JP2001219650A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium having excellent recording reproducing characteristics, such as a sufficient solubility to a coating solvent, a nature which will not invade a polycarbonate substrate, good jitter shown to a light having the wavelength of 680 nm or less or the like, and, further, prominent in resistance to light as well as reliability. SOLUTION: The optical recording medium whose wavelength of the recording and/or reproducing light is specified so as to be 680 nm or less, is provided on a substrate with a recording layer containing a dyestuff, and a reflection layer provided on the recording layer to effect recording by forming pits by the irradiation of light. The recording layer contains the metal complex dyestuff of azatrimethine dyestuff and a metal, which is shown by the formula (I). In the formula (I), A and B show an atomic group for completing a heterocycle while R shows hydrogen atom or a monovalent substituent group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium having a reflective layer, preferably formed with a laser beam to form pits. In particular, the recording / reproducing wavelength is 600-680
nm optical recording medium.

[0002]

2. Description of the Related Art The present inventors have developed a CD-R (write-once compact disc) as a recordable optical recording medium conforming to the CD (compact disc) standard. This CD-R is composed of an optical recording layer made of an organic dye, a light reflection layer made of a metal, and a protective layer made of a UV curable resin on a substrate having a guide groove, and is recorded and reproduced by a laser having a wavelength of 780 nm. be able to.

On the other hand, in recent years, a higher-density optical recording medium using laser light having a shorter wavelength than the conventional 780 nm laser has been desired. One of the proposals is to reduce the recording / reproducing wavelength from 635 nm to 650 nm.
R.

With this wavelength change, it is necessary to shorten the absorption wavelength of the organic dyes used in the recording layer. However, currently proposed organic dyes have insufficient electrical characteristics when formed into a disc, and particularly have a problem in recording. It has problems of poor sensitivity and jitter, and insufficient light resistance and reliability.

As dyes used in the recording layer, azo dyes and indolenine cyanine dyes have been proposed from the viewpoint of optical characteristics. Japanese Patent Application Laid-Open No. 62-30090 proposes an optical recording medium in which a recording layer contains a metal chelate compound of an azo compound and a metal, but has low solubility and is sufficiently soluble in a coating solvent that does not attack the polycarbonate substrate. It has the disadvantage that it has no properties.

On the other hand, indolenine-based cyanine dyes have a drawback that reproduction deterioration due to repeated irradiation of reproduction light and light deterioration during storage in a bright room are apt to occur. For this reason, it has been proposed to use a mixture of a dye and a metal complex quencher, or to use a dye cation and a quencher anion by ionic bonding as a conjugate (JP-A-60-118748).
No., No. 60-118749).

However, in this system, the solubility in a coating solvent used during spin coating is significantly reduced,
There is a disadvantage that the stabilizer itself is decomposed and deteriorated.

Japanese Patent Publication No. 7-51682 proposes an optical recording medium in which a recording layer contains a metal chelate compound of an azo compound and a metal and an indolenine cyanine dye, but has a long absorption wavelength of 635 nm to 650 nm. So enough modulation depth,
There is a problem that reflectance cannot be obtained.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to have excellent recording / reproducing characteristics, such as having sufficient solubility in a coating solvent which does not attack a polycarbonate substrate and exhibiting a good jitter at a wavelength of 680 nm or less. It is to provide an optical recording medium. Another object is to provide an optical recording medium having excellent light resistance and reliability.

[0010]

This and other objects are achieved by the following (1) and (2). (1) The recording and / or reproducing light has a wavelength of 680 nm or less, has a recording layer containing a dye on a substrate, has a reflective layer on the recording layer, and forms a pit by irradiating light. An optical recording medium in which recording is performed by using a recording medium, wherein the recording layer contains a metal complex dye of a dye represented by the following formula (I) and a metal.

[0011]

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[In the formula (I), A and B each represent a group of atoms necessary for forming a heterocyclic ring together with the carbon atom and the nitrogen atom to which they are bonded;
Alternatively, the heterocyclic skeletons completed by B may be the same or different. R represents a hydrogen atom or a monovalent substituent, but R may form a part of A or B with a heterocyclic ring. (2) The optical recording medium according to (1), wherein the recording layer further contains a light absorbing dye different from the metal complex dye. (3) The optical recording medium according to (2), wherein the light absorbing dye is a trimethine cyanine dye represented by the following formula (II).

[0013]

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In the formula (II), Q ₁ and Q ₂ each represent an atom group necessary for forming a heterocyclic ring together with a carbon atom and a nitrogen atom, and the heterocyclic skeleton completed by Q ₁ or Q ₂ is They may be the same or different. R ₁₁ and R ₁₂ each represent an aliphatic hydrocarbon group, which may be the same or different. R ₁₃ represents a hydrogen atom or a monovalent substituent. X ^- represents a monovalent anion. ]

[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 and / or reproduction light wavelength of 680 nm or less, has a reflective layer on a recording layer, and forms a small hole called a pit by light irradiation to perform recording. The recording layer contains a metal complex dye of the dye represented by the formula (I) and a metal.

[0016]

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In the formula (I), A and B each represent a group of atoms necessary to form a heterocyclic ring together with the carbon atom and the nitrogen atom to which they are bonded. It may be a polycyclic ring such as a polycyclic ring, and is preferably a 5- or 6-membered ring which may have a condensed ring. The heterocyclic skeleton completed by A or B may be the same or different.

Examples of such a heterocyclic ring include a pyrrole ring, a pyrazoline ring, a thiazole ring, a benzothiazole ring, a naphthothiazole ring, an oxazole ring, a benzoxazole ring, a naphthooxazole ring, a selenazole ring, a benzoselenazole ring, and a naphthol ring. Selenazole ring, thiazoline ring, oxazoline ring, selenazoline ring, quinoline ring, isoquinoline ring, indole ring, benzoindole ring, indolenine ring, benzoindolenine ring, pyridine ring, imidazole ring, benzimidazole ring, quinoxaline ring, isoindole Ring, isoindolenine ring, isoindoline ring, thiadiazole ring and the like.

Of these, a thiazole ring, a benzothiazole ring, a quinoline ring, an indolenine ring, a pyridine ring and a thiadiazole ring are preferred.

These heterocycles may have a substituent. Examples of the substituent include an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an aralkyl group, a halogen atom, a cyano atom, Group, nitro group, ester group, carbamoyl group, amino group, acyl group, acylamino group, sulfamoyl group,
Examples thereof include a sulfonamide group, and these substituents may further have a substituent. Further, the heterocyclic ring may form a cyclic ketone.

The alkyl group is preferably one having a total of 1 to 12 carbon atoms, and may be linear or branched, and in some cases, may have a cycloalkyl group or a cycloalkyl group. You may. Further, it may have a substituent, and such a substituent is preferably a halogen atom (such as a fluorine atom or a chlorine atom). In particular,
Alkyl groups which may have a straight-chain or branched substituent having 1 to 4 carbon atoms are preferred, and specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl and isobutyl. Group, s-butyl group, t-butyl group, trifluoromethyl group and the like.

The alkoxy group preferably has 1 to 4 carbon atoms in the alkyl moiety, and may be substituted with a halogen atom (such as a fluorine atom). Specific examples of such an alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, and a pentafluoropropoxy group.

Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.

The amino group preferably has a substituent, but may be unsubstituted. The substituted amino group is particularly preferably a dialkylamino group. In this case, the alkyl portion of the dialkylamino group has 1 to 1 carbon atoms.
2, preferably 1 to 4, and may be linear or branched. Also, the two alkyl groups may be asymmetric. Specific examples of the amino group include an amino group, a methylamino group, a dimethylamino group, a diethylamino group, a dipropylamino group, and a dibutylamino group. Further, the substituents of the amino group may be bonded to each other to form a nitrogen-containing heterocyclic ring, and examples thereof include a piperidine ring.

The aryl group preferably has 6 to 12 carbon atoms, may be a single ring or a polycyclic ring such as a condensed polycyclic ring, and may be substituted with a halogen atom (eg, a chlorine atom or a bromine atom). You may. Specific examples of such an aryl group include a phenyl group, a chlorophenyl group, and a bromophenyl group. The aryloxy group preferably has 6 to 12 carbon atoms in the aryl moiety, and may have a substituent. Specific examples include a phenoxy group.

The alkylthio group preferably has 1 to 4 carbon atoms in the alkyl moiety, and may have a substituent. Specific examples thereof include a methylthio group and an ethylthio group.

The arylthio group preferably has 6 to 12 carbon atoms in the aryl moiety, and may have a substituent. Specific examples include a phenylthio group.

The aralkyl group has a total carbon number of 7-1.
2 are preferable and may have a substituent, and specific examples include a benzyl group and a phenethyl group.

The ester group has a total carbon number of 2 to 12
Are preferred, and may have a substituent. Specific examples thereof include a methoxycarbonyl group, an ethoxycarbonyl group, an acetoxy group, and a benzoyloxy group.

The carbamoyl group has a total carbon number of 1 to 1.
12 are preferable, and may have a substituent. Specific examples thereof include a carbamoyl group, a methylcarbamoyl group,
And a phenylcarbamoyl group.

The acyl group preferably has a total of 1 to 12 carbon atoms and may have a substituent. Specific examples include an acetyl group and a propionyl group.

The acylamino group has a total carbon number of 1 to 1.
Twelve are preferred, and may have a substituent. Specific examples include an acetylamino group and a benzylamino group.

The sulfamoyl group has a total carbon number of 0
To 12 are preferable, and may have a substituent,
Specific examples include a sulfamoyl group, a methylsulfamoyl group, and a phenylsulfamoyl group.

The sulfonamide group preferably has a total of 0 to 12 carbon atoms and may have a substituent. Specific examples include a methylsulfonamide group and a benzenesulfonamide group.

Two or more of these substituents may be present, and when they are two or more, they may be the same or different. Further, adjacent substituents are bonded to each other to form a condensed ring. May be.

R represents a hydrogen atom or a monovalent substituent.
Examples of the monovalent substituent represented by R include an alkyl group, an alkenyl group, an aryl group, a halogen atom, a cyano group, a nitro group, a carbamoyl group, an alkoxycarbonyl group, an acyl group, a heterocyclic group, and an arylazo group. Can be

The alkyl group preferably has a total of 1 to 12 carbon atoms, and may be linear or branched. In some cases, the alkyl group has a cycloalkyl group or a cycloalkyl group. You may. Further, it may have a substituent, and such a substituent is preferably a halogen atom (such as a fluorine atom or a chlorine atom). In particular,
Alkyl groups which may have a straight-chain or branched substituent having 1 to 4 carbon atoms are preferred, and specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl and isobutyl. Group, s-butyl group, t-butyl group, trifluoromethyl group and the like.

The alkenyl group includes 2 to 12 carbon atoms in total.
Are preferred, and may be linear or branched, and may further have a substituent.As such a substituent, a cyano group or the like is preferable, and specifically, And a vinyl group and a tricyanovinyl group.

The aryl group preferably has 6 to 12 carbon atoms, may be a single ring or a polycyclic ring such as a condensed polycyclic ring, and is substituted with a halogen atom (eg, a chlorine atom or a bromine atom). You may. Specific examples of such an aryl group include a phenyl group, a chlorophenyl group, and a bromophenyl group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and the like.

The carbamoyl group has a total carbon number of 1 to
12 are preferable, and may have a substituent. Specific examples thereof include a carbamoyl group, a methylcarbamoyl group,
And a phenylcarbamoyl group.

The alkoxycarbonyl group preferably has 2 to 12 carbon atoms and may have a substituent. Specific examples thereof include a methoxycarbonyl group and an ethoxycarbonyl group.

The acyl group preferably has 1 to 12 carbon atoms and may have a substituent. Specific examples thereof include an acetyl group and a propionyl group.

The heterocyclic group may further have a substituent, and specific examples include a pyridyl group.

The arylazo group may further have a substituent.

R may form a part of a heterocyclic ring with A or B.

R represents a hydrogen atom, a cyano group, a nitro group, an alkoxycarbonyl group, a heterocyclic group, an aryl group,
Alkenyl groups are preferred.

The central metal of the metal complex dye obtained by coordinating the compound represented by the formula (I) is Co, Ni, Cu,
Mn, Cr, etc., and particularly preferred are Co, Ni, and Cu.

The compound represented by the formula (I) is a tridentate ligand and forms a 1: 1 complex or a 1: 2 complex with a metal.

When the coordination number of the central metal cannot be satisfied only by the ligands of the compound represented by the formula (I), other ligands may be coordinated in addition to the above compounds. Such other ligands include a chlorine atom, a water molecule, hydroxo and the like, and these ligands are derived from a raw material or a reaction solvent.

When the metal complex dye has an electric charge, the counter ion includes chloride ion (Cl ⁻ ), bromide ion (Br ⁻ ), iodide ion (I ⁻ ), and tetrafluoroborate ion (BF ₄ ^-), hexafluorophosphate ion (PF ₆ ^-), hexafluoroantimonate ion (S
bF ₆ ⁻ ), tetraphenylborate ion (B (C ₆ H ₅ )
₄ ^-), perchlorate ion (ClO ₄ ^-), tungstate ions (WO ₄ ^2-), and the like.

Hereinafter, specific examples of the metal complex dye used in the present invention will be shown by a combination of the compound represented by the formula (I), a central metal and a counter ion. The compound of formula (I) is -N
The active hydrogen of H is removed. Pr represents a propyl group, and Ph represents a phenyl group.

[0053]

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[0054]

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[0055]

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[0056]

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The following shows a synthesis example.

Synthesis Example 1 Dye No. Synthesis of 3 [Synthesis of ligand] DMF (dimethylformamide) 15
8.7 g of 2-benzothiazolylacetonitrile was dissolved in 0 ml and coupled with a diazonium solution prepared by a conventional method from 7.5 g of 2-aminobenzothiazole.
The resulting precipitate was filtered, washed and dried to obtain 12.6 g of (benzothiazol-2-ylazo) benzothiazol-2-ylacetonitrile.

[Synthesis of Complex] 2.68 g of this ligand was added to T
Dissolve in 32 ml of HF (tetrahydrofuran)
1.05 g of nickel acetate dissolved in 16 ml of methanol was added. After refluxing for 3 hours, methanol was added to precipitate a complex, which was filtered, washed with methanol, and dried to obtain 2.04 g of a complex dye (No. 3). (Yield 75.0%).

Mass spectrometry value (M +): 728 Other exemplified compounds were synthesized and identified in the same manner as described above.

Melting point (mp) of the metal chelate compound of the present invention
Is 190-330 ° C., and λmax (measured with a 50 nm thick dye film) is in the range of 500-620 nm.

The real part (n) of the complex refractive index at a wavelength of 635 nm or 650 nm is 1.90 to 2.50, and the imaginary part (k) is
0 to 0.25.

The dyes n and k are determined by forming a dye film on a predetermined transparent substrate to a thickness of about the recording layer of an optical recording medium, for example, 40
A layer having a thickness of about 100 nm was formed under the same conditions as the recording layer to prepare a measurement sample.
Measure the reflectance and transmittance at 5 nm or 650 nm,
From these measured values, for example, it is calculated according to Kyoritsu Zensho "Optics" Kozo Ishiguro, pages 168 to 178. The reflectance is the reflectance of the measurement sample through the substrate or the reflectance from the dye film side, and is measured by specular reflection (about 5 °).

The metal complex dye of the present invention may be used alone or as a combination of two or more dyes for the recording layer.

These metal complex dyes have excellent light fastness,
It has a quencher function, has sufficient solubility in organic solvents, and has sufficient solubility in a coating solvent that does not attack polycarbonate resin (PC), which is widely used as a substrate material for optical recording media.

The recording layer using these dyes is particularly preferably used for a write-once optical recording disk (DVD-R). Such a recording layer can be formed using a dye-containing coating solution. In particular, it is preferable to use a spin coating method in which the coating solution is spread and applied on a rotating substrate. In addition, gravure coating, spray coating, dipping, or the like may be used.

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 50 to 300 nm (500 to 3000 °).

The pigment content in the coating solution is usually
The content is preferably 0.05 to 10% by mass. Since the metal chelate compound of the present invention has good solubility, it is easy to prepare a coating solution having such a content. Specifically, the metal chelate compound of the present invention is used in alcohols, cellosolves or alkoxy alcohols, keto alcohols such as diacetone alcohol, fluorinated alcohols such as 2,2,3,3-tetrafluoropropanol, etc. 1
0% by mass is dissolved. Dissolves 1% by mass or more in ethyl cellosolve or 2,2,3,3-tetrafluoropropanol, which is a suitable coating solvent especially when applied to a polycarbonate disk substrate, and forms a high-quality spin-coated film in a short time. It is possible to

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

Of these, alcohols are particularly preferred. Among alcohols, alkoxy alcohols and keto alcohols are preferred. In the alkoxy alcohol system, the alkoxy portion preferably has 1 to 4 carbon atoms, and the alcohol portion preferably has 1 to 5 carbon atoms, more preferably 2 to 5 carbon atoms, and has a total carbon atom of 3 To 7 is preferable. Specifically, ethylene glycol monoalkyl ether (cellosolve) such as ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (also referred to as ethyl cellosolve or ethoxyethanol), butyl cellosolve, and 2-isopropoxy-1-ethanol
System or 1-methoxy-2-propanol, 1-methoxy-
2-butanol, 3-methoxy-1-butanol, 4-
Methoxy-1-butanol, 1-ethoxy-2-propanol and the like can be mentioned. Examples of keto alcohols include diacetone alcohol. Furthermore, 2,2,3,3-
Fluorinated alcohols such as tetrafluoropropanol can also be used.

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

The recording layer of the optical recording medium of the present invention may contain another type of light absorbing dye in addition to the metal complex dye of the present invention. Examples of such a dye include a metal complex-based dye, a cyanine dye, a styryl-based dye, a porphyrin-based dye, and a formazan metal complex other than those described above.
Specifically, a trimethine cyanine dye is preferable.

In particular, a trimethine cyanine dye represented by the formula (II) is preferable.

[0074]

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Referring to the formula (II), Q ₁ and Q ₂ may be the same or different from each other, and are each formed to form a 5-membered nitrogen-containing heterocyclic ring which may have a condensed ring. Represents a group of atoms. Such heterocycles include indolenine ring, 4,5-benzoindolenine ring,
Oxazoline ring, thiazoline ring, selenazoline ring, imidazoline ring and the like. Particularly, an indolenine ring and a 4,5-benzoindolenine ring are preferred.

These rings may have a substituent. Examples of such a substituent include a halogen atom, an alkyl group, an alkoxy group, an aryl group, an acyl group, an amino group and a nitro group. is there.

R ₁₁ and R ₁₂ each represent an aliphatic hydrocarbon group, preferably an alkyl group. The alkyl group may have a substituent, and preferably has 1 to 5 carbon atoms. Examples of the substituent include a halogen atom, an alkyl group, and an ether group.

R ₁₃ represents a hydrogen atom, a monovalent substituent such as a halogen atom or an alkyl group.

[0079] X ^- represents a monovalent anion, specifically a halide ion ^{(Cl -, Br -, I} - , etc.), ClO ₄
^- , BF _4- ^{and the} like.

Hereinafter, specific examples of the trimethine cyanine dye will be described.

[0081]

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[0082]

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Some of these cyanine dyes are commercially available, and can be easily synthesized by a known method (described in JP-A-58-112790, etc.).

The addition of the metal complex dye of the present invention to the trimethine cyanine dye is very effective in improving light resistance. The mixing ratio of the metal complex dye of the present invention and the trimethine cyanine dye is preferably such that the molar ratio of the metal complex dye / trimethine cyanine dye of the present invention is 90/10 to 30/70.

The cyanine dyes may be used alone or in combination of two or more.

This is a preferred embodiment of the optical recording medium of the present invention.
FIG. 1 shows a configuration example of a write-once optical recording disk (DVD-R) that performs recording / reproduction at a short wavelength of about 600 nm to 680 nm. FIG.
Is a partial sectional view.

As shown in FIG. 1, the optical recording disk 1
Is an optical recording disk conforming to the DVD standard, which is formed by bonding two protective films 5 with an adhesive layer 6 between two disks having the same structure. The thickness of the adhesive layer 6 is about 10 to 200 μm. In this case, the thickness per substrate (usually polycarbonate resin) is 0.6mm
The recording layer 3, the reflective layer 4, and the protective film 5 are sequentially formed on the substrate 2 having the groove 23. On the other hand, a disk having the same configuration is obtained in the same manner, and these are bonded together as described above. It is something that can be done. 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 2 is in the form of a disk. To enable recording and reproduction from the back side of the substrate 2,
Substantially transparent (preferably at a transmittance of 88%) with respect to recording light and reproduction light (wavelength of 600 to 680 nm, furthermore, about 630 to 680 nm, especially about 635 to 680 nm, particularly 635 nm or 650 nm). It is preferable to use resin or glass as described above. The size is 64 to 20 in diameter
It should be about 0mm and about 0.6mm thick.

As shown in FIG. 1, a tracking groove 23 is formed on the surface of the substrate 2 on which the recording layer 3 is formed.
The groove 23 is preferably a spiral continuous groove having a depth of 0.05 to 0.20 μm (500 to 2000 μm).
Å), width 0.20 ~ 0.40μm, groove pitch 0.65 ~ 0.
It is preferably 85 μm. With such a configuration of the groove, a good tracking signal can be obtained without lowering the reflection level of the groove.
In particular, it is important to regulate the groove width to 0.20 to 0.40 μm.If the groove width is less than 0.2 μm, it is difficult to obtain a tracking signal of sufficient magnitude, and jitter due to a slight offset of tracking during recording. Easy to grow. Also, as the groove width increases, the influence of adjacent tracks increases, and waveform distortion tends to occur.

For the material of the substrate 2, it is preferable to use a 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 group 23 is preferably formed when the substrate 2 is formed. After the manufacture of the substrate 2, a resin layer having the groove 23 may be formed by a 2P method or the like. In some cases, a glass substrate may be used.

As shown in FIG. 1, the recording layer 3 provided on the substrate 2 is formed by using the above-mentioned dye-containing coating solution and preferably by the spin coating method as described above. The spin coating may be performed under normal conditions, for example, by adjusting the number of revolutions from 500 to 5000 rpm from the inner circumference to the outer circumference.

The thickness of the recording layer 3 thus formed is 50 to 300 nm (500 to 3000 °), the complex refractive index at the recording light and reproduction light wavelengths is real part n = 2.0 to 2.8, and imaginary part. k == 0.4 or less.

If the thickness is out of the above range, the contrast between the groove portion and the land portion becomes small, making it difficult to perform tracking, or the reflectivity is lowered, making it 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. The upper limit of n is not particularly limited, but is usually about 2.8 from the viewpoint of the synthesis of the dye compound. The lower limit of k is not particularly limited, but is about 0.

Incidentally, n and k of the recording layer were determined by forming the 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 determined by the recording / reproducing light wavelength (635 nm or 650 nm).
m) by specular reflection (about 5 °). Also, the transmittance of the sample is measured. And from these measured values, for example, Kyoritsu Zensho "Optics" Kozo Ishiguro P168-17
According to 8, n and k may be calculated.

As shown in FIG. 1, on the recording layer 3,
The reflection layer 4 is provided in close contact with the substrate. The reflective layer 4 is preferably made of a high-reflectance metal or alloy such as Au, Cu, Al, Ag, and AgCu. The thickness of the reflection layer 4 is 50
The thickness is preferably nm (500 °) or more, and the layer may be formed by vapor deposition, spak, or the like. Although there is no particular upper limit on the thickness, considering cost, production work time, etc.
It is preferably about 0 nm (1200 °) or less. Thereby, the reflectivity of the reflective layer 4 alone becomes 90% or more, and the reflectivity through the substrate of the unrecorded portion of the medium is sufficient.

As shown in FIG. 1, on the reflection layer 4,
A protective film 5 is provided. The protective film 5 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 5 may be in the form of a layer or a sheet. The protective film 5 is formed by spin coating,
It may be formed by a usual method such as gravure coating, spray coating, dipping or the like.

In order to perform recording or additional recording on the optical recording disk 1 having such a configuration, recording light of, for example, 635 nm or 650 nm is irradiated in a pulse shape through the substrate 2 to change the light reflectance of the irradiated portion. When the recording light is irradiated, the recording layer 3 absorbs the light and generates heat, and at the same time, the substrate 2 is also heated. As a result, in the vicinity of the interface between the substrate 2 and the recording layer 3, melting or decomposition of the recording layer material such as a dye occurs, and
Pressure may be applied to the interface between the groove and the substrate 2 to deform the bottom and side walls of the groove.

[0099]

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

Example 1 Dye No. 3 was used as a dye for an optical recording layer, and a pregroove (depth 0.18 μm, width 0.28 μm, groove pitch 0.74 μm) was used.
A recording layer containing a dye was formed by a spin coating method on a polycarbonate resin substrate having a diameter of 120 mm and a thickness of 0.6 mm having m). In this case, the coating liquid is 1.0 mass%
2,2,3,3-tetrafluoropropanol solution was used. Next, an Ag reflective layer was formed on this recording layer to a thickness of 85 nm (850 °) by a sputtering method, and a transparent protective film (5 μm thick) of an ultraviolet-curable acrylic resin was 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 referred to as Sample No. Set to 1.

The sample No. In No. 1, dye No. 1 was used as a dye for the recording layer. Samples were prepared in the same manner except that the dyes shown in Table 1 were used instead of 3 (Table 1).

Example 2 As a dye for an optical recording layer, Dye No. 1 and cyanine dye No.A
Except that a mixture of -9 at a molar ratio of 50:50 is used.
A sample was produced in the same manner as in Example 1.

This is referred to as Sample No. 11 is assumed.

The sample No. In No. 11, dye No. 1 was used as a dye for the recording layer. 1 and cyanine dye No. 1 A sample was prepared in the same manner except that a dye mixture as shown in Table 2 was used instead of the mixture of A-9 (Table 2).

The laser light 6 was applied to the samples Nos. 1 to 20 (Tables 1 and 2) of Examples 1 and 2 thus manufactured.
An 8/16 modulated signal was recorded at a linear velocity of 3.5 m / s using 50 nm. The optimum recording power means a range where the asymmetry is 0% with an evaluation machine (manufactured by Pulstec) used for recording evaluation. Next, this disk was drawn at 650 nm with a linear velocity of 3.5 m / s.
Reproduction was performed with laser light, and the characteristics were evaluated. The numerical aperture of the objective lens is NA = 0.60. The characteristics are reflectance at 650 nm, degree of modulation (I14 Mod.), Jitter (Jitter), and 650.
The optimum recording power (Po) in nm was evaluated.

Further, the above sample No. Light resistance was adjusted for 1 to 20. The light fastness was determined by irradiating a xenon lamp (Xenon fade meter manufactured by Shimadzu Corporation) of 80,000 lux for 40 hours and then measuring the jitter of the disk.

Further, the above sample No. For 1 to 20, a reliability test was performed at 80 ° C. and 80% RH for 500 hours.

Tables 1 and 2 show the results.

[0110]

[Table 1]

[0111]

[Table 2]

From the results shown in Tables 1 and 2, it can be seen that the reflectance, the degree of modulation and the jitter are all good. In particular, sample N
o. As can be seen from 11 to 20, when the mixture of the metal complex dye of the present invention and the trimethine cyanine dye was used as the optical recording layer dye, it was found that better jitter was exhibited.

According to the light resistance test, the sample No.
For 1-20, the change in jitter was very small. The level was much better than the sample using the trimethine cyanine dye shown in Comparative Example 1 below. Sample No. using a mixture of the metal complex dye of the present invention and a trimethine cyanine dye. Very good results were obtained even at 11-20, with little change in jitter. This indicates that the metal complex dye of the present invention has an excellent quencher function.

Further, according to the reliability test, the sample N
With respect to o.1 to 20, the characteristics were good with almost no deterioration of the characteristics. The level was much better than the sample using the trimethine cyanine dye shown in Comparative Example 1 below.

Comparative Example 1 A disk sample was prepared in the same manner as in Sample No. 1 except that only the cyanine dye (dye No. A-10) was used, and the initial characteristics, light resistance and reliability were obtained in the same manner as described above. Was evaluated.

Comparative Example 2 An azo metal complex R-1 having the following structure described in JP-A-7-51682 was used in place of the azo metal complex of the present invention.
Sample No. A disk sample was prepared in the same manner as in Example 11, and the initial characteristics, light resistance, and reliability were evaluated in the same manner as described above.

[0117]

Embedded image

Table 3 shows the results of these comparative examples.

[0119]

[Table 3]

In the sample of Comparative Example 1, sufficient light fastness was not obtained, and jitter could not be measured. Also in the reliability test, the degree of modulation and the deterioration of jitter were large.

The sample of Comparative Example 2 had poor recording sensitivity and large jitter. Also in the light resistance test and the reliability test, the degree of modulation and the deterioration of jitter were large.

[0122]

According to the present invention, by using the metal complex dye of the present invention having excellent solubility as an optical recording layer, characteristics such as excellent balance of recording sensitivity, reflectance and modulation and small jitter can be obtained. An optical recording medium excellent in quality can be obtained. In particular, when a mixture of the metal complex dye of the present invention and a trimethine cyanine dye is used, the jitter is further improved.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical recording disk 2 Substrate 23 Group 3 Recording layer 4 Reflection layer 5 Protective film 6 Adhesion layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C09B 29/44 G11B 7/24 516 G11B 7/24 516 B41M 5/26 Y (72) Inventor: Emiko Kobe Tokyo 1-13-1 Nihombashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Masahiro Shinkai 1-13-1, Nihonbashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Seishi Sasaki Chuo-ku, Tokyo Nihonbashi Bakurocho 1-7-6 Dainichi Seika Kogyo Co., Ltd. (72) Inventor Shiro Yamamiya Nihonbashi Bakurocho 1-7-6 Nihonbashi Bakurocho Dainichi Seika Kogyo Co., Ltd. (72) Inventor Yoshio Abe Tokyo 1-7-6, Nihonbashi Bakurocho, Chuo-ku F-term (reference) 2H111 EA03 EA12 EA22 EA2 5 EA37 EA39 EA43 EA44 FA01 FA12 FB42 FB43 4H056 CA01 CC02 CC08 CE03 DD03 FA06 5D029 JA04 JC17 JC20

Claims (3)

[Claims] 1. A recording and / or reproducing light having a wavelength of 68
0 nm or less, having a recording layer containing a dye on the substrate, having a reflective layer on the recording layer, forming a pit by irradiating light to perform recording, wherein the recording An optical recording medium, wherein the layer contains a metal complex dye of a dye represented by the following formula (I) and a metal. Embedded image [In the formula (I), A and B each represent a group of atoms necessary to form a heterocyclic ring together with the carbon atom and the nitrogen atom to which they are bonded, and are completed by A or B The heterocyclic skeletons may be the same or different. R represents a hydrogen atom or a monovalent substituent, but R may form a part of A or B with a heterocyclic ring. ] 2. The optical recording medium according to claim 1, wherein the recording layer further contains a light absorbing dye different from the metal complex dye. 3. The optical recording medium according to claim 2, wherein the light absorbing dye is a trimethine cyanine dye represented by the following formula (II). Embedded image [In the formula (II), Q ₁ and Q ₂ each represent a group of atoms necessary to form a heterocyclic ring together with a carbon atom and a nitrogen atom, and the heterocyclic skeletons completed by Q ₁ or Q ₂ are the same or different. It may be something. R ₁₁ and R ₁₂ each represent an aliphatic hydrocarbon group, which may be the same or different. R ₁₃ represents a hydrogen atom or a monovalent substituent. X ^- represents a monovalent anion. ]