Device for the dual loop servo-control of the cut-off voltage of a cathode-ray tube
US5266872A · kind A · utility
0Cited by
4References
19Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 21, 1992 |
| Grant date | Nov 30, 1993 |
| Priority date | — |
| Expiry date | Aug 21, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/57
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The disclosure relates to cathode-ray tubes that have to be used at a low level of luminance. The cut-off voltage of the tube is modified by using two servo-control loops, the first one as a function of the value of the cathode current and the second one as a function of the luminance value of a zone that is located outside the operational image of the screen and consists of a particular luminophore. Selector means are used to change over from one loop to the other and vice versa as a function of the values of the cathode current and of the luminance of the zone with respect to certain predetermined thresholds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.