JP5929092B2 - Identification device - Google Patents

Description

  The present invention relates to an identification device for an identification medium that can be identified by emitting infrared phosphors, and more particularly, to an identification device including means for irradiating visible light for recognizing a measurement position.

  Anti-counterfeiting media such as securities, cards and passports, valuable printed materials such as driver's licenses, passports and insurance cards, and anti-counterfeiting media such as stickers that certify articles as authentic Therefore, it is required to always incorporate a new anti-counterfeiting technique, and a true / false discrimination method capable of determining whether or not the product is genuine is required.

  In the anti-counterfeiting technology, micro characters, copy check patterns, infrared absorbing ink, fluorescent light emitting ink, or the like is used in order to enhance security. Among the above-described techniques, fluorescent light-emitting inks are inks that are difficult to visually recognize under normal visible light and that can be detected visually or with a detector by irradiating ultraviolet rays or infrared rays. .

  In this type of fluorescent ink, a fluorescent pigment is used in place of a colored organic pigment or inorganic pigment having absorption in the visible light region used for a normal printing ink. Other components of the fluorescent ink include vehicles and adjuvants. The fluorescent light-emitting ink can form a fluorescent printing portion by a known printing method such as normal offset printing.

  In order to cause the fluorescent printing unit to emit light, excitation light is irradiated. By irradiating the excitation light, the phosphor of the fluorescent print absorbs the excitation light and emits fluorescence. This fluorescence can be confirmed as a fluorescent mark visually or using a detector. Phosphors that emit visible light are generally used and can be visually confirmed. On the other hand, printed materials using phosphors that emit infrared rays are identified by a detection device, and security is given (see Patent Document 1).

  However, the excitation light for causing these infrared fluorescent printing parts to emit light is infrared light, and there is an advantage that it is difficult to be noticed by general consumers and those who try to counterfeit or imitate. Since it cannot be seen, there is a problem that it is difficult to perform the detection work. In particular, unlike an apparatus for confirming the fluorescence of visible light, it is difficult to determine where the light is radiated, and the distance between the identification device and the identification medium must be provided very close (see Patent Document 2). .

Japanese Patent No. 3069669 JP-A-4-255084

  The present invention has been made in view of the above circumstances, and by providing two light projecting means for irradiating light, it is possible to easily identify even if the distance between the identification device and the identification medium is long, especially the infrared region and visible light. It is an object of the present invention to provide an identification device that can be easily identified by including two light projecting means for irradiating light of a region.

The invention according to claim 1 is an apparatus for identifying a mark including a phosphor having an excitation wavelength peak in an infrared region, wherein the mark is irradiated with at least excitation light of the phosphor. Means, a second light projecting means for irradiating visible light, and a light receiving means for detecting fluorescence emitted corresponding to the first light projecting means, and the light of the first light projecting means, and light of the second light projecting means condensed to measure the position of the mark, and the fluorescence emitted from the mark to the light receiving means a condenser to order lenses, the first Both the light projecting means and the second light projecting means can irradiate the lens with light, and the light receiving means includes the lens at a position where the fluorescence passing through the lens can be detected. Features.

The invention according to claim 2 is an apparatus for identifying a mark including a phosphor having at least two excitation wavelength peaks of an infrared region and a visible light region, wherein excitation light in the infrared region of the phosphor is applied to the mark. At least a first light projecting means for irradiating and a second light projecting means for irradiating excitation light in the visible light region are provided, and the light is emitted corresponding to the first light projecting means and the second light projecting means. A light receiving means for detecting fluorescence, condensing the light from the first light projecting means and the light from the second light projecting means at the measurement position of the mark , and from the mark to the light receiving means. the released the fluorescence a condenser to order the lens, it is possible to irradiate light to the first light projecting means and the both the lens of the second light emitting means, said light receiving means at a position capable of detecting the fluorescence through the lens Characterized in that it comprises a serial lens.

According to the present invention, the following effects can be obtained.
That is, according to the inventions according to the claim 1, with respect to mark the excitation light includes a fluorescent material is an infrared region, in addition to the light emitting means for identifying device for irradiating excitation light for exciting By providing a means for irradiating visible light, it becomes possible to know the position where the excitation light is irradiated, and at the same time, the position where the excitation light is irradiated can be known even if there is a certain distance, so that it is easy to identify. .
In addition, since the identification device includes a lens for condensing the light of the first light projecting unit and the light of the second light projecting unit at the measurement position of the mark, the light of the two light projecting units is The point where the light is condensed can be known, and the optimum position of the distance between the mark and the identification device can also be known, so that the detection sensitivity can be further improved.

Further, according to the inventions according to the claim 2 for mark comprising a phosphor having at least two peaks of the excitation wavelength in the infrared region and the visible light region, irradiated with excitation light in the infrared region of the phosphor In addition to the first light projecting means, by providing the second light projecting means for irradiating the excitation light in the visible light region, the position where the excitation light is irradiated can be known, and it becomes easier to identify, Since visible light is also excitation light, excitation energy increases and light emission increases, so identification is possible even if there are few phosphors contained in the mark, and identification is possible even if the sensitivity of the detector is poor. The effect of facilitating identification can be obtained.
In addition, since the identification device includes a lens for condensing the light of the first light projecting unit and the light of the second light projecting unit at the measurement position of the mark, the light of the two light projecting units is The point where the light is condensed can be known, and the optimum position of the distance between the mark and the identification device can also be known, so that the detection sensitivity can be further improved.

It is the schematic for demonstrating one Embodiment of the identification device of this invention. It is explanatory drawing for demonstrating the inside of one Embodiment of the identification medium of FIG. It is explanatory drawing for demonstrating the inside of one Embodiment of the identification medium of FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram for explaining an embodiment of the identification apparatus of the present invention, and FIG. 2 is an explanatory diagram for explaining the inside of one embodiment of the identification medium of FIG. FIG. 3 is an explanatory diagram for explaining the inside of an embodiment of the identification medium different from FIG.

  The identification medium 12 detected by the identification device 11 according to the embodiment of the present invention is provided with a mark 13 including a phosphor that emits light when irradiated with light having an excitation wavelength, and the identification device 11 detects this. Is. The phosphor identified by the identification device 11 according to the embodiment of the present invention has an excitation spectrum peak at least in the infrared region. Furthermore, it is more desirable to have a small excitation spectrum peak in the visible light region. The emission wavelength is either UV-visible or infrared, and the near-infrared region is desirable. Further, although it is desirable that there are different wavelength regions for the excitation wavelength and the emission wavelength, they may be the same.

  Fluorescence is a substance that emits energy when absorbed, and is a substance that absorbs light (ultraviolet / visible light) energy and emits light. Light has energy represented by E = hν (E: energy, h: Planck's constant, ν: frequency). When light hits a substance, the energy of the light may be absorbed by the substance, and the substance that is in a stable energy state (ground state) due to energy absorption temporarily becomes a high energy state (excited state). Become. The substance then releases energy and tries to return to a stable ground state. At this time, the phenomenon in which the energy of the difference is emitted as light instead of heat is referred to as light emission. In many substances, a part of the absorbed energy is emitted as thermal energy, so that light having a longer wavelength than that of the absorbed light is generated, but some light having a shorter wavelength is generated.

  Luminescence by light stimulation includes fluorescence and phosphorescence, but is sometimes referred to as fluorescence as a major conclusion. In the present invention, it is also described as fluorescence including phosphorescence. In fluorescence, part of the absorbed energy is released as heat and the remaining energy is released as light. On the other hand, heat is similarly emitted in the case of phosphorescence. At this time, an intersystem crossing occurs, and the phenomenon in which light cannot be returned to the ground state immediately and continues to emit light is phosphorescence. In most cases, fluorescence is emitted on the order of nanoseconds, and phosphorescence is emitted on the order of microseconds to milliseconds. When a substance absorbs ultraviolet and visible light, an electronic transition occurs. These electrons have a spin direction, and there is a rule that two electrons exist in opposite directions (Pauli's exclusion principle). In normal excitation, the spin direction remains reversed, but in the case of phosphorescence, intersystem crossing occurs, the spins are in the same direction, and cannot return to the ground state as it is, and it takes time to return to the ground state. It is such a thing.

Examples of the phosphor include sulfide phosphors (ZnS, CaS). As an example, calcium sulfide is used as a base, and samarium (Sm) and europium (Er) are added as activators. In addition, a mixture of alkaline earth sulfides containing bismuth and samarium as an activator, a mixture of magnesium sulfide and strontium sulfide (Mg _x Sr _1-x S), and magnesium and strontium were mixed. Things.

  The mark 13 including the phosphor is preferably offset printing, flexographic printing, gravure printing, ink jet printing, screen printing, or pad printing, but may be provided by other printing methods, or by using a transfer machine or a laminating machine. Can be provided.

  The identification device 11 of the present invention is a device that identifies the mark 13 including the phosphor of the identification medium 12 described above. The identification device 11 includes a first light projecting unit 1 and a second light projecting unit 2 for irradiating a mark 13 including a phosphor, and the attached lens 5 emitted from the first light projecting unit 1 is attached. The light receiving means 3 for detecting the light emitted from the mark 13 including the fluorescent light emitted by the passing light 21 and the fluorescent light emitted by the second light projecting means 2 and irradiated through the attached lens 6 is provided. .

  The first light projecting means 1 is for irradiating the excitation wavelength in the infrared region of the phosphor in order to identify the mark 13 including the phosphor of the identification medium 12, and is preferably a near-infrared LED. However, it irradiates light including an excitation wavelength of a light emitter such as a laser or an incandescent lamp. The first light projecting means 1 is provided with a lens 5 attached thereto. On the other hand, the second light projecting means 2 is for recognizing the position irradiated by the first light projecting means 1 and is preferably a visible light LED, but a visible light such as a laser, an incandescent light, a fluorescent light or the like. What is necessary is just to be able to irradiate light.

  The lens 5 is for condensing infrared light irradiated by the first light projecting means 1 and may be another lens as long as it can condense. The lens 6 is also for condensing visible light irradiated by the second light projecting means 2 and may be another lens as long as it can condense. The distance and the position may be set so that the lens 5 and the lens 6 are condensed at the same distance. When an LED is used as the light projecting means, a bullet-type LED is used, and the bullet-type epoxy portion of the LED becomes the lens 5 and the lens 6, which is a preferable form. The first light projecting means 1 and the second light projecting means 2 may irradiate continuous light or pulse light.

  In order to overlap the positions where the infrared irradiation light 21 irradiated from the lens 5 and the visible irradiation light 22 irradiated from the lens 6 are in focus, as shown in FIG. It is important that the first and second light projecting means 2, the lens 5 and the lens 6 are arranged. When conditions other than the wavelengths of the first light projecting means 1 and the second light projecting means 2 are the same, and when using lenses having the same condition that collect light at the same distance, the measurement position, that is, the lens The distances 23 from the identification medium to the identification medium need to be the same. You may arrange | position at the same height at the same angle. In addition, when the light projecting unit and the lens are different from each other, the present invention is not limited to this.

  The mark 13 including the phosphor of the identification medium 12 excited by the irradiation light 21 and the irradiation light 22 emits light. The emitted light passes through the optical filter 4 and reaches the light receiving element 3. The optical filter 4 is for transmitting light having a wavelength to emit light, for disturbing disturbance, and if necessary, blocking the irradiation light 21 and the irradiation light 22. A long-pass filter that transmits light having a wavelength longer than an arbitrary wavelength and blocks light shorter than that is desirable, but another filter such as a band-pass filter may be used.

  The light receiving means 3 may be anything that receives and discriminates light in the infrared region, and is preferably a light receiving element that receives infrared light and converts it into an electrical signal, or a Si photodiode. For example, the light received by the light receiving element is converted into an electric signal, and the intensity is displayed on the output display unit 32. An intensity higher than the blank emission intensity is determined as a determination value in advance, and if the value of the output display unit 32 exceeds the determination value, the circuit is designed so that the determination lamp 33 is lit. This output display may be performed by the output display unit 32 and / or the determination lamp 33. The light receiving means 3 may be an infrared camera or another device. In the case of an infrared camera, since the light emitting portion becomes white, it is possible to make a visual decision or to perform an image processing. Either the identification device 11 or the identification medium 12 may be moved and read in a linear form, or the code may be read, or a two-dimensional code may be read using an infrared camera.

  A lens 5 attached to the first light projecting means 1, a lens 6 used for the second light projecting means 2, and a lens 7 for narrowing the irradiation light of the first light projecting means 1 and the second light projecting means 2. These are desirably convex lenses that are optical elements for refracting and converging light. As the distance from the axis increases with the rotationally symmetric transparent material, the light can be gathered if the shape is inclined so as to be refracted inward, that is, the center is thicker than the edge. This rotationally symmetric axis is called the optical axis, and light rays parallel to the optical axis gather at one point after passing through the lens. This point is called the focus.

  As shown in FIG. 3, the irradiation light 21 emitted from the lens 5 and the irradiation light 22 emitted from the lens 6 may overlap with each other through a common lens 7. In this case, light emission from the mark 13 including the phosphor of the identification medium 12 can also be detected through the lens 7.

  Specific examples of the present invention will be described below.

<Example 1>
First, screen printing was performed on high-quality paper with an ink containing a phosphor, put in a dryer at 80 ° C., and dried, provided with a mark containing a phosphor having a thickness of 10 μm to obtain an identification medium.

[Composition of ink containing phosphor]
Phosphor (NdNaP ₄ O ₁₂ ) 25 parts by weight
25 parts by weight of vinyl chloride
30 parts by weight of cyclohexanone
20 parts by weight of isophorone
The identification medium obtained above was read using the identification device shown in FIG. As shown in FIG. 2, as the irradiation means 1, an infrared ray was emitted from an LED emitting an infrared ray having a central wavelength of 780 nm as an excitation wavelength, and a lens for focusing at 50 mm away was attached thereto. On the other hand, a lens that irradiates with an LED that emits visible light having a center of 450 nm as the irradiation means 2 and also focuses at a position 50 mm away is attached. The infrared LED was installed with an inclination of 30 degrees from the vertical direction. Further, the visible light LED is tilted 30 degrees from the vertical direction, irradiated from a direction different from the infrared LED, and placed at the same height as the infrared LED, thereby condensing at the same position. An infrared camera was installed in the vertical direction of the condensed position, and a long-pass filter for transmitting light of 850 nm or more and blocking light of about 850 nm or less was placed in front of the infrared camera.

<Example 2>
In Example 1, the identification device used was changed to an LED that emits visible light having a central wavelength of 580 nm as the irradiating means 2, and the identification medium was read in the same manner as in Example 1 except for this. .

<Comparative example>
In the identification apparatus of Example 1, the identification medium was read in the same manner as in Example 1 except that the visible light LED was not irradiated.

In Example 1, Example 2, and Comparative Example, the identification medium was read five times without looking at the result. For Example 1 and Example 2, the measurement position was immediately known, and the time required for preparation for measurement per measurement was short, but it was not known where the measurement was performed for the comparative example. It took time to prepare and measure while guessing the direction of light. The results of the emission intensity are shown in Table 1.

  As is clear from Table 1, from the measurement results of Example 1 and Example 2 and the comparative example, it is only Example 1 and Example 2 that can be stably read. In the comparative example, the reading direction and distance are appropriate. Because of this, accurate reading is not possible. It was found that the identification device of Example 1 was superior in reading light emission because the reading time was faster and the light emission was accurately captured than the comparative example. Further, in Example 2, the emission intensity greater than that in Example 1 could be measured.

  DESCRIPTION OF SYMBOLS 1 ... 1st light projection means, 2 ... 2nd light projection means, 3 ... Light-receiving means, 4 ... Optical filter, 5 ... Lens attached to 1st light projection means, 6 ... 2nd light projection means Attached lens, 7... Lens for narrowing the irradiation light of the first light projecting means and the second light projecting means, 11... Identifying device, 12... Identifying medium, 13. Light emitted by the light means, 22... Light emitted by the second light projecting means 2, 23... Distance from the lens to the identification medium, 31... Power switch, 32.

Claims (2)

An identification apparatus for a mark including a phosphor having an excitation wavelength peak in an infrared region, wherein the mark is irradiated with at least first light projecting means for irradiating at least excitation light of the phosphor and visible light. A second light projecting means; and a light receiving means for detecting fluorescence emitted corresponding to the first light projecting means,
Condensed by the light in the measurement position of the mark of light and the second light projecting means of the first light emitting means, and, you condensing the fluorescence emitted from the mark to the light receiving means The first light projecting unit and the second light projecting unit can irradiate the lens with light, and the light receiving unit can detect the fluorescence passing through the lens. An identification device comprising the lens at a position. A mark identifying device including a phosphor having at least two excitation wavelength peaks in an infrared region and a visible light region, wherein the mark is irradiated with excitation light in the infrared region of the phosphor. And at least second light projecting means for irradiating excitation light in the visible light region, and light receiving means for detecting fluorescence emitted corresponding to the first light projecting means and the second light projecting means, Prepared,
Condensed by the light in the measurement position of the mark of light and the second light projecting means of the first light emitting means, and, you condensing the fluorescence emitted from the mark to the light receiving means The first light projecting unit and the second light projecting unit can irradiate the lens with light, and the light receiving unit can detect the fluorescence passing through the lens. An identification device comprising the lens at a position.

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