JP3139255B2 - sticker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal, and more particularly, to a seal for preventing forgery or tampering which is difficult.

[0002]

2. Description of the Related Art Conventionally, countermeasures against forgery are made by making it difficult to imitate the article itself, or by attaching an object that is difficult to imitate to the article as proof of authenticity. Some things make it possible to distinguish between genuine and fake. For example, the former applies fine processing to itself, such as securities such as banknotes, or applies a color tone that is difficult to imitate, or makes the material special, improper use of imitation or printing technology, or copying machines This makes it difficult to prevent forgery caused by illegal copying by the company. Furthermore, advances in print duplication technology and digital technologies such as copiers have made it possible to easily reproduce even the fine processing described above, even if it is difficult to imitate colors. Correspondingly, there is a trend to make the processing technology higher and finer and to make duplication and forgery more difficult.

[0003] The latter is easy to handle because it is merely attached to an article, and thus has become widely used. For example, there is a seal on which an image formed of a relief hologram is formed. This has the effect that a hologram image is formed in an uneven shape and mass production is possible by embossing. In particular, considering the layer configuration, it is configured to make the seal difficult to peel or difficult to regenerate after peeling, and once it is attached to cards, bills, certificates, etc. as an object to be used, The fact that a part or the whole of the hologram is destroyed makes it possible to determine at a glance that not only counterfeiting but also tampering with the object has been done.

[0004] Further, in the case of a seal provided with a forgery prevention function, there are demands for easily determining whether the seal is genuine or fake, making it difficult to determine the configuration of the seal itself, and preventing the forgery prevention function from being changed by the surrounding environment. is there.

[0005]

However, the true / false discrimination by advanced miniaturization is overlooked if the microscopic part is enlarged or compared with the genuine one unless it is carefully observed. In addition, it is becoming difficult to meet the actual transaction conditions, such as the need to take sufficient time for the location and confirmation of the location. Further, even if the material is special, it cannot be made a completely unique material, and the cost is high, which is not realistic. Further, the hologram as described above has a simple structure such as a hologram principle and a layer, and is likely to be forged, so that the effect of preventing forgery is weakened.

Accordingly, the present invention is a forgery prevention seal having a unique color tone which makes it difficult to determine the layer structure and constituent materials, and which can identify the authenticity. An object of the present invention is to provide an optical forgery prevention transfer foil formed by laminating ceramics that can be transferred to a three-dimensional object such as a molded body.

[0007]

According to the first aspect of the present invention, a functional layer is provided on a substrate, and an adhesive layer is laminated on the same side or a different side, and the functional layer has a high refractive index. This is a seal formed by laminating a plurality of ceramic materials having different refractive indices of a refractive index and a low refractive index.

According to a second aspect of the present invention, based on the premise of the first aspect, the functional layer is a laminate of ceramic materials having different refractive indices, and has a high refractive index layer and a low refractive index layer. The seal is characterized by alternately arranging combinations of the following.

According to a third aspect of the present invention, based on the premise of the first aspect, the functional layer is made of magnesium fluoride, calcium fluoride, cerium fluoride, aluminum fluoride, silicon dioxide, aluminum oxide or oxide oxide. A seal characterized by being a laminate comprising a combination of any one of magnesium and any one of zinc sulfide, zirconium dioxide, titanium dioxide, cerium dioxide, tantalum oxide, zinc oxide, and indium oxide.

According to an eleventh aspect of the present invention, based on the premise of the first aspect, the functional layer is a laminate of ceramic materials having different refractive indexes, and a colored layer is provided on the surface on the adhesive layer side. It is a seal characterized by the following.

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

According to the seal of the present invention, the functional layer has a property of reflecting or transmitting light in a specific wavelength region by alternately combining ceramics having a low refractive index and a ceramic having a high refractive index. By changing the thickness, the thickness of the functional layer changes, so that the wavelength region shifts and the color looks different, which makes it easy to determine.

By forming a colored layer in the lower layer,
The seal can be colored without affecting the color change of the transmitted or reflected light, making it easier to see,
In addition, the type of color can be selected.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a seal according to the present invention, FIG. 2 is a sectional view showing the structure of a seal according to another embodiment of the present invention, and FIG. 3 is another embodiment of the present invention. FIG. 4 and FIG. 5 are graphs showing the visible spectrum of a functional layer by the seal of the present invention.
FIG. 6 is a graph showing a visible spectrum of a functional layer with a seal as a comparative example for the transfer foil for forgery prevention of the present invention.

FIG. 1 shows a seal 1 of the present invention.
A functional layer 3 and an adhesive layer 4 are sequentially laminated thereon. The functional layer 3 is a ceramic layer including a high refractive index layer 6 and a low refractive index layer 7. The protective layer 8 can be provided on the opposite surface side of the base material 2 as needed.

FIG. 2 shows a seal 1 according to another embodiment of the present invention.
FIG. 1 is a cross-sectional view showing a configuration of a device, in which a functional layer, a coloring layer, and an adhesive layer are sequentially laminated on a base material. The functional layer 3 is a ceramic layer including a high refractive index layer 6 and a low refractive index layer 7. The protective layer 8 can be provided on the opposite surface side of the base material 2 as needed.

FIG. 3 is a sectional view showing the structure of a seal 12 according to another embodiment of the present invention.
The protective layer 8 is sequentially laminated, and the adhesive layer 4 is provided on the opposite side of the substrate 2. The functional layer 3 is a ceramic layer including a high refractive index layer 6 and a low refractive index layer 7. Further, the colored layer 9 of FIG. 2 can be provided between the base material 2 and the functional layer 3. Further, the protective layer 8 can be provided as needed.

When the functional layer 3 is viewed through the substrate 2, the substrate 2 needs to have sufficient transparency, and furthermore, it is sufficient that the substrate has a certain degree of rigidity and surface smoothness. However, for example, a polymer film such as a polyester film and a polyolefin film can be used.

The protective layer 4 can be selected from various compositions depending on the application and purpose as long as it does not affect the functional layer 3. For example, polyolefin, polyvinyl chloride, polyvinylidene chloride, polyvinyl An optically transparent material such as alcohol or plastic such as polyethylene terephthalate is laminated.

The functional layer 3 is formed by alternately laminating a plurality of ceramics having different refractive indexes with a specific thickness.
As the low refractive index layer 7, magnesium oxide (refractive index n =
1.6), silicon dioxide (n = 1.5), magnesium fluoride (n = 1.4), calcium fluoride (n = 1.3 to
1.4), cerium fluoride (n = 1.6), aluminum fluoride (n = 1.3), aluminum oxide (n = 1.
6) and titanium dioxide (n = 2.4) and zirconium dioxide (n = 2.
0), zinc sulfide (n = 2.3), cerium dioxide (n =
2.3) A composite layer in which one of indium oxide (n = 2.0), tantalum oxide (n = 2.1), and zinc oxide (n = 2.1) is laminated in a predetermined thickness. It is. The functional layer 3 may be provided with a plurality of layers composed of the above combinations. In this embodiment, materials other than those listed above can be used as long as they satisfy the lamination conditions of the constituent layers.

By reflecting or transmitting a light beam in a predetermined wavelength range to the functional layer 3 and changing the viewing angle, the optical path length in the thin film changes, and the color of the transmitted light or the reflected light appears to change. . Thereby, anti-counterfeiting properties are exhibited. Since the protective layer 8 of the seal 1 of FIG. 1 is an organic polymer and has a low refractive index, the next layer in contact with the protective layer 8 preferably has a high refractive index. Generally, spectral characteristics change according to the number of layers. The transfer foil 1 for preventing forgery of this embodiment has an even number of layers including the protective layer 8, but has an odd number of functional layers. Further, by providing the colored layer 9 with ceramic or colored transparent ink, the color change becomes diversified and easy to see, so that the forgery prevention effect is improved.

As long as the thickness of the functional layer 3 can be controlled, any film forming method can be used. Above all, the dry method is superior for the production of thin films, such as ordinary vacuum vapor deposition, physical vapor deposition such as sputtering, and CVD.
A chemical vapor deposition method such as the method can be used.

The total thickness of the functional layer 3 is desirably 1 μm or less. If it exceeds 1 μm, the flexibility becomes poor, and the functional layer 3
This is because cracks may be generated in the case.

When the functional layer 3 is in contact with the functional layer 3, the adhesive layer 4 may be a commonly used one that does not alter or damage the functional layer 3. For example, a vinyl chloride-vinyl acetate copolymer, an acrylic adhesive, a polyester-based adhesive may be used. Examples include, but are not limited to, polyamides.

The present invention will be described in detail with reference to examples.

In addition, the visible spectrum of the prepared seal of the present invention and the seal prepared for comparison with the seal of the present invention were measured with an invisible / visible spectrophotometer, and a peeling test of the functional layer 3 from the substrate was performed. Was performed by sticking and peeling of an adhesive tape, and the peeled state was evaluated.

Example 1 A polyester film having a thickness of 25 μm was used for the base material 2, silicon dioxide was used for the low refractive index layer 7, and zinc sulfide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal.

Table 1 shows the seal configuration, the state of the layers, and the evaluation results of this example. FIG. 4 shows the visible spectrum of this seal. The center wavelength of visible light absorption perpendicular to the film was 550 nm, and when visible light was incident from an angle of 45 degrees, the center wavelength was shifted to a lower wavelength side to cause a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

<Example 2> A polyester film having a thickness of 25 μm was used for the base material 2, silicon dioxide was used for the low refractive index layer 7 for the functional layer 3, and titanium dioxide was used for the high refractive index layer 6. The number of layers was five. Total film thickness is 1 μm
And After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The center wavelength of the absorption of visible light perpendicular to the film is 550 nm, and the center wavelength shifts to the lower wavelength side when visible light is incident from an angle of 45 degrees.
A color change occurred. The functional layer 3 on the base material 2 of the seal
Had good adhesion.

<Example 3> A polyester film having a thickness of 25 μm was used for the base material 2, silicon dioxide was used for the low refractive index layer 7, and zirconium dioxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of absorption of visible light perpendicular to the film is 550 nm,
When the light was incident from a degree angle, the center wavelength shifted to the lower wavelength side, and a color change occurred. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

Example 4 A polyester film having a thickness of 25 μm was used for the base material 2, magnesium fluoride was used for the low refractive index layer 7, and zinc sulfide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. Total film thickness is 1
μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption perpendicular to the film was 550 nm. 45 visible light
When the light was incident from a degree angle, the center wavelength shifted to the lower wavelength side, and a color change occurred. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

Example 5 A polyester film having a thickness of 25 μm was used for the base material 2, magnesium fluoride was used for the low refractive index layer 7, and titanium dioxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption perpendicular to the film was 550 nm. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to the lower wavelength side, causing a color change. In addition, the base material 2 of this seal
The adhesion of the functional layer 3 to the substrate was good.

<Example 6> A 25 μm-thick polyester film was used for the base material 2, magnesium fluoride was used for the low refractive index layer 7, and zirconium dioxide was used for the high refractive index layer 6 for the functional layer 5. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption perpendicular to the film was 550 nm.
When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

<Example 7> A polyester film having a thickness of 25 μm was used for the base material 2, magnesium oxide was used for the low refractive index layer 7, and zinc sulfide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. Total film thickness is 1μ
m. After forming the functional layer 3 on the base material 2, the adhesive layer 4
Was provided as a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption perpendicular to the film was 550 nm. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

Example 8 A polyester film having a thickness of 25 μm was used for the base material 2, magnesium oxide was used for the low refractive index layer 7, and titanium dioxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption perpendicular to the film was 550 nm. Visible light
When the light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

Example 9 A polyester film having a thickness of 25 μm was used for the base material 2, magnesium oxide was used for the low refractive index layer 7 for the functional layer 3, and zirconium dioxide was used for the high refractive index layer 6. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption perpendicular to the film was 550 nm.
When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

Example 10 A 25 μm-thick polyester film was used for the substrate 2, magnesium fluoride was used for the low refractive index layer 7, and titanium dioxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2,
A colored layer 9 and an adhesive layer 4 were further provided thereon to form a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. FIG. 5 shows the visible spectrum of this seal.
The center wavelength of visible light absorption parallel to the film is 550 nm
Met. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

Example 11 A polyester film having a thickness of 25 μm was used for the base material 2, calcium fluoride was used for the low refractive index layer 7, and titanium dioxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption parallel to the film was 550 nm. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. In addition, the base material 2 of this seal
The adhesion of the functional layer 3 to the substrate was good.

Example 12 A polyester film having a thickness of 25 μm was used for the base material 2, calcium fluoride was used for the low refractive index layer 7, and tantalum oxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption parallel to the film was 550 nm. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. In addition, the base material 2 of this seal
The adhesion of the functional layer 3 to the substrate was good.

Example 13 A polyester film having a thickness of 25 μm was used for the base material 2, calcium fluoride was used for the low refractive index layer 7, and zinc oxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. Total film thickness is 1
μm. After forming the functional layer 3 on the base material 2, a colored layer 9 and an adhesive layer 4 were provided thereon to form a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example.
The center wavelength of visible light absorption parallel to the film is 550 nm
Met. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

Example 14 A polyester film having a thickness of 25 μm was used for the base material 2, cerium fluoride was used for the low refractive index layer 7 and indium oxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption parallel to the film was 550 nm. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. In addition, the base material 2 of this seal
The adhesion of the functional layer 3 to the substrate was good.

Example 15 A polyester film having a thickness of 25 μm was used for the base material 2, cerium fluoride was used for the low refractive index layer 7, and zirconium dioxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption parallel to the film was 550 nm.
When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

Example 16 A 25 μm-thick polyester film was used for the base material 2, cerium fluoride was used for the low-refractive-index layer 7, and cerium dioxide was used for the high-refractive-index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption parallel to the film was 550 nm. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. In addition, the base material 2 of this seal
The adhesion of the functional layer 3 to the substrate was good.

Example 17 A polyester film having a thickness of 25 μm was used for the base material 2, aluminum fluoride was used for the low refractive index layer 7, and tantalum oxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2,
An adhesive layer 4 was provided to form a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption parallel to the film was 550 nm. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

Example 18 A 25 μm-thick polyester film was used for the base material 2, aluminum fluoride was used for the low refractive index layer 7, and zinc oxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption parallel to the film was 550 nm. Visible light
When the light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

<Example 19> A polyester film having a thickness of 25 μm was used for the base material 2, aluminum fluoride was used for the low refractive index layer 7, and indium oxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption parallel to the film was 550 nm.
When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

<Example 20> A polyester film having a thickness of 25 μm was used for the substrate 2, aluminum oxide was used for the low refractive index layer 7, and zinc sulfide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. Total film thickness is 1
μm. After forming the functional layer 3 on the base material 2, an adhesive layer 4 was provided to provide a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption parallel to the film was 550 nm. 45 visible light
When the light was incident from a degree angle, the center wavelength shifted to the lower wavelength side, and a color change occurred. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

<Example 21> A 25 μm-thick polyester film was used for the base material 2, aluminum oxide was used for the low refractive index layer 7, and cerium dioxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2,
An adhesive layer 4 was provided to form a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The central wavelength of visible light absorption parallel to the film was 550 nm. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

<Example 22> A polyester film having a thickness of 25 μm was used for the base material 2, aluminum oxide was used for the low refractive index layer 7, and titanium dioxide was used for the high refractive index layer 6 for the functional layer 3. The number of layers was five. The total film thickness was 1 μm. After forming the functional layer 3 on the base material 2, a colored layer 9 and an adhesive layer 4 were provided thereon to form a seal. Table 1 shows the configuration of the seal, the state of the layer, and the evaluation results of this example. The center wavelength of absorption of visible light parallel to the film is 550
nm. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. The adhesion of the functional layer 3 to the base material 2 of the seal was good.

[0057]

[Table 1]

<Comparative Example 1> A polyester film having a thickness of 25 μm was used as a base material, magnesium fluoride was used as a low refractive index layer and titanium dioxide was used as a high refractive index layer as a functional layer. Has three layers. After forming the functional layer on the base material, an adhesive layer was provided to form a seal.

Table 1 shows the structure of the seal, the state of the layer, and the evaluation results of this comparative example. FIG. 6 shows the visible spectrum of this transfer foil. The central wavelength of visible light absorption perpendicular to the film was 550 nm. When visible light was incident at an angle of 45 degrees, the center wavelength shifted to the lower wavelength side, but the color change was not sharp. The adhesion of the functional layer to the base material of this seal was good.

Comparative Example 2 A polyester film having a thickness of 25 μm was used as a base material, magnesium fluoride was used as a low-refractive-index layer, and titanium dioxide was used as a high-refractive-index layer. Has seven layers. Total film thickness is 1 μm
And After forming the functional layer on the base material, an adhesive layer was provided to form a seal. Table 1 shows the structure of the seal, the state of the layer, and the evaluation results of this comparative example. The central wavelength of visible light absorption perpendicular to the film was 550 nm. When visible light was incident from an angle of 45 degrees, the center wavelength shifted to a lower wavelength side, causing a color change. However, due to the large number of layers, the adhesion of the functional layer to the base material of the seal was poor, and the functional layer was cracked by bending.

[0061]

The seal of the present invention is obtained by providing a functional layer on a base material, laminating an adhesive layer on the same side or a different side, and specifying the functional layer as a plurality of ceramic materials having different refractive indexes. The thickness of the functional layer reflects or transmits light in a specific wavelength range when laminated, and the optical path length in the thin film changes because the thickness of the functional layer changes depending on the viewing angle. Alternatively, the color of the reflected light changes. As a result, the colors look different, so that the identification is easy and the forgery prevention property is exhibited.

Further, by forming a colored layer as a lower layer,
The seal can be colored without adversely affecting the change in the color of the transmitted light or the reflected light, so that the seal can be more easily viewed and the type of the color can be selected.

As described above, the anti-counterfeiting effect is extremely high.
This is an excellent effect not found in the conventional forgery prevention seal.

[0064]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a seal of the present invention.

FIG. 2 is a sectional view showing a configuration of a seal according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a configuration of a seal according to another embodiment of the present invention.

FIG. 4 is a graph showing a visible spectrum of a functional layer formed by the seal of the present invention in Example 1.

FIG. 5 is a graph showing a visible spectrum of a functional layer formed by the seal of the present invention in Example 10.

FIG. 6 is a graph showing a visible spectrum of the seal of Comparative Example 1 with respect to the seal of the present invention.

[Explanation of symbols]

 1, 11, 12, 13 ... seal 2 ... base material 3 ... functional layer 4 ... adhesive layer 6 ... high refractive index layer 7 ... low refractive index layer 8 ... protective layer 9 ... coloring layer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Bunshin Noguchi 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Satoshi Kitamura 1-1-5-1 Taito, Taito-ku, Tokyo Toppan Examiner Hideaki Takenouchi in Printing Co., Ltd. (56) References JP-A-5-164918 (JP, A) JP-A-62-143002 (JP, A) JP-A-57-140152 (JP, A) JP-A-3 -218822 (JP, A) JP-A-61-87101 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G09F 3/00-3/20 B32B 7/00, 18/00

Claims (4)

(57) [Claims] 1. A plurality of ceramic materials having a functional layer provided on a base material, an adhesive layer laminated on the same surface side or a different surface side, wherein the functional layer has a high refractive index and a low refractive index and has different refractive indexes. A seal characterized by being laminated. 2. The method according to claim 1, wherein the functional layer is a laminate of ceramic materials having different refractive indexes, and a combination of high refractive index layers and low refractive index layers is alternately arranged. The seal described. 3. The method according to claim 1, wherein the functional layer comprises magnesium fluoride, calcium fluoride, cerium fluoride, aluminum fluoride,
A laminate comprising a combination of any one of silicon dioxide, aluminum oxide, or magnesium oxide and any one of zinc sulfide, zirconium dioxide, titanium dioxide, cerium dioxide, tantalum oxide, zinc oxide, and indium oxide. The seal of claim 1, wherein 4. The seal according to claim 1, wherein the functional layer is a laminate of ceramic materials having different refractive indexes, and a colored layer is provided on a surface on an adhesive layer side.