JP3005111B2 - Optical recording medium, information recording method, and method of manufacturing optical recording medium - Google Patents

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, and more particularly to a record blank suitable for recording information with a laser beam, particularly a semiconductor laser beam, and optically reproducing information recorded by the laser beam. For possible information records.

[0002]

2. Description of the Related Art Generally, an optical recording medium such as an optical disk or an optical card has small, optically detectable (for example, about 1 μm) pits formed in a spiral, concentric or linear track on a recording layer formed on a substrate. By recording in such a manner that information is formed, information can be accumulated at a high density.

As a method of optically recording, for example, “Optical engineering (Opti
cal Engineering, Vol. 15N
o. 2 March-April 1976 pp99
By irradiating the recording layer of the optical recording medium with a light beam, for example, a laser beam, as described in 〜- 」, a type that causes deformation or holes in the recording layer, a type that forms bubbles, a phase change or discoloration, Types that cause bleaching and the like are known.

As a material used for a recording layer of an optical recording medium for performing such recording, for example, an inorganic substance such as a metal thin film such as an aluminum vapor-deposited film, a bismuth thin film, a tellurium oxide thin film, or a chalcogenite-based amorphous glass film is used. The main ones have been proposed. These thin films are generally sensitive to light having a wavelength of about 350 to 800 nm, and have a high reflectance to laser light, and thus have disadvantages such as low utilization of laser light.

[0005] Further, such an inorganic substance is usually formed into a recording layer by forming a film by a method such as vapor deposition or sputtering. However, such a film forming method requires a large-scale production line equipped with a vacuum system, and is costly. There was also a drawback in terms of lowering

For these reasons, research on optical recording media using an organic dye compound capable of changing optical properties with light energy of a relatively long wavelength (for example, 780 nm or more) has been made energetically in recent years. ing. An optical recording medium using such an organic dye has, for example, an oscillation wavelength of 780 nm.
Alternatively, it is effective in that pits can be formed by a semiconductor laser having a wavelength of about 830 nm. Further, since the organic dye can be formed into a film by wet coating and is easy to handle, it can be easily mass-produced industrially and the equipment cost can be reduced.

The applicant of the present application also discloses, for example,
No. 6879, it is possible to record at a high S / N with a semiconductor laser using a polymethine dye for a recording layer,
An optical recording medium having good thermal stability is disclosed.

The reason why the cost of an optical recording medium can be reduced by using an organic dye for the recording layer is that the organic dye recording layer can be formed by wet coating, as described above. The organic dye used in the recording layer formed by coating must have an absorption maximum near the wavelength of the recording light beam, and have excellent solvent stability in addition to excellent thermal stability. Have been. That is, when an organic dye having insufficient solvent solubility is used, even if a slight change in the concentration of the coating solution causes a solid in the coating solution,
For example, when the recording layer is continuously formed by wet coating as a result of easy precipitation of fine crystals and the like of the organic dye,
This is because solids in the coating solution are mixed into the recording layer, resulting in a low-quality optical recording medium having a high signal noise level during reproduction.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made in view of such circumstances, and it is an object of the present invention to provide excellent stability even under environmental conditions of high wavelength and high temperature and high temperature and high humidity. Provided is an optical recording medium having high recording sensitivity, excellent durability, and capable of reproducing recorded information with high S / N having a recording layer containing an organic dye having further improved solvent solubility. It is in.

Another object of the present invention is to provide a method of manufacturing an optical recording medium having high recording sensitivity, excellent durability, capable of reproducing recorded information at a high S / N, and further excellent productivity. Is to do.

Another object of the present invention is to provide an information recording method capable of reproducing information at a high S / N ratio for a long period of time.

[0012]

That is, an optical recording medium of the present invention comprises a substrate and a recording layer containing a polymethine compound represented by the following general formula (I).

[0013]

[Outside 14] (Where R ₁ and R ₂ represent an aryl group substituted with an alkyl group or an aryl group substituted with an alkoxy group, R ₃ and R ₄ represent a substituted or unsubstituted aryl group,
It represents a substituted or unsubstituted heterocyclic group or a substituted or unsubstituted styryl group. And m is 0, 1 or 2

[0014]

[Outside 15] Represents an anion residue. )

Further, according to the information recording method of the present invention, a recording light beam modulated according to information is irradiated to an optical recording medium having a substrate and a recording layer containing a polymethine compound represented by the following general formula (I). Then, the information is recorded by forming a small concave portion in the recording layer.

[0016]

[Outside 16] (Where R ₁ and R ₂ represent an aryl group substituted with an alkyl group or an aryl group substituted with an alkoxy group, R ₃ and R ₄ represent a substituted or unsubstituted aryl group,
It represents a substituted or unsubstituted heterocyclic group or a substituted or unsubstituted styryl group. And m is 0, 1 or 2

[0017]

[Outside 17] Represents an anion residue. )

Further, the method for producing an optical recording medium of the present invention is directed to a method for producing an optical recording medium comprising a substrate and a recording layer containing a polymethine compound represented by the following general formula (I):
The recording layer is formed by applying a coating solution containing a polymethine compound represented by the following general formula (I) on the substrate.

[0019]

[Outside 18] (Where R ₁ and R ₂ represent an aryl group substituted with an alkyl group or an aryl group substituted with an alkoxy group, R ₃ and R ₄ represent a substituted or unsubstituted aryl group,
It represents a substituted or unsubstituted heterocyclic group or a substituted or unsubstituted styryl group. And m is 0, 1 or 2

[0020]

[Outside 19] Represents an anion residue. )

That is, according to the present invention, the polymethine compound represented by the above general formula (I) exhibits high absorption for light having a wavelength in the near infrared region, has excellent solvent solubility, and has a cyclic voltaic property. Since the oxidation potential in the metrology is high and the oxidation is hardly deteriorated, it is considered that an optical recording medium having high recording sensitivity and excellent durability for a semiconductor laser and capable of reproducing recorded information with high S / N can be obtained.

Hereinafter, the present invention will be described in detail.

The optical recording medium of the present invention is provided with a polymethine compound represented by the following general formula (I) in a recording layer which absorbs electromagnetic radiation for information recording and receives a heat effect to cause an optical change by the heat effect. Is characterized by containing.

[0024]

[Outside 20]

In the general formula (I), R ₁ and R
₂ represents, for example, an aryl group substituted with a substituted or unsubstituted alkyl group represented by the following general formula (II) or an aryl group substituted with a substituted or unsubstituted alkoxy group represented by the following general formula (III).

[0026]

[Outside 21]

[0027]

[Outside 22]

In the above general formula (II), R ₅ represents a substituted or unsubstituted alkyl group. Specifically, examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group and an iso-propyl group. , N-butyl group, sec-butyl group, iso-butyl group, t-butyl group, n-amyl group, t-amyl group, n-hexyl group, n-octyl group,
and a t-octyl group.

Examples of the substituted alkyl group include a 2-hydroxyethyl group, a 3-hydroxypropyl group, a 4-hydroxybutyl group, a 2-acetoxyethyl group, a carboxymethyl group, a 2-carboxyethyl group and a 3-carboxypropyl group. , 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 3-sulfopropyl, 4-sulfobutyl, N- (methylsulfonyl) -carbamylmethyl, 3- (acetylsulfamyl) A) propyl group, 4- (acetylsulfamyl) butyl group and the like, and examples of the cyclic alkyl group include a cyclohexyl group.

When a plurality of alkyl groups are bonded to the aryl group, the alkyl groups may be the same or different.

In the general formula (III), R ₆ represents a substituted or unsubstituted alkoxy group, and specific examples include a methoxy group, an ethoxy group and a propoxy group.

In the above general formulas (II) and (III), R ₅ and R ₆ are each a straight-chain or branched, substituted or unsubstituted lower or lower alkyl group having 1 to 3 carbon atoms. When an alkoxy group is bonded, it is particularly preferably used in the present invention because the solvent solubility is particularly excellent and the environmental stability is also good. Examples of such a lower alkyl group and an alkoxy group include a methyl group, an ethyl group, n
-Propyl group, iso-propyl group and methoxy group, ethoxy group, n-propoxy group, iso-propoxy group and the like.

Next, as R ₃ and R ₄ , substituted or unsubstituted aryl groups (for example, phenyl, naphthyl, tolyl, xylyl, methoxyphenyl, dimethoxyphenyl, trimethoxyphenyl, ethoxyphenyl) Group, dimethylaminophenyl group, diethylaminophenyl group, dipropylaminophenyl group, dibenzylaminophenyl group, diphenylaminophenyl group, ditolylaminophenyl group, dimethoxyaminophenyl group, etc.), substituted or unsubstituted heterocyclic group ( For example, a pyridyl group, a quinolyl group, a lepidyl group, a methylpyridyl group,
A furyl group, a phenyl group, an indolyl group, a pyrrole group, a carbazolyl group, an N-ethylcarbazolyl group, or a substituted or unsubstituted styryl group (for example, a styryl group,
Methoxystyryl group, dimethoxystyryl group, trimethoxystyryl group, ethoxystyryl group, dimethylaminostyryl group, diethylaminostyryl group, dipropylaminostyryl group, dibenzylaminostyryl group, diphenylaminostyryl group, 2,2-diphenylvinyl group ,
2-phenyl-2-methylvinyl group, 2- (dimethylaminophenyl) -2-phenylvinyl group, 2- (diethylaminophenyl) -2-phenylvinyl group, 2- (dibenzylaminophenyl) -2-phenylvinyl Group,
2,2-di (diethylaminophenyl) vinyl group,
2-di (methoxyphenyl) vinyl group, 2,2- (ethoxyphenyl) vinyl group, 2- (dimethylaminophenyl) -2-methylvinyl group, 2- (diethylaminophenyl) -2-ethylvinyl group, etc. .

M represents 0, 1 or 2.

Also,

[0036]

[Outside 23] Are chloride, bromide, iodide, perchlorate, nitrate, benzenesulfonate, p-toluenesulfonate, methylsulfate, ethylsulfate, propylsulfate,
Tetrafluoroborate ion, tetraphenylborate ion, hexafluorophosphate ion, benzenesulfonate ion, acetate ion, trifluoroacetate ion, propion acetate ion, benzoate ion,
Oxalate ion, succinate ion, malonate ion, oleate ion, stearate ion, citrate ion, monohydrogen diphosphate ion, dihydrogen monophosphate ion, pentachlorostannate Salt ion, chlorosulfonate ion, fluorosulfonate ion, trifluoromethanesulfonate ion, hexafluoroarsenate ion, hexafluoroantimonate ion, molybdate ion, tungstate ion, titanate ion And zirconate ions.

Hereinafter, specific examples of the polymethine dye compound used in the present invention are listed below, but the present invention is not limited thereto.

[0038]

[Outside 24]

[0039]

[Outside 25]

[0040]

[Outside 26]

[0041]

[Outside 27]

[0042]

[Outside 28]

[0043]

[Outside 29]

As shown in FIG. 1, the optical recording medium of the present invention
It can be formed by providing a recording layer 2 containing a polymethine dye compound represented by the general formula (I) on a substrate 1.

As the substrate 1, plastics such as polycarbonate, polyester, acrylic resin, polyolefin resin, phenol resin, epoxy resin, polyamide and polyimide, glass and metals can be used.

In forming the recording layer 2, one or a combination of two or more of the polymethine dye compounds represented by the general formula (I) can be used.
For example, polymethine-based, naphtholactam-based, azulene-based, pyrylium-based, squarium-based, croconium-based, triphenylmethane-based, xanthene-based, anthraquinone-based, cyanine-based, phthalocyanine-based, dioxazine-based, and tetrahydrocholine compounds other than the compounds of the formula (I). System, triphenothiazine system, phenanthrene system or metal and metal compound such as Al, Te, Bi, Sn, I
It may be mixed and dispersed or laminated with n, Se, SnO, TeO ₂ , As, Cd, or the like.

These polymethine compounds are, for example,
Bernard S. Widdy (Bernard S. Wi)
ldi) et al. “Journal of American Chemica
Luso Society (J. Am. Chem. Soc.) "8
0,3772-3777 (1958), Etch
H. Schmidf et al.
Nannalendell Chemie (Ann.) "623,204
216 (1959), or Earl Wilzi
Ngar et al.'S "Helvetica Simika Acta (Hel
v. Chimica. Acta) "24,369 (19
41 years).
Can be easily obtained by doing so.

Further, in order to improve the light resistance of the recording layer 2, a stabilizer may be mixed in the recording layer 2. As the stabilizer, various metal chelate compounds, particularly Zn, Cu, N
i, Cr, Co, Mn, Pd, and Zr as central metals, and polydentate ligands such as N ₄ , N ₂ O ₂ , N ₂ S ₂ S ₄ ,
Those having tetradentate ligands such as O ₂ S ₂ and O ₄ or a combination thereof, various aromatic amines, diamines and nitrogen-containing aromatics, and onium salts thereof, for example, aminium salts, diimonium salts, Examples include pyridinium salts, imidazolinium salts, quinolium salts and the like. Further, pyrylium salts and the like, which are oxygen-containing aromatic salts, are also used.

Particularly, an aminium salt represented by the following general formula (IV) or a diimmonium salt represented by the following general formula (V) has good compatibility with the polymethine compound when the recording layer is produced by wet coating. It is possible to obtain a higher-performance optical recording medium having excellent durability and light resistance.

[0050]

[Outside 30] (However, A is

[0051]

[Outside 31] Wherein R _{7 to} R ₁₄ are a substituent having 1 to 8 carbon atoms;
At least one of R _{7 to} R ₁₄ is an alkoxyalkyl group,
An alkenyl group or an alkynyl group,

[0052]

[Outside 32] Represents an anion. )

[0053]

[Outside 33] (However, R _{15 to} R ₂₂ are a substituent having 1 to 8 carbon atoms, and
At least one alkoxyalkyl group ₁₅ to R _22, an alkenyl group or an alkynyl group,

[0054]

[Outside 34] Is an anion. )

The amount of these stabilizers in the recording layer relative to the organic dye as the optical recording material was determined by the weight ratio of the organic dye.

[0056]

[Outside 35] Is preferred.

The recording layer 2 is formed on the substrate 1 by various methods such as a wet coating method or a vapor deposition method such as a vapor deposition method. When the wet coating method is used, it can be formed by applying a solution in which a polymethine compound is dissolved or dispersed in an organic solvent onto the substrate 1. If necessary, a binder can be mixed in the recording layer to form a film, taking into account film forming properties and coating film stability.

The organic solvent that can be used in the wet coating varies depending on whether the above-mentioned polymethine compound is in a dispersed state or a dissolved state, but is generally an alcohol-based, ketone-based, amide-based, ether-based, or ester-based. Solvents, aliphatic halogenated hydrocarbons, aromatics, aliphatic hydrocarbons, fluorines and the like can be used, and solvents having excellent solubility of the polymethine compound of the present invention are particularly preferable.

On the other hand, when the wet application is performed directly on the resin substrate, the organic solvent must be one that does not dissolve the surface of the resin substrate or cause cracks on the surface of the resin substrate. is necessary.

However, since the polymethine compound according to the present invention is excellent in solvent solubility, even when an organic dye is applied by wet coating on a resin substrate, the range of choice of the coating solvent or the material of the substrate is wider than before. At the same time, conditions for producing an excellent optical recording medium having a low noise level can be relaxed as compared with the related art.

Examples of the binder include nitrocellulose, ethyl cellulose, polystyrene, polyvinylpyrrolidone, polymethyl methacrylate, polyamide and the like. Also, if necessary,
Waxes, higher fatty acids, and amides (eg, oleylamide) can be used as additives.

Plasticizers such as dioctyl phthalate, dibutyl phthalate and tricresyl phosphate, oils such as mineral oil and vegetable oil, dispersants such as sodium alkylbenzenesulfonate and polyoxyethylene alkylphenyl ether and other additives are added to the above binders. By appropriately mixing the agents, the film forming property of the recording layer and the stability of the coating film can be improved.

The coating is performed by using a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a Meyer bar coating method, a blade coating method, a curtain coating method, a roller coating method, and a gravure coating method. It can be carried out.

The content of the polymethine compound in the recording layer 2 is 1% or more, usually 40 to 100% by weight, preferably 50 to 100% by weight.
100% by weight is desirable. When the content is 40% by weight or more, it is possible to obtain a sufficient light absorbing property of the recording layer and a sufficient light reflectance with respect to a reproducing laser beam.

The recording layer 2 has a thickness of 100 ° to 20 μm.
m, preferably from 200 ° to 1 μm. In addition,
As long as a thin film having sufficient light reflectivity with respect to the recording laser beam can be formed stably, the thinner the better, the better.

Further, in the optical recording medium of the present invention, as shown in FIG. 2, a protective layer 3 transparent to a recording and reproducing laser beam can be provided on the recording layer 2. The protective layer 3
May be opaque when light is irradiated from the substrate 1 side.

As shown in FIG. 3, an undercoat layer 4 may be provided between the substrate 1 and the recording layer 2. Further, as shown in FIG. 4, both the protective layer 3 and the undercoat layer 4 can be used.

The undercoat layer is composed of (a) an improved adhesiveness, (b) a barrier against water or gas, (c) an improved storage stability of the recording layer, (d) an improved reflectance, and (e) a solvent. And (f) formation of a pre-groove. For the purpose of (a), a polymer material, for example, various materials such as an ionomer resin, a polyamide resin, a vinyl resin, a natural polymer, silicone, a liquid rubber, or various substances such as a silane coupling agent are used. For the purposes (b) and (c), an inorganic compound other than the above-mentioned polymer material, for example, SiO ₂ , MgF
₂ , SiO, TiO ₂ , ZnO, TiN, SiN, etc.
Metal or metalloid, such as Zn, Cu, S, Ni, C
r, Ge, Se, Cd, Ag, Al and the like can be used. For the purpose of (d), metals such as Al, A
g or an organic thin film having a metallic luster, such as a cyanine dye or a methine dye. For the purposes (e) and (f), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the undercoat layer is 50 to 100 μm, preferably 200 μm.
Å-30 μm is appropriate.

The protective layer is provided for the purpose of protecting from scratches, dust, dirt, etc., and improving the storage stability and the reflectance of the recording layer. The same material as that of the undercoat layer is used. can do. The thickness of the protective layer is suitably 100 ° or more, preferably 1000 ° or more.

At this time, the undercoat layer and / or the protective layer may contain the polymethine dye compound of the general formula (I) of the present invention. The undercoat layer or the protective layer may contain a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, and the like.

Further, as another configuration of the optical recording medium according to the present invention, two recording media having the same configuration shown in FIG. 1 to FIG. May be arranged inside and sealed as a so-called air sandwich structure, or may be formed as a so-called close-contact structure (laminated structure) bonded through the protective layer 3.

The optical recording medium (record blank on which no information is recorded) of the present invention thus produced is irradiated with modulated recording electromagnetic radiation to decolor or discolor the recording layer 2. By forming a concave portion (pit), an information record in which information is recorded is obtained.

In particular, the optical recording medium of the present invention is helium-
Recording can also be performed by irradiation with a gas laser such as a neon laser (having an oscillation wavelength of 633 nm), but preferably a laser having a wavelength of 750 nm or more, particularly a gallium-aluminum-arsenic semiconductor laser (having an oscillation wavelength of 830 nm)
The method of forming a concave portion in the recording layer by irradiating a laser beam having an oscillation wavelength in the near infrared or infrared region, such as m), and performing recording is suitable. For reading, the above-mentioned laser beam adjusted to an intensity that does not cause a change in the recording layer can be used. On this occasion,
Writing and reading can be performed with lasers of the same wavelength, and can also be performed with lasers of different wavelengths.

[0074]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

(Synthesis Example 1) The polymethine compound NO. The dye of (5) was synthesized.

4,4'-diaminobenzophenone 4.4
g, 30.9 g of P-iodotoluene, 19.5 g of anhydrous potassium carbonate and 10 g of copper powder were added to 70 ml of O-dichlorobenzene, and the mixture was refluxed at 180 ° C. for 24 hours with stirring. After the reaction, the mixture was filtered and washed with ethyl acetate, and then the mixture was separated by silica gel column chromatography using chloroform to obtain 11.3 g of 4,4'-ditolylaminobenzophenone.

Next, 9 g of 4,4'-ditolylaminobenzophenone was added to 72 ml of tetrahydrofuran in an ether solution of methylmagnesium iodide (2 mol / mol).
l) Reaction with 15.7 g at 60 ° C. for 16 hours.

Next, the reaction mixture is treated with dilute hydrochloric acid and an aqueous solution of sodium hydroxide, filtered, washed with water and recrystallized with ethanol to give 1,1-bis (p-ditolylaminophenyl) -ethylene. 1 g was obtained.

Subsequently, 7 g of 1,1-bis (p-ditolylaminophenyl) -ethylene, 2.5 m of ethyl orthoformate
was dissolved in 25 ml of acetic anhydride, and a mixture of 1.5 ml of perchloric acid and 25 ml of acetic anhydride was added dropwise while cooling with ice, followed by reaction at 90 ° C. for 2 hours. Thereafter, 700 ml of isopropyl ether was added to the reaction solution to cause reprecipitation. Next, the crystals were separated by filtration, washed with isopropyl ether and water, recrystallized from a mixed solvent of acetone and methanol, and dried. 7.2 g of the dye of (5) was obtained.

The compound No. synthesized as described above was used.
(5) had an absorption maximum in the near infrared region at 848.2 nm in acetonitrile. 35% Elemental analysis yield _{(C 85 H 75 N 4 ClO} 4) analysis C: 81.56%, H: 6.02 %, N: 4.4
6% (theoretical value C: 81.54%, H: 6.04%, N: 4.
48%)

Example 1 On a polycarbonate (hereinafter abbreviated as PC) substrate provided with a pregroove by injection molding having a diameter of 130 mm and a thickness of 1.2 mm, the polymethine dye compound No. A solution prepared by dissolving 3 parts by weight of the polymethine dye compound of (1) in 97 parts by weight of diacetone alcohol is applied by a spinner coating method, and then dried and dried.
An organic thin film recording layer of 0 ° was obtained. Further, through a 0.3 mm thick spacer, an ultraviolet ray (UV) curable resin is used.
The two substrates were bonded together to obtain an optical recording medium having an air sandwich structure.

The optical recording medium thus prepared is mounted on a turntable, and the turntable is rotated at 1800 rpm by a motor, and a semiconductor laser having an oscillation wavelength of 830 nm is used. 5 μmφ, recording power 8 mW, recording frequency 3 MH
A pit is formed in the recording layer at z to write information, reproduced at a read power of 0.6 mW, and the reproduced waveform is subjected to spectrum analysis (scanning filter, bandwidth 30 KH).
z) and the C / N ratio was measured.

Next, the same recording medium, the recorded portion in said measurement condition was measured C / N ratio after reading repeated 10 ⁵ times.

Further, the same recording medium produced under the above conditions was left under the conditions of 65 ° C. and 85% RH for 2000 hours, and the transmittance (830) after the environmental storage stability test was performed.
nm measurement) and C / N ratio. Table 1 shows the results.
Shown in

Examples 2 to 5 The polymethine dye compound No. 1 used in Example 1 was used. (1)
Compound No. (3), (4), (14), (29)
Instead, a recording medium was prepared in the same manner as in Example 1,
Optical recording media of Examples 2 to 5 were produced.

The optical recording media of Examples 2 to 5 were measured in the same manner as in Example 1. Table 1 shows the results.

[0087]

[Table 1]

Examples 6 and 7 The following compound Nos. (32) and (33) and the polymethylene dye compound Nos. (5) was mixed with diacetone alcohol at a weight ratio of 1: 2, and applied in the same manner as in Example 1 to provide an organic thin film recording layer having a dry film thickness of 850 °. A recording medium was manufactured.

The optical recording media of Examples 6 and 7 thus produced were measured in the same manner as in Example 1. Table 2 shows the results.

[0090]

[Outside 36]

Comparative Examples 1 and 2 Compound No. 1 used in Example 6 Except for (5),
Optical recording media were produced in the same manner as in Examples 6 and 7, and measurement was performed in the same manner. The results are also shown in Table 2.

[0092]

[Table 2]

Example 8 The above compound No. 2 parts by weight of the compound of (2) and a nitrocellulose resin (Ohales Lacquer, Daicel Chemical Co., Ltd.)
1 part by weight of diacetone alcohol was mixed with 97 parts by weight of diacetone alcohol by a spinner coating method on a PC substrate having a diameter of 130 mm and a thickness of 1.2 mm provided with a pre-groove by injection molding. 1000Å
Was obtained.

The optical recording medium thus prepared was measured in the same manner as in Example 1. Table 3 shows the results.

Example 9 Compound No. 1 used in Example 8 (2) The compound N
o. Instead of (23), an optical recording medium was produced in the same manner as in Example 8, and an optical recording medium of Example 9 was produced.

The optical recording medium of Example 9 was measured in the same manner as in Example 1. Table 3 shows the results.

[0097]

[Table 3]

Example 10 A pregroove was provided on a wallet-sized PC board having a thickness of 0.4 mm by a hot press method, and the polymethine dye compound No. 1 was formed thereon. A solution prepared by mixing 3 parts by weight of the compound of (5) with 97 parts by weight of diacetone alcohol was applied by a bar coating method, and then dried to obtain an organic thin film recording layer of 1000 °. Further, a PC board having a wallet size of 0.3 mm and having a thickness of 0.3 mm was adhered to the substrate via an ethylene-vinyl acetate dry film by a hot roll method to produce an optical card having an adhered structure.

The optical recording medium produced in this manner is mounted on a stage driven in the X and Y directions,
0.4mm thick PC using a 0nm semiconductor laser
A spot size of 3.0 μm is applied to the organic thin film recording layer from the substrate side.
mφ, recording power 3.5 mW, recording pulse 50 μsec
To write information in the Y-axis direction and read power 0.3 m
Playback with W and its contrast ratio

[0100]

[Outside 37] : A = RF signal strength of unrecorded part, B = RF signal strength of recorded part).

Further, the same recording medium produced under the above conditions was subjected to an environmental storage stability test under the same conditions as in Example 1, and the transmittance and contrast ratio thereafter were measured.
Further, the same recording medium produced under the above conditions was subjected to a fade meter light resistance test (10 hours, xenon lamp 1 kW /
m ² ), and the transmittance thereof was measured. Table 4 shows the results.

Example 11 Compound No. 1 used in Example 10 (5) The compound N
o. Instead of (2), a recording medium was produced in the same manner as in Example 10, an optical recording medium in Example 11 was produced, and measurement was carried out in the same manner as in Example 10. Table 4 shows the results.

Comparative Examples 3 and 4 Compound No. 1 used in Example 10 (5) The compound N
o. An optical recording medium was manufactured in the same manner as in Example 10 except that the measurement was changed to (32) and (33), and the measurement was performed in the same manner. Table 4 shows the results.

[0104]

[Table 4]

Example 12 In Example 10, the above-mentioned polymethine dye compound No. In the same manner as in Example 10, except that 2.4 parts by weight of the compound (5) and 0.6 part by weight of the stabilizer represented by the following structural formula (34) were mixed with 97 parts by weight of diacetone alcohol. An optical card was prepared and the initial and initial conditions were set at 65 ° C. and 85% RH in the same manner as in Example 10.
2,000 hours of transmittance, contrast and fade meter light resistance test (100 hours, xenon lamp 1)
kW / m ² ) was measured. Table 5 shows the results.

[0106]

[Outside 38]

[0107]

[Table 5]

Examples 13 and 14 Stripe pregrooves having a width of 3 μm, a pitch of 12 μm and a depth of 3000 mm were formed on a wallet size (85 mm long × 54 mm wide) PC board having a thickness of 0.4 mm by the 2P method. An optical card substrate was prepared.

On the other hand, the organic dye compound No.
(5) and (24) for the polymethine compound 2,
A coating solution for forming a recording layer was prepared using 2,3,3-tetrafluoropropanol as a coating solvent. Next, this coating solution was applied to the surface of the optical card substrate on the side where the pregroove was formed by a roll coater, and a process of forming a recording layer was continuously performed on 100 optical card substrates. Next, a PC protective substrate having a thickness of 0.3 mm was stuck on the recording layer via an ethylene-vinyl acetate copolymer hot melt adhesive sheet to obtain an optical card.

The first and 100th optical cards thus produced were reproduced using an optical card recording / reproducing apparatus (manufactured by Canon Inc.), and their signal waveforms were observed with a spectrum analyzer. 70KH for each optical card
The noise level at z was measured. (Video bandwidth: 1 KHz) The results are shown in Table-6.

Comparative Examples 5 and 6 The same procedures as in Example 14 were carried out except that the following structural formulas (35) and (36) were used instead of the polymethine compound (5) used in Example 14. A card was prepared and evaluated. Table 6 shows the results.

[0112]

[Outside 39]

[0113]

[Table 6]

As can be seen from Table 6 above, Examples 13 and 1 were used.
The noise level of the 100th optical card of the fourth optical card is almost the same as the noise level of the first optical card, whereas the noise level of the 100th optical card of the first and second comparative examples is This indicates that the noise level is significantly higher than the noise level of the optical card.

This is because the solvent solubility of the polymethine dye compound used in Comparative Examples 5 and 6 was not sufficient, and only a small amount of the coating solution occurred when the coating solution was applied to a plurality of substrates in the coating layer forming process. It is considered that even with such a concentration change, a solid substance, for example, fine crystals of a dye compound, easily precipitated in the solution, and was transferred onto the substrate, thereby increasing the noise level.

On the other hand, the polymethine dye compounds of Examples 13 and 14 have high solvent solubility, and crystals are unlikely to be precipitated even by a slight change in the concentration of the coating solution in the coating step. It is considered that an optical card with a low noise level can be obtained without mixing.

[0117]

As described above, according to the present invention, recording is possible with high sensitivity even when a long wavelength oscillation laser such as a semiconductor laser is used. An optical recording medium having an N ratio can be obtained.

Further, according to the present invention, even when the recording layer is formed by wet coating, it is possible to obtain an optical recording medium which always has a low noise level and excellent heat stability.

Further, according to the present invention, high S
An information record capable of reproducing information at a / N ratio can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an embodiment of the optical recording medium of the present invention.

FIG. 2 is a schematic sectional view of another embodiment of the optical recording medium of the present invention.

FIG. 3 is a schematic sectional view of another embodiment of the optical recording medium of the present invention.

FIG. 4 is a schematic sectional view of another embodiment of the optical recording medium of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Recording layer 3 Protective layer 4 Undercoat layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-164594 (JP, A) JP-A-63-207692 (JP, A) JP-A-64-72342 (JP, A) JP-A 64-64 72344 (JP, A) JP-A-1-229694 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/26 G11B 7/24 516

Claims (14)

(57) [Claims] 1. An optical recording medium comprising a substrate and a recording layer containing a polymethine compound represented by the following general formula (I). [Outside 1] (However, R ₁ and R ₂ represent an aryl group substituted with an alkyl group or an aryl group substituted with an alkoxy group, R ₃ and R ₄ represent a substituted or unsubstituted aryl group,
It represents a substituted or unsubstituted heterocyclic group or a substituted or unsubstituted styryl group. M is 0, 1 or 2 Represents an anion residue. ) 2. The optical recording medium according to claim 1, wherein said recording layer is formed by wet coating. 3. In the general formula (I), R ₁ and R ₂
Is an aryl group represented by the following general formula (II), and R ₅
Is a substituted or unsubstituted lower alkyl group having 1 to 3 carbon atoms. [Outside 3] 4. The optical recording medium according to claim 3, wherein in the general formula (II), R ₅ is a methyl group. 5. In the general formula (I), R ₁ and R ₂
Is an aryl group represented by the following general formula (III),
_2. The optical recording medium according to claim 1, wherein ₆ is a substituted or unsubstituted lower alkoxy group having 1 to 3 carbon atoms. [Outside 4] 6. The optical recording medium according to claim 5, wherein in the general formula (III), R ₆ is a methoxy group. 7. The optical recording medium according to claim 1, wherein the recording layer contains a stabilizer. 8. The optical recording medium according to claim 7, comprising at least one of the compounds represented by the following general formulas (IV) and (V) as said stabilizer. [Outside 5] (However, A is [outside 6] Wherein R _{7 to} R ₁₄ are a substituent having 1 to 8 carbon atoms;
At least one of R _{7 to} R ₁₄ is an alkoxyalkyl group,
An alkenyl group or an alkynyl group, Represents an anion. [Outside 8] (However, R _{15 to} R ₂₂ are a substituent having 1 to 8 carbon atoms, and
At least one of ₁₅ to R ₂₂ is an alkoxyalkyl group, an alkenyl group or an alkynyl group, circumflex 9] Is an anion. ) 9. The optical recording medium according to claim 1, wherein said optical recording medium is a record blank. 10. The optical recording medium according to claim 1, wherein the optical recording medium is an information record in which information is recorded by forming pits by irradiating a recording light beam onto the recording layer. 11. The optical recording medium according to claim 1, further comprising an undercoat layer between said substrate and said recording layer. 12. The recording medium according to claim 1, further comprising a protective layer on the recording layer.
Optical recording medium. 13. An optical recording medium comprising a substrate and a recording layer containing a polymethine compound represented by the following general formula (I) is irradiated with a recording light beam modulated according to information,
An information recording method, wherein a small concave portion is formed in the recording layer to record the information. [Outside 10] (Where R ₁ and R ₂ represent an aryl group substituted with an alkyl group or an aryl group substituted with an alkoxy group, R ₃ and R ₄ represent a substituted or unsubstituted aryl group,
It represents a substituted or unsubstituted heterocyclic group or a substituted or unsubstituted styryl group. M is 0, 1 or 2 Represents an anion residue. ) 14. A method for producing an optical recording medium comprising a substrate and a recording layer containing a polymethine compound represented by the following general formula (I), comprising a polymethine compound represented by the following general formula (I): A method for producing an optical recording medium, comprising applying a coating liquid onto the substrate to form the recording layer. [Outside 12] (Where R ₁ and R ₂ represent an aryl group substituted with an alkyl group or an aryl group substituted with an alkoxy group, R ₃ and R ₄ represent a substituted or unsubstituted aryl group,
It represents a substituted or unsubstituted heterocyclic group or a substituted or unsubstituted styryl group. And m is 0, 1 or 2. Represents an anion residue. )