# US 8,770,487 B2 · Information recording medium and method of reading information from information recording medium, and image detection apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,487 B2 - Document ID: US8770487B2 - Status: Granted - Kind: B2 - Application number: 12/005,338 - Filed: 2007-12-27 - Published: 2008-10-16 - Granted: 2014-07-08 - Earliest claimed: 2006-04-27 - Assignees: Toppan Printing Co., Ltd. - Applicants: Toshiki Toda; Harumi Oota; Masami Inokuchi; Yasushi Kishimoto; Fang Chi Su - Inventors: Toshiki Toda; Harumi Oota; Masami Inokuchi; Yasushi Kishimoto; Fang Chi Su - Web page: https://patentgrep.com/patent/US8770487B2 ## CPC - B44F 1/10: Changing, amusing, or secret pictures - B42D 25/328: Diffraction gratings; Holograms - G02B 5/1814: {structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings (G02B5/189 takes precedence)} - G02B 5/1819: {Plural gratings positioned on the same surface, e.g. array of gratings (plural diffractive elements positioned sequentially along the optical path G02B27/4272)} - G03H 1/0244: {Surface relief holograms (replicating hologram without interference recording G03H1/0276)} - G06K 19/06037: {multi-dimensional coding} - B42D 25/29: Securities; Bank notes - G03H 2001/0497: {Dot matrix holograms} - G06K 2019/0629: {Holographic, diffractive or retroreflective recording} - B44F: SPECIAL DESIGNS OR PICTURES - 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 - G03H: HOLOGRAPHIC PROCESSES OR APPARATUS (holograms, e.g. point holograms, used as ordinary optical elements G02B5/32; producing stereoscopic or other three-dimensional effects G02B30/00; diffraction-grating systems G02B27/44; systems using moiré fringes G02B27/60; optical logic elements G02F3/00; stereo-photography G03B35/00; photosensitive materials or processes for photographic purposes G03C; {stereo-photographic or similar processes G03C9/00}; apparatus for processing exposed photographic materials G03D; analogue computers performing mathematical operations with the aid of optical elements G06E3/00; authentication by radiation, of concealed information carried by holograms or diffraction gratings G06K19/16; holographic storage G11B7/0065, G11C13/04; {stereoscopic or other three dimensional effects in television systems H04N13/00}) - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS ## Abstract In an information recording medium according to the present invention, in which an information recording medium has diffraction grating cells arranged therein, a plurality of types of the diffraction grating cells make up one information recording area. At least one type of the diffraction grating cells included in the diffraction grating cells making up the information recording area are information recording elements, while the other types of the diffraction grating cells included in the diffraction grating cells making up the information recording area are information hiding elements. The information is recorded by two-dimensional arrangement of the diffraction grating cells constituting the information recording elements in the information recording area. ## Claims ### Claim 1 An information recording medium, comprising: an arrangement of diffraction grating cells constituting cells each formed of a diffraction grating, wherein the information recording medium is formed of a paper base material and has an uneven surface and the diffraction grating cells are arranged on the uneven surface of the information recording medium, a plurality of types of the diffraction grating cells make up one information recording area, two or more types of the diffraction grating cells included in the diffraction grating cells making up the information recording area are information recording elements, two or more types of the diffraction grating cells included in the diffraction grating cells making up the information recording area are information hiding elements, at least one of the diffraction grating cells included in the diffraction grating cells making up the information recording area is dummy, the diffraction grating cells of different types included in the diffraction grating cells making up the information recording area are configured of diffraction gratings having different grating angles from each other, information is recorded in a two-dimensional arrangement of the diffraction grating cells constituting the information recording elements in the information recording area, when the diffraction grating cells are irradiated with an illumination light from a light source, only one diffraction grating light ray is emitted from one diffraction grating cell, and the illumination light is a diffused illumination light that irradiates the diffraction grating cell in a plurality of angles and the diffraction light ray diffracts and diverges in a certain degree. ### Claim 2 (depends on 1) The information recording medium according to claim 1, wherein the grating angle between the diffraction grating cells of different types included in the diffraction grating cells making up the information recording area has a predetermined difference or a difference an integer multiple of the predetermined difference. ### Claim 3 (depends on 1) The information recording medium according to claim 1, wherein the diffraction grating cells of different types included in the diffraction grating cells making up the information recording area are configured of diffraction gratings having the same grating pitch. ### Claim 4 (depends on 1) The information recording medium according to claim 1, wherein the diffraction grating cells of at least two different types included in the diffraction grating cells making up the information recording area are configured of diffraction gratings having different grating pitches. ### Claim 5 (depends on 1) The information recording medium according to claim 1, wherein the information recording elements and the information hiding elements included in the diffraction grating cells making up the information recording area are configured of diffraction gratings having different grating pitches. ### Claim 6 (depends on 1) The information recording medium according to claim 1, wherein a plurality of the information recording areas are arranged, and the types of the diffraction grating cells arranged as the information recording elements fail to coincide with each other in at least two information recording areas included in the information recording areas. ### Claim 7 (depends on 6) The information recording medium according to claim 6, wherein the diffraction grating cells arranged as information recording elements in one of said plurality of information recording areas are arranged as information hiding elements in another one of the information recording areas. ### Claim 8 (depends on 1) The information recording medium according to claim 1, wherein a plurality of diffraction grating cells included in at least one of the information recording elements and the information hiding elements are arranged in the areas other than the information recording area. ### Claim 9 (depends on 1) The information recording medium according to claim 1, wherein at least any one of a character, a pattern and an image is displayed with the diffraction grating cells as pixels. ### Claim 10 A system for authenticating hidden information comprising: an information recording medium on which the hidden information is recorded, the information recording medium being formed of a paper base material and including a first layer and a transparent second layer stacked on the first layer and including a light reflection layer, the second layer having an uneven surface, wherein a plurality of minuscule diffraction grating elements each having a diffraction grating holding the whole or part of hidden information, and a plurality of miniscule diffraction grating elements each having a diffraction grating holding dummy information irrelevant to the hidden information, are arranged on the surface of the second layer, a grating pitch and a grating angle are set in such a manner that the whole or part of light rays diffracted by the diffraction grating elements based on the illumination light from a light source enter a predetermined spatial area, and in the case where the whole or part of the diffraction light rays from a diffraction grating element group including a combination of at least two diffraction grating elements among the plurality of miniscule diffraction grating elements each having a diffraction grating holding the whole or part of hidden information enter the predetermined area, and a sum of reproduction information in the predetermined area is developed as predetermined one or plurality of hidden information, and a predetermined color and a predetermined pattern are arranged on the first layer in accordance with arrangement of the diffraction grating elements holding the hidden information; and an authentication apparatus, the authentication apparatus including: a light source which radiates illumination light rays of a color in the same color group as or complementary to a predetermined color of a pattern arranged on a first layer corresponding to diffraction grating elements holding the hidden information and on the first layer corresponding to diffraction grating elements around the diffraction grating elements holding the hidden information; reading means for reading the hidden information developed by a combination of the light rays diffracted, through the diffraction grating elements, from the illumination light rays radiated on the diffraction grating elements from the light source; and authentication means for authenticating the hidden information based on the information read by the reading means. ### Claim 11 A system for authenticating hidden information comprising: an information recording medium on which the hidden information is recorded, the information recording medium being formed of a paper base material and including a first layer and a transparent second layer stacked on the first layer and including a light reflection layer, the second layer having an uneven surface, wherein a plurality of minuscule diffraction grating elements each having a diffraction grating holding the whole or part of hidden information, and a plurality of miniscule diffraction grating elements each having a diffraction grating holding dummy information irrelevant to the hidden information, are arranged on the surface of the second layer, a grating pitch and a grating angle are set in such a manner that the whole or part of light rays diffracted by the diffraction grating elements based on the illumination light from a light source enter a predetermined spatial area, and in the case where the whole or part of the diffraction light rays from a diffraction grating element group including a combination of at least two diffraction grating elements among the plurality of miniscule diffraction grating elements each having a diffraction grating holding the whole or part of hidden information enter the predetermined area, and a sum of reproduction information in the predetermined area is developed as predetermined one or plurality of hidden information, and a predetermined color and a predetermined pattern are arranged on the first layer in accordance with arrangement of the diffraction grating elements holding the hidden information, wherein a pattern having a color corresponding to a wavelength of light radiated at the time of reading the hidden information is arranged on the first layer corresponding to the diffraction grating elements around the diffraction grating elements holding the hidden information; and an authentication apparatus, the authentication apparatus including: a light source which radiates illumination light rays of a color in the same color group as or complementary to a predetermined color of a pattern arranged on a first layer corresponding to diffraction grating elements holding the hidden information and on the first layer corresponding to diffraction grating elements around the diffraction grating elements holding the hidden information; reading means for reading the hidden information developed by a combination of the light rays diffracted, through the diffraction grating elements, from the illumination light rays radiated on the diffraction grating elements from the light source; and authentication means for authenticating the hidden information based on the information read by the reading means. ### Claim 12 A system for authenticating hidden information comprising: an information recording medium on which the hidden information is recorded, the information recording medium being formed of a paper base material and including a first layer and a transparent second layer stacked on the first layer and including a light reflection layer, the second layer having an uneven surface, wherein a plurality of minuscule diffraction grating elements each having a diffraction grating holding the whole or part of hidden information, and a plurality of miniscule diffraction grating elements each having a diffraction grating holding dummy information irrelevant to the hidden information, are arranged on the surface of the second layer, a grating pitch and a grating angle are set in such a manner that the whole or part of light rays diffracted by the diffraction grating elements based on the illumination light from a light source enter a predetermined spatial area, and in the case where the whole or part of the diffraction light rays from a diffraction grating element group including a combination of at least two diffraction grating elements among the plurality of miniscule diffraction grating elements each having a diffraction grating holding the whole or part of hidden information enter the predetermined area, and a sum of reproduction information in the predetermined area is developed as predetermined one or plurality of hidden information, and a predetermined color and a predetermined pattern are arranged on the first layer in accordance with arrangement of the diffraction grating elements holding the hidden information, wherein a pattern having a color complimentary to the color corresponding to a wavelength of light radiated at the time of reading the hidden information is arranged on the first layer corresponding to the diffraction grating elements around the diffraction grating elements holding the hidden information; and an authentication apparatus, the authentication apparatus including: a light source which radiates illumination light rays of a color in the same color group as or complementary to a predetermined color of a pattern arranged on a first layer corresponding to diffraction grating elements holding the hidden information and on the first layer corresponding to diffraction grating elements around the diffraction grating elements holding the hidden information; reading means for reading the hidden information developed by a combination of the light rays diffracted, through the diffraction grating elements, from the illumination light rays radiated on the diffraction grating elements from the light source; and authentication means for authenticating the hidden information based on the information read by the reading means. ### Claim 13 (depends on 10, 11, 12) The system according to one of claims 10 to 12, wherein a function of selecting wavelength is added to the reading means. ### Claim 14 An information recording medium, comprising: an arrangement of diffraction grating cells constituting cells each formed of a single diffraction grating, wherein the information recording medium is formed of a paper base material and has an uneven surface and the diffraction grating cells are arranged on the uneven surface of the information recording medium, a plurality of types of the diffraction grating cells make up one information recording area, two or more different types of the diffraction grating cells included in the diffraction grating cells making up the information recording area are information recording elements, two or more different types of the diffraction grating cells included in the diffraction grating cells making up the information recording area are information hiding elements, at least one of the diffraction grating cells included in the diffraction grating cells making up the information recording area is dummy, the diffraction grating cells of different types included in the diffraction grating cells making up the information recording area are configured of diffraction gratings having different grating angles from each other and having different grating angles from each of the two or more different types of the diffraction grating cells that are the information hiding elements, information is recorded in a two-dimensional arrangement of the diffraction grating cells constituting the information recording elements in the information recording area, when the diffraction grating cells are irradiated with an illumination light from a light source, only one diffraction grating light ray is emitted from one diffraction grating cell, and the illumination light is a diffused illumination light that irradiates the diffraction grating cell in a plurality of angles and the diffraction light ray diffracts and diverges in a certain degree.