Device to shield mask cathode tubes from the earth's magnetic field
US4940920A · kind A · utility
8Cited by
4References
3Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 6, 1987 |
| Grant date | Jul 10, 1990 |
| Priority date | — |
| Expiry date | Nov 6, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2229/0053
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
To improve the trichromatic cathode tube shielding effect given by the frame-mask set and by a shielding material made with material of low magnetic permeability, the external conductors of a de-magnetization coil with two loops are made to pass in front of the fastening lugs and not behind the frit plane as was the case before, and the position of the internal conductors is set to obtain the best compromise.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.