Abstract:
The disk-shaped information recording medium having an outer diameter and an inner diameter comprises a substrate having a predetermined thickness, a first side that is one side of the substrate, a second side that is the other side of the substrate, a cylindrical portion forming a through hole formed at a center of the substrate, and a thin portion formed so as to surround an outer diameter of the cylindrical portion. The thin portion is thinner than the predetermined thickness and includes a non-inclined surface and an inclined surface formed on an outer diameter side of the non-inclined surface. The inclined surface is inclined at an angle greater than or equal to 25 degrees and less than or equal to 35 degrees with respect to the non-inclined surface.
Abstract:
An information recording medium of the present exemplified embodiment is configured by laminating a substrate having a predetermined thickness and a substrate having a predetermined thickness to each other. A film forming region including a recording region, a clamp region and a rib are formed on one surface of the information recording medium. A film forming region including a recording region, a clamp region and a rib are formed on the other surface of the information recording medium. On both surfaces, the components are formed in the order of the rib, the clamp region and the film forming region toward an outer peripheral side from an inner peripheral side.