EP2465701B1 - Security element with identification marks - Google Patents

Description

The invention relates to a security element for securing valuables, which has an individualizing marking. The invention also relates to a data carrier with such a security element and to a production method for 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.

Security elements with viewing-angle-dependent effects play a special role in the authentication of authenticity since they can not be reproduced even with the most modern copiers. In this case, the security elements are equipped, for example, with optically variable elements which give the viewer a different image impression at different viewing angles and, for example, show a different color or brightness impression and / or another graphic motif depending on the viewing angle.

document WO 01/59745 A1 discloses a security element according to the preamble of claim 1.

Based on this, the present invention has for its object to provide a security element of the type mentioned above with high security against imitation and attractive visual appearance, which can ideally be checked for authenticity even by laymen.

This object is solved by the features of the independent claims. Further developments of the invention are the subject of the dependent claims. The term "solid color impression" refers to a color impression that does not change with the viewing angle. Conventional printing inks usually have such a solid color impression. In contrast, there is a color impression that changes with the viewing angle, such as the color shift effect of an optically variable layer. Such a color impression changing with the viewing angle is referred to in the context of this description as a "variable color impression". The term "variable color impression" in the context of the present invention includes everyone with the viewing angle changing and perceptible by a viewer color impression. In addition to the aforementioned color-shift effect, such a "variable color impression" can also be, for example, a viewing angle-dependent change in brightness or contrast perceptible by a viewer.

As a result of the tuning carried out according to the invention, the first subarea of the identification appears to the observer from the first viewing angle with the same color impression as the effect layer and is therefore hidden. On the other hand, it is possible to see from the first viewing angle the second partial area of the marking, which shows a different, fixed color impression and therefore stands out contrasting from the effect layer. From other viewing angles, the first portion of the marking is recognizable, since its fixed color impression then no longer coincides with their color impression due to the change in the variable color impression of the effect layer. The predetermined first viewing angle may, for example, correspond to a vertical view of the security element. It goes without saying that the principle according to the invention will not be abandoned if the effect layer and a partial area do not have the exact same color impression at a certain viewing angle, but the viewer perceives the color impression of the effect layer and the partial area as the same, although the color impression of the partial area and the effect layer only are essentially the same. For the concept according to the invention, therefore, it is ultimately decisive that the observer perceives the color impression of a specific subarea and the color impression of an effect layer as the same, without it being necessary to have an exact correspondence in the sense of defining a particular color space. As far as in the present application of the same or the same color impression of two areas of the security element according to the invention Thus, these formulations also include color impressions of two areas that are substantially the same.

It is also understood that the security element according to the invention has several areas in which an optically variable effect layer according to the invention and an optically non-variable color layer according to the invention having at least two partial areas with first and second fixed color impressions are present. It is conceivable, e.g. a security element having in a first area a first effect layer and an optically non-variable color layer with first and second partial area, wherein the first partial area conveys a first solid color impression and the second partial area a second solid color impression. In a second region of this security element, a second optically variable effect layer is arranged, which is combined with a further optically non-variable color layer having two partial areas and two fixed color impressions, the color impression being different from the first and second optically variable effect layer and from the respectively assigned partial areas can be. Also, the first and second optically variable effect layer and the associated subregions may have different structures according to the invention.

The subregions of the color layer and the effect layer are matched to one another such that the variable color impression of the effect layer corresponds to the second fixed color impression at a predetermined second viewing angle. The predetermined second viewing angle may, for example, correspond to an oblique view of the security element. In this case, only the second subarea of the marking can be seen when viewed vertically, while only the first subarea of the marking can be seen when viewed obliquely. The other one Subarea remains hidden to the viewer due to the color match with the effect layer.

The effect layer is essentially transparent. In one variant, a laser-sensitive covering intermediate layer is arranged between the effect layer and the color layer, and the marking is formed by recesses or local transparent modifications of the intermediate layer, which are each produced by the action of laser radiation. In the areas which are not exposed to laser radiation, the effect layer is then present against the background of the covering intermediate layer, while in each case the view of the color layer arranged beneath the effect layer and the intermediate layer is released in the areas acted upon by the recesses or the transparent modification areas.

It is understood that the above-described variant with essentially transparent formed effect layer and laser-sensitive, opaque intermediate layer between this effect layer and a color layer in principle also executable with an effect layer, the laser radiation is not absorbed and semitransparent or even opaque. As described above, by the application of laser radiation, the Intermediate layer provided by recesses or local, transparent modifications, so that in turn result for the viewer interesting Farbkippeffekte invention.

The optically variable appearance of the effect layer is especially effective when the opaque interlayer is dark, especially black. The intermediate layer can contain, for example, in a transparent binder an IR absorber, such as carbon black CIPB1.7 or graphite, which is ablated when exposed to laser radiation with an infrared laser. Other suitable materials for the laser sensitive opaque interlayer, in particular the candidate absorbent blend components, can be found in the references WO 2005/108110 A1 . DE 10 2008 049 512 A1 and DE 10 2006 008 247 are taken from the disclosures of which are included in the present description.

The effect layer is substantially transparent, and in one variant the color layer itself comprises at least one laser-sensitive color mixture, as described, for example, in the cited references DE 10 2008 049 512 A1 . DE 10 2006 008 247 and WO 2005/108110 A1 is described. The marking is formed in this embodiment by local color changes in the laser-sensitive color mixture, which are generated by the action of laser radiation. For example, the color mixture may contain first and second colored pigments, wherein the second colored pigments are present in a multiplicity of core-shell particles, the shell of each of which is surrounded by an ablation-promoting functional layer, as in US Pat DE 10 2008 049 512 A1 described. By laser application, the second colored pigments can then be removed from the color mixture, so that the color impression in the marked areas only determined by the first pigments. In order to produce different solid color impressions, different first colored pigments may be provided in different partial areas of the color layer, or the color mixture may contain a plurality of colored pigments which can be removed at different laser intensities.

In a preferred embodiment of the invention, the color layer shows a color gradient between the first and second solid color impression. Such a color gradient can be generated for example by a plurality of color elements with different colors. In a particularly expedient design, however, the color gradient is produced by a multiplicity of juxtaposed first and second color elements, which respectively show the first and second fixed color impressions, and their area proportions vary spatially in order to produce a quasi-continuous color transition from the first to the second color impression. The first and second color elements may in particular be juxtaposed color stripes or halftone dots.

Of course, it is also conceivable that, for example, for an optically non-variable ink layer with three color impressions a color between the first and second and between the second and third color impression is produced by the fact that by means of the method described above, a color gradient between the respective solid color impressions is produced. At present, however, the above-described embodiments with a color gradient between first and second solid color impression of a color layer with two partial regions are particularly preferred because of the simpler manufacture and the impressive tilting effect resulting for the viewer.

Also conceivable is an embodiment in which the optically non-variable ink layer additionally comprises another security feature, such as e.g. Mikrotext, which can be additionally used as an authenticity feature, for example in the field of customization.

Furthermore, it is conceivable that an effect layer has an optically variable diffraction structure, which shows the variable color impression according to the invention on the basis of their specific diffraction structures.

In all embodiments, the color layer and / or the effect layer may contain a feature substance, in particular a magnetic, electrically conductive, luminescent or infrared-absorbing feature substance. If an intermediate layer is provided, it may also contain such a feature substance.

The optically variable effect layer preferably contains single or multilayer interference pigments or cholesteric liquid crystal pigments.

Such interference pigments have, as well as certain applicable within the scope of this invention surface layer structures, optically effective interference layers. Such interference layers typically have a thin-film structure and, for example in the case of a multilayer thin-film structure, comprise a reflection layer, an absorber layer and one or more intervening dielectric spacer layers and are based, for example, on mica, on SiO ₂ or on Al ₂ O ₃ . Such interference layers are referred to as one or more layers according to the number of dielectric layers. Printing inks with interference layer pigments, for example, under the name Iriodin ^® (single layer) or Colorcrypt ^® (multi-layer) marketed by Merck KGaA. Inks with multilayer interference layer pigments, for example, are also sold under the name OVI ^® of SICPA.

Also, effect layers with holographic pigments or with pigments having a constant diffraction structure come into consideration. In particular, holographic pigments can be prepared by comminuting holographic films. They can be both transparent and opaque.

In a development of the invention, the individualizing marking is continued outside the overlapping area, in particular by a local change of a standard color or a local change of a substrate, for example by a foaming or blackening of the substrate. The marking or the security element can thereby be integrated into the design of the data carrier to which the security element is applied. Such a continuation of the marking in the surrounding data carrier is particularly well feasible if the security element, as proposed according to the invention, is subsequently individualized. In general, the individualizing marking outside the covering area can also be continued by the fact that a part of the marking is already arranged outside the covering area. As a rule, however, register errors occur during such a continuation of the individualizing mark, so that the embodiment described above with continuation of the marking in the surrounding data carrier by subsequent individualization is very particularly preferred.

The individualizing marking can be executed rasterized in advantageous embodiments of the invention and then preferably represent a screened grayscale image or a screened color halftone image.

The color layer and the effect layer can be coated, at least in the covering area, with a lacquer layer which compensates for a different matt or gloss effect in the area of the marking. In this way it can be avoided that marking parts, which should actually be provided from a certain viewing angle due to their color match with the effect layer, can still be recognized due to different matt or gloss effect.

Also, by certain additives in the optically non-variable ink layer can be avoided that identification parts, which should actually be hidden due to their color match with the effect layer from a certain viewing angle, are still recognized by the viewer under certain lighting and observation conditions. These additives may, for example, be silvery-shimmering pigments which give the optically non-variable color layer a shimmering color impression which corresponds to the color impression of the optically variable effect layer arranged above it with e.g. also shimmering, optically variable pigments are very well approximated. In other words, the glimmer of the areas in question distracts the eye of the observer from the slight deviation of the color impressions that may be present, whereby the color impressions of these areas subjectively perceived by the observer are the same.

The partial regions of the marking with the first and second color impression preferably make reference to one another or to each other Information. For example, the information of the first sub-range repeat the information of the second sub-range or supplement to a total information.

Advantageously, the security element comprises a substrate on which the color layer, any intermediate layer and the effect layer are arranged in this order. Suitable substrate material is any type of paper, in particular cotton paper or even paper, which contains a proportion x polymeric material in the range of 0 <x <100% by weight. Furthermore, the substrate material may also be a plastic film, for example a polyester film. Such a film may 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. Since the security element according to the invention is designed for observation in a top view, the substrate is preferably opaque. Of course, a transparent or translucent substrate can be used if, for example, the optically non-variable ink layer is opaque, or else the security element is placed on a reflective, in particular white background. Such a transparent or translucent substrate may also be a plastic film, which is arranged in the region of a window-like opening in a data carrier. At present, however, opaque or substantially opaque substrate materials are preferred for the security element since the security element of the invention is suitable for the observer e.g. Because of their higher color saturation they are usually more attractive.

The invention also encompasses a data carrier with a security element of the type described. The data carrier may in particular be a value document, such as a banknote, in particular a paper banknote, a banknote or foil composite banknote, but may also be an identification card, such as a credit card, a bank card, a cash card, an authorization card, an identity card or a passport personalization page.

The individualizing marking is advantageously continued beyond the security element into the data carrier. This can be done for example by the foaming or blackening of the data carrier substrate or by changing a layer present on the data carrier, such as the local change of a color layer or the demetallization of a metal layer. Due to the subsequent individualization by means of laser application, this continuation can be carried out in register.

The invention further relates to a method for producing a security element according to one of claims 1 to 7.

The individualizing marking is thereby generated by laser application, in particular with an infrared laser, such as a CO ₂ laser, Nd: YAG laser or Nd: YVO ₄ laser. The individualizing marking is advantageously produced only after the production of the layer sequence of substrate, ink layer and effect layer in a separate production step.

The individualization by means of laser application enables a subsequent individualization of the security element, so that the individualizing information at the time of production of the layer sequence does not yet have to be known. Rather, the individualization can be made later, for example when applying the security element to a specific value document. In this case, for example, the serial number of a banknote can be detected via a reading device and the read serial number can be inscribed as an individualizing identifier in the security element. Also, in the case of a subsequent individualization, the marking can continue beyond the area of the security element with register accuracy in the surrounding data carrier and thus the Counterfeit security of the system security element / data carriers can be further increased.

The color layer and / or the effect layer will preferably be applied in a printing process. Particularly preferably, both layers are printed. In principle, the effect layer can be applied using all common printing methods, such as screen printing, flexographic printing, gravure printing and intaglio printing. However, a screen or flexographic printing process is currently preferred. The gravure printing process is also particularly advantageous for plastic film-based substrates with and without a pressure-receiving layer.

The different subregions of the optically non-variable ink layer can also be applied in principle with virtually all common printing processes. Preferably, however, the offset printing method is used, wherein the application of the color layer in the wet-offset, dry-offset and very particularly preferably in the indirect high-pressure process can take place. Advantageously, the indirect high-pressure process for the color layer and the flexographic printing process for the effect layer are used in a printing process which then comprises, for example, three partial printing steps (two partial printing steps for the ink layer, one partial printing step for the effect layer).

If a laser-sensitive opaque intermediate layer is provided, it is also advantageously printed, with the abovementioned printing methods being able to be used. With particular advantage, all layers of the layer composite are thus produced by printing processes, while the individualization takes place by laser application.

It is also conceivable, in principle, to apply an opaque white layer to a substrate in predetermined areas when the color layer and / or effect layer is not sufficiently opaque, and to subsequently arrange the color layer, optionally the interlayer and the effect layer above it. Such an opaque white layer can be applied to the substrate with relatively high register accuracy by means of a printing process known per se, which leads to a high color saturation in the areas of opaque white in the finished security element.

In a preferred embodiment, the security element with the layers according to the invention and individualizing marking is produced on a film, in particular a plastic film, and the security element produced in this way is transferred to the target substrate by means of hot or cold foil application (hot or cold film transfer method) as film strip or foil patch. Of course, it is also conceivable that by means of a suitable method the layers according to the invention are produced on an intermediate carrier and only the layers according to the invention are transferred to the target substrate.

In a further alternative embodiment, it is further provided that the optically non-variable ink layer is arranged on a target substrate and the optically variable effect layer is transferred to the ink layer by means of a suitable transfer process for forming the security element according to the invention. In turn, hot or cold film transfer processes and similar techniques can be used as the transfer process.

It is understood that in the transfer methods described above, an optionally required intermediate layer between the effect layer and the color layer can either be transferred to the target substrate with the entire security element or arranged on the color layer or transferred to the color layer with the effect layer.

It should also be mentioned that the optically non-variable color layer may have an additive which promotes the generation of the individualizing marking by ablation, in particular laser ablation, by forming a separating layer to the effect layer upon exposure to electromagnetic radiation, in particular laser application. Such an additive may be e.g. to act at low temperatures melting waxes, especially carnauba wax.

In a corresponding manner, the effect color may contain an additive which, when the individualizing marking is generated by ablation, in particular laser ablation, advantageously reduces the binding forces to the optically non-variable color layer. The additive of the effect color may also be, for example, waxes melting at low temperatures, in particular carnauba wax.

Of course, it is also conceivable that the optically non-variable color layer and the effect layer contain a complete ablation-promoting additive, as described above.

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

Fig. 1

eine schematische Darstellung einer Banknote mit einem erfindungsgemäßen Sicherheitselement,

Fig. 2

das visuelle Erscheinungsbild des Sicherheitselements der Fig. 1, in (a) bei senkrechter Betrachtung und in (b) bei schräger Betrachtung,

Fig. 3

in (a) und (b) jeweils schematisch einen Querschnitt des Sicherheitselements der Fig. 2 zur Erläuterung des Schichtaufbaus und des Zustandekommens des digitalen Informationswechsels,

Fig. 4 bis 7

verschiedene vorteilhafte Abwandlungen des Sicherheitselements der Fig. 3,

Fig. 8

ein Sicherheitselement nach einem weiteren Ausführungsbeispiel der Erfindung schematisch in Aufsicht,

Fig. 9

einen Farbverlauf zur Verwendung in dem Sicherheitselement der Fig. 8, und

Fig. 10

einen Querschnitt durch das Sicherheitselement von Fig. 8 entlang der Linie X-X.

Show it:

Fig. 1

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

Fig. 2

the visual appearance of the security element of the Fig. 1 , in (a) when viewed vertically, and in (b) when viewed obliquely,

Fig. 3

in (a) and (b) each schematically a cross section of the security element of Fig. 2 to explain the layer structure and the realization of the digital information change,

Fig. 4 to 7

Various advantageous modifications of the security element of Fig. 3 .

Fig. 8

a security element according to a further embodiment of the invention schematically in plan view,

Fig. 9

a gradient for use in the security element of Fig. 8 , and

Fig. 10

a cross section through the security element of Fig. 8 along the line XX.

The invention will now be explained using the example of security elements for banknotes. Fig. 1 shows a schematic representation of a banknote 10 with a security element 12 according to the invention. The security element 12 shows an optically variable appearance and is also provided with a banknote individualizing marking 14, from which depending on the viewing angle only a portion can be seen.

The individualizing identifier 14 can be, for example, the serial number or a repetition of the denomination 15 of the banknote. In the exemplary embodiment, the individualizing identifier 14 is formed for the sake of simplicity of illustration by the number sequence "3456".

To illustrate the only partial recognizability of the label 14 from different viewing directions shows Fig. 2 in (a) the visual appearance of the security element 12 when viewed perpendicularly and in (b) viewed obliquely at an angle of, for example, about 45 °.

The marking 14 contains two partial areas 16, 18, each of which has a different, fixed color impression. As explained above, the term "solid color impression" designates a color impression that does not change with the viewing angle while interacting with the viewing angle changing color impression is referred to as a "variable color impression", wherein the term "variable color impression" also includes, for example, brightness or contrast changes.

The marking 14 has in its first portion 16, which is formed in the form of the numerical sequence "34", the solid color green, and in its second portion 18, which is formed in the form of the numerical sequence "56", the solid color impression magenta.

The surrounding area 20 of the marking 14 shows no fixed color impression, but has a color shift effect with a variable color impression, which changes in the embodiment of magenta when viewed perpendicularly to green at oblique viewing.

At the in Fig. 2 (a) illustrated vertical consideration of the solid color impression magenta of the portion 18 and the variable color impression magenta of the surrounding area 20 coincide, while the partial area 16 with its solid color green is in clear contrast to the surrounding area 20. An observer thus sees only the numerical sequence "34" of the green subarea 16 in front of a uniform magenta background 18, 20 when viewed vertically.

When viewed obliquely at an angle of 45 °, as in Fig. 2 (b) illustrates, the fixed color impression green of the partial area 16 and the variable color impression green of the surrounding area 20 coincide, while now the partial area 18 with its solid color impression magenta forms a clearly perceptible contrast to the surrounding area 20. An observer thus sees with oblique view only the number sequence "56" of the portion 18 in magenta in front of a uniform green background 16, 20.

When going back and forth, the security element 12 presents the viewer with a digital information exchange between the partial information "34" and "56", thereby enabling easy verification even by laymen. If the observer quickly tilts the security element 12 back and forth, the entire designation "3456" becomes recognizable due to the after-image effect of the human eye and the gradual color change of the color-shifting effect.

The layer structure of the security element 12 and the occurrence of the digital information exchange will now be described with reference to FIG Fig. 3 explained in more detail.

Fig. 3 (a) schematically shows a cross section of the security element 12 in the region of the marking 14. The security element 12 has a substrate 30, which may be formed for example by a foil, but also by the banknote paper of the banknote 10 itself. On the substrate 30, an optically non-variable ink layer 32 is first printed, which contains a first portion 34 with the solid color impression magenta and a second portion 36 with the fixed color green.

On the color layer 32 is a laser-sensitive, black intermediate layer 38 and the intermediate layer 38, a transparent, optically variable effect layer 40 is printed, which shows against the background of the black intermediate layer 38, the desired color shift effect of magenta when viewed perpendicularly to green at oblique viewing.

After the production of the aforementioned layer sequence, the black intermediate layer 38 and the effect layer 40 were locally ablated in the partial areas 16, 18 of the marking 14 by laser application and the security element 12 was thereby individualized.

Fig. 3 (a) shows a laser ablation of the layers 38,40, it is also possible by laser irradiation to evaporate layer areas or convert it into a transparent or other color modification.

After laser individualization, the color impression is determined by the color impression of the partial areas 34, 36 of the color layer 32 in the uncovered partial areas 16, 18 in vertical viewing 42, so that the color impression green (G) in the partial area 16 and the partial area 18 Color impression magenta (M) yields. In the surrounding area 20, the optically variable effect layer 40 against the background of the black intermediate layer 38 shows the color impression magenta (M) when viewed perpendicularly so that, when viewed vertically, the total in Fig. 2 (a) shown visual impression results.

Fig. 3 (b) illustrated in the oblique view 44. In the exposed portions 16,18 the color impression is determined unchanged by the solid color impression of the portions 34, 36 of the ink layer 32, so that the portion 16 as in vertical view the color impression green (G) and the portion 18 shows the color impression magenta (M). In the surrounding area 20, the optically variable effect layer against the background of the black intermediate layer 38 produces the color impression green (G) when viewed obliquely, so that when viewed obliquely, the in Fig. 2 (b) shown visual impression results.

A particular advantage of the security element according to the invention is that the color layer 32, the intermediate layer 38 and the effect layer 40 on the one hand all by printing processes and thus can be easily and inexpensively generated and on the other hand, the individualization by means of laser application allows subsequent customization of the security element. The information to be presented with the identification must therefore not yet be known at the time of manufacture, but can only be generated when the security element is used.

The FIGS. 4 to 7 show various advantageous modifications of the security element of Fig. 3 ,

The security element 12 of the embodiment of Fig. 4 corresponds largely to the security element of Fig. 3 However, the black intermediate layer 38 is not removed in the identification portions 16,18 by the laser application, but only in a transparent modification 46 has been converted. The effect layer 40 can be ablated in this variant by the laser radiation, as in Fig. 3 shown, or even persist, as in Fig. 4 shown. The latter is particularly suitable when the color impressions of the ink layer areas 34, 36 are relatively bright, since the optically variable effect layer 40 in the marking areas 16, 18 then hardly stands out against its light background. It is also conceivable that the effect layer 40 is likewise only modified in the region above the identification subregions 16, 18.

Fig. 5 shows a further embodiment of the invention, in which the security element 12 has a covering, optically variable effect layer 48. Such opaque effect layers can be produced, for example, with printing inks having multilayer interference-layer pigments, as they are sold under the name OVI ^® by the company SICPA. In this case, the marking 14 is formed by recesses 16, 18 or alternatively by local transparent modifications of the effect layer 48 produced by the action of laser radiation.

In the further embodiment of the Fig. 6 the color layer 50 is formed from a laser-sensitive color mixture, from which a color component can be removed by the action of laser radiation. Such color mixtures may contain, for example, first colored pigments and laser-sensitive core-shell particles with a second colored pigment, the core-shell particles being provided with an ablation-promoting functional layer. In the non-laser-applied region 20, both colored pigments are then present and together produce a dark background for a transparent, optically variable effect layer 40. In the laser-applied region 16, the laser-sensitive core-shell particles with the second colored pigments are removed from the color layer 50, so that the color impression is determined there only by the first colored pigment.

In the second laser-loaded area 18, for example, another first colored pigment may be present in the ink layer 50, thereby producing a different marking ink by laser application.

Alternatively, the color mixture of the color layer 50 may also contain a plurality of laser-sensitive core-shell particles with a second or third colored pigment, which are removed from the mixture by different ablation-promoting functional layers at different intensities of laser intensity. In the non-laser-applied region 20 all three colored pigments are then present and produce a dark background for the transparent, optically variable effect layer 40. In the laser-applied region 16 is at lower Laser intensity, for example, only the laser-sensitive core-shell particles removed with the third color pigment, so that the color impression is determined there by a superposition of the first and second colored pigments (first solid color impression). In the laser-applied region 18, the laser-sensitive core-shell particle with the second colored pigment is additionally removed at high laser intensity, so that the color impression there is determined only by the first colored pigment (second solid color impression). Again, with a suitable choice of the colored pigments, the desired color impressions in the first and second partial areas 16, 18 of the marking can be generated.

Another variant of the invention is in Fig. 7 shown. In this exemplary embodiment, the color layer 52 is formed from a layer 54 of a non-laser-sensitive fixed color and a layer 56 applied above it, which also contains laser-sensitive core-shell particles with a second colored pigment in addition to first colored pigments, the core-shell particles having an ablation-promoting Functional layer are provided. In the laser-loaded region 16, the laser-sensitive core-shell particles with the second colored pigment are removed, so that the color impression there is determined by the first colored pigment (first solid color impression). In the laser-applied region 18, the entire layer 56 has been ablated at high laser intensity, so that the color impression is given there by the underlying fixed-color layer 54 (second solid color impression).

Fig. 8 shows a security element 60 according to another embodiment of the invention, in which the label 62 in the form of the words "50 Euro" has a gradient with smooth transitions. For example, the color impression of the label 62 may slowly change from green to magenta from top to bottom. It should be emphasized that it This color gradient is not a variable color impression since the color impression remains unchanged at every point of the curve when the security element 60 is tilted. Rather, the fixed color impression itself changes quasi-continuously from the upper edge to the lower edge of the marking 62.

In the exemplary embodiment, this quasi-continuous color gradient is produced with the aid of only two colors (green and magenta) by the successive change of the area fraction of the colors in adjacent color stripes. Fig. 9 shows a gradient 70 with a plurality of green color stripes 72 and magenta color stripes 74, which are arranged in a one-dimensional grid with grid spacing d. Within each raster d, the area fraction g of the green color stripes 72 decreases from 100% to 0% from top to bottom. Accordingly, the area ratio m = 100% -g of the magenta color stripes 74 increases from top to bottom from 0% to 100%. If the grid spacing d is chosen to be small enough, the result is an infinitely variable color progression 70 from green to magenta for the eye. In practice, a few raster periods, for example 6, 8 or 10 raster grids, are usually sufficient to produce a soft color gradient for the eye.

Fig. 10 now shows a cross section through the security element 60 along the line XX of Fig. 8 , As in Fig. 10 a color layer 82 is printed on the substrate 80, which in the region of the marking 62 the color gradient 70 of Fig. 9 contains. The color impression changes from the first subregion 84 to the second subregion 86 quasi-continuously from the solid color impression magenta to the solid color impression green.

A laser-sensitive, black intermediate layer 38 is printed on the color layer 82 and a transparent optically variable effect layer 40 is printed on the intermediate layer 38, which has a color shift effect of magenta when viewed perpendicularly to green when viewing obliquely against the background of the black intermediate layer 38. After the production of said layer sequence, the black intermediate layer 38 and the effect layer 40 in the form of the lettering "50 euros" were locally ablated by laser application and the security element 60 was thereby provided with the marking 62.

When viewed vertically, the effect layer 40 appears in the surrounding region 20 of the marking against the background of the black intermediate layer 38 with a magenta color impression and thus with the same color impression as the lower part 62-U of the marking 62. Therefore, the marking 62 is only the middle one when viewed vertically and upper part to recognize.

When the security element 60 is tilted in the direction of the arrow 64, the color impression of the effect layer 40 in the surrounding area 20 initially changes to a mixed color magenta / green, and thus to the same color impression that the middle part 62-M of the marking shows. When further tipping the color impression of the effect layer 40 then changes to green, so the same color impression that shows the upper part 62-O of the label.

When tilted in the direction of arrow 64 so first disappears the middle and then the upper part of the label 62 due to the lack of contrast to the surrounding area 20 for the viewer, while the lower, magenta part 62-U is visible. In the fast back and forth are due to the inertia of the human eye again all parts of the label 62 recognizable.

That in the FIGS. 8 to 10 shown and discussed above security element 60 can also be considered as a security element having a plurality of sub-areas each having a fixed color impression in a particular sub-area, as required by the invention.

LIST OF REFERENCE NUMBERS

10

bill

12

security element

14

Labelling

15

Denomination

16, 18

subregions

20

surrounding area

30

substratum

32

optically non-variable color layer

34, 36

subregions

38

interlayer

40

transparent optically variable effect layer

42

vertical supervision

44

weird contemplation

46

transparent modification

48

covering optically variable effect layer

50

coat of paint

52

coat of paint

54

non-laser-sensitive fixed color

56

layer

60

security element

62

Labelling

62-O, 62-M, 62-U

marking parts

64

tilt direction

70

color gradient

72

green color stripes

74

magenta color stripes

80

substratum

82

coat of paint

84, 86

subregions

Claims (10)

1. A security element (12) for securing value objects (10), with

   - an optically variable effect layer (40) conveying different color impressions at different viewing angles,

   - and an optically non-variable ink layer (32) covered by the effect layer at least in an overlap region and containing there at least one first partial region (34) with a first permanent color impression and a second partial region (36) with a different second permanent color impression, wherein

   - the security element has an individualizing marking (14) that is produced at least in the overlap region of the effect layer and the ink layer and shows the first and/or second permanent color impression respectively in a partial region (16, 18), characterized in that the security element has a substrate (30) on which the optically non-variable ink layer and the optically variable effect layer are arranged in this order, and that

   - the partial regions of the ink layer and the effect layer are mutually matched such that the variable color impression of the effect layer at a predetermined first viewing angle corresponds to the first permanent color impression and the variable color impression of the effect layer at a predetermined second viewing angle corresponds to the second permanent color impression, and that

   - the effect layer is configured to be substantially transparent, a laser-sensitive opaque intermediate layer (38) is arranged between the effect layer and the ink layer, and the marking is formed by gaps or local transparent modifications of the intermediate layer which are produced by the action of laser radiation.
2. A security element for securing value objects, with a substrate on which an optically non-variable ink layer and an optically variable effect layer are arranged in this order, wherein

   - the optically variable effect layer conveys different color impressions at different viewing angles,

   - the optically non-variable ink layer is covered by the effect layer at least in an overlap region and there contains at least one first partial region with a first permanent color impression and one second partial region with a different second permanent color impression,

   - the security element has an individualizing marking that is produced at least in the overlap region of the effect layer and the ink layer and shows the first and/or second permanent color impression respectively in a partial region,

   - the partial regions of the ink layer and the effect layer are mutually matched such that the variable color impression of the effect layer at a predetermined first viewing angle corresponds to the first permanent color impression and the variable color impression of the effect layer at a predetermined second viewing angle corresponds to the second permanent color impression, and

   - the effect layer is configured to be substantially transparent, the ink layer comprises at least one laser-sensitive ink mixture and the marking is formed by local color modifications in the laser-sensitive ink mixture which are produced by the action of laser radiation.
3. The security element according to any of the claims 1 or 2, characterized in that the ink layer shows a color gradation between the first and the second permanent color impression, wherein the color gradation is preferably produced by a multiplicity of first and second color elements arranged next to each other, in particular color stripes or grid points which respectively show the first or second permanent color impression and the surface proportions of which vary spatially in order to produce a quasi-continuous color gradation from the first to the second color impression.
4. The security element according to any of the claims 1 to 3, characterized in that the ink layer and/or the effect layer contains a feature substance, in particular a magnetic, electroconductive, luminescent or infrared-absorbing feature substance.
5. The security element according to any of the claims 1 to 4, characterized in that the effect layer contains single-layer or multilayer interference pigments or cholesteric liquid crystal pigments.
6. The security element according to any of the claims 1 to 5, characterized in that the individualizing marking is continued outside of the overlap region, in particular by a local modification of a standard color or a local modification, such as foaming or blackening of a substrate, and/or that the individualizing marking is executed in grid fashion and preferably represents a gridded gray-scale image or a gridded colored halftone image.
7. The security element according to any of the claims 1 to 6, characterized in that the ink layer and the effect layer are coated at least in the overlap region with a lacquer layer that compensates a different matte or gloss effect in the region of the marking, and/or that the partial regions of the marking with the first and second color impression represent information items which are interrelated or complement each other.
8. A data carrier, in particular a value document, such as a banknote, identification card and the like, with a security element according to any of the claims 1 to 7, wherein preferably the individualizing marking is continued beyond the security element into the data carrier in exact register.
9. A method for manufacturing a security element according to any of the claims 1 to 7, in which

   - a substrate is made available,

   - an optically non-variable ink layer is applied which contains in an overlap region at least one first partial region with a first permanent color impression and one second partial region with a different second permanent color impression,

   - an optically variable effect layer is applied which conveys different color impressions at different viewing angles and which covers the optically non-variable ink layer in the overlap region,

   - wherein the partial regions of the ink layer and the effect layer are mutually matched such that the variable color impression of the effect layer at a predetermined first viewing angle corresponds to the first permanent color impression and the variable color impression of the effect layer at a predetermined second viewing angle corresponds to the second permanent color impression, and

   - at least in the overlap region of the effect layer and the ink layer an individualizing marking is produced which shows respectively in a partial region the first and/or second permanent color impression, namely by laser application, in particular with an infrared laser, such as a CO₂ laser, Nd:YAG laser or Nd:YVO₄ laser.
10. The method according to claim 9, characterized in that the ink layer and/or the effect layer, preferably both layers, are applied by a printing method.

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