Authentication printouts and methods for determining authenticity

Abstract

To provide an authentification medium in which it is difficult for the fluophor used in the fluophor luminescent ink to be identified.SOLUTION: Provided is a printed matter 10-1 for authentification, including a printed layer 2-1 for authentification for authenticity discrimination on at least part of a substrate 1, and characterized in that it contains a fluophor that emits visible light having a particular peak wavelength when irradiated with ultraviolet ray, and a fluophor that emits light in the infrared region when excited by the visible light.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an authentication print and an authenticity determination method using the same. [Background technology]

[0002] New anti-counterfeiting technologies must always be incorporated to prevent third parties from counterfeiting or tampering with valuable printed matter such as securities, cards, and travel tickets, certificates that certify or authenticate a person's identity such as driver's licenses, passports, and insurance cards, and marks attached to identification media such as stickers that certify the authenticity of items. Furthermore, there is a demand for the evolution of authenticity determination methods that enable the determination of whether an identification medium is genuine or not.

[0003] Technologies for preventing counterfeiting of marks include micro-text, copy prevention patterns, and printed matter using infrared absorbing ink or fluorescent ink.

[0004] Of these methods, those using fluorescent inks are difficult to see under normal visible light, so inks are used that make the mark detectable by visual inspection or with the aid of a detector when exposed to ultraviolet or infrared light.

[0005] A widely known method of using such fluorescent ink is to irradiate it with light in the ultraviolet or visible range and cause it to emit visible light (red, green, yellow, etc.), allowing for visual authentication of the ink.

[0006] There is also known a technology for authenticating marks or codes by irradiating them with light in the visible light region and the infrared light region and emitting infrared light (Patent Document 1).

[0007] These technologies rely on one specific wavelength to determine authenticity, making them susceptible to easy decoding and counterfeiting.

[0008] Also, there is known an authentication technology that forms two regions containing two different phosphors, and utilizes the difference in color pattern due to the difference in the visible emission color when the regions are excited with two different ultraviolet light regions to emit visible light (Patent Document 2). However, even with this technology, the phosphor used may be identified by visually observing the visible emission from the subject while changing the wavelength of ultraviolet light.

[0009] Authentication prints that are read using multiple different wavelengths of light have also been proposed. For example, one method involves moving the print and irradiating it with visible light, ultraviolet light, and infrared light in sequence using separate irradiation devices, detecting the light emitted from the print, obtaining three signals, and comparing the waveforms of the signals obtained for a genuine product to determine its authenticity. However, this technology also uses the same principle as the method of determining authenticity using specific wavelengths, and there is a high possibility that it can be easily deciphered.

[0010] However, the three main combinations of the wavelength of light irradiated and the wavelength of light detected are infrared light irradiation-infrared light detection, visible light irradiation-visible light detection, and ultraviolet light irradiation-ultraviolet light detection, making it easy for a counterfeiter to identify the ink or printing method, and the security level is not sufficiently high.

[0011] Also, an image display has been proposed that uses both infrared and ultraviolet light to determine authenticity (Patent Document 3). Conventionally, when only ultraviolet light-emitting phosphors were used, the ultraviolet light-emitting phosphors could become unrecognizable due to degradation, but this technology includes patterns and letters made of infrared light-emitting phosphors, so that whether they are irradiated with ultraviolet light or infrared light, the patterns and letters emerge, making it possible to determine authenticity.

[0012] However, this technology also involves shining excitation light onto the printed material, which is the authentication medium, and detecting or visually checking the light that comes out of the printed material due to that excitation light. Therefore, there is a high possibility that an would-be counterfeiter could irradiate the printed material they wish to counterfeit with ultraviolet or infrared excitation light and detect or visually check the fluorescence from the printed material, thereby identifying what type of phosphor is used and potentially deciphering the material. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] JP 2007-136838 A [Patent Document 2] Patent No. 5699313 [Patent Document 3] Japanese Patent Application Publication No. 10-129107 Summary of the Invention [Problem to be solved by the invention]

[0014] In view of the above circumstances, an object of the present invention is to provide an authentication medium in which it is difficult to identify the phosphor used in the phosphor-emitting ink. [Means for solving the problem]

[0016] The first aspect of the present invention is A non-certification printing layer is formed on at least a part of a substrate, and a certification printing layer for authenticity determination is formed on a part of the non-certification printing layer in a tweezers-matched manner. The authentication printing layer is A first phosphor that emits visible light having a specific peak wavelength when irradiated with ultraviolet light; and a second phosphor that emits light in the infrared region when excited by the visible light emitted from the first phosphor.

[0019] The particular peak wavelength may be 450 nm.

[0020] The light in the infrared region may have a peak wavelength in the range of 700 nm to 1000 nm.

[0021] The visible light excitation layer may include one or more selected from a pattern, a character, a one-dimensional code, and a two-dimensional code.

[0022] The second aspect of the present invention is a method for manufacturing a semiconductor device according to any one of claims 1 to 4. A method for determining authenticity using an authentication printout, comprising: A step of detecting infrared light emitted from the authentication print layer by irradiating the authentication print with ultraviolet light; The authenticity determining method is characterized by comprising an authenticity determining step of determining the product as genuine if the light in the infrared region is detected, and determining the product as counterfeit if the light is not detected. Effect of the Invention

[0023] According to the authentication print of the present invention, the printing layer formed on the substrate is provided with an ultraviolet excitation layer containing a material that emits visible light when irradiated with ultraviolet light, and a visible light excitation layer containing a material that emits light in the infrared region when excited by visible light. Therefore, when irradiated with ultraviolet light, it emits fluorescence in the visible light region, but the fluorescence does not contain any information used for authenticity determination. Authenticity determination is performed by the fluorescence in the infrared region emitted when irradiated with visible light, but even when irradiated with visible light, it is not noticeable to the naked eye that the infrared light used for authenticity determination is being emitted. Therefore, it is possible to provide an authentication medium in which it is difficult to identify the phosphor used in the phosphor luminous ink.

[0024] In addition, the authenticity determination method of the present invention is a method for determining authenticity using the authentication printed matter of the present invention, in which it is difficult to identify the phosphor used. Therefore, it is possible to provide a method for determining authenticity in which it is difficult to identify the phosphor used in the phosphor luminous ink, and at the same time, it is possible to reliably determine authenticity. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a cross-sectional explanatory diagram illustrating a layer structure of the authentication printed matter of the present invention. [Diagram 2] FIG. 2 is a cross-sectional explanatory diagram illustrating a layer structure of the authentication printed matter of the present invention. [Diagram 3] FIG. 2 is a cross-sectional explanatory diagram illustrating a layer structure of the authentication printed matter of the present invention. [Figure 4] FIG. 2 is a cross-sectional explanatory diagram illustrating a layer structure of the authentication printed matter of the present invention. [Diagram 5] FIG. 2 is an explanatory diagram illustrating an example of a method for determining authenticity using an authentication printed matter of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] <Authentication Printout> First to fourth embodiments of the authentication printed matter of the present invention will be described with reference to FIGS. First embodiment As shown in FIG. 1, an authentication printed matter 10-1 of the present invention is an authentication printed matter having, on at least a part of a substrate 1, an authentication printed layer 2-1 for determining authenticity. The authentication print layer 2-1 contains a phosphor that emits visible light having a specific peak wavelength when irradiated with ultraviolet light, and a phosphor that emits light in the infrared region when excited by the visible light. The specific peak wavelength may be 450 nm. Furthermore, the light in the infrared region excited by visible light having a peak wavelength at 450 nm and emitted may be infrared light having a peak wavelength in the range of 700 nm to 1000 nm.

[0027] (base material) The substrate 1 may be any substrate made of a material capable of forming a print layer, and the form and material are not particularly limited within that range. For example, various types of paper and films or sheets made of various resins can be suitably used. A metal sheet may also be used. Examples of materials for the substrate 1 include papers such as condenser paper and paraffin paper, and plastic films such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cellophane, polycarbonate, polyvinyl chloride, polystyrene, polyimide, nylon, and polyvinylidene chloride. The thickness of the substrate 1 is 10 to 300 μm, and preferably 50 to 200 μm.

[0028] However, it is preferable that the base material 1 does not contain a fluorescent whitening agent in order to prevent the light emitted from the phosphor contained in the authentication printing layer, which emits visible light with a specific peak wavelength when irradiated with ultraviolet light, from becoming difficult to see.

[0029] (Authentication printing layer) The authentication printing layer 2-1 is a layer made of printable ink. The ink is composed of a medium to which phosphor a, which emits visible light with a specific peak wavelength when irradiated with ultraviolet light (described later), and phosphor b, which emits light in the infrared range when excited by visible light, have been added. The medium is a varnish used for printing ink alone, or an achromatic dilution ink in which only an extender pigment is dispersed. It is preferable that phosphor a and phosphor b are mixed uniformly in a weight ratio of 50:50.

[0030] Specifically, two types of phosphors a and b described later are mixed in a weight ratio of 50:50 in a medium, and then the mixture is made into a printing ink such as a UV printing ink (e.g., FD Karton X series, manufactured by Toyo Ink SC Holdings) so that the phosphor is present in an amount of 2% by weight to 30% by weight, and more preferably 5% by weight to 20% by weight.

[0031] The authentication printed layer 2-1 has a thickness of 0.5 μm to 10 μm, and preferably 1 μm to 5 μm.

[0032] (Phosphor) Examples of phosphor a that emits visible light with a specific peak wavelength of 450 nm when irradiated with ultraviolet light include diaminostilbene, imidazole, thiazoline, oxazole, 2,5-thiophenediyl (5-tert-butyl-1,3-benzoxazole) [Tinopal OB (BASF product)], etc.), triazole, oxadiazole, thiadiazole, coumarin, naphthylimide, pyrazoline, pyrene, imidazolone, benzidine, diaminocarbazole, oxacyanine, methine, pyridine, anthrapyridazine, distyryl, carboxylevostyryl, indole, quinolinone, etc. Oxazole is preferably used.

[0033] In addition, examples of phosphor b that emits light in the infrared region when excited by visible light having a specific peak wavelength of 450 nm include compounds containing Cr, Y, Lu, Gd, Ga, Al, Sc, etc. as constituent elements. Specifically, when it contains ScBO3:Cr, Both are Y3Al5O 12 :Ce phosphor, CaAlSiN3 phosphor, ScCaAlSiN3 phosphor, ScBO3:Cr phosphor, (Ba, Sr)2SiO4:Eu phosphor, (Lu, Y, Gd)3Al 15 O 12 : Ce phosphor, La3Si6N 11 : Ce phosphor, α-sialon phosphor. At least Y3Al5O 12 The above notation (Lu, Y, Gd) indicates that at least one element selected from Lu, Y, and Gd is contained.

[0034] The method for forming the authentication printing layer 2-1 is not particularly limited as long as it is a method using a means capable of forming the authentication printing layer 2-1 on the substrate 1. For example, lithographic printing, intaglio printing, letterpress printing, and offset printing thereof can be used. Screen printing and transfer printing may also be used. Inkjet printing may also be used.

[0035] Although not shown in the figure, a protective layer may be provided on the authentication printing layer 2-1. The material of the protective layer is preferably one that has a high transmittance of 80% or more in the visible light region and the infrared region, and has higher mechanical strength and surface hardness than the authentication printing layer 2-1.

[0036] The present invention is characterized in that phosphor b is excited by visible light emitted from phosphor a, and emits light in the infrared region from phosphor b.

[0037] Due to these characteristics, if a person who is trying to counterfeit the authentication printed layer 2-1 of the authentication printed matter 10-1 of the present invention irradiates it with ultraviolet light in order to identify the phosphor used therein, it emits fluorescence in the visible light range, but this fluorescence is not used for authentication. In addition, even if visible light is irradiated, infrared light that cannot be observed by the naked eye is emitted, so it cannot be seen by the naked eye and is not noticed. In addition, since infrared light is not emitted unless visible light with a specific peak wavelength is irradiated, even if visible light without a specific peak wavelength is irradiated, the emitted infrared light is extremely weak. Therefore, only phosphor a, which emits visible light with a specific peak wavelength when irradiated with ultraviolet light, can be detected by a person who is trying to counterfeit the authentication printed matter 10-1 of the present invention. Therefore, it is difficult to identify phosphor b, which is excited by light in the visible light range and emits fluorescence in the infrared range.

[0038] By virtue of this mechanism, the authentication printed matter 10-1 of the present invention can provide an authentication medium in which it is difficult to identify the phosphor used in the phosphor-emitting ink.

[0039] The authentication printing layer 2-1 may be solidly formed over at least the entire surface of one side of the substrate 1, or may be solidly formed on a portion of one side of the substrate 1. Here, solid formation refers to a state in which the authentication printing layer is uniformly formed without a pattern. Also, some pattern may be formed. For example, a picture, a character, a barcode, a two-dimensional code, or the like may be formed by printing. Any one of these, or a combination of two or more of them may be used.

[0040] Second embodiment FIG. 2 is a cross-sectional explanatory diagram illustrating an authentication print 10-2 according to a second embodiment of the present invention. The authentication printed matter 10-2 of the second embodiment of the present invention is an authentication printed matter in which a non-authentication printed layer 6 is formed on at least a part of a substrate 1, and an authentication printed layer 2-2 for authenticity determination is formed in a tweezers-matched manner on a part of the non-authentication printed layer 6. The material and formation method of the authentication printed layer 2-2 may be the same as or equivalent to those of the authentication printed layer 2-1.

[0041] The authentication printed layer 2-2 may be formed from the same ink as the authentication printed layer 2-1 of the first embodiment.

[0042] The non-authentication printed layer 6 is not an authentication printed layer, and does not contain any phosphor or other additives. A printed layer is a layer on which pictures or characters are printed using normal printing inks. A printed layer is a layer on which process inks such as cyan, magenta, yellow, and black are used, or special color inks are used.

[0043] The method of forming the certification printing layer 2-2 on a part of the non-certification printing layer 6 in a tweezers-matching manner is to first print the certification printing layer 2-2, which is an information section such as a barcode, by offset printing using ultraviolet-excited infrared emitting ink (UV offset ink). Next, the non-certification printing layer 6, which is an information camouflage section, can be printed in a tweezers-matching manner with the certification printing layer 2-2 using a camouflage ink (UV-curable offset ink) whose hue appears to be the same color as the ultraviolet-excited infrared emitting ink under visible light irradiation, and a printing plate that is black and white inverted from the printing plate on which the certification printing layer 2-2 was printed.

[0044] Third embodiment FIG. 3 is a cross-sectional explanatory diagram illustrating an authentication print 10-3 according to a third embodiment of the present invention. The authentication printed matter 10-3 of the third embodiment of the present invention is an authentication printed matter having an authentication printed layer 2-3 for authenticity determination on at least a part of the substrate 1. The material and forming method of the authentication printed layer 2-3 may be the same as or equivalent to those of the authentication printed layer 2-1.

[0045] The authentication printing layer 2-3 is provided on a substrate 1 with, in this order, an ultraviolet excitation layer 7 containing a material that emits visible light with a specific peak wavelength when irradiated with ultraviolet light, and a visible light excitation layer 8 containing a material that emits light in the infrared range when excited by visible light.

[0046] Since the ultraviolet light excitation layer 7 is formed under the visible light excitation layer 8, deterioration of the ultraviolet light excitation layer 7 can be suppressed both under natural light and when exposed to ultraviolet light.

[0047] The method for producing the authentication print 10-3 may be such that first, the ultraviolet excitation layer 7 is printed on the base material 1, and then the visible light excitation layer 8 is printed. In other respects, the authentication printout 10-3 can be obtained in the same manner as in the first embodiment.

[0048] (Fourth embodiment) FIG. 4 is a cross-sectional explanatory diagram illustrating an authentication print 10-4 according to a fourth embodiment of the present invention. The authentication printed matter 10-4 of the fourth embodiment of the present invention has a configuration in which, in the authentication printed layer 2-3 of the authentication printed matter 10-3 of the third embodiment, the ultraviolet excitation layer 7 containing a material that emits visible light having a specific peak wavelength when irradiated with ultraviolet light and the visible light excitation layer 8 containing a material that emits light in the infrared range when excited by visible light are interchanged. In other respects, the authentication printout 10-4 can be obtained in the same manner as in the first embodiment.

[0049] <How to determine authenticity> Next, the method for determining authenticity using the authentication print of the present invention will be described with reference to FIG.

[0050] The authenticity determination method of the present invention is a method for determining authenticity using any one of the authentication printed matter 10-1, 10-2, 10-3, and 10-4 described in the first to fourth embodiments.

[0051] The authenticity determination method of the present invention includes a step of detecting fluorescence (light in the infrared range having a specific peak wavelength) emitted from the authentication printed layer 2 by irradiating the authentication printed matter 10 with ultraviolet light emitted from an ultraviolet light irradiation light source 4, and an authenticity determination step of determining the matter as authentic if light in the infrared range is detected, and determining the matter as a fake if it is not detected.

[0052] (Light source for ultraviolet light irradiation) The ultraviolet light source 4 is not particularly limited as long as it is a light source capable of emitting ultraviolet light in a predetermined wavelength region.

[0053] (Means for detecting light in the infrared range) The means for detecting infrared light used in the process of detecting infrared light does not need to be particularly limited as long as it is an infrared sensor having sensitivity in the infrared region or an infrared camera using an infrared sensor. Also, as illustrated in FIG. 5, a filter 5 may be provided in front of the infrared receiving element 3. The filter 5 is used for the purpose of reducing noise contained in the infrared light in the light incident on the infrared receiving element 3 from the surrounding environment or the ultraviolet light irradiation light source 4. As the filter 5, for example, a bandpass filter that transmits the peak wavelength of the infrared light emitted from the authentication printing layer 2 and does not transmit other wavelengths can be suitably used.

[0054] There are two types of infrared sensors: quantum type (cooled type) and thermal type (uncooled type). The quantum type (cooled type) can use photodiodes, phototransistors, and photo ICs (Integrated Circuits) made of semiconductors with a narrow band gap corresponding to the energy of infrared light. Compared to the thermal type (uncooled type), it has high sensitivity (100 to 1000 times) and high-speed response. The sensor part is placed in a vacuum device and a cooling device is required to cool it to -213℃ to -173℃. On the other hand, the thermal type (uncooled type) detects changes in electrical properties by utilizing the fact that the element temperature rises when the sensor is heated by heat from receiving infrared light. Although it has lower sensitivity and response speed than the quantum type, it has the advantage that in principle it has a wide wavelength band and does not need to be cooled. For the above reasons, thermal type (uncooled type) infrared sensors are usually used.

[0055] (Method of determining authenticity) In the authenticity determination process, in which if light in the infrared region is detected, it is determined to be genuine, and if light in the infrared region is not detected, it is determined to be counterfeit, the means for determining authenticity is not particularly limited, but for example, a personal computer may be used.

[0056] Specifically, the signal from the infrared sensor is input into a personal computer via an interface, and authenticity can be determined using an application program that determines that infrared rays have been detected if the signal from the infrared sensor is above a certain threshold, and determines that infrared rays have not been detected if the signal is below the threshold.

[0057] Instead of a general-purpose personal computer, a microprocessor unit equipped with the above-mentioned signal processing program can also be used. EXAMPLES

[0058] Next, an embodiment of the present invention will be described.

[0059] <Example 1> An authentication printed matter was created having the same configuration as the authentication printed matter 10-1 illustrated in Fig. 1. That is, an authentication printed matter having an authentication printed layer on a substrate was created.

[0060] The substrate used was Shiraoi (manufactured by Nippon Paper Industries Co., Ltd.).

[0061] In addition, the following materials were used as a phosphor (ultraviolet-excited material) contained in the authentication printing layer that emits visible light with a specific peak wavelength of 450 nm when irradiated with ultraviolet light, and a phosphor that emits light in the infrared range when excited by that visible light.

[0062] A;Tinopal OB (manufactured by BASF) was used as a phosphor (visible light excitation material) that emits visible light having a specific peak wavelength of 450 nm when irradiated with ultraviolet light.

[0063] In addition, B; NIR-2 (manufactured by DYDEN Co., Ltd.) was used as a phosphor that emits light having a peak wavelength in the infrared region ranging from 700 nm to 1000 nm when excited by visible light having a specific peak wavelength of 450 nm.

[0064] The fluorescent ink was prepared by kneading these phosphors A and B in a weight ratio of 50:50 into a medium so that the phosphors accounted for 20% by weight.

[0065] The ratio of phosphor A to phosphor B was determined based on the results of a previous study of the additive ratio (Table 1). In studies 1 to 3, the authenticity judgment results when the ultraviolet ray excited material:visible light excited material were 30% by weight:70% by weight, 50% by weight:50% by weight, and 70% by weight:30% by weight, respectively, were indicated by ◯ and △. In studies 1 and 3, the authenticity judgment result was △. In study 2, that is, when the ultraviolet ray excited material:visible light excited material was 50% by weight:50% by weight, a good authenticity judgment result was obtained. Therefore, the ratio of phosphor A to phosphor B in the above printing ink was also set to 50% by weight:50% by weight.

[0066] [Table 1]

[0067] The printing ink prepared above was printed on almost the entire surface of the substrate using a sheet-fed gravure offset printing device, and then the printing ink was cured by irradiating it with ultraviolet light to obtain an authentication print of Example 1.

[0068] <Example 2> First, the non-certification printing layer was printed on the substrate. The ink used for printing the non-certification printing layer was the following process ink, which was mixed to have the same color as the certification printing layer. FD OL Yellow TC Blue (Toyo Ink Mfg. Co., Ltd.) FD OL Red TC Red (Toyo Ink Mfg. Co., Ltd.) FD OL Indigo TC Blue (Toyo Ink Mfg. Co., Ltd.)

[0069] The printing device used was gravure offset printing. The plate used was a reverse plate that printed the authentication printing layer and a black and white inverted pattern except for a part of the base material. A black and white inverted two-dimensional code about 10 mm square was printed on one part of it.

[0070] First, a non-authentication printing layer was printed on the substrate using the toned ink. A printout was obtained in which a 10 mm square two-dimensional code pattern was printed inversely on part of the non-authentication printing layer.

[0071] After drying the print, a two-dimensional code was printed in the area where the inverted two-dimensional code pattern was printed, in the same manner as in Example 1. Except for the above, the same procedure was followed as in Example 1 to obtain the authentication print of Example 2.

[0072] <Example 3> First, an ultraviolet excitation layer containing a material that emits visible light with a specific peak wavelength of 450 nm when irradiated with ultraviolet light was printed on the substrate. Next, a visible light excitation layer containing a material that emits light in the infrared region of 700 nm to 1000 nm when excited by the visible light emitted from the ultraviolet excitation layer was printed on the ultraviolet excitation layer, and the authentication print of Example 3 was obtained by carrying out the same procedure as in Example 1, except that the visible light excitation layer containing a material that emits light in the infrared region of 700 nm to 1000 nm when excited by the visible light emitted from the ultraviolet excitation layer was printed on the ultraviolet excitation layer.

[0073] <Example 4> First, a visible light excitation layer containing a material that emits light having a peak wavelength in the infrared range of 700 nm to 1000 nm when excited by visible light was printed on the substrate. Next, an ultraviolet light excitation layer containing a material that emits visible light having a specific peak wavelength of 450 nm when irradiated with ultraviolet light was printed on the visible light excitation layer, and the authentication print of Example 4 was obtained by carrying out the same procedure as in Example 1, except that the ultraviolet light excitation layer was printed on the visible light excitation layer.

[0074] <Comparative Example 1> An authentication print of Comparative Example 1 was obtained in the same manner as in Example 1, except that the weight ratio of phosphor A (ultraviolet light excited material) and phosphor B (visible light excited material) was 30:70.

[0075] <Comparative Example 2> An authentication print of Comparative Example 1 was obtained in the same manner as in Example 1, except that the weight ratio of phosphor A (ultraviolet light excited material) and phosphor B (visible light excited material) was 70:30.

[0076] <Authenticity test> The authenticity determination was performed using the authenticity determination device 20 illustrated in FIG. 5, using the authentication printed matter obtained in Examples 1 to 4.

[0077] The authenticity determination device 20 includes an ultraviolet ray irradiation light source 4 that irradiates the authentication printed layer 2 of the authentication printed matter 10 with ultraviolet rays. In an authenticity determination test, the authentication printed layer 2 of the authentication printed matter 10 is irradiated with ultraviolet rays. Then, visible light having a specific peak wavelength of 450 nm is emitted from a phosphor in the authentication printed layer 2 that emits visible light when irradiated with ultraviolet rays. When excited by the visible light, infrared rays having a peak wavelength in the range of 700 nm to 1000 nm are emitted from a phosphor that emits light in the infrared region.

[0078] In the authentication printed materials obtained in Examples 1 to 4, as shown in Study 2 in Table 1, the authentication printed layer 2 was formed using an ink composition that had been designed to produce good results in the authenticity determination test, and all of them achieved good authenticity determination results.

[0079] In the authentication printed materials obtained in Comparative Examples 1 and 2, as shown in Studies 1 and 3 in Table 1, the authentication printing layer 2 was formed using an ink composition that had previously shown poor results in authenticity determination tests, and therefore the authenticity determination results were not all good. [Explanation of symbols]

[0080] 1...Base material 2, 2-1, 2-2, 2-3, 2-4: Authentication printing layer 3. Infrared light receiving element 4...Light source for ultraviolet light irradiation 5. Filters 6. Non-certified printing layer 7. Ultraviolet excitation layer 8. Visible light excitation layer 10, 10-1, 10-2, 10-3, 10-4...Certification printout 20 Authenticity determination device

Claims

1. A non-certification printing layer is formed on at least a part of a substrate, and a certification printing layer for authenticity determination is formed on a part of the non-certification printing layer in a tweezers-matched manner. The authentication printing layer is A first phosphor that emits visible light having a specific peak wavelength when irradiated with ultraviolet light; and a second phosphor that emits light in the infrared region when excited by the visible light emitted from the first phosphor.

2. 2. The authentication print according to claim 1, wherein the specific peak wavelength is 450 nm.

3. 3. The authentication printed matter according to claim 1, wherein the light in the infrared region has a peak wavelength in the range of 700 nm to 1000 nm.

4. The authentication printed matter according to any one of claims 1 to 3, characterized in that the authentication printing layer comprises one or more selected from a picture, a character, a one-dimensional code, and a two-dimensional code.

5. A method for determining authenticity using an authentication print according to any one of claims 1 to 4, comprising: A step of detecting infrared light emitted from the authentication print layer by irradiating the authentication print with ultraviolet light; The authenticity determining method is characterized by comprising an authenticity determining step of determining the product as genuine when the light in the infrared region is detected, and determining the product as counterfeit when the light is not detected.

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