Patent ID: 6889381

Claim:
An optical recording medium having an information signal area on which an information signal can be recorded and/or reproduced, said medium comprising: a disc substrate layer; and a light transmitting layer, wherein, said information area is formed on said disc substrate layer, said light transmitting layer transmits a laser beam for recording and/or reproducing the information signal, said information signal is formed within said information signal area, a clamp reference plane is arranged on said light transmitting layer, said light transmitting layer comprises a light transmitting sheet and an adhesive layer and said light transmitting sheet is adhered to a surface of said disc substrate layer, said disc substrate layer has a flat annular shape having a first opening in a center, said light transmitting layer has a flat annular shape having a second opening in a center and a diameter of said second opening is larger than a diameter of said first opening and smaller than an inner circumference diameter of a clamp region in said disc substrate layer, said adhesive layer is made of a pressure sensitive adhesive through which said laser beam can be transmitted, and the outer diameter of the light transmitting sheet having the flat annular shape is smaller than the outer diameter of the disc substrate layer having the flat annular shape.