Patent ID: 6101163
Filing Date: 2000-08-08
Classification: G11B

Abstract:
An optical disc apparatus for reproducing thermomagnetically recorded data recorded on an optical disc with reference to a waving of a groove formed on said optical disc comprising:signal generating means for generating a reproduction signal having a signal level varying correspondingly to a polarization plane of a reflected beam by use of a differential output signal of first and second beam outputted signals having signal levels varying complementarily correspondingly to a polarization plane of said reflected beam obtained by irradiation of a light beam onto said optical disc and for generating a wobble signal having a signal level varying correspondingly to the waving of said groove from said reflected beam;band restricting means for extracting and outputting a signal component of said wobble signal from said reproduction signal;signal level detecting means for detecting the signal level of said wobble signal and outputting the signal level detection result; phase comparison means for comparing the phase of the signal component of said wobble signal with that of said signal level of said wobble signal to output the phase comparison result; andsignal level correcting means for correcting the signal level of the first and second beam outputted signal based on said signal level detection result and said phase comparison result.