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. 21, 1993
Filed:
Sep. 13, 1991
Applicant:
Inventors:
Shyuichi Kojima, Odawara, JP;
Hiroyuki Suzuki, Odawara, JP;
Akira Kato, Odawara, JP;
Keigo Iechika, Odawara, JP;
Mikio Takada, Kanagawa, JP;
Masaki Ohura, Odawara, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
360 9801 ; 360 9802 ; 360 9808 ;
Abstract
A disk-type recording medium having a circular substrate on which a recording layer is formed does not include any through hole formed in the center of rotation. Since no through hole is formed, it is possible to improve the reliability of the medium with regard to its strength, and to reduce the thickness of the substrate. Further, it is possible to render the thickness of the recording coating uniform.