The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 13, 1988
Filed:
Aug. 13, 1987
Allen P Blacker, Hoffman Estates, IL (US);
Khem K Garewal, Hoffman Estates, IL (US);
Zenith Electronics Corporation, Glenview, IL (US);
Abstract
A color cathode ray tube system is disclosed that has a color tube with a phosphor screend. The system includes yoke means for deflecting the beams while introducing a beam-astigmatizing quadrupole field. A three-beam, in-line electron gun includes cathode means for developing the beams, and three focus lens means for receiving the electron beams and forming three focused electron beam spots at the screen of the tube. The focus lens means each has a plurality of electrode means spaced along a lens axis parallel to the other lens axes and parallel to a gun central axis, at least two of which lens axes are off-axis with respect to the gun central axis. Electrostatic quadrupole-developing means are so configured and arranged as to develop a quadrupole field in the path of each of the beams when appropriately excited, and convergence means are effective to converge the off-axis beams when appropriately excited. System signal generating means provide for developing a signal having amplitude variations correlated with a scan of the beams across the screen and for applying the signal to at least one of the electrode means, to the convergence means, and to the quadrupole-developing means to simultaneously cause, as a function of beam deflection angle, (1) the strength of the one or more focusing field components to weaken to produce a dynamic focusing effect, (2) the strength of the asymmetrical field component affecting the off-axis beams to weaken to produce a dynamic convergence effect, and (3), the strength of the quadrupole field to increase to produce a dynamic astigmatism-correction effect to compensate for the beam-astigmatizing effect of the yoke. The gun system according to the invention provides control of convergence, astigmatism and focus with a single dynamic signal.