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. 07, 1999
Filed:
Apr. 06, 1998
Applicant:
Inventor:
Masahiro Furuta, Tokyo, JP;
Assignee:
Nikon Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
3692751 ; 369 13 ; 3692752 ; 369288 ; 428 644 ; 4286 / ; 4286 / ;
Abstract
A magnetooptical disk includes a thermal diffusion layer to suppress thermal transmission between adjacent information tracks. The information tracks are formed within the magnetooptical disk along respective land portions or groove portions having a difference in grade. During recording and erasing of the magnetooptical disk, the land portions and groove portions may be changed with identical power levels. The thermal diffusion layer diffuses heat generated by irradiation of a laser beam. A protective layer is formed over the thermal diffusion layer and a recording layer which records various bits of information is formed over the protective layer.