Invention Grant
- Patent Title: Optical head apparatus and optical information recording/reproducing apparatus
- Patent Title (中): 光头装置和光信息记录/重放装置
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Application No.: US12091799Application Date: 2006-10-27
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Publication No.: US07948854B2Publication Date: 2011-05-24
- Inventor: Ryuichi Katayama
- Applicant: Ryuichi Katayama
- Applicant Address: JP Tokyo
- Assignee: NEC Corporation
- Current Assignee: NEC Corporation
- Current Assignee Address: JP Tokyo
- Agency: Young & Thompson
- Priority: JP2005-314219 20051028; JP2006-277256 20061011
- International Application: PCT/JP2006/321489 WO 20061027
- International Announcement: WO2007/049738 WO 20070503
- Main IPC: G11B7/00
- IPC: G11B7/00

Abstract:
An optical head apparatus of an optical information recording/reproducing apparatus is provided with a light source. An objective lens focuses an output light emitted by said light source on a disc optical recording medium for which a groove or a pit for tracking is provided. T photo-detector receives a reflected light reflected by said optical recording medium. A polarizing splitter unit splits said output light and said reflected light. A quarter-wave plate disposed between said polarizing splitter section and said objective lens. A birefringence compensating unit reduces a change in an amplitude of a track error signal caused by birefringence in a protective layer of said optical recording medium.
Public/Granted literature
- US20090046548A1 OPTICAL HEAD APPARATUS AND OPTICAL INFORMATION RECORDING/REPRODUCING APPARATUS Public/Granted day:2009-02-19
Information query
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