Lens aperture structure for diminishing focal aberrations in an electron gun
US6452320B1 · kind B1 · utility
Assignees
Inventor
Key dates
| Filing date | Aug 9, 2000 |
| Grant date | Sep 17, 2002 |
| Priority date | — |
| Expiry date | Aug 9, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J29/624
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A main lens of an electron gun of a cathode ray tube is provided. The main lens for receives a plurality of parallel and co-planar electron beams emitted by the electron gun. The lens focuses each electron beam along a respective one of a plurality of focal axes incident to a display surface. A first grid electrode is positioned substantially orthogonally with respect to the plurality of electron beams, the grid electrode includes a plurality of apertures. Each aperture focuses a respective one of the plurality of electron beams, each aperture is centered about a respective one of said focal axes and has a shape expressed by the equation (1): where a and b define the horizontal and vertical axis lengths, &thgr; is an angle, which varies between 0° and 360°, with respect to the x axis, of a line between the origin (x=0, y=0) and a point on the edge of the aperture and the exponent n determines the deviance from ellipticity, and where 1<n<2. The shape of the plurality of apertures diminishes focal aberrations of the lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.