| 摘要 |
PURPOSE:To allow the prevention of the degradation in tracking signals even if a track pitch is narrowed, by which stable tracking is executed. CONSTITUTION:A material A having the reflectivity lower than the reflectivity of a recording layer M or the absorbance higher than the absorbance of the recording layer is provided between the valleys of guide grooves G. The reflected light quantity is smaller when a laser spot exists in the guide groove G if the time when a laser spot exists in the land L and the time when the laser spot exists in the guide groove g are compared in this way. Then, the min. value of a track count signal (sum signal) is smaller than the min. value of the conventional media and the amplitude of the divided push pull signal (the signal obtd. by dividing the differential signal by a sum signal) increases and this signal can be used as a tracking error signal, by which the stable tracking is executed. |
