JP2000343821A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide recording layers with neutrality, good stability and low cost by applying a coating fluid containing a metal complex coloring matter and using a specified non-halogen alcohol as a solvent. SOLUTION: Recording layers 13 and 23 on bases 12 and 22 of an optical recording disk 10 are formed by using a coloring matter containing a coating fluid in the spin coating process. The recording layers containing metal complex coloring matters are formed by applying a coating fluid using a non-halogen alcohol of -10 deg.C or lower melting point and 80-180 deg.C boiling point thereon for coating. As the metal complex coloring matter of sufficient melting properties and the solvent, a metal complex coloring master in which two different kinds of multidentate ligands are coordinated, particularly an azo metal complex coloring is used. Thus a disk of superior characteristics and good storage properties can be formed by using the coating solvent for melting a laser absorption coloring matter in high density, having the long life of its solvent, not damaging the base, provided with good film forming properties, inexpensive and not affecting adversely to the environment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical recording medium that forms pits by irradiating a laser.

[0002]

2. Description of the Related Art Generally, when a laser-absorbing dye is used as a recording material for an optical disc, a thin film of a recording layer is formed by a spin coating method using an organic solvent as a solvent in terms of ease of handling and cost. Have been done. Therefore, the laser absorbing dye must be dissolved in a coating solvent in addition to the light absorption / decomposition characteristics basically required for use in an optical recording medium or high light resistance for preventing photobleaching.

[0003] Generally, cyanine dyes, azo metal complex dyes, and the like are used as laser absorption dyes. Cyanine dyes are easily dissolved in organic solvents, but are very weak to light and are easily discolored. Therefore, they cannot be used alone and are usually used together with some anti-fading agent, but at that time, the solubility in an organic solvent is reduced.

[0004] On the other hand, azo metal complexes are excellent in light resistance and are suitable for optical recording media, but there are few practically usable ones because of their low solubility in solvents.

[0005] Regarding the coating solvent, the recording surface of an optical disk substrate using polycarbonate as a material is:
Grooves have been engraved in advance, and it is necessary not to damage the grooves.

However, there are few solvents that have high solubility in the dye and do not attack the substrate. Until now, fluorinated alcohol solvents (Japanese Patent Publication No.
-96333) has been used as a solvent. However, the price is very high, and water-soluble alcohols such as 2,2,3,3-tetrafluoropropanol are weakly acidic solvents. Decomposition sometimes progressed. Further, since the solvent is a halogen-based solvent, the burden on the environment such as destruction of the ozone layer is great.

JP-A-2-3373 discloses an optical information recording medium in which a recording thin film is formed by using an alcohol-based solvent as a coating solvent, but the dyes shown in Examples and Comparative Examples are as follows. It is only a cyanine dye, and is not intended for an azo metal complex dye having lower solubility than the cyanine dye.

Further, Japanese Patent Application Laid-Open No. 10-181201 discloses ethyl alcohol as a coating solvent for an azo metal complex,
Although alcohol solvents such as propyl alcohol and butyl alcohol are shown, only 2,2,3,3-tetrafluoro-1-propanol is actually used in the examples.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to increase the solubility of a dye, and so far it has been difficult to use because of its low solubility. An object of the present invention is to provide an optical recording medium using an alcohol-based solvent as a coating solvent, which has an excellent feature of low influence.

[0010]

This object is achieved by the following (1) to (6). (1) In an optical recording medium having a recording layer containing a dye on a substrate and forming pits by irradiating light to perform recording, the recording layer is formed by two different polydentate ligands. An optical recording medium comprising a coordinated metal complex dye, and formed by applying a coating solution using a non-halogen alcohol having a melting point of -10 ° C or lower and a boiling point of 80 to 180 ° C as a solvent. (2) The optical recording medium according to the above (1), wherein the non-halogen alcohol is an aliphatic saturated alcohol having a total of 3 to 6 carbon atoms. (3) The optical recording medium according to (1) or (2), wherein the recording layer contains a metal complex dye represented by the following formula (1).

[0011]

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[In the formula (1), M represents a metal atom;
A ₁ , A ₂ , B ₁ and B ₂ each independently represent an aromatic ring group having a substituent capable of coordinating to a metal, or a nitrogen-containing heteroaromatic group having a nitrogen atom capable of coordinating to a metal in the ring. Represents
A ₁ , A ₂ , B ₁ and B ₂ each coordinate to M with a substituent or a nitrogen atom. However, A ₁ and A ₂ and are different, and B ₁ and the B ₂ satisfies at least one of the conditions of the different. Y represents a counter ion, and x is a number for maintaining charge balance. (4) The optical recording medium according to the above (3), wherein Y in the formula (1) is a counter cation of a + 1-valent cyanine dye. (5) The optical recording medium according to any one of the above (1) to (3), wherein the recording layer contains a metal complex dye represented by the following formula (2).

[0013]

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[In the formula (2), M represents a metal atom;
A₁₁, A_{twenty one}, B₁₁And B_{twenty one}Are each independently metal
Represents an aromatic ring group having a coordinable 0 in the substituent,
A₁₁, A_{twenty one}, B ₁₁And B_{twenty one}Coordinates O to M. However
A₁₁And A_{twenty one}And B₁₁And B_{twenty one}And
At least one of the different conditions is satisfied.
Y₁ ^{m +}Represents a counter cation having a valence of + m, and m and n represent
1 or 2 respectively. (6) Y in equation (2)₁ ^{m +}Is a + 1-valent cyanine dye
The optical recording medium of the above (5), which is a counter cation of the above.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The optical recording medium of the present invention has a recording layer containing a metal complex dye, and this recording layer has a melting point of −10 ° C. or lower and a coating liquid using a non-halogen alcohol having a boiling point of 80 to 180 ° C. as a solvent. It was painted. Specifically, such a solvent is preferably an aliphatic saturated alcohol having 3 to 6 carbon atoms in total.
It is characterized in that the solution can be coated with an aliphatic saturated alcohol which is environmentally advantageous and has excellent stability.

As a metal complex dye having sufficient solubility in such a solvent, two different polydentate ligands (for example, 3
A metal complex dye to which a (coordination ligand) is coordinated, in particular, an azo metal complex dye. The azo metal complex dye is preferably a compound represented by the following formula (1).

[0017]

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In the formula (1), M represents a metal atom, and A ₁ ,
A ₂ , B ₁ and B ₂ each independently represent an aromatic ring group having a substituent capable of coordinating to a metal, or a nitrogen-containing heteroaromatic ring group having a nitrogen atom capable of coordinating to a metal in the ring; A ₁ ,
A ₂ , B ₁ and B ₂ each coordinate to M at a substituent or a nitrogen atom. However, A ₁ ≠ A ₂ and / or B
₁ ≠ B ₂ . Y represents a counter ion, and x is a number for maintaining charge balance.

The formula (1) will be described in more detail. As the aromatic ring in the aromatic ring group having a substituent capable of coordinating with the central metal represented by A ₁ , A ₂ , B ₁ and B ₂ , It may be a carbocyclic or heterocyclic ring, a monocyclic ring, a condensed polycyclic ring or a polycyclic ring assembly. Examples of such an aromatic ring include a benzene ring, a naphthalene ring, a pyridine ring, a thiazole ring, a benzothiazole ring, an oxazole ring, a benzoxazole ring, a quinoline ring, an imidazole ring, a pyrazine ring, and a pyrrole ring. Ring, naphthalene ring, pyrrole ring is preferred,
Particularly, a benzene ring is preferable.

Examples of the substituent capable of coordinating with the central metal in the aromatic ring group include groups having an active hydrogen before coordinating with the metal, and A ₁ , A ₂ , B ₁ , B The bonding position in the aromatic ring of the group having active hydrogen in ₂ is adjacent to the diazo group, and as the group having active hydrogen, -OH,
—SH, —NH ₂ , and —NHSO ₂ R (where R is 1 carbon atom)
6 alkyl _{group), - COOH, -CONH 2,} -S
O ₂ NH ₂ , —SO ₃ H and the like are mentioned, and —OH is particularly preferable.

The nitrogen-containing heteroaromatic ring in the nitrogen-containing heteroaromatic group having N in the ring that can coordinate to a metal may be a single ring or a condensed polycyclic ring. Specific examples of such a nitrogen-containing heteroaromatic ring include a pyridine ring, a thiazole ring, a benzothiazole ring, an oxazole ring, a benzoxazole ring, a quinoline ring, an imidazole ring, a pyrazine ring, and a pyrrole ring. , A quinoline ring and a thiazole ring are preferred. The position of N in the ring is adjacent to the carbon atom to which the azo group is bonded.

The combination of A ₁ and B ₁ or A ₂ and B ₂ is preferably a combination of benzene rings, a benzene ring and a naphthalene ring, a benzene ring and a pyridine ring, and more preferably a combination of benzene rings.

The aromatic ring group having a substituent capable of coordinating to a metal represented by A ₁ , A ₂ , B ₁ , or B ₂ includes, in addition to an azo group and a substituent capable of coordinating to a metal, A ₁ , A ₂ , B ₁ ,
The nitrogen-containing heteroaromatic ring group having an N capable of coordinating to the metal represented by B ₂ in the ring may further have a substituent in addition to the azo group. Nitro group, cyano group, halogen atom (for example, chlorine atom, bromine atom, etc.),
Carboxyl group, sulfo group, sulfamoyl group (preferably having 0 to 4 carbon atoms, for example, sulfamoyl, methylsulfamoyl and the like), alkyl group (preferably having 1 to 4 carbon atoms)
4, an amino group (preferably having 0 to 10 carbon atoms such as dimethylamino, diethylamino, etc.)
Dibutylamino, phenylamino), and a heterocyclic group (eg, piperidino, morpholino, etc.). Also,
The substituents may be linked to each other to form a ring (for example, a quinolizidine ring (including a partially unsaturated ring) or the like).

When A ₁ , A ₂ , B ₁ and B ₂ are a combination of benzene rings, one of the benzene rings must have a nitro group or a halogen atom (preferably a chlorine atom or a bromine atom) as a substituent. Is particularly preferable, and a nitro group is particularly preferable. Such a nitro group and a halogen atom are preferably present at the meta or para position of the diazo group. Two or more substituents may be present, and in such a case, the substituents may be the same or different. The other benzene ring preferably has an amino group as a substituent, and the amino group may be an unsubstituted amino group or an arylamino group such as phenylamino.
Particularly, a dialkylamino group is preferable, and the total number of carbon atoms of such a dialkylamino group is preferably 2 to 8, for example, dimethylamino, diethylamino, methylethylamino, methylpropylamino, dibutylamino,
Hydroxyethylmethylamino and the like may be mentioned, and the alkyl groups may be connected to each other to form a ring (for example, a piperidine ring, a morpholine ring and the like).

The substitution position of such an amino group is preferably at the para position of the diazo group.

M is a central metal of the metal complex, and the central metal may be any as long as it forms a complex of ligand: metal = 2: 1 (mol). The central metal is Co, Ni, Cu or the like.

A ₁ and A ₂ , or B ₁ and B ₂ , or A
₁ and A ₂ and B ₁ and B ₂ cannot be the same in this combination, and thus the ligand having A ₁ and B ₁
Unlike a ligand having ₂ and B ₂ , the same ligand does not coordinate to the metal. Here, the different ligands include different ones including substituents and the like, and the ring skeleton of the aromatic ring may be the same.

In the formula (1), the group having active hydrogen is an acid anion (when the group having active hydrogen is -OH,-
It coordinates to the central metal in the form of O).

Y represents a counter ion, and x is a number for maintaining charge balance.

As a counter cation, Na⁺, Li⁺,
K⁺, Ca²⁺Inorganic cations such as R₁R _TwoR_ThreeR_FourN⁺, R
₁R_TwoR_ThreeN⁺(CH_Two)_mN⁺R_FourR_FiveR₆(Where R₁,
R_Two, R_Three, R_Four, R_Five, R₆Is a hydrogen atom,
Represents a kill group, an alkoxy group, an aryl group, or the like. m is 2
Represents an integer of 10. ) Represented by ammonium ion,
And cations of a rhodamine dye. other than this,
Preferred as a counter cation is a + 1-valent cyanine dye
Cations. As cations, in particular,
Nin dye cations are preferred.

As the counter anion, a halide ion
(Cl^-, Br^-, I^-Etc.), ClO_Four ^-, BF_Four ^-, P
F₆ ^-, VO_Three ^-, VO_Four ^3-, WO_Four ^2-, CH_ThreeSO_Three ^-, CF_Three
COO^-, CH_ThreeCOO^-, HSO_Four ^-And the like.

As the azo metal complex dye of the present invention, a compound represented by the formula (2) is particularly preferable.

[0033]

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In the formula (2), M is the same as that in the formula (1).
Things. A₁₁, A_{twenty one}, B₁₁, B _{twenty one}Is -O^-Is a substituent
Represents an aromatic ring group contained therein;^-Coordinate to M. Was
But A₁₁≠ A_{twenty one}And / or B₁₁≠ B_{twenty one}And
As in the case of the formula (1), the same ligand is not coordinated.
No. n is 1 or 2, Y₁ ^{m +}Is a + m-valent cation
And m is 1 or 2.

Specific examples of M are the same as those in the formula (1).
Specific examples of the aromatic ring in the aromatic ring group represented by A ₁₁ , A ₂₁ , B ₁₁ , and B ₂₁ are the same as those of the formula (1), and preferred examples are also the same. Y ^{m +} is particularly preferably a ⁺ 1-valent cyanine dye cation.

Hereinafter, specific examples of the cations of the cyanine dye having +1 valence will be shown.

[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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The dye structure represented by the formula (1) is shown below, but the present invention is not limited thereto. Here, it is indicated by a combination of indications such as A ₁ and B ₁ in Expression (1).
The valence of the complex ion is also shown. Also, Me, E in the specific examples
t and Bu represent methyl, ethyl and butyl, respectively.

[0048]

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[0049]

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[0050]

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[0051]

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The azo metal complex of the formula (1) can also be complexed by synthesizing and mixing ligands by known methods.

Further, in order to obtain an azo dye having a cation of a cyanine dye, an azo complex having a Na ⁺ salt or a K ⁺ salt is synthesized, and then an azo complex having a cation of the desired cyanine dye is prepared.
Cyanine dyes I ^- salt and ClO ₄ ^- with a dye salt may be exchanged cations according to known methods.

The dye of the present invention is used as a dye for a recording layer.
One type may be used alone, or two or more types may be used in combination.

These dyes are excellent in light fastness and, because of their structural characteristics of having two different ligands, are significantly different from the azo metal complex in which two identical ligands are coordinated. The solubility in the coating solvent of the invention is increased. The solubility in this case is about 6.0 to 20% by weight, which is sufficient for preparing a dye-containing coating solution.

The coating solvent for forming a recording layer according to the present invention does not attack polycarbonate resin (PC), which is widely used as a substrate material for optical recording media.

In particular, an aliphatic saturated alcohol having 3 to 6 carbon atoms (especially unsubstituted monohydric alcohol) is preferably used as a solvent. Table 1 shows specific examples. The melting point and boiling point are also described. Those having no melting point are liquid substances having a melting point of −10 ° C. or lower.

[0058]

[Table 1]

These solvents may be used as a mixture of two or more kinds. Although it is preferable to use only these solvents, other solvents may be used in combination as long as the amount is 20% by weight or less of the total amount of the solvents.

The concentration of the dye in the coating solution for the recording layer is 0.5 to 4.0% by weight.

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

The recording layer of the optical recording medium of the present invention may contain another type of light absorbing dye in addition to the dye of the present invention. Examples of such a dye include 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. In such a case, the recording layer may be formed by including such a dye in the coating solution.

It is preferable that the other dye used in combination with the dye of the present invention (the case of forming a salt with another dye ion is also included in the dye of the present invention) is 40% by weight or less of the entire dye.

The recording layer is preferably formed by spin coating.

After the spin coating as described above, the coating film is dried if necessary. The thickness of the recording layer formed in this manner is appropriately set according to the target reflectance and the like, but is usually 500 to 3000 A (50 to 3000 A).
300 nm).

The optical recording medium of the present invention is preferably a write-once digital video disc (DVD-R), a write-once compact disc (CD-R), or the like, and a dye is selected and used according to the wavelength used. Can be.

FIG. 1 shows a configuration example of a write-once digital video disc (DVD-R) which performs recording / reproduction at a short wavelength of about 600 to 680 nm, which is an example of a preferred embodiment of the optical recording medium of the present invention. FIG. 1 is a partial sectional view.

As shown in FIG. 1, the optical recording disk 10
Is an optical recording disk conforming to the DVD standard, which is formed by bonding two protective films 15 and 25 of the same structure to each other. The thickness of the adhesive layer 50 is 1
It is about 0 to 200 μm. In this case, the thickness of one substrate (usually, polycarbonate resin) is 0.6 mm, and the recording layer 13 is formed on the substrate 12 having the groove 123.
The reflection layer 14 and the protection film 15 are sequentially formed,
Recording layer 23 and reflection layer 2 on a substrate 22 having
4. A protective film 25 is formed and obtained by bonding as described above. As a bonding method, a hot melt adhesive, a slow-acting UV adhesive, a pressure-sensitive adhesive sheet, or the like can be used.

The substrate 12 or 22 is in the form of a disk. In order to enable recording and reproduction from the back side of the substrate 2, recording light and reproduction light (wavelengths 600 to 680) are used.
substantially transparent (preferably at a transmittance of 88%)
It is preferable to use resin or glass as described above. The size is about 64 to 200 mm in diameter and about 0.6 mm in thickness.

The recording layer 13 or 2 of the substrate 12 or 22
As shown in FIG. 1, tracking grooves 123 or 223 are formed on the surface on which the third member 3 is formed. Groove 12
Preferably, 3 or 223 is a spiral continuous groove having a depth of 0.05 to 0.23 μm (5
00-2300 A), the width is preferably 0.20-0.40 μm, and the groove pitch is preferably 0.65-0.85 μm. By making the groove like this,
A good tracking signal can be obtained without lowering the reflection level of the groove. In particular, the groove width is set to 0.
It is important to limit the thickness to 20 to 0.40 μm. If the groove width is less than 0.20 μm, it is difficult to obtain a tracking signal of a sufficient magnitude, and the jitter becomes large due to a slight offset of tracking during recording. Cheap. Also, as the groove width increases, waveform distortion tends to occur.

The material of the substrate 12 or 22 is preferably resin, and various thermoplastic resins such as polycarbonate resin, acrylic resin, amorphous polyolefin, TPX, and polystyrene resin are suitable. And it can manufacture according to well-known methods, such as injection molding, using such a resin. The groove 123 or 223 is preferably formed when the substrate 12 or 22 is formed. After manufacturing the substrate 12 or 22, a resin layer having the groove 123 or 223 may be formed by a 2P method or the like. In some cases, a glass substrate may be used.

As shown in FIG. 1, the substrate 12 or 2
The recording layer 13 or 23 provided in No. 2 is preferably formed by the spin coating method as described above using the above-mentioned dye-containing coating solution. Spin coating is performed under normal conditions, with a rotation speed of 500 from the inner circumference to the outer circumference.
It may be performed by adjusting the speed between 5000 rpm and the like.

The thickness of the recording layer 13 or 23 thus formed is 50 to 300 nm (500 to 3000 nm).
A), and the complex refractive index at the wavelength of the recording light and the reproduction light is real part n = 2.0 to 2.8 and imaginary part k = 0.4 or less.

If the thickness is outside the above range, the reflectivity decreases, and it becomes difficult to perform good reproduction.

Further, by controlling n and k as described above, good recording and reproduction can be performed. If k exceeds 0.4, a sufficient reflectance cannot be obtained. If n is less than 2.0, the degree of modulation of the signal is too small. Although the upper limit of n is not particularly limited, it is usually about 2.8 for convenience in the synthesis of the dye compound.

The recording layers n and k are determined by forming a recording layer on a predetermined transparent substrate to a thickness of, for example, about 40 to 100 nm under actual conditions, producing a measurement sample, The reflectance is determined by measuring the reflectance of the 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 (635 nm or 650 nm). Also, the transmittance of the sample is measured. Then, from these measured values, n and k may be calculated in accordance with, for example, Kyoritsu Zensho “Optics” Kozo Ishiguro P168-178.

As shown in FIG. 1, a reflective layer 14 or 24 is provided on the recording layer 13 or 23 in close contact with the recording layer. As the reflection layer 14 or 24, Au, Cu,
It is preferable to use a metal or alloy having high reflectivity such as Al, Ag, AgCu, AgPdCu, and AgSb. The thickness of the reflective layer 14 or 24 is preferably 50 nm (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 120 nm (1200 A) or less in consideration of cost, production operation time, and the like. Thereby, the reflectivity of the reflective layer 14 or 24 alone becomes 90% or more, and the reflectivity through the substrate in the unrecorded portion of the medium is sufficient.

As shown in FIG. 1, a protective film 15 or 25 is provided on the reflective layer 14 or 24. The protective film 15 or 25 may be formed of various resin materials such as an ultraviolet curable resin, for example, and usually has a thickness of about 0.5 to 100 μm. The protective film 15 or 25 may be in the form of a layer or a sheet. Protective film 15 or 25
May be formed by an ordinary method such as spin coating, gravure coating, spray coating, dipping, or the like.

For recording or additional recording on the optical recording disk 1 having such a configuration, for example, 635 nm or 650 nm
The recording light of nm is irradiated in a pulse shape through the substrate 12 or 22 to change the light reflectance of the irradiated portion. When the recording light is irradiated, the recording layer 13 or 23 absorbs the light and generates heat, and at the same time, the substrate 12 or 22 is also heated. As a result, in the vicinity of the interface between the substrate 12 or 22 and the recording layer 13 or 23, the material of the recording layer such as a dye is melted or decomposed, and the interface between the recording layer 13 and the substrate 12 or the interface between the recording layer 23 and the substrate 22 is formed. Pressure may be applied and deform the bottom and side walls of the groove.

[0080]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to specific examples of the present invention and comparative examples, but the present invention is not limited to the following examples.

Example 1 Dye I-1 was used as a dye for an optical recording layer, having a pregroove (depth 0.12 μm, width 0.30 μm, groove pitch 0.74 μm), a diameter of 120 mm and a thickness of 0.6 mm.
A recording layer containing a dye was formed to a thickness of 1000 A (100 nm) by spin coating on the polycarbonate resin substrate. In this case, a 1.5 wt% isobutanol solution was used as a coating solution. Next, Au is added to this recording layer.
A reflective layer was formed to a thickness of 850 A by a sputtering method, and a transparent protective film (thickness: 5 μm) of an ultraviolet-curable acrylic resin was further formed. Two disks formed in the same manner were adhered with an adhesive with the protective films facing inward to produce a disk (see FIG. 1). This is designated as Sample No. 1.

In the sample No. 1, the dyes shown in Table 2 were used as dyes for the recording layer in place of the dye I-1, and the respective solvents were used at the respective concentrations. (Table 2).

For the sample thus produced,
After confirming the film formation state and the substrate state after coating, the laser beam 635
A signal was recorded at a linear velocity of 3.5 m / s using nm, and then the disc was reproduced with a 650 nm laser beam at a linear velocity of 3.5 m / s to evaluate the characteristics. In addition, lens aperture diameter NA = 0.60
Met. Characteristics are Jitter, 80 ° C 80% R
The H100 hours reliability test was evaluated. Table 2 shows the results.

[0084]

[Table 2]

From the results in Table 2, it can be seen that the solvent of the present invention does not attack the substrate and dissolves the dye well, so that the film formation state is good, and the jitter is also good, so that it is also excellent as a disk. You can see that. In addition, excellent results were also obtained in the reliability test, and it was found that a disk that could withstand the accelerated test could be formed.

When the above coating solvent was stored for one month and then applied in the same manner as above, the same result was obtained. The results show that the stability as a coating solution is high.

Comparative Example 1 In the same manner as in Example 1, a disk was formed in which the dye and the coating solvent were changed as shown in Table 3. With respect to the sample thus manufactured, the state of film formation and the state of the substrate after application were confirmed in the same manner as in Example 1, but none was satisfactory.

[0088]

[Table 3]

[0089]

According to the present invention, the laser-absorbing dye can be dissolved in a high concentration, the life of the coating solvent is long, the substrate is not damaged, the film-forming property is good, and the cost is low. By using a coating solvent which does not adversely affect the performance, a disk having excellent characteristics and good storage stability can be formed.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an example of an optical recording disk of the present invention.

[Explanation of symbols]

 Reference Signs List 10 optical recording disk 12, 22 substrate 123, 223 groove 13, 23 recording layer 14, 24 reflection layer 15, 25 protective film 50 adhesive layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masahiro Shinkai 1-13-1, Nihonbashi, Chuo-ku, Tokyo TDK Corporation F-term (reference) 2H111 FA37 FB42 FB43 GA05 GA07 5D029 JA04

Claims (6)

[Claims] A recording layer containing a dye on a substrate,
In an optical recording medium that performs recording by forming pits by irradiating light, the recording layer contains a metal complex dye in which two different polydentate ligands are coordinated, and has a melting point of −10 ° C. or lower. With a boiling point of 80
An optical recording medium formed by applying a coating solution using a non-halogen alcohol at -180 ° C as a solvent. 2. A non-halogenated alcohol having a total carbon number of 3
The optical recording medium according to claim 1, which is an aliphatic saturated alcohol of (1) to (6). 3. The optical recording medium according to claim 1, wherein the recording layer contains a metal complex dye represented by the following formula (1). Embedded image [In the formula (1), M represents a metal atom, and A ₁ , A ₂ , B _1, and B ₂ each independently represent an aromatic ring group having a substituent capable of coordinating to a metal, or coordinating to a metal. A ₁ , A ₂ , B ₁
And B ₂ are each coordinated to M at a substituent or a nitrogen atom. However, A ₁ and A ₂ are different, and B ₁
And the B ₂ satisfies at least one of the conditions of the different. Y represents a counter ion, and x is a number for maintaining charge balance. ] 4. The optical recording medium according to claim 3, wherein Y in the formula (1) is a counter cation of a + 1-valent cyanine dye. 5. The recording layer is represented by the following formula (2).
4. The optical recording device according to claim 1, which contains a metal complex dye.
Recording medium. Embedded image[In the formula (2), M represents a metal atom;₁₁, A_{twenty one}, B₁₁
And B_{twenty one}Represent 0 that can be independently coordinated to the metal
Represents an aromatic ring group contained in the substituent,₁₁, A_{twenty one}, B ₁₁And
And B_{twenty one}Coordinates O to M. However, A₁₁And A_{twenty one}Is different
Becoming and B₁₁And B_{twenty one}Of the differences
At least one condition is satisfied. Y₁ ^{m +}Is + m valence
And m and n are each 1 or 2
You. ] 6. The optical recording medium according to claim 5, wherein Y ₁ ^{m +} in the formula (2) is a counter cation of a + 1-valent cyanine dye.