JPH07287866A - Optical recording medium and its production - Google Patents

Abstract

PURPOSE:To provide an optical recording medium with high massproductivity in which thermal design is improved and high density recording is possible, and to obtain a production method of an optical recording medium by which the optical recording medium having these advantages can be efficiently obtd. CONSTITUTION:After a dry photosetting film 2 in an unhardened state is formed on a light-transmitting substrate 1, a projecting part 4 having enough height for thermal insulation or a recessed part 5 having enough depth is press formed in this dry photosetting film 2 by using a silicon stamper at room temp. Then the unhardened dry photosetting film 2 is irradiated with UV rays to harden the dry photosetting film 2. Then a recording layer 3 is formed on the top of each projecting part 4 or the bottom of each recessed part 5. Thus, the obtd. optical recording medium realizes thermal insulation among each unit information region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium, and more particularly to an optical recording medium which suppresses thermal crosstalk during recording and erasing, enables high density recording and is excellent in productivity.

[0002]

2. Description of the Related Art In an optical recording medium in which information is recorded by the heat of condensed laser light, it is important to suppress thermal crosstalk during recording and erasing in order to increase the recording density.

As an optical recording medium in which thermal crosstalk during recording / erasing is suppressed, for example, as shown in FIG.
01 and a land 102, an active layer 104 capable of performing a reversible phase change, and a heat conductive dielectric on the active layer 104 and / or at least between the substrate 103 and the active layer 104. Light having a layer 105 and having a depth sufficient to provide thermal insulation between the adjacent groove 101 and land 102, specifically, a groove 101 having a depth of about 5,000 angstroms or more. A recording medium has been proposed (see Japanese Patent Laid-Open No. 4-141828).

Further, for example, as shown in FIG.
There is also known an optical recording medium in which a columnar bit recording cell 111 is formed in 10 and a recording layer 112 is formed on the upper surface of each bit recording cell 111 to achieve thermal insulation between the bit recording cells 111. .

On the other hand, as a method of molding a groove or a columnar bit recording cell in a substrate constituting an optical recording medium, generally, a pressure molding method using a nickel stamper, a molten resin in a mold including a stamper is used. Injection molding method in which it is solidified after being pressed under high pressure, or so-called 2 using a liquid resin that is cured by the energy of light such as ultraviolet rays.
The P (photo polymarization) method and the like are widely known.

[0006]

However, when the pressure molding method is used to mold the grooves or the bit recording cells in the substrate in the manufacture of the optical recording medium shown in FIG. 6 or 7, for example, the adjacent grooves 101 are not formed. If it is attempted to form the groove 101 or the bit recording cell 111 with a depth sufficient to provide thermal insulation with the land 102 or with a height sufficient to provide thermal insulation between the bit recording cells 111, a large addition is required. Since pressure is required, the substrate warps, and the mechanical properties of the substrate deteriorate.

Therefore, for example, in manufacturing the optical recording medium shown in FIG. 6 or 7, it is conceivable to adopt the injection molding method for molding the groove or the columnar bit recording cell in the substrate. When the method is adopted, it is difficult to obtain a substrate having good flatness in the optical recording medium shown in FIG. 6 due to curing shrinkage of the resin immediately after molding.
Further, the optical recording medium shown in FIG. 7 has a problem that it is difficult to form a small bit recording cell for high density recording. Further, even when the above-mentioned 2P method is adopted, it is not possible to obtain a substrate having good flatness because the curing shrinkage of the resin used for the 2P method is large, and since it takes time to mold, the manufacturing cost and mass productivity are improved. There is room for

Therefore, the present inventor has a groove (recess) having a sufficient depth for thermal insulation between the groove and the land, or a height sufficient for thermal insulation between the bit recording cells. As a result of intensive studies on an optical recording medium having protrusions (projections) capable of high-density recording, when a specific resin film is laminated on a substrate and recesses or protrusions are formed on this, molding accuracy and flatness are improved. It has been found that an optical recording medium having a substrate having excellent properties can be obtained, and an optical recording medium having such an advantage can be efficiently obtained by a specific manufacturing method.

The present invention has been made under such circumstances, and an object of the present invention is an optical recording medium having an improved thermal design, capable of high-density recording, and having high mass productivity, and such a recording medium. An object of the present invention is to provide an optical recording medium manufacturing method capable of efficiently obtaining an optical recording medium having advantages.

[0010]

In order to achieve the above object, an optical recording medium of the present invention comprises a light transmissive substrate, a dry photocurable film laminated on the light transmissive substrate, and the dry film. An optical recording medium having a recording layer laminated on a photo-curable film, wherein the dry photo-curable film has a depth in which a plurality of concave portions or convex portions each forming a unit information area are thermally insulated from each other. And a recording layer is formed on the bottom surface of each concave portion or the top surface of each convex portion, and the method for manufacturing an optical recording medium of the present invention is provided on a light-transmissive substrate. Forming a substrate with a dry photocurable film by laminating a dry photocurable film on the substrate, and stacking a silicon stamper on the exposed surface of the dry photocurable film in the substrate with the dry photocurable film. And forming a plurality of concave portions or convex portions, each of which serves as a unit information area, on the exposed surface of the dry photocurable film by pressure molding at room temperature in a depth or height such that they are thermally insulated from each other. A step of irradiating the dry photo-curable film with ultraviolet rays to cure the dry photo-curable film in a state where the silicon stamper is superposed, and separating the silicon stamper from the cured dry photo-curable film. The configuration includes a step and a step of forming a recording layer on the bottom surface of each concave portion or the upper surface of each convex portion.

[0011]

The optical recording medium of the present invention comprises a light transmissive substrate, a dry photocurable film laminated on the light transmissive substrate, and a recording layer laminated on the dry photocurable film. However, the dry photo-curable film laminated on the light-transmissive substrate is provided with a plurality of concave portions or convex portions each forming a unit information area with a depth or height such that they are thermally insulated from each other. A recording layer is formed on the bottom surface of the concave portion or the top surface of each convex portion. The dry photocurable film having such a recess or protrusion is
The viscosity at room temperature and in the uncured state is higher than the viscosity of the light transmissive substrate at room temperature, and higher than the viscosity of the liquid UV curable resin used in the conventional 2P method. Therefore,
Molding the heat-insulated recesses or protrusions into an uncured dry photocurable film does not require a large pressing force and thus does not lead to deterioration of the mechanical properties of the substrate and also causes curing shrinkage. Since it is small, the flatness of the substrate is high.
Therefore, in this optical recording medium, since a plurality of concave portions or convex portions each forming a unit information area are formed with a depth or height at which they are thermally insulated from each other and with high molding precision, high density recording is possible. Is possible.

Further, in the method for manufacturing an optical recording medium of the present invention, the optical transmissive substrate is directly formed without forming grooves or pits having a depth or a height sufficient to provide thermal insulation to each other. After stacking an uncured dry photocurable film on a transparent substrate, a silicon stamper is overlaid on the dry photocurable film and pressure-molded at room temperature to form recesses in the dry photocurable film. Alternatively, since the convex portion is formed, the pressure required for pressurization is lower than that when the concave portion or the convex portion is directly formed on the light transmissive substrate, and the mechanical characteristics of the light transmissive substrate are not deteriorated. Also,
Since the dry photocurable film has a small curing shrinkage, the flatness is not impaired. Moreover, a large pressurizing device is not required, and a heating device is unnecessary.

Furthermore, in the method of manufacturing the optical recording medium of the present invention, since the silicon stamper is used, the uncured dry photocurable film has a sufficient depth or height for thermal insulation. It is possible to accurately form the concave portion or the convex portion. Then, after irradiating such a dry photocurable film with ultraviolet rays to cure the dry photocurable film, a recording layer is formed on the bottom surface of each concave portion or the upper surface of each convex portion to form a unit information area. Because
The resulting optical recording medium solves the problem of thermal crosstalk during recording and erasing, and enables high density recording. Therefore, according to the method of the present invention, it is possible to efficiently manufacture an optical recording medium having an improved thermal design and capable of high density recording.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are explanatory views showing an example of the optical recording medium of the present invention.

The optical recording medium shown in FIG.
And a dry photo-curable film 2 and a recording layer 3. The dry photo-curable film 2 is provided with a plurality of columnar protrusions 4 having a height sufficient to perform thermal insulation. The recording layer 3 is formed on the upper surface of the convex portion 4.

On the other hand, the optical recording medium shown in FIG. 2 is also a laminated body of the light transmissive substrate 1, the dry photocurable film 2 and the recording layer 3, and the recesses 5 are mutually heated in the dry photocurable film 2. There are several with sufficient depth to insulate,
The recording layer 3 is formed on the bottom surface of each recess.

That is, in the optical recording medium shown in FIG. 1, a unit information area is formed by the convex portion 4 and the recording layer 3 provided on the upper surface thereof, and in the optical recording medium shown in FIG. And except that the unit information area is formed by the recording layer 3 provided on the bottom surface thereof,
Since both configurations are the same, both will be collectively described below.

As a material for forming the light-transmitting substrate 1, any material having light-transmitting property may be used. For example, polycarbonate (PC), polymethylmethacrylate (PMM).
Examples include resins such as A) and transparent materials such as optical glass. Among various transparent materials, polycarbonate (P
C) is preferably used because it has excellent environment resistance and dimensional stability.

This light transmissive substrate 1 is integrally formed by, for example, injection molding when the forming material is a resin, but is not limited to such an injection molding resin substrate, and is made of, for example, a resin sheet. It may be obtained by cutting or punching into a shape. Further, it may be formed by the 2P method.

The shape and size of the light transmissive substrate 1 are appropriately determined according to the application of this optical recording medium. The light transmissive substrate 1 is provided with a convex portion 4 having a height sufficient to perform thermal insulation with each other or a concave portion 5 having a depth sufficient to perform thermal insulation with respect to each other. The film 2 is laminated.

This dry photocurable film 2 is used at room temperature
The viscosity in the uncured state is lower than the viscosity of the light transmissive substrate 1 at room temperature, and it has a property of being cured by irradiation of ultraviolet rays, and substantially contains no solvent.

Specifically, the viscosity of the dry photocurable film 2 at room temperature / uncured state is usually from 3,500 to
400,000 poise, preferably 20,000-4
It is 10,000 poise. If the viscosity is less than 3,500 poise, it may become almost liquid and the film shape may not be maintained, or curing shrinkage may become excessive. On the other hand, when the viscosity exceeds 400,000 poise, the convex portion 4 having a height sufficient for thermal insulation is provided.
Alternatively, the pressure required to form the recess 5 having a sufficient depth for thermal insulation may be several tens of tons or more, which may cause deterioration of the mechanical characteristics of the light transmissive substrate 1 and the light transmissive substrate. In some cases, the adhesion to No. 1 is reduced and it cannot be put to practical use.

Such a dry photocurable film 2 is
It is formed of a photocurable resin composition that is converted into a high molecular weight polymer by crosslinking and / or polymerization, and examples of such a photocurable resin composition include a photopolymerizable photosensitive resin composition.

The photopolymerizable photosensitive resin composition contains an ethylenically unsaturated monomer, a photopolymerization initiator and a binder polymer. Here, as the ethylenically unsaturated monomer, for example, t-butyl acrylate, 1,5-
Pentanediol diacrylate, N, N-diethylaminoethyl acrylate, ethylene glycol diacrylate, 1,4-butanediol diacrylate, diethylene glycol diacrylate, 1,3-propanediol diacrylate, decamethylene glycol diacrylate, decamethylene glycol diacrylate Methacrylate,
1,4-cyclohexenediol diacrylate, 2,
2-dimethylolpropane diacrylate, glycerol diacrylate, tripropylene glycol diacrylate, glycerol triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, polyoxyethylated trimethylolpropane triacrylate, polyoxyethylated trimethylolpropane Trimethacrylate, 2,2-di (p-
Hydroxyphenyl) -propanediacrylate, 2,
2-di (p-hydroxyphenyl) -propane dimethacrylate, pentaerythritol tetraacrylate,
Triethylene glycol diacrylate, polyoxyethyl-2,2-di- (p-hydroxyphenyl) propane dimethacrylate, triethylene glycol dimethacrylate, polyoxypropyl trimethylolpropane triacrylate, ethylene glycol dimethacrylate, butylene glycol dimethacrylate 1,3-propanediol dimethacrylate, 1,2,4-butanetriol trimethacrylate, 2,2,4-trimethyl-1,3-pentanediol dimethacrylate, pentaerythritol tetramethacrylate, trimethylolpropane trimethacrylate, 1 , 5-pentanediol dimethacrylate and the like.

For example, these ethylenically unsaturated monomers may be used alone or in combination of two or more. The content of the ethylenically unsaturated monomer in the photopolymerizable photosensitive resin composition is usually 5 to 90% by weight, preferably 15 to 50% by weight.

Examples of the photopolymerization initiator include 9,10
-Anthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 2-methylanthraquinone, 2-
Ethylanthraquinone, 2-t-butylanthraquinone, octamethylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthrequinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-methyl-1,4. -Naphthoquinone, 2,3-dichloronaphthoquinone, 1,4-dimethylanthraquinone, 2,3-dichloronaphthoquinone, 1,4-dimethylanthraquinone, 2,3-dimethylanthraquinone, 2,3-diphenylanthraquinone, 2-phenylanthraquinone, Anthraquinone α-sulfonic acid sodium salt, 3-chloro-2-methylanthraquinone, retenquinone, 7,
Polynuclear quinones such as 8,9,10-tetrahydronaphthacenequinone, benzoin, pivaloin, acyloin ether, α-hydrocarbon-substituted aromatic acyloin, phenazine,
Examples thereof include oxazine, Michler's ketone, benzophenone and cyclohexadiene compound. For example, it is also preferable to use a sensitizer together with these photopolymerization initiators.

For example, these photopolymerization initiators may be used alone or in combination of two or more. The content of the photopolymerization initiator in the photopolymerizable photosensitive resin composition is usually 0.5 to 30% by weight, preferably 1 to 5% by weight.

As the binder polymer, for example, polymethyl methacrylate, polyethyl methacrylate,
Polyvinyl acetate, polyvinyl acetate / acrylate, polyvinyl acetate / methacrylate, ethylene / vinyl acetate copolymers, polystyrene polymers and copolymers, vinylidene chloride / acrylonitrile, copolymers of vinylidene chloride / methacrylate with vinylidene chloride / vinylidene acetate, polyvinyl chloride and copolymers, butadiene / butadiene Acrylonitrile, acrylonitrile / butadiene /
Styrene, methacrylate / acrylonitrile / butadiene / styrene copolymer, 2-chlorobutadiene-
1,3-polymer, chlorinated rubber, styrene / butadiene / styrene, styrene / isoprene / styrene block copolymer, epoxide containing acrylate group or methacrylate group, copolyester, polyamide, cellulose ester, cellulose ether, polycarbonate, polyvinyl acetal, poly Formaldehyde etc. are mentioned.

For example, these binder polymers may be used alone or in combination of two or more. The content of the binder polymer in the photopolymerizable photosensitive resin composition is usually 5 to 90% by weight, preferably 15 to 50% by weight. For example, the photopolymerizable photosensitive resin composition containing these components is Other components, such as a plasticizer, a thickener, an ultraviolet absorber, an antioxidant, a fluorescent bleaching agent, and a heat stability, within the range where the viscosity of the dry photocurable film 2 at room temperature / uncured state does not deviate from the above range. It may contain an agent, a release agent and the like.

The content of these components in the photopolymerizable photosensitive resin composition is usually 0 to 25 for the plasticizer.
% By weight, preferably 5 to 15% by weight, and other components are usually 0 to 5% by weight, preferably 1 to 4%.
% By weight.

As the photocurable composition for forming the dry photocurable film 2, in addition to the photopolymerizable photosensitive resin composition, for example, a photodimer type photosensitive resin composition or a photocrosslinking type photosensitive resin is used. A composition is mentioned.

The dry photo-curable film 2 is laminated on the light-transmissive substrate 1 in an uncured state, and thereafter, the convex portions 4 each forming a unit information area on the dry photo-curable film 2 in an uncured state. Alternatively, after the shape of the concave portion 5 is transferred to form the convex portion 4 having a height sufficient for performing thermal insulation or the concave portion 5 having a depth sufficient for performing thermal insulation, ultraviolet rays are irradiated. Hardened. Then, the dry photocurable film 2 and the light transmissive substrate 1 are adhered to each other by utilizing the adhesive force of the dry photocurable film 2. Therefore, in this optical disc, it is not necessary to provide an adhesive layer between the dry photocurable film 2 and the light transmissive substrate 1.

The thickness of the dry photocurable film 2 is usually 5 to 150 μm, preferably 10 to 60 μm. Further, the refractive index of the dry photocurable film 2 after photocuring is usually 1.40 to 1.60, and the difference from the refractive index of the light transmissive substrate 1 is preferably 0.05 or less. .

The height of the convex portions 4 and the depth of the concave portions 5 formed on the dry photocurable film 2 are both high enough to perform thermal insulation between adjacent convex portions or concave portions. Or depth is important.

Specifically, the height of the convex portion 4 is usually 0.
3 μm or more, preferably 0.5 μm or more, and the recess 5
Has a depth of 0.3 μm or more, preferably 0.5 μm or more. If the height of the convex portion 4 is less than 0.3 μm or the depth of the concave portion 5 is less than 0.5 μm, thermal insulation between adjacent convex portions 4 or concave portions 5 is not sufficiently performed,
The high-density recording suitability of the optical recording medium may deteriorate.

The distance between the adjacent convex portions 4 and the distance between the adjacent concave portions 5 is usually 0.1 to 0.5 μm,
It is preferably 0.1 to 0.3 μm. This interval is 0.
If it is less than 1 μm, the thermal insulation between the adjacent convex portions 4 or the adjacent concave portions 5 may not be sufficient. On the other hand, if the distance exceeds 0.5 μm, such an optical recording medium may not be suitable for high density recording.

As shown in FIG. 1 or FIG. 2, the recording layer 3 is provided on the upper surface of the convex portion 4 or the bottom surface of the concave portion 5, whereby a unit information area is formed. Examples of the material for forming the recording layer 3 include TbFeCo and GdFeCo / Tb.
Magneto-optical memory material such as Fe, Pt / Co, DyFeCo, Bi or Ce substituted garnet; Sn-Se-Te
System, Sb-Te system, In-Se system, Ga-Te system, Ge
-Te-based so-called phase change materials; organic dye films such as phthalocyanine-based dye films and naphthalocyanine-based dye films; Cu
TCNQ optical recording film; a liquid crystal polymer such as an acrylate polymer having a cyanobiphenyl group as a mesogen group.

The thickness of the recording layer 3 provided on the upper surface of each convex portion 4 or the bottom surface of each concave portion 5 differs depending on the forming material of the recording layer 3 and the like, so it is difficult to determine it uniformly. The thickness of the recording layer 3 made of a magneto-optical memory material is usually 0.02 to 0.1 μm, preferably 0.02 to 0.
It is about 08 μm.

The recording layer 3 may be further provided with a dielectric film and a protective film (both not shown) if necessary. When the dielectric film is provided, examples of the material for forming the dielectric film include ZnS, SiN, AlN, and SiO. The thickness of such a dielectric film is, for example, at a wavelength of 780.
When using a recording / reproducing laser beam of nm, 60 to 90n
It is about m. When the protective film is provided, examples of its forming material include epoxy resin, acrylic resin, silicone resin, urethane resin, and ethylene / vinyl acetate copolymer resin. It may also be a UV curable resin. The thickness of such a protective film is usually 10 to 10.
It is about 20 μm.

In the optical recording medium having the above-mentioned structure, the convex portion 4 or the concave portion 5 having a height sufficient for thermal insulation is formed on the dry photocurable film 2 laminated on the phototransparent substrate 1. Since the recording layer 3 is provided on the upper surface of the convex portion 4 or the bottom surface of the concave portion 5 to form the unit information area,
This optical recording medium has the advantages that the mechanical characteristics of the substrate are not deteriorated, the thermal insulation between the unit information areas is sufficiently performed, and high density recording is possible.

The optical recording medium having such advantages is efficiently manufactured by the method of the present invention described below.
3 and 4 are process diagrams showing an example of the manufacturing method of the present invention, and FIG. 5 is a process diagram showing an example of a manufacturing process of a silicon stamper suitably used in the manufacturing method of the present invention.

As shown in FIG. 3A, in this method, first, the dry photocurable film 2 is supplied from the film supply roll 51. Here, the dry photocurable film 2 is, for example, polyethylene terephthalate (PE
T) a base film 21 made of a film and a cover film 22 made of a polyethylene (PE) film, for example.
And is wound around the film supply roll 51 in the form of a laminated body of. This dry photocurable film 2 is a film in which one surface of the uncured dry photocurable film 2 exposed by winding the cover film 22 with the cover film take-up roll 52 faces the light transmissive substrate 1, for example. It is pulled out from the supply roll 51. The uncured dry photocurable film 2 thus drawn out is pressed by the overroll 53 and the underroll 54 in a state of being overlapped with the light transmissive substrate 1, and is uncured with the light transmissive substrate 1. Two dry photocurable films are laminated and pressure-bonded. The base film 21 laminated on one surface of the uncured dry photocurable film 2 has a silicon stamper 33 on the dry photocurable film 2.
Are peeled off at any stage before they are superposed.

Here, the dry photocurable film 2 to be used has a lower viscosity at room temperature and in an uncured state than that of the light transmissive substrate 1 at room temperature, and is cured by irradiation with ultraviolet rays. It has properties and is substantially free of solvent. Specifically, the viscosity of the dry photocurable film 2 at room temperature in an uncured state is usually 3,500 to 40.
10,000 poise, preferably 20,000-40,000
It is 00 poise. If the viscosity is less than 3,500 poise, it may become almost liquid and the film shape may not be maintained, or curing shrinkage may become excessive. On the other hand, when the viscosity exceeds 400,000 poise, the pressing force required to form the convex portion 4 or the concave portion 5 constituting each unit information area becomes several tens of tons or more, and the mechanical characteristics of the light transmissive substrate 1 deteriorate. In addition, the adhesive strength to the light-transmissive substrate 1 may be reduced and it may not be put to practical use.

Next, the laminated body of the light transmissive substrate 1 and the uncured dry photocurable film 2 obtained in the above process is
For example, by cutting along the broken line shown in FIG. 3B, the laminated body is formed into a predetermined shape of the optical recording medium, and unnecessary portions of the laminated body are removed.

After that, as shown in FIG. 3C, the laminate having the predetermined shape obtained in the above step is placed on the transfer base 31, and the position of the silicon stamper 33 is adjusted by using the position adjusting jig 32. I do.

Here, in the method of the present invention, the silicon stamper 33 is preferably used. Silicon stamper is used for dry photo-curable film 2 in uncured state.
This is because the transferability of the convex portion 4 having a sufficient height for thermal insulation or the concave portion 5 having a sufficient depth for thermal insulation is good.

The silicon stamper 33 as described above is manufactured as follows, for example, in the steps shown in FIG. First, as shown in FIG. 5A, a chromium (Cr) film 82 is formed on a glass substrate 81, a photoresist 83 is applied on the Cr film 82, and then an exposure process is performed.
Next, as shown in FIG. 5B, a photoresist development process and a Cr film etching process are performed to perform photomask 8 etching.
Create 4. Next, as shown in FIG. 5C, UV light is irradiated with the photomask 84 placed on the silicon wafer 86 coated with the photoresist 85,
After exposing the photoresist 85, a developing process is performed and then a reactive ion etching process is performed, so that a convex portion having a height sufficient for thermal insulation or a depth sufficient for thermal insulation is provided. A silicon stamper 33 having a negative shape of a recess is obtained.

For example, as shown in FIG. 3D, the silicon stamper 33 manufactured in this manner is aligned with the laminated body of a predetermined shape placed on the transfer base 31 and overlapped with it. , Between the over roll 61 and the under roll 62. The over-roll 61 and the under-roll 62 are a negative convex shape or concave shape formed on the uncured dry photocurable film 2 on the silicon stamper 33 by pressing the laminated body of a predetermined shape and the silicon stamper 33. Is accurately transferred to form a convex portion 4 having a sufficient height for thermal insulation or a concave portion 5 having a sufficient depth for thermal insulation. This transfer step is performed at room temperature, and the pressure is usually 0.5 to 50 kg / cm.
² , preferably 5 to 20 kg / cm ² .

The height of the convex portions 4 or the depth of the concave portions 5 thus formed and the distance between the adjacent convex portions 4 or the concave portions 5 are as described above. After that, FIG.
As shown in (a), the laminated body having a predetermined shape is taken out from the transfer base 31 with the silicon stamper 33 being overlaid thereon, and the uncured dry photocurable film 2 is exposed to ultraviolet rays from the light transmissive substrate 1 side. Irradiation is performed to cure the dry photocurable film 2.

Next, as shown in FIG. 4 (b), the silicon stamper 33 is separated from the laminate having a predetermined shape irradiated with ultraviolet rays as described above, and then, as shown in FIG. 4 (c). The recording layer 3 is provided on the upper surface of each convex portion 4 or the bottom surface of each concave portion (not shown) to form a unit information area.

The method of forming the recording layer 3 is appropriately determined according to the material for forming the recording layer. For example, when a magneto-optical memory material is used, a vacuum film forming method such as a sputtering method, an ion plating method, or a vapor deposition method is adopted.

Thereafter, if necessary, a dielectric film, a protective film, etc. are formed on the recording layer 3 by a conventional method. The optical recording medium manufactured in this way has a light-transmissive substrate 1.
There is no deterioration in the mechanical characteristics of, and the thermal insulation between the unit information areas is sufficiently performed, so that high density recording is possible. Therefore, according to this method, there is no deterioration in the mechanical properties of the substrate,
Moreover, it is possible to efficiently manufacture an optical recording medium which has improved thermal design and enables high density recording.

[0053]

The optical recording medium of the present invention comprises a dry photo-curable film laminated on a light-transmissive substrate, and the dry photo-curable film is provided with a convex portion or a heat-insulating film having a height sufficient for thermal insulation. Since a concave portion having a sufficient depth for insulation is formed and a recording layer is provided on the upper surface of each convex portion or the bottom surface of each concave portion to form a unit information area, mass productivity is high,
The mechanical characteristics of the substrate are not deteriorated, and thermal crosstalk between the unit information areas at the time of recording / erasing is suppressed, so that high density recording is possible.

The method of manufacturing the optical recording medium of the present invention is
Convex portion with sufficient height for thermal insulation or concave portion with sufficient depth for thermal insulation by using silicon stamper on uncured dry photocurable film on transparent substrate After transfer, the recording layer is formed on the upper surface of each convex portion or the bottom surface of each concave portion, so that the convex portion having a height sufficient for thermal insulation or the depth sufficient for thermal insulation is formed. The pressing force required to transfer the concave portion having a large thickness is small, the mechanical properties of the substrate are not deteriorated, and the flatness is not impaired by the curing shrinkage. Moreover, the molding accuracy of the convex portion or the concave portion is high. Therefore, according to the method of the present invention, there is no deterioration of the mechanical properties of the substrate, and a convex portion having a height sufficient for thermal insulation or a concave portion having a depth sufficient for thermal insulation is formed. It is possible to efficiently manufacture an optical recording medium having high accuracy and capable of high density recording.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of an optical recording medium of the present invention.

FIG. 2 is an explanatory diagram showing another example of the optical recording medium of the present invention.

FIG. 3 is a process drawing showing an example of the manufacturing method of the present invention.

FIG. 4 is a process drawing showing an example of the manufacturing method of the present invention.

FIG. 5 is a process drawing showing an example of a manufacturing process of a silicon stamper that can be suitably used in the manufacturing method of the present invention.

FIG. 6 is an explanatory diagram showing an example of a conventional optical recording medium.

FIG. 7 is an explanatory diagram showing another example of a conventional optical recording medium.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light transmissive substrate 2 ... Dry photocurable film 3 ... Recording layer 4 ... Convex part 5 ... Recessed part 33 ... Silicon stamper

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G11B 11/10 541 A 9075-5D (72) Inventor Kiyoro Fujii 2680 Nishihanawa, Tatomi-cho, Nakakoma-gun Yamanashi Address Pioneer Video Co., Ltd. (72) Inventor Naoto Kosasa 2680 Nishi Hanawa, Tatomi-cho, Nakakoma-gun Yamanashi Pioneer Video Co. Within the corporation

Claims (2)

[Claims] 1. An optical recording medium having a light transmissive substrate, a dry photocurable film laminated on the light transmissive substrate, and a recording layer laminated on the dry photocurable film. , The dry photocurable film is provided with a plurality of recesses or protrusions each forming a unit information area with a depth or height such that the recesses or protrusions are thermally insulated from each other. An optical recording medium having a recording layer formed on an upper surface thereof. 2. A step of laminating a dry photocurable film on a light transmissive substrate to form a substrate with a dry photocurable film, and an exposed surface of the dry photocurable film in the substrate with the dry photocurable film. Depth or height at which a plurality of recesses or protrusions, each of which serves as a unit information area, are thermally insulated from each other on the exposed surface of the dry photocurable film by stacking a silicon stamper on and press forming at room temperature. And a step of irradiating the dry photo-curable film with ultraviolet rays in a state where the silicon stamper is superposed on the dry photo-curable film, and a dry photo-curing process in which the silicon stamper is cured. And a step of forming a recording layer on the bottom surface of each concave portion or the top surface of each convex portion. Process for producing an optical recording medium according to.