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:
Jan. 07, 2003
Filed:
Jun. 09, 2000
Hitachi, Ltd., Tokyo, JP;
Abstract
A cathode ray tube is provided with a phosphor screen and an electron gun including a cathode having an electron-emissive material layer formed on a surface of a cathode base metal. The electron-emissive material layer includes a first layer made of an alkaline earth metal oxide on the surface of the cathode base metal, a second layer on a surface of the first layer which is an alkaline earth metal oxide layer containing at least one rare earth metal oxide in a range of 0.1 to 10 weight percent, the at least one rare earth metal oxide having a particle size distribution in which the number of particles having a maximum diameter over 5 &mgr;m m is one or none, the number of particles having a maximum diameter in a range of from 1 &mgr;m to 5 &mgr;m is in a range of from 2 to 30, as measured in an area of 45 &mgr;m×45 &mgr;m at a center of a top surface of the second layer, the maximum diameter being defined as a perpendicular projection, onto a horizontal direction, of tangents to extremities of a profile of each of the particles. The cathode base metal is made chiefly of nickel and containing at least one reducing agent, and a thickness of a portion of the cathode base metal in contact with the electron-emissive material layer is in a range of 0.10 to 0.16 mm.