Patent ID: 8184509

Claim:
An optical pickup device comprising: a laser beam source; an object lens to focus a laser beam emitted from the laser beam source onto an optical disk; a beam divider to divide a signal beam reflected by the optical disk into a plurality of beams; and an optical detector having a plurality of light receiving areas which receive the divided signal beams respectively; wherein, of the signal beams divided by the beam divider, peripheral beams removed of a push-pull signal region are detected by the optical detector; wherein a detection signal from the peripheral beams is used to detect a differential phase detection (DPD) signal as a tracking error signal; wherein the beam divider has at least seven diffraction areas; wherein, of disk-diffracted beams diffracted by track grooves formed in a recording layer of the optical disk: 0-th order disk-diffracted light including a center of the beam enters into a first diffraction area, 0-th order and +1st order disk-diffracted light enter into a second diffraction area, 0-th order and −1st order disk-diffracted light enter into a third diffraction area, peripheral regions of the 0-th order disk-diffracted light beam enter into fourth and fifth diffraction areas adjoining the second diffraction area, peripheral regions of the 0-th order disk-diffracted light beam enter into sixth and seventh diffraction areas adjoining the third diffraction area, the fourth and the sixth diffraction area adjoin each other, and the fifth and the seventh diffraction area also adjoin each other; wherein a push-pull signal is detected from the 1st order light of whichever sign has a stronger light intensity in the second and third diffraction area of the beam divider; wherein a lens error signal proportional to a distance that the object lens has moved and the differential phase detection signal (DPD) are detected from the 1st order light of whichever sign has a stronger light intensity in the fourth to the seventh diffraction areas; wherein 1st order light with a sign of the stronger light intensity from the fourth to the seventh diffraction areas is detected at separate light receiving areas of the plurality of light receiving areas, and detection signals at said separate light receiving areas are output independently from the detection signals at other light receiving areas, respectively; and wherein a focus error signal is detected from the first order light of whichever sign has a weaker light intensity in the fourth to the seventh diffraction area.