Method to control CRT phosphor aging
US6359398B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 1999 |
| Grant date | Mar 19, 2002 |
| Priority date | — |
| Expiry date | Nov 29, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7408
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus are provided for equally aging a cathode ray tube (CRT). A video input terminal is coupled to the CRT and receives an external video signal. Control circuitry is provided, which detects the aspect ratio of the signal and determines whether there is a mismatch between the signal aspect ratio and an aspect ratio of a display screen in association with the CRT. If a mismatch between the signal aspect ratio and the screen aspect ratio exists, an equalization video signal is derived from the external video signal. A primary region of the CRT is illuminated in response to the external video signal, and a secondary region of the CRT, which would otherwise be unilluminated in response to the external video signal due to the mismatch between the signal aspect ratio and the screen aspect ratio, is illuminated in response to the equalization video signal. In this manner, the CRT is uniformly aged.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.