JP2000339775A - Production of information recording medium and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to produce an information recording medium capable of corresponding to high density optical recording by flatly sticking two sheets of disk substrates which have an information recording layer on at least one side without distortion. SOLUTION: In this producing process, two sheets of disk substrates 3a, 3b between which photosetting adhesive 3c is interposed are flatly pressurized by using a pressurizing means 30, the pressurized disk substrates are irradiated with a first light, which can heat the disk substrates without hardening the photosetting adhesive 3c, from the first light irradiating means 10 and, thereby, the disk substrates are heated. After the temperature of the disk substrates attain the predetermined temperature, the disk substrates are irradiated with a second light, which can harden the photosetting adhesive 3c, from the second light irradiating means 9 and, thereby, the photosetting adhesive 3c is hardened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing an information recording medium capable of coping with high-density optical recording by laminating two disk substrates having an information recording layer on at least one side flat without distortion. Things.

[0002]

2. Description of the Related Art There are two conventional methods of bonding optical disks.
Can be roughly divided into two. One of them is to form an information recording layer on a polycarbonate disk by sputtering or the like, apply an ultraviolet curable resin by a spin coater method, form a protective film by irradiating ultraviolet rays, and manufacture a disk substrate. Applying a hot-melt type adhesive to the information recording layer side of two disk substrates (one of which may be a dummy disk substrate) using, for example, a roll coater; After applying by screen printing method, irradiate with ultraviolet rays or attach double-sided adhesive tape, adsorb the disk substrate on the top and bottom of the pressure device, align the disk substrate, and then press and bond Is the way. The other is to form an information recording layer on a polycarbonate disk by sputtering or the like, apply a UV curable resin or an electron beam curable resin between two disk substrates by a spin coater method, This is a method in which the resin is cured by beam irradiation and bonded. Further, as a bonding method other than the above, as described in Japanese Patent Application No. 4-19821,
A technique for bonding the adhesive while maintaining the viscosity of the adhesive constant by a heating means at the time of pressurization, and as described in Japanese Patent Application Nos. 10-188374 and 10-505188, irradiate ultraviolet rays at the time of pressurization, There is a technique in which an ultraviolet curable resin is cured and bonded.

[0003]

However, each of the above-mentioned methods for manufacturing an information recording medium has the following problems. In the hot-melt bonding method, the hot-melt is applied to the substrate that needs to be cooled, resulting in large deformation of the disk substrate. At times, the stress increases, and if the sheet is flattened by forcible pressing, distortion occurs inside the information recording medium, and there is a problem that the surface deflection acceleration of the mechanical characteristics increases. In the bonding method using a slow-curing ultraviolet-curing resin, it takes time for the adhesive to harden even if it is pressed and bonded flat, so it is difficult to maintain the flatness during pressing. There is a problem that the quality of the previous substrate shape affects the quality of the mechanical characteristics. The bonding method using a double-sided tape has a problem in that since bubbles enter between the tape and the disk substrate during bonding, vacuum suction is required for defoaming, resulting in poor productivity. In the above-described laminating method using an ultraviolet curable resin or an electron beam curable resin, since there is no pressing means, there is a problem that the flatness of the laminated information recording medium largely depends on the shape of the disk substrate.

As means for solving the above-mentioned problems, Japanese Patent Application Nos. 10-188374 and 10-505188 describe a bonding technique of irradiating ultraviolet rays at the time of pressurization to cure an ultraviolet-curable resin. ing. However, in this technique, since there is no means for alleviating the stress on the substrate caused by the pressure, the ultraviolet curing resin is cured and bonded in a state where the stress is accumulated on the substrate, and the distortion inside the substrate is caused. Therefore, there is a problem that birefringence increases.

Further, in the method described in Japanese Patent Application No. 4-19821, in which the adhesive is adhered while keeping the viscosity of the adhesive constant by a heating means at the time of pressurization, the entire press section is heated by a heater. It takes time to adjust the temperature,
Low mass productivity, easy failure such as disconnection of heater due to load of pressurization and decompression, heats the adhesive through the substrate, so the substrate is susceptible to thermal deformation and has poor thermal efficiency. When the substrate is used, since the melting point of polycarbonate is about 120 ° C., only an adhesive having a melting point of 120 ° C. or less can be used, and the high-temperature heat resistance is poor, and there is a possibility of being used at a high temperature. Have a problem that they cannot be used.

The present invention solves the above-mentioned disadvantages of the prior art, and is flatter, has better mechanical properties, and has less birefringence.
An object of the present invention is to provide a method and an apparatus for manufacturing an information recording medium capable of supporting high-density optical recording.

[0007]

According to the present invention, in order to achieve the above object, two disk substrates having an information recording layer on at least one of the two substrates are opposed to each other with the information recording layer inside, Between these disk substrates, a photo-curable adhesive that is cured by irradiation with light including a specific wavelength band is interposed, and the photo-curable adhesive is interposed when the information recording medium is manufactured by bonding under pressure. The two disk substrates are pressed flat, and at least one of the pressed disk substrates is irradiated with first light capable of heating the disk substrate without curing the photocurable adhesive. The present invention provides a method for manufacturing an information recording medium in which, after heating and after the disk substrate reaches a predetermined temperature, a second light for curing the photocurable adhesive is irradiated to cure the photocurable adhesive. .

According to the present invention, the two disk substrates are pressed flat via the uncured light-curable adhesive, and the first disk is irradiated with the first light in the flat state to thereby adjust the temperature of the disk substrates. Is heated to a predetermined temperature. Since the first light does not cure the photocurable adhesive, the stress inside the disk substrate caused by the pressure is removed by the annealing effect. Next, while maintaining the flatness of the disk substrate, the second light is irradiated to cure the photocurable adhesive, so that the recording medium is flatter, has better mechanical properties, has less birefringence, and is used for high-density optical recording. A suitable information recording medium can be manufactured. Further, according to the present invention, since the heating and cooling of the disk substrate can be performed instantaneously by irradiation / non-irradiation of the first light,
It is possible to provide a method for manufacturing an information recording medium which is more excellent in mass productivity than a conventional technique in which a hot melt is used or a whole heater is heated by a heater.

In the above, when a photo-curable adhesive is interposed between two disk substrates and bonded together, the photo-curable adhesive is applied between the disk substrates by a screen printing method or the like and then bonded. The application and the bonding may be performed separately, or the coating and the bonding may be performed simultaneously by a spin coating method or the like.

In the above-mentioned manufacturing method, two disk substrates having a photo-curable adhesive interposed therebetween are horizontally arranged and pressurized, and the first light and the second light are transmitted at least immediately below the disk substrate. It is preferable to irradiate from. As a result, pressurization with less stress caused by optical heating and curing of the bonding adhesive can proceed almost simultaneously, and bonding can be performed at high speed while maintaining the flatness of the disk substrate. . In order to realize light irradiation from directly below the disk substrate, at the time of pressing, the disk substrate is placed on a horizontal and light-transmitting pedestal, and the first light and the second light are combined with the pressure through this pedestal. Is preferably irradiated. Further, the first light and the second light can be irradiated not only from directly below but also from above.

According to a third aspect of the present invention, in the third aspect, two disk substrates having an information recording layer on at least one of them are opposed to each other with the information recording layer inside, and a specific wavelength band is included between these disk substrates. An apparatus for manufacturing an information recording medium by bonding a light-curing adhesive that is cured by light irradiation and bonding under pressure, wherein two disk substrates with the light-curing adhesive interposed are flatly applied. Pressing means for pressing, and first light irradiating means for irradiating at least one of the pressed disk substrates with first light capable of heating the disk substrate without curing the photocurable adhesive,
A second light irradiating means for irradiating a second light for curing the photo-curable adhesive is provided.

The pressurizing means, the first light irradiating means, and the second
The method for manufacturing an information recording medium according to the first aspect can be performed by using an apparatus for manufacturing an information recording medium having light irradiation means. In the above-described manufacturing apparatus, the first light irradiating unit or the second light irradiating unit is configured to input the first light or the second light from a direction perpendicular to an axial direction of the pressing unit, respectively. It is preferable that light is reflected on a mirror surface to irradiate the disk substrate. As a result, the disk substrate can be irradiated not only from the lower surface but also from the upper surface without obstructing the function of the pressurizing means, and uniform and efficient heating and curing can be performed. It is preferable that the mirror surface has fine unevenness and irregularly reflects the incident light. As a result, the entire disk substrate can be more uniformly irradiated.

It is preferable that the photo-curable adhesive is made of a resin having a good light absorbency, or a resin containing a powder of carbon or metal and having an improved light absorbency. In this case, the light irradiation also heats the thin film of the photocurable adhesive, thereby preventing the occurrence of distortion due to the temperature gradient at the interface between the disk substrate and the photocurable adhesive, and preventing the disk substrate from overheating by a predetermined amount. Can be heated to temperature. In general, the thickness of the thermosetting adhesive is as thin as about 10 microns, so that after the thermosetting adhesive is cured, light irradiation can be stopped and rapid cooling can be performed, thereby improving mass productivity and improving disk flatness. Can be secured.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a main cross-sectional view of an information recording medium manufacturing apparatus (hereinafter, referred to as “first apparatus”) according to a first embodiment of the present invention. In the first device, two disk substrates 3a and 3b each having an information recording layer (not shown) are opposed to each other with the information recording layer inside, and ultraviolet curing is performed between the disk substrates 3a and 3b. A device for manufacturing the information recording medium 3 by bonding under pressure and interposing a curable adhesive 3c, comprising a horizontal worktable 6 and the ultraviolet curable adhesive 3c placed on the worktable 6 Disk substrates 3a, 3
It has a pressurizing means 30 for pressurizing b flatly, and a light irradiating mechanism 7 incorporated in the work table.

The light irradiating mechanism 7 includes a disk substrate 3
a first light irradiating means 10 comprising a halogen lamp light source for heating a and 3b; a second light irradiating means 9 comprising a high pressure mercury lamp or a metal halide lamp for generating ultraviolet rays for curing the adhesive; And a condensing reflection mirror 8 for uniformly irradiating the light onto the disk substrates 3a and 3b. Also, the disk substrate 3
On the upper surface of the worktable 6 on which the a and 3b are mounted, a light-transmissive base 5 having a centering center shaft 4 for centering a disk substrate is fitted. As a material of the base 5, a transparent organic material such as an acrylic resin or a polycarbonate resin or a transparent inorganic material such as a quartz glass is preferable, and particularly preferably, a quartz glass having excellent strength and flatness is bonded to acrylic. It is a composite glass.

The pressurizing means 30 includes a pressurizing cylinder 1
When the cylinder 1 pushes down the pressing portion 2, a uniform pressure is transmitted to the two disk substrates 3 a and 3 b sandwiched between the base 5 and the pressing portion 2. The disk substrate is pressed flat.

In manufacturing an information recording medium using the first apparatus, first, two disk substrates 3a, 3b
With the information recording layer (not shown) inside, and the ultraviolet curable adhesive 3 is applied to the facing surface by a spin coater method or the like.
The centering member 4c is interposed, the centering is performed by the centering center shaft 4, and the centering member is mounted on the base 5. Next, the pressing means 30 is operated to apply uniform pressure to the disk substrates 3a and 3b by the pressing unit 2, and the first light irradiating means 10 for heating the disk substrate is used.
Is turned on, and the disk substrates 3a and 3b are heated by irradiating the disk substrates 3a and 3b with the first light from below, thereby removing the stress generated on the disk substrates by pressurization. At this time, the UV-curable adhesive 3c is also heated, thereby preventing distortion due to a temperature gradient at the interface between the disk substrate and the photocurable adhesive, and heating the disk substrate to a predetermined temperature while avoiding overheating. .

Next, the second light irradiating means 9 is turned on, and the second light (ultraviolet light) for curing the adhesive is irradiated from below to cure the ultraviolet-curable adhesive 3c. As a result, the disc substrates 3a and 3b are adhered in a state where stress (internal stress) is small while maintaining flatness, and the information recording medium 3 is manufactured. Irradiation and non-irradiation of ultraviolet rays are performed by opening and closing a shutter (not shown).

In the above, the combination of the bonding adhesive and the irradiation light source is not limited to the ultraviolet curable adhesive and the ultraviolet light source such as a high pressure mercury lamp or a metal halogen lamp. Other combinations of the photocurable adhesive for bonding and the irradiation light source include a combination of a visible light curable resin (for example, VL series manufactured by commercially available Three Bond Co.) and a simple irradiation system such as a halogen lamp, Thermosetting adhesive with improved light absorption by mixing carbon or metal powder with acrylate-based electron beam curing resin and electron beam irradiation system, or epoxy resin adhesive (modified nitrile epoxy resin, modified epoxy resin, etc.) And a simple irradiation system composed of a combination of a halogen lamp and the like. As a combination of an adhesive having both thermosetting and photocuring properties and an irradiation light source, a thermosetting ultraviolet curable resin (for example, 301 manufactured by Three Bond Co., Ltd.)
3C) and an ultraviolet light source without a cold mirror such as a high-pressure mercury lamp or a metal halogen lamp may be used.

(Second Embodiment) Another embodiment of the present invention will be described below with reference to FIG. FIG. 2 is a main cross-sectional view of an information recording medium manufacturing apparatus (hereinafter, referred to as “second apparatus”) according to a second embodiment of the present invention. The second device further includes a disk substrate 3a,
3b, an upper first light irradiating means 11 composed of a halogen lamp light source, and a light irradiating from the upper first light irradiating means 11 attached to the lower surface of the pressing portion 2 of the pressing means. A reflection pressing mechanism 13 in which a reflection mirror 12 for reflecting and irradiating the disk substrates 3a and 3b is applied is added. This reflection mirror 12
Is provided with irregular reflection projections having fine irregularities on the surface thereof, so that the entire disk substrate can be irradiated with uniform light.

This second device comprises a lower first light irradiating means 1
With the first light from 0 and the first light from the combination of the upper first light irradiating means 11 and the reflection pressing mechanism 13 on the upper side, the disk substrates 3a and 3b are uniformly heated from above and below. Therefore, the stress caused by the pressure generated in the manufactured information recording medium 3 can be reduced more quickly,
The information recording medium 3 that is flat and has low birefringence can be efficiently manufactured.

(Third Embodiment) Hereinafter, still another embodiment of the present invention will be described with reference to FIG. FIG. 3 is a main cross-sectional view of an information recording medium manufacturing apparatus (hereinafter, referred to as “third apparatus”) according to a third embodiment of the present invention. The third device converts the first light and the second light into pressure means 3
It has an upper light source 15 and a lower light source 18 that are incident from a direction perpendicular to the 0 axis direction. These light sources 1
5, 18 irradiate light containing a visible light component such as a halogen lamp. An upper reflection pressing mechanism 17 is mounted on the lower surface of the pressing portion 2 of the pressing means 30 composed of the cylinder 1 and the pressing portion 2, and a lower reflecting mechanism 20 is mounted on the upper surface of the worktable 21. Between the upper reflection pressing mechanism 17 and the lower reflection mechanism 20, two disk substrates 14a and 14b with a visible light curable adhesive (VL series manufactured by Three Bond) 14c interposed are arranged. It has become.

The upper reflection pressing mechanism 17 and the lower reflection mechanism 20 reflect the light emitted from the upper light source 15 or the lower light source 18, respectively, to reflect the disk substrates 14a and 14a.
It has reflection mirrors 16 and 19 for irradiating toward 14b. Each of these reflection mirrors 16 and 19 is provided with irregular reflection projections having fine irregularities on the surface so that the entire disk substrate can be irradiated with uniform light.

This third device presses the disk substrates 14a and 14b by the pressing mechanism 30 while the upper light source 15
And the lower light source 18 emits visible light from above and below, so that the disk substrates 14a and 14b and the visible light curable adhesive 14c are uniformly heated, so that the stress due to pressure is alleviated more quickly. At the same time, the visible light curable adhesive 14c is subsequently cured, and the information recording medium 14 having a flat and low birefringence can be efficiently manufactured by one light irradiation.

[0025]

As described above, according to the method for manufacturing an information recording medium of the present invention, two disk substrates having a photocurable adhesive interposed therebetween are flatly pressed, and the disk substrates are pressed with the photocurable adhesive. Is irradiated with a first light capable of heating the disk substrate without curing, and then heated, and then irradiated with a second light for curing the photocurable adhesive to cure the photocurable adhesive. Therefore, the stress in the disk substrate can be alleviated by pressurization and the bonding adhesive can be cured in the same device, and the stress can be alleviated to prevent generation of fine undulations and wrinkles. At the same time, it is possible to bond the disk substrates while maintaining the flatness of the disk substrates, and it is possible to efficiently manufacture an information recording medium having less birefringence and excellent mechanical properties. Further, an apparatus is used in which the first light or the second light is incident from a direction perpendicular to the axial direction of the pressing means, and the incident light is reflected by a mirror surface to irradiate the disk substrate. In this case, light can be simultaneously irradiated from the top and bottom, and a light wavelength band that efficiently heats the disk substrate and a light wavelength band that efficiently cures the photocurable adhesive can be selected. Irradiation and stop enable rapid heating and cooling, thereby further improving productivity.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a second embodiment of the present invention.

FIG. 3 is a schematic sectional view showing a third embodiment of the present invention.

[Explanation of symbols]

1: Cylinder 2: Pressing part 3: Information recording medium 3a, 3b; Disk substrate 3c; UV curable adhesive 4: Centering center shaft 5: Base 6: Work table 7: Light irradiation mechanism 8: Reflecting mirror 9: Second light irradiation means 10: First light irradiation means 11: Upper first light irradiation means 12: Reflection mirror 13: Reflection pressure mechanism 14: Information recording medium 14a, 14b; Disk substrate 14c; Visible light curable adhesive 15 : Upper light source 16: reflective mirror 17: upper reflective pressing mechanism 18: lower light source 19: reflective mirror 20: lower reflective mechanism 21: work table 30: pressing means

Claims (5)

[Claims] 1. An image pickup apparatus comprising an information recording layer on at least one side.
The two disk substrates face each other with the information recording layer inside, and a light-curable adhesive that is cured by irradiation with light including a specific wavelength band is interposed between these disk substrates, and is bonded under pressure. In manufacturing an information recording medium, two disk substrates with the photocurable adhesive interposed therebetween are pressed flat, and the photocurable adhesive is not cured on at least one of the pressurized disk substrates. Irradiating a first light capable of heating the disk substrate and heating the disk substrate, and after irradiating a second light for curing the photocurable adhesive after the disk substrate reaches a predetermined temperature, the light is irradiated. A method for producing an information recording medium, comprising curing a curable adhesive. 2. A method in which two disk substrates with the photo-curable adhesive interposed therebetween are arranged horizontally and pressurized, and the first light and the second light are irradiated from at least immediately below the disk substrate. The method for manufacturing an information recording medium according to claim 1, wherein: 3. An image recording apparatus comprising: an at least one information recording layer;
The two disk substrates face each other with the information recording layer inside, and a light-curable adhesive that is cured by irradiation with light including a specific wavelength band is interposed between these disk substrates, and is bonded under pressure. An apparatus for manufacturing an information recording medium, comprising: pressing means for flatly pressing two disk substrates with the photocurable adhesive interposed therebetween; First light irradiating means for irradiating first light capable of heating the disk substrate without curing the curable adhesive, and second light irradiating means for irradiating second light for curing the photocurable adhesive An information recording medium manufacturing apparatus, comprising: 4. The first light irradiating means and the second light irradiating means respectively enter the first light or the second light from a direction perpendicular to an axial direction of the pressing means, and enter the first light or the second light. 4. The apparatus for manufacturing an information recording medium according to claim 3, wherein the disk substrate is irradiated with light reflected by a mirror surface. 5. The mirror according to claim 4, wherein the mirror surface has minute irregularities and irregularly reflects the incident light.
Manufacturing apparatus for the information recording medium described in the above.