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. 10, 2005
Filed:
Jul. 10, 2003
Takashi Yumiba, Kyoto, JP;
Teruyuki Takizawa, Osaka, JP;
Mitsuro Moriya, Nara, JP;
Mitsuaki Oshima, Kyoto, JP;
Akihiko Nishioka, Osaka, JP;
Koichi Morioka, Osaka, JP;
Takashi Yumiba, Kyoto, JP;
Teruyuki Takizawa, Osaka, JP;
Mitsuro Moriya, Nara, JP;
Mitsuaki Oshima, Kyoto, JP;
Akihiko Nishioka, Osaka, JP;
Koichi Morioka, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical disk is provided for recording data of a signal modulated according to a predetermined modulation method in a form of concavo-convex pits. The optical disk includes a first area having a reflecting film partly removed, and a second area for recording pits which are different from pits satisfying requirements of the predetermined modulation method. The first area having the reflecting film partly removed includes a portion which is formed by removing the reflecting film, and has a length longer than a maximum pit length determined by the modulation method in a circumferential direction of the optical disk. When the pits recorded on the optical disk are physically copied as they are, physical copying of the optical disk can be prevented by utilizing such a difference that the authorized optical disk differs from a pirated copy in a combination of the respective reproduced signals of the first and second areas.