JP2014141005A - Method of reading antifalsification medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of reading an antifalsification medium for authenticity determination by mechanical reading which enhances difficulty of falsification and can improve accuracy of authenticity determination.SOLUTION: In a method of reading an antifalsification medium, there are provided two types of security parts which are formed on a substrate and have characteristic absorption in at least a part of near infrared wavelengths, and the security parts have a mutually superimposed part. In the superimposed part, one or both of the security pats is imparted with deep to pale color gradation. The reflection ratios of specific wavelength in the two types of the security parts are measured along lines at two or more different positions by using at least two types of photodetectors, and authenticity determination is conducted by comparing individual measurement results mutually.

Description

  The present invention relates to a method for reading an anti-counterfeit medium that performs authenticity determination by machine reading by a sensor.

  Conventionally, in addition to banknotes, stock certificates, gift certificates, and other securities such as credit cards, printing with sophisticated printing technology to prevent unauthorized use due to counterfeiting and duplication, such as seals and tags for products However, in view of the frequent occurrence of unauthorized use due to counterfeiting and duplication in recent years, in addition to these fine prints, forgery prevention measures using special inks have come to be implemented. .

  For example, fluorescent ink that emits light in the visible light region when irradiated with ultraviolet light, OVD (Optically Variable Device) ink whose color and brightness change depending on the viewing angle, etc., are printed on paper, making copies such as color copies. There are methods that cannot be easily counterfeited by machine.

  However, as for the recent counterfeit products, elaborate counterfeit products in which a product imitating the above-described fluorescent ink or OVD is added in addition to the color copy. These counterfeit products can be easily discriminated if compared with genuine products and viewed by experts, but it is difficult to determine whether the counterfeit products are genuine or not even by ordinary people.

  Therefore, in addition to visual determination of authenticity, there are many securities that use anti-counterfeit measures that perform authenticity determination by machine reading using sensors. This is also effective for a bill discriminator of a vending machine, for example, in which true / false judgment cannot be made visually. As a measure for preventing counterfeiting by machine reading, there is a general method in which a material that reacts with a sensor that can detect the functionality is mixed into the ink, although the functionality cannot be seen with the naked eye. For example, a magnetic ink in which magnetic powder is mixed in the ink is visually visible as a black ink, but an MR (Magneto Resistive) sensor can determine the presence or absence of magnetism.

  In addition, there is a forgery prevention measure using ink that absorbs or transmits a part of the near infrared region, focusing on infrared rays, particularly near infrared rays. For example, there is a method of combining black ink, which is mainly composed of carbon black, which is a process ink, and black ink, which has no absorption in the near-infrared region. Examples thereof include a method using an ink having absorption in the part, and a method in which an ink having absorption in a part of the near infrared region is mixed into another process ink (other than black).

  However, in order to perform machine reading by these sensors, there is a problem that costs for introducing the equipment are generated. Further, when authenticity determination is performed with an inexpensive sensor or a small number of reading points, there is a possibility that even a forged product may be determined as a genuine product.

  In the case where only the feature point in the near infrared region is detected by the sensor and the authenticity determination is performed, it cannot be distinguished from a counterfeit product imitating only the feature point. Therefore, it is possible to take a countermeasure against simple counterfeiting by detecting a plurality of feature points and performing authenticity determination.

  In addition, inks with characteristics in the near infrared region can be mixed with multiple types of optical functional materials, resulting in complex spectral waveforms. If these feature points are detected, it becomes a forgery prevention medium that is extremely difficult to counterfeit. Can be.

  The anti-counterfeiting measures listed above are effective when performed in addition to visual authenticity determination. However, when anti-counterfeit determination is performed only by machine reading without performing visual authenticity determination, anti-counterfeit ink Even if the spectral waveform is complicated, it may be imitated. For example, if the light is controlled by the optical multilayer film, a similar waveform can be created if the manufacturing cost and appearance of the medium are repeated. In this case, if it can be visually confirmed, it can be recognized as a counterfeit product at a glance, but it is not suitable for an article whose authenticity is determined only by machine reading.

  Therefore, two types of security parts that have characteristic reflection and absorption in the near-infrared region are printed with security ink, and gradation is added so that the density of the two parts complements each other. There is a method of providing. It is difficult to reproduce such gradation with an optical multilayer film by reading the wavelength of the feature point with a sensor and capturing the change in reflectance by moving the sensor in the gradation direction.

  However, the above-described reading method has accuracy of true / false judgment when the light receiving diameter of the reading sensor is small, but when the light receiving diameter is large, similar reflection can be achieved by cutting and pasting the optical multilayer film in a triangular shape, for example, in a triangular shape. Rate can be obtained. In order to reduce the cost of the reader, it is necessary to use a sensor having a large light receiving diameter of the reading sensor, and further contrivance is required for the reading method.

JP 2005-74641 A JP-A-7-37027 Japanese Patent No. 3246017 JP 2009-149068 A

  SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide a forgery prevention medium reading method that is highly difficult to forgery and that can further improve the accuracy of true / false determination in a forgery prevention medium that performs authenticity determination by machine reading. .

  A method for reading a forgery prevention medium according to claim 1 of the present invention is constituted by two types of security sections having absorption characteristic of at least a part of the near infrared wavelength region on a base material, The security part is provided with overlapping portions, and the overlapping part is a method for reading a forgery prevention medium in which one or both of the security parts are shaded from dark to light. The reflectance at a specific wavelength is measured in at least two lines using at least two types of light receiving elements, and the authenticity is determined by comparing the measurement results.

  A method for reading an anti-counterfeit medium according to claim 2 of the present invention is the method for reading an anti-counterfeit medium according to any one of claims 1 to 3, wherein at least two types of light receiving elements that measure the reflectance at the specific wavelength are used. The light receiving portions by are adjacent to each other.

  A method for reading an anti-counterfeit medium according to claim 3 of the present invention is the method for reading an anti-counterfeit medium according to any one of claims 1 to 3, wherein at least two types of light receiving elements for measuring the reflectance at the specific wavelength are used. The light receiving portions by are crossed with each other.

  According to the present invention, the reflectance at a specific wavelength in the two types of security parts of the anti-counterfeit medium is measured in at least two lines using at least two types of light receiving elements, and the true result is obtained by comparing the measurement results. By performing forgery determination, it is possible to provide a method for reading an anti-counterfeit medium that is highly difficult to counterfeit and that can further improve the accuracy of authenticity determination in an anti-counterfeit medium that performs authenticity determination by machine reading.

FIG. 3 is a schematic diagram illustrating a method for reading a forgery prevention medium according to an embodiment of the invention. Sectional drawing which shows the structure of a forgery prevention medium typically. The graph which shows the spectral characteristic in embodiment of the 1st security part of a forgery prevention medium, and a 2nd security part. FIG. 2 is a schematic diagram schematically showing a configuration of a reading sensor. The conceptual diagram which shows the relationship between a forgery prevention medium and a sensor output. The conceptual diagram which shows the relationship between the forgery medium produced imitating the forgery prevention medium, and the sensor output with respect to this forgery medium. The schematic diagram which showed the positional relationship of the reading sensor, and the shape of the forgery medium. The schematic diagram which showed the positional relationship of the reading sensor, and the shape of the forgery medium.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram illustrating a method for reading an anti-counterfeit medium according to an embodiment of the present invention. The anti-counterfeit medium 1 includes a first security unit 12, a second security unit 13, and a gradation unit 14, and a portion where the first security unit 12 and the second security unit 13 overlap is the gradation unit 14. The security unit 12 is provided by changing the density continuously from a dark color to a light color, and the second security unit 13 is continuously changed from a light color to a dark color.

  The anti-counterfeit medium 1 has, for example, a rectangular shape, and the first security unit 12, the gradation unit 14, the second security unit 13, the gradation unit 14, and the first security unit 12 are sequentially arranged in that order in parallel to the short side. Is provided.

  A reading sensor 15 and a reading sensor 16 are provided for the anti-counterfeit medium 1 configured as described above. The reading sensors 15 and 16 read the change in reflectivity by moving in a direction perpendicular to the short side of the forgery prevention medium 1, for example, from the left to the right of the drawing (in the direction of the broken arrow in the figure). It is configured.

  The reading sensors 15 and 16 have a light receiving diameter of the light receiving element, for example, between φ0.5 and φ10, and are configured with commercially available light receiving elements or a combination of the light receiving elements.

  FIG. 2 schematically shows the structure of the forgery prevention medium 1. The anti-counterfeit medium 1 is provided with a first security part 12 and a second security part 13 on a base material 11, and the gradation part 14 has a continuous thickness of the first security part 12 and the second security part 13. Is changing.

  FIG. 3 is a graph showing spectral characteristics in the embodiment of the first security unit 12 and the second security unit 13. The spectral waveform 22 is the first security unit 12 and the spectral waveform 23 is the second security unit 13. In the spectral characteristic graph, the first security unit 12 and the second security unit 13 appear to be black by visual observation because they show absorption almost in the entire visible light region. The color in the visible light region is not limited to black and may be any number.

  In addition, both or one of the first security unit 12 and the second security unit 13 are at least partially absorbed in the near-infrared wavelength region, and the absorption range may be wide, but the narrower one is counterfeit. The prevention effect is high and can be applied to various combinations.

  FIG. 3 shows an example in which a reading sensor is provided. The authenticity determination is performed by providing a reading sensor at a wavelength where the difference in reflectance between the first security unit 12 and the second security unit 13 in the visible light region and the near-infrared region is 5% or more, preferably 20% or more. In FIG. 3, sensor S2 and sensor S3 correspond to this.

  Further, by providing a reading sensor at a wavelength where the difference in reflectance between the first security unit 12 and the second security unit 13 is 10% or less, preferably 5% or less, the accuracy of authenticity determination is further improved. . In FIG. 3, sensor S1 and sensor S4 correspond to this.

  FIG. 4 schematically shows a specific configuration example of the reading sensors 15 and 16, and light sources (for example, LEDs) 34 to 37 corresponding to the wavelengths of the sensors S1 to S4 shown in the graph of FIG. Thus, the light source 34 to 37 irradiates the anti-counterfeit medium 1 and surrounds one light receiving element 31 that receives the reflected light. As long as the light receiving element 31 can receive the reflected light from the light sources 34 to 37, the configuration shown in FIG. The light receiving element 31 may be provided with a light shielding plate 32 so as not to read the direct light from the light sources 34 to 37. For example, the reading sensors 15 and 16 may be configured as described in Japanese Patent Publication No. 61-15471.

  FIG. 5 is a conceptual diagram showing the relationship between the anti-counterfeit medium 1 and the sensor output. The sensor output graph 4 and the sensor output graph 6 move the reading sensors 15 and 16 on the anti-counterfeit medium 1 from left to right. In this case, the relationship between the reflectances of the reading sensors 15 and 16 is shown. In the sensor output graphs 4 and 6, 44 indicates the output of the sensor S1, 45 indicates the output of the sensor S2, 46 indicates the output of the sensor S3, and 47 indicates the output of the sensor S4.

  The gradation part 14 of the anti-counterfeit medium 1 applies gradation so that the density is between 100% and 0% between the left side and the right side of the gradation part 14 when the density of the first security part 12 on the left side is 100%. It is. Similarly, gradation is applied between the right side and the left side of the gradation unit 14 so that the density of the second security unit 12 is 100% to 0%, and the first security unit 12 and the second security unit It is preferable that the gradation is adjusted to be 100% when the density of 13 is added.

  The change in reflectance at each wavelength of the reading sensor 15 of the gradation part 14 of the anti-counterfeit medium 1 adjusted as described above is as shown in the sensor output graph 4, and the change in the reflectance of the reading sensor 16 is the sensor As shown in the output graph 6. By comparing the outputs and waveforms of the two graphs 4 and 6 to determine the authenticity, it is possible to make a more accurate authenticity determination, and at the same time, it becomes a forgery prevention medium that is very difficult to forge.

  When the gradation portion 14 is provided by printing, there is a rainbow printing method as a method for gradation of the ink of the first security portion 12 from a dark color to a light color. A partition plate is provided in the ink supply jar of the offset printing machine where the gradation is to be applied to prevent ink from flowing except for the partition. A desired gradation is formed by adjusting the width of the horizontal swing roller for making the density of the ink uniform left and right to a width where gradation is desired. The gradation part 14 is formed by printing by putting the ink of the second security part 13 on the opposite side of the partition plate of the ink supply pot.

  There is a gradation expression method using halftone dots as another method of applying gradation. The printing plate is designed so that the halftone dot density of the first security unit 12 is 100% to 0% and the halftone dot density of the second security unit 13 is 0% to 100%, so that the density of both is 100%. By multiplying, the gradation portion 14 is formed by printing.

  The halftone dot density is not particularly limited to 100% and 0% as long as the density difference between the start point and the end point is 20% or more.

  FIG. 6 shows a forgery medium 7 produced by imitating the reading characteristics of the anti-counterfeit medium 1, and waveforms obtained by measuring the forgery medium 7 by the method for reading the anti-counterfeit medium according to the present embodiment. A first security unit 73 is a second security unit, and 74 is a gradation unit.

  The counterfeit medium 7 has a configuration in which the spectral waveform 22 of the first security unit 12 and the spectral waveform 23 of the second security unit 13 shown in FIG. 3 are reproduced by an optical multilayer thin film, and the gradation unit 74 is cut and pasted into an isosceles triangle shape. It has become. When the length of the base of the isosceles triangle is equal to or less than the reading diameter of the reading sensors 15 and 16, the output waveforms of the reading sensors 15 and 16 cause an output change similar to that of the gradation unit 74.

  When the reading diameters of the reading sensors 15 and 16 are sufficiently small, when the optical multilayer thin film is cut into an isosceles triangle shape having a small base, a crack is formed in the electromagnetic dielectric layer forming the optical multilayer film, so that sufficient optical characteristics can be obtained. However, it is not desirable to reduce the reading diameters of the reading sensors 15 and 16 because the sensor parts are downsized and complicated, resulting in an increase in sensor cost.

  In FIG. 6, when the reading sensor 15 and the reading sensor 16 are arranged adjacent to each other and read, the sensor output graph 8 in the case where the reading sensor 15 is read in accordance with the vertex of the isosceles triangle of the forged medium 7 is shown in FIG. 5. The sensor output graph 4 may have the same waveform 85 as the output 45 of the sensor S2, but the sensor output graph 9 of the adjacent reading sensor 16 has a waveform 86 different from that of the sensor output graph 8, so that the counterfeit product is determined. Is possible.

  However, as shown in FIG. 7, when the shape of the first security unit 72 is cut and pasted at a period that matches the reading diameter of the reading sensors 15 and 16, both sensor output waveforms may be the same.

  In order to improve this point, when the reading sensors 15 and 16 are arranged so as to overlap each other as shown in FIG. 8, the points where the outputs of the two match are asymmetrical, and even if the matching points are slightly shifted, both sensor output waveforms Is different, it is extremely difficult to always match both sensor output waveforms.

  As described above, according to the above-described embodiment, two types of security parts having characteristic reflection and absorption in the near-infrared region are printed with security ink, and the overlapping part of two types of security parts is The anti-counterfeit medium is provided with gradations so that the density complements each other, and the authenticity is determined by reading the reflectance of the characteristic points of the security part with a characteristic spectral waveform with an optical sensor, and further anti-counterfeiting An optical sensor provided with at least two measurement points on the medium moves to detect increase / decrease in reflectivity in the gradation part and compare whether the output waveform of each optical sensor is the same. An anti-counterfeit medium that performs anti-counterfeit judgment by reading, has high anti-counterfeiting, and can improve anti-counterfeit accuracy. It is possible to provide a preparative method.

  DESCRIPTION OF SYMBOLS 1 ... Anti-counterfeit medium, 11 ... Base material, 12 ... 1st security part, 13 ... 2nd security part, 14 ... Gradation part, 15, 16 ... Reading sensor, S1-S4 ... Sensor, 31 ... Light receiving element, 32 ... light shielding plate, 34 to 37 ... light source.

Claims (3)

It is composed of two types of security parts that have characteristic absorption in at least a part of the near-infrared wavelength region on the base material, and each security part is provided with an overlapping part, and these overlapping parts are One or both of the security parts is a forgery prevention medium reading method in which gradation is applied from dark to light,
The reflectance of a specific wavelength in the two types of security units is measured in at least two lines using at least two types of light receiving elements, and authenticity determination is performed by comparing the measurement results. A method for reading an anti-counterfeit medium.   2. The method of reading a forgery prevention medium according to claim 1, wherein the light receiving portions of at least two types of light receiving elements for measuring the reflectance of the specific wavelength are adjacent to each other.   3. The method for reading a forgery prevention medium according to claim 1, wherein the light receiving portions of at least two types of light receiving elements for measuring the reflectance of the specific wavelength intersect each other.

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