| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact disk medium device improved in its storage capacity. SOLUTION: The device includes a 1st flat surface 112 having an outside peripheral edge 116 for prescribing an outside circle. The outside circle prescribes a radius direction 126 extended from the center 122 of the circle to the edge 116. The 1st surface 112 includes an inside peripheral edge 120 for prescribing an inside circle. The inside circle is substantially concentric with the outside circle. The device includes a recording area 140 formed between both the edges 120, 116 and a non-recording area 150 formed adjacently to both of the recording area 140 and the edge 116. The non-recording area 150 is formed over a range <= about 0.9 mm from the edge 116 in a radius direction 126. The recording area 140 includes indents and lands, and especially an indent in an extended storage area 155 can be formed more deeply as compared with indents in other parts. |
