Patent ID: 7778136

Claim:
An optical recording medium driving apparatus that records and/or plays back data on an optical recording medium having a plurality of recording layers, the apparatus comprising: head means for radiating laser light on the optical recording medium and detecting reflected light from the optical recording medium at least to read out a signal, the head means having at least a mechanism of focusing the laser light and a spherical aberration correction mechanism; focusing control means for driving the focusing mechanism based on the reflected light detected by the head means to perform focusing control on each recording layer of the plurality of recording layers on the optical recording medium; spherical aberration correcting means for driving the spherical aberration correction mechanism based on a spherical aberration correction value to correct spherical aberration; and control means for, when a condition for a focusing operation targeted for a target layer of the plurality of recording layers other than a first recording layer most proximal to a side on which the laser light is incident is satisfied, controlling the focusing control means so as to set the spherical aberration correction value given by shifting the spherical aberration correction value appropriate for a midpoint between the target layer and the first recording layer by a desired value in the spherical aberration correcting means and controlling the focusing control means so as to perform focusing control on the target layer with the spherical aberration correction value resulting from the shift being set.