Patent ID: 7145842

Claim:
An objective lens moving control method for controlling the movement of an objective lens in its focusing direction on the basis of focus error signal corresponding to a focusing shift of the objective lens from a recording layer of a multilayer recording optical disk, the merhud comprising the steps of: detecting a changing request of a recording layer to be converged by the laser beam emitted from the objective lens; starting the approach of the objective lens so the recording layer to be converged by a laser beam; determining a time T in accordance with a moving speed of said objective lens; calculating a masking time based on the time T; not starting braking of said objective lens by masking signals indicating that an absolute value of a focus error signal exceeds a predetermined second reference level during the masking time from a time point at which the absolute value of the focus error signal becomes lower than a predetermined first reference level for a first time after exceeding the first reference level, and starting braking of the objective lens when the absolute value of the focus error signal exceeds the second reference value after the masking time has passed.