DISK MOLD AND OPTICAL DISK

摘要

PURPOSE: To prevent the appearance deficiency of an optical disk caused by a flow mark by forming the cavity constituting surfaces corresponding to the clamping areas of the upper and rear surfaces of the disk substrate of a disk mold as embossed surfaces. CONSTITUTION: A disk mold demarcates a disk-shaped cavity C in a clamped state to mold a disk substrate D having a center hole H. The clamping areas A of the upper and rear surfaces of the disk substrate D are subjected to satin finish by the embossed surfaces on the side of the mold simultaneously with molding. Since satin constituted of fine recessed and protruding parts and has light reflecting action (irregular reflection of light) perfectly different from a smooth surface, the flow marks on the clamping areas A of the disk substrate D can be concealed by the light reflecting action even when they are generated and the appearance deficiency due to the flow marks is prevented to enhance the productivity.