JP2745765B2 - Manufacturing method of optical recording medium - Google Patents

Description

The present invention relates to a method for manufacturing an optical recording medium such as an optical disk (compact disk), a video disk, an optical card, etc., and particularly to shortening the manufacturing time. The present invention relates to a method for manufacturing an optical recording medium to be obtained.

[Prior Art] Optical recording has advantages over magnetic recording in that a recording medium and a head are not in contact with each other and high-density recording is possible. As this optical recording medium, a read-only medium, an additionally writable medium, and an erasable / rewritable medium are known. As the optical recording medium according to the present invention, an optical disk (compact disk) is already used. And optical video cards, optical cards and the like have already been put to practical use.

By the way, the following method has conventionally been adopted as a method of manufacturing this type of optical recording medium.

(A) A method in which a pit or pregroove signal is transferred and formed on a resin substrate by using a stamper, a reflective film layer or a recording film layer is formed on the signal surface by vapor deposition, and a protective layer is formed thereon by coating ( (Batch method) (b) A method in which a resin film or sheet on which a pit or pregroove signal is recorded is bonded to a sheet-like transparent substrate using an adhesive, and then punched into a predetermined shape. A method in which a resin film or sheet on which a pregroove signal is recorded is punched into a predetermined shape and bonded to a transparent substrate formed in a predetermined shape in advance using an adhesive. However, such a conventional manufacturing method has the following various problems.

First, in the method (a), a dedicated machine must be used for vapor deposition of the reflective film layer or the recording film layer, and the cost is high and the throughput is low. When recording a pit or pre-groove signal by injection molding, However, when the injection speed is increased, there is a problem that transferability is deteriorated. In the methods (b) and (c), a step of applying an adhesive is required when bonding the resin film or sheet to the transparent substrate. There is a problem that air bubbles and dust are liable to be mixed when combined.

Due to the problems described above, the injection speed cannot be increased, resulting in a longer manufacturing time, or a defect in the recording section, which lowers the reliability of the optical recording medium.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and aims to shorten the manufacturing time by increasing the injection speed and to improve the reliability by preventing defects from occurring in the recording unit. It is an object of the present invention to provide a method of manufacturing an optical recording medium capable of performing the following.

[Means for Solving the Problems] In order to achieve the above object, according to the present invention, a film in which a pit or pregroove signal is recorded on one side inside a molding cavity formed by a split mold is provided. A sheet is provided, and a molten resin is injection-molded on the side of the film or sheet opposite to the signal side.

[Operation] Therefore, in the method for manufacturing an optical recording medium of the present invention, a film or sheet on which pit or pre-groove signals are recorded in advance is formed, and there is no need to transfer pits or pre-grooves. As a result, the injection speed can be increased and the manufacturing time can be shortened. In addition, by disposing a film or sheet inside the molding cavity and injecting and molding a molten resin on the side opposite to the signal side of the film or sheet, air bubbles and dust are prevented from being mixed, and the optical recording medium is eliminated. Reliability can be increased.

Embodiment Hereinafter, an embodiment of the embodiment will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing a configuration example for realizing a manufacturing method when the present invention is applied to an optical disk.

In FIG. 1, a two-piece mold, that is, a first mold A including a first mold 11 and a first platen 21,
The molding cavity 3 is formed by the second mold B including the second split mold 12 and the second platen 22. Here, the first platen 21 and the second platen 22 include:
Cooling water channels 41 and 42 through which the cooling water flows are provided as shown.

On the other hand, inside the molding cavity 3, a film or sheet 5 on which a pit or pre-groove signal is recorded in advance by transfer on one side is arranged, and the film or sheet 5 is fed by a feed roller 6 to the molding cavity 3. It can be sent continuously inside. Further, an outer periphery punching cutter 7 and a center punching punch 8 are provided as shown in the figure by penetrating the second die B. Further, an injection path 9 penetrating the first mold A and communicating with the molding cavity 3 from outside the mold is provided as shown in the figure.

The molten resin to be injected is at a high temperature and the shape of the pits or pre-grooves is deteriorated.
Contact with 22.

The optical disk of this embodiment is manufactured as follows.

That is, first, the cooling water is circulated in advance through the cooling water passages 41 and 42 of the first platen 21 and the second platen 22 constituting the mold.

Next, a film or sheet 5 on which a pit or pre-groove signal is recorded on one side in advance is supplied to the inside of the molding cavity 3 by a feed roller 6 outside the mold and arranged.

Next, the molten resin is injection-molded from the outside of the mold through the injection path 9 to the film or sheet 5 disposed inside the molding cavity 3 on the side opposite to the signal side (the right side in the figure). .

Thereafter, punching is performed by the outer peripheral punching cutter 7 and the center punching punch 8 to obtain an optical disk having a center hole and a predetermined radius.

Here, as the material of the film or sheet 5, generally, a resin having heat resistance, for example, a polyester resin, a polycarbonate resin, a vinyl chloride resin, an acrylic resin, or a laminate thereof can be used. And
Due to properties such as surface smoothness and heat resistance, thickness is 10μm ~ 500μ
m (preferably 30 μm to 150 μm) is most preferably used. In this example, the thickness is 100 μm
Is used.

The signal of the pits or pregrooves is obtained by superimposing the surface of the stamper, that is, the signal master on one side of the film or sheet 5 by a roll press machine, performing heating and pressing, and then cooling. A pit or pre-groove signal is formed by embossing. In this case, flat pressure press, circular pressure press,
Alternatively, any of the rotary printing methods can be used. Also,
The depth of the pit or pre-groove is 0.05-0.2
μm. In this example, pits having a depth of 0.12 μm are transferred by hot pressing using a stamper.

Further, as the reflective film, a metal such as aluminum, aluminum alloy, copper, copper alloy, gold, silver, platinum, nickel or the like, for example, a sputtering method using a vacuum chamber, a vacuum evaporation method, an ion plating method or the like. By
The thickness is set to 0.06 μm or more to obtain a specified reflectance. In this example, a reflective film of aluminum having a thickness of 0.1 μm is provided.

On the other hand, as the molten resin, a thermoplastic resin such as a polycarbonate resin, an acrylate resin, and an amorphous polyolefin resin can be used. In this example, 300-4
Using a polycarbonate resin heated to about 00 ° C,
It is formed to a thickness of 1.1 mm, and is 1.2 mm including the thickness of the film or sheet 5.

The temperature T1 of the first mold A and the temperature T2 of the second mold B
Is preferably set to satisfy T1 ≧ T2. In this example, the temperature T1 of the first mold A is kept at about 100 ° C., and the temperature T2 of the second mold B is kept at about 50 to 80 ° C. in order to prevent the temperature of the signal surface from rising.

Further, in the punching process using the outer peripheral punching cutter 7 and the center punching punch 8, the outer diameter Φ is 120 mm in this example.
Then, the inner diameter Φ is punched to a size of 15mm.

In the method of manufacturing an optical disc as described above,
Since the film or sheet 5 on which the pit or pre-groove signal is recorded in advance and there is no need to transfer the pit or pre-groove, the injection speed can be increased and the manufacturing time can be shortened. In addition, since the film or sheet 5 is disposed inside the molding cavity 3 and the molten resin is injection-molded on the side of the film or sheet 5 opposite to the signal surface, air bubbles and dust are prevented from being mixed. Thus, the reliability as an optical recording medium can be improved.

As described above, in the present embodiment, a film or sheet 5 on which a pit or pre-groove signal is recorded on one side is disposed inside a molding cavity 3 formed by split molds A and B. Alternatively, a molten resin is injection-molded from the outside on the side opposite to the signal side of the sheet 5.

Therefore, the following various functions and effects can be obtained.

(A) Compared to the conventional method of bonding a film or sheet on which a pit or pre-groove signal is recorded on one side and a transparent substrate with an adhesive, molten resin is injection-molded. It is possible to eliminate trash.

(B) Compared with the conventional method of transferring pits or pre-grooves by injection (batch method), it is necessary to form a film or sheet 5 on which pit or pre-groove signals are recorded in advance and consider transferability. Therefore, the tact time can be increased. Also,
Since the reflective film layer and the recording film layer are deposited in the form of a film or sheet, the tact time can be increased as compared with the batch method.

As a result, the injection speed is increased to shorten the manufacturing time, and the recording unit is free from defects.
The reliability as an optical disk can be significantly improved.

In the above embodiment, the case where the pit or pre-groove signal is recorded on one surface of the film or sheet by the roll press method is described. However, the present invention is not limited to this. For example, the pit or pre-groove signal is recorded by the hot press method, the 2P method, or the like. May be recorded.

In the above embodiment, the signal surface of the pit or pregroove may be protected by a protective film (for example, an acrylate resin film having a thickness of 6 to 7 μm).

Further, in the above embodiment, the case where the present invention is applied to an optical disc has been described. However, the present invention is not limited to this, and the present invention can be similarly applied to, for example, a card-shaped recording medium (optical card). .

[Effects of the Invention] As described above, according to the present invention, a film or sheet on which a pit or pre-groove signal is recorded on one side is disposed inside a molding cavity formed by a split mold. Since the molten resin is injection-molded on the side opposite to the signal side of the film or sheet, the injection speed is increased to shorten the manufacturing time,
It is possible to provide a method of manufacturing an optical recording medium capable of improving reliability without causing a defect in a recording section.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment for realizing a manufacturing method when the present invention is applied to an optical disk. A ... first mold, 11 ... first split mold, 21 ... first platen, B ... second mold, 12 ... second split mold, 22 ...
Second platen, 3 ... Mold cavity, 41, 42 ...
Cooling water channel, 5: film or sheet, 6: feed roller, 7: outer peripheral punching cutter, 8: center punching punch, 9: injection path.

Claims (4)

(57) [Claims] 1. A film or sheet on which a pit or pregroove signal is recorded on one side is disposed inside a molding cavity formed by a split mold, and is opposite to the signal side of the film or sheet. A method for producing an optical recording medium, wherein a molten resin is injection-molded on a surface side. 2. The method of manufacturing an optical recording medium according to claim 1, wherein the molten resin is a thermoplastic resin such as a polycarbonate resin, an acrylate resin, and an amorphous polyolefin resin. Method. 3. The method according to claim 1, wherein a signal surface of the pit or the pregroove is protected by a protective film. 4. The method for producing an optical recording medium according to claim 1, wherein said film or sheet is in the form of a disk or a card.