Patent ID: 9099105
Filing Date: 2015-08-04
Classification: G11B

Abstract:
1. A information recording medium having a disk shape comprising: a substrate having a predetermined thickness; a first surface forming one surface of the substrate; a second surface forming the other surface of the substrate; a cylindrical portion in which a through hole penetrating a center of the substrate is formed; a first recording region formed on a first surface side; a second recording region formed on a second surface side; a first clamp region with which a clamper is brought into contact when the first recording region is reproduced, the first clamp region being formed on the first surface side; a second clamp region with which a clamper is brought into contact when the second recording region is reproduced, the second clamp region being formed on the second surface side; a first rib formed in a circular annular shape on the first surface side and on an inner peripheral side of the first clamp region; a second rib formed in a circular annular shape on a second surface side and on an inner peripheral side of the second clamp region; and a first printing region formed between the first rib and the first recording region.