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:
Oct. 08, 1991
Filed:
Sep. 06, 1990
Hsing-Yao Chen, Barrington, IL (US);
Richard M Gorski, Arlington Heights, IL (US);
Zenith Electronics Corporation, Glenview, IL (US);
Abstract
Apparatus in a three-beam inline electron gun system for a color cathode ray tube, wherein the tube has a screen and a partially self-converging yoke which partially, but incompletely, converges the three beams and undesirably imparts astigmatism to the beams in off-center regions of the screen, applies a field-strength-dependent asymmetrical field to the two outer beams to provide partial dynamic convergence. The apparatus includes an electron beam source for developing three electron beams, a focusing lens portion for focusing the three electron beams at the tube screen, an astigmatism correcting lens portion for developing an astigmatic field component in the path of each of the beams, and a modulated voltage source for modulating the strength of the astigmatic field component as a function of beam deflection angle to at least partially compensate for the yoke-induced astigmatism and for modulating focus field strength in providing partial dynamic electron beam convergence. The astigmatism correcting lens portion includes an electrode having outer beam apertures shaped to create field-strength-dependent asymmetric outer beam fields and to produce partial dynamic convergence, with the dynamic convergence effects of the yoke, the focusing lens portion, and the astigmatism correcting lens portion combining additively.