JP5028642B2 - Laminated body, adhesive label, recording medium, labeled article and discrimination method - Google Patents

Description

  The present invention relates to a discrimination technique for discriminating an article between a genuine product and a non-genuine product.

  It is desired that counterfeiting is difficult for authentication media such as cash cards, credit cards and passports, and securities media such as gift certificates and stock certificates. Therefore, conventionally, a label that is difficult to forge is attached to such a medium in order to prevent the forgery.

  In recent years, the distribution of counterfeit products has been regarded as a problem for articles other than authentication media and securities media. Therefore, the opportunity to apply the above-described anti-counterfeiting technology for authentication media and securities media to such articles is increasing.

The forgery prevention technology can be classified into an overt technology and a covert technology.
The overt technique is an anti-counterfeiting technique that allows a general user to easily recognize application to an article and easily determine whether it is authentic. In a typical overt technique, a diffractive structure such as a hologram or a multilayer interference film such as Optically Variable Ink (OVI) is used.

  The covert technique is an anti-counterfeiting technique aimed at making it possible for only a specific user who knows the application of the covert technique to an article to make an authenticity determination because it is difficult for a general user to apply to the article. Typical covert techniques use fluorescent printing or line moire.

  Patent Documents 1 and 2 describe other covert techniques. In this covert technique, for example, a label including a reflective layer and a birefringent layer covering a part thereof is used. When the label is irradiated with natural light, the optical anisotropic region corresponding to the portion of the reflective layer covered with the birefringent layer and the optical portion corresponding to the portion not covered with the birefringent layer, etc. It is difficult to distinguish the isotropic region. When a polarizing film is placed on the label, the optically anisotropic region is compared to the optically isotropic region when the transmission axis of the polarizing film is oblique to the optical axis of the birefringent layer. Looks darker. Using the visible image formed by the bright part and the dark part, the authenticity of the article to which this label is attached is confirmed.

As described above, in the covert technique described in Patent Documents 1 and 2, a latent image is formed using a birefringent layer. However, in order to visualize this latent image, it is necessary to transmit the light from the light source to the polarizing layer and then irradiate the label, and transmit the light reflected by the label to the polarizing layer. Therefore, in order to perform authenticity determination, the polarizing layer must be positioned in the vicinity of the label. In addition, higher visibility is desired for the visualized latent image. In other words, this technique has room for improvement in terms of the visibility of the visualized latent image and the ease of authenticity determination.
JP 2001-39100 A JP-A-9-68926

  An object of the present invention is to provide a technique capable of forming a latent image having excellent visibility when visualized and more easily discriminating between genuine products and non-authentic products.

According to a first aspect of the present invention, it viewed including the first and second portions aligned in plane direction, scattering the size of the light scattering changes when rotating the polarization plane of the linearly polarized light as the incident light A polarizing layer, a birefringent layer positioned on the front side of the polarizing layer and facing only at the position of the polarizing layer and the first portion, and a light absorbing layer or reflecting layer facing the back surface of the polarizing layer The identification laminated body characterized by having comprised is provided.

  According to the 2nd side surface of this invention, the adhesive label characterized by having comprised the laminated body which concerns on a 1st side surface, and the adhesion layer supported by the back surface of the said laminated body is provided.

  According to a third aspect of the present invention, there is provided a paper, a pressure-sensitive adhesive layer supported on one main surface of the paper, and a lamination according to the first side surface embedded in the paper so that a back surface faces the pressure-sensitive adhesive layer. An adhesive label characterized by comprising a body is provided.

  According to a fourth aspect of the present invention, there is provided a recording medium comprising paper and the laminate according to any one of claims 1 to 3 embedded in the paper. .

  According to a fifth aspect of the present invention, there is provided a label comprising: an article whose authenticity is to be confirmed; and a laminate according to the first side surface supported by the article whose authenticity is to be confirmed. Articles are provided.

  According to a sixth aspect of the present invention, there is provided a method for discriminating an article whose authenticity is unknown between a genuine article and a non-authentic article, wherein the authentic article is a labeled article according to the fifth aspect, If the unknown article does not include a light-scattering region that holds a latent image that is visualized by observing through a polarizer, it is determined that the unknown authentic article is non-authentic. A method is provided that includes:

  According to a seventh aspect of the present invention, there is provided a method for discriminating an article whose authenticity is unknown between an authentic product and a non-authentic product, the authentic product including an article whose authenticity is to be confirmed, and the authentic product. And a laminate according to the first side surface supported by the article to be confirmed, the laminate further comprising a reflective layer facing the back surface of the polarizing layer, and the authenticity If an unknown article is visualized by observing through a polarizer and does not hold a latent image in which the positions of the bright part and the dark part are switched by changing the observation angle in the visualized state, the authenticity A method is provided that includes determining that the unknown item is non-genuine.

  According to the present invention, it is possible to form a latent image having excellent visibility when visualized, and to more easily discriminate between genuine products and non-authentic products.

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

  FIG. 1 is a plan view schematically showing a layered product for identification according to one embodiment of the present invention. 2 is a cross-sectional view taken along the line II-II of the laminate shown in FIG. 3 and 4 are perspective views schematically showing the scattering-type polarizing layer included in the laminate of FIG.

  As shown in FIG. 2, the identification laminate 10 includes a scattering polarizing layer 11, a birefringent layer 12, a light absorption / reflection layer 13, and an overcoat layer 14.

  Here, the term “polarizing layer” means a layer functioning as a linear polarizer unless otherwise specified. The term “polarizer” includes “linear polarizer”, “elliptical polarizer”, and “circular polarizer”, and does not include the concept of shape.

The scattering-type polarizing layer 11 is a layer in which the magnitude of light scattering changes when the plane of polarization of linearly polarized light (vibration plane of the electric field vector) as incident light is rotated. As shown in FIG. 3, when the transmission axis _AT of the scattering polarizing layer 11 and the polarization plane of the linearly polarized light L _LP as incident light are parallel, the scattering polarizing layer 11 is ideally linearly polarized. Transmits L _LP without scattering. When the angle formed by the polarization plane of the linearly polarized light L _LP with respect to the transmission axis _AT is increased, the light component scattered by the scattering-type polarizing layer 11 increases. As shown in FIG. 4, when the polarization plane of the linearly polarized light L _LP and the transmission axis _AT are orthogonal, the scattering type polarization layer 11 scatters the most light component.

  Various structures can be adopted for the scattering-type polarizing layer 11 as described below.

  For example, the scattering-type polarizing layer 11 may include a birefringent first layer having an uneven surface as a scattering surface, and a second layer in contact with the uneven surface. For example, when the first layer is a uniaxial crystal having an optical axis substantially parallel to the in-plane direction and the second layer is optically isotropic, the refractive index of the second layer is the ordinary ray refraction of the first layer. If the rate is substantially equal, the scattering-type polarizing layer 11 transmits ordinary light with almost no scattering, and scatters extraordinary light.

  A birefringent material such as calcite can be used as the material for the first layer. As the material of the second layer, for example, a resin such as polymethyl methacrylate can be used.

  When the above structure is adopted for the scattering-type polarizing layer 11, the second layer may be optically anisotropic. For example, when the second layer is a uniaxial crystal, the first layer and the second layer are arranged so that their optical axes are parallel. Then, the ordinary light refractive indexes of the first layer and the second layer are made substantially the same, and the extraordinary light refractive indexes of the first layer and the second layer are made different. The scattering-type polarizing layer 11 employing this structure transmits ordinary light with little scattering, and scatters extraordinary light.

  The scattering polarizing layer 11 may have a multilayer structure including three or more layers. For example, the scattering polarizing layer 11 may have a structure in which a birefringent first layer whose both surfaces are uneven surfaces is sandwiched between a pair of second layers.

  The scattering-type polarizing layer 11 may have a structure in which transparent particles are dispersed in a transparent matrix. For example, when the transparent matrix is a uniaxial crystal and the transparent particles are optically isotropic, if the refractive index of the transparent particles is approximately equal to the ordinary ray refractive index of the transparent matrix, the scattering type polarizing layer 11 is an ordinary ray. Is transmitted with almost no scattering, and extraordinary rays are scattered.

  As the transparent matrix, for example, a uniaxially stretched polymer layer can be used. As the material of the polymer layer, for example, polyethylene, polyethylene terephthalate, polyethylene naphthalate, polypropylene, polycarbonate, polystyrene, polyvinyl chloride, polyvinyl alcohol, and a mixture containing one or more thereof can be used. As a material for the transparent particles, for example, an organic substance such as a crosslinked polystyrene, a divinylbenzene crosslinked product, or a methyl methacrylate crosslinked product can be used. Alternatively, inorganic materials such as silica and alumina may be used as the material for the transparent particles.

  When the above structure is adopted for the scattering polarizing layer 11, the transparent particles may be optically anisotropic. For example, uniaxial crystals are used as the transparent particles, and the optical axes of the transparent particles are substantially parallel to each other. In this case, as a material for the transparent particles, for example, a liquid crystal material exhibiting a nematic phase or a smectic phase in the operating temperature range of the laminate 10, typically a polymer liquid crystal material can be used. The optical axes of the transparent particles can be made substantially parallel to each other, for example, by stretching the scattering polarizing layer 11. Further, when the transparent particles are optically anisotropic, the transparent matrix may be optically isotropic.

  The birefringent layer 12 faces a part of the front surface of the scattering-type polarizing layer 11. The scattering polarizing layer 11 and the birefringent layer 12 are in contact with each other in this example, but they are not necessarily in contact with each other. Any layer may be interposed between the two. For example, an easy-adhesion layer or an alignment film for liquid crystal may be interposed between the scattering-type polarizing layer 11 and the birefringent layer 12 to increase their adhesion.

  The birefringent layer 12 has substantially uniform optical characteristics in the plane. The optical axis of the birefringent layer 12 is substantially parallel to the main surface of the scattering polarizing layer 11 and is oblique to the transmission axis of the scattering polarizing layer 11. For example, the birefringent layer 12 and the scattering-type polarizing layer 11 are arranged so that the optical axis of the birefringent layer 12 forms an angle of about 45 ° with respect to the transmission axis of the scattering-type polarizing layer 11.

  The area AA1 corresponding to the birefringent layer 12 in the front surface of the laminate 10 forms a latent image that is difficult to distinguish from the adjacent area AA2. That is, when the front surface of the laminate 10 is directly observed without using a polarizer, it is difficult to find the difference between the area AA1 and the area AA2. When the front surface of the laminated body 10 is observed through the polarizer, a difference in brightness occurs between the area AA1 and the area AA2. Thereby, the latent image is visualized.

  The birefringent layer 12 may be in direct contact with the front surface of the scattering-type polarizing layer 11. Alternatively, an optically isotropic transparent layer may be interposed between the birefringent layer 12 and the scattering-type polarizing layer 11.

  As the birefringent layer 12, for example, a birefringent stretched film can be used. As this stretched film, for example, a uniaxially or biaxially stretched polyolefin film and polyester film can be used. When a part of the birefringent stretched film is optically isotropic, that part is excluded from the birefringent layer 12.

  A liquid crystal material may be used as the material of the birefringent layer 12. As this liquid crystal material, for example, a liquid crystal material that is solid in the use temperature range of the laminate 10 and exhibits a nematic phase or a smectic phase, typically a polymer liquid crystal material, can be used. In this case, for example, by forming a thin film pattern made of a liquid crystal material and applying heat and pressure to the thin film pattern, the alignment of the liquid crystal can be made uniform. Alternatively, a birefringent layer 12 in which the alignment of the liquid crystal is aligned can be obtained by forming a thin film pattern made of a low molecular weight liquid crystal material on the alignment film and causing polymerization of the liquid crystal material. The alignment film is obtained, for example, by forming a resin layer such as polyimide and performing an alignment treatment such as rubbing on the resin layer.

  The light absorption / reflection layer 13 is a light absorption layer or a reflection layer. The light absorption / reflection layer 13 faces the back surface of the scattering-type polarizing layer 11. The light absorption / reflection layer 13 may face the entire back surface of the scattering-type polarizing layer 11 or may face only a part thereof. Further, the light absorption / reflection layer 13 may be omitted.

  The light absorption / reflection layer 13 may be in direct contact with the back surface of the scattering polarizing layer 11. Alternatively, a transparent layer may be interposed between the light absorption / reflection layer 13 and the scattering polarizing layer 11.

  When the light absorption / reflection layer 13 is a light absorption layer, this light absorption layer can be obtained, for example, by applying an ink containing a pigment and / or a dye and a resin to the back surface of the scattering polarizing layer 11. Or this light absorption layer is obtained by apply | coating the previous ink on a base material. In this case, the light absorption layer can be attached to the back surface of the scattering-type polarizing layer 11 together with the base material.

  The light absorbing layer may be black or another color. The light absorption layer may include a plurality of portions having different colors and arranged in the in-plane direction.

  When the light absorption layer is black, when the latent image is not visualized, the colors of the regions AA1 and AA2 are white due to the light scattering of the scattering polarizing layer 11. When the latent image is visualized, one of the areas AA1 and AA2 changes to black. If the light absorption layer is black, the contrast ratio of these regions is maximized when the latent image is visualized.

  When a light absorbing layer that absorbs only a part of visible light and reflects another part is used, when the latent image is not visualized, the colors of the regions AA1 and AA2 are the light scattering of the scattering-type polarizing layer 11. This is a color generated by mixing the white color caused by the color and the color caused by the reflection of the light absorption layer. When the latent image is visualized, one of the areas AA1 and AA2 has a weak color due to the reflection of the light absorption layer, and the other has a change to a color due to the reflection of the light absorption layer.

  When the light absorption / reflection layer 13 is a reflection layer, this reflection layer is obtained by depositing a metal or an alloy on the back surface of the scattering-type polarizing layer 11 by, for example, vacuum evaporation or sputtering. Alternatively, the reflective layer can be obtained by depositing a metal or alloy on the substrate by the same method as described above. In this case, the reflective layer can be attached to the back surface of the scattering-type polarizing layer 11 together with the base material.

  When the light absorption / reflection layer 13 is a reflection layer, when the latent image is not visualized, the colors of the regions AA1 and AA2 are white due to the light scattering of the scattering type polarizing layer 11, or the scattering type. It is white due to light scattering of the polarizing layer 11 and reflection of the reflecting layer. When the latent image is visualized, a difference in luminance is generated between the areas AA1 and AA2.

  The overcoat layer 14 covers the front surface of the scattering-type polarizing layer 11 and the birefringent layer 12. The overcoat layer 14 is an optically isotropic transparent layer, typically a transparent resin layer. The overcoat layer 14 flattens the uneven surface formed by the scattering-type polarizing layer 11 and the birefringent layer 12. This obfuscates the presence of the birefringent layer 12. The overcoat layer 14 may be omitted.

  The overcoat layer 14 is obtained, for example, by applying a transparent printing ink to the scattering-type polarizing layer 11 and the birefringent layer 12. For the application of the printing ink, for example, a coating method such as gravure and microgravure can be used.

Next, the visualization of the latent image will be described.
5 and 6 are diagrams schematically illustrating an example of a method for visualizing the latent image held by the stacked body illustrated in FIG. 1. FIG. 5 illustrates a state in which the area AA1 reflects light. FIG. 6 illustrates a state where the area AA2 reflects light.

  The laminated body 10 shown in FIGS. 5 and 6 includes a reflection layer as the light absorption / reflection layer 13 and includes a half-wave plate as the birefringent layer 12. The angle formed by the transmission axis of the scattering-type polarizing layer 11 and the optical axis of the birefringent layer 12 is 45 °.

  In the method shown in FIGS. 5 and 6, the front surface of the laminate 10 is observed through the verification tool 200 while irradiating the front surface of the laminate 10 with natural light. Here, as an example, an absorptive polarizing layer such as a polarizing layer in which a stretched polyvinyl alcohol layer is impregnated with iodine is used as the verification tool 200. Further, in this method, the laminated body 10, the light source 300, and the observer 400 are arranged so that the observer 400 can observe the reflected light when the laminated body 10 specularly reflects light from the light source 300.

As shown in FIG. 5, the natural light L _N from the light source 300 is incident on the birefringent layer 12 in the portion corresponding to the region AA1. The birefringent layer 12 transmits this natural light _LN .

Natural light L _N emitted from the birefringent layer 12 is incident on the scattering polarizing layer 11. Scattering type polarizing layer 11, of the natural light L _N, the plane of polarization parallel to the linearly polarized light transmission axis A _T (or less, S of polarized light) passes through without substantially scattering L _PS. Of the natural light L _N , linearly polarized light (hereinafter referred to as P-polarized light) L _PP whose polarization plane is perpendicular to the transmission axis _AT will be described later.

The S-polarized light L _PS emitted from the scattering-type polarizing layer 11 is reflected by the light absorption / reflection layer 13 and enters the scattering-type polarizing layer 11 again. The scattering-type polarizing layer 11 transmits this S-polarized light _LPS with almost no scattering.

S-polarized light L _PS with a scattering type polarizing layer 11 emitted is incident on the birefringent layer 12. The birefringent layer 12 converts S-polarized light _LPS into P-polarized light _LPP .

The P-polarized light L _PP emitted from the birefringent layer 12 enters the verification tool 200. If the transmission axis A _T validation tool 200 as shown in FIG. 4 'transmission axis A _T of the scattering type polarizing layer 11' is parallel to, the verification device 200 absorbs the P polarized light L _PP. Therefore, the light component (hereinafter referred to as non-scattered light) transmitted without scattering by the scattering-type polarizing layer 11 does not reach the observer 400.

The scattering-type polarizing layer 11 scatters the P-polarized light L _PP forward and backward from the natural light L _N from the light source 300 transmitted through the birefringent layer 12. Here, for simplification, it is assumed that the scattering-type polarizing layer 11 scatters the P-polarized light L _PP without converting it into partially polarized light.

The P-polarized light L _PP backscattered by the scattering-type polarizing layer 11 is incident on the birefringent layer 12 again. On the other hand, the P-polarized light L _PP scattered forward by the scattering-type polarizing layer 11 is reflected by the light absorption / reflection layer 13 and enters the scattering-type polarizing layer 11 again. The scattering type polarization layer 11 scatters P-polarized light L _PP forward and backward. In this way, the P-polarized light L _PP having a low directivity is incident on the birefringent layer 12. The birefringent layer 12 converts P-polarized light L _PP into S-polarized light L _PS .

The S-polarized light L _PS emitted from the birefringent layer 12 enters the verification tool 200. The verification tool 200 transmits the S-polarized light _LPS . However, since this S-polarized light _LPS is scattered light, only a part of the light components reach the observer 400 and the remaining light components do not reach the observer 400.

In the portion corresponding to the area AA2, the natural light L _N from the light source 300 is incident on the scattering type polarization layer 11, as shown in FIG. Scattering type polarizing layer 11, of the natural light L _N, transmitted almost without scattering the S-polarized light L _PS. Of the natural light L _N , the P-polarized light L _PP will be described later.

The S-polarized light L _PS emitted from the scattering-type polarizing layer 11 is reflected by the light absorption / reflection layer 13 and enters the scattering-type polarizing layer 11 again. The scattering-type polarizing layer 11 transmits this S-polarized light _LPS with almost no scattering.

The S-polarized light L _PS emitted from the scattering-type polarizing layer 11 enters the verification tool 200. Absorptive polarizing layer 200 is transmitted through the S-polarized light L _PS. Therefore, the light component transmitted without scattering by the scattering-type polarizing layer 11 reaches the observer 400.

The scattering-type polarizing layer 11 scatters the P-polarized light L _PP forward and backward from the natural light L _N from the light source 300. The P-polarized light L _PP backscattered by the scattering-type polarizing layer 11 enters the verification tool 200 again. On the other hand, the P-polarized light L _PP scattered forward by the scattering-type polarizing layer 11 is reflected by the light absorption / reflection layer 13 and enters the scattering-type polarizing layer 11 again. The scattering type polarization layer 11 scatters P-polarized light L _PP forward and backward. In this way, the P-polarized light L _PP as the scattered light is incident on the verification tool 200. Since the verification device 200 absorbs P polarized light L _PP, the P-polarized light L _PP does not reach the observer 400.

  Thus, the area AA1 emits only low-intensity scattered light toward the observer 400 without emitting high-intensity non-scattered light. On the other hand, the area AA2 emits high-intensity non-scattered light toward the observer 400 and does not emit low-intensity scattered light. Therefore, the viewer 400 perceives the areas AA1 and AA2 as dark parts and bright parts, respectively. As described above, the latent image can be visualized.

  In the method described with reference to FIGS. 5 and 6, the laminated body 10, the light source 300, and the observer 400 observe the reflected light when the laminated body 10 specularly reflects the light from the light source 300. Arranged as possible. When only the observation angle is changed in this state, the positions of the bright part and the dark part are switched. That is, the area AA1 changes from a dark part to a bright part, and the area AA2 changes from a bright part to a dark part. This will be described below.

  If only the observation angle is sufficiently changed from the state described with reference to FIGS. 5 and 6, the high-intensity non-scattered light emitted from the area AA <b> 2 cannot reach the observer 400. Since the area AA2 does not emit low-intensity scattered light, the brightness of the area AA2 becomes almost zero.

  On the other hand, the area AA1 does not emit high-intensity non-scattered light, and emits only low-intensity scattered light. For this reason, in the area AA1, there is almost no change in luminance associated with changing the observation angle.

  Therefore, in this case, the viewer 400 perceives the areas AA1 and AA2 as a bright part and a dark part, respectively. For this reason, when the observation angle is changed, the positions of the bright part and the dark part are switched.

Even when the angle formed by the transmission axis A _T ′ of the verification tool 200 with respect to the transmission axis A _T of the scattering-type polarizing layer 11 is changed, the positions of the bright part and the dark part are switched. For example, when the transmission axis A _T ′ is perpendicular to the transmission axis A _T , the positions of the bright part and the dark part are opposite to those described with reference to FIGS.

Further, when a light absorption layer is used as the light absorption / reflection layer 13 instead of the reflection layer, none of the areas AA1 and AA2 emits high intensity non-scattered light. Therefore, when the parallel transmission axes A _T validation tool 200 'to the transmission axis A _T of the scattering type polarizing layer 11, the viewer 400 perceives the regions AA1 and AA2 as a light portion and a dark portion, respectively. Then, when the vertical transmission axes A _T validation tool 200 'to the transmission axis A _T of the scattering type polarizing layer 11, the viewer 400 perceives the regions AA1 and AA2 respectively as a dark portion and a bright portion.

  As described above, the light applied to the stacked body 10 for visualizing the latent image need not be linearly polarized light. Therefore, it is not necessary to position the verification tool 200 in the vicinity of the stacked body 10. Therefore, this technique makes it easier to visualize the latent image as compared with the case where the laminated body 10 must be irradiated with linearly polarized light in order to visualize the latent image.

  Further, in this method, since the latent image is visualized using scattered light, the range of observation angles at which the visualized latent image can be visually recognized is wide. That is, when the structure described with reference to FIGS. 1 and 2 is employed, a latent image having excellent visibility can be formed when visualized.

  In the method described with reference to FIGS. 5 and 6, natural light is used as light applied to the stacked body 10 in order to visualize the latent image, but linearly polarized light may be used instead. For example, the verification tool 200 may be positioned in the vicinity of the stacked body 10, and the stacked body 10 may be irradiated with linearly polarized light transmitted by the verification tool 200.

  In the method described with reference to FIGS. 5 and 6, the polarizing layer is used as the verification tool 200, but the verification tool 200 may not be a layer. For example, a polarizing prism may be used.

  Moreover, although the verification tool 200 used by the method demonstrated with reference to FIG.5 and FIG.6 is a linear polarizer, you may use an elliptical polarizer or a circular polarizer instead. For example, when a quarter wave plate is used as the birefringent layer 12 instead of the half wave plate, a circular polarizer can be used.

  In the above description, the polarizer is used as the verification tool 200 for visualizing the latent image. However, the latent image can be visualized without using the polarizer. This will be described below.

  FIG. 7 is a diagram schematically illustrating another example of a method for visualizing the latent image held by the stacked body illustrated in FIG. 1.

In this method, a transparent body 200 ′ such as a transparent plate is used as a verification tool. Specifically, the natural light L _N emitted from the light source 300 is irradiated onto the laminated body 10, and the light reflected by the laminated body 10 is incident on the transparent body 200 ′. Here, as an example, the reflected light from the area AA1 is linearly polarized light (hereinafter referred to as S wave) L _S whose polarization plane is perpendicular to the main surface of the transparent body 200 ′, and the reflected light from the area AA2 is polarized light. It is assumed that the plane is linearly polarized light (hereinafter referred to as P wave) L _P perpendicular to the plane of polarization of the S wave L _S.

The incident angle θ of the S wave L _S and the P wave L _P with respect to the transparent body 200 ′ is made substantially equal to the Brewster angle. For example, when a glass plate having a refractive index of about 1.5 is used as the transparent body 200 ′, the incident angle is set to about 56 °.

In this way, most of the light reflected by the transparent body 200 ′ becomes the S wave L _S. That is, the reflected light from the area AA1 among the reflected light from the stacked body 10 reaches the observer 400, but the reflected light from the area AA2 hardly reaches. Therefore, the viewer 400 perceives the areas AA1 and AA2 as a bright part and a dark part, respectively. As described above, the latent image can be visualized.

  In the arrangement shown in FIG. 7, when the laminated body 10 is rotated by 90 ° around the normal line, the regions AA1 and AA2 appear as dark portions and bright portions, respectively. Similarly to the case described with reference to FIGS. 5 and 6, when only the observation angle is changed from the state shown in FIG. 7, the positions of the bright part and the dark part are switched.

  A light absorption layer can be provided on the back side of the transparent body 200 ′. Employing this configuration improves the contrast ratio of the visible image.

  The transparent body 200 'is typically a transparent plate, but may not be a transparent plate as long as it has a smooth surface. The transparent body 200 ′ may be used only for the visualization, or may be used for other purposes such as a display cover plate mounted on a portable device. Good.

  Since the laminate 10 described above includes the scattering-type polarizing layer 11, when the front surface of the laminate 10 is directly observed without using the verification tool 200, the front surface of the laminate 10 does not depend on the observation angle. Looks bright. Therefore, a highly visible print pattern can be formed on the front surface of the laminate 10.

  FIG. 8 is a plan view schematically showing a modification of the laminate shown in FIG. FIG. 9 is a cross-sectional view taken along line IX-IX of the stacked body shown in FIG.

  The laminate 10 shown in FIGS. 8 and 9 is the same as the laminate 10 described with reference to FIGS. 1 and 2 except that the laminate 10 further includes a printed pattern 15 formed on the overcoat layer 14. It has a structure. Thus, the printing pattern 15 can be formed on the overcoat layer 14.

  The print pattern 15 may be interposed between the overcoat layer 14 and the birefringent layer 12. Alternatively, the print pattern 15 may be interposed between the overcoat layer 14 and the scattering-type polarizing layer 11. Alternatively, the print pattern 15 may be interposed between the birefringent layer 12 and the scattering-type polarizing layer 11.

  The laminate 10 described above is supported directly or indirectly on an article whose authenticity is to be confirmed. And when discriminating an article whose authenticity is unknown between a genuine product and a non-authentic product such as a counterfeit product, the laminate 10 can be used as described below.

  As described above, the stacked body 10 includes the scattering-type polarizing layer 11. Therefore, the article on which the laminate 10 is supported has a light scattering region. Therefore, when an article whose authenticity is unknown does not have a light scattering region, it can be determined that the article is non-authentic.

  The laminate 10 has a latent image that is visualized by observing through a polarizer. That is, at least a partial region of the article supporting the laminated body 10 has a latent image that is visualized by observing through the polarizer. Therefore, if an article with unknown authenticity does not have such a latent image, it can be determined that the article is non-authentic.

  The latent image is formed on the scattering polarizing layer 11. Therefore, even if an article of unknown authenticity includes a light scattering area and an area having a latent image, it is determined that the article is non-authentic if the areas are not identical. can do.

  If an article of unknown authenticity holds the previous latent image, the shape and / or size of the visualized latent image may be compared with that of the authentic product. If the shape and / or size of the visualized latent image is different from that of the genuine product, it can be determined that the article is non-genuine.

  When the light absorption / reflection layer 13 is a reflection layer, the following method can also be used. As described above, when the light absorption / reflection layer 13 is a reflection layer, the positions of the bright part and the dark part are switched by changing the observation angle. Therefore, an article that does not have a latent image that causes such a change can be determined to be non-genuine.

  When a light absorption layer that absorbs only a part of visible light and reflects another part is used as the light absorption / reflection layer 13, as described above, when the latent image is not visualized, the regions AA1 and AA2 The color is a color generated by mixing the white color resulting from the light scattering of the scattering-type polarizing layer 11 and the color resulting from the reflection of the light absorption layer. When the latent image is visualized, one of the areas AA1 and AA2 has a weak color due to the reflection of the light absorption layer, and the other has a change to a color due to the reflection of the light absorption layer. Thus, if an article of unknown authenticity retains the previous latent image, the unvisualized latent image and / or the color of the visualized latent image may be compared to that of the authentic product. If the latent image that has not been visualized and / or the color of the visualized latent image is different from that of the genuine product, the article can be determined to be non-genuine.

  For the determination of an article, only one of the above-described methods may be used, or a plurality of methods may be used in combination. This technique may be combined with other determination techniques. Increasing the number of methods used to determine an article decreases the probability of erroneously determining a non-authentic product as a genuine product.

The laminate 10 can be used in various forms as described below.
FIG. 10 is a cross-sectional view schematically showing an example of an adhesive label including the laminate shown in FIGS. 1 and 2. The pressure-sensitive adhesive label 20 includes a laminate 10 and a pressure-sensitive adhesive layer 21 provided on the back surface thereof. For example, the adhesive label 20 is attached to an article whose authenticity is to be confirmed, or is attached to another article such as a tag to be attached to the article. If it carries out like this, the authenticity of goods can be confirmed by the method mentioned above.

  The adhesive label 20 may be brittle. Such an adhesive label 20 is obtained, for example, by forming a cutout and / or a perforation in the laminate 10. When the pressure-sensitive adhesive label 20 is brittle, the laminate 10 is easily broken when the pressure-sensitive adhesive label attached to an article whose authenticity is to be confirmed is peeled off. Therefore, it becomes difficult to replace the adhesive label 20.

  FIG. 11 is a cross-sectional view schematically showing an example of a recording medium including the laminate shown in FIGS. 1 and 2. The recording medium 30 includes a paper 31 and a laminated body 10 embedded therein. An opening is provided in a portion of the paper 31 that covers the front surface of the laminate 10. Thereby, the visibility of the visualized latent image is enhanced. If the latent image can be visualized, the paper 31 does not have to be provided with the previous opening.

  The recording medium 30 can be used as a sheet for an authentication medium such as a cash card, a credit card and a passport, or a securities medium such as a gift certificate and a stock certificate, for example. Alternatively, the recording medium 30 can be used as a part of an adhesive label described later. Alternatively, the recording medium 30 can be used as a tag or a part thereof to be attached to an article whose authenticity is to be confirmed. Alternatively, the recording medium 30 can be used as a package or a part thereof for containing an article whose authenticity is to be confirmed.

  The recording medium 30 is obtained, for example, by sandwiching the laminate 10 between fiber layers during papermaking. The recording medium 30 obtained by such a method is difficult to forge.

  12 is a cross-sectional view schematically illustrating an example of an adhesive label including the recording medium of FIG. The adhesive label 40 includes a recording medium 30 and an adhesive layer 41 provided on the back surface thereof. For example, the adhesive label 40 is attached to an article whose authenticity is to be confirmed, or is attached to another article such as a base material of a tag to be attached to the article.

  FIG. 13 is a cross-sectional view schematically showing an example of a labeled article including the laminate shown in FIGS. 1 and 2. This labeled article 100 includes an article 101 and a laminate 10.

  The article 101 is an article whose authenticity is to be confirmed. The article 101 is, for example, an authentication medium such as a cash card, a credit card, and a passport, or a securities medium such as a gift certificate and a stock certificate. The article 101 may be an article other than the authentication medium and the securities medium. For example, the article 101 may be a craft or a work of art. Alternatively, the article 101 may be a packaged product including a package and contents contained therein.

  The laminate 10 is supported by the article 101. For example, the laminate 10 is attached to the article 101. In this case, for example, the laminate 10 can be supported by the article 101 by attaching the adhesive label 20 shown in FIG. 10 or the adhesive label 40 shown in FIG. 12 to the article 101.

The laminate 10 may be supported on the article 101 by other methods.
For example, when the article 101 includes paper, the laminate 10 may be embedded in the paper. In this case, the labeled article 100 is obtained, for example, by sandwiching the laminate 10 between fiber layers during papermaking, and then performing printing or the like on the paper as necessary. In order to facilitate visualization of the latent image, an opening may be provided in a portion of the paper covering the front surface of the laminate 10. Moreover, there is no restriction | limiting in particular in the shape of the laminated body 10 embedded in paper. For example, the thread-like laminate 10 may be embedded in paper.

  The laminate 10 may be supported by the article 101 by attaching a tag including the laminate 10 to the article 101. If it is difficult for a general user to replace the tag on the article 101, the laminate 10 is sufficiently useful for confirming the authenticity of the article 101.

Examples of the present invention will be described below.
A polyethylene terephthalate film in which crosslinked polystyrene fine particles having a diameter of 2 μm were dispersed as transparent particles was prepared. The film was then uniaxially stretched. In this way, a scattering type polarizing layer having a thickness of 50 μm was obtained. The transparent particles contained in this scattering type polarizing layer were optically isotropic. In this scattering type polarizing layer, the ordinary ray refractive index of the transparent matrix made of polyethylene terephthalate was equal to the refractive index of the transparent particles.

  Next, a polyimide film having a thickness of 0.1 μm was formed on the front surface of the scattering polarizing layer by a gravure coating method. This polyimide film was rubbed in a direction forming an angle of 45 ° with respect to the transmission axis of the scattering type polarizing layer to obtain an alignment film.

Next, UV curable liquid crystal UCL-008 (manufactured by Dainippon Ink Co., Ltd.) was pattern printed on the alignment film by a gravure coating method. After heating at 65 ° C. for 60 seconds, this coating film was exposed to ultraviolet light at an illuminance of 0.5 J / cm ^{2 in} a nitrogen atmosphere to cure the coating film. As a result, a birefringent layer having a difference between the ordinary light refractive index and the extraordinary light refractive index of 0.18 and a thickness of 1.5 μm was obtained. That is, this birefringent layer is a half-wave plate that transmits a pair of linearly polarized light having a wavelength λ of 540 nm and gives a phase difference of λ / 2 to the linearly polarized light.

  Thereafter, an acrylic UV ink was coated on the alignment film and the birefringent layer by a microgravure coating method to form an overcoat layer having a thickness of 5 μm.

  Next, an adhesive layer having a thickness of 30 μm containing a black dye and an acrylic adhesive was formed on the back surface of the scattering-type polarizing layer. Furthermore, a color shift ink containing a pearl pigment was printed on the overcoat layer. An adhesive label was obtained as described above.

  Next, this adhesive label was affixed on the base material. And while irradiating natural light to an adhesive label, the front surface of the adhesive label was observed first, without using an absorption type polarizing film. As a result, the region corresponding to the birefringent layer and the other region could not be distinguished. Next, the front surface of the pressure-sensitive adhesive label was observed through the absorption polarizing film while irradiating the pressure-sensitive adhesive label with natural light. As a result, the region corresponding to the birefringent layer and the other region could be seen as the bright part and the dark part, respectively. That is, the latent image could be visualized.

The top view which shows roughly the laminated body for identification which concerns on 1 aspect of this invention. Sectional drawing along the II-II line of the laminated body shown in FIG. The perspective view which shows schematically the scattering type polarizing layer which the laminated body of FIG. 1 contains. The perspective view which shows schematically the scattering type polarizing layer which the laminated body of FIG. 1 contains. The figure which shows schematically an example of the method of visualizing the latent image which the laminated body shown in FIG. 1 hold | maintains. The figure which shows schematically an example of the method of visualizing the latent image which the laminated body shown in FIG. 1 hold | maintains. The figure which shows schematically the other example of the method of visualizing the latent image which the laminated body shown in FIG. 1 hold | maintains. The top view which shows roughly the modification of the laminated body shown in FIG. Sectional drawing along the IX-IX line of the laminated body shown in FIG. Sectional drawing which shows schematically an example of the adhesive label containing the laminated body shown in FIG.1 and FIG.2. FIG. 3 is a cross-sectional view schematically showing an example of a recording medium including the laminate shown in FIGS. 1 and 2. Sectional drawing which shows schematically an example of the adhesive label containing the recording medium of FIG. Sectional drawing which shows roughly an example of the labeled article containing the laminated body shown in FIG.1 and FIG.2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Laminate for identification, 11 ... Scattering-type polarizing layer, 12 ... Birefringent layer, 13 ... Light absorption / reflection layer, 14 ... Overcoat layer, 15 ... Print pattern, 20 ... Adhesive label, 21 ... Adhesive layer, DESCRIPTION OF SYMBOLS 30 ... Recording medium, 31 ... Paper, 40 ... Adhesive label, 41 ... Adhesive layer, 100 ... Labeled article, 101 ... Article, 200 ... Verification tool, 200 '... Transparent body, 300 ... Light source, 400 ... Observer, AA1 ... area, AA2 ... area, A _T ... transmission axis, A _T '... transmission axis, L _LP ... linearly polarized light, L _N ... natural light, L _P ... P wave, L _PP ... linearly polarized light, L _PS ... linearly polarized light, L _S ... S wave.

Claims (10)

Look including the first and second portions aligned in-plane direction, and scattering-type polarizing layer the size of the light scattering changes when rotating the polarization plane of the linearly polarized light as the incident light, the front face of the polarizing layer And a birefringent layer positioned on the side and facing only at the position of the polarizing layer and the first portion, and a light absorbing layer or reflecting layer facing the back surface of the polarizing layer. Laminated body.   The laminate according to claim 1, comprising the light absorption layer.   The laminate according to claim 1, comprising the reflective layer.   An adhesive label comprising: the laminate according to any one of claims 1 to 3; and an adhesive layer supported on a back surface of the laminate.   The adhesive label according to claim 4, wherein the laminate is provided with a notch and / or a perforation.   The laminate according to any one of claims 1 to 3, wherein the laminate is embedded in the paper, an adhesive layer supported on one main surface of the paper, and a back surface facing the adhesive layer. An adhesive label characterized by comprising:   A recording medium comprising paper and the laminate according to any one of claims 1 to 3 embedded in the paper.   A labeled article comprising: an article whose authenticity is to be confirmed; and a laminate according to any one of claims 1 to 3 supported by the article whose authenticity is to be confirmed. . A method for discriminating an article whose authenticity is unknown between a genuine product and a non-genuine product,
The genuine product is a labeled article according to claim 8,
An article of unknown authenticity is non-authentic if the article of unknown authenticity does not include a light-scattering region that holds a latent image that is visualized by viewing through a polarizer. The method characterized by including judging. A method for discriminating an article whose authenticity is unknown between a genuine product and a non-genuine product,
The genuine product is a labeled product comprising an article whose authenticity is to be confirmed and a laminate according to claim 3 supported by the article whose authenticity is to be confirmed,
When the article whose authenticity is unknown is visualized by observing through a polarizer and does not hold a latent image in which the position of the bright part and the dark part is switched by changing the observation angle in the visualized state And determining that the article with unknown authenticity is a non-authentic item.

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