| 摘要 |
PROBLEM TO BE SOLVED: To precisely form recording marks having the width equal to or smaller than the beam diameter by the constitution of a simple recording pulse at the time of multi-valued information recording. SOLUTION: The recording pulse waveform for modulating the intensity of laser beams is constituted of such a pulse waveform that a rectangular erase pulse, a rectangular recording pulse, an off-pulse and the above rectangular erase pulse are continuously repeated, and also by setting widths T2-T1 of the recording pulse to be shorter with respect to the length ML in the circumferential direction of the recording mark to be formed, the recording mark is expanded also to the area of the off-pulse width by the influence of the thermal diffusion due to the laser beams corresponding to the widths T2-T1 of the recording pulse, then the desired recording mark can be formed due to that the recording mark expanded by the erase pulse arranged behind the off-pulse is erased.
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