JPH0831023A - Production of disk without having through-hole in central part and production of disk having small-diameter through-hole in central part and the disk - Google Patents

Abstract

PURPOSE:To enable recording of data up to the neighborhood of the central part of a disk. CONSTITUTION:The surface opposite to the data information recording region of a stamper I recorded with data signals, etc., up to the neighborhood of the central part, is sucked and fixed to a movable mold A by the effect of the vacuum of a suction port 6. After the mold is clamped togethe with a stationary mold B, a thermally melted molding material is injected from an injection port 5 and the data signals, etc., recorded on the stamper 1 by the injection pressure of this time are transferred to the molding material. The molding material is then cured by cooling to obtain a replica disk 2. The replica disk 2, i.e., the optical disk, is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk such as an optical disk, an optical-magnetic disk, etc., characterized in that a data recording area is provided up to the vicinity of the center of the disk having no through hole in the center, and a method of manufacturing the same. It is about.

[0002]

2. Description of the Related Art In recent years, as a recording medium for recording digital data such as audio, video, image and computer data,
Optical discs are becoming mainstream. There are various sizes of optical discs depending on the recording medium.
The disk represented by the sound is 120 mm or 80 mm
mm compact disc, 300 mm laser disc for images, 120 mm longitude for computer data, etc.
CD-ROM and the like exist.

As a method of manufacturing an optical disc having no through hole in the center portion of this kind, generally, a stamper on which data is recorded is sealed in a molding material such as a resin melted by heat and a mold, and the recorded data is recorded. There is a method by an injection molding method called injection-compression method for obtaining a predetermined optical disc by transferring to a molding material, and this method is called a mold as disclosed in Japanese Patent Publication No. 61-34370. Alternatively, it is formed using a structure similar to this. An example of an optical disc molded by such a method is shown in FIG.

FIG. 9 is a plan view of a compact disc molded by a general injection molding method.

As shown in FIG. 9, for the area of the information recording area 31 in the shaded area of the disk body 30, most of the molds used for mass production have an inner diameter defined by the International Electrotechnical Commission IEC. The punching of the through hole 32 having a diameter of 15 ± 0.1 mm (for compact disc) or 35 ± 0.1 mm (for laser disc) is performed during molding.

[0006]

However, in a diversifying multimedia, a recording medium which becomes compact as the amount of information expands and data is recorded up to the central portion of a disk which has not been recorded before. The focus was on increasing the recording capacity per disc. Furthermore, when the diameter of the disc is reduced and the necessity for an ultra-small disc of about 20 mm to 30 mm or less arises, a hole is not formed in the center of the disc, and a request for an optical disc in which data is recorded near the center is required. May occur.

Particularly, as an example of a commercially available video disc, as shown in the perspective view of the plane layout of the known video disc of FIG. 10, the outer diameter = 300 mm, the maximum diameter of the information recording area = 290 mm, the information recording area. The minimum diameter is 110 mm, the outer diameter of the label is 93 mm, and the through hole is 35 mm. Here, even if the outer diameter is 300 mm, the maximum diameter of the information recording area, that is, the lead-out RO is 290 mm,
The minimum diameter of the information recording area, that is, the lead-in RI is 110
The information recording area is 8 mm of the total area of the disc.
Only about 0 percent area is used.
Further, the utilization rate is further reduced for compact discs and mini discs having a smaller diameter. Therefore, it is necessary to increase the effective use area of the information recording area.

Therefore, according to the present invention, the central hole for clamping found in the conventional disc is deleted so that the data can be recorded up to the vicinity of the central portion of the disc, and the data can be recorded even in that portion. It is an object of the present invention to provide a method of manufacturing a disk having no through hole in the center, a method of manufacturing a disk having a small diameter through hole in the center, and a disk as much as possible.

[0009]

According to a first aspect of the present invention, there is provided a method of manufacturing an optical disc having no through hole in a central portion thereof, wherein one side of the stamper having data recorded on the transfer surface excluding the central portion is opposite to the transfer surface. A step of mounting the die on a surface and restraining the outer periphery thereof, and a step of clamping the other die having an injection port for injecting a molding material at a substantially central position with the die to which the stamper is attached, And a step of injecting a molding material from an injection port at a substantially central position of the mold to mold a disc-shaped disc.

According to a second aspect of the present invention, there is provided a method of manufacturing an optical disc having no through hole in the center thereof, in which the surface opposite to the transfer surface of the stamper on which data is recorded is attached to the mold by suction. It is a thing.

According to a third aspect of the present invention, there is provided a method of manufacturing a disk having a small-diameter through hole in a central portion, which comprises a step of surface-attaching a side of a stamper on which data is recorded up to the vicinity of the central portion to one mold. A step of clamping the other die having an injection port for injecting the molding material at a substantially central position with the die to which the stamper is attached, and injecting a molding material from the injection port at the approximately central position of the die. And forming a disc-shaped disc.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a disc having a small-diameter through hole in the center thereof, wherein the stamper on which data is recorded on the transfer surface is attached to the mold by suction. It is a thing.

A disk according to a fifth aspect comprises a disk-shaped disk main body and an information recording area formed on one surface of the disk main body and capable of reading information by reflecting laser light. In the provided disc, the recordable area of the information recording area is set to about 85% or more.

According to a sixth aspect of the present invention, a disc having no through hole in the center is formed on a disc-shaped disc body and one surface of the disc body, and information is read out by reflecting a laser beam. In a disc having a recordable information recording area, the recordable area of the information recording area is set to about 85% or more.

According to a seventh aspect of the present invention, a disk having a small-diameter through hole in the center is formed on a disk-shaped disk body and the surface on one side of the disk body, and information is read by reflecting laser light. In a disc having a recordable information recording area, the recordable area of the information recording area is set to about 85% or more.

According to an eighth aspect of the present invention, in the information recording area of the disc, the start position of the information recording is near the center of the disc.

[0017]

According to the present invention, the opposite side of the transfer surface of the stamper having data recorded on the transfer surface excluding the central portion is attached to one of the molds, and the injection port for injecting the molding material is provided substantially at the center. The die is clamped with the other die to which the stamper is attached, and a molding material is injected from an injection opening at the substantially center of the die,
Mold an optical disk without a central hole.

In the second aspect, the stamper is attached by suction in the step of attaching the opposite side of the transfer surface of the stamper of the first aspect to the mold.

According to a third aspect of the present invention, the stamper on which data is recorded on the transfer surface excluding the center portion is attached to one of the molds, and an injection port for injecting a molding material is provided at substantially the center. The die is clamped with the other die to which the stamper is attached, and a molding material is injected from an injection opening at the substantially center of the die,
A disk having a small diameter through hole in the center is molded.

According to a fourth aspect of the present invention, the stamper is attached by suction in the step of attaching the opposite side of the transfer surface of the stamper of the third aspect to the mold.

According to a fifth aspect of the present invention, the information recording area formed on one surface of the disk body and capable of reading information by reflecting laser light is set to about 85% or more, and its storage capacity is set. To increase.

According to a sixth aspect of the present invention, the information recording area which is formed on one surface of the disk body having no through hole in the central portion and which enables the reading of information by reflecting the laser beam is about 85%. The above setting is made to increase the storage capacity.

According to a seventh aspect of the present invention, an information recording area which is formed on one surface of the disk body having a small-diameter through hole in the central portion and which enables information to be read by reflecting laser light is about 85%. The above setting is made to increase the storage capacity.

In the eighth aspect, the recording area can be formed up to the center of the disk-shaped disc body.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the disk manufacturing method of the present invention will be described below with reference to the drawings.

FIG. 1 is a structural diagram of a mold for explaining a method of manufacturing an optical disc having no through hole in the center thereof according to an embodiment of the present invention. 2 to 7 are explanatory views showing a process of forming a disc by the mold shown in FIG.
Is a state in which the movable die and the fixed die are open, FIG. 3 is a state in which the movable die and the fixed die are closed, FIG. 4 is an injection / cooling state, FIG. 5 is a state in which the movable die and the fixed die are open, and FIG. It is explanatory drawing which shows an extraction state.

In FIG. 1, reference numeral 1 is a stamper in which data is recorded even in the vicinity of the central portion, and 2 is a replica disk which is an optical disk of a molded product. 3 is stamper 1
Movable type A having a movable side mirror block 3 having a mirror surface 3a for holding the outer periphery of the stamper 1 by suction and fixing the stamper 1.
And a fixed mold B having a fixed-side mirror block 4 having a mirror surface 4b from which the heat-melted molding material is injected, 5 is an injection port for injecting the heat-melted molding material, and 6 is a mirror surface 3a of the movable-side mirror block 3. It is a stamper suction port for sucking and fixing the stamper 1 by vacuum vacuum or the like. Here, the injection port 5 connected to the injector nozzle is for injecting the molding material, is formed in the center of the fixed mold B, and communicates with the fixed-side mirror block 4.

Next, with reference to FIGS. 2 to 6, a process of forming a disc of an optical disc according to an embodiment of the present invention will be described.

First, in a state where the two molds, that is, the movable mold A and the fixed mold B are opened (FIG. 2), the stamper 1 is operated by the vacuum vacuum of the stamper suction port 6 to transfer the data (information recording area). ) Is attached to the mirror surface 3a of the movable-side mirror block 3 of the movable die A by suction. Then, the movable die A is slid toward the fixed die B, and both dies are abutted to be integrated (FIG. 3). Then, a heat-melted molding material, for example, a resin such as polycarbonate is injected into the injection port 5.
Eject more (Fig. 4). When the void 7 formed by the mirror surface 3a of the movable mirror block 3 of the movable mold A and the mirror surface 4b of the fixed mirror block 4 of the fixed mold B is filled with the molding material, the injection pressure of the molding material at that time causes The data recorded on the stamper 1 is transferred to the boundary surface between the stamper 1 and the molding material. It is then cooled to cure the molding material.

After that, the movable mold A moves to the left side in the figure,
The mold is opened (FIG. 5), the data recorded on the stamper 1 is transferred, and the replica disc 2 having no hole in the center, that is, the optical disc is taken out (FIG. 6).

FIG. 7 shows an example of an optical disk having no through hole in the central portion thus taken out.

FIG. 7 is a plan view of an optical disk manufactured by the method of manufacturing an optical disk having no through hole at the center according to an embodiment of the present invention.

In FIG. 7, the hatched area on the plane of the optical disk body 10 is an information recording area (recording surface or transfer surface) 11 on which the data recorded on the stamper 1 is transferred. In this area, data is recorded up to the central portion. However, only the central portion 12 of the extremely polar center is a region where no data is recorded, and has a diameter of about 0.5 mm here. In this embodiment, the data recording can be brought as close as possible to the central portion 12. However, when reading data from the optical disc, this numerical value cannot be unconditionally specified because it depends on the reading accuracy of the optical pickup and the hardware configuration of the reproducing apparatus.

Next, the increase of the recording area between the replica disc formed by the method of manufacturing an optical disc having no through hole at the center of the present invention and the conventional optical disc will be described with reference to FIGS. 7 and 9. .

In FIG. 9, for example, in the case of a conventional compact disc, the information recording area indicated by the shaded area is the International Electrotechnical Commission (IEC908; 198).
7) and Japanese Industrial Standards (JIS S-8605-199)
According to the standard of 3), the recording start position has a radius of 2 from the center.
At 2.5 mm, the memory end position is a radius of 58.5 m from the center
m. Therefore, the area of the information recording area is about 916.
It will be 1 mm ² . On the other hand, in the information recording area of the embodiment of the present invention, as shown in FIG. 7, if the recording start position has a radius of 0.25 mm from the center and the recording end position has a radius of 58.5 mm from the center, The area of the information recording area is about 10751 mm ² , which is about 17% larger than that of the conventional disk. Therefore, in the case of music, the number of songs increases by 3 to 4, and the recording area is further expanded.

As described above, the step shown in FIG. 2 in which the opposite side of the transfer surface of the stamper, on which data is recorded on all transfer surfaces except the central portion, is attached to one of the molds, for example, the movable mold A, and the molding material. The step shown in FIG. 3 in which the other mold made of the fixed mold B having the injection port 5 for ejecting the mold is clamped to the mold made of the movable mold A to which the stamper 1 is attached, and the mold shown in FIG. The process shown in FIGS. 4 to 6 in which a molding material is injected from an injection port substantially at the center of the mold to form an optical disk having no through hole in the center, is provided. Can be used as an example.

Therefore, data is recorded except for a part of the center of the stamper 1, the surface on the opposite side of the data information recording area is suction-fixed to the movable mold A by the action of vacuum vacuum, and the ejection port 5 is incorporated. The mold is clamped with the other fixed mold B, and at this time, the molding material in which the injection port 5 has been melted by heat is injected from the injection port 5 and then cooled, and the molding material is hardened, and then recorded on the stamper 1. It is possible to take out the optical disc having the transferred data.

At this time, since the injection port 5 is located at the center of the stamper 1, the injection pressure is dispersed over the entire circumference, and the specific vector force does not become large. Therefore, the stamper 1 does not move and the injection molding is performed. Is possible. Of course, ejection port 5
Is ideally located at the center of the stamper 1, but a plurality of injection ports may be set, or the injection port 5 may be set at a substantial center slightly deviated from the center. That is, the same effect can be expected in the fixed mold 4 having the ejection port 5 at the substantially center.

In the embodiment of the present invention, the stamper 1 is attracted to the mirror surface 3a of the movable mirror block 3 of the movable mold A, and this can be the embodiment of claim 2. In particular, since the movement of the outer periphery of the stamper can be restricted by the movable-side mirror block 3, it is possible to securely fix the outer periphery of the stamper at the time of release by suction. In particular, in this embodiment, since it is fixed by suction, the stamper 1 is fixed to the mirror surface 4b of the fixed-side mirror block 4 of the fixed mold B, and the exit 5 is communicated with the movable-side mirror block 3 of the movable mold A. The method can also be applied.

Further, in FIG. 1, since there is no through hole at the center of the optical disc as in the conventional case, the structure of the movable die B can be simplified, and the movable die A is molded into a plurality of discs. With such a structure, it is possible to form optical disks of different data by using a plurality of stampers 1 having the same contents or various kinds in one injection molding process.

According to the disk manufacturing method of the present embodiment, which does not have the through hole 32 in the central portion, the through hole 32 is not formed in the central portion of the optical disk to be molded. It can be sufficiently applied to the standard of an optical disc having no through hole at the center of the diameter or having a fine through hole at the center.

That is, a central portion including a disc-shaped optical disc body 10 and an information recording area 11 formed on one surface of the optical disc body 10 and capable of reading information by reflecting laser light. In the disc having no through-hole, the information recording area 11 has a lead-in RI (0.5 mm) and the same lead-out R as the conventional one.
If O (290 mm) is set, the area of the information recording area 11 becomes about 93% or more, and the storage capacity in track units is further increased. That is, even if the position of the lead-in RI is slightly enlarged, at least the area of the information recording area 11 can be set to about 85% or more. This can be the embodiment of claim 6.

Therefore, the storage area can be expanded with a single disk, and the storage capacity can be further increased by increasing the recording density. In particular, the management of the disc becomes easy by making the area from the lead-in RI to a predetermined area a management information area such as an index.

However, when the present invention is carried out, since the size of the diameter leading to the lead-in RI does not matter, it can be used as a disc other than a disc having no through hole in the central portion. For example, it can be used for a disk having a small-diameter through hole at the center, and this can be the embodiment of claim 7. Alternatively, even if the through holes 32 having a diameter of 35 ± 0.1 mm are formed as in the conventional case, it is possible to obtain an information recording area of about 87%, which is the embodiment of claim 5. it can.

In particular, it is possible to effectively use the outside of the information storage area of a disc having no through hole in the center and a disc having a small diameter through hole in the center.

By the way, in the above-mentioned embodiment, although the through hole 32 of the conventional example is not provided in the central portion of the optical disk, the presence or absence of the through hole 32 can make the flow of the injected molding material uniform and the central portion. It can be used as a data area up to the immediate vicinity.

However, in the case of carrying out the present invention, the through hole 32 has a small diameter regardless of the presence or absence thereof.

That is, according to the method for manufacturing a disk having a small diameter through hole in the center of this embodiment, the side opposite to the transfer surface of the stamper 1 having data recorded on the transfer surface excluding the center is transferred from one movable mold A. Fixed die B having the step of attaching the die to the die by a surface and the injection port 5 for injecting the molding material at the substantially central position.
And a step of clamping the die including the die with the die to which the stamper 1 is attached, and a step of injecting a molding material from an injection port 5 at a substantially central position of the die to form a disc. This is an embodiment of claim 3.

In addition to the effects of the above-mentioned embodiment of claim 1,
In particular, in this type of embodiment, a disk having a small diameter through hole at the center can also have a small diameter through hole formed in the center of the corresponding stamper 1, which can also be used for positioning the stamper 1. At this time, the ejection port 5 may be deviated from the center to be located at the substantially central position, or a plurality of the ejection ports 5 may be arranged around the center of the ejection port 5. Further, the small-diameter through hole at the center of the disk can be processed by punching when removing the gate after molding the disk.

Also in the embodiment of the present invention, the stamper 1 is attracted to the mirror surface 3a of the movable mirror block 3 of the movable mold A, and this can be the embodiment of claim 4. In particular, since the movement of the outer periphery of the stamper 1 can be restricted by the movable mirror block 3 of the movable die A, it is possible to securely fix the outer periphery of the stamper 1 at the time of release by suction. In particular, in the present embodiment, since it is fixed by suction, it can be applied to a method in which the stamper 1 is fixed to the mirror surface 4b of the fixed-side mirror block 4 of the fixed mold B, and the ejection port 5 is set to the movable mold A. Is.

From the optical disk body 10, a mold made of one movable mold A to which the stamper 1 on which data is recorded is fixed and a mold made of the other fixed mold B having an injection port for injecting a molding material are used. Get a replica disc with a large diameter. Thereafter, the outer periphery of the disc having a high birefringence is cut off by cutting the outer periphery with a receiving blade before the replica disc has cooled sufficiently.
It is also possible to obtain an optical disc in which the outer peripheral portion of a predetermined size is cut with a uniformly low birefringence.

Therefore, a disc having a diameter of a predetermined value or more is obtained by injection molding by one mold having the stamper 1 on which data is recorded fixed and the other mold having an injection port for injecting the molding material. Since the outer peripheral portion of the disc is cut so that the disc obtained by injection molding has a predetermined diameter, by cutting the outer peripheral portion, an optical disc of a predetermined size having a uniformly low birefringence can be obtained. Obtainable. Therefore, the outer peripheral portion of the disc is cut off from the outer peripheral portion of the disc where internal distortion of the molding material is most likely to occur, so the overall birefringence is low and stable, and the recording area extends to the outer peripheral portion of the disc. Can be expanded. In particular, when the information recording area is insufficient and another disc must be used, the expansion of the recording capacity will satisfy the requirement.

Although the optical disk has been described in the above embodiments, the present invention is not limited to the optical disk, and can be used in general disks such as optical disks and optical-magnetic disks, and can be spiral or virtual. It can also be a track on a concentric circle of the central axis.

The reading in the disc of the above embodiment includes reading out of a disc capable of recording and reproducing and reading out of a disc capable of reproducing only.

[0055]

As described above, according to the method of manufacturing an optical disc having no through hole in the central portion of the first aspect, one side of the stamper having data recorded on the transfer surface except the substantially central portion is opposite to the transfer surface. Attached to the mold, has an injection port for injecting a molding material in the center, and clamps the other mold to which the stamper is attached, injects a molding material from the injection port in the center of the mold, An optical disk without a central hole is formed.

Therefore, since the injection port is located substantially at the center of the stamper, the injection pressure is dispersed over the entire circumference, and the vector force in a specific direction does not act, so that injection molding can be performed without moving the stamper. . Since data can be recorded up to the center of the molded disc, data can be recorded up to the center of the disc, and the storage area is expanded.

Further, since no through hole is formed in the disk and the disk can be uniformly molded, the distortion is smaller and the birefringence characteristic is improved as compared with the conventional one. In addition, the gate has a pinpoint shape, and it is difficult for material loss and strain at the time of cutting the material to enter. Further, a mechanism for punching (cutting) the through hole is not required, so that the mold can be simplified and a plurality of moldings can be performed at the same time.

According to a second aspect of the present invention, there is provided a method of manufacturing an optical disc having no through hole at the center thereof, wherein the stamper is attached by suction in the step of attaching the opposite side of the transfer surface of the stamper to the mold. Therefore, in addition to the effect of the first aspect, the movement of the outer periphery can be regulated by the mold, so that the fixing at the time of releasing can be surely performed by suction.

According to a third aspect of the present invention, there is provided a method of manufacturing an optical disc having a small diameter through hole in the center thereof, wherein the stamper having data recorded on the transfer surface excluding the center is attached to one mold on the opposite side of the transfer surface. Which has an injection port for ejecting, and is clamped with the other mold to which the stamper is attached, and a molding material is injected from the injection port at the center of the mold to form an optical disc without a central hole. To do.

Therefore, since the injection port is located substantially at the center of the stamper, the injection pressure is dispersed over the entire circumference, and the vector force in a specific direction does not act, so that injection molding can be performed without moving the stamper. . Since data can be recorded up to the center of the molded disc, data can be recorded up to the center of the disc, and the storage area is expanded.

Further, in the disk having the small diameter through hole at the center, the small diameter through hole can be formed at the center of the corresponding stamper, and it can be used for positioning the stamper. At this time, it is possible to deviate the ejection port from the center to a substantially central position, or to dispose a plurality of units around the center of the ejection port. Further, the small-diameter through hole at the center of the disk can be processed by punching when removing the gate after molding the disk.

According to a fourth aspect of the present invention, there is provided a method of manufacturing an optical disc having a small diameter through hole in the central portion thereof, wherein the stamper is attached by suction in the step of attaching the opposite side of the transfer surface of the stamper to the die. Therefore, in addition to the effect of the third aspect, since the movement of the outer periphery can be restricted by the mold, it is possible to surely secure the fixing at the time of release by suction.

A disc according to claim 5 is formed on a disc-shaped disc body and on one surface of the disc body,
Since the recordable area of the information recording area where the information can be read out by reflecting the laser light is set to about 85% or more, data can be recorded up to the vicinity of the central portion, and The storage area can be increased, the storage area can be expanded with a single disk, and the storage capacity can be further increased by increasing the recording density. In particular, since the position of the lead-in is close to the center, the read / write speed response can be improved.

According to a sixth aspect of the present invention, a disc having no through hole at its center is formed on a disc-shaped disc body and a surface on one side of the disc body, and information is read out by reflecting a laser beam. In a disc having a possible information recording area, since the information recording area is set to about 85% or more, data can be recorded up to the vicinity of the central portion, and its storage area can be increased, The storage area can be expanded with a single disk, and the storage capacity can be further increased by increasing the recording density. In particular, since the position of the lead-in is close to the center, the read / write speed response can be improved.

A disk having a small-diameter through hole in the center thereof according to claim 7 is formed on a disk-shaped disk main body and one surface of the disk main body, and information is read out by reflecting laser light. In a disc having a possible information recording area, the information recording area is
Since it is set to about a percentage or more, data can be recorded up to near the central portion, its storage area can be increased, and the storage area can be expanded with a single disk,
Further, the storage capacity can be further increased by increasing the recording density. In particular, since the position of the lead-in is close to the center, the read / write speed response can be improved.

In addition to the effect of claim 5 or claim 6 or claim 7, the disk in claim 8 is an information storage area up to the central portion of the disk-shaped disk body. It can be effectively used up to the center.

[Brief description of drawings]

FIG. 1 is a structural diagram of a mold for explaining a method of manufacturing an optical disc having no through hole in a central portion according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a process of forming a disc by the die of FIG. 1 in a state where a movable die and a fixed die are opened.

FIG. 3 is an explanatory view showing a process of forming a disk by the mold of FIG. 1 in a state where a movable mold and a fixed mold are closed.

FIG. 4 is an explanatory diagram of an injection / cooling state showing a process of forming a disc by the mold of FIG. 1.

5 is an explanatory view showing a process of forming a disc by the die of FIG. 1 in a state where a movable die and a fixed die are opened after forming.

FIG. 6 is an explanatory view of a state of taking out an optical disc, which shows a process of forming a disc by the mold of FIG.

FIG. 7 is a plan view of an optical disc manufactured by a method of manufacturing an optical disc having no through hole at the center according to an embodiment of the present invention.

FIG. 8 is a plan view of an optical disc having a label according to an embodiment of the present invention.

FIG. 9 is a plan view of an optical disc manufactured by a conventional method for manufacturing an optical disc having no through hole in its center.

FIG. 10 is a perspective view showing a planar layout of the conventional video disc of FIG.

[Explanation of symbols]

 A movable type B fixed type 1 stamper 2 replica disc 3a movable side mirror surface 4b fixed side mirror surface 5 ejection port 6 stamper suction port 10 optical disk body 11 information recording area 20 label RI lead-in RO lead-out

Claims (8)

[Claims] 1. A step of mounting a stamper having data recorded on the transfer surface excluding the central portion on the opposite side of the transfer surface to one mold by a surface and restraining the outer periphery thereof, and an injection port for injecting a molding material. A step of clamping the other die having substantially the center position with the die to which the stamper is attached, and a molding material is injected from an injection port at the substantially center position of the die to form a disc-shaped disc. A method of manufacturing a disk having no through hole in its center, which comprises a step of molding. 2. The substantially central portion according to claim 1, wherein the stamper having data recorded on the transfer surface is attached by suction to the surface opposite to the transfer surface with respect to the mold. A method of manufacturing a disc having no holes. 3. A step of mounting the opposite side of the transfer surface of the stamper on which data is recorded on the transfer surface excluding the central portion to one mold by a surface, and the other having an injection port for injecting a molding material at a substantially central position. And a step of clamping the die with the die to which the stamper is attached, and a step of injecting a molding material from an injection port at a substantially central position of the die to form a disc. And a method of manufacturing a disk having a small-diameter through hole in the center. 4. The small diameter in the substantial center of claim 3, wherein the stamper having data recorded on the transfer surface is attached by suction to the surface opposite to the transfer surface with respect to the mold. A method of manufacturing a disk having a through hole. 5. A disc comprising a disc-shaped disc body and an information recording area formed on one surface of the disc body and capable of reading information by reflecting laser light, The information recording area is a disc having a recordable area of about 85% or more. 6. A disc comprising a disc-shaped disc body and an information recording area formed on one surface of the disc body and capable of reading information by reflecting a laser beam, The information recording area has a recordable area of about 85% or more. 7. A disc comprising a disc-shaped disc main body and an information recording area formed on one surface of the disc main body and capable of reading information by reflecting laser light, The information recording area is a disk having a small-diameter through hole in the center, characterized in that the recordable area is set to about 85% or more. 8. The information recording area according to claim 5, wherein the start position of the information recording is near the center of the disc, and the recordable area is set to about 85% or more. 8. A disk or a disk having no through hole in the central portion according to claim 6 or 7.
A disk having a small-diameter through hole in the center thereof.