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:
Mar. 11, 1997
Filed:
Mar. 28, 1995
Hsing-Yao Chen, Barrington, IL (US);
Chunghwa Picture Tubes, Ltd., Taoyuan, TW;
Abstract
An electron gun for use in a cathode ray tube (CRT) includes a cathode, a low voltage beam forming region (BFR), and a high voltage deflection focus lens disposed in the beam deflection region of the CRT's magnetic deflection yoke for simultaneous and coincident focusing and deflection of the electron beam on the CRT's display screen. The deflection lens includes a plurality of first focus grids disposed in the CRT's neck portion including a spaced first pair of grids (G42, G44) having respective beam passing apertures disposed horizontally off-center in opposed directions relative to the electron beam axis, and a second pair of grids (G46, G48) having respective beam passing apertures disposed vertically off-center in opposed directions relative to the axis. Other grids disposed on opposed sides of each of the first and second pair of grids have respective beam passing apertures centered with respect to the electron beam axis and are maintained at a fixed focus voltage. A first dynamic focus correction voltage source (275) and a second dynamic focus correction voltage source (277) which vary with the electron beam deflection are respectively applied to each of the first and second pair of grids for compensating for asymmetric off-axis electron beam defocusing at all points on the CRT's faceplate. This dynamic off-axis defocusing correction is equally applicable in a single beam, monochromatic deflection lens CRT, as well as in a multi-beam, color deflection lens CRT.