Color cathode-ray tube having a three-lens electron gun
US4764704A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 1987 |
| Grant date | Aug 16, 1988 |
| Priority date | — |
| Expiry date | Dec 4, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2229/4896
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention provides an improvement in color cathode-ray tubes. Such tubes include an electron gun for generating and directing three inline beams, a center beam and two side beams, along initially coplanar paths toward a screen of the tube. The gun includes a plurality of spaced electrodes which provide a first, a second and a third lens for focusing the electron beams. The first lens has a beam forming region for providing substantially symmetrical beams to the second lens. The improvement comprises the combination of the second and third lens. The second lens includes at least one electrode to provide asymmetrically-shaped beams. The potentials applied to the second lens refract electron beams emerging off-axes from the first lens toward the axes. The third lens is a low aberration main focusing lens which provides asymmetrically-shaped beams of substantially constant current density to the screen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.