Clamping plate, cartridge case, information medium, mold, and method of manufacturing clamping plate

摘要

A clamping plate capable of reliably clamping a disk-shaped medium. In the clamping plate, at an imaginary intersecting portion between an imaginary extended surface of a rear surface of an outer peripheral portion of a main body and an imaginary extended surface of a rear surface of an inner peripheral wall of the main body, an annular groove recessed from the imaginary extended surfaces in the directions of the thicknesses of the outer peripheral portion and the inner peripheral wall is formed along an imaginary cross line of the imaginary extended surfaces.