JP2011115974A - Anti-counterfeit medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-counterfeit medium which has a multi-layered thin film layer to change the reflection color according to change in the visual observation angle and also includes an overt function and an covert function, which, in particular, enables easy visual authenticity check, and makes difficult counterfeit, alteration, falsification, and photocopy. <P>SOLUTION: The anti-counterfeit medium characteristically includes, at least a pattern-like light reflection layer 13 and a phase difference layer 14 to partly or entirely cover the pattern-like light reflection layer, on the multi-layered thin film layer 18 provided on one side of the base material 11, which causes color change in accordance with the visual observation angle under the irradiation of visible light. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an anti-counterfeit medium having a multilayer thin film layer in which a change in reflection color occurs according to a difference in viewing angle, and has both an overt function and a covert function. Further, the present invention relates to a forgery prevention medium that makes forgery, falsification, alteration, and copying difficult.

  Conventionally, as means for preventing counterfeiting, for example, it is difficult to imitate the article itself, or it is difficult to imitate the article itself by attaching it to the article as proof that it is genuine. There is a means to be able to distinguish fake. Typical examples of the latter include anti-counterfeiting means using holograms such as relief holograms and Lippmann holograms that are frequently used in recent years. Among the holograms used here, for example, a relief hologram is a reproduction of interference fringes in the form of fine irregularities, and a unique color shift according to the difference in viewing angle due to light diffraction and interference occurring here. Causes (color change of reflected light). Therefore, by using such a hologram as a means for preventing counterfeiting and confirming the presence or absence of a color shift in that portion, it is possible to easily determine whether or not it is authentic, and authenticity can be easily confirmed. It becomes like this. However, in recent years, the above-described hologram has a simple principle and structure, and since it has become widely known in general, it is becoming easier to forge. It is fading.

  On the other hand, two or more types of plastic films with different refractive indexes are laminated in multiple layers and stretched under certain conditions, as it has the effect of color shift (color change of reflected light) like this hologram. An anti-counterfeiting means using the obtained iris multi-layer film has been proposed (see, for example, Patent Document 1).

  An iris multi-layer film is obtained, for example, by laminating two or more types of plastic films in multiple layers and stretching them under certain conditions so that color shift can be obtained using the interference of light. These have reflection / transmission characteristics in a specific wavelength range, and the reflection / transmission characteristics are changed by changing the observation position so that the visible colors are different. Therefore, whether or not it is genuine by checking the presence or absence of a color shift of the object when it is necessary to carry the iris multi-layer film on a part of the object that is not to be counterfeited and authenticity determination is necessary. Can be easily determined. At this time, since the color change of this iris multi-layer film is difficult to understand if the base material forming the film is a transparent film, a dark colored layer such as black is added as a base of the multi-layer iris film. There is a case.

  The color shift (color change of reflected light) in these holograms and iris multi-layer films makes it possible to determine whether a color change due to a difference in viewing angle is true or false with respect to a forgery, especially using a color copier. When illegal copying is attempted, it is impossible to reproduce such optical characteristics, so that counterfeiting / alteration is difficult, and further, the counterfeiting / alteration is praised.

In order to be able to expect such an effect more, development to a seal | sticker or transfer foil, a transfer sheet, etc. is aimed at recently. For example, a layer made of an iris multi-layer film or a hologram that changes in reflected color in accordance with a change in viewing angle is temporarily supported on a part of the layer, and a formation layer such as an iris multi-layer film or a hologram is pasted. A hologram or the like is formed on a desired article by sticking or transferring to a desired article so as to exhibit the above-described characteristics. In such a case, in order to add even higher security, in particular, the layer structure is taken into consideration, the seal is configured to be difficult to peel off, or the structure is configured to be difficult to regenerate after peeling, such as a brittle seal. If you try to peel it off after it has been pasted, it will destroy part or all of the hologram, making it impossible to counterfeit, and make it possible to determine at a glance that manipulation such as tampering has been applied. ing.

  Furthermore, there is also a forgery prevention medium in which various colors can be seen by applying an emboss of a certain angle to the iris multilayer film by utilizing the color shift effect of the iris multilayer film (see Patent Document 2).

  However, since the iris multilayer film is easily available, it can be easily counterfeited.

JP 2004-333848 A JP 2005-85094 A

  The present invention aims to solve the above-mentioned problems, and has a multilayer thin film layer in which the reflected color changes according to the difference in viewing angle, and has both an overt function and a covert function. An object is to provide a highly forgery-preventing medium.

  In order to achieve the above object, the invention according to claim 1 is characterized in that at least a patterned light reflecting layer is formed on a multilayer thin film layer in which a color change occurs in reflected light corresponding to a viewing angle under irradiation of visible light. And a retardation layer is provided so as to cover a part or the entire surface of the patterned light reflection layer.

  According to the second aspect of the present invention, an optically variable image is displayed on the multilayer thin film layer in which the reflected light undergoes a color change corresponding to the viewing angle under irradiation with visible light, at least by light interference or diffraction. An embossed layer having a minute unevenness on the surface and a patterned light reflecting layer are sequentially provided, and a retardation layer is provided so as to cover a part or the whole of the patterned light reflecting layer. Is a forgery-preventing medium.

  Furthermore, the invention described in claim 3 is an optically variable image based on at least light interference or diffraction on a multilayer thin film layer that causes a color change in reflected light corresponding to a viewing angle under irradiation of visible light. An embossed layer having a fine unevenness on the surface, a patterned light reflecting layer, and a polarizing layer are sequentially provided, and a retardation layer is formed so as to cover a part or the entire surface of the patterned light reflecting layer. An anti-counterfeit medium characterized by being provided.

  Furthermore, the invention according to claim 4 is the forgery prevention medium according to any one of claims 1 to 3, wherein the multilayer thin film layer is provided on one surface side of the substrate. .

  Furthermore, the invention according to claim 5 is the forgery prevention medium according to claim 4, wherein a light absorption layer is further provided on the other surface side of the substrate.

  Furthermore, in the invention described in claim 6, at least a patterned light absorption layer and a reflective layer are sequentially formed on a multilayer thin film layer in which a color change occurs in reflected light corresponding to a viewing angle under irradiation of visible light. An anti-counterfeit medium characterized by being provided.

  Furthermore, the invention described in claim 7 is a method for forming an optically variable image at least by interference or diffraction of light on a multilayer thin film layer in which a color change occurs in reflected light corresponding to a viewing angle under visible light irradiation. An anti-counterfeit medium characterized in that an embossed layer, a patterned light absorbing layer, and a reflective layer having minute irregularities on the surface for enabling display are sequentially provided.

  The invention according to claim 8 is the forgery prevention medium according to claim 6 or 7, wherein the multilayer thin film layer is provided on one surface side of the substrate.

  Furthermore, the invention according to claim 9 is the forgery prevention medium according to claim 8, characterized in that a retardation layer is provided on a part or the whole of the other surface side of the substrate. .

  Furthermore, the invention according to claim 10 is the anti-counterfeit medium according to claim 8 or 9, wherein a polarizing layer is provided on the other surface side of the substrate, and a part or the entire surface of the polarizing layer is further provided. A retardation layer is sequentially provided.

  Furthermore, the invention described in claim 11 is the anti-counterfeit medium according to any one of claims 1 to 4, 9 and 10, wherein the optical axis of the retardation layer is oriented in at least biaxial direction. It is characterized by being.

  Furthermore, the invention described in claim 12 is characterized in that in the anti-counterfeit medium described in any one of claims 1 to 11, an adhesive layer or an adhesive layer is further provided on one surface side.

  Furthermore, the invention described in claim 13 is characterized in that in the forgery prevention medium described in claim 12, a notch and / or a perforation is further provided in part.

  Since the present invention is configured as described above, a color shift (color change of reflected light) can be visually recognized due to a difference in viewing angle, and it has both an overt function and a covert function. This makes it possible to make the pattern appear and be visible, thereby ensuring authenticity verification.

It is explanatory drawing which shows the general | schematic cross-section structure of the forgery prevention medium of this invention. It is explanatory drawing which shows the general planar state of the other forgery prevention medium of this invention. FIG. 3 is an explanatory diagram showing a state when the forgery prevention medium shown in FIG. 2 is being verified. It is explanatory drawing which shows the general | schematic cross-section structure of the other forgery prevention medium of this invention. It is explanatory drawing which shows the general | schematic cross-section structure of the other forgery prevention medium of this invention. It is explanatory drawing which shows the general | schematic cross-section structure of the other forgery prevention medium of this invention.

  Embodiments of a forgery prevention medium according to the present invention will be described below in detail with reference to the drawings.

The anti-counterfeit medium shown in FIG. 1 is provided with a multilayer thin film layer 18 in which a color change occurs in reflected light corresponding to a viewing angle under irradiation of visible light on a base material 11, and further, light interference and An embossing layer having minute unevenness on the surface that enables display of an optically variable image by diffraction, for example, an embossing layer 12 having minute unevenness related to a relief hologram that causes a color change in reflected light on the surface is provided. ing. Further, a patterned light reflecting layer 13 having a predetermined shape and a retardation layer 14 are sequentially provided on the embossed layer 12. And in order to make the color shift in the multilayer thin film layer 18 more effective, the absorption layer 15 is provided on the other surface side of the base material 11. In the figure, reference numeral 17 denotes an adhesive layer.

  In addition, the anti-counterfeit structure shown in FIG. 4 is provided with a multilayer thin film layer 48 in which a color change occurs in reflected light corresponding to a viewing angle under irradiation of visible light on the base material 41, and further, light interference and An embossed layer 42 having minute irregularities on the surface that enables display of an optically variable image by diffraction is provided. Further thereon, a patterned light reflecting layer 43 having a predetermined shape, a polarizing layer 46, and a retardation layer 44 are sequentially provided. And in order to make the color shift of the multilayer thin film layer 48 more effective, an absorption layer 45 is provided on one surface side of the base material 41. In the figure, 47 indicates an adhesive layer.

  Furthermore, the anti-counterfeit structure shown in FIG. 5 is provided with a multilayer thin film layer 58 in which the reflected light undergoes a color change corresponding to the viewing angle under irradiation of visible light on the substrate 51, and the multilayer A patterned light absorption layer 55 having a predetermined shape is provided on the thin film layer 58, and an embossed layer 52 having minute irregularities on the surface that enables display of an optically variable image by light interference or diffraction, and a reflection A layer 53 and an adhesive layer 57 are sequentially provided. A phase difference layer 54 is provided on the other surface side of the substrate 51.

  The anti-counterfeit structure shown in FIG. 6 is provided with a multilayer thin film layer 68 in which the reflected light undergoes a color change corresponding to the viewing angle under irradiation of visible light on the substrate 61, and the multilayer thin film A patterned light absorption layer 65 having a predetermined shape is provided on the layer 68, and further, an emboss layer 62 having fine irregularities on its surface that enables display of an optically variable image by light interference or diffraction, and a reflective layer 63 and an adhesive layer 67 are sequentially provided. On the other surface side of the substrate 61, a polarizing layer 66 and a retardation layer 54 are sequentially provided.

  On the other hand, FIG. 2 shows a state when the forgery prevention medium of the present invention is observed from the front. This anti-counterfeit medium has retardation layers 21 and 22 having an alignment axis in two axial directions and provided in a predetermined pattern shape, but the presence cannot be confirmed visually. Moreover, the reflective layer 23 can be confirmed visually, and the reflective color of the multilayer thin film layer located in the lower layer is observed in the part without a reflective layer. When the anti-counterfeit medium having such a configuration is observed using a verification machine (polarizer), the phase difference layers 21 and 22 provided in a pattern form reflect on the lower layer as shown in FIG. Only the part corresponding to the place where the layer 23 exists can be confirmed.

  When the anti-counterfeit media shown in FIGS. 1, 3, 4, 5 and 6 are also observed using a verifier (polarizer), the phase of natural light that has passed through the polarizer and is polarized is different in the phase difference layer. The phase is shifted and reflected by the reflective layer, and the phase is shifted and returned. However, the portion without the phase difference layer returns as it is from the reflective layer. Then, when passing through the polarizer again, one polarized light is transmitted and the other polarized light is blocked, so that a difference occurs in contrast so that a latent image corresponding to the formation pattern of the retardation layer can be visually recognized. become.

  As the base materials 11, 41, 51, 61 constituting a part of the anti-counterfeit medium having such a configuration, an unstretched film produced by extrusion or casting, a stretched film produced by stretching, or the like is used. be able to.

  The stretched film includes a uniaxially stretched film and a biaxially stretched film depending on how to stretch, but any of them can be used. The stretched film and non-stretched film are made of cellophane, polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyolefin (PO), ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVA), poly Examples thereof include vinyl chloride, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), nylon, acrylic resin, and triacetyl cellulose (TAC).

  On the other hand, as the multilayer thin film layers 18, 48, 58, 68 in which the reflected light undergoes a color change corresponding to the viewing angle under irradiation with visible light, for example, two or more kinds of plastic films having different refractive indexes are laminated in a multilayer. Thus, it is possible to use an iris multilayer film formed by stretching under certain conditions. When the above-mentioned base material is composed of an iris multi-layer film having such a configuration, it is necessary to further provide a multi-layer thin film layer that causes a color change in reflected light corresponding to the viewing angle under irradiation of visible light. Absent.

  As the multilayer thin film layer, for example, a high refractive index material having a refractive index of about 2 or more and a refractive index of about 1.5 are provided on the base material 11, 41, 51, 61 as described above. It may be a multilayer thin film in which a low refractive index material is laminated with a predetermined film thickness.

Examples of the high refractive index material include Sb ₂ O ₃ (3.0 = refractive index n: the same applies hereinafter), Fe ₂ O ₃ (2.7), TiO ₂ (2.6), CdS (2. 6), CeO ₂ (2.3), ZnS (2.3), PbCl ₂ (2.3), CdO (2.2), WO ₃ (2.0), SiO (2.0), Si ₂ O ₃ (2.5), In ₂ O ₃ (2.0), PbO (2.6), Ta ₂ O ₃ (2.4), ZnO (2.1), ZrO ₂ (2.0), etc. Can be used.

As the low refractive index _{material, MgO (1.6), SiO 2} (1.5), MgF 2 (1.4), CeF 3 (1.6), CaF 2 (1.3~1.4 ), AlF ₃ (1.6), Al ₂ O ₃ (1.6), etc. can be used.

  By selecting at least one of these high-refractive index materials and low-refractive index materials and alternately laminating thin films having a predetermined thickness, the visible light of a specific wavelength is absorbed or reflected, and the visible light is irradiated. A multilayer thin film layer that causes a color change in reflected light corresponding to the viewing angle can be obtained below. In addition, as such a multilayer thin film layer, a three-layer configuration of a high refractive index layer, a low refractive index layer and a high refractive index layer, or a low refractive index layer and a high refractive index in the three-layer configuration is used. An odd-numbered layer structure in which both ends are high-refractive index layers, such as a five-layer structure in which layers are stacked, is preferably used because color change can be increased when observed at different viewing angles.

  On the other hand, the embossed layers 12, 42, 52, and 62 are layers having fine irregularities on the surface that enable display of optically variable images by light interference and diffraction. For example, relief using light interference. It is a layer that has fine irregularities on its surface that have a diffraction structure pattern related to a type hologram or a diffraction grating, and the pattern changes depending on the difference in viewing angle.

  Relief-type holograms (diffraction gratings) are obtained, for example, by producing a relief-type master plate consisting of fine concavo-convex patterns by an optical imaging method, and then obtaining a press plate by copying the pattern from the master plate by electroplating. The press plate is obtained by pressing against a layer made of polycarbonate resin or the like and shaping. When forming relief holograms on the embossed layers 12, 42, 52, 62, such a method, that is, a method of forming a hologram by heating the press plate and pressing it against a thin film made of the material for forming the embossed layer is employed. . Therefore, the embossed layer 12 is made of a material that has good moldability by heat, hardly causes press unevenness, and can obtain a bright reproduced image.

Examples of the constituent material for the embossed layers 12, 42, 52, and 62 include thermoplastic resins such as acrylic resins, epoxy resins, cellulose resins, and vinyl resins, acrylic polyols and polyesters having reactive hydroxyl groups, and the like. Addition of polyisocyanate as a cross-linking agent to polyols, cross-linked urethane resins, thermosetting resins such as melamine resins and phenolic resins, and ultraviolet or electron beam curable resins such as epoxy (meth) acryl and urethane (meth) acrylates These can be used alone or in combination. In addition, resins other than those described above can be used as appropriate as long as they can form minute irregularities on the surface that can display an optically variable image by light interference or diffraction.

  The light reflecting layers 53 and 63 and the patterned light reflecting layers 13, 23, and 43 are provided to further enhance the optical effects of the embossed layers 12, 42, 52, and 62 described above. Examples of materials used for the light reflecting layers 53 and 63 and the patterned light reflecting layers 13, 23, and 43 include metal materials such as Al, Sn, Cr, Ni, Cu, and Au having high optical reflectivity. Can be mentioned. The film thickness varies depending on the reflectance of the constituent materials and the use, but may be about 1 to 100 nm. Alternatively, a paste containing a metal as described above may be used by screen printing or gravure printing.

  As shown in FIGS. 1, 2, and 4, when the patterned light reflecting layers 13, 23, and 43 are provided, for example, a thin film made of a material for forming a light reflecting layer is partially formed in a pattern such as a desired character or pattern. It may be formed automatically. Providing such pattern-like light reflecting layers 13, 23, 43 can improve the design and complicate processing, and can provide a higher forgery prevention effect.

  As a method of forming the patterned light reflecting layers 13, 23, 43, after forming a thin film made of a soluble resin in a pattern, a metal thin film is provided so as to cover the portion, and then the soluble resin and its A method of cleaning and removing a portion of the metal thin film, a method of etching a metal thin film with an acid or alkali after printing a pattern on the metal thin film using an acid or alkali resistant resin, or by exposing to light Further, there may be mentioned a method of applying a resin material that dissolves or hardly dissolves, exposes light through a mask in a desired shape, and then removes unnecessary portions by washing or etching. The above is an example, and the formation method of the patterned light reflection layer is not limited to these, and any general technique for partially forming a light reflective thin film such as a metal thin film can be used as appropriate. .

  On the other hand, a birefringent material can be used as a material for forming the retardation layers 14, 21, 22, 44, 54, 64. A birefringent material is an optical material whose refractive index varies depending on the direction of the optical axis, and its speed differs when light passes through it. A phase difference is generated by the difference. The phase difference value can be determined by the refractive index and the film thickness.

  In order to align the optical axis direction in the retardation layers 14, 21, 22, 44, 54, and 64 in a certain direction, for example, a liquid crystal material is applied on the alignment film that has been subjected to the alignment treatment in the certain direction. That's fine. In the case of aligning in the biaxial direction, for example, a liquid crystal material may be applied on an alignment film in which the direction of alignment treatment is partially changed.

  The liquid crystal material used for forming the retardation layers 14, 21, 22, 44, 54, 64 obtained as described above is a photocurable liquid crystal monomer having acrylates at both ends of the mesogenic group, EB or UV. Examples thereof include a cured polymer liquid crystal, a polymer liquid crystal having a mesogenic group in the polymer main chain, and a liquid crystal polymer in which the molecular main chain itself is aligned. These liquid crystal materials can be applied to the alignment film and then heat-treated at a temperature slightly below the NI point to promote alignment.

  For the alignment treatment of the alignment film for aligning the liquid crystal material, for example, a photo alignment method or a rubbing alignment method can be used.

  The photo-alignment method is a method that induces rearrangement of molecules in the alignment film and anisotropic chemical reaction by irradiating the alignment film with light having anisotropy such as polarized light or non-polarized light from an oblique direction. More specifically, by utilizing the fact that liquid crystal molecules are oriented by imparting anisotropy to the alignment film, pattern exposure is performed with polarized light in an appropriate wavelength band or oblique non-polarized light. Done.

In addition, when dividing the polarization latent image portion and the polarization background portion into two sections and changing the orientation direction in each portion, the pattern exposure is performed by covering the portion whose orientation direction is to be changed with a photomask, and further the photomask In order to process the unexposed portion covered with the above, the direction may be changed and pattern exposure may be performed on the portion. Alternatively, after the entire surface is once exposed to pattern, it may be partially covered with a photomask and changed in direction to be exposed again.
Examples of the photo-alignment mechanism include photoisomerization of azobenzene derivatives, photodimerization and crosslinking of derivatives such as cinnamic acid ester, coumarin, chalcone and benzophenone, and photolysis of polyimide and the like.

  On the other hand, the rubbing method is a method in which a polymer film is coated on a substrate and the film formed is rubbed with a cloth to create an alignment film. The properties of the film surface change in the rubbed direction, and the liquid crystal in this direction. This utilizes the property that molecules are aligned and an alignment film can be obtained. Examples of the polymer solution used for forming the alignment film include those using polyimide, PVA, and the like.

  Also, when the optical axis is oriented in two axes, the part whose orientation direction is to be changed is covered with a mask, rubbed with a cloth, the mask is removed, this time the part rubbed is covered with a mask, and again Use a method of removing the mask after changing the direction and rubbing with a cloth, or a method of removing the mask after rubbing the entire surface with a cloth, partially covering with a mask, rubbing with a cloth after changing direction. That's fine.

  As a method for forming a thin film for forming these alignment films, a known thin film forming method such as a gravure coating method or a micro gravure coating method can be used.

  Further, the light absorption layers 15 and 45 and the patterned light absorption layers 55 and 65 are layers provided to further enhance the optical characteristics of the multilayer thin film layers 18, 48, 58 and 68. The multilayer thin film layers 18, 48, 58, and 68 are layers having a property of absorbing a specific wavelength and reflecting other wavelengths depending on the film thickness, and the absorption wavelength is changed to the light absorption layers 15 and 45 and the pattern shape. By absorbing the light absorption layers 55 and 65, only the reflection wavelength can be seen more clearly. The colors of the light absorption layers 15 and 45 and the patterned light absorption layers 55 and 65 are not particularly limited as long as they are colors that can absorb the wavelength of light absorbed by the multilayer thin film layers 18, 48, 58, and 68. In general, a dark color is used, but black is generally used.

  Furthermore, the polarizing layers 46 and 66 are, for example, an absorption type polarizer in which PVA is impregnated with iodine or a dichroic dye and stretched and oriented, or an absorption type polarized light in which the dichroic dye is oriented in the form of an orientation film. Or a reflective polarizer in which a λ / 4 retardation film is combined with a cholesteric liquid crystal, a reflective polarizer in which a birefringent multilayer film is laminated, a prism polarizer formed into a lenticular lens shape with a Brewster angle, a birefringent material Is a layer composed of a birefringent diffractive polarizer formed in a diffraction grating shape, a diffractive polarizer formed with deep grooves in the diffractive structure, and the like. In addition to these polarizers, a layer made of an element capable of separating or extracting a specific polarization component by reflected light or transmitted light may be used.

Moreover, the forgery prevention medium of this invention may be provided with the adhesion layer and the contact bonding layer in the one part. Adhesive layers 17, 47, 57, 67 provided on the anti-counterfeit medium as shown in the figure are absorption layers 15, 45 and patterned light absorption layers 55, 65 in contact therewith, and base materials 11, 41, 51,
61, multilayer thin film layers 18, 48, 58, 68, patterned light reflecting layers 13, 23, 43 and light reflecting layers 53, 63 or embossed layers 12, 42, 52, 62 should not be altered or affected It can be formed using a general adhesive material. For example, vinyl chloride-vinyl acetate copolymer, polyester-based polyamide, acrylic-based, butyl rubber-based, natural rubber-based, silicon-based, polyisobutyl-based adhesive alone or alkyl methacrylate, vinyl ester, acrylonitrile, styrene, vinyl monomer Such as coagulating components such as unsaturated carboxylic acids, hydroxy group-containing monomers, acrylonitrile, and other additives such as polymerization initiators, polymerization initiators, plasticizers, curing agents, curing accelerators, and antioxidants. What was added according to it can be used. For the formation of the adhesive layers 17, 47, 57, 67, a known gravure printing method, offset printing method, screen printing method or other printing method, bar coating method, gravure method, roll coating method or other coating method may be used. I can do it.

Examples of the present invention will be described below.
First, Lumirror 25T60 (made by Toray Industries, Inc.), which is a biaxially stretched polyester film, is used as a base material, and a multilayer thin film layer having a thickness of 400 nm made of three layers of ceramic material is provided on one surface side by vacuum deposition. It was. This multilayer thin film layer is formed by laminating a high refractive index layer (thickness 100 nm) / low refractive index layer (thickness 200 nm) / high refractive index layer (thickness 100 nm) in this order. TiO ₂ was used, and SiO ₂ was used as a constituent material of the low refractive index layer.

  Next, an emboss layer forming material was applied on the obtained multilayer thin film layer with a thickness of 0.8 μm by a gravure printing method. Subsequently, a nickel mold having a fine concavo-convex diffraction grating pattern is heated to 165 ° C. and pressed onto the thin film formed in the above step by a roll embossing method. A diffraction grating pattern was formed. Next, an evaporated thin film made of aluminum was formed on the diffraction grating pattern so as to have a thickness of 80 nm by a vacuum evaporation method. Then, on the deposited aluminum vapor-deposited thin film, sorbine A, a vinyl chloride / vinyl acetate modified resin manufactured by Nisshin Chemical Co., was converted into an ink and printed in a pattern by a direct gravure printing method. Etching was performed by immersing in an aqueous sodium hydroxide solution, and the unnecessary deposited thin film was partially removed to obtain a patterned light reflecting layer.

And the thin film was apply | coated by the micro gravure printing method using IA-01 (made by Dainippon Ink and Chemicals, Inc.) which is a photo-alignment agent so that a pattern-form light reflection layer may be covered. This photo-alignment agent is a material having a liquid crystal alignment force in the polarization direction when irradiated with 365 nm polarized light. After irradiating the entire surface of the thin film made of the photo-alignment agent with polarized ultraviolet rays at ² J / cm ² , a photomask is arranged in a direction with an angle difference of 90 ° with respect to the polarization direction of the entire surface irradiation. The pattern was irradiated with ² J / cm ² using polarized ultraviolet rays. Thereafter, UV curable liquid crystal UCL-008 manufactured by Dainippon Ink & Chemicals, Inc. was applied with a micro gravure and UV-cured in an oxygen atmosphere to obtain a retardation layer.

  Further, a light absorption layer having a thickness of 0.8 μm was provided on the other surface side of the base material by direct gravure printing using SS66 911 ink manufactured by Toyo Ink Manufacturing Co., Ltd. Furthermore, an adhesive layer having a thickness of 10 μm is provided by a direct gravure printing method using an adhesive (BPS5160) manufactured by Toyo Ink Manufacturing Co., Ltd., and a release paper is pasted thereon, and then cut into a predetermined size. An anti-counterfeit medium (anti-counterfeit seal) of the invention was obtained.

When the anti-counterfeit medium thus obtained was visually observed, it was confirmed that the color of the portion having the reflective layer changes when the pattern of the diffraction structure changes the viewing angle. Further, the portion without the reflective layer showed reflection characteristics with respect to a specific wavelength in the visible light range, and it was confirmed that the reflection color changed from red to green according to the change in the viewing angle. Further, when the obtained anti-counterfeit medium was observed using a polarizer as a verification member, a latent image was confirmed at a portion having a reflective layer as shown in FIG. Furthermore, when this anti-counterfeit medium was copied with a copying machine, the color of the obtained copy did not change due to a different viewing angle, and the latent image could be confirmed even when observed through a polarizer. Therefore, it was confirmed that it has a function of easily distinguishing the genuine product from the duplicate product.

  Since the anti-counterfeit medium of the present invention has an anti-copying function, an overt function, and a covert function, it has excellent security, and prevents forgery of securities, branded products, certificates, etc. It can be widely used for labels, transfer foils, anti-counterfeit papers, and the like.

11 41 51 61 ... substrate 12 42 52 62 ... embossed layer 13 23 43 ... patterned light reflecting layer 53 63 ... light reflecting layer 14 21 22 44 54 64 ... phase difference layer 15 45... Light absorbing layer 55 65... Patterned light absorbing layer 46 66... Polarizing layer 17 47 57 67... Adhesive layer 18 48 58 68.

Claims (13)

  At least a patterned light reflecting layer is provided on the multilayer thin film layer that causes a color change in reflected light corresponding to a viewing angle under visible light irradiation, and further covers a part or the entire surface of the patterned light reflecting layer. A forgery-preventing medium comprising a retardation layer as described above.   On the surface of the multilayer thin film layer where the reflected light undergoes a color change corresponding to the viewing angle under visible light irradiation, the surface has at least minute irregularities that enable the display of optically variable images by light interference and diffraction. An anti-counterfeit medium, wherein an emboss layer and a patterned light reflecting layer are sequentially provided, and a retardation layer is provided so as to cover a part or the whole of the patterned light reflecting layer.   On the surface of the multilayer thin film layer that causes a color change in the reflected light corresponding to the viewing angle under irradiation of visible light, on the surface with at least minute irregularities that enable the display of optically variable images by light interference and diffraction An anti-counterfeit medium comprising an embossed layer, a patterned light reflecting layer, and a polarizing layer, and a retardation layer so as to cover a part or the entire surface of the patterned light reflecting layer. .   The forgery prevention medium according to any one of claims 1 to 3, wherein the multilayer thin film layer is provided on one surface side of the substrate.   The anti-counterfeit medium according to claim 4, wherein a light absorption layer is further provided on the other surface side of the base material.   An anti-counterfeit medium characterized in that at least a patterned light absorption layer and a reflective layer are sequentially provided on a multilayer thin film layer that causes a color change in reflected light corresponding to a viewing angle under irradiation of visible light. .   On the surface of the multilayer thin film layer where the reflected light undergoes a color change corresponding to the viewing angle under visible light irradiation, the surface has at least minute irregularities that enable the display of optically variable images by light interference and diffraction. An anti-counterfeit medium comprising an embossed layer, a patterned light absorbing layer, and a reflective layer sequentially provided.   The forgery prevention medium according to claim 6 or 7, wherein the multilayer thin film layer is provided on one surface side of the base material.   9. The medium for preventing forgery according to claim 8, wherein a retardation layer is provided on a part or the entire surface of the other surface of the base material.   The counterfeit prevention according to claim 8 or 9, wherein a polarizing layer is provided on the other surface side of the base material, and a retardation layer is sequentially provided on a part or the whole surface of the polarizing layer. Medium.   The forgery prevention medium according to claim 1, wherein the optical axis of the retardation layer is oriented in at least two axial directions.   The medium for preventing forgery according to any one of claims 1 to 11, further comprising an adhesive layer or an adhesive layer provided on one surface side. 2. A notch and / or a perforation is further provided in a part.
2. A medium for preventing forgery according to 2.