| 摘要 |
PROBLEM TO BE SOLVED: To provide an information recorder, etc., capable of stably recording or reproducing multi-valued information by a simple method on or from a phase transition recording medium. SOLUTION: In the information recorder for recording the information as the recording mark by using a light spot with respect to the phase transition recording medium the position of the rear end edge of the recording mark is modulated in the scanning direction of the light spot in accordance with the recording information. The light spot is formed by a laser beam and the modulation is made by changing the power level of the laser beam with two or more steps. When the multi-valued information is recorded, the plural recording marks are combined to make them to one unit, and the multi-valued information is expressed by the combination of the individual position of the recording marks in the one unit and the position of the rear end edge of the mark.
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