EP4013624B1 - Optically variable security element - Google Patents

Description

The invention relates to an optically variable security element with a multi-colored reflective surface area for securing valuables. The invention also relates to a method for producing such a security element and a data carrier equipped with such a security element.

Data carriers, such as valuables or identification documents, but also other valuables, such as branded items, are often provided with security elements for security purposes, which allow the authenticity of the data carrier to be checked and which at the same time serve as protection against unauthorized reproduction. The security elements can be designed, for example, in the form of a security thread embedded in a banknote, a cover film for a banknote with a hole, an applied security strip, a self-supporting transfer element or also in the form of a feature area printed directly on a document of value.

Security elements with a viewing angle-dependent or three-dimensional appearance play a special role in authenticity assurance, as these cannot be reproduced even with the most modern copying machines. For this purpose, the security elements are equipped with optically variable elements that give the viewer a different image impression at different viewing angles and, for example, show a different color or brightness impression and/or a different graphic motif depending on the viewing angle. In the prior art, optically variable effects are described, for example, movement effects, pump effects, depth effects or flip effects, which are realized with the help of holograms, microlenses or micromirrors.

WO 03/082598 A2 relates to a security element with two overlapping optically variable structures, the second structure being visible through the first structure. WO 2015/181289 A1 shows the preamble of claim 1.

Based on this, the object of the invention is to further increase the security against forgery and the visual attractiveness of generic optically variable security elements. In particular, optically variable security elements with two or more different appearances or effects in different colors should be provided, which are ideally simple and inexpensive to produce.

This task is solved by the features of the independent claims. Further developments of the invention are the subject of the dependent claims.

To solve the stated problem, the invention contains an optically variable security element, with a multi-colored reflective surface area, which can be used in particular to secure valuables.

The surface extent of the security element defines a plane and a z-axis perpendicular to it. According to the invention, the multicolored reflective surface area of the security element contains two relief structures which are arranged at different height levels in the z direction and thus form a lower-lying and a higher-lying relief structure.

The lower-lying relief structure is provided with a first color coating following the relief gradient and the higher-lying relief structure is provided with a second color coating following the relief gradient.

In the z direction, a translucent colored flat structure is arranged at a height step between the two relief structures. The two relief structures and the flat structure also overlap in an overlap area. In this overlap area, the second color coating of the higher relief structure has at least one recess in which the lower relief structure with the combined color effect of the colored flat structure and the first color coating appears when the security element is viewed. The higher relief structure and/or the lower relief structure are formed by micromirror arrangements with directed micromirrors.

The above-mentioned overlap of the structures can be partial or complete, so it is also possible in particular for the two relief structures and the flat structure to be designed to be congruent with one another. The overlap refers to the relative lateral position of the relief structures and the flat structure in the plane defined by the surface extent of the security element. The security element is designed to be viewed in reflection from the positive z-direction, so the higher-lying relief structure, the flat structure and the deeper-lying relief structure are increasingly further away from the viewer.

The translucent colored flat structure is particularly advantageously formed by a laminating varnish layer, for example a glazing-colored laminating varnish layer, a colored primer layer or a printed color layer. The translucent colored flat structure can contain, in particular, coloring pigments and/or a dye as colorants.

The light transmission of the flat structure is advantageously between 20% and 80%. Since the flat structure is both translucent and colored, the color effects of the flat structure and the first color coating combine for the viewer in the recess(es) to create an overall color impression.

In contrast to the relief structures, the translucent colored flat structure is not structured in height, but is flat. The flat structure can in particular be applied directly to a carrier film or to a flat substrate layer, for example a leveling lacquer layer.

In an advantageous variant of the invention, the second color coating of the higher-lying relief structure is designed in the overlap area as a regular or irregular grid with grid elements and grid spaces. The grid spaces represent the above-mentioned recesses. In this variant, the dimensions of the grid elements and/or grid spaces are below 140 μm, at least in one direction. Preferably, the dimensions of the grid elements and/or grid spaces are even below 140 μm in one or both lateral directions, preferably between 20 μm and 100 μm, in particular between 20 μm and 60 μm.

In an advantageous embodiment, the grid elements and grid spaces of the grid have the same shape and preferably also the same size. The grid elements and/or the grid spaces can in particular be formed by strip-shaped, square, triangular or other polygonal elements, but can also have irregular shapes. The grid itself can be regular, i.e. have a regular arrangement of grid elements and grid spaces, but can also be an irregular grid, for example a stochastic grid, in which the grid elements and / or grid spaces have irregular spacing and / or sizes and / or shapes. The area coverage of the grid by the grid elements is advantageous between 30% and 70%, preferably between 40% and 60%, especially around 50%.

In a further variant of the invention, the second color coating in the overlap area advantageously contains partial areas that have lateral dimensions of more than 140 μm, and / or that the second color coating of the higher-lying relief structure is produced in the overlap area with recesses that have lateral dimensions of more than 140 μm . The lateral dimensions of at least one partial area and/or at least one recess are preferably more than 250 μm, preferably more than 500 μm and in particular more than 1 mm. The subareas mentioned can be provided as an alternative or in addition to the grid described above.

The first color coating of the deeper relief structure is advantageously opaque in the overlap area. Alternatively or additionally, the first color coating mentioned is formed over the entire surface in the overlap area, i.e. without recesses.

The colored flat structure is preferably designed in a uniform color, at least in the area of the recess. The flat structure is uniformly colored at least in a size of more than 140 μm, preferably more than 250 μm, more preferably more than 500 μm and in particular more than 1 mm. Preferably, the flat structure has a uniform color throughout the entire overlap area. Outside - the recess or the overlap area - the flat structure can have one or more other colors, i.e. in particular include another (or several other) colorants. For larger recesses, especially when partial areas of the recess are larger, each of which allows a separate color perception (minimally more than 500µm, but usually more than 1 mm), the colored flat structure can be designed in different colors in parts of the recess. The flat structure can therefore be multicolored overall.

The first and/or second color coating is preferably a reflective color coating. One or both color coatings can be formed in particular by metallization, for example of aluminum, silver or an alloy, for example of copper and aluminum, by thin-film structures, in particular color-shifting thin-film structures or color-stable color-filtering thin-film structures (different colors in remission and transmission), or silicon-aluminum thin films be. The first and/or second color coating can also represent a translucent image made up of several translucent colors, which is backed with a mirror coating, for example made of aluminum. Luminescent colors, in particular fluorescent colors with a metallic mirror coating, can also be considered as color coatings. The first and/or second color coating can also be formed by structural colors, in particular by nano- and binary structures, which are embossed on or into the micromirrors of a micromirror arrangement. Finally, nanoparticle colors can also be considered as color coatings, such as gold-blue particles, various effect pigments, color-shifting pigments or super silver.

In an advantageous variant of the invention, the first and second color coatings are of identical material; for example, both color coatings can be formed by an aluminum layer. Since the colored flat structure is arranged between the two relief structures, it only influences the color impression of the deeper relief structure, but not that of the higher relief structure. This is where the two relief structures appear Even with the same material color coating with different color impressions.

The color impressions are different, they differ in their hue. The color tones (of the two color impressions) are preferably chromatic tones. The color of the colored flat structure is a chromatic color. The color of the first (and/or the second) color coating can be a chromatic color or an achromatic color.

The higher relief structure and/or the lower relief structure are formed by micromirror arrangements with directed micromirrors.

The micromirrors are formed in particular by non-diffractive mirrors and do not produce any color splitting. Planar mirrors, concave mirrors and/or Fresnel-like mirrors can preferably be used. The individual directional micromirrors of the micromirror arrangement either reflect the light to the viewer or not (bright or dark), depending on their orientation for the viewing angle. The lateral dimensions of the micromirrors are advantageously below 20 μm, preferably below 10 μm, but preferably also above 2 μm, in particular above 3 μm or even above 5 μm. In principle, other relief structures, in particular embossed Fresnel lenses, concave mirrors, hologram structures, nanostructures or diffractive blazed gratings, can also be used instead of micromirrors.

The alignment of the micromirrors of the higher-lying relief structure and/or the deeper-lying relief structure advantageously varies depending on the location in order to produce a predetermined motif, in particular a three-dimensional motif or a movement motif. The alignment The micromirror can be freely selected and is essentially determined only by the given motif, but not by the alignment of neighboring micromirrors.

The two relief structures advantageously provide a color change for an unchanged motif depending on the viewing angle or provide a color change together with a motif change. The motifs of the two relief structures can differ in particular in terms of shape (e.g. head, apple or number), movement (static to moving or moving to static, with linear, rotating and/or pumping movement) and/or dimensionality (2D to 3D, or different three-dimensional with a positive or negative curved appearance or floating in front of or behind a plane) of the motif.

In an advantageous embodiment, it is provided that the higher-lying relief structure generates a first motif with a first color impression that is visible from a first viewing angle range and the lower-lying relief structure generates a second motif with a second, different color impression that is visible from a second viewing angle range is, wherein the first and second viewing angle ranges do not overlap. When tilted, the security element then shows a binary color and effect change without an overlap area. The two viewing angle ranges can be adjacent to one another or only be separated by an angular distance of a few degrees, so that the associated image impressions change almost seamlessly for the viewer.

The higher relief structure can also produce a first movement motif with a first color impression and the lower relief structure can create a second movement motif with a second, different one Generate a color impression, with the first and second movement motifs moving offset from one another or moving against one another when the security element is tilted and thereby crossing each other in an overlapping position in which both movement motifs are visible.

The two relief structures can also generate motifs or movement motifs that are simultaneously visible in the same surface area, that is to say have at least partially overlapping viewing angle areas. Since the vertical distance between the two relief structures is very small and is well below the resolution limit of the naked eye, the appearances generated by the two relief structures appear to be present at the same place at the same time to an observer.

• Ein binärer Motivflip zwischen gewölbten und/oder dreidimensional erscheinenden Bildmotiven mit binärem Farbwechsel. Ein erster Betrachtungswinkelbereich erstreckt sich beispielsweise von +5° bis +20° bezogen auf eine Flächennormale des Sicherheitselements, ein zweiter Betrachtungswinkelbereich von -5° bis -20°. Das erste und zweite Motiv können auch identisch sein, so dass sich ein reiner binärer Farbwechsel ergibt.
• Pump- oder Laufeffekte mit unterschiedlichen Farben, die sich örtlich kreuzen, beispielsweise entgegengesetzt laufen. Ein Betrachtungswinkelbereich für das erste Bewegungsmotiv erstreckt sich beispielsweise von -20° bis +20°, ein Betrachtungswinkelbereich für das zweite, gegenläufige Bewegungsmotiv umgekehrt von +20° bis -20°. Bei versetzt laufenden Bewegungsmotiven läuft ein Motiv beispielsweise von -20° bis +10°, das andere Motiv von -10° bis +20°.
• Ein binärer Motivflip, bei dem die gewölbten und/oder dreidimensional erscheinenden verschiedenfarbigen Bildmotive ineinander liegen und/oder einander überschneiden. Beim Kippen findet insbesondere ein gleichzeitiger Farbtausch des inneren und des äußeren Motivs bzw. der überschneidenden Motivteile statt.

The following examples of variants have proven to be particularly visually attractive:

• A binary motif flip between curved and/or three-dimensional image motifs with a binary color change. A first viewing angle range extends, for example, from +5° to +20° based on a surface normal of the security element, a second viewing angle range from -5° to -20°. The first and second motifs can also be identical, resulting in a purely binary color change.
• Pumping or running effects with different colors that cross each other locally, for example running in opposite directions. A viewing angle range for the first movement motif extends, for example, from -20° to +20°, and a viewing angle range for the second, opposing movement motif extends from +20° to -20°. For example, with staggered movement motifs, one motif runs from -20° to +10°, the other motif from -10° to +20°.
• A binary motif flip in which the curved and/or three-dimensionally appearing different colored image motifs lie within one another and/or overlap one another. When tilting, there is a simultaneous color change of the inner and outer motif or the overlapping parts of the motif.

The different height levels in which the two relief structures and the flat structure are arranged advantageously have a distance in the z direction between 5 µm and 100 µm, preferably between 10 µm and 50 µm. The small vertical distance between the structures involved is not noticeable when looking at the security element. The reference point for the height level of a relief structure is the base area of the relief structure, for example at the base of a micromirror embossing.

The invention also includes a data carrier with an optically variable security element of the type described, the lower-lying relief structure being closer to a surface of the data carrier and the higher-lying relief structure being further away from said surface of the data carrier. In an expedient variant, the security element is arranged in an opaque area of the data carrier.

• ein Träger bereitgestellt wird, dessen Flächenausdehnung eine Ebene und eine darauf senkrecht stehende z-Achse definiert,
• der Träger mit einem mehrfarbigen reflektiven Flächenbereich versehen wird, der zwei Reliefstrukturen enthält, die in z-Richtung in unterschiedlichen Höhenstufen angeordnet sind, und eine tiefer liegende und eine höher liegende Reliefstruktur bilden,
• die tiefer liegende Reliefstruktur mit einer dem Reliefverlauf folgenden ersten Farbbeschichtung und die die höher liegende Reliefstruktur mit einer dem Reliefverlauf folgenden zweiten Farbbeschichtung versehen wird,
• in z-Richtung auf einer Höhenstufe zwischen den beiden Reliefstrukturen eine lichtdurchlässige farbige Flachstruktur angeordnet wird,
• die beiden Reliefstrukturen und die Flachstruktur in einem Überlappungsbereich überlappend ausgebildet werden, und
• die zweite Farbbeschichtung der höher liegenden Reliefstruktur in dem Überlappungsbereich mit zumindest einer Aussparung ausgebildet wird, in der bei Betrachtung des Sicherheitselements die tiefer liegende Reliefstruktur mit der kombinierten Farbwirkung der farbigen Flachstruktur und der ersten Farbbeschichtung in Erscheinung tritt.

Finally, the invention also contains a method for producing an optically variable security element, preferably a security element of the type described in more detail above, in which

• a carrier is provided, the surface extent of which defines a plane and a z-axis perpendicular thereto,
• the carrier is provided with a multi-colored reflective surface area which contains two relief structures which are arranged at different height levels in the z-direction and form a lower-lying and a higher-lying relief structure,
• the lower-lying relief structure is provided with a first color coating following the relief gradient and the higher-lying relief structure is provided with a second color coating following the relief gradient,
• A translucent colored flat structure is arranged in the z direction at a height level between the two relief structures,
• the two relief structures and the flat structure are designed to overlap in an overlap area, and
• the second color coating of the higher relief structure is formed in the overlap area with at least one recess in which, when viewing the security element, the lower relief structure with the combined color effect of the colored flat structure and the first color coating appears.

The higher-lying relief structure and/or the deeper-lying relief structure is formed by micromirror arrangements with directed micromirrors.

In an advantageous procedure, it is provided that two layer structures are produced separately, in which the relief structures mentioned are produced on separate supports and provided with the respective color coating following the relief gradient, and that the two layer structures produced are covered by a translucent colored laminating varnish layer are laminated together, which in the laminated state forms the flat structure of the security element.

In another, also advantageous method, it is provided that the higher-lying relief structure is first created with the second color coating on a support, the coated relief structure is leveled with a cover layer, and a translucent, non-height-structured color layer is applied to the cover layer, which forms the flat structure of the security element, and that the deeper relief structure is created on the translucent color layer with the first color coating.

Finally, according to a further, also advantageous method, it can be provided that a carrier is provided with a translucent, non-height-structured color layer on one of its main surfaces, that the relief structures mentioned are applied to the opposite main surfaces of the color-coated carrier, so that the translucent color layer has an intermediate Flat structure lying on the relief structures forms, and that the relief structures are provided with the respective first or second color coating.

Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, which are not reproduced to scale and proportions in order to increase clarity.

Fig. 1

eine schematische Darstellung einer Banknote mit einem erfindungsgemäßen optisch variablen Sicherheitselement,

Fig. 2

schematisch einen Ausschnitt des Sicherheitselements der Fig. 1 im Querschnitt,

Fig. 3

in (a) bis (d) einige konkrete vorteilhafte Ausgestaltungen des Rasters der Farbbeschichtung der Mikrospiegelprägung in Aufsicht,

Fig. 4

eine andere Variante eines erfindungsgemäßen Sicherheitselements im Querschnitt,

Fig. 5

ein weiteres Ausführungsbeispiel eines erfindungsgemäßen Sicherheitselements mit einem gegenüber den Gestaltungen der Figuren 2 und 4 abgewandelten Schichtaufbau, und

Fig. 6

ein weiteres Ausführungsbeispiel der Erfindung im Querschnitt.

Show it:

Fig. 1

a schematic representation of a banknote with an optically variable security element according to the invention,

Fig. 2

schematically a section of the security element Fig. 1 in cross section,

Fig. 3

in (a) to (d) some concrete advantageous embodiments of the grid of the color coating of the micro-mirror embossing in top view,

Fig. 4

another variant of a security element according to the invention in cross section,

Fig. 5

a further embodiment of a security element according to the invention with a compared to the designs of Figures 2 and 4 modified layer structure, and

Fig. 6

another embodiment of the invention in cross section.

The invention will now be explained using the example of security elements for banknotes. Figure 1 shows a schematic representation of a banknote 10 with an optically variable security element 12, which is designed in the form of a glued-on transfer element. However, it is understood that the invention is not limited to transfer elements and banknotes, but can be used for all types of security elements, for example labels on goods and packaging or for securing documents, ID cards, passports, credit cards, health cards and the like. For banknotes and similar documents In addition to transfer elements, training as a security thread or security strip can also be considered.

This in Fig. 1 The security element 12 shown is itself very flat, but still gives the viewer a three-dimensional impression and also shows a binary color and effect change when the banknote 10 is tilted. From a first viewing direction, the security element 12 shows a first, apparently from the plane of the Banknote 10 bulging motif 14-A, for example a curved representation of the value number "10", which appears with a first, for example shiny silver color impression. From a second viewing direction, a second motif 14-B appears to bulge out of the plane of the banknote 10, for example a curved representation of a coat of arms with a second color impression, for example shiny red.

When tilting 16 the banknote 10 or a corresponding change in the viewing direction, the appearance of the security element 12 suddenly jumps from the first to the second appearance or when tilting back from the second to the first appearance. The change in the motif and the color occurs simultaneously and without an intermediate or transitional stage in which both motifs or colors would be visible at the same time or one motif would be visible in the color of the other motif. The appearance therefore jumps seamlessly between two appearances 14-A, 14-B and is therefore referred to as a binary color and effect change.

The special structure of optically variable security elements according to the invention will now be described with reference to Fig. 2 explained in more detail, which is a section of the security element 12 applied to the banknote 10 shows schematically in cross section.

The security element 12 contains a flat, transparent, colorless carrier 18, which defines an xy plane and a z-axis perpendicular thereto due to its surface extent. The security element 12 is viewed in reflection from the positive z-direction, in the orientation of the Fig. 2 so laid out from above.

A multicolored reflective surface area 20 is constructed on the carrier 18 and comprises two relief structures 24, 34 and a translucent flat structure 44 arranged between the relief structures. Specifically, the relief structures 24, 34 are arranged at a height level H _P1 or H _P2 and the flat structure at a height level H _F , the relation H _P1 < H _F < H _P2 applying to the height levels. The relief structure 24 is therefore also referred to as the lower-lying relief structure and the relief structure 34 as the higher-lying relief structure. The height levels of the various structures are indicated from the underside of the security element 12, with which it is attached to the banknote 10. The higher relief structure is therefore closer to the viewer than the lower relief structure.

In the exemplary embodiment, the two relief structures each represent micromirror embossings or micromirror arrangements 24, 34, which are each formed from a large number of micromirrors inclined relative to the xy plane. The local angles of inclination of the micromirrors are chosen so that the relief structure of the micromirror arrangements 24, 34 creates a desired optical appearance after the color coating. As a reference point for specifying a height level of the micro-mirror embossing The base surfaces or base points of the micromirrors of the micromirror arrangements serve in each case.

The micromirror arrangements 24, 34 are each provided with a color coating in the form of a metallization 26, 36, which in the exemplary embodiment is formed by an opaque aluminum layer. The lower-lying micromirror arrangement 24 is provided with a continuous aluminum layer 26, while the aluminum layer 36 arranged on the higher-lying micromirror arrangement 34 has recesses 54 in order to give the viewer 40 a view of the deeper-lying structures, namely the Flat structure 44 and the relief structure 24 to enable.

In the exemplary embodiment, the flat structure 44 is formed by a continuous, red translucent laminating lacquer layer. In contrast to the relief structures 24, 34, the flat structure 44 is not structured in height. Due to their translucency, the viewer can look from the viewing direction 40-B in the area of the recesses 54 through the second micromirror arrangement 34 and the flat structure 44 onto the deeper metallized micromirror arrangement 24, 26, so that the color effects of the colored flat structure are reflected in the recess areas 54 44 and the metallization 26 combine.

To display the motif, the inclination angles of the micromirrors in the exemplary embodiment are chosen so that the higher micromirror arrangement 34 produces the curved representation of the value number "10" in a viewing angle range of +5° to +20° (viewing position 40-A) relative to the surface normal and the deeper micromirror arrangement 24 creates the curved representation of the coat of arms in a viewing angle range of -5 ° to -20 ° (viewing position 40-B).

The two micromirror arrangements 24, 34 and the colored flat structure 44 are arranged one above the other in the entire surface area 20 of the security element 12 in the exemplary embodiment. While the metallization 26 of the lower-lying micromirror arrangement 24 is formed continuously, the metallization 36 of the higher-lying micromirror arrangement 34 is designed in the form of a regular grid 50 of grid elements 52 and grid spaces 54. Specifically, the grid elements 52 and grid spaces 54 in the exemplary embodiment form a checkerboard pattern in which each field, i.e. each grid element 52 and each grid space 54, has a dimension of 100 μm x 100 μm. Since the micromirrors are usually significantly smaller, for example having an edge length of only 10 μm, the grid 50 of the color coating 36 falls differently than in the simplified schematic representation Fig. 2 , generally not with the grid of micromirrors of the micromirror arrangement 34.

When producing the security element 12, a first embossed lacquer layer 22 was applied to a first carrier film via a release layer, the desired relief structure of the micromirror arrangement 24 was embossed, the embossed structure was coated over the entire surface with an opaque aluminum layer 26 and the coated structure was finally leveled with a transparent top lacquer layer 28. In addition, a second transparent embossed lacquer layer 32 was applied to a second transparent carrier film 18, the desired relief structure of the micromirror arrangement 34 was embossed, the embossed structure was provided with an aluminum layer 36 in a grid pattern and the coated structure was finally leveled with a transparent top lacquer layer 38. The top coat layer 38 essentially has has the same refractive index as the embossing lacquer layer 32, so that the micromirrors of the micromirror arrangement 34 do not appear visually in the recessed areas of the aluminum layer 36 due to the lack of refractive index difference between the embossing lacquer layer and the top lacquer layer.

The two layer structures created in this way were then laminated together using a red glazing colored laminating adhesive layer 44. The first carrier film was removed and the resulting structure was transferred to the banknote 10 via an adhesive layer 46 in order to form the security element 12 there.

If the security element 12 created in this way is viewed from the viewing direction 40-A, the viewer looks in the area of the grid elements 52 at the micromirrors of the micromirror arrangement 34 coated with the aluminum layer 36. In the area of the grid spaces 54, the viewer can in principle see the micromirrors of the deeper micromirror arrangement 24 perceive, but their orientation from the viewing direction 40-A is far away from the gloss angle, so that the micromirror arrangement 24 appears inconspicuous and practically does not contribute to the image impression. Overall, the viewer from the viewing direction 40-A essentially sees the silvery, shiny appearance 14-B of the value “10” generated by the micromirror arrangement 34 and the aluminum coating 36.

From the viewing direction 40-B, the micromirrors of the micromirror arrangement 34 in the grid spaces 54 have no optical effect due to the lack of refractive index difference of the lacquer layers 32, 38, so that the viewer 40 there through the translucent flat structure 44 looks through the micromirrors of the micromirror arrangement 24, which are essentially at the gloss angle for the viewing direction 40-B. The color effects of the aluminum coating 26 of the micromirrors and the red glazed flat structure 44 combine to create a shiny red appearance. In the area of the grid elements 52, the micromirrors of the micromirror arrangement 34 are basically perceptible, but their orientation is far away from the gloss angle and they therefore appear inconspicuous from the viewing direction 40-B and practically do not contribute to the image impression. Overall, the viewer from the viewing direction 40-B essentially sees the shiny red appearance 14-B of the curved coat of arms created by the coated micromirror arrangement 24, 26 together with the flat structure 44.

Figure 3 shows some concrete advantageous embodiments of the grid of the color coating 36 of the higher micromirror arrangement 34 in supervision. This shows Fig. 3(a) a grid 50 like it in Fig. 2 is used, in which the grid elements 52 and the grid spaces 54 form a checkerboard pattern. The dimensions of the grid elements and grid spaces are advantageously between 20 x 20 µm ² and 140 x 140 µm ² , the area coverage is 50%. If a different area coverage is to be created, some of the grid elements 52 can be omitted or some of the grid spaces 54 can be occupied with grid elements. In this, but also in the designs described below, the area coverage of the grid with grid elements is preferably between 30% and 70%, in particular between 40% and 60%.

Figure 3(b) shows a grid 50 with alternately arranged strip-shaped grid elements 52 and grid spaces 54. The width of the grid elements and grid spaces are advantageously between 20 µm and 140 µm, the length is arbitrary and can be several millimeters or even a few centimeters. The area coverage can be easily adjusted via the relative width of the grid elements and grid spaces.

The grid elements and grid spaces can also have other polygonal shapes or irregular shapes. Shows as an example Fig. 3(c) an embodiment in which the grid elements 52 and grid spaces 54 of the grid 50 are formed by triangles. At the grid 50 the Fig. 3(d) the grid elements 52 and grid spaces 54 are formed by irregular shapes. The grid elements and/or grid spaces can also form a coherent structure, such as in Fig. 3(d) for the grid spaces 54 shown.

Another variant of a security element 62 according to the invention is shown in Fig. 4 illustrated. The security element 62 is largely similar to that in connection with Fig. 2 The security element 12 described is constructed so that corresponding elements are each provided with the same reference numerals. Like the security element 12, the security element 62 also contains a flat carrier 18 with a multicolored reflective surface area 20, which includes two relief structures in the form of micro-mirror embossings or micro-mirror arrangements 24, 34 and a translucent flat structure 44 arranged between these relief structures. The micromirror arrangements 24, 34 are also in the design of the Fig. 4 each provided with a color coating in the form of a metallization, for example an opaque aluminum layer 26, 36. In this exemplary embodiment, the flat structure 44 is formed by a non-height-structured, continuous, yellow-glazing laminating lacquer layer. The The security element 62 can be produced and transferred to a banknote 10 as described above.

In contrast to the design of the Fig. 2 has the color coating 36 of the design of Fig. 4 a large recess 66, for example in the form of a 5 mm wide and 2 cm long curved strip. In the area of the recess 66, the micromirrors of the micromirror embossing 34 have no optical effect due to the lack of refractive index difference between the lacquer layers 32, 38, so that a viewer there looks through these lacquer layers and the translucent flat structure 44 onto the deeper micromirror arrangement 24 with its aluminum coating 26 . Outside the recess 66, the visual impression of the surface area 20 is determined by the higher micromirror arrangement 34 with its aluminum coating 36.

Specifically, the micromirror embossing 34 can, for example, create a motif in the outer area 64 that appears to bulge out of the plane of the security element 62 and appears shiny silver due to the aluminum coating 36. Inside this motif, a movement effect with a shiny yellow color impression is visible in a partial area 66, which is created by the interaction of the aluminum coating 26 with the yellow glazing laminating lacquer layer 44. As a special feature, the areas of different colors (silvery or shiny yellow) and different effects (three-dimensional motif or movement effect) are precisely matched to one another in a color-to-effect registration.

Figure 5 shows a further exemplary embodiment of a security element 72 according to the invention with a compared to the designs of Figures 2 and 4 modified layer structure. When designing the Fig. 5 became the different layers of the security element 72 are not built on two, but on only one carrier film 18. The security element 72 is designed to be viewed from the side of this carrier film 18.

To produce the security element 72, a transparent embossed lacquer layer 32 was applied to a flat, transparent, colorless carrier film 18, the desired relief structure of the micromirror arrangement 34 was embossed, the embossed structure was provided with a metallization 36 that was only present in certain areas, and the coated structure was finally coated with a transparent top lacquer layer 38 leveled, the refractive index of which corresponds to the refractive index of the embossing lacquer layer 32.

A translucent color layer 74 was applied to the flat surface of the top coat layer 38, which has no height structuring and which forms the translucent colored flat structure of the security element 72.

Finally, a further transparent embossed lacquer layer 22 was applied to the color layer 74, the desired relief structure of the micromirror arrangement 24 was embossed, the embossed structure was coated over the entire surface with a metallization 26, and the coated structure was finally leveled with a further top lacquer layer 28. The layer structure created in this way was transferred to the banknote 10 via an adhesive layer 46 in order to form the security element 72 there. The carrier film 18 can also be removed after the transfer to the banknote 10.

Based on the viewing direction, the micromirror arrangement 24 forms a lower relief structure in the security element 72 and the micromirror arrangement 34 forms a higher relief structure. The color layer 74 lies as a flat structure at a height between the two relief structures 24, 34.

The metallization 36, which is only present in certain areas, can, for example, be in the form of a with reference to Figures 2 and 3 described grid, or as a layer with large recesses, as in Fig. 4 described. Depending on the specific design of the metallization 36 present in certain areas, the different visual effects described above of a binary color and effect change or a color-to-effect registration can arise. In all designs, the color effect of the higher relief structure 34 is determined by the metallization 36, so that, for example, a silvery, shiny color effect results. The color effect of the deeper relief structure 24 results from the interaction of the translucent color layer 74 and the continuous metallization 26, so that depending on the color of the color layer, for example, a colored, for example yellow, red, blue or green, shiny color effect results.

Another embodiment of the invention is in Fig. 6 illustrated. The security element 82 of the Fig. 6 contains an internal carrier film 18, on the first main surface of which a translucent color layer 84 has been applied, which has no height structuring and which forms the translucent colored flat structure of the security element 82. A first transparent embossed lacquer layer 22 was applied to the color layer 84, the desired relief structure of the micromirror arrangement 24 was embossed, the embossed structure was coated over the entire surface with a metallization 26 and the coated structure was finally leveled with a top lacquer layer 28.

A second transparent embossing lacquer layer 32 was applied to the opposite main surface of the carrier film 18 and the desired relief structure of the micromirror arrangement 34 was embossed. The relief structure 34 is provided with a metallization 36 that is only present in certain areas; in addition, a translucent color 86 can be provided congruently with the metallization 36, which, like the metallization 36, follows the height of the relief structure 34. The translucent color 86, together with the metallization 36, forms a color coating 88 that follows the height of the relief structure 34. The coated relief structure 34, 88 was finally leveled with a transparent top coat layer 38, the refractive index of which corresponds to the refractive index of the embossed lacquer layer 32.

The layer structure created in this way was transferred to the banknote 10 via an adhesive layer 46 in order to form the security element 82 there. Based on the viewing direction from the side of the relief structure, which is only partially provided with a color coating, the micromirror arrangement 24 forms a lower relief structure in the security element 82 and the micromirror arrangement 34 forms a higher relief structure. The color layer 84 lies as a flat structure at a height level between the two relief structures 24, 34.

Here too, different visual effects result depending on the specific design of the metallization 36 present in certain areas and the translucent color 86. In all designs, however, the color effect of the higher-lying relief structure 34 results from the interaction of the metallization 36 with the glazing color 86 and is, for example, shiny blue in the case of a blue-glazing color 86, while the color effect of the lower-lying relief structure 24 is due to the interaction of the glazing Color layer 74 and the continuous metallization 26 results and, for example, with a red glazing color layer 74 is shiny red.

Reference symbol list

10

Banknote

12

Security element

14-A

bulging motif "10"

14-B

bulging motif “coat of arms”

16

Tilting direction

18

carrier

20

reflective surface area

22

first layer of embossing varnish

24

Micromirror arrangement

26

first color coating

28

transparent top coat layer

32

second layer of embossing varnish

34

Micromirror arrangement

36

second color coating

38

Top coat

40

viewer

40-A, 40-B

Viewing positions

44

translucent flat structure

46

adhesive layer

50

grid

52

Grid elements

54

Grid spaces

62

Security element

64

Outdoor area

66

recess

72

Security element

74

glazing color layer

82

Security element

84

glazing color layer

86

glazing color

88

height-structured color coating

Claims (16)

1. Optically variable security element (12) for securing valuable objects, the surface extension of which defines a z-axis perpendicular thereto, comprising a polychromatic reflective surface region (20),

   - the multi-colored reflective surface region (20) containing two relief structures (24, 34) which are arranged at different vertical levels in the z-direction and form a lower and an upper relief structure,

   - the lower relief structure (24) being provided with a first color coating (26) following the relief profile and the upper relief structure (34) being provided with a second color coating (36) following the relief profile,

   - a translucent colored structure (44) being arranged at a vertical level between the two relief structures (24, 34) in the z-direction,

   - the two relief structures (24, 34) and the colored structure (44) overlapping in an overlap region, and

   - the second color coating (36) of the upper relief structure (34) having at least one recess (54, 66) in the overlap region, in which the lower relief structure (24) is visible with the combined color effect of the colored structure (44) and the first color coating (26) when the security element is viewed,

   characterized in that
   the colored structure (44) is a colored planar structure (44), and the upper relief structure (34) and/or the lower relief structure (24) are formed by micromirror arrangements with directed micro mirrors.
2. Security element (12) according to claim 1, characterized in that the planar structure (44) is formed by a laminating lacquer layer, a primer layer or a printed color layer.
3. Security element (12) according to either claim 1 or claim 2,
   characterized in that the planar structure (44) contains coloring pigments and/or a dye as colorants.
4. Security element (12) according to at least one of claims 1 to 3,
   characterized in that in the overlap region, the second color coating (36) of the upper relief structure (34) is formed as a regular or irregular grid having grid elements (52) and grid spaces (54), the dimensions of the grid elements (52) and/or grid spaces (54) being below 140 µm at least in one direction, preferably that the dimensions of the grid elements (52) and/or grid spaces (54) are below 140 µm, preferably between 20 µm and 100 µm, in particular between 20 µm and 60 µm in one or both lateral directions.
5. Security element (12) according to claim 4, characterized in that the grid elements (52) and grid spaces (54) of the grid have the same shape and preferably also the same size, and/or in that the coverage of the grid by the grid elements (52) is between 30% and 70%, preferably between 40% and 60%, in particular approximately 50%.
6. Security element (12, 62) according to any of claims 1 to 5,
   characterized in that in the overlap region, the second color coating (36) of the upper relief structure (34) contains portions (64) which have lateral dimensions of more than 140 µm, and/or in that the second color coating (36) of the upper relief structure (34) is generated in the overlap region with recesses (66) having lateral dimensions of more than 140 µm.
7. Security element (12) according to any of claims 1 to 6,
   characterized in that in the overlap region, the first color coating (26) of the lower relief structure (24) is opaque and/or in that the first color coating (26) of the lower relief structure (24) is formed over the entire surface in the overlap region.
8. Security element (12) according to at least one of claims 1 to 7,
   characterized in that the first and/or the second color coating (26, 36) are reflective color coatings, and are in particular formed by metallizations, thin-film structures, glazed colors deposited by a metallization, by luminescent colors having a metallic reflective coating, by structural colors and/or by nanoparticle colors.
9. Security element (12) according to at least one of claims 1 to 8,
   characterized in that the directed micromirrors are non-diffractively acting mirrors, preferably planar mirrors, concave mirrors and/or Fresnel-like mirrors.
10. Security element (12) according to at least one of claims 1 to 9,
    characterized in that the orientation of the micromirrors of the upper relief structure (34) and/or of the lower relief structure (24) varies in a location-dependent manner in order to generate a respectively predetermined motif, in particular a motif that appears three dimensional or a moving motif.
11. Data carrier (10) having an optically variable security element (12) according to at least one of claims 1 to 10, wherein the lower relief structure (24) is located closer to a surface of the data carrier and the upper relief structure (34) is located further away from the aforementioned surface of the data carrier.
12. The data carrier (10) according to claim 11, characterized in that the security element (12) is arranged in an opaque region of the data carrier (10).
13. Method for producing an optically variable security element (12), preferably according to any of claims 1 to 10, in which

    - a carrier (18) is provided, the surface extension of which defines a plane and a z-axis perpendicular thereto,

    - the carrier (18) is provided with a polychromatic reflective surface region (20) containing two relief structures (24, 34) which are arranged at different vertical levels in the z-direction and form an upper and a lower relief structure,

    - the lower relief structure (24) is provided with a first color coating (26) following the relief profile and the upper relief structure (34) is provided with a second color coating (36) following the relief profile,

    - a translucent colored structure (44) is arranged at a vertical level between the two relief structures in the z-direction,

    - the two relief structures (24, 34) and the colored structure (44) are designed to overlap in an overlap region, and

    - the second color coating (36) of the upper relief structure (34) in the overlap region is formed with at least one recess, in which the lower relief structure (24) is visible with the combined color effect of the colored structure (44) and the first color coating (26) when the security element (12) is viewed,

    characterized in that

    the colored structure (44) is a colored planar structure (44), and

    the upper relief structure (34) and/or the lower relief structure (24) are formed by micromirror arrangements with directed micromirrors.
14. Method according to claim 13, characterized in that two layer structures are produced separately, in which the aforementioned relief structures are produced on separate carriers (18) and are provided with the relevant color coating following the relief profile, and in that the two produced layer structures are laminated together via a translucent colored laminating lacquer layer which, in the laminated state, forms the planar structure (44) of the security element (12).
15. Method according to claim 13, characterized in that the upper relief structure (34)having the second color coating (36) is first produced on a carrier (18), the coated relief structure is leveled with a cover layer (38), a translucent, non-vertically structured color layer is applied to the cover layer (38), which layer forms the planar structure (44) of the security element, and in that the lower relief structure (24) having the first color coating (26) is produced on the translucent color layer.
16. Method according to claim 13, characterized in that a carrier (18) is provided with a translucent, non-vertically structured color layer (84) on one of its main surfaces, in that the aforementioned relief structures are applied to the opposite main surfaces of the color-coated carrier (18, 84), so that the translucent color layer (84) forms a planar structure between the relief structures, and in that the relief structures (24, 34) are provided with the relevant first or second color coating (26, 36).

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