| 摘要 |
PURPOSE:To avoid the damage caused on the surface of a substrate by the external mechanical force and at the same time to eliminate the eccentricity that is caused when an information recording carrier is loaded to a reproducer, by providing a projection on the surface of an information recording medium (disk) to which the information is optically recorded. CONSTITUTION:A disk is produced with use of a metallic mold by which a projection 10 is formed at the outer circumference of the surface 2 of an optical disk substrate 1. Thus the surface 2 when placed on a desk, etc. is free from any damage caused by the dust, etc. or from any fault arising during the reading of an information pit 3. Otherwise the projection 11 is provided at the center of the surface 2, and the inner diameter of a center hole 7 is set slightly larger than the outer diameter of a main shaft 12 of a rotary motor 13. Thus the outer diameter of the projection 11 can be correctly fitted to the inner diameter of a disk positioning pedestal 14. As a result, an accurate coincidence is obtained between the center of the disk and that of the shaft 12, and at the same time the damage can be prevented on the surface of the disk. |
