JP2002002110A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic coloring matter-based optical recording medium, on which the recording and reproduction by laser beams having short wavelengths of 350 to 530 nm is possible. SOLUTION: In the optical recording medium, in which a recording layer recordable and reproducible with laser is provided on a substrate, the recording layer includes a coloring matter represented by general formula (D), wherein rings A and A' represent aromatic hydrocarbon rings, aromatic heterocycles, sandwich molecules or semi-sandwich molecules under the state that one and the other rings may well be substituted equally to or differently from each other. A benzene ring B further may well have a substituent.

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 using an organic dye for a recording layer, and more particularly to a write-once optical recording medium compatible with a blue laser.

[0002]

2. Description of the Related Art In recent years, semiconductor lasers having a short oscillation wavelength have been developed, and the wavelength of a conventionally used laser has been reduced to 78 nm.
There is a demand for an optical recording medium capable of high-density recording and reproduction using laser light having a wavelength shorter than 0 nm and 830 nm. Conventionally proposed optical recording media include magneto-optical recording media,
There are a phase change recording medium, a chalcogen oxide optical recording medium, an organic dye optical recording medium, and the like. Among these, the organic dye optical recording medium is inexpensive in cost and easy in the manufacturing process. Is considered to have an advantage.

At present, as an organic dye-based optical recording medium, a write-once compact disk (CD-R) of a type in which a metal layer having a high reflectance is laminated on an organic dye layer is mass-produced and widely known. A write-once digital versatile disk (DVD-R) has also been developed as a high-density organic dye-based optical recording medium for recording with a red semiconductor laser having a shorter wavelength than the laser used for recording and reproducing the CD-R. Has been However, as laser oscillation of shorter wavelengths becomes possible, lasers with shorter wavelengths than DVD-R, that is, blue semiconductor lasers (wavelengths of 350 nm to 530 nm), capable of recording at even higher densities, will be used in the future. The need for an optical recording medium capable of recording and reproduction is increasing.

[0004]

Generally, the optical recording medium used as a CD-R or DVD-R has a low reflectance and cannot perform good recording / reproducing when recording / reproducing with a short wavelength blue semiconductor laser. Have a problem. Accordingly, it is necessary to select a dye having an appropriate optical property and decomposition behavior for a blue semiconductor laser as the dye used in the recording layer. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an organic dye-based optical recording medium that can be recorded or reproduced by a blue semiconductor laser.

[0005]

Means for Solving the Problems The inventors of the present invention have studied to achieve the above object, have found a specific dye having high sensitivity to a blue semiconductor laser, and have reached the present invention.
That is, the gist of the present invention is an optical recording medium in which a recording layer capable of recording or reproducing information by a laser is provided on a substrate, wherein the recording layer contains a dye represented by the following general formula (1). An optical recording medium characterized in that:

[0006]

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Wherein the rings A and A ′ are the same or different and each represents an optionally substituted aromatic hydrocarbon ring, aromatic heterocyclic ring, sandwich molecule or semi-sandwich molecule. (It may have a substituent.) The wavelength of the laser used for recording or reproducing the optical recording medium of the present invention is preferably 350 nm to 530 nm.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The organic dye contained in the recording layer of the optical recording medium of the present invention is represented by the general formula (1). In the general formula (1), rings A and A ′ are the same or different and each represents an aromatic hydrocarbon ring, an aromatic heterocyclic ring, a sandwich molecule or a semi-sandwich molecule. Ring A and A '
Specific examples of the aromatic hydrocarbon ring represented by include an aromatic monocyclic ring such as a benzene ring and an aromatic polycyclic ring such as a naphthalene ring and an anthracene ring, and these may further have a substituent. .

The substituents on the aromatic hydrocarbon ring include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-heptyl and the like. A linear or branched alkyl group having 1 to 18 carbon atoms; a linear or branched alkylthio group and an alkoxy group having 1 to 18 carbon atoms corresponding to the alkyl group; and carbon atoms such as cyclopropyl group, cyclopentyl group, cyclohexyl group, and adamantyl group. A cyclic alkyl group having 3 to 18 carbon atoms; a linear or branched alkenyl group having 2 to 18 carbon atoms such as a vinyl group, a propenyl group, and a hexenyl group; a linear or branched alkenyl group having 2 to 18 carbon atoms corresponding to the alkenyl group; Alkenyloxy group; having 3 to 18 carbon atoms, such as cyclopentenyl group and cyclohexenyl group;
A cyclic alkenyl group; a heterocyclic group such as a 2-thienyl group, a 2-pyridyl group or a furfuryl group; an aryl group having 6 to 18 carbon atoms such as a phenyl group, a tolyl group, a xylyl group, and a mesityl group;
Aralkyl groups such as benzyl group and phenethyl group; linear or branched acyl groups having 2 to 18 carbon atoms such as acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group and isovaleryl group; trifluoromethyl group, pentafluoro Ethyl group, heptafluoro-n-propyl group, heptafluoroisopropyl group, perfluoro-n-butyl group,
A linear or branched fluoroalkyl group having 1 to 18 carbon atoms such as a perfluoro-sec-butyl group or a perfluoro-tert-butyl group; and 1 carbon atom corresponding to the fluoroalkyl group
To 18 linear or branched fluoroalkylthio and fluoroalkoxy groups; halogen atoms such as fluorine, chlorine, and bromine; nitro; cyano; isocyano; cyanato; isocyanato; thiocyanato; isothiocyanato; hydroxy group; formyl group; a sulfonic acid group and sulfonate; carboxyl group; -NR ₁
A sulfonamide group represented by -NHSO ₂ R _5;; carbamate group represented by -NHCOOR _4; acylamino group represented by -NHCOR _3; amino group represented by R ₂ -C
Carboxylic acid ester group represented by OOR _6; -CONR ₇
Sulfamoyl group represented by -SO ₂ NR ₉ R _10;; carbamoyl groups represented by R ₈ sulfonate groups represented by -SO ₃ R ₁₁ can be mentioned. These substitution positions are not particularly limited, and the number of substituents is 0 to 5, preferably 0 to 3. When it has a plurality of substituents, they may be the same or different.

R _{1 to} R ₁₁ each represent a hydrogen atom, a linear or branched alkyl group which may be substituted, a cyclic alkyl group which may be substituted, an alkenyl group which may be substituted, Represents an optionally substituted cyclic alkenyl group, an optionally substituted aryl group, or an optionally substituted aralkyl group (substituents are the same as those described above).

The alkyl group, the cyclic alkyl group, the alkenyl group, the cyclic alkenyl group, the aryl group and the heterocyclic group included in these substituents further include a methoxy group, an ethoxy group, an n-propoxy group and an isopropoxy group. , N-butoxy group, sec-butoxy group, tert-butoxy group, etc.
Alkoxy groups having 2 to 12 carbon atoms such as methoxymethoxy group, ethoxymethoxy group, propoxymethoxy group, ethoxyethoxy group, propoxyethoxy group, methoxybutoxy group; methoxymethoxymethoxy group, methoxymethoxyethoxy group A methoxyethoxymethoxy group, a methoxymethoxyethoxy group,
An alkoxyalkoxyalkoxy group having 3 to 15 carbon atoms such as an ethoxyethoxymethoxy group; an aryl group having 6 to 12 carbon atoms such as a phenyl group, a tolyl group, and a xylyl group (these may be further substituted with a substituent). An aryloxy group having 6 to 12 carbon atoms such as a phenoxy group, a tolyloxy group, a xylyloxy group, and a naphthyloxy group; an alkenyloxy group having 2 to 12 carbon atoms such as an allyloxy group and a vinyloxy group; a cyano group; a nitro group; An amino group; an alkylamino group having 1 to 10 carbon atoms such as an N, N-dimethylamino group, an N, N-diethylamino group; a carbon number such as a methylsulfonylamino group, an ethylsulfonylamino group, and an n-propylsulfonylamino group; 1-6
An alkylsulfonylamino group; a halogen atom such as a fluorine atom, a chlorine atom, and a bromine atom; Alkoxycarbonyl group; having 2 to 7 carbon atoms such as methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, etc.
Alkylcarbonyloxy group; substituted with an alkoxycarbonyloxy group having 2 to 7 carbon atoms such as a methoxycarbonyloxy group, an ethoxycarbonyloxy group, an n-propoxycarbonyloxy group, an isopropoxycarbonyloxy group, and an n-butoxycarbonyloxy group. It may be. Further, a cyclic alkyl group included in the above substituent,
A linear or branched alkenyl group is a methyl group, an ethyl group,
C 1-18 carbon atoms such as propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-heptyl group
May be substituted with a linear or branched alkyl group.

When the rings A and A ′ represent an aromatic hydrocarbon ring, they are unsubstituted or substituted as a linear or branched alkyl group having 1 to 6 carbon atoms, a linear or branched alkyl group having 1 to 6 carbon atoms. A branched alkoxy group, a C1-C6 fluoroalkyl group, a C1-C6 fluoroalkoxy group, a C1-C6 linear or branched alkylthio group, a C1-C6 linear or branched A hydrocarbon ring having a fluoroalkylthio group, a halogen atom, a nitro group, a cyano group, a carboxyl group, a hydroxy group, a substituted or unsubstituted amino group is preferred.

Examples of the aromatic heterocyclic ring represented by rings A and A 'include, for example, those described below. The type thereof is not limited, but a 5- to 10-membered ring is preferable. These aromatic heterocycles may be bonded to a cyanovinyl group at any position, and may further have a substituent other than the bond. Examples of the substituent include the same groups as those described above for the aromatic hydrocarbon ring.

[0014]

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The sandwich molecule or semi-sandwich molecule represented by rings A and A ′ is such that a metal atom is located between two aromatic plane rings (eg, cyclopentadiene, cyclobutadiene, benzene, cyclooctatetraene, etc.). It represents a molecule having a sandwiched structure or a semi-sandwich type molecule composed of one aromatic planar ring and a metal. The planar ring may have a substituent other than the bonding portion. Examples of the substituent include the same groups as those described above for the aromatic hydrocarbon ring. In the case of two planar rings, the two may be the same or different, depending on the type of metal. A halogen atom, a CO molecule, an alkene molecule, an alkyne molecule or the like may be bonded as a ligand in addition to the plane ring and the metal. Examples of the sandwich molecule and the semi-sandwich molecule include those exemplified below.

[0016]

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Among these sandwich molecules, molecules whose planar rings have the same reactivity as aromatic ones are preferred, and cyclopentadienyl complexes are particularly preferred. As the metal atom, a transition metal atom is preferable. Particularly preferred as a sandwich molecule is ferrocene.

Preferred as the substituent of the benzene ring B are a straight-chain or branched alkyl group having 1 to 4 carbon atoms, a straight-chain or branched fluoroalkyl group having 1 to 4 carbon atoms, and a straight-chain or branched fluoroalkyl group having 1 to 4 carbon atoms. Chain or branched alkoxy group, having 1 to 1 carbon atoms
And 4 straight-chain or branched fluoroalkoxy groups, halogen atoms, nitro groups, and hydroxy groups. Particularly preferred as the benzene ring B is a benzene ring in which 0 to 4 alkyl groups, halogen atoms, alkoxy groups, hydroxy groups and the like are substituted. When it has a plurality of substituents, they may be the same or different.

The dye represented by the general formula (1) is, for example,
As shown in the following formula, it can be obtained by subjecting a compound having an aldehyde group to a condensation reaction with paraphenylenediacetonitrile in accordance with a conventional method.

[0020]

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(Wherein rings A, A ′ and B are represented by the general formula (1)
Has the same significance as In the above reaction, when one type of aldehyde compound is used (that is, when the rings A and A ′ are the same), a compound symmetrical about the benzene ring B is obtained as the compound of the general formula (1), When two kinds of aldehyde compounds are used, an asymmetric compound or a mixture of an asymmetric compound and an asymmetric compound is obtained. As the dye of the optical recording medium of the present invention, any of symmetric and asymmetric compounds can be used, but a symmetric compound is preferable from the viewpoint of synthesis and purification. Among the dyes represented by the general formula (1), a dye represented by the following general formula (2) and having a symmetrical structure around benzene is particularly preferable.

[0022]

Embedded image (In the formula, ring A ₁ represents an optionally substituted aromatic hydrocarbon ring, heteroaromatic ring, or cyclopentadienyl complex.) Preferred examples of the compound represented by the general formula (1) are as follows. However, the dye used in the present invention is not limited to these.

[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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The dye represented by the general formula (1) is excellent in forming a thin film when, for example, a recording layer is formed from a solution containing the dye. In addition, the recording layer containing the dye of the general formula (1) has an absorption in a short wavelength region of 350 nm to 500 nm suitable for recording and reproduction by a laser beam. It is extremely useful as a dye for use in optical recording media. The optical recording medium of the present invention is basically composed of a substrate and a recording layer containing the dye of the general formula (1). , A protective layer or the like may be provided. An example of a preferable layer configuration includes a medium having a high reflectance in which a metal reflective layer such as gold, silver, and aluminum and a protective layer are provided on the recording layer. Hereinafter, the optical recording medium of the present invention will be described using a medium having this structure as an example.

The material of the substrate in the optical recording medium of the present invention may basically be transparent as long as the wavelengths of the recording light and the reproducing light are used. Examples of such a material include a resin such as an acrylic resin, a methacrylic resin, a polycarbonate resin, a polyolefin resin (especially an amorphous polyolefin), a polyester resin, a polystyrene resin, an epoxy resin, and a glass. Alternatively, a material in which a resin layer made of a radiation-curable resin such as a photo-curable resin is provided on glass can be used. In terms of high productivity, cost, and moisture absorption resistance, injection molded polycarbonate is preferred. Amorphous polyolefin is preferred from the viewpoint of chemical resistance and moisture absorption resistance, and a glass substrate is preferred from the viewpoint of high-speed response. A resin substrate or a resin layer may be provided in contact with the recording layer, and a guide groove or pit for recording / reproducing light may be provided on the resin substrate or the resin layer. When the guide groove is spiral, the groove pitch is preferably about 0.5 to 1.2 μm.

A recording layer containing a dye represented by the general formula (1) is formed on a substrate or, if necessary, on an undercoat layer. As a method for forming the recording layer, a commonly used thin film forming method such as a vacuum evaporation method, a sputtering method, a doctor blade method, a casting method, a spin coating method, and an immersion method can be adopted. The spin coating method is preferred from the viewpoint of mass productivity and cost. Further, from the viewpoint that a recording layer having a uniform thickness can be obtained, a vacuum deposition method or the like is more preferable than a coating method.
In the case of film formation by spin coating, the number of rotations is 500-5000r
pm is preferable, and after spin coating, a treatment such as heating or contact with a solvent vapor may be performed in some cases.

When forming the recording layer by a coating method such as a doctor blade method, a casting method, a spin coating method, and a dipping method, the coating solvent is not particularly limited as long as it does not attack the substrate. For example, ketone alcohol solvents such as diacetone alcohol and 3-hydroxy-3-methyl-2-butanone; cellosolve solvents such as methyl cellosolve and ethyl cellosolve; chain hydrocarbon solvents such as n-hexane and n-octane ; Cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane,
Cyclic hydrocarbon solvents such as n-butylcyclohexane, tert-butylcyclohexane, and cyclooctane; Perfluoroalkyl alcohol solvents such as tetrafluoropropanol, octafluoropentanol, and hexafluorobutanol; methyl lactate, ethyl lactate, and methyl isobutyrate And the like. In the case of the vacuum evaporation method, for example, the compound of the present invention,
If necessary, other recording layer components such as other dyes and various additives,
After placing in a crucible placed in a vacuum vessel and evacuating the vacuum vessel to about 10 ⁻² to 10 ⁻⁵ Pa with a suitable vacuum pump, the crucible is heated to evaporate the recording layer components and face the crucible. By vapor deposition on the substrate placed
A recording layer is formed.

Further, the recording layer may be a transition metal chelate compound (eg, acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-α) as a singlet oxygen quencher in order to improve the stability and light resistance of the recording layer. -Diketone, etc.) or a recording sensitivity improver such as a metal compound for improving the recording sensitivity. Here, the metal compound refers to a compound in which a metal such as a transition metal is contained in the compound in the form of an atom, an ion, a cluster, or the like. Dihydroxyazobenzene-based complex,
Dioxime-based complexes, nitrosoaminophenol-based complexes,
Organometallic compounds such as pyridyltriazine-based complexes, acetylacetonate-based complexes, metallocene-based complexes, and porphyrin-based complexes are exemplified. The metal atom is not particularly limited, but is preferably a transition metal.

Further, if necessary, other types of dyes may be used in combination. Other types of dyes are not particularly limited as long as they have appropriate absorption mainly in a recording laser wavelength range. Also, 770-8 like CD-R
Supports recording with laser light in multiple wavelength ranges by using a dye suitable for recording with a near-infrared laser with a wavelength selected from 30 nm or a red laser selected from 620 to 690 nm such as DVD-R The optical recording medium can also be used.

Other dyes include metal-containing azo dyes,
Phthalocyanine dye, naphthalocyanine dye, cyanine dye, azo dye, squarylium dye, metal-containing indoaniline dye, triarylmethane dye,
Examples include merocyanine dyes, azulenium dyes, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, xanthene dyes, oxazine dyes, and pyrylium dyes.

Further, if necessary, a binder, a leveling agent, an antifoaming agent and the like can be used in combination. Preferred binders include polyvinyl alcohol, polyvinyl pyrrolidone, nitrocellulose, cellulose acetate, ketone resin, acrylic resin, polystyrene resin, urethane resin, polyvinyl butyral, polycarbonate, polyolefin and the like. The thickness of the recording layer is
Although the suitable film thickness varies depending on the recording method and the like, it is not particularly limited, but is usually 50 to 300 nm.

A reflective layer may be formed on the recording layer, and its thickness is preferably 50 to 300 nm. As a material of the reflection layer, a material having a sufficiently high reflectance at the wavelength of the reproduction light, for example, Au, Al, Ag, Cu, Ti, Cr, Ni, Pt, Ta,
Cr and Pd metals can be used alone or as an alloy. Among them, Au, Al, and Ag have high reflectivity and are suitable as the material of the reflective layer. In addition to these as main components, the following may be included. For example, Mg, Se, H
f, V, Nb, Ru, W, Mn, Re, Fe, Co, Rh, Ir, Cu, Z
Metals and metalloids such as n, Cd, Ga, In, Si, Ge, Te, Pb, Po, Sn, and Bi can be mentioned. Among them, those containing Ag as a main component are particularly preferable because they are inexpensive, easily reflect a high reflectance, and when a print receiving layer described later is provided, a white and beautiful ground color can be obtained. Here, the main component means one having a content of 50% or more.

It is also possible to form a multilayer film by alternately stacking low-refractive-index thin films and high-refractive-index thin films of a material other than a metal and use it as a reflective layer. Examples of a method for forming the reflective layer include a sputtering method, an ion plating method, a chemical vapor deposition method, and a vacuum vapor deposition method. In addition, a known inorganic or organic intermediate layer for improving reflectance, improving recording characteristics, improving adhesion, etc. on the substrate or below the reflective layer,
An adhesive layer can also be provided.

The material of the protective layer formed on the reflective layer is not particularly limited as long as it protects the reflective layer from external force. Examples of the organic material include a thermoplastic resin, a thermosetting resin, an electron beam curable resin, and a UV curable resin. Further, as inorganic substances, SiO ₂ , Si
N ₄ , MgF ₂ , SnO _{2 and the} like can be mentioned.

The thermoplastic resin, thermosetting resin, etc. can be formed by dissolving in a suitable solvent, applying a coating solution, and drying. The UV curable resin can be formed by preparing a coating solution as it is or by dissolving it in an appropriate solvent, applying the coating solution, and irradiating with UV light to cure the resin. As UV curable resin,
For example, acrylate resins such as urethane acrylate, epoxy acrylate, and polyester acrylate can be used. These materials may be used alone or as a mixture, or may be used as a multilayer film instead of a single layer.

As a method for forming the protective layer, a coating method such as a spin coating method or a casting method, a sputtering method, a chemical vapor deposition method, or the like is used as in the case of the recording layer. Of these, the spin coating method is preferable. The thickness of the protective layer is generally 0.1 to 1
Although it is in the range of 00 μm, it is preferably 3 to 30 μm in the present invention.

Further, a substrate may be further bonded to the reflective layer surface, or two optical recording media may be bonded to each other with the reflective layer surfaces facing each other. An ultraviolet curable resin layer, an inorganic thin film, or the like may be formed on the mirror surface of the substrate to protect the surface or prevent adhesion of dust and the like. Note that a print receiving layer that can be written (printed) with various types of printers such as ink jet and thermal transfer, or various writing instruments may be provided on a surface other than the recording / reproducing light incident surface.

The laser beam used for the optical recording medium of the present invention is preferably shorter in wavelength for high-density recording, but a laser beam of 350 to 530 nm is particularly preferred. Representative examples of such laser light include laser light having center wavelengths of 410 nm and 515 nm. An example of laser light having a wavelength in the range of 350 to 530 nm can be obtained by using a high-power semiconductor laser of 410 nm blue or 515 nm turquoise.Others, for example, (a) a fundamental oscillation wavelength of 740 to 740 nm 960n
m, a semiconductor laser capable of continuous oscillation, or (b) excited by a semiconductor laser, and having a fundamental oscillation wavelength of 740 to 960.
It can also be obtained by wavelength conversion of any of solid-state lasers capable of continuous oscillation of nm using a second harmonic generation element (SHG).

The SHG may be any piezo element that does not have inversion symmetry.
ADP, BNN, KN, LBO, compound semiconductor, and the like are preferable. As a specific example of the second harmonic, the fundamental oscillation wavelength is
In the case of a semiconductor laser of 860 nm, its harmonic is 430 nm, and in the case of a solid-state laser pumped by a semiconductor laser, it is 4 which is the harmonic of a Cr-doped LiSrAlF ₆ crystal (having a fundamental oscillation wavelength of 860 nm).
30 nm and the like.

The recording on the optical recording medium of the present invention obtained as described above is performed by irradiating the recording layer provided on both sides or one side of the substrate with a laser beam focused to about 0.4 to 0.6 μm. In the portion irradiated with the laser beam, thermal deformation of the recording layer such as decomposition, heat generation, and dissolution occurs due to absorption of the laser beam energy, and the optical characteristics change. Reproduction of recorded information is performed by reading the difference in reflectance between a portion where optical characteristics have changed and a portion where optical characteristics have not changed using a laser beam.

[0045]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist. Example 1 (a) Production of dye

[0046]

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P-Phenylene diacetonitrile [I] 30
After dissolving 3 mg (1.94 mmol) in 10 ml of methanol under argon replacement, 3.51 ml of a 10% methanol solution of tetrabutylammonium hydroxide was added, and the mixture was added at room temperature for 30 minutes.
Stirred. Then, 770 mg (3.60 mmol) of ferrocene carbaldehyde represented by the above structural formula [II] was added to the solution, and the mixture was further stirred at room temperature for 24 hours. The resulting precipitate was collected by filtration, filtered by hot filtration, and recrystallized from ethyl acetate to give 1,4-bis (α-cyano-β-ferrocenylvinyl) benzene represented by the following structural formula [III]. 58
8 mg was obtained (55% yield).

[0048]

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(B) Evaluation The dye of the above structural formula [III] (λmax in chloroform =
365.5nm, molar extinction coefficient is 3.0 × 10 ⁴ ), sublimated by heating from room temperature to 350 ° C. under a pressure of 4 × 10 ⁻³ Pa using a vacuum evaporation apparatus, and injection with a diameter of 120 mm and a thickness of 1.2 mm. It was deposited on a molded polycarbonate resin substrate. The maximum absorption wavelength (λmax) of the formed deposited film was 362 nm.

Example 2 (a) Production of Dye

[0051]

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P-Phenylene diacetonitrile [I] 33
3 mg (2.13 mmol) was dissolved in 10 ml of methanol under argon replacement, and 3.51 ml of a 10% methanol solution of tetrabutylammonium hydroxide was added, and the mixture was added at room temperature for 30 minutes.
Stirred. Then, 0.56 ml (4.63 mmol) of p-methoxybenzaldehyde represented by the above structural formula [IV] was added to this solution, and the mixture was further stirred at room temperature for 24 hours. The resulting precipitate was collected by filtration, filtered hot, and further recrystallized from ethyl acetate to give 1,4-bis (α-cyano-β-methoxyphenylvinyl) benzene represented by the following structural formula [V]. Was obtained (yield 84%).

[0053]

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(B) Evaluation The dye of the above structural formula [V] (λmax = 3 in chloroform)
77 nm, molar extinction coefficient of 5.2 × 10 ⁴ ) was sublimated by heating from room temperature to 350 ° C. under a pressure of 4 × 10 ⁻³ Pa using a vacuum evaporation apparatus, and injection was performed with a diameter of 120 mm and a thickness of 1.2 mm. It was deposited on a molded polycarbonate resin substrate. The maximum absorption wavelength (λmax) of the obtained deposited film was 349 nm.

On the vapor-deposited films obtained in Examples 1 and 2, a silver film was formed by a sputtering method or the like to form a reflective layer.
In addition, UV curable resin is applied by spin coating etc.
By curing by irradiation to form a protective layer, an optical recording medium can be obtained. This optical recording medium has a λma
Judging from the value of x, it is clear that recording / reproduction with a semiconductor laser having a center wavelength of, for example, 410 nm is possible.

[0056]

The dye of the general formula (1) is capable of forming a thin film having an absorption suitable for recording / reproducing by short-wavelength laser light and has excellent film formability. A recording medium having a recording layer using is expected as an optical recording medium for recording and reproduction corresponding to a short wavelength laser.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H111 FB42 4H056 CA02 CB03 CC02 CE01 FA06 5D029 JA04

Claims (5)

[Claims] 1. An optical recording medium having a recording layer capable of recording or reproducing information by a laser on a substrate, wherein the recording layer contains a dye represented by the following general formula (1). Characteristic optical recording medium. Embedded image (Wherein rings A and A ′ are the same or different,
Represents an optionally substituted aromatic hydrocarbon ring, aromatic heterocyclic ring, sandwich molecule or semi-sandwich molecule. The benzene ring B may further have a substituent. ) 2. The dye contained in the recording layer is a dye represented by the following general formula (2).
4. The optical recording medium according to claim 1. Embedded image (In the formula, ring A ₁ represents an optionally substituted aromatic hydrocarbon ring, aromatic heterocyclic ring or cyclopentadienyl complex.) 3. The optical recording medium according to claim 2, wherein in the general formula (2), the ring A ₁ represents an aromatic hydrocarbon ring or a ferrocene molecule which may be substituted. 4. The optical recording medium according to claim 3, wherein in the general formula (2), the ring A ₁ is an optionally substituted benzene ring or ferrocene. 5. The laser wavelength for recording or reproducing information is 35.
5. The optical recording medium according to claim 1, wherein the optical recording medium has a thickness of 0 nm to 530 nm.