Patent ID: 7808647
Filing Date: 2010-10-05
Classification: G01B

Abstract:
1. A measuring method for detecting a deviation Δz of a distance z of a plurality of surface points from an objective, comprising the steps of: providing first and second light sources for which the spectral centroids differ by the wavelength difference Δλ and which produce spectral components comprising a first signal frequency f dividing the light from the first and second light sources into a measuring light beam and a reference light beam; simultaneously directing the measuring beam onto a two dimensional matrix of surface points and, following reflection by the matrix of surface points, combining the reference and measuring beams and directing the combined beam onto a photo receiver, whereby a length of a measuring light path traversed by the measuring light beam is changed relative to a length of a reference light path traversed by the reference light beam; from a time-variant measuring signal containing spectral components produced by the photo receiver, extracting the two spectral components comprising a first signal frequency f determining the relative phase angles φ determining the deviation Δz from the difference between the respective phase angles φ