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. 26, 1989
Filed:
Mar. 31, 1988
Applicant:
Inventor:
Junichi Ichihara, Yokohama, JP;
Assignee:
Fujitsu Limited, Kawasaki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ; G11B / ;
U.S. Cl.
CPC ...
360114 ; 369 13 ;
Abstract
An electromagnetic bias coil for applying a magnetic bias field to a recording bit of a magneto-optical recording disk apparatus includes a yoke made of soft magnetic material, such as soft iron. The yoke surrounds an outer perimeter surface and a bottom surface of the coil. A light beam and optical system are arranged in an opening in the yoke. The yoke reduces the magnetic resistance of the coil, increases the magnetic field intensity at the recording bit, and reduces the current needed to achieve an adequate magnetic field intensity. The operating temperature of the coil is therefore improved.