JPH11235900A - Forgery preventing decorative medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forgery preventing decorative medium representing an image by partly changing an optical film thickness of an optically functional layer, partly changing a luminous reflectance of the functional layer, and generating presence or absence (difference in luminous reflectance) of a sense of glittering. SOLUTION: The forgery preventing decorative medium of a constitution having an optically functional layer on a support expresses an image by a difference of luminous reflectances by partly changing an optical film thickness of the functional layer 24 and partly changing a luminous reflectance of the layer 24. In this case, the reflectance of a low luminous reflectance area 14L of the functional layer is set to 10.0 or less. And, the reflectance of a high reflectance area 14H is set to 15.0 or more. And, a line image is expressed by a contrast of the area 14L and the area 14H.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-counterfeiting medium in the form of a transfer foil which is transferred to, for example, credit cards, securities, certificates, etc., an anti-counterfeiting medium in the form of a seal attached to an article, or molded into the article itself Media such as anti-counterfeiting media or highly decorative media such as wrapping paper and commercial prints, especially OVDs such as holograms and gratings
(Optical Variable Device).

[0002]

2. Description of the Related Art Conventionally, as means for preventing forgery, it is difficult to imitate the medium itself, and it is easy to find traces of fraudulent acts such as forgery and falsification. Methods are used to ensure identification. For example, securities, such as banknotes, are themselves subjected to fine processing or coloring with a color that is difficult to imitate, or the material is special, illegal use of the structure or printing technology, or illegal use by a copying machine The forgery is prevented by making it difficult to make a forgery due to a simple copy.
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, the processing technology has been miniaturized to make copying and forgery more difficult.

In addition, a method for preventing counterfeiting by sticking and bonding a special optical medium having a metallic luster to an article in the form of a transfer foil or a seal, which is difficult to copy and counterfeit with a copying machine or printing technology, has also been used. ing. For example, there is a method of forming a hologram image or a grating image on a card by bonding an OVD transfer foil to the card by thermal transfer, such as a credit card.

Holograms and gratings have an interference function that causes a unique color shift (color change of reflected light) according to the viewing angle, and the colors that can be seen differ depending on the observation position. The anti-counterfeiting medium has a special anti-counterfeiting effect against counterfeiting using a color copying machine at the same time as it can be determined whether or not it is.

On the other hand, holograms and gratings have an optical effect (glitter), 3D three-dimensional representation, and the like, and can be said to be extremely excellent as a decorative medium as a decorative medium.

[0006]

SUMMARY OF THE INVENTION The present invention has been devised in order to make it difficult to forge these conventional techniques, and it is an object of the present invention to make it difficult to imitate the medium itself. Another object of the present invention is to provide a novel anti-counterfeiting medium that can easily detect traces of fraudulent acts such as counterfeiting and tampering, and can surely distinguish a genuine article from a counterfeit article.

The present invention also relates to the conventional OVD (herein, referred to as OVD, a technique for optically expressing an image such as the hologram image and the grating image).
D, hereinafter referred to as OVD) to provide a new decorative effect, and to provide a new decorative medium that expresses an image by the presence or absence of glitter. It is in.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for partially changing the luminous reflectance of an optical function layer by partially changing the optical thickness of the optical function layer. The present invention provides a forgery-preventive decorative medium that expresses an image by causing the presence or absence of glitter (difference in luminous reflectance).

That is, the invention of claim 1 is a forgery-prevention decorative medium having a structure including an optical functional layer on a support, wherein the optical thickness of the optical functional layer is partially changed to achieve an optical characteristic. A forgery-preventive decorative medium characterized by partially changing the luminous reflectance of the functional layer and expressing an image by a difference in luminous reflectance.

[0010] Further, according to the invention of claim 2, O 2 is provided on the support.
A forgery-preventing decorative medium having a configuration in which a VD layer and an optical function layer are at least laminated, and the luminous reflectance of the optical function layer is partially changed by partially changing the optical film thickness of the optical function layer. A forgery-prevention decorative medium characterized by changing the luminous reflectance to express an image.

Further, the invention according to claim 3 is the anti-counterfeit decorative medium according to claim 1 or 2, wherein the luminous reflectance of the low luminous reflectance area of the optical function layer is 10.0 or less, And the luminous reflectance in the high luminous reflectance area is 15.0.
As described above, the line drawing is expressed by the contrast between the low luminous reflectance area and the high luminous reflectance area.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The anti-counterfeit decorative medium of the present invention is an anti-counterfeit decorative medium comprising a support and an optical functional layer, wherein the optical thickness of the optical functional layer is partially changed. Thus, the luminous reflectance of the optical functional layer is partially changed, and an image is expressed by a difference in the luminous reflectance. A line drawing is represented by contrast between a low luminous reflectance area and a high luminous reflectance area, with a luminous reflectance of 10.0 or less and a luminous reflectance of a high luminous reflectance area of 15.0 or more. It is.

An embodiment of the present invention will be described in detail with reference to the drawings. <Embodiment 1> Hereinafter, in Embodiment 1, a forgery prevention decorative medium in the form of a transfer foil will be described with reference to the drawings. FIG. 1 is a plan view showing a forgery-preventing decorative medium according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a laminated structure of the forgery-preventing decorative medium according to one embodiment.

Forgery-preventing decorative medium 11 in Embodiment 1
Is a substrate 2 as a support, as shown in FIGS.
1 has a structure in which a peeling protection layer 22, an optical function layer 24, and an adhesive layer 25 are sequentially laminated.

The substrate 21 is a transparent polyethylene terephthalate film having a thickness of 25 μm. As a substrate,
In addition, synthetic resin such as polyvinyl chloride, polyester, polycarbonate, polymethyl methacrylate, polystyrene, etc., natural resin, paper, synthetic paper, etc. are used alone, or composites selected from above are used. It is possible.

Further, the peeling protection layer 22 comprises an optical function layer 24
The composition having the following composition ratio was prepared by a gravure printing method at a drying temperature of 11%.
It is formed at 0 ° C. and 0.8 μm in thickness.

<Composition of the release protective layer> Acrylic resin: 30 parts Polyester resin: 5 parts Toluene: 40 parts Methyl ethyl ketone: 40 parts Methyl isobutyl ketone: 20 parts

The protective layer 22 may be made of thermoplastic acrylic resin, chlorinated rubber resin, vinyl chloride-vinyl acetate copolymer resin, cellulose resin, chlorinated polypropylene resin or oil silicone, fatty acid amide, zinc stearate, etc. Can be used.
Alternatively, an inorganic substance may be used.

The optical function layer 24 is a layer that reflects light rays and has an interference function of changing the reflectance at each wavelength in accordance with the optical film thickness and configuration, and expresses (forms) an image. ). In the first embodiment,
Low luminous reflectance area 14L and high luminous reflectance area 14H
Anti-counterfeit decorative medium 1 in which two types of areas are alternately arranged
The optical functional layers 2 each having the following configuration
4 is formed by a vacuum evaporation method and a sputtering method.

<Optical functional layer in low luminous reflectance area 14L> High refractive index ceramic film: TiO ₂ (n = 2.0) 130 nm

<Optical Function Layer of High Luminous Reflectance Area 14H> High refractive index ceramic film: TiO ₂ (n = 2.0) 65 nm

In the first embodiment, the optical function layer 24 is made of a high-refractive-index ceramic film. Laminated structure of film / metal film, high refractive index ceramic film / low refractive index ceramic film / high refractive index ceramic film, metal thin film / high refractive index ceramic film / low refractive index ceramic film / high refractive index ceramic film / metal film, etc. It is possible to use any structure as long as it has a layer structure having an interference function.

As the ceramic used for the high refractive index ceramic film of the optical function layer 24, zinc sulfide, zirconium dioxide, indium oxide, tin oxide, tantalum oxide, cerium oxide, zinc oxide and the like can be used. ing.

As a method of forming the high refractive index ceramic film, any film forming method can be used as long as the film thickness can be controlled. Above all, a dry method is superior for forming a thin film, and a physical vapor deposition method such as an ordinary vacuum vapor deposition method, sputtering or a chemical vapor deposition method such as a CVD method can be used for this purpose.

Although not shown in the first embodiment, a metal thin film and a metal film usable for the optical function layer 24 include:
Metal materials such as aluminum, iron, titanium, gold, silver, and copper can be used. In addition, as a method of forming the metal thin film and the metal film, a thin film forming means such as an evaporation method and a sputtering method can be used, and can be arbitrarily selected according to a material forming the metal thin film and the metal film.

Similarly, low refractive index ceramic films usable for the optical function layer 24 include magnesium fluoride, calcium fluoride, aluminum fluoride, cerium fluoride, and the like.
Silicon dioxide, aluminum oxide, magnesium oxide and the like can be used. As a method of forming the low refractive index ceramic film, a method similar to the method of forming the high refractive index ceramic film can be used.

The adhesive layer 25 is formed by a gravure printing method at a drying temperature of 110 ° C. and a thickness of 1.0 μm.

<Composition of Adhesive Layer> Vinyl chloride-vinyl acetate copolymer: 30 parts Polyester resin: 20 parts Methyl ethyl ketone: 50 parts Toluene: 50 parts

In addition, as the adhesive layer 25, any other material may be used as long as it does not alter or affect the optical function layer 24. For example, an acrylic adhesive, polyester polyamide or the like can be used. However, the present invention is not limited to these.

The two types of optical functional layers 24 having the above-described structure (low luminous reflectance area 14L and high luminous reflectance area 14H).
Can change the luminous reflectance by changing its optical film thickness. The luminous reflectance and the optical film thickness will be described below. <Definition of luminous reflectance Y> The luminous reflectance Y in the embodiment of the present invention is a value measured based on CIE1931 and corresponds to an observation field of 2 degrees. Actually, the luminous reflectance Y is obtained by the following equation (Equation 1). The illumination light was measured using standard illumination C.

[0031]

(Equation 1)

<Definition of Optical Film Thickness> The optical film thickness nd (nm) in the embodiment of the present invention is obtained by multiplying the refractive index n of the object by the actual film thickness d (nm) of the object. Due to the change, the luminous reflectance Y changes due to light interference. That is, in the present embodiment, only the method of changing the actual film thickness d is described, but the present invention can be achieved by the method of changing the refractive index n.

As a result of experiments conducted by the inventors, the relationship between the optical film thickness of TiO ₂ , which is the high refractive index ceramic film used in Example 1, and the luminous reflectance is shown in FIG. A luminous reflectance of 13.0 was found as a boundary value at which the user felt bright / dark.

According to the above experimental results, the low luminous reflectance area 1
4L, the optical film thickness of TiO ₂ , which is a high refractive index ceramic film, is set to 210 nm or more and 300 nm or less so that the luminous reflectance is 13.0 or less, and the high luminous reflectance area 14H is luminous reflectance of 13.0 or more. The optical film thickness of TiO ₂ , which is a high refractive index ceramic film, is set to 100 nm or more and 210 nm so that
The optical function layer 24 was formed as follows.

When a line image is used for an image displayed by generating the presence or absence of glitter in the optical function layer 24, the luminous reflectance of the low luminous reflectance area 14L is increased in order to increase the contrast of the image. Is preferably 10.0 or less, and the luminous reflectance of the high luminous reflectance area 14H is preferably 15.0 or more. In the first embodiment, the optical thickness is 260 nm, and the luminous reflectance of the high luminous reflectance area 14H is 27.0 so that the luminous reflectance of the low luminous reflectance area 14L is 8.0. Thus, the optical functional layer 24 was formed with an optical film thickness of 130 nm.

As a method of alternately arranging the two types of areas of the low-reflectance area 14L and the high-reflectance area 14H, there are physical vapor deposition methods such as ordinary vacuum evaporation and sputtering, and CVD. The optical function layer 24 of the anti-counterfeit decoration medium 11 was produced by using a partial vapor deposition method of partially vapor-depositing using a mask when performing a chemical vapor deposition method.

Specifically, first, vapor deposition is performed using a lattice-shaped mask 41 as shown in FIG. 4 so that the optical film thickness becomes 130 nm. As a result, a high-refractive-index ceramic film having an optical film thickness of 130 nm is formed in the mask opening portion 42, and no high-refractive-index ceramic film is formed in the mask shielding portion 43.

Next, the mask 41 is removed, and vapor deposition is performed again so that the optical film thickness becomes 130 nm. Thus, the optical film thickness 1 formed by the mask opening 42
The part laminated on the high refractive index ceramic film of 30 nm
The low-reflectance area 14L having an optical film thickness of 260 nm is formed. A portion stacked by the mask shielding portion 43 on a portion where the high-refractive-index ceramic film is not formed has an optical film thickness of 130 nm.
Is a high reflectance area 14H.

The anti-counterfeit decorative medium 11 manufactured by the above method can be transferred to various media by a conventional heat transfer method (hot stamp, roll transfer, lamination, etc.) and used.

As described above, according to the first embodiment of the present invention, a stripe-shaped image can be expressed by the presence or absence of glitter (difference in luminous reflectance), and a new decoration with a high decorative effect can be obtained. The medium could be provided. In addition, this makes it difficult to imitate the medium itself, and it is easy to find traces of fraudulent acts such as forgery and falsification, and a new anti-counterfeiting medium that can reliably discriminate between genuine and fake. Could be provided.

<Embodiment 2> In Embodiment 2 of the present invention, the OV
The D label type forgery prevention decorative medium will be described with reference to the drawings. FIG. 5 is a plan view showing a forgery-preventing decorative medium according to another embodiment of the present invention, and FIG. 6 is a cross-sectional view showing one laminated structure of the forgery-preventing decorative medium.

In the forgery-preventing decorative medium 51, an OVD layer 63 is formed on a base material 61 as a support, and thereafter, an optical function layer 64 and an adhesive layer 65 are sequentially formed.

The substrate 61 is a transparent polyethylene terephthalate film having a thickness of 50 μm. As this substrate, the substrate described in Example 1 can be used.

The OVD layer 63 has a structure in which a relief type OVD 63a is formed on the surface opposite to the base material 61.

The relief type OVD 63a can be formed by a known method such as heating and pressing a nickel press plate having a fine uneven pattern constituting the relief type OVD on the OVD layer 63.

OVD image 5 by this relief type OVD
No. 2 used a rainbow hologram image which is a conventional relief hologram.

The OVD layer 63 has good embossability,
Press unevenness hardly occurs, and a bright reproduced image is obtained.
1 and a resin having good adhesion to the optical function layer 64, and a composition having the following compounding ratio is formed by gravure printing at a drying temperature of 110 ° C. and a thickness of 0.5 μm.

<Composition of OVD layer> Vinyl chloride-vinyl acetate copolymer: 25 parts Urethane resin: 10 parts Methyl ethyl ketone: 70 parts Toluene: 30 parts

The relief OVD forming surface is formed by press-molding the OVD layer 63 having such a composition at a plate surface temperature of 165 ° C.

As the OVD layer 63, other thermoplastic resins such as polycarbonate resin, polystyrene resin and polyvinyl chloride resin, unsaturated polyester resin, melamine resin, epoxy resin, urethane (meth) acrylate, polyester (meth) acrylate , Epoxy (meth) acrylate, polyol (meth) acrylate,
Thermosetting resins such as melamine (meth) acrylate and triazine (meth) acrylate or mixtures thereof, as well as thermoformable materials having radically polymerizable unsaturated groups can be used. Any material can be used as long as it has a stability capable of forming a diffraction structure.

The optical function layer 64 is a layer that reflects light rays and has an interference function of changing the reflectance at each wavelength according to its optical film thickness and configuration. Layer. In the second embodiment, the forgery-preventing decorative medium 51 in which the luminous reflectance is periodically changed is used.
It is formed by a vacuum evaporation method and a sputtering method.

Optical function layer 64 at minimum luminous reflectance portion (maximum film thickness) High refractive index ceramic film: TiO ₂ (n = 2.0) 120 nm Optical functional layer 64 at minimum luminous reflectance portion (minimum film thickness) ) High refractive index ceramic film: TiO ₂ (n = 2.0) 90 nm

As a method of periodically changing the luminous reflectance, a mask is used when performing a physical vapor deposition method such as an ordinary vacuum vapor deposition method or sputtering or a chemical vapor deposition method such as a CVD method. The optical function layer 64 of the anti-counterfeit decoration medium 51 is formed by using a partial evaporation method in which the evaporation density is partially changed by using
Was prepared.

Specifically, first, as shown in FIG. 7, a lattice-like mask 41 is provided between the evaporation source 72 and the film 73 to be evaporated, and evaporation is performed so that the optical film thickness becomes 240 nm. As a result, the deposit is diffracted from the edge of the mask opening 42, and the maximum optical film thickness is 240 nm immediately below the opening.
Is formed, and the mask shielding portion 43 is formed.
The optical film thickness decreases as approaching directly below, and a high refractive index ceramic film having a minimum optical film thickness of 180 nm is formed immediately below the mask shielding portion 43.

The adhesive layer 65 is formed of a composition having the following compounding ratio at a drying temperature of 110 ° C. and a thickness of 20 μm by gravure printing.

<Composition of Adhesive Layer> Acrylic adhesive 30 parts Methyl ethyl ketone 35 parts Toluene 35 parts

The material for forming the adhesive layer 65 is, for example, butyl rubber, natural rubber, silicon, or the like.
Adhesive components such as polyisobutyl, alkyl methacrylate, vinyl ester, acrylonitrile, styrene,
Aggregation components such as vinyl monomers, and modifiers such as unsaturated carboxylic acids, hydroxyl-containing monomers, and acrylonitrile, and additives such as polymerization initiators, plasticizers, curing agents, curing accelerators, and antioxidants Can be applied as needed, but is not limited thereto.

The anti-counterfeit decorative medium 11 manufactured by the above method can be transferred to various media by a conventional heat transfer method (hot stamp, roll transfer, lamination, etc.) and used.

[0059]

According to the present invention having the above-described structure, an image in which the presence or absence of glitter (a difference in luminous reflectance) changes periodically can be expressed by being superimposed on an OVD image, and a high decorative effect can be obtained. A new OVD decoration medium could be provided.
In addition, this makes it difficult to imitate the medium itself, and it is easy to find evidence of fraudulent acts such as forgery and falsification. The medium could be provided.

[Brief description of the drawings]

FIG. 1 is a plan view showing a forgery-preventing decorative medium according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a laminated structure in an embodiment of the anti-counterfeit decoration medium.

FIG. 3 is a correlation diagram showing the relationship between the optical film thickness of TiO ₂ and the luminous reflectance according to the anti-counterfeit decorative medium of the present invention.

FIG. 4 is a plan view showing one embodiment of a mask according to the forgery-preventing decorative medium of the present invention.

FIG. 5 is a plan view showing a forgery-preventing decorative medium according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a laminated structure of the forgery-preventing decorative medium.

7A and 7B are schematic views illustrating an example of a method for forming an optical functional layer according to the forgery-preventing decorative medium of the present invention, wherein FIG. 7A is a side view and FIG. 7B is a bottom view.

[Explanation of symbols]

 11, 51: anti-counterfeit decoration medium 14L: low luminous reflectance area 14H: high luminous reflectance area 21, 61: base material 22: release protective layer 24, 64: optical functional layer 25: adhesive layer 41: mask 42 ... Mask opening 43 ... Mask shielding part 52 ... OVD image 63 ... OVD layer 65 ... Adhesive layer 71 ... Evaporation device 72 ... Evaporation source 73 ... Evaporation film

Claims (3)

[Claims] An anti-counterfeit decorative medium comprising an optical functional layer on a support, wherein the optical functional layer has a luminous reflectance by partially changing an optical thickness of the optical functional layer. Wherein the image is expressed by a difference in luminous reflectance. 2. A forgery-preventing decorative medium having a structure in which an OVD layer and an optical functional layer are laminated at least on a support, wherein the optical thickness of the optical functional layer is partially changed.
A forgery-preventive decorative medium characterized by partially changing the luminous reflectance of an optical functional layer and expressing an image by a difference in luminous reflectance. 3. The low luminous reflectance in the low luminous reflectance area of the optical function layer is set to 10.0 or less and the luminous reflectance in the high luminous reflectance area is set to 15.0 or more. 3. The forgery-prevention decorative medium according to claim 1, wherein a line drawing is represented by a contrast between the reflectance area and the high luminous reflectance area.