WO2009033601A1 - Visually variable security element - Google Patents

Abstract

The invention relates to a visually variable security element (12) for safeguarding valuables with an at least partially translucent, visually variable color layer (26) which displays a motif (28, 30) in the form of patterns, signs or coding and in which the color layer (26) contains first visually variable decorative pigments (32) and second magnetically orientable decorative pigments (34, 36) which are magnetically oriented in the shape of the motif to be represented (28, 30).

Description

 Optically variable security element

The invention relates to an optically variable security element for securing valuables. The invention further relates to a method and an apparatus for producing such a security element as well as a security paper and a data carrier with such a security element.

Data carriers, such as valuables or identity documents, but also other valuables, such as branded goods, are often provided with security elements for the purpose of security, which permit verification of the authenticity of the data carrier and at the same time serve as protection against unauthorized reproduction. The security elements can be embodied, for example, in the form of a security thread embedded in a banknote, a covering film for a banknote with a hole, an applied security strip, a self-supporting transfer element or else in the form of a feature area printed directly on a value document.

A special role in the authenticity assurance play security elements, the viewing angle-dependent visual effects show, as they can not be reproduced even with the latest copiers. For this purpose, the security elements are equipped with optically variable elements which give the viewer a different image impression under different viewing angles and, for example, show a different color or brightness impression and / or another graphic motif depending on the viewing angle.

In this context, it is known to use security elements with multi-layered thin-film elements whose color impression changes with the viewing angle for the viewer, and when tilting the screen.

BESTÄTIGUNGSKOP1E For example, it changes from green to blue, from blue to magenta, or from magenta to green. The occurrence of such color changes when tilting a security element is referred to below as a color shift effect.

From document WO 02/073250 A2, optically variable thin-film elements are known in whose layer structure at least one magnetic layer is integrated. The magnetic properties of these optically variable thin-film elements can then be used as an additional authenticity mark.

The document EP 1 780 040 A2 describes a security element in which magnetically oriented pigment particles are present in a partial region which produce a kinematic visual effect. The magnetically oriented pigment particles may in particular also have optically variable properties.

Proceeding from this, the object of the invention is to further improve a security element of the aforementioned type and, in particular, to provide a security element with an attractive visual appearance and high security against counterfeiting, which moreover allows an intelligent combination with further, in particular underlying, security features.

This object is achieved by the security element having the features of the main claim. A method and an apparatus for producing such a security element, a security paper and a data carrier with such a security element are in the sibling Claims specified. Further developments of the invention are the subject of the dependent claims.

According to the invention, a generic security element has an at least partially translucent, optically variable color layer which shows a motif in the form of patterns, characters or a coding, and in which the color layer of the security element contains first, optically variable effect pigments and second, magnetically alignable effect pigments , which are magnetically aligned in the shape of the motif to be displayed.

Such a security element offers a combination of attractive visual effects, namely, on the one hand, the optically variable effect of the first effect pigments and, on the other hand, the motif produced by the magnetic alignment of the second effect pigments, which has a pronounced three-dimensional appearance. Due to their at least partially present translucency, the optically variable ink layer can also be combined with other underlying security features, such as an information-carrying print layer or a see-through area.

In the context of the present description, "translucent" means translucent in the sense of a certain or complete translucency and thus also includes transparency. A translucent layer makes it possible to perceive the objects behind or below it, even if the brightness of the objects can be reduced by the translucent layer and / or the color of the objects can be changed. On the other hand, if the light transmission of a layer is so low that the objects behind or underneath are no longer recognizable, it is no longer translucent but is called opaque or opaque. The invention is based on the idea to use a color layer with two different effect pigments with different specific properties. The first effect pigments are optically variable, while the second effect pigments are magnetically alignable. Essentially only the latter, but not the first effect pigments are magnetically oriented in the orientation of an external magnetic field in the form of the motif to be displayed.

This decoupling of the optically variable and the magnetic intrinsic properties allows cost-effective production, since effect pigments which combine optically variable and magnetic properties require a higher manufacturing outlay and thus also a higher cost. In addition, such effect pigments are typically opaque, so that an intelligent combination with other printing processes or printing inks is possible only to a very limited extent. In addition, the required layer structure of the pigments and the associated selective reflection makes stringent demands on the possible layer thicknesses of the magnetic material. This leads to limitations in the magnetic properties, in particular the remanence and the coercive field strength, which make it difficult to produce machine-readable security elements.

In a preferred embodiment of the invention, the optically variable ink layer contains a pigment mixture with the first and second effect pigments. Alternatively, the optically variable color layer may also contain a pure magnetic layer with the second effect pigments and a pure color layer with the first effect pigments arranged above the pure magnetic layer. The first effect pigments are advantageously pigments prepared on the basis of liquid-crystalline polymers or so-called pearlescent pigments, such as the silver white, gold luster or metallic luster pigments marketed by Merck KGaA under the name Iriodin® or Colorcrypt. Both pigments based on liquid-crystalline material and pearlescent pigments are translucent on their own. In other likewise advantageous embodiments of the invention, the first effect pigments are formed by interference layer pigments. Such interference layer pigments typically have a thin-film structure which expediently contains at least one reflection layer, one absorber layer and a dielectric spacer layer arranged between the reflection layer and the absorber layer. Interfacial layer pigments can be translucent per se, although opaque interference layer pigments are also known.

The second effect pigments are preferably formed on the basis of high-purity iron powder and can be prepared, for example, from reducing-treated carbonyl iron powder. Advantageous platelet-shaped iron pigments can be taken in particular from the document EP 1 251 152 Bl, whose disclosure on the preparation and properties of such pigments is included in the present description.

In an advantageous embodiment of the invention, the second effect pigments are hard magnetic and thus allow in a particularly reliable manner a machine magnetic readout of the motif shown. Preferably, the second effect pigments are in the form of a machine-readable magnetic coding, such as a bar code, aligned. Of course, the second effect pigments may in principle also be soft magnetic, although soft magnetic effect pigments are suitable for the magenta Mechanical magnetic readings are not as well suited as hard magnetic pigments.

The second effect pigments are preferably non-spherical, for example of a needle-shaped design. Particular preference is given to effect pigments which have a platelet form. Hereinafter, the largest diameter of a non-spherical pigment is referred to as the length or size of the pigment, while the thickness of the pigment is referred to as the pigment thickness. In general, the thickness of the pigments with the smallest diameter of the pigment will be identical. Furthermore, the terms length, size and largest diameter of the pigment as well as thickness and smallest diameter of the pigment are used synonymously. The ratio of the largest to the smallest diameter, ie the diameter-to-thickness ratio of the non-spherical second effect pigments is preferably more than 5: 1, preferably more than 10: 1. This ratio is particularly preferably between 40: 1 and 400: 1. The largest diameter, ie the length of the non-spherical second effect pigments is advantageously more than 2 μm, preferably more than 5 μm, more preferably more than 10 μm and very particularly preferably about 13 μm to about 15 μm.

The use of magnetically alignable effect pigments in the micrometer range and in particular in the stated size range on the one hand has the advantage that the particle concentration can be kept lower compared to nanoparticles. In addition, due to the more favorable diameter-to-thickness ratio without external forces, these pigments align better parallel to the layer surface.

Platelet-shaped effect pigments, in particular in the preferred size range and in the preferred diameter-to-thickness range, can be obtained by an external magnetic field relative to the layer plane can be oriented as desired. Depending on their orientation, they then either leave the view of the underlying layers largely free (approximately perpendicular orientation relative to the layer plane) or block them partially (oblique orientation relative to the layer plane) or completely (essentially horizontal orientation relative) to the layer plane). With high diameter-to-thickness ratios, high contrasts between translucent and opaque layer areas can be set.

According to a preferred embodiment of the invention, the second effect pigments are platelet-shaped and are aligned in first partial areas essentially perpendicular to the plane of the color layer in order to form translucent subregions of the color layer. Alternatively or additionally, platelet-shaped second effect pigments may be aligned in second partial areas substantially parallel to the plane of the color layer in order to form opaque partial areas of the color layer.

The optically variable ink layer is preferably formed by a screen printing layer, in some embodiments also by a gravure printing layer. It may additionally be blind-embossed in all of the aforementioned embodiments, in particular for enhancing the 3D effect of the magnetically oriented effect pigments.

To fix the magnetically oriented motif, the color layer with the pigment mixture is preferably formed on the basis of a UV-curing color system, pure UV systems, UV / water-based systems or even UV / solvent-based systems being considered. In addition to the first and second effect pigments, the color layer may also comprise further pigments, in particular isotropic pigments and / or soft magnetic pigments. hold. Of course, the further pigments or, more generally, further additives may have all visually and / or machine-detectable properties which do not or only slightly impair the visual impression of the security element according to the invention.

In an advantageous embodiment, the optically variable ink layer is applied to a banknote paper or on a colored background layer. The substrate material for the banknote paper is any type of paper, in particular cotton vellum paper. Of course, it is also possible to use paper which contains a proportion of polymeric material in the range of 0 <x <100% by weight.

Furthermore, it is conceivable in principle, although not currently preferred, for the substrate material of the banknote or, more generally, of a data carrier to be a plastic film, for example a plastic film. B. a polyester film is. The film may also be monoaxially or biaxially stretched. The stretching of the film, inter alia, leads to it receiving polarizing properties that can be used as another security feature.

It may also be expedient if the substrate material of the banknote paper is a multilayer composite which has at least one layer of paper or a paper-like material. Such a composite is characterized by an extremely high stability, which is for the durability of the paper or disk of great advantage.

It is also conceivable, however, to use a multilayer, paper-free composite material as the substrate material. These materials are also not preferred at present, but can be used with advantage in certain climatic regions of the earth. All materials used as substrate material may have additives which serve as authenticity features. It is primarily to think of luminescent, which are preferably transparent in the visible wavelength range and in the non-visible wavelength range by a suitable tool, for. B. a UV or IR radiation emitting radiation source can be excited to produce a visible or at least detectable with auxiliary luminescence. Other security features can also be used to advantage if they do not impair the contemplation of the security element according to the invention or at least do not significantly affect it.

Background layers with dark colors usually lead to a particularly high brilliance of the optically variable effects. However, a transparent or translucent film is also suitable as a substrate. In this case, the security element may advantageously be used in or above a window area or a through opening of a value document as a see-through security element. The film may be formed as a patch covering a partial surface of the substrate or as a strip extending substantially the entire length or width of the security paper or document of value. The materials used for the film are primarily the plastics PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PEN (polyethylene naphthalate), PP (polypropylene), PA (polyamide), PE (polyethylene). The film may also be monoaxially or biaxially stretched.

In some embodiments, the opening is already created in the manufacture of the security paper used for the bill and has a fibrous, irregular edge. Such an edge is characteristic of apertures already made during sheet formation and can not be generated later. Details of the production of the fibrous, irregular edge can be found in WO 03/054297 A2. In that regard, the disclosure of WO 03/054297 A2 is included in the present application. In other embodiments, the opening is produced only after papermaking by punching or cutting, for example by laser beam cutting.

In one development of the invention, the optically variable ink layer can be applied to an information-carrying background layer, in particular a screen-printing layer or a gravure printing layer. Since the information is recognizable in the translucent areas of the color layer, but hidden in the opaque areas, the color layer and background layer can cooperate to produce a further authenticity feature, as explained in more detail below.

The background layer can advantageously also have thermochromic properties in order to create an interactively influenceable security element. Such a thermochromic background layer can in particular be designed so that when it is activated by increasing the temperature, the optically variable effect of the first effect pigments for the viewer disappears.

The invention also includes a method for producing an optically variable security element for securing valuables, in which

a translucent, at least partially translucent, optically variable ink layer is applied to a substrate containing the first, optically variable effect pigments and second, magnetically alignable effect pigments, and the second effect pigments are aligned by an external magnetic field to form a motif in the form of patterns, characters or a code.

In this case, the first and second effect pigments are preferably mixed to form a pigment mixture and jointly printed, preferably by screen printing or intaglio printing.

Alternatively, a pure magnetic layer with the second effect pigments can first be printed onto the substrate, and then a pure color layer with the first effect pigments can be printed over the pure magnetic layer. Also, the pure magnetic layer and / or the pure ink layer is preferably printed by screen printing or intaglio printing.

The motive generated by the magnetic alignment is permanently fixed in an advantageous embodiment by UV curing of the ink layer or the pure magnetic layer.

The invention further comprises a security paper for the production of value documents or the like and a data carrier, in particular a value document, such as a banknote, a passport, a document, an identity card, credit card or the like. The security paper or the data carrier are equipped according to the invention with a security element of the type described. The security element can, in particular if it is present on a transparent or translucent substrate, also be arranged in or above a window area or a through opening of the security paper or the data carrier. The invention further provides an apparatus for carrying out the described production method, which comprises means for applying the optically variable ink layer to a substrate and means for magnetically aligning the second effect pigments, wherein the means for magnetic alignment is preferably formed by an arrangement of permanent magnets or electromagnets are.

In this case, the optically variable ink layer is advantageously applied to the intended substrate by a suitable method, and the second effect pigments are then aligned, for. B. by a magnetic pressure cylinder. Subsequently, the optically variable ink layer is permanently fixed together with the motif formed by the orientation of the second effect pigments, which z. B. can be done by the above-mentioned UV curing.

In an expedient embodiment, the means for magnetic

Aligning formed by a magnetic sieve, so that the second effect pigments are already magnetically aligned in screen printing when printing the ink layer or the pure magnetic layer.

If the second effect pigments or the color layer are applied by intaglio printing, the means for magnetic alignment can also be formed by a magnetic throat plate, so that the second effect pigments are already magnetically alignable in the intaglio printing when printing the ink layer or the pure magnetic layer.

Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation in terms of scale and proportions has been dispensed with in order to increase the clarity. Show it:

1 is a schematic representation of a banknote with a security element according to the invention,

FIG. 2 shows the banknote of FIG. 1 in the area of the security element in FIG

Cross-section,

3 shows an interactively influenceable security element according to another embodiment of the invention in cross-section,

4 shows a security element according to a further exemplary embodiment of the invention in cross section,

FIG. 5 shows a banknote with a see-through security element according to the invention, which is arranged over a continuous opening, and FIG

6 shows a security element according to a further exemplary embodiment of the invention with an alternative design of the optically variable ink layer.

The invention will now be explained using the example of a banknote. 1 shows a schematic representation of a banknote 10 which is provided with a security element 12 according to the invention shown in cross-section in FIG.

With reference to the illustration of FIG. 2, a printing layer 22 is applied to the banknote paper 20 in the region of the security element 12, which any information, such as a line pattern 24, an alphanumeric string, a logo or the like may represent. The printing layer 22 can be applied to the banknote paper 20, for example, by screen printing or intaglio printing, with the application of the printing layer 22 particularly preferably taking place together with further printed layers, not illustrated in the figures, which form the so-called background printing of the data medium. The further printing layers can be formed, for example, as guilloches or similar patterns and, like the printing layer 22, can be applied to the data carrier in flexographic printing.

About the information-carrying print layer 22 is an optically variable ink layer 26 is printed with a color shift effect in the screen printing process, in which the color impression of the layer 26 for the viewer when tilting the security element 12 z. B. changes from green when viewed perpendicularly to blue when viewed obliquely. It is also conceivable a color change of z. B. coppery green or from gold to green.

Furthermore, the color layer 26 contains a motif which, in the exemplary embodiment of FIG. 2, is designed for illustration in the form of a simple stripe pattern 28, 30. As explained in more detail below, this motif 28, 30 has a pronounced 3D effect for the viewer due to its formation due to the different orientation of platelet-shaped pigments 34, 36.

In the region of the strips 30, the ink layer 26 is translucent, so that in the partial regions 30 the information 24 can be seen through the ink layer 26. On the other hand, in the area of the strips 28, the ink layer 26 is opaque, where the information 24 of the printing layer 22 is hidden. In order to produce this combination of a motif with 3D effect, color shift effect and partial visibility of the background printing layer 22, the color layer 26 is printed using a pigment mixture of first effect pigments 32 and second effect pigments 34, 36.

The first effect pigments 32 is optically variable pigments, for example, on the basis of liquid-crystalline polymers produced iridescent pigments or pearlescent pigments, as are marketed, for example from Merck KGaA under the designation Iriodin ^® or Colorcrypt ^®. Also interference layer pigments with a multi-layer thin-film structure of z. For example, a reflection layer, an absorber layer, and a dielectric spacer layer disposed between reflection layer and absorber layer may be considered as first effect pigments 32, although these interference layer pigments are not as well suited as liquid crystal pigments or pearlescent pigments due to their lower light transmission.

In addition to these optically variable first effect pigments 32, the pigment mixture comprises, as second effect pigments, magnetically alignable, platelet-shaped iron pigments 34, 36 which in the exemplary embodiment are produced from reducing-treated carbonyl iron powder. Such platelet-shaped iron pigments can be produced with a high ratio of platelet diameter to platelet thickness, wherein the (largest) platelet diameter is preferably between 6 .mu.m and 60 .mu.m and the platelet thickness in particular between 40 nm and 250 nm. Details of the preparation and properties of such platelet-shaped iron pigments can be found in the document EP 1 251 152 Bl, the disclosure of which is incorporated into the present description. For the production of the color layer 26, the first and second effect pigments 32, 34, 36 were mixed and jointly printed by screen printing. Then, the magnetically alignable second effect pigments were partially aligned by an external magnetic field. The iron pigments 34, 36 are oriented here with the platelet expansion along the magnetic field lines, so that the iron pigments 36 are aligned substantially perpendicular to the plane of the color layer in those regions 30 in which the magnetic field lines are substantially perpendicular to the substrate plane during the alignment step be as shown in Fig. 2. In those regions 28 in which the magnetic field lines run essentially parallel to the substrate plane, the orientation of the iron pigments 34, which lies substantially in the plane of the ink layer, accordingly results.

The platelet-shaped iron pigments 34, 36 are aligned according to the invention in the form of a desired motif, in the embodiment in the form of the stripe motif 28, 30. For the human eye, the motifs created in this way appear with an effective, three-dimensional appearance, which in the context of this description is also referred to as a 3D effect or 3D impression of the motif.

For the sake of simplicity, only two orientations, namely perpendicular (90 °, pigments 36) or parallel (0 °, pigments 34) to the substrate plane are shown in the exemplary embodiment of FIG. 2. It is understood, however, that any angle α between the iron pigment platelets and the layer plane can be adjusted by appropriate orientation of the magnetic field lines. In particular, it is also possible to generate continuous, spatially slowly varying transitions in the orientation of the iron pigments. The non-magnetic first effect pigments 32 are not or hardly influenced by the external magnetic field during the alignment step, their orientation is therefore the same in the subregions 28 and 30.

After the magnetic alignment of the second effect pigments 34, 36, the color layer 26 is dried. In order to be able to fix the magnetically generated motif permanently, in particular UV-curing color systems are used, pure UV systems, UV / water-based systems or even UV / solvent-based systems being considered.

As can also be seen in FIG. 2, the aligned effect pigments 34, 36, due to their platelike shape, act like the slats of a venetian blind, which can clear the view of the underlying layers or completely or partially block them. In regions 28 in which the iron pigments 34 are oriented substantially parallel to the substrate plane, they limit the view of the underlying printing layer 22 so strongly that the ink layer 26 appears opaque in this region. It should be remembered that in practice the opacifying effect of the pigments 34 is of course brought about by a multiplicity of pigments, which exceeds the few pigments 34 in the schematic representation of FIG. 2 by a multiple. In contrast, the iron pigments 36 release the view of the print layer 22 in the regions 30 in which they are aligned essentially perpendicular to the substrate plane.

Due to the relatively high ratio of platelet diameter to platelet thickness, a high contrast can be generated between covering partial regions 28 and translucent partial regions 30. It is understood that by a continuous transition of platelet orientation also a soft, continuous transition between translucent and opaque areas of the ink layer 26 can be generated.

The color shift effect of the first effect pigments 32, which are not substantially influenced by the external magnetic field, remains visible in both partial areas 28, 30. Due to the superposition with the metallic luster of the second effect pigments oriented parallel to the substrate surface 34, however, it is generally markedly weaker in the partial region 28 than in the partial region 30. The brilliance of the color shift effect in the partial region 30 also depends on the design of the undercoat layer when using dark colors a particularly high brilliance is achieved.

The embodiment of FIG. 3 shows a security element 40 which allows an interactive influence on the visual appearance. For this purpose, a substrate 42 is provided with an imprint 43, in particular an ink jet, in the form of patterns and / or marks 45. On the imprint 43, a thermochromic background layer 44 is applied, for example by screen printing or intaglio printing. On this thermochromic layer 44 is then an optically variable ink layer 26 with motif, as described in connection with FIG. 2, printed and magnetically aligned.

The thermochromic layer 44 is designed such that the color shift effect of the color layer 26 disappears upon activation of the thermochromic layer 44 for the viewer and only the coarse structure of the aligned magnetic pigments 34, 36 is visible. For example, if the thermochromic layer 44 changes color from black (or generally a dark appearance) to white (or generally a bright appearance) upon activation by temperature elevation, the brilliance of the color-shift effect is significantly reduced upon activation, to a degree . in which the optically variable effect of the first effect pigments 32 completely disappears for the viewer. At the same time, the imprint 43 can be recognized by the very light layer 44 for the viewer. Upon cooling, the color of the thermochromic layer 44 changes back to black or to the original dark appearance, and the color shift effect of the color layer 26 reappears. At the same time, the dark layer 44 then covers the imprint 43 arranged below it again.

In this way, 3D information and / or an optically variable effect can be deleted interactively by increasing the temperature or reduced to two-dimensional information. Furthermore, the thermochromic layer 44 acts as an interactive switch, with which the view of the imprint 43 or the information 45 can be released for the viewer. The described embodiment therefore has a great recognition value for the viewer and generally a very high security against counterfeiting.

The thermochromic layer 44 may further be formed over the entire surface or with information, for. In the form of patterns and / or characters. It can also have a mixture of different thermochromic colors with different activation temperatures, so that a cascade of changing optically variable effects arises when the temperature increases.

As a further embodiment of the invention, FIG. 4 shows a security element 50 in which a background layer 54 with image information is applied to a substrate 52. About the background layer 54, an optically variable ink layer 56 is printed by screen printing with a pigment mixture 58, 60, the first effect pigments 58 on the basis are made of cholesteric liquid crystalline polymers. These translucent optically variable effect pigments 58 appear in a vertical plan view z. Green and tilting blue. Of course, a change of color from copper to green or from gold to green can also be achieved.

The second effect pigments 60 are formed by platelet-shaped iron pigments, which in the exemplary embodiment have a mean platelet diameter of 20 μm to 30 μm and a thickness of a few tens to a few hundred nanometers (nm). If these second effect pigments 60 are aligned by an external point-shaped magnet 66, the result is a rotationally symmetrical orientation pattern, as shown schematically in cross-section in FIG. For clarity, the second effect pigments 60 are shown in FIG. 4 with short dashes and the first effect pigments 58 as circular disks, although the latter may also be non-spherical, for example in the form of needles or platelets. However, since the first effect pigments 58 are virtually unaffected by the external magnetic field, their orientation over the entire area of the printed ink layer 56 is substantially homogeneous.

After fixing the magnetic alignment of the second effect pigments 60, a ring-shaped 3D motif combined with the color-shift effect of the first effect pigments 58 is obtained with soft continuous transitions. In a central region 62 in which the second effect pigments 60 are oriented substantially perpendicular to the substrate plane, the color layer 56 is translucent when viewed perpendicularly and the image information of the background layer 54 is visible to the viewer 64. Outside the central region 62, the second effect pigments 60 are increasingly off the vertical tilted, so that the color layer 56 acts increasingly covering in the manner of a closing blind until the image information for the viewer 64 is no longer recognizable.

As can also be seen in FIG. 4, the oblique view of the security element results in a slightly displaced region 62 ', in which the second effect pigments 60 are oriented vertically for the observer 64' and the color layer 56 thus appears translucent. Accordingly, the viewer 64 'can see a slightly shifted section of the image information of the background layer 54, while the image information outside the area 62' is increasingly obscured.

When tilting the security element 50, a slightly different area of the image information is therefore recognizable, so that the image information seems to "swim away" for the viewer. Of course, this motion effect is combined with the already described 3D effect of the subject and the color shift effect of the first effect pigments 58.

Instead of the simple ring structure described by way of example, as can be generated by means of a point magnet, it is of course also possible to generate much more complex motifs by means of a suitable magnetic alignment.

The optically variable ink layer with the pigment mixture may be printed not only on an opaque or substantially opaque substrate but also on a transparent or translucent film. As shown in FIG. 5, such a film having the optically variable ink layer may be disposed over a window portion or through opening 72 of a bill 70 to form a see-through security element 74. Only the magnetic orientation of the second effect pigments can be seen by looking through it, which is indicated in FIG. 5 by way of example by a ring structure 76. The color-shift effect of the first effect pigments is virtually invisible on account of the light background when viewed through. If the banknote 70 is placed on a dark background, in addition to the 3D effect of the magnetically oriented motif 76, the color-shift effect of the first effect pigments also appears.

Such a dark background may also be provided on the banknote 70 itself. For example, a dark printing area may be arranged on the banknote such that the see-through security element 74 comes to rest on the dark printing area by folding the note. For further authenticity assurance, the printing area may contain additional information, from which only the part lying in the translucent area can be seen after folding the banknote.

6 shows a security element 80 according to the invention with an alternative design of the optically variable ink layer 84. In this exemplary embodiment, a screen printing ink having magnetically alignable iron pigments 86 is first printed on any substrate 82 and the pigments 86 are aligned in accordance with the desired motif. Subsequently, a pure color layer 90 with optically variable effect pigments 92 is printed on this pure magnetic layer 88. Due to the magnetic orientation of the iron pigments 86, the print pattern appears black in some areas, while in non-oriented areas the metallic impression dominates. In particular, when using effect pigments 92, the visual impression of which strongly depends on the background color, the overprint shows interesting optical effects. It is understood that the magnetic layer 88 is in principle also arranged above the color layer 90 can be. Due to the opacity of regions with horizontally oriented iron pigments 86, however, the optically variable impression of the effect pigments 92 would then essentially only be recognizable in regions in which iron pigments 86 permit the view of the effect pigments 92 arranged underneath because of their orientation. As a result, in such an embodiment, the observer would perceive a 3D effect (magnetic layer 88), which would be combined in regions with an optically variable effect (color layer 90). At present, however, the embodiment shown in FIG. 6 is preferred in which the ink layer 90 is disposed over the magnetic layer 88.

In all described embodiments, the optically variable ink layer can also be blind embossed in intaglio, in particular for enhancing the 3D optical impression. The platelet-shaped iron pigments preferably used are hard-magnetic, so that their orientation pattern can also be used as a machine-readable authenticity mark.

Furthermore, resulting from the anisotropic geometry of the iron platelets and a partially different orientation anisotropic magnetic properties of the ink layer. In this way, by applying a motif-forming magnetic field in a homogeneously applied ink layer regions with different magnetic properties can be generated, which can also be read by machine. It is understood that the first and second effect pigments can also be combined with further pigments, in particular with isotropic pigments and / or soft magnetic pigments, which in themselves make substantially no modulation of the magnetic properties of the color layer possible. In the screen printing process, the orientation of the magnetically alignable effect pigments can also be achieved by using magnetic sieves. In intaglio printing, the use of magnetic throat plates is considered for this purpose. As already mentioned, the magnetic alignment of the effect pigments is furthermore possible in a particularly simple manner after the application of the optically variable ink layer by means of a suitable magnetic field.

Claims

Patent claims 1. Optically variable security element for securing valuables with an at least partially translucent, optically variable ink layer, which shows a motif in the form of patterns, characters or a coding in which the ink layer first, optically variable effect pigments and second, magnetically alignable effect pigments contains, which are magnetically aligned in the form of the motif to be displayed. 2. Security element according to claim 1, characterized in that the optically variable ink layer contains a pigment mixture with the first and second effect pigments. 3. Security element according to claim 1, characterized in that the optically variable color layer contains a pure magnetic layer with the second effect pigments and a pure color layer arranged above the pure color layer with the first effect pigments. 4. Security element according to at least one of claims 1 to 3, characterized in that the first effect pigments are formed by pigments prepared on the basis of liquid-crystalline polymers. 5. The security element according to claim 1, characterized in that the first effect pigments are formed by pearlescent pigments. 6. Security element according to at least one of claims 1 to 3, characterized in that the first effect pigments are formed by interference layer pigments. 7. The security element as claimed in claim 6, characterized in that the interference layer pigments contain at least one reflection layer, one absorber layer and a dielectric spacer layer arranged between the reflection layer and the absorber layer. 8. The security element according to at least one of claims 1 to 7, characterized in that the second effect pigments are formed on the basis of high-purity iron powder. 9. The security element according to claim 1, characterized in that the second effect pigments are hard magnetic. 10. The security element according to at least one of claims 1 to 9, characterized in that the second effect pigments are non-spherical, in particular platelet-shaped. 11. A security element according to claim 10, characterized in that the ratio of the largest to the smallest diameter (diameter-to-thickness ratio) of the non-spherical second effect pigments more than 5: 1, preferably more than 10: 1, and particularly preferably between 40 : 1 and 400: 1. 12. The security element according to claim 10 or 11, characterized in that the largest diameter of the non-spherical second effect pigment ments more than 2 microns, preferably more than 5 microns, more preferably more than 10 microns and most preferably about 13 microns to about 15 microns. 13. The security element according to at least one of claims 1 to 12, characterized in that the second effect pigments are platelet-shaped and are aligned in first partial areas substantially perpendicular to the plane of the color layer to form translucent portions of the color layer. 14. The security element according to at least one of claims 1 to 13, characterized in that the second effect pigments are platelet-shaped and are aligned in second partial areas substantially parallel to the plane of the color layer to form opaque portions of the color layer. 15. Security element according to at least one of claims 1 to 14, characterized in that the second effect pigments are aligned in the form of a machine-readable magnetic coding. 16. The security element according to at least one of claims 1 to 15, characterized in that the optically variable ink layer is formed by a screen printing layer. 17. Security element according to at least one of claims 1 to 15, characterized in that the optically variable ink layer is formed by a gravure printing layer. 18. The security element according to at least one of claims 1 to 17, characterized in that the optically variable ink layer is blind-embossed. 19. A security element according to at least one of claims 1 to 18, characterized in that the color layer is formed with the pigment mixture based on a UV-curing color system. 20. A security element according to at least one of claims 1 to 19, characterized in that the color layer in addition to the first and second effect pigments further pigments, in particular isotropic pigments and / or soft magnetic pigments. 21. The security element according to at least one of claims 1 to 20, characterized in that the optically variable ink layer on a Banknote paper or on a colored background layer, preferably a background layer with a dark color, is applied. 22. Security element according to at least one of claims 1 to 20, characterized in that the optically variable ink layer is applied to a transparent or translucent film. 23. A security element according to at least one of claims 1 to 22, characterized in that the optically variable ink layer is applied to an information-carrying background layer, in particular a screen-printing layer or a gravure printing layer. 24. A security element according to at least one of claims 1 to 23, characterized in that the optically variable color layer is applied to a thermochromic background layer. 25. A security element according to claim 24, characterized in that the thermochromic background layer is designed so that disappears in their activation by increasing the temperature, the optically variable effect of the first effect pigments to the viewer. 26. A security element according to claim 24 or 25, characterized in that the thermochromic background layer over a print, in particular a print in the form of patterns and / or characters, is arranged. 27. A method for producing an optically variable security element for securing valuables, in which an at least partially translucent, optically variable ink layer is applied to a substrate containing the first optically variable effect pigments and second, magnetically alignable effect pigments, and the second effect pigments are aligned by an external magnetic field to form a motif in the form of patterns, characters or a code. 28. The method according to claim 27, characterized in that the first and second effect pigments are mixed to a pigment mixture and printed together. 29. The method according to claim 28, characterized in that the pigment mixture is printed by screen printing or gravure printing. 30. The method according to claim 27, characterized in that on the substrate first a pure magnetic layer is printed with the second effect pigments, and on the pure magnetic layer, a pure color layer is printed with the first effect pigments. 31. The method according to claim 30, characterized in that the pure magnetic layer and / or the pure color layer is printed by screen printing or intaglio. 32. The method according to at least one of claims 27 to 31, characterized in that the magnetically generated motif is fixed by UV curing of the ink layer or the pure magnetic layer. 33. Method according to claim 27, characterized in that the second effect pigments are platelet-shaped and are oriented substantially perpendicularly to the plane of the color layer in first subregions in order to form translucent subregions of the color layer. 34. Method according to claim 27, characterized in that the second effect pigments are platelet-shaped and in second subregions are aligned substantially parallel to the plane of the color layer in order to form opaque subregions of the color layer. 35. The method according to at least one of claims 27 to 34, characterized in that the second effect pigments are aligned in the form of a machine-readable magnetic coding. 36. The method according to at least one of claims 27 to 35, characterized in that the optically variable ink layer is stamped blind engraving ver. 37. Security paper with a security element according to at least one of claims 1 to 26 or a security element produced according to at least one of claims 27 to 36. 38. Security paper according to claim 37, characterized in that the security element is arranged in or above a window area or a continuous opening of the security paper. 39. Data carrier with a security element according to at least one of claims 1 to 36 or a security paper according to claim 37 or 38. 40. A data carrier according to claim 39, characterized in that the security element is arranged in or over a window area or a through opening of the data carrier. 41. A data carrier according to claim 39 or 40, characterized in that the data carrier is a banknote, a document of value, a passport, a document or an identity card. 42. Use of a security element according to one of claims 1 to 36, a security paper according to claim 37 or 38 or a data Carrier according to one of claims 39 to 41 for securing objects of any kind. 43. Apparatus for carrying out the method according to any one of the claims 27 to 36 with means for applying the optically variable ink layer to a substrate and means for magnetically aligning the second effect pigments. 44. Apparatus according to claim 43, characterized in that the means for magnetic alignment are formed by an arrangement of permanent magnets or electromagnets. 45. Apparatus according to claim 43 or 44, characterized in that the means for magnetic alignment are formed by a magnetic pressure cylinder, so that the second effect pigments are magnetically aligned only after the printing of the ink layer or the pure magnetic layer. 46. Apparatus according to claim 43 or 44, characterized in that the means for magnetic alignment are formed by a magnetic sieve, so that the second effect pigments are magnetically aligned in the screen printing when printing the ink layer or the pure magnetic layer. 47. Apparatus according to claim 43 or 44, characterized in that the means for magnetic alignment are formed by a magnetic throat plate, so that the second effect pigments are magnetically alignable in the intaglio printing of the color layer or the pure magnetic layer.