JP2007148074A - Light diffracting sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light diffracting sheet that can improve an effect of preventing forgery and has an excellent design property. <P>SOLUTION: On the back face of a substrate 10 comprising a transparent PET, a light diffracting structure forming layer 20A having a star pattern, an opaque pattern reflecting layer 20B made of a metal thin film containing magnetic powder mixed in aluminum and arranged in a row like a bar code pattern, a transparent reflecting layer 20C made of titanium oxide (TiO<SB>2</SB>), and a thermosensitive recording layer 3 are successively deposited to constitute a thermosensitive recording medium 900A. The thermosensitive recording medium 900A shows magnetism and develops complicated effects of a hologram or the like in the light diffracting structure forming layer 20A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical diffraction sheet having magnetism.

Conventionally, various cards such as credit cards, transportation commuter passes, identification cards and the like have been prevented from forgery by applying a light diffraction structure such as a hologram (for example, Patent Document 1). The optical diffraction structure requires advanced manufacturing technology and manufacturing equipment for manufacturing, and has been evaluated as a forgery prevention means such as a credit card.
However, in recent years, as the optical diffractive structure becomes widespread, its manufacturing technology and manufacturing equipment have been generalized. Along with this, there are cases in which credit cards or the like having a light diffraction structure are forged, and the anti-counterfeiting effect is gradually lost, and a new forgery prevention method is required.
Further, as the optical diffraction structure becomes widespread, there is a problem that the novelty of the design has been lost.
JP 2002-278434 A

  The subject of this invention is providing the optical diffraction sheet which can improve the effect of forgery prevention and has the outstanding designability.

  In order to solve the above problems, the invention of claim 1 is directed to an optical diffraction structure having an optical diffraction structure forming layer provided with a hologram or a diffraction grating pattern, and a reflective layer provided on the back surface of the optical diffraction structure forming layer. A light diffraction sheet comprising a layer, wherein the light diffraction structure forming layer and / or the reflection layer has magnetism.

According to a second aspect of the present invention, there is provided the optical diffraction sheet according to the first aspect, wherein the optical diffraction structure forming layer and / or the reflection layer is formed of a material containing a magnetic material. It is.
According to a third aspect of the present invention, in the optical diffraction sheet according to any one of the first to second aspects, the optical diffraction structure forming layer and / or the reflective layer are machine-readable magnetic recording units. It is a light diffraction sheet characterized by being.
According to a fourth aspect of the present invention, in the light diffraction sheet according to any one of the first to third aspects, the reflection layer is partially reflected on a back surface of the light diffraction structure forming layer. It is an optical diffraction sheet characterized by having a layer.
The invention according to claim 5 is the light diffraction sheet according to claim 4, wherein the partial reflection layer is a pattern reflection layer having a planar shape formed from a predetermined pattern. .
The invention according to claim 6 is the light diffraction sheet according to claim 4 or claim 5, wherein the reflection layer has a full reflection layer provided on the entire back surface side of the partial reflection layer. It is an optical diffraction sheet.
The invention according to claim 7 is the light diffraction sheet according to any one of claims 1 to 6, wherein the reflective layer is transparent or translucent. .
Invention of Claim 8 is provided in the back surface of the said optical diffraction structure formation layer in the optical diffraction sheet of any one of Claim 1- Claim 7, and is substantially the same as the said optical diffraction structure formation layer An optical diffraction sheet comprising a refractive index identical layer having a refractive index.
The invention according to claim 9 is the light diffraction sheet according to any one of claims 1 to 8, wherein the sheet-like base material laminated on the back side of the light diffraction structure layer, and the sheet shape An optical diffraction sheet comprising: an adhesive layer that is laminated on a back surface side of a substrate and can be attached to an adherend.
According to a tenth aspect of the present invention, in the light diffraction sheet according to any one of the first to ninth aspects, the light diffraction sheet is laminated on the back side of the light diffraction structure layer and can be attached to an adherend. An adhesive layer and a sheet-like base material that is laminated on the surface side of the light diffraction structure layer and is provided so as to be peelable are provided, and the light diffraction structure layer can be transferred to the adherend. These are optical diffraction sheets characterized by the following.
The invention of claim 11 is the light diffraction sheet according to any one of claims 1 to 10, further comprising an image receiving layer for receiving ink.
The invention according to claim 12 is the light diffraction sheet according to any one of claims 1 to 11, further comprising a tint block printing layer on which a forgery-preventing tint block is printed. It is.
A thirteenth aspect of the present invention is the light diffractive sheet according to any one of the first to twelfth aspects, further comprising a heat-sensitive recording layer that develops color when heated.

According to the present invention, the following effects can be obtained.
(1) In the present invention, since the light diffraction structure forming layer and / or the reflection layer has magnetism, the authenticity of the light diffraction sheet can be determined by detecting magnetism using a measuring instrument or the like. In addition, since the light diffraction sheet exhibits complex magnetism by forming the light diffraction structure layer so that the light diffraction structure formation layer and the reflection layer exhibit different magnetism, the effect of preventing forgery is further improved. Can do.

(2) In the present invention, since the light diffraction structure forming layer and / or the reflective layer includes a magnetic material, the layer can have magnetism, and thus the effect (1) can be obtained.

(3) In the present invention, since the light diffraction structure forming layer and / or the reflection layer is a magnetic recording unit that can be read by a machine, magnetic information can be read using a magnetic card reader or the like. Further, the light diffraction sheet is formed by stacking another layer such as a protective layer on the light diffraction structure forming layer and / or the reflection layer on which magnetic information is recorded, and the light diffraction structure formation layer and / or the reflection layer, By blocking from the outside of the card, the effect of preventing forgery can be improved.

(4) In the present invention, the reflective layer has a partially reflective layer partially provided on the back surface of the light diffraction structure forming layer.
Thereby, even if the hologram or diffraction grating pattern is provided on the entire surface of the light diffraction structure forming layer, the effect of the hologram or the like can be exhibited only in the range where the partially reflective layer is formed. Can prevent forgery used

(5) In the present invention, since the planar shape of the reflective layer is a pattern reflective layer formed from a predetermined pattern, the predetermined pattern can be recognized by detecting magnetism with a measuring instrument. The effect of prevention can be further improved. Moreover, the designability of the light diffraction sheet can be improved.

(6) In the present invention, the reflective layer has a full-surface reflective layer provided on the entire back surface side of the partial reflective layer.
Thereby, since the reflectivity, refractive index, etc. of the light rays are different between the range of the partial reflection layer and the range of the entire reflection layer, the hologram can be expressed in a more complicated manner, so that the effect of preventing forgery can be improved. it can. In addition, by making the magnetic materials contained in the light diffraction structure forming layer, the partial reflection layer, and the entire reflection layer different, or by changing the content of each magnetic material, the light diffraction sheet has more complex magnetism. As shown, the effect of preventing forgery can be further improved.

(7) In the present invention, since the reflective layer is transparent or semi-transparent, it is possible to visually recognize characters, patterns, and the like printed on the layer disposed on the back side of the reflective layer.

(8) Since the present invention includes the same refractive index layer that is provided on the back surface of the optical diffraction structure forming layer and has substantially the same refractive index as the optical diffraction structure forming layer, the optical diffraction structure forming layer and the same refractive index layer are provided. In the range where these are in direct contact with each other, the effect of a hologram or the like can be almost eliminated. (However, subtle holograms can be confirmed.)

(9) The present invention includes a sheet-like substrate laminated on the back side of the light diffraction structure layer, and an adhesive layer laminated on the back side of the sheet-like substrate and attachable to the adherend. Therefore, it can be used as a label for attaching a light diffraction structure.

(10) In the present invention, the adhesive layer that can be attached to the adherend is laminated on the back side of the light diffraction structure layer, and the sheet-like substrate is laminated on the surface side of the light diffraction structure layer. In addition, since the light diffraction structure layer can be transferred to the adherend because it is provided so as to be peelable, it can be used as a light diffraction structure transfer sheet.

(11) Since the present invention includes an image receiving layer for receiving ink, it is possible to improve printing characteristics, printing strength, and the like.

(12) Since the present invention includes the tint block printing layer on which the forgery-preventing tint block is printed, the anti-counterfeiting effect of the light diffraction sheet can be further improved.

(13) Since the present invention includes a heat-sensitive recording layer that develops color when heated, information such as characters can be recorded on the heat-sensitive recording layer using a thermal printer or the like.

  The object of the present invention is to improve the effect of preventing counterfeiting and to provide an optical diffraction sheet having excellent design properties. An optical diffraction structure forming layer, a pattern reflection layer containing a magnetic material, and the entire surface By forming a light diffraction sheet by sequentially laminating the reflection layer formed on the light diffraction sheet, the light diffraction sheet has magnetism, and it is possible to determine authenticity by mechanical reading of magnetism, thereby achieving the effect of preventing forgery. Moreover, it realized by making visible the range in which the pattern reflection layer was formed.

Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.
FIG. 1 is a view showing a laminated structure of a thermal recording medium 1 which is a first example of an optical diffraction sheet to which the present invention is applied, and FIG. 2 shows the thermal recording medium of the present invention as a target article (adhered body). FIG. 3 and FIG. 4 are diagrams showing an embodiment of a thermal recording medium.

  As shown in FIG. 1A, a thermosensitive recording medium 1 of the present invention is basically a thermosensitive recording layer 3 laminated on an optical diffraction structure layer 2 that gives a hologram or a diffraction grating pattern. The structure layer 2 is composed of a light diffraction structure forming layer 2A having fine unevenness of the light diffraction structure on the lower surface side and a reflection layer 2B formed along the fine unevenness. As shown in FIG. 1B, the heat-sensitive recording medium 1 of the present invention has the heat-sensitive recording layer 3 as the heat-sensitive recording layer A (reference numeral: 3A) and the heat-sensitive recording layer B (reference numeral: 3B) from the light diffraction structure layer 2 side. 2), or although not shown, the thermal recording layer 3 may be composed of three or more layers. Details of the light diffraction structure layer 2 are the same as those described with reference to FIG.

  The light diffractive structure forming layer 2A of the light diffractive structure layer 2 is a fine layer for providing a hologram or a diffraction grating pattern on one side of a layer made of a transparent synthetic resin, usually in order to avoid contamination or damage. Concavities and convexities are provided. Alternatively, in the case of a volume hologram, a transparent synthetic resin layer is provided with a diffraction grating for providing a hologram or a diffraction grating pattern, and in any case, it is basically transparent It is.

  As the light diffraction structure forming layer 2A, the former having fine irregularities is suitable for mass production by a method such as hot pressing. As a hologram and a diffraction grating pattern, either a plane hologram or a volume hologram can be used. A relief hologram, a Lippmann hologram, a Fresnel hologram, a Fraunhofer hologram, a lensless Fourier transform hologram, a laser reproduction hologram (image hologram, etc.), white Examples thereof include mechanically formed diffraction gratings such as light reproduction holograms (rainbow holograms), color holograms, computer holograms, hologram displays, multiplex holograms, holographic stereograms, holographic diffraction gratings, and electron beam direct drawing.

  As a material constituting the light diffraction structure forming layer 2A, a hologram or a diffraction grating pattern can be reproduced by casting or embossing. The photosensitive resin composition which can shape | mold a hardening part can be utilized. Specifically, for example, thermoplastic resins such as polyvinyl chloride, acrylic (polymethyl methacrylate), polystyrene, or polycarbonate, unsaturated polyester, melamine, epoxy, polyester (meth) acrylate, urethane (meth) acrylate, epoxy ( It is a thermosetting resin such as (meth) acrylate, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, or triazine-based acrylate, each of which is individual, thermoplastic resin, or thermosetting resin. It may be a mixture of each other or a mixture of a thermoplastic resin and a thermosetting resin. An ionizing radiation curable resin composition having a radically polymerizable unsaturated group and having thermoformability or a radically polymerizable unsaturated monomer added can also be used. The thickness of the light diffraction structure forming layer 2A is preferably about 1 to 2 μm, and when a coating composition such as an ionizing radiation curable resin composition is used, a transparent synthetic resin film is used as an object to be coated. Good.

Since the reflection layer 2B cannot obtain the visibility of the light diffraction pattern by the light diffraction structure formation layer 2A alone, or can obtain only a very low visibility even if it is obtained, the back surface of the light diffraction structure formation layer 2A. It is the layer provided in. The reflective layer 2B is provided with a reflective metal thin film made of a metal such as aluminum, or a transparent thin film made of a material having a light refractive index different from that of the light diffraction structure forming layer 2A.
The reflective layer 2B is formed in a transparent, translucent, or opaque layer depending on whether visibility of an image or the like provided in the lower layer should be ensured. That is, by making the reflective layer 2B transparent or semi-transparent, it is possible to visually recognize characters, patterns, and the like printed on a layer disposed on the back side of the reflective layer 2B.
In this embodiment, the reflective layer 2B is formed of a material in which a magnetic powder is contained in a metal or a resin, which will be described later, so that the thermal recording medium 1 exhibits magnetism.

When the reflective layer 2B is formed in an opaque layer, a metal thin film containing a magnetic material is formed, and the thickness thereof is, for example, about 50 nm or more to hide the lower layer. When the reflective layer 2B is formed as a transparent layer, the magnetic powder is contained in ZnS, TiO ₂ , Al ₂ O ₃ , Sb ₂ S ₃ , SiO, etc. having a higher refractive index than the light diffraction structure forming layer 2A. Or a material in which magnetic powder is included in LiF, MgF ₂ , and AlF ₃ having a refractive index lower than that of the light diffraction structure forming layer 2A. A light-reflecting metal thin film in which a magnetic powder is contained in aluminum or the like also becomes transparent when the thickness is 20 nm or less. Therefore, the light diffraction structure forming layer 2A as described above has a light refractive index. The same effect as a transparent thin film of different materials can be exhibited. These metal thin film and transparent thin film function as the reflective layer 2B, and both can be formed by a vapor phase method such as vapor deposition.

  The material of the reflective layer 2B may be selected by adding a magnetic powder to a transparent synthetic resin having a light refractive index different from that of the light diffraction structure forming layer 2A. In this case, the reflective layer 2B can be formed on the back surface of the light diffraction structure forming layer 2A using, for example, offset printing.

As described above, the thermal recording medium 1 exhibits magnetism by including a magnetic material in the reflective layer 2B. The heat-sensitive recording medium 1 can determine authenticity by detecting this magnetism using a measuring instrument or the like. Moreover, the thermal recording medium 1 can read magnetic information using a magnetic card reader etc. by recording the magnetic information which can be read in a machine on the reflection layer 2B.
Further, as will be described later, the thermal recording medium 1 is formed by laminating an optical diffraction structure forming layer 2A and a reflective layer 2B with an OP layer or the like, and shielding the optical diffraction structure forming layer 2A and the reflective layer 2B from the outside. The forgery prevention effect can be improved.

As the synthetic resin constituting the light diffraction structure layer 2, it is desirable to select and use a hard resin having excellent wear resistance and contamination resistance. However, these synthetic resins have the ability to form holograms and the like. Therefore, an OP layer (not shown), which is a transparent protective layer, is laminated on the upper surface of the light diffraction structure layer 2 as a separate layer as necessary in order to further enhance the strength. It is preferable. Further, by providing the OP layer, the slipperiness of the surface is improved, so that the wear resistance can be improved.
As the resin for forming the OP layer, a thermoplastic resin may be used, but a thermosetting resin composition using a thermosetting resin, or an ionizing radiation curable resin composition that is cured by ultraviolet ray or electron beam irradiation, etc. The physical and chemical performances can be further improved by using the above curable compound and heating after coating, or by irradiating with ionizing radiation and crosslinking curing. The thickness of the OP layer is preferably about 2 μm because of the enhancement of the protective function and the desire to reduce the thickness. As the ionizing radiation curable resin composition, a prepolymer, an oligomer and / or a monomer having a polymerizable unsaturated bond or an epoxy group in the molecule are appropriately mixed. The ionizing radiation refers to an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing or cross-linking molecules, and usually an ultraviolet ray or an electron beam is used.

  Examples of prepolymers and oligomers in the ionizing radiation curable resin composition include unsaturated polyesters such as unsaturated dicarboxylic acid and polyhydric alcohol condensates, polyester methacrylate, polyether methacrylate, polyol methacrylate, melamine methacrylate, etc. Examples include methacrylates, polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polyol acrylates, acrylates such as melamine acrylate, and cationic polymerization type epoxy compounds. These prepolymers and oligomers are used in combination with one or more polyfunctional monomers or monofunctional monomers as necessary. In order to give ordinary application suitability to ionizing radiation curable resin compositions The prepolymer or oligomer is preferably 5% by weight or more, and the monomer and / or polythiol compound is preferably 95% by weight or less.

  When flexibility is required when an ionizing radiation curable resin composition is applied and cured, it is preferable to reduce the amount of monomer or use an acrylate monomer having 1 or 2 functional groups. When wear resistance, heat resistance, and solvent resistance are required when an ionizing radiation curable resin composition is applied and cured, ionizing radiation such as using an acrylate monomer with three or more functional groups A curable resin composition can be designed. Here, examples of the functional group having 1 include 2-hydroxy acrylate, 2-hexyl acrylate, and phenoxyethyl acrylate. Examples of the functional group having 2 include ethylene glycol diacrylate and 1,6-hexanediol diacrylate. Examples of the functional group having 3 or more include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate.

  When hardening after application | coating of an ionizing radiation curable resin composition is performed by ultraviolet irradiation, a photoinitiator and a photoinitiator are added. As the photopolymerization initiator, in the case of a resin system having a radical polymerizable unsaturated group, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether and the like are used alone or in combination. In the case of a resin system having a cationic polymerizable functional group, an aromatic diazonium salt, an aromatic sulfonium salt, an aromatic iodonium salt, a metatheron compound, a benzoin sulfonic acid ester or the like is used alone or as a mixture as a photopolymerization initiator. . The addition amount of a photoinitiator is 0.1-10 weight part with respect to 100 weight part of ionizing radiation-curable resin compositions.

  In order to form the light diffraction structure forming layer 2A, after applying to an appropriate application target, a hologram or diffraction grating pattern is formed using a replication mold having fine irregularities on the mold surface to give a hologram or diffraction grating pattern. After shaping, after shaping, if it is a curable resin, cure by taking a curing means, and when using a photosensitive resin composition, develop with an appropriate developer, By revealing fine irregularities. Thereby, since the pattern and hue change according to the viewing angle, the optical diffraction structure layer 2 can identify the authenticity of the thermal recording medium 1 and can prevent forgery by a copying machine or the like. it can.

As described above, in the light diffraction structure layer 2, the reflection layer 2B is formed of a material containing a magnetic material. For this reason, since the thermal recording medium 1 (light diffraction sheet) exhibits magnetism, the authenticity of the thermal recording medium 1 can be determined by using a measuring device or the like that detects the magnetism.
Further, by reading and writing information on the reflective layer 2B using a magnetic card reader / writer, it can be used as a magnetic recording unit. Since this magnetic recording portion is provided in the reflective layer 2B and shielded from the outside, the effect of preventing forgery can be improved.
Furthermore, since the pattern and hue of the light diffraction structure layer 2 change according to the viewing angle, forgery by a copying machine or the like can be prevented.

  The heat-sensitive recording layer 3 is formed from a material that develops color when heated, and is printed using a thermal printer or the like. The thermosensitive recording layer 3 is composed of, for example, an electron donating dye precursor and an electron accepting compound as main components. As the electron-donating dye precursor, any leuco dye that is applied to this kind of heat-sensitive material is arbitrarily applied, and it can be applied to yellow, magenta, cyan, or other hue systems depending on the application. A color is selected. For example, leuco compounds such as triphenylmethane, fluorane, phenothiazine, auramine, spiropyran, and indinophthalide are preferably used.

  The electron-accepting compound is used as a developer in combination with an electron-donating dye precursor, and specifically includes the following acidic substances. That is, phenolic substances such as bisphenol A, octylphosphonic acid, nonylphosphonic acid, decylphosphonic acid, dodecylphosphonic acid, tetradecylphosphonic acid, hexadecylphosphonic acid, octadecylphosphonic acid, eicosylphosphonic acid, etc., α-hydroxy Organic acids such as octanoic acid, α-hydroxydodecanoic acid, α-hydroxytetradecanoic acid, α-hydroxyhexadecanoic acid, or α-hydroxyoctadecanoic acid, metal complex compounds, thio Diphenylurea or quinones.

  The electron-donating dye precursor and the electron-accepting compound are dispersed in a binder resin to constitute the heat-sensitive recording layer 3. Binder resins include starches, celluloses, gelatin, casein, polyvinyl alcohols, maleic anhydride copolymers, acrylics, styrene / butadiene copolymer emulsions, urea resins, melamine resins, amide resins, polyurethane resins, etc. As necessary, various auxiliary agents such as polyethylene wax or glyoxal as an antifoaming agent, stearic acid amide, behenic acid amide, methylenebisstearic acid amide, dibenzyl oxalate, or tolyl as a sensitizer. Biphenyl ether or the like, or a pigment such as kaolin, clay, calcium carbonate, titanium oxide, styrene, or silica. The heat-sensitive recording layer 3 made of the above materials is usually a colorless, transparent or slightly haze layer. However, as long as the thickness is not excessive, it does not impair the transparency and has transparency in that sense. . That is, the hologram or the like of the light diffraction structure layer 2 formed on the back surface of the thermosensitive recording layer 3 can be visually recognized.

  When two or more thermosensitive recording layers 3 are provided, the materials constituting the layers can be selected so that the coloring hues of the layers are different, and two or more colors can be developed. When two or more heat-sensitive recording layers 3 are provided, the material constituting the heat-sensitive recording layer 3 is selected and formed so that the energy required for each layer to develop color differs. When the thermal recording layer 3 is laminated as two or more layers in contact with each other, for example, the thermal recording layer 3 is already provided based on the action of the solvent in the ink used to form the thermal recording layer to be provided later. Since the electron donating dye precursor and the electron accepting compound in the heat sensitive recording layer may react and develop color, the two or more different heat sensitive recording layers or between other layers and the heat sensitive recording layer May be provided with an intermediate layer made of a resin or the like for the purpose of separating the layers. By providing an intermediate layer, it is possible to create a difference in energy required for each of two or more different thermosensitive recording layers to develop a color, that is, to create an energy gap. The boundary when the layer is colored can be clarified, that is, the contrast can be clarified.

FIG. 2A is a diagram showing a thermal recording medium label 4 to which the present invention is applied.
As shown in FIG. 2A, the heat-sensitive recording medium label 4 has a light diffraction structure layer 2 and a heat-sensitive recording layer 3 (that is, a heat-sensitive recording medium 1 (light diffraction sheet)) on the surface of the sheet-like substrate 5. The protective layer 7 is laminated | stacked in order, and the adhesive bond layer 6 is laminated | stacked on the back surface of the sheet-like base material 5. FIG. That is, the thermosensitive recording medium label 4 is laminated on the back side of the thermosensitive recording layer 3 and the light diffraction structure layer 2 and on the back side of the sheet-like substrate 5, and the target article (cover) Since it is provided with an adhesive layer 6 (adhesive layer) that can be attached to an adhesive body, it is a thermal recording medium that can be used as a label.
The sheet-like substrate 5 is preferably present as an object to be formed when forming the light diffraction structure layer 2 or the heat-sensitive recording layer 3, or in the sense of imparting mechanical strength to the heat-sensitive recording medium label 4. You can also The protective layer 7 is for increasing the durability after the heat-sensitive recording medium label 4 is applied to the target article using the adhesive layer 6, but can also be omitted.
Further, as shown in FIG. 2B, the light diffraction structure layer 2 and the heat-sensitive recording layer 3 in the heat-sensitive recording medium label 4 are sheet-like, contrary to the case described with reference to FIG. The heat-sensitive recording layer 3 and the light diffraction structure layer 2 may be laminated in this order from the substrate 5 side.
When the sheet-like substrate 5 is transparent, the sheet-like substrate 5 is the uppermost layer, and the sheet-like substrate 5, the thermal recording layer 3, the light diffraction structure layer 2, and the adhesive layer 6 are arranged in this order from the upper side. You may laminate | stack, and the protective layer 7 may be laminated | stacked on the upper side of the sheet-like base material 5 in that case. Of course, the sheet-like substrate 5 may be the uppermost layer, and the sheet-like substrate 5, the light diffraction structure layer 2, the thermosensitive recording layer 3, and the adhesive layer 6 may be laminated in this order from the upper side. A protective layer 7 may be laminated on the upper side of the material 5.

FIG. 2C is a diagram showing a thermal recording medium transfer sheet 8 to which the present invention is applied.
In FIG.2 (c), the protective layer 7 is laminated | stacked on the back surface of the sheet-like base material 5 so that peeling is possible, and also the thermal recording layer 3 and the optical diffraction structure layer 2 (namely, thermal recording medium 1 (optical diffraction sheet)). ), The adhesive layer 6 is laminated in order. That is, the heat-sensitive recording medium transfer sheet 8 is laminated on the back side of the heat-sensitive recording layer 3 and the light diffraction structure layer 2, and an adhesive layer 6 (adhesive layer) that can be attached to the target article (adhered body). And a sheet-like base material 5 which is laminated on the surface side of the heat-sensitive recording layer 3 and the light diffraction structure layer 2 and is provided so as to be peelable, so that it can be used as a transfer sheet. It is a medium.
The adhesive layer 6 can be omitted from the thermal recording medium transfer sheet 8 as long as the adhesive layer is formed on the surface of the target article during transfer. Moreover, although the protective layer 7 is for increasing the durability of the surface after performing transfer to the target article using the adhesive layer 6, it can also be omitted.
Further, as shown in FIG. 2D, the light diffraction structure layer 2 and the heat sensitive recording layer 3 in the heat sensitive recording medium transfer sheet 8 are formed from the light diffraction structure layer 2 and the heat sensitive recording layer 3 from the sheet-like substrate 5 side. It may be laminated in order. Also in this case, the adhesive layer 6 and the protective layer 7 can be omitted.

  As described with reference to FIGS. 2A to 2D, in the thermal recording medium label 4 and the thermal recording medium transfer sheet 8, the order of stacking the light diffraction structure layer 2 and the thermal recording layer 3 is arbitrary. Good. Further, an adhesive layer can be interposed between the respective layers as required.

  The sheet-like base material 5 is preferably used as a formation target when forming the light diffraction structure layer 2 and the heat-sensitive recording layer 3, and preferably has the meaning of imparting mechanical strength to the heat-sensitive recording medium transfer sheet 8. You can also

  As the sheet-like base material 5, it is possible to reduce the thickness, and it is preferable to have a solvent resistance and a heat resistance that can withstand processing when manufacturing a mechanical strength and authenticity determination medium. Since it depends on the purpose of use, it is not limited, but a film-like or sheet-like plastic is preferable. Examples include various plastic films or plastic sheets such as polyethylene terephthalate (PET), polycarbonate, polyvinyl alcohol, polysulfone, polyethylene, polypropylene, polystyrene, polyarylate, triacetyl cellulose (TAC), diacetyl cellulose, polyethylene / vinyl alcohol, etc. can do.

  The adhesive layer 6 is used to apply a thermal recording medium label 4, a thermal recording medium transfer sheet 8, and the like having the light diffraction structure layer 2, the thermal recording layer 3 (that is, the thermal recording medium 1), and the like to a target article. As the adhesive constituting the adhesive layer 6, a heat sensitive adhesive or a pressure sensitive adhesive can be used. In the case of the thermal recording medium label 4, a pressure sensitive adhesive that can be attached only by pressure is often used, and in the case of the thermal recording medium transfer sheet 8, it can be instantly transferred by heat and pressure. In this sense, a heat-sensitive adhesive is often used.

  In addition to general protection of the light diffraction structure layer 2 and the heat-sensitive recording layer 3, the protective layer 7 prevents surface deformation due to heat and pressure caused when recording on the heat-sensitive recording layer 3, and is resistant to chemicals. In addition to improving the property, water resistance, friction resistance, head matching properties, etc., it is also used for the purpose of improving transparency. As a material constituting the protective layer 7, a resin composition having desired physical properties as the surface protective layer is selected from those already mentioned as the binder resin constituting the thermosensitive recording layer 3. In particular, when surface scratch resistance, chemical resistance, and contamination resistance are required, a thermosetting resin, or an ionizing radiation curable resin such as an ultraviolet curable resin or an electron beam curable resin is usually used. In order to smoothly move the thermal recording medium label 4, the thermal recording medium transfer sheet 8, and the thermal head during recording on the thermal recording layer 3, the protective layer 7 has releasability. Preferably it is. For this reason, it is preferable to mix a release material such as silicone in the protective layer 7 or to coat the surface of the protective layer with a material containing the release material. The protective layer 7 is also required to have both printability and slipperiness since printing using a thermal transfer ribbon may be performed so that unauthorized rewriting cannot be performed after the thermal recording medium is used. Sometimes. In this case, after a layer having printability is first formed, a material including a releasable substance is used, for example, a point having a diameter of about 0.1 mm and a line having a width of about 0.1 mm are set to 0. By arranging the portions having the releasability and the portions having the printability by arranging them at intervals of about 2 mm or more, it is possible to have both properties.

  In the thermal recording medium transfer sheet 8, it is preferable that the thermal recording medium 1 is detachably laminated with the sheet-like substrate 5. When the protective layer 7 and other layers are present, it is only necessary to ensure releasability between the sheet-like substrate 5 and the layer in contact with the sheet-like substrate 5. Even if it is said to be peelable, an adhesive strength that does not peel is required until just before transfer. When a PET film is used as the sheet-like substrate 5, most of the binder resin in the paint or ink does not adhere firmly to the PET film and can be peeled off during transfer. If necessary, a binder resin having high adhesiveness may be added to increase the peel strength, or a peelable binder resin or material such as wax may be added to lower the peel strength.

  FIG. 3 is a diagram showing one embodiment of the thermal recording medium 9 of the present invention. As shown in FIG. 3A, the heat-sensitive recording medium 9 is a laminated structure including a light diffraction structure layer 2, a heat-sensitive recording layer 3 (that is, heat-sensitive recording medium 1 (light diffraction sheet)), and a protective layer 7 from the lower side. The substrate is laminated on the substrate 10 so that the reflective layer 2B side is in contact therewith, and the magnetic recording layer 11 is laminated on the lower surface side of the substrate 10. As shown in FIG. 3B, the heat-sensitive recording medium 9 includes the heat-sensitive recording layer 3, the light diffraction structure layer 2 (that is, the heat-sensitive recording medium 1 (light diffraction sheet)), and the protective layer 7 from the lower side. The laminated body may be laminated on the base material 10 so that the heat-sensitive recording layer 3 side is in contact therewith, and the magnetic recording layer 11 may be laminated on the lower surface side of the base material 10.

  In the case where the thermal recording layer 3 of the thermal recording medium 9 as shown in FIG. 3B is subjected to thermal recording, the portion (= recording portion) colored by the recording of the thermal recording layer 3 is more than the thermal recording layer 3. Due to the action of the light diffraction structure layer 2 laminated on the top, an effect is produced in which the color of the recording portion appears to change when viewed from the upper surface side of the figure. For example, when the heat-sensitive recording layer 3 has two layers for black color development and red color development, by performing thermal recording, the recording part colored in red and the recording part colored in black are not colored. A solid visual part is produced, but a complicated visual effect is produced in which the color changes on the recording part colored in red, on the recording part colored in black, and on the plain part not colored. In this way, it is possible to make it difficult to counterfeit or to counterfeit a thing with a complicated visual effect, and it is possible to suppress copying using a color copier.

FIG. 4 is a diagram showing a thermal recording medium 9 which is one embodiment of the present invention.
The heat-sensitive recording medium 9 includes a magnetic recording layer 11, a base material 10, an intermediate layer 12A, a heat-sensitive recording layer A (reference 3A), an intermediate layer 12B, a heat-sensitive recording layer B (reference 3B), a light diffraction structure layer 2, from the lower surface side. And the protective layer 7 is laminated | stacked. The role of the intermediate layer B (reference numeral 12B) is as described above, but the role of the intermediate layer A is to prevent the thermal recording layer A from developing color when the substrate 10 and the thermal recording layer A are laminated. This is to thermally cut off between the material 10 and the heat-sensitive recording layer A.

  The laminate composed of the base material 10 and the magnetic recording layer 11 is widely used for various cards such as credit cards or savings cards, transportation commuter passes, identification cards, etc. The magnetic recording layer 11 Various information is recorded as invisible information, the recorded information is read using reading means, and predetermined steps are executed to settle the purchase price, deposit or withdraw cash, or pass through the gate , Etc. are performed.

  The base material 10 has strength and thickness according to the application, and is made of the same plastic film or plastic sheet as the material constituting the sheet-like base material 5 or paper, and if necessary, 2 -3 sheets or more may be combined.

  The magnetic recording layer 11 is (1) provided by directly applying to a base material 10 using a magnetic paint prepared by adding a material containing magnetic powder and kneading. (2) What is the base material 10? Applied to another thin plastic film, etc., cut into stripes and attached to the card substrate 10, or (3) Magnetic recording layer transfer prepared by being peelably laminated on a temporary substrate The sheet is formed by being transferred to the base material 10 by a transfer method. The magnetic recording layer 11 is formed as a thin film of a magnetic substance in a gas phase by vapor deposition or sputtering of the magnetic substance on the base material 10, or the formation of such a thin film is a base of a magnetic recording medium. It may be performed on a base material different from the material, and then cut and pasted into a stripe shape or applied by transfer.

  In the thermal recording 3 of the thermal recording medium 9, for example, information such as the name and number of each owner, the valid period, the boarding section, or the amount of money is recorded as visual information, and it is configured so that visual determination is possible. ing.

  Further, since the light diffraction structure layer 2 of the thermal recording medium 9 in the above example has an effect of changing the hue depending on the viewing angle, it gives an impression that reproduction by color copying is difficult, and an effect of preventing forgery occurs.

  In the heat-sensitive recording medium 9 of the above example, the magnetic recording layer 11 is provided as the information recording means on the base material 10. However, the magnetic recording layer 11 may be replaced with an IC chip, or the magnetic recording layer 11 And an IC chip may be provided.

  In the thermal recording medium 9 of the present invention, in addition to the visual information recording performed using the thermal recording layer 3, the name of the issuing organization, the name of the card, the cautionary note, the explanatory note, the amount for use as a voucher, etc. Information, an arbitrary pattern, or a color pattern may be provided. The information, the pattern, or the color pattern may be formed by an arbitrary means such as printing, and a portion to be formed includes the thermal recording layer 3. Any part may be used as long as it does not interfere with recording on the recording medium, and any part of the thermal recording medium 1, the thermal recording medium label 4, or the thermal recording medium transfer sheet 8 described above may be used. Good.

Next, Example 2 of the optical diffraction sheet to which the present invention is applied will be described.
The light diffraction sheet of Example 2 is a heat-sensitive recording medium in which a reflective layer is partially patterned on the back surface of the light diffraction structure forming layer. Note that portions that perform the same functions as those of the above-described thermal recording medium 9 and the like are denoted by the same reference numerals, redundant description is omitted appropriately, and changes are mainly described. Further, the surface on which the print recorded on the heat-sensitive recording medium and the hologram recorded on the light diffraction structure forming layer can be visually recognized is defined as the front surface, and the opposite surface is defined as the back surface. To do.
FIG. 5 is a cross-sectional view showing the thermal recording medium 100 (light diffraction sheet) on which the light diffraction structure layer 20 is laminated.
As shown in FIG. 5, the thermal recording medium 100 includes a protective layer 7, a thermal recording layer 3, a base material 10, a magnetic recording layer 11 (described above), a light diffraction structure forming layer 20A, and a pattern reflection layer 20B. The optical diffraction structure layer 20 comprised from these, and the contact bonding layer 30 are provided.
The heat-sensitive recording medium 100 is formed so that an effect such as a hologram is positively exhibited only in a range where the pattern reflection layer 20B exists. Further, as described later, the thermal recording medium 100 uses a material having a refractive index equivalent to that of the optical diffraction structure forming layer 20A as the adhesive layer 30, so that the adhesive layer 30 and the optical diffraction structure formation layer 20A are In a direct contact range (that is, a range where the pattern reflection layer 20B does not exist), the effect of a hologram or the like can be almost eliminated. Hereinafter, each layer of the thermal recording medium 100 will be described in detail.

As shown in FIG. 5, the light diffractive structure layer 20 includes a light diffractive structure forming layer 20A having a hologram or diffraction grating pattern applied to the entire surface, and a pattern reflecting layer 20B provided by patterning a predetermined pattern on the back surface thereof. It consists of.
For the light diffraction structure forming layer 20A, various resin materials such as a thermosetting resin, a thermoplastic resin, and an ionizing radiation curable resin can be selected. Examples of the thermosetting resin include unsaturated polyester resins, acrylic urethane resins, epoxy-modified acrylic resins, epoxy-modified unsaturated polyester resins, alkyd resins, and phenol resins. Examples of the thermoplastic resin include acrylate resin, acrylamide resin, nitrocellulose resin, and polystyrene resin. These resins are used alone or as a copolymer of two or more. These resins may be used alone or in combination of two or more kinds of isocyanate resins, metal soaps such as cobalt naphthenate and zinc naphthenate, peroxides such as benzoyl peroxide and methyl ethyl ketone peroxide, benzophenone, acetophenone, anthraquinone, naphthoquinone, A heat or ultraviolet curing agent such as azobisisobutyronitrile or diphenyl sulfide may be blended. Examples of the ionizing radiation curable resin include epoxy acrylate, urethane acrylate, and acrylic-modified polyester. Other monofunctional or polyfunctional monomers, oligomers and the like can be conjugated to such an ionizing radiation curable resin for the purpose of adjusting the cross-linked structure and viscosity.

The pattern reflection layer 20B is a layer for reflecting all or part of the light beam that has passed through the light diffraction structure forming layer 20A. In the present embodiment, the pattern reflection layer 20B is formed of a material in which a magnetic material is contained in a metal or a resin, which will be described later, so that the thermal recording medium 1 exhibits magnetism.
When the amount of light rays reflected by the pattern reflection layer 20B is large, the light diffraction structure layer 20 becomes an opaque type hologram. When the amount of light rays passing therethrough is large, the light diffraction structure layer 20 becomes a transparent type hologram. . Here, the opaque type hologram means a hologram whose back side layer is less visible than the hologram part, while the transparent type hologram means a hologram whose back side layer is more easily visible than the hologram part. . That is, for example, when there is a printed layer or the like on the back side of the hologram, the opaque type cannot confirm the printed content from the front surface, whereas the transparent type visually recognizes the printed content or the like. be able to. The pattern reflection layer 20B can be formed by a method such as sublimation, vacuum deposition, sputtering, reactive sputtering, ion plating, or electroplating.

  When the light diffraction structure layer 20 is formed into an opaque type hologram, the pattern reflection layer 20B is formed thick to increase the amount of reflected light. In this case, the pattern reflection layer 20B is made of, for example, Al, Cr, Ti, Fe, Co, Ni, Cu, Ag, Au, Ge, Mg, Sb, Pb, Cd, Bi, Sn, Se, In, Ga, Rb. These are formed from a material in which a magnetic powder is contained in a single or a combination of two or more of such metals, oxides thereof, nitrogen compounds, and the like. Among the above metal thin films, Al, Cr, Ni, Ag, Au and the like are particularly preferable, and the film thickness is in the range of 1 to 10,000 nm, desirably 2 to 200 nm.

On the other hand, when the light diffraction structure layer 20 is formed into a transparent type hologram, a transparent material having a large refractive index difference is used for the pattern reflection layer 20B, or a large amount of light passes through using a metal thin film. To do.
When a transparent substance is used for the pattern reflection layer 20B, the pattern reflection layer 20B is formed by using a transparent resin material having a refractive index different from that of the light diffraction structure forming layer (photocuring resin layer) 20A and containing magnetic powder. The refractive index of the transparent resin material may be larger or smaller than the refractive index of the resin of the light diffraction structure forming layer 20A, but the difference in refractive index is preferably 0.1 or more, more preferably 0.5 or more. Preferably, 1.0 or more is optimal.
In the case where a metallic reflective film other than a transparent resin is used for the pattern reflective layer 20B, it is preferable to form it as thin as 20 nm or less in order to provide light transmittance. Examples of the transparent type reflective layer that can be suitably used include those in which magnetic powder is contained in titanium oxide (TiO ₂ ), zinc sulfide (ZnS), Cu · Al composite metal oxide, and the like.

The pattern reflection layer 20B is formed using, for example, a water washing method, an etching method, or the like.
In the water washing method, water-soluble ink is provided in a pattern on the back surface of the light diffraction structure forming layer 20A, and further, for example, a metal layer is provided using a technique such as vapor deposition. That is, a metal layer is provided by masking the back surface of the light diffraction structure forming layer 20A with water-soluble ink. By washing this with water, only the water-soluble ink and the metal layer provided thereon are removed by washing, and the portion of the metal layer where the water-soluble ink did not exist remains to form the pattern reflection layer 20B. can do.
In the etching method, a metal layer is provided on the entire back surface of the light diffraction structure forming layer 20A, and then a pattern layer (resist layer) is provided with an acid-resistant and alkali-resistant resin for etching. In this case, the pattern reflection layer 20B can be formed by leaving the metal layer in a pattern in a portion where the resist layer exists.
On the other hand, when a material in which a magnetic material powder is included in a synthetic resin is selected as the material of the reflective layer 20B, the reflective layer 20B can be formed using, for example, offset printing.

  The adhesive layer 30 is a layer for adhering the base material 10 and the light diffraction structure layer 20 which are other layers. The adhesive layer 30 is a layer having substantially the same refractive index as that of the light diffraction structure forming layer 20A (hereinafter referred to as “the same refractive index layer”) by selecting one having the same refractive index as that of the light diffraction structure forming layer 20A. Most of the light rays that have passed through the light diffraction structure forming layer 20A can pass therethrough. Thereby, in the range where the adhesive layer 30 (the same refractive index layer) and the optical diffraction structure forming layer 20A are in contact with each other, the effect of the hologram or the like can be almost eliminated. However, also in this range, the hologram or diffraction grating pattern is applied to the entire surface of the light diffraction structure forming layer 20A. Therefore, the heat-sensitive recording medium 100 can confirm a subtle hologram or the like by using a measuring instrument or the like, and can determine authenticity.

FIG. 6 is a diagram showing a part of a thermal recording medium 100A, which is an example of the thermal recording medium 100 described above, from the surface.
The base material 10 of the heat-sensitive recording medium 100A is, for example, white. The thermosensitive recording layer 3 is made of a transparent or translucent material, and a ring is printed by a thermal printer or the like, and the range of the ring is colored, for example, red. The light diffractive structure layer 20 is formed by patterning the letters “DNP” on the light diffractive structure forming layer 20A, and the pattern reflecting layer 20B is formed of a resin material or a metal material containing magnetic powder, and is planar. Patterning is performed so that the shape (the shape seen from the front side) becomes a star (predetermined pattern).

Explaining how the heat-sensitive recording medium 100A appears, the heat-sensitive recording layer 3 is colored in red without lacking the entire range of the ring because no other print layer is formed on the surface side. In the range where “DNP” of the light diffractive structure forming layer 20A is patterned and the star mark of the pattern reflecting layer 20B overlap (indicated by a black area in the figure), the light diffractive structure layer 20 has an effect such as a hologram. Is expressed. On the other hand, in the range where the “DNP” of the light diffraction structure forming layer 20A and the star mark of the pattern reflection layer 20B do not overlap (indicated by the broken line in the figure), the effect of the hologram or the like is almost eliminated by the action of the adhesive layer 30. Like the surrounding area, the surface of the substrate 10 can be visually recognized.
The pattern reflection layer 20B is formed so that the planar shape thereof becomes a star, and the shape of the star can be confirmed from the surface. For this reason, the thermal recording medium 100 </ b> A can obtain the effect of improving the designability in addition to the effect related to magnetism described in the first embodiment.

FIG. 7 is a cross-sectional view showing a thermal recording medium transfer sheet 200 (light diffraction sheet).
The thermal recording medium transfer sheet 200 is a transfer sheet that allows the thermal recording medium 100 to be adhered to an adherend.
The thermal recording medium transfer sheet 200 has a release layer and a sheet-like substrate 5 on the surface of the protective layer 7 (that is, the surface side of the thermal recording layer 3 and the light diffraction structure layer 20) with respect to the thermal recording medium 100. Then, the adhesive layer 30 is laminated on the back surface of the base material 10 (that is, the back surface side of the heat-sensitive recording layer 3 and the light diffraction structure layer 20). Thereby, the thermal recording medium transfer sheet 200 can transfer the thermal recording medium 100 to an adherend.
Note that the base material 10 may be omitted if not necessary, for example, because the mechanical strength of the thermal recording medium transfer sheet 200 is sufficient.
In addition, as shown in FIG. 7, an adhesive layer is provided between the optical diffraction structure layer 20 and the layer in contact with the optical diffraction structure layer 20 (in the case of FIG. 7, the base material 10). It does not have to be provided. In this case, the same effect as described above can be obtained by forming the layer (base material 10) in contact with the light diffraction structure layer 20 from a transparent or translucent material to have the same refractive index. .
Further, the magnetic recording layer 11 may not be provided if it is not necessary.

Thermal recording media 300 to 600 (light diffraction sheets) shown in FIGS. 8 to 11 are sectional views showing an example in which the configuration of the thermal recording medium 100 shown in FIG. 5 is changed.
The thermosensitive recording medium 300 shown in FIG. 8 is provided with two color thermosensitive recording layers 3A and 3B and intermediate layers 12A and 12B with respect to the thermosensitive recording medium 100 so that, for example, black and red can be developed. It is a thing.

A thermal recording medium 400 shown in FIG. 9 is obtained by changing the light diffraction structure layer 20 to the surface side of the thermal recording layers 3A and 3B with respect to the thermal recording medium 300.
In the thermal recording medium 400, an anchor layer 41 is provided between the light diffraction structure layer 20 and the thermal recording layer 3B for adhesion, protection, and the like between the layers. In this case, by making the refractive index of the anchor layer 41 and the optical diffraction structure forming layer 20A substantially the same, the anchor layer 41 functions as a layer having the same refractive index, and a hologram in a range where these two layers are in direct contact with each other. The effects such as can be almost eliminated.
Further, the anchor layer 41 may be deleted when the light diffraction structure layer 20 and the thermosensitive recording layer 3B can be directly joined. In this case as well, the same effect as described above can be obtained by making the refractive index of the light diffraction structure forming layer 20A and the thermal recording layer 3B equal and causing the thermal recording layer 3B to function as the same refractive index layer.
Further, the anchor layer 41 may be deleted when the light diffraction structure layer 20 and the thermosensitive recording layer 3B can be directly joined. In this case as well, the same effect as described above can be obtained by making the refractive index of the light diffraction structure forming layer 20A and the thermal recording layer 3B equal and causing the thermal recording layer 3B to function as the same refractive index layer.
The thermal recording medium 400 is not provided with a protective layer (see the protective layer 7 such as the thermal recording medium 300). This is because the thermal recording medium 400 has no problem with surface damage, dirt adhesion, strength, and the like.

A thermal recording medium 500 shown in FIG. 10 is obtained by providing a printing layer or the like on the front side and the back side of the thermal recording medium 300. A primer 42A is applied to the back side of the magnetic recording layer 11 in order to improve the printing strength of the ink. An explanatory note print layer 43 is provided by using silk printing, offset printing or the like for explaining the usage method of the thermal recording medium 500 (for example, “notes on the use of a commuter pass” for a commuter pass). Further, a protective layer 7A is provided on the back surface side.
On the surface side of the protective layer 7B, a primer 42B and an image receiving layer 44 for improving the printing strength and the like are provided in order, and on the surface thereof, for example, to prevent forgery by copying using a copying machine or the like. A tint block printing layer 45 on which a tint block having a fine pattern is printed is provided by silk printing, offset printing, or the like. A lubrication layer 46 is laminated on the surface of the tint block printing layer 45, and friction between a feeding mechanism such as an inkjet printer or a thermal transfer printer for forming the printing layer 47 and the thermal recording medium 500, an inkjet head and the thermal recording medium 500 Friction etc. are reduced. The print layer 47 is a print layer provided on the surface of the thermal recording medium 500, and “invalid” is printed on a commuter pass whose expiration date has passed, using an inkjet printer, a thermal transfer printer, or the like.

  A thermal recording medium 600 shown in FIG. 11 is provided with an OP layer 48, a printing layer, etc. (descriptive text printing layer 43, tint block printing layer 45, printing layer 47) on the front and back sides of the thermal recording medium 400. . Since the configuration for providing the print layer and the like is the same as that of the thermal recording medium 500, the description thereof is omitted. The OP layer 48 is provided because the strength of the material differs or the adhesiveness with the upper layer differs depending on the type of the light diffraction structure layer 20.

As described above, the thermal recording medium 100A and the like have the pattern reflection layer 20B formed from stars (predetermined patterns). As a result, even if a hologram or diffraction grating pattern is formed on the entire surface of the light diffraction structure forming layer 20A, the effect of the hologram or the like can be expressed only in the range of the pattern reflection layer 20B, and the effect of preventing forgery can be improved. The star can be visually recognized when viewed from the surface.
The thermal recording medium 100 and the like are provided on the back surface of the light diffraction structure forming layer 20A and include the same refractive index layer having substantially the same refractive index as the light diffraction structure forming layer 20A. In the range where the layer having the same refractive index is in direct contact, the effect of a hologram or the like can be almost eliminated.
Further, the heat-sensitive recording medium 300 or the like is transparent or semi-transparent before heating and color development, and the heat-sensitive recording layers 3A and 3B are layers having different colors. For this reason, the hologram, printing, etc. of the layer formed in the back surface side rather than the thermosensitive recording layers 3A and 3B can be visually recognized. In addition, since the recording of characters, symbols, etc. can be performed in two or more colors and a complicated visual effect can be obtained, the effect of preventing forgery of the thermal recording medium can be further improved.
Furthermore, since the predetermined pattern can be confirmed in the range where the pattern reflection layer 20B is provided, the effect of improving the design can be obtained in addition to the effect related to magnetism.

Next, Example 3 of the light diffraction sheet to which the present invention is applied will be described.
The light diffraction sheet of Example 3 is a heat-sensitive recording medium 900 in which a reflective layer (full-surface reflective layer) is further laminated on the entire back surface side of the pattern reflective layer.
FIG. 12 is a cross-sectional view showing the thermal recording medium 900.
As shown in FIG. 12A, in the thermal recording medium 900, the light diffraction structure layer 20A and the pattern reflection layer 20B are laminated on the back surface of the base material 10 which is transparent PET. The pattern reflection layer 20B is an opaque metal thin film in which magnetic powder is contained in aluminum. The pattern reflection layer 20B may be formed to be translucent by forming a thin film thinly (for example, 20 nm or less) according to a design (design) requirement or the like.
In the thermal recording medium 900, as shown in FIG. 12B, the reflective layer 20C (entire reflective layer) and the thermal recording layer 3 are laminated on the entire surface in this order on the back side of the pattern reflective layer 20B.
The reflective layer 20C is a transparent reflective layer formed of titanium oxide (TiO ₂ ) or the like using a technique such as vapor deposition or sputtering, and having a refractive index different from that of the light diffraction structure layer 20A.
As will be described later, the light-sensitive recording layer 3 may be damaged by the heating by a thermal printer or the like in the light diffraction structure layer 20A and the pattern reflection layer 20B. In this case, it is preferable that the heat-sensitive recording layer 3 has a printing range in a range that does not overlap the pattern of the light diffraction structure layer 20A and the pattern reflection layer 20B on the plane. Thereby, damage to the light diffraction structure layer 20A and the pattern reflection layer 20B can be prevented.
It should be noted that a layer similar to that of the first and second embodiments described above can be laminated on the back side of the thermosensitive recording layer 3 (the description is omitted here).

The appearance of the above-described thermal recording medium 900 will be described by taking the thermal recording medium 900A having the same configuration as the thermal recording medium 900 as an example.
FIG. 12C is a plan view showing the thermal recording medium 900A.
In the heat-sensitive recording medium 900A, the pattern reflection layer 20B is formed on the back side of the light diffraction structure forming layer 20A having a star pattern. The pattern reflection layer 20B is formed in a plurality of rectangular shapes having different sizes, and is arranged in a line in a bar code shape in the left-right direction. The thermal recording medium 900A has a reflective layer 20C and a thermal recording layer 3 laminated on the entire back surface thereof. Further, the thermal recording medium 900A is an upper range in the plane of the thermal recording layer, and “ABC-DEFG-HIJK” is formed in a portion that does not overlap the star mark of the light diffraction structure forming layer 20A and the rectangle of the pattern reflection layer 20B. And using a thermal printer.

  In the heat-sensitive recording medium 900A configured as described above, the hologram formed by the pattern reflection layer 20B is within the range where the star mark of the light diffraction structure forming layer 20A and the rectangle of the pattern reflection layer 20B overlap (the hatched area shown in the figure). Such effects are manifested. On the other hand, in the range other than that of the star mark of the light diffraction structure forming layer 20A (the range of the horizontal line shown in the figure), an effect such as a hologram by the reflective layer 20C appears. That is, in the thermal recording medium 900A, since the star mark of the light diffraction structure forming layer 20A has different effects such as holograms depending on the range in the plane, the pattern and hue can be expressed more complicatedly. The effect of prevention can be improved.

  Further, since the thermal recording medium 900A exhibits magnetism because the pattern reflection layer 20B contains magnetic powder, the authenticity can be determined by detecting this magnetism using a measuring instrument or the like. Furthermore, since the pattern reflection layer 20B is formed in a barcode shape, the authenticity of the thermal recording medium 900A can be determined by recognizing this arrangement (picture pattern) using a card reader or the like. . The shape of the pattern reflection layer 20B is not limited to the barcode shape. For example, the pattern reflection layer 20B may be formed in a shape such as a pattern, a symbol, or a figure, and these shapes may be recognized by detecting magnetism using a measuring instrument.

  Further, on the thermal recording medium 900A, a character string or the like is printed using a thermal printer or the like on a portion of the plane of the thermal recording layer 3 that does not overlap the pattern of the light diffraction structure forming layer 20A and the pattern reflection layer 20B. Thereby, the thermal recording medium 900A can prevent damage to the light diffraction structure forming layer 20A and the pattern reflection layer 20B.

  As described above, the heat-sensitive recording medium 900 can make the effect of a hologram or the like appear intricately by laminating the pattern reflective layer 20B formed of a metal thin film and the transparent reflective layer 20C. Authenticity can be determined by detecting the magnetism of the pattern reflection layer 20B with a measuring instrument or the like.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
(1) In Example 2 etc., although the reflective layer showed the example which is a pattern reflective layer which has a predetermined pattern, it is not limited to this. The reflective layer may not have a predetermined pattern. For example, a reflection layer (partial reflection layer) partially provided on the back surface of the light diffraction structure forming layer may be used (see the partial reflection layer 20C shown in FIG. 6).

(2) In each of the examples, the example in which the magnetic material is included is the reflective layer or the pattern reflective layer. However, the present invention is not limited to this. Since the light diffraction sheet only needs to exhibit magnetism, a magnetic material may be included in the light diffraction structure forming layer. Moreover, you may include in both a light diffraction structure formation layer, a reflection layer, or a pattern reflection layer. Furthermore, in the case of Example 3, it may be included in the reflective layer 20C (entire reflective layer). In this case, the optical diffraction sheet exhibits more complicated magnetism by including different magnetic materials in each layer or changing the content of the magnetic material, so that the effect of preventing forgery can be further improved.

(3) In each embodiment, an example of a thermal recording medium having a thermal recording layer has been described, but the present invention is not limited to this. Any optical diffraction sheet exhibiting magnetism may be used, and therefore an optical diffraction sheet without a heat-sensitive recording layer may be used. Also by this, the light diffraction sheet can determine authenticity and prevent forgery by using magnetism.

It is a figure which shows Example 1 of the thermosensitive recording medium to which this invention is applied. It is a figure which shows the form which applies the thermosensitive recording medium of Example 1 to object article. 1 is a diagram showing a heat-sensitive recording medium 9 of Example 1. FIG. 1 is a diagram showing a heat-sensitive recording medium 9 of Example 1. FIG. It is a figure which shows Example 2 of the thermosensitive recording medium to which this invention is applied. It is a figure which shows 100 A of thermosensitive recording media of Example 2 from the surface. 6 is a diagram showing a heat-sensitive recording medium transfer sheet 200 of Example 2. FIG. FIG. 6 is a diagram showing a heat-sensitive recording medium 300 of Example 2. FIG. 6 is a diagram showing a heat-sensitive recording medium 400 of Example 2. FIG. 6 is a diagram showing a heat-sensitive recording medium 500 of Example 2. FIG. 6 is a diagram showing a heat-sensitive recording medium 600 of Example 2. It is a figure which shows Example 3 of the thermosensitive recording medium to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,9 Thermal recording medium 2 Optical diffraction structure layer 2A Optical diffraction structure formation layer 2B Reflective layer 3 Thermal recording layer 4 Thermal recording medium label 5 Sheet-like base material 7 Protective layer 8 Thermal recording medium transfer sheet 10 Base material 11 Magnetic recording layer DESCRIPTION OF SYMBOLS 20 Light diffraction structure layer 20A Light diffraction structure formation layer 20B Pattern reflection layer 30 Adhesive layer 43 Description printing layer 45 Copy-forgery-inhibited pattern printing layer 47 Printing layer 48 OP layer 100,100A, 300-600,900 Thermal recording medium 200 Thermal recording medium transfer Sheet

Claims (13)

A light diffraction structure layer having a hologram or a diffraction grating pattern, and a light diffraction structure layer having a reflection layer provided on the back surface of the light diffraction structure formation layer;
The light diffraction structure forming layer and / or the reflective layer have magnetism;
An optical diffraction sheet characterized by. The light diffraction sheet according to claim 1,
The light diffraction structure forming layer and / or the reflection layer is formed of a material containing a magnetic material;
An optical diffraction sheet characterized by. In the light diffraction sheet according to any one of claims 1 to 2,
The optical diffraction structure forming layer and / or the reflective layer is a magnetic recording unit capable of machine reading;
An optical diffraction sheet characterized by. In the light diffraction sheet according to any one of claims 1 to 3,
The reflective layer has a partially reflective layer partially provided on the back surface of the light diffraction structure forming layer;
An optical diffraction sheet characterized by. The light diffraction sheet according to claim 4,
The partial reflection layer is a pattern reflection layer whose planar shape is formed from a predetermined pattern;
An optical diffraction sheet characterized by. In the light diffraction sheet according to claim 4 or 5,
The reflective layer has a full reflective layer provided on the entire back surface side of the partial reflective layer;
An optical diffraction sheet characterized by. In the light diffraction sheet according to any one of claims 1 to 6,
The reflective layer is transparent or translucent;
An optical diffraction sheet characterized by. In the light diffraction sheet according to any one of claims 1 to 7,
Provided on the back surface of the light diffraction structure forming layer, comprising a refractive index identical layer having substantially the same refractive index as the light diffraction structure formation layer;
An optical diffraction sheet characterized by. In the light diffraction sheet according to any one of claims 1 to 8,
A sheet-like base material laminated on the back side of the light diffraction structure layer; and
An adhesive layer that is laminated on the back side of the sheet-like base material and can be attached to an adherend;
An optical diffraction sheet characterized by. In the light diffraction sheet according to any one of claims 1 to 9,
Laminated on the back side of the light diffraction structure layer, an adhesive layer that can be attached to an adherend, and
Laminated on the surface side of the light diffraction structure layer, and provided with a sheet-like base material provided to be peelable,
The optical diffraction structure layer can be transferred to the adherend;
An optical diffraction sheet characterized by. In the light diffraction sheet according to any one of claims 1 to 10,
Having an image receiving layer for receiving ink;
An optical diffraction sheet characterized by. In the light diffraction sheet according to any one of claims 1 to 11,
Having a tint block printing layer printed with anti-counterfeiting tint blocks;
An optical diffraction sheet characterized by. In the light diffraction sheet according to any one of claims 1 to 12,
Having a thermal recording layer that develops color when heated;
An optical diffraction sheet characterized by.

Images