JP2012245697A - Display body, and article with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve higher forgery prevention effect.SOLUTION: A display body includes a first optical effect layer and a second optical effect layer, the first optical layer including a first interface section and a second interface section, the first interface section being provided with plural projections and/or recesses two-dimensionally arranged with minimum center distance within the range of 200 nm to 500 nm each having forward tapered shape, and with at least a part thereof being covered with a reflective material layer, the second interface section being formed of a light scattering region of plural linear projections and/or recesses with same orientation or of plural projections and/or recesses with same orientation, with plural planar shapes being circular, elliptical or polygonal shape, and with at least a part thereof being covered with a reflective material layer, the second optical effect layer including a section opposing the reflective material layer with the first optical effect layer in between or opposing the first optical effect layer with the reflective material layer in between, and including at least one of cholesteric liquid crystal, pearl pigment, and multi-layered interference membrane.

Description

  The present invention relates to an optical technique that provides an anti-counterfeit effect, a decorative effect and / or an aesthetic effect.

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

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

  A first interface portion provided with a relief type diffraction grating composed of a plurality of grooves, and a two-dimensional arrangement with a center distance smaller than the minimum center distance of the plurality of grooves, and each of which is a forward taper. There has been proposed a display body comprising a second interface portion provided with a plurality of concave portions or convex portions having a shape. This display body includes a high-definition structure and has special optical characteristics (Patent Document 1).

  Further, there is a flat mirror surface portion and a relief structure, and this relief structure has been proposed having a period shorter than a predetermined limit wavelength λ at the short wavelength end of the visible light spectrum (Patent Document 2).

JP 2008-107470 A Japanese Patent No. 4315334

  An object of the present invention is to realize a higher anti-counterfeit effect, and by adding a new optical effect to the above-described conventional technology, a high security effect that can make unauthorized fraud counterfeit difficult It is providing the optical element which has these.

As a means for solving the above problems, the invention according to claim 1 is a two-dimensional arrangement with a minimum center-to-center distance within a range of 200 nm to 500 nm, and a plurality of protrusions each having a forward taper shape. A first interface portion provided with a portion and / or a recess and at least partially covered by a reflective material layer
Reflected by light scattering regions of a plurality of linear convex portions and / or concave portions having a uniform direction, or a plurality of convex portions and / or concave portions having a plurality of planar shapes having an elliptical shape or a polygonal shape. A first optical effect layer comprising: a second interface portion at least partially covered with a functional material layer;
A cholesteric liquid crystal, a pearl pigment, comprising a portion facing the reflective material layer with the first optical effect layer interposed therebetween or a portion facing the first optical effect layer with the reflective material layer interposed therebetween And a second optical effect layer including at least one of the multilayer interference films.

  The invention according to claim 2 is an article with a display body, comprising a base material and the display body according to claim 1 supported by the base material.

  The invention according to claim 3 is the article with a display body according to claim 2, wherein the base material is paper, and the display body is embedded in the paper.

  The invention according to claim 4 is the article with a display body according to claim 3, wherein the display body has a thread shape.

  Unlike conventional optical elements, it is possible to provide an optical element that has a novel appearance such as color change, color change due to complementary color, diffracted light, and scattered light, and has an anti-counterfeit effect, a decorative effect, and an aesthetic effect.

The top view which shows schematically the display body which concerns on 1 aspect of this invention. Sectional drawing along the X-X 'line | wire of the display body shown in FIG. The top view which shows roughly an example of the linear anisotropic scattering area | region employable as the 2nd interface part of the display body shown in FIG.1 and FIG.2. The perspective view which shows roughly the example of the anisotropic scattering area | region containing the convex part and / or recessed part of shapes other than the line | wire shape which can be employ | adopted as the 2nd interface part of the display body shown in FIG.1 and FIG.2. The perspective view which shows roughly the example of the anisotropic scattering area | region containing the convex part and / or recessed part of shapes other than the line | wire shape which can be employ | adopted as the 2nd interface part of the display body shown in FIG.1 and FIG.2. The perspective view which shows an example of the structure employable as the 1st interface part of the display body shown in FIG.1 and FIG.2.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view of the present invention, and FIG. 2 is a cross-sectional view of the X-X ′ plane of FIG. 1, which is an optical element to which a color shift effect is added in addition to a high-definition structure. Specifically, it has a first optical layer 3 and a second optical layer 4, the first optical layer 3 has an optical structure forming layer 5 and a reflective layer 6, and the optical structure forming layer 5 is at least a first optical layer. It has one interface part 1 and a second interface part 2.

  As shown in FIG. 6 as an example of the structure, the first interface 1 is two-dimensionally arranged with a minimum center-to-center distance within a range of 200 to 500 nm, and each of the first interface 1 has a forward tapered shape. The second interface portion 2 has an anisotropic scattering structure consisting of concave portions or convex portions, and the second optical layer 4 has a multilayer interference structure.

  The second interface portion 2 has an anisotropic scattering structure 8 composed of a plurality of linear concave portions or convex portions that are aligned, and the second optical layer 4 is a cholesteric liquid crystal layer or a film having a different refractive index. Is a multilayer interference film in which a plurality of layers are laminated. When observing specularly reflected light, the color change (color A⇒color B) by the second optical layer 4 is caused at the first interface portion 1 due to a change in reflection angle (approximately 0 ° to 45 ° with respect to the vertical direction). In the second interface 2, it is possible to recognize a color change (complementary color of color A → complementary color of color B) due to the complementary color of the color visible on the second optical layer 4.

  FIG. 3 is a schematic plan view showing an example of a linear anisotropic scattering region that can be employed in the second interface portion of the display body shown in FIGS. 1 and 2, and a plurality of linear convex portions having uniform directions and It consists of concave portions, and the reflected light differs in the direction perpendicular to the straight direction and the straight line. 4 and 5 show examples of anisotropic scattering regions including convex portions and / or concave portions having a planar shape other than lines, and show similar effects. When the concavo-convex structure of the anisotropic scattering region is a polygon as shown in FIG. 4, the fact that the direction of the planar shape of the concavo-convex structure is aligned means that the directions of the sides of the polygon are aligned. In particular, the rectangular shape is preferable because anisotropy increases in a direction parallel to two orthogonal sides. Further, in the case of an ellipse as shown in FIG. 5, the fact that the plane direction is aligned means that the major axis directions of the ellipse are aligned.

  When the viewing angle is observed at a deep angle (approximately 70 ° to 90 ° with respect to the vertical direction), diffracted light from the first optical layer can be recognized at the first interface portion, and scattered light is scattered at the second interface portion. Can be recognized. Thus, it can be a novel optical element that looks different from the conventional optical element.

  Further, by making the second interface portion 2 an anisotropic scattering structure 8 composed of a plurality of linear concave portions or convex portions having the same direction, a change in reflection angle (in the vertical direction) is observed when specular reflection light is observed. On the other hand, in the scattering direction of the second interface portion 2, the color change (color A → color B) is a complementary color change (color A⇒color B) seen by the second optical layer 4 at the first interface. Complementary color ⇒ complementary color of color B) can be recognized, and light absorption can be recognized in the non-scattering direction. Further, when the viewing angle is observed at a deep angle (approximately 70 ° to 90 ° with respect to the vertical direction), scattered light can be recognized in the scattering direction of the second interface 2 and light absorption can be recognized in the non-scattering direction.

  The first optical layer 3 can be formed on a substrate. As the substrate, a known plastic film such as PET can be used.

  The first optical layer 3 has an optical structure forming layer 5, for example, a light transmissive thermoplastic resin, a thermosetting resin, and an ultraviolet ray or an electron beam curable resin (hereinafter also referred to as a photocurable resin). The resin is used. When a thermoplastic resin, a thermosetting resin, or a photocurable resin is used as the material of the first optical layer 3, a concave structure and / or a convex structure is easily formed on one main surface by transfer using the original plate. be able to.

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

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

The reflective layer 6 covers at least a part of the first interface portion 1. As the reflective layer 6, for example, a metal or alloy layer made of a metal material such as aluminum, silver, tin, chromium, nickel, copper, gold, and alloys thereof can be used. In this case, the reflective layer 6 is typically formed using a vacuum film forming method. Examples of the vacuum film forming method include a vacuum deposition method and a sputtering method. The thickness of the reflective layer 6 is, for example, in the range of 1 nm to 100 nm.

  The reflective layer 6 plays a role of displaying an image with better visibility on the display body. Further, by providing the reflective layer 6, it is possible to make it difficult to cause damage to the concave structure and / or the convex structure provided on one main surface of the first optical layer 3.

  The first interface 1 has a high-definition structure so that light is absorbed at a shallow angle and diffracted light can be recognized at a deep angle. The first interface portion 1 is provided with a plurality of concave portions or convex portions as shown in FIG. These concave portions or convex portions are two-dimensionally arranged with a minimum center-to-center distance within a range of 200 nm to 500 nm. The recesses or protrusions are typically arranged regularly. Each of the concave portion or the convex portion has a forward tapered shape. The depth or height of the recess or protrusion is usually greater than the depth of the groove, typically in the range of 0.3 μm to 0.5 μm. The ratio of the depth or height (hereinafter also referred to as the aspect ratio) to the minimum center distance between the concave portions or the convex portions is, for example, in the range of 0.5 to 1.5.

  These structures can be formed during or after the formation of the optical structure forming layer 5 using a plate. The second interface 2 has a scattering structure. Further, the anisotropic scattering structure 8 shown in FIGS. 3, 4, and 5 that scatters depending on the direction may be used.

  The second optical layer includes a portion facing the first optical layer 3. In FIG. 2, as an example, a case where the second optical layer faces the optical structure forming layer 5 side and faces the entire first optical layer 3 with the reflective layer 6 facing outward is illustrated. The layer may face the entire first optical layer 3 with the reflective layer 6 interposed between the optical structure forming layer 5 and the optical structure forming layer 5. The lamination of the second optical layer and the first optical layer may be formed directly on the first optical layer, or may be formed on another substrate and transferred to the first optical layer via an adhesive and laminated. May be.

  The second optical layer includes at least one of a cholesteric liquid crystal, a pearl pigment, and a multilayer interference film. The second optical layer typically includes cholesteric liquid crystal. When the second optical layer includes a cholesteric liquid crystal, the second optical layer is, for example, a material including a compound having a cholesteric structure, or a nematic liquid crystal having a cholesteric structure by adding a chiral agent. It can be manufactured using the contained material. The cholesteric liquid crystal can change the helical pitch and the twist direction of the polarization plane, for example, by changing the amount and type of the chiral agent added to the nematic liquid crystal.

  In addition, a polymerizable group such as an acrylic group can be introduced at both ends of the liquid crystal molecule. This makes it easy to fix the alignment after aligning the liquid crystal molecules. When the second optical layer contains cholesteric liquid crystal, the second optical layer 4 may be a layer made of cholesteric liquid crystal or a layer containing a cholesteric liquid crystal pigment.

  When the second optical layer 4 contains a pearl pigment, the second optical layer 4 is typically formed by a printing method or a coating method. As these printing methods or coating methods, known methods can be employed. The multilayer interference film that can be included in the second optical layer 4 is formed by laminating a plurality of layers having different refractive indexes. Each layer constituting the multilayer interference film is, for example, a metal thin film, a ceramic thin film, or an organic polymer thin film. The multilayer interference film includes, for example, an alternating laminate of layers having different refractive indexes. For example, a ceramic thin film or a metal thin film having a light transmittance in the range of 20 to 70% and an organic polymer thin film are alternately laminated with a predetermined thickness to absorb or reflect only visible light having a specific wavelength. A multilayer interference film is obtained.

Examples of materials that can be used for each layer constituting the multilayer interference film are given below. In the following, the numerical values in parentheses described after the chemical formula or the compound name represent the respective refractive indexes. As ceramics, Sb ₂ O ₃ (3.0), Fe ₂ O ₃ (2.7), TiO ₂ (2.6), CdS (2.6), CeO ₂ (2.3), ZnS (2 .3), PbCl ₂ (2.3), CdO (2.2), Sb ₂ O ₃ (2.0), WO ₃ (2.0), SiO (2.0), Si ₂ O ₃ (2 .5), In ₂ O ₃ (2.0), PbO (2.6), Ta ₂ O ₃ (2.4), ZnO (2.1), ZrO ₂ (2.0), MgO (1. 6), Si ₂ O ₂ (1.5), MgF ₂ (1.4), CeF ₃ (1.6), CaF ₂ (1.3 to 1.4), AlF ₃ (1.6), Al Mention may be made of ₂ O ₃ (1.6) and GaO (1.7).

  Examples of the metal include Al, Fe, Mg, Zn, Au, Ag, Cr, Ni, Cu, Si, and alloys thereof. Examples of the organic polymer include polyethylene (1.51), polypropylene (1. 49), polytetrafluoroethylene (1.35), polymethyl methacrylate (1.49) and polystyrene (1.60).

  When the second optical layer 4 includes a multilayer interference film, the second optical layer 4 is formed using a known method capable of controlling the film thickness, the deposition rate, the number of layers, the optical film thickness, and the like. Examples of such a method include a vacuum deposition method, a sputtering method, and a chemical vapor deposition method (CVD method). The optical film thickness is a product of the refractive index and the film thickness.

  Alternatively, the multilayer interference film may be a multilayer film formed by multilayer simultaneous extrusion. This multilayer film is an alternating laminate of a plurality of plastic thin films having different refractive indexes. Each of these plastic thin films contains a plastic material. Each of these plastic thin films may contain an auxiliary agent as required.

  When observing specularly reflected light, it recognizes the color change (color A ⇒ color B) caused by the second optical layer 4 at the first interface due to changes in the reflection angle (approximately 0 ° to 45 ° with respect to the vertical direction). In the second interface part, it is possible to recognize a color change (complementary color of color A → complementary color of color B) due to the complementary color of the color seen by the second optical layer 4 in the first interface part.

  The color change of the second interface 2 is an original color change of the multilayer film. When the colors A and B are related to the color of the multilayer film, the color A: the complementary color of the original color A ′ of the multilayer film, the color B: the multilayer film It is a complementary color of the original color B ′.

  When the first interface portion 1 and the second optical layer (when a multilayer film is used) are combined, the multilayer film only: complementary color A when tilted by approximately 0 ° to 45 ° to 70 ° to 90 ° with respect to the vertical direction -Color B complementary color-Transparent-Transparent, first interface 1 only: Black-Black-Color change (diffracted light) due to structure of first interface 1-Color (diffracted light) due to structure of first interface 1 If there is a multilayer film on the black surface of the first interface 1, a complementary color of the original color of the multilayer film can be seen. When combined, it looks like color A to color B to color change (diffracted light) due to the structure of the first interface 1 to color due to the structure of the first interface 1 (diffracted light).

  When the viewing angle is observed at a deep angle (approximately 70 ° to 90 ° with respect to the vertical direction), diffracted light from the first optical layer 3 can be recognized at the first interface portion 1, and at the second interface portion 2, , Can recognize scattered light. Thus, it can be a novel optical element that looks different from the conventional optical element.

  The optical element of the present invention may be provided with an adhesive layer 7 as a seal, or may be formed on a peelable substrate and used as a transfer foil. It may also be squeezed into paper.

DESCRIPTION OF SYMBOLS 1 ... 1st interface part 2 ... 2nd interface part 3 ... 1st optical layer 4 ... 2nd optical layer 5 ... Optical structure formation layer 6 ... Reflective layer 7 ... Adhesive layer 8: anisotropic scattering structure

Claims (4)

A plurality of convex portions and / or concave portions, which are two-dimensionally arranged with a minimum center-to-center distance within a range of 200 nm to 500 nm and each have a forward tapered shape, are provided and are at least partially covered by a reflective material layer. A first interface portion;
A plurality of linear convex portions and / or concave portions having a uniform direction, or a plurality of planar shapes having a uniform direction are composed of light scattering regions of a plurality of convex portions and / or concave portions that are elliptical or polygonal, A first optical effect layer comprising: a second interface portion at least partially covered with a reflective material layer;
A cholesteric liquid crystal, a pearl pigment, comprising a portion facing the reflective material layer with the first optical effect layer interposed therebetween or a portion facing the first optical effect layer with the reflective material layer interposed therebetween And a second optical effect layer including at least one of the multilayer interference films.   An article with a display body comprising a base material and the display body according to claim 1 supported by the base material.   The article with a display body according to claim 2, wherein the substrate is paper, and the display body is embedded in the paper.   The article with a display body according to claim 3, wherein the display body has a thread shape.

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