| 摘要 |
PURPOSE:To reduce the thickness and to improve the reliability for an optical information recording disk by forming a projecting part to a recording area to secure a air layer and adhering the projecting part to the non-recording areas set at both sides. CONSTITUTION:The center part of a protection cover 15, i.e., the part corresponding to a recording area of a substrate 10 is circularly protruded as a projecting part 16. At the same time, the inner and outer fringe parts 17 and 18 of the cover 15 are adhered to the non-recording areas 13 and 14 of a substrate 10. Then a sealed-up air layer 19 is formed on the recording area via the part 16. As a result, the total thickness of the disk outer circumferential part is equal to the sum of the thickness of the substrate 10 and that of the cover 15. Then the thickness of the recording area is increased with the thickness of the layer 19 only. As a result, the thickness of an optical information recording disk is reduced. |
