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:
May. 25, 1999
Filed:
Apr. 25, 1996
Kazunobu Chiba, Miyagi, JP;
Kenichi Sato, Miyagi, JP;
Yuichi Arisaka, Miyagi, JP;
Yukari Yamada, Miyagi, JP;
Sony Corporation, Tokyo, JP;
Abstract
A magnetic recording medium, comprising a nonmagnetic substrate on the surface of which is deposited a magnetic layer. In one embodiment, the magnetic layer is formed of two thin films of magnetic metal and a layer of nonmagnetic material sandwiched therebetween, the layer of nonmagnetic material having a thickness no greater than 20% of the thickness of the magnetic layer, with the magnetic layer having an energy product of at least 100 gauss.multidot.cm.multidot.Oe as the product of its residual magnetic flux density, thickness and coercive force, and a surface roughness no greater than 0.003 .mu.m in center line average height. In another embodiment, the magnetic layer, which may be a single layer of magnetic metal film or may be of the aforementioned multiple layer construction, is vacuum deposited onto the substrate at an incident angle in the range of 30.degree. to 70.degree..