JPH02254644A - Manufacture of optical disk - Google Patents

Abstract

PURPOSE:To remove a fine flash, to reduce a signal error and a appearance defect and to improve a quality, a yield and the profitability by rotating a substrate part forming a center hole part simultaneously while spraying a gas as necessary and rubbing cut surfaces with each other. CONSTITUTION:At the time of manufacturing a substrate 1 in an injection molding method, a center hole is punched in a metal mold 3 having a punching function, thereafter, a substrate part 1b forming a center hole part 4 is rotated at the time of a releasing from the metal mold 3, and the cut surfaces are rubbed with each other. At this time, simultaneously, the gas is blown-out through a gap 10 to the cut point of the disk substrate 1. Thus, since the fine flash of the center hole can be removed, the signal error and appearance defect due to the adhesion and mixture of the flash can be reduced, and the quality, yield and the profitability of the optical disk can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a read-only optical disc, for example, and in particular, to a method for manufacturing an optical disc that can improve quality9 yield and economic efficiency. It is about the method.

[Prior Art] Optical recording has advantages over magnetic recording in that there is no contact between the recording medium and the head, and high-density recording is possible. These optical recording media are known to be read-only, additionally writable, and erasable/rewritable. Read-only optical recording media (hereinafter referred to as optical disks) include: It has already been put into practical use in the form of compact discs and optical video discs. Usually, this type of optical disc is produced by creating a substrate with a center hole using a molding method such as injection molding, and then vapor-depositing it onto this substrate in the subsequent replication process.

A metal film surface (signal forming surface) is provided by a method such as sputtering, a protective layer is further coated on the metal film surface, and a label is printed on the protective layer.

[Problems to be Solved by the Invention] Incidentally, in the production of such conventional optical discs, the punching area is locally made thinner during molding of the substrate, and the stroke of the punching cutter is shortened to reduce the thickness of the cut surface. The center hole is moved directly to avoid excessive rubbing, and there is no need to perform any special finishing treatment on the center hole, and during the replication process, fine particles remain in the fabrication process. For this reason, the particles remaining in the center hole may cause foreign matter to adhere to the reflective film or signal forming surface during the replication process, resulting in signal errors or poor appearance, or when the protective coating is removed. Foreign matter may be mixed in during label printing, resulting in poor appearance, resulting in a decrease in the quality of the optical disc, a decrease in yield, and furthermore, an increase in costs.

The present invention has been made to solve the above-mentioned problems, and it reduces signal errors and appearance defects caused by the adhesion and contamination of minute particles in the center hole, and significantly improves quality yield and economic efficiency. It is an object of the present invention to provide a method for manufacturing an optical disc that can achieve the following objectives.

[Means for Solving the Problems] In order to achieve the above object, in the first invention, when manufacturing an optical disc substrate by plastic molding, a center hole is punched out by a punching process, and then the center hole is punched out. The substrate portion forming the hole portion is rotated while blowing gas at the same time as necessary so that the cut surfaces rub against each other. When manufacturing, a center hole is punched out in a mold with a punching function, and then the part of the substrate that had formed the center hole part when released from the mold is rotated while blowing gas at the same time as necessary. This allows the cut surfaces to rub against each other.

[Function] Therefore, in the present invention, the substrate portion that formed the center hole portion is rotated while blowing gas at the same time as necessary, so that the cut surfaces rub against each other, thereby eliminating the fine details of the center hole. It is possible to remove such particles, reduce signal errors and appearance defects caused by the particles, and significantly improve the quality and economical efficiency of optical discs.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a specific configuration example for realizing the optical disc manufacturing method according to the present invention, and here, the case where an injection molding method is applied is shown.

In FIG. 1, a disk-shaped disk substrate 1 has its punched portion 1a locally formed thinly as shown in the figure, and is placed with the signal forming surface formed by the stub bar 2 facing downward. Further, this disk substrate 1 is housed, as shown in the figure, in a mold 3 for injection molding, for example, consisting of a fixed mold 3a and a movable mold 3b. Furthermore, a disk-shaped disk substrate 1
On the upper side of the board, which will become the center hole part 4, is a sprue 5. A cold slug well 8° and a punching bunch 9, which are fitted and held by a sprue ejector 7, are arranged on the lower side of the substrate. Here, the cold slug well 8 has a taper so as to be easily released from the mold, and has a rectangular cross section so as to be able to transmit rotational driving force. Note that 10 is a gas jetting gap for jetting gas, for example, air, nitrogen, etc., to the punched portion 1a of the disk substrate 1 from the lower side in the figure.

Next, a method for manufacturing an optical disc based on the above configuration will be described.

Now, when manufacturing the substrate 1 of an optical disk by injection molding, a center hole is first punched out using a punch 9 in a mold 3 having a punching function. next,
The mold is released from the mold 3. At the time of the mold release, the substrate portion 1b forming the center hole portion 4 is rotated in the direction A as shown in FIG. 2, and the cut surfaces are rubbed against each other.

This prevents the scraped Paris powder from adhering to the inside of the mold 3 or to the disk substrate 1. At this time, the center hole portion 4 is rotated and at the same time, gas is blown onto the cut portion 1c of the disk substrate 1 through the gas ejection gap 10. Thereby, adhesion of paris powder can be prevented even more effectively.

As described above, in this embodiment, when manufacturing an optical disc substrate by injection molding, a center hole is punched out in a mold 3 having a punching function, and then when the mold 3 is released from the mold 3, a center hole is punched out. Rotating the substrate portion 1b that had formed the hole portion 4 and rubbing the cut surfaces together,
At the same time, gas is blown onto the cut portion IC of the disk substrate 1 through the gas jetting gap 10.

Therefore, fine particles in the center hole can be removed by rubbing the cut surfaces together, reducing signal errors and appearance defects caused by particle adhesion and contamination, and improving the quality, yield, and economy of optical discs. It is possible to significantly improve this.

In the above embodiments, the present invention is applied to a substrate for an optical disc manufactured by an injection molding method, but the present invention is not limited to this, and may be applied to, for example, an injection compression molding method, a compression molding method, a 2P method, or other methods. The present invention can be similarly applied to products manufactured by the above molding method.

Furthermore, in the above embodiment, when rotating the substrate portion 1b forming the center hole portion 4, a case was described in which gas was simultaneously blown onto the cut portion IC of the disk substrate 1, but this is not necessarily essential to the present invention. It's not a good method.

[Effects of the Invention] As explained above, according to the present invention, it is possible to reduce signal errors and appearance defects due to the adhesion and contamination of minute particles in the center hole, and to significantly improve quality and economical efficiency. It is possible to provide a method for manufacturing an optical disc that enables the following.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic diagram showing an embodiment of the method for manufacturing an optical disc according to the present invention, and FIG. 2 explains the method for manufacturing an optical disc in the same embodiment. This is a partial diagram for. 1...Disc board, 1a...Punching location, IC/
...Cutting location, 2...Stamper 3...Mold, 3a
...Fixed side mold, 3b... Movable side mold, 4... Center hole part, 5... Sprue 6... Bush, 7... Ejector for sprue, 8... Cold slug Well, 9... punch for punching, 10... gap for gas ejection. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (4)

[Claims] (1) In a method of manufacturing the substrate of an optical disk by plastic molding, a center hole is punched out by a punching process, and then the portion of the substrate that formed the center hole is rotated to rub the cut surfaces together. A method for manufacturing an optical disc, characterized by: (2) The method for manufacturing an optical disc according to claim (1), wherein gas is simultaneously blown when the substrate portion forming the center hole portion is rotated. (3) In a method of manufacturing a substrate for an optical disk by a predetermined molding method, a center hole is punched out in a mold having a punching function, and then the substrate forming the center hole portion is released from the mold. A method for manufacturing an optical disc, characterized in that the parts are rotated so that the cut surfaces rub against each other. (4) The method for manufacturing an optical disc according to claim (3), wherein gas is simultaneously blown when the substrate portion forming the center hole portion is rotated.