Method of defect detection for optical disc drives

A method of detecting disk defects in an optical disc for an optical disc drive including an optical pickup, the method comprising the steps of:

• emitting light from the optical pickup onto the optical disc and obtaining reflected sub-beams;
• generating a reflected light intensity signal based on the reflected sub-beams;
• obtaining a low-frequency signal after the reflected light intensity signal is processed through a low-pass filter;
• and
• storing the low-frequency signal if a defect signal indicating existence of the disk defects appears based on a difference between the reflected light intensity signal and the low-frequency signal.

An optical disc drive for use in a data reproduction system utilizing a defect management system, the optical disc drive comprising:

• an optical pickup capable of emitting light onto an optical disc and obtaining reflected sub-beams;
• a low-pass filter for obtaining a low-frequency signal from a reflected light intensity signal, the reflected light intensity signal being based on the reflected sub-beams;
• and
• a holding circuit for holding the low-frequency signal when a difference between the reflected light intensity signal and the low-frequency signal is greater than a predetermined value.