Method and system for the optical measurement of large radii of curvature of optical functional surfaces

US8154733B2 · kind B2 · utility

Assignee

• Jenoptik Optical Systems GmbH · DE

Inventors

• Stefan Franz · Munich, DE
• Roland Schreiner · Orlamünde, DE

Key dates

• Filing date: Sep 24, 2009
• Grant date: Apr 10, 2012
• Expiry date: Sep 2, 2030

Classification

• Technology area (CPC G): Physics
• CPC primary: G01M11/0271
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The system and the method of the present invention differ from the prior art in that radii of curvature of any length of spherical and cylindrical test surfaces can be optically measured, with only a supplementary dual-focus lens being required in addition to an interferometer or an autocollimator. The supplementary dual-focus lens has a first focal plane, into which the surface vertex of the test surface is positioned, which establishes the cat's eye position (P(cat)), and a second focal plane into which the center of curvature of the test surface is moved, which establishes the autocollimation position (P(aut)) for the test surface. The radius of curvature of the test surface is determined from the distance between the focal planes (D(foc)) and the path of movement which can be reduced to zero.