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:
Oct. 22, 1991
Filed:
Mar. 15, 1991
Kuninori Matsumi, Fujisawa, JP;
Tadahiro Kawagishi, Yokohama, JP;
Masahiro Kame, Kasukabe, JP;
Makoto Shiomi, Dumont, NJ (US);
Kousuke Ozeki, Yokohama, JP;
Michitaka Ohsawa, Fujisawa, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Video Engineering Inc., Kanagawa, JP;
Abstract
The digital convergence correction device is used for a projection-type television receiver having a Braun tube with an aspherical surface fluorescent screen and a projection lens system with an aspherical surface plastic lens attached to the display screen of th Braun tube. In the digital convergence correction device, a digital memory stores digital correction data corresponding to correction values at the convergence adjustment points on the display screen that is divided in the horizontal and vertical directions. A multiplexer reads the digital correction data out of the digital memory, and implements the time division multiplexing for the data. A D/A converter receives the multiplexed data from the multiplexer, and converts it into an analog signal. The device is provided with sample-holding circuits for making coincident timing for the outputs of the time division multiplexing process, so that no phase shift arises at the time division process and multi-channel time division process is made possible. Among numbers of time divisions, an optimal one can be chosen to meet the system requirement. Consequently, the number of D/A converters is reduced thereby to down-cost the digital convergence correction device. The convergence correction device operates in accordance with the correction signals held in the respective sample-holding circuits.