JPH1092015A - Optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk in which ultraviolet curing resin, that is used to paste disk substrates together, does not swell out to the inside of the center holes of the substrates and the substrates are surely pasted together. SOLUTION: An optical disk 10 is provided with plural disk substrates 11 and 13 which have center holes 11a and 13a at their centers for clamping, recording layers 12 and 14 which are formed in the region between clamping zones 11b and 13b surrounding the center holes and the outer edges at the surface of each disk substrate and ultraviolet curing resin 15 which pastes the disks together. Note that the disk 10 is constituted to provide adhesive reservoirs 16 and 17 in the region between the center holes and the clamping zones at the parting surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk constituted by bonding a plurality of disk substrates for recording high-density information, for example.

[0002]

2. Description of the Related Art Conventionally, an optical disk for recording high-density information is constructed by bonding two disk substrates as shown in FIG. In FIG. 2, an optical disc 1 is formed by forming a surface of a disc-shaped first disc substrate 2 made of a transparent synthetic resin such as polycarbonate into a shape representing information, and then forming a reflective film of, for example, an aluminum thin film. As a result, a recording layer 3 is formed, and a second disk substrate 4 provided with a recording layer 5 like the first disk substrate 2 is further provided thereon via an ultraviolet curable resin 6 as an adhesive. The disk substrates 2 and 4 are attached by being mounted on the substrate and curing the ultraviolet-curable resin 6 by ultraviolet irradiation.

[0003] Each of the disk substrates 2 and 4 has, at the center thereof, clamping center holes 2a and 4a for fixing and holding the optical disk 1 during recording or reproduction of the optical disk 1, and the center holes 2a and 4a. So-called clamping zones 2b, 4 around the 2a, 4a
b. For example, when the optical disc 1 has a diameter of 120 mm, the center holes 2a and 4a have a diameter of 15 m.
m.

On the other hand, the recording layers 3 and 5 are formed on the surface of the disk
It is formed in a region between the outer peripheral edge of the disk substrate 2 and the outer peripheral edge of the disk substrate 2.

[0005]

By the way, in the optical disk 1 as described above, the ultraviolet curable resin 6 is
Since the viscosities are relatively low, it is difficult to control the thickness when laminating the disk substrates 2 and 4.

For this reason, if the amount of the UV-curable resin 6 applied is small, as shown in FIG.
A region A that does not spread over the entire surface between the disk substrates 2 and 4 and is not bonded by the ultraviolet curable resin 6 occurs. Therefore, there is a problem that the disk substrates 2 and 4 may be peeled off from each other with use.

When the amount of the UV-curable resin 6 applied is large, the UV-curable resin 6 protrudes inside the center holes 2a and 4a of the disk substrates 2 and 4, as indicated by reference numeral B in FIG. As a result, when recording or reproducing data on or from the optical disk 1, the optical disk 1 is not correctly clamped, and the recording / reproducing characteristics are degraded.

In view of the above, an object of the present invention is to provide an optical disk wherein an ultraviolet curable resin for bonding a disk substrate does not protrude into a center hole of the disk substrate, and the disk substrate is securely bonded. It is intended to provide.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided, in accordance with the present invention, a plurality of disk substrates having a center hole for clamping at a center thereof, and a plurality of disk substrates surrounding the center hole on a surface of each disk substrate. In the optical disk formed by laminating the recording layer and each disk substrate in the region between the clamping zone and the outer edge of the optical disk, each of the disk substrates has a center hole and a clamping zone on its bonding surface. This is achieved by an optical disk characterized in that an adhesive reservoir is provided in a region between them.

According to the above arrangement, when the two disk substrates are bonded with the ultraviolet-curable resin, the ultraviolet-curable resin may flow inward toward the center hole when the applied amount is large. In addition, the UV curable resin is prevented from flowing into the center hole by flowing into the concave groove.

Thus, if the application amount of the ultraviolet-curing resin is set to be large, even if the application amount varies, the ultraviolet-curing resin is absorbed into the concave grooves when the disk substrates are bonded. As a result, it does not protrude into the center hole of the disk substrate. Therefore, the disk substrates are securely bonded together, and the optical disk formed by the bonding is correctly clamped by the clamp member of the optical disk device, so that the recording or reproduction of the optical disk is performed correctly.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIG. The embodiment described below is a preferred specific example of the present invention, and thus various technically preferable limitations are added. However, the scope of the present invention particularly limits the present invention in the following description. The embodiment is not limited to these embodiments unless otherwise stated.

FIG. 1 shows an embodiment of an optical disk according to the present invention. In FIG. 1, an optical disk 10
For example, after the surface of a disk-shaped first disk substrate 11 made of a transparent synthetic resin such as polycarbonate is formed into a shape representing information, a reflection film made of, for example, an aluminum thin film is formed, whereby the recording layer 12 is formed. A second disk substrate 13 provided with a recording layer 14 as well as the first disk substrate 11 is placed thereon via an ultraviolet-curable resin 15 as an adhesive, and is irradiated with ultraviolet light. By curing the ultraviolet curing resin 15, the disk substrates 11 and 13 are bonded to each other.

The disk substrates 11 and 13 are respectively
At the center thereof, there are provided clamping center holes 11a and 13a for fixing and holding the optical disk 10 during recording or reproduction of the optical disk 10, and around the center holes 11a and 13a, so-called clamping zones 11b and 11b. 13b. The center holes 2a and 4a are formed, for example, so that the optical disc 1 has a diameter of 120 m.
In the case of m, the diameter is formed to be 15 mm.

On the other hand, the recording layers 12 and 14
It is formed on the surface of the disk substrates 11, 13 in a region between the clamping zone 2 b and the outer peripheral edge of the disk substrates 11, 13.

The above configuration is the same as that of the conventional optical disk 1 shown in FIG. 2. However, in the optical disk 10 according to the embodiment of the present invention, the two disk substrates 11 and 13 are bonded together. Surface, the periphery of the center holes 11a, 13a and the clamping zones 11b, 1
3b are provided with concave grooves 16 and 17 as annular adhesive pools in a region between the inner peripheral edges of the concave grooves 3 and 3b.
For example, when the optical disk 10 has a diameter of 120 mm,
It is formed in a region having a diameter of 16 mm to 17 mm.

Optical disc 10 according to an embodiment of the present invention
Is configured as described above, and the optical disc 10
After the first and second disk substrates 11 and 13 are overlapped with each other with the ultraviolet-curable resin 15 interposed therebetween, it is manufactured by curing the ultraviolet-curable resin 15 by irradiating ultraviolet rays.

At this time, as shown in FIG. 1, even if the amount of the UV-curable resin 15 applied is relatively large and extra UV-curable resin 15 flows inward toward the center holes 11a and 13a. , This extra ultraviolet curable resin 1
5 flows into the concave grooves 16 and 17 provided near the inner peripheral edge of the bonding surfaces of the disk substrates 11 and 13. Thereby, the extra ultraviolet curable resin 15
Are the center holes 11a of the disk substrates 11 and 13,
It does not protrude into 13a.

Accordingly, by applying a relatively large amount of the UV-curable resin 15, the UV-curable resin rotates over the entire surface between the disk substrates 11 and 13, so that the disk substrates 11 and 13 can be securely connected to each other. Since the ultraviolet curable resin 15 does not protrude into the center holes 11a and 13a, the optical disk 10 is securely held by the clamp member of the optical disk device during reproduction of the optical disk 10. The reproduction characteristics of the optical disc 10 are not impaired. Thus, the reproduction of the optical disk 10 is correctly performed.

In the above embodiment, the description has been given of a read-only optical disk in which information is recorded on a recording layer, but the present invention is not limited to this. Obviously, the present invention can be applied to a disk or the like.

As described above, according to the embodiment of the present invention, when the two disk substrates 11 and 13 are bonded by the ultraviolet-curable resin 15,
However, when the coating amount is large, the center hole 1
Even if it flows inward toward 1a, 13a, the UV curable resin 15 is prevented from flowing into the center holes 11a, 13a by flowing into the concave grooves 16, 17. Thus, if the application amount of the UV-curable resin 15 is set to be relatively large, the UV-curable resin 15 is not attached to the concave grooves 16 when the disk substrates 11 and 13 are bonded together, even if the application amount varies. ,
17, the disk substrates 11, 1
3 does not protrude into the center holes 11a and 13a. Therefore, the disk substrates 11 and 13 are securely bonded together, and the optical disk 10 formed by the bonding is correctly clamped by the clamp member of the optical disk device, so that the recording or reproduction of the optical disk is performed correctly. become.

[0022]

As described above, according to the present invention, an optical disk is provided in which an ultraviolet-curing resin for bonding a disk substrate does not protrude into a center hole of the disk substrate, thereby securely bonding the disk substrate. Can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of an embodiment of an optical disk according to the present invention.

FIG. 2 is a schematic sectional view showing a configuration of an example of a conventional bonded optical disk.

FIG. 3 is a schematic cross-sectional view showing a state in which an ultraviolet curable resin protrudes into a center hole in the optical disc of FIG. 2;

[Description of Signs] 10 optical disk, 11, 13 disk substrate, 11a, 13a center hole, 11b, 1
3b: Clamping zone, 12, 14: Recording layer, 15: UV curable resin, 16, 17: Concave groove (adhesive pool)

Claims (2)

[Claims] A plurality of disk substrates having a center hole for clamping at the center thereof, and formed on a surface of each disk substrate in a region between the clamping zone around the center hole and an outer edge. In the optical disk formed by bonding the recorded layer and each disk substrate, each disk substrate has an adhesive reservoir in a region between the center hole and the clamping zone on the bonding surface. An optical disc characterized by the above-mentioned. 2. The method according to claim 1, wherein the adhesive reservoir is formed by a concave groove, and the optical disc has a diameter of 120 mm.
2. The optical disk according to claim 1, wherein when the diameter of the center hole is 15 mm, the concave groove is provided in a region having a diameter of 16 to 17 mm.