Mitsubishi Kagaku Media Co., Ltd.

Mitsubishi Chemical Corporation

Hitachi Maxell, Limited

Jun Kanehira

Osamu Ishizaki

Kenjirou Kiyono

Akio Okamuro

An optical recording medium includes a plane ring-shaped substrate in which a center hole is opened at the center thereof, a recording-retrieving function layer and a cover layer each having an outer diameter approximately equal to that of the substrate and an inner diameter larger than an outer diameter of the center hole, are stacked on the substrate, and as a separate entity from the cover layer, a clamp portion which is for holding and fixing the substrate and which has an outer diameter smaller than inner diameters of the recording-retrieving function layer and the cover layer, is provided around the center hole in a region where the cover layer is not formed.

Optical recording medium

An optical recording medium simultaneously having higher recording characteristics and storage stability than ever, is obtained. An optical recording medium comprising at least a phase change recording layer, a first diffusion preventing layer, a second diffusion preventing layer and a protective layer formed in this order on a substrate, characterized in that the first diffusion preventing layer and the second diffusion preventing layer comprise a non-gas element and nitrogen and/or oxygen as the main components, the non-gas element in each of the first diffusion preventing layer and the second diffusion preventing layer, is the same, and the content (atomic %) of nitrogen and/or oxygen contained in the second diffusion preventing layer, is larger than the content (atomic %) of nitrogen and/or oxygen contained in the first diffusion preventing layer.

Growing community of inventors

Kurashiki, Japan

Jun Kanehira