Window-dependent brightness/tint control for video digital-to-analog converters
US5638090A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 1, 1994 |
| Grant date | Jun 10, 1997 |
| Priority date | — |
| Expiry date | Dec 1, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/57
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A display control circuit controls the outputs of the three video DACs of an RGB monitor on a window-to-window basis to enable the display of motion video and text on the same screen with different brightness and/or tint. A digital overdrive signal, synchronized to the video DAC digital inputs, is used to enable added DAC elements for the pixels in the video windows only. Stored digital instructions determine how many and which added DAC elements are enabled by the overdrive bit(s). By storing different instructions for each of the three video DACs, the circuit may also provide window-dependent tint control. By increasing the number of bits of digital data synchronized to the digital DAC inputs, the stored instructions may be reduced or eliminated. In this case, each of several windows may be set to differing brightness and tint levels. As many different values of brightness and tint may be available as desired by increasing the number of synchronized input enabling bits and the number and strength of the added DAC elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.