Optical recording medium
AssigneeTDK Corporation
InventorsMasahiro Shinkai, Sumiko Kitagawa, Kenryo Namba, Emiko Yoshimura, Atsushi Monden, Takahiko Suzuki
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Abstract
The invention provides an optical recording medium comprising at least two recording layers containing a dye. At least two layers of the recording layers have different optical constants, and at least one among these recording layers having different optical constants contains a dye which forms a thin film having an absorption spectrum whose half-value width is up to 170 nm. This construction permits the medium to be written and read in a conventional wavelength range of about 780 nm and a shorter wavelength range of about 630-680 nm.
Claims10
An optical recording medium comprising at least two recording layers containing a dye on a substrate and a reflective layer thereon, comprising:
- at least two layers of said recording layers have different optical constants, and at least one among said recording layers having different optical constants contains a dye which forms a thin film having an absorption spectrum with a half-value width up to 170 nm;
- among said recording layers having different optical constants, at least one layer contains a dye A having a complex index of refraction at 780 nm with a real part n 1.8 to 2.8 and an imaginary part k up to 0.15 and forming a thin film having an absorption spectrum with a half-value width up to 170 nm and at least one distinct layer contains a dye B having a complex index of refraction at 630 nm or 650 nm with a real part n 1.8 to 2.8 and the imaginary part k is up to 0.4;
- said dye B is a trimethinecyanine dye of the following formula:
- ##STR287## wherein X.sup.- is a monovalent anion;
- each of Q.sub.3 and Q.sub.4 is a group of atoms necessary to complete an indolenine or benzoindolenine ring with the pyrrole ring, the rings completed by Q.sub.3 and Q.sub.4 may be the same or different;
- and
- R.sub.3 is a hydrogen atom or monovalent substituent;
- each of R.sub.4 and R.sub.5 is an alkyl radical.
An optical recording medium comprising at least two recording layers containing a dye on a substrate and a reflective layer thereon, comprising:
- at least two layers of said recording layers have different optical constants, and at least one among said recording layers having different optical constants contains a dye which forms a thin film having an absorption spectrum with a half-value width up to 170 nm.;
- among said recording layers having different optical constants, at least one layer contains a dye A having a complex index of refraction at 780 nm with a real part n 1.8 to 2.8 and an imaginary part k up to 0.15 and forming a thin film having an absorption spectrum with a half-value width up to 170 nm and at least one distinct layer contains a dye B having a complex index of refraction at 630 nm or 650 nm with a real part n 1.8 to 2.8 and an imaginary part k up to 0.4;
- said dye B is a trimethinecyanine dye of the following formula:
- ##STR288## wherein each of Q.sub.1 and Q.sub.2 is a group of atoms necessary to complete a heterocyclic ring with the carbon and nitrogen atoms, the heterocyclic skeletons completed by Q.sub.1 and Q.sub.2 may be the same or different;
- each of R.sub.1 and R.sub.2, which may be the same or different, is an aliphatic hydrocarbon radical, R.sub.3, is a hydrogen atom or monovalent substituent:
- X.sup.- is a monovalent anion;
- and wherein a singlet oxygen quencher is used as a stabilizer along with said trimethinecyanine dye.
An optical recording medium comprising at least two recording layers containing a dye on a substrate and a reflective layer thereon, comprising:
- at least two layers of said recording layers have different optical constants, and at least one among said recording layers having different optical constants contains a dye which forms a thin film having an absorption spectrum with a half-value width up to 170 nm.;
- among said recording layers having different optical constants, at least one layer contains a dye A having a complex index of refraction at 780 nm with a real part n 1.8 to 2.8 and an imaginary part k up to 0.15 and forming a thin film having an absorption spectrum with a half-value width up to 170 nm and at least one distinct layer contains a dye B having a complex index of refraction at 630 nm or 650 nm with a real part n 1.8 to 2.8 and an imaginary part k up to 0.4;
- said dye B is a sub-phthalocyanine boron complex of the following formula:
- ##STR290## wherein each of R.sub.21, R.sub.22, R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, R.sub.29, R.sub.30, R.sub.31, and R.sub.32, which may be the same or different, is selected from the group consisting of a hydrogen atom, halogen atom, alkyl, alkoxy, alkylthio, aryloxy, and arylthio radical, R.sub.21 and R.sub.22, R.sub.22 and R.sub.23, R.sub.23 and R.sub.24, R.sub.25 and R.sub.26, R.sub.26, and R.sub.27, R.sub.27 and R.sub.28, R.sub.29 and R.sub.30, R.sub.30 and R.sub.31, R.sub.31 and R.sub.32, taken together, each may form a fused ring, and
- X is selected from the group consisting of a halogen atom, hydroxyl, alkoxy, phenoxy and phenyl radical, and
- the recording layer A is formed on the recording layer B with an intermediate layer interleaved therebetween.
Dependencies are inferred from the claim text.