Flat cathode-ray tube, electron gun for flat cathode-ray tube and producing method thereof
AssigneeSony Corporation
InventorsJun Miura, Koichi Furui
Life of this patent
Estimating the term…
Abstract
In a flat cathode-ray tube, there are problems that an axis of electron beam is separated before the electron beam enters a main lens due to magnetic field of a magnet disposed outside a neck, and coma aberration is generated to degrade an image quality. It is an object of the present invention to solve these problems. A flat cathode-ray tube comprises an electron gun 281 having a main lens 35M whose center coincides with a tube axis, a deflection yoke, and a magnet disposed outside a neck. An axis of a prefocus lens of the electron gun is separated from the tube axis.
Claims6
An electron gun for a flat cathode-ray tube comprising a cathode and a plurality of grids, characterized in that a prefocus lens is separated from a center axis of an electron gun in a direction in which an axis-separating amount of an electron beam caused by a magnetic field of a magnet which is disposed outside of a neck becomes smaller;
- and
- means for correcting the electron beam whose axis is separated so that said electron beam passes through a center of a main focus lens, whereupon halation caused by coma aberration is reduced and resolution is enhanced.
An electron gun for a flat cathode-ray tube comprising a cathode and a plurality of grids, characterized in that a prefocus lens is separate from a center axis of an electron gun in a direction in which an axis-separating amount of an electron beam caused by a magnetic field of a magnet which is disposed outside of a neck becomes small, and further characterized in that centers of electron beam through holes of first and third grids of the plurality of grids coincide with a center axis of the electron gun, and a center of an electron beam through hole of second grid is separated from the center axis.
An electron gun for a flat cathode-ray tube, characterized in that a prefocus lens is separated from a center axis of an electron gun in a direction in which an axis-separating amount of an electron beam caused by a magnetic filed of a magnet which is disposed outside of a neck becomes smaller, and further characterized in that centers of electron beam through holes of first and third grids of the plurality of grids coincide with a center axis of the-electron gun, and an end surface having an electron beam through hole of a second grid is inclined with respect to the center axis.
Dependencies are inferred from the claim text.