Ricoh Company, Ltd.

Keiko Ichinose

Tsutomu Satoh

Tsutomu Sato

Masaakira Umehara

Tsutomu Satou

Hideaki Ohba

Tatsuya Eida

An optical information recording medium is composed of a substrate, and a recording layer formed on the substrate, the recording layer including (a) a first recording layer, (b) an intermediate, and (b) a second recording layer, which are successively overlaid on the substrate, the first recording layer containing as the main component an organic dye having a peak of spectral reflectivity near the wavelength of a light beam for the recording and reproduction of information, the intermediate layer being transparent to the light beam for recording and reproduction of information, and containing a material having a refractive index smaller than the refractive index of the second recording layer, and the second recording layer containing as the main component an organic dye having a peak of spectral absorbance near the wavelength of the light beam for recording and reproduction of information, and having a thickness by which a maximum reflectivity is exhibited.

Optical information recording medium

An optical information recording medium comprising a substrate; a recording layer comprising as the main component an organic dye component, formed on the substrate, which recording layer has a maximum peak in the spectroscopic reflectance thereof near the wavelength of the information recording and reproduction light, and has a thickness at which the spectroscopic reflectance thereof is maximized at the wavelength of the information recording and reproduction light, and an optical information recording method, and a system for recording and/or reproducing information using this recording medium are disclosed.

Optical information recording medium, information recording method and

An optical information recording medium is disclosed, which comprises a plastic substrate; an undercoat layer formed thereon, comprising a condensate of a mixture of (1) at least one metal alcoholate selected from the group consisting of a tetra-alkoxy metal and an organic tri-alkoxy metal, and (2) a polymeric compound selected from the group consisting of (i) a copolymer of an acrylate or methacrylate containing at least one hydroxy alkyl group, and an acrylate or methacrylate containing an alkyl group, and (ii) an amino-group-containing polymer; and a recording layer formed on the undercoat layer.

An optical information recording medium comprises a plastic substrate and a recording layer containing an indole type polymethine compound wherein the substituents attached to N atoms in the indole and indolene rings must be different from each other. The compound provides high solubility in alcoholic solvents, high storage stability (light resistance, heat resistance, etc.) and the like.

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Yokohama, Japan

Keiko Ichinose