JPH0449540A - Information recording medium - Google Patents

Abstract

PURPOSE:To obtain the information recording medium having a high reflectivity by laminating an enhancement layer formed of a coating liquid which can dissolve dyes and a reflecting layer on a memory layer contg. dyes on a substrate. CONSTITUTION:The recording layer 12 contg. the dyes which allow recording and reproducing of information by laser beams, a barrier layer 1 which consists of a simple substance or alloy of a metal or semimetal and has 1 to 20nm film thickness, the enhancement layer 14 contg. a high-polymer compd. which can dissolve the dyes of the recording layer 12, and the reflecting layer 15 are superposed on the substrate 11. The barrier layer 13 is the information recording medium consisting of the simple substance or alloy contg. at least one kind of the elements selected from the group consisting of elements, such as Be, B, C, Mg, Al, Si, Sc, Ti, V, Cr, and Mn, and is deposited by DC sputtering. The enhancement layer is formed by curing a UV curing resin or thermosetting resin and this medium is completed by providing a protective layer 16 on the reflecting layer 15.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an information processing apparatus having a recording layer containing a dye that can record (write) and reproduce (read) information using a high-energy-density laser beam. It is related to recording media.

[Technical Background of the Invention] In recent years, information recording media using high energy density beams such as laser light have been developed and put into practical use.

This information recording medium is called an optical disk, and is used as a video disk, an audio disk, a human image file, a large-capacity computer disk memory, and the like.

The basic structure of an optical disk is a disk-shaped substrate made of glass, synthetic resin, etc., and Bi, Sn, etc.
, a metal or metalloid such as In, Te, etc., or a recording layer made of a cyanine-based, metal complex-based, quinone-based dye, etc. Note that an intermediate layer made of a polymeric material is usually provided on the surface of the substrate on which the recording layer is provided, in order to improve the flatness of the substrate, improve the adhesion with the recording layer, or improve the sensitivity of the optical disc. Often provided. Furthermore, a protective layer is provided on the recording layer for the purpose of improving the durability of the information recording medium.

Recording and/or reproduction of information on the optical disc is usually performed by the method described in F.

Information is recorded by irradiating this optical disc with a laser beam, and the irradiated portion of the recording layer absorbs the light, causing a local temperature rise and causing physical or chemical changes (for example, the formation of pits). information is recorded by changing its optical properties. Information is also reproduced by irradiating the optical disk with a laser beam, and by detecting reflected or transmitted light according to changes in the optical characteristics of the recording layer.

As described above, metals, dyes, and the like are known as recording materials forming the recording layer of such information recording media. Information recording media using dyes have advantages in the characteristics of the recording medium itself, such as higher sensitivity compared to recording materials such as metals, as well as manufacturing advantages in that the recording layer can be easily formed by a coating method. It has great advantages.

Conventionally, there has been a problem that recording layers containing dyes have low reflectance, so in information recording media that have recording layers containing dyes, a reflective layer containing metal is provided on the recording layer to reduce the reflectance. Efforts are being made to increase it. Furthermore, an inorganic compound (for example, 5iO1Si02.Si3 N4.Al1N, etc.) is provided between the recording layer containing the dye and the reflective layer containing the metal.
It has also been proposed to increase the reflectance by providing an enhancement layer containing (see European Patent Publication EP 0 353 393 A2).

The enhancement layer 1- is formed by a vacuum film forming technique such as vacuum evaporation or RF sputtering.

When the enhancement layer is formed using the vacuum film formation technique described above, especially when a thick film is required, the film formation time may be long and productivity may be poor, or the film may be exposed to the film formation conditions for a long time. During this time, the temperature of the substrate rises, which causes problems such as deterioration of the layer containing an organic substance, especially the recording layer containing a dye, which is formed on the substrate in advance, and deformation of the substrate.

On the other hand, if the enhancement layer can be formed by coating, the above-mentioned problems can be avoided, and the enhancement layer can be formed very simply and easily without using expensive vacuum equipment. desirable.

However, if the solvent used to prepare the coating solution for forming the enhancement layer is a solvent that can dissolve the dye of the recording layer formed on the prewafer substrate, the coating solution for forming the enhancement layer When coating, the dye is dissolved and the recording layer is destroyed.

Therefore, the solvent used to prepare the coating solution for forming the enhancement layer is limited to a solvent that does not dissolve the dye in the recording layer, and accordingly, the substances constituting the enhancement layer may also dissolve in the recording layer. It is limited to substances that are soluble in solvents that do not dissolve the dye.

In general, most of the above-mentioned dyes dissolve in alcohol-based solvents but not in aliphatic or alicyclic hydrocarbon-based solvents. Therefore, it is necessary to use an aliphatic or alicyclic hydrocarbon solvent. Therefore, in this case, the substance constituting the enhancement layer is limited to organic polymeric materials soluble in aliphatic or alicyclic hydrocarbon solvents.

In the above-mentioned information recording media, the most suitable substance to use as the enhancement layer constituent material depends on the type of dye, the type of reflective layer constituent material, the layer thickness of each layer, the refractive index of each layer, their mutual relationship, and various other factors. It is desirable to be able to choose from as wide a range of substances as possible.

Therefore, there is also a demand for an information recording medium having an enhancement layer formed using an enhancement layer forming coating liquid containing a solvent that dissolves the dye forming the recording layer.

[Object of the Invention] The present invention provides an enhancement layer formed from a coating liquid capable of dissolving the dye, which is provided on a recording layer containing the dye as described above provided on a substrate. It is an object of the present invention to provide an information recording medium having a reflectance of 1, on which a reflective layer is provided.

[Summary of the Invention] The present invention provides a recording layer containing a dye on which information can be recorded and reproduced by laser light on a substrate; 1~20n
A barrier layer having a film thickness of m is provided, and an enhancement layer containing a polymer compound formed from a coating liquid capable of dissolving the dye of the recording layer is provided on the barrier layer. This is an information recording medium that is provided with a reflective layer.

Preferred embodiments of the present invention are as follows.

(1) The barrier layer is Be, B, C, Mg, AI, S
i, sc, Ti, V% Cr, Mn.

Fe%Co, Ni, Cu, Zn, Ga, Ge.

As, Se, Rb, Sr, Y, Zr, Nb.

Mo, Tc, Ru, Rh, Pd%Ag% Cd, In
, Sn, Sb%Te, Cs, Ba, Hf.

Ta, W% Re, Os, Ir, Pt, Au, T1,
The information recording medium described above is made of a single substance or an alloy containing at least one element selected from the group consisting of Pb, Bi, Po, At, Fr, Ra, lanthanide elements, and actinide elements.

(2) The information recording medium as described above, wherein the barrier layer is a layer provided by DC sputtering.

(3) The above information recording medium, wherein the enhancement layer 1- is obtained by curing a UV curable resin or a thermosetting resin.

(4) The information recording medium according to item 2, characterized in that a protective layer is provided on the reflective layer.

[Detailed Description of the Invention] The information recording medium of the present invention has a basic configuration in which a substrate is provided with at least a recording layer containing a dye, a barrier layer, an enhancement layer, and a reflective layer.

The above-mentioned substrate is a substrate made of glass, plastic, or the like. This plastic can be arbitrarily selected from various materials used as substrates of conventional information recording media. In terms of substrate optical properties, flatness, processability, handling, stability over time, manufacturing cost, etc., examples of substrate materials include acrylic resins such as cell cast polymethyl methacrylate and injection molded polymethyl methacrylate; Examples include vinyl chloride resins such as vinyl chloride and vinyl chloride copolymers; epoxy resins: polycarbonate resins, amorphous polyolefins, and polyesters. Preferably, mention may be made of polycarbonate, polyolefin and polymethyl methacrylate. In addition, the shape of the above board is disc-shaped (
It may be an optical disc) or a rectangular shape (optical card).

The surface of the substrate on which the recording layer is provided has improved flatness,
An undercoat layer may be provided for the purpose of improving adhesive strength, improving solvent resistance of the substrate, and preventing deterioration of the recording layer. Examples of materials for the undercoat layer include polymethyl methacrylate,
Acrylic acid/methacrylic acid copolymer, styrene/maleic anhydride copolymer, polyvinyl alcohol, N-methylolacrylamide, styrene/sulfonic acid copolymer,
Styrene/vinyltoluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate/vinyl chloride copolymer, ethylene/vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate organic substances such as polymeric substances such as nitrogen coupling agents; and inorganic oxides (S i 02 , A IL
t Os, etc.), inorganic fluorides (MgFz), and the like.

The undercoat layer can be formed by preparing a coating solution by dissolving or dispersing the above-mentioned substances in a suitable solvent, and then coating the substrate surface with a coating layer 11 using the '44j method such as spin cording, dip coating, or extrusion coating. It can be formed by The thickness of the F coating layer is generally 0.00
It is in the range of 5 to 20 μm, preferably 0.01 to 10
It is in the μm range.

Further, a pre-groove layer and/or a pre-pit layer may be provided on the substrate (or undercoat layer) for the purpose of forming tracking grooves or unevenness representing information such as address signals. The material for the pre-groove layer etc. is at least one type of acrylic acid monoester, diester, triester and tetraester.
or oligomer) and a photopolymerization initiator can be used.

The pre-groove layer is formed by first coating a mixture of the above acrylic ester and polymerization initiator on a precisely made matrix (stamper), then placing the substrate on top of this coating solution layer. Then, the liquid layer is cured by irradiation with ultraviolet rays through the substrate or the matrix, thereby fixing the substrate and the liquid phase.

Next, by peeling off the substrate R1 type, a substrate provided with a pregroove layer is obtained. 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, pregrooves and/or prepits may be provided directly on the substrate by injection molding, extrusion molding, or the like.

A recording layer containing a dye that can record (write) and reproduce (read) information using a laser beam is provided on the substrate (or the pregroove layer, etc.).

The above-mentioned dye is not particularly limited, and any dye may be used. For example, cyanine dyes, phthalocyanine dyes, merocyanine dyes, biryllium dyes, thiopyrylium dyes, azulenium dyes, squarylium dyes, indophenol dyes, indoaniline dyes, triphenylmethane dyes, triallylmethane dyes. Examples include dyes, quinone dyes, aminium dyes, diimmonium dyes, and metal complex dyes.

The dye may be a single dye or a mixture of more than one dye.

Further, especially when using cyanine dyes, merocyanine dyes, etc., it is preferable to use quencher dyes such as 1-metal complex dyes, aminium dyes, diimmonium dyes, etc. together. In that case, it is preferable that the quencher dye is contained in an amount of 0.01 to 0.5 mole part based on 1 mole part of the total dye.

In the present invention, the recording layer is formed by dissolving the dye and, if desired, a binder in a solvent to prepare a coating solution, then applying this coating solution to the substrate surface to form a coating film, and then drying. can be done.

(1) As the solvent for preparing the above-mentioned dye coating solution, ethyl acetate,
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, alcohols such as ethanol, n-propanol, isopropanol and n-butanol, amides such as dimethylformamide, fluorine such as 2,2,3゜3-tetrafluoro-1-propatol, etc. Examples include solvents. In addition, these non-hydrocarbon organic solvents are
Hydrocarbon solvents such as aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and aromatic hydrocarbon solvents may be included as long as the amount is within 50% by volume.

The coating solution also contains antioxidants, UV absorbers, plasticizers,
Various additives such as lubricants may be added depending on the purpose.

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

Examples of the coating method include a spray method, a spin code method, a dip method, a roll coat method, a blade coat method, a doctor roll method, and a screen printing method. In order to form a good alignment state of the dye, it is preferable to use a spin code method. Furthermore, during spin coating, the rotation speed of the spinner is set to 500 to 5000 r, p, m,
It is preferable to carry out the drying time within the range of 5 to 180 seconds.

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

The thickness of the dye recording layer is generally in the range of 200 to 3000 λ, preferably 500 to 2000×.

The barrier layer in the present invention is made of a single metal or metalloid or an alloy and has a thickness of 1 to 20 nm.

The substance forming this barrier layer is a metal or semimetal alone or an alloy, such as Be, B, C1Mg, AI, Si,
5c1Ti, V, Cr, Mn%Fe, co, Ni%C
u, Zn%Ga.

Ge, As% Se% Rh% Sr, Y, Zr.

Nb, Mo, Tc, Ru, Rh, Pd
, Ag.

Cd, In, Sn% Sb, Te, C
s, Ba.

Hf, Ta, W% Re, Os, Ir
, Pt.

Au, TI, Pb, Bi, Po, At
, Fr, Ra, a lanthanoid element, and an actinide element. In particular, substances forming the barrier layer include C, AI, Si, Ti, and C.
r, Ni, Cu, Zn, Zr.

Mo, Rh, Pd, Ag, In, Sn, Sb.

It is preferably a single substance or an alloy containing at least one element selected from the group consisting of Te, Ta, Pt, Au, TI and Bi, more particularly C, AI, Ni%Cu
, Zn, Pt, and Au.

- The barrier layer mentioned above is preferably formed by sputtering (for example, direct current sputtering, radio frequency sputtering, magnetron sputtering, ion beam sputtering), and in particular, the barrier layer formed by direct current (DC) sputtering is preferably formed on the substrate when forming the barrier layer. This is preferable because it does not substantially have an adverse effect on the film or the recording layer. The above sputtering conditions include a target-substrate distance of 11 (am) and a sputtering gas pressure of P.
(Pa), it is preferable that 1 and P satisfy the following formula: % formula % and the speed is 0.1 to 1100 n/sec. Sputtering gas pressure is
It is preferably within the range of 10-2 to 100 Pa.

Moreover, the film thickness of the -F barrier layer is 1 to 20 nm,
It is preferably 1.5 to 15 nm, particularly 2 to 106 m. If the film thickness of the barrier layer is thicker than the above range, the transmittance of the barrier layer becomes small, so that the function and effect of the enhancement layer cannot be sufficiently exerted, and the degree of modulation of the information recording medium decreases, which is not preferable.

Furthermore, if the thickness of the barrier layer is thinner than the above range, the effects of the barrier layer will be reduced. Since the thickness of the barrier layer in the information recording medium of the present invention is small as described above, even if the barrier layer is formed by sputtering, it will have a substantially negative effect on the substrate or the layers previously provided on the substrate. Never.

Plasma treatment (for example, glow discharge treatment, reverse sputtering, etc.) on the surface of the object on which the barrier layer is to be formed and/or the surface of the barrier layer improves the adhesion between the barrier layer and other layers, so it is preferable.

The enhancement layer in the present invention is a layer containing a polymer compound formed from a coating liquid that can dissolve the dye of the recording layer, and can be any layer as long as it can improve the reflectance of the information recording medium. It may be made of any substance. The substance forming the enhancement layer is preferably one obtained by curing a UV curable resin or a thermosetting resin, a thermoplastic resin, or the like.

UV curable resins are prepared by combining polymers and/or oligomers of resin components that are cured by UV light, and a photopolymerization initiator in a solvent such as toluene, diacetone alcohol, ethyl acetate, butyl acetate, butanol, etc. It is dissolved or dispersed in
For example, an enhancement layer can be formed by preparing a coating liquid by dissolving it in an alcohol (such as isopropyl alcohol), applying this coating liquid, and curing it by irradiating it with UV light. Resin components of UV curable resin include urethane (meth)acrylate, epoxy (
(meth)acrylate, (meth)acrylate oligomers such as polyester (meth)acrylate, (meth)acrylate
Examples include acrylic acid esters and the like.

In addition, thermosetting resins, thermoplastic resins, etc. are dissolved in the above-mentioned solvents to prepare a coating solution, and then this coating solution is applied, heated if necessary, and dried to form an enhanced layer. can be formed.

The thickness of the enhancement layer is generally preferably in the range of 30 to 3001 m, particularly preferably in the range of 60 to 200 nm. If the thickness of the enhancement layer deviates from the above range, the enhancement effect will be reduced.

In the information recording medium of the present invention, the reflective layer can be formed of any material as long as it can improve the reflectance of the information recording medium, improve the S/N during information reproduction, and improve the sensitivity during recording. It may be formed from any material.

Materials for the reflective layer include metals and metalloids. Metals and metalloids include Mg, Se, Y, T
i, Zr, Hf, V, Nb.

Ta, Cr, Mo, W, Mn, Re, Fe, co, Ni
, Ru, Rh, Pd, I r%Pt.

Cu, Ag%Au, Zn, Cd, Al, ,Ga.

In, Si, Ge, Te, Pb, Po, Sn.

Bi and the like can be exemplified.

The reflective layer can be formed by vapor deposition, sputtering or ion blasting of a metal or metalloid such as L.

The thickness of the reflective layer is generally in the range of 100 to 3,000 λ, preferably in the range of 500 to 2,000 λ.

In the information recording medium of the present invention, a protective layer may be further provided 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 improve scratch resistance and moisture resistance.

Examples of materials used for the protective layer include inorganic substances such as S i O, S i 02 , S 13 N4,
Examples include Mg F2.5no2. Also,
Organic substances include thermoplastic resins, thermosetting resins, UV
Examples include curable resins, preferably UV curable resins. In particular, the above-mentioned organic substances are preferable because a protective layer can be provided by coating.

When the protective layer is formed using the organic substance listed in L, the protective layer can be formed by a method similar to that described for forming the enhancement layer. Depending on the purpose, various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added to the coating liquid for forming the protective layer. In the present invention, it is preferable to use a U■ curable resin.

The thickness of the protective layer is generally in the range of 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 pressurization of plastic onto -F of the dye recording layer via an adhesive layer. Alternatively, it may be provided by methods such as vacuum deposition, sputtering, and coating.

The structure of the information recording medium of the present invention will be explained with reference to the attached drawings.

FIG. 1 is a cross-sectional view schematically showing the structure of a substrate and each layer of an embodiment of the information recording medium of the present invention.

In FIG. 1, an information recording medium 10 has a recording layer 12 formed on a substrate 11, a barrier layer 13 formed thereon, an enhancement layer 14 formed thereon, and a reflective layer 15 formed thereon. A protective layer 16 is formed thereon.

The substrate 11 is made of plastic that is not affected by alcohol-based solvents. The recording layer 12 is formed by spin-coding a recording layer forming coating liquid prepared by dissolving a dye in an alcohol solvent.

The barrier layer 13 is formed by direct current sputtering of Au. The enhancement layer 14 is formed by spin-coding an enhancement layer forming coating liquid prepared by dissolving a UV curable resin in isopropyl alcohol, and curing it by irradiating it with UV light.

The reflective layer 15 is formed by DC sputtering metal. The protective layer 16 is formed by spin-coding a UV curable resin and curing it by irradiating it with UV light.

When manufacturing the information recording medium 10, if the enhancement layer 14 is formed by direct coating on the recording layer 12 without providing the barrier layer 13, the UV curable resin contained in the coating liquid for forming the enhancement layer is The dye in the recording layer is dissolved in various solvents such as silica or the solvent used to dilute the UV curable resin (for example, isopropyl alcohol), and the recording layer is destroyed, making it impossible to obtain an information recording medium. Not possible (see Comparative Example 1). However, when the barrier layer 13 is provided, the recording layer 1
2 is not affected by the above-mentioned solvent in the coating solution for forming the enhancement layer, so the recording layer 12 and the enhancement layer 14 can sufficiently perform their respective functions, making it an excellent information recording medium. (See Example 1).

As is clear from the above, the information recording medium of the present invention can be easily manufactured with high productivity by optimally selecting the substance forming the enhancement layer regardless of the dye recording layer. As mentioned above, the barrier layer is generally formed by sputtering, but since the barrier layer is thin and can be formed in a short time, it does not have an adverse effect on the substrate or other layers.

In the information recording medium of the present invention, if there is a possibility that the substrate or the undercoat layer may be adversely affected by the recording layer coating liquid, a barrier layer as described above may be provided on the surface of the substrate or the undercoat layer. .

Next, examples of the present invention will be shown.

[Example 1] An information recording medium having the cross-sectional structure shown in FIG. 1 was manufactured in the following manner.

The substrate 11 is a disc-shaped polycarbonate substrate provided with groups (outer diameter: 120 mm, inner diameter: 15 mm).
, thickness: 1.2 mm, group width: 2 0.6 μm, depth of 1 group: 10100 nm.

A recording layer coating solution prepared by dissolving 1.8 parts by weight of the dye having the structural formula: n-C4H9n-cJg l04- in 100 parts by weight of 2,2,3.3-tetrafluoropropanol was applied to the substrate. 11, the number of rotations is 10 using the spin code method.
After coating for 30 seconds at a speed of 00 r, p, m, it was dried for 1 minute to form a recording layer 12 with a layer thickness of 1100 nm.

For the recording layer 12, Au was DC sputtered using Ar as a sputtering gas, a target-substrate distance of 11:95 mm, a sputtering gas pressure of 2 Pa, 2 nm/sec, and 480 W to a film thickness of 5 nm. barrier layer 13
was formed.

1 of the barrier layer 13 is a UV curable resin (product name: UV3
A coating solution for forming a barrier layer prepared by dissolving 5 parts by weight of 070 (manufactured by ThreeBond) in 95 parts by weight of isopropyl alcohol was heated at a rotation speed of 1500 r by a spin cord method.
After coating at speeds of p and m, the enhancement layer 14 with a layer thickness of 1100 nm is cured by irradiating ultraviolet rays with a high-pressure mercury lamp.
was formed.

On the enhancement layer 14, a reflective layer 15 having a thickness of 1100 nm was formed by sputtering Au under the same conditions as for forming the barrier layer.

On the reflective layer 15, a UV curable resin (product name: UV30
70 (manufactured by Three Bond) by spin coating at a rotation speed of 2000 r, p, m, and was then cured by irradiation with ultraviolet rays using a high-pressure mercury lamp to form a protective layer 16 with a layer thickness of 2 μm.

Regarding the obtained information recording medium, mirror reflectance, C/N value, and 3T modulation degree were measured by the following methods. The results are shown in Table 1.

[Mirror Reflectance] When an unrecorded area without a group was reproduced, the energy of the incident laser beam and the energy of the reflected light were measured, and the ratio was determined as a percentage.

[C/N measurement method] A semiconductor laser beam with a wavelength of 780 nm is used in the recording layer of the information recording medium, a constant linear velocity of 1.3 m/s, and a recording power of 6 m.
W, modulation frequency 720kHz (duty: 33%)
A single signal was recorded.

'', the recorded signals were analyzed using a spectrum analyzer (
RBW: 10kHz, VBW: Zo.

The ratio of carrier to noise output level (C/Hz)
N'') was measured.

[3T modulation degree] 1- When information recorded under the conditions described above is reproduced, the maximum value of the reflected light level of the DC reproduction waveform is A, the minimum value is B,
The reflected light level in a region without a pregroove was determined as R, and the modulation degree = (A-B)/RX100%.

[Comparative Example 1] The same procedure as in Example 1 was carried out except that the barrier layer 13 was not formed, and each layer other than the substrate and the barrier layer was made of the same material and had the same configuration as the information recording medium obtained in Example 1. An information recording medium was manufactured.

The mirror reflectance, C/N value, and 3T modulation degree of the obtained information recording medium were measured by the methods described above. The results are shown in Table 1.

[Comparative Example 2] Example 1 except that the thickness of the barrier layer 13 was changed to 0.5 nm.
An information recording medium made of the same material and having the same structure as the information recording medium obtained in Example 1 was manufactured in the same manner as in Example 1.

The mirror reflectance, C/N value, and 3T modulation degree of the obtained information recording medium were measured by the methods described above. The results are shown in Table 1.

[Comparative Example 3] An information recording medium having the same material and the same configuration as the information recording medium obtained in Example 1 was manufactured in the same manner as in Example 1 except that the thickness of the barrier layer 13 was changed to 50 nm. did.

The mirror reflectance, C/N value, and 3T modulation degree of the obtained information recording medium were measured by the methods described above. The results are shown in Table 1.

[Comparative Example 4] In the same manner as in Example 1 except that the barrier layer 13 and the enhancement layer 14 were not formed, each layer other than the substrate and the barrier layer was made of the same material as the information recording medium obtained in Example 1. An information recording medium having the same configuration was manufactured.

The mirror reflectance, C/N value, and 3T modulation degree of the obtained information recording medium were measured by the methods described above. The results are shown in Table 1.

Table 1 As is clear from the results in Table 1, the information recording medium obtained in Example 1 had excellent mirror reflectance, C/N, and 3T modulation. The information recording medium obtained in Comparative Example 1 and Comparative Example 2 was unsuitable because the dye recording layer was eroded, and the information recording medium obtained in Comparative Example 3 had high mirror reflectance and C/N. However, the 3T modulation degree is low, and the information recording medium obtained in Comparative Example 4 has a low reflectance because there is no enhancement effect.

[Effects of the Invention] The information recording medium of the present invention has the above-specified barrier layer provided between the recording layer containing a dye and the enhancement layer formed from a coating liquid capable of dissolving the dye. Because of this, the recording layer is not adversely affected during the formation of the enhancement layer, and it exhibits remarkable effects such as excellent reflectance, C/N, modulation degree, and the like.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing the structure of a substrate and each layer of an embodiment of the information recording medium of the present invention. 10: Information recording medium, 11: Substrate, 12: Recording layer, 13: Barrier layer, 14: Enhancement layer, 15: Reflective layer, 16: Protective layer.

Claims (1)

[Claims] 1. A recording layer containing a dye that can record and reproduce information by laser light is provided on the substrate, and a film of 1 to 20 nm thick made of a metal or semimetal or an alloy is formed on the recording layer. A barrier layer is provided on the barrier layer, an enhancement layer containing a polymer compound formed from a coating liquid capable of dissolving the dye of the recording layer is provided, and a reflective layer is provided on the enhancement layer. An information recording medium made up of