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. 02, 1982
Filed:
Sep. 24, 1979
Richard H Hughes, Lancaster, PA (US);
Hsing-Yao Chen, Landisville, PA (US);
RCA Corporation, New York, NY (US);
Abstract
The electron gun, which is especially adapted for use in color picture tubes, comprises in the order named: a cathode, an apertured-plate control grid (G1), an apertured-plate screen grid (G2), and at least two tubular focusing electrodes. The quality of the gun's beam spot is improved by: 1. Establishing an operating electric field between the G2 and G3 which is between about 100 and 400 volts/mil, thereby reducing aberration effects in the beam-forming region of the gun; 2. Making the G2 thick so as to prevent the high G3 voltage from penetrating the region between the G1 and G2, thereby allowing the G1-G2 field to provide a divergent effect on the electron beam prior to beam crossover and thus give a reduced crossover angle; 3. Spacing the main focusing lens at a distance from the G2 so as to provide an optimum filling of the main focus lens with the beam to maximize the object distance of the focusing system; and 4. Structuring the G2 and G3 to provide a flat electrostatic field therebetween to avoid prefocusing action in that region, so as not to cause an effective reduction of the object distance of the focusing system.