| 摘要 |
PURPOSE:To easily center the information tracks of an optical disk by providing the same circular grooves or arc grooves thereto. CONSTITUTION:This optical disk is constituted by including an optical disk substrate 1, an optical disk information track region 2 and plural pieces of the circular grooves 3 which are provided on the inside of the optical disk information track region 2 and having the same center as the center of the optical disk information track region. The centering grooves 4 are centered to the central position of a centering device which is installed on a table 5. The pitch of the centering grooves 4 is the same as the pitch of the circular grooves 3. The centering of the information tracks of the optical disk is thus efficiently executed without complicated operations. |
