Patent ID: 8054733

Claim:
An optical pickup device for recording and/or reproducing information with respect to a disc having recording layers in a laminated direction, the optical pickup device comprising: a laser light source; an objective lens for conversing laser light emitted from the laser light source onto the disc; an astigmatism element for conversing the laser light reflected on the disc in a first direction to form a first focal line at a first position, and conversing the laser light in a second direction to form a second focal line at a second position closer to the disc than the first position; a polarization setting element for making polarization directions of light flux portions different from each other, the light flux portions being obtained by dividing a light flux of the laser light transmitted through the astigmatism element into two by a straight line parallel to the first direction; a polarizer for receiving the laser light transmitted through the polarization setting element, and which allowing light to transmit therethrough, the light having polarization directions obtained by inverting the polarization directions set by the polarization setting element with respect to the straight line; and a photodetector for receiving the laser light transmitted through the polarizer, wherein the polarization setting element is disposed between the second focal line of the laser light reflected on a targeted recording layer of the disc, and the first focal line of the laser light reflected on a recording layer farther than the target recording layer, and the polarizer is disposed between the first focal line and the second focal line of the laser light reflected on the targeted recording layer.