Patent ID: 8331207

Claim:
An optical pickup configured to accept a multi-layer optical disc, comprising: a laser source for emitting an optical beam, an objective lens for focusing the light beam onto the multi-layer optical disc, a polarizing grating located at a position through which a reflected light beam from the multi-layer optical disc passes, for branching the reflected beam into at least two light beams comprising a 0-order light beam and a +1-order light beam having a direction of polarization which is orthogonal to that of the 0-order light beam, an optical detector for receiving the two light beams, a first light receiving zone which is provided in the optical detector, and onto which the 0-order light is irradiated, and, a second light receiving zone which is provided in the optical detector and onto which the +1-order light beam is irradiated, wherein the first light receiving zone has four zones, and the second light receiving zone has two zones, and a servo signal generation circuit configured to generate a push-pull signal by taking a difference between a sum signal of signals from two zones of the four zones and a sum signal of signals from the other two zones of the four zones, to generate an offset signal having substantially no push-pull signal components by taking a difference between a signal from one of the two zones of the second light receiving zone and a signal from another zone of the two zones of the second light receiving zone, to obtain a focus error signal by using signals from the first light receiving zone, and to obtain a tracking error signal by taking a difference between the push-pull signal and the offset signal.