JPH0813572B2 - Optical recording medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical recording medium suitable for writing and recording by laser light, particularly semiconductor laser light, and more specifically, an optical recording medium that can be used in optical disk or optical card technology. It is about.

[Conventional technology]

In general, an optical disc and an optical card are provided with a thin recording layer on a substrate, and a small (for example, about 1 μ) optically detectable pit (recess) is formed in the recording layer in a spiral, circular or linear track form. By providing the high density information, high density information can be stored.

To write information on such a disc or card, laser light focused on the surface of the recording layer is scanned, and pits are formed only on the surface irradiated with this laser light. It is necessary to form it in the form of a straight track.

The recording layer can form pits that can absorb laser energy and be optically detectable.

For example, in the heat mode recording method, the recording layer absorbs thermal energy, and small pits can be formed at that location by evaporation or melting. It is possible to form pits having a density difference that can be detected visually.

The structure recorded on the optical disk and the optical card is detected by scanning the laser beam along the track and reading the optical change in the portion where the pit is formed and the portion where the pit is not formed.

In the case of an optical disc, for example, laser light is scanned along a track and the light energy reflected from the disc is monitored by a photodetector. The laser light is sufficiently reflected in the portion where the pits are not formed, and the output of the photodetector is large, whereas the reflection is low in the portion where the pitch is formed, and the output of the photodetector is small.

As recording media used for such optical discs and optical cards, metal thin films such as Te and Bi, or inorganic substance thin films such as chalcogenite amorphous thin films have been mainly proposed. Since it has a high reflectance with respect to, the utilization rate of the laser light is low, and it has the drawbacks that it is weak against oxidation and humidity.

On the other hand, in recent years, research has been conducted on organic thin films capable of changing optical properties by light energy.

Such an organic thin film can be easily selected according to the oscillation wavelength of laser light, and in particular, organic compounds having absorption characteristics for light energy of a relatively long wavelength (for example, 780 nm or more) have been investigated. In addition, recently, due to the shortening of the wavelength of semiconductor lasers and the use of SHG (second harmonic generation) elements to output half the wavelength of laser light, the output wavelength has changed from the visible to the ultraviolet region. Lasers have been developed.

However, organic compounds that can easily cope with such technological trends are unstable to heat and light,
Moreover, since there are technical problems in terms of sublimation,
At present, it cannot necessarily be said that organic thin films that are satisfactory in terms of characteristics have been developed.

[Problems to be solved by the invention]

An object of the present invention is to provide an optical recording medium having an organic thin film having large absorption and reflection characteristics at the oscillation wavelength of laser light, and particularly having an absorption band on the long wavelength side.

Another object of the present invention is to provide an optical recording medium having an organic thin film that is stable to heat and light.

[Means and Actions for Solving Problems]

The present invention provides an optical recording medium having a recording layer on a substrate, the recording layer containing one or more diazulenium salt compounds represented by the following general formula [I], [II] or [III]. It is characterized by being an organic thin film.

In the general formulas [I], [II] and [III], R _{1 to} R ₇
And R ₁ ′ to R ₇ ′ represent a hydrogen atom, a halogen atom (chlorine atom, bromine atom, iodine atom) or a monovalent organic residue. The monovalent organic residue can be selected from a wide range, but particularly alkyl groups (methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-amyl, n-hexyl). , N-octyl, 2-
Ethylhexyl, t-octyl, etc.), alkoxy groups (methoxy, ethoxy, propoxy, butoxy, etc.),
A substituted or unsubstituted aryl group (phenyl, tolyl,
Xylyl, ethylphenyl, methoxyphenyl, ethoxyphenyl, chlorophenyl, nitrophenyl, dimethylaminophenyl, α-naphthyl, β-naphthyl, etc.), substituted or unsubstituted aralkyl (benzyl, 2
-Phenylethyl, 2-phenyl-1-methylethyl,
Bromobenzyl, 2-bromophenylethyl, methylbenzyl, methoxybenzyl, nitrobenzyl), acyl group (acetyl, propionyl, butyryl, valeryl, benzoyl, trioyl, naphthoyl, phthaloyl, furoyl, etc.), substituted or unsubstituted amino group ( Amino, dimethylamino, diethylamino, dipropylamino, acetylamino, benzoylamino, etc.) and substituted or unsubstituted styryl groups (styryl, dimethylaminostyryl, diethylaminostyryl, dipropylaminostyryl, methoxystyryl, ethoxystyryl, methylstyryl, etc.) , Nitro group, hydroxy group, carboxyl group, cyano group or substituted or unsubstituted arylazo group (phenylazo, α-naphthylazo, β-naphthylazo, dimethylaminophenyl) Azo, chlorophenylazo, nitrophenylazo, methoxyphenylazo, tolylazo and the like).

 Also, R₁And R₂, R₂And R₃, R₃And R_Four, R_FourAnd R_Five, R
_FiveAnd R₆, R₆And R₇And R₁'And R₂′, R₂'And R₃′,
R₃'And R_Four′, R_Four'And R_Five′, R_Five'And R₆′, R₆'When
R₇Replace with at least one of the '
Alternatively, an unsubstituted fused ring may be formed. As a condensed ring
A 5-, 6-, or 7-membered condensed ring containing an aromatic ring
Benzene, naphthalene, chlorobenzene, bromobenze
Amine, methylbenzene, ethylbenzene, methoxybenze
Amine, ethoxybenzene, etc.), heterocycle (furan ring, benzene)
Zofuran ring, pyrrole ring, thiophene ring, pyridine ring,
Quinoline ring, thiazole ring, etc.), aliphatic ring (dimethyi ring)
Len, trimethylene, tetonamethylene, etc.)
You. Z Represents an anion residue.

R _{1 to} R ₇ and R ₁ ′ to R ₇ ′ may be the same or different.

 A represents a monovalent organic residue. Zia containing such A
Specific examples of the zurenium salt compound include the following general formula (1)
The following can be mentioned: However
Q in the formula Represents the following diazulenium salt nucleus and has the formula
Q inside The right side except for indicates A.

Diazulenium salt nucleus (Q )  Where R₁~ R₇And R₁'~ R₇'Is defined above
It has the same definition as

In the formula, R _{1 to} R ₇ and R ₁ ′ to R ₇ ′ have the same definition as defined above.

In the formula, R ₁ ″ to R ₇ ″ have the same definitions as R _{1 to} R ₇ defined above.

 Z Represents an anion residue, for example, chloride ion, odor
Iodide ion, iodide ion, perchlorate ion, nitric acid
Salt ion, benzenesulfonate ion, P-toluene
Sulfonate ion, methyl sulfate ion, ethyl sulfate
Salt ion, propyl sulfate ion, tetrafluoroboro
Salt ion, tetraphenyl borate ion, hexaf
Luorophosphate ion, benzenesulfinate ion,
Acetate ion, trifluoroacetate ion, propion
Acetate ion, benzoate ion, oxalate ion,
Succinate, malonate, oleate
On, stearate ion, citrate ion, mono water
Elemental diphosphate ion, dihydrogen-phosphate ion, penta
Chlorostannate ion, chlorosulfonate ion,
Luorosulfonate ion, trifluoromethanesulfone
Phosphate ion, hexafluoroarsenate ion, hexaf
Luoroantimonate ion, molybdate ion,
Tungstate ion, titanate ion, zircon
Represents an anion such as a salt ion.

R ₈ and R ₉ are hydrogen atom, halogen atom, nitro group,
It represents a cyano group, an alkyl group (methyl, ethyl, propyl, butyl, etc.) or an aryl group (phenyl, tolyl, xylyl, etc.), and n represents 0, 1 or 2.

 R in the formula₁~ R₇And R₁'~ R₇'Is also defined above
Has the same definition as, and Q Diazirhenium
What is the salt nucleus and the diazulene salt nucleus on the right side of the general formula (4)?
It may be symmetrical or asymmetrical.

 R₈, R₉And Z Is the same definition as defined above
And n represents 0, 1 or 2.

 R in the formula₁~ R₇, R₁'~ R₇′, R₁″ 〜R₇″, And Z
Has the same definition as defined above. Also Q
Of the azurenium salt nucleus shown on the right side of the general formula (6)
May or may not be symmetrical with the diazulene salt nucleus
There may be.

 R in the formula₁~ R₇, R₁'~ R₇′, R₈And Z Is the same as above
Has the same definition as was meant. Also Q As shown by
Rhenium salt nuclei and siazulene on the right side of general formula (7)
It may be symmetrical or asymmetrical to the salt nucleus
Yes.

A is a divalent hydrocarbon group forming a 5-membered or 6-membered ring substituted or unsubstituted (for example _{-CH 2 -CH 2 -, - CH} 2 -CH 2
-CH ₂ , -CH = CH-, etc.) and may be condensed with a 5- or 6-membered benzene ring, naphthalene ring or the like. n and m represent 1, 2 or 3.

 X in the general formulas (8) and (9)₁Is pyridine, thiazo
, Benzothiazole, naphthothiazole, oxazo
, Benzoxazole, naphthoxazole, imimi
Dazole, benzimidazole, naphthimidazole,
2-quinoline, 4-quinoline, isoquinoline or India
Non-metal atom necessary to complete a nitrogen-containing heterocycle such as
Representing a group, such heterocycles include halogen atoms (chlorine
Child, bromine atom, iodine atom), alkyl group (methyl, ethyl)
Group, propyl, butyl, etc.), aryl groups (phenyl,
Even if it is substituted with (tril, xylyl, etc.)
Good. R_TenIs an alkyl group (methyl, ethyl, propyl,
Butyl, etc.), substituted alkyl groups (2-hydroxyethyl)
2-methoxyethyl, 2-ethoxyethyl, 3-hi
Droxypropyl, 3-methoxypropyl, 3-etoki
Cypropyl, 3-chloropropyl, 3-promopropyi
, 3-carboxypropyl, etc.), cyclic alkyl groups
(Cyclohexyl, cyclopropyl), allyl, aral
Kill group (benzyl, 2-phenylethyl, 3-phenyl)
Propyl, 4-phenylbutyl, α-naphthylmethyl,
β-naphthylmethyl), substituted aralkyl groups (methylben
Zil, ethylbenzyl, dimethylbenzyl, trimethyl
Benzyl, chlorobenzyl, promobenzyl, etc.)
Reel group (phenyl, tolyl, xylyl, α-naphthyl
Or β-naphthyl) or a substituted aryl group (chlorophenyl)
Le, dichlorophenyl, trichlorophenyl, ethyl
Phenyl, methoxyphenyl, dimethoxyphenyl, ami
Nophenyl, nitrophenyl, hydroxyphenyl
Represents). m represents 0, 1 or 2 and R₈, R₉, R₁₁,
And Z Has the same definition as defined above
You.

 R in the formula_TenIs a substituted or unsubstituted aryl group (phenyl,
Trilyl, xylyl, biphenyl, α-naphthyl, β-na
Futyl, anthralyl, pyrenyl, methoxyphenyl,
Dimethoxyphenyl, trimethoxyphenyl, ethoxy
Phenyl, diethoxyphenyl, chlorophenyl, dich
Lorophenyl, trichlorophenyl, bromophenyl,
Dibromophenyl, tribromophenyl, ethylphenyl
L, diethylphenyl, nitrophenyl, aminophenyl
L, dimethylaminophenyl, diethylaminophenyl
Le, dibenzylaminophenyl, dipropylaminophenyl
Nil, morpholinophenyl, piperidinyl phenyl,
Perazinophenyl, diphenylaminophenylacetyl
Aminophenyl, benzoylaminophenyl, acetyl
(Phenyl, benzoylphenyl, cyanophenyl, etc.)
Represents Z Has the same definition as defined above
I do. Further, m represents 0, 1 or 2.

 Where R₁₃Is furan, thiophene, benzofuran,
Onaphthene, dibenzofuran, carbazole, phenothi
Derived from heterocycles such as azine, phenoxazine and pyridine
Represents a derived monovalent heterocyclic group, Is defined above
Has the same definition as In addition, m is 1 or 2
Represent.

 Where R₁₄Is an alkyl group (methyl, ethyl, propyl
Or butyl) or a substituted or unsubstituted aryl group
(Phenyl, tolyl, xylyl, biphenyl, ethyl
Phenyl, chlorophenyl, methoxyphenyl, ethoxy
Phenyl, nitrophenyl, aminophenyl, dimethyl
Aminophenyl, diethylaminophenyl, acetyl
Minophenyl, α-naphthyl, β-naphthyl, anthra
Lil, birenyl, etc.). R₁₂And Z Is before
It has the same definition as defined above. m is 1 or
Represents 2.

 Where X₂Is an optionally substituted pyran, thiapyran,
Serenapyran, Benzopyran, Benzothiapyran, Ben
Zoselenapyran, naphthopyran, naphthopyran or
The atomic groups necessary to complete naphthoselenapyran are shown below.
l is 0 or 1. Y is a sulfur atom, an oxygen atom or
Represents a selenium atom. R₁₄And R_FifteenIs a hydrogen atom (
(Cyl, ethyl, propyl, butyl, etc.), alkoxy groups
(Methoxy, ethoxy, propoxy, butoxy, etc.),
A substituted or unsubstituted aryl group (phenyl, tolyl,
Xylyl, chlorophenyl, biphenyl, methoxyphenyl
Nil), a substituted or unsubstituted styryl group (styryl)
, P-methylstyryl, o-chlorostyryl, p-meth
Substituted or unsubstituted 4-phenol, etc.
Nyl 1,3-butadienyl group (4-phenyl 1,3-bu
Tadiniel, 4- (p-methylphenyl) -1,3-bu
Tadienyl, etc.) or substituted or unsubstituted heterocyclic group
(Quinolyl, pyridyl, carbazolyl, furyl, etc.)
Represent. Also R₈, R₉, m and Z Is also defined above
Has the same definition as

Specific examples of the diazulenium salt compound used in the present invention are listed below.

Examples of compounds represented by the general formula (1) Compound No. Examples of compounds represented by the general formula (2) Examples of compounds represented by the general formula (3) Examples of compounds represented by the general formula (4) Examples of compounds represented by the general formula (5) Examples of compounds represented by the general formula (6) Examples of compounds represented by the general formula (7) Examples of compounds represented by the general formulas (8) and (9) Examples of compounds represented by the general formula (10) Examples of compounds represented by the general formula (11) Examples of compounds represented by the general formula (12) Examples of compounds represented by the general formula (13) Next, the synthetic method of the diazurhenium compound used in the present invention will be described. The compounds represented by the general formulas (1) and (2) are obtained by reacting a 1,1-azulenylmethane compound with squalic acid or croconic acid in a suitable solvent. It can be easily obtained. The compounds represented by the general formula (3) include 1,1-azurenylmethane compounds, 1-formylazulene compounds and 3-azulene-1'-
Profenaldehyde compound or 3-azulene-1 '
-Pentadiene aldehyde compound in the presence of a strong acid in a suitable solvent. The compound represented by the general formula (4) is prepared by mixing a 1,1-azurenylmethane compound and orthoacetals, orthoesters, malondialdehydes or glutacondialdehydes in the presence of a strong acid in a suitable solvent. Obtained by The compound represented by the general formula (5) can be obtained by heating a 1,1-azurenylmethane compound and glyoxal in the presence of a strong acid in a suitable solvent. The compound represented by the general formula (6) is, in the presence of a strong acid, 1,
It is obtained by heating a 1-bis- [1-azurenyl] -ethane compound and a 1,3-diformylazulene compound in a suitable solvent. The compound represented by the general formula (7) can be obtained by reacting a 1,1-azurenylmethane compound with cyclopentanes or cyclohexanes in the presence of a strong acid in a suitable solvent. For the compound represented by the general formula (8), when m = 1 or 2, 1,1-bis [1-azurenyl] -ethane and the compound represented by the following general formula (14) are suitable in the presence of a strong acid. It is obtained by reacting in a different solvent.

In the formula, X ₁ , R ₈ , R ₉ , R ₁₀ and m, n have the same definitions as defined above. When m = 0, it can be obtained by reacting the compound represented by the following general formula (15) with the compound represented by the following general formula (16) using a suitable solvent.

In the formula, R _{1 to} R ₇ and R ₁ ′ to R ₇ ′ have the same definition as defined above.

 Where X₁, R_Ten, Z , And n are as defined above
Has the same definition as

When m = 1 or 2, when the compound represented by the general formula (9) is 1,1-bis [1-azurenyl] -ethane and the compound represented by the following general formula (17) are suitable in the presence of a strong acid. Obtained by reacting in a solvent.

In the formula, X ₁ , A, R ₈ , R ₉ , R ₁₀ , R ₁₁ and m, n have the same definitions as defined above. When m = 0, the compound represented by the general formula (15) and the following general formula (18)
It can be obtained by reacting a compound represented by: in a suitable solvent.

 Where X₁, A, R_Ten, R₁₁, Z And n are defined above
It has the same definition as

As the compound represented by the general formula (10), (11) or (12), 1,1-azurenylmethane or 1,1-bis [1-azurenyl] -ethane and a corresponding aldehyde compound are suitably used in the presence of a strong acid. It is obtained by mixing in various solvents.

The compound represented by the general formula (13) has m = 1 or 2
In the case of 1, it is obtained by reacting 1,1-bis [1-azurenyl] -ethane with a compound represented by the following general formula (19) in the presence of a strong acid in a suitable solvent.

In the formula, X ₂ , Y, R ₈ , R ₉ , R ₁₄ , R ₁₅ , m and 1 have the same definitions as defined above. When m = 0,
The compound represented by the general formula (15) and the following general formula (2
It is obtained by reacting the compound represented by 0) in a suitable solvent.

 Where X₂, Z , R₁₄, R_FifteenAnd l are also defined above
Has the same definition as

Examples of the reaction solvent used include alcohols such as ethanol, butanol and benzyl alcohol, nitriles such as acetonitrile and propionitrile, organic carboxylic acids such as acetic acid, acid anhydrides such as acetic anhydride, dioxane and alicyclic rings such as tetrahydrofuran. Formula ethers and the like are used. It is also possible to mix butanol, benzyl alcohol, etc. with an aromatic hydrocarbon such as benzene. The temperature during the reaction can be selected from the range of 0 ° C to the boiling point.

The optical recording medium of the present invention can have a structure as shown in FIG. 1, for example. The optical recording medium shown in the figure has the above-mentioned general formula [I], [II] or [II] on the substrate 1.
It can be formed by providing the recording layer 2 which is an organic thin film containing the compound represented by the formula [I]. Recording layer 2
Can be formed by vacuum-depositing the compound represented by the above general formula [I], [II] or [III], or by applying a coating liquid dissolved or dispersed in an organic solvent. it can.

Further, in forming the recording layer 2, the general formula [I],
Two or more compounds represented by [II] or [III] can be used in combination, and further other dyes, for example, diazulene compounds other than the compounds of the above general formulas [I], [II] or [III], Examples of azulene, polymethine, pyrylium, squarylium, croconium, triphenylmethane, xanthene, anthraquinone, cyanine, phthalocyanine, dioxazine, tetrahydrocholine, triphenothiazine, phenanthrene,
Metal chelate complex dyes, etc., or metals and metal compounds, such as Al, Te, Bi, Sn, In, Se, SnO, TeO ₂ , As,
It may be mixed and dispersed or laminated with Cd or the like.

Further, the compound of the general formula [I], [II] or [III] may be contained in the binder in a dispersed state or a dissolved state. For example, nitrocellulose, cellulose phosphate, cellulose sulfate, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose myristate, cellulose palmitate, cellulose acetate / propionate, cellulose esters such as cellulose acetate / butyrate, methyl cellulose, ethyl cellulose, Propyl cellulose, butyl cellulose, and other cellulose ethers, polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal,
Polyvinyl alcohol, polyvinyl resins such as polyvinylpyrrolidone, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, copolymer resins such as vinyl chloride-vinyl acetate copolymer, polymethyl methacrylate, polymethyl acrylate, poly Acrylic resins such as butyl acrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyacrylonitrile, polyesters such as polyethylene terephthalate, poly (4,4'-isopropylidene diphenylene-co-1,4-cyclohexyl) (Range methylene carbonate),
Poly (ethylenedioxy-3,3'-phenylene thiocarbonate), poly (4,4'-isopropylidene diphenylene carbonate-co-terephthalate), poly (4,4
4'-isopropylidene diphenylene carbonate),
Polyarylate resins such as poly (4,4'-sec-butylidene diphenylene carbonate) and poly (4,4'-isopropylidene diphenylene carbonate-block-oxyethylene), or polyamides, polyimides, epoxies Resins, phenolic resins, polyolefins such as polyethylene, polypropylene and chlorinated polyethylene can be used.

Further, the recording layer 2 may contain a surfactant, an antistatic agent, a stabilizer, a dispersant, a flame retardant, a lubricant, a plasticizer and the like.

The organic solvent that can be used during coating varies depending on whether it is in a dispersed state or in a dissolved state, but generally, alcohols such as methanol, ethanol, isopropanol, diacetone alcohol, acetone, methyl ethyl ketone, cyclohexanone, etc. Ketones, N,
N-dimethylformamide, N, N-dimethylacetamide and other amides, dimethyl sulfoxide and other sulfoxides, tetrahydrofuran, dioxane, ethylene glycol monomethyl ether and other ethers, methyl acetate, ethyl acetate, butyl acetate and other esters, chloroform , Methylene chloride, dichloroethylene, carbon tetrachloride, trichloroethylene and other aliphatic halogenated hydrocarbons, benzene, toluene, xylene, monochlorobenzene, dichlorobenzene and other aromatic compounds, or n-
Aliphatic hydrocarbons such as hexane, cyclohexane, and ligroin can be used.

The coating can be performed 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 roller coating method, and a curtain coating method.

The recording layer 2 has a dry film thickness or vapor deposition film thickness of 50Å to 100μ.
m is preferably 200Å to 1 μm.

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

Further, the present invention can also be configured to have an undercoat layer and 1 or a protective layer 4, as shown in FIGS. 2 to 4.

The undercoat layer has (a) improved adhesion, (b) water or gas barrier, (c) improved storage stability of the recording layer,
It is provided for the purpose of (d) improving the reflectance, (e) protecting the substrate from a solvent, and (f) forming a pre-group. For the purpose of (a), a polymer material such as an ionomer resin, an amide resin, a vinyl resin, a natural polymer,
Various materials such as silicone and liquid rubber or various substances such as silane coupling agent can be used,
For the purposes of (b) and (c), in addition to the above polymeric materials, inorganic compounds such as SiO ₂ , MgF ₂ , SiO, TiO ₂ , ZnO, TiN, S
Metals or semi-metals such as iN such as Zn, Cu, S, Ni, Cr,
Ge, Se, Cd, Ag, Al, etc. can be used. (D)
For the purpose of, a metal such as Al, Ag or the like or an organic thin film having a metallic luster such as diazulene dye, methine dye or the like can be used, and for the purposes of (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 50Å-10
0 μm, preferably 200 to 30 μm is suitable. The protective layer is provided for the purpose of protecting it from scratches, dust, dirt, etc., and improving the storage stability and reflectance of the recording layer. As the material thereof, the same material as that of the undercoat layer can be used. . The thickness of the protective layer is 50Å, preferably 30 μm
The above is appropriate. At this time, the above-mentioned general formula [I] [II] or [II] of the present invention is contained in the undercoat layer and / or the protective layer.
The compound of I] may be contained. Further, 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 constitution of the optical recording medium according to the present invention, two recording mediums of the same constitution shown in FIGS. 1 to 4 (in some cases, one of them is used only as a substrate) are used as an organic thin film. A so-called air sandwich structure in which a certain recording layer 2 is disposed inside and sealed may be used, or a so-called close contact structure (bonding structure) in which the protective layer 4 is bonded and bonded.

The optical recording medium of the present invention includes an argon laser (oscillation wavelength 488 nm), a helium-neon laser (oscillation wavelength 633n).
It is also possible to record by irradiation with a gas laser such as m) or a helium-cadmium laser (oscillation wavelength 442 nm).

Recording can also be performed by irradiation with light having a wavelength half the laser light using an SHG element or the like, but preferably a laser having a wavelength of 650 nm or more, particularly a gallium-aluminum-arsenic semiconductor laser (oscillation wavelength 830 nm) A method of recording by irradiating a laser beam having an oscillation wavelength in a certain infrared region such as near infrared is suitable. Further, the laser beam described above can be used for reading. On this occasion,
Writing and reading can be performed with lasers of the same wavelength, or with lasers of different wavelengths.

Hereinafter, the present invention will be described in detail according to examples, but the invention is not limited thereto.

Example 1 On a polymethylmethacrylate (hereinafter abbreviated as "PMMA") substrate having a diameter of 130 mmφ and a thickness of 1.2 mm, an epoxy-acrylate-based UV curable resin was used to perform a 2P method (photopolymer method) and a thickness of 50 μm. A groove was provided, and a solution prepared by dissolving 2 parts by weight of the compound No. (17) in 98 parts by weight of dichloroethane was applied on the groove by a spinner coating method, and then dried to obtain an 800 Å organic thin film recording layer.

The optical recording medium thus prepared was mounted on a turntable, the turntable was rotated by a motor to 1800 rpm, and a semiconductor laser with an oscillation wavelength of 830 nm was used to form a spot size of 1.5 μmφ on the organic thin film recording layer from the substrate side.
Information was written at a recording power of 6 mW and a recording frequency of 2 HMz, reproduced at a read power of 0.8 mW, and the reproduced waveform was subjected to spectrum analysis (scanning filter bandwidth 30 kHz) to measure the C / N ratio (carrier / noise ratio).

Next, the C / N ratio was measured after the portion of the same recording medium recorded under the above measurement conditions was repeatedly read 10 ⁵ times.

Further, the same recording medium produced under the above conditions was 60 ° C.
Transmittance (T (%): 830 nm measurement) and C / after carrying out environmental preservation stability test by leaving it for 2000 hours under the condition of 95% RH
The N ratio was measured. In addition, 1000 W / m ² (300
(About 900 nm) was irradiated for 70 hours with a xenon lamp, and a light resistance stability test was performed, and then the transmittance (T (%): 830 nm measurement) and the C / N ratio were measured. The results are shown in Table-1.

Examples 2 to 15 Compounds No. (17) used in Example 1 were replaced with the respective compounds shown in Table 2 to prepare recording media in the same manner as in Example 1, and the recording media of Examples 2 to 15 were prepared. An optical recording medium was produced.

The optical recording media of Examples 2 to 15 were measured in the same manner as in Example 1, and the results are shown in Table 2.

Examples 16 and 17 The following compound Nos. (73) and (74) and the compound No.
(17) and (17) were mixed with dichloroethane in a weight ratio of 1: 1 and coated in the same manner as in Example 1 to give a dry film thickness of 750Å
The recording layer, which is an organic thin film of
The optical recording medium of was produced. Example thus prepared
The optical recording media 16 and 17 were measured in the same manner as in Example 1, and the results are shown in Table 3.

Comparative Example 1 An optical recording medium was prepared and measured in the same manner as in Example 16 except that the compound No. (17) used in Example 17 was omitted. The results are shown in Table-3.

Example 18 2 parts by weight of the compound No. (2) and 1 part by weight of nitrocellulose resin (Ohaless lacquer, manufactured by Daicel Chemical Industries, Ltd.) were mixed with 97 parts by weight of methyl ethyl ketone to prepare a pregroup by a spinner coating method. Provided diameter 130 mmφ
It was applied on a 1.2 mm thick PMMA substrate to obtain an organic thin film recording layer having a dry film thickness of 1000 liters.

The optical recording medium thus manufactured was measured in the same manner as in Example 1, and the results are shown in Table 4.

Examples 19 to 25 Compound No. (2) used in Example 18 was replaced with the above compound No.
(16), (26), (31) (36), (44), (53), (6
Instead of 6), recording media were prepared in the same manner as in Example 18, and optical recording media of Examples 19 to 25 were prepared.

The optical recording media of Examples 19 to 25 were measured in the same manner as in Example 18, and the results are shown in Table 4.

Examples 26 and 27 Compounds of the above compounds No. (1) and No. (22) 500 m
After putting g into a molybdenum board for vapor deposition and evacuating to 1 × 10 ^-6 mmHg or less, a diameter of 130 mmφ with a pre-groove
It was vapor-deposited on a 1.2 mm PMMA substrate. During vapor deposition, a 950 Å organic thin film recording layer was formed while controlling the heater so that the pressure in the vacuum chamber did not rise above 10 ^-5 mmHg.
Twenty-seven optical recording media were made.

The optical recording medium thus manufactured was measured in the same manner as in Example 1, and the results are shown in Table-5.

Example 28 A wallet-sized 0.4 mm polycarbonate (hereinafter abbreviated as “PC”) substrate was provided with a pregroup by a hot pressing method, and the compound No. (26) was added thereto with 96 parts by weight of diacetone alcohol. The solution mixed with was applied by a bar coat method and then dried to obtain a 900 Å organic thin film recording layer. Further, an optical recording medium of Example 28 having a close contact structure was prepared by a hot roll method and a wallet-sized PC substrate having a thickness of 0.3 mm with an ethylene-vinyl acetate dry film interposed therebetween.

The optical recording medium of Example 28 thus prepared was used as XY
Mounted on stage driven in the direction, oscillation wavelength 830nm
With a semiconductor laser of 0.4 mm, a spot size of 30 μmφ and recording power of 4.0 m on the organic thin film recording layer from the PC substrate side of 0.4 mm thickness
Information is written in the Y-axis direction with W and a recording pulse of 80 μsec and reproduced with a read power of 0.4 mW, and the contrast ratio Furthermore, the same recording medium produced under the above conditions was used in Example 1.
An environmental storage stability test and a light stability test were performed under the same conditions as above, and then the transmittance and the contrast ratio were measured. The results are shown in Table-6.

As described above, the optical recording medium of the present invention can obtain the following remarkable effects.

(1) It has a large absorption and reflection characteristic at the oscillation wavelength of the laser light, and in particular, high recording and reproduction characteristics can be obtained by using a long wavelength oscillation laser of a semiconductor laser.

(2) A good pit shape can be formed and a high C / N ratio can be obtained.

(3) A recording medium having high stability to heat and light, excellent storage stability, and little deterioration in reproduction can be obtained.

[Brief description of drawings]

1 to 4 are sectional views showing the structure of the optical recording medium of the present invention. 1 ... Substrate, 2 ... Recording layer, 3 ... Undercoat layer, 4 ... Protective layer.

Continuation of front page (56) Reference JP 62-140887 (JP, A) JP 62-140888 (JP, A) JP 62-141537 (JP, A) JP 62-141654 (JP , A) JP 62-142688 (JP, A) JP 63-312186 (JP, A)

Claims (1)

[Claims] 1. An optical recording medium having a recording layer provided on a substrate.
The recording layer has the following general formulas [I], [II]
Is one of the diazulenium salt compounds represented by [III]
Or an organic thin film containing two or more kinds
Optical recording medium. (However, in general formulas [I], [II] and [III],
And R₁~ R₇And R₁'~ R₇′ Is a hydrogen atom, halogen
Represents an atom or a monovalent organic residue, or R₁When
R₂, R₂And R₃, R₃And R_Four, R_FourAnd R_Five, R_FiveAnd R₆, R₆When
R₇, R₁'And R₂′, R₂'And R₃′, R₃'And R_Four′,
R_Four'And R_Five′, R_Five'And R₆'And R₆'And R₇′ Set
Replace with at least one of the combinations
May form an unsubstituted fused ring. A is a monovalent organic residue
Represents a group, Z Represents an anion residue. )