JPH11328734A - Optical disk and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently manufacture optical disks, which record necessary and reproducible information, without having an excess inventory. SOLUTION: Two disk substrates 6 and 7 having at least information surfaces 6A and 7A, on which mutually different information recording signals are recorded on one surface, are pasted together so that the surfaces 6A and 7A are facing each other and optical disks are produced. A reflection layer 8 is formed on one of the information surfaces, which are to be reproduced, among the surfaces 6A and 7A of the two disk substrates 6 and 7. A label printed layer 13 is formed on the surfaces of the substrates 6 and 7, which have other information surfaces that are not to be reproduced, to prevent a reproducing. Thus, no unnecessary information is reproduced without conducting a new press and only necessary information is reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk and a method for manufacturing the same.

[0002]

2. Description of the Related Art Optical discs on which information is recorded or reproduced by using a laser beam are used in various industrial fields because of the large amount of information. Optical discs include a single-sided disc capable of reproducing from only one side, and a double-sided disc capable of reproducing from both sides. The structure of the double-sided disc allows playback from both sides of the disc, with different information on both sides. Structurally, two disc substrates each having an information pit on one side and a reflection film above the information pit are prepared, and the reflection films are bonded to each other with an adhesive. Some devices have a protective film between the adhesive and the reflective film to protect the reflective film.

By the way, if the information to be recorded is a series of long information, it is often cut into appropriate lengths and distributed in a size that is easy to handle, such as one volume, two volumes, three volumes, and easy to sell. General. As described above, so-called double-sided discs exist in which information signals are input to both sides and can be reproduced from both sides as described above. In particular, recently, as a high-density optical disk, a DVD (Digital
A disc called Versatile Disc has been developed and sold, and a double-sided disc also exists in this DVD. This double-sided disk can be made into a single disk by forming a disk base one by one and bonding them together. This type of optical disk has a large capacity such that information for one roll can be stored on one side, for example. In this type of disk, when an order for a single-sided disk is received, one disk forms a disk base 2 on which a necessary information signal 1 is recorded as shown in FIG. 11 and the other disk is called a dummy disk. A dummy disk substrate 3 containing no information to be written is formed, and both are bonded together with an adhesive layer 4 to form one optical disk. Reference numeral 5 denotes a label printing layer.

[0004]

By the way, for example, if the contents recorded on the disc are successive volumes such as one volume and two volumes, there are three patterns of purchasers. That is, if only the first volume is purchased and the contents are good, the second volume is purchased, the first and second volumes are purchased simultaneously, and the first and second volumes are both There is a pattern that a double-sided disc is desired because the disc-shaped one generally has a lower selling price. Due to the existence of these three purchasing classes, manufacturers must create three types of disks and prepare each type of disk. As a result, the number of unsold disks and the number of unsold disks increase. Furthermore, there was a major problem in production as described below.

[0005] That is, in general, the production of a disk is performed in such a form that a disk seller determines the number of ordered disks and places an order with a disk manufacturer. Initially,
When sales increase beyond the planned number and an additional order comes, the production maker looks for a master with the software of the additional order,
The disk will be produced by reshaping. Disk molding is performed using an injection molding machine. Disk molding is performed by mounting a master disk containing the relevant software in a disk molding die installed in one injection molding machine. And different information (software)
The disc containing is completed. When the number of orders for a piece of software is consumed, the master is removed from the mold, and then a master containing other software is attached. ing. As described above, a single molding machine and a mold are used to produce various types of discs by using a material containing different information as a master to be used.

[0006] The production efficiency of a disk depends on how to use the master for molding the disk for a long period of time without damaging it. The first reason for damaging the master is that the master is rejected when the master is attached to or detached from a disk molding die. Generally, a master is attached to a mold using a dedicated jig. However, when the master is attached, a scratch may be erroneously made and disk information on the master may be destroyed. This problem also occurs when the molding of the disc is completed. When the master is removed after the production of a predetermined amount is completed, the master is often made defective by detaching the master. Also, as a second point, as a thing that can be understood only by molding the disc after attaching the master, dust and the like are sandwiched between the mold and the master,
The master may be deformed and become a defective product. These scratches are found only after molding the disk, and the work of replacing the master with a new one occurs.In the worst case, the surface of the mold is damaged, and both the master and the mold are defective. It can be lost.

[0007] The molding staff produces discs while paying attention so as not to cause the above problems.
The problem becomes more serious as the production of various types and small quantities increases. In addition, a high-density optical disk called a DVD has a disadvantage that it is weakened against the above-mentioned scratches by an increase in the information density. Thus, the advantage of mass production is that the same software is mass-produced.In order to increase production efficiency, discs are produced in excess of the number ordered, and production is made in anticipation of additional orders from customers. , Somehow trying to take advantage of mass production. This inevitably increases the stock at the production plant, and consequently increases the cost of the disk. In recent years, when environmental issues have been raised, there has been a drawback that inefficient inventory management results in wasted resources.

The present invention focuses on the above problems,
The purpose of the present invention is to provide an optical disk and a method of manufacturing the same that can efficiently produce an optical disk on which necessary information that can be reproduced is recorded without having excessive inventory. To provide.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises two disk substrates each having at least one information surface on which a different information reproducing signal is engraved on one surface. In an optical disk bonded to face each other, a reflective layer is formed on one of the information surfaces of the two disk substrates to be reproduced, and the disk substrate has another non-reproduced information surface. Is formed with a layer for preventing reproduction.

Thus, if a layer for preventing reproduction, for example, a printing layer is provided on the surface of the disk substrate on which the information reproduction signal to be reproduced is formed, only the information reproduction signal of the other disk substrate is provided. It becomes playable. Therefore, if a surface on which a print layer is to be formed is selected as necessary, it is possible to reproduce only a desired signal from the two information reproduction signals. Therefore, unlike the conventional disk, a dummy disk base is not required, and the production efficiency can be improved. Furthermore, an optical disk capable of reproducing only a desired signal can be manufactured by merely changing the surface on which the layer for preventing reproduction is formed, for example, the surface on which the print layer is formed, so that it is not necessary to replace a mold or the like according to an order. A reflective layer or a recording layer may be formed in advance on the information surface of the disk substrate. Further, one of the disk substrates may be constituted by a disk substrate having a write-once or rewritable recording layer.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical disk according to the present invention and a method for manufacturing the same will be described below in detail with reference to the accompanying drawings. 1 and 2 are sectional views showing a first embodiment of the optical disk of the present invention, and FIG. 3 is a view showing a method for manufacturing the optical disk shown in FIGS. 1 and 2. 1 and 2, reference numeral 6 denotes a first disk base, 7 denotes a second disk base,
On one side, information surfaces 6A and 7A are engraved with different information reproduction signals (a software and b software). Both disk substrates 6, 7 are formed of, for example, a transparent polycarbonate resin. Usually, a large number of both disk substrates 6 and 7 are formed, and are stocked as they are without a reflective film.

Then, when an order or the like is required, the two disk substrates 6 and 7 are joined by bonding the information surfaces 6A and 7A to each other with an adhesive layer 12 therebetween. Prior to this joining, a reflective layer 8 made of, for example, a metal aluminum foil or the like is formed on the information surface side where reproduction is required according to an order. In the illustrated example, it is assumed that, for example, an order has been received for software a, and therefore the information surface 6A
The reflection layer 8 is formed thereon. Then, if the surface disk substrates 6 and 7 are bonded via the adhesive layer 12 as described above, the disk substrate on the opposite side on which the necessary information to be reproducible is recorded, here the second disk substrate 7 Label printing layer 1 with information on the disc printed on its surface
3 to prevent information reproduction from this surface. This label printing layer 13 is a layer for preventing reproduction. still,
In the case of this embodiment, since no reflective layer is formed on the information surface 7A, the recorded information on the information surface 7A cannot be reproduced without forming the printing layer 13.

In this embodiment, if an order is received for the software b, the reflection layer 9 is formed only on the information surface 7A as shown in FIG. The label print layer 14 may be formed on the surface of the disk substrate 6 as a layer for preventing reproduction. In FIG.
And the laser beam 16 indicate the irradiation direction of the laser beam during reproduction.
In the case of the first embodiment shown in FIGS. 1 to 3, the disk bases 6 and 7 were stocked without forming a reflective film as they were immediately after molding, but instead, a reflective layer and a protective film were formed. You may make it stock in a state. Further, for example, when chromium or aluminum alloy having good corrosion resistance is used as the reflection layer, it is possible to stock without applying a protective film. 4 and 5 are sectional views showing a second embodiment of the optical disk of the present invention, and FIG. 6 is a diagram showing a method for manufacturing the optical disk shown in FIGS. The same parts as those shown in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof will be omitted.

Here, as shown in FIG. 6, after forming the first and second disk bases 6 and 7, the respective information surfaces 6A and 7A are formed.
Reflective layers 8 and 9 and protective layers 10 and 11 made of, for example, a polycarbonate resin are sequentially formed thereon, and are stocked in this state. Then, for example, if an order for software a comes in accordance with the order, a label printing layer 13 is formed on the opposite side, that is, on the surface of the second disk base 7 as shown in FIG. Prevent regeneration. Also,
Conversely, when the order of the software b is received, a label print layer 14 is formed on the opposite side, that is, on the surface of the first disk substrate 6 as shown in FIG. .

As described above, the durability of the disk substrates 7 and 8 coated with the protective films 10 and 11 in air is improved. Therefore, the storage location of the disk substrates can be precisely controlled as in a clean room. Therefore, it is not necessary to store the data in the storage area, and the cost can be reduced. In addition, when a reflective layer and a protective layer are attached to the disk substrate, the cross-sectional structure of the optical disk is equivalent to the adhesive layer, protective layer, reflective layer, and disk substrate with the center of the disk thickness symmetrical. In addition, there is an advantage that the warpage of the disk is reduced.

FIG. 7 shows the state at this time, and it can be understood that the single-sided optical disk of the present invention has a smaller warp angle than the conventional single-sided optical disk. As described above, according to the present invention, the disk base corresponding to the software ordered and the other disks are pasted together, and the surface of the disk base containing the information other than the order is printed by labeling, which is conventionally required. It is possible to formulate a production plan without producing the dummy disk substrate. This allows individual disk substrates to be molded and stocked, and then bonded and shipped as needed without increasing the number of times the master is detached from the disk molding die, which makes the master defective. The number of times can be reduced, and an improvement in production efficiency is achieved.

Further, the reduction in the number of times the master is attached to and detached from the mold prevents an increase in the eccentricity of the formed disk base. This is because the master has a hole in the center for mounting the mold, and the coaxiality between the hole in the master and the signal spiral track on the master is important, and this coaxiality is the eccentricity of the disk. This is because it affects the components. When the number of times the master is detached from the mold is increased, the hole diameter of the inner diameter of the master is worn by the friction of attachment and detachment, and the disadvantage that the hole diameter increases is solved. Accordingly, the eccentricity of the disk base can be suppressed, and the eccentricity can be maintained favorably.

Furthermore, the disk bases formed individually are not limited to two types. For example, a soft and b soft of Company A,
If there is c-software of Company B, stock three types of disk substrates before bonding, a, b, and c-software,
According to the order number, ab software, ac software, etc. are combined in a combination, and a, b, and c software are printed according to the number of orders, and label printing is performed on the reproduction surface other than the necessary software. You will have the advantage of being able to fill orders. Also, if the a software and the b software are continuous, the sales are expected, and the label printing is performed on the b software so that only the a software can be reproduced. Label printing is performed near the innermost circumference of the disk as shown in Fig. 8, so that a mass-produced disk substrate can be made into three types of optical disks in the final stage, and cost reduction can be achieved while maintaining production efficiency. Becomes possible.

Further, in each of the above embodiments, the description has been made of the case where the disk substrate is a read-only disk substrate on both sides, but the disk substrate having a write-once or rewritable recording layer and the read-only disk substrate are combined. You may. FIG. 9 is a sectional view showing a third embodiment of the optical disk as described above, and FIG. 10 is a diagram for explaining a method of manufacturing the optical disk shown in FIG. As shown in FIG. 10, on the surface of the first disk substrate 6, the reflective layer 8 and the protective layer 10 are formed and stocked, and on the surface of the third disk substrate 20, the above-described write-once type or Rewritable recording layer 2
1. The reflective layer 22 and the protective layer 23 are sequentially formed and stocked. Then, when an order is received, the two substrates 6 and 20 are joined by the adhesive layer 12, and a label printing layer is formed on one of the surfaces where recording or reproduction is prevented. In FIG. 9, a label printing layer 14 is formed on the surface of the first disk substrate 6 in order to prevent signal reproduction, and the recording layer 21 of the other third disk substrate 20 is set in a usable state. I have.
Also in this case, it is a matter of course that the label printing layer is formed on the opposite side depending on the order.

As a specific production method, a molding machine is used to mold 1,000 pieces of 0.6 mm thick disk bases containing a soft, and then to form 0.1 mm thick b containing the soft.
A 1000 mm 6 mm disk substrate is molded, and then a 0.6 mm thick c
-Form 1000 RAM disk substrates. a soft and b soft form a reflective layer of aluminum after molding,
After that, a protective layer of UV curable resin is applied and cured,
Stock in the stocker. After molding, the c-RAM software forms a phase-change recording layer, similarly applies a protective layer of an ultraviolet curable resin, cures it, and stores it.

Now, in such a stock state,
400 pieces of software a, 400 pieces of software b, c-RAM
If the order of 200 pieces of software is received, the disc bases that have already been molded and stocked are combined and pasted together. For example, 500 double-sided boards of a-c software are created, and the label of a-soft Is printed 400 times. 500 double-sided boards of a-b software are prepared, and 100 labels of b-software are printed on the reproduction surface of the a-software. bc
Create 500 double-sided soft disks, c
Print 300 soft labels, c on the soft playback surface
A combination of double-sided discs 40 on which 200 labels of software are printed and the remaining labels are not printed
100 double-sided discs with 0 and ac software
Have the sheets ready for the next order. The label is printed on one side of the double-sided disc in accordance with a subsequent additional order and shipped.

In this case, the label printing is performed at the production factory. However, if it is sufficient to apply the label only, it is possible to apply the label at a place other than the disk production factory, for example, at the place of order. Also, by observing the sales of the disk, even when a double-sided disk of ab software is required, it is possible to promptly respond to the order. In this way, it is possible to respond to orders only by printing labels, and at the production site, without having to make a production plan in accordance with the number of orders from customers, the production site can make orders using its own production plan. It is possible to have digestible merit.

In the case of the disk in which the number of times of detachment of the master from the mold is reduced, the eccentricity of the disk is also suppressed, and the disk has a good cross-sectional structure close to a symmetrical system. Also has the effect of improving. In each of the above embodiments, a DVD has been described as an example of an optical disk, but it is needless to say that the present invention can be applied to other types of optical disks as described above.

[0024]

As described above, according to the optical disk of the present invention and the method of manufacturing the same, the following excellent effects can be obtained. A disc base on which different information reproducing signals are imprinted is bonded to form a printed layer on the surface of the disc base for unnecessary information, thereby preventing reproduction of the information, thereby enabling efficient disk production. It is possible to provide a high-quality disk at low cost without causing excessive inventory or defective products, and as a result, without generating a large amount of industrial waste. Also,
Since the number of times of attaching and detaching the mold can be reduced, the amount of eccentricity of the disk can be suppressed, and the chance of damage to the mold can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of an optical disk of the present invention.

FIG. 2 is a sectional view showing a first embodiment of the optical disk of the present invention.

FIG. 3 is a diagram showing a method of manufacturing the optical disc shown in FIGS. 1 and 2.

FIG. 4 is a sectional view showing a second embodiment of the optical disk of the present invention.

FIG. 5 is a sectional view showing a second embodiment of the optical disc of the present invention.

FIG. 6 is a diagram showing a method of manufacturing the optical disc shown in FIGS. 4 and 5;

FIG. 7 is a graph for comparing the warp angles of the conventional optical disk and the optical disk of the present invention.

FIG. 8 is a sectional view showing a modification of the second embodiment.

FIG. 9 is a sectional view showing a third embodiment of the optical disc.

FIG. 10 is a diagram illustrating a method of manufacturing the optical disc shown in FIG.

FIG. 11 is a sectional view showing an example of a conventional optical disk.

[Explanation of symbols]

6, 7, 20: disk base, 6A, 7A: information surface,
8, 9, 22 ... reflective layer, 10, 11, 23 ... protective layer, 1
2. Adhesive layer, 13, 14 Print layer (layer for preventing reproduction).

Claims (3)

[Claims] 1. An optical disc comprising at least two disc substrates having at least one information surface engraved with different information reproduction signals imprinted on one surface so that the information surfaces face each other. Forming a reflective layer on one of the information surfaces to be reproduced,
An optical disk, wherein a layer for preventing reproduction is formed on the surface of the disk substrate having the other information surface that is not reproduced. 2. A disk base having at least a recording layer formed on one side and a disk base having at least an information side engraved with an information reproducing signal on one side such that the recording layer and the information side face each other. An optical disc comprising a laminated optical disc, wherein a reflective layer is formed on the recording layer, and a layer for preventing recording or reproduction is formed on a surface of the disc base having the information surface. 3. A process for manufacturing two disk substrates having at least one information surface on which a different information reproduction signal is imprinted on one surface, and one of the information surfaces of the two disk substrates to be reproduced. Forming a reflective layer on the information surface, bonding the two disk substrates so that the information surfaces face each other, and preventing reproduction on the surface of the disk substrate having the other information surface that is not reproduced. Forming a layer for forming an optical disk.