Classifications

• • 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
  • G11B7/24094—Indication parts or information parts for identification
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
  • G11B23/38—Visual features other than those contained in record tracks or represented by sprocket holes the visual signals being auxiliary signals
  • G11B23/40—Identifying or analogous means applied to or incorporated in the record carrier and not intended for visual display simultaneously with the playing-back of the record carrier, e.g. label, leader, photograph
• • 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
  • G11B7/002—Recording, reproducing or erasing systems characterised by the shape or form of the carrier
  • G11B7/0037—Recording, reproducing or erasing systems characterised by the shape or form of the carrier with discs
• • 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
• • 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
  • G11B7/24053—Protective topcoat layers lying opposite to the light entrance side, e.g. layers for preventing electrostatic charging

Definitions

• the present invention relates to an optical information recording medium capable of optically recording / reproducing information, and more particularly, to an optical information recording / reproducing apparatus capable of optically recording / reproducing electronic information and using a laser beam on a label surface side for visual information.
• the present invention relates to an optical information recording medium capable of recording satisfactorily.
• optical information recording media that perform recording and reproduction using laser light are attracting attention as large-capacity recording media because they can record, store, and reproduce information at high density.
• optical information recording media include phase-change optical recording media represented by CD-RW and DVD-RW, and organic dye-based optical recordings represented by CD-R and DVD-R.
• the contents of the electronic information recorded on such an optical information recording medium can be confirmed by optically reproducing the information.
• displaying the contents of the electronic information on the surface of the medium as visible information is a matter of information management. That's logically important.
• a display method conventionally, for example, the content of electronic information is printed and recorded on a label surface of the medium (the surface opposite to the surface on which electronic information is recorded) by an ink jet printer or a thermal printer. Method, a method of attaching a label or the like recording the contents of electronic information, etc. are adopted.
• the laser light reported in JP-A-2000-1773966 or JP-A-2001-2836464 described above makes visible information on the label side of the medium.
• the method of recording visible information on the label side of the medium with laser light uses changes in reaction, melting, and precipitation caused by heat.Excessive laser irradiation can reduce the amount of electronic information recorded on the medium. Careful attention must be paid to the irradiation method, as it will cause thermal effects. For this reason, in order to reduce the thermal effect on such a medium, it is necessary to use a low-output laser beam of about 10 to 20 OmW.
• the energy of the laser beam is efficiently concentrated by concentrating the low-output laser beam on a layer for recording visible information (a visible information recording layer). Is effective, but for that, it is necessary to apply a focus service.
• a reflective layer for obtaining return light used for focusing and a visible information recording layer in order to efficiently focus low-power laser light on the visible information recording layer and apply a stable focus signal, a reflective layer for obtaining return light used for focusing and a visible information recording layer.
• a layer (laser light transmitting layer) composed of a laser light transmitting body for protecting the visible light information recording layer from the laser light efficiently is provided in some cases.
• an object of the present invention is to use a laser device for recording / reproducing electronic information and to irradiate a low-power laser beam so that the electronic information recorded on the medium is visible on the label surface side without adversely affecting the information.
• An object of the present invention is to provide an optical information recording medium on which information can be recorded.
• the optical information recording medium of the present invention employs a configuration in which an outermost layer such as a laser light transmitting layer having a reduced surface roughness is provided as the outermost layer on the label side.
• the optical information recording medium of the present invention is provided with a substrate and directly or via another layer on the substrate, and visible information is recorded by laser light irradiated from a label surface side opposite to the substrate side.
• the surface roughness of the outermost layer on the label side is less than half the wavelength of the laser light emitted from the label side.
• the outermost layer preferably has a surface roughness of 1/4 or less of the wavelength of the laser beam.
• the optical information recording medium of the present invention comprises, on a substrate having a recording / reproducing guide groove and Z or pit, at least an electronic information recording layer on which digital information is recorded by light irradiated from the substrate side;
• An optical information recording medium having a layer and a visible information recording layer on which visible information is recorded by a laser beam irradiated from the label side opposite to the substrate side, wherein
• the surface roughness of the outer layer is not more than 1/2 of the wavelength of the laser light emitted from the label side. Further, it is preferable that the surface roughness of the outermost layer is / or less of the wavelength of the laser beam.
• the optical information recording medium of the present invention is formed on a base plate, and a visible information recording layer on which visible information is recorded by light irradiated from a label surface side opposite to the substrate; And an overcoat layer formed on the label side of the visible information recording layer, wherein the surface roughness of the overcoat layer is ⁇ or less of the wavelength of light.
• the optical information recording medium of the present invention is preferably provided with an overcoat layer as the outermost layer.
• the overcoat layer is preferably formed of a laser light transmitting material, and the lower limit of the thickness of the overcoat layer is 10 im, and the upper limit of the overcoat layer is 10 im. Preferably, it is formed in the range of 100.
• the overcoat layer is preferably formed such that the refractive index of the overcoat layer is in the range of 0.4 or more and 2.6 or less.
• the visible information recording layer is characterized by being formed of a material whose color developing property changes or a material whose transparency changes by light applied to the visible information recording layer.
• the optical information recording medium of the present invention comprises: an electronic information recording layer on which digital information is recorded by light irradiated from the substrate side; a reflective layer formed on the side opposite to the substrate side of the electronic information recording layer; An optical information recording medium comprising: a protective layer formed on a side of the reflective layer opposite to the substrate side, wherein the protective layer is formed on a side opposite to the substrate side and is opposite to the substrate side.
• an overcoat layer which is 1/2 or less of the above.
• the present invention provides a step of forming an electronic information recording layer on which digital information is recorded by light emitted from the substrate side on a substrate, and forming a reflective layer on the formed electronic information recording layer.
• Process a process of forming a protective layer on the formed reflective layer, and recording of visible information on the formed protective layer by laser light irradiated from the label surface side opposite to the substrate side.
• a step of forming the film by a film method a film method.
• visible information is information that is visually read, such as characters, symbols, images such as illustrations and photographs, and geometric patterns.
• Electrical information is recorded as digital signals. This means information that is read by any playback device, such as information that is being read.
• FIG. 1 is a diagram for explaining the structure of an optical information recording medium according to an embodiment of the present invention.
• FIG. 2 is a diagram for explaining a recording device that records visible information on an optical information recording medium having a visible information recording layer.
• Optical information recording medium 12: Spindle, 13: Spindle motor, 14: Steving motor, 15: Screw shaft, 16: Pickup, 17: Laser beam, 101 ... substrate, 102 ... Electronic information recording layer, 103 ... Reflective layer, 104 ... Protective layer, 105 ... Visible information recording layer, 106 ... Overcoat layer, 107 ... Laser light, 108 ... Laser light, 109... Reflected light, 200... Recording device Effect of the invention
• an optical information recording medium capable of recording visible information on a label surface by irradiating a laser with a low output of about 10 to 20 OmW.
• optical information recording medium of the present invention will be described in detail with reference to the drawings.
• FIG. 1 is a diagram for explaining the structure of an optical information recording medium according to an embodiment of the present invention.
• the optical information recording medium 100 shown here is composed of a substrate 101, an electronic information recording layer 102, and an electronic information recording layer 102 formed in this order on the substrate 101.
• the electronic information recording layer 102 provided in the optical information recording medium 100 is formed by an objective lens (not shown) of a laser device for recording / reproducing electronic information from a substrate 101.
• the recording and reproduction of electronic information is performed by the laser beam 107 incident through the.
• the optical information recording medium 100 is turned upside down and set in a laser device for recording and reproducing electronic information Z, for example, the visible information recording layer 105 is overcoated from the label side. Visible information is recorded by the laser beam 108 radiated through the. Further, a part of the laser light 108 is reflected by the reflective layer 103 provided below the visible information recording layer 105, and the reflected light 109 forms the laser light 108. Used for forcing to collect light.
• the substrate 101 is basically formed of a material transparent to the wavelength of the recording light and the reproduction light for the electronic information recording layer 102.
• Materials for forming the substrate 101 include, for example, a polycarbonate resin, an acrylic resin, a methacrylic resin, a polystyrene resin, a vinyl chloride resin,
• a polycarbonate resin is preferable because it is excellent in terms of high light transmittance, low optical anisotropy, and high mechanical strength.
• Amorphous polyolefins are preferred from the viewpoints of chemical resistance, moisture absorption resistance, optical properties and the like.
• the substrate 101 is provided with, for example, a recording / reproducing guide groove or a pit on a surface in contact with the electronic information recording layer 102, and is molded by a molding method such as injection molding.
• a molding method such as injection molding.
• Such guide grooves or pits are preferably provided at the time of molding the substrate 101.
• the guide grooves or pits may be provided on the substrate 101 using an ultraviolet (UV) hardening resin.
• UV ultraviolet
• the lower limit of the thickness of the substrate 101 is usually 1. lmm, preferably 1.15 mm
• the upper limit of the thickness is usually 1.3 mm, preferably 1.25 mm. .
• the electronic information recording layer 102 is formed of a material capable of recording electronic information (information such as information recorded by a digital signal, such as information read by some kind of reproducing device) by irradiation with a laser beam 107. Usually, it is formed as a recording layer made of an organic substance or a recording layer made of an inorganic substance. Incidentally, the electronic information recording layer 102 may be formed directly on the substrate 101, and if necessary, may be provided between the substrate 101 and the electronic information recording layer 102. May be formed via the above layer.
• organic dyes include, for example, macrocyclic azananulene dyes (phthalocyanine dyes, naphthalocyanine dyes, porphyrin dyes, etc.), polymethine dyes (cyanine dyes, merocyanine dyes, squarylium dyes, etc.), anthraquinone dyes, azurenium dyes, Azo dyes, metal-containing azo dyes, metal-containing indoor diphosphorus dyes, and the like.
• metal-containing azo dyes, cyanine dyes and phthalocyanine dyes are preferred.
• metal-containing azo dyes are preferred because of their excellent durability and light resistance.
• the method for forming the electronic information recording layer 102 made of an organic material includes a dry thin film forming method such as a vacuum evaporation method and a sputtering method, and a wet thin film forming method generally used such as a casting method, a spin coating method, and an immersion method. Law. Among them, the spin coating method is particularly preferable in terms of mass productivity and cost.
• the electronic information recording layer 102 is formed as a recording layer made of an inorganic material, for example, Rare earth transition metal alloys such as Tb'Te'Co and Dy.Fe.Co, which are recorded by the effect, are used. Also, chalcogen-based alloys such as Ge-Te and Ge-Sb.Te that change phases may be used.
• These layers may be a single layer or may be composed of two or more layers.
• Examples of a method for forming the electronic information recording layer 102 made of an inorganic substance include a vapor deposition method, an ion plating method, and a sputtering method. Among them, the sputtering method is particularly preferable in terms of mass productivity and cost.
• the thickness of the electronic information recording layer 102 varies depending on the type of the recording layer, but the lower limit is usually 5 nm, preferably 10 nm, and the upper limit is usually 500 nm, preferably 300 nm.
• the electronic information recording layer 102 of the optical information recording medium 100 of the present invention may be a recordable / erasable phase change recording layer.
• the reflective layer 103 is provided in contact with the electronic information recording layer 102 on the side opposite to the substrate 101, and usually has a function of reflecting the laser beam 107 emitted from the substrate 101 side to the substrate 101 side.
• the reflective layer 103 has an uneven shape corresponding thereto.
• a material for forming the reflective layer 103 a material having a sufficiently high reflectivity at the wavelength of the reproduction light can be used.
• Au, Al, Ag, Cu, Ti, Cr, Ni, Pt, Ta It is possible to use a metal such as Pd alone or as an alloy.
• Au, Al, and Ag have high reflectivity and are suitable as a material for the reflective layer. Those containing Ag as a main component are particularly preferable from the viewpoints of low cost and high reflectivity.
• Examples of the method for forming the reflective layer 103 include a vapor deposition method, an ion plating method, and a sputtering method. Among them, the sputtering method is particularly preferable in terms of mass productivity and cost.
• the lower limit of the thickness of the reflective layer 103 is usually 30 nm, preferably 50 nm, and the upper limit is usually 150 nm, preferably 120 nm.
• the protective layer 104 is usually formed of a material that transmits laser light, for example, an ultraviolet (UV) curable resin.
• an ultraviolet (UV) curable resin acrylate resins such as urethane acrylate, epoxy acrylate, and polyester acrylate can be used. Most of these materials can be suitably used because they are laser light transmitting substances.
• One of these ultraviolet (UV) curable resins may be used alone, or two or more thereof may be used in combination.
• the protective layer 104 may be a single-layer film or a multilayer film of two or more layers.
• a coating liquid is prepared by dissolving the ultraviolet (UV) curable resin as it is or by dissolving it in an appropriate solvent. Is applied on the reflective layer 103 and cured by irradiation with ultraviolet (UV) light.
• a coating method a spin coating method, a casting method, or the like can be employed.
• the protective layer 104 may be formed by the above-mentioned various coating methods, various wet film forming methods such as a screen printing method, and various dry film forming methods such as a vacuum evaporation method, a sputtering method, and an ion plating method.
• the protective layer 104 can be formed by a method appropriately selected according to the material used. Among them, a wet film forming method, particularly a spin coating method is preferable, and a spin coating method is generally used. Further, the lower limit of the thickness of the protective layer 104 is usually 1 / zm, preferably 3 m, and the upper limit is usually 15 ⁇ , preferably 10 / m.
• the recording material constituting the layer When the visible information recording layer 105 is irradiated with light, the recording material constituting the layer usually changes color, and as a result, the visible information (images such as characters, symbols, illustrations and photographs, geometrical Information that can be read visually, such as patterns, is recorded.
• the recording material composing the visible information recording layer 105 is not particularly limited, but as a substance that changes the absorption of visible light, it is roughly classified into the following (a) a type in which the coloring property changes, and ( b) Types that change transparency.
• Examples of the recording material of the type in which the chromogenicity changes include, for example, organic dyes generally used for optical recording of electronic information.
• organic dyes include macrocyclic azanannulene dyes (furocyanine dyes, naphthalocyanine dyes, porphyrin dyes, etc.), polymethine dyes (cyanine dyes, merocyanine dyes, squarylium purple etc.), anthraquinone dyes, Examples include azulenium dyes, azo dyes, metal-containing azo dyes, and metal-containing indoor diphosphorus dyes.
• leuco dyes having a lactone ring portion in the molecular structure may be mentioned.
• Leuco dyes are preferred because the contrast during coloring is high and the amount of heat required for coloring can be kept low.
• Specific examples of leuco dyes include 3-getylamino-7-chloroanilinofluoran, 1-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-ethylamino-6-methyl-1-7-2, 4-xyridinofluoran, 3-ethylamino-6- Fluorane compounds such as methyl-7- (m-toluidino) 1-fluoran, 3-methylamino-1,7,8-benzofluoran, 3-getylamino-6-methyl-17-xidinofluoran, etc .; crystal violet lactone, 3- (4 —Jetilwa Minnow 2—Ethoxyphenyl) 1 3— (1—Ethyl 2—Methyl India
• phthalide compounds are preferred. These leuco dyes may be used together with an electron-accepting compound or a dye that absorbs laser light for recording and generates heat, if necessary.
• the electron-accepting compound include an organic phosphoric acid compound having an aliphatic group having 6 or more carbon atoms, an aliphatic carboxylic acid compound, and a phenol compound. Preferably, it is a phenol compound.
• the electron-accepting compound include organic phosphoric acid compounds such as dodecylphosphonic acid, tetradecylphosphonic acid, hexadecylphosphonic acid, octyldecylphosphonic acid, and eicosylphosphonic acid.
• Examples of the aliphatic carboxylic acid compound include ⁇ -hydroxydecanoic acid, ⁇ -hydroxytetradecanoic acid, ⁇ ; -hydroxyhexadecanoic acid, ⁇ -hydroxyoctadecanoic acid, ⁇ -hydroxypentenodecanoic acid, and ⁇ -hydroxyeico Sannic acid, ⁇ -hydroxydocosanoic acid, ⁇ -hydroxytetracosanoic acid, ⁇ -hydroxyhexacosanoic acid, ⁇ -hydroxyoctacosanoic acid, and the like.
• phenol compound examples include a gallic acid compound, a benzoic acid compound, and a bisphenol compound. Specific examples of these compounds include methyl gallate, methyl gallate, propyl gallate, butyl gallate, lauryl gallate and the like. Examples of benzoic oxide compounds include methyl ⁇ -hydroxybenzoate, ethyl ⁇ -hydroxybenzoate, and 2,4-dihydroxybenzoic acid. Bisphenol compounds include bisphenol S, Suphenol A and the like.
• These electron accepting compounds may be used alone or in combination of two or more.
• Examples of the laser light absorbing dye include the various dyes described above as organic dyes used for optical recording of electronic information, and infrared absorbing dyes such as bisanthrone-based and indooriline-based dyes.
• an organic low-molecular compound that is dispersed in a resin base material at about 0.1 to 2 m and melts or crystallizes by heat treatment is exemplified.
• the compound for example, well-known organic low-molecular compounds having 12 or more carbon atoms, such as higher fatty acids, can be used.
• the organic low molecular weight compound may be a compound comprising a fatty acid, an aliphatic dibasic acid, a ketone, an ether, an alcohol, a fatty acid ester and a derivative thereof, or a mixture of one or more of them. It can also be used.
• fatty acid alkyl esters having 12 or more carbon atoms have a low melting point (mp) and are preferred because they melt and crystallize by heat treatment at relatively low temperature.
• an aliphatic dibasic acid having a high melting point (mp) having 10 or more carbon atoms is used in combination to adjust the mixing ratio between the fatty acid alkyl ester and the aliphatic dibasic acid. This makes it possible to adjust the temperature range for the transparency, and to change the degree of transparency and cloudiness at a predetermined temperature.
• fatty acid alkyl esters having 12 or more carbon atoms examples include methyl stearate, ethyl stearate, butyl stearate, octyl stearate, stearyl stearate, behenyl stearate, methyl behenate, and behenate.
• Examples of aliphatic dibasic acids having 10 or more carbon atoms include sebacic acid, dodecane diacid, and tetracarboxylic acid. Decane diacid, eicosane diacid and the like. When a fatty acid alkyl ester having 12 or more carbon atoms and an aliphatic dibasic acid having 10 or more carbon atoms are used in combination, the ratio of the former to the latter is preferably about 1: 1 to 10: 1, and the ratio of 2: 1: ! To 6: 1 is more preferable.
• the aliphatic dibasic acid on the high melting point side is thought to play a role in controlling the crystallization behavior as a seed crystal of the fatty acid alkyl ester on the low melting point side. If the amount is too small, the effect may be lost. If the number is too large, the contrast may be reduced.
• the visible information recording layer 105 As a method for forming the visible information recording layer 105, a known wet thin film forming method as described in the section of the method for forming the electronic information recording layer 102 can be used. Of these, spin coating or screen printing is preferred, and spin coating is more preferred. Further, the lower limit of the thickness of the visible information recording layer 105 is usually 0.1 lzm, preferably 0. The upper limit of the thickness is usually 5 m, preferably 3 m.
• the overcoat layer 106 protects the visible information recording layer 105 from physical damage and the like, and also efficiently narrows the laser beam 108 to the visible information recording layer 105. It is provided on the label side of the visible information recording layer 105 and forms the outermost layer.
• the material constituting the overcoat layer 106 is not particularly limited as long as it is a material that protects the visible information recording layer 105 from external force and the like and is transparent to laser light.
• Examples of the material constituting the overcoat layer 106 include, as the organic substance, a thermoplastic resin, a thermosetting resin, an electron beam curable resin, an ultraviolet (UV) curable resin, and the like.
• the overcoat layer 106 can be formed by dissolving a thermoplastic resin, a thermosetting resin, or the like in an appropriate solvent, applying a coating solution, and drying.
• the ultraviolet (UV) curable resin is prepared as it is or by dissolving it in an appropriate solvent to prepare a coating solution, then applying this coating solution and irradiating it with ultraviolet (UV) light to cure it.
• One coat layer 106 can be formed.
• UV curable resin for example, acrylate resins such as urethane acrylate, epoxy acrylate and polyester acrylate can be used.
• the inorganic material S i 0 2, S i N 4, M g F 2, S n 0 2 , and the like. One type of these materials may be used alone, or two or more types may be used. May be used in combination.
• the overcoat layer 106 may be a single-layer film or a multilayer film having two or more layers as long as it is transparent to the laser beam 108.
• the overcoat layer 106 is preferably formed by a wet film forming method using the above-mentioned various organic substances.
• a spin coating method, a casting method, a screen printing method, or the like can be employed as in the case of the above-described protective layer 104.
• the spin coating method is preferred because the surface smoothness is particularly high.
• a transparent substrate made of a laser light transmitting material is to be bonded in advance, it is necessary to perform accurate alignment of the substrate.
• Various measures in the manufacturing process are required, such as reducing the pressure in the bonding process so that air bubbles do not enter the layer. Therefore, from the viewpoint of productivity, it is more advantageous to form the overcoat layer 106 by a wet film forming method such as spin coating or screen printing.
• the present invention is characterized in that the surface roughness of the overcoat layer 106 is not more than 1 Z 2 of the wavelength ( ⁇ ) of the laser beam.
• the visible information recording layer 105 provided as a lower layer of the overcoat layer 106 often contains a particle component, and the surface of the visible information recording layer 105 has a height of 1 to 3 There are some irregularities.
• the surface roughness of the overcoat layer 106 is rough due to the influence of the visible information recording layer 105.
• the laser beam used in the present invention is a semiconductor laser beam, and if the semiconductor laser beam has a wavelength ( ⁇ ) of about 300 to 800 nm, the overcoat layer 106 is optionally provided. Therefore, it is considered that the surface roughness of the overcoat layer 106 does not become ⁇ or less of the wavelength ( ⁇ ) of the laser beam.
• Reducing the surface roughness of the overcoat layer 106 to 1Z2 or less of the wavelength ( ⁇ ) of the laser beam can be realized by appropriately selecting the method of forming the overcoat layer 106 and the material to be used. can do.
• the overcoat layer 106 is made of a material having a viscosity of 50 cps or more and 700 cps or less. Is preferably formed.
• the surface of the overcoat layer By setting the viscosity in this range, it is difficult for the surface of the overcoat layer to be muddy, so that the surface roughness of the overcoat layer 106 can be kept low. Further, after forming the overcoat layer 106, the surface may be subjected to a surface treatment such as polishing to suppress the surface roughness of the overcoat layer 106 to 1Z2 or less of the wavelength ( ⁇ ).
• the lower limit of the thickness of the overcoat layer 106 is 10 m, preferably 20 m, and the upper limit of the thickness is 100 rn, preferably 80 m. If the thickness of the overcoat layer 106 is smaller than the lower limit, the visible information recording layer 105 may not be able to maintain a sufficient protection function. In addition, the surface of the overcoat layer tends to be rough due to the influence of the surface roughness of the lower visible information recording layer. Further, when the thickness is higher than the upper limit, when forming the overcoat layer 106 by coating, it is necessary to repeatedly apply the overcoat layer 106, and the forming process becomes complicated. Furthermore, there is a possibility that a problem such as an increase in the warpage of the disk due to the curing shrinkage of the coating material may occur.
• the viscosity of the overcoat layer should be 50 cps or more and 7000 cps or less, and the thickness of the overcoat layer should be 10 m or more and 100 m or less. It is very effective.
• the reflectance on the surface of the overcoat layer 106 is preferably, for example, 20% or less.
• the refractive index of the overcoat layer 106 is preferably about 0.4 or more and about 2.6 or less.
• the refractive index of the overcoat layer 106 is preferably 0.5 or more and 1.9 or less.
• the surface roughness of the overcoat layer 106 forming the outermost layer on the label side is 12 or less, preferably 14 or less, of the wavelength ( ⁇ ) of the laser beam. is necessary.
• the surface roughness of the overcoat layer 106 and the like is determined as an arithmetic average roughness (Ra) measured according to Japanese Industrial Standard (JIS) No. 0601.
• the surface roughness measurement area may be any area used for recording visible information by irradiating a laser beam.
• the surface roughness of the overcoat layer 106 is 1Z2 or less, preferably 1/4 or less, of the wavelength ( ⁇ ) of the laser light, and specifically, the wavelength is 780 nm.
• the laser beam 108 radiated from the label side can be used. Irregular reflection on the surface of the overcoat layer 106 is reduced. As a result, the amount of light incident on the visible information recording layer 105 is ensured, and the reflected light 109 from the laser light 108 irradiated from the label side is stabilized, and this stable reflection is achieved. By performing focusing with the light 109, it becomes possible to record clear visible information on the visible information recording layer 105 using a low-power laser beam.
• the optical information recording medium of the present invention may have an arbitrary layer other than those described above.
• an arbitrary layer may be provided between the layers or the outermost layer of the medium, such as providing a dielectric layer sandwiching the electronic information recording layer 102. May be provided.
• the visible information recording layer does not necessarily require all the layers described above.
• the visible information recording layer may have the function of an overcoat layer by omitting the overcoat layer.
• the surface roughness of the visible information recording layer is 1 to 2 or less, preferably 1/4 or less, of the wavelength ( ⁇ ) of the laser beam, and the wavelength is 780 nm.
• the surface roughness (R a) needs to be 0.39 m or less, preferably 0.20_im or less.
• the optical recording medium may have a plurality of electronic recording layers.
• light using a substrate (first substrate) having a guide groove and Z or pit having a thickness of about 0.6 mm and a so-called dummy substrate (second substrate) having no guide groove and Z or pit is used.
• the present invention can be applied to a laminated structure including the layer Z adhesive layer / visible information recording layer Z second substrate.
• the overcoat layer and the second substrate side are the label side, respectively, and other layers may be provided as needed between each layer or as the outermost layer.
• the optical disk is not limited to a so-called substrate-surface illuminated optical disk.
• the product consisting of an overcoat layer / visible information recording layer / substrate reflective layer zelectronic information recording layer protective layer
• the present invention can be applied to a layered structure.
• the overcoat layer side is the level surface side
• the substrate has guide grooves and / or pits on the side where the information recording layer is provided.
• other layers may be provided as needed between each layer or as the outermost layer.
• optical information recording medium of the present invention will be described more specifically with reference to examples. Note that the present invention is not limited to these examples.
• FIG. 2 is a diagram for explaining a recording device that records visible information on an optical information recording medium having a visible information recording layer.
• the recording device 200 shown in FIG. 2 is such that an ordinary optical disk drive can record visible information on an optical information recording medium 11 having a visible information recording layer.
• this recording apparatus 200 is configured such that an optical information recording medium 11 is mounted on a spindle 12 and rotated by a spindle motor 13 and a screw shaft is rotated by a stepping motor 14 for feed. Rotate 1 5 and move pickup 16 to the desired position.
• the spindle motor 13 is serviced by an FG pulse signal, and the optical information recording medium 11 is adjusted to an arbitrary rotation speed.
• the optical information recording medium 11 is focused on the surface of the optical information recording medium 11 by the force sensor, and the laser beam 17 is condensed to write visible information on the optical information recording medium 11.
• the laser power is controlled by the front monitor so that it can be written with an appropriate power.
• a pulse having a duty of about 50% is applied to the optical information recording medium 11 at an output of 40 to 5 OmW.
• the spindle rotation speed is 160 to 250 rpm.
• a 1.2-mm-thick polycarbonate-ponate resin substrate with a group of 0.45 // m width and 155 nm depth was formed by injection molding.
• a fluoroalcohol solution of a metal-containing azo dye was applied by spin coating, and dried at 90 at 15 minutes to form an electronic information recording layer having a thickness of 70 nm.
• Ag was sputtered to form a reflective layer having a thickness of 70 nm.
• an ultraviolet (UV) curable resin mainly composed of acrylate monomer (“SD-374” manufactured by Dainippon Ink) is applied on the reflective layer by spin coating, and then irradiated with ultraviolet (UV) light.
• UV ultraviolet
• a protective layer having a thickness of 7 Wm was formed, and a CD-R was produced.
• 0.2 parts by weight of the color-forming organic dye shown in Table 1 0.6 parts by weight of the electron-accepting compound composed of a phenol compound, and 0 parts by weight of the bisanthrone-based infrared-absorbing dye were added. .05 parts by weight and 4 parts by weight of methyl methyl acrylate (10% by weight toluene solution) and 2.0 parts by weight of toluene were applied with a color-forming organic dye composition by spin coating. After drying at 5 Ot: for 30 minutes, a visible information recording layer was formed.
• UV curable resin mainly composed of an acrylate monomer
• spin coating a visible information recording layer
• UV light a visible information recording layer
• Overcoat layers (refractive index: 1.5) were formed, and nine types of optical information recording media having different surface roughnesses of the overcoat layers shown in Table 1 were produced.
• the nine types of optical information recording media produced in this manner were set in the recording device 200 shown in FIG. 2, respectively, and a low-power laser beam having a wavelength ( ⁇ ) of 780 nm and an output of 50 mw was used for optical information recording. Irradiation was performed from the level side of the medium to record visible information in the visible information recording layer, and the quality of forcing was indicated based on the following criteria. Table 1 shows the results.
• Example 1 Leuco dye acrylate resin 1 spin coating 130 0.06 ⁇
• Example 2 azo dye acrylate resin 1 spin coating 130 0.06 ⁇
• Example 3 Leuco dye acrylate resin 2 Spin coat 500 0.05 ⁇
• Example 4 azo dye acrylate resin 2 spin coat 500 0.06 ⁇

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