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:
Sep. 07, 1993
Filed:
May. 13, 1992
Henry P Hall, Concord, MA (US);
Paul R Pilotte, Arlington, MA (US);
GenRad, Inc., Concord, MA (US);
Abstract
A test method for a switch matrix (10) of a liquid-crystal display employs a signal source (40, 42) to drive a row line (20) of the matrix and employs current sensors (56, 58, and 60) to measure the resultant current flow. Errors are detected by observing departures of the measured currents from expected values. To increase the sensitivity of the current measurement to the capacitance in the location at which the associated column line (14, 16, or 18) intersects the driven row line (20), return connections for the source (40, 42) are made directly to the contact pads (26, 28) of the row lines not currently being driven and column lines not currently being sensed.