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. 13, 2004
Filed:
Jun. 13, 2001
Applicant:
Inventors:
Nobuhide Matsuda, Hirakata, JP;
Akira Saito, Kawasaki, JP;
Assignee:
Other;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 5/86 ;
U.S. Cl.
CPC ...
G11B 5/86 ;
Abstract
A positioning mark of a soft magnetic film is provided at the center of a master disk, and a beam from a light source irradiates the position of the mark. When a optical reception sensor using a CCD recognizes the mark, the recognizability of the positioning mark can be improved by using a wavelength selective filter or a laser as the light source. Additionally, the recognizability of the positioning mark can be improved by forming the positioning mark using a material other than a soft magnetic material.