JP2014223768A - Antifalsification medium and method for reading antifalsification medium - Google Patents

Abstract

An anti-counterfeit medium that performs anti-counterfeit determination by machine reading has high anti-counterfeiting and can improve the authenticity determination accuracy and a method for reading the anti-counterfeit medium.
A volume hologram layer having a reflection wavelength region in at least a part of a near infrared wavelength region on one surface of a substrate, and a near infrared light having a characteristic absorption in at least a part of the near infrared wavelength region. In the anti-counterfeit medium in which the absorption layers are sequentially laminated, the volume hologram layer is composed of at least two regions, and the at least two regions have different diffracted light reflection directions.
[Selection] Figure 11

Description

  The present invention relates to an anti-counterfeit medium and a method for reading an anti-counterfeit medium that perform 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.

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

  The problem to be solved by the present invention is to provide an anti-counterfeit medium and a forgery-preventing medium reading method that are highly difficult to counterfeit and can improve the accuracy of authenticity determination in an anti-counterfeit medium that performs authenticity determination by machine reading. It is to be.

  The anti-counterfeit medium according to claim 1 of the present invention is a volume hologram layer having a reflection wavelength region in at least a part of the near-infrared wavelength region, and at least a part of the near-infrared wavelength region on one surface of the substrate. In the anti-counterfeit medium in which near-infrared absorbing layers having absorption characteristic to the above are laminated in order, the volume hologram layer is composed of at least two regions, and the at least two regions have different diffracted light reflection directions. It is characterized by that.

  The anti-counterfeit medium according to claim 2 of the present invention is characterized in that the near-infrared absorbing layer is composed of at least two regions, and the at least two regions are absorption wavelength regions of different near-infrared wavelength regions. .

  In the anti-counterfeit medium according to claim 3 of the present invention, the region of the volume hologram layer in the different diffracted light reflection direction and the region of the absorption wavelength region of the different near-infrared wavelength region of the near-infrared absorption layer are adjacent to each other. And a plurality of them are arranged.

  According to a fourth aspect of the present invention, there is provided a method for reading an anti-counterfeit medium comprising: a light source that irradiates light having a plurality of wavelengths in the near-infrared wavelength region from a predetermined position to the anti-counterfeit medium according to the first or second aspect. In addition, the light receiving element is arranged in each of the different diffracted light reflection directions from the volume hologram layer, the reflectance is measured by each light receiving element, and the authenticity determination of the anti-counterfeit medium is performed from each measured value. It is characterized by performing.

  In the method for reading a forgery prevention medium according to claim 5 of the present invention, a light source for irradiating light of a plurality of wavelengths in the near-infrared wavelength region from a predetermined position is disposed on the forgery prevention medium according to claim 3, The forgery prevention medium is arranged in a direction in which a light receiving element is arranged in each of the different reflection directions of the diffracted light from the volume hologram layer, and the volume hologram layer and a plurality of regions arranged in the near infrared absorption layer are adjacent to each other. Measuring the increase / decrease in the reflectance of each light receiving element and comparing the output waveforms of the respective light receiving elements, the authenticity determination of the anti-counterfeit medium is performed.

  According to the present invention, a combination of a volume hologram having different diffracted light reflection directions and a security unit having a characteristic spectral waveform, and performing authenticity determination by reading a plurality of reflectances of feature points in space, In addition, the anti-counterfeit medium moves and measures the increase or decrease of the reflectivity in different diffracted light reflection directions, and compares the output waveform of each light receiving element, and makes anti-counterfeit judgment by machine reading It is possible to provide an anti-counterfeit medium and a forgery-preventing medium reading method that are highly difficult to counterfeit and can improve the accuracy of authenticity determination.

The conceptual diagram explaining the manufacturing method of the volume type hologram which concerns on embodiment of this invention. The conceptual diagram explaining the reading method of the volume type hologram shown in FIG. The conceptual diagram explaining the preparation methods of the volume hologram which differs in the reflection direction which concerns on embodiment of this invention. The conceptual diagram explaining the reading method of the volume type hologram from which the reflection direction shown in FIG. 3 differs. 4A and 4B are conceptual diagrams illustrating a method for reading a forgery prevention medium in which a plurality of regions according to an embodiment of the present invention are arranged, where FIG. 5A is a diagram viewed from the X direction, and FIG. 5B is a diagram viewed from the Z direction. The graph which shows the example of the brightness | luminance input of the sensor in embodiment. The graph which shows an example of the spectral characteristic of the volume type hologram layer which concerns on embodiment of this invention, and a near-infrared absorption layer. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram for explaining a method of reading a forgery prevention medium in which a plurality of areas according to an embodiment of the present invention are arranged in different directions; (a) a diagram viewed from an X direction, and (b) a diagram viewed from a Z direction. Figure. The graph which shows an example of the spectral characteristic of the volume type hologram layer which concerns on embodiment of this invention, and a near-infrared absorption layer. The graph which shows an example of the brightness | luminance measurement of the sensor in embodiment. The longitudinal section side view showing an example of the composition of the forgery prevention medium concerning the embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a conceptual diagram illustrating a volume hologram manufacturing method according to an embodiment of the present invention. A laser beam from a laser light source (not shown) is divided into a beam 10 and a beam 12, and the beam 10 is expanded by a lens 11 and irradiates the recording material 15 at an incident angle α. The beam 12 is expanded by a lens 13 and irradiates a diffusion plate 14. The light diffused by the diffusion plate 14 enters at an incident angle β from the opposite side of the recording material 15.

  FIG. 2 is a conceptual diagram illustrating a method for reading the volume hologram shown in FIG. The volume hologram 20 produced by recording the interference fringes on the recording material 15 in the arrangement shown in FIG. 1 has the diffusion plate 14 shown in FIG. 1 when illuminated by the light from the illumination light source 21 as shown in FIG. Reflected in the direction in which light exits from the position. The emission angle with the illumination light source 21 is α + β. Here, the intensity of the reflected light can be measured by arranging the sensor 22 at the emission position.

  By the way, the reproduction (reflection) wavelength in the volume hologram is basically the wavelength at which recording is performed unless the recording material is contracted and the pitch of the interference fringes is changed, so that it is reflected in the near infrared wavelength region. For this, a near-infrared laser is used.

  Further, depending on the recording material, there is a method of changing the pitch of the interference fringes. If a method of shifting the wavelength to the long wavelength side is employed, recording with a red laser is possible. Further, according to such a wavelength shift method, since the bandwidth of the reproduction wavelength tends to be widened, it is effective when it is desired to widen the bandwidth of the reflection wavelength.

  FIG. 3 is a conceptual diagram illustrating a method for producing a volume hologram having different reflection directions according to an embodiment of the present invention. A laser beam from a laser light source (not shown) is divided into a beam 30 and a beam 32. The beam 30 is expanded by a lens 31 and irradiates the recording material 35 at an incident angle α. The beam 32 is expanded by a lens 33 and irradiates a diffusion plate 34. Light diffused by the diffusion plate 34 enters perpendicularly from the opposite side of the recording material 35.

  FIG. 4 is a conceptual diagram illustrating a reading method of the volume hologram having different reflection directions shown in FIG. The volume hologram 40 produced by recording the interference fringes on the recording material 35 in the arrangement shown in FIG. 3 has the diffuser plate 34 shown in FIG. 3 when illuminated by the light from the illumination light source 21 as shown in FIG. Reflected in the direction in which light exits from the position. The illumination light source 21 has an arrangement equivalent to the positional relationship between the volume hologram 20 and the illumination light source 21 shown in FIG. 2, and the emission angle in FIG. Here, the intensity of the reflected light can be measured by arranging the sensor 41 at the emission position.

  FIG. 5 is a conceptual diagram illustrating a method for reading a forgery prevention medium in which a plurality of areas according to the embodiment of the present invention are arranged. The volume hologram 51 is formed by arranging a plurality of areas 51a to 51e having areas on the XY plane in the Y direction. The areas 51a, 51c, and 51e are areas where the reflected light is emitted in the direction shown in FIG. 4, and the areas 51b and 51d are areas where the reflected light is emitted in the direction shown in FIG. Next, the volume hologram 51 is irradiated by the illumination light source 21. At this time, the mask 50 is used so that only one of the plurality of regions of the volume hologram 51 is irradiated with illumination light.

  In the state shown in FIG. 5, since the illumination light is irradiated to the region 51 c, the reflected light from the region 51 c enters the sensor 41. Here, when the volume hologram 51 is moved in the Y-axis direction, illumination light is irradiated to another region. When moving so as to enter the region 51 b, the reflected light enters the sensor 22.

  FIG. 6 is a graph illustrating an example of luminance input of the sensor in the embodiment. The brightness | luminance input of the sensor 22 and the sensor 41 when making it move in the area | region 51a-the area | region 51e is shown.

  The sensor 22 has no luminance input in the area 51a and has an input in the area 51b. Further, there is no luminance input in the region 51c, there is input in the region 51d, and there is no input in the region 51e. That is, waveform data 60 as shown in FIG. 6 can be obtained by continuously moving the region 51a to the region 51e. Similarly, the waveform data 61 as shown in FIG. 6 can also be obtained by moving the sensor 41 in the areas 51a to 51e.

  FIG. 7 is a graph showing an example of spectral characteristics of the volume hologram layer and the near infrared absorption layer according to the embodiment of the present invention. The spectral curve 71 is a spectral curve of a volume hologram that reflects in the near-infrared wavelength region. The spectral curve 72 shows the spectral curve of the near-infrared absorbing layer A having characteristic absorption in the near-infrared wavelength region. Further, the spectral curve 73 shows a spectral curve of the near-infrared absorbing layer B having different characteristic absorption.

  FIG. 8 is a conceptual diagram illustrating a method for reading a forgery prevention medium in which a plurality of areas according to the embodiment of the present invention are arranged in different directions. The volume hologram 81 is obtained by arranging a region e to a region e having an area on the XY plane in the X direction. In the volume hologram 81, areas where reflected light is emitted are alternately arranged in the direction shown in FIG. 4 and the direction shown in FIG. The areas 81a, 81c, 81e are areas where the reflected light is emitted in the front direction shown in FIG. 4, and the areas 81b, 81d are areas where the reflected light is emitted in the oblique direction shown in FIG. The volume hologram 81 is irradiated by the illumination light source 82, the illumination light source 83, and the illumination light source 84 using the mask 80, and the reflected light from each region is read by the sensor 85 and sensor 86.

  Here, the moving direction of the volume hologram is different from that of the reading method shown in FIG. By moving in this direction, the change in the incident angle of the reproduction light incident on the volume hologram is small, the maximum value portion of the read waveform at the sensor becomes flat, and more stable reading can be realized. it can.

  Further, a near-infrared absorbing layer having characteristic absorption in the near-infrared wavelength region shown in FIG. 7 is provided on the front surface of the volume hologram 81, and the region 81a shows the spectral curve 72 of the near-infrared absorbing layer A as a region. Reference numeral 81c denotes a near-infrared absorbing layer having the characteristic of the spectral curve 73 of the near-infrared absorbing layer B.

  FIG. 9 is a graph showing an example of spectral characteristics of the volume hologram layer and the near infrared absorption layer according to the embodiment of the present invention. Since the volume hologram layer and the near-infrared absorbing layer are superposed and observed, the spectral curve that is actually sensed by the sensor is a combined spectral curve of these two spectra. The spectral curve 91 is a combination of the spectral curve 71 of the volume hologram layer shown in FIG. 7 and the spectral curve 72 of the near-infrared absorbing layer, and the spectral curve 92 is the spectral curve of the volume hologram layer shown in FIG. 71 and a spectral curve 73 of the near-infrared absorbing layer are synthesized.

  Here, the center wavelengths of the illumination light source 82, illumination light source 83, and illumination light source 84 in FIG. 8 are the center wavelength 93, center wavelength 94, and center wavelength 95 shown in FIG. The reading sensor 85 and sensor 86 are sensors having sensitivity at these three central wavelengths.

  Now, when observing with the illumination light source 82, the near-infrared absorption layer A has a reflectance of about 40% and the near-infrared absorption layer B has a reflectance of about 40% from the intersection of the center wavelength 93 and the spectral curve in FIG. Similarly, when observed with the illumination light source 83, the near-infrared absorbing layer A has a reflectance of about 90% and the near-infrared absorbing layer B has a reflectance of about 75%. Further, when observed with the illumination light source 84, the near-infrared absorbing layer A has a reflectance of about 90% and the near-infrared absorbing layer B has a reflectance of about 50%.

  FIG. 10 is a graph illustrating an example of luminance measurement of the sensor in the embodiment. In FIG. 8, the volume hologram 81 is illuminated with the illumination light source 82, illumination light source 83, and illumination light source 84, and the reflected light from each region is measured with the sensors 85 and 86 while moving from the region a to the region e. is there. A waveform 100 is a waveform that is illuminated by the light source 82 and measured by the sensor 85. A waveform 101 is a waveform similarly illuminated by the light source 82 and measured by the sensor 86.

  A waveform 102 is illuminated by the light source 83 and measured by the sensor 85, and a waveform 103 is a waveform measured by the sensor 86. A waveform 104 is illuminated by the light source 84 and is measured by the sensor 85, and a waveform 105 is a waveform measured by the sensor 86.

  Here, the portions to be focused on in these waveforms are the maximum luminance values in the regions a and c. The illumination light source 82 is 50% for both, the illumination light source 83 is 90% for the region a, and 75% for the region c. Further, in the illumination light source 84, the area a is 90% and the area c is 50%.

  By reading out the feature points of these waveforms, it is possible to determine authenticity. Furthermore, by providing a near-infrared absorbing layer in another region, providing a near-infrared absorbing layer with a different spectral curve, changing the reflection direction, reflection angle, and combination of volume holograms, and increasing More complex waveforms can be created, and by comparing these waveforms to determine authenticity, a more accurate authenticity determination can be performed, and at the same time, a forgery prevention medium that is very difficult to counterfeit is obtained.

  FIG. 11 shows an example of the configuration of the forgery prevention medium according to the embodiment of the present invention. The anti-counterfeit medium 96 is provided with a volume hologram 98 on at least a part of one surface of a base 97, and a near-infrared absorbing layer 99 having a characteristic absorption in at least a part of the near-infrared wavelength region on the upper surface. Is provided.

  The anti-counterfeit medium and the anti-counterfeit medium reading method of the present invention combine volume holograms with different diffracted light reflection directions and a security part having a characteristic spectral waveform, and provide a plurality of reflectances of feature points in space. Authenticity determination is performed by reading, and further, the medium moves, and the increase / decrease in reflectivity in different diffracted light reflection directions is detected, and the output waveform of each sensor is compared, thereby increasing the accuracy of true / false determination. It can be improved.

  10, 12, 30, 32 ... beam, 11, 13, 31, 33 ... lens, 14, 34 ... diffuser plate, 15, 35 ... recording material, 20, 40, 51, 81, 98 ... volume hologram, 21, 82, 83, 84 ... illumination light source, 22, 41, 85, 86 ... sensor, 50, 80 ... mask, 51a, 51b, 51c ... area, 51d, 51e ... area, 81a, 81b, 81c ... area, 81d, 81e ... Area, 96 ... Anti-counterfeit medium, 97 ... Base material, 99 ... Near infrared absorbing layer, [alpha], [beta] ... Incident angle.

Claims (5)

On one surface of the substrate, a volume hologram layer having a reflection wavelength region in at least part of the near infrared wavelength region, and a near infrared absorption layer having characteristic absorption in at least part of the near infrared wavelength region in order In the anti-counterfeit medium that is laminated,
The volume type hologram layer includes at least two regions, and the at least two regions have different diffracted light reflection directions.   The anti-counterfeit medium according to claim 1, wherein the near-infrared absorption layer includes at least two regions, and the at least two regions are absorption wavelength regions having different near-infrared wavelength regions.   A plurality of regions of the volume hologram layer having different reflection directions of diffracted light and a region of the absorption wavelength region of the different near-infrared wavelength region of the near-infrared absorption layer are arranged adjacent to each other. The forgery prevention medium according to claim 2.   A light source that irradiates light of a plurality of wavelengths in the near-infrared wavelength region from a predetermined position to the anti-counterfeit medium according to claim 1 or 2, and different diffracted light reflections from the volume hologram layer A method for reading an anti-counterfeit medium, characterized in that a light-receiving element is arranged in each direction, the reflectance is measured by each of the light-receiving elements, and the authenticity of the anti-counterfeit medium is determined from each measured value.   A light source for irradiating light of a plurality of wavelengths in the near-infrared wavelength region from a predetermined position to the anti-counterfeit medium according to claim 3, and receiving light in different diffracted light reflection directions from the volume hologram layer. While arranging the element, moving the anti-counterfeit medium in a direction in which the volume hologram layer and the plurality of regions arranged in the near-infrared absorbing layer are adjacent to each other, the light receiving element increases or decreases the reflectance. An anti-counterfeit medium reading method characterized in that the anti-counterfeit medium is determined by measuring and comparing the output waveforms of the respective light receiving elements.

Images