JPS6437723A - Method for recording, reproduction and erasing optical information - Google Patents

Abstract

PURPOSE:To attain erasing and recording simultaneously with a single spot laser light by providing a means to modulate the power level of the laser light, setting the power level at the level or more, to make a recording member into a liquid phase condition at an erasing level, and setting the power level at the level to make the member into a crystalization transfer temperature or more in a solid phase condition at a recording level. CONSTITUTION:The modulation power level of the laser light is selected into a high power level 8, low power level 9 and a reproducing power level 19, and the modulation laser light is radiated to the same track 10. Parts 14, 15, 16 and 18, to which the low power level is irradiated, are crystalized, blackened, and go to the mark of a recording signal. In such a case, since the part of a crystalization recording signal mark 13 receives the irradiation of the high power level 8, the part fuses, returns to an amorphous condition 17, and the signal mark is erased. The low power level 9 is radiated to the section 12 between signal marks, and a crystalizing signal mark 16 is newly formed. Thus, the information can be recorded and erased with a single approximately-circular spot.