| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a phase transition type optical information recording medium wherein a recording pit by which large capacity data storage is made possible has a binary or more recording and reproducing signal level. <P>SOLUTION: In the phase transition type optical information recording medium between a crystal state and an amorphous state by irradiation with light, multi-valued recording marks are formed in a region which is divided into equal areas and in which the recording marks are to be formed and recording/reproducing is performed by the recording marks. On a substrate, a groove having 0.45 to 0.50 μm track pitch and 0.20 to 0.30 μm groove width is formed and a first protective layer, a phase transition recording layer, a second protective layer and a reflection layer are provided in this order. The second protective layer consists essentially of at least two selected from Nb, Si and Ta. The reflection layer consists essentially of Ag. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
