Patent Document ID: 20020181350
Application ID: 10062834
Patent Flag: 0

Claim One:
1. A track servo control method for following an optical beam to a track of an optical storage medium that is formed tracks comprised of a plurality of sectors having ID parts shaped as a relief structure, comprising: a step of observing a positional error of the optical beam from said track by a reflected light from said optical storage medium; a step of controlling an actuator for moving said optical beam by a feedback control system according to said observed positional error; a step of inputting a signal based on said observed positional error and learning a signal waveform synchronizing with the period of said ID parts; and a step of inputting said learning result to said feedback control system and controlling the vibration of said actuator by periodic noise synchronizing with the period of said ID parts, wherein said learning step comprises a step of subtracting the learning result from the learning input and learning the learning signal after subtraction.