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:
Mar. 10, 1998
Filed:
Mar. 14, 1995
Applicant:
Inventors:
Assignee:
Sony Corporation, , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ; G11B / ;
U.S. Cl.
CPC ...
3692752 ; 369 94 ;
Abstract
A novel multi-layer optical disc according to the present invention can treat a large volume of information without deterioration in level of reproduction signals from the respective information storage layers thereof. The multi-layer optical disc comprises a substrate having a light-transmission property, a read-only-memory type information storage portion formed on the substrate, a semi-transmission layer disposed on the read-only-memory type information storage portion, a spacer layer disposed on the semi-transmission layer and having a light-transmission property, and a rewritable information storage layer disposed on said spacer layer.