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:
Aug. 04, 2009
Filed:
Aug. 16, 2006
Toshihiro Sugaya, Moriya, JP;
Masato Otsuka, Tokyo, JP;
Naomasa Nakamura, Yokohama, JP;
Nobuhisa Yoshida, Kamakura, JP;
Hisashi Yamada, Yokohama, JP;
Toshihiro Sugaya, Moriya, JP;
Masato Otsuka, Tokyo, JP;
Naomasa Nakamura, Yokohama, JP;
Nobuhisa Yoshida, Kamakura, JP;
Hisashi Yamada, Yokohama, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Memory-Tech Corporation, Chikusei, JP;
Abstract
According to one embodiment, an optical disc is the following the distance between a light incidence plane and the first recording layer is a minimum of 550 μm. The distance between the first and the third recording layer is a maximum of 72 μm. The distance between the second and the third recording layer is a minimum of 15 μm. The distance between the first and the second recording layer is about 31 to 40 μm. The reflectivities of the first and the second recording layer with respect to the first laser beam range from 18 to 27%, and the ratio therebetween is about 1.1 or less. The reflectivity of the third recording layer is below about 6%. The areal recording density of the third recording layer is three times or more as high as that of the first recording layer and the second recording layer.