EP3498488B1 - Manufacturing method of a security element with an optical variable structure - Google Patents

Description

The invention relates to a method for producing a security element with an optically variable structure which has an embossed structure of embossed elements which is combined with a coating that contrasts with the surface of the security element in such a way that at least partial areas of the coating are visible when viewed from a first viewing angle range Viewing under a second viewing angle range, however, are at least partially covered, so that a tilting effect occurs when the security element is tilted and / or rotated about an axis.

To ward off attempts at forgery, new security elements are constantly being sought for any data carrier that represents a value. This also applies to trademark protection. Elements that have an embossed structure that can be haptically felt and can therefore be checked easily without aids are advantageous.

Embossing forms for gravure or letterpress are used. A special application are tactile structures that can be easily recognized by people with visual impairment, for example Braille or labels that are typically defined by points or line structures based on the system or quantity and thus, for example, a nomination or the value of a banknote represent.

Embossed structures are also used for optically variable security elements in which a grid of embossed structures, the so-called Embossing grid, clearly assigned to a grid of printed structures, the so-called background printing. These security elements are known from, for example WO 2006/018232 A1 , WO 2009/013000 A2 , WO 2010/075979 A1 , WO 2013/045056 A1 , WO 2013/045055 A1 ,

WO 2013/045054 A1 , EP 2746059 A2 and WO 2016/020066 A2 and are used not only on value or security documents, such as banknotes or identity documents, but also on packaging for higher-value products, such as pharmaceuticals, cosmetics or cigarettes.

The special feature of the embossed structures known from the prior art lies in the exact registration between the structures of the background print and the structures of the embossed grid. This exact registration of the two grids leads to the desired result of an optically variable appearance in which different information becomes visible by changing the viewing angle. Even slight deviations from the exact registration lead to undesirable effects, such as those from the WO 2008/049566 A2 are known.

the end WO 02/20280 A1 an optically variable structure is known which consists of an imprint and an embossed structure superimposed on this imprint. The entire area provided with printing and embossing is divided into sub-areas in which either the printing or the embossing can be varied uniformly for the entire surface. The other part (embossing or imprint) is made the same in all sub-areas, ie it has the same regularities in all sub-areas.

the end EP 2 284 805 A2 an optically variable structure is known which consists of a coating and an embossed structure superimposed on this coating. The embossed structure has non-linear embossed elements which are combined with the coating in such a way that different information becomes visible when the viewing direction is changed. The non-linear embossed elements are characterized in particular by at least three flanks, these flanks having dimensions that enable the shadowing effect according to the invention.

The invention is therefore based on the object of developing a generic security element in such a way that different optically variable effects can be generated using simple means in accordance with different customer requirements. The technical effort involved in changing the respective optically variable effects should be as low as possible, for example in the case of strongly changing order sequences such as short runs or individualized digital printing.

This object is achieved by the features of the independent claim. A further development of the invention is the subject of dependent claim 2.

According to the invention, the area occupied by the entire embossed structure on the security element is larger than the area occupied by the entire first coating on the security element, the embossed structure and the first coating at least partially overlapping in relation to the top view of the security element. If different security elements with different optically variable structures with different tilting effects are to be produced, the embossed structure remains unchanged and only the first coating is adapted to the different optically variable structures. According to the invention, a uniform embossed grid, which consists of a grid-shaped arrangement of embossed structures, is combined with different first printing grids in order to obtain a large number of different optically variable effects that can be individually adapted to customer requirements. The embossing information is therefore always the same and only the printing screen is different.

According to the invention, the area which the entire embossed structure occupies on the security element is made larger than the area which the entire first coating occupies on the security element. The embossed structure and the first coating are arranged at least partially overlapping in relation to the top view of the security element. If the optically variable structure is changed, the embossed structure is not changed according to the invention and only the first coating is adapted to the changed optically variable structure.

According to a preferred embodiment, the embossed structure and the first coating completely overlap in relation to the top view of the security element, the contour delimiting the first coating not touching the contour delimiting the embossed structure. The first coating is thus arranged completely within the embossed structure and does not touch the outer boundary of the embossed structure at any point.

According to a preferred embodiment, the embossed elements consist of a plurality of embossed structures arranged in a grid. The embossed Structures are particularly preferably designed as point-like and / or linear structures, with linear structures being able to be linear, undulating or curved as desired. Point-like structures can, for example, have a round, triangular, square, rectangular or any polygonal base area, such as those from WO 2006/018232 A1 or WO 2013/045056 A1 are known.

The first coating can also consist of a plurality of first printed elements arranged in a grid, the grid of the printed elements being adapted to the grid of the embossed structures. The printed elements are particularly preferably designed as point and / or line-shaped structures in accordance with the embossed structures described in the previous paragraph. Line-shaped structures can therefore be designed, for example, as straight, wavy or curved in any way, point-shaped structures, for example, have a round, triangular, square, rectangular or any polygonal base area.

A grid is a regular, repetitive arrangement of these embossed or printed structures or elements. Such an arrangement is, for example, a sequence of lines aligned parallel to one another at a certain distance from one another. The individual lines can also be formed from a large number of points that are spaced regularly, the same or irregularly from one another. Instead of a large number of points, a large number of points, line segments, triangular, square or polygonal and / or arbitrarily shaped elements or a mixture of these elements is also possible. Mixed forms can also be created by combining images in different grid types and / or resolutions in order to obtain a further optically variable effect. Thus, an image that appears uniform to the observer when viewed vertically can appear different in color in partial areas when it is tilted or rotated.

According to the invention, the security element has a second coating, which preferably consists of a plurality of second printed elements arranged in a grid, which surrounds the first coating and wherein the grid of the printed elements is not adapted to the grid of the embossed structures. The printing screen is thus divided into at least two different areas, a first printing screen which, together with the embossed screen, produces an optically variable effect, and a second printing screen which, together with the embossed screen, does not produce an optically variable effect. In order to "extinguish" an optical effect, it is advantageous to provide an at least twice higher screen width of the printing screen in relation to the embossed structure, similar to the Nyquist-Shannon or WKS scanning theorem. For example, the screen width of the embossing is 30 lines per cm, which corresponds to a line width of 300 μm, and the screen width of the second printing screen is 80 lines per cm. The first print raster, on the other hand, preferably has raster widths of 10 lines per cm to 80 lines per cm, particularly preferably 20 lines per cm to 40 lines per cm.

Instead of a grid, the second coating can also consist of a colored surface, for example a single or multi-colored print. This imprint surrounds the first coating and can also be configured to overlap it and thereby protrude into the first coating. The colored surface can also continue into the areas surrounding the embossed structure. The second coating does not have to be limited to the area of the embossed structure.

The embodiment according to the invention makes it possible particularly preferably to use an embossing form with an embossing grid, the area of which in the lateral direction is larger than the area in which the different optically variable effects are to be arranged, around different printing grids, which can be different in appearance and dimensions to enable within the embossing grid. In the area of the embossing grid outside the area with the optically variable effect, the printing grid is designed in such a way that no optically variable effect is generated.

For this purpose, the design in the desired embossed area is provided with the background grid adapted to the embossed grid and provided on the outside with a finer or significantly coarser grid than the embossed grid, so that the outer area does not have any discernible optically variable effect together with the embossed structure.

The production of the security element according to the invention is particularly preferably carried out with a predetermined, uniform embossing grid or embossing tool, and a first printing grid or printing tool that is matched to the embossing grid and can be individually adapted to customer requirements.

The printing grids preferably consist of individual grid elements, each of which has different colors, preferably one to twelve different colors and particularly preferably one to four different colors. According to a preferred embodiment, the extent of the embossing structure corresponds to the extent of the embossing tool. The embossed structure covers the entire surface of the embossing tool, which forms the embossed structure in the substrate of the security element.

Advantages of the invention are in particular a cost saving through only one uniform embossing tool, since many different optically variable designs can be realized with the one embossing tool. This results in short set-up times and a high degree of flexibility, low reject rates and a large area of application.

An optically variable structure within the meaning of this invention is a structure whose visual appearance changes when the element is tilted or rotated. For example, when the optically variable structure is tilted or rotated, its color changes, a bar appears to move from one side of the element to another side, different characters are displayed when tilted or rotated, or a so-called pumping effect results in the form of an enlarging or decreasing effect Outline of an image motif.

Documents of value for which such a security element can be used are, in particular, banknotes, shares, bonds, certificates, vouchers, checks, high-quality entry tickets, but also other forgery-prone papers, such as passports and other identification documents, as well as cards such as credit 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, outer packaging, banderoles and the like.

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

In the context of this invention, the positional accuracy of the printing screen and embossing screen or other elements with respect to one another on the front and / or back of a substrate is referred to as register or register. For example, in the case of parts of print images that complement each other to form an overall print image, even slight deviations of less than 0.1 mm between the respective print images significantly disturb the visual impression when viewed through. DIN 16500-2: 1987-01 defines register as the accuracy in printing technology with which the intended reproduction quality of the details to be reproduced is achieved or maintained. Individual items, for example personalized one-time products, can also have a slightly higher register inaccuracy, since the focus here is on the one-off effect or the uniqueness of the product.

The optically variable structure particularly preferably shows information in the form of a pattern designed and visually perceptible representation. This can form, for example, 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 is applied to the substrate, 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-colored 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.

The advantages of the invention are explained on the basis of the following exemplary embodiments and the supplementary figures. 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 are used exclusively to improve the clarity. Furthermore, the embodiments described in the following exemplary embodiments are reduced to the essential core information for better understanding. In the practical implementation, much more complex patterns or images can be used.

Fig. 1

in Draufsicht eine Ausführungsform eines Prägerasters,

Fig. 2

in Draufsicht eine erste Ausführungsform einer erfindungsgemäßen Kombination des Prägerasters aus Fig. 1 mit zwei Druckrastern und hierbei in Fig. 2a ein erstes Druckraster, in Fig. 2b ein zweites Druckraster und in Fig. 2c die Kombination des ersten und zweiten Druckrasters mit dem Prägeraster,

Fig. 3

in Draufsicht eine zweite Ausführungsform einer erfindungsgemäßen Kombination des Prägerasters aus Fig. 1 mit zwei Druckrastern und hierbei in Fig. 3a ein erstes Druckraster, in Fig. 3b ein zweites Druckraster und in Fig. 3c die Kombination des ersten und zweiten Druckrasters mit dem Prägeraster.

In detail show schematically:

Fig. 1

in plan view an embodiment of an embossed grid,

Fig. 2

in plan view a first embodiment of a combination of the embossing grid according to the invention Fig. 1 with two printing grids and here in Fig. 2a a first print screen, in Figure 2b a second print raster and in Figure 2c the combination of the first and second printing grid with the embossing grid,

Fig. 3

in plan view a second embodiment of a combination of the embossing grid according to the invention Fig. 1 with two printing grids and here in Fig. 3a a first print screen, in Figure 3b a second print screen and in Figure 3c the combination of the first and second printing grid with the embossing grid.

the Fig. 1 shows a plan view of an embodiment of an embossed grid, which consists of a grid of regularly arranged embossed structures 1, which have a circular base. The embossing grid was produced with an embossing die which, depending on the substrate to be embossed, has an embossing grid with slightly reduced embossing structures. If the stamp has raised embossed structures, there are recessed embossed structures in the substrate and vice versa. In the case of a circular base area, the embossed structures are preferably designed as hemispherical structures. Any other shapes of base areas are of course possible, for example polygons with pyramid-shaped embossed structures or also elongated, line-like structures.

Fig. 2 shows a top view of a first embodiment of a combination of the embossing grid according to the invention Fig. 1 with two print grids Fig. 2a and Figure 2b .

Here shows Fig. 2a a first printing raster, the outline of which has the overall shape of a triangle. The individual grid elements 2, 3, 4 have a circular base area corresponding to the embossed grid, with each individual grid element of the embossed grid 1 having three grid elements 2, 3 and 4 are assigned, which for example have different colors, 2 is red, 3 is green and 4 is blue, which is shown in the figures by different hatching. The grid elements 2, 3 and 4 thus lie on different areas of the flank of the grid element of the embossed grid 1, so that a viewer sees different colors from different viewing directions. This results in an optically variable effect for a viewer in the form of a color shift effect that is dependent on the viewing angle.

Figure 2b shows a second printing raster which is designed in such a way that it comprises the first printing raster Fig. 2a surrounds and has a recess in the form of a triangle, the dimensions of which are based on the outline Fig. 2a is equivalent to. This print raster also consists of three different raster elements 5, 6 and 7 which, like raster elements 2, 3 and 4, have different colors. In contrast to the grid elements 2, 3 and 4, the grid elements 5, 6 and 7 are not assigned to any grid element of the embossed grid 1, but are distributed as desired. There is thus no optically variable effect due to the raster elements 5, 6 and 7, but a mixed color independent of the viewing angle.

Figure 2c shows the combination of the first print raster Fig. 2a and the second print screen Figure 2b with the embossing grid Fig. 1 . Only in the triangular area in which the grid elements 2, 3 and 4 are arranged does an optically variable effect arise for a viewer in the form of a color shift effect dependent on the viewing angle, outside this area a mixed color independent of the viewing angle.

In the Fig. 3 The embodiment shown corresponds to the embodiment from FIG Fig. 2 , being in contrast to the embodiment from Fig. 2 the first Print grid according to Fig. 3a overall has an outline in the form of a rectangle. Here, too, is in accordance Figure 3b a second printing grid designed so that it is the first printing grid Fig. 3a surrounds and has a recess in the form of a rectangle, the dimensions of which are based on the outline Fig. 3a is equivalent to. Figure 3c shows the combination of the first print raster Fig. 3a and the second print screen Figure 3b with the embossing grid Fig. 1 .

Claims (2)

1. Method for producing a security element with an optically variable structure which has an embossing structure consisting of embossing elements (1), which embossing structure is combined with a first coating which contrasts with the surface of the security element, in such a way that at least part regions of the coating are visible in the case of viewing from a first viewing angle range, but are at least partially concealed in the case of viewing at a second viewing angle range, with the result that a tilting effect is produced in the case of tilting and/ or rotating of the security element about an axis, the area which the entire embossing structure takes up on the security element being configured to be greater than the area which the entire first coating takes up on the security element, the embossing structure and the first coating being arranged so as to overlap at least partially in relation to the top view of the security element, the embossing structure not being changed in the case of a change of the optically variable structure, and the first coating being adapted to the changed optically variable structure, the embossing elements (1) consisting of a multiplicity of embossed structures which are arranged in a pattern, and the first coating consisting of a multiplicity of first printed elements (2, 3, 4) which are arranged in a pattern, the pattern of the printed elements (2, 3, 4) being adapted to the pattern of the embossed structures, the security element having a second coating which consists of a multiplicity of second printed elements (5, 6, 7) which are arranged in a pattern, characterized in that the second coating surrounds the first coating in an adjoining manner, and the pattern of the printed elements (5, 6, 7) is not adapted to the pattern of the embossed structures.
2. Method according to Claim 1, characterized in that the embossing structure and the first coating are arranged so as to overlap completely in relation to the top view of the security element, the outline which delimits the first coating not making contact with the outline which delimits the embossing structure.

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