JP2014076583A - Forgery prevention medium, and forgery prevention sticker and forgery prevention article using the same - Google Patents

Abstract

There is provided a medium capable of developing a negative / positive inversion latent image using a polarizing plate and capable of individually forming a latent image using a relatively inexpensive and simple apparatus.
In a forgery prevention medium 20 in which a first retardation layer 102, a first reflection layer 103, a second retardation layer 104, and a second reflection layer 105 are laminated in this order, the first retardation layer 102 and the first retardation layer 102 are provided. The two retardation layer 104 was provided on the entire surface direction. The first retardation layer 102 and the second retardation layer 104 both have a retardation value of λ / 4, and the angle formed by the orientation axes of the first retardation layer 102 and the second retardation layer 104 is 45 degrees. is there.
[Selection] Figure 1

Description

  The present invention relates to an anti-counterfeit medium used for various articles, an anti-counterfeit sticker using the medium, and an anti-counterfeit article.

Anti-counterfeiting technology is used for various articles. For example, it is used for banknotes, bonds, gift certificates, cash vouchers such as checks, and securities. It is also used for various certificates such as credit cards, ID cards, official documents, and important documents.
In recent years, it has been applied to various products and their packaging materials to ensure that the products are authentic. Needless to say, if these articles are inspected and proper anti-counterfeiting measures are taken, they are judged as genuine articles, and if no anti-counterfeiting measures are taken or improper measures are not accepted. It is determined as an authentic article.

As one of anti-counterfeiting means, Patent Document 1 proposes a medium that develops a latent image that undergoes negative-positive inversion using a polarizing plate by photo-aligning liquid crystal. This is because a person who does not know how to develop a latent image cannot visually recognize the latent image, and therefore, even if the counterfeit product is created by imitating only the appearance, a non-authentic article can be easily identified.
In addition, as in Patent Document 2, there is also proposed a method of forming individual images using a hologram that is effective as a forgery prevention unit. If this method is used, personal authentication with high anti-counterfeiting effect can be easily performed by human eyes.

Japanese translation of PCT publication No. 2002-530687 JP 2011-230473 A

  In the case of the medium described in Patent Document 1, in order to produce this medium, it is necessary to perform photo-alignment by pattern exposure, coat and align the liquid crystal monomer, and then crosslink the liquid crystal with light. Therefore, it is necessary to go through a relatively complicated process after forming a latent image pattern by pattern exposure, and large-scale equipment such as a coater, an oven, and a light irradiation device is required. For this reason, when such a medium is mass-produced, the latent images have the same pattern. In other words, in order to individually create latent images with different patterns, it is difficult from the viewpoint of cost and equipment, and it is unavoidable that the latent images have the same pattern.

On the other hand, in the case of the medium described in Patent Document 2, although it is a visible anti-counterfeit effect called a hologram, it is possible to form individual images relatively easily using a thermal head or the like. By applying the method for producing a medium having an anti-counterfeit effect described in Patent Document 2, a retardation film such as a cross-linked liquid crystal film or a stretched polymer having the same performance is used for the medium described in Patent Document 2. Thus, if it can be formed individually, a medium with a higher anti-counterfeit effect can be created. However, since the stretched polymer is thick, it is impossible to form individual images with a thermal head or the like. Further, the liquid crystal film is a very thin film but is relatively strong as a film because it is cross-linked by light, and is not brittle enough to form an individual image with a thermal head.
An object of the present invention is to provide an anti-counterfeit medium capable of individually forming a latent image using a relatively inexpensive and simple device, an anti-counterfeit sticker and an anti-counterfeit article using the medium.

  One embodiment of the present invention includes a first retardation layer (for example, the first retardation layer 102 in FIG. 1), a first reflective layer (for example, the first reflective layer 103 in FIG. 1), and a second retardation layer. 1 (for example, the second retardation layer 104 in FIG. 1) and a second reflection layer (for example, the second reflection layer 105 in FIG. 1) are laminated in this order (for example, the forgery in FIG. 1). Prevention medium 20), wherein the first retardation layer and the second retardation layer are provided over the entire surface direction, and the retardation values of the first retardation layer and the second retardation layer are both λ. The anti-counterfeit medium is characterized in that the angle between the orientation axes of the first retardation layer and the second retardation layer is 45 degrees.

  Another aspect of the present invention includes a first retardation layer (for example, the first retardation layer 102 in FIG. 2), a first reflective layer (for example, the first reflective layer 103 in FIG. 2), and a second retardation. A layer (for example, the second retardation layer 104 in FIG. 2), a second reflective layer (for example, the second reflective layer 105 in FIG. 2), and a color change layer (for example, the cholesteric layer and the black absorbing layer 106 in FIG. 2). ) Are stacked in this order (for example, the anti-counterfeit medium 30 in FIG. 2), wherein the first retardation layer and the second retardation layer are provided over the entire surface direction, and The retardation values of the first retardation layer and the second retardation layer are both λ / 4, and the angle between the orientation axes of the first retardation layer and the second retardation layer is 45 degrees. It is a medium for preventing forgery.

  Another aspect of the present invention includes a first retardation layer (for example, the first retardation layer 102 in FIG. 10), a first reflective layer (for example, the first reflective layer 103 in FIG. 10), and a second retardation. A layer (for example, the second retardation layer 104 in FIG. 10), a second reflective layer (for example, the second reflective layer 105 in FIG. 10), and a third retardation layer (for example, the third retardation layer in FIG. 10). 301) is a counterfeit prevention medium (for example, the double-sided latent image forgery prevention medium 40 in FIG. 10) laminated in this order, and includes the first retardation layer, the second retardation layer, and the third retardation. The layers are respectively provided over the entire surface direction, and the retardation values of the first retardation layer, the second retardation layer, and the third retardation layer are each λ / 4, and the first retardation layer And the angle formed between the orientation axes of the second retardation layer and the second retardation layer and the third retardation layer. Angle of adaxial is 45 degrees, respectively, wherein the first retardation layer and the angle of mutual alignment axis of the third retardation layer is a medium for preventing forgery characterized in that it is a 0 degrees.

  Another aspect of the present invention includes a first retardation layer (for example, the first retardation layer 102 in FIG. 10), a first reflective layer (for example, the first reflective layer 103 in FIG. 10), and a second retardation. A layer (for example, the second retardation layer 104 in FIG. 10), a second reflective layer (for example, the second reflective layer 105 in FIG. 10), and a third retardation layer (for example, the third retardation layer in FIG. 10). 301) is a counterfeit prevention medium (for example, the double-sided latent image forgery prevention medium 40 in FIG. 10) laminated in this order, and includes the first retardation layer, the second retardation layer, and the third retardation. The layers are respectively provided over the entire surface direction, and the retardation values of the first retardation layer, the second retardation layer, and the third retardation layer are each λ / 4, and the first retardation layer And the angle formed between the orientation axes of the second retardation layer and the second retardation layer and the third retardation layer. Angle of adaxial is 45 degrees, respectively, the angle between one another of the orientation axis of the first retardation layer and the third retardation layer is the medium for preventing forgery, characterized in that it is 90 degrees.

The color change layer (for example, the cholesteric layer and the black absorption layer 106 in FIG. 2) may include a cholesteric liquid crystal.
The first reflective layer (for example, the first diffractive reflective layer 503 in FIG. 17) and the second reflective layer (for example, the second diffractive reflective layer 505 in FIG. 17) each have a diffractive structure, and the first reflective layer And the second reflective layer may be provided so that the positions of the diffractive structures of the reflective layers overlap each other.

Another aspect of the present invention is a forgery prevention sticker characterized in that an adhesive layer is provided on a surface opposite to the observation surface of the forgery prevention medium according to any one of the above aspects.
Another aspect of the present invention is an anti-counterfeit article comprising the anti-counterfeit medium according to any one of the above aspects.

  According to the present invention, it is possible to develop a latent image that undergoes negative-positive inversion using a polarizing plate, and it is possible to individually form latent images using a relatively inexpensive and simple apparatus.

It is sectional drawing which shows an example of the fundamental layer structure of the forgery prevention medium in this invention. It is sectional drawing which shows an example of the layer structure of the forgery prevention medium with a cholesteric. It is an example of the schematic diagram which showed the forgery prevention medium, the cross section of the polarizing plate in the state overlaid with this forgery prevention medium at 0 degree | times, and also the change of the light which passes these anti-counterfeit medium and a polarizing plate. It is an example of the schematic diagram which showed the forgery prevention medium, the cross section of the polarizing plate in the state piled up with this forgery prevention medium at 45 degree | times, and also the change of the light which passes these forgery prevention medium and a polarizing plate. FIG. 5 is a graph in which the intensity of reflected light from the observation lights A to F in FIGS. 3 and 4 is normalized individually. It is a top view which shows an example of the forgery prevention medium with a cholesteric. It is a top view which shows an example of the 2nd reflection layer pattern of a forgery prevention medium with a cholesteric. It is an example of a top view when a polarizing plate is overlapped at an angle of 45 degrees on a forgery prevention medium with cholesteric. It is an example of the top view at the time of laminating | stacking a polarizing plate on the anti-counterfeit medium with a cholesteric at an angle of 0 degree | times. It is sectional drawing which shows an example of a layer structure of the forgery prevention medium with a 3rd phase difference layer. It is an example of the 1st reflection layer pattern of a forgery prevention medium with a 3rd phase difference layer. It is an example of the 2nd reflection layer pattern of a forgery prevention medium with a 3rd phase difference layer. It is an example at the time of laminating | stacking a polarizing plate on the surface side which makes the 1st phase difference layer of an anti-counterfeit medium with a 3rd phase difference layer the outermost surface. This is an example in which a polarizing plate is overlaid on the surface opposite to the surface having the first retardation layer of the forgery prevention medium with the third retardation layer as the outermost surface. It is an example of the schematic diagram which showed the cross section at the time of superimposing a right circularly polarized light reflection cholesteric layer and a black reflective layer on the forgery prevention medium with a 3rd phase difference layer, and also the change of the light which passes this this forgery prevention medium. It is an example of the schematic diagram which showed the cross section at the time of superimposing a left circularly polarized light reflection cholesteric layer and a black reflective layer on the forgery prevention medium with a 3rd phase difference layer, and also the change of the light which passes this this forgery prevention medium. It is sectional drawing which shows an example of the forgery prevention medium which has a layer structure of the structure in which the 1st reflection layer and the 2nd reflection layer have a diffraction structure. It is a top view which shows an example of a 2nd diffraction reflection layer. It is a top view which shows an example of a 1st diffraction reflection layer. It is sectional drawing which shows an example of the transparent base material in which the double-sided latent image forgery prevention medium and the circularly polarized light reflector were provided.

Hereinafter, the present invention will be described in detail.
(Layer structure of anti-counterfeit medium 20)
FIG. 1 shows an example of the layer structure of the anti-counterfeit medium according to the present invention, and shows the minimum structure composed of the minimum necessary components.
The anti-counterfeit medium 20 includes a first retardation layer 102, a first reflection layer 103, a second retardation layer 104, and a second reflection layer 105 that are stacked in this order. The polarizing plate 10 is arranged on the first retardation layer 102 side of the forgery prevention medium 20 as a verification filter for confirming the effect of the forgery prevention medium 20.

(Configuration of the first retardation layer 102 and the second retardation layer 104)
The first retardation layer 102 and the second retardation layer 104 are uniform films having a retardation value of λ / 4, and λ is preferably designed by setting a visible light wavelength. It is preferable to set a value around the central 555 nm. The angle formed by the orientation axis directions of the first retardation layer 102 and the second retardation layer 104 is 45 degrees. The first retardation layer 102 and the second retardation layer 104 both cover the entire forgery prevention medium 20.

  As materials for the first retardation layer 102 and the second retardation layer 104, firstly, polymer resins such as cellophane, polycarbonate, polymethyl methacrylate, polystyrene, polysulfone, cycloolefin polymer, amorphous polyolefin, cellulose ester, and the like are used. A known retardation film obtained by producing while stretching in a uniaxial direction can be considered.

  In addition, as a material for the first retardation layer 102 and the second retardation layer 104, secondly, a liquid crystal obtained by performing an alignment treatment on the alignment layer, forming a liquid crystal on the alignment layer, aligning it, and then crosslinking it. A membrane is conceivable. As the material and alignment treatment of the alignment layer, a known polymer such as polyvinyl alcohol, polyimide, gelatin, carboxymethyl cellulose, polyethylene, polypropylene, and polycarbonate is rubbed, or azobenzene, cinnamoyl, coumarin, Examples include a method of irradiating a photo-alignment material such as chalcone or a benzophenone derivative or polyimide with polarized ultraviolet rays.

Since the retardation film has a thickness of about several tens of micrometers, it can also function as a base material or a protective film. On the other hand, the thickness of the liquid crystal film is several μm and can be made very thin as compared with the retardation film.
These retardation films and liquid crystal films may be used for both the first retardation layer 102 and the second retardation layer 104, or one of them may be used.

  For example, when both the first retardation layer 102 and the second retardation layer 104 are formed of a retardation film, an inexpensive and durable anti-counterfeit medium 20 can be obtained. Conversely, when both the first retardation layer 102 and the second retardation layer 104 are formed of liquid crystal films, a very thin anti-counterfeit medium 20 can be obtained. Further, when the retardation film is used as the outermost layer of the anti-counterfeit medium 20 and the liquid crystal film is used as the other layer of the first retardation layer 102 and the second retardation layer 104, it does not become too thick. Also, a retardation film can be used as a protective film. Conversely, when a liquid crystal film is used for the outermost layer of the anti-counterfeit medium 20 and a retardation film is used for the other film, the retardation film can be used like a substrate, so that it is suitable for processing. There is a feature that improves.

These liquid crystal films and retardation films can be made to form a latent image, which is one of the objects of the present invention, by patterning and partially varying the retardation value. Since it is difficult to individually form the first retardation layer 102 and the second retardation layer 104 on the entire surface of the forgery prevention medium 20, it is the gist of the present invention that a latent image appears by another method. is there.
The first reflective layer 103 and the second reflective layer 105 are necessary to make this latent image appear. Although a detailed mechanism of the appearance of the latent image will be described later, the light reflected by the first reflective layer 103 and only passing through the first retardation layer 102 and reflected by the second reflective layer 105 are reflected on the first retardation layer 102. And a latent image is formed using a difference in properties between the light passing through both the second retardation layer 104 and the second retardation layer 104.

(Configuration of the first reflective layer 103 and the second reflective layer 105)
As a method for forming the first reflective layer 103 and the second reflective layer 105, first, as a sheet serving as a substrate, for example, a film of polyethylene terephthalate, polypropylene, polycarbonate, polymethyl methacrylate, polyethylene or the like is prepared. Next, for example, polyvinyl alcohol, methyl cellulose, ethyl cellulose, cellulose acetate, polystyrene, polyvinyl chloride, linear saturated polyester, polymethyl methacrylate, polyethyl methacrylate, or other methacrylic resin homopolymer or copolymer as a release layer on this film A polymer material that dissolves in water or an organic solvent made of a single or copolymer resin such as acrylic, styrene, silicon, or polyisobutyl is applied and dried. Although the thickness of a film may be about 3-100 micrometers, More preferably, it is about 4.5-25 micrometers. The thickness of the release layer after drying is adjusted according to the characteristics of the material so as to have appropriate transfer suitability and to give a predetermined peel strength and cutability, but is preferably about 0.5 to 20 μm. .

A reflective layer is formed on the release layer thus formed. As a method for forming the reflective layer, a vapor deposition method such as a vacuum deposition method or a sputtering method may be used, or a printing method in which an ink containing a reflective material such as metal flakes is applied and then dried may be used. .
When the vapor deposition method is used, examples of the material include metals or alloys such as aluminum, chromium, nickel, silver, gold, copper, tin, magnesium, zinc, iron, and titanium. Aluminum, silver, chromium, nickel, etc., which have less wavelength dependency and high reflectivity, are more preferable than gold, copper, etc., which have wavelength dependency of reflected light, and the film thickness may be about 400 to 1200 angstroms. If necessary, the adhesion between the release layer and the reflective layer may be enhanced by introducing plasma or a magnetic field into the gas phase.

When the printing method is used, the reflecting material is not particularly limited, and the metal flakes include metals, alloys such as aluminum, chromium, nickel, silver, gold, copper, tin, magnesium, zinc, iron, and titanium. Other materials that can be used include pearls and other flaky or spherical materials, which can be used as transparent resins such as various thermoplastic polymer materials, thermosetting polymer materials, and UV curable materials. After being dispersed, it is applied, dried and cured to form. In the printing method, it is also possible to serve as both the reflective layer and the release layer by dispersing the reflective material in the release layer material.
A reflective transfer foil is formed by forming an adhesive layer on the reflective layer thus provided. This adhesive layer is formed using an adhesive that is in close contact with the adherend forming the first reflective layer 103 and the second reflective layer 105. For convenience of processing, there is no tack at room temperature, and it melts by heating. Adhesives are desirable.

  The first reflective layer 103 and the second reflective layer 105 are formed using the reflection transfer foil thus created. For example, the thermal transfer formed by peeling off the base of the reflective transfer foil after heating and transferring a predetermined thermal dot while passing between the line thermal head and the pressure roll after overlapping the reflective transfer foil with the adherend A pattern forming method can be applied by a head method or a hot stamping method in which a base material of a reflective transfer foil is peeled off after pressing a die heated and superposed on an adherend. Alternatively, the reflective transfer foil may be patterned by removing the silver portion by laser ablation using a high-power laser and then transferring the pressure by passing it between heated pressure rolls. These methods have an advantage that a relatively free pattern can be formed.

  Since the first reflective layer 103 is closer to the observation surface than the second reflective layer 105, it is essential that the first reflective layer 103 be provided in a patterned manner. However, the second reflective layer 105 may be provided on the entire surface, or partially. It may be provided. Forming the second reflective layer 105 on the entire surface has the advantage of lowering the cost because the configuration is further simplified, and forming partly has the advantage of improving the design because the silver pattern can be visually recognized with the naked eye. There is.

  However, the first reflective layer 103 and the second reflective layer 105 are preferably formed by the same method as much as possible. The reason for this is that when a silver transfer foil is patterned by a thermal head method, even if a solid pattern is formed, it often has a unique texture due to spread thermal dots. In this way, when the silver transfer foil is patterned by the thermal head method to form the first reflective layer 103, the second reflective layer 105 is hot stamped when formed by the hot stamping method using a specific shape mold. This is because the solid pattern is uniformly formed as a beautiful film, so that the boundary between the first reflective layer 103 and the second reflective layer 105 can be visually recognized at the time of visual observation.

It is preferable that the boundary is as hard to see as possible. Although not shown, a light scattering layer or a mesh pattern print may be provided on the first retardation layer 102 so that the boundary is difficult to see.
The light scattering layer may be provided by applying a white pigment in which a white pigment such as titanium oxide, silica filler, various waxes and the like are appropriately dispersed in a binder, a kneading mat, a chemical mat, a sand blasting method, etc. It may be provided by a method such as bonding together a matte-processed plastic film such as a matte PET film manufactured in (1).

The mesh pattern printing can be provided by various printing methods such as offset printing, screen printing, flexographic printing, gravure printing, ink jet printing, and pattern transfer of various transfer foils, etc., printing fine line mesh patterns to make the boundary less noticeable do it.
When the polarizing plate 10 is superimposed on the anti-counterfeit medium 20 thus created, a latent image of a monochrome image appears, and when the polarizing plate 10 is rotated, the effect of switching the pattern negative / positive can be confirmed.

(Configuration of anti-counterfeit medium 30 with cholesteric layer and black absorption layer 106)
The anti-counterfeit medium 30 shown in FIG. 2 is obtained by adding a cholesteric layer and a black absorbing layer 106 to the anti-counterfeit medium 20 shown in FIG. 1 and incorporating a color shift function. In principle, the cholesteric layer and the black absorption layer 106 are preferably provided on the side opposite to the observation surface of the anti-counterfeit medium 30. That is, when the structure of the anti-counterfeit medium 20 in FIG. 1 is a basic structure, it is preferably formed on the first reflective layer 103 side that is the observation surface and the second reflective layer 105 side across the basic structure. Further, it is preferable that the cholesteric layer is formed so as to be sandwiched between the basic structure and the black absorption layer.

  The cholesteric layer is a layer made of cholesteric liquid crystal. Cholesteric liquid crystals selectively reflect light with a wavelength corresponding to the pitch of the twisted structure because the refractive index of light periodically varies along the helical axis of cholesteric liquid crystals having a helical molecular structure. . Therefore, it is possible to create a desired reflection color by controlling the pitch of the twisted structure. Then, by aligning these cholesteric liquid crystals, the respective molecules form a layer and are arranged uniformly, and the reflected lights strengthen each other to reflect the color light as a whole. That is, the cholesteric layer functions as a color change layer that reflects desired color light.

By disposing a black absorption layer having absorption in the visible light region on the back of the basic structure of the anti-counterfeit medium 30 (that is, the anti-counterfeit medium 20 in FIG. 1), the transmitted light is absorbed and the reflected light is more By emphasizing, so-called cholesteric color light can be confirmed.
Since the aligned cholesteric liquid crystal molecules have a helical structure, the reflected light is right-handed circularly polarized light or left-handed circularly polarized light.
For this reason, the reflected light can be blocked by placing an appropriate circularly polarizing filter on the cholesteric liquid crystal layer.

(Configuration of cholesteric layer and black absorbing layer 106)
The cholesteric liquid crystal forming the cholesteric layer can be aligned by forming a layer on the alignment film. That is, it is possible to align by forming an alignment film on the substrate and forming a cholesteric liquid crystal layer on the alignment film.
As this alignment film, a film obtained by rubbing a coating film of polyvinyl alcohol or polyimide can be used.

  Rubbing is possible using, for example, cotton or velvet. Moreover, it can also be made to orient in the direction of the shearing force by apply | coating, applying a shearing force. Or after forming a cholesteric liquid crystal layer, it can also align by applying a shearing force. Further, the formed cholesteric liquid crystal layer can be oriented by irradiating polarized laser light, applying electrolysis or a magnetic field.

  This cholesteric liquid crystal layer is formed by applying a liquid crystal solution in which a liquid crystal material having a nematic structure or a smectic structure, a chiral material, a photopolymerizable polyfunctional compound, and a polymerization initiator are mixed, and irradiating the coating film with ultraviolet rays. be able to. At this time, the chiral material bonds the liquid crystal materials to form the helical structure. Further, the photopolymerizable polyfunctional compounds are polymerized and cured to fix the cholesteric liquid crystal.

Instead of the liquid crystal material and the chiral material, an optical isomer liquid crystal material having an asymmetric carbon atom in the molecule is used, and the optical isomer liquid crystal material, the photopolymerizable polyfunctional compound and the polymerization initiator are mixed and applied. It is also possible to form a cholesteric liquid crystal layer by irradiating with ultraviolet rays.
In addition, the liquid crystal solution can be directly applied onto a substrate to form a cholesteric liquid crystal layer, or after forming a cholesteric liquid crystal layer on another support, an adhesive is used to form the substrate. The cholesteric liquid crystal layer may be formed on the substrate by bonding or transferring using a method such as laminating.

Next, as the photopolymerizable polyfunctional compound, a polymerizable functional group, a polycondensable functional group, or a monomer or oligomer having two or more functional groups effective for polyaddition in the molecule can be used. In addition to this photopolymerizable polyfunctional compound, a monofunctional monomer or oligomer can be used in combination. Examples of radical photopolymerizable polyfunctional monomers include trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, and the like. Can do.
Examples of the radical photopolymerizable polyfunctional oligomer include polyurethane polyacrylate, epoxy resin polyacrylate, acrylic polyol polyacrylate, and the like.

  Examples of the radical photopolymerizable monofunctional monomer include alkyl (C1 to C18) (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, alkylene (C2 to C4) glycol (meth) acrylate, In alkoxy (C1-C10) alkyl (C2-C4) (meth) acrylate, polyalkylene (C2-C4) glycol (meth) acrylate, alkoxy (C2-C10) polyalkylene (C2-C4) glycol (meth) acrylate, etc. Can be mentioned. Moreover, an aromatic epoxy compound, an alicyclic epoxy compound, and a glycidyl ester compound can be used, and a three-dimensional crosslinkable liquid crystal polyorganosiloxane can also be used.

  Subsequently, as the polymerization initiator, a radical photopolymerization initiator or a cationic photopolymerization initiator can be used. In addition to these photopolymerization initiators, a sensitizer and a peroxide can be used in combination. As the radical photopolymerization initiator, known ones such as acetophenone series such as α-hydroxyacetophenone series and α-aminoacetophenone series, benzoin ether series, benzyl ketal series, α-dicarbonyl series, α-acyl oxime ester series, etc. Can be applied. Specifically, α-aminoacetophenone, acetophenone diethyl ketal, benzyl dimethyl ketal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methylphenylpropanone, benzophenone, Michler's ketone, isopropylthioxanthone, etc. can be applied. It is also possible to use benzophenone and N-methyldiethanolamine in combination.

As the cationic photopolymerization initiator, conventionally known ones can be used without particular limitation, and it is preferable to use them together with known sensitizers and peroxides as appropriate.
For example, allyl iodonium salt-α-hydroxyacetophenone, triallyl sulfonium salt, metallocene compound-peroxide combined system, metallocene compound-thioxanthone combined system, metallocene compound-anthracene combined system, etc. are applied as cationic photopolymerization initiators. can do.

And as a coating device used in applying a liquid crystal solution in which these liquid crystal substance, chiral substance, photopolymerizable polyfunctional compound and polymerization initiator are mixed, a comma coater, a micro gravure coater, an offset, or the like may be used. it can. The thickness of the cholesteric liquid crystal layer may be 0.5 to 20 μm. Preferably it is 2-10 micrometers.
The cholesteric liquid crystal formed in this way may be directly formed on the black absorption layer as long as it can be formed by direct alignment on the black absorption layer and can obtain adhesion. When difficult, after forming on another base material, after laminating | stacking on a black absorption layer on both sides of an adhesive agent, you may form by peeling another base material.

  The black absorption layer needs to absorb at least visible light wavelengths. When forming this, for example, there is a method of forming a film by printing a smear ink for printing in which a carbon black pigment is dispersed in various binders such as a polymer resin by a gravure printing method, a screen printing method, an offset printing method, or the like. . Further, instead of the carbon black pigment, an organic black pigment typified by aniline black, perylene black or the like, or an inorganic black containing chromium, manganese, iron, cobalt, copper, etc., titanium black or the like may be used. Alternatively, black obtained by subtractive color mixing by mixing various color pigments such as cyan, magenta, and yellow may be used. The film thickness of the black absorption layer depends on the content of the black pigment, but is generally about 0.3 μm to 30 μm.

(Viewing method of cholesteric color)
In order to visually recognize the cholesteric color generated by the cholesteric layer and the black absorption layer 106 formed in this way, a portion where neither the first reflective layer 103 nor the second reflective layer 105 is formed is necessary. It is necessary to visually recognize the light that has passed through the layer 102 and the second retardation layer 104. The light that has passed through the first retardation layer 102 and the second retardation layer 104 becomes linearly polarized light, and the direction of the polarization is either the same as or perpendicular to the orientation axis direction of the first retardation layer 102. . The direction of this polarized light depends on the rotational direction of the circularly polarized light reflected by the cholesteric layer (106). When the cholesteric layer (106) reflects the right circularly polarized light, the first retardation layer 102 is used. When the one that reflects the left circularly polarized light is used, it is orthogonal to the orientation axis direction of the first retardation layer 102.

Since the cholesteric color becomes linearly polarized light in this way, the polarizing plate 10 that is a linearly polarizing plate used for visually recognizing a monochrome latent image superimposed in the vicinity of the first retardation layer 102 of the anti-counterfeit medium 30 is from a distance. When observing a cholesteric color, the presence or absence of colored light can be confirmed by using the polarizing plate 10 which is the same linear polarizing plate.
2 illustrates the case of performing color shift by using a cholesteric layer using cholesteric liquid crystal as a material, but it does not have a function of circularly polarized light reflection such as a multilayer film or a printing layer containing a pearl pigment. There are other materials having a color shift effect, and a layer made of these materials may be replaced with a cholesteric layer, or another color printing layer having no color shift effect may be provided.

(Principle of appearance of latent image)
Next, the principle that a latent image appears in the forgery prevention media 20 and 30 shown in FIGS. 1 and 2 will be described.
3 and 4 are cross-sectional views in which each layer constituting the anti-counterfeit medium 30 in FIG. 2 is divided for each layer in order to explain the principle that a latent image appears in the anti-counterfeit media 20 and 30. It shows how various types of light change as they penetrate each layer.

  In FIG. 3, reference numeral 100 denotes the anti-counterfeit medium 30 and the polarizing plate 101, and the polarizing plate 101 is overlaid on the anti-counterfeit medium 30 in the 0 degree direction. The polarizing plate 101 in this state is referred to as a polarizing plate (A). In FIG. 3, reference numeral 102 denotes a first retardation layer, 103 denotes a first reflection layer, 104 denotes a second retardation layer, 105 denotes a second reflection layer, and 106 denotes a cholesteric layer and a black absorption layer. The positional relationship between the cholesteric layer and the black absorbing layer is such that the cholesteric layer is sandwiched between the black absorbing layer and the second reflective layer 105.

In FIG. 3, reference numeral 107 denotes a mark for explaining the transmission axis direction of the polarizing plate (A). In the direction of the transmission optical axis of the polarizing plate (A) in a state of being superimposed on the anti-counterfeit medium 30 in the 0 degree direction. is there. Similarly, 108 indicates the orientation axis direction of the first retardation layer 102, and 109 indicates the orientation axis direction of the second retardation layer 104.
First, referring to FIG. 3, a description will be given of changes in light in each part when natural light is incident on an area where the first reflective layer 103 exists.

  When natural light 110 is incident on the polarizing plate (A) 101 in the area where the first reflective layer 103 exists, the natural light 110 passes through the polarizing plate (A) 101 in a state of being superimposed on the forgery prevention medium 30 in the 0 degree direction. The linearly polarized light (A) 111 is obtained. When the linearly polarized light (A) 111 passes through the first retardation layer 102, the linearly polarized light (A) 111 becomes circularly polarized light (A) 112 that has passed through the first retardation layer 102. Subsequently, the circularly polarized light (A) 112 is reflected by the first reflective layer 103, and the circularly polarized light (A) 112 becomes the circularly polarized light (B) 113 reflected by the first reflective layer 103. Since this reflection is fixed-end reflection, the rotational direction of the circularly polarized light (B) 113 is reversed from that of the circularly polarized light (A) 112 when the phase is shifted by 180 degrees. When the circularly polarized light (B) 113 passes through the first retardation layer 102 again, the circularly polarized light (B) 113 becomes linearly polarized light (B) 114 that has passed through the first retardation layer 102. As shown in the figure, the polarization axis of this linearly polarized light (B) 114 is shifted from the linearly polarized light (A) 111 by 90 degrees.

Therefore, when the linearly polarized light (B) 114 passes through the polarizing plate (A) 101, the linearly polarized light (B) 114 becomes the observation light (A) 115 that has passed through the polarizing plate (A) 101. ) Since it is orthogonal to the transmission axis direction of 101, it hardly transmits, and the observation light (A) 115 becomes dark.
Similarly, in FIG. 3, a change in light in each part when natural light is incident on an area where the first reflective layer 103 does not exist and the second reflective layer 105 exists will be described.

  When natural light 110 is incident on the polarizing plate (A) 101 in an area where the first reflective layer 103 is not present and the second reflective layer 105 is present, the natural light 110 passes through the polarizing plate (A) 101 as described above. By doing so, it becomes linearly polarized light (A) 111 and further passes through the first retardation layer 102 to become circularly polarized light (A) 112. Subsequently, when the circularly polarized light (A) 112 passes through the second retardation layer 104, the circularly polarized light (A) 112 becomes linearly polarized light (Cα) 116. When the linearly polarized light (Cα) 116 is reflected by the second reflective layer 105, the linearly polarized light (Cα) 116 becomes the linearly polarized light (Cβ) 117 reflected by the second reflective layer 105. In the generated fixed end reflection, even if the phase inversion of 180 degrees occurs, the linearly polarized light is not affected. Therefore, the polarization direction does not change between the linearly polarized light (Cα) 116 and the linearly polarized light (Cβ) 117 as illustrated. When this linearly polarized light (Cβ) 117 passes through the second retardation layer 104 again, the linearly polarized light (Cβ) 117 becomes circularly polarized light (C) 118 that has passed through the second retardation layer 104, but this circularly polarized light (C) ) 118 is circularly polarized light in the same rotational direction as the circularly polarized light (A) 112, and then when the circularly polarized light (C) 118 passes through the first retardation layer 102, the circularly polarized light (C) 118 becomes the first phase difference. The linearly polarized light (D) 119 that has passed through the layer 102 becomes the same, and this linearly polarized light (D) 119 has the same polarization direction as that of the linearly polarized light (A) 111. The passing observation light (B) 120 coincides with the transmission axis direction of the polarizing plate (A) 101, and the observation light (B) 120 becomes brighter. Therefore, the difference in brightness between the observation light (A) 115 and the observation light (B) 120 becomes a contrast, and the monochrome image can be visually recognized as a latent image.

Next, in FIG. 3, an area where the natural light incident on the anti-counterfeit medium 30 is observed as reflected light reflected by the cholesteric layer (106) will be described.
When natural light 110 is incident on the polarizing plate (A) 101, the natural light 110 passes through the polarizing plate (A) to become linearly polarized light (A) 111 and further passes through the first retardation layer 102 as described above. Becomes circularly polarized light (A) 112, and then passes through the second retardation layer 104 to become linearly polarized light (Cγ) 121.

  The linearly polarized light (Cγ) 121 is exactly the same light as the linearly polarized light (Cα) 116 in which the circularly polarized light (A) 112 has passed through the second retardation layer 104, but the linearly polarized light (Cγ) 121 is converted into the cholesteric layer (106 The portion that is transmitted without being reflected by () is absorbed by the black absorption layer (106). When the circularly polarized light (D) 122 reflected from the cholesteric layer (106) passes through the second retardation layer 104 again, the linearly polarized light (E) 123 through which the circularly polarized light (D) 122 passes through the second retardation layer 104. It becomes. When the cholesteric layer (106) reflects right circularly polarized light, the polarization direction of the linearly polarized light (E) 123 coincides with the orientation axis direction of the first retardation layer 102, and the cholesteric layer (106). Is an object that reflects left circularly polarized light, it is orthogonal to the orientation axis direction of the first retardation layer 102. Therefore, what is shown is a diagram when right circularly polarized light is reflected from the cholesteric layer (106). When this linearly polarized light (E) 123 passes through the first retardation layer 102, the linearly polarized light (E) 123 becomes linearly polarized light (F) 124 that has passed through the first retardation layer 102. This linearly polarized light (F) The polarization direction 124 matches the polarization direction of the linearly polarized light (E) 123 regardless of the polarization direction of the linearly polarized light (E) 123, and the angle formed with the transmission axis direction of the polarizing plate (A) 101 is 45. Degree. Therefore, when this linearly polarized light (F) 124 passes through the polarizing plate (A) 101, the linearly polarized light (F) 124 becomes observation light (C) 125 that has passed through the polarizing plate (A) 101, and this observation light (C) Although 125 is a medium brightness that is neither bright nor dark, it is possible to confirm the cholesteric color and color shift phenomenon peculiar to the cholesteric layer (106).

FIG. 4 shows an anti-counterfeit medium 30 having exactly the same structure as that shown in FIG.
In FIG. 4, reference numeral 200 denotes the anti-counterfeit medium 30 and the polarizing plate 201. The polarizing plate 201 is overlaid on the anti-counterfeit medium 30 in the 45 degree direction, and the polarizing plate 201 in this state is displayed. Let it be a polarizing plate (B). Also, 207 in FIG. 4 is the direction of the transmitted optical axis of the polarizing plate (B) in a state of being superimposed on the forgery prevention medium 30 in the 45 degree direction.

First, in FIG. 4, a description will be given of changes in light in each part when natural light is incident on an area where the first reflective layer 103 exists.
When the linearly polarized light (G) 211 having passed through the polarizing plate (B) 201 in a state where the natural light 110 is superimposed on the anti-counterfeit medium 30 in the 45 degree direction passes through the first retardation layer 102, the linearly polarized light (G) Becomes the linearly polarized light (H) 212 that has passed through the first retardation layer 102. When the linearly polarized light (H) 212 is reflected by the first reflective layer 103, the linearly polarized light (H) 212 becomes the linearly polarized light (I) 213 reflected by the first reflective layer 103. In the generated fixed end reflection, even if the phase inversion of 180 degrees occurs, the linearly polarized light is not affected. Therefore, the polarization direction does not change between the linearly polarized light (I) 213 and the linearly polarized light (G) 212 as illustrated.

  When the linearly polarized light (I) 213 passes through the first retardation layer 102 again, the linearly polarized light (I) 213 becomes linearly polarized light (J) 214 that has passed through the first retardation layer 102. At this time, since the polarization direction of the linearly polarized light (I) 213 and the alignment axis direction of the first retardation layer 102 coincide with each other, the linearly polarized light (J) 214 and the linearly polarized light (I) 213 are in the polarization direction as illustrated. There is no change. Further, since the polarization direction coincides with the transmission optical axis direction of the polarizing plate (B) 201, the observation light (D) 215 in which the linearly polarized light (J) 214 passes through the polarizing plate (B) 201 looks bright.

Similarly, in FIG. 4, changes in light in each part when natural light is incident on an area where the first reflective layer 103 does not exist and the second reflective layer 105 exists will be described.
When natural light 110 is incident on the polarizing plate (B) 201 in an area where the first reflective layer 103 is not present and the second reflective layer 105 is present, the natural light 110 passes through the polarizing plate (B) 201 as described above. By doing so, it becomes linearly polarized light (G) 211 and further passes through the first retardation layer 102 to become linearly polarized light (H) 212. Subsequently, when the linearly polarized light (H) 212 passes through the second retardation layer 104, the linearly polarized light (H) 212 becomes circularly polarized light (Eα) 216 that has passed through the second retardation layer 104. When the circularly polarized light (Eα) 216 is reflected by the second reflective layer 105, the circularly polarized light (Eα) 216 becomes circularly polarized light (F) 217 reflected by the second reflective layer 105. This reflection is reflected at the fixed end. Therefore, when the phase is shifted by 180 degrees, the circularly polarized light (F) 217 reverses the turning direction of the circularly polarized light (Eα) 216. When the circularly polarized light (F) 217 passes through the second retardation layer 104, the circularly polarized light (F) 217 becomes linearly polarized light (K) 218 that has passed through the second retardation layer 104, and the linearly polarized light (K) 218 The polarization direction is orthogonal to the linearly polarized light (H) 212 and is also orthogonal to the orientation axis direction of the first retardation layer 102. When this linearly polarized light (K) 218 passes through the first retardation layer 102, the linearly polarized light (K) 218 becomes linearly polarized light (L) 219 that has passed through the first retardation layer 102, but linearly polarized light (L) 219. Is the same as that of the linearly polarized light (K) 218 as shown in the figure, and is therefore orthogonal to the transmission axis direction of the polarizing plate (B) 201. Therefore, the observation light (E) 220 in which the linearly polarized light (L) 219 has passed through the polarizing plate (B) 201 looks dark.

Therefore, the difference in brightness between the observation light (D) 215 and the observation light (E) 220 becomes a contrast, and the monochrome image can be visually recognized as a latent image.
In addition, the observation light (A) 115 in FIG. 3 is dark, whereas the observation light (D) 215 in FIG. 4 is bright, and the observation light is observed even though the same position of the forgery prevention medium 30 is observed. The brightness is reversed. Similarly, the observation light (B) 120 in FIG. 3 is bright, while the observation light (E) 220 in FIG. 4 is dark, and the observation light (B) 120 is observed even though the same position of the anti-counterfeit medium 30 is observed. The brightness of the light is reversed.

Therefore, in FIGS. 1 and 2, when the polarizing plate 10 is rotated to the position 0 degree and the position 45 degrees with respect to the anti-counterfeit medium 20 or 30, the negative / positive of the monochrome image as the latent image is reversed. I understand.
FIG. 5 is a graph in which the intensity of reflected light is individually normalized for the observation lights (A) to (F). How the brightness of each observation light changes when the polarizing plate 10 is further rotated. It explains what to do. Note that the observation light (F) represents observation light observed in the area where the reflected light from the cholesteric layer (106) is observed in FIG.

  In FIG. 5, the observation light (A) 115 and the observation light (E) 220 indicated by solid lines are the darkest when the angle of the polarizing plate 10 with respect to the anti-counterfeit medium 30 is 0 degrees, 90 degrees, and 180 degrees, 45 degrees, Brightest at 135 degrees. Conversely, the observation light (B) and the observation light (D) indicated by broken lines are brightest at 0 °, 90 °, and 180 °, and darkest at 45 ° and 135 °. This brightness difference becomes contrast and repeats negative and positive. The observation light (C) and the observation light (F) indicated by the alternate long and short dash line will be described later.

Next, in FIG. 4, changes in light in each part when natural light is incident in an area where the reflected light from the cholesteric layer (106) is observed will be described.
Similarly to the above, natural light 110 becomes linearly polarized light (G) 211 by passing through the polarizing plate (B) 201, and further becomes linearly polarized light (H) 212 by passing through the first retardation layer 102, The linearly polarized light (H) 212 passes through the second retardation layer 104 and becomes circularly polarized light (Eβ) 221. The circularly polarized light (Eβ) 221 is exactly the same light as the circularly polarized light (Eα) 216 in which the linearly polarized light (H) 212 has passed through the second retardation layer 104, but the circularly polarized light (Eβ) 221 is the cholesteric layer (106 The portion that is transmitted without being reflected by () is absorbed by the black absorption layer (106). When the circularly polarized light (F) 222 reflected from the cholesteric layer (106) passes through the second retardation layer 104 again, the linearly polarized light (M) in which the circularly polarized light (F) 222 passes through the second retardation layer (104). 223. The polarization direction of the linearly polarized light (M) 223 is the same as the orientation axis direction of the first retardation layer 102 when the cholesteric layer (106) reflects right circularly polarized light as in FIG. If the cholesteric layer (106) reflects left circularly polarized light, it is perpendicular to the orientation axis direction of the first retardation layer. Therefore, FIG. 4 shows a case where right circularly polarized light is reflected from the cholesteric layer (106). When this linearly polarized light (M) 223 passes through the first retardation layer 102, the linearly polarized light (M) 223 becomes linearly polarized light (N) 224 that has passed through the first retardation layer 102. This linearly polarized light (N) The polarization direction of 224 coincides with the polarization direction of the linearly polarized light (M) 223 and the transmission axis direction of the polarizing plate (B) 201 regardless of the polarization direction of the linearly polarized light (M) 223.

Therefore, when this linearly polarized light (N) 224 passes through the polarizing plate (B) 201, the linearly polarized light (N) 224 becomes observation light (F) 225 that has passed through the polarizing plate (B) 201, and this observation light (F) 225 becomes brighter, and the cholesteric color and color shift phenomenon peculiar to the cholesteric layer (106) can be confirmed firmly.
Here, the observation light (C) and the observation light (F) indicated by broken lines in FIG. 5 will be described. In the light path through which the observation light (C) and the observation light (F) are observed, the characteristic of the light (that is, the observation light) that is finally viewed is reflected from the fixed cholesteric layer (106). Because it depends on light, when the cholesteric layer (106) reflects right circularly polarized light, linearly polarized light having a polarization direction of 45 degrees is fixedly emitted as shown in FIGS. Therefore, as shown by the broken line in FIG. 5, the angle of the polarizing plate 10 with respect to the forgery prevention medium 30 is the brightest at 45 degrees and the darkest at 135 degrees. When the cholesteric layer (106) reflects left-handed circularly polarized light, linearly polarized light with a polarization direction of 45 degrees appears, so the graph is inverted so that 135 degrees is the brightest and 45 degrees is the darkest. become.

(Example of observation of anti-counterfeit media)
FIG. 6 to FIG. 9 specifically explain what effect can be observed when the polarizing plate 10 is actually superimposed on the forgery prevention medium 30. 6 and 7 are top views of the anti-counterfeit medium 30 having a cholesteric configuration, and explain the patterns of the first reflective layer 103 and the second reflective layer 105 shown in FIG. In FIG. 6, a character pattern “TP” is formed. FIG. 7 shows the pattern of the second reflective layer 105 in black, and the white part is “P” of the first reflective layer 103 forming the character pattern “TP” as shown in FIG. The cholesteric layer and the cholesteric layer of the black absorption layer 106 can be seen from the missing portion. In other words, the first reflective layer 103 is a layer having a letter shape of “T” and “P”, and the second reflective layer 105 is formed on the entire surface of the anti-counterfeit medium 30 and only a semicircular portion of “P”. It becomes the layer which consists of a shape from which was removed.

FIG. 8 is a top view when the polarizing plate 10 is overlapped with the anti-counterfeit medium 30 at an angle of 45 degrees. Only the portion where the polarizing plate 10 is overlapped is formed with a character pattern “TP”. One reflective layer 103 can be visually recognized. The cholesteric layer and the black absorption layer 106 can visually recognize a cholesteric color.
FIG. 9 is obtained by further rotating the angle of the polarizing plate 10 superimposed on the anti-counterfeit medium 30 in FIG. 8 by 45 degrees. As shown in FIG. 9, the latent image appears only in the portion where the polarizing plate 10 is overlapped, and the latent images of the portion where the first reflective layer 103 is formed and the portion where the second reflective layer 105 is formed are displayed. Compared to FIG. 8, the image is negative-positive inverted. The cholesteric layer and the black absorbing layer 106 can visually recognize a cholesteric color, and the cholesteric color in this case is different in brightness from FIG.

  As described above, the observation lights (A), (B), (D), and (E) confirm the appearance of the monochrome latent image and the negative / positive reversal phenomenon by rotating the linear polarizing plate 10 on the anti-counterfeit medium 30 and rotating it. it can. On the other hand, the observation lights (C) and (F) that can be obtained without the natural light 110 passing through the linear polarizing plate 10 are prepared with the linear polarizing plate 10 at hand, and the linear polarizing plate 10 from a little away. Even if it is observed through the above, it can be confirmed that the brightness changes by rotating the linearly polarizing plate 10, and therefore a remote authenticity determination function is also provided.

(Double-sided latent image forgery prevention medium)
Next, a forgery prevention medium capable of observing different latent images from both sides will be described.
FIG. 10 is an example of the double-sided latent image forgery prevention medium 40 in which the third retardation layer 301 is further added to the basic configuration of the forgery prevention medium 20 of FIG. The third retardation layer 301 is provided on the second reflection layer 105 side of the anti-counterfeit medium 20, and the latent image can be observed from both the first retardation layer 102 side and the third retardation layer 301 side. ing. In other words, it incorporates a function that allows different images to be confirmed on both sides of the anti-counterfeit medium and reverses the turning direction when circularly polarized light is transmitted.

  The basic principle of the double-sided latent image forgery prevention medium 40 is as described with reference to FIGS. 3 and 4, and an image is formed by an area passing through one phase difference layer and an area passing through two phase difference layers. . The second reflective layer 105 also serves as the second reflective layer on both observation surfaces. At this time, if the third retardation layer 301 is misaligned by 45 degrees with the second retardation layer 104, In addition, the angle formed by the alignment axes of the first retardation layer 102 and the third retardation layer 301 may be 0 degree or 90 degrees.

The suitable pattern of the 1st reflective layer 103 and the 2nd reflective layer 105 of the double-sided latent image forgery prevention medium 40 can be illustrated to FIG. 11 and FIG.
FIG. 11 shows the pattern of the first reflective layer 103 in black when viewed from the surface side where the first retardation layer 102 is the outermost surface, and represents the letters “TP”. FIG. 12 shows the pattern of the second reflective layer 105 when viewed from the surface side where the first retardation layer 102 is the outermost surface. The figure in which the letters “AL” are inverted vertically and horizontally are omitted. Pattern. The black-and-white reversal pattern of FIG. 12 is smaller than the pattern of FIG. 11, and when the black portion of FIG. 11 is superimposed on the black portion of FIG. For this reason, the entire surface looks silver when viewed from both sides.

  FIG. 13 shows a state in which the polarizing plate 10 is superimposed on the double-sided latent image forgery prevention medium 40 and is observed from the surface side where the first retardation layer 102 is the outermost surface. At this time, the characters “TP” appear as latent images. FIG. 14 similarly shows a state in which the polarizing plates 10 are overlapped, and is observed from the opposite side of the surface having the first retardation layer 102 as the outermost surface. At this time, an image in which the characters other than “AL” are negative-positive inverted appears as a latent image.

  In FIG. 10, when the surface side having the first retardation layer 102 as the outermost surface is the A surface and the surface side having the third retardation layer 301 as the outermost surface is the B surface, the incident light from the A surface is the first surface. An area passing through only one retardation layer 102 is referred to as an A-plane one-layer retardation area 302, and an area passing through the first retardation layer 102 and the second retardation layer 104 is referred to as an A-plane two-layer retardation area 303. Further, an area where incident light from the B surface passes only through the third retardation layer 301 is defined as a B surface one-layer retardation area 304, and an area through which the third retardation layer 301 and the second retardation layer 104 are transmitted is defined as a B surface 2. Let it be a layer retardation area 305. In addition, neither the first reflection layer 103 nor the second reflection layer 105 exists in the plane, and the incident light from the A surface or the B surface is incident on the first retardation layer 102, the second retardation layer 104, and the third retardation. An area that passes through all of the layers 301 is defined as a three-layer retardation area 306.

  In the configuration of FIG. 10, it is impossible to add a function accompanied by a color change by the cholesteric layer (106) as shown in FIG. 2, but when this three-layer retardation area 306 is overlapped with the cholesteric layer and circularly polarized light is passed through, Direction reversal occurs in the circularly polarized light swirling direction after passing through the angle formed by the orientation axes of the first retardation layer 102 and the third retardation layer 301. When the circularly polarized light passes through the three-layer retardation area 306 in which the angle formed by the orientation axes of the first retardation layer 102 and the third retardation layer 301 is 0 degree regardless of the rotation direction of the circularly polarized light reflected by the cholesteric layer. When the turning direction is reversed, and passes through the three-layer phase difference area 306 having an angle of 90 degrees, the circularly polarized light having the same turning direction remains unchanged.

  FIG. 15 explains the reason why this phenomenon occurs, and the reflection from the cholesteric layer in the transparent area where the angles formed by the orientation axes of the first retardation layer 102 and the third retardation layer 301 are 0 degrees and 90 degrees. It shows how the light changes, and in particular illustrates the case where the reflected light from the cholesteric layer is right circularly polarized.

  In FIG. 15, 307 is a third retardation layer (α) having a light distribution axis direction in which the angle formed with the orientation axis direction of the first retardation layer 102 is 0 degree, and 308 is the first retardation layer 102. The third retardation layer (β) having a light distribution axis direction in which the angle formed with the orientation axis direction is 90 degrees, 309 is the orientation axis direction of the third retardation layer (α) 307, and 310 is the third retardation layer. (Β) 308 orientation axis direction, 311 is a cholesteric layer and black absorbing layer that reflects right circularly polarized light, 312 is right circularly polarized light that is reflected on the surface of the cholesteric layer, 313 is right circularly polarized light that passes through the first retardation layer 102 The linearly polarized light (O) and 314 are linearly polarized light (P) obtained by passing the linearly polarized light (O) 313 through the second retardation layer 104. 315 is circularly polarized light (G) in which the linearly polarized light (P) 314 has passed through the third retardation layer (α) 307, 316 is circularly polarized light in which the linearly polarized light (P) 314 has passed through the third retardation layer (β) 308 (H) 316.

  Since the polarization direction of the linearly polarized light (O) 313 through which the right circularly polarized light has passed through the first retardation layer 102 is orthogonal to the orientation axis direction 109 of the second retardation layer 104, the linearly polarized light (O) 313 is The polarization direction of the linearly polarized light (P) 314 that has passed through the two phase difference layer 104 is the same as the polarization direction of the linearly polarized light (O) 313. The linearly polarized light (P) 314 has the surface of the cholesteric layer 311 because the angle formed between the orientation axis direction (309) of the third retardation layer (α) 307 that passes through and the polarization direction is inclined 45 degrees clockwise. The right-handed circularly polarized light reflected by the light and the left-handed circularly polarized light whose direction of rotation is opposite. Conversely, when passing through the third retardation layer (β) 310 in which the angle between the polarization direction of the linearly polarized light (P) 314 and the orientation axis direction is inclined 45 degrees counterclockwise, the linearly polarized light (P) 314 is The circularly polarized light (H) 316 that has passed through the three phase difference layer (β) 308 becomes right circularly polarized light having the same turning direction as the right circularly polarized light reflected by the surface of the cholesteric layer 311.

  FIG. 16 illustrates the case where the reflected light of the cholesteric layer 311 in FIG. 15 is left circularly polarized light. 317 in FIG. 16 is a cholesteric layer and a black absorbing layer 318 that reflect left circularly polarized light. Left circularly polarized light reflected on the surface of the cholesteric layer 317, 319 is linearly polarized light (Q) in which the left circularly polarized light has passed through the first retardation layer 102, and 320 is linearly polarized light (Q) 319 that has passed through the second retardation layer 104. Linearly polarized light (R), 321 is circularly polarized light (I) in which linearly polarized light (R) 320 has passed through the third retardation layer (α) 307, and 322 is linearly polarized light (R) 320 in the third retardation layer (β). Circularly polarized light (J) that has passed through 308 is shown.

  Since the polarization direction of the linearly polarized light (Q) 319 through which the left circularly polarized light has passed through the first retardation layer 102 is the same as the orientation axis direction 109 of the second retardation layer 104, the linearly polarized light (Q) 319 is the second polarized light (Q) 319. The polarization direction of the linearly polarized light (R) 320 that has passed through the retardation layer 104 is the same as the polarization direction of the linearly polarized light (Q) 319. The linearly polarized light (R) 320 is reflected on the surface of the cholesteric layer 317 because the angle formed by the orientation axis direction 309 of the third retardation layer (α) 307 that passes through and the polarization direction is inclined 45 degrees counterclockwise. The left circularly polarized light and the right circularly polarized light whose direction of rotation is opposite are obtained. In contrast, when the angle between the polarization direction of the linearly polarized light (R) 320 and the orientation axis direction passes through the third retardation layer (β) 308 inclined 45 degrees clockwise, the linearly polarized light (R) 320 becomes the first The circularly polarized light (J) 322 that has passed through the three phase difference layer (β) 308 becomes left circularly polarized light having the same turning direction as the left circularly polarized light reflected by the surface of the cholesteric layer 317.

  As described above, the double-sided latent image forgery prevention medium 40 having the three-layer retardation area 306 shown in FIG. 10 overlaps the circularly polarized medium provided separately from the double-sided latent image forgery prevention medium 40 and filters Used as (circular polarization filter). And the change which arises by observing reflected light using a circularly polarized light filter can be utilized as an authenticity determination method.

(Anti-counterfeit medium with diffraction structure)
Next, a case where the reflection layer of the anti-counterfeit medium has a diffractive structure will be described.
FIG. 17 is a cross-sectional view illustrating an example of the anti-counterfeit medium 50 with a diffractive structure in which the first reflective layer 103 and the second reflective layer 105 of the anti-counterfeit medium 20 illustrated in FIG. 1 have a diffractive structure.
Here, in the anti-counterfeit media 20, 30 and 40 described so far, the first reflective layer 103 and the second reflective layer 105 are basically flat with no pattern in principle. The anti-counterfeit medium 50 with a diffractive structure shown in FIG. 17 intentionally forms a diffractive structure, and a diffractive reflective layer created by forming a reflective layer thereon using means such as vapor deposition is used as a first reflection. By using it as the layer 103 and the second reflective layer 105, a forgery prevention medium having a hologram effect is realized.

A diffractive structure is a fine unevenness having a light diffraction function. Light is reflected and diffracted by a light reflecting film provided along the surface, and the color and pattern of the reflected diffracted light changes depending on the viewing angle and direction. Therefore, copying and imitation are difficult and the anti-counterfeiting effect is excellent.
In FIG. 17, reference numeral 503 denotes a first diffraction reflection layer, and 505 denotes a second diffraction reflection layer. The first retardation layer 102 and the second retardation layer 104 are added thereto, and the first retardation layer 102, the first diffraction reflection layer 503, the second retardation layer 104, and the second diffraction reflection layer 505 are laminated in this order. What is the forgery prevention medium 50 with a diffraction structure.

The first diffractive reflective layer 503 and the second diffractive reflective layer 505 are formed by forming a diffractive structure between the light reflective layer and the release layer, and the materials of the first reflective layer 103 and the second reflective layer 105 described above, It is formed in substantially the same manner as the example of how to make it.
Specifically, it can be produced by the following process.
First, a matrix having a fine uneven pattern on the surface is prepared. The fine concavo-convex pattern is, for example, a concavo-convex pattern constituting a diffraction grating or hologram having a light diffraction function, and the height of the convex portion or the depth of the concave portion, and the pitch thereof are both about 0.1 to 10 μm. It is desirable. The image formed by diffracting the concave / convex pattern may be, for example, a character or a figure, and may include a logo mark or a machine reading code such as a barcode.

  Such a matrix can be created by, for example, forming a concavo-convex pattern by applying a photoresist on a substrate, exposing and developing in accordance with a two-beam interference method. Moreover, it can also create by forming the said uneven | corrugated pattern by apply | coating an electron beam resist on a board | substrate, drawing an electron beam, and developing. It can also be made by a method of etching silicon.

  In addition, by using the uneven pattern obtained in this way as an original plate, it is possible to create a matrix by repeating inversion. That is, a metal matrix can be produced by electroforming a metal such as nickel or iron on the surface of the concavo-convex pattern as an original plate and then peeling it off. Further, the original plate can be molded with a resin to produce a resin matrix. Although the mother die thus created can be used as it is, it is desirable to use it by winding it around a roll.

Next, a sheet serving as a base material for forming the diffractive structure is prepared. What is necessary is just to form this by the same material and the same procedure as the sheet | seat used as the base material used when forming the 1st reflective layer 103 and the 2nd reflective layer 105. FIG.
In addition, a release layer is provided on the base material, but the method of forming the release layer may be the same as the release layer used when forming the first reflective layer 103 and the second reflective layer 105.

Subsequently, a thermoplastic resin is applied as a concavo-convex pattern forming layer on the release layer and dried. The film thickness after drying may be a thickness that allows the concave / convex pattern to be accurately replicated. For this purpose, the thickness of the convex part or the concave part of the concave / convex pattern may be 1 to 10 times the depth. desirable. Generally, it may be 0.5-5 μm.
As the thermoplastic resin, acrylic resin, polycarbonate resin, styrene resin, acrylic / styrene copolymer resin, and the like can be used. An inorganic material containing silicate as a component can be used instead of the thermoplastic resin.

Then, the matrix is overlaid on the coating and pressed to replicate the irregular pattern of the matrix. For example, while continuously running a base sheet on which a thermoplastic resin film is formed, the thermoplastic resin is passed between a roll around which the matrix is wound and a paper roll, and pressed with both of these rolls. The concave / convex pattern can be transferred to the resin coating and replicated.
When pressing, the temperature and pressure of the roll around which the mother die is wound are relatively high from the viewpoint of reproducing the embossed shape, and it is better to emboss at a relatively high pressure, thus preventing adhesion to the embossed plate. For this purpose, the relationship is completely opposite. For this reason, it is desirable to press on the conditions of the temperature of 50-150 degreeC, and the pressure of 10-50 kg / cm < ² >.

  The release layer may be omitted if the uneven pattern forming layer has an appropriate adhesion to the base film, but the uneven pattern forming layer does not stick to the embossed plate at the time of embossing, and the first diffraction reflective layer Since it is necessary to peel off the base sheet after being formed as 503 and the second diffractive reflection layer 505, the adhesive force between the concavo-convex pattern forming layer and the base film is required to be very delicate. Therefore, it is preferable to control this adhesion by adjusting the material of the release layer and the processing conditions.

Next, a light reflecting film is formed along the uneven surface. The formation method and material of the light reflection film may be the same as the vapor deposition method when the formation method of the first reflection layer 103 and the second reflection layer 105 is described.
By installing the same adhesive as described in the method for producing the reflective transfer foil for forming the first reflective layer 103 and the second reflective layer 105 on the light reflective layer, the first diffractive reflective layer 503 and the second reflective layer 503 are provided. A diffraction reflection transfer foil for forming the diffraction reflection layer 505 is completed.

Unlike the first reflective layer 103 and the second reflective layer 105, the first diffractive reflective layer 503 and the second diffractive reflective layer 505 emit diffracted light that can be visually recognized by the naked eye. It ’s impossible. This is illustrated in FIG. 18 and FIG.
FIG. 18 shows a second diffractive reflection layer 505, in which a diffractive pattern 506 that can visually recognize a character pattern “Security” is provided on the entire surface as a diffraction image. After the second retardation layer 104 is formed thereon, a first diffractive reflection layer 503 as shown in FIG. 19 is formed. The first diffractive reflection layer 503 has only the character pattern “TP”, and 507 is a removal portion.

  The removal unit 507 may be formed by not transferring the diffraction reflection transfer foil by a thermal head method, or may be formed by not transferring by a hot stamping method using a “TP” character pattern mold. Alternatively, the first reflection layer 103 and the second reflection layer 105 may be formed in advance by laser ablation by irradiating the removal unit 507 with a high-power laser. For the same reason as described above, the first diffractive reflection layer 503 and the second diffractive reflection layer 505 are preferably provided in the same manner as much as possible in order to make the boundary difficult to understand. In the description of the first reflective layer 103 and the second reflective layer 105, formation of a light scattering layer or a mesh pattern printing is cited as a technique for making it difficult to visually recognize the boundary. However, the formation of the light scattering layer scatters diffracted light and has an effect. It is better not to use it because it will be erased.

When the transfer method uses a thermal head method or a hot stamping method, it is preferable that the foil has good cutting properties. For this reason, silica filler, colloidal silica, silicon filler, various waxes and the like may be added to the thermoplastic resin and the adhesive as necessary.
In this way, the first diffractive reflection layer 503 is formed so as to be aligned so that the diffraction pattern 506 matches the diffraction pattern 507 of the second diffractive reflection layer 505, and at first glance looks like FIG. Further, by superimposing the first retardation layer 102 thereon, the forgery prevention medium 50 with a diffraction structure can be formed. The appearance is as shown in FIG. 18, and the character pattern “Security” can be visually recognized as diffracted light. By overlapping the polarizing plate 10, a character pattern latent image of “TP” can be confirmed as shown in FIG.

FIG. 20 is a cross-sectional view of a transparent substrate on which a double-sided latent image forgery prevention medium 40 and a circularly polarized reflector 602 are provided.
A circularly polarized light reflector 602 is provided on one surface of the transparent substrate 601, and a double-sided latent image forgery prevention medium 40 is provided on the opposite surface, so that the double-sided latent image forgery prevention medium 40 and the circularly polarized light reflector 602 overlap each other. The mode that the transparent base material 601 is bent is shown. Although not shown in the drawing, an adhesive is provided between the double-sided latent image forgery prevention medium 40 or the circularly polarized reflector 602 and the transparent substrate 601.

  Two arrows indicate a state in which the reflected light from the circularly polarized reflector 602 is observed through the circularly polarizing filter 603, and the inverted reflected light 604, which is one of the arrows, is included in the double-sided latent image forgery prevention medium 40. The first retardation layer 102 and the third retardation layer 301 penetrate through the three-layer retardation area 306 having an angle of 0 degrees, and the other circularly polarized reflected light 605 is a circularly polarized light. The reflected light from the reflector 602 passes through the circular polarization filter 603 directly.

The transparent substrate 601 is desirably optically isotropic with no phase difference, such as triacetyl cellulose, polycarbonate, polypropylene, low density polyethylene, polyvinyl chloride, amorphous polyethylene terephthalate, nylon, polyetherimide, etc. An unstretched film using the material is desirable.
The circularly polarized light reflector 602 is formed by forming an oriented sheet of cholesteric liquid crystal on an appropriate sheet such as stretched polyethylene terephthalate or stretched polyethylene naphthalate, and transferring an absorbent layer formed thereon. May be provided by a printing method using ink in which a pigment that reflects circularly polarized light is dispersed, or a reflection layer formed on one side of a λ / 4 retardation film. You may provide by sticking so that the transparent base material 601 may be contact | connected.

The observation light of the inverted reflected light 604 and the circularly polarized reflected light 605 is transmitted through the circularly polarizing filter 603 on one side and shielded on the other side. The effect of the three-layer retardation area 306 is confirmed by verifying in this way. That is, with such a configuration, the presence or absence of reflected light from the circularly polarized reflector 602 can be confirmed.
Thus, each forgery prevention medium can be easily realized without requiring a large-scale facility. Moreover, since the pattern which becomes a latent image is formed by the 1st reflective layer 103 and the 2nd reflective layer 105, the pattern of a latent image can be formed easily and separately.

In order to obtain high adhesion when forming each layer of the anti-counterfeit medium described so far with reference to cross-sectional views and the like, an anchor layer and an adhesive layer are appropriately provided between the layers, although not shown. It's okay.
In the anti-counterfeit medium 30, the case where both the cholesteric layer and the black absorbing layer are provided has been described. However, it is not always necessary to provide the black absorbing layer, and the number of colors of reflected light obtained is reduced. There may be no color absorbing layer, or only a cholesteric layer may be provided.

  In addition, as a method for confirming the effect of the present invention, a visual method using the polarizing plate 10, the circularly polarized reflector 602, and the human eye has been exemplified, but a light receiving element such as a photodiode instead of the human eye, Machine reading may be performed using a CCD camera or the like by adding light sources such as various lamps and lasers. The function of individually forming latent images, which is a feature of the present invention, can form an image such as a barcode or a two-dimensional code on the premise of machine reading, and thus is compatible with machine reading.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the spirit of the present invention.
The anti-counterfeit medium 20, 30, 40, 50 may be used for a personal authentication such as an ID card. By using information such as an individual's face and name as a latent image, personal information cannot be recognized unless a polarizing plate is used even if an ID card is stolen by a malicious person, thus preventing leakage of personal information. In addition to the above, it may be possible to use the card to detect unauthorized use by assuming that it is a normal ID card with no personal information recorded.

For example, it can be applied to a sticker. In this case, an adhesive layer may be provided on the forgery prevention medium. By sticking these stickers to the article and observing the anti-counterfeit medium attached to the article, it is possible to determine the authenticity of the article as well as the ID card.
At this time, when an adhesive layer is provided on the surface opposite to the observation surface of the anti-counterfeit medium, it can be attached to various articles.

  On the other hand, when an adhesive layer is provided on the observation surface of the anti-counterfeit medium, the anti-counterfeiting effect can be confirmed through the article by using a transparent adhesive layer and sticking it on a transparent article. However, the transparent article needs to be an article having no phase difference, such as an acrylic plate or a glass plate produced without stretching. Further, also in the double-sided latent image forgery prevention medium 40, both sides of the double-sided latent image forgery prevention medium 40 can be used as an observation surface by using a transparent adhesive layer and sticking to a transparent article.

Examples of the present invention will be described below.
First, a stretched polyethylene naphthalate film having a thickness of 16 μm was coated with a wire bar using a cholesteric ink having the following composition so that the film thickness after drying and curing was 3 μm. After drying for a minute, a cholesteric layer was obtained by curing by irradiation with 500 mJ with a high-pressure mercury lamp.

<Cholesteric ink composition>
Nematic liquid crystal (Paliocolor LC242) (registered trademark) [manufactured by BASF] 30 parts by weight Chiral agent (Paliocolor LC756) (registered trademark) [manufactured by BASF] 1.5 parts by weight Polymerization initiator (Irgacure 184) [BASF Corp. Made] 1.5 parts by weight Solvent (methyl ethyl ketone) 67 parts by weight Subsequently, a cholesteric layer was coated with a wire bar using a sumi ink having the following composition, adjusted to a thickness of 3 μm after drying and curing. And dried at 100 ° C. for 3 minutes to obtain a black absorbing layer.

<Sumi ink composition>
NEWLP Super R92 Black [Toyo Ink Manufacture Co., Ltd.] 90 parts by weight NEWLP Super Curing Agent [Toyo Ink Manufacture Co., Ltd.] 10 parts by weight Subsequently, for the adhesive shown below, the film thickness after drying is 5 μm. What was adjusted so that it might become was apply | coated using the wire bar, and it dried at 80 degreeC for 2 minute (s), and obtained the contact bonding layer.

<Adhesive composition>
Polyolefin resin (Aurolen 100) (registered trademark) [Nippon Paper Chemical Co., Ltd.] 20 parts by weight Silica particles (Silo Hovic 505) [Fuji Silysia Co., Ltd.] 1 part by weight Solvent (toluene) 79 parts by weight The sheet was stacked so as to contact with a thick paper having a weight of about 100 grams, laminated with a silicone rubber roll having a temperature of 150 ° C. under an appropriate pressure, and the polyethylene naphthalate film was peeled off to obtain a color changing mount.
On the surface of the cholesteric layer of this color change mount, the anchor ink shown below was adjusted so that the film thickness after drying was 3 μm using a wire bar, dried at 100 ° C. for 2 minutes, and anchored. A layer was obtained.

<Anchor ink>
Vinyl chloride / vinyl acetate modified resin (Solvine A) (registered trademark) [manufactured by Nissin Chemical Industry Co., Ltd.] 30 parts by weight Silica particles (Silo Hovic 505) [manufactured by Fuji Silysia Ltd.] 1 part by weight Solvent (toluene) 34. 5 parts by weight Solvent (MEK) 34.5 parts by weight Subsequently, a second reflective layer is obtained by printing a square with a thermal head printer using a tipping ribbon (manufactured by Toppan Forms) at the center of the color change mount. It was.

Here, the second retardation obtained by applying and drying the previous adhesive on one side of the λ / 4 retardation film (Pure Ace WR-M: manufactured by Teijin Chemicals Ltd.) and the anchor ink on the opposite side under the same conditions. Prepare a film.
Laminate the surface of the color change mount so that the surface on which the second reflective layer is formed and the surface on which the adhesive of the λ / 4 retardation film is formed, and apply a suitable pressure to the silicone rubber roll at 150 ° C As a result, a second retardation layer was obtained.

Subsequently, a character pattern of “OK” is printed on the inner area of the second retardation layer on the inner side of the second reflective layer by using a printer with a thermal head using the dipping ribbon, and the first reflective layer is formed. Obtained.
Further, the above adhesive is coated and dried on one side of the λ / 4 retardation film under the same conditions, and the light scattering ink described below is dried on the opposite side so that the film thickness becomes 3 μm. A first retardation film obtained by coating and drying at 100 ° C. for 2 minutes was prepared.

<Light scattering ink>
Polyester resin (Byron 200) [Toyobo Co., Ltd.] 30 parts by weight Silica particles (Silo Hovic 100) [Fuji Silysia Co., Ltd.] 6 parts by weight Solvent (MEK) 64 parts by weight The surface of the first reflective layer of the color-change mount The first retardation film is in contact with the adhesive, and the first retardation film and the second retardation layer are stacked in such a direction that the orientation axis direction of the second retardation layer is at an angle of 45 degrees, and the silicon at a temperature of 150 ° C. The anti-counterfeit medium with a cholesteric structure obtained by laminating rubber rolls under moderate pressure is a mount that only shows a square silver area and a color change area around it. The latent image of the OK character pattern was confirmed, and the negative / positive reversal of the latent image and the light / dark of the color change area were switched by the rotation of the polarizing plate.

Further, when the anti-counterfeit medium was placed on a desk and observed through a polarizing plate from a little distance and the polarizing plate was rotated, only the color change area was switched between light and dark.
If a color change mount, tipping ribbon, first phase difference film, and second phase difference film are prepared in advance, only a printer with a thermal head and a laminator can be used to form a reflection area shape of a favorite shape and a latent image of a favorite pattern. can do.

10 ... Polarizing plate 20 ... Anti-counterfeit medium (basic structure)
30 ... Anti-counterfeit medium with cholesteric 40 ... Double-sided latent image anti-counterfeit medium 50 ... Anti-counterfeit medium with diffractive structure 100 ... Anti-counterfeit medium and polarizing plate in a state of being overlapped in the 0 degree direction ( A)
101 ... Polarizing plate in a state of being superimposed on a forgery prevention medium in the 0 degree direction (A)
102 ... first retardation layer 103 ... first reflective layer 104 ... second retardation layer 105 ... second reflective layer 106 ... cholesteric layer and black absorbing layer 107 ... 0 degree The optical axis direction 108 of the polarizing plate (A) in a state of being superimposed on the anti-counterfeit medium in the direction ... the orientation axis direction 109 of the first retardation layer ... the orientation axis direction 110 of the second retardation layer ..Natural light 111: Linearly polarized light (A) that has passed through polarizing plate (A) in a state where natural light is superimposed on the anti-counterfeit medium in the 0 degree direction
112... Circularly polarized light (A) in which linearly polarized light (A) has passed through the first retardation layer
113 ... Circularly polarized light (B) in which circularly polarized light (A) is reflected by the first reflective layer
114... Linearly polarized light (B) in which circularly polarized light (B) has passed through the first retardation layer
115: Observation light (A) in which linearly polarized light (B) passes through polarizing plate (A)
116: Linearly polarized light (Cα) in which circularly polarized light (A) passes through the second retardation layer
117: Linearly polarized light (Cβ) reflected from the second reflective layer by linearly polarized light (C1)
118: Circularly polarized light (C) in which linearly polarized light (C2) has passed through the second retardation layer
119: Linearly polarized light (D) in which circularly polarized light (C) passes through the first retardation layer
120: Observation light (B) in which linearly polarized light (D) passes through polarizing plate (A)
121: Linearly polarized light (Cγ) reflected from the second reflective layer by linearly polarized light (C1)
122... Circularly polarized light reflected from the cholesteric layer (D)
123... Linearly polarized light (E) in which circularly polarized light (D) passes through the second retardation layer
124: Linearly polarized light (E) in which linearly polarized light (E) passes through the first retardation layer
125 ... Observation light (C) in which linearly polarized light (F) passes through polarizing plate (A)
200: Polarizing plate (B) in a state of being overlapped with an anti-counterfeit medium in a 45-degree direction
201... Polarizing plate (B) overlaid on anti-counterfeit medium in 45 ° direction
207: Transmission optical axis direction 211 of the polarizing plate (B) in a state of being superimposed on the anti-counterfeit medium in the 45 degree direction. Linearly polarized light passing through (B) (G)
212 ... Linearly polarized light (G) in which linearly polarized light (G) has passed through the first retardation layer
213: Linearly polarized light (I) reflected from the first reflective layer by linearly polarized light (H)
214: Linearly polarized light (J) in which linearly polarized light (I) passes through the first retardation layer
215: Observation light (D) in which linearly polarized light (J) passes through polarizing plate (B)
216: Circularly polarized light (Eα) in which linearly polarized light (H) passes through the second retardation layer
217 ... Circularly polarized light (F) in which circularly polarized light (E) is reflected by the second reflective layer
218: Linearly polarized light (K) in which circularly polarized light (F) has passed through the second retardation layer
219: Linearly polarized light (L) in which linearly polarized light (K) passes through the first retardation layer
220: Observation light (E) in which linearly polarized light (L) passes through polarizing plate (B)
221: Circularly polarized light (Eβ) in which linearly polarized light (H) passes through the second retardation layer
222 ... Circularly polarized light reflected from the cholesteric layer (F)
223... Linearly polarized light (M) in which circularly polarized light (F) has passed through the second retardation layer
224: Linearly polarized light (N) in which linearly polarized light (M) passes through the first retardation layer
225 ... Observation light (F) in which linearly polarized light (N) passes through polarizing plate (B)
301 ... 3rd phase difference layer 302 ... A surface 1 layer retardation area 303 ... A surface 2 layer retardation area 304 ... B surface 1 layer retardation area 305 ... B surface 2 layer Phase difference area 306... Three-layer phase difference area 307... Third phase difference layer (α) in which the angle formed with the orientation axis direction of the first phase difference layer is 0 degree.
308: Third retardation layer (β) having an angle of 90 degrees with the orientation axis direction of the first retardation layer
309 ... orientation axis direction 310 of the third retardation layer (α) ... orientation axis direction 311 of the third retardation layer (β) ... cholesteric layer and black absorbing layer 312 that reflect right circularly polarized light ..Right circularly polarized light 313 reflected by the surface of the cholesteric layer ... Linearly polarized light (O) in which the right circularly polarized light has passed through the first retardation layer
314: Linearly polarized light (P) in which linearly polarized light (O) passes through the second retardation layer
315: Circularly polarized light (G) in which linearly polarized light (P) passes through the third retardation layer (α)
316: Circularly polarized light (H) in which linearly polarized light (P) has passed through the third retardation layer (β)
317: a cholesteric layer that reflects left circularly polarized light and a black absorbing layer 318: left circularly polarized light 319 reflected by the surface of the cholesteric layer: linearly polarized light (Q) in which the left circularly polarized light passes through the first retardation layer
320: Linearly polarized light (R) in which linearly polarized light (Q) passes through the second retardation layer
321... Circularly polarized light (I) in which linearly polarized light (R) has passed through the third retardation layer (α)
322: Circularly polarized light (J) in which linearly polarized light (R) passes through the third retardation layer (β)
503... First diffraction reflection layer 505... Second diffraction reflection layer 506... Diffraction pattern 507... Removal part 601. Transparent substrate 602. Polarizing filter 604... Inverted reflected light 605... Circularly polarized reflected light

Claims (8)

A forgery prevention medium in which a first retardation layer, a first reflection layer, a second retardation layer, and a second reflection layer are laminated in this order,
The first retardation layer and the second retardation layer are provided over the entire surface direction, and both of the retardation values of the first retardation layer and the second retardation layer are λ / 4. An anti-counterfeit medium, wherein an angle formed by the orientation axes of one retardation layer and the second retardation layer is 45 degrees. A forgery prevention medium in which a first retardation layer, a first reflection layer, a second retardation layer, a second reflection layer, and a color change layer are laminated in this order,
The first retardation layer and the second retardation layer are provided over the entire surface direction, and both of the retardation values of the first retardation layer and the second retardation layer are λ / 4. An anti-counterfeit medium, wherein an angle formed by the orientation axes of one retardation layer and the second retardation layer is 45 degrees. A forgery prevention medium in which a first retardation layer, a first reflection layer, a second retardation layer, a second reflection layer, and a third retardation layer are laminated in this order,
The first retardation layer, the second retardation layer, and the third retardation layer are respectively provided on the entire surface direction, and the first retardation layer, the second retardation layer, and the third retardation layer are provided. The phase difference value of each is λ / 4,
Further, the angle formed between the alignment axes of the first retardation layer and the second retardation layer and the angle formed between the alignment axes of the second retardation layer and the third retardation layer are 45 degrees, respectively. An anti-counterfeit medium, wherein an angle formed between the orientation axes of the first retardation layer and the third retardation layer is 0 degree. A forgery prevention medium in which a first retardation layer, a first reflection layer, a second retardation layer, a second reflection layer, and a third retardation layer are laminated in this order,
The first retardation layer, the second retardation layer, and the third retardation layer are respectively provided on the entire surface direction, and the first retardation layer, the second retardation layer, and the third retardation layer are provided. The phase difference value of each is λ / 4,
Further, the angle formed between the alignment axes of the first retardation layer and the second retardation layer and the angle formed between the alignment axes of the second retardation layer and the third retardation layer are 45 degrees, respectively. An anti-counterfeit medium, wherein an angle formed between the orientation axes of the first retardation layer and the third retardation layer is 90 degrees.   The forgery prevention medium according to claim 2, wherein the color change layer includes a cholesteric liquid crystal.   Each of the first reflective layer and the second reflective layer has a diffractive structure, and the first reflective layer and the second reflective layer are provided so that the positions of the diffractive structures of the reflective layers overlap each other. The forgery prevention medium according to any one of claims 1 to 5, wherein   An anti-counterfeit sticker, wherein an adhesive layer is provided on a surface opposite to the observation surface of the anti-counterfeit medium according to any one of claims 1 to 6.   An anti-counterfeit article comprising the anti-counterfeit medium according to any one of claims 1 to 6.

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