JPH03203047A - Information recording medium - Google Patents

Abstract

PURPOSE:To improve the surface protective function as well as to obtain antireflection effect by forming an antireflection layer having specified refractive index and thickness by curing a mixture liquid of florine-contg. resin and monomers or oligomers containing polymerizable double bonds. CONSTITUTION:An antireflection layer 13 having specified refractive index and thickness satisfying formulae I and II is formed on the surface of a sub strate 11 opposite to the side for recording layer 12 on the outgoing side of laser beam. The layer 3 consists of a mixture of monomers and/or oligomers containing polymerizable double bonds, and fluorine-contg. resin or fluorine- contg. monomers. In the formulae I, II, ns is the refractive index of the sub strate, (n) is the refractive index of the antireflection layer, lambda is the wavelength of laser beam used for reproduction and (d) is the thickness of the antireflection layer. Thereby, the layer has high hardness, low refractive index and higher surface protective function as well as antireflection effect. Since the used resin is liquid or soluble in an org. solvent, the antireflection layer 13 can be easily formed by coating at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an information recording medium on which information can be recorded or reproduced using a laser.

[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 generally called an optical disk and is used as a video disk, an audio disk, a large-capacity still image file, and a large-capacity computer disk memory. moreover,
Optical carts, optical tapes, and the like are also known as information recording media.

Video discs, audio discs (compact discs (CDs)), etc. are already in practical use as playback-only optical discs, and information can be written on them.R
A W (Direct Read AfterWri)
te) type optical discs, or erasable type optical discs on which information can be rewritten, are also being developed.
Some of them have been put into practical use.

The basic structure of such a RAW type information recording medium is a disc-shaped transparent substrate made of plastic, glass, etc., and a recording layer made of a metal or semimetal such as Bi or SnsInsTe, or a dye provided thereon. has. Information is written on an optical disk by, for example, irradiating the optical disk with a laser beam.

Laser irradiation is generally performed by focusing the laser on the recording layer or signal forming surface through a substrate made of a translucent material, in order to reduce the occurrence of misreading due to dust during recording or reproduction. It is done. This is done in the same way for both recording optical discs and reproducing optical discs. However, by irradiating the laser from the substrate side in this manner, while recording or reproducing is less likely to be affected by dust or the like, there is a problem in that the amount of light is lost due to reflection of the laser on the substrate surface.

For this reason, in a recordable information recording medium, a large laser power is required during recording, and since the amount of reflected signals is small during reproduction, there is a problem that tracking errors and reading errors occur. Alternatively, if there is little difference in refractive index between the substrate and the recording layer, there is a problem that focusing is likely to be performed on the substrate rather than the recording layer.

In order to solve this problem, providing an antireflection layer on the surface of the substrate is disclosed in JP-A-60-89844 and JP-A-60-138749. JP-A No. 60-89844 discloses that an optical disk for reproduction is used as an anti-reflection layer, the hC refractive index is different from that of the substrate, and the layer thickness d is d-λ/4n (however, for humans, (Table shows the wavelength of the laser used during reproduction) (However, λ represents the refractive index of the antireflection layer.
Layers made of materials such as: Also, JP-A-6
0-138749 discloses an optical disc for recording or reproduction, in which the antireflection layer has a refractive index of n
= FT, (where ns represents the refractive index of the substrate) (where λ represents the refractive index of the antireflection layer), and the layer Nd is
A layer made of a material such as MgF2, 3N a F-A IF 3 having a value in a range satisfying the same d=λ/4 n as described above is disclosed.

The anti-reflection layer described above is effective in preventing the above-mentioned tracking errors and reading errors because it reduces the reflectance on the substrate surface, but since the material of the anti-reflection layer is inorganic, it is difficult to To form the film, it is necessary to perform vacuum film formation such as vacuum evaporation or sputtering, which has disadvantages in manufacturing such as high cost and complicated process. Furthermore, the surface of such an inorganic layer does not have sufficient hardness, etc.
There is a problem with being easily damaged.

[Objective of the Invention J An object of the present invention is to provide a novel information recording medium having an antireflection layer that can be easily manufactured by a coating method.

Another object of the present invention is to provide a new information recording medium, which is an optical disc having an antireflection layer, which can be recorded with low recording power, and has an increased gain of reproduction signals such as servo signals or information signals. purpose.

Another object of the present invention is to provide a novel information recording medium that has a high reflectance and does not cause reproduction errors such as tracking errors when reproducing recorded signals.

A further object of the present invention is to provide an information recording medium having a high-strength antireflection layer that is excellent not only in preventing a decrease in reflectance but also in protecting an optical disk, such as preventing scratches on the surface.

[Summary of the Invention] The present invention comprises a substrate provided with a recording layer on which information can be written or read by a laser, and an antireflection layer provided on the surface of the substrate on the side where the recording layer is not provided. In the information recording medium, the antireflection layer is made of a cured product of a mixture of a monomer and/or oligomer having a polymerizable double bond and a fluorine-containing resin, and has the following formula (I): rFV, xO, 8≦ n≦FGx 1.2 (
I ) (where n5 represents the refractive index of the substrate) (however, λ represents the refractive index of the antireflection layer) and the following formula (■): λ/4nX0.9≦ d≦λ/4nx 1. + (I
I) (However, λ represents the wavelength of the laser used during reproduction)
(However, λ represents the refractive index of the antireflection layer, and d represents the layer thickness of the antireflection layer.) In an information recording medium in which a recording layer on which information can be written or read by a laser is provided on the substrate, and an antireflection layer is provided on the surface of the substrate on which the recording layer is not provided, the antireflection layer is , consisting of a cured product of a mixture of a fluorine-containing monomer having a polymerizable double bond and other monomers and/or oligomers, and having a refractive index within a range satisfying the following formula (I) and the above formula: (■): The information recording medium (B) is characterized in that the layer thickness is within a range that satisfies the following.

Preferred embodiments of the information recording medium (A) or (B) of the present invention are as follows.

1) The information recording medium (A) or (B), wherein the polymerizable double bond is an acryloyl group or a methacryloyl group.

2) The information recording medium (A) above, wherein the fluorine-containing resin described in (g) is a polymer, coelectric polymer, or block polymer that is soluble in an organic solvent and contains a fluorine-containing monomer as a polymerized unit.

3) The information recording medium (A), wherein the fluorine-containing resin is a comb-shaped graft polymer composed of a fluorine-containing acrylic monomer and a methacrylic acid ester, a fluoroolefin/vinyl ether copolymer, or a fluorine-containing epoxy resin. ).

4) The information recording medium (B), wherein the fluorine-containing monomer is an acrylic ester or a methacrylic ester and has a fluorinated carbon in the ester side chain.

5) The above information recording medium (A), wherein the ratio of the above monomer and/or oligomer to the fluorine-containing resin is in the range of 98:2 to 30:0 by weight.

6) The information recording medium (B), wherein the ratio of the fluorine-containing monomer to the monomer and/or oligomer other than the fluorine-containing monomer is in the range of 98=2 to 30:70 by weight.

7) The above-mentioned information recording medium (A) or (B), characterized in that the above-mentioned thickness is in the range of 500 to 1000 nm.

8) The above-mentioned information recording medium (A) or (B), wherein the above-mentioned recording layer is a layer consisting of one dye.

9) The above-mentioned information recording medium (A) or (B), characterized in that a reflective layer is laminated on the above-mentioned recording layer.

10) The above information recording medium (A) characterized in that a reflective layer and a protective layer are laminated in this order on the L recording layer.
) or (B).

Incidentally, the refractive index of each layer of the present invention was measured as follows.

The substrate was measured as it was at 23° C. using light with a wavelength of 780 nm (semiconductor laser).

Anti-reflection layer, 500% coated on a glass plate using a spin coater method.
A thin film of ~1500X was formed, and this was heated to a wavelength of 780 nm (
Measurements were made at 23°C using light from a semiconductor laser).

Generally, the refractive index of the plastic substrate material is 1.4 to 1.
．． It is 6.

[Effects of the Invention] As described above, the present invention provides an ultraviolet curable type of monomer and oligomer having a polymerizable double bond on the substrate surface on the laser beam incident side, which is the surface opposite to the substrate surface having the recording layer. An antireflection layer made of a cured mixture of a resin and a fluorine-containing resin or a fluorine-containing monomer is provided.

Since such an antireflection layer made of a cured product of a fluorine-containing ultraviolet curable resin uses a liquid or organic solvent-soluble resin, it can be manufactured easily and at low cost by a coating method. In addition, by incorporating a fluorine-containing monomer with a low refractive index or a fluorine-containing compound of a fluorine-containing resin into an ultraviolet curable resin that generally has high hardness and high strength, it has a relatively low refractive index, that is, a large An antireflection layer having an antireflection effect and high film strength can be obtained.

As described above, the antireflection layer of the present invention has the function of preventing reflection of light on the substrate surface and preventing a decrease in reflectance on the surface of the recording layer, similar to the conventional optical disc having an antireflection layer. Therefore, information can be recorded with low laser power, and the gain of a reproduction signal such as a servo signal for tracking or an information signal can be increased. Thereby, when reproducing a recorded signal, occurrence of reproduction errors such as tracking errors can be significantly reduced.

Furthermore, since the antireflection layer of the present invention uses an ultraviolet curable resin as described above, it has high hardness and strength, so it has protective functions such as preventing scratches on the surface and improving the durability of optical discs. It also shows.

[Detailed Description of the Invention] The present inventors have devised information with an anti-reflection layer that can be recorded with a small laser power and has a large amount of reflected signal when the obtained recorded signal is reproduced, that is, there are fewer tracking errors and reading errors. Research has been conducted to develop a recording medium that is easy to manufacture and has excellent durability.

As mentioned above, it is already known to provide an antireflection layer on the surface of the substrate on the side where there is no recording layer in order to increase the amount of reflected signals during reproduction. Then, the layer thickness d is d=
λ/4n (however, e represents the wavelength of the laser used during reproduction) (however, λ represents the refractive index of the antireflection layer), and the refractive index is n=-/""'ii'-, (however, It is also known that ns represents the refractive index of the substrate (where λ represents the refractive index of the antireflection layer). However, since such an antireflection layer uses an inorganic material such as MgF2, it is necessary to perform vacuum film formation by sputtering or the like to provide this layer. Therefore, there are problems such as high cost and long manufacturing time, and the formed film has insufficient strength and surface hardness, and the surface is easily scratched and has poor durability. The present inventors have conducted various studies in search of a material that can be formed by coating on the surface of a substrate, has an excellent antireflection layer function, and also has an excellent protective function.

The inventors have found that among the above materials, ultraviolet curable resins generally have high hardness and strength, but their refractive index is much lower than that of plastic, which is the material for the substrate of optical disks. However, it is difficult to say that a remarkable antireflection effect can be obtained. In addition, fluorine-containing compounds such as fluorine-containing monomers and fluorine-containing resins have a relatively low refractive index and can provide a remarkable antireflection effect, but the strength of the resulting coating may not be high. It became clear.

Based on this knowledge, we conducted further studies and found that the material for forming the antireflection layer is a UV-curable resin made of mono-7- and/or oligomers having polymerizable double bonds that contains fluorine. It has been found that the above object can be achieved by using a mixture to which a resin or a fluorine-containing monomer is added and photocuring this to form an antireflection layer.

That is, as an antireflection layer, a cured product of a mixture of a monomer and/or oligomer having a polymerizable double bond and a fluorine-containing resin, or a fluorine-containing monomer having a polymerizable double bond and a polymerizable resin other than the fluorine-containing monomer is used. Consisting of a cured product of a mixture with a monomer and/or oligomer having a double bond, and having the following formula (Fl)X O, 8≦n≦fj; -x 1.2
(I) (However, ns represents the refractive index of the substrate) (However, λ
represents the refractive index of the antireflection layer) and the following formula (■): λ/4nX0.9≦d≦λ/4nx 1.1 (I
I) (However, E indicates the wavelength of the laser used during reproduction.)
(However, λ represents the refractive index of the antireflection layer, and d represents the layer thickness of the antireflection layer.) A layer having a thickness within a range that satisfies the following is formed on the surface of the substrate opposite to the recording layer. This can be achieved using an information recording medium. By adopting such a configuration, the refractive index can be lowered while maintaining the high strength of the ultraviolet curable resin.

The information recording medium of the present invention will be explained in detail with reference to the accompanying drawings.

FIG. 1 and FIG. 2 are examples of cross-sectional views showing the basic structure of the information recording medium of the present invention.

FIG. 1 shows a substrate 11 and a recording layer provided thereon! 2 and an antireflection layer 13 provided on the surface of the substrate opposite to the recording layer. FIG.

FIG. 2 shows the substrate 21. On top of that, a recording layer 22, a reflective R24
FIG. 3 is a cross-sectional view of an information recording medium in which a protective layer 25 and a protective layer 25 are sequentially laminated, and an antireflection layer 23 is further provided on the surface of the substrate on which the recording layer is not provided.

The substrate of the information recording medium (optical disk) shown in Fig. 1 or Fig. 2 above is generally made of a plastic material such as polycarbonate, and the recording layer is made of a material such as metal, dye, or polymer that can be recorded by laser. good. When a reflective layer and a protective layer are provided on the recording layer as shown in FIG. 2, the recording layer is generally made of a dye having a low reflectance.

The antireflection layers 13 and 23 formed on the surface of the substrate on the side where the recording layer is not provided have a refractive index n of FC
(ns is the refractive index of the substrate) is preferable because the reflectance on the substrate surface can be made close to 0, and the layer thickness d
By setting λ to a value close to λ/4n (λ is the wavelength of the laser used during reproduction, n is the refractive index of the anti-reflection layer), the phases of the light reflected on the substrate and the light reflected on the anti-reflection layer are approximately equal to each other. This is preferable since the phase is reversed and the reflectance on the substrate surface can be reduced. For example, when the substrate is made of polycarbonate, the refractive index of polycarbonate is 1.58, so the refractive index of the antireflection layer is around 1.26 (1.01 to 1 from formula (I)).
．． When the refractive index (n) of the antireflection layer is 1.45 and the wavelength (n) of the laser during reproduction is 7 aonm, the layer thickness is preferably within the range of 13 nm.
It can be said that it is preferable that it is around 50X (according to formula (n), it needs to be in the range of 1210 to 1479X).

In the present invention, the antireflection layer may be made of a photocured mixture of a fluorine-containing resin or a fluorine-containing monomer added to an ultraviolet curable resin made of a monomer and/or oligomer having a polymerizable double bond. is necessary. The antireflection layer of the present invention can be provided by using these resins and forming the antireflection layer with the refractive index and layer thickness set within the above ranges. In the present invention, these resins can be easily formed by coating and drying the resin on the surface of the substrate.

In addition, an example in which a copolymer formed by UV curing of an acrylic monomer and a fluorinated acrylic monomer similar to the structure of the present invention is formed as a protective layer on the surface of the substrate on which the recording layer is not provided is disclosed in Japanese Patent Application Laid-Open No. It is described in No. 62-21113.

However, since this layer is a protective layer, the layer thickness is as thick as 20 μm, and the antireflection effect of the present invention is hardly obtained.

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

The substrate used in the present invention can be arbitrarily selected from various materials used as substrates for conventional information recording media. Examples of substrate materials include glass (n
= 1.52-1.55), polymethyl methacrylate
Acrylic resin (n = 1.49) such as h (n = 1.49)
1.45-1.50); Polyvinyl chloride (n = 1
．． 54-1.55), vinyl chloride resins such as vinyl chloride copolymers; epoxy resins (n=1.55); polycarbonate resins (n=1.58), amorphous polyolefins (n=1°51-1.55); 55) and polyesters (n = 1.52-1.57). Preferred materials include polycarbonate, polyolefin, and cell-cast polymethyl methacrylate from the viewpoint of substrate optical properties, flatness, processability, handleability, stability over time, manufacturing cost, and the like.

The antireflection layer of the present invention needs to be formed on the surface of the substrate on which the recording layer is not provided. In the present invention, a fluorine-containing resin dissolved in an organic solvent or an ultraviolet curable resin containing a fluorine-containing monomer is prepared as it is or further dissolved in an organic solvent to prepare a coating solution, and the coating solution is coated on a substrate and dried (photocuring).
By doing so, an antireflection layer is provided. The antireflection layer is formed by forming a recording layer on the substrate, optionally a reflective layer,
After forming the protective layer etc., it may be provided on the side of the substrate where the recording layer is not provided, or it may be provided first on the side of the substrate where the recording layer is not provided before forming the recording layer.

The antireflection layer made of a cured product of an ultraviolet curable resin containing a fluorine-containing resin or a monomer of the present invention is formed by curing a monomer and/or oligomer having a polymerizable double bond by irradiation with ultraviolet rays or electron beams. It is something that

In the present invention, the group having a polymerizable double bond is preferably an acryloyl group or a methacryloyl group.

Examples of the monomers and oligomers having polymerizable double bonds used in the present invention include the following (meth)acrylates (a) to (j).

(a) Poly(meth)acrylates of N aliphatic, alicyclic and aromatic di- to hexavalent polyhydric alcohols and polyalkylene glycols: e.g. ethylene glycol, propylene glycol, 1
, 3- or 1,4-butanediol, hexanediol, neopentyl glycol, cyclohexanediol, trimethylolethane, trimethylolpropane, glycerin, sorbitol, pentaerythritol, dipentaerythritol, hydrogenated bisphenol A, and other polyhydric alcohols; Examples include poly(meth)acrylates of polyhydric alcohols such as diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, and the like.

(b) Poly(meth)acrylates of polyhydric alcohols in the form of aliphatic, alicyclic, and aromatic polyhydric alcohols with 2 to 6 slightly added alkylene oxides; for example, bisphenol A dioxyethyl ether, etc. Examples include poly(meth)acrylates of polyhydric alcohols obtained by adding ethylene oxide or propylene oxide to polyhydric alcohols such as trimethylolpropane, pentaerythritol, glycerin, and bisphenol A.

(C) Poly(meth)acryloyloxyalkyl phosphate ester; Obtained by reaction of hydroxyl group-containing (meth)acrylate with phosphorus pentoxide, such as poly(meth)acryloyloxyethyl phosphate, poly(meth)acryloyloxy Examples include propyl phosphate.

(d) Polyester poly(meth)acrylate: Polyester poly(meth)acrylate is usually (meth)
It is synthesized by esterifying acrylic acid, polyhydric alcohol, and polyhydric carboxylic acid. It is assumed that the main component is poly(meth)acrylate, which is a polyester type polyhydric alcohol.

For example, di(meth)acrylate of polyester diol of succinic acid and ethylene glycol, di(meth)acrylate of polyester diol of maleic acid and ethylene glycol
Acrylate, di(meth)acrylate of polyester diol with phthalic acid and diethylene glycol, poly(meth)acrylate of polyester diol with adipic acid and triethylene glycol, poly(meth)acrylate of polyester polyol with tetrahydrophthalic acid and trimethylolpropane Examples include acrylate, poly(meth)acrylate of polyester polyol of tetrahydrophthalic acid and pentaerythritol, and the like. Among these polyester poly(meth)acrylates, when using aliphatic or alicyclic polycarboxylic acid-based polyester poly(meth)acrylates rather than aromatic polycarboxylic acid-based ones such as phthalic acid, This has the advantage that the crosslinked cured product has better physical properties such as weather resistance and toughness.

(e) Epoxy poly(meth)acrylate; 2 in the molecule
(meth)acrylic acid, (meth)acrylate having a carboxyl group, or (meth)acrylic acid or (meth)acrylate having a carboxyl group and a polybase in an epoxy resin having more than one epoxy group. It is synthesized by reacting a mixture with an acid. Alternatively, there is also a method of reacting an epoxy group-containing (meth)acrylate with a polyhydric carboxylic acid.

For example, the addition reaction between various epoxy resins such as bisphenol A diglycidyl ether type, glycerin diglycidyl ether type, polyalkylene gellicol diglycidyl ether type, polybasic acid diglycidyl ester type, and cyclohexene oxide type, and (meth)acrylic acid. Things can be given.

(f) Polyurethane poly(meth)acrylate: It has the structure of polyhydric alcohol (meth)acrylate having a polyurethane bonding unit in the upper class, and usually contains bitroxyl group-containing (meth)acrylate, polyisocyanate, and polyhydric alcohol if necessary. It is synthesized by a method such as reacting with

For example, the addition reaction product of 2-hydroxylethyl (meth)acrylate or 2-hydroxypropyl (meth)acrylate and diisocyanate, the addition reaction product of 2-hydroxylethyl (meth)acrylate, diisocyanate, and dihydric alcohol, etc. Corresponds to an example.

(g) Polyamide poly(meth)acrylate; It has the structure of polyhydric alcohol (meth)acrylate having a polyamide bonding unit in the main chain, and is usually a polyamide-type polycarboxylic acid and a droxy group-containing (meth)acrylate or It is synthesized by reacting an epoxy group-containing (meth)acrylate or by reacting a polyamide-type polyhydric alcohol with (meth)acrylic acid.

For example, a reaction product of a polyamide-type polycarboxylic acid obtained by the reaction of ethylenediamine and phthalic acid and 2-hydroxyethyl (meth)acrylate or glycidyl (meth)acrylate corresponds to this example.

(h) Polysiloxane poly(meth)acrylate; It has a (meth)acrylate structure of a polyhydric alcohol with a polysiloxane bonding unit in the main chain, and (meth)acrylate is usually added to a polyhydric alcohol with a polysiloxane bonding unit. It is synthesized by a method such as a reaction.

(i) Vinyl-based or diene-based low polymer having (meth)acryloyloxy groups in the side chain and/or terminal: Ester bond, urethane bond, amide bond in the side chain or terminal of the vinyl-based or diene-based low polymer , has a structure in which (meth)acryloyloxy groups are bonded via an ether bond or the like. Low polymers that usually have hydroxy groups, carboxyl groups, epoxy groups, etc. in side chains or terminals,
(meth)acrylic acid, carboxyl group-containing (meth)acrylate, and hydroxyl group-containing (meth)acrylic acid, which are reactive with these groups.
It is synthesized by reacting meth)acrylate, epoxy group-containing (meth)acrylate, isocyanate group-containing (meth)acrylate, amino group-containing (meth)acrylate, etc.

For example, there may be mentioned a reaction product obtained by reacting a copolymer of (meth)acrylic acid and another vinyl monomer with glycidyl (meth)acrylate.

In addition, crosslinkable oligomers belonging to this system generally tend to become highly viscous or solid as the molecular weight increases, so they can be used by being dissolved in a liquid low viscosity monomer (crosslinking monomer) as described later, or Alternatively, it is preferable to use a liquid oligomer with a low molecular weight (usually a number average molecular weight of 3000 or less).

(j) Modified products of the crosslinkable monomers described in (a) to (i) above; It is a modified product modified by reacting with an acid chloride, an acid anhydride, an isocyanate, or an epoxy compound.
This is disclosed in Japanese Patent Laid-Open No. 128994, Japanese Patent Application Laid-Open No. 128088-1988, and the like.

The compounds are as follows.

i) CH2=CH-Coo-Cn H2n++ However, n is an integer from 1 to 12 ji) cH2=ct+-coo (CH2(:H2O
) RR=CnH2ns, - where n is an integer from 1 to 12 1ii) to H2=CH-1;DO(C8,CH20
)2RR=Co)(2ns1- where n is an integer from 1 to 12 iv) ii) and i iii) -(:82CH20-
CH stubbornness.

-C8, -(:)l-0-frequently changed v ) CH
2= CHCOOX OHCH3 X = -CH2(:H2-1-CH2(:)I-(:
H2 (:H-0- CH3 vi) Other tetrahydrofurfuryl acrylate, dicyclobentadienyloxyethyl acrylate, hydrogenated dicyclobentadienyloxyethyl acrylate vii) CH3 CH2= C-COOR'R' : -CH2CH20H5 - CH2CHCHs τ H CH3 viij) N-vinylpyrrolidone iX) Isovinyl acrylate, dicyclopentadienyl acrylate, hydrogenated dicyclobentadienyl acrylate They can be used alone or in an appropriate mixture depending on the disk structure and the like.

Optical ffi polymerization initiator Necessary when curing with external radiation (not required for electron beam curing), examples include benzoin alkyl ether, benzyl ketal, acetals, acetophenone derivatives, benzophenone derivatives, xanthone derivatives, Examples include benzaldehyde derivatives.

Specific examples of compound E include benzoin ethyl ether, benzoin isopropyl ether, hendiin isobutyl ether, benzophenone, pencil, 2,
2-dimethoxy-2-phenylacetophenone, 2,2
-dimethoxy-2-hydroxyacetophenone, diphenyl disulfide, 2-hydroxy-2-propiophenone, 4.4゛ -hisdiethylaminobenzophenone, dimethylaminohenzaldehyde, ethyl-4゜4゛
-Hisdimethylaminobenzophenone, ethyl anthraquinone, 2-chlorothioxanthone, etc. can be mentioned. These sensitizers can be used alone or in appropriate combinations.

Moreover, a silane coupling agent can be used if necessary. Examples of the silane coupling agent include epoxysilane-based silane coupling agents, such as γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, aminosilane-based silane coupling agents, For example, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane,
-Aminoethyl-γ-aminopropylmethyldimethoxysilane, vinylsilane-based silane coupling agents, such as γ-methacryloxypropyltrimethoxysilane, are preferred.

In the present invention, a fluorine-containing resin or a fluorine-containing monomer is added to a solution (ultraviolet curable resin) containing the above oligomer and monomer to prepare a coating solution for forming an antireflection layer.

Examples of the fluorine-containing resin include so-called fluororesins such as polymers, copolymers, or block polymers that are soluble in organic solvents and contain fluorine-containing monomers as polymerized units, and fluorine-modified resins. can. Examples of fluororesins that are polymers include polytetrafluoroethylene, polychlorotrifluoroethylene,
Examples include polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, and fluoroolefin-vinylyether covalent metal.

Although some fluorine-containing resins such as the above-mentioned fluororesins are soluble in specific organic solvents, such as polyvinylidene fluoride, they are generally insoluble in organic solvents, and include copolymers, block polymers, graft polymers, and modified polymers. By introducing other components as a resin, it can be made soluble in the organic solvent. Preferred examples include a comb-shaped graft polymer comprising a fluorine-containing acrylic monomer and a methacrylic acid ester, a fluoroolefin-vinyl ether copolymer, polyvinylidene fluoride, and a fluorine-containing epoxy resin as the fluorine-modified resin.

Specific examples of the above include Macromer F-3 (manufactured by Toagosei Chemical Industry Co., Ltd.), which is a comb-shaped graft polymer, and Lumiflon L, which is a fluoroolefin vinyl ether copolymer.
F-100, LF-200 (manufactured by Asahi Glass), Teflon AF-1600 (manufactured by DuPont), which is tetrafluoroethylene bis-2,2-trifluoromethyl-4,5-difluoro-1,3-dioxole ), etc. A dispersion type of fluororesin may also be used if it can be coated.

Generally, the above fluorine-containing resin is treated with an organic solvent (for example, methyl cellosolve is used for a comb-shaped graft polymer, or N-methyl-2-pyrrolidinone is used for polyvinylidene fluoride).
A solution containing the oligomer and monomer is added to the solution containing the oligomer and monomer to prepare a coating solution for forming an antireflection layer.

The solvent for dissolving the fluorine-containing resin described in L can be appropriately determined and used in consideration of the dissolving power of the solvent for the resin used. Such solvents include esters such as ethyl acetate, butyl acetate, and cellosolve acetate, cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve, ketones such as methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone, dichloromethane, 1,2-dichloroethane, and chloroform. halogenated hydrocarbons such as tetrahydrofuran, ethers such as ethyl ether, dioxane, ethanol, n
- Alcohols such as propatool, isopropatool, n-butanol, amides such as dimethylformamide,
Examples include fluorocarbon solvents such as 2,2,3°3-tetrafluoropropanol, N-methyl-2-pyrrolidinone, and the like.

The ratio of the fluorine-containing resin to the monomer and/or oligomer having a polymerizable double bond is preferably in the range of 2:298 to 70:230, more preferably 2:98 to 60: It is in the range of 40. In addition, the fluorine-containing resin soluble in the ino solvent of the present invention is
It means a resin capable of dissolving 0.01 g or more in 100 g of the solvent used for coating.

The coating solution for forming an antireflection layer of the present invention can be prepared by adding a fluorine-containing monomer having a polymerizable double bond to a solution (ultraviolet curable resin) containing the above oligomer and monomer. In the fluorine-containing monomer, the polymerizable double bond is numerically an acryloyl group or a methacryloyl group, and preferably the ester side chain is a fluorinated alkyl group. Examples of the fluorine-containing 4f monomer that can be used in the present invention include the following F monomers.

(] ) CH2-C(CH3) C00Ct1□C
F3(2) to 112=CIICOOCR2CF3(3
) Ct(2-C(Ctb) C00Ct+□(CF
2) 2F (4) CH2- (:00GHz (CF2
) 2F(5) GH2=(:(CH3)C00CH
z (CF2):IF(6) (7) (8) (9) (lO) (II) (12) (:H2J: (CL)COO(CH2) 2 (CF
z)aF(:Hz-CHCOO((:L)2(CF2)
aFCH2”C(C)+3) GOOCH2(CF2)
2HCH2-CHCOOCH2(CF2)28(:)1
2-C(1;H3)COO(:)Iz (II:Fz)
A coating solution for forming an antireflection layer is prepared by adding JCH2''CHCOOCH2(CF2)4Hmer and a monomer to a solution containing the monomer.Since the above monomer is usually in liquid form, it can be added as is, but an organic solvent (preferably A solution dissolved in a fluorine-based solvent (such as fluorine alcohol) may be added.Also, the ratio of the fluorine-containing monomer to the monomer and/or oligomer other than the fluorine-containing monomer is 2=98 to 70: It is preferably in the range of 30, more preferably 5=95-60:
The range is 40.

The coating liquid for forming an antireflection layer, which is prepared as described above and consists of the oligomer and monomer and a fluorine-containing resin or a fluorine-containing monomer, is coated on the surface of the substrate on which the recording layer is not provided. Ru. In addition, various additives such as an organic solvent, an antistatic agent, an antioxidant, and a UV absorber may be further added to the coating liquid containing the L oligomer and monomer depending on the purpose. Adding an antistatic agent such as a conductive material is effective in preventing the adhesion of dust and the like.

The above coating liquid should be applied to the surface of the substrate without a recording layer using coating methods such as spin code, dip coating, extrusion coating, etc. (after drying if it contains an organic solvent), and then cured by irradiating it with ultraviolet rays. It can be formed by

When the above coating liquid is cured with ultraviolet rays, the coating layer is cured by irradiating ultraviolet rays from a distance of 1 to 100 cm for 0.1 to 60 seconds using a high-pressure mercury lamp to form an antireflection layer. can do. When curing with electric Y° rays, an electron accelerator such as a linear accelerator or a hump graph accelerator is used.

The antireflection layer of the present invention may contain other resins in addition to the ultraviolet curable resin, fluorine-containing monomer, and fluorine-containing resin within a range that satisfies the E assignment refractive index, but generally the refractive index becomes high. This makes it difficult to obtain a sufficient antireflection effect. Moreover, the surface becomes easily scratched and the protective effect is reduced.

The substrate -1- has a tracking groove or an address D.
A pre-groove layer and/or a pre-pit layer may be provided for the purpose of forming unevenness representing information such as """. As a material for the pregroove layer, etc., a mixture of at least one monomer (or oligomer) of acrylic acid monoester, diester, trinisder, and tetraester and a photopolymerization initiator can be used.

The pre-groove layer is formed by first coating a mixture of the above acrylic acid ester and polymerization initiator on a precisely made type I (stambar), and then coating the substrate on top of this four-liquid layer. After being placed, the liquid layer is cured by irradiation with ultraviolet rays through the substrate or the mother mold, thereby fixing the liquid phase to the substrate. Next, by peeling the substrate from the mother mold, 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 is provided on the substrate (or pregroove layer, etc.) on the side where the antireflection layer is not provided.

Examples of metal materials used for the recording layer include Te, Z
Mention may be made of metals such as nsI nsSnsZr%AIL, Cu and Ge; metalloids such as Bi, As and Sb; semiconductors such as Ge and Si; and alloys thereof or combinations thereof. Compounds such as sulfides, oxides, borides, silicon compounds, carbides, and nitrides of these metals or semimetals; and mixtures of these compounds and metals can also be used in the recording layer. A polymer compound generally used for phase change recording may also be used.

The recording layer can be formed on the substrate-L or the intermediate coating layer by using the above recording material by a method such as vapor deposition, sputtering, or ion blasting. The polymer compound etc. can be provided by coating. If desired, an undercoat layer may be interposed below the intermediate layer. The recording layer may be a single layer or a multilayer, but its R thickness is generally in the range of 0.0 mm to 5500 mm in view of the optical density required for optical information recording.

When the material of the recording layer is a dye, examples of the dye used in the present invention include cyanine dyes such as imidazoquinoxaline dyes and indolizine dyes, phthalocyanine dyes,
Bylylium/thiopyrylium dyes, azulenium dyes, squarylium dyes, metal complex dyes with Ni, Cr, etc., naphthoquinone/anthraquinone dyes, indophenol dyes, indoaniline dyes, triphenylmethane dyes, Examples include allylmethane dyes, merocyan dyes, oxonol dyes, aminium/diimmonium dyes, and nitroso compounds.

Below, the formation of the margin pigment layer involves adding the above pigment, optionally a binder,
Dissolving a metal complex dye or aminium/diimmonium dye (quencher) 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. I can do it.

Solvents for preparing the dye coating solution listed in L include esters such as ethyl acetate, butyl acetate, and cellosolve acetate, ketones such as methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone, and 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, and fluorocarbons such as 2.2.3.3-tetrafluoropropanol. Examples include solvents. 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. .

Depending on the purpose, various additives such as antioxidant QL, UV absorber, plasticizer, lubricant, etc. may be added to the coating liquid.

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,
Synthetic polymeric materials such as polyvinyl alcohol, chlorinated polyolefins, epoxy resins, butyral resins, rubber derivatives, and initial condensates of thermosetting resins such as phenol-formaldehyde resins can be mentioned.

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 dye layer, the ratio of the dye to the binder is generally 0.01 to 99% (weight ratio).
It is preferably in the range of 1.0 to 95% (weight ratio).

The dye layer may be a single layer or a multilayer, but its layer thickness is generally in the range of 100 to 5,500X, preferably 200X.
It is in the range of ~3000.

A reflective layer may be provided on the recording layer. The light reflective material that is the material of the reflective layer is a material that has a high reflectance to laser light, and examples thereof include Mg, Se, etc.
, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo
, W., MnsRe.

Fe, Co, Ni, Ru, Rh, Pd, Ir.

Pt, Cu, Ag, Au, ZnsCd, Al1, Ga,
Mention may be made of metals and metalloids such as InsSi, Ge, Te, Pb, Po, SnsBi. Among these, preferred are AiL, Au, 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 substrate by, for example, vapor deposition, sputtering, or ion-blating the light-reflecting material described above. The thickness of the reflective layer is generally in the range of 100 to 3000 mm.

A protective layer may be provided on the reflective layer-L.

Examples of materials used for the protective layer include Sins5in2. Si3N4, MgF2, SnO
2nd place can be mentioned. In addition, as organic substances,
Examples include thermoplastic resins, thermosetting resins, UV curable resins, etc., with UV curable resins being preferred.

The protective layer can be formed, for example, by laminating a film obtained by extrusion of plastic onto a protective layer made of a resin soluble in a saturated hydrocarbon solvent via an adhesive layer. Alternatively, it may be provided by methods such as vacuum deposition, sputtering, and coating. In addition, in the case of thermoplastic resins and thermosetting resins, it can also be formed by dissolving these in an appropriate solvent to prepare a coating solution, then applying this coating solution and drying. . In the case of an ultraviolet curable resin, it may be formed by preparing a coating liquid as it is or by dissolving it in an appropriate solvent, applying this coating liquid, and curing it by irradiating it with UV light in the same manner as above. can. As the ultraviolet curable resin, the monomers, oligomers, etc. used in the antireflection layer can be used. In these coating solutions,
Furthermore, various additives such as antistatic agents, antioxidants, and UV absorbers may be added depending on the purpose.

The layer thickness of said further protective layer is generally in the range 0.1-100 μm.

Furthermore, the optical disc may be protected by covering it with a resin film instead of the protective layer.

In the present invention, the information recording medium may be a single board having the above-mentioned structure, or alternatively, two substrates having the above-mentioned structure may be placed facing each other so that the reflective layer is on the inside, and adhesive or the like is used. By joining, a laminated type recording medium can also be manufactured.

Further, the antireflection layer of the present invention is provided for the purpose of preventing reflection of the substrate when laser is irradiated from the substrate side. Therefore, the present invention can be applied to any information recording medium as long as it is possible to form an antireflection layer and obtain the same effect. Such information recording media include read-only type,
It can be applied to any type of medium, such as write-once (DRAW) type, rewritable type, magneto-optical, etc., regardless of whether it is recordable or not, or the type of recording layer. Moreover, the shape of the medium may be any, such as an optical disk, an optical card, an optical disc, or a flexible disk.

Recording on the information recording medium is performed, for example, as follows.

First, while rotating the information recording medium at a constant linear velocity or constant angular velocity, a recording light such as a semiconductor laser beam is irradiated from the substrate side to the pregroove group to generate an EFM signal of CD format. Signals are formed in various shapes in the recording layer of the group (bits in the recording layer in the case of a metal recording layer, cavities at the interface between the dye recording layer and the reflective layer in the case of a dye recording layer and a reflective layer, etc.). Record by doing. Generally, recording light is 750~
A semiconductor laser beam with an oscillation wavelength in the range of 850 nm is used. Generally recorded with a laser power of 1-15 mW.

During recording, tracking control is performed using the tracking pre-groove by a push-pull method or the like. Information is recorded in groups of pregrooves or on lands between groups.

Information can be reproduced using a three-beam method, for example, by rotating the recording medium at the same constant linear velocity or constant angular velocity as described above, irradiating laser light such as a semiconductor laser from the substrate side, and detecting the reflected light. Information can be reproduced while performing tracking control.

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

[Example 1] A coating liquid was prepared by dissolving 1.7 g and 0.17 g of 104 in 100 ml of 2,2,3,3-tetrafluoropropanol while applying ultrasonic waves for 1 hour.

A disc-shaped polycarbonate substrate provided with a pregroove (outer diameter: 120 mm, inner diameter: 15 mm, thickness: 1.
2mm, track pitch = 1.6μm, group depth: 800X, group position two radius 45mm ~ 116mm
(range) E, coating of the dye coating solution was started at a rotational speed of 200 rprn by the spin code method and maintained for 5 seconds.

Gradually reduce the rotation speed for 30 seconds and reach a final rotation speed of 1000.
The dye recording layer was stopped at the rpm and then dried to form a dye recording layer having a layer thickness of 1300 in each group.

Ar
Sputtering was performed under conditions of a pressure of 2 Pa and a power of 200 W to form a reflective layer with a layer thickness of 1300×.

Furthermore, ultraviolet curing resin (product name: 3070) is applied on the reflective layer.
, manufactured by Three Bond ■) using the spin code method at a rotation speed of 2.
Start application at a speed of 00 rpa+ and maintain for 5 seconds,
After 30 seconds while gradually increasing the rotation speed, the final rotation speed is 1000.
The coating layer was stopped at the rpm, and then the coated layer was irradiated with ultraviolet light (200W 7cm'' mercury lamp for 10 seconds) to form a protective layer made of ultraviolet curable resin with a layer thickness of 2 μm.

1) Apply the following coating solution to the opposite surface of the substrate on which the recording layer described in 2 was not provided using a spin code method at a rotation speed of 200.
Start application at the speed of RPVA, maintain it for 5 seconds, and gradually increase the rotation speed for 30 seconds to a final rotation speed of 1000 r.
pm, and then the coating layer was irradiated with ultraviolet light (200 W/cm 2 mercury lamp for 10 seconds) to form an antireflection layer with a layer thickness of 1400×.

--Stop Pzu Application- Ultraviolet curable resin (trade name: UR-4502, manufactured by Hishishi Ion ■) 4g Fluorine element F-containing graft polymer (trade name: Macromer F-3, manufactured by Toagosei Chemical Industry ■) 1g Methyl ethyl ketone
20ml methyl cellosolve
80 ml However, the above coating liquid was prepared by first dissolving the fluorine atom-containing graft polymer in methyl ethyl ketone and then mixing it with other components.

In this way, the reflection adjusting layer, the dye recording layer,
An information recording medium (see FIG. 2) was produced in which a reflective layer and a protective layer were provided, and an antireflection layer was provided on the back side of the substrate.

[Example 2] An information recording medium (see Figure 2) was prepared in the same manner as in Example 1, except that the coating liquid for forming the antireflection layer was changed to the following composition and an antireflection layer was formed. Manufactured.

`` Application for I stop ≦゛ Ultraviolet curable resin (product name: UR-4502, manufactured by Hishishi Ion ■) 4g β-(perfluorooctyl) ethyl acrylate (product name Nirite Ester FA-108, manufactured by Kyoeisha Yushi Kagaku Kogyo ■ made)
1g methyl cellosolve
100 m1 [Example 3J An information recording medium (see Figure 2) was prepared in the same manner as in Example 1, except that the coating liquid for forming the antireflection layer was changed to the following composition and an antireflection layer was formed. Manufactured.

Stop 5 1' Ultraviolet curing resin (product name: UR-4502, manufactured by Mitsubishi Rayon ■) 4g polyvinylidene fluoride (product name: kynar, manufactured by Renssalt Chemical)
IgN-methyl-2-pyrrolidinone 20 ml Methyl cellosolve 80 ml However, the above coating solution was prepared by first dissolving polyvinylidene fluoride in N-methyl-2-pyrrolidinone and then mixing it with other components.

Comparative Example 1 An information recording medium (see FIG. 2) was produced in the same manner as in Example 1 except that the antireflection layer was provided as described below.

1- MgF2 was vacuum-deposited on the surface of the opposite side of the substrate on which the recording layer was not provided, at a pressure of 2×1O-3P a
11 anti-reflection layers with a thickness of 130 mm were formed by vapor deposition under the following conditions.

[Comparative Example 2] An information recording medium was prepared in the same manner as in Example 1 except that the coating liquid for forming the antireflection layer in Example 1 was changed to the composition shown below to form an antireflection layer (see Figure 2). was manufactured.

k Parallel motion i 2 type shadow 1 PL Amakari ultraviolet curable resin (product name: UR-4502, manufactured by Mokushi Ion ■) 4 g methyl cellosolve 50 ml [Comparative example 3] In Example 1, the antireflection layer was changed as follows. An information recording medium (see FIG. 2) was produced in the same manner as in Example 1 except that the anti-reflection layer 1) was provided.

On the opposite surface of the substrate where the recording layer was not provided,
Polytetrafluoroolefin (PTFE) was deposited by RF sputtering under conditions of Ar pressure of 2 Pa and power of 500 W to form an antireflection layer with a layer thickness of 1400 i.

[Reference Example 1] An information recording medium was manufactured in the same manner as in Example 1 except that the antireflection layer was not provided.

The refractive index of the polycarbonate substrate used in Section E and the formed antireflection layer was measured as follows.

For the antireflection layer, leave the polycarbonate substrate as it is, and form a thin layer (500 to 1500X) on a glass plate by coating each material as described above or by sputtering, measure the reflectance and transmittance, and calculate the refraction. The rate was calculated.

As a result of the above, the refractive index of the polycarbonate substrate is 1.58.
, the antireflection layer of Example 1 is 1.48, the antireflection layer of Example 2 is 1.45, the antireflection IL layer of Example 3 is 145, the antireflection IF layer of Comparative Example 1 is 1.38, The antireflection layer of Comparative Example 2 had an antireflection value of 1.50, and the antireflection layer of Comparative Example 3 had an antireflection value of 1.35.

[Evaluation of information recording medium] Regarding the information recording medium obtained above, an oscillation wavelength of 780
EFM measurements of the CD format were recorded five times using a laser with a wavelength of 100 nm at recording laser power (recording power) of 7 mW and linear velocity of 1.3 m/sec.

Using a CD player modified so that a reproduction signal and a track error signal can be obtained, the -hrrer recording signal- was reproduced using a laser with an oscillation wavelength of 780 nm and a reproduction power of 0.5 mW.

1) Group reflectance (%) A group of unrecorded portions was irradiated with a laser, and a reproduction signal detection sensor detected the amount of reflected light relative to the amount of incident laser light, and was determined from the detected output.

2) Track servo gain (dB). Tracking is performed by irradiating a group of Cu parts with a laser, and a 1 kHz disturbance is manually applied to the track signal, and the rack error signal obtained at that time is measured with a servo analyzer (SR200, manufactured by Ono Saiki). did. Relative values are expressed when Reference Example 1 is expressed as OdB.

3) Track the CI (error correction signal) error (F/sec) by irradiating a group of recorded parts with a laser, put it into playback mode, and count the number of C1 flags (F) output by the EFM decoder with a counter. C
It was expressed as the value obtained by dividing the I flag by the measurement time (seconds).

4) Coating Strength of Layer The surface of each antireflection layer was wiped 50 times using absorbent cotton impregnated with methanol. The degree of surface scratches caused by this was evaluated as follows.

AA: No scratches at all.

BB: A scratch with a length of about several mm was observed.

CC: A scratch or peeling with a length of 10 mm or more occurred.

The above measurement results are shown in Table 1.

Table 1 Group Track servo reflectance Gain (zero) (dB) Example 1 74 0.7 Example 2 76 1.0 Example 3 75 0.9 1 Air (F/sec) Film strength 13 AA 12 AA 13 AA Comparative example 1 77 1.4 20 8B Comparative example 2
72 0-5 13 AA Comparative Example 3 7
9 1.7 10 8B Reference Example 1 0 O, O B As is clear from Table 1 above, the substrate of the optical disk having the basic structure consisting of the substrate, recording layer, reflective layer and protective layer of Examples 1 and 2. An information recording medium with an antireflection layer provided on the back side using a simple coating method has higher reflectance and track servo gain, and has a smaller C1 error than Reference Example 1, which does not have an antireflection layer. It has become.

Moreover, compared to Comparative Example 1, in which the antireflection layer is a conventional vapor-deposited film of an inorganic compound, the antireflection layers of Examples 1, 2, and 3 of the present invention are not inferior in antireflection function (the track servo gain is slightly inferior). However, it is clear that it has manufacturing advantages and high strength.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of an example of the information recording medium of the present invention, respectively. 11.21: Substrate 12.22: Recording layer 13.23: Antireflection layer 24: Reflection layer 25: Protective layer

Claims (1)

[Claims] 1. Information in which a recording layer on which information can be written or read by a laser is provided on a substrate, and an antireflection layer is provided on the surface of the substrate on the side where the recording layer is not provided. In the recording medium, the antireflection layer is made of a cured product of a mixture of a monomer and/or oligomer having a polymerizable double bond and a fluorine-containing resin, and has the following formula (I): √n_s×0.8≦ A refractive index within a range that satisfies n≦√n_s×1.2(I) (where n_s represents the refractive index of the substrate, n represents the refractive index of the antireflection layer) and the following formula (II): λ/4n×0.9≦d≦λ/4n×1.1 (II) (However, λ represents the wavelength of the laser used during reproduction, n represents the refractive index of the antireflection layer, and d represents the antireflection layer. An information recording medium characterized by having a layer thickness within a range that satisfies the following. 2. In an information recording medium in which a recording layer on which information can be written or read by a laser is provided on a substrate, and an antireflection layer is provided on the surface of the substrate on which the recording layer is not provided, the reflection The prevention layer is made of a cured product of a mixture of a fluorine-containing monomer having a polymerizable double bond and another monomer and/or oligomer having a polymerizable double bond, and has the following formula (I): √n_s×0 .8≦n≦√n_s×1.2(I) (where n_s represents the refractive index of the substrate, n represents the refractive index of the antireflection layer) and the following formula ( II): λ/4n×0.9≦d≦λ/4n×1.1 (II) (where λ represents the wavelength of the laser used during reproduction, n represents the refractive index of the antireflection layer, and d represents the layer thickness of the antireflection layer).