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:
May. 26, 1998
Filed:
Mar. 08, 1996
Applicant:
Inventors:
Tetsu Watanabe, Tokyo, JP;
Yoshio Aoki, Tokyo, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 13 ; 3692755 ;
Abstract
A magneto-optical disc system includes a magneto-optical disc 40 with a light-transmitting cover layer 41, an objective lens 2 for bundling or focusing a laser beam onto a magnetic recording layer 43 of the magneto-optical disc 40 for recording information thereon and/or reproducing information therefrom, and a magnetic field generating unit 9 having a coil pattern 7 arranged on an optical glass element 8. The thickness t.sub.2 of the light-transmitting cover layer 41 falls within the range of 0.6 to 0.1 mm, and the numerical aperture (NA) of the objective lens 2 falls within the range of 0.55 to 0.70.