EP1377461A2 - Method for forgery-proof labeling of items, and forgery-proof label - Google Patents

Abstract

The invention relates to a method for forgery-proof labeling of items, such as credit cards, bank notes and the like, comprising the following steps: (a) applying, to a first layer (1) that reflects electromagnetic waves, an inert second layer (3) that is permeable to electromagnetic waves, said second layer having a predetermined thickness, (b) applying, to said second layer (3), a third layer (4) that is formed by metal clusters, and (c) linking the first layer (1) of the label so produced with the item.

Description

description

Method for counterfeit-proof marking of objects and counterfeit-proof marking

The invention relates to a method for counterfeit-proof marking of objects such as check cards, banknotes, packaging and the like. It also relates to a forgery-proof marking.

In the prior art, it is known to provide holograms thereon to prove the authenticity of check cards or banknotes. Magnetic codes are also attached to magnetic strips or fluorescent markings to prove the authenticity of an object. The known markings are relatively easy to fake.

An optochemical sensor is known from US Pat. No. 5,611,998. In this case, a chemically reactive layer is applied to a metal layer, which changes its volume upon contact with a solution containing a substance to be detected. A layer formed from metallic clusters is applied to the chemically reactive layer. By binding the substance to be detected, the distance between the layer formed from the metallic cluster and the metal layer changes. At the same time, the absorption of light radiated onto the sensor also changes. The presence of the substance to be detected causes the color of the sensor to change. The known sensor is not suitable for counterfeit-proof marking of objects. A color change only occurs when a liquid phase is applied to the sensor. In contact with moisture or liquids it can there is also a reaction that triggers or changes a color signal.

The object of the invention is to provide a method for marking objects and a marking which offer a high level of security against forgery in a simple and inexpensive manner.

This object is solved by the features of claims 1, 2, 15 and 16. Appropriate configurations result from the features of claims 3 to 14 and 17 to 29.

According to the invention, a method for counterfeit-proof marking of objects such as check cards, bank notes and the like. , provided, wherein

a) an inert second layer which is permeable to electromagnetic waves and has a predetermined thickness is applied to an electromagnetic layer which reflects electromagnetic waves,

b) a third layer formed from metallic clusters is applied to the second layer and

c) the first layer of the marking thus produced is connected to the object.

With the above-mentioned features, a forgery-proof, permanently visible marking can be produced in a simple and inexpensive manner.

According to a further aspect of the invention, a method for counterfeit-proof marking of objects such as check cards, banknotes and the like is provided, wherein a) an inert second layer which is permeable to electromagnetic waves and has a predetermined thickness is applied to an electromagnetic layer which reflects electromagnetic waves,

b) the first layer of the marking thus produced is connected to the object and

c) a third layer formed from metallic clusters is applied to a substrate in such a way that it is used for

Visualization of the marking can be arranged at a predetermined distance from the first layer.

The further procedural solution enables invisible marking of an object in a simple and inexpensive manner. The marking is particularly forgery-proof. It can be made visible by bringing it into contact with the substrate coated according to the invention.

In both methods, the second layer is expediently applied in a structured manner. The structuring can be a structure in the area in the manner of a pattern or a drawing. However, it can also be a relief-like structure. In this case, the marking appears in different colors.

According to a further design feature, an inert fourth layer which is permeable to electromagnetic waves is applied to the third layer. The fourth layer primarily serves to protect the covered layers.

The substrate can be made from a material that is permeable to electromagnetic waves, preferably from glass or plastic. First molecules which are affine to the second layer or to the second molecules provided thereon are expediently applied to the third or fourth layer. Polymers, silanes or structurally related compounds can be used as molecules. For example, it is also conceivable to use complementary polynucleotide sequences, such as DNA, as molecules. The function of the first and second molecules essentially consists in adhering the substrate to the marking at a fixed predetermined distance.

The metallic clusters can e.g. made of silver, gold, platinum, aluminum, copper, tin or indium. The second and / or fourth layer can be produced from one of the following materials: metal oxide, metal nitrite, metal carbide, in particular from silicon oxide, carbide, nitrite, tin oxide, nitrite, aluminum oxide, nitrite or polymer, in particular polycarbonate (PC ), Polyethylene (PE), polypropylene (PP), polyurethane (PU), polyimide (PI), polystyrene (PS) or polymethacrylate (PMA). These materials are essentially chemically inert. They are not sensitive to moisture. The function of the second layer essentially consists in permanently providing a predetermined distance from the third layer and / or a predetermined structure.

According to a further embodiment, it is provided that a color forming the marking becomes visible when the distance between the first and third layers is less than 2 μm. The coloring depends on the observation angle and is characteristic. For this purpose, the first layer can be irradiated by means of a device for generating electromagnetic waves, preferably by means of a LASER, fluorescent lamp, light-emitting diode or xenon lamp. The marking can be identified using a device for determining the optical properties of the electromagnetic waves reflected by the first layer. It can be set up with Determination of the optical properties of the absorption, preferably at different observation angles. Such a determination of the optical properties enables a high level of security against forgery.

According to a further design feature, it is provided that the layers are / are at least partially produced using thin-film technology. In particular, vacuum coating technologies and the like come into consideration.

According to a further design feature, it is provided that at least one of the layers is made of a material with an anisotropic refractive index. The second layer is preferably made of a material with an anisotropic refractive index. The material can e.g. are liquid crystal polymers which operate both at different viewing angles, i.e. Angles with respect to the z axis, as well as at different angles of rotation, i.e. Angles in the x-y plane, showing a characteristic color.

According to a further design feature, at least one of the layers can be produced from a material whose optical properties can be changed in a targeted manner after the layer has been applied. The material can e.g. are a photosensitive polymer whose refractive index can be changed by irradiation with a suitable wavelength.

According to the invention, a forgery-proof marking for objects such as check cards, banknotes and the like is also provided, an inert second layer having a predetermined thickness permeable to electromagnetic waves being applied to a first layer connected to the object and reflecting electromagnetic waves, and wherein a third layer formed of metallic clusters on the second layer is applied. - Such a marking is permanently visible; it is very forgery-proof.

According to a further provision of the invention, a tamper-proof marking for objects, such as check cards, bank notes and the like, is provided, an inert second layer having a predetermined thickness permeable to electromagnetic waves and being permeable to electromagnetic waves connected to the object connected to the object is upset. - Such a marking is invisible.

If the surface of the object to be marked is already made of a material reflecting electromagnetic waves, e.g. is made of a metal, the first layer can be formed by the object itself.

A third layer formed from metallic clusters can be applied to a substrate in such a way that it can be arranged at a predetermined distance from the first layer in order to make the marking visible.

Because of the further design features of the forgery-proof marking, reference is made to the preceding explanations of the method.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. Show it:

1 is a schematic cross-sectional view of a first permanently visible marking,

2 shows a schematic cross-sectional view of a second permanently visible marking, 3 shows a schematic cross-sectional view of a first marking, which is not always visible, and of a substrate suitable for visualization,

4 shows a schematic cross-sectional view of a second marking, which is not always visible, and of a substrate suitable for visualization,

FIG. 5. Absorption spectra of a marking according to FIG. 1 under different observation angles and

FIG. 6 shows a quantitative evaluation of the spectra according to FIG. 5 at different wavelengths.

In the case of the markings shown in FIGS. 1 to 4, a first layer which reflects electromagnetic waves is designated by 1. It can be a metal foil, e.g. an aluminum foil, act. However, the first layer 1 can also be a layer formed from clusters, which is applied to a carrier 2. The carrier 2 can be the object to be marked. The clusters are expediently made of gold. Likewise, the first layer 1 shown in FIGS. 1 and 3 can also be the object, provided that its surface is formed from a material reflecting electromagnetic waves.

A chemically inert second layer 3 is applied to the first layer 1. The second layer 3 has a structure. The structure here is in the form of a relief, which is designed, for example, in the manner of a bar code. The thickness of the second layer is preferably between 20 and 1000 nm. It is applied by means of thin-layer technology. Vacuum coating processes are suitable for this. In the marking shown in FIGS. 1 and 2, a third layer 4 made of metallic clusters is applied to the second layer 3. The third layer 4 is in turn overlaid by a fourth layer 5. The fourth layer 5 protects the layers below from damage. The fourth layer 5, like the second layer 3, can be made of a chemically inert and optically transparent material, for example a metal oxide, nitrite, carbide or polymer.

The markings shown in FIGS. 3 and 4 are only visible when they are brought into contact with a substrate 6, on the surface of which the third layer 4 formed from metallic clusters is applied. The third layer 4 can be overlaid with a fifth layer 7 formed from first molecules. The fifth layer 7 is expediently formed from molecules which are affine to the material from which the second layer 3 is made. When the fifth layer 7 comes into contact with the second layer 3, specific adherence thus occurs. It may also be the case that the second layer 3 is covered by a further fifth layer 7. In this case, the fifth layers 7 are each formed from molecules which have an affinity for one another. These can be biopolymers that are complementary to one another. The fifth layer 7 can, however, also be made from other polymers, silanes and / or structurally related compounds.

The substrate 6 is made of a transparent material, e.g. out

Glass or plastic.

The function of the marking is as follows: When light from a light source, such as a LASER, a fluorescent tube or a xenon lamp, is irradiated onto a marking shown in FIGS. 1 and 2, this light is reflected at the first layer 1. An interaction of the reflected light with the third layer 4 formed from the metallic clusters absorbs part of the incident light. The reflected light has a characteristic spectrum. The marking appears in color. The color, which depends on the angle of radiation or observation, serves as proof against forgery of the authenticity of the marking.

In the marking shown in FIGS. 3 and 4, only the optically transparent second layer 3 is applied to the electromagnetically reflecting first layer 1. The second layer 3 can consist of chemically inert materials, such as silicon oxide, carbide, nitrite, tin oxide or nitrite, or aluminum oxide or nitrite. The marking is initially not visible.

When the optically transparent substrate 6 provided with the third layer 4 is applied, there may be an interaction between the light reflected on the first layer 1 and the third layer. In turn, a color effect arises which can be observed through the substrate 6, which is preferably made of glass.

In order to ensure that the predetermined distance between the first 1 and the third layer 4 required for producing the color effect is established, the third

Layer 4 be covered with a fifth layer 7. When the fifth layer 7 comes into contact with the second layer 3, the substrate 6 adheres to the marking. A predetermined distance is established between the third layer 4 and the first layer 1. With regard to the parameters to be observed for generating the interactions, reference is made to US Pat. No. 5,611,998, WO 98/48275 and WO 99/47702, the disclosure content of which is hereby incorporated.

The spectra of a marking according to FIG. 1 shown in FIG. 5 were measured by means of a Perkin Elmer Lambda 25 UV / VIS spectrometer using a reflection insert. It can be seen from FIG. 5 that the longer-wave peak shifts towards shorter wavelengths with increasing observation angle. A fixed peak can also be observed, which is due to the silver clusters.

FIG. 6 shows a quantitative evaluation of the spectra according to FIG. 5 in each case at two different wavelengths. At the wavelengths under consideration, a changed absorption is observed depending on the observation angle. The absorption pattern is characteristic of the authenticity of the label.

LIST OF REFERENCE NUMBERS

1 first layer

2 carriers

3 second layer

4 third layer

5 fourth shift

6 substrate

7 fifth layer

Claims

claims 1. A method for counterfeit-proof marking of objects such as check cards, banknotes, packaging and the like., a) an inert second layer (3) which is permeable to electromagnetic waves and has a predetermined thickness is applied to an electromagnetic layer reflecting first layer, b) a third layer (4) formed from metallic clusters is applied to the second layer (3) and c) the first layer (1) of the marking thus produced is connected to the object. 2. A method for counterfeit-proof marking of objects such as check cards, banknotes, packaging and the like., a) an inert second layer (3) which is permeable to electromagnetic waves and has a predetermined thickness is applied to an electromagnetic layer reflecting first layer, b) the first layer (1) of the marking thus produced is connected to the object and c) a third layer (4) formed from metallic clusters is applied to a substrate (6) in such a way that it can be arranged at a predetermined distance from the first layer (1) to make the marking visible. 3. The method according to any one of the preceding claims, wherein at least one of the layers (3,4,5) is applied in a structured manner. 4. The method according to any one of the preceding claims, wherein an inert fourth layer (5) permeable to electromagnetic waves is applied to the third layer (4). 5. The method according to any one of claims 2 to 4, wherein the substrate (6) is made of a material permeable to electromagnetic waves, preferably made of glass or plastic. 6. The method according to any one of claims 2 to 5, wherein on the third (4) or fourth layer (5) first molecules (7) are applied, which are affine to the second layer (3) or to the second molecules provided thereon. 7. The method according to claim 6, wherein the molecules (7) used are polymers, silanes or structurally related compounds. 8. The method according to any one of the preceding claims, wherein the metallic clusters are made of silver, gold, platinum, aluminum, copper, tin or indium. 9. The method according to any one of the preceding claims, wherein the second (3) and / or fourth layer (5) is / are made from one of the following materials: metal oxide, metal nitrite, metal carbide, in particular from silicon oxide, carbide, nitrite , Tin oxide, nitrite, aluminum oxide, nitrite or polymer, in particular polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyurethane (PU), polyimide (PI), polystyrene (PS) or polymethacrylate (PMA). 10. The method according to any one of the preceding claims, wherein at a distance between the first (1) and the third layer (4) of less than 2 microns a coloring forming the mark is visible. 11. The method according to any one of the preceding claims, wherein the marking is irradiated by means of a device for generating electromagnetic waves, preferably by means of LASER, fluorescent lamp, light-emitting diode or xenon lamp. 12. The method according to any one of the preceding claims, wherein the marking is identified with a device for determining the optical properties of the electromagnetic waves reflected by the first layer (1), preferably at different observation angles. 13. The method according to any one of the preceding claims, wherein the absorption is measured with the device for determining the optical properties. 14. The method according to any one of the preceding claims, wherein the layers (1, 3, 4, 5) is / are at least partially produced by means of thin-film technology. 15. The method according to any one of the preceding claims, wherein at least one of the layers (3, 4, 5) has an anisotropic refractive index. 16. The method according to any one of the preceding claims, wherein at least one of the layers is made of a material whose optical properties can be changed after the layer has been applied. 17. Counterfeit-proof marking for objects, such as check cards, bank notes and the like, an inert second layer (3) which is permeable to electromagnetic waves and having a predetermined thickness being applied to a first layer (1) connected to the object and reflecting electromagnetic waves, and wherein a third layer (4) formed from metallic clusters is applied to the second layer (3). 18. Counterfeit-proof marking for objects such as Check cards, banknotes and the like, wherein an inert second layer (3), which is permeable to electromagnetic waves and has a predetermined thickness, is applied to a first layer (1) which reflects electromagnetic waves and is connected to the object. 19. A counterfeit-proof marking according to claim 18, wherein a third layer (4) formed from metallic clusters is applied to a substrate (6) in such a way that it can be arranged at a predetermined distance from the first layer (1) to make the marking visible. 20. Counterfeit-proof marking according to one of claims 17 to 19, wherein the at least one of the layers (1, 3, 4,5) has a structure. 21. Counterfeit-proof marking according to one of claims 17 to 20, wherein an inert fourth layer (5) covering the third layer (4) and permeable to electromagnetic waves is provided. 22. Counterfeit-proof marking according to one of claims 18 to 21, wherein the substrate (6) is made of a material permeable to electromagnetic waves, preferably of glass or plastic. 23. Counterfeit-proof marking according to one of claims 18 to 22, wherein on the third (4) or fourth layer (5) first molecules (7) are applied which are affine to the second layer (3) or to the second molecules provided thereon. 24. A counterfeit-proof marking according to claim 23, wherein the molecules (7) are made from polymers, silanes or structurally related compounds. 25. Counterfeit-proof marking according to one of claims 17 to 24, wherein the metallic clusters are formed from silver, gold, platinum, aluminum, copper, tin or indium. 26. Counterfeit-proof marking according to one of claims 17 to 25, wherein the second (3) and / or fourth layer (5) is / are made from one of the following materials: metal oxide, metal nitrite, metal carbide, in particular from silicon oxide, carbide, nitrite, tin oxide, nitrite, aluminum oxide, nitrite or polymer, in particular polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyurethane (PU), polyimide (PI), polystyrene (PS) or polymethacrylate (PMA). 27. A counterfeit-proof marking according to one of claims 17 to 26, wherein a clearly identifiable color is recognizable at a distance between the first (1) and the third layer (4) of less than 2 μm. 28. Counterfeit-proof marking according to one of claims 17 to 27, wherein a device for generating electromagnetic waves, preferably a LASER, a fluorescent lamp, light-emitting diode or a xenon lamp, is provided for irradiating the marking. 29. A counterfeit-proof marking according to one of claims 17 to 28, wherein a device for identifying the marking device for determining the optical properties of the electromagnetic waves reflected by the first layer (1) is provided. 30. Counterfeit-proof marking according to one of claims 17 to 29, wherein the absorption, preferably at different observation angles, can be measured with the device for determining the optical properties. 31. Counterfeit-proof marking according to one of claims 17 to 30, wherein the layers (1, 3, 4, 5) are / are produced by means of thin-film technology.