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:
Dec. 08, 1998
Filed:
Jul. 03, 1996
Yasuaki Muto, Toyonaka, JP;
Hiroshi Miyai, Takarazuka, JP;
Akio Takimoto, Nayagawa, JP;
Yasunori Kuratomi, Sulta, JP;
Toshikazu Kawakami, Osaka, JP;
Hiroshi Noguchi, Ibaraki, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In a projection type video display device comprising a light writing type spacial light modulator, disturbances brought about by a resetting pulse and appearing in a projected picture as a black belt or beat are prevented. This is accomplished by causing the resetting pulse, which is to withdraw electric charges produced by incoming writing light and accumulated in spacial light modulator, to occur within a vertical blanking period synchronized with vertical synchronization signal. Further, by changing the pulse width and the voltage of the resetting pulse in accordance with vertical synchronization frequency, pictures of a certain fixed brightness are made available against various vertical synchronization frequencies; and even with a high vertical synchronization frequency, projected pictures are never annoyed by such disturbance that is caused by a resetting pulse dislocated out of the vertical blanking period. Further, by controlling the adjustments of the writing voltage to be applied to the spacial light modulator during the writing period and the resetting voltage to be applied to the spacial light modulator during the resetting period, the spread in characteristics of the spacial light modulator is compensated to provide a certain fixed contrast and .gamma. characteristic. Furthermore, in a video display device for full-color display, writing voltage and resetting voltage can be established independently corresponding to the respective three RGB primary colors, video outputs of any desired color temperature are obtainable by adjusting the balance of light emission among the three RGB colors.