Patent ID: 7729215

Claim:
An optical disc drive apparatus comprising: an optical pickup that moves along a transportation shaft provided along a radial direction of a rotatable optical disc and picks up reflected light after emitting an optical beam via an objective lens to a signal recording surface of the optical disc; a drive section that controls the objective lens to adjust an angle of the optical beam emitted to the optical disc; an angular velocity detection section that detects an angular velocity around the transportation shaft when an external force is applied; storage means for previously storing coefficients from which the degree of skew of the optical disc around a virtual axis perpendicular to the transportation shaft is calculated using the angular velocity, the skew of the optical disc arising from the external force; a skew estimation section that calculates a skew estimate value of the optical disc by multiplying the coefficient acquired from the storage means by the angular velocity detected by the angular velocity detection section; and a drive signal generation section that generates a drive signal based on the skew estimate value and supplies the drive signal to the drive section to adjust the angle of the emitted optical beam in accordance with the skew estimate value.