Patent ID: 7903507
Filing Date: 2011-03-08
Classification: G11B

Abstract:
1. An optical pickup device, comprising: a semiconductor laser; a first objective lens that converges laser light outputted from the semiconductor laser on to a disk, and that is disposed at a position away from a diameter L of the disk by a distance z on a plane parallel to a surface of the disk, the diameter L being parallel to a moving direction of said optical pickup device; a photodetector that receives the laser light reflected from the disk, and that includes a sensor pattern divided into four regions by two parting lines orthogonally intersecting to each other; and an optical member in a plate shape that reflects the laser light outputted from the semiconductor laser to direct the laser light toward the first objective lens, and that transmits the laser light reflected from the disk to direct the laser light toward the photodetector, the optical member providing the reflected laser light with astigmatism so as to propagate in two planes, wherein in a case in which an oscillation angle a is formed in the plane parallel to the disk surface by the meeting of an optical axis of the laser light reflected by the optical member and directed toward the first objective lens with a line orthogonal to the disk diameter L and parallel to the disk surface, the oscillation angle a and the distance z are adjusted so that a track direction of the disk on the photodetector is positioned at substantially 45° to a cross-section of one plane of the reflected laser light, and one of the two parting lines of the sensor pattern is aligned with a line positioned at substantially 45° to the cross-section of the one plane of the reflected laser light.