Shadow mask for color CRT
US6072270A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 1998 |
| Grant date | Jun 6, 2000 |
| Priority date | — |
| Expiry date | Jun 22, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J29/076
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In a shadow mask employed as a color selection electrode in a multi-electron beam color cathode ray tube (CRT), the surface area of the mask is reduced by increasing the length of the individual elongated beam passing apertures, or slots, while reducing the ratio of the width of the bridge portion of the mask between adjacent apertures to the length of the aperture. Increasing the length of the apertures while reducing the ratio of bridge width to aperture length reduces the surface area of the mask upon which energetic electrons are incident resulting in a corresponding reduction in thermal deformation, or doming, of the shadow mask. Reduction in shadow mask doming results in reduced landing shift of the electron beams incident on phosphor elements disposed on the inner surface of the CRT's display screen for improved video image brightness and color purity. More specifically, in a shadow mask having a thickness in the range of 0.12-0.18 mm with slotted apertures, the length of the slots is in the range of 0.90-10.00 mm and the ratio of bridge width to slot length is in the range of 0.001-0.110. With this invention, electron beam transmission through the shadow mask can be increas…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.