LIGHT RECEIVING UNIT, OPTICAL PICKUP EQUIPPED WITH THIS LIGHT RECEIVING UNIT AND OPTICAL REPRODUCING DEVICE, OPTICAL RECORDING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical pickup enabling recording or reproduction to a plurality of optical recording media whose track shape and track pitch differ. SOLUTION: The optical pickup has a hologram optical element 23 which divides a laser beam into three beams of a main beam, a preceiding sub-beam, and a succeeding sub-beam, for irradiating an optical recording medium 4, and divides into four more beams each of a return light beam reflected by the optical recording medium concerned. Each divided beam is received by a light receiving unit 10 having a first to fourth main light receiving elements, a first to fourth preceding sub-light receiving elements and a first to fourth succeeding sub-light receiving elements. A tracking servo to the optical recording medium 4 concerned is performed exactly by selecting a tracking error signal most suitable for the kind of an optical disk to be reproduced among three kinds of tracking error signals detected by the combination of the detecting signal of these light receiving elements.