Optical recording medium, information recording method, and information reproducing method
According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.
1. An optical disc comprising first and second recording layers configured to store or reproduce information by light with a predetermined wavelength, the information being configured to be recorded on the first or second recording layer using a mark and a space, and the first or second recording layer having a low-to-high characteristic, wherein
a channel clock period is represented by T, the channel clock period T being provided for recording the mark on the first or second recording layer where the mark regarding 3T can be recorded,
a plurality of pulses including a last pulse arranged at an end of the pulses are used for recording the mark regarding 3T, the mark regarding 3T being configured to be recorded with a condition that a width of the last pulse is 0T at minimum and 1.10T at maximum, in which a first subsequent level lower than a peak power level of the last pulse is arranged next to the last pulse, and a second subsequent level lower than the peak power level but higher than the first subsequent level is arranged next to the first subsequent level, and
the optical disc further comprises an area configured to store information relating to a polarity of the mark, the polarity being able to indicate the low-to-high characteristic.
2. An information recording method using an optical disc comprising first and second recording layers configured to store or reproduce information by light with a predetermined wavelength, the information being configured to be recorded on the first or second recording layer using a mark and a space, and the first or second recording layer having a low-to-high characteristic, wherein
a channel clock period is represented by T, the channel clock period T being provided for recording the mark on the first or second recording layer where the mark regarding 3T can be recorded,
a plurality of pulses including a last pulse arranged at an end of the pulses are used for recording the mark regarding 3T, the mark regarding 3T being configured to be recorded with a condition that a width of the last pulse is 0T at minimum and 1.10T at maximum, in which a first subsequent level lower than a peak power level of the last pulse is arranged next to the last pulse, and a second subsequent level lower than the peak power level but higher than the first subsequent level is arranged next to the first subsequent level, and
the optical disc further comprises an area configured to store information relating to a polarity of the mark, the polarity being able to indicate the low-to-high characteristic, the method comprising:
recording information on the first or second recording layer.
3. An information reproducing method using an optical disc comprising first and second recording layers configured to store or reproduce information by light with a predetermined wavelength, the information being configured to be recorded on the first or second recording layer using a mark and a space, and the first or second recording layer having a low-to-high characteristic, wherein
a channel clock period is represented by T, the channel clock period T being provided for recording the mark on the first or second recording layer where the mark regarding 3T can be recorded,
a plurality of pulses including a last pulse arranged at an end of the pulses are used for recording the mark regarding 3T, the mark regarding 3T being configured to be recorded with a condition that a width of the last pulse is 0T at minimum and 1.10T at maximum, in which a first subsequent level lower than a peak power level of the last pulse is arranged next to the last pulse, and a second subsequent level lower than the peak power level but higher than the first subsequent level is arranged next to the first subsequent level, and
the optical disc further comprises an area configured to store information relating to a polarity of the mark, the polarity being able to indicate the low-to-high characteristic, the method comprising:
reproducing information from the first or second recording layer.