Optical medium reproducing apparatus and optical medium reproducing method
AssigneeSony Corporation
InventorsKenji Yamamoto, Takashi Nakao, Kimihiro Saito
Life of this patent
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Abstract
An optical medium reproducing apparatus that optically reproduces an optical medium on which a plurality of tracks is formed in which a beam returning from the optical medium is divided into a first region of an outside portion and a second region of an inside region, according to the shape of the pupil of an object lens, and crosstalk between the tracks is reduced by using a first detection signal of the first region and a second detection signal of the second region.
Claims28
An optical medium reproducing apparatus that optically reproduces an optical medium on which a plurality of tracks is formed, comprising:
- a single beam having a beam diameter and returning from the optical medium, and
- a detector, wherein:
- the single beam is divided into a first region and a second region, the second region corresponding to a center portion of the beam diameter, and the first region corresponding to a portion of the beam diameter outside the center portion,
- the detector generates a first detection signal corresponding to the first region and a second detection signal corresponding to the second region, and
- crosstalk between the tracks is reduced using only information from the single beam by subtracting the second detection signal from the first detection signal.
An optical medium reproducing method that optically reproduces an optical medium on which a plurality of tracks is formed, the method comprising:
- dividing a single beam having a beam diameter and returning from the optical medium into a first region and a second region, the second region corresponding to a center portion of the beam diameter, and the first region corresponding to a portion of the beam diameter outside the center portion;
- obtaining a first detection signal based on an amount of light received by a first region of a detector, the first region of the detector corresponding to the first region of the beam diameter;
- obtaining a second detection signal based on an amount of light received by a second region of the detector, the second region of the detector corresponding to the second region of the beam diameter;
- and
- reducing crosstalk between the tracks using only information from the single beam by subtracting the second detection signal from the first detection signal, wherein:
- a shape of the beam is formed according to a shape of a pupil of an object lens.
An optical medium reproducing method that optically reproduces an optical medium on which a plurality of tracks is formed, the method comprising:
- dividing a single beam having a beam diameter and returning from the optical medium into a first region and a second region, the second region corresponding to a center portion of the beam diameter, and the first region corresponding to a portion of the beam diameter outside the center portion;
- obtaining a first detection signal based on an amount of light received by a first region of a detector, the first region of the detector corresponding to the first region of the beam diameter;
- obtaining a second detection signal based on an amount of light received by a second region of the detector, the second region of the detector corresponding to the second region of the beam diameter;
- and
- reducing crosstalk between the tracks using only information from the single beam by blocking the center portion of the beam diameter and subtracting the second detection signal from the first detection signal, wherein:
- a shape of the beam is formed according to a shape of a pupil of an object lens.
Dependencies are inferred from the claim text.