Patent ID: 8279723

Claim:
An optical pickup device for irradiating laser light on a recording medium, the recording medium including at least one recording layer on which information is recorded by multi-photon absorption, and a servo layer disposed in a laminated direction with respect to the recording layer and having a track for guiding a beam spot of laser light having a first wavelength and a beam spot of laser light having a second wavelength along a scanning trajectory, the servo layer and the at least one recording layer constituting a set of layers, and a plurality of sets of layers being formed in the laminated direction, and the servo layer being made of a material having a high reflectance with respect to laser light having a third wavelength for generating a servo signal, and low reflectances with respect to the laser light having the first wavelength and the laser light having the second wavelength, the optical pickup device comprising: a first light source for emitting the laser light having the first wavelength; a second light source for emitting the laser light having the second wavelength; a third light source for emitting the laser light having the third wavelength; a recording/reproducing objective lens for converging the laser light having the first wavelength and the laser light having the second wavelength on the recording medium; a servo objective lens different from the recording/reproducing objective lens for converging the laser light having the third wavelength on the recording medium; a recording/reproducing optical system for guiding only the laser light having the first wavelength and the laser light having the second wavelength to the recording/reproducing objective lens by combining an optical path of the laser light having the first wavelength and an optical path of the laser light having the second wavelength, and guiding at least reflection light for reproducing, out of reflection light of the laser light having the first wavelength and the laser light having the second wavelength from the recording medium, to a reproducing photodetector; a servo optical system for guiding only the laser light having the third wavelength to the servo objective lens, and guiding reflection light of the laser light having the third wavelength from the recording medium to a servo photodetector; and a focus adjusting unit for displacing a focus position of the laser light having the third wavelength in an optical axis direction of the laser light having the third wavelength, and focus positions of the laser light having the first wavelength and the laser light having the second wavelength in optical axis directions of the laser light having the first wavelength and the laser light having the second wavelength.