Optical recording medium
AssigneeMitsubishi Kagaku Media Co., Ltd.
InventorsYoshihiro Noda, Shigeyuki Furomoto
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Abstract
In an optical recording medium having two recording layers of a first recording layer and a second recording layer, the second recording layer contains metallized azo dyes represented by the following general formula (I) or (II), and recording characteristics of the second recording layer are improved by having optical density of 1.3 times as large as, or 1.3 times greater than, that of a dye contained in the first recording layer. (In this regard, rings A1 and A2 are nitrogen-containing heteroaromatic rings, rings B1 and B2 are aromatic rings, and X is alkyl group substituted by at least two fluorine atoms).
Claims11
An optical recording medium, comprising:
- a first recording layer comprising a dye and capable of recording/reading information by light;
- and
- at least one second recording layer comprising a dye,
- wherein
- the optical density of the dye contained in the second recording layer is greater than that of the dye contained in the first recording layer which is the closest to a side from which the light is irradiated;
- the optical density of the dye contained in the second recording layer is 0.005 or greater, and 0.015 or smaller;
- and
- the recording/reading of information on the first recording layer and the second recording layer is possible using light irradiated from one side of the optical recording medium.
An optical recording medium comprising two recording layers, wherein
- a second recording layer comprising a nickel azo dye having a greater optical density than that of a dye contained in a first recording layer in order that a ratio of(P2)/(P1) is less than 1.16, the P1 being a recording power to record information in the first recording layer provided on a side where the recording light is made incident, and the P2 being a recording power to record information in the second recording layer provided on a side distant from the side where the recording light is made incident;
- and
- the recording/reading of information on the first recording layer and the second recording layer is possible using light irradiated from one side of the optical recording medium.
An optical recording medium, comprising:
- a first recording layer comprising a dye and capable of recording/reading information by light;
- and
- at least one second recording layer comprising a dye,
- wherein
- the optical density of the dye contained in the second recording layer is greater than that of the dye contained in the first recording layer which is the closest to a side from which the light is irradiated,
- the recording/reading of information on the first recording layer and the second recording layer is possible using light irradiated from one side of the optical recording medium, and
- the dye contained in the second recording layer is selected from metallized azo dyes represented by at least one of following general formula (I) and general formula (II):
- wherein the rings A1 and A2 are nitrogen-containing heteroaromatic rings that can respectively have independent substituents, rings B1 and B2 are aromatic rings that can respectively have independent substituents, and X is an alkyl group with carbon numbers 1 to 6 substituted by at least two fluorine atoms.
Dependencies are inferred from the claim text.