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US 2009/0154326 A1Published application
Optical recording and reading equipment
AssigneeHitachi, Ltd.
InventorsKoichi Watanabe, Takahiro Kurokawa, Masahiro Aoki, Takeshi Shimano
Life of this patent
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Abstract
Disclosed herewith is a data recording and reading equipment capable of reducing laser noise easily. At first, a laser beam source that can reduce the laser noise when reading data from a subject optical disk is obtained. A modulator capable of varying laser attenuation with a voltage is disposed so as to precede the laser, thereby the laser noise when reading data from the optical disk can be reduced without lowering the laser power when in writing.
Claims6
A data recording and reading equipment, including:
- a laser for emitting a beam, the beam being radiated onto a data recording medium;
- a modulator that changes a degree of attenuation of the beam emitted by the laser in accordance with a control voltage applied to the modulator;
- a photo-current monitor that detects a photo-current generated at the modulator,
- wherein the degree of attenuation is controlled by using an output signal of the photo-current monitor.
1 more element
A data recording and reading equipment, including:
- a laser for emitting a beam, the beam being radiated onto a data recording medium;
- a modulator that changes a degree of attenuation of the beam emitted from the laser in accordance with a control voltage applied to the modulator;
- a photo-current monitor that detects a photo-current generated at the modulator,
- wherein power of the laser is controller by using an output signal of the photo-current monitor.
1 more element
Dependencies are inferred from the claim text.