Patent ID: 8345528

Claim:
An optical pickup device comprising: a laser light source which emits laser light of a predetermined wavelength; an objective lens portion which converges the laser light at a first focal point and a second focal point; an actuator which positions the first focal point or the second focal point on a recording layer in a disc; an astigmatism element which imparts astigmatism to the laser light reflected on the disc to set a first focal line position to be defined by convergence of the laser light in a first direction, and a second focal line position to be defined by convergence of the laser light in a second direction perpendicular to the first direction away from each other in a propagating direction of the laser light; a spectral element which makes propagating directions of four light fluxes obtained by dividing a light flux of the laser light reflected on the disc in four by a first straight line and a second straight line respectively in parallel to the first direction and the second direction different from each other to disperse the four light fluxes from each other; and a photodetector having a sensor group which receives the four light fluxes dispersed by the spectral element.