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:
Jun. 24, 2003
Filed:
Apr. 12, 2001
Mitsuaki Oshima, Kyoto, JP;
Shinichi Konishi, Nara, JP;
Shin-ichi Tanaka, Kyotanabe, JP;
Kenji Koishi, Sanda, JP;
Mitsurou Moriya, Ikoma, JP;
Yoshiho Gotoh, Osaka, JP;
Yoshinari Takemura, Settsu, JP;
Norio Miyatake, Kobe, JP;
Motoyoshi Murakami, Hirakata, JP;
Matsushita Electric Industrial Co., Ltd., Kadoma, JP;
Abstract
A method for reproducing write-once information from an optical disk. The disk includes a disk substrate and a recording layer on the disk substrate, the recording layer including a magnetic film with a magnetic anisotropy in a direction perpendicular to a surface of the magnetic film. Write-once information formed by first recording areas and second recording areas is stored in a pre-determined portion of said recording layer, the first and second recording areas having different magnetic anisotropies in a direction perpendicular to a surface of the magnetic film. The method includes irradiating linearly polarized laser light onto said pre-determined portion, and detecting a rotational change in a polarization orientation of light reflected from the optical disk or light transmitted through the optical disk, the rotational change being caused depending on which of the first recording area and the second recording area is irradiated with the linearly polarized laser light.