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:
Jul. 04, 2006
Filed:
Sep. 24, 2003
Junsaku Nakajima, Kashihara, JP;
Hitoshi Takeuchi, Kitakatsuragi-gun, JP;
Masaru Nomura, Nabari, JP;
Junsaku Nakajima, Kashihara, JP;
Hitoshi Takeuchi, Kitakatsuragi-gun, JP;
Masaru Nomura, Nabari, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
On an optical disc including a substrate on which pits having at least two different depths are formed, main information is recorded by the shape of the pits and additional information is recorded by the depth of the pit. It is possible to reverse polarity of a tangential push-pull signal dependent on the depth of the pit, and therefore it becomes possible to record information utilizing the depth of the pit. This improves recording density of the optical disc. Further, when information of the optical disc is to be copied, the information recorded by the depth of the pit cannot be copied. Therefore, unauthorized reproduction can be prevented.