JPH02246033A - Production of information recording medium - Google Patents

Abstract

PURPOSE:To improve adhesion property between a reflecting layer and a protective layer provided on the reflecting layer, durability of the medium, recording/ reproducing characteristics such as C/N and jitter by treating the surface of the reflecting layer with glow discharge. CONSTITUTION:A coating material for a dye recording layer is applied on a disk resin substrate 31 by spin coating to form the dye recording layer 32. Then the metal reflecting layer 35 is formed on the recording layer 32 by sputtering, etc. The reflecting layer thus formed is treated with glow discharge, on which the protective layer 36 is formed. Thus, the recording layer 32 and the reflecting layer 35 are completely covered with the protective layer 36. By treating the reflecting layer 35 with glow discharge, the adhesion between the protective layer 36 and the reflecting layer 35 is enhanced, and moreover, durability of the medium, recording/reproducing characteristics such as C/N and jitter can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention 1] The present invention relates to a method for manufacturing an information recording medium on which information can be written and/or read using a high energy density laser beam.

[Technical Background of the Invention] In recent years, information recording media that use 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 large-capacity still 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.
, In, Te, and other metals or metalloids; or cyanine-based, metal complex-based, quinone-based, and other dyes. Note that an intermediate layer made of a polymeric substance is usually provided on the surface of the substrate on the side where the recording layer is provided, in order to improve the flatness of the substrate, improve the adhesive force with the recording layer, or improve the sensitivity of the optical disc. often.

In addition, for the purpose of improving the durability of the information recording medium, a protective layer is provided on the recording layer, or a recording layer is provided on at least one of the two disk-shaped substrates as a disk structure. An air sandwich structure has been proposed in which these 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 optical discs provided with such an i-retaining layer or optical discs with an air sandwich structure, the recording layer is not in direct contact with the outside air, and information is recorded and reproduced using laser light that passes through the substrate. This has the advantage that the layer will not be physically or chemically damaged, or dust will not adhere to its surface, which will impede information recording and reproduction.

On the other hand, writing and reading information to and from an optical disc is usually performed by the following method.

Information is written 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, causing physical or chemical changes (for example, the formation of pits). information is recorded by changing its optical properties. Information is also read by irradiating the optical disk with a laser beam, and the information is reproduced by detecting reflected or transmitted light depending on changes in the optical characteristics of the recording layer.

As mentioned above, metals and dyes are known as recording materials that form the recording layer of such information recording media. Information recording media using dyes have higher sensitivity than recording materials such as metals. In addition to having advantages in the characteristics of the recording medium itself, such as the above, it also has a great manufacturing advantage in that the recording layer can be easily formed by a coating method. however.

Recording layers made of dyes generally have the disadvantage of low reflectance, so a metal reflective layer is often provided on the dye recording layer in order to improve the reflectance. A protective layer is provided on the reflective layer to protect the layer. The protective layer is advantageous in that it is easier to manufacture and requires less manufacturing cost than other protection methods, such as a method in which the structure of the disk is sandwiched.

However, the protective layer provided on the reflective layer cannot be said to adhere strongly to the first reflective layer, and peeling may occur after the protective layer is formed, or may peel off during long-term storage or use. I often came.

In addition, as described above, the dye recording layer 1 reflective layer and the protective layer 1 are also included. ! An optical disk having a structure consisting of layers records information by changing the reflectance of the recording portion caused by a phase change or a change in the shape of a dye layer, without forming pits. Optical discs with such a configuration cannot be said to have sufficiently excellent recording and reproducing characteristics such as C/N and jitter.
In this respect as well, improvements in the protective layer are desired.

Various studies have been conducted to improve the adhesion of the protective layer.1 For example, attempts have been made to ensure adhesion by increasing the thickness of the protective layer to improve its strength, or by changing the type of the protective layer. Attempts are being made to improve this.

However, if the protective layer is made thicker, the strength will be improved, but the adhesion will be reduced and it will be easier to peel off. Further, when the protective layer is changed, some types of the protective layer have good adhesion, but such a protective layer has a problem in that the strength of the protective layer itself is insufficient. Furthermore, no effective means for improving the recording and reproducing characteristics has been found.

Therefore, it has excellent adhesion to the reflective layer and also has strength as a protective layer. That is, a protective layer that has sufficiently excellent performance in terms of durability and excellent recording and reproducing properties has not been obtained.

[Object of the Invention] The present invention provides an information recording material having a dye recording layer, a reflective layer, and a protective layer provided in this order on a resin substrate, which has a good appearance, improved durability, and excellent recording and reproducing characteristics. The purpose of this invention is to provide a method for manufacturing a recording medium.

[Summary of the Invention] The present invention is a process of providing a recording layer made of a dye that can read and/or write information with a laser by coating on a disc-shaped resin substrate having a hole in the center.

Production of an information recording medium comprising the steps of: forming a reflective layer made of metal on the recording layer; subjecting the reflective layer to glow discharge treatment; and then providing a protective layer on the reflective layer. It's in the method.

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

1) The method for manufacturing the information recording medium, characterized in that the protective layer is provided by coating.

2) The method for manufacturing the information recording medium, wherein the protective layer is coated using a spin coater.

3) The method for manufacturing the information recording medium, wherein the material of the resin substrate is polycarbonate, polyolefin, or cell cast polymethyl methacrylate.

4) The material of the reflective layer is Au, Ag, Cu, Ni, P.
The method for manufacturing an information recording medium as described above, wherein the information recording medium is made of at least one metal selected from the group consisting of t, Cr, 'ri, and Al.

5) The method for manufacturing the information recording medium, wherein the material of the protective layer is an ultraviolet curable resin.

6) The method for producing the information recording medium, wherein the dye is at least one type of dye selected from cyanine dyes, azulenium dyes, phthalocyanine dyes, imidazoquinoxaline dyes, and squarylium dyes.

[Effects of the Invention] In the information recording medium obtained by the above-described specific manufacturing method of the present invention, the surface of the reflective layer is treated by glow discharge, so that the adhesiveness with the protective layer provided on the reflective layer is improved. It has improved markedly. This not only improves the durability of the information recording medium, but also improves recording and reproducing characteristics such as C/N and jitter.

The reason for such improvement in recording and reproducing characteristics is thought to be as follows. That is, since the reflective layer and the protective layer are in extremely strong contact with each other, the entire surface of the reflective layer is pressed down with a uniform force. Therefore, when recording information, changes in the shape of one dye recording layer or the reflective layer and the dye recording layer caused by laser irradiation occur without becoming non-uniform.
It is believed that the signal is recorded accurately.

Furthermore, when a protective layer made of an ultraviolet curable resin having high strength and excellent productivity is provided on the glow discharge treated reflective layer of the present invention, the adhesion of the protective layer to the glow treated reflective layer is Since it is particularly excellent, by adopting such a structure, an information recording medium having significantly improved durability can be obtained.

[Detailed Description of the Invention] The information recording medium obtained by the manufacturing method of the present invention has a basic structure in which a dye recording layer, a reflective layer, and a protective layer are provided in this order on a substrate. In this structure, the dye recording layer is easy to manufacture and has high sensitivity, the reflective layer improves the low reflectance that is a drawback of the dye layer, and the protective layer protects the above two layers and improves the durability of the optical disc. It is based on the idea of sharing the roles of each of the three layers, such as improving sexual performance.

To manufacture an information recording medium having the above structure, first, a recording layer made of a dye is generally coated on almost the entire surface of a substrate using a spin coater or the like. However, normally, a recording layer is not provided on the inner circumferential side of the substrate. In other words, when the optical disk is rotated by a recording/reproducing drive, there is a clamp area on the inner circumferential side of the optical disk for fixing it to a clamp in the drive. Generally, coating is carried out so that the dye does not adhere to the vicinity. The reflective layer provided thereon is generally provided on the dye recording layer or inside the recording layer. Then, on the reflective layer, a protective layer such as a UV curable resin is provided by coating.

In information recording media manufactured in this way, the protective layer formed mainly for the purpose of improving durability does not have very good adhesion with the reflective layer below, and optical discs with the above structure It was found that the recording and reproducing characteristics were not sufficiently excellent.

The inventors of the present invention conducted various studies to solve the above problem, and found that after forming the reflective layer, the reflective layer was subjected to glow discharge treatment, and then a protective layer was provided to improve the adhesion between the reflective layer and the protective layer. It was clear that there was a significant improvement. It has also been found that the information recording medium having the protective layer provided in this manner has excellent recording and reproducing characteristics.

That is, the method for manufacturing an information recording medium of the present invention is carried out, for example, as follows. This will be explained in detail with reference to the attached FIGS. 1 to 3.

FIG. 1 shows a disc-shaped resin substrate 11 with a hole 10 in the center.
, a recording layer 1 made of a dye provided thereon by coating.
2 and a partial cross-sectional view of a bond 13 that is not applied near the periphery of the hole.
A coating liquid for forming a dye recording layer is applied thereon using a spin cord to form a recording layer 12 made of one dye. The area of the uncoated area 13 varies depending on the conditions at the time of coating, but generally, an area where no dye recording layer is provided on the inner peripheral side is secured as a clamp area. If the coating method is a roll coater other than a spin cord, dipping, or the like, this uncoated area 13 usually does not exist.

FIG. 2 shows a disc-shaped resin substrate 21 with a hole 20 in the center.
．． Recording layer 2 made of a dye provided on a substrate by coating
2. A portion consisting of a reflective layer 25 provided thereon, an inner non-recording area 23 provided at the periphery of the chain hole @ 20, and an outer non-recording area 24 provided inside the outer periphery. FIG. On the recording layer 12 made of the dye shown in FIG.
A reflective layer 25 made of metal is formed by sputtering or the like. In this case, the reflective layer 25 may be provided on the dye recording layer 12 shown in FIG. 1, but as shown in FIG. It is preferable to expose the substrate surface by removing a certain dye coating layer 12 and provide the reflective layer and the substrate in contact with each other at the inner and outer peripheries. It is provided up to a part of the exposed part, and the remaining exposed parts of the substrate become the inner non-recording area 23 and the outer non-recording area 24.

The formation of the reflective layer 25 is usually carried out by sputtering or the like while masking these areas in order to secure the inner non-recording area 23 and the outer non-recording area 24.

Alternatively, in Fig. 1, without removing the pigment layers on the inner and outer peripheral sides,
After the reflective layer is provided using the above mask, the dye layers on the inner and outer circumferential sides remaining in the areas where no reflective layer is present are removed by solvent spraying or the like, thereby forming the inner non-recording area 23 and the outer circumferential side. A non-recording area 24 can also be secured. By securing the non-recording areas on the inner and outer circumferential sides, good adhesion can be obtained between the protective layer and the substrate in these areas, contributing to improved durability.

In the manufacturing method of the present invention, it is necessary to subject the thus formed reflective layer to glow discharge treatment.

Glow discharge is a type of gas discharge, and the degree of vacuum is l~100.
0 wTorr, cold cathode discharge current is 0.01-1.
This occurs when the current is around 0mA. It is called a glow discharge because glow emission is observed near the cathode.

In this glow discharge, when the cathode current is small, the discharge does not occur over the entire surface of the cathode, and when the current is increased, the discharge spreads over the entire surface of the cathode while the current density at the discharge generation portion is kept constant. After the discharge spreads over the entire surface of the cathode, increasing the current increases the cathode current density. The period until the discharge spreads over the entire surface of the cathode is called normal glow discharge, and the period after the discharge spreads over the entire surface of the cathode is called abnormal glow discharge.

The glow discharge treatment of the present invention is performed by arranging a substrate provided with a reflective layer at the position of the cathode.

Although the glow discharge may be performed using any device, it is preferable to perform the glow discharge treatment by reverse sputtering using a sputtering device that utilizes the above-mentioned abnormal glow discharge.

Devices include 2-pole RF glow discharge sputter, 2-pole DC
Glow discharge sputters, magnetron sputters, etc. can be used. Using a two-pole RF glow discharge sputter,
It is preferable to perform the glow discharge treatment by reverse sputtering.

The conditions for glow discharge are that the power is 10~2ooow,
It is preferable that the voltage is 500 to 2000 V and the target distance (distance between electrodes) is 30 to 300 mm, and the glow discharge gas is Ar, N2.02, Ne, Kr, Xe, H.
g and mixtures thereof. The glow discharge treatment time is preferably in the range of 0.1 to 5 minutes.A protective layer is provided on the reflective layer that has been treated with glow discharge as described below.0A protective layer is provided after the reflective layer has been treated with glow discharge. It is better that the interval is as short as possible, and is preferably in the range of 0 to 2 hours.

When the above glow discharge treatment is performed on the reflective layer, fine cavities are created on the surface of the reflective layer due to ion implantation, and the surface of the reflective layer becomes porous, or the metal has polar groups due to oxidation, etc. . Therefore, it is considered that the wettability of the surface of the first reflective layer to the protective layer is improved and the adhesion is also strong.

FIG. 3 shows a disc-shaped resin substrate 31 with a hole 30 in the center.
, a recording layer 3 made of a dye provided on a substrate by coating.
2 is a partial cross-sectional view of a reflective layer 35 provided thereon and a protective layer 36 provided on the reflective layer. The protective layer 36 is preferably provided on the reflective layer 35 and on the entire surface of the inner non-recording area 23 and the outer non-recording area 24 in FIG. 2. By forming the protective layer in this way, the dye recording layer 32 and the reflective layer 35 are completely covered by the protective layer 35, so that the protective function of the protective layer can be fully exhibited.In the present invention, the adhesion between the reflective layer and the protective layer is significantly improved. In particular, it is possible to obtain good durability without considering the formation position of the protective layer as described above.

In the information recording medium manufactured in this way, the surface of the reflective layer is treated by glow discharge, so that the adhesion with the protective layer provided on the reflective layer is significantly improved. This not only improves the durability of the information recording medium, but also improves recording and reproducing characteristics such as C/N and jitter.

The reason for such improvement in recording and reproducing characteristics is thought to be as follows. That is, since the reflective layer and the protective layer are in extremely strong contact with each other, the entire surface of the reflective layer is pressed down with a uniform force. Therefore, when recording information, changes in the shape of the dye recording layer or the reflective layer and the dye recording layer caused by laser irradiation occur without becoming non-uniform.
It is believed that the signal is recorded accurately.

Furthermore, when a protective layer made of an ultraviolet curable resin with high strength and excellent productivity is provided on the glow discharge treated reflective layer of the present invention, the adhesion of the protective layer to the glow treated reflective layer is Since it is particularly excellent, by adopting such a structure, an information recording medium having significantly improved durability can be obtained.

The information recording medium of the present invention can be manufactured using, for example, the materials described below.

The disc-shaped resin substrate used in the present invention can be arbitrarily selected from various materials used as substrates for 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 cell-cast polymethyl methacrylate.

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 the 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 polymeric substances such as; organic substances such as silane coupling agents; and inorganic oxides (S i02 , Alz 03
etc.), inorganic substances such as inorganic fluoride (MgF2).

The undercoat layer is formed by, for example, dissolving or dispersing the above substances in a suitable solvent to prepare a coating solution, and then applying this coating solution to the substrate surface using a coating method such as spin code, dip coating, or extrusion coating. can do. The layer thickness of the undercoat layer is generally O, OG5~20.
ILm is in the range, preferably 0. O1~10#Lm
is within the range of

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. As the material, at least one monomer selected from monoesters, diesters, triesters, and tetraesters of acrylic acid (
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 (stambar), then placing the substrate on top of this coating layer. , the substrate and the liquid phase are fixed by curing the liquid layer by irradiating ultraviolet rays through the substrate or the matrix.
Next, by peeling the substrate from the mother mold, a substrate provided with a pregroove layer is obtained. The layer thickness of the pregroove layer is generally in the range from 0.05 to 10 Q pm.

If the substrate material is plastic as in the present invention, the pregroove and/or prepit may be directly provided on the substrate by injection molding or extrusion molding.

A recording layer made of one dye is provided on the substrate (or pregroove layer, etc.). The pigment used for the wood shell is not particularly limited, and any pigment may be used. For example, cyanine pigments, phthalocyanine pigments, biryllium pigments, thiopyrylium pigments, azulenium pigments, squalirium pigments, Ni , metal complex dyes such as Or, naphthoquinone/anthraquinone dyes, indophenol dyes, indoaniline dyes, triphenylmethane dyes, triallylmethane dyes, aluminum/diimmonium dyes, and nitroso compounds. I can do it.

Among these, dyes with a high absorption rate for light in the near-infrared region of 700 to 900 nm are preferred, since semiconductor lasers that emit near-infrared light have been put into practical use as recording and reproducing lasers.

Preferred examples include: i) Cyanine dye: [11(CH3)2N-(OR-CH)s-CH=IN
(CH3)z 0 sentence 04 (R is a hydrogen atom or N(CH3)2) [414p ° −L = 9 (X”−)l/
1 (However, Φ and ! are each an indolenine ring residue, a thiazole ring residue, an oxazole ring residue, a selenazole ring residue, an imidazole ring residue, a pyridine ring residue, which may have an aromatic ring fused thereto, It is a thiazolopyrimidine ring residue or an imidazoquinoxaline ring residue, L is a linking group for forming monocarbocyanine, dicarbocyanine, tricarbocyanine or tetracarbocyanine) (a- is a monovalent anion) ion, m is 1 or 2
and furthermore, X- is Φ, L or! may be substituted on top to form an inner salt, or Φ and L, or L and ψ may be further connected to form a ring) Examples of specific compounds represented by the above general formula Examples include the following a) to k).

2H5,;2ns n- to 4) 1s U4 n-t,;4aw cio skin l 04- C sentence O4 ii) Squalium pigment: 1ii) Azulenium pigment: (However, R1 and R2 , 1li2 and R3, R3 and 714
, R2 R3, R4, when at least one combination of R4 and R5, R5 and R6, and R6 and R7 forms a ring of substituted or unsubstituted heterocycles or aliphatic rings and does not form a chain ring. R5, R6 and R
7 is a hydrogen atom, a halogen atom, or a monovalent organic residue, or R1 and R2, 1li3 and R4, R
At least one of the combinations of 4 and R5, R5 and R6, and R6 and R7 may form a substituted or unsubstituted aromatic ring. A is a divalent organic residue bonded via a double bond. and Z- is an anionic residue. Note that at least one carbon atom constituting the azulene ring may be replaced with a nitrogen atom to form an azaazulene ring. atom, an alkyl group, an acylamide group, an alkoxy group, or a halogen atom, and R1, R2 and R3 are each a hydrogen atom and C1
-C20 substituted or unsubstituted alkyl group, aryl group, heterocycle or cyclohexyl group, A is -NHC
(O- or -CON)I-) ■) Metal complex dye: (However, R1-R4 are each an alkyl group or an aryl group, and 1M is a divalent transition metal source (However, 111
1 and R2 are each an alkyl group or a halogen atom, and M is a divalent transition metal atom) (However, R1 and R2 are each a substituted or unsubstituted alkyl group or aryl group, and R3 is an alkyl group, is a halogen atom or a -N-R5 group (where R4 and R5 are each a substituted or unsubstituted alkyl group or an aryl group), M is a transition metal atom, and n is an integer from 0 to 3. ) (However, (Gatl is a cation necessary to make the complex salt neutral, 1M is Ni, Cu, Go, Pd, or pt, and n is 1 or 2) (However, X is a hydrogen atom , a chlorine atom, a bromine atom, or a methyl group, n is an integer of 1 to 4, and A is a quaternary ammonium group) (However, ICatl is a cation necessary to make the complex salt neutral. Yes, M is Ni
, Cu, Go, Pd or Pt, and n is 1 or 2
) group and/or /X rogen atom, fLl and R2 are each an integer of 1 to 3, R1 and R2
are an amino group, a monoalkylamino group, a dialkylamino group, an acetylamino group, and a benzoylamino group (
containing a substituted benzoylamino group), XI and x2,
nl and R2 and R1 and R2 may be the same or different from each other, M is a Cr or Co atom, and Y is hydrogen, sodium, potassium, ammonium, aliphatic ammonium (including substituted aliphatic ammonium). ) or a ring group ammonium) My) Naphthoquinone-based, anthraquinone-based dye: (However, R is a hydrogen atom, an alkyl group, an allyl group, an amino group, or a substituted amino group) (However, R is a hydrogen atom, is an alkyl group, allyl group, amino group or substituted amine group) υ (wherein R is an integer from hydrogen atom, alkyl group, allyl group, amino group or substituted amine group) to lO) (wherein is a l\rogen atom).

Among these dyes, the method of the present invention can be preferably applied to cyanine dyes, azulenium dyes, squarylium dyes, phthalocyanine dyes, and imidazoquinoxaline dyes. Note that these dyes may be used alone or in a mixture of two or more, and when cyanine dyes are used, the above metal complex dyes or aminium/diimmonium dyes may be used together as a quencher. It's okay.

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 this coating solution to the surface of the substrate to form a coating film, and then drying the coating solution. can.

Examples of the solvent for preparing the dye coating solution include esters such as ethyl acetate, 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, dioxane, alcohols such as ethanol, n-propatool, isopropanol, n-butanol, amides such as dimethylformamide, fluorocarbon solvents such as 2,2.3.3, tetrafluoropropanil, etc. etc. can be mentioned. Note that these non-hydrocarbon organic solvents may contain hydrocarbon solvents such as aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and aromatic hydrocarbon solvents, as long as the amount is within 50% by volume. .

The coating solution also contains antioxidants and UV absorbers.

Various additives such as plasticizers and 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.

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 recording layer may be a single layer or a multilayer, but the layer thickness is generally 0.
．． 01 to 1107t, preferably 0.02
~Igm. Furthermore, the recording layer may be provided not only on one side of the substrate but also on both sides.

A reflective layer of the present invention is provided on the dye recording layer.
By providing a reflective layer, in addition to the effect of improving reflectance,
The effects of improving the S/N ratio when reproducing information and improving the sensitivity when recording information can be obtained.

The light-reflective substance that is the material of the reflective layer is a substance that has a high reflectance to laser light, and examples thereof include Mg, Se,
%Y, Ti, Zr, Hf, V.

Nb, Ta, Cr, Mo, W, Mn, Re.

Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, C
u, Ag, Au, Zn, Cd, An, Ga, In, Si
, Ge, Te, Pb, Po.

Mention may be made of metals and metalloids such as Sn and Bi. Among these, preferred are Au, Ag, Cu,
They are Pt, Al, Cr and Ni. These substances may be used alone, or in combination of two or more or as an alloy.

The reflective layer can be formed on the recording layer by, for example, vapor deposition, sputtering, or ion-blating the above-mentioned light-reflective material.

The layer thickness of the reflective layer is generally in the range of ioo to 3 oooz.

A protective layer is provided on the reflective layer for the purpose of physically and chemically protecting the recording layer and the entire information recording medium. This M retention layer also has the effect of increasing scratch resistance and moisture resistance on the side of the substrate where the recording layer is not provided.

Examples of materials used for the protective layer include 5iO1Si02.5iNa, MgF2.5n02 as inorganic substances.
etc. can be mentioned. In addition, examples of the organic substance include thermoplastic resins, thermosetting resins, UV curable resins, etc., and preferably UV curable resins. In the present invention, when the above substances are provided by coating, Remarkable effects can be obtained. This is particularly effective when the organic substance is applied by coating.

That is, it can also be formed by dissolving a thermoplastic resin, a thermosetting resin, or the like in a suitable solvent to prepare a coating solution, and then applying the coating solution and drying it. U
In the case of V-curable resin, apply the coating solution as it is or dissolve it in an appropriate solvent to prepare a coating solution,
It can also be formed by curing by irradiating UV light. Examples of UV-curable resins include oligomers of (meth)acrylate such as urethane (meth)acrylate, epoxy (meth)acrylate, and polyester (meth)acrylate, monomers such as (meth)acrylic acid ester, and photopolymerization initiators. Common UV curable resins such as UV curable resins can be used. Various additives such as antistatic agents, antioxidants, and UV absorbers may be further added to these coating liquids depending on the purpose. In the present invention, it is preferable to use UV curable resins.

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

In addition to the above, the protective layer can be formed, for example, by laminating a film obtained by extrusion of plastic onto the dye recording layer via an adhesive layer.

Alternatively, it may be provided by methods such as vacuum deposition, sputtering, and coating.

Examples and comparative examples of the present invention are described below. However, each of these does not limit the present invention.

[Example 1] And the following dye: 0.01 mol % added to the above dye Ig was added at 2,2°3.3-
A dye recording layer coating solution (concentration = 2.75% by weight) was prepared by dissolving it in tetrafluoropropanol.

Disc-shaped polycarbonate substrate provided with a tracking guide (outer diameter: 130 mm, inner diameter = 15 mm, thickness:
1.2mm, track pitch = 1.6JLm, group depth 2800mm) on top.

The above coating solution was applied at a rotation speed of 1000 rpm using the spin code method.
After coating at a speed of
The recording layer was dried by rotating at a speed of m for 1 minute to form a recording layer having a thickness of 1200 mm.

A reflective layer having a thickness of 1300 mm was formed on the dye recording layer by sputtering Au.

Glow discharge treatment was performed on the reflective layer by performing reverse sputtering using an RF glow discharge sputtering device under the conditions of pressure crab 2 Pa, electric crab 50 W, voltage: 1 kV, and target distance: 110 mm.

A UV curable resin (trade name: 3070, manufactured by Three Pond Co., Ltd.) is applied as a protective layer onto the above reflective layer using a spin cord method at a rotational speed of 1500 rpm, and then cured by irradiating ultraviolet rays with a high-pressure mercury lamp. A protective layer having a layer thickness of 1 pm was formed.

In this way, an information recording medium consisting of the substrate, the dye recording layer 1 reflective layer and the protective layer was manufactured.

[Comparative Example 1] An information recording medium was manufactured in the same manner as in Example 1 except that the reflective layer was not subjected to glow discharge treatment.

[Evaluation of information recording medium] l) Regarding the information recording medium obtained above, the laser power (recording power ) was recorded at 7 mW, linear velocity: 1.3 m/s, and modulation frequency near 20 kHz, and the C/N was measured using a spectrum analyzer (TR4135: Advantest II) at a resolution band width of 30 kHz.
, Reproduction power: 0.5 mW.

2) The time from rise to fall and the time from fall to rise of the reproduced binary signal were measured many times for each signal length, and the standard deviation thereof was taken as jitter.

3) Regarding the information recording medium obtained above.

After storage for 10 days (80°C, 80% RH), C of above l)
/N was measured.

The results obtained are shown in Table 1.

Table 1 C/N G-2 Tar C/N (dB) (dB)
(as) After 10 days, not only the adhesion between the reflective layer and the protective layer was significantly improved, but also a uniform signal was obtained during recording.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are schematic partial cross-sectional views for explaining the method for manufacturing an information recording medium of the present invention. Example 1 56 20 56 Comparative Example 1
53 23 51 As shown in Table 1,
The information recording medium of Example 1 not only has a better C/N after storage and is more durable than the conventional information recording medium (Comparative Example 1), but also has a high initial C/N. It can be seen that the recording and reproducing characteristics are excellent since the jitter is also low. This is because the information recording medium according to the manufacturing method of the present invention is subjected to a low discharge treatment after carving the reflective layer.
Hole 21.31: Disc-shaped resin substrate 22.32: Dye recording layer 2 parts Area not officially coated: Inner circumference side non-recording area: Outer circumference side non-recording area 35: Reflective layer protective layer l 01 11° 12, 25°36:

Claims (1)

[Claims] 1. A step of providing a recording layer made of a dye on which information can be read and/or written by a laser by coating on a disc-shaped resin substrate having a hole in the center, on the recording layer. A method for producing an information recording medium, comprising: forming a reflective layer made of metal; subjecting the reflective layer to a glow discharge treatment; and then providing a protective layer on the reflective layer.