Tdk Corporation

Setsuko Shibuya

Hideki Hirata

Toshifumi Tanaka

Atsuko Motai

Hiroyuki Endo

Isamu Kuribayashi

Tsuneo Kuwahara

Shin-ichi Tezuka

Ryota Uchiyama

A protective coating made of resin, preferably a radiation curable resin containing fluoroplastic fine particles having a low surface energy is provided in the form of the uppermost layer facing a magnetic head, thereby improving the frictional properties and durability of a magneto-optical disc that is used with a magnetic field modulation system in which the magnetic head comes in constant contact therewith.

Magneto optical disc

An optical recording disk includes a resin substrate having a recording layer thereon and a protective glass substrate, which are joined into an integral disk such that the recording layer is inside. The resin substrate is formed of a resin composition comprising a specific cyclic polyolefin and an optional alkyl phenol condensate. The resulting lightweight, rigid disk is adapted for recording/reproducing operation at high rotational speeds with few focusing errors due to minimized axial runouts.

Optical recording disk

An optical recording disk is constructed using a substrate which is injection molded from a mixture of a cyclic polyolefin and up to 2% by weight of an alkyl phenol condensate. A recording layer remains firmly adhered to the substrate even in a hot humid environment.

Optical recording medium

Growing community of inventors

Saku, Japan

Setsuko Shibuya