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. 02, 2009
Filed:
Aug. 24, 2005
Motoyasu Terao, Hinode, JP;
Toshimasa Kamisada, Hiratsuka, JP;
Shinichi Nakatsuka, Hino, JP;
Takeshi Shimano, Yokohama, JP;
Hitoshi Ishii, Kaisei, JP;
Kazuhiro Soga, Odawara, JP;
Yoshiaki Ogino, Ninomiya, JP;
Motoyasu Terao, Hinode, JP;
Toshimasa Kamisada, Hiratsuka, JP;
Shinichi Nakatsuka, Hino, JP;
Takeshi Shimano, Yokohama, JP;
Hitoshi Ishii, Kaisei, JP;
Kazuhiro Soga, Odawara, JP;
Yoshiaki Ogino, Ninomiya, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi Computer Peripherals Co., Ltd, Kanagawa, JP;
Abstract
To achieve stable, high capacity, high speed recording. Of two light beams emitted from a light irradiation means, one or two beams are made pass through an optical path changeable member whereof at least one of the thickness and refractive index changes continuously or in two or more steps immediately after emission from the light irradiation means, so that a difference is introduced into the optical path length of the two beams, and the focusing point of one beam is made to vary to coincide with a position in the recording layer used for playback or recording. Another light beam is used for servo. Converging of light during recording or read of a multilayer recording medium is performed with higher precision than in the prior art, so higher density, higher capacity recording/playback can be performed.