| 摘要 |
An optical recording medium having each of a land and a groove and comprises at least a recording layer, dielectric layers and reflection layer. Recording and erasing of data can be carried out on both land and groove by a phase change between amorphous and crystalline states. The mirror portion may have reflectance characteristics selected from at least one of a reflectance of more than 15% and no more than 35%, when in a crystalline state, and 10% or less, when in an amorphous state. Alternatively, additionally, the depth of the groove may be such as to form an optical path length equal to +E,fra 1/7+EE to +E,fra 1/5+EE of the wavelength of the reproducing light and the photo-absorbance of the recording layer in the amorphous phase and the photo-absorbance in the crystalline phase may satisfy the following formula, Aa-Ac</=10 where Aa is the photo-absorbance (%) of the recording layer in the amorphous phase and Ac is the photo-absorbance (%) of the recording layer in the crystalline phase. In an optical recording method, an edge type recording system is provided on an optical recording medium in which recording and erasing are effected by a phase change between amorphous and crystalline states. Recorded marks are provided by pulse trains each comprising a number of recording power pulses and, additionally, a power pulse, after the last of the recording power pulses, of a power less than a erase power and of a duration in a range of 1.1 to 6 times the duration of the last recording power pulse.
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