Apparatus for providing contrast and/or brightness control of a video signal
US5317401A · kind A · utility
27Cited by
5References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 15, 1993 |
| Grant date | May 31, 1994 |
| Priority date | — |
| Expiry date | Jun 15, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/57
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention is a video drive apparatus of the two ramp type which includes facility to selectively adjust the brightness and/or the contrast of an image reproduced on a display device. In this apparatus, at least one of the ramp signals is generated digitally by for example a counter. Provision is made to change the counting rate of such counter which effects a change in display contrast. Provision is also made to selectively change the phase of the ramp signal applied to the second stage relative to the start of respective pulses of the PWM signal thereby effecting brightness changes in the reproduced image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.