Patent ID: 6754166
Filing Date: 2004-06-22
Classification: G11B

Abstract:
An optical recording medium for recording information by irradiating a recording layer with a laser beam to form a recording mark thereon and for reading recorded information by irradiating the recording mark with a reading laser beam, said optical recording medium comprisinga virtual recording cell set contiguously on said recording layer along a track in a direction of relative displacement between the laser beam and said recording layer, the virtual recording cell being provided with a given unit length in the direction and a unit width in a direction orthogonal thereto, the track being provided with a track pitch defined to be 1 &mgr;m to 1.5 &mgr;m in the orthogonal direction, wherein a recording mark can be formed on said recording layer in the virtual recording cell, said recording mark having at least different one of a size and an optical transmittance corresponding to five stages or more of modulation of at least one of an irradiation time and an irradiation power of the laser beam, and optical reflectivity of the entire virtual recording cell is modulated to thereby enable multi-level recording of information in five stages or more in accordance with at least one of an area ratio of the recording mark to the virtual recording cell and an optical transmittance of the recording mark.