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Method and apparatus for defect detection and location

  • US 4,943,732 A
  • Filed: 08/16/1989
  • Issued: 07/24/1990
  • Est. Priority Date: 08/16/1989
  • Status: Expired due to Fees
First Claim
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1. Apparatus for locating defects in a substantially planar liquid crystal display (LCD) panel, the apparatus comprisinglight source means for generating an interrogating light beam to impinge upon the LCD panel,scanning means for introducing relative motion between said interrogating light beam and the LCD panel to scan said interrogating light beam in a predetermined pattern about the LCD panel,position signalling means for generating a position signal having an instantaneous value representative of an instantaneous position of said interrogating light beam with respect to the LCD panel,photodetector means fordetecting any of reflected, refracted, scattered or transmitted light resulting from impingement of said interrogating light beam upon the LCD panel, andgenerating in response thereto a detector signal having an instantaneous value representative of detected magnitude of said reflected, refracted, scattered or transmitted light,each said instantaneous detector signal value corresponding with the instantaneous position of said interrogating light beam with respect to the LCD panel, anddiscontinuity detection means, responsive to said detector signal, for detecting discontinuities in the value of said detector signal, said discontinuities being representative of defects in the LCD panel, said discontinuity detection means includinglocation means, responsive to said detector signal and said position signal, for correlating each said discontinuity in the value of said detector signal with a corresponding location on the LCD panel to assign a location to each detected defect on the LCD panel.

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