Invention Grant
- Patent Title: Optical information recording and/or reproducing apparatus, optical information recording and/or reproducing method, optical information recording medium, and solid immersion lens
- Patent Title (中): 光学信息记录和/或再现装置,光学信息记录和/或再现方法,光学信息记录介质和固体浸没透镜
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Application No.: US12993599Application Date: 2009-05-18
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Publication No.: US08130623B2Publication Date: 2012-03-06
- Inventor: Kenji Narumi , Masahiro Birukawa , Rie Kojima , Eiichi Ito
- Applicant: Kenji Narumi , Masahiro Birukawa , Rie Kojima , Eiichi Ito
- Applicant Address: JP Osaka
- Assignee: Panasonic Corporation
- Current Assignee: Panasonic Corporation
- Current Assignee Address: JP Osaka
- Agency: Wenderoth, Lind & Ponack, L.L.P.
- Priority: JP2008-135130 20080523
- International Application: PCT/JP2009/002180 WO 20090518
- International Announcement: WO2009/141994 WO 20091126
- Main IPC: G11B7/135
- IPC: G11B7/135

Abstract:
An optical information recording and/or reproducing apparatus comprises: a focusing unit (11) which collects generated near-field light on an optical disc (1); a first detector (17) which receives light reflected by the optical disc (1) and outputs an electric signal according to the quantity of the received light; and a distance control circuit (22) which controls the distance between the focusing unit (11) and a light entrance surface of the optical disc (1), using the electric signal that is output from the first detector (17), and the optical disc (1) has at least N (N is an integer of 2 or greater) number of information layers, and a distance d0 from the light entrance surface to a first information layer which is most distant from the light entrance surface and a distance dn from the light entrance surface to an Nth information layer which is closest to the light entrance surface satisfy the relationship of dn≧d0×(1/25). As a result, servo control can be accurately performed regardless which information layer, out of a plurality of information layers of an optical disc, information is recorded to or reproduced from.
Public/Granted literature
Information query
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