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:
Apr. 24, 2007
Filed:
Apr. 14, 2004
Akihiko Seki, Tokyo, JP;
Takayoshi Kuwajima, Tokyo, JP;
Naoto Yajima, Tokyo, JP;
Hiroyuki Yamada, Tokyo, JP;
Kenichi Kitamura, Tokyo, JP;
Akihiko Seki, Tokyo, JP;
Takayoshi Kuwajima, Tokyo, JP;
Naoto Yajima, Tokyo, JP;
Hiroyuki Yamada, Tokyo, JP;
Kenichi Kitamura, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
The present invention provides a magnetic recording medium comprising a thin film magnetic layer of thickness in a range from 0.03 to 0.30 μm, and having excellent surface smoothness and superior electromagnetic conversion characteristics. The magnetic recording medium comprises a lower non-magnetic layer containing at least a non-magnetic powder and a binder resin on one surface of a non-magnetic support, an upper magnetic layer containing at least a ferromagnetic powder and a binder resin on the lower non-magnetic layer, and a back coat layer on the other surface of the non-magnetic support, wherein the thickness of the upper magnetic layer is within the range from 0.03 to 0.30 μm, the AFM surface roughness Ra of the upper magnetic layer is 6 nm or less, and the number of concavities with a depth of 30 nm or greater in the surface of the upper magnetic layer is 5 per 1 cmof surface area or less.