Information recording body, printed matter, and reading device and reading method for information recording body

Abstract

The present invention addresses the problem of providing: an information recording body which can be easily read and deciphered by a typical reading device and for which reproduction or the like is difficult; and a reading device or the like for said information recording body. This information recording body 1 comprises a substrate 2, a bright ink layer 5 formed from bright ink on one surface of the substrate 2, a colored ink layer 3 formed from colored ink, and a transparent ink layer 4 formed from transparent ink. The colored ink layer 3 forms a first pattern 100, and the transparent ink layer 4 forms a second pattern 200. In plan view, at least part of the first pattern 100 and the second pattern 200 overlaps with a region where the bright ink layer 5 is formed. The second pattern 200 includes information that can be converted into a specific code, and in plan view, at least part of the second pattern 200 overlaps with the first pattern 100.

Description

Information recording medium, printed matter, information recording medium reading device and reading method

[0001] The present invention relates to an information recording medium that is difficult to counterfeit, and an anti-counterfeit printed matter including the same.

[0002] 2. Description of the Related Art Conventionally, digital watermarking technology has been used to embed information in printed matter or the like at a level that is not visually recognizable to humans, and to read the embedded information with a reading device without impairing the aesthetic appearance of the printed matter.

[0003] As an example of a printed matter using digital watermark technology, Patent Document 1 listed below describes an information recording medium having a composite image including an image printed on a glossy layer and an image formed on the image and printed as a transparent layer. In this information recording medium, both images are printed using inks that reflect different amounts of light depending on the observation angle, and the composite image allows one image to be recognized depending on the observation angle. Furthermore, the image printed on the glossy layer is an image having regularity in feature points in the spatial frequency domain, and the image printed on the transparent layer is an image in which feature points in the spatial frequency domain are positioned to disrupt that regularity.

[0004] JP 2016-93895 A

[0005] In this case, by adjusting the observation angle of a dedicated reading device, image information printed on the glossy layer of the printed material, which has a regularity in feature points in the spatial frequency domain, can be read and decoded. However, to decode information embedded using digital watermarking technology, the reading device must generally be equipped with a decoding application program with a dedicated algorithm, which may make it difficult to easily use a general-purpose reading device such as a smartphone. Furthermore, the appearance of the image information to be read on the printed material is difficult to visually recognize, making it difficult to visually determine which parts of the image information to read, which may affect usability. On the other hand, codes that can be read by general reading devices include OCR characters, barcodes, and two-dimensional codes. However, these codes are easily copied and counterfeited, and if used as is, they may pose a risk to determining the authenticity of the printed material and ensuring safety.

[0006] The present disclosure has been made in consideration of such circumstances, and aims to provide an information recording medium, printed matter, and a reading device for the information recording medium that are easy to read and decode using a general reading device, and difficult to copy, etc.

[0007] The information recording medium according to this embodiment is an information recording medium comprising a substrate, a first layer formed on one side of the substrate using a photoluminescent material, a second layer formed on the one side using a colored ink, and a third layer formed on the one side using a transparent ink, wherein the second layer forms a first pattern, the third layer forms a second pattern, and in a planar view, at least a portion of the first pattern and the second pattern each overlap with the area in which the first layer is formed, and the second pattern includes information that can be converted into a specific code, and in a planar view, at least a portion of the second pattern overlaps with the first pattern.

[0008] In the information recording medium according to another embodiment of the present invention, the first layer may be formed as a solid, or may be formed as halftone dots or lines with a halftone dot area ratio of 80% or more.

[0009] In the information recording medium according to another embodiment of the present invention, the second pattern may be made up of a plurality of partial patterns.

[0010] In addition, in an information recording medium according to another embodiment of the present invention, only some of the partial patterns among the plurality of partial patterns may contain information that can be converted into the specific code.

[0011] In addition, in an information recording medium according to another embodiment of the present invention, the second pattern may be a two-dimensional code consisting of a plurality of partial patterns, each of which has one or more cut-out symbols, and all of the cut-out symbols are arranged at the ends of the second pattern.

[0012] Furthermore, in an information recording medium according to another embodiment of the present invention, the second pattern is composed of a plurality of partial patterns, and when the plurality of partial patterns are a first partial pattern, a second partial pattern, and a third partial pattern sandwiched between the first partial pattern and the second partial pattern, a first cut-out symbol arranged on the second partial pattern side of the first partial pattern and a second cut-out symbol arranged on the first partial pattern side of the second partial pattern constitute cut-out symbols in at least two locations of the third partial pattern, and the third partial pattern may constitute dummy information that cannot be converted into the specific code.

[0013] In the information recording medium according to another embodiment of the present invention, the first pattern may include information that can be converted into a specific code different from the second pattern.

[0014] In addition, in an information recording medium according to another embodiment of the present invention, when viewed in a plane, the entire area of ​​the second pattern may overlap with a portion of the first pattern, and the portion of the first pattern may have a lower dot area ratio than the remaining portion.

[0015] Furthermore, in an information recording medium according to another embodiment of the present invention, the third layer may be composed of the transparent ink that is excited by infrared or ultraviolet light and emits visible light, or may be composed of ink containing an infrared absorbing material, or may be composed of ink containing a polarizing material.

[0016] The printed matter according to this embodiment may include any of the above information recording media.

[0017] A reading device for reading any of the above-mentioned information recording bodies according to this embodiment comprises an illumination light source, a reading unit positioned close to the illumination light source, and a control unit, wherein the control unit turns on the illumination light source, causes the reading unit to read one side of the information recording body, and when first information is read, outputs guidance to change the reading angle of the reading device according to the information read, and after outputting the guidance, causes the reading unit to read one side of the information recording body and determines whether second information different from the first information has been read.

[0018] In addition, in a reading device according to another embodiment of the present invention, the first pattern of the information recording medium includes information that can be converted into a specific code different from the second pattern, and the control unit may, when the first information is the second pattern, output the guidance to change the reading angle of the reading device to a diagonal direction relative to the surface of the information recording medium, and determine whether the first pattern has been read as the second information.

[0019] In addition, in a reading device according to another embodiment of the present invention, the first pattern of the information recording medium includes information that can be converted into a specific code different from the second pattern, and the control unit may, when the first information is the first pattern, output the guidance to change the reading angle of the reading device perpendicular to the surface of the information recording medium, and determine whether the second pattern has been read as the second information.

[0020] In addition, a reading device according to another embodiment of the present invention comprises an illumination light source, a reading unit arranged in proximity to the illumination light source, and a control unit, wherein the first pattern of the information recording body contains information that can be converted into a specific code different from the second pattern, and the control unit causes the reading unit to read one side of the information recording body while the illumination light source is turned off, and when the first pattern is read, turns on the illumination light source and causes the reading unit to read one side of the information recording body, and determines whether the second pattern has been read.

[0021] In addition, in another form of the reading device of this embodiment, when the first pattern is read, the control unit may turn on the illumination light source, shield all areas readable by the reading unit except for a specified area so that they cannot be read, and cause the reading unit to read one side of the information recording medium.

[0022] The method for reading the information recording medium according to this embodiment includes the steps of: the reading device turning on the illumination light source; having the reading unit read one side of the information recording medium; when first information is read, outputting guidance to change the reading angle of the reading device according to the read information; after outputting the guidance, having the reading unit read one side of the information recording medium; and determining whether second information different from the first information has been read.

[0023] In addition, a reading method according to another embodiment of the present invention includes a step in which the first pattern of the information recording medium includes information that can be converted into a specific code different from the second pattern, and the reading device has the steps of causing the reading unit to read one side of the information recording medium while the illumination light source is turned off, turning on the illumination light source and causing the reading unit to read one side of the information recording medium when the first pattern has been read, and determining whether the second pattern has been read.

[0024] According to this embodiment, it is possible to provide an information recording medium, a printed matter, and a reading device for an information recording medium that can be easily read and decoded by a general reading device and is difficult to copy.

[0025] 1 is a plan view and a side view of an information recording medium according to a first embodiment; FIG. 2 is a diagram illustrating differences in appearance of the information recording medium depending on the observation angle; FIG. 3 is a configuration diagram illustrating the configuration of a reading device and an authenticity determination device for an information recording medium according to the present disclosure; FIG. 4 is a flowchart relating to code identification of a second pattern and authenticity determination; FIG. 5 is a plan view of an information recording medium according to a second embodiment and a diagram illustrating differences in appearance depending on the observation angle; FIG. 6 is a plan view of a third embodiment and an information recording medium according to the third embodiment; FIG. 7 is a configuration diagram illustrating the configuration of a reading device according to a fourth embodiment; FIG. 8 is a flowchart relating to code identification of a first pattern; FIG. 9 is a flowchart relating to code identification of a second pattern; FIG. 10 is a configuration diagram illustrating the configuration of an authenticity determination device according to the fourth embodiment; FIG. 11 is a flowchart relating to code identification of a second pattern and authenticity determination; FIG. 12 is a plan view of information recording mediums according to a fifth and sixth embodiments; FIG. 13 is a plan view of an information recording medium according to a seventh embodiment; FIG. 14 is a plan view of an information recording medium according to an eighth embodiment; FIG. 15 is a plan view of an information recording medium according to a ninth and tenth embodiment; FIG. 16 is a plan view and a side view of a printed matter including an information recording medium according to an eleventh embodiment; FIG. 17 is a plan view of an information recording medium according to a twelfth embodiment; FIG. 18 is a table illustrating the superiority or inferiority of performance in terms of dot area ratio of colored inks. FIG. 10 is a diagram for explaining a method for calculating the dot area ratio of colored ink. FIG. 11 is a plan view and a side view of an information recording medium according to a thirteenth embodiment. FIG. 12 is a plan view of an information recording medium according to a fourteenth embodiment. FIG. 13 is a diagram for explaining differences in how an information recording medium appears depending on the observation angle of a reading device. FIG. 14 is a first flow chart relating to reading of an information recording medium by a reading device. FIG. 15 is a second flow chart relating to reading of an information recording medium by a reading device. FIG. 16 is a third flow chart relating to reading of an information recording medium by a reading device. FIG. 17 is a diagram showing an example of processing by a reading device relating to reading of an information recording medium in the third flow.

[0026] Hereinafter, examples of the information recording medium, printed matter, and authenticity determination device of the present disclosure will be described with reference to the drawings, etc. However, the information recording medium, etc. of the present disclosure is not limited to the embodiments and examples described below.

[0027] The figures shown below are schematic illustrations. Therefore, the size and shape of each part are appropriately exaggerated to facilitate understanding. Furthermore, hatching indicating the cross section of a member is omitted as appropriate in each figure. The numerical values ​​such as dimensions of each member and the names of materials described in this specification are examples of embodiments and are not limited to these, and may be selected and used as appropriate. In this specification, terms specifying shapes or geometric conditions, such as parallel, orthogonal, and perpendicular, are intended to include not only their strict meanings but also substantially the same state.

[0028] 1. First Embodiment A first embodiment of the information recording medium of the present disclosure will be described. Fig. 1(a) is a plan view illustrating an information recording medium 1 according to the first embodiment, and Fig. 1(b) is a side view thereof. The information recording medium 1 includes a substrate 2 and a glittering ink layer 5 formed on one surface of the substrate 2 from a glittering material. Also, on the same surface, opposite the substrate 2 from the glittering ink layer 5, are a colored ink layer 3 formed from a colored ink so as to cover a portion of the glittering ink layer 5, and a transparent ink layer 4 formed from a transparent ink that has the property of reflecting different amounts of light depending on the observation angle.

[0029] When the information recording medium 1 is viewed in a plan view from the thickness direction, the entire area of ​​the first pattern 100 formed by the colored ink layer 3 and the entire area of ​​the second pattern 200 formed by the transparent ink layer 4 each overlap with the area where the glitter ink layer 5 is formed. Furthermore, the second pattern 200 contains information that can be converted into a specific code, and at least a portion of it overlaps with the first pattern 100. The glitter ink layer 5, the colored ink layer 3, and the transparent ink layer 4 are examples of the first layer, the second layer, and the third layer, respectively.

[0030] (a) Structure of the Information Recording Medium The substrate 2 has printability and coating suitability for forming the glitter ink layer 5, the colored ink layer 3, and the transparent ink layer 4, and any film substrate is used to support these. Examples of the substrate 2 include polyester films such as polyethylene terephthalate film, polyethylene films, polypropylene films, polyethylene fluoride-based films, polyvinylidene fluoride films, polyvinyl chloride films, polyvinylidene chloride films, ethylene-vinyl alcohol films, polyvinyl alcohol films, polymethyl methacrylate films, polyethersulfone films, polyether ether ketone films, polyamide films, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer films, polyimide films, etc. The substrate 2 may also be paper, sticker / label paper, etc.

[0031] The substrate 2 may be opaque or transparent, and may be colored or colorless. In this embodiment, the substrate 2 is colored, for example, white. The thickness of the substrate 2 can also be determined arbitrarily depending on the application of the information recording medium 1, and may be thin enough to have appropriate flexibility, or thick enough to have almost no flexibility. In the former case, the thickness may be, for example, 0.1 μm or more and 1 mm or less, and in the latter case, the thickness may be, for example, greater than 1 mm.

[0032] The glittering ink constituting the glittering ink layer 5 can be, for example, an ink containing a glittering material that exhibits a silvery, bluish-gold, or reddish-gold color, such as aluminum, silver, copper, zinc, or tin powder, or iron phosphide. The glittering ink layer 5 containing such a glittering ink has the property of mainly diffusing and reflecting light when white light or the like is incident from an illumination light source. Note that, although the glittering ink layer 5 is used in this embodiment, a glittering layer may be used instead of the glittering ink layer 5. The glittering layer may be, for example, a layer formed by vapor-depositing aluminum or silver powder, or vapor-deposited paper formed by laminating a vapor-deposited film on paper. Even such a glittering layer has the property of mainly diffusing and reflecting light when white light or the like is incident from an illumination light source.

[0033] On the other hand, the colored ink constituting the colored ink layer 3 is composed of printing inks commonly used in printing for forming designs, etc., and it is sufficient that the process color, which is a non-transparent color, is visible as some kind of pattern or design. Furthermore, the colored ink may or may not contain a glittering material, and is not limited to the presence or absence of a glittering material. Here, if the colored ink contains a glittering material, the content of the glittering material is desirably small, for example, 3% by weight or less of the pigment, in order to differentiate it from the glittering ink layer 5. This is because the colored ink layer 3 is sufficient if it is visible or recognizable itself and can camouflage the pattern of the transparent ink layer 4 that is superimposed thereon to some extent. For example, it may be formed using an ink containing an acrylic, polyester, polyurethane, epoxy, or other resin mixed with an organic or inorganic coloring pigment, such as titanium oxide, phthalocyanine, or carbon black. Various types of colored inks can be applied, such as ultraviolet curing type, oxidative polymerization type, penetration type, heat drying type, evaporation drying type, etc. The way in which white light or the like is reflected when incident on the colored ink layer 3 containing such colored ink from an illumination light source depends on the surface quality of the colored ink layer 3, but normally, the diffuse reflection property is dominant.

[0034] The transparent ink constituting the transparent ink layer 4 can be, for example, a transparent varnish, ink varnish, transparent ink, or medium ink that does not use a coloring pigment. Various types of transparent inks are applicable, including ultraviolet curing, oxidative polymerization, penetration, heat drying, and evaporation drying. When white light or the like is incident from an illumination light source, the transparent ink layer 4 containing such a transparent ink has a property in which the ratio of emitted light to incident light fluctuates, mainly in the direction of specular reflection, where the angle of incidence and the angle of emission are approximately equal. In other words, the ratio of emitted light to incident light decreases in the direction of specular reflection, where the angle of emission is approximately equal to the angle of incidence of the illumination light source.

[0035] This is because, under conditions of specular reflection, the light absorption of the transparent ink layer 4 increases. On the other hand, the transparent ink layer 4 transmits most of the incident light in a direction where the angle of emergence relative to the angle of incidence of the illumination light source is not specular. Therefore, in this case, the incident light is hardly attenuated as it passes through the transparent ink layer 4, and the emitted light when reflected by the underlying glitter ink layer 5 or colored ink layer 3 becomes the emitted light from the transparent ink layer 4 almost as it is.

[0036] The printing method for forming the glitter ink layer 5, the colored ink layer 3, and the transparent ink layer 4 may be gravure printing, wet offset printing, dry offset printing, letterpress printing, waterless lithographic printing, flexographic printing, screen printing, intaglio printing, or the like, or may be inkjet printing or electrostatic printing. Also, melt transfer or sublimation transfer using an ink ribbon may be used.

[0037] The glitter ink layer 5 does not form any particular pattern, but is formed uniformly in a predetermined region on one surface of the substrate 2. The glitter ink layer 5 is formed, for example, as a solid color. Meanwhile, the colored ink layer 3 and the transparent ink layer 4 respectively constitute a first pattern 100 and a second pattern 200, which are predetermined pattern images, and are formed in a position superimposed on the glitter ink layer 5 on one surface of the substrate 2. As a result, although the appearance differs depending on the observation angle, a predetermined pattern image 300, which is a combination of the first pattern 100 and the second pattern 200, is formed on the above-mentioned one surface of the information recording medium 1.

[0038] In this embodiment, the first pattern 100 is a pattern consisting of the letters "ABC" as its smallest unit, which are continuously arranged in the horizontal direction, and this arrangement is further repeated in parallel in the vertical direction. Meanwhile, the second pattern 200 is a two-dimensional code. That is, the first pattern 100 is a pattern that can be read visually, while the second pattern 200 is a pattern that can be read by a general reading device equipped with a two-dimensional code reading function and converted into a unique, specific code. The specific code is a system of expression of information that is useful to the user and can be converted by a reading device or an authenticity determination device (described below).

[0039] It is sufficient that the first pattern 100 is such that the characters can be read visually or that it can be recognized as some kind of pattern, and it is preferable that this can moderately impair the visibility and readability of the second pattern 200. On the other hand, it is preferable that the transparent ink of the second pattern 200 is difficult to see visually, in order to increase the difficulty of reading.

[0040] The cell size refers to the length of one side of a rectangle called a cell, which is the smallest unit that makes up a two-dimensional code. A two-dimensional code forms a pattern that corresponds to a specific code as a whole by arranging these cells in a matrix of squares or not. Incidentally, if the two-dimensional code is QR Code (registered trademark) Model 2, version 25, and its overall size is 20 mm square, the corresponding cell size is approximately 0.17 mm, and if it is version 30, the corresponding cell size is approximately 0.15 mm.

[0041] When using an ink containing a silver-based glittering material, the glittering ink layer 5 is preferably formed with dots or lines having a dot area ratio of at least 80%. It is even more preferable to form 100% dots, i.e., solid dots. A dot area ratio of 80% or more improves the visibility of the first pattern 100 and the machine readability of the second pattern 200, while a dot area ratio of 100% further enhances these effects (visibility and machine readability). The dots of the glittering ink layer 5 are regular dots, such as regular dots, unlike irregular dots found in FM screen images. The dot area ratio is the percentage of the dot area per unit area in halftone dot gradation. An example of a method for calculating the dot area ratio will be described later.

[0042] The colored ink layer 3 constituting the first pattern 100 may be a white ink, a black ink, or a gray ink obtained by blending or superimposing these. Alternatively, it may be an ink obtained by blending or superimposing process color inks such as yellow (Y), magenta (M), and cyan (C) inks, other black inks, and special color inks, etc. The colored ink layer 3 is a layer composed of opaque, colorless, or chromatic inks, and the colored inks forming the colored ink layer 3 preferably have a dot area ratio of 35% to 55%, and more preferably 40% to 50%.

[0043] FIG. 18 shows a table 80 summarizing the merits and demerits of various performances for each colored ink dot area percentage. In table 80 of FIG. 18, the rows show the colored ink dot area percentages, which range from 25% to 60% in 5% increments. Table 80 of FIG. 18 also shows the columns show various performances, including machine readability of colored ink two-dimensional codes, machine readability of transparent ink two-dimensional codes, colored ink visibility, and copy protection. The intersections of the rows and columns represent evaluations, with the performance being rated on a three-point scale: ○, △, and ×. ○ indicates good, × indicates poor, and △ indicates intermediate results. According to table 80, within a range 81 where the dot area percentage is between 35% and 55%, there are no defects in any of the evaluations. Furthermore, within a range 82 where the dot area percentage is between 40% and 50%, the performance is rated even better. The best is around 45%, which means that all performance ratings are good. In addition, if the colored ink (first pattern 100) is designed not to be machine-readable (if it is used only for the camouflage function of second pattern 200), there is no defect as long as the dot area ratio is in the range of 30% to 55%.

[0044] Here, the dot area percentage of the colored ink was measured using the following two methods. (Method 1) Equipment: Portable spectrophotometer (eXact Advance) manufactured by X-rite Measurement lighting conditions: M1 (compliant with ISO 13655) Color calculation parameters: D50 / 2 Measure the area where the colored ink was placed on top of the glitter ink The colored ink was designated as C (cyan), and the cyan value was read from the CMYK color (K: black) being measured (measurement of dot %) → The above equipment was installed at the location where measurement was desired, density measurement was performed, and the measurement result was the dot %. Figure 18 shows the results obtained using Method 1.

[0045] (Method 2) Equipment: Microscope (Keyence MHX500F) Dot density is measured and calculated from the dot pitch and size (actual measurement) The printed matter is printed at a resolution of 150 lines and 2400 dpi In the case of Method 2, as shown in Figure 19, the dot area ratio can be calculated from the size of the dot 92 relative to the area of ​​a 150-line pitch 91 surrounded on all sides by lines 90a that are 150 lines on the printed matter 90, which is the measurement medium.

[0046] By having the dot area ratio of the colored inks in the former range, it is possible to increase the amount of reflected light that passes through the gaps between the dots of the colored inks and is reflected by the underlying glitter ink layer 5, relative to the amount of incident light from outside. This increases the contrast between the transparent ink layer 4 that constitutes the second pattern 200 under specified conditions and the underlying glitter ink layer 5 and colored ink layer 3, improving the readability of the second pattern 200 by a reading device. Furthermore, by having the dot area ratio of the colored inks in the latter range, the readability of the second pattern 200 is further improved, and stable readability is achieved that is less susceptible to the influence of individual differences in the illumination intensity and other characteristics of each model of reading device.

[0047] On the other hand, there are no particular restrictions on the two-dimensional code of the second pattern 200 shown in Fig. 1(a), but it is preferable to make the cell size as large as possible and the overall size of the two-dimensional code as small as possible. Incidentally, if the two-dimensional code is a QR Code (registered trademark) model 2 and its overall size is 12 mm square, it is preferable to set the version to 10 or less, and more preferably to set the version to 3 or less. This is to improve the readability of the second pattern 200.

[0048] Assume that second pattern 200 is a QR Code (registered trademark) of model 2. In this case, the outer contour of second pattern 200 is approximately square, and cut-out symbols 200p consisting of a small square and a slightly larger square outer frame surrounding the small square are placed at the three vertices. The cut-out symbols are also called finder patterns, and are used to determine the position and inclination of the pattern when reading the code with a reading device.

[0049] In this embodiment, the first pattern 100 is a visually readable pattern, and the second pattern 200 is a two-dimensional code. Therefore, only the second pattern 200 can be converted into a unique, specific code by a reading device. However, the first pattern 100 may be a random or meaningless pattern that cannot be visually read, or may be some kind of design that is intended solely for decorative purposes. This is because the first pattern 100 is sufficient as long as it has the minimum effect of camouflaging the presence of the second pattern 200.

[0050] Next, we will explain how the pattern image 300 formed on the information recording medium 1 appears as the observation angle changes. Figure 2(a) shows a situation in which the information recording medium 1 on which the pattern image 300 is formed is placed on a platform (not shown), and white light is emitted onto it from an illumination light source 21 that is positioned at an angle with respect to the normal direction to the main surface of the information recording medium 1. The light emitted from the illumination light source 21 has an emission angle α with respect to the normal direction to the main surface of the information recording medium 1.

[0051] In this case, when observed from viewpoint 22a at position P1, which is inclined at angle β1 smaller than angle α to the opposite side of illumination light source 21 with respect to the normal direction, the pattern image visible on information recording medium 1 is pattern image 300a shown in Fig. 2(b). In other words, only first pattern 100 can be clearly seen from viewpoint 22a at position P1, where the observation angle is β1.

[0052] As described above, the underlying glitter ink layer 5 diffusely reflects light regardless of the observation angle, and the first pattern 100 made of the colored ink layer 3 also tends to diffusely reflect light of a specific wavelength toward almost the entire area, although not as much as the glitter ink layer 5. Therefore, light incident at an incident angle α is also reflected at an exit angle β1, which is different from α. On the other hand, the second pattern 200 made of the transparent ink layer 4 transmits most of the incident light at positions that are not near the observation angle corresponding to the exit angle of regular reflection. Therefore, under these conditions, it is difficult to visually recognize the second pattern 200.

[0053] Furthermore, when observed from viewpoint 22b at position P2, which is tilted at angle β2, approximately the same as angle α, away from the illumination light source 21 relative to the normal direction, the pattern image visible on the information recording medium 1 is pattern image 300b shown in FIG. 2(c). That is, from viewpoint 22b at position P2, where the observation angle is β2, both the first pattern 100 and the second pattern 200 are visible, with the second pattern 200 being particularly visible. As described above, the first pattern 100, which is composed of the glitter ink layer 5 and the colored ink layer 3, exhibits diffuse reflection regardless of the observation angle. In contrast, the second pattern 200, which is composed of the transparent ink layer 4, exhibits a reduced ratio of reflected light to incident light near the observation angle corresponding to the emission angle of specular reflection, compared to other observation angles, allowing for sufficient contrast between the glitter ink layer 5 and the first pattern 100.

[0054] When observed from viewpoint 22c at position P3, which is tilted at angle β3, which is larger than angle α, toward the opposite side of illumination light source 21 with respect to the normal direction, the pattern image visible on information recording medium 1 is pattern image 300a shown in Fig. 2(b). In other words, the pattern image appears similar to that seen at viewpoint 22a at position P1, where the observation angle is β1. The reason for this is the same as when the observation angle is β1.

[0055] Assume that the pattern image 300b formed on the information recording medium 1 in Figure 2(c) is read by the reading device at viewpoint 22b at position P2. Here, of the light reflected from the information recording medium 1 and incident on the reading device, the reflectance of the portion of the glitter ink layer 5 underlying the pattern image 300b and the first pattern 100 to the white light of the original illumination light source 21 is defined as Re21 (%). Also, the reflectance of the light reflected from the second pattern 200 to the white light of the original illumination light source 21 is defined as Re22 (%). When the reflectance of the portion of the glitter ink layer 5 to the white light is defined as Re211 (%) and the reflectance of the light reflected from the first pattern 100 to the white light of the original illumination light source 21 is defined as Re212 (%), Re211 is usually greater than Re212. Re21 indicates the reflectance including both Re211 and Re212.

[0056] In this case, the threshold value for reflectance in the binarization process of the reading device is set to Re23, which is smaller than Re21 and larger than Re22, and pixels where light enters with a reflectance equal to or greater than this threshold are determined to be 1 or white, and pixels where light enters with a reflectance less than this threshold are determined to be 0 or black. Through this process, the reading device captures the portion of the glitter ink layer 5 that forms the background of the pattern image 300b and the portion of the first pattern 100 as 1 or white, and the portion of the second pattern 200 as 0 or black. This allows the second pattern 200 to be extracted with good contrast and successfully converted into a specific code.

[0057] When the colored ink forming the colored ink layer 3 has a dot area ratio of 35% or more and 55% or less, the glitter ink layer 5 is slightly exposed through the gaps between the dots of the first pattern 100 underlying the pattern image 300b. Therefore, there is little risk that a local decrease in reflectance due to the first pattern 100 will interfere with the reading of the second pattern 200. It has been explained that the pattern image 300 appears in two different ways, 300a and 300b, depending on the positional relationship between the illumination light source 21 and the observation angle, but these differences in appearance can be produced without changing the positional relationship between the illumination light source 21 and the observation angle.

[0058] For example, in Figure 2(a), observation is made from a fixed viewpoint 22b at position P2, which is tilted by angle β2, which is approximately the same as angle α. Then, the illumination light source 21 is turned off, or the illumination light source 21 is turned on with a significantly reduced light intensity. In this case, diffuse light is dominantly incident on the information recording medium 1, and strong parallel light is not incident, so most of the incident light passes through the transparent ink layer 4. As a result, the second pattern 200 is not visible, and only the glittering ink layer 5 and the first pattern 100 are visible due to the effect of diffuse reflection. In other words, the pattern image 300a in Figure 2(b) is visible.

[0059] On the other hand, when the illumination light source 21 is turned on with a sufficient amount of light under the above conditions, a relatively strong parallel light is incident on the information recording medium 1 at an incident angle α, and the second pattern 200 can be clearly seen together with the glittering ink layer 5 and the first pattern 100. In other words, the pattern image 300b in Figure 2(c) can be seen. At this time, most of the incident light is absorbed by the transparent ink layer 4, reducing the proportion of outgoing light.

[0060] As described above, by keeping the light intensity of the illumination light source 21 constant and changing the observation angle, two different appearances, namely, pattern images 300a and 300b, can be produced for the pattern image 300 on the information recording medium 1. Furthermore, the same appearance can also be produced by changing only the light intensity of the illumination light source 21 between an off state and an on state, or between a low-light-intensity on state and a high-light-intensity on state, without changing the positional relationship between the illumination light source 21 and the observation angle. The above explanation also applies when the illumination light source 21 and the observation angle are both positioned opposite the normal direction as described above, i.e., when angles α and β2 are both 0°, as shown in FIG. 2( a).

[0061] The transparent ink layer 4 constituting the second pattern 200 only needs to be transparent enough to satisfy the above-mentioned conditions depending on the observation angle. Specifically, assuming that the incident angle of the illumination light source and the observation angle are not conditions for specular reflection, the transmittance for visible light with a wavelength of 380 nm or more and 780 nm or less is preferably 50% or more, and more preferably 80% or more. A transmittance of 50% or more makes the first pattern 100 more visible from the outside, thereby improving the camouflage effect of the second pattern 200. Furthermore, a transmittance of 80% or more makes the second pattern 200 of the transparent ink layer 4 less visible to the naked eye, thereby improving security.

[0062] As a result, the first pattern 100 is easily visible on one side of the information recording medium 1, but the second pattern 200 is difficult to see unless the incident angle of the illumination light source and the observation angle are in a predetermined relationship. This makes it difficult for third parties to discover the existence of the second pattern 200, which contains information that can be converted into a specific code, thereby improving security. Furthermore, if the pattern image 300 on one side of the information recording medium 1 is copied using a copier, it is difficult to extract the second pattern 200, which is composed of the transparent ink layer 4, because the illumination light source of the copier differs from constant light irradiation from a fixed position. As a result, the contrast between the diffusely reflecting portion of the glitter ink layer 5 and the first pattern 100 makes it easy to extract only the first pattern 100. This has a deterrent effect, making it difficult to copy the information recording medium 1 using a copier, thereby improving security.

[0063] Furthermore, by turning on the illumination light source with a sufficient amount of light and positioning the reading device at an observation angle that satisfies the conditions for regular reflection of the incident light from the illumination light source, even a commercially available, inexpensive reading device that has the function of reading two-dimensional codes without any special functions can easily extract the second pattern 200 and decode the specific code.

[0064] Even in this case, when the illumination light source is turned off or turned on with reduced light intensity, the surrounding light is significantly affected by diffused light. As a result, with the reading device, only the first pattern 100 of the information recording medium 1 can be clearly seen, while the second pattern 200 becomes difficult to read. Therefore, unless the reading conditions are appropriate, the second pattern 200 cannot be read, which sufficiently improves the reliability of the authenticity determination and security of the information recording medium 1. Furthermore, by making the second pattern 200 smaller than the first pattern 100, when the first pattern 100 and the second pattern 200 are printed in an overlapping manner, they can be mechanically read without any problems even if their printing positions are slightly misaligned.

[0065] However, the second pattern 200 may be provided with approximately the same size as the first pattern 100. In other words, the second pattern 200 and the first pattern 100 may be provided so that their outer circumferential contours approximately coincide with each other. This is because, by doing so, the range in which the second pattern 200 is to be disposed can be easily estimated using the visually recognizable first pattern 100 as a guide, and alignment of the reading device can be simplified. Note that the second pattern 200 and the first pattern 100 may be provided so that their outer circumferential contours approximately coincide with each other in part, and the above-described effect can be obtained even in this case.

[0066] Next, the specular gloss of the information recording medium 1 having the glitter ink layer 5 was measured using Method 3 (60-degree specular gloss) of JIS Z8741. Measuring instrument (gloss meter): HORIBA IG-310 manufactured by HORIBA, Ltd. (measurement area: ellipse with diameter 12 mm and minor axis 6 mm) Measurement surface: surface layer, print size: 33 mm x 33 mm Conditions: incident angle 60° to receiving angle 60° Number of measurements: N: average of 5 The configuration of the information recording medium 1 and its measurement results (average value) are as follows: (Result 1) In the case of substrate 2 (paper substrate (white)) + glitter ink layer 5 (silver) + colored ink layer 3 + transparent ink layer 4, the specular gloss was 40 (37 to 42). (Result 2) In the case of substrate 2 (paper substrate (white)) + glitter ink layer 5 (silver) + transparent ink layer 4, the specular gloss was 46 (45 to 48).

[0067] The information recording medium 1 uses the contrast between light and dark areas (areas) to enable a reading device to read the two-dimensional code on the transparent ink layer 4. Therefore, if the glossiness of areas that should be bright is reduced by the colored ink layer 3, the readability of the two-dimensional code may be reduced or it may become completely unreadable. For this reason, it is desirable to use an information recording medium 1 with a specular glossiness that falls within the range of the above results.

[0068] (b) Configuration of the Reading Device for Information Recording Medium Next, the configuration of a reading device for reading information from the information recording medium of the present disclosure will be described. The reading device 30 has an illumination light source and a two-dimensional code reading function. As shown in FIG. 3(a), the reading device 30 has a reading unit 33 such as a camera, an illumination light source 21, an operation unit 35 for various operations, and a display unit 36 ​​which is a display screen for various displays. The reading device 30 also has a control unit 31 for issuing operational instructions to these units and inputting and outputting information, and a memory unit 32.

[0069] The reading unit 33 is a CCD camera or the like, with color CCD elements arranged pixel by pixel on a plane corresponding to the captured image. The reading unit 33 can output 256 levels of gray scale information (0 to 255) for each RGB color corresponding to the amount of incident light for each pixel to the image acquisition unit 44. The illumination light source 21 is an LED light or the like, the light intensity of which is adjustable. The display unit 36 ​​is an LCD display, an organic EL display, or the like, and the operation unit 35 is composed of a capacitive input touch panel that also serves as the display, allowing necessary operations to be performed by tracing the touch panel with a finger. The reading unit 33 may also be a black-and-white CCD camera or the like, capable of outputting 256 levels of gray scale information (0 to 255) for each pixel corresponding to the amount of incident light to the image acquisition unit 44.

[0070] The control unit 31 also includes a CPU or MPU and an input / output interface with each component, performs various calculations and judgments, and inputs and outputs information, including instructions, to each component. The control unit 31 also includes an illumination control unit 41 that controls the on / off state of the illumination light source 21 and the intensity of light, an image acquisition unit 44 that acquires images captured by the reading unit 33, and a code identification unit 45 that identifies a specific code from a two-dimensional code image acquired by the image acquisition unit 44. The memory unit 32 is a storage area, such as a semiconductor memory element, for storing programs, data, etc., necessary for the control unit 31 to execute various processes. The memory unit 32 includes a program storage unit 38. The program storage unit 38 stores programs for executing various functions of the control unit 31. The program for executing various functions of the control unit 31 may consist of a single program or multiple programs. Furthermore, the program may be incorporated into another program.

[0071] The reading device 30 may be composed of, for example, a personal computer or server having the functions of a control unit 31 and a memory unit 32, a reading unit 33 such as a CCD camera, an illumination light source 21, an operation unit 35, and a display unit 36. The respective devices may be connected to each other so as to be able to communicate with each other via a cable, or may be connected to each other so as to be able to communicate with each other via a network such as the Internet. The reading device 30 may also be a device in which the above functions are integrated, such as a smartphone. Note that a computer refers to an information processing device equipped with a control unit, a memory unit, etc., and the reading device 30 is an information processing device equipped with a control unit 31, a memory unit 32, etc., and is included in the concept of a computer.

[0072] (c) Method for Reading Information Recorded Medium Next, a method for reading information from the information recorded medium 1 of this embodiment will be described mainly with reference to Fig. 4. First, the reading device 30 activates the reading unit 33, such as a camera (step S401 in Fig. 4 (hereinafter, "step S" will be simply referred to as "S")). Next, the reading device 30 brings the pattern image 300 of the information recorded medium 1 into the field of view of the reading unit 33.

[0073] Next, the illumination control unit 41 of the reading device 30 turns on the illumination light source 21, enabling the reading unit 33 to capture not only the first pattern 100 but also the second pattern 200 from the pattern image 300 of the information recording medium 1. By turning on the illumination light source 21, strong parallel light from the illumination light source is incident on the information recording medium 1, and by orienting the reading device 30 at an appropriate observation angle, specularly reflected light from the information recording medium 1 can be made to enter the reading unit 33. At this time, the light reflected from the transparent ink layer 4 of the information recording medium 1 is reduced compared to the light reflected from the glitter ink layer 5 and the colored ink layer 3. Therefore, the contrast between the glitter ink layer 5 and the first pattern 100 of the colored ink layer 3 and the second pattern 200 of the transparent ink layer 4 is clear, with these as the background.

[0074] As a result, a large amount of reflected light is incident from the glitter ink layer 5, and a smaller amount of reflected light is incident from the colored ink layer 3. In other words, the reading unit 33 can properly photograph the second pattern 200. In this state, the image acquisition unit 44 acquires the image of the second pattern 200 from the reading unit 33, and the code identification unit 45 converts it into a specific code (S402).

[0075] In addition, when the reading device 30 is a smartphone, the illumination light source 21 and the reading unit 33 are often arranged in approximately the same position. In this case, the illumination light source 21 and the reading unit 33 may be arranged so as to face each other in the normal direction to the main surface of the information recording medium 1. In a general-purpose two-dimensional code reading application program that can be used on a smartphone or the like, a threshold value used in the image binarization process for extracting the two-dimensional code from the read image is usually automatically increased or decreased to optimize reading of the two-dimensional code. In this case, the threshold value is, for example, a brightness reference value that serves as a boundary for determining a background image as 1 and a two-dimensional code image as 0.

[0076] If the code identification unit 45 successfully converts the data into a specific code, a message to that effect is displayed on the display unit 36 ​​of the reading device 30 (S403 and S404). On the other hand, if the conversion into a specific code fails, a message to that effect is displayed on the display unit 36 ​​(S403 and S408). This completes the flow of the reading method in FIG. 4 . In the former case, another process can be continued based on the code identified from the second pattern 200. For example, the specific code can be considered as an authentication number for a financial transaction, and if it is authentic, the financial transaction can be enabled. On the other hand, in the latter case, it may be determined that the information recording medium 1 is not authentic, and the process may be terminated.

[0077] (d) Configuration of the Authentication Determination Device for Information Recording Medium Next, the configuration of the authentication determination device for determining the authenticity of the information recording medium 1 of this embodiment will be described. As shown in FIG. 3( b), the authenticity determination device 60 differs from the above-described reading device 30 in that the control unit 31a further includes an authenticity determination unit 46, and the memory unit 32a stores authenticity determination information 53 in addition to the program memory unit 38. The authenticity determination unit 46 has the function of determining whether the code converted and identified from the second pattern 200 by the code identification unit 45 in the above-described reading device 30 is authentic by comparing it with the authenticity determination information 53 in the memory unit 32a. In other words, the authenticity determination information 53 is comparison information for determining the authenticity of the information recording medium 1. Note that a computer refers to an information processing device equipped with a control unit, a storage device, etc., and the authenticity determination device 60 is an information processing device equipped with the control unit 31a, the memory unit 32a, etc., and is included in the concept of a computer.

[0078] (e) Method for Determining Authenticity of Information Recording Medium Next, the method for determining the authenticity of information on the information recording medium 1 of this embodiment will be described, following the steps of the reading method shown in FIG. 4 . After the code identification unit 45 has successfully converted the code into a specific code and a message to that effect is displayed on the display unit 36 ​​of the reading device 30 (S403 and S404), the authenticity determination unit 46 determines the authenticity of the code identified from the second pattern 200 by the code identification unit 45 (S405). If the code is determined to be authentic, a message to that effect is displayed (S406 and S407). If the code is determined to be inauthentic, a message to that effect is displayed (S406 and S409), and the process ends. Even if the second pattern 200 cannot be converted into a specific code (S403 and S408) and the process proceeds to process A, the process also ends via S409.

[0079] Here, the authenticity determination information 53 stored in the memory unit 32a may be, for example, a value that matches a code converted from the second pattern 200, or may be a value encrypted with a predetermined encryption key. In this case, the authenticity determination unit 46 may have the predetermined encryption key and determine the authenticity by calculating a value decrypted with its own encryption key from the value of the referenced authenticity determination information 53 and comparing this with the code identified from the second pattern 200. This reduces the risk that the authenticity determination information 53 will be illegally read or tampered with from outside.

[0080] The authenticity determination information 53 may be stored in a storage unit of a separate management server, rather than in the storage unit 32a of the authenticity determination device 60. In this case, it is preferable that the authenticity determination device 60 has a function of communicating with the management server via the Internet, a wide area communication network for mobile phones, or the like.

[0081] The reading device 30 and the authenticity determination device 60 correctly extract the required specific code from the information recording medium 1 and determine its authenticity. This allows the correct information to be identified from the information recording medium 1 and the procedure to proceed securely using this as a condition for financial transactions, and also makes it easy to detect counterfeiting or unauthorized use of the information recording medium.

[0082] The authenticity determination device 60 may be composed of, for example, a personal computer or server having the functions of the control unit 31a and the memory unit 32a, a CCD camera or the like serving as the reading unit 33, the illumination light source 21, an operation unit 35, and a display unit 36. The devices may be communicatively connected to each other via cables, or may be communicatively connected to each other via a network such as the Internet. In this case, the authenticity determination device 60 constitutes an authenticity determination system in which the devices are communicatively connected to each other. The authenticity determination device 60 may also be a device in which the above-mentioned functions are integrated, such as a smartphone.

[0083] 2. Second Embodiment Next, a second embodiment of the information recording medium of the present disclosure will be described. The layer structure of the information recording medium 1a according to the second embodiment shown in FIG. 5(a) is the same as that of the information recording medium 1 according to the first embodiment shown in FIG. 1(b). This also applies to the other embodiments and modifications described below, except for the twelfth and thirteenth embodiments. The information recording medium 1a has a pattern image 301 on one side of the substrate 2 so as to overlap the glittering ink layer 5. The pattern image 301 includes a first pattern 101 formed of a colored ink layer 3 and a second pattern 200 formed of a transparent ink layer 4.

[0084] The information recording medium 1a of the second embodiment differs from the first embodiment in that the first pattern 101 constituting the pattern image 301 is not a pattern composed of characters or the like, and the first pattern 101 and the second pattern 200 are both two-dimensional codes. That is, it is possible to read the first pattern 101 and the second pattern 200 separately and convert them into unique, specific codes using a general reading device equipped with a two-dimensional code reading function.

[0085] The transparent ink of the second pattern 200 is preferably difficult to see, and alignment when reading with a machine (for example, a camera) is performed while visually observing the highly visible first pattern 101. With this configuration, alignment can be easily performed while visually observing through a machine.

[0086] Furthermore, the colored ink layer 3 constituting the first pattern 101 may have the same configuration as that of the first embodiment, and the colored ink forming the colored ink layer 3 preferably has a dot area ratio of 35% to 55%, more preferably 40% to 50%. This is because even if the first pattern 101 is a two-dimensional code, the same effect as that of the first embodiment can be expected.

[0087] Assume that both the first pattern 101 and the second pattern 200 are QR Codes (registered trademark) of model 2. In this case, the outline of both patterns is approximately square, and cut-out symbols 101p and 200p, each consisting of a small square and a larger square outer frame surrounding the small square, are arranged at the three vertices. In particular, when conversion from the first pattern 101 to a specific code is required, it is preferable to arrange both patterns so that the cut-out symbol 101p of the first pattern 101 and the second pattern 200 do not overlap. This is because the readability of the first pattern 101 is improved.

[0088] Next, we will explain how the pattern image 301 formed on the information recording medium 1 appears depending on the observation angle. We will explain this situation assuming that the information recording medium 1a on which the pattern image 301 is formed is placed on a platform (not shown), and white light is emitted onto it from the illumination light source 21, which is positioned at an angle with respect to the normal direction to the main surface of the information recording medium 1a.

[0089] In this case, when observed from viewpoint 22a at position P1, which is tilted from the normal direction toward the opposite side of illumination light source 21 by angle β1 smaller than angle α, the pattern image visible on information recording medium 1a is pattern image 301a shown in FIG. 5B. That is, only first pattern 101 is clearly visible from viewpoint 22a at position P1, where the observation angle is β1. Furthermore, when observed from viewpoint 22b at position P2, which is tilted from the normal direction toward the opposite side of illumination light source 21 by angle β2, which is approximately the same as angle α, the pattern image visible on information recording medium 1a is pattern image 301b shown in FIG. 5C. That is, from viewpoint 22b at position P2, where the observation angle is β2, both first pattern 101 and second pattern 200 are clearly visible, with second pattern 200 being particularly clearly visible.

[0090] When observed from viewpoint 22c at position P3, which is tilted at angle β3, which is larger than angle α, toward the opposite side of illumination light source 21 with respect to the normal direction, the pattern image visible on information recording medium 1 is pattern image 301a shown in Fig. 5(b). In other words, the pattern image appears similar to that seen from viewpoint 22a at position P1, where the observation angle is β1.

[0091] Assume that the pattern image 301a formed on the information recording medium 1 in Figure 5(b) is read by a two-dimensional code reader at the viewpoint 22a at position P1 or the viewpoint 22c at position P3. Here, of the light reflected from the information recording medium 1 and incident on the reader, the reflectance of the light reflected from the glittering ink layer 5, which is the background for the pattern image 301a, relative to the white light of the original illumination light source 21 is set to Re211 (%). Also, the reflectance of the light reflected from the first pattern 101 relative to the white light of the original illumination light source 21 is set to Re212 (%). In other words, the same definitions are used as in the first embodiment.

[0092] At this time, the reading device performs a binarization process according to the amount of light incident on each pixel, which is a CCD element. The threshold value for reflectance is set to a first threshold value Re13 greater than Re212 and less than Re211, and pixels that receive light with a reflectance equal to or greater than this threshold are determined to be 1 or white, and pixels that receive light with a reflectance less than this threshold are determined to be 0 or black. By performing this process, the reading device captures the underlying glossy ink layer 5 of the pattern image 300a as 1 or white, and the first pattern 101 as 0 or black, thereby extracting the first pattern 101 with good contrast and successfully converting it into a specific code.

[0093] Similarly, suppose that the pattern image 301b formed on the information recording medium 1a in Figure 5(c) is read by the reading device from viewpoint 22b at position P2. Here, of the light reflected from the information recording medium 1a and incident on the reading device, the reflectance of the light reflected from the portion of the glitter ink layer 5 underlying the pattern image 301b and the first pattern 101 relative to the white light of the original illumination light source 21 is defined as Re21 (%), as described above. Re21 represents the reflectance including both Re211 and Re212 described above. Furthermore, the reflectance of the light reflected from the second pattern 200 relative to the white light of the original illumination light source 21 is defined as Re22 (%).

[0094] In this case, the reflectance threshold for the binarization process of the reading device is set to a second threshold Re23 that is smaller than Re21 and larger than Re22, and pixels that receive light with a reflectance equal to or greater than this threshold are determined to be 1 or white, and pixels that receive light with a reflectance less than this threshold are determined to be 0 or black. Through this process, the reading device captures the portion of the glitter ink layer 5 that forms the background of the pattern image 301b and the portion of the first pattern 101 as 1 or white, and the portion of the second pattern 200 as 0 or black. This allows the second pattern 200 to be extracted with good contrast and successfully converted into a specific code.

[0095] Although the glitter ink layer 5 is slightly exposed in the gaps of the first pattern 101 underlying the pattern image 301b, as described above, the cell size of the two-dimensional code of the first pattern 101 is sufficiently small, so there is little risk that the glitter ink layer 5 will interfere with the reading of the second pattern 200. It has been explained that the pattern image 301 appears in two different ways, 301a and 301b, depending on the positional relationship between the illumination light source 21 and the observation angle, but these differences in appearance can be produced without changing the positional relationship between the illumination light source 21 and the observation angle. This is the same as in the first embodiment.

[0096] As a result, on one side of the information recording medium 1a, the first pattern 101 is easily visible, but the second pattern 200 is difficult to see, making it difficult for third parties to discover the existence of the second pattern 200, which contains information that can be converted into a specific code, and improving security. Furthermore, when the pattern image 301 on one side of the information recording medium 1 is copied using a copier, it is difficult to extract the second pattern 200, which is made of the transparent ink layer 4, because the illumination light source of the copier is different from constant light irradiation from a fixed position. As a result, only the first pattern 101, which is made of the colored ink layer 3 with the diffusely reflective glitter ink layer 5 as an undercoat, becomes easily extracted. This has a deterrent effect on copying using a copier, making it difficult to duplicate the information recording medium 1a, thereby improving security.

[0097] In this embodiment, the first pattern 101 and the second pattern 200 constituting the pattern image 301 are both patterns that can be read by a general reading device equipped with a function for reading two-dimensional codes under predetermined conditions and that can be converted into a unique specific code. The first pattern 101 is provided solely for camouflage purposes, and the specific code converted from the first pattern 101 may be a meaningless dummy code. In this case, by reading the second pattern 200 under predetermined conditions as in the first embodiment, it is possible to convert it into a specific code or determine its authenticity.

[0098] However, the present embodiment is not limited to this. For example, the first pattern 101 constituting the pattern image 301 may be read by the reading device under a predetermined first condition, and the second pattern 200 constituting the pattern image 301 may be read by the reading device under a predetermined second condition. In this case, the first pattern 101 and the second pattern 200 may each be converted into a specific code, and if the respective codes match two types of authenticity determination information 53 stored in the memory unit 32a, the pattern image 301 may be determined to be authentic. In this case, the predetermined first condition may be a condition in which the illumination of the reading device is turned off, and the predetermined second condition may be a condition in which the illumination of the reading device is turned on.

[0099] 3. Third Embodiment Next, a third embodiment of the information recording medium of the present disclosure will be described. The information recording medium 1b according to the third embodiment shown in FIG. 6(a) has a pattern image 302 on one side of the substrate 2 so as to overlap the glitter ink layer 5. The pattern image 302 includes a first pattern 101 formed by the colored ink layer 3 and a second pattern 201 formed by the transparent ink layer 4. The second pattern 201 formed by the transparent ink layer 4 of the information recording medium 1b is composed of multiple partial patterns 201a, 201b, 201c, and 201d, which are separately arranged in four locations: the upper left, upper right, lower left, and lower right. This differs from the information recording mediums 1 and 1a of the first and second embodiments. The partial patterns are arranged in a matrix of two vertical rows and two horizontal rows.

[0100] In this embodiment, the four partial patterns constituting the second pattern 201 are all two-dimensional codes of the same pattern. That is, when a general reading device equipped with a two-dimensional code reading function can read each of the partial patterns constituting the first pattern 101 and the second pattern 201 separately, the reading device can convert each of the partial patterns into a unique, specific code. The partial patterns 201a, 201b, 201c, and 201d are each converted into the same code.

[0101] The four partial patterns are arranged so that they are spaced apart by a predetermined gap and face the same direction. That is, the cut-out symbols 201p of the multiple partial patterns are arranged so that they do not overlap each other, and the cut-out symbols 201p are arranged at the top left, top right, and bottom left of each partial pattern.

[0102] In this way, the information recording medium 1b of the third embodiment has all the configurations of the information recording mediums 1 and 1a of the first and second embodiments, but the second pattern 201 made of the transparent ink layer 4 is composed of a plurality of partial patterns arranged separately in four locations. Furthermore, each partial pattern is converted into the same code.

[0103] This configuration of the information recording medium 1b improves the quality of the information recording medium 1b and broadens its adaptability to different reading environments. Specifically, there may be manufacturing defects, such as a loss of a portion of the second pattern 201 formed by the transparent ink layer 4, or the illumination of the information recording medium 1b by the illumination light source may be too strong, causing halation in a portion of the second pattern 201. Even in such cases, if any one of the four partial patterns can be completely read, the correct specific code can be decoded. Therefore, accurate authentication can be performed while mitigating the reading environment conditions of the reading device.

[0104] 4. Fourth Embodiment Next, a fourth embodiment of the information recording medium of the present disclosure will be described. The configuration of an information recording medium 1c according to the fourth embodiment shown in FIG. 6(b) is substantially the same as that of the information recording medium 1b according to the third embodiment. The information recording medium 1c has a pattern image 303 on one side of the substrate 2 so as to overlap the glitter ink layer 5. The pattern image 303 includes a first pattern 101 formed by a colored ink layer 3 and a second pattern 202 formed by a transparent ink layer 4. The second pattern 202 formed by the transparent ink layer 4 of the information recording medium 1c is different from the third embodiment in that it is composed of different partial patterns, and each partial pattern can be converted into a different specific code.

[0105] (a) Structure of the Information Recording Medium The multiple partial patterns 202a, 202b, 202c, and 202d arranged separately in four locations that make up the second pattern 202 all have the same arrangement of cut-out symbols 202p, but are all two-dimensional codes with different patterns. Therefore, when read by a reading device, each partial pattern is converted into a different specific code. For example, the partial patterns 202a, 202b, 202c, and 202d can be converted into "XYZ67890," "ABC11111," "ABC22222," and "ABC33333," respectively. Incidentally, the first pattern 101 can be converted into "ABC12345."

[0106] With this configuration of the information recording medium 1c, four different types of information can be stored in the second pattern 202 of the information recording medium 1c, and by associating these types of information in some way, the security of reading the information recording medium can be further improved. For example, only the code converted from partial pattern 202a may be the genuine code, and the codes converted from the other partial patterns 202b, 202c, and 202d may all be dummy codes. Which of the four partial patterns is the genuine code may be set and stored in advance as application data in the reading device, or the code converted by reading the first pattern 101 may include the layout information and identifying information of the correct partial pattern.

[0107] (b) Characteristics of the Reading Device for the Information Recording Medium of the Fourth Embodiment Next, the configuration of a reading device 30a for reading information from the information recording medium 1c of this embodiment will be described, focusing on the differences from the above-mentioned reading device 30 (see FIG. 3A). As shown in FIG. 7, the reading device 30a differs from the reading device 30 in that it includes a storage unit 32b, and that the storage unit 32b stores first pattern position specifying information 51 and second pattern position specifying information 52 in addition to a program storage unit 38. The reading device 30a also differs from the reading device 30 in the following respects. That is, the control unit 31b includes a first pattern position specifying unit 42 that specifies the reading position and reading range of the first pattern 101 by referring to the first pattern position specifying information 51 in the storage unit 32b. Furthermore, the control unit 31b includes a second pattern position specifying unit 43 that specifies the reading position and reading range of the second pattern 202 by referring to the second pattern position specifying information 52.

[0108] Storage of the first pattern position specifying information 51 is optional and is used when the first pattern 101 of the information recording medium 1c is separated into multiple partial patterns, each of which can be converted into a different specific code. In this case, the first pattern position specifying information 51 includes location information for partial patterns having an authentic code. In this embodiment, since the first pattern 101 can be converted into a single code, this information is not necessary. Furthermore, the second pattern position specifying information 52 includes location information for partial patterns having an authentic code among the multiple partial patterns that make up the second pattern 202 of the information recording medium 1b. For example, this information indicates that the partial pattern 202a located in the upper left is authentic.

[0109] The reading device 30a may be composed of, for example, a personal computer or server having the functions of the control unit 31b and the storage unit 32b, a CCD camera or the like serving as the reading unit 33, the illumination light source 21, an operation unit 35, and a display unit 36. The respective devices may be connected to each other so as to be able to communicate with each other via cables, or may be connected to each other so as to be able to communicate with each other via a network such as the Internet. The reading device 30a may also be a device in which the above functions are integrated, such as a smartphone.

[0110] (c) Method for Reading Information Recording Medium Next, a method for reading information from the information recording medium 1c according to this embodiment will be described primarily with reference to FIGS. 8 and 9. First, the reading device 30a activates the reading unit 33, such as a camera (S421 in FIG. 8). Next, the reading device 30a brings the pattern image 303 of the information recording medium 1c into the field of view of the reading unit 33. Here, if first pattern position identification information 51 is stored in the memory unit 32b, the control unit 31b references this information and, using the first pattern position identification unit 42, identifies the position and range of the first pattern 101 in the pattern image 303 that the reading unit 33 needs to read (S422). In this embodiment, this operation is unnecessary because the first pattern 101 is a single two-dimensional code and the position and range of the first pattern 101 to be read can be identified by the cut-out symbol 101p.

[0111] Next, the illumination control unit 41 of the reading device 30a turns off the illumination light source 21, enabling the reading unit 33 to capture only the first pattern 101 from the pattern image 303 of the information recording medium 1c. By turning off the illumination light source 21, strong parallel light is not incident on the information recording medium 1c from a specific direction, and the information recording medium 1b receives predominantly diffused light overall. As a result, the reading unit 33 sees more light reflected from the glitter ink layer 5 of the information recording medium 1c than from the colored ink layer 3, creating a clear contrast between the glitter ink layer 5 and the first pattern 100 in the colored ink layer 3 against the background of the glitter ink layer 5. As a result, only the first pattern 101 can be captured satisfactorily. In this state, the image acquisition unit 44 acquires an image of the first pattern 100 from the reading unit 33, and the code identification unit 45 converts it into a specific code (S423).

[0112] The state in which the reading unit 33 can capture only the first pattern 101 from the pattern image 303 on the information recording medium 1c is not limited to when the illumination light source 21 is turned off. For example, it is also possible to capture the image of only the first pattern 101 from the pattern image 303 on the information recording medium 1c by turning on the illumination light source 21 and adjusting the light intensity to be very weak.

[0113] If the code identification unit 45 is successful in converting the code into a specific code, a message to that effect is displayed on the display unit 36 ​​of the reading device 30a (S424 and S425). On the other hand, if the conversion into a specific code is unsuccessful, a message to that effect is displayed on the display unit 36 ​​(S424 and S426). In the former case, the process continues to process B, which is a step of identifying the reading position and range of the second pattern 202 based on the code identified from the first pattern 101. On the other hand, in the latter case, the process continues to process C.

[0114] In process B, the second pattern position specifying unit 43 of the control unit 31b refers to second pattern position specifying information 52 stored in the storage unit 32b. Then, the second pattern position specifying unit 43 specifies the position and range that need to be read within the second pattern 202 read from the pattern image 303 by the reading unit 33, i.e., the position and range of the partial pattern that should be acquired by the image acquisition unit 44 (S441 in FIG. 9 ). In this embodiment, when four partial patterns 202a, 202b, 202c, and 202d are read as the second pattern 202, only the partial pattern 202a located in the upper left among them is specified as the partial pattern that should be acquired by the image acquisition unit 44.

[0115] Next, the illumination control unit 41 of the reading device 30a turns on the illumination light source 21, enabling the reading unit 33 to capture only the second pattern 202 from the pattern image 303 of the information recording medium 1c. By turning on the illumination light source 21, strong parallel light from the illumination light source is incident on the information recording medium 1c, and by orienting the reading device 30a at an appropriate observation angle, specularly reflected light from the information recording medium 1c can be made to enter the reading unit 33. At this time, the light reflected by the transparent ink layer 4 of the information recording medium 1c is reduced compared to the light reflected by the glitter ink layer 5 and the colored ink layer 3. As a result, the contrast between the glitter ink layer 5 and the first pattern 101 of the colored ink layer 3 and the second pattern 202 of the transparent ink layer 4 is clear, with these as the background.

[0116] As a result, a large amount of reflected light is incident from the glitter ink layer 5 and the colored ink layer 3, and a smaller amount of reflected light is incident from the transparent ink layer 4. In other words, the reading unit 33 can properly photograph the second pattern 202. In this state, the image acquisition unit 44 acquires an image of the partial pattern 202a of the second pattern 202 from the reading unit 33, and the code identification unit 45 converts it into a specific code (S442).

[0117] If the code identification unit 45 succeeds in converting the code into a specific code, a message to that effect is displayed on the display unit 36 ​​of the reading device 30a (S443 and S444). On the other hand, if the conversion into a specific code fails, a message to that effect is displayed on the display unit 36 ​​(S443 and S445). In the former case, the user can continue another process as described above based on the code identified from the partial pattern 202a of the second pattern 202.

[0118] (d) Configuration of the Authenticity Determination Device for Information Recording Medium Next, the configuration of an authenticity determination device 60a for determining the authenticity of information on the information recording medium 1b of this embodiment will be described, focusing on differences from the above-described authenticity determination device 60. As shown in FIG. 10 , the authenticity determination device 60a differs from the above-described authenticity determination device 60 in that it includes a memory unit 32c, and the memory unit 32c stores first pattern position identification information 51 and second pattern position identification information 52 in addition to the program memory unit 38 and authenticity determination information 53. Furthermore, the authenticity determination device 60a includes a control unit 31c that includes a first pattern position identification unit 42 that identifies the reading position and reading range of the first pattern 101 by referring to the first pattern position identification information 51 stored in the memory unit 32c. Furthermore, the control unit 31c includes a second pattern position identification unit 43 that identifies the reading position and reading range of the second pattern 202 by referring to the second pattern position identification information 52. The storage unit 32c stores authenticity determination information 53 as comparison information for determining the authenticity of the information recording medium 1b.

[0119] The authenticity determination device 60a may be composed of, for example, a personal computer or server having the functions of the control unit 31c and the memory unit 32c, a CCD camera or the like serving as the reading unit 33, the illumination light source 21, an operation unit 35, and a display unit 36. The devices may be connected to each other via cables so as to be able to communicate with each other, or may be connected to each other via a network such as the Internet so as to be able to communicate with each other. In this case, the authenticity determination device 60a constitutes an authenticity determination system in which the devices are connected to each other so as to be able to communicate with each other. The authenticity determination device 60a may also be a device in which the above-mentioned functions are integrated, such as a smartphone.

[0120] (e) Method for Determining Authenticity of Information Recording Medium Next, a method for determining the authenticity of information on the information recording medium 1c of this embodiment will be described mainly with reference to FIGS. 8 and 11. First, as described above, the authenticity determination device 60a performs the steps from starting the reading unit 33 (S421 in FIG. 8) to identifying the code by reading the first pattern 101 (S424), and displays the result (S425). This is the same as the method for identifying the code in the first pattern 101 by the reading device 30a. Next, the authenticity determination device 60a performs steps S461 to S464 shown in FIG. 11, which correspond to steps S441 to S444 in FIG. 9, which are the processing for the reading device 30a shown in FIG. 9.

[0121] Thereafter, the authenticity determination unit 46 determines the authenticity of the code identified from the partial pattern 202a by the code identification unit 45 (S466). If it is determined that the code is authentic, a message to that effect is displayed (S467). If it is determined that the code is not authentic, a message to that effect is displayed (S469), and the process ends. If the first pattern 101 cannot be converted into an identified code (S424 and S426 in FIG. 8 ) and the process cannot proceed to the code identification step for the second pattern 202, the process also ends via S469.

[0122] In the information recording medium 1c of the fourth embodiment, the first pattern 101 formed by the colored ink layer 3 can be read so as to be converted into a specific code. The second pattern 202 formed by the transparent ink layer 4 is composed of four partial patterns 202a, 202b, 202c, and 202d, each of which can be read so as to be converted into a specific code. Furthermore, at least one of these partial patterns can be converted into a code different from the others. Here, the first pattern 101 can be converted into a first specific code, and the specific partial pattern 202a can be converted into a second specific code. The first specific code includes information regarding the position and range of the specific partial pattern 202a in the second pattern 202 that should identify the code.

[0123] Therefore, a first specific code is first extracted from the reading of the first pattern 100, and based on this, the position and range of the specific partial pattern 202a to be read in the second pattern 202 is identified, and a second specific code can be extracted from the specific partial pattern 202a. The second specific code may be any one of the partial patterns 202a to 202d, or may be a combination of codes read from any two or more partial patterns.

[0124] Because information recording medium 1c has such a configuration, it is difficult to correctly read first pattern 101 and second pattern 202 separately. Furthermore, even if a general-purpose reading device can read all four partial patterns that make up first pattern 101 and second pattern 202, it is difficult to determine which of the codes identified from these patterns represents the authenticity of information recording medium 1b. This allows information recording medium 1c to further improve security.

[0125] 5. Fifth Embodiment Next, a fifth embodiment of the information recording medium of the present disclosure will be described. An information recording medium 1d according to the fifth embodiment shown in FIG. 12(a) has a pattern image 304 on one side of a substrate 2 so as to overlap with a glittering ink layer 5. The pattern image 304 includes a first pattern 101 formed by a colored ink layer 3 and a second pattern 203 formed by a transparent ink layer 4. The configuration of the information recording medium 1d is substantially identical to the first pattern 101 and the information recording medium 1b according to the third embodiment, except that the orientation of the multiple partial patterns arranged separately in four locations in the second pattern 203 formed by the transparent ink layer 4 differs from that of the second pattern 201.

[0126] That is, the plurality of partial patterns 203a, 203b, 203c, and 203d arranged separately in four locations that make up the second pattern 203 are all two-dimensional codes of the same pattern. However, when the information recording medium 1d is viewed in plan from the above-mentioned one surface, the partial pattern 203b is arranged so that its orientation is rotated 90° clockwise from the partial pattern 202a.

[0127] Similarly, partial pattern 203c is arranged so that its orientation is rotated 90° counterclockwise from partial pattern 203a. Furthermore, partial pattern 203d is arranged so that its orientation is rotated 180° clockwise or counterclockwise from partial pattern 203a. Therefore, partial pattern 203a is arranged so that its cut-out symbols 203p are at the top left, top right, and bottom left of partial pattern 203a, and partial pattern 203b is arranged so that its cut-out symbols 203p are at the top left, top right, and bottom right of partial pattern 203a.

[0128] Further, partial pattern 203c is arranged so that its cut-out symbols 202p are at the top left, bottom left and bottom right, and partial pattern 203d is arranged so that its cut-out symbols 203p are at the top right, bottom left and bottom right.

[0129] In other words, the second pattern 203 of the information recording medium 1d is made up of a plurality of partial patterns, each of which has one or more cut-out symbols 203p, and all of the cut-out symbols 203p are arranged at the ends so as to face outward from the second pattern 203. Conversely, in each partial pattern, the cut-out symbols 203p are arranged so as not to lean toward the center of the second pattern 203.

[0130] In this embodiment, each partial pattern has three cut-out symbols 203p, but the present invention can also be applied to a case where there is only one cut-out symbol. In this case, the partial patterns are arranged so that the cut-out symbol of the upper left partial pattern is placed at the upper left, and the cut-out symbols of the upper right, lower left, and lower right partial patterns are placed at the upper right, lower left, and lower right, respectively.

[0131] The information recording medium 1d having such a configuration improves the quality of the information recording medium 1d and expands its adaptability to various reading environments. That is, depending on the adjustment of the illumination light source, the information recording medium 1d may be illuminated too strongly, causing significant halation (a phenomenon in which areas hit by strong light appear white and blurred) near the center of the second pattern 203. In this case, when each partial pattern constituting the second pattern 203 is read by a reading device, a portion of the partial pattern near the center of the second pattern 203 cannot be read.

[0132] However, since the cut-out symbol 203p, which serves as the reference for detecting the position of the partial pattern, is arranged along the outer periphery of the second pattern 203, the possibility of the reading device making a reading error when detecting the position of the partial pattern can be reduced.

[0133] On the other hand, two-dimensional codes have a certain degree of redundancy in their information, so even if the area other than the extracted symbol is partially lost, the code can often be restored using an error correction function. Therefore, with the information recording medium 1d of this embodiment, partial patterns can be read well even in a somewhat poor reading environment.

[0134] In the information recording medium 1d, the first pattern 101 may be convertible into a specific code, and some or all of the four partial patterns 203a, 203b, 203c, and 203d constituting the second pattern 203 may be convertible into different specific codes. In this case, the information recording medium combines the functions and effects of the present embodiment and the fourth embodiment, and the reading devices 30, 30a and the authenticity determining devices 60, 60a relating to such information recording mediums may also be applied.

[0135] 6. Sixth Embodiment Next, a sixth embodiment of the information recording medium of the present disclosure will be described. An information recording medium 1e according to the sixth embodiment shown in FIG. 12(b) has a pattern image 305 on one side of the substrate 2 so as to overlap with the glitter ink layer 5. The pattern image 305 includes a first pattern 101 formed by the colored ink layer 3 and a second pattern 204 formed by the transparent ink layer 4. The configuration of the information recording medium 1e is similar to that of the information recording medium 1d according to the fifth embodiment, except that the second pattern 204 formed by the transparent ink layer 4 has multiple partial patterns arranged separately in nine locations instead of four locations.

[0136] That is, the multiple partial patterns 204a, 204b, 204c, 204d, 204e, 204f, 204g, 204h, and 204i, which are arranged separately in nine locations constituting the second pattern 204, are all two-dimensional codes of the same pattern. They are arranged in a matrix of three columns and three rows. When the information recording medium 1e is viewed in plan from the above-mentioned one surface, partial patterns 204a, 204c, 204g, and 204i are arranged at the upper left, upper right, lower left, and lower right corners of the approximately square second pattern 204. Furthermore, partial patterns 204b, 204d, 204f, and 204h are arranged between partial patterns 204a and 204c, between 204a and 204g, between 204c and 204i, and between 204g and 204i, respectively.

[0137] Each partial pattern has three cut-out symbols 204p at each corner. Of these, partial patterns 204a, 204c, 204g, and 204i, which are arranged at the four corners of second pattern 204, are arranged so that the three cut-out symbols 204p follow the outer periphery of second pattern 204.

[0138] The other partial patterns 204b, 204d, 204e, 204f, and 204h are arranged in the same orientation as the partial pattern 204a, with the cut-out symbols 204p of each partial pattern being in the upper left, upper right, and lower left. However, the partial patterns arranged in locations other than the corners of the second pattern 204 may be arranged in any orientation.

[0139] The same can be done even if each partial pattern has only one cut-out symbol. Furthermore, the number of partial patterns included in second pattern 204 is not limited to nine, but may be increased arbitrarily to 16, 25, etc., and the number of columns and rows may be different.

[0140] In this way, in the information recording medium 1e of the sixth embodiment, of the partial patterns of the second pattern 204, the cut-out symbols 204p of the partial patterns arranged at the four corners of the second pattern 204 are arranged at the end so as to follow the outer periphery of the second pattern 204. By configuring the information recording medium 1e in this way, the quality of the information recording medium 1e is further improved and the adaptability to the reading environment can be further expanded.

[0141] 7. Seventh Embodiment Next, a seventh embodiment of the information recording medium of the present disclosure will be described. The information recording medium 1f according to the seventh embodiment shown in FIG. 13 includes a pattern image 306 on one side of the substrate 2 so as to overlap the glitter ink layer 5. The pattern image 306 includes a first pattern 101 formed by a colored ink layer 3 and a second pattern 205 formed by a transparent ink layer 4. The configuration of the information recording medium 1f is similar to that of the information recording medium 1e according to the sixth embodiment. The second pattern 205 formed by the transparent ink layer 4 includes partial patterns arranged at its four corners. The second pattern 205 is sandwiched between these partial patterns (first and second partial patterns) and includes a total of nine partial patterns, including four partial patterns that share the cut-out symbol 205p and a partial pattern (third partial pattern) arranged in the center.

[0142] When the information recording medium 1f is viewed in plan from the aforementioned one surface, partial patterns 205a, 205c, 205g, and 205i are arranged at the upper left, upper right, lower left, and lower right corners of the substantially square second pattern 205. Furthermore, dummy patterns that cannot be converted into a specific code or that are not intended for conversion are embedded between partial patterns 205a and 205c, between 205a and 205g, between 205c and 205i, and between 205g and 205i. These dummy patterns share the cut-out symbols 205p of the partial patterns arranged to the left, right, or above and below them, thereby forming dummy partial patterns that appear to be two-dimensional codes.

[0143] For example, dummy partial patterns 205b, 205d, 205f, and 205h are formed between partial patterns 205a and 205c, between 205a and 205g, between 205c and 205i, and between 205g and 205i. A dummy pattern is also embedded in the center surrounded by partial patterns 205a, 205c, 205g, and 205i, forming dummy partial pattern 205e. Of partial patterns 205a, 205c, 205g, and 205i of second pattern 205, 205c, 205g, and 205i can be converted into the same specific code, and 205a can be converted into a different specific code.

[0144] In this embodiment, the second pattern 205 of the information recording medium 1f appears to include nine partial patterns. However, in reality, only the partial patterns 205a, 205c, 205g, and 205i located at the four corners can be converted into a specific code as a two-dimensional code, and the rest are merely dummy partial patterns that cannot be converted into a specific code. Furthermore, the four partial patterns include patterns that can be converted into different specific codes, and for example, only partial pattern 205a can be converted into a genuine specific code.

[0145] To create the print data for the second pattern 205, first, a dummy pattern that includes all the components other than the cut-out symbols of the dummy partial patterns 205b, 205d, 205e, 205f, and 205h is created and laid out in a predetermined area. Next, a pattern including the cut-out symbols of the partial patterns 205a, 205c, 205g, and 205i is overwritten onto the dummy pattern. In other words, when a partial pattern overlaps with a dummy pattern, the former data is used preferentially. Creating the print data for the second pattern 205 in this manner ensures that the partial patterns 205a, 205c, 205g, and 205i can be read reliably.

[0146] As described above, in the information recording medium 1f of the seventh embodiment, each partial pattern of the second pattern 205 is divided into partial patterns that can be correctly converted into a specific code and dummy partial patterns that cannot be converted into a specific code. Therefore, even if a pattern image 306 of the second pattern 205 can be photographed, it is difficult to separate the correct patterns from the dummy patterns. Furthermore, even if multiple partial patterns that can be correctly converted into codes can be identified, it is difficult to identify which of them can be converted into a genuine code.

[0147] The information recording medium 1f of this embodiment may be modified, like the information recording medium 1e of the sixth embodiment, so that the cut-out symbols 205p of the partial patterns arranged at the four corners of the second pattern 205 are arranged at the ends along the outer periphery of the second pattern 205. Alternatively, the partial patterns arranged at the four corners of the second pattern 205 may all be the same pattern, or may all be different patterns. Needless to say, the above-mentioned reading devices 30, 30a and authenticity determination devices 60, 60a can also be applied to the information recording medium 1f.

[0148] 8. Eighth Embodiment Next, an eighth embodiment of the information recording medium of the present disclosure will be described. The information recording medium 1g according to the eighth embodiment shown in FIG. 14 includes a pattern image 308 on one side of the substrate 2, superimposed on the glitter ink layer 5. The pattern image 308 includes a first pattern 102 formed by the colored ink layer 3 and a second pattern 208 formed by the transparent ink layer 4. The configuration of the information recording medium 1g is similar to that of the information recording medium 1f according to the seventh embodiment. The second pattern 208 formed by the transparent ink layer 4 appears to be a two-dimensional code consisting of multiple partial patterns and dummy partial patterns arranged in a matrix of three columns and five columns. For example, the top row includes dummy partial patterns 208a, 208b, 208c, 208d, and 208e, arranged in this order from left to right.

[0149] Here, each partial pattern and dummy partial pattern has three cutout symbols, but horizontally adjacent partial patterns and dummy partial patterns share their respective cutout symbol 208p. Furthermore, only non-adjacent partial patterns 208b and 208d can be converted into a specific code, while dummy partial patterns 208a, 208c, and 208e are meaningless patterns other than cutout symbol 208p and cannot be converted into a specific code. The same applies to dummy partial patterns 208f, 208g, 208h, 208i, and 208j, which are arranged in order from left to right in the second row of second pattern 208. The same applies to dummy partial patterns 208k, 208l, 208m, 208n, and 208o, which are arranged in order from left to right in the third row.

[0150] In this embodiment, all partial patterns 208b, 208d, 208g, 208i, 208l, and 208n except for 208b are identical, with only 208b being a different pattern. Thus, in this embodiment, the second pattern 208 on the information recording medium 1g appears to include 15 partial patterns. However, in reality, only the patterns in the second and fourth columns from the left are partial patterns that can be converted into a specific code, and the rest are meaningless dummy patterns. Furthermore, by making some or all of the six partial patterns that can be converted into a specific code into patterns that can be converted into a different code, it is possible to extract only the genuine code and make it even more difficult to correctly read it. For example, in this embodiment, only partial pattern 208b can be converted into the genuine code.

[0151] However, the multiple partial patterns other than the dummy partial pattern may all be the same pattern. In this way, it is difficult to extract a partial pattern that can be converted into a genuine code, but if any of the multiple partial patterns is read correctly, conversion into a specific code is possible. This reduces the performance of the reading device, thereby increasing operational convenience. Note that, as an example of a dummy partial pattern, it is possible to consider having a defect in the cut-out pattern. If the cut-out pattern has a defect, the dummy partial pattern cannot be identified by the reading device.

[0152] 9. Ninth and Tenth Embodiments Up to now, embodiments have been mainly described in which the first pattern and the second pattern are both two-dimensional codes. However, the first pattern and the second pattern of the information recording medium according to the present disclosure are not limited to two-dimensional codes, and any information recording medium in which at least the second pattern contains information that can be converted into a specific code by a reading device is also applicable. As examples of these, a ninth embodiment in which the first pattern and the second pattern are barcodes and a tenth embodiment in which the first pattern and the second pattern are alphanumeric characters will be briefly described.

[0153] The information recording medium 1h according to the ninth embodiment shown in FIG. 15(a) has a pattern image 307 on one side of the substrate 2 so as to overlap the glitter ink layer 5. The pattern image 307 includes a first pattern 103 formed by a colored ink layer 3 and a second pattern 206 formed by a transparent ink layer 4. The information recording medium 1h is configured such that the first pattern 103 is a horizontally elongated barcode arranged continuously in the vertical direction, so as to reduce the exposed portion of the surface of the underlying substrate 2. The second pattern 206 is also a horizontally elongated barcode arranged as two partial patterns 206a and 206b, one above the other, so as to overlap the first pattern 103. Both the first pattern 106 and the second pattern 206 are CODE39 barcodes.

[0154] Similarly, the information recording medium 1i according to the tenth embodiment shown in Figure 15(b) has a pattern image 309 on one side of the substrate 2 so as to overlap the glitter ink layer 5. The pattern image 309 includes a first pattern 104 formed by the colored ink layer 3 and a second pattern 207 formed by the transparent ink layer 4. The information recording medium 1i is configured such that the first pattern 104 is a pattern in which "ABC12345," a combination of alphanumeric characters written horizontally, is continuously combined in the horizontal and vertical directions, and is configured so that the exposed portion of the surface of the underlying substrate 2 is reduced.

[0155] Also, superimposed on this is second pattern 207, which is composed of partial patterns 207a and 207b, each of which is a combination of alphanumeric characters written horizontally, and is arranged in two locations, one above the other, with "XYZ67890." Both first pattern 107 and second pattern 207 are created using the Century font, but may be created using other fonts or OCR characters. Such information recording media 1h and 1i can also achieve the same functions and effects as those described in the first and other embodiments.

[0156] 10. Eleventh Embodiment Next, as an eleventh embodiment of the present disclosure, a printed matter including an information recording medium will be described. A printed matter including an information recording medium is, for example, a ticket, admission ticket, card, or the like for a movie, concert, or amusement park to which the information recording medium is attached. A printed matter including an information recording medium has monetary value in itself, but a copy of the printed matter, such as a color copy, naturally has no monetary value. An example of a printed matter including an information recording medium is printed matter 10, which is an admission ticket, as shown in FIG. 16( a). The printed matter 10 includes a sheet 11 and the information recording medium 1 of the first embodiment, in which a portion of the sheet 11 is considered to be the base material 2. The sheet 11 also has a printed portion 12 formed thereon, on which is printed information indicating the ticket type, the purchaser, a serial number, and the like.

[0157] Here, the paper 11 is a substrate that serves as the base of the printed matter 10, and is typically white paper, but the paper may be high-quality paper or coated paper, or may be a plastic other than paper. Alternatively, the paper may be a mixed material or laminated material of paper and plastic. In any case, the paper 11 may be any material that can support the information recording medium 1 and carry various printed designs, etc., indicating the ticket type, etc.

[0158] The layer structure of the printed matter 10 including the information recording medium 1 is as shown in the cross-sectional view of Figure 16(b). Figure 16(b) is a cross-sectional view of the printed matter 10 of Figure 16(a) cut along line A-A, which passes through approximately the center of the information recording medium 1 in the vertical direction, viewed from below. The information recording medium 1 is formed on one surface of the paper 11 of the printed matter 10, with the paper 11 serving as the substrate 2, and from the side closest to the surface of the paper 11, a glitter ink layer 5, a colored ink layer 3, and a transparent ink layer 4 are layered in this order. The colored ink layer 3 and the transparent ink layer 4 respectively constitute the first pattern 100 and the second pattern 200 as described above.

[0159] Printed matter including the information recording medium is particularly difficult to counterfeit or use fraudulently, particularly by copying using a copier. Furthermore, compared to holograms with equivalent anti-counterfeiting effects, the material and processing costs are low and the information recording medium is easy to deploy. Furthermore, specific codes can be easily read and their authenticity determined using a general-purpose two-dimensional code reader while maintaining high security, improving convenience. Printed matter including the information recording medium of this embodiment can also be applied by replacing it with the information recording medium of each embodiment other than the first embodiment or their modified examples.

[0160] Note that the first pattern of the information recording medium described in the first embodiment is easily visible, but the second pattern is difficult to see, making it difficult for a third party to know of the existence of the second pattern containing information that can be converted into a specific code, thereby enhancing security, which is common to all of the second to eleventh embodiments. Furthermore, when the pattern image of the information recording medium is copied using a copier, it is difficult to extract the second pattern made up of a transparent ink layer, and only the first pattern made up of a colored ink layer that is prone to diffuse reflection is easily extracted, so similarly, there is an effect of deterring copying by a copier.

[0161] 11. Twelfth Embodiment Up to this point, we have described an information recording medium in which a glitter ink layer 5, a colored ink layer 3, and a transparent ink layer 4 are laminated in this order on a substrate 2. However, the spirit of the present invention is not limited to this embodiment. As an example of another embodiment, we will describe a twelfth embodiment in which a first pattern and a second pattern are combined with basic patterns that are each part of a separate code, and the resulting code as a whole can be read and its authenticity determined as a specific code.

[0162] The information recording medium 1n according to the twelfth embodiment shown in FIG. 17(a) has a first region and a second region on one side of a substrate 2, and the entire region constitutes a pattern image 311. In the first region, a basic pattern 511 is formed on one side of the substrate 2 using, for example, a black colored ink. The basic pattern 511 as a whole constitutes part of, for example, a two-dimensional code that can be read as a specific code. On the other hand, in the second region, a glitter ink layer 5 is formed on almost the entire surface of one side of the substrate 2, and a first pattern 111 is formed on top of it using a colored ink layer 3 of, for example, blue or red, different from the first region. The conditions for the glitter ink layer 5 and the colored ink layer 3 in this case are the same as those described in the first embodiment, for example.

[0163] Although the first pattern 111 cannot be read as a specific code by itself, by reading it together with the basic pattern 511, the entire pattern can be read as a specific code. The basic pattern 511 and the first pattern 111 as a whole constitute, for example, a two-dimensional code. Note that in the first region, the basic pattern 511 is formed directly on the substrate 2 using colored ink or the like, but similar to the second region, a glitter ink layer 5 may be formed on one side of the substrate 2, and the basic pattern 511 may be formed on top of that using colored ink such as black.

[0164] On the other hand, another information recording medium 1p according to the twelfth embodiment shown in FIG. 17(b) has a third region and a fourth region on one side of the substrate 2, and the entire region constitutes a pattern image 312. In the third region, a basic pattern 512 is formed on one side of the substrate 2 using, for example, black ink. The basic pattern 512 has the same configuration as that of the information recording medium 1n described above. In addition, in the fourth region, a glitter ink layer 5 is formed on one side of the substrate 2, and a second pattern 212 is formed on the upper layer using a transparent ink layer 4 without an intervening colored ink layer or the like. The conditions for the glitter ink layer 5, colored ink layer 3, and transparent ink layer 4 in this case are the same as those described in the first embodiment, for example.

[0165] The second pattern 212 cannot be read as a specific code by itself, but can be read as a specific code as a whole by reading it together with the basic pattern 512. The basic pattern 512 and the second pattern 212 as a whole constitute, for example, a two-dimensional code.

[0166] An example of the operation of reading and authenticity determination using these two types of information recording media 1n and 1p can be performed as follows. First, as in the fourth embodiment, the illumination light source of the reading device is turned off and the pattern image 311 of the information recording medium 1n is read. At this time, the incidence angle and observation angle of the illumination light source for the basic pattern 511 of the first region and the first pattern 111 of the second region correspond to the conditions for diffuse reflection. Therefore, each can obtain good contrast with the underlying substrate 2 and the glitter ink layer 5, and the two patterns can be read as a single specific code combined.

[0167] Next, the illumination light source of the reading device is turned on, and the pattern image 312 on the information recording medium 1p is read. At this time, the incident angle and observation angle of the illumination light source for the basic pattern 512 in the third region and the second pattern 212 in the fourth region correspond to the conditions for specular reflection. Therefore, each pattern can obtain good contrast with the underlying substrate 2 and the glitter ink layer 5, and the two patterns can be read as a single specific code combined.

[0168] As described above, by reading both information recording medium 1n and information recording medium 1p while changing the illumination light source conditions of the reading device, it is possible to determine whether information recording medium 1n and information recording medium 1p are genuine only if the specific codes read from each are correct. Alternatively, it is also possible to input both the code obtained from information recording medium 1n and the code obtained from information recording medium 1p, and only then can the corresponding necessary information be obtained. By using these two types of information recording mediums 1n and 1p, it is possible to construct an authentication determination system that cannot correctly read codes unless the illumination light source conditions of the reading device are appropriately changed. In other words, since information recording medium 1p cannot be read normally when the incident angle and observation angle of the illumination light source are such that diffuse reflection occurs, the reliability of authentication determination is improved.

[0169] 12. Thirteenth Embodiment Next, a thirteenth embodiment of the information recording medium of the present disclosure will be described. Fig. 20(a) is a plan view illustrating an information recording medium 1q according to the thirteenth embodiment, and Fig. 20(b) is a side view thereof.

[0170] The information recording medium 1q has a pattern image 313 on one side of the substrate 2, covering the glitter ink layer 5-2. The pattern image 313 includes a first pattern 113 made of a colored ink layer 3 and a second pattern 200 made of a transparent ink layer 4. When the information recording medium 1q is viewed from above in the thickness direction, the entire second pattern 200 made of the transparent ink layer 4 overlaps the area where the glitter ink layer 5-2 is formed. Also, unlike the information recording medium 1 of the first embodiment (see FIG. 1), the information recording medium 1q has a first pattern 113 made of a colored ink layer 3 that partially overlaps the area where the glitter ink layer 5-2 is formed, and the entire first pattern 113 extends beyond the area where the glitter ink layer 5-2 is formed.

[0171] In this way, the information recording medium 1q may have the first pattern 113 formed by the colored ink layer 3 protruding from the glittering ink layer 5-2. In other words, in this embodiment, the first pattern 113 is a pattern that can be read visually, and the second pattern 200 is a two-dimensional code. Therefore, only the second pattern 200 can be converted into a unique, specific code by a reading device. This is because the information recording medium 1q has the first pattern 113 that has the effect of camouflaging the presence of the second pattern 200.

[0172] 13. Fourteenth Embodiment Next, a fourteenth embodiment of the information recording medium of the present disclosure will be described. FIG. 21 is a plan view illustrating an information recording medium 1r according to the fourteenth embodiment. The information recording medium 1r has a pattern image 314 on one surface of the substrate 2 so as to overlap with the glitter ink layer 5. The pattern image 314 includes a first pattern 114 formed by the colored ink layer 3 and a second pattern 214 formed by the transparent ink layer 4. Both the first pattern 114 and the second pattern 214 are two-dimensional codes. Furthermore, the first pattern 114 and the second pattern 214 are converted into different specific codes.

[0173] The second pattern 214 is formed by superimposing on an area 315, which is a partial area of ​​the first pattern 114. The area 315 is an area other than the cut-out symbols of the first pattern 114. The dot area ratio of the area 315 that overlaps with the second pattern 214 is lower than the dot area ratio of the other areas of the first pattern 114 that do not overlap with the second pattern 214. For example, the dot area ratio of the area 315 is 40% or less. Note that the dot area ratio of the other areas is not particularly limited as long as it is, for example, 45% or more. However, to make the first pattern 114 easier to read, the higher the dot area ratio, the better.

[0174] Furthermore, region 315 is a region that is 20% to 30% in size of the entire region of first pattern 114. If first pattern 114 is, for example, a QR code (registered trademark), it can be read even if the error correction level is Q (25%) or H (30%). In this way, even if region 315 is perceived as a missing portion of the QR code (registered trademark), it is possible to read first pattern 114. Furthermore, second pattern 214 can also be made large enough to be readable.

[0175] 14. Two-Step Authentication Next, a case where two-step authentication is performed using an information recording medium will be described. The information recording medium used for two-step authentication is, for example, an information recording medium 1a (see FIG. 5) or an information recording medium 1r (see FIG. 21), in which both the first pattern and the second pattern are coded as two-dimensional codes or the like. In the following explanation, an information recording medium 1a (see FIG. 5) is read by a reading device 30 (see FIG. 3) and used for authentication.

[0176] (a) Relationship between the information recording medium and the reading device, and reading: The following describes how the appearance of the information recording medium 1a differs depending on the observation angle when the reading device 30 is a smartphone, based on Fig. 22. As explained above, when the reading device 30 is a smartphone, the illumination light source 21 and the reading unit 33 are disposed close to each other.

[0177] Therefore, when the reading device 30 is positioned at position PA where the illumination light source 21 and the reading unit 33 are both perpendicularly opposed to the main surface of the information recording medium 1a, light from the illumination light source 21 is incident on the information recording medium 1a, and specularly reflected light from the information recording medium 1a can be incident on the reading unit 33. At this time, the amount of light reflected from the transparent ink layer 4 of the information recording medium 1a is reduced compared to the amount of light reflected from the glitter ink layer 5 and the colored ink layer 3. Therefore, the contrast between the glitter ink layer 5 and the first pattern 101 of the colored ink layer 3 and the second pattern 200 of the transparent ink layer 4 is clear, with the glitter ink layer 5 and the first pattern 101 of the colored ink layer 3 as the background. As a result, a large amount of light is reflected from the glitter ink layer 5, and a smaller amount of light is reflected from the colored ink layer 3. In other words, the reading unit 33 can capture the second pattern 200 well. The pattern image that can be obtained when the information recording medium 1a is photographed is the pattern image 301b shown in FIG. 22(c).

[0178] On the other hand, when the reading device 30 is tilted at a position PB oblique to the main surface of the information recording medium 1a, light from the illumination light source 21 is incident on the information recording medium 1a, and the exit angle γ' relative to the incident angle γ is the direction of specular reflection. Here, the incident angle γ is, for example, approximately 45 degrees relative to the surface of the information recording medium 1a. Most of the incident light is transmitted through the second pattern 200 formed by the transparent ink layer 4. Therefore, under these conditions, it becomes difficult to photograph the second pattern 200. The incident light is hardly attenuated when passing through the transparent ink layer 4, and the exit light reflected by the underlying glitter ink layer 5 and colored ink layer 3 enters the reading unit 33 almost unchanged as exit light from the transparent ink layer 4. Therefore, the glitter ink layer 5 and the first pattern 101 of the colored ink layer 3 are clearly visible. As a result, the reading unit 33 can properly capture only the first pattern 101. The pattern image that can be acquired when capturing an image of the information recording medium 1a is the pattern image 301a shown in FIG.

[0179] When the light from the illumination light source 21 is turned off with the reading device 30 at position PA where the illumination light source 21 and the reading unit 33 are both perpendicularly opposed to the main surface of the information recording medium 1a, the emitted light due to the ambient light reflected by the underlying glitter ink layer 5 and colored ink layer 3 enters the reading unit 33 almost as it is as emitted light from the transparent ink layer 4. Therefore, the glitter ink layer 5 and the first pattern 101 of the colored ink layer 3 become clear, and the pattern image that can be obtained when the information recording medium 1a is photographed is the pattern image 301a shown in Figure 22(b).

[0180] (b) Configuration of the Information Recording Medium Reading Device The configuration of the reading device 30 described in Fig. 22(a) is the same as that in Fig. 3(a). (c) Contents of the First Pattern and the Second Pattern of the Information Recording Medium As an example, the specific code converted by the first pattern 101 of the information recording medium 1a is the URL of a predetermined web page for authentication, and the specific code converted by the second pattern 200 is a serial number. Then, by combining the two specific codes on the information recording medium 1a, the reading device 30 can complete the code to be read and perform authentication.

[0181] (d) Information Reading Method for Information Recording Medium (Part 1) An example of a method for reading information from information recording medium 1a will be described with reference to FIG. 23 . FIG. 23 is a first flow diagram illustrating the reading of information recording medium 1a by reading device 30. In this first flow, the first pattern 101 and the second pattern 200 on information recording medium 1a are read by changing the position of reading device 30 relative to the reading surface of information recording medium 1a having pattern image 301. First, illumination control unit 41 of reading device 30 turns on illumination light source 21. Then, reading device 30 activates reading unit 33, such as a camera (S471 in FIG. 23 ). Next, reading device 30 is positioned at position PA, and reading device 30 brings pattern image 301 on information recording medium 1a into the field of view of reading unit 33. Reading unit 33 can capture the second pattern 200 clearly. In this state, the image acquisition unit 44 acquires an image of the second pattern 200 from the reading unit 33, and the code identification unit 45 converts the image into a specific code (S472).

[0182] If the code identification unit 45 successfully converts the code into a specific code, the control unit 31 of the reading device 30 acquires the serial number. In this case, the control unit 31 outputs a guide to change the position of the reading device 30 to the display unit 36 ​​(S473 and S474). Specifically, the guide to change the position of the reading device 30 may be, for example, "Please change the position of your smartphone and take a picture from an oblique angle." On the other hand, if the conversion into a specific code fails, a message to that effect is displayed on the display unit 36 ​​(S473 and S479), and the reading process flow in FIG. 23 is then completed. Note that the control unit 31 may complete the reading process flow after repeating the process of S472 several times.

[0183] If the code identification unit 45 is successful in converting the image into a specific code, the reading device 30 is then positioned at position PB, and the reading device 30 brings the pattern image 301 of the information recording medium 1a into the field of view of the reading unit 33. The reading unit 33 can then successfully capture the first pattern 101. In this state, the image acquisition unit 44 acquires the image of the first pattern 101 from the reading unit 33, and the code identification unit 45 converts it into a specific code (S475).

[0184] If the code identification unit 45 successfully converts the image data into a specific code, the control unit 31 of the reading device 30 acquires the URL of the web page. In this case, the control unit 31 uses the URL of the web page to launch a browser (not shown) stored in the program storage unit 38 and transitions to the web page (S476 and S477). On the other hand, if the conversion into a specific code fails, a message to that effect is displayed on the display unit 36 ​​(S476 and S479), and the reading process flow in FIG. 23 is now complete. The control unit 31 may repeat the process of S475 several times before completing the reading process flow.

[0185] If the code identification unit 45 is successful in converting the code into a specific code, the control unit 31 then inputs the previously acquired serial number, which causes the control unit 31 to output a web page to the display unit 36 ​​and terminate the process (S478). If a genuine information recording medium 1a is used, the web page can be displayed on the display unit 36 ​​in this manner. On the other hand, if an unauthorized information recording medium 1a is used, the previously acquired serial number is invalid, and therefore the web page cannot be output to the display unit 36 ​​by inputting the previously acquired serial number. Therefore, an error message is displayed on the display unit 36 ​​(S478 and S479).

[0186] (e) Information Reading Method for Information Recording Medium (Part 2) Next, another example of a method for reading information from information recording medium 1a will be described with reference to FIG. 24 . FIG. 24 is a second flow diagram illustrating a method for reading information recording medium 1a by reading device 30. In this second flow, the first pattern 101 and the second pattern 200 on information recording medium 1a are read by turning on and off the illumination light source 21 without changing the position of reading device 30 relative to the surface of information recording medium 1a. First, the illumination control unit 41 of reading device 30 turns off the illumination light source 21. Then, reading device 30 activates the reading unit 33, such as a camera (S481 in FIG. 24 ). Next, reading device 30 is positioned at position PA, and reading device 30 brings the pattern image 301 on information recording medium 1a into the field of view of reading unit 33. The reading unit 33 can capture a good image of first pattern 101. In this state, the image acquisition unit 44 acquires an image of the first pattern 101 from the reading unit 33, and the code identification unit 45 converts the image into a specific code (S482).

[0187] If the code identification unit 45 is successful in converting the image data into a specific code, the control unit 31 of the reading device 30 acquires the URL of the web page. In this case, the control unit 31 uses the URL of the web page to launch a browser (not shown) stored in the program storage unit 38 and transitions to the web page (S483 and S484). On the other hand, if the conversion into a specific code is unsuccessful, a message to that effect is displayed on the display unit 36 ​​(S483 and S489), and the reading process flow in FIG. 24 is now complete. Note that the control unit 31 may repeat the process of S482 several times before completing the reading process flow.

[0188] If the code identification unit 45 has succeeded in converting the information into a specific code, the illumination control unit 41 of the reading device 30 then turns on the illumination light source 21, and the reading device 30 brings the pattern image 301 of the information recording medium 1a into the field of view of the reading unit 33. The reading unit 33 can then successfully photograph the second pattern 200. In this state, the image acquisition unit 44 acquires the image of the second pattern 200 from the reading unit 33, and the code identification unit 45 converts it into a specific code (S485).

[0189] If the code identification unit 45 is successful in converting the code into a specific code, the control unit 31 of the reading device 30 acquires the serial number. In this case, the control unit 31 transmits the serial number to the web page for authentication (S486 and S487). On the other hand, if the conversion into a specific code fails, a message to that effect is displayed on the display unit 36 ​​(S486 and S489), and the reading process flow in FIG. 24 is now complete. Note that the control unit 31 may complete the reading process flow after repeating the process of S485 several times.

[0190] If authentication is successful in the processing of S478, the control unit 31 outputs, for example, a web page indicating successful authentication to the display unit 36, and terminates the processing (S488). If a genuine information recording medium 1a is used, the web page indicating successful authentication can be displayed on the display unit 36, allowing further processing to be performed. On the other hand, if an unauthorized information recording medium 1a is used, the acquired serial number is invalid, and authentication cannot be performed even if the serial number is entered. Therefore, an error message is displayed on the display unit 36 ​​(S488 and S489).

[0191] (f) Information Reading Method of Information Recording Medium (Part 3) Next, another example of a method for reading information from information recording medium 1r will be described with reference to FIG. 25. Information recording medium 1r can be read using the reading processes shown in FIGS. 23 and 24, but the reading process shown in FIG. 25, which will be described next, can further improve reading performance. FIG. 25 is a third flow diagram relating to reading of information recording medium 1r by reading device 30. FIG. 26 is a diagram showing an example of processing by reading device 30 relating to reading of information recording medium 1r in the third flow. The third flow involves devising a method for reading device 30 when reading second pattern 214 of information recording medium 1r.

[0192] First, the illumination control unit 41 of the reading device 30 turns off the illumination light source 21. Then, the reading device 30 activates the reading unit 33, such as a camera (S491 in FIG. 25). Next, the reading device 30 is positioned at position PA, and the pattern image 314 on the information recording medium 1r is brought into the field of view of the reading unit 33. FIG. 26A shows an example of the display of the reading device 30 when the first pattern 114 is captured properly. The display unit 36 ​​displays a display screen 361 showing a red frame 361a. The pattern image 314 is then adjusted so that it fits within the red frame 361a, and the reading unit 33 captures the image. The reading unit 33 can capture the first pattern 114 properly. In this state, the image acquisition unit 44 acquires the image of the first pattern 114 from the reading unit 33, and the code identification unit 45 converts it into a specific code (S492).

[0193] If the code identification unit 45 successfully converts the code into a specific code, the control unit 31 of the reading device 30 acquires the URL of the webpage. In this case, the control unit 31 sets a mask (S493 and S494). FIG. 26B shows an example of a processing screen 371 of the reading device 30 when a mask is set. The processing screen 371 is recognized as an internal processing screen and is not displayed on the display unit 36. The display unit 36 ​​may continue to display the display screen 361 shown in FIG. 26A. The processing screen 371 allows an area 371a corresponding to the area 315 including the second pattern 214 to be photographed, and masks the remaining area 371b. The position and size of the area 371a on the processing screen 371 may be, for example, stored in the first pattern 114, or may be predefined in a program.

[0194] On the other hand, if conversion to a specific code has failed, a message to that effect is displayed on the display unit 36 ​​(S493 and S499), and the reading process flow in Fig. 25 is now complete. Note that the control unit 31 may complete the reading process flow after repeating the process of S492 several times.

[0195] If the code identification unit 45 is successful in converting the information recording medium 1r into a specific code, the illumination control unit 41 of the reading device 30 then turns on the illumination light source 21, and the reading device 30 brings the second pattern 214 of the information recording medium 1r into the field of view of the reading unit 33 using the processing screen 371 of the reading device 30 when a mask has been set. The reading unit 33 can then successfully capture the second pattern 214. In this state, the image acquisition unit 44 acquires an image of the second pattern 214 from the reading unit 33, and the code identification unit 45 converts the image into a specific code (S495). The processing from S496 onwards is the same as the processing from S476 onwards in FIG. 23 .

[0196] It should be noted that the method of reading information from information recording medium 1r described above is not limited to the information recording medium 1r in which the dot area ratio of region 315 of first pattern 114 that overlaps second pattern 214 is set lower than the dot area ratio of other regions of first pattern 114. Processing can also be performed favorably for other information recording mediums in which the dot area ratio of the first pattern is uniform and the second pattern is arranged overlapping a partial region of the first pattern.

[0197] (g) Others In the above example of two-step authentication, the first pattern is a specific code converted into the URL of the website where authentication is performed, and the second pattern is a specific code converted into a serial number, but this is not limiting. For example, the second pattern may be a specific code converted into an encrypted serial number, and authentication may be performed after decrypting it on the website.

[0198] Although not shown in the drawings, information recording media that are modifications of the information recording media 1 of the first embodiment of the present disclosure will be described below. However, the following modifications are not limited to the information recording media 1 of the first embodiment, and can also be applied as modifications of other embodiments.

[0199] (a) Variation 1 The information recording medium 1j according to Variation 1 is a transparent ink formed by mixing, at least in part, a material that emits visible light when excited by infrared or ultraviolet light, which are used as authentication materials, into the ink forming the transparent ink layer 4j. That is, when the ink forming the transparent ink layer 4j is irradiated with light in the infrared or ultraviolet wavelength range, electrons in the illuminant contained in the ink are excited, and as the excited electrons return to their ground state, they release excess energy as visible light. The wavelength range of the infrared light referred to here may be, for example, 0.78 μm or more and 1 mm or less, and the wavelength range of the ultraviolet light may be, for example, 0.01 μm or more and 0.38 μm or less. However, the ink may be excited by, for example, terahertz waves, millimeter waves, X-rays, gamma rays, or the like, as long as it emits visible light, even if the wavelength range is longer than infrared or shorter than ultraviolet.

[0200] Materials that are excited by infrared light and emit visible light are also called upconversion luminescent materials. Examples include those containing at least one rare earth element selected from the group consisting of erbium (Er), holmium (Ho), praseodymium (Pr), thulium (Tm), neodymium (Nd), gadolinium (Gd), europium (Eu), samarium (Sm), terbium (Tb), dysprosium (Dy), and cerium (Ce), and in which the base material of the phosphor particles is a halide or the like. While some of these materials overlap with those described above, examples of such materials include those disclosed in Japanese Patent Laid-Open Publication No. 7-297475.

[0201] Furthermore, examples of materials that are excited by ultraviolet light and emit visible light include dyes such as fluorescein-based fluorescent dyes, coumarin-based fluorescent dyes, and rhodamine-based fluorescent dyes, and examples of inorganic pigments include europium-manganese-activated barium magnesium aluminate, manganese-activated zinc silicate, europium-activated yttrium oxide, europium-activated yttrium sulfide, zinc oxide, manganese-activated zinc germanate, and europium-activated yttrium phosphovanadate.

[0202] In this way, by using ink that forms the transparent ink layer 4j of the information recording medium 1j made of a transparent material that is excited by infrared or ultraviolet light and emits visible light, the following effect can be obtained: That is, it is possible to improve and complement the accuracy of the anti-counterfeiting function of the present disclosure by utilizing the difference in appearance between the first pattern 100 made of the colored ink layer 3 and the second pattern 200 made of the transparent ink layer 4j, which is caused by the relationship between the irradiation angle of visible light and the observation angle.

[0203] In addition to the difficulty of reading and copying the second pattern 200 under visible light irradiation conditions, the visibility of the transparent ink layer 4j can be increased only when irradiated with infrared or ultraviolet light in a specific wavelength range, with little effect from the glitter ink layer 5 or the colored ink layer 3. This ensures an even greater level of difficulty in reading and copying. A transparent ink may also be formed by mixing both a material that emits visible light when excited by infrared light and a material that emits visible light when excited by ultraviolet light. This improves the visibility of the transparent ink layer 4j when irradiated with either of the two types of invisible light, thereby improving convenience.

[0204] Furthermore, during the manufacturing process of the information recording medium 1j, it is difficult to directly visually confirm whether the transparent ink layer 4 correctly forms the predetermined second pattern 200. However, in this embodiment, by irradiating the transparent ink layer 4j with infrared or ultraviolet light in a specific wavelength range during or after its formation, the transparent ink layer 4j emits visible light, making it easy to confirm the presence of the second pattern 200. This can therefore contribute to improving the quality of the information recording medium 1j.

[0205] (b) Modification 2 Next, the information recording medium 1k according to Modification 2 is an information recording medium in which an infrared absorbing material, which is an authenticity determining material, is mixed into at least a portion of the ink forming the transparent ink layer 4k, thereby forming a transparent ink. Examples of organic dyes that absorb light in the infrared wavelength range include polymethylene-based, phthalocyanine-based, azo-based, and anthraquinone-based compounds, and examples of inorganic infrared absorbers include antimony-doped tin oxide and tin-doped indium oxide.

[0206] In this way, by using an ink made of a transparent material containing an infrared-absorbing material to form the transparent ink layer 4k of the information recording medium 1k, the same effect as in Variation 1 can be achieved. That is, the second pattern 200 is made difficult to read and copy under visible light irradiation conditions. In addition, only when irradiated with infrared light in a specific wavelength range, the second pattern 200 in the transparent ink layer 4k can be clearly recognized by a measuring means such as an infrared camera, with almost no influence from the glitter ink layer 5 or the colored ink layer 3. This further ensures the difficulty of reading and copying.

[0207] Furthermore, in this embodiment, during or after the formation of the transparent ink layer 4k, infrared light in a specific wavelength range can be irradiated, and the absorption and reflection state of the infrared light can be visualized using an infrared camera, etc. Therefore, the formation state of the transparent ink layer 4k, which is difficult to check with the naked eye, can be easily checked using an infrared camera, etc., which can contribute to improving the quality of the information recording medium 1k.

[0208] (c) Variation 3 Furthermore, the information recording medium 1m according to Variation 3 is constructed using a transparent ink that contains a polarizing material, which is an authenticity determining material, in at least a portion of the ink forming the transparent ink layer 4m. Examples of such polarizing materials include an absorptive polarizer obtained by impregnating polyvinyl alcohol with iodine or a dichroic dye and then stretching and aligning it, an absorptive polarizer obtained by aligning a dichroic dye on an alignment film, a reflective circular polarizer obtained by aligning cholesteric liquid crystal on a substrate, and a reflective polarizer formed by laminating birefringent multilayer films. Note that any other element that has the property of being able to extract polarized components of a specific direction from reflected or transmitted light can also be used.

[0209] Such a transparent ink layer 4m containing a polarizing material can be formed, for example, by the method described in Japanese Patent No. 6519582. First, an alignment film solution is prepared by dissolving an alignment film resin, and this is applied to the substrate 2 by a microgravure method while masking areas other than a predetermined pattern image to form a coating film. Next, an alignment treatment is performed by rubbing the coating film in a predetermined direction with a rubbing cloth, thereby obtaining an alignment film. Next, a dichroic dye is added to a UV-curable liquid crystal to prepare a polarizer solution.

[0210] Then, a polarizer solution is applied to the alignment film to a predetermined thickness using a microgravure method to form a coating film. Next, the coating film is annealed, and UV light is irradiated to the coating film in an oxygen atmosphere to harden the coating film, thereby forming a transparent ink layer 4m with a polarization function having a transmission axis in a predetermined direction. Alternatively, after the transparent ink layer 4m is formed over the entire surface of a predetermined region of the substrate 2 without masking, a laser beam in a predetermined wavelength range is irradiated onto the non-pattern image forming portion to thermally destroy the liquid crystal molecules in that portion, thereby providing polarization function only to the pattern image portion.

[0211] In this way, by using an ink made of a transparent material containing a polarizing material as the ink forming the transparent ink layer 4m of the information recording medium 1m, the same effects as those of Modifications 1 and 2 can be obtained. That is, in addition to the difficulty of reading and copying the second pattern 200 under visible light irradiation conditions, only when a specific polarizing film is used can the visibility of the transparent ink layer 4m be increased with almost no influence from the glittering ink layer 5 or the colored ink layer 3. This can ensure an even greater degree of difficulty in reading and copying.

[0212] Furthermore, the transparent ink layer may be configured as an embodiment that includes any or all of the above-mentioned variations 1 to 3. For example, the ink forming the transparent ink layer may be configured from a transparent ink containing an infrared-absorbing material in addition to a material that is excited by infrared or ultraviolet light and emits visible light. Alternatively, the ink forming the transparent ink layer may be configured from a transparent ink containing a polarizing material in addition to containing an infrared-absorbing material. This increases the number of verification methods for authenticity determination, further contributing to ensuring the difficulty of reading and copying.

[0213] In addition, in this embodiment, by using a specified polarizing film during or after the formation of the transparent ink layer 4m, the formation state of the transparent ink layer 4m, which is difficult to see with the naked eye, can be easily confirmed, contributing to improving the quality of the information recording medium 1m.

[0214] The authenticity determination device 60 that determines the authenticity of the information recording medium 1 described in the first embodiment can perform the functions of the above-mentioned authenticity determination device 60 by, for example, having the control unit 31a execute a predetermined program. The program, which is executed by a computer included in the authenticity determination device 60, reads the first pattern information of the information recording medium when the illumination light source is turned on at a first light intensity, including an off state, and converts the read first pattern information into a first specific code. The program also identifies a reading position of the second pattern based on the first specific code, and reads the second pattern information of the information recording medium when the illumination light source is turned on at a second light intensity greater than the first light intensity, and converts the read second pattern information into a second specific code. The program also compares the second specific code with comparison information for authenticity determination, and determines that the information recording medium is authentic if the two match, and determines that the information recording medium is not authentic if the two do not match.

[0215] REFERENCE SIGNS LIST 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1m, 1n, 1p, 1r Information recording medium 2 Substrate 3 Colored ink layer 4, 4j, 4k, 4m Transparent ink layer 5 Glossy ink layer 10 Printed matter 11 Paper 12 Printing unit 21 Illumination light source 22 Viewpoint 22a Viewpoint at position P1 22b Viewpoint at position P2 22c Viewpoint at position P3 30, 30a Reading device 31, 31a, 31b, 31c Control unit 32, 32a, 32b, 32c Memory unit 33 Reading unit 35 Operation unit 36 ​​Display unit 41 Illumination control unit 42 First pattern position specifying unit 43 Second pattern position specifying unit 44 Image acquisition unit 45 Code identification unit 46 Authentication determination unit 51 First pattern position identification information 52 Second pattern position identification information 53 Authentication determination information 60, 60a Authentication determination device 100, 101, 102, 103, 104, 111, 114 First pattern 101p Extracted symbol 200, 201, 202, 203, 204, 205, 206, 207, 208, 212, 214 Second pattern 201a, 201b, 201c, 201d, 202a, 202b, 202c, 202d, 203a, 203b, 203c, 203d, 204a, 204b, 204c, 204d, 204e, 204f, 204g, 204h, 204i, 205a, 205c, 205g, 205i, 206a, 206b, 207a, 207b, 208b, 208d, 208g, 208i, 208l, 208n Partial patterns 200p, 201p, 202p, 203p, 204p, 205p, 208p Extraction symbols 205b, 205d, 205e, 205f, 205h, 208a, 208c, 208e, 208f, 208h, 208j, 208k, 208m, 208o Dummy part patterns 300, 300a, 300b, 301, 302, 303, 304, 305, 306, 307, 308, 309, 311, 312, 314 Pattern images 500p, 501p Extraction symbols 511, 512 Basic patterns

Claims

1. An information recording medium comprising: a substrate; a first layer formed on one side of the substrate using a photoluminescent material; a second layer formed on the one side using a colored ink; and a third layer formed on the one side using a transparent ink, wherein the second layer forms a first pattern, and the third layer forms a second pattern, wherein at least a portion of the first pattern and the second pattern each overlap with an area in which the first layer is formed in a planar view, and the second pattern includes information that can be converted into a specific code, and at least a portion of the second pattern overlaps with the first pattern in a planar view.

2. The information recording medium according to claim 1, wherein said first layer is formed as a solid, or as halftone dots or lines having a halftone dot area ratio of 80% or more.

3. The information recording medium according to claim 1, wherein the second pattern is made up of a plurality of partial patterns.

4. The information recording medium according to claim 3, wherein only some of said plurality of partial patterns contain information that can be converted into said specific code.

5. The information recording medium according to claim 1, wherein the second pattern is a two-dimensional code composed of a plurality of partial patterns, each of which has one or more cut-out symbols, and all of the cut-out symbols are positioned at the ends of the second pattern.

6. The information recording medium of claim 5, wherein the second pattern is composed of a plurality of partial patterns, and when the plurality of partial patterns are a first partial pattern, a second partial pattern, and a third partial pattern sandwiched between the first partial pattern and the second partial pattern, a first cut-out symbol arranged on the second partial pattern side of the first partial pattern and a second cut-out symbol arranged on the first partial pattern side of the second partial pattern constitute at least two cut-out symbols of the third partial pattern, and the third partial pattern constitutes dummy information that cannot be converted into the specific code.

7. An information recording medium according to any one of claims 1 to 5, wherein the first pattern includes information that can be converted into a specific code different from the second pattern.

8. An information recording medium according to claim 7, wherein, in a plan view, the entire area of ​​said second pattern overlaps with a portion of said first pattern, and said portion of said first pattern has a lower dot area ratio than the remaining portion.

9. An information recording medium according to any one of claims 1 to 5, wherein the third layer is composed of the transparent ink that is excited by infrared or ultraviolet light and emits visible light.

10. An information recording medium according to any one of claims 1 to 5, wherein the third layer is composed of ink containing an infrared absorbing material.

11. An information recording medium according to any one of claims 1 to 5, wherein the third layer is formed of ink containing a polarizing material.

12. A printed matter comprising an information recording medium according to any one of claims 1 to 5.

13. A reading device for reading an information recording medium described in any one of claims 1 to 5, comprising: an illumination light source; a reading unit arranged in a position close to the illumination light source; and a control unit, wherein the control unit turns on the illumination light source, causes the reading unit to read the one side of the information recording medium, and when first information has been read, outputs guidance for changing the reading angle of the reading device according to the read information, and after outputting the guidance, causes the reading unit to read the one side of the information recording medium, and determines whether second information different from the first information has been read.

14. A reading device as described in claim 13, wherein the first pattern of the information recording medium includes information that can be converted into a specific code different from the second pattern, and the control unit, when the first information is the second pattern, outputs the guidance to change the reading angle of the reading device to an oblique direction relative to the surface of the information recording medium, and determines whether the first pattern has been read as the second information.

15. A reading device as described in claim 13, wherein the first pattern of the information recording medium includes information that can be converted into a specific code different from the second pattern, and the control unit, when the first information is the first pattern, outputs the guidance to change the reading angle of the reading device in a direction perpendicular to the surface of the information recording medium, and determines whether the second pattern has been read as the second information.

16. A reading device for reading an information recording medium as claimed in any one of claims 1 to 5, comprising: an illumination light source; a reading unit arranged in a position close to the illumination light source; and a control unit, wherein the first pattern of the information recording medium includes information that can be converted into a specific code different from the second pattern, and the control unit causes the reading unit to read the one side of the information recording medium with the illumination light source turned off, and when the first pattern has been read, turns on the illumination light source and causes the reading unit to read the one side of the information recording medium, and determines whether the second pattern has been read.

17. A reading device as described in claim 16, wherein, when the first pattern is read, the control unit turns on the illumination light source, shields all areas readable by the reading unit except for a designated area so that the area cannot be read, and causes the reading unit to read the one side of the information recording medium.

18. A reading method for reading an information recording medium described in any one of claims 1 to 5 by a reading device equipped with an illumination light source and a reading unit arranged in close proximity to the illumination light source, the reading method including the following steps by the reading device: turning on the illumination light source; causing the reading unit to read the one side of the information recording medium; when first information has been read, outputting guidance for changing the reading angle of the reading device in accordance with the read information; after outputting the guidance, causing the reading unit to read the one side of the information recording medium; and determining whether second information different from the first information has been read.

19. A reading method for reading an information recording medium described in any one of claims 1 to 5 by a reading device equipped with an illumination light source and a reading unit positioned in close proximity to the illumination light source, wherein the first pattern of the information recording medium includes information that can be converted into a specific code different from the second pattern, and the reading device includes the following steps: causing the reading unit to read the one side of the information recording medium with the illumination light source turned off; when the first pattern has been read, turning on the illumination light source and causing the reading unit to read the one side of the information recording medium; and determining whether the second pattern has been read.

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