JP4160998B2 - Optical information recording / reproducing method - Google Patents

Description

The present invention relates to an optical information recording / reproducing method, and more particularly to an optical information recording / reproducing method using an optical information recording medium capable of recording and reproducing information by irradiation with a laser beam. In particular, the present invention relates to an optical information recording / reproducing method using a heat mode type optical information recording medium suitable for recording information by irradiation with a short wavelength laser beam having a wavelength of 450 nm or less.

  2. Description of the Related Art Conventionally, an optical information recording medium (optical disc) capable of recording information only once with a laser beam is known. This optical disk is also called a recordable CD (so-called CD-R), and its typical structure is a recording layer made of an organic dye on a transparent disk-shaped substrate, a light reflecting layer made of a metal such as gold, and a resin. The protective layers made of the layers are laminated in this order. Information recording on this CD-R is performed by irradiating the CD-R with a near-infrared laser beam (usually a laser beam having a wavelength of around 780 nm), and the irradiated portion of the recording layer emits the light. Information is recorded by absorbing and locally increasing the temperature, and changing the optical characteristics of the portion due to physical or chemical changes (for example, generation of pits). On the other hand, information reading (reproduction) is also performed by irradiating the CD-R with laser light having the same wavelength as that of the recording laser light, and the optical characteristics of the recording layer change (recording portion). This is done by detecting a difference in reflectance from a non-recorded part (unrecorded part).

  In recent years, an optical information recording medium having a higher recording density has been demanded. In response to such a demand, an optical disk called a write-once digital versatile disk (so-called DVD-R) has been proposed (for example, “Nikkei New Media”, separate volume “DVD”, published in 1995). This DVD-R has a transparent disk shape in which a guide groove (pre-groove) for tracking of the irradiated laser beam is formed with a narrow groove width that is less than half of the CD-R (0.74 to 0.8 μm). Ordinarily, a disc having a recording layer containing an organic dye, a light reflecting layer, and a protective layer laminated in this order and bonded together with the recording layer inside, or a disc having the same shape as this disc And a protective substrate with a recording layer inside. Recording and reproduction of information on this DVD-R is performed by irradiating with visible laser light (usually laser light having a wavelength in the range of 630 nm to 680 nm), which has a higher density than CD-R. Recording is possible.

  Recently, networks such as the Internet and high-definition TV are rapidly spreading. Also, the start of HDTV (High Definition Television) is coming up soon. Under such circumstances, a large-capacity recording medium capable of recording image information inexpensively and simply is required. DVD-R plays a role as a large-capacity recording medium at present, but the demand for larger capacity and higher density is increasing, and development of a recording medium that can meet these demands is also necessary. . For this reason, development of a recording medium having a larger capacity capable of performing high-density recording with light having a shorter wavelength than that of the DVD-R is underway.

  For example, in Patent Documents 1 to 15, in an optical information recording medium having a recording layer containing an organic dye, information is recorded by irradiating a laser beam having a wavelength of 530 nm or less from the recording layer side toward the light reflecting layer side. And a recording / reproducing method for performing reproduction is disclosed. In these methods, an optical disc including 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, a naphthalocyanine compound, Information is recorded and reproduced by irradiating blue (wavelength 430 nm, 488 nm) or blue-green (wavelength 515 nm) laser light.

JP-A-4-74690 JP-A-7-304256 JP-A-7-304257 JP-A-8-127174 Japanese Patent Laid-Open No. 11-53758 JP-A-11-334204 JP 11-334205 A Japanese Patent Laid-Open No. 11-334206 JP 11-334207 A JP 2000-43423 A JP 2000-108513 A JP 2000-113504 A JP 2000-149320 A JP 2000-158818 A JP 2000-228028 A

  However, according to the study by the present inventor, the optical disk described in the above publication can obtain the sensitivity required for practical use when recording information by irradiation with a short wavelength laser beam having a wavelength of 450 nm or less. In addition, it was found that other recording characteristics such as reflectance and modulation are not satisfactory and further improvement is required. In particular, in the optical disk described in the above publication, recording characteristics deteriorated when irradiated with laser light having a wavelength of 450 nm or less.

The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to irradiate information by irradiating laser light having a short wavelength of 450 nm or less, particularly laser light having a wavelength of about 405 nm having high versatility. high-density recording and reproducing are possible, and excellent recording characteristics to provide a resultant Ruhikarijo information recording reproducing method.

In order to achieve the above object, the present inventors have conceived the following present invention.
That is, the present invention records information with a laser beam having a wavelength of 390 to 415 nm on an optical information recording medium having a single recording layer containing a phthalocyanine dye represented by the following general formula (I) on a substrate. In addition, an optical information recording / reproducing method is characterized in that information is reproduced by irradiation with a laser beam having the same wavelength as the laser beam used for recording information.

[Wherein, R represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, or the number of carbon atoms. Represents a sulfamoyl group of 0 to 32, or a halogen atom, n represents an integer of 1 to 8, and when n is an integer of 2 or more, a plurality of Rs may be the same or different from each other; Represents a metal having a hydrogen atom, a metal, a metal oxide, or a ligand. ]

In the general formula (I), M is preferably copper, nickel, iron, cobalt, palladium, magnesium, aluminum, zinc, or silicon.
In the general formula (I), the substituent R is an alkyl group having 3 to 16 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 3 to 16 carbon atoms, or 6 to 6 carbon atoms. 10 is an aryloxy group, or a sulfamoyl group having 2 to 20 carbon atoms, and the substituent R is an alkoxy group having 4 to 12 carbon atoms or a sulfamoyl group having 4 to 16 carbon atoms. It is particularly preferred.
In addition, in the general formula (I), n is preferably an integer of 1 to 4.

In the present invention, the substrate in the optical information recording medium preferably has a pregroove of 0.27 to 0.40 μm on the surface on which the recording layer is formed.
The optical information recording medium preferably further has a light reflecting layer adjacent to the recording layer.

The optical information recording medium used in the present invention has a recording layer containing a phthalocyanine dye represented by the general formula (I) on a substrate. This phthalocyanine dye has a main absorption band near 700 nm and a sub-absorption band near 340 nm. By using this phthalocyanine dye as a recording material for the recording layer, it has high sensitivity to short wavelength lasers with a wavelength of 450 nm or less, high reflectivity, and good recording and reproduction characteristics that give a high degree of modulation. An optical information recording medium.
Therefore, in the present invention, a method for recording and reproducing information by irradiating the above-described optical information recording medium with laser light having a wavelength of 450 nm or less is applied.

The optical information recording / reproducing method of the present invention uses a phthalocyanine dye represented by the above general formula (I) as a recording material for a recording layer, so that a laser beam with a short wavelength of 450 nm or less, particularly a highly versatile wavelength of 405 nm is used. There is an effect that high-density recording and reproduction of information can be performed by irradiating a laser beam in the vicinity, and good recording and reproduction characteristics such as high sensitivity, high reflectance, and high degree of modulation can be obtained. That is, it is possible to record information at a higher density than conventional CD-R and DVD-R, and it is possible to record information of a larger capacity.

Hereinafter, embodiments of the optical information recording / reproducing method of the present invention will be described in detail.

The optical information recording / reproducing method of the present invention is characterized by using an optical information recording medium having a recording layer containing a phthalocyanine dye represented by the following general formula (I) on a substrate.

[Wherein, R represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, or the number of carbon atoms. Represents a sulfamoyl group of 0 to 32, or a halogen atom, n represents an integer of 1 to 8, and when n is an integer of 2 or more, a plurality of Rs may be the same or different from each other; Represents a metal having a hydrogen atom, a metal, a metal oxide, or a ligand. ]

  In the general formula (I), preferred examples of the substituent represented by R include an alkyl group having 3 to 16 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 3 to 16 carbon atoms, An aryloxy group having 6 to 10 carbon atoms or a sulfamoyl group having 2 to 20 carbon atoms can be given.

  More preferred examples of the substituent represented by R include an alkoxy group having 4 to 12 carbon atoms or a sulfamoyl group having 4 to 16 carbon atoms. Particularly preferred is a sulfamoyl group having 6 to 12 carbon atoms.

  In the general formula (I), the substituent R may further have a substituent, and examples of the substituent include those described below.

  A linear 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), aralkyl groups having 7 to 18 carbon atoms (for example, benzyl, anisyl), alkenyl groups having 2 to 20 carbon atoms (for example, vinyl, 2-methylvinyl), 2 to 2 carbon atoms 20 alkynyl groups (eg, ethynyl, 2-methylethynyl, 2-phenylethynyl), halogen atoms (eg, F, Cl, Br, I), cyano groups, hydroxyl groups, carboxyl groups, 2 to 20 carbon atoms An acyl group (eg, acetyl, benzoyl, salicyloyl, pivaloyl), an alkoxy group having 1 to 20 carbon atoms (eg, Xy, butoxy, cyclohexyloxy), aryloxy groups having 6 to 20 carbon atoms (for example, phenoxy, 1-naphthoxy, toluoyl), alkylthio groups having 1 to 20 carbon atoms (for example, methylthio, butylthio, benzylthio, 3- Methoxypropylthio), arylthio groups having 6 to 20 carbon atoms (for example, phenylthio, 4-chlorophenylthio), alkylsulfonyl groups having 1 to 20 carbon atoms (for example, methanesulfonyl, butanesulfonyl), 6 to 6 carbon atoms 20 arylsulfonyl groups (for example, benzenesulfonyl, paratoluenesulfonyl), carbamoyl groups having 1 to 17 carbon atoms (for example, unsubstituted carbamoyl, methylcarbamoyl, ethylcarbamoyl, n-butylcarbamoyl, dimethylcarbamoyl), carbon Amide groups having 1 to 16 atoms (eg, acetamide, benzamide), acyloxy groups having 2 to 10 carbon atoms (eg, acetoxy, benzoyloxy), alkoxycarbonyl groups having 2 to 10 carbon atoms (eg, methoxycarbonyl, Ethoxycarbonyl), 5- or 6-membered heterocyclic group (for example, aromatic heterocycles such as pyridyl, thienyl, furyl, thiazolyl, imidazolyl, pyrazolyl, pyrrolidine ring, piperidine ring, morpholine ring, pyran ring, thiopyran ring, dioxane ring , Heterocycles such as dithiolane rings).

  In the general formula (I), the preferred substituent for the substituent R is a linear or cyclic alkyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms, or a 7 to 15 carbon atom. Aralkyl group, alkoxy group having 1 to 16 carbon atoms, aryloxy group having 6 to 14 carbon atoms, halogen atom, alkoxycarbonyl group having 2 to 17 carbon atoms, carbamoyl group having 1 to 10 carbon atoms, carbon number Among them, an amide group having 1 to 10 carbon atoms, preferably a linear or cyclic alkyl group having 1 to 10 carbon atoms, an aralkyl group having 7 to 13 carbon atoms, an aryl group having 6 to 10 carbon atoms, carbon An alkoxy group having 1 to 10 atoms, an aryloxy group having 6 to 10 carbon atoms, a chlorine atom, an alkoxycarbonyl group having 2 to 11 carbon atoms, and a carbamoyl group having 1 to 7 carbon atoms An amide group having 1 to 8 carbon atoms, particularly preferred is a branched or cyclic alkyl group having 3 to 10 carbon atoms, an aralkyl group having 7 to 11 carbon atoms, or an alkoxy having 1 to 8 carbon atoms. Groups, alkoxycarbonyl groups of 3 to 9 carbon atoms, phenyl and chlorine atoms.

  In general formula (I), n is preferably 2 to 6, more preferably 3 or 4, and particularly preferably 4. When n is an integer of 2 or more, a plurality of Rs may be the same or different from each other, but are preferably the same. In the general formula (I), M is preferably a metal, of which copper, nickel or palladium is preferred, copper or nickel is more preferred, and copper is particularly preferred.

  The compound represented by the general formula (I) may be bonded at an arbitrary position to form a multimer, and in this case, each unit may be the same as or different from each other, and polystyrene, polymethacrylate, You may couple | bond with polymer chains, such as polyvinyl alcohol and a cellulose.

  The phthalocyanine dye represented by the general formula (I) used in the optical information recording medium of the present invention may be used alone, or may be used by mixing a plurality of types having different structures. Is preferably used. The phthalocyanine dye represented by the general formula (I) inevitably contains substitution position isomers of the substituent R at the time of synthesis, but these substitution position isomers are not distinguished from each other and are the same dye. Can be considered. Further, even when isomers are included in the substituent of R, they can be regarded as the same phthalocyanine dye without distinguishing them. Accordingly, the case where the structures are different is either when the constituent atom type or number of the substituent R is different or when n is different, as described in the general formula (I).

  The recording layer of the optical information recording medium in the present invention forms recording marks (pits) by absorbing the energy of laser light used for recording and chemically or physically decomposing and altering it. This recording mark is detected as a portion where the reflectance has changed during reproduction. The extinction coefficient (k) is an optical property related to the amount of light energy absorbed, and is not only related to the amount of laser light energy absorbed by the recording layer during recording, but also to the reflectance detected during recording and reproduction. Is involved. The refractive index (n) is related to the optical size of the recording mark (amount of change in reflection quality). Since the output of laser light used for recording is in the practical range of several mW to several tens of mW, the extinction coefficient (k) and refractive index (n) correspond to the basic skeleton of the compound used for the recording layer. There is a preferred range of

  In the case of the recording layer of the optical information recording medium in the present invention, the refractive index (n) and extinction coefficient (k) of the recording layer containing the compound represented by the general formula (I) are the laser used for recording. The light wavelength is preferably in the range of 1.0 <n <1.9 and 0.03 <k <0.30, and further 1.5 <n <1.9 and 0.04 <k <0. More preferably, it is in the range of .15. The refractive index (n) and extinction coefficient (k) can be easily measured by, for example, a rotational analyzer method (ellipsometry).

  Hereinafter, preferred specific examples of the phthalocyanine dye used in the present invention can be appropriately selected from the following Table 1, but the present invention is not limited thereto. In addition, the number of the substitution position of the substituent R of a phthalocyanine dye is shown below.

  Examples of the phthalocyanine dye used in the present invention include “Phthalocyanine—Chemistry and Function” (P. 1-62), C.I. C. Leznoff-A. B. P. It can be synthesized by the method described in Lever co-authored by VCH, published by Phthalocyanines-Properties and Applications (P. 1-54), the cited method, or similar methods.

  The optical information recording medium in the present invention is not particularly limited as long as it has a recording layer containing the phthalocyanine dye on a substrate, and can be applied to optical information recording media having various configurations. The optical information recording medium in the present invention can be configured to have a recording layer, a light reflecting layer, and a protective layer in this order on a disc-like substrate on which pregrooves having a constant track pitch are formed, for example. Hereinafter, taking an optical information recording medium having a recording layer, a light reflecting layer, and a protective layer in this order on a disk-like substrate as an example, the configuration of the optical information recording medium will be described in detail according to the manufacturing process.

  The substrate of the optical information recording medium in the present invention can be arbitrarily selected from various materials used as a substrate of a conventional optical information recording medium. Examples of the substrate material include acrylic resins such as glass, polycarbonate and polymethyl methacrylate, vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers, epoxy resins, amorphous polyolefins and polyesters. You may use them together. These materials can be used as a film or as a rigid substrate. Among the above materials, polycarbonate is preferable from the viewpoints of moisture resistance, dimensional stability, price, and the like.

  In the optical information recording medium of the present invention, it is preferable to use a substrate on which a pre-groove having a narrower track pitch is formed as compared with CD-R and DVD-R in order to achieve higher recording density. In the case of the optical information recording medium in the present invention, the track pitch is preferably in the range of 0.2 to 0.8 μm, more preferably in the range of 0.2 to 0.5 μm, and 0.27 to 0. It is particularly preferable that the thickness is in the range of 40 μm.

  A subbing layer may be provided on the surface of the substrate on which the recording layer is provided for the purpose of improving the flatness, improving the adhesive force, and preventing the recording layer from being altered. Examples of the material for the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, chlorosulfonated. High molecular substances such as polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate; 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 this 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 can be formed by a method such as vapor deposition, sputtering, CVD or solvent coating, but solvent coating is preferred. In the case of forming a recording layer by solvent coating, in addition to the phthalocyanine dye, if necessary, a quencher, a binder or the like is dissolved in a solvent to prepare a coating solution, and then this coating solution is applied to the substrate surface to form a coating film. After forming, the formed coating film is dried. Examples of the solvent of 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; dimethylformamide and the like Amides; Hydrocarbons such as methylcyclohexane; Ethers such as dibutyl ether, diethyl ether, tetrahydrofuran, dioxane; Alcohols such as ethanol, n-propanol, isopropanol, n-butanol, diacetone alcohol; 2,2,3,3-tetra Fluorinated solvents such as fluoropropanol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, etc. And the like can be mentioned recall ethers. The above 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 depending on the purpose.

  When a binder is used, examples of the binder include natural organic polymer materials such as gelatin, cellulose derivatives, dextran, rosin, and rubber; and hydrocarbon resins such as polyethylene, polypropylene, polystyrene, and polyisobutylene; Vinyl resins such as vinyl chloride, polyvinylidene chloride, polyvinyl chloride / polyvinyl acetate copolymer, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resin, butyral resin, Examples include synthetic organic polymers such as rubber derivatives and initial condensates of thermosetting resins such as phenol / formaldehyde resins. When a binder is used in combination as a material for the recording layer, the amount of binder used is generally in the range of 0.01 to 50 times (mass ratio), preferably 0.1 times the amount of the dye. It is in the range of ˜5 times amount (mass ratio). Thus, the density | concentration of the pigment | dye in the coating liquid prepared is in the range of 0.01-10 mass% generally, Preferably it exists in the range of 0.1-5 mass%.

  Examples of the coating method include a spray method, a spin coating method, a dip 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 in the range of 20 to 500 nm.

  The recording layer can contain various anti-fading agents in order to improve the light resistance of the recording layer. As the antifading agent, a singlet oxygen quencher is generally used. As the singlet oxygen quencher, those described in publications such as known patent specifications can be used. Specific examples thereof include JP-A Nos. 58-175893, 59-81194, 60-18387, 60-19586, 60-19586, 60-35054, 60-36190, 60-36191, 60-44554, 60-44555, 60-44389, 60-44390, 60-54892, 60-47069, 63-20995, JP Listed in publications such as Nos. 4-25492, 1-38680, and 6-26028, German Patent No. 350399, and the Chemical Society of Japan, October 1992, page 1141 Can do. Examples of preferable singlet oxygen quenchers include compounds represented by the following general formula (II).

(However, R ²¹ represents an alkyl group which may have a substituent, and Q ⁻ represents an anion.)
In the general formula (II), R ²¹ is generally an optionally substituted alkyl group having 1 to 8 carbon atoms, and is preferably an unsubstituted alkyl group having 1 to 6 carbon atoms. Examples of the substituent for the alkyl group include a halogen atom (eg, F, Cl), an alkoxy group (eg, methoxy, ethoxy), an alkylthio group (eg, methylthio, ethylthio), an acyl group (eg, acetyl, propionyl), an 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, and an alkoxycarbonyl group are preferable. Preferred examples of the Q ⁻ anion include ClO ₄ ⁻ , AsF ₆ ⁻ , BF ₄ ⁻ , and SbF ₆ ⁻ .

  Examples of compounds represented by the general formula (II) are shown in Table 2.

  The use amount of the antifading agent such as the singlet oxygen quencher is usually in the range of 0.1 to 50% by weight, preferably in the range of 0.5 to 45% by weight, based on the amount of the dye. Preferably, it is the range of 3-40 mass%, Most preferably, it is the range of 5-25 mass%.

  It is preferable to provide a light reflection layer adjacent to the recording layer for the purpose of improving reflectivity during information reproduction. The light reflecting material that is a material of the light reflecting layer is a material having a high reflectivity with respect to the laser. Examples thereof include Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W. , Mn, Re, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, Ge, Te, Pb, Po, Sn, Bi And metals such as metals and metalloids or stainless steel. These substances may be used alone or in combination of two or more or as an alloy. Among these, Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel are preferable. Particularly preferred are Au metal, Ag metal, Al metal or alloys thereof, and most preferred are Ag metal, Al metal or alloys thereof. The light reflecting layer can be formed on the substrate or the recording layer, for example, by vapor deposition, sputtering or ion plating of the light reflecting material. The layer thickness of the light reflecting layer is generally in the range of 10 to 300 nm, and preferably in the range of 50 to 200 nm.

A protective layer is preferably provided 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 case of adopting the same form as in the case of manufacturing a DVD-R type optical information recording medium, that is, a structure in which two substrates are laminated with the recording layer inside, the protective layer is not necessarily provided. Examples of materials used for the protective layer include inorganic substances such as ZnS—SiO ₂ , ZnS, SiO, SiO ₂ , MgF ₂ , SnO ₂ , and Si ₃ N ₄ , thermoplastic resins, thermosetting resins, and UV curable resins. Organic substances such as resins can be mentioned. The protective layer can be formed, for example, by laminating a film obtained by extrusion of plastic on the reflective layer via an adhesive. Or you may provide by methods, such as vacuum evaporation, sputtering, and application | coating. In the case of a thermoplastic resin or a thermosetting resin, it can also be formed by dissolving these in a suitable solvent to prepare a coating solution, and then applying and drying the coating solution. 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 a suitable solvent, coating the coating solution, and curing it by irradiating with UV light. In these coating liquids, various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added according to the purpose. The thickness of the protective layer is generally in the range of 0.1 μm to 1 mm. Through the above steps, a recording layer, a light reflecting layer, and a protective layer on a substrate, or a laminate in which a light reflecting layer, a recording layer, and a protective layer are provided on a substrate can be manufactured.

The information recording / reproducing method of the present invention is performed, for example, as follows using the optical information recording medium. First, recording light such as a semiconductor laser is irradiated from the substrate side or the protective layer side while rotating the optical information recording medium at a constant linear velocity or a constant angular velocity. By this light irradiation, the recording layer absorbs the light and the temperature rises locally, causing a physical or chemical change (for example, generation of pits) and changing its optical characteristics, thereby recording information. It is thought that it is done. In the present invention, a blue-violet semiconductor laser having an oscillation wavelength in the range of 390 to 415 nm is used as the recording light source .

  The information recorded as described above is reproduced by irradiating a laser beam from the substrate side while rotating the optical information recording medium at the same constant linear velocity as described above and detecting the reflected light. Can do.

  As in the conventional DVD-R, the optical information recording medium according to the present invention comprises two recording layers and a light reflecting layer provided on a transparent disk-like substrate on which pregrooves having a constant track pitch are formed. The laminated body can have a structure in which the respective recording layers are bonded to each other. Moreover, it is good also as a structure which bonded together the disk shaped protective substrate of the same shape as this laminated body with a recording layer inside. In the case of a bonded structure, for example, a transparent substrate having a diameter of 120 ± 3 mm and a thickness of 0.6 ± 0.1 mm is used, and the thickness of the optical information recording medium after bonding is 1.2 ±. 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. It can also be bonded with double-sided tape.

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

The thin film protective layer preferably has a thickness of 0.1 to 300 μm, and is formed from a photocurable resin or a film-like resin. The thin film protective layer may be provided on the recording layer via an intermediate layer or an adhesive layer. The intermediate layer is provided in order to improve the storage stability of the recording layer and improve the adhesion between the recording layer and the thin film protective layer. Examples of the material used for the intermediate layer include inorganic substances such as ZnS—SiO ₂ , ZnS, SiO, SiO ₂ , MgF ₂ , SnO ₂ , and Si ₃ N ₄ . The intermediate layer can be formed by vacuum film formation such as vapor deposition or sputtering. It is preferable to use an adhesive containing a photocurable resin or an acrylic pressure-sensitive adhesive for the adhesive layer. For example, after preparing a coating solution by dissolving the photocurable resin as it is or in an appropriate solvent, this coating solution is applied onto the intermediate layer, and a resin film obtained by, for example, plastic extrusion is applied onto the coating film. The resin film can be adhered onto the intermediate layer by laminating and curing the coating film by light irradiation from above the laminated resin film. Thereby, a thin film protective layer is formed.

Further, in the present invention, by using a phthalocyanine dye as a recording material for the recording layer, it is used for a short wavelength laser beam having a wavelength of 450 nm or less and a conventional CD-R without using a different recording material for each different wavelength. Recording and reproduction by both laser beams having a wavelength of 750 to 850 nm can be made possible. That is, the optical information recording medium in the present invention is a highly versatile optical information recording medium, and an information recording / reproducing method can be simply provided by using the optical information recording medium.

  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to a following example.

[Example 1]
The exemplified compound (I-1) was dissolved in methylcyclohexane to obtain a recording layer forming coating solution (concentration: 1% by mass). A polycarbonate substrate (diameter: 120 mm, thickness) on which a spiral pre-groove (track pitch: 0.4 μm, groove width: 0.2 μm, groove depth: 0.08 μm) is formed on the surface of this coating solution by injection molding. The recording layer (thickness (inside the pregroove): about 80 nm) was formed on the surface of the pregroove side having a thickness of 0.6 mm by spin coating. Next, silver was sputtered on the recording layer to form a light reflecting layer having a thickness of about 100 nm. Further, a UV curable resin (trade name: SD318, manufactured by Dainippon Ink & Chemicals, Incorporated) was applied on the light reflecting layer and cured by irradiating with ultraviolet rays to form a protective layer having a layer thickness of 7 μm. The optical disc according to the present invention was obtained through the above steps.

[Example 2] to [Example 7]
An optical disk according to the present invention was produced in the same manner as in Example 1 except that the exemplified compound (I-1) was changed to the compounds shown in Table 3 (the amount used was not changed).

[Comparative Example 1] to [Comparative Example 7]
For comparison, in the same manner as in Example 1 except that the above exemplary compound (I-1) was replaced with the comparative dye compounds A to G shown below (the amount used was not changed) (the amount used was not changed). The optical disc was manufactured.

[Evaluation as optical disc 1]
A 14T-EFM signal was recorded on the produced 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 degree of modulation, groove reflectivity, and sensitivity at the optimum power were measured. Recording and recording characteristic evaluation were performed using “DDU1000” manufactured by Pulstec. The evaluation results are shown in Table 3.

  From the results of Table 3, optical disks having recording layers containing phthalocyanine dyes (Examples 1 to 7), which are features of the present invention, are optical disks having recording layers containing comparative compounds A to G (Comparative Examples 1 to 7). As compared with the above, it can be seen that the laser beam having a wavelength of 405 nm exhibits a high reflectance, gives a high degree of modulation, and is highly sensitive. Therefore, it can be seen that high recording characteristics can be obtained by irradiating the optical disk using the phthalocyanine dye according to the present invention with a laser beam having a wavelength of 405 nm.

Claims (7)

On an optical information recording medium having a single recording layer containing a phthalocyanine dye represented by the following general formula (I) on a substrate, information is recorded with a laser beam having a wavelength of 390 to 415 nm, An optical information recording / reproducing method comprising reproducing information by irradiation with a laser beam having the same wavelength as the laser beam used for recording.
[Chemical formula 1]

[Wherein, R represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, or the number of carbon atoms. Represents a sulfamoyl group of 0 to 32, or a halogen atom, n represents an integer of 1 to 8, and when n is an integer of 2 or more, a plurality of Rs may be the same or different from each other; Represents a metal having a hydrogen atom, a metal, a metal oxide, or a ligand. ]   The optical information recording / reproducing method according to claim 1, wherein M in the general formula (I) is copper, nickel, iron, cobalt, palladium, magnesium, aluminum, zinc, or silicon.   R in the general formula (I) is an alkyl group having 3 to 16 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 3 to 16 carbon atoms, or an aryloxy group having 6 to 10 carbon atoms. The optical information recording / reproducing method according to claim 1, wherein the optical information recording / reproducing method is a sulfamoyl group having 2 to 20 carbon atoms.   3. The optical information recording / reproducing method according to claim 1, wherein R in the general formula (I) is an alkoxy group having 4 to 12 carbon atoms or a sulfamoyl group having 4 to 16 carbon atoms.   The optical information recording / reproducing method according to any one of claims 1 to 4, wherein n is an integer of 1 to 4.   6. The substrate according to claim 1, wherein the substrate in the optical information recording medium has a track pitch of 0.27 to 0.40 [mu] m on the surface on which the recording layer is formed. The optical information recording / reproducing method described.   7. The optical information recording / reproducing method according to claim 1, wherein the optical information recording medium further includes a light reflecting layer adjacent to the recording layer.