JP2003039830A - Optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information recording medium which can record and reproduce in high density information by irradiating with a laser beam having a short wavelength of a wavelength of 440 nm or less and which has excellent recording characteristics. SOLUTION: The optical information recording medium comprises an amorphous recording layer capable of recording information by irradiating with the laser beam having the wavelength of 440 nm or less on a substrate. In this medium, the recording layer gas at least one absorption maximum in a short wavelength region of the laser beam wavelength or less, and a wavelength (λm ) of the absorption maximum of the longest wavelength is in a range of 340 to 400 nm.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium capable of recording and reproducing information using a laser beam. In particular, the present invention relates to a heat mode type optical information recording medium suitable for recording information using a short wavelength laser beam having a wavelength of 440 nm or less. Conventionally, an optical information recording medium (optical disk) capable of recording information only once by laser light is known. This optical disc is a recordable CD (so-called CD).
-R), and its typical structure is that a recording layer made of an organic dye, a light reflecting layer made of metal such as gold, and a protective layer made of resin are laminated in this order on a transparent disk-shaped substrate. Is provided. 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 near 780 nm), and the irradiated portion of the recording layer emits the light. Information is recorded by absorbing and locally raising the temperature, causing a physical or chemical change (eg, pit generation) and changing its optical properties. On the other hand, reading (reproduction) of information is also performed by irradiating laser light having the same wavelength as the recording laser light, and the part where the optical characteristics of the recording layer have changed (recorded part) and the part that has not changed (unrecorded) Information is reproduced by detecting the difference in reflectance from (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 disc called a recordable digital vasatile disc (so-called DVD-R) has been proposed (for example, “Nikkei New Media”, separate volume “DVD”, published in 1995).
This DVD-R is a transparent disk-shaped substrate in which the guide groove (pre-groove) for tracking the irradiated laser beam is narrower than half of the CD-R (0.74-0.8 μm). On top of the recording layer made of a dye, and usually two light reflecting layers on the recording layer, and further a protective layer if necessary, or a disk-shaped protective substrate having the same shape as the disk The recording layer has a structure in which the recording layer is bonded inside with an adhesive. Information recording / reproduction on a DVD-R is performed with visible laser light (usually 630n).
(laser light with a wavelength in the range of m to 680 nm) is performed, and higher density recording than CD-R is possible. Recently, networks such as the Internet and high-definition TVs are rapidly spreading. HDT
V (High Definition Televis
ion) will soon be broadcast, and there is an increasing demand for a large-capacity recording medium for recording image information at low cost and in a simple manner. Although the DVD-R is secured to a certain extent as a large-capacity recording medium, it cannot be said that the DVD-R has a large enough recording capacity to meet future requirements.
Therefore, development of an optical disc having a higher recording capacity by improving the recording density by using a laser beam having a wavelength shorter than that of the DVD-R is underway. For example, JP-A-4-74690, JP-A-7-30425
No. 6, JP-A-7-304257, JP-A-8-
127174, 11-53758, 1
1-334204, 11-334205, 11-334206, 11-33420
No. 7, JP 2000-43423 A, No. 200
No. 0-108513, 2000-113504, 2000-149320, 2000-
In 158818 and 2000-228028, an optical information recording medium having a recording layer containing an organic dye has a wavelength of 530 from the recording layer side toward the light reflecting layer side.
A recording / reproducing method for recording / reproducing information by irradiating a laser beam of nm or less is disclosed. Specifically, optical discs using porphyrin compounds, azo dyes, metal azo dyes, quinophthalone dyes, trimethine cyanine dyes, dicyanovinylphenyl skeleton dyes, coumarin compounds, naphthalocyanine compounds, etc., as recording layer dyes. An information recording / reproducing method for recording / reproducing information by irradiating laser light of blue (wavelength 430 nm, 488 nm) or blue-green (wavelength 515 nm) has been proposed. From the viewpoint of compatibility with the current CD-R system, an optical recording medium capable of recording / reproducing with laser beams in two different wavelength regions has been proposed. For example, JP 2000-141900 A, 2000-
158816, 2000-185471, 2000-289342, 2000-3
No. 09165 discloses dyes used for CD-R and D
There has been proposed a recording medium that can be recorded / reproduced by any laser light by mixing with a dye used in VD-R. However, according to the study of the present inventor, in the optical disk described in the above publication, when information is recorded by irradiation with a short wavelength laser beam having a wavelength of 440 nm or less. Further, it has been found that further improvement is required because the recording characteristics such as sensitivity, reflectance and modulation degree are not satisfactory. In particular, in the optical disk described in the above publication, the recording characteristics deteriorated when a laser beam having a wavelength of about 405 nm was irradiated. The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a laser beam having a short wavelength of 440 nm or less, particularly a highly versatile wavelength 40.
An object of the present invention is to provide an optical information recording medium capable of high-density recording and reproduction of information by irradiating a semiconductor laser beam of around 5 nm and having excellent recording characteristics. In order to achieve the above object, an optical information recording medium of the present invention has a wavelength of 440 n on a substrate.
An optical information recording medium having an amorphous recording layer capable of recording information by irradiation with a laser beam having a short wavelength of m or less, wherein the recording layer has at least one absorption maximum in a short wavelength region of a laser beam wavelength or less. The wavelength is set to 440 by designing the recording layer so that the wavelength (λ _m ) of the longest wave absorption maximum is in the range of 340 to 400 nm.
It is possible to obtain an optical information recording medium having a high sensitivity to a laser beam having a short wavelength of less than or equal to nm and having good recording / reproducing characteristics giving a high reflectance and a high degree of modulation.
Further, the wavelength difference (Δλ) between the λ _m and the corresponding absorption maximum in the chloroform solution of the substance forming the recording layer.
By designing the recording layer so as to be 10 nm or less, a more excellent optical information recording medium can be obtained. The optical information recording medium of the present invention preferably has the following modes. (1) The substance forming the recording layer is a compound selected from a cyanine dye, a hemicyanine dye, an oxonol dye, an azole derivative, a triazine derivative, a 1-aminobutadiene derivative, a cinnamic acid derivative, and a tetraazaporphine derivative. (2) A light reflecting layer made of metal is provided separately from the recording layer. (3) A protective layer is provided separately from the recording layer. (4) The substrate has a track pitch of 0.2-0.
It is a transparent disk-like substrate on which 8 μm pregrooves are formed, and a recording layer is provided on the surface on the side where the pregrooves are formed. Further, the above optical information recording medium has a wavelength of 44.
Information can be recorded by irradiating a laser beam of 0 nm or less. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an optical information recording medium and an information recording method according to the present invention will be described in detail below. The optical information recording medium of the present invention is an optical information recording medium having a recording layer on which information can be recorded by irradiating a laser beam having a wavelength of 440 nm or less on the substrate. The wavelength of the longest absorption maximum (λ _m ) is in the range of 340 to 400 nm. When λ _m is less than 340 nm, the reflectance is high, but the sensitivity is low. When it exceeds 400 nm, the sensitivity is high but the reflectance is low. The λ _m is preferably 340 to 395 nm,
More preferably, it is 345-390 nm. Furthermore, the wavelength difference (Δλ) between λ _m and the corresponding absorption maximum in the chloroform solution of the substance forming the recording layer is preferably 10 nm or less, and 8 nm.
The following is more preferable. The compound used for the optical information recording medium of the present invention is not particularly limited as long as it satisfies the above-mentioned spectral absorption characteristics, but it is a cyanine dye, hemicyanine dye, oxonol dye, azole derivative, triazine derivative, 1-aminobutadiene derivative. Cinnamic acid derivatives and tetraazaporphine derivatives are preferred, and azole derivatives and tetraazaporphine derivatives are particularly preferred. In these compounds, Δλ is 10 nm.
In designing the following, it is important to select the substituent species and their substitution positions. According to the inventor's study,
As the substituent species, it has been found that a branched alkyl group having 3 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, and a hydroxyl group are preferable. Further, as the substitution position of the substituent, it is preferable to substitute at a position as close as possible to the chromophore of the compound correlated with λ _m , the number of atoms separating the chromophore and the substituent is preferably 5 or less, It has been found that it is more preferable that the number is 3 or less. The substituent imparts an electronic perturbation to the chromophore and λ _m
As long as does not deviate from the desired range, it is most preferable that the substituent is directly substituted with a chromophore. Preferred as the cyanine dye used in the optical information recording medium of the present invention is Japanese Patent Application No. 2 filed by the present applicant.
000-48504, which is a compound represented by the general formula (I), and preferred as a hemicyanine dye is
The compounds represented by the general formulas (I), (II), and (III) described in Japanese Patent Application No. 2001-31146 by the present applicant, and preferred as the oxonol dye are JP-A-2001-71638 by the present applicant. The compounds represented by the general formula (I-1) and general formula (I-2) described in the publication and preferred as the azole derivative are those represented by the general formula (I) described in Japanese Patent Application No. 2000-285853 by the present applicant.
And Japanese Patent Application No. 2000 by the present applicant
The compound represented by the general formula (I) described in No. -294241 and preferred as the triazine derivative is a compound represented by the general formula (I) described in Japanese Patent Application No. 2000-95630 by the present applicant, Preferred as the 1-aminobutadiene derivative is Japanese Patent Application No. 1 filed by the present applicant.
A compound represented by the general formula (I) described in JP-A No. 1-254672, and preferred as a cinnamic acid derivative is a compound represented by the general formula (I) described in JP-A-2001-71639 by the present applicant. The preferred tetraazaporphine derivatives are those disclosed in Japanese Patent Application Laid-Open No.
It is a compound represented by the general formula (I) described in JP-A-01-14740. The compound used in the optical information recording medium of the present invention 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. You may couple | bond with polymer chains, such as a polystyrene, polymethacrylate, polyvinyl alcohol, and cellulose. The above-mentioned compound used in the optical information recording medium of the present invention may be used alone as a specific derivative, or a plurality of compounds having different structures may be mixed and used. In the following, preferred specific examples of the compound used in the present invention are listed, but the present invention is not limited thereto. ## STR1 ## ## STR2 ## Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image The optical information recording medium of the present invention has a recording layer containing a compound having the specific spectral absorption characteristic on a substrate. The optical information recording medium of the present invention includes a variety of configurations. The optical information recording medium of the present invention has a configuration in which a recording layer, a light reflecting layer and a protective layer are arranged in this order on a disc-like substrate on which pregrooves having a constant track pitch are formed, or a light reflecting layer and a recording layer on the substrate. A structure having a layer and a protective layer in this order is preferable. In addition, two laminated bodies in which a recording layer and a light reflection layer are provided on a transparent disk-shaped substrate on which pregrooves having a constant track pitch are formed are bonded so that each recording layer is inside. The configuration is also preferable. The optical information recording medium of the present invention has a higher recording density than CD-R and DVD-R in order to achieve higher recording density.
It is possible to use a substrate on which a pre-groove having a narrower track pitch is formed. 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 0.2 to 0.5 μm, particularly 0.27 to It is preferably in the range of 0.40 μm. The depth of the pregroove is
Preferably it is in the range of 0.03-0.18 μm,
Further, it is preferably in the range of 0.05 to 0.15 μm, and particularly preferably in the range of 0.06 to 0.1 μm. As an example of the optical information recording medium of the present invention, a manufacturing method having a recording layer, a light reflecting layer, and a protective layer in this order on a disc-like substrate will be described below. The substrate of the optical information recording medium of 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 viewpoint of moisture resistance, dimensional stability, price, and the like. An undercoat layer may be provided on the surface of the substrate on the side where 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 is formed by vapor deposition, sputtering,
Although it can be performed by a method such as CVD or solvent coating, solvent coating is preferred. In this case, the dye compound,
Further, if desired, a quencher, a binder or the like can be 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 and then dried. 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; and dimethylformamide. 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;
Fluorine solvents such as 2,3,3-tetrafluoropropanol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and the like. 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 hydrocarbons such as polyethylene, polypropylene, polystyrene and polyisobutylene. Resins, polyvinyl chloride, polyvinylidene chloride, vinyl resins such as polyvinyl chloride / polyvinyl acetate copolymers, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resins, Examples thereof include synthetic organic polymers such as butyral resins, 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 the binder used is generally in the range of 0.01 to 50 times (weight ratio) with respect to the dye, preferably 0.8.
The amount is in the range of 1 to 5 times (weight ratio). The concentration of the dye in the coating solution thus prepared is generally 0.01.
-10% by mass, preferably 0.1-5% by 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 generally in the range of 20 to 500 nm, preferably in the range of 30 to 300 nm, more preferably 5
It is in the range of 0 to 100 nm. Various thermal decomposition controlling agents can be added to the recording layer for the purpose of improving the recording characteristics by controlling the thermal decomposition behavior of the recording layer during laser light irradiation. For example,
The method of adding a metal complex described in European Patent No. 0600427 is effective, and among the metal complexes, metallocene derivatives are preferable, and ferrocene derivatives are particularly preferable. 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-58-175.
693, 59-81194, 60-18387
No. 60-19586, No. 60-19587, No. 60-35054, No. 60-36190, No. 60-
No. 36191, No. 60-44554, No. 60-445
55, 60-44389, 60-44390
No. 60-54892, No. 60-47069, No. 63-209995, JP-A-4-25492, JP-B-1-38680, No. 6-26028, etc., German Patent No. 350399 And the one described in the Chemical Society of Japan, October 1992, page 1141 and the like. Examples of preferred singlet oxygen quenchers include compounds represented by the following general formula (II). Embedded image Wherein 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, preferably an unsubstituted alkyl group having 1 to 6 carbon atoms. As the substituent of the alkyl group, a halogen atom (eg, F, Cl),
Alkoxy groups (eg, methoxy, ethoxy), alkylthio groups (eg, methylthio, ethylthio), acyl groups (eg,
Acetyl, propionyl), acyloxy groups (eg, acetoxy, propionyloxy), hydroxy groups, alkoxycarbonyl groups (eg, methoxycarbonyl, ethoxycarbonyl), alkenyl groups (eg, vinyl), aryl groups (eg, phenyl, naphthyl) Can be mentioned.
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 ⁻ , B
F ₄ ⁻ and SbF ₆ ⁻ can be mentioned. Formula (II)
Table 1 shows examples of compounds represented by [Table 1] The amount of the antifading agent such as the singlet oxygen quencher used is usually 0.1 to 50 with respect to the amount of the dye.
The mass range is preferably 0.5 to 45 mass%.
More 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 the reflectance 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 laser light.
g, Se, Y, Ti, Zr, Hf, V, Nb, Ta, C
r, Mo, W, Mn, Re, Fe, Co, Ni, Ru,
Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, C
d, Al, Ga, In, Si, Ge, Te, Pb, P
Examples include metals such as o, Sn, and Bi, metalloids, and stainless steel. These substances may be used alone or in combination of two or more or as an alloy. Of these, preferred are
Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel. Particularly preferably, Au metal, Ag metal,
Al metal or an alloy thereof is most preferable, and Ag metal, Al metal, or an alloy thereof is most preferable.
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 the material used for the protective layer include SiO, SiO ₂ , MgF ₂ , Sn
Examples thereof include inorganic substances such as O ₂ and Si ₃ N ₄ , and organic substances such as thermoplastic resins, thermosetting resins, and UV curable resins. 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 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, 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. Information is recorded on the optical information recording medium as follows, for example. First, the optical information recording medium is set at a constant linear velocity (1.2 to 1.4 m / in the case of a CD format).
Seconds) or while rotating at a constant angular velocity, recording light such as semiconductor laser light is irradiated from the substrate side or the protective layer side. 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, semiconductor laser light having an oscillation wavelength in the range of 390 to 440 nm is used as recording light. As a preferred light source, a blue-violet semiconductor laser beam having an oscillation wavelength in the range of 390 to 415 nm, a central oscillation wavelength of 850 n
A blue-violet SHG laser beam having a central oscillation wavelength of 425 nm, which is a half wavelength of an m semiconductor laser beam using an optical waveguide device, can be mentioned. In particular, it is preferable to use blue-violet semiconductor laser light in terms of recording density. The information recorded as described above is reproduced by irradiating a semiconductor laser beam from the substrate side or the protective layer side while rotating the optical information recording medium at the same constant linear velocity as above and detecting the reflected light. Can be performed. EXAMPLES 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 Compound (CY-1) was converted to 2,
It was dissolved in 2,3,3-tetrafluoropropanol 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. Length: 0.6m
m) is applied to the surface on the pre-groove side by spin coating, and the recording layer (thickness (in the pre-groove): 80 n
m) was formed. Next, silver was sputtered on the recording layer to form a light reflecting layer having a thickness of 100 nm. Further, a UV curable resin (SD318, manufactured by Dainippon Ink & Chemicals, Inc.) was applied on the light reflection 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 9] According to the present invention, the compound (CY-1) in Example 1 was changed to the compound shown in Table 2 (the amount used was unchanged). An optical disc was manufactured. [Comparative Example 1] to [Comparative Example 6] The compound (CY-1) in Example 1 was changed to the comparative dye compounds (A) to (F) shown below (the amount used was unchanged). A comparative optical disk was manufactured in the same manner except for the above. Embedded image Embedded image [Evaluation 1 as an optical disc] A 14T-EFM signal was recorded on a produced optical disc at a linear velocity of 3.5 m / sec using a blue-violet semiconductor laser beam having an oscillation wavelength of 405 nm, and the recorded signal was reproduced. The laser power at the maximum modulation degree was taken as sensitivity, and the modulation degree and groove reflectance at this time were measured. Recording and recording characteristic evaluation were performed using DDU1000 manufactured by Pulstec. The evaluation results are shown in Table 2. [Table 2] From the results shown in Table 2, the optical discs (Examples 1 to 9) having recording layers containing a compound having specific optical characteristics that are the characteristics of the present invention were compared with Comparative Compounds (A) to (A).
Optical disc having a recording layer containing (F) (Comparative Examples 1 to
Compared to 6), it can be seen that it has high sensitivity to the blue-violet semiconductor laser light, and also provides a high reflectance and a high degree of modulation. The optical information recording medium of the present invention uses a compound having specific optical characteristics as a recording material for the recording layer, so that a short wavelength laser beam having a wavelength of 440 nm or less, particularly versatile. It is possible to record and reproduce information at a high density by irradiating a laser beam of around 405 nm and to have good recording and reproduction characteristics such as high sensitivity, high reflectance, and high modulation degree. In other words, information can be recorded at a higher density than conventional CD-R and DVD-R.
Furthermore, it is possible to record a large amount of information.

Claims (1)

What is claimed is: 1. An optical information recording medium having an amorphous recording layer capable of recording information by irradiating a laser beam having a wavelength of 440 nm or less on a substrate, wherein the recording layer has a laser beam wavelength or less. An optical information recording medium having at least one absorption maximum in a short wavelength region, wherein the wavelength (λ _m ) of the longest absorption maximum is in the range of 340 to 400 nm.