JP2002096558A - Optical information recording medium and method of recording information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information recording medium which enables recording and reproduction of information by easing thereon a laser light of a wavelength 550 nm or below and of a shorter wavelength than the laser light used for recording and reproduction of information for CD-R or DVD-R, particularly of a wavelength 450 nm or below, and has excellent recording characteristics, and a method of recording information which enables high-density recording of the information by using the optical information recording medium. SOLUTION: The optical information recording medium has on a base a recording layer whereon the information can be recorded by casting of the laser light. The recording layer contains an azole compound expressed by the following general formula (I): A1-L1m (-A2)n. [In the formula, A1 and A2 denote respectively azolyl groups which may have substituents independently, and n an integer of 1-5. L1 denotes a connecting group of an n+1 valance pi electron conjugation series, and m denotes 0 or 1, while n is 1 when m is 0. A1 and A2 may be identical with or different from each other, and a plurality of groups A1 may be identical with or different from each other when n is an integer of 2 or more. A1 and L1, A2 and L1, or A1 and A2, may be so bonded to each other as to form a ring].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium and an information recording method, and more particularly to an optical information recording medium and an information recording method capable of recording and reproducing information by irradiating a laser beam. is there. In particular, wavelength 5
The present invention relates to an optical information recording medium suitable for recording information by irradiating a short wavelength laser beam of 50 nm or less, and an information recording method using the optical information recording medium.

[0002]

2. Description of the Related Art Conventionally, an optical information recording medium (optical disk) on which information can be recorded only once by a laser beam has been known. This optical disc is a write-once CD (so-called CD-
R), a typical structure of which is formed by laminating a recording layer made of an organic dye, a light reflecting layer made of a metal such as gold, and a protective layer made of a resin in this order on a transparent disk-shaped substrate. is there. The recording of information on the CD-R is performed by irradiating the CD-R with near-infrared laser light (usually a laser light having a wavelength around 780 nm), and the irradiated portion of the recording layer emits the light. The temperature is locally increased by absorption, and information is recorded by changing the optical characteristics of the portion due to a physical or chemical change (for example, generation of pits). On the other hand, reading (reproduction) of information is also performed by irradiating the CD-R with a laser beam having the same wavelength as the recording laser beam, and changes the optical characteristics of the recording layer (the recording portion). This is performed by detecting a difference in reflectance with a part that has not been recorded (unrecorded part).

Recently, an optical disc called a write-once digital versatile disc (so-called DVD-R) has been proposed and put into practical use as an optical information recording medium capable of recording at a higher density than a CD-R. I have. This DVD-R
Is a structure in which a recording layer containing an organic dye, a light reflection layer, and a protective layer are laminated in this order on a transparent disk-shaped substrate, and two disks are laminated with the recording layer inside, or And a disc-shaped protective substrate of the same shape as that of the above, with the recording layer inside, and a transparent disc-shaped substrate with a guide groove (pre-groove) for tracking the laser light to be irradiated. , CD-R with a narrow groove width of less than half (0.74 to 0.8 μm). Recording and reproduction of information on the DVD-R are performed by irradiating a visible laser beam (usually a laser beam having a wavelength in the range of 630 nm to 680 nm), and the density is higher than that of the CD-R. Recording is possible.

Recently, networks such as the Internet and high-definition televisions have rapidly become widespread. Also, HDT
V (High Definition Television) is starting to air soon. Under such circumstances, there is a need for a large-capacity recording medium capable of simply and inexpensively recording image information. At present, DVD-R plays a sufficient role as a large-capacity recording medium, but demands for large-capacity and high-density are increasing, and it is also necessary to develop a recording medium that can meet these demands. . For this reason, DVD-R
A recording medium having a larger capacity capable of performing high-density recording with light having a shorter wavelength than that of the recording medium is being developed.
For example, JP-A-4-74690, JP-A-8-127
Nos. 174, 11-53758 and 11-3
Nos. 34204, 11-334205, 1
1-334206, 11-334207, JP-A-2000-43423, 2000-1
JP 08513, JP 2000-113504 A,
JP-A-2000-149320 and JP-A-2000-149320
No. 58818 discloses an optical information recording medium having a recording layer containing an organic dye, by irradiating a laser having a wavelength of 530 nm or less from the recording layer side to the light reflection layer side to record and reproduce information. A playback method is disclosed. In this method, an optical disk having a recording layer containing a porphyrin compound, an azo dye, a metal azo dye, a quinophthalone dye, a trimethine cyanine dye, a dicyanovinylphenyl skeleton dye, a coumarin compound, and the like,
Information is recorded and reproduced by irradiating blue (wavelength 430 nm, 488 nm) or blue-green (wavelength 515 nm) laser.

[0005]

However, according to the study of the present inventors, the optical disk described in the above-mentioned publication cannot obtain the sensitivity required for practical use, and furthermore, such as reflectance and modulation degree. It was also found that other recording characteristics were not at a satisfactory level, and that further improvement was required. In particular, in the optical disc described in the above publication, the recording characteristics deteriorated when a laser beam having a wavelength of 450 nm or less was irradiated. The present invention has been made in view of the above-mentioned problems of the prior art.
Laser light having a shorter wavelength than the laser light used for recording and reproducing information on / from a DVD-R or DVD-R, particularly a wavelength of 450 nm
An object of the present invention is to provide an optical information recording medium capable of recording and reproducing information by irradiating the following laser beam and having excellent recording characteristics. A second object of the present invention is to irradiate a laser beam having a wavelength of 550 nm or shorter and shorter than a laser beam used for recording and reproduction of a CD-R or DVD-R, particularly a laser beam having a wavelength of 450 nm or shorter. To provide an information recording method capable of recording information at high density.

[0006]

In order to achieve the first object, an optical information recording medium according to the present invention has a recording layer on a substrate on which information can be recorded by irradiating a laser beam. An optical information recording medium, wherein the recording layer contains an azole compound represented by the following general formula (I).

[0007]

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[In the formula, A ¹ and A ² each independently represent an azolyl group which may have a substituent, and n represents an integer of 1 to 5. L ¹ represents an n + 1-valent π-electron conjugated linking group.
m represents 0 or 1, and when m is 0, n is 1. A
¹ and A ² may be the same or different. A plurality of A ^{2 s} when n is an integer of 2 or more may be the same or different. A ¹ and L ¹ , A ² and L ¹ ,
Alternatively, A ¹ and A ² may combine with each other to form a ring. ]

In the general formula (I), A ¹ and A ²
The azolyl groups represented by are each independently an oxazolyl group, a thiazolyl group, or an imidazolyl group,
Alternatively, it is preferable that the azolyl groups represented by A ¹ and A ² are each independently a benzoxazolyl group, a benzothiazolyl group, or a benzimidazolyl group. Also, m
Is preferably 1, and n is preferably 1.

In the general formula (I), the π-electron conjugated linking group represented by L ¹ is represented by — (CH ＝ CH) _k —
(K: an integer of 1 to 3),-(C≡C) _h- (h: an integer of 1 to 3), a connecting group selected from the group consisting of an arylene group and a heteroarylene group, or The linking group is preferably a linking group formed by combining two or more selected linking groups.

The azole compound represented by the general formula (I) is more preferably a compound represented by the following general formula (IA).

[0012]

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Wherein X and Y are each independently —O
—, —NR ¹ — or —S—, R ¹ represents an alkyl group, an aryl group, or a heterocyclic group, and L ² represents a divalent π-electron conjugated linking group. R ² and R ³ each independently represent a substituent, and s and t each represent an integer of 0 to 4. When s is an integer of 2 or more, a plurality of R ^{2 s} may be the same or different, and may combine with each other to form a ring. When t is an integer of 2 or more, a plurality of R ^{3 s} may be the same or different, and may combine with each other to form a ring. ]

In the general formula (IA), the above L
^The π-electron conjugated linking group represented by ² is-(CH = CH) _k
-(K: an integer from 1 to 3),-(C≡C) _h- (h: 1
And a linking group selected from the group consisting of an arylene group and a heteroarylene group, or a linking group formed by combining two or more kinds of linking groups selected from these groups.

The above-mentioned optical information recording medium has a surface on the side where the pregroove is formed of a transparent disc-shaped substrate having a pregroove formed with a track pitch of 0.2 to 0.8 μm on one of the surfaces. In addition, a structure in which a recording layer on which information can be recorded by laser light irradiation can be formed. Further, the above-mentioned optical information recording medium may further be provided with a light reflection layer and / or a protection layer made of metal.

In order to achieve the second object,
An information recording method according to an eleventh aspect is characterized in that information is recorded by irradiating the optical information recording medium of the present invention with a laser having a wavelength of 550 nm or less.

According to the study of the present inventor, the azole represented by the general formula (I) is formed on a recording layer of an optical information recording medium having a recording layer capable of recording information by irradiating a laser beam on a substrate. By containing the compound, it has a high sensitivity to a laser beam having a wavelength of 550 nm or less, and even a short wavelength of 450 nm or less, and has a high reflectance and a good recording characteristic of giving a high degree of modulation. An optical information recording medium can be obtained. Further, the optical information recording medium can be irradiated with a laser beam having a wavelength of 550 nm or less, and further, a wavelength of 450 nm or less to record information at high density.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the optical information recording medium and the information recording method of the present invention will be described in detail.
The optical information recording medium of the present invention is an optical information recording medium of the present invention, which is an optical information recording medium having a recording layer on a substrate on which information can be recorded by irradiating a laser beam. It is characterized by containing an azole compound represented by the formula (I).

[0019]

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[In the formula, A ¹ and A ² each independently represent an azolyl group which may have a substituent, and n represents an integer of 1 to 5. L ¹ represents an n + 1-valent π-electron conjugated linking group.
m represents 0 or 1, and when m is 0, n is 1. A
¹ and A ² may be the same or different. A plurality of A ^{2 s} when n is an integer of 2 or more may be the same or different. A ¹ and L ¹ , A ² and L ¹ ,
Alternatively, A ¹ and A ² may combine with each other to form a ring. ]

In the general formula (I), preferred azolyl groups represented by A ¹ and A ² are oxazolyl,
Thiazolyl, imidazolyl and triazolyl, more preferably oxazolyl and thiazolyl, even more preferably oxazolyl, and 2-azolyl is preferred. Further, the azolyl group represented by A ¹ and A ² may form a condensed ring, and preferred examples of the condensed ring include a benzene ring, a naphthalene ring, an anthracene ring and a phenanthrene ring. And a naphthalene ring are preferred, and a benzene ring is particularly preferred. That is, as the azolyl group, a benzoxazolyl group, a benzothiazolyl group, and a benzimidazolyl group are particularly preferable.

Examples of the substituent of the azolyl group represented by A ¹ and A ² include those described below. A chain or cyclic alkyl group having 1 to 20 carbon atoms (for example, methyl, ethyl, isopropyl, cyclohexyl), an aryl group having 6 to 18 carbon atoms (for example, phenyl, chlorophenyl, 2,4-di-t-) Amylphenyl, 1-naphthyl), an aralkyl group having 7 to 18 carbon atoms (e.g., benzyl, anisyl),
20 alkenyl groups (eg, vinyl, 2-methylvinyl), alkynyl groups having 2 to 20 carbon atoms (eg, ethynyl, 2-methylethynyl, 2-phenylethynyl), halogen atoms (eg, F, Cl, Br) , I),
Cyano group, hydroxyl group, carboxyl group, acyl group having 2 to 20 carbon atoms (eg, acetyl, benzoyl, salicyloyl, pivaloyl), 1 to 20 carbon atoms
An alkoxy group (e.g., methoxy, butoxy, cyclohexyloxy), an aryloxy group having 6 to 20 carbon atoms (e.g., phenoxy, 1-naphthoxy, toluoyl), an alkylthio group having 1 to 20 carbon atoms (e.g.,
Methylthio, butylthio, benzylthio, 3-methoxypropylthio), an arylthio group having 6 to 20 carbon atoms (eg, phenylthio, 4-chlorophenylthio),
An alkylsulfonyl group having 1 to 20 carbon atoms (for example,
Methanesulfonyl, butanesulfonyl), 6 carbon atoms
To 20 arylsulfonyl groups (eg, benzenesulfonyl, paratoluenesulfonyl), having 1 to 1 carbon atoms
7 carbamoyl groups (eg, unsubstituted carbamoyl,
Methylcarbamoyl, ethylcarbamoyl, n-butylcarbamoyl, dimethylcarbamoyl), having 1 carbon atom
To 16 amide groups (for example, acetamido, benzamido), and acyloxy groups having 2 to 10 carbon atoms (for example,
Acetoxy, benzoyloxy), having 2 to 10 carbon atoms
An alkoxycarbonyl group (e.g., methoxycarbonyl, ethoxycarbonyl), a 5- or 6-membered heterocyclic group (e.g., an aromatic heterocycle such as pyridyl, thienyl, furyl, thiazolyl, imidazolyl, and pyrazolyl);
Heterocyclic rings such as a pyrrolidine ring, a piperidine ring, a morpholine ring, a pyran ring, a thiopyran ring, a dioxane ring and a dithiolane ring).

Particularly preferred substituents are a chain or cyclic alkyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aralkyl group having 7 to 11 carbon atoms, and a carbon atom having 7 to 11 carbon atoms. An alkoxy group having 1 to 16 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, a halogen atom, an alkoxycarbonyl group having 2 to 17 carbon atoms, and 1 carbon atom
A carbamoyl group having 10 to 10 carbon atoms, an amide group having 1 to 10 carbon atoms, among which a chain or cyclic alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a carbon atom number An alkoxy group having 1 to 10, an aryloxy group having 6 to 10 carbon atoms, a chlorine atom, and 2 carbon atoms
To 11 alkoxycarbonyl groups, carbamoyl groups having 1 to 7 carbon atoms, and amide groups having 1 to 8 carbon atoms, and more preferred are chain branched or cyclic alkyl groups having 3 to 10 carbon atoms, It is an alkoxy group having 1 to 8 atoms.

The above substituent may further have a substituent, and examples of the substituent in this case include those described above.

In the general formula (I), π represented by L ¹
Preferred as the electron conjugated linking group are alkene, alkyne and a linking group selected from the group consisting of n + 1 valent residues obtained by removing a hydrogen atom from an aromatic compound, and two or more kinds of linking groups selected from these groups. It is an n + 1-valent linking group formed by combining linking groups. Among them,-(CH = C
H) _k -,-(C≡C) _h- , (k and h each represent an integer of 1 to 3), an arylene group (eg, phenylene, naphthylene, biphenylene, etc.) and a heteroarylene group (eg, thiophenylene, furanylene) , Pyrrolylene, pyrazylene, pyridazinylene, pyridylene, etc.), and a linking group formed by combining two or more kinds of linking groups selected from these groups. Also, [pi electron conjugated linking group represented by L ¹ may have a substituent, examples of substituents [pi electron conjugated linking group represented by L ^1, A ¹ and A ² Examples of the substituent of the azolyl group represented by the following can be given, and preferred substituents are also the same, but non-substitution is most preferred.

In the general formula (I), m represents 0 or 1, and n represents an integer of 1 to 5. When m is 0, n is 1. That is, when m = 1, the π-electron conjugated linking group represented by L ¹ is composed of ^one azolyl group represented by A ¹ and 1 to 5 azolyl groups represented by A ^2. When m = 0, the azolyl group represented by one A ¹ and the azolyl group represented by one A ² are directly bonded without a linking group. However, m and n are preferably 1.

The above A ¹ and A ² may be the same or different. Also, n is 2 or more the plurality of A ² each other when integer may be different may be identical to one another. Further, A ¹ and L ¹ , A ² and L ¹ , or A ¹ and A ² may be bonded to each other to form a ring.

As the azole compound represented by the general formula (I), a compound represented by the following general formula (IA) is particularly preferred.

[0029]

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Wherein X and Y are each independently —O
—, —NR ¹ — or —S—, R ¹ represents an alkyl group, an aryl group, or a heterocyclic group, and L ² represents a divalent π-electron conjugated linking group. R ² and R ³ each independently represent a substituent, and s and t each represent an integer of 0 to 4. When s is an integer of 2 or more, a plurality of R ^{2 s} may be the same or different, and may combine with each other to form a ring. When t is an integer of 2 or more, a plurality of R ^{3 s} may be the same or different, and may combine with each other to form a ring. ]

In the general formula (IA), X and Y are preferably -O- or -S-, and particularly preferably -O- or -S-.
O- is preferred. An alkyl group, an aryl group representing R ¹ ,
The heterocyclic group is a chain or cyclic alkyl group having 1 to 20 carbon atoms (e.g., methyl, ethyl, isopropyl, cyclohexyl), or an aryl group having 6 to 18 carbon atoms (e.g., phenyl, chlorophenyl, 4-di-
t-amylphenyl, 1-naphthyl), 5- or 6-membered heterocyclic group (eg, pyridyl, thienyl, furyl,
Aromatic heterocycles such as thiazolyl, imidazolyl and pyrazolyl, pyrrolidine ring, piperidine ring, morpholine ring,
A heterocyclic ring such as a pyran ring, a thiopyran ring, a dioxane ring, and a dithiolane ring). Note that the above substituent may further have a substituent, in this case, as a substituent,
Examples of the substituent of the azolyl group represented by A ¹ and A ² can be given.

In formula (IA), the π-electron conjugated linking group represented by L ² is represented by L ¹ in formula (I).
Has the same meaning as the π-electron conjugated linking group represented by L ² , and the π-electron conjugated linking group represented by L ² is-(CH = CH)
_k- (k: an integer from 1 to 3),-(C≡C) _h- (h: 1
To an integer of from 3 to 3), an arylene group and a heteroarylene group, or a linking group formed by combining two or more linking groups selected from these groups. -, -C≡C- and phenylene are particularly preferred. Also, [pi electron conjugated linking group represented by L ² may have a substituent, examples of substituents [pi electron conjugated linking group represented by L ^2, A ¹ and A ² Examples of the substituent of the azolyl group represented by can be mentioned, and preferred substituents are also the same,
Unsubstituted is most preferred.

Examples of the substituents represented by R ² and R ³ include those exemplified as the substituents of the azolyl group represented by A ¹ and A ² , and preferred substituents are also the same. . S and t represent an integer of 0 to 4. s is 2
In the case of the above integer, a plurality of R ² may be the same or different, or may be bonded to each other to form a ring. When t is an integer of 2 or more, a plurality of R ³
They may be the same or different from each other, or may be bonded to each other to form a ring.

The azole compounds represented by the general formula (I) may be bonded to each other at any position to form a multimer. In this case, each unit may be the same or different. Further, it may be bonded to a polymer chain of polystyrene, polymethacrylate, polyvinyl alcohol, cellulose or the like.

Preferred specific examples of the azole compound represented by the general formula (I) are shown below, but the present invention is not limited thereto.

[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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The azole compounds represented by the general formula (I) used in the present invention are described, for example, in JP-B-44-9739, JP-B-44-43025, and JP-B-44-23028.
And JP-A-45-771, Japanese Patent No. 2833790, and US Pat. No. 4,876,234, or a method similar thereto.

The azole compounds may be used alone or in combination of two or more. Further, the azole compound and other dye compounds may be used in combination as a recording material. Examples of dye compounds that can be used in combination include cyanine dyes, oxonol dyes, azo metal complexes, phthalocyanine dyes, pyrylium dyes, thiopyrylium dyes, azurenium dyes, squalilium dyes,
Examples include naphthoquinone dyes, triphenylmethane dyes, and triallylmethane dyes.

The optical information recording medium of the present invention is not particularly limited as long as it has a recording layer containing the azole compound represented by the above general formula (I) on a substrate. Applicable to media. The optical information recording medium of the present invention may have a configuration in which, for example, a recording layer, a light reflecting layer, and a protective layer are provided in this order on a disk-shaped substrate on which pregrooves having a constant track pitch are formed. Hereinafter, the configuration of the optical information recording medium will be described in detail in accordance with the manufacturing process, taking an optical information recording medium having a recording layer, a light reflecting layer, and a protective layer in this order on a disc-shaped substrate as an example.

The substrate of the optical information recording medium of the present invention can be arbitrarily selected from various materials used as the substrate of the conventional optical information recording medium. As a substrate material,
For example, glass, polycarbonate, acrylic resins such as polymethyl methacrylate, polyvinyl chloride, vinyl chloride resins such as vinyl chloride copolymers, epoxy resins, amorphous polyolefins and polyesters, and the like. Is also good. Note that these materials can be used in the form of a film or a rigid substrate. Among the above materials, polycarbonate is preferred from the viewpoints of moisture resistance, dimensional stability, cost, and the like.

For the optical information recording medium of the present invention, in order to achieve a higher recording density, it is preferable to use a substrate on which a pre-groove having a narrower track pitch is formed than a CD-R or DVD-R. . In the case of the optical information recording medium of the present invention, the track pitch is preferably in the range of 0.2 to 0.8 µm, more preferably in the range of 0.25 to 0.6 µm, and more preferably in the range of 0.27 to 0. More preferably, it is in the range of 4 μm. Further, the depth of the pregroove is preferably in the range of 0.03 to 0.18 μm, more preferably in the range of 0.05 to 0.15 μm, and is in the range of 0.06 to 0.1 μm. Is particularly preferred.

An undercoat layer may be provided on the surface of the substrate on which the recording layer is provided, for the purpose of improving flatness, improving adhesive strength, and preventing deterioration of the recording layer. Examples of the material of the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, and chlorosulfonation. Polymeric substances such as polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate, etc .; and silane coupling agents And the like. The undercoat layer is formed by dissolving or dispersing the above substances in an appropriate solvent to prepare a coating solution, and then applying the coating solution to the substrate surface by a coating method such as spin coating, dip coating, or extrusion coating. can do.
The thickness of the undercoat layer is generally in the range of 0.005 to 20 μm, preferably in the range of 0.01 to 10 μm.

The recording layer is formed by dissolving a binder and the like in a solvent in addition to the azole compound to prepare a coating solution, and then applying the coating solution to the substrate surface to form a coating film and then drying. Can be performed.

Examples of the solvent for the coating solution include esters such as butyl acetate, ethyl lactate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane and chloroform; Amides such as formamide; hydrocarbons such as methylcyclohexane; ethers such as tetrahydrofuran, ethyl ether and dioxane; alcohols such as ethanol, n-propanol, isopropanol and n-butanol diacetone alcohol; 2,2,3,3-tetrafluoro Fluorinated solvents such as propanol; glycols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and propylene glycol monomethyl ether Or the like can be mentioned ether compounds. The above-mentioned solvents can be used alone or in combination of two or more in consideration of the solubility of the dye used. Various additives such as an antioxidant, a UV absorber, a plasticizer, and a lubricant may be further added to the coating solution according to the purpose.

When a binder is used, examples of the binder include natural organic high-molecular substances such as gelatin, cellulose derivatives, dextran, rosin, and rubber; and hydrocarbon-based substances such as polyethylene, polypropylene, polystyrene, and polyisobutylene. Resin, polyvinyl chloride, polyvinylidene chloride, vinyl resin such as polyvinyl chloride / polyvinyl acetate copolymer, acrylic resin such as polymethyl acrylate, polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resin, Synthetic organic polymers such as butyral resins, rubber derivatives, and initial condensates of thermosetting resins such as phenol / formaldehyde resins can be given. When a binder is used in combination as a material for the recording layer, the amount of the binder used is generally in the range of 0.01 times to 50 times (mass ratio) with respect to the dye, and preferably 0.1 to 50 times.
It is in the range of 1 to 5 times (mass ratio). The concentration of the dye in the coating solution thus prepared is generally 0.01%.
It is in the range of 10 to 10% by mass, preferably in the range of 0.1 to 5% by mass.

Examples of the coating method include a spray method, a spin coating method, a dipping method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method. The recording layer may be a single layer or a multilayer. The thickness of the recording layer is generally in the range of 20 to 500 nm, preferably in the range of 30 to 300 nm, more preferably 5 to 500 nm.
It is in the range of 0-100 nm.

The recording layer may contain various anti-fading agents in order to improve the light resistance of the recording layer.
Generally, a singlet oxygen quencher is used as an anti-fading agent. As the singlet oxygen quencher, those described in publications such as publicly known patent specifications can be used. A specific example thereof is disclosed in Japanese Patent Application Laid-Open No. 58-175.
Nos. 693, 59-81194, 60-18387
Nos. 60-19586, 60-19587, 60-35054, 60-36190, 60-
No. 36191, No. 60-44554, No. 60-445
No. 55, No. 60-44389, No. 60-44390
JP-A-60-54892, JP-A-60-47069, JP-A-63-209995, JP-A-4-25492, JP-B-1-38680, and JP-A-6-26028, and German Patent 350399. And pages 1141 of the Chemical Society of Japan, October 1992, and the like. Preferred examples of the singlet oxygen quencher include a compound represented by the following general formula (II).

[0054]

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(Wherein, R ²¹ represents an alkyl group which may have a substituent, and Q ⁻ represents an anion.) In the general formula (II), R ²¹ represents an optionally substituted carbon number. An alkyl group having 1 to 8 is generally used, and an unsubstituted alkyl group having 1 to 6 carbon atoms is preferable. Examples of the substituent of the alkyl group include a halogen atom (eg, F, Cl), an alkoxy group (eg, methoxy, ethoxy), an alkylthio group (eg,
Methylthio, ethylthio), acyl group (eg, acetyl,
Propionyl), acyloxy group (eg, acetoxy, propionyloxy), hydroxy group, alkoxycarbonyl group (eg, methoxycarbonyl, ethoxycarbonyl), alkenyl group (eg, vinyl), aryl group (eg,
Phenyl, naphthyl). Among these, a halogen atom, an alkoxy group, an alkylthio group,
Alkoxycarbonyl groups are preferred. Preferred examples of the anion of Q ⁻ include ClO ₄ ⁻ , AsF ₆ ⁻ , BF ₄ ⁻ , and SbF ₆ ⁻ . Table 1 shows examples of the compound represented by the general formula (II).

[0056]

[Table 1]

The amount of the anti-fading agent such as the singlet oxygen quencher is usually 0.1 to 50 to the amount of the dye.
%, Preferably 0.5 to 45% by mass.
, More preferably in the range of 3 to 40% by mass, particularly preferably in the range of 5 to 25% by mass.

It is preferable to provide a light reflection layer adjacent to the recording layer for the purpose of improving the reflectance at the time of reproducing information. The light-reflective substance, which is the material of the light-reflective layer, is a substance having a high reflectance with respect to a laser.
e, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, M
o, W, Mn, Re, Fe, Co, Ni, Ru, Rh,
Pd, Ir, Pt, Cu, Ag, Au, Zn, Cd, A
1, Ga, In, Si, Ge, Te, Pb, Po, S
Metals such as n and Bi and semimetals or stainless steel can be mentioned. These substances may be used alone, or in combination of two or more kinds, or may be used as an alloy. Of these, preferred are Cr,
Ni, Pt, Cu, Ag, Au, Al and stainless steel. Particularly preferred are Au metals, Ag metals, Al metals or alloys thereof, and most preferred are Ag metals.
Metal, Al metal, or an alloy thereof. The light reflecting layer can be formed on the substrate or the recording layer by, for example, vapor deposition, sputtering, or ion plating of the light reflecting substance. The thickness of the light reflecting layer is generally in the range of 10 to 300 nm,
It is preferably in the range of 200 nm.

It is preferable to provide a protective layer on the light reflecting layer or the recording layer for the purpose of physically and chemically protecting the recording layer and the like. Note that in the same manner as in the case of manufacturing a DVD-R type optical information recording medium, that is, in a case where two substrates are bonded together with the recording layer inside, it is not always necessary to provide a protective layer. Examples of the material used for the protective layer include SiO, SiO ₂ , MgF ₂ , and Sn.
Examples include inorganic substances such as O ₂ and Si ₃ N ₄ , and organic substances such as a thermoplastic resin, a thermosetting resin, and a UV-curable resin. The protective layer can be formed, for example, by laminating a film obtained by extrusion of a plastic on the reflective layer via an adhesive. Or vacuum deposition,
It may be provided by a method such as sputtering or coating. In the case of a thermoplastic resin or a thermosetting resin, they can also be formed by dissolving these in an appropriate solvent to prepare a coating solution, applying the coating solution, and drying. In the case of a UV-curable resin, it can also 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. Various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added to these coating solutions according to the purpose. The thickness of the protective layer is generally in the range from 0.1 μm to 1 mm. Through the above steps, a laminate in which the recording layer, the light reflecting layer and the protective layer are provided on the substrate, or the light reflecting layer, the recording layer and the protective layer are provided on the substrate can be manufactured.

The information recording method of the present invention is carried out, for example, as follows using the above-mentioned optical information recording medium. First, the optical information recording medium is set at a constant linear speed (1.2 for a CD format).
~ 1.4m / sec) or rotating at a constant angular speed,
Light for recording such as a semiconductor laser is irradiated from the substrate side or the protective layer side. By this light irradiation, the recording layer absorbs the light and locally raises the temperature, causing a physical or chemical change (for example, generation of pits) to change its optical characteristics, thereby recording information. It is thought to be done.
In the present invention, a semiconductor laser having an oscillation wavelength in the range of 390 to 550 nm is used as the recording light.

A preferred light source is 390-415 nm
Center oscillation wavelength composed of a blue-violet semiconductor laser having an oscillation wavelength within the range described above, a blue-green semiconductor laser having a center oscillation wavelength of 515 nm, an infrared semiconductor laser having a center oscillation wavelength of 850 nm, and an optical waveguide type wavelength conversion element (SHG). 425n
m blue-violet SHG laser. Among them, it is particularly preferable to use a blue-violet semiconductor laser or an SHG laser in terms of recording density. Reproduction of the information recorded as described above is performed by irradiating a laser beam from the substrate side while rotating the optical information recording medium at the same constant linear speed as described above, and detecting the reflected light. Can be.

The optical information recording medium of the present invention uses a conventional DVD
Similarly to -R, two laminates in which a recording layer and a light reflection layer are provided on a transparent disk-shaped substrate on which a pre-groove having a constant track pitch is formed such that each recording layer is on the inside. Can be used. Further, a structure in which this laminated body and a disk-shaped protective substrate having the same shape are bonded together with the recording layer facing inward may be adopted. When the bonding structure is adopted, for example, when the diameter of the transparent substrate is 1
The optical information recording medium having a thickness of 20 ± 3 mm and a thickness of 0.6 ± 0.1 mm is used.
It is adjusted to be 0.2 mm. This bonding may be performed using the UV curable resin used for forming the protective layer, or may be performed using a synthetic adhesive. Also,
It can also be laminated with double-sided tape.

The optical information recording medium of the present invention may have a structure in which, for example, a light reflecting layer, a recording layer, and a thin film protective layer are provided in this order on a disk-shaped substrate on which pregrooves having a constant track pitch are formed. it can. In this optical information recording medium, a thin protective layer is provided on the side opposite to the substrate having a predetermined thickness (1.2 mm for CD-R), and recording is performed by irradiating light from the thin protective layer side. The beam diameter of the laser light to be irradiated can be reduced to a small value, and high-density recording can be performed with light having a short wavelength of 450 nm or less.

The above-mentioned thin film protective layer has a thickness of 0.1 to
The thickness is preferably 300 μm, and is formed from a photocurable resin or a film-like resin. Note that the thin film protective layer may be provided on the recording layer via an intermediate layer, an adhesive layer, and the like. The intermediate layer is provided for improving the storage stability of the recording layer and improving the adhesion between the recording layer and the thin film protective layer. As a material used for the intermediate layer, for example, SiO, SiO ₂ , MgF ₂ ,
Examples include inorganic substances such as SnO ₂ and Si ₃ N ₄ . Further, this intermediate layer can be formed by vacuum film formation such as evaporation or sputtering. It is preferable to use an adhesive containing a photocurable resin for the adhesive layer. For example,
After preparing a coating solution by dissolving the photocurable resin as it is or in a suitable solvent, apply the coating solution on the intermediate layer,
By laminating a resin film obtained by, for example, plastic extrusion on the coating film, and curing the coating film by irradiating light from above the laminated resin film,
A resin film can be adhered on the intermediate layer. Thereby, a thin film protective layer is formed.

[0065]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. Example 1 Exemplified compound (1) was dissolved in methylcyclohexane to obtain a coating solution for forming a recording layer (concentration: 1% by mass). Spiral pre-groove (track pitch: 0.4 μm, groove width: 0.2 μ)
m, groove depth: 0.08 μm) formed by injection molding a polycarbonate substrate (diameter: 120 mm,
The pre-groove side surface (thickness: 0.6 mm) was applied by spin coating to form a recording layer (thickness (within the pre-groove): about 80 nm). Next, a light reflecting layer having a thickness of about 100 nm was formed by sputtering silver on the recording layer. Further, a UV curable resin (SD31) is provided on the light reflecting layer.
8. Dainippon Ink and Chemicals, Inc.) was applied and cured by irradiating ultraviolet rays to form a protective layer having a thickness of 7 μm.
The optical disk according to the present invention was obtained through the above steps.

[Examples 2 to 8] The present invention was carried out in the same manner as in Example 1, except that the exemplified compound (1) was changed to the compounds shown in Table 2 (the amount used was not changed). An optical disk was manufactured.

[Comparative Examples 1] to [Comparative Example 5] In Example 1, Exemplified Compound (1) was replaced with Comparative Dye Compound A shown below.
To E (the amount used is not changed),
An optical disc for comparison was produced in the same manner except that the optical disc was changed to 3,3-tetrafluoropropanol.

[0068]

Embedded image

[Evaluation as Optical Disk] A 14T-EFM signal was recorded on the manufactured optical disk at a linear velocity of 3.5 m / sec using a blue-violet semiconductor laser having an oscillation wavelength of 405 nm, and the recorded signal was reproduced. The modulation, groove reflectivity, and sensitivity at optimal power were measured. Recording and recording characteristic evaluation were performed using "DDU1000" manufactured by Pulstec. Table 2 shows the evaluation results.

[0070]

[Table 2]

From the results in Table 2, it can be seen that the optical discs of the present invention (Examples 1 to 8) containing a predetermined azole compound as a recording substance in the recording layer (Comparative Compounds A to E) as the recording substance
Laser light (blue-violet laser light) having a wavelength as short as 405 nm as compared with optical discs containing Comparative Example 1 in the recording layer (Comparative Examples 1 to 5).
It can be seen that a high reflectance is exhibited, a high degree of modulation is provided, and the sensitivity is high. Therefore, the optical information recording medium according to the present invention is capable of recording and reproducing information by irradiating laser light having a wavelength as short as 405 nm, and 405n.
It can be seen that the recording medium has excellent recording characteristics with respect to laser light having a wavelength as short as m.

[0072]

The optical information recording medium of the present invention has a wavelength of 550.
It is possible to record and reproduce information by irradiating a laser beam having a wavelength of not more than nm and shorter than a laser beam used for recording and reproducing information on a CD-R or a DVD-R, particularly a laser beam having a wavelength of 450 nm or less. In addition, the present invention has the effect of exhibiting high reflectance to these laser beams, providing a high degree of modulation, and having high sensitivity and excellent recording characteristics. According to the information recording method of the present invention, by using the optical information recording medium of the present invention, a laser having a wavelength of 550 nm or less and a shorter wavelength than a laser beam used for recording and reproducing information on a CD-R or DVD-R. By irradiating light, in particular, a laser beam having a wavelength of 450 nm or less, it is possible to record information at a high density and record a large amount of information.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09B 23/00 C09B 23/00 J 57/00 F 57/00 Z V B41M 5/26 Y F term (reference) 2H111 EA03 EA12 EA22 EA25 EA32 EA43 FA01 FA12 FA14 FB42 4H056 CA03 CC02 CE02 CE03 DA02 DB15 DC01 DD06 DD19 DD23 DE02 DE11 EA14 EA16 FA06 5D029 JA04 LA11 MA13 WB11 5D090 AA01 BB03 CC01 DD01 EE01

Claims (11)

[Claims] An optical information recording medium having a recording layer on a substrate on which information can be recorded by irradiating a laser beam, wherein the recording layer contains an azole compound represented by the following general formula (I). An optical information recording medium characterized by the above-mentioned. Embedded image [Wherein, A ¹ and A ² each independently represent an azolyl group which may have a substituent, and n represents an integer of 1 to 5. L ¹
Represents an n + 1-valent π-electron conjugated linking group. m is 0 or 1
Where m is 0 and n is 1. A ¹ and A ² may be the same or different. n a plurality of A ² between the time an integer of 2 or more may be different may be identical to one another. A ¹ and L ¹ , A ² and L ¹ , or A ¹ and A ² may be bonded to each other to form a ring. ] 2. In the general formula (I), the azolyl groups represented by A ¹ and A ² are each independently an oxazolyl group,
The optical information recording medium according to claim 1, which is a thiazolyl group or an imidazolyl group. 3. The optical information according to claim 1, wherein in Formula (I), the azolyl groups represented by A ¹ and A ² are each independently a benzoxazolyl group, a benzothiazolyl group, or a benzimidazolyl group. recoding media. 4. The optical information recording medium according to claim 1, wherein m is 1 in the general formula (I). 5. The optical information recording medium according to claim 1, wherein n is 1 in the general formula (I). 6. The π-electron conjugated linking group represented by L ¹ is-(CH = CH) _k- (k: an integer of 1 to 3),-
(C≡C) _h- (h: an integer from 1 to 3), an arylene group, and a linking group selected from the group consisting of heteroarylene groups, or a combination of two or more linking groups selected from these groups 6. A linking group which can be formed by
The optical information recording medium according to any one of the above items. 7. The optical information according to claim 1, wherein the azole compound represented by the general formula (I) is a compound represented by the following general formula (IA). recoding media. Embedded image [Wherein, X and Y are each independently -O-, -NR ^1-
Or -S-, R ¹ represents an alkyl group, an aryl group, or a heterocyclic group, and L ² represents a divalent π-electron conjugated linking group. R ² and R ³ each independently represent a substituent,
s and t represent the integer of 0-4. When s is an integer of 2 or more, a plurality of R ^{2 s} may be the same or different, and may combine with each other to form a ring. When t is an integer of 2 or more, a plurality of R ^{3 s} may be the same or different, and may combine with each other to form a ring. ] 8. The π-electron conjugated linking group represented by L ² may be-(CH = CH) _k- (k: an integer of 1 to 3),-
(C≡C) _h- (h: an integer from 1 to 3), an arylene group, and a linking group selected from the group consisting of heteroarylene groups, or a combination of two or more linking groups selected from these groups 8. A linking group which can be obtained by the following method.
The optical information recording medium according to any one of the above items. 9. The substrate according to claim 1, wherein one of the surfaces has a thickness of 0.2 to 0.2.
9. A transparent disc-shaped substrate having a pre-groove formed at a track pitch of 0.8 [mu] m, wherein the recording layer is provided on a surface of the substrate on which the pre-groove is formed. Item 2. The optical information recording medium according to Item 1. 10. The optical information recording medium according to claim 1, further comprising a light reflecting layer and / or a protective layer made of a metal. 11. An information recording method for recording information by irradiating the optical information recording medium according to claim 1 with a laser having a wavelength of 550 nm or less.