Method and apparatus for driving capacitive display device
US5311169A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1991 |
| Grant date | May 10, 1994 |
| Priority date | — |
| Expiry date | Jul 26, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2320/0223
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
This invention relates to gradation display by a pulse width control method (PWM method) in every pixel in a capacitive display apparatus such as a liquid crystal display apparatus. The driving voltage applied to the electrodes is varied slowly, and the number of gradations of gradation display by the PWM method is increased. Since the capacitive display apparatus is used, for each electrode further from the drive circuit, the driving pulse is more influenced and its persisting duration is extended. As a result, even in identical gradation data, uneven colors may occur. The pulse width applied to the electrodes is gradually decreased as scanning of the electrodes sequentially occurs. Therefore, the brightness of the capacitive display apparatus may be made uniform over the entire screen surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.