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.

Date of Patent:
Jan. 30, 1990

Filed:

Oct. 05, 1987
Applicant:
Inventors:

Masato Saito, Kanagawa, JP;

Keiji Fukuyama, Kanagawa, JP;

Masako Ishida, Kanagawa, JP;

Keiji Watanabe, Kanagawa, JP;

Toyokazu Kamata, Kyoto, JP;

Kinjiro Sano, Kyoto, JP;

Hisao Nakanishi, Kyoto, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
3133 / ; 313345 ;
Abstract

A hot cathode in a wire form is useful in a vacuum tube, a CRT or a fluorescent display tube is disclosed. The cathode is composed of a heat-resistant metal in a wire form that holds on it an electron-emitting metal material that is made of 0.2-20 wt % of a rear earth metal oxide in admixture with an alkaline earth metal oxide the balance of which contains at least barium oxide. The reduction of oxide barium to barium as a result of reaction with the cathode wire is so much retarded that an increased emission current will be produced from the cathode not only in its initial operation but also through out its operation.


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