Patent ID: 6657930
Filing Date: 2003-12-02
Classification: G11B

Abstract:
A tracking control circuit for making a light beam follow a wobbling track formed on an optical recording medium, comprising driving means for driving said light beam across said wobbling track under a tracking error signal generated in accordance with a reflected beam from said optical recording medium, of said light beam incident on said optical recording medium, said tracking control circuit further comprising:light detector for receiving said reflected beam, said light detector being divided into at least four sections by a first dividing line optically parallel to a tangent direction of said wobbling track and a second dividing line optically parallel to a direction orthogonal to the tangent direction; first computing circuit for obtaining a difference between the output signals from a first divided light receiving section and a third divided light receiving section located on a first diagonal line on said light detector, to output a first differential signal; second computing circuit for obtaining a difference between the output signals from a second divided light receiving section and a fourth divided light receiving section located on a second diagonal line on said light detector, to output a second differential signal; and phase comparing circuit for comparing said first differential signal and said second differential signal in phase to output said tracking error signal.