Patent ID: 8107345

Claim:
An optical disk device capable of loading a plurality of different kind of optical disks for use with different laser wavelengths, comprising: a first laser source configured to emit laser light of a first wavelength, said first laser source suitable for operation with optical disks of a first kind; a second laser source configured to emit laser light of a second wavelength longer than said first wavelength, said second laser source suitable for operation with optical disks of second kind; a first objective lens arranged to receive laser light of said first wavelength from said first laser source; a second objective lens arranged to receive laser light of said second wavelength from said second laser source, the numerical aperture of said second objective lens being smaller than said first objective lens; an actuator to adjust said objective lens; a spherical aberration corrector to correct spherical aberration of an incident laser beam; and module for determining, for an optical disk loaded in the optical disk device, whether said loaded optical disk is an optical disk of the first kind or an optical disk of the second kind, wherein: said spherical aberration corrector is set to a state which is appropriate for an optical disk of the first kind, and said first objective lens is adjusted by said actuator to determine if said loaded optical disk is an optical disk of the first kind; and if said loaded optical is not an optical disk of first kind, then said objective lens is adjusted by said actuator to determine if said loaded optical disk is an optical disk of the second kind.