JP2009034945A - Labeling element, labeled article, and determination method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide forgery preventing technique capable of achieving high forgery preventing efficiency. <P>SOLUTION: This labeling element 10 is attached to the article and is used for checking whether the article is a true product or not, and is provided with a selection reflection layer generating selection reflection when white light as natural light is irradiated, and the labeling element 10 includes a transmissive range R<SB>T</SB>that the article positioned on a back surface side of the labeling element is seen through when being observed from a front surface side of the labeling element, and at least a part of the transmissive range R<SB>T</SB>generates selection reflection when the white light as the natural light is irradiated from the front surface side or the back surface side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a forgery prevention technique.

  Bills, checks, credit cards, bank cards, prepaid cards, commuter passes, deposits and savings passbooks, passports, and identification cards may be used in various ways if they are used illegally by falsification or tampering. Therefore, for these purposes, for the purpose of preventing or suppressing unauthorized use, a labeling element that is difficult to counterfeit and that can be confirmed by visual inspection or using a device may be attached. .

As such a labeling element, one using a hologram is known as described in Patent Document 1. The hologram has features such as displaying an interference color that cannot be reproduced or difficult with a copy, realizing high designability, and being difficult to manufacture. Therefore, holograms are widely used for the purpose of preventing forgery.
JP-A-11-277962

  However, with the popularization of hologram manufacturing technology in recent years, it is becoming possible to forge a label element having a simple configuration using a hologram.

  Then, an object of this invention is to provide the forgery prevention technique which can achieve the high anti-counterfeit effect.

  According to the first aspect of the present invention, there is provided a selective element that is attached to an article and used to confirm that the article is genuine. The selective reflection that generates selective reflection when irradiated with white light as natural light. The labeling element includes a transmission region through which an object located on the back side of the labeling element can be seen when viewed from the front side of the labeling element, and at least a part of the transmission region is the There is provided a marker element characterized in that selective reflection occurs when white light as natural light is irradiated from the front side or the back side.

  According to a second aspect of the present invention, an article to be confirmed to be authentic and a labeling element according to the first side, wherein the article and the labeling element include the transmission region on the front side and the labeling element. Provided is a labeled article characterized in that it is integrated so that it can be observed from both sides on the back side.

  According to a third aspect of the present invention, there is provided a method for discriminating between a genuine product and a non-genuine product as an object that is unknown whether it is a genuine product, wherein the genuine product is a labeled product according to the second aspect. Yes, when the object is viewed from the front side, an object positioned on the back side can be seen through, and light is irradiated from the front side when irradiated from the front side and light is irradiated from the front side. And determining that the target article is a non-genuine product when it does not include a labeling element including a transmissive region that displays a color different from that observed from the back side. Is provided.

  According to the present invention, a forgery prevention technique capable of achieving a high forgery prevention effect is provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that, throughout all the drawings, the same reference numerals are given to components that exhibit the same or similar functions, and redundant descriptions are omitted.

  FIG. 1 is a plan view schematically showing a marker element according to one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II of the labeling element shown in FIG.

  One of the two main surfaces of the labeling element 10 is a “front surface” and the other is a “back surface”. In the following description, a surface of the labeling element 10 on which a printing layer 112 described later is provided is referred to as a “front surface”, and a surface on the opposite side is referred to as a “back surface”.

  The labeling element 10 shown in FIGS. 1 and 2 is, for example, a tag attached to an article to be confirmed to be genuine. If a labeled article formed by attaching the labeling element 10 to this article is regarded as a genuine product, an article whose unknown whether or not it is genuine is a non-authentic product such as a counterfeit product or a counterfeit product if the labeling device is not attached. It can be judged that it is a product. In addition, as will be described in detail later, even if a labeling element is attached to an article whose authenticity is unknown, the labeling element is not the same as the labeling element 10 shown in FIGS. In this case, it can be determined that the article is non-genuine.

The labeling element 10 includes a support 11 and a cholesteric liquid crystal layer 12.
The support 11 has a plate shape and includes a printing substrate 111, a printing layer 112, and a light transmission portion 113. In FIG. 2, the print layer 112 is omitted.

  The printing substrate 111 is a light shielding layer for forming the printing layer 112. The substrate 111 may have a single layer structure or a multilayer structure. The substrate 111 is made of, for example, plastic, glass, paper, metal, or a composite material thereof. The substrate 111 can be omitted.

The support body 111 is provided with two through holes.
One through-hole is used to support the identification element 10 on an article to be confirmed to be genuine. For example, the identification element 10 is integrated with a fastener such as a string using the through hole, and the fastener is integrated with an article to be confirmed to be genuine. This through hole can be omitted.

A light transmission portion 113 is installed in the other through hole. In the identification element 10 shown in FIGS. 1 and 2, a portion corresponding to the through hole corresponds to the transmission region _RT . The “transmission area” is an area through which an object located on the back side can be seen through when the identification element 10 is observed from the front side.

  The print layer 112 is formed on the base material 111. The print layer 112 displays images such as characters and graphics. The print layer 112 may be formed on both surfaces of the substrate 111. The printed layer 112 is formed on the substrate 111 if at least a part of the object located on the back side can be seen through when the region corresponding to the light transmitting portion 113 of the marker element 10 is observed from the front side. Instead, it may be formed on the light transmission portion 113 and / or the cholesteric liquid crystal layer 12, or may be formed on the substrate 111 and the light transmission portion 113 and / or the cholesteric liquid crystal layer 12. The printing layer 112 can be omitted.

  The light transmitting portion 113 serves as a window that allows the transmitted light to be observed from the back side when the cholesteric liquid crystal layer 12 is irradiated with light from the front side. In addition, the light transmission portion 113 plays a role as a base for forming the cholesteric liquid crystal layer 12 and / or a protective layer for protecting the cholesteric liquid crystal layer 12, for example.

  The light transmission portion 113 is typically transparent. The light transmission part 113 may have a single layer structure or a multilayer structure. Examples of the material of the light transmitting portion 113 include acrylic, urethane, epoxy, vinyl chloride, styrene, cellulose, polyacetate, polyamide, polyimide, polyolefin, polycarbonate, polystyrene, poly, Transparent resins such as ether, polyester, phenol or melamine resins, transparent inorganic materials such as glass or quartz, or combinations thereof can be used. The light transmitting portion 113 can be omitted.

  The cholesteric liquid crystal layer 12 is located in a through hole provided in the substrate 111 and faces the light transmission portion 113. Typically, the cholesteric liquid crystal layer 12 is formed on the light transmission portion 113.

  The cholesteric liquid crystal layer 12 is a layer having selective reflectivity and circular polarization selectivity. The selective reflectivity and the circularly polarized light selectivity will be described in detail later.

  The cholesteric liquid crystal layer 12 includes a mesogenic group exhibiting a cholesteric phase. The average helical axis of the helical structure formed by the mesogenic group is substantially perpendicular to the film surface. Here, the “cholesteric phase” is used only for explaining the arrangement of mesogenic groups, and thus does not refer to the presence or absence of fluidity.

  The cholesteric liquid crystal layer 12 is made of, for example, a solid polymer material in which a mesogenic group exhibits a cholesteric phase. Alternatively, the cholesteric liquid crystal layer 12 is made of a composite material including a transparent matrix such as a transparent resin and particles made of a cholesteric liquid crystal material dispersed therein.

  The cholesteric liquid crystal layer 12 made of a solid polymer material is obtained, for example, by cross-linking a low-molecular liquid crystal material exhibiting a cholesteric phase by photoreaction or thermal reaction and fixing the arrangement of those mesogenic groups. . Alternatively, the cholesteric liquid crystal layer 12 may be prepared by cooling the side chain or main chain type thermotropic polymer liquid crystal material in which the mesogenic group exhibits a cholesteric phase to a temperature not higher than the glass transition point, thereby aligning the mesogenic group. Obtained by immobilization. Alternatively, the previous cholesteric liquid crystal layer 12 gradually removes the solvent from the liquid containing the solvent and the side chain type or main chain type lyotropic polymer liquid crystal material in which the mesogenic group exhibits a cholesteric phase, It is obtained by immobilizing the sequence of mesogenic groups.

  Examples of the polymer material in which the mesogenic group exhibits a cholesteric phase include, for example, polyacrylate, polymethacrylate, polysiloxane, and polymalonate having a mesogenic group in the side chain, or a polyester having a mesogenic group in the main chain, Main chain polymers such as polyester amides, polycarbonates, polyamides and polyimides can be used.

Here, the selective reflectivity and circular polarization selectivity exhibited by the cholesteric phase will be described.
In the layer in which the mesogenic group exhibits a cholesteric phase, the monomolecular layer in which the mesogenic group is aligned in the same direction is stacked so as to form a helical structure having a helical axis in which the orientation direction of the mesogenic group is parallel to the thickness direction. Is a layer. Such a layer, when irradiated with white light parallel to the helix axis, has circularly polarized light having a wavelength λ substantially equal to the helix pitch P and the rotation direction of the polarization plane equal to the helix direction of the helix. Compared with the circularly polarized light of the same wavelength whose directions are opposite to each other, and the right circularly polarized light and the left circularly polarized light of other wavelengths, it reflects strongly. That is, the above layer exhibits selective reflectivity and circular polarization selectivity.

The selective reflectivity will be described in detail.
Selective reflectivity refers to the property of strongly reflecting light in a specific wavelength band of incident light as compared to light in other wavelength bands. Using this property, as is apparent from the following equations (1) and (2), for example, by appropriately selecting the helical pitch P, the reflected light has high color purity and has a desired center wavelength. It can be colored.

λ _s = n _m × P (1)
Δλ = Δn × P / n _m (2)
Here, λ _s and Δλ indicate the center wavelength and bandwidth of the selective reflection wavelength band, respectively. Δn represents the difference between n _e -n _o the extraordinary refractive index n _e and ordinary index n _o of a layer having a selective reflection property. _nm represents the average refractive index [(n _o ² + _ne ² ) / 2] ^1/2 of the layer having selective reflectivity.

Equations (1) and (2) give the center wavelength λ _s and the bandwidth Δλ of the selective reflection wavelength band when light is irradiated parallel to the helical axis. When light is irradiated parallel to the spiral axis, the spiral pitch P apparently decreases. Therefore, the center wavelength λ _s shifts to the short wavelength side, and the bandwidth Δλ decreases. Therefore, as the angle formed by the observation direction and the spiral axis is increased, the wavelength of the display light is shifted to the short wavelength side and the color purity thereof is increased.

Next, circular polarization selectivity will be described in detail.
The circularly polarized light selectivity is a property in which one of the right circularly polarized light and the left circularly polarized light is transmitted with a higher transmittance and the other circularly polarized light is reflected with a higher reflectance. For example, in the case of a cholesteric phase in which the twist direction of the spiral is clockwise, left circularly polarized light is transmitted with higher transmittance among right circularly polarized light and left circularly polarized light, and right circularly polarized light is reflected with higher reflectance. Note that the reflection caused by the cholesteric phase reflects right-handed circularly polarized light or left-handed circularly polarized light without reversing the twist direction of the spiral, unlike normal reflection. That is, when the right circularly polarized light is incident on the cholesteric phase having a clockwise twist direction, the reflected light is ideally right circularly polarized light.

  The helical pitch P of the mesogenic group in the cholesteric liquid crystal layer 12 is, for example, in the visible region of about 380 nm to about 780 nm, and typically in the range of about 400 nm to about 700 nm where the selective reflection light is easily recognized visually. To do. When using a photodetector for authenticity determination, the helical pitch P may not be in the visible region.

Next, an image displayed by the marker element 10 will be described.
FIG. 3 is a diagram schematically showing an example of a method for observing an image displayed by the marker element shown in FIGS. 1 and 2. FIG. 4 is a diagram schematically illustrating another example of a method for observing an image displayed by the marker element illustrated in FIGS. 1 and 2. 3 and 4, LS indicates a light source, and OS indicates an observer. Further, L _I, L _R and L _T respectively show the illumination light, reflected light and transmitted light.

FIG. 3 shows a state in which an image displayed by the marker element 10 is observed from the rear side when the front surface of the marker element 10 is illuminated. FIG. 4 shows a state in which an image displayed by the marker element 10 is observed from the front side when the front surface of the marker element 10 is illuminated. 3 and 4, the light source LS emits the illumination light L _I in the normal direction of the identification element 10, and the observer OS observes the marker element 10 from the normal direction.

As an example, it is assumed that the illumination light L _I is white light and the mesogenic group in the cholesteric liquid crystal layer 12 exhibits a cholesteric phase in which the helical twist direction is clockwise. For simplification, it is assumed that the efficiency of selective reflection is 100%.

In this case, as is clear from the above description regarding selective reflectivity and circular polarization selectivity, the transmission region _RT composed of the cholesteric liquid crystal layer 12 and the light transmission portion 113 has a helical pitch of the spiral formed by the mesogenic group. Only right circular polarized light having a wavelength substantially equal to P is reflected, and only left circular polarized light having a wavelength substantially equal to the helical pitch P, and right circular polarized light and left circular polarized light of other wavelengths are transmitted. That is, the reflected light L _R is the right circularly polarized light having a wavelength approximately equal the helical pitch P, the transmitted light L _T is right circularly polarized light and left circularly polarized light and other wavelengths having a wavelength substantially equal to the helical pitch P Left circularly polarized light.

Therefore, when the identification element 10 is observed as shown in FIG. 3, the transmission region _RT is substantially the same as white light except that the intensity of the light component having a wavelength substantially equal to the helical pitch P is weakened. A color corresponding to light having a spectrum is displayed. Then, when the identification element 10 is observed as shown in FIG. 4, the transmission region _RT displays a color corresponding to a light component having a wavelength substantially equal to the spiral pitch P. For example, if the spiral pitch P is within the wavelength range of red light, the transmission region _RT displays a color in which red is weakened compared to white when the identification element 10 is observed as shown in FIG. When the identification element 10 is observed as shown in FIG. 4, red is displayed.

As described above, the transmissive region _RT displays different colors when the identification element 10 is observed by the method shown in FIG. 3 and when the identification element 10 is observed by the method shown in FIG. Therefore, for example, even if the appearance of a certain marker element is the same as or similar to the marker element 10 shown in FIGS. 1 and 2, the display color of the marker element is observed by the method described with reference to FIGS. By confirming the change, it is possible to determine whether or not the labeling element has the structure described with reference to FIGS. That is, when a certain marker element does not cause the above-described color change, it can be understood that the marker element does not have the structure described with reference to FIGS.

Further, the transmission region R _T is the same as that shown in FIG. 3 when the marker element 10 is turned over so that the cholesteric liquid crystal layer 12 faces the observer OS and the light transmission portion 113 faces the light source LS. The same color as described with reference to FIG. The transmission region R _T is also the case where the label element 10 is turned over from the state shown in FIG. 4, the cholesteric liquid crystal layer 12 is opposed to the observer OS, and the light transmission portion 113 is opposed to the light source LS. The same color as described with reference to FIG. In other words, the transmissive region _RT includes the case where the front surface of the marker element 10 is the observation surface and the marker element unless the relative positions of the light source LS, the observer OS, and the transmissive region _RT and the normal direction of the marker element 10 are changed. The same color is displayed when the back surface of 10 is the observation surface.

Thus, the image displayed by the transmissive region _RT has a characteristic color change. Therefore, if a labeled article formed by attaching the labeling element 10 to an article is a genuine article, even if the labeling element is attached to an article whose identity is unknown, If it does not have at least one of the features described above, it can be determined that the article is non-genuine.

  The features described above are impossible or difficult to reproduce using other techniques. Therefore, the labeling element 10 achieves a high anti-counterfeit effect even though no hologram is used.

  Further, the above-described change in display color can be confirmed without using a special device. That is, for example, authenticity can be determined by observing the labeling element with the naked eye without using a polarizer or a special light source.

  Furthermore, the change in display color described above can be converted into an electrical signal using a photodetector. Therefore, the above-described authenticity determination is easy to mechanize.

For authenticity determination, a polarizer may be used. For example, when observing the labeling element 10 as shown in FIGS. 3 and 4, the labeling element 10 and the right circularly polarizing plate are arranged so that the quarter-wave plate of the right circularly polarizing plate faces the labeling element 10 and the right circle. The linear polarizer of the polarizing plate is overlaid so as to face the light source LS. In this case, if the right circular polarizer is designed to convert natural light having a wavelength equal to the spiral pitch P into right circular polarized light, the reflected light L _R is the same as when the right circular polarizer is not used. contrast is the right circularly polarized light of wavelength substantially equal to the helical pitch P, the transmitted light L _T, unlike the case of not using the right circular photons, right right circularly polarized light and the previous different wavelength than the helical pitch P This is left circularly polarized light in a wavelength band that is not converted to right circularly polarized light by the circular polarizer. That is, by using a right circular photons, a light component of the transmitted light L _T, light having a wavelength approximately equal the helical pitch P can be prevented or reduced from being emitted. Thus, the color displayed by the transmissive region R _T in the condition to observe the transmission light L _T, the difference between the color to be displayed is the transmission region R _T in the condition to observe the reflected light L _R, it can be increased.

Various modifications can be made to the marker element 10 described above.
Although the labeling element 10 shown in FIGS. 1 and 2 does not use a hologram, the labeling element 10 may further include a hologram. For example, the transmission region _RT may further include a hologram. In this case, a better anti-counterfeit effect can be achieved.

  The marker element 10 may further include a protective layer on at least one main surface. By providing the protective layer, the durability of the label element 10 can be improved. Examples of the material for the protective layer include acrylic resin, urethane resin, epoxy resin, silicon resin, ethylene vinyl alcohol copolymer resin, polyamide resin, polyester resin, polystyrene resin, or cellulose resin. Can be used.

  In the marker element 10, a plurality of cholesteric liquid crystal layers 12 having different spiral twist directions and / or spiral pitches P may be stacked. That is, a single layer structure or a multilayer structure may be employed for the layer that causes selective reflection.

When a multilayer structure composed of a plurality of cholesteric liquid crystal layers 12 having different spiral pitches P is employed, a more complicated color can be displayed in the transmission region _RT as compared with the case where a single layer structure is employed.

  In addition, when a multi-layer structure composed of cholesteric liquid crystal layers 12 having the same spiral pitch P and different twist directions of the spiral is adopted, the display colors can be made equal when irradiated with right circularly polarized light and when irradiated with left circularly polarized light. The display colors can be made substantially equal when irradiated with right or left circularly polarized light and when irradiated with natural light.

And when the multilayer structure formed by laminating a plurality of cholesteric liquid crystal layers 12 having different spiral directions and spiral pitches P is used, compared with the case where a single layer structure is adopted when natural light is irradiated. In addition to being able to display complex colors in the transmission region _RT , it is possible to make display colors different between natural light irradiation, right circular polarized light irradiation, and left circular polarized light irradiation.

  Instead of laminating a plurality of cholesteric liquid crystal layers 12 having different helical twist directions and / or helical pitches P, a structure in which the cholesteric liquid crystal layers 12 are arranged in the same plane may be adopted. Alternatively, a structure in which a plurality of cholesteric liquid crystal layers 12 having different helical twist directions and / or helical pitches P are partially overlapped may be employed. By carrying out like this, the further outstanding design property can be achieved.

The portion other than the cholesteric liquid crystal layer 12 in the transmission region _RT , here, the light transmission portion 113 may be optically isotropic or may be optically anisotropic. When the portion other than the cholesteric liquid crystal layer 12 in the transmissive region _RT is optically isotropic, the previous portion does not affect the bias of the circularly polarized light emitted from the cholesteric liquid crystal layer 12. Therefore, for example, when the circularly polarizing plate and the labeling element 10 are overlapped and the selectively reflected light from the labeling element 10 is observed, even if the circularly polarizing plate is rotated around its normal line, the brightness of the image is reduced. No change will occur. Further, when the portion other than the cholesteric liquid crystal layer 12 in the transmission region _RT has birefringence, for example, the circularly polarizing plate is used in the state where the circularly polarizing plate and the labeling element 10 are overlapped. Observing the selectively reflected light from the marker element 10 while rotating around the line can cause a change in brightness in the image.

The transmission region _RT may further include a colored layer.
FIG. 5 is a plan view schematically showing a modification of the marker element shown in FIGS. 1 and 2. 6 is a cross-sectional view taken along line VI-VI of the labeling element shown in FIG.

  The labeling element 10 shown in FIGS. 5 and 6 has the same structure as the labeling element 10 described with reference to FIGS. 1 and 2 except that the following configuration is adopted. That is, in the marker element 10 shown in FIGS. 5 and 6, the cholesteric liquid crystal layer 12 does not cover the entire surface of the light transmission portion 113 but covers only a part thereof. Here, the cholesteric liquid crystal layer 12 has an “I” -shaped pattern. The label element 10 further includes a colored layer 13.

  The colored layer 13 covers the cholesteric liquid crystal layer 12 and the light transmission portion 113 and has light transmittance. The colored layer 13 includes, for example, a transparent resin and a pigment dispersed therein. The colored layer 13 may be provided on the surface opposite to the surface on which the cholesteric liquid crystal layer 12 is provided, out of both main surfaces of the light transmitting portion 113. Alternatively, the function of the colored layer 13 may be provided to the light transmitting portion 113 instead of providing the colored layer 13. In this case, for example, colored glass colored with a transition metal ion or a metal colloid can be used as the light transmitting portion 113.

  The colored layer 13 is useful for improving design properties, for example. In addition, when the colored layer 13 is provided, it is possible to obtain a better anti-counterfeit effect as described below.

First, an image displayed by the transmission region _RT when the absorption wavelength band in the visible region of the colored layer 13 includes the selective reflection wavelength band of the cholesteric liquid crystal layer 12 will be described. Here, the arrangement shown in FIGS. 3 and 4 is adopted except that the identification element 10 shown in FIGS. 5 and 6 is used. Here, the illumination light L _I is white light, and the light transmission portion 113 faces the light source LS.

  In the present specification, the “transmission wavelength band” refers to the atmosphere other than the absorption wavelength band in the visible region.

  FIG. 7 is a plan view schematically showing an example of an image that can be displayed under the condition that the transmission region of the identification element shown in FIGS. 5 and 6 observes transmitted light. FIG. 8 is a plan view schematically showing an example of an image that can be displayed under the condition that the transmission region of the identification element shown in FIGS. 5 and 6 observes the reflected light.

For example, the colored layer 13 transmits blue-green light when irradiated with white light. In the cholesteric liquid crystal layer 12, the spiral direction of the spiral formed by the mesogenic group is clockwise, and the spiral pitch P is red. It is assumed that it is equal to the wavelength of light. In this case, when the transmitted light is observed as shown in FIG. 3, the portion corresponding to the cholesteric liquid crystal layer 12 in the transmissive region _RT and the other portions are irradiated with natural light L _{I as} shown in FIG. 7. In either right circular polarization or left circular polarization, blue-green is displayed. On the other hand, when the reflected light is observed as shown in FIG. 4, the portion corresponding to the cholesteric liquid crystal layer 12 in the transmissive region R _T shows that when the illumination light L _I is natural light or right circularly polarized light as shown in FIG. Compared with other parts, light blue-green is displayed, and when the illumination light L _I is left circularly polarized light, the same blue-green as the other parts is displayed as shown in FIG.

Next, an image displayed by the transmission region _RT when the colored layer 13 transmits only light in the selective reflection wavelength band in the visible region will be described. Here, the arrangement shown in FIGS. 3 and 4 is adopted except that the identification element 10 shown in FIGS. 5 and 6 is used. Here, the illumination light L _I is white light, and the light transmission portion 113 faces the light source LS.

  For example, the colored layer 13 transmits red light when irradiated with white light. In the cholesteric liquid crystal layer 12, the spiral direction of the spiral formed by the mesogenic group is clockwise, and the spiral pitch P is red light. Is equal to the wavelength of.

In this case, when the transmitted light is observed as shown in FIG. 3, the portion corresponding to the cholesteric liquid crystal layer 12 in the transmission region _RT displays black when the illumination light L _I is right circularly polarized light, and the illumination light L _{When I} is left circularly polarized light or white light, red is displayed. In addition, the other part of the transmission region _RT displays red regardless of whether the illumination light L _I is natural light, right circularly polarized light, or left circularly polarized light. That is, in this case, the cholesteric liquid crystal layer 12 portion corresponding to the other portions of the transmissive region R _T, and displays a different color from each other when the illumination light L _I is the right circularly polarized light, the illumination light L _I is When it is natural light or left circularly polarized light, the same color is displayed.

On the other hand, when the reflected light is observed as shown in FIG. 4, the illumination light L _I is natural light, right circularly polarized light, and left circularly polarized light in the portion corresponding to the cholesteric liquid crystal layer 12 in the transmission region _RT and the other portions. In either case, red is displayed. That is, in this case, the portion corresponding to the cholesteric liquid crystal layer 12 in the transmission region _RT and the other portion have the same color regardless of whether the illumination light L _I is natural light, right circular polarization, or left circular polarization. Is displayed.

Thus, when the colored layer 13 is provided, a more complicated display is possible as compared with the case where the colored layer 13 is not provided. In addition, when the colored layer 13 is provided, the absorption wavelength band of the colored layer 13 includes the selective reflection wavelength band of the cholesteric liquid crystal layer 12, and only the light in the selective reflection wavelength band of the colored layer 13 within the visible region. In both cases, a latent image to be visualized can be formed by observing with a circular polarizer at a portion corresponding to the cholesteric liquid crystal layer 12 in the transmissive region _RT and other portions. .

Here, an image displayed by the transmission region _RT when observed from the normal direction is described. When the observation direction is tilted, the selective reflection wavelength band of the cholesteric liquid crystal layer 12 changes. Therefore, the display color of the portion corresponding to the cholesteric liquid crystal layer 12 in the transmissive region _RT may also change.

In the case where substantially the same color is displayed in the portion corresponding to the cholesteric liquid crystal layer 12 in the transmissive region _RT and the other portion, the color difference on the u′v ′ chromaticity diagram is set within 0.015, for example. Typically, it is within 0.01. This can prevent or make it difficult for the observer to perceive the difference in display colors.

  Although the identification element 10 shown in FIGS. 5 and 6 includes only one colored layer 13, the identification element 10 may include a plurality of colored layers 13 having different transmission wavelength bands or absorption wavelength bands. When a structure in which a plurality of colored layers 13 having different transmission wavelength bands or absorption wavelength bands are arranged in the same plane or a partially overlapped structure is adopted, a further excellent design can be achieved.

  The structure described with respect to the labeling element 10 can also be applied to labeling elements other than tags. For example, the structure described above may be employed for adhesive labels, transfer foils, and the like.

Next, a labeled article including the above-described labeling element 10 will be described.
FIG. 9 is a plan view schematically showing an example of a labeled article. FIG. 10 is a cross-sectional view along the line XX of the labeled article shown in FIG.

  9 and 10 illustrate a magnetic card 1 as an example of a labeled article. The magnetic card 1 includes a labeling element 10, a base material 20, a printed layer 30, a magnetic recording layer 40, and an adhesive layer 50. The base material 20 includes a card body 201 and a light transmission layer 202. The card body 201 and the light transmission layer 202 are made of plastic, for example. The card body 201 is provided with a through hole, and the light transmission layer 202 is fitted into the through hole provided in the card body 201. The print layer 30 and the magnetic recording layer 40 are provided on the card body 201.

  The labeling element 10 is affixed to a portion corresponding to the light transmission layer 202 of the substrate 20 through the adhesive layer 50. Thereby, the image displayed by the marker element 10 can be seen both when the magnetic card 1 is observed from the front side and when observed from the back side.

  The magnetic card 1 includes the labeling element 10 described above. Therefore, forgery or imitation of the magnetic card 1 is difficult. Further, since the magnetic card 1 includes the labeling element 10, it is easy to discriminate between an authentic product and a non-authentic product if it is unknown whether it is an authentic product. In addition, since the magnetic card 1 further includes the printing layer 30 and the magnetic recording layer 40 in addition to the labeling element 10, it is possible to adopt measures for preventing forgery using them.

  9 and 10 exemplify a magnetic card as a labeling article including the labeling element 10, the labeling article including the labeling element 10 is not limited to this. For example, the labeled article including the labeling element 10 may be other cards such as an IC (integrated circuit) card, a wireless card, and an ID (identification) card. Alternatively, the labeled article including the labeling element 10 may be securities such as gift certificates and stock certificates. Alternatively, the labeled article including the labeling element 10 may be a bill, a deposit, or a savings passbook. Thus, the labeling element 10 can be applied to various printed materials.

Moreover, in FIG.9 and FIG.10, although the labeling element 10 is affixed on the base material 20, the labeling element 10 can be supported on a base material by another method. For example, when paper is used as the base material, the labeling element 10 may be inserted into the paper, and the paper may be opened at a position corresponding to the transmission region _RT of the labeling element 10.

  The labeling element 10 may be supported by other methods on an article to be confirmed to be genuine. For example, a tag may be constituted by the labeling element 10, and this may be supported on an article to be confirmed to be genuine through a fastener such as a string, a chain, and a metal ring.

  In addition, the labeled article may not be a printed material. That is, the labeling element 10 may be supported on an article that does not include a printed layer. For example, the labeling element 10 may be supported by a luxury item such as a work of art.

  The labeling article may not include the labeling element 10 that can be handled by itself. That is, the labeling article may form the constituent elements of the labeling element 10 on the article to be confirmed to be genuine.

It is a top view which shows roughly the marker element which concerns on 1 aspect of this invention. Sectional drawing along the II-II line of the labeling element shown in FIG. The figure which shows schematically an example of the method of observing the image which the marker element shown in FIG.1 and FIG.2 displays. The figure which shows schematically the other example of the method of observing the image which the marker element shown in FIG.1 and FIG.2 displays. The top view which shows roughly the modification of the label | marker element shown in FIG.1 and FIG.2. Sectional drawing along the VI-VI line of the label | marker element shown in FIG. FIG. 7 is a plan view schematically showing an example of an image that can be displayed under the condition that the transmission region of the identification element shown in FIGS. 5 and 6 observes transmitted light. FIG. 7 is a plan view schematically showing an example of an image that can be displayed under a condition in which a transmission region of the identification element shown in FIGS. 5 and 6 observes reflected light. The top view which shows an example of a labeled article schematically. Sectional drawing along the XX line of the labeled article shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Card, 10 ... Labeling element, 11 ... Support body, 12 ... Cholesteric liquid crystal layer, 13 ... Colored layer, 20 ... Base material, 30 ... Printing layer, 40 ... Magnetic recording layer, 50 ... Adhesive layer, 111 ... Base material , 112... Print layer, 113... Light transmission part, 201... Card body, 202.

Claims (14)

  A labeling element that is attached to an article and used to confirm that the article is genuine, and includes a selective reflection layer that generates selective reflection when irradiated with white light as natural light. When this is observed from the front side of the labeling element, it includes a transmission region through which an object located on the back side of the labeling element can be seen, and at least part of the transmission region is natural light from the front side or the back side. A labeling element that produces selective reflection when irradiated with white light.   2. The labeling element according to claim 1, further comprising a colored layer having light transmittance and facing the selective reflection layer.   The labeling element according to claim 2, wherein the selective reflection layer faces only a part of the colored layer.   4. The labeling element according to claim 2, wherein a wavelength band of light selectively reflected by the selective reflection layer in a normal direction thereof is within an absorption wavelength band of the colored layer.   The transmission wavelength band in the visible region of the colored layer includes a wavelength band of light selectively reflected by the selective reflection layer in the normal direction or only a part thereof. Marking element.   The colored layer further includes another colored layer having a transmission wavelength band different from that of the colored layer, the other colored layer faces the selective reflection layer, and the colored layers do not overlap each other. The labeling element according to any one of claims 2 to 5, further comprising a portion.   The selective reflection layer includes a first cholesteric liquid crystal layer in which the helical twist direction is clockwise and a second cholesteric liquid crystal layer in which the helical twist direction is counterclockwise, and each of the first and second cholesteric liquid crystal layers includes The labeling element according to any one of claims 1 to 6, comprising a non-overlapping portion.   8. The labeling device according to claim 7, wherein the first and second cholesteric liquid crystal layers have the same helical pitch.   The labeling element according to any one of claims 1 to 5, wherein the selective reflection layer includes a plurality of cholesteric liquid crystal layers having different helical pitches.   The sign element according to any one of claims 1 to 9, wherein the transmission region includes a hologram.   The labeling element according to any one of claims 1 to 10, wherein a portion other than the selective reflection layer in the transmissive region is optically isotropic.   The labeling element according to any one of claims 1 to 11, wherein the labeling element is a tag.   An article to be confirmed to be a genuine product, and the labeling element according to any one of claims 1 to 12, wherein the article and the labeling element have the transmissive region at the front side and the back side. A labeled article characterized by being integrated so that it can be observed from both sides. A method for discriminating between a genuine product and a non-genuine product for an object whose identity is unknown.
The genuine product is a labeled article according to claim 13,
When the object is viewed from the front side, an object positioned on the back side can be seen through, and when the object is observed from the front side by irradiating light from the front side, and from the front side by irradiating light from the front side A method comprising determining that the target article is a non-genuine product when a labeling element including a transmissive region displaying a color different from that observed from the side is not provided.

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