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US 5,204,617 AGranted
Liquid crystal panel inspection method
AssigneeEzel, Inc.
InventorRyohei Kumagai
Life of this patent
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Abstract
An inspection method of liquid crystal panel by comparing characteristics of histogram of a part mounted on the panel with a reference histogram which is obtained from a part of the panel to be inspected.
Claims9
An inspection method of liquid crystal panel for judging if a part of said liquid crystal panel is defective or not comprising steps of:
- taking an image of said liquid crystal panel with lighting said panel;
- calculating histograms of parts mounted on said liquid crystal panel from said image;
- classifying said parts into groups according to characteristics value of said histogram;
- selecting one group with maximal number of members from said groups;
- selecting a reference histogram from histograms of said parts of said group selected;
- and
- comparing histograms of parts belonging to other groups than said groups selected with said reference histogram so that a defective part is extracted as defective part when a difference is greater than a predetermined value between said histogram of said parts of said other groups and said reference histogram.
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