JPH1081058A - Copy preventing medium and method for producing the same - Google Patents

Abstract

(57) [Problem] To provide a printed matter having an effect of preventing forgery by a color copying machine and a method for producing the same. A latent pattern is formed on at least two types of light reflecting portions having different reflectances on a copy prevention medium surface, and the latent pattern is made visible by a color copy machine. In the method of forming a latent pattern, a metal thin film layer 13 is provided on the entire surface of a substrate 11, and a light transmitting layer 12 for controlling the amount of transmitted light according to a predetermined pattern is provided. Alternatively, the first light transmitting layer 12-1 is provided on the entire surface, and the second light transmitting layer 12-2 is provided thereon according to a predetermined pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copy protection medium having a function of discriminating a copy which has been forged or falsified by using a copying machine, and a method for producing the same.

[0002]

2. Description of the Related Art Banknotes, gift certificates, stock certificates, receivables, etc., such as banknotes, gift certificates, stock certificates, bonds, etc., which should have been subjected to advanced counterfeiting measures in recent years due to technological advances in copying machines such as color copiers. , Admission tickets, invitation tickets, commuter passes, and copies of copy-prevention media such as ID cards have come to market and have become a social problem. As a method of suppressing forgery using these copying machines, it has been conventionally known to form a part of information on a copy prevention medium using silver ink made of aluminum powder or the like. Even if the copy prevention medium using the silver ink is forged by a copying machine such as a color copier, the silver color of the glossy silver ink is not reproduced in the copy. Therefore, by looking at the silver color of the silver ink,
Since it is possible to determine whether a copy is a forged copy using a copying machine, silver ink has an effect of preventing forgery. Similarly, a hologram or a diffraction structure of a diffraction grating cannot be reproduced by a copying machine, and is provided on a part of a copy protection medium. Diffraction structures such as holograms and diffraction gratings can change the diffraction light dynamically by changing the observation direction and illumination direction. The authenticity of the copy prevention medium can be determined. Further, in Japanese Patent Application Laid-Open No. 7-309062, two types of halftone dots formed at different screen rulings having different pitches and having the same density are adjacently formed in a pattern so that they cannot be visually discriminated. It has been proposed to provide for copy protection media. When this copy protection medium is copied by a copying machine such as a color copying machine, the low resolution of the copying machine causes
The density balance of the different types of halftone dots has collapsed, and patterns have become apparent.

[0003]

The silver ink is obtained by mixing a flat metal powder made of aluminum or the like with a transparent vehicle, and has a variation in the direction of the flat metal powder. Therefore, from a macro perspective, the reflective surface of the silver ink is a rough surface. On the other hand, a color copier irradiates light from a light source at an angle of 45 degrees with respect to the normal to the surface of the copy object, and a light receiving unit installed at a direction of 0 degrees with respect to the normal to the surface. The scattered light from the surface is received, and the information of the copy object is reproduced according to the received light intensity.
Therefore, the reflection surface of the silver ink scatters and reflects light from the light source of the color copier, and makes a part of the reflected light incident on the light receiving portion of the color copier. Based on the intensity of this incident light, the color copier replaces the silver ink portion of the copy with
The reproduction is reproduced in a light grayish hue without gloss.
However, such a change in which the silver color with a weak shine of silver ink is reproduced in light gray in a copy is lacking in its own impact, so some people do not notice this change and copy the copy. May be mistaken for a genuine copy-prevention medium, and with such a change, there is a problem that counterfeiting by a copying machine cannot be suppressed. Also, when a hologram or a diffraction grating is provided in a part of the copy protection medium, the reproduced image of the hologram or the diffraction grating in the direction of 0 degree by the illuminating light incident from the direction of 45 degrees due to the structure of the color copier described above. Is reproduced on a copy. By the way, in the work of discriminating a copy in a short time at the time of congestion or the work of discriminating a copy in darkness,
A dynamic change in diffracted light due to the diffractive structure cannot be sufficiently confirmed, and there is a problem that a copy is mistaken for a real copy prevention medium. Furthermore, the method proposed in Japanese Patent Application Laid-Open No. 7-309062 relies on the resolution of the copying machine, so that the anti-counterfeiting effect is reduced as the performance of the copying machine, such as the resolution and reproducibility, is improved. There is a problem that is expected. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide a copy prevention medium and a method for preparing the same, which can easily perform the authenticity discrimination work only by visual observation.

[0004]

A copy protection medium according to the present invention is a copy protection medium including a first light reflection section and a second light reflection section, wherein the first light reflection section and the second light reflection section are provided. The light reflecting portion has a metal thin film layer, and a first light transmitting layer for limiting an amount of light incident on the metal thin film layer is formed in the second light reflecting portion, and formed in the first light reflecting portion. Since it is not performed, the reflectance of the first light reflecting portion and the reflectance of the second light reflecting portion can be made different. If the first light reflecting portion has the second light transmitting layer that limits the amount of light incident on the metal thin film layer, the reflectance of the first light reflecting portion can also be controlled. If the light transmitting layer contains fine particles, the reflectance can be controlled by selecting the type or amount of the fine particles. If a latent pattern is formed by the first light reflecting portion and the second light reflecting portion provided adjacent to each other, the reproduction state of the first light reflecting portion and the second light reflecting portion in the copy , A latent pattern appears. A first light reflecting portion and a second light reflecting portion;
If a camouflage pattern is formed on the light reflecting portion, the difference in reflectance between the first light reflecting portion and the second light reflecting portion in the copy protection medium can be camouflaged. Individual information may be formed on the first light reflecting portion and the second light reflecting portion. Further, a method for producing a copy prevention medium according to the present invention is a method for producing a copy prevention medium having a first light reflection portion and a second light reflection portion, wherein a step of preparing a base material, Forming a metal thin film layer, forming a first light transmission layer on a part of the metal thin film layer, and removing the metal thin film layer on which the first light transmission layer is not formed by a first light transmission layer. Since the method includes a light reflecting portion and a step of using the metal thin film layer on which the first light transmitting layer is formed as a second light reflecting portion, the reflectance of the first light reflecting portion and the second light A copy prevention medium having a different reflectance from the reflecting portion can be produced.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram for explaining the principle of a copy protection medium according to the present invention. Generally, in a copying machine, as shown in FIG. 1, light is radiated from a light source at an angle of 45 degrees with respect to the normal to the surface of the object to be copied, and the light is reflected and scattered on the surface of the object to be copied. Among the lights, there is adopted a method in which light reflected at an angle of 0 degrees with respect to the normal is received by a light receiving unit provided in that direction, the received light intensity is read, and the received light intensity is reproduced. In the present application, all angles are angles with respect to a normal line.
In addition, many copy-preventing media, which are to be copied, are multi-color printed. In a color copier, for each component of the three primary colors, the reflected light from the surface of the copy received at the light receiving unit is received. The received light intensity is measured, and the density gradation and color tone of the copy are reproduced according to the received light intensity. FIG. 1A is a diagram showing a case in which general white paper is used as a copy object. The illumination light is reflected and scattered on the surface of the copy object, and only the light reflected in the angle direction of 0 degrees reaches the light receiving unit, and the light receiving intensity is measured. Based on the received light intensity, the density gradation and color tone of the copy are reproduced on the copy. For general white paper,
The distribution of the reflected scattered light is substantially uniform, and the reflectance in the 0-degree angle direction is larger than that of silver ink or metallic luster described later, and is reproduced white in a copy by a copying machine. On the other hand, FIG. 1B is a diagram showing a case where a metallic glossy surface such as a mirror surface is used as a copy object. The illuminating light emitted at an angle of 45 degrees is specularly reflected at an angle of -45 degrees on a metallic glossy surface. do not do. Therefore, the metallic glossy surface is reproduced black on the copy by the copying machine. FIG. 1C is a diagram showing a case where the printing surface using silver ink is a copy object. The printing surface with silver ink,
The distribution of the reflected scattered light is more deviated in the regular reflection direction than general white paper, and exhibits an intermediate characteristic between general white paper and a metallic glossy surface. It is an intermediate value. Therefore, the printed surface of the silver ink is reproduced by the copier in a light gray color with no shine on the copy. The shine of the metallic glossy surface or the printing surface by silver ink is such that part of the light emitted from various angles is specularly reflected on the metallic glossy surface or the surface of the metal powder of the silver ink, and this reflected light is Because it comes into my eyes. By the way, a copier such as a color copier cannot receive regular reflection light and cannot reproduce a regular reflection surface due to its structure, and therefore cannot reproduce these glossy surfaces. Here, the ratio of the reflected light in the 0-degree angle direction of the copy to the illumination light from the light source provided in the 45-degree angle direction of the color copier, that is, the 45-degree irradiation and the 0-degree reflectance (Hereinafter, referred to as “reflectance 45-0”) can be expressed by the following equation. Reflectivity 45-0 = 0 reflected light amount at 0 degree / irradiated light amount at 45 degree × 100

The reflectance 45-0 of the light reflecting portion formed on the surface of the copy and the visual sensation, the reflection density and the visual sensation of the light reflection portion reproduced on the copy by the copying machine, and the Table 1 shows the results of examining the evaluation of the difference from the copy.

[Table 1] The light reflecting portion of the object to be copied as the sample for the above measurement is an aluminum-deposited surface, and by controlling the surface roughness of the substrate on which aluminum is deposited, light reflecting portions having different reflectivities of 45-0 are obtained. Was. The measurement of the reflectance 45-0 of the light reflection portion of the copy was performed using a visual filter with a Macbeth print contrast meter "PCM-2". Hereinafter, all values of the reflectance 45-0 are measured values by this apparatus. The reflection density of the light reflection portion reproduced in the copy was measured by a Macbeth reflection densitometer RD-918S (visual filter). This reflection densitometer irradiates illumination light from an angle direction of 45 degrees, receives a light amount reflected in an angle direction of 0 degrees, and performs reflection density conversion. Further, the column of visual sensation visually expresses the light reflection portion in the copy, and the reproduced light reflection portion in the copy, and the column of evaluation includes the light reflection portion of the copy and the copy. The light reflection portion reproduced in step (1) was shown to ten humans, and at a glance, it was confirmed whether or not a copy could be discriminated, and the number of discriminated persons was described. From Table 1, if the light reflecting portion of the copy is reproduced in black or dark gray with no shine in the copy, the difference becomes obvious, so that anyone can see the difference and copy the copy. Even a person who is not familiar with the object notices the abnormality of black or dark gray reproduced in the copy, so that the light reflecting portion has a function of authenticity determination. However, in the case where the object to be copied has only a single light reflecting portion, when copying with a copying machine such as a color copying machine, if the copy density is adjusted based on the reproduction color of the light reflecting portion in the copy. For example, in some cases, the light reflecting portion is reproduced in gray, and a person who does not know the copy cannot clearly determine whether or not the copy has been copied. Therefore, in the present invention, by providing two or more types of light reflecting portions having different reflectances on the copy-preventing medium, it is difficult to forge by adjusting the copy density and to reproduce the two or more types of light reflecting portions in the copy. Depending on the state, it can be clearly judged visually that the copy is a copy.

FIG. 2 is a plan view showing a copy protection medium according to the present invention. Hereinafter, for the sake of easy understanding, the “first light reflecting portion” has a reflectivity of 45−− more than the “second light reflecting portion”.
Description will be made assuming that 0 is small. As shown in FIG. 2A, the copy protection medium 1 includes an individual information display area K and a latent pattern area S. Individual information display area K
For example, if it is a bank note, it consists of characters such as amount, serial number, name of factory, etc., and figures such as a person image, Bank of Japan seal, Ayamon, etc. Individual information 4 unique to the medium itself is provided by appropriate means such as printing or printing. In the latent pattern region S, two types of light reflecting portions having different reflectivities 45-0, that is, a first light reflecting portion A and a second light reflecting portion B are provided adjacent to each other. A latent pattern 3 is formed by the boundary between the light reflecting portions A and B. Latent pattern 3
May be appropriately selected from warning characters or marks such as "copy", "fake", and "invalid". The light reflecting portions A and B
Is such that the difference between the light reflecting portions A and B in the copy protection medium can be overlooked by visual observation. Preferably in the range of 10 to 10 percent,
A range of 3 to 5% is desirable from the balance between the two. Here, the difference between the reflectances 45-0 of the light reflecting portions A and B is
If it exceeds 10%, it is a genuine copy protection medium 1.
However, since the latent pattern 3 that must be difficult to see becomes apparent and can be easily identified by visual inspection, the copy prevention medium may be mistaken for a copy. Further, if the difference between the reflectances 45-0 of the light reflecting portions A and B is less than 2%, even a copy copied by a color copier becomes apparent due to the difference in reflectance between the two light reflecting portions. In some cases, the latent pattern 3 that should be performed does not become apparent, and the copied matter cannot be easily recognized. Further, in order to make the latent pattern 3 of the copy preventing medium 1 more difficult to recognize, the camouflage pattern 5 composed of fine characters, patterns, wavy lines, etc.
Is formed by printing.

FIG. 2B is a view showing a copy 2 obtained by copying the copy protection medium 1 shown in FIG. 2A by a copying machine such as a color copying machine. The individual information display area K ′ of the copy 2 is reproduced almost in the same manner as the individual information display area K of the copy protection medium 1. On the other hand, in the reproduction area S 'of the latent pattern area of the copy 2 corresponding to the latent pattern area S of the copy protection medium 1, as shown in FIG. 2B, the reproduction area A' of the first light reflection portion A. Due to the difference in the reproduction state of the reproduction area B ′ of the second light reflection portion B, the latent pattern 3 that was difficult to see on the copy prevention medium 1 becomes apparent in the copy 2 and easily becomes a check pattern 3 ′. You will be able to see it visually. The manifestation of this latent pattern 3
Unlike a delicate change in density or color tone of a specific portion of the copy protection medium 1, a pattern that is difficult to see on the copy protection medium 1 appears in a copy, and therefore has an impact. Therefore,
Even if a person who is not familiar with the copy protection medium 1 can see the abnormality just by looking at the copy, the function of judging the copy by this manifestation has a great effect.

Further, as described above, a metallic glossy surface such as an aluminum vapor-deposited surface is reproduced as light gray in a copy when the reflectance 45-0 exceeds 30% and becomes 40 to 50%. The function of determining a copy is reduced. However, by having two types of light reflecting portions as in the copy prevention medium of the present invention, even if the reflectance 45-0 exceeds 30%, the copy does not have a thin fog on the reproduced light reflecting portion. Has occurred, but in that,
The reproduction areas of the two light reflecting portions having different densities are in a state of being seen. When the reflectance 45-0 of the light reflection portion exceeds 30%, the light reflection portion becomes slightly glossy, and unnaturalness when the entire copy protection medium is viewed is reduced.

Here, the location of the copy protection medium 1 where the latent pattern 3 is provided is not limited to the example of FIG. 2A, and may be any position on the copy protection medium 1. It is preferable to provide the forged copy in a place where the copy is easily noticeable using a copying machine. Further, the latent pattern display area S and the individual information display area K do not need to be partitioned as shown in FIG. 2A, and may overlap as appropriate, and the individual information display 4 is placed on the light reflecting portions A and B. May be provided.

Next, a method for producing a copy protection medium according to the present invention will be described. FIG. 3 is a schematic cross-sectional view for explaining the latent pattern area S of the copy protection medium 1 according to the present invention. The embodiment shown in FIG.
A metal thin film layer 13 is formed by a vacuum evaporation method, and then a light transmitting layer 12 for limiting the amount of light incident on the metal thin film layer 13 is provided in a part on the metal thin film layer 13 in a pattern, The portion where the light transmitting layer 12 is formed is referred to as a second light reflecting portion B, and the portion where the light transmitting layer 12 is not formed is referred to as a first light reflecting portion A. The amount of light incident on the second light reflecting portion B is smaller than the amount of light incident on the first light reflecting portion A due to scattering or absorption in the light transmitting layer 12. The reflected light from the second light reflecting portion B further includes
Under the influence of the light transmitting layer 12, the amount of light is further reduced as compared with the reflected light from the first light reflecting portion A. Substrate 1
As 1, any material having good adhesion to metal can be used, and for example, a plastic sheet of a polyethylene terephthalate sheet can be used. Further, even those having poor adhesion to metal can be used by providing an anchor layer such as a polyester resin between the base material 11 and the metal thin film layer 13. Furthermore, like high quality paper,
If the material has permeability and the surface condition is not good, a filler layer made of a vinyl chloride-vinyl acetate copolymer resin or the like may be provided. When the surface of the substrate 11 is not smooth, the metal thin film layer 13
Since it has a constant reflectivity 45-0, an anchor layer is provided between the base material 11 and the metal thin film layer 13, and the reflectivity of the metal thin film layer 13 is determined by the amount and particle size of fine particles added to the material of the anchor layer.
−0 can be controlled. As the light transmission layer 12,
If the amount of light incident on the metal thin film layer is limited, it may be transparent or translucent. A mixture of fine particles such as above and a synthetic resin such as a polyester resin can be used. Further, the light transmitting layer may be colored with a colorant such as a dye or a pigment. The light transmitting layer 1
2 is provided on the upper side of the metal thin film layer 13 and thus needs to be transparent or translucent. Therefore, when adding an inorganic pigment as fine particles, the amount of the inorganic pigment is limited to a level that does not impair the transparency of the light transmitting layer 12. There is a need. As the metal thin film layer 13, a material that reflects metal, for example, a metal such as aluminum can be used, and has a thickness enough to reflect light, for example, 2
It is formed with a thickness of 00 to 1000 angstroms.
The metal thin film layer 13 can be formed by a thin film forming means such as a vacuum evaporation method and a sputtering method. Instead of a simple metal such as aluminum, a transparent metal compound having a high refractive index such as zinc sulfide may be used as the metal thin film layer 13. A metal compound having a high refractive index reflects a part of incident light in a specular reflection direction due to a difference in refractive index at an interface, so that a copy of a portion where a metal compound is formed is compared with a portion where no metal compound is formed. It is reproduced with darkness. A metal compound having a high refractive index does not have a metallic luster in a copy protection medium like a metal simple substance, and the naturalness as a copy protection medium increases. The embodiment shown in FIG.
In the embodiment of FIG. 3A, the first light transmitting layer 12-
1 and the metal thin film layer 13, a second light transmission layer 12-2
Is formed. The reflectance of the first light reflecting portion A is determined by the second light transmitting layer 12-2,
The reflectance of the second light reflecting portion B is determined by the first light transmitting layer 12-1 and the second light transmitting layer 12-2. By providing the second light transmission layer 12-2 in this manner, the entire reflectance 45-0 of the copy protection medium can be reduced, and a copy protection medium with less discomfort can be produced.
The first light transmitting layer 12-1 and the second light transmitting layer 12
As -2, the one used for the light transmission layer 12 described above can be used. In the embodiment shown in FIG. 3C, a metal thin film layer 13 is formed on a rough substrate (having a large surface roughness) 14 by vapor deposition of a metal. By forming the first light transmission layer 12-1 in a pattern, two types of light reflection portions having different reflectances 45-0, that is, the first light reflection portion A and the second light reflection portion B are formed. can get. This embodiment is similar to the embodiment of FIG.
The overall reflectance 45-0 of the copy prevention medium can be increased, and a copy prevention medium with less discomfort can be created. Any rough substrate can be used as long as it has a rough surface. For example, a plastic sheet of a rough polyethylene terephthalate sheet containing fine particles such as pigments can be used.
Instead of a rough plastic sheet, a sheet obtained by subjecting a smooth surface of a base material to a roughening treatment can also be used.

FIG. 4 is a sectional view showing the completed copy preventing medium. The copy protection medium 1 includes a metal thin film layer 13 and a first
A camouflage pattern printing layer 15 on the light transmitting layer of
Is printed by a printing method such as offset printing or silk printing.
Further, a protective layer 16 made of a polyester resin, an acrylic resin, or the like is provided. Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the invention. For example, the number of the light reflecting portions may be three or more instead of two. Although not shown, the protective layer 16
An individual information printing layer may be provided above or below by printing or printing. Further, as the protective layer 16, a transparent ink or a transparent plastic film may be laminated, or a colored layer in which a dye or a pigment is mixed in a polyester resin or an acrylic resin may be provided. When the light transmitting layer is colored, if the protective layer is also colored with a similar color, the difference between the first light reflecting portion and the second light reflecting portion becomes difficult to recognize visually.

(Example 1) A transparent anchor agent composed of a polyester resin was formed to a thickness of 1 μm by gravure printing on a base material composed of a white polyethylene terephthalate sheet having a thickness of 188 μm. Next, on this anchor agent, aluminum was vacuum-deposited to a thickness of 500 angstroms to provide a metal thin film layer. On this metal thin film layer, a light transmitting layer in which 10 parts by weight of fine particles made of microsilica were mixed with 100 parts by weight of a binder made of an acrylic resin by offset printing so that the light transmittance became 70%. , A background pattern excluding the character portion of “COPY” is provided with a thickness of 1.5 μm, and a latent pattern including a first light reflection portion having a character shape of “COPY” and a second light reflection portion of the background is formed. Formed. Next, a camouflage pattern printing layer including a color pattern was formed by offset printing. Further, a protective layer was provided by offset printing on the camouflage pattern printing layer to complete a copy prevention medium. At this time, the reflectance of the first light reflecting portion is 45−
0 was 14%, and the reflectance 45-0 of the second light reflecting portion was 20%. In the copy prevention medium thus created, the latent pattern “COPY” composed of the boundary between the first light reflecting portion and the second light reflecting portion.
Was difficult to determine visually. When this copy protection medium was copied using a color copier (CLC500, manufactured by Canon), the latent pattern “COP
The letter "Y" became apparent, and it could be easily identified as a copy.

(Example 2) On the metal thin film layer of (Example 1) described above, one of
5 parts by weight of fine particles made of calcium stearate are mixed with 00 parts by weight, and gravure printing is performed so that the light transmittance of the second light transmitting layer becomes 80%.
Provided with a thickness of 1 μm on the entire surface, and on this second light transmitting layer,
Similarly to (Example 1), a light transmitting layer is provided, and a first light reflecting portion in which only the second light transmitting layer is provided, a light transmitting layer, and a second light transmitting layer are provided. 2 light reflecting portions were formed. At this time, the reflectance 45-0 of the first light reflecting portion is 1
8%, and the reflectance of the second light reflecting portion is 45-0.
Was 26 percent. In the copy prevention medium thus created, the latent pattern “COPY” formed by the boundary between the first light reflecting portion and the second light reflecting portion was difficult to visually discriminate. When the copy preventing medium was copied with a color copying machine (CLC500, manufactured by Canon), the character "COPY" as a latent pattern became apparent, and it could be easily identified as a copy.

Example 3 A white polyethylene terephthalate sheet having a center line average roughness (hereinafter referred to as Ra) of 0.20 μm and a thickness of 188 μm was used in place of the base material and the anchor layer of the above-mentioned (Example 1). Was directly vacuum-deposited with aluminum to a thickness of 500 angstroms to provide a metal thin film layer. Next, similarly to (Example 1), a light transmitting layer was provided. At this time, the reflectance 45-0 of the first light reflecting portion was 28%, and the reflectance 45-0 of the second light reflecting portion was 34%. In the copy prevention medium thus created, the first
The latent pattern “COPY” composed of the boundary line between the light reflection portion and the second light reflection portion was difficult to visually discriminate. Also, this copy protection medium is transferred to a color copier (C
When the image was copied using an LC500 (manufactured by Canon Inc.), the character "COPY" as a latent pattern became apparent, and it could be easily identified as a copy.

[0016]

As described above, in the copy protection medium according to the present invention, the first light transmitting layer for limiting the amount of light incident on the metal thin film layer is formed on the second light reflecting portion. Since it is not formed on the first light reflecting portion, the reflectance of the first light reflecting portion and the reflectance of the second light reflecting portion can be made different from each other. A difference occurs in the reproduction state between the copy-preventing medium and the second light-reflecting part, making it difficult to forge by adjusting the density of the copying machine. In addition, it is possible to visually determine that the copy is a copied one, and Can be prevented, and the use of a copy can be prevented. If the first light reflecting portion has the second light transmitting layer for limiting the amount of light incident on the metal thin film layer, the reflectance of the first light reflecting portion can also be controlled, The first light reflecting portion and the second light reflecting portion can have a desired reflectance difference in a desired reflectance region. If the light transmitting layer contains fine particles, the reflectance can be easily controlled by selecting the type or amount of the fine particles.
If the latent pattern is formed, the first in the copy
Due to the difference in the reproduction state between the light reflecting portion of the second light reflecting portion and the second light reflecting portion,
Since the latent pattern appears, even a person who does not know the genuine copy protection medium can easily determine the copy. If a camouflage pattern is formed,
Since the difference in reflectance between the first light reflection portion and the second light reflection portion in the copy prevention medium can be camouflaged, the difference between the two light reflection portions of the genuine copy prevention medium is visually determined. Can be garnished. Further, a method for producing a copy prevention medium according to the present invention is a method for producing a copy prevention medium having a first light reflection portion and a second light reflection portion, wherein a step of preparing a base material, Forming a metal thin film layer, forming a first light transmission layer on a part of the metal thin film layer, and removing the metal thin film layer on which the first light transmission layer is not formed by a first light transmission layer. Since the method includes the step of forming a light reflecting portion and the step of forming a metal thin film layer on which a first light transmitting layer is formed as a second light reflecting portion, the reflectance of the first light reflecting portion and the second light Since the reflectance of the reflecting portion is different, a difference occurs in the reproduction state between the first light reflecting portion and the second light reflecting portion in the copy, making it difficult to forge by adjusting the density of the copying machine, and Can be clearly judged visually by copying, and forgery of copy-prevention media by copier It is possible to suppress, able to create a copy prevention medium that can prevent the use of copied material.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of a copy protection medium according to the present invention.

FIG. 2 is a plan view showing a copy protection medium according to the present invention.

FIG. 3 is a schematic cross-sectional view for explaining a latent pattern area S of the copy protection medium according to the present invention.

FIG. 4 is a sectional view showing a completed copy prevention medium.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 copy prevention medium 2 copy 3 latent pattern 3 ′ check pattern 4 individual information 5 camouflage pattern 11 base material 12 light transmission layer 12-1 first light transmission layer 12-2 second light transmission layer 13 metal thin film layer 14 Rough surface base material 15 Camouflage pattern printing layer 16 Protective layer A First light reflection part B Second light reflection part A 'Reproduction area of first light reflection part B' Reproduction area of second light reflection part K Individual information display area K 'Reproduction area of individual information display area S Latent pattern area S' Reproduction area of latent pattern area

Claims (7)

[Claims] An anti-copying medium including a first light reflecting portion and a second light reflecting portion, wherein the first light reflecting portion and the second light reflecting portion have a metal thin film layer. And a first light transmitting layer for limiting an amount of light incident on the metal thin film layer,
A copy prevention medium, which is formed on the light reflection portion of (1), but is not formed on the first light reflection portion. 2. The copy preventing medium according to claim 1, wherein said first light reflecting portion has a second light transmitting layer for limiting an amount of light incident on said metal thin film layer. 3. The copy protection medium according to claim 1, wherein the light transmitting layer contains fine particles. 4. The copy protection medium according to claim 1, wherein a latent pattern is formed by the first light reflection portion and the second light reflection portion provided adjacent to each other. . 5. The copy prevention medium according to claim 1, wherein a camouflage pattern is formed on the first light reflecting portion and the second light reflecting portion. 6. The copy protection medium according to claim 1, wherein individual information is formed on the first light reflecting portion and the second light reflecting portion. 7. A method for producing a copy prevention medium having a first light reflecting portion and a second light reflecting portion, comprising: preparing a base material; and forming a metal thin film layer on the base material. Forming a first light transmitting layer on a part of the metal thin film layer; and forming the metal thin film layer on which the first light transmitting layer is not formed as a first light reflecting portion. Step, the metal thin film layer on which the first light transmitting layer is formed
Forming a copy preventing medium.