JP2000052658A - Information recording medium, and new oxonol compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high recording property, and also, provide a high stability extending to a long period of time, and perform the recording and reproduction of information by a visible laser beam by using a coloring matter compound which is represented by a specified formula, for a recording layer. SOLUTION: On the surface of a substrate (or an undercoating layer) where a pre-groove is formed, a recording layer containing a coloring matter compound which is represented by the formula (R1, R2, R3, and R4 each independently represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, L1, L2, and L3 each independently represent a methine group which may have a substituted group, (m) is 0, 1, 2 or 3, Xk+ represents a cation, (k) is an integer of 1-10), is provided, and on the recording layer, the recording of information is possible by a laser beam. By this method, a high reflectance and a low jitter are achieved, and a DVD-R type information recording medium which is excellent in recording properties can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat mode type information recording medium and an information recording method capable of writing (recording) and reading (reproducing) information by using a laser beam having a high energy density. In particular, the present invention relates to a heat mode type information recording medium such as a write-once digital video disk (DVD-R) suitable for recording information using visible laser light.

[0002]

2. Description of the Related Art An information recording medium (optical disk) on which information can be recorded only once by a laser beam has been known. The information recording medium is a write-once CD (a so-called CD-
R), a smaller amount of CD compared to the conventional CD production
Is affordable and can be quickly provided, and the demand for personal computers has been increasing with the recent spread of personal computers. A typical structure of a CD-R type information recording medium is one in which a recording layer made of an organic dye, a reflective layer made of a metal such as gold, and a protective layer made of a resin are further laminated in this order on a transparent disk-shaped substrate. It is. Recording of information on the optical disk is performed using laser light in the near infrared region (normally 780 nm).
This is performed by irradiating a laser beam having a nearby wavelength) to locally generate and deform the recording layer. On the other hand, reading (reproducing) information is usually performed by irradiating a laser beam having the same wavelength as the recording laser beam to reflect a portion where the recording layer is heated and deformed (recorded portion) and a portion where the recording layer is not deformed (unrecorded portion). It does this by detecting differences in rates.

In recent years, an information recording medium having a higher recording density has been demanded. To increase the recording density, it is effective to reduce the diameter of the laser beam to be irradiated, and it is theoretically known that laser light having a shorter wavelength can be reduced to a smaller diameter, which is advantageous for increasing the density. Have been. Therefore,
An optical disk for performing recording and reproduction using a laser beam having a wavelength shorter than 780 nm, which is conventionally used, is being developed. For example, it is called a write-once digital video disk (so-called DVD-R). Optical disks have been proposed. This optical disc has a track pitch of CD-
A recording layer made of a dye is formed on a transparent disc-shaped substrate having a diameter of 120 mm or 80 mm on which a 0.8 μm pregroove smaller than 1.6 μm in R is formed. It is manufactured to have a structure in which two disks provided with a protective layer or a disk-shaped protective substrate having substantially the same size as the disk are bonded with an adhesive with the recording layer inside. And DVD-R
It is said that recording and reproduction are performed by irradiating visible laser light (laser light having a wavelength in the range of 600 nm to 700 nm), and recording at a higher density than that of a CD-R type optical disk is possible.

A DVD-R type information recording medium is a conventional C-type information recording medium.
Since it can record several times the amount of information as compared with the DR type, it has high recording sensitivity, and in particular, needs to process a large amount of information promptly. It is also desirable that the error rate be low. In addition, since a recording layer made of a dye generally has low stability over time with respect to heat or light, it is desired to develop a recording layer capable of maintaining stable performance with respect to heat or light over a long period of time.

Japanese Patent Application Laid-Open No. 63-209959 discloses a C-type recording medium having a recording layer comprising an oxonol dye provided on a substrate.
A DR type information recording medium is disclosed. It is described that by using this dye compound, stable recording / reproducing characteristics can be maintained for a long period of time. And here,
An oxonol dye compound in which ammonium is introduced in the form of a salt in the molecule is described.

[0006]

The inventor of the present invention used the oxonol dye described in the above-mentioned publication for a DVD-R type information recording medium and examined the performance thereof. As a result, a DVD-R containing the oxonol dye in the recording layer
Although the type-type information recording medium shows relatively high recording characteristics, it has been found that the reflectivity and the degree of modulation are low and the recording / reproducing characteristics are not sufficiently satisfactory. It has also been found that when exposed to light such as sunlight for a long time, defective reproduction is likely to occur, and therefore, the light resistance is also insufficient. Therefore, the main object of the present invention is to provide high recording characteristics and high stability so that the recording characteristics can be sufficiently maintained over a long period of time (particularly, high stability in light resistance).
It is an object of the present invention to provide an information recording medium capable of suitably performing recording and reproduction of information with a visible laser beam, and a method for recording information using the information recording medium.

[0007]

According to the present inventors, by using the dye compound represented by the general formula (I-1) in the recording layer, the recording / reproducing characteristics are superior to those of the prior art, and the light resistance and the light resistance are improved. An information recording medium having further improved storage durability and high storage stability was found. The problem has been solved by the following (1) to (5).

(1) In an information recording medium in which a recording layer on which information can be recorded by a laser beam is provided on a substrate, the recording layer is a dye compound represented by the following general formula (I-1): An information recording medium comprising:

[0009]

Embedded image

Wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a heterocyclic group, and L ₁ , L ₂ and L ₃ Each independently represents a methine group which may have a substituent;
Represents 0, 1, 2, or 3, X ^{k +} represents a cation,
k represents an integer of 1 to 10. (2) The information recording medium according to (1), wherein X ^{k +} is a quaternary ammonium ion. (3) The information recording medium according to (1), wherein X ^{k +} is an onium ion represented by the following general formula (I-2).

[0011]

Embedded image

[Wherein, R ₅ and R ₆ each independently represent a substituent, and R ₇ and R ₈ each independently represent an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group or a heterocyclic group. R ₅ and R ₆ , R ₅ and R ₇ , R ₆
And R ₈ or R ₇ and R ₈ may be linked to each other to form a ring, r and s each independently represent an integer of 0 to 4, and when r and s are 2 or more, , A plurality of R ₅ and R ₆ may be the same or different from each other. (4) An oxonol compound represented by the following general formula (II-1).

[0013]

Embedded image

[Wherein R ₉ , R ₁₀ , R ₁₁ and R ₁₂ each independently represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a heterocyclic group, and L ₁ , L ₂ and L ₃ Each independently represents a methine group which may have a substituent;
Represents 0, 1, 2, or 3, X ^{k +} represents a cation,
k represents an integer of 1 to 10. However, when m is 1 or 2, R ₉ , R ₁₀ , R ₁₁ , and R ₁₂ are not all methyl groups, and when m is 2, R ₉ , R ₁₀ , R ₁₁ , and R 12 ₁₂ is not a combination of a methyl group and an n-hexyl group. (5) An oxonol compound represented by the following general formula (I-3).

[0015]

Embedded image

[Wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a heterocyclic group, and L ₁ , L ₂ and L ₃ Each independently represents a methine group which may have a substituent;
Represents 0, 1, 2, or 3, R ₁₃ and R ₁₄ are the same as group each represented by R ₅ and R ₆ in the formula independently (I-2), R ₁₅ and R ₁₆ Are each independently a group having 1 to 1 carbon atoms
An alkyl group having 8 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an alkynyl group having 2 to 18 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a 4- to 7-membered heterocyclic group R ₁₃ and R ₁₄ , R ₁₃ and R ₁₅ , R ₁₄ and R ₁₆
Or R ₁₅ and R ₁₆ may be linked to each other to form a 4- to 7-membered ring, r and s each independently represent an integer of 0 to 4, and when r and s are 2 or more, Is that a plurality of R ₁₃ and R ₁₄ may be the same or different from each other,
k represents an integer of 1 to 10. ]

The present invention provides a track pitch of 0.6 to 0.9.
μm pre-groove formed, diameter 120 ± 3mm
Alternatively, a dye compound represented by the following general formula (I-1) is provided on the surface of the transparent disc-shaped substrate having a diameter of 80 ± 3 mm and a thickness of 0.6 ± 0.1 mm on which the pregroove is provided. Or a pre-groove having a track pitch of 0.6 to 0.9 μm, having a diameter of 120 ± 3 mm or a diameter of 80 ± 3 mm.
The surface of the transparent disc-shaped substrate having a thickness of 0.6 ± 0.1 mm on the side where the pre-groove is provided has the following general formula (I-
A laminated body provided with a recording layer containing the dye compound represented by 1) and a disk-shaped protective plate are joined so that each recording layer is on the inside, and the thickness is 1.2 ±. A heat mode type information recording medium of 0.2 mm is preferable.

[0018]

Embedded image

[Wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a heterocyclic group, and L ₁ , L ₂ and L ₃ Each independently represents a methine group which may have a substituent;
Represents 0, 1, 2, or 3, X ^{k +} represents a cation,
k represents an integer of 1 to 10. ]

Further, the present invention relates to the above information recording medium, wherein 6
An information recording method of recording information by irradiating a laser beam having a wavelength of 00 to 700 nm is preferable.

The information recording medium of the present invention preferably has the following aspects. (1) In the general formula (I-1), X ^{k +} is a quaternary ammonium ion. (2) In the general formula (I-1), k is 1 to 4. (3) In the general formula (I-1), k is 2. (4) In the general formula (I-1), X ^{k +} is an onium ion represented by the following general formula (I-2).

[0022]

Embedded image

[Wherein R ₅ and R ₆ each independently represent a substituent, and R ₇ and R ₈ each independently represent an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group or a heterocyclic group. R ₅ and R ₆ , R ₅ and R ₇ , R ₆
And R ₈ or R ₇ and R ₈ may be linked to each other to form a ring, r and s each independently represent an integer of 0 to 4, and when r and s are 2 or more, , A plurality of R ₅ and R ₆ may be the same or different from each other. (5) A reflective layer is further provided on the recording layer. (6) In the above (5), a protective layer is further provided on the reflective layer.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The compound represented by formula (I-1) of the present invention will be described in detail. In the formula, R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group. The alkyl group is an alkyl group having 1 to 20 carbon atoms (eg, methyl, ethyl, propyl, butyl, i-butyl, t-butyl, i-amyl, cyclopropyl, cyclohexyl) and the following substituents (however, alkyl group May be excluded). Examples of the substituent (referred to as a substituent SUB) include an alkyl group having 1 to 20 carbon atoms (eg, methyl, ethyl, propyl, carboxymethyl, ethoxycarbonylmethyl) and an aralkyl group having 7 to 20 carbon atoms (eg, Benzyl, phenethyl), carbon number 1
To 8 alkoxy groups (eg, methoxy, ethoxy), aryl groups having 6 to 20 carbon atoms (eg, phenyl, naphthyl),
An aryloxy group having 6 to 20 carbon atoms (eg, phenoxy,
Naphthoxy), a heterocyclic group (eg, pyridyl, pyrimidyl, pyridazyl, benzimidazolyl, benzothiazolyl, benzoxazolyl, 2-pyrrolidinone-1-yl, 2-piperidone-1-yl, 2,4-dioxyimidazolidin-3 -Yl, 2,4-dioxyoxazolidin-3-yl, succinimide, phthalimide, maleimide), a halogen atom (eg, fluorine, chlorine, bromine, iodine), a carboxyl group, an alkoxycarbonyl group having 2 to 10 carbon atoms (eg, Methoxycarbonyl, ethoxycarbonyl), cyano group, acyl group having 2 to 10 carbon atoms (eg, acetyl, pivaloyl), carbamoyl having 1 to 10 carbon atoms (eg, carbamoyl, methylcarbamoyl, morpholinocarbamoyl), amino group, carbon group A substituted amino group of Formulas 1 to 20 (eg, dimethylamino , Diethylamino, bis (methylsulfonylethyl) amino, N-ethyl-N'-sulfoethylamino), sulfo group, hydroxyl group, nitro group, sulfonamide group having 1 to 10 carbon atoms (eg, methanesulfonamide), carbon A ureido group of Formulas 1 to 10 (eg,
Ureido, methylureide), a sulfonyl group having 1 to 10 carbon atoms (eg, methanesulfonyl, ethanesulfonyl),
It includes a sulfinyl group having 1 to 10 carbon atoms (eg, methanesulfinyl) and a sulfamoyl group having 0 to 10 carbon atoms (eg, sulfamoyl, methanesulfamoyl). The carboxyl group and the sulfo group may be in a salt state.

The aryl group represented by R ₁ , R ₂ , R ₃ and R ₄ includes an aryl group having 6 to 20 carbon atoms (eg, phenyl, naphthyl). The aryl group may have the above-mentioned substituent SUB. R ₁ , R ₂ , R ₃ and R
_The aralkyl group represented by ₄ includes an aralkyl group having 7 to 20 carbon atoms (eg, benzyl, phenethyl). The aralkyl group may have the above-mentioned substituent SUB. R
_The heterocyclic group represented by ₁ , R ₂ , R ₃ and R ₄ is a 5- or 6-membered saturated or unsaturated heterocyclic group composed of a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom. For example, pyridyl group, pyrimidyl group, pyridazyl group, piperidyl group, triazyl group, pyrrolyl group, imidazolyl group,
A triazolyl group, a furanyl group, a thiophenyl group, a thiazolyl group, an oxazolyl group, an isothiazolyl group, an isoxazolyl group, and the like, which are benzo-condensed (for example, a quinolyl group, a benzimidazolyl group, a benzothiazolyl group, a benzooxazolyl group). And the heterocyclic ring may have, for example, the above-mentioned substituent SUB.

Preferred as R ₁ , R ₂ , R ₃ and R ₄ are an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms or 6 to 10 carbon atoms. Is a heterocyclic group. R ₁ and R ₂ , or R
_{When 3} and R ₄ each represent an alkyl group, they are linked to each other to form a carbon ring (eg, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 2-methylcyclohexyl, cycloheptyl, cyclooctyl, etc.) or a heterocyclic ring (eg, piperidyl, chromanyl, Morpholyl)
And is preferably a carbon ring having 3 to 10 carbon atoms or a heterocyclic ring having 2 to 10 carbon atoms. The general formula (I
-1) (and (II-1)), those in which R ₁ and R ₂ and / or R ₃ and R ₄ are linked to form a ring structure have better wet heat storage durability.

L ₁ , L ₂ and L ₃ each independently represent a substituted or unsubstituted methine group, and examples of the substituent include the above-mentioned substituent SUB. Preferred as L ₁ , L ₂ and L ₃ are an unsubstituted methine group, an alkyl-substituted methine group having 1 to 5 carbon atoms, an aralkyl-substituted methine group having 7 to 10 carbon atoms, an aryl-substituted methine group having 6 to 10 carbon atoms, A saturated or unsaturated heterocyclic-substituted methine group and a halogen-substituted methine group. m represents 0, 1, 2 or 3. Preferably it is 1, 2 or 3. When m is 2 or more, a plurality of L ₂ and L ₃ may be the same or different.

Next, the cation portion will be described in detail. X ^{k +}
Examples of the cation represented by, for example, hydrogen ion or sodium ion, potassium ion, lithium ion,
Calcium ion, iron ion, metal ion such as copper ion, metal complex ion, ammonium ion, pyridinium ion, oxonium ion, sulfonium ion,
Examples thereof include a phosphonium ion, a selenonium ion, and an iodonium ion. X ^{k +} is preferably not a cyanine dye. Preferably, it is a quaternary ammonium ion.

The quaternary ammonium is generally a tertiary amine (eg, trimethylamine, triethylamine, tributylamine, triethanolamine, N-methylpyrrolidine, N-methylpiperidine, N, N-dimethylpiperazine, triethylenediamine, N, N ', N'
-Tetramethylethylenediamine or the like; or a nitrogen-containing heterocycle (pyridine ring, picoline ring, 2,2'-bipyridyl ring, 4,4'-bipyridyl ring, 1,10-phenanthroline ring, quinoline ring, oxazole ring, thiazole ring, N-methylimidazole ring, pyrazine ring, tetrazole ring, etc.) can be obtained by alkylation (Menstockkin reaction), alkenylation, alkynylation or arylation.

The quaternary ammonium ion represented by X ^{k +} is preferably a quaternary ammonium ion comprising a nitrogen-containing heterocyclic ring, and particularly preferably a quaternary pyridinium ion.

K represents an integer of 1 to 10. Preferably it is 1-4. Particularly preferably, it is 2.

The onium ion represented by X ^{k +} is more preferably one represented by the following general formula (I-2). These compounds are usually 2,2′-bipyridyl or 4,4 ′
Menshkin reaction of 4'-bipyridyl with a halide having a desired substituent (see, for example, JP-A-61-1481).
No. 62) or by an arylation reaction according to the methods described in JP-A-51-16675 and JP-A-1-96171.

[0033]

Embedded image

In the formula, R ₅ and R ₆ each independently represent a substituent, and R ₇ and R ₈ each independently represent an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group or a heterocyclic group. R ₅ and R ₆ , R ₅ and R ₇ , R ₆ and R _8, or R ₇ and R ₈ may be linked to each other to form a ring, and r and s each independently represent 0 to 4 Represents the integer of
When r and s are 2 or more, a plurality of R ₅ and R ₆
May be the same or different from each other.

The alkyl group represented by R ₇ and R ₈ is preferably a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms. is there. These may be linear, branched, or cyclic. Examples of these include methyl, ethyl, n-propyl, isopropyl, n
-Butyl, isobutyl, t-butyl, n-hexyl, neopentyl, cyclohexyl, adamantyl, cyclopropyl and the like.

Examples of the substituent of the alkyl group include the following. A substituted or unsubstituted alkenyl group having 2 to 18 carbon atoms (preferably 2 to 8 carbon atoms) (eg vinyl); 2 to 18 carbon atoms (preferably 2 carbon atoms)
To 8) substituted or unsubstituted alkynyl groups (eg, ethynyl); substituted or unsubstituted aryl groups having 6 to 10 carbon atoms (eg, phenyl, naphthyl); halogen atoms (eg,
F, Cl, Br and the like); a substituted or unsubstituted alkoxy group having 1 to 18 carbon atoms (preferably 1 to 8 carbon atoms) (eg,
Methoxy, ethoxy); a substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms (eg, phenoxy, p-methoxyphenoxy); substituted or unsubstituted having 1 to 18 carbon atoms (preferably 1 to 8 carbon atoms). Alkylthio group (eg,
Methylthio, ethylthio); a substituted or unsubstituted arylthio group having 6 to 10 carbon atoms (eg, phenylthio);
A substituted or unsubstituted acyl group having 2 to 18 carbon atoms (preferably 2 to 8 carbon atoms) (eg, acetyl, propionyl);

C1-18 (preferably C1-18)
8) a substituted or unsubstituted alkylsulfonyl group or arylsulfonyl group (eg, methanesulfonyl, p-
A substituted or unsubstituted acyloxy group having 2 to 18 carbon atoms (preferably 2 to 8 carbon atoms) (eg, acetoxy, propionyloxy);
18 (preferably 2 to 8 carbon atoms) substituted or unsubstituted alkoxycarbonyl group (eg, methoxycarbonyl,
Ethoxycarbonyl); a substituted or unsubstituted aryloxycarbonyl group having 7 to 11 carbon atoms (eg, naphthoxycarbonyl); an unsubstituted amino group, or 1 to 1 carbon atom
18 (preferably 1 to 8 carbon atoms) substituted amino group (eg,
Methylamino, dimethylamino, diethylamino, anilino, methoxyphenylamino, chlorophenylamino, pyridylamino, methoxycarbonylamino, n-
Butoxycarbonylamino, phenoxycarbonylamino, methylcarbamoylamino, ethylthiocarbamoylamino, phenylcarbamoylamino, acetylamino, ethylcarbonylamino, ethylthiocarbamoylamino, cyclohexylcarbonylamino, benzoylamino, chloroacetylamino, methylsulfonylamino);

C 1-18 (preferably C 1-18)
8) substituted or unsubstituted carbamoyl group (eg, unsubstituted carbamoyl, methylcarbamoyl, ethylcarbamoyl, n-butylcarbamoyl, t-butylcarbamoyl, dimethylcarbamoyl, morpholinocarbamoyl, pyrrolidinocarbamoyl); unsubstituted sulfamoyl group Or 1 to 18 carbon atoms (preferably 1 to 18 carbon atoms)
8) a substituted sulfamoyl group (eg, methylsulfamoyl, phenylsulfamoyl); a cyano group; a nitro group;
Carboxy group; hydroxyl group; heterocyclic group (eg, oxazole ring, benzoxazole ring, thiazole ring, benzothiazole ring, imidazole ring, benzimidazole ring, indolenine ring, pyridine ring, piperidine ring, pyrrolidine ring, morpholine ring, sulfolane ring , Furan ring, thiophene ring, pyrazole ring, pyrrole ring, chroman ring, coumarin ring).

The alkenyl group represented by R ₇ and R ₈ is preferably a substituted or unsubstituted alkenyl group having 2 to 18 carbon atoms, more preferably a substituted or unsubstituted alkenyl group having 2 to 8 carbon atoms. Yes, for example, vinyl,
Allyl, 1-propenyl, 1,3-butadienyl and the like can be mentioned. As the substituent for the alkenyl group, those mentioned above as the substituent for the alkyl group are preferable.

The alkynyl group represented by R ₇ and R ₈ is preferably a substituted or unsubstituted alkynyl group having 2 to 18 carbon atoms, more preferably a substituted or unsubstituted alkynyl group having 2 to 8 carbon atoms. Yes, for example, ethynyl, 2-propynyl and the like. As the substituent for the alkynyl group, those described above as the substituent for the alkyl group are preferable.

The aralkyl group represented by R ₇ and R ₈ is preferably a substituted or unsubstituted aralkyl group having 7 to 18 carbon atoms, for example, benzyl, methylbenzyl and the like. Examples of the substituent of the aralkyl group include those described above as the substituent of the alkyl group.

The aryl group represented by R ₇ and R ₈ is preferably a substituted or unsubstituted aryl group having 6 to 18 carbon atoms, such as phenyl and naphthyl. As the substituent of the aryl group, those described above as the substituent of the alkyl group are preferable. In addition to these, an alkyl group (eg, methyl, ethyl, etc.) is also preferable.

The heterocyclic group represented by R ₇ and R ₈ is
It is a 5- or 6-membered saturated or unsaturated heterocyclic ring composed of a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, and examples thereof include an oxazole ring, a benzoxazole ring, a thiazole ring, and a benzothiazole. Ring, imidazole ring, benzimidazole ring, indolenine ring,
Examples include a pyridine ring, a piperidine ring, a pyrrolidine ring, a morpholine ring, a sulfolane ring, a furan ring, a thiophene ring, a pyrazole ring, a pyrrole ring, a chroman ring, and a coumarin ring. The heterocyclic group may be substituted, and in this case, the substituent is preferably those exemplified as the substituent for the alkyl group.

R_FiveAnd R₆The substituent represented by
It has the same meaning as the substituent of the alkyl group. Also
In addition to these, alkyl groups (eg, methyl, ethyl, etc.)
Can also be mentioned. In the present invention, R_FiveAnd R
₆Is a hydrogen atom or an alkyl group.
Preferably. Particularly preferred is a hydrogen atom.
R in the general formula (I-3)₁~ R_Four, L₁~ L_Three,
The definitions of m and k are synonymous with general formula (I-1). R_FifteenPassing
And R₁₆Is R₇And R₈Corresponds to a preferred substituent of Good
The preferred substituent is also R ₇And R₈The ones listed in apply
You. L in the general formula (II-1)₁~ L_Three, M, X^{k +},
The definition of k is synonymous with general formula (I-1). General formula (II
R in -1)₉, R_Ten, R₁₁And R₁₂Is the general formula (I
R in -1)₁, R_Two, R_ThreeAnd R_FourSynonymous with
The same applies to the preferred range.

In the general formula (I-1), the cation moiety represented by the general formula (I-2) is represented by the following general formula (I-
It is particularly preferable to be represented by 4) or (I-5).

[0046]

Embedded image

Where R₁₇And R₁₈Are respectively described above
R_FiveAnd R₆Has the same meaning as the substituent represented by
The preferred ranges are the same for each. R₁₉Passing
And R ₂₀Is the above-mentioned R₇And R₈The position represented by
Synonymous with a substitution group, and for each, its preferred
Are the same. r and s are each independently 0 to 4
Represents an integer, and when r and s are 2 or more,
R₁₇And R₁₈Are the same but different
Is also good.

[0048]

Embedded image

In the formula, R ₂₁ and R ₂₂ have the same meanings as the substituents represented by R ₅ and R ₆ , respectively, and their preferred ranges are also the same. It is also preferred that R ₂₁ and R ₂₂ are connected to each other to form a carbocyclic or heterocyclic ring, and particularly preferable is a condensed aromatic ring with a pyridine ring to which R ₂₁ and R ₂₂ are respectively bonded. . r and s each independently represent an integer of 0 to 4,
When r and s are 2 or more, a plurality of R ₂₁ and R ₂₂
May be the same or different from each other.

Specific examples of the anion portion (represented by [A-]) and the cation portion (represented by "B-") of the dye compound represented by formula (I-1) used in the present invention are specifically described below. It describes in.

[0051]

Embedded image

[0052]

Embedded image

[0053]

Embedded image

[0054]

Embedded image

[0055]

Embedded image

[0056]

Embedded image

[0057]

Embedded image

[0058]

Embedded image

[0059]

Embedded image

[0060]

Embedded image

[0061]

Embedded image

[0062]

Embedded image

[0063]

Embedded image

[0064]

Embedded image

[0065]

Embedded image

[0066]

Embedded image

[0067]

Embedded image

[0068]

Embedded image

[0069]

Embedded image

[0070]

Embedded image

[0071]

Embedded image

[0072]

Embedded image

[0073]

Embedded image

[0074]

Embedded image

[0075]

Embedded image

Preferred specific examples of the compounds used in the present invention are shown in Table 1 below. In Table 1, compound examples (Dy
e) is a combination of an anion part and a cation part. For example, an example of the compound Dye No. 1 will be described below. Compound Dye No. 1 [anion moiety (A-4) /
Examples of the compound represented by the cation portion (B-21)] are represented by the following formulas, respectively.

[0077]

Embedded image

The same applies to compound examples of compound Dye No. 2 and subsequent compounds.

[0079]

[Table 1]

[0080]

[Table 2]

The 1,3-dioxane-4,6-dione skeleton of the present invention can be prepared by the method described in Chem. Ber., Vol. 94, 929-943 (1961) or Tetrah.
edron Lett., vol. 30, 5281-5284 (1989), and can be synthesized according to the method described in `` Heterocyclic Compounds-Cyanine '' by FM Hamer.・ Soy and and
Related Compounds (Heterocyclic Compounds)
-Cyaninedyes and Related Compounds (John Wiley & Sons, New York, London, 1964), pages 244 to 247.
Page, and pages 463 to 482.

The synthesis example of the oxonol compound represented by the formula (I-1) will be described below.

(Synthesis Example) (Synthesis of 1,1'-bisisobutyl-4,4'-bipyridinium dibromide) 4,4'-dipyridyl (7.8
g, 0.050 mol) and isobutyl bromide (27.4).
g, 0.20 mol) was dissolved in dimethylformamide (20 ml) and heated to 90 ° C. After stirring at 90 ° C. for 8 hours,
The yellow precipitate was filtered off and suspended in ethanol (90 ml). To this suspension was added triethylamine (2.2 ml, 0.0
16 mol) was added dropwise, and the mixture was stirred at room temperature for 1 hour. The resulting yellow precipitate was collected by filtration and washed with ethanol to give 2.1 g of 1,1'-bisisobutyl-4,4'-.
Bipyridinium dibromide was obtained. This is one of the theoretical yield
It corresponds to 0%. _{H-NMR (D 2 O)} : 9.1 (d, 4H), 8.5 (d, 4H), 4.5 (d, 4H), 2.4
(m, 2H), 1.1 (d, 12H)

(Synthesis of 1,1'-bis (2,6-diethylphenyl) -4,4'-bipyridinium dichloride)
1,1'-bis (2,4-dinitrophenyl) -4,
4'-bipyridinium dichloride (5.6 g, 0.01
0 mol) and 2,6-diethylaniline (6.6 g, 0.0
44 mol) in 70% ethanol (30 ml) and 8
After heating under reflux for an hour, the solvent was distilled off. The obtained yellow solid was suspended in water (90 ml) and stirred at room temperature for 1 hour. After filtering off the white-yellow solid, the aqueous layer was evaporated under reduced pressure, and the obtained yellow solid was washed with ethyl acetate.
4.4 g of 1,1'-bis (2,6-diethylphenyl) -4,4'-bipyridinium dichloride were obtained. This corresponds to 89% of the theoretical yield. H-NMR (D ₂ O): 9.6 (d, 4H), 9.1 (d, 4H), 7.3-7.7 (m, 6H),
2.3 (q, 8H), 1.1 (t, 12H)

(Synthesis of Dye No. 3) Meldrum's acid (2.0
g, 14.0 mmol) and N, N'-1,5-heptadien-1-yl-7-ylidenedianiline hydrochloride (2.2)
g, 7.1 mmol) was dissolved in dimethylformamide (30 ml), and triethylamine (3.0 ml, 2 ml) was added under ice-cooling.
(1.3 mmol) was added dropwise and stirred at room temperature for 3 hours. After the reaction solution was concentrated under reduced pressure, silica gel column chromatography (developing solvent: methylene chloride / methanol = 4/1)
And 0.81 g of purple powder Dye No. 3 was obtained. This corresponds to 24% of the theoretical yield. H-NMR (DMSO-d6): 8.9 (s, 1H), 7.6 (d, 2H), 7.1-7.4 (m, 4
H), 6.3 (dd, 1H), 3.1 (q, 6H), 1.5 (s, 12H), 1.2 (t, 9H) λmax: 648 nm (in methanol)

(Synthesis of Dye No. 1) Dye No. 3 (0.8 g,
(1.7 mmol) was dissolved in methanol (30 ml) and stirred at room temperature for 30 minutes. To this solution was added 1,1'-bisisobutyl-4,4'-bipyridinium dibromide (0.4%).
g, 0.9 mmol) and stirred at room temperature for 4 hours. Water (100 ml) was added to the reaction solution, and the resulting precipitate was collected by filtration, washed with water and dried to obtain 0.6 g of Dye No. 1. This corresponds to 66% of the theoretical yield. H-NMR (DMSO-d6): 9.4 (d, 2H), 8.8 (d, 2H), 7.6 (d, 2H),
7.1-7.4 (m, 4H), 6.3 (dd, 1H), 4.5 (d, 2H), 2.4 (m, 1H),
0.9 (d, 6H) λmax: 648nm (in methanol)

(Synthesis of Dye No. 10) Meldrum's acid (1
7.2 g, 0.12 mol) and N, N'-1,3-pentadien-1-yl-5-ylidenedianiline hydrochloride (1
4.2 g, 0.050 mol) was dissolved in methanol (100 ml), and triethylamine (25.0 ml,
0.18 mol) was added dropwise, and the mixture was stirred at room temperature for 3 hours. After filtering off the insoluble matter, the mother liquor was concentrated under reduced pressure, purified by silica gel column chromatography (developing solvent: methylene chloride / methanol = 10/1), and purple powder Dye No.10
13.2 g were obtained. This corresponds to 52% of the theoretical yield. H-NMR (DMSO-d6): 8.9 (s, 1H), 7.7 (d, 2H), 7.5 (dd, 1H),
7.2 (dd, 2H), 3.1 (q, 6H), 1.5 (s, 12H), 1.2 (t, 9H) λmax: 550 nm (in methanol)

(Synthesis of Dye No. 5) Dye No. 10 (0.9
g, 2.0 mmol) in methanol (30 ml),
Stirred at room temperature for 30 minutes. To this solution was added 1,1'-bis (2,6-diethylphenyl) -4,4'-bipyridinium dichloride (0.7 g, 1.4 mmol), and the mixture was stirred at room temperature for 4 hours. Water (100 ml) was added to the reaction solution,
The resulting precipitate was collected by filtration, washed with water and dried to obtain 0.8 g of Dy.
e No.5 was obtained. This corresponds to 68% of the theoretical yield. H-NMR (DMSO-d6): 9.6 (d, 2H), 9.1 (d, 2H), 7.7 (m, 3H),
7.5 (m, 3H), 7.2 (dd, 2H), 2.3 (q, 4H), 1.5 (s, 12H), 1.1
(t, 9H) λmax: 550nm (in methanol)

(Synthesis of Dye No. 50) The following compound a (3.
9 g, 0.020 mol) and N, N'-1,3-pentadien-1-yl-5-ylidenedianiline hydrochloride (2.6)
g, 9.0 mmol) was dissolved in dimethylformamide (10 ml), and triethylamine (4.0 ml, 0.1 ml) was added under ice cooling.
029 mol) was added dropwise, and the mixture was stirred at room temperature for 3 hours. After concentrating the reaction solution under reduced pressure, silica gel column chromatography (developing solvent: methylene chloride / methanol = 10/1).
To obtain 4.0 g of golden powder Dye No. 50.
This corresponds to 97% of the theoretical yield. H-NMR (DMSO-d6): 7.6 (d, 2H), 7.5 (dd, 1H), 7.2 (dd, 2H),
2.3 (m, 2H), 1.8 (m, 2H), 1.3-1.7 (m, 14H), 0.9 (d, 6H) λmax: 553 nm (in methanol)

[0090]

Embedded image

(Synthesis of Dye No.48) Dye No.50 (0.5
g, 1.0 mmol) in methanol (30 ml), and triethylamine (0.14 ml, 1.0 mmol) was added dropwise, followed by stirring at room temperature for 30 minutes. 1,1'-
Bis (2,6-diethylphenyl) -4,4'-bipyridinium dichloride (0.35 g, 0.7 mmol) was added and stirred at room temperature for 4 hours. Water (100 ml) was added to the reaction solution, and the resulting precipitate was collected by filtration, washed with water, and dried to give 0.5 ml.
7 g of Dye No. 48 was obtained. This corresponds to 85% of the theoretical yield. λmax: 553nm (in methanol)

(Synthesis of Dye No. 79) The following compound b (1.
2 g, 6.0 mmol) and N, N'-1,3-pentadien-1-yl-5-ylidenedianiline hydrochloride (0.8 g).
g, 3.0 mmol) in dimethylformamide (10 ml) and triethylamine (1.2 ml, 9.
0 mmol) was added dropwise, and the mixture was stirred at room temperature for 3 hours. After the reaction solution was concentrated under reduced pressure, purification was performed by silica gel column chromatography (developing solvent: methylene chloride / methanol = 20/1) to obtain 1.3 g of the following dye compound c as a golden powder. This corresponds to 80% of the theoretical yield. H-NMR (DMSO-d6): 8.9 (s, 1H), 7.3-7.5 (m, 13H), 6.9 (dd,
2H), 3.1 (q, 6H), 1.8 (s, 6H), 1.2 (t, 9H) λmax: 558 nm (in methanol)

[0093]

Embedded image

The dye compound c (0.6 g, 1.0 mmo)
l) in methanol (30 ml)
Stirred for minutes. To this solution was added 1,1'-bis (2,6-diethylphenyl) -4,4'-bipyridinium dichloride (0.3 g, 0.6 mmol), and the mixture was stirred at room temperature for 4 hours. Water (100 ml) was added to the reaction solution, and the resulting precipitate was collected by filtration, washed with water, and dried to obtain 0.6 g of Dye No. 79. This corresponds to 89% of the theoretical yield. H-NMR (DMSO-d6): 9.6 (d, 2H), 9.1 (d, 2H), 7.2-7.8 (m, 15
H), 6.9 (dd, 2H), 2.3 (q, 4H), 1.7 (s, 6H), 1.1 (t, 6H) λmax: 558 nm (in methanol)

The dye compound represented by formula (I-1) according to the present invention may be used alone or in combination of two or more. Alternatively, the dye compound according to the present invention may be used in combination with a dye compound conventionally known as a dye compound for an information recording medium.
Examples of these include oxonol-based dyes, cyanine-based dyes, azo metal complexes, phthalocyanine-based dyes, pyrylium-based dyes, thiopyrylium-based dyes, azurenium-based dyes, squarylium-based dyes, and naphthoquinone-based dyes other than those used in the present invention. Examples include triphenylmethane-based dyes and triallylmethane-based dyes.

The information recording medium of the present invention has the general formula (I)
The recording layer containing the dye compound represented by formula (1) has a diameter of 120 ± 3 mm or 80 ± 3 mm formed with a pre-groove having a track pitch of 0.6 to 0.9 μm, and a thickness of 0.6 ± 0. It is provided on the surface of the 1 mm transparent disc-shaped substrate on the side where the pregroove is provided. In the information recording medium of the present invention, it is preferable that a reflective layer is further provided on the recording layer, and a protective layer can be further provided on the reflective layer.

The information recording medium of the present invention preferably has the following embodiments. (1) A transparent disc-shaped substrate having a track pitch of 0.6 to 0.9 μm and a diameter of 120 ± 3 mm or a diameter of 80 ± 3 mm and a thickness of 0.6 ± 0.1 mm. On the surface on the side where the pre-groove is provided, two laminates having a recording layer containing the dye compound represented by the general formula (I-1) according to the present invention are provided. Thickness 1.2, which is joined to be inside
± 0.2mm information recording medium. (2) A transparent disk-shaped substrate having a diameter of 120 ± 3 mm or a diameter of 80 ± 3 mm and a thickness of 0.6 ± 0.1 mm on which a pregroove having a track pitch of 0.6 to 0.9 μm is formed. A laminate having a recording layer containing the dye compound represented by formula (I-1) according to the present invention provided on the surface on the side where the pregroove is provided, substantially the same as the disc-shaped substrate An information recording medium having a thickness of 1.2 ± 0.2 mm, which is formed by joining a disc-shaped protective plate having dimensions to a recording layer inside. In the above-described embodiment, it is preferable that a reflective layer is provided on the recording layer. Further, a protective layer may be further provided on the reflective layer.

The method for manufacturing the information recording medium of the present invention will be described. The information recording medium of the present invention is basically a CD-R type except that a substrate on which a pre-groove having a narrower track pitch is formed than a CD-R is used in order to achieve a higher recording density. It can be manufactured using a material used for manufacturing an information recording medium. That is, DV
For a DR information recording medium, two laminates in which a recording layer, a reflective layer, and, if desired, a protective layer are sequentially formed on a substrate are formed, and these are joined with an adhesive with the recording layer inside. Alternatively, it can be manufactured by bonding the laminated body and a disk-shaped protective substrate having substantially the same dimensions as the substrate of the laminated body with an adhesive in the same manner.

The information recording medium of the present invention can be manufactured, for example, by the following method. The substrate (including the protective substrate) can be arbitrarily selected from various materials used as a substrate of a conventional information recording medium. Examples of the substrate material include glass; polycarbonate; acrylic resins such as polymethyl methacrylate; vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymer; epoxy resins; amorphous polyolefin and polyester; May be used in combination. Note that these materials can be used in the form of a film or a rigid substrate. Among the above materials, polycarbonate is preferred from the viewpoints of moisture resistance, dimensional stability, cost, and the like.

An undercoat layer may be provided on the surface of the substrate on which the recording layer is provided, for the purpose of improving flatness, improving adhesive strength, preventing deterioration of the recording layer, and the like. Examples of the material of the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, and chlorosulfonation. Polymeric substances such as polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate, etc .; and silane coupling agents And other surface modifiers.
The undercoat layer is formed by dissolving or dispersing the above substances in an appropriate solvent to prepare a coating solution, and then applying the coating solution to the substrate surface by a coating method such as spin coating, dip coating, or extrusion coating. can do. The thickness of the undercoat layer is generally in the range of 0.005 to 20 μm, preferably in the range of 0.01 to 10 μm.

Further, on the substrate (or the undercoat layer), irregularities (pre-grooves) representing information such as tracking grooves or address signals are formed. This pre-groove is preferably formed directly on the substrate at the track pitch when a resin material such as polycarbonate is injection-molded or extruded. Alternatively, the pre-groove may be formed by providing a pre-groove layer. As a material for the pregroove layer, a mixture of at least one monomer (or oligomer) of acrylic acid monoester, diester, triester and tetraester and a photopolymerization initiator can be used.
For the formation of the pre-groove layer, for example, first, a mixed solution composed of the above-mentioned acrylate ester and the polymerization initiator was applied on a precisely formed master (stamper), and further, a substrate was placed on this coating solution layer. Thereafter, the coating layer is cured by irradiating ultraviolet rays through the substrate or the matrix to fix the substrate and the coating layer. Next, it can be obtained by peeling the substrate from the matrix. The thickness of the pregroove layer is generally in the range of 0.05 to 100 μm, preferably in the range of 0.1 to 50 μm.

The depth of the pregroove is 300 to 2000 mm.
Is preferable, and the half-value width is in the range of 0.1.
It is preferably in the range of 2 to 0.9 μm. By setting the depth of the pre-groove layer in the range of 1500 to 2000 °, sensitivity can be improved without substantially lowering the reflectance, which is particularly preferable. Therefore, such an optical disk (a deep pre-groove substrate has the general formula (I
-1) or a recording layer made of the dye of the general formula (I-2) and an optical disc having a reflective layer formed thereon) have a high sensitivity, so that recording is possible even with a low laser power, thereby making it inexpensive. It is possible to use a simple semiconductor laser or extend the service life of the semiconductor laser.

On the surface of the substrate (or the undercoat layer) where the pregroove is formed, a recording layer comprising the dye compound represented by the above formula according to the present invention is provided. The recording layer may contain various compounds conventionally known as a singlet oxygen quencher in order to further improve light resistance. As typical examples of the quencher, general formula (III) described in JP-A-3-224793,
The metal complex represented by (IV) or (V), a diimmonium salt, an aminium salt, and a nitroso compound described in JP-A-2-300287 and JP-A-2-300288 can be exemplified.

The recording layer is formed by dissolving the dye according to the present invention and, if desired, a quencher and a binder in a solvent to prepare a coating solution, and then applying the coating solution to the substrate surface to form a coating film. After forming, it can be carried out by drying. Solvents for the coating solution for forming the dye recording layer include esters such as butyl acetate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane and chloroform; Amides such as formamide; hydrocarbons such as cyclohexane; ethers such as tetrahydrofuran, ethyl ether and dioxane; alcohols such as ethanol, n-propanol, isopropanol, n-butanol and diacetone alcohol; Fluorinated solvents such as tetrafluoropropanol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and propylene glycol monomethyl ether And the like.
The above solvents can be used alone or in combination of two or more in consideration of the solubility of the compound used. Various additives such as an antioxidant, a UV absorber, a plasticizer, and a lubricant may be further added to the coating solution according to the purpose.

Examples of the binder include natural organic high-molecular substances such as gelatin, cellulose derivatives, dextran, rosin, and rubber; and hydrocarbon resins such as polyethylene, polypropylene, polystyrene, and polyisobutylene; Vinyl resins such as vinylidene chloride and polyvinyl chloride / polyvinyl acetate copolymer; acrylic resins such as polymethyl acrylate and polymethyl methacrylate; polyvinyl alcohol, chlorinated polyethylene, epoxy resin, butyral resin, rubber derivatives, and phenol -Synthetic organic polymers such as precondensates of thermosetting resins such as formaldehyde resins. When a binder is used in combination as a material for the recording layer, the amount of the binder used is generally in the range of 0.01 to 50 times (weight ratio) the dye, preferably 0.1 to 5 times. (Weight ratio). The concentration of the coating solution thus prepared is generally in the range of 0.01 to 10% by weight, preferably in the range of 0.1 to 5% by weight.

Examples of the coating method include a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method. The recording layer may be a single layer or a multilayer. The thickness of the recording layer is generally in the range from 20 to 500 nm, preferably in the range from 50 to 300 nm.

On the recording layer, a reflection layer is provided for the purpose of improving the reflectance at the time of reproducing information. The light-reflective substance that is the material of the reflection layer is a substance having a high reflectance with respect to laser light, and examples thereof include Mg, Se, Y, and T.
i, Zr, Hf, V, Nb, Ta, Cr, Mo, W, M
n, Re, Fe, Co, Ni, Ru, Rh, Pd, I
r, Pt, Cu, Ag, Au, Zn, Cd, Al, G
a, In, Si, Ge, Te, Pb, Po, Sn, Bi
Metal and semimetal or stainless steel. Of these, preferred are Cr, N
i, Pt, Cu, Ag, Au, Al and stainless steel. These substances may be used alone, or in combination of two or more kinds, or as an alloy. The reflective layer can be formed on the recording layer by, for example, vapor deposition, sputtering, or ion plating of the above-mentioned reflective substance. The thickness of the reflective layer is generally in the range of 10 to 300 nm, preferably 50 to 300 nm.
The range is 200 nm.

A protective layer may be provided on the reflective layer for the purpose of physically and chemically protecting the recording layer and the like. This protective layer may be provided on the side of the substrate where the recording layer is not provided for the purpose of enhancing the scratch resistance and the moisture resistance.
As a material used for the protective layer, for example, SiO, S
Examples include inorganic substances such as iO ₂ , MgF ₂ , SnO ₂ , and Si ₃ N _4, and organic substances such as a thermoplastic resin, a thermosetting resin, and a UV-curable resin. The protective layer can be formed, for example, by laminating a film obtained by extrusion of a plastic on the reflective layer and / or the substrate via the adhesive layer. Alternatively, it may be provided by a method such as vacuum deposition, sputtering, or coating. In the case of a thermoplastic resin or a thermosetting resin, it can also be formed by dissolving in an appropriate solvent to prepare a coating solution, applying the coating solution, and drying. In the case of a UV-curable resin, it can also be formed by preparing a coating solution as it is or by dissolving it in an appropriate solvent, applying the coating solution, and irradiating with UV light to cure. Various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added to these coating solutions according to the purpose. The layer thickness of the protective layer is generally 0.
It is in the range of 1 to 100 μm. Through the above steps, a laminate in which a recording layer, a reflective layer, and, if desired, a protective layer are provided on a substrate can be manufactured. By preparing two laminates as described above and bonding them together with an adhesive so that each recording layer is on the inside, a DVD-R type information recording medium having two recording layers is obtained. Can be manufactured. Examples of the laminating method include a method using a slow-acting ultraviolet-curable adhesive, a hot-melt method, and a method of laminating with an adhesive tape. A method using a curable adhesive is preferred. As the adhesive, it is preferable to use a non-solvent type adhesive. The application of the adhesive can be performed by a spray method, a spin coating method, a roll coating method, a screen printing method, or the like. Among them, the screen printing method is preferable. A DVD having a recording layer only on one side by bonding the obtained laminate and a disc-shaped protective substrate having substantially the same dimensions as the substrate of the laminate with an adhesive such that the recording layer is on the inside. -An R-type information recording medium can be manufactured.

The information recording method of the present invention is performed using the above information recording medium, for example, as follows. First, the information recording medium is set at a constant linear velocity (1.2 for the CD format).
１４14 m / sec) or a laser beam for recording such as a semiconductor laser beam is irradiated from the substrate side while rotating at a constant angular velocity. By this light irradiation, a cavity is formed at the interface between the recording layer and the reflective layer (the cavity is formed by deforming the recording layer or the reflective layer, or by deforming both layers),
It is considered that information is recorded when the substrate is overlaid and deformed, or when the refractive index changes due to discoloration of the recording layer or a change in the association state. The recording light is a laser light in the visible region, usually 600 nm to 700 nm (preferably 620 nm).
680 nm, more preferably 630-650 nm)
A semiconductor laser beam having an oscillation wavelength in the range described above is used. Reproduction of information recorded as described above is performed by irradiating a semiconductor laser beam having the same wavelength as at the time of recording from the substrate side while rotating the information recording medium at the same constant linear speed as above, and detecting the reflected light. Can be performed.

[0110]

(Preparation of optical recording medium)

(Example 1) Using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd.), a polycarbonate resin was spirally grooved (depth: 156 nm, width: 290 nm, track pitch: 0.1 mm).
It was formed into a substrate having a thickness of 0.6 mm and a diameter of 120 mm having a thickness of 74 μm). Pigment No. 5 2.0 g was added to 2,2,3,3-
A coating solution dissolved in 100 ml of tetrafluoropropanol was prepared, and this coating solution was applied on the surface of the substrate on which the grooves were formed by spin coating to form a dye layer. At this time, the thickness of the dye layer was 150 nm. Next, after a reflective layer having a thickness of about 150 nm is formed by sputtering silver on the dye-coated surface, an ultraviolet-curable resin (Die Cure Clear SD-318 manufactured by Dainippon Ink and Chemicals, Inc.) is formed on the reflective layer.
Is applied by a spin coating method and irradiated with ultraviolet rays from a metal halide lamp to form a protective layer of about 7 μm.
A disk A having a thickness of mm was obtained. In addition, silver was sputtered on the substrate without applying a dye to form a protective layer, and a 0.6 mm thick disc B having no dye recording layer was obtained. The following steps were performed in order to bond the disc A and the disc B together to complete one disc. First, a slow-acting cationic polymerization type adhesive (SK7000, manufactured by Sony Chemical Co., Ltd.) was applied on the protective layers of the disks A and B by screen printing. At this time, the mesh size of the screen printing plate was 300 mesh. Next, immediately after irradiation with ultraviolet rays using a metal halide lamp, disks A and B were bonded together on the protective layer side and compressed from both sides. After standing for about 5 minutes, the adhesive was completely cured and had a thickness of 1.
It was completed as one 2 mm disc.

(Examples 2) to (Example 8) Except for using the same amount of the dye according to the present invention shown in Table 2 in place of Dye No. 5 in Example 1, the procedure was the same as in Example 1. I got a disc.

Comparative Example 1 Comparative Dye A 1.0 in Table 2
g to 2,2,3,3-tetrafluoropropanol 10
A disc was completed in exactly the same manner as in Example except that the disc was dissolved in 0 ml. At this time, the thickness of the dye layer was 100 nm.

Comparative Example 2 Comparative Dye 4.0 in Table 2
g to 2,2,3,3-tetrafluoropropanol 10
A disc was completed in exactly the same manner as in Example except that the disc was dissolved in 0 ml. At this time, the thickness of the dye layer was 300 nm.

(Comparative Examples 3 to 5) Discs were obtained in exactly the same manner as in Example 1 except that Comparative Dyes J to L in Table 2 were used.

[0115]

Embedded image

[Evaluation as Optical Disc] The DVD-R type optical discs of the above-mentioned embodiment and comparative example were used for the DDU100.
Using a 0 (manufactured by Balstec) evaluator, the wavelength of the laser beam was 635 nm (pickup at NA 0.6), and the constant linear velocity was 3.
A 49 m / s, 8-16 modulated signal was recorded at a recording power of 9 mW. Thereafter, a signal was reproduced with a laser power of 0.5 mW using a laser having the same wavelength as the recording laser light, and 3T jitter and reflectance were measured. The reflectivity was measured by measuring the intensity of the return light when tracking the groove.
The pit signal length variation was measured using a time interval analyzer, and the standard deviation σ was expressed as jitter.

[0117]

[Table 3]

From the results in Table 2 above, it can be seen that the DVD according to the present invention
In the case of the -R type optical disk (Examples 1 to 8), it shows high reflectivity and low jitter, and thus it can be seen that excellent recording / reproducing characteristics are obtained. On the other hand, in the case of the DVD-R type discs for comparison (Comparative Examples 1 to 5), sufficient performance is not given particularly in jitter, and thus reading errors of digital signals are likely to occur.
Satisfactory recording and reproduction characteristics cannot be obtained. In addition, even when the reflectance is low as in Comparative Examples 1, 4, and 5, the signal intensity becomes small when reading a signal, so that a reading error of a digital signal easily occurs, and satisfactory recording / reproducing characteristics cannot be obtained. .

[0119]

As described above, by using the specific dye compound represented by the above formula into which a Meldrum's acid derivative is introduced, a high reflectivity and a low jitter are achieved, and a DVD-R type information recording medium having excellent recording characteristics can be obtained. Obtainable. Particularly, by using the dye compound according to the present invention, a lower jitter can be realized as compared with the related art.
-An information recording medium suitable for the R type can be manufactured.

Claims (5)

[Claims] 1. An information recording medium comprising a substrate and a recording layer on which information can be recorded by a laser beam, wherein the recording layer comprises a dye compound represented by the following general formula (I-1). An information recording medium characterized by including. Embedded image [Wherein, R ₁ , R ₂ , R ₃ , and R ₄ each independently represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and L ₁ , L ₂ , and L ₃ each independently represent Represents a methine group which may have a substituent, m is 0, 1,
Represents 2 or 3; X ^{k +} represents a cation;
Represents an integer of 10. ] 2. The information recording medium according to claim 1, wherein X ^{k +} is a quaternary ammonium ion. 3. The information recording medium according to claim 1, wherein X ^{k +} is an onium ion represented by the following general formula (I-2). Embedded image [Wherein, R ₅ and R ₆ each independently represent a substituent;
₇ and R ₈ are each independently an alkyl group, an alkenyl group,
Represents an alkynyl group, an aralkyl group, an aryl group or a heterocyclic group, wherein R ₅ and R ₆ , R ₅ and R ₇ , R ₆ and R ₈ or R
₇ and R ₈ may be linked to each other to form a ring;
And s each independently represent an integer of 0 to 4, and when r and s are 2 or more, a plurality of R ₅ and R ₆ may be the same or different from each other. ] 4. An oxonol compound represented by the following general formula (II-1). Embedded image [Wherein, R ₉ , R ₁₀ , R ₁₁ , and R ₁₂ each independently represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and L ₁ , L ₂ , and L ₃ each independently represent Represents a methine group which may have a substituent, m is 0, 1,
Represents 2 or 3; X ^{k +} represents a cation;
Represents an integer of 10. However, when m is 1 or 2, R ₉ ,
R ₁₀ , R ₁₁ , and R ₁₂ are not all methyl groups, and when m is 2, R ₉ , R ₁₀ , R ₁₁ , and R ₁₂ are a combination of a methyl group and an n-hexyl group Never. ] 5. An oxonol compound represented by the following general formula (I-3). Embedded image [Wherein, R ₁ , R ₂ , R ₃ , and R ₄ each independently represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and L ₁ , L ₂ , and L ₃ each independently represent Represents a methine group which may have a substituent, m is 0, 1,
Represents 2 or 3, and R ₁₃ and R ₁₄ each independently have the same meaning as the groups represented by R ₅ and R ₆ in the formula (I-2);
R ₁₅ and R ₁₆ each independently represent an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms,
An alkynyl group, an aralkyl group having 7 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms or a 4- to 7-membered heterocyclic group, wherein R ₁₃ and R ₁₄ , R ₁₃ and R ₁₅ , R ₁₄ and R ₁₆ or R ₁₅ and R ₁₆ may be linked to each other to form a 4- to 7-membered ring, r and s each independently represent an integer of 0 to 4, and when r and s are 2 or more, Has a plurality of R ₁₃ and R _{14 which} may be the same or different from each other, and k is 1 to
Represents an integer of 10. ]