EP3511176B1 - Security element with an optically variable structure in a recess - Google Patents

Description

The invention relates to a security element with an optically variable structure which has an embossed structure and a coating, the embossed structure and the coating being combined in such a way that at least parts of the coating are completely visible when viewed perpendicularly, but are covered when viewed obliquely, so that when viewed at an angle Changing the viewing direction different information becomes visible. The invention also relates to an embossing tool for producing such a security element.

Out EP 2 886 356 A2 a method for producing a document of value, in particular a bank note, is known, in which a flowable, UV-crosslinkable, effect pigments-containing color layer is applied to a document of value substrate by means of a first screen printing unit. The ink layer is incompletely crosslinked by means of a first UV drying device in order to increase the viscosity of the ink layer and make it embossable. The incompletely crosslinked color layer is then brought into contact with an embossing tool within a second screen printing unit in order to provide the color layer with a macroscopic embossed structure, the depressions of the macroscopic embossed structure having a depth in a range from 13 μm to 30 μm. In addition, the color layer is provided with a fine embossed structure superimposed on the macroscopic embossed structure, the depressions of the fine embossed structure having a depth in a range from 0.1 µm to 10 µm. Finally, the color layer is completely crosslinked by means of a second UV drying device.

Out WO 2009/013000 A2 a security element with an optically variable structure is known which has an embossed structure. When the security element is tilted about an axis and therefore viewed alternately from a first and second viewing angle range, a tilting effect is created which shows different colors or brightnesses from the two different viewing angles or at different angles of incidence of light. The optically variable structure has at least one second embossed structure, which is arranged within the first embossed structure and generates a second tilting effect in addition to the first tilting effect. The second tilting effect occurs either within the first or second viewing angle range or at the transition from the first to the second or from the second to the first viewing angle range.

Out WO 2013/045055 A1 a security element with an optically variable structure is known which has a multiplicity of first embossed structures, each of the first embossed structures consisting of at least two flanks which converge at least at a certain angle. In at least a first partial area of the optically variable structure, at least one flank of the first embossed structures each has at least one additional embossed structure which is placed on the flank of the first embossed structures or inserted into the flank of the first embossed structures. The geometry of the at least one additional embossed structure is implemented at least almost inversely to the geometry of that flank of the first embossed structure on which the at least one additional embossed structure is placed or inserted.

Out EP 3124 284 A1 a security element for an object of value from a substrate is known, in particular a bank note, a label for product security or an outer packaging, a tactilely detectable structure being embossed into the substrate. The tactilely detectable structure consists of a first embossed structure and a second embossed structure, wherein the second embossed structure is arranged within the first embossed structure. The first embossed structure forms a base for the second embossed structure on which the second embossed structure is arranged. The second embossed structure is designed to be significantly higher than the first embossed structure, so that the tactility of the tactilely detectable structure is essentially created by the second embossed structure. The sole purpose of the base is to prevent possible substrate damage that could result from the embossing of the second embossed structures.

Out WO 2013/020687 A1 a relief structure is known for displaying different images in different viewing directions, the relief structure having a plurality of grooves. Each groove has a first and second side wall for displaying a first and second image in a first and second viewing direction and additionally a bottom area for displaying a third image in a third viewing direction. The first, second and third images are only visible from the first, second and third viewing directions, while superimposed mixtures of two or three images are visible from other viewing angles. In addition, the bottom area and the first and second side walls each have depressions.

The invention is therefore based on the object of developing a generic security element in such a way that the protection against counterfeiting is further increased.

This object is achieved by the features of the independent claims. Developments of the invention are the subject of the dependent claims.

According to the invention, the embossed structure as defined in claim 1 consists of a first embossed element with an embossed depth of more than 30 µm and second embossed elements with an embossed depth of more than 10 µm, the second embossed elements being arranged within the first embossed element and superimposing it, the security element consists of a substrate made of paper or cardboard and the embossed structure is embossed into the substrate. In particular, the embossing displaces the material of the substrate and thus creates a permanent deformation of the substrate.

The corresponding embossing tool has, as defined in claim 4, a first elevation or depression for producing a first embossing element with a depth of more than 30 µm, with second elevations or depressions having a depth of more than 10 µm being arranged within the first elevation or depression, so that the first elevation or depression and the second elevations or depressions overlap.

The depth of the respective elevation or depression in the embossing tool is known to be slightly greater than that of the corresponding embossing elements in the substrate of the security element that were produced with this embossing tool. This difference between the depth / height of the structures in the embossing tool and the height / depth of the embossing structures in the substrate is due to the fact that the substrate cannot be pressed completely into the depressions or on the elevations of the embossing tool during the embossing process.

According to a preferred embodiment it is provided that the first embossing element consists of a channel-shaped or hipped roof-shaped or dome-shaped depression or elevation. Correspondingly, the first elevation or depression of the embossing tool is designed in the shape of a channel or hipped roof or dome shape. Dome-shaped means im For the purposes of this invention, that the depression or elevation is at least approximately in the form of a spherical or elliptical cap or shell. Instead of spheres or ellipses, similar dome-shaped or elongated shapes are also possible, the cross section of which is at least approximately in the form of a segment of a circle or ellipse. In addition, it is particularly expedient if the indentations or elevations of the embossing tool merge softly at their edge into the surrounding surface of the embossing tool in order to avoid any substrate damage during an embossing process. The steepness of the flanks also influences the tear behavior of the substrate.

The first embossing element or the first elevation or depression of the embossing tool preferably has a depth of 30 μm to 1000 μm, particularly preferably 30 μm to 400 μm and very particularly preferably 50 μm to 200 μm.

The first embossing element or the first elevation or depression of the embossing tool preferably has a diameter of 30 μm to 1500 μm, particularly preferably 100 μm to 700 μm and very particularly preferably 120 μm to 500 μm.

According to the invention, the first embossing element or the first elevation or depression of the embossing tool is at least three times larger in both lateral and vertical dimensions than the second embossing elements or second elevations or depressions of the embossing tool.

According to a further advantageous embodiment, the distance between two adjacent second embossing elements or second elevations or depressions of the embossing tool is 0 μm to 100 μm, preferably 0 μm to 50 μm and particularly preferably 0 μm to 20 μm.

According to a further advantageous embodiment, the outer contour of the second embossing elements or second elevations or depressions of the embossing tool is designed triangular, square, pentagonal, hexagonal or honeycomb or polygonal.

The dimensions of the first embossing element or the first elevation or depression of the embossing tool depend on the material thickness and the embossing material property of the substrate to be embossed.

The first elevation or depression and the second elevations or depressions are preferably generated with a laser in order to be able to generate a higher aspect or depth or height-to-width ratio, a greater variety of geometries and steeper flanks.

According to a further advantageous embodiment, the coating of the security element is a metallic or metallic-looking surface that is applied to the substrate, for example, by screen printing, a silver patch or a film or a laminated material that is applied to the substrate. Furthermore, the material of the substrate itself can already have a metallic or reflective design.

An optically variable element in the context of this invention is an element whose visual appearance changes when the element is tilted or rotated. For example, when the optically variable element is tilted or rotated, its color changes, a bar of one appears to move Side of the element to another side, different characters are displayed when tilting or rotating, or a so-called pumping effect results in the form of an enlarging or reducing outline of a picture motif.

The substrate particularly preferably consists of paper made of cotton fibers, as used for example for banknotes, or of other natural fibers or of synthetic fibers or a mixture of natural and synthetic fibers, or of at least one plastic film. Furthermore, the substrate preferably consists of a combination of at least two different substrates arranged one above the other and connected to one another, a so-called hybrid. Here, the substrate consists for example of a combination of plastic film-paper-plastic film, i.e. a substrate made of paper is covered on either of its two sides by a plastic film, or of a combination paper-plastic film-paper, i.e. a substrate made of a plastic film is covered on each of its two sides by paper.

Information on the weight of the substrate used for banknotes is given, for example, in the document DE 102 43 653 A9 specified. The font DE 102 43 653 A9 states in particular that the paper layer usually has a weight of 50 g / m ² to 100 g / m ² , preferably 80 g / m ² to 90 g / m ² . Of course, any other suitable weight can be used depending on the application.

The substrate particularly preferably consists of cardboard or paper with a weight per unit area of 120 g / m ² or more.

Documents of value for which such a substrate or security paper can be used are in particular banknotes, shares, bonds, certificates, vouchers, checks, high-quality admission tickets, but also other papers that are at risk of forgery, such as passports and other identification documents, as well as cards such as credit cards. or debit cards, the card body of which has at least one layer of security paper, and also product security elements such as labels, seals, packaging, folding boxes, package inserts, blisters, aluminum foils and the like.

The simplified designation of value document includes all of the above-mentioned materials, documents and product security means.

The terms "front" or "back" of the substrate or document of value or of the embossing tool are relative terms, which can also be referred to as "one" and "the opposite" side and which cover the majority of the total surface of the substrate or document of value or of the embossing tool form. These terms expressly do not include the side surfaces of a substrate or document of value or of the embossing tool, which are at a thickness of a substrate or document of value. In the case of card bodies with a thickness of only about one millimeter or with banknotes with a thickness of only fractions of a millimeter, the side surfaces are negligibly small and are usually not provided with security elements or coatings.

Information within the meaning of this invention is a visually perceptible representation designed in the form of a pattern. This can, for example, form an alphanumeric string of digits and / or letters, a graphic image, an image, a text or other characters. The information particularly preferably consists of positive and / or negative motifs. In the case of a positive motif, a motif element itself appears the substrate is applied, whereas in the case of a negative motif, the area surrounding the motif element is applied to the substrate. A positive motif is, for example, a letter printed in dark color on the light substrate. A negative motif is, for example, an area applied to the light-colored substrate in a dark color, which has an unprinted area in the form of a letter within the area.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations without departing from the scope of the present invention, insofar as this is covered by the scope of protection of the claims.

The advantages of the invention are explained using the following exemplary embodiments and the supplementary figures. The exemplary embodiments represent preferred embodiments to which, however, the invention is not intended to be restricted in any way. Furthermore, the representations in the figures are highly schematic for better understanding and do not reflect the real conditions. In particular, the proportions shown in the figures do not correspond to the conditions present in reality and serve exclusively to improve the clarity.

The embodiments described in the following examples are reduced to the essential core information for better understanding. In the practical implementation, much more complex patterns or images in single or multi-color printing can be used as a coating. The same applies to the embossed structures. The information presented in the following examples can also be replaced by any complex image or text information. The production the coating z. B. as an imprint usually uses the possibilities of printing technology.

Furthermore, in the following examples only the design and mutual association of the embossed structure and the coating are shown in order to be able to clearly show the optical effects of the optically variable structure according to the invention.

Fig. 1

im Querschnitt ein Prägewerkzeug (Fig. 1a), ein erfindungsgemäßes Prägewerkzeug (Fig. 1b) und ein mit dem erfindungsgemäßen Prägewerkzeug geprägtes Substrat (Fig. 1c) in einer ersten Ausführungsform,

Fig. 2

im Querschnitt ein Prägewerkzeug (Fig. 2a), ein erfindungsgemäßes Prägewerkzeug (Fig. 2b) und ein mit dem erfindungsgemäßen Prägewerkzeug geprägtes Substrat (Fig. 2c) in einer zweiten Ausführungsform.

In detail show schematically:

Fig. 1

an embossing tool in cross section ( Fig. 1a ), an embossing tool according to the invention ( Figure 1b ) and a substrate embossed with the embossing tool according to the invention ( Figure 1c ) in a first embodiment,

Fig. 2

an embossing tool in cross section ( Fig. 2a ), an embossing tool according to the invention ( Figure 2b ) and a substrate embossed with the embossing tool according to the invention ( Figure 2c ) in a second embodiment.

Fig. 1 shows in cross section in Fig. 1a an embossing tool in the form of an embossing plate 1 with a first elevation 2. The first elevation 2 is designed in the form of a dome-shaped elevation, the upper edge of the first elevation 2 having a height d ₁ from the upper edge of the embossing plate 1.

This first increase 2 is according to Figure 1b provided with second elevations 3, the second elevations 3 protruding from the first elevation 2 with a height d ₂ . The dome-shaped first elevation 2 overlaps with the smaller second elevations 3.

Figure 1c shows a substrate 4, for example a paper or cardboard, which is made with the embossing tool Figure 1b was coined. The substrate 4 was acted upon from its underside with the embossing tool and from the upper side with an impression cylinder, so that the dome-shaped first elevation 2 as a dome-shaped first recess 5, indicated by the dashed line, and the second elevations 3 as the second Map wells 7. The dome-shaped first depression 5 has a depth t ₁ ′ and the second elevations 7 a depth t ₂ ′ in relation to the lower edge of the substrate 4. Here, the depth t ₁ 'or its amount is slightly smaller than the height d ₁ or its amount and the depth t ₂ ' or its amount is slightly smaller than the height d ₂ or its amount.

The first elevation 2 is formed as an elevation 6 on the upper side of the substrate 4.

Fig. 2 shows in cross section in Fig. 2a an embossing tool in the form of an embossing plate 11 with a first recess 12. The first recess 12 is designed in the form of a dome-shaped recess, the upper edge of the first recess 12 having a depth t ₁ from the upper edge of the embossing plate 11.

This first recess 12 is according to Figure 2b provided with second depressions 13, the second depressions 13 protruding from the first depression 12 to a depth t ₂ . The dome-shaped first depression 12 is superimposed on the smaller second depressions 13.

Figure 2c shows a substrate 14, for example a paper or cardboard, which is made with the embossing tool Figure 2b was coined. The substrate 4 was acted upon from its underside with the embossing tool and from the top with an impression cylinder, so that in its underside map the dome-shaped first depression 12 as a dome-shaped first elevation 15 and the second depressions 13 as second depressions 17. The dome-shaped first elevation 15 has a height d ₁ ′ and the second depressions 17 a depth d ₂ ′ in relation to the lower edge of the substrate 14. Here, the height d ₁ 'or its amount is slightly smaller than the depth t ₁ or its amount and the depth d ₂ ' or its amount is slightly smaller than the depth t ₂ or its amount.

The first depression 12 is formed as a depression 16 on the top side of the substrate 14.

The shape of the elevation 6 or the depression 16 can differ greatly due to different or varying material properties of the substrate, particularly in terms of thickness, volume and texture as well as due to different back pressure conditions.

Claims (8)

1. Security element with an optically variable structure which has an embossed structure and a coating, wherein the embossed structure and the coating are combined in such a way that at least parts of the coating are completely visible when viewed vertically but are hidden when viewed obliquely, so that different information becomes visible as the viewing direction is changed, wherein the embossed structure comprises a first embossed element (5, 6, 15, 16) having an embossing depth (d₁', t₁') of more than 30 µm and second embossed elements (7, 17) having an embossing depth (d₂', t₂') of more than 10 µm, wherein the second embossed elements (7,17) are arranged within the first embossed elements (5, 6, 15, 16) and overlap the latter, wherein the security element consists of a substrate (4, 14) made of paper or cardboard and the embossed structure is embossed into the substrate (4, 14), characterized in that the first embossed element (5, 6, 15,16) is at least three times larger than the second embossed elements (7,17), both in the lateral and vertical dimension.
2. Security element according to Claim 1, characterized in that the first embossed element (5, 6,15,16) consists of a channel-shaped or hipped-roof-shaped or dome-shaped recess or elevation.
3. Security element according to at least one of the preceding claims, characterized in that the first embossed element (5, 6, 15, 16) has a depth of 30 µm to 1000 µm, preferably of 30 µm to 400 µm and particularly preferably of 50 µm to 200 µm.
4. Embossing tool for producing a security element with an optically variable structure which has an embossed structure and a coating, wherein the embossed structure and the coating are combined in such a way that at least parts of the coating are completely visible when viewed vertically but are hidden when viewed obliquely, so that different information becomes visible as the viewing direction is changed, wherein the embossing tool has a first elevation (2, 12) or a recess for producing a first embossed element having a depth (d₁, t₁) of more than 30 µm, and wherein second elevations (3, 13) or recesses having a depth (d₂, t₂) of more than 10 µm are arranged within the first elevation (2, 12) or recess, so that the first elevation (2, 12) or recess and the second elevations (3, 13) or recesses overlap, characterized in that the first elevation (2, 12) or recess of the embossing tool is at least three times larger than the second elevations (3, 13) or recesses of the embossing tool, both in the lateral and vertical dimension.
5. Embossing tool according to Claim 4, characterized in that the first elevation (2, 12) or recess is configured in the shape of a channel or hipped roof or dome.
6. Embossing tool according to Claim 4 or 5, characterized in that the embossing tool is an embossing cylinder, an embossing punch or a printing plate, in particular an intaglio printing plate.
7. Embossing tool according to one of Claims 4 to 6, characterized in that the security element consists of a substrate (4, 14) made of paper or cardboard.
8. Embossing tool according to one of Claims 4 to 7, characterized in that the first elevation (2, 12) or recess of the embossing tool has a depth of 30 µm to 1000 µm, preferably of 30 µm to 400 µm and particularly preferably of 50 µm to 200 µm.

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