| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a phase-change optical disk of CAV method which prevents recrystallization even when information is recorded in an interior peripheral part, controls degradation of a reproduced signal even during frequent rewriting and the erasing residue of amorphousness is small even in the exterior peripheral part. <P>SOLUTION: The information recording medium includes a substrate and a recording layer which is re-writable in multiple times and records information by a phase change with laser beam irradiation of wave length of at least 390 nm and not longer than 420 nm, wherein a recording layer material includes Bi, Ge, and Te and has composition ratios which are within a range surrounded by composition points of B2 (Bi<SB>2</SB>, Ge<SB>47</SB>, Te<SB>51</SB>), C2 (Bi<SB>3</SB>, Ge<SB>47</SB>, Te<SB>50</SB>), D2 (Bi<SB>4</SB>, Ge<SB>47</SB>, Te<SB>49</SB>), D6 (Bi<SB>16</SB>, Ge<SB>37</SB>, Te<SB>47</SB>), C8 (Bi<SB>30</SB>, Ge<SB>22</SB>, Te<SB>48</SB>), and B7 (Bi<SB>19</SB>, Ge<SB>26</SB>, Te<SB>55</SB>) on a triangular composition diagram with Bi, Ge and Te respectively on each vertex. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
