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:
Mar. 22, 1994
Filed:
Jan. 04, 1993
Seiji Yonezawa, Hachioji, JP;
Keiji Kataoka, Kawagoe, JP;
Hajime Fukke, Tama, JP;
Tsuneo Terasawa, Hachioji, JP;
Keizo Kato, Hachioji, JP;
Harukazu Miyamoto, Kodaira, JP;
Klaus Kinstatter, Bamberg, DE;
Masaru Ito, Sagamihara, JP;
Norio Ohta, Iruma, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The present invention uses a magnetic recording medium equipped with those magnetically readable recording servo pits which are preformed on a magnetic recording medium and have different magnetic characteristics from those of a recording magnetic film, detects magnetically a tracking signal or preformat signals such as sync signals, address signals, and the like, from the magnetic flux distribution (leakage magnetic field) occurring at edges of each of the servo pits using a magnetic head, makes servo control of the position of the magnetic head by the detected tracking signal and records or reads magnetically the data along the center of a track. In the magnetic recording medium of the present invention, magnetically readable, wobbled servo pits or sync pits, track address pits and data pits are preformed on the magnetic recording medium, these pit portions have locally different magnetic characteristics from those of the recording magnetic film and have a magnetic film structure wherein saturated magnetization is smaller than at other portions or the magnetic film is removed locally. These preformed pits can be read magnetically by detecting the local magnetic field (leakage magnetic field) generated at their edges by the magnetic head.