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US 2010/0142354 A1Published application
Optical pickup device
AssigneeHitachi Media Electronics Co., Ltd.
InventorsShigeharu KIMURA, Harukazu MIYAMOTO
Life of this patent
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Abstract
In an optical pickup capable of removing inter-layer crosstalk, a dark line that may appear in a central portion of a beam is removed. Thereby, an error in a data signal is reduced. Reflected light from a multi-layer disc is split into two parallel bundles with a splitting optical system in a way that the light is split at a central line. Thereby, when reflected light from a target layer is focused, the reflected light is not influenced from an attenuation element provided on an optical axis.
Claims10
An optical pickup device comprising:
- a laser light source;
- an irradiated light focusing optical system for focusing laser light from the laser light source on a recording layer of a multi-layer optical information storage medium;
- and
- a detection optical system for detecting, among reflected light, light reflected from the recording layer of the multi-layer optical information storage medium, wherein
- the detection optical system includes:
- a splitting optical system for splitting the reflected light from the recording layer into parallel light bundles respectively located on two sides of an optical axis so that the light bundles thus split do not pass through the optical axis;
- a reflected light focusing lens for focusing the reflected light thus split by the splitting optical system;
- a reflection surface provided at a minimum spot position of the reflected light from the recording layer among the reflected light focused by the reflected light focusing lens;
- an attenuation element provided between the reflected light focusing lens and the reflection surface in such a way as to include the optical axis and used for attenuating the quantity of reflected light from an adjacent layer other than the recording layer;
- and
- a photodetector for detecting the reflected light, and
- the reflected light reflected by the reflection surface is detected on the photodetector.
9 more elements
An optical pickup device comprising:
- a laser light source;
- an irradiated light focusing optical system for focusing laser light from the laser light source on a recording layer of a multi-layer optical information storage medium;
- and
- a detection optical system for detecting, among reflected light, light reflected from the recording layer of the multi-layer optical information storage medium, wherein
- a beam splitter and an objective lens are provided in an optical path of the irradiated light focusing optical system,
- the irradiated light focusing optical system and the detection optical system share the beam splitter and the objective lens,
- the irradiated light focusing optical system allows the laser light from the laser light source to pass through the beam splitter as divergent light,
- the detection optical system includes:
- a splitting optical system for splitting the reflected light from the recording layer into light bundles respectively located on two sides of an optical axis so that the light bundles do not pass through the optical axis immediately after the splitting and gradually converge on the optical axis;
- a reflection surface provided at a minimum spot position of the reflected light from the recording layer among the reflected light having passed through the splitting optical system;
- an attenuation element provided between the splitting optical system and the reflection surface in such a way as to include the optical axis and used for attenuating the quantity of reflected light from an adjacent layer other than the recording layer;
- and
- a photodetector for detecting the reflected light, and
- the reflected light reflected by the reflection surface is detected on the photodetector.
11 more elements
Dependencies are inferred from the claim text.