Projection cathode ray tube having an interference filter
US5138222A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 1990 |
| Grant date | Aug 11, 1992 |
| Priority date | — |
| Expiry date | Jun 22, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2229/8916
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A projection cathode ray tube has an interference filter which is disposed at a boundary between a face plate and fluorescent layers. The interference filter is designed to be thinnest at the central area of the CRT and to become gradually thicker toward the peripheral area of the CRT, so that the CRT can produce a uniformly bright image over the central and peripheral areas. The fluorescent layers include a first layer composed of small fluorescent particles and a second layer composed of large fluorescent particles. With this first fluorescent layer, light beams emitted by the second fluorescent layer can be prevented from being reflected in multiple directions, thereby minimizing halo due to such multi-direction reflection of the light beams.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.