DE102019003945A1 - Optically variable security element with multicolored reflective surface area - Google Patents

Abstract

The invention relates to an optically variable security element (12) for securing objects of value, the extent of which defines a z-axis perpendicular to it, with a multicolored reflective surface area, the multicolored reflective surface area containing two optically variable reflection structures (44, 46; 32) which are arranged in the z-direction at different heights and which produce a different color impression in reflection, - the higher-lying reflection structure is formed by a relief structure (44) provided with a color coating (46), - the lower-lying reflection structure is formed by a layer (30) is formed with platelet-shaped, reflective effect pigments (32) which are aligned three-dimensionally, - the two reflection structures overlap in an overlap area and the color coating (46) of the higher-lying reflection structure has at least one recess (54; 66) in the overlap area , in which the deeper reflection structure (32) appears when viewed. The invention also includes a data carrier with such a security element and an associated manufacturing method.

Description

The invention relates to an optically variable security element with a multicolored reflective surface area for protecting objects of value. The invention also relates to a method for manufacturing such a security element and a data carrier equipped with such a security element.

Data carriers, such as value or identity documents, but also other objects of value such as branded items, are often provided with security elements for protection that allow the authenticity of the data carrier to be checked and at the same time serve as protection against unauthorized reproduction. The security elements can for example be in the form of a security thread embedded in a bank note, a cover film for a bank note 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 value document.

Security elements with a viewing angle-dependent or three-dimensional appearance play a special role in safeguarding authenticity, since these cannot be reproduced even with the most modern copiers. For this purpose, the security elements are equipped with optically variable elements which convey a different image impression to the viewer from 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, for example, movement effects, pump effects, depth effects or flip effects are described as optically variable effects, which are implemented with the aid of holograms, microlenses or micromirrors.

From the pamphlet WO 2015/078572 A1 a security element with magnetically alignable magnetic pigments is known. The pamphlet EP 3 254 863 A1 relates to a security element with a printed color layer which, in addition to first pigments, also comprises second pigments, which are designed as magnetic pigments.

Proceeding from this, the invention is based on the object of further increasing the counterfeit security and the visual attractiveness of generic optically variable security elements and in particular providing optically variable security elements with two or more different appearances or effects in different colors.

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

In order to achieve the stated object, the invention contains an optically variable security element with a multicolored reflective surface area which can be used in particular to secure objects of value.

The area of the security element defines a plane and a z-axis perpendicular to it. According to the invention, the multicolored reflective surface area contains two optically variable reflection structures which are arranged at different height levels in the z-direction and which produce a different color impression in reflection.

The higher-lying reflection structure is formed by a relief structure provided with a colored coating, while the lower-lying reflection structure is formed by a layer with platelet-shaped, reflective effect pigments which are spatially aligned.

The two reflection structures overlap in an overlap area and the color coating of the higher-lying reflection structure has at least one recess in the overlap area, in which the lower-lying reflection structure appears when the security element is viewed.

The mentioned overlap can be partial or complete, so one of the reflection structures can also completely cover the other reflection structure and the two reflection structures can even be designed to be congruent. The mentioned overlap relates to the relative lateral position of the reflection structures in the plane defined by the surface extension of the security element.

The terms “lying higher” and “lying deeper” relate to viewing the security element from the positive z-direction. It goes without saying that an applied security element in transparent areas or window areas of a data carrier can typically also be viewed from the rear, that is to say from the negative z-direction. The viewer then first looks at the layer with the platelet-shaped, reflective effect pigments and, in areas in which this layer is translucent or has recesses, also at the relief structure provided with the color coating.

The platelet-shaped effect pigments are particularly advantageously formed by platelet-shaped magnetic pigments that can be aligned by a magnetic field, but they can also be platelet-shaped effect pigments that can be aligned by other fields, for example electrical fields. This alignability in magnetic or other fields is a property of the effect pigments themselves. For example, due to their magnetic properties, magnetic pigments can be influenced by an external magnetic field and can also be aligned in a mobile state. In the finished security element, the effect pigments are already aligned and immobilized, that is, their alignment is fixed. The aligned effect pigments not only lie flat in the plane of the surface area, but are at least partially tilted towards this plane and are therefore spatially aligned. The alignment is determined in particular by the angle of inclination and azimuth angle of the effect pigments. Due to the alignment with the aid of an external field, the alignment of the individual effect pigments cannot be freely selected. Rather, the orientation of the effect pigments is not individual and, in particular, is field-dependent. The field dependency requires, for example, that an alignment difference between adjacent effect pigments corresponds to the maximum possible field change at this distance, that is to say is rather small. The maximum alignment difference of jointly aligned, adjacent effect pigments is less than 30 degrees, preferably less than 20 degrees, for both angles.

Metallized pigments, in particular aluminum- or silver-coated pigments, are preferably used as effect pigments. Pigments with a thin-film coating, especially color-shifting pigments or aluminum pigments with a coloring coating produced by wet-chemical precipitation processes, are also suitable. In addition, reflective metal pigments, preferably aluminum pigments, with a translucent color coating can also be used, or pigments with a color coating formed by structural colors, in particular by nano and binary structures.

The flake-form effect pigments advantageously have a ratio of the largest to the smallest diameter (diameter-to-thickness ratio) that is more than 5: 1, preferably more than 10: 1, and particularly preferably more than 15: 1 or even more than 50: 1 amounts. The largest diameter of the flake-form effect pigments is preferably between 5 μm and 35 μm, preferably between 15 μm and 25 μm or between 8 μm and 12 μm. For example, those in the publications come as flake-form effect pigments EP 1 689 586 B1 , WO 2010/069823 A1 and WO 2013/090983 A1 described particles and pigments in question.

The effect pigments are expediently in a printing layer with a transparent or translucent binder. The binding agent can also be colored in order to produce an additional color effect in the security element.

In a preferred configuration, the relief structure of the higher-lying reflection structure is formed by a micromirror arrangement with directional micromirrors, in particular with plane mirrors, concave mirrors and / or Fresnel-like mirrors. The orientation (angle of inclination and azimuth angle) of the micromirrors of the relief structure can be freely selected for each micromirror. The micromirrors are aligned independently of one another, in particular aligned by means of embossing. A maximum (or mean) alignment difference between neighboring micromirrors is - for one or both angles - greater than 90 degrees. Neighboring micromirrors of the relief structure differ in their alignment, in particular in the angle of inclination and in the azimuth angle. The lateral dimensions of the micromirrors are advantageously below 20 μm, preferably below 10 μm. In principle, however, other relief structures, in particular embossed Fresnel lenses, concave mirrors, hologram structures, nanostructures or diffractive blazed gratings can also be used.

The relief structure of the higher-lying reflection structure is advantageously shaped in a transparent or translucent embossed lacquer layer, in particular embossed into this embossed lacquer layer. The embossing lacquer layer can also be colored in order to produce an additional color effect in the security element.

In an advantageous variant of the invention, the color coating of the higher-lying reflection structure is designed as a regular or irregular grid with grid elements and grid spaces. The grid spaces represent the above-mentioned gaps. The dimensions of the grid elements and / or grid spaces in this variant are at least in one direction below 140 μm. Preferably, the dimensions of the grid elements and / or grid spaces are even in one or both lateral directions below 140 μm, 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 spacings and / or sizes and / or shapes. The area coverage of the grid by the grid elements is advantageously between 30% and 70%, preferably between 40% and 60%, in particular around 50%.

In a further variant of the invention, the color coating is applied alternatively or in addition to the grid mentioned, advantageously in partial areas that have lateral dimensions of more than 140 μm, and / or the color coating is produced with cutouts that have lateral dimensions of more than 140 μm. In the first-mentioned case, the surface areas surrounding the applied partial areas represented the above-mentioned recesses of the color coating. 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 color coating of the relief structure mentioned is formed in an advantageous configuration by means of translucent colors. Metallizations, for example made of aluminum, silver or an alloy such as copper and aluminum, can also be used, as well as thin-film structures, in particular color-shifting thin-film structures, gold-blue or silicon-aluminum thin layers. The color coating can also be formed by translucent colors with a deposited metallic mirror coating, for example made of aluminum. The color coating can represent a translucent image 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 used as color coatings. The color coating can also be formed by structural colors, in particular by nano and binary structures, which are embossed on or in the micromirrors of a micromirror arrangement. Finally, nanoparticle inks can also be used as color coatings, such as gold-blue particles, various effect pigments, color-changing pigments or super silver.

The different height levels in which the two reflection structures are arranged advantageously have a spacing between 5 μm and 100 μm, preferably between 10 μm and 50 μm, in the z direction. The small vertical distance between the two reflection structures cannot be perceived when viewing the security element. The height level of a relief structure is given by the base area of the relief structure, for example a micromirror embossing. Similarly, the height level of aligned effect pigments is given by the middle position of the pigments tilted relative to the plane of the surface area. However, the exact definition of the height level is usually not important, since different height levels can be implemented in a simple manner, for example, in that the two reflection structures are on opposite sides of a carrier film, or that the two reflection structures are superimposed on the same side of a carrier film .

The two reflection structures of the reflective surface area 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 reflection structures can vary in particular with regard to shape (for example head, apple or tails), movement (static too moved or moved too static, with linear, rotating and / or pumping movement) and / or dimensionality (2D to 3D, or different three-dimensional with positive or negative arched appearance or floating in front of or behind a plane) of the motif.

In an advantageous embodiment, it is provided that the higher-lying reflective structure generates a first motif with a first color impression that is visible from a first viewing angle range and the lower-lying reflection 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 adjoin one another or be separated only by an angular distance of a few degrees, so that the associated image impressions for the viewer jump around almost seamlessly.

The higher-lying reflection structure can also generate a first movement motif with a first color impression and the lower-lying reflection structure can generate a second movement motif with a second, different color impression, the first and second movement motifs moving offset from one another or moving against one another and moving when the security element is tilted while doing so, cross in an overlapping position in which both motifs are visible.

The two reflection structures can also generate motifs or motifs of movement that are visible at the same time in the same surface area, that is to say have at least partially overlapping viewing angle areas. Since the vertical distance between the two reflection structures is very small and is well below the resolution limit of the naked eye, the appearances produced by the two reflection structures appear to be at the same location for a viewer at the same time.

• - 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 variants named below have proven to be particularly attractive from a visual point of view:

• - A binary motif flip between curved and / or three-dimensional appearing 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, and a second viewing angle range from -5 ° to -20 °. The first and second motifs can also be identical, so that a pure binary color change results.
• - Pump or running effects with different colors that cross locally, for example run 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, opposite movement motif, conversely, extends from + 20 ° to -20 °. In the case of staggered motion motifs, one motif runs from -20 ° to + 10 °, for example, the other from -10 ° to + 20 °.
• - A binary motif flip in which the curved and / or three-dimensional appearing different colored motifs lie one inside the other and / or overlap each other. When tilting, a simultaneous color change of the inner and outer motif or the overlapping motif parts takes place.

In an advantageous further development of the invention, a translucent color layer or an image of several translucent colors can be present between the two reflection structures in order to produce an additional color effect in the security element. The translucent colors do not have to be applied directly on / above the reflective effect pigments; instead, a translucent color can be introduced at any point between the two reflection structures. In other configurations, a translucent color can also be mixed into another layer, for example by using a colored UV lacquer for the said embossing lacquer layer, a colored film or a colored binder for the printing layer of the effect pigments.

The security element described can also be equipped with colorless or colored negative identifiers. For this purpose, it can be provided in particular that the overlap area contains partial areas with negative identification in which the color coating of the higher-lying reflective structure and the effect pigments of the lower-lying reflective structure are left out.

If the effect pigments are present in a printing layer, the entire printing layer can be left out in certain areas in order to generate a negative identifier. Alternatively, the printing layer can also have areas in which only the binder is present, but the effect pigments have been removed, for example by exposure to a laser, or their visual effect has been deactivated.

The invention also contains a data carrier with an optically variable security element of the type described. In an advantageous embodiment, the data carrier contains a carrier with opposite main surfaces, on each of which one of the two optically variable reflection structures is arranged. The carrier is transparent in the overlap area or contains a transparent see-through window. For example, the carrier can be formed by a transparent polymer substrate, or by a paper substrate or hybrid substrate with a transparent window area. Alternatively, both optically variable reflection structures can also be arranged one above the other on a main surface of a 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 mit zwei optisch variablen Reflexionsstrukturen ausgebildet wird, die in z-Richtung in unterschiedlichen Höhenstufen angeordnet werden, und die in Reflexion einen unterschiedlichen Farbeindruck erzeugen,
• - die höher liegende Reflexionsstruktur durch eine mit einer Farbbeschichtung versehene Reliefstruktur gebildet wird,
• - die tiefer liegende Reflexionsstruktur durch eine Schicht mit plättchenförmigen, reflektierenden Effektpigmenten gebildet wird, welche räumlich ausgerichtet werden, und
• - die beiden Reflexionsstrukturen in einem Überlappungsbereich überlappend ausgebildet werden und die Farbbeschichtung der höher liegenden Reflexionsstruktur in dem Überlappungsbereich mit zumindest einer Aussparung ausgebildet wird, in der bei Betrachtung des Sicherheitselements die tiefer liegende Reflexionsstruktur in Erscheinung tritt.

Finally, the invention also includes 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 area of which defines a plane and a z-axis perpendicular to it,
• - The carrier is provided with a multicolored reflective surface area which is formed with two optically variable reflection structures which are arranged in the z-direction at different height levels and which produce a different color impression in reflection,
• - the higher-lying reflective structure is formed by a relief structure provided with a color coating,
• - The deeper-lying reflection structure is formed by a layer with platelet-shaped, reflective effect pigments, which are spatially aligned, and
• - The two reflection structures are designed to overlap in an overlap area and the color coating of the higher-lying reflective structure is formed in the overlap area with at least one cutout in which the lower-lying reflective structure appears when the security element is viewed.

To form the deeper reflection structure, it is advantageous to apply a printing ink with a binding agent and with effect pigments that can be aligned magnetically or by other fields; the effect pigments are aligned with an external field, in particular an external magnetic field, to the desired spatial alignment when the binding agent is still in a liquid state to generate, and the binder is solidified in order to permanently fix the orientation of the effect pigments. Solidifying the printing ink can comprise an active step of hardening, for example by means of heating or irradiation. The printing ink can optionally additionally comprise volatile components, but is preferably (essentially) free of volatile components.

To form the higher-lying reflective structure, an embossing lacquer layer is advantageously applied to a carrier film, embossed with the desired relief structure and then provided with the color coating in areas. A further lacquer coating is expediently applied to the embossed and coated embossing lacquer layer, the refractive index of which does not deviate by more than 0.25 from the refractive index of the embossing lacquer layer. In an advantageous variant of the method, the sequence of layers produced in this way is applied, at least partially overlapping, to the printing layer with the effect pigments or to a target substrate. After the application, the carrier film used for the production can be peeled off or, for example in the case of a thin, transparent carrier film, also remain in the security element.

Further exemplary embodiments as well as advantages of the invention are explained below with reference to the figures, the representation of which is true to scale and proportions has been dispensed with in order to increase the clarity.

• 1 eine schematische Darstellung einer Banknote mit einem erfindungsgemäßen optisch variablen Sicherheitselement,
• 2 schematisch einen Ausschnitt des Sicherheitselements der 1 im Querschnitt,
• 3 in (a) bis (d) einige konkrete vorteilhafte Ausgestaltungen des Rasters der Farbbeschichtung der Mikrospiegelprägung in Aufsicht,
• 4 als weiteres Ausführungsbeispiel der Erfindung eine Abwandlung der Ausgestaltung der 2,
• 5 eine weitere Variante eines erfindungsgemäßen Sicherheitselements im Querschnitt, und
• 6 in (a) bis (c) einige vorteilhafte Varianten von erfindungsgemäßen Datenträgern mit unterschiedlicher Schichtenfolge.

Show it:

• 1 a schematic representation of a bank note with an optically variable security element according to the invention,
• 2 schematically a section of the security element of 1 in cross section,
• 3 in (a) to (d) some concrete advantageous configurations of the grid of the color coating of the micromirror embossing in plan view,
• 4th as a further embodiment of the invention, a modification of the configuration of the 2 ,
• 5 a further variant of a security element according to the invention in cross section, and
• 6th in (a) to (c) some advantageous variants of data carriers according to the invention with different layer sequences.

The invention will now be explained using the example of security elements for bank notes. 1 shows a schematic representation of a bank note 10 with an optically variable security element according to the invention 12th .

The security element 12th shows two security features with different visual appearance and movement behavior in the same area. As in the detail section 20th the 1 shown schematically shows a first security feature 14th of the security element 12th a metallic, three-dimensional appearance with a series of larger rings 22nd over a number of corresponding smaller rings 24 seems to float. When tilting the safety element 12th the larger and smaller rings move 22nd , 24 for the viewer against each other and thus create a striking three-dimensional movement feature.

At the same time, the security element is in the same surface area 12th a second security feature 16 to recognize this in the form of a color-changing zigzag pattern 26th is trained. The lines of the zigzag pattern 26th show an outwardly curved three-dimensional appearance, and the color impression of the pattern changes 26th Depending on the viewing angle, from green when viewed perpendicularly to blue when viewed from an angle.

The particular structure of optically variable security elements according to the invention will now be illustrated with the aid of the design of 2 explained in more detail that a section of the security element 12th the 1 shows schematically in cross section.

The security element 12th contains a flat carrier 18th whose surface area defines an xy plane and a z-axis perpendicular to it. In the exemplary embodiment, the carrier 18th the polymer or paper substrate of the banknote 10 represent.

To generate the second security feature 16 contains the security element 12th a print layer 30th with magnetic in the form of the convex zigzag pattern 26th aligned, color-shifting, platelet-shaped magnetic pigments 32 . This was done on the carrier 18th a print layer 30th with magnetically alignable magnetic pigments 32 printed on, and the magnetic pigments 32 were in the still moist state of the binder 34 with the help of an external magnetic field aligned in the shape of the desired motif. Then the binder 34 solidified, for example by exposure to UV, in order to align the magnetic pigments 32 to fix permanently. The magnetic pigments with a color shift effect can be, for example, magnetic interference pigments, as shown in FIG EP 1 366 380 A2 and are offered by Sicpa Holding SA, for example, under the names OVMI Gold / Green 5 SK 1001 S, OVMI Green / Blue 5 SK 5001 S and OVMI Magenta / Green 5 SK 3001 S.

To generate the first security feature 14th is above the print layer 30th an embossed layer 40 arranged that an embossing lacquer layer 42 with a micro-mirror embossing 44 includes. The micro mirror embossing 44 is with a color coating 46 , for example, a metal layer which is only present in certain areas and which is in its recesses 54 the view of the print layer 30th releases. The micro mirror embossing 44 is formed from a large number of micromirrors inclined with respect to the xy plane with a typical edge length of approximately 10 μm. The local angles of inclination of the micromirrors are chosen so that the relief structure formed by the micromirrors together with the color coating 46 a desired visual appearance, for example the representation of the two rows of nested rings 22nd , 24 the 1 generated.

For producing the embossing layer 40 can for example be an embossing lacquer layer 42 applied to a carrier film with the desired micromirror relief structure 44 embossed and then with the color coating in areas 46 be provided. The coated embossing lacquer layer 44 , 46 is then coated with a varnish 48 provided whose refractive index is essentially the refractive index of the embossing lacquer layer 42 corresponds, and the layer sequence produced in this way is finally at least partially overlapping on the printing layer 30th upset. The paint coating 48 themselves have adhesive properties or an additional adhesive layer can be used. After application, the carrier film used in production can be peeled off the embossing lacquer layer or, for example in the case of a thin, transparent carrier film, can also remain on the banknote.

After such a superposition of the printing layer 30th and the embossing layer 40 forms the coated micromirror embossing 44 , 46 the embossing layer 40 in the security element 12th a higher-lying reflective structure, while the spatially aligned magnetic pigments 32 the print layer 30th form a deeper reflection structure. Together form the layers 30th , 40 the multicolored reflective surface area of the security element 12th .

What is essential for the deeper reflection structure is that the platelet-shaped magnetic pigments 32 due to the magnetic alignment not only flat in the plane of the printing layer 30th but are locally tilted to different degrees against this plane and are therefore spatially aligned. In this way, the magnetic pigments reflect 32 in different spatial directions with different strengths and thus create the special, for example three-dimensional and / or dynamic appearance of the zigzag pattern 26th .

What is essential with the higher-lying reflective structure is that the color coating 46 with cutouts 54 is provided to a viewer 56 despite the continuous micro-mirror embossing 44 in some areas a view of the underlying magnetic pigments 32 to enable.

The color coating is specific 46 in the design of 2 in the form of a regular grid 50 from grid elements 52 and grid spaces 54 educated. The grid elements 52 and grid spaces 54 form, for example, a checkerboard pattern in which each field, i.e. each grid element 52 and every grid space 54 , has a dimension of 100 µm x 100 µm. Because the individual micromirrors of the micromirror imprint 44 are usually significantly smaller, for example have an edge length of only 10 µm, the grid falls 50 the color coating 46 , unlike in the simplified schematic representation of the 2 , generally not with the grid of the micromirrors.

While in the field of grid elements 52 the reflective effect of the color coating 46 dominates, unfold the micromirrors of the micromirror embossing 44 in the grid spaces 54 due to the lack of refractive index difference between the lacquer layers 42 , 48 no visual effect, so the viewer 56 there on the magnetic pigments 32 the print layer 30th looks. In this way, the security element is in the same surface area 12th both security features 14th , 16 visible to the viewer. As the thickness of the print layer 30th and the embossing layer 40 are in the range of a few micrometers or a few tens of micrometers, it is for the viewer 56 it cannot be seen that the two optically variable reflection structures are actually arranged in the z-direction at different height levels - they rather seem despite their different visual appearance to be present in the same place at the same time.

In the exemplary embodiment, the grid elements 52 and the grid spaces 54 the same dimensions in each case, so that the area coverage of the grid is 50%. Depending on the desired relative brightness of the two appearances and the reflective properties of the color coating 46 and the magnetic pigments 32 However, there can also be other surface coverages of the grid 50 to offer. Basically, the area of the grid is covered by grid elements 52 preferably between 30% and 70%, in particular between 40% and 60%.

Is the security element 12th the 1 and 2 in a transparent area or a window area of the banknote 10 arranged, it can also be viewed from the rear. Viewer, observer 56 then first look at the print layer 30th with the aligned magnetic pigments 32 so that the security feature 16 in the form of the color-changing zigzag pattern 26th can also be clearly seen from the rear. The first security feature 14th can also be seen, but appears weaker from the rear because the viewer is also in the areas without magnetic pigments 32 through the binder 34 the print layer 30th looks through. The metallic, three-dimensional appearance of the micro-mirror embossing 44 also appears three-dimensionally inverted from the rear, so that the smaller rings in the exemplary embodiment 24 over the larger rings 22nd seem to float.

3 shows some concrete advantageous embodiments of the grid of the color coating 46 the micro-mirror embossing 44 under supervision. It shows 3 (a) a grid 50 like it in 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 × 20 μm ² and 140 × 140 μm ² , the area coverage is 50%. If a different area coverage is to be generated, some of the grid elements can be used 52 omitted or some of the grid spaces 54 can be covered with additional grid elements.

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 is 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 easily be set via the relative width of the grid elements and grid spaces, and is preferably between 30% and 70%, in particular between 40% and 60%.

The grid elements and grid spaces can also have other polygonal shapes or irregular shapes. Exemplary shows 3 (c) an embodiment in which the grid elements 52 and grid spaces 54 of the grid 50 are formed by triangles. With the grid 50 the 3 (d) are the grid elements 52 and grid spaces 54 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. Here, too, the area coverage with grid elements is preferably between 30% and 70%, in particular between 40% and 60%.

4th shows a modification of the embodiment of 2 , at which the angle of inclination of the micromirrors of the micromirror embossing 44 and the magnetic alignment of the magnetic pigments 32 are chosen so that the appearances generated by the two reflection structures are visible in different, non-overlapping viewing angle areas and thus a binary change in color and effect when the security element is tilted 12th produce.

Specifically, the micromirrors are the micromirror imprint 44 aligned for this purpose, for example, in such a way that the appearance produced by the micromirrors, for example a curved representation with a metallic effect, is in a plane normal to the surface N related viewing angle range from + 5 ° to + 20 ° (viewing direction 58-A ) becomes visible. The magnetic pigments 32 on the other hand, were aligned by an external magnetic field in such a way that they create a running effect that can be seen in a viewing angle range of -5 ° to -20 ° in relation to the surface normal (viewing position 58-B ) becomes visible.

From the viewing direction 58-A the viewer looks in the area of the grid elements 52 on the coated micromirrors of the micromirror embossing 44 . In the area of the grid spaces 54 the viewer can basically use the magnetic pigments 32 the print layer 30th perceive, but their orientation is from the viewing direction 58-A far from the glancing angle. The magnetic pigments 32 therefore appear inconspicuous and, since they are heavily outshone by the micromirrors that are essentially at the glancing angle, practically do not contribute to the image impression. Overall, it appears to the viewer from the viewing direction 58-A thus essentially that of the micro-mirror embossing 44 generated vault representation.

From the viewing direction 58-B unfold the micromirrors of the micromirror embossing 44 in the grid spaces 54 due to the lack of refractive index difference between the lacquer layers 42 , 48 no optical effect, so that the viewer is there in the viewing direction 58-B Magnetic pigments essentially in the glancing angle 32 looks. In the area of the grid elements 52 are the micromirrors of the micromirror imprint 44 although basically perceptible, their orientation is from the viewing direction 58-B far from the glancing angle. They therefore appear inconspicuous and wear because they are affected by the magnetic pigments in the glancing angle 32 are strongly outshone, practically does not contribute to the image impression. Overall, it appears to the viewer from the viewing direction 58-B thus essentially that of the Magnetpimenten 32 generated, optically variable running effect.

When tilting the safety element 12th its appearance suddenly jumps between the appearance of the metallic arching and the appearance of the optically variable running effect at a certain viewing angle. The change of the motif and the color effect takes place simultaneously and without an intermediate or transition 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, and therefore represents a binary change in color and effect .

Another variant of a security element according to the invention 62 is in 5 illustrated. The security element 62 is largely similar to that related to 2 described security element 12th constructed so that corresponding elements are provided with the same reference numerals. Like the security element 12th also contains the security element 62 a flat carrier 18th , a print layer 30th with aligned, color-shifting, platelet-shaped magnetic pigments 32 and one over the print layer 30th arranged embossing layer 40 with one in an embossing lacquer layer 42 incorporated micro-mirror embossing 44 with a color coating present in certain areas 46 is provided.

In contrast to the design of the 2 exhibits the color coating 46 the design of 5 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 unfold the micromirrors of the micromirror embossing 44 due to the lack of a difference in refractive index between the layers of lacquer 42 , 48 no optical effect, so that a viewer there on the deeper-lying magnetic pigments 32 the print layer 30th looks. Outside 64 outside the recess 66 becomes the visual impression of the security element 62 on the other hand, from the higher-lying micro-mirror imprint 44 and their color coating 46 certainly.

Specifically, the micro-mirror embossing can 44 for example outdoors 64 a seemingly out of the level of the security element 62 bulging motif 64 produce that appears in a first color. Inside the subject 64 is in a sub-area 66 a movement effect visible in a second color, that of the aligned magnetic pigments 32 is produced. For example, a light bar can appear when the security element is tilted 62 along the sub-area 66 Move up and down and create a so-called rolling bar effect. Because the rolling bar effect is in the recess 66 the color coating 46 is visible, the areas of different colors (first and second colors) and different effects (three-dimensional motif or running bar) appear to be exactly matched to one another.

There are numerous degrees of freedom for the layer structure of the security elements and the layer structure of data carriers with such security elements. The possibility has already been described of applying the magnetic pigments in a print layer to the paper or polymer substrate of a document of value and of applying a security film with a partially coated micromirror embossing over the print.

Further advantageous variants are in 6th illustrated, the embossed layer 40 can be designed in all variants with or without a carrier film and can be in the form of a strip or patch, for example.

First shows 6 (a) a polymer banknote 70 with a transparent polymer substrate 72 where the print layer 30th and the embossing layer 40 are arranged on opposite sides at least partially overlapping one another.

The design of the 6 (b) shows a paper banknote 80 with a paper substrate 82 with window 84 . The print layer 30th and the embossing layer 40 are at least partially overlapping on opposite sides of the window 84 arranged. Magnetic pigments could also be used inside the window 32 exist as in 6 (b) illustrated.

6 (c) showed a hybrid banknote 90 with a foil / paper / foil hybrid substrate 92 with a window 94 in the paper core 96 . The print layer 30th and the embossing layer 40 are on opposite sides of the hybrid substrate 92 arranged and overlap each other in the area of the window 94 at least partially. The embossing layer 40 can, as in 6 (c) shown outside on the composite of the Hybrid substrate 92 be applied, but it can, for example, also between the paper core 96 and one of the foil layers 98 are present and thus represent a particularly strongly protected, internal security feature.

Another variant of the invention consists in not applying the embossed layer in the form of a security film, but rather the embossed structure 44 to be introduced directly into the polymer substrate of a work document. Then the print layer can then 30th be printed overlapping.

List of reference symbols

10

Banknote

12

Security element

14.16

Security features

18th

carrier

20th

Detail section

22, 24

larger or smaller rings

26th

Zigzag pattern

30th

Print layer

32

Magnetic pigments

34

binder

40

Embossing layer

42

Embossing lacquer layer

44

Micro-mirror embossing

46

Color coating

48

Paint coating

50

Grid

52

Grid elements

54

Grid spaces

56

Viewer

58-A, 58-B

Viewing directions

62

Security element

64

Outdoor area

66

Recess

70

Polymer banknote

72

Polymer substrate

80

Paper banknote

82

Paper substrate

84

window

90

Hybrid banknote

92

Hybrid substrate

94

window

96

Paper core

98

Film layer

N

Surface normals

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2015/078572 A1 [0004]
• EP 3254863 A1 [0004]
• EP 1689586 B1 [0015]
• WO 2010/069823 A1 [0015]
• WO 2013/090983 A1 [0015]
• EP 1366380 A2 [0043]

Claims (15)

Optically variable security element for protecting objects of value, the area of which defines a z-axis perpendicular to it, with a multicolored reflective area, wherein - the multicolored reflective surface area contains two optically variable reflection structures which are arranged at different height levels in the z-direction and which produce a different color impression in reflection, - the higher-lying reflection structure is formed by a relief structure provided with a color coating, - the deeper-lying reflection structure is formed by a layer with platelet-shaped, reflective effect pigments which are spatially aligned, - the two reflection structures overlap in an overlap area and the color coating of the higher-lying reflection structure in the overlap area has at least one recess in which the deeper-lying reflection structure appears when viewing the security element. Security element after Claim 1 , characterized in that the flake-form effect pigments represent magnetically alignable magnetic pigments or flake-form effect pigments alignable by other fields. Security element after Claim 1 or 2 , characterized in that the effect pigments are formed by metallized pigments, by pigments with a thin film coating, by reflective metal pigments with a translucent color coating or by pigments with structural colors. Security element according to at least one of the Claims 1 to 3 , characterized in that the effect pigments are present in a printing layer with a transparent or translucent binder and / or the relief structure is embossed in a transparent or translucent embossing lacquer layer. Security element according to at least one of the Claims 1 to 4th , characterized in that the color coating of the higher-lying reflection structure is designed as a regular or irregular grid with grid elements and grid spaces, the dimensions of the grid elements and / or grid spaces at least in one direction below 140 µm, preferably that the dimensions of the grid elements and / or grid spaces in one or both lateral directions are below 140 μm, preferably between 20 μm and 100 μm, in particular between 20 μm and 60 μm. Security element after Claim 5 , characterized in that the grid elements and grid spaces of the grid have the same shape and preferably also the same size, and / or that the area coverage of the grid by the grid elements is between 30% and 70%, preferably between 40% and 60%, in particular around 50 % lies. Security element according to one of the Claims 1 to 6th , characterized in that, in the overlap area, the color coating of the higher-lying reflective structure is applied in partial areas that have lateral dimensions of more than 140 µm, and / or that the colored coating of the higher-lying reflective structure is produced with recesses, the lateral dimensions of more than 140 µm. Security element according to at least one of the Claims 1 to 7th , characterized in that the relief structure of the higher-lying reflection structure is formed by a micromirror arrangement with directed micromirrors, in particular with plane mirrors, concave mirrors and / or Fresnel-like mirrors. Security element according to at least one of the Claims 1 to 8th , characterized in that the color coating is formed by translucent colors, by metallizations, thin-film structures, by translucent colors deposited with a metallization, by luminescent inks with a metallic mirror coating, by structural colors and / or by nanoparticle colors. Security element according to at least one of the Claims 1 to 9 , characterized in that in the overlap area at least a partial area is provided with a negative marking , in which the color coating of the higher-lying reflection structure and the effect pigments of the lower-lying reflection structure are left out. Data carrier with an optically variable security element according to at least one of the Claims 1 to 10 . Disk to Claim 11 , with a carrier with opposing main surfaces, on each of which one of the two optically variable reflection structures is arranged, the carrier being transparent in the overlapping area or containing a transparent see-through window. Disk to Claim 10 , with a carrier with opposite major surfaces, where both optically variable reflection structures are arranged one above the other on a main surface of the carrier. Method for producing an optically variable security element, preferably according to one of the Claims 1 to 10 , in which - a support is provided, the surface extent of which defines a plane and a z-axis perpendicular to it, - the support is provided with a multicolored reflective surface area, which is formed with two optically variable reflection structures that are different in the z-direction Height levels are arranged and which produce a different color impression in reflection, - the higher-lying reflection structure is formed by a relief structure provided with a color coating, - the lower-lying reflection structure is formed by a layer with platelet-shaped, reflective effect pigments, which are spatially aligned, and the two reflection structures are formed to overlap in an overlap area and the color coating of the higher-lying reflection structure is formed in the overlap area with at least one recess in which the deeper one when viewing the security element lying reflection structure appears. Procedure according to Claim 14 , characterized in that for the formation of the deeper-lying reflection structure - a printing ink with a binding agent and effect pigments which can be aligned magnetically or by other fields is applied, - the effect pigments are aligned with an external field, in particular an external magnetic field, while the binding agent is still in a liquid state, to create the desired spatial alignment, and - the binder is solidified in order to permanently fix the alignment of the effect pigments.

Images