WO2012018085A1

WO2012018085A1 - Light-emitting medium and method for confirming light-emitting medium

Info

Publication number: WO2012018085A1
Application number: PCT/JP2011/067879
Authority: WO
Inventors: 陽子関根; 山本　学; 北村　満; 山内　豪; 明子北村; 桜子羽鳥
Original assignee: 大日本印刷株式会社
Priority date: 2010-08-04
Filing date: 2011-08-04
Publication date: 2012-02-09
Also published as: JP2012051356A

Abstract

[Problem] To provide a light-emitting medium that is capable of easily and quickly distinguishing between whether or not marketable security or the like has been falsified. [Solution] The light-emitting medium (10) that configures a marketable security has a light-emitting image (12). This light-emitting image (12) has: a first region that is formed on a substrate (11) using a first fluorescent ink (13) containing first fluorescent bodies; and a second region that is formed on the substrate (11) using a second fluorescent ink (14) containing second fluorescent bodies. Of these, the first fluorescent bodies of the first fluorescent ink (13) comprise fluorescent bodies that emit blue light when irradiated by UV-A, and that emit red light when irradiated by UV-C. Also, the second fluorescent bodies of the second fluorescent ink (14) comprise fluorescent bodies that emit visually confirmed light as light that is the same color as the blue light or the red light when irradiated by UV-A.

Description

Luminescent medium and method for confirming luminous medium

The present invention relates to a light-emitting medium having a light-emitting image that appears when invisible light within a specific wavelength region is irradiated. The present invention also relates to a method for confirming the light emitting medium.

In recent years, micro characters, copy check patterns, infrared absorbing inks have been used to enhance security in media that require prevention of counterfeiting, such as securities including gold vouchers and prepaid cards, and identification cards including licenses. Alternatively, fluorescent ink is used. Among them, the fluorescent ink is an ink containing a phosphor that is hardly visible under visible light but is visible when invisible light such as ultraviolet rays or infrared rays is irradiated. By using such a fluorescent ink, it is possible to form a fluorescent image or a luminescent image that appears only when invisible light within a specific wavelength region is irradiated on securities. As a result, it is possible to prevent the securities from being easily forged by a general-purpose color printer or the like.

Further, in order to further enhance the effect of preventing forgery, it has been proposed to form a luminescent image that cannot be visually recognized by the naked eye on a securities by using fluorescent ink. For example, Patent Document 1 discloses a medium having a luminescent image formed using a first fluorescent ink and a second fluorescent ink. In this case, the first fluorescent ink and the second fluorescent ink are visually recognized as the same color under visible light and ultraviolet light when viewed with the naked eye, and are different from each other when viewed through the determination tool. The ink is visible as a color. For this reason, the luminescent image formed in the securities is not easily counterfeited, and this enhances the counterfeit prevention effect by the fluorescent ink.

Japanese Patent No. 4188881

It is preferable that the procedure for determining whether the securities are counterfeited is carried out simply and quickly. Therefore, there is a need for a medium that can easily and quickly determine whether securities are forged by the naked eye without using a tool such as a determination tool.

An object of the present invention is to provide a light-emitting medium that can effectively solve such problems and a method for confirming the light-emitting medium.

The present invention relates to a luminescent medium having a luminescent image on a substrate, wherein the luminescent image has a first region containing a first phosphor and a second region containing a second phosphor, and a pattern region 20. And the background region 25, when invisible light in the first wavelength region is irradiated, the first phosphor and the second phosphor emit light of a color visually recognized as the same color, and the second wavelength When the invisible light in the region is irradiated, the first region and the second region are visually recognized as regions having different colors.

In the light emitting medium according to the present invention, when invisible light in the first wavelength region is irradiated, the first phosphor emits light of the first color, and the second phosphor emits the first color or the first color. When the light of the color visually recognized as the same color is emitted and invisible light in the second wavelength region is irradiated, the first phosphor emits light of the second color, and the second phosphor The first region and the second region may be visually recognized as different color regions by emitting light of the third color or not emitting light.

In the light emitting medium according to the present invention, when invisible light in the first wavelength region is irradiated, the first phosphor emits light of the first color, and the second phosphor emits the first color or the first color. When the light of the color visually recognized as the same color is emitted and the invisible light in the second wavelength region is irradiated, the first phosphor has the color visually recognized as the first color or the same color as the first color. The second phosphor emits light of a third color, or does not emit light, and the first region and the second region are visually recognized as different color regions. It may be.

In the light emitting medium according to the present invention, when the second phosphor is irradiated with invisible light in the first wavelength region, the second phosphor emits light of a color visually recognized as the first color or the same color as the first color, and the second phosphor. It may be made of a phosphor that emits light of the third color when irradiated with invisible light within the wavelength region.

In the light emitting medium according to the present invention, when the second phosphor is irradiated with invisible light in the first wavelength region, the second phosphor emits light of a color visually recognized as the first color or the same color as the first color, and the second phosphor. It may be made of a phosphor that does not emit light when irradiated with invisible light in the wavelength region.

In the light emitting medium according to the present invention, when invisible light in the first wavelength region is irradiated, the color of light emitted from the first phosphor, the color of light emitted from the second phosphor, Is preferably 10 or less, more preferably 3 or less.

In the light emitting medium according to the present invention, the first region and the second region may be formed from the first phosphor and the second phosphor provided in the same predetermined pattern, respectively.

In the light emitting medium according to the present invention, at least a part of the second region may be adjacent to the first region.

In the light emitting medium according to the present invention, the first region has at least one first pattern region including the first phosphor, and the second region includes at least one second pattern including the second phosphor. There may be a region, and the first pattern region and the second pattern region may be arranged independently of each other.

The shape of the first pattern region may be substantially the same as the shape of the second pattern region.

The present invention provides a method for confirming a luminescent medium having a luminescent image on a substrate, the step of preparing the luminescent medium described above, and irradiating the luminescent medium with invisible light in a first wavelength region. Confirming that the first region and the second region are not discriminated, and irradiating the light emitting medium with invisible light in the second wavelength region to discriminate between the first region and the second region of the luminescent image. And a process to confirm

The luminescent medium according to the present invention has a luminescent image on a substrate. The luminescent image has a first region including the first phosphor and a second region including the second phosphor. Here, when invisible light in the first wavelength region is irradiated, the first phosphor and the second phosphor emit light having a color that is visually recognized as the same color. Further, when invisible light in the second wavelength region is irradiated, the first region and the second region are visually recognized as regions of different colors. As a result, it is possible to easily and quickly confirm the emission image.

FIG. 1 is a plan view showing an example of securities constituted by an anti-counterfeit medium comprising a light emitting medium of the present invention. FIG. 2 is a plan view showing a light emission image of the forgery prevention medium in the first embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line III-III of the luminescent image shown in FIG. FIG. 4A is a diagram showing a fluorescence emission spectrum of the first fluorescent ink according to the first embodiment of the present invention. FIG. 4B is a diagram showing a fluorescence emission spectrum of the second fluorescent ink according to the first embodiment of the present invention. FIG. 5 is an xy chromaticity diagram showing the chromaticity of fluorescence emitted from the first fluorescent ink and the second fluorescent ink in the first embodiment of the present invention. FIG. 6A is a plan view showing a light emission image when UV-A is irradiated in the first embodiment of the present invention. FIG. 6B is a plan view showing a light emission image when UV-C is irradiated in the first embodiment of the present invention. FIG. 7 is a plan view showing a light emission image of a forgery prevention medium in a modification of the first embodiment of the present invention. FIG. 8 is a cross-sectional view taken along the line VIII-VIII of the luminescent image shown in FIG. FIG. 9A is a plan view showing a light emission image when UV-A is irradiated in the modification of the first embodiment of the present invention. FIG. 9B is a plan view showing a light emission image when UV-C is irradiated in the modification of the first embodiment of the present invention. FIG. 10 is a diagram showing a fluorescence emission spectrum of the second fluorescent ink according to the second embodiment of the present invention. FIG. 11A is a plan view showing a light emission image when UV-A is irradiated in the second embodiment of the present invention. FIG. 11B is a plan view showing a light emission image when UV-C is irradiated in the second embodiment of the present invention. FIG. 12A is a diagram showing a fluorescence emission spectrum of the first fluorescent ink according to the third embodiment of the present invention. FIG. 12B is a diagram showing a fluorescence emission spectrum of the second fluorescent ink according to the third embodiment of the present invention. FIG. 13 is an xy chromaticity diagram showing the color of fluorescence emitted from the first fluorescent ink and the second fluorescent ink in the third embodiment of the present invention. FIG. 14A is a plan view showing a light emission image when UV-C is irradiated in the third embodiment of the present invention. FIG. 14B is a plan view showing a light emission image when UV-A is irradiated in the third embodiment of the present invention. FIG. 15 is a plan view showing a light emission image of a forgery prevention medium in the fourth embodiment of the present invention. 16 is a cross-sectional view taken along line XVI-XVI of the luminescent image shown in FIG. FIG. 17A is a plan view showing a light emission image when UV-A is irradiated in the fourth embodiment of the present invention. FIG. 17B is a plan view showing a light emission image when UV-C is irradiated in the fourth embodiment of the present invention. FIG. 18 is a plan view showing a light emission image of a forgery prevention medium in a modification of the fourth embodiment of the present invention. FIG. 19 is a plan view showing a light emission image when UV-C is irradiated in the fifth embodiment of the present invention. FIG. 20A is a plan view showing a light emission image when UV-C is irradiated in the sixth embodiment of the present invention. FIG. 20B is a plan view showing a light emission image when UV-A is irradiated in the sixth embodiment of the present invention.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 6B. First, the whole forgery prevention medium 10 made of the light emitting medium of the present invention will be described with reference to FIGS.

Anti-Counterfeit Medium FIG. 1 is a diagram showing an example of a securities such as a gift certificate composed of an anti-counterfeit medium 10 according to the present embodiment. As shown in FIG. 1, the anti-counterfeit medium 10 includes a base material 11 and a luminescent image 12 formed on the base material 11. In the present embodiment, as will be described later, the light emission image 12 functions as an authenticity determination image for determining the authenticity of the forgery prevention medium 10. As shown in FIG. 1, the luminescent image 12 includes a pattern area (first area) 20 and a background area (second area) 25 formed adjacent to the pattern area 20. In the example shown in FIG. 1, the pattern area 20 is composed of a pattern made up of characters “A”, and the background area 25 is formed so as to surround the pattern area 20. Each area |

region

20 and 25 is formed by printing the fluorescent ink which is excited by invisible light and emits fluorescence so that it may mention later.

The material of the base material 11 used in the anti-counterfeit medium 10 is not particularly limited, and is appropriately selected according to the type of securities constituted by the anti-counterfeit medium 10. For example, white polyethylene terephthalate having excellent printability and processability is used as the material of the substrate 11. The thickness of the base material 11 is appropriately set according to the type of securities constituted by the forgery prevention medium 10.

The size of the luminescent image 12 is not particularly limited, and is appropriately set according to the ease of authenticity determination and the required determination accuracy. For example, the lengths l ₁ and l ₂ of the luminescent image 12 are in the range of 1 to 210 mm and 1 to 300 mm, respectively.

Emission Image Next, the emission image 12 will be described in more detail with reference to FIGS. 2 is an enlarged plan view showing the luminescent image 12 under visible light, and FIG. 3 is a cross-sectional view taken along the line III-III of the luminescent image 12 shown in FIG.

First, the structure of the luminescent image 12 will be described with reference to FIG. As shown in FIG. 3, the pattern area 20 and the background area 25 of the luminescent image 12 are formed by solid-printing the first fluorescent ink 13 and the second fluorescent ink 14 on the substrate 11.

FIG. 3 shows an example in which the first fluorescent ink 13 in the pattern area 20 and the second fluorescent ink 14 in the background area 25 are in contact with each other. However, the present invention is not limited to this, and a gap that cannot be visually recognized by the naked eye is formed between the first fluorescent ink 13 in the pattern area 20 and the second fluorescent ink 14 in the background area 25. Good. Further, the first fluorescent ink 13 in the pattern area 20 and the second fluorescent ink 14 in the background area 25 may overlap each other. Note that “the background region 25 is adjacent to the pattern region 20” not only means that the pattern region 20 and the background region 25 are in contact with each other, but also a gap that cannot be visually recognized by the naked eye. The concept includes a state formed between the region 25 and a state where the pattern region 20 and the background region 25 are overlapped.

The thicknesses t ₁ and t ₂ of the first fluorescent ink 13 and the second fluorescent ink 14 are appropriately set according to the type of securities, the printing method, etc. For example, the thickness t ₁ is 0.3 to 100 μm. The thickness t ₂ is in the range of 0.3 to 100 μm. Incidentally, preferably, the thickness t ₁ and the thickness t ₂ is almost the same. As a result, the boundary between the pattern area 20 and the background area 25 due to the difference between the thickness of the first fluorescent ink 13 and the thickness of the second fluorescent ink 14 can be suppressed.

As will be described later, each of the first fluorescent ink 13 and the second fluorescent ink 14 includes a predetermined phosphor that does not emit light under visible light but emits light under specific invisible light, for example, a granular pigment. Here, the particle size of the pigment contained in the

inks

13 and 14 is, for example, in the range of 0.1 to 10 μm, and preferably in the range of 0.1 to 3 μm. For this reason, when visible light is irradiated to the

inks

13 and 14, the light is scattered by the pigment particles. Therefore, when the luminescent image 12 is viewed under visible light, as shown in FIG. 2, the white picture area 21 a is visually recognized as the picture area 20 and the white background area 26 a is visually recognized as the background area 25. Further, as described above, the base material 11 in the present embodiment is formed from white polyethylene terephthalate. For this reason, under visible light, the base material 11, the pattern area 20 and the background area 25 of the luminescent image 12 are all visually recognized as white. Therefore, the pattern of the pattern area 20 of the luminescent image 12 does not appear under visible light. This prevents the forgery prevention medium 10 having the luminescent image 12 from being easily forged.
In FIG. 2, the first boundary line 15 a between the pattern area 20 and the background area 25 and the second boundary line 15 b between the base material 11 and the luminescent image 12 are drawn for convenience. is there. Under visible light, the first boundary line 15a or the second boundary line 15b is not actually visually recognized.

Fluorescent ink Next, the first fluorescent ink 13 and the second fluorescent ink 14 will be described in more detail with reference to FIGS. 4A to 5. FIG. 4A is a diagram illustrating a fluorescence emission spectrum of the first fluorescent ink 13, and FIG. 4B is a diagram illustrating a fluorescence emission spectrum of the second fluorescence ink 14. FIG. 5 is an xy chromaticity diagram showing the chromaticity of light emitted from the first fluorescent ink 13 and the second fluorescent ink 14 in the XYZ color system when light in a specific wavelength region is irradiated.

(First fluorescent ink)
First, the first fluorescent ink 13 will be described. In FIG. 4A, the alternate long and short dash line indicates the fluorescence emission spectrum of the first fluorescent ink 13 when irradiated with ultraviolet light, which is invisible light in the wavelength region of 315 to 400 nm (within the first wavelength region), so-called UV-A. The solid line shows the fluorescence emission spectrum of the first fluorescent ink 13 when irradiated with ultraviolet light, which is invisible light in the wavelength region of 200 to 280 nm (in the second wavelength region), so-called UV-C. ing. Each fluorescence emission spectrum shown in FIG. 4A is normalized so that the peak intensity at the maximum peak is 1.

As shown in FIG. 4A, when the first fluorescent ink 13 was irradiated with UV-A, it emitted blue (first color) light having a peak wavelength λ _1A of about 445 nm and was irradiated with UV-C. At this time, it emits red (second color) light having a peak wavelength λ _1C of about 610 nm. As described above, the first fluorescent ink 13 includes a so-called dichroic phosphor (first phosphor) whose emission color is different between UV-A irradiation and UV-C irradiation. Such a dichroic phosphor is constituted, for example, by appropriately combining a phosphor excited by UV-A and a phosphor excited by UV-C (for example, JP-A-10-251570). No. publication).
During UV-A irradiation, light having a wavelength of about 610 nm is also emitted as shown in FIG. 4A. However, since light having a wavelength of about 610 nm has a lower intensity than light having a peak wavelength λ _1A of about 445 nm, the light from the first fluorescent ink 13 is visually recognized as blue light during UV-A irradiation. Similarly, at the time of UV-C irradiation, light having a wavelength of about 445 nm is also emitted as shown in FIG. 4A, but the light from the first fluorescent ink 13 is visually recognized as red light because of its low intensity.

(Second fluorescent ink)
Next, the second fluorescent ink 14 will be described. In FIG. 4B, the alternate long and short dash line indicates the fluorescence emission spectrum of the second fluorescent ink 14 when irradiated with UV-A, and the solid line indicates the fluorescence of the second fluorescent ink 14 when irradiated with UV-C. The emission spectrum is shown. As in the case of FIG. 4A, each fluorescence emission spectrum shown in FIG. 4B is standardized so that the peak intensity at the maximum peak is 1.

As shown in FIG. 4B, when the second fluorescent ink 14 is irradiated with UV-A, blue (first color) light having a peak wavelength λ _2A of about 445 nm, or the same color as blue (first color) Emits light that is visible. The second fluorescent ink 14 emits green (third color) light having a peak wavelength λ _2C of about 525 nm when irradiated with UV-C. As described above, the second fluorescent ink 14 also includes a so-called dichroic phosphor (second phosphor) that emits different colors when irradiated with UV-A and when irradiated with UV-C, like the first fluorescent ink 13. It is out.
During UV-A irradiation, light having a wavelength of about 525 nm is also emitted as shown in FIG. 4B. However, since light having a wavelength of about 525 nm has a lower intensity than light having a peak wavelength λ _2A of about 445 nm, the light from the second fluorescent ink 14 is visually recognized as blue light during UV-A irradiation. Similarly, at the time of UV-C irradiation, light having a wavelength of about 445 nm is also emitted as shown in FIG. 4B. However, since the intensity is small, the light from the second fluorescent ink 14 is visually recognized as green light.

Next, with reference to FIG. 5, the color of light emitted from the first fluorescent ink 13 or the second fluorescent ink 14 during UV-A or UV-C irradiation will be described in more detail. In the reference numerals shown in FIG. 5, white circles or squares indicate the chromaticities of light emitted from the first fluorescent ink 13 or the second fluorescent ink 14 during UV-A irradiation, respectively. The black circles or squares indicate the chromaticities of light emitted from the first fluorescent ink 13 or the second fluorescent ink 14 during UV-C irradiation, respectively.

The blue color (first color) described above corresponds to the chromaticity indicated by the white circle in FIG. Further, the red color (second color) corresponds to the chromaticity indicated by the black circle in FIG. 5, and the green color (third color) is indicated by the black square in FIG. It corresponds to chromaticity.

As shown in FIG. 5, in the xy chromaticity diagram, the chromaticity of light emitted from the first fluorescent ink 13 during UV-A irradiation, and the chromaticity of light emitted from the second fluorescent ink 14 during UV-A irradiation. Are close. For this reason, as described above, the light emitted from the second fluorescent ink 14 when irradiated with UV-A is visually recognized as the same color as the light emitted from the first fluorescent ink 13 when irradiated with UV-A. For this reason, the pattern area 20 formed using the first fluorescent ink 13 and the background area 25 formed using the second fluorescent ink 14 are visually recognized as the same color area during UV-A irradiation. Therefore, as will be described later, during UV-A irradiation, the entire light-emitting image 12 is visually recognized as a single color (blue) image, and thus the pattern of the pattern region 20 does not appear.

Also, as shown in FIG. 5, in the xy chromaticity diagram, the chromaticity of light emitted from the first fluorescent ink 13 during UV-C irradiation and the chromaticity of light emitted from the second fluorescent ink 14 during UV-C irradiation. Is far away. For this reason, the light emitted from the second fluorescent ink 14 when irradiated with UV-C is visually recognized as light having a different color from the light emitted from the first fluorescent ink 13 when irradiated with UV-C. For this reason, the pattern area 20 formed using the first fluorescent ink 13 and the background area 25 formed using the second fluorescent ink 14 are visually recognized as different color areas during UV-C irradiation. Therefore, as will be described later, the pattern of the pattern area 20 is visually recognized during UV-C irradiation.

In the present invention, “same color” means that the chromaticities of two colors are close to each other to the extent that the color difference cannot be determined with the naked eye. More specifically, “same color” means that the color difference ΔE ^* _ab between the two colors is 10 or less, preferably 3 or less. The “different color” means that the color difference ΔE ^* _ab between the two colors is larger than 10. Here, the color difference ΔE ^* _ab is a value calculated based on L ^* , a ^* and b ^* in the L ^* a ^* b ^* color system, and is an index relating to a color difference when observed with the naked eye. Is the value. ^{Incidentally,} ^L * in the L ^* a * ^{b *} color system, ^{a *} and ^{b *,} or tristimulus values X in the XYZ color system, Y and Z, is calculated based on the spectrum of light. A relationship according to a well-known conversion equation is established between L ^* , a ^*, and b ^* and the tristimulus values X, Y, and Z.
The tristimulus values can be measured by using a measuring instrument such as a spectrophotometer, a color difference meter, a colorimeter, a color meter, a chromaticity meter, for example. Among these measuring instruments, the spectrophotometer can obtain the spectral reflectance of each wavelength, and therefore can measure the tristimulus values with high accuracy, and is therefore suitable for analyzing the color difference.
In order to calculate the color difference ΔE ^* _ab , for example, first, light from a plurality of media (inks) to be compared is measured with a spectrophotometer, and based on the result, tristimulus values X, Y, Z, or L ^* , a ^* , b ^* are calculated. Then, ^L * in a plurality of media ^(ink), a *, ^b difference ^{^{^{* (ΔL *, Δa *,}}} Δb *) from to calculate the color difference on the basis of the following equation.

Next, the operation of the present embodiment having such a configuration will be described. Here, first, a method for producing the forgery prevention medium 10 will be described. Next, a method for inspecting whether the securities comprising the forgery prevention medium 10 are genuine will be described.

First , a base material 11 is prepared. As the base material 11, for example, a base material made of white polyethylene terephthalate having a thickness of 188 μm is used. Next, using the first fluorescent ink 13 and the second fluorescent ink 14, a luminescent image composed of the pattern region 20 and the background region 25 is formed on the base material 11.

At this time, as the first fluorescent ink 13 and the second fluorescent ink 14, for example, 25% by weight of dichroic phosphor having a predetermined fluorescent property, 8% by weight of microsilica, 2% by weight of organic bentonite, and alkyd resin 50 are used. Inks made into offset inks by adding 15% by weight and 15% by weight of an alkylbenzene solvent are used. Among these, as the dichroic phosphor (first phosphor) for the first fluorescent ink 13, for example, it is excited by ultraviolet light having a wavelength of 254 nm to emit red light, and is excited by ultraviolet light having a wavelength of 365 nm to emit blue light. A phosphor DE-RB (manufactured by Nemoto Special Chemical) that emits light is used. As the dichroic phosphor (second phosphor) for the second fluorescent ink 14, for example, it is excited by ultraviolet light having a wavelength of 254 nm to emit green light, and is excited by ultraviolet light having a wavelength of 365 nm to emit blue light. The phosphor DE-GB (manufactured by Nemoto Special Chemical) is used.
The ink is such that the color difference ΔE ^* _ab between the blue light emitted from the first fluorescent ink 13 and the blue light emitted from the second fluorescent ink 14 when irradiated with ultraviolet light having a wavelength of 365 nm is 10 or less, preferably 3 or less. 13, 14 dichroic phosphors are respectively selected. In general, when the color difference ΔE ^* _ab is about 3, it becomes the limit of human eye discrimination ability, that is, ability to distinguish colors. Therefore, by setting the color difference ΔE ^* _ab to 3 or less, it becomes more difficult to discriminate the color with the naked eye, thereby preventing the pattern of the luminescent image 12 for authenticity discrimination from being easily elucidated. it can.

In addition, the composition of each component in the 1st fluorescent ink 13 and the 2nd fluorescent ink 14 is not restricted to the above-mentioned composition, According to the characteristic calculated | required by the forgery prevention medium 10, an optimal composition is set.

Confirmation Method Next, with reference to FIGS. 2, 6A and 6B, a method for confirming whether the securities comprising the forgery prevention medium 10 are genuine will be described.

(At the time of visible light irradiation)
First, the anti-counterfeit medium 10 is observed under visible light. In this case, as described above, the base material 11, the pattern region 20 and the background region 25 of the light-emitting image 12 are visually recognized as white (see FIG. 2). For this reason, the pattern of the pattern area | region 20 of the light emission image 12 does not appear under visible light.

(During UV-A irradiation)
Next, the forgery prevention medium 10 at the time of UV-A irradiation is observed. As UV-A to be irradiated, for example, ultraviolet light having a wavelength of 365 nm is used.

FIG. 6A is a plan view showing a light emission image 12 of the forgery prevention medium 10 at the time of UV-A irradiation. The first fluorescent ink 13 forming the pattern area 20 contains the phosphor DE-RB, and therefore the first fluorescent ink 13 emits blue light. Therefore, the pattern area 20 is visually recognized as the blue portion 21b. On the other hand, the second fluorescent ink 14 forming the background region 25 contains the phosphor DE-GB, and therefore the second fluorescent ink 14 emits blue light. Therefore, the background region 25 is also visually recognized as the blue portion 26b. As described above, the pattern area 20 and the background area 25 are visually recognized as the same color area during the UV-A irradiation. Accordingly, the pattern of the pattern area 20 of the luminescent image 12 does not appear during UV-A irradiation.

(At UV-C irradiation)
Next, the anti-counterfeit medium 10 during UV-C irradiation is observed. As UV-C to be irradiated, for example, ultraviolet light having a wavelength of 254 nm is used.

FIG. 6B is a plan view showing the light emission image 12 of the forgery prevention medium 10 at the time of UV-C irradiation. The first fluorescent ink 13 forming the pattern area 20 contains the phosphor DE-RB, and therefore the first fluorescent ink 13 emits red light. Therefore, the pattern area 20 is visually recognized as the red portion 21c. On the other hand, the second fluorescent ink 14 forming the background region 25 contains the phosphor DE-GB, and therefore the second fluorescent ink 14 emits green light. Therefore, the background region 25 is visually recognized as the green portion 26c. In this way, the pattern area 20 and the background area 25 are visually recognized as different color areas during UV-C irradiation. Therefore, at the time of UV-C irradiation, the pattern of the pattern area 20 of the luminescent image 12 is visually recognized.

By checking that the colors of the pattern area 20 and the background area 25 change as described above when irradiated with visible light, UV-A, or UV-C, the securities composed of the anti-counterfeit medium 10 are authorized. It is confirmed that it is a thing.

As described above, according to the present embodiment, the forgery prevention medium 10 includes the base material 11, the pattern region 20 formed on the base material 11 using the first fluorescent ink 13 including the first phosphor, and the pattern. And a background region 25 formed on the substrate 11 using the second fluorescent ink 14 containing the second phosphor so as to be adjacent to the region 20. Of these, the first phosphor of the first fluorescent ink 13 emits blue (first color) light when irradiated with UV-A, and red (second color) when irradiated with UV-C. It is made of a phosphor DE-RB that emits the above light. On the other hand, when the second phosphor of the second fluorescent ink 14 is irradiated with UV-A, it emits light of a color that is visually recognized as the same color as blue (first color) or blue (first color). The phosphor DE-GB emits green (third color) light when irradiated with -C. Therefore, the pattern area 20 and the background area 25 are visually recognized as areas of the same color when irradiated with UV-A, and are visually recognized as areas of different colors when irradiated with UV-C. Moreover, the pattern area | region 20 and the background area | region 25 are formed so that it may mutually adjoin. For this reason, the pattern area 20 and the background area 25 are not discriminated when irradiated with UV-A, but are discriminated only after being irradiated with UV-C. That is, the pattern of the pattern area 20 is not visually recognized when irradiated with UV-A, but is recognized only when irradiated with UV-C.
Thus, by forming the pattern region 20 and the background region 25 using the ink containing the dichroic phosphor, the forgery of the anti-counterfeit medium 10 is made as compared with the case where the ink containing the monochromatic phosphor is used. Can be difficult. In addition, it is possible to easily and quickly determine whether or not the luminescent image 12 is normal with the naked eye.
Further, by selecting the first phosphor of the first fluorescent ink 13 and the second phosphor of the second fluorescent ink 14 so as to emit the same color or the color that is visually recognized as the same color when irradiated with UV-A, It is possible to prevent the pattern of the luminescent image 12 from being easily solved. Thereby, forgery of the forgery prevention medium 10 can be made more difficult.
In addition, the first fluorescent ink of the first fluorescent ink 13 and the second fluorescent ink 14 and the second fluorescent ink 14 appear so that the pattern of the picture area 20 appears only after irradiation with UV-C, which is difficult to prepare a light source as compared with UV-A. By selecting the second phosphor, it is possible to more firmly prevent the pattern of the pattern area 20 from being clarified. This makes it more difficult to forge the anti-counterfeit medium 10.

Modification In this embodiment, the pattern area 20 and the background area 25 of the luminescent image 12 are formed on the base 11 by using the first fluorescent ink 13 including the first phosphor and the second fluorescent ink 14 including the second phosphor. An example formed by solid printing is shown. However, the present invention is not limited to this. By printing the first fluorescent ink 13 including the first phosphor and the second fluorescent ink 14 including the second phosphor on the substrate 11 in the same predetermined pattern, The region 20 and the background region 25 may be formed. Hereinafter, an example in which the first fluorescent ink 13 and the second fluorescent ink 14 are printed in a stripe shape on the substrate 11 will be described with reference to FIGS. 7 to 9B.

FIG. 7 is a plan view showing a luminescent image 12 of the anti-counterfeit medium 10 under visible light in this modification, and FIG. 8 is a cross-sectional view taken along the line VIII-VIII of the luminescent image 12 shown in FIG. is there. As shown in FIGS. 7 and 8, in this modification, the pattern area 20 and the background area 25 are formed by printing the first fluorescent ink 13 and the second fluorescent ink 14 on the base material 11 in a stripe shape. Has been.

Next, with reference to FIG. 7, FIG. 9A and FIG. 9B, a method for inspecting whether the securities comprising the anti-counterfeit medium 10 are genuine in this modification will be described.

(At the time of visible light irradiation)
Under visible light, as shown in FIG. 7, the pattern area 20 and the background area 25 are each formed of

white portions

21a and 26a arranged in a stripe shape. For this reason, the pattern of the pattern area | region 20 of the light emission image 12 does not appear under visible light.

(During UV-A irradiation)
FIG. 9A is a plan view showing a light emission image 12 of the forgery prevention medium 10 at the time of UV-A irradiation. The pattern area 20 and the background area 25 are each formed of

blue portions

21b and 26b arranged in a stripe shape. For this reason, the pattern of the pattern area 20 of the luminescent image 12 does not appear during UV-A irradiation.
Moreover, in this modification, compared with the case where the 1st fluorescent ink 13 and the 2nd fluorescent ink 14 are solid-printed on the base material 11, the blue part 21b of the pattern area | region 20 and the blue part 26b of the background area | region 25 are different. There are fewer parts to touch. For this reason, even if there is light that is irregularly reflected or refracted at the portion where the blue portion 21b and the blue portion 26b are in contact, the blue portion 21b and the blue portion 26b are caused by such light. The possibility that the boundary between them is visually recognized is reduced. As a result, it is possible to more firmly prevent the pattern of the pattern area 20 from being solved during UV-A irradiation.

(At UV-C irradiation)
FIG. 9B is a plan view showing a light emission image 12 of the forgery prevention medium 10 at the time of UV-C irradiation. The pattern area 20 and the background area 25 are each formed of a red portion 21c and a green portion 26c arranged in a stripe shape. For this reason, the pattern of the pattern area 20 of the light emission image 12 is visually recognized at the time of UV-C irradiation.

In addition, in this modification, the example in which the 1st fluorescent ink 13 and the 2nd fluorescent ink 14 were printed on the base material 11 at stripe form was shown. However, the present invention is not limited to this, and the first fluorescent ink 13 and the second fluorescent ink 14 can be printed on the substrate 11 in various patterns.
For example, the first fluorescent ink 13 and the second fluorescent ink 14 may be printed on the substrate 11 with halftone dots. The halftone dot percentage at this time is not particularly limited, and the halftone dot percentage is appropriately set according to the characteristics required for the forgery prevention medium 10.

Other Modifications In the present embodiment, an example in which an ink containing the phosphor DE-RB is used as the first fluorescent ink 13 and an ink containing the phosphor DE-GB is used as the second fluorescent ink 14 is used. Indicated. That is, an example in which the ink of the combination_1 in Table 1 shown below is used is shown. However, the present invention is not limited to this, and the first fluorescent ink 13 and the second fluorescent ink 14 may be inks of combination_2 or combination_3 in Table 1. Even in the case of the combination_2 or the combination_3, as in the case of the combination_1, the first fluorescent ink 13 and the second fluorescent ink 14 have colors that are visually recognized as the same color or the same color when irradiated with UV-A. It is a luminescent ink. For this reason, it is possible to prevent the pattern of the luminescent image 12 from being easily elucidated, which makes it more difficult to forge the anti-counterfeit medium 10.
In Table 1, the colors shown in the column “UV-A” or “UV-C” are the first fluorescent ink 13 and the second fluorescent ink 14 when UV-A or UV-C is irradiated. The color of the light emitted from each is shown. Further, the names shown in the column of “phosphor” all represent product names in the fundamental special chemistry. In this case, in the product name “DE-X ₁ X ₂ ”, X ₁ indicates a light emission color at the time of UV-C irradiation, and X ₂ indicates a light emission color at the time of UV-A irradiation. For example, the phosphor DE-GR is a phosphor that emits green light when irradiated with UV-C and emits red light when irradiated with UV-A.

In the present embodiment, an example is shown in which the pattern area 20 is formed using the first fluorescent ink 13 and the background area 25 is formed using the second fluorescent ink 14. However, the present invention is not limited to this, and the pattern area 20 may be formed using the second fluorescent ink 14 and the background area 25 may be formed using the first fluorescent ink 13. Also in this case, the pattern of the pattern area 20 is not visually recognized when irradiated with UV-A, but is recognized only when irradiated with UV-C. This makes it difficult to forge the anti-counterfeit medium 10.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. 10 to 11B. The second embodiment shown in FIGS. 10 to 11B is different from the second embodiment in that the second fluorescent ink 14 is composed of an ink that does not emit light when irradiated with UV-C. This is substantially the same as the first embodiment shown in FIGS. 1 to 9B. In the second embodiment shown in FIGS. 10 to 11B, the same parts as those in the first embodiment shown in FIGS. 1 to 9B are denoted by the same reference numerals, and detailed description thereof is omitted.

(Second fluorescent ink)
First, the second fluorescent ink 14 in the present embodiment will be described with reference to FIG. In FIG. 10, the alternate long and short dash line indicates the fluorescence emission spectrum of the second fluorescent ink 14 when irradiated with UV-A, and the solid line indicates the fluorescence of the second fluorescent ink 14 when irradiated with UV-C. The emission spectrum is shown. In FIG. 10, the intensity at the peak of the spectrum (solid line) at the time of UV-C irradiation is shown as a relative intensity when the peak intensity at the maximum peak of the spectrum at the time of UV-A irradiation (dashed line) is 1. Has been.

As shown in FIG. 10, when the second fluorescent ink 14 is irradiated with UV-A, blue (first color) light having a peak wavelength λ _2A of about 445 nm, or the same color as blue (first color) Emits light that is visible. Further, when the second fluorescent ink 14 is irradiated with UV-C, it emits light having a wavelength of about 445 nm, which has a remarkably smaller intensity than the peak intensity at the time of UV-A irradiation. As described above, the light emitted from the second fluorescent ink 14 at the time of UV-C irradiation has a very small intensity, and is hardly detected by the naked eye. For this reason, the second fluorescent ink 14 is visually recognized as a colorless ink during UV-C irradiation. Thus, in the present embodiment, the second phosphor included in the second fluorescent ink 14 is a monochromatic phosphor that emits light only when UV-A is irradiated.

In the present invention, “colorless” means that the color visually recognized when observing the second fluorescent ink 14 is determined by elements other than the color of light emitted from the second fluorescent ink 14 itself. . For example, when the second fluorescent ink 14 is irradiated with only UV-C irradiation, the second fluorescent ink 14 is visually recognized as black. Further, when the second fluorescent ink 14 is irradiated with UV-C and visible light, the visible light is scattered by the pigment particles in the second fluorescent ink 14 as described above. Visible as white.

Further, in the present invention, “does not emit light when irradiated with UV-C” means not only when no light is emitted when irradiated with UV-C, but also by the naked eye as shown by a solid line in FIG. Is a concept that includes the case of emitting light of a small intensity that cannot be detected as light of a specific color.

Since the first fluorescent ink 13 used at this time is the same as the first fluorescent ink 13 in the first embodiment shown in FIGS. 1 to 9B, detailed description thereof is omitted. As the second fluorescent ink 14, by adding 25% by weight of a monochromatic phosphor having a predetermined fluorescence characteristic, 8% by weight of microsilica, 2% by weight of organic bentonite, 50% by weight of alkyd resin, and 15% by weight of an alkylbenzene solvent are added. An offset ink is used. As the monochromatic phosphor (second phosphor) for the second fluorescent ink 14, for example, a phosphor D-1184 (manufactured by Nemoto Special Chemical) that emits blue light with ultraviolet light having a wavelength of 365 nm is used.

Confirmation Method Next, with reference to FIGS. 11A and 11B, a method for confirming whether the securities comprising the anti-counterfeit medium 10 are genuine will be described.

(During UV-A irradiation)
FIG. 11A is a plan view showing a light emission image 12 of the forgery prevention medium 10 at the time of UV-A irradiation. The first fluorescent ink 13 forming the pattern area 20 contains the phosphor DE-RB, and therefore the first fluorescent ink 13 emits blue light. Therefore, the pattern area 20 is visually recognized as the blue portion 21b. On the other hand, the second fluorescent ink 14 forming the background region 25 includes the phosphor D-1184, and therefore the second fluorescent ink 14 emits blue light. Therefore, the background region 25 is also visually recognized as the blue portion 26b. As described above, the pattern area 20 and the background area 25 are visually recognized as the same color area during the UV-A irradiation. Accordingly, the pattern of the pattern area 20 of the luminescent image 12 does not appear during UV-A irradiation.

(At UV-C irradiation)
FIG. 11B is a plan view showing the light emission image 12 of the forgery prevention medium 10 at the time of UV-C irradiation. The first fluorescent ink 13 forming the pattern area 20 contains the phosphor DE-RB, and therefore the first fluorescent ink 13 emits red light. Therefore, the pattern area 20 is visually recognized as the red portion 21c. On the other hand, the second fluorescent ink 14 forming the background region 25 is made of an ink that does not emit light when irradiated with UV-C. Therefore, the background region 25 is visually recognized as a colorless portion 26d. Therefore, at the time of UV-C irradiation, the pattern of the pattern area 20 of the luminescent image 12 is visually recognized.

As described above, according to the present embodiment, the forgery prevention medium 10 includes the base material 11, the pattern region 20 formed on the base material 11 using the first fluorescent ink 13 including the first phosphor, and the pattern. And a background region 25 formed on the substrate 11 using the second fluorescent ink 14 containing the second phosphor so as to be adjacent to the region 20. Of these, the first phosphor of the first fluorescent ink 13 emits blue (first color) light when irradiated with UV-A, and red (second color) when irradiated with UV-C. It is made of a phosphor DE-RB that emits the above light. On the other hand, when the second phosphor of the second fluorescent ink 14 is irradiated with UV-A, it emits light of a color that is visually recognized as the same color as blue (first color) or blue (first color). The phosphor D-1184 does not emit light when irradiated with -C. Therefore, the pattern area 20 and the background area 25 are visually recognized as areas of the same color when irradiated with UV-A, and are visually recognized as areas of different colors when irradiated with UV-C. Moreover, the pattern area | region 20 and the background area | region 25 are formed so that it may mutually adjoin. For this reason, the pattern area 20 and the background area 25 are not discriminated when irradiated with UV-A, but are discriminated only after being irradiated with UV-C. That is, the pattern of the pattern area 20 is not visually recognized when irradiated with UV-A, but is recognized only when irradiated with UV-C.
Thus, forgery of the anti-counterfeit medium 10 can be made difficult by forming the pattern region 20 using ink containing a dichroic phosphor that emits a different color depending on the wavelength of the irradiated light. . In addition, it is possible to easily and quickly determine whether or not the luminescent image 12 is normal with the naked eye.
Further, by selecting the first phosphor of the first fluorescent ink 13 and the second phosphor of the second fluorescent ink 14 so as to emit the same color or the color that is visually recognized as the same color when irradiated with UV-A, It is possible to prevent the pattern of the luminescent image 12 from being easily solved. Thereby, forgery of the forgery prevention medium 10 can be made more difficult.
In addition, the first fluorescent ink of the first fluorescent ink 13 and the second fluorescent ink 14 and the second fluorescent ink 14 appear so that the pattern of the picture area 20 appears only after irradiation with UV-C, which is difficult to prepare a light source as compared with UV-A. By selecting the second phosphor, it is possible to more firmly prevent the pattern of the pattern area 20 from being clarified. This makes it more difficult to forge the anti-counterfeit medium 10.

In this embodiment, an example in which an ink containing phosphor DE-RB is used as the first fluorescent ink 13 and an ink containing phosphor D-1184 is used as the second fluorescent ink 14 is shown. . That is, an example in which the ink of combination_1 in Table 2 shown below is used is shown. However, the present invention is not limited to this, and as the first fluorescent ink 13 and the second fluorescent ink 14, the inks of combinations_2 to 6 in Table 2 may be used. Even in the case of the combination_2 to the combination_6, as in the case of the combination_1, the first fluorescent ink 13 and the second fluorescent ink 14 have colors that are visually recognized as the same color or the same color when irradiated with UV-A. It is a luminescent ink. For this reason, it is possible to prevent the pattern of the luminescent image 12 from being easily elucidated, which makes it more difficult to forge the anti-counterfeit medium 10.
In Table 2, “colorless” in the column “UV-C” indicates that no light is emitted. In Table 2, the names shown in the column “phosphor” all represent product names in the fundamental special chemistry.

In the present embodiment, an example is shown in which the pattern area 20 is formed using the first fluorescent ink 13 and the background area 25 is formed using the second fluorescent ink 14. However, the present invention is not limited to this, and the pattern area 20 may be formed using the second fluorescent ink 14 and the background area 25 may be formed using the first fluorescent ink 13. Also in this case, the pattern of the luminescent image 12 constituted by the pattern region 20 and the background region 25 is not visually recognized when irradiated with UV-A, but is recognized only when irradiated with UV-C. This makes it difficult to forge the anti-counterfeit medium 10.

Further, in the present embodiment, the first fluorescent ink 13 and the second fluorescent ink 14 are placed on the base material 11 in the same predetermined pattern as in the modification of the first embodiment shown in FIGS. 7 to 9B. The pattern area 20 and the background area 25 may be formed by printing on.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. 12A to 14B. In the third embodiment shown in FIGS. 12A to 14B, the first fluorescent ink and the second fluorescent ink are selected so as to emit light of the same color or the color that is visually recognized as the same color when irradiated with UV-C. The other configuration is substantially the same as that of the first embodiment shown in FIGS. 1 to 9B. In the third embodiment shown in FIGS. 12A to 14B, the same parts as those in the first embodiment shown in FIGS. 1 to 9B are denoted by the same reference numerals, and detailed description thereof is omitted.

Fluorescent ink First, with reference to FIG. 12A thru | or FIG. 13, the 1st fluorescent ink 13 and the 2nd fluorescent ink 14 in this Embodiment are demonstrated in detail. FIG. 12A is a diagram showing a fluorescence emission spectrum of the first fluorescent ink 13, and FIG. 12B is a diagram showing a fluorescence emission spectrum of the second fluorescence ink 14. FIG. 13 is an xy chromaticity diagram showing the chromaticity of light emitted from the first fluorescent ink 13 and the second fluorescent ink 14 in the XYZ color system when light in a specific wavelength region is irradiated.

(First fluorescent ink)
First, the first fluorescent ink 13 will be described. In FIG. 12A, the alternate long and short dash line indicates the fluorescence emission spectrum of the first fluorescent ink 13 when irradiated with UV-A (invisible light in the second wavelength region), and the solid line indicates UV-C (first The fluorescence emission spectrum of the first fluorescent ink 13 when irradiated with invisible light in the wavelength region is shown. Each fluorescence emission spectrum shown in FIG. 12A is standardized so that the peak intensity at the maximum peak is 1.

As shown in FIG. 12A, when the first fluorescent ink 13 was irradiated with UV-C, it emitted green (first color) light having a peak wavelength λ _1C of about 525 nm and was irradiated with UV-A. At this time, blue (second color) light having a peak wavelength λ _1A of about 445 nm is emitted.
During UV-C irradiation, light having a wavelength of about 445 nm is also emitted as shown in FIG. 12A. However, since light having a wavelength of about 445 nm has a lower intensity than light having a peak wavelength λ _1C of about 525 nm, the light from the first fluorescent ink 13 is visually recognized as green light during UV-C irradiation. Similarly, at the time of UV-A irradiation, light having a wavelength of about 525 nm is also emitted as shown in FIG. 12A, but the light from the first fluorescent ink 13 is visually recognized as blue light because of its low intensity.

(Second fluorescent ink)
Next, the second fluorescent ink 14 will be described. In FIG. 12B, the alternate long and short dash line indicates the fluorescence emission spectrum of the second fluorescent ink 14 when irradiated with UV-A, and the solid line indicates the fluorescence of the second fluorescent ink 14 when irradiated with UV-C. The emission spectrum is shown. Similarly to the case of FIG. 12A, each fluorescence emission spectrum shown in FIG. 12B is standardized so that the peak intensity at the maximum peak is 1.

As shown in FIG. 12B, when the second fluorescent ink 14 is irradiated with UV-C, green (first color) light having a peak wavelength λ _2C of about 525 nm or the same color as green (first color) Emits light that is visible. The second fluorescent ink 14 emits red (third color) light having a peak wavelength λ _2A of about 610 nm when irradiated with UV-A.
During UV-C irradiation, light having a wavelength of about 610 nm is also emitted as shown in FIG. 12B. However, since light having a wavelength of about 610 nm has a lower intensity than light having a peak wavelength λ _2C of about 525 nm, the light from the second fluorescent ink 14 is visually recognized as green light during UV-C irradiation.

Next, with reference to FIG. 13, the color of light emitted from the first fluorescent ink 13 or the second fluorescent ink 14 during UV-A or UV-C irradiation will be described in more detail. In the reference numerals shown in FIG. 13, white squares or triangles indicate the chromaticities of light emitted from the first fluorescent ink 13 or the second fluorescent ink 14 during UV-A irradiation, respectively. Black squares or triangles indicate the chromaticity of light emitted from the first fluorescent ink 13 or the second fluorescent ink 14 during UV-C irradiation, respectively.

The green color (first color) described above corresponds to the chromaticity indicated by the black square in FIG. Further, the blue color (second color) described above corresponds to the chromaticity indicated by a white square in FIG. 13, and the red color (third color) is indicated by a white triangle in FIG. It corresponds to chromaticity.

As shown in FIG. 13, in the xy chromaticity diagram, the chromaticity of light emitted from the first fluorescent ink 13 during UV-C irradiation, and the chromaticity of light emitted from the second fluorescent ink 14 during UV-C irradiation. Are close. Therefore, as described above, the light emitted from the second fluorescent ink 14 when irradiated with UV-C is visually recognized as the same color as the light emitted from the first fluorescent ink 13 when irradiated with UV-C. For this reason, the pattern area 20 formed using the first fluorescent ink 13 and the background area 25 formed using the second fluorescent ink 14 are visually recognized as the same color area during UV-C irradiation. Therefore, as will be described later, during UV-C irradiation, the entire light-emitting image 12 is visually recognized as a single color (green) image, and thus the pattern of the pattern region 20 does not appear.

Further, as shown in FIG. 13, in the xy chromaticity diagram, the chromaticity of light emitted from the first fluorescent ink 13 during UV-A irradiation and the chromaticity of light emitted from the second fluorescent ink 14 during UV-C irradiation. Is far away. For this reason, the light emitted from the second fluorescent ink 14 when irradiated with UV-A is visually recognized as light having a different color from the light emitted from the first fluorescent ink 13 when irradiated with UV-A. For this reason, the pattern region 20 formed using the first fluorescent ink 13 and the background region 25 formed using the second fluorescent ink 14 are visually recognized as different color regions during UV-A irradiation. Accordingly, as will be described later, the pattern of the pattern area 20 is visually recognized during UV-A irradiation.

At this time, as the first fluorescent ink 13 and the second fluorescent ink 14, for example, 25% by weight of dichroic phosphor having a predetermined fluorescent property, 8% by weight of microsilica, 2% by weight of organic bentonite, and alkyd resin 50 are used. Inks made into offset inks by adding 15% by weight and 15% by weight of an alkylbenzene solvent are used. Among these, as the dichroic phosphor (first phosphor) for the first fluorescent ink 13, for example, it is excited by ultraviolet light having a wavelength of 254 nm to emit green light, and is excited by ultraviolet light having a wavelength of 365 nm to emit blue light. A phosphor DE-GB (manufactured by Nemoto Special Chemical) that emits light is used. The dichroic phosphor (second phosphor) for the second fluorescent ink 14 is, for example, excited by ultraviolet light having a wavelength of 254 nm to emit green light, and excited by ultraviolet light having a wavelength of 365 nm to emit red light. The phosphor DE-GR (manufactured by Nemoto Special Chemical) is used. The ink is such that the color difference ΔE ^* _ab between the green light emitted from the first fluorescent ink 13 and the green light emitted from the second fluorescent ink 14 when irradiated with ultraviolet light having a wavelength of 254 nm is 10 or less, preferably 3 or less. 13, 14 dichroic phosphors are respectively selected.

Confirmation Method Next, with reference to FIGS. 14A and 14B, a method for confirming whether or not the securities comprising the forgery prevention medium 10 are genuine will be described.

(At UV-C irradiation)
FIG. 14A is a plan view showing a light emission image 12 of the forgery prevention medium 10 at the time of UV-C irradiation. The first fluorescent ink 13 forming the pattern region 20 contains the phosphor DE-GB, and therefore the first fluorescent ink 13 emits green light. Therefore, the pattern area 20 is visually recognized as the green portion 22c. On the other hand, the second fluorescent ink 14 forming the background region 25 contains the phosphor DE-GR, and therefore the second fluorescent ink 14 emits green light. Therefore, the background region 25 is also visually recognized as the green portion 27c. Thus, the pattern area 20 and the background area 25 are visually recognized as areas of the same color during UV-C irradiation. Therefore, the pattern of the pattern area 20 of the luminescent image 12 does not appear during UV-C irradiation.

(During UV-A irradiation)
FIG. 14B is a plan view showing a light emission image 12 of the forgery prevention medium 10 at the time of UV-A irradiation. The first fluorescent ink 13 forming the pattern area 20 contains the phosphor DE-GB, and therefore the first fluorescent ink 13 emits blue light. Therefore, the pattern area 20 is visually recognized as the blue portion 22b. On the other hand, the second fluorescent ink 14 forming the background region 25 contains the phosphor DE-GR, and therefore the second fluorescent ink 14 emits red light. Therefore, the background region 25 is visually recognized as a red portion 27b. As described above, the pattern area 20 and the background area 25 are visually recognized as different color areas during UV-A irradiation. Therefore, the pattern of the pattern area 20 of the luminescent image 12 is visually recognized during UV-A irradiation.

As described above, according to the present embodiment, the forgery prevention medium 10 includes the base material 11, the pattern region 20 formed on the base material 11 using the first fluorescent ink 13 including the first phosphor, and the pattern. And a background region 25 formed on the substrate 11 using the second fluorescent ink 14 containing the second phosphor so as to be adjacent to the region 20. The first phosphor of the first fluorescent ink 13 emits green (first color) light when irradiated with UV-C, and blue (second color) when irradiated with UV-A. It is made of a phosphor DE-GB that emits the above-mentioned light. On the other hand, when the second phosphor of the second fluorescent ink 14 is irradiated with UV-C, the second phosphor emits light of a color visually recognized as green (first color) or the same color as green (first color). The phosphor DE-GR emits red (third color) light when irradiated with -A. For this reason, the pattern area 20 and the background area 25 are visually recognized as areas of the same color when irradiated with UV-C, and are visually recognized as areas of different colors when irradiated with UV-A. Moreover, the pattern area | region 20 and the background area | region 25 are formed so that it may mutually adjoin. For this reason, the pattern area 20 and the background area 25 are not discriminated when irradiated with UV-C, but are discriminated only after being irradiated with UV-A. That is, the pattern in the pattern area 20 is not visually recognized when irradiated with UV-C, but is recognized only when irradiated with UV-A.
Thus, by forming the pattern region 20 and the background region 25 using the ink containing the dichroic phosphor, the forgery of the anti-counterfeit medium 10 is made as compared with the case where the ink containing the monochromatic phosphor is used. Can be difficult. In addition, it is possible to easily and quickly determine whether or not the luminescent image 12 is normal with the naked eye.
In addition, by selecting the first phosphor of the first fluorescent ink 13 and the second phosphor of the second fluorescent ink 14 so as to emit light of the same color or a color visually recognized as the same color when irradiated with UV-C, It is possible to prevent the pattern of the luminescent image 12 from being easily solved. Thereby, forgery of the forgery prevention medium 10 can be made more difficult.

In this embodiment, an example in which an ink containing phosphor DE-GB is used as the first fluorescent ink 13 and an ink containing phosphor DE-GR is used as the second fluorescent ink 14 is shown. . That is, an example in which the ink of combination_1 in Table 3 shown below is used is shown. However, the present invention is not limited to this, and as the first fluorescent ink 13 and the second fluorescent ink 14, the ink of the combination_2 or the combination_3 in Table 3 may be used. Even in the case of the combination_2 or the combination_3, as in the case of the combination_1, the first fluorescent ink 13 and the second fluorescent ink 14 have colors that are visually recognized as the same color or the same color when irradiated with UV-A. It is a luminescent ink. For this reason, it is possible to prevent the pattern of the luminescent image 12 from being easily elucidated, which makes it more difficult to forge the anti-counterfeit medium 10.
In Table 3, the names shown in the column of “phosphor” all represent product names in fundamental special chemistry.

Other Modifications In the present embodiment, an example is shown in which the second fluorescent ink 14 is composed of a dichroic phosphor. However, the present invention is not limited to this, and the second fluorescent ink 14 may be made of a monochromatic phosphor as in the case of the second embodiment shown in FIGS. 10 to 11B. In this case, the combination of the first fluorescent ink 13 and the second fluorescent ink 14 is not particularly limited, and various combinations can be appropriately selected as shown in Table 4 below.
In Table 4, the names shown in the column of “phosphor” all represent product names in fundamental special chemistry.

In the present embodiment, an example is shown in which the pattern area 20 is formed using the first fluorescent ink 13 and the background area 25 is formed using the second fluorescent ink 14. However, the present invention is not limited to this, and the pattern area 20 may be formed using the second fluorescent ink 14 and the background area 25 may be formed using the first fluorescent ink 13. Also in this case, the pattern of the luminescent image 12 constituted by the pattern region 20 and the background region 25 is not visually recognized when irradiated with UV-C, but is recognized only when irradiated with UV-A. This makes it difficult to forge the anti-counterfeit medium 10.

Further, in each of the above embodiments, an example in which ink having excitation characteristics for UV-A or UV-C is used as the first fluorescent ink 13 and the second fluorescent ink 14 has been shown. However, the present invention is not limited to this, and the first fluorescent ink 13 and the second fluorescent ink 14 may be ink having excitation characteristics with respect to UV-B or infrared rays. That is, invisible light in an arbitrary wavelength region can be used as “invisible light in the first wavelength region” or “invisible light in the second wavelength region” in the present invention.

Further, in each of the above embodiments, an example is shown in which the background region 25 is formed so as to surround the pattern region 20. However, the present invention is not limited to this, and it is only necessary that at least a part of the background area 25 is adjacent to the pattern area 20.

Further, in each of the above embodiments, an example is shown in which the pattern area 20 and the background area 25 are visually recognized as white under visible light. However, the present invention is not limited to this, and it is sufficient that the pattern area 20 and the background area 25 are visually recognized as areas of the same color at least under visible light.

Further, in each of the above embodiments, an example is shown in which the color of light emitted from the first fluorescent ink 13 and the second fluorescent ink 14 is any one of blue, red, and green. However, the present invention is not limited to this, and various combinations of various colors that are visually recognized as the same color when irradiated with invisible light within the first wavelength region and are visually recognized as different colors when irradiated with invisible light within the second wavelength region. Ink can be used as

inks

13,14.

In each of the above-described embodiments, the example in which the light-emitting medium of the present invention is used as an anti-counterfeit medium constituting securities or the like has been shown. However, the present invention is not limited to this, and the light emitting medium of the present invention can be used in various applications. For example, the light-emitting medium of the present invention can also be used in applications such as toys. Also in this case, it is not discriminated when irradiated with invisible light in the first wavelength region, and it is determined only after irradiation with invisible light in the second wavelength region. Various functions and qualities can be added.

In each of the above embodiments, when invisible light in the second wavelength region is irradiated, the first phosphor emits light of the second color, and the second phosphor emits light of the third color. In addition, an example is shown in which light is not emitted, and thus the first region including the first phosphor and the second region including the second phosphor are visually recognized as differently colored regions. However, the present invention is not limited to this.
That is, when invisible light in the first wavelength region is irradiated, the first phosphor and the second phosphor emit light having a color that is visually recognized as the same color, and invisible light in the second wavelength region. As long as the first region including the first phosphor and the second region including the second phosphor are visually recognized as different color regions, the emission color of the first phosphor is arbitrarily set. It is possible.
For example, when invisible light in the first wavelength region is irradiated, the first color light is emitted, and when invisible light in the second wavelength region is irradiated, the first color or the first color is also emitted. The 1st fluorescent substance which light-emits the light of the color visually recognized as the same color may be used. In this case, when invisible light in the first wavelength region is irradiated, the first phosphor emits light of the first color, and the second phosphor is visually recognized as the same color as the first color or the first color. Emit light of a certain color. For this reason, the first region and the second region are visually recognized as regions of the same color. On the other hand, when invisible light in the second wavelength region is irradiated, the first phosphor emits light of a color that is visually recognized as the first color or the same color as the first color, and the second phosphor Emits light of three colors or emits no light. For this reason, the first region and the second region are visually recognized as regions of different colors. Therefore, the pattern of the luminescent image composed of the first region and the second region is not visible when irradiated with invisible light in the first wavelength region, but only after being irradiated with invisible light in the second wavelength region. Visible. As a result, it is possible to easily and quickly confirm the emission image.

Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIGS. 15 to 17B.

In the first to third embodiments described above, an example in which at least a part of the first region of the luminescent image 12 is adjacent to the second region of the luminescent image 12 has been described. More specifically, the first region of the luminescent image 12 is composed of the pattern region 20, and the second region of the luminescent image 12 is composed of the background region 25 at least part of which is adjacent to the pattern region 20. An example was given. However, the form of the first region and the second region is not limited to the above-described form. As long as the 1st field is formed from the 1st fluorescent ink 13 containing the 1st fluorescent substance and the 2nd field is formed from the 2nd fluorescent ink 14 containing the 2nd fluorescent substance, the 1st field of various forms And a second region can be considered.

Hereinafter, in the present embodiment, referring to FIG. 15 to FIG. 17B, the first region of the luminescent image 12 has at least one first pattern region including the first phosphor, An example will be described in which the two regions have at least one second pattern region including the second phosphor, and the first pattern region and the second pattern region are arranged independently of each other. In the fourth embodiment shown in FIGS. 15 to 17B, the same parts as those in the first embodiment shown in FIGS. 1 to 9B are denoted by the same reference numerals, and detailed description thereof is omitted.

Emission Image FIG. 15 is a plan view showing the emission image 12 under visible light, and FIG. 16 is a cross-sectional view along the line XVI-XVI of the emission image 12 shown in FIG. First, with reference to FIG. 15, the pattern of the luminescent image 12 in the present embodiment will be described.

As shown in FIG. 15, the luminescent image 12 includes a plurality of floral first pattern areas (first areas) 30, a plurality of floral second pattern areas (second areas) 35, and a blank area 50. have. In the example shown in FIG. 15, each first pattern region 30 includes a flower heart part 30a and a plurality of petal parts 30b arranged around the flower heart part 30a. Similarly, each second pattern region 35 includes a flower heart part 35a and a plurality of petal parts 35b arranged around the flower heart part 35a. Thus, the shape of each first pattern region 30 is substantially the same as the shape of each second pattern region 35. Note that “substantially the same” here refers to the first pattern region 30 and the second pattern region 35 when the first pattern region 30 and the second pattern region 35 are visually recognized as regions of the same color as described later. This means that the shape of the first pattern region 30 and the shape of the second pattern region 35 are similar to the extent that can be recognized as regions of the same type.

Each first pattern region 30 and each second pattern region 35 are arranged independently of each other. For example, as shown in FIG. 15, one first pattern region 30 is arranged apart from the other first pattern regions 30 and second pattern regions 35. Similarly, the one second pattern region 35 is disposed apart from the other second pattern region 35 and the first pattern region 30.

In addition, in the example shown in FIG. 15, each 1st pattern area | region 30 and each 2nd pattern area | region 35 showed the example mutually spaced apart and arrange | positioned. However, the present invention is not limited to this, and each first pattern region 30 and each second pattern region 35 may be partially adjacent to each other as long as each can be recognized as a separate pattern region. Alternatively, they may partially overlap each other. That is, “arranged independently of each other” means that the first pattern areas 30 and the second pattern areas 35 are arranged so as to be recognized as separate pattern areas.

Next, the structure of the luminescent image 12 will be described with reference to FIG. As shown in FIG. 16, the first pattern region 30 and the second pattern region 35 of the luminescent image 12 are formed by printing the first fluorescent ink 13 and the second fluorescent ink 14 on the substrate 11. Since the thickness of the 1st fluorescent ink 13 and the thickness of the 2nd fluorescent ink 14 are substantially the same as the case of the above-mentioned 1st Embodiment, detailed description is abbreviate | omitted. As the base material 11, white polyethylene terephthalate is used as in the case of the first embodiment.

As in the case of the first embodiment described above, each of the first fluorescent ink 13 and the second fluorescent ink 14 is a predetermined phosphor that does not emit light under visible light but emits light under specific invisible light, for example, Contains granular pigments. Here, the particle size of the pigment contained in the

inks

13 and 14, the light is scattered by the pigment particles. Therefore, when the luminescent image 12 is viewed under visible light, as shown in FIG. 15, the white portion 31 a is visually recognized as the first pattern region 30 and the white portion 36 a is visually recognized as the second pattern region 35. Further, as described above, the base material 11 is formed of white polyethylene terephthalate. For this reason, the blank area | region 50 is visually recognized as the white part 51a under visible light. Therefore, under visible light, the first pattern region 30, the second pattern region 35, and the blank region 50 of the luminescent image 12 are all visually recognized as white. Therefore, the patterns of the

pattern areas

30 and 35 of the luminescent image 12 do not appear under visible light. This prevents the forgery prevention medium 10 having the luminescent image 12 from being easily forged.

Fluorescent ink Next, the first fluorescent ink 13 and the second fluorescent ink 14 will be described.

(First fluorescent ink)
The first fluorescent ink 13 emits blue (first color) light having a peak wavelength λ _1A of about 445 nm when irradiated with UV-A, and the peak wavelength λ _1C is irradiated with UV-C. It emits red (second color) light that is about 610 nm. As described above, the first fluorescent ink 13 includes a so-called dichroic phosphor (first phosphor) whose emission color is different between UV-A irradiation and UV-C irradiation. Since the first fluorescent ink 13 and the first phosphor are substantially the same as those in the first embodiment described above, detailed description thereof is omitted.

(Second fluorescent ink)
When the second fluorescent ink 14 is irradiated with UV-A, it emits blue (first color) light having a peak wavelength λ _2A of about 445 nm, or light that is visually recognized as the same color as blue (first color). . The second fluorescent ink 14 emits green (third color) light having a peak wavelength λ _2C of about 525 nm when irradiated with UV-C. As described above, the second fluorescent ink 14 includes a so-called dichroic phosphor (second phosphor) that emits different colors when irradiated with UV-A and when irradiated with UV-C. Since the second fluorescent ink 14 and the second phosphor are substantially the same as those in the first embodiment described above, detailed description thereof is omitted.

First , a base material 11 is prepared. As the base material 11, for example, a base material made of white polyethylene terephthalate having a thickness of 188 μm is used. Next, the luminescent image 12 having the first pattern region 30 and the second pattern region 35 is formed on the substrate 11 by printing using the first fluorescent ink 13 and the second fluorescent ink 14.

At this time, each first pattern region 30 and each second pattern region 35 are arranged so as to be independent from each other. For this reason, compared with the case where the 1st pattern area | region 30 and the 2nd pattern area | region 35 are arrange | positioned so that it may adjoin necessarily, the precision calculated | required by printing is low. Thus, the light emitting image 12 having the first pattern region 30 and the second pattern region 35 can be formed on the substrate 11 by using a simpler printing method or printing machine.

Examples of the first fluorescent ink 13 and the second fluorescent ink 14 include, for example, 25% by weight of a dichroic phosphor having predetermined fluorescence characteristics, 8% by weight of microsilica, 2% by weight of organic bentonite, 50% by weight of alkyd resin, and Inks made into offset inks by adding 15% by weight of an alkylbenzene solvent are used. Among these, as the dichroic phosphor (first phosphor) for the first fluorescent ink 13, for example, it is excited by ultraviolet light having a wavelength of 254 nm to emit red light, and is excited by ultraviolet light having a wavelength of 365 nm to emit blue light. A phosphor DE-RB (manufactured by Nemoto Special Chemical) that emits light is used. As the dichroic phosphor (second phosphor) for the second fluorescent ink 14, for example, it is excited by ultraviolet light having a wavelength of 254 nm to emit green light, and is excited by ultraviolet light having a wavelength of 365 nm to emit blue light. The phosphor DE-GB (manufactured by Nemoto Special Chemical) is used. The ink is such that the color difference ΔE ^* _ab between the blue light emitted from the first fluorescent ink 13 and the blue light emitted from the second fluorescent ink 14 when irradiated with ultraviolet light having a wavelength of 365 nm is 10 or less, preferably 3 or less. 13, 14 dichroic phosphors are respectively selected.

Confirmation Method Next, with reference to FIGS. 17A and 17B, a method for confirming whether the securities comprising the anti-counterfeit medium 10 are genuine will be described.

(At the time of visible light irradiation)
First, the anti-counterfeit medium 10 is observed under visible light. In this case, as described above, the first pattern region 30, the second pattern region 35, and the blank region 50 of the luminescent image 12 are visually recognized as white (see FIG. 15). For this reason, the pattern of each pattern area |

region

30 and 35 does not appear under visible light.

FIG. 17A is a plan view showing a light emission image 12 of the forgery prevention medium 10 at the time of UV-A irradiation. The first fluorescent ink 13 forming each first pattern region 30 contains the phosphor DE-RB, and therefore the first fluorescent ink 13 emits blue light. Accordingly, each first pattern region 30 is visually recognized as a blue portion 31b. On the other hand, the second fluorescent ink 14 forming each second pattern area 35 contains the phosphor DE-GB, and therefore the second fluorescent ink 14 emits blue light. Accordingly, each second pattern region 35 is also visually recognized as a blue portion 36b. Thus, at the time of UV-A irradiation, each first pattern region 30 and each second pattern region 35 are visually recognized as regions of the same color.

In addition, as for the color of the blank area 50 at the time of UV-A irradiation, the following cases can be considered. For example, when visible light is irradiated simultaneously with UV-A, the blank area 50 is visually recognized as a white portion 51a as shown in FIG. 17A. On the other hand, when only the UV-A is irradiated on the light-emitting image 12 under the condition where the visible light is shielded, the blank area 50 is visually recognized as a colorless portion (not shown).

FIG. 17B is a plan view showing the light emission image 12 of the forgery prevention medium 10 at the time of UV-C irradiation. The first fluorescent ink 13 that forms each first pattern region 30 contains the phosphor DE-RB, and therefore the first fluorescent ink 13 emits red light. Therefore, each 1st pattern area | region 30 is visually recognized as the red part 31c. On the other hand, the second fluorescent ink 14 forming each second pattern region 35 contains the phosphor DE-GB, and therefore the second fluorescent ink 14 emits green light. Accordingly, each second pattern region 35 is visually recognized as a green portion 36c. Thus, at the time of UV-C irradiation, each first pattern region 30 and each second pattern region 35 are visually recognized as regions of different colors.

Note that the following cases can be considered for the color of the blank area 50 during UV-C irradiation. For example, when visible light is also irradiated onto the luminescent image 12 simultaneously with UV-C, as shown in FIG. 17B, the blank area 50 is visually recognized as a white portion 51a. On the other hand, when only the UV-C is irradiated on the luminescent image 12 under the condition where the visible light is shielded, the blank area 50 is visually recognized as a colorless portion (not shown).

By checking that the colors of the first pattern areas 30 and the second pattern areas 35 change as described above when irradiated with visible light, UV-A, or UV-C, the anti-counterfeit medium 10 Is confirmed to be genuine.

As described above, according to the present embodiment, the forgery prevention medium 10 includes the base 11 and the first pattern region 30 formed on the base 11 using the first fluorescent ink 13 including the first phosphor. And a second pattern region 35 formed on the substrate 11 using the second fluorescent ink 14 containing the second phosphor. The first pattern area 30 and the second pattern area 35 are arranged independently of each other. The first phosphor of the first fluorescent ink 13 emits blue (first color) light when irradiated with UV-A, and red (second color) when irradiated with UV-C. It is made of a phosphor DE-RB that emits the above light. On the other hand, when the second phosphor of the second fluorescent ink 14 is irradiated with UV-A, it emits light of a color that is visually recognized as the same color as blue (first color) or blue (first color). The phosphor DE-GB emits green (third color) light when irradiated with -C. Therefore, the first pattern region 30 and the second pattern region 35 are visually recognized as regions of the same color when irradiated with UV-A, and are visually recognized as regions of different colors when irradiated with UV-C.
Thus, by forming the 1st pattern area | region 30 and the 2nd pattern area | region 35 using the ink containing a dichroic fluorescent substance, compared with the case where the ink containing a monochromatic fluorescent substance is used, a forgery prevention medium Ten counterfeiting can be made difficult. In addition, it is possible to easily and quickly determine whether or not the luminescent image 12 is normal with the naked eye.

Further, by selecting the first phosphor of the first fluorescent ink 13 and the second phosphor of the second fluorescent ink 14 so as to emit the same color or the color that is visually recognized as the same color when irradiated with UV-A, It is possible to prevent the structure of the luminescent image 12 from being easily solved. That is, it is possible to prevent the light emission image 12 from being easily elucidated that the plurality of types of

pattern regions

30 and 35 are included. Thereby, forgery of the forgery prevention medium 10 can be made more difficult. This effect is further enhanced by making the shape of each first pattern region 30 and the shape of each second pattern region 35 substantially the same.

In addition, it is possible to visually recognize that the light-emitting image 12 includes a plurality of types of

pattern regions

30 and 35 only when UV-C, which makes it difficult to prepare a light source as compared with UV-A, is irradiated. By selecting the first phosphor and the second phosphor of the first fluorescent ink 13 and the second fluorescent ink 14, it is possible to more firmly prevent the structure of the luminescent image 12 from being elucidated. This makes it more difficult to forge the anti-counterfeit medium 10.

Further, by forming the plurality of

pattern areas

30 and 35 in the luminescent image 12 and making the phosphors included in the

pattern areas

30 and 35 different, variations in the design of the luminescent image 12 can be increased. Thereby, the designability of the luminescent image 12 can be improved.

In this embodiment, an ink containing phosphor DE-RB is used as first fluorescent ink 13, and an ink containing phosphor DE-GB is used as second fluorescent ink 14. Indicated. That is, the example in which the ink of the combination _1 in Table 1 described in the first embodiment is used is shown. However, the present invention is not limited to this, and as the first fluorescent ink 13 and the second fluorescent ink 14, as in the case of the first embodiment described above, the inks of combination_2 or combination_3 in Table 1 are used. Also good.

In the modification and the present embodiment regarding the shape of the pattern region, each first pattern region 30 formed from the first fluorescent ink 13 has a floral pattern and each formed from the second fluorescent ink 14 The example in which all the 2nd pattern area | regions 35 have the shape of a floral pattern was shown. However, the shape of the first pattern region 30 and the second pattern region 35 included in the light emitting image 12 is not limited to one type. For example, as shown in FIG. 18, the first pattern region 30 and the second pattern region 35 may include not only a flower pattern shape but also a star shape.

In the example shown in FIG. 18, the star-shaped first pattern region 30 is formed of the first fluorescent ink 13 containing the first phosphor, similarly to the floral first pattern region 30. Similarly, the star-shaped second pattern region 35 is formed from the second fluorescent ink 14 containing the second phosphor, similarly to the floral second pattern region 35. For this reason, the first pattern region 30 and the second pattern region 35 are visually recognized as regions of the same color when irradiated with UV-A, and are visually recognized as regions of different colors when irradiated with UV-C.

According to the example shown in FIG. 18, the configuration of the luminescent image 12 can be made more complicated by increasing variations in the shape of each first pattern region 30 and each second pattern region 35. This makes it more difficult to forge the anti-counterfeit medium 10. Moreover, the design property of the light emission image 12 can be improved.

Fifth Embodiment Next, a fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment shown in FIG. 19 is different only in that the second fluorescent ink 14 is composed of ink that does not emit light when irradiated with UV-C. This is substantially the same as the fourth embodiment shown in FIG. In the fifth embodiment shown in FIG. 19, the same parts as those in the fourth embodiment shown in FIGS. 15 to 18 are denoted by the same reference numerals, and detailed description thereof is omitted.

(First fluorescent ink)
The first fluorescent ink 13 emits blue (first color) light having a peak wavelength λ _1A of about 445 nm when irradiated with UV-A, and the peak wavelength λ _1C is irradiated with UV-C. It emits red (second color) light that is about 610 nm. Since the first fluorescent ink 13 and the first phosphor are substantially the same as those in the first and fourth embodiments described above, detailed description thereof is omitted.

(Second fluorescent ink)
In the present embodiment, the second phosphor contained in the second fluorescent ink 14 is monochromatic that emits light that is visually recognized as the same color as blue (first color) or blue (first color) only during UV-A irradiation. It is a phosphor. That is, during UV-C irradiation, the second fluorescent ink 14 is visually recognized as colorless ink. Since the second fluorescent ink 14 and the second phosphor are substantially the same as those in the second embodiment described above, detailed description thereof is omitted.

First , a base material 11 is prepared. As the base material 11, for example, a base material made of white polyethylene terephthalate having a thickness of 188 μm is used. Next, the luminescent image 12 having the first pattern region 30 and the second pattern region 35 is formed on the substrate 11 by printing using the first fluorescent ink 13 and the second fluorescent ink 14. Since the arrangement method of each 1st pattern area | region 30 and each 2nd pattern area | region 35 is substantially the same as the case of the above-mentioned 4th Embodiment, detailed description is abbreviate | omitted.

As the dichroic phosphor (first phosphor) for the first fluorescent ink 13, for example, it is excited by ultraviolet rays having a wavelength of 254 nm to emit red light, and is excited by ultraviolet rays having a wavelength of 365 nm to emit blue light. A phosphor DE-RB (manufactured by Nemoto Special Chemical) is used. In addition, as the monochromatic phosphor (second phosphor) for the second fluorescent ink 14, for example, a phosphor D-1184 (manufactured by Nemoto Special Chemical) that emits blue light with ultraviolet light having a wavelength of 365 nm is used.

Confirmation Method Next, with reference to FIG. 19, a method for confirming whether the securities comprising the anti-counterfeit medium 10 are genuine is described.

(During UV-A irradiation)
The first fluorescent ink 13 forming each first pattern region 30 contains the phosphor DE-RB, and therefore the first fluorescent ink 13 emits blue light. Accordingly, as in the case of the above-described fourth embodiment, each first pattern region 30 is visually recognized as a blue portion 31b (see FIG. 17A). On the other hand, the second fluorescent ink 14 forming each second pattern region 35 contains the phosphor D-1184, and therefore the second fluorescent ink 14 emits blue light. Therefore, each second pattern region 35 is visually recognized as a blue portion 36b as in the case of the fourth embodiment described above (see FIG. 17A). Thus, at the time of UV-A irradiation, each first pattern region 30 and each second pattern region 35 are visually recognized as regions of the same color.

(At UV-C irradiation)
FIG. 19 is a plan view showing a light emission image 12 of the forgery prevention medium 10 at the time of UV-C irradiation. The first fluorescent ink 13 that forms each first pattern region 30 contains the phosphor DE-RB, and therefore the first fluorescent ink 13 emits red light. Therefore, each 1st pattern area | region 30 is visually recognized as the red part 31c. On the other hand, the second fluorescent ink 14 that forms each second pattern region 35 is made of an ink that does not emit light during UV-C irradiation. Accordingly, each second pattern region 35 is visually recognized as a colorless portion 36d. Thus, at the time of UV-C irradiation, each first pattern region 30 and each second pattern region 35 are visually recognized as regions of different colors.

As described in the fourth embodiment, it is conceivable that the blank area 50 is visually recognized as a colorless portion (not shown) during UV-C irradiation. In this case, it is also conceivable that each second pattern area 35 and the blank area 50 are not distinguished, and as a result, only the first pattern area 30 including the red portion 31c is visually recognized.

As described above, according to the present embodiment, the forgery prevention medium 10 includes the base 11 and the first pattern region 30 formed on the base 11 using the first fluorescent ink 13 including the first phosphor. And a second pattern region 35 formed on the substrate 11 using the second fluorescent ink 14 containing the second phosphor. The first pattern area 30 and the second pattern area 35 are arranged independently of each other. The first phosphor of the first fluorescent ink 13 emits blue (first color) light when irradiated with UV-A, and red (second color) when irradiated with UV-C. It consists of a phosphor DE-RB that emits light. On the other hand, when the second phosphor of the second fluorescent ink 14 is irradiated with UV-A, it emits light of a color that is visually recognized as the same color as blue (first color) or blue (first color). The phosphor D-1184 does not emit light when irradiated with -C. For this reason, the first pattern region 30 and the second pattern region 35 are visually recognized as regions of the same color when irradiated with UV-A, and are visually recognized as regions of different colors when irradiated with UV-C.
Thus, forgery of the anti-counterfeit medium 10 is made difficult by forming the first pattern region 30 using ink containing a dichroic phosphor that emits a different color depending on the wavelength of the irradiated light. Can do. In addition, it is possible to easily and quickly determine whether or not the luminescent image 12 is normal with the naked eye.

pattern regions

In this embodiment, an example in which an ink containing phosphor DE-RB is used as the first fluorescent ink 13 and an ink containing phosphor D-1184 is used as the second fluorescent ink 14 is shown. . That is, the example in which the ink of the combination _1 in Table 2 described in the second embodiment is used is shown. However, the present invention is not limited to this, and as the first fluorescent ink 13 and the second fluorescent ink 14, the inks of the combinations _2 to _6 in Table 2 are used as in the case of the second embodiment described above. Also good.

Sixth Embodiment Next, a sixth embodiment of the present invention will be described with reference to FIGS. 20A and 20B. In the sixth embodiment shown in FIGS. 20A and 20B, the first fluorescent ink and the second fluorescent ink are selected to emit light of the same color or a color that is visually recognized as the same color when irradiated with UV-C. The other configurations are the same as those of the fourth embodiment shown in FIGS. 15 to 18. In the sixth embodiment shown in FIGS. 20A and 20B, the same parts as those in the fourth embodiment shown in FIGS. 15 to 18 are denoted by the same reference numerals, and detailed description thereof is omitted.

(First fluorescent ink)
The first fluorescent ink 13 emits green (first color) light having a peak wavelength λ _1C of about 525 nm when irradiated with UV-C, and the peak wavelength λ _1A when irradiated with UV-A. Emits blue (second color) light of about 445 nm. Since the first fluorescent ink 13 and the first phosphor are substantially the same as those in the third embodiment described above, detailed description thereof is omitted.

(Second fluorescent ink)
When the second fluorescent ink 14 is irradiated with UV-C, it emits green (first color) light having a peak wavelength λ _2C of about 525 nm, or light that is visually recognized as the same color as green (first color). . The second fluorescent ink 14 emits red (third color) light having a peak wavelength λ _2A of about 610 nm when irradiated with UV-A. Since the second fluorescent ink 14 and the second phosphor are substantially the same as those in the third embodiment described above, detailed description thereof is omitted.

As the dichroic phosphor (first phosphor) for the first fluorescent ink 13, for example, green light is emitted by being excited by ultraviolet light having a wavelength of 254 nm, and blue light is emitted by being excited by ultraviolet light having a wavelength of 365 nm. The phosphor DE-GB (manufactured by Nemoto Special Chemical) is used. The dichroic phosphor (second phosphor) for the second fluorescent ink 14 is, for example, excited by ultraviolet light having a wavelength of 254 nm to emit green light, and excited by ultraviolet light having a wavelength of 365 nm to emit red light. The phosphor DE-GR (manufactured by Nemoto Special Chemical) is used. The ink is such that the color difference ΔE ^* _ab between the green light emitted from the first fluorescent ink 13 and the green light emitted from the second fluorescent ink 14 when irradiated with ultraviolet light having a wavelength of 254 nm is 10 or less, preferably 3 or less. 13, 14 dichroic phosphors are respectively selected.

Confirmation Method Next, with reference to FIGS. 20A and 20B, a method for confirming whether the securities comprising the forgery prevention medium 10 are genuine will be described.

(At UV-C irradiation)
FIG. 20A is a plan view showing a light emission image 12 of the forgery prevention medium 10 at the time of UV-C irradiation. The first fluorescent ink 13 forming each first pattern region 30 contains the phosphor DE-GB, and therefore the first fluorescent ink 13 emits green light. Therefore, each 1st pattern area | region 30 is visually recognized as the green part 32c. On the other hand, the second fluorescent ink 14 forming each second pattern region 35 contains the phosphor DE-GR, and therefore the second fluorescent ink 14 emits green light. Accordingly, each second pattern region 35 is also visually recognized as a green portion 37c. Thus, at the time of UV-C irradiation, each first pattern region 30 and each second pattern region 35 are visually recognized as regions of the same color.

(During UV-A irradiation)
FIG. 20B is a plan view showing a light emission image 12 of the forgery prevention medium 10 at the time of UV-A irradiation. The first fluorescent ink 13 forming each first pattern region 30 contains the phosphor DE-GB, and therefore the first fluorescent ink 13 emits blue light. Therefore, each 1st pattern area | region 30 is visually recognized as the blue part 32b. On the other hand, the second fluorescent ink 14 forming each second pattern region 35 contains the phosphor DE-GR, and therefore the second fluorescent ink 14 emits red light. Accordingly, each second pattern region 35 is visually recognized as a red portion 37b. Thus, at the time of UV-A irradiation, each first pattern region 30 and each second pattern region 35 are visually recognized as different color regions.

As described above, according to the present embodiment, the forgery prevention medium 10 includes the base 11 and the first pattern region 30 formed on the base 11 using the first fluorescent ink 13 including the first phosphor. And a second pattern region 35 formed on the substrate 11 using the second fluorescent ink 14 containing the second phosphor. The first pattern area 30 and the second pattern area 35 are arranged independently of each other. The first phosphor of the first fluorescent ink 13 emits green (first color) light when irradiated with UV-C, and blue (second color) when irradiated with UV-A. It consists of a phosphor DE-GB that emits light. On the other hand, when the second phosphor of the second fluorescent ink 14 is irradiated with UV-C, the second phosphor emits light of a color visually recognized as green (first color) or the same color as green (first color). The phosphor DE-GR emits red (third color) light when irradiated with -A. Therefore, the first pattern region 30 and the second pattern region 35 are visually recognized as regions of the same color when irradiated with UV-C, and are visually recognized as regions of different colors when irradiated with UV-A.
Thus, by forming the 1st pattern area | region 30 and the 2nd pattern area | region 35 using the ink containing a dichroic fluorescent substance, compared with the case where the ink containing a monochromatic fluorescent substance is used, a forgery prevention medium Ten counterfeiting can be made difficult. In addition, it is possible to easily and quickly determine whether or not the luminescent image 12 is normal with the naked eye.

In addition, by selecting the first phosphor of the first fluorescent ink 13 and the second phosphor of the second fluorescent ink 14 so as to emit light of the same color or a color visually recognized as the same color when irradiated with UV-C, It is possible to prevent the structure of the luminescent image 12 from being easily solved. That is, it is possible to prevent the light emission image 12 from being easily elucidated that the plurality of types of

pattern regions

In this embodiment, an example in which an ink containing phosphor DE-GB is used as the first fluorescent ink 13 and an ink containing phosphor DE-GR is used as the second fluorescent ink 14 is shown. . That is, the example in which the ink of the combination _1 in Table 3 described in the third embodiment is used is shown. However, the present invention is not limited to this, and as the first fluorescent ink 13 and the second fluorescent ink 14, as in the case of the third embodiment described above, the inks of combination_2 or combination_3 in Table 3 are used. Also good.

Other Modifications In the present embodiment, an example is shown in which the second fluorescent ink 14 is composed of a dichroic phosphor. That is, the example in which the ink of the combination _1 in Table 4 described in the other modified example of the third embodiment is used is shown. However, the present invention is not limited to this, and the second fluorescent ink 14 may be made of a monochromatic phosphor as in the case of other modifications of the above-described third embodiment. The combination of the first fluorescent ink 13 and the second fluorescent ink 14 in this case is not particularly limited, and as shown in Table 4 described in the other modifications of the third embodiment described above, Various combinations can be appropriately selected.

In the fourth to sixth embodiments, the first fluorescent ink 13 and the second fluorescent ink 14 are made the same predetermined as in the modification of the first embodiment shown in FIGS. 7 to 9B. You may form the 1st pattern area | region 30 and the 2nd pattern area | region 35 by printing on the base material 11 with a pattern.

In the fourth to sixth embodiments, examples in which ink having excitation characteristics for UV-A or UV-C is used as the first fluorescent ink 13 and the second fluorescent ink 14 are shown. However, the present invention is not limited to this, and the first fluorescent ink 13 and the second fluorescent ink 14 may be ink having excitation characteristics with respect to UV-B or infrared rays. That is, invisible light in an arbitrary wavelength region can be used as “invisible light in the first wavelength region” or “invisible light in the second wavelength region” in the present invention.

In the fourth to sixth embodiments, examples in which the first pattern region 30, the second pattern region 35, and the blank region 50 are visually recognized as white under visible light are shown. However, the present invention is not limited to this, and it is sufficient that the first pattern region 30 and the second pattern region 35 are visually recognized as the same color region at least under visible light.

In the fourth to sixth embodiments, examples have been shown in which the color of light emitted from the first fluorescent ink 13 and the second fluorescent ink 14 is any one of blue, red, and green. However, the present invention is not limited to this, and various combinations of various colors that are visually recognized as the same color when irradiated with invisible light within the first wavelength region and are visually recognized as different colors when irradiated with invisible light within the second wavelength region. Ink can be used as

inks

13,14.

In the fourth to sixth embodiments, examples in which the light emitting medium of the present invention is used as an anti-counterfeit medium constituting securities and the like have been shown. However, the present invention is not limited to this, and the light emitting medium of the present invention can be used in various applications. For example, the light-emitting medium of the present invention can also be used in applications such as toys. Also in this case, the first pattern region 30 that is visually recognized as a region of the same color when irradiated with invisible light in the first wavelength region, and that is recognized as a region of different color only after being irradiated with invisible light in the second wavelength region; Various functions and characteristics can be imparted to the toy and the like by the light emitting image 12 having the second pattern region 35.

In the fourth to sixth embodiments, when invisible light in the second wavelength region is irradiated, the first phosphor emits light of the second color, and the second phosphor Therefore, the first pattern region 30 including the first phosphor and the second pattern region 35 including the second phosphor are visually recognized as different color regions. An example was given. However, the present invention is not limited to this.
That is, when invisible light in the first wavelength region is irradiated, the first phosphor and the second phosphor emit light having a color that is visually recognized as the same color, and invisible light in the second wavelength region is emitted. As long as the first pattern region 30 including the first phosphor and the second pattern region 35 including the second phosphor are visually recognized as differently colored regions when irradiated, the emission color of the first phosphor can be arbitrarily set. It is possible to set.
For example, when invisible light in the first wavelength region is irradiated, the first color light is emitted, and when invisible light in the second wavelength region is irradiated, the first color or the first color is also emitted. The 1st fluorescent substance which light-emits the light of the color visually recognized as the same color may be used. In this case, when invisible light in the first wavelength region is irradiated, the first phosphor emits light of the first color, and the second phosphor is visually recognized as the same color as the first color or the first color. Emit light of a certain color. For this reason, the first pattern region 30 and the second pattern region 35 are visually recognized as regions of the same color. On the other hand, when invisible light in the second wavelength region is irradiated, the first phosphor emits light of a color that is visually recognized as the first color or the same color as the first color, and the second phosphor Emits color light or does not emit light. For this reason, the first pattern region 30 and the second pattern region 35 are visually recognized as different color regions. Therefore, it is possible to prevent the structure of the luminescent image 12 from being easily elucidated. That is, it is possible to prevent the light emission image 12 from being easily elucidated that the plurality of types of

pattern regions

30 and 35 are included. This makes it difficult to forge the anti-counterfeit medium 10.

Claims

In a luminescent medium having a luminescent image on a substrate,
The emission image is
A first region containing a first phosphor;
A second region containing a second phosphor,
When invisible light in the first wavelength region is irradiated, the first phosphor and the second phosphor emit light of a color that is visually recognized as the same color,
The light emitting medium, wherein when the invisible light in the second wavelength region is irradiated, the first region and the second region are visually recognized as regions of different colors.
When invisible light in the first wavelength region is irradiated, the first phosphor emits light of the first color, and the second phosphor is visually recognized as the same color as the first color or the first color. Emit light of color,
When invisible light in the second wavelength region is irradiated, the first phosphor emits light of the second color, and the second phosphor emits light of the third color, or emits light. 2. The light emitting medium according to claim 1, wherein the first region and the second region do not emit light and are visually recognized as regions of different colors.
When invisible light in the first wavelength region is irradiated, the first phosphor emits light of the first color, and the second phosphor is visually recognized as the same color as the first color or the first color. Emit light of color,
When invisible light in the second wavelength region is irradiated, the first phosphor emits light of a color that is visually recognized as the first color or the same color as the first color, and the second phosphor has a third color. 2. The light emitting medium according to claim 1, wherein the first region and the second region are visually recognized as regions having different colors from each other.
When the second phosphor is irradiated with invisible light in the first wavelength region, the second phosphor emits light of a color that is visually recognized as the first color or the same color as the first color, and emits invisible light in the second wavelength region. The light emitting medium according to claim 2, which emits light of a third color when irradiated.
When the second phosphor is irradiated with invisible light in the first wavelength region, the second phosphor emits light of a color that is visually recognized as the first color or the same color as the first color, and emits invisible light in the second wavelength region. The light emitting medium according to claim 3, wherein the light emitting medium emits light of a third color when irradiated.
When the second phosphor is irradiated with invisible light in the first wavelength region, the second phosphor emits light of a color that is visually recognized as the first color or the same color as the first color, and emits invisible light in the second wavelength region. The light-emitting medium according to claim 2, wherein the light-emitting medium does not emit light when irradiated.
When the second phosphor is irradiated with invisible light in the first wavelength region, the second phosphor emits light of a color that is visually recognized as the first color or the same color as the first color, and emits invisible light in the second wavelength region. The light-emitting medium according to claim 3, wherein the light-emitting medium does not emit light when irradiated.
When invisible light in the first wavelength region is irradiated, the color difference between the color of light emitted from the first phosphor and the color of light emitted from the second phosphor is 10 or less The luminescent medium according to claim 1, wherein:
When invisible light in the first wavelength region is irradiated, a color difference between the color of light emitted from the first phosphor and the color of light emitted from the second phosphor is 3 or less The luminescent medium according to claim 1, wherein:
2. The luminescent medium according to claim 1, wherein the first region and the second region are respectively formed from the first phosphor and the second phosphor provided in the same predetermined pattern.
The light emitting medium according to claim 1, wherein at least a part of the second region is adjacent to the first region.
The first region has at least one first pattern region including the first phosphor,
The second region has at least one second pattern region including the second phosphor,
The light emitting medium according to claim 1, wherein the first pattern region and the second pattern region are arranged independently of each other.
The luminescent medium according to claim 12, wherein the shape of the first pattern region is substantially the same as the shape of the second pattern region.
In the confirmation method of the luminescent medium having a luminescent image on the substrate,
Preparing a light emitting medium according to claim 1;
Irradiating the light emitting medium with invisible light in the first wavelength region to confirm that the first region and the second region of the luminescent image are not distinguished;
Irradiating the light emitting medium with invisible light in the second wavelength region to confirm that the first region and the second region of the light emission image are discriminated, and confirming the light emitting medium Method.