JP5447242B2 - Anti-counterfeit medium and method for manufacturing the same - Google Patents

Description

  The present invention relates to a technique for preventing forgery of banknotes, securities, certificates, and the like.

  Some banknotes from various countries, when viewed through the light, have a pattern that looks like a finished pattern, with the front and back patterns overlapping. In this method, one design is divided into two, one is printed on the surface of the base material and the other is printed on the back surface of the base material, and there are many simple patterns. Therefore, it can be easily reproduced even with a normal copying machine, and the effect of preventing forgery is low.

  In addition, forgery prevention technology by a printing method or a printing processing method is disclosed in Patent Documents 1 to 4, for example.

JP 2000-272219 A JP 2001-39004 A JP 2007-253600 A JP 2008-12722 A

  The present invention has been made in view of the above circumstances, and it is true / false by confirming an image that appears when a pattern on both sides of a base material is formed by seeing the pattern formed on both sides with light. It is an object of the present invention to provide a forgery-preventing medium that is difficult to forge and a method for manufacturing the same.

  In order to solve the above problems, the present invention provides a counterfeit having a base material, a first pattern provided on one surface of the base material, and a second pattern provided on the other surface of the base material. An anti-counterfeiting pattern, wherein the anti-counterfeiting medium expresses an illusion with the first pattern and the second pattern in a state where the anti-counterfeiting medium is observed through light with one side of the substrate facing forward The second pattern is provided with a calculated decrease in density when the anti-counterfeit medium is watermarked with light on one side of the base material facing forward. A forgery prevention medium is provided.

  In the present invention, the second pattern is provided by calculating a decrease in density when the anti-counterfeit medium is watermarked with light on one side of the substrate in front, When the anti-counterfeit medium is observed through the light in front, the second pattern is visually recognized in a state where the density is lowered. Therefore, in the anti-counterfeit pattern formed by the first pattern and the second pattern, an illusion appears due to light and shade. To do. In a normal copying machine, it is difficult to align the first pattern and the second pattern with high accuracy, and the density decrease when the anti-counterfeit medium is watermarked in the light with one side of the substrate facing forward. It is also difficult to copy the second pattern in consideration of the above. Therefore, in the present invention, a high anti-counterfeit effect can be achieved.

  In the said invention, it is preferable that the said forgery prevention pattern has a high concentration area | region, a medium concentration area | region, and a low concentration area | region. In this case, the high concentration region is configured by the first pattern, the medium concentration region is configured by the second pattern, and the low concentration region is formed on both surfaces of the base material by the first pattern and the second pattern. It is preferable that any part is provided. When the anti-counterfeit medium is watermarked with light on one side of the substrate in front, the second pattern is visually recognized in a state in which the density is lowered. Therefore, both the first pattern and the second pattern are formed on both surfaces of the substrate. This is because an intermediate density region having an intermediate density can be configured with the second pattern with respect to the low density region configured with the portion not provided and the high density region configured with the first pattern. .

  Furthermore, the present invention is a method for producing an anti-counterfeit medium comprising a base material, a first pattern provided on one surface of the base material, and a second pattern provided on the other surface of the base material. The anti-counterfeit medium is a forgery exhibiting an illusion by the first pattern and the second pattern in a state where the one anti-counterfeit medium is facing forward and the anti-counterfeit medium is observed through light. A prevention pattern is formed, a first pattern forming step of forming a first pattern on one surface of the substrate, and the second pattern on the other surface of the substrate. And a second pattern forming step of calculating and forming a decrease in density when the anti-counterfeit medium is watermarked with light on one side in front of the anti-counterfeit medium. .

  In the present invention, the second pattern is formed by calculating the amount of decrease in density when the anti-counterfeit medium is watermarked with light with one side of the substrate facing forward, and as described above, excellent forgery is achieved. The prevention effect can be obtained. Therefore, it is possible to produce an anti-counterfeit medium using existing materials and devices.

  In the present invention, when an anti-counterfeit medium is observed through light, an anti-counterfeit pattern appears and an optical illusion occurs, so that the effect of preventing forgery can be improved.

It is the schematic plan view and sectional drawing which show an example of the forgery prevention medium of this invention. It is a schematic diagram which shows an example of the state which observed the anti-counterfeit medium of the present invention through the light with one side of the substrate facing forward. It is a schematic plan view which shows the other example of the forgery prevention medium of this invention. It is a schematic diagram which shows the other example of the state which observed the anti-counterfeit medium of the present invention through the light with one side of the substrate facing forward. It is a schematic plan view which shows the other example of the forgery prevention medium of this invention. It is a schematic diagram which shows the other example of the state which observed the anti-counterfeit medium of the present invention through the light with one side of the substrate facing forward. It is a schematic plan view which shows the other example of the forgery prevention medium of this invention. It is a schematic diagram which shows the other example of the state which observed the anti-counterfeit medium of the present invention through the light with one side of the substrate facing forward. It is a schematic sectional drawing which shows the other example of the forgery prevention medium of this invention. It is a schematic diagram which shows an example of the illusion figure used for the manufacturing method of the forgery prevention medium of this invention. It is a schematic diagram which shows an example of the pattern which decomposed | disassembled the illusion figure used for the manufacturing method of the forgery prevention medium of this invention.

  Hereinafter, the anti-counterfeit medium of the present invention and the manufacturing method thereof will be described in detail.

A. Anti-counterfeit medium The anti-counterfeit medium of the present invention includes a base material, a first pattern provided on one surface of the base material, and a second pattern provided on the other surface of the base material. An anti-counterfeit pattern, which is a medium and exhibits an optical illusion by the first pattern and the second pattern in a state where the one surface of the substrate is facing forward and the anti-counterfeit medium is observed through light, is observed. The second pattern is formed by calculating a decrease in density when the anti-counterfeit medium is watermarked with light on one side of the substrate facing forward. It is what.

The anti-counterfeit medium of the present invention will be described with reference to the drawings.
1A to 1C are a schematic plan view and a cross-sectional view showing an example of the anti-counterfeit medium of the present invention, and FIG. 1A is a plan view of the anti-counterfeit medium viewed from one side of the substrate. 1B is a plan view of the anti-counterfeit medium viewed from the other side of the substrate, and FIG. 1C is a cross-sectional view taken along the line AA in FIGS. 1A and 1B. As illustrated in FIGS. 1A to 1C, the anti-counterfeit medium 1 includes a base material 2, a first pattern 3 provided on one surface of the base material 2, and the other surface of the base material 2. And a second pattern 4 provided on the surface. The first pattern 3 is a pattern in which squares are regularly arranged, and is printed with a predetermined color and density (for example, black). The second pattern 4 is a lattice pattern having a square opening having the same size as the square of the first pattern 3, and further having a circular opening at the intersection of the lattice, and has a predetermined color and density ( For example, black). The first pattern 3 and the second pattern 4 are printed while being aligned so that the square of the first pattern 3 and the square openings of the grid of the second pattern 4 are aligned.

  FIG. 2 is a schematic diagram showing a state in which the forgery prevention medium 1 shown in FIGS. 1A to 1C is observed through one side of the base material 2 facing through the light. When the anti-counterfeit medium 1 is observed through the light with one side of the substrate 2 facing forward, the anti-counterfeit pattern 10 is formed by the first pattern 3 and the second pattern 4 as illustrated in FIG. . Since the first pattern 3 is printed in a predetermined color and density (for example, black) and has one surface of the substrate 2 facing forward, the first pattern 3 is visually recognized in a state where the density is maintained (for example, black). Since the second pattern 4 is printed in a predetermined color and density (for example, black) and has one surface of the substrate 2 facing forward, the second pattern 4 is visually recognized in a state where the density is reduced (for example, gray). Since light is transmitted through portions where both the first pattern 3 and the second pattern 4 are not printed on both surfaces of the base material 2 (circular portions), they correspond to the color, density, transmittance, etc. of the base material 2 It is visually recognized in a state (for example, white). Therefore, in the forgery prevention pattern 10, the first pattern 3 constitutes a high concentration region 11, the second pattern 4 constitutes a medium concentration region 12, and the first pattern 3 and the second pattern 4 are formed on both surfaces of the substrate 2. The portion where none is printed constitutes the low density region 13.

  Thus, in the state in which the anti-counterfeit medium is observed through the light with one side of the substrate facing forward, the second pattern is visually recognized in a state where the density is lowered. The amount of decrease in density when the anti-counterfeit medium is watermarked with light on one side is calculated and printed. For example, in FIG. 2, when the anti-counterfeit medium 1 is watermarked with light with one side of the base material 2 facing forward, the second pattern 4 is visually recognized in a state of reduced density (for example, gray). As shown in b), the second pattern 4 is printed at a predetermined density (for example, black) based on the decrease in density when the anti-counterfeit medium is watermarked with light on one side of the substrate facing forward. Has been.

  In the present invention, the forgery-preventing pattern expresses an illusion. In the anti-counterfeiting pattern 10 shown in FIG. 2, dark things appear or disappear in the circular low-density region 13 (white) at the intersection of the medium-density region 12 (gray) of the lattice. This is what the black spots that should not actually be appear to flicker, and is called the glittering lattice illusion (Schrauf, Lingelbach and Wist, 1997).

  In the present invention, the “illusion” means an illusion caused by shading, which means that the figure looks different from the actual figure due to the shading.

  When the anti-counterfeit medium 1 shown in FIGS. 1A to 1C is viewed from one surface of the base material 2 by reflected light, the anti-counterfeit medium is viewed from one surface of the base material by transmitted light. As compared with the second pattern, the second pattern is further reduced in density and is difficult to be visually recognized. Since the predetermined density does not appear, no illusion occurs, and the anti-counterfeit pattern cannot be recognized. In addition, when the anti-counterfeit medium 1 shown in FIGS. 1A to 1C is viewed from the other surface of the base material 2 by reflected light, the first pattern has a reduced density and is difficult to be visually recognized. Because there is no shading, no illusion occurs and the anti-counterfeit pattern cannot be recognized. On the other hand, when the anti-counterfeit medium 1 shown in FIGS. 1A to 1C is viewed from one surface of the base material 2 with transmitted light, as illustrated in FIG. Appears, and the illusion is caused by shading.

  As described above, in the present invention, an anti-counterfeit pattern that cannot be normally recognized when viewed through light appears and an illusion occurs, which is effective as an anti-counterfeit technology. In a normal copying machine, it is difficult to align the first pattern and the second pattern with high accuracy, and the density decrease when the anti-counterfeit medium is watermarked in the light with one side of the substrate facing forward. Therefore, it is difficult to reproduce the first pattern and the second pattern so that the anti-counterfeit pattern appears and the illusion appears. Therefore, in the present invention, an excellent anti-counterfeit effect can be obtained.

  Hereinafter, each structure in the forgery prevention medium of this invention is demonstrated.

1. Anti-counterfeiting pattern, first pattern, second pattern The anti-counterfeiting pattern in the present invention is formed on one side of the base material in a state where the anti-counterfeit medium is observed through light with one side of the base side facing forward. It is formed by the provided first pattern and the second pattern provided on the other surface of the base material, and expresses an illusion.

  The anti-counterfeit pattern expresses an illusion due to shading, and is formed by the first pattern and the second pattern in a state where one side of the substrate is facing forward and the anti-counterfeit medium is observed through light. It will not specifically limit if it can obtain. Any illusion figure that expresses an illusion by shading can be used as a forgery prevention pattern.

  For example, as described above, the first pattern 3 printed with a predetermined color and density (for example, black) on one surface of the substrate 2 shown in FIG. 1A and the substrate shown in FIG. The anti-counterfeiting pattern 10 shown in FIG. 2 is formed by the second pattern 4 printed with a predetermined color and density (for example, black) on the other surface of 2. In this anti-counterfeit pattern 10, as described above, dark things appear or disappear in the circular low density region 13 (white) at the intersection of the medium density region 12 (gray) of the lattice. This is what the black dots that should not actually appear to flicker, and is called the twinkle illusion (Schrauf, Lingelbach and Wist (1997)).

3 (a) and 3 (b) are schematic plan views showing other examples of the anti-counterfeit medium of the present invention, and FIG. 3 (a) is a plan view of the anti-counterfeit medium viewed from one surface of the substrate, FIG. 3B is a plan view of the anti-counterfeit medium viewed from the other side of the substrate. FIG. 4 is a schematic diagram showing a state in which the forgery prevention medium shown in FIGS. 3A and 3B is observed through one side of the base material facing through the light.
A first pattern 3 printed in a predetermined color and density (for example, black) on one surface of the substrate 2 shown in FIG. 3A, and a predetermined pattern on the other surface of the substrate 2 shown in FIG. The anti-counterfeit pattern 10 shown in FIG. 4 is formed by the second pattern 4 printed with the color and density (for example, black). Since the second pattern 4 is visually recognized in a state in which the density is lowered, the anti-counterfeiting pattern 10 has a high density region 11 (for example, black) configured by the first pattern 3 and a medium density configured by the second pattern 4. It has the area | region 12 (for example, gray) and the low concentration area | region 11 (for example, white) comprised by the part in which neither the 1st pattern 3 nor the 2nd pattern 4 is printed on both surfaces of the base material 2. FIG. In the forgery prevention pattern 10, the medium density region 12 (gray) line appears to be tilted to the left or right. This is actually a horizontal and parallel line that appears to tilt to the left or right, and is called the Cafewall illusion (Fraser (1908), Gregory and Heard (1979)).

5 (a) and 5 (b) are schematic plan views showing other examples of the forgery prevention medium of the present invention, and FIG. 5 (a) is a plan view of the anti-counterfeit medium viewed from one surface of the substrate, FIG. 5B is a plan view of the anti-counterfeit medium viewed from the other side of the substrate. FIG. 6 is a schematic diagram showing a state in which the anti-counterfeit medium shown in FIGS. 5A and 5B is observed through the light with one side of the substrate facing forward.
The first pattern 3 printed in a predetermined color and density (for example, light gray and dark gray) on one surface of the substrate 2 shown in FIG. 5A and the other of the substrate 2 shown in FIG. 5B The anti-counterfeit pattern 10 shown in FIG. 6 is formed by the second pattern 4 printed with a predetermined color and density (for example, black) on the surface. The first pattern 3 includes a dark gray square 3a and a light gray line 3b. Since the 2nd pattern 4 is visually recognized in the state where the density | concentration fell, the square 3a of the 1st pattern 3 and the 2nd pattern 4 are visually recognized by the density | concentration comparable. Therefore, the anti-counterfeit pattern 10 includes a high concentration region 11 (for example, dark gray) composed of the square 3a of the first pattern 3 and the second pattern 4, and a medium concentration region composed of the line 3b of the first pattern 3. 12 (for example, light gray) and a low-density region 11 (for example, white) composed of portions on which neither the first pattern 3 nor the second pattern 4 is printed on both surfaces of the substrate 2. In the anti-counterfeit pattern 10, the line of the medium density region 12 (light gray) appears to tilt to the left or right. Again, in reality, all horizontal and parallel lines appear to tilt left or right.

  5A, 5B, and 6, the density of the square 3a and the line 3b of the first pattern 3 is different, but the density may be the same. That is, in the forgery prevention pattern, the first pattern square, the first pattern line, and the second pattern square may all be visually recognized at the same density (for example, black). In this case as well, the line (black) appears to tilt left or right.

7 (a) and 7 (b) are schematic plan views showing another example of the forgery prevention medium of the present invention, and FIG. 7 (a) is a plan view of the anti-counterfeit medium viewed from one surface of the substrate, FIG. 7B is a plan view of the anti-counterfeit medium viewed from the other side of the substrate. FIG. 8 is a schematic view showing a state in which the forgery prevention medium shown in FIGS. 7A and 7B is observed through one side of the base material in front of light.
The first pattern 3 printed with a predetermined color and density on one surface of the base material 2 shown in FIG. 7A, and the predetermined color and density on the other surface of the base material 2 shown in FIG. The anti-counterfeiting pattern 10 shown in FIG. The first pattern 3 has gradations in which the density continuously changes, the upper three rows of semicircles become lighter from left to right on the paper surface, and the lower three rows of semicircles on the paper from left to right. The concentration is increasing toward. The second pattern 4 also has a gradation in which the density changes continuously, the density of the upper three rows of semicircles decreases from the left to the right of the page, and the lower three rows of circles indicate the left of the page. Concentration increases from to the right. In this case, since the second pattern 4 is visually recognized in a state in which the density is lowered, the first pattern 3 and the second pattern 3 are continuously changed so that the density continuously changes at the boundary portion between the first pattern 3 and the second pattern 4. The gradation of the pattern 4 is adjusted. As a result, the anti-counterfeit pattern 10 also has a gradation whose density changes continuously. In the forgery prevention pattern 10, the density of the upper three rows of ellipses decreases from left to right on the paper surface, and the density of the lower three rows of ellipses increases from left to right on the paper surface. In the forgery prevention pattern 10, the upper three rows appear to move slowly to the left and the lower three rows appear to move slowly to the right. This is an illusion that appears to move from a low-contrast region to a high-contrast region, and is called the central drift illusion (Kitaoka Akika (2003)).

  In the present invention, the forgery prevention pattern preferably has a high concentration region, a medium concentration region, and a low concentration region. When the anti-counterfeit medium is watermarked with light on one side of the substrate in front, the second pattern is visually recognized in a state where the density is lowered. Because the intermediate density region which is an intermediate density can be configured with the second pattern with respect to the low density region configured with the portion not provided and the high density region configured with the first pattern. is there. Further, contrast affects the expression of the illusion, and high-concentration regions and low-concentration regions can form high-contrast regions, and medium-concentration regions and low-concentration regions can form low-contrast regions.

When the anti-counterfeit pattern has a high concentration region, a medium concentration region, and a low concentration region, the low concentration region is usually configured by a portion where neither the first pattern nor the second pattern is provided on both surfaces of the substrate. The For example, the high concentration region may be configured by the first pattern as illustrated in FIGS. 2 and 4, and may be configured by a part of the first pattern and the second pattern as illustrated in FIG. 6. Although not shown, the second pattern may be used. Further, for example, the intermediate density region may be configured by the second pattern as shown in FIGS. 2 and 4, or may be configured by a part of the first pattern as shown in FIG. Although it does not, you may be comprised by the 1st pattern.
Among them, the high concentration region is composed of the first pattern, the medium concentration region is composed of the second pattern, and the low concentration region is composed of portions where neither the first pattern nor the second pattern is provided on both surfaces of the substrate. It is preferable that As described above, when the anti-counterfeit medium is watermarked with light on one side of the substrate in front, the second pattern is visually recognized in a state where the density is lowered. An intermediate density region having an intermediate density is configured by the second pattern with respect to the low density area configured by a portion where none of the second patterns is provided and the high density region configured by the first pattern. Because it is easy.

  The shapes of the first pattern and the second pattern are appropriately selected according to the shape of the target anti-counterfeit pattern, and the target anti-counterfeit pattern is expressed only by the first pattern or the second pattern. There is no particular limitation as long as it does not cause the optical illusion. Usually, the shapes of the first pattern and the second pattern do not have portions that overlap each other, but have shapes that are adjacent to each other. For example, in FIGS. 1A and 1B, the first pattern 3 is a pattern in which squares are regularly arranged, and the second pattern 4 has a square opening having the same size as the square of the first pattern 3. It is a pattern having a circular opening at a crossing portion of the lattice. As illustrated in FIGS. 1A to 1C, in the first pattern 3 and the second pattern 4, the square of the first pattern 3 and the square opening of the lattice of the second pattern 4 are aligned. So that they are aligned. The shapes of the first pattern 3 and the first pattern 4 are such that the first pattern 3 and the second pattern 4 do not overlap, and the square of the first pattern 3 and the lattice of the second pattern 4 are adjacent to each other. ing. Similarly, in FIGS. 3A, 3B, 5A, 5B, 7A, and 7B, the shapes of the first pattern 3 and the second pattern 4 are the first. The pattern 3 and the second pattern 4 do not overlap with each other, and the first pattern 3 and the second pattern 4 are adjacent to each other. Printing techniques that require such alignment are not easily reproducible even with a normal copying machine, and have a high anti-counterfeit effect.

  The colors of the first pattern and the second pattern are appropriately selected according to the target color of the forgery prevention pattern, and are not particularly limited.

The density | concentration of the 1st pattern provided in the one surface of a base material is suitably adjusted based on the density | concentration of the target forgery prevention pattern.
On the other hand, since the second pattern is visually recognized in a state where the density is lowered when the forgery prevention medium is watermarked with light with one surface of the substrate facing forward, the second pattern is provided on the other surface of the substrate. The density of the two patterns is appropriately adjusted based on the density of the target anti-counterfeit pattern and the decrease in density when the anti-counterfeit medium is watermarked with light on one side of the substrate. In other words, the second pattern is provided by calculating a decrease in density when the forgery prevention medium is watermarked with light on one side of the substrate. The amount of decrease in density varies depending on the transmittance of the substrate.

2. Substrate In the substrate of the present invention, the first pattern is provided on one surface and the second pattern is provided on the other surface.

In the present invention, since the anti-counterfeit medium is observed through the light with one side of the substrate facing forward, the substrate needs to transmit light. On the other hand, if the light transmittance of the base material is high, the anti-counterfeit pattern may be visually recognized without causing the anti-counterfeit medium to pass through the light, and an illusion may occur. Therefore, the printing opacity of the substrate is preferably in the range of 25% to 95%.
Here, the printing opacity refers to an extent that an image printed on a base material cannot be seen through from the opposite side. The printing opacity is affected by the ink permeability in addition to the blank paper opacity (also simply referred to as opacity) of the substrate. Even if the opacity of the substrate is high, if the ink permeability is good, the printing opacity is reduced by the amount of ink penetration.
Further, the blank paper opacity refers to a level where an image of a lower substrate cannot be seen through a single substrate.
The printing opacity of the substrate can be measured with an opacity meter, a hunter whiteness meter, or the like.

Moreover, it is preferable that a base material is hard to penetrate through. This is because if the second pattern breaks through, the anti-counterfeit pattern may be visually recognized without causing the anti-counterfeit medium to pass through the light, and an illusion may occur.
Here, the back-through means that the ink escapes to the opposite surface. The strike-through is not due to the optical properties of the substrate, but due to the penetrability of the ink.
In addition, it can be evaluated that the base material is difficult to see through, for example, by measuring the density of the second pattern when viewed with reflected light with one surface of the base material facing forward. .

  The substrate is not particularly limited as long as it satisfies the above-described characteristics. For example, paper, a resin substrate, or the like can be used. Further, the base material may be one in which a base layer satisfying the above-described characteristics is formed on a transparent resin base material. The material for the underlayer is not particularly limited as long as it satisfies the above-mentioned characteristics, but among them, a material having adhesion to a transparent resin base material is preferable, for example, containing titanium oxide. White coating agent, pigment ink, dye ink, coating material capable of absorbing ink used for printing the first pattern and the second pattern, a coating material for forming a porous layer, and the like.

  When selecting the base material, as described above, when the anti-counterfeit pattern has a high density area, a medium density area, and a low density area, the low density area is usually the first pattern and the first pattern on both sides of the base material. Since the two patterns are composed of portions where none of them is provided, it is preferable to select a base material according to the low concentration region of the target anti-counterfeit pattern.

3. Protective layer In this invention, the protective layer 5 which protects the 1st pattern 3 may be formed so that the 1st pattern 3 may be covered on one surface of the base material 2, as illustrated in FIG. Moreover, the protective layer 6 which protects the 2nd pattern 4 may be formed so that the other surface of the base material 2 may cover the 2nd pattern 4 so that it may illustrate in FIG.
The material of the protective layer is not particularly limited as long as it has transparency and can protect the first pattern and the second pattern, and a general resin material can be used.

4). Applications The anti-counterfeit medium of the present invention can be used for various securities such as banknotes, gift certificates, stock certificates, checks, bills, various certificates such as passports and cards, confidential documents, and the like.

B. Method for Producing Anti-Counterfeit Medium The method for producing an anti-counterfeit medium of the present invention includes a base material, a first pattern provided on one surface of the base material, and a second pattern provided on the other surface of the base material. The anti-counterfeit medium has a pattern, wherein the anti-counterfeit medium has the first pattern in a state where the anti-counterfeit medium is observed through light with one side of the base material facing forward. And the second pattern form an anti-counterfeit pattern that develops an illusion, and forms a first pattern on one surface of the substrate, and the other surface of the substrate. A second pattern forming step of forming the second pattern by calculating a decrease in density when the anti-counterfeit medium is watermarked with light on one side of the substrate. It is a feature.

The manufacturing method of the forgery prevention medium of this invention is demonstrated referring drawings. Here, as an example, an illusion figure 20 illustrated in FIG. 10 appears as an anti-counterfeit pattern when the anti-counterfeit medium is watermarked with light on one side of the substrate.
The illusion figure 20 illustrated in FIG. 10 has three regions, a high concentration region 21 (for example, black), a medium concentration region 22 (for example, gray), and a low concentration region 23 (for example, white). First, as shown in FIGS. 11A and 11B, the illusion figure 20 shown in FIG. 10 is converted into a first element 20a (FIG. 11A) composed of a high concentration region 21, a medium concentration region 22 and a low concentration region. The second element 20b (FIG. 11B) composed of the density region 23 is decomposed into two parts. Next, it is determined which of the first element 20a and the second element 20b is to be printed on the other side of the substrate. Since the second pattern is visually recognized in a state where the density is lowered when the anti-counterfeit medium is watermarked with light on one side of the base material, the second pattern is composed of the medium density area 22 and the low density area 23 here. The second element 20b is printed on the other surface of the substrate, and the first element 20a composed of the high concentration region 21 is printed on one surface of the substrate.

Next, the densities of the first pattern and the second pattern that are actually printed on the substrate are calculated.
The density of the first pattern printed on one side of the substrate is the density of the first pattern when the forgery prevention medium is watermarked with light with one side of the substrate facing forward, and the high density region of the illusion figure. The density is adjusted to be approximately the same. For example, in FIG. 10 and FIG. 11A, when the high density region 21 of the illusion figure is black, the first pattern when the anti-counterfeit medium is watermarked with light facing one side of the base is also black. Thus, the 1st pattern printed on one side of a substrate is made black.
On the other hand, the density of the second pattern printed on the other surface of the base material is the same as the density of the second pattern when the anti-counterfeit medium is watermarked with light on one side of the base material in front, The density is adjusted so that the density in the density area is approximately the same. At this time, since the density of the second pattern decreases when one side of the base material is facing forward and the anti-counterfeit medium is watermarked with light, the density of the second pattern is one side of the base material facing forward. The amount of decrease in density when the anti-counterfeit medium is watermarked with light is calculated and set. For example, in FIG. 10 and FIG. 11B, when the middle density region 22 of the illusion figure is gray, the second pattern when the anti-counterfeit medium is watermarked with light facing one side of the base is also gray. Thus, the 2nd pattern printed on the other side of a substrate is made black.

  Next, the first element 20a shown in FIG. 11A is printed as the first pattern 3 with a density (for example, black) calculated in advance on one surface of the substrate 2 as shown in FIG. 1 pattern formation process). Subsequently, the second element 20b shown in FIG. 11 (b) is printed as the second pattern 4 on the other surface of the substrate 2 with a pre-calculated density (for example, black) as shown in FIG. 1 (b) ( Second pattern forming step). At this time, the first pattern 3 and the second pattern 4 are printed so that their positions are aligned with each other.

FIG. 2 is a schematic diagram showing a state in which the forgery prevention medium 1 shown in FIGS. 1A and 1B is observed through one side of the base material 2 facing through the light. 1A and 1B, as described above, the second pattern 4 calculates the amount of decrease in density when the anti-counterfeit medium is watermarked with light on one side of the substrate in front. Since it is printed, as shown in FIG. 2, the density of the second pattern 4 (medium density region 12) when the forgery prevention medium is watermarked with light facing one side of the substrate is shown in FIG. This is approximately the same as the density of the middle density region 22 of the illusion figure 20. Also, as shown in FIG. 2, the density of the first pattern 3 (high density region 11) when the forgery prevention medium is watermarked with light facing one side of the base is the front of the illusion figure 20 shown in FIG. It becomes the same level as the density of the high density region 21. Furthermore, as shown in FIG. 2, when the forgery prevention medium is watermarked with light on one side of the substrate in front, the first pattern and the second pattern are not printed on both sides of the substrate (low The density of the density area 13) is approximately the same as the density of the low density area 23 of the illusion figure 20 shown in FIG.
Therefore, in a state where one side of the substrate is facing forward and the anti-counterfeit medium is watermarked with light, the original illusion figure is reproduced, an anti-counterfeit pattern appears, and an illusion appears.

  In the present invention, when forming the first pattern and the second pattern, high accuracy is required for the alignment printing technique, but it is possible to produce a forgery prevention medium using existing materials and apparatuses. Is possible.

The anti-counterfeit pattern has been described in detail in the above section “A. Anti-counterfeit medium”, and will not be described here.
Hereinafter, each process in the manufacturing method of the forgery prevention medium of this invention is demonstrated.

1. First pattern forming step The first pattern forming step in the present invention is a step of forming the first pattern on one surface of the substrate.

  The method for forming the first pattern is not particularly limited as long as the first pattern and the second pattern can be formed by alignment. For example, offset printing, gravure printing, letterpress printing, intaglio printing, screen Examples thereof include printing methods such as printing, powder electrophotographic digital printing, liquid electrophotographic digital printing, inkjet digital printing, and transfer methods.

  When forming the first pattern, the density of the first pattern is determined based on the density of the first pattern when the anti-counterfeit medium is watermarked with light on one side of the substrate and the target illusion figure (forgery). It is preferable to adjust so that the density of the high density region of the (prevention pattern) is comparable. The concentration may be obtained by actual measurement or may be obtained by simulation.

  Since the first pattern is described in the above section “A. Anti-counterfeit medium”, description thereof is omitted here.

2. Second Pattern Forming Step The second pattern forming step in the present invention is the concentration of the second pattern on the other side of the base material when the anti-counterfeit medium is watermarked with light on one side of the base side. This is a step of calculating and forming a decrease.

The density of the second pattern is determined by calculating in advance the decrease in density when the anti-counterfeit medium is watermarked with light facing one side of the substrate. The decrease in concentration may be obtained by actual measurement, may be obtained using a calibration curve, or may be obtained by simulation.
When using a calibration curve, for example, the decrease in concentration can be determined as follows. That is, first, a plurality of solid measurement patterns are formed at different concentrations (at least three) on the other surface of the substrate, and then the relative concentration of each measurement pattern by reflection from the other surface of the substrate. (A) is measured, and further, the relative concentration (B) of each measurement pattern by transmission is measured from one side of the base material, and then a calibration curve is obtained from the above relative concentration (A) and relative concentration (B). Create Based on this calibration curve, the second pattern can be formed by predicting the decrease in density when the anti-counterfeit medium is watermarked with light on one side of the substrate. When the same substrate and the same ink are used, it is possible to predict the decrease in density using the prepared calibration curve and form the second pattern.

The method for forming the second pattern is the same as the method for forming the first pattern, and a description thereof is omitted here.
The second pattern is described in the section “A. Anti-counterfeit medium”, and thus the description thereof is omitted here.

3. Other Steps In the present invention, an image processing step for decomposing a target illusion figure into two patterns according to the density may be performed before the first pattern forming step and the second pattern forming step.
The image processing step can be performed using image processing software on a computer system, for example.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

Hereinafter, the present invention will be specifically described with reference to examples.
[Example 1] (paper medium glitter lattice illusion)
(Image processing)
On the CAD system, as shown in FIG. 10, five black squares (high-concentration regions 21) each having a side length of 20 mm are arranged vertically and horizontally with a gap of 4 mm, and a gap portion having a width of 4 mm. Was made gray (medium density region 22), and a white circular shape (low density region 23) having a diameter of 4 mm was arranged at the intersection of the gaps to create a glittering lattice illusion image (illusion figure 20).
As shown in FIGS. 11 (a) and 11 (b), this glittering lattice illusion image (illusion figure 20) is divided into a square portion (first element 20a comprising a high concentration region 21) and other portions (medium concentration region 22). And a second element 20b) consisting of a low density region 23.

(printing)
^Two images obtained by dividing the glittering lattice illusion image were printed on both surfaces of high-quality paper having a thickness of 64 g / m ² by using black ink with an offset printer. On one surface of the fine paper, a square portion was printed at a relative density D = 1.50 (FIG. 1 (a)). On the other surface of the fine paper, a gap portion having a circular opening with a diameter of 4 mm was printed at a relative density D = 1.50 at a portion where the gap with a width of 4 mm intersected (FIG. 1B). . Here, the relative density is a density when the density of a circular part having a diameter of 4 mm is D = 0. At this time, the printing position of the double-sided image was set such that when the high-quality paper was watermarked with light, the double-sided image overlapped and the image before the image was divided into two was seen.

(Transparent verification)
When the printed matter produced was viewed through one side at a distance of 2.0 m from a 40 W fluorescent lamp, a glittering lattice illusion appeared.
The relative density of the printed matter in the state viewed through the light was equivalent to D = 1.50 in the square part (high density area 11) and D = 0.30 in the gap part (medium density area 12) (FIG. 2). ). The relative density referred to here is the density when the density of the circular portion (low density region 13) is D = 0.

(Reflection verification)
When the produced printed matter was viewed from one side and the other side only with the reflected light, the square part was seen on one side with a relative density D = 1.50, and the gap part was seen with a relative density D = 0.05. On the other side, the square portion was seen at a relative density D = 0.05, and the gap portion was seen at a relative density D = 1.50, and no glittering lattice illusion was developed. The relative density referred to here is the density when the density of the circular portion is D = 0.
It was confirmed that the printed material exhibited a glittering lattice illusion by seeing it through the light.

DESCRIPTION OF SYMBOLS 1 ... Anti-counterfeit medium 2 ... Base material 3 ... 1st pattern 4 ... 2nd pattern 5, 6 ... Protective layer 10 ... Anti-counterfeit pattern 11 ... High concentration area | region 12 ... Medium concentration area | region 13 ... Low concentration area | region

Claims (4)

An anti-counterfeit medium having a base material, a first pattern provided on one surface of the base material, and a second pattern provided on the other surface of the base material,
An anti-counterfeiting pattern that expresses an illusion is formed by the first pattern and the second pattern in a state in which the anti-counterfeit medium is observed through light with one side of the substrate facing forward. Yes,
The anti-counterfeit medium, wherein the second pattern is provided by calculating a decrease in density when the anti-counterfeit medium is watermarked with light on one side of the substrate.   The anti-counterfeit medium according to claim 1, wherein the anti-counterfeit pattern includes a high concentration region, a medium concentration region, and a low concentration region.   The high-concentration region is composed of the first pattern, the medium-concentration region is composed of the second pattern, and the low-concentration region is provided on both sides of the substrate with the first pattern and the second pattern. The anti-counterfeit medium according to claim 2, wherein the medium is configured by a portion not formed. A method for producing an anti-counterfeit medium comprising a base material, a first pattern provided on one surface of the base material, and a second pattern provided on the other surface of the base material,
The anti-counterfeit medium is a forgery-preventing pattern that expresses an illusion with the first pattern and the second pattern in a state where the anti-counterfeit medium is observed through light with one side of the substrate facing forward. Is formed,
A first pattern forming step of forming a first pattern on one surface of the substrate;
The second pattern is formed on the other surface of the base material by calculating a decrease in density when the one surface of the base material is facing forward and the anti-counterfeit medium is watermarked with light. A method for producing a forgery prevention medium.

Images