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:
Apr. 12, 2011
Filed:
Feb. 07, 2006
Goro Fujita, Kanagawa, JP;
Takashi Shimouma, Kanagawa, JP;
Jun Nakano, Tokyo, JP;
Shigeki Takagawa, Kanagawa, JP;
Kimihiro Saito, Saitama, JP;
Goro Fujita, Kanagawa, JP;
Takashi Shimouma, Kanagawa, JP;
Jun Nakano, Tokyo, JP;
Shigeki Takagawa, Kanagawa, JP;
Kimihiro Saito, Saitama, JP;
Sony Corporation, Tokyo, JP;
Abstract
In an optical disk, a substrate has main data recorded in the form of a combination of pits and lands on one side thereof, and at least a reflective layer and cover layer are stacked on the substrate to cover the pits and lands on the substrate. To the optical disk, sub data is recorded in the form of marks formed by irradiating writing-power laser light to the reflective layer. The marks are formed so that reading signal level will be raised where the marks are formed while it will be lowered where the marks are formed in a counterfeit disk produced based on an authenticated disk, namely, the reading signal level where the marks are formed is different in polarity between in the authenticated and counterfeit disks. Further, in a player for the optical disk, discrimination is made between the authenticated and counterfeit disks by detecting the sub data recorded in the optical disk and judging whether the value of the detected sub data has been read at a correct polarity.