positioned such that a surface vertex of a test surface of said specimen in the mount is located in the first focal plane, thereby establishing a cat's eye position, said mount being moveable by a path of movement to move a center of curvature of the test surface into the focus position, which establishes an autocollimation position.