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. 22, 1994
Filed:
Apr. 12, 1993
Masami Oguriyama, Ichikawa, JP;
Yoshio Ishigaki, Ichikawa, JP;
Haruo Okano, Tokyo, JP;
Isahiro Hasegawa, Zushi, JP;
Jun-ichi Arami, Hachioji, JP;
Hiromi Harada, Hiratsuka, JP;
TDK Corporation, Tokyo, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Tokyo Electron Limited, Tokyo, JP;
Abstract
A permanent magnet magnetic circuit is provided capable of producing a unidirectional magnetic field substantially free of unnecessary perpendicular magnetic field components. A pair of main magnetic poles of opposite polarities are situated at a pair of opposite edge surfaces of a permanent magnet block for producing lines of magnetic force. One major surface of the block between the edge surfaces is provided with a channel where a pair of auxiliary magnetic poles are situated at opposed inner surface portions of the channel for controlling a middle portion of the lines of magnetic force to be linear.