Optical structure

Abstract

To provide an optical structure capable of forming a code which is difficult to counterfeit and has both high readability and aesthetic appeal.SOLUTION: In an optical structure of the present invention, a spacer layer that is translucent or transparent is laminated on a reflective layer reflecting incident light specularly, a print layer having an image portion with a machine-readable code formed by a light-colored level area that is a printed portion and a non-light-colored level area sandwiched between the light-colored level areas is laminated on at least a part of the spacer layer, and the spacer layer and the print layer are covered with a protective layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to optical structures. [Background technology]

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

[0003] Barcodes are used not only on paper but also on various screens such as LCD screens and glass, where the patterns are displayed and the codes are read by machines. In addition, if the object can be decorated, the convenience and appearance of the object can be improved.

[0004] Therefore, Japanese Patent Application Laid-Open No. 2002-192867 proposes a method of incorporating an optical diffraction effect into the code. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2002-192867 [Patent Document 2] International Publication No. 2017 / 209113 Summary of the Invention [Problem to be solved by the invention]

[0006] However, conventional technologies have limitations on the layer structure of the optical element, and because the code is made of metal, it has a poor appearance. In addition, because the code is black, it cannot be read from a glossy surface.

[0007] Additionally, while black-and-white barcodes and two-dimensional codes are highly convenient because anyone can easily print them with a printer, they can also be easily counterfeited.Furthermore, counterfeit codes look the same as genuine products, printed in black on white paper, making it difficult to tell whether they are counterfeit or not.

[0008] In view of the above circumstances, an object of the present invention is to provide an optical structure capable of forming a code that is difficult to counterfeit and that is both highly readable and aesthetically pleasing. [Means for solving the problem]

[0009] A first aspect of the present invention is an optical structure comprising a translucent or transparent spacer layer laminated on a reflective layer that specularly reflects incident light, a printed layer having an image portion with a machine-readable code formed by light-colored level areas that are printed portions and non-light-colored level areas sandwiched between the light-colored level areas laminated on at least a portion of the spacer layer, and the spacer layer and the printed layer covered with a protective layer.

[0010] A second aspect of the present invention is an optical structure of the first aspect, in which a plurality of light level areas are formed in one of the silver background color of the product or the base color of a label covering the product, and a plurality of non-light level areas are formed in the other of the background color or the base color, and a machine-readable code is formed on the product by combining the plurality of light level areas and the plurality of non-light level areas.

[0011] A third aspect of the present invention is the optical structure of the first or second aspect, wherein the non-light level area is a black level area.

[0012] A fourth aspect of the present invention is the optical structure of the first or second aspect, wherein the dim level area is a white level area.

[0013] A fifth aspect of the present invention is the optical structure of the first aspect, wherein the reflective layer is a specular layer.

[0014] A sixth aspect of the present invention is the optical structure of the fifth aspect, wherein the specular layer is a vapor-deposited layer. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide an optical structure capable of forming a code that is difficult to counterfeit and that is both highly readable and aesthetically pleasing. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view for conceptually explaining the structure of an optical structure according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view for conceptually explaining the structure of an optical structure according to a second embodiment of the present invention. [Figure 3] FIG. 3 is a plan view for conceptually explaining an optical structure according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view illustrating one process in the manufacture of an optical structure according to a second embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view illustrating one process in the manufacture of an optical structure according to a second embodiment of the present invention. [Figure 6] FIG. 6 is a diagram for explaining the behavior of light incident on the optical structure. [Figure 7] FIG. 7 is a diagram for explaining the behavior of light incident on the optical structure. [Figure 8] FIG. 8 is a plan view showing an example of an optical structure according to a third embodiment of the present invention. [Figure 9] FIG. 9 is a schematic cross-sectional view for conceptually explaining the cross-sectional structure taken along line II in FIG. [Figure 10] FIG. 10 is a plan view showing an application example of the optical structure according to the fourth embodiment of the present invention. [Figure 11] FIG. 11 is a perspective view showing an application example of the optical structure according to the fifth embodiment of the present invention. [Figure 12]FIG. 12 is a top view showing an optical structure produced according to the first embodiment of the present invention. [Figure 13] FIG. 13 shows the results of scanning the barcode 52. As shown in FIG. [Figure 14] FIG. 14 shows the results of scanning the barcode 52. As shown in FIG. [Figure 15] FIG. 15 is a cross-sectional view for conceptually explaining the structure of an optical structure according to a modified example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The embodiments of the present invention are a group of embodiments based on a single, independent invention from the background. Furthermore, each aspect of the present invention is an aspect of the group of embodiments based on the single invention. Each configuration of the present invention may have each aspect of the present disclosure. Each feature of the present invention can be combined to 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 can have synergistic functions and exhibit synergistic effects.

[0018] [First embodiment] A first embodiment of the present invention will be described below with reference to FIG.

[0019] FIG. 1 is a diagram for conceptually explaining the structure of an optical structure 1 according to a first embodiment of the present invention.

[0020] That is, the optical structure 1 is formed by laminating a printed layer 30 as a scattering reflector having scattering reflectivity on a portion of a reflective layer 10 having regular reflectivity. The printed layer 30 includes a printed area and a non-printed area. The printed area includes a base print. In particular, it is preferable that the code printing area has a white level of the code formed by the base print.

[0021] The underprint is preferably printed with a white or light-colored opaque ink and can be the white level of the code and the printing of product images, patterns, logos, coats of arms, natural motifs, geometric patterns, emblems, coats of arms, or text, either alone or in combination.

[0022] The same ink can be used for the underprinting of the designs, patterns, logos, emblems, natural motifs, geometric patterns, emblems, coats of arms, or text, either alone or in combination, and for printing the white level of the code.The white level should preferably have an L* of 50 or more in the LAB color system under a 2-degree visual field when measured using the SCE method.

[0023] (direction definition) In this embodiment, the direction in which the printed layer 30 and the reflective layer 10 are stacked (i.e., the vertical direction in FIG. 1) is referred to as the stacking direction. Furthermore, the side of the reflective layer 10 on which the printed layer 30 is formed (the upper side of the paper in FIG. 1) is referred to as the upper side, and the opposite side (the lower side of the paper in FIG. 1) is referred to as the lower side. Furthermore, a view from the stacking direction is referred to as a planar view, and a view at a cross section along the stacking direction is referred to as a cross-sectional view.

[0024] The printing layer 30 may have an image portion formed thereon that is visible when viewed from the stacking direction. The image portion may be used to visually verify the authenticity of the optical structure 1. In other words, the image formed on the printing layer 30 may be authenticated.

[0025] The printed layer 30 has a diffuse reflectivity that reflects incident light isotropically on the reflective surface. A typical example of diffuse reflection is Lambertian reflection. The printed layer 30 may also have specular reflectivity. The printed layer 30 may also be made of a diffuse reflector. The printed layer 30 may be made of multiple layers, particularly two layers. When the printed layer 30 is made of two layers, the two layers may be in direct contact with each other or may be stacked with a resin interposed therebetween. As shown in FIG. 13, which will be described later, when two printed layers 30 are arranged on both the top and bottom surfaces of the reflective layer 10, different images can be formed on each of the two printed layers 30. This allows the optical structure 1 to have different images observed on the front and back when viewed from the stacking direction.

[0026] An identifier such as a barcode or two-dimensional code can be formed as an image on the printing layer 30. The image can be formed by a printed area and a non-printed area. The printing area can record multiple barcodes or two-dimensional codes as codes. Digital data can be recorded as codes. Examples of codes are barcodes and two-dimensional codes. An example of a two-dimensional code is QR Code (registered trademark). In a plan view, the identifier has a white level area on the printing layer 30, which is the printed portion, and a black level area sandwiched between the white level areas. The formed identifier can be authenticated using a barcode reader.

[0027] The image formed on the printing layer 30 can be perceived by the naked eye. This can improve the anti-counterfeiting and anti-falsification properties and aesthetics. The image described above may have multiple image portions. The image portion can display an image as a single image or as a combination of multiple images.

[0028] Images can be portraits, landmark motifs, art, nature motifs, geometric patterns, signs, symbols, emblems, coats of arms, or text, alone or in combination. Symbols and emblems can be motifs of flags, shields, swords, spears, crowns, stars, moons, hearts, logos, ribbons, lines, flowers, leaves, grains, fruits, birds, wings, fish, arthropods, mammals, reptiles, amphibians, mythical creatures, mythical gods, and mythical goddesses.

[0029] Landmarks can be heritage, ruins, historical buildings, mountains, valleys, rocks, monuments. Nature can be living things, stars, moon, sky, mountains, valleys, rocks. Living things can be flowers, leaves, grains, fruits, birds, wings, fish, arthropods, mammals, reptiles, amphibians. Mythical creatures can be unicorns, dragons, phoenixes. These motifs can represent symbols.

[0030] Symbols can represent countries, regions, states, groups, councils, treaties, alliances, unions, and axes.

[0031] In this specification, a first region can be formed in the printing layer 30 of the optical structure 1. 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 that verifies the authenticity of the optical structure 1 or a shape that identifies the optical structure 1.

[0032] In other words, the intended shape can be authenticated. Also, the intended shape can be identified. The intended shape can be large enough to be visible to the naked eye or to be visible under a microscope. The intended shape can be observed by illuminating the optical structure 1 from the observer's side.

[0033] The reflective layer 10 is a surface that anisotropically reflects incident light on the reflective surface. For example, it is a sheet on which a metal is vapor-deposited. The reflective layer 10 may also be made of a reflector.

[0034] The optical structure 1 may have a light-transmitting layer between each of the layers constituting the optical structure 1. The light-transmitting layer between each of the layers may be an adhesive layer that bonds the layers on both sides of that layer.

[0035] The main component of the reflective layer 10 can be an inorganic material, an organic material, or a mixture thereof. The inorganic material can be a metal, a metal compound, or silicon oxide (glass). Examples of metals are aluminum, silver, tin, chromium, nickel, copper, and gold.

[0036] Examples of metal compounds are titanium oxide, aluminum oxide, and zinc sulfide. Metal compounds generally have a high refractive index. The organic material can be a conductive polymer. Examples of conductive polymers can be polyacetylene and polyethylenedioxythiophene (PEDOT).

[0037] Furthermore, when printing a barcode on the printing layer 30 to create a black level area where reading by a barcode reader does not occur, it is desirable that the layer either reflects incident light anisotropically at the reflective surface, or has a retroreflectivity of incident light of 20% or less, or both.

[0038] The reflective layer 10 can be formed by deposition or printing. Physical deposition or chemical vapor deposition (CVD) can be used for deposition. Alternatively, aluminum foil can be used. The thickness of the aluminum foil can be 6 μm or more and 100 μm or less. For packaging materials, a thickness of 6 μm or more and less than 15 μm is preferred; for sealing materials, a thickness of 15 μm or more and less than 50 μm is preferred; and for trays, a thickness of 50 μm or more and 100 μm is preferred. Aluminum foil can be produced by thinning an aluminum plate by rolling. The surface of the aluminum foil may also be coated with a transparent resin. The transparent resin coated on the aluminum foil can be used as the spacer layer 20.

[0039] The glossiness of the reflective layer 10 measured at a 60° angle can be 40 or more. If the glossiness is high, it is easy to keep the retroreflectivity of incident light to 20% or less when reading the code with a reader. Even if the reflectivity is low, the code can be read with a reader, but the glossiness of the reflective layer 10 will be reduced.

[0040] The physical deposition may be performed by vacuum evaporation or sputtering. The reflective layer 10 of the physical deposition may be made of a metal. The target metal for the physical deposition may be any metal target with a purity of 4N or higher. The material of the reflective layer 10 of the physical deposition may be aluminum, silver, gold, or copper. The reflective layer of the physical deposition may be a single layer or a multilayer.

[0041] When forming the marking by printing, inks such as offset ink, silk screen ink, letterpress ink, and gravure ink can be used depending on the printing method.

[0042] The ink can be a resin ink, an oil-based ink, a water-based ink, etc. Also, depending on the drying method, it can be, for example, an oxidation polymerization type ink, an penetration drying type ink, an evaporation drying type ink, an ultraviolet curing type ink, etc.

[0043] The ink can be a pigment ink, a dye ink, or a mixture thereof. An example of a pigment ink is an inorganic pigment ink. The inorganic pigment ink can also be a magnetic ink. The magnetic ink can form a pattern due to its magnetism. This pattern is unique, which increases the difficulty of counterfeiting.

[0044] An example of dye ink is liquid crystal ink. An example of liquid crystal ink is cholesteric liquid crystal ink. Cholesteric liquid crystal reflects light of a specific wavelength. This results in a colored reflective layer. The reflectance also changes depending on the rotation direction of circularly polarized light and elliptically polarized light. Functional inks that change color depending on the illumination angle or observation angle may also be used as reflective layers.

[0045] Such functional inks include, for example, optical variable inks, color shifting inks, and pearl inks.

[0046] The scattering reflector of the print layer 30 scatters and reflects incident visible light. The scattering reflector can be primarily made of 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. Organic dyes such as azo dyes, anthraquinone dyes, indigo dyes, sulfide dyes, and carbonium dyes can also be mixed with the inorganic pigment.

[0047] Examples of metal oxides are titanium oxide, zinc oxide, and lead oxide.

[0048] Examples of metal compounds include barium sulfate, zinc sulfide, cadmium sulfide (cadmium yellow), zinc chromate, etc. Metal compounds generally have a high refractive index. Colored materials are materials that exhibit colors in the visible range, and include pigments, dyes, etc. Functional inks are functional inks that change color depending on the lighting angle or observation angle, and include optical variable inks, color shifting inks, pearl inks, etc.

[0049] The printing layer 30 can be formed by printing. Printing can be gravure printing or screen printing. Inkjet printing is also possible. Sublimation transfer printing or thermal transfer printing is also possible. This type of printing is particularly preferable as base printing. When printing on a curved surface, pad printing can be applied. Offset printing or flexographic printing is also possible.

[0050] The screen ruling for the screen printing of the undercoat printing can be, for example, 100 or more, 400, and preferably 200 to 350. The line speed can be, for example, 5 to 100 m / min. The gravure printing ruling can be, for example, 100 to 500. The line speed can be, for example, 50 to 500 m / min.

[0051] The ink viscosity can be, for example, 100 cp or more and 2000 cp or less. This viscosity can be measured with a kinematic viscometer. The solids ratio, which is the weight ratio of the ink including the solvent to the total amount of the ink medium and pigment, can be 10 to 30, or even 15 to 25. The pigment:medium ratio for the underprinting can be 1:3.75 to 1:6.25.

[0052] The thickness of the single printed layer 30 is preferably 700 nm or more and 500 μm or less.

[0053] The ink used to form the printed layer 30 by printing may be offset ink, silk screen printing, letterpress ink, intaglio ink, gravure ink, etc., depending on the printing method. The ink may be resin ink, oil-based ink, water-based ink, etc.

[0054] Depending on the drying method, the ink may be, for example, an oxidative polymerization type ink, a penetration drying type ink, an evaporation drying type ink, an ultraviolet curing type ink, etc. The ink may be a pigment ink, a dye ink, or a mixture thereof.

[0055] An example of pigment ink is magnetic ink, which can form a pattern due to its magnetism. This pattern is unique and therefore tends to increase the difficulty of counterfeiting.

[0056] Examples of dye inks are infrared luminescent inks, ultraviolet luminescent inks, and liquid crystal inks. An example of liquid crystal ink is cholesteric liquid crystal ink. Cholesteric liquid crystals reflect light of specific wavelengths, thus creating a colored reflective layer.

[0057] The reflectance changes depending on the rotation direction of circularly polarized light or elliptically polarized light. Functional inks that change color depending on the illumination angle or observation angle may also be used as the reflective layer. Examples of such functional inks include optically variable inks, color-shifting inks, and pearl inks.

[0058] The printed layer 30 forms an identifier that includes a machine-readable code, which may be a barcode that is readable by a barcode reader.

[0059] The thickness of the printing layer 30 that forms the barcode is preferably 1 μm or more and 500 μm or less. The area ratio of the printing area that acts as a scattering reflector in the printing layer 30 that forms the white level sections of the code is preferably 65% ​​to 100%. If this area ratio is 65%, reflection of incident light occurs more predominantly than transmission. The printing area of ​​the base printing can be a scattering reflector. The printing layer 30 can be a base printing layer. The base printing layer is usually a single layer.

[0060] The glossiness of the base print may be such that product images, patterns, logos, coats of arms, natural motifs, geometric patterns, emblems, coats of arms, or text may be printed on the base print in black, gray, or colored ink, either alone or in combination, and may be covered with a transparent varnish as the outermost layer to cover the print.

[0061] Furthermore, if the thickness of the printed layer 30 is 1 μm or more, the retroreflectivity of incident light can be 80% or less and 40% or more, thereby achieving a clear black and white contrast and enabling authentication.

[0062] When the printed layer 30 has two layers, the thickness is preferably 2 μm or more and 1 mm or less. The two printed layers 30 can be different printed matters or deposits. Furthermore, when the printed layer 30 has two layers, one layer can be a printed matter and the other layer can be a deposit.

[0063] The printing layer 30 may be partially removed by chemical etching, that is, the printing layer 30 may be partially formed.

[0064] The printing layer 30 may be partially removed by a laser.

[0065] Furthermore, when the printed layer 30 has two layers and is partially formed, the contours of the scattered reflection of the scattering reflectors of the two printed layers 30 may overlap. In this case, the printed layer 30 displays an image due to the contours of the two scattering reflection layers during transmitted observation.

[0066] By partially removing the printed layer 30, aesthetics can be improved. The intended contour of the partially formed printed layer 30 can be a security motif. The security motif can be an authentication motif or a verification motif.

[0067] The security motif can be a line drawing, a geometric pattern, text, or calligraphy. An example of a geometric pattern is a guilloche.

[0068] An example of text is microtext. Examples of calligraphy are Western calligraphy, Islamic calligraphy, Georgian calligraphy, Chinese calligraphy, Japanese calligraphy, Korean calligraphy, Filipino Suyat, Thai calligraphy, Indian Oriya, Nepalese calligraphy.

[0069] As described above, according to this embodiment, it is possible to provide an optical structure that is difficult to counterfeit and that is capable of forming a code that is both highly readable and aesthetically pleasing.

[0070] [Second embodiment] A second embodiment of the present invention will be described with reference to Figures 2 to 7. In the following description, components common to those already described will be assigned the same reference numerals and duplicated description will be omitted.

[0071] 2 is a cross-sectional view conceptually illustrating the structure of an optical structure 2 according to a second embodiment of the present invention. That is, the optical structure 2 is formed by laminating a reflective layer 10, an embossed layer 15, a spacer layer 20, a printed layer 30, and a protective layer 40 in this order.

[0072] The embossed layer 15 may form a relief structure. The surface having the relief structure can be called a relief surface.

[0073] Furthermore, an embossed layer 15 having a relief structure can be disposed between the spacer layer 20 and the printing layer 30 .

[0074] These relief structures are formed by the shape of a relief structure. The relief structure may be formed by transferring (embossing) a relief structure of a relief shape formed on the surface of a metal stamper onto a target object.

[0075] The relief structure has optical effects such as optical diffraction effect, anti-reflection effect, isotropic or anisotropic scattering effect, lens effect, polarization selective reflection effect, etc. This optical effect allows for visual verification of authenticity, i.e. the relief structure is visible.

[0076] In addition, it can be visually authenticated. The printing layer 30 on the relief surface having the relief structure is also visible and can be authenticated. In other words, the authenticity of the printing layer 30 on the relief surface having the relief structure can also be verified visually.

[0077] This provides an anti-counterfeiting and anti-falsification effect. In addition, this optical effect can also provide an aesthetic appearance. In other words, this optical effect allows the optical structure to have a visual effect.

[0078] The desired optical effect may be obtained by combining relief structures having one or more optical effects. The regions having each optical effect may be arranged in contact with, adjacent to, close to, at regular intervals, or alternately.

[0079] In this way, a relief surface having a relief structure with multiple optical effects can produce complex visual effects, which is effective in preventing counterfeiting and tampering. In addition, the aesthetic appearance of the optical structure 2 can be improved.

[0080] The relief structure has recesses and protrusions, and provides the optical structure 2 with optical properties such as diffraction, light reflection suppression, isotropic or anisotropic light scattering, refraction, polarization / wavelength selective reflection, transmission, and light reflection suppression.

[0081] The relief structure may have a diffraction grating structure with a pitch of 0.5 μm to 2 μm and a depth of 0.05 μm to 0.5 μm, for example. The relief structure imparts light-diffracting properties to the optical structure 2.

[0082] The relief structure may be a moth-eye structure or a deep grating structure with a pitch of 0.1 μm to 0.5 μm and a depth of 0.25 μm to 0.75 μm, for example. In this case, the relief structure imparts to the optical structure 2 the properties of light reflection suppression, polarization and wavelength selective reflection, transmission, and light reflection suppression.

[0083] The relief structure may have a non-periodic linear or dot-like repeating structure with an average pitch of 0.5 μm to 3 μm and a depth of 0.05 μm to 0.5 μm, for example. This relief structure provides the optical structure 2 with the property of emitting isotropically or anisotropically scattered light.

[0084] The relief structure may have regions with an average pitch of more than 3 μm and a depth of more than 0.5 μm, which allows for a refractive index different from that of adjacent layers, and the relief structure imparts refractive properties to the optical structure 2.

[0085] The relief structure may also include a relief surface (recording surface) disclosed in WO 2017 / 209113. That is, the relief surface in this embodiment can have a phase angle recorded area and a phase angle non-recorded area, like the recording surface disclosed in WO 2017 / 209113.

[0086] Furthermore, on the relief surface, areas other than the phase angle recording areas are phase angle non-recording areas, which are, in one example, mirror surfaces.

[0087] Next, the positional relationship of each component will be explained using an XYZ orthogonal coordinate system, where the relief surface is assumed to be arranged along the XY plane.

[0088] When light is incident from a direction that intersects with the relief surface, the incident light is modulated by the relief surface, resulting in a reconstructed image. The reconstructed image is an image of multiple reconstruction points. The reconstruction points are obtained at positions spaced apart from the relief surface in the Z direction. When the relief surface is viewed from a reconstruction point of interest, the range in the viewing angle direction in which the reconstructed image is reconstructed is called the viewing angle θ. In the following explanation, the viewing angle direction is the X direction or the Y direction.

[0089] On the relief surface, calculation element sections are defined according to the viewing angle θ from each reproduction point at which a reproduction image is reproduced. In this way, the calculation element sections are defined independently of the phase angle recording area and the phase angle non-recording area, and therefore usually overlap with the phase angle recording area and the phase angle non-recording area, respectively.

[0090] Furthermore, there are a plurality of regeneration points, and therefore there are the same number of computational element partitions as the number of regeneration points, corresponding to each of the plurality of regeneration points.

[0091] The reproduction point is disposed at a distance from the relief surface. The reproduction point is preferably reproduced at a distance of 5 mm or more and 25 mm or less from the relief surface in the Z direction. The reproduction point may be reproduced on the viewer's side of the relief surface or on the opposite side of the relief surface from the viewer. In either case, the distance of the reproduction point from the relief surface can be specified in the same way.

[0092] The viewing angle θ from the reproduction point is defined by the following equation (1).

[0093] θ<(A / m) (1) Here, when (λ / 2d)≦1, A=asin(λ / 2d), where λ is the wavelength of light, d is the arrangement interval of the unit blocks in the viewing angle direction, and m is a real number of 3 or more. Specifically, this wavelength λ of light can be 555 nm, which is the maximum relative luminosity factor of humans among visible light. The arrangement interval d can be the center-to-center distance between the unit blocks. The arrangement interval of the central unit blocks can be 10 nm or more and 200 nm or less.

[0094] The viewing angle θ is determined by the range in the X direction when the relief surface is viewed from the reproduction point of interest, and is 1 / 2 of the angle 2θ formed by the minimum value Xmin in the X direction and the maximum value Xmax in the X direction between the reproduction point of interest and the X direction. Note that the X and Y directions correspond to the X and Y coordinate axes of a Euclidean coordinate system, where the X direction is the direction in which the relief surface extends and the Y direction is the direction perpendicular to the X direction.

[0095] Note that the viewing angle θ is similarly defined when the viewing angle direction is the Y direction. That is, the viewing angle θ is determined by the range in the Y direction when the relief surface is viewed from a reproduction point of interest, and is ½ of the angle 2θ formed by the minimum value Ymin in the Y direction and the maximum value Ymax in the Y direction between the reproduction point of interest and the Y direction. Therefore, the arrangement interval d of the unit blocks corresponds to the arrangement interval dx of the unit blocks in the X direction when the viewing angle direction is the X direction, and corresponds to the arrangement interval dy of the unit blocks 12 in the Y direction when the viewing angle direction is the Y direction.

[0096] For this reason, the computational element partition is generally a square or a rectangle. However, the computational element partition may be a polygon other than a rectangle, or a circle or an ellipse. As for polygons, in addition to squares and rectangles, hexagons are also suitable. When the computational element partition is a shape other than a square or a rectangle, the minimum value (lower limit) of the X direction of the computational element partition is defined as Xmin, and the maximum value (upper limit) of the X direction of the computational element partition is defined as Xmax. Similarly, the minimum value of the Y direction of the computational element partition is defined as Ymin, and the maximum value of the Y direction of the computational element partition 16 is defined as Ymax.

[0097] When the shape of a unit block is square or rectangular, the corners of the square or rectangle are rounded, resulting in a rounded rectangle. Furthermore, a unit block may be fused with an adjacent unit block. In this case, even if the shape of each unit block is a rounded rectangle, the shape of the fused unit blocks will not be a rounded rectangle and will be deformed, but the optical effect will not change even if the shape is deformed by fusion.

[0098] The unit blocks are preferably arranged in an orderly fashion. The orderly arrangement may be an arrangement at intervals within a certain range or an arrangement at equal intervals. Typical orderly arrangements include a square arrangement and a hexagonal arrangement.

[0099] As can be seen from equation (1) above, 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 calculations using a computer, the calculation range can be limited to an upper limit of the viewing angle θ. In this way, limiting the calculation range shortens the calculation time.

[0100] Furthermore, even if calculations were performed for a range exceeding the viewing angle θ, the calculation would only involve calculation of diffraction that does not theoretically exist, and the results would only contribute as noise. However, in the above calculations, calculations for a range exceeding the viewing angle θ are not performed, so noise is not superimposed when the reconstructed image at the reconstruction point is reconstructed.

[0101] Both the phase angle recording area and the phase angle non-recording area include a plurality of unit blocks. For unit blocks included in an area of ​​the phase angle recording area that overlaps with a calculation element partition (overlapping area), a computer calculates a phase angle based on the phase component, and records the calculated phase angle in the corresponding unit block included in the overlapping area.

[0102] The relief surface of this embodiment is visible and can be authenticated. When the optical structure 2 having such a relief surface as a relief structure is tilted by more than a certain amount and observed from outside the range of the viewing angle θ, the reconstructed image disappears due to the relief structure.

[0103] On the other hand, if the visible image formed on the print layer 30 is a barcode, the barcode can be read by a barcode reader even under these observation conditions (outside the range of the viewing angle θ).

[0104] Furthermore, the reconstructed image described above can only be reconstructed with a point light source. Therefore, the reconstructed image disappears under diffuse lighting. However, the barcode can still be read by a barcode reader even under these observation conditions (outside the range of the viewing angle θ).

[0105] The viewing angle θ is preferably 5 degrees or more from the viewpoint of visibility of the reproduced image, and is preferably 15 degrees or less from the viewpoint of making the reproduced point easily disappear.

[0106] The optical properties of the optical structure 2 can be perceived visually, thereby improving the anti-counterfeiting and anti-tampering performance and aesthetic appearance. The relief structure described above may have a plurality of relief structure regions.

[0107] The relief structure area can display an image, either singly or in combination with other images, such as portraits, landmark motifs, art, natural motifs, geometric patterns, signs, symbols, emblems, coats of arms, or text.

[0108] Symbols and emblems can be motifs of flags, shields, swords, spears, crowns, stars, moons, hearts, logos, ribbons, lines, flowers, leaves, grains, fruits, birds, wings, fish, arthropods, mammals, reptiles, amphibians, mythical creatures, mythical gods and mythical goddesses.

[0109] Landmarks can be heritage sites, ruins, historical buildings, mountains, valleys, rocks, and monuments.

[0110] Nature can be living things, stars, moon, sky, mountains, valleys, and rocks. Living things can be flowers, leaves, grains, fruits, birds, wings, fish, arthropods, mammals, reptiles, and amphibians.

[0111] Mythical creatures can be unicorns, dragons, or phoenixes. These motifs can represent symbols. Symbols can represent countries, regions, states, groups, councils, treaties, alliances, unions, or axes.

[0112] 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.

[0113] The thermoplastic resin may be any one of acrylic resin, polyester resin, and polyamide resin, any one of copolymer resins, any one of composite resins, and any one of composite resins of copolymer resins.

[0114] The surface modifier may be a powder, wax, or oil. The powder may be a heat-resistant powder. The heat-resistant powder may be silica powder, polyethylene powder, fluorine-based powder, or silicone-based powder.

[0115] The wax may be paraffin wax, silicone, carnauba wax, and the oil may be silicone oil.

[0116] The embossed layer (not shown) has a relief structure on at least one surface thereof and is made of, for example, an ultraviolet curable resin, a thermoplastic resin, or a thermosetting resin.

[0117] The ultraviolet curable resin may be a curable resin, such as a monomer, oligomer, or polymer having an ethylenically unsaturated bond or an ethylenically unsaturated group.

[0118] 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.

[0119] The oligomer having an ethylenically unsaturated bond or an ethylenically unsaturated group may be an oligomer or cooligomer of epoxy acrylate, urethane acrylate, or polyester acrylate.

[0120] The polymer may be a polymer or copolymer of urethane-modified acrylic or epoxy-modified acrylic.

[0121] The ultraviolet curable resin may be any one of acrylic resin, acrylic acrylate resin, epoxy acrylate resin, urethane acrylate resin, polyester acrylate resin, and ethylene methacrylate resin, a copolymer resin of any one of these, a composite resin of any one of these, or a composite resin of any one of these copolymer resins.

[0122] The thickness of the embossed layer can be 1 μm or more and 25 μm or less.

[0123] When a thermoplastic resin is used as the material for the embossed layer, it can be any of an acrylic resin, an epoxy resin, a cellulose resin, a vinyl resin, any of a copolymer resin, any of a composite resin, or any of a composite resin of a copolymer resin.

[0124] The thermosetting resin of the embossed layer may be any one of urethane resin, melamine resin, epoxy resin, and phenol resin, a copolymer resin of any one of these, a composite resin of any one of these, and a composite resin of any one of these copolymer resins. The same material can be used for the protective layer 40.

[0125] The embossed layer may be colored. This can be achieved by adding a pigment or dye to the resin of the embossed layer. The pigment may be an inorganic pigment or an organic pigment. Alternatively, the pigment may be a fluorescent pigment, a pearlescent pigment, or a magnetic pigment. The dye may be a natural dye or a synthetic pigment. Alternatively, the dye may be a fluorescent dye.

[0126] The optical structure 2 may have a light-transmitting layer between each of the layers constituting the optical structure 2. The light-transmitting layer between each of the layers may be an adhesive layer that bonds the layers on both sides of that layer.

[0127] The spacer layer 20 has light-transmitting or transparency. The required light-transmitting or transparency of the spacer layer 20 may be at a level that allows light incident from the protective layer 40 side to reach the reflective layer 10 and allows light reflected by the reflective layer 10 to be transmitted. The spacer layer 20 may be colored. The spacer layer 20 may be a layer that transmits visible and infrared laser beams.

[0128] The spacer layer 20 may be configured to allow visible codes to be written onto it by laser, and may be made of a material such as polycarbonate or polyester that can withstand the heat of laser writing.

[0129] A material with some light scattering properties can also be used for the spacer layer 20. In this case, the transmittance in the visible region of wavelengths from 380 nm to 780 nm is 40% or more, preferably 60% or more. Typically, the transmittance at the laser beam wavelength of 1064 nm is preferably 30% or more.

[0130] Polyolefin and polymers having an aryl group can be used as materials for the spacer layer 20. Polyolefin and polymers having an aryl group are light-transmitting or transparent polymers.

[0131] The polymer containing aryl groups can be polycarbonate or polyester terephthalate. The polyolefin can be either polyethylene or polypropylene, or modifications thereof, or copolymers thereof.

[0132] Furthermore, polyolefins have a simple main chain structure and are thermally stable, so they undergo little chemical change when exposed to a laser beam with an energy level below a certain level, making it difficult for the spacer layer 20 to discolor even when irradiated with a laser beam with enough energy to remove the reflective layer 10.

[0133] Furthermore, since either polyethylene or polypropylene, or modified products thereof, or copolymers thereof are crystalline polymers, a certain amount of heat is required for phase transition when melted, and therefore there is little change when irradiated with a laser beam below a certain energy level.

[0134] Furthermore, aromatic hydrocarbons of aryl groups are resonant hybrids and therefore have excellent heat resistance, so deformation when irradiated with a laser beam with enough energy to remove the reflective layer 10 can be easily suppressed.

[0135] On the other hand, aromatic hydrocarbons have a high carbon content in their molecules and are easily carbonized, and when carbonized with sufficient heat, they can produce a sufficiently black color even in a thin layer. Therefore, when the spacer layer 20 is made of a polymer having an aryl group, if 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 produce a black color.

[0136] It is not necessary to remove the reflective layer 10 in the portion where the spacer layer 20 has been carbonized. By moving the focal point of the laser beam away from the reflective layer 10 (50 μm or more and 350 μm or less, depending on the irradiation energy and focal depth of the laser beam), 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.

[0137] The carbonized removed area is difficult to read with a barcode reader, but has excellent visibility, allowing a visible code to be recorded. The visible code can be a string of symbols, letters, numbers, or a combination of these.

[0138] This allows for both efficient processing using a barcode reader and visual confirmation of the code. The visible code in the carbonized removed area can also be recorded in the hologram portion to prevent tampering.

[0139] The visible code may contain part or all of the information of the code data recorded as a barcode. The visible code may also be stored in a table in a data server in correspondence with the barcode.

[0140] Alternatively, the data recorded in the barcode may be encrypted and recorded as a code. If part of the information in the code data recorded as a barcode is included, a hash can be used. This hash may be a cryptographic hash.

[0141] Hashing allows a barcode identifier to be linked to large amounts of data, even if the code is short. Encrypted codes can also be used to verify authenticity and keep data confidential.

[0142] An adhesive layer mainly composed of acrylic resin may be provided adjacent to the spacer layer 20. Although acrylic resin has low heat resistance, its thermal decomposition is depolymerization type, so as long as it has a certain molecular weight, its molecular structure remains after irradiation with a laser beam, and performance can be maintained. The molecular weight of the acrylic resin is preferably 100,000 or more.

[0143] Furthermore, as the molecular weight increases, the glass transition temperature also increases, so if the glass transition temperature is above a certain level, the molecular weight is generally high. Therefore, if the acrylic resin has a glass transition temperature of 40°C or higher, the molecular weight is sufficiently high that the adhesive will easily maintain its adhesion even when irradiated with a laser beam strong enough to remove the reflective layer. The thickness of the adhesive layer can be 0.1 μm or more and 10 μm or less.

[0144] The spacer layer 20 may be made of a polymer. If the spacer layer 20 is made of the same material as the scattering reflection layer, the two can be easily joined together by heat fusion.

[0145] The thickness of the spacer layer 20 is preferably in the range of 25 μm or more and 200 μm or less. 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, protrusions of the optical structure 1 are hardly noticeable when bonding or embedding, and flexibility of the spacer layer 20 is easily obtained.

[0146] The protective layer 40 has the same light-transmitting or transparent properties as the spacer layer 20, and protects the shape of the print layer 30 in plan view, thereby keeping the code machine-readable.

[0147] The protective layer 40 can be formed from various resins. The resin of the protective layer 40 can be polycarbonate resin or acrylic resin. The resin of the protective layer 40 can be thermoplastic resin or cured resin. If the protective layer 40 is formed from the same type of material as the spacer layer 20, all layers can be easily bonded together by heat fusion.

[0148] The difference in softening temperature between the protective layer 40 and the spacer layer 20 may be within 30° C. This makes it easy to bond the layers together by heat fusion. The thickness of the protective layer 40 is preferably 50 μm or more and 400 μm or less.

[0149] FIG. 3 is a plan view for conceptually explaining an optical structure according to a second embodiment of the present invention.

[0150] The plan view shown in FIG. 3 is an example of a plan view of the optical structure 2 as seen from the protective layer 40 side in the stacking direction.

[0151] In this example, the individual information record (image information record) 50 is formed by a visible code 51 formed by partially carbonizing the spacer layer 20, and a barcode 52 formed by the printing layer 30, in which the data of the visible code 51 is converted into a machine-readable code by combining the arrangement of printed white level areas RW and black level areas RB sandwiched between the white level areas RW.

[0152] The barcode 52 may include numbers or the like indicating an identification code below the multiple bars.

[0153] In this way, an identification code can be recorded in the individual information record 50. This optical structure 1 can be used as a security pass.

[0154] Furthermore, the printed layer 30 may have a brittle structure that breaks when peeled off, which makes it more difficult to tamper with the optical structure 2.

[0155] In Fig. 3, a visible code 51 and a barcode 52 are formed in the first region of the printed layer 30. In Fig. 3, the visible code 51 and the barcode 52 are formed, but only the barcode 52 may be formed.

[0156] The visible code 51 and the barcode 52 can be identification codes. The identification code of the barcode 52 can be a product code or a serial number.

[0157] In this case, the optical structure 1 can be a product tag, or a gift card.

[0158] In this case, the visible code 51 can be a claim code, and the identification code of the bar code 52 can be a serial number. This visible code may be a code recorded by carbonizing the spacer layer 20 with a laser beam.

[0159] The recorded individual information 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 gait pattern, a voiceprint, an iris, or a vein pattern.

[0160] Examples of personal data are name, country, country code, ID number. The optical structure 2 has an iridescent, white and metallic appearance in reflection. The face image has an iridescent, white and metallic appearance in reflection. The barcode 52 has an iridescent, white and metallic appearance in reflection.

[0161] The rainbow, white, and metallic appearances may be switched depending on the observation conditions. The optical structure 2 may have regions where rainbow colors appear, regions where interference colors appear, and regions where metallic luster appears.

[0162] (Method of manufacturing optical structure 2) Next, a method for manufacturing the optical structure 2 will be described with reference to FIGS.

[0163] 4 and 5 are diagrams for explaining one process in the manufacture of an optical structure according to the second embodiment of the present invention.

[0164] 4 shows a pre-structure 2A in which a printing layer 30 is laminated on a spacer layer 20. The printing layer 30 may be transferred using thermal transfer, a 3D printer, screen printing, inkjet printing, or gravure printing.

[0165] Fig. 5 shows an optical structure 2 formed by adhering a protective layer 40 that covers the printing layer 30 to the pre-structure 2A shown in Fig. 4. The protective layer 40 can be adhered by thermal compression bonding or by using an adhesive layer.

[0166] Next, the behavior of light irradiated onto the completed optical structure 2 from the protective layer 40 side will be described with reference to FIGS.

[0167] FIG. 6 is a diagram for explaining the behavior of light incident on the optical structure 2. As shown in FIG.

[0168] FIG. 7 is a diagram for explaining the behavior of light incident on the optical structure 2. As shown in FIG.

[0169] As shown in Figure 6, light L1 irradiated onto the printed layer 30 is scattered and reflected. As a result, a portion of the incident light, L1a, is retroreflected and returns to the direction of incidence. On the other hand, as shown in Figure 7, light L2 incident on a portion of the printed layer 30 where no scattering reflector is present passes through the spacer layer 20, reaches the reflective layer 10, and is specularly reflected. As a result, light L2 incident on a portion of the printed layer 30 where no scattering reflector is present is mainly reflected in a specular direction different from the direction of incidence.

[0170] Therefore, of the light emitted from the barcode reader, the light that strikes the reflective layer 10 is not received by the barcode reader, and part of the light that strikes the print layer 30 returns to the reader and is received.

[0171] This allows the reader to detect areas where the printed layer 30 is present as high signal level areas, and areas where the scattering reflector of the printed layer 30 is not present as low signal level areas.

[0172] This allows individual information records 50 to be formed by distinguishing the areas in the visible code 51 or barcode 52 (i.e., the first area) where the printing layer 30 exists in the areas corresponding to the white areas (areas that are recognized as white by the reader) and where the printing layer 30 does not exist in the areas corresponding to the black areas (areas that are recognized as black by the reader).

[0173] The individual information record 50 can be visible in diffuse reflection, and the individual information record 50 can be machine readable in diffuse reflection.

[0174] The width of each of the white level area RW and the black level area RB in a direction intersecting the longitudinal direction (depth direction in FIGS. 7 and 8) may correspond to the information recorded in the barcode 52.

[0175] The standard size of the width of one module, which is the recording unit of a barcode bar, is specified as 0.33 mm. In the JAN standard barcode, the width of one module is 0.15 to 2.1 times the standard size, while in JIS X0507, the recommended width is 0.8 to 2.0 times.

[0176] Therefore, the width of one module, which is the recording unit of the barcode 52, is preferably in the range of 33 μm to 700 μm. In other words, the minimum width of the bars 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.

[0177] Furthermore, the maximum length of the barcode 52 (maximum length in the longitudinal direction of the white level area RW and black level area RB) is mainly limited by the barcode reader, and if it is 10 cm or less, it can be read by a standard barcode reader.

[0178] In order to reduce reading errors, the maximum length of the barcode 52 is preferably 6 mm or less.

[0179] The first area also has a plurality of white level areas RW and a plurality of black level areas RB sandwiched between two adjacent white level areas RW in the X direction. The alternating white level areas RW and black level areas RB can form a barcode 52 that encodes data such as the owner of the visible code 51. A product identification code can also be recorded in the barcode.

[0180] As described above, in the optical structure 2 of this embodiment, the individual information records 50 can be formed by controlling the printing width of the printing layer 30. The individual information records 50 are covered with the protective layer 40, making it difficult to rearrange the material of the printing layer 30. In other words, it is difficult to tamper with the individual information records 50 recorded on the printing layer 30.

[0181] As a result, it is highly difficult to counterfeit the individual information record 50 of the optical structure 2. Therefore, the optical structure 2 on which the individual information record 50 is formed has high security, unlike a code printed on paper.

[0182] Furthermore, the formed individual information record 50 has a rainbow color, white color, and metallic luster, and is aesthetically pleasing. Furthermore, the individual information record 50 can be used as 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 on which the individual information record 50 is formed can resolve the tradeoff between aesthetics and readability.

[0183] A product identification code can be recorded in the barcode as an identifier including a readable code. The product identification code can be a JAN code, EAN code, or UPC code. A QR code can also be formed as a two-dimensional code, and a URL can be recorded in the QR code as an identifier including a readable code.

[0184] As described above, according to this embodiment, an optical structure can be provided that can form a code that is both highly readable by a reader and aesthetically pleasing. Furthermore, by using special processing and materials for the reflective layer 10 and printing, an optical structure can be provided that is difficult to counterfeit. [Third Embodiment] A third embodiment of the present invention will be described with reference to Figures 8 and 9. In the following description, components common to those already described will be assigned the same reference numerals and redundant description will be omitted.

[0185] FIG. 8 is a plan view showing an example of an optical structure according to a third embodiment of the present invention.

[0186] 8 shows a plan view of a card 101 as an example of an optical structure according to this embodiment. The card 101 has a first area 102 in which the individual information record 50 is formed by printing, and a second area 103 in which text and a facial image are written with a laser beam.

[0187] The first area 102 has an identifier formed therein that includes a machine-readable code (for example, a barcode 52 that can be read by a barcode reader).

[0188] The text and facial image in the second area 103 are visible. The text and facial image in the second area 103 can be an identifier. The text and facial image in the second area 103 can be personal information. The text and facial image in the second area 103 can be card owner information.

[0189] The card 101 can also be applied to a page of a booklet. Examples of booklets are passport booklets and visa booklets.

[0190] FIG. 9 is a schematic cross-sectional view for conceptually explaining the cross-sectional structure taken along line II in FIG.

[0191] 9, card 101 has a spacer layer 105 on top of a white core layer 106 in place of spacer layer 20. The material of spacer layer 105 is a polymer having an aryl group, and a visible code can be written on it by irradiating it with a laser beam.

[0192] 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 so that a visible code can be written by a laser. The thickness of the spacer layer 105 is preferably 50 μm or more and 400 μm or less.

[0193] In the first region 102 of the card 101 shown in Fig. 8, a transfer foil 200 having a printed layer 30 is disposed between the spacer layer 105 and the protective layer 40, as shown on the right side of Fig. 9. 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 printed layer 30 is not present.

[0194] As shown in Figure 9, the transfer foil 200 comprises a peeling layer 201, a printing layer 30 formed under the peeling layer 201, an embossed layer 202 formed under the printing layer 30, a reflective layer 10 formed under the embossed layer 202, and an adhesive layer 203 bonded under the reflective layer 10 and on top of the spacer layer 105.

[0195] The adhesive layer 203 adheres to the reflective layer 10 on its upper surface and to the spacer layer 105 on its lower surface.

[0196] An anchor layer (not shown) may be provided at any location between the printing layer 30 and the adhesive layer 203. Furthermore, a mask layer (not shown) may be provided at any location between the anchor layer and the printing layer 30.

[0197] The embossed 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 embossed layer 202 is the same as the relief structure described in the first embodiment.

[0198] As mentioned above, the adhesive layer 203 of the transfer foil 200 can be attached to the spacer layer 105, in which case the embossed layer 202 is arranged between the protective layer 40 and the printing layer 30 in the stacking direction, and the peel layer 201 can serve as the protective layer 40.

[0199] Alternatively, the adhesive layer 203 of the transfer foil 200 may be attached to the protective layer 40. In this case, the embossed layer 202 is disposed between the spacer layer 105 and the printing layer 30 in the stacking direction.

[0200] With the above-described configuration, the transfer foil 200 exhibits a predetermined optical effect such as a hologram or a diffraction grating.

[0201] (Card 101 manufacturing method) Next, a method for manufacturing the card 101 will be described.

[0202] To manufacture the card 101, first, the transfer foil 200 is prepared.

[0203] The transfer foil 200 is formed by laminating a release layer 201, a print layer 30, an embossed layer 202, a reflective layer 10, and an adhesive layer 203 in this order on a plastic film (not shown).

[0204] Next, the card 101 is formed. When forming the card 101, the plastic film and transfer foil 200 are placed on a card base material having a white core layer 106 and a spacer layer 105, with the adhesive layer 203 facing the card base material.

[0205] When heat and pressure are applied to the transfer foil 200 from above the plastic film and then the plastic film is peeled off, the transfer foil 200 is bonded to the card base material.

[0206] The card base material and transfer foil 200 are then covered with a plastic film that will become the protective layer 40, and laminated using heat and pressure to produce a card 101 having a first area 102 and a second area 103, as illustrated in Figure 8.

[0207] The release layer 201 may be colored. Coloring can be achieved by adding a pigment or dye to the resin of the release layer 201. The pigment may be an inorganic pigment, an organic pigment, or a mixture of inorganic and organic pigments. The pigment may be a fluorescent pigment, a pearl pigment, or a magnetic pigment, either alone, in a homogeneous blend, a heterogeneous blend, or a homogeneous blend of heterogeneous pigments.

[0208] The dyes can be natural dyes, synthetic dyes, or a mixture of natural and synthetic dyes. The dyes can also be fluorescent dyes.

[0209] The release layer 201 can be formed on a plastic film by printing or coating, using gravure coating, microgravure coating, or die coating.

[0210] Printing can be gravure printing or screen printing. The thickness of the plastic film can be 10 μm or more and 50 μm or less from the viewpoint of processability. The thickness of the release layer 201 is preferably 0.5 μm or more and 5 μm or less.

[0211] The release layer 201 can accept the printing layer 30. The release layer 201 may be mainly composed of acrylic resin. Acrylic resin easily accepts the printing layer 30. A printed body with an OVD section optically variable device having a release layer 201 that can accept the printing layer 30 can be printed as a single unit.

[0212] Immediately after manufacture, card 101 has no information written in second area 103. By irradiating second area 103 with a laser beam, spacer layer 105 is carbonized to form laser marks 105a, and information (laser marks) 105a can be written.

[0213] The information written as the laser mark may be personal data, a biometric identifier, a code, etc. An example of a biometric identifier is a facial image.

[0214] Similar to the printed layer 30 of the first embodiment, a white level region RW and a black level region RB can be formed in the printed layer 30 of the first region 102 of the card 101. As a result, the card 101 of this embodiment achieves the same effects as the optical structure 1 of the first embodiment.

[0215] Furthermore, by combining the individual information record 50 written in the first area 102 with the information written in the second area 103, and further with the optical effect produced by the transfer foil 200, security can be further improved.

[0216] Furthermore, in card 101, print layer 30 on which individual information record 50 is formed is covered with protective layer 40, making it difficult to tamper with.

[0217] It should be noted that the first region 102 in this embodiment is not limited to a configuration including the transfer foil 200. For example, if the optical effect of the embossed layer 202 is not to be imparted to the first region 102, the printed layer 30 may be formed only in the portion to be the first region 102, and the identifier may be formed in the same procedure as in the first embodiment.

[0218] As described above, according to this embodiment, it is possible to provide an optical structure and a manufacturing method thereof that are capable of forming a code that is difficult to counterfeit and that is both highly readable and aesthetically pleasing.

[0219] [Fourth embodiment] A fourth embodiment of the present invention will be described with reference to Fig. 10. In the following description, components common to those already described will be assigned the same reference numerals and redundant description will be omitted.

[0220] FIG. 10 is a plan view showing an application example of the optical structure according to the fourth embodiment of the present invention.

[0221] As shown in Figures 10(a) and 10(b), the optical structure 400 of this embodiment has a reflective layer 401 with specular reflectivity and a plurality of printed light level areas 402 arranged on at least a portion 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 level areas 402.

[0222] Figures 10(a) and 10(b) show an example of an 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 a reflective layer 401, and Figure 10(c) shows the corresponding prior art.

[0223] When the surface of a product is used as the reflective layer 401, the surface of the product has a glossiness similar to that of a mirror layer, for example. Products whose surfaces can be used as the reflective layer 401 include, but are not limited to, cards made of metallized paper, book covers, packaging labels, etc.

[0224] Even if a barcode 404 is placed on the glossy reflective layer 401, the barcode formed in black cannot be read.

[0225] For this reason, in the prior art, as shown in Fig. 10(c), a sticker 415 with a black barcode 414 printed thereon is attached to the product 420. However, this creates a sense of incongruity in terms of appearance and design, and there is a risk that the brand image of the product 420 will be damaged.

[0226] However, it is possible to read a barcode 404 formed in white or a light color. Therefore, in the optical structure according to this embodiment, the barcode 404 is formed by combining light-colored level areas 402.

[0227] The color of the light level area 402 forming the barcode 404 is preferably white, as shown in Fig. 10(a). Alternatively, it can be pink, as shown in Fig. 10(b). By forming the barcode 404 in a light color such as white or pink, the code information of the barcode 404 can be read even from a glossy surface.

[0228] 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 base print 406 of the product design.

[0229] As can be seen from FIGS. 10(a) and 10(b), such a barcode 404 appears to be integrated with the product design, there is no unnaturalness due to the printing of the barcode 404, and the brand image of the product is not damaged.

[0230] As described above, according to this embodiment, an optical structure and a manufacturing method thereof can be provided that form a barcode in a white or light color that is preferably used on products so that the barcode can be read even when placed on a glossy surface and does not create an unnatural appearance or design.

[0231] [Fifth embodiment] A fifth embodiment of the present invention will now be described.

[0232] For example, during the Christmas sales season, alcoholic beverages such as champagne are sold in packages made of glossy silver metallized paper. As explained in the fourth embodiment, even if a black barcode is printed on the glossy metallized paper, the information in the barcode cannot be read.

[0233] Therefore, conventionally, as explained in the fourth embodiment with reference to FIG. 10(c), a sticker 415 on which an ink-colored, ie, black barcode 414 is printed is attached to the package.

[0234] However, the work of attaching the stickers 415 is usually done manually, which increases the workload, and since it is done manually, there is a risk that the stickers will be attached unevenly, which will result in an unattractive appearance.

[0235] Furthermore, for example, in the case of Christmas products, which are primarily colored white, green, and red, if a sticker 415 with a black barcode 414 printed on it is affixed to the package, the impression of the Christmas product will be significantly diminished.

[0236] Furthermore, since the work of attaching the sticker 415 is a separate process from the printing process, there is a risk that a large amount of rework will be required if the sticker 415 is forgotten to be attached during the manufacturing of the product.

[0237] The optical structure according to this embodiment can solve such problems.

[0238] An optical structure according to a fifth embodiment of the present invention will be described with reference to Fig. 11. In the following description, components common to those already described will be assigned the same reference numerals and redundant description will be omitted.

[0239] FIG. 11 is a perspective view showing an application example of the optical structure according to the fifth embodiment of the present invention.

[0240] The optical structure 500 shown in FIG. 11 is an example realized using a package for alcoholic beverages such as champagne.

[0241] The optical structure 500 has a machine-readable code, such as a barcode 503, formed using the background color of the product 501 that is the package and the background color of the label 502 that covers the product 501.

[0242] The barcode 503 is formed by a combination of a plurality of light level areas 504 formed in one of the background color of the product 501 or the background color of the label 502 and a plurality of non-light level areas 505 formed in the other of the background color of the product 501 or the background color of the label 502.

[0243] 11, product 501 is a silver package that is placed over a bottle of alcoholic beverages such as champagne. Label 502 is made of a light-blocking barrier film laminated onto product 501 and has a white background.

[0244] The barcode 503 is formed without white printing, with the silver background color as the non-light level area 505 and the label background as the light level area 504, without using black ink.

[0245] In this way, the barcode 503 is formed on the product 501 using the background color of the product 501 that is the package and the background color of the label 502 that covers the product 501 .

[0246] This barcode 503 is machine-readable even if the product 501 is glossy, so there is no need to affix a black ink-colored sticker 415 with a black barcode 414 printed on it to the product 501.

[0247] In this way, it is possible to ensure that the product 501 is provided with a machine-readable barcode 503 without ruining the Christmas atmosphere.

[0248] According to the optical structure 500 of this embodiment, the following effects can be achieved.

[0249] As described above, according to this embodiment, it is possible to provide an optical structure capable of forming a code that can be read even from a glossy surface, and a method for manufacturing the same.

[0250] 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.

[0251] [Example 1] Example 1 corresponds to the first embodiment, and the optical structure 1 has a reflective layer 10 and a printed layer 30 as shown in FIG.

[0252] The materials of the reflective layer 10 and the printed layer 30 in the optical structure 1 of Example 1 are as follows.

[0253] 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).

[0254] (Fabrication of Optical Structure 1) FIG. 12 is a top view showing an optical structure produced according to the first embodiment of the present invention.

[0255] To produce the optical structure 1, a white inorganic pigment (titanium oxide) that would become the printed layer 30 was transferred to the reflective layer 10 by screen printing to a thickness of 50 μm, and then dried to form a scattering reflective layer.As a result, the optical structure 1 of Example 1 having the printed layer 30 on the reflective layer 10 was produced, as shown in Figure 12.

[0256] In the optical structure 1 shown in FIG. 12, the barcode 52 printed on the print layer 30 as shown in region K was scanned with a reader.

[0257] 13 and 14 are diagrams showing the results of scanning a barcode 52. The viewing angles from the reader are different between Fig. 13 and Fig. 14. Fig. 13 shows the results of scanning the barcode 52 with the reader from an oblique angle, while Fig. 14 shows the results of scanning the barcode 52 with the reader from almost the front.

[0258] From the reading results shown in FIGS. 13 and 14, it was found that information can be obtained by reading barcode 52 with the reader tilted at an angle of 20° to 80° from the normal to the surface of the structure.

[0259] [Example 2] In Example 2, the material for the printing layer 30 was a white ink containing titanium oxide pigment (weight ratio 1:25, TiO2:SSS WAC varnish (acrylic resin) = 1g:25g weight parts (TiO2 is 3% in the ink)), and an optical structure 1 with the same configuration as Example 1 was produced.

[0260] When a code was formed on the printing layer 30 made of such white ink by metal deposition, the QR code was readable, although slightly less readable, and the barcode was readable without any problems. It is likely that the barcode would be readable even if the metal deposition was transparent.

[0261] Considering that the solid content ratio of SSS WAC varnish is 15 to 25%, the readable range of solid content ratio is considered to be TiO2:medium=1 g:3.75 to 6.25 g.

[0262] Although the best mode for carrying out the present invention has been described above with reference to the accompanying drawings, the scope of the present disclosure is not limited to the illustrated and described embodiments, but can also include all embodiments that have equivalent effects to the object of the present invention. Furthermore, the scope of the present disclosure is not limited to the features of the invention defined by the claims, but also includes all disclosed individual features and any combination of those features.

[0263] For example, as shown in the cross-sectional view of Figure 15, two optical structures according to any embodiment can be bonded together with their respective reflective layers 10 facing each other to form an optical structure 301 having individual information recordings 50A and 50B on both sides.

[0264] In particular, although FIG. 15 shows an example in which optical structures 1A and 1B having the same structure are bonded together, the structures of the optical structures to be bonded together may be different.

[0265] Furthermore, the identifier is not limited to the above-mentioned barcode 52, but may be, for example, a two-dimensional code.

[0266] The terms "part," "element," "pixel," "cell," "segment," "unit," "display," and "article" used in this disclosure refer to a physical entity. A physical entity can refer to a material form or a spatial form surrounded by a material. A physical entity can be a structure. A structure can have a specific function. A combination of structures with specific functions can produce a synergistic effect due to the combination of the functions of each structure.

[0267] Additionally, terms used in this disclosure and particularly in the appended claims (e.g., the body of the appended claims) are generally intended as "open" terms (e.g., the term "having" should be interpreted as "having at least," the term "including" should be interpreted as "including but not limited to," etc.).

[0268] Furthermore, when interpreting terms, configurations, features, aspects, and embodiments, reference should be made to drawings as necessary. Matters that can be directly and unambiguously derived from drawings should be the basis for amendment, equivalent to the text.

[0269] Furthermore, where a particular number of introduced claim recitations is intended, such intent will be expressly recited in the claim; absent such recitation, such intent does not exist. For example, to aid in understanding, the following appended claims may include the use of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed as meaning limited to embodiments including only one such recitation.

[0270] The introductory phrases "one or more" or "at least one" should be construed to mean "one" or "one or more." The same applies to the use of express articles used to introduce claim recitations. [Explanation of symbols]

[0271] 1, 2 Optical structure 2A, 2B Optical structure (pre-structure) 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 Cards 102 First area 103 Second area 105 Spacer layer 106 White core layer 200 transfer foil 201 Peeling layer 202 Embossed layer 203 Adhesive layer 301 Optical structure 400 Optical Structure 401 Reflective layer 402 Light level area 404 Barcode 406 Undercoat printing 414 Barcode 415 Seal 420 items 500 Optical Structure 501 products 502 Label 503 Barcode 504 Light Level Area

Claims

1. a spacer layer having light-transmitting or transparency is laminated on a reflective layer that specularly reflects incident light; a printing layer having an image portion with a machine-readable code formed by light-colored level areas that are printed portions and non-light-colored level areas sandwiched between the light-colored level areas is laminated on at least a part of the spacer layer; an optical structure, wherein the spacer layer and the printing layer are covered with a protective layer;

2. forming a plurality of said light level areas in one of the silver background color of the product or the background color of a label covering said product; forming a plurality of non-light level areas in the other of the background color or the base color; 2. The optical structure of claim 1, wherein a combination of a plurality of said dimmed level areas and a plurality of said non-dimmed level areas forms said machine-readable code on said product.

3. The optical structure according to claim 1 or 2, wherein the non-light level area is a black level area.

4. The optical structure according to claim 1 or 2, wherein the dim level area is a white level area.

5. The optical structure of claim 1 , wherein the reflective layer is a specular layer.

6. The optical structure of claim 5 , wherein the specular layer is a vapor-deposited layer.

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