Security element with combination security feature

Abstract

The invention relates to a security element for securing security papers, valuable documents and other data carriers with a combination security feature (16) which contains a colored image motif in the form of a flag, wherein - the combination security feature (16) shows the flag motif (20) with a 2D appearance under normal lighting with visible light, and - when using hybrid lighting with visible light and UV light, the flag motif appears with a 3D appearance as a moving, especially waving flag (25), - wherein the combination security feature (16) comprises a body color layer (32, 34) with at least two visually visible body colors for generating the 2D appearance of the flag motif and comprises at least one luminescent color layer (36) arranged above and / or below the body color layer (32, 34), which, when excited with UV light, generates a brightness modulation superimposed on the 2D appearance, giving the flag motif a 3D appearance as a moving, in particular waving, flag.

Description

[0001] The invention relates to a security element for securing security papers, value documents and other data carriers with a combination security feature, a method for producing such a security element and a value document or security document with such a security element.

[0002] Data storage devices, such as valuables or identification documents, as well as other valuable items such as branded goods, are often provided with security features for security purposes. These allow verification of the authenticity of the data storage devices and also serve as protection against unauthorized reproduction. In this context, luminescent substances are known to be used to protect valuables or identification documents. The presence of the luminescent substances can then be verified using a UV lamp, for example.

[0003] For example, from document EP 1 567 358 B2, security prints with several areas are known which show the same colour impression under white light, for example daylight, but which show different colour impressions in luminescence upon additional UV excitation.

[0004] Furthermore, it is known that the color impressions of luminescent printing inks generally change due to aging and environmental factors, and that both the intensities and color impressions of different luminescences can change at different rates. Conventional luminescent features of security elements therefore cannot depict motifs that are easily recognized by a viewer due to their color impression or multi-color combination, such as white color areas or combinations of national colors.

[0005] Based on this, the object of the invention is to overcome the disadvantages of the prior art and, in particular, to provide a data carrier with a luminescent security element with a high level of forgery security and an attractive visual appearance. Summary of the invention:

[0006] 1. (First aspect of the invention): Security element for securing security papers, value documents and other data carriers with a combination security feature containing a coloured image motif in the form of a flag, wherein - the combination security feature displays the flag motif with a 2D appearance under normal visible light illumination, and - when illuminated with hybrid visible light and UV light, the flag motif has a 3D appearance, showing a moving, particularly waving, flag, - wherein the combination security feature comprises a body color layer with at least two visually visible body colors for generating the 2D appearance of the flag motif, and at least one luminescent color layer arranged above and / or below the body color layer, which, when excited with UV light, generates a brightness modulation superimposed on the 2D appearance, giving the flag motif a 3D appearance as a moving, in particular waving, flag. For the purposes of this description, normal lighting refers to visible light in the spectral range from 380 nm to 780 nm, in particular natural or artificial daylight, or room lighting. UV light refers to light in the wavelength range from 200 nm to 380 nm, in particular light with emission peak wavelengths at 254 nm or 365 nm.

[0007] The combination security feature can also be visible under pure UV illumination without normal lighting, whereby a change in information occurs when changing from normal lighting to UV illumination, namely a change from a 2D appearance under normal lighting to a 2D appearance with brightness modulation under UV illumination.

[0008] 2. (Preferred embodiment): Security element according to paragraph 1, characterized in that the luminescent color layer emits white luminescent light upon UV excitation.

[0009] 3. (Preferred embodiment): Security element according to paragraph 1, characterized in that the luminescent color layer emits white luminescent light and additionally reddish or red and / or yellowish or yellow luminescent light upon UV excitation.

[0010] 4. (Preferred embodiment): Security element according to at least one of paragraphs 1 to 3, characterized in that the luminescent color layer is transparent or translucent in the visible spectral range, in particular that the luminescent color layer is not visually perceptible under normal lighting without UV component.

[0011] 5. (Preferred embodiment): Security element according to at least one of paragraphs 1 to 4, characterized in that the luminescent color layer contains a mixture of red, green and blue emitting luminescent pigments which have high light and environmental resistance due to a uniform coating material.

[0012] 6. (Preferred embodiment): Security element according to at least one of paragraphs 1 to 5, characterized in that the brightness modulation creates a 3D appearance in which elements closer to the observer shine brighter and elements further away shine less brightly.

[0013] 7. (First aspect of the invention): A method for producing a security element according to any one of paragraphs 1 to 6, in which on a substrate - a body colour layer with at least two visually visible body colours is applied to create the 2D appearance of the image motif, and - a luminescent color layer is applied above and / or below the body color layer, which, when excited with UV light, creates the brightness modulation superimposed on the 2D appearance.

[0014] 8. (Preferred embodiment): Method according to paragraph 7, characterized in that the body colors are applied with a number of printing plates of a printing press, and a white emitting luminescent ink layer is applied with a single further printing plate of the / a printing press, or that a colored emitting luminescent ink layer is applied with several, in particular two or three further printing plates of a printing press.

[0015] Preferably, all of the printing steps mentioned are carried out on the same printing machine, but in principle it is also possible to carry out the different printing steps on different printing machines.

[0016] 9. (Preferred embodiment): Method according to paragraph 7 or 8, characterized in that the luminescent color of the luminescent color layer is applied with locally different surface density to produce the brightness modulation.

[0017] 10. (Third aspect of the invention): A valuable document or security document comprising a security element according to any one of paragraphs 1 to 6.

[0018] The value document can be, in particular, a banknote, a certificate, a voucher, a check, a high-value admission ticket, a tax stamp, high-value product packaging, or a brand protection item. The security document can be, in particular, an identification card, such as an ID card, a data page for an ID document, a bank card, a credit card, or a driver's license.

[0019] Monitoring of the luminescence color control during production can be advantageously carried out using a handheld luminescence measuring device.

[0020] For the luminescent color layer, the present invention advantageously uses coordinated luminescent pigments that have a uniform shell material for the emission colors red, green, and blue, thus offering essentially the same printability. Due to the uniform shell material, the pigments also exhibit virtually identical stability and aging properties. Therefore, even if the emission intensity of the pigments decreases over time, the reduction occurs concurrently for the different colored pigments, so that the overall color impression of the mixed colors produced by the pigments, in particular the mixed color white, remains virtually unchanged. The low emission intensity can be compensated, for example, by a higher intensity of the UV excitation radiation.

[0021] In the present invention, white luminescence light can be generated, for example, from an RGB luminescence color mixture and can represent “warm white” luminescence light (low color temperature, below 4000 K) or “cold white” luminescence light (high color temperature, above 4000 K).

[0022] The body and luminescent inks mentioned can be used in both UV-curing and conventional oxidative drying inks.

[0023] It is particularly advantageous to print the fluorescent or luminescent ink on the body color motif, as this requires significantly less luminescent dye than if the fluorescent or luminescent ink is printed in the body color or under the body color.

[0024] An alternative design option is to use inkjet inks or intaglio printing to create a brightness gradient on a body color that is visually visible under normal lighting. For example, the body color of the flag motif (with a 2D appearance) can be printed with inkjet inks, and the luminescent ink layer can be combined with it using offset printing. Offset printing can be performed as an upstream or downstream process. Furthermore, it is also possible to print both the body color and a luminescent ink with inkjet. With intaglio printing, brightness modulation can be achieved by depth modulation of the engraving depth.Using fluorescent effects from a white-emitting luminescent ink layer printed on foil, any national flag can be transformed into 3D flags. These are then simply inkjet-applied to the luminescent layer, the back of the foil, or other suitable foils / substrates, and then laminated together to form a card. Composite structures consisting of a banknote substrate and foil element, as an applied foil strip or hybrid substrate, are also possible.

[0025] As another alternative design, the luminescent ink layer can consist of three sublayers, each containing one of the red, green, and blue-emitting luminescent pigments. This can further enhance the brilliance of the body color. For example, areas where a red body color is visible in daylight are more strongly enhanced by red fluorescence. However, this requires a higher print unit footprint and greater ink management effort.

[0026] For the purposes of the invention, the term "flag" or "flag motif" encompasses not only rectangular flags, but all types of flags and banners, such as cantilever flags, hoist flags, hanging flags, mast flags, standards, banner flags, scrolls, pennants, gonfalons, or double poles. Furthermore, the term also includes other forms of fabric, ribbons, and cloth, such as tablecloths, curtains, or drapes, which, due to their suspension, exhibit folds and thus a modulation of brightness.

[0027] Further embodiments and advantages of the invention are explained below with reference to the figures, in which a true-to-scale and true-to-proportion reproduction has been omitted in order to increase clarity.

[0028] They show: Fig. 1 a schematic representation of an identification card with a security element according to the invention with a combination security feature, Fig. 2 and Fig. 3 illustrate the principle of producing security elements according to the invention, and Fig. Figure 4 shows examples of the outline shape of combination security features of inventive designs.

[0029] The invention will now be explained using the example of securing identification cards. Fig. Figure 1 shows a schematic representation of an identification card 10, such as an ID card, bank card, credit card, or driver's license. In addition to conventional markings, such as a serial number 12 or a portrait 14 of the cardholder, the identification card 10 also has a combination security feature 16 according to the invention, which contains a colored image motif in the form of a national flag, to ensure authenticity.

[0030] As a special feature, the combination security feature 16 shows the flag motif with a flat, two-dimensional appearance under normal illumination with visible light, while under hybrid illumination of visible light and UV light the flag motif surprisingly changes to a three-dimensional appearance, showing the same flag as a moving, particularly waving flag.

[0031] The differing information under normal lighting (daylight) and hybrid lighting (daylight + UV light) creates a surprising effect for the viewer, offering high security and recognition value. A flag element printed as a 2D flag element under daylight becomes, with additional UV stimulation, a spatial perspective 3D image with faithful reproduction of the flag colors. This creates the visual impression of a flag "fluttering" in the wind.

[0032] The Fig. 2 and Fig. 3 illustrate the principle of generating such a combination security feature 16.

[0033] First, Fig. 2(a) providing a two-dimensional (2D) country flag 20 in body color (for example, blue and red) on a white substrate, Fig. 2(b) shows a luminescent color layer 22 or 24 designed according to the invention for producing a three-dimensional (3D) effect with the desired “movement effect” of the later flag visible under UV (two alternative variants are shown), and Fig. Figure 2(c) shows the appearance of 25 under hybrid illumination, i.e. with additional UV excitation (e.g. at 254 nm or 365 nm). Fig. Figure 2(d) shows the intensity I(x) of the luminous profile 28 of the luminescent color layer 22 upon UV excitation along the line 26 of the Fig. 2(b).

[0034] The UV-white fluorescence of the luminescent ink layer 26 causes the flag to shine under hybrid lighting. Elements that are perspectively closer to the viewer glow brighter, while elements of the flag that are farther away glow dimmer. In a further development of the invention, a red-yellow fluorescence coating can be provided, which adds additional color to the 3D appearance. For such a design, at least one additional printing plate is required for background printing processes (offset, Nyloprint), while inkjet printing requires only one additional print head per color.

[0035] Fig. Figure 3 shows schematically the layer structure of a security element according to the invention in cross section, wherein Fig. 3(a) a currently preferred structure and Fig. 3(b) shows an equally advantageous alternative structure.

[0036] With reference to Fig. 3(a), in a first step, a national flag is printed in its body colors 32, 34 visible under daylight, for example, in the colors red (reference numeral 32) and blue (reference numeral 34) on a white substrate 30. Subsequently, in a second step, a luminescent ink layer 36 is printed, which is visually transparent or translucent and fluoresces with the emission color white upon UV excitation. The white fluorescent ink is composed of a mixture of red, green, and blue fluorescent pigments, in particular red, green, and blue fluorescent pigments that exhibit high light and environmental resistance due to a uniform coating material.

[0037] As in Fig. As shown in Figure 3(b), the luminescent ink 36 can be printed not only above, but also below the body color 32, 34. However, due to lower ink consumption, printing above the body color is currently preferred. In all variants, the print motif is advantageously applied using a printing plate in Nyloprint, wet offset printing, or alternatively, using screen printing (water-based or UV-curing).

[0038] The design and production of the luminescent ink layer 36 can be carried out, for example, as follows: To generate the desired flag movement, various parameters are set in an image processing program for 3D effects. For this purpose, the shape (size and aspect ratio, perspective rotation (x, y, z), and distortion of the flag) as well as the desired effect strength determined by the parameters (number of waves, frequency, frequency), the intensity of the wave movement (recognizable in the printed image as brightness contrast), the orientation / direction of the waves, and the distribution on the flag are set from a 3D image processing program.

[0039] To ensure balanced luminosity of the flag's movement, the flag components that are to be perceived by the viewer at different distances are modulated in brightness and initially stored as a grayscale image. This grayscale image is then converted into printable data, for example, as a halftone display, with modulated screens, as an amplitude-modulated or frequency-modulated screen or gravure screen, or even with line thickness modulation or line frequency modulation. For intaglio printing, the grayscale modulation is transferred into the line width and line depth of the grayscale plate or engraving cylinder.

[0040] Through such modulation of the subsequent ink transfer of the luminescent ink in the printing press, different areas of the printed motif appear with varying brightness. The luminescence intensities perceived by the viewer under UV excitation thus depend, for example, on the line / screen / area modulation of the printing plate.

[0041] By varying the resulting intensities, various effects can be generated. These effects create the impression of a moving flag, thus giving the flag a sense of perspective. As mentioned, the parts of the flag that are farther away are advantageously illuminated with lower luminosity, while parts of the flag that are closer to the viewer glow brighter. For areas where the flag appears to be motionless, or for areas that "do not wrinkle," a medium luminosity of white fluorescence is used.

[0042] For example, the area coverage for a flag portion that appears farther away is best between 0-30%, for a medium-distance area between 25-70%, and for an area very close to the viewer between 70-100%. Precise color control can be verified with a fluorescence densiometer to prevent the effect from being overexposed due to excessive color control.

[0043] In a specific embodiment, the printing plate with white fluorescence for the luminescent ink layer 36 can, for example, generate a waving flag suspended on the left. Alternatively, the flag can also be suspended from top to bottom like a standard, or with fixed points on the left and right. A strong brightness contrast in the fluorescence makes the movement appear faster, while shallower effect gradients make it appear slower. The white fluorescent ink is preferably printed as a mixture of a previously mixed color of red, green, and blue pigments. The use of encapsulated pigments with high aging resistance results in consistent print quality.

[0044] The luminescent color layer 36 preferably exhibits white fluorescence for the true-to-color reproduction of a flag printed in body color. However, it is also possible to implement a combination with at least one other fluorescent color, for example, yellow-reddish, for the representation of a flag glowing in the sunset.

[0045] It is particularly advantageous if the entire body color is visible under UV exposure. This can be achieved by applying less fluorescent ink to the darker-looking areas of the surface, thus covering a smaller area, while areas that are perspectively facing the viewer have significantly higher proportions of fluorescent ink. Due to the outshining of closely spaced fluorescence, a narrow area can also remain completely unprinted.

[0046] Additionally, a subtle 3D effect can be created by incorporating further brightness modeling into the brightness modulation of the luminescent color layer, corresponding to a sense of depth in space. For example, a flag can not only exhibit undulating motion but also, in perspective, wave away from the viewer.

[0047] In an advantageous embodiment, a low area coverage of 0-15% of luminescent ink is printed in areas of the flag that are perspectively farther away from the viewer, and a high area coverage of, for example, 60-100% of luminescent ink is printed in areas that are perspectively close to the viewer. It is particularly advantageous if the fluorescence luminosity differs sufficiently between the distant and nearby parts and the fluorescence luminosity gradually increases or decreases. This creates a gradual gradient of brightness in addition to the flag's movement to enhance the effect of depth. For example, a flag flying away from the viewer is provided with a high proportion of fluorescence at its pole attachment, i.e. close to the viewer, while the end of the flag further away from the viewer is provided with a low proportion of fluorescence.The flag visible under UV excitation can also be a shortened or reduced form of a 2D flag in body color.

[0048] In addition to the simple 2D shape of the flat flag as a rectangle shown above for illustration, all other representations of flags and their suspension are also possible within the scope of the invention. Specific examples are cantilever flags, hoist flags, hanging flags, mast flags, standards, banner flags, scrolls, pennants, gonfalons, or double poles. Some examples of the outline shapes of combination security features according to such designs are shown in Fig. 4 a) to f). As can be seen, such outline shapes can greatly enhance the arching effect of a flag, even in its visually visible form. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 1 567 358 B2

[0003]

Claims

[1] Security element for securing security papers, valuable documents and other data carriers with a combination security feature containing a coloured image motif in the form of a flag, where - the combination security feature displays the flag motif with a 2D appearance under normal visible light illumination, and - when illuminated with hybrid visible light and UV light, the flag motif has a 3D appearance, showing a moving, particularly waving, flag, - wherein the combination security feature has a body colour layer with at least two visually visible body colours for generating the 2D appearance of the flag motif and has at least one luminescent colour layer arranged above and / or below the body colour layer, which, when excited with UV light, generates a brightness modulation superimposed on the 2D appearance, which gives the flag motif a 3D appearance as a moving, in particular waving, flag. [2] Security element according to claim 1, characterized by that the luminescent color layer emits white luminescent light when excited by UV. [3] Security element according to claim 1, characterized by that the luminescent color layer emits white luminescent light and additionally reddish or red and / or yellowish or yellow luminescent light upon UV excitation. [4] Security element according to at least one of claims 1 to 3, characterized bythat the luminescent color layer is transparent or translucent in the visible spectral range, in particular that the luminescent color layer is not visually perceptible under normal lighting without UV component. [5] Security element according to at least one of claims 1 to 4, characterized by that the luminescent color layer contains a mixture of red, green and blue emitting luminescent pigments, which have high light and environmental resistance due to a uniform coating material. [6] Security element according to at least one of claims 1 to 5, characterized by that brightness modulation creates a 3D appearance in which elements closer to the viewer appear brighter and elements further away appear dimmer. [7] A method for producing a security element according to any one of claims 1 to 6, wherein on a substrate - a body colour layer with at least two visually visible body colours is applied to create the 2D appearance of the image motif, and - a luminescent color layer is applied above and / or below the body color layer, which, when excited with UV light, creates the brightness modulation superimposed on the 2D appearance. [8] Method according to claim 7, characterized by that the body colors are applied with a number of printing plates of a printing press, and a white-emitting luminescent ink layer is applied with a single further printing plate of the printing press, or that a colored emitting luminescent ink layer is applied with several, in particular two or three further printing plates of a printing press. [9] Method according to claim 7 or 8, characterized bythat the luminescent color of the luminescent color layer is applied with locally different surface densities to generate the brightness modulation. [10] A value document or security document comprising a security element according to any one of claims 1 to 6.

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