JP2003263790A - Optical information recording medium and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical information recording medium in which warp is suppressed, and a manufacturing method therefor. <P>SOLUTION: In the method for manufacturing the optical information recording medium, where a laminated body is formed by forming a recording layer in which information recording is allowed by laser light having a wavelength of ≤500 nm on a substrate in which a group having a track pitch of 200-400 nm and a groove depth of 10-150 nm is formed and by laminating a cover sheet on the recording layer of the laminated body. The temperature before laminating the cover sheet is adjusted so that the temperature in lamination may be in the range of ±5°C. Humidity before laminating the cover sheet is adjusted so that the humidity in the lamination may be in the range of ±18% RH. The lamination is done after retaining the cover sheet under a temperature- adjusted and humidity-adjusted state for 10 minutes or longer. The optical information recording medium is manufactured by the manufacturing method. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium and a manufacturing method thereof, and more particularly to a write-once type optical information recording medium by a heat mode and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, an optical information recording medium (optical disk) capable of recording information only once with a laser beam has been known. This optical information recording medium is a write-once CD (so-called C
D-R), and its typical structure is such that a recording layer made of an organic dye, a light reflection layer made of metal such as gold, and a resin protective layer are laminated in this order on a transparent disk-shaped substrate. It is a thing. The recording of information on the CD-R is performed by irradiating the CD-R with laser light in the near infrared region (usually, laser light having a wavelength near 780 nm), and the irradiated portion of the recording layer emits the light. Information is recorded by absorption and local temperature rise, and physical or chemical changes (for example, formation of pits) that change the optical characteristics of the part. On the other hand, reading (reproduction) of information is also performed by irradiating the CD-R with laser light having the same wavelength as that of the recording laser light, and the optical characteristics of the recording layer change from the changed portion (recording portion). This is done by detecting the difference in reflectance with the unrecorded part (unrecorded part).

In recent years, there has been a demand for an optical information recording medium having a higher recording density. In response to such a demand, a write-once digital versatile disc (so-called DVD-R)
An optical information recording medium referred to as is proposed (for example,
"Nikkei New Media" separate volume "DVD", published in 1995). This DVD-R has a transparent disc shape in which the guide groove (pre-groove) for tracking the emitted laser light is formed with a narrow groove width of less than half of the CD-R (0.74 to 0.8 μm). A structure in which two discs in which a recording layer containing an organic dye, a light reflection layer, and a protective layer are laminated in this order on a substrate are bonded together with the recording layer inside, or a disc with the same shape as this disc. It has a structure in which a protective substrate and a recording layer are attached to each other with the recording layer inside. Recording and reproduction of information on the DVD-R is performed by irradiating visible laser light (usually, laser light having a wavelength in the range of 630 nm to 680 nm), which has a higher density than that of the CD-R. It is possible to record.

Recently, networks such as the Internet and high-definition TV have been rapidly spread. Also, HDT
V (High Definition Televisions)
Ion) is about to start airing soon. Under such circumstances, there is a need for a large-capacity recording medium capable of inexpensively and easily recording image information. Currently, the DVD-R plays a sufficient role as a large-capacity recording medium, but the demand for large-capacity and high-density recording is increasing, and it is necessary to develop a recording medium that can meet these demands. . Therefore, development of a recording medium having a larger capacity, which enables high-density recording with light having a shorter wavelength than that of the DVD-R, is being advanced.

For example, JP-A-4-74690, JP-A-7-304256, and JP-A-7-304257.
JP-A-8-127174 and JP-A-11-53.
No. 758, No. 11-334204, No. 11-
334205, 11-334206, 11-334207, 2000-43423.
No. 2000-108513, No. 2000-108513
-113504, 2000-149320, 2000-158818, and 200.
Japanese Patent Laid-Open No. 0-228028 discloses recording and reproducing information in an optical information recording medium having a recording layer containing an organic dye by irradiating a laser beam having a wavelength of 530 nm or less from the recording layer side toward the light reflecting layer side. A recording / reproducing method for performing the above is disclosed. In these methods, optical information recording provided with a recording layer containing a porphyrin compound, an azo dye, a metal azo dye, a quinophthalone dye, a trimethine cyanine dye, a dicyanovinylphenyl skeleton dye, a coumarin compound, a naphthalocyanine compound, etc. The medium is blue (wavelength 430 nm, 488 nm) or blue-green (wavelength 515 nm).
Information is recorded and reproduced by irradiating a laser beam of (nm).

Also, from the viewpoint of compatibility with the currently used CD-R system, an optical information recording medium capable of recording and reproducing with laser beams of two different wavelength regions has been proposed. For example, Japanese Patent Laid-Open Nos. 2000-141900, 2000-158816, and 2000-
No. 185471, No. 2000-289342, and No. 2000-309165 disclose a mixture of a dye used for CD-R and a dye used for DVD-R, which is used in the near infrared region around 780 nm. There has been proposed an optical information recording medium capable of recording and reproducing with any of the above laser light and visible laser light near 650 nm.

However, according to the study by the present inventor,
The optical information recording medium described in the above publication has a wavelength of 450
When recording information by irradiating a short wavelength laser beam of nm or less, the sensitivity required for practical use cannot be obtained, and at a level where other recording characteristics such as reflectance and modulation degree can be satisfied. It was found that no improvement was required. Particularly, in the optical information recording medium described in the above publication,
It was confirmed that the recording characteristics were deteriorated when a laser beam having a wavelength of 450 nm or less was irradiated.

Further, when the cover sheet, which is the outermost surface layer, is stuck on the recording layer when the optical information recording medium described in each of the above publications is manufactured, the temperature and humidity before and after the sticking are different from each other. If the difference is large, there is a problem in that the optical information recording medium is warped after being bonded and cannot be put to practical use.

[0009]

From the above, the present invention is
An object of the present invention is to provide an optical information recording medium in which the occurrence of warpage is suppressed and a manufacturing method thereof.

[0010]

The above object can be achieved by the present invention described below. That is, in the present invention, the track pitch is 200 to 400 nm and the groove depth is 10 to 150 nm.
A recording layer capable of recording information with a laser beam having a wavelength of 500 nm or less is formed on a grooved substrate to prepare a laminated body, and a cover sheet is attached on the recording layer of the laminated body to form optical information. A method for producing a recording medium, wherein the temperature before the pasting of the cover sheet is adjusted within a range of ± 5 ° C of the temperature at the time of pasting,
After the humidity before the pasting of the cover sheet is adjusted to be within a range of ± 18% RH of the humidity at the time of pasting, and after the cover sheet is held for 10 minutes or more in the temperature-controlled and humidity-controlled state. It is a method of manufacturing an optical information recording medium, which is characterized in that bonding is performed. Further, the present invention is an optical information recording medium manufactured by the above manufacturing method.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The optical information recording medium of the present invention is manufactured through a laminating step of laminating a cover sheet on the recording layer of a laminate having a recording layer and the like formed on a substrate. Hereinafter, the optical information recording medium of the present invention will be described in detail centering on the bonding step.

<Laminating Step> In the laminating step, as described above, the inside of the optical information recording medium such as the recording layer is protected on the recording layer of the laminated body in which the recording layer is formed on the substrate. In order to do so, it is a step of attaching a cover sheet as a cover layer. The attachment of the cover sheet and the laminate is preferably performed via an adhesive or a pressure-sensitive adhesive.

The cover sheet is not particularly limited as long as it is a transparent material, but is preferably polycarbonate, cellulose triacetate, polymethylmethacrylate,
It is preferably made of a material such as polyvinyl chloride. In addition, "transparent" means that the cover sheet is transparent enough to transmit recording light and reproducing light (transmittance: 90% or more). The cover sheet has a thickness of 0.03 to 0.
It is preferably in the range of 15 mm, and 0.05 to 0.
More preferably, it is in the range of 12 mm. By setting such a range, it is possible to easily handle the cover sheet in the step of attaching the cover sheet, and it is possible to obtain an effect that coma aberration can be suppressed.

The method of laminating the cover sheet on the recording layer of the laminate (when a layer such as a barrier layer is formed on the recording layer) is not particularly limited.

The temperature before attaching the cover sheet is
The temperature of the atmosphere at the time of bonding is adjusted within ± 5 ° C, and the humidity (relative humidity, the same below) of the atmosphere before bonding the cover sheet is ± 18 of the humidity at bonding. The humidity must be adjusted so as to be in the range of% RH, and the cover sheet must be kept for 10 minutes or more in the temperature-controlled and humidity-controlled state. Before sticking, if the cover sheet is not temperature-controlled or humidity-controlled for 10 minutes or more as described above, the cover sheet is not adapted to the temperature and humidity, so it is stuck in a state where it contracts or expands due to a sudden temperature or humidity change. Will be. As a result, the optical information recording medium may be warped or deformed after being bonded.

The temperature adjustment is preferably within a range of ± 4 ° C. of the temperature at the time of bonding, more preferably ± 4 ° C.
The range is 3 ° C., more preferably ± 2 ° C. On the other hand, the humidity control is preferably within a range of ± 15% RH of the pasting humidity, more preferably within a range of ± 10% RH, and further preferably 5% RH.
To be within the range. A preferable time for maintaining the temperature and humidity is 20 minutes or longer, preferably 30 minutes or longer,
It is more preferably 40 minutes or more. The upper limit of the holding time is preferably one month (720 hours), and 10
Day (240 hours) is more preferable, and 5 days (1
20 hours) is more preferable, and 1 day (24 hours) is particularly preferable.

Further, from the viewpoint of preventing deformation of the optical information recording medium, the laminated body has the same conditions as those of the cover sheet (range of temperature of ± 5 ° C. for bonding and ± of humidity for bonding).
It is preferable to control the temperature and humidity in the range of 18% RH).
In particular, it is preferable to hold the cover sheet at the same temperature and humidity, and the holding time is preferably equal to or longer than the cover sheet holding time.

The temperature for laminating is preferably 20 ° C. or higher, more preferably 22 ° C. or higher, further preferably 23 ° C. or higher. If the temperature is too high, the adhesive or pressure-sensitive adhesive may be denatured, the characteristics of the optical information recording medium may be changed, and warp may occur when the temperature is returned to room temperature, which is not preferable. Therefore, the upper limit of the temperature is preferably 50 ° C or lower, more preferably 40 ° C or lower, and further preferably 35 ° C or lower.

The humidity at the time of bonding is preferably 32% RH or more, more preferably 35% RH or more, and further preferably 38% RH or more. If the humidity is too high, condensation may form on part of the device,
Warping may occur when the temperature is returned to room temperature, which is not preferable. Therefore, the upper limit of the humidity is preferably 80% RH or less, more preferably 70% RH or less,
It is more preferably 65% RH or less.

It should be noted that the above-mentioned temperature and humidity when the cover sheet is stuck on the recording layer of the laminate are at least from the time when the cover sheet is started to be stuck on the recording layer to the time when the adhesive is applied after the sticking. Alternatively, it is the time until the adhesive is cured and the cover sheet is fixed on the recording layer.

As the adhesive, it is preferable to use UV curable resin, EB curable resin, thermosetting resin, etc.
It is preferred to use UV curable resins. The adhesive is applied, for example, in a predetermined amount on the laminated surface (recording layer, etc.) of the laminate, and after the cover sheets are laminated, the adhesive is evenly applied between the laminate and the cover sheet by spin coating. It is preferable to spread so as to be cured and cured. The amount of adhesive applied depends on the thickness of the finally formed adhesive layer.
Range of 0.1 to 100 μm, preferably 0.5 to 50 μm
It is adjusted to be in the range of m, and more preferably in the range of 10 to 30 μm.

When a UV curable resin is used as an adhesive, the UV curable resin is prepared as it is or is dissolved in an appropriate solvent such as methyl ethyl ketone or ethyl acetate to prepare a coating solution, which is supplied to the surface of the laminate from a dispenser. May be. Further, in order to prevent the manufactured optical information recording medium from warping, it is preferable that the UV curable resin forming the adhesive layer has a small curing shrinkage ratio. Examples of such a UV curable resin include "SD" manufactured by Dainippon Ink and Chemicals, Inc.
UV curable resin such as -640 "can be mentioned.

As the adhesive, acrylic adhesive, natural rubber, styrene-isoprene-styrene copolymer (S
IS), styrene-butadiene-styrene copolymer (S
A rubber-based pressure-sensitive adhesive such as BS) can be appropriately selected and used. The pressure-sensitive adhesive is preferably applied in advance on the bonding surface of the cover sheet. The amount of the adhesive applied is preferably similar to that of the adhesive.

By the above bonding step, the optical information recording medium in which the occurrence of warpage is suppressed and which can be sufficiently put into practical use is manufactured.

By the way, it is preferable that the laminate laminated with the cover sheet in the laminating step is manufactured through a recording layer forming step of forming a recording layer on the surface of the substrate on which the groove is formed. Here, a light reflecting layer forming step of forming a light reflecting layer between the substrate and the recording layer may be provided, or a step of forming various layers such as a barrier layer on the recording layer may be appropriately provided. Hereinafter, as a specific example, a light reflection layer on the substrate,
A method of manufacturing the laminated body having the recording layer will be described.

<Light-Reflecting Layer Forming Step> The light-reflecting layer forming step is a step of forming a light-reflecting layer made of a light-reflecting substance on the groove-formed surface of the substrate described later. As the substrate, various materials used as the substrate material of the conventional optical information recording medium can be arbitrarily selected and used. Specifically, glass; acrylic resin such as polycarbonate and polymethylmethacrylate; vinyl chloride resin such as polyvinyl chloride and vinyl chloride copolymer; epoxy resin; amorphous polyolefin; polyester;
Examples thereof include metals such as aluminum; and the like, and if desired, these may be used in combination. Among the above materials, amorphous polyolefin and polycarbonate are preferable, and polycarbonate is particularly preferable, from the viewpoints of moisture resistance, dimensional stability and low cost. The thickness of the substrate is 1.
It is preferably 1 ± 0.3 mm.

On the surface of the substrate, a guide groove for tracking or an unevenness (groove) representing information such as an address signal is formed. The track pitch of the pre-groove is 2
It is essential that the thickness is in the range of 00 to 400 nm, preferably 250 to 350 nm. Further, the depth of the pre-groove (groove depth) must be in the range of 10 to 150 nm, preferably 50 to 100 nm.
The range is. By setting the track pitch and groove depth as described above, conventional CD-R (compact disc) and DVD-R (digital versatile disc)
Higher recording density can be achieved.

For the purpose of improving the flatness and the adhesive force, the surface of the substrate on the side where a light reflecting layer to be described later is provided,
It is preferable to form an undercoat layer. Examples of the material for the undercoat layer include polymethylmethacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylolacrylamide, styrene / vinyltoluene copolymer, and chloro. Polymeric substances such as sulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate; silane coupling Surface modifiers such as agents. The undercoat layer is prepared by dissolving or dispersing the above materials in a suitable solvent to prepare a coating liquid, and then spin coating, dip coating,
It can be formed by coating the substrate surface by a coating method such as extrusion coating. The thickness of the undercoat layer is generally in the range of 0.005 to 20 μm, preferably 0.01 to 10 μm.

The light reflecting layer can be formed on the substrate by vapor deposition, sputtering or ion plating of a light reflecting substance having a high reflectance for laser light. The thickness of the light reflecting layer is generally 10 to 300 nm.
And the range of 50 to 200 nm is preferable. The reflectance is preferably 70% or more.

As a light-reflecting substance having a high reflectance, M
g, Se, Y, Ti, Zr, Hf, V, Nb, Ta, C
r, Mo, W, Mn, Re, Fe, Co, Ni, Ru,
Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, C
d, Al, Ga, In, Si, Ge, Te, Pb, P
Examples thereof include metals such as o, Sn, and Bi, semimetals, and stainless steel. These light-reflecting substances may be used alone, in a combination of two or more, or as an alloy. Preferred among these are Cr, Ni, Pt, Cu, Ag, Au, Al and stainless steel. Particularly preferably Au, A
g, Al or alloys thereof, most preferably Au, Ag or alloys thereof.

<Recording Layer Forming Step> The recording layer forming step is a step of forming a recording layer capable of recording information on the light reflecting layer with a laser beam having a wavelength of 500 nm or less. The recording layer preferably contains a dye as a recording substance. The dye contained in the recording layer is not particularly limited as long as it is a dye capable of recording information with a laser beam having a wavelength of 500 nm or less, and examples thereof include a cyanine dye, an oxonol dye, a metal complex dye, an azo dye, Examples include phthalocyanine dyes.

Further, JP-A-4-74690, JP-A-8-127174, JP-A-11-53758, JP-A-11-334204, and JP-A-11-33420.
5 publication, 11-334206 publication, 11-33 publication.
4207, JP-A-2000-43423, JP-A-2000-108513, and JP-A-2000-1.
The dyes described in Japanese Patent No. 58818 and the like are also preferably used.

For the recording layer, a recording material such as a dye is dissolved in a suitable solvent together with a binder to prepare a coating solution, and then the coating solution is coated on the light reflecting layer formed on the surface of the substrate. It is formed by forming a coating film and then drying it. The concentration of the recording substance in the coating liquid is generally in the range of 0.01 to 15% by mass, preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, and most preferably Is in the range of 0.5 to 3 mass%.

Examples of the solvent for the coating liquid include butyl acetate, ethyl lactate, cellosolve acetate, and other esters; methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone, and other ketones; dichloromethane, 1,2-dichloroethane, chloroform, and other chlorinated hydrocarbons; dimethyl. Amides such as formamide; hydrocarbons such as methylcyclohexane; ethers such as tetrahydrofuran, ethyl ether, dioxane; alcohols such as ethanol, n-propanol, isopropanol, n-butanol diacetone alcohol; 2,2,3,3-tetrafluoro Fluorine-based solvents such as propanol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether; Rukoto can. The above solvents can be used alone or in combination of two or more in consideration of the solubility of the recording substance to be used. Various additives such as an antioxidant, a UV absorber, a plasticizer and a lubricant may be added to the coating liquid depending on the purpose.

When a binder is used, examples of the binder include gelatin, cellulose derivatives, dextran,
Natural organic high molecular substances such as rosin and rubber; polyethylene,
Hydrocarbon resin such as polypropylene, polystyrene, polyisobutylene, vinyl resin such as polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride / polyvinyl acetate copolymer, acrylic resin such as polymethyl acrylate and polymethyl methacrylate. , Polyvinyl alcohol, chlorinated polyethylene, epoxy resins, butyral resins, rubber derivatives, synthetic organic polymers such as initial condensates of thermosetting resins such as phenol / formaldehyde resins; When using a binder as the material of the recording layer,
The amount of the binder used is generally in the range of 0.01 times to 50 times the mass (mass ratio) of the recording substance, preferably 0.
It is in the range of 1-fold amount to 5-fold amount (mass ratio). The concentration of the recording substance in the coating liquid thus prepared is generally 0.
It is in the range of 01 to 10% by mass, preferably 0.1 to 5
It is in the range of mass%.

Examples of the coating method include a spray method, a spin coating method, a dipping method, a roll coating method, a blade coating method, a doctor roll method and a screen printing method. The recording layer may be a single layer or multiple layers. The layer thickness of the recording layer is generally in the range of 20 to 500 nm,
It is preferably in the range of 30 to 300 nm, more preferably in the range of 50 to 100 nm.

The recording layer may contain various anti-fading agents in order to improve the light resistance of the recording layer. A singlet oxygen quencher is generally used as the anti-fading agent. As a singlet oxygen quencher,
Those described in publications such as already known patent specifications can be used. As a specific example thereof, there is JP-A-58-1.
No. 75693, No. 59-81194, and No. 60.
No. 18387, No. 60-19586, and No. 6
0-19587, 60-35054, 60-36190, 60-36191,
No. 60-44554, No. 60-44555, No. 60-44389, No. 60-44390, No. 60-54892, No. 60-47069.
Japanese Patent Publication No. 63-209995, Japanese Patent Laid-Open No. 4-25
Japanese Patent Publication No. 492, Japanese Patent Publication No. 1-386080, and Japanese Patent Publication No. 6-26028, and German Patent 3503.
No. 99, and those described in the Chemical Society of Japan, October 1992, page 1141 and the like.

The amount of the anti-fading agent such as the singlet oxygen quencher used is usually in the range of 0.1 to 50% by mass, preferably 0.5 to 45% by mass, based on the amount of the dye. The range is more preferably 3 to 40% by mass, and particularly preferably 5 to 25% by mass.

After forming the recording layer, as a barrier layer,
You may form the layer which consists of oxides, nitrides, carbides, sulfides etc. which consist of any 1 or more of Zn, Si, Ti, Te, Sm, Mo, Ge etc. Examples of the material constituting the barrier layer may also be a hybrid of as ZnS-SiO _2. The barrier layer is sputtering,
It can be formed by vapor deposition, ion plating, or the like, and its thickness is preferably 1 to 100 nm.

As described above, a laminate having a light reflecting layer, a recording layer and the like is manufactured.

Next, a method of recording information on the optical information recording medium of the present invention and a method of reproducing the recorded information will be described. Recording of information on the optical information recording medium is performed as follows, for example. First, while rotating the optical information recording medium at a constant linear velocity, 500 nm for recording from the cover sheet side.
The following laser light is irradiated. By the irradiation of this laser light, the recording layer absorbs the light and locally raises the temperature, and a physical or chemical change (for example, pit formation) occurs, and the optical characteristics change. Information is recorded by this change in the optical characteristic.

As a laser light source having an oscillation wavelength of 500 nm or less, for example, a blue-violet semiconductor laser having an oscillation wavelength in the range of 390 to 415 nm, a central oscillation wavelength 42.
A 5 nm blue-violet SHG laser or the like can be used.
Further, in order to increase the recording density, the NA of the objective lens used for the pickup is preferably 0.7 or more, and 0.8
5 or more is more preferable.

On the other hand, in reproducing the recorded information, while rotating the optical information recording medium at the same constant linear velocity as described above, a laser beam having a wavelength equal to or shorter than that of the laser used for recording the information is covered. It can be performed by irradiating from the sheet side and detecting the reflected light.

[0044]

EXAMPLES The present invention will be specifically described with reference to the following examples, but the present invention is not limited thereto.

(Example 1) Thickness 1.1 mm, outer diameter 120
mm, an inner diameter of 15 mm, and a groove of a substrate made of an injection-molded polycarbonate resin having a spiral group (groove depth 30 nm, width 15 nm, track pitch 340 nm), and made of Ag by DC sputtering in an Ar atmosphere. A reflective layer (thickness 100 nm) was formed.

2 g of the dye A represented by the following chemical formula is added to 100 ml of 2,2,3,3-tetrafluoropropanol.
A dye coating solution was prepared by adding it to the inside and dissolving. The prepared dye coating liquid was spin-coated at a rotation speed of 300 to 4
It was coated on the reflective layer under the conditions of 23 ° C. and 50% RH while changing the speed to 000 rpm. Then, it was stored at 23 ° C. and 50% RH for 1 hour to form a recording layer (thickness 70 nm).

[0047]

[Chemical 1]

After the recording layer was formed, it was annealed in a clean oven. The annealing treatment was performed by holding the substrate on a vertical stack pole with a spacer interposed therebetween and holding it at 40 ° C. for 1 hour.

Thereafter, a barrier layer (thickness: 50 nm) made of ZnS / SiO ₂ (ZnS: SiO ₂ = 8: 2 (mass ratio)) was formed on the recording layer by RF sputtering to prepare a laminate. . The conditions for forming the barrier layer were as follows. Power ・ ・ ・ 4kW, Pressure ・ ・ ・ 2 × 10 ^-2 hPa, Time ・ ・ ・ 10 seconds

A cover sheet (outer diameter 120) made of the produced laminate and a polycarbonate coated with an adhesive on one side
mm, inner diameter 15 mm, thickness 80 μm) for 60 minutes under conditions of temperature control temperature of 25 ° C. and humidity control of 50% RH, and the pressure-sensitive adhesive coated surface and the barrier layer of the laminate are Under the same temperature and humidity conditions, the optical information recording medium was manufactured by installing and sticking to the inner peripheral boss. The thickness of the cover sheet and the layer made of the pressure-sensitive adhesive after pasting was about 100 μm. The temperature and humidity conditions were maintained until the cover sheet was fixed on the laminate.

(Examples 2 and 3) Examples 2 and 3 were prepared except that the laminated body and the cover sheet made of a polycarbonate coated with an adhesive on one side were stored under the temperature and humidity control conditions shown in Table 1 below. An optical information recording medium was produced in the same manner as in 1.

(Comparative Examples 1 to 4) Examples except that the produced laminate and a cover sheet made of a polycarbonate coated with an adhesive on one side were stored under the temperature and humidity control conditions shown in Table 1 below. An optical information recording medium was produced in the same manner as in 1.

Reference Example 1 The same as Example 1 except that the produced laminate and a cover sheet made of a polycarbonate coated with an adhesive on one side were stored under the temperature and humidity control conditions shown in Table 1 below. An optical information recording medium was produced in the same manner.

(Evaluation of Optical Information Recording Medium) With respect to the optical information recording media manufactured in Examples, Comparative Examples and Reference Examples, the warp state (tangential tilt value) of the entire optical information recording medium was measured by DLD4000 (Japan EM). (stock)
Manufactured). The measurement was performed twice immediately after the production of the optical information recording medium (within about 30 minutes) and one day after the production. The results are shown in Table 1 below.

[0055]

[Table 1]

From the results of Examples 1 to 3 in Table 1, by adjusting the temperature and humidity to the bonding temperature and humidity before bonding the cover sheet, not only immediately after the optical information recording medium was manufactured but also 1 An optical information recording medium having a warp (tangential tilt value) of 0.19 ° or less even after the lapse of days could be produced without any practical problems.

[0057]

According to the present invention, it is possible to provide an optical information recording medium in which the occurrence of warpage is suppressed and a manufacturing method thereof.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H111 EA03 EA12 EA22 EA25 EA31                       EA43 FA01 FA11 FB42 GA00                 5D029 JA04 LB01 RA03 RA06 RA27                       RA45 WB11 WB17                 5D090 CC01                 5D121 AA04 AA07 FF01 FF03 FF09

Claims (2)

[Claims] 1. A laminate is produced by forming a recording layer capable of recording information with a laser beam having a wavelength of 500 nm or less on a substrate having a track pitch of 200 to 400 nm and a groove depth of 10 to 150 nm. A method for producing an optical information recording medium by laminating a cover sheet on the recording layer of the laminate, wherein the temperature before laminating the cover sheet is within ± 5 ° C. of the laminating temperature. The temperature of the cover sheet is adjusted so that the humidity before bonding the cover sheet is within a range of ± 18% RH of the humidity at the time of bonding, and the cover sheet is in the temperature adjusted and humidity adjusted state. 10
A method for manufacturing an optical information recording medium, which is characterized in that the optical information recording medium is bonded after holding for more than a minute. 2. An optical information recording medium manufactured by the manufacturing method according to claim 1.