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:
May. 17, 1988
Filed:
Jul. 20, 1987
Roger C Alig, West Windsor Township, Mercer County, NJ (US);
RCA Licensing Corporation, Princeton, NJ (US);
Abstract
The present invention provides an improvement in color picture tubes. Such tubes include an electron gun for generating and directing three inline electron beams, a center beam and two side beams, along initially coplanar paths toward a screen of the tube. The gun includes a plurality of spaced electrodes which form a main focus lens for focusing the electron beams. The improvement comprises the plurality of spaced electrodes which form a main focus lens including three electrodes that form an einzel lens in the path of each electron beam. A first einzel lens electrode includes three inline cylinders through which the electron beams pass. A second einzel lens electrode includes a large oval cylinder that overlaps all three cylinders of the first einzel lens electrode. A third einzel lens electrode includes three inline cylinders which are overlapped by the oval cylinder. The oval cylinder includes means for shaping the main focus lens to focus the three electron beams stigmatically near ground potential and to converge the outer beams at the center of the screen.