Hitachi Maxell, Limited

Hitachi Maxwell, Ltd.

Yasuhiko Kokufuda

Osamu Ishizaki

Tsuyoshi Maro

Hideo Daimon

Hiroyuki Hirata

Tatsuo Araki

Makoto Aihara

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&mdash;P plating. The surface of the plating is polished with abrasive grains to obtain surface roughness of Ra&lE;2.0 nm and Rmax&lE;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.

Substrate for information recording disk, mold and stamper for injection molding substrate, and method for making stamper, and information recording disk

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.ltoreq.2.0 nm and Rmax.ltoreq.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.

Substrate for information recording disk, mold and stamper for injection

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Kyoto, Japan

Yasuhiko Kokufuda