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:
Nov. 01, 1988
Filed:
Dec. 21, 1987
Steven E Shields, San Diego, CA (US);
James E Cooper, Jr, San Marcos, CA (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
An on-substrate driver circuit for a display line of a liquid crystal display having an amplifier connected in conjunction with an amplifier input capacitor, a sample/hold capacitor and three switches. The circuit operates in a first compensation mode wherein the first and second of the switches connect both a null reference voltage and the amplifier output voltage to the amplifier input capacitor, effectively nulling out or compensating for offset between the turn-on threshold, and hence the output, of a plurality of amplifiers on the display. After compensation, the circuit is switched to an operational mode wherein the first and second switches are open and a third switch connects the analog display signal to the sample/hold capacitor. A second preferred embodiment employing a double buffer including two consecutive, serially connected amplifier stages as described is also disclosed. In practice, a plurality of such double buffer circuits are arranged along the edge of a liquid crystal display panel and supplied with a common input signal by a single off-substrate input signal line.