JP5169463B2 - Security devices and labeled items - Google Patents

Description

  The present invention relates to a forgery prevention technique.

  In order to prevent forgery, a liquid crystal material may be used. For example, Patent Document 1 describes a security device including a birefringent layer made of a solidified cholesteric liquid crystal material. Patent Document 2 describes a security device including a birefringent layer made of a solidified nematic liquid crystal material.

  The anti-counterfeit technology using the solidified liquid crystal material is excellent in the effect of preventing forgery. In addition, a security device to which this forgery prevention technology is applied can achieve high identification and design.

However, the present inventors have found that there is room for improvement in this forgery prevention technology when inventing the present invention.
Japanese Patent Laid-Open No. 11-42875 JP 2003-251643 A

  An object of the present invention is to remove a birefringent layer made of a solidified liquid crystal material or a laminate including the same from the article without causing destruction or deformation after the security device is attached to the article. Is to make it difficult.

According to the first aspect of the present invention, a base material, a plurality of openings arranged in a one-dimensional or two-dimensional manner, and one or more openings are formed of a solidified liquid crystal material supported on one main surface of the base material. A birefringent layer provided with at least one of a cut and a reflection that is interposed between the base material and the birefringent layer or faces the birefringent layer with the base material in between A security device , wherein the reflective layer is made of a mixture containing a light-transmitting resin and metal particles .

  According to a second aspect of the present invention, there is provided a labeled article comprising the security device according to the first aspect and an article supporting the security device.

  According to the present invention, after a security device is attached to an article, the birefringent layer made of a solidified liquid crystal material or a laminate including the same can be removed from the article without causing destruction or deformation thereof. It becomes difficult.

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

  FIG. 1 is a plan view schematically showing a security device according to the first aspect of the present invention. 2 is a cross-sectional view taken along line II-II of the security device shown in FIG.

  In FIG. 1, the security device 10 is observed from the display surface side. In FIGS. 1 and 2, directions parallel to the display surface and orthogonal to each other are defined as an X direction and a Y direction, and a direction perpendicular to the display surface is defined as a Z direction.

  The security device 10 shown in FIGS. 1 and 2 is an adhesive label that is supported on an article to be confirmed to be genuine. The security device 10 includes a base material 11, a protective layer 12, a birefringent layer 13, a reflective layer 14, an adhesive layer 15, and an intermediate layer 16. The front surface of the security device 10 is a surface on the protective layer 12 side.

  The substrate 11 is, for example, a film or sheet made of resin. As this resin, for example, polyethylene terephthalate (hereinafter referred to as “PET”), triacetyl cellulose (hereinafter referred to as “TAC”), polycarbonate, polyester, polyacetal, polystyrene, or epoxy resin can be used.

The material of the substrate 11 is advantageously PET or TAC.
A layer made of PET is excellent in mechanical strength, dimensional stability, solvent resistance and processability. Moreover, PET is relatively inexpensive.

  A layer made of TAC is more likely to cause brittle fracture than a layer made of other resin. Therefore, the security device 10 using TAC as the material of the base material 11 is liable to cause destruction of the base material 11 when it is illegally peeled from the article.

  The base material 11 may or may not have optical transparency. Moreover, the base material 11 may have a single layer structure, and may have a multilayer structure.

  When the base material 11 is thick, when the security device 10 is illegally peeled from the article, it is difficult to break. Therefore, if peeling is performed carefully, it can be peeled from the article without causing breakage of the security device 10. When the base material 11 is thinned, the security device 10 can be easily broken. For example, when the thickness of the base material 11 is 40 μm or less, it is possible to make it extremely difficult to peel the security device 10 from the article without causing the security device 10 to break.

  The reflective layer 14 covers the front surface of the substrate 11. The reflective layer 14 is a metal layer obtained by a vapor deposition method such as a vacuum evaporation method and a sputtering method, for example.

  A layer having a relief structure on the surface, that is, a relief layer may be interposed between the reflective layer 14 and the substrate 11. When a relief layer is provided, a diffractive structure such as a diffraction grating and a hologram or a light scattering structure can be formed on the surface of the reflective layer 14 facing the birefringent layer 13.

  As a material for the relief layer, for example, a resin can be used. Examples of this resin include acrylic resin, epoxy resin, vinyl chloride resin, styrene resin, cellulose resin, acetal resin, polyamide resin, polyimide resin, olefin resin, polycarbonate resin, polyether resin, polyester resin, phenol resin, or melamine resin. Can be used.

  Instead of using a metal layer as the reflective layer 14, a single-layer or multilayer dielectric layer may be used. In this case, the relief layer described above may or may not be interposed between the reflective layer 14 and the substrate 11. A multilayer dielectric layer, that is, a dielectric multilayer film is obtained by alternately depositing a high refractive index material such as zinc sulfide and a low refractive index material such as magnesium fluoride.

  Instead of using a metal layer as the reflective layer 14, a layer made of a mixture containing a light transmitting resin and metal particles may be used.

  Examples of the light transmissive resin include natural rubber, acrylic resin, polyolefin, polyether, epoxy resin, polyvinyl chloride, chloroprene rubber, silicone resin, nitrile rubber, phenol resin, polyamide, polyimide, polyurethane, polyvinyl acetate, polystyrene. , Polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl butyral, polybenzimidazole, methacrylic resin, melamine resin, melamine resin, resorcinol resin, or a mixture containing one or more thereof can be used.

  The metal particles are made of a metal or an alloy. As this metal or alloy, for example, aluminum, platinum, gold, silver, copper, titanium, bismuth, germanium, indium, tin, or an alloy containing one or more thereof can be used. Among these, aluminum has a high reflectance over the entire visible region, infrared region, and near-ultraviolet region. Moreover, aluminum is highly resistant to oxidation. Therefore, it is preferable to use aluminum particles as the metal particles.

  When irradiated with polarized light, the reflective layer 14 made of a mixture containing a light-transmitting resin and metal particles reflects this polarized light while substantially maintaining the polarization. That is, the reflective layer 14 can function in substantially the same manner as a metal layer obtained by a vapor deposition method such as a vacuum deposition method and a sputtering method.

  In addition, in this case, a higher interlayer adhesion strength can be achieved between adjacent layers as compared to the case where a metal layer is used as the reflective layer 14. That is, in this case, as compared with the case where a metal layer is used as the reflective layer 14, peeling at the interface between the reflective layer 14 and the adjacent layer can be made difficult to occur.

  In addition, metals such as aluminum are soluble in an alkaline solution. Therefore, when a metal layer is used as the reflective layer 14, the metal may be dissolved from the end face. On the other hand, when a layer made of a mixture containing a light transmitting resin and metal particles is used as the reflective layer 14, dissolution of the metal particles is prevented by the resin. That is, the reflective layer 14 made of a mixture containing a light transmissive resin and metal particles is unlikely to deteriorate.

  Moreover, the light scattering ability of the reflective layer 14 made of a mixture containing a light transmissive resin and metal particles changes when, for example, at least one of the particle size, shape, and content of the metal particles is changed.

  Instead of using a metal layer as the reflective layer 14, a layer made of a mixture containing the above light-transmitting resin and non-metal particles may be used. In this case, the interface between the base material 11 and the reflective layer 14 and / or the reflective layer 14 and the intermediate layer is used as in the case where a layer made of a mixture containing a light-transmitting resin and nonmetallic particles is used as the reflective layer 14. It is possible to make it difficult for peeling at the interface with 16 to occur. In this case, higher light scattering can be achieved as compared with the case where a layer made of a mixture containing a light-transmitting resin and metal particles is used as the reflective layer 14. As a material for the non-metallic particles, for example, an inorganic material such as silica or an organic material such as an acrylic resin can be used.

  The reflective layer 14 may cover the back surface of the substrate 11. In this case, the base material 11 is typically colorless and transparent or colored and transparent. In this case, the base material 11 may have birefringence, but preferably does not have birefringence so as not to affect the display.

  The reflective layer 14 may be omitted. However, when the reflective layer 14 is provided, an image that is superior in visibility can be displayed on the security device 10 as compared with the case where the reflective layer 14 is omitted.

  The intermediate layer 16 covers the front surface of the reflective layer 14. The intermediate layer 16 plays a role of improving the adhesion between the reflective layer 14 and the birefringent layer 13.

  The intermediate layer 16 is light transmissive. The intermediate layer 16 may be transparent or opaque. Further, the intermediate layer 16 may be colorless or colored. Typically, the intermediate layer 16 is colorless.

  Examples of the material of the intermediate layer 16 include acrylic resin, urethane resin, epoxy resin, vinyl chloride resin, styrene resin, cellulose resin, acetal resin, polyamide resin, polyimide resin, olefin resin, polycarbonate resin, polyether resin, polyester resin. Resins such as phenolic resins and melamine resins can be used. When such a material is used, a transparent intermediate layer 16 can be obtained.

  As a material for the intermediate layer 16, a mixture containing the above-described light-transmitting resin and metal particles for the reflective layer 14 may be used. When such a material is used, the intermediate layer 16 having light scattering properties can be obtained.

  The intermediate layer 16 can be omitted. For example, when the reflective layer 14 contains a resin, there is a possibility that the reflective layer 14 and the birefringent layer 13 can be bonded to each other with high strength without the intermediate layer 16.

  The birefringent layer 13 covers the front surface of the intermediate layer 16. The birefringent layer 13 is formed by solidifying a liquid crystal material. Typically, the birefringent layer 13 is a polymer birefringent layer formed by curing a polymerizable liquid crystal material having fluidity with ultraviolet rays or heat. This liquid crystal material is, for example, a nematic liquid crystal material.

  The front surface of the birefringent layer 13 includes regions Aa to Ac. Each of the areas Aa and Ab is circular. The region Ac surrounds the regions Aa and Ab. Each of the regions Aa to Ac may have other shapes.

  Hereinafter, portions of the security device 10 corresponding to the areas Aa to Ac are referred to as display units 100a to 100c, respectively. Further, portions of the birefringent layer 13 corresponding to the regions Aa to Ac are referred to as portions 130a to 130c, respectively.

  Each of the regions Aa and Ab is provided with a plurality of grooves that are aligned in the length direction and are adjacent to each other in a direction intersecting the length direction. The grooves provided in the region Aa and the grooves provided in the region Ab are different from each other in the length direction. Here, as an example, the length direction of the groove provided in the region Aa is parallel to the X direction, and the length direction of the groove provided in the region Ab is parallel to the Y direction.

  Various structures can be adopted for the regions Aa and Ab. For example, each of the regions Aa and Ab can employ a structure in which a plurality of grooves are arranged in parallel in the width direction at equal intervals.

  In each of the regions Aa and Ab, these grooves may not be parallel to each other. However, the closer these grooves are to be parallel, the easier it is for the long axes of the mesogens to be aligned in each of the portions 130a and 130b of the birefringent layer 13. The angle formed by these grooves is, for example, 5 ° or less, preferably 3 ° or less.

  In each of the regions Aa and Ab, these grooves may be arranged vertically and horizontally. The lengths of the grooves may be equal to each other or different from each other. Further, the distance between adjacent grooves in the length direction may be uniform or non-uniform. Furthermore, the distance between adjacent grooves in the width direction may be uniform or non-uniform.

  For example, in each of the areas Aa and Ab, grooves having the same length may be arranged vertically and horizontally. By making the grooves substantially parallel and appropriately setting the pitch, the diffraction grating can be constituted by these grooves.

  Alternatively, grooves of various lengths may be randomly arranged in each of the regions Aa and Ab. In this case, a unidirectional diffusion pattern can be formed with these grooves. Note that this unidirectional diffusion pattern has a larger light diffusion capacity in a plane perpendicular to the groove length direction than that in a plane parallel to the Z direction and the groove length direction. This is a pattern showing diffusion characteristics, that is, light scattering anisotropy. Here, as an example, it is assumed that the grooves provided in each of the regions Aa and Ab constitute a diffraction grating.

  The region Ac is a region where no groove is provided. The region Ac can be omitted.

  Of the birefringent layer 13, the portion 130a corresponding to the region Aa, the portion 130b corresponding to the region Ab, and the portion 130c corresponding to the region Ac have different mesogen alignment structures and / or alignment directions. . In the portion 130a of the birefringent layer 13 covering the region Aa, the orientation direction of the mesogen is substantially parallel to the length direction of the groove provided in the region Aa. In the portion 130b of the birefringent layer 13 covering the region Ab, the orientation direction of the mesogen is substantially parallel to the length direction of the groove provided in the region Ab. That is, in this example, the mesogen is oriented in the X direction in the portion 130a of the birefringent layer 13 that covers the region Aa. In the portion 130b of the birefringent layer 13 that covers the region Ab, the mesogen is oriented in the Y direction.

These portions 130a and 130b of the birefringent layer 13 are birefringent because the mesogens are oriented. Since the mesogen the birefringent portion 130a is oriented in the X direction, the refractive index for X-direction is the extraordinary ray refraction index n _e, the refractive index in the Y direction is the ordinary index n _o. Since the refractive index n _e is greater than the refractive index n _o, the slow axis of the birefringent portion 130a is parallel to the X direction, fast axis is parallel to the Y direction. The slow axis of the birefringent portion 130b is parallel to the Y direction, and the fast axis is parallel to the X direction.

  In the portion 130c of the birefringent layer 13 corresponding to the region Ac, the mesogen is typically not or ordered with a higher degree of order than the birefringent portions 130a and 130b. Here, as an example, it is assumed that the mesogen is not oriented in the portion 130c. That is, this portion 130c is assumed to be optically isotropic. In this portion 130c, for example, the surface used as a base when forming the portion 130c is subjected to an alignment treatment such as a rubbing treatment, whereby the mesogen can be oriented with a relatively high degree of order.

  The birefringent layer 13 can be formed by the following method, for example. First, a nematic liquid crystal material having photopolymerizability is applied on the underlayer. A relief structure corresponding to the relief structure provided on the front surface of the birefringent layer 13 is provided on the surface of the underlayer. The liquid crystal material is then irradiated with ultraviolet light to cause their polymerization. Thereby, the birefringent layer 13 in which the direction of the long axis of the mesogen is fixed is obtained. Thereafter, the underlayer is removed from the birefringent layer 13.

  However, when the protective layer 12 is used as the underlayer, the birefringent layer 13 may not be removed from the underlayer. Here, a nematic liquid crystal material is used as the material of the birefringent layer 13, but a cholesteric liquid crystal material or a smectic liquid crystal material may be used instead.

  The protective layer 12 covers the front surface of the birefringent layer 13. The protective layer 12 flattens the front surface of the security device 10. The protective layer 12 serves to protect the birefringent layer 13 from damage and deterioration, and also serves to prevent the relief structure provided on the front surface of the birefringent layer 13 from being illegally duplicated.

  The protective layer 12 is a light-transmitting layer and is typically transparent and optically isotropic. Protective layer 12 provides scattering to transmitted light and / or reflected light by emitting polarized transmitted light and reflected light when incident incident light having polarization is incident It may be. The protective layer 12 may be omitted.

  As the material of the protective layer 12, for example, a resin can be used. Examples of this resin include acrylic resin, epoxy resin, vinyl chloride resin, styrene resin, cellulose resin, acetal resin, polyamide resin, polyimide resin, olefin resin, polycarbonate resin, polyether resin, polyester resin, phenol resin, or melamine resin. Can be used.

  The adhesive layer 15 is provided on the back surface of the substrate 11. The adhesive layer 15 is used for attaching the security device 10 to an article. As a material for the adhesive layer 15, for example, a resin that can be used as a pressure-sensitive adhesive such as a pressure-sensitive adhesive can be used. The adhesive layer 15 can be omitted.

  In the security device 10, the birefringent layer 13 is provided with at least one of a plurality of openings and one or more cuts arranged one-dimensionally or two-dimensionally. Here, as an example, it is assumed that the security device 10 is provided with a plurality of openings (not shown) and a plurality of cuts NT arranged two-dimensionally in all layers except the adhesive layer 15. The security device 10 provided with at least one of these openings and cuts NT tends to break along the arrangement of openings and / or the cuts NT when attempting to peel from the article.

  When providing the cut NT, the number of the cut NT may be only one, but typically, a plurality of cuts NT are provided. When a plurality of cuts NT are provided, the cuts NT are arranged almost evenly. For example, in the polygonal security device 10, the cut NT is provided at each corner, or at each side, or at each corner and each side.

  When the cut NT is lengthened, the entire security device 10 or a part of the layer is easily broken along the cut NT when the security device 10 is to be peeled from the article. For example, when the opening is omitted and a cut NT having a length of 2 mm is provided, the security device 10 is broken as compared with the case where the opening is omitted and a cut NT having a length of 1 mm is provided. Without it occurring, it is difficult to peel it from the article. And when said opening is abbreviate | omitted and the cut | interruption NT whose length is 3 mm or more is provided, it will be very difficult to peel this from articles | goods, without producing the fracture | rupture of the security device 10. FIG.

  When a plurality of openings are provided, the openings are arranged so as to form a one-dimensional or two-dimensional array. For example, when the openings are arranged so as to form the cut NT and form a one-dimensional arrangement, if the cuts NT and the arrangement of the openings are arranged, the cuts NT and the arrangement of the openings are aligned. Breakage can occur. Further, if the openings are arranged so as to form a two-dimensional array, it is possible to cause a break regardless of the position and the length direction of the cut NT.

  The shape of the opening is arbitrary. For example, the shape of the opening may be a convex polygon such as a circle, an oval, an ellipse, a triangle and a parallelogram, or a concave polygon such as a star and a cross.

  If the dimension along the arrangement direction of the openings is small, it is difficult to cause breakage along the arrangement of the openings. On the other hand, if this dimension is large, the strength and optical characteristics of the security device 10 may be insufficient. The dimension along the arrangement direction of the openings is, for example, in the range of 10 μm to 100 μm.

  Moreover, when the distance between adjacent openings is long, breakage along the arrangement of the openings is difficult to occur. On the other hand, if this distance is short, the strength and optical characteristics of the security device 10 may be insufficient. The distance between adjacent openings is, for example, in the range of 10 μm to 70 μm.

  This security device 10 is obtained by the following method, for example.

  First, the birefringent layer 13 provided with a relief structure on one main surface is formed.

  For example, an underlayer having a relief structure on the surface is formed. This relief structure has a shape corresponding to the relief structure to be provided on the front surface of the birefringent layer 13. For example, when the relief structure to be provided on the front surface of the birefringent layer 13 is formed of a groove, an underlayer having linear protrusions provided on the surface is formed. Or when the relief structure which should be provided in the front surface of the birefringent layer 13 consists of a linear convex part, the base layer in which the groove | channel was provided in the surface is formed. Here, as an example, it is assumed that the relief structure to be provided on the front surface of the birefringent layer 13 is composed of linear protrusions.

  Next, the material of the birefringent layer 13 is applied on the main surface provided with the relief structure of the underlayer. As a material of the birefringent layer 13, for example, a polymerizable liquid crystal material having fluidity is used. In this coating film, in the region located above the groove provided on the surface of the underlayer, the mesogens of the liquid crystal material are aligned along the length direction of the groove.

  Thereafter, the coating film is cured by, for example, ultraviolet rays or heat while maintaining the orientation state of the mesogen. Thereby, the birefringent layer 13 is obtained.

  The underlayer can be formed, for example, on a photosensitive resin material by a method of recording a hologram pattern using a two-beam interference method or a method of drawing a pattern by an electron beam. Or you may form a base layer by pressing the metal mold | die which provided the fine linear convex part on resin like the manufacture of the surface relief type | mold hologram. For example, the underlayer is a method in which a thermoplastic resin layer is formed on a support layer (not shown), and an original plate provided with linear protrusions on its surface is pressed while applying heat, that is, heat embossing. Obtained by processing method. Alternatively, the base layer is coated with an ultraviolet curable resin on the support layer, and the ultraviolet curable resin is cured by, for example, irradiating ultraviolet rays from the support layer side while pressing the original plate against the resin layer, and then the original plate is removed. It can also be obtained by a method.

  Usually, a reverse plate is manufactured by transferring the concavo-convex structure of the original plate, and a duplicate plate is manufactured by transferring the concavo-convex structure of the reverse plate. Then, if necessary, a reversal plate is manufactured using the copy plate as an original plate, and the concavo-convex structure of the reverse plate is transferred to further manufacture a copy plate. In actual production, a copy obtained in this way is usually used.

  According to these methods, for example, a plurality of regions having different groove length directions, pitches, depths, widths, and lengths can be formed in one plane.

  The original plate can be obtained, for example, by performing electroforming of a mother die obtained by a method of recording a hologram pattern using a two-beam interference method, a method of drawing a pattern by an electron beam, or a method of cutting by a cutting tool. It is done. If a complicated structure is not used on the surface of the underlayer, grooves may be formed by rubbing.

  The depth of these grooves is, for example, in the range of 0.05 μm to 1 μm, and typically in the range of 0.1 μm to 1 μm. The length of the groove is, for example, in the range of 0.1 μm to 1 μm, and typically in the range of 0.5 μm to 1 μm. The pitch of the grooves is, for example, 0.1 μm or more, and typically 0.75 μm or more. The pitch of the grooves is, for example, 10 μm or less, and typically 2 μm or less. In order to orient mesogens with a high degree of order, it is advantageous that the pitch of the grooves is small.

  The area Aa and the area Ab may be further different in at least one of the pitch, width and depth or height of the grooves or linear protrusions provided in them. When at least one of the pitch, width and depth or height of the grooves or linear protrusions is further different between the area Aa and the area Ab, the area Aa and the area Ab are the grooves or The length directions of the linear protrusions may be equal. Alternatively, one of the areas Aa and Ab may be omitted.

  The underlayer is typically removed from the birefringent layer 13. The protective layer 12 is formed on the surface of the birefringent layer 13 from which the underlayer has been removed, that is, the main surface provided with the relief structure of the birefringent layer 13. The removal of the underlayer and the formation of the protective layer 12 may be performed at any stage where the security device 10 is manufactured. Alternatively, the underlayer itself may be used as the protective layer 12. That is, the base layer may not be removed.

  Next, the intermediate layer 16 and the reflective layer 14 are laminated in this order on the back surface of the surface on which the relief structure of the birefringent layer 13 is provided. And this laminated body is joined with one main surface of the base material 11, and the contact bonding layer 15 is formed on the other main surface of the base material 11. FIG. When the reflective layer 14 contains, for example, a thermoplastic resin, the previous laminate and the substrate 11 can be heat-sealed.

  Further, if necessary, the structure thus obtained is die cut. The security device 10 is completed as described above.

  After the security device 10 is attached to an article, it is difficult to remove the birefringent layer 13 or a laminate including the same from the article without causing breakage or deformation thereof. This will be described with reference to FIGS.

  FIG. 3 is a plan view schematically showing an example of a structure obtained when the security device shown in FIGS. 1 and 2 is attached to an article and peeled off. FIG. 4 is a plan view schematically showing another example of a structure obtained when the security device shown in FIGS. 1 and 2 is attached to an article and peeled off. FIG. 5 is a plan view schematically showing the birefringent layer before peeling. FIG. 6 is a plan view schematically showing the birefringent layer after peeling.

  3 and 4, the security device 10 is affixed to the article 30. When the security device 10 is to be peeled from the article 30, the entire security device 10 is broken along the cut NT as shown in FIG. 3, or some layers constituting the security device 10 are cut. Break along NT.

  The birefringent layer 13 is provided with a plurality of openings OP as shown in FIG. The birefringent layer 13 provided with the openings OP is easily broken along the arrangement of the openings OP when the security device 10 is peeled from the article 30. And even if the birefringent layer 13 provided with the opening OP is not broken, it tends to be elongated as compared with the case where the opening OP is not provided. When the birefringent layer 13 extends, its optical characteristics change. In particular, when the orientation direction of the mesogen is oblique with respect to the stretching direction, the birefringent layer 13 extends to change the direction of each of the slow axis and the fast axis. In addition, even if the birefringent layer 13 provided with the opening OP does not break, the shape of the opening OP changes.

  Therefore, it is difficult for the security device 10 to remove the birefringent layer 13 or the laminated body including the security device 10 from the article without causing breakage or deformation after the security device 10 is attached to the article.

  Next, an image that appears when the security device 10 is irradiated with white light and observed with the naked eye will be described. Here, as an example, the reflective layer 14 is made of a mixture containing a light-transmitting resin and metal particles, and has a light scattering property. In addition, it is assumed that the grooves provided in the regions Aa and Ab constitute a diffraction grating. White light is light composed of non-polarized light having all wavelengths in the visible region.

FIG. 7 is a plan view illustrating an example of an image displayed by the security device illustrated in FIGS. 1 and 2.
When the security device 10 is irradiated with white light from substantially the front direction and observed with the naked eye from the front, the display units 100a to 100c are impossible or difficult to distinguish from each other as shown in FIG. This will be described in more detail.

  White light as illumination light incident on the display unit 100a passes through the protective layer 12 shown in FIG. White light transmitted through the protective layer 12 enters the birefringent layer 12.

  The grooves provided in the region Aa constitute a diffraction grating. Accordingly, a part of these incident lights enters the birefringent portion 130a as diffracted light.

  The diffracted light that has passed through the birefringent portion 130 a passes through the intermediate layer 16 and is reflected by the reflective layer 14. Since the reflective layer 14 has light scattering properties, the reflected light is scattered light.

  The scattered light passes through the intermediate layer 16 and the birefringent portion 130a in this order. In the region Aa, a diffraction grating is provided. In addition to the reflected light from the reflective layer 14 being scattered light, the incident angle of illumination light varies in a normal environment. Therefore, the reflected light from the reflective layer 14 is transmitted through the protective layer 12 as scattered light. An observer perceives the scattered light as display light. Therefore, the display unit 100a looks silvery white.

  The display part 100b and the display part 100a differ only in the length direction of the groove | channel which comprises the diffraction grating except the planar shape. As is clear from the above description, when the display unit 100a is observed with the naked eye, the diffraction grating does not affect the display color or brightness. Therefore, the display unit 100b also looks silvery white.

  The display unit 100c is different from the display unit 100a only in that no groove is provided at the interface between the birefringent layer 13 and the protective layer 12 and the mesogens are not oriented except for the planar shape. . As is clear from the above description, when the display unit 100a is observed with the naked eye, the diffraction grating does not affect the display color or brightness. Therefore, the display unit 100c also looks silvery white.

  In this manner, the display units 100a to 100c appear silver white. The display units 100a to 100c have substantially the same brightness. Accordingly, when the security device 10 is irradiated with white light and observed with the naked eye from the front, the display units 100a to 100c are impossible or difficult to distinguish from each other as shown in FIG.

  When the security device 10 is irradiated with white light and observed with the naked eye, the display colors of the display units 100a to 100c remain silver white even when the observation angle is changed. Further, even if the security device 10 is rotated around the normal line while the observation angle is inclined, the display colors of the display units 100a to 100c remain silver white.

  Next, an image seen when the security device 10 is observed through a polarizer will be described. Here, as an example, a linearly polarizing film is used as the polarizer.

  FIG. 8 is a plan view schematically showing an example of an image that can be observed when the security device shown in FIGS. 1 and 2 and the linearly polarizing film are overlapped.

  In FIG. 8, when the security device 10 and the absorption linear polarizing film 50 shown in FIGS. 1 and 2 are viewed from the polarizing film 50 side, the transmission axis of the polarizing film 50 is in the X direction. In order to make an angle of 45 ° counterclockwise. When such an arrangement is adopted and this is observed from the front, as shown in FIG. 8, the display units 100a and 100b are easily discriminated from the display unit 100c and cannot be discriminated from each other. is there. This will be described in more detail.

  When the linearly polarizing film 50 is irradiated with white light as illumination light, the linearly polarizing film 50 transmits linearly polarized light having a polarization plane parallel to its transmission axis (vibration plane of the electric field vector) and polarized light perpendicular to the transmission axis. Absorbs linearly polarized light having a surface.

  The linearly polarized light incident on the display unit 100a is transmitted through the protective layer 12 shown in FIG. The linearly polarized light transmitted through the protective layer 12 enters the birefringent layer 13.

  The grooves provided in the region Aa constitute a diffraction grating. Therefore, a part of these linearly polarized light enters the birefringent portion 130a as diffracted light.

  In the birefringent portion 130a, the mesogen is oriented substantially parallel to the X direction. That is, when viewed from the polarizing film 50 side, the slow axis of the birefringent portion 130 a is parallel to the direction rotated 45 ° clockwise relative to the transmission axis of the polarizing film 50. Since the incident light is diffracted light, the incident light includes a light component traveling in the front direction and a light component traveling in the oblique direction. Therefore, for example, the previous linearly polarized light is converted into circularly polarized light, elliptically polarized light, or linearly polarized light according to the birefringence of the birefringent portion 130a and the optical path length. Here, only the left circularly polarized light and the left elliptical polarized light among the light emitted from the birefringent portion 130a will be described.

  These left circularly polarized light and left elliptically polarized light are transmitted through the intermediate layer 16 and reflected by the reflective layer 14. The left circularly polarized light and the left elliptically polarized light are respectively converted into right circularly polarized light and right elliptically polarized light by being reflected by the reflective layer 14. Moreover, since the reflective layer 14 has light scattering properties, this reflected light is scattered light.

The right circularly polarized light and the right elliptically polarized light as the scattered light pass through the intermediate layer 16 and enter the birefringent portion 130a. Since this incident light is scattered light, it includes a light component traveling in the front direction and a light component traveling in an oblique direction. Of the light component traveling in the front direction, the right circularly polarized light having the specific wavelength λ ₀ is converted into linearly polarized light whose polarization plane is perpendicular to the transmission axis of the polarizing film 50 by transmitting through the birefringent portion 130a. The Then, the remaining light component is converted into left elliptically polarized light, left circularly polarized light, right elliptical polarized light, or circularly polarized light by transmitting through the birefringent portion 130a.

  The reflected light from the reflective layer 14 emitted from the birefringent portion 130 a passes through the protective layer 12. In this way, the reflected light from the reflective layer 14 is emitted from the substrate 11 as scattered light.

  As is clear from this, when focusing only on the light component having a polarization plane parallel to the transmission axis of the polarizing film 50, the intensity of the light component emitted by the display unit 100a relative to the intensity of the light component incident on the display unit 100a. This ratio has a wavelength dependency. In other words, the ratio of the intensity of display light emitted from the polarizing film 50 to the intensity of illumination light incident on the polarizing film 50 has wavelength dependency. Therefore, the display unit 101 appears colored. The reason why the display unit 100a appears to be colored will be described later with reference to mathematical expressions.

  The display unit 100b and the display unit 100a differ from each other only in that the length directions of the grooves constituting the diffraction grating are different by 90 ° except for the planar shape. Therefore, the display unit 100b behaves in the same manner as described for the display unit 100a except that the rotation direction of the polarization plane of circularly polarized light or elliptically polarized light is reversed. Therefore, the display unit 100b looks colored in the same manner as the display unit 100a.

  The display unit 100c is different from the display unit 100a only in that no groove is provided at the interface between the birefringent layer 13 and the protective layer 12 and the mesogens are not oriented except for the planar shape. . Therefore, the light emitted from the display unit 100 c is ideally transmitted through the polarizing film 50 without being absorbed by the polarizing film 50. Therefore, the display unit 100c looks silvery white.

  Thus, the display units 100a and 100b appear colored, and the display unit 100c appears silvery white. The display units 100a and 100b have substantially the same brightness. Therefore, when the polarizing film 50 is superimposed on the security device 10 and irradiated with white light and observed from the front, the display units 100a and 100b can be easily distinguished from the display unit 100c as shown in FIG. , Discrimination from each other is impossible or difficult.

Here, the reason why the display unit 100a appears to be colored will be described with reference to mathematical expressions. Incidentally, birefringent portion 130a is directed to act as a quarter wave plate for light of a wavelength lambda _0.

It can be considered that the linearly polarized light having the wavelength λ ₀ emitted from the polarizing film 50 in the normal direction is the sum of the linearly polarized light component whose polarization plane is perpendicular to the X direction and the linearly polarized light component whose polarization plane is perpendicular to the Y direction. it can. As described above, the refractive index in the X-direction of the birefringent portion 130a is extraordinary refractive index n _e, the refractive index in the Y direction is the ordinary index n _o. Accordingly, birefringent portion 130a is in these linearly polarized light component, providing a phase difference of lambda _0/4 in each of the forward path and the backward path. That is, birefringent portion 130a provides a phase difference of lambda _0/2 in total of these linearly polarized light components. Therefore, the light having the wavelength λ ₀ emitted from the display unit 100 a in the normal direction cannot pass through the polarizing film 50.

By the way, the retardation Re depends on the thickness d of the birefringent layer and its birefringence Δn, as shown in the following equation (1).
Re = Δn × d (1)
Here, a Δn = n _e -n _o.

A pair of linearly polarizing films face each other so that their transmission axes are orthogonal to each other, and a birefringent layer is interposed between them so that the optical axis forms an angle θ with respect to the transmission axis of the linearly polarizing film. When one linearly polarizing film is illuminated with light having a wavelength λ from its normal direction, the intensity of light incident on the birefringent layer is I _0, and the intensity of light transmitted through the other linearly polarizing film is I The strength I can be expressed by the following equation (2).
I = I ₀ × sin ² (2θ) × sin ² (Re × π / λ) (2)
The birefringence Δn has wavelength dependence, and the birefringence Δn and the wavelength n are not in a proportional relationship. Therefore, as is clear from equation (2), the spectrum of transmitted light has a different profile from the spectrum of incident light.

  Thus, when the birefringent layer is sandwiched between a pair of linearly polarizing films, transmitted light having a spectrum profile different from that of incident light can be obtained. Similarly, when the birefringent layer is sandwiched between the linearly polarizing film and the reflective layer, reflected light having a spectrum profile different from that of the incident light can be obtained. For this reason, the display unit 100a appears colored.

FIG. 9 is a perspective view illustrating another example of an image displayed by the security device illustrated in FIGS. 1 and 2.
As shown in FIG. 9, when the observation direction is tilted in a plane perpendicular to the X direction from the state shown in FIG. 8, the display colors of the display units 100a and 100b change to different colors. As a result, the display units 100a and 100b can be easily distinguished from each other. For example, if the display units 100a and 100b look orange when observed from the normal direction, the display unit 100a changes to red by tilting the observation direction in a plane perpendicular to the X direction. The part 100b changes to green. The reason for the color change that occurs in the display units 100a and 100b will be described below.

When the observation angle θ is tilted, the effective birefringence Δn ′ of the birefringent layer changes from the birefringence Δn, and the effective film of the birefringent layer shown in the following equation (3): The thickness d ′ is larger than twice the actual film thickness d of the birefringent layer.
d ′ = 2d / cos θ (3)
That is, the retardation Re shown in the above equation (1) changes according to the observation angle, and therefore the intensity I shown in the above equation (2) changes. As a result, the spectrum profile of the display light changes according to the observation angle.

  The birefringence Δn ′ depends on the incident angle of the illumination light and the angle formed by the projection onto the main surface of the birefringent layer that is parallel to the propagation direction of the illumination light with respect to the optical axis of the birefringent layer. To do. Specifically, the birefringence Δn ′ of the birefringent portion 130a does not change even when the observation direction is tilted in a plane perpendicular to the X direction because the optical axis is parallel to the X direction. On the other hand, the birefringence Δn ′ of the birefringent portion 130b changes as the observation direction is tilted in a plane perpendicular to the X direction because its optical axis is parallel to the Y direction.

  As described above, when the display unit 100a is tilted in the plane perpendicular to the X direction, the display unit 100a causes a color change due to an effective change in the film thickness d '. On the other hand, when the viewing direction is tilted in a plane perpendicular to the X direction, the display unit 100b changes color due to an effective change in film thickness d ′ and an effective change in birefringence Δn ′. Produce. Therefore, when the observation direction is tilted in a plane perpendicular to the X direction, the display colors of the display units 100a and 100b change to different colors, and as a result, the display units 100a and 100b can be easily distinguished from each other. Become.

  FIG. 10 is a perspective view showing still another example of an image displayed by the security device shown in FIGS. 1 and 2.

  FIG. 10 depicts an image that can be observed when the security device 10 is rotated 90 ° around the normal line while the security device 10 is overlapped with the polarizing film 50 from the state shown in FIG. 9.

  When the display units 100a and 100b change the rotation angle, the effective grating constant of the diffraction grating changes. When the security device 10 is rotated 90 ° around the normal line together with the polarizing film 50 while the observation direction is oblique, the display color is switched between the display unit 100a and the display unit 100b. Note that the color change described with reference to FIG. 10 also occurs when only the security device 10 is rotated by 90 ° around the normal from the state shown in FIG.

  The security device 10 can be used in a variety of labeled articles.

FIG. 11 is a plan view schematically showing an example of a labeled article.
This labeled article is an ID (identification) card. The labeled article includes a security device 10 and an article 30 that supports the security device 10.

  The article 30 is a card. This article 30 includes a card substrate 31 and printing layers 32a and 32b. The card base 31 is made of plastic, for example. The print layers 32 a and 32 b are formed on the card base 31. The security device 10 is affixed to the card substrate 31.

  The ID card includes the security device 10 described above. Therefore, forgery of this ID card is difficult. In addition, since the ID card includes the security device 10, it is easy to determine an article whose authenticity is unknown between genuine and non-authentic. Moreover, since this ID card further includes the print layers 32a and 32b in addition to the security device 10, it is possible to adopt a counterfeit prevention measure using them.

  In addition, in FIG. 11, although the ID card is illustrated as an article with a label, an article with a label is not restricted to this. For example, the labeled article may be other cards such as an IC (integrated circuit) card, a magnetic card, and a wireless card. Alternatively, the labeled article may be securities such as gift certificates and stock certificates. Alternatively, the labeled article may be a bill, a deposit, or a savings passbook. Thus, the security device 10 can be applied to various printed materials.

  Moreover, the labeled article may not be a printed material. That is, the security device 10 may be supported on an article that does not include a printed layer. For example, the security device 10 may be supported by a luxury product such as a work of art.

Various modifications can be made to the security device 10 shown in FIGS. 1 and 2.
FIG. 12 is a cross-sectional view schematically showing a modification of the security device shown in FIGS. 1 and 2. The security device 10 shown in FIG. 12 is the same as the security device 10 described with reference to FIGS. 1 and 2 except that the following configuration is adopted.

  That is, in this security device 10, instead of providing a groove at the interface between the protective layer 12 and the birefringent layer 13, a groove is provided at the interface between the intermediate layer 16 and the birefringent layer 13, and the protective layer 12 is omitted. ing. In this security device 10, the length direction of the groove is made equal between the region Aa and the region Ab, and the thickness of the birefringent layer 13 is made different between the birefringent portion 130a and the birefringent portion 130b. In other words, the birefringent portion 130a and the birefringent portion 130b have the same mesogen orientation direction, and the birefringent portion 130a and the birefringent portion 130b have different retardation.

  When such a structure is adopted, the display units 100a and 100b look the same color when observed with the naked eye even if the scattering ability of the reflective layer 14 is small. And when observing through the polarizing film 50, the display parts 100a and 100b can be easily distinguished from each other.

  Further, in the labeled article obtained by attaching the security device 10 to the article 30, when the security device 10 is to be peeled off from the article 30, the birefringence is the same as described with reference to FIGS. The layer 13 or the laminate including the layer 13 is broken or deformed.

  FIG. 13 is a cross-sectional view schematically showing another modification of the security device shown in FIGS. 1 and 2.

  The security device 10 shown in FIG. 13 is the same as the security device 10 described with reference to FIGS. 1 and 2 except that the following configuration is adopted.

  That is, in this security device 10, instead of providing a groove at the interface between the protective layer 12 and the birefringent layer 13, a groove is provided at the interface between the intermediate layer 16 and the birefringent layer 13, and the protective layer 12 is omitted. ing. In this security device 10, the reflective layer 14 is omitted, and a colored layer 17 and a transparent layer 18 are further included. According to this security device 10, for example, transmissive display is possible.

  The colored layer 17 and the transparent layer 18 are interposed between the base material 11 and the intermediate layer 16. The colored layer 17 and the transparent layer 18 are adjacent to each other in a direction parallel to one main surface of the substrate 11. When the colored layer 17 is provided, the design of the security device 10 can be improved.

  The colored layer 17 is a black pattern, a colored pattern other than black, or a combination of a plurality of colored patterns having different display colors. The colored layer 17 can be formed by, for example, a printing method.

  The transparent layer 18 is colorless and transparent or colored and transparent. The transparent layer 18 is provided to enable transmissive display. The transparent layer 18 can further serve as a planarizing layer when the colored layer 17 is patterned, for example. The transparent layer 18 may be omitted.

  Examples of the material of the transparent layer 18 include acrylic resin, urethane resin, epoxy resin, vinyl chloride resin, styrene resin, cellulose resin, acetal resin, polyamide resin, polyimide resin, olefin resin, polycarbonate resin, polyether resin, polyester resin. Phenolic resins or melamine resins can be used. As a material for the transparent layer 18, an inorganic material such as glass and quartz may be used. Alternatively, the transparent layer 18 may be an air layer. That is, the transparent layer 18 may be a space in an opening provided in the colored layer 17.

  The colored layer 17 and the transparent layer 18 may not be disposed between the base material 11 and the intermediate layer 16. For example, the colored layer 17 and the transparent layer 18 may be disposed on the front surface of the birefringent layer 13. Alternatively, the colored layer 17 and the transparent layer 18 may be disposed between the base material 11 and the adhesive layer 15.

  In the labeled article formed by attaching the security device 10 to the article 30, when the security device 10 is to be peeled from the article 30, the birefringent layer 13 is the same as described with reference to FIGS. 3 to 6. Or the destruction or deformation | transformation of the laminated body containing this will be produced.

  In addition, when performing a transmissive display, the article to which the security device 10 is attached needs to include a light transmission part. The light transmissive portion may be optically anisotropic, but is typically optically isotropic. Even if the reflective layer 14 is not omitted or the transmissive display is not performed, the security device 10 may include the colored layer 17 or a combination of the colored layer 17 and the transparent layer 18.

  Instead of using a nematic liquid crystal material as the liquid crystal material, a cholesteric liquid crystal material may be used. When a cholesteric liquid crystal material is used, display utilizing selective reflectivity and circular polarization selectivity is possible.

Selective reflectivity is a property in which a cholesteric liquid crystal material strongly reflects light in a specific wavelength band of incident light. The central wavelength λ _{s of the} wavelength band in which the cholesteric liquid crystal material causes selective reflection and the wavelength band width Δλ in which the cholesteric liquid crystal material causes selective reflection are represented by the following equations (4), where the average refractive index of the cholesteric liquid crystal material is nm. ) And (5).

λ _s = nm × P (4)
Δλ = Δn × P / nm (5)
Here, the average refractive index nm is ^{_{1/2 [(n o 2 + n}} e 2) / 2], Δn is n _e -n _o.

As is clear from equations (4) and (5), the center wavelength λ _s and the wavelength bandwidth Δλ depend on the helical pitch P. Therefore, reflected light with high color purity can be obtained by appropriately setting the helical pitch P.

Equations (4) and (5) are applicable when light is irradiated from a direction parallel to the helical axis of the helical structure formed by the mesogen. When the incident direction of light is inclined with respect to the spiral axis, the apparent spiral pitch P increases. As a result, the center wavelength λ _s shifts to the short wavelength side, and the wavelength band width Δλ becomes narrow. Accordingly, when the angle formed by the observation direction and the spiral axis is increased, the display color is shifted to the short wavelength side.

  The circularly polarized light selectivity is a property that the cholesteric liquid crystal material reflects only one of the right circularly polarized light and the left circularly polarized light and transmits the other. For example, when the spiral structure formed by the mesogen of the cholesteric liquid crystal material is clockwise, the cholesteric liquid crystal material reflects only the right circularly polarized light and transmits the left circularly polarized light. The reflected light at this time is right circularly polarized light.

  As described above, when a cholesteric liquid crystal material is used instead of a nematic liquid crystal material as a liquid crystal material, selective reflection and circular polarization selectivity can be used for display. For example, in the security device 10 described with reference to FIG. 13, if a cholesteric liquid crystal material is used as the liquid crystal material, it is possible to perform authenticity determination using a difference between the color of transmitted light and the color of reflected light. That is, in this case, it is not necessary to use a polarizer for authenticity determination. When a cholesteric liquid crystal material is used as the liquid crystal material, authenticity determination may be performed using a polarizer.

  When a cholesteric liquid crystal material is used, the helical pitch P is, for example, in the visible light range. Generally, when the helical pitch P is in the range of 380 nm to 780 nm, it is possible to make a true / false determination by visual observation. In general, when the helical pitch P is in the range of 400 nm to 700 nm, it is easy to determine the authenticity by visual observation.

  When a cholesteric liquid crystal material is used, the birefringent layer 13 may have a single layer structure or a multilayer structure.

  In the former case, the security device 10 can display different colors when it is irradiated with natural light, when it is irradiated with right circularly polarized light, and when it is irradiated with left circularly polarized light.

  In the latter case, by stacking two layers having the same spiral pitch P and different rotational directions of the spiral, different colors are obtained when irradiated with natural light and when irradiated with one of right circularly polarized light and left circularly polarized light. Can be displayed, and the same color can be displayed when irradiated with natural light and when irradiated with the other of right circularly polarized light and left circularly polarized light. When this structure is adopted, the color of transmitted light and the color of reflected light are different.

  In the latter case, by laminating a plurality of layers having different spiral pitches P, it is possible to express a color tone that cannot be expressed by a single layer structure, for example, when observed with the naked eye. When observed using a circular polarizer, different colors are displayed depending on the characteristics of the circular polarizer, for example, the design wavelength of the circularly polarized light transmitted by the circular polarizer and the rotation direction of the electric field vector. Is possible.

  When the cholesteric liquid crystal material is used, the birefringent layer 13 may include a plurality of birefringent portions that are adjacent to each other in the in-plane direction and have different helical pitches and / or rotational directions of the helix. By adopting this structure, it is possible to achieve excellent design properties and a better anti-counterfeit effect. For example, when the spiral pitch P in the former and the spiral pitch P in the latter are equal to each other, it is impossible or difficult to distinguish the display portions corresponding to these birefringent portions from each other with the naked eye. In this case, the display units corresponding to these birefringent portions can be easily discriminated from each other by observing them using a circular polarizer.

  When a cholesteric liquid crystal material is used, the birefringent layer 13 may include a birefringent portion that selectively reflects right circularly polarized light and a birefringent portion that selectively reflects left circularly polarized light. When the spiral pitch P in the former and the spiral pitch P in the latter are equal to each other, it is impossible or difficult to distinguish the display portions corresponding to these birefringent portions from each other with the naked eye. In this case, the display units corresponding to these birefringent portions can be easily discriminated from each other by observing them using a circular polarizer.

  When using a cholesteric liquid crystal material, the security device 10 may include a colored layer 17 having a relatively low reflectance such as a black layer. By providing such a colored layer 17, a clearer image can be obtained.

  When a cholesteric liquid crystal material is used, the birefringent layer 13 can be formed by the following method, for example.

  That is, mesogens of low molecular weight liquid crystal molecules are cholesterically aligned and, for example, light or heat is applied to cause cross-linking of the liquid crystal molecules while maintaining the previous alignment state. Alternatively, the side chain or main chain type thermotropic polymer liquid crystal material is heated to the glass transition temperature or higher, and the mesogens are cholesterically aligned in this state, and then the liquid crystal material is maintained in the glass while maintaining the previous alignment state. Cool below the transition temperature. Alternatively, the mesogen of the side chain type or main chain type lyotropic polymer liquid crystal material is cholesterically aligned, and the solvent is gradually removed while maintaining this alignment state. From the viewpoint of production, among these methods, a method using a low molecular weight liquid crystal molecule is preferable.

As the side chain type polymer liquid crystal material, for example, polyacrylate, polymethacrylate, polysiloxane or polymalonate containing mesogen in the side chain can be used. As the main chain type polymer liquid crystal material, for example, polyester, polyester amide, polycarbonate, polyamide or polyimide containing mesogen in the main chain can be used.
The invention described in the original claims is appended below.
[1]
The substrate is made of a solidified liquid crystal material supported on one main surface of the substrate, and at least one of a plurality of one-dimensional or two-dimensionally arranged openings and one or more cuts is provided. A security device comprising a birefringent layer.
[2]
The security device according to [1], wherein the birefringent layer is provided with the plurality of openings arranged two-dimensionally.
[3]
The security device according to [1] or [2], wherein the one or more cuts are provided in the birefringent layer.
[4]
[1] to [1], further comprising a reflective layer that is interposed between the base material and the birefringent layer or faces the birefringent layer with the base material interposed therebetween. [3] The security device according to any one of [3].
[5]
[4] The security device according to [4], wherein the birefringent layer is made of a cholesteric liquid crystal material, and the reflective layer is a colored layer.
[6]
The security device according to any one of [1] to [5], further comprising a light-transmitting intermediate layer interposed between the base material and the birefringent layer.
[7]
Any one of [1] to [6], wherein the base material is provided with at least one of a plurality of openings arranged one-dimensionally or two-dimensionally and one or more cut lines. The security device described in the section.
[8]
[1] An article with a label comprising the security device according to any one of [7] and an article that supports the security device.

The top view which shows roughly the security device which concerns on the 1st aspect of this invention. Sectional drawing along the II-II line of the security device shown in FIG. The top view which shows roughly an example of the structure obtained when the security device shown in FIG.1 and FIG.2 is affixed on articles | goods, and this is peeled. The top view which shows roughly the other example of the structure obtained when the security device shown in FIG.1 and FIG.2 is affixed on articles | goods, and this is peeled. The top view which shows roughly the birefringent layer before peeling. The top view which shows roughly the birefringent layer after peeling. The top view which shows an example of the image which the security device shown in FIG.1 and FIG.2 displays. The top view which shows roughly an example of the image which can be observed when the security device shown in FIG.1 and FIG.2 and a linearly polarizing film are piled up. The perspective view which shows the other example of the image which the security device shown in FIG.1 and FIG.2 displays. The perspective view which shows the further another example of the image which the security device shown in FIG.1 and FIG.2 displays. The top view which shows an example of a labeled article schematically. Sectional drawing which shows roughly the modification of the security device shown in FIG.1 and FIG.2. Sectional drawing which shows schematically the other modification of the security device shown in FIG.1 and FIG.2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Security device, 11 ... Base material, 12 ... Protective layer, 13 ... Birefringent layer, 14 ... Reflective layer, 15 ... Adhesive layer, 16 ... Intermediate layer, 17 ... Colored layer, 18 ... Transparent layer, 30 ... Article 31 ... Card base material, 32a ... Print layer, 32b ... Print layer, 50 ... Polarizing film, 100a ... Display part, 100b ... Display part, 100c ... Display part, 130a ... part, 130b ... part, 130c ... part, Aa ... area, Ab ... area, Ac ... area, NT ... cut, OP ... opening.

Claims (7)

The substrate is made of a solidified liquid crystal material supported on one main surface of the substrate, and at least one of a plurality of one-dimensional or two-dimensionally arranged openings and one or more cuts is provided. A birefringent layer;
A reflective layer interposed between the base material and the birefringent layer or facing the birefringent layer with the base material sandwiched therebetween
And the reflective layer is made of a mixture containing a light transmissive resin and metal particles .   The security device according to claim 1, wherein the birefringent layer is provided with the plurality of openings arranged two-dimensionally.   The security device according to claim 1, wherein the one or more cuts are provided in the birefringent layer. The security device according to any one of claims 1 to 3, wherein the birefringent layer is made of a cholesteric liquid crystal material, and the reflective layer is a colored layer. The security device according to any one of claims 1 to 4 , further comprising a light-transmitting intermediate layer interposed between the base material and the birefringent layer. 6. The substrate according to any one of claims 1 to 5 , wherein at least one of a plurality of openings and one or more cuts arranged one-dimensionally or two-dimensionally is provided on the base material. The listed security device. An article with a label, comprising: the security device according to any one of claims 1 to 6 ; and an article that supports the security device.

Images