Servo control apparatus for optical disc driver

A servo control apparatus for an optical disc driver, in which a control signal assigned to a displacement amount of an optical beam from a target value is used to drive an actuator for controlling a position of the optical beam on an optical disc, comprising:

• a defect detecting device for detecting a defect on the basis of reflected light of the optical beam from the optical disc;
• a storing device for storing sample data of the control signal obtained during a predetermined interval corresponding to a detection delay of the defect due to at least the defect detecting device on the basis of sample values of the control signal inputted at predetermined sampling intervals;
• a cancel signal producing device for producing a cancel signal to cancel influences of the control signal obtained during the predetermined interval on the basis of the stored sample data;
• and
• an outputting device for outputting the cancel signal as the control signal immediately after the detection of the defect.