Laminate, booklet, and method of using the laminate

Abstract

The present invention addresses the problem of providing a laminate, etc., capable of being used as, inter alia, an information medium for which security is improved by adding an information display that is recognizable via an infrared camera or the like while maintaining the black-colored, etc., information display of a laser coloring layer.　Provided is a laminate characterized by comprising: a base material layer; a near infrared ray-absorbing layer that is formed on a first surface side of the base material layer and includes a near infrared ray-absorbing ink composition containing a near infrared ray-absorbing material; and a laser coloring layer that is formed on a second surface side of the base material layer, contains a laser coloring agent, and performs coloring by applying laser light, wherein the near-infrared ray absorbing material includes cesium tungsten oxide or lanthanum hexaboride, and applying laser light to a target portion of the near-infrared ray absorbing layer lowers near-infrared ray absorption in at least a prescribed wavelength range in the target portion.

Description

Technical Field

[0001] The present invention relates to a laminate including a near-infrared absorption layer capable of printing or drawing (marking) characters, images, etc. that can be recognized by a near-infrared camera or the like, a booklet including such a laminate as a sheet, and a method of using the laminate.

Background Art

[0002] In recent years, regarding data pages, ID (identification) cards such as identity certificates, cards such as credit cards and cash cards, banknotes, etc., improving security has become an issue, and various proposals have been made for preventing forgery.

[0003] In Patent Document 1, a marking method has been proposed in which an infrared-absorbing pattern is formed by applying energy such as laser light to a base material containing ytterbium oxide. However, the infrared absorbency of ytterbium oxide is not sufficiently high, and there are also problems in terms of ease of handling.

[0004] In addition, techniques such as anti-counterfeiting using infrared absorption materials have been proposed as in Patent Documents 2 to 7, but problems remain in any of the techniques. For example, in Patent Document 2, variable information is printed by a printing method, and the following demerits exist: · When printing or transferring to the card surface, it is easily tampered with, resulting in low security. Wear resistance and other resistance also deteriorate. · When printing or transferring to the middle layer of the card, after printing (or issuing) personal information, press processing, card size finishing processing, etc. will be performed, so on-site issuance is considered difficult. Furthermore, if any problem occurs in the processing step, since the personal information is different for each, it will be necessary to start over from the first printing.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent No. 4323578 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-505444 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-246821 [Patent Document 4] Japanese Patent Application Laid-Open No. 2008-162233 [Patent Document 5] Japanese Patent No. 6443597 [Patent Document 6] Japanese Patent No. 6507096 [Patent Document 7] Japanese Patent No. 6541400 [Patent Document 8] Japanese Patent No. 6160830 [Patent Document 9] Japanese Patent No. 5854329 [Patent Document 10] International Publication No. 2018 / 151238 [Patent Document 11] Japanese Patent No. 6167803 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] In view of the above, the present invention provides a laminate that can be used for security information media such as ID cards and data pages, etc., and can be used as an information medium with improved security by adding an information display recognizable by an infrared camera or the like while maintaining the information display by color development such as black color development of the laser color development layer, a booklet body using such a laminate, and a related method. [Means for Solving the Problems]

[0007] In order to solve the above problems, the present invention provides a laminate including a base material layer, a near-infrared absorption layer including a near-infrared absorbing ink composition containing a near-infrared absorbing material formed on the first surface side of the base material layer, and a laser coloring layer including a laser coloring agent formed on the second surface side of the base material layer and coloring when irradiated with laser light. The near-infrared absorbing material includes cesium tungsten oxide or lanthanum hexaboride, and by irradiating the target portion of the near-infrared absorption layer with laser light, the near-infrared absorption property of the target portion in at least a predetermined wavelength range is reduced.

[0008] The laminate may further include a first surface side printing layer containing a near-infrared transmissive colored ink composition or a fluorescent ink composition formed on the first surface side of the base material layer.

[0009] The laminate may further include a first surface side hologram layer having near-infrared transmissivity formed on the first surface side of the base material layer.

[0010] The laminate may further include a second surface side printing layer containing a colored ink composition or a fluorescent ink composition formed on the second surface side of the base material layer so as to overlap the laser coloring layer.

[0011] The laminate may further include a second surface side hologram layer formed on the second surface side of the base material layer so as to overlap the laser coloring layer.

[0012] The laminate may further include a first surface side transmissive layer having visible light transmissivity and near-infrared transmissivity, which is formed on the first surface side of the base material layer and is the outermost layer on the first surface side of the laminate.

[0013] The laminate may further include a second surface side transmissive layer having visible light transmissivity and near-infrared transmissivity, which is formed on the second surface side of the base material layer and is the outermost layer on the second surface side of the laminate.

[0014] A plurality of convex optical element portions may be formed in an area at least partially overlapping the near-infrared absorption layer on the surface of the first surface side transmissive layer opposite to the near-infrared absorption layer.

[0015] In some regions on the surface of the second-side transmissive layer opposite to the laser color-forming layer, a plurality of convex optical element portions may be formed.

[0016] The laminate may further include a window portion that penetrates the base material layer and the laser color-forming layer and is formed so as to overlap at least a part of the near-infrared absorbing layer, and has visible light transmissivity and near-infrared transmissivity.

[0017] The laminate may further include a base material intermediate layer. The base material intermediate layer may include a first portion and a second portion. The base material layer may include a first base material layer and a second base material layer. The first portion of the base material intermediate layer may be located between the first base material layer and the second base material layer. The second portion of the base material intermediate layer may be located at an end of the base material intermediate layer and may not be located between the first base material layer and the second base material layer.

[0018] The near-infrared absorbing layer may include a near-infrared information display portion that displays information by a change in near-infrared absorption characteristics in the near-infrared absorbing layer caused by applying laser light. The laser color-forming layer may include a visible information display portion that displays information by a change in visible light absorption characteristics in the laser color-forming layer caused by applying laser light. The information displayed by the near-infrared information display portion and the information displayed by the visible information display portion may include the same information.

[0019] The present invention also provides a booklet formed by folding a plurality of sheets, wherein at least one of the plurality of sheets is the laminate provided by the present invention, and the laminate may be folded together with other sheets at the second portion of the base material intermediate layer.

[0020] The present invention also provides a laminate including a substrate layer, a near-infrared absorption layer including a near-infrared absorbing ink composition containing a near-infrared absorbing material formed on the first surface side of the substrate layer, a laser coloring layer including a laser coloring agent formed on the first surface side of the substrate layer and coloring upon irradiation with laser light, and a window portion having visible light transmittance and near-infrared transmittance formed to penetrate the substrate layer and the laser coloring layer and at least partially overlap the near-infrared absorption layer. The near-infrared absorbing material contains cesium tungsten oxide or lanthanum hexaboride. By irradiating a target portion of the near-infrared absorption layer with laser light, the near-infrared absorbability of the target portion in at least a predetermined wavelength range is reduced. A laminate is provided.

[0021] The near-infrared absorption layer may include a near-infrared information display portion that displays information by a change in near-infrared absorption characteristics in the near-infrared absorption layer generated by irradiating with laser light. The laser coloring layer may include a visible information display portion that displays information by a change in visible light absorption characteristics in the laser coloring layer generated by irradiating with laser light. The information displayed by the near-infrared information display portion and the information displayed by the visible information display portion may include the same information.

[0022] The present invention also provides a method for reducing the near-infrared absorbability of a target portion of a near-infrared absorption layer in a laminate including a near-infrared absorption layer including a near-infrared absorbing ink composition containing a near-infrared absorbing material formed on the first surface side of a substrate layer, the near-infrared absorbing material containing cesium tungsten oxide or lanthanum hexaboride, and a laser coloring layer including a laser coloring agent formed on the second surface side of the substrate layer and coloring upon irradiation with laser light, by irradiating the target portion of the near-infrared absorption layer with laser light so as to reduce the near-infrared absorbability of the target portion in at least a predetermined wavelength range.

[0023] The present invention also provides a method for authenticating a laminate, which includes: a near-infrared absorption layer including a base material layer and a near-infrared absorption ink composition containing a near-infrared absorbing material formed on the first surface side of the base material layer, wherein the near-infrared absorbing material contains cesium tungsten oxide or lanthanum hexaboride, and the near-infrared absorption layer includes a near-infrared information display portion that displays information by a change in near-infrared absorption characteristics in the near-infrared absorption layer; a laser color-developing layer including a laser color-developing agent formed on the second surface side of the base material layer, which develops color when irradiated with laser light, and the laser color-developing layer includes a visible information display portion that displays information by a change in visible light absorption characteristics in the laser color-developing layer; and comparing the display content of the near-infrared information display portion with the display content of the visible information display portion to authenticate the laminate.

[0024] The present invention also provides a method for authenticating a laminate, which includes: a near-infrared absorption layer including a base material layer and a near-infrared absorption ink composition containing a near-infrared absorbing material formed on the first surface side of the base material layer, wherein the near-infrared absorbing material contains cesium tungsten oxide or lanthanum hexaboride, and the near-infrared absorption layer includes a near-infrared information display portion that displays information by a change in near-infrared absorption characteristics in the near-infrared absorption layer; a laser color-developing layer including a laser color-developing agent formed on the first surface side of the base material layer, which develops color when irradiated with laser light, and the laser color-developing layer includes a visible information display portion that displays information by a change in visible light absorption characteristics in the laser color-developing layer; a window portion having visible light transmissivity and near-infrared light transmissivity, which penetrates through the base material layer and the laser color-developing layer and is formed to at least partially overlap with the near-infrared absorption layer; and comparing the display content of the near-infrared information display portion with the display content of the visible information display portion to authenticate the laminate.

Advantages of the Invention

[0025] According to the present invention, by providing the near-infrared absorption layer and the laser coloring layer on surfaces that are opposite to each other when viewed from the base material layer, or on surfaces that are on the same side but do not completely overlap, it becomes possible to realize, in the same laminate, personal information printing in the laser coloring layer such as black coloring, and personal information printing in the near-infrared absorption layer that is difficult to visually recognize under visible light but can be recognized using an infrared camera or the like. In particular, by providing the near-infrared absorption layer on the surface opposite to the laser coloring layer when viewed from the base material layer, it is possible to avoid the near-infrared absorption characteristics of the near-infrared absorption layer being affected by laser printing on the laser coloring layer.

Brief Description of the Drawings

[0026]

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[0027] Hereinafter, a laminate, a booklet, and a method of using the laminate, which are exemplary embodiments of the present invention, will be described with reference to the drawings. However, note that the laminate, the booklet, and the method of using the laminate according to the present invention are not limited to the specific embodiments described below, and can be appropriately changed within the scope of the present invention. Individual functions, elements, etc. included in the embodiments described later can be appropriately deleted or changed within the scope of the present invention, and it is also possible to add any functions, elements, etc. not included in the embodiments within the scope of the present invention, and it is also possible to implement each embodiment in an appropriate combination. For example, in the following embodiments, a laminate in which a colored ink layer visible to the naked eye is printed on a base material or a transparent sheet will be described. However, instead of the colored ink layer, or in addition to the colored ink layer, a fluorescent ink layer can be formed by printing using a fluorescent ink composition that emits light when irradiated with excitation light, or a hologram layer can be formed, or it may be possible not to form a colored ink layer or the like on the base material or the transparent sheet. It is not essential to form the near-infrared absorption layer (near-infrared absorbing ink layer) by offset printing, and it can also be formed by silk screen printing, gravure printing, flexographic printing, inkjet printing, etc. (it is not necessary to be microdisplay printing). The colored ink layer, the fluorescent ink layer, the hologram layer, etc. preferably have near-infrared transmissivity that transmits at least a part of the irradiated near-infrared rays, but it is not essential for them to have near-infrared transmissivity. Also, in the following embodiments, a laminate in which an oversheet layer (transparent sheet) is formed on the uppermost layer and the lowermost layer of the laminate will be described, but it is not essential to provide these oversheet layers. It is not essential to form the near-infrared absorbing ink layer by printing, and the near-infrared absorbing ink layer and the colored ink layer or the like may be formed by the same method or different methods. In the examples described later, it is shown that it is effective to use near-infrared (ray) laser light as the laser light, and in each embodiment, the laser light will be described as being near-infrared laser light. However, the laser light that can be used in the present invention is not limited to this.That is, it is not essential to use near-infrared laser light as the laser light (e.g., Nd:YAG laser, YVO4 laser, fiber laser, etc.), and it is also possible to use laser light from an ultraviolet laser (e.g., THG laser, etc.), a visible light laser (e.g., SHG laser, etc.), a far-infrared laser (e.g., CO2 laser), etc.

[0028] In the following embodiments, "near-infrared" is defined as an electromagnetic wave having a wavelength of 780 nm to 2000 nm (from "JIS Z 8117:2002 Terms for Far-Infrared"). "Near-infrared laser light (near-infrared laser beam)" is defined as laser light having a wavelength within the above near-infrared wavelength range. Also, "visible light" is defined as an electromagnetic wave having a wavelength of 400 nm to 780 nm. Further, in the following embodiments, "near-infrared absorbency" means the property of absorbing at least a part of the irradiated near-infrared light, and "near-infrared transparency" means the property of transmitting at least a part of the irradiated near-infrared light. Similarly, in the following embodiments, "visible light absorbency" means the property of absorbing at least a part of the irradiated visible light, and "visible light transparency" means the property of transmitting at least a part of the irradiated visible light. Also, in the following embodiments, "laser marking" on a near-infrared absorption layer by laser light such as near-infrared laser light means irradiating the near-infrared absorption layer with laser light to change the absorption characteristics of the near-infrared absorption layer with respect to near-infrared light, thereby drawing (or writing) some display content such as a pattern, characters, or other information on the near-infrared absorption layer. Furthermore, in the following embodiments, "laser marking" on a laser color-developing layer by laser light such as near-infrared laser light means irradiating the laser color-developing layer with laser light to change the absorption characteristics of the laser color-developing layer with respect to visible light and near-infrared light, thereby drawing (or writing) some display content such as a pattern, characters, or other information on the laser color-developing layer.

[0029] (First Embodiment) FIG. 1 is a view showing an observation image (visible light image) of the front surface of the laminate in the first embodiment of the present invention by visible light (the outermost surface on the side of the oversheet layer 14 in FIG. 5; the same applies to other figures). In the present embodiment and each subsequent embodiment, the laminate 1 is assumed to be a printed matter for identifying an individual such as an identity card, but is not limited thereto, and the laminate 1 can be produced as any laminate such as cards such as credit cards and cash cards, banknotes, etc. On the base material layer 9 of the laminate 1 (see FIG. 5 and the like described later), the laser coloring layer 10 is fused by heat pressing, and a person image 2 and person identification information 3 are drawn by laser marking in which near-infrared laser light is irradiated onto the laser coloring layer 10. The person image 2 is drawn by irradiating near-infrared laser light so as to draw a person by laser marking on the laser coloring layer 10. The person identification information 3 is drawn by irradiating near-infrared laser light so as to write the identification information (name, personal identification number, etc.) of the person by laser marking on the laser coloring layer 10. Further, as shown in FIG. 5 described later, on the oversheet layer 14, a mark 4 is printed using a near-infrared light-transmissive colored ink (visible light-absorbing colored ink) such as UV SOYBI SG yellow (manufactured by DIC Graphics), UV SOYBI SG red (manufactured by DIC Graphics), UV SOYBI SG blue (manufactured by DIC Graphics), UV 161 yellow S (manufactured by T&K TOKA), UV 161 red S (manufactured by T&K TOKA), UV 161 blue S (manufactured by T&K TOKA) (colored ink layer 11 in FIG. 5).

[0030] FIG. 2 is a view showing an observation image (near-infrared image) of the front surface of the laminate in the first embodiment of the present invention by a near-infrared camera (note that the outer shape of the laminate is drawn for the purpose of easy viewing. The same applies to other figures). Such an observation image can be obtained by observing using a near-infrared camera or the like. The person image 2 and the person identification information 3 drawn by laser marking on the laser color development layer 10 have absorbability with respect to visible light and near-infrared light, and thus can be recognized not only by visible light but also by a near-infrared camera. On the other hand, since the mark 4 is formed by printing using a near-infrared transmissive colored ink, it cannot be recognized (or at least is difficult to recognize) by a near-infrared camera.

[0031] FIG. 3 is a view showing an observation image (visible light image) of the back surface of the laminate in the first embodiment of the present invention under visible light (the surface that can be seen by turning the laminate 1 around the AX axis in FIG. 1. In FIG. 5, it is the outermost surface on the side of the oversheet layer 15. The same applies to other embodiments). A mark 5 is printed on the back surface of the base material layer 9 using a near-infrared transmissive colored ink (visible light absorbing colored ink) (colored ink layer 12 in FIG. 5).

[0032] FIG. 4 is a diagram showing an observation image (near-infrared image) of the back surface of the laminate in the first embodiment of the present invention by a near-infrared camera (note that the outer shape of the laminate is drawn for ease of viewing the figure. The same applies to other figures). In the observation image, the printed image 6 is formed by printing on the base material layer 9 or on the over-sheet layer 15 (see FIG. 5) using a near-infrared absorbing ink containing at least one of cesium tungsten oxide and lanthanum hexaboride, which is a near-infrared absorbing material (near-infrared absorbing ink layer 13). As will be described later with reference to the experimental results, a near-infrared absorbing ink composition containing cesium tungsten oxide or lanthanum hexaboride has the property that the absorption rate for near-infrared rays in at least a predetermined wavelength range decreases (the reflectivity increases) when irradiated with near-infrared laser light. By irradiating near-infrared laser light onto the near-infrared absorbing ink layer formed by printing using such a near-infrared absorbing ink composition so as to draw characters, images (pictures, figures, etc.), etc. (laser marking), the near-infrared absorption characteristics of the drawn portion change, and thus characters, images, etc. recognizable using an infrared camera or the like are formed on the near-infrared absorbing ink layer. The human image 7 is drawn by irradiating near-infrared laser light so as to draw a human on the printed image 6 by laser marking. The person identification information 8 is drawn by irradiating near-infrared laser light so as to write in the identification information (name, personal identification number, etc.) of the person on the printed image 6 by laser marking.

[0033] The portrait 2 drawn by laser marking on the laser color - developing layer 10 and the portrait 7 drawn by laser marking on the near - infrared absorbing ink layer 13 may be of the "same" pattern (information), and the personal identification information 3 drawn by laser marking on the laser color - developing layer 10 and the personal identification information 8 drawn by laser marking on the near - infrared absorbing ink layer 13 may be of the "same" pattern (information). For example, when using the laminate 1 for some kind of identity card such as a passport, by performing laser marking in such a manner, the security function can be enhanced. For example, when a passport is being checked by a staff member such as an immigration officer at an airport, etc., it can be checked with an infrared camera. However, if a "portrait photo (black - and - white or color laser - marked image of a person)" is provided by laser marking on the laser - printed part of the laser color - developing layer 10, and a "portrait photo (laser - marked image)" of the same pattern as that on the laser color - developing layer 10 is provided on the pattern of the laser - marked part of the near - infrared absorbing ink layer 13, although it cannot be confirmed only under visible light, when using an infrared camera in addition to a visible - light camera or the naked eye, etc., the fact that the same pattern exists in the laser color - developing layer 10 and the near - infrared absorbing ink layer 13 can be recognized by the staff members performing inspection work, etc. That is, even if a forger forges the photo on the laser color - developing layer 10 (even if a portrait of a person is drawn on the laser color - developing layer 10 by laser marking), if it can be confirmed using an infrared camera, etc., that there is a different portrait photo (portrait of a person drawn by laser marking on the near - infrared absorbing ink layer 13) in a part that is not visible under visible light, the staff members, etc. can immediately recognize that the laminate 1 as an identity card, etc. is a forged one. Similarly, not only for the laminate 1 of the first embodiment, but also in all embodiments (including all variations of each embodiment), the "same" pattern can be provided on the laser color - developing layer and the near - infrared absorbing ink layer, and forgery can be immediately detected in the same way.

[0034] As the cesium - tungsten - oxide - containing ink composition, the chemical formula (general formula) is Cs x W y O zInks containing cesium tungsten oxide represented by [x, y, z are each a positive real number] can be used. In one example, Cs having a hexagonal crystal structure described in Patent Document 8 (Japanese Patent No. 6160830) 0.33 Inks containing fine particles represented by WO3 can be used. As a method for qualitatively analyzing cesium tungsten oxide, for example, the content of cesium tungsten oxide (Cs 0.33 WO3) can be confirmed by the following method. (1) Absorption photometry: Whether the wavelength in the infrared region is absorbed (2) Energy Dispersive X-ray Spectroscopy: Whether W or Cs is present (3) Electron Probe Micro Analyzer (EPMA): Whether W is present (4) X-ray Absorption Fine Structure (XAFS): Valence of W As the lanthanum hexaboride-containing ink composition, an ink containing fine particles represented by the chemical formula LaB6 can be used. The near-infrared absorbing ink contains a dispersant, a monomer, synthetic resins, auxiliaries, etc. in addition to cesium tungsten oxide or lanthanum hexaboride. The content of cesium tungsten oxide in the cesium tungsten oxide-containing ink is arbitrary, but in one example, it is shown in the examples described later that good characteristics are obtained at a content rate of 0.5% by weight (weight percent) to 6% by weight. The content rate of lanthanum hexaboride in the lanthanum hexaboride-containing ink is also arbitrary, and in one example, it may be 0.05% by weight (weight percent) to 6% by weight, but it is shown in the examples described later that good characteristics are obtained at a content rate of 0.3% by weight. As a method for qualitatively analyzing lanthanum hexaboride (lanthanum boride), for example, the content of lanthanum hexaboride (LaB6) can be confirmed by the following method. (1) Mass Spectrometry (MS): Whether La and B are present, ratio of La and B Even when using a near-infrared absorbing ink containing both cesium tungstate and lanthanum hexaboride, the content rates of cesium tungstate and lanthanum hexaboride are similarly arbitrary. In any case, the preferable content rate can be changed according to the printing density (ink deposit). Here, the "content rate (wt%) of cesium tungstate" is the ratio of the weight of cesium tungstate contained in the ink to the total weight of the ink, Content rate (wt%) of cesium tungstate in the ink = {(weight of cesium tungstate) / (total weight of the ink)} × 100 which is represented by Similarly, the "content rate (wt%) of lanthanum hexaboride" is the ratio of the weight of lanthanum hexaboride contained in the ink to the total weight of the ink, Content rate (wt%) of lanthanum hexaboride in the ink = {(weight of lanthanum hexaboride) / (total weight of the ink)} × 100 which is represented by

[0035] FIG. 5 conceptually shows an example of the layer structure when the laminate shown in FIG. 1 is viewed at the A - A' cross-section cut along the line A - A' in FIG. 1 (viewed from below within the plane of the paper of FIG. 1. For showing the layer structure, each layer is depicted separately. The same applies to other figures showing the layer structure.).

[0036] The base material layer 9 is formed of a sheet-like base material (white sheet) with low visible light and near-infrared transmittance, which is made using materials such as PVC (polyvinyl chloride), PET-G (copolyester), PC (polycarbonate), PET (polyethylene terephthalate), PP (polypropylene), etc. Also, when the over-sheet layers 14, 15 are not used, the base material layer 9 may be a paper base material (such as high-quality paper, coated paper, etc.) (even when the over-sheet layers 14, 15 are used, it is possible to use the above paper base material as the base material layer 9).

[0037] The laser color-developing layer 10 is a transparent sheet-like layer containing a laser color-developing agent and is fused to the base material layer 9 by pressing. The laser color-developing layer 10 has the property of developing color when irradiated with laser light. The portion of the laser color-developing layer 10 irradiated with laser light changes in absorbency with respect to visible light and near-infrared light (in one example, by increasing the visible light absorbency and near-infrared light absorbency, it appears darker than other portions when viewed visually or observed with an infrared camera), and thus the portion can be recognized visually and by using an infrared camera. As the laser color-developing agent, as described in the specification of Patent No. 6167803, for example, coloring agents such as dyes and pigments, clays, etc. can be used. Specifically, yellow iron oxide, inorganic lead compounds, manganese violet, cobalt violet, mercury, cobalt, copper, nickel and other metal compounds, pearlescent pigments, silicon compounds, micas, kaolins, silica sand, diatomaceous earth, talc, titanium oxide-coated micas, tin dioxide-coated micas, antimony-coated micas, tin + antimony-coated micas, tin + antimony + titanium oxide-coated micas, etc. can be used alone or in combination of two or more (in the specification of Patent No. 6167803, paragraph

[0043] ). As a color-developing material that develops color with a low-output laser, in particular, bismuth-based compounds can be used at least. The bismuth compound is not particularly limited specifically, but for example, bismuth nitrate-based such as bismuth oxide, bismuth nitrate, bismuth oxynitrate, bismuth halides such as bismuth chloride, bismuth oxychloride, bismuth sulfate, bismuth acetate, bismuth citrate, bismuth hydroxide, bismuth titanate, etc. can be mentioned. Among them, from the viewpoint of easy availability and low cost, preferably, bismuth nitrate and bismuth hydroxide can be used. The bismuth-based compound can contain one or more compounds. In addition to the color-developing material containing at least a bismuth-based compound as an example, other than the bismuth compound, any color-developing material that develops color with laser light can be used in combination (in the specification of Patent No. 6167803, paragraph

[0044] ).Also, when using a color - forming material containing at least a bismuth - based compound as an example, a color - forming material that is further colored by laser light and / or an inorganic compound can be used to increase the color - forming efficiency. As the inorganic compound, it is possible to use metal oxides, composite oxides, metal salts, or one or more compounds thereof. Even when irradiated with low - output laser light, the inorganic compound can, in some cases, function as a color - forming material and / or function to increase the heat - generating efficiency to assist the color - formation of the color - forming material, or it is preferable to add an inorganic compound to function to increase the whiteness of a white ink containing a color - forming material and a white pigment (Patent No. 6167803, paragraph

[0045] ).

[0038] On the outermost top layer of the laminate 1, an oversheet layer (transparent sheet) 14 having visible light transmittance and near-infrared light transmittance is formed, and on the outermost bottom layer of the laminate 1, an oversheet layer (transparent sheet) 15 having visible light transmittance and near-infrared light transmittance is formed. For the oversheet layers 14 and 15, for example, two transparent PCs (polycarbonates) with a thickness of about 0.05 mm to 0.2 mm are prepared, and one sheet is laminated on each of the bottommost layer and the topmost layer of the laminate 1 before forming the oversheet layers 14 and 15, and the laminate 1 can be formed by applying heat and pressure to fuse them. When forming a colored ink layer 11 (or a fluorescent ink layer, a hologram layer, etc. The same applies in other descriptions) on the oversheet layer 14, before the above lamination of the oversheet layer 14, printing with a colored ink is performed on the oversheet layer 14 in advance to form the colored ink layer 11. Also, when forming a near-infrared light absorbing ink layer 13 and a colored ink layer 12 on the oversheet layer 15, before the above lamination of the oversheet layer 15, printing with a near-infrared light absorbing ink and a colored ink is performed on the oversheet layer 15 in advance to form the near-infrared light absorbing ink layer 13 and the colored ink layer 12. When forming a printing layer on the oversheet layers 14 and 15, for anti-counterfeiting purposes, it is preferably laminated so that the printing layer is disposed on the side of the base material layer 9. Also, when there is an oversheet layer, the printed information is printed inside the laminate, which also has the characteristic of being more difficult to forge. As another example, the laminate 1 before forming the oversheet layers 14 and 15 is laminated from above and below with any two transparent films (if necessary, printing with a colored ink, a near-infrared light absorbing ink, etc. is performed in advance on any one of each film, the base material layer 9, and the laser color developing layer 10), and the laminate 1 may be formed by adhering them using an adhesive between the layers. The fusion of the laser color developing layer 10 to the base material layer 9 is the same. As already described, forming the oversheet layers 14 and 15 is not essential, and only one of the oversheet layers 14 and 15 may be formed, or the laminate 1 may be manufactured without forming either of the oversheet layers. Note that laser marking on the laser color developing layer 10 is performed from the topmost layer side (the side of the oversheet layer 14) of the laminate 1.In addition, laser marking on the printed image 6 (near-infrared absorbing ink layer 13) is performed from the lowermost layer side of the laminate 1 (the side of the oversheet layer 15).

[0039] A colored ink layer 11 is formed on the oversheet layer 14 (it may also be on the laser color-developing layer 10). As described above, the colored ink layer 11 is formed by printing the mark 4 on the oversheet layer 14 (or on the laser color-developing layer 10) using a near-infrared transmissive colored ink. The method for forming the colored ink layer 11 is arbitrary. For example, printing methods such as letterpress printing, offset printing, silk screen printing, gravure printing, flexographic printing, inkjet printing, or any other arbitrary forming method can be used. In addition, instead of or in addition to the colored ink layer 11, a fluorescent ink layer 11 may be formed using a near-infrared transmissive fluorescent ink such as UV fluorescent medium B (manufactured by T&K TOKA), UV fluorescent medium Y (manufactured by T&K TOKA), UV fluorescent medium R (manufactured by T&K TOKA). The fluorescent ink layer 11 can be formed by printing or the like on the oversheet layer 14 in the same manner as the colored ink layer 11 using a fluorescent ink composition, and marks or the like can be printed in the same manner as in the case of colored ink printing. Alternatively, instead of or in addition to the colored ink layer 11 and the fluorescent ink layer 11, or in addition to at least one of these layers, a near-infrared transmissive hologram layer 11 such as a transparent hologram may be formed. The colored ink layer 11 may be formed on the front surface of the oversheet layer 14 (the surface opposite to the laser color-developing layer 10), on the back surface of the oversheet layer 14 (the surface on the laser color-developing layer 10 side), on the front surface of the laser color-developing layer 10 (the surface opposite to the base material layer 9), on the back surface of the laser color-developing layer 10 (the surface on the base material layer 9 side), or on two or more of these surfaces (the illustration is appropriately omitted). Note that the colored ink layer 11, the fluorescent ink layer 11, and the hologram layer 11 do not necessarily have to have near-infrared transmissivity. In the examples here, for the purpose of simplifying the figures showing the observed images, they are unified as layers having near-infrared transmissivity.

[0040] Also, on top of the oversheet layer 15 (it may also be on top of the base material layer 9), a colored ink layer 12 (or a fluorescent ink layer, a hologram layer, etc. The material and the forming method may be the same as those of the colored ink layer 11, or the fluorescent ink layer 11, or the hologram layer 11. The same applies to other descriptions.) is formed, and a near-infrared absorbing ink layer 13 is formed so as to at least partially overlap with the colored ink layer 12. The near-infrared absorbing ink layer 13 is formed by printing a printed image 6 on the oversheet layer 15 (or on the base material layer 9) using the near-infrared absorbing ink as described above. However, the near-infrared absorbing ink layer 13 may be formed by any forming method other than printing. For example, it may be a near-infrared absorbing layer (transparent sheet) containing a near-infrared absorbing material like the laser coloring layer 10. Also, it is not essential that the colored ink layer 12 and the near-infrared absorbing ink layer 13 at least partially overlap, and they may be formed completely separated on the oversheet layer 15 or on the base material layer 9. Further, when the colored ink layer 12 and the near-infrared absorbing ink layer 13 at least partially overlap, which layer is located on top is also arbitrary (see FIG. 6). The colored ink layer 12 and the near-infrared absorbing ink layer 13 may be formed on the front surface of the oversheet layer 15 (the surface opposite to the base material layer 9), on the back surface of the oversheet layer 15 (the surface on the side of the base material layer 9), on the back surface of the base material layer 9 (the surface opposite to the laser coloring layer 10), or on two or more of these surfaces (appropriate illustrations are omitted).

[0041] FIG. 6 conceptually shows another example of the layer structure when the laminate shown in FIG. 1 is viewed from the A-A' cross-section cut along the line A-A' in FIG. 1 (viewed from below within the plane of FIG. 1). As described above, when the colored ink layer 12 and the near-infrared absorbing ink layer 13 at least partially overlap, which layer is located on top is arbitrary, and the laminate 1 may have the layer configuration shown in FIG. 6 instead of the layer configuration shown in FIG. 5.

[0042] FIG. 7 conceptually shows still another example of the layer structure when the laminate shown in FIG. 1 is viewed in the A-A' cross-section cut along the line A-A' in FIG. 1 (viewed from below in the plane of the paper of FIG. 1). The colored ink layer 11 may be formed between the base material layer 9 and the laser color-developing layer 10, may be formed on the base material layer 9 by printing or the like as shown in FIG. 7, or may be formed on the surface of the laser color-developing layer 10 on the side of the base material layer 9 by printing or the like.

[0043] As an example of the method for manufacturing the laminate 1 shown in FIGS. 1 to 5, (1) A colored ink layer 11 (mark 4) is formed by printing using a colored ink on the oversheet layer 14, a near-infrared absorbing ink layer 13 (printed image 6) is formed by printing using a near-infrared absorbing ink on the oversheet layer 15, and a colored ink layer 12 (mark 5) is formed by printing using a colored ink on the base material layer 9. (2) In addition to the above layers, a laser color-developing layer 10 is also prepared, and the layers are laminated in the order shown in FIG. 5 and fused by a pressing process. (3) Laser marking is performed on the laser color-developing layer 10 from the surface of the obtained laminate on the side of the oversheet layer 14 to draw the person image 2 and the person identification information 3. (4) Laser marking is performed on the printed image 6 (near-infrared absorbing ink layer 13) from the surface of the laminate on the side of the oversheet layer 15 to draw the person image 7 and the person identification information 8. The laminate 1 can be manufactured by such a method. When manufacturing with the layer configuration of FIG. 6, in (1) of the above manufacturing method, the near-infrared absorbing ink layer 13 is formed by printing using a near-infrared absorbing ink on the base material layer 9 instead of the oversheet layer 15, and the colored ink layer 12 is formed by printing using a colored ink on the oversheet layer 15 instead of the base material layer 9 (the rest is the same as the manufacturing method of the layer configuration of FIG. 5). When manufacturing with the layer configuration of FIG. 7, the printing using the colored ink performed on the oversheet layer 14 in (1) above is performed on the base material layer 9 (the rest is the same as the manufacturing method of the layer configuration of FIG. 5).

[0044] (Method for authenticity determination) By comparing the visible light image and the near-infrared image of the laminate 1, the authenticity of the laminate 1 can be determined. Specifically, when the person image 2 recognizable as a visible light image (including an image obtained by viewing with the naked eye. The same applies to other embodiments.) and the person identified by the person identification information 3 match the person image 7 recognizable as a near-infrared image and the person identified by the person identification information 8, it can be determined that the laminate 1 is genuine as an identity card or the like. When the person image 2 recognizable as a visible light image and the person identified by the person identification information 3 do not match the person image 7 recognizable as a near-infrared image and the person identified by the person identification information 8, it can be determined that the laminate 1 is not genuine (a forgery) as an identity card or the like.

[0045] FIG. 8 is a diagram showing micro characters (near-infrared image) that can be seen when a part of a printed image with near-infrared absorbing ink shown in FIG. 4 is enlarged. As can be seen from the enlarged view of a part 16 of the printed image 6 shown in FIG. 8, the printed image 6 includes micro characters 17 (the micro characters 17 are omitted in FIG. 4. In subsequent figures, minute displays such as micro characters will be omitted as appropriate). Instead of micro characters, the printed image 6 may be printed including security designs such as colored patterns, minute symbols, relief patterns, etc., or these may be combined and printed. By including minute displays (displays of a size that cannot be visually recognized by the naked eye. In addition to micro characters, for example, minute characters, symbols, or figures may also be used. Note that the "micro characters" referred to here are not limited to characters in μm units (characters with a diameter, width, or height of less than 1 mm), and characters with a diameter, width, or height of 1 mm or more may also be referred to as "micro characters". The same applies to the sizes of other minute displays.) such as micro characters that are difficult to reproduce with a copying machine or the like (micro display printing), the forgery prevention effect of the laminate 1 can be enhanced. In particular, if micro characters with a line width and character size that are difficult to reproduce in laser marking (laser printing) described later are included, the forgery prevention effect of the laminate 1 will be extremely high.

[0046] FIG. 9 is a diagram (near-infrared image) showing micro characters visible when a part of a printed image with near-infrared absorbing ink shown in FIG. 4 and a part of a human image generated by laser marking (laser drawing) are enlarged respectively. Micro character 18 is a micro character formed during printing (micro display printing) using the near-infrared absorbing ink of printed image 6, and a part of it remains even after laser marking of human image 7. Micro character 19 is a micro character formed during printing using the near-infrared absorbing ink of printed image 6. In one example, printed image 6 is entirely formed by at least one of micro characters, colored patterns, fine symbols, relief patterns, etc. (security design. Note that the size of individual characters such as micro characters and fine symbols is arbitrary, but in one example, the maximum diameter, maximum width, or maximum height can be 1000 μm (micrometers).), and thus patterns such as human image 7 and person identification information 8 drawn by laser marking also become security designs when enlarged by a near-infrared camera or the like. By adopting such a configuration, the effect of preventing forgery and counterfeiting of laminate 1 can be further improved.

[0047] (Second Embodiment) FIG. 10 is a diagram (near-infrared image) showing micro characters generated by laser marking (laser printing) on the back surface of the laminate in the second embodiment of the present invention. The layer structure of laminate 1 in FIG. 10 may be the same as that in the first embodiment (see FIGS. 5 to 7), and micro character 20 is written by laser marking on near-infrared absorbing ink layer 13, and the only difference from the first embodiment is that person identification information 8 is not laser marked as in FIG. 4 (however, the content indicated by micro character 20 may be the same as the content indicated by person identification information 8 in FIG. 4).

[0048] (Third Embodiment) FIG. 11 is a diagram showing a near-infrared image of the back surface of the laminate in the third embodiment of the present invention. Different from the laminate 1 of the first embodiment, a mark 21 is printed on the base material 9 using a near-infrared absorbing ink so as to overlap with the mark 5 (see FIG. 3) by colored ink printing (near-infrared absorbing ink layer 13. However, the mark 21 may be formed using a near-infrared absorbing ink mixed with a colored ink. A layer formed using an ink in which other components such as a colored ink are added to the near-infrared absorbing ink is also referred to as a "near-infrared absorbing ink layer" here. The same applies to other embodiments.). Also, a portrait 22 is drawn by laser marking on the mark 21. Except for these points, the laminate in the third embodiment is the same as the laminate in the first embodiment, and the layer structure may also be the same in both embodiments.

[0049] (Fourth Embodiment) FIG. 12 is a diagram showing an observation image (visible light image) of the front surface of the laminate in the fourth embodiment of the present invention by visible light, FIG. 13 is a diagram showing an observation image (near-infrared image) of the front surface of the laminate by a near-infrared camera, FIG. 14 is a diagram showing an observation image (visible light image) of the back surface of the laminate under visible light (the surface that can be seen by turning the laminate over by rotating the laminate around the AX axis in FIG. 12. The same applies to other embodiments.), and FIG. 15 is a diagram showing an observation image (near-infrared image) of the back surface of the laminate by a near-infrared camera (note that the outer shape of the laminate is drawn for ease of viewing. The same applies to other figures.). FIG. 16 is a diagram conceptually showing an example of the layer structure when the laminate shown in FIG. 12 is viewed from the B-B' cross-section cut along the line B-B' in FIG. 12 (viewed from the right direction within the plane of FIG. 12). (Each layer is drawn separately to show the layer structure. Also, the colored ink layer (or fluorescent ink layer, hologram layer) 12 and the near-infrared absorption layer 13 on the back surface side are not exactly cut by the line B-B', but are drawn for the purpose of making the layer structure easier to understand. The same applies to other figures showing the layer structure.). FIG. 17 is a diagram conceptually showing another example of such a layer structure.

[0050] As a point different from the first embodiment described with reference to FIGS. 1 to 7, as shown in FIGS. 16 and 17, in the laminate 1 of the fourth embodiment, the base material layer is composed of a first base material layer 25 and a second base material layer 26 (the material etc. may be the same as that of the base material layer 9. Also, the base material layer 9 shown in FIG. 5 etc. may also be composed of a plurality of layers of sheets.), and a base material intermediate layer is provided as a layer (at least partially) sandwiched between the first base material layer 25 and the second base material layer 26. The first portion 24 of the base material intermediate layer is located between the first base material layer 25 and the second base material layer 26, and the second portion 23 of the base material intermediate layer protrudes from between the first base material layer 25 and the second base material layer 26. The second portion 23 of the base material intermediate layer is located at the end of the laminate 1, and this is used as a binding margin (tojishiro), and a booklet can be produced by sewing.

[0051] Such a base material intermediate layer can be provided by sandwiching the base material intermediate layer (at least partially) between the first base material layer 25 and the second base material layer 26 and then fusing it to the first base material layer 25 and the second base material layer 26 by heat pressing treatment. It may also be provided by adhering it to the first base material layer 25 and the second base material layer 26 using an adhesive. As the base material intermediate layer, a sheet made of any material such as paper, resin, cloth, non-woven fabric, etc. can be used. As an example, a fabric having a net-like structure as described in International Publication No. 2018 / 151238 can be mentioned.

[0052] As an example of the manufacturing method of the laminate 1 shown in FIGS. 12 to 16, (1) A colored ink layer 11 (mark 4) is formed by printing with colored ink on the oversheet layer 14, a near-infrared absorbing ink layer 13 (printed image 6) is formed by printing with near-infrared absorbing ink on the oversheet layer 15, and a colored ink layer 12 (mark 5) is formed by printing with colored ink on the first base material layer 25. (2) In addition to the above-mentioned layers, a second base material layer 26, a base material intermediate layer (23, 24), and a laser coloring layer 10 are also prepared, and the layers are laminated in the order shown in FIG. 16 and fused by pressing treatment. (3) Perform laser marking on the laser coloring layer 10 from the surface on the oversheet layer 14 side of the obtained laminate to draw the person image 2 and the person identification information 3. (4) Perform laser marking on the printed image 6 (near-infrared absorbing ink layer 13) from the surface on the oversheet layer 15 side of the laminate to draw the person image 7 and the person identification information 8. The laminate 1 can be manufactured by this method. When manufacturing with the layer structure of Fig. 17, in (1) of the above manufacturing method, the near-infrared absorbing ink layer 13 is formed by printing with near-infrared absorbing ink on the first base material layer 25 instead of the oversheet layer 15, and the colored ink layer 12 is formed by printing with colored ink on the oversheet layer 15 instead of the first base material layer 25 (otherwise, it is the same as the manufacturing method of the layer structure of Fig. 16).

[0053] (Method for authenticity determination) By comparing the visible light image and the near-infrared image of the laminate 1, the authenticity of the laminate 1 can be determined. Specifically, when the person identified by the person image 2 and the person identification information 3 recognizable as the visible light image matches the person identified by the person image 7 and the person identification information 8 recognizable as the near-infrared image, it can be determined that the laminate 1 is genuine as an identity card or the like. When the person identified by the person image 2 and the person identification information 3 recognizable as the visible light image does not match the person identified by the person image 7 and the person identification information 8 recognizable as the near-infrared image, it can be determined that the laminate 1 is not genuine (a fake) as an identity card or the like.

[0054] (Fifth Embodiment) FIG. 18 is a view showing an observation image (visible light image) of the front surface of the laminate in the fifth embodiment of the present invention by visible light (the lenticular lens is transparent but is drawn for the purpose of making the figure easier to view. Also, the display by laser marking on the laser color development layer 10 that can be seen under the lenticular lens is omitted). FIG. 19 is a view showing a visible light image of the front surface when the laminate is viewed in the direction of arrow C in FIG. 26 described later. FIG. 19A is a view showing a near-infrared image of the front surface when the laminate is viewed in the direction of arrow C in FIG. 26 described later. FIG. 20 is a view showing a visible light image of the front surface when the laminate is viewed in the direction of arrow D in FIG. 26. FIG. 20A is a view showing a near-infrared image of the front surface when the laminate is viewed in the direction of arrow D in FIG. 26. FIG. 21 is a view showing an observation image (visible light image) of the back surface of the laminate by visible light (the lenticular lens is transparent but is drawn for the purpose of making the figure easier to view.). FIG. 22 is a view showing a near-infrared image of the back surface when the laminate is viewed in the direction of arrow E in FIG. 26. FIG. 23 is a view showing a near-infrared image of the back surface when the laminate is viewed in the direction of arrow F in FIG. 26.

[0055] FIG. 24 conceptually shows an example of the layer structure when the A-A' cross-section obtained by cutting the laminate along the line A-A' in FIG. 18 is viewed (viewed from below within the plane of FIG. 18). (For showing the layer structure, each layer is drawn separately. Also, the colored ink layer (or fluorescent ink layer, hologram layer) 11 on the front surface side and the colored ink layer (or fluorescent ink layer, hologram layer) 12 on the back surface side are not exactly cut by the line A-A', but are drawn for the purpose of making the layer structure easier to understand. The same applies to other figures showing the layer structure.). FIG. 25 conceptually shows another example of the layer structure when the A-A' cross-section obtained by cutting the laminate shown in FIG. 18 along the line A-A' in FIG. 18 is viewed.

[0056] Unlike the first embodiment shown in FIG. 1 and the like, a lenticular lens 27 is formed in a partial area on the surface of the oversheet layer 14 opposite to the laser color developing layer 10. Further, a lenticular lens 31 is formed in an area of the surface of the oversheet layer 15 opposite to the near-infrared absorbing ink layer 13 and at least partially overlapping the near-infrared absorbing ink layer 13. The layer structures of FIGS. 24 and 25 may be the same as the layer structures of FIGS. 5 and 6 except that the lenticular lenses 27 and 31 are formed. Further, in all embodiments including the fifth embodiment, a colored ink layer 11 (or a fluorescent ink layer 11, or a hologram layer 11. The same applies to other embodiments) may be provided between the base material layer and the laser color developing layer 10 as in FIG. 7.

[0057] FIG. 26 conceptually shows an example of the layer structure (viewed from the right direction within the plane of FIG. 18) when the laminate shown in FIG. 18 is cut along line B-B' (FIG. 18 is drawn with each layer separated for clarity in showing the layer structure. Also, the colored ink layer (or fluorescent ink layer, hologram layer) 12, near-infrared absorption layer 13, and lenticular lens 31 on the back side are not exactly cut by line B-B', but are drawn for the purpose of making the layer structure easier to understand. The same applies to other figures showing the layer structure.). As shown in FIG. 26, when viewed from the direction as shown, the lenticular lenses 27 and 31, which are examples of a plurality of convex optical element portions, have a shape such that a plurality of convex lens portions appear to be arranged (along the vertical direction (line B-B') within the plane of FIG. 18). In FIG. 26, seven convex lens portions are drawn side by side in both the lenticular lenses 27 and 31, but this is a convenient display for simplifying the explanation of the structure of the lenticular lens. In one example, the lenticular lenses 27 and 31 can be formed to include more, for example, about 100 convex lens portions (the number of convex lens portions in the lenticular lenses 27 and 31 may be the same or different from each other). Alternatively, the number of convex lens portions may be made smaller, and generally, the lenticular lenses 27 and 31 can be formed to include any plurality of convex lens portions. A lenticular lens may be formed on only one of the oversheet layers 14 and 15. As methods for forming the lenticular lenses 27 and 31 on the oversheet layers 14 and 15, respectively, the already fabricated lenticular lenses 27 and 31 may be adhered onto the oversheet layers 14 and 15 with an adhesive or the like, or the oversheet layers 14 and 15 may be formed by heat and pressure so as to have a shape that functions as the lenticular lenses 27 and 31, or a lenticular lens base material may be formed on the oversheet layers 14 and 15 by a printing method and fixed by a method such as UV curing. The method for forming the lenticular lens 27 and the method for forming the lenticular lens 31 may be the same or different from each other.

[0058] When viewing (visually recognizing) a display such as a pattern or characters drawn by laser marking in an area within the laser color - forming layer 10 that at least partially overlaps with the lenticular lens 27 using visible light, different displays (visible - light images) can be seen depending on the viewing direction. In FIG. 26, when viewed in the direction of arrow C, the visible - light image shown in FIG. 19 can be seen, and when viewed in the direction of arrow D in FIG. 26, the visible - light image shown in FIG. 20 can be seen. In the examples of FIGS. 19 and 20, by laser marking with near - infrared laser light irradiated in the direction (angle) of arrow C in FIG. 26, the human - figure image 28 shown in FIG. 19 is drawn on the laser color - forming layer 10, and by laser marking with near - infrared laser light irradiated in the direction (angle) of arrow D in FIG. 26, the human - identification information 29 shown in FIG. 20 is drawn on the laser color - forming layer 10. In FIG. 26, the human - figure image 28 can be recognized by viewing the laser color - forming layer 10 from the direction of arrow C using a visible - light camera or an infrared camera, etc., and the human - identification information 29 can be recognized by viewing the laser color - forming layer 10 from the direction of arrow D in FIG. 26 using a visible - light camera or an infrared camera, etc. That is, the latent pattern can be visually recognized by changing the observation angle, and multiple - laser - image (MLI) of visible - light absorption is realized.

[0059] Also, when viewing the patterns, characters, etc. drawn by laser marking on the near-infrared absorbing ink layer 13 using a near-infrared camera or the like, different displays (near-infrared images) can be seen depending on the viewing direction. In FIG. 26, when viewed in the direction of arrow E, the near-infrared image shown in FIG. 22 can be seen, and when viewed in the direction of arrow F in FIG. 26, the near-infrared image shown in FIG. 23 can be seen. In the examples of FIGS. 22 and 23, a printed image 32 is printed on the base material layer 9 or on the oversheet layer 15 using a near-infrared absorbing ink so as to overlap with the lenticular lens 31 (near-infrared absorbing ink layer 13). By laser marking with near-infrared laser light in the direction (angle) of arrow E in FIG. 26, the human figure image 33 shown in FIG. 22 is drawn on the near-infrared absorbing ink layer 13, and by laser marking with near-infrared laser light in the direction (angle) of arrow F in FIG. 26, the human identification information 34 shown in FIG. 23 is drawn on the near-infrared absorbing ink layer 13. In FIG. 26, the human figure image 33 can be recognized by viewing the near-infrared absorbing ink layer 13 from the direction of arrow E using a near-infrared camera or the like, and the human identification information 34 can be recognized by viewing the near-infrared absorbing ink layer 13 from the direction of arrow F in FIG. 26 using a near-infrared camera or the like. That is, the latent pattern can be recognized by changing the observation angle, and the MLI with near-infrared absorption is realized.

[0060] FIG. 27 is a diagram conceptually explaining the principle of lenticular (it is not necessary to match the specific configuration described with FIGS. 18 to 26). When looking at the laser color - developing layer 10 through the lenticular lens 27 from the first position P1 by means of a visible - light camera, visual inspection, etc., each pattern drawn on the plurality of printing portions IM1 is synthesized, and a first display (pattern) such as a person image 28 can be recognized. When looking at the laser color - developing layer 10 through the lenticular lens 27 from the second position P2 by means of a visible - light camera, visual inspection, etc., each pattern drawn on the plurality of printing portions IM2 is synthesized, and a second display (character) such as person identification information 29 can be recognized. The same applies to the case of near - infrared display. When looking at the near - infrared - absorbing ink layer 13 through the lenticular lens 31 from the first position P1 by means of a near - infrared camera, etc., each pattern drawn on the plurality of printing portions IM1 is synthesized, and a first display (pattern) such as a person image 33 can be recognized. When looking at the near - infrared - absorbing ink layer 13 through the lenticular lens 31 from the second position P2 by means of a near - infrared camera, etc., each pattern drawn on the plurality of printing portions IM2 is synthesized, and a second display (character) such as person identification information 34 can be recognized.

[0061] As an example of the manufacturing method of the laminate 1 shown in FIGS. 18 to 24, (1) A colored ink layer 11 (mark 4) is formed by printing with a colored ink on the over - sheet layer 14, a near - infrared - absorbing ink layer 13 (printed image 32) is formed by printing with a near - infrared - absorbing ink on the over - sheet layer 15, and a colored ink layer 12 (mark 30) is formed by printing with a colored ink on the base material layer 9. (2) In addition to the above - mentioned layers, a laser color - developing layer 10 is also prepared, and the layers are laminated in the order shown in FIG. 24, and fusion is performed by heat - pressing using a press plate with unevenness capable of forming a lenticular lens, thereby forming lenticular lenses 27 and 31. (3) Perform laser marking on the laser coloring layer 10 from the surface of the obtained laminate on the oversheet layer 14 side to draw the person image 2 and the person identification information 3. Further, by laser marking with near-infrared laser light irradiated in the direction (angle) of arrow C in FIG. 26, the person image 28 is drawn on the laser coloring layer 10, and by laser marking with near-infrared laser light irradiated in the direction (angle) of arrow D in FIG. 26, the person identification information 29 is drawn on the laser coloring layer 10. (4) From the surface of the oversheet layer 15 side of the above laminate, by laser marking with near-infrared laser light irradiated in the direction (angle) of arrow E in FIG. 26, the person image 33 is drawn on the near-infrared absorbing ink layer 13 (printed image 32), and by laser marking with near-infrared laser light irradiated in the direction (angle) of arrow F in FIG. 26, the person identification information 34 is drawn on the near-infrared absorbing ink layer 13 (printed image 32). The laminate 1 can be manufactured by such a method. When manufacturing with the layer structure of FIG. 25, in (1) of the above manufacturing method, the near-infrared absorbing ink layer 13 is formed by printing with near-infrared absorbing ink on the base material layer 9 instead of the oversheet layer 15, and the colored ink layer 12 is formed by printing with colored ink on the oversheet layer 15 instead of the base material layer 9 (the rest is the same as the manufacturing method of the layer structure of FIG. 24).

[0062] (Genuine and fake determination method) By comparing the visible light image and the near-infrared image of the laminate 1, the authenticity determination of the laminate 1 can be performed. Specifically, when the person image 2 recognizable as a visible light image, the person specified by the person identification information 3, the person image 33 recognizable as a near-infrared image, the person specified by the person identification information 34, the person image 28 recognizable as a visible light image, and the person specified by the person identification information 29 all match, it can be determined that the laminate 1 is genuine as an identity card or the like. When at least a part of the person image 2 recognizable as a visible light image, the person specified by the person identification information 3, the person image 33 recognizable as a near-infrared image, the person specified by the person identification information 34, the person image 28 recognizable as a visible light image, and the person specified by the person identification information 29 do not match, it can be determined that the laminate 1 is not genuine (a fake) as an identity card or the like.

[0063] (Sixth Embodiment) FIG. 28 is a diagram showing an observation image (visible light image) of the front surface of the laminate in the sixth embodiment of the present invention under visible light. FIG. 29 is a diagram showing an observation image (near-infrared image) of the front surface of the laminate by a near-infrared camera. FIG. 30 is a diagram showing an observation image (visible light image) of the back surface of the laminate (the surface that can be seen by turning the laminate over by rotating it around the AX axis in FIG. 28. The same applies to other embodiments.) under visible light. FIG. 31 is a diagram showing an observation image (near-infrared image) of the back surface of the laminate by a near-infrared camera. FIG. 32 is a diagram conceptually showing an example of the layer structure when the laminate shown in FIG. 28 is viewed from the A-A' cross-section cut along the line A-A' in FIG. 28 (viewed from below in the plane of FIG. 28). (For the purpose of showing the layer structure, each layer is drawn separately. Also, the colored ink layer (or fluorescent ink layer, hologram layer) 11 on the front surface side and the colored ink layer (or fluorescent ink layer, hologram layer) 12 on the back surface side are not exactly cut by the line A-A', but are drawn for the purpose of making the layer structure easier to understand. The same applies to other diagrams showing the layer structure.) FIG. 33 is a diagram conceptually showing another example of the layer structure when the laminate shown in FIG. 28 is viewed from the A-A' cross-section cut along the line A-A' in FIG. 28. In the base material layer 9, a clear window 35 made of a transparent material such as PVC (polyvinyl chloride), PET-G (amorphous polyester), PC (polycarbonate), PET (polyethylene terephthalate), PP (polypropylene), etc. is formed (see FIG. 28 for the two-dimensional shape. In the configurations of FIGS. 32 and 33, the clear window 35 penetrates the base material layer 9 and the laser coloring layer 10.). In one example, a part of the base material layer 9 and the laser coloring layer 10 may be opened according to the shape of the clear window 35, and a liquid transparent resin having visible light transmissivity and near-infrared light transmissivity may be poured into the resulting space and cured to produce the clear window 35. Alternatively, a solid transparent resin having visible light transmissivity and near-infrared light transmissivity with the same size as the opened part of the base material layer 9 and the laser coloring layer 10 may be fitted to produce it. Regarding the configuration other than the configuration related to the clear window 35, the laminate of the sixth embodiment may be the same as the laminate of the first embodiment.Further, similar laser coloring layers 10 may be provided on both the first surface and the second surface of the base material layer 9 (both on the surface of the base material layer 9 on the oversheet layer 14 side and on the surface on the oversheet layer 15 side). In this case, the opening penetrates through the base material layer 9, the laser coloring layer 10 on the first surface side, and the laser coloring layer 10 on the second surface side, and the clear window 35 provided here also penetrates through the base material layer 9 and the two laser coloring layers 10. By adopting such a configuration, printing by laser coloring can be performed on both the front and back surfaces of the laminate 1, so that the information that can be written increases. In addition, by providing the clear window portion, it can be made difficult to counterfeit. Furthermore, by providing the clear window portion, for example, a part of the laser coloring layer 10 is opened, and a clear window portion having a near-infrared absorbing ink layer 13 is provided in the space generated thereby. In one example, since the near-infrared absorbing ink layer 13 and the laser coloring layer 10 exist on the same surface, laser marking (drawing, printing, etc.) can be performed simultaneously, and the manufacturing process becomes simple.

[0064] In the laminate 1 of the sixth embodiment, a near-infrared absorbing ink layer 13 is formed so as to overlap the clear window 35 (FIGS. 32 and 33). Therefore, when looking at the clear window 35 from above using a near-infrared camera or the like (defining the direction from the oversheet layer 15 toward the oversheet layer 14 in the layer structure of FIGS. 32 and 33 as the "upward direction" and the opposite direction as the "downward direction". The same applies to other embodiments. See also FIG. 28. Here, the clear window 35 is viewed from further above the oversheet layer 14.), the printed image 6 printed as the near-infrared absorbing ink layer 13 and the portrait image 7 drawn on the printed image 6 by laser marking can be recognized (FIGS. 29 and 31). In addition, in the space formed by cutting out a part of the base material layer 9 and the laser coloring layer 10 where the clear window 35 should be formed, the above-described hologram layer as an embedded hologram or some security display may be arranged (these also penetrate through the base material layer 9 and the laser coloring layer 10).

[0065] As an example of the manufacturing method of the laminate 1 shown in FIGS. 28 to 32, (1) Form a colored ink layer 11 (mark 4) by printing with a colored ink on the oversheet layer 14, and form a colored ink layer 12 (mark 5) by printing with a colored ink on the oversheet layer 15. (2) Fuse the base material layer 9 and the laser color-developing layer 10 to each other by pressing, cut out the portion where the clear window 35 is to be formed, and fit a transparent resin into the space generated by the cutting to provide the clear window 35. Further, form a near-infrared absorbing ink layer 13 (printed image 6) on the exposed surface of the clear window 35 on the side of the laser color-developing layer 10 by printing with a near-infrared absorbing ink. (3) Stack the above layers in the order shown in Fig. 32 and fuse them by pressing. (4) Perform laser marking on the laser color-developing layer 10 from the surface of the obtained laminate on the side of the oversheet layer 14 to draw the person image 2 and the person identification information 3. (5) Perform laser marking on the printed image 6 (near-infrared absorbing ink layer 13) from the surface of the above laminate on the side of the oversheet layer 14 or the surface on the side of the oversheet layer 15 to draw the person image 7. The laminate 1 can be manufactured by such a method. When manufacturing with the layer structure of Fig. 33, in (2) of the above manufacturing method, form the near-infrared absorbing ink layer 13 by printing with a near-infrared absorbing ink on the exposed surface on the side of the base material layer 9 instead of on the side of the laser color-developing layer 10 of the clear window 35 (the rest is the same as the manufacturing method with the layer structure of Fig. 32).

[0066] (Method for authenticity determination) By comparing the visible light image and the near-infrared image of the laminate 1, the authenticity of the laminate 1 can be determined. Specifically, when the person identified by the person image 2 and the person identification information 3 that can be recognized as the visible light image matches the person identified by the person image 7 that can be recognized as the near-infrared image, it can be determined that the laminate 1 is genuine as an identity card or the like. When the person identified by the person image 2 and the person identification information 3 that can be recognized as the visible light image does not match the person identified by the person image 7 that can be recognized as the near-infrared image, it can be determined that the laminate 1 is not genuine (a fake) as an identity card or the like.

[0067] (Seventh Embodiment) FIG. 34 is a diagram showing an observation image (visible light image) of the front surface of the laminate in the seventh embodiment of the present invention under visible light, and FIG. 35 is a diagram showing an observation image (near-infrared image) of the front surface of the laminate in the seventh embodiment of the present invention by a near-infrared camera (for the purpose of making the figure easier to view, the outer shape of the laminate is drawn. The same applies to other figures.), FIG. 36 is a diagram showing an observation image (visible light image) of the back surface of the laminate in the seventh embodiment of the present invention under visible light (the surface that can be seen by turning the laminate over by rotating the laminate around the AX axis in FIG. 34. The same applies to other embodiments.), FIG. 37 is a diagram showing an observation image (near-infrared image) of the back surface of the laminate in the seventh embodiment of the present invention by a near-infrared camera (for the purpose of making the figure easier to view, the outer shape of the laminate is drawn. The same applies to other figures.), FIG. 38 is a diagram conceptually showing an example of the layer structure when the laminate shown in FIG. 34 is viewed from the B-B' cross-section cut along the B-B' line in FIG. 34 (viewed from the right direction within the plane of FIG. 34). (Each layer is drawn separately to show the layer structure. Also, the colored ink layers (or fluorescent ink layers, hologram layers) 11 and 12 on the front surface side and the back surface side are not exactly cut by the B-B' line, but are drawn for the purpose of making the layer structure easier to understand. The same applies to other figures showing the layer structure.), FIG. 39 is a diagram showing a booklet formed using the laminate in the seventh embodiment of the present invention.

[0068] Similar to the laminate 1 described with reference to FIG. 12 and the like, the laminate 1 in FIGS. 34 also includes a base material intermediate layer. As shown in FIG. 38, a part of the laminated structure composed of the first base material layer 25, the base material intermediate layers (23, 24), the second base material layer 26, and the laser color developing layer 10 is cut out, and a clear window 35 is provided in the resulting space. Using the second part 23 of the base material intermediate layer (protruding from between the first base material layer 25 and the second base material layer 26) as a binding margin, the laminate 1 (sheet) is bound to other sheets 38, 39, 40, thereby constituting a booklet 100. Further, in a region overlapping the clear window 35, a printed image 6 is formed by printing with a near-infrared absorbing ink (near-infrared absorbing ink layer 13 in FIG. 38. In this embodiment, the printed image 6 is assumed to be a solid print of the region overlapping the clear window 35 with a near-infrared absorbing ink.), and a portrait 7 is drawn by laser marking.

[0069] As an example of the method for manufacturing the laminate 1 shown in FIGS. 34 to 38, (1) A colored ink layer 11 (mark 4) is formed by printing with a colored ink on the over-sheet layer 14, and a colored ink layer 12 (mark 5) is formed by printing with a colored ink on the over-sheet layer 15. (2) The first base material layer 25, the second base material layer 26, the base material intermediate layers (23, 24), and the laser color developing layer 10 are laminated in the order shown in FIG. 38, fused by pressing, the portion where the clear window 35 is to be formed is cut out, and a transparent resin is fitted into the resulting space to provide the clear window 35. Further, a near-infrared absorbing ink layer 13 (printed image 6) is formed by printing with a near-infrared absorbing ink on the exposed surface of the clear window 35 on the side of the laser color developing layer 10. (3) The above layers are laminated in the order shown in FIG. 38 and fused by pressing. (4) Laser marking is performed on the laser color developing layer 10 from the surface of the obtained laminate on the side of the over-sheet layer 14 to draw the portrait 2 and the person identification information 3. (5) Laser marking is performed on the printed image 6 (near-infrared absorbing ink layer 13) from the surface on the over-sheet layer 14 side or the over-sheet layer 15 side of the laminate to draw a portrait 7. The laminate 1 can be produced by such a method. By binding this laminate with another sheet using the second portion 23 of the base material intermediate layer as a binding margin, a booklet 100 can be produced.

[0070] (Genuine / Fake Judgment Method) By comparing the visible light image and the near-infrared image of the laminate 1, the authenticity of the laminate 1 can be judged. Specifically, when the person identified by the portrait 2 recognizable as a visible light image and the person identification information 3 matches the person identified by the portrait 7 recognizable as a near-infrared image, it can be determined that the laminate 1 is genuine as an identity card or the like. When the person identified by the portrait 2 recognizable as a visible light image and the person identification information 3 does not match the person identified by the portrait 7 recognizable as a near-infrared image, it can be determined that the laminate 1 is not genuine (a fake) as an identity card or the like.

[0071] FIG. 40 is a diagram schematically showing the configuration of a laser marker device for performing laser marking (drawing, printing, etc.) described so far. The laser marker device 45 includes a control unit 46, a storage unit 47, a drive (scanning) unit 48, a laser light irradiation unit 49, and the like. While the head of the laser light irradiation unit 49 is driven by the drive unit 48, near-infrared laser light is irradiated from the head to the near-infrared absorption layer, whereby the above-described laser marking is performed on the near-infrared absorption layer (near-infrared absorbing ink layer 13) or the laser coloring layer 10. In the operation of such a laser marker device 45, a control unit 46 (a separate computer outside the laser marker device 45 can also function as the control unit 46) provided with various control circuits such as a CPU or an embedded control circuit controls a drive unit 48 which is a drive device provided with a motor or the like. As described above, while driving the head of the laser light irradiation unit 49 toward the near-infrared absorbing ink layer 13 or the laser coloring layer 10 (moving (scanning) the head), the laser light irradiation unit 49 (in one example, a laser light irradiation device including a Nd:YAG laser which is a device for generating laser light with a laser wavelength of 1064 nm and including various devices for irradiating the target with laser light such as a head) irradiates near-infrared laser light (which may be a near-infrared laser beam) from the head toward the near-infrared absorption layer or the laser coloring layer 10. Note that the storage unit 47 provided with a storage device such as a semiconductor memory and a magnetic disk stores various data for the control unit 46 to appropriately read and use for controlling the operation of the laser marker device 45, such as characters and images to be drawn by laser marking. The laser marker device 45 draws the characters, images, etc. stored in the storage unit 47 on the near-infrared absorption layer or the laser coloring layer 10. Since there are many known laser marker devices, no further detailed description will be given here.

[0072] (Examples of Near-Infrared Absorbing Ink) The experimental results of various laminates (offset prints) prepared using tungsten oxide cesium-containing ink and lanthanum hexaboride-containing ink as near-infrared absorbing inks that can be used in the present invention will be described while comparing them with the experimental results of an offset print prepared using ytterbium oxide-containing ink as a comparative example.

[0073] (Comparative Example 1) An ink having a ytterbium oxide content of 25% by weight was prepared by mixing ytterbium(III) oxide, 3N5 powder, and an ink vehicle containing monomers, synthetic resins, and other non-infrared absorbing materials so that the weight ratio of ytterbium oxide to the ink vehicle was 25:75. Using the thus-prepared ytterbium oxide-containing ink, a part of a region of high-quality paper as a substrate was printed by an offset printing machine (IGT C1 for offset printing suitability test machine, manufactured by IGT Testing Systems). The obtained printed matter was used as the laminate of Comparative Example 1, and was photographed with a VSC8000 (manufactured by Foster and Freeman), an infrared visualization device, with a filter that cuts light having a wavelength of 925 nm or less attached to the camera lens of the device.

[0074] (Example 1) Cesium tungsten oxide Cs 0.33 An ink having a cesium tungsten oxide content of 2% by weight was prepared by mixing a dispersion containing WO3 and an ink vehicle similar to that in Comparative Example 1 containing monomers, synthetic resins, and other non-infrared absorbing materials so that the weight ratio of cesium tungsten oxide to all other components was 2:98. Using the thus-prepared cesium tungsten oxide-containing ink, a part of a region of high-quality paper as a substrate was printed by an offset printing machine (IGT C1 for offset printing suitability test machine, manufactured by IGT Testing Systems). The obtained printed matter was used as the laminate of Example 1, and was photographed with a VSC8000 (manufactured by Foster and Freeman), an infrared visualization device, with a filter that cuts light having a wavelength of 925 nm or less attached to the camera lens of the device.

[0075] In Comparative Example 1 and Example 1, infrared photographs of the ytterbium oxide-containing ink and the cesium tungsten oxide-containing ink produced were taken respectively with the above infrared camera, and infrared photographs of the respective printed materials offset-printed as described above using the respective inks were taken with the above infrared camera, as shown in FIG. 41. From the photographs of the respective inks, it can be understood that both the ytterbium oxide-containing ink and the cesium tungsten oxide-containing ink exhibit near-infrared absorbency. However, near-infrared absorbency could not be visually recognized in the printed material offset-printed with the ytterbium oxide-containing ink. On the other hand, in the printed material offset-printed with the cesium tungsten oxide-containing ink having a low content, a difference in brightness could be visually recognized between the unprinted area and the printed area, and it was confirmed that the printed area had near-infrared absorbency.

[0076] The above experimental results are summarized in the following table.

Table 1

[0077] In the above table, the “film thickness” refers to the film thickness of the ytterbium oxide-containing ink layer or the cesium tungsten oxide-containing ink layer formed by offset printing. These are reference values assuming typical film thicknesses formed in offset printing, not measured values. The film thickness formed in the offset printing in each of the following examples is also estimated to be about 1 μm to about 3 μm. Note that experiments were conducted under the condition that conditions such as printing density were the same for all examples in this specification, and theoretically, the film thickness is considered to be the same. Also, the “infrared absorption rate” in Example 1 is a value obtained using the reflectance measured with a JASCO V-670 ultraviolet-visible near-infrared spectrophotometer (manufactured by JASCO Corporation) (the reflectance is the ratio of the intensity of the reflected light when the irradiated light is reflected from the surface of the printed material, which is the ratio of the intensity of the reflected light from the surface of the target printed material to the intensity of the reflected light from the surface of the reference substrate (reference portion) serving as a reference).) (absorption rate (%) = 100 - reflectance (%))

[0078] Next, offset printing was performed using a near-infrared absorbing ink with a cesium tungsten oxide (Cs 0.33 WO3) content (content ratio) of 2% by weight on various base sheets. Laser printing was performed on each of the produced printed materials using a laser marker device, and the reflectance of electromagnetic waves in the wavelength range of visible light to near-infrared light was measured for the printed and unprinted portions. In the following examples, the "reflectance" is, as in Example 1, the ratio of the intensity of the reflected light when the irradiated light is reflected from the surface of the printed material, and is the ratio of the intensity of the reflected light from the surface of the target printed material to the intensity of the reflected light from the surface of the reference base material (reference portion) (a value obtained by measurement using a JASCO V-670 ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation)). The "reflectance" in the above-mentioned Example 1 and the following Examples 2 to 11 can be generally defined by the following formula. Reflectance (%) of the target portion (target surface) = {(Intensity of reflected light from the target portion (target surface)) / (Intensity of reflected light from the reference portion (reference surface))} × 100

[0079] (Example 2) A dispersion containing cesium tungsten oxide Cs 0.33 WO3, monomers, synthetic resins, auxiliaries, etc. were mixed so that the weight ratio of cesium tungsten oxide to all other components was 2:98, thereby preparing an ink with a cesium tungsten oxide content of 2% by weight. Using the thus-prepared cesium tungsten oxide-containing ink, printing was performed on a PC (polycarbonate) sheet as the base material using an offset printing machine (IGT C1 offset printing suitability tester (manufactured by IGT Testing Systems)). The obtained printed material was used as the laminate of Example 2, and the reflectance of visible light to near-infrared light at a wavelength of 400 nm to 2000 nm on the printed surface before laser printing was measured using a JASCO V-670 ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation). Furthermore, as a laser marker device, Using TIFF0007694581000002.tif977, laser printing was performed on the above printing surface with a laser beam from a Nd:YAG laser with a wavelength of 1064 nm. The reflectance of the laser-printed portion in the visible to near-infrared range from 400 nm to 2000 nm was measured using a JASCO V-670 ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation).

[0080] (Example 3) Cesium tungstate Cs 0.33 A dispersion containing WO3 was mixed with monomers, synthetic resins, auxiliaries, etc. so that the weight ratio of cesium tungstate to all other components was 2:98, thereby preparing an ink with a cesium tungstate content of 2% by weight. Using the thus-prepared cesium tungstate-containing ink, printing was performed on a PET-G (copolyester) sheet as a substrate with an offset printing machine (IGT C1 for offset printing suitability testing machine, manufactured by IGT Testing Systems). The obtained printed matter was used as the laminate of Example 3, and the reflectance of the printing surface before laser printing in the visible to near-infrared range from 400 nm to 2000 nm was measured using a JASCO V-670 ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation). Furthermore, as a laser marker device, Using TIFF0007694581000003.tif977, laser printing was performed on the above printing surface with a laser beam from a Nd:YAG laser with a wavelength of 1064 nm. The reflectance of the laser-printed portion in the visible to near-infrared range from 400 nm to 2000 nm was measured using a JASCO V-670 ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation).

[0081] (Example 4) Cesium tungstate Cs 0.33A dispersion containing WO3, monomers, synthetic resins, auxiliaries, etc. were mixed so that the weight ratio of cesium tungstate to all other components was 2:98, thereby preparing an ink with a cesium tungstate content of 2% by weight. Using the cesium tungstate-containing ink thus prepared, printing was performed on a PVC (polyvinyl chloride) sheet as the substrate using an offset printing machine (IGT C1 for offset printing suitability test machine, manufactured by IGT Testing Systems). The obtained printed matter was used as the laminate of Example 4, and the reflectance of visible light to near-infrared light at wavelengths from 400 nm to 2000 nm on the printed surface before laser printing was measured using a JASCO V-670 ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation). Furthermore, as a laser marker device, TIFF0007694581000004.tif977 was used, and laser printing was performed on the above printed surface with a laser beam from a Nd:YAG laser with a wavelength of 1064 nm. The reflectance of visible light to near-infrared light at wavelengths from 400 nm to 2000 nm of the laser-printed portion was measured using a JASCO V-670 ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation).

[0082] The measurement results of the reflectance performed in Examples 2 to 4 above are shown in FIG. 42. Also, the measurement results of the reflectance performed in Example 2 are shown in FIG. 43, the measurement results of the reflectance performed in Example 3 are shown in FIG. 44, and the measurement results of the reflectance performed in Example 4 are shown in FIG. 45, respectively, extracted from the graph of FIG. 42 and shown. In the graphs of FIGS. 42 to 45, the value on the horizontal axis is the wavelength (nm) of the electromagnetic wave, and the value on the vertical axis is the reflectance (%) of the electromagnetic wave with the wavelength indicated by the value on the horizontal axis on the printed surface or the laser-printed portion.

[0083] As is clear from the graphs of FIGS. 42 to 45, it can be seen that the reflectance increases (the absorption rate decreases) in the near-infrared region by laser printing regardless of the substrate used. Although the increase width varies depending on the wavelength on the horizontal axis, in the near-infrared region of 780 nm to 2000 nm, it can be read that the reflectance has increased by at least 5% or more, generally 10% to 15% or more, due to laser printing. Also, as a general trend, the change in reflectance before and after laser printing in the visible light wavelength range is smaller compared to the change in reflectance before and after laser printing in the near-infrared region. Therefore, it is considered that laser printing can be used to draw characters, images, etc. that are relatively difficult to visually recognize with the naked eye or a general camera.

[0084] Next, offset printing was performed on high-quality paper as a substrate sheet using six types of near-infrared absorbing inks having different cesium tungsten oxide (Cs 0.33 WO3) contents (content ratios) ranging from 0.5% by weight to 6% by weight, and the reflectance of electromagnetic waves in the wavelength range of visible light to near-infrared light of the printed surface (near-infrared absorbing ink layer) in each of the produced printed matters was measured. Note that the definition of reflectance and the equipment used for reflectance measurement are the same as those in Examples 1 to 4 described above.

[0085] (Examples 5 to 10) Cesium tungsten oxide Cs 0.33 A dispersion containing WO3, monomers, synthetic resins, auxiliaries, etc., with the weight ratio of cesium tungsten oxide to all other components being: (Example 5) 0.5:99.5 (Example 6) 1:99 (Example 7) 1.3:98.7 (Example 8) 2:98 (Example 9) 3:97 (Example 10) 6:94 By mixing them so as to obtain the following, six types of inks with a cesium tungsten oxide content of 0.5% by weight to 6% by weight were prepared. Using each of the cesium tungsten oxide-containing inks thus prepared, printing was performed on the above-mentioned high-quality paper sheet as the base material using an offset printing machine (IGT C1 for offset printing suitability test, manufactured by IGT Testing Systems). The six types of printed materials obtained were used as the laminates of Examples 5 to 10, and the reflectance of visible light to near-infrared light at wavelengths from 400 nm to 2000 nm was measured using a JASCO V-670 ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation).

[0086] The measurement results of the reflectance performed in Examples 5 to 10 above are shown in FIG. 46. In the graph of FIG. 46, the value on the horizontal axis is the wavelength (nm) of the electromagnetic wave, and the value on the vertical axis is the reflectance (%) on the printed surface of the electromagnetic wave with the wavelength indicated by the value on the horizontal axis. It can be seen that at least in the near-infrared wavelength range, the higher the content of cesium tungsten oxide, the lower the reflectance at the same wavelength. A similar tendency can also be read in the visible light wavelength range. That is, the higher the content of cesium tungsten oxide in the ink, the easier it is to recognize the image offset-printed using the ink with a near-infrared camera or the like. However, in this case, since the visible light reflectance also decreases, the possibility of visual recognition with the naked eye, a general camera, etc. also increases. Therefore, it is considered preferable to select an appropriate cesium tungsten oxide content in consideration of security.

[0087] Next, offset printing was performed using an infrared-absorbing ink with a lanthanum hexaboride (LaB6) content (content rate) of 0.3 wt% on PC (polycarbonate) as a base sheet. Laser printing was performed on the produced printed matter using a laser marker device, and the reflectance of electromagnetic waves in the wavelength range of visible light to near-infrared light was measured for the printed part and the non-printed part, respectively. Also in this example, the reflectance is the ratio of the intensity of the reflected light when the irradiated light is reflected on the surface of the printed matter, and is the ratio of the intensity of the reflected light from the surface of the target printed matter to the intensity of the reflected light from the surface of the base material (reference part) used as a reference (a value obtained by measurement using a JASCO V-670 ultraviolet-visible near-infrared spectrophotometer (manufactured by JASCO Corporation)).

[0088] (Example 11) A dispersion containing lanthanum hexaboride (LaB6), monomers, synthetic resins, auxiliaries, etc. were mixed so that the weight ratio of lanthanum hexaboride to all other components was 0.3:99.7, thereby producing an ink with a lanthanum hexaboride content of 0.3 wt%. Using the thus-produced lanthanum hexaboride-containing ink, printing was performed on a PC (polycarbonate) sheet as a base material using an offset printing machine (IGT C1 for offset printing suitability test machine (manufactured by IGT Testing Systems)). The obtained printed matter was used as the laminate of Example 11, and the reflectance of visible light to near-infrared light at a wavelength of 400 nm to 2000 nm on the printed surface before laser printing was measured using a JASCO V-670 ultraviolet-visible near-infrared spectrophotometer (manufactured by JASCO Corporation). Furthermore, as a laser marker device, TIFF0007694581000005.tif977 was used, and laser printing was performed on the above printed surface with a laser beam from a Nd:YAG laser with a wavelength of 1064 nm. The reflectance of visible light to near-infrared light at a wavelength of 400 nm to 2000 nm for the laser-printed part was measured using a JASCO V-670 ultraviolet-visible near-infrared spectrophotometer (manufactured by JASCO Corporation).

[0089] The measurement results of the reflectance obtained in Example 11 above are shown in Fig. 47. In the graph of Fig. 47, the value on the horizontal axis is the wavelength (nm) of the electromagnetic wave, and the value on the vertical axis is the reflectance (%) of the electromagnetic wave with the wavelength indicated on the horizontal axis on the printed surface or the laser-printed portion.

[0090] As is apparent from the graph of Fig. 47, it can be seen that the reflectance increases (the absorption rate decreases) in the near-infrared region by laser printing. Although the rising width varies depending on the wavelength on the horizontal axis, it can be read that the reflectance rises by approximately 5% to 14% by laser printing in the near-infrared region of 780 nm to 1400 nm. Also, as a general tendency, the change in reflectance before and after laser printing in the wavelength range of visible light is smaller than the change in reflectance before and after laser printing in the near-infrared region of about 800 nm to 1200 nm. Therefore, it is considered that characters, images, etc. that are relatively difficult to visually recognize with the naked eye or a general camera can be drawn by laser printing.

[0091] (An example of use) In one example, the laminate in each of the above-described embodiments and examples can be used as a printed matter such as an identity certificate with high security. In Fig. 1, by comparing the portrait 2 printed with colored ink, the personal identification information 3 (visually recognizable with the naked eye), the portrait 7 of a person drawn by laser marking in the printed image 6 with near-infrared absorbing ink, and the personal identification information 8 (recognizable with an infrared camera, etc.), it is possible to determine whether the person indicated by the portrait 2 and the personal identification information 3 (visible information) matches the person indicated by the portrait 7 and the personal identification information 8 (infrared information). Thus, it is possible to perform authenticity determination of an identity certificate, etc. (if they match, it can be determined that the identity certificate, etc. is genuine, and if they do not match, it can be determined that the identity certificate, etc. is not genuine.), and if it is forged, it can be detected. The pattern drawn by the laser may not be a monotonous pattern such as a barcode, number, or two-dimensional code, but may be a portrait of a person as described above. Also, by combining with security technologies for microdisplay printing such as micro characters, the security of the infrared-absorbing printed matter can be further improved.

Industrial Applicability

[0092] The present invention can be used for ID cards such as identity certificates, cards such as credit cards and cash cards, banknotes, etc., but is not limited thereto and can be used in any laminate.

Explanation of Signs

[0093] 1 Laminate (Printed Matter) 2 Portrait (Laser Marking) 3 Personal Identification Information (Laser Marking) 4 Mark (Colored Ink Printing, Fluorescent Ink Printing, or Hologram) 5 Mark (Colored Ink Printing, Fluorescent Ink Printing, or Hologram) 6 Printed Image (Near-Infrared Absorbing Ink Printing) 7 Portrait (Laser Marking) 8 Personal Identification Information (Laser Marking) 9 Base Material Layer (White Sheet) 10 Laser Color-Developing Layer 11, 12 Colored Ink Layer, Fluorescent Ink Layer, or Hologram Layer 13 Near-Infrared Absorbing Ink Layer 14, 15 Overlay Sheet Layer (Transparent Sheet) 16 Part of Printed Image (Near-Infrared Absorbing Ink Printing) 17 Micro Characters Contained in Printed Image (Near-Infrared Absorbing Ink Printing) 18 Micro Characters (Near-Infrared Absorbing Ink Printing) 19 Micro Characters (Near-Infrared Absorbing Ink Printing) 20 Micro Characters (Laser Marking) 21 Mark (Near-Infrared Absorbing Ink Printing) 22 Portrait (Laser Marking) 23 Base Material Intermediate Layer (Second Part) 24 Base Material Intermediate Layer (First Part) 25 First Base Material Layer (White Sheet) 26 Second Base Material Layer (White Sheet) 27 Lenticular Lens 28 Portrait (Laser Marking) 29 Personal Identification Information (Laser Marking) 30 Mark (Colored Ink Printing, Fluorescent Ink Printing, or Hologram) 31 Lenticular Lens 32 Printed Image (Near-Infrared Absorbing Ink Printing) 33 Portrait (Laser Marking) 34 Personal Identification Information (Laser Marking) 35 Clear Window (Transparent Resin) 36, 37 Portrait (Colored Ink Printing, Fluorescent Ink Printing, or Hologram) 38, 39, 40 Sheet 41, 42 Portrait (India Ink Printing, etc., Visible Light and Near-Infrared Absorbing) 43 Portrait (Laser Marking) 44 India Ink Layer 45 Laser Marker Device 46 Control Unit 47 Memory Unit 48 Drive (Scanning) Unit 49 Laser Irradiation Unit 100 Booklet IM1 Printing Unit (Laser Marking) IM2 Printing Unit (Laser Marking)

Claims

1. A laminate comprising: a base material layer; a near-infrared absorption layer containing a near-infrared absorbing ink composition containing a near-infrared absorbing material, formed on the side of the first surface of the base material layer; a laser coloring layer containing a laser coloring agent and coloring when irradiated with laser light, formed on the side of the second surface of the base material layer; a first surface side transmission layer having visible light transmissivity and near-infrared transmissivity, formed on the side of the first surface of the base material layer and being the outermost layer on the side of the first surface in the laminate; and the near-infrared absorbing material contains cesium tungstate or lanthanum hexaboride, and by applying laser light to a target portion of the near-infrared absorption layer, the near-infrared absorbability of the target portion in at least a predetermined wavelength range is reduced; a plurality of convex optical element portions are formed in an area of the surface of the first surface side transmission layer opposite to the near-infrared absorption layer and at least partially overlapping the near-infrared absorption layer. characterized in that it is a laminate.

2. a base material layer; a near-infrared absorption layer containing a near-infrared absorbing ink composition containing a near-infrared absorbing material, formed on the side of the first surface of the base material layer; a laser coloring layer containing a laser coloring agent and coloring when irradiated with laser light, formed on the side of the second surface of the base material layer; and the near-infrared absorbing material contains cesium tungstate or lanthanum hexaboride, and by applying laser light to a target portion of the near-infrared absorption layer, the near-infrared absorbability of the target portion in at least a predetermined wavelength range is reduced; further comprising a window portion having visible light transmissivity and near-infrared transmissivity, formed so as to penetrate the base material layer and the laser coloring layer and at least partially overlap the near-infrared absorption layer. characterized in that it is a laminate.

3. The laminate according to claim 1 or 2, further comprising a first surface side printing layer containing a near-infrared transmissive colored ink composition or a fluorescent ink composition, formed on the side of the first surface of the base material layer.

4. The laminate according to any one of claims 1 to 3, further comprising a first surface side hologram layer having near-infrared transmissivity, formed on the side of the first surface of the base material layer.

5. The laminate according to any one of claims 1 to 4, further comprising a second surface side printing layer containing a colored ink composition or a fluorescent ink composition, formed on the side of the second surface of the base material layer so as to overlap the laser color developing layer.

6. The laminate according to any one of claims 1 to 5, further comprising a second surface side hologram layer formed on the side of the second surface of the base material layer so as to overlap the laser color developing layer.

7. The laminate according to any one of claims 1 to 6, further comprising a second surface side transmissive layer having visible light transmissivity and near-infrared transmissivity, formed on the side of the second surface of the base material layer and being the outermost layer on the side of the second surface in the laminate.

8. The laminate according to claim 7, wherein a plurality of convex optical element portions are formed in a part of the region on the surface of the second surface side transmissive layer opposite to the laser color developing layer.

9. Further comprising a base material intermediate layer, the base material intermediate layer including a first portion and a second portion, The base material layer includes a first base material layer and a second base material layer, the first portion of the base material intermediate layer is located between the first base material layer and the second base material layer, The second portion of the base material intermediate layer is located at an end of the base material intermediate layer and is not located between the first base material layer and the second base material layer, The laminate according to any one of claims 1 to 8.

10. The near-infrared absorption layer includes a near-infrared information display section that displays information based on a change in near-infrared absorption characteristics within the near-infrared absorption layer caused by applying laser light. The laser color-developing layer includes a visible information display section that displays information based on a change in visible light absorption characteristics within the laser color-developing layer caused by applying laser light. The information displayed by the near-infrared information display section and the information displayed by the visible information display section include the same information. The laminate according to any one of claims 1 to 9.

11. A booklet formed by binding a plurality of sheets, wherein at least one of the plurality of sheets is the laminate according to claim 9, and the laminate is bound with other sheets at the second portion of the base material intermediate layer.

12. A base material layer, A near-infrared absorption layer including a near-infrared absorbing ink composition containing a near-infrared absorbing material, formed on the side of the first surface of the base material layer. A laser color-developing layer containing a laser color-developing agent and developing color when laser light is applied, formed on the side of the first surface of the base material layer. A window portion having visible light transmissibility and near-infrared light transmissibility, formed so as to penetrate the base material layer and the laser color-developing layer and overlap at least partially with the near-infrared absorption layer. provided with The near-infrared absorbing material contains cesium tungsten oxide or lanthanum hexaboride, and by applying laser light to a target portion of the near-infrared absorption layer, the near-infrared absorbency of the target portion in at least a predetermined wavelength range is reduced. A laminate.

13. The near-infrared absorption layer includes a near-infrared information display section that displays information based on a change in near-infrared absorption characteristics within the near-infrared absorption layer caused by applying laser light. The laser color - forming layer includes a visible information display unit that displays information based on a change in visible - light absorption characteristics in the laser color - forming layer caused by applying laser light. The information displayed by the near - infrared information display unit and the information displayed by the visible information display unit include the same information. The laminate according to claim 12.

14. A base material layer, A near - infrared absorption layer including a near - infrared absorption ink composition containing a near - infrared absorbing material formed on the side of the first surface of the base material layer, the near - infrared absorbing material including cesium tungsten oxide or lanthanum hexaboride, and including a near - infrared information display unit that displays information based on a change in near - infrared absorption characteristics in the near - infrared absorption layer. A laser color - forming layer containing a laser color - former and that develops color when laser light is applied, formed on the side of the first surface of the base material layer, and including a visible information display unit that displays information based on a change in visible - light absorption characteristics in the laser color - forming layer. A window portion having visible - light permeability and near - infrared light permeability, formed so as to penetrate the base material layer and the laser color - forming layer and at least partially overlap the near - infrared absorption layer. A method for authenticating the laminate, characterized by comparing the display content of the near - infrared information display unit and the display content of the visible information display unit of the laminate.

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