Patent ID: 8310910

Claim:
An optical pickup device comprising: a first light source for emitting laser light for BD; a second light source for emitting laser light for CD; an objective lens portion for converging the laser light for BD and the laser light for CD on BD and CD, respectively; a photodetector for receiving the laser light for BD reflected on the BD and the laser light for CD reflected on the CD; and an optical system for guiding the laser light for BD emitted from the first light source and the laser light for CD emitted from the second light source to the objective lens portion, and for guiding the laser light for BD reflected on the BD and the laser light for CD reflected on the CD to the photodetector, wherein the optical system includes: an astigmatism element for imparting astigmatism to the laser light for BD reflected on the BD and the laser light for CD reflected on the CD; and a spectral element for dispersing four light fluxes of the laser light for BD by diffraction, and for dispersing four light fluxes of the laser light for CD by diffraction, the four light fluxes of the laser light for BD and the four light fluxes of the laser light for CD being obtained by dividing the laser light for BD reflected on the BD and the laser light for CD reflected on the CD by a first straight line parallel to a converging direction by the astigmatism element, and a second straight line perpendicular to the first straight line, and the photodetector is provided with: a first sensor group for receiving the four light fluxes of the laser light for BD dispersed by the spectral element to generate a reproduction signal, and a servo signal for use in controlling the objective lens portion; and a second sensor group for receiving the four light fluxes of the laser light for CD dispersed by the spectral element to generate a reproduction signal, and a servo signal for use in controlling the objective lens portion.