Patent ID: 8179764

Claim:
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 a 25±10 μm-thick layer arranged between the first and second recording layers, and an area configured to store information relating to a polarity of the mark, the polarity being able to indicate the low-to-high characteristic.