JPH06119660A - Production of information recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical disk with high production efficiency at a low production cost. CONSTITUTION:An adhesive 20 is stuck to a 1st substrate 10 in <=1Torr vacuum under 2-10kgf/cm<2> pressure in a 1st process. The 1st substrate 10 with the stuck adhesive 20 is stuck to a 2nd substrate 110 under the same conditions in a 2nd process. The objective disk free from bubbles between the adhesive 20 and each of the 1st and 2nd substrates 10, 110 is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a plate-shaped medium, and more particularly to a method for adhering an information recording medium used for optical information recording.

[0002]

2. Description of the Related Art An information recording medium used for optical information recording, that is, an optical disk is generally formed by laminating two disks each having a recording film or a reflective film formed on at least one surface of a support. Optical discs formed by this bonding are classified into two types depending on the disc structure.

The first class is the air sandwich structure. In this structure, spacers are arranged on the inner and outer peripheries of the discs, and the recording layer portions formed on the respective discs are maintained at a desired distance through the spacers. To be done. The second category is
There is a full-scale adhesive structure. In this structure, the adhesive is provided on the entire surfaces of the two discs, and the two discs are completely adhered. These two structures (that is, manufacturing methods) are used properly depending on, for example, the recording method or the size of the disc. Of these, the full-surface adhesive structure is used, for example, in a read-only optical video disk or a magneto-optical recording disk.

By the way, in the case of the whole-surface adhesive structure, when a kind of adhesive, for example, a solvent-type adhesive is used, hardening distortion of the disk substrate or a recording film formed on the recording surface or the reflecting surface is used. It is known that erosion of the reflective film and the like occur. From this, as a method of attaching a disk in which hardening distortion of the disk substrate and erosion of the recording film and the reflective film are unlikely to occur, for example, Japanese Patent Publication No. 63-6725.
No. 8 proposes a laminating method using a hot melt adhesive. On the other hand, even when the above hot melt adhesive is used, undesired heat is mainly applied to the disk substrate mainly made of a resin material, and thus there is a concern that the substrate may be deformed. Therefore, as a laminating method that does not use heat, for example, Japanese Patent Application Laid-Open No. 1-276447 proposes a laminating method using a double-sided adhesive.

[0005]

However, even when the above double-sided pressure-sensitive adhesive is used, wrinkles or bubbles are generated when the pressure-sensitive adhesive is applied, which may cause defects. There was a problem that it would end up. This invention
It is an object of the present invention to provide an optical disc having high production efficiency and low manufacturing cost.

[0006]

The present invention has been made on the basis of the above-mentioned problems, and two plate-shaped recording media having a recording film or a reflective film formed on at least one surface thereof are bonded together. A method of manufacturing an information recording medium, comprising forming an adhesive layer on at least one of two recording mediums facing each other with a distance therebetween,
[Toggle] 2 [Kgf / cm ² ] Above 10 [Kgf /
cm ² The present invention provides a method for manufacturing an information recording medium that applies the following pressure.

[0007]

According to the present invention, when a double-sided pressure-sensitive adhesive is used to manufacture an information recording medium having a full-face adhesive structure, the double-sided pressure-sensitive adhesive and the first support and the first double-sided pressure-sensitive adhesive already bonded to each other are used. The support and the second support are in a vacuum of 1 [Torr] or less,
2 [Kgf / cm ² ] Above 10 [Kgf / cm ² ] Laminated by the following pressure. According to this laminating method, it is possible to prevent air bubbles from being generated between the double-sided pressure-sensitive adhesive and the first and second supports, and to prevent wrinkles on the pressure-sensitive adhesive.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows, for example, a schematic cross section of an optical information recording medium, that is, an optical disc (information recording medium) 100 manufactured according to the embodiment of the present invention.

The optical disc 100 is in close contact with the first support (plate-shaped recording medium) 10 and the second support (plate-shaped recording medium) 110, which are substantially disc-shaped, facing each other. Has been done. The first and second supports 10 and 110 are formed of a transparent material, for example, a resin such as acrylic or polycarbonate.

The inner surfaces of the first and second supports 10 and 110 are, for example, a metal film, which is a recording film or laser whose state is changed by irradiation with laser light or the like. The reflective films 12 and 112 that reflect the light are formed in thin layers by a method such as vapor deposition. A double-sided adhesive 20 having substantially the same inner and outer diameters as those of the first and second supports 10 and 110 is adhered between the recording film or the reflective film 12 and 112. As the pressure-sensitive adhesive 20, a pressure-sensitive double-sided pressure-sensitive adhesive having good environment resistance and adhesive strength and capable of being bonded without applying heat is used. An acrylic adhesive or a silicone adhesive is preferably used as the adhesive 20. The double-sided adhesive 20 is shown in FIG.
As shown in, the first and second separators are usually
Protected via switches 22 and 122.

According to FIG. 1, an optical disc 100 has an exhaust valve 4, at least a first and a second support 10, and
One of 110 or the disc mount 2b on which the adhesive 20 is placed, and the adhesive 20 or the remaining support 1
Disc mount 2 with holding 10 (or 10)
It is pressure-bonded by a sticking device 2 which is composed of a disk pressure plate 2a which is pressed toward b. As is apparent from FIG. 1, the optical disc 100 is formed by at least the first support 10 and the adhesive 20 by the first step shown in FIG.
After being bonded, the remaining support 110 and the first support 10 to which the adhesive 20 has already been applied are applied by the second step shown in FIG. 1 (b).

More specifically, as is apparent from FIG. 1A, the adhesive 20 from which the first separator 22 has been removed is placed on the disk mount 2b at the substantially central portion thereof. in this case,
The surface on which the separator remains is opposed to the disc mount 2b. The adhesive 20 on the disc mount 2b
Alternatively, at the center of the surface on which the support 10 is placed, there is arranged a spindle (not shown) which is formed so as to be inserted into a central hole located at the center of the adhesive 20 (or the support 10). . Therefore, the adhesive 20 is used for the disc mount 2b.
It is located exactly in the center of. On the other hand, the disk pressing plate 2a is provided with a storage film or a reflective film 12 on the disk mount 2
The first support body 10 facing the b side is adsorbed (placed)
To be done. In this case, the first support 10 is fixed to a desired position on the disk pressing plate 2a via a plurality of clamp devices (not shown) arranged on the disk pressing plate 2a, such as a claw. A positioning hole (not shown) into which a spindle (not shown) protruding from the disc mount 2b is inserted is formed in the center of the surface of the disc pressing plate 2a where the supports 10 and 110 are attracted. Therefore, the support body 10 is accurately positioned substantially at the center of the disk pressure plate 2a, and is also accurately positioned with respect to the adhesive 20 already mounted on the disk mount 2b.

With the first support 10 adsorbed on the disc pressure plate 2a and the adhesive 20 placed on the disc mount 2b, a pasting device is attached via a vacuum pump or the like (not shown) connected to the valve 4. The pressure in 2 is reduced (air is removed as indicated by arrow B). When the atmospheric pressure in the sticking device 2 reaches an optimum atmospheric pressure described later, both the disc pressure plate 2a and the disc mount 2b or the disc pressure plate 2a are moved by a hydraulic device (not shown), etc. An optimum pressure P, which will be described later, is provided between the pressure sensitive adhesive 20 and the support 10 to bond the adhesive 20 and the first support 10.

Subsequently, as shown in FIG. 1B, the adhesive 20 is adhered through the first step shown in FIG. 1A, and the second adhesive 20 is attached. The first support 10 with the separator 122 of FIG.
It is placed almost in the center. On the other hand, the disc pressure plate 2a
A memory film or a reflective film 112 is attached to the disk mount 2b.
The second support 110 directed to the side is the disk pressure plate 2a.
Is adhered to the desired position. Hereinafter, similar to the first step shown in FIG. 1A, a desired size is obtained between the first support 10 and the second support 110 to which the adhesive 20 is already adhered. An optical disc 100 is formed by applying a pressure P having a pressure of

FIGS. 4 to 6 show the first support 10 and the adhesive 20 or the first support on which the adhesive 20 is already adhered.
Important when 10 and the second support 110 are bonded,
Atmospheric pressure inside the pasting device 2 and mechanical characteristics of the optical disc 100
The relationship between (the amount of surface deviation), the pressure provided between the disk pressure plate 2a and the disk mount 2b, and the mechanical characteristics of the optical disk 100 (the amount of surface deviation and the roundness of the groove) is shown. .

According to FIG. 4, the mechanical characteristics of the optical disk, that is, the amount of surface deviation with respect to the atmospheric pressure in the sticking device 2, is as follows:
It is rapidly increased for atmospheric pressures above about 20 [Torr].
The amount of surface deviation is such that the adhesive 20 is adhered between the first support 10 and the adhesive 20 or between the first support 10 and the second support 110 to which the adhesive 20 is already adhered. It is caused by the increase of air bubbles or wrinkles that may occur during the operation.

From this, the atmospheric pressure in the sticking device 2 is
Preferably, it is specified to be 10 [Torr] or less. However, even with an optical disc formed under a pressure of 10 [Torr], the amount of surface blur is rapidly increased at the end of the environmental test at 60 ° C. × 85% RH × 2000H.
(See Figure 4, dotted line). This indicates that the optical disc 100 formed under an atmospheric pressure of 10 [Torr] cannot maintain sufficient characteristics against environmental changes or changes with time. On the other hand, at 1 [Torr] or less, the above-mentioned amount of surface blur is stable at a level almost the same as the initial stage of bonding. From this, the air pressure in the sticking device 2 is more preferably specified to be 1 [Torr] or less. The disc pressing plate 2a and the disc mount 2b in the pasting device 2 are configured to be highly airtight and to provide a vacuum degree of at least 1 [Torr] or less, more preferably 0.1 [Torr] or less.

According to FIGS. 5 and 6, the disk pressure plate 2
The pressure provided between a and the disc mount 2b, the amount of surface deviation of the optical disc 100, and the distortion rate of the roundness of the groove are such that the atmospheric pressure in the sticking device 2 is 1 [Torr] or less. Is generally good under a relatively wide range of pressures.

However, the above pressure is 2 [Kgf / cm ² ]
In the following cases, air bubbles (or, although not apparently air bubbles, adhesive non-uniformity that becomes air bubbles through an environmental test) may occur in the adhesive 20 although it is slight. As is clear from FIG. 5, in this range, there is a problem that the amount of surface run-up is sharply increased at the end of the environmental test similar to that of FIG.
(Indicated by the dotted line).

As is apparent from FIG. 6, when the pressure is increased, for example, 12 [Kgf / cm ² When the back and forth pressure is applied, the roundness of the groove formed on the optical disk deteriorates (the groove deforms) although the surface runout amount shown in FIG. 5 is not increased. It has been confirmed. The deterioration of the roundness of the group is caused by the pressure of 10
[Kgf / cm ² ] In the following cases, it is generally good. In addition, the roundness of the group shown in FIG. 6 does not change even after the environmental test (see the dotted line). On the other hand, the pressure is 10 [Kgf / cm ² If it is larger than the above value, cracks may occur on the recording film 12 (or 112) or the reflection film 112 (or 12) in addition to the deterioration of the circularity of the groove. Therefore, the pressure provided between the disc pressure plate 2a and the disc mount 2b is preferably 2 [Kgf / cm ² ] Above 10 [Kgf / cm ² ] Defined below.

Here, the surface runout and the groove roundness are taken up as typical examples, but other mechanical characteristics, recording / reproducing characteristics and the like are also good if they are laminated under the above conditions. From this, when forming the whole-adhesion type optical disc 100 having the structure shown in FIG. 3, the pressure inside the attaching device 2 is set to 1 [Torr] or less, and the disc pressure plate 2a and the disc mount 2b are separated. The pressure provided between 2 [Kgf / cm ² ] Above 10 [Kgf / cm ² ] It is preferable to perform pressure bonding within the following range. When the optical disc manufacturing by pressure bonding is performed under atmospheric pressure, the adhesive 20 and the first support 10 or the first support 10 and the second support 110 are pasted together. Bubbles and wrinkles enter the mating surface,
As described above, it is not possible to obtain a satisfactory bonded state as a product. FIG. 7 shows a modified example of the optical disc shown in FIG.

According to FIG. 7, an optical disc 200 is a reinforcing plate in which adhesive layers (not shown) are formed on both sides in place of the adhesive 20 in the optical disc 100 shown in FIG.
The first support 10 and the second support 110 are pressure-bonded to each other via 30.

The optical disc 200 is shown in FIGS.
Similar to the optical disc 100 described above via (b),
First, the reinforcing plate 30 and the first support 10 are bonded by the first step shown in FIG. 1 (a), and the reinforcing plate 30 is already bonded by the second step shown in FIG. 1 (b). It is formed by adhering the support 10 and the second support 110. When the optical disc 200 is pasted, the pressure inside the pasting device 2 is 1 [Torr] or less, and the pressure provided between the disc pressing plate 2a and the disc mount 2b is 2 [Kgf / cm ² ] Above 10 [Kgf / cm ² ] It is as already explained that it is prescribed within the following ranges.

[0024]

As described above, according to the present invention,
When manufacturing an information recording medium having a double-sided adhesive structure using a double-sided adhesive, a double-sided adhesive and a first support, and a first support and a second support to which the double-sided adhesive has already been stuck Are bonded in a vacuum with an atmospheric pressure of approximately 1 [Torr] or less. An optical disc manufactured under this adhesion condition has, for example, reduced mechanical characteristics, that is, air bubbles, as compared with an optical disc manufactured under atmospheric pressure. In addition, the pressure applied to the optical disk is 2 [Kgf / cm ² ] Above 10 [Kgf
/ cm ² ] By the following provisions, the deformation of the optical disc is prevented and the production efficiency is improved. From this, it is possible to provide an optical disc that has little environmental change and good environmental resistance at a low production cost.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a sticking device that is an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an adhesive used in the application device shown in FIG.

FIG. 3 is a cross-sectional view of an optical disc manufactured through the pasting device shown in FIG.

FIG. 4 is a graph showing the relationship between the atmospheric pressure in the pasting device and the amount of surface deviation of the optical disc.

FIG. 5 is a graph showing the relationship between the pressure applied to the optical disc and the amount of surface deviation of the optical disc.

FIG. 6 is a graph showing the relationship between the pressure applied to the optical disc and the deformation of the optical disc (change in the circularity of the groove).

FIG. 7 is a schematic cross-sectional view of a modification of the optical disc shown in FIG.

[Explanation of symbols]

2 ... Sticking device, 2a ... Disk pressure plate, 2b ... Disk mount, 4 ... Valve, 10 ... First support, 12 ... Memory film or reflective film, 20 ... Adhesive, 22 ... First separator,
30 ... Reinforcing plate, 100 ... Optical disk, 110 ... Second support,
112 ... Memory film or reflective film, 122 ... Second separator,
P ... pressure.

Claims (1)

[Claims] 1. A method for manufacturing an information recording medium by laminating two plate-shaped recording media having a recording film or a reflective film formed on at least one surface thereof, which are opposed to each other at a distance. An adhesive layer is formed on at least one of the two plate-shaped recording media, each recording medium is housed in a vacuum having an atmospheric pressure of 1 [Torr] or less, and 2 layers are formed in a direction orthogonal to the adhesive layer. [Kgf / cm ² ] Above 1
0 [Kgf / cm ² ] A method for manufacturing an information recording medium which applies the following pressure.