| 摘要 |
A non-circular optical disk is provided to prevent an optical disk from being separated from an optical disk setting unit of a tray, and to suppress a shaking phenomenon while the disk is played, thereby manufacturing the optical disk in various designs. Outer contact units are formed so as to correspond to the inner circumference of a circular disk setting groove where a disk of an optical disk recording or reproducing device is inserted, so that more than two parts of an end farthest from the central point of a central hole(21) of an outer shape unit(25) formed in non-circular shape are configured in the same length. Each of the adjacent outer contact units is disposed at less than 180 degrees on the central point of the central hole(21). |
