JP2769912B2 - Information recording medium and method of manufacturing the same - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an information recording medium having a recording layer containing a dye capable of recording (writing) information using a high energy density laser beam, and a metal reflective layer. Things.

[Technical Background of the Invention] In recent years, information recording media using a beam of high energy density such as laser light have been developed and put into practical use. This information recording medium is called an optical disk,
It is used as a disk, an audio disk, a large-capacity still image file, and a disk memory for a large-capacity computer.

The optical disc has a disk-shaped substrate made of glass, synthetic resin, and the like, and Bi, Sn,
A recording layer made of a metal or semimetal such as In or Te; or a dye such as cyanine, metal complex, or quinone.
In general, an intermediate layer made of a polymer substance is provided on the surface of the substrate on which the recording layer is provided, from the viewpoint of improving the flatness of the substrate, improving the adhesive force with the recording layer, or improving the sensitivity of the optical disc. Is often done.

Further, for the purpose of improving the durability of the information recording medium, a protective layer is provided on the recording layer, or as a disk structure, a recording layer is provided on at least one of the two disc-shaped substrates. There has been proposed an air sandwich structure in which the two substrates are joined via a ring-shaped inner spacer and a ring-shaped outer spacer so that the recording layer is located inside and a space is formed. In an optical disc provided with such a protective layer or an optical disc having an air saddle structure, the recording layer does not come into direct contact with the outside air, and information is recorded and reproduced by laser light transmitted through the substrate. This has the advantage that it does not suffer physical or chemical damage, or dust adheres to its surface and does not hinder the recording and reproduction of information.

Writing and reading of information to and from the optical disk are usually performed by the following method.

Writing of information is performed by irradiating the optical disk with a laser beam, and the irradiated portion of the recording layer absorbs the light and locally raises the temperature, causing a physical or chemical change (for example, bit generation). Information is recorded by changing its optical properties. Reading of information is also performed by irradiating the optical disk with a laser beam, and information is reproduced by detecting reflected light or transmitted light corresponding to a change in the optical characteristics of the recording layer.

As the recording material for forming the recording layer of such an information recording medium, metals and dyes are known as described above. An information recording medium using a dye has advantages in characteristics of the recording medium itself, such as higher sensitivity than a recording material such as a metal, and also has a manufacturing advantage that a recording layer can be easily formed by a coating method. Has great advantages. However, the recording layer made of a dye generally has a low reflectance,
Alternatively, there is a disadvantage that it is difficult to obtain a high C / N.

In order to improve the disadvantage that the recording layer made of the dye has a low reflectance, it has been proposed to provide a reflective layer made of a metal on the recording layer. However, a reflective layer made of a metal formed by a conventional method generally has poor adhesion to a recording layer, and thus tends to have poor durability of an information recording medium. Furthermore, if the density of the reflective layer made of this metal is low, the crystal orientation of the reflective layer is poor, or if there are fine holes in the reflective layer, the noise of the information recording medium increases and the recording characteristics (C / N) is reduced and durability is deteriorated. Furthermore, when providing a protective layer by coating on the reflective layer, if fine holes are present in the reflective layer, the protective layer forming coating solution comes into contact with the dye in the recording layer, and the dye is discharged. However, there is a problem that the recording layer is damaged.

[Object of the Invention] The present invention has a dye recording layer and a reflective layer on a substrate,
Provided is an excellent information recording medium having high reflectivity, high C / N value, excellent durability, and a recording layer which is not damaged even when a protective layer is provided by coating, and an easy production method thereof. The purpose is to:

[Summary of the Invention] The present invention is an information recording medium in which a recording layer containing a dye capable of recording information by a laser beam and a reflective layer made of metal are provided in this order on a disk-shaped substrate. The reflection layer has the following formula of 13.9 to 20.0: F = −1 n (I / I _ASTM ) / φ ² (I) [wherein, F = orientation coefficient I = non-oriented surface relative to the oriented surface (where φ is φ> π / 8) X-ray diffraction line intensity ratio I _ASTM = Intensity ratio of X-ray diffraction line of non-oriented surface to oriented surface written on ASTM card φ = oriented surface and non-oriented An information recording medium characterized by having an orientation coefficient defined by an acute angle (rad) with an orientation plane] and a film thickness of 300 to 3000 °.

Further, the present invention is a method for manufacturing an information recording medium in which a recording layer containing a dye capable of recording information by a laser beam and a reflective layer made of metal are provided in this order on a disk-shaped substrate. When the reflection layer is formed by setting the target-substrate distance to 1 (cm), the sputtering gas pressure to P (Pa), and the sputtering rate (film thickness / sputtering time) to R (Å / sec), Performed by sputtering under conditions where l, P and R satisfy the following formula: (l × P) / R ≦ 4 (II)
The following formula of 3.9 to 20.0: F = −1n (I / I _ASTM ) / φ ² (I) [wherein, F = orientation coefficient I = non-oriented surface with respect to the oriented surface (where φ is φ> π / 8 and I _ASTM = Intensity ratio of X-ray diffraction line of the non-oriented plane to the oriented plane, written on the ASTM card φ = between the oriented plane and the non-oriented plane A method for manufacturing an information recording medium, comprising: forming a reflective layer having an orientation coefficient defined by an acute angle (rad)] and a thickness of 300 to 3000 °.

Preferred embodiments of the information recording medium of the present invention and the method of manufacturing the same are as follows.

1) The information recording medium and the method for manufacturing the information recording medium, wherein the reflective layer has substantially no holes having a hole diameter of 50 nm or more.

2) The above dye is a cyanine dye, an azurenium dye, a squarylium dye, a phthalocyanine dye, a naphthalocyanine dye, a pyrylium dye, a thiopyrylium dye, an indophenol dye, an indoaniline dye, or a triphenylmethane dye. The information recording medium and a method for producing the same, comprising one or more dyes selected from the group consisting of quinone dyes, aminium dyes, diimmonium dyes, metal complex dyes, and the like.

3) The information recording medium and the method for producing the information recording medium, wherein the recording layer further contains 0.001 to 0.2 mol parts of a metal complex dye based on 1 mol part of the dye or the dye mixture.

4) The information recording medium and the method of manufacturing the information recording medium, wherein the thickness of the recording layer is in the range of 500 to 2000 °.

5) The information recording medium described above, wherein the material of the plastic substrate is polycarbonate, polyolefin, or cell cast polymethyl methacrylate, and a method of manufacturing the same.

6) The information recording medium described above, wherein the metal comprises at least one metal selected from the group consisting of Au, Ag, Cu, Pt, Cr, Ti, Al, and stainless steel, an alloy thereof, or a mixture thereof. Production method.

7) The information recording medium and the method for manufacturing the information recording medium, wherein the reflective layer is a reflective layer having substantially no holes having a hole diameter of 20 nm or more.

Preferred embodiments of the method for producing an information recording medium of the present invention are as follows.

8) The reflective layer is formed by sputtering under conditions where l and P satisfy the following formula: l × P ≦ 30 (III), and the formed reflective layer is further formed with a hole diameter of 50 nm or more. The method for producing an information recording medium as described above, wherein the layer has substantially no holes.

9) DC sputtering, high frequency sputtering,
The method for manufacturing the information recording medium, wherein the method is performed by magnetron sputtering or ion beam sputtering.

10) The method of manufacturing an information recording medium, wherein the sputtering is performed at a sputtering gas pressure of 10 ^-2 to 10 ² Pa.

[Detailed Description of the Invention] The information recording medium of the present invention has a basic configuration in which a dye recording layer and a metal reflective layer are provided in this order on a disk-shaped substrate.

The disk-shaped substrate in the present invention can be arbitrarily selected from various resin materials used as substrates of conventional information recording media. In view of the optical characteristics, flatness, workability, handleability, stability over time, and manufacturing cost of the substrate, examples of the substrate material include acrylic resins such as cell cast polymethyl methacrylate and injection-molded polymethyl methacrylate; Examples thereof include vinyl chloride resins such as vinyl chloride and vinyl chloride copolymer; epoxy resins; polycarbonate resins, amorphous polyolefins, and polyesters. Preferably, polycarbonate, polyolefin and cell cast polymethyl methacrylate can be mentioned.

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 adhesion, improving solvent resistance of the substrate, 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-methylolacrylamide, styrene / sulfonic acid copolymer, and styrene / vinyl. Toluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate, etc. Molecular substances; organic substances such as silane coupling agents; and inorganic oxides (SiO ₂ , Al ₂ O _3, etc.);
Inorganic substances such as inorganic fluoride (MgF ₂ ) can be exemplified.

The undercoat layer is prepared, for example, by dissolving or dispersing the above substance 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 be formed. The thickness of the undercoat layer is generally 0.005 to 20 μm
And preferably in the range of 0.01 to 10 μm.

Further, a pre-group layer and / or a pre-pit layer may be provided on the substrate (or the undercoat layer) for the purpose of forming irregularities representing information such as tracking grooves or address signals. As a material for the pregroove layer and the like, a mixture of at least one monomer (or oligomer) of acrylic acid monoester, diester, triester and tetraester and a photopolymerization initiator can be used.

The pre-groove layer is formed by first applying a mixed solution composed of the above-mentioned acrylate and a polymerization initiator on a precisely formed master (stamper), and then placing a substrate on the coating solution layer. The liquid layer is cured by irradiating ultraviolet rays through the substrate or the matrix to fix the substrate and the liquid phase. Next, the substrate provided with the pre-groove layer is obtained by peeling the substrate from the matrix. The thickness of the pregroove layer is generally in the range of 0.05 to 100 μm, preferably in the range of 0.1 to 50 μm. When the substrate material is plastic as in the present invention, the substrate may be directly provided with pregrooves and / or prepits by injection molding or extrusion molding.

On the substrate (or pre-groove layer or the like), a recording layer containing a dye capable of recording information by laser light is provided. The dye used in the present invention is not particularly limited, and any dye may be used. For example, cyanine dyes, azulenium dyes, squarylium dyes, phthalocyanine dyes, naphthalocyanine dyes, pyrylium dyes, thiopyrylium dyes, indophenol dyes, indoaniline dyes, triphenylmethane dyes, quinone dyes , Aminium dyes, diimmonium dyes, metal complex dyes, and the like.
Preferably, cyanine dyes, phthalocyanine dyes and naphthalocyanine dyes can be mentioned.

Among these, dyes having a high absorptivity to light in the near-infrared region of 600 to 900 nm are preferred because the use of semiconductor lasers that emit near-infrared light has been put to practical use as recording / reproducing lasers.

These dyes may be used alone or as a mixture of two or more. When a cyanine dye is used, it is preferable to use the metal complex salt dye, an aminium dye, or a diimmonium dye as a quencher. In this case, the quencher preferably contains 0.001 to 0.2 mol parts per 1 mol part of the total dye.

The recording layer can be formed by dissolving the dye and, if desired, a binder in a solvent to prepare a coating solution, then applying the coating solution to the substrate surface to form a coating film, and then drying the coating solution. it can.

Ethyl acetate, as a solvent for the dye coating solution preparation,
Esters such as butyl acetate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; halogenated hydrocarbons such as dichloromethane, 1,2-dichloroethane and chloroform; ethers such as tetrahydrofuran, ethyl ether and dioxane; ethanol; Examples thereof include alcohols such as propanol, isopropanol and n-butanol, amides such as dimethylformamide, and fluorine-based solvents such as 2,2,3,3-tetrafluoropropanol. In addition, these non-hydrocarbon organic solvents, aliphatic hydrocarbon solvent, alicyclic hydrocarbon solvent, as long as it is within 50% by volume,
It may contain a hydrocarbon solvent such as an aromatic hydrocarbon solvent.

Antioxidants, UV absorbers, plasticizers,
Various additives such as a lubricant may be added according to the purpose.

When a binder is used, examples of the binder include cellulose derivatives such as gelatin, nitrocellulose, and cellulose acetate; natural organic polymer substances such as dextran, rosin, and rubber; and carbonized materials such as polyethylene, polypropylene, polystyrene, and polyisobutylene. Hydrogen resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride
Thermal curing of vinyl resins such as polyvinyl acetate copolymers, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl alcohol, chlorinated polyolefins, epoxy resins, butyral resins, rubber derivatives, phenol / formaldehyde resins, etc. And synthetic organic polymer substances such as a precondensate of a hydrophilic resin.

Examples of the application 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. In order to form a favorable alignment state of the dye, it is preferable to use a spin coating method.

When a binder is used as a material for the recording layer, the ratio of the dye to the binder is generally in the range of 0.01 to 99% (weight ratio), preferably in the range of 1.0 to 95% (weight ratio).

For the purpose of improving the recording / reproducing performance, an enhancement layer may be further provided on the recording layer. As a material used for the enhance layer, for example, polybutadiene, a silicon-based resin, a fluorine-based resin, and the like are preferable.

In the information recording medium of the present invention, a reflective layer made of metal is further provided on the dye recording layer. By providing the reflective layer, the effect of improving the reflectance, the S / N at the time of reproducing information, and the effect of improving the sensitivity at the time of recording can also be obtained.

Materials for the reflective layer include Mg, Se, Y, Ti, Zr, Hf,
V, Nb, Ta, Cr, MoW, Mn, Re, Fe, Co, Ni, Ru, Rh, P
d, Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, G
Metals and metalloids such as e, Te, Pb, Po, Sn, Bi and the like can be mentioned. Further, an alloy such as stainless steel may be used. In the present invention, it is preferable to provide a reflective layer made of a metal having a high thermal conductivity at a temperature of 400 ° K and having at least 10 w / m · k or more. Thereby, heat generated when the dye recording layer is irradiated with the laser beam can be rapidly transmitted to the reflection layer. Among these, Au, Ag, Cu, Pt, Al, C
r, Ni and stainless steel are particularly preferred. These substances may be used alone or in combination of two or more kinds or as an alloy.

In the information recording medium of the present invention, the reflective layer is 13.9 to 2
It is characterized by having an orientation coefficient of 0.0. In the present specification, the orientation coefficient is represented by the following formula: F = −1n (I / I _ASTM ) / φ ² (I) [wherein, F = the orientation coefficient I = the non-oriented surface relative to the oriented surface (where φ is φ > Π / 8) X-ray diffraction line intensity ratio I _ASTM = Intensity ratio of X-ray diffraction line of non-orientation surface to alignment surface written on ASTM card φ = Orientation surface and non-orientation Acute angle (rad) with the plane]. The orientation coefficient of the reflective layer is a normal X
Using an X-ray diffractometer, an information recording medium provided with a reflective layer can be easily measured as a sample. An information recording medium in which the orientation coefficient of the reflective layer is smaller than 13.9 has poor durability.

When the reflection layer is made of a multi-component material, the orientation coefficient of the reflection layer is represented by the orientation coefficient of the main component constituting the reflection layer.

For example, in a reflective layer formed of Au, one having an orientation coefficient of 13.9 or more corresponds to one in which the intensity ratio (311) / (111) of the (311) plane to the (111) plane is 1.0 or less.

The reflective layer of the information recording medium of the present invention has a thickness of 300 to 3000, preferably 500 to 2000. If the thickness of the reflective layer is smaller than the above range, the reflectivity of the information recording medium is reduced and pinholes are easily formed, and even if the thickness is larger than the above range, no further improvement in the reflectivity is obtained. Depending on the case, the reflectivity may be reduced, and the cost is merely increased.

The reflective layer of the information recording medium of the present invention has a hole diameter of 50 nm or more,
In particular, it is preferable to have substantially no hole having a hole diameter of 20 nm or more, and more particularly substantially no hole having a hole diameter of 10 nm or more. The holes in the reflective layer can be measured and confirmed with an electron microscope, for example. In the present specification, “having substantially no hole” means that a hole having the hole diameter is within a region of 10 μm × 10 μm.
It means that it exists only at a frequency of 10 or more.

The reflective layer identified as above, according to the present invention,
The target-substrate distance is 1 (cm), the sputtering gas pressure is P (Pa), and the sputtering speed (film thickness / sputtering time)
Is defined as R (Å / sec), a reflective layer having the above film thickness is formed under the condition that l, P and R satisfy the following formula: (l / P) / R ≦ 4 (II) As described above, the metal can be formed by sputtering the above metal. The sputtering speed is
Reflective layer thickness (Å) per unit time (seconds) of sputtering
Expressed by

When sputtering is performed under such a condition that the relationship between l, P and R deviates from the relationship of the above conditional expression, the orientation coefficient of the reflective layer becomes smaller than 17 as shown in Comparative Example 1 below,
As a result, the C / N value of the information recording medium is reduced and the durability is poor. Further, in some cases, a large number of holes having a hole diameter of 60 nm or more are formed in the reflective layer, the C / N value of the information recording medium is reduced, and further, when a protective layer is provided on the reflective layer by coating, The dye in the recording layer may flow out, making it impossible to measure the C / N value of the information recording medium.

It is preferable to perform sputtering under such a condition that l and P satisfy the following formula: l × P ≦ 30 (III).

The sputtering can be performed by any method such as direct current sputtering, high frequency sputtering, magnetron sputtering, and ion beam sputtering. In particular, it is preferable to carry out by DC magnetron sputtering.

In addition, the sputtering is performed at 10 ⁻³ to 10 ³ Pa, particularly, at 10 ⁻² to 1 Pa.
Preferably, the sputtering is performed at a sputtering gas pressure of 0 ² Pa.

As long as the relationship between l, P and R satisfies the above conditions, other conditions are not particularly limited, and conventionally known conditions can be applied to the sputtering. For example,
As the sputtering gas, gases such as Ar, Kr, He, Ne, N ₂ , O ₂ , and Xe can be used, and Ar, He, and N ₂ are particularly preferable.

The sputtering rate can be controlled by controlling the applied power or changing the effective area of the cathode. Generally, the sputtering speed is controlled by controlling the applied power.

When the reflective layer is formed by vacuum deposition of the metal by resistance heating, a large number of holes having a diameter of 60 nm or more are formed in the reflective layer as shown in Comparative Example 2 below.
If the C / N value is lowered and a protective layer is provided on the reflective layer by coating, the dye in the recording layer will flow out, making it impossible to measure the C / N value of the information recording medium.

The information recording medium of the present invention may further include a protective layer on the reflective layer for the purpose of physically and chemically protecting the recording layer and the entire information recording medium. Further, this protective layer may be provided on the side of the substrate where the recording layer is not provided in order to enhance the scratch resistance and the moisture resistance.

Examples of the material used for the protective layer include inorganic substances such as SiO, SiO ₂ , SiN ₄ , MgF ₂ , and SnO ₂ . Further, examples of the organic substance include a thermoplastic resin, a thermosetting resin, a UV-curable resin, and the like, and a UV-curable resin is preferable. In the present invention, a remarkable effect can be obtained when the above substance is provided by coating. This is particularly effective when the organic substance is provided by coating.

That is, it can also be formed by dissolving a thermoplastic resin, a thermosetting resin, or the like in an appropriate solvent to prepare a coating solution, applying the coating solution, and drying.
In the case of a UV curable resin, a coating solution is prepared as it is or dissolved in an appropriate solvent, and then this coating solution is applied.
It can also be formed by curing by irradiating UV light. UV curable resins include oligomers of (meth) acrylates such as urethane (meth) acrylate, epoxy (meth) acrylate, and polyester (meth) acrylate, and monomers such as (meth) acrylic acid ester, and a photopolymerization initiator. And the like can be used. Various additives such as an antistatic agent, an antioxidant and a UV absorber may be added to these coating solutions according to the purpose. In the present invention, it is preferable to use a UV curable resin.

 The thickness of the protective layer is generally in the range from 0.1 to 100 μm.

In addition to the above, the protective layer can be formed, for example, by laminating a film obtained by extrusion of a plastic on the recording layer via an adhesive layer. Alternatively, it may be provided by a method such as vacuum deposition, sputtering, or coating.

Hereinafter, Examples and Comparative Examples of the present invention will be described. However, these examples do not limit the present invention.

Example 1 A dye having the following structural formula: 2 parts by weight of 2,2,3,3-tetrafluoropropanol 100
The recording layer was dissolved in parts by weight to prepare a recording layer coating solution.

On a disc-shaped polycarbonate substrate (outer diameter: 130 mm, inner diameter: 15 mm, thickness: 1.2 mm, track pitch: 1.6 μm, groove depth: 800 mm) provided with a tracking guide,
The coating solution was applied by a spin coating method at a rotation speed of 500 rpm, and dried at a rotation speed of 2000 rpm for 1 minute to form a recording layer having a thickness of 1300 mm.

On the recording layer formed as described above, Au was used as a sputtering gas, and a target-substrate distance: l,
And the sputtering gas pressure: P was changed as described in Table 1,
The sputtering rate was kept constant at 8 (Å / sec), and DC sputtering was performed at 140 W to form a reflective layer having a thickness of 1300Å.

The target at the time of forming the reflective layer as described above
Substrate distance: l, and sputter gas pressure: P, variously changed from A to
Six types of information recording media of F, P and Q were manufactured.

For the above information recording medium, 10μ
Observation in the area of m × 10 μm revealed that there was no hole having a hole diameter of 50 nm or more in the reflective layer.

Further, as a protective layer, a UV-curable resin (trade name: UV3) is formed on the reflective layers of various information recording media manufactured as described above.
070, manufactured by Three Bond Co., Ltd.) by spin coating at a rotation speed of 1500 rpm, followed by curing by irradiating ultraviolet rays with a high-pressure mercury lamp to form a protective layer having a thickness of 1 μm. Manufactured.

Target-substrate distance: set l to 6 cm, sputtering gas pressure:
An information recording medium of I was manufactured in the same manner as above except that the sputtering rate was set to 80 (ス パ ッ タ / sec) by setting P to 20 Pa and the sputtering power to 1.5 W. When the information recording medium was observed in the same manner as described above,
There were no holes larger than 50 nm.

About the obtained information recording medium, C /
N value, orientation coefficient, X-ray diffraction line intensity ratio (311) / (111),
And the durability. Table 1 shows the results.

[C / N Measurement Method] A single signal having a frequency of 720 kHz (duty: 33%) was recorded on the recording layer of the information recording medium at a constant linear velocity of 1.3 m / sec and a recording power of 6 mW.

The recorded signal was reproduced at a power of 0.5 mW and a linear velocity of 1.3.
Under the condition of m / s, spectrum analyzer (RBW: 10kHz, V
(BW: 100 Hz) and the ratio of the output level of the carrier and the noise (C / N) was measured.

[Orientation coefficient] Using an X-ray diffractometer (RADA manufactured by Rigaku Denki Co., Ltd.), place the information recording medium on the sample part as it is, and apply 30 kV, 100 mA, Cu,
θ-2θ scan, 0.02 ゜ step / 0.4 sec, slit: D
For the X-ray diffraction spectrum obtained under the measurement conditions of S1 ゜, SS1 ゜, RS 0.3 mm, I (φ = 0.5148ra
d.) was determined, and the orientation coefficient F was calculated from the formula (I).

[X-ray diffraction line intensity ratio (311) / (111)] Regarding the X-ray diffraction spectrum for which the orientation coefficient was determined (31)
It was calculated from the intensity of the 1) plane and the (111) plane.

[Durability] The information recording medium provided with the protective layer was left in an atmosphere of 80 ° C. and 80% RH for 72 hours, and then the C / N value was measured in the same manner as described above.

[Comparative Example 1] The same as in Example 1 except that the target-substrate distance of sputtering, the sputtering gas pressure: P, and the sputtering speed: R were changed as shown in Table 1 when forming the reflective layer. An information recording medium without a protective layer and an information recording medium with a protective layer were manufactured.

Observation of the information recording medium before providing the protective layer in an area of 10 μm × 10 μm with an electron microscope revealed that the G and H information recording media had a hole diameter of 60 nm in the reflective layer.
There were about 1000 such holes.

With respect to the obtained information recording medium, C /
The N value, orientation coefficient, X-ray diffraction line intensity ratio, and durability were measured. Table 1 shows the results.

Example 2 Instead of the dye used in Example 1, the following structural formula: Sample L and Sample M were manufactured under the same conditions as Sample B and Sample E of Example 1 except that a dye having the following formula was used.

The obtained information recording medium was evaluated in the same manner as in Example 1. Table 2 shows the results.

[Comparative Example 2] Instead of the dye used in Comparative Example 1, Example 2 was used.
Sample N and Sample O were manufactured under the same conditions as Sample G and Sample H of Comparative Example 1, respectively, except that the dyes used in Comparative Example 1 were used.

The obtained information recording medium was evaluated in the same manner as in Example 1. Table 2 shows the results.

As is clear from the results in Tables 1 and 2, when forming the reflective layer by sputtering, the target-substrate distance l, the sputtering gas pressure P, and the sputtering speed R were as described above.
However, by performing sputtering under a condition satisfying (1 × P) / R ≦ 4, a good reflection layer can be formed. Further, it was confirmed that the reflective layer formed under the conditions of the present invention had the same excellent properties even when the dyes of the recording layer were different.

[Effect of the Invention] Since the information recording medium of the present invention has the reflective layer specified as described above, it has high reflectance, high C / N value, excellent durability, and Thus, the present invention is an excellent information recording medium in which the recording layer is not damaged even when the protective layer is provided.

Further, the method for producing an information recording medium of the present invention is a method by which an information recording medium having the above-described excellent properties can be easily produced.

Claims (3)

(57) [Claims] An information recording medium comprising: a recording layer containing a dye capable of recording information by a laser beam; and a reflective layer made of a metal, provided in this order on a disk-shaped substrate. The following formula when the layer is 13.9 to 20.0: F = −1n (I / I _ASTM ) / φ ² (I) [wherein, F = orientation coefficient I = non-oriented surface relative to the oriented surface (where φ is φ> π / 8) Intensity ratio of X-ray diffraction line of I) _ASTM = Intensity ratio of X-ray diffraction line of non-oriented surface to oriented surface written on ASTM card φ = Difference between oriented surface and non-oriented surface An information recording medium having an orientation coefficient defined by an acute angle (rad) between] and a film thickness of 300 to 3000 °. 2. A method for manufacturing an information recording medium, comprising: a recording layer containing a dye capable of recording information by a laser beam, and a reflective layer made of a metal provided on a disc-shaped substrate in this order. The reflection layer is formed by setting the target-substrate distance to l (c
m), the sputtering gas pressure is P (Pa), and the sputtering rate (film thickness / sputtering time) is R (Å / sec),
Performed by sputtering under conditions where l, P and R satisfy the following formula: (l × P) / R ≦ 4 (II)
The following formula of 3.9 to 20.0: F = −1n (I / I _ASTM ) / φ ² (I) [wherein, F = orientation coefficient I = non-oriented surface with respect to the oriented surface (where φ is φ> π / 8 and I _ASTM = Intensity ratio of X-ray diffraction line of the non-oriented plane to the oriented plane, written on the ASTM card φ = between the oriented plane and the non-oriented plane A method of manufacturing an information recording medium, comprising: forming a reflective layer having an orientation coefficient defined by an acute angle (rad)] and a thickness of 300 to 3000 °. 3. The information recording medium according to claim 1, wherein the reflective layer has substantially no holes having a diameter of 50 nm or more.