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AssigneeHitachi Maxwell, Ltd.
InventorsHiroyuki Hirata, Tatsuo Araki, Osamu Ishizaki, Hideo Daimon, Yasuhiko Kokufuda, Tsuyoshi Maro, Makoto Aihara
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A cavity surface-forming plate of a mold for injection-molding a plastic substrate is coarsely polished, and then a surface for defining a cavity is applied with electroless Ni—P plating. The surface of the plating is polished with abrasive grains to obtain surface roughness of Ra≦2.0 nm and Rmax≦22 nm. The plastic substrate molded with the mold has smoothness equivalent to the polished plating surface. A concave-convex pattern for forming pits may be formed on the cavity surface. A magnetic disk or an optical disk provided with the substrate makes it possible to realize the near contact system for a magnetic or magneto-optical head. Thus, it is possible to realize high density recording.
An injection molding mold for injection-molding a substrate for an information-recording disk, wherein:
A stamper for a mold used for molding a substrate for an information-recording disk by injecting and charging a molten resin into the mold, characterized in that:
A method for producing a stamper composed of a low hardness layer having a Vickers hardness of not more than 300 Hv and a high hardness layer having a Vickers hardness of not less than 500 Hv, the method comprising:
A stamper for a mold to be used for molding a substrate for an information-recording disk by injecting and charging a molten resin into the mold, wherein:
Dependencies are inferred from the claim text.