Patent ID: 9644947
Date: 2017-05-09
CPC Classifications: G01B

Claim:
1. An optical interferometric apparatus for real-time thickness inspection, comprising: a light source comprising a laser source generating a laser beam; a spatial-filter point-expanded device; and a beam steering device located between the laser source and the spatial-filter point-expanded device so as to guide the laser beam to a determined position and direction and wherein the spatial-filter point-expanded device filters spatial noise in a light field and uniformly expands the laser beam to obtain a wide-area high-coherence point-expanded spherical-wavefront light beam; a screen located at a lateral side of said light source, wherein an interference fringe pattern (IFP) is imaged on said screen by illuminating said high-coherence point-expanded spherical-wavefront light beam on an object located between the spatial-filter point-expanded device and the screen in an oblique angle of an optical axis of the spatial-filter point-expanded device; an image acquisition unit located in front of said screen and capturing a single exposure of said IFP on said screen and converting the image into a single exposure digital image of said IFP for each object; and an image processing module connected with said image acquisition unit and comprising an analysis software unit having functions of thickness measurement, digital image access, and image analysis of the digital image of the IFP and a drawing software unit analyzing data from the analysis software unit and visualizing the analyzed digital image data to obtain a full-field thickness distribution of said object from the single exposure digital image of the IFP for each object.