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. 12, 2004
Filed:
Oct. 14, 2002
Applicant:
Inventors:
Masahiro Kato, Mobara, JP;
Tomohiro Yamada, Mobara, JP;
Assignee:
Futaba Corporation, Chiba-ken, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J 1/14 ;
U.S. Cl.
CPC ...
H01J 1/14 ;
Abstract
A directly-heated oxide cathode and a fluorescent display tube using the same, which works with low power consumption, is provided. In a filament cathode, an alkaline earth oxide having an average grain size of 0.1 &mgr;m to 2.0 &mgr;m is coated in a thickness of 0.5 &mgr;m to 4.0 &mgr;m on the surface of a core metal wire. This structure reduces the power consumption of the filament cathode. The filament cathodes mounted in a fluorescent display tube can reduce the power consumption of the fluorescent display tube.