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:
May. 04, 1999
Filed:
Oct. 13, 1995
Kenichi Ishiguro, Tenri, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
An insulated gate TFT (thin film transistor) liquid crystal pixel device driving circuit includes a supplemental capacitive element (condenser) that has the following two insulating films that is sandwiched between one electrode made of non-single crystal (semi-conductive) silicon and another electrode made of a conductor: (1) an insulating silicon-oxide film; (2) an insulating film made of the same material that was used for insulating the gate of the pixel TFT. The supplemental capacitive element is specifically provided with a thicker insulating film portion compared to that of the pixel TFT. Consequently, if the TFT gate insulating film is somehow subsequently thinned, the supplemental capacitive element is less susceptible to the occurrence of defects such as pin holes or the like. As a result, not only is the performance of the pixel TFTs upgraded, but also the reliability of the associated supplemental capacitive elements is increased. Thus, the method and apparatus in accordance with the present invention makes it possible to provide an inexpensive liquid crystal display device having improved performance over conventional TFTs combined with a greater reliability and an increased resistance of the supplemental capacitive elements to voltage spikes or the like.