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:
Sep. 29, 1987
Filed:
Feb. 05, 1986
Isao Sakaguchi, Odawara, JP;
Tatsuo Kawaide, Odawara, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A method of orienting magnetic particles in the thin magnetic film of a magnetic disc in the circumferential direction of the magnetic disc is disclosed in which, in order to improve the magnetic squareness of the thin magnetic film and to eliminate the nonuniformity thereof, a magnetic field formed between a pair of magnetic poles which have the same polarity and disposed so as to be symmetrical with respect to the magnetic disc, is first applied to both surfaces of the magnetic disc immediately after the thin magnetic film has been formed on the magnetic disc, and then magnetic fields from magnetic poles of different polarity are alternately applied to the magnetic disc. In a modified version of this method, particle orientation is performed in the following manner. That is, in a period when the magnetic film is not yet dried, a magnetic field formed between magnetic poles which have the same polarity and are symmetrical with respect to the magnetic disc, is first applied to the magnetic disc, and then magnetic fields from magnetic poles of different polarity are alternately applied to the magnetic disc. Further, after the thin magnetic film has been dried, a magnetic field formed between magnetic poles which have the same polarity and are symmetrical with respect to the magnetic disc, is again applied to the magnetic disc.