JP5696506B2 - Anti-counterfeit medium, authenticity determination method thereof, and manufacturing method of anti-counterfeit medium - Google Patents

Description

  The present invention relates to a structure of an anti-counterfeit medium that makes a latent image such as a hidden character or a hidden pattern appear by using a polarizing filter and an authenticity determination method for determining the authenticity of an anti-counterfeit medium.

  Conventionally, securities and authentication media such as banknotes, gift certificates, and passports have been made by pasting some medium that is difficult to forge (hereinafter referred to as an anti-counterfeit medium) as an anti-counterfeiting measure. There, the authenticity of the authentication medium is determined by the presence / absence of the anti-counterfeit medium or the authenticity determination of the anti-counterfeit medium itself by visual inspection or using a verifier.

  However, an anti-counterfeit medium that can determine authenticity by simple visual inspection is easily forged. Therefore, in recent years, a technique for forming a latent image that can be seen only with polarized light, which is more difficult to forge, in advance in a medium and revealing the latent image in combination with a polarizing plate has been disclosed as a forgery prevention technique. In this method, a monotone latent image appears by overlaying a simple flat polarizing plate on a medium, and authenticity determination is performed based on whether or not the latent image is visible (see Patent Document 1).

  The above prior invention patents are shown below.

JP 2008-183832 A

The anti-counterfeit medium using the above polarized latent image has a problem that since it is monotone, it has a weak power to appeal to the eye during verification, and cannot be distinguished from counterfeit at a glance. Moreover, even if it is difficult, it does not necessarily mean that it cannot be imitated or counterfeited.
Therefore, the present invention provides an anti-counterfeit medium that is a forgery-preventing medium using a polarization latent image, but is more difficult to forge and is visually easy to determine whether it is a forged medium. It was aimed.

As means for solving the above-mentioned problem, the invention according to claim 1 has a reflection layer on a substrate , a step having different depths for controlling the film thickness of liquid crystal in one plane, Using an embossed original plate on which no groove for alignment control is formed on the surface, an embossed surface after alignment is formed with a concavo-convex surface, an alignment controller for aligning liquid crystal, and the concavo-convex Thus, the forgery prevention medium is characterized in that a liquid crystal layer and a protective layer having different thicknesses and having a portion oriented in a predetermined direction by the effect of the orientation control unit are laminated in this order.

  The invention according to claim 2 is the anti-counterfeit medium according to claim 1, wherein the orientation control unit has a plurality of orientation directions.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the alignment controller is an alignment film formed on the surface of the formation layer with a material different from the formation layer. This is a medium for preventing forgery.

The invention according to claim 4 is the anti-counterfeit medium according to any one of claims 1 to 3 , wherein an adhesive layer is provided on the back surface of the base material. .

  The anti-counterfeit medium according to the present invention has a special visual effect that the polarization latent image that is seen when the polarizing plates are superimposed is colored in multiple colors, and different colored images can be observed when the polarizing plate is rotated. ing. Since the visualized colored image has a stronger appeal for vision than mono-color display and can be easily discriminated, it has the effect of exhibiting high forgery discrimination power.

  In addition, in order to color the polarization latent image, it is necessary to have advanced processing technology that secures multiple narrow spaces to accommodate the liquid crystal and imparts orientation to the wall surface, imitating such an environment surrounding the liquid crystal. Thus, it is extremely difficult to achieve the same visual effect as the genuine product compared to imitating the monotone type.

  In addition, the forgery prevention medium having a configuration having an adhesive layer on the back surface can be easily attached to a medium to be pasted such as paper.

  Further, if the macroscopic unevenness for changing the thickness of the liquid crystal and the fine groove for controlling the alignment of the liquid crystal are formed at the same time, the process can be streamlined and the anti-counterfeit medium having the above characteristics can be manufactured at a low cost. .

1 is a plan view schematically showing a forgery prevention medium according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of the forgery prevention medium illustrated in FIG. 1. It is a schematic diagram which shows schematically the preparation methods of the formation layer of the forgery prevention medium shown in FIG. It is a schematic diagram which shows schematically the formation layer obtained by FIG. (A), (B) It is a schematic diagram which shows various embodiment in the case of observing through a polarizing plate using the forgery prevention medium of a structure of FIG. It is a top view which shows roughly the forgery prevention medium which concerns on 2nd embodiment of this invention. FIG. 7 is a cross-sectional view taken along line BB of the forgery prevention medium illustrated in FIG. 6. FIG. 7 is a schematic diagram schematically showing a forgery prevention medium forming layer and an orientation control layer shown in FIG. 6. It is a schematic diagram which shows roughly the preparation methods of the formation layer of the forgery prevention medium shown in FIG. It is a schematic diagram which shows schematically the formation layer obtained by FIG. (A), (B) It is a schematic diagram which shows various embodiment in the case of observing through a polarizing plate using the forgery prevention medium of a structure of FIG. It is sectional drawing which shows an example of the layer structure of the transfer foil of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same referential mark is attached | subjected to the component which exhibits the same or similar function through all the drawings, and the overlapping description is abbreviate | omitted.

(First configuration)
FIG. 1 is a plan view schematically showing a first configuration of a forgery prevention medium according to the present invention.
FIG. 2 is a cross-sectional view of the forgery prevention medium 10 shown in FIG.

  The forgery prevention medium 10 includes a base material 11, a reflective layer 12, a forming layer 13, a liquid crystal layer 14, and a protective layer 15. The front surface of the anti-counterfeit medium 10 is a surface on the protective layer 15 side when viewed from the base material 11.

(Base material)
The base material 11 is a film or sheet made of a resin such as polyethylene terephthalate, for example. The substrate 11 may or may not have light transmittance. Moreover, the base material 11 may have a single layer structure, and may have a multilayer structure. Furthermore, the substrate 11 may be subjected to processing such as antistatic processing, mat processing, embossing processing, or the like, as long as it does not affect the image recognition of the polarization latent image. The base material 11 can be omitted if the reflective layer 12 is self-supporting.

(Reflective layer)
The reflective layer 12 covers the entire front side of the substrate 11. The reflective layer 12 may cover only a part of the front surface of the substrate 11. Alternatively, the reflective layer 12 may at least partially cover the back surface of the substrate 11. In this case, the base material 11 is light transmissive at at least a part of the position corresponding to the reflective layer 12. In this case, typically, the substrate 11 is transparent at least at a part of the position corresponding to the reflective layer 12.

  The reflective layer 12 may have a light scattering property or may not have a light scattering property. The reflective layer 12 may have a single layer structure or a multilayer structure.

  As a method of providing the reflective layer, an ink having a light reflecting effect may be provided by a known printing method, or a metal may be provided as a reflective layer by a method such as vapor deposition or sputtering. Examples of the metal used for the reflective layer include metals such as Al, Sn, Cr, Ni, Cu, Au, Inconel, stainless steel, and duralumin. In addition, the present invention may be applied by preparing a transfer foil in which an ink layer having a light reflection effect is provided on the entire surface or in a pattern by a printing method, or preparing a transfer foil provided with a metal reflective layer. A reflective layer may be provided by transferring to the base material 11 used in the above, or a reflective layer may be provided by laminating a metal foil or a film having a metal layer.

  When patterning the metal reflective layer, after forming the metal reflective layer on the entire surface of the base material, it may be patterned by a known method such as etching, laser processing, washing sea light processing, etc. The converted metal reflection layer may be transferred or laminated. Further, a diffractive structure forming layer having a diffractive structure may be provided instead of the flat metal reflective layer. By forming the diffractive structure, the decorative effect and the forgery prevention effect are improved.

  In the present invention, an OVD layer can be provided on the reflective layer. Examples of the OVD layer include optical layers such as holograms and diffraction gratings. Holograms include a relief type that records light interference on a flat surface as a fine concavo-convex pattern, a volume type that records interference fringes in the volume direction, etc. Among them, a relief hologram is preferably used in terms of mass productivity and cost. it can.

(Formation layer)
The formation layer 13 is a layer for controlling the orientation of the liquid crystal layer and the film thickness of the liquid crystal layer, and FIG. 3 is a schematic diagram schematically showing a method for forming the formation layer. The embossed original plate 41 has film thickness control regions 2A, 2B, 2C, etc. in one plane. The film thickness control regions 2A, 2B, and 2C have different depths. Moreover, it has the groove | channel 16 for orientation control. The regions where the grooves 16 for alignment control are formed are referred to as an alignment control region 21, an alignment control region 22, and the like. The orientation control region 21 and the orientation control region 22 can have different directions of the formed grooves 16.

  The formation layer 13 is, for example, a thermoplastic resin layer, and is obtained by a method of pressing an original plate provided with a plurality of convex portions while applying heat, that is, a heat embossing method. Alternatively, the forming layer 13 is, for example, an ultraviolet curable resin, and is formed by a method in which the ultraviolet curable resin is cured by irradiating ultraviolet rays from the back side of the resin base material while pressing the original plate on the original layer, and then the original plate is removed. Is also possible.

  In addition, by using the original plate having the groove 16 for alignment control, the uneven state for controlling the thickness of the liquid crystal layer and the alignment control groove 16 are formed on the formation layer 13 by the above method. Can be simultaneously formed. Moreover, you may form a site | part without a groove | channel.

  FIG. 4 is a schematic diagram schematically showing the formation layer 13 in which the film thickness control regions 2A, 2B, and 2C and the alignment control regions 21 and 22 are formed. The film thickness control regions 2A, 2B, and 2C have different depths. The alignment control region 21 and the alignment control region 22 are different in the direction in which the liquid crystal is aligned.

  According to these methods, a plurality of regions having different depths and widths of unevenness for film thickness control are processed on one side of the formation layer 13 to have grooves 16 having different extension directions for orientation control. Can do.

  Here, a structure that can be employed in each of the orientation control regions 21 and 22 will be described in detail. For each of the orientation control regions 21 and 22, for example, a structure in which a plurality of grooves 16 are arranged in parallel at equal intervals in the width direction can be employed.

  These grooves 16 are preferably parallel to each other, but may not be parallel in a strict sense. However, the closer the grooves 16 are in parallel, the easier the liquid crystal is aligned and the easier it is to align the optical axes in that direction. The angle formed by these grooves is, for example, 5 ° or less, and typically 3 ° or less.

  In each of the orientation control regions 21 and 22, these grooves 16 may be arranged vertically and horizontally. The lengths of the grooves may be equal to each other or different from each other. Further, the distance between adjacent grooves in the length direction may be uniform or non-uniform. Furthermore, the distance between adjacent grooves in the width direction may be uniform or non-uniform. For example, in each of the orientation control regions 21 and 22, the grooves 16 having the same length may be arranged vertically and horizontally. Alternatively, grooves 16 having various lengths may be randomly arranged in each of the orientation control regions 21 and 22.

  The depth of the grooves for controlling the orientation is, for example, in the range of 0.05 μm to 0.5 μm. The length of the groove is, for example, 0.5 μm or more. At this time, the depth of the groove is preferably sufficiently shallower than the thickness of the liquid crystal layer. The pitch of the grooves is, for example, 0.1 μm or more, and typically 0.75 μm or more. In order to align the liquid crystal with a high degree of order, it is advantageous that the groove pitch is small. The film thickness of the liquid crystal is, for example, 10 μm or less, and typically 2 μm to 6 μm.

(Liquid crystal layer)
The liquid crystal layer 14 is formed by solidifying a liquid crystal material. Typically, the liquid crystal layer 14 is a polymer birefringent layer formed by curing a polymerizable liquid crystal material having fluidity with ultraviolet rays or heat.

  As shown in FIG. 2, the liquid crystal layer 14 includes a plurality of liquid crystal portions 141 and 142 having different alignment states and a plurality of liquid crystal portions 14A, 14B, and 14C having different liquid crystal thicknesses. The plurality of liquid crystal portions 141 and 142 having different alignment states correspond to the alignment control regions 21 and 22, respectively. A plurality of liquid crystal regions 14A, 14B, and 14C having different film thicknesses correspond to the film thickness control regions 2A, 2B, and 2C, respectively.

(Protective layer)
The protective layer 15 covers the front surface of the liquid crystal layer 14. The protective layer 15 is a light-transmitting layer having light transmittance, and is typically transparent, but may be colorless and transparent, may be colored and transparent, at least optically, etc. It needs to be anisotropic.

  The protective layer 15 serves as a protective layer that suppresses the deterioration of the image displayed by the anti-counterfeit medium 10 so that the liquid crystal layer 14 or the like is not easily damaged or photodegraded. The protective layer 15 may have a single layer structure or a multilayer structure.

  The protective layer 15 is made of resin, for example. Examples of the material of the protective layer 15 include thermoplastic resins such as acrylic resin, urethane resin, vinyl chloride resin-vinyl acetate copolymer resin, polyester resin, melamine resin, epoxy resin, polystyrene resin, and polyimide resin, and thermosetting resin. , Or UV or electron beam curable resins can be used alone or in combination. The protective layer 15 can be omitted.

(Second configuration)
Next, the second configuration of the present invention will be described.
FIG. 6 is a plan view schematically showing the forgery prevention medium according to the second configuration of the present invention.
7 is a cross-sectional view of the forgery prevention medium shown in FIG. 6 taken along line BB.

  The forgery prevention medium 30 has the same configuration as the forgery prevention medium 10 described with reference to FIGS. 1 to 4 except that the following configuration is adopted. That is, the anti-counterfeit medium 30 is different only in the method of treating the surface of the regions 21 and 22 for controlling the alignment of the liquid crystal 13 in FIG. 1, and these portions are hereinafter referred to as alignment control layers 31 and 32.

(Orientation control layer)
The alignment control layer is used to align the liquid crystal, and a known technique can be used as a method of forming the alignment control layer. For example, a method of performing alignment treatment by rubbing or vacuum oblique deposition, linear polarization, oblique A method of aligning using a photo-alignment film using a photoreaction by non-polarized light irradiation can be employed. In this case, a different material from the forming layer material composing the groove is present on the forming layer.

  FIG. 8 shows the alignment direction of the alignment control layer. The alignment control layers 31 and 32 have the effect of controlling the alignment of the liquid crystal in the direction in which the stripes extend. The orientation direction is approximately 45 degrees on the left and right in FIG.

  FIG. 9 is a schematic view schematically showing a method for forming a formation layer. The embossed original plate 42 has steps (irregularities) having depths 2A, 2B, and 2C for controlling the film thickness of the liquid crystal in one plane, but no alignment control groove is formed on the step surface. is there. In the lower part of FIG. 9, the reflective layer 12 and the formation layer 13 are laminated on the front side of the base material 11, and the orientation control layers 31 and 32 are further formed thereon. Using this embossed original plate 42, alignment is embossed.

  FIG. 10 is a schematic diagram schematically showing a formation layer having uneven portions having depths 2A, 2B, and 2C for controlling the film thickness, and orientation control layers 31 and 32. FIG. According to the above method, a plurality of regions having different depths and widths for controlling the film thickness of the liquid crystal 13 can be formed in one plane. Also, according to these methods, a plurality of predetermined liquid crystal alignment properties can be imparted to the region. It can also be set as the orientation control layer which does not have orientation control ability. In this case, the liquid crystal becomes a non-oriented optically isotropic layer at the site.

(First observation form)
Next, a mode of observing a polarization latent image using the anti-counterfeit medium 10 of the present invention and an authenticity determination method for verifying that an article including the anti-counterfeit medium 10 is genuine will be described.

  FIG. 1 is a plan view schematically showing a forgery prevention medium 10. When visually observing without holding the polarizing plate 50, the latent image display area indicated by a dotted line cannot be distinguished from other areas, and all the areas look the same.

  FIGS. 5A and 5B are examples showing a polarization latent image when the polarizing plate 50 is held over the anti-counterfeit medium 10 of the present invention. The arrow indicates the optical axis direction of the polarizing plate 10.

  In FIG. 5A, the display portions 101 and 102 can transmit polarized light through the polarizing plate 10 because the optical axis of the polarizing plate and the optical axis of the retardation layer made of liquid crystal are parallel. Different color latent images are displayed brightly. In addition, in the display portions 201 and 202, since the angle of the optical axis of the polarizing plate and the optical axis of the liquid crystal layer intersect at 45 °, the polarized light passing through the polarizing plate 50 is blocked by being rotated 90 ° by the retardation layer. Appears dark. In the display portion 301, no change occurs because there is no liquid crystal region.

  FIG. 5B is a plan view showing how the anti-counterfeit medium 10 is seen when the polarizing plate is rotated by 45 ° from the state of FIG. In these cases, the display units 101 and 102 are dark on the same principle as described above, and the display units 201 and 202 display the latent images of different colors brightly in the respective regions.

  In this way, the anti-counterfeit medium 10 is observed through the polarizing plate 50, and it is confirmed that the polarization latent image is a latent image pattern having a predetermined coloring state. It can be confirmed that If the medium is an anti-counterfeit medium showing the same polarization latent image, it is possible to determine whether the article provided with the medium is genuine.

(Second observation form)
The same effect as that of the anti-counterfeit medium 10 can be obtained in the anti-counterfeit medium 30 and an authenticity determination can be made that an article including the anti-counterfeit medium is a genuine product.

  Here, the reason why the display unit 101, the display unit 201, the display unit 102, and the display unit 202 look different colors will be described with reference to mathematical expressions.

  The retardation Re of the liquid crystal layer depends on the film thickness d of the liquid crystal layer and its birefringence Δn, as shown in the following equation (1).

Re = Δn × d (1)
Here, a _{Δn = n e -n o, n} e, n o are each extraordinary light refractive index for ordinary light.

A pair of linearly polarizing films face each other so that their transmission axes are parallel or orthogonal, and a liquid crystal layer is interposed between them so that the optical axis forms an angle θ with respect to one transmission axis of the linearly polarizing film. Let When one linearly polarizing film is illuminated with light having a wavelength λ from its normal direction, the intensity of light incident on the liquid crystal layer is I ₀ and the intensity of light passing through the other linearly polarizing film is I. I can be represented by the following equation (2).

I = I ₀ × sin ² (2θ) × sin ² (Re × π / λ) (2)
As is clear from the equation (2), the wavelength λ at which the intensity I of the transmitted light has the maximum value depends on the retardation Re. As shown in the equation (1), the retardation Re depends on the film thickness d of the liquid crystal layer and its birefringence Δn. That is, the wavelength λ at which the transmitted light intensity I is maximum depends on the film thickness d of the liquid crystal layer. Therefore, the spectrum of transmitted light has a different profile from the spectrum of incident light.

  Thus, when the liquid crystal layer is sandwiched between a pair of linearly polarizing films, transmitted light having a spectrum profile different from that of incident light can be obtained. Similarly, when a liquid crystal layer is sandwiched between a linearly polarizing film and a reflective layer, it is the same as sandwiching a liquid crystal layer between a pair of linearly polarizing films, and incident light is reflected light having a different spectral profile. Can be obtained. Accordingly, the display portions 101, 201, 102, and 202 look different colors because the thickness and the orientation direction are different.

  An information display layer may be provided on the substrate 11 or / or the reflective layer 12, the liquid crystal layer 14, and the protective layer 15. At this time, care should be taken not to hide the polarization latent image.

  The information display layer is a layer for holding information such as individual identification information by letters and numbers on a label, and a known method is appropriately used for the material and the forming method. For example, various ink printing methods such as gravure printing method and screen printing method, and metal thin film formation methods such as vacuum deposition method are possible.

  An anti-counterfeit label can be formed by subjecting the back surface of the anti-counterfeit medium of the present invention, for example, the back surface (back surface) of the base material 11 to adhesion processing with an adhesive or an adhesive. That is, an anti-counterfeit label may be formed using an anti-counterfeit medium.

  The anti-counterfeit medium of the present invention can be applied to printed matter by various methods. For example, the forgery prevention label may be a printed material affixed to a printed material using paper or the like.

  In this case, the base material 11 may be provided with cuts or perforations. Thereby, when it is going to peel off a label, the structure where the base material 11 is torn from a notch | incision is employable. If it is easy to tear, it will be difficult to paste and reuse. Of course, the anti-counterfeit medium of the present invention can also be used by being attached to an article other than printed matter.

  In the anti-counterfeit medium of the present invention, a transfer foil can be formed by including a support substrate and an adhesive layer that can be peeled. Moreover, you may use this transfer foil, attaching to articles | goods.

  In the case of a transfer foil, the reflective layer 12 needs to be placed on the liquid crystal layer 14 or the protective layer 15.

FIG. 12 is a cross-sectional view schematically showing an example of a transfer foil using the anti-counterfeit medium of the present invention.
In the transfer foil 60, a release layer 62, an anti-counterfeit medium, and an adhesive layer 63 are sequentially laminated on a base 61. As the anti-counterfeit medium, the anti-counterfeit medium shown in the first and second configurations can be used. The release layer 62 desirably does not absorb ultraviolet rays.

  The front surface of the forgery prevention medium faces the base material 61. The anti-counterfeit medium may not include the base material 11 described with reference to FIGS.

  When the anti-counterfeit medium is applied to the printed matter, the anti-counterfeit medium may be inserted into the paper in a form called a thread (also referred to as a strip, a filament, a thread, a safety band, or the like).

  When an adhesive is used in the anti-counterfeit label or printed matter, a general material can be used as the material of the adhesive.

  For example, an adhesive such as vinyl chloride-vinyl acetate copolymer, polyester polyamide, acrylic, butyl rubber, natural rubber, silicon, or polyisobutyl can be used alone. Or these pressure sensitive adhesives include coagulation components such as alkyl methacrylates, vinyl esters, acrylonitrile, styrene, vinyl monomers, modifying components such as unsaturated carboxylic acids, hydroxy group-containing monomers, acrylonitrile, polymerization initiators, plastics What added additives, such as an agent, a hardening | curing agent, a hardening accelerator, antioxidant, as needed can be used.

  As a method for forming the adhesive layer, a known gravure printing method, an offset printing method, a screen printing method or the like printing method or a bar coating method, a gravure method, a roll coating method or the like can be used.

  Furthermore, what formed the said adhesive in the separator previously may be prepared, a separator may be peeled off and bonded together to a forgery prevention medium.

  Further, in order to facilitate the handling of the anti-counterfeit medium subjected to the adhesive processing, a release paper or a release film subjected to a release treatment may be installed on the adhesive layer.

  The anti-counterfeit medium of the present invention is not only used as a medium as a means for counterfeiting or duplication, but may be used, for example, as an electro-optical liquid crystal cell that performs optical and alignment functions.

  Hereinafter, specific examples of the forgery prevention medium of the present invention will be described with reference to FIGS.

  A polyethylene terephthalate film subjected to a release treatment was prepared, and an aluminum thin film layer having a film thickness of 50 nm was provided on the entire surface as the reflective layer 12 using a vacuum deposition method.

  Next, the formation layer 13 was formed on the reflective layer 12 by applying a urethane resin by microgravure at a coating thickness of 8 μm and a drying temperature of 110 ° C.

Next, an alignment film ink solution was applied to the entire surface by a bar coater method. The composition of the applied alignment film ink is shown below.
・ Polyvinyl alcohol resin (trade name: PVA-117, Kuraray Co., Ltd.) 10% by weight
・ Solvent (water) 90% by weight
This coating film was formed so that the dry film thickness was 2 μm.

Next, using a rubbing cloth (FINE PUFF YA-20-R manufactured by Yoshikawa Chemical Co., Ltd.), the coating film was covered with one side and the other was rubbed twice. As a result, two alignment control regions having different alignment directions as shown in FIG. 8 were obtained.

  Next, an embossed original plate having a step (uneven portion) as schematically shown in the upper part of FIG. 9 was prepared. The depths of the uneven portions 2A, 2B, and 2C were 3 μm, 4 μm, and 5 μm, respectively.

Next, the embossed plate was used to thermally emboss the formed layer at 220 ° C. and a pressure of 10 kgf / cm ² , and an uneven region for controlling the thickness of the film was transferred and formed on the formed layer as shown in FIG.

  Thereafter, UV curable liquid crystal UCL-008 manufactured by Dainippon Ink & Chemicals, Inc. was coated on the forming layer 13 by microgravure and then cured by irradiating non-polarized ultraviolet rays. The liquid crystal layer 14 was formed so as to embed uneven regions having different depths of the formation layer 13. You may form so that the formation layer 13 may be coat | covered thinly.

  Next, an acrylic resin was formed as the protective layer 15 by microgravure at a coating thickness of 1 μm and a drying temperature of 100 ° C.

  Next, the anti-counterfeit medium 10 using the polarizing plate 50 was observed to check whether a desired image appeared.

  FIG. 5A is a plan view showing an example in which the created anti-counterfeit medium 10 is observed through the polarizing plate 50. In the display units 101 and 102, since the optical axis of the polarizing plate and the optical axis of the retardation layer are parallel, the polarized light passing through the polarizing plate 10 can be transmitted, and a latent image of a different color is displayed brightly in each region. The In addition, in the display portions 201 and 202, since the angle of the optical axis of the polarizing plate and the optical axis of the liquid crystal layer intersect at 45 °, the polarized light passing through the polarizing plate 50 is blocked by being rotated 90 ° by the retardation layer. Appears dark. In the region 301, no change occurs because there is no liquid crystal region.

  Next, FIG. 5B is a plan view showing an example of observing the forgery prevention medium 10 when the polarizing plate is rotated by 45 ° from FIG. In these cases, the display units 101 and 102 are dark on the same principle as described above, and the display units 201 and 202 display the latent images of different colors brightly in the respective areas.

  By changing the angle of the polarizing plate through the polarizing plate in this way, it is possible to determine whether or not the light and darkness of the polarization latent image is reversed. An anti-counterfeit medium in which a desired image does not appear is determined to be a counterfeit product.

  The anti-counterfeit medium, the anti-counterfeit label, the printed matter, and the transfer foil of the present invention can be used for the above-mentioned article as a counter measure against forgery in securities such as banknotes, gift certificates, passports, and various authentication media. Further, the authenticity determination method for an anti-counterfeit medium of the present invention makes it possible to determine the authenticity of an article as described above.

10, 30 ... Anti-counterfeit medium 11, 61 ... Base material 12 ... Reflective layer 13 ... Formation layer 14 ... Liquid crystal layers 14A, 14B, 14C ... Liquid crystal portions 141 with different film thicknesses , 142, 143, 144... Liquid crystal regions 15 having different orientations... Protective layer 16... Grooves 2 A, 2 B, 2 C... Film thickness control regions 21, 22. ..Alignment control regions 41, 42 ... Embossed original plate 50 ... Polarizing plate 62 ... Release layer 63 ... Adhesive layers 101, 102, 201, 202, 301 ... Display

Claims (4)

  Using an embossed original plate that has a reflective layer on the substrate, a step having different depths for controlling the film thickness of the liquid crystal in one plane, and no alignment control groove is formed on the surface of the step. The formation layer where the surface embossed on top of each other exhibits an uneven state, the alignment control unit for aligning the liquid crystal, the thickness varies by embedding the unevenness, and the portion oriented in the predetermined direction by the effect of the alignment control unit An anti-counterfeit medium characterized in that a liquid crystal layer and a protective layer are laminated in this order.   The forgery prevention medium according to claim 1, wherein the orientation control unit has a plurality of orientation directions.   The anti-counterfeit medium according to claim 1 or 2, wherein the orientation control unit is an orientation film formed on the surface of the formation layer with a material different from the formation layer. The forgery prevention medium according to any one of claims 1 to 3 , wherein an adhesive layer is provided on a back surface of the base material.