JPH0432045A - Optical disk sticking method - Google Patents

Abstract

PURPOSE:To improve the mechanical characteristic by convexing at least one sticking face and bringing this face into contact with the other successively from the center part to the outer peripheral side to stick them to each other. CONSTITUTION:The sticking face of at least one disk 8a is protruded to the other disk 8b and is brought into contact with the other disk 8b successively from the center part to the outer peripheral side to stick them to each other. For the purpose of sticking them in this manner, a disk holding body 6a whose one disk suction face is convex and has 2X10<2>cm curvature radius is used to hold the disk 8a with the face opposite to the face coated with a hot melt type adhesive 5a by vacuum suction, and respective disk centers are aligned. Respective disk holding bodies are gradually approximated to each other, and vacuum suction is successively released from the disk inner peripheral side to the outer peripheral side when adhesion faces of two disks come into contact with each other, and thereby, two disks are stuck to each other by disk's own rigidity. Thus, penetration of air bubbles is prevented to improve the mechanical characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a bonding method for producing a set of optical disks by bonding two substrates together using an adhesive.

[Conventional technology]

Conventionally known methods for producing optical discs include forming a recording film on a plastic substrate made of polycarbonate resin, polymethyl methacrylate resin, epoxy resin, etc. by vacuum evaporation or sputtering, and then depositing a protective film on top of the recording film. A film is formed to produce a disc as shown in Fig. 1, and then a hot-melt adhesive or the like is applied to the recording film forming side of the two discs, and then as shown in Fig. 5. One disk is brought into contact with the other vacuum-adsorbed disk while the surface opposite to the adhesive surface is held by vacuum suction so that the centers of the respective disks coincide. Thereafter, the vacuum suction was released and the two disks brought into contact were pressed together using a pressure plate of 100 kg.

However, with this method, no matter how good the flatness and parallelism of each disk holder are, the thickness distribution of the substrate itself is not uniform, so spaces are created within the bonding surface during bonding, and air bubbles are mixed in. However, the mechanical properties such as the warp angle and the instantaneous acceleration of surface runout, which are important properties of an optical disk, deteriorate, resulting in a decrease in quality.

[Problem to be solved by the invention]

An object of the present invention is to provide a method for laminating optical disks that prevents the inclusion of air bubbles during lamination of optical disks, improves mechanical properties, and prevents deterioration in quality.

[Means to solve the problem]

The present invention was completed in order to solve the above-mentioned problems, and the present invention is made by making at least one of the two disks have a convex bonding surface with respect to the other disk and making contact from the center of the disk. It is characterized by laminating the discs by sequentially contacting them up to the outer circumferential side of the discs.

[Example 1] As shown in Fig. 1, a φ130 mm piece with a guide groove 2 formed on one side by injection molding polycarbonate.
A recording film 3 was formed by sputtering on the guide groove forming surface side of a disc-shaped substrate 1, and a protective film 4 was formed on the recording film to produce two discs. Place these discs with the recording film forming side facing up and place them in a roll coater RT-4 manufactured by Matsushita Industries.
ACI hot melt adhesive PS-450 by 00
was applied to the recording film formation side.

Next, as shown in FIG. 2, one of the disks 8a is attached to the surface coated with the hot melt adhesive 5a using a disk holder 6a whose disk suction surface has a convex shape and a radius of curvature of 2×10 cm. The other disk 8b is held by vacuum suction, and the surface opposite to the surface coated with the hot melt adhesive 5b is held such that the disk suction surface has a flat shape. It was held by vacuum suction by the body 7b. The vacuum suction part of these disk holders has a φ2mm hole with a radius of 1 from the center of the holder.
5.30.45.5Q, it has a structure in which eight holes are made on the circumference at 63 mm positions. Further, a diaphragm type pump manufactured by ULVAC Vacuum Mechanism Co., Ltd. is used for vacuum suction.

After the disks were vacuum-adsorbed, the positions of each disk holder were adjusted so that the center of each disk was aligned, and then each disk holder was moved gradually closer until the adhesive surfaces of the two disks came into contact. By the way, I stopped moving. In this state, the distance between the outermost peripheries of the two disks is approximately 1 mm. Next, when the vacuum suction of each disk holder is sequentially released from the inner circumferential side to the outer circumferential side of the disk at intervals of about 0.4 seconds, the two disks are bonded together due to the rigidity of the disk itself.

The two discs bonded together in this way were pressed with a pressure of 100 kg using a pressure plate to produce an optical disc.

Among the mechanical properties of this optical disk, the warpage angle physical properties are shown in FIG. 3, and the surface runout instantaneous acceleration characteristics are shown in FIG.

[Example 2] As shown in Fig. 1, a φ130 mm piece with a guide groove 2 formed on one side by injection molding polycarbonate.
A recording film 3 was formed by sputtering on the guide groove forming surface side of a disc-shaped substrate 1, and a protective film 4 was formed on the recording film to produce two discs. Place these discs with the recording film forming side facing up and place them in a roll coater RT-4 manufactured by Matsushita Industries.
ACI hot melt adhesive PS-450 by 00
was applied to the recording film formation side.

Next, as shown in FIG. 5, one of the disks 8a is attached to the surface coated with the hot melt adhesive 5a using a disk holder 6a whose disk suction surface has a convex shape and a radius of curvature of 2×10 cm. The other disk 8b is held by vacuum suction on the side opposite to the hot melt adhesive 5b, and the disk suction surface has a convex shape with a radius of curvature. The disk was held by vacuum suction using a disk holder 6b having a size of 2×10 2 cm. The vacuum suction part of these disc holders is φ2mm.
The holes have a radius of 15, 30, 45, respectively from the center of the holder.
It has a structure in which eight holes are formed on the circumference at a position of 50.63 mm. Further, a diaphragm type pump manufactured by ULVAC Vacuum Mechanism Co., Ltd. is used for vacuum suction.

After the disks were vacuum-adsorbed, the positions of each disk holder were adjusted so that the center of each disk was aligned, and then each disk holder was moved gradually closer until the adhesive surfaces of the two disks came into contact. By the way, I stopped moving. In this state, the distance between the outermost peripheries of the two disks is approximately 2 mm. Next, when the vacuum suction of each disk holder is sequentially released from the inner circumferential side to the outer circumferential side of the disk at intervals of about 0.4 seconds, the two disks are bonded together due to the rigidity of the disk itself.

The two discs bonded together in this way were pressed with a pressure of 100 kg using a pressure plate to produce an optical disc.

Among the mechanical properties of this optical disk, the warpage angle characteristic is shown in FIG. 3, and the surface runout instantaneous acceleration characteristic is shown in FIG.

[Example 3] A disk was prepared in the same manner as in Example 1, and the disk was vacuum-adsorbed as shown in FIG. Both discs were released at the same time, and the two discs were pasted together. The mechanical properties and surface runout instantaneous acceleration properties of this optical disk were slightly worse than those of Example 1, but better than those of the conventional method.

[Comparative example]

As shown in Figure 1, a φ130mr piece with a guide groove 2 formed on one side by injection molding polycarbonate.
A recording film 3 was formed by sputtering on the guide groove forming surface side of a disc-shaped substrate 1 of n, and a protective film 4 was formed on this recording film to produce two discs. Place these discs with the recording film forming side facing up and place them in a roll coater RT- manufactured by Matsushita Industries.
400 by ACI hot melt adhesive PS-45
0 was applied to the side on which the recording film was formed.

Next, as shown in FIG. 6, one of the disks 8a is vacuum-adsorbed on the surface opposite to the surface coated with the hot-melt adhesive 5a using a disk holder 7a having a flat disk suction surface. The other disk 8b was held by vacuum suction on the surface opposite to the surface coated with the hot melt adhesive 5b by a disk holder 7b whose disk suction surface had a flat shape. The vacuum suction portion of these disk holders has a structure in which eight holes each having a diameter of 2 mm are formed on the circumference at positions with a radius of 15, 30, 45, and 50.63 mm from the center of the holder. Further, a diaphragm type pump manufactured by ULVAC Vacuum Mechanism Co., Ltd. is used for vacuum suction.

After the disks were vacuum-adsorbed, the positions of each disk holder were adjusted so that the center of each disk was aligned, and then each disk holder was moved gradually closer until the adhesive surfaces of the two disks came into contact. By the way, I stopped moving. In this state, the vacuum suction of each disc holder was released and the two discs were bonded together.

The two discs bonded together in this way were pressed with a pressure of 100 kg using a pressure plate to produce an optical disc.

Among the mechanical properties of this optical disk, the warpage angle characteristic is shown in FIG. 3, and the surface runout instantaneous acceleration characteristic is shown in FIG.

〔Effect of the invention〕

As described above, in the method for laminating optical disks according to the present invention, at least one disk is brought into contact with the other disk with its laminating surface convex from the center of the disk, and the disks are successively brought into contact with each other up to the outer periphery of the disk. Therefore, inclusion of air bubbles can be prevented and mechanical properties can be improved. Therefore, productivity can be improved without deterioration of quality. FIG. 1 is a side view of a disk, and FIG. 2 is an embodiment 1 of an optical disk laminating apparatus according to the optical disk laminating method of the present invention. FIG. 3 is a side view of the disc holder of FIG. Figure 5 shows a comparison between the instantaneous surface runout acceleration characteristics of an optical disk produced by the conventional method and the instantaneous surface runout acceleration characteristics of an optical disk produced by the conventional method. FIG. 6 is a side view of the disk holder of Example 2, and FIG. 6 is a side view of the disk holder of an optical disk bonding apparatus according to a conventional optical disk bonding method shown as a comparative example.

1: membrane, 5 s6 7 b = 8b: Sufu.

Claims (2)

[Claims] (1) At least one of two disc-shaped substrates has an information recording film, and in a method of bonding two discs with an adhesive with the recording film inside, at least one disc is attached to the other disc. On the other hand, a method for laminating optical disks is characterized in that the laminating surface is made convex and the disks are brought into contact with each other from the center, and then the disks are sequentially brought into contact with each other until the outer circumference of the disk is brought into contact. (2) At least one disk is attached to the other disk, and the bonding surface is 2 x 10^2 cm to 2 x 10^3 cm.
2. The method for laminating optical disks according to claim 1, wherein the optical disks are laminated by making the disks convex with a radius of curvature in the range of m and contacting from the center of the disks and sequentially contacting the outer circumferential side of the disks.