JP4550235B2 - Authenticator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an authenticity determination body that prevents counterfeiting of objects such as cards, gift certificates, cash vouchers, tickets, banknotes, passports, identification cards, securities, and public competition voting tickets.
[0002]
[Prior art]
Recently, forgery of gift certificates, securities, and the like has become a problem with the spread of high-definition and high-color reproducible color copying apparatuses.
In order to prevent such forgery, conventionally, a method has been proposed in which an authenticity determination object that is difficult to forge is attached to an authentic identification object, and this is visually or mechanically determined. Examples of such authenticity judgment bodies include a liquid crystal film (cholesteric liquid crystal) using a cholesteric liquid crystal whose reflected color changes depending on the viewing angle, and a nematic liquid crystal having optical anisotropy. There is a liquid crystal film that uses a liquid crystal film such as a liquid crystal film (Japanese Patent Laid-Open No. 8-43804). In particular, the method using a cholesteric liquid crystal is an excellent authenticity determination method because two characteristics of the cholesteric liquid crystal, that is, selective reflection and circular polarization selectivity, can be incorporated as information for determining authenticity.
[0003]
[Problems to be solved by the invention]
However, the above-described authenticity determination body using the cholesteric liquid crystal may cause light other than the light selectively reflected by the cholesteric liquid crystal to be reflected by the authentic identification target, and confirm the light selectively reflected by the cholesteric liquid crystal. It was difficult to do.
[0004]
The subject of this invention is providing the authenticity determination body which can authenticate authenticity reliably.
[0005]
[Means for Solving the Problems]
The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
In order to solve the above-mentioned problem, the invention of claim 1 reflects light (51) having a specific wavelength out of light (50) incident from one surface to exhibit a specific color, and other than the reflected light. The light (52) is transmitted, and when tilted, the light changes in color by reflecting light of different wavelengths, and is formed on the other surface of the color change layer (12) and the color change layer (12) capable of authentic identification, with the transmitted light absorbing layer that absorbs light (52) transmitted through the color change layer (12) and (13), the color changing layer (12) comprises a cholesteric liquid crystal, the color changing layer (12) A true / false determining body provided in part, formed by deforming the color change layer (12) as a whole in the thickness direction, and having an embossed portion (12a) for displaying an image .
[0006]
According to a second aspect of the present invention, in the authenticity determination body according to the first aspect, the transmitted light absorbing layer (13) is an adhesive layer that can be affixed to the authentic identification object (20). It is a fake verifier.
The invention according to claim 3 is the authenticity determination object according to claim 1, wherein the authenticity determination object is engraved in the paper base material of the authentic identification object. It is.
[0007]
According to a fourth aspect of the present invention, in the authenticity determination body according to any one of the first to third aspects, the transmitted light absorbing layer (13) transmits light transmitted through the color change layer (12). Among them, the authenticity determination body is characterized by reflecting light of a specific wavelength and absorbing light other than that light.
[0010]
According to a fifth aspect of the present invention, in the authenticity determination body according to any one of the first to fourth aspects, the color change layer (12) includes a hologram part (12b) that diffracts transmitted light. It is a true / false judgment object characterized by having.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
(First embodiment)
FIG. 1 is a view showing a first embodiment of the authenticity determination body according to the present invention, FIG. 1 (A) is a view showing a layer structure, and FIG. 1 (B) is a color change layer before and after emboss formation. It is an enlarged view shown.
The authenticity determination body 10 is of a so-called label type including a surface protective layer 11, a color change layer 12, an adhesive layer 13, and a release paper 14.
[0012]
The surface protective layer 11 is a layer that protects the surface of the authenticity determination body 10. Examples of the material of the surface protective layer 11 include acrylic resin, urethane resin, epoxy resin, silicon resin, EVA resin, polyamide resin, polyester resin, polystyrene resin, and cellulose resin. It is not limited to. The surface protective layer 11 may be appropriately selected according to the required physical properties such as light resistance, smoothness, hard coat property, and wear resistance required for the surface of the authenticity determination body 10 according to the application.
[0013]
The surface protective layer 11 is bonded to the color change layer 12. For this bonding, thermosetting resins (for example, phenol resins, furan resins, urea resins, melamine resins, polyester resins, polyurethane resins, epoxy resins and other resins), thermoplastic resins (for example, Polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride resin, polyvinyl butyral resin, poly (meth) acrylic resin, nitrocellulose, polyamide and other resins), rubber (for example, butadiene-acrylonitrile rubber, neoprene rubber and other rubber), glue, Among natural resins, casein, sodium silicate, dextrin, starch, gum arabic and the like, an adhesive mainly composed of one type or two or more types can be used. Such an adhesive may be any of a solution type, an emulsion type, a powder type, and a film type, and may be any of a room temperature solidification type, a solvent volatile solidification type, and a melt solidification type.
[0014]
The color change layer 12 has a cholesteric liquid crystal phase and exhibits different reflection colors depending on the viewing angle. The color change layer 12 has an embossed portion 12a, and the entire color change layer 12 is deformed in the embossed portion 12a (see FIG. 1B). The color change layer 12 displays an image by the embossed portion 12a. That is, the light incident on the embossed portion 12a is reflected in a different direction from the light incident on the flat portion other than the embossed portion 12a, so that an image can be visually observed with a difference in brightness.
In addition, the color change layer 12 may use any medium that exhibits optically selective reflectivity and circular polarization selectivity, such as a polymer film in which cholesteric liquid crystal alignment is fixed or a film in which cholesteric liquid crystal particles are dispersed in a carrier. Although it is possible, in particular, a polymer film in which liquid crystal alignment is fixed can be suitably used.
[0015]
Such a polymer film with a fixed liquid crystal alignment can be produced by cholesteric alignment of a low-molecular liquid crystal and then cross-linking the low-molecular liquid crystal by photoreaction or thermal reaction to fix the alignment state.
As another manufacturing method, a side chain type or main chain type thermotropic polymer liquid crystal is cholesterically aligned in a liquid crystal state, and then cooled to a temperature below the liquid crystal transition point to fix the alignment state. There is.
Furthermore, as another production method, there is a method of fixing the alignment state by gradually removing the solvent after cholesteric alignment of the side chain or main chain type lyotropic polymer liquid crystal in a solution.
[0016]
Examples of polymer liquid crystals that can be used in the production of these films include side-chain polymers such as polyacrylates, polymethacrylates, polysiloxanes, and polymalonates having a liquid crystal forming group in the side chain, and polyesters having a liquid crystal forming group in the main chain. Main chain polymers such as polyesteramide, polycarbonate, polyamide, and polyimide.
[0017]
The adhesive layer 13 is an adhesive layer having adhesiveness that can be applied to the authentic identification object 20, and includes, for example, vinyl acetate adhesive, acrylic adhesive, natural rubber adhesive, synthetic rubber adhesive, or silicone. It is formed by applying a rubber adhesive or the like. The adhesive layer 13 is colored black and absorbs light transmitted through the color change layer 12. Thus, since the adhesive layer 13 absorbs the transmitted light of the color change layer 12, it is possible to prevent excessive reflection due to the transmitted light and to easily visually check the image by the embossed portion 12a.
Note that the adhesive layer 13 may be colored with a color ink having a hue such as red, blue, or green and having low brightness (low reflectance) from the viewpoint of design. By doing so, the light having a specific wavelength out of the light transmitted through the color change layer 12 is reflected and the other light is absorbed, so that the appearance is very beautiful.
[0018]
The release paper 14 is a base material that protects the adhesive layer 13 before being attached to the authentic identification object 20. The release paper 14 is subjected to a release treatment with a silicone release agent or the like on its upper surface, that is, the surface on the adhesive layer 13 side. The thickness of the release paper 14 is not particularly limited, but is usually 20 to 200 μm, preferably about 40 to 100 μm.
[0019]
FIG. 2 is a diagram for explaining the operation of the color change layer and the adhesive layer of the first embodiment of the authenticity determination body according to the present invention.
The cholesteric liquid crystal fixed in the cholesteric alignment state in the color change layer 12 has a regular twist so that the alignment structure of the liquid crystal molecules draws a spiral in the film thickness direction. A cholesteric liquid crystal has two optical properties of selective reflection and circular polarization selectivity when the pitch P (the film thickness necessary for rotating liquid crystal molecules by 360 °) and the wavelength λ of incident light are substantially equal. (Reference: Basics of liquid crystal and display applications (Corona)).
[0020]
Here, selective reflectivity is a property of strongly reflecting light within a specific wavelength band of incident light and transmitting other light. Since the selective reflectivity is limitedly exhibited within a specific wavelength band, the reflected light becomes a chromatic color with high color purity by appropriately selecting the pitch P of the cholesteric liquid crystal. Λs the center wavelength of the band, if the bandwidth [Delta] [lambda], these are the pitch P of the optical medium (= λ / n _m) and the average refractive index _{n m (= √ ((n} e 2 + n o 2) / 2)) and the following equations (1) and (2). Here, [Delta] n is the difference between the extraordinary ray refractive index n _e and ordinary index n _o in the plane of the optical medium _{(Δn = n e -n o)} .
λs = n _m · P (1)
Δλ = Δn · P / n _m (2)
[0021]
The center wavelength λs and the wavelength bandwidth Δλ shown in the expressions (1) and (2) are the cases where the incident light to the cholesteric liquid crystal layer is perpendicularly incident (0 ° incidence, on-axis incidence). In the case of oblique incidence (off-axis incidence), since the pitch P apparently decreases, the center wavelength λs shifts to the short wavelength side, and the bandwidth Δλ decreases. This phenomenon is called blue shift because λs shifts to the short wavelength side, and the shift amount depends on the incident angle, but can be easily identified visually. For example, the reflected color of a cholesteric liquid crystal that displays red when viewed from the vertical (0 ° incident position) changes in order of orange, yellow, green, blue-green, and blue as the viewing angle increases. Looks like.
[0022]
The circularly polarized light selectivity is a property of reflecting only circularly polarized light in a specific rotation direction and transmitting circularly polarized light having the opposite rotation direction. Of the incident light, the circularly polarized light component in the same direction as the twist direction of the alignment structure of the cholesteric liquid crystal is reflected, and the rotational direction of the reflected light is also the same direction, while the circularly polarized light component rotating in the opposite direction is transmitted. . In the case of a cholesteric liquid crystal having a left twist structure, the left circularly polarized light is reflected, the reflected light remains as the left circularly polarized light, and the right circularly polarized light is transmitted.
[0023]
As shown in FIG. 2, when natural light 50 is incident on the color change layer 12 of the cholesteric liquid crystal having a left twisted structure, the left circularly polarized light 51 having the specific wavelength λ as described above is reflected and exhibits a specific reflected color. On the other hand, the other light 52 is transmitted and absorbed by the adhesive layer 13. For this reason, it is easy to confirm the reflected color of the color change layer 12.
[0024]
(how to use)
FIG. 3 is a diagram illustrating a usage state of the first embodiment of the authenticity determination object according to the present invention.
The authenticity determination body 10 is used by peeling the release paper 14 and affixing it to the authentication object 20 with the adhesive layer 13.
[0025]
According to this embodiment, since the adhesive layer 13 on the lower surface of the color change layer 12 is colored, it can be used regardless of the color, pattern, etc. of the authentic identification object 20.
Further, since the light transmitted through the color change layer 12 is absorbed by the adhesive layer 13, it is easy to confirm the color change of the color change layer 12.
Furthermore, since the adhesive layer 13 can be attached to the authentic identification object 20 and absorbs the transmitted light of the color change layer 12, the layer structure of the authenticity determination body 10 is simple and can be manufactured at low cost. .
Furthermore, when the adhesive layer 13 has a hue such as red, blue, or green and is colored with a color ink or the like having low brightness (low reflectance), only the light of a specific wavelength is reflected, and the color change layer Combined with 12 reflected lights, it is colorful. Also, light other than the specific wavelength light is absorbed, so it looks very clean.
[0026]
(Second Embodiment)
FIG. 4 is a diagram showing a second embodiment of the authenticity determination object according to the present invention.
In each embodiment described below, parts having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted as appropriate.
The color change layer 12 of this embodiment forms a hologram portion 12 b at the interface adjacent to the adhesive layer 13.
[0027]
(Production method)
The embossed hologram master-shaped irregularities are transferred to the color changing layer 12 of the cholesteric liquid crystal film by using a press device comprising a hot roll and a pressure roll to form the hologram portion 12b, and then the black adhesive An adhesive layer 13 having adhesiveness is formed by laminating an agent to produce a label type authenticity determination body 10.
[0028]
According to the present embodiment, the light transmitted through the color change layer 12 exhibits a hologram image of the light diffracted by the hologram portion 12b, and thus is excellent in design.
Moreover, since the hologram part 12b is difficult to manufacture, forgery is very difficult.
[0029]
(Third embodiment)
FIG. 5 is a diagram showing a third embodiment of the authenticity determination object according to the present invention.
The adhesive layer 13 of the authenticity determination body 10 of the present embodiment is a heat seal made of a hot melt material or the like, and is colored black or the like. Further, the authenticity determination body 10 is a so-called transfer foil type having a release layer 15 and a film layer 16 on the upper surface of the protective layer 11.
At the time of use, the adhesive layer 13 is applied to the authentic identification object 20, hot pressure is applied from the film layer 16 side with a hot stamp to adhere to the authentic identification object 20, and the film layer 16 is peeled off by the release layer 15.
[0030]
According to the present embodiment, since the authenticity determination body 10 can be transferred and adhered to the authentic identification object 20, it is excellent in mass productivity.
[0031]
(Deformation)
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
For example, although the embossed part or the hologram part is provided in the above embodiment, the effect that the reflected color of the color change layer 12 can be easily confirmed can be obtained without any of them.
Further, the hologram portion 12b may be formed on a separate film or the like and attached to the color change layer 12 instead of forming the color change layer 12.
Furthermore, in the third embodiment, it is not necessary to provide a hologram part as in the first embodiment.
Furthermore, the same effect can be obtained by embedding the authenticity determination body 10 in a paper base material by a thread method and forming the authenticity identification object with the paper base material.
[0032]
【The invention's effect】
As described above in detail, according to the present invention, since the transmitted light absorbing layer that absorbs the light transmitted through the color change layer is provided, it is easy to confirm the color change of the color change layer.
[0033]
According to the present invention, since the transmitted light absorption layer is also used as an adhesive layer that can be affixed to an authentic identification object, it is inexpensive to manufacture.
[0034]
According to the present invention, the transmitted light absorption layer reflects only light having a specific wavelength out of the light transmitted through the color change layer and absorbs light other than the light, and thus exhibits a bright color.
[0035]
According to the present invention, since the color change layer is a cholesteric liquid crystal, the color is beautiful and the design is excellent.
[0036]
According to the present invention, the color change layer has an embossed portion and displays an image, and thus is excellent in design.
[0037]
According to the present invention, the color change layer has a hologram part that diffracts the transmitted light, and is difficult to forge.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of a true / false determination object according to the present invention.
FIG. 2 is a diagram illustrating the operation of the color change layer and the adhesive layer of the first embodiment of the authenticity determination body according to the present invention.
FIG. 3 is a diagram illustrating a usage state of the first embodiment of the authenticity determination object according to the present invention.
FIG. 4 is a diagram showing a second embodiment of the authenticity determination body according to the present invention.
FIG. 5 is a diagram showing a third embodiment of the authenticity determination body according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Authenticity determination body 11 Surface protective layer 12 Color change layer 13 Adhesive layer 14 Release paper 15 Release layer 16 Film layer 20 Authenticity identification object

Claims (5)

Of the light incident from one surface, it reflects a specific wavelength and exhibits a specific color. Light other than the reflected light is transmitted, and when tilted, it reflects a different wavelength and changes its color. An identifiable color change layer;
A transmitted light absorbing layer that is formed on the other surface of the color change layer and absorbs light transmitted through the color change layer ;
The color change layer includes
Including cholesteric liquid crystal,
Provided in part of the color change layer, formed by deforming the color change layer entirely in the thickness direction, and having an embossed portion for displaying an image
A true / false verifier characterized by that. In the authenticity determination body according to claim 1,
The authenticity determination body, wherein the transmitted light absorption layer is an adhesive layer that can be attached to an authentic identification object. In the authenticity determination body according to claim 1,
The authenticity determination object is engraved in the paper base material of the authentic identification object.
A true / false verifier characterized by that. In the authenticity determination body according to any one of claims 1 to 3 ,
The transmitted light absorbing layer reflects a specific wavelength light out of the light transmitted through the color change layer and absorbs light other than the light. In the authenticity determination body according to any one of claims 1 to 4 ,
The authenticity determination body, wherein the color change layer has a hologram portion that diffracts transmitted light.

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