Patent ID: 8031575

Claim:
An optical pickup device comprising: a near-field optical system having a numerical aperture of NA>1; a first light source that emits light having a first wavelength and a second light source for emitting light having a second wavelength; an optical system that multiplexes the light having the first wavelength and the light having the second wavelength, and irradiates the multiplexed light onto an optical recording medium having at least two recording layers; a first photodetector that detects the light having the first wavelength returned from the optical recording medium and a second photodetector that detects the light having the second wavelength returned from the optical recording medium; a controller that obtains a signal corresponding to a variable distance between a lens-end-surface of the near-field optical system and a surface of the optical recording medium based on the light having the second wavelength returned from the optical recording medium, and obtains a reproducing signal of the optical recording medium, a tracking signal of the optical recording medium and a focus signal corresponding to each of the recording layers of the optical recording medium based on the light having the first wavelength returned from the optical recording medium; and a focus position adjustment mechanism arranged in an optical path of the light having the first wavelength that moves a focus position of the light having the first wavelength under control of the focus signal, the focus position being formed inside the optical recording medium.