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:
Feb. 19, 2008
Filed:
Apr. 14, 2006
Masahiro Nonoguchi, Tachikawa, JP;
Masaru Kuribayashi, Akishima, JP;
Masahiro Nonoguchi, Tachikawa, JP;
Masaru Kuribayashi, Akishima, JP;
Rigaku Corp., Tokyo, JP;
Abstract
An X-ray tube includes an electron gun in which a Wehnelt electrode is formed with an opening asymmetric about an electron emitter. The electron emitter is an elongate coil filament which is disposed inside the elongate opening of the Wehnelt electrode. The opening has two longer sides positioned asymmetrically about a center-of-width line of the filament. Each of the two longer sides is curved in the same direction as viewed in a direction normal to the front face of the Wehnelt electrode. The two longer sides have curvature radii Rand Rdifferent from each other, so that an electron-beam-irradiation region on a target is not curved but becomes almost straight.