JP2012013839A - Display body, article with display body, and method for determining truth/falsehood - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exert a higher anticounterfeit effect.SOLUTION: Means for solving the problem in accordance with the present invention is a display body (9) formed by assembling a first optic effect layer (14) with a second optic effect layer (11). The first optic effect layer (14) includes a first interface section (IF1) having a diffraction grating in which a distance between grating lines is at least within a range from 200 nm to 500 nm and having a reflective material layer (13) partially provided therein, and the second optic effect layer (11) has an optical absorption layer (10) and is provided with cholesteric liquid crystal.

Description

  The present invention relates to, for example, a table itself that provides an anti-counterfeit effect, a decoration effect, and / or an aesthetic effect, an article with the table itself, and a method for determining authenticity thereof.

  Articles such as securities, certificates, branded products and personal authentication media are desired to be difficult to counterfeit. For this reason, such an article may support a display body having an excellent anti-counterfeit effect.

  Many of such displays include fine structures such as diffraction gratings, holograms, and lens arrays. These microstructures are difficult to analyze. Further, in order to manufacture a display body including these fine structures, expensive manufacturing equipment such as an electron beam drawing apparatus is required. Therefore, such a display body can exhibit a high anti-counterfeit effect.

  For example, in Patent Document 1, a first interface portion provided with a relief type diffraction grating composed of a plurality of grooves and a two-dimensionally smaller inter-grating distance than the minimum inter-grating distance of the plurality of grooves. There is described a display body including a second interface portion that is arranged and has a plurality of concave portions or convex portions each having a forward tapered shape. This display body includes a high-definition structure and has special optical characteristics. Therefore, this display has a high anti-counterfeit effect.

JP 2008-107470 A

  This invention makes it a subject to implement | achieve the higher forgery prevention effect.

  In order to solve the above-mentioned problems in the present invention, first, in the invention of claim 1, the first interface portion having at least a diffraction grating having a distance between the gratings of 200 nm to 500 nm and partially provided with a reflective material layer. And a second optical effect layer having a light absorption layer and provided with a cholesteric liquid crystal.

  According to a second aspect of the present invention, the first optical effect layer includes a third interface portion provided with a plurality of diffraction gratings arranged with a larger interstitial distance than the interstitial distance of the first interface portion. The display body according to claim 1, further comprising:

  According to a third aspect of the invention, there is provided a display-equipped article comprising a base material and the display body according to any one of the first or second aspect supported by the base material. It is.

  The invention according to claim 4 is the article with a display body according to claim 3, wherein the substrate is paper, and a part of the display body is embedded in the paper. It is.

  The invention according to claim 5 is the article with a display body according to claim 3, wherein the base material is paper, and the display body is transferred onto the surface of the paper. is there.

  According to a sixth aspect of the present invention, there is provided a method for determining whether or not the display body according to the first or second aspect or the article with the display body according to any one of the third to fifth aspects is authentic, In addition to the contrast ratio of the image of illuminating the body and observing the reflected light in the specular direction and the image of the reflected light observed through the circularly polarizing plate, the reflected light was observed through the linearly polarizing plate. The authenticity determination method is characterized in that the image is determined to be authentic only when the contrast ratios of the images are different.

  The present invention has an effect of realizing a higher anti-counterfeit effect.

The top view which shows roughly the display body which concerns on one Embodiment of this invention. Sectional drawing along the II-II line of the display body shown in FIG. The perspective view which shows an example of the structure employable as the 3rd interface part of the display body shown in FIG.1 and FIG.2. The perspective view which shows an example of the structure employable as the 1st interface part of the display body shown in FIG.1 and FIG.2. The figure which shows schematically the optical effect which the part corresponding to the 3rd interface part shows among the display bodies shown in FIG.1 and FIG.2. The figure which shows schematically the optical effect which the part corresponding to the 1st interface part shows among the display bodies shown in FIG.1 and FIG.2. Sectional drawing which shows schematically the adhesive label which concerns on one Embodiment of this invention. Sectional drawing which shows schematically the transfer foil which concerns on one Embodiment of this invention.

  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 display body according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line II-II of the display shown in FIG. 1 and 2, directions parallel to the main surface of the display body 9 and orthogonal to each other are defined as an X direction and a Y direction, and a direction perpendicular to the main surface of the display body 9 is defined as a Z direction.

  As shown in FIG. 2, the display body 9 includes a light absorption layer 10, a second optical effect layer 11, a light transmission layer 12, a reflective material layer 13, a first optical effect layer 14, and a light transmission layer. Layer 15. The interface between the first optical effect layer 14 and the reflective material layer 13 includes a first interface part IF1, a second interface part IF2, and a third interface part IF3. As will be described later, the first interface portion IF1 is provided with a plurality of diffraction gratings, the second interface portion IF2 is a flat surface, the reflective material layer 13 is demetalized, and the third interface portion. The IF 3 is provided with a plurality of grooves.

Hereinafter, the portion of the first interface IF1 that is covered with the reflective material layer 13 is referred to as a first region. Further, a portion of the second interface portion IF2 where the reflective material layer 13 is demetalized is referred to as a second region. And the part coat | covered with the reflective material layer 13 among 3rd interface part IF3 is called 3rd area | region. In addition, below, the part corresponding to the 1st field among display bodies 9 is called display part DP1. Moreover, the part corresponding to the 2nd area | region among the display bodies 9 is called display part DP2. And the part corresponding to the 3rd field among display bodies 9 is called display part DP3.

  The light absorption layer 10 is typically a sheet or film made of a resin in which carbon black is dispersed. As this resin, for example, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, triacetyl cellulose, polypropylene, polymethyl methacrylate, acrylic styrene copolymer, and vinyl chloride are used.

  The first optical effect layer 14 typically has optical transparency. As the material of the first optical effect layer 14, for example, a thermoplastic resin, a thermosetting resin, and a resin such as an ultraviolet ray or an electron beam curable resin (hereinafter also referred to as a photocurable resin) are used. When a thermoplastic resin, a thermosetting resin, or a photocurable resin is used as the material of the first optical effect layer 14, a concave structure and / or a convex structure is easily formed on one main surface by transfer using the original plate. can do.

  Examples of the light-transmitting thermoplastic resin include polyethylene terephthalate, polyethylene naphthalate, polycarbonate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, nitrocellulose, polyethylene, polypropylene, acrylic styrene copolymer, vinyl chloride, and the like. Polymethyl methacrylate is mentioned.

  Examples of the light curable thermosetting resin include polyimide, polyamide, polyester urethane, acrylic urethane, epoxy urethane, silicone, epoxy, and melamine resin.

  The photocurable resin refers to a resin that is cured by irradiation with light such as ultraviolet rays and electron beams. Typical resins that undergo radical polymerization by light irradiation include acrylic resins having an acryloyl group in the molecule. For example, epoxy acrylate, urethane acrylate, polyester acrylate or polyol acrylate oligomers or polymers, simple resins, and the like. Functional, bifunctional or polyfunctional polymerizable (meth) acrylic monomers (for example, tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, tri Methylolpropane triacrylate, pentaerythritol triacrylate or pentaerythritol tetraacrylate) or its oligomers Polymer, or a mixture thereof is used.

  When a photocurable resin is used as the material of the first optical effect layer 14, this layer may further contain a photopolymerization initiator. Examples of this photopolymerization initiator include benzophenone, diethylthioxanthone, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [ 4- (methylthio) phenyl] -2-morpholinopropane-1 and acylphosphine oxide. However, the photopolymerization initiator does not react 100%, and unreacted ones may adversely affect the performance. Therefore, the addition amount of the photopolymerization initiator is, for example, 0.1 to 7% by mass, typically 0.5 to 5% by mass with respect to the photocurable resin, and no uncured part remains. It is preferable to keep it to the extent.

  On one main surface of the first optical effect layer 14, a first interface part IF1 to a third interface part IF3 are provided. The structure and optical characteristics of the first interface part IF1 to the third interface part IF3 will be described in detail later.

  The reflective material layer 13 covers at least a part of the first interface part IF1 to the third interface part IF3. 1 and 2 illustrate, as an example, a case where the reflective material layer 13 covers the entire first interface portion IF1 to third interface portion IF3 except for the second region.

  As the reflective material layer 13, for example, a metal or alloy layer made of a metal material such as aluminum, silver, tin, chromium, nickel, copper, gold, and alloys thereof can be used. In this case, the reflective material layer 13 is typically formed using a vacuum film forming method. Examples of the vacuum film forming method include a vacuum deposition method and a sputtering method. The thickness of the reflective material layer 13 is, for example, in the range of 1 nm to 100 nm.

  The reflective material layer 13 plays a role of causing the display body 9 to display an image with better visibility. Further, by providing the reflective material layer 13, it is possible to make it difficult to cause damage to the concave structure and / or the convex structure provided on one main surface of the first optical effect layer.

  The light transmission layer 12 is interposed between the reflective material layer 13 and the second optical effect layer 11. The light transmission layer 12 plays a role of improving the adhesion between these layers.

  The light transmissive layers 12 and 15 are light transmissive and are typically transparent. Examples of the material of the light transmission layer 12 include vinyl acetate resin, ethylene vinyl acetate copolymer resin, polyester resin, polyester urethane resin, acrylic urethane resin, epoxy resin, epoxy urethane resin, polycarbonate urethane resin, butyral resin, and chlorinated propylene. Resin.

  The second optical effect layer 11 includes a portion facing the first optical effect layer 14 at the position of the reflective material layer 13. 1 and 2 illustrate, as an example, a case where the second optical effect layer 11 faces the entire first optical effect layer 14 with a portion where the reflective material layer 13 is demetalized interposed therebetween. Yes.

  The second optical effect layer 11 includes at least one of a cholesteric liquid crystal, a pearl pigment, and a multilayer interference film. The second optical effect layer 11 typically includes cholesteric liquid crystal.

  When the second optical effect layer 11 includes a cholesteric liquid crystal, the second optical effect layer 11 has, for example, a material containing a compound having a cholesteric structure, or a nematic liquid crystal having a cholesteric structure by adding a chiral agent. It can be manufactured using a material containing the above. The cholesteric liquid crystal can change the helical pitch and the twist direction of the polarization plane by changing the amount and type of the chiral agent added to the nematic liquid crystal, for example. In addition, a polymerizable group such as an acrylic group can be introduced at both ends of the liquid crystal molecule. This makes it possible to fix the alignment after aligning each liquid crystal molecule.

  When the second optical effect layer 11 includes a cholesteric liquid crystal, the second optical effect layer 11 may be a layer made of cholesteric liquid crystal or a layer containing a cholesteric liquid crystal pigment.

  When the second optical effect layer 11 is a layer made of cholesteric liquid crystal, light scattering in the second optical effect layer 11 can be minimized.

When the second optical effect layer 11 is a layer containing a cholesteric liquid crystal pigment, the second optical effect layer 11 typically contains a powder of cholesteric liquid crystal and a transparent binder. In this case, for example, the optical characteristics of the second optical effect layer 11 can be finely adjusted by using a plurality of cholesteric liquid crystal pigments having different helical pitches and twisted directions of the polarization planes.

  When the second optical effect layer 11 includes cholesteric liquid crystal, when the second optical effect layer 11 is illuminated, the second optical effect layer 11 can emit circularly polarized selective reflection light. In the following, it is assumed that the alignment axis of the cholesteric liquid crystal is substantially parallel to the main surface of the display body 9.

  It is known that if the helical pitch of the cholesteric liquid crystal is P, the incident angle with reference to an axis parallel to the main surface of the display body 9 is θ, and the wavelength of the reflected light is λ, the following equation holds: Yes.

  2P · sin θ = nλ (n = 1, 2, 3,...)

  According to this equation, for example, when white light is incident on the second optical effect layer 11 perpendicularly, that is, when θ = 90 °, regular reflection light having a wavelength twice the helical pitch P is reflected by the second optical effect layer 11. Injected perpendicular to the effect layer 11.

  For example, when a cholesteric liquid crystal having a helical pitch P of 280 nm is used, the second optical effect layer 11 can emit light (wavelength λ = 560 nm) corresponding to a green hue. Alternatively, when a cholesteric liquid crystal having a helical pitch P of 360 nm is used, the second optical effect layer 11 can emit light (wavelength λ = 720 nm) corresponding to a red hue. As described above, by changing the helical pitch P of the cholesteric liquid crystal, the optical characteristics of the second optical effect layer 11 including the cholesteric liquid crystal can be changed.

  When the incident angle θ of the illumination light is gradually reduced, the wavelength of light emitted from the second optical effect layer 11 is gradually shortened, and finally becomes shorter than the shortest wavelength of visible light. That is, in this case, the hue of the emitted light changes from red to green and from green to blue, and finally the emitted light becomes invisible. For example, when a cholesteric liquid crystal having a helical pitch P of 360 nm is used and the incident angle θ is 30 ° (60 ° with respect to the normal direction of the main surface of the display body 9), the wavelength of the selectively reflected light is 360 nm. Therefore, in this case, the observer cannot visually recognize the visual effect due to the second optical effect layer 11 or is extremely difficult to visually recognize.

  The second optical effect layer 11 containing cholesteric liquid crystal is formed as follows, for example.

  First, stretched films such as polyethylene terephthalate, polypropylene, nylon, cellophane, and polyvinyl alcohol are prepared. This stretched film may be rubbed. Next, a coating liquid in which a cholesteric liquid crystal raw material is dissolved in an organic solvent is prepared. Next, this coating solution is applied onto the stretched film. Then, the obtained coating film is dried. Thereby, liquid crystal molecules are aligned on the stretched film. In this state, ultraviolet rays are irradiated to fix the alignment of the liquid crystal molecules. In this way, a cholesteric liquid crystal forming film is obtained.

Next, the first optical effect layer 14 is formed by depositing the reflective material layer 13 and then pattern-demetallized laminated base material, applying the light transmission layer 12 as an adhesive, and forming the second optical effect layer 11. Paste it on top. In this way, the second optical effect layer 11 containing cholesteric liquid crystal is formed under one main surface of the transfer target, for example, the first optical effect layer 14 or the reflective material layer 13.

  When the second optical effect layer 11 contains a pearl pigment, the second optical effect layer 11 is made of, for example, a powder of a layered substance such as mica, or a layered substance made of a coating material such as reduced titanium dioxide and iron oxide. It contains powder that is coated. Alternatively, in this case, the second optical effect layer 11 may be a powder obtained by pulverizing a multilayer interference film described later. When the second optical effect layer 11 includes a pearl pigment, the second optical effect layer 11 typically further includes a transparent binder.

  The color of the second optical effect layer 11 changes depending on the change in the observation angle. The optical characteristics resulting from the combination of the second optical effect layer 11, the first optical effect layer 14, the reflective material layer 13, and the portion obtained by demetalizing the reflective material layer 13 will be described in detail later.

  FIG. 3 is an enlarged perspective view showing an example of a structure that can be employed in the third interface part IF3 of the display body shown in FIGS. FIG. 4 is an enlarged perspective view showing an example of a structure that can be employed in the first interface portion IF1 of the display body shown in FIGS.

  As shown in FIG. 4, the first interface portion IF <b> 1 is provided with a plurality of concave portions or convex portions 22. These concave portions or convex portions 22 are arranged in a corrugated shape with a minimum interstitial distance within a range of 200 nm to 500 nm. The recesses or protrusions 22 are regularly arranged. The depth or height of the concave portion or convex portion 22 is in the range of 0.3 μm to 0.5 μm. The ratio of the depth or height to the interstitial distance of the recesses or projections 22 (hereinafter also referred to as aspect ratio) is in the range of 0.5 to 1.5, for example.

  When the concave or convex portion 22 is corrugated, the concave or convex portion 22 may have a sharp tip or a truncated shape. However, when the concave portion or the convex portion 22 has a conical shape with a sharp tip, the concave portion or the convex portion 22 does not have a surface parallel to the first interface portion IF1, so that it is compared with a truncated shape. The reflectance of the regular reflection light at the first interface portion IF1 can be further reduced.

  By the way, as another example of the arrangement pattern of the concave portions or the convex portions that can be employed in the first interface portion, the arrangement of the concave portions or the convex portions 22 may form a square lattice. This structure is relatively easy to manufacture using a microfabrication device such as an electron beam drawing device or a stepper, and highly accurate control of the inter-lattice distance of the concave or convex portions 22 is also relatively easy.

  Further, when the arrangement of the concave or convex portions 22 is a regular lattice, the inter-lattice distance is the same in the X direction and the Y direction, but the inter-lattice distance of the concave or convex portions 22 may be different between the X direction and the Y direction. Good. That is, the arrangement of the concave portions or the convex portions 22 may form a rectangular lattice.

  When the interstitial distance between the concave portions or the convex portions 22 is set to be relatively long in both the X direction and the Y direction, the display body 9 is illuminated from the direction perpendicular to the X direction when the display body 9 is illuminated from the direction perpendicular to the Y direction. The diffracted light can be emitted from the first interface IF1 both in the case of illumination, and the wavelength of the diffracted light can be made different between the former and the latter. When the interstitial distance of the concave or convex portions 22 is set to be relatively long in one of the X direction and the Y direction, and set to be relatively short on the other side, the display body 9 is illuminated from a direction perpendicular to one of the Y direction and the X direction. In this case, diffracted light is emitted from the first interface IF1, and when the display body 9 is illuminated from a direction perpendicular to the other of the Y direction and the X direction, emission of the diffracted light from the first interface IF1 is prevented. it can.

It is difficult to accurately analyze the fine structure provided in the first interface IF1 from the display body 9. Further, even if the previous fine structure can be analyzed from the completed display body 9, forgery or imitation of the display body including this fine structure is difficult. In the case of a diffraction grating, the structure may be copied as interference fringes by an optical duplication method using laser light or the like, but the fine structure of the first interface portion IF1 cannot be duplicated.

  Hereinafter, the optical effect resulting from the combination of the first optical effect layer 14, the reflective material layer 13, the light absorption layer 10, the second optical effect layer 11, and the portion where the reflective material layer 13 is demetallized will be described.

  First, the optical effect of the display unit DP3 will be described.

  FIG. 5 is a diagram schematically showing an optical effect indicated by a portion corresponding to the third interface portion in the display body shown in FIGS. 1 and 2. In FIG. 5, 31 indicates illumination light, 32 indicates regular reflection light or zero-order diffracted light, and 33 indicates first-order diffracted light.

The plurality of grooves in the third interface portion constitute a diffraction grating. When this diffraction grating is illuminated, the diffraction grating emits strong diffracted light 33 in a specific direction with respect to the traveling direction of the illumination light 31 that is incident light. . The emission angle β _m of the _{m-th order} diffracted light can be calculated from the following equation (1) when light travels in a plane perpendicular to the grating line of the diffraction grating (m = 0, ± 1, ± 2,... ).

d = mλ / (sin α−sin β _m ) (1)

In this equation (1), d represents the grating constant of the diffraction grating, and λ represents the wavelengths of incident light and diffracted light. Α represents the exit angle of 0th-order diffracted light, that is, transmitted light or specularly reflected light. In other words, the absolute value of α is equal to the incident angle of the illumination light, and the incident angle is symmetrical with respect to the Z axis (in the case of a reflective diffraction grating). For α and β _m , the clockwise direction from the Z axis is the positive direction.

The most representative diffracted light is the first-order diffracted light 33. As is clear from the equation (1), the emission angle β ₁ of the _first-order diffracted light 33 changes according to the wavelength λ. That is, the diffraction grating functions as a spectroscope. Accordingly, when the illumination light is white light, the color perceived by the observer changes when the observation angle is changed in a plane perpendicular to the grating line of the diffraction grating.

  In addition, the color perceived by the observer under a certain observation condition changes according to the lattice constant d.

As an example, it is assumed that the diffraction grating emits the first-order diffracted light 33 in the normal direction. That is, the emission angle β ₁ of the _first-order diffracted light 33 is assumed to be 0 °. Assume that the observer perceives the first-order diffracted light 33. When the exit angle of the zero-order diffracted light 32a at this time is alpha _N, (1) formula can be simplified to the following equation (2).

d = λ / sin α _N (2)

As apparent from the equation (2), in order for the observer to perceive a specific color, the wavelength λ corresponding to the color, the incident angle | α _N | of the illumination light 31, and the lattice constant d are expressed as ( It may be set so as to satisfy the relationship shown in 2). For example, white light including all light components having a wavelength in the range of 400 nm to 700 nm is used as the illumination light 31, and the incident angle | α _N | of the illumination light 31 is set to 45 °. It is assumed that a diffraction grating having a spatial frequency (reciprocal of the grating constant) distributed within a range of 1000 lines / mm to 1800 lines / mm is used. In this case, when the diffraction grating is observed from the normal direction, a portion having a spatial frequency of about 1600 lines / mm looks blue and a portion having a spatial frequency of about 1100 lines / mm looks red.

  Note that the diffraction grating is easier to form when the spatial frequency is smaller. Therefore, in a normal display body, the majority of diffraction gratings are diffraction gratings having a spatial frequency of 500 lines / mm to 1600 lines / mm.

  As described above, the color perceived by the observer under a certain observation condition can be controlled by the grating constant d (or spatial frequency) of the diffraction grating. When the observation angle is changed from the previous observation condition, the color perceived by the observer changes.

  FIG. 6 is a diagram schematically illustrating an optical effect exhibited by a portion corresponding to the first interface portion of the display body illustrated in FIGS. 1 and 2. In FIG. 6, 36 indicates illumination light, 37 indicates regular reflection light, and reflected light 38 indicates first-order diffracted light.

  When the first interface part IF1 and the third interface part IF3 coexist, the plurality of recesses or protrusions 22 provided in the first interface part IF1 are arranged in the same direction. For this reason, since the concave portions or the convex portions 22 are regularly arranged in a corrugated shape, the first interface portion IF1 emits the reflected light 37 as polarized light in only one direction having linear polarization. Moreover, the diffracted light 38 in which both polarized lights are mixed is emitted.

  Moreover, the reflectance of the regular reflection light 37 of the first interface portion IF1 is small regardless of the angle at which each concave portion or convex portion 22 is observed. Therefore, the influence of the specularly reflected light 37 emitted from the first interface portion IF1 on the light emitted from the display portion DP2 and the display portion DP3 is small.

  In addition, if the emission angle of the primary reflected light from the first interface portion IF1 is larger than −90 °, the observer can appropriately set the angle formed by the normal direction of the display body 9 and the observation direction. The primary reflected light from the first interface part IF1 can be perceived. Therefore, in this case, it can be visually confirmed that the display portion DP2 is different from the layer including at least one of the cholesteric liquid crystal, the pearl pigment, and the multilayer interference film.

  As described above, the minimum interstitial distance of the concave portion or the convex portion 22 is in the range of 200 nm to 500 nm. If the minimum inter-lattice distance is reduced, it may be difficult to emit reflected light from the first interface IF1. When the minimum inter-grating distance is increased, the emission angle of the reflected light is reduced, and it may be difficult to reduce the intensity of the diffracted light emitted from the first interface portion IF1.

  Moreover, in this display body 9, the concave structure and / or convex structure corresponding to the groove | channel 21 and the recessed part or the convex part 22 are formed in one original, and this concave structure and / or convex structure are made into the 2nd optical effect layer. 11, the groove 21 and the concave portion or the convex portion 22 can be simultaneously formed. In addition, the features of the fine concave structure and / or convex structure enable high-definition image display and facilitate distinction from those produced by other methods. The fact that genuine products can be manufactured stably with extremely high accuracy makes it easier to distinguish between counterfeit products and counterfeit products.

  Next, the optical effect of the display unit DP2 will be described.

  As described above, the second interface portion IF2 is a flat surface, and the illumination light is incident on the second interface portion IF2 as a portion where the second region is not covered with the reflective material layer 13.

  The display 9 shown in FIG.1 and FIG.2 exhibits a very special visual effect according to the incident angle of illumination light, and the observation angle of an observer.

Hereinafter, the angle range including the emission direction of the specularly reflected light with respect to the specific illumination light on the basis of the normal direction of the display body 9 is referred to as “positive angle range”, and the angle including the incident direction of the specific illumination light. The range is called “negative angle range”. The illumination light is assumed to be white light.

  First, consider a case in which illumination light is incident only from a negative angle range and the display body 9 is observed from a positive angle range. In this case, the display part DP2 shows the optical effect due to the second optical effect layer 11 very clearly. That is, the display part DP2 is visually recognized as an area showing different colors depending on the observation angle. In this case, the display unit DP2 is usually observed together with the region where the diffraction grating is provided. In this case, the display unit DP3 is usually observed as a mirror surface. That is, in the display unit DP3, light having a wavelength corresponding to the illumination light is visually recognized when the specularly reflected light is observed from an angle where it can be observed. As described above, when the display body 9 is observed from the positive angle range, the display body 9 includes an area showing a different color according to the observation angle, an area provided with a diffraction grating, and an area provided with a mirror surface. It is visually recognized as including.

  Next, consider a case in which illumination light is incident only from the negative angle range and the display body 9 is observed from the negative angle range. In this case, when the incident angle and the observation angle of the illumination light are deep, that is, when the absolute values of the incident angle and the observation angle are large, the observer can visually recognize the diffracted light from the display unit DP1. Therefore, for example, when the position of the light source of the illumination light and the position of the observer are fixed and the angle formed by these and the display body 9 is changed, the visual effect is discontinuously changed in the display unit DP1. Occurs. Specifically, when the incident angle and the observation angle are increased, the diffracted light from the display unit DP1 can be observed at a certain angle.

  Next, assuming that there are two or more light sources of illumination light, assuming a room where fluorescent lamps are provided at a plurality of locations. Specifically, as an example, consider a case where there is a first light source that makes the first illumination light enter from a negative angle range and a second light source that makes the second illumination light enter from a positive angle range. In this case, for example, when the position of the first and second light sources and the position of the observer are fixed and the angle formed by these and the display body 9 is changed, the visual effect is discontinuous in the display unit DP1. Changes occur. Specifically, when the observation angle is shallow, the display unit DP1 causes a continuous color change due to the second optical effect layer 11. When the incident angle and the observation angle are deepened, the diffracted light from the display unit DP1 can be observed with a certain angle as a boundary.

  In the display body 9 shown in FIGS. 1 and 2, the first interface part IF1 and the second interface part IF2 are adjacent to each other. The reflective material layer 13 covers both of them so as to cross the boundary between the first interface part IF1 and the second interface part IF2. Further, the second optical effect layer 11 is configured such that the orthogonal projection of the first optical effect layer 14 onto the main surface including the interface portions IF1 and IF2 crosses the boundary between the first interface portion IF1 and the second interface portion IF2. Is provided.

  When such a configuration is employed, the boundary between the display portion DP1 and the display portion DP2 can be determined with high accuracy. Therefore, this makes it possible to display a high-definition pattern corresponding to the boundary between the first interface portion IF1 and the second interface portion IF2 on the display body 9.

  In the display body 9 shown in FIGS. 1 and 2, the first interface part IF1 and the third interface part IF3 are adjacent to each other. The reflective material layer 13 covers both of them so as to cross the boundary between the first interface part IF1 and the third interface part IF3. Further, the second optical effect layer 11 is configured such that the orthogonal projection of the first optical effect layer 12 onto the main surface including the interface portions IF1 and IF3 crosses the boundary between the first interface portion IF1 and the third interface portion IF3. Is provided.

The boundary between the first interface portion IF1 and the third interface portion IF3 can be determined with high accuracy by techniques such as electron beam drawing and nanoimprint. Therefore, when such a configuration is adopted, the boundary between the display portion DP1 and the display portion DP3 can be determined with high accuracy. Therefore, this makes it possible to display a high-definition pattern corresponding to the boundary between the first interface part IF1 and the third interface part IF3 on the display body 9.

  Thus, the display body 9 has a very special visual effect. And it is impossible or extremely difficult for a person who attempts to counterfeit to reproduce such a visual effect. That is, the display body 9 has a high anti-counterfeit effect.

  When the second optical effect layer 11 includes cholesteric liquid crystal, the second optical effect layer 11 can emit circularly polarized selective reflection light. Further, the present inventors have found that the diffracted light emitted from the first interface IF1 has linear polarization. Therefore, when the second optical effect layer 11 includes a cholesteric liquid crystal, it is possible to track the change of the emitted light based on the difference in polarization. That is, in this case, the display body 9 is also useful as an anti-counterfeit medium for covert.

  Examples of a method for discriminating an article for which it is unknown whether or not it is a genuine product between a genuine product and a non-genuine product include the following methods.

  First, as a first operation, the display body 9 is illuminated with illumination light having an absolute angle of incidence of less than 60 °. At this time, it is confirmed that the optical effect due to the display portion DP2 is observed in an angle range where the absolute value is less than 60 °. For example, when the second optical effect layer 11 includes a cholesteric liquid crystal, it is confirmed that selective reflected light from the display unit DP2 is emitted in this angular range.

  Next, as a second operation, the display body 9 is illuminated with illumination light whose absolute angle of incidence is 60 ° or more and less than 90 °. At this time, it is confirmed that the optical effect due to the first interface IF1 is observed in an angle range in which the absolute value is 60 ° or more and less than 90 ° and the above incident angle is equal to positive and negative. That is, it is confirmed that diffracted light from the first interface IF1 is observed in this angular range.

  When the above optical effects are observed in both the first and second operations, the article is determined to be genuine. On the other hand, if any of the above optical effects is not observed in any one of the first and second operations, the article is determined to be a non-genuine product.

  In addition, when the 2nd optical effect layer 11 contains a cholesteric liquid crystal, you may discriminate | determine between a genuine product and a non-authentic product as follows. That is, in the first operation, circularly polarized light is emitted in an angle range in which the absolute value is less than 60 °, and in the second operation, the absolute value is 60 ° or more and less than 90 ° and the incident angle described above. If the linearly polarized light is emitted in an angle range in which positive and negative are equal, the article may be determined to be genuine. In addition, this judgment can be performed by observing the display body 9 via polarizing plates, such as a circularly-polarizing plate and a linearly-polarizing plate, for example.

  The display body 9 described above may be used as, for example, an adhesive label such as a seal label, a transfer foil such as a stripe transfer foil and a spot transfer foil, or a part of a thread.

  FIG. 7 is a cross-sectional view schematically showing an adhesive label according to an embodiment of the present invention. An adhesive label 100 shown in FIG. 7 includes the display body 9 shown in FIGS. 1 and 2 and an adhesive layer 30 provided on the display body 9.

The adhesive layer 30 is provided on the main surface of the light absorbing layer 10 on the side opposite to the first optical effect layer 14. The adhesive layer 30 faces the first optical effect layer 14 with the second optical effect layer 11 and the reflective material layer 13 interposed therebetween. As a material for the pressure-sensitive adhesive layer 30, for example, a pressure-sensitive adhesive is used. For example, the pressure-sensitive adhesive layer 30 is formed by applying the mixture of the pressure-sensitive adhesive and the solvent by a method such as gravure coating, roll coating, screen coating, and blade coating. In addition, the thickness of the adhesion layer 30 shall be in the range of 1 micrometer thru | or 10 micrometers, for example.

  The adhesive label 100 is affixed to, for example, an article whose authenticity is to be confirmed, or is attached to another article such as a tag base material to be attached to such an article. Thereby, the forgery prevention effect can be provided to the said article | item.

  In addition, the sticking prevention function can also be provided to the pressure-sensitive adhesive label 100 by further providing a brittle layer between the display body 9 and the pressure-sensitive adhesive layer 30. Thereby, a further higher forgery prevention effect can be achieved.

  FIG. 8 is a cross-sectional view schematically showing a transfer foil according to an embodiment of the present invention. A transfer foil 200 shown in FIG. 8 includes the display body 9 shown in FIGS. 1 and 2 and a support layer 43 that supports the display body 9 in a peelable manner. In FIG. 8, as an example, a release layer 45 is provided between the light transmission layer 15 and the support layer 43, and the main surface of the light absorption layer 10 is on the side opposite to the first optical effect layer 14. The case where the adhesive bond layer 41 is provided on the main surface is drawn.

  The support layer 43 is, for example, a film or sheet made of resin. As a material of the support layer 43, for example, polyethylene terephthalate resin, polyethylene naphthalate resin, polyimide resin, polyethylene resin, polypropylene resin, or vinyl chloride resin is used.

  The peeling layer 45 plays a role of facilitating peeling of the support layer 43 when the transfer foil 200 is transferred to the transfer target. As the material of the release layer 45, for example, the resin mentioned above as the material of the first optical effect layer 14 is used. The release layer 45 may contain additives such as paraffin wax, carnauba wax, polyethylene wax, and silicone. Note that the thickness of the release layer 45 is, for example, in the range of 0.5 μm to 5 μm.

  As the material of the adhesive layer 41, for example, an adhesive such as a reactive curable adhesive, a solvent-volatile adhesive, a hot melt adhesive, an electron beam curable adhesive, and a heat sensitive adhesive is used.

  As the reaction curable adhesive, for example, polyurethane resins such as polyester urethane, polyether urethane, and acrylic urethane, or epoxy resins are used.

  Solvent volatilization type adhesives include, for example, aqueous emulsion adhesives including vinyl acetate resin, acrylate copolymer resin, ethylene-vinyl acetate copolymer resin, ionomer resin and urethane resin, natural rubber, styrene-butadiene A latex adhesive containing a copolymer resin and an acrylonitrile-butadiene copolymer resin is used.

  As the hot melt adhesive, for example, an adhesive containing ethylene-vinyl acetate copolymer resin, ethylene-ethyl acrylate copolymer resin, polyester resin, polycarbonate resin, polyvinyl ether resin, polyurethane resin, or the like as a base resin is used.

As the electron beam curable adhesive, for example, an adhesive mainly containing an oligomer having one or more vinyl functional groups such as acryloyl group, allyl group and vinyl group is used. For example, as an electron beam curable adhesive, a mixture of polyester acrylate, polyester methacrylate, epoxy acrylate, epoxy methacrylate, urethane acrylate, urethane methacrylate, polyether acrylate or polyether methacrylate and an adhesion-imparting agent can be used. As the adhesion-imparting agent, for example, an acrylate containing phosphorus or a derivative thereof, or an acrylate containing a carboxy group or a derivative thereof is used.

  As the heat-sensitive adhesive, for example, polyester resin, acrylic resin, vinyl chloride resin, polyamide resin, polyvinyl acetate resin, rubber resin, ethylene-vinyl acetate copolymer resin, or vinyl chloride-vinyl acetate copolymer resin is used.

  The adhesive layer 41 is obtained, for example, by applying the above-described resin onto the light absorption layer 10 using a coater such as a gravure coater, a micro gravure coater, or a roll coater.

  The transfer foil 200 is transferred to a transfer target by, for example, a roll transfer machine or a hot stamp. At this time, peeling occurs in the peeling layer 45, and the display body 9 is stuck to the transfer body via the adhesive layer 41.

  As described above, the display body 9 has an excellent anti-counterfeit effect. Therefore, when the display body 9 is supported by an article, it is difficult to forge the genuine article with the display body. In addition, since the display body 9 has the visual effect described above, it is easy to determine an article whose authenticity is unknown from a genuine product to a non-genuine product.

DESCRIPTION OF SYMBOLS 9 ... Display body 10 ... Light absorption layer 11 ... 2nd optical effect layer 12 ... Light transmission layer 13 ... Reflective material layer 14 ... 1st optical effect layer 15 ... Light transmission layer 21 ... Groove 22 ... Concave or convex part 30 ... Adhesion Layer 31 ... Illumination light 32 ... Regular reflection light or 0th order diffracted light 33 ... First order diffracted light 36 ... Illumination light 37 ... Reflected light 38 ... Diffracted light 41 ... Adhesive layer 43 ... Support layer 45 ... Release layer 100 ... Adhesive label 200 ... transfer foil,
DP1 ... display part DP2 ... display part DP3 ... display part IF1 ... first interface part IF2 ... second interface part IF3 ... third interface part

Claims (6)

  A cholesteric liquid crystal having a first optical effect layer including a first interface having at least a diffraction grating having an interstitial distance in the range of 200 nm to 500 nm, partially including a reflective material layer, and a light absorbing layer. A display body comprising a combination of the provided second optical effect layer.   The first optical effect layer further includes a third interface portion provided with a plurality of diffraction gratings arranged at a larger interstitial distance than the interstitial distance of the first interface portion. The display body according to claim 1.   An article with a display body, comprising: a base material; and the display body according to claim 1 supported by the base material.   The article with a display body according to claim 3, wherein the substrate is paper, and a part of the display body is embedded in the paper.   The article with a display body according to claim 3, wherein the base material is paper, and the display body is transferred onto a surface of the paper.   A method for determining whether the display body according to claim 1 or 2 or the article with a display body according to any one of claims 3 to 5 is authentic, wherein the display body is illuminated to make a regular reflection direction. In addition to the difference in contrast ratio between the image when the reflected light is observed and the image obtained by observing the reflected light through the circularly polarizing plate, only when the contrast ratio of the image when the reflected light is observed through the linearly polarizing plate is different. A method for determining authenticity, wherein the authenticity is determined to be authentic.

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