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1. (WO2018200350) RADIUS-OF-CURVATURE MEASUREMENT BY SPECTRALLY-CONTROLLED INTERFEROMETRY

Pub. No.:    WO/2018/200350    International Application No.:    PCT/US2018/028796
Publication Date: Fri Nov 02 00:59:59 CET 2018 International Filing Date: Tue Apr 24 01:59:59 CEST 2018
IPC: G01B 11/24
G01B 9/02
G01B 9/023
G01B 11/30
G01B 21/20
Applicants: APRE INSTRUMENTS, LLC
OLSZAK, Artur
Inventors: OLSZAK, Artur
Title: RADIUS-OF-CURVATURE MEASUREMENT BY SPECTRALLY-CONTROLLED INTERFEROMETRY
Abstract:
The ROC value of a test surface (14) is measured with a single spectrally- controlled interferometric measurement using a reference source (18) of known ROC. The test surface is placed at the confocal position (24) of the reference surface and the light source (16) is modulated so as to produce localized interference fringes (30-34, 36-40, 42-46) at the location of the test surface. The interference fringes are then processed with conventional interferometric analysis tools to establish the exact position of the test surface in relation to the reference surface, thereby determining the distance between the test surface and the reference surface. The radius of curvature of the test surface is obtained simply by subtracting such distance from the known radius of curvature of the reference surface.