| 摘要 |
PROBLEM TO BE SOLVED: To obtain an excellent characteristic even in either recording area and to make possible easily revising specification also by sticking two substrates forming a recording layer each other and changing a signal recording area each other. SOLUTION: A first substrate 2 forming the recording layer 1 and a second substrate 4 forming the recording layer 3 are stuck each other opposing the sides forming the recording layers 1, 3 each other. Signal recording areas 6, 8 are formed on the first substrate 2 and the second substrate 4 respectively. Then, the signal recording areas 6, 8 are different from each other in the first substrate 2 and the second substrate 4. |
