Optically variable security element, and value document comprising such a security element

Abstract

The invention relates to optically variable security elements for safeguarding valuable items, comprising a reflective surface region which contains a plurality of reflective pixel elements which, depending on the viewing angle, together display a motif that includes at least one representation of a curve which, when viewed from a first viewing direction, is visible within a display region as a predefined curve in a central position, and, when the security element is tilted about two different predetermined axes, moves within the display region in different directions away from the central position; or which together generate an optically variable motif representation, the visual appearance of which changes when the security element is tilted about two independent axes.

Description

[0001]Optically Variable Security Element and Security Document with Such a Security Element. The invention relates to an optically variable security element for securing valuables, comprising a reflective surface area containing a plurality of reflective pixel elements which together display a motif with at least one curve representation, depending on the viewing angle. This curve is visible from a first viewing direction within a display area in a central position as a predetermined curve and moves away from the central position in different directions when the security element is tilted about two different predetermined axes within the display area. The invention also relates to an optically variable security element for securing valuables, comprising a reflective surface area containing a plurality of reflective pixel elements which together generate an optically variable motif representation.whose appearance changes when the security element is tilted about two independent axes. The invention further relates to a security document with one of the aforementioned security elements. Data carriers, such as securities or identification documents, but also other valuables, such as branded goods, are often provided with security elements for protection, which allow verification of the authenticity of the data carriers and simultaneously serve as protection against unauthorized reproduction. Foil-based security elements have long been used to secure banknotes, securities, and identification documents. Embossed holograms, as used since the late 1980s, are now very widespread and therefore no longer offer a high level of protection against counterfeiting. For this reason, micro-optical systems, for example based on micromirrors, have recently been increasingly used.Used for authentication purposes, security elements with micro-optical systems are generally still easily visible even under unfavorable lighting conditions and allow for the creation of attractive optical effects. For example, micromirrors can be used to create scrolling effects that exhibit high optical variability when the security element is tilted in a specific direction. However, it has been found that when the element is tilted perpendicular to the effect direction, the scrolling effects or other optically variable effects are often only visible in a narrow area, or, in a wider area of ​​visibility generated by a random orientation offset of the micromirrors perpendicular to the effect direction, they exhibit a grainy, gritty appearance. Based on this, the invention aims to...The invention aims to provide a generic security element with high counterfeit protection and an attractive visual appearance. It also aims to provide a security document and a method for manufacturing such a security element. This objective is achieved by the features of the independent claims. Further developments of the invention are the subject of the dependent claims. In a first aspect, the invention comprises an optically variable security element for securing valuables, with a reflective surface area containing a plurality of reflective pixel elements. The reflective pixel elements together display, depending on the viewing angle, a motif with at least one curve representation, which is visible as a target curve in a central position from a first viewing direction within a display area.and which, when the safety element is tilted around two different predetermined axes within the display area, moves in different directions away from the center position. For each pixel element, a parallel direction is defined, parallel to the predefined curve in the center position, and a normal direction is defined, perpendicular to the predefined curve in the center position. Each pixel element further has a first direction in the plane of the reflective surface area, along which the pixel element exhibits a constant inclination to the reflective surface area, except for any isolated discontinuities, whereby the constant inclination in the first direction is chosen depending on the distance of the respective pixel element to the predefined curve. Each pixel element further has a second direction in the plane of the reflective surface area, perpendicular to the first direction, along which the pixel element exhibits an inclination to the reflective surface area.the inclination varies within a given range of inclinations across the entire area or within two or more sub-areas visible to the naked eye, except for any isolated discontinuities. In other words, the inclination of each pixel element in the second direction within the area (or the aforementioned sub-areas) is not constant, but varies within the respective pixel element within the given range of inclinations (as always, except for any isolated discontinuities). The first direction corresponds either to the aforementioned parallel direction and the second direction to the aforementioned normal direction.Or, conversely, the first direction corresponds to the normal direction and the second direction to the parallel direction. These two different assignments lead to different movement behavior of the curve representation when the safety element is tilted, as explained in more detail below. A particular advantage of this design of the pixel elements is that the curve representation appears with a substantially uniform brightness in its different movement positions. Each pixel element can contain one or more reflective facets. If a pixel element contains multiple facets, the height profile of the pixel element typically exhibits a jump at the interface between adjacent facets.which also results in an isolated discontinuity in the tilt of the pixel element along the first and / or second direction. In an advantageous embodiment, all pixel elements contain the same number of reflective facets. The facets of a pixel element advantageously each have the same tilt distribution in the first and second directions. Essentially uniform brightness means that while the brightness of the area or sub-areas can vary in intensity when tilted along the second direction, the brightness in the visible range varies only slowly, and the brightness distribution is smooth, i.e., not grainy or gritty. Furthermore, any intensity variations within the visible range are advantageously small.In particular, less than 10% or even less than 5% of the maximum brightness. In an advantageous embodiment, the inclination of the pixel elements varies continuously along the second direction, except for any isolated discontinuities, so that the pixel elements have a curved profile in the second direction. In particular, with a continuous variation of the inclination, all inclination values ​​within the specified inclination range are actually assumed at least once. For example, the specified inclination range can extend from -10° to +10°, whereby all inclination values ​​between -10° and +10° are assumed due to the continuous curvature. Preferably, the pixel elements have a convex profile, a concave profile, or a convex profile in at least one sub-area and a concave profile in at least another sub-area, except for any isolated discontinuities, in the second direction. In another,In another advantageous embodiment, the inclination of the pixel elements along the second direction is constant section by section, except for any isolated discontinuities, with the inclination assuming at least 3, preferably at least 5, different inclination values ​​within the specified inclination range. In particular, with a section-by-section constant variation of the inclination, the maximum and minimum values ​​of the inclination range, as well as at least one, preferably at least 3, different values ​​from within the inclination range, are assumed. For example, the specified inclination range can extend from -10° to +10°, with the section-by-section constant inclination values ​​being -10°, -5°, 0°, +5°, and +10°. A section-by-section constant inclination results in a particularly high, smooth brightness when tilted, although the intensity may vary slightly. To ensure particularly small intensity fluctuations,The angular spacing of adjacent inclination values ​​is advantageously chosen to be smaller than the scattering angle range of the planar facet segments. The specified inclination range expediently has an angular extent between 10° and 90°, preferably between 15° and 40°, and particularly preferably between 15° and 25°. The inclination range can be asymmetrical to the normal; for example, an inclination can exist only in the east direction but not in the west direction. Advantageously, however, the specified inclination range is essentially symmetrical to the normal of the reflective surface area. Advantageously, the pixel elements have an axisymmetric profile with respect to an axis in the normal direction, the axis preferably passing through the center of the respective pixel element. In an advantageous embodiment, it is provided that the constant inclination in the first direction is monotonicallyIn particular, the curve increases or decreases strictly monotonically with the distance of the respective pixel element from the target curve, preferably that the constant inclination in the first direction increases or decreases linearly with the distance of the respective pixel element from the target curve. These measures advantageously make the curve representation appear to lie above and / or below the safety element (often referred to as "floating" in this description). In an advantageous variant, the curve representation moves parallelally when the safety element is tilted about the different predetermined axes, so that the movement against the background of the safety element makes the curve representation appear three-dimensional and appear to lie above and / or below the safety element. A three-dimensional appearance with a curve representation appearing to float above or below the safety element is created in particular by...that for each point of the curve representation, a pair of pixel elements (one pixel element per eye) is present in the reflective surface area, so that the two eyes of a viewer are presented with slightly different perspective images, which are combined in the viewer's brain to form a three-dimensional impression. Advantageously, the curve representation shows at least one closed curve as the reference curve, in particular two concentric ellipses or concentric rings. In an advantageous further development, the motif contains at least a first and a second curve representation, which are visible from a first and second viewing direction, respectively, within a first and second display area, respectively, in a central position as the first and second reference curve, respectively, wherein the two curve representations shift into different positions when the safety element is tilted.preferably move in opposite directions. In a second aspect, the invention includes an optically variable security element for securing valuables, with a reflective surface area containing a plurality of reflective pixel elements. The reflective pixel elements together generate an optically variable motif representation, the appearance of which changes when the security element is tilted about two independent axes. Each pixel element has a first direction in the plane of the reflective surface area, along which the pixel element exhibits a constant, pixel-specific inclination to the plane of the reflective surface area, except for any isolated discontinuities. Each pixel element also has a second direction in the plane of the reflective surface area, perpendicular to the first direction, along which the pixel element exhibits an inclination to the plane of the reflective surface area.which varies across the entire surface area or in two or more sub-areas visible to the naked eye, except for any isolated discontinuities, within a pixel-specific tilt range. In other words, the tilt of each pixel element in the second direction within the surface area (or the aforementioned sub-areas) is not constant, but varies within the respective pixel element within the pixel-specific tilt range (as always,(except for any isolated discontinuities). The motif representation, or at least parts of it, generated by the multitude of reflective pixel elements, moves in different directions when the security element is tilted around the two independent axes. More precisely, when the security element is tilted around the first of the two independent axes, the aforementioned motif representation, or at least parts of it, moves in a first direction, and when the security element is tilted around the second of the two independent axes, it moves in a second direction, different from the first. It is particularly advantageous that – the optically variable motif representation is formed by a plurality of line elements or approximated by a plurality of line elements, – the constant inclination in the first direction and the inclination range in the second direction are chosen for each pixel element.to generate one of the aforementioned line elements of the motif representation, and – the line elements generated by the multitude of reflective pixel elements create an appearance in which the motif representation, or at least parts of the motif representation, move in different directions when the security element is tilted about the two independent axes. In an advantageous embodiment, it is provided that the motif representation, or at least parts of the motif representation, move parallactically when the security element is tilted about the two independent axes, so that the motif or the motif parts appear three-dimensional and seem to lie above and / or below the security element. A three-dimensional appearance with a curve representation appearing to float above or below the security element is created in particular by…that for each point of the motif or motif parts, a pair of pixel elements (one pixel element per eye) is present in the reflective surface area, so that the two eyes of a viewer are presented with slightly different perspective images, which are combined in the viewer's brain to form a three-dimensional impression. The constant inclination in the first direction is advantageously selected depending on the distance of the respective pixel element to the generated line element. It is further advantageous that the constant inclination in the first direction increases or decreases monotonically, in particular strictly monotonically, with the distance of the respective pixel element to the generated line element, preferably that the constant inclination in the first direction increases or decreases linearly with the distance of the respective pixel element to the generated line element. According to a preferred embodiment, the motif representation includes an elliptical ring,In particular, an annulus that appears to float above or below the safety element, wherein the first direction for the pixel elements contributing to the generation of the annulus is the radial direction towards the center of the elliptical ring or annulus. Preferably, the elliptical ring or annulus is approximated by a group of line elements, and the first direction for the pixel elements that generate the line elements of said group is the radial direction towards the center of the elliptical ring or annulus. The motif representation advantageously includes at least two elliptical rings, in particular two annulus rings, that appear to float at different heights or depths, preferably one ring appearing to float above and one ring below the safety element.and wherein the rings are concentric to each other from a specific viewing direction of the safety element. In a preferred embodiment, adjacent pixel elements each exhibit a similar first direction in certain areas, such that a substantially continuous progression of the first direction results in each of the aforementioned areas. In a further development of the invention, both aspects may be further provided that the reflective surface area contains at least two subgroups, each with a plurality of pixel elements, as well as at least one coexistence area.in which pixel elements from at least two of the aforementioned subgroups are located. The pixel elements are each assigned optical structures, and the pixel elements of at least one subgroup participating in the coexistence area are designed in the manner described for the first or second aspect. Each of the subgroups participating in the coexistence area generates a partial motif visible from a specific visibility area, whereby the visibility areas of the participating subgroups are not congruent, so that for each participating subgroup there is a partial visibility area in which the partial motifs generated by the other participating subgroups are not visible. Preferably, it is provided thatthat the dimensions of the pixel elements are below the resolution limit of the human eye, or that at least the surface areas of the subgroups cannot be distinguished with the naked eye. The pixel elements of one of the participating subgroups can also be provided with planar facets of the type described in publication WO 2016 / 180522 A1, in which the planar facets have a first inclination component that is selected depending on the distance of the respective facet to the reference curve or the motif representation, and a second of the two inclination components in a predetermined fanning area is selected independently of the distance of the respective facet to the reference curve or the motif representation, and is preferably irregular in the fanning area.in particular varies according to a random number distribution or a pseudorandom number distribution. In an advantageous embodiment, there is no overlap between the visibility areas of the subgroups involved. In a further preferred embodiment, the pixel elements are divided into exactly two subgroups, so that an optical flip (switch) between two different sub-motifs or different optical effects occurs. Also in both aspects, an advantageous further development of the invention may provide that the reflective surface area is divided into at least two sub-areas, which are in particular designed in the form of a pattern, motif, or encoding. At least one first sub-area is covered with pixel elements that are designed in the manner described for the first or second aspect of the invention and that produce a movement effect, in particular a running effect.in an effect direction which is visible in a visibility range perpendicular to the effect direction. At least one further, second sub-area is provided with pixel elements that are not designed according to the type described for the first or second aspect, and which macroscopically produce essentially the same movement effect in the effect direction and essentially the same visibility range perpendicular to the effect direction as the pixel elements of the first sub-area. 5 In an advantageous modification of the invention, it can be provided that the at least one further, second sub-area is provided with pixel elements that are not designed according to the type described for the first or second aspect, and which macroscopically produce essentially the same movement effect in the effect direction,but perpendicular to the direction of the effect, they generate a different visibility area than the pixel elements of the first sub-area. The pixel elements of the second sub-area can, in particular, be provided with planar facets of the type described in publication WO 2016 / 180522 A1, in which the planar facets have a first inclination component that is selected depending on the distance of the respective facet to the reference curve or the motif representation, and a second of the two inclination components is selected in a predetermined fanning range independently of the distance of the respective facet to the reference curve 20 or the motif representation, and preferably varies irregularly in the fanning range, in particular according to a random number distribution or a pseudorandom number distribution. The two modifications described last allow the security 25 element to be provided with an additional hidden authentication feature.Since the appearance of the first and second sub-areas appears very similar upon superficial inspection or from a greater viewing distance, differences in the appearance of the two sub-areas only become apparent upon closer examination. For example, the generated motifs may appear smooth and uniform in the first sub-area upon close inspection, while appearing grainy and gritty in the second sub-area, or the visibility areas of the motifs may differ when the safety element is tilted perpendicular to the direction of the effect. In all the aforementioned variants, the pixel elements advantageously have dimensions between 3 µm and 100 µm, preferably between 5 µm and 20 µm. Alternatively or additionally, the pixel elements have a maximum pitch between 0.5 µm and 10 µm, preferably between 1 µm and 5 µm. Advantageously, the pixel elements all have the same shape.For example, all pixel elements are square or rectangular. Another further development provides that all pixel elements have the same inclination profile in the second direction, for example, the same concave or convex curvature. Alternatively, it can be provided that the reflective surface area contains several groups of pixel elements, in which the pixel elements have a uniform, group-specific,but exhibit different inclination profiles in different groups. For example, the pixel elements in a first group are all concave in the same way, and in a second group, they are all convex in the same way. The pixel elements can also be concave (or convex) in a wide inclination range in a first group and concave (or convex) in a narrow inclination range in a second group. In all the above variants, the reflective pixel elements can each be equipped with a property from Group A and / or a property from Group B below. Group A, structure combinations: a) Without nanostructures, i.e., only curved / planar mirror surfaces b) All pixel elements are covered with nanostructures, including the following possibilities: i) Structures with the same structural parameters everywhere, especially height, diameter, period,Arrangement in one or two dimensions, or even specifically aperiodic randomly distributed nanostructures; ii) Nanostructures with different structural parameters are used across the surface of the security element. Among others, the following possibilities: α) Area-specific constant structural parameters, for example, multicolor images or differently colored flip motifs; β) Continuous variation of one or more structural parameters to, for example, create color gradients; c) There are areas without nanostructures and areas with nanostructures: i) the areas with nanostructures all have the same structural parameters; ii) the areas with nanostructures can all have different structural parameters (more color, color gradients). The curved or flat mirror surfaces of the reflective pixel elements significantly determinein which direction incident light is reflected. Any additional nanostructures do not change the direction of reflection of the incident light, but rather create a color that differs from the color of the coated surface without nanostructures. The nanostructures thus modify the natural color effect (with a constant color or a color shift) of the coating, making it possible to create colors or color combinations that would not be possible without nanostructures. It may be provided thatthat the curved mirror surfaces of the pixel elements are completely covered with a specific nanostructure (and thus color). Advantageously, the surface of a pixel element can also be divided into sub-areas with different nanostructures. In particular, the nanostructure can be chosen depending on the local orientation of the curved mirrors. For example, the surface areas of a curved mirror oriented in a first direction (e.g., "north") can be covered with red-producing nanostructures, and all surface areas oriented in a second direction (e.g., "south") can be covered with green-producing nanostructures. As a result, the effect presented by this curved mirror can be observed as red from the first (north) direction and as green from the second (south) direction. It goes without saying thatthat other color combinations can also be selected. The dependence of the selected nanostructure on the local orientation of the pixel elements can be the same for all pixel elements (resulting in a full-surface, angle-dependent color change) or can be chosen differently for individual pixel elements or groups of pixel elements (resulting, for example, in a multicolored image from a specific angle that exhibits locally different color changes when tilted). In an advantageous embodiment, continuously curved mirror surfaces can be provided with a continuously changing nanostructure such that, when tilting the safety element, a viewer perceives a dynamic effect caused by the mirror curvature coupled with a continuous color transition. The assignment can be carried out in such a way thatThe local slope (normal vector) is determined at a specific location on a curved mirror, and the corresponding specific nanostructure is then assigned to this normal vector. Locations with the same local orientation then exhibit, for example, the same nanostructure. The nanostructures can be designed as protrusions and / or depressions relative to the surrounding surface. Advantageously, these nanostructures have a lateral size between 50 nm and 450 nm, particularly between 100 nm and 300 nm, and / or a depth between 20 nm and 450 nm, particularly between 100 nm and 300 nm. In the case of periodic arrangements of the nanostructures (in one or two dimensions), the period length in at least one direction can be chosen between 50 nm and 600 nm, particularly between 50 nm and 450 nm. In the case of two-dimensional periodic arrangements, the nanostructures form, in particular, lattices with rectangular, square, or diamond-shaped patterns.hexagonal or parallelogram-shaped lattice symmetry. In cross-section, the nanostructures can advantageously have a nearly binary or rectangular profile with steep, ideally perpendicular, flanks. They can also have a rounded, for example, sinusoidal or sinusoidal profile, offering other advantages, such as improved moldability. Group B, coatings: a) Reflective metal layers, for example, of aluminum, silicon, silver, gold, copper, chromium, titanium, iron, nickel, or an alloy of two or more of these metals; b) Dielectrics, in particular with a refractive index that differs from that of an embossing / sealing lacquer used in the security element, for example, ZnS, MgF2, HfO2, SiO2. In addition, low-refractive-index dielectric materials with a refractive index of 1.65 or less are suitable, in particular selected from the group consisting of silicon dioxide (SiOx), silicon dioxide (SiO2),Aluminum oxide (Al₂O₃), metal fluorides, for example magnesium fluoride (MgF₂), aluminum fluoride (AlF₃), cerium fluoride (CeF₃), sodium aluminum fluorides (e.g., Na₃AlF₆ or Na₅Al₃F₁₄), neodymium fluoride (NdF₃), lanthanum fluoride (LaF₃), samarium fluoride (SmF₃), barium fluoride (BaF₂), calcium fluoride (CaF₂), lithium fluoride (LiF), low-refractive-index organic monomers and / or low-refractive-index organic polymers, or at least a high-refractive-index dielectric material with a refractive index greater than 1.65, in particular selected from the group consisting of zinc sulfide (ZnS), zinc oxide (ZnO), titanium dioxide (TiO₂), carbon (C), indium oxide (In₂O₃), indium tin oxide (ITO), tantalum pentoxide (Ta₂O₅), cerium oxide (CeO₂), and yttrium oxide. (Y2O3), europium oxide (Eu2O3), iron oxides such as (II) iron(III) oxide (Fe3O4) and iron oxide (Fe2O3), hafnium nitride (HfN), hafnium carbide (HfC), hafnium oxide (HfO2), lanthanum oxide (La2O3), magnesium oxide (MgO), neodymium oxide (Nd2O3), praseodymium oxide (Pr6O11), samarium oxide (Sm2O3),Antimony trioxide (Sb₂O₃), silicon carbide (SiC), silicon nitride (Si₃N₄), silicon monoxide (SiO₂), selenium trioxide (Se₂O₃), tin oxide (SnO₂), tungsten trioxide (WO₃), high-refractive-index organic monomers and / or high-refractive-index organic polymers. c) Layer systems: i) Color-shifting coating consisting of: - a semi-transparent reflector (especially thin Cr / Ti / Al; thicknesses of a few nm or around 10 nm) or a metallic material selected from the group consisting of nickel, titanium, vanadium, chromium, cobalt, palladium, iron, tungsten, molybdenum, niobium, aluminum, silver, copper and / or alloys of these materials; - a dielectric, for example SiO₂ / ZnS; with thicknesses of a few to several hundred nm; – Reflector layer, for example made of Al / Ag / Cu / Au, with thicknesses ranging from a few tens of nm to thicker, opaque reflector layers, or made of a metallic material selected from the group consisting of aluminum, silver, copper, gold, platinum, niobium, tin, or nickel, titanium, vanadium, chromium,Cobalt and palladium or alloys of these materials; ii) Color-changing coating made of: – a semi-transparent reflector, for example, thin Al / Cr / Ti; with thicknesses of approximately 10 nm; – a dielectric, for example, SiO2 / ZnS; with thicknesses of a few to several hundred nm; – a semi-transparent reflector, for example, thin Al / Cr / Ti; with thicknesses of approximately 10 nm. iii) Other multilayer systems consisting of different dielectrics / metals (materials as above), wherein a refractive index transition occurs at the interface between the layers, leading to reflection. The layer thicknesses can be chosen to produce a controlled constructive interference, or to avoid controlled interference.to obtain increased broadband reflection. Alternating dielectric layers with different refractive indices (interference at a multilayer system) are advantageous. Layer systems consisting of a metallic reflector and a semiconductor, for example Si, are also advantageous. High-refractive-index or low-refractive-index materials (relative to the adjacent material) over a metallic reflector, for example ZnS-aluminum, are also advantageous. d) Liquid crystals, especially cholesteric liquid crystals, can also be used as color-shifting layers. For all these coatings of group B, additional adhesion promoter layers, for example very thin layers of chromium, titanium, or polymer primers, can be used.to create better adhesion. These can be used between the embossing varnish / sealing varnish and the coating, but also between individual layers of the coating. In a preferred embodiment, the reflective surface area in all variants can have at least one metallized sub-area and one demetalized sub-area. In a preferred embodiment, at least one demetalized sub-area is created by a washing process in which a wash ink, i.e., a printing ink with low adhesion, is applied to the desired sub-area before the coating steps.and the wash color is removed along with the coating layers after coating. In another preferred variant, at least one demetallized sub-area has etch support structures to increase the etch rate of a coating. After coating both the subsequently metallized and the subsequently demetallized sub-areas, the coating is completely removed (or in desired layers) from the latter sub-areas in an etching process, while sufficient material remains on the former sub-areas. By equipping sub-areas with such etch support structures, a perfect match of the reflection properties (reflective / non-reflective, e.g., transparent) with other effects, such as motif boundaries, can be achieved, since both the effect-generating structures and the etch support structures are created in the same operation.in particular, they can be embossed. In this context, demetallization refers to the removal of one or more, in particular reflective and typically metallic, coating layers. The invention also includes a security document, in particular a banknote, with a security element of the type described according to the first and / or second aspect of the invention. Further features of the invention will become apparent from the claims, the figures, and the figure description. Exemplary embodiments of the invention are explained in more detail below with reference to schematic drawings. In the figures, identical or functionally equivalent elements are provided with the same reference numerals. Figure 1 shows a schematic representation of a banknote with an optically variable security element according to the invention, and Figure 2 shows a schematic view of a security element in various tilted positions.wherein the security element is designed with a reflective surface area with an outer contour in the form of the value number "10", Fig. 3 shows a detail section of the reflective surface area of ​​the security element of Fig. 2 with 3x3 pixel elements in top view, Fig. 4 shows the height profile within a pixel element of Fig. 3, where (a) shows a grayscale representation and (b) and (c) show the height profile of the mirror surface within the pixel element in a north-south direction and east-west direction, respectively, Fig. 5 shows a three-dimensional representation of the height profile of a pixel element, Fig. 6 shows a detail section of the reflective surface area of ​​a security element according to another embodiment, Fig. 7 shows (a) a schematic top view of a planar motif area with a curved line and (b) a detail view, Fig. 8 shows a planar motif area with a circular ring floating below the motif area in various Views,Fig. 9 shows a motif representation in the form of the letter "P" to illustrate the procedure for designing the pixel elements in the second aspect of the invention, and Fig. 10 illustrates an alternative procedure for designing the pixel elements. 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 100 according to the invention in the form of an affixed transfer element. It is understood, however, that the invention is not limited to transfer elements and banknotes, but can be used for all types of security elements, for example, for labels on goods and packaging or for securing documents, identity cards, passports, credit cards, etc.Health cards and the like. In the case of banknotes and similar documents, in addition to transfer elements (such as strips or patches with or without their own backing film), security threads or security strips partially or completely embedded in the document substrate are also considered. The security element 100 has a reflective surface area 102 that shows a motif 104 with two circular rings 106, 108, whereby the first circular ring 106 appears to float below the security element and the second circular ring 108 above the security element. From a certain viewing direction, the circular rings 106, 108 appear to be arranged concentrically; however, when the security element is tilted in different directions 116, 118, the circular rings 106, 108 appear to move away from their concentric central position. More precisely, the circular rings 106,108 When the safety element is tilted, it exhibits a parallax motion behavior that corresponds to the motion of two real, superimposed circular rings when the viewing direction changes, thus creating a convincingly three-dimensional appearance for the viewer. As a further special feature, the two circular rings 106, 108 appeared to the viewer with essentially uniform brightness in their different positions. An arrangement of reflective pixel elements is used to generate the described motion effect and the uniform brightness of the circular rings.which each have a substantially constant inclination in one direction and are curved in a suitable manner in a direction perpendicular to it or are provided with several sections of constant inclination. Therefore, as a preliminary step, some basic embodiments with reflective pixel elements with direction-dependent constant or curved inclination are described in more detail, and the emergence of the special effects produced by the mirror curvature is explained. Such reflective pixel elements can also be used in the designs according to the invention. Figure 2 shows a safety element 12 with a reflective surface area 14, which is formed with an outer contour in the form of the value number "10". As shown in the detailed view of Fig. 3, the reflective surface area 14 is divided into a plurality of small, reflective pixel elements 20,which together generate the optically variable representation of the value "10" of the security element 12. The pixel elements 20, for example, have dimensions of 20 µm x 20 µm and each contains three ray-optically acting reflective facets 22, which direct incident light like small mirrors into a reflection direction determined by the condition "angle of incidence equals angle of reflection". The pixel elements 20 are therefore also referred to as micromirrors in this description. The inclination of the facets or the pixel elements is set in the manner described in more detail below such that the appearance of the representation of the number "10" changes when the security element 12 is tilted, thus generating an optically variable appearance. Depending on the tilting direction 16, the security element 12 displays18 different behavior. With reference to Figures 1 and 2, a tilting in a first direction 16 is hereinafter referred to as a north-south tilt, and a tilting in the second tilting direction 18 perpendicular to it is referred to as an east-west tilt. The use of cardinal directions serves only for the simple naming and illustration of the different tilting processes; it is understood that the first and second directions do not have to coincide with the actual cardinal directions. Without tilting, i.e., when viewed essentially vertically, the surface area 14 of the safety element 12 appears as a metallic, shiny number "10" with a bright horizontal bar 15 approximately in the middle of the two digits (view 20 in Fig. 2). If the safety element 12 is tilted by a user in the north-south direction 16,The bright bar 15 within the number "10" appears to run continuously towards the top or bottom edge of the digits, creating a so-called rolling bar effect (view 20-N or 20-S in Fig. 2). Conventional designs, however, often have the disadvantage that when the security element 12 is tilted in an east-west direction 18, i.e., perpendicular to the main effect direction 16, the rolling bar effect is either only visible within a very narrow angular range, or that the appearance is not smooth but grainy and gritty over a wider viewing area. In contrast, the optically variable rolling bar effect of the security element 12 in an east-west direction is visible from a wide angular range and also appears with a smooth, uniform brightness. More precisely, when viewed perpendicularly, the security element 12 shows the value "10" with a bright, central,horizontal beam 15. When the safety element 12 is tilted in an east-west direction 18, the brightness of the surface area 14 and the beam 15 does not change practically in a visibility range that extends up to a tilt of about 15° to the west (view 20-W) and up to a tilt of about 15° to the east (view 20-O). If the security element 12 is first tilted northwards from the vertical viewing direction, so that the bright bar 15 is located at the upper edge of the value number "10" (view 20-N), then the security element 12, when subsequently tilted in an east-west direction (views 20-NE and 20-NW), also shows a smooth, uniform brightness of the area 14 with the bright bar 15 at the top. If the security element 12 is first tilted southwards from the vertical viewing direction, so that the bright bar 15 is located at the lower edge of the value number "10" (view 20-S),Thus, when safety element 12 is subsequently tilted in an east-west direction (views 20-SE and 20-SW), it again shows a smooth surface.Uniform brightness of the surface area 14 with the bright bar 15 at the top. The uniform visibility and brightness of the rolling bar effect across a wide range of east-west tilt angles increases the recognizability range of the motif 14 compared to conventional designs and significantly improves the visual appearance of the security element 12. This increases the security effect and the recognition value of the security element 12, and thus also its counterfeit resistance. To illustrate how the described appearance of the security element 12 is achieved, Fig. 3 shows a detail of the surface area 14 with 3x3 pixel elements 20 in a top view. In the exemplary embodiment, the pixel elements 20 have a base area of ​​20 µm x 20 µm and a maximum pitch of 3.5 µm. The height profile within a pixel element 20 is illustrated in Fig. 4, where Fig. 4(a) shows a grayscale representation.where the minimum pitch of 0 µm is represented by black and the maximum pitch of 3.5 µm by white. Figures 4(b) and (c) show the height profile of the mirror surfaces along a cross-sectional line within the pixel element 20. Figure 4(b) shows the height profile in the north-south direction 16 along line B1-B1 (curve 30) or line B2-B2 (curve 32) of Figure 4(a), and Figure 4(c) shows the height profile in the east-west direction 18 along line C1-C1 (curve 34) or line C2-C2 (curve 36) of Figure 4(a). The pixel elements 20 of the illustrated embodiment each consist of three facets 22 with the same slope profile in the north-south and east-west directions. At the interfaces where adjacent facets 22 meet, discontinuities occur in the height profile (Fig. 4(b), 4(c)) and thus, in the illustrated embodiment, also up to two isolated discontinuities in the inclination of the pixel elements. As can be seen from Figures 3 and 4,The course of the mirror inclination in the pixel elements in the north-south direction 16 differs significantly from the course of the mirror inclination in the east-west direction 18. In the north-south direction 16, the pixel elements exhibit a constant inclination to the reflective surface area 14, except for two isolated discontinuities, as can be seen from the piecewise linear height profile curves 30, 32 of Fig. 4(b). The inclination, which is constant within each pixel element, changes slowly from south to north across the extent of the surface area 14 from pixel element to pixel element.For example, from -15° at the southern (lower in the figures) edge of area 14 to +15° at the northern (upper) edge of area 14. As a result, for every viewing angle, only the pixel elements 20 lying in a narrow horizontal strip exactly fulfill the reflection condition "angle of incidence equals angle of reflection". Since each pixel element reflects the incident light into a certain scattering angle range of a few degrees, the result is a wide, horizontal bright bar. Due to the continuous increase in the tilt angle from south to north, when the safety element 12 is tilted in the north-south direction, the narrow strip of specular reflection shifts accordingly in the north-south direction.so that the bright horizontal bar appears to run from bottom to top or from top to bottom within the area 14 when tilted in this direction. In contrast, the pixel elements 20 do not have a constant or randomly chosen inclination in the east-west direction 18. As shown in Fig. 4(c), the height profile curves 34, 36 are concave except for any isolated discontinuities. As a result, the inclination of each individual pixel element 20 in the east-west direction varies continuously within a predefined inclination range, for example, from -15° to +15°. This means that each of the pixel elements 20 in the east-west direction is visible from any viewing direction within a wide angular range around the reflecting direction and contributes to the appearance of the area from that viewing direction. The area 14 therefore appears smooth when tilted east-west,uniform brightness. Figure 5 shows, for further illustration, a three-dimensional representation of the height profile 40 of a pixel element 20, where the height component h is greatly exaggerated for clarity. As can be seen in Fig. 5, the height profile 42 of the pixel element is linear in the north-south direction, meaning the inclination of the pixel element 20 is constant in the north-south direction. In the east-west direction, the height profile 44 exhibits a concave curvature; there, the inclination varies continuously within a predetermined, larger symmetrical inclination range. Another embodiment of the invention is illustrated in Fig. 6, which shows a section of the reflective surface area 14 of another safety element 12 according to the invention. The height profile within each of the depicted pixel elements 20 is indicated, as in Fig. 4(a), by a grayscale representation, where the minimum pitch height of 0 µm is represented by black and the maximum pitch height of 3,5 µm is represented by white. The pixel elements 20 of the embodiment shown in Fig. 6 also exhibit a constant inclination in the north-south direction 16, except for isolated discontinuities, while the inclination in the east-west direction 18 varies within a predetermined range. Unlike the embodiment shown in Figures 3 and 4, however, the inclination of the pixel elements in the east-west direction does not vary continuously, but rather abruptly with 5 discrete steps, for example, with the inclination values ​​-10°, -5°, 0°, +5°, and +10°. With such a sectionally constant inclination, the safety element exhibits a particularly high brightness when tilted from east to west, with a smooth brightness gradient that varies slightly in intensity. Figure 6 also illustrates that the facets 22 belonging to pixel elements 20 adjacent in the east-west direction can be offset from each other in the north-south direction. However, the facets can also be, as shown in Fig. 3,in the north-south direction, they are arranged at the same height. Returning to the design of Fig. 1, curved mirrors or mirrors varying in inclination can, according to the invention, also be advantageously used for curve representations, such as the representation of the circles 106, 108 of Fig. 1. To illustrate the principle in the design of the pixel elements, Fig. 7 shows a planar view of a planar motif area 120 of a safety element with a display area 122.In its central position, a curved curve 124 is visible as a reference curve. For a viewer, the curve 124 appears to float a few millimeters above or below the plane of the planar motif area 120 and, when tilted around the x-axis or y-axis, moves in different directions within the display area 122 according to its apparent height or depth of suspension. The curved curve 124 can be controlled at any point by a local direction vector K|| parallel to the curve 124 and a local direction vector K, ⊥perpendicular to the curve 124, as shown in detail section 126 of Fig. 7(b). To generate the curve representation, the display area 122 contains a plurality of reflective pixel elements 128, for each of which a parallel direction R|| parallel to the target curve in the central position (parallel to K||) and a normal direction R⊥ perpendicular to the target curve in the central position (parallel to K⊥) can be defined. The pixel elements 128 each exhibit a constant inclination to the reflective surface area 120 along the normal direction R⊥, except for any isolated discontinuities, whereby the magnitude of the constant inclination is chosen depending on the distance of the respective pixel element 128 to the target curve 124. In other words, while the inclination in the normal direction is constant within a single pixel element 128, the magnitude of the inclination generally changes from pixel element to pixel element.In particular, the magnitude of the constant inclination can increase or decrease monotonically and preferably linearly with the distance of a pixel element 128 from the curve 124. If the pixel elements 128 are inclined increasingly away from the curve with increasing distance, the curve appears to float below the plane of the two-dimensional subject area 120. Conversely, if the pixel elements 128 are inclined increasingly towards the curve with increasing distance, the curve appears to float above the plane of the two-dimensional subject area 120. It is understood that a curve does not have to have a constant floating height, but that the floating height can change along the curve and can even transition from a floating height above the two-dimensional subject area to a floating height below the two-dimensional subject area, or vice versa.Along the parallel direction R|| perpendicular to the normal direction, the pixel elements 128 exhibit a continuously varying inclination within a predefined range, except for any isolated discontinuities, such that the pixel elements 128 each have a curved profile in the parallel direction R||. The size of the inclination range is predefined and chosen independently of the distance of a pixel element 128 from the predefined curve. The inclination range can, for example, be between 15° and 25°, and in practice, can be approximately 20°. Such a distance-independent variation of the inclination in the parallel direction results in a dispersion of the incident light parallel to the local direction of the predefined curve 124, the magnitude of which is advantageously comparable to the parallax effect caused by changing the constant inclination.The continuous variation of the pixel elements' inclination in the parallel direction ensures that the three-dimensional depth impression, in particular the apparent floating of the reference curve 124 at a specific height or depth, is maintained even if the viewer tilts the security element within a certain angular range or rotates it in the plane of the security element. The curve 124 can, in principle, have any shape, but preferably represents letters, numbers, symbols, or simple geometric shapes such as circles, ovals, triangles, rectangles, or squares. Circular rings, especially two circular rings floating at different heights, as shown in Fig. 1, have proven to be a particularly easy-to-understand design. The principle described above allows for both parallactic and orthoparallactic movement of such circular rings when the security element is tilted.Figure 8 illustrates the movement effects, first for a motif with a single circular ring 106. The figure shows, in the middle view 130-M, a flat motif area 120 with a dashed representation area 122, in which the circular ring 106 is visible in the center when viewed vertically and appears to float below the flat motif area 120. When viewed from above (view 130-O), the circular ring 106 moves to the upper edge of the representation area 122; when viewed from below (view 130-U), it moves to the lower edge. Accordingly, when viewed from the right (view 130-R), the circular ring 106 moves to the right edge, and when viewed from the left (view 130-L), it moves to the left edge of the display area 122. This movement behavior corresponds to the movement behavior of an object located in depth and therefore reinforces the three-dimensional impression of the ring floating in depth. As shown in Fig.As described in section 7, such an appearance and movement behavior can be achieved by tilting the pixel elements in the display area 122 away from the circular ring 106 at a constant angle in the direction perpendicular to the direction vector K|| of the circular ring 106, with the angles of inclination increasing linearly with the distance of the pixel elements from the circular ring 106. In the direction parallel to the direction vector K||, the pixel elements, on the other hand, have a curved profile with an inclination that varies independently of the distance to the circular ring 106. The resulting fanning-out area in the parallel direction allows the viewer to perceive the circular ring with uniform brightness within a certain range, even when tilting or rotating the safety element.For a second circular ring 108, the appearance and movement behavior of an object hovering above the safety element can be generated by moving the pixel elements in the display area 122 in a direction perpendicular to the direction vector K. ||The pixel elements are inclined at a constant angle to the circular ring 108, with the angles of inclination increasing linearly with the distance of the pixel elements from the circular ring 108. The interaction of two such circular rings 106, 108 can thus generate the appearance and movement behavior described in Fig. 1. Instead of an intuitively correct parallactic movement behavior, curved representations with counterintuitive, orthoparallactic movement behavior can also be generated with the pixel elements, where the movement behavior does not correspond to that of a real object. For this, the assignments of the first direction (constant inclination) and the second direction (variation in the inclination range) to the parallel and normal directions of the pixel elements simply need to be reversed.The pixel elements then exhibit a constant inclination to the reflective surface area along the parallel direction R||, except for any isolated discontinuities, while in the normal direction R⊥ they exhibit a continuously varying inclination within a predefined range, thus exhibiting a curved profile. This corresponds precisely to a rotation of the pixel elements by +90° or -90°. Combinations of height / depth effects and orthoparallel motion effects can also be generated by rotating the pixel elements by any angle other than an integer multiple of 90°, starting from a height or depth effect. Curved mirrors, or mirrors with varying inclinations in general, can be used not only for optically variable curve representations but also for generating more general, optically variable motifs composed of line elements.The inventive method is based on an implementation for planar pixel elements, in which the following procedure is performed for a motif consisting of a multitude of points: 1) In a first step, each sub-motif, and thus also each point of this sub-motif, is assigned a movement range within which the sub-motif is to move when viewed. 2) Then, for each pixel element, it is checked which points (which may also originate from different sub-motifs) can reach this pixel element within its movement range. 3) From the list of possible points, a point is then selected, for example, randomly, and the orientation and slope of the mirrors in this pixel are calculated based on the relative position of the selected point to the pixel element. 4) Pixel elements that cannot be reached by any point are assigned a predefined background setting for orientation and slope.Since, in this implementation, a pixel element can usually be reached from several adjacent points of a motif, one of the possible points must be selected in these cases, which sometimes leads to a grainy, gritty appearance. Here, the current inventors have recognized that the adjacent points relevant for generating a sub-motif generally yield very similar values ​​when calculating the orientation and slope of the plane mirrors. Instead of randomly selecting one of these values ​​for the slope in each case, a multitude of similar slopes can be realized simultaneously in a curved pixel element by using curved mirrors. Adjacent pixel elements thus become more similar to each other, the overall pixel distribution more homogeneous and uniform, resulting in a more consistent brightness of the appearance produced by the pixel elements. The specific procedure will now be illustrated with reference to Fig.Figure 9 illustrates this with a simple example: a motif representation 140 in the form of the letter "P", which is formed by a plurality of line elements 142. Considering first the straight vertical stem (line 144) of the letter "P" and a pixel element 150 located horizontally next to line 144, there is a point 146 on line 144 that is located horizontally exactly next to this pixel element 150. If the pixel element 150 is to contribute to the representation of this point 146, the pixel element must be formed with a certain inclination in the horizontal east-west direction (OW), but without inclination in the vertical north-south direction (NS). The points 148 adjacent to point 146 lie on the same vertical line 144, thus producing the same east-west inclination at the location of pixel element 150 due to the identical horizontal distance as point 146.In the north-south direction, however, points 148 generate slightly different inclinations because the vertical distance of the points to pixel element 150 changes. The inclinations generated by points 146 and 148 of line 144 within a defined range of movement 152 can be realized in a single pixel element 150. For this purpose, pixel element 150 is given a constant inclination in a first direction, namely the east-west direction OW, except for any isolated discontinuities. The magnitude of this inclination is determined by the horizontal distance of pixel element 150 to line 144. In the second, perpendicular direction, namely the north-south direction NS, the pixel element 150 is curved or formed with a plurality of piecewise constant sections, so that it has a multitude of inclinations in this direction, which are required for the representation of the points 146, 148 lying within the range of movement 152.The inclinations occurring within the range of motion 152 in the north-south direction therefore precisely determine the inclination range of the pixel element 150 in the second direction. The described procedure can readily be extended to lines or line elements 142 of any orientation. The first direction (east-west direction for pixel element 150) corresponds, for a general line element 142, to the normal direction perpendicular to the line element 142, and the second direction (north-south direction for pixel element 150) to the parallel direction parallel to the line element 142. In this way, almost any motif representation can be given an optically variable effect using pixel elements that are constantly inclined in one direction and curved in another.The motif representation simply needs to be decomposed into line elements or approximated by a plurality of line elements, and the design of the pixel elements is calculated based on the line elements they are intended to represent. If a pixel element can be reached by points of several line elements of the motif representation, one of these lines can be selected, for example, randomly. Specifically, in Fig. 9, for example, two lines 142A, 142B of the arc of the letter "P" lie within the predefined range of motion 162 of the pixel element 160. In the exemplary embodiment, line 142A is selected randomly for the pixel element 160, and accordingly, only the points 164 of this line are used to calculate the magnitude of the constant inclination in the first direction and the inclination range in the second direction.In an adjacent pixel element, the second line 142B with its associated points 166 can then be taken into account. With such a random selection, not just a single point is chosen at a time; rather, each selected line 142A, 142B covers a plurality of points 162 or 164, respectively. Since the size of the pixel elements 160 is below the resolving power of the eye, it is perfectly sufficient for a smooth representation of the motif 140 if the lines not selected in a pixel element 160 are taken into account in one of the adjacent pixel elements. In an alternative procedure illustrated in Fig. 10, which is suitable for any motif representation, the motif 140 is locally approximated by straight line elements in each case.For a pixel element 170, the points 176 of the motif representation that the pixel element can reach with its predefined range of motion 172 are approximated by a line element 174. This line element can be selected separately and differently for each pixel element 170. This approach works particularly well for motif sections that are straight or have only a slight curvature. With strong curvatures or even abrupt changes in direction of the motif representation, this approach can reach its limits, and the method described above is preferred. In a further development of the invention, it is possible to generate a changing image by partially nesting the pixel elements, in which different motif representations become visible from different viewing directions.The nesting can consist, in particular, of dividing the multitude of pixel elements into several subgroups, whereby the assignment to these subgroups can be carried out by a regular pattern, such as a checkerboard pattern, or by an irregular, for example, random distribution. The division into subgroups can be carried out such that each subgroup contains the same number of pixel elements, or such that individual groups are specifically provided with a higher / lower proportion of pixel elements. At least one of the aforementioned subgroups is covered with structures according to the invention. The other subgroups can be covered with structures according to the invention or with other optical structures.Crucially, each of the subgroups generates an optical effect under a different viewing range, so that when the security feature is tilted, an ideally abrupt transition / change occurs between the individual effects of the subgroups. This allows, for example, the creation of alternating images between two motif representations according to the invention, or between a motif representation according to the invention and another optical effect, such as a warping effect.

Claims

Patent claims 1. Optically variable security element for securing valuables, with a reflective surface area containing a plurality of reflective pixel elements which together display a motif with at least one curve representation depending on the viewing angle. This curve is visible as a target curve from a first viewing direction within a display area in a central position and moves away from the central position in different directions when the security element is tilted about two different predetermined axes within the display area, characterized in that – for each pixel element a parallel direction is defined parallel to the target curve in the central position and a normal direction is defined perpendicular to the target curve in the central position, – each pixel element has a first direction in the plane of the reflective surface area,along which the pixel element exhibits a constant inclination to the reflective surface area, except for any isolated discontinuities, wherein the constant inclination in the first direction is chosen depending on the distance of the respective pixel element to the specification curve, – each pixel element in the plane of the reflective surface area has a second direction perpendicular to the first direction, along which the pixel element exhibits an inclination to the reflective surface area, which in the entire surface area or in two or more sub-areas visible to the naked eye, each inclination is up to 1. The safety element according to claim 1, characterized in that the curve representation appears with a substantially uniform brightness in each of its different movement positions due to the formation of the pixel elements.

2. The safety element according to claim 1 or 2, characterized in that the inclination of the pixel elements along the second direction varies continuously except for isolated jump points, such that the pixel elements have a curved profile in the second direction. 4.A safety element according to claim 1 or 2, characterized in that the inclination of the pixel elements along the second direction is constant section by section, except for any isolated discontinuities, and assumes at least 3, preferably at least 5, different inclination values ​​within the predetermined inclination range. A safety element according to at least one of claims 1 to 4, characterized in that the predetermined inclination range has an angular extent between 10° and 90°, preferably between 15° and 40°, particularly preferably between 15° and 25°, and / or that the...

6. Predetermined inclination range is substantially symmetrical to the normal of the reflective surface area.

7. Safety element according to at least one of claims 1 to 5, characterized in that the pixel elements have an axis-symmetrical profile with respect to an axis in the normal direction, wherein the axis preferably runs through the center of the respective pixel element.

8. Safety element according to at least one of claims 1 to 6, characterized in that the constant inclination in the first direction increases or decreases monotonically, in particular strictly monotonically, with the distance of the respective pixel element from the predefined curve, preferably that the constant inclination in the first direction increases or decreases linearly with the distance of the respective pixel element from the predefined curve.A safety element according to at least one of claims 1 to 7, characterized in that the curve representation as a default curve shows at least one closed curve, in particular two concentric circular rings.

9. A safety element according to at least one of claims 1 to 8, characterized in that the motif contains at least a first and a second curve representation, which are visible from a first and second viewing direction within a first and second display area in a central position as a first and second default curve, respectively, wherein the two curve representations move in different, preferably opposite, directions when the safety element is tilted.

10. Optically variable security element for securing valuables, with a reflective surface area containing a multitude of reflective pixel elements which together create an optically variable motif representation, the appearance of which changes when the security element is tilted about two independent axes, characterized by the fact that – each pixel element has a first direction in the plane of the reflective surface area, along which the pixel element exhibits a constant, pixel-specific inclination to the plane of the reflective surface area, except for any isolated discontinuities, – each pixel element has a second direction in the plane of the reflective surface area, perpendicular to the first direction, along which the pixel element exhibits an inclination to the plane of the reflective surface area, which is constant in the entire surface area or in two or morevisible partial surface areas vary in a pixel-specific tilt range, except for any isolated discontinuities, – wherein the motif representation generated by the multitude of reflective pixel elements, or at least parts of the motif representation, move in different directions when the safety element is tilted about the two independent axes.

11. Safety element according to claim 10, characterized in that – the optically variable motif representation is formed by a plurality of line elements or is approximated by a plurality of line elements, – the constant inclination in the first direction and the inclination range in the second direction are selected for each pixel element to generate one of the aforementioned line elements of the motif representation, and – the line elements generated by the plurality of reflective pixel elements create an appearance in which the motif representation, or at least parts of the motif representation, move in different directions when the security element is tilted about the two independent axes.

12. Security element according to claim 10 or 11, characterized in that the motif representation, or at least parts of the motif representation, move parallactically when the security element is tilted about the two independent axes, so that the motif or the motif parts appear three-dimensional and seem to lie above and / or below the security element. 13.A security element according to at least one of claims 10 to 12, characterized in that the constant inclination in the first direction is selected depending on the distance of the respective pixel element to the generated line element, in particular that the constant inclination in the first direction increases or decreases monotonically, and in particular strictly monotonically, with the distance of the respective pixel element to the generated line element, preferably that the constant inclination in the first direction increases or decreases linearly with the distance of the respective pixel element to the generated line element.

14. A security element according to at least one of claims 10 to 13, characterized in that the motif representation is an elliptical ring. in particular, comprising an annulus that appears to float above or below the safety element, and that for the pixel elements contributing to the generation of the annulus, the first direction is in each case the radial direction towards the center of the elliptical ring or annulus, preferably that the elliptical ring or annulus is approximated by a group of line elements, and that for the pixel elements that generate the line elements of said group, the first direction is in each case the radial direction towards the center of the elliptical ring or annulus. 15.Security element according to at least one of claims 10 to 14, characterized in that the motif representation contains at least two elliptical rings, in particular two circular rings, which appear to float at different heights or depths, wherein preferably one ring appears to float above and one ring below the security element, and wherein the rings are concentric to each other from a specific viewing direction of the security element.

16. Security element according to at least one of claims 10 to 15, characterized in that adjacent pixel elements each have a similar first direction in certain areas, such that a substantially continuous progression of the first direction results in each of the aforementioned areas. 17.Security element according to at least one of claims 1 to 16, characterized in that the reflective surface area contains at least two subgroups, each with a plurality of pixel elements, and contains at least one coexistence area in which pixel elements from at least two of the aforementioned subgroups are located. – wherein the pixel elements are each covered with optical structures and the pixel elements of at least one subgroup participating in the coexistence area are configured according to one of claims 1 to 9 or according to one of claims 10 to 16, – wherein each of the subgroups participating in the coexistence area generates a partial motif visible from a visibility area and the visibility areas of the participating subgroups are not congruent, so that for each participating subgroup there is a partial visibility area in which the partial motifs generated by the other participating subgroups are not visible.

18. Security element according to at least one of claims 1 to 17, characterized in that the pixel elements have a dimension between 3 µm and 100 µm, preferably between 5 µm and 20 µm, and / or that the pixel elements have a maximum pitch that is between 0.5 µm and 10 µm, preferably between 1 µm and 5 µm. 19.Security element according to at least one of claims 1 to 18, characterized in that at least a portion of the pixel elements is provided with nanostructures and / or a coating, in particular with a reflective metal layer, a dielectric layer, a multilayer system, or a liquid crystal layer. Security element according to at least one of claims 1 to 19, characterized in that the reflective surface area comprises at least one metallized sub-area and one demetallized sub-area, wherein, in a preferred embodiment, at least one demetallized sub-area comprises etch support structures for increasing the etch rate of a coating.

21. Security document with a security element according to at least one of claims 1 to 20. 5

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