Shadow mask for a cathode ray tube with defined beam passages holes
US7471036B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 2006 |
| Grant date | Dec 30, 2008 |
| Priority date | — |
| Expiry date | Jul 20, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J29/81
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A shadow mask for a cathode ray tube has an effective screen portion having a plurality of beam passage holes arranged in a predetermined pattern, and an inactive portion with no beam passage holes. The length of a beam passage hole at a column adjacent to a division between the effective screen portion and the inactive portion (hereinafter “the beam passage hole length”) in the long-sided direction is set to be smaller than the length of a beam passage hole placed at the short-sided center of the column. The beam passage hole length “a” at columns which are even-numbered from the long-sided center of the effective screen portion is set to satisfy the condition of 1>a/A≧0.45, compared to the length A of the beam passage hole placed at the short-sided center of relevant columns. The beam passage hole length “b” at columns which are odd-numbered is set to satisfy the condition of 1>b/B≧0.35, compared to the length B of the beam passage hole placed at the short-sided center of relevant columns.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.