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:
Oct. 16, 2001
Filed:
May. 18, 1999
Hideaki Tanaka, Katsuta, JP;
Kenichi Gomi, Hitachi, JP;
Yoshihiko Miyake, Odawara, JP;
Sigeru Sano, Fuji, JP;
Youichi Inomata, Odawara, JP;
Hiroshi Yashiki, Odawara, JP;
Yoshiki Kato, Tokyo, JP;
Masaki Ohura, Odawara, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A magnetic disk includes a substrate, a magnetic layer, and a protective layer. At least one region of a surface of the magnetic disk has protrusions. A height of each of the protrusions is not less than 5 nm and not greater than 40 nm, and is within ±30% of an average height of the protrusions. A density of the protrusions is not less than 200/mm,and is not greater than 250,000/mm,. A width of a surface of each of the protrusions in a radial direction of the magnetic disk is not less than 0.1 &mgr;m and is not greater than 10 &mgr;m. The protrusions are discrete protrusions aligned in a spiral direction of the magnetic disk at a predetermined spacing in the radial direction of the magnetic disk. The at least one region of the surface of the magnetic disk includes flat areas between the protrusions. At least some of the flat areas extend continuously from an inner redius of the at least one region of the surface of the magnetic disk to an outer radius of t he at least one region of the surface of the magnetic disk.