PURPOSE: To obtain a stamper which generates no distortion of sound grooves nor ghost by providing a thermoplastic resin layer on the rear side of the stamper on which a projecting bar corresponding to information recording grooves is formed, and forming the rear side as a smooth surface.
CONSTITUTION: A recessed groove 2 corresponding to a projecting bar 1 for forming sound grooves by a press is left on the rear side of a stamper main body A. Therefore, a resin layer B is formed as a smooth surface by heating a thermoplastic resin and spraying it to the rear side of the stamper. In this way, at the time of pressing, even if a force (a) for spreading out the projecting bar 1 is applied, the sound grooves generate no deformation nor distortion. Also, even if a force (b) for pushing laterally the projecting bar 1 is applied by a crushed force of a projecting bar 1', its influence is not exerted, and no ghost is generated. Therefore, a stamper which generates no distortion nor ghost is obtained.
JPS549603 | MOLD FOR PRODUCING VIDEO DISK |
JPS54145102 | HIGH PACKING DENSITY INFORMATION CARRIER |
SUZUKI SHIYUUICHIROU