Card and authenticity determination method of card

Abstract

To provide a card having a micropattern arranged visibly on the card surface, which does not impair the design of the card and has security.SOLUTION: Provided is a card in which a picture layer 40, a concealment layer 30, and a core layer 10 are laminated in this order, with a removal section 60 formed that penetrates the picture layer and the concealment layer. A micropattern 50 is formed on the surface of the core layer facing the concealment layer, and part of the micropattern is visible through the removal section, so that authenticity can be determined by visually inspecting the removal section and confirming the presence or absence of the micropattern.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a card having security features. [Background technology]

[0002] Conventionally, a commonly used card is known that includes a transparent layer laminated below a print layer and an intermediate layer laminated below the transparent layer, and by laser processing a laser-processed area of ​​the transparent layer so that the transparent layer remains, the color of the upper surface of the intermediate layer can be seen through the transparent layer from the laser-processed area (see, for example, Patent Document 1). Patent Document 1 describes that it is possible to provide a highly wear-resistant, low-cost card on which characters and other displays can be processed.

[0003] Furthermore, cards with improved security, such as those with micropatterns such as microcharacters on the face of the card to prevent counterfeiting, are also widely known. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-73031 Summary of the Invention [Problem to be solved by the invention]

[0005] However, placing a micropattern on the face of a card can interfere with the design of the card image, meaning that a separate area must be secured on the face of the card for the micropattern to be placed thereon.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a card in which a micropattern is visibly arranged on the card surface, without compromising the design of the card and while still providing security. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the card of the present invention is a card in which a picture layer, a concealing layer, and a core layer are laminated in this order, and a removal section is formed that penetrates the picture layer and the concealing layer, and a micropattern is formed on the surface of the core layer facing the concealing layer, so that a portion of the micropattern is visible through the removal section.

[0008] As a result, the micropattern is visible only in the area where the image layer and concealing layer have been removed, eliminating the need to reserve a separate area on the face of the card for the micropattern.Furthermore, because the micropattern is formed on the face of the card, counterfeiting can be prevented. [Effects of the Invention]

[0009] The card of the present invention does not require a separate area on the card face for placing a micropattern, so the card design is not compromised.In addition, it is possible to prevent counterfeiting, providing security. [Brief explanation of the drawings]

[0010] [Figure 1] Enlarged cross-sectional view illustrating each layer of the card 1. [Figure 2] Plan view showing the appearance of Card 1 [Figure 3] A comparison diagram of the appearance to explain how to determine authenticity based on the presence or absence of microtext. [Figure 4] Functional block diagram of the image acquisition device 100 and the terminal 200 [Figure 5] A comparison diagram of the appearance of a card 1 on which microtext is formed to explain how to determine its authenticity. [Figure 6] An external comparison diagram for explaining a method for determining the authenticity of a card 1 on which lines are formed. [Figure 7] Functional block diagram of the image acquisition device 100 and the authenticity determination device 300 [Figure 8] Flowchart for authenticity determination by authenticity determination device 300 DETAILED DESCRIPTION OF THE INVENTION

[0011] A card according to one embodiment of the present invention will be described with reference to the drawings. Fig. 1 is an enlarged cross-sectional view illustrating each layer of card 1, Fig. 2 is a plan view showing the appearance of card 1, Fig. 3 is a comparative view illustrating a method for determining the authenticity of card 1 having microcharacters formed thereon, Fig. 4 is a comparative view illustrating a method for determining the authenticity of card 1 having continuous lines formed thereon, Fig. 5 is a comparative view illustrating a method for determining the authenticity of card 1 having microcharacters formed thereon, Fig. 6 is a comparative view illustrating a method for determining the authenticity of card 1 having lines formed thereon, Fig. 7 is a functional block diagram of image acquisition device 100 and authenticity determination device 300, and Fig. 8 is a flowchart illustrating authenticity determination using authenticity determination device 300.

[0012] 1, a card 1 according to one embodiment of the present invention is formed by laminating an over-sheet layer 21, a core layer 11, a core layer 10, an over-sheet layer 20, a concealing layer 30, and a design layer 40 in this order. As will be described in detail later, a micropattern 50 is formed on the surface of the core layer 10 facing the concealing layer 30. A removed portion 60 is formed by removing the design layer 40 and the concealing layer 30 so that a portion of the micropattern 50 is visible.

[0013] In the following description of the embodiments and drawings, the side of the design layer 40 will be referred to as the "top" and the side of the core layer 10 as the "bottom" in the stacking direction of the card 1. In addition, in each drawing, the thickness and configuration of each constituent layer are appropriately exaggerated in size for clarity.

[0014] Although each layer will be described, these are not limited to those described, and each layer may be formed of only one layer or two or more layers. Furthermore, the layer configuration can be modified within the scope of the present invention, such as by providing a transparent layer between each layer or by providing an adhesive layer to bond each layer.

[0015] The core layers 10 and 11 are also referred to as card substrates. A wide variety of white or colored plastic sheets can be used as the core layers, including the following single films or composite films: polyethylene terephthalate (PET), PET-G (terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer), polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polycarbonate, polyamide, polyimide, cellulose diacetate, cellulose triacetate, polystyrene, ABS, polyacrylic ester, polypropylene, polyethylene, polyurethane, etc. The thickness of the core layer 10 can be appropriately selected taking into account the overall thickness of the card, and can be, for example, approximately 0.05 mm or more and 0.45 mm or less. In this embodiment, two core layers are provided.

[0016] The over-sheet layer 20 is also referred to as a surface layer or a transparent layer. The over-sheet layer 20 is typically made of the same material as the core layer, but is typically a transparent material with a thickness of approximately 0.05 mm to 0.18 mm. While the card 1 of this embodiment is described as having an over-sheet layer 20, the present invention can be implemented even if the over-sheet layer 20 is not provided. In this embodiment, two over-sheet layers are provided on the outer side of the two core layers in the thickness direction. The over-sheet layer 21 can also be made of the same material as the over-sheet layer 20.

[0017] The material of the over-sheet layer 20 may be any material that is adhesive when heated. However, even if the over-sheet layer 20 itself is not adhesive when heated, the core layer 10 and the over-sheet layer 20 can be integrated by additionally forming a known transparent adhesive layer that generates adhesive force when heated between them. Although not shown, a magnetic stripe may be pre-embedded on the top surface of the over-sheet layer 20 by thermal transfer or the like. This allows data on the magnetic stripe to be read by a magnetic reader or the like. Although not shown, a magnetic stripe may be pre-embedded or pre-embedded on either the front or back surface of the over-sheet layer 21, similar to the over-sheet layer 20.

[0018] The concealing layer 30 is provided, for example, to prevent the card face design from being restricted by the color of the magnetic stripe as described above, or to impart a glossy appearance to the card. The concealing layer 30 contains a resin component and a pigment containing, for example, metal particles.

[0019] The concealing layer 30 is formed by, for example, forming a paste of metallic aluminum (metallic aluminum) powder, which is metal particles with an average particle diameter of approximately 4 μm or more and 12 μm or less, and dissolving this in a vehicle, i.e., a binder, to form an ink for silkscreen printing, and then printing, applying, or the like. Because the metal particles themselves are silver in color, the concealing layer 30 appears to have a lustrous silver color. Alternatively, a black ink with strong concealing properties may be used, in which case the black ink may be, for example, an ink containing carbon black.

[0020] Various resins can be used as binders for forming the concealing layer 30 using ink, such as vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-vinyl alcohol copolymers, vinyl chloride-vinyl acetate-maleic acid copolymers, cellulose-based resins, acrylic resins, vinyl chloride-acrylate copolymers, and bisphenol A epoxy resins. A relatively thick concealing layer 30 can be formed by silkscreen printing using a predetermined screen mesh, using an ink in which a metal resin is dissolved in a binder. The thickness of the concealing layer 30 can be set as desired, but is typically between 1 μm and 5 μm, with a thickness of between 2 μm and 3 μm being preferred.

[0021] As described above, the concealing layer 30 in this embodiment contains fine metal particles. Therefore, the metal particles are likely to generate heat during laser irradiation, which will be described later, and can facilitate removal of the irradiated portion.

[0022] The picture layer 40 is a layer provided on the outermost surface of the card 1. Therefore, the design, characters, etc. formed on the picture layer 40 determine the appearance of the card 1. A design such as the name or logo of the card 1, i.e., a picture 41 common to each card regardless of the owner of the card 1, is formed on the picture layer 40 by a printing method such as offset printing, screen printing, flexographic printing, or gravure printing. In addition, a removal portion 60 is formed on the picture layer 40 to display an information code 42 indicating, for example, a card number or a name, the method of which will be described later.

[0023] The information code 42 is visible through the removed portion 60 that penetrates the design layer 40 and the concealing layer 30. Specifically, by removing the design layer 40 and the concealing layer 30, the core layer 10 becomes visible through the oversheet layer 20 at the removed portion 60. Therefore, the color contrast between the design layer 40 and the core layer 10 makes the information code 42 visible. The shape of the removed portion 60 that displays the information code 42 is preferably a code that indicates essential information for the card 1, such as a card number or name that allows the card 1 to be distinguished from other cards, but it may also be a meaningless graphic. If the removed portion 60 is visible as a display of the information code 42, there is no need to add extra design or text to the design layer 40, and the aesthetic appearance of the card 1 is not impaired.

[0024] The micropattern 50 is formed on the upper surface of the core layer 10. The area in which it is formed may be the entire surface of the core layer 10 or may be a partial area. As will be described in detail later, the micropattern 50 is formed so that a portion of it is visible through the area in which the information code 42 is formed.

[0025] The micropattern 50 is formed by, for example, micro-characters or other minute characters, lines, designs, etc. Because the display is so minute, it cannot be clearly reproduced even if it is copied, and is generally used as an anti-counterfeiting technology. The ink used to form the micropattern 50 is ink made of components that do not contain metal or carbon and are not reactive to lasers.

[0026] Furthermore, it is preferable that the color difference between the micropattern 50 and the background portion of the micropattern 50 of the core layer 10 is ΔE=20 or more. The color difference can be calculated using a spectrophotometer (SD5000 manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS Z8730:2009.

[0027] Note that the above configurations only show the minimum components required to realize this embodiment, and as long as these elements are included, the card may be applied to a contact IC card, a contactless IC card, a dual interface card, etc., depending on the functionality required of the card.

[0028] The appearance of the card 1 of this embodiment having the above-described configuration will now be described. As shown in FIG. 2, when the card is viewed from above in FIG. 1, the image 41 of the image layer 40 and the information code 42 formed by the removal section 60 are visible. In this embodiment, the image 41 corresponds to the logo "DNP Bank." The information code 42 corresponds to the name "DNP TAROU."

[0029] When the inside of the characters "DNP TAROU" is viewed with the naked eye, the details are not visible, but the micropattern 50 formed to a size large enough to make its presence recognizable is visible. In this embodiment, the case where the micropattern 50 is formed as microcharacters is exemplified.

[0030] The card 1 of this embodiment having the configuration described above is manufactured by the following process. First, the oversheet layer 21, core layer 11, core layer 10, oversheet layer 20, concealing layer 30, and design layer 40 are heat-pressed together to be bonded together. The design layer 40 is formed by a printing method such as offset printing, screen printing, flexographic printing, or gravure printing. Before each layer is heat-pressed, a micropattern 50 is printed in advance on the core layer 10. In other words, at this stage, the micropattern 50 is embedded inside the card 1. In this embodiment, the micropattern 50 is formed from fine characters (including numbers and symbols).

[0031] Next, a laser is irradiated from above onto the card-shaped product in which the micropattern 50 is embedded and the layers are pressed together. At this time, the design layer 40 and the concealing layer 30 are burned away to form the information code 42, and the burned-away areas, i.e., the removed areas 60, are visible as indicating the information code 42. As described above, the ink used to form the micropattern 50 is laser-resistant, so even when the laser is irradiated onto the area, it remains unreactive.

[0032] As mentioned above, when the laser is applied, the concealing layer 30, particularly the metal particles therein, generates heat. This heats the relevant portion of the concealing layer 30 and the picture layer 40 located on top of it, making both of them easier to separate from the card 1.

[0033] In this case, the over-sheet layer 20 below the concealing layer 30 is a transparent layer that allows the laser light to pass through and blocks the heat generated by the laser irradiation. This makes it difficult for heat to be transmitted to the core layer 10 below the over-sheet layer 20 and the micropattern 50 formed on the core layer 10, allowing the pattern layer 40 and the concealing layer 30 to be separated without damaging either of them.

[0034] Furthermore, when removing the picture layer 40 and the concealing layer 30 by laser irradiation, processing conditions such as laser output and processing time are adjusted so that both layers are completely removed. At this time, the range of adjustment can be widened by changing the thickness of the oversheet layer 20, and in this respect, it is also preferable to provide the oversheet layer 20 on the card 1. Although it is preferable that the card 1 includes the oversheet layer 20, the present invention can be implemented even without the oversheet layer 20 by appropriately adjusting the processing conditions.

[0035] Next, a method for determining whether the card 1 is authentic or counterfeit will be described using the micropattern 50. As the authenticity determination method, a method performed by a user visually and a method using a determination device will be described.

[0036] With reference to FIG. 3, a method for visually determining authenticity by a user will be described. FIG. 3(a) shows a genuine card on which a micropattern 50 is formed, while FIG. 3(b) shows an unauthorized card on which the micropattern 50 is not formed. This determination method determines authenticity based on whether or not the micropattern 50 is present in the removal unit 60. As shown in FIG. 3(a), the micropattern 50 is formed to such an extent that its presence can be recognized by looking at the card 1 with the naked eye, as described above. Therefore, if the micropattern 50 is not visible on a card 1 on which the micropattern 50 should be visible, as shown in FIG. 3(b), the user can visually determine that the card is not an authorized card.

[0037] Next, we will explain a method for determining authenticity using a terminal owned by a user for a card 1 that has a micropattern 50 formed thereon and cannot be determined to be authentic with the naked eye. As shown in Fig. 4, this determination method comprises an image acquisition device 100 for the card 1 that includes an imaging unit 110 that photographs the card 1 and acquires legitimate photographed image data, a storage unit 120 that stores the acquired legitimate photographed image data, and a communication unit 130 that transmits the legitimate photographed image data to the outside. Also, a terminal 200 of the owner of the card 1 includes a terminal-side communication unit 210 that receives the legitimate photographed image data, and a display unit 220 that displays the legitimate photographed image data.

[0038] The photographing unit 110 is, for example, a digital camera, and photographs the card surface, which is the appearance of the card 1, as image information.

[0039] The storage unit 120 is realized by, for example, a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, or a storage device such as a hard disk or an optical disk.

[0040] The communication unit 130 is realized by, for example, a network interface card (NIC) or a network interface controller. The communication unit 130 is connected to a network N (e.g., the Internet) by wire or wirelessly, and transmits and receives information between the image acquisition device and the authenticity determination device via the network N. For example, the communication unit 130 may transmit and receive information using any communication standard or communication technology, such as Wi-Fi (registered trademark), Bluetooth, a subscriber identity module (SIM), or low power wide area (LPWA).

[0041] The terminal 200 may be, for example, a smartphone or the like, which includes a terminal communication unit 210 and a display unit 220.

[0042] In this authenticity determination method, the photographing unit 110 acquires in advance image information of the appearance of the top surface of the card 1 at the time of manufacture, particularly image information of the area around the removal unit 60, as regular photographed image data, and the memory unit 120 stores the photographed image data. Note that in this embodiment, the regular photographed image data is acquired when the card 1 is manufactured, but it may be acquired at any time after the information code 42 is formed on the card 1.

[0043] The stored photographed image data is transmitted to the terminal 200 by the communication unit 130. The photographed image data received by the terminal-side communication unit 210 of the terminal 200 is displayed on the display unit 220, and the user compares the legitimate photographed image data with the appearance of the card 1 in his / her possession to determine whether the card 1 is authentic or not.

[0044] This authenticity determination is performed by focusing on the removed portion 60 of the card 1, that is, the degree of loss of the visible micropattern 50. An example of this method will be described below.

[0045] With reference to Figure 5, a case where a portion of the visible micropattern 50 is missing will be described. As shown in Figure 5(a), the microcharacter "a" constituting part of the micropattern 50 is completely visible at the inner edge 61 of the removed portion of the legitimate photographed image data (the removed portion 60 surrounded by the dashed line in Figure 2). On the other hand, as shown in Figure 5(b), when the user observes the corresponding position on the card 1, it is seen that the microcharacter "a" is missing. In such a case, there is a difference in the degree of missing microcharacters, and the card is clearly different from the card when the legitimate photographed image data was acquired, so the user determines that the card is not a legitimate card.

[0046] In this way, if there is a difference in part of the microcharacter that can be visually confirmed and determined, it is easy to determine the authenticity of card 1. In addition, if the microcharacter "a" that constitutes part of micropattern 50 is completely visible at inner edge 61 of the removal section in the legitimate captured image data, but the microcharacter "a" is not visible at the time of determination, it is easy to determine that the card 1 is not a legitimate card. Conversely, if the microcharacter "a" that constitutes part of micropattern 50 is partially visible at inner edge 61 of the removal section in the legitimate captured image data, but the fully formed microcharacter "a" is visible at the time of determination, it is also easy to determine that the card is not a legitimate card.

[0047] Furthermore, if the height of the micro characters themselves is between 0.2 mm and 0.3 mm, authenticity determination can be performed more easily.

[0048] Furthermore, if the spacing between the micro characters is 0.2 mm or more and 0.6 mm or less, authenticity determination can be performed more easily.

[0049] Furthermore, if the color difference between the micro characters and the core layer at the back of the characters is ΔE=20 or more, authenticity can be determined more easily.

[0050] The above has described the micropattern 50 as microcharacters, but as another embodiment, a case where the micropattern 50 is parallel lines will be described.

[0051] As shown in FIG. 6 , in the inner edge 62 of the removed portion of the legitimate photographed image data (the removed portion 60 surrounded by the two-dot chain line in FIG. 2 ), multiple lines are formed as a micropattern 50, slanted and parallel to one another. Focusing on a specific line 51 among the multiple lines, this line 51 is interrupted according to the shape of the removed portion 60. However, when a user observes this position, it is visually recognized that the line 51 is interrupted at a clearly different position, as shown in the inner edge 63 of the removed portion in FIGS. 6( a ) and 6 ( b ) (the removed portion 60 surrounded by the dotted line in FIG. 6 ). In other words, the length of the missing portion of the line 51 is different. In such a case, since the degree of loss in the micropattern 50 differs, the card is clearly different from the card used to obtain the legitimate photographed image data, and the user determines that the card is not a legitimate card. Another method for making this determination is to visually compare two or more lines.

[0052] If the line width of the lines is 0.1 mm or more, authenticity can be determined more easily.

[0053] Furthermore, if the spacing between the lines in the parallel lines is 0.3 mm or more and 0.5 mm or less, authenticity determination can be performed more easily.

[0054] Furthermore, if the inclination of the lines in the parallel lines is between 25 degrees and 65 degrees with the longitudinal direction of the card 1 horizontal, authenticity can be determined more easily.

[0055] Next, an authenticity determination method using image processing technology will be described. As shown in Fig. 7, this determination method comprises an image acquisition device 100 for a card 1, which is equipped with an imaging unit 110, a storage unit 120, and a communication unit 130. The configuration of the image acquisition device 100 is the same as that described above, and will be described using the same reference numerals. Also, an authenticity determination device 300 for a card 1 comprises a determination device-side communication unit 310 that receives captured image data, a determination device-side imaging unit 320 that photographs the card 1, and a determination unit 330 that compares two or more sets of captured image data to determine the authenticity of the card 1.

[0056] The authenticity determination device 300 may be, for example, a smartphone or a card reader installed in each store.

[0057] The determination unit 330 is realized by, for example, a central processing unit (CPU), a micro processing unit (MPU), a graphics processing unit (GPU), or the like executing a program stored inside the image acquisition device 100 using a random access memory (RAM) or the like as a working area. The determination unit 330 is also a controller, and is realized by, for example, an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0058] 8, the series of processes of this authenticity determination method will be illustrated. The photographing unit 110 acquires image information of the appearance of the top surface of the card 1 at the time of manufacture, particularly image information of the area near the removal unit 60, as regular photographed image data (S101). The storage unit 120 stores the photographed image data (S102). Next, the determination device photographing unit 320 acquires image information at a similar position as the regular photographed image data at a timing different from that at which the regular photographed image data was acquired, as photographed image data for determination (S301). The communication unit 130 transmits the regular photographed image data to the authenticity determination device 300 (S103), and the determination device communication unit 310 receives the data from the communication unit 130 (S302). Thereafter, the determination unit 330 compares the received regular photographed image data with the acquired photographed image data for determination to determine the authenticity of the card 1 (S303). The timing of sending the regular captured image data from the image acquisition device 100 to the authenticity determination device 300 is not limited to the above flow, and for example, the data may be transmitted and received at a timing before the image is captured by the determination device side image capture unit 320. In this case, the authenticity determination device 300 side is provided with a storage unit (not shown).

[0059] As an example of the determination process, the determination unit 330 identifies the area of ​​the removed portion 60 in both captured image data. The determination unit 330 determines whether the card 1 is genuine or not based on the degree of match of the pixel values, etc., of the image information of the micropattern 50 formed in each of the areas. The determination unit 330 determines that the card 1 is genuine if the degree of match is equal to or greater than a predetermined degree, and determines that the card 1 is fake if the degree of match is less than a predetermined degree.

[0060] The micropattern 50 described in each embodiment is formed of micro characters or lines, but it can also be formed of other patterns or designs.

[0061] Thus, according to the card 1 of this embodiment, the pattern layer 40, the concealment layer 30, and the core layer 10 are laminated in this order, and a removal section 60 is formed that penetrates the pattern layer 40 and the concealment layer 30. A micropattern 50 is formed on the surface of the core layer 10 facing the concealment layer 30, and a portion of the micropattern 50 is visible through the removal section 60, so that a portion of the micropattern 50 is visible only through the removal section 60.

[0062] This eliminates the need to reserve a separate area on the card face for placing the micropattern 50, and does not impair the design of the card. Also, the presence or absence of the micropattern 50 can prevent counterfeiting, providing security.

[0063] In addition, in a card 1 in which a pattern layer 40, a concealing layer 30, and a core layer 10 are stacked in this order, a removal section 60 is formed that penetrates the pattern layer 40 and the concealing layer 30, and a micropattern 50 is formed on the surface of the core layer 10 facing the concealing layer 30, and a portion of the micropattern 50 is visible through the removal section 60, the method determines the authenticity of the card 1 itself based on the shape of the visible micropattern 50, in which the visible micropattern 50 is acquired and stored in a storage device in advance as regular photographed image data, and the authenticity of the card itself is determined by comparing the visible micropattern 50 in the regular photographed image data with the visible micropattern 50 acquired or observed at a time different from when the regular photographed image data was acquired, thereby making it possible to determine the authenticity of the card 1.

[0064] Furthermore, the authenticity of the card 1 can be determined more easily because the authenticity can be determined visually by comparing defects in the micropattern 50 in the visible shape of the micropattern 50.

[0065] Furthermore, the above-described authenticity determination can be performed more accurately because, in addition to the user visually determining whether the card 1 is authentic, a means for determining whether the card 1 is authentic is provided by an authenticity determination device. [Explanation of symbols]

[0066] 1: card, 10, 11: core layer, 20, 21: oversheet layer, 30: concealing layer, 40: design layer, 41: design, 42: information code, 50: micropattern, 60: removal section, 61, 62, 63: inner edge of removal section, 100: image acquisition device, 200: terminal, 300: authenticity determination device

Claims

1. A card having a design layer, a concealing layer, and a core layer laminated in this order, and having a removal portion penetrating the design layer and the concealing layer, a micropattern is formed on the surface of the core layer facing the concealing layer, and a part of the micropattern is visible through the removed portion; card.

2. The removed portion is visible as displaying an information code. The card of claim 1.

3. The micropattern includes any one of micro characters, lines, patterns, and designs.

3. The card of claim 2.

4. The height of the micro characters is 0.2 mm or more and 0.3 mm or less.

4. The card of claim 3.

5. The spacing between the micro characters is 0.2 mm or more and 0.6 mm or less.

4. The card of claim 3.

6. The spacing between the lines is 0.3 mm or more and 0.5 mm or less.

4. The card of claim 3.

7. The line width of the lines is 0.1 mm or more.

4. The card of claim 3.

8. The color difference between the micropattern and the background portion of the micropattern in the core layer is ΔE=20 or more.

3. The card of claim 2.

9. A transparent layer is provided between the hiding layer and the micropattern. A card according to any one of claims 1 to 8.

10. a pattern layer, a concealing layer, and a core layer are laminated in this order, and a removed portion is formed that penetrates the pattern layer and the concealing layer; A card in which a micropattern is formed on a surface of the core layer facing the concealing layer, and a part of the micropattern is visible through the removed portion, A method for determining whether a card is authentic or counterfeit based on the shape of a visible micropattern, comprising: The visible micropattern is acquired and stored in advance in a storage device as regular photographed image data, The authenticity of the card is determined by comparing the visible micropattern in the regular photographed image data with the visible micropattern acquired or observed at a timing different from that at which the regular photographed image data was acquired. Authenticity determination method.

11. The authenticity determination is performed by using a visible micropattern. By comparing the degree of defects in the micropattern, it is possible to visually determine authenticity. The authenticity determination method according to claim 10.

Images