Pioneer Corporation

Tdk Corporation

Ayumi Mitsumori

Yasuo Hosoda

Satoshi Jinno

Masataka Yamaguchi

Megumi Sato

Hiroyasu Inoue

Koji Mishima

Tetsuya Iida

Masaki Aoshima

Hideo Kudo

Takuma Yanagisawa

Takanobu Higuchi

Yoichi Okumura

Tomoaki Izumi

A multilayer optical recording medium in which, as a recording layer is located farther from a surface of incidence of a light beam for reading, the amount of light that reaches the surface of incidence after being reflected off the recording layer is smaller.

Optical recording medium

An information recording medium has an excellent jitter characteristic with a considerable difference in reflectance between prior to and subsequent to recording. The information recording medium includes a recording layer which contains a material having a reflectance which varies by irradiation of a light beam, on which information is recorded as reflectance variations, and a substrate for supporting the recording layer, the recording layer including a metal nitride as a major component. In a method of manufacturing the information recording medium having a recording layer which includes a material having a reflectance which varies by irradiation of a light beam, on which information is recorded as reflectance variations, and the substrate for supporting the recording layer, the recording layer including a metal nitride as a major component, the method includes a recording layer forming step for forming the recording layer by a reactive sputtering method which uses a target comprised of a metal constituting a metal nitride, wherein a flow ratio Ar:Nin an atmosphere including Ar and Nin the recording layer forming step is set within the range of 80:10 to 10:80.

Information recording medium and process for producing the same

An optical recording medium includes a recording layer containing an alloy represented by a general formula: (TiM)M, where element Mis Si or Al, element Mis an element selected from the group consisting of Si, Al and Fe and different from the element M, x is equal to or larger than 0.3 and equal to or smaller than 0.8, and y is equal to or larger than 0.75 and equal to or smaller than 1. The thus constituted optical recording medium only places minimal load on the global environment.

Optical recording medium, method for manufacturing the same and target used for sputtering process

An optical recording medium includes a recording layer containing as a primary component an alloy containing at least two elements selected from the group consisting of Fe, Al and Si and the alloy contained in the recording layer as a primary component has a composition [x, y, z] in terms of the ternary composition diagram that falls within a region of a pentagon defined by straight lines connecting points [57, 43, 0], [0, 55, 45], [15, 0, 85], [89, 11, 0] and [0, 16, 84] in the ternary composition diagram. According to the thus configured optical recording medium, only minimal load is placed on the global environment.

An object of the present invention is to provide a phase-change optical recording medium of an amorphous recording mark type. The optical recording medium is a write once type medium capable of decreasing the degradation of an information signal which has been already recorded. The recording layer of the optical recording medium according to the present invention includes a first recording layer and a second recording layer. The first recording layer comprises a first composition which can be changed into another composition more stable in an amorphous state by combining with a component included in the second recording layer.

Write once optical recording medium

A film constitution in an optical recording medium including a light incident side substrate and a light reflecting side substrate cooperatively acting as a base of the medium, and includes, between these substrates, those layers formed by sputtering so as to constitute a laminated structure, which layers include: a phase-change recording layer to be phase-changed between an amorphous phase and a crystal phase by laser light irradiation; a first dielectric layer and a second dielectric layer, each having a protective function and an optical adjusting function for the phase-change recording layer; a reflecting film layer for reflecting the laser light transmitted through the phase-change recording layer; a hardness enhancing layer for enhancing the mechanical strength of the medium; and a protecting layer having a function for reducing thermal damages to the light incident side substrate and an optical adjusting function.

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Tsurugashima, Japan

Ayumi Mitsumori