Gray scale pixel driver for electronic display and method of operation therefor
US6809710B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 22, 2001 |
| Grant date | Oct 26, 2004 |
| Priority date | — |
| Expiry date | Jan 22, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2320/0214
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A circuit is disclosed for driving an OLED in a graphics display. The circuit employs a current source operating in a switched mode. The output of the current source is connected to a terminal of the OLED. The current source is responsive to a combination of a selectively set cyclical voltage signal and a cyclical variable amplitude voltage signal. The current source, when switched on, is designed and optimized to supply the OLED with the amount of current necessary for the OLED to achieve maximum luminance. When switched off, the current source blocks the supply of current to the OLED, providing a uniform black level for an OLED display. The apparent luminance of the OLED is controlled by modulating the pulse width of the current supplied to the OLED, thus varying the length of time during which current is supplied to the OLED. By using a switched mode of operation at the current source, the circuit of the present invention is able to employ a larger range of voltages to control the luminance values in a current-driven OLED display.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.