| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to prevent the degradation in reliability at the time of preservation at a high temp. by providing a medium with a recording layer of a phase transition type and setting a linear speed at which C/N is maximized when overwriting is executed at a specified value. SOLUTION: If the linear speed, at which the C/N is maximized when the overwriting is executed at the linear speed V0, is defined as Vmax, the linear speed is so set as to attain 1<Vmax/V0,1.5. V0 may be a specified value or may be variable. This medium is applicable also to a ZCAV disk which concentrically has plural regions to be subjected to the overwriting at the respectively equal linear speeds and is slower in angular speed in the region existing nearer the outer periphery. The overwriting to the optical recording medium is execute by a laser beam modulated to include at least two values of a recording level and an erasing level. The one signal is recorded by at least two times of irradiation, thereby, the heat accumulation with the recording marks is suppressed and the tear drop phenomenon at the rear ends of the recording marks can be suppressed. |
