Patent ID: 7974167

Claim:
An optical disc apparatus, comprising: an optical head device comprising an objective lens and an objective lens actuator for moving the objective lens at least in a vertical direction to an optical disc, and configured to converge and apply a light beam to the optical disc via the objective lens by moving the objective lens; a focus error detection circuit configured to generate a focus error signal in accordance with positional displacement of a focus of the light beam with respect to a light incidence surface of the optical disc or an information recording surface of the optical disc; a focus control circuit configured to control the objective lens actuator based upon the focus error signal generated by the focus error detection circuit to allow the focus position of the light beam to follow the light incidence surface or the information recording surface; a surface-wobble-following signal storage device configured to store a surface-wobble-following signal as a driving signal that is applied to the objective lens actuator when the focus position is allowed to follow the light incidence surface of the optical disc; a focus-search-driving signal generation circuit configured to generate a focus-search-driving signal as a driving signal for changing the focus position of the light beam with respect to the optical disc; a superimposition signal generation circuit configured to generate a signal superimposed with the surface-wobble-following signal stored in the surface-wobble-following signal storage device and the focus-search-driving signal generated by the focus-search-driving signal generation circuit; and a focusing control circuit configured to control the objective lens actuator based upon the superimposition signal generated by the superimposition signal generation circuit and achieve a focus on the information recording surface of the optical disc in a state that the focus control circuit achieves a focus servo on the light incidence surface of the optical disc and the surface-wobble-following signal storage device stores the surface-wobble-following signal.