Patent ID: 6462903
Filing Date: 2002-10-08
Classification: G11B

Abstract:
In combination, a disc-shaped recording medium including a substrate molded from a synthetic resin, said substrate having a center opening, in which a signal recording region is formed on at least one surface thereof, and in which information signals are recorded and/or reproduced in a state in which a rotating recording and/or reproducing head is floated a pre-set distance from the surface carrying said signal recording region to record and/or reproduce the information signals for the disc-shaped recording medium; anda clamp mechanism including a supporting member arranged on one of the surfaces of said disc-shaped recording medium for supporting said one surface around said center opening and a thrusting supporting member arranged on the other surface of said disc-shaped recording medium for supporting said other surface around said center opening; said clamp mechanism being mounted on said disc-shaped recording medium as it clamps an area of said disc-shaped recording medium radially outside of the outer perimeter of the center opening by at least 0.1 mm or more, said area being coplanar with each surface of the disc-shaped recording medium carrying said signal recording region; wherein the contact portion of said supporting member and/or the thrusting supporting member has a maximum value of surface roughness not larger than 4 &mgr;m.