Stamper plate attaching/detaching device of injection mold for optical disc substrate

摘要

A stamper plate attaching/detaching device of an injection mold for an optical disc substrate is used for a mold wherein the stamper plate is supported in a cavity which is formed by a cavity side disc cavity plate, a movable disc cavity plate, and a cavity ring. The stamper plate attaching/detaching device is equipped with: a section for holding the outer circumferential rim of the stamper plate by means of the inner circumferential rim of the cavity ring, which inner circumferential rim is made larger than the outer diameter of the stamper plate; a plurality of pairs of permanent magnets which have magnetic poles in parallel to the central line and which are buried, with phase differences, on the same radial line of the cavity side disc cavity plate and the movable disc cavity plate; and rotating means for giving the cavity ring a relative rotation between a first angle position and a second angle position in relation to the cavity side disc cavity plate and the movable disc cavity plate.