JP4360269B2 - Multilayer optical disc manufacturing method - Google Patents

Description

This invention relates to a method of manufacturing a high multi-layer optical disc of reproduction capability having multiple signal layers can be manufactured at low cost.

  Transparent substrate transmission type optical disk media represented by CD and DVD generally use a transparent substrate such as polycarbonate (hereinafter abbreviated as PC as appropriate), polymethyl methacrylate (hereinafter abbreviated as PMMA as appropriate), and glass. . This is because light transmittance is important in order to transmit the laser beam for reading and writing through the base material and to focus on the signal layer formed at the back of the substrate by utilizing the lens effect and narrowing down.

  On the other hand, in a read / write optical disk medium using a high NA (Numerical Aperture) optical system represented by Blu-ray-Disk (trade name, hereinafter abbreviated as BD as appropriate), which is being put into practical use recently, the transparency of the substrate. However, in any case, a multilayer optical disk with an increased capacity can be realized by providing a plurality of signal surfaces and laminating them.

  In this multi-layer optical disk, the pits and grooves on the first layer signal surface located on the support substrate surface are formed by injection molding (or injection molding), press molding, or photopolymer method using ultraviolet curable resin (hereinafter referred to as UV curable resin). (It is abbreviated as a 2P transfer method as appropriate), and an emboss transfer method using a semi-curable ultraviolet curable assist adhesive film or the like.

  A reflective film or recording film is coated on the pits and grooves on the first signal surface. This film is an Al reflective film, a magneto-optical film, a phase change film, a dye film, a hologram film, etc., which are usually employed in optical disk media, and the formation method is also a general technique, such as vacuum evaporation, sputtering, spin coating. Any method can be used as long as it can provide a desired shape and optically sufficient surface smoothness, such as die coating, dip coating, and spray coating.

  A second signal surface having pits and grooves is formed on the first signal surface on which the reflection film or the recording film is formed. The pits and grooves on the signal surface of the second and subsequent layers are formed by a 2P transfer method using an ultraviolet curable resin, an emboss transfer method using a semi-curable ultraviolet curable assist adhesive film, a photolithography method by mask exposure and etching, and the like. Further, a reflective film or recording film such as an Al reflective film, a magneto-optical film, a phase change film, a dye film, and a hologram film is formed on the film by a general method such as vacuum evaporation, sputtering, spin coating, die coating, It is coated by conventional methods such as dip coating and spray coating. In this way, the signal surfaces are laminated to form a multilayer optical disc. (See Non-Patent Document 1 below)

Nikkei Electronics March 31, 2003, no. 844, pp. 135-150

  In this case, the cover to be formed on the uppermost part is made by laminating and bonding a transparent film adopted by BD via an adhesive, a transparent film adhered by an ultraviolet curable adhesive, and a thick UV curable resin. There are things that are covered by coating, and there are no special restrictions.

  However, in the above-described conventional structure, as the signal layers are stacked, the surface accuracy such as film thickness uniformity and skew decreases, and minute dust and minute defects are easily caught, and the accuracy of the signal surface to be formed next is improved. Therefore, there has been a problem that the disc reproducing ability is lowered, for example, the focus and tracking are easily shifted.

  For this reason, the number of signal layers is limited. Furthermore, since the damage to the stamper increases, the number of sheets that can be transferred from the stamper per sheet is also limited. Therefore, it is necessary to frequently replace the stamper, resulting in an increase in the cost of the disk.

Therefore, the object of the present invention is to reduce the surface accuracy such as the film thickness uniformity skew caused by the lamination of the signal layers generated in the conventional multi-layered disk, increase the pinching of micro dust and micro defects, and the result. improve the signal surface accuracy problem drop occurring as the present invention is to provide a manufacturing method of a multilayer optical disc.

The above-described object of the present invention is to provide a flattened transparent optical disc that is positioned so as to cover the signal layer after the formation of concavities and convexities and the formation of a reflection film or recording film thereon, in a multilayer optical disc that performs recording and reproduction with a laser beam. Once the resin layer is formed, a signal surface having at least one of pits and grooves is formed on the flattened transparent resin layer, and the signal surface is flattened with an ultraviolet curable resin and a plastic master. It is filled with the transparent resin layer, irradiated with ultraviolet light from the plastic master side, and after curing the UV curable resin, the plastic master disk is peeled off, and the cured UV signal is transferred onto the flattened transparent resin layer. it is formed on the resin layer can be achieved by the method for producing a multi-layer optical disc.

  As a configuration example of the present invention, in the case of the surface read / write type, the support substrate serving as the core material may be a transparent body or an opaque body. That is, in addition to transparent plastics such as PC and PMMA, glass, and the like, opaque metal plates, papers including processed paper, plastics mixed with fillers, and the like can also be used. For example, there can be considered a disk in which a transparent polycarbonate injection substrate (hereinafter abbreviated as a PC injection substrate) is used as a support substrate and multilayered thereon.

  In the case of a disc on which a transparent PC injection substrate is used as a support substrate and a multilayer is formed thereon, the first layer signal surface located on the support substrate surface is formed by photolithography and precision plating as is done in normal optical disc manufacturing. It is formed by injection molding using a nickel stamper having at least one of minute pits and grooves formed on the surface.

  Thereafter, a reflective film or a recording film is coated thereon. This film is an Al reflective film, a magneto-optical film, a phase change film, a dye film, a hologram film, etc., which are usually employed in optical disk media, and the formation method is also a general technique, such as vacuum evaporation, sputtering, spin coating. Die coating, dip coating, spray coating, etc. are used.

  A flattened transparent resin layer is formed so as to cover at least one of the pits and grooves on which the reflective film or the recording film is formed. The method for forming the flattened transparent resin layer is not particularly limited, such as spin coating, roll coating, die coating, spray coating, and casting, but is performed using an ultraviolet curable resin that is cured by ultraviolet curing irradiation or heating. At this time, the resin may be in a semi-cured state in order to increase adhesion to the transfer resin layer formed thereon.

  The thickness of the transparent resin layer needs to be in a range that can be optically separated when reading and writing the signal surfaces positioned above and below the transparent resin layer, and the value is optimized for the system. A signal surface having at least one of pits and grooves is further formed on the flattened transparent resin layer.

  A plastic master (hereinafter abbreviated as “master” as appropriate) is prepared as the master of the signal surface. The master and the support substrate are opposed to each other, and the unevenness on the master surface is transferred by a conventional method such as a 2P transfer method. At the time of transfer, first, an ultraviolet curable resin is filled between the two by a press roll, vacuum pressure bonding, spin bonding, or the like, and ultraviolet light is irradiated from the plastic master side while maintaining this state. As a result, the ultraviolet curable resin is cured, and then the master is peeled from the cured ultraviolet curable resin to form an ultraviolet curable resin layer having surface irregularities transferred onto the PC support substrate. This surface becomes the second signal surface.

  Another method is to laminate a semi-cured UV curable assist adhesive film PSA (PRESSURE SENSITIVE ADHESIVE; pressure sensitive adhesive) on a support substrate in advance and emboss transfer the uneven signal of the master to this surface. is there.

  At this time, between the first signal surface and the second signal surface, a transparent resin layer having a flattened layer and a layer to which irregularities on the surface of the master were transferred (hereinafter referred to as a 2P transfer layer as appropriate) were sandwiched. It becomes a structure.

  Subsequently, a reflective film and a recording film are formed on the surface of the second signal layer. This film is a film commonly used for optical disks such as Al reflective film, Ag reflective film, magneto-optical film, metal phase change film, organic dye film, hologram film, and its formation method is also particularly limited such as vacuum deposition, sputtering, spin coating, etc. There is no.

  The flattened transparent resin positioned so as to cover at least one of the pits and grooves on which the reflective film and the recording film are formed on the surface of the second signal layer is formed by the above method. A signal surface having at least one of pits and grooves is further formed on the flattened transparent resin.

  A plastic master is prepared as a master for the signal surface, and the master and the support substrate are made to face each other. At the time of transfer, first, an ultraviolet curable resin is filled between the two by a press roll, vacuum pressure bonding, spin bonding, or the like, and ultraviolet light is irradiated from the plastic master side while maintaining this state. Thereby, the ultraviolet curable resin is cured.

  Thereafter, the master is peeled off from the cured ultraviolet curable resin, and an ultraviolet curable resin layer having surface irregularities transferred thereon is formed on the PC support substrate. This surface is the third signal surface. A multilayer optical disk (three-layer structure) can be formed by laminating signal surfaces in this way.

  In a multi-layer optical disc that performs recording / reproduction with a laser beam from one direction, after the formation of concavities and convexities on each signal layer and the formation of a reflective film or recording film thereon, a flattened transparent resin layer positioned so as to cover it is once Forming a signal surface having at least one of pits and grooves on the flattened transparent resin layer to form a signal layer in the multilayered disc. It is possible to improve the deterioration of surface accuracy such as film thickness uniformity and skew, occurrence of pinching of fine dust and micro defects, and further deterioration of the accuracy of the signal surface to be formed next. Further, it is possible to improve a decrease in the disk reproduction capability such as focus and tracking being easily shifted.

  This allows more layers. Furthermore, since the multilayer optical disc of the present invention can reduce damage to the stamper, the yield is improved, and as a result, the cost of the disc can be reduced.

  As an embodiment of the present invention, FIGS. 1A to 1F and FIGS. 2A to 2F show a manufacturing method for forming a multilayer optical disk of the present invention. In this case, a signal surface is provided on the multilayer optical disk substrate (core material). An example of a method for manufacturing a surface read / write type multilayer optical disc (three-layer structure) represented by a BD that is recorded and reproduced by applying a laser beam to the surface of a support substrate in a multilayer optical disc formed in a stacked manner will be described.

  In the case of the surface read / write type, the support substrate as the core material may be a transparent body or an opaque body. That is, in addition to transparent plastics such as PC and PMMA, glass, etc., opaque metal plates, papers containing processed paper, plastics mixed with filler, etc. may be used, but here, as one form, transparent PC injection A disk having a substrate (supporting substrate) and a multilayer (three-layer structure) formed thereon is taken up.

  1A to 1F and 2A to 2F show a manufacturing process of a multilayer optical disc (three-layer structure). FIG. 1F corresponds to FIG. 2A.

  FIG. 1A is an enlarged cross-sectional view of a support substrate having an uneven signal 33 formed on the surface. The first signal layer 11 located on the support substrate surface 12 is based on a nickel stamper in which at least one of minute pits and grooves is formed on the surface by photolithography and precision plating, as is done in normal optical disk manufacturing. , Formed by injection molding.

  A plan view of FIG. 1A is shown in FIG. 3A, and a side view is shown in FIG. 3B. The thickness of the PC injection board at this time is 1.1 mm.

  FIG. 1B is an enlarged cross-sectional view illustrating a process of coating the reflective film 13 or the recording film 14 on the first signal layer. The reflection film 13 or the recording film 14 is an Al reflection film, a magneto-optical film, a phase change film, a dye film, a hologram film, or the like usually employed in optical disc media, and the formation method thereof is also a general technique, such as vacuum evaporation. Methods, sputtering, spin coating, die coating, dip coating, spray coating, etc. are used.

  FIG. 1C is an enlarged view illustrating a process of forming a flattened transparent resin layer 15 positioned so as to cover at least one of pits and grooves on which the reflective film 13 or the recording film 14 is formed. It is sectional drawing. The method for forming the flattened transparent resin layer 15 is not particularly limited, such as spin coating, roll coating, die coating, spray coating, and casting, but is cured by ultraviolet irradiation or heating. A semi-cured state may be used in order to achieve adhesion with the transfer ultraviolet curable resin layer formed thereon.

  1D and 1E are enlarged cross-sectional views illustrating a process of forming a signal surface having at least one of pits and grooves on the flattened transparent resin layer 15.

  First, in the process shown in FIG. 1D, a plastic master 18 is prepared as a master for the signal surface. Next, a conventional method such as a press roll, a vacuum pressure transfer method, a spin bonding transfer method, or the like is used between the transparent resin layer 15 and the plastic master 18 that are flattened with an uncured ultraviolet curable resin 17 so as to prevent bubbles from entering. Fill.

  For example, in the case of the PC injection substrate 31 shown in FIG. 3A, the plastic master 18 having a signal layer has a thickness of 1.1 mm, for example, and is formed by injection molding with a Ni stamper that is common in the optical disc substrate process. . In general, a PC injection board is a disk having a thickness of 0.3 mm to several mm and a diameter of 120 mm. A side view having the surface unevenness signal 33 is shown in FIG. 3B.

  FIG. 1E is an enlarged cross-sectional view illustrating a process of transferring the unevenness on the surface of the plastic master disk by the 2P transfer method with the plastic master disk 18 and the support substrate facing each other. As a transfer method, for example, a 2P transfer method is used. First, as shown in FIG. 1D, it is flattened to prevent bubbles from entering by a conventional method such as a press roll, a vacuum pressure transfer method, or a spin bonding transfer method. After the uncured UV curable resin 17 is filled between the transparent resin layer 15 and the plastic master 18, the UV curable resin is cured by irradiating UV light from the plastic master while maintaining this state. An ultraviolet curable resin layer (2P transfer layer) 19 having a surface irregularity signal transferred thereon is formed on the PC support substrate by peeling from the cured ultraviolet curable resin. A second signal layer 20 is formed on the surface of an ultraviolet curable resin layer (referred to as a 2P transfer layer as appropriate) 19.

  1F and FIG. 2A are enlarged cross-sectional views of a two-layer structure of a disc having a second signal layer 20 formed on the surface by the steps of FIGS. In the multilayer optical disc (two-layer structure) shown in FIG. 1F and FIG. 2A, a planarizing layer 15 and a 2P transfer layer 19 made of transparent resin are sandwiched between the first signal surface 11 and the second signal surface 20. It becomes a structure. If the ultraviolet curable resin constituting the planarizing layer 15 is A and the ultraviolet curable resin constituting the 2P transfer layer is B for 2P transfer, the ultraviolet curable resin A and the ultraviolet curable resin B may be the same material or may have physical properties. Different materials may be used.

  As an example of the latter, the UV curable resin A employs a leveling property, good adhesion to the substrate, and a low curing shrinkage stress, and the UV curable resin B has a good transferability and a good peeling property from a plastic master. It is preferable to employ a material having good shape stability.

  Further, even if A and B are the same kind of ultraviolet curable resin, the mixing ratio of the monomer or oligomer as its component is adjusted, for example, by adjusting the Tg of the ultraviolet curable resin A to 50 ° C. The same effect can be found by adjusting the temperature to 70 ° C.

  FIG. 2B is a process of coating the reflective film 23 or the recording film 24 on the second signal layer. The reflection film 23 or the recording film 24 is an Al reflection film, a magneto-optical film, a phase change film, a dye film, a hologram film, or the like, which is usually employed in optical disk media. Method, sputtering method, spin coating, die coating, dip coating, spray coating, etc. are used.

  FIG. 2C is a process of forming a flattened transparent resin layer 25 positioned so as to cover at least one of the pits and grooves on which the reflective film or the recording film is formed. The method for forming the flattened transparent resin layer is not particularly limited, such as spin coating, roll coating, die coating, spray coating, and casting, but is cured by ultraviolet irradiation or heating. A semi-cured state may be used in order to achieve adhesion with the transfer ultraviolet curable resin layer formed thereon.

  As shown in FIG. 6, the thickness of the transparent resin layer 25 needs to be in a range that can be optically separated when reading and writing the signal surfaces located above and below the transparent resin layer 25, and the value is optimized for the system. For example, in BD, since the optical distance between the upper and lower signal surfaces is about 25 μm, the thickness of the transparent resin is (25 μm-2th signal forming layer thickness). That is, when the signal forming layer is 15 μm, the optimal thickness of the transparent resin layer is 10 μm.

  2D and 2E are enlarged cross-sectional views illustrating a process of forming a signal surface having at least one of pits and grooves on the flattened transparent resin layer 25. FIG.

  First, in the step shown in FIG. 2D, a plastic master 28 is prepared as a signal surface master. Next, a conventional method such as a press roll, a vacuum pressure transfer method, a spin bonding transfer method, or the like is used between the transparent resin layer 25 and the plastic master 28, which are flattened with an uncured ultraviolet curable resin 27 so that bubbles do not enter. Fill.

  The plastic master 28 having a signal layer is a resin such as PMMA or PC, but has excellent releasability with respect to an ultraviolet curable resin such as a cyclic polyolefin (trade name: Zeonex manufactured by Nippon Zeon Co., Ltd.). It is desirable to use

  Further, it is desirable to use a size (outer diameter) that is equal to or larger than that of the support substrate, for example, as shown in FIG. 4A (a plastic master having a diameter of 130 mm with respect to a substrate having a diameter of 120 mm). A side view having the surface unevenness signal 34 is shown in FIG. 4B.

  FIG. 2E is an enlarged cross-sectional view illustrating a process of transferring the unevenness on the surface of the plastic master disk by a 2P transfer method with the plastic substrate 28 (for example, the cyclic polyolefin shown in FIG. 4 (trade name: ZEONEX, manufactured by ZEON CORPORATION) facing the support substrate. As a transfer method, for example, a 2P transfer method is used, but first, as shown in Fig. 2D, bubbles do not enter by a conventional method such as a press roll, a vacuum pressure transfer method, or a spin bonding transfer method. After filling the uncured ultraviolet curable resin 27 between the transparent resin layer 25 and the plastic master 28 flattened in this manner, the ultraviolet curable resin is cured by irradiating ultraviolet light from the plastic master side while maintaining this state. After that, the master is peeled off from the cured ultraviolet curable resin, and the surface unevenness signal is transferred onto the PC support substrate. The second signal layer 30 is formed on the resin layer (2P transfer layer) 29 is formed. (Appropriately referred to as 2P transfer layer) UV-curable resin layer 29 surface.

  FIG. 2F is an enlarged cross-sectional view of the three-layer structure of the disc having the third signal layer 30 formed on the surface by the steps of FIGS.

  5A and 5B show enlarged cross-sectional views of the completed three-layer disc. FIG. 5A corresponds to FIG. 2F. 5B and 5C are enlarged cross-sectional views of a structure in which a cover layer is formed on the top. FIG. 5B shows a three-layer disk structure in which a cover layer 51 is formed by thickly coating and curing an ultraviolet curable resin, and FIG. 5C shows a PSA (PRESSURE SENSITIVE ADHESIVE; A three-layer disc structure in which a PC film cover layer 52 is formed on the adhesive layer 53 (laminate adhesion) using a pressure adhesive) is exemplified, but there is no particular limitation.

FIG. 6 shows a more specific structural example of the completed three-layer disc of FIGS. 5B and 5C. 6B corresponds to FIG. 5B, and FIG. 6C corresponds to FIG.
The thickness of the transparent resin layer 25 needs to be in a range that can be optically separated when reading and writing the signal surfaces positioned above and below the transparent resin layer 25, and the value is optimized for the system. For example, in FIGS. 5B and 5C, the optical distance between the upper and lower signal surfaces (in both the first and second signal layers, the second and third signal layers) is about 25 μm. The thickness of the transparent resin layer is (25 μm−1 or the thickness of the second signal forming layer). That is, when the signal forming layer is 15 μm, the optimal thickness of the transparent resin layer is 10 μm.

  In the three-layer optical disk shown in FIG. 6B and FIG. 6C, the planarizing layer 15 and 2P transfer layer 19 made of transparent resin, the second signal surface 20 and the second signal surface 20 are disposed between the first signal surface 11 and the second signal surface 20. Between the three signal surfaces 30, a planarizing layer 25 made of a transparent resin and a 2P transfer layer 29 are sandwiched. When the ultraviolet curable resin constituting the planarizing layers 15 and 25 is A and the ultraviolet curable resin constituting the 2P transfer layer is B, the ultraviolet curable resin A and the ultraviolet curable resin B may be the same material or materials having different physical properties. It doesn't matter.

  As an example of the latter, the UV curable resin A employs a leveling property, good adhesion to the substrate, and a low curing shrinkage stress, and the UV curable resin B has a good transferability and a good peeling property from a plastic master. It is preferable to employ a material having good shape stability.

Further, even if A and B are the same kind of ultraviolet curable resin, the mixing ratio of the monomer or oligomer as its component is adjusted, for example, by adjusting the Tg of the ultraviolet curable resin A to 50 ° C. The same effect can be found by adjusting the temperature to 70 ° C.
As a method for transferring the unevenness of the surface of the plastic master, a semi-cured UV curable assist adhesive film (PSA (PRESSURE SENSITIVE ADHESIVE)) is laminated on a support substrate in advance, There is also a method of embossing the uneven signal of the plastic master.

  Although the multilayer optical disk having the surface read / write structure has been described above, a disk having a structure for reading and writing through the transparent support substrate can be similarly formed. An example of a completed three-layer disk structure in this case is shown in FIG. Reference numeral 71 denotes a transparent support substrate such as PC injection, and 72 denotes an ultraviolet curable resin protective film.

  As an application example of the multi-layer disc of the present invention, as shown in FIG. 8A, two surface reading type multi-layer optical discs are bonded to each other around a support substrate to form an adhesive layer 85 to be multilayered on both sides of the substrate. Disc form is possible. Further, in the base material transmission type shown in FIG. 8B, a disk structure in which reading and writing can be performed from both sides is made by using two multilayered substrates as an adhesive layer 87 between the UV curable resin protective films.

  Furthermore, in the case of a double-sided read / write structure, light incident and reflection on the opposite signal surface can be reduced by configuring a portion corresponding to the center with a light blocking member. Thereby, stable signal reading and writing can be performed.

  FIG. 9 shows an example in which a metal support substrate 91 is used as a support substrate as another embodiment. Also in the case of a metal support substrate, it has the same structure as a transparent substrate and can be manufactured by the same method. In this case, as shown in FIG. 16, in forming the first layer signal surface and the second layer signal surface. In the surface unevenness transfer, the ultraviolet curable resin can be cured by irradiating the ultraviolet irradiation direction not only from the plastic master but also from the inner edge portion or the outer peripheral edge portion.

  In the case of a multi-layer optical disk with a metal support substrate, it is easy to ground from a machine base in a spin coating process, a turntable of a drive system, a crimping process, and a peeling process, and this has an advantage that dust adsorption due to static electricity can be reduced. This is effective in a process having a large number of processes, such as the multilayer optical disk of the present invention.

  As shown in FIG. 10, a multilayer disk having two layers on both sides can be formed as an example using a metal support substrate.

  FIGS. 11 to 13 are schematic diagrams illustrating the press roll method, the vacuum pressure transfer method, the spin bonding transfer method, and the like of the 2P transfer method described in FIGS. 1E and 2E.

} FIG. 10 is a schematic diagram illustrating a press-roll system.

  FIGS. 11 to 13 are schematic diagrams illustrating the press roll method, vacuum pressure transfer method, and spin bonding transfer method of the 2P transfer method described in FIGS. 1E and 2E.

  FIG. 11 is a schematic diagram for explaining a press-roll system. A transparent stamper 111 (e.g., Zeonex; trade name, manufactured by Nippon Zeon Co., Ltd.) and a support substrate 112 coated with an ultraviolet curable resin in a predetermined pattern are reversed and laminated with a press roll. Thereafter, the resin is cured by ultraviolet irradiation.

  FIG. 12 is a schematic diagram for explaining a vacuum pressure bonding transfer method (Pre-Coating & vacuum bonding method). A transparent stamper 121 (for example, Zeonex; trade name, manufactured by Nippon Zeon Co., Ltd.) and a support substrate on which an ultraviolet curable resin 122 is applied in a ring shape and spin-coated on the inner periphery thereof are reversed and bonded together in a vacuum. Thereafter, the resin is cured by ultraviolet irradiation.

  FIG. 13 is a schematic diagram for explaining a spin-bonding transfer method. A transparent stamper 131 (for example, Zeonex; made by Nippon Zeon Co., Ltd.) coated with multi-point UV curable resin on the inner periphery and a spin-coated support substrate coated with UV curable resin 132 in a ring shape on the inner periphery And the resin is cured by ultraviolet irradiation after spin bonding.

  FIG. 14 shows a state in which UV light is applied from the plastic master side 142 while maintaining this state after filling with the uncured ultraviolet curable resin 141 by the press roll, the vacuum pressure transfer method, and the spin bonding transfer method described in FIGS. After irradiating and curing the UV curable resin, the master is peeled from the cured UV curable resin, and the UV curable resin layer (2P transfer layer) 145 having the surface irregularity signal transferred thereon is formed on the PC support substrate 143. It is the schematic to explain.

  FIG. 15 shows a method of transferring unevenness on the surface of a plastic master by laminating a semi-cured UV curable assist adhesive film 151 (PSA (PRESSURE SENSITIVE ADHESIVE)) on a support substrate 152 in advance. This shows a method of embossing the uneven signal of the plastic master on this surface.

As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, The various deformation | transformation based on the technical idea of this invention is possible. For example, the numerical values given in the above embodiment are merely examples, and different numerical values may be used as necessary.

A to F are schematic explanatory views showing steps of a method for producing a multilayer optical disc (three-layer structure) of the present invention. A to F are schematic explanatory views showing steps of a method for producing a multilayer optical disc (three-layer structure) of the present invention. A and B are schematic explanatory views (a plan view and a side view) showing the structure of the multilayer optical disc of the present invention. A and B are schematic explanatory views (a plan view and a side view) showing the structure of the multilayer optical disc of the present invention. A and B are schematic explanatory views (sectional views) showing a completed multilayer optical disc of the present invention. It is a schematic explanatory drawing (sectional drawing) which shows the structural example of the completed multilayer optical disk of this invention. It is a schematic explanatory drawing (sectional drawing) which shows other embodiment of the multilayer optical disk of this invention. It is a schematic explanatory drawing (sectional drawing) which shows the application example of the multilayer optical disk of this invention. It is a schematic explanatory drawing (sectional drawing) which shows other embodiment of the multilayer optical disk of this invention. It is a schematic explanatory drawing (sectional drawing) which shows the application example of other embodiment of the multilayer optical disk of this invention. It is a schematic explanatory drawing which shows the transfer method of the multilayer optical disk of this invention. It is a schematic explanatory drawing which shows the transfer method of the multilayer optical disk of this invention. It is a schematic explanatory drawing which shows the transfer method of the multilayer optical disk of this invention. It is a schematic explanatory drawing which shows the formation method of the transfer layer of the multilayer optical disk of this invention. It is a schematic explanatory drawing which shows the other transfer method of the multilayer optical disk of this invention. It is a schematic explanatory drawing which shows the transfer method of other embodiment of the multilayer optical disk of this invention.

Explanation of symbols

11 First signal layer 12, 31, 71, transparent support substrate 13, 23 Reflective film 14, 24, 103, 105 Recording film 15, 25, 73, 95, 104 Flattened transparent resin layer 17, 27 Uncured ultraviolet light Cured resin 18, 28, Plastic master 19, 29 UV curable resin layer 20 Second signal layer 30 Third signal layer 33, 34 Surface uneven signal 51, 72, 92 UV curable resin cover 52, 93, 101 PC film cover 53, 94, 102, 151 Adhesive material PSA (PRESSURE SENSITIVE ADHESIVE; pressure sensitive adhesive) layer 85, 87 Adhesive layer 91, 106 between UV curable resin protective films Metal support substrates 111, 131, 142, 153 Transparent stamper (Zeneox)
112, 122, 132, 141 UV curable resin (uncured)
110, 121, 133, 143, 152 Support substrate 161 Chrome mask 162 Metal plate 163 Photoresist 165 Surface unevenness forming metal plate S Sputtering L Peeling T Vacuum chamber U Ultraviolet irradiation

Claims (5)

Forming at least one of pits and grooves covered with a reflective film or a recording film on the signal surface of the first layer formed on the support substrate;
Forming a planarized transparent resin layer so as to cover it,
Forming a signal layer having at least one of pits and grooves covered with a reflective film or a recording film on the flattened transparent resin layer,
The step of forming the signal layer includes
Transfer of the signal layer is performed on a plastic master, and an ultraviolet curable resin is filled between the plastic master and the flattened transparent resin layer,
Irradiate ultraviolet light from the plastic master ,
A method for producing a multilayer optical disk, comprising: a step of peeling the plastic master after curing an ultraviolet curable resin to form an ultraviolet curable resin layer having a concavo-convex signal transferred on the flattened transparent resin layer. A method for producing a multilayer optical disc, wherein the transfer of the signal layer comprising the ultraviolet curable resin layer to which the concavo-convex signal is transferred according to claim 1 is performed by a photopolymer method using an ultraviolet curable resin. A method for producing a multilayer optical disc, wherein filling of the ultraviolet curable resin before transfer of the signal layer according to claim 1 is performed by a press roll method. A method for producing a multilayer optical disk, wherein filling of the ultraviolet curable resin before transfer of the signal layer according to claim 1 is performed by a vacuum pressure bonding method. A method for producing a multilayer optical disc, wherein the ultraviolet curable resin is filled by spin bonding before transferring the signal layer according to claim 1 .

Images