Vertical deflection circuit with raster correction
US6081078A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 1996 |
| Grant date | Jun 27, 2000 |
| Priority date | — |
| Expiry date | May 17, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N3/22
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An electron beam tends to slope downwardly as it is deflected horizontally to form a raster in a video display apparatus. The sloping of the beam can cause geometric errors in the raster, for example orthogonality and parallelogram errors. A raster correction circuit substantially offsets the downward slope of the electron beam by modulating a vertical deflection current with an induced horizontal-rate raster correction current, thereby substantially eliminating orthogonality and parallelogram errors in the raster. In respective embodiments of an inventive arrangement taught herein, the horizontal-rate raster correction current is induced in the vertical deflection coils by magnetically coupling a filament pulse waveform, a horizontal deflection voltage waveform, or a horizontal deflection current into the vertical deflection coils.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.