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:
Dec. 25, 1990
Filed:
Sep. 13, 1988
Masaaki Yamauchi, Togane, JP;
Yasuo Tanaka, Ichihara, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Device Engineering Co., Ltd., Chiba, JP;
Abstract
An electron beam focusing device for use in a cathode ray tube (CRT) including a first and a second conductor film each formed on the inner surface of a neck portion of the CRT, which are spaced apart from each other by a predetermined distance, and a resistive conductor film which connects the first and second conductor films with each other. The first conductor film is located before the second conductor film in a beam travelling direction. The additional conductor film has a higher resistivity than that of the first and second conductor films. The first conductor film is set at a higher potential than the second conductor film. A dark current flowing from a high potential side through the first conductor film, the resistive conductor film and the second conductor film produces a voltage drop across the resistive conductor film so that the surface potential of the resistive conductor film is stabilized, thus forming an electrostatic lens with a stabilized electric field.