Tracking servo and method for tracking optical disc and optical disc device using the tracking servo

A tracking method executed by an optical disc device, the optical disc device comprising an optical head for emitting light to read or write data from or to an optical disc, the tracking method comprising:

• providing a table for listing a plurality of predetermined track classes, and a plurality of tracking errors;
• calculating the number of tracks between a current track at which the optical head is currently positioned and a target track from or to which the optical head reads or writes data;
• determining whether the number of tracks reaches a predetermined number;
• searching for the table for the corresponding tracking error when the number of tracking error reaches a predetermined number;
• calculating second jumping tracks based on the first jumping tracks and the found tracking errors;
• and
• driving the optical head to move to the second jumping tracks for tracking.

An optical disc device comprising:

• an optical head emitting lights for reading or writing data from or to an optical disc, the optical disc comprising a plurality of tracks;
• a storing unit storing a table for listing a plurality of track classes and tracking errors respectively associating with the track classes, the plurality of track classes are defined based on track amount;
• a counting unit counting the number of tracks between a current track at which the optical head is positioned and a target track from or to which the optical head reads or writes data;
• a first determining unit determining whether the number of the tracks reaches a predetermined number;
• a long tracking unit calculating first jumping tracks when the number of the tracks reaches the predetermined number;
• and
• a searching unit searching the table for the tracking error associating with one of the track classes which corresponding to number of the tracks;
• wherein the long tracking unit calculates second jumping tracks based on the first jumping tracks and the found tracking errors, and drives the optical head to move to the second jumping tracks for tracking.