WO2010116945A1 - Multilayer optical information recording medium - Google Patents

Multilayer optical information recording medium Download PDF

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Publication number
WO2010116945A1
WO2010116945A1 PCT/JP2010/056000 JP2010056000W WO2010116945A1 WO 2010116945 A1 WO2010116945 A1 WO 2010116945A1 JP 2010056000 W JP2010056000 W JP 2010056000W WO 2010116945 A1 WO2010116945 A1 WO 2010116945A1
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WO
WIPO (PCT)
Prior art keywords
layer
information recording
intermediate layer
recording medium
substrate
Prior art date
Application number
PCT/JP2010/056000
Other languages
French (fr)
Japanese (ja)
Inventor
圭介 米田
真一 小城
淳 赤羽
将志 服部
宏樹 石原
Original Assignee
太陽誘電株式会社
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Publication of WO2010116945A1 publication Critical patent/WO2010116945A1/en

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/007—Arrangement of the information on the record carrier, e.g. form of tracks, actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/2403—Layers; Shape, structure or physical properties thereof
    • G11B7/24035—Recording layers
    • G11B7/24038—Multiple laminated recording layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
    • G11B7/263—Preparing and using a stamper, e.g. pressing or injection molding substrates
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
    • G11B7/266—Sputtering or spin-coating layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/244—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only
    • G11B7/246—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only containing dyes
    • G11B7/2467—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only containing dyes azo-dyes
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/244—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only
    • G11B7/246—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only containing dyes
    • G11B7/247—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only containing dyes methine or polymethine dyes
    • G11B7/2472—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only containing dyes methine or polymethine dyes cyanine
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
    • G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
    • G11B7/2531—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising glass
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
    • G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
    • G11B7/2532—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising metals
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/252—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
    • G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
    • G11B7/2533—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising resins

Definitions

  • the present invention relates to a multilayer optical information recording medium having a plurality of information recording layers.
  • an optical information recording medium such as an optical disk has become widespread.
  • an optical information recording medium there is one in which an information recording layer is formed on a light-transmitting resin substrate having a thickness of 1.2 mm and a diameter of 120 mm or 80 mm, such as a compact disc (CD).
  • a compact disc CD
  • an optical information recording medium such as a DVD using an objective lens having a short laser wavelength and a large numerical aperture (NA) has been realized.
  • This DVD has a structure in which two light-transmissive resin substrates having a thickness of 0.6 mm are bonded together and an information recording layer is sandwiched between the substrates.
  • BD Blu-ray Disc is a registered trademark.
  • This BD has a structure in which an information recording layer is formed on the light incident surface side of a resin substrate having a thickness of 1.1 mm, and a light transmission layer having a thickness of 0.1 mm is provided on the surface on which the information recording layer is formed. have.
  • optical discs include write-once type optical discs.
  • a reflective layer formed on pits arranged in a spiral or concentric pattern on a substrate serves as an information recording layer.
  • an information recording layer is composed of a light absorption layer and a reflection layer formed on a guide groove arranged in a spiral or concentric pattern on a substrate.
  • organic dyes such as cyanine dyes and azo dyes, and inorganic materials such as Si, Cu, Sb, Te, and Ge are used.
  • data is recorded by irradiating a light-absorbing layer on the guide groove with a recording laser beam to form pits.
  • BD is standardized so that a recording capacity of 100 gigabytes can be realized with a maximum of four information recording layers.
  • a light-transmitting intermediate layer having a thickness of 25 ⁇ m is provided on a first information recording layer formed on a 1.1 mm-thick substrate, and a second information recording layer is provided thereon.
  • a light transmission layer is formed.
  • the thickness of the light transmission layer is 75 ⁇ m when the recording layer is two layers, 50 ⁇ m when the recording layer is three layers, and 25 ⁇ m when the recording layer is four layers.
  • Such a multilayer optical disc is formed by the following process as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-048367.
  • a substrate 2 on which a first information recording layer is formed is prepared. This substrate is formed by a single-layer optical disc manufacturing process.
  • a resin or metal stamper having a protrusion for forming a spiral or concentric guide groove is prepared, and light is applied to the surface of the stamper having a protrusion by spin coating or the like.
  • a transparent curable resin is applied and cured to form the intermediate layer 5.
  • an adhesive layer such as an ultraviolet curable adhesive is formed on the intermediate layer 5 and the first information recording layer 3 of the previously prepared substrate 2 by spin coating or the like.
  • 4a and an adhesive layer 4b are formed and bonded together.
  • the stamper is peeled off as shown in FIG.
  • a second information recording layer is formed on the intermediate layer 5, and then a light-transmitting curable resin is applied by spin coating or the like, or a light-transmitting curable resin is applied.
  • seat is affixed and a light transmissive layer is formed.
  • a photopolymer method hereinafter referred to as 2P method. *
  • Such a 2P method is costly in that it requires a stamper for forming the intermediate layer and requires a stamper peeling process, but a multilayer optical disk having good recording characteristics can be obtained. For this reason, the 2P method is preferably used for manufacturing a multilayer optical disk.
  • the adhesive 4 b is applied without peeling the stamper from the intermediate layer 5 as shown in FIG. 15.
  • meandering may occur on the inner peripheral edge side (left side in FIG. 15) of the intermediate layer due to variations in the application of the adhesive. This meandering may impair the appearance of the product.
  • the adhesive 4 b may be applied so as to protrude beyond the edge of the intermediate layer 5. If the adhesive 4b is cured in this state, the stamper is adhered and is difficult to peel off. As a result, a large stress is applied when the stamper is peeled off, and the intermediate layer 5 is often cracked or chipped. *
  • the adhesive layer 4 has a role of adjusting the thickness
  • the combined thickness of the intermediate layer 5 and the adhesive layer 4 becomes a predetermined thickness. Paste together.
  • excess adhesive may protrude from the inner peripheral edge of the intermediate layer 5.
  • the stamper is adhered and is difficult to peel off.
  • the intermediate layer 5 may be cracked or chipped as shown in FIG.
  • the protruding adhesive causes meandering at the inner peripheral edge of the intermediate layer 5, and this meandering may impair the appearance of the product.
  • a disk-shaped substrate having concave portions arranged in a spiral or concentric shape on one surface, a first information recording layer formed on one surface of the substrate, and the first information
  • An intermediate layer formed on one surface with concave portions formed on the recording layer and arranged in a spiral or concentric circle; and a second information recording layer formed on one surface of the intermediate layer
  • a multilayer optical information recording medium is proposed in which concentric grooves are formed continuously or intermittently in the vicinity of the inner periphery of the intermediate layer.
  • the concentric grooves prevent the adhesive from protruding, deterioration of the appearance of the product can be reduced. Moreover, since it can suppress that a stamper adhere
  • a radius of 10.5 to 12.5 mm from the center of the multilayer optical information recording medium is a suitable range.
  • a position having a radius of 10.5 mm from the center of the multilayer optical information recording medium corresponds to the inner peripheral edge of the intermediate layer. That is, it is preferable that concentric grooves are formed within a range of 2.0 mm from the inner peripheral edge of the intermediate layer toward the outer periphery.
  • FIG. 1 is a plan view schematically showing a multilayer optical information recording medium of the present invention.
  • FIG. 2 is a diagram schematically showing a cross section taken along the line AA of FIG. 1 and showing the first embodiment of the present invention. It is a figure which shows the manufacturing process of the multilayer type
  • FIG. 1 It is a figure which shows the manufacturing process of the multilayer type
  • FIG. 3 is a diagram schematically showing a cross section taken along line AA of FIG. 1, and is a diagram showing a second embodiment of the present invention.
  • FIG. 6 is a diagram schematically showing a cross section taken along line AA in FIG. 1, and showing a third embodiment of the present invention.
  • mold optical information recording medium It is a figure which shows the manufacturing process of the conventional multilayer type
  • mold optical information recording medium It is a figure which shows the problem of the conventional multilayer type
  • FIG. 1 is a plan view of a multilayer optical disc according to the present invention
  • FIG. 2 is a partial cross-sectional view taken along the line AA in FIG.
  • Concentric grooves 7 are intermittently formed in the vicinity of the inner peripheral edge of the intermediate layer 5.
  • the vicinity of the inner peripheral edge of the intermediate layer 5 is a range in which the effect of the present invention is exerted in the clamping area, from the inner peripheral edge of the intermediate layer located at a radius of 10.5 mm from the center of the disk to the outer periphery.
  • a range of 2.0 mm toward the disk, that is, a radius of 10.5 mm to 12.5 mm from the center of the disk is particularly preferable.
  • the multilayer optical disc 1 'in FIG. 2 has the following configuration.
  • a spiral or concentric guide groove GV1 is provided with a disk-shaped substrate 2 formed on one surface.
  • a first information recording layer 3 is formed on one surface of the substrate 2.
  • an intermediate layer 5 having a spiral or concentric guide groove GV2 on one surface is formed via an adhesive layer 4.
  • a second information recording layer 6 is formed on the intermediate layer 5.
  • a light transmission layer 8 is formed on the second information recording layer 6.
  • the first information recording layer 3 includes a reflective layer 3a formed on one surface of the substrate 2, a light absorbing layer 3b formed on the reflective layer 3a, and a protective layer formed on the light absorbing layer 3b. 3c.
  • the second information recording layer 3 includes a reflective layer 6a formed on the intermediate layer 5, a light absorbing layer 6b formed on the reflective layer 6a, and a protective layer 6c formed on the light absorbing layer 6b. And is composed of.
  • a concentric groove 7 is formed near the inner periphery of the intermediate layer 5.
  • the substrate 2 is a disc-shaped substrate having a thickness of 1.1 mm and a diameter of 120 mm.
  • Various materials used as the substrate material of the conventional optical disc can be arbitrarily selected and used for the substrate 2.
  • Specific examples include acrylic resins such as polycarbonate and polymethyl methacrylate, vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers, epoxy resins, amorphous polyolefins, polyester resins, metals such as aluminum, and glass. If necessary, these may be used in combination or by a method such as mixing.
  • a thermoplastic resin is preferable from the viewpoint of moldability, moisture resistance, dimensional stability, and low price, and polycarbonate is particularly preferable.
  • Such a substrate 2 is formed by injection molding.
  • a stamper is set in the mold, whereby a spiral or concentric guide groove GV1 is formed in the substrate 2.
  • the guide groove GV1 is formed with a pitch of 0.32 ⁇ m to 0.35 ⁇ m, and pits are formed in the guide groove GV1.
  • the reflective layer 3a of the first information recording layer 3 is formed of a metal thin film having a high reflectance such as an Ag alloy or an Al alloy, and is formed by sputtering or the like. Since the reflection layer 3a may totally reflect the incident light, the thickness is preferably 55 nm to 65 nm.
  • the light absorption layer 3b includes one using an organic dye and one using an inorganic material. In the case of the light absorption layer 3b using an organic dye, it is formed by applying a solution obtained by dissolving an organic dye such as a cyanine dye or an azo dye in a solvent such as TFP by a spin coating method.
  • the dye used for the light absorption layer 3b has a characteristic of being decomposed by absorbing laser light having a wavelength of 405 nm.
  • an inorganic material for example, a phase change type such as Te—Pd, an alloy type in which a Si film and a Cu alloy film are laminated, or a decomposition reaction in which Bi—N and Ge—N are mixed. A type is mentioned.
  • These inorganic material-based light absorption layers 3b are formed by sputtering.
  • the protective layer 3c is a solvent of a curable resin that becomes the intermediate layer 5 and the diffusion of the dye contained in the light absorption layer 3b when the intermediate layer 5 is formed. This is to prevent a mixing phenomenon such as penetration into the light absorption layer 3b.
  • the material constituting the protective layer 3c is silicon oxide, particularly silicon dioxide, oxides such as zinc oxide, cerium oxide, yttrium oxide; sulfides such as zinc sulfide and yttrium sulfide; nitrides such as silicon nitride; silicon carbide; Examples thereof include a mixture of an oxide and a sulfur compound.
  • the same layer as the protective layer 3c is formed as a dielectric film for improving light absorption.
  • the protective layer 3c is formed by a method such as sputtering.
  • the reflective layer 3a, the light absorbing layer 3b, and the protective layer 3c constitute the first information recording layer 3.
  • the intermediate layer 5 is formed by a method in which a liquid curable resin is applied on a resinous or metallic stamper by a spin coating method or the like and cured, and is bonded to the substrate 2 via the adhesive layer 4.
  • a liquid curable resin for example, an ultraviolet curable resin such as trade name: SD-694 (manufactured by DIC Corporation) is suitably used.
  • spiral or concentric guide grooves GV2 are formed with a pitch of 0.32 ⁇ m to 0.35 ⁇ m.
  • the reflective layer 6a of the second information recording layer 6 is formed of a metal thin film having high reflectivity such as Ag alloy or Al alloy, and is formed by sputtering or the like. Since the reflective layer 6a of the second information recording layer 6 may reflect or transmit incident light, it needs to be semi-transmissive. Therefore, a metal film that is thinner than the reflective layer 3a of the first information recording layer 3 is preferable, and preferably 20 nm to 30 nm.
  • the light absorption layer 6b and the protective layer 6c are substantially the same as the light absorption layer 3b and the protective layer 3c of the first information recording layer 3.
  • the semi-transmissive reflective layer 6a, the light absorbing layer 6b, and the protective layer 6c constitute a second information recording layer 6.
  • the light transmissive layer 8 is formed of a light transmissive resin.
  • a curable resin that is cured by ultraviolet rays or radiation is formed by a spin coating method or the like, or a resin sheet that is cured by ultraviolet rays or radiation is formed by using a transparent adhesive. To be formed.
  • the light transmittance of the light-transmitting layer 8 is not less than 70%, preferably not less than 80% when measured with a spectrophotometer with a light having a wavelength of 405 nm with a thickness of 0.1 mm after curing. Since the light transmission layer 8 is relatively soft and easily damaged, a hard coat layer (not shown) made of an acrylic resin or the like may be provided on the surface on the light incident side.
  • a substrate 2 on which a first information recording layer 3 is formed is prepared. This is formed by the normal process of a single layer optical disc.
  • the substrate 2 is taken out from the mold, and an Ag alloy film is formed on the surface having the guide groove GV1 by sputtering to form the reflective layer 3a.
  • a solution obtained by dissolving an organic dye in a solvent such as TFP is applied onto the reflective layer 3a by spin coating, and dried to form the light absorption layer 3b.
  • the protective layer 3c is formed by sputtering.
  • a resin stamper for forming the guide groove GV2 in the intermediate layer 5 is prepared.
  • Polycarbonate or ZEONOR (trade name: manufactured by Nippon Zeon Co., Ltd.) is injected by an injection molding machine into a mold in which an original Ni stamper is set, and a resin stamper having protrusions that are reverse patterns of guide grooves is formed.
  • a resin stamper is taken out from the mold, and a curable resin is applied to the stamper to a thickness of 20 ⁇ m, for example, by spin coating. Thereafter, the curable resin is cured to form the intermediate layer 5.
  • a cut 7 is formed in the vicinity of the inner peripheral edge of the intermediate layer 5.
  • the resin near the inner peripheral edge of the intermediate layer 5 is rotated while rotating the stamper on which the intermediate layer 5 is formed or rotating the removing means.
  • the removing means include a carbon dioxide gas laser and a YAG laser in addition to a cutter and a pin. In this way, the cuts 7 are formed in the intermediate layer 5 as shown in FIG.
  • an adhesive is applied on the intermediate layer 5.
  • a light transmissive curable resin is preferably used, and examples thereof include an acrylic ultraviolet curable resin.
  • the same UV curable resin used for forming the intermediate layer 5 may be used.
  • the intermediate layer 5 on the stamper is bonded onto the first information recording layer 3 of the substrate 2 prepared in advance.
  • the adhesive layer 4a is also formed on the substrate 2 side, and the adhesive layers are bonded together. Since the adhesive layer has a role of adjusting the thickness, the adhesive layer is bonded so that the total thickness of the intermediate layer 5 and the adhesive layer is a predetermined thickness, for example, 25 ⁇ m.
  • the adhesive layer 4 is cured, and then the stamper is peeled off.
  • the second information recording layer 6 is formed on the surface of the intermediate layer 5 where the guide groove GV2 is formed.
  • a light transmission layer 8 having a thickness of 75 ⁇ m is formed on the second information recording layer 6 to obtain a multilayer optical disc 1 ′ shown in FIG. 2.
  • the adhesive When the adhesive is inserted into the notch 7, as shown in FIG. 10, the adhesive may enter the notch 7 so that the adhesive adheres to the stamper. This part becomes a part where the concentric grooves are interrupted. In such a portion, the adhesive adheres to the stamper, but since the ratio is small, the intermediate layer 5 is not cracked or chipped. If a space is formed in the entire cut 7, the concentric grooves are continuous concentric circles.
  • the multilayer optical disk 11 in FIG. 11 shows a case of DVD ⁇ R, and has the following configuration.
  • a spiral or concentric guide groove GV11 has a disk-like substrate 12 formed on one surface.
  • a first information recording layer 13 is formed on one surface of the substrate 12.
  • An intermediate layer 15 having a spiral or concentric guide groove GV12 on one surface is formed on the first information recording layer 13 via an adhesive layer 14a.
  • a second information recording layer 16 is formed on the intermediate layer 15.
  • a dummy substrate 18 is formed on the second information recording layer 16 through an adhesive layer 14b.
  • the first information recording layer 13 includes a light absorption layer 13b formed on one surface of the substrate 12, and a semi-transmissive reflection layer 13a formed on the light absorption layer 13b. Yes.
  • the second information recording layer 16 is composed of a light absorption layer 16b formed on one surface of the intermediate layer 15 and a reflection layer 16a formed on the light absorption layer 16b.
  • the multilayer optical disk 11 shown in FIG. 3 is that the substrate 12 is necessarily light transmissive, the thickness of the substrate 2 is 0.6 mm, the positions of the reflection layer 13a and the light absorption layer 13b with respect to the substrate 2, and the intermediate layer. 15, the positions of the reflective layer 16a and the light absorbing layer 16b are reversed, the pitch of the guide groove GV11 and the guide groove GV12 is 0.74 ⁇ m, and the wavelength of the laser light used for recording and reproduction is 650 nm Except for this point, the configuration is substantially the same as the multilayer optical disc 1 ′ of the first embodiment. As for the manufacturing process, the formation of the intermediate layer that is the main part of the present invention is the same as in the first embodiment.
  • the multilayer optical disk 21 of FIG. 12 shows a case of a BD-ROM, and has the following configuration.
  • a pit PT1 arranged in a spiral or concentric manner has a disk-like substrate 22 formed on one surface.
  • a first information recording layer 23 is formed on one surface of the substrate 22.
  • an intermediate layer 25 having pits PT2 arranged spirally or concentrically on one surface is formed via an adhesive layer 24.
  • a second information recording layer 26 is formed on one surface of the intermediate layer 25.
  • a light transmission layer 28 is formed on the second information recording layer 26. Since the multilayer optical disk 22 shown in FIG. 12 is read-only, the first information recording layer 23 is composed only of a total reflection metal film.
  • the second information recording layer 26 is composed only of a transflective metal film.
  • the multilayer optical disk 21 shown in FIG. 12 has a point that pit rows are formed on the substrate 22 and the intermediate layer 25, and a point that no light absorption layer exists in the first information recording layer 23 and the second information recording layer 26.
  • the configuration is substantially the same as that of the multilayer optical disc 1 ′ of the first embodiment.
  • the formation of the intermediate layer that is the main part of the present invention is the same as in the first embodiment.
  • Multi-layer type optical disc 2 12, 22 Substrate 3, 13, 23 First information recording layer 3a, 13a, reflective layer 3b, 13b light absorbing layer 3c protective layer 4, 14, 24 adhesive layer 5, 15, 25 intermediate layer 6, 16, 26 second information Recording layer 6a, 16a, reflective layer 6b, 16b light absorption layer 6c protective layer 7, 17, 27 concentric grooves (notches) 8, 28 Light transmission layer 18, dummy substrate

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  • Manufacturing & Machinery (AREA)
  • Optical Record Carriers And Manufacture Thereof (AREA)

Abstract

Provided is a multilayer optical information recording medium which has an excellent appearance and few defects such as fractures, chips, or the like in an intermediate layer. The multilayer optical information recording medium comprises a disc-like substrate having recessed portions arranged concentrically or helically in one surface thereof, a first information recording layer formed on the one surface of the substrate, an intermediate layer which is formed on the first information recording layer and has recessed portions arranged concentrically or helically in one surface thereof, and a second information recording layer formed on the one surface of the intermediate layer. In the multilayer optical information recording medium, concentric trenches are formed continuously or intermittently near the inner peripheral edge of the intermediate layer.

Description

多層型光情報記録媒体Multi-layer optical information recording medium
　本発明は、複数層の情報記録層を有する多層型光情報記録媒体に関するものである。 The present invention relates to a multilayer optical information recording medium having a plurality of information recording layers.
　情報記録媒体として、光ディスクのような光情報記録媒体が普及してきている。このような光情報記録媒体としては、コンパクトディスク（ＣＤ）のような、厚さ１．２ｍｍ、直径１２０ｍｍまたは８０ｍｍの光透過性の樹脂基板上に情報記録層を形成したものがある。そしてさらに高い情報記録密度を実現するため、レーザ波長を短く且つ開口数（ＮＡ：ｎｕｍｅｒｉｃａｌ　ａｐｅｒｔｕｒｅ）の大きな対物レンズを使用するＤＶＤのような光情報記録媒体が実現されている。このＤＶＤは、厚さ０．６ｍｍの光透過性の樹脂基板を２枚貼り合せ、この基板間に情報記録層を挟んだ構造を有している。 As an information recording medium, an optical information recording medium such as an optical disk has become widespread. As such an optical information recording medium, there is one in which an information recording layer is formed on a light-transmitting resin substrate having a thickness of 1.2 mm and a diameter of 120 mm or 80 mm, such as a compact disc (CD). In order to realize a higher information recording density, an optical information recording medium such as a DVD using an objective lens having a short laser wavelength and a large numerical aperture (NA) has been realized. This DVD has a structure in which two light-transmissive resin substrates having a thickness of 0.6 mm are bonded together and an information recording layer is sandwiched between the substrates.
　そして近年では、高精細な映像データを記録するために、さらに高い情報記録密度が要求されてきている。そこで、ブルーレイディスク（ＢＤ：ブルーレイディスクは登録商標）のように、より波長の短い青紫レーザ光を用いる光ディスクが実現されている。このＢＤは、厚さ１．１ｍｍの樹脂基板の光入射面側に情報記録層が形成され、この情報記録層が形成された面上に厚さ０．１ｍｍの光透過層が設けられた構造を有している。 In recent years, higher information recording density has been required to record high-definition video data. Therefore, an optical disc using a blue-violet laser beam having a shorter wavelength has been realized, such as a Blu-ray disc (BD: Blu-ray Disc is a registered trademark). This BD has a structure in which an information recording layer is formed on the light incident surface side of a resin substrate having a thickness of 1.1 mm, and a light transmission layer having a thickness of 0.1 mm is provided on the surface on which the information recording layer is formed. have.
そして、これらの光ディスクには、追記型の光ディスクがある。読み出し専用の光ディスクは、基板上の螺旋状または同心円状に並んだピット上に形成された反射層が情報記録層となる。一方、追記型の光ディスクは、基板上の螺旋状または同心円状に並んだ案内溝上に形成された光吸収層と反射層とで情報記録層が構成されている。光吸収層としては、シアニン系色素やアゾ系色素等の有機色素や、Ｓｉ、Ｃｕ、Ｓｂ、Ｔｅ、Ｇｅ等の無機材料が用いられる。追記型の光ディスクは、案内溝上の光吸収層に記録用レーザ光を照射して、ピットを形成することによってデータが記録される。 These optical discs include write-once type optical discs. In a read-only optical disc, a reflective layer formed on pits arranged in a spiral or concentric pattern on a substrate serves as an information recording layer. On the other hand, in a write-once optical disc, an information recording layer is composed of a light absorption layer and a reflection layer formed on a guide groove arranged in a spiral or concentric pattern on a substrate. As the light absorption layer, organic dyes such as cyanine dyes and azo dyes, and inorganic materials such as Si, Cu, Sb, Te, and Ge are used. In a write-once optical disc, data is recorded by irradiating a light-absorbing layer on the guide groove with a recording laser beam to form pits.
しかし、このように情報記録密度を高くした光ディスクにも、記録容量のさらなる大容量化が要求されてきている。そこで情報記録層を２層以上設けた多層型の光ディスクが提案されてきている。特にＢＤは最大４層の情報記録層で１００ギガバイトの記録容量を実現できるように規格化がなされている。このような多層型光ディスクは、１．１ｍｍ厚の基板上に形成された第一の情報記録層上に、厚さ２５μｍの光透過性の中間層を設け、その上に第二の情報記録層を形成し、最後に光透過層を形成した構造を有する。光透過層の厚さは、記録層が２層の場合は７５μｍ、３層の場合は５０μｍ、４層の場合は２５μｍとなる。　 However, there is a demand for a further increase in recording capacity even for an optical disc having such a high information recording density. Therefore, a multilayer type optical disc having two or more information recording layers has been proposed. In particular, BD is standardized so that a recording capacity of 100 gigabytes can be realized with a maximum of four information recording layers. In such a multilayer optical disc, a light-transmitting intermediate layer having a thickness of 25 μm is provided on a first information recording layer formed on a 1.1 mm-thick substrate, and a second information recording layer is provided thereon. And finally a light transmission layer is formed. The thickness of the light transmission layer is 75 μm when the recording layer is two layers, 50 μm when the recording layer is three layers, and 25 μm when the recording layer is four layers. *
このような多層型光ディスクは例えば特開２００７－０４８３６７号公報に開示されているように、次のようなプロセスで形成される。まず、図１３に示すように、第一の情報記録層が形成された基板２を用意する。この基板は単層の光ディスクの製造プロセスによって形成される。次いで図１４に示すように、螺旋状または同心円状の案内溝を形成するための突起を有する樹脂製または金属製のスタンパを用意し、このスタンパの突起のある面上にスピンコート法等によって光透過性の硬化性樹脂を塗布して硬化させ、中間層５を形成する。次いで図１５～図１７に示すように、この中間層５と、先に用意した基板２の第一の情報記録層３上とに、スピンコート法等によって紫外線硬化性接着剤等の接着剤層４ａおよび接着剤層４ｂを形成し、互いを貼りあわせる。接着剤層４を硬化させた後、図１８に示すように、スタンパを剥離する。その後、図示していないが、中間層５上に第二の情報記録層を形成し、次いで、スピンコート法等によって光透過性の硬化性樹脂を塗布するか、または光透過性の硬化性樹脂シートを貼り付けて、光透過層を形成する。このような中間層５を有する多層型光ディスクの形成方法は、フォトポリマー法（以下２Ｐ法）と呼ばれるものである。　 Such a multilayer optical disc is formed by the following process as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-048367. First, as shown in FIG. 13, a substrate 2 on which a first information recording layer is formed is prepared. This substrate is formed by a single-layer optical disc manufacturing process. Next, as shown in FIG. 14, a resin or metal stamper having a protrusion for forming a spiral or concentric guide groove is prepared, and light is applied to the surface of the stamper having a protrusion by spin coating or the like. A transparent curable resin is applied and cured to form the intermediate layer 5. Next, as shown in FIGS. 15 to 17, an adhesive layer such as an ultraviolet curable adhesive is formed on the intermediate layer 5 and the first information recording layer 3 of the previously prepared substrate 2 by spin coating or the like. 4a and an adhesive layer 4b are formed and bonded together. After the adhesive layer 4 is cured, the stamper is peeled off as shown in FIG. Thereafter, although not shown, a second information recording layer is formed on the intermediate layer 5, and then a light-transmitting curable resin is applied by spin coating or the like, or a light-transmitting curable resin is applied. A sheet | seat is affixed and a light transmissive layer is formed. Such a method for forming a multilayer optical disc having the intermediate layer 5 is called a photopolymer method (hereinafter referred to as 2P method). *
このような２Ｐ法は、中間層を形成するためのスタンパが必要な点や、スタンパの剥離工程が必要な点でコスト高になるが、良好な記録特性を有する多層型光ディスクが得られる。そのため、多層型光ディスクの製造には２Ｐ法が好適に用いられる。 Such a 2P method is costly in that it requires a stamper for forming the intermediate layer and requires a stamper peeling process, but a multilayer optical disk having good recording characteristics can be obtained. For this reason, the 2P method is preferably used for manufacturing a multilayer optical disk.
特開２００７－０４８３６７号公報JP 2007-048367 A
ここで２Ｐ法においては、中間層５に硬化性接着剤を塗布するとき、図１５に示すように、中間層５からスタンパを剥離しない状態で接着剤４ｂの塗布が行われる。この場合図１５に示すように、中間層の内周縁側（図１５の左側）において、接着剤の塗布ばらつきにより蛇行が生じることがある。この蛇行により、製品の外観が損なわれることがある。　 Here, in the 2P method, when the curable adhesive is applied to the intermediate layer 5, the adhesive 4 b is applied without peeling the stamper from the intermediate layer 5 as shown in FIG. 15. In this case, as shown in FIG. 15, meandering may occur on the inner peripheral edge side (left side in FIG. 15) of the intermediate layer due to variations in the application of the adhesive. This meandering may impair the appearance of the product. *
また、接着剤４ｂが中間層５の縁よりもはみ出して塗布されることがある。この状態で接着剤４ｂを硬化させると、スタンパが接着されて剥離しにくくなる。その結果、スタンパを剥離するときに大きな応力がかかり、中間層５に割れや欠けがしばしば発生する。　 Further, the adhesive 4 b may be applied so as to protrude beyond the edge of the intermediate layer 5. If the adhesive 4b is cured in this state, the stamper is adhered and is difficult to peel off. As a result, a large stress is applied when the stamper is peeled off, and the intermediate layer 5 is often cracked or chipped. *
また、接着剤層４は厚さ調整の役割を有するため、基板２と中間層５とを貼りあわせるときに、中間層５と接着剤層４とを合わせた厚さが所定の厚さになるように貼りあわせる。この場合図１７に示すように、余分な接着剤が中間層５の内周縁よりはみ出すことがある。この状態で接着剤層４を硬化させると、スタンパが接着されて剥離しにくくなる。その結果、スタンパを剥離するときに大きな応力がかかり、図１８に示すように、中間層５に割れや欠けが生じることがある。また、はみ出した接着剤により、中間層５の内周縁に蛇行が生じ、この蛇行により、製品の外観が損なわれることがある。 Further, since the adhesive layer 4 has a role of adjusting the thickness, when the substrate 2 and the intermediate layer 5 are bonded together, the combined thickness of the intermediate layer 5 and the adhesive layer 4 becomes a predetermined thickness. Paste together. In this case, as shown in FIG. 17, excess adhesive may protrude from the inner peripheral edge of the intermediate layer 5. When the adhesive layer 4 is cured in this state, the stamper is adhered and is difficult to peel off. As a result, a large stress is applied when the stamper is peeled off, and the intermediate layer 5 may be cracked or chipped as shown in FIG. Further, the protruding adhesive causes meandering at the inner peripheral edge of the intermediate layer 5, and this meandering may impair the appearance of the product.
そこで本発明では、螺旋状または同心円状に並んだ凹部を一方の面に有するディスク状の基板と、前記基板の一方の面上に形成された第一の情報記録層と、前記第一の情報記録層上に形成されかつ螺旋状または同心円状に並んだ凹部を一方の面に有している中間層と、前記中間層の一方の面上に形成された第二の情報記録層と、を有する多層型光情報記録媒体において、前記中間層の内周縁近傍に、連続的あるいは断続的に同心円状の溝が形成されている多層型光情報記録媒体を提案する。 Therefore, in the present invention, a disk-shaped substrate having concave portions arranged in a spiral or concentric shape on one surface, a first information recording layer formed on one surface of the substrate, and the first information An intermediate layer formed on one surface with concave portions formed on the recording layer and arranged in a spiral or concentric circle; and a second information recording layer formed on one surface of the intermediate layer, In this multilayer optical information recording medium, a multilayer optical information recording medium is proposed in which concentric grooves are formed continuously or intermittently in the vicinity of the inner periphery of the intermediate layer.
　この同心円状の溝により、接着剤のはみ出しが抑制されるので、製品の外観の悪化を低減することができる。また、接着剤によってスタンパが接着されるのを抑制することができるので、スタンパを剥離するときの応力が低減され、中間層の割れや欠けを防止することができる。 Since the concentric grooves prevent the adhesive from protruding, deterioration of the appearance of the product can be reduced. Moreover, since it can suppress that a stamper adhere | attaches with an adhesive agent, the stress at the time of peeling a stamper is reduced, and the crack and notch | chip of an intermediate | middle layer can be prevented.
　なお、中間層の内周縁近傍については、多層型光情報記録媒体の中心から半径１０．５～１２．５ｍｍの範囲が好適な範囲である。多層型光情報記録媒体の中心から半径１０．５ｍｍの位置は中間層の内周縁に相当する。すなわち、中間層の内周縁から外周に向かって２．０ｍｍの範囲内に同心円状の溝が形成されていると好ましい。 For the vicinity of the inner peripheral edge of the intermediate layer, a radius of 10.5 to 12.5 mm from the center of the multilayer optical information recording medium is a suitable range. A position having a radius of 10.5 mm from the center of the multilayer optical information recording medium corresponds to the inner peripheral edge of the intermediate layer. That is, it is preferable that concentric grooves are formed within a range of 2.0 mm from the inner peripheral edge of the intermediate layer toward the outer periphery.
本発明によれば、外観が良好で、中間層の割れや欠け等の欠損の少ない多層型光情報記録媒体を得ることができる。 According to the present invention, it is possible to obtain a multilayer type optical information recording medium having a good appearance and few defects such as cracks and chips in the intermediate layer.
本発明の多層型光情報記録媒体を模式的に示す平面図である。1 is a plan view schematically showing a multilayer optical information recording medium of the present invention. 図１のＡ－Ａ線における断面を模式的に示す図で、本発明の第一の実施形態を示す図である。FIG. 2 is a diagram schematically showing a cross section taken along the line AA of FIG. 1 and showing the first embodiment of the present invention. 本発明の多層型光情報記録媒体の製造プロセスを示す図で、第一の情報記録層が形成された基板を示す図である。It is a figure which shows the manufacturing process of the multilayer type | mold optical information recording medium of this invention, and is a figure which shows the board | substrate with which the 1st information recording layer was formed. 本発明の多層型光情報記録媒体の製造プロセスを示す図で、中間層をスタンパ上に形成した状態を示す図である。It is a figure which shows the manufacturing process of the multilayer type | mold optical information recording medium of this invention, and is a figure which shows the state which formed the intermediate | middle layer on the stamper. 本発明の多層型光情報記録媒体の製造プロセスを示す図で、中間層に切り込みを入れるプロセスを示す図である。It is a figure which shows the manufacturing process of the multilayer type | mold optical information recording medium of this invention, and is a figure which shows the process which cuts into an intermediate | middle layer. 本発明の多層型光情報記録媒体の製造プロセスを示す図で、中間層に接着剤層を形成した状態を示す図である。It is a figure which shows the manufacturing process of the multilayer type | mold optical information recording medium of this invention, and is a figure which shows the state which formed the adhesive bond layer in the intermediate | middle layer. 本発明の多層型光情報記録媒体の製造プロセスを示す図で、第一の情報記録層が形成された基板と、中間層とを貼りあわせるプロセスを示す図である。It is a figure which shows the manufacturing process of the multilayer type | mold optical information recording medium of this invention, and is a figure which shows the process of bonding the board | substrate with which the 1st information recording layer was formed, and an intermediate | middle layer. 本発明の多層型光情報記録媒体の製造プロセスを示す図で、第一の情報記録層が形成された基板と、中間層とを貼りあわせた状態を示す図である。It is a figure which shows the manufacturing process of the multilayer type | mold optical information recording medium of this invention, and is a figure which shows the state which bonded together the board | substrate with which the 1st information recording layer was formed, and the intermediate | middle layer. 本発明の多層型光情報記録媒体の製造プロセスを示す図で、中間層からスタンパを剥離した状態を示す図である。It is a figure which shows the manufacturing process of the multilayer type | mold optical information recording medium of this invention, and is a figure which shows the state which peeled the stamper from the intermediate | middle layer. 本発明の多層型光情報記録媒体の製造プロセスを示す図で、、第一の情報記録層が形成された基板と、中間層とを貼りあわせた状態の別例を示す図である。It is a figure which shows the manufacturing process of the multilayer type optical information recording medium of this invention, Comprising: It is a figure which shows another example of the state which bonded together the board | substrate with which the 1st information recording layer was formed, and the intermediate | middle layer. 図１のＡ－Ａ線における断面を模式的に示す図で、本発明の第二の実施形態を示す図である。FIG. 3 is a diagram schematically showing a cross section taken along line AA of FIG. 1, and is a diagram showing a second embodiment of the present invention. 図１のＡ－Ａ線における断面を模式的に示す図で、本発明の第三の実施形態を示す図である。FIG. 6 is a diagram schematically showing a cross section taken along line AA in FIG. 1, and showing a third embodiment of the present invention. 従来の多層型光情報記録媒体の製造プロセスを示す図である。It is a figure which shows the manufacturing process of the conventional multilayer type | mold optical information recording medium. 従来の多層型光情報記録媒体の製造プロセスを示す図である。It is a figure which shows the manufacturing process of the conventional multilayer type | mold optical information recording medium. 従来の多層型光情報記録媒体の製造プロセスを示す図である。It is a figure which shows the manufacturing process of the conventional multilayer type | mold optical information recording medium. 従来の多層型光情報記録媒体の製造プロセスを示す図である。It is a figure which shows the manufacturing process of the conventional multilayer type | mold optical information recording medium. 従来の多層型光情報記録媒体の製造プロセスを示す図である。It is a figure which shows the manufacturing process of the conventional multilayer type | mold optical information recording medium. 従来の多層型光情報記録媒体の問題点を示す図である。It is a figure which shows the problem of the conventional multilayer type | mold optical information recording medium.
本発明の多層型光情報記録媒体に係る第一の実施形態について、図面に基づいて説明する。図１は本発明の多層型光ディスクの平面図、図２は図１のＡ－Ａ線における部分断面図であり、ＢＤ－Ｒの場合の断面を示す。 A first embodiment of the multilayer optical information recording medium of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a multilayer optical disc according to the present invention, and FIG. 2 is a partial cross-sectional view taken along the line AA in FIG.
　図１および図２に示す多層型光ディスク１は、中心孔を有し、この中心孔の外側にクランピングエリアが形成され、さらにその外側に記録エリアが形成されている。そして中間層５の内周縁近傍には同心円状の溝７が断続的に形成されている。なお、中間層５の内周縁近傍は、クランピングエリア内で本発明の効果が発揮されるような範囲であり、ディスクの中心から半径１０．５ｍｍの位置にある中間層の内周縁から外周に向かって２．０ｍｍの範囲、すなわちディスクの中心から半径１０．５ｍｍ～１２．５ｍｍの範囲が特に好ましい。 1 and 2 has a center hole, a clamping area is formed outside the center hole, and a recording area is formed outside the center area. Concentric grooves 7 are intermittently formed in the vicinity of the inner peripheral edge of the intermediate layer 5. The vicinity of the inner peripheral edge of the intermediate layer 5 is a range in which the effect of the present invention is exerted in the clamping area, from the inner peripheral edge of the intermediate layer located at a radius of 10.5 mm from the center of the disk to the outer periphery. A range of 2.0 mm toward the disk, that is, a radius of 10.5 mm to 12.5 mm from the center of the disk is particularly preferable.
　図２の多層型光ディスク１’は次のような構成を有している。螺旋状または同心円状の案内溝ＧＶ１が一方の面に形成されているディスク状の基板２を有している。基板２の一方の面上に第一の情報記録層３が形成されている。この第一の情報記録層３上に、螺旋状または同心円状の案内溝ＧＶ２を一方の面に有している中間層５が接着剤層４を介して形成されている。そして中間層５の上に第二の情報記録層６が形成されている。そして第二の情報記録層６上に光透過層８が形成されている。第一の情報記録層３は、基板２の一方の面上に形成された反射層３ａと、反射層３ａ上に形成された光吸収層３ｂと、光吸収層３ｂ上に形成された保護層３ｃと、で構成されている。また、第二の情報記録層３は、中間層５上に形成された反射層６ａと、反射層６ａ上に形成された光吸収層６ｂと、光吸収層６ｂ上に形成された保護層６ｃと、で構成されている。そして、中間層５の内周縁近傍には、同心円状の溝７が形成されている。 The multilayer optical disc 1 'in FIG. 2 has the following configuration. A spiral or concentric guide groove GV1 is provided with a disk-shaped substrate 2 formed on one surface. A first information recording layer 3 is formed on one surface of the substrate 2. On the first information recording layer 3, an intermediate layer 5 having a spiral or concentric guide groove GV2 on one surface is formed via an adhesive layer 4. A second information recording layer 6 is formed on the intermediate layer 5. A light transmission layer 8 is formed on the second information recording layer 6. The first information recording layer 3 includes a reflective layer 3a formed on one surface of the substrate 2, a light absorbing layer 3b formed on the reflective layer 3a, and a protective layer formed on the light absorbing layer 3b. 3c. The second information recording layer 3 includes a reflective layer 6a formed on the intermediate layer 5, a light absorbing layer 6b formed on the reflective layer 6a, and a protective layer 6c formed on the light absorbing layer 6b. And is composed of. A concentric groove 7 is formed near the inner periphery of the intermediate layer 5.
基板２は、厚さが１．１ｍｍを有する直径１２０ｍｍの円板状の基板である。この基板２には、従来の光ディスクの基板材料として用いられている各種の材料を任意に選択して使用することができる。具体的には、ポリカーボネート、ポリメチルメタクリレート等のアクリル樹脂、ポリ塩化ビニル、塩化ビニル共重合体等の塩化ビニル系樹脂、エポキシ樹脂、アモルファスポリオレフィン、ポリエステル樹脂、アルミニウム等の金属、ガラス等を挙げることができ、必要によりこれらを組み合わせまたは混合する等の方法で併用してもよい。上記材料の中では、成型性、耐湿性、寸法安定性及び低価格等の点から熱可塑性樹脂が好ましく、ポリカーボネートが特に好ましい。このような基板２は、射出成形によって形成される。このとき、金型内にスタンパがセットされており、これによって基板２に螺旋状または同心円状の案内溝ＧＶ１が形成される。この案内溝ＧＶ１は０．３２μｍ～０．３５μｍのピッチで形成されており、ピットはこの案内溝ＧＶ１内に形成される。 The substrate 2 is a disc-shaped substrate having a thickness of 1.1 mm and a diameter of 120 mm. Various materials used as the substrate material of the conventional optical disc can be arbitrarily selected and used for the substrate 2. Specific examples include acrylic resins such as polycarbonate and polymethyl methacrylate, vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers, epoxy resins, amorphous polyolefins, polyester resins, metals such as aluminum, and glass. If necessary, these may be used in combination or by a method such as mixing. Among the above materials, a thermoplastic resin is preferable from the viewpoint of moldability, moisture resistance, dimensional stability, and low price, and polycarbonate is particularly preferable. Such a substrate 2 is formed by injection molding. At this time, a stamper is set in the mold, whereby a spiral or concentric guide groove GV1 is formed in the substrate 2. The guide groove GV1 is formed with a pitch of 0.32 μm to 0.35 μm, and pits are formed in the guide groove GV1.
第一の情報記録層３の反射層３ａは、Ａｇ合金やＡｌ合金等の反射率の高い金属薄膜で形成されており、スパッタリング等によって形成される。この反射層３ａは入射した光を全反射しても良いので、厚さは５５ｎｍ～６５ｎｍが好ましい。光吸収層３ｂは有機色素を用いたものと、無機材料を用いたものがある。有機色素を用いた光吸収層３ｂの場合、シアニン系色素やアゾ系色素等の有機色素を例えばＴＦＰ等の溶媒に溶かしたものを、スピンコート法によって塗布することによって形成される。光吸収層３ｂに用いられる色素は、波長４０５ｎｍのレーザ光を吸収して分解される特性を有している。一方、無機材料を用いた光吸収層３ｂの場合、例えばＴｅ－Ｐｄのような相変化型、Ｓｉ膜とＣｕ合金膜を積層した合金型、あるいはＢｉ－ＮとＧｅ－Ｎが混在する分解反応型が挙げられる。これらの無機材料系の光吸収層３ｂはスパッタリング法によって形成される。保護層３ｃは、有機色素系の光吸収層３ｂの場合、中間層５の形成時における光吸収層３ｂに含まれる色素の中間層５への拡散や、中間層５となる硬化性樹脂の溶剤等の光吸収層３ｂへの浸透などの混和現象を防止するためのものである。この保護層３ｃを構成する材料は、酸化珪素とくに二酸化珪素や、酸化亜鉛、酸化セリウム、酸化イットリウム等の酸化物；硫化亜鉛、硫化イットリウムなどの硫化物；窒化珪素などの窒化物；炭化珪素；酸化物とイオウ化合物との混合物などが挙げられる。また、無機材料系の光吸収層３ｂの場合、この保護層３ｃと同じものを、光吸収性を向上するための誘電体膜として形成する。この保護層３ｃはスパッタリング等の方法で形成される。これらの反射層３ａ、光吸収層３ｂおよび保護層３ｃによって第一の情報記録層３が構成されている。 The reflective layer 3a of the first information recording layer 3 is formed of a metal thin film having a high reflectance such as an Ag alloy or an Al alloy, and is formed by sputtering or the like. Since the reflection layer 3a may totally reflect the incident light, the thickness is preferably 55 nm to 65 nm. The light absorption layer 3b includes one using an organic dye and one using an inorganic material. In the case of the light absorption layer 3b using an organic dye, it is formed by applying a solution obtained by dissolving an organic dye such as a cyanine dye or an azo dye in a solvent such as TFP by a spin coating method. The dye used for the light absorption layer 3b has a characteristic of being decomposed by absorbing laser light having a wavelength of 405 nm. On the other hand, in the case of the light absorption layer 3b using an inorganic material, for example, a phase change type such as Te—Pd, an alloy type in which a Si film and a Cu alloy film are laminated, or a decomposition reaction in which Bi—N and Ge—N are mixed. A type is mentioned. These inorganic material-based light absorption layers 3b are formed by sputtering. In the case of the organic dye-based light absorption layer 3b, the protective layer 3c is a solvent of a curable resin that becomes the intermediate layer 5 and the diffusion of the dye contained in the light absorption layer 3b when the intermediate layer 5 is formed. This is to prevent a mixing phenomenon such as penetration into the light absorption layer 3b. The material constituting the protective layer 3c is silicon oxide, particularly silicon dioxide, oxides such as zinc oxide, cerium oxide, yttrium oxide; sulfides such as zinc sulfide and yttrium sulfide; nitrides such as silicon nitride; silicon carbide; Examples thereof include a mixture of an oxide and a sulfur compound. In the case of the inorganic material-based light absorption layer 3b, the same layer as the protective layer 3c is formed as a dielectric film for improving light absorption. The protective layer 3c is formed by a method such as sputtering. The reflective layer 3a, the light absorbing layer 3b, and the protective layer 3c constitute the first information recording layer 3.
中間層は５、液状の硬化性樹脂をスピンコート法等によって樹脂性あるいは金属性のスタンパ上に塗布して硬化させる方法で形成され、接着剤層４を介して基板２と貼りあわされる。硬化性樹脂としては例えば商品名：ＳＤ－６９４（ＤＩＣ（株）製）等の紫外線硬化性樹脂が好適に用いられている。中間層５の一方の面には、螺旋状または同心円状の案内溝ＧＶ２が０．３２μｍ～０．３５μｍのピッチで形成されている。 The intermediate layer 5 is formed by a method in which a liquid curable resin is applied on a resinous or metallic stamper by a spin coating method or the like and cured, and is bonded to the substrate 2 via the adhesive layer 4. As the curable resin, for example, an ultraviolet curable resin such as trade name: SD-694 (manufactured by DIC Corporation) is suitably used. On one surface of the intermediate layer 5, spiral or concentric guide grooves GV2 are formed with a pitch of 0.32 μm to 0.35 μm.
　第二の情報記録層６の反射層６ａは、Ａｇ合金やＡｌ合金等の反射率の高い金属薄膜で形成されており、スパッタリング等によって形成される。第二の情報記録層６の反射層６ａは入射した光を反射させる場合と透過させる場合があるため、半透過性であることが必要である。そのため、厚さは第一の情報記録層３の反射層３ａよりも薄い金属膜が好ましく、２０ｎｍ～３０ｎｍが好ましい。光吸収層６ｂおよび保護層６ｃは、第一の情報記録層３の光吸収層３ｂおよび保護層３ｃと略同じである。これらの半透過性の反射層６ａ、光吸収層６ｂおよび保護層６ｃによって第二の情報記録層６が構成されている。 The reflective layer 6a of the second information recording layer 6 is formed of a metal thin film having high reflectivity such as Ag alloy or Al alloy, and is formed by sputtering or the like. Since the reflective layer 6a of the second information recording layer 6 may reflect or transmit incident light, it needs to be semi-transmissive. Therefore, a metal film that is thinner than the reflective layer 3a of the first information recording layer 3 is preferable, and preferably 20 nm to 30 nm. The light absorption layer 6b and the protective layer 6c are substantially the same as the light absorption layer 3b and the protective layer 3c of the first information recording layer 3. The semi-transmissive reflective layer 6a, the light absorbing layer 6b, and the protective layer 6c constitute a second information recording layer 6.
　光透過層８は、光透過性の樹脂で形成されており、紫外線または放射線によって硬化する硬化性樹脂をスピンコート法等によって形成するか、紫外線または放射線によって硬化する樹脂シートを、透明接着剤を介して貼りつけて形成する。この光透過層８の光透過率は、硬化後の厚み０．１ｍｍで、４０５ｎｍの波長の光にて分光光度計で測定したときに７０％以上好ましくは８０％以上である。なお、光透過層８は比較的柔らかく、傷が付きやすいので、光入射側の表面にアクリル系樹脂等で構成されたハードコート層（図示せず）を設けても良い。 The light transmissive layer 8 is formed of a light transmissive resin. A curable resin that is cured by ultraviolet rays or radiation is formed by a spin coating method or the like, or a resin sheet that is cured by ultraviolet rays or radiation is formed by using a transparent adhesive. To be formed. The light transmittance of the light-transmitting layer 8 is not less than 70%, preferably not less than 80% when measured with a spectrophotometer with a light having a wavelength of 405 nm with a thickness of 0.1 mm after curing. Since the light transmission layer 8 is relatively soft and easily damaged, a hard coat layer (not shown) made of an acrylic resin or the like may be provided on the surface on the light incident side.
　次に、本発明の多層型光ディスクの製造プロセスについて説明する。まず図３に示すように、第一の情報記録層３が形成された基板２を用意する。これは単層の光ディスクの通常のプロセスによって形成される。原版となるＮｉスタンパをセットした金型内に射出成形機によってポリカーボネートを射出し、一方の面に０．３２μｍ～０．３５μｍのピッチの螺旋状の案内溝ＧＶ１を有する厚さ１．１ｍｍの基板２を形成する。金型から基板２を取り出し、案内溝ＧＶ１を有する面にスパッタによってＡｇ合金膜を形成し、反射層３ａを形成する。続いてスピンコート法によって、有機色素をＴＦＰ等の溶剤に溶かした溶液を反射層３ａ上に塗布し、乾燥して光吸収層３ｂを形成する。続いてスパッタによって保護層３ｃを形成する。 Next, the manufacturing process of the multilayer optical disc of the present invention will be described. First, as shown in FIG. 3, a substrate 2 on which a first information recording layer 3 is formed is prepared. This is formed by the normal process of a single layer optical disc. A substrate having a thickness of 1.1 mm having a spiral guide groove GV1 with a pitch of 0.32 μm to 0.35 μm on one surface, in which polycarbonate is injected by an injection molding machine into a mold in which a Ni stamper as an original is set 2 is formed. The substrate 2 is taken out from the mold, and an Ag alloy film is formed on the surface having the guide groove GV1 by sputtering to form the reflective layer 3a. Subsequently, a solution obtained by dissolving an organic dye in a solvent such as TFP is applied onto the reflective layer 3a by spin coating, and dried to form the light absorption layer 3b. Subsequently, the protective layer 3c is formed by sputtering.
　一方、図４に示すように、中間層５を作製する。まず、中間層５に案内溝ＧＶ２を形成するための樹脂スタンパを用意する。原版となるＮｉスタンパをセットした金型内に射出成形機によってポリカーボネートあるいはゼオノア（商品名：日本ゼオン（株）製）を射出し、案内溝の逆パターンとなる突起を有する樹脂スタンパが形成される。金型から樹脂スタンパを取り出し、スピンコート法によってスタンパ上に硬化性樹脂を例えば２０μｍの厚さに塗布する。その後硬化性樹脂を硬化させて中間層５を形成する。 On the other hand, as shown in FIG. First, a resin stamper for forming the guide groove GV2 in the intermediate layer 5 is prepared. Polycarbonate or ZEONOR (trade name: manufactured by Nippon Zeon Co., Ltd.) is injected by an injection molding machine into a mold in which an original Ni stamper is set, and a resin stamper having protrusions that are reverse patterns of guide grooves is formed. . A resin stamper is taken out from the mold, and a curable resin is applied to the stamper to a thickness of 20 μm, for example, by spin coating. Thereafter, the curable resin is cured to form the intermediate layer 5.
　続いて図５に示すように、中間層５の内周縁近傍に切り込み７を形成する。この切り込み７を形成する方法としては、図５（ａ）に示すように、中間層５が形成されているスタンパを回転させるかまたは除去手段を周回させながら、中間層５の内周縁近傍の樹脂を除去する。除去手段としては、カッターやピンの他、炭酸ガスレーザやＹＡＧレーザなどがある。このようにして、図５（ｂ）に示すように、中間層５に切り込み７が形成される。 Subsequently, as shown in FIG. 5, a cut 7 is formed in the vicinity of the inner peripheral edge of the intermediate layer 5. As a method for forming the cuts 7, as shown in FIG. 5A, the resin near the inner peripheral edge of the intermediate layer 5 is rotated while rotating the stamper on which the intermediate layer 5 is formed or rotating the removing means. Remove. Examples of the removing means include a carbon dioxide gas laser and a YAG laser in addition to a cutter and a pin. In this way, the cuts 7 are formed in the intermediate layer 5 as shown in FIG.
　続いて図６に示すように、中間層５上に接着剤を塗布する。接着剤としては、光透過性の硬化性樹脂が好適に用いられ、例えばアクリル系の紫外線硬化性樹脂等が挙げられる。この場合、中間層５の形成に用いた紫外線硬化性樹脂と同じものを用いても良い。接着剤は切り込み７を目標として塗布を行うと、余分な接着剤が切り込みに入り込むため、塗布ばらつきによる内周縁の蛇行が軽減される。このようにして中間層上に接着剤層４ｂが形成される。 Subsequently, as shown in FIG. 6, an adhesive is applied on the intermediate layer 5. As the adhesive, a light transmissive curable resin is preferably used, and examples thereof include an acrylic ultraviolet curable resin. In this case, the same UV curable resin used for forming the intermediate layer 5 may be used. When the adhesive is applied with the cut 7 as a target, excess adhesive enters the cut, so that meandering of the inner periphery due to application variation is reduced. Thus, the adhesive layer 4b is formed on the intermediate layer.
　続いて図７に示すように、スタンパ上の中間層５を、予め用意した基板２の第一の情報記録層３上に貼りあわせる。このとき基板２側にも接着剤層４ａを形成し、互いの接着剤層を貼りあわせる。接着剤層は厚み調整の役割を持っているので、中間層５と接着剤層とを合わせた厚さが所定の厚さ例えば２５μｍになるように貼りあわせる。 Subsequently, as shown in FIG. 7, the intermediate layer 5 on the stamper is bonded onto the first information recording layer 3 of the substrate 2 prepared in advance. At this time, the adhesive layer 4a is also formed on the substrate 2 side, and the adhesive layers are bonded together. Since the adhesive layer has a role of adjusting the thickness, the adhesive layer is bonded so that the total thickness of the intermediate layer 5 and the adhesive layer is a predetermined thickness, for example, 25 μm.
　このとき、厚み調整により生じた余分な接着剤は、図８に示すように、その一部が切り込み７に入り込む。このように、余分な接着剤を切り込み７に入り込ませることで、接着剤のはみ出しを低減し、製品の外観を良好にすることができる。ここで、切り込み７に接着剤を入り込ませるとき、空気を巻き込んで切り込み７内に空間が生じる。この空間が同心円状の溝となる。この空間によって接着剤がスタンパに付着しないので、後の工程でスタンパを剥離するとき、大きな応力がかからないようにすることができる。 At this time, as shown in FIG. 8, a part of the excess adhesive generated by adjusting the thickness enters the notch 7. In this way, by allowing excess adhesive to enter the notch 7, the protrusion of the adhesive can be reduced and the appearance of the product can be improved. Here, when the adhesive is allowed to enter the notch 7, air is entrained to create a space in the notch 7. This space becomes a concentric groove. Since the adhesive does not adhere to the stamper due to this space, it is possible to prevent a large stress from being applied when the stamper is peeled off in a later step.
続いて図９に示すように、接着剤層４を硬化させて、その後スタンパを剥離する。続いて中間層５の案内溝ＧＶ２が形成されている面上に第二の情報記録層６を形成する。続いて第二の情報記録層６上に厚さ７５μｍの光透過層８を形成して、図２に示す多層型光ディスク１’を得る。 Subsequently, as shown in FIG. 9, the adhesive layer 4 is cured, and then the stamper is peeled off. Subsequently, the second information recording layer 6 is formed on the surface of the intermediate layer 5 where the guide groove GV2 is formed. Subsequently, a light transmission layer 8 having a thickness of 75 μm is formed on the second information recording layer 6 to obtain a multilayer optical disc 1 ′ shown in FIG. 2.
なお、切り込み７に接着剤を入り込ませた場合、図１０に示すように、接着剤がスタンパに付着するように切り込み７内に入り込むことがある。この部分が同心円状の溝の途切れた部分となる。このような部分では、スタンパに接着剤が付着してしまうが、その割合は小さいので、中間層５に割れや欠けを生じさせるほどにならない。切り込み７全体に空間が形成されれば、同心円状の溝は連続的な同心円となる。 When the adhesive is inserted into the notch 7, as shown in FIG. 10, the adhesive may enter the notch 7 so that the adhesive adheres to the stamper. This part becomes a part where the concentric grooves are interrupted. In such a portion, the adhesive adheres to the stamper, but since the ratio is small, the intermediate layer 5 is not cracked or chipped. If a space is formed in the entire cut 7, the concentric grooves are continuous concentric circles.
　次に、本発明の第二の実施形態について説明する。図１１の多層型光ディスク１１は、ＤＶＤ±Ｒの場合を示しており、次のような構成を有している。螺旋状または同心円状の案内溝ＧＶ１１が一方の面に形成されたディスク状の基板１２を有している。この基板１２の一方の面上に第一の情報記録層１３が形成されている。そして第一の情報記録層１３上に、螺旋状または同心円状の案内溝ＧＶ１２を一方の面に有している中間層１５が接着剤層１４ａを介して形成されている。そして該中間層１５上に第二の情報記録層１６が形成されている。そして該第二の情報記録層１６上に接着剤層１４ｂを介して形成されたダミー基板１８が形成されている。そして第一の情報記録層１３は、基板１２の一方の面上に形成された光吸収層１３ｂと、該光吸収層１３ｂ上に形成された半透過性の反射層１３ａと、で構成されている。また、第二の情報記録層１６は、中間層１５の一方の面上に形成された光吸収層１６ｂと、該光吸収層１６ｂ上に形成された反射層１６ａと、で構成されている。 Next, a second embodiment of the present invention will be described. The multilayer optical disk 11 in FIG. 11 shows a case of DVD ± R, and has the following configuration. A spiral or concentric guide groove GV11 has a disk-like substrate 12 formed on one surface. A first information recording layer 13 is formed on one surface of the substrate 12. An intermediate layer 15 having a spiral or concentric guide groove GV12 on one surface is formed on the first information recording layer 13 via an adhesive layer 14a. A second information recording layer 16 is formed on the intermediate layer 15. A dummy substrate 18 is formed on the second information recording layer 16 through an adhesive layer 14b. The first information recording layer 13 includes a light absorption layer 13b formed on one surface of the substrate 12, and a semi-transmissive reflection layer 13a formed on the light absorption layer 13b. Yes. The second information recording layer 16 is composed of a light absorption layer 16b formed on one surface of the intermediate layer 15 and a reflection layer 16a formed on the light absorption layer 16b.
　図３に示す多層型光ディスク１１は、基板１２が必ず光透過性である点、基板２の厚さが０．６ｍｍである点、基板２に対する反射層１３ａと光吸収層１３ｂの位置および中間層１５に対する反射層１６ａと光吸収層１６ｂの位置が逆になっている点、案内溝ＧＶ１１および案内溝ＧＶ１２のピッチが０．７４μｍである点、記録再生に用いられるレーザ光の波長が６５０ｎｍである点以外は、第一の実施形態の多層型光ディスク１’と略同じ構成である。また、製造プロセスについては、本発明の要部となる中間層の形成については第一の実施形態と同様である。 The multilayer optical disk 11 shown in FIG. 3 is that the substrate 12 is necessarily light transmissive, the thickness of the substrate 2 is 0.6 mm, the positions of the reflection layer 13a and the light absorption layer 13b with respect to the substrate 2, and the intermediate layer. 15, the positions of the reflective layer 16a and the light absorbing layer 16b are reversed, the pitch of the guide groove GV11 and the guide groove GV12 is 0.74 μm, and the wavelength of the laser light used for recording and reproduction is 650 nm Except for this point, the configuration is substantially the same as the multilayer optical disc 1 ′ of the first embodiment. As for the manufacturing process, the formation of the intermediate layer that is the main part of the present invention is the same as in the first embodiment.
　次に、本発明の第三の実施形態について説明する。図１２の多層型光ディスク２１は、ＢＤ－ＲＯＭの場合を示しており、次のような構成を有している。螺旋状または同心円状に並んだピットＰＴ１が一方の面に形成されたディスク状の基板２２を有している。この基板２２の一方の面上第一の情報記録層２３が形成されている。そして第一の情報記録層２３上に、螺旋状または同心円状に並んだピットＰＴ２を一方の面に有している中間層２５が接着剤層２４を介して形成されている。そして該中間層２５の一方の面上に第二の情報記録層２６が形成されている。そして該第二の情報記録層２６上に光透過層２８が形成されている。なお、図１２に示す多層光ディスク２２は、読み出し専用なので、第一の情報記録層２３は全反射金属膜のみで構成されている。また、第二の情報記録層２６は半透過反射金属膜のみで構成されている。 Next, a third embodiment of the present invention will be described. The multilayer optical disk 21 of FIG. 12 shows a case of a BD-ROM, and has the following configuration. A pit PT1 arranged in a spiral or concentric manner has a disk-like substrate 22 formed on one surface. A first information recording layer 23 is formed on one surface of the substrate 22. On the first information recording layer 23, an intermediate layer 25 having pits PT2 arranged spirally or concentrically on one surface is formed via an adhesive layer 24. A second information recording layer 26 is formed on one surface of the intermediate layer 25. A light transmission layer 28 is formed on the second information recording layer 26. Since the multilayer optical disk 22 shown in FIG. 12 is read-only, the first information recording layer 23 is composed only of a total reflection metal film. The second information recording layer 26 is composed only of a transflective metal film.
　図１２に示す多層型光ディスク２１は、基板２２および中間層２５にピット列が形成されている点と、第一の情報記録層２３および第二の情報記録層２６に光吸収層が存在しない点以外は、第一の実施形態の多層型光ディスク１’と略同じ構成である。また、製造プロセスについては、本発明の要部となる中間層の形成については第一の実施形態と同様である。 The multilayer optical disk 21 shown in FIG. 12 has a point that pit rows are formed on the substrate 22 and the intermediate layer 25, and a point that no light absorption layer exists in the first information recording layer 23 and the second information recording layer 26. Other than that, the configuration is substantially the same as that of the multilayer optical disc 1 ′ of the first embodiment. As for the manufacturing process, the formation of the intermediate layer that is the main part of the present invention is the same as in the first embodiment.
以上、本発明について説明してきたが、上記の実施形態に限定されるものではなく、本発明の範囲内において種々の変更が可能である。 Although the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.
　　１、１’、１１、２１　多層型光ディスク
　　２、１２、２２　基板　
　　３、１３、２３　第一の情報記録層
　　３ａ、１３ａ、　反射層
　　３ｂ、１３ｂ　光吸収層
　　３ｃ　保護層
　　４、１４、２４　接着剤層
　　５、１５、２５　中間層
　　６、１６、２６　第二の情報記録層　
　　６ａ、１６ａ、　反射層
　　６ｂ、１６ｂ　光吸収層
　　６ｃ　保護層
　　７、１７、２７　同心円状の溝（切り込み）
　　８、２８　光透過層　
　　１８、ダミー基板
  1, 1 ', 11, 21 Multi-layer type optical disc 2, 12, 22 Substrate
3, 13, 23 First information recording layer 3a, 13a, reflective layer 3b, 13b light absorbing layer 3c protective layer 4, 14, 24 adhesive layer 5, 15, 25 intermediate layer 6, 16, 26 second information Recording layer
6a, 16a, reflective layer 6b, 16b light absorption layer 6c protective layer 7, 17, 27 concentric grooves (notches)
8, 28 Light transmission layer
18, dummy substrate

Claims (2)

  1. 螺旋状または同心円状に並んだ凹部を一方の面に有するディスク状の基板と、前記基板の一方の面上に形成された第一の情報記録層と、前記第一の情報記録層上に形成されかつ螺旋状または同心円状に並んだ凹部を一方の面に有している中間層と、前記中間層の一方の面上に形成された第二の情報記録層と、を有する多層型光情報記録媒体において、前記中間層の内周縁近傍に、連続的あるいは断続的な同心円状の溝が形成されていることを特徴とする多層型光情報記録媒体。 A disk-shaped substrate having concave portions arranged in a spiral or concentric shape on one surface, a first information recording layer formed on one surface of the substrate, and formed on the first information recording layer Multi-layer type optical information comprising: an intermediate layer having concave portions arranged in a spiral or concentric circle on one surface; and a second information recording layer formed on one surface of the intermediate layer A multilayer optical information recording medium, wherein a continuous or intermittent concentric groove is formed in the vicinity of the inner periphery of the intermediate layer.
  2. 　前記中間層の内周縁近傍は、前記多層型光情報記録媒体の中心から１０．５～１２．５ｍｍの範囲であることを特徴とする請求項１に記載の多層型光情報記録媒体。
     
    　
    　     2. The multilayer optical information recording medium according to claim 1, wherein the vicinity of the inner peripheral edge of the intermediate layer is in the range of 10.5 to 12.5 mm from the center of the multilayer optical information recording medium.


PCT/JP2010/056000 2009-04-07 2010-04-01 Multilayer optical information recording medium WO2010116945A1 (en)

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Citations (6)

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JPH08321074A (en) * 1995-02-15 1996-12-03 Matsushita Electric Ind Co Ltd Optical information medium, its production and producing device therefor
JPH1092015A (en) * 1996-09-18 1998-04-10 Sony Disc Technol:Kk Optical disk
JPH1139734A (en) * 1997-07-23 1999-02-12 Sony Corp Production of optical recording medium
JP2002074756A (en) * 2000-08-31 2002-03-15 Matsushita Electric Ind Co Ltd Optical disk, method for manufacturing the same and molding die for disk molded body
JP2002260307A (en) * 2000-09-12 2002-09-13 Matsushita Electric Ind Co Ltd Method and apparatus for manufacturing optical information recording medium, and optical information recording medium
WO2007114285A1 (en) * 2006-03-31 2007-10-11 Mitsubishi Kagaku Media Co., Ltd. Method for manufacturing optical recording medium

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08321074A (en) * 1995-02-15 1996-12-03 Matsushita Electric Ind Co Ltd Optical information medium, its production and producing device therefor
JPH1092015A (en) * 1996-09-18 1998-04-10 Sony Disc Technol:Kk Optical disk
JPH1139734A (en) * 1997-07-23 1999-02-12 Sony Corp Production of optical recording medium
JP2002074756A (en) * 2000-08-31 2002-03-15 Matsushita Electric Ind Co Ltd Optical disk, method for manufacturing the same and molding die for disk molded body
JP2002260307A (en) * 2000-09-12 2002-09-13 Matsushita Electric Ind Co Ltd Method and apparatus for manufacturing optical information recording medium, and optical information recording medium
WO2007114285A1 (en) * 2006-03-31 2007-10-11 Mitsubishi Kagaku Media Co., Ltd. Method for manufacturing optical recording medium

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