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. 14, 1995
Filed:
Mar. 14, 1994
Applicant:
Inventors:
Chie Takahashi, Nagaokakyo, JP;
Hisakazu Yamane, Nagaokakyo, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ; H01J / ;
U.S. Cl.
CPC ...
315 14 ; 313414 ;
Abstract
An electron gun for a cathode-ray tube has, in addition to its main lens, a triode with first and second grids as control electrodes. The thickness of the second grid, and the separation between the first and second grids, is at most one-half the diameter of the beam aperture in the second grid. These dimensions lead to formation of a prefocus lens with no concave lens component, hence with no beam diverging effect. The resulting triode aberration corrects spherical aberration in the main lens, so that the size of the beam spot focused on the screen has little tendency to increase with increasing beam current.