The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 14, 1992
Filed:
Nov. 30, 1990
Francois J Henley, Los Gatos, CA (US);
Stephen Barton, Los Altos, CA (US);
Photon Dynamics, Inc., San Jose, CA (US);
Abstract
Final testing of an LCD panel or the like is performed after preliminary testing for short circuit defects. During final testing, the panel is exposed to signals at the shorting bars and the resulting display pattern is imaged. The resulting image data then is processed at a computer system to determine whether the resulting display pattern differs from an expected display pattern. If differences are present then an open circuit or pixel defect is present. The applied test signals and the pattern or differences determine the type of defect present. For an open circuit defect along a gate line, a partial row (column) of the resulting display pattern does not activate. For an open circuit along a drive line, a partial column (row) of the resulting display does not activate. Pixel shorts are identified by applying test signals to the shorting bars during a first test cycle, then imaging the display during a second test cycle after at least one of the test signals is removed. Pixels which remain active that should be inactive have short circuit defects.