Security element with relief structure

Abstract

The invention relates to a security element (1) having at least one viewing angle-dependent indentation, comprising a flat carrier substrate (2) and at least one relief structure (3), wherein the relief structure (3) in incident light represents at least one viewing angle-dependent or viewing angle-independent motif and the relief structure (3) has structure-forming three-dimensional elements (4), characterised in that the relief structure (3) forms a free-form optical system and is subdivided into segments (5) of defined optical properties, in particular beam-optical properties, selected in particular from the group consisting of directional reflection, diffuse reflection, refraction, focusing, divergence and diffraction, wherein the at least one viewing angle-dependent indentation makes the motif appear in a first colour in at least a first viewing angle and in a second viewing angle, which is different from the first viewing angle, makes the motif appear in a second colour, which is different from the first colour.

Description

[0001] SECURITY ELEMENT WITH RELIEF STRUCTURE The invention relates to a security element, in particular for securities, security paper, or security objects, such as banknotes, ID cards, and credit cards, with at least one viewing-angle-dependent impression, comprising a flat carrier substrate and at least one relief structure, wherein the relief structure represents at least one viewing-angle-dependent or viewing-angle-independent motif in reflected light, and the relief structure has structure-forming three-dimensional elements. Security elements of the above-mentioned type are used to protect against counterfeiting of securities, such as banknotes, tickets, etc., security paper, and security documents, such as ID cards. The object of the present invention is to create a security element with increased forgery protection. At this point, it should be noted thatthat in the context of the invention, the term security element can refer to various types of security elements familiar to those skilled in the art. For example, security elements can be designed as security threads, security strips, security patches, and the like. Of course, other types of security elements known to those skilled in the art are also conceivable. This object is achieved by a security element of the type mentioned at the outset in that the relief structure forms a free-form optic and is divided into segments of defined optical properties, in particular ray-optical properties, in particular selected from the group of directed reflection, diffuse reflection, refraction, focusing, divergence, diffraction, wherein the at least one viewing angle-dependent impression makes the motif appear in a first color at at least a first viewing angle and in a second viewing angle different from the firstviewing angle in a second color, different from the first color. The solution according to the invention increases counterfeit security by the relief structure forming a free-form optic and being provided with a color-shift effect. With the solution according to the invention, an optical appearance can be achieved that is unique, characteristic, and easily recognizable to a viewer, but extremely difficult for a counterfeiter to imitate. Since the relief structure forms a free-form optic and is divided into segments with defined optical properties, it is thus highly complex,This makes replicating them considerably more difficult. With optical freeform surfaces, light striking the relief structures can be directed in virtually any direction, and they can be optimally tailored to the respective motif to be depicted. A combination with a color-shift effect makes the appearance characteristic and thus difficult to imitate. To produce relief structures, master structures are often transferred into a polymer using an embossing process. As is well known, this often involves multiple replications of the master. During these replication steps, errors in freeform optics could not yet be completely avoided. However, especially with freeform optics, a nearly perfect copy is required.to display the desired effects. The inventive subdivision of the relief structures into segments of defined optical properties has made error-free, or at least nearly error-free, replication of master structures with freeform optics possible. The segments contain the desired information of the corresponding freeform optics. This segmentation reduces the complexity of the structures without losing the optical properties. This facilitates the molding of the structures into polymer layers, for example, UV varnishes or thermally deformable polymers, for example, into the carrier substrate. Furthermore, the segmentation leads to region-specifically defined optical conditions, which in turn results in a higher light output and thus enables higher-contrast displays. The use of freeform optics allows for more precise, or at least almost error-free, replication of master structures using freeform optics compared to simpler optical elements such as micromirrors, lenses, prisms,etc., far more complex optical patterns can be generated, since a wide variety of ray-optical processes such as directed reflection, diffuse reflection, refraction, focusing, divergence, and diffraction can be realized in the smallest of spaces. The motif can represent a portrait, a landscape, an abstract geometric symbol, a logo, or an alphanumeric character and / or an icon and / or a code and / or a sequence of characters. In the context of the invention, the term segment refers to the sum of the elements contained therein and can comprise a single element or multiple elements. A structure-forming element is the smallest optically effective unit, e.g., a single micromirror. It can be advantageous for the viewing angle-dependent impression of the motif to be created by at least one reflective and / or optical effect, in particular an optically variable effect.causing coating is created. This further increases the security against counterfeiting. It may also be the case that the relief structure is at least partially provided with the coating. This further increases the security against counterfeiting. According to a further development, the coating may be designed as a color-shifting layer or comprise a color-shifting layer. This further increases the security against counterfeiting. Furthermore, it is conceivable that the coating is designed as an optical thin-film element in the form of an interference element. This further increases the security against counterfeiting. In a further embodiment, it may be provided that the coating contains color-shifting pigments, in particular interference pigments, or liquid crystal pigments, or that the coating contains metallic pigments and / or magnetic pigments and / or color pigments and / or dyes. It is also conceivable,that the coating has at least one layer enhancing the color-shift effect on a side facing away from a visible side. It may also be the case that sub-areas of at least some of the segments of the relief structure differ from one another at least by an average layer thickness of the coating. The average layer thickness is understood to be the layer thickness averaged across a segment. This further increases counterfeit security. Effect coatings such as color-shifting thin-film elements exhibit their optical effect depending on the layer thickness used. In freeform optics, the layer thicknesses constantly change due to the vapor deposition processes used, which causes adverse optical effects or promotes errors in color representation. Through segmentation, the structures in the segments can be designed in such a way thatthat the change in layer thickness does not lead to such adverse effects. Furthermore, the embossed structures can have sections that are differently inclined relative to a surface of the carrier film, wherein at least one image-forming coating with regions of different opacity is applied to the structures, and a layer thickness of the at least one coating depends on an inclination of the sections of the embossed structures. A variant in which the layer thickness of the coating increases with a decrease in the amount of the inclination of the sections and vice versa has proven particularly advantageous with regard to the production of the security element. According to a preferred embodiment of the invention, it can be provided that a color and / or brightness impression at a location on the coating in daylight depends on the layer thickness of the coating at this location. A preferred embodiment providesthat the optical effect layer or coating is formed as a thin-film element and has at least one absorber layer and at least one spacer layer. A conceivable structure of a thin-film element can have the following layer sequence: relief structure - spacer layer - absorber layer or relief structure - absorber layer - spacer layer. Furthermore, the optical effect layer or coating formed as a thin-film element can further comprise at least one reflective layer, wherein the at least one spacer layer is arranged between the at least one absorber layer and the at least one reflective layer. A conceivable structure of a thin-film element can have the following layer sequence: relief structure - reflective layer - spacer layer - absorber layer or relief structure - absorber layer - spacer layer - reflective layer. A further embodiment providesthat the reflection layer is applied to the relief structures, in particular printed and / or vapor-deposited. In addition, it can be advantageous if the coating producing an optical effect is printed and / or vapor-deposited onto the relief structures. A further embodiment is characterized in that the coating producing an optical effect has at least one liquid crystal layer, in particular a cholesteric liquid crystal layer. A further preferred embodiment provides that the security element, in addition to the coating producing an optical effect, has an optically non-linear layer or an optically non-linear layer and / or a layer containing fluorescent pigments and / or fluorescent substances.is present. Optically non-linear layers or layers, or materials forming these layers, are also referred to as IR upconverters or UV downconverters. These can be materials that exhibit a visible color under the influence of electromagnetic radiation outside the visible wavelength range of light. Such materials can be excited to emit visible light under these conditions, for example upon irradiation with infrared (IR) (λ > 780 nm) and / or ultraviolet (UV) light (λ < 380 nm). Furthermore, it is possible for the optical effect layer to contain photoluminescent pigments and / or photoluminescent substances that exhibit emission in the IR range when excited by electromagnetic radiation. Furthermore, a strongly absorbing dielectric material, for example germanium, can be used as an additional layer.be used. This additional layer can, for example, be applied to the color-shifting optical effect layer, which can be designed in particular in the form of a thin-film element. An alternative embodiment is characterized in that several elements and / or segments are arranged relative to one another in such a way that the arrangement of the structures forms several individual symbols, which symbols are included in the view of the image. This brings with it a further advantage, since this configuration contains an additional security feature. It can also be advantageous for the security element to be equipped with further color-shifting layers, in particular layers with color-shifting pigments or liquid crystals and / or with machine-readable features, wherein the machine-readable features are in particular magnetic codes, electrically conductive layers,electromagnetic wave-absorbing and / or re-emitting substances. A further possible and optionally alternative embodiment has the features that the security element has further or additional layers, which additional layers comprise, in particular, protective varnishes, heat-sealing varnishes, adhesives, primers and / or films. A preferred embodiment provides that the security element comprises a carrier substrate or a carrier layer made of a plastic, wherein in particular the plastic is formed from a translucent and / or thermoplastic plastic, and that the carrier layer preferably comprises at least one of the materials from the group polyimide (PI), polypropylene (PP), monoaxially oriented polypropylene (MOPP), biaxially oriented polypropylene (BOPP), polyethylene (PE), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyetherketone (PEK), polyethyleneimide (PEI), polysulfone (PSU), polyaryletherketone (PAEK),Polyethylene naphthalate (PEN), liquid crystalline polymers (LCP), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyamide (PA), polycarbonate (PC), cycloolefin copolymers (COC), polyoxymethylene (POM), acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), ethylene tetrafluoroethylene (ETFE), polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene hexafluoropropylene fluoro terpolymer (EFEP), cellulose- or lignin-based plastics, polyhydroxyalkanoates (PHA), thermoplastic starch (TPS), polylactic acid (PLA), polycaprolactone (PCL), polybutylene succinate (PBS), and polybutylene adipate terephthalate (PBAT) and / or comprises at least one recycled and / or biodegradable and / or marine degradable plastic and / or mixtures and / or copolymers of these materials or is made from at least one of these materials. It may also be advantageous ifthat the at least one absorber layer comprises at least one metallic material, in particular selected from the group of nickel, titanium, vanadium, chromium, cobalt, palladium, iron, tungsten, molybdenum, niobium, aluminum, silver, copper and / or alloys of these materials, or is made from at least one of these materials. According to a further development, it is possible for the at least one reflective layer to comprise at least one metallic material, in particular selected from the group consisting of silver, copper, aluminum, gold, platinum, niobium, tin, or nickel, titanium, vanadium, chromium, cobalt and palladium or alloys of these materials, in particular cobalt-nickel alloys or at least one high-index dielectric material with a refractive index of 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),Yttrium oxide (Y2O3), europium oxide (Eu2O3), iron oxides such as iron(II,III) oxide (Fe3O4) and iron(III) 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 (SiO), selenium trioxide (Se2O3), tin oxide (SnO2), tungsten trioxide (WO3), high-index organic monomers and / or high-index organic polymers or is made from at least one of these materials. Furthermore, a spacer layer can comprise at least one low-refractive dielectric material with a refractive index of less than or equal to 1.65, in particular selected from the group of aluminum oxide (Al2O3), metal fluorides, for example magnesium fluoride (MgF2), aluminum fluoride (AlF3), cerium fluoride (CeF3), sodium aluminum fluorides (e.g. Na3AlF6 or Na5Al3F, 14 ), silicon oxide (SiO x), silicon dioxide (SiO2), neodymium fluoride (NdF3), lanthanum fluoride (LaF3), samarium fluoride (SmF3), barium fluoride (BaF2), calcium fluoride (CaF2), lithium fluoride (LiF), low-refractive organic monomers and / or low-refractive organic polymers or at least one high-refractive dielectric material with a refractive index greater than 1.65, in particular selected from the group zinc sulfide (ZnS), zinc oxide (ZnO), titanium dioxide (TiO2), carbon (C), indium oxide (In2O3), indium tin oxide (ITO), tantalum pentoxide (Ta2O5), cerium oxide (CeO2), yttrium oxide (Y2O3), europium oxide (Eu2O3), iron oxides such as iron(II,III) oxide (Fe3O4) and iron(III) oxide (Fe2O3), hafnium nitride (HfN), hafnium carbide (HfC), hafnium oxide (HfO2), lanthanum oxide (La2O3), magnesium oxide (MgO), neodymium oxide (Nd2O3), praseodymium oxide (Pr6O 11), samarium oxide (Sm2O3), antimony trioxide (Sb2O3), silicon carbide (SiC), silicon nitride (Si3N4), silicon monoxide (SiO), selenium trioxide (Se2O3), tin oxide (SnO2), tungsten trioxide (WO3), high-refractive organic monomers and / or high-refractive organic polymers or be made from at least one of these materials. Furthermore, it can be provided that the coating is or comprises a metal layer and / or metal effect layer, in particular a metal effect paint and / or a metal effect varnish and / or a metal effect ink and / or a metallic material, in particular selected from the group consisting of silver, copper, aluminium, gold, platinum, niobium, tin, or nickel, titanium, vanadium, chromium, cobalt and palladium or alloys of these materials, in particular cobalt-nickel alloys. The security against counterfeiting can be further increased by the fact that the coating is a partial coating and the coating creates a portrait,a landscape, an abstract geometric symbol, a logo, an alphanumeric character, and / or an icon, and / or a code, and / or a sequence of characters is depicted. The relief structures can be embossed directly into the carrier substrate or into the carrier layer. For example, by heating the carrier layer and embossing the structures using an embossing tool, such as an embossing roller. Another alternative possibility would be to provide a separate additional layer, in particular an embossing lacquer layer, to accommodate the structures. The additional layer can be applied directly to the carrier layer. In both variants, the structures can be introduced using a molding device or a molding element in an embossing process. Furthermore, it is conceivable that subregions of at least some of the segments of the relief structure have the same average coating thickness. A further development can providethat a local layer thickness of the coating depends on the shape and / or size and / or orientation of the elements. According to a further development, each segment may form a pixel, wherein each segment preferably comprises at least one structure-forming element or several structure-forming elements. This further increases the security against counterfeiting. A pixel is the smallest unit perceivable with the naked eye. A group of elements becomes visible to the naked eye in a pixel. In addition, it may also be the case that the structure-forming elements comprise reflective and / or refractive and / or diffractive and / or micromirrors and / or structures forming at least one hologram and / or microlenses. It is also conceivable that the structure-forming elements are achromatic elements. In addition, it may bethat the relief structure is formed asymmetrically with respect to a rotation about an axis running normal to a plane of the carrier substrate and a translation parallel to the plane of the carrier substrate. This further increases the security against counterfeiting. In addition, it may be that a sequence of segments along a direction parallel to the carrier substrate has a constant or varying spatial frequency. This further increases the security against counterfeiting. In addition, it may be that at least one segment or each segment of at least some of the segments forms a free-form optic. A further embodiment may provide that at least some of the segments are formed rotationally symmetrically and / or translationally symmetrically to one another. In a further embodiment, it may be provided,that the segments have identical or different outline shapes. This further increases the security against counterfeiting. Within the segments, the elements can exhibit irregularities in terms of shape, size, etc. The segments themselves can be arranged regularly or irregularly, depending on how this is advantageous for the representation of the optical effect. It is also conceivable that adjacent segments are separated from one another by a segment boundary free of structure-forming elements or by a segment boundary containing elements of a different structure and size than those located within the adjacent segments. This further increases the security against counterfeiting. In a further development, it can also be providedthat the elements of a segment are at least partially of the same and / or different shape and / or size and / or at least partially of the same and / or different orientation. This further increases the security against counterfeiting. It is also advantageous if the segments are arranged regularly and / or irregularly at least in a partial area of ​​the relief structure. This further increases the security against counterfeiting. For a better understanding of the invention, it is explained in more detail with reference to the following figures. They each show, in a highly simplified, schematic representation: Fig. 1 shows a security element in plan view, Fig. 2 shows a detailed view of Fig. 1, Fig. 3 shows a possible layer structure of a security element, Fig. 4 shows another security element in plan view, Fig. 5 shows another possible layer structure of a security element. By way of introduction,that in the variously described embodiments, identical parts are provided with identical reference symbols or identical component designations, whereby the disclosures contained in the entire description can be applied analogously to identical parts with identical reference symbols or identical component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these positional information is to be applied analogously to the new position in the event of a change in position. At this point, it should be noted that the phrase "a layer is applied to something" is to be understood to mean that the layer can be applied directly, or that one or more intermediate layers can be located between the applied layer and that to which the layer is applied. At this point, it should also be noted thatthat one or more intermediate layers can be arranged between the layers described in this document. It is therefore not absolutely necessary for the described layers to contact one another. Furthermore, it should be noted that the term layer in this document is to be understood to mean that a layer can also be constructed from several sub-layers. As far as possible, the figures are described below in a synopsis to avoid unnecessary repetition. Figs. 1 and 4 show a security element 1 with a flat carrier substrate 2 and at least one relief structure 3 in plan view, wherein the relief structure 3 represents at least one motif in reflected light and the relief structure 3 has structure-forming three-dimensional elements 4. Fig. 2 is a detailed view of Fig. 1 and shows, by way of example, an element 4 formed in one of the segments 5. In this case,that the relief structure 3 forms a free-form optic and is divided into segments 5 of defined optical properties, in particular ray-optical properties, in particular selected from the group of directed reflection, diffuse reflection, refraction, focusing, divergence, diffraction, wherein the at least one viewing angle-dependent impression makes the motif appear in a first color at at least a first viewing angle and in a second viewing angle different from the first viewing angle, in a second color different from the first color. It may be that each segment 5 forms a pixel, wherein each segment 5, for example, as shown roughly schematically in Fig. 2, preferably comprises at least one structure-forming element 4 or, not shown figuratively, comprises several structure-forming elements 4. It may be that the structure-forming elements 4 are achromatic elements. It is conceivable,that the relief structure 3 is formed asymmetrically with respect to a rotation about an axis running normal to a plane of the carrier substrate 2 and a translation parallel to the plane of the carrier substrate 2. The segments 5 may have identical outline shapes. This is shown by way of example in Fig. 1 using a checkerboard-like grid. Of course, any other outline shape is also conceivable. Fig. 4 shows that the security element 1 may also have segments 5 with different outline shapes. For example, one segment 5 may have a rectangular outline and another segment 5 may have a triangular outline. This, in turn, is representative of a multitude of conceivable outline shapes. While Fig. 1 shows that the segments 5 may be directly adjacent to one another and may be separated by segment boundaries 7, Fig. 4 showsthat the segments 5 can also be spaced apart from one another. Of course, combinations of these variants are also conceivable. A sequence of segments 5 can have a constant or varying spatial frequency along a direction parallel to the carrier substrate 2. In Fig. 1, the segments 5, for example when viewed from left to right, have a constant spatial frequency, while the segments 5 in Fig. 4 have a varying spatial frequency. The distance between the lines or the segment boundaries 7 corresponds to the spatial frequency. As already described, it can also be the case that neighboring segments 5 are separated from one another by a segment boundary 7 that is free of structure-forming elements 4 or by a segment boundary 7 that has elements 4 of a different structure and size than those elements 4 lying within the neighboring segments 5. It can bethat the elements 4 of a segment 5 are formed at least partially of similar and / or different shape and / or size and / or at least partially of the same and / or different orientation. Similar segments 5 are shown in Fig. 1, while Fig. 4 shows, by way of example, segments 5 of different shape and size. It is also conceivable that the segments 5 are arranged regularly and / or irregularly, at least in a partial area of ​​the relief structure 3. It may also be the case that the relief structure 3 is at least partially provided with at least one reflective coating 6 and / or coating 6 producing an optical effect, in particular an optically variable effect. This is shown, for example, in a roughly schematic manner in the sectional view of a security element 1 according to Fig. 3. Figs. 3 and 5 show a security element 1 with a flat carrier substrate 2 and at least one relief structure 3,wherein the relief structure 3 represents at least one motif in reflected light and the relief structure 3 has structure-forming three-dimensional elements 4. It is provided that the relief structure 3 forms a free-form optic and is divided into segments 5 of defined optical properties, in particular ray-optical properties, in particular selected from the group of directed reflection, diffuse reflection, refraction, focusing, divergence, and diffraction. Fig. 3 shows an embodiment of a security element 1 in which the relief structure 3 has a substantially planar surface. Fig. 5 shows an embodiment of a security element 1 in which the relief structure 3 has a substantially non-planar surface. Although not explicitly shown, it may also be conceivable and advantageous in the embodiment according to Fig. 5,if the relief structure 3 is at least partially provided with at least one reflective coating 6 and / or one that produces an optical effect, in particular an optically variable effect. It may be that the viewing angle-dependent impression of the motif is generated by at least one reflective coating 6 and / or one that produces an optical effect, in particular an optically variable effect. It is conceivable that the relief structure 3 is at least partially provided with the coating 6. The coating 6 can be designed as a color-shifting layer or comprise a color-shifting layer. It may be that the coating 6 producing the optical effect is formed by an optical thin-film element in the form of an interference element. In Fig. 3, this coating 6 is partially implemented. However, a full-surface coating 6 of the relief structures 3 is also conceivable. It may bethat the optical effect layer or coating 6 is formed as a thin-film element and has at least one absorber layer 9 and at least one spacer layer 10. Furthermore, the optical effect layer or coating 6 formed as a thin-film element can further comprise at least one reflective layer, wherein the at least one spacer layer 10 is arranged between the at least one absorber layer 9 and the at least one reflective layer. This is not shown in the figure. It is also conceivable that the reflective layer is applied to the relief structures 3, in particular printed and / or vapor-deposited. One possible embodiment can be formed in that the optical effect layer or coating 6 contains color-shifting pigments, in particular interference pigments, or liquid crystal pigments. Furthermore, it can be advantageousthat a color shift effect occurs in the coating 6 producing an optical effect upon movement of the light source and / or change of the viewing angle. The coating 6 producing an optical effect may comprise metallic pigments and / or magnetic pigments and / or color pigments and / or dyes. It may be that the coating 6 producing an optical effect has at least one layer enhancing the color shift effect on a side facing away from a visible side. Furthermore, it may be advantageous if the coating 6 producing an optical effect is printed and / or vapor-deposited onto the relief structures 3. It may also be that the coating 6 producing an optical effect has at least one liquid crystal layer, in particular a cholesteric liquid crystal layer. It is also conceivablethat the security element 1, in addition to the coating 6 producing an optical effect, contains an optically non-linear layer or an optically non-linear layer and / or a layer containing fluorescent pigments and / or fluorescent substances. Furthermore, a highly absorbent dielectric material, for example germanium, can be used as an additional layer. This additional layer can, for example, be applied to the color-shifting optical effect layer or to the coating 6, which can in particular be designed in the form of a thin-film element. An alternative embodiment is characterized in that several are arranged relative to one another in such a way that, by means of the arrangement of the relief structures 3, several individual symbols are formed, which symbols are contained in the view of the image. Furthermore, the security element 1 can be provided with further color-shifting layers,in particular layers with color-shifting pigments or liquid crystals and / or with machine-readable features, wherein the machine-readable features are in particular magnetic coding, electrically conductive layers, electromagnetic wave-absorbing and / or re-emitting substances. It is also conceivable for the security element 1 to have further or additional layers, which additional layers in particular comprise protective layers 8 such as protective varnishes, heat-sealing varnishes, adhesives, primers, and / or films. In Figs. 3 and 5, an optional protective layer 8 is indicated by dashed lines. The security element 1 may comprise a carrier substrate 2 or a carrier layer made of a plastic, wherein the plastic is in particular formed from a translucent and / or thermoplastic plastic.and that the carrier layer preferably comprises at least one of the materials from the group polyimide PI, polypropylene PP, monoaxially oriented polypropylene MOPP, biaxially oriented polypropylene BOPP, polyethylene PE, polyphenylene sulfide PPS, polyether ether ketone, PEEK polyether ketone PEK, polyethylene imide PEI, polysulfone PSU, polyarylether ketone PAEK, polyethylene naphthalate PEN, liquid crystalline polymers LCP, polyester, polybutylene terephthalate PBT, polyethylene terephthalate PET, polyamide PA, polycarbonate PC, cycloolefin copolymers COC, polyoxymethylene POM, acrylonitrile butadiene styrene ABS, polyvinyl chloride PVC, ethylene tetrafluoroethylene ETFE, polytetrafluoroethylene PTFE, polyvinyl fluoride PVF, polyvinylidene fluoride PVDF, ethylene tetrafluoroethylene hexafluoropropylene fluoro terpolymer EFEP, cellulose or Lignin-based plastics, polyhydroxyalkanoates PHA, thermoplastic starch TPS, polylactic acid PLA, polycaprolactone PCL, polybutylene succinate PBS,and polybutylene adipate terephthalate PBAT and / or at least one recycled and / or biodegradable and / or marine degradable plastic and / or mixtures and / or copolymers of these materials or is made from at least one of these materials. It may also be advantageous for the at least one absorber layer 9 to comprise at least one metallic material, in particular 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, or to be made from at least one of these materials. According to a further development, it is possible for the at least one reflective layer to comprise at least one metallic material, in particular selected from the group consisting of silver, copper, aluminum, gold, platinum, niobium, tin, or nickel, titanium, vanadium, chromium, cobalt and palladium or alloys of these materials.in particular cobalt-nickel alloys or at least one high-index dielectric material with a refractive index greater than 1.65, in particular selected from the group zinc sulfide ZnS, zinc oxide ZnO, titanium dioxide TiO2, carbon C, indium oxide In2O3, indium tin oxide ITO, tantalum pentoxide Ta2O5, cerium oxide CeO2, yttrium oxide Y2O3, europium oxide Eu2O3, iron oxides such as iron II, III oxide Fe3O4 and iron III oxide Fe2O3, hafnium nitride HfN, hafnium carbide HfC, hafnium oxide HfO2, lanthanum oxide La2O3, magnesium oxide MgO, neodymium oxide Nd2O3, praseodymium oxide Pr6O, 11, samarium oxide Sm2O3, antimony trioxide Sb2O3, silicon carbide SiC, silicon nitride Si3N4, silicon monoxide SiO, selenium trioxide Se2O3, tin oxide SnO2, tungsten trioxide WO3, high-index organic monomers and / or high-index organic polymers or is made from at least one of these materials. Furthermore, a spacer layer 10 can comprise at least one low-index dielectric material with a refractive index less than or equal to 1.65, in particular selected from the group aluminum oxide Al2O3, metal fluorides, for example magnesium fluoride MgF2, aluminum fluoride AlF3, cerium fluoride CeF3, sodium aluminum fluorides, e.g. Na3AlF6 or Na5Al3F 14 , silicon oxide SiO x, silicon dioxide SiO2, neodymium fluoride NdF3, lanthanum fluoride LaF3, samarium fluoride SmF3, barium fluoride BaF2, calcium fluoride CaF2, lithium fluoride LiF, low-refractive organic monomers and / or low-refractive organic polymers or at least one high-refractive dielectric material with a refractive index greater than 1.65, in particular selected from the group zinc sulfide ZnS, zinc oxide ZnO, titanium dioxide TiO2, carbon C, indium oxide In2O3, indium tin oxide ITO, tantalum pentoxide Ta2O5, cerium oxide CeO2, yttrium oxide Y2O3, europium oxide Eu2O3, iron oxides such as iron II, III oxide Fe3O4 and iron III 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 SiO, selenium trioxide Se2O3, tin oxide SnO2, tungsten trioxide WO3,high-refractive-index organic monomers and / or high-refractive-index organic polymers or be made of at least one of these materials. Furthermore, it can be provided that the coating 6 is or comprises a metal layer and / or metal effect layer, in particular a metal effect paint and / or a metal effect varnish and / or a metal effect ink and / or a metallic material, in particular selected from the group consisting of silver, copper, aluminum, gold, platinum, niobium, tin, or nickel, titanium, vanadium, chromium, cobalt, and palladium, or alloys of these materials, in particular cobalt-nickel alloys. It can be that the coating 6 is a partial coating, and the coating can create a portrait, a landscape, an abstract geometric symbol,A logo or an alphanumeric character and / or an icon and / or a code and / or a sequence of characters is depicted. The relief structures 3 can be embossed directly into the carrier substrate 2 or into the carrier layer, as shown in Fig. 3 and Fig. 5. For example, by heating the carrier substrate 2 and embossing the relief structures 3 using an embossing tool, such as an embossing roller. Another alternative possibility, not shown in the figure, would be to provide a separate additional layer, in particular an embossing lacquer layer, to accommodate the relief structures 3. The additional layer can be applied directly to the carrier substrate 2. In both variants, the relief structures 3 can be introduced using a molding device or a molding element in an embossing process. It is conceivable herethat subregions of at least some of the segments 5 of the relief structure 3 differ from one another at least by an average layer thickness of the coating 6. In addition, it may be that subregions of at least some of the segments 5 of the relief structure 3 have the same average layer thickness of the coating 6. Furthermore, it may be that a local layer thickness of the coating 6 depends on the shape and / or size and / or orientation of the elements 4. It may also be that at least one segment 5 or each segment 5 of at least some of the segments 5 forms a free-form optic. Furthermore, it is conceivable that at least some of the segments 5 are rotationally symmetrical and / or translationally symmetrical to one another. All information on value ranges in this description is to be understood as including any and all subranges thereof, e.g., the information 1 to 10 is to be understood as including all subranges,starting from the lower limit of 1 and the upper limit of 10, i.e., all sub-areas begin with a lower limit of 1 or greater and end at an upper limit of 10 or less, e.g., 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10. For the sake of clarity, it should be noted that, for a better understanding of the structure, some elements have been shown not to scale and / or enlarged and / or reduced. As an introduction, it should be mentioned that the layer structure, as well as the arrangement of further layers, depends on the type of application of the security element to a security article, since the side of the security element to be viewed after application is crucial. Thus, the visible side can be viewed from above, as shown in the figures, but it is also possible to view the security element from below, e.g., through a support.

[0002] Reference symbol list Security element Carrier substrate Relief structure Element Segment Coating Segment boundary Protective layer Absorber layer Spacer layer

Claims

Patent claims 1. Security element (1) with at least one viewing angle-dependent impression, comprising a planar carrier substrate (2) and at least one relief structure (3), wherein the relief structure (3) in reflected light represents at least one viewing angle-dependent or viewing angle-independent motif and the relief structure (3) has structure-forming three-dimensional elements (4), characterized in that the relief structure (3) forms a free-form optic and is divided into segments (5) of defined optical properties, in particular ray-optical properties, in particular selected from the group of directed reflection, diffuse reflection, refraction, focusing, divergence, diffraction, wherein the at least one viewing angle-dependent impression makes the motif appear in a first color at least at a first viewing angle and in a second viewing angle different from the first viewing angle in a second,different from the first color.

2. Security element (1) according to claim 1, characterized in that the viewing angle-dependent impression of the motif is generated by at least one reflective and / or optical effect-producing coating (6), in particular an optically variable effect.

3. Security element (1) according to claim 2, characterized in that the relief structure (3) is at least partially provided with the coating (6).

4. Security element (1) according to claim 2 or 3, characterized in that the coating (6) is designed as a color-shifting layer or comprises a color-shifting layer.

5. Security element (1) according to one of claims 2 to 4, characterized in that the coating (6) is designed by an optical thin-film element in the form of an interference element.

6. Security element (1) according to one of claims 2 to 5, characterized in thatthat the coating (6) contains color-shifting pigments, in particular interference pigments, or liquid crystal pigments, or that the coating (6) contains metallic pigments and / or magnetic pigments and / or color pigments and / or dyes., 7. Security element (1) according to one of claims 2 to 6, characterized in that the coating (6) has at least one layer enhancing the color-shift effect on a side facing away from a visible side.

8. Security element (1) according to one of claims 2 to 7, characterized in that partial regions of at least some of the segments (5) of the relief structure (3) differ from one another at least by an average layer thickness of the coating (6).

9. Security element (1) according to one of claims 2 to 8, characterized in that partial regions of at least some of the segments (5) of the relief structure (3) have the same average layer thickness of the coating (6).

10. Security element (1) according to one of claims 2 to 9, characterized in that a local layer thickness of the coating (6) depends on the shape and / or size and / or orientation of the elements (4). 11.Security element (1) according to one of claims 1 to 10, characterized in that each segment (5) forms a pixel, wherein each segment (5) preferably comprises at least one structure-forming element (4) or a plurality of structure-forming elements (4).

12. Security element (1) according to one of claims 1 to 12, characterized in that the relief structure (3) is formed asymmetrically with respect to a rotation about an axis running normal to a plane of the carrier substrate (2) and a translation parallel to the plane of the carrier substrate (2).

13. Security element (1) according to one of claims 1 to 5, characterized in that a sequence of segments (5) along a direction parallel to the carrier substrate (2) has a constant or varying spatial frequency. 14.Security element (1) according to one of claims 1 to 13, characterized in that at least one segment (5) or each segment (5) of at least some of the segments (5) forms a free-form optic.

15. Security element (1) according to one of claims 1 to 14, characterized in that at least some of the segments (5) are rotationally symmetrical and / or translationally symmetrical to one another.

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