Apparatus for applying voltages to individual columns of pixels in a color electro-optic display device
US6384817B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1999 |
| Grant date | May 7, 2002 |
| Priority date | — |
| Expiry date | Dec 21, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2320/02
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an electro-optic display device, such as a liquid crystal display device which serves as a modulator for projected light, a global ramp generator is used in conjunction with track and hold circuits to convert incoming digital display signals to analog signals, and to address the individual pixels of the display device with such analog signals. A plurality of column drivers, each coupled to the ramp generator and to the pixels in a column of the display device, track and hold the ramp voltage signal when it reaches a value corresponding to the desired brightness level of a particular pixel in the respective column. At least one current source is provided, coupled to the signal source output, for supplying current to the signal source output, as needed, to compensate for switching the capacitive load of the column drivers on and off. As a result, transient voltages in the ramp signal are avoided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.