JP2012159771A - Forgery prevention medium and production method of the same, and method for determining authenticity of forgery prevention medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of a forgery prevention medium and a production method of the medium which makes it difficult to imitate a forgery prevention medium having the same visual effects as an authentic product and makes it difficult to determine an imitation level or target details of imitation, considering that the principal of a polarized latent image and its visual effects are well-known and the image is easily imitated or forged.SOLUTION: The forgery prevention medium 1 includes a reflection layer 12 formed on a substrate 11, and an intermediate layer 13 thereon, which is laid in a pattern of mountain range having the same height, the same inclination of slopes and ridgelines parallel to one another at the same pitch. A predetermined polarized latent image pattern is formed on slopes of one side in the mountain range-like intermediate layer 13, and a polarized latent image pattern different from the first pattern is formed on slopes in the other side. These polarized latent image patterns are formed of liquid crystal retardation layers having different retardation values from each other.

Description

  The present invention relates to a structure of a forgery prevention medium that makes a latent image such as a hidden character or a hidden pattern manifest by using a polarizing filter, a manufacturing method thereof, and an authenticity determination method for determining authenticity.

  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 simple flat plate polarizing plate is superimposed on a medium to cause a latent image to appear, and authenticity determination is performed based on whether the latent image is visible or not (see Patent Document 1).

JP 2008-183832 A

However, the principle and visual effect of a polarized latent image are already widely known, and imitation and counterfeiting are easy. Therefore, the anti-counterfeit effect cannot be expected with the polarization latent image technology that simply follows the conventional method.
Therefore, the present invention provides a structure of an anti-counterfeit medium that is difficult in the first place to imitate an anti-counterfeit medium that exhibits the same visual effect as a genuine product, and it is difficult to determine what to imitate and how to manufacture the medium. Was an issue.

  As a means for achieving the above object, the invention according to claim 1 is characterized in that, on the reflective layer formed on the substrate, the intermediate layer has the same height, the slope has the same slope, and the ridge line has It is laid in a mountain range so as to be parallel and at the same pitch, and has a predetermined polarization latent image pattern on the slope on one side of the mountain range intermediate layer, and also has a polarization latent image different from the above pattern on the slope on the other side. An anti-counterfeit medium comprising an image pattern, wherein the polarization latent image pattern is composed of liquid crystal layers having different retardation values.

  The invention according to claim 2 is the anti-counterfeit medium according to claim 1, wherein an adhesive layer is provided on the back surface of the base material.

  The invention according to claim 3 is directed to the anti-counterfeit medium according to whether the anti-counterfeit medium is observed from a plurality of directions through a polarizing plate, and a plurality of predetermined latent images appear. This is a method for determining the authenticity of an anti-counterfeit medium characterized by determining the authenticity of the medium.

The invention described in claim 4 includes a step of laminating a reflective layer, an intermediate layer, and an orientation control layer in this order on a substrate, a step of performing an orientation treatment on the orientation control layer so that liquid crystals are oriented, and orientation control. A step of applying a liquid crystal layer as a retardation layer on the layer, and a step of thermally embossing a laminated portion of the intermediate layer, the alignment control layer, and the retardation layer with an emboss plate having a predetermined surface shape. This is a method for manufacturing a forgery prevention medium.

  In the anti-counterfeit medium according to the present invention, since the surface is formed in a mountain range, the surface entering the field of view changes abruptly depending on the viewing angle, and a different polarization latent image pattern for each surface can be seen through the polarizing plate. It has become. In this case, the polarization latent image pattern does not change substantially unless it is observed from a considerable distance from the front direction, so even if you try to imitate it, you will not notice that there are multiple latent images (three front and left and right) hidden. There is an effect.

  In order to exert the above effect, it is necessary to form a surface in a mountain range and to lay a predetermined different polarization latent image pattern on both sides of the ridgeline. The surface of the embossed plate is formed on the polarization latent image pattern formed in advance. There is an effect that imitation is very difficult because it is necessary to highly align and press the unevenness.

  Further, since the polarization latent image pattern is colored, there is an effect that it is easy to distinguish the pattern and easily recognize forgery.

  Furthermore, what has an adhesion layer in the back surface of a base material has the effect that it can be easily stuck and used for a base material for pasting, such as paper and a film.

It is a top view which shows roughly the structure of the forgery prevention medium which concerns on this invention. It is sectional drawing along the AA line of the forgery prevention medium shown in FIG. FIG. 1 is a plan view showing the alignment direction of the alignment film of the anti-counterfeit medium. FIG. 2 is a schematic diagram schematically showing a method for providing a mountain range structure to an intermediate layer and a retardation layer of the forgery prevention medium shown in FIG. 1. It is a schematic diagram which shows an example of the latent image pattern which appears when it observes from a front direction through a polarizing plate using the forgery prevention medium of a structure of FIG. FIG. 6 is a schematic diagram showing an example of a latent image pattern that appears when the polarizing plate is rotated 45 degrees from the case of FIG. 5. It is a schematic diagram which shows an example of the latent image pattern which appears when it observes from the left side through a polarizing plate using the forgery prevention medium of a structure of FIG. FIG. 8 is a schematic diagram showing an example of a latent image pattern that appears when the polarizing plate is rotated 45 degrees from the case of FIG. 7. It is a schematic diagram which shows an example of the latent image pattern which appears when it observes from the right side through a polarizing plate using the forgery prevention medium of a structure of FIG. FIG. 10 is a schematic diagram showing an example of a latent image pattern that appears when the polarizing plate is rotated 45 degrees from the case of FIG. 9.

  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.

  FIG. 1 is a plan view schematically showing a forgery prevention medium according to the present invention. FIG. 2 is a cross-sectional view taken along line AA of the forgery prevention medium shown in FIG. 1 and 2, the X direction is a direction parallel to one side of the main surface of the anti-counterfeit medium 1, the Y direction is a direction perpendicular to the one side of the main surface, and the Z direction is the X direction. And a direction perpendicular to the Y direction.

  The anti-counterfeit medium 1 includes a base material 11, a reflective layer 12, an intermediate layer 13, and a retardation layer 14 as described in the cross-sectional view of FIG. The front surface of the anti-counterfeit medium 1 is the surface on the phase difference layer 14 side when viewed from the base material 11. It is also possible to place a protective layer on the retardation layer 14 so as to cover the retardation layer.

  On the front surface of the anti-counterfeit medium, an uneven portion having a cross-sectional shape of an isosceles triangle is formed so as to extend in a stripe shape. The mountain-shaped intermediate layer 13 is laid such that the height is the same, the slope is the same, the ridges are parallel, and have the same pitch. On the right slope of the mountain range, including the apex, a polarized latent image pattern with a sense of unity is formed only on the right slope, and on the left slope, a meaningful polarized latent image pattern is formed only on the left slope. Yes. In the front direction, the left and right slopes enter the field of view, but when the viewing angle is tilted left and right from the front direction, only one side of the slope enters the field of view at a certain angle.

(Base material)
The substrate 11 is a film or sheet made of a resin such as a polyethylene terephthalate (hereinafter referred to as “PET”) film. 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 substrate 11 can be omitted.

(Reflective layer)
The reflective layer 12 generally covers the entire front surface of the substrate 11, but may cover only a part of the front surface of the substrate 11. The reflective layer 12 may at least partially cover the back surface of the substrate 11. In this case, the base material 11 needs to be light-transmitting at at least a part of the position corresponding to the reflective layer 12, but typically, the base material 11 is at least one of the positions corresponding to the reflective layer 12. What is necessary is just to use a transparent part.

  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 layer may be provided 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, according to the present invention, a transfer foil having an ink layer having a light reflecting effect provided on the entire surface or in a pattern by a printing method or a transfer foil having a metal reflective layer is prepared. A reflective layer may be provided by transferring to the substrate 11 to be used, 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.

  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.

(Middle layer)
The intermediate layer 13 is a layer that supports the liquid crystal layer composing the retardation layer 14 and is laid under the retardation layer 14 in some cases in order to control alignment. Moreover, it is also a layer which substantially bears the mountain range structure so that the coated retardation layer 14 exhibits a predetermined mountain range structure.

  As a liquid crystal alignment control method, there is a method of forming an alignment film. As a method for imparting orientation to the alignment film, a known technique can be used, for example, a method of performing an alignment treatment by rubbing or vacuum oblique deposition, or a photo-alignment using a photoreaction by linearly polarized light or oblique non-polarized light irradiation. There is a method of orientation using a film. There is also a method in which fine grooves are formed on the surface of the intermediate layer 13 by embossing and the liquid crystal layer is aligned in the groove direction.

  FIG. 3 is an example showing the alignment direction of the alignment layer and its arrangement, and schematically shows a state having an effect of controlling the alignment of the liquid crystal in one direction 31 in which the stripe extends and another direction 32 different therefrom. Is.

(Retardation layer)
A liquid crystal material can be used for the retardation layer 14. Typically, the retardation layer 14 is a polymer birefringent layer obtained by curing a polymerizable liquid crystal material having fluidity with ultraviolet rays or heat. The liquid crystal layer is aligned according to the alignment direction of the alignment layer or the alignment control layer provided on the surface of the intermediate layer 13. Therefore, as shown in FIG. 1, the latent image display areas 101 and 102 and the latent image display areas 201 and 202 are oriented in different orientation directions. The pattern area 10 and the pattern area 20 correspond to the latent image display areas 101 and 102 and the latent image display areas 201 and 202, respectively.

Next, the outer shape and formation method of the mountain range structure of the intermediate layer 13 will be described.
FIG. 4 is a schematic diagram schematically showing a method for creating a mountain range structure in the intermediate layer 13. The embossed original plate 40 has a periodic mountain range structure (mountain-valley structure) with a pitch p, a height h, a width w, and a gradient θ in a cross-sectional view, and the top is an apex of an isosceles triangle and a narrow flat portion at the bottom. It has a shape. The mountain range structure is to prevent the other slope side from entering the field of view when viewed from one slope side. However, the outer shape of the mountain range may not have a flat portion, and the corner portion may have some roundness or change. Further, it is not necessary to have a triangular shape in a strict sense, and it is possible to obtain a similar visual effect even if it has a kamaboko shape, for example.

  The pitch p indicates the minimum cycle in which the pattern area is repeated. The width w indicates the half width of the pattern area. Moreover, the height h has shown the height difference of a mountain valley. Further, the gradient θ indicates an angle from a plane perpendicular to the Z direction of the mountain range structure. The pitch p, the height h, the width w, and the gradient θ need to be set in appropriate numerical ranges as visual recognition conditions when the polarization latent image is realized.

  If the intermediate layer 13 is, for example, a thermoplastic resin, the embossed original plate is pressed against the laminate of the intermediate layer 13 and the retardation layer 14 while applying heat, that is, the pitch p, A periodic mountain structure having a height h, a width w, and a gradient θ can be formed. Further, by using an ultraviolet curable resin or an orientation control material for the intermediate layer 13 and the retardation layer 14, the intermediate layer and the retardation layer are cured by irradiating ultraviolet rays while pressing the embossed original plate. It is also possible to form a mountain range structure by removing the original plate.

  At this time, if the orientation direction is different, the pattern region 10 and the pattern region 20 need to be aligned and embossed so as to be divided by the ridgeline of the mountain range structure.

(Authenticity judgment method)
Next, a mode in which a polarization latent image is observed using the anti-counterfeit medium 1 according to the present invention and an authenticity determination method for verifying that an article including the anti-counterfeit medium 1 is genuine will be described.

  FIG. 1 is a plan view schematically showing a forgery prevention medium 1. When visually observing without holding the polarizing plate 40, the latent image display areas indicated by dotted lines cannot be distinguished from each other, and all appear to be the same.

  FIG. 5 and FIG. 6 are plan views schematically showing an example of a polarization latent image when the polarizing plate 40 is held over the anti-counterfeit medium 1. The arrow indicates the optical axis direction of the polarizing plate 10.

  In FIG. 5, in the latent image display areas 101 and 201 in FIG. 1, since the optical axis direction of the polarizing plate and the optical axis direction of the retardation layer are parallel, the polarized light passing through the polarizing plate 10 can be transmitted. The latent image is displayed brightly. In the latent image display regions 102 and 202, since the direction of the optical axis of the polarizing plate and the direction of the optical axis of the retardation layer intersect at 45 °, the polarization via the polarizing plate 50 is rotated by 90 ° by the retardation layer. As a result, the light is shielded and displayed dark. At this time, the latent images in both the regions 10 and 20 can be observed.

  Next, FIG. 6 is a plan view showing a case where the anti-counterfeit medium 1 is observed when the polarizing plate is inclined by 45 ° from FIG. These are also based on the same principle as described above, and the display units 102 and 202 are dark, and the display units 102 and 202 display a latent image brightly in each region. Also here, both pattern areas 10 and 20 provided alternately are observed.

  FIG. 7 is a perspective view showing an example of a polarization latent image that appears when the polarizing plate 50 is held over the anti-counterfeit medium 1 and observed obliquely. As shown in FIG. 7, when the observation direction is tilted by an angle θ from the Z direction in a plane perpendicular to the X direction in the state shown in FIG. 5, only the pattern region 10 is observed. In these cases, the latent image display area 102 is dark and the latent image display area 101 is brightly displayed on the same principle as described above. For this reason, the polarization latent image is observed as one unified frame-like pattern, and the assumed effect is obtained.

  Next, FIG. 8 is a perspective view showing a manifest image when the anti-counterfeit medium 1 is observed when the polarizing plate is tilted 45 ° from FIG. In these cases, only the pattern region 10 is observed based on the same principle as described above. In addition, the latent image display area 101 is dark, the latent image display area 102 is bright, and an image in which the contrast is reversed from that in FIG. 7 is displayed based on the same principle as described above.

  FIG. 9 is a perspective view showing another example of a polarization latent image that appears when the polarizing plate 50 is held over the anti-counterfeit medium 1. As shown in FIG. 9, when the observation direction is tilted by an angle −θ from the Z direction in a plane perpendicular to the X direction in the state shown in FIG. 5, only the pattern region 20 is observed. In these cases, the latent image display area 202 is dark and the latent image display area 201 is brightly displayed on the same principle as described above. For this reason, the polarization latent image is observed as another meaningful circular pattern, and the assumed effect is obtained.

  Next, FIG. 10 is a perspective view showing a manifest image when the anti-counterfeit medium 1 is observed when the polarizing plate is tilted 45 ° from FIG. In these cases, only the pattern region 20 is observed based on the same principle as described above. In addition, the latent image display area 201 is dark, the latent image display area 202 is bright, and an image in which the contrast is reversed from that in FIG. 9 is displayed based on the same principle as described above.

As described above, the anti-counterfeit medium is normal if the attached anti-counterfeit medium is observed through the polarizing plate 50 at different angles, and an expected predetermined polarization latent image appears. It can be confirmed. If all the predetermined plural patterns (up to three on the front and left and right) do not appear, it is determined to be a counterfeit product. An authenticity determination can be made that an article provided with a regular anti-counterfeit medium is genuine. Of course, it is easy to adjust the appearance of the latent image pattern and the angle at which the latent image pattern appears by not forming either the left or right latent image pattern or making the mountain range asymmetric. Further, the latent image patterns appearing on the left and right are not necessarily different, and may be the same in some cases.

  An anti-counterfeit label can be formed on the back surface of the anti-counterfeit medium according to the present invention, for example, the back surface of the substrate 11 by applying an adhesive process with an adhesive or an adhesive. That is, a forgery prevention label may be formed using a forgery prevention medium.

  The anti-counterfeit medium according to the present invention can be applied to printed matter by various methods. For example, you may use the said forgery prevention label affixing on paper printed matter. 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. In this way, reuse of the label can be prevented. Of course, the anti-counterfeit medium according to the present invention can be used by being affixed to an article other than printed matter.

  When the anti-counterfeit medium is applied to a printed material, the anti-counterfeit medium may be scrubbed into paper in a form called a thread (also called 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 according to the present invention is not only used as a medium as a means for counterfeiting or duplication, but may be used as, for example, an electro-optical liquid crystal cell that performs optical and alignment functions.

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

  A reflective film 12 was obtained by providing a 50 nm-thick aluminum thin film layer on the entire surface using a vacuum deposition method using acryloprene HBS006 (manufactured by Mitsubishi Rayon Co., Ltd.), which is a PET film, as a base material 11.

  Next, a urethane resin was applied on the reflective layer 12 by microgravure at a coating thickness of 5 μm and a drying temperature of 110 ° C. to form an intermediate layer 13.

  Next, an alignment film ink solution was applied to the entire surface by a bar coater method (not shown). The composition of the applied alignment film ink is shown below.

Polyvinyl alcohol resin (trade name: PVA-117, Kuraray Co., Ltd.) 10% by weight
90% by weight of solvent (water)
This coating film was formed so that the dry film thickness was 2 μm.

  Next, this coating film was rubbed with a rubbing cloth (FINE PUFF YA-20-R manufactured by Yoshikawa Chemical Co., Ltd.) so that the orientation direction became the rubbing direction.

  Thereafter, a UV curable liquid crystal UCL-008 manufactured by Dainippon Ink & Chemicals, Inc. was coated as a retardation layer 14 with a microgravure and then cured by irradiation with non-polarized ultraviolet rays. Since the birefringence index of UCL-008 is 0.18, the film thickness is set to 1.52 μm so that the phase difference value is λ / 2 with respect to the light having a center wavelength of 550 nm of visible light. I made it.

  Next, an embossed original plate shown in the upper part of FIG. 4 was prepared.

Next, using the created embossed plate, the boundary between the region 10 and the region 20 is formed at the top of the mountain range (ridge line) at 220 ° C. and a pressure of 10 kgf / cm ² with respect to the lamination of the intermediate layer 13 and the retardation layer 14. Further, heat embossing was performed while aligning the emboss pitch, and the intermediate layer 13 and the retardation layer 14 were given a mountain range structure as shown in FIG.

  As a result, an anti-counterfeit medium 1 having different polarization latent images on both sides of the mountain range structure was obtained.

  Next, the authenticity of the forgery prevention medium 1 using a polarizing plate was determined.

  By observing the created anti-counterfeit medium through the polarizing plate, changing the viewing angle of the anti-counterfeit medium, multiple images change, and by changing the angle of the polarizing plate, the brightness of the polarization latent image is reversed. It was found that a predetermined latent image pattern was developed. If the predetermined latent image pattern appears by changing the viewing angle, the forgery prevention medium is authentic, and if it does not, it is a forgery product.

  The anti-counterfeit medium, the anti-counterfeit label, the printed matter, and the transfer foil according to 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 the anti-counterfeit medium enables the authenticity determination of the article as described above.

DESCRIPTION OF SYMBOLS 1 ... Anti-counterfeit medium 10, 20 ... Pattern area | region 11 ... Base material 12 ... Reflective layer 13 ... Intermediate | middle layer 14 ... Phase difference layer 31, 32 ... Orientation of alignment film Direction 40 ... Embossed original plate 50 ... Polarizing plate 101, 102, 201, 202 ... Latent image display area w ... Width p ... Pitch h ... Height θ ... Gradient

Claims (4)

  On the reflective layer formed on the substrate, the intermediate layer is laid in a mountain range so that the height is the same, the slope of the slope is the same, the ridges are parallel and have the same pitch, A liquid crystal layer having a predetermined polarization latent image pattern on one slope and a polarization latent image pattern different from the pattern on the other slope, the polarization latent image pattern having a different retardation value. An anti-counterfeit medium characterized by being composed of:   The forgery prevention medium according to claim 1, further comprising an adhesive layer on a back surface of the base material.   With respect to the anti-counterfeit medium, the anti-counterfeit medium is observed from a plurality of directions through a polarizing plate, and the authenticity of the anti-counterfeit medium is determined based on whether or not a plurality of predetermined latent images appear. A method for determining the authenticity of an anti-counterfeit medium. A step of laminating a reflective layer, an intermediate layer, and an orientation control layer in this order on a substrate;
Applying an alignment treatment to the alignment control layer so that the liquid crystal is aligned;
Applying a liquid crystal layer as a retardation layer on the orientation control layer;
And a step of thermally embossing a laminated portion of the intermediate layer, the orientation control layer, and the retardation layer with an emboss plate having a predetermined surface shape.