Hitachi Maxell, Limited

Hitachi Maxwell, Ltd.

Tatsuo Araki

Osamu Ishizaki

Tsuyoshi Maro

Hideo Daimon

Hiroyuki Hirata

Takeshi Ohnuki

Makoto Aihara

Yasuhiko Kokufuda

Susumu Shibasaki

Keisuke Okushiro

Hiroyuki Ohta

A magneto-optical recording medium comprises, on a substrate, a reflective layer, a first dielectric layer, a recording layer, and a second dielectric layer successively in this order, for being irradiated with a recording or reproducing light beam coming from a side of the second dielectric layer. A diamond-like carbon layer as a self-lubricating layer is formed on the second dielectric layer. An optical head comprises a floating type slider installed with a solid immersion lens. A protective film having a self-lubricating property may be also formed on a bottom surface of the slider opposing to the optical recording medium. Even when the floating position of the optical head is varied, and the optical head contacts with the surface of the optical recording medium, then the sliding scratch scarcely occurs, because the optical head smoothly glides on the recording medium surface. A lubricating layer may be further formed on the self-lubricating layer.

Optical recording medium, optical head, and optical recording device

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 recording disk comprises a substrate including a plastic material, and an overlay arranged over the substrate and including a recording substance for recording therein an information, and a radially-outer periphery of the overlay is received within a radially-outer periphery of the substrate as seen in an axial direction of the recording disk.

Recording disk and producing method therefor

Optical recording medium, optical head and optical recording device

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

An olefinic resin composition for molding, which comprises an olefinic resin, inorganic particles in rod shape and inorganic particles of planar crystalline structure respectively in 10 to 90% by volume, 3 to 60% by volume and 5 to 55% by volume based on the composition. A molded article made of such a composition is low in friction coefficient and high in mechanical strength. When this composition is incorporated with a synthetic resin having a higher hardness than the olefinic resin, the resultant molded article is enhanced in endurance on sliding. The resulting composition is suitable for manufacturing of a sliding member such as a tape guide.

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Ohtsu, Japan

Tatsuo Araki