Optical structure, method for manufacturing the same, and code formation method

Abstract

Provided is an optical structure capable of forming a code that is difficult to forge, and achieves both high readability and aesthetics. An optical structure of the present invention comprises: a reflective layer with specular reflectivity; and a printed layer as a diffuse reflector with diffuse reflectivity, which is stacked on at least a part of the reflective layer. In the printed layer, an image portion which is recognizable when viewed from the stacking direction is formed. The image portion has printed light-color level areas, and a non-light-color level area interposed between the light-color level areas.

Description

Technical Field

[0001] Embodiments of the present invention relate to an optical structure, a method for manufacturing the same, and a method for forming a code such as a barcode.

Background Art

[0002] Currently, barcodes and two-dimensional codes are printed on objects and widely used. Recently, identification using two-dimensional codes on smartphones is also becoming popular.

[0003] Barcodes are used by displaying patterns not only on paper but also on various screens such as liquid crystal screens and glass, and the codes are read by machines. Also, if the object can be decorated, etc., the convenience and appearance of the object will be improved.

[0004] Therefore, Japanese Patent Application Laid-Open No. 2002-192867 proposes a method of including a light diffraction effect in a code.

Summary of the Invention

[0005] However, in the conventional technology, since the layer structure of the optical element is limited and the code is formed of metal, there are problems such as poor appearance and that the code cannot be read from a shiny surface because black is used for the code.

[0006] In addition, barcodes and two-dimensional codes by black-and-white printing can be easily printed by anyone with a printer, so they are highly convenient, but counterfeit products can be easily manufactured. Also, since the counterfeited code is printed in black on white paper just like the genuine product, it may be difficult to determine whether it is counterfeited.

[0007] In view of the above circumstances, a first object of the present invention is to provide an optical structure and a method for manufacturing the same that can form a code that is difficult to counterfeit and achieves both high readability and aesthetics.

[0008] Another object of the present invention is to provide an optical structure provided with a code that can be read even from a shiny surface and a method for forming the code.

[0009] In order to achieve the first object, the optical structure according to the first aspect of the present invention has a reflective layer having specular reflectivity and a printing layer as a diffusive reflector having diffusive reflectivity laminated on at least a part of the reflective layer. An image portion recognizable when viewed from the lamination direction is formed in the printing layer, and the image portion has a printed light color level region and a non-light color level region sandwiched between the light color level regions.

[0010] In order to achieve the first object, the optical structure according to the second aspect includes a spacer layer having translucency or transparency between the printing layer and the reflective layer in the optical structure according to the first aspect.

[0011] In order to achieve the first object, the optical structure according to the third aspect includes a protective layer having translucency or transparency that covers the printing layer in the optical structure according to the first or second aspect.

[0012] In order to achieve the first object, the optical structure according to the fourth aspect further includes an embossed layer having an uneven structure between the spacer layer and the reflective layer or between the spacer layer and the printing layer in the optical structure according to the second aspect.

[0013] In order to achieve the first object, the optical structure according to the fifth aspect includes a first optical structure that is an optical structure according to the second or fourth aspect and a second optical structure that is an optical structure according to the second or fourth aspect, and the reflective layer of the first optical structure and the reflective layer of the second optical structure are joined together.

[0014] In order to achieve the first object, in the optical structure according to any one of the first to fifth aspects, the non-light color level region is a black level region.

[0015] The optical structure according to the seventh aspect has, in order to achieve the second object, a reflective layer having specular reflectivity, and a plurality of printed light-level regions disposed on at least a part of the reflective layer, and arranges a machine-readable code formed by a combination of the plurality of light-level regions.

[0016] The optical structure according to the eighth aspect is the optical structure according to any one of the first to seventh aspects, in order to achieve the first or second object, and the reflective layer is a mirror layer.

[0017] The optical structure according to the ninth aspect is the optical structure according to the eighth aspect, in order to achieve the first or second object, and the reflective layer is a vapor deposition layer.

[0018] The optical structure according to the tenth aspect is the optical structure according to any one of the first to ninth aspects, in order to achieve the first or second object, and the light-level region is a white-level region.

[0019] The manufacturing method according to the eleventh aspect, in order to achieve the first object, prepares a reflective layer that specularly reflects incident light, laminates a spacer layer having translucency or transparency on the reflective layer, and laminates a printing layer having an image portion having a machine-readable code formed by a light-level region that is a printed portion and a non-light-level region sandwiched between the light-level regions on at least a part of the spacer layer, and manufactures an optical structure by covering the spacer layer and the printing layer with a protective layer.

[0020] The manufacturing method according to the twelfth aspect is a method of forming a machine-readable code by using the base color of a product and the color of the base of a label covering the product, in order to achieve the second object, forming a plurality of light-level regions with one of the base color or the base color, forming a plurality of non-light-level regions with the other of the base color or the base color, and forming a machine-readable code by a combination of the plurality of light-level regions.

[0021] According to the present invention, it is possible to provide an optical structure capable of forming a code that is difficult to forge and that achieves both high readability and aesthetic appearance, and a method for manufacturing the same. Further, according to the present invention, it is possible to provide an optical structure provided with a code that can be read even from a glossy surface, and a method for forming the code.

Brief Description of the Drawings

[0022]

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DETAILED DESCRIPTION OF THE INVENTION

[0023] Embodiments of the present invention are a group of embodiments based on a single unique invention from the background. Also, each aspect of the present invention is an aspect of a group of embodiments based on a single invention. Each configuration of the present invention may have each aspect of the present disclosure. Each feature of the present invention is combinable and can form each configuration. Therefore, each feature of the present invention, each configuration of the present invention, each aspect of the present disclosure, and each embodiment of the present invention can be combined, and the combination has a synergistic function and can exhibit a synergistic effect.

[0024] [First Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to FIG. 1.

[0025] FIG. 1 is a diagram for conceptually explaining the structure of the optical structure 1 according to the first embodiment of the present invention.

[0026] That is, the optical structure 1 is formed by laminating a printing layer 30 as a scattering reflector having scattering reflectivity on a part of a reflection layer 10 having regular reflectivity. The printing layer 30 includes a printed area and a non-printed area. The printed area includes underprinting. In particular, the printed area of the code is preferably underprinted and the white level of the code is formed.

[0027] The underprinting is preferably printed with white or light-colored opaque ink. The underprinting can be used as a base for printing the white level of the code and a single or a combination of a picture, pattern, logo, crest, natural motif, geometric pattern, emblem, crest, or text of the product.

[0028] For the underprinting of the prints of the patterns, designs, logos, emblems, natural motifs, geometric patterns, emblems, coats of arms, or texts of these products, either alone or in combination, and the printing of the white level of the code, the same ink can be used. Preferably, the white level is such that L* in the LAB color system in the two-degree field of view when measured by the SCE method is 50 or more.

[0029] (Direction definition) In the present embodiment, the direction in which the printing layer 30 and the reflective layer 10 are laminated (that is, the vertical direction in FIG. 1) is referred to as the lamination direction. Also, the side on which the printing layer 30 is formed with respect to the reflective layer 10 (the upper side on the paper surface in FIG. 1) is referred to as the upper side, and the opposite side (the lower side on the paper surface in FIG. 1) is referred to as the lower side. Also, viewing from the lamination direction is referred to as a plan view, and viewing in a cross-section along the lamination direction is referred to as a cross-sectional view.

[0030] The printing layer 30 may have an image portion that is visible when viewed from the lamination direction. The image portion may be such that the authenticity of the optical structure 1 can be verified visually by the image. That is, the image formed on the printing layer 30 may be made authenticatable.

[0031] The printing layer 30 has a diffusive reflectivity that reflects incident light isotropically at the reflection surface. A typical diffusive reflection is Lambertian reflection. It may also have specular reflectivity. Also, the printing layer 30 may be composed of a diffusive reflector. The printing layer 30 may be composed of a plurality of layers, particularly two layers. When the printing layer 30 is composed of two layers, the two layers may be in direct contact or may be stacked via a resin. As shown in FIG. 13 to be described later, when two printing layers 30 are disposed on both the upper and lower surfaces of the reflective layer 10, different images can be formed on each of the two printing layers 30. Thereby, when viewed from the lamination direction, an optical structure 1 can be obtained in which different images are observed on the front and back.

[0032] As an image on the printing layer 30, identifiers such as barcodes and two-dimensional codes can be formed. The image can be formed by a printed area and a non-printed area. In the printed area, a plurality of barcodes and two-dimensional codes can record digital data as codes. The digital data can be recorded as codes. Examples of the codes are barcodes and two-dimensional codes. An example of the two-dimensional code is a QR code (registered trademark). The identifier has, in a plan view, a white level area of the printing layer 30 that is a printed portion and a black level area sandwiched between the white level areas. The formed identifier can be authenticated using a barcode reader.

[0033] The image formed on the printing layer 30 can be perceived visually. Thereby, forgery prevention and aesthetic appearance can be improved. The above-described image may have a plurality of image portions. The image portion can display an image as a single entity or as a plurality of integrations.

[0034] The image can be a portrait, a motif of a landmark, art, a motif of nature, a geometric pattern, a sign, a symbol, an emblem, a coat of arms, or a single text or a combination thereof. The symbol and the emblem can be a motif of a flag, a shield, a sword, a spear, a crown, a star, a moon, a heart, a logo, a ribbon, a line, a flower, a leaf, a grain, a fruit, a bird, a wing, a fish, an arthropod, a mammal, a reptile, an amphibian, a legendary creature, a mythological god, or a mythological goddess.

[0035] The landmark can be a heritage, a relic, a historical building, a mountain, a valley, a rock, or a monument. Nature can be a living thing, a star, a moon, the sky, a mountain, a valley, or a rock. The living thing can be a flower, a leaf, a grain, a fruit, a bird, a wing, a fish, an arthropod, a mammal, a reptile, or an amphibian. The legendary creature can be a unicorn, a dragon, or a phoenix. These motifs can represent a symbol.

[0036] The symbol can represent a country, a region, a state, a group, a council, a treaty, an alliance, a union, or a pivot.

[0037] In this specification, in the optical structure 1, a first region can be formed in the printing layer 30. The outer shape of the first region when the optical structure 1 is observed in the stacking direction can be an intended shape. The intended shape can be a shape for verifying the authenticity of the optical structure 1 or a shape for identifying the optical structure 1.

[0038] In other words, the intended shape can be authenticated. Also, the intended shape can be identified. The intended shape can be a size visible to the naked eye or a size visible under a microscope. The intended shape can be observed by illuminating the optical structure 1 from the observer side.

[0039] The reflective layer 10 is a surface that anisotropically reflects incident light on the reflection surface. For example, it is a sheet on which a metal is vapor-deposited. Also, the reflective layer 10 may be composed of a reflector.

[0040] Note that the optical structure 1 may have a light-transmissive layer between each layer constituting the optical structure 1. The light-transmissive layer between each layer may be an adhesive layer that adheres the layers on both sides of that layer.

[0041] The main component of the reflective layer 10 can be an inorganic substance, an organic substance, or a mixture thereof. The inorganic substance can be a metal, a metal compound, or silicon oxide (glass). Examples of metals are aluminum, silver, tin, chromium, nickel, copper, and gold.

[0042] Examples of metal compounds are titanium oxide, aluminum oxide, and zinc sulfide. Metal compounds generally have a high refractive index. The organic substance can be a conductive polymer. Examples of conductive polymers can be polyacetylene and polyethylenedioxythiophene (PEDOT).

[0043] Also, when a barcode is printed on the printing layer 30 to form a black level region where reading by a barcode reader does not occur, it is desirable that the layer satisfies either or both of anisotropically reflecting incident light on the reflection surface or having a retroreflectance of incident light of 20% or less.

[0044] The reflective layer 10 can be formed by deposition or printing. For deposition, physical vapor deposition or chemical vapor deposition (CVD) can be applied. Alternatively, it may be an aluminum foil. The thickness of the aluminum foil can be 6 μm or more and 100 μm or less. As a packaging material, 6 μm or more and less than 15 μm is preferable, as a sealing material, 15 μm or more and less than 50 μm is preferable, and as a tray, 50 μm or more and 100 μm or less is preferable. The aluminum foil can be manufactured by thinly rolling an aluminum plate by rolling. Also, the surface of the aluminum foil may be coated with a transparent resin. The transparent resin coated on the aluminum foil can be the spacer layer 20.

[0045] The glossiness of the reflective layer 10 measured at 60° can be 40 or more. If the glossiness is high, when reading the code with a reader, it is easy to make the specular reflectance of the incident light 20% or less. Even if the reflectance is low, the code can be read with a reader, but the glossiness of the reflective layer 10 is reduced.

[0046] Physical vapor deposition may be vacuum evaporation or sputtering. The reflective layer 10 formed by physical vapor deposition can be made of a metal. The metal of the target in physical vapor deposition may be various metal targets with a purity of 4N or more. The material of the reflective layer 10 formed by physical vapor deposition can be aluminum, silver, gold, or copper. Also, the reflective layer formed by physical vapor deposition can be single-layer or multi-layer.

[0047] When forming by printing, depending on the printing method, offset ink, silk screen, letterpress ink, gravure ink, etc. can be used.

[0048] The ink can be resin ink, oil-based ink, water-based ink, etc. Also, depending on the difference in the drying method, for example, oxidation polymerization type ink, penetration drying type ink, evaporation drying type ink, ultraviolet curable ink, etc. can be used.

[0049] The ink can be pigment ink, dye ink, or a mixture thereof. An example of pigment ink is inorganic pigment ink. The inorganic pigment ink may be magnetic ink. The magnetic ink can form a pattern by magnetism. Since this pattern is unique, it is easy to increase the difficulty of forgery.

[0050] Examples of the dye ink are liquid crystal inks. Examples of the liquid crystal inks are cholesteric liquid crystal inks. Cholesteric liquid crystals reflect light of a specific wavelength. Therefore, they form a colored reflective layer. Also, the reflectance changes depending on the rotation direction of circular polarization or elliptical polarization. Further, a functional ink whose color changes according to the illumination angle or the observation angle may be used as the reflective layer.

[0051] Examples of such functional inks include, for example, Optical Variable Ink, Color Shift Ink, and Pearl Ink.

[0052] The scattering reflector of the printing layer 30 scatters and reflects the incident visible light. The main component of the scattering reflector can be an inorganic material. The inorganic material can be a white pigment, a colored material, or a functional ink. The white pigment can be a metal oxide, a metal compound, or silicon oxide. Also, organic dyes such as azo dyes, anthraquinone dyes, indigo dyes, sulfur dyes, and carbonium dyes may be mixed with the inorganic pigment.

[0053] Examples of the metal oxide are titanium oxide, zinc oxide, and lead oxide.

[0054] Examples of the metal compound are barium sulfate, zinc sulfide, cadmium sulfide (cadmium yellow), zinc chromate, etc. Metal compounds generally have a high refractive index. The colored material is a material that exhibits a color in the visible region and includes pigments, dyes, etc. The functional ink is a functional ink whose color changes according to the illumination angle or the observation angle and includes Optical Variable Ink, Color Shift Ink, Pearl Ink, etc.

[0055] The printing layer 30 can be formed by printing. The printing can be gravure printing, screen printing. Also, inkjet printing may be used. Further, it may be sublimation transfer printing or thermal transfer printing. This printing is particularly preferable as underprinting. Also, when printing on a curved surface, pad printing can be applied. Further, offset printing or flexographic printing may be used.

[0056] The screen line count of the undercoat printing screen printing can be, for example, 100 lines or more, 400 lines, preferably 200 to 350 lines. The line speed at this time can be, for example, 5 to 100 m / min. The line count in gravure printing can be, for example, 100 to 500 lines. The line speed at this time can be, for example, 50 to 500 m / min.

[0057] The viscosity of the ink can be, for example, 100 cp or more and 2000 cp or less. This viscosity can be measured with a kinematic viscometer. The solid content ratio can be the weight ratio of the ink including the solvent to the total amount of the ink vehicle and pigment, and can be 10 or more and 30 or less, and further may be 15 or more and 25 or less. The ratio of pigment to vehicle in the undercoat printing can be 1:3.75 or more and 1:6.25 or less.

[0058] The thickness of the single-layer printing layer 30 is preferably 700 nm or more and 500 μm or less.

[0059] When forming the printing layer 30 by printing, inks such as offset ink, silk screen, letterpress ink, intaglio ink, and gravure ink can be used according to the printing method. The ink can be resin ink, oil-based ink, water-based ink, etc.

[0060] Also, according to the difference in the drying method, for example, it can be oxidation polymerization type ink, penetration drying type ink, evaporation drying type ink, ultraviolet curable ink, etc. The ink can be pigment ink, dye ink, or a mixture thereof.

[0061] An example of the pigment ink can be magnetic ink. The magnetic ink can form a pattern by magnetism. Since this pattern is unique, it is easy to increase the difficulty of forgery.

[0062] Examples of the dye ink are infrared light-emitting ink, ultraviolet light-emitting ink, and liquid crystal ink. An example of the liquid crystal ink is cholesteric liquid crystal ink. Cholesteric liquid crystal reflects light of a specific wavelength. Therefore, it becomes a colored reflective layer.

[0063] In addition, the reflectance changes depending on the rotation direction of circularly polarized light or elliptically polarized light. Further, a functional ink whose color changes according to the illumination angle or the observation angle may be used as the reflective layer. Examples of such functional inks include optical variable ink, color shift ink, and pearl ink.

[0064] The printing layer 30 forms an identifier including a machine-readable code. The machine-readable code may be a barcode readable by a barcode reader.

[0065] The thickness of the printing layer 30 forming the barcode is preferably 1 μm or more and 500 μm or less. The area ratio of the printing area as a scattering reflector in the printing layer 30 forming the white level section of the code is preferably 65% to 100%. If this area ratio is 65%, reflection occurs more prominently than transmission of incident light. The printing area of the underprint can be a scattering reflector. The printing layer 30 can be the layer of the underprint. The underprint layer is usually a single layer.

[0066] The glossiness of the underprint may have a print of a product pattern, design, logo, crest, natural motif, geometric pattern, emblem, crest, or text alone or a combination thereof printed thereon in black, gray, or colored ink. Further, it may be covered with a transparent varnish as the outermost layer covering these prints.

[0067] Furthermore, if the thickness of the printing layer 30 is 1 μm or more, the retroreflectance of incident light can satisfy 80% or less and 40% or more. Thereby, a clear contrast between black and white can be obtained and authentication becomes possible.

[0068] When the printing layer 30 has two layers, the thickness is preferably 2 μm or more and 1 mm or less. The two-layer printing layer 30 can be different prints and deposits from each other. Also, the two-layer printing layer 30 can have one layer as a print and the other layer as a deposit.

[0069] The printing layer 30 may be partially removed by chemical etching. That is, the printing layer 30 may be partially formed.

[0070] The printing layer 30 may be partially removed by a laser.

[0071] Also, when the printing layer 30 has two layers and is partially formed, the outer shapes of the specular reflections of the specular reflectors included in the two layers of the printing layer 30 may overlap. In this case, the printing layer 30 displays an image formed by the outer shapes of the two specular reflection layers during transmission observation.

[0072] By partially removing the printing layer 30, the aesthetic appearance can be improved. The intended outer shape of the partially formed printing layer 30 can be a security motif. The security motif can be an authentication motif or a verification motif.

[0073] The security motif can be a line drawing, a geometric pattern, text, or calligraphy. An example of the geometric pattern is a guilloche.

[0074] An example of the text is microtext. Examples of calligraphy are Western calligraphy, Islamic calligraphy, Georgian calligraphy, Chinese calligraphy, Japanese calligraphy, Korean calligraphy, Philippine Suyat, Thai calligraphy, Indian Oriya script, and Nepalese calligraphy.

[0075] As described above, according to the present embodiment, it is possible to provide an optical structure capable of forming a code that is difficult to forge and that achieves both high readability and aesthetic appearance.

[0076] [Second Embodiment] The second embodiment of the present invention will be described with reference to FIGS. 2 to 7. In the following description, for components that are the same as those already described, the same reference numerals will be given and redundant descriptions will be omitted.

[0077] FIG. 2 is a cross-sectional view for conceptually explaining the structure of the optical structure 2 according to the second embodiment of the present invention. That is, the optical structure 2 is formed by sequentially laminating a reflective layer 10, an embossing layer 15, a spacer layer 20, a printing layer 30, and a protective layer 40.

[0078] The embossing layer 15 may form a relief structure. The surface having the relief structure can be a relief surface.

[0079] Also, an embossing layer 15 having a relief structure can be disposed between the spacer layer 20 and the printing layer 30.

[0080] These relief structures are constituted by the shape of the concavo-convex structure. The relief structure may be formed by transferring (embossing) the concavo-convex relief structure formed on the surface of a metal stamper to an object.

[0081] The relief structure has optical effects such as an optical diffraction effect, an antireflection effect, an isotropic or anisotropic scattering effect, a lens effect, and a polarization selective reflection effect. Due to this optical effect, authenticity can be verified visually. That is, the relief structure is visible.

[0082] Also, it can be verified visually. The printing layer 30 on the relief surface having the relief structure is also visible and can be verified. In other words, the printing layer 30 on the relief surface having the relief structure can also be verified visually for authenticity.

[0083] Thereby, an effect of preventing forgery and alteration is exhibited. Also, due to this optical effect, an aesthetic appearance can be provided. That is, due to this optical effect, the optical structure can have a visual effect.

[0084] By combining one or more relief structures having optical effects, the desired optical effect may be obtained. The regions having respective optical effects may be arranged in contact with each other, adjacent to each other, close to each other, at a fixed interval, alternately.

[0085] In this way, a relief surface having a relief structure with multiple optical effects can exhibit a complex visual effect, so it is effective in preventing forgery and alteration. Also, the aesthetic appearance of the optical structure 2 can be enhanced.

[0086] The relief structure has concave and convex portions, and imparts optical properties such as diffraction, light reflection suppression, isotropic or anisotropic light scattering, refraction, polarization / wavelength-selective reflection, transmission, and light reflection suppression to the optical structure 2.

[0087] As the relief structure, for example, a region of a diffraction grating structure may be provided with a pitch of 0.5 μm or more and 2 μm or less, and a depth of 0.05 μm or more and 0.5 μm or less. Thereby, the relief structure imparts the property of diffracting light to the optical structure 2.

[0088] As the relief structure, for example, a moth-eye structure or a deep grating structure may be provided with a pitch of 0.1 μm or more and 0.5 μm or less, and a depth of 0.25 μm or more and 0.75 μm or less. In this case, the relief structure imparts the property of light reflection suppression and polarization / wavelength-selective reflection, transmission, and light reflection suppression to the optical structure 2.

[0089] As the relief structure, for example, a region of an aperiodic linear or dot-like repeating structure may be provided with an average pitch of 0.5 μm or more and 3 μm or less, and a depth of 0.05 μm or more and 0.5 μm or less. Thereby, the relief structure imparts the property of emitting isotropic or anisotropic scattered light to the optical structure 2.

[0090] As the relief structure, a region having an average pitch greater than 3 μm and a structure deeper than 0.5 μm may be provided. Thereby, it becomes possible to have a refractive index different from that of an adjacent layer, and the relief structure imparts the property of refraction to the optical structure 2.

[0091] The relief structure may also include a relief surface (recording surface) disclosed in International Publication No. WO 2017 / 209113. That is, the relief surface in the present embodiment may have a phase angle recording region and a phase angle non-recording region, like the recording surface disclosed in International Publication No. WO 2017 / 209113.

[0092] Furthermore, in the relief surface, regions other than the phase angle recording region are phase angle non-recording regions. In one example, the phase angle non-recording region is a mirror surface.

[0093] Next, the positional relationship of each component will be described using the XYZ orthogonal coordinate system. Here, it is assumed that the relief surface is arranged along the XY plane.

[0094] When light is incident from a direction intersecting the relief surface, a reproduced image can be obtained by modulating the incident light with the relief surface. The reproduced image is an image of a plurality of reproduction points. The reproduction points are obtained at positions separated from the relief surface in the Z direction. The range in which the reproduced image in the viewing angle direction is reproduced when viewing the relief surface from a reproduction point of interest is called the viewing angle θ. In the following description, the viewing angle direction is the X direction or the Y direction.

[0095] On the relief surface, calculation element sections are respectively defined according to the viewing angle θ from each reproduction point where the reproduced image is reproduced. Thus, since the calculation element sections are defined independently of the phase angle recording region and the phase angle non-recording region, they usually overlap individually with the phase angle recording region and the phase angle non-recording region.

[0096] Also, there are a plurality of reproduction points. Therefore, the number of calculation element sections is the same as the number of reproduction points, corresponding to each of the plurality of reproduction points.

[0097] Further, the playback point is arranged at a distance from the relief surface. The distance of the playback point from the relief surface in the Z direction is preferably reproduced to be 5 mm or more and 25 mm or less. Note that the playback point may be reproduced on the observer side from the relief surface or on the side opposite to the observer of the relief surface. In either case, the distance of the playback point from the relief surface can be defined similarly.

[0098] The viewing angle θ from the playback point is defined by the following formula (1).

[0099] θ < (A / m) ····(1) Here, when (λ / 2d) ≤ 1, A = asin(λ / 2d), λ is the wavelength of light, d is the array pitch in the viewing angle direction of the unit block, and m is a real number of 3 or more. Specifically, this wavelength λ of light can be 555 nm, which is the maximum specific visual sensitivity of humans among visible light. The array pitch d can be the center-to-center distance of the unit blocks. The array pitch of the central unit block can be 10 nm or more and 200 nm or less.

[0100] The viewing angle θ is determined by the range in the X direction when looking at the relief surface from the playback point of interest, and is half of the angle 2θ formed by the minimum value Xmin in the X direction, the playback point of interest, and the maximum value Xmax in the X direction. Note that the X direction and the Y direction respectively correspond to the X coordinate axis and the Y coordinate axis of the Euclidean coordinates with one direction in which the relief surface extends as the X direction and the direction orthogonal to the X direction as the Y direction.

[0101] Note that the viewing angle θ when the viewing angle direction is the Y direction is defined in the same way. That is, the viewing angle θ is determined by the range in the Y direction when looking at the relief surface from the playback point of interest, and is half of the angle 2θ formed by the minimum value Ymin in the Y direction, the playback point of interest, and the maximum value Ymax in the Y direction. Therefore, the array pitch d of the unit block corresponds to the array pitch dx in the X direction of the unit block when the viewing angle direction is the X direction, and corresponds to the array pitch dy in the Y direction of the unit block 12 when the viewing angle direction is the Y direction.

[0102] For this reason, the calculation element section generally has a square or rectangular shape. However, the calculation element section may also be a polygon other than a quadrilateral, or a circle or an ellipse. Among polygons, in addition to squares and rectangles, hexagons are also suitable. When the calculation element section is other than a square or a rectangle, let the minimum value (lower limit value) in the X direction of the calculation element section be Xmin, and the maximum value (upper limit value) in the X direction of the calculation element section be Xmax. Similarly, let the minimum value in the Y direction of the calculation element section be Ymin, and the maximum value Ymax in the Y direction of the calculation element section 16.

[0103] When the shape of the unit block is a square or a rectangle, in reality, it becomes a rounded rectangle with rounded corners of the square or rectangle. Also, the unit blocks may be fused with adjacent unit blocks. In this case, as the shape of each unit block, it may be a rounded rectangle, but as the shape of the fused unit blocks, it does not become a rounded rectangle and is deformed, but even if it is deformed by fusion, the optical effect does not change.

[0104] The unit blocks are preferably arranged neatly. As a neat arrangement, it can be an arrangement at regular intervals within a certain range, an equidistant arrangement. Typical neat arrangements are a square arrangement and a hexagonal arrangement.

[0105] As can be seen from the above formula (1), the viewing angle θ is less than A. When light passes through this phase component and is diffracted, theoretically, diffraction exceeding A does not occur. Therefore, when performing hologram calculation using a computer, the calculation range may be limited with the viewing angle θ as the upper limit. In this way, limiting the calculation range will shorten the calculation time.

[0106] Also, even if the calculation is performed for a range exceeding the viewing angle θ, it only performs the calculation of diffraction that does not exist theoretically, so the result only contributes as noise. However, in the above calculation, the calculation for a range exceeding the viewing angle θ is not performed, so noise is not superimposed during the reproduction of the reproduced image at the reproduction point.

[0107] Both the phase angle recording area and the non-phase angle recording area include a plurality of unit blocks. For the unit blocks included in the area (overlapping area) that overlaps with the calculation element section among the phase angle recording areas, a computer calculates a phase angle based on the phase component, and the calculated phase angle is recorded in the corresponding unit block included in the overlapping area.

[0108] The relief surface of this embodiment is visible and verifiable. When the optical structure 2 having such a relief surface as a relief structure is inclined by a certain degree or more and observed from outside the range of the above-mentioned viewing angle θ, the reproduced image disappears due to the relief structure.

[0109] On the other hand, when the visible image formed on the printing layer 30 is a barcode, the barcode is in a state where it can be read by a barcode reader even under this observation condition (outside the range of the viewing angle θ).

[0110] Also, the above-mentioned reproduced image is reproduced only by a point light source. Therefore, under diffuse illumination, the reproduced image disappears. On the other hand, the barcode is in a state where the code can be read by a barcode reader even under this observation condition (outside the range of the viewing angle θ).

[0111] The viewing angle θ is preferably 5 degrees or more from the viewpoint of the visibility of the reproduced image, and preferably 15 degrees or less from the viewpoint of making the reproduction point disappear easily.

[0112] The optical properties of the optical structure 2 can be perceived visually. Thereby, the performance of preventing forgery and alteration and the aesthetic appearance can be improved. The above-mentioned relief structure may have a plurality of relief structure areas.

[0113] The relief structure area can display an image as a single unit or as a plurality of integrations. The image can be a portrait, a motif of a landmark, art, a motif of nature, a geometric pattern, a sign, a symbol, an emblem, a coat of arms, or a single text or a combination thereof.

[0114] Symbols and emblems can be composed of motifs of flags, shields, swords, spears, crowns, stars, moons, hearts, logos, ribbons, lines, flowers, leaves, grains, fruits, birds, wings, fish, arthropods, mammals, reptiles, amphibians, legendary creatures, mythological gods, and mythological goddesses.

[0115] Landmarks can be composed of heritage, ruins, historical buildings, mountains, valleys, rocks, and monuments.

[0116] Nature can be composed of living things, stars, moons, sky, mountains, valleys, and rocks. Living things can be composed of flowers, leaves, grains, fruits, birds, wings, fish, arthropods, mammals, reptiles, and amphibians.

[0117] Legendary creatures can be composed of unicorns, dragons, and phoenixes. These motifs can represent symbols. Symbols represent countries, regions, states, groups, councils, treaties, alliances, unions, and pivots.

[0118] The protective layer 40 is, for example, a layer containing a thermoplastic resin and a surface modifier. The thermoplastic resin of the protective layer 40 may be a resin having a glass transition temperature of 90°C or higher and 130°C or lower.

[0119] The thermoplastic resin can be any one of an acrylic resin, a polyester resin, a polyamide resin, any copolymer resin, any composite resin, or any composite resin of any copolymer resin.

[0120] The surface modifier may be a powder, a wax, or an oil. The powder may be a heat-resistant powder. The heat-resistant powder can be a silica powder, a polyethylene powder, a fluorine-based powder, or a silicone-based powder.

[0121] The wax can be paraffin wax, silicone, or carnauba wax. The oil may be silicone oil.

[0122] The embossing layer (not shown) has a relief structure on at least one of the surfaces. The embossing layer is formed of, for example, an ultraviolet curable resin, a thermoplastic resin, or a thermosetting resin.

[0123] The ultraviolet curable resin can be a monomer, oligomer, or polymer having an ethylenically unsaturated bond or an ethylenically unsaturated group, which is a cured resin.

[0124] Examples of the monomer having an ethylenically unsaturated bond or an ethylenically unsaturated group include 1,6 - hexanediol, neopentyl glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate.

[0125] Examples of the oligomer having an ethylenically unsaturated bond or an ethylenically unsaturated group include oligomers or co - oligomers of epoxy acrylate, urethane acrylate, and polyester acrylate.

[0126] Examples of the polymer include polymers or copolymers of urethane - modified acrylic and epoxy - modified acrylic.

[0127] Examples of the ultraviolet curable resin include any one of acrylic resin, acrylic acrylate resin, epoxy acrylate resin, urethane acrylate resin, polyester acrylate resin, ethylene methacrylate resin, any copolymer resin, any composite resin, and any composite resin of any copolymer resin.

[0128] The thickness of the embossing layer can be 1 μm or more and 25 μm or less.

[0129] When using a thermoplastic resin as the material for the embossing layer, it can be any one of an acrylic resin, an epoxy resin, a cellulose resin, a vinyl resin, any copolymer resin, any composite resin, or any composite resin of any copolymer resin.

[0130] The thermosetting resin of the embossing layer can be any one of a urethane resin, a melamine resin, an epoxy resin, a phenol resin, any copolymer resin, any composite resin, or any composite resin of any copolymer resin. The same materials can also be applied to the protective layer 40.

[0131] The embossing layer may be colored. It can be colored by adding a pigment or a dye to the resin of the embossing layer. The pigment can be an inorganic pigment or an organic pigment. Or the pigment can also be a fluorescent pigment, a pearl pigment, or a magnetic pigment. The dye can be a natural dye or a synthetic pigment. Or the dye can also be a fluorescent dye.

[0132] Note that the optical structure 2 may have a light-transmitting layer between each layer constituting the optical structure 2. The light-transmitting layer between each layer may be an adhesive layer that adheres the layers on both sides of that layer.

[0133] The spacer layer 20 has light-transmitting property or transparency. The required light-transmitting property or transparency of the spacer layer 20 may be at a level such that the light incident from the protective layer 40 side reaches the reflective layer 10 and the light reflected by the reflective layer 10 can pass through. The spacer layer 20 may be colored. The spacer layer 20 may be a layer that transmits visible and infrared laser beams.

[0134] The spacer layer 20 may be configured to be capable of laser writing a visible code. The material of the spacer layer 20 may be polycarbonate or polyester, which is resistant to heat during laser writing.

[0135] Moreover, a material having some light scattering properties can also be used for the spacer layer 20. In this case, the transmittance is preferably 40% or more, more preferably 60% or more, in the visible region from a wavelength of 380 nm to 780 nm. Typically, the transmittance at a wavelength of 1064 nm of the laser beam is preferably 30% or more.

[0136] As the material of the spacer layer 20, a polyolefin or a polymer having an aryl group can be used. The polyolefin and the polymer having an aryl group are light-transmitting or transparent polymers.

[0137] The polymer having an aryl group can be polycarbonate or polyethylene terephthalate. The polyolefin can be either polyethylene or polypropylene, their modified products, or their copolymers.

[0138] In addition, since the polyolefin has a simple main-chain structure and is thermally stable, there is little chemical change with a laser beam having a certain energy or less. Therefore, even when irradiated with a laser beam having the energy to remove the reflective layer 10, discoloration of the spacer layer 20 hardly occurs.

[0139] Furthermore, since either polyethylene or polypropylene, their modified products, or their copolymers are crystalline polymers, a certain amount of heat is required for the phase transition during melting, so there is little change with irradiation of a laser beam having a certain energy or less.

[0140] In addition, since the aromatic hydrocarbon of the aryl group forms a resonance hybrid and thus has excellent heat resistance, deformation and the like when irradiated with a laser beam having the energy to remove the reflective layer 10 are easily suppressed.

[0141] On the one hand, since aromatic hydrocarbons have a high ratio of carbon in their molecules, they are prone to carbonization. When carbonized with sufficient heat, they can develop a sufficiently black color even in a thin layer. Therefore, when the material of the spacer layer 20 is a polymer having an aryl group, when the irradiation energy of the laser beam is sufficiently high, the reflective layer 10 can be removed and the spacer layer 20 can be carbonized to develop a black color.

[0142] Note that the reflective layer 10 in the carbonized portion of the spacer layer 20 does not necessarily need to be removed. By separating the focus of the laser beam from the reflective layer 10 (although it depends on the irradiation energy and depth of focus of the laser beam, it is 50 μm or more and 350 μm or less), or by providing the reflective layer 10 after carbonizing the spacer layer 20, it is also possible to carbonize the spacer layer 20 without removing the reflective layer 10 in the carbonized portion.

[0143] This carbonized removal region is difficult to read with a barcode reader while having excellent visibility. Therefore, a visible code can be recorded. The visible code can be formed by a sequence of any one of symbols, alphabets, numbers, or a combination thereof.

[0144] This enables both efficient processing by a barcode reader and visual confirmation of the code. Tampering can be prevented by also recording the visible code of this carbonized removal region in the hologram portion.

[0145] In addition, this visible code can include part or all of the information of the code data recorded as a barcode. Also, the visible code may be such that the correspondence with the barcode is stored in a table of a data server.

[0146] Also, a code obtained by encrypting the data recorded in the barcode may be recorded. When including part of the information of the code data recorded as a barcode, a hash can be used. This hash may be an encryption hash.

[0147] By means of a hash, even a short code can be associated with the identifier of a barcode read by a reading machine and large data. Also, by using an encrypted code, genuine verification and data concealment can be achieved.

[0148] Also, an adhesive layer mainly composed of an acrylic resin may be provided adjacent to the spacer layer 20. Although the acrylic resin has low heat resistance, its thermal decomposition is of the depolymerization type, so as long as it has a certain molecular weight, the molecular structure can remain after irradiation with a laser beam and its performance can be maintained. The molecular weight of the acrylic resin is preferably 100,000 or more.

[0149] Also, when the molecular weight is large, the glass transition temperature also rises. Therefore, if the glass transition temperature is at a certain level or higher, generally the molecular weight is large. Thus, for an acrylic resin with a glass transition temperature of 40 degrees or more, even if irradiated with a laser beam to a degree sufficient to remove the reflective layer with a large enough molecular weight, it is easy to maintain the adhesion of the adhesive. The thickness of the adhesive layer can be 0.1 μm or more and 10 μm or less.

[0150] The material of the spacer layer 20 may be a polymer. When the spacer layer 20 is formed of the same type of material as the scattering reflective layer, it is easy to integrally bond the two by thermal fusion.

[0151] The thickness of the spacer layer 20 preferably ranges from 25 μm to 200 μm. If it is 25 μm or more, it is easy to prevent damage to the reflective layer 10. If it is 200 μm or less, it is difficult to perceive the protrusion of the optical structure 1 during lamination or embedding, and it is easy to obtain the flexibility of the spacer layer 20.

[0152] The protective layer 40 has the same light transmittance or transparency as the spacer layer 20, protects the planar shape of the printing layer 30, and maintains the state in which the above-mentioned code is machine-readable.

[0153] The protective layer 40 can be formed of various resins. The resin of the protective layer 40 can be a polycarbonate resin or an acrylic resin. The resin of the protective layer 40 can be a thermoplastic resin or a curable resin. When the protective layer 40 is formed of the same type of material as the spacer layer 20, it is easy to integrally bond all the layers by thermal fusion.

[0154] The difference in softening temperature between the protective layer 40 and the spacer layer 20 may be within 30 °C. Thereby, it is easy to integrally bond each layer by thermal fusion. The thickness of the protective layer 40 is preferably 50 μm or more and 400 μm or less.

[0155] FIG. 3 is a plan view for conceptually explaining an optical structure according to a second embodiment of the present invention.

[0156] The plan view shown in FIG. 3 is an example of a plan view of the optical structure 2 viewed from the protective layer 40 side in the stacking direction.

[0157] In this example, a visible code 51 formed by partially carbonizing the spacer layer 20 and a machine-readable code formed by the arrangement combination of the data of the visible code 51 formed by the printing layer 30, a printed white level region RW, and a black level region RB sandwiched between the white level regions RW, that is, a barcode 52 are formed as individual information recording (image information recording) 50.

[0158] The barcode 52 may include numbers or the like indicating an identification code at the lower part of a plurality of bars.

[0159] In this way, an identification code can be recorded in the individual information recording 50. This optical structure 1 can be a security pass.

[0160] Further, the printing layer 30 may be a brittle structure that breaks during peeling. Thereby, it is possible to make it more difficult to falsify the optical structure 2.

[0161] In FIG. 3, a visible code 51 and a barcode 52 are formed in the first region of the printing layer 30. Also, in FIG. 3, although the visible code 51 and the barcode 52 are formed, only the barcode 52 may be used.

[0162] Also, the visible code 51 and the barcode 52 can be identification codes. Also, the identification code of the barcode 52 may be a product code or a serial number.

[0163] In this case, the optical structure 1 can be a product tag. Also, the optical structure 1 may be a gift card.

[0164] In this case, the visible code 51 can be a claim code, and the identification code of the barcode 52 can be a serial number. This visible code may also be a code in which the spacer layer 20 is carbonized and recorded with a laser beam.

[0165] The individual information to be recorded can be a biometric identifier, a code, personal data, a symbol, or a combination thereof. Examples of biometric identifiers are a face image, a fingerprint, a signature, a walking motion, a voiceprint, an iris, and a vein pattern.

[0166] Examples of personal data are a name, a country name, and a country code. The optical structure 2 has a iridescent, white, or metallic appearance by reflection. The face image has an iridescent, white, or metallic appearance by reflection. The barcode 52 has an iridescent, white, or metallic appearance by reflection.

[0167] This iridescent, white, or metallic appearance may be switched according to the observation conditions. Also, the optical structure 2 may have a region where an iridescent color appears, a region where an interference color appears, and a region where a metallic luster appears.

[0168] (Manufacturing method of the optical structure 2) Next, with reference to FIGS. 4 and 5, a method for manufacturing the optical structure 2 will be described.

[0169] FIG. 4 and FIG. 5 are diagrams for explaining a process during the manufacture of the optical structure according to the second embodiment of the present invention.

[0170] FIG. 4 shows a pre-structure 2A in which a printing layer 30 is laminated on a spacer layer 20. The transfer of the printing layer 30 may use thermal transfer, 3D printer, screen printing, inkjet printing, or gravure printing.

[0171] FIG. 5 shows an optical structure 2 formed by adhering a protective layer 40 covering the printing layer 30 to the pre-structure 2A shown in FIG. 4. The adhesion of the protective layer 40 can be performed by pressure bonding with heat or adhesion using an adhesive layer.

[0172] Next, with reference to FIGS. 6 and 7, the behavior of light irradiated from the protective layer 40 side to the completed optical structure 2 will be described.

[0173] FIG. 6 is a diagram for explaining the behavior of light incident on the optical structure 2.

[0174] FIG. 7 is a diagram for explaining the behavior of light incident on the optical structure 2.

[0175] As shown in FIG. 6, the light L1 irradiated on the printing layer 30 is diffusely reflected. As a result, a part L1a of the incident light is retroreflected and returns in the incident direction. On the other hand, as shown in FIG. 7, the light L2 incident on the portion where the diffuser of the printing layer 30 does not exist passes through the spacer layer 20 and reaches the reflective layer 10, and is specularly reflected. As a result, the light L2 incident on the portion where the diffuser of the printing layer 30 does not exist is reflected mainly in the specular reflection direction different from the incident direction.

[0176] Therefore, among the light irradiated from the barcode reader, the light hitting the reflective layer 10 is not received by the barcode reader, and a part of the light hitting the printing layer 30 returns to the reader and is received.

[0177] As a result, the reader can detect the area where the printing layer 30 exists as a high signal level area and the area where the scattering reflector of the printing layer 30 does not exist as a low signal level area.

[0178] As a result, in the visible code 51 and barcode 52 (i.e., the first area), the area corresponding to the white part (the area recognized as white by the reader) is the area where the printing layer 30 exists, and the area corresponding to the black part (the area recognized as black by the reader) is distinguished from the area where the printing layer 30 does not exist, so that the individual information record 50 can be formed.

[0179] The individual information record 50 can be made visible by scattered reflection. Also, the individual information record 50 can be made machine-readable by scattered reflection.

[0180] The width of each area in the direction intersecting the longitudinal direction of the white level area RW and the black level area RB (the depth direction in FIGS. 7 and 8) may correspond to the recorded information of the barcode 52.

[0181] The standard size of the width of 1 module, which is the recording unit of the bar of the barcode, is defined as 0.33 mm. In the JAN standard barcode, the width of 1 module is from 0.15 times to 2.1 times the standard size, and in JIS X0507, the range from 0.8 times to 2.0 times is recommended as the width.

[0182] Therefore, the width of 1 module, which is the recording unit of the barcode 52, preferably ranges from 33 μm to 700 μm. That is, the minimum width of the bar of the barcode 52 (the minimum width of each area in the direction intersecting the longitudinal direction of the white level area RW and the black level area RB) can be 33 μm or more.

[0183] Also, the maximum length of the barcode 52 (the maximum value of the length in the longitudinal direction of the white level area RW and the black level area RB) is mainly limited by the barcode reader, and it can be read by a standard barcode reader if it is 10 cm or less.

[0184] Also, from the perspective of reducing reading errors, the maximum length of the barcode 52 is preferably 6 mm or less.

[0185] In the first region, a plurality of white level regions RW and a plurality of black level regions RB sandwiched between two adjacent white level regions RW in the X direction are formed. In this way, the barcode 52 encoding data such as the owner data of the visible code 51 can be formed by the alternately arranged white level regions RW and black level regions RB. Also, a product identification code can be recorded on the barcode.

[0186] As described above, in the optical structure 2 of the present embodiment, the individual information record 50 can be formed by controlling the printing width of the printing layer 30. The individual information record 50 is covered by the protective layer 40, and it is difficult to rearrange the material of the printing layer 30. That is, it is difficult to falsify the individual information record 50 recorded in the printing layer 30.

[0187] As a result, the individual information record 50 of the optical structure 2 has a high forgery difficulty. Therefore, the optical structure 2 in which the individual information record 50 is formed has high security, unlike the code printed on paper.

[0188] Also, the formed individual information record 50 has iridescence, whiteness, and metallic luster and is excellent in aesthetics. Also, the individual information record 50 can be an identifier including a readable code due to the difference in reflectivity between the white level region RW and the black level region RB. Therefore, the optical structure 2 in which the individual information record 50 is formed can resolve the conflict between aesthetics and readability.

[0189] A product identification code can be recorded on the barcode as an identifier including a readable code. The product identification code can be a JAN code, an EAN code, or a U.P.C. Also, a QR code can be formed as a two-dimensional code, and a URL can be recorded as an identifier including a readable code in the QR code.

[0190] As described above, according to the present embodiment, it is possible to provide an optical structure capable of forming a code that achieves both high readability and aesthetics in a reader. Further, forgery is difficult by using special processing or materials for the reflective layer 10 or printing, and an optical structure can be provided. [Third Embodiment] The third embodiment of the present invention will be described with reference to FIGS. 8 to 9. In the following description, components that are the same as those already described will be denoted by the same reference numerals, and redundant descriptions will be omitted.

[0191] FIG. 8 is a plan view showing an example of an optical structure according to the third embodiment of the present invention.

[0192] FIG. 8 shows a plan view of a card 101 as an example of the optical structure according to the present embodiment. The card 101 includes a first area 102 in which individual information record 50 is formed by printing, and a second area 103 in which text and face images are written by a laser beam.

[0193] An identifier including a machine-readable code (for example, barcode 52 readable by a barcode reader) is formed in the first area 102.

[0194] The text and face images in the second area 103 are visible. The text and face images in the second area 103 can be an identifier. The text and face images in the second area 103 can be individual information. The text and face images in the second area 103 can be the card owner information.

[0195] Further, the card 101 can be applied to one page of a booklet. Examples of booklets are passport booklets and visa booklets.

[0196] FIG. 9 is a schematic cross-sectional view for conceptually explaining the cross-sectional structure taken along line I-I of FIG. 8.

[0197] As shown in FIG. 9, the card 101 includes a spacer layer 105 instead of the spacer layer 20 on the white core layer 106. The material of the spacer layer 105 is a polymer having an aryl group, and a visible code can be written by irradiating a laser beam.

[0198] The polymer having an aryl group is the same as the polymer having an aryl group described in the first embodiment. That is, the spacer layer 105 is configured to be capable of laser writing a visible code. The thickness of the spacer layer 105 is preferably 50 μm or more and 400 μm or less.

[0199] In the first region 102 of the card 101 shown in FIG. 8, as shown on the right side of FIG. 9, a transfer foil 200 provided with a printing layer 30 is disposed between the spacer layer 105 and the protective layer 40. On the other hand, in the second region 103, as shown on the left side of FIG. 9, the protective layer 40 is located on the spacer layer 105 and the printing layer 30 does not exist.

[0200] As shown in FIG. 9, the transfer foil 200 includes a release layer 201, a printing layer 30 formed under the release layer 201, an embossing layer 202 formed under the printing layer 30, a reflective layer 10 formed under the embossing layer 202, and an adhesive layer 203 that is bonded under the reflective layer 10 and on the spacer layer 105.

[0201] The adhesive layer 203 is adhered to the reflective layer 10 on the upper surface and the spacer layer 105 on the lower surface.

[0202] Note that an anchor layer (not shown) may be provided at an arbitrary position between the printing layer 30 and the adhesive layer 203. Further, a mask layer (not shown) may be provided at an arbitrary position between the anchor layer and the printing layer 30.

[0203] The embossing layer 202 is formed of a resin or the like and can have an optical relief including fine irregularities on the surface on the adhesive layer 203 side. The relief structure of the embossing layer 202 is the same as the relief structure described in the first embodiment.

[0204] As described above, the adhesive layer 203 of the transfer foil 200 can be bonded to the spacer layer 105. In this case, in the stacking direction, the embossing layer 202 is disposed between the protective layer 40 and the printing layer 30, and the release layer 201 can be formed with the protective layer 40.

[0205] Alternatively, the adhesive layer 203 of the transfer foil 200 may be bonded to the protective layer 40. In this case, in the stacking direction, the embossing layer 202 is disposed between the spacer layer 105 and the printing layer 30.

[0206] With the above configuration, the transfer foil 200 exhibits a predetermined optical effect such as a hologram or a diffraction grating.

[0207] (Method for manufacturing the card 101) Next, a method for manufacturing the card 101 will be described.

[0208] To manufacture the card 101, first, the transfer foil 200 is produced.

[0209] The transfer foil 200 is formed by laminating a release layer 201, a printing layer 30, an embossing layer 202, a reflective layer 10, and an adhesive layer 203 in this order on a plastic film (not shown).

[0210] Next, the card 101 is formed. When forming the card 101, the plastic film and the transfer foil 200 are disposed with the adhesive layer 203 facing the card base material on the card base material provided with the white core layer 106 and the spacer layer 105.

[0211] After applying heat and pressure to the transfer foil 200 from above the plastic film and then peeling off the plastic film, the transfer foil 200 is joined to the card base material.

[0212] Thereafter, when the card base material and the transfer foil 200 are covered with a plastic film to be the protective layer 40 and laminated by applying heat and pressure, a card 101 having a first region 102 and a second region 103 can be manufactured as illustrated in FIG. 8.

[0213] The release layer 201 may be colored. It can be colored by adding a pigment or a dye to the resin of the release layer 201. The pigment can be an inorganic pigment, an organic pigment, or a mixture of an inorganic pigment and an organic pigment. The pigment may be a fluorescent pigment, a pearl pigment, a magnetic pigment alone, a blend of the same kind, a mixture of different kinds, or a mixture of a blend of different kinds and the same kind.

[0214] The dye can be a natural dye, a synthetic dye, or a mixture of a natural dye and a synthetic dye. The dye may be a fluorescent dye.

[0215] The release layer 201 can be formed by printing or coating on a plastic film. The coating can be a gravure coat, a microgravure coat, or a die coat.

[0216] The printing can be gravure printing or screen printing. From the viewpoint of processability, the thickness of the plastic film can be 10 μm or more and 50 μm or less. The thickness of the release layer 201 is preferably 0.5 μm or more and 5 μm or less.

[0217] The release layer 201 can receive the printing layer 30. The release layer 201 may mainly contain an acrylic resin. The acrylic resin easily receives the printing layer 30. A printed body with an OVD part (optically variable device) having a release layer 201 capable of receiving the printing layer 30 can be printed integrally.

[0218] Immediately after manufacturing, no information is written in the second region 103 of the card 101. By irradiating the second region 103 with a laser beam, the spacer layer 105 is carbonized to form a laser mark 105a, and information (laser mark) 105a can be written.

[0219] The information written as a laser mark may be personal data, a biometric identifier, or a code. An example of a biometric identifier is a face image.

[0220] In the printing layer 30 of the first region 102 of the card 101, white level regions RW and black level regions RB can be formed in the same manner as the printing layer 30 of the first embodiment. Thereby, the card 101 according to the present embodiment exhibits the same effects as the optical structure 1 according to the first embodiment.

[0221] Furthermore, by combining the individual information record 50 written in the first region 102, the information written in the second region 103, and the optical effect exhibited by the transfer foil 200, the security can be further enhanced.

[0222] Also, in the card 101, the printing layer 30 in which the individual information record 50 is formed is covered with the protective layer 40, making it difficult to forge.

[0223] Note that the first region 102 in the present embodiment is not limited to the configuration including the transfer foil 200. For example, when the optical effect by the embossing layer 202 is not given to the first region 102, the printing layer 30 may be formed only in the portion that is the first region 102, and an identifier may be formed in the same procedure as the first embodiment.

[0224] As described above, according to the present embodiment, it is possible to provide an optical structure and a method for manufacturing the same that are difficult to forge and can realize both high readability and aesthetics.

[0225] [Fourth Embodiment] The fourth embodiment of the present invention will be described with reference to FIG. 10. In the following description, for components that are common to those already described, the same reference numerals will be used and duplicate descriptions will be omitted.

[0226] FIG. 10 is a plan view showing one application example of the optical structure according to the fourth embodiment of the present invention.

[0227] As shown in FIGS. 10(a) and 10(b), the optical structure 400 according to this embodiment has a reflective layer 401 having specular reflectivity and a plurality of printed light color level regions 402 disposed on at least a part of the reflective layer 401, and has a machine-readable code such as a barcode 404 formed by a combination of the plurality of light color level regions 402.

[0228] FIGS. 10(a) and 10(b) show an example of the optical structure 400 in which a light-colored barcode 404 such as white and pink is formed on the surface of a product used as the reflective layer 401, and FIG. 10(c) shows the corresponding prior art.

[0229] When the surface of a product is used as the reflective layer 401, the surface of the product has gloss, such as a mirror layer. Thus, products whose surfaces can be used as the reflective layer 401 include, but are not limited to, for example, cards using vapor-deposited paper, book covers, packaging labels, and the like.

[0230] Even if the barcode 404 is disposed on the reflective layer 401 having gloss, a barcode formed in black cannot be read.

[0231] Therefore, in the prior art, as shown in FIG. 10(c), a sticker 415 on which an ink-colored, that is, black barcode 414 is printed is attached to the product 420. However, this may cause a sense of incongruity in terms of appearance and design, and there is a risk of damaging the brand image of the product 420.

[0232] However, a barcode 404 formed in white or a light color can be read. Therefore, in the optical structure according to this embodiment, the barcode 404 is formed by combining the light color level regions 402.

[0233] As the color of the light - level area 402 that forms the barcode 404, white is preferable as illustrated in FIG. 10(a). Also, as illustrated in FIG. 10(b), a pink color is also possible. By forming the barcode 404 with a light color such as white or pink in this way, it becomes possible to read the code information of the barcode 404 even from a shiny surface.

[0234] In particular, the examples shown in FIGS. 10(a) and 10(b) are examples in which the barcode 404 is formed in the same color as the background printing 406 of the product pattern.

[0235] As can be seen from FIGS. 10(a) and 10(b), such a barcode 404 looks integrated with the product pattern, has no unnaturalness due to the printing of the barcode 404, and does not damage the brand image of the product.

[0236] As described above, according to the present embodiment, an optical structure and a method for manufacturing the same that can be read even when disposed on a shiny surface and do not give a sense of incongruity in terms of appearance and design, preferably forming a barcode with white or a light color used in products, can be provided.

[0237] [Fifth Embodiment] The fifth embodiment of the present invention will be described.

[0238] For example, during the Christmas sales season, alcoholic beverages such as champagne are packaged and sold in packages made of shiny silver - vapor - deposited paper. As also described in the fourth embodiment, even if a black barcode is printed on the shiny vapor - deposited paper, the information of the barcode cannot be read.

[0239] Therefore, conventionally, as described with reference to FIG. 10(c) in the fourth embodiment, a sticker 415 with a barcode 414 printed in ink, that is, black, is attached to the package.

[0240] However, since the work of attaching the seal 415 is usually performed manually, the work burden increases. Also, because it is a manual operation, there is a risk that it may be attached unevenly, and in that case, the appearance will be poor.

[0241] Also, for example, in the case of Christmas products, where white, green, and red are the bases, when a seal 415 with a barcode 414 printed in black ink (black color) is attached to the package, the impression of the Christmas products is significantly impaired.

[0242] Furthermore, since the work of attaching the seal 415 is a work separate from the printing process, there is also a risk of a large amount of rework due to forgetting to attach the seal 415 during the manufacture of the product.

[0243] The optical structure according to this embodiment can solve such problems.

[0244] The optical structure according to the fifth embodiment of the present invention will be described with reference to FIG. 11. In the following description, for components that are the same as those already described, the same reference numerals will be used and duplicate descriptions will be omitted.

[0245] FIG. 11 is a perspective view showing an application example of the optical structure according to the fifth embodiment of the present invention.

[0246] The optical structure 500 shown in FIG. 11 is an example realized using a package for alcoholic beverages such as champagne.

[0247] The optical structure 500 has a machine-readable code such as a barcode 503 formed by utilizing the background color of the product 501 which is the package and the color of the base of the label 502 covering the product 501.

[0248] The barcode 503 is formed by a combination of a plurality of light color level regions 504 formed with one of the background color of the product 501 or the color of the base of the label 502 and a plurality of non-light color level regions 505 formed with the other of the background color of the product 501 or the color of the base of the label 502.

[0249] In the example shown in FIG. 11, the product 501 is a silver package that covers a bottle of liquor such as champagne. The label 502 is made of a light-shielding barrier film laminated on the product 501, and the base is white.

[0250] The barcode 503 is formed without using ink, with the silver background color as the non-light color level area 505 and the base of the label as the light color level area 504.

[0251] In this way, the barcode 503 is formed on the product 501 by utilizing the background color of the product 501 which is the package and the color of the base of the label 502 that covers the product 501.

[0252] Since this barcode 503 is machine-readable even if the product 501 has gloss, there is no need to attach a seal 415 printed with a black barcode 414 in ink to the product 501.

[0253] In this way, it is possible to reliably provide a machine-readable barcode 503 to the product 501 without spoiling the Christmas atmosphere.

[0254] According to such an optical structure 500 according to the present embodiment, the following operational effects can be achieved.

[0255] As described above, according to the present embodiment, it is possible to provide an optical structure and a method for manufacturing the same that can form a code readable from a glossy surface.

[0256] Next, examples of the optical structure of the present invention will be further described using comparative examples. In the following description, unless otherwise specified, "parts" means parts by mass.

[0257] [Example 1] Example 1 corresponds to the first embodiment. As shown in FIG. 1, the optical structure 1 has a reflective layer 10 and a printing layer 30.

[0258] In the optical structure 1 of Example 1, the materials of the reflective layer 10 and the printing layer 30 are as shown below.

[0259] Reflective layer 10: Aluminum vapor deposition film (PET, thickness 28 μm, Al vapor deposition), Printing layer 30: White inorganic pigment (weight ratio 1:5 = titanium oxide: ink solvent, Toyo Ink SS8 - 000).

[0260] (Fabrication of the optical structure 1) FIG. 12 is a top view showing the optical structure created according to Example 1 of the present invention.

[0261] To create the optical structure 1, a white inorganic pigment (titanium oxide) that becomes the printing layer 30 was transferred onto the reflective layer 10 by screen printing with a thickness of 50 μm and dried to form a scattering reflective layer. As shown in FIG. 12, the optical structure 1 of Example 1 having the printing layer 30 on the reflective layer 10 could be fabricated.

[0262] In the optical structure 1 shown in FIG. 12, the barcode 52 printed on the printing layer 30 as shown in the region K was scanned with a reader.

[0263] FIGS. 13 and 14 are diagrams showing the scan results of the barcode 52. In FIGS. 13 and 14, the viewing angles from the reader are different. FIG. 13 shows the result of scanning the barcode 52 obliquely with the reader, and FIG. 14 shows the result of scanning the barcode 52 almost directly from the front with the reader.

[0264] From the reading results exemplified in FIGS. 13 and 14, it was found that information can be obtained if the barcode 52 is read with the reader at an inclination of 20° or more and 80° or less from the normal of the structure surface.

[0265] [Example 2] In Example 2, the material of the printing layer 30 was a white ink containing a titanium oxide pigment (weight ratio 1:25, TiO2:SSS WAC varnish (acrylic resin) = 1 g:25 g by weight (TiO2 is 3% in the ink)), and an optical structure 1 having the same configuration as in Example 1 was produced.

[0266] When a code was formed on the printing layer 30 made of such a white ink by metal vapor deposition, the QR code was somewhat inferior in readability but readable, and the barcode was readable without problems. Probably, the barcode would be readable even if the metal vapor deposition was transparent vapor deposition.

[0267] Here, considering that the solid content ratio of the SSS WAC varnish is 15 to 25%, it is considered that TiO2:medium = 1 g:3.75 to 6.25 g in terms of the solid content ratio is within the readable range.

[0268] As described above, the best mode for carrying out the present invention has been described with reference to the accompanying drawings. However, the scope of the present disclosure is not limited to the illustrated and described embodiments, and can include all embodiments that bring about equivalent effects to those intended by the present invention. Furthermore, the scope of the present disclosure is not limited to the features of the invention defined by the claims, and includes all the disclosed features and any combinations of those features.

[0269] For example, as shown in the cross-sectional view of FIG. 15, by joining two optical structures according to any embodiment with their respective reflective layers 10 facing each other, an optical structure 301 having individual information records 50A and 50B on both sides can be formed.

[0270] In particular, FIG. 15 shows an example in which the optical structure 1A and the optical structure 1B having the same structure are joined, but the structures of the optical structures to be joined may be different.

[0271] Also, the identifier is not limited to the barcode 52 described above, and may be, for example, a two-dimensional code or the like.

[0272] The terms "part", "element", "pixel", "cell", "segment", "unit", "display body", and "article" as used in this disclosure are physical entities. A physical entity can refer to a material form or a spatial form surrounded by matter. A physical entity can form a structure. A structure can have a specific function. A combination of structures with specific functions can exhibit a synergistic effect through the combination of the functions of each structure.

[0273] Also, the terms used in this disclosure and especially within the scope of the appended claims (e.g., the body of the appended claims) are generally intended as "open" terms (e.g., the term "comprising" should be interpreted as "at least comprising", and the term "including" should be interpreted as "including but not limited to", etc.).

[0274] Furthermore, when interpreting terms, configurations, features, aspects, and embodiments, reference should be made to the drawings as necessary. Matters that can be directly and unambiguously derived from the drawings should, like the text, serve as a basis for correction.

[0275] Furthermore, when a specific number of introduced claim descriptions is intended, such intention is explicitly stated in the claim, and if there is no such description, such intention does not exist. For example, for the purpose of aiding understanding, the following appended claims include the use of introductory phrases such as "at least one" and "one or more" and can introduce a listing of claims. However, the use of such phrases should not be interpreted as limiting the embodiments to only those including such a description.

[0276] The introductory phrases "one or more" or "at least one" should be interpreted as meaning "one" or "one or more". The same applies to the use of definite articles used to introduce claim descriptions.

Description of Reference Numerals

[0277] 1, 2 Optical structures 2A, 2B Optical structures (pre-structures) 10 Reflective layer 15 Embossed layer 20 Spacer layer 30 Printing layer 40 Protective layer 50 Individual information recording 51 Visible code 52 Barcode 101 Card 102 First region 103 Second region 105 Spacer layer 106 White core layer 200 Transfer foil 201 Release layer 202 Embossed layer 203 Adhesive layer 301 Optical structure 400 Optical structure 401 Reflective layer 402 Light level region 404 Barcode 406 Underprinting 414 Barcode 415 Seal 420 Product 500 Optical structure 501 Product 502 Label 503 Barcode 504 Light level region

Claims

**Claim 1**: An optical structure formed by joining two optical structures by bonding their respective reflective layers to each other, wherein: each of the two optical structures comprises: a reflective layer having specular reflectivity; a printed layer as a diffusive reflector having diffusive reflectivity, laminated on at least a part of the reflective layer; a spacer layer having translucency or transparency, provided between the printed layer and the reflective layer; an image portion recognizable when viewed in the lamination direction is formed in the printed layer; the image portion has a printed light-color level region and a non-light-color level region sandwiched between the light-color level regions, the optical structure. **Claim 2**: The optical structure according to claim 1, wherein at least one of the two optical structures includes a protective layer having translucency or transparency that covers the printed layer. **Claim 3**: The optical structure according to claim 2, wherein at least one of the two optical structures further includes an embossed layer having an uneven structure between the spacer layer and the reflective layer or between the spacer layer and the printed layer. **Claim 4**: The optical structure according to claim 1, wherein the non-light-color level region is a black level region. **Claim 5**: An optical structure having a reflective layer with metallic luster and a plurality of printed light-color level regions disposed on at least a part of the reflective layer, and a machine-readable code formed by a combination of the plurality of light-color level regions is disposed. **Claim 6**: The optical structure according to claim 1, wherein the reflective layer is a mirror layer. **Claim 7**: The optical structure according to claim 6, wherein the reflective layer is a vapor deposition layer. **Claim 8**: The optical structure according to claim 1, wherein the light-color level region is a white level region. **Claim 9**: Prepare a reflective layer having metallic luster, laminate a spacer layer having translucency or transparency on the reflective layer, laminate a printed layer having an image portion with a machine-readable code formed by a light-color level region which is a printed portion and a region having the metallic luster sandwiched between the light-color level regions on at least a part of the spacer layer, and cover the spacer layer and the printed layer with a protective layer to manufacture an optical structure. **Claim 10**: A method of forming a machine-readable code using the ground color of a product and the color of the base of a label covering the product, comprising: forming a plurality of light-color level regions with the color of the base; forming a plurality of non-light-color level regions with the ground color. ​ ​ ​ ​ ​ Forming the machine-readable code by combining the plurality of light-level regions. Code formation method.

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