JP2006331572A - Manufacturing method of optical recording medium and optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayered recording medium having high quality and high durability in a manufacturing method of a multilayered optical recording medium. <P>SOLUTION: The manufacturing method of the optical recording medium has steps of: forming a recording layer having a rugged pattern and a reflection layer on the surface of a sheet-like substrate; stacking a plurality of sheet-like substrates on which the recording layers are formed while being positioned; collectively processing the plurality of stacked sheet-like substrates into a prescribed contour shape; and forming a protective layer on the side surfaces of the plurality of processed sheet-like substrates. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an optical recording medium having a multilayer structure in which a plurality of sheets having recording layers formed thereon are overlapped, and an optical recording medium manufactured using the method.

  In recent years, optical recording media have been required to be small and large-capacity optical recording media, and recording media in which a plurality of recording layers are formed on a substrate surface have been proposed. Specifically, a recording layer composed of a plurality of recording films such as a recording film and a dielectric film is formed on a substrate on which a signal pattern is formed, and further, the recording film and the recording film are formed on the recording layer via the signal pattern forming layer. Another recording layer made of a dielectric film or the like is formed. If necessary, an optical recording medium having a plurality of recording layers on one substrate surface is formed by repeatedly forming a signal pattern forming layer and a recording layer, and finally forming an organic protective film on the recording layer. Is. It is known that a recording medium having a similar multilayer structure can be formed for a recording medium having a recording layer formed of a single layer film and a recording medium having a reflection layer such as a ROM. The light incident surface for recording / reproducing and erasing information can be from either the substrate surface side or the organic protective layer surface side on the recording layer, and one surface or both surfaces can be used. However, it is easier to reduce the thickness of the light-transmitting substrate if it is performed from the organic protective layer surface side, so it is possible to increase the NA (aperture) of the objective lens of the pickup, which is advantageous for increasing the density. It is known that

As a method of forming a plurality of recording layers on the one substrate surface, an optical recording medium manufacturing method and an optical recording medium disclosed in Japanese Patent Application No. 2005-036110 have been proposed. Specifically, a signal pattern and a reflection film or recording film are formed on a sheet-like base material, and after laminating a plurality of them, processing them into a disk shape at a time, so that the uniformity of the distance between each layer and the deviation of each layer are achieved. In addition to solving the problem of core accuracy, high quality is ensured without repeating complicated processes and without disposing a transparent stamper.
Japanese Patent Application No. 2005-036110

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing an optical recording medium having the above multi-layer structure and an optical recording medium having a higher quality and higher durability, and a method for producing the multi-layer recording medium. .

  In order to achieve the above goal, a state in which a step of forming a recording layer and a reflective layer having a concavo-convex pattern on the surface of a sheet-like substrate and a plurality of the sheet-like substrates on which the recording layer is formed are positioned relative to each other A step of superimposing, a step of collectively processing the plurality of sheet-like base materials superposed on each other, and a step of forming a protective layer on a side surface of the plurality of processed sheet-like base materials. A method for manufacturing an optical recording medium is provided.

  According to the present invention, it is possible to provide a multi-layered recording medium having a high quality and high durability in a method for manufacturing a multi-layered optical recording medium and an optical recording medium.

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

  As a first embodiment of the present invention, a protective layer is formed using a resin sheet or film in the step of providing a protective layer on the side surface of the optical recording medium among the surfaces of a plurality of laminated sheet base materials and supporting substrates. It is characterized by doing.

  The second aspect of the present invention is characterized in that in the step of providing a protective layer on the side surface of the optical recording medium among the surfaces of the plurality of laminated sheet base materials and the support substrate, the protective layer is formed with a liquid resin. To do.

  FIG. 1 is a schematic cross-sectional view of a four-layer optical recording medium manufactured according to the first embodiment of the present invention.

  The four-layer optical recording medium 112 manufactured according to the first embodiment of the present invention has a sheet-like base material (102, 105, 108) on which a signal pattern is formed and a signal pattern on a support substrate 111 on which the signal pattern is formed. A recording layer or a reflective layer (101, 104, 107, 110) is formed on the substrate, the sheet and the support substrate are laminated via an adhesive layer (103, 106, 109), and the laminate is a protective layer sheet 100. It is protected by.

  FIG. 2 is a schematic cross-sectional view of a four-layer optical recording medium produced according to the second embodiment of the present invention. The four-layer optical recording medium 21 produced according to the second embodiment of the present invention has a sheet-like base material (102, 105, 108) on which a signal pattern is formed and a signal pattern on a support substrate 111 on which the signal pattern is formed. A recording layer or a reflective layer (101, 104, 107, 110) is formed on the substrate, the sheet and the support substrate are laminated via an adhesive layer (103, 106, 109), and the laminate is a protective layer resin 20. It is protected by.

  The production method will be described in detail below.

  FIG. 3 schematically shows the production process of each recording layer in the production method of the optical recording medium according to the present invention.

  First, a sheet-like base material 30 processed into a sheet shape is prepared. As a method of forming a signal pattern on the sheet-like base material, the sheet-like base material 30 is made of a thermoplastic resin, the sheet-like base material is superimposed on the stamper 33, and after pressing and heating or both, There is a method of forming a signal pattern directly on a sheet-like substrate by cooling as necessary and peeling from the stamper. In addition, an ultraviolet curable resin, a thermosetting resin, or a dry photopolymer film (not shown) is formed on the sheet-like base material and stamper, and the stamper and the sheet-like base material are overlapped to heat energy rays such as ultraviolet rays or heat. There is also a method of forming a signal pattern forming layer on a sheet-like substrate by peeling the stamper after curing the resin layer by the above method. Furthermore, a method of forming a sheet-like substrate having a signal pattern by applying or superposing a liquid or sheet-like resin in an uncured or semi-cured state on a stamper and curing the resin by ultraviolet rays or heating may be used. As the resin, an ultraviolet curable resin, a thermosetting resin, or a dry photopolymer can be used, and a protective sheet that can be peeled off in a subsequent step can be formed on at least one of the resins. By forming the protective sheet, it becomes possible to apply pressure on the stamper via the resin and the protective sheet, and it is easy to obtain the sheet-like base material 30 having a uniform film thickness. Easy to carry and handle. In the present invention, a signal pattern forming method is not particularly limited as long as a predetermined signal pattern can be formed on a sheet-like substrate other than the method of forming a signal pattern on the sheet substrate.

  Moreover, the protective sheet which can be peeled on both surfaces or one side of a sheet-like base material can be formed as needed at each process. When each interlayer distance is short, it is necessary to make the sheet-like base material thin. Therefore, it is desirable not to form the resin layer on the sheet-like base material 30.

  The material of the sheet-like base material 30 and the signal pattern forming layer is not particularly limited as long as it is a material that does not optically interfere with recording / reproducing / erasing, but the wavelength of light used is not limited. The wavelength has been shortened to 785 nm for CD and 660 nm for DVD, and the wavelength of 405 nm is being studied for Blu-ray Disc. Therefore, a material that has low absorption and reflection in these wavelength ranges and low birefringence is desirable. . Specifically, polycarbonate resin, polyolefin resin, and acrylic resin are suitable as the sheet-like substrate and the thermoplastic sheet substrate for forming the signal pattern forming layer, but are not particularly limited. As materials for ultraviolet curable resins, thermosetting resins, and dry photopolymers, acrylic, epoxy, urethane, phenolic, and various modified materials can be used. It is desirable to use a material in which the absorption region of the photopolymerization initiator is different from the wavelength region of light used for recording / reproducing / erasing.

  The thickness of the sheet-like base material 30 may be an arbitrary film thickness, and is preferably about 1 μm to 300 μm. The thickness can be selected. Moreover, the thickness of the laminated sheet-like substrate 30 and the adhesive can be different in each layer, and an arbitrary interlayer distance can be formed with high accuracy by optimizing the thickness of the sheet. Can do.

  Moreover, the said sheet-like base material 30 can form the protective sheet which can be peeled in a post process on one or both surfaces, and can peel a protective sheet by arbitrary processes. The thickness of the protective sheet can be arbitrarily set, and it is possible to solve the problem in handling in the transporting and positioning process of the sheet-like substrate together with the protection of the sheet-like substrate. When the protective sheet is peeled off, static electricity is likely to be generated, and defects due to dust adhesion are likely to occur. Therefore, it is desirable to perform an antistatic process on the protective sheet or work in a static elimination environment.

  Furthermore, although it is considered preferable to use a roll of the sheet-like base material 30 from the viewpoint of productivity, it is not always necessary to roll up the roll, and it is not necessarily wound up into a roll, and is cut into each required size. It may be a sheet shape. The shape at that time may be any shape, such as a square shape or a round shape, or the presence or absence of an opening in the center hole, and is not particularly limited, but there is an area where the sheet can be appropriately held for position adjustment and conveyance. It is desirable to have a secured shape.

  Hereinafter, an example in which a thermoplastic resin is used as the sheet-like substrate 30 will be described.

  The sheet-like substrate 30 is conveyed to the forming device 32 by a conveying means 31 such as a roller. In FIG. 3, a roller is used as the conveying means, but it is sufficient that the required conveying accuracy is satisfied, and there is no particular limitation such as conveying by a belt conveyor system or an industrial robot. A signal pattern is transferred to the conveyed sheet base material 30 by a stamper 33 attached to a forming apparatus 32.

  The molding apparatus may be a press type that transfers the stamper shape by heating, pressing, or both. If necessary, the sheet base material can be peeled off from the stamper by cooling after the transfer step. The molding conditions such as temperature, pressure, moving distance, and cooling time are not particularly limited as long as optimum manufacturing conditions are selected depending on the signal pattern, transfer material, sheet thickness, and the like.

  The sheet-like base material 30 to which the signal pattern is transferred is subsequently conveyed to the film forming apparatus 35. In the film forming apparatus 35, a recording layer or a reflective layer is formed on the signal pattern forming surface by a method such as sputtering. Other deposition methods include vapor deposition, CVD, dipping coating, spin coating, and the like, and any method that is optimal for each production process, production apparatus, and recording medium to be produced is not particularly limited. Absent. As an optical recording film material, at least one kind of materials such as Te, In, Ga, Sb, Se, Pb, Ag, Au, As, Co, Ni, Mo, W, Pd, Ti, Bi, Zn, and Si are used. Alloys made of and the like are widely known in general, and many materials already exist as known techniques. In addition, alloys of at least one kind of materials such as Tb, Fe, Co, Cr, Gd, Dy, Nd, Sm, Ce, and Ho, and rare earth-transition metal alloys are often used as magneto-optical recording materials. Many of these materials already exist as known techniques. Al, Al alloys, Si, SiN, Ag, Ag alloys, and the like are also used as reflective film materials, and many materials already exist as known techniques. Furthermore, organic dye-based materials such as cyanine-based, phthalocyanine-based, and azo-based materials can be used as the recording layer. The film thickness of the recording layer or the reflective layer can be arbitrarily set, but light is attenuated in each recording layer and the reflective layer from the light incident surface side. Therefore, the transmittance at the wavelength of the light used is a layer close to the incident surface side. It is desirable that the recording layer and the reflective layer have a composition that does not hinder recording / reproducing / erasing by adjusting the composition and film thickness of each recording layer and reflecting layer. By optimizing the composition, film thickness, film forming conditions, and the like for each sheet base material and support substrate, a recording layer and a reflective layer having arbitrary transmittance and reflectance can be formed. In the present invention, there is no particular limitation by using a recording layer material suitable for the required optical recording medium.

  In addition, if a sheet-like base material that does not perform signal pattern formation and film formation is used, an intermediate layer or a support substrate for adjusting the interlayer distance can be obtained.

  Subsequently, the sheet-like base material on which the recording layer is formed is overlaid on the signal pattern. FIG. 5 schematically shows a superimposing step and a step of processing into an optical recording medium shape in the method for producing a multilayer-structured optical recording medium according to the present invention. A sheet-like base material 30 on which recording layers corresponding to the number of recording layers to be produced are formed is laminated on a multilayer sheet-like base material 51 that is adhered to a certain extent by a guide portion 50. At this time, the guide portion needs to work so as not to leave air between the sheets to be laminated. However, since the guide portion only needs to be in contact with a point with respect to the sheet being conveyed, There is no particular limitation. In the lamination of each recording layer and the support substrate, each layer may be temporarily fixed via an adhesive, or may be temporarily fixed by vacuum suction or electrostatic force without using an adhesive. FIG. 4 shows an application process required when using an adhesive. In the example shown in FIG. 4A, the sheet-like base material 30 is applied by passing through the inside of a tank 41 filled with the adhesive 40.

  Thereafter, the excess adhesive is removed by a doctor knife, a blade 42 or the like, and only the amount necessary for the subsequent film thickness is left, whereby the adhesive application process is completed. Also, as shown in FIG. 4 (B), the adhesive 40 is applied to the roller 43 in contact with the application surface, and the film thickness is controlled by the roller spacing and pressure, as shown in FIG. 4 (C). A method of dropping an adhesive onto a sheet-like substrate with a nozzle 44 or the like and then controlling the film thickness with a roller 43 is also a known technique, and is not particularly limited. Further, the adhesive may be applied on both sides of the sheet-like substrate or only on one side. Use a sheet-like adhesive layer sandwiched between protective sheets, or omit the adhesive application step using a sheet-like base material that has been previously coated with an adhesive or adhesive on the opposite side of the transfer layer. You can also. Examples of materials used as adhesives include cationic adhesives, thermosetting adhesives, two-part adhesives, UV adhesives, hot melts, pressure sensitive adhesives, etc., such as light transmittance and reflectance. There is no particular limitation as long as the specifications necessary for the optical recording medium are satisfied.

  After the lamination, the multilayer sheet-like substrate is collectively formed into an optical recording medium shape by the shape processing device 52. Thereafter, when an adhesive is used for temporarily fixing each layer, the adhesive 40 is cured. The curing step of the adhesive can also be performed before the shape processing step. In the process of stacking the sheets, in order to prevent air and foreign matter from entering, the sheets are stacked in a vacuum, or the multilayer sheets are sandwiched between flat plates from above and below in a vacuum or in the atmosphere, and pressed horizontally. Thus, it is desirable to cure the adhesive layer by making the distance between the layers uniform. Furthermore, it is more reliable and preferable to perform the shape processing in a state where the multilayer sheet is pressed horizontally from above and below in vacuum or in the air. In addition to the shape processing by a punching press, the shape processing can be performed by other methods such as shape processing by laser processing or cutting by mechanical cutting, and is not particularly limited.

  In the superposition and shape processing of the sheet-like base material, a support substrate having a recording layer or a reflective layer may be inserted, or a base material having no recording layer or a reflective layer may be inserted. The material used as the base material to be inserted is mainly a polycarbonate resin, a polyolefin resin, or a thermoplastic resin such as an acrylic resin, but is not particularly limited. The base material can be inserted in advance on the sheet base material, or after forming a multilayer sheet in which the sheet base material is laminated into an optical recording medium shape.

  The laminated recording medium 55 processed into the optical recording medium shape may be taken out from the shape processing apparatus 52 by handling means such as an arm (not shown), or may be advanced to the subsequent process by the conveying means in the same manner as other sheets. Good.

  The shape processing step by the shape processing device 52 needs to have a center alignment (hereinafter, centering) step for each recording layer. The alignment in the direction orthogonal to the sheet is roughly adjusted by passing through the guide portion 50, and further, precise alignment is performed by an alignment driving device built in the guide portion 50. Further, alignment of the sheet in the traveling direction is performed by tension rollers 54 provided before and after the guide portion for each sheet. In the present invention, it is performed by providing the guide part with a lamination and a rough position adjustment mechanism that gives a certain degree of adhesion, but by superposing the conveying means such as rollers close to each other, A method of adjusting the punching position by controlling the position of the roller is a known technique, and is not particularly limited.

  Position information for centering can be obtained by providing an alignment mark outside the information recording portion of each sheet and detecting it by a sensor 53 provided beside the punching device.

  The alignment mark is provided outside the effective area on the stamper 33, and can be transferred simultaneously when the signal pattern shape is transferred onto the sheet-like substrate by the molding device 32. However, since the mark must not be detected by film formation, the film formation area is larger than the effective area and smaller than the outer diameter of the optical recording medium shape, and the alignment mark is formed outside the area. Is preferably formed. Depending on the reading method, the alignment mark may be improved in reflectivity due to the film formation and may have high accuracy, and can be provided in an arbitrary region.

  FIG. 6 shows an example of alignment mark positions provided on the recording layer sheet. Here, the center position of the pattern is aligned by three alignment marks 62. The alignment mark shape can be read with high accuracy and the position can be adjusted. The shape of the alignment mark may not be a cross but may be a pattern with a slit in the cross or a star. In addition, a technique for determining the center position by measuring several outermost or innermost circumferences such as a signal pattern of the information recording unit is also known, and is not particularly limited.

  It is preferable to provide a plurality of alignment marks 62 outside the signal pattern area 61 or in a region to be cut after processing in order to improve the positional accuracy. However, even one alignment mark is possible, and one alignment mark is provided at the center of the substrate. It is also possible to provide an alignment mark and adjust the position so that each sheet coincides with the alignment mark. Further, in the above example, the position adjustment is performed after the sheet base materials are overlaid, but it is also possible to perform the alignment by performing the alignment before performing the superposition, and when using an adhesive that does not have fluidity. It is valid. Even when a roll-shaped sheet base material is not used, the outer peripheral portion that is cut when the position information of the sheet base material such as an alignment mark or a signal pattern is read and processed into an area outside the effective area or an optical recording medium shape as described above. The sheet base material can be aligned by finely adjusting the sheet traveling direction and the direction orthogonal thereto.

  Finally, a protective layer is formed on the entire surface of the laminated recording medium 55 to complete an optical recording medium having a multilayer structure. Hereinafter, a method of using a sheet or a film and a method of using a liquid resin will be described for protective layer formation.

  FIG. 8 is a process diagram for forming a protective layer with a resin sheet or film. Hereinafter, the protective layer forming step using a sheet or film will be described in detail with reference to FIG.

  (1) The laminated recording medium 55 is installed on the holding tool 81. As a holding method, a method of holding the inner peripheral side by a driving mechanism, a method of holding several points by point contact with a ball attached to a spring, and the like are conceivable, and there is no particular limitation.

  (2) Lay out with care so that air and foreign matter are not caught between the held laminated recording medium 55 and the protective layer sheet 80. In order to bring the protective layer sheet and the laminated recording medium into close contact with each other without involving air or foreign matter, this step is preferably performed in a vacuum. Various materials such as a thermoplastic resin and a heat-shrinkable resin can be considered as the material of the substrate-side protective layer sheet 80. Further, various materials can be used as long as they have an adhesive layer, and are not particularly limited. The protective layer sheet 80 may or may not be provided with a central hole in advance. Even if the sheet | seat 80 for protective layers is a sheet | seat of a sheet | seat form, considering productivity, it may be wound up in roll shape and is not specifically limited.

  (3) The protective layer sheet 80 and the laminated recording medium 55 are bonded together in close contact. What is necessary is just to perform as an adhesion | attachment method by the method according to the sheet | seat material for protective layers used. Further, on the inner peripheral side of the recording medium, it is desirable that the protective layer after adhesion protects the entire recording layer and does not protect a part of the support substrate. By doing so, the eccentricity accuracy is not impaired by clamping using a part of the support substrate that is not protected during signal reproduction.

  (4) The inner and outer peripheries are processed into an optical recording medium shape as necessary to complete a multilayer optical recording medium. This step is necessary when the central hole is not provided in the protective layer sheet. As a shape processing method, a punching method using a press machine or a laser processing method is known as a known technique, and is not particularly limited.

  FIG. 1 is a schematic cross-sectional view of a four-layer optical recording medium produced using a sheet in the protective layer forming step. The four-layer optical recording medium 113 produced by using a sheet in the protective layer forming step includes a sheet-like base material (102, 105, 108) on which a signal pattern is formed, and a signal pattern on the support substrate 111 on which the signal pattern is formed. A recording layer or a reflective layer (101, 104, 107, 110) is formed thereon, the sheet and the support substrate are laminated via an adhesive layer (103, 106, 109), and the laminate is a protective layer sheet. 100 is protected. In FIG. 8, 101 to 110 are simplified and shown as a laminated recording medium 55.

  FIG. 9 is a process diagram for forming a protective layer by dipping in a resin. Hereinafter, the protective layer forming step by applying a resin will be described in detail with reference to FIG.

  (1) The laminated recording medium 55 is installed on the holding tool 90. As described in the first embodiment of the invention, as the holding method, a method of holding the inner peripheral side by a drive mechanism, a method of holding several points by point contact with a ball attached to a spring, etc. are conceivable. There is no particular limitation.

  (2) The laminated recording medium 55 held in the tank 91 filled with the protective layer resin 20 is passed while rotating at a constant rotational speed. At this time, it is desirable that the resin does not contact the inner peripheral side wall. By doing so, the generation of burrs due to the effect of the protective layer resin can be prevented on the inner peripheral side, and the eccentricity accuracy is not impaired. The protective layer resin 20 may be an ultraviolet curable resin or the like, and is not particularly limited. However, a resin having sufficient hardness after curing is desirable because of its role as a protective layer.

  (3) After immersion, the film thickness of the protective layer resin 20 is controlled. As a method for controlling the film thickness, a method for controlling the rotation speed of the medium according to the viscosity of the resin for the protective layer to adjust the film thickness of the protective layer and a method for pulling up the immersed medium at a low speed are known techniques. It is not particularly limited.

  (4) The protective layer resin is cured by a method according to the material of the protective layer resin, such as ultraviolet irradiation or heating.

  (5) The multilayer optical recording medium is peeled from the holding tool 90 to complete the multilayer optical recording medium 21.

  FIG. 2 is a schematic cross-sectional view of a four-layer optical recording medium produced by dipping in a resin in the protective layer forming step. The four-layer optical recording medium 21 produced by applying a resin in the protective layer forming step includes a sheet-like base material (102, 105, 108) on which a signal pattern is formed, and a support substrate 111 on which the signal pattern is formed. A recording layer or a reflective layer (101, 104, 107, 110) is formed on the signal pattern, the sheet and the support substrate are laminated via an adhesive layer (103, 106, 109), and the laminate is a protective layer. The protective resin 20 is used for protection. In FIG. 9, 101 to 110 are simplified and shown as the laminated recording medium 55.

  Hereafter, the result implemented based on embodiment of this invention is shown.

Example 1
A four-layer optical recording medium was produced by a method of forming a protective layer using a sheet.

  FIG. 7 is a diagram showing a method of manufacturing a signal pattern forming stamper used in the present invention.

  In FIG. 7A, a photoresist 70 is applied to the master glass 71 by spin coating. (2) A predetermined signal pattern was exposed by the laser beam 72. (3) The exposed portion 73 was alkali-developed to form a signal pattern on the master glass 71. (4) A nickel conductive film 74 was formed on the surface of the signal pattern by sputtering. (5) Nickel electroforming was performed to form an electroformed layer 75. The thickness during electroforming was 0.3 mm, and the entire back surface was polished. (6) The nickel layer was peeled off from the original glass to produce a stamper 33 having a predetermined signal pattern.

  As described above, in the optical recording medium manufacturing method of the present invention, the conventionally used Ni stamper 33 that can be repeatedly used can be used, and a resin-made transparent stamper that is disposable for each molding can be used. There is no need to use it.

  3, 4, 5, 7, and 8 are diagrams showing a method of manufacturing a multilayer optical recording medium in which a protective layer is formed using the sheet according to the present invention.

  A polycarbonate resin sheet-like substrate 30 capable of transferring an uneven shape on one side is prepared. This sheet-like substrate 30 was provided with a thickness by forming a protective film having a thickness of 100 μm on one side so that it could be easily held and fixed. What prepared this sheet-like base material 30 on a roll was prepared. Three kinds of sheet-like base materials 108, 105, and 102 of 12, 13, and 14 μm were used as the thickness of the sheet-like base material. Thereby, the interlayer distance can be changed without changing the thickness of the adhesive, and the signal interference of each layer can be suppressed.

  The sheet-like substrate 30 is conveyed to a press mold forming device 32 by a roller 31 having a guide mechanism, and the conveyed sheet-like substrate 30 is heated and pressed by a die 34 to which a stamper 33 is attached. Then, the signal pattern shape was transferred.

  Next, the mold was cooled to lower the temperature of the sheet-like base material below the glass transition point and the heat distortion temperature, and then the mold was opened to separate the sheet-like base material from the stamper. The polycarbonate resin had a glass transition point of 140 ° C., a thermal deformation temperature of about 120 ° C., and the temperature of the sheet-like substrate when the mold was opened was about 30 to 40 ° C.

  In the signal pattern forming process, an alignment mark used in the subsequent stacking process was transferred. The alignment mark will be described in detail in the stacking process.

The sheet base material 30 to which the signal pattern shape was transferred was conveyed to the film forming apparatus 35. An Ag alloy film having a thickness of 10 nm was formed as a reflective layer on the signal pattern of the sheet base material by sputtering in the film forming apparatus 35. (107, 104, 101) At this time, a mask was used so that the alignment mark was hidden and no film was formed. The reflective layer on the support substrate 111 is L0 (110), the reflective layer on the sheet base material on L0 is L1 (107), the reflective layer on the sheet base material on L1 is on L2 (104), L2 When the reflective layer on the sheet base material was L3 (101), the transmittance of each reflective layer was in the following order.
L0 <L1 <L2 <L3
The transmittance was optimized without changing the film thickness depending on the film forming conditions such as film forming pressure, gas flow rate and power.

  Next, a bonding adhesive was applied to the sheet base material 30 on which the reflection layer was formed on the signal pattern shape. FIG. 4 shows a process of applying the adhesive 40 to the sheet base material 30 in the method for producing a multilayer structure optical recording medium according to the present invention. As shown in FIG. 4B, the adhesive 40 was applied to a roller 43 in contact with the application surface, and the film thickness was controlled by the roller spacing and pressure. The adhesive was applied to one side of the sheet base material without the signal pattern. A cationic adhesive was used as the adhesive, and the film thickness was 3 μm. (106, 103) The protective film was peeled off after the adhesive was applied.

  FIG. 5 schematically shows an overlaying step and a shape processing step in the method for producing a multilayer-structured optical recording medium according to the present invention. The punching method was adopted for shape processing. Hereinafter, in this embodiment, the shape processing apparatus is referred to as a punching apparatus. Three intermediate layer sheets were laminated in a state where they were in close contact with the guide portion 50 to some extent.

  Regarding the centering process in the punching process by the punching device 52, the alignment mark was detected by a sensor provided on the side of the punching device. FIG. 6 shows alignment marks 62 and positions provided outside the signal pattern area 61 of the recording layer sheet. In this embodiment, the center position of the pattern is adjusted by three alignment marks.

  The alignment in the direction orthogonal to the sheet was roughly adjusted by passing through the guide portion 50, and further, precise alignment was performed by an alignment driving device built in the guide portion 50. Further, the alignment of the traveling direction of the sheet was performed by the tension roller 54 provided before and after the guide portion for each sheet.

  After lamination, the multilayer sheet substrate was punched out at once by a punching device 52 to form an optical recording medium shape. After forming into an optical recording medium shape, it was taken out from the punching device 52 by handling means such as an arm (not shown). The multilayer sheet taken out is superimposed on the support substrate 111 on which the signal pattern is formed in advance and the reflective layer (L0) is formed on the pattern via the adhesive layer 109, and then the adhesive is cured, A four-layer laminated recording medium 55 was formed.

  FIG. 8 schematically shows a protective layer forming step when a sheet is used for forming the protective layer in the method for producing a multilayer optical recording medium according to the present invention.

  First, the laminated recording medium 55 was held by the holding tool 80. The protective layer sheet 100 was laid in a vacuum on the recording layer side of the held laminated recording medium 55 so that air and foreign matter were not caught between them. As the protective layer sheet, a sheet made of a thermoplastic resin and having a thickness of 75 μm was used. The protective layer sheet used is provided with a center hole whose inner and outer diameters completely cover the recording layer at the outer peripheral portion of the medium, and the outer diameter is 121 so that the inner peripheral portion does not protrude from the inner diameter of the support substrate 111 and become burr. The inner diameter was set to 14.0 mm.

  The whole was heated while the laminated recording medium 55 and the protective layer sheet were in close contact, and the protective layer sheet 100 and the laminated recording medium 55 were bonded. The heating temperature at the time of adhesion was 110 ° C.

  After the bonding, the medium was peeled off from the holding tool 80 to complete the four-layer optical recording medium 113 manufactured according to the first embodiment.

  FIG. 1 shows a schematic cross-sectional view of a four-layer optical recording medium 113 produced according to this example. A four-layer optical recording medium 113 manufactured according to the present example is formed by stacking and punching sheet-like base materials (102, 105, 108) on which signal patterns are formed via adhesive layers (103, 106). A recording layer or a reflective layer 110 is formed on the signal pattern of the support substrate 111 on which the pattern is formed, the laminated sheet is laminated on the support substrate 111 via an adhesive layer 109, and the laminate is used for a protective layer. The sheet 100 is completed by being protected.

  By forming a protective layer using a sheet according to this example, the film thickness could be controlled with high accuracy without impairing productivity. In addition, it is possible to provide a protective layer on the outer side of the recording medium where the reflective layer and recording layer are generally corroded by moisture absorption and easily peeled off, and have high durability against moisture absorption and hooking. I was able to. In addition, information was reproduced from the surface of the recording layer side protective layer sheet 84 of the completed multilayer optical recording medium 113 having a four-layer structure, but reproduction was possible without problems in each layer.

(Example 2)
A four-layer optical recording medium was produced by a method of forming a protective layer by dipping in a resin.

  In the same manner as in Example 1, a post-shape processing recording medium 55 was produced. The formation of the protective layer will be described in detail below.

  FIG. 9 schematically shows a process for forming a protective layer by dipping in a resin in the method for producing a multilayer optical recording medium according to the present invention.

  The laminated recording medium 55 was held on the holding tool 90.

  The held laminated recording medium 55 was rotated and passed through a tank 91 filled with the protective layer resin 20. An ultraviolet curable resin (Nippon Kayaku INC-118) was used as the protective layer resin, and the number of revolutions during immersion was 60 rpm, and the immersion time was 2.0 seconds. Further, as shown in FIG. 9 (2), only the radius from 8.0 mm to the outermost periphery was immersed so that the inner peripheral side of the medium was not immersed in the protective layer resin.

  The film thickness of the protective layer resin 20 was controlled by spinning the immersed medium. The spin rotation speed was 1250 rpm, and the thickness of the protective layer was controlled to 75 μm.

  After adjusting the film thickness, the protective layer resin 92 was cured by irradiating ultraviolet rays, and was peeled off from the holding tool 90 to complete the four-layer optical recording medium 21 produced according to the second embodiment.

  FIG. 2 is a schematic cross-sectional view of a four-layer optical recording medium manufactured according to this example. The four-layer optical recording medium 21 manufactured according to the present example is obtained by stacking and punching sheet-like base materials (102, 105, 108) on which signal patterns are formed via adhesive layers (103, 106). A recording layer or a reflective layer 110 is formed on the signal pattern of the support substrate 111 on which the pattern is formed, the laminated sheet is laminated on the support substrate 111 via an adhesive layer 109, and the laminate is used for a protective layer. It is completed by being protected by the resin 20.

  By forming the protective layer by immersing in a liquid resin according to the present embodiment, the reflection film and the recording film are generally corroded due to moisture absorption, and the outer periphery of the recording medium where peeling due to the hook is likely to occur is seamless. A protective coat could be formed, and durability could be improved. In the manufacturing process, bubbles and foreign matters could be easily removed without forming a protective layer in a vacuum. In addition, the resin for the protective layer that has been shaken off by spinning or the like can be further reused, and there was no waste of the resin for the protective layer, and by immersing multiple pieces in the resin together, cost reduction and productivity were reduced. The improvement was realized.

  Information was reproduced from the recording layer side of the completed multilayer optical recording medium having a four-layer structure, but reproduction was possible in each layer without any problem.

Schematic sectional view of a multilayer optical recording medium in which a protective layer is formed using a sheet according to the present invention FIG. 2 is a schematic cross-sectional view of a multilayer optical recording medium in which a protective layer is formed by dipping in a resin according to the present invention. Schematic diagram of a process for forming a signal pattern and a recording layer or a reflective layer on a sheet-like substrate according to the present invention Schematic diagram of the process of applying an adhesive to the sheet-like substrate according to the present invention Schematic diagram of the process of superposing a plurality of sheet-like substrates according to the present invention and the shape processing process An example of alignment mark arrangement according to the present invention Schematic diagram of stamper manufacturing process Schematic diagram of the process of forming a protective layer with a sheet or film Schematic diagram of the process of forming a protective layer by immersing in resin

Explanation of symbols

100 Protective layer sheet 101 Recording layer or reflective layer (L3)
102 Sheet-like base material on which signal pattern is formed 103 Adhesive layer 110 Recording layer or reflective layer (L0)
DESCRIPTION OF SYMBOLS 111 Support substrate in which signal pattern was formed 20 Resin for protective layers 30 Sheet-like base material 40 Adhesive 41 Adhesive application tank 51 Multi-layered sheet-like base material 52 Punching device 55 Multilayer recording medium

Claims (4)

Forming a recording layer and a reflective layer having a concavo-convex pattern on the surface of the sheet-like substrate;
A step of superposing a plurality of the sheet-like base materials on which the recording layer is formed in a state of being positioned with respect to each other; a step of collectively processing the plurality of sheet-like base materials superposed on each other;
A method for producing an optical recording medium, comprising a step of forming a protective layer on side surfaces of the plurality of processed sheet-like substrates.   2. The method of manufacturing an optical recording medium according to claim 1, wherein in the protective layer forming step, the protective layer is formed using a resin sheet or film.   2. The method of manufacturing an optical recording medium according to claim 1, wherein the protective layer is formed of a liquid resin in the protective layer forming step. An optical recording medium manufactured by the manufacturing method according to claim 1.

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