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. 12, 2006
Filed:
Mar. 25, 2003
Yasuhiro Kumamoto, Neyagawa, JP;
Taro Funamoto, Mino, JP;
Katsuyuki Arimoto, Okayama, JP;
Matsushita Electric Industrial Co., LTD, Osaka, JP;
Abstract
A doubler part doubles frequencies of video signals. A drive control circuit generates, in response to a synchronizing signal outputted from the doubler part, PWM dimming frequency information such that a PWM dimming frequency f and a black display ratio B satisfy the relationships f≧25B+250 and B>10, and provides such information to a PWM dimming signal generation circuit. In addition, the drive control circuit drives a gate driver and a source driver such that one frame period is divided into an image display period and a black display period. The PWM dimming signal generation circuit generates, in response to a synchronizing signal and the PWM dimming frequency information, a PWM dimming signal and provides the PWM dimming signal to a lighting circuit. The lighting circuit activates a backlight device with dimming, in response to the PWM dimming signal. This configuration reduces colored interference fringes in a liquid crystal display device resulting from the combination of a black insertion drive technique and a PWM dimming technique.