Cathode ray tube apparatus
US6404149B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 2000 |
| Grant date | Jun 11, 2002 |
| Priority date | — |
| Expiry date | Feb 24, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J29/503
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electron gun assembly forms an electron beam generator, pre-focusing lens, sub-lens, and main lens. The sub-lens has a weaker horizontal focusing power than the vertical one, and the main lens has a stronger horizontal focusing power than the vertical one. When the electron beam is not deflected, a first quadrupole lens is formed between the pre-focusing lens and sub-lens, and a second quadrupole lens is formed between the sub-lens and-main lens. At least one grid forming each of the first and second quadrupole lenses receives a dynamic focusing voltage which parabolically changes in synchronism with the deflection magnetic field and becomes higher when the electron beam is deflected than when it is not deflected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.