# US 11,305,575 B2 · Counterfeit-preventive optical element and information medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,305,575 B2 - Document ID: US11305575B2 - Status: Granted - Kind: B2 - Application number: 16/089,333 - Filed: 2017-03-30 - Published: 2019-11-28 - Granted: 2022-04-19 - Earliest claimed: 2016-03-30 - Assignees: Toppan Printing Co., Ltd. - Applicants: Toppan Printing Co., Ltd. - Inventors: Kazuhiro Yashiki - Web page: https://patentgrep.com/patent/US11305575B2 ## CPC - B42D 25/324: Reliefs - B42D 25/328: Diffraction gratings; Holograms - B42D 25/342: Moiré effects - G02B 3/08: with discontinuous faces, e.g. Fresnel lens {(diffractive Fresnel lenses G02B5/1876)} - G02B 5/045: {Prism arrays} - B42D 25/351: Translucent or partly translucent parts, e.g. windows - B42D 25/364: Liquid crystals - B42D 25/369: Magnetised or magnetisable materials - B42D 25/378: Special inks - G02B 5/18: Diffraction gratings {(holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44)} - B42D: BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract Provided are a highly versatile counterfeit-preventive optical element applicable to both the banknote field and the ID field and an information medium including the optical element. A counterfeit-preventive optical element (1) of an embodiment includes a first layer (2), second layer (3), and a third layer (6) that are stacked in this order. A relief structure (R) is provided between the first layer (2) and the second layer (3), the first layer (2) includes a first region (4) and a second region (5), the first region (4) totally reflects incident light incident from the first layer (2) due to at least one of the angle of a face of the relief structure (R) and the refractive index ratio of the first layer (2) and the second layer (3), and the second region (5) transmits or refracts at least some of incident light incident from the first layer (2) due to one of the angle of a face of the relief structure (R) and the refractive index ratio of the first layer (2) and the second layer (3). The transparency of the second region (5) is higher than the transparency of the first region (4) only when the optical element is observed from the first layer (2) at a particular angle. ## Claims ### Claim 1 A counterfeit-preventive optical element, comprising a first layer; a second layer comprising a refractive index different from a refractive index of the first layer; and a third layer partly welded or joined to the first layer, the first layer, the second layer, and the third layer being stacked in this order, wherein a relief structure is provided between the first layer and the second layer, the first layer at least includes a first region and a second region, an inclination angle of a slope of the relief structure in the first region differs from an inclination angle of a slope of the relief structure in the second region, the first region is configured to totally reflect incident light incident from the first layer at a particular angle due to at least one of the angles of the relief structure and a refractive index ratio of the first layer and the second layer, the second region is configured to transmit or refract at least some of incident light incident from the first layer at the particular angle due to one of the angles of the relief structure and a refractive index ratio of the first layer and the second layer, and a transparency in the second region is higher than a transparency in the first region only when the optical element is observed from the first layer at the particular angle, and wherein at least a part of the first region and at least a part of the second region produce a parallax image. ### Claim 2 (depends on 1) The counterfeit-preventive optical element according to claim 1, wherein at least a part of the second layer is a gas or a liquid encapsulated between the first layer and the third layer. ### Claim 3 (depends on 1) The counterfeit-preventive optical element according to claim 1, wherein the refractive index of the first layer is higher than the refractive index of the second layer, the relief structure comprises a slope inclined to a surface of the first layer, and when the counterfeit-preventive optical element is observed from any observation point, incidence angle Θf1, incidence angle Θf2, refractive index N1, refractive index N2, refractive index N3, and refractive index N4 satisfy expressions: Θf1≥arcsin(N2/N1) arcsin(N4/N3)>Θf2 where Θf1 is an incidence angle of light incident on the slope of the relief structure in the first region, Θf2 is an incidence angle of light incident on the slope of the relief structure in the second region, N1 is a refractive index of the first layer in the first region, N2 is a refractive index of the second layer in the first region, N3 is a refractive index of the first layer in the second region, and N4 is a refractive index of the second layer in the second region. ### Claim 4 (depends on 1) The counterfeit-preventive optical element according to claim 1, wherein the third layer is provided in contact with the second layer and is a print layer displaying a symbol, an image, or both. ### Claim 5 (depends on 1) The counterfeit-preventive optical element according to claim 1, further comprising a color layer provided in contact with the second layer. ### Claim 6 (depends on 5) The counterfeit-preventive optical element according to claim 5, further comprising an electromagnetic wave absorbing layer provided in contact with an opposite face of the color layer to the second layer. ### Claim 7 (depends on 1) The counterfeit-preventive optical element according to claim 1, further comprising a color layer provided in contact with the first layer, and an electromagnetic wave absorbing layer provided in contact with the second layer. ### Claim 8 (depends on 1) A counterfeit-preventive optical element comprising two or more of the counterfeit-preventive optical elements according to claim 1. ### Claim 9 (depends on 1, 8) The counterfeit-preventive optical element according to claim 8, wherein at least one of the optical elements according to claim 1 is stacked on at least one other of the optical elements according to claim 1 and at least two layers of the stacked counterfeit-preventive optical elements comprise a periodic relief structure, and the periodic relief structures produce moire. ### Claim 10 (depends on 1) The counterfeit-preventive optical element according to claim 1, wherein at least a part of the relief structure comprises a periodic structure, and an added layer capable of producing moire together with the periodic structure is included. ### Claim 11 (depends on 1) An information medium comprising the counterfeit-preventive optical element according to claim 1. ### Claim 12 (depends on 2) The counterfeit-preventive optical element according to claim 2, wherein the refractive index of the first layer is higher than the refractive index of the second layer, the relief structure comprises a slope inclined to a surface of the first layer, and when the counterfeit-preventive optical element is observed from any observation point, incidence angle Θf1, incidence angle Θf2, refractive index N1, refractive index N2, refractive index N3, and refractive index N4 satisfy expressions: Θf1≥arcsin(N2/N1) arcsin(N4/N3)>Θf2 where Θf1 is an incidence angle of light incident on the slope of the relief structure in the first region, Θf2 is an incidence angle of light incident on the slope of the relief structure in the second region, N1 is a refractive index of the first layer in the first region, N2 is a refractive index of the second layer in the first region, N3 is a refractive index of the first layer in the second region, and N4 is a refractive index of the second layer in the second region. ### Claim 13 (depends on 2) The counterfeit-preventive optical element according to claim 2, wherein the third layer is provided in contact with the second layer and is a print layer displaying a symbol, an image, or both. ### Claim 14 (depends on 3) The counterfeit-preventive optical element according to claim 3, wherein the third layer is provided in contact with the second layer and is a print layer displaying a symbol, an image, or both. ### Claim 15 (depends on 2) The counterfeit-preventive optical element according to claim 2, further comprising a color layer provided in contact with the second layer. ### Claim 16 (depends on 3) The counterfeit-preventive optical element according to claim 3, further comprising a color layer provided in contact with the second layer. ### Claim 17 (depends on 4) The counterfeit-preventive optical element according to claim 4, further comprising a color layer provided in contact with the second layer. ### Claim 18 (depends on 2) The counterfeit-preventive optical element according to claim 2, further comprising a color layer provided in contact with the first layer, and an electromagnetic wave absorbing layer provided in contact with the second layer. ### Claim 19 (depends on 3) The counterfeit-preventive optical element according to claim 3, further comprising a color layer provided in contact with the first layer, and an electromagnetic wave absorbing layer provided in contact with the second layer.