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:
Jun. 05, 2001
Filed:
Jan. 11, 1999
Yoji Yamamoto, Hyogo, JP;
Masaki Kawasaki, Osaka, JP;
Hideo Koshino, Osaka, JP;
Junya Nakai, Kyoto, JP;
Tetsuya Shimizu, Kyoto, JP;
Matsushita Electronics Corporation, Osaka, JP;
Abstract
In an indirectly heated cathode comprising a heater having an alumina electrical insulating layer formed by layering and sintering alumina particles on a surface of a metal wire and an electron-emitting part that receives heat from the heater and emits thermoelectrons, and a cathode-ray tube comprising the indirectly heated cathode, the alumina particles contained in the alumina electrical insulating layer have a purity of at least 99.7 wt % and the alumina particles used for forming the alumina electrical insulating layer have a Na content of 20 ppm or less or a Si content of 100 ppm or less, thus enabling stable production, avoiding the occurrence of cracks in the alumina electrical insulating layer and heater deformation even in the practical operation of the cathode-ray tube, and lengthening the life of the heater.