Optical pickup
AssigneeHitachi Media Electronics Co., Ltd.
InventorsHiromi Kita, Tomoto Kawamura, Toshiteru Nakamura
Life of this patent
Estimating the term…
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AssigneeHitachi Media Electronics Co., Ltd.
InventorsHiromi Kita, Tomoto Kawamura, Toshiteru Nakamura
Estimating the term…
An optical pickup includes a light source, an objective lens, a diffraction grating that divides an optical beam reflected from a predetermined information layer, into a plurality of optical beams, and a detector having a plurality of photo-receivers to receive a plurality of optical beams. The diffraction grating has a predetermined region for dividing from a signal light beam a region including a central portion of a spot which the signal light beam will form on the diffraction grating. A distance from a central section of the detector to that of a spot center photo-receiver on the detector, the spot center photo-receiver being provided to receive the optical beams formed by division in a predetermined region of the diffraction grating, is equal to or greater than a spot radius of the unwanted light beams entering the predetermined region of the diffraction grating, on the detector.
An optical pickup that reproduces information from an optical disc having at least two information layers, the optical pickup comprising:
Dependencies are inferred from the claim text.