Optical disc apparatus and spherical aberration correction controlling apparatus

An optical disc apparatus, comprising:

• an objective lens for focusing a light beam on an information surface of an optical disc, the optical disc being at least reproduced optically;
• an objective lens moving section for moving the objective lens in relation to the information surface;
• a focus control section for controlling the objective lens moving section to focus the light beam on the information surface;
• a light receiving section for receiving the light beam reflected from the optical disc;
• a lens tilting section for tilting the objective lens to correct coma aberration occurring in a light beam spot focused on the information surface, wherein the lens tilting section generates a tilt control signal based on the tilt of the objective lens;
• a lens tilt-spherical aberration correction amount determining section which generates a calibration signal for calibrating spherical aberration based on light detection occurring in the light beam spot focused on the information surface, wherein the lens tilt-spherical aberration correction amount determining section receives the tilt control signal and further generates a spherical aberration correction amount signal in the form of a predetermined relationship between the tilt control signal and a resultant lens tilt spherical aberration;
• a lens tilt-spherical aberration correction control section which receives the tilt control signal and the spherical aberration correction amount signal, and generates a spherical aberration correction signal based on the predetermined relationship between the tilt control signal and a resultant lens tilt spherical aberration;
• and
• a drive section for correcting spherical aberration that receives the spherical aberration correction signal to drive at least one spherical aberration correction lens.

A spherical aberration correction controlling apparatus for controlling a spherical aberration correcting section for correcting spherical aberration occurring in a light beam spot focused on an information surface of an optical disc by an objective lens, the apparatus comprising:

• a tilt control section for controlling a tilt of the objective lens to correct coma aberration occurring in the light beam spot focused on the information surface, wherein the tilt control section generates a tilt control signal based on the tilt of the objective lens;
• a spherical aberration signal generator for generating a first spherical aberration correction signal based on light detection occurring in the light beam spot focused on the information surface;
• a lens tilt-spherical aberration correction control section which receives the tilt control signal and the first spherical aberration correction signal, and generates a second spherical aberration correction signal by modifying the first spherical aberration correction signal by an amount based on a predetermined relationship between the tilt control signal and a resultant lens tilt spherical aberration;
• and
• a drive section for correcting spherical aberration that receives the second spherical aberration correction signal to drive at least one spherical aberration correction lens.