Invention Grant
- Patent Title: Optical head device and optical information recording or reproducing device
- Patent Title (中): 光头装置和光信息记录或再现装置
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Application No.: US11149130Application Date: 2005-06-10
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Publication No.: US07710849B2Publication Date: 2010-05-04
- Inventor: Ryuichi Katayama
- Applicant: Ryuichi Katayama
- Applicant Address: JP Tokyo
- Assignee: NEC Corporation
- Current Assignee: NEC Corporation
- Current Assignee Address: JP Tokyo
- Agency: Whitham Curtis Christofferson & Cook, PC
- Priority: JP2004-175374 20040614
- Main IPC: G11B7/00
- IPC: G11B7/00

Abstract:
Provided is an optical head device and an optical information recording or reproducing device for performing recording or reproduction to/from a plurality of types of optical recording medium, which can obtain a stable track error signal by a small size and exhibits high efficiency. Light PD and light PC emitted from a double-wavelength light source make incidence to a diffractive optical element in the same polarization directions. Diffraction gratings have a double refractive characteristic and in these areas the polarization directions of the two light beams become orthogonal. The light of 650 nm band is divided into 0th-order light and ±1st-order diffracted light in one of the diffraction grating and transmits through the other diffraction grating. The light of 780 nm band transmits through one of the diffraction grating and is divided into 0th-order light and ±1st-order diffracted light in the other diffraction grating. The two light beams are emitted from the diffractive optical element in the same polarization direction and guided towards the optical recording medium through a polarizing beam splitter and a quarter-wave plate.
Public/Granted literature
- US20050274870A1 Optical head device and optical information recording or reproducing device Public/Granted day:2005-12-15
Information query
IPC分类: