| 摘要 |
PURPOSE:To enable high density information recording by performing both recording by a first signal level that a bit is formed on only a first recording layer and recording by a second signal level that the bit is formed on both the first recording layer and a second recording layer by adjusting laser beam absorption quantity. CONSTITUTION:A highly reflective reflecting layer 4, the second recording layer 3 with the reflection factor lower than that of said reflecting layer, and the first recording layer 2 with the reflection factor lower than that of the second recording layer 3 are laminated on a substrate 1 by said order from an upmost layer toward a substrate surface. Then, by adjusting the irradiation time and the powder of laser beam to be used, the laser beam of the first signal level to form the bit on only the first recording layer 2 and the laser beam of the second signal level to form the bit on both the first recording layer 2 and the second recording layer 3 are generated, and the recording is performed by using the laser beam of these two kinds of the signal levels. Thus, recording density about double as dense as a traditional optical information recording medium to record information by changing bit size is obtained. |
