| 摘要 |
PURPOSE:To execute high density recording by recording ternary values making three kinds of phase of an amorphous phase at the center of recording mark, a coarse crystal peripheral part of recording mark and an intial amorphous phase. CONSTITUTION:Signal level are converted into ternary values of 0, 1 and 2. Recording is executed with a recording leser pulse P corresponding to these ternary values. Recording track T is in amorphous phase in a form of film as produced. On these initial amorphous tracks, the ternary mark M is made with recording laser pulse. For reproducing, ternary information is reproduced making the amorphous part b at the center of recording mark M represent level 2, the coarse crystal part a, c neghboring the recording mark M level 1 and initial amorphous part d 0 level. Thus, the high density recording is possible with the amorphous part b, coarse crystal parts a, c and the initial amorphous part d. |
