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:
Jun. 02, 1998
Filed:
Aug. 27, 1996
Applicant:
Inventors:
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
3692751 ; 369 94 ;
Abstract
The present invention provides a multi-layer optical disk, in which even if a wave length of read light is changed at a time of reproducing, both of reproduction signals from a first information memory layer and a second information memory layer have sufficient levels. In a multi-layer optical disk, in which a first information memory layer and a second information memory layer are sequentially film-formed on a substrate and information recorded on the first information memory layer and the second information memory layer are reproduced by irradiating read light from a substrate side,