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:
Oct. 23, 2007
Filed:
Apr. 26, 1995
Hisataka Sugiyama, Kodaira, JP;
Takeshi Maeda, Kokubunji, JP;
Kiyoshi Matsumoto, Kokubunji, JP;
Motoyasu Terao, Tokyo, JP;
Shigenori Okamine, Kodaira, JP;
Tetsuya Nishida, Hachioji, JP;
Harukazu Miyamoto, Kodaira, JP;
Hisataka Sugiyama, Kodaira, JP;
Takeshi Maeda, Kokubunji, JP;
Kiyoshi Matsumoto, Kokubunji, JP;
Motoyasu Terao, Tokyo, JP;
Shigenori Okamine, Kodaira, JP;
Tetsuya Nishida, Hachioji, JP;
Harukazu Miyamoto, Kodaira, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a three-dimensional recording and reproducing apparatus having a recording medium including a plurality of recording layers stacked on a substrate and an optical system for converging a light irradiated from the substrate side on each of the plurality of recording layers to three-dimensionally record and reproduce information, the following equation is satisfied:λ/4≦(1/8)(1/−1)where A light spot is focused on each layer of the multi-layer structured disc to record and reproduce highly reliable data in a high density.