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. 20, 1987
Filed:
Oct. 20, 1986
Allen P Blacker, Hoffman Estates, IL (US);
Wayne R Chiodi, Northbrook, IL (US);
Zenith Electronics Corporation, Glenview, IL (US);
Abstract
An electron gun system providing beam convergence is disclosed for use in a color CRT display system. Means including cathode means develop three electron beams, two of which are off-axis with respect to a center axis of the gun. A plurality of electrodes means provide shaping and focusing, and assisting in the converging of the beams at the tube screen. Means are provided for developing and applying to the electrode means a pattern of potentials which form field components in the gaps therebetween; at least one of the electrode means receives a varying dynamic focusing voltage for dynamically focusing the beams as they are deflected across the screen. At least selected ones of the plurality of electrodes means for the off-axis beams are so structured and arranged as to cause a plurality of the field components to be asymmetric and effective to converge the off-axis beams. The strengths of the asymmetric field components vary in response to changes in the dynamic focus voltage. The asymmetric field components according to the invention have such polarity and strength, due to the structuring and arranging of the electrodes, and the application of the pattern of voltages, that a change in the levels of the dynamic focus voltage causes a change in the strength of each of the asymmetric field in a direction effective to additively deflect a common off-axis beam in a common angular direction so as to create a strong dependency of the convergence of the off-axis beams on variations in the focus voltage.