JP2006331537A - Manufacturing method of optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of an optical disk for a blue-violet laser, without material loss in coating and without coating nonuniformity of an adhesive, while sticking of uniform thickness is made possible and film thickness can be controlled. <P>SOLUTION: The manufacturing method of an optical disk in which an adhesive layer, a reflective metal, a signal recording pattern, a transparent sheet and a hard coat layer are laminated on a disk substrate in this order comprises at least: a process for press-contacting a cylinder surface around which a stamper forming a signal recording pattern is wound with an ultraviolet curable resin surface formed on the back surface of the transparent resin sheet and continuously transferring the signal recording pattern to the ultraviolet curable resin surface; a process for sandwiching the adhesive layer between the transferred signal recording pattern surface and the surface of the disk substrate and sticking them together by squeezing them from the transparent resin sheet side by a roller; and blanking and cutting a sheet for a disk into a disk shape. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical disc manufacturing method.

  In recent years, the capacity of optical discs has been increasing, and Blu-ray Discs (hereinafter referred to as BD) using a blue-violet light source (wavelength around 400 nm) are products as optical discs with higher density and larger capacity than DVD discs. It is becoming. The BD has a very thin signal recording layer with a transparent resin thickness of about 0.1 mm from the disk surface to the signal recording layer, and forms a fine laser spot using a lens with an NA of about 0.85. Signal recording or signal reproduction is performed on the recording layer. BD has a recording capacity of about 25 Gbytes for single-sided single-layer recording and about 50 Gbytes for single-sided dual-layer recording, and is a large-capacity medium about five times that of DVD.

  A method for manufacturing a BD will be described. First, a signal recording layer is formed on a substrate having a thickness of 1.1 mm. Next, a signal recording layer having a thickness of 0.1 mm is produced by laminating a thin resin sheet or applying an ultraviolet curable resin on the signal recording layer. There is a method of manufacturing a BD having a total thickness of 1.2 mm by the above method. This method has a problem that the manufacturing process is complicated and there are many processes. Manufacturing processes such as bonding resin sheets or applying resin are complicated. In addition, there are many manufacturing processes because of the multilayer structure.

  In another method, first, a signal recording pattern is formed on a thin resin sheet (0.07 to 0.09 mm thick). Next, there is a method of manufacturing a BD having a total thickness of 1.2 mm by a method of bonding the resin sheet of the signal recording layer and a substrate having a thickness of 1.1 mm.

  However, since the shape of the pit formed in the signal recording pattern is as small as 0.3 to 0.149 μm, and the injection molding method has a very fine pit depth of 0.05 μm even in a region where the transfer rate is low, the disk The thickness standard from the surface to the signal recording pattern is limited to be as thin as 0.1 mm, and there is a problem that it is difficult to handle it in the manufacturing process. In addition, a hard coat and an antifouling layer are indispensable because they are susceptible to scratches and dirt on the disk surface. Further, in a multi-layered process such as bonding and resin coating, a highly accurate manufacturing technique is required for thickness control, and the thickness unevenness from the disk surface to the signal recording layer needs to be cleared of ± 2 μm tolerance. Since the required quality is high, the cost increases due to product defects.

  From the above problems, there are problems such as a high manufacturing cost of the manufacturing apparatus, a long manufacturing cycle time, and a high product cost.

  A conventional BD manufacturing method shown in FIG. 8 will be described. First, a disk substrate is formed using an injection molding machine 31 in which a stamper on which a signal recording pattern is formed is attached to a mold. Next, a silver reflecting layer is formed on the disk substrate 32 with a signal recording pattern having a thickness of 1.1 mm by using the sputtering device 33. Subsequently, an adhesive is applied on the silver reflective layer using a spin coat 35. Thereafter, the cover layer (signal recording layer such as a transparent resin) and the disk base material are accurately positioned and bonded using the positioning and bonding machine 36. Next, the adhesive is cured using an ultraviolet irradiator 37. Next, the adhesive burr is scraped off by using a polishing machine 38. Subsequently, a hard coat layer is formed to a thickness of 1 μm on the cover layer (signal recording layer) using the spin coat 39. Next, the hard coat layer is cured using the ultraviolet irradiator 40 to produce the BD product 41.

In the conventional injection molding of a general manufacturing method, when the signal recording pattern has a submicron size, the transfer is incomplete, and the structure is rounded or generally shallow. It is said that the reason why the transferability in the conventional method is low is that the resin viscosity at the time of melting is high, so that it cannot enter a fine structure. Also, if the temperature of the injection mold is raised, the resin is filled, the mold is sufficiently cooled, and the product is taken out, the transferability will surely improve, but the molding time will be longer, and burr defects will easily occur in the product. . For this reason, it is certain and unrealistic that the production efficiency is lowered.

  A manufacturing method that does not use injection molding has also been proposed. In this manufacturing method, a disk substrate is manufactured not in the injection molding method but in the shape of a sheet, and in the middle of the process, a method of punching into a disk shape is shown. (See Patent Document 1).

  In addition, in the production of a BD signal recording layer, it is a method of forming a signal recording pattern by spin-coating a liquid UV curable resin on a circular base material and transferring a recording layer original plate, and has a good transferability. There has also been proposed a method for manufacturing the. However, in the case of spin coating, about half of the material is lost, and the difference in film thickness between the center and the peripheral part is likely to occur, making it difficult to control the film thickness.

  Furthermore, in the conventional method, since the adhesive is spin-coated to bond the signal recording layer and the disk base material, thickness variation occurs between the central portion and the peripheral portion. In addition, in the spin coating, since the ultraviolet curable resin remains as burrs at the edge of the base material, a polishing step is required.

The known literature is described below.
International Publication No. 01/086648 Pamphlet

  The problem of the present invention is that in the BD production method, there is no material loss in spin coating application such as adhesive, there is no uneven application of the adhesive, and the thickness at the center and the peripheral part can be uniformly bonded, Provide a manufacturing method that can control the film thickness, does not cause burr defects in the product, shortens the manufacturing cycle time, and improves the production efficiency, and uses the manufacturing method to provide a high quality and low manufacturing cost. To provide BD.

  The invention according to claim 1 of the present invention has a disc shape in which an adhesive layer, a reflective metal, a signal recording pattern, a transparent sheet, and a hard coat layer are laminated in that order on a disc base material. In a method for producing an optical disc of a method of reading information from a signal recording layer using a blue-violet laser having a wavelength of around 400 nm as a cut optical disc, a stamper having a signal recording pattern wound around a cylinder is used. A step of pressing the surface of the stamper and the surface of the ultraviolet curable resin formed on the back surface of the transparent resin sheet to continuously transfer the signal recording pattern to the transparent resin sheet; and a signal recording pattern in which the signal recording layer is formed on the transparent resin sheet Glue together with a roller from the transparent resin sheet side with an adhesive layer sandwiched between the surface and the surface of the disk substrate Degree and, a step of punching cutting the sheet disc tailored Ri 該貼 the disk shape, a manufacturing method of the optical disc, characterized in that to produce the optical disc with the configuration including at least.

  In the invention according to claim 2 of the present invention, the stamper on which the signal recording pattern is formed uses a stamper manufactured by nickel electroforming, and the cylinder uses a surface in which a magnetic substance is embedded. The method for producing an optical disk according to claim 1.

  The invention according to claim 3 of the present invention is characterized in that the ultraviolet curable resin is a resin containing at least urethane acrylate, an acrylic monomer, and a photopolymerization initiator. It is.

  The invention according to claim 4 of the present invention is the production of an optical disc according to any one of claims 1 to 3, wherein the transparent resin sheet is a polycarbonate sheet having a hard coat layer formed on a surface thereof. Is the method.

  The optical disk according to any one of claims 1 to 3, wherein the transparent resin sheet is a triacetyl cellulose sheet having a hard coat layer formed on a surface thereof. This is a manufacturing method.

  The invention according to claim 6 of the present invention is characterized in that the disk base material is a transparent resin and the adhesive is a transparent ultraviolet curable resin. This is a manufacturing method of the described optical disk.

  The invention according to claim 7 of the present invention is that the disk substrate is paper, polylactic acid, or a cellulose derivative, or a composite thereof, and the adhesive is an ultraviolet curable resin. 6. The method for producing an optical disc according to claim 1, wherein the optical disc is produced.

  The optical disk according to any one of claims 1 to 7, wherein a coating layer having an antifouling function is formed on a surface of the hard coating layer. This is a manufacturing method.

  The invention according to claim 9 of the present invention has a disc shape in which an adhesive layer, a reflective metal, a signal recording pattern, a transparent sheet, and a hard coat layer are laminated in that order on a disc base material. In a method of manufacturing an optical disc of a method of reading information from a signal recording layer using a blue-violet laser having a wavelength of around 400 nm as a cut optical disc, a stamper having a signal recording pattern wound around a cylinder is used. A step of pressing the surface of the stamper and the surface of the ultraviolet curable resin formed on the back surface of the transparent resin sheet to continuously transfer the signal recording pattern to the transparent resin sheet; and the transparent resin sheet of the signal recording layer is larger than the disk shape. A step of cutting, a step of forming a reflective metal on the signal recording pattern surface of the cut signal recording layer, and a reflective metal surface of the signal recording layer A step of laminating and laminating with a roller from the transparent resin sheet side with an adhesive layer sandwiched between the surface of the disc substrate, and a step of punching and cutting the laminated disc sheet into a disc shape; Is a method for producing an optical disk, characterized in that an optical disk is produced with a configuration including at least the above.

  By producing a BD using an ultraviolet curable resin in a spinless manner, material loss can be reduced and there is no polishing process, so the manufacturing cost is reduced and the film thickness distribution accuracy is improved because it is bonded together with a roller. High quality BD can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional side view for explaining a method for producing an optical disc (hereinafter referred to as BD) of the present invention. In the present invention, an optical disk using a blue-violet laser having a wavelength of about 400 nm and reading information from a signal recording layer 56 including a signal recording pattern 54, a transparent sheet 55, and a hard coat layer 58, 2 / adhesive layer 52 / reflective metal 53 / signal recording pattern 54 / transparent sheet 55 / hard coat layer 58. The production method is an optical disc production method for producing a BD with a configuration including at least the following steps, which will be described below.

  In FIG. 1A, first, an ultraviolet curable resin 57 is formed in a layer form on the entire back surface of the transparent resin sheet 55. Next, by using a stamper formed with a signal recording pattern 54 wound around a cylinder, the surface of the ultraviolet curable resin 57 is pressure-bonded to the surface of the cylinder stamper so that the signal recording pattern 54 is made of a transparent resin sheet. Continuous transfer onto the surface. Through the above steps, the signal recording layer 56 laminated with the hard coat layer 58 / transparent sheet 55 / signal recording pattern 54 on the front side is produced. In this method, it is possible to continuously transfer the fine-shaped signal recording pattern 54 onto the surface of the ultraviolet curable resin 57 with high accuracy.

  In FIG. 1B, from the transparent resin sheet side with the adhesive layer 52 sandwiched between the signal recording pattern 54 surface side formed on the transparent resin sheet of the signal recording layer 56 and the surface of the disk substrate 51. Lay it together with a roller. In this method, the distance between the upper and lower rollers and the pressurization thereof are controlled, so that the thickness of the layer can be made uniform.

  In FIG. 1C, the bonded disc sheet is punched and cut into a disc shape. The BD 50 is manufactured through the above steps.

  1A and 1B, the step of forming the hard coat layer 58 on the surface of the transparent sheet 55, and the signal recording pattern of the signal recording layer 56 between FIGS. 1B and 1C. The description of the process with the process of forming the reflective metal 53 on the 54th surface side is omitted.

  An embodiment of an optical disc manufacturing method that reads information using a blue-violet laser (wavelength around 400 nm) will be described below.

  FIG. 2 shows a stamper 1 on which a signal recording pattern 2 is formed. There are two methods for producing the original of the signal recording pattern 2: a production method by drawing a laser beam and a production method by drawing an electron beam. A plate having a resist on the surface is preferably a square plate (7-inch size) larger than the disk shape. After developing the resist plate on which the signal recording pattern is drawn, a conductive film is formed on the exposed plate surface, and then a nickel metal layer made of the signal recording pattern is formed by nickel electroforming to form a nickel stamper. The thickness of the stamper is preferably about 100 to 300 μm in consideration of the rigidity during bending and the durability during manufacturing.

  Next, FIG. 3 shows a roll in which a roll stamper 3 is mounted on the surface of the cylinder 4. As a method of fixing the stamper 1 to the cylinder 4, there are a method of fixing with a double-sided tape, a method of fixing the cylinder with a fixing fastener, a method of fixing the end by welding or soldering, and the like. .

  In the optical disc manufacturing method of the present invention, the signal recording pattern is formed by continuous transfer onto an ultraviolet curable resin, and since a liquid ultraviolet curable resin is used at room temperature, a signal recording pattern with a high-definition diffraction grating pattern is used. Even so, high-precision transferability is possible. Here, it is important to apply an ultraviolet curable resin having a viscosity of 5000 cps or less to an ultraviolet curable resin capable of transferring a structure having a size of about 0.1 μm with an accuracy within 5%.

In the present invention, the ultraviolet curable resin refers to a resin that is cured by ultraviolet rays (UV). A typical radical polymerization reaction resin is an acrylic resin having an acryloyl group in the molecule, and is an epoxy acrylate, urethane acrylate, polyester acrylate, polyol acrylate oligomer, polymer and monofunctional, bifunctional, or polyfunctional. Functional polymerizable (meth) acrylic monomers such as tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate , Mixtures of monomers, oligomers, polymers, etc., such as pentaerythritol tetraacrylate.

  There exists a photoinitiator as what is mix | blended with ultraviolet curable resin. Examples of the photopolymerization initiator include benzophenone, diethylthioxanthone, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- ( Methylthio) phenyl] -2-morpholinopropane-1, acylphosphine oxide, etc., but the photopolymerization initiator does not react 100%, and unreacted ones adversely affect performance. It should be added in an amount in the range of 1 to 7% by weight, preferably 0.5 to 5% by weight, so that no uncured part remains.

  Among the UV curable resins, the cured film of urethane acrylate has excellent coating properties such as Young's modulus, elongation, strength, resilience, and scratch resistance, and a tough film can be formed. Here, the urethane acrylate is a urethane acrylate having a urethane bond and an acryloyl group in the molecular chain (corresponding to claim 2).

  The types of transparent resin sheets include polyethylene film, polypropylene film, polystyrene film, acrylic film, polyester film, polycarbonate film, cycloolefin film, etc., but it has high transparency, adhesion with UV curable resin, heat resistance, and processability. Taking into account, polycarbonate sheet is good.

  FIG. 4 is an explanatory diagram for transferring a signal recording pattern to the transparent resin sheet 8 using the transfer device of the present invention. In the transfer device of the present invention, the ultraviolet curable resin 6 applied from the application nozzle 5 is applied to the back surface side of the transparent resin sheet 8, and then pressed onto the roll-shaped stamper 7 by the nip roll 9. Transfer the recorded pattern to. Here, since the resin is squeezed out by the nip roll 9, there is an advantage that bubbles are difficult to enter. Subsequently, by using the ultraviolet irradiator 10, it is cured and the signal recording pattern is fixed to the transparent resin sheet 8 to form a signal recording layer sheet.

  Next, a thin film of aluminum, silver, or an alloy thereof is formed on the sheet of the signal recording layer by a long roll sputtering method or a vapor deposition method to form a reflective metal ( (Omitted in the figure).

  Next, FIG. 5 is an explanatory diagram of a device for laminating a signal recording layer sheet and a disk substrate. A signal recording layer sheet (signal recording pattern transfer sheet 16) is supplied into the apparatus from the upper right side of the figure, and at the same time, the disk base material 12 is inserted by intermittent feeding from the lower right side of the figure, and the signal recording pattern transfer sheet 16 is reflected. The ultraviolet curable adhesive 14 is discharged between the surface of the conductive metal layer and the disk substrate 12, and the bonding roll 13 is bonded together while squeezing in the direction of the arrow. Subsequently, it is cured by an ultraviolet irradiator 17. If the disk base material is a transparent resin and the adhesive is an ultraviolet curable type, the curing time can be shortened and the production speed can be improved. In addition, it is a position movement which moves backward from the upper leveling roll 13 to the lower leveling roll 13 in the figure, and during this time, the ironing operation is performed. Then, it returns to the position of the upper leveling roll 13 (corresponding to claim 3).

FIG. 6 is an explanatory view of a flat plate punching machine. Next, in the disc-shaped punching device 19, the BD of the present invention can be performed by moving the bonded disc substrate / signal recording pattern sheet 20 in the direction of the arrow and punching it into a disc shape. Unlike conventional CDs and DVDs, they have a very sensitive effect on scratches and dirt on the disk surface. Therefore, when a bare disk is used, an antifouling coat is required on the hard coat surface of the BD. The BD production method of the present invention is a method of continuously applying a hard coat or an antifouling coating in a sheet state, and is efficient and inexpensive (Claims 4, 5, and 6).

  Recently, products with less environmental impact have been recognized not only for improving the corporate image, but also for their commercial value. In the case of BD, it is also possible to use a biodegradable material such as paper, polylactic acid, or a cellulose derivative as a disk substrate (claim 7).

  Furthermore, it is common to use a polycarbonate sheet as the transparent resin sheet, but as a product with less environmental impact by using triacetyl cellulose (TAC), which is a plant material as an alternative and has excellent optical properties. Appeal (claim 5).

  Considering the workability of exchanging the stamper, the nickel stamper can be easily exchanged by using a magnet cylinder (manufactured by Friendship Co., Ltd.) with a magnetic material embedded in the cylinder.

  FIG. 7 is an explanatory diagram for producing an optical disk using a small manufacturing apparatus. In the case of a small manufacturing apparatus, after forming the sheet 22 having the signal recording pattern transferred to the transparent resin sheet by the ultraviolet irradiation device 21, the transferred sheet 22 is cut into a sheet 23 having a size larger than the disk. Is good. Subsequently, after a reflective metal layer is formed on the signal-cut pattern recording sheet 23 that has been cut using a sputtering apparatus 24, the reflective metal layer / signal is bonded with an ultraviolet curable resin adhesive using a bonding apparatus 27. The recording pattern 25 is bonded to a substrate larger than the disk, for example, a 7-inch substrate, and the sheet 26 bonded to the substrate is cured by an ultraviolet irradiator 28, and then a disk shape punching machine 29 is used to form a disk.

It is a side cross-sectional process drawing explaining the manufacturing method of the optical disk of this invention. The top view which shows the shape of the stamper of this invention. The figure which wound the stamper around the cylinder of the present invention. Schematic of the apparatus which transfers a signal recording pattern to a transparent resin sheet. Schematic of the apparatus which bonds together using an ultraviolet curing resin intermittently. Schematic of a flat punching device. Schematic of the small manufacturing apparatus of this invention. Conventional manufacturing equipment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Stamper 2 ... Signal recording pattern 3 ... Roll-shaped stamper 4 ... Cylinder 5 ... Coating nozzle 6 ... Ultraviolet curable resin 7 ... Roll-shaped stamper 8 ... Transparent resin sheet 9 ... Nip roll 10 ... Ultraviolet irradiation machine 11 ... Substrate for disks (7 Inch □) with signal recording pattern sheet pasted 12 ... Disc substrate (7 inch □)
DESCRIPTION OF SYMBOLS 13 ... Pasting roll 14 ... UV curable resin 15 ... Dispenser 16 for application | coating ... Signal recording pattern transfer sheet 17 ... Ultraviolet irradiation machine 18 ... The thing which the signal recording pattern sheet affixed on the board | substrate for disks (7 inch (square)) 19 ... Punching Machine 20 ... Bonded disk substrate / signal recording pattern sheet 21 ... Continuous UV curable resin molding machine 22 ... Transferred sheet 23 ... Sheet cut signal recording pattern sheet 24 ... Sputter device 25 ... Reflective metal layer / signal Recording pattern sheet 26 ... Sheet 27 bonded to substrate ... Bonding device 28 ... UV irradiation device 29 ... Punching device 30 ... Stocker 31 ... Injection molding machine 32 ... Disc substrate 33 with signal ... Sputtering device 34 ... Reflectivity Metal layer / disk substrate 35 ... spin coater 36 ... positioning and bonding machine 3 ... ultraviolet ray irradiation device 38 ... grinding machine 39 ... spin coater 40 ... ultraviolet ray irradiation device 41 ... stocker 50 ... optical disk, Blu-ray Disc (BD)
DESCRIPTION OF SYMBOLS 51 ... Disc base material 52 ... Adhesive layer 53 ... Reflective metal 54 ... Signal recording pattern 55 ... Transparent sheet 56 ... Signal recording layer 57 ... Ultraviolet curable resin 58 ... Hard coat layer

Claims (9)

An optical disk cut into a disk shape, in which an adhesive layer, a reflective metal, a signal recording pattern, a transparent sheet, and a hard coat layer are laminated in that order on a disk substrate, is bluish purple in the vicinity of a wavelength of 400 nm. In a method for producing an optical disk using a laser and reading information from a signal recording layer,
Using a stamper formed with a signal recording pattern wound around a cylinder, the signal recording pattern is continuously attached to the transparent resin sheet by pressing the stamper surface of the cylinder and the surface of the UV curable resin formed on the back surface of the transparent resin sheet. A transfer process;
A step of squeezing with a roller from the transparent resin sheet side with an adhesive layer sandwiched between the signal recording pattern surface formed with the signal recording layer on the transparent resin sheet and the surface of the disk substrate; and ,
A step of punching and cutting the bonded disc sheet into a disc shape,
An optical disc manufacturing method comprising manufacturing an optical disc with a configuration including at least.   2. The optical disc according to claim 1, wherein the stamper on which the signal recording pattern is formed uses a stamper made of nickel electroforming, and the cylinder uses a magnetic material embedded in the surface. Manufacturing method.   3. The method for producing an optical disk according to claim 1, wherein the ultraviolet curable resin is a resin containing at least urethane acrylate, an acrylic monomer, and a photopolymerization initiator.   4. The method for producing an optical disc according to claim 1, wherein the transparent resin sheet is a polycarbonate sheet having a hard coat layer formed on a surface thereof.   4. The method for producing an optical disk according to claim 1, wherein the transparent resin sheet is a triacetyl cellulose sheet having a hard coat layer formed on a surface thereof.   6. The method of manufacturing an optical disk according to claim 1, wherein the disk base material is a transparent resin, and the adhesive is a transparent ultraviolet curable resin.   6. The disk substrate according to claim 1, wherein the disk base material is paper, polylactic acid, or a cellulose derivative, or a composite thereof, and the adhesive is an ultraviolet curable resin. 2. A method for producing an optical disc according to item 1.   8. The method for producing an optical disk according to claim 1, wherein a coating layer having an antifouling function is formed on the surface of the hard coating layer. An optical disk cut into a disk shape, in which an adhesive layer, a reflective metal, a signal recording pattern, a transparent sheet, and a hard coat layer are laminated in that order on a disk substrate, is bluish purple in the vicinity of a wavelength of 400 nm. In a method for producing an optical disk using a laser and reading information from a signal recording layer,
Using a stamper formed with a signal recording pattern wound around a cylinder, the signal recording pattern is continuously attached to the transparent resin sheet by pressing the stamper surface of the cylinder and the surface of the UV curable resin formed on the back surface of the transparent resin sheet. A transfer process;
Cutting the transparent resin sheet of the signal recording layer larger than the disk shape;
Forming a reflective metal film on the signal recording pattern surface of the cut signal recording layer;
A process of squeezing with a roller from the transparent resin sheet side with an adhesive layer sandwiched between the reflective metal surface of the signal recording layer and the surface of the disk substrate; and
A step of punching and cutting the bonded disc sheet into a disc shape,
An optical disc manufacturing method comprising manufacturing an optical disc with a configuration including at least.

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