JPH09323478A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain excellent recording and reproducing characteristics in a specific wavelength by forming a recording layer from a material containing metal-containing azo compound represented by a specific formula in an optical recording medium obtained by sequentially providing a recording layer containing dyes and a reflecting layer on a board and providing a protective film on the reflecting layer. SOLUTION: In an optical recording medium having a recording layer containing dye, a reflecting layer on the recording layer and a protective film on the reflecting layer on a board, the recording layer contains metal-containing azo compound represented by a formula separately descried, where R<1> and R<2> are each nitro group, halogen atom, amino group, or sulfamoyl group, and t and u are each integer of 1 to 4, R<3> and R<4> are each halogen atom, nitro group or alkyl group, v and w are each integer of 1 to 6, M<1> is cobalt or nickel, and Y<+> is alkyl substituted ammonium ion, where i, u, v and w do not simultaneously become '0' and t+u+v+w is 1 to 20.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an optical recording medium, particularly an optical recording medium capable of recording / reproducing with a red laser of 630 nm to 690 nm, or recording / reproducing with a near infrared laser of 770 nm to 830 nm and a red laser of 630 nm to 690 nm. Possible optical recording medium.

[0002]

2. Description of the Related Art The inventors of the present invention have used C as a recordable optical recording medium compatible with the CD (Compact Disc) standard.
D-R (write-once compact disc) has been developed.
In recent years, higher density optical recording media have been desired. For example, the recording wavelength of CD-R is 680 nm from the current 780 nm.
650nm, the next-generation CD-R with a shorter wavelength of 635nm
A DVD-R (write-once type video disc) capable of recording / reproducing at is mentioned. Also, in consideration of compatibility with the existing CD-R, a CD-RII has been proposed which can reproduce even at a short wavelength. The requirements for dyes used in these standards are considered to be almost the same as the requirements for existing dyes except for the wavelength. However, as a result of the progress of development to correspond to 780 nm, there are almost no known dyes satisfying various properties such as light resistance, solubility and recording sensitivity on the short wavelength side such as 680 to 635 nm. .

The recording wavelength is also important, but a particularly important and difficult property to realize is the light resistance of the dye for the recording layer. As a high light fastness dye, there is an example in which light fastness is improved by combining a metal complex quencher with a cyanine dye having low light fastness as shown in JP-A-59-55795.
However, this system has the drawback that the solubility in the coating solvent used during spin coating is significantly reduced and that the stabilizer itself is decomposed and deteriorated. Besides this,
Examples of dyes having high light resistance include azo metal complex dyes [Japanese Patent Publication No. 7-42451 (corresponding to JP-A-63-35).
No. 587) and JP-B-7-37580], and formazan nickel complex dyes (JP-A-60-254038 and JP-A-62-144997). Certainly, these metal complex dyes are excellent in light resistance, but generally have low recording sensitivity, relatively low solubility, and have the disadvantage that they are dissolved only in a specific solvent. Considering the recording and reproducing at a short wavelength of 680 to 635 nm, the absorption wavelength of the formazan nickel metal complex dye is too long, and it is considered that this skeleton cannot cope with the short wavelength.

Further, Japanese Patent Laid-Open No. 2-55189 discloses that
There is an example in which an azo metal-containing dye having absorption at 750 to 850 nm and a dye having no light resistance are mixed to improve light resistance, and such an azo metal complex is used for dyes having the above absorption wavelength. Is effective, but 630-6
For dyes having absorption at 90 nm and not having light resistance, the absorption wavelengths of the two are different, so the effect as a quencher of the azo metal complex is low, and it is not possible to form a disk for short wavelength with improved light resistance. It was

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical recording medium having excellent light resistance and excellent recording / reproducing characteristics at a wavelength selected from 630 nm to 690 nm, or a conventional optical recording medium selected from 770 nm to 830 nm. It is an object of the present invention to provide an optical recording medium having good recording characteristics, capable of recording / reproducing in conformity with the CD standard even for light of a given wavelength.

[0006]

The above object is achieved by the following items (1) to (10). (1) In an optical recording medium having a recording layer containing a dye on a substrate, a reflective layer on the recording layer, and a protective film on the reflective layer, the recording layer has the following formula (I ) An optical recording medium containing a metal-containing azo compound represented by the formula (1).

[0007]

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[In the formula (I), R ¹ and R ² each represent a nitro group, a halogen atom, an amino group, a sulfamoyl group, an alkyl group or an alkoxy group, and t and u
Are each 0 or an integer of 1 to 4. R ³ and R ⁴ represent a halogen atom, a nitro group, an alkyl group, an alkoxy group or an amino group, and v and w are 0 or 1 to 6, respectively.
Is an integer. M ¹ represents cobalt or nickel.
Y ⁺ represents an alkyl-substituted ammonium ion. However, t, u, v, and w never become 0 at the same time,
t + u + v + w is 1 to 20. (2) The optical recording medium according to (1) above, wherein the recording layer contains a trimethinecyanine dye represented by the following formula (II).

[0009]

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[In the formula (II), Q ₁ and Q ₂ represent a group of atoms necessary for completing a heterocycle with a carbon atom and a nitrogen atom, respectively, and the heterocyclic skeleton completed by Q ₁ or Q ₂ May be the same or different. R ₁ and R ₂ each represent an aliphatic hydrocarbon group, which may be the same or different. R ₃ represents a hydrogen atom or a monovalent substituent. X ⁻ represents a monovalent anion. (3) A second layer in which the recording layer has different optical characteristics from the metal-containing azo compound or the trimethine cyanine dye.
The optical recording medium of (1) or (2) above, which contains the light-absorbing dye of 1) and performs recording / reproduction with light having a first wavelength of 630 to 690 nm and light having a second wavelength of 770 to 830 nm. (4) The optical recording medium according to (3), wherein recording is performed with the second wavelength light, and reproduction is performed with the first and second wavelength lights. (5) The real part n of the complex refractive index at 650 nm of the metal-containing azo compound and the trimethine cyanine dye is 1.8 to 2.6, and the imaginary part k is 0.02 to 0.20. ,
The real part n of the complex index of refraction at 780 nm of the second light absorbing dye is 1.8 to 2.6, the imaginary part k is 0.02 to 0.30, and the full width at half maximum of the absorption spectrum of the thin film is The optical recording medium of (3) above, wherein the recording layer having a thickness of 170 nm or less is provided on a substrate. (6) In the first recording layer containing the metal-containing azo compound or the compound and the trimethine cyanine dye, the second recording layer containing the second light absorbing dye having different optical characteristics from those of the compound is contained. The optical recording medium according to the above (1) or (2), wherein recording layers are laminated to form two or more recording layers. (7) The real part n of the complex refractive index at 650 nm of the metal-containing azo compound or the trimethine cyanine dye is 1.8 to 2.6, and the imaginary part k is 0.02 to 0.20,
The real part n of the complex index of refraction of the second light absorbing dye at 780 nm is 1.8 to 2.6, the imaginary part k is 0.02 to 0.15, and the full width at half maximum of the absorption spectrum of the thin film is The optical recording medium of (6) above, which has a thickness of 170 nm or less and which has two or more recording layers provided on a substrate. (8) The optical recording medium according to the above (6) or (7), wherein a first recording layer is provided on a substrate, and a second recording layer is provided on the first recording layer. (9) The optical recording medium according to any one of (3) to (8) above, wherein the second light absorbing dye is a phthalocyanine dye represented by the following formula (III).

[0011]

[Chemical 6]

[In the formula (III), M represents a central atom. X ₁ , X ₂ , X ₃ and X ₄ each represent a halogen, which may be the same or different. p
1, p2, p3 and p4 are each 0 or an integer of 1 to 4, and p1 + p2 + p3 + p4 is 0 to 15. Y
₁ , Y ₂ , Y ₃ and Y ₄ each represent an oxygen atom or a sulfur atom, which may be the same or different. Z ₁ , Z ₂ , Z ₃ and Z ₄ each have 4 carbon atoms
The above alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and heterocyclic groups are the same or different. q1, q2, q3 and q4 are each 0
Or an integer of 1 to 4, which are not simultaneously 0, and q1 + q2 + q3 + q4 is 1 to 8. (10) The film thickness of each of the first recording layer and the second recording layer is 20 to 250 nm, and the film thickness of the first recording layer is divided by the film thickness of the second recording layer. The optical recording medium of (8) or (9) above, which has a value of 0.1 to 1. In addition, Japanese Patent Publication No. 7-37580 and Japanese Patent Publication No. 7-42451 (corresponding to JP-A-63-35587) disclose structures similar to those of the metal-containing azo compound represented by the formula (I) of the present invention. It has been disclosed that a compound having a is used for a recording layer of an optical recording medium. However, the compound disclosed in JP-B-7-37580 is different from the compound of the present invention in that the central metal is Cr and the counter cation is a quaternary pyridinium derivative. The compound disclosed in Japanese Examined Patent Publication No. 7-42451 (corresponding to JP-A-63-35587) has two or more complex anions, and the counter cation is a polyvalent metal ion having a valence of 2 or more. , Different from the compounds of the present invention. In addition, Japanese Patent Laid-Open No. 2-5
Japanese Patent No. 5189 discloses compounds overlapping with the compound of the present invention, and it is shown that these compounds are used in a recording layer of an optical recording medium. No specific compound as a counter cation is presented.
Further, all the optical recording media disclosed in the above publications are compatible with recording / reproducing wavelengths of about 750 to 850 nm, and are not compatible with short wavelength recording.

[0013]

Embodiments of the present invention will be described below in detail.

The optical recording medium of the present invention has a recording layer of the formula (I)
It contains a metal-containing azo compound represented by [Chemical Formula 4].

Explaining formula (I), in formula (I), R ¹ and R ² each represent a nitro group, a halogen atom, an amino group, a sulfamoyl group, an alkyl group or an alkoxy group.

Examples of the halogen atom represented by R ¹ and R ² include F, Cl, Br and I.

The amino group represented by R ¹ and R ² is
It may have a substituent such as an alkyl group, an alkoxy group and an acyl group, and these substituents may be substituted with a halogen atom (Cl, Br, I etc.), a hydroxy group, an alkoxy group and the like. . Specific examples of the amino group represented by R ¹ and R ² include an amino group, a methylamino group,
Examples thereof include a dimethylamino group, an acetylamino group and a benzylamino group. The total carbon number of such amino groups is preferably 0-8.

The sulfamoyl group represented by R ¹ and R ² may have a substituent such as an alkyl group or an alkoxy group, and these substituents may be a halogen atom (Cl, Br, I, etc.). ), A hydroxy group, an alkoxy group or the like. As the sulfamoyl group represented by R ¹ and R ² , specifically, a sulfamoyl group,
N-methylsulfamoyl group, N, N-dimethylsulfamoyl group, N, N-diethylsulfamoyl group, N,
N-methylhydroxyethylsulfamoyl group, N, N
Examples include -methoxyethylsulfamoyl group and N-methoxyethylsulfamoyl group. The total carbon number of such a sulfamoyl group is preferably 0-10.

The alkyl group represented by R ¹ and R ² is preferably an alkyl group having 1 to 4 carbon atoms, which may be linear or branched and may have a substituent (for example, a halogen atom). , An alkoxy group, etc.), specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group,
Examples thereof include t-butyl group and methoxyethyl group.

The alkoxy group represented by R ¹ and R ² preferably has an alkyl moiety having 1 to 4 carbon atoms,
It may have a substituent (for example, a halogen atom etc.),
Specific examples include a methoxy group and an ethoxy group.

In the formula (I), R ³ and R ⁴ each represent a halogen atom, a nitro group, an alkyl group, an alkoxy group or an amino group.

The halogen atom, alkyl group, alkoxy group and amino group represented by R ³ and R ⁴ include R ¹ and R ²
The same as the above can be mentioned.

T and u are each 0 or an integer of 1 to 4, v and w are each 0 or an integer of 1 to 6,
These do not become 0 at the same time, and t + u + v + w is 1 to 20. Moreover, when t, u, v, and w are integers of 2 or more, R ^{1 s} , R ^{2 s} , R ^{3 s} , and R ^{4 s} may be the same or different. Under such conditions, t and u are preferably 0, 1 or 2, and v and w are preferably 0 or 1. Further, it is preferable that t = u and v = w, and the two benzene rings, the presence or absence of a substituent in the two naphthalene rings, the kind, position and number of the substituents in the case of having a substituent are the same. Preferably there is.

In the present invention, in the formula (I), t,
u is an integer of 1 or more, electron-withdrawing groups such as nitro groups are present as R ¹ and R ² , and v and w are integers of 1 or more, and amino groups are R ³ and R ^4. It is preferable not to take a combination of substituents such that an electron-donating group such as

In the formula (I), M ¹ is Co or Ni
And Co is particularly preferable.

In the formula (I), Y ⁺ represents an alkyl-substituted ammonium ion. The alkyl moiety in the alkyl-substituted ammonium ion may be linear or branched, and further has a substituent (ether group,
(Acyloxy group, aryl group, etc.). Particularly, those having an alkyl group in which an ether bond (—O—) is interposed are preferable. The total number of carbon atoms in the alkyl-substituted ammonium ion is 4 to 2
It is preferably 1.

Specific examples of the alkyl-substituted ammonium ion represented by Y ⁺ include the following.

[0028]

[Chemical 7]

Specific examples of the metal-containing azo compound represented by the formula (I) used in the present invention are shown below, but the present invention is not limited thereto. In the following, the formula (I-1)
Shows a combination of display, Y ⁺ is the illustrated Y ₁ ⁺ -
1 and the like, when all of R _{11 to} R _{14 and the} like are H, it is H, and when it is a substituent, only the substituent is shown and the indication of H is omitted.

[0030]

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[0031]

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[0032]

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[0033]

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These metal-containing azo compounds are known in the literature [eg, JP-A-50-39328 and JP-A-55].
-151061 (corresponding West German Patent Publication 2918634)
No.), West German Patent 1260652, West German Patent 12267
No. 27, etc.].

The melting point (mp) of the metal-containing azo compound represented by the formula (I) is 100 to 300 ° C., and λ _max (50
measured with a dye thin film of nm thickness) is in the range of 500 to 650 nm.

These metal-containing azo compounds can be used as a dye for the recording layer, and may be used alone or in combination of two or more.

Further, in these dyes, the real part n of the complex refractive index at 650 nm is 1.8 to 2.6 and the imaginary part k is 0 to 0.3.
0.

For the dyes n and k, a dye film is formed on a predetermined transparent substrate under the same conditions as the recording layer to a thickness of the recording layer of the optical recording medium, for example, about 40 to 100 nm. To prepare a measurement sample, and then measure the reflectance and transmittance at 650 nm of the measurement sample,
From these measured values, for example, it is calculated in accordance with Kyoritsu Zensho "Optical" Kozo Ishiguro P168-178. The reflectance is the reflectance of the measurement sample through the substrate or the reflectance from the dye film side, and is measured by specular reflection (about 5 °).

These compounds have sufficient solubility in an organic solvent and have a large solubility in a coating solvent that does not attack a polycarbonate resin (PC) which is widely used as a substrate material for optical recording media.

The recording layer using these compounds is particularly preferably used for a write-once type optical recording disk (CD-R), and recording / reproducing at a short wavelength becomes possible. Such a recording layer is preferably formed using a dye-containing coating solution. Particularly, it is preferable to use the spin coating method in which the coating liquid is spread and coated on the rotating substrate. In addition, gravure coating, spray coating, dipping or the like may be used. The coating solvent used at this time will be described later.

After spin coating as described above, the coating film is dried if necessary. The thickness of the recording layer thus formed is appropriately set according to the desired reflectance and the like, but is usually 500 to 3000 A.

The dye content of the coating liquid is preferably 0.05 to 10 wt%. Since the dye of the metal-containing azo compound has good solubility, a coating liquid having such a content can be easily prepared. Specifically, the dye of the metal-containing azo compound of the present invention shows good solubility mainly in polar solvents, and alcohols, cellosolves or alkoxy alcohols, keto alcohols such as diacetone alcohol, and ketones such as cyclohexanone. 0.5 to 10 wt% is dissolved in fluorinated alcohol such as 2,2,3,3-tetrafluoropropanol. Ethyl cellosolve and 2,2, which are suitable coating solvents especially when applied to a polycarbonate disc,
Dissolving 4 wt% or more in 3,3-tetrafluoropropanol, it is possible to form a good quality spin coat film in a short time.

The coating liquid may appropriately contain a binder, a dispersant, a stabilizer and the like.

In addition to the metal-containing azo compound, the recording layer of the optical recording medium of the present invention may contain other kinds of light absorbing dyes. Examples of such a dye include a phthalocyanine dye, a cyanine dye, a metal complex dye different from the above, a styryl dye, a porphyrin dye, an azo dye different from the above, and a formazan metal complex.

Therefore, in such a case, the recording layer may be coated by including such a dye in the coating liquid.

The metal-containing azo compound of the present invention can be used as a singlet oxygen quencher because of its excellent singlet oxygen quenching ability, and is mixed with a dye having low light resistance such as a cyanine dye. Has the effect of improving the light resistance of the dye. In particular, in the case of a dye having a low light resistance having an absorption in a short wavelength of about 680 to 550 nm, the light absorption is the same as that of the metal-containing azo compound of the present invention, and therefore the light resistance is not changed without changing the reflectance of the dye itself. Only can improve.

Especially as such a dye on the short wavelength side,
The trimethine cyanine dye represented by the formula (II) [shown in Chemical Formula 5] is desirable, and the molar ratio of the mixture is such that the metal-containing azo compound / trimethine cyanine dye = 10/90.
˜95 / 5 is desirable.

The formula (II) will be described below.
Wherein Q ₁ and Q ₂ represent an atomic group necessary for completing a heterocycle with a carbon atom and a nitrogen atom, respectively, and the heterocyclic skeleton completed by Q ₁ or Q ₂ may be the same or different. Although good, it is preferable that they have the same skeleton in terms of synthesis. Such a heterocyclic skeleton is preferably a benzothiazole skeleton, a thiazole skeleton, an oxazole skeleton,
Examples thereof include a benzoxazole skeleton, a pyridine skeleton, a quinoline skeleton, an imidazole skeleton, an indolenine skeleton, a benzoindolenine skeleton, and a dibenzoindolenin skeleton.

The heterocyclic ring completed by Q ₁ or Q ₂ may have a substituent, and such a substituent includes a halogen atom, an alkyl group, an aryl group, an acyl group, an amino group and the like. .

R ₁ and R ₂ each represent an aliphatic hydrocarbon group, which may be the same or different. Examples of the aliphatic hydrocarbon group include an alkyl group and a cycloalkyl group. The alkyl group has 1 to 4 carbon atoms.
Are preferred, methyl group, ethyl group, propyl group,
Butyl group etc. Moreover, a cyclohexyl group etc. are mentioned as a cycloalkyl group. This compound may have a substituent, and examples of the substituent include a halogen atom, an ether group such as an alkyl group, an aryl group, an alkoxy group, an ester group, and a heterocyclic group. Of these, an unsubstituted alkyl group is preferable, and particularly a methyl group,
Ethyl group, butyl group and the like are preferable. From the viewpoint of solubility in a specific coating solvent such as ethyl cellosolve, an alkoxyalkyl group having an ether bond, etc., preferably an alkoxyalkyl group having a total carbon number of 3 to 6 is preferable.

R ₃ represents a hydrogen atom or a monovalent substituent. As the monovalent substituent, an alkyl group, an aryl group,
Examples thereof include an azo group, an ester group, an acyl group, a halogen atom and a heterocyclic group, and among these monovalent groups, an alkyl group, an aryl group, an azo group, an ester group, an acyl group and a heterocyclic group may have a substituent. You may have. When it has a substituent, examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, an amino group, a heterocyclic group and a nitro group.

X ⁻ represents a monovalent anion, ClO ₄ ⁻ ,
Examples thereof include I ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , and paratoluenesulfonate ion.

Among the trimethine cyanine dyes represented by the formula (II), the trimethine indolenine cyanine dye represented by the following formula (II-1) is preferable.

[0054]

[Chemical 12]

The formula (II-1) will be explained. In the formula (II-1), Q ₃ and Q ₄ each represent an atom group necessary for completing an indolenine ring or a benzoindolenine ring together with a pyrrole ring. , Q ₃ or Q ₄ may be the same or different rings. Moreover, such an indolenine ring or a benzoindolenine ring may have a substituent, and such a substituent includes a halogen atom, an alkyl group, an aryl group, an acyl group, an amino group, and the like.

When the ring completed by Q ₃ or Q ₄ is a benzoindolenine ring, the position of condensation of the benzene ring with respect to the indolenine ring is not particularly limited, but benzene is present at the 4- and 5-positions of the indolenine ring. It is preferable that the rings are condensed (see the following formula (II-1a): Chemical formula 13).

In particular, in the case of 630 to 640 nm, Q
_{A combination in which one of 3} , Q ₄ is an indolenine ring and the other is a benzoindolenine ring is preferable, and a combination of more than 640 to 680
In the case of nm correspondence, a combination in which both Q ₃ and Q ₄ are benzoindolenin rings is preferable.

R ₃ represents a hydrogen atom or a monovalent substituent and has the same meaning as R _{3 in} formula (II). R ₃ is preferably a hydrogen atom.

R ₄ and R ₅ each represent an alkyl group.
The alkyl group may have a substituent and preferably has 1 to 4 carbon atoms. Examples of the substituent include the same substituents as R ₁ and R _2. Especially, alkoxy and the like are preferable. The alkyl group represented by R ₄ and R ₅ is a methyl group, an ethyl group, or (n
Examples include-, i-) propyl group, (n-, i-, s-, t-) butyl group, methoxymethyl group, methoxyethyl group and ethoxyethyl group.

An unsubstituted alkyl group as R ₄ and R ₅ ,
An alkoxyalkyl group or the like is preferable, and in the sense that the solubility in a specific coating solvent such as ethyl cellosolve is improved, at least one of R ₄ and R ₅ is an alkoxyalkyl group, preferably a total carbon number of 3 to 6 It is preferably an alkoxyalkyl group.

[0061] X ^- represents an anion, X of formula (II) ^- is of the same meaning.

Among the trimethine indolenine type cyanine dyes represented by the formula (II-1), the following formulas (II-1a) and (II-1
Those represented by b) are preferred.

[0063]

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[0064]

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In formulas (II-1a) and (II-1b), R ₁₁ and R
₁₂ is of R ₄ and R ₅ as defined in each formula (II-1), R ₃ is of the same meaning as R ₃ in formula (II-1), preferably a hydrogen atom, X ^- the X of formula (II-1) ^- is of the same meaning. In formula (II-1a), R ₁₃ represents a hydrogen atom, a halogen atom or an alkyl group, preferably an alkyl group having 1 to 4 carbon atoms.

In the formulas (II-1a) and (II-1b), the indolenine ring and the benzoindolenine ring each have a halogen atom, an alkyl group, an aryl group, an acyl group or an amino group in addition to the above R _13. May have a substituent such as.

R ₁₁ in formulas (II-1a) and (II-1b)
And R ₁₂ is preferably an unsubstituted alkyl group, an alkoxyalkyl group or the like, and from the viewpoint of improving the solubility in a specific coating solvent such as ethyl cellosolve and obtaining a coating film with good properties, either or Both are preferably an alkoxyalkyl group, and specific examples thereof include a methoxymethyl group, a methoxyethyl group, an ethoxyethyl group and the like as in the case of the formula (II-1). The alkoxyalkyl group preferably has 3 to 6 carbon atoms in total.

Specific examples of the trimethinecyanine dye of formula (II) used in the present invention are shown below, but the present invention is not limited thereto.

[0069]

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[0070]

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[0071]

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[0072]

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[0073]

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[0074]

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[0075]

[Chemical 21]

These trimethine cyanine dyes may be used alone or in combination of two or more. The λ max of the trimethine cyanine dye (measured with a dye thin film having a thickness of 80 nm) is 560 to 620 nm, and its melting point (mp) is 100 to
300 ° C.

Tables 1 and 2 show λmax of these trimethine cyanine dyes and n and k at 630 nm or 650 nm obtained by setting the thickness of the dye film to 80 nm.

[0078]

[Table 1]

[0079]

[Table 2]

The dye of the formula (II) can be made more suitable for the recording and reproducing wavelengths of the short wavelength by combining these dyes with each other or using the compound of the formula (I) and the like.

In the present invention, in particular, recording / reproducing can be performed with two wavelengths of a short wavelength of about 690 to 630 nm and a conventional wavelength of about 780 nm, and recording and reproduction can be performed separately for these two wavelengths. . In this case, it is suitable for the CD-RII recording and reproducing method in which recording is performed with light having a conventional wavelength of about 780 nm, and reproduction is performed with two wavelengths of short wavelength and light having a conventional wavelength of about 780 nm. In such a structure, it is preferable to use, in addition to the metal-containing azo compound and the trimethinecyanine dye of the present invention, dyes having different optical properties such as absorption properties, that is, dyes having different optical constants in the recording layer.
In addition to the metal-containing azo compound and trimethine cyanine dye of the present invention, the absorption maximum (λ _max ) is 680 to 750 nm.
It is preferable to add a dye of a certain degree, and a dye having such an absorption maximum (λ _max ) may be selected from the above dyes and used. Of these, phthalocyanine dyes and pentamethine cyanine dyes are usually used.

In particular, when used in the recording layer of a CD-RII of the type which records and reproduces at two wavelengths as described above, the metal-containing azo compound and the trimethine cyanine dye are 650 nm.
, The real part n of the complex refractive index is 1.8 to 2.6, and the imaginary part is 0.
It is preferably from 0.2 to 0.20. On the other hand, as a dye to be combined with this, the real part n of the complex refractive index at 780 nm is 1.8 to 2.6, the imaginary part k is 0.02 to 0.30,
Especially when it is used for a laminated type recording layer, 0.02 to 0.
15, the full width at half maximum of the absorption spectrum of the thin film, that is, the full width at half maximum of λmax is 170 nm or less,
It is preferably 150 nm or less. The lower limit of the full width at half maximum is not particularly limited, but is usually 50 nm. By using such a half width, the absorption characteristics of the metal-containing azo compound and the trimethine cyanine dye used in combination are not affected, and the reflectance and the degree of modulation in the short wavelength region are sufficient. In contrast, the half width is 1
If the wavelength exceeds 70 nm, the absorption edge is applied to the wavelength region of the short wavelength laser, and the reflectance in the short wavelength region is reduced. The half value width was determined by preparing a sample in which a dye film was formed on a transparent substrate so that the transmittance T at the absorption maximum λmax was 25% or less, and measuring the absorption spectrum of this sample. For example, to explain according to the absorption spectrum of FIG. 1, the transmittance T _{1 at} λmax and the transmittance T ₂ which becomes substantially constant without depending on the shift of the wavelength when the wavelength is shifted to the longer wavelength side are obtained. T ₂ and the bottom of the depth of half the width △ lambda half width of up to T ₁ as baseline (base). The thickness of the dye film of the sample is usually about 50 to 150 nm.

The above n and k are obtained in the same manner as above with the measurement wavelengths being 650 nm and 780 nm, respectively.

Examples of such dyes include those of the formula (III)
The phthalocyanine dye represented by [Chemical Formula 6] is preferable.

Regarding formula (III), in formula (III), M represents a central atom. The central atom represented by M includes a hydrogen atom (2H) or a metal atom. As the metal atom at this time, the periodic table groups 1 to 14 (1A to
It may be a metal atom belonging to 7A group, 8 group, 1B-4B group), and specifically, Li, Na, K, Mg, Ca, B.
a, Ti, Zr, V, Nb, Ta, Cr, Mo, W, M
n, Tc, Fe, Co, Ni, Ru, Rh, Pd, O
s, Ir, Pt, Cu, Ag, Au, Zn, Cd, H
g, Al, In, Tl, Si, Ge, Sn, Pb, etc., especially Li, Na, K, Mg, Ca, Ba, Ti, Zr,
V, Nb, Ta, Cr, Mo, W, Mn, Tc, Fe,
Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, C
u, Ag, Au, Cd, Hg, Al, In, Tl, S
Examples thereof include i, Ge, Sn, and Pb. Among these, A
l, Si, Ge, Sn, Cu, Pd, Ni, Fe, Co
Etc. are preferable, and particularly Cu, Pd, Ni, Fe, Co, V
O and the like are preferable in terms of stability over time.

These metal atoms may be in the form of VO in which O is coordinated, such as V, and further, such as Si, Al, Ge, Co, Fe, etc. A ligand such as an ether group, an ester group, pyridine and a derivative thereof may be further coordinated to the upper and lower sides or one side of the above.

X _{1 to} X ₄ each represent a halogen atom,
The halogen atom includes F, Cl, Br, I and the like. Particularly, Br and F are preferable.

P1, p2, p3 and p4 are each 0 or an integer of 1 to 4, and p1 + p2 + p3 + p4 is 0 to
15 and preferably 0 to 10.

X _{1 to} X ₄ may be the same or different, and when p1, p2, p3 and p4 are each an integer of 2 or more, X _1's , X _2's , X _3's , X ₄
They may be the same or different.

Y _{1 to} Y ₄ each represent an oxygen atom or a sulfur atom, and particularly preferably an oxygen atom. Y _{1 to} Y
₄ are usually the same, but may be different. Z
_{1 to} Z ₄ each represent an alkyl group having 4 or more carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group,
These may be the same or different.

Each of q1, q2, q3 and q4 is 0 or an integer of 1 to 4, and these are not 0 at the same time, and q1 + q2 + q3 + q4 is 1 to 8, preferably 2 to 6.

The bonding position of Y _{1 to} Y ₄ with respect to the phthalocyanine ring is preferably the 3-position and / or the 6-position (see the following structural formula) of the phthalocyanine ring, and it is preferable that at least one such bond is contained. .

[0093]

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The alkyl group represented by Z _{1 to} Z ₄ preferably has 4 to 16 carbon atoms, and may be linear or branched, but may be branched. preferable. It may have a substituent, and examples of the substituent include a halogen atom (F, Cl, Br, I, etc., particularly preferably F, Br, etc.) and the like. Specific examples of such alkyl _{groups, n-C 4 H 9,} i-C 4 H
_{9 -, s-C 4 H} 9 -, t-C 4 H 9 -, n-C 5 H 11
_{-, (CH 3) 2 CHCH} 2 CH 2 -, (CH 3) 3 C
_{CH 2 -, (C 2 H} 5) 2 CH-, C 2 H 5 C (CH
_{3) 2 -, n-C} 3 H 7 CH (CH 3) -, n-C 6 H
_{13 -, (CH 3) 2} CHCH 2 CH 2 CH 2 -, (CH
_{3) 3 C-CH 2 -CH} 2 -, n-C 3 H 7 CH (CH
_{3) CH 2 -, n-} C 4 H 9 CH (CH 3) -, n-C 7
_{H 15 -, [(CH 3} ) 2 CH] 2 -CH-, n-C 4 H
_{9 CH (CH 3) CH 2} -, (CH 3) 2 CHCH 2 C
_{H (CH 3) CH 2 -} , n-C 8 H 17 -, (CH 3) 3
_{CCH 2 CH (CH 3) CH} 2 -, (CH 3) 2 CHC
_{H (i-C 4 H 9} ) -, n-C 4 H 9 CH (C 2 H 5)
_{CH 2 -, n-C 9} H 19 -, CH 3 CH 2 CH (CH
_{3) CH 2 CH (CH 3} ) CH 2 CH 2 -, (CH 3)
_{2 CHCH 2 CH 2 CH 2 CH} (CH 3) CH 2 -, n
_{-C 3 H 7 CH (CH 3} ) CH 2 CH (CH 3) CH 2
_{-, n-C 10 H 21} -, (CH 3) 3 CCH 2 CH 2 C
_{(CH 3) 2 CH 2 -} , n-C 11 H 23 -, n-C 12 H 25
_{-, n-C 13 H 27} -, n-C 14 H 29 -, n-C 15 H
_{31 -, n-C 16 H} 33 -, n-C 4 F 9 -, i-C 4 F 9
_{-, s-C 4 F 9} -, t-C 4 F 9 - , and the like.

Examples of the alicyclic hydrocarbon group represented by Z _{1 to} Z ₄ include a cyclohexyl group and a cyclopentyl group, with a cyclohexyl group being preferred. These may further have a substituent, and examples of such a substituent include an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an aralkyl group, a halogen atom, a nitro group, a carboxyl group, an ester group, and an acyl group. Group, amino group, amido group, carbamoyl group, sulfonyl group, sulfamoyl group, sulfo group, sulfino group, arylazo group, alkylthio group, arylthio group, and the like, and among them, an alkyl group having 1 to 5 carbon atoms (for example, methyl group). Group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-
Butyl group, n-pentyl group, iso-pentyl group, ne
o-pentyl group, tert-pentyl group, 1-methylbutyl group), alkoxy group (for example, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group), Aryl group (eg phenyl group, tolyl group, biphenyl group, naphthyl group), halogen atom (eg F,
Cl, Br, I, preferably F, Br) and the like are preferable.
The substitution position of these substituents is preferably one or both of the adjacent positions of the bonding positions of Y _{1 to} Y ₄ , and preferably at least one such substitution is included.

The aromatic hydrocarbon group represented by Z _{1 to} Z ₄ may be a monocyclic ring or a condensed ring, and may further have a substituent. The total number of carbon atoms is preferably 6-20. Specific examples thereof include a phenyl group and a naphthyl group, and a phenyl group is preferable. These may further have a substituent, and examples of such a substituent include those similar to those exemplified in the alicyclic hydrocarbon group, and the preferable ones are also the same. The preferred substitution position is also the same, and it is preferably the ortho position of the bonding position of Y _{1 to} Y ₄ , and preferably at least one ortho substitution is included.

The heterocyclic group represented by Z _{1 to} Z ₄ is
It may be a monocyclic ring or a condensed ring, and the hetero atom is preferably oxygen, nitrogen, sulfur or the like, particularly oxygen, nitrogen or the like. Specific examples thereof include a pyridyl group, a furanone-yl group, a pyrazyl group, a pyrazolidyl group, a piperidinone-yl group, a quinoxalyl group, a pyranone-yl group, and a thiophentrione-yl group, and a pyridyl group, 2-
A furanone-yl group is preferred. These heterocyclic groups are
Further, it may have a substituent, and examples of the substituent include those exemplified for the alicyclic hydrocarbon group and aromatic hydrocarbon group, and the preferable ones are also the same. In particular, when a carbon atom is present at a position adjacent to the bonding position of Y _{1 to} Y ₄ , it is preferable to have a substituent at such a position.

As Z _{1 to} Z ₄ , an alicyclic hydrocarbon group and an aromatic hydrocarbon group are particularly preferable, a cyclohexyl group and a phenyl group are more preferable, and at least one of the bonding positions of Y ₁ to Y ₄ is particularly preferable. Those having a substituent (particularly the above-mentioned preferred substituent) at the position adjacent to are preferable.

Specific examples of such phthalocyanine dyes are shown below, but the present invention is not limited thereto. Specific examples are X _{11 to} X ₁₄ and X ₁₅ to X ₁₅ of the following formula (III-1).
X ₁₈ , X _{19 to} X ₂₂ , X _{23 to} X _26, and M are used to represent, and when X _{11 to} X _{14 and the} like are all H, H
In addition, when it is a substituent, only H is shown and the symbol H is omitted. In addition, 3 in the phthalocyanine ring
The 6-position, the 4-position, the 4-position and the 5-position are equivalent to each other, and when a substituent is present in any one of these positions, they are only representative examples.

[0100]

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[0101]

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[0102]

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[0103]

[Chemical formula 26]

[0104]

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[0105]

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[0106]

[Chemical 29]

[0107]

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[0108]

[Chemical 31]

[0109]

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[0110]

[Chemical 33]

[0111]

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[0112]

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[0113]

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[0114]

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These phthalocyanine dyes are described in JP-A-63-313760, JP-A-63-301261,
The compound can be synthesized with reference to the method described in EP 675489 and the like.

The melting point (mp) of these dyes is 60-40.
0 ° C

780 nm of these phthalocyanine dyes
Are shown in Tables 1 and 2. These n and k are obtained by setting the thickness of the dye film to 80 nm. Further, the half width of the absorption spectrum of the dye thin film was determined as described above, and these results and λmax (thin film) are also shown.

[0118]

[Table 3]

[0119]

[Table 4] These dyes may be used alone or in combination of two or more.

Specific examples of the coating solvent used in the present invention include alcohols (including keto alcohols and alkoxy alcohols such as ethylene glycol monoalkyl ethers), aliphatic hydrocarbons, ketones, and esters. It may be appropriately selected from a system, an ether system, an aromatic system, an alkyl halide system and the like.

Of these, alcohol type and aliphatic hydrocarbon type are preferable. Among alcohols, alkoxy alcohols and keto alcohols are preferred.
In the alkoxy alcohol system, the alkoxy moiety preferably has 1 to 4 carbon atoms, and the alcohol moiety has 1 to 5 carbon atoms, more preferably 2 to 5 carbon atoms, and the total carbon atom is 3 To 7 is preferable.
Specifically, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (also referred to as ethyl cellosolve, ethoxyethanol), butyl cellosolve, 2-isopropoxy-1-
Ethylene glycol monoalkyl ether (cellosolve) such as ethanol, 1-methoxy-2-propanol, 1-methoxy-2-butanol, 3-methoxy-1
-Butanol, 4-methoxy-1-butanol, 1-ethoxy-2-propanol and the like. Examples of keto alcohol-based compounds include diacetone alcohol.
Further, a fluorinated alcohol such as 2,2,3,3-tetrafluoropropanol can also be used.

Examples of the aliphatic hydrocarbon system are n-hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, dimethylcyclohexane, n-octane, iso-propylcyclohexane,
T-butylcyclohexane and the like are preferable, and among them, ethylcyclohexane and dimethylcyclohexane are preferable.

Further, examples of the ketone system include cyclohexanone.

In the present invention, an alkoxy alcohol type such as ethylene glycol monoalkyl ether type is particularly preferable, and among them, ethylene glycol monoethyl ether, 1-methoxy-2-propanol, 1-methoxy-
2-Butanol and the like are preferable, and a mixed solvent thereof is also preferable, and examples thereof include a combination of ethylene glycol monoethyl ether and 1-methoxy-2-butanol.

Incidentally, the metal-containing azo compound, the trimethinecyanine dye, and the phthalocyanine dye used in combination with these dyes may be used in combination of two or more so as to satisfy each of the above-mentioned n and k. Good.

When the recording layer of an optical recording medium for recording / reproducing at two wavelengths is used as a mixture of two or more kinds, a metal-containing azo compound or a trimethinecyanine dye and a phthalocyanine dye of the present invention are used. And other dyes, the metal-containing azo compound of the present invention, or the molar ratio of the metal-containing azo compound to the trimethine cyanine dye / other dyes is 90/10.
It is preferably from 10/90.

Therefore, such a mixed type recording layer may be coated by using a coating liquid containing such a dye in a predetermined ratio.

For the purpose of recording / reproducing at two wavelengths, the metal-containing azo compound of the present invention or a recording layer obtained by laminating the metal-containing azo compound of the present invention with a layer of a trimethine cyanine dye and another dye is also used. Good. The order of stacking may be appropriately selected, and the thickness per layer is usually about 20 to 250 nm. Such a laminated type recording layer may be coated by using a coating liquid containing each dye.

When the recording layer of such a laminated type has a two-layer structure, a recording layer corresponding to a short wavelength containing the metal-containing azo compound of the formula (I) or the trimethinecyanine dye on the substrate side. 780 nm containing a lower layer (first recording layer) on which a phthalocyanine dye of formula (II) is contained
It is preferable to provide a corresponding recording layer upper layer (second recording layer). In this case, the lower layer of the recording layer is preferably thinner than the upper layer of the recording layer, and the thickness ratio of the lower layer of the recording layer and the upper layer is preferably 1/10 to 1/1 of the lower layer / upper layer.

An optical recording disk having such a recording layer for two wavelengths or for a short wavelength on a substrate,
FIG. 2 shows an example of the configuration. FIG. 2 is a partial sectional view. The optical recording disc 1 shown in FIG. 2 is a contact type optical recording disc which has a reflective layer in close contact with the recording layer and which is capable of reproduction in accordance with the CD standard. As shown in the figure, the optical recording disc 1 has a recording layer 3 containing a dye of a metal-containing azo compound of the present invention on the surface of a substrate 2, and is in close contact with the recording layer 3 to form a reflective layer 4 and a protective film 5. Have.

The recording layer 3 is of the above-mentioned mixed type or laminated type, which is compatible with two wavelengths, and which is compatible with short wavelengths, which contains a metal-containing azo compound and a trimethine cyanine dye as main components.

The substrate 2 has a disk shape, and in order to enable recording and reproduction from the back side of the substrate 2,
Recording light and reproducing light (wavelength about 500 to 900 nm, especially wavelength about 500 to 700 nm, and further wavelength 630)
˜690 nm, especially laser light with wavelength of 635-680 nm and laser light with wavelength of 680-900 nm, laser light with wavelength of 680-780 nm and wavelength of 770-900 nm, especially 770-830 nm
Semiconductor laser light, especially 650nm and 780n
It is preferable to use a resin or glass that is substantially transparent (preferably a transmittance of 88% or more) to m).
The size is about 64 to 200 mm in diameter and 1.2 in thickness.
It should be about mm.

Grooves 23 for tracking are formed on the surface of the substrate 2 on which the recording layer 3 is formed, as shown in FIG.
The groove 23 is preferably a spiral continuous groove having a depth of 0.1 to 0.25 μm, a width of a mixed type, and a short wavelength type of 0.35 to 0.60 μm.
It is preferable that the laminated type has a groove pitch of 0.35 to 0.80 μm and a groove pitch of 1.5 to 1.7 μm. With such a configuration of the groove, a good tracking signal can be obtained without lowering the reflection level of the groove. Especially the groove width is 0.35-0.80
It is important to regulate to μm, or 0.35 to 0.60 μm, and if the groove width is less than 0.35 μm, it is difficult to obtain a tracking signal of sufficient magnitude.
With a slight offset of tracking during recording,
Jitter tends to be large. Also, as the groove width increases, waveform distortion tends to occur.

As the material of the substrate 2, it is preferable to use resin, and various thermoplastic resins such as polycarbonate resin, acrylic resin, amorphous polyolefin, TPX, polystyrene resin are suitable. And it can manufacture according to well-known methods, such as injection molding, using such a resin. The groove 23 is preferably formed when the substrate 2 is molded. After the manufacture of the substrate 2, a resin layer having the groove 23 may be formed by a 2P method or the like. In some cases, a glass substrate may be used.

As shown in FIG. 2, the recording layer 3 provided on the substrate 2 is formed by using the above-mentioned dye-containing coating liquid, preferably by the spin coating method as described above. The spin coating may be performed under normal conditions, for example, by adjusting the number of revolutions from 500 to 5000 rpm from the inner circumference to the outer circumference.

The recording layer 3 thus formed has a dry film thickness of 50 in the mixed type and the short wavelength type.
It is preferably 0 to 3000 A (50 to 300 nm). Outside of this range, the reflectivity decreases, making it difficult to perform reproduction conforming to the CD standard. At this time, groove 2
The thickness of the recording layer 3 in the recording track in 1000 is 1000A.
(100 nm) or more, particularly 1300 to 3000 A (130
.About.300 nm), the degree of modulation becomes extremely large.

In the laminated type, as described above,
Dry film thickness of 200-2500A (20-250n)
m) is preferable. As a result, good reproduction can be performed. Further, the film thickness of the recording layer 3 in the recording track in the groove 23 is 500 A (50 nm) or more, especially 50
It is preferably 0 to 800 A (50 to 80 nm).
Further, as described above, when the two-layered structure is used and the lower layer contains the dye of the metal-containing azo compound of the present invention, the thickness of the upper and lower layers is set as described above to obtain the CD-R.
In the case of II, recording / reproducing at 780 nm can be satisfactorily performed.

The recording layer 3 thus formed has 2
If the recording layer is of a wavelength-compatible dye-mixing type, then 6
N = 1.8-2.6, k = 0.02 at 50 nm
At 0.20 and 780 nm, n = 1.8 to 2.6, k =
It is preferably 0.02 to 0.30. When the recording layer is a two-wavelength type recording layer, n = 1.8 to 2.6 and k = 0.02 to 0.2 at 650 nm.
0 = 780 nm, n = 1.8 to 2.6, k = 0.0
It is preferably from 2 to 0.15. Thus, n, k
, Good recording and reproduction can be performed with two wavelengths. Especially, at the conventional wavelength of about 780 nm, recording and reproduction compatible with the Orange Book standard can be performed.

In the case of a short wavelength type of about 650 nm, the extinction coefficient (imaginary part of the complex refractive index) k at the wavelength of the recording light and the reproducing light is preferably 0 to 0.20. . If k exceeds 0.20, a sufficient reflectance cannot be obtained. The refractive index (real part of complex refractive index) n of the recording layer 3 is preferably 1.8 or more. If n is less than 1.8, the modulation degree of the signal is too small. Although the upper limit of n is not particularly limited, it is usually about 2.6 for convenience in the synthesis of the dye compound.

For the recording layers n and k, a recording layer is formed on a predetermined transparent substrate to a thickness of, for example, 40 to 100 nm under actual conditions to prepare a measurement sample, and then It is determined by measuring the reflectance of this measurement sample through the substrate or the reflectance from the recording layer side. In this case, the reflectance is measured by specular reflection (about 5 °) using the recording / reproducing light wavelength. Also, the transmittance of the sample is measured. And from these measurements, for example,
According to Kyoritsu Zensho "Optics" Kozo Ishiguro P168-178,
What is necessary is just to calculate n and k.

Note that n and k of such a recording layer are
Depending on the dye used, the values correspond to the above-mentioned n and k of each dye.

As shown in FIG. 2, on the recording layer 3,
The reflection layer 4 is provided in close contact with the substrate. As the reflective layer 4, it is preferable to use a metal or alloy having a high reflectivity such as Au, Cu, Al, or AgCu. The reflective layer 4 preferably has a thickness of 500 A or more, and may be formed by vapor deposition, sputtering or the like. The upper limit of the thickness is not particularly limited, but is preferably about 1200 A or less in consideration of cost, production operation time and the like. As a result, the reflectance of the reflective layer 4 alone is 90% or more, the reflectance through the substrate of the unrecorded portion of the medium is sufficient, and 780 of the two-wavelength compatible type is used.
At a conventional wavelength of about nm, 60% or more, especially 70% or more can be obtained.

As shown in FIG. 2, on the reflective layer 4,
A protective film 5 is provided. The protective film 5 is made of, for example, various resin materials such as an ultraviolet curable resin, and is usually 0.5 to 100 μm.
The layer may be formed to a thickness of about m. The protective film 5 may be in the form of a layer or a sheet. The protective film 5 may be formed by an ordinary method such as spin coating, gravure coating, spray coating, dipping, or the like.

To perform recording or additional recording on the optical recording disc 1 having such a structure, for example, 650 nm or 780 nm is used.
The recording light of nm is irradiated in a pulsed manner through the substrate 2 to change the light reflectance of the irradiation part. When the recording light is irradiated, the recording layer 3 absorbs the light and generates heat, and at the same time, the substrate 2 is also heated. As a result, in the vicinity of the interface between the substrate 2 and the recording layer 3, the material of the recording layer such as a dye is melted or decomposed, and pressure is applied to the interface between the recording layer 3 and the substrate 2 to deform the bottom and side walls of the groove. Sometimes.

The metal-containing azo compound of the present invention is
This can be used alone or together with a trimethine cyanine dye in the recording layer of a write-once digital video disc (DVD-R) for recording / reproducing at a short wavelength of about 635 nm.

FIG. 3 shows an example of the configuration. FIG.
FIG.

As shown in FIG. 3, the optical recording disk 10
Is an optical recording disc conforming to the DVD standard, and is formed by adhering a protective film 15 and a protective film 25 to each other with an adhesive, with a disc having the same structure as the optical recording disc 1.
Here, a thermosetting resin or the like may be used as the adhesive, and the thickness of the adhesive layer 50 is about 10 to 200 μm. In this case, the thickness of one substrate (usually a polycarbonate resin) is 0.6 mm, and the recording layer 13, the reflection layer 14 similar to FIG.
The protective film 15 is sequentially formed, and the recording layer 23, the reflective layer 24, and the protective film 2 are similarly formed on the substrate 22 having the groove 223.
5 is formed and is obtained by pasting as described above.

The substrate of this product is similar to that of the above-mentioned CD, but the depth of the groove is 600 to 2000 A, and the width is 0.
2 ~ 0.5μm, groove pitch 0.6 ~ 1.0μm
It is.

The thickness of the recording layer is 500 to 3000 A, and the complex refractive index at 635 nm is n = 1.8 to 2.
6, k = 0.02-0.20.

[0150]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention together with comparative examples.

Example 1 Metal-containing azo compound No. An optical recording disk was prepared using I-1 as a dye for the recording layer. First, a pre-groove (depth 0.08 μm, width 0.36 μm, groove pitch 0.
A recording layer containing a dye having a thickness of 2000 A (200 nm) was formed on a polycarbonate resin substrate having a diameter of 120 mm and a thickness of 0.6 mm having a thickness of 8 μm) by a spin coating method. In this case, a 2 wt% 2-ethoxyethanol solution was used as the coating liquid. Next, an Au reflecting layer having a thickness of 850 A is formed on this recording layer by a sputtering method, and a transparent protective film of ultraviolet curing acrylic resin (film thickness 5 μm is formed.
m) was formed, and the protective film was placed inside and they were bonded using an adhesive (see FIG. 3).

The disc sample No. of the optical recording disc manufactured in this way was obtained. 1 for laser (oscillation wavelength 6
(35 nm) is used to record / reproduce at a linear velocity of 2.6 m / sec to obtain optimum recording power (PO) and modulation (I11).
Mod) and reflectance (Rtop) were measured.

Further, a xenon lamp (Xenon fade meter manufactured by Shimadzu Corporation) having an 80,000 lux was irradiated for 200 hours to modulate (I11Mod) and reflectivity (Rtop).
Was measured after irradiation.

The results are shown below.

Disk sample No. It was found that the sample No. 1 had sufficiently good characteristics as a DVD and was excellent in light stability.

Example 2 An optical recording disk sample No. 2 was prepared in the same manner as in Example 1 except that the metal-containing azo compound No. I-29 was used in place of the metal-containing azo compound No. I-1. Then, when the characteristics were evaluated in the same manner, the same good result as in Example 1 was obtained.

Example 3 As a dye for optical recording layer, metal-containing azo compound No. I-1
And trimethine cyanine dye B-24 in a weight ratio of 1: 1
In the same manner as in Example 1, except that the mixture of No. 1 and No. 2 was used. 3 was formed and recording / reproducing was performed.

The results are shown below.

Disk sample No. It was found that No. 3 had sufficiently good characteristics as a DVD and was excellent in light stability. It was also found that the photodegradation of the cyanine dye is improved by using the metal-containing azo compound of the present invention.

Example 4 In Example 3, as the dye for the optical recording layer, the metal-containing azo compound No. I-1 and the trimethine cyanine dye B-2 were used.
No. 6, B-28 or B-30 was used, and three kinds of optical recording disk sample Nos. 41, 42 and 43 were similarly used.
Was manufactured, and the characteristics were evaluated in the same manner, and the same good results as in Example 3 were obtained.

Example 5 As a dye for optical recording layer, metal-containing azo compound No. I-1
And trimethine cyanine dye B-5, which were mixed in a weight ratio of compound No. I-1: cyanine dye = 7: 3, and 2-ethoxyethanol (ethyl cellosolve) was used as a coating solvent. In the same manner as in Example 1 except that a 2 wt% solution of a mixed solvent of 1: 1 and 1-methoxy-2-butanol (weight ratio) was used, a disc sample No. of the optical recording disc was prepared. 5 was formed and recording / reproducing was performed.

The results are shown below.

Disk sample No. It was found that No. 5 had sufficiently good characteristics as a DVD and was excellent in light stability. It was also found that the photodegradation of the cyanine dye is improved by using the metal-containing azo compound of the present invention.

Example 6 In Example 5, as the dye for the optical recording layer, the metal-containing azo compound No. I-1 and the trimethine cyanine dye B-
4, B-6, B-9, B-10, B-11 or B-1
When 6 kinds of optical recording disk sample Nos. 61 to 66 were prepared in the same manner except that 2 and 2 were used and the characteristics were evaluated in the same manner, the same good results as in Example 5 were obtained.

Example 7 As a dye for optical recording layer, a metal-containing azo compound No. I-
1 and a phthalocyanine dye A-3 in a weight ratio of 1: 1 were used, and the pregroove (depth 0.14 μm, width 0.50 μm, groove pitch 1.6 μm) having a diameter of 120 mm and a thickness of 1. A recording layer containing a dye is formed on a 2 mm polycarbonate resin substrate by spin coating.
It was formed to a thickness of 000 A (200 nm). In this case, a 2 wt% 2-ethoxyethanol solution was used as the coating liquid. Next, an Au reflective film having a thickness of 850 A was formed on this recording layer by a sputtering method, and a transparent protective film (film thickness 5 μm) of an ultraviolet curable acrylic resin was further formed to form a disc (see FIG. 2). ).

Compound No. I-1 has a λ _max of 610 nm when a thin film sample having a thickness of 50 nm is used, and n and k at 650 nm obtained by the above method are n = 2.1.
0 and k = 0.040.

Dye A-3 is a thin film sample having a dye film thickness of 80 nm, having λ _max = 725 nm, a half value width of 125 nm, and
n = 2.4 and k = 0.10.

The disc sample No. of the optical recording disc manufactured in this way was obtained. 7, laser (oscillation wavelength 7
Recording at a linear velocity of 1.2 m / sec using a laser (oscillation wavelength of 780 nm) and a laser (oscillation wavelength of 65 nm).
The reproduction was performed at 0 nm), and the optimum recording power (PO), modulation (I11Mod), and reflectance (Rtop) were measured.

Also, a xenon lamp (Xenon fade meter manufactured by Shimadzu Corporation) of 80,000 lux was irradiated for 200 hours, and modulation (I11Mod) and reflectance (Rtop)
Was measured after irradiation.

The results are shown below.

[0171]

Disk sample No. It was found that No. 7 had sufficiently good characteristics as CD-RII and was excellent in light stability.

Example 8 As a dye for an optical recording layer, a metal-containing azo compound No. I-
1 and cyanine dye B-5 and phthalocyanine dye A-
3 and these are compound No. 3 by weight ratio. I-1: Cyanine dye B-5: Phthalocyanine dye A-3 = 2:
Using the dye mixed at 1: 2, the coating solvent was 2-ethoxyethanol (ethyl cellosolve) and 1-methoxy-2-
1. The solvent was changed to a 1: 1 (weight ratio) mixed solvent of butanol.
In the same manner as in Example 7 except that the 25 wt% solution was used, the disk sample No. 8 is formed, recording is performed at a linear velocity of 1.2 m / sec using a laser (oscillation wavelength 780 nm), reproduction is performed with a laser (oscillation wavelength 780 nm) and laser (oscillation wavelength 650 nm), and an optimum recording power ( PO
), Modulation (I11Mod), reflectance (Rtop)
Was measured.

Also, a xenon lamp (Xenon fade meter manufactured by Shimadzu Corporation) having an 80,000 lux was irradiated for 200 hours to modulate (I11Mod) and reflectivity (Rtop).
Was measured after irradiation.

The results are shown below.

The above cyanine dye B-5 had a λ _max of 611 nm when a thin film sample having a thickness of 80 nm was used.
And n and k at 650 nm obtained by the above method were n = 2.45 and k = 0.09.

Disk sample No. It was found that No. 8 had sufficiently good characteristics as CD-RII and was excellent in light stability. It was also found that the photodegradation of the cyanine dye is improved by using the metal-containing azo compound of the present invention.

Example 9 As a dye for an optical recording layer, a metal-containing azo compound No. I-
2 and cyanine dye B-5 and phthalocyanine dye A-
3 and these are compound No. 3 by weight ratio. I-2: Cyanine dye B-5: Phthalocyanine dye A-3 = 1:
In the same manner as in Example 8 except that the dyes mixed in the ratio of 1: 2 were used, the disk sample No. 9 is formed, recording is performed at a linear velocity of 1.2 m / sec using a laser (oscillation wavelength 780 nm), reproduction is performed with a laser (oscillation wavelength 780 nm) and laser (oscillation wavelength 650 nm), and the optimum recording power ( Po), modulation (I11Mod), reflectance (R)
top) was measured.

Also, a xenon lamp (Xenon Fade Meter manufactured by Shimadzu Corporation) of 80,000 lux was irradiated for 200 hours to obtain modulation (I11Mod) and reflectance (Rtop).
Was measured after irradiation.

The results are shown below.

The above compound No. I-2 has a film thickness of 50
λ _max was 600 nm when a thin film sample of nm was used, and n and k at 650 nm obtained by the above method were n = 2.10 and k = 0.05.

Disk sample No. It was found that No. 9 had sufficiently good characteristics as CD-RII and was excellent in light stability. It was also found that the photodegradation of the cyanine dye is improved by using the metal-containing azo compound of the present invention.

Example 10 In Example 8, as the dye for the optical recording layer, the metal-containing azo compound No. I-1, cyanine dye B-5, and phthalocyanine dye A-3 were used, and these were used in a weight ratio of compound No. I-1: Cyanine dye B-5: Phthalocyanine dye A-3 = 2: 1: 6 is used as a mixture, and 2.25 wt% of these mixed dyes, 2-ethoxyethanol and 1-methoxy-2. Optical recording disk sample No. 10 was prepared in the same manner except that a solution of a mixed solvent with butanol (weight ratio 1: 1) was used, and the characteristics were evaluated in the same manner. As a result, good results similar to those of Example 8 were obtained. was gotten.

Example 11 In Example 8, as the dye for the optical recording layer, the metal-containing azo compound No. I-1, cyanine dye B-11, and phthalocyanine dye A-3 were used, and these were used in a weight ratio of compound No. I-1: Cyanine dye D-11: Optical recording disk sample No. 11 was prepared in the same manner except that a dye mixed with phthalocyanine dye A-3 = 2: 1: 2 was used. When the characteristics were evaluated, excellent results similar to those in Example 8 were obtained. The cyanine dye B-11 had a λmax of 611 nm when a thin film sample having a thickness of 80 nm was used, and n and k at 650 nm obtained by the above method were n = 2.40 and k = 0.11. It was

Further, since the cyanine dye B-11 is a compound having an alkoxyalkyl group, the solubility was better and the coating film properties were better than those of the cyanine dye B-5.

Example 12 In Example 10, as a dye for the optical recording layer, a metal-containing azo compound No. I-1, Cyanine dye B-9 and Phthalocyanine dye A-3 were used, and these were used in a weight ratio of Compound No. I-1: Cyanine dye D-9: Phthalocyanine dye A-3: An optical recording disk sample No. 12 was prepared in the same manner except that a dye mixed in a ratio of 2: 1: 2 was used. The characteristics were evaluated as in Example 8.
The same good results as those described above were obtained. The cyanine dye B-9 has a λma value of 80 nm when a thin film sample is used.
x was 613 nm, and n and k at 650 nm obtained by the above method were n = 2.40 and k = 0.12.

Further, since the cyanine dye B-9 is a compound having an alkoxyalkyl group, its solubility was better than that of the cyanine dye B-5, and the coating properties were better.

Example 13 In Example 10, as a dye for the optical recording layer, a metal-containing azo compound No. I-1, Cyanine dye B-2 and Phthalocyanine dye A-3 were used, and these were used in a weight ratio of Compound No. I-1: Cyanine dye D-2: Phthalocyanine dye A-3: An optical recording disk sample No. 13 was prepared in the same manner except that a dye mixed in a ratio of 2: 1: 2 was used. The characteristics were evaluated as in Example 8.
The same good results as those described above were obtained.

The above cyanine dye B-2 had a λmax of 610 nm when a thin film sample having a thickness of 80 nm was used.
And n and k at 650 nm obtained by the above method were n = 2.5 and k = 0.08.

Example 14 In Example 8, as a dye for the optical recording layer, a metal-containing azo compound No. I-29, cyanine dye B-5, and phthalocyanine dyes A-3 and A-28 were used in a weight ratio of compound No. I-29: Cyanine dye B-5:
Phthalocyanine dye A-3: Phthalocyanine dye A
An optical recording disk sample N was prepared in the same manner except that dyes mixed at -28 = 2: 1: 1: 1 were used and a 2.25 wt% solution of these mixed dyes in 2-ethoxyethanol was used.
When o.14 was manufactured and the characteristics were evaluated in the same manner, the same good results as in Example 8 were obtained.

Compound No. I-29 had a λmax of 615 nm at a film thickness of 50 nm, which was 650 nm determined by the above method.
N and k in n were 2.05 and k = 0.040. Further, the dye A-28 was used in a thin film sample having a film thickness of 80 nm, λ max = 725 nm, half width 130 nm, n =
2.4 and k = 0.09.

Example 15 An optical recording disk was prepared in the same manner as in Example 8 except that a laminated type recording layer was used instead of the mixed type.

On the substrate, the metal-containing azo compound No. I-1
And a cyanine dye B-5 were mixed at a weight ratio of 1: 1 to apply a 0.6 wt% solution of 2-ethoxyethanol by spin coating, followed by drying at 60 ° C. for 3 hours to obtain 500A.
The lower layer of the recording layer having a thickness of 1 is provided.

A 2.0 wt% solution of phthalocyanine dye A-44 in ethylcyclohexane was applied onto the lower layer of the recording layer by spin coating, and dried at 60 ° C. for 3 hours to form an upper layer of the recording layer having a thickness of 1000 A. Layered.

An Au reflective layer having a thickness of 850 A is formed on the recording layer having such a two-layer structure by a sputtering method, and an ultraviolet curable acrylic resin having a thickness of 5 μm is used as a protective film.
Formed to a thickness of.

The phthalocyanine dye A-44 was measured in a thin film sample having a film thickness of 80 nm with λ max = 728 nm,
The half-width was 140 nm, n = 2.2, and k = 0.09.

In this way, the disc sample No. Fifteen
Was produced.

This disk sample No. On the other hand, a laser (oscillation wavelength of 780 nm) is used for 15 and linear velocity of 1.2 m /
Recording was performed for 2 seconds, and reproduction was performed with a laser (oscillation wavelength: 780 nm) and a laser (oscillation wavelength: 650 nm), and the optimum recording power (PO), modulation (I11Mod) and reflectance (Rtop) were measured.

Also, a xenon lamp (Xenon fade meter manufactured by Shimadzu Corporation) of 80,000 lux was irradiated for 200 hours, and the modulation (I11Mod) and reflectance (Rtop)
Was measured after irradiation.

The results are shown below.

Disk sample No. 15 is CD-RII
As a result, it was found that they have sufficiently good characteristics and have excellent light stability. It was also found that the photodegradation of the cyanine dye is improved by using the metal-containing azo compound of the present invention.

Comparative Example 1 As the dye for the optical recording layer, the following azo dye whose counter cation was Na ⁺ was used, and as the solvent, 3 kinds of 2-ethoxyethanol, tetrafluoropropanol and ethylcyclohexane were used, and 2 wt. %, 3 types of disks were tried in exactly the same manner as in Example 1 except that it was applied as a solution.

As a result, no matter which solvent was used, evaluation was not possible because crystals were formed on the surface of the dye film due to insufficient solubility of the dye.

[0204]

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Comparative Example 2 According to the example of JP-A-2-55189, the compound No. 1 of the present invention was used as an optical recording dye. I-1 and the following pentamethine cyanine dye were used, and compound No. 1 was used in a weight ratio. I-
A disk was formed in the same manner as in Example 7 except that 1: 1: cyanine dye = 1: 1.

[0206]

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A laser (oscillation wavelength of 780 n
m) is used for recording at a linear velocity of 1.2 m / sec, and reproduction is performed with a laser (oscillation wavelength of 780 nm) to obtain optimum recording power (PO), modulation (I11Mod), and reflectance (R).
top) was measured.

In addition, a xenon lamp (Xenon fade meter manufactured by Shimadzu) of 80,000 lux was irradiated for 25 hours,
The changes in the modulation (I11Mod) and reflectance (Rtop) after irradiation were measured.

The results are shown below. Initial value After irradiation Rtop 60% 40% I11Mod 66% 25% (large deterioration of jitter occurs) PO 7.2mW

It was found that when the compound of the present invention was used in the method described in the above publication, the characteristics were deteriorated in recording / reproducing at 780 nm.

Comparative Example 3 As a dye for the optical recording layer, a trimethine cyanine dye B-
5 and phthalocyanine dye A-3 are used, and in a weight ratio, cyanine dye B-5: phthalocyanine dye A-3 =
A disk was formed in the same manner as in Example 8 except that the dye mixed at 1: 1 was used, and a laser (oscillation wavelength 7
Recording at a linear velocity of 1.2 m / sec using a laser (oscillation wavelength of 780 nm) and a laser (oscillation wavelength of 65 nm).
The reproduction was performed at 0 nm), and the optimum recording power (PO), modulation (I11Mod), and reflectance (Rtop) were measured.

Further, a xenon lamp (Xenon fade meter manufactured by Shimadzu Corporation) of 80,000 lux was irradiated for 20 hours,
The changes in the modulation (I11Mod) and reflectance (Rtop) after irradiation were measured.

The results are shown below.

As described above, it is understood that the photo-deterioration of the cyanine dye is remarkable unless the metal-containing azo compound of the present invention is used.

Comparative Example 4 Optical recording was carried out in the same manner as in Example 1 except that the following chromium-containing azo compound described in JP-B-7-37580 was used as the dye for the optical recording layer and cyclohexane was used as the coating solvent. When a disk was produced and an attempt was made to evaluate the characteristics in the same manner as in Example 1, recording could not be performed and the characteristics could not be evaluated.

[0216]

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Comparative Example 5 Japanese Examined Patent Publication No. 7-42451 (corresponding to JP-A-63-35587)
Optical recording in the same manner as in Example 1 except that the following chromium complex compound described in Japanese Patent Publication No. JP-A-2003-242200 is used as a dye for an optical recording layer, acetone is used as a coating solvent, and a substrate material is polymethylmethacrylate (PMMA) resin. When a disk was prepared and the evaluation of characteristics was tried in the same manner as in Example 1,
No recording could be done and the properties could not be evaluated.

[0218]

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Comparative Example 6 In Example 5, the compound No. An optical recording disk was prepared in the same manner except that the following bisphenyldithiol-based Ni complex quencher was used instead of I-1, and the characteristics were evaluated in the same manner. Both the reflectance and the modulation of have decreased.

[0220]

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[0221]

[0222]

According to the present invention, an optical recording medium having excellent characteristics such as high recording sensitivity and small jitter can be obtained by using a metal-containing azo compound having excellent solubility and light resistance as a light absorbing dye. . Further, when a trimethine cyanine dye having no light resistance and having an absorption at a wavelength similar to that of the metal-containing azo compound of the present invention is used as a light absorbing dye, the metal-containing azo compound of the present invention should be mixed. Thus, an excellent optical recording medium having improved light resistance can be obtained.

When mixed with a dye having absorption on the long wavelength side, a dual wavelength type optical recording medium can be formed.

[Brief description of drawings]

FIG. 1 is a graph illustrating a method of obtaining a half width of an absorption spectrum of a thin film of a phthalocyanine dye.

FIG. 2 is a partial sectional view showing an example of the optical disc of the present invention.

FIG. 3 is a partial cross-sectional view showing another example of the optical disc of the present invention.

[Explanation of symbols]

 1, 10 Optical recording disk 2, 12, 22 Substrate 23, 123, 223 Groove 3, 13, 23 Recording layer 4, 14, 24 Reflective layer 5, 15, 25 Protective film 50 Adhesive layer

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G11B 7/24 516 8721-5D G11B 7/24 516 (72) Inventor Atsushi Kadota 1-13, Nihonbashi, Chuo-ku, Tokyo No. 1 TDK Corporation

Claims (10)

[Claims] 1. A recording layer containing a dye is provided on a substrate,
An optical recording medium having a reflective layer on the recording layer and a protective film on the reflective layer, wherein the recording layer contains a metal-containing azo compound represented by the following formula (I). . Embedded image [In the formula (I), R ¹ and R ² are each a nitro group,
It represents a halogen atom, an amino group, a sulfamoyl group, an alkyl group or an alkoxy group, and t and u are each 0 or an integer of 1 to 4. R ³ and R ⁴ represent a halogen atom, a nitro group, an alkyl group, an alkoxy group or an amino group, and v and w are 0 or an integer of 1 to 6, respectively. M ¹ represents cobalt or nickel. Y ⁺ represents an alkyl-substituted ammonium ion. However, t, u,
v and w never become 0 at the same time, and t + u + v +
w is 1 to 20. ] 2. The optical recording medium according to claim 1, wherein the recording layer contains a trimethine cyanine dye represented by the following formula (II). Embedded image [In the formula (II), Q ₁ and Q ₂ represent a group of atoms necessary for completing a heterocycle with a carbon atom and a nitrogen atom, respectively, and the heterocyclic skeleton completed by Q ₁ or Q ₂ may be the same. It may be different. R ₁ and R ₂ each represent an aliphatic hydrocarbon group, which may be the same or different. R ₃ represents a hydrogen atom or a monovalent substituent. X ⁻ represents a monovalent anion. ] 3. The recording layer contains a second light absorbing dye having optical characteristics different from those of the metal-containing azo compound or the trimethinecyanine dye, the first wavelength light of 630 to 690 nm and 770 to 790 nm. The optical recording medium according to claim 1, wherein recording and reproduction are performed with a second wavelength light of 830 nm. 4. The optical recording medium according to claim 3, wherein recording is performed with the second wavelength light, and reproduction is performed with the first and second wavelength lights. 5. The real part n of the complex refractive index of the metal-containing azo compound and the trimethine cyanine dye at 650 nm is 1.8 to 2.6, and the imaginary part k is 0.02 to 0.20.
And the real part n of the complex refractive index at 780 nm of the second light absorbing dye is 1.8 to 2.6, and the imaginary part k is 0.02 to 0.
30 and the full width at half maximum of the absorption spectrum of the thin film is 170
The optical recording medium according to claim 3, wherein the recording layer having a thickness of nm or less is provided on a substrate. 6. A first recording layer containing the metal-containing azo compound or the compound and the trimethine cyanine dye in the first recording layer containing a second light absorbing dye having optical characteristics different from those of the compound. The optical recording medium according to claim 1 or 2, wherein two recording layers are laminated to form two or more recording layers. 7. The real part n of the complex refractive index at 650 nm of the metal-containing azo compound or the trimethine cyanine dye is 1.8 to 2.6, and the imaginary part k is 0.02 to 0.20. And the real part n of the complex refractive index of the second light absorbing dye at 780 nm is 1.8 to 2.6, and the imaginary part k is 0.02 to 0.1.
5, the half-width of the absorption spectrum of the thin film is 170 nm
The optical recording medium according to claim 6, which is the following and has the two or more recording layers provided on a substrate. 8. A first recording layer is provided on a substrate.
8. The optical recording medium according to claim 6, wherein a second recording layer is provided on said recording layer. 9. The optical recording medium according to claim 3, wherein the second light absorbing dye is a phthalocyanine dye represented by the following formula (III). Embedded image [In Formula (III), M represents a central atom. X ₁ , X
₂ , X ₃ and X ₄ each represent a halogen, which may be the same or different. p1, p2, p3
And p4 are each 0 or an integer of 1 to 4, and p1 +
p2 + p3 + p4 is 0-15. Y ₁ , Y ₂ , Y ₃
And Y ₄ each represent an oxygen atom or a sulfur atom, which may be the same or different. Z ₁ , Z
₂ , Z ₃ and Z ₄ each represent an alkyl group having 4 or more carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group, which may be the same or different. q1, q2, q3 and q4 are each 0 or 1-4.
Which are not simultaneously 0, and q
1 + q2 + q3 + q4 is 1 to 8. ] 10. The film thickness of each of the first recording layer and the second recording layer is 20 to 250 nm, and the film thickness of the first recording layer is divided by the film thickness of the second recording layer. When the value is 0.
10. The optical recording medium according to claim 8, wherein the optical recording medium is 1 to 1.