Printed matter and verification method and verification system of same

Abstract

To provide a printed matter whose authenticity can be determined easily and at low cost, and a verification method and verification system for determining the authenticity thereof.SOLUTION: A printed matter according to an embodiment includes a substrate, a first color layer disposed on the substrate, and a second color layer disposed on the substrate. When illuminated with light from outside, a latent image is formed on the substrate, which is visualized in color by at least a first color emitted from the first color layer and a second color emitted from the second color layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to printed matter on which personal information is printed, such as a passport or an ID card, and to a method and system for verifying the same. [Background technology]

[0002] 2. Description of the Related Art Printed materials on which personal information is printed, such as passports and ID cards, are required to be difficult to forge or alter.

[0003] To meet this demand, printing has conventionally been carried out using inks containing special pigments such as fluorescent pigments, i.e., so-called special inks. If a thermal transfer recording method using a thermal printhead is used for this printing, it is possible to easily record information that differs for each item, such as personal information (see, for example, Patent Documents 1 and 2).

[0004] Furthermore, by adding a thermal transfer recording method using fluorescent ink that emits red, blue, and green light as a special ink, it is possible to make counterfeiting or alteration even more difficult by comparing the color image for authentication with the fluorescent color image made from the fluorescent ink (see Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-240136 [Patent Document 2] Japanese Patent Application Publication No. 10-35089 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-225774 [Patent Document 4] Japanese Patent Application Laid-Open No. 2023-69349 Summary of the Invention [Problem to be solved by the invention]

[0006] However, such conventional printed matter has the following problems.

[0007] For example, to determine the authenticity of printed matter that must be difficult to counterfeit or alter, there is a method in which a latent image that is illuminated with ultraviolet light and made to fluoresce is compared with a visible image for verification. However, this method requires the use of ultraviolet light, or a so-called black light. Therefore, this method has the problem of being difficult to adopt.

[0008] Furthermore, if the visible image for verification is expressed in yellow, blue, and red, it is desirable that the fluorescent image for comparison and verification also be expressed in RGB fluorescent color. However, in this case, three colors of fluorescent ink are required, which is expensive.

[0009] The present invention has been made in view of the above circumstances, and aims to provide a printed matter that can be easily and inexpensively authenticated, and a verification method and verification system for authenticating the printed matter. [Means for solving the problem]

[0010] In order to achieve the above object, a first aspect of the present invention is a printed matter comprising a substrate, a first color layer disposed on the substrate, and a second color layer disposed on the substrate, and when illuminated with light from outside, a latent image is formed on the substrate, which is visualized in color by at least a first color emitted from the first color layer and a second color emitted from the second color layer.

[0011] A second aspect of the present invention is the printed matter of the first aspect, in which the color of the substrate is white, the light illuminated from outside is light of a third color, the first color layer emits the first color when illuminated with light of the third color from outside, the second color layer emits the second color when illuminated with light of the third color from outside, the first color, the second color, and the third color are all neither white nor black, but are different colors from one another, and in parts of the substrate where neither the first color layer nor the second color layer is located, when light of the third color is illuminated from outside, the light of the third color is reflected, and the latent image is visualized in color by the first color, the second color, and the third color.

[0012] A third aspect of the present invention is the printed matter of the second aspect, wherein the third color light is blue light, the first color layer is a red fluorescent layer that emits red as the first color when illuminated with blue light from outside, and the second color layer is a green fluorescent layer that emits green as the second color when illuminated with blue light from outside.

[0013] A fourth aspect of the present invention is the printed matter of the second aspect, further comprising a color absorbing layer disposed on the substrate, wherein when illuminated with light of a third color from the outside, the color absorbing layer absorbs the light of the third color and appears black, and the latent image is visualized in color by the first color, the second color, the third color, and black.

[0014] A fifth aspect of the present invention is the printed matter of the fourth aspect, in which the third color light is blue light, the first color layer is a red fluorescent layer that emits red as a first color when illuminated with blue light from outside, the second color layer is a green fluorescent layer that emits green as a second color when illuminated with blue light from outside, and the color absorption layer is a yellow layer made of a color that is complementary to the blue light.

[0015] A sixth aspect of the present invention is the printed matter of the fifth aspect, wherein the color absorbing layer includes a first color absorbing layer that is a yellow layer and a second color absorbing layer that is a blue absorbing layer that absorbs blue light.

[0016] A seventh aspect of the present invention is a verification method for verifying the authenticity of a printed matter of any of the second to sixth aspects, comprising the steps of illuminating the printed matter with light of a third color, comparing the image visualized by the illumination with light of the third color with an authentic image, and determining that the printed matter is authentic if the visualized image and the authentic image match as a result of the comparison, and determining that the printed matter is not authentic if they do not match.

[0017] An eighth aspect of the present invention is a verification method of aspect 7, which is implemented by an information terminal equipped with a white light source that emits white light and an optical filter that extracts light of a third color from the white light emitted from the white light source, and includes a step of obtaining light of the third color illuminated in the illuminating step by passing the white light emitted from the white light source through the optical filter.

[0018] A ninth aspect of the present invention is the verification method according to the eighth aspect, wherein the information terminal is a smartphone, and the white light source is an LED light mounted on the smartphone.

[0019] A tenth aspect of the present invention is a verification system for verifying the authenticity of a printed matter of any of the second to sixth aspects, comprising: a white light source that emits white light; an optical filter that extracts light of a third color from the white light emitted from the white light source; a comparison unit that compares an image visualized by illuminating the printed matter with the third color light with an authentic image; and a judgment unit that determines that the printed matter is authentic if the visualized image and the authentic image match, and determines that the printed matter is not authentic if they do not match.

[0020] An eleventh aspect of the present invention is a verification system of the tenth aspect, further comprising an imaging unit that captures an image visualized by illuminating the printed matter with light of a third color, and a comparison unit that compares the image captured by the imaging unit with an authentic image.

[0021] A twelfth aspect of the present invention is a verification system of the eleventh aspect, which is realized by a smartphone and an optical filter, in which the white light source and the imaging unit are an LED light and a camera provided on the smartphone, and the comparison unit and judgment unit are realized by a program installed on the smartphone. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a printed matter that can be easily and inexpensively authenticated, and a verification method and verification system for authenticating the printed matter. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a plan view showing an example of an authentication card, which is an example of a printed matter according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged side view of a part of the region R indicated by the dotted line in FIG. [Figure 3] FIG. 3 is a partial plan view showing an example of the configuration of the thermal transfer ribbon. [Figure 4] FIG. 4 is a diagram showing the excitation characteristics of the fluorescent panel, the spectral wavelength characteristics of the green fluorescent layer, and the spectral wavelength characteristics of the red fluorescent layer. [Figure 5] Figure 5 shows (a) an external view of an LED light and (b) a diagram of the relative luminance characteristics of the illumination light emitted from the LED light. [Figure 6] FIG. 6 is a diagram illustrating the mechanism by which the second authentication image is visualized and displayed in full color when illuminated by an LED light. [Figure 7] FIG. 7 is a plan view of the authentication card illustrating a state in which the second authentication image is visualized and displayed in full color when illuminated by an LED light. [Figure 8] FIG. 8 is a diagram showing the light absorption characteristics of blue absorbing ink. [Figure 9] FIG. 9 is a partial plan view showing an example of the configuration of a thermal transfer ribbon provided with a fluorescent panel for the blue absorbing layer. [Figure 10] FIG. 10 is a diagram showing a smartphone and an optical filter that realize a verification system according to an embodiment of the present invention. [Figure 11] FIG. 11 is a diagram showing the emission wavelength characteristics of white light emitted from a white LED. [Figure 12] FIG. 12 is a diagram showing a state in which a short-pass filter is superimposed on a white LED. [Figure 13] FIG. 13 is a diagram showing the emission wavelength characteristics of light obtained by cutting the long wavelength side from white light having the emission wavelength characteristics′ shown in FIG. [Figure 14] FIG. 14 is a diagram showing the visualized second authentication image as viewed through the monitor of a smartphone. [Figure 15] FIG. 15 is a flowchart showing the flow of operations of the verification system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc., are not necessarily the same as those in reality. Furthermore, even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In this specification and each drawing, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed and redundant explanations will be omitted as appropriate.

[0025] (Printed material) First, a printed matter according to an embodiment of the present invention will be described.

[0026] In the following, an authentication card will be used as an example of a printed matter according to an embodiment of the present invention, but the printed matter according to an embodiment of the present invention is not limited to an authentication card.

[0027] FIG. 1 is a plan view showing an example of an authentication card, which is an example of a printed matter according to an embodiment of the present invention.

[0028] 1, the authentication card 1 has personal authentication information, including name, address, date of birth, gender, etc., printed on a base material 11, and further has a first authentication image 13, such as a facial photograph, printed in full color. The first authentication image 13 can be visually confirmed.

[0029] The authentication card 1 also has a second authentication image 12 printed on it. The second authentication image 12 can be the same facial photograph as the first authentication image 13. However, the second authentication image 12 is a latent image, making it difficult to visually confirm; only a faint yellowish image is visible.

[0030] FIG. 2 is an enlarged side view of a part of the region R including the second authentication image 12, which is indicated by the dotted line in FIG.

[0031] The second authentication image 12 is formed by providing a red fluorescent layer 41, a green fluorescent layer 42, and a yellow layer 46 on a base substrate 11. The red fluorescent layer 41, the green fluorescent layer 42, and the yellow layer 46 can be realized by, for example, red fluorescent ink, green fluorescent ink, and yellow fluorescent ink transferred by thermal transfer ribbon, respectively.

[0032] FIG. 3 is a partial plan view showing an example of the configuration of the thermal transfer ribbon.

[0033] From the thermal transfer ribbon 4 as illustrated in FIG. 3, the red fluorescent layer 41, the green fluorescent layer 42, and the yellow layer 46 are thermally transferred onto the base substrate 11 by a thermal head.

[0034] The thermal transfer ribbon 4 is constructed by regularly and repeatedly arranging fluorescent panels P (e.g., P1, P2, P3, P4, P5, etc.) on a transparent PET substrate 40 in the longitudinal direction L of the thermal transfer ribbon 4. The length of one fluorescent panel P along the longitudinal direction L corresponds to the horizontal width of one screen of the authentication card 1. This length corresponds to the distance between two adjacent dividing lines 49 shown in FIG. 3.

[0035] A fluorescent panel P can be divided into a portion for a colored layer and a portion for a fluorescent layer. A fluorescent panel divided in this manner is described in Patent Document 4. In the example shown in FIG. 3, the fluorescent panel P1 is divided into a right portion for a colored layer such as a blue layer 44 and a left portion for a fluorescent layer such as a red fluorescent layer 41. The fluorescent panel P2 is divided into a right portion for a colored layer such as a red layer 45 and a left portion for a fluorescent layer such as a green fluorescent layer 42.

[0036] The fluorescent panels P3, P4, and P5 are not divided, and the fluorescent panel P3 is for the yellow layer 46, the fluorescent panel P4 is for the black layer 47, and the fluorescent panel P5 is for the primer layer 48.

[0037] The primer layer 48 is provided to improve adhesion between the printed image and the card when printing by an indirect transfer method, in which an image is printed from the thermal transfer ribbon 4 onto an intermediate transfer medium (not shown) and the intermediate transfer medium with the printed image is then transferred to a card. On the other hand, when printing an image with a direct transfer printer, the primer layer 48 functions as a protective layer.

[0038] Such a thermal transfer ribbon 4 allows the visible first authentication image 13 and the latent second authentication image 12 to be printed simultaneously on the authentication card 1, thereby shortening the printing time.

[0039] FIG. 4 is a graph showing excitation characteristics 30 of fluorescent panel P, green fluorescent emission characteristics 31 showing the spectral wavelength characteristics of green fluorescent layer 42, and red fluorescent emission characteristics 32 showing the spectral wavelength characteristics of red fluorescent layer 41.

[0040] When the second authentication image 12 is illuminated with light of a wavelength that shows a high relative brightness in the excitation characteristic 30, the green fluorescent layer 42 forming the second authentication image 12 emits green light having a brightness peak at approximately 500 nm, as shown in the green fluorescent emission characteristic 31, and the red fluorescent layer 41 forming the second authentication image 12 emits red light having a brightness peak at approximately 610 nm, as shown in the red fluorescent emission characteristic 32.

[0041] An LED light can be used as a light source that emits light of a wavelength (up to about 450 nm) that exhibits high relative brightness in the excitation characteristics 30.

[0042] FIG. 5 is a diagram showing (a) an external view of the LED light 21 and (b) a relative luminance characteristic 22 of illumination light 22' emitted from the LED light 21.

[0043] FIG. 6 is a diagram illustrating the mechanism by which, when illuminated by the LED light 21, the second authentication image 12 is visualized by the illumination light 22' from the LED light 21 and displayed in full color.

[0044] FIG. 7 is a plan view of the authentication card 1 illustrating a state in which, when illuminated by the LED light 21, the second authentication image 12 is visualized by the illumination light 22' from the LED light 21 and displayed in full color.

[0045] The illumination light 22' emitted from the LED light 21 is blue light having a peak brightness at about 450 nm, as exemplified by the relative brightness characteristic 22 shown in FIG. 5(b).

[0046] 6, when the second authentication image 12 is illuminated with such illumination light 22', the green fluorescent layer 42 emits green light 42'' having a relative luminance distribution indicated by the green fluorescent emission characteristic 31, and the red fluorescent layer 41 emits red light 41'' having a relative luminance distribution indicated by the red fluorescent emission characteristic 32. That is, the green fluorescent layer 42 emits green light, and the red fluorescent layer 41 emits red light.

[0047] The red phosphor used in the red phosphor layer 41 is CuAlSiN3:Eu 2+ and M2Si5N8:Eu 2+ (M=Ca, Sr, Ba) is preferable. The green phosphor used in the green fluorescent layer 42 is Ca3Sc2Si3O 12 :Ce 3+ Or, Si6-z Al Z O Z N 8-Z :Eu 2+ (0 < z < 4.2) etc. are desirable. However, these are all examples and not limitations.

[0048] Also, the second authentication image 12 is provided with a yellow layer 46. Since yellow is in a complementary color relationship with blue, the yellow layer 46 absorbs the blue illumination light 22’ and appears black.

[0049] The material of the base substrate 11 is a material having white so that it can reflect blue light. Therefore, when the second authentication image 12 is illuminated with the blue illumination light 22’, in the portion of the base substrate 11 where neither the red fluorescent layer 41, the green fluorescent layer 42, nor the yellow layer 46 is arranged, the illumination light 22’ is reflected and becomes the reflected light 22’’, so this portion appears blue.

[0050] Thus, when the second authentication image 12 is illuminated with the blue illumination light 22’, it can emit green, red, and blue, so RGB representation by light becomes possible. Therefore, when the second authentication image 12 is illuminated with the blue illumination light 22’, as illustrated in FIG. 7, it is visualized in full color. Also, by changing the amount of the yellow layer 46 that appears black, the contrast can be adjusted, so the second authentication image 12 is displayed as a clear full-color image.

[0051] Furthermore, in order to increase the intensity of black even more, in addition to the yellow layer 46, a blue absorption layer that absorbs blue light may be provided in the second authentication image 12. The blue absorption layer can be realized by blue absorption ink.

[0052] FIG. 8 is a diagram showing the light absorption characteristics of the blue absorption ink.

[0053] The blue absorption layer can be composed of blue absorption ink having a light absorption characteristic having an absorption peak at about 450 nm, such as the light absorption characteristic 53 illustrated in FIG. 8.

[0054] FIG. 9 is a partial plan view showing an example of the configuration of a thermal transfer ribbon 4' provided with a fluorescent panel P3' for the blue absorbing layer 43. As shown in FIG.

[0055] The fluorescent panel P3′ is divided into a right portion for the yellow layer 46 and a left portion for the blue absorbing layer 43. Such a fluorescent panel P3′ can be realized by using the left portion of the fluorescent panel P3 illustrated in FIG. 3 as the blue absorbing layer 43.

[0056] Using such a thermal transfer ribbon 4', a blue absorbing layer 43 can be provided on the second authentication image 12. The blue absorbing layer 43 efficiently absorbs the blue illumination light 22', making the second authentication image 12 appear blacker than the yellow layer 46. Therefore, by providing the blue absorbing layer 43, the second authentication image 12 becomes less visible when it is a latent image, but when it is visualized, the black parts are displayed as a clearer full-color image.

[0057] As described above, in the printed matter according to the embodiment of the present invention, the latent second authentication image 12 can be formed by combining the red fluorescent layer 41, the green fluorescent layer 42, the yellow layer 46, and in some cases, also the blue absorbing layer 43.

[0058] The second authentication image 12 is normally difficult to see, but when illuminated with blue light, the red fluorescent layer 41 portion turns red, the green fluorescent layer 42 portion turns green, the yellow layer 46 and blue absorption layer 43 portion turns black, and the other portions, i.e., the portions of the base substrate 11 that do not have the red fluorescent layer 41, green fluorescent layer 42, yellow layer 46, or blue absorption layer 43, turn blue, thereby revealing the image in vivid full color.

[0059] Since the fluorescent ink used for the second authentication image 12 only needs to be two colors, red and green, the printed matter according to the embodiment of the present invention can be produced at low cost.

[0060] (Verification method) Next, a method for verifying a printed matter according to an embodiment of the present invention will be described.

[0061] 1, an authentication card 1, which is an example of a printed matter according to an embodiment of the present invention, has personal authentication information including name, address, date of birth, gender, etc. printed thereon, and further has a first authentication image 13, such as a facial photograph, printed in full color. The first authentication image 13 can be visually confirmed.

[0062] The authentication card 1 also has a second authentication image 12 printed thereon. The second authentication image 12 can be the same facial photograph as the first authentication image 13. Therefore, in the following description, it is assumed that the second authentication image 12 is the same facial photograph as the first authentication image 13. The second authentication image 12 is a latent image, which is difficult to visually confirm; only a faint yellowish image is visible.

[0063] In the method for verifying a printed matter according to the embodiment of the present invention, an LED light 21 that emits blue light is prepared to visualize the latent second authentication image 12.

[0064] As the LED light 21, one that emits blue light having an emission luminance distribution 22 with a luminance peak at approximately 450 nm, as exemplified in Fig. 5(b), is used. Unlike black lights, LED lights 21 that emit such blue light are easily available.

[0065] 7, the second authentication image 12 is illuminated with blue illumination light 22' from the LED light 21. As a result, the latent second authentication image 12 is visualized and displayed in full color.

[0066] The user visually compares the facial photograph of the second authentication image 12 displayed in full color with the facial photograph of the first authentication image 13, and if the two facial photographs match, the user can verify that the authentication card 1 is genuine.

[0067] On the other hand, if the two facial photographs do not match, the user will consider the authentication card 1 to be fraudulent.

[0068] Furthermore, if the second authentication image 12 is visualized but not displayed in full color, the authentication card 1 is deemed to be fraudulent even if the two facial photographs match.

[0069] As described above, according to the method for verifying a printed matter according to the embodiment of the present invention, the LED light 21 that emits blue light can be used to easily verify a printed matter.

[0070] (Verification System) If it is not possible to prepare an LED light 21 that emits blue light, a verification system realized by a smartphone and an optical filter can be used to verify a printed matter according to an embodiment of the present invention, as will be described below. This verification system applies the verification method according to an embodiment of the present invention.

[0071] FIG. 10 is a diagram showing a smartphone and an optical filter that realize a verification system according to an embodiment of the present invention.

[0072] Figure 10(a) is a plan view of the smartphone 7 seen from the front side, Figure 10(b) is a plan view of the smartphone 7 seen from the back side, and Figure 10(c) is a plan view of a short-pass filter 75, which is an example of an optical filter.

[0073] As illustrated in Fig. 10(a), a monitor 71 is provided on the front side of the smartphone 7. As illustrated in Fig. 10(b), a camera 72 and a white LED 73 are provided on the back side of the smartphone 7. The white LED 73 is a white light source that emits white light.

[0074] FIG. 11 is a diagram showing an emission wavelength characteristic 73 ′ of white light emitted from the white LED 73 .

[0075] FIG. 12 is a diagram showing a state in which a short-pass filter 75 is superimposed on a white LED 73. As shown in FIG.

[0076] 11 is realized by simultaneously illuminating blue light emitted from the white LED 73 and yellow light, which is its complementary color, and appears white to the human eye. However, the method for generating white light is not limited to this.

[0077] As illustrated in Figure 12, the short-pass filter 75 is used in combination with the white LED 73 to cut out light from the white light emitted by the white LED 73 that is not required for visualizing the second authentication image 12.

[0078] As is not clear from the excitation characteristics 30 in FIG. 4, light with wavelengths longer than about 450 nm is not required for visualizing the second authentication image 12.

[0079] Therefore, the short-pass filter 75 has a characteristic of cutting off light with wavelengths longer than approximately 450 nm, as shown by the cutoff characteristic 75' in Figure 11. Such a short-pass filter 75 can be fabricated by controlling the multilayer vapor-deposited thin film. It can also be fabricated by combining the transmission and absorption characteristics of multiple dyes.

[0080] Figure 13 shows an emission wavelength characteristic 74 of light in which wavelengths longer than approximately 450 nm are cut from white light having the emission wavelength characteristic 73' shown in Figure 11 by a short-pass filter 75 having the cutoff characteristic 75' shown in Figure 11.

[0081] The emission wavelength characteristic 74 shown in Fig. 13 has a luminance peak at about 450 nm, similar to the relative luminance characteristic 22 shown in Fig. 5. Therefore, the light having the emission wavelength characteristic 74 shown in Fig. 13 is blue light. When the second authentication image 12 is illuminated with this blue light, the second authentication image 12 is visualized according to the mechanism described above and is displayed in full color.

[0082] The user can also view the visualized second authentication image 12 through the monitor 71 of the smartphone 7.

[0083] FIG. 14 is a diagram showing the visualized second authentication image 12 as viewed through the monitor 71 of the smartphone 7. As shown in FIG.

[0084] As illustrated in Figure 14, to view the visualized second authentication image 12 through the monitor 71 of the smartphone 7, the white LED 73 is superimposed on the short-pass filter 75, the white LED 73 is activated, and the second authentication image 12 is illuminated with blue light that has passed through the short-pass filter 75, while the smartphone 7 is set to camera mode and the second authentication image 12 is displayed on the monitor 71.

[0085] In fact, when an SHX450 long wavelength cut filter manufactured by Asahi Spectroscopy Co., Ltd. was superimposed on the white LED 73 part of the smartphone 7 as a short pass filter 75, the smartphone 7 was set to video mode, the white LED 73 was turned on, and the authentication card 1 was viewed from the monitor 71, and it was confirmed that the second authentication image 12 appeared in color and was displayed on the monitor 71.

[0086] With the visualized second authentication image 12 displayed on the monitor 71, the user can capture the visualized second authentication image 12 by pressing the shutter of the camera 72. Also, with the first authentication image 13 displayed on the monitor 71, the user can point the camera 72 at the first authentication image 13 and capture the image of the first authentication image 13 by pressing the shutter of the camera 72.

[0087] Then, the facial photograph in the captured second authentication image 12 is compared with the facial photograph in the first authentication image 13, and depending on whether the two facial photographs match, it can be verified whether the authentication card 1 is genuine or not.

[0088] Such verification can be performed by the user comparing both facial images, but can also be performed automatically by a dedicated app installed on the smartphone 7.

[0089] The dedicated application compares the facial photograph of the second authentication image 12 captured by the camera 72 with the facial photograph of the first authentication image 13. For example, machine learning or image processing can be used for the comparison.

[0090] If the comparison shows that the two facial images match, the dedicated application determines that the authentication card 1 is authentic. On the other hand, if the two facial images do not match, the dedicated application determines that the authentication card 1 is fraudulent. Furthermore, if the second authentication image 12 is not full color, the dedicated application also determines that the authentication card 1 is fraudulent.

[0091] In this way, automatic verification of the authentication card 1 is possible by using a smartphone 7 with a dedicated app installed.

[0092] Next, an example of the operation of the verification system according to the embodiment of the present invention will be described.

[0093] As described above, the verification system according to the embodiment of the present invention is realized by the smartphone 7 and the optical filter 75, and the verification method according to the embodiment of the present invention is applied. In addition, a dedicated application for automatically verifying the authentication card 1 is installed in the smartphone 7.

[0094] FIG. 15 is a flowchart showing the flow of operations of the verification system according to the embodiment of the present invention.

[0095] When the verification system verifies a printed matter, such as an authentication card 1, first, the white LED 73 of the smartphone 7 is turned on with the short-pass filter 75 superimposed on it, and the blue light that has passed through the short-pass filter 75 illuminates the second authentication image 12 (S1). At this time, the smartphone 7 is set to the camera mode.

[0096] When the second authentication image 12 is illuminated with blue light, as illustrated in FIG. 6, green light 42'' is emitted from the green fluorescent layer 42 and red light 41'' is emitted from the red fluorescent layer 41. As a result, the green fluorescent layer 42 appears green and the red fluorescent layer 41 appears red. In addition, the yellow layer 46 and the blue absorbing layer 43 (if applied) absorb blue light and therefore appear black.

[0097] In addition, in the portions of the base substrate 11 where none of the red fluorescent layer 41, the green fluorescent layer 42, the yellow layer 46, and the blue absorbing layer 43 are arranged, the illumination light 22' is reflected and becomes reflected light 22'', so that the portions appear blue.

[0098] In this way, when the second authentication image 12 is illuminated with blue light, it is visualized in full color with green, red, and blue, and is displayed with contrast adjusted by black (S2).

[0099] As described above, the smartphone 7 is set to the camera mode, so that the second authentication image 12 displayed in full color can be confirmed on the monitor 71, as shown in FIG. 14 (S3).

[0100] With the second authentication image 12 displayed on the monitor 71 in this manner, the user presses the shutter of the camera 72 to capture the visualized second authentication image 12. The user also aims the camera 72 at the first authentication image 13, and with the first authentication image 13 displayed on the monitor 71, presses the shutter of the camera 72 to capture the first authentication image 13 (S4).

[0101] Next, the facial photograph of the captured second authentication image 12 is compared with the facial photograph of the first authentication image 13, and depending on whether the two facial photographs match, it is verified whether the authentication card 1 is genuine or not.

[0102] Such verification can be performed visually by the user, but can also be performed by a dedicated app installed on the smartphone 7. The following describes the case where the verification is performed by a dedicated app.

[0103] The dedicated application compares the first authentication image 13 with the second authentication image 12 by, for example, machine learning or image processing (S5).

[0104] If the comparison results in a match between the two facial photographs (S5: Yes), the authentication card 1 is determined to be authentic (S6), and if they do not match (S5: No), the authentication card 1 is determined to be fraudulent (S7).The dedicated application also determines that the authentication card 1 is fraudulent if the second authentication image 12 captured by the camera 72 is not full color.

[0105] In this way, by using the smartphone 7 on which a dedicated application is installed, it is possible to automatically verify the authentication card 1.

[0106] As described above, a verification system to which the verification method according to the embodiment of the present invention is applied can automatically verify the authenticity of printed materials, such as passports and ID cards, that have personal information attached and that have been designed to prevent counterfeiting and tampering. Conventionally, such automatic verification was impossible using UV-excited fluorescence using ultraviolet light (black light), but according to the embodiment of the present invention, it can be easily performed using a general-purpose smartphone.

[0107] Next, we will explain two examples in which an authentication card 1 was actually produced on which the second authentication image 12 was formed as a latent image, and it was confirmed that by illuminating the authentication card 1 with blue light, the second authentication image 12 was visualized and displayed in full color. [Example]

[0108] In Example 1, a transparent PET film with a thickness of 12 μm was used as the support for the thermal transfer ribbon 4. On this support, inks consisting of 5 parts by weight of pigment, 15 parts by weight of binder resin, 40 parts by weight of methyl ethyl ketone, and 40 parts by weight of toluene (hereinafter referred to as "color inks") were applied by gravure printing to a thickness of 1 μm on a fluorescent panel P as shown in FIG. 3 to form a blue layer 44, a red layer 45, a yellow layer 46, and a black layer 47.

[0109] Similarly, red fluorescent layer 41 and green fluorescent layer 42 were applied to a thickness of 1.5 μm on fluorescent panel P as shown in FIG. 3, and an ink consisting of 20 parts by weight of primer resin 48, 40 parts by weight of methyl ethyl ketone, and 40 parts by weight of toluene was applied to the panel by gravure printing to a thickness of 2 μm, thereby producing thermal transfer ribbon 4.

[0110] By repeatedly printing the above combinations, a small roll of ribbon for a thermal transfer printer was produced.

[0111] In both the yellow, red, and blue ink pigments and the green and red luminescent fluorescent pigments excited at 450 nm, Dianale BR-83 manufactured by Mitsubishi Chemical Corporation was used as the binder resin.

[0112] The primer resin used was Vylon 600 manufactured by Toyobo Co., Ltd.

[0113] Furthermore, using the small roll of ribbon mentioned above and a thermal transfer printer with a thermal head, an image like that shown in Authentication Card 1 was printed onto a 0.72 mm thick white PET-G card to produce Authentication Card 1 as shown in Figure 1.

[0114] As shown in Figure 1, the authentication card 1 produced here allows the user to see the photograph of the face and personal information written in ink in the first authentication image 13, and the second authentication image 12 placed in area R is a latent image, and although a faint yellow image is visible under natural light, it is difficult to determine what kind of image it is.

[0115] When such an authentication card 1 was illuminated with an LED light 21 as shown in Figure 7, the second authentication image 12 emitted fluorescence, and the second authentication image 12 became visible and was displayed in full color.

[0116] Furthermore, it was confirmed that it is possible to compare the facial photograph of the second authentication image 12 displayed in full color with the facial photograph of the first authentication image 13 and determine whether the two facial photographs match.

[0117] As described above, in Example 1, it was confirmed that the printed matter according to the embodiment of the present invention can be verified by the verification method according to the embodiment of the present invention. [Example]

[0118] In Example 2, a transparent PET film having a thickness of 12 μm was used as the support for the thermal transfer ribbon, and similarly to Example 1, the inks for the respective color layers were applied to the panel shape by gravure printing.

[0119] However, in Example 2, a thermal transfer ribbon was produced by applying a blue absorbing layer 43 to a portion of the panel of the yellow layer 46 using an ink consisting of 3 parts by weight of blue absorbing pigment, 17 parts by weight of binder resin, 40 parts by weight of methyl ethyl ketone, and 40 parts by weight of toluene by gravure printing in the form of a panel as shown in Figure 9.

[0120] Then, by repeatedly printing the above combinations, a small roll of ribbon for a thermal transfer printer was produced.

[0121] As the blue absorbing dye, FDB-005 manufactured by Yamada Chemical Industry Co., Ltd. was used, and as the binder resin, BR-83 was used.

[0122] Using the small roll ribbon thus produced, an authentication card was produced in the same manner as in Example 1.

[0123] As a result, the second authentication image 12 of the authentication card 1 produced in this Example 2 was printed in a lighter color than the second authentication image 12 of the authentication card 1 produced in Example 1, because the yellow part of the printing on the yellow layer 46 was printed in the blue absorbing layer 43.

[0124] This makes the second authentication image 12 even more difficult to see, and it has been confirmed that this can further enhance the anti-counterfeiting effect.

[0125] Although the best mode for carrying out the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to such a configuration. Those skilled in the art may conceive of various modifications and alterations within the scope of the technical ideas of the invention as defined in the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0126] 1 Authentication Card 4, 4' Thermal Transfer Ribbon 7. Smartphones 11 Base material 12 Second authentication image 13 First authentication image, face photo 21 LED lights 22 Relative luminance characteristics 22' lighting 22'' reflected light 30 Excitation characteristics 31 Green fluorescence emission characteristics 32 Red fluorescence emission characteristics 40 Transparent PET base material 41 Red fluorescent layer 41'' red light 42 Green fluorescent layer 42'' green light 43 Blue absorbing layer 44 Blue layer 45 Red Layer 46 Yellow layer 47 Black Layer 48 Primer layer 49 Divider Line 53 Light absorption characteristics 71 Monitor 72 Camera 73' White light emission wavelength characteristics 74 Emission wavelength characteristics of light with the long wavelength side cut off 75 Optical filters, short-pass filters 75' cutoff characteristics L Longitudinal direction P Fluorescent Panel

Claims

1. A substrate; a first color layer disposed on the substrate; a second color layer disposed on the substrate; A printed matter having a latent image formed on the substrate, the latent image being visualized in color by at least a first color emitted from the first color layer and a second color emitted from the second color layer when illuminated with light from outside.

2. The color of the substrate is white, the externally illuminated light is light of a third color, the first color layer emits the first color when illuminated with the third color light from the outside; the second color layer emits the second color when illuminated with the third color light from the outside; the first color, the second color, and the third color are not all white or black, but are different colors from one another; In a portion of the base material where neither the first color layer nor the second color layer is disposed, when the third color light is illuminated from the outside, the third color light is reflected, The printed matter according to claim 1 , wherein the latent image is visualized in color by the first color, the second color, and the third color.

3. the third color light is blue light; the first color layer is a red fluorescent layer that emits red light as the first color when illuminated with the blue light from the outside, The printed matter according to claim 2 , wherein the second color layer is a green fluorescent layer that emits green as the second color when illuminated with the blue light from the outside.

4. further comprising a color absorbing layer disposed on the substrate; the color absorbing layer, when illuminated with the third color light from the outside, absorbs the third color light and appears black; The printed matter according to claim 2 , wherein the latent image is visualized in color by the first color, the second color, the third color, and the black color.

5. the third color light is blue light; the first color layer is a red fluorescent layer that emits red light as the first color when illuminated with the blue light from the outside, the second color layer is a green fluorescent layer that emits green light as the second color when illuminated with the blue light from the outside, The printed matter according to claim 4 , wherein the color absorbing layer is a yellow layer having a color complementary to the blue light.

6. The printed matter according to claim 5 , wherein the color absorbing layer includes a first color absorbing layer that is the yellow layer and a second color absorbing layer that is a blue absorbing layer that absorbs the blue light.

7. A method for verifying the authenticity of a printed matter according to any one of claims 2 to 6, comprising: illuminating the printed matter with light of the third color; comparing the image revealed by illumination with the third color light with an authentic image; The verification method includes a step of determining that the printed matter is genuine if the visualized image and the authentic image match as a result of the comparison, and determining that the printed matter is not genuine if they do not match.

8. 8. The verification method according to claim 7, which is performed by an information terminal including a white light source that emits white light, and an optical filter that extracts the third color light from the white light emitted from the white light source, The verification method includes a step of obtaining the third color light illuminated in the illuminating step by passing the white light emitted from the white light source through the optical filter.

9. The verification method according to claim 8 , wherein the information terminal is a smartphone, and the white light source is an LED light mounted on the smartphone.

10. A verification system for verifying the authenticity of a printed matter according to any one of claims 2 to 6, comprising: a white light source that emits white light; an optical filter that extracts the third color light from the white light emitted from the white light source; a comparison unit that compares the image visualized by illuminating the printed matter with the third color light with a genuine image; a determination unit that determines that the printed matter is genuine when the visualized image and the authentic image match, and determines that the printed matter is not genuine when they do not match; A verification system comprising:

11. an imaging unit that captures an image visualized by illuminating the printed matter with the third color light; The verification system according to claim 10 , wherein the comparison unit compares the image captured by the imaging unit with the authentic image.

12. 12. The verification system of claim 11, wherein the verification system is realized by a smartphone and an optical filter, the white light source and the imaging unit are an LED light and a camera provided in the smartphone, A verification system in which the comparison unit and the determination unit are realized by a program installed on the smartphone.

Images