OPTICALLY VARIABLE SAFETY ELEMENT WITH REFLECTIVE SURFACE AREA

Description

[0001] The invention relates to an optically variable security element for protecting valuables with a reflective surface area. The invention also relates to a method for producing such a security element and a data carrier equipped with such a security element.

[0002] Data storage media, such as valuables or identification documents, as well as other valuable items such as branded goods, are often provided with security elements for security purposes. These elements allow verification of the authenticity of the data storage media and also serve as protection against unauthorized reproduction. These security elements can, for example, take the form of a security thread embedded in a banknote, a cover foil for a banknote with a hole, an applied security strip, a self-supporting transfer element, or even a feature area applied directly to a valuable document.

[0003] Security elements with a viewing-angle-dependent or three-dimensional appearance play a special role in authenticity assurance, as these cannot be reproduced even with the most modern copying machines. For this purpose, the security elements are equipped with optically variable elements that convey a different image impression to the viewer at different viewing angles, for example, displaying a different color or brightness impression and / or a different graphic motif depending on the viewing angle. In the prior art, optically variable effects include, for example, motion effects, pump effects, depth effects, or flip effects, which are realized using holograms, microlenses, or micromirrors.

[0004] Some time ago, optically variable security elements were proposed which have two relief structures arranged at different heights and each provided with a colour coating (see WO 2020 / 011390 A1, WO 2020 / 011391 A1 and WO 2020 / 011391 A2).

[0005] DE 10 2018 009912 A1 describes a method for producing an optically variable security element, in which a non-metal coating is selectively lifted from a higher relief structure. WO 97 / 19820 A1 relates to an optical data carrier with two diffractive relief structures at different heights. DE 10 2014 019088 A1 relates to an optically variable see-through security element with an optically variable surface pattern that, when viewed through, exhibits a colored appearance with a viewing-angle-dependent multicolored color change. DE 10 2018 103236 A1 discloses an optically variable security element comprising a layer with transmission and blocking regions, which is used as a mask for the lithographic fixation of a precisely fitting color pattern.

[0006] Based on this, the invention is based on the object of proposing a generic optically variable security element with an attractive appearance and high protection against counterfeiting, which should also be simple and cost-effective to produce. In particular, the security element should be capable of being equipped with a multicolored reflective surface area that displays at least two different colored appearances that can be recognized from different viewing directions.

[0007] This object is achieved by the features of the independent claim. Further developments of the invention are the subject of the dependent claims.

[0008] To achieve the stated object, the invention includes an optically variable security element with a reflective surface area, which can be used in particular for protecting valuables. The surface area of ​​the security element defines a plane and a z-axis perpendicular to the surface.

[0009] The reflective surface area contains a planar, transmissive, particularly reflective, primary structure formed by a printed or embossed pattern. The planar primary structure is covered by a secondary structure in the form of an embossed lacquer layer containing an embossed relief pattern. It also has low transmittance for crosslinking radiation, particularly UV radiation, in blocking regions and high transmittance for crosslinking radiation, particularly UV radiation, in transmitting regions.

[0010] The crosslinking radiation is preferably UV radiation, but electron beams or high-energy visible radiation in the blue or violet spectral range can also be used. The crosslinking radiation serves to crosslink and thus harden a crosslinkable layer of the security element, in particular the wash-on ink described in more detail below.

[0011] The security element further contains a reflection-enhancing coating that coats the secondary structure and, if the transmission regions are formed by cutouts in the secondary structure, also the primary structure in the transmission regions. The reflection-enhancing coating advantageously follows the relief pattern of the relief structure of the secondary structure embossed lacquer layer. If the transmission regions are formed by material regions of the secondary structure, the reflection-enhancing coating can also directly represent a coating of the secondary structure.

[0012] On the side of the planar primary structure opposite the secondary structure, a cross-linked, translucently colored wash-on ink is arranged congruently with the transmission areas, imparting a color effect to the primary structure in the transmission areas. The wash-on ink can be applied directly to the primary structure or can be separated from it by one or more translucent intermediate layers, in particular a transparent carrier film.

[0013] In a preferred embodiment, the transmission regions of the secondary structure are formed by cutouts in the secondary structure. In this variant of the invention, the secondary structure therefore only partially covers the primary structure, with the material regions of the secondary structure forming the aforementioned blocking regions with low permeability for the crosslinking radiation, and the cutout regions of the secondary structure forming the transmission regions with high permeability.

[0014] In another, equally advantageous embodiment, the transmission regions and the blocking regions of the secondary structure are each formed by material regions of the secondary structure that differ in their permeability to the cross-linking radiation. For example, the blocking regions can contain an absorber for the cross-linking radiation, while the transmission regions contain no absorber or a small amount of absorber. The blocking regions and the transmission regions can also differ in their color, with the color of the blocking regions causing a higher absorption of the cross-linking radiation than the color of the transmission regions. The transmission regions can also be formed in an otherwise homogeneous material by thinner material regions of the secondary structure and thus have a higher permeability to the cross-linking radiation.

[0015] At least in the blocking areas of the secondary structure, an absorber for the crosslinking radiation, in particular a UV absorber, is advantageously provided. As mentioned, the reflection-enhancing coating advantageously follows the relief pattern of the relief structure of the secondary structure embossing lacquer layer, at least in the blocking areas.

[0016] In a particularly preferred embodiment, the primary structure is in the form of a further embossing lacquer layer provided with an embossed relief structure that is preferably designed differently from the relief structure of the secondary structure embossing lacquer layer. It can further be provided that the reflection-enhancing coating follows the relief profile of the further relief structure of the primary structure in transmission regions of the secondary structure formed by recesses. Particularly advantageously, the reflection-enhancing coating then forms a joint coating of the primary and secondary structure and follows the relief profile of the relief structure of the secondary structure embossing lacquer layer in the blocking regions and the relief profile of the further relief structure of the primary structure in transmission regions of the secondary structure formed by recesses.

[0017] If both the primary structure and the secondary structure are formed by embossing lacquer layers with an embossed relief structure, the two embossed relief structures are arranged at different height levels, particularly in the z-direction, forming a lower and a higher relief structure. The distance between the different height levels in the z-direction is typically only a few micrometers, in particular between 1 µm and 10 µm, preferably between 3 µm and 7 µm.

[0018] Although this is currently preferred, the primary structure does not necessarily have to be formed in the form of an additional embossing lacquer layer. Rather, the primary structure can also be formed, for example, by a reflective or transmissive imprint, which can be created using conventional printing processes such as offset printing, letterpress, indirect letterpress, flexographic printing, gravure printing, or screen printing, as well as digital printing processes such as inkjet printing, laser printing, thermal sublimation printing, thermal transfer printing, or indirect inkjet printing such as nanoprinting.

[0019] The primary structure can be colorless or colored, and it can be transparent or translucent. A transparent or translucent primary structure is transmissive and can also be reflective, for example, when high-index materials are used. The primary structure can also contain luminescent substances, IR-absorbing substances, magnetic substances, or other machine-readable feature substances.

[0020] The secondary structure embossing lacquer layer is advantageously colored in a translucent manner, preferably with a color effect that differs from the color effect of the translucently colored wash color.

[0021] The wash dye used is preferably water-soluble in the uncrosslinked state and water-insoluble in the crosslinked state. In general, a suitable crosslinkable wash dye can be formulated as follows: Crosslinking of the wash dye can be enabled by adding a photoinitiator or a photoinitiator mixture. An essential component of the wash dye is a binder that is solid at room temperature, soluble in the solvent mixture or solvent used, particularly in water, and also soluble again during the washing process and can preferably be crosslinked in conjunction with the other components. Examples of binders that can be used according to the invention are hydroxyethylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, casein, carboxymethylcellulose, starch, polyvinyl alcohol, polyacrylic acid, or polyethylene glycol.

[0022] Crosslinking of the wash-on paint can be promoted by using a multifunctional reactive thinner. This reactive thinner must be compatible with the solvent or solvent mixture used, especially water. Water compatibility can be adjusted by varying the degree of ethoxylation.

[0023] A soluble dye or a finely dispersed pigment can be used to give the wash paint a translucent color.

[0024] Advantageously, the wash ink is windable after physical drying (roll to roll process), block-free at room temperature and has sufficient solubility in at least one solvent, especially in water.

[0025] The reflection-enhancing coating mentioned is advantageously formed by a metallization, a high-refractive coating, a thin-film element with a color-shift effect or a cholesteric liquid crystal layer.

[0026] In an advantageous embodiment, the relief structure of the secondary structure and / or optionally the relief structure of the primary structure are formed by micromirror arrangements with directionally reflecting micromirrors, in particular with non-diffractive mirrors, and preferably with flat mirrors, concave mirrors and / or Fresnel-type mirrors. The lateral dimensions of the micromirrors are expediently below 50 µm, advantageously below 20 µm, preferably approximately 10 µm, i.e. between 7 µm and 13 µm. On the other hand, the lateral dimensions of the micromirrors can also be above 2 µm, in particular above 3 µm or even above 5 µm. The pitch of the micromirrors is preferably less than 10 µm, more preferably less than 5 µm.

[0027] In principle, other embossed relief structures, in particular Fresnel lenses, concave mirrors, hologram structures, nanostructures, or diffractive blazed gratings, can be used instead of micromirrors. Achromatic diffraction gratings, so-called matte structures, which essentially reflect white light, can also be used advantageously. To create bright colors, the relief structures can also have subwave structures, in particular subwavelength gratings, which also contribute to the coloring.

[0028] If the security element contains at least two relief structures, a first of the relief structures is advantageously designed and configured to show a first optically variable effect in a first color, and a second of the relief structures is designed and configured to show a second optically variable effect in a second, different color.

[0029] In the blocking areas, the wash color has been removed, particularly to the extent that it no longer provides any color effect, or has been removed completely.

[0030] In an advantageous embodiment, the blocking regions and the transmission regions are formed, at least in a partial region of the surface region, as a regular or irregular grid with grid elements (blocking regions) and grid spaces (transmission regions), wherein the dimensions of the grid elements and grid spaces in one or both lateral directions are below 140 µm, preferably between 20 µm and 100 µm, in particular between 20 µm and 60 µm.

[0031] In the resulting grid areas, the security element advantageously displays an appearance when tilted or the viewing direction is changed accordingly, suddenly jumping from a first to a second appearance (or from the second to the first appearance when tilted back). This involves a simultaneous and seamless change in the depicted motif (e.g., a value number or a coat of arms) and color (e.g., magenta, green, or blue) without any intermediate or transitional stage. Such a seamless transition between two different motifs with two different colors is referred to as a binary color and effect change.

[0032] The grid advantageously has a constant area coverage by the grid elements, which is expediently between 30% and 70%, preferably between 40% and 60%, in particular approximately 50%.

[0033] Alternatively or in addition to the formation of a grid, it is provided that the blocking regions and the transmission regions form an effect region at least in a partial region of the surface region, in which the blocking regions and / or the transmission regions have lateral dimensions of more than 140 µm.

[0034] In this effect area, the security element preferably displays two different effects (e.g., a three-dimensional motif and a moving effect such as a moving bar) that appear in two different colors. The areas of different color impression and different effects are precisely matched to each other, which is also referred to as color-to-effect registration.

[0035] In this embodiment, at least one blocking region and / or at least one transmission region is advantageously formed with lateral dimensions of more than 250 µm, preferably of more than 500 µm and in particular of more than 1 mm.

[0036] In an advantageous embodiment, the reflection-enhancing coating is applied over the entire surface and without any recesses. Alternatively, negative markings can also be provided in the security element, formed by recesses in the reflection-enhancing coating. The negative markings can, for example, be text, symbols, or value numbers. The negative markings can be provided only in the blocking areas or only in the transmission areas, or they can cover both areas.

[0037] The reflective surface area of ​​the security element can also be combined with other security features, for example with holograms, in particular true-color holograms, with subwavelength gratings or other subwavelength structures, with micromirror arrangements without diffractive gratings, or with machine-readable security features based on special material properties, such as electrical conductivity, magnetic properties, luminescence, fluorescence or the like.

[0038] The optically variable security element may contain additional layers, such as protective, covering, or additional functional layers, primer layers, or heat-sealing lacquer layers. However, these do not represent the essential elements of the present invention and are therefore not described in detail.

[0039] The invention also includes a data carrier with a security element of the type described. The data carrier can be, in particular, a value document, such as a banknote, in particular a paper banknote, a polymer banknote or a foil composite banknote, a share, a bond, a certificate, a voucher, a cheque, a high-value admission ticket, but also an identification card, such as a credit card, a bank card, a cash payment card, an authorization card, an identity card or a passport personalization page.

[0040] The invention further includes a method for producing an optically variable security element, in particular one of the security elements already described, in which a carrier is provided, the surface area of ​​which defines a z-axis perpendicular thereto, the carrier is provided in one surface area with a planar, transmissive primary structure which is formed by a printed or embossed structure, and the planar primary structure is covered by a secondary structure in the form of an embossing lacquer layer which contains an embossed relief structure and which has a low transmittance for cross-linking radiation, in particular for UV radiation, in blocking areas and a high transmittance for cross-linking radiation, in particular for UV radiation, on the side of the planar primary structure opposite the secondary structure, congruent with the transmitting areas, a translucently colored wash ink is applied and cross-linked by the action of cross-linking radiation, which imparts a color effect to the primary structure in the transmitting areas, and that a reflection-enhancing coating is applied which covers the secondary structure and,If the passbands are formed by recesses in the secondary structure, the primary structure is also coated in the passbands.

[0041] In an advantageous process, a crosslinkable wash ink is applied to the side of the substrate opposite the secondary structure and thus also to the side of the primary structure opposite the secondary structure prior to the application of the reflection-enhancing coating. The wash ink is exposed to crosslinking radiation, particularly UV radiation, through the secondary structure, which acts as an exposure mask, so that the crosslinkable wash ink is crosslinked in areas congruent with the transmission areas and remains uncrosslinked in areas congruent with the blocking areas.

[0042] The wash-on color exposed to crosslinking radiation is subsequently washed, thereby removing it from the uncrosslinked areas while remaining intact in the crosslinked areas. In the uncrosslinked areas, the wash-on color is preferably completely removed, but at least removed to such an extent—for example, by reducing its layer thickness so significantly—that it no longer imparts any color effect.

[0043] Further embodiments and advantages of the invention are explained below with reference to the figures, in which a true-to-scale and true-to-proportion reproduction has been omitted in order to increase clarity.

[0044] They show: Fig. 1 a schematic representation of a banknote with an optically variable security element according to the invention, Fig. 2 schematically a section of the security element of the Fig. 1in cross-section, and Fig. 3 in (a) to (h) intermediate steps in the manufacture of the security element of the Fig. 2 .

[0045] The invention will now be explained using the example of security elements for banknotes. Figure 1 shows a schematic representation of a banknote 10 with an optically variable security element 12 according to the invention in the form of an adhesive-applied transfer element. However, it is understood that the invention is not limited to transfer elements and banknotes, but can be used for all types of security elements, for example, labels on goods and packaging or for securing documents, ID cards, passports, credit cards, health cards, and the like. For banknotes and similar documents, in addition to transfer elements (such as patches with or without their own carrier layer), security threads or security strips, for example, are also possible.

[0046] The security element 12 applied to the banknote 10 is itself very flat, but nevertheless gives the observer the three-dimensional impression of a motif 14 that appears to bulge out from the plane of the banknote 10 and appears in a first color. In practice, the motif 14 can, for example, represent a value number, a portrait, or another graphic motif. Within the motif 14, a movement effect in a second color is visible in a partial area 16. For example, when the banknote 10 is tilted, a light-colored bar can move back and forth along the curved partial area 16, creating a so-called rolling bar effect. The areas of different colors (first or second color) and different effects (three-dimensional motif or moving bar) are precisely registered to one another. This registration is also referred to below as color-to-effect registration.

[0047] The special structure and the inventive manufacture of the security element 12 will now be described with reference to the Figures 2 and 3 explained in more detail, whereby Fig. 2 schematically a section of the security element 12 applied to the banknote 10 in cross section and Fig. 3 show various intermediate steps in the production of the security element 12.

[0048] The security element 12 contains a flat, transparent, colorless carrier 18, for example, a transparent, colorless PET film. The surface area of ​​the carrier 18 defines an xy plane and a z axis perpendicular to it. A reflective surface area 20 consisting of several sublayers is formed on the two opposite sides of the carrier 18. The reflective surface area comprises, on one side of the carrier 18, an embossed structure area with two micromirror embossments 24, 34 at two different heights and, on the opposite side of the carrier 18, a colored wash-ink area 28.

[0049] A first embossed region 24, which in the exemplary embodiment forms the primary structure of the reflective surface region, is provided by micromirror embossings which are embossed into a first transparent embossing lacquer layer 22 applied to the carrier 18 and whose base surfaces lie at a first height above the carrier 18 in the z-direction.

[0050] The first embossing lacquer layer 22 is covered in partial areas 66 by a secondary structure in the form of a second embossing lacquer layer 32 with a second, different relief structure 34 with micromirror embossings.

[0051] The second embossing lacquer layer 32 is visually colored with a translucent color, for example, a red translucent color, and is also mixed with a UV absorber, making it impermeable to UV radiation. The partial regions 66 in which the second embossing lacquer layer 32 is present therefore form UV radiation blocking regions, while the regions 64 without the covering second embossing lacquer layer 32 form transmission regions of high UV transmittance.

[0052] The base areas of the micromirrors of the second embossed region 34 are located at a second, greater height above the carrier 18. Since the security element is designed to be viewed from the side of the carrier opposite the embossed lacquer layers 22, 32 (viewer 50), the relief structure of the first embossed lacquer layer 22 forms a higher-lying relief structure of the security element and the relief structure of the second embossed lacquer layer 32 forms a lower-lying relief structure.

[0053] The micromirror embossments or micromirror arrangements 24, 34 each contain a plurality of micromirrors inclined relative to the xy plane, the local angles of which are selected precisely so that the relief structures of the micromirror embossments 24, 34, in interaction with the color effect of the reflection-enhancing coating 40 described below, the color effect of the second embossing lacquer layer 32, and the color effect of the wash-colored areas, create a desired optical appearance. Specifically, the angles of inclination of the micromirrors in the exemplary embodiment are selected such that the micromirror arrangements 24, 34 create the curved, three-dimensional impression of the motif 14 and the rolling bar effect of the partial area 16.

[0054] In the exemplary embodiment, the micromirrors of the micromirror embossments 24, 34 have a lateral dimension of 10 x 10 µm and a maximum height of 3.5 µm. The height offset relative to the base areas can be, for example, 6 µm.

[0055] The two micromirror arrangements 24, 34 are provided with a common reflection-enhancing coating, for example an opaque metallization 40, which follows the relief profile of the embossing lacquer layer 22 or 32, respectively, and which lies in the blocking regions 66 on the second embossing lacquer layer 32 and in the transmission regions 64 on the first embossing lacquer layer 22.

[0056] On the side of the carrier 18 opposite the micromirror arrangement 24, 34, a cross-linked, translucent wash ink 28 is arranged congruently with the transmission regions 64 of the second embossing lacquer layer 32, which wash ink is designed, for example, to be translucent green.

[0057] The different appearances of the security element 12 for a viewer 50 result from the interaction of the green translucent wash color 28 with the relief structure of the first embossing lacquer layer 22 and its opaque metallization 40 on the one hand, and the color effect of the red translucent embossing lacquer layer 32 with its relief structure and opaque metallization 40 on the other hand.

[0058] Specifically, in the example of Fig. 2 the two micromirror arrangements 24, 34 are arranged in the surface area of ​​the security element 12 in each case directly adjacent to one another, wherein the blocking area 66 is formed, for example, by a 5 mm wide and 2 cm long curved strip within a 2.5 x 2.5 cm 2< large surface area and the transmission area 64 is formed by the surface area of ​​the security element surrounding the strip 66.

[0059] In the transmission area 64, the viewer 50 looks through a transparent protective lacquer layer 38, the green translucent wash color 28 and the transparent embossed lacquer layer 22 onto the higher-lying micromirror arrangement 24, which has a metallic mirror coating on its back, so that the security element 12 appears there with a green, shiny color impression and the optically variable effect of the higher-lying micromirror embossing 24.

[0060] In the blocking area 66, however, the viewer 50 looks through the transparent protective lacquer layer 38, through the gaps in the wash-ink layer, through the transparent embossing lacquer layer 22 and the red translucent embossing lacquer layer 32, onto the deeper micromirror arrangement 34, which is also metallically mirrored on the back. The refractive index of the second embossing lacquer layer 32 differs little or not at all from the refractive index of the first embossing lacquer layer 22, so that the embossing present in the blocking area 66 at the interface between the two embossing lacquer layers 22, 32 is not visually visible. Rather, it is practically erased by overprinting with the second embossing lacquer layer. The security element 12 therefore appears in the blocking area 66 with a shiny red color impression and the optically variable effect of the deeper micromirror embossing 34.

[0061] Since the height difference between the two micromirror arrangements 24, 34 is in the range of a few micrometers, it is not perceptible to the observer, so that the two differently colored motifs and the different effects appear to be arranged next to each other in exact registration.

[0062] The inventive production of the security element 12 will now be described with reference to Figure 3 described in more detail, with (a) to (h) each showing intermediate steps in the manufacture of the security element.

[0063] First, with reference to Fig. 3(a)A transparent carrier 18, for example, a transparent, colorless PET film, is provided and provided with a primary structure in the form of a first, transparent, and colorless embossing lacquer layer 22. Using an embossing tool (not shown), the micromirror embossing 24, which creates the desired motif 14 of the security element 12, is embossed into the first embossing lacquer layer 22. With the preferred use of a UV embossing lacquer, the embossing lacquer layer 22 is subsequently cured.

[0064] A secondary structure in the form of a second embossing lacquer layer 32 is printed onto the first embossing lacquer layer 22 using a printing cylinder (not shown) in the desired blocking area 66 of the moving beam, as shown in Fig. 3(b)The second embossing lacquer layer 32 is colored, for example, in a translucent red and is also provided with a UV absorber. The refractive index of the second embossing lacquer layer 32 differs little or not at all from the refractive index of the first embossing lacquer layer 22, so that the information of the first micromirror embossing 24 present in the blocking region 66 is erased and no longer visually visible.

[0065] With reference to Fig. 3(c) The second embossing lacquer layer 32 is then provided with the micromirror embossing 34 that creates the rolling bar effect using an embossing tool (not shown). If a UV embossing lacquer is used, the embossing lacquer layer 32 is subsequently cured.

[0066] Subsequently, a full-surface layer of a cross-linkable, translucent wash ink 26 is applied to the side of the carrier 18 opposite the embossing lacquer layers 22, 32, as shown in Fig. 3(d) shown.

[0067] An advantageous wash color 26 contains as an essential component a water-soluble binder which is solid at room temperature and which can be crosslinked in conjunction with the other components and which is mixed with a soluble dye or a finely dispersed pigment for coloring.

[0068] The resulting layer sequence is then exposed to UV radiation 60 from the side of the embossing lacquer layers 22, 32, as shown in Fig. 3(e) shown. In the transmission areas 64, the UV radiation leads to the crosslinking of the wash ink 26, which thereby becomes insoluble and no longer washable in these areas 28 (indicated in the figures by close cross-hatching). In contrast, the UV radiation 60 in the blocking areas 66 is blocked by the UV absorber contained in the embossing lacquer layer 32, so that the wash ink 26 remains water-soluble in the areas congruent with the blocking areas 66.

[0069] Subsequently, the UV-exposed layer sequence is washed, and the wash ink that is congruent with the blocking areas 66 is thereby removed. The blocking areas 66 are then free of wash ink. However, the crosslinked, insoluble wash ink areas 28 remain on the carrier 18, which are congruent with the transmission areas 64 of the second embossing lacquer layer 32, as shown in Fig. 3(f) shown.

[0070] With reference to Fig. 3(g)The two embossing lacquer layers 22, 32 are then provided over their entire surface with a common reflection-enhancing coating 40, in particular a metallization or a high-index coating. The difference in refractive index between the reflection-enhancing coating 40 and the embossing lacquer layers 22 and 32, respectively, ensures that the micromirror embossing 24, 34 is clearly visible when viewing the security element from the side of the embossing lacquer layers. In the illustrated embodiment, the reflection-enhancing coating 40 is formed by an aluminum layer.

[0071] Finally, the coated micromirror arrays 24, 34 and the structured wax color areas 28 are each leveled with a transparent lacquer layer 38, as in Fig. 3(h)shown, and if necessary, further functional or protective layers required for the use of the security element are applied to complete the security element.

[0072] The security element of the Fig. 3(h) For example, a banknote can be stuck onto the banknote paper using an adhesive layer, as in Fig. 2 shown. List of reference symbols

[0073] 10 Banknote 12 Security element 14 Motif 16 Partial area with rolling bar effect 18 Carrier 20 Reflective surface area 22 First embossing lacquer layer 24 First embossing structure 26 Cross-linkable, translucent wash ink 28 Cross-linked wash ink 32 Second embossing lacquer layer 34 Second embossing structure 38 Transparent lacquer layer 40 Reflection-enhancing coating 50 Viewer 60 UV radiation 64 Transmitting areas 66 Blocking areas

Claims

1. Optically variable security element (12) for safeguarding valuable objects, the surface area of which security element defines a z-axis perpendicular thereto, comprising a reflective surface region (20), wherein - the reflective surface region (20) contains a planar, transmissive primary structure (22) formed by a printing or embossing structure, - the planar primary structure (22) is covered by a secondary structure (32) in the form of an embossing lacquer layer, which contains an impressed relief structure (34) and which has in blocking regions (66) a low transmissivity and in transmissive regions (64) a high transmissivity for a crosslinking radiation, - a reflection-enhancing coating (40) is provided, which coats the secondary structure (32) and, inasmuch as the transmissive regions (64) are formed by cutouts of the secondary structure (32), in the transmissive regions (64) also coats the primary structure (22), and in that - on the opposite side of the planar primary structure (22) relative to the secondary structure (32), congruently with the transmissive regions (64), there is arranged a crosslinked, translucently coloured washable ink (28), which imparts a colour effect to the primary structure (22) in the transmissive regions (64).

2. Security element according to Claim 1, wherein the transmissive regions (64) of the secondary structure (32) are formed by cutouts of the secondary structure; or the transmissive regions (64) and the blocking regions (66) of the secondary structure (32) are formed by material regions of the secondary structure which differ in their transmissivity for the crosslinking radiation.

3. Security element according to at least one of Claims 1 to 2, wherein the secondary structure (32) has the high transmissivity for UV radiation as crosslinking radiation in the transmissive regions (64); and / or an absorber for the crosslinking radiation, in particular a UV absorber, is provided in the blocking regions (66) of the secondary structure (32); and / or the reflection-enhancing coating (40) follows the relief course of the relief structure (34) of the secondary structure embossing lacquer layer (32) in the blocking regions (66).

4. Security element according to at least one of Claims 1 to 3, wherein the primary structure (22) is embodied in the form of a further embossing lacquer layer provided with an impressed relief structure (24) embodied differently from the relief structure (34) of the secondary structure embossing lacquer layer (32), wherein preferably the reflection-enhancing coating (40) follows the relief course of the further relief structure (24) of the primary structure (22) in transmissive regions (64) of the secondary structure (32) that are formed by cutouts.

5. Security element according to at least one of Claims 1 to 4, wherein the secondary structure embossing lacquer layer (32) is translucently coloured, preferably with a colour effect that differs from the colour effect of the translucently coloured washable ink (28).

6. Security element according to at least one of Claims 1 to 5, wherein the washable ink is water-soluble in an uncrosslinked state (26) and water-insoluble in a crosslinked state (28).

7. Security element according to at least one of Claims 1 to 6, wherein the reflection-enhancing coating (40) is formed by a metallization, a high refractive index coating, a thin-film element with a colour shift effect or a cholesteric liquid crystal layer.

8. Security element according to at least one of Claims 1 to 7, wherein the relief structure (34) of the secondary structure (32) and / or the optionally present relief structure (24) of the primary structure (22) are / is formed by micromirror arrangements with directionally reflective micromirrors, in particular with mirrors having a non-diffractive effect, and preferably with plane mirrors, concave mirrors and / or Fresnel-like mirrors.

9. Security element according to at least one of Claims 1 to 8, wherein the blocking regions (66) and the transmissive regions (64) at least in a partial region of the surface region are embodied as a regular or irregular grid with grid elements and grid interspaces, wherein the dimensions of the grid elements and grid interspaces are less than 140 µm, preferably between 20 µm and 100 µm, in particular between 20 µm and 60 µm, in one or both lateral directions.

10. Security element according to at least one of Claims 1 to 9, wherein the blocking regions (66) and the transmissive regions (64) at least in a partial region of the surface region form an effect region in which the blocking regions and / or the transmissive regions have lateral dimensions of more than 140 µm.

11. Security element according to at least one of Claims 1 to 10, wherein in the security element (12) negative identifiers are formed by cutouts in the reflection-enhancing coating (40).

12. Data carrier (10) comprising an optically variable security element (12) according to at least one of Claims 1 to 11.

13. Method for producing an optically variable security element (12), wherein - a carrier (18) is provided, the surface area of which defines a z-axis perpendicular thereto, - in a surface region (20) the carrier (18) is provided with a planar, transmissive primary structure (22) formed by a printing or embossing structure, - the planar primary structure (22) is covered by a secondary structure (32) in the form of an embossing lacquer layer, which contains an impressed relief structure (34) and which has in blocking regions (66) a low transmissivity and in transmissive regions (64) a high transmissivity for a crosslinking radiation, - on the opposite side of the planar primary structure (22) relative to the secondary structure (32), congruently with the transmissive regions (64), a translucently coloured washable ink is applied and crosslinked by the action of crosslinking radiation, which imparts a colour effect to the primary structure (22) in the transmissive regions (64), and in that - a reflection-enhancing coating (40) is applied, which coats the secondary structure (32) and, inasmuch as the transmissive regions (64) are formed by cutouts of the secondary structure (32), in the transmissive regions (64) also coats the primary structure (22).

14. Method according to Claim 13, wherein prior to applying the reflection-enhancing coating (40) - the crosslinkable washable ink (26) is applied on the opposite side of the carrier (18) relative to the secondary structure (32), - crosslinking radiation, in particular UV radiation, impinges on the washable ink (26) through the secondary structure (32) acting as an exposure mask, such that the crosslinkable washable ink (26) is crosslinked in surface regions congruent with the transmissive regions (64) and remains uncrosslinked in surface regions congruent with the blocking regions (66).

15. Method according to Claim 13 or 14, wherein the washable ink (26, 28) impinged on by crosslinking radiation through the secondary structure (32) is washed, and as a result is removed in the uncrosslinked surface regions and is retained in the crosslinked surface regions.