Method and apparatus for improving vertical sharpness of picture tubes
US5396157A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 19, 1993 |
| Grant date | Mar 7, 1995 |
| Priority date | — |
| Expiry date | Apr 19, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N3/30
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Large format TV tubes must produce a high peak brightness in order to be acceptable to the user. This results in a large beam current in bright areas of the picture and in a subsequent defocusing of the resulting spot on the display and in a loss of the sharpness of vertical and horizontal transitions. The apparent sharpness of a vertical transition is gained by modifying the deflection of the TV receiver such that, at vertical transitions, the line on the bright side of the transition is deflected away from the transition region. Advantageously, the amount of vertical scan modulation corresponds to a multi-level control signal and depends on the grey levels of the transition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.