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:
Dec. 15, 1987
Filed:
Sep. 04, 1986
Kuniichi Yoda, Saku, JP;
Eiji Kitaura, Saku, JP;
Tsutomu Tsunoda, Saku, JP;
Yoshio Kawakami, Nagano, JP;
TDK Corporation, Tokyo, JP;
Abstract
A magnetic recording medium comprises a light-shielding base in the form of a tape or sheet, and a magnetic layer composed of a magnetic powder of Co-coated .gamma.-Fe.sub.2 O.sub.3 dispersed in a resin binder and applied to the base. The powder has a specific surface area as determined by the BET adsorption method of at least 35 m.sup.2 /g. The light-shielding base portion contiguous to the magnetic layer is a transparent plastic film and the lower base portion is light-shielding. The light-shielding base has a light transmittance of 30% or below. The surface roughness of the base is, in terms of the center-line average surface roughness, 0.012 .mu.m or below.