JP2006164429A - Optical disc manufacturing stamper, manufacturing method thereof, optical disc manufacturing roll stamper, and optical disc manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roll stamper for producing an optical disc capable of stably transferring a fine uneven pattern onto a radiation curable resin on a transfer material with high accuracy and stability, a stamper for producing an optical disc suitable for the roll stamper, and a method for producing the same. And an optical disc manufacturing method capable of obtaining a high-quality optical disc with high productivity.
By bringing a resin layer 52 made of a radiation curable resin provided on a stamper base 51 into contact with an optical disc master 60 and performing a step of curing this portion of the radiation curable resin at least once, When obtaining a resin stamper having one or more concavo-convex pattern portions to which the concavo-convex pattern 61 of the optical disc master 60 is transferred, the resin layer 52 and the optical disc master 60 are in contact with each other, or the resin layer 52 and the optical disc master 60 Is separated, the resin layer 52 around the portion in contact with the optical disc master 60 is smoothed.
[Selection] Figure 4

Description

  The present invention relates to an optical disk manufacturing stamper, a manufacturing method thereof, an optical disk manufacturing roll stamper, and an optical disk manufacturing method.

The recording layer of an optical disc is usually formed as follows.
First, a fine concavo-convex pattern composed of pits and / or tracks (land / groove) is formed on a glass plate by a photolithography method or the like to obtain a glass master. Based on this glass master, an optical disc master made of nickel or the like is produced by electroforming.
Next, the optical disc master or the optical disc master further duplicated by the electroforming method is set in a mold of an injection molding machine. A thermoplastic resin is injected into the mold to mold the optical disk substrate, and at the same time, the uneven pattern of the optical disk master is transferred to the surface of the optical disk substrate. In the case of a read-only optical disc, a light reflecting layer is formed on the concave / convex pattern surface of the optical disc substrate to form a recording layer. In the case of the write once type or the rewritable type, a light reflecting layer is formed on the concavo-convex pattern surface of the optical disk substrate, and further a colored film or an inorganic phase change material thin film layer made of an organic dye is formed as a recording layer.

The method of transferring the concave / convex pattern of the optical disk master to the surface of the optical disk substrate at the same time as injection molding of the optical disk substrate has a problem that productivity is low because only one optical disk substrate can be obtained by one injection. In addition, with the recent increase in the density of optical discs, the concavo-convex pattern has been further miniaturized, but with this method, the reproducibility of the concavo-convex pattern is becoming difficult.
Therefore, a roll stamper in which a plurality of stampers having a concavo-convex pattern are arranged at equal intervals on the peripheral surface of the roll body, and a resin layer made of an ultraviolet curable resin applied on a resin sheet to be an optical disk substrate. There has been proposed a method in which the concave / convex pattern of the stamper is transferred to a resin layer on a resin sheet (Patent Document 1).

However, in this roll stamper, a plurality of stampers are arranged at equal intervals on the peripheral surface of the roll body, so that a step is generated between the stamper and the roll body. For this reason, when the resin sheet passes through the roll stamper, a bulge due to the extra UV curable resin pushed out by the stamper is formed in the stepped portion.
By the way, the recording layer is not directly formed on the surface of the optical disk substrate as described above, but the sheet on which the recording layer is formed (hereinafter referred to as a recording layer sheet) and the optical disk substrate are separately manufactured and attached. Assuming matching, the base film of the recording layer sheet is considerably thin. When this base film is used instead of the resin sheet, when the base film to which the concavo-convex pattern has been transferred is wound up by the rising of the ultraviolet curable resin, the base film, and further the concavo-convex pattern, There is also a problem of deformation or damage.

There is known a method of directly forming an uneven pattern on a roll by an etching method or a mechanical engraving method used for making a gravure printing plate. Although this method does not cause a step on the roll surface, this method cannot form a fine uneven pattern having a track pitch or pit length of 1 μm or less, which is required for an optical disc.
Japanese Patent Laid-Open No. 11-345436

  Therefore, an object of the present invention is to provide an optical disc capable of transferring a fine uneven pattern to a radiation curable resin on a transfer object with high accuracy and stability without forming an excess of the radiation curable resin. An object of the present invention is to provide a manufacturing roll stamper, an optical disk manufacturing stamper suitable for the roll stamper, a manufacturing method thereof, and an optical disk manufacturing method capable of obtaining a high-quality optical disk with high productivity.

  The method for producing a stamper for producing an optical disk of the present invention comprises contacting a resin layer made of a radiation curable resin provided on a stamper base material with an optical disk master, and irradiating the resin layer at a portion in contact with the optical disk master. In the method of manufacturing a stamper for manufacturing an optical disc, the method includes a step of obtaining a resin stamper having one or more concavo-convex pattern portions to which the concavo-convex pattern of the optical disc master is transferred by performing the step of curing the radiation curable resin at least once. The resin layer around the portion in contact with the optical disc master is smoothed while the resin layer and the optical disc master are in contact with each other or after the resin layer and the optical disc master are separated.

The optical disc manufacturing stamper according to the present invention is a resin stamper having one or more concave and convex pattern portions to which the concave and convex pattern of the master optical disc is transferred, which is obtained by the method for manufacturing an optical disc manufacturing stamper according to the present invention. And
The optical disc manufacturing stamper according to the present invention is preferably a metal stamper having a concavo-convex pattern portion corresponding to the concavo-convex pattern portion of the resin stamper, which is duplicated based on the resin stamper.

The optical disc manufacturing roll stamper of the present invention comprises a roll main body and the optical disc manufacturing stamper of the present invention, and the optical disc manufacturing stamper is wound around the roll main body so as to cover the outer peripheral surface of the roll main body. It is characterized by that.
Here, it is desirable that the concave / convex pattern portion of the optical disc manufacturing stamper is 3 to 100 μm higher than the periphery thereof.

  The optical disk manufacturing method of the present invention includes a step of providing a layer made of a radiation curable resin on a base film, and the roll stamper and the base film on the base film while rotating the optical stamp manufacturing roll stamper of the present invention. The radiation curable resin is brought into contact, and with the roll stamper and the radiation curable resin in contact, the radiation curable resin is irradiated with radiation to cure the radiation curable resin, and the uneven pattern portion of the roll stamper is transferred. And a step of obtaining a recording layer sheet by providing at least a light reflection layer on the pattern sheet, and a step of bonding the recording layer sheet and the optical disc substrate.

According to the optical disk manufacturing stamper of the present invention, when this is wound around a roll body and used as a roll stamper, the radiation curable resin on the base film is formed without forming an excess of the radiation curable resin. A fine concavo-convex pattern can be transferred with high accuracy and stability.
Further, according to the method for manufacturing an optical disk manufacturing stamper of the present invention, the optical disk manufacturing stamper of the present invention can be easily manufactured.

In addition, according to the roll stamper for manufacturing an optical disk of the present invention, a fine uneven pattern can be stably and accurately transferred to the radiation curable resin on the base film without forming an excess of the radiation curable resin. can do.
According to the optical disk manufacturing method of the present invention using the optical disk manufacturing roll stamper of the present invention, a high-quality optical disk can be obtained with high productivity.

<Stamper>
FIG. 1 and FIG. 2 are diagrams showing an example of an optical disc manufacturing stamper (hereinafter also simply referred to as a stamper) according to the present invention.
The stamper 30 is a rectangular flat plate having substantially the same dimensions as the outer peripheral surface of a roll body, which will be described later, and has a plurality of concavo-convex pattern portions 31 on the surface of which concavo-convex patterns 32 corresponding to the concavo-convex patterns of the recording layer of the optical disc are formed. It is. In the present invention, the “concave / convex pattern” refers to a pit that is a small depression for recording information in a recording layer of an optical disc; a track (land / groove) composed of a concave portion (groove) and a convex portion (land); It means unevenness formed on the surface of the master or stamper, etc., in which the unevenness of the track is reversed. The “concave / convex pattern portion” means an area having the same shape as the optical disc in which the concave / convex pattern is formed.

  The stamper 30 includes a resin stamper having a plurality of concave / convex pattern portions to which the concave / convex pattern of the optical disc master is transferred; a metal stamper having a concave / convex pattern portion corresponding to the concave / convex pattern portions of the resin stamper, which is duplicated based on the resin stamper, etc. Is mentioned. Among these, it is more preferable to use a metal stamper as the stamper 30 because it is excellent in dimensional stability, wear resistance, and releasability.

The thickness of the metal stamper is preferably 50 to 500 μm, and more preferably 100 to 300 μm. When the thickness of the metal stamper is less than 50 μm, local dents are likely to occur when the metal stamper is wound around the roll body described later. When the thickness of the metal stamper exceeds 500 μm, the metal stamper is wound around the roll body. At this time, it becomes difficult to bend into a roll shape.
In addition, a thin film made of diamond-like carbon (DLC) may be formed on the surface of the metal stamper in order to improve wear resistance and releasability.

As shown in FIG. 2, the concavo-convex pattern portion 31 of the stamper 30 is preferably made 3 μm or more higher than its periphery. Here, the height h of the concavo-convex pattern portion 31 means the height from the surface around the concavo-convex pattern portion 31 to the deepest portion of the concave portion of the concavo-convex pattern 32 formed in the concavo-convex pattern portion 31.
By making the concavo-convex pattern portion 31 3 μm or more higher than its surroundings, as shown in FIG. 3, the concavo-convex pattern portion 31 is made of a resin layer 42 made of a radiation curable resin on a substrate film 41 that is a transfer target. When the concavo-convex pattern 43 is transferred, the concavo-convex pattern 43 is formed at the bottom of the recess 44 (depth h) corresponding to the height h of the concavo-convex pattern portion 31. Thereby, the uneven | corrugated pattern 43 is protected from the damage or deformation | transformation by contact.

  On the other hand, if the concavo-convex pattern portion 31 becomes too high, it is necessary to increase the film thickness of the resin layer 42 on the base film 41. Also, after the transfer of the concavo-convex pattern portion 31, the transfer portion film thickness and non-transfer Since the difference from the film thickness of the portion becomes too large, the height h of the uneven pattern portion 31 is preferably 100 μm or less. As for the height h of the uneven | corrugated pattern part 31, 3-30 micrometers is more preferable.

<Stamper manufacturing method>
An optical disk manufacturing stamper manufacturing method according to the present invention will be described by taking as an example the case where the stamper 30 is a metal stamper.
The stamper 30 is manufactured through a process of manufacturing a resin stamper (hereinafter referred to as a resin stamper manufacturing process) and a process of replicating a metal stamper based on the resin stamper (hereinafter referred to as a metal stamper manufacturing process). The

(Resin stamper manufacturing process)
As shown in FIG. 4, the surface (uneven pattern surface) of the optical disc master 60 on which the concave / convex pattern 61 is formed is pushed into the resin layer 52 made of radiation curable resin on the stamper base 51, and the outer diameter of the optical disc master 60 is A masking member 54 having a hole 53 of the same size as that of the stamper base 51 is disposed on the back surface of the stamper base 51, and the radiation curable resin is applied to the portion where the concave and convex pattern surface of the optical disc master 60 contacts from the back side of the stamper base 51. After irradiating the radiation and curing the radiation curable resin, the optical disc master 60 is separated from the resin layer 52, and the uneven pattern 61 of the optical disc master 60 is transferred to the resin layer 52 (transfer process).
After repeating this transfer process to form a desired number of uneven pattern portions 56, the entire resin layer 52 is irradiated with radiation to cure the entire resin layer 52, whereby the uneven pattern 61 of the optical disc master 60 is transferred. A resin stamper having a plurality of uneven pattern portions 56 is obtained.

In this transfer step, as shown in FIG. 4, the protrusion 55 due to the bulge caused by the excess radiation curable resin pushed out by being pushed into the resin layer 52 of the optical disc master 60 is a portion where the optical disc master 60 is in contact (uneven pattern). Part) around the surface of the resin layer 52. When the protrusion 55 is formed, a groove (not shown) corresponding to the protrusion 55 is formed around the concavo-convex pattern portion 31 of the metal stamper (stamper 30) replicated from the resin stamper. Then, as shown in FIG. 5, when the concave / convex pattern portion 31 of the metal stamper is transferred to the resin layer 42 made of a radiation curable resin on the base film 41 which is a transfer target, the protrusion 45 corresponding to the groove. Is formed on the surface of the resin layer 42. When such a protrusion 45 is present, when the pattern sheet 40 on which the uneven pattern 43 is formed is wound, the base film 41 and further the uneven pattern 43 are damaged or deformed by contact with the protrusion 45. .
Therefore, in the resin stamper manufacturing process, the resin layer around the portion where the optical disc master 60 is in contact with the resin layer 52 and the optical disc master 60 or after the resin layer 52 and the optical disc master 60 are separated. 52 smoothing is performed.

  As a smoothing method, (i) as shown in FIG. 6, after separating the resin layer 52 and the optical disc master 60 (or in a state where the resin layer 52 and the optical disc master 60 are in contact), the optical disc master A method of applying and smoothing a liquid radiation curable resin 57 on the surface of the resin layer 52 around the portion 60 (concave and convex portion 56) in contact with the surface; (ii) repeating the transfer step as shown in FIG. A liquid or semi-cured state formed on the surface of the resin layer 52 around the concavo-convex pattern portion 56 using a smoothing member 58 (a spatula, a doctor blade, a squeegee, etc.) after forming the desired number of concavo-convex pattern portions 56 (Iii) As shown in FIG. 8, using an optical disc master 64 having a concavo-convex pattern portion 63 having a height H projecting from the surface of a rectangular pedestal 62, a resin layer 52 and an optical disc Simultaneously contacting the master 64, a method for smoothing the periphery of the resin layer 52 surface of the irregularity pattern section 56 on the surface of the rectangular base 62; and the like.

  In the method (iii), when the concave / convex pattern of the optical disk master 64 is transferred to a portion adjacent to the portion where the surface of the rectangular pedestal 62 and the resin layer 52 are in contact, the surface of the rectangular pedestal 62 and the resin are already transferred. The resin layer 52 is so formed that the portion in contact with the layer 52 and the portion from which the surface of the rectangular pedestal 62 and the resin layer 52 are to come into contact with each other overlap with a width of 0.1 to 10 mm, preferably 1 to 5 mm. And the optical disc master 64 are preferably brought into contact with each other. Moreover, it is preferable not to sink the surface of the rectangular pedestal 62 into the resin layer 52.

  Examples of the stamper base material 51 include materials that transmit radiation, such as films, sheets, and plates made of resins such as acrylic resin, polycarbonate, polyester, and polyolefin. In addition, after transferring the concavo-convex pattern 61 of the optical disc master 60 or the optical disc master 64, the resin layer 52 is peeled off and the resin layer 52 is used as a resin stamper. For example, a glass plate or the like may be used. Here, “radiation” means light such as ultraviolet rays, visible light, infrared rays, and electron beams. The irradiation method is not limited to the radiation irradiation through the masking member as described above, and beam-shaped radiation may be scanned and irradiated to the region corresponding to the opening of the masking member.

The resin layer 52 is formed, for example, by laminating a liquid radiation curable resin on the stamper base 51 and a film made of a radiation curable resin in a semi-cured state on the stamper base 51. Layer, etc. The film thickness of the resin layer 52 may be thicker than the depth H at which an optical disk master 60 described later is pushed into the resin layer 52, and is, for example, 5 to 200 μm.
Examples of the radiation curable resin include an ultraviolet curable resin in which an oligomer or a monomer such as a urethane acrylate oligomer, a polyester acrylate oligomer, a low-viscosity acrylic monomer, and a photoinitiator are combined; a urethane-modified acrylate resin, an acrylic-modified polyester resin, or the like And an electron beam curable resin.
Examples of the coating method include gravure coating, micro gravure coating, die coating, comma coating, air knife coating, roll coating and the like.
The masking member 54 is a film, sheet, plate, or the like made of a material that does not transmit radiation and is provided with a hole 53 for transmitting radiation.

The optical disc master 60 and the optical disc master 64 are produced, for example, as follows.
A concavo-convex pattern composed of pits and / or tracks (land / groove) is formed on a glass plate by a photolithography method or the like to obtain a glass master. Based on this glass master, a metal disc made of nickel or the like is duplicated by electroforming, and this is used as an optical disc master.

The depth H at which the optical disc master 60 is pushed into the resin layer 52 is 3 to 100 μm so that the concave / convex pattern portion 31 of the metal stamper (stamper 30) replicated from the resin stamper is 3 to 100 μm higher than the surrounding area. It is preferable. Here, the depth H to be pushed in means the depth from the surface of the resin layer 52 to the deepest portion of the concave portion of the concave / convex pattern 61.
The height H of the concave / convex pattern portion 63 of the optical disc master 64 is 3 to 100 μm so that the concave / convex pattern portion 31 of the metal stamper (stamper 30) replicated from the resin stamper is 3 to 100 μm higher than the surrounding area. It is preferable that Here, the height H of the convex pattern portion 63 means the height from the surface of the rectangular pedestal 62 to the deepest portion of the concave portion of the concave / convex pattern 61.

(Metal stamper manufacturing process)
The metal stamper is manufactured by a replication method such as an electroforming method based on a resin stamper. The electroforming method uses electroplating technology, and deposits metal to the desired thickness by electrodeposition by electrolysis on the surface of the original (resin stamper). A method of precisely replicating the same thing.

  Specifically, a conductive layer made of a metal such as nickel is formed on the pattern surface of the resin stamper by sputtering, vacuum deposition or the like, and a metal such as nickel is electroformed to a desired thickness on the conductive layer. The metal stamper (stamper 30) having the concavo-convex pattern portion 31 corresponding to the concavo-convex pattern portion 56 of the resin stamper as shown in FIG.

  As metal materials used for electroforming, in addition to nickel, nickel alloy, nickel compound, copper, silver, gold, chromium, titanium, iron, zinc metal, alloys of these two or more, these Of these, compounds containing at least one of them can be mentioned. Among these, nickel and nickel-cobalt alloy are preferable in view of electroforming suitability and releasability.

(Other manufacturing methods)
When the resin stamper is the stamper 30, it has a concave / convex pattern obtained by inverting the concave / convex pattern of the optical disc master 60 (or the optical disc master 64), and the concave / convex pattern corresponds to the concave / convex pattern portion 31 of the stamper 30. The optical disc master formed in the above is prepared, and the same operation as the resin stamper manufacturing process may be performed.

<Roll stamper>
FIG. 9 and FIG. 10 are diagrams showing an example of a roll stamper for manufacturing an optical disc (hereinafter also simply referred to as a roll stamper) according to the present invention.
The roll stamper 10 includes a roll body 20 and a stamper 30 that is wound around the roll body 20 so as to cover the outer peripheral surface of the roll body 20, and both ends thereof are fixed to the folding fixing portions 21 of the roll body 20. It is roughly configured. In the present invention, “covering the outer peripheral surface of the roll main body” means that when there are fixing portions for fixing both ends of the stamper, the stamper is wound around the roll main body over the entire circumference of the roll main body excluding the fixing portion. Means the state.

(Roll body)
The roll body 20 is a cylindrical body or a columnar body, and a groove-like folding fixing portion 21 is provided on the outer peripheral surface thereof in parallel with the central axis of the roll body 20.
The roll body 20 may have a smooth outer peripheral surface, and the material thereof is not particularly limited. The outer diameter of the roll body 20 is preferably 50 mm or more. By setting the outer diameter to 50 mm or more, the stamper 30 is not cracked or cracked, and the flatness of the wound stamper 30 is ensured. The outer diameter of the roll body 20 is preferably 100 to 500 mm.

(Roll stamper manufacturing method)
A method for manufacturing the roll stamper 10 will be described by taking as an example the case where the stamper 30 is a metal stamper.
One end of the metal stamper (stamper 30) is fixed to the folding fixing portion 21 of the roll body 20, and the other end is pulled to apply tension to the metal stamper, and the metal stamper is wound around the roll body 20 so as to cover the outer peripheral surface. In a state where tension is applied to the stamper, the other end of the metal stamper is fixed to the folding fixing portion 21 of the roll body 20.

  The metal stamper is fixed to the folding fixing portion 21 of the roll body 20 by, for example, bending the end portion of the metal stamper, inserting the bent portion into the folding fixing portion 21, and placing a long metal plate on the folding portion. Then, the metal plate is folded and fixed to the fixing portion 21 for each bent portion of the metal stamper. Moreover, you may affix a metal stamper to the roll main body 20 using an adhesive agent, an adhesive, etc. However, in consideration of reuse of the roll body 20 and re-fixing, detachable fixing such as screwing is preferable.

<Optical disk>
FIG. 11 is a schematic cross-sectional view showing an example of an optical disk manufactured using the roll stamper 10. The optical disc 70 includes an optical disc substrate 71, a recording layer 72 bonded to one surface of the optical disc substrate 71 via an adhesive layer (not shown), and an adhesive layer (not shown) on the recording layer 72. The protective layer 73 and the protective layer 74 bonded to the other surface of the optical disk substrate 71 via an adhesive layer (not shown) are schematically configured.

(Optical disk substrate)
Examples of the material of the optical disk substrate 71 include resins such as polycarbonate, polyolefin, acrylic resin, and epoxy resin; biodegradable resins such as polylactic acid; paper whose surface is coated with resin.

(Recording layer)
The recording layer 72 is a layer in which information is recorded and / or a layer in which information can be recorded, and can record and / or read information by irradiating light.
The recording layer 72 includes a type in which information is recorded in advance when the optical disc is manufactured, and a type in which information can be recorded after manufacture. Usually, (1) information is recorded in advance when the optical disc is manufactured. Information that cannot be recorded later (reproduction-only type); (2) Information that cannot be recorded at the time of manufacturing the optical disc and information can be recorded after manufacture (recordable type); (3) The recorded information can be erased; The information can be classified into three types (rewriting type) that can record information again.
Hereinafter, each type of recording layer will be described in detail.

(Reproduction-only type)
FIG. 12 is a cross-sectional view showing an example of a read-only recording layer. The recording layer 72 includes a recording layer base material 81, an information pit formation layer 82 having irregularities on the surface formed on the surface of the recording layer base material 81, and a light reflection layer 83 covering the irregularities of the information pit formation layer 82. The recording layer base material 81 side is in contact with the optical disc substrate 71 (not shown), and the light reflection layer 83 side is in contact with the protective layer 73 via an adhesive layer (not shown).

  The recording layer substrate 81 serves as a support for the recording layer 72. As the recording layer substrate 81, a resin film is usually used. Examples of the resin film include a polycarbonate film, a polyethylene terephthalate film, a polyethylene film, and a cyclic polyolefin film.

  The information pit formation layer 82 has irregularities on the surface, and tracks and information pits are expressed by the irregularities. The information pit forming layer 82 is, for example, an ultraviolet curable resin in which an oligomer or a monomer such as a urethane acrylate oligomer, a polyester acrylate oligomer, or a low viscosity acrylic monomer and a photoinitiator is combined; a urethane-modified acrylate resin, an acrylic-modified polyester resin, or the like. An electron beam curable resin or the like is cured.

  The light reflecting layer 83 is provided along the unevenness of the information pit forming layer 82 and reflects the irradiated light. The light reflecting layer 83 is a thin film made of a metal such as aluminum, aluminum alloy, silver, or silver alloy formed by, for example, vacuum deposition or sputtering.

(Write-once type)
FIG. 13 is a cross-sectional view showing an example of a write-once recording layer. The recording layer 72 includes a recording layer base 91, an information track forming layer 92 having irregularities on the surface formed on the surface of the recording layer base 91, a light reflecting layer 93 covering the irregularities of the information track forming layer 92, The information pit recording layer 94 formed on the surface of the light reflecting layer 93 is roughly configured, the recording layer base material 91 side is in contact with the optical disc substrate 71 (not shown), and the information pit recording layer 94 side is adhesive. It is in contact with the protective layer 73 through a layer (not shown).

The recording layer base 91 is a support for the recording layer 72. As the recording layer base material 91, for example, the same resin film as the above-described recording layer base material 81 can be used.
The information track forming layer 92 has irregularities with a groove depth of 50 to 110 nm on the surface, and tracks are expressed by these irregularities. However, unlike the read-only type, no information pit is formed. The information track forming layer 92 is formed by curing an ultraviolet curable resin, an electron beam curable resin, or the like, for example, like the information pit forming layer 82 described above.
The light reflecting layer 93 is provided along the unevenness of the information track forming layer 92 and reflects the irradiated light. The light reflection layer 93 is a metal thin film formed by, for example, vacuum deposition, sputtering, or the like, similar to the light reflection layer 83 described above.

The information pit recording layer 94 is, for example, a colored film made of an organic dye or the like. By irradiating the information recording laser beam, the organic dye at the irradiated site changes in the molecular structure and is physically changed (destroyed). ), This portion becomes an information pit, and an information signal is recorded. Since the light transmittance is lowered at the site where the physical change has occurred, when the reading light is irradiated, the amount of light reflected from the light reflecting layer 93 is also reduced. As a result, the information signal is the same as when the concave and convex pits are formed. Can be detected.
Examples of organic dyes include phthalocyanine dyes, naphthalocyanine dyes, naphthoquinone dyes, and the like.

(Rewrite type)
FIG. 14 is a cross-sectional view showing an example of a rewritable recording layer. The recording layer 72 includes a recording layer substrate 101, an information track forming layer 102 having irregularities on the surface formed on the surface of the recording layer substrate 101, a light reflecting layer 103 covering the irregularities of the information track forming layer 102, The information pit recording layer 104 formed on the surface of the light reflecting layer 103 is roughly configured, the recording layer base material 101 side is in contact with the optical disk substrate 71 (not shown), and the information pit recording layer 104 side is adhesive. The protective layer 73 is in contact with each other through the layer.

The recording layer base material 101 serves as a support for the recording layer 72. As the recording layer substrate 101, for example, the same resin film as that of the recording layer substrate 81 described above can be used.
The information track forming layer 102 has irregularities with a groove depth of 50 to 110 nm on the surface, and tracks are expressed by these irregularities. However, unlike the read-only type, no information pit is formed. The information track forming layer 102 is formed by curing an ultraviolet curable resin, an electron beam curable resin, or the like, for example, like the information pit forming layer 82 described above.
The light reflecting layer 103 is provided along the unevenness of the information track forming layer 102 and reflects irradiated light. The light reflection layer 103 is, for example, a metal thin film formed by vacuum deposition, sputtering, or the like, similar to the light reflection layer 83 described above.

The information pit recording layer 104 is an inorganic phase change material thin film layer, for example, a transparent dielectric film including three layers of a SiO ₂ film, a GeSbTe film, and a SiO ₂ film. This is an information pit recording layer having a two-layer structure in which an SiO ₂ film 111, a GeSbTe film 112, an SiO ₂ film 113, a GeSbTe film 114, and an SiO ₂ film 115 are laminated in this order.

Information is recorded, erased and read by the information pit recording layer 104 as follows.
The laser light is focused on the GeSbTe film, the film is heated, and then rapidly cooled to polycrystallize or amorphize the GeSbTe film to record information. Then, a weak laser beam that does not affect the GeSbTe film is irradiated, light that is transmitted through the polycrystalline or non-crystallized GeSbTe film and reflected by the light reflecting layer is received, and information is obtained depending on whether the GeSbTe film is crystallized. Is read. On the other hand, the GeSbTe film is crystallized and erased by condensing a lower intensity laser beam on the polycrystalline or non-crystallized GeSbTe film and slowly heating it. This recording / erasing is reversible, and another information can be recorded again after erasing the recording.

Possible instead of SiO ₂ film, ZnS-SiO ₂ film, Ta ₂ O ₅ film, SiN film, also possible to use an AlN film. Further, an AgInSbTe film can be used instead of the GeSbTe film.
Each of these films can be formed by sputtering, vacuum deposition, or the like.
The thickness of each film is approximately 10 to 300 nm, and may be appropriately set depending on the type and number of layers. For example, the thickness of each film of the information pit recording layer 104 is SiO ₂ film (220 nm) / GeSbTe film (13 nm) / SiO ₂ film (25 nm) / GeSbTe film (40 nm) / SiO ₂ film (95 nm).

(Protective layer)
The protective layer 73 protects the surface of the recording layer 72 and prevents the recording layer 72 from being damaged.
As the protective layer 73, a resin film having high light transmittance is preferable because it is necessary to transmit the light applied to the optical disk to the recording layer 72.
The thickness of the protective layers 73 and 74 is 0.03-1.0 mm normally, Preferably it is 0.1-0.6 mm.

<Optical disk manufacturing method>
Hereinafter, a method for manufacturing the optical disc 70 using the roll stamper 10 will be described.
The optical disk 70 includes, for example, a step of providing the resin layer 42 on the base film 41 (resin layer forming step), and an uneven pattern portion 31 of the stamper 30 wound around the roll stamper 10. 42 to obtain a pattern sheet (pattern sheet manufacturing process) obtained by transferring the pattern to the concavo-convex pattern portion 31, and a process for obtaining a recording layer sheet by providing a light reflecting layer or the like on the pattern sheet (recording layer sheet manufacturing process) ) And a step of bonding the recording layer sheet and the optical disc substrate 71 (bonding step).

(Resin layer forming process)
A liquid radiation curable resin is applied to a belt-like base film 41 that moves in a certain direction to provide a resin layer 42. Alternatively, the resin layer 42 is provided on the base film 41 by laminating a belt-like base film 41 moving in a certain direction and a film made of a semi-cured radiation curable resin.
The base film 41 serves as the recording layer bases 81, 91, 101 of the recording layer 72 of the optical disc 70. Examples of the base film 41 include a polycarbonate film, a polyethylene terephthalate film, a polyethylene film, and a cyclic polyolefin film. A resin film such as is used.

The resin layer 42 becomes the information pit formation layer 82 and the information track formation layers 92 and 102 of the recording layer 72 of the optical disc 70. The radiation curable resin of the resin layer 42 includes a urethane acrylate oligomer, a polyester acrylate oligomer, An ultraviolet curable resin in which an oligomer or monomer such as a low-viscosity acrylic monomer and a photoinitiator are combined; an electron beam curable resin such as a urethane-modified acrylate resin or an acrylic-modified polyester resin is used. The film thickness of the resin layer 42 should just be thicker than the height h of the uneven | corrugated pattern part 31 of the stamper 30, for example, is 5-200 micrometers.
Examples of the coating method include gravure coating, micro gravure coating, die coating, comma coating, air knife coating, roll coating and the like.

(Pattern sheet manufacturing process)
As shown in FIG. 15, while rotating the roll stamper 10, the resin layer 42 side of the base film 41 is pressed against the roll stamper 10 by the pressing roll 121, and the radiation is released in a state where the roll stamper 10 and the resin layer 42 are in contact with each other. By irradiating the resin layer 42 with radiation from the lamp 122 from the base film 41 side to cure the radiation curable resin and separating the roll stamper 10 and the resin layer 42, as shown in FIG. A pattern sheet 40 to which the uneven pattern portion 31 of the stamper 30 wound around the roll stamper 10 is transferred is obtained.
Examples of the radiation lamp 122 include an ultraviolet lamp such as a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, and a magnetron lamp; and a fermentor type electron beam chamber.

(Recording layer sheet manufacturing process)
A recording layer sheet is obtained by providing at least a light reflection layer on the resin layer 42 of the pattern sheet 40. The recording layer sheet is manufactured differently for a read-only type, a write-once type, and a rewritable type.
Hereinafter, a method for producing each type of recording layer sheet will be specifically described.

(Reproduction-only type)
On the resin layer 42 (corresponding to the information pit forming layer 82) of the pattern sheet 40, a light reflecting layer 83 made of a metal thin film is formed by vacuum deposition, sputtering or the like, and a read-only recording layer sheet is obtained.

(Write-once type)
The light reflecting layer 93 is formed in the same manner as the read-only light reflecting layer 83.
Next, an organic dye is applied on the light reflecting layer 93 to form an information pit recording layer 94 made of a colored film of the organic dye. Examples of the coating method include gravure coating, micro gravure coating, die coating, comma coating, air knife coating, roll coating and the like.

(Rewrite type)
The light reflecting layer 103 is formed in the same manner as the write-once type.
Next, a SiO ₂ film 111, a GeSbTe film 112, a SiO ₂ film 113, a GeSbTe film 114, and a SiO ₂ film 115 are sequentially formed on the light reflecting layer 103 by sputtering, vacuum deposition, or the like.

(Bonding process)
The recording layer sheet and the optical disk substrate are bonded to each other by (i) providing a protective layer 73 on the band-shaped recording layer sheet, and then punching the uneven pattern portion of the recording layer sheet into a disk shape. And a disk-like optical disk substrate 71 having a protective layer 74 provided on the back surface thereof, with an adhesive or the like; (ii) a protective layer 73 is provided on the belt-like recording layer sheet, and the belt-like recording layer A method in which a sheet and a strip-shaped optical disk substrate 71 provided with a protective layer 74 on the back surface are bonded together with an adhesive or the like, and then a laminated sheet of the recording layer sheet and the optical disk substrate 71 is punched into a disk shape; Done.

<Action>
In the resin stamper described above, the resin layer around the portion with which the optical disc master 60 contacts is smoothed during the manufacture thereof, so that the projection 55 as shown in FIG. 4 is not formed. Therefore, when the concavo-convex pattern portion 31 of the metal stamper (stamper 30) replicated based on this resin stamper is transferred to the resin layer 42 on the base film 41 as a transfer target, as shown in FIG. When the pattern sheet 40 is wound up, the base film 41 and the concavo-convex pattern 43 are not damaged or deformed when the pattern sheet 40 is wound up. Therefore, a fine concavo-convex pattern can be transferred to the radiation curable resin on the base film 41 with high accuracy and stability.

  Further, in the roll stamper 10 described above, the stamper 30 is wound around the roll body 20 so as to cover the outer peripheral surface of the roll body 20, so that there is no step between the roll body 20 and the stamper 30. . Therefore, when the base film 41 provided with the resin layer 42 passes through the roll stamper 10, there is no bulge due to the excess radiation curable resin extruded by the stamper 30, and the uneven pattern portion of the stamper 30. When the pattern sheet 40 to which the 31 has been transferred is wound, the base film 41 and the uneven pattern 43 of the resin layer 42 are not deformed or damaged by the rising. Therefore, a fine concavo-convex pattern can be transferred to the radiation curable resin on the base film 41 with high accuracy and stability.

  Further, when the concave / convex pattern portion 31 of the stamper 30 is 3-100 μm higher than the periphery thereof, when the concave / convex pattern portion 31 is transferred to the resin layer 42 of the base film 41, the concave / convex pattern 43 is changed to the concave / convex pattern portion 31. It is formed at the bottom of the recess 44 corresponding to the height of. Thereby, the uneven | corrugated pattern 43 is protected from the damage or deformation | transformation by contact.

  Further, by manufacturing the optical disc 70 using such a roll stamper 10, the uneven pattern portion 31 of the stamper 30 can be efficiently transferred to the resin layer 42 of the base film 41, and the pattern sheet 40, When the recording layer sheet is manufactured, the concave / convex pattern 43 of the resin layer 42 is not deformed or damaged, so that a high-quality optical disc can be obtained with high productivity.

The roll stamper of the present invention is not limited to the roll stamper 10 shown in FIG. 9, and any stamper 30 may be used as long as the stamper 30 is wound around the entire circumference of the roll body 20. For example, as shown in FIG. 16, a roll in which the width of the stamper 33 is shorter than the length in the central axis direction of the roll body 20 and the outer peripheral surface of the roll body 20 is exposed outside both edges of the stamper 33. The stamper 11 may be used.
Further, the stamper is not limited to the stamper 30 in the illustrated example. For example, the number of the uneven pattern portions formed on the stamper may be one. However, from the viewpoint of the productivity of the optical disk, it is preferable that there are a plurality of uneven pattern portions formed on the stamper.

Examples of the present invention are shown below.
[Example 1]
(Manufacture of resin stampers)
A disc made of nickel by electroforming from a glass master having an outer diameter of 120 mm, on which a reproduction-only concavo-convex pattern (track pitch 0.32 μm, minimum pit length 0.138 μm) consisting of tracks (lands / grooves) and pits is formed. An optical disc master was prepared.
A liquid UV curable resin (Shin-Nakamura Chemical Co., Ltd., U-201HA) is 10 μm thick on an acrylic plate (Mitsubishi Rayon Co., Ltd., Acrylite EX) having a width of 300 mm, a length of 600 mm, and a thickness of 1 mm. The resin layer was provided by coating. The concave / convex pattern surface of the optical disc master is pushed into the resin layer, and a masking member provided with a hole having the same size as the outer diameter of the optical disc master is disposed on the back surface of the acrylic plate, and the concave / convex pattern of the optical disc master is provided from the back side of the acrylic plate. The UV curable resin at the surface contacted portion was irradiated with UV rays (80 W / cm) to cure the radiation curable resin, and then the optical disc master was separated from the resin layer, and the concave / convex pattern of the optical disc master was transferred to the resin layer. .

  After repeating this operation to form eight concavo-convex pattern portions, the surface of the resin layer around the concavo-convex pattern portion is smoothed using a squeegee, and finally, the entire surface is irradiated with ultraviolet rays to thereby form the eight concavo-convex pattern portions. A resin stamper having was produced. The roundness of the transferred concavo-convex pattern portion is within ± 5 μm, and when the concavo-convex pattern is measured with AFM (manufactured by SII, atomic force microscope), the same tracks and pits as the optical disc master are reproduced. confirmed. The depth from the surface of the resin layer to the top of the convex portion of the concave / convex pattern was 12 μm, and the height of the protrusion formed around the concave / convex pattern portion was 1 μm or less.

(Manufacture of metal stampers)
Nickel is deposited on the pattern surface of the resin stamper by vacuum deposition to form a conductive layer made of 0.1 μm nickel, and nickel is deposited thereon by electroforming to form an uneven pattern on the resin stamper. A metal stamper with a thickness of 180 μm having a concavo-convex pattern portion corresponding to the portion was duplicated. When the concavo-convex pattern of the metal stamper was measured by AFM, it was confirmed that the same tracks and pits as the original optical disc were reproduced. Further, the height h of the uneven pattern portion was 12 μm.
(Manufacture of roll stampers)
The obtained metal stamper is wound around an iron roll with an outer diameter of 150 mm so that the outer peripheral surface of the roll is covered with the concavo-convex pattern facing outward, and both ends are screwed to the roll groove (folding fixing part). And a roll stamper was obtained.

(Manufacture of recording layer sheet)
Using a die coater to a strip-shaped polyethylene terephthalate (PET) film (Teijin DuPont, Purex HPE) having a width of 350 mm and a thickness of 75 μm that moves in a certain direction, a liquid UV curable resin (Henkel, Loctite 349) ) Was applied to a thickness of 10 μm to provide a resin layer.
A roll stamper is attached to the stamper device shown in FIG. 15, and while rotating the roll stamper, the resin layer side of the PET film is pressed against the roll stamper with a pressing roll, and the metal halide lamp is in contact with the roll stamper and the resin layer. The pattern sheet on which the concavo-convex pattern portion of the metal stamper was transferred was obtained by irradiating the resin layer from the PET film side to cure the ultraviolet curable resin and then separating the roll stamper and the resin layer. Obtained. On the resin layer of this pattern sheet, aluminum was vapor-deposited by a vacuum vapor deposition method to form a light reflecting layer having a thickness of 60 nm to obtain a read-only recording layer sheet. The roundness of the transferred concavo-convex pattern portion was within ± 5 μm, and when the concavo-convex pattern was measured by AFM, it was confirmed that the same tracks and pits as the original optical disc were reproduced. The depth h of the concavo-convex pattern portion was 12 μm, and the height of the protrusion formed around the concavo-convex pattern portion was 1 μm or less.

(Production of optical disc)
On the light reflecting layer of the recording layer sheet, as a protective layer, a polycarbonate film having a thickness of 20 μm laminated in advance on a polycarbonate film having a thickness of 80 μm was bonded, and then the concave / convex pattern portion of the recording layer film was formed into a disk shape. The PET film surface of this disk-shaped recording layer sheet was punched and attached to a disk-shaped optical disk substrate made of polycarbonate and having a thickness of 1.0 mm to obtain an optical disk. When the information recorded on the optical disk was read using an optical disk drive (product name: DDU-1000) manufactured by Pulstec Industrial Co., Ltd., it could be read without any problem.

[Example 2]
(Manufacture of resin stampers)
Using a glass master having an outer diameter of 120 mm, the same as in Example 1, and having an uneven pattern portion (height H = 3 μm) protruding from the surface of a rectangular pedestal 140 mm × 140 mm × thickness 1 mm by electroforming An optical disc master was prepared.
A liquid UV curable resin (Shin-Nakamura Chemical Co., Ltd., U-201HA) is 10 μm thick on an acrylic plate (Mitsubishi Rayon Co., Ltd., Acrylite EX) having a width of 300 mm, a length of 600 mm, and a thickness of 1 mm. The resin layer was provided by coating. The concave / convex pattern surface of the optical disc master is pushed into the resin layer, and a masking member provided with a hole having the same size as the outer diameter of the optical disc master is disposed on the back surface of the acrylic plate, and the concave / convex pattern of the optical disc master is provided from the back side of the acrylic plate. The UV curable resin at the surface contacted portion was irradiated with UV rays (80 W / cm) to cure the radiation curable resin, and then the optical disc master was separated from the resin layer, and the concave / convex pattern of the optical disc master was transferred to the resin layer. .

  This operation was repeated to form eight uneven pattern portions. At this time, when transferring the concave / convex pattern of the optical disk master to a portion adjacent to the portion where the surface of the rectangular pedestal and the resin layer are in contact with each other, the portion where the surface of the rectangular pedestal and the resin layer are already in contact, The surface of the rectangular pedestal and the portion where the resin layer is to contact are overlapped with each other with a width of 5 mm. Finally, the entire surface was irradiated with ultraviolet rays to produce a resin stamper having eight uneven pattern portions. The roundness of the transferred concavo-convex pattern portion was within ± 5 μm, and when the concavo-convex pattern was measured by AFM, it was confirmed that the same tracks and pits as the original optical disc were reproduced. Further, the depth from the surface of the resin layer to the top of the convex portion of the concave / convex pattern was 3 μm, and the height of the protrusion formed around the concave / convex pattern portion was 1 μm or less.

(Manufacture of metal stampers)
A metal stamper was duplicated in the same manner as in Example 1 based on the obtained resin stamper. When the concavo-convex pattern of the metal stamper was measured by AFM, it was confirmed that the same tracks and pits as the original optical disc were reproduced. Further, the height h of the uneven pattern portion was 3 μm.
(Manufacture of roll stampers)
A roll stamper was obtained in the same manner as in Example 1 by using the obtained metal stamper.

(Manufacture of recording layer sheet)
Using the obtained roll stamper, a read-only recording layer sheet was obtained in the same manner as in Example 1. The roundness of the transferred concavo-convex pattern portion was within ± 5 μm, and when the concavo-convex pattern was measured by AFM, it was confirmed that the same tracks and pits as the original optical disc were reproduced. The depth h of the concavo-convex pattern portion was 3 μm, and the height of the protrusion formed around the concavo-convex pattern portion was 1 μm or less.
(Production of optical disc)
An optical disk was obtained in the same manner as in Example 1 using the obtained recording layer sheet. When the information recorded on the optical disk was read using an optical disk drive (product name: DDU-1000) manufactured by Pulstec Industrial Co., Ltd., it could be read without any problem.

  By using the optical disk manufacturing stamper of the present invention, a high-quality optical disk can be obtained with high productivity.

It is a schematic top view which shows an example of the stamper for optical disk manufacture of this invention. It is a schematic sectional drawing which shows the uneven | corrugated pattern part of the stamper of FIG. It is a schematic sectional drawing which shows the transferred uneven | corrugated pattern formed in a to-be-transferred object by the stamper of FIG. It is a schematic sectional drawing which shows a mode that the uneven | corrugated pattern of an optical disk original disk is transcribe | transferred and a resin stamper is manufactured. FIG. 5 is a schematic cross-sectional view showing a transferred concavo-convex pattern formed on a transfer object by a stamper replicated based on the resin stamper of FIG. 4. It is a schematic sectional drawing which shows the resin stamper by which the resin layer surface around the uneven | corrugated pattern part was smooth | blunted. It is a schematic perspective view which shows a mode that the resin layer surface around the uneven | corrugated pattern part of a resin stamper is smoothed. It is a schematic sectional drawing which shows a mode that the uneven | corrugated pattern of an optical disk original disk is transcribe | transferred and a resin stamper is manufactured. It is a schematic perspective view which shows an example of the roll stamper for optical disk manufacture of this invention. FIG. 2 is a schematic end view of the optical disk manufacturing roll stamper of FIG. 1. It is a schematic sectional drawing which shows an example of an optical disk. It is a schematic sectional drawing which shows an example of the recording layer of an optical disk. It is a schematic sectional drawing which shows the other example of the recording layer of an optical disk. It is a schematic sectional drawing which shows the other example of the recording layer of an optical disk. It is the schematic which shows an example of the stamper apparatus using the roll stamper for optical disk manufacture of this invention. It is a schematic perspective view which shows the other example of the roll stamper for optical disk manufacture of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Roll stamper 11 Roll stamper 20 Roll main body 30 Stamper 31 Uneven pattern part 32 Uneven pattern 33 Stamper 40 Pattern sheet 41 Base film 42 Resin layer 51 Stamper base material 52 Resin layer 56 Uneven pattern part 60 Optical disk master 61 Uneven pattern 64 Optical disk master 70 Optical disc 71 Optical disc substrate 72 Recording layer 83 Light reflecting layer 93 Light reflecting layer 103 Light reflecting layer

Claims (6)

One step of bringing a resin layer made of a radiation curable resin provided on a stamper base material into contact with an optical disc master, and irradiating the resin layer in a portion in contact with the optical disc master to cure the radiation curable resin. In the manufacturing method of a stamper for manufacturing an optical disk, including the step of obtaining a resin stamper having one or more uneven pattern portions to which the uneven pattern of the optical disk master is transferred by performing the above,
An optical disc manufacturing stamper characterized by smoothing a resin layer around a portion in contact with an optical disc master in a state where the resin layer and the optical disc master are in contact with each other or after the resin layer and the optical disc master are separated. Production method.   A stamper for manufacturing an optical disk, wherein the stamper is a resin stamper obtained by the method for manufacturing a stamper for manufacturing an optical disk according to claim 1 and having at least one concavo-convex pattern portion to which the concavo-convex pattern of an optical disk master is transferred.   A stamper for manufacturing an optical disc, wherein the stamper is a metal stamper having a concavo-convex pattern portion corresponding to the concavo-convex pattern portion of the resin stamper, which is duplicated based on the optical disc manufacturing stamper according to claim 2. A roll body;
An optical disc manufacturing stamper according to claim 2 or 3,
An optical disk manufacturing roll stamper, wherein the optical disk manufacturing stamper is wound around a roll body so as to cover an outer peripheral surface of the roll body.   5. The roll stamper for manufacturing an optical disk according to claim 4, wherein the concave / convex pattern portion of the stamper for manufacturing the optical disk is made 3 to 100 [mu] m higher than the periphery thereof. Providing a layer comprising a radiation curable resin on the base film;
While rotating the roll stamper for manufacturing an optical disk according to claim 4 or 5, the roll stamper and the radiation curable resin on the base film are brought into contact with each other, and the roll stamper and the radiation curable resin are in contact with each other. Irradiating the radiation curable resin with radiation to cure the radiation curable resin, and obtaining a pattern sheet on which the concave and convex pattern portion of the roll stamper is transferred;
A step of providing a recording layer sheet by providing at least a light reflection layer on the pattern sheet;
And a step of bonding the recording layer sheet and the optical disc substrate.

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