| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical recording medium with which the jitter of reproduced signals may be suppressed and higher density recording may be attained by reducing the shape distortion of recording marks even at the time of overwriting. SOLUTION: When the phase of the reflected light from the amorphous phase recording marks in a recording layer is defined as ϕa and the phase of the reflected light from a crystal phase as ϕc, both phase are so set that the absolute value of the phase difference Δϕ (=ϕa-#c) between both satisfies the relation 240 deg.>|Δϕ|>120 deg., by which the reproduced signal by the phase difference Δϕ may be taken larger. The absorptances of the crystal phase and the amorphous phase recording mark are approximately same or that of the crystal phase is layer by the absorptance control and, therefore the shape distortion of the recording marks at the time of overwriting is suppressed. The jitter of the reproduced signal is, therefore, suppressed and eventually the higher- density recording is embodied. |
