JP2008077749A - Disk-shaped recording medium and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that since paper absorbs moisture or becomes dry to expand or contract and causes a difference in dimensions between a paper layer and another resin layer constituting a disk-shaped recording medium due to the expansion/contraction, the disk-shaped recording medium is warped, when the disk-shaped recording medium to which a paper layer is provided to a part of layer configuration such as a paper disk is stored or used for a long period of time. <P>SOLUTION: The disk-shaped recording medium has a performance equivalent to that of the conventional disk-shaped recording medium, wherein the resin layer of the conventional disk-shaped recording medium is made thin to reduce the amount of resin usage; a support layer is partially provided with a layer made, for example, of paper, and in addition, local rugged patterns are formed on a portion of the entire layer constituting the disk-shaped recording medium or a portion of the support layer by press working or the like in order to suppress warpage of the disk-shaped recording medium caused by variation in dimensions due to absorption of moisture or drying in the paper layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a disc-shaped recording which is an optical disc such as a record, a compact disc (CD), a hard disc digital versatile disc (HD-DVD), a Blu-ray disc (BD), or a digital versatile disc (DVD). The present invention relates to a medium and a manufacturing method thereof.

A disc-shaped recording medium generally includes a recording layer and a support layer that supports the recording layer. The recording layer is composed of a recording area in which recording is engraved and a non-recording area as a margin. The recording layer is engraved with fine irregularities (pits), and information can be extracted by reading this with light or a needle. In many cases, the surface of the recording layer is covered with a transparent protective layer in order to protect the recording layer.
One such disk-shaped medium is an optical disk. Here, a method for manufacturing an optical disk will be described. Polycarbonate and epoxy resin are formed by injection molding, etc., and the outer shape is the shape of an optical disk, thermoformed so that pits are formed on the surface, and a metal such as aluminum or silver is deposited or sputtered on the pits. To form a recording layer.
Next, the injection molded product having the recording layer formed thereon, and the injection molded product formed by the above method to support the recording layer, if necessary, or a polycarbonate on the protective layer to protect the recording layer Then, an optical disk is produced by bonding together injection molded products made of epoxy resin or the like.

For a conventional optical disk, a material having a small content of foreign matter and impurities, a high transmittance, and a low birefringence is selected so that stable reading or writing can be performed. Also, polycarbonate and epoxy resins that satisfy these conditions are required to have low water absorption, excellent heat resistance, high fluidity for molding processability, and excellent releasability so that the optical disk does not deform. Etc. are often used (see, for example, Patent Document 1).
However, due to recent environmental problems and depletion of petroleum resources, it has become necessary to reduce the amount of resin used in the optical disk.

However, when the resin layer of the optical disk is made thin, the rigidity of the optical disk itself is lost, and even if the optical disk is installed in the recording drive device, there is a problem that the recorded information on the optical disk cannot be read because the optical disk rotates eccentrically.

Therefore, as one method for reducing the amount of resin used in the optical disc, a paper disc using paper as a part of the support layer, so-called paper disc, has been proposed in order to maintain the rigidity of the disc. (Patent Document 2).
However, paper, which is the main constituent material of paper discs, has the characteristic that the dimensions fluctuate due to expansion and contraction due to moisture absorption or drying, and when paper discs are used or stored for a long period of time, the paper absorbs or dries moisture. Therefore, there is a problem that the paper disk is warped due to a difference in dimensions due to expansion and contraction with other resin layers constituting the paper disk.

JP 05-258349 A JP 2005-504774 A

  The present invention may be a disc-shaped recording medium with a reduced amount of resin, for example, or a disc-shaped recording medium in which a paper layer is provided on a part of a support layer such as a paper disc. The paper retains its shape, can be read and handled well, and the paper absorbs or dries moisture when a disc-shaped recording medium using a support that absorbs moisture like paper is stored or used for a long time. Therefore, a disk-shaped recording medium in which a difference in size due to expansion and contraction does not occur between the other resin layers constituting the disk-shaped recording medium and the disk-shaped recording medium does not warp, and a method for manufacturing the disk-shaped recording medium. The purpose is to provide.

Claim 1 is a disc-shaped recording medium comprising a recording layer covered with a protective layer and a support layer composed of a layer made of a resin or paper that supports the recording layer and the protective layer. The surface of the recording layer is composed of a recording area and a non-recording area at the periphery of the recording area, and the area that supports the non-recording area of a part or all of the layers constituting the support layer has local unevenness. It is another object of the present invention to provide the disc-shaped recording medium.
Claim 2 is a disc-shaped recording medium comprising a recording layer covered with a protective layer and a support layer composed of a layer made of a resin or paper that supports the recording layer and the protective layer. The recording layer surface is composed of a recording area and a non-recording area at the periphery of the recording area, and all the layers constituting the disc-shaped recording medium are areas corresponding to the non-recording area on one side of the disc-shaped recording medium. It is another object of the present invention to provide a disc-shaped recording medium having local irregularities that follow from one side to the other side.
3. A method for producing a disk-shaped recording medium according to claim 1, wherein a part of the support layer has local unevenness, and the local unevenness of the support layer is formed in an uneven shape. To provide a method for producing the disc-shaped recording medium by forming at least a recording layer and a protective layer on the support layer on which the uneven mold is formed.
A fourth aspect of the present invention is the method for manufacturing the disc-shaped recording medium according to the second aspect, wherein the local unevenness is uneven on the local unevenness of the disc-shaped recording medium. An object of the present invention is to provide a method for manufacturing the disc-shaped recording medium by forming a concavo-convex mold by pressing with a mold having a shape.
According to the present invention described above, the rigidity of the entire disk can be maintained even if the support layer is thin, and even if paper is used as a part of the support layer, due to the displacement of the layers constituting the disk due to expansion and contraction due to humidity. A disc-shaped recording medium capable of preventing disc warpage is provided.

The disc-shaped recording medium provided with the local uneven shape according to the present invention is flat without warping, and even when stored at high temperature and high humidity (80 ° C./85%) for 4 days, the disc-shaped recording medium is not displaced due to the expansion and contraction of the layer. Since the recording medium is not warped and the disk has rigidity, the disk-shaped recording medium capable of stably reading or writing information can be provided as the disk-shaped recording medium. .
As described above, the disc-shaped recording medium of the present invention can suppress the warpage of the disc-shaped recording medium and the eccentric rotation during use, and can reduce the amount of plastic material used compared to the conventional optical disc.

The disc-shaped recording medium of the present invention is formed by laminating a support layer, a recording layer, and a protective layer.

(Protective layer)
In order to prevent the reflective layer from being scratched and to serve as a lens for focusing the laser on the pit, the upper layer of the reflective layer is highly smooth, has good light transmission, and is relatively hard. For example, a protective layer is formed by bonding an adhesive, for example, to a polycarbonate or epoxy resin formed by injection.
The thickness of the protective layer is about 1.1 mm for CD, 0.5 mm for DVD, and 95 to 105 μm for Blu-ray disc.

(Recording layer)
The recording layer includes a recording holding layer that holds bits. The recording holding layer is preferably a resin material that can be processed by injection and can transfer pits, but any material can be used as long as it can transfer only pits. For example, a UV curable acrylic resin is laminated on a polypropylene substrate, The pits may be transferred with a stamper and cured by irradiation with UV. The recording holding layer 11 has a thickness of 10 to 30 μm.
In the case of a disc-shaped recording medium of the type that irradiates light and takes information in advance, a reflective film is formed on the recording holding layer by subjecting a metal or alloy to a dry film formation such as vapor deposition or sputtering. As the recording layer, when the recording layer is used to reproduce the recorded contents depending on the state of the light reflected by the laser beam, the recording layer is formed so that an opaque material such as a paper base material can be used as the recording holding layer. A recording layer corresponding to a blue laser having a short wavelength of laser light to be read and a short focus, for example, a Blu-ray disc is preferably used.
This recording layer is composed of a recording area in which recording is engraved and a non-recording area as its margin, and the non-recording area surrounds the recording area. It is not always necessary to form a pit or a reflective layer in the non-recording area.

(Support layer)
The support layer plays a role of supporting the recording layer, and may be configured by laminating a resin layer on the surface of the paper layer with an adhesive or the like, or it may be composed of only a thin resin layer.
Here, when the support layer is composed of paper and a resin layer, it is preferable that the paper layer is sandwiched between the resin layers from both sides.
When the support layer is composed only of a thin resin layer, the thickness of the resin layer is about 0.6 mm, and a polycarbonate film is preferably used from the viewpoint of strength.

(Resin layer)
The resin layer to be bonded to the surface of the paper layer is used for the purpose of eliminating irregularities on the surface of the paper. For example, as a plastic film, the film thickness is 50 to 200 μm, and the surface smoothness is the surface roughness (center of JISBO601-1982). A smooth film having a line average roughness Ra = 0.1 μm or less and a maximum height Rmax = 3.0 μm or less is preferably used.
There is no particular restriction on the material, but from the viewpoint of adhesion to the material forming the recording layer, a polycarbonate film is generally used, and the cost is low, so that polyolefin films such as polyethylene and polypropylene, polyethylene Polyester films such as terephthalate and polyamide films such as nylon are also used. Biodegradable plastics such as polylactic acid may be used.

(Paper layer)
The paper layer has a thickness of about 0.5 to 1 mm, and the material is not particularly limited as long as it is paper made of pulp. However, the paper layer is made of paper made from wood chips instead of pulp, non-wood materials such as kenaf. It may be manufactured paper. Further, in the case of paper, paper that is generally coated paper and pigment is coated is preferable, and paper that is calendered during paper making is more preferable. This is because the pigment is coated between the fibers on the paper surface and the paper becomes smooth by coating the pigment and carrying out the calendar process.
When it is not coated paper, it is necessary to devise a method for smoothing the unevenness of the paper surface by applying an adhesive when it is applied to the paper surface. As the paper that can be used as the base, paper mainly composed of natural fibers for papermaking can be used. In addition, this paper may be a mixture of synthetic fibers (for example, polyolefin fibers), and further, raw paper made from cotton pulp or purified wood pulp, using the swelling action of zinc chloride solution, After laminating to an arbitrary thickness, a rigid material such as vulcanized fiber obtained by removing zinc chloride and drying can be used.
In general, paper has front and back. This is because when paper is made, water swollen pulp is poured over a fine mesh, and when water is removed, a surface that contacts the mesh and a surface that does not contact the mesh are formed. It is.
The difference between the front and back of the paper may affect physical properties such as warpage. The surface that is in contact with the mesh and the surface that is not in contact with the mesh differ not only in the surface shape but also in the size and orientation of the pulp on the inner surface. Therefore, when cut in half in the thickness direction, the density, physical strength, and the like of the upper half are different. With this point in mind, a paper-laminated paper is preferably used. The balance between the front and back is improved, and paper with less warpage can be made.
Specifically, when two sheets of paper are pasted together, the back sides of the paper are pasted together to eliminate the front and back sides. Similarly, in the case of an even number of paper such as four layers, bonding is performed so that the front and back sides are symmetrical from the center of bonding. In addition, it is preferable to bond even numbered paper from the balance of the front and back, but when it is necessary to stack odd numbered paper for the purpose of adjusting the thickness of the recording medium, the paper that is in the center with less influence of warpage etc. It is preferable to laminate.
In addition, since paper is a material that expands and contracts due to water and changes its shape, a vapor deposition film or a metal foil may be attached from the viewpoint of water vapor barrier performance of the resin layer.

(adhesive)
An adhesive is used to bond the paper layer and the resin layer. The adhesive material may be a general adhesive, such as natural polymer resin, biodegradable resin, thermoplastic resin, thermosetting resin, moisture curable resin, photo curable resin, electron beam curable resin, etc. A material to which the film adheres may be used.
Also, if there is unevenness on the paper surface and the unevenness is not absorbed even after bonding the film, it is possible to fill the unevenness on the paper surface with an adhesive, and when using this method, adhesive coating Immediately after that, a solventless type adhesive that has a smooth coated surface but does not become uneven when the solvent volatilizes is preferable. The adhesive is also used for bonding the support layer and the recording layer. Since the recording layer only needs to be able to read and write the recording in the recording area, the recording layer can be bonded to both sides with the support layer as the center.

(Local unevenness)
By forming local irregularities on the disk-shaped recording medium, the rigidity of the entire disk can be maintained even if the support layer is thin, and even if paper is used as part of the support layer, the disk can be stretched due to humidity. It is possible to prevent the disk from warping due to the displacement between the layers constituting the disk.
Here, as the shape of the local unevenness, a jagged shape called a knurl shown in FIG. 2 (a) is preferably used. However, as shown in FIGS. 2 (b), (c), and (d), a partial or There is no problem as long as it is continuously crushed.
Further, the position where the local unevenness is formed is a non-recording area of a doughnut-shaped disk-shaped recording medium having an inner diameter of 15 mm and an outer diameter of 120 mm. For example, in the case of a Blu-ray disc, the area for setting the disc to the player (hereinafter referred to as a clamping area) having a diameter of 44 mm or less, or an outer peripheral portion having a diameter of 119 mm to 120 mm (hereinafter referred to as an outer periphery 25), or a CD. In a clamping area with a diameter of 46 mm or less, or an outer periphery with a diameter of 119 mm to 120 mm.

Although the local unevenness has an effect of reducing the warp of the disk-shaped recording medium in either the clamping area or the outer periphery, it is more preferable to form the local unevenness on both.
Further, the surface on which the local unevenness is formed may be either the surface F on which the recording layer 19 in FIG. 1 is formed or the surface G on which the recording layer 19 is not formed. However, for the purpose of reducing warpage, It is more effective to provide patterns on both sides F and G.
As a result of increasing the area where the local irregularities are formed for the purpose of reducing the warpage of the disk-shaped recording medium, the recording area 1 where pits are formed and the local irregularities are likely to interfere with each other, or the recording area 1 and the local area are localized. When there are few unevenness boundaries, it is preferable to provide local unevenness only on the surface G on which the recording layer 19 is not formed because the local unevenness does not affect the recording area 1.

Further, in the case where warpage occurs in the disk-shaped recording medium before forming the local unevenness, the warp can be more effectively reduced by changing the surface on which the local unevenness is formed depending on the direction of the warp. For example, when the recording surface F is warped upward with the recording surface F facing upward, local unevenness is formed on the recording surface F side, and when the recording surface 19 is not formed with the concave surface G, the recording layer 19 is formed. It is possible to more effectively reduce the warpage of the disk-shaped recording medium by forming local irregularities on the non-exposed surface G side.
Normally, when forming local irregularities in press processing, the mold is not heated, but at room temperature, but if the effect of local irregularities is to be more prominent, the mold may be heated. . In this case, it is preferable to perform the heating conditions at less than 100 ° C. This is because when the temperature is raised to 100 ° C. or higher, moisture in the paper becomes water vapor and publishes.

Further, as a result of intensive studies to solve the problem of warping of the disk-shaped recording medium, the present inventors have found irregularities in the inner and outer circumferences of the recording area so as to surround the recording area in the non-recording area. It has been found that the warpage of the disk-shaped recording medium is extremely small in the case where local unevenness is formed by applying a pressure of 0.1 MPa or more with the formed mold.

(About manufacturing method)
A method for producing the disc-shaped recording medium of the present invention will be described below.
The first method is a case where local irregularities are formed in all the layers constituting the disc-shaped recording medium, and the shape of the local irregularities in the non-recording area of the disc-shaped recording medium in which all the layers are laminated. This is a method for producing a disk-shaped recording medium by forming a locally uneven mold by pressing with a mold formed with (a first manufacturing method).
The other method is a case where local unevenness is formed on a part or all of the layers constituting the support layer. The unevenness is formed by pressing the local unevenness on the support layer with a mold having an uneven shape. In this method, a disk-shaped recording medium is manufactured by laminating at least a recording layer and a protective layer on a support layer on which an uneven mold is formed (second manufacturing method).

(First manufacturing method)
Next, there is a paper layer 15 in the support layer 18 of the disc-shaped recording medium shown in FIG. A first manufacturing method for a disc-shaped recording medium on which the unevenness 5 is formed will be described below.

First, regarding FIG. 7A, when the paper layer 15 is a paper sheet or a roll-shaped raw fabric, the shape of the local unevenness 5 as shown in FIG. The mold 21 is pressed at a pressure of 0.1 MPa or more to form local irregularities 5 on a paper sheet or a roll-shaped raw fabric as shown in FIG.

Next, an adhesive is applied and cured to such a thickness that the uneven portions of the local unevenness are sufficiently hidden on both sides of the paper sheet or the roll-shaped raw material on which the local unevenness 5 is formed.
Next, as shown in FIG. 7 (c), a second resin layer 13 made of polycarbonate, epoxy resin, or the like is bonded to either one of the paper sheet coated with the adhesive and the roll-shaped original fabric. .

7C, the recording holding layer 11 uses, for example, polycarbonate or an epoxy resin, and is formed by injection molding or the like, for example, of a disc-shaped recording medium as shown in FIG. Thermoformed into shape. Here, for example, a UV curable acrylic resin or the like may be laminated on the recording holding layer 11, pits may be transferred with a stamper, and UV irradiation may be performed.
Next, a reflective layer 9 is formed on either or both sides of the recording holding layer 11 by depositing a metal or alloy such as aluminum or silver ITO alloy by vapor deposition or sputtering.

The forming method 27 in FIG. 7 is the same as the steps from FIG. 6A to FIG. 6B of the first manufacturing method. That is, for example, polycarbonate or epoxy resin is used for the recording holding layer 11, and it is thermoformed into, for example, a donut shape having an inner diameter of 15 mm and an outer diameter of 120 mm as shown in FIG. A reflective layer 9 formed by depositing or sputtering a metal or alloy such as aluminum or silver ITO alloy on the surface is formed, and polycarbonate, epoxy resin or the like is formed on the reflective layer 9 in order to protect the reflective layer 9 The recording molded part 27 is formed by bonding the injection molded product made from the above as the protective layer 7 using an adhesive.

Next, the surface on which the second resin layer 13 is bonded to one surface of the paper sheet or the roll-shaped raw fabric and the surface on which the protective layer 7 of the recording component 27 is not bonded are bonded using an adhesive. to paste together.

In the step of FIG. 7D, the recording structure 27 is bonded to the doughnut shape having an inner diameter of 15 mm and an outer diameter of 120 mm, and disc-shaped recording as shown in FIG. The medium 200 is produced.

(Second manufacturing method)
The disc-shaped recording medium shown in FIG. 1 includes the non-recording area 3 of the recording layer 19 and is located above and below the non-recording area 3 in all layers 7 to 17 constituting the disc-shaped recording medium. Local unevenness 5 is formed by press working or the like. A manufacturing method for this disc-shaped recording medium will be described in detail below.

For example, polycarbonate or an epoxy resin is used for the recording holding layer 11 and is thermoformed into a donut shape having an inner diameter of 15 mm and an outer diameter of 120 mm as shown in FIG.
Here, for example, a UV curable acrylic resin or the like may be laminated on the upper layer of the recording holding layer 11, pits may be transferred thereon with a stamper, and cured by irradiation with UV to produce pits.

Next, a reflective layer 9 is formed on FIG. 6A by depositing a metal or alloy such as aluminum or silver ITO alloy by vapor deposition or sputtering. Here, the recording holding layer 11 and the reflective layer 9 are collectively referred to as a recording layer 19.
Further, in order to protect the reflective layer 9, an injection molded product made of polycarbonate, epoxy resin or the like is bonded as a protective layer 7 on the reflective layer 9 using an adhesive. This adhesive can also be used for laminating the support layer.
Here, the recording layer 19 and the protective layer 7 are collectively referred to as a recording configuration unit 27.

On the other hand, the support layer 18 shown in FIG. 6C is made of resin or paper, for example, composed of the first resin layer 17, the paper layer 15, and the second resin layer 13 as shown in FIG. The layer is composed of one or more layers. Here, it is preferable to have a resin layer on both sides of the paper layer in order to improve the smoothness because the paper layer is protected and the paper surface is rough and lacks smoothness.
Therefore, for example, an adhesive such as an acrylic UV curable resin is applied to the front and back surfaces of the paper, a film having a smooth surface such as a polycarbonate film is bonded, and the first resin layer 17, The second resin layer 13 is formed as the support layer 18.

Subsequently, as shown in FIG. 6C, the support layer 18 and the one in which the protective layer 7 is formed on the recording layer 19 are bonded with an adhesive or the like.

Further, using a punch, the die is cut into a donut shape having an inner diameter of 15 mm and an outer diameter of 120 mm as shown in FIG.

Next, in order to form the uneven shape, for example, the local unevenness shown in FIGS. 2A to 2D, in the non-recording area 3 in FIG. As shown in FIG. 5, a die cut into a donut shape having an inner diameter of 15 mm and an outer diameter of 120 mm is put into a mold 21 with local irregularities carved, and a pressure of 0.1 MPa or more is applied as shown in FIG. By forming the local irregularities 5, the disc-shaped recording medium 100 provided with the local irregularities 5 that follow from one surface to the other surface as shown in FIG. 6E is manufactured.

Here, the local unevenness 5 can be obtained by pressing the steps (c) to (d) of FIG. 6, that is, by bonding the recording layer 19 and the support layer 18 with an adhesive or the like without using the above-described press. When punching into a donut shape having an inner diameter of 15 mm and an outer diameter of 120 mm by punching, local irregularities shown in FIG. 6E are formed by forming local irregularities on the surface of the donut-shaped metal press. The pressing step can be omitted.

Further, the location where the local irregularities 5 are formed on the disc-shaped recording medium is the non-recording area 3 around the recording area where information is recorded. For example, in the case of a Blu-ray disc, Alternatively, the outer periphery has a diameter of 119 mm to 120 mm, and the CD has a clamping area with a diameter of 46 mm or less, or an outer periphery with a diameter of 119 mm to 120 mm.
Further, the local unevenness 5 has an effect of reducing the warp of the disc-shaped recording medium in either the clamping area or the outer periphery, but it is more preferable to form the local unevenness 5 on both.
As the press mold 21, it is possible to use one provided with unevenness corresponding to one surface, but in order to suppress the displacement due to expansion / contraction of the layer, a mold capable of engraving the same unevenness corresponding to both sides of the disk. 21 is preferably used to form local irregularities 5 on both sides of the disk.

Examples of the present invention are shown below.
(Example 1)

(Preparation of paper layer 15)
Paper was laminated to form the paper layer 15 constituting the support layer shown in FIG. Here, the lamination of the paper was performed by bonding four sheets of 0.2 mm thick coated paper by a hot press to produce a paper having a thickness of 0.8 mm. Here, the pressure was 0.5 MPa, the heating temperature was 90 ° C., the heating time was 1 minute, the cooling temperature was 20 ° C., and the cooling time was 2 minutes.

(Preparation of support layer 18)
Next, since the surface of the bonded paper layer 15 shown in FIG. 1 has a rough surface form, an acrylic UV curable resin is used on each side of the paper layer 15 with a wire bar for the purpose of obtaining surface smoothness. Coating to a thickness of 30 μm, laminating a 0.15 mm polycarbonate film (manufactured by Mitsubishi Engineering Plastics Co., Ltd., Iupilon FE-2000), irradiating with UV, the first resin layer 13 on the paper layer, The 2nd resin layer 17 was produced and the support layer 18 was obtained.

(Preparation of recording layer 19)
After the ultraviolet curable resin film punched into a donut shape (inner diameter 22 mm, outer diameter 120 mm) shown in FIG. 1 is bonded onto the recording holding layer 11 by pressure bonding with a rubber pad, the ultraviolet curable resin film is A stamper containing a ROM signal was pressure-bonded and cured by irradiating with ultraviolet rays to transfer the pits and projections. A reflective film 9 was formed thereon by sputtering a silver alloy having a thickness of 20 nm, and a recording layer 19 was obtained.

(Preparation of recording component 27)
Further, the recording component 27 was formed on the reflective film 9 as a protective layer 7 by pasting together a 80 μm thick polycarbonate film laminated with a 20 μm thick adhesive in advance (FIG. 6C). )). Here, 1-7 modulation was used as the modulation method of the ROM signal, the track chip was 0.32 μm, and the linear density was 11.7 nm / bit.

(Punching)
One side of the support layer 18 was coated with 20 μm of urethane-based adhesive, the surface opposite to the protective layer 7 of the recording component 27 was bonded, and punched out into a disk shape with a disk shape of 12 cm in diameter. (FIG. 6 (d)).

(Preparation of local unevenness 5)
Furthermore, the disc punched into the disc shape includes the non-recording area 5 of the recording layer 19 and the non-recording area 5 because the disc itself is warped due to curing shrinkage of the acrylic UV curable resin at the time of disc production. Rib forming mold using a press machine (HYP2000 manufactured by Nippon Automatic Machine Co., Ltd.) so that local irregularities 5 are formed in all layers 7 to 17 constituting the disc-shaped recording medium in the upper layer and the lower layer Then, local unevenness 5 was formed by pressing at a pressure of 0.1 MPa for 1 minute to form a disk-shaped recording medium 100 (FIG. 6E).
Here, in the rib forming region, a knurled rib having a pitch of 2 mm and a depth of 0.2 mm was formed on the outer periphery 25.

(Evaluation of disc-shaped recording media)
Next, the disk-shaped recording medium 100 manufactured by the above-described manufacturing method was subjected to an environmental test for 8 days in total, 4 days under the conditions of 80 ° C. and 85%, 1 day at 20% 80 ° C., and 3 days at 23 ° C. and 50%. As a result, the disc-shaped recording medium 100 is not warped, and when the disc-shaped recording medium 100 is reproduced using a drive device (DDU-1000 manufactured by Pulstec Industrial Co., Ltd.), stable reproduction is possible. there were.
(Example 2)

(Production of support layer 18)
As the paper layer 15 shown in FIG. 1, coated paper having a thickness of 0.8 mm is used, and moisture curable urethane resin is applied to both sides of the paper layer 15 with a roll coater at 120 ° C. to a thickness of 50 μm. As the first resin layer 17 and the second resin layer 13, a 0.1 mm polycarbonate film (manufactured by Mitsubishi Engineering Plastics Co., Ltd., Iupilon FE-2000) was bonded to form a support layer 18.

(Preparation of recording component 27)
In the recording layer 19 shown in FIG. 1, a 0.85 mm polycarbonate film (manufactured by Teijin Kasei Co., Ltd., cast film) is used for the recording holding layer 11, and an acrylic UV curable resin is applied on one surface. Then, it was pressed against a plate on which a mold corresponding to a Blu-ray pit was formed, irradiated with UV, and the pit was transferred and formed on the recording holding layer 11.
Further, a reflective layer 9 was formed by sputtering a silver alloy having a thickness of 20 nm on the surface where the pits of the recording holding layer were formed, and a recording layer 19 was produced.
Further, the recording component 27 was formed on the reflective film 9 as a protective layer 7 by laminating an adhesive having a thickness of 20 μm laminated in advance on a polycarbonate film having a thickness of 80 μm (FIG. 6B). )).
(laminate)

20 μm of urethane adhesive was applied to one surface of the support layer 18 and the surface opposite to the protective layer 7 of the recording component 27 was bonded (FIG. 6C).

(Punching)
The one having the recording structure 27 bonded thereto was punched into the shape of a Blu-ray disc (FIG. 6 (d)).

(Production of uneven shape 5)
Next, the material punched into the shape of the Blu-ray disc is put into a rib forming mold, the mold temperature is heated to 80 ° C., and pressing is performed at a pressure of 0.1 MPa for 1 minute for heating and 1 minute for cooling. Thus, a disk-shaped recording medium 100 was formed (FIG. 6E).
Here, the shape of the rib is a knurled rib as shown in FIG. The rib formation area is a non-recording area 3 of the disc-shaped recording medium 100, and ribs having a knurled pattern with a pitch of 2 mm and a depth of 0.1 mm are provided at positions having a diameter of 15 to 17 mm and a diameter of 119 to 120 mm. Formed.

(Evaluation of disc-shaped recording medium 100)
Next, the disk-shaped recording medium 100 manufactured by the above-described manufacturing method was subjected to an environmental test for 8 days in total, 4 days under the conditions of 80 ° C. and 85%, 1 day at 20% 80 ° C., and 3 days at 23 ° C. and 50%. As a result, the disc-shaped recording medium did not warp, and when the disc-shaped recording medium 100 was reproduced using a drive device (DDU-1000 manufactured by Pulstec Industrial Co., Ltd.), stable reproduction was possible. It was.
(Example 3)

  A disc-shaped recording medium was produced in the same manner as in Example 2 except that the local unevenness 5 was not formed.

(Evaluation of recording disk)
Immediately after the processing, the disc-shaped recording medium had relatively little warpage, and the recorded content of the disc-shaped recording medium could be read by a Blu-ray recorder device. When the disk-shaped recording medium was reproduced using a drive device (DDU-1000, manufactured by Pulstec Industrial Co., Ltd.), it was warped so that it could not be installed in the drive, and could not be reproduced.
Example 4

  On the outer periphery of a commercially available compact disc (CD) made of polycarbonate having a diameter of 118 mm or more, a conical potch having a diameter of 0.5 mm and a depth of 0.2 mm was formed at intervals of 1 mm. Here, the press working for forming the ribs was performed at 80 ° C. and 1 MPa.

(Evaluation of disc-shaped recording media)
When the CD produced under the above conditions was stored in an oven at 90 ° C. for 4 days, the CD did not warp, and the CD was regenerated using a drive device (DDU-1000 manufactured by Pulstec Industrial Co., Ltd.). As a result, stable reproduction was possible.
However, when a normal CD without ribs is stored in an oven at 90 ° C. for 4 days, the CD warps and is reproduced using a drive device (DDU-1000, manufactured by Pulstec Industrial Co., Ltd.). I was unable to play it.

The figure which shows the structure of the recording medium produced by the manufacturing method (1) by this invention The figure which shows the shape of the local unevenness | corrugation formed in the recording medium by this invention (enlarged view of the local unevenness | corrugation 5 of FIG. 1H) The figure which shows the structure of the recording medium produced by the manufacturing method (1) by this invention Sectional view of a disk-shaped recording medium according to the present invention The figure which shows the formation method of the local unevenness | corrugation by the press by this invention The figure which shows the manufacturing process of the disk-shaped recording field body by a 1st manufacturing method The figure which shows the manufacturing process of the disk-shaped recording field body by a 2nd manufacturing method

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Recording area 3 ... Non-recording area 5 ... Local unevenness | corrugation 7 ... Protective layer 9 ... Reflective layer 11 ... Recording holding layer 13 ... 2nd resin layer 15 ... Shape retaining layer 17 ... first resin layer 18 ... support layer 19 ... recording layer 21 ... mold 23 ... clamping area 25 ... outer periphery 27 ... recording component 100 ... disk-shaped recording medium 200 of manufacturing method 1 ... disk-shaped recording medium F of manufacturing method 2 ... recording surface G ... surface H on which no recording layer is formed ... cut-out portion of local unevenness 5

Claims (4)

In a disc-shaped recording medium comprising a recording layer covered with a protective layer and a support layer composed of a layer made of one or more resins or papers supporting the recording layer and the protective layer,
The recording layer surface is composed of a recording area and a non-recording area at the periphery of the recording area,
The disc-shaped recording medium according to claim 1, wherein an area corresponding to the non-recording area is provided with local irregularities in a part or all of the layers constituting the support layer. In a disc-shaped recording medium comprising a recording layer covered with a protective layer and a support layer composed of a layer made of one or more resins or papers supporting the recording layer and the protective layer,
The recording layer surface is composed of a recording area and a non-recording area at the periphery of the recording area,
All of the layers constituting the disk-shaped recording medium have local irregularities that follow from one surface of the disk-shaped recording medium to the other surface in an area corresponding to the non-recording area. recoding media. A method for producing a disk-shaped recording medium according to claim 1,
A part of or the whole of the layer constituting the support layer is pressed with a mold having a concavo-convex shape to form a local concavo-convex mold,
If necessary, the remaining layers constituting the support layer are laminated to form a support layer,
In the support layer on which the uneven mold is formed,
Furthermore, the manufacturing method of the disk-shaped recording medium including laminating | stacking a recording layer and a protective layer. A method for producing a disc-shaped recording medium according to claim 2,
Producing a disc-shaped recording medium comprising a recording layer covered with a protective layer and a support layer composed of one or more resins or paper layers supporting the recording layer and the protective layer,
A method for producing the disk-shaped recording medium, comprising forming a local unevenness by pressing with a mold having an uneven shape.