MOLD FOR MOLDING DISK SUBSTRATE AND DISK SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To further reduce molding defects in the substrate of a disk as an optical information recording medium. SOLUTION: A fixed mold 5 in which a sprue 56 is installed in the middle, a movable mold 6 which forms a disk-shaped cavity 9 between it and the fixed mold 5, a stamper 7 arranged on the surface of the movable mold 6, and a cutting punch 64 which is installed hauntably in the middle of the movable mold 6 and gate-cuts the sprue 56 are provided, and the outside surface 64c of the punch 64 is roughened to be 0.2-500μm in roughness.