Optical disk pickup device with tilt compensation by electrostriction

An optical pickup for recording information on a recording surface of an optical disc and/or reproducing information from the recording surface of the optical disc, the optical pickup comprising:

• a light source means for radiating an outgoing light beam on the optical disc;
• an object lens means for converging the outgoing light beam on the recording surface of the optical disc;
• a piezoelectric plate disposed in the path of the outgoing light beam, having a first surface and a second surface, the piezoelectric plate transmitting the outgoing light beam, with the thickness of the piezoelectric plate between the first surface and the second surface varying with voltage applied across the piezoelectric plate;
• at least one transparent first-surface electrode disposed on the first surface of the piezoelectric plate;
• a plurality of transparent second-surface electrodes disposed on the second surface of the piezoelectric plate, whereby the thickness of a portion of the piezoelectric plate in the vicinity of each second-surface electrode will depend on a voltage difference between the second-surface electrode and the first-surface electrode;
• and
• voltage means for applying a plurality of applied voltages respectively to the first-surface electrode and each of the second-surface electrodes to control the thickness of the piezoelectric plate, so that the outgoing light beam is corrected for coma aberrations on the information recording surface.