Patent ID: 8130602

Claim:
An optical disk drive, comprising: an objective lens for applying a beam from a laser to an optical disk; an actuator for driving the objective lens to cause a focal point of the beam applied to the optical disk to move in a focus direction; an optical sensor for detecting the beam reflected from the optical disk and outputting the beam as a detection signal; a generation unit for driving the actuator to output a shift in the focal point of the beam from the detection signal output from the optical sensor as a focus error signal; and a servo controller that receives an input of the focus error signal from the generation unit, for driving the actuator to control a focusing position of the beam, the servo controller comprising: a compensation unit for generating a drive signal for the actuator based on the focus error signal; a noise detection unit that receives an input of the drive signal output from the compensation unit, for detecting a noise component by changing a limiter characteristic according to a frequency of the drive signal; and a correction unit for correcting the drive signal by subtracting the noise component detected by the noise detection unit from the drive signal output from the compensation unit.