Color cathode-ray tube apparatus with shadow mask
US4369396A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 29, 1980 |
| Grant date | Jan 18, 1983 |
| Priority date | — |
| Expiry date | May 29, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2231/121
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In shadow mask color cathode-ray tube apparatus, the shadow mask is provided with slits or rows of slots extending from side to side of the mask and a line raster is constrained so that the lines of the raster are colinear with the slits, there being just one slit to each line of the raster. Open loop control may be used to achieve colinearity, but closed loop control is preferred. Beam position signals may be drived from the shadow mask by sensing secondary emission from different phosphors on the gun side of the mask or be sensing currents generated in the mask. In the preferred embodiment, the beams are dithered as they traverse the raster and the difference in the currents generated by a beam at the mask and at the conductive layer at the tube screen is detected. The first fundamental of the difference current indicates by its amplitude and phase the amount and direction of the misregistration of a beam and a slit. Different beams are distinguished by frequency multiplexing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.