Optical variable anti-counterfeiting element

Abstract

The invention relates to an optically variable security element (20) for protecting valuables, the optically variable security element having a relief grid (30) and at least one line grid (40), the relief grid having a plurality of relief elements (36) arranged in a grid shape, the line grid being arranged vertically above or below the relief grid (30) and having a plurality of line elements (42), which extend substantially in the same direction and are modulated in a position-dependent manner, wherein the relief grid (30) and the at least one line grid (40) interact to produce a surface (60) which, for an observer, advances and / or recedes relative to the surface of the security element (20) in the form of a prescribed three-dimensional image pattern by means of the position-dependent modulation of the line elements (42).

Description

Technical Field

[0001] The invention relates to an optically variable anti-counterfeiting element for protecting valuables, and a correspondingly provided data carrier. Background Art

[0002] For protection purposes, data carriers (e.g. value or identification documents, or other valuable items such as trademarked goods and packaging or secondary packaging of valuable branded items) often have security elements, which allow the authenticity of the data carrier to be verified and serve as a protection against illegal copying.

[0003] Security elements with viewing angle-dependent effects play a special role in authenticity protection, since they cannot be reproduced even with the most modern reproduction devices. In this case, the security elements are provided with optically variable elements which present different image effects to the observer when viewed from different viewing angles and, depending on the viewing angle, display different color or brightness effects and / or different graphic patterns. Summary of the invention

[0004] Starting from this point, the object of the invention is to propose a security element of the above-mentioned type which has an attractive appearance and a high degree of resistance to forgery.

[0005] This object is achieved by the features defined in the independent claim. Further developments of the invention are subject matter of the dependent claims.

[0006] The present invention provides an optically variable anti-counterfeiting element for protecting valuables, the optically variable anti-counterfeiting element having:

[0007] a relief grid having a plurality of relief elements arranged in a grid pattern, and

[0008] at least one wire grid arranged vertically above or below the relief grid and having a plurality of wire elements extending substantially in the same direction and modulated in a position-dependent manner,

[0009] The relief grid and the at least one line grid interact to produce for the observer a surface which jumps out and / or back in the form of a defined three-dimensional image pattern relative to the area of ​​the security element by means of a position-dependent modulation of the line elements.

[0010] In the following, for the sake of simplicity, it is often referred to as "line grid" instead of "at least one line grid", but it should be understood that this is only for easier reference and does not mean that the presence of more than one line grid is excluded. The statements made here apply in all cases to at least one line grid in the security element, preferably even to all line grids.

[0011] In a first advantageous variant of the invention,

[0012] The embossed grid is a one-dimensional or two-dimensional embossed grid composed of a plurality of grid elements, and the embossed grid has a first wire mesh size p of less than 500 micrometers in at least one spatial direction, and the grid elements are respectively formed by at least two embossed elements that are directionally reflective in different directions,

[0013] The at least one wire grid has a second wire grid size q in the spatial direction, which second wire grid size q differs minimally from the first wire grid size p, in particular by less than one fifth, and / or the first wire grid size p and / or the second wire grid size q are modulated in a position-dependent manner, and

[0014] The vertical spacing between the relief grid and the wire grid is less than half of the wire grid size p, preferably less than one fifth of the wire grid size p, particularly preferably less than one tenth of the wire grid size p, and in particular less than 15 micrometers.

[0015] The line mesh size p is preferably even less than 400 microns, and in an advantageous embodiment is between 200 microns and 400 microns, and in another advantageous embodiment is between 40 microns and 200 microns. The line grid preferably comprises a plurality of lines whose width is less than half the line mesh size q, in particular between 5 microns and 200 microns. The line width is particularly preferably between 10 microns and 150 microns, in particular between 50 microns and 120 microns. When printing, line widths of more than 8 microns are easily achieved on smooth substrates. The line width can also preferably be selected depending on the number of colors in the line grid, for example, for two colors, the line width is 95 microns, for three colors, the line width is 145 microns. In some printing materials and printing processes, for example in dry offset printing, line widths of 10 to 30 microns are preferred.

[0016] In an advantageous embodiment, at least one line grid is a printed line grid, which is preferably formed at least in a sub-area by a plurality of substantially parallel printed lines with a spacing q. The sub-area can be formed in the form of a pattern, a character or a code. The printed lines can in particular be printed with a semi-transparent ink to ensure that the line grid is partially semi-transparent.

[0017] The relief elements of the relief grid are preferably provided with a reflection-enhancing coating, in particular a metal coating. The coating may be opaque, but may also be translucent, or even largely translucent, in which case it may consist, for example, of a high-refractive-index layer consisting of an HRI (high refractive index) material, such as titanium dioxide or zinc sulfide.

[0018] In an advantageous embodiment, the relief grid is a one-dimensional grid consisting of a plurality of elongated grid elements having the wire mesh size p. Here, the grid elements are preferably each composed of at least two linear relief elements that are directional reflective in different directions. In particular, the grid elements are each formed by a plurality of linear micromirrors, cylindrical Fresnel mirror structures or other preferably achromatic reflective diffractive structures.

[0019] In another equally advantageous embodiment, the relief grid is a two-dimensional grid consisting of a plurality of grid elements having the wire mesh size p in the first spatial direction. The grid elements of the two-dimensional grid are preferably each formed by at least two, preferably at least three, particularly preferably at least four, for example six relief elements, each of which is directionally reflective in a different direction and each of which is formed in particular by a circular or elliptical arrangement of a plurality of micromirrors, a spherical or elliptical Fresnel mirror structure or other preferably achromatic reflective diffractive structures.

[0020] The reflective relief element comprises in particular one or more reflective areas which may be planar or curved, in the former case the relief elements are usually referred to as micromirrors, while in the latter case they usually form Fresnel mirror structure areas. Here, the reflective relief elements of each grid element are preferably arranged and formed so that the grid element produces a reflective behavior of concave or convex curvature. To this end, the individual relief elements may be arranged, for example, adjacent to one another, with the slope of their reflective areas increasing or decreasing, so that in each case they locally reproduce the slope of the concave or convex curvature. In a two-dimensional relief grid, the slope of the reflective area may reproduce the concave or convex curvature in two spatial directions. Alternatively, the slope of the reflective area reproduces the concave or convex curvature only in one spatial direction, while they are irregularly or randomly oriented in another spatial direction.

[0021] The relief grid may occupy the entire area of ​​the security element, but may also be present only in a sub-area of ​​the security element, in particular in the form of graphics, characters or codes.

[0022] According to a preferred improvement of the present invention, the first and / or second wire grid size is modulated in a position-dependent manner so that the position of the grid elements of the embossed grid or the wire grid is given by a phase function φ(x, y), which depends on the position (x, y) of the grid elements in the security element, and whose function value represents the deviation of the position of the grid element in a certain spatial direction from the position of the grid points in a regular grid normalized to the unit interval [0, 1], and the phase function φ(x, y) varies in a position-dependent manner, thereby generating a surface that jumps out and / or jumps back in the form of a prescribed three-dimensional image pattern relative to the area of ​​the security element when observed.

[0023] Further advantageous embodiments of the relief grid and the at least one line grid can be found in document WO 2017 / 220204 A1, the disclosure content of which is incorporated by reference into the present application.

[0024] In a second advantageous variant of the invention, a security element is provided, which comprises an optically variable structure having an embossed structure and a coating,

[0025] The coating comprises an embossed line grid formed by said line grid having a plurality of line elements extending substantially in the same direction and modulated in a position-dependent manner, and preferably also a highly reflective or high-gloss background layer,

[0026] The embossed structure comprises a two-dimensional grid of raised or recessed embossed elements, the embossed structure forming the relief grid, and the embossed elements forming the relief elements,

[0027] The coating is combined with the embossed structure so that substantially every embossed element has at least one line segment of a line within the line grid, and

[0028] At least one of the parameters "position of the line segment on the embossing element", "direction of the line segment on the embossing element" and "form of the line segment" varies in a position-dependent manner on the scale of the optically variable structure, thereby producing a surface that jumps out and / or jumps back in the form of a specified three-dimensional image pattern relative to the area of ​​the security element when observed.

[0029] In the present application, the highly reflective or highly glossy background layer constitutes an additional layer which is applied to the substrate of the security element and is not formed solely by the surface of the substrate itself.

[0030] In the presence of a highly reflective background layer, the layer is preferably formed by a metallic foil, in particular a silver, bronze, brass, gold or metal foil, or by a printed layer with a metallic sheen, in particular a silver printed layer, but other metal foil strips or patches can also be used as background layers. The printed layer with a metallic sheen can be applied in particular by screen printing or flexographic printing processes, or can also be applied using UV-curing offset inks. The effect is particularly evident when using a directional reflective background layer with a high gloss value. Due to the use of a highly reflective background layer, each embossed element is preferably designed as a small concave or convex mirror.

[0031] In the case of a high-gloss background layer, this can be formed, for example, by subsequent surface treatment of the substrate, such as varnishing the substrate during the printing process, or by a high-gloss top layer of the packaging.

[0032] In a preferred embodiment without a background layer, the background contrasting with the grid of embossed lines is formed by the surface of the substrate itself, which background can be produced, for example, during papermaking, for example by smoothing the substrate, and can in particular be formed by calendered paper, coated paper and / or dense paper with a higher filler content (for example a thickness variation of <20% compared to non-densified paper), or by paper with a higher reflectivity due to whitening or an increased titanium dioxide content.

[0033] Calendered paper has a much higher gloss than uncalendered paper. For example, when measured according to DIN EN ISO 2813, DIN 54502, DIN EN ISO 8254-1, EN ISO 8254-2, calendered tissue paper has an average gloss of about 9, while uncalendered tissue paper has an average gloss of about 3.

[0034] In some advantageous embodiments, the embossed element is formed by a raised or recessed circular structure, in particular by a pressed hemispherical structure or hemispherical cap. The bottom area of ​​the embossed element is preferably circular or elliptical. Alternatively, a cone form may also be used, in particular a cone form with many faces, such as an octagonal bottom. In addition, different forms of embossed elements may be present in the embossed structure to further improve the anti-counterfeiting properties.

[0035] The size of the embossing element is preferably in the range of 50 μm to 500 μm, in a first advantageous embodiment, the size is 50 μm to 200 μm, in a second advantageous embodiment, the size is 250 μm to 300 μm. The structure height is preferably less than 200 μm, preferably less than 150 μm, particularly preferably in the range of 20 μm to 110 μm. In a first advantageous embodiment, the structure height is between 20 μm and 30 μm, in a second advantageous embodiment, the structure height is between 50 μm and 70 μm, in a third advantageous embodiment, the structure height is between 90 μm and 110 μm.

[0036] The embossing elements are preferably arranged in a square lattice, a rectangular lattice, a rhombus lattice, a hexagonal lattice or a parallelogram lattice.

[0037] The position of the line segment on the embossed element is preferably given in each case by a phase function φ(x,y), which depends on the position (x,y) of the embossed element in the optically variable pattern and whose function value specifies the relative position of the line segment on the embossed element in a direction perpendicular to the longitudinal dimension of the line segment (normalized to the unit interval [0,1]). In this case, the phase function φ(x,y) varies in a position-dependent manner, so that when observed, a surface is generated which jumps out and / or back in the form of a defined three-dimensional image pattern relative to the security element area.

[0038] The line width of the printed line grid is preferably in the range of 10 μm to 200 μm, preferably in the range of 45 μm to 150 μm, particularly preferably in the range of 80 μm to 150 μm. The printed lines can have a constant line width, or the line width can vary along the longitudinal dimension of the line, in particular widen, narrow or be modulated on one or both sides.

[0039] Further advantageous embodiments of the relief grid and the wire grid can be found in document WO 2016 / 020066 A2, the disclosure content of which is incorporated into the present application by reference.

[0040] In both variants of the invention, two or more line grids are preferably provided which are arranged vertically above or below the relief grid, the lines of the different line grids preferably being applied using different inks. In particular, the lines of the first line grid can be applied using a lighter, preferably translucent ink, while the lines of the second line grid can be applied using a darker, preferably more covering ink. Line grids extending essentially in the same direction each have a preferred direction defined by the direction of the lines, the preferred directions of two or more line grids preferably jointly comprising an angle of 0°, 60°, 90°, 120° or 240°. In the secondary arrangement of the embossed elements, the preferred directions are in particular parallel (0°) or perpendicular (90°) to each other. In the case of a hexagonal honeycomb arrangement, the preferred directions in particular comprise an angle of + / -60° or + / -120°.

[0041] The relief grid and the at least one line grid preferably also cooperate to generate a brightness change and / or a color change of the three-dimensional image pattern when the viewing angle changes by means of a position-dependent modulation of the line elements. The relief grid and the at least one line grid preferably also cooperate to generate an apparent movement of a sub-area of ​​the three-dimensional image pattern or a change in the perspective appearance of the three-dimensional image pattern when the viewing angle changes by means of a position-dependent modulation of the line elements.

[0042] It is particularly advantageous if the security element depicts a combination of a plurality of (especially moving) three-dimensional image patterns in order to draw the viewer's attention more strongly to the movement or to intensify the impression of movement itself, for example by the opposite movement of two three-dimensional image patterns. The combination of a plurality of moving three-dimensional image patterns can be achieved in particular by the above-mentioned technology with a further printed pattern in the region of the relief grid. For example, different line grids can produce the impression of two three-dimensional objects moving relative to each other in different depth planes by their line modulation (for example related to thickness and / or position).

[0043] The combination of multiple (preferably moving) three-dimensional image patterns can also be achieved by a combination of different technologies, for example, in addition to the embossed grid and the line grid that act together, a three-dimensional hologram, such as a three-dimensional hologram with a pumping motion, is also provided on the anti-counterfeiting element. Such three-dimensional image patterns produced by different technologies are preferably associated in meaning with the three-dimensional image patterns produced by the embossed grid and the line grid that act together. The two patterns are particularly preferably related, complementary or mutually explanatory pattern parts of a complete pattern. The patterns can also be associated with each other through their movement patterns, for example, when the viewing angle changes, they show the same movement pattern, or move in the opposite direction to each other.

[0044] In an advantageous development, in order to highlight the motion or the contour of an object, the relief grid of the security element comprises a first and a second sub-area, each of which can be optically perceived as jumping out and / or jumping back, and each of which conveys a tactilely detectable impression. In the first sub-area, the optically perceptible and tactilely detectable impressions of the sub-area match, whereas in the second sub-area, the optically perceptible and tactilely detectable impressions do not match.

[0045] On the one hand, due to the sub-areas that optically jump out and / or jump back, the security element is optically very attractive. On the other hand, since the tactilely detectable impression matches the optically perceptible impression only in the first sub-area and not in the second sub-area, a surprising effect is produced. This tactile change and the resulting tactile perception of the pattern produce a high recognition value and help to easily verify the authenticity of the optically variable element. More details and specific embodiments of the first and second sub-areas can be found in document WO 2012 / 084169 A1, the disclosure content of which is incorporated by reference in the present disclosure.

[0046] The security element is preferably a wide security band, a security strip, a patch or a label for application to security paper, valuable documents or the like, but it can also constitute a security thread, in particular a window security thread or a pendulum security thread, or a tear strip.

[0047] The invention also includes a data carrier with a security element of the type described. The data carrier can be in particular a valuable document, such as a banknote, in particular a paper banknote, a polymer material banknote or a film composite material banknote, a stock, a tax stamp, a warrant, a certificate, a ticket, a check, a high-value admission ticket, but can also be an identification card, such as a credit card, a bank card, a cash card, an authorization card, a personal identification card, or a personalized page of a passport. Finally, the invention also includes an object, in particular a branded item or a (secondary) packaging of a branded item, with a security element of the type described.

[0048] The security element of the present invention can be manufactured in particular according to the methods specified in documents WO 2017 / 220204 A1 and WO 2016 / 020066 A2. In addition, in particular, gravure printing, offset printing, screen printing, foil application, printing on foil and 3D printing of the relief structure can be used as printing or application methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Further exemplary embodiments and advantages of the present invention will be described below with reference to the accompanying drawings, in which, for the sake of clarity, the depicted figures are not drawn to scale.

[0050] In the attached picture:

[0051] Figure 1 is a schematic diagram of a banknote having an optically variable security element of the present invention;

[0052] Figure 2 The basic working principle is schematically shown, with a cross-sectional view showing a sub-area of ​​the security element of the present invention, and the curved area perceived by the viewer when observing;

[0053] Figure 3 yes Figure 2 An enlarged view of one of the mesh elements of the security element in FIG.

[0054] Figure 4 It is available for Figure 2 A top view of a wire grid of a security element in FIG.

[0055] Figure 5 A three-dimensional "snail shell" image pattern is shown. Figure 4 When the line grid in is used, the spatial impression of the image pattern is reconstructed, and two vertical sections of the image pattern in the x and y directions are also shown;

[0056] Figure 6 Schematically shows a top cross-sectional detail of a security element having a two-dimensional relief grid and two differently oriented wire grids;

[0057] Figure 7 It is available for Figure 6 A top view of a wire grid of a security element;

[0058] Figure 8 is a top cross-sectional view of another anti-counterfeiting element of the present invention; and

[0059] Fig. 9 Shown along the IX-IX line through Figure 8 Cross section of a security element in FIG. DETAILED DESCRIPTION

[0060] The invention will now be explained using the example of a security element for banknotes. Figure 1 A schematic diagram of a banknote 10 is shown, which is provided with an optically variable security element 12 according to the invention. When observed, the security element 12 presents a three-dimensional image pattern, which has a surface in the form of a number 14, which jumps out relative to the area of ​​the security element 12 and clearly protrudes, is bent, from the security element or the banknote provided therewith.

[0061] Now refer to Figure 2 and Figure 3 The optically variable security element 20 (eg Figure 1 The basic structure and basic working principle of the anti-counterfeiting element 12) in Figure 2 A cross section of a sub-region of the security element 20 and a curved region 60 perceived by an observer when observing the security element 20 are schematically shown.

[0062] The security element 20 is applied to the banknote substrate 10 via an adhesive layer 22 which is formed on the banknote substrate 10. Figure 3 The security element 20 comprises an embossed lacquer layer 24 in which a relief grid 30 is embossed, to which a metal coating 32, for example consisting of aluminum or silver, is applied before the adhesive layer 22 is applied. In this exemplary embodiment, the relief grid 30 itself consists of a plurality of elongated grid elements 34 of the same type, which are connected to each other in the transverse direction and have their longitudinal axes in the middle. Figure 2 In the schematic diagram of FIG. 3 , the projection plane is extended to produce, for example, a rectangular relief grid consisting of 50×100 grid elements. For the purpose of clarity of the illustration, one of the grid elements 34 is shown in FIG. Figure 3 It is shown in an enlarged cross-sectional view.

[0063] Each grid element 34 consists of a plurality of parallel linear micromirrors 36, the mirror slope of which in each case changes almost continuously from the left edge to the right edge of the grid element in the figure from a first negative slope (from the upper left to the lower right in the figure) to a second positive slope (from the lower left to the upper right). In this way, the micromirrors 36 of each grid element 34 simulate the reflection behavior of a parabolic concave mirror. The term "linear" here refers to the elongated extension of the micromirrors 36 into the projection plane. The reflection area of ​​the micromirrors can be symmetrical and asymmetrical planar areas or also concave and convex curved areas.

[0064] Please refer again Figure 2In the schematic diagram of FIG. 3 , a line grid 40 is arranged vertically above the relief grid 30. The line grid 40 has a plurality of printed lines 42, which extend substantially in the same direction, are modulated in a position-dependent manner, and are printed using a semi-transparent or opaque printing ink. Due to the position-dependent modulation, the printed lines 42 are largely parallel, but not completely parallel (see FIG. 3 ). Figure 4 ), and are therefore said to extend substantially in the same direction. The repetition pattern of the printed lines 42 is different, and a large deviation of the printed lines 42 may also occur in the local area 48.

[0065] Like the longitudinal axis of the grid element 34, Figure 2 The longitudinal axis of the printed line 42 in the projection plane also extends into the projection plane. In addition, the relative lateral position of the printed line 42 relative to the arrangement of the grid elements 34 is not fixed, but varies due to the modulation of the printed line 42 over the entire area of ​​the security element 20. Although each grid element 34 is basically assigned a printed line 42 located above the grid element, the relative lateral position of the grid element 34 and the printed line 42 varies, such as Figure 2 Shown schematically.

[0066] In each case, the printed lines 42 and the micromirrors 36 of the grid element 34 together generate a moiré-magnified topography 50 of a sub-region of the grid element 34. Here, each topography 50 constitutes the contribution of the respective overprinted grid element 34, 42 to the entire curved surface area 60. As a unique feature, the position-dependent modulation of the printed lines 42 is now coordinated with the position of the micromirrors 36 of the relief grid 30, so that in each case the moiré-magnified image 50 locally has the same orientation as the curved surface area 60 to be depicted by the security element. Since the inclination of the micromirrors 36 within the grid element 34 varies quasi-continuously from the left edge to the right edge in each case, by a suitable arrangement of the printed lines 42 relative to the relevant grid element 34, it is possible to generate moiré-magnified images with almost any inclination within the inclination range prescribed by the grid element. Here, the viewing angle of the subsequent moiré image 60 can be visualized by different inclinations of the element 50.

[0067] For a given relief grid 30, the position and the slope of all micromirrors 36 are known. In order to reproduce the desired curved surface area 60, as described in more detail below, the local slope of the area 60 is determined in each case, and the relative position of the printed line 42 in each grid element 34 is selected so that the grid element together with the associated printed line element produces a moiré magnified image of the same slope. For the reflection of the incident light 62, 62', since the geometrical reflection condition "angle of incidence equals angle of reflection" depends in each case only on the local orientation of the reflecting areas 50 and 60, the moiré magnified image 50 captured together in the reflected light 64, 64' can easily imitate the curved surface area 60 to be described. As a result, the security element 20 has an optical impression corresponding to a three-dimensional object whose surface is given by the curved surface area 60.

[0068] exist Figure 2 and Figure 3 In the exemplary embodiment of the embodiment, the effect is shown with a one-dimensional embossed grid composed of elongated grid elements 34, but the principle of the present invention can also be implemented in the same manner using a two-dimensional embossed grid. Figure 2 and Figure 3 An embossed grid 30 having a constant wire screen size is shown, but an embossed grid of variable wire screen size may also be used to achieve the effect.

[0069] In the exemplary embodiment shown, the dimension of the mesh elements 34 in the transverse direction is p=200 micrometers, which dimension simultaneously constitutes the wire mesh dimension p of the relief mesh 30. The dimensions of the mesh elements 34 and the micromirrors 36 in the longitudinal direction (i.e., Figure 2 The penetration dimension into the paper surface in the figure can be several millimeters or even several centimeters, that is, significantly larger than the wire mesh size.

[0070] The wire screens of the relief grid 30 and the wire grid 40 have similar dimensions and differ, for example, by about 5% to 15%. In this exemplary embodiment, the line width of the printed lines 42 is significantly smaller than the average wire screen size of the wire grid 40. Due to the superposition of the relief grid and the wire grid, the observer sees two different reflections in each case, namely white / silver reflections from the uncovered areas of the relief grid 30 and colored reflections from the areas of the printed lines 42 that are covered by the semi-transparent printing ink. Since the printed lines 42 are much narrower than the grid elements 34, the colored reflections are visible over a smaller angle range, while the white / silver reflections are further fanned out.

[0071] The opposite situation is also advantageous, where the line width of the printed line 42 is only slightly smaller than the average line mesh size of the line grid 40. In this case, the white / silver reflection is visible in a smaller angle range, while the colored reflection of the semi-transparent printed line 42 fans out further.

[0072] The line grid 40 particularly advantageously comprises two or more printed lines with different tones, in particular using at least one lighter tones and one darker tones. The lighter color can also be fluorescent or phosphorescent, while red, blue, green or black, or secondary mixed colors, etc. can be used as darker tones. In addition to light and dark contrasts, cold and warm contrasts or mass contrasts can also be produced by different tones. Combinations of light and dark contrasts and cold and warm contrasts are also possible (for example a combination of light blue or cold tones with dark red or warm tones). The printed lines can jointly cover the entire area of ​​the relief structure, thereby producing a color impression for each viewing direction. In this case, at least one printed line type is printed with a transparent, semi-transparent color.

[0073] The combination of an absorbent, covering dark color and a translucent light color has proven to be particularly advantageous. A printed line consisting of a covering color and a translucent color can leave unprinted spaces or can be applied over the entire area. It is particularly advantageous here for the greatest possible difference in chroma, brightness and / or saturation to exist between the two colors, thereby creating the greatest possible contrast.

[0074] Figure 4 Shows the available Figure 2 The security element 20 in the embodiment of FIG. 1 and produces a three-dimensional impression of a snail shell ( Figure 5 ). The line grid comprises a plurality of light-colored printed lines 42, for example printed with a yellow semi-transparent printing ink, and a plurality of dark-colored printed lines 44, for example printed with an opaque blue printing ink. Although both printed lines 42, 44 extend substantially in the same direction 46, it is clearly perceptible that the printed lines have a particularly noticeable modulation at a position 48, where the inclination of the depicted spatial object changes rapidly.

[0075] For the purpose of more clear illustration, Figure 5 A three-dimensional "snail shell" image pattern 70 is shown. Figure 4 When the line grid 40 in FIG. 4 is formed, the spatial impression of the image pattern is reconstructed by the security element 20. The surface function f(x,y) which indicates that the height or z-coordinate of the image pattern 70 in each case is a function of the position (x,y) forms the height fluctuations of the image pattern 70. Figure 5 The vertical cross section 74 in the x direction and the vertical cross section 78 in the y direction are two vertical cross sections taken along the lines 72 and 76 respectively, which are shown in an exemplary manner, wherein the function value f(x,y) (i.e., the height of the image pattern) is plotted in arbitrary units over the position coordinate x (vertical cross section 74 in the x direction) and the position coordinate y (vertical cross section 78 in the y direction). The path of the function can be represented as a high-order polynomial function, for example.

[0076] Based on the surface function f(x,y) of the image pattern to be depicted, the local slopes in the image pattern are determined and then for different slopes a phase change of the line pattern consisting of the print lines 42 to be printed is calculated in each case using a suitable software or programming language (e.g. GDL (GNU Data Language), IDL (Interactive Data Language), Maple (Mathematical Manipulation Language), C++, Visual Script, Modelica, Mathematica, MATLAB (Mathworks), AutoCAD), which phase change in each case indicates the position of the printed line portion relative to the associated grid element 34. The image pattern 70 and the locally different slopes of the surface function f(x,y) lead to different phase changes of the print line portions, which results in the above-mentioned position-dependent modulation of the print lines 42.

[0077] like Figure 4 As shown, the course of the printed lines 42, 44 may deviate significantly locally from a substantially parallel course, the lines may extend obliquely, or even vary discontinuously (region 48), which in extreme cases may result in certain grid elements 34 not being overprinted at all by the printed lines 42 or 44, or not being completely overprinted by the printed lines 42 or 44.

[0078] Use in Figure 2 and Figure 3 By using the technique described in , it is also possible to achieve dynamic line and dot patterns, in which the desired pattern consisting of lines and / or dots appears to float above the plane of the substrate. To this end, the printed line grid can be selected so that adjacent areas reflected in color or associated adjacent moiré magnified images 50 have a reflection angle course that imitates a continuous course. In particular, the course can be selected so that the two eyes of the observer see the colored light reflections at slightly different positions. Due to this stereoscopic effect, the lines or dots appear to float above or below the plane of the substrate and a spatial effect is created.

[0079] The technology also enables a multi-colored three-dimensional depiction of an object which, when viewed from different viewing directions, has different color nuances and / or different relative movement speeds. The color nuances do not necessarily have to correspond to the natural color of the depicted object and, in this way, can draw particularly high attention during verification. It is also possible to systematically speed up or slow down the speed at which the color shadow moves along the depicted object in order to draw more attention to the security element.

[0080] When the viewing angle changes, the depicted spatial object preferably changes brightness or color in different areas. In this case, areas of the three-dimensional object can be visibly moved relative to one another or their perspective appearance can change. In the case of a pumping depiction, a local change in the pumping speed can also be produced.

[0081] The intensity of the line modulation can enhance the spatial impression of the three-dimensional object, i.e. produce a stronger depth effect and a stronger plasticity, or, on the contrary, can also weaken and produce a slight depth effect and a slight plasticity. In this way, a spatial object with a realistic effect can be produced depending on the shape and size. In particular, by combining a plurality of 3D objects in one security element with line modulation (e.g. in relation to thickness and / or position), a movement of two objects relative to each other in different depth planes can be produced. For example, the impression of a ball (first three-dimensional object) can be produced, which in the foreground rolls back and forth in front of a chessboard (second three-dimensional object) depicted in perspective (relative movement of the two three-dimensional objects).

[0082] The depictable spatial objects of the present invention can be simple geometric structures, such as spherical, cubic, rectangular, conical, cylindrical, pyramidal, prismatic objects, but also truncated and distorted elements. In addition, objects of more complex shapes (such as rings, spheres or icosahedrons) are also possible. In addition, animals, plants or objects in daily life can also be depicted, such as Figure 5 A snail shell depicted in.

[0083] The surface function f(x, y) of the image pattern to be depicted is preferably not constant and symmetrical, and it also preferably includes a convex or concave path, or the path is linear but not linear in the xy direction, but only linear in the x or y direction. The surface function is also preferably not periodic in the entire path of the object. Aerial image patterns with varying curvature can be depicted particularly well.

[0084] In addition to one-dimensional relief grids, designs with two-dimensional relief grids and grids of lines with two or more different orientations can also be used, as now referred to. Figure 6 and 7 described.

[0085] first, Figure 6 A top view of a detailed cross-section of a security element 80 with a two-dimensional embossed grid 82 is schematically shown, the embossed grid 92 consisting of a plurality of grid elements 84 connected to each other in two spatial directions. In this exemplary embodiment, the wire mesh size is the same in two spatial directions (hereinafter referred to as the x-direction and the y-direction) and is, for example, 200 microns. Each grid element 84 forms a spherical Fresnel mirror structure, which corresponds to the concave curvature of a spherical divergent Fresnel lens and is, for example, provided with a reflective aluminum metal coating. In the embodiment described, each embossed element 86 is formed by a coated annular area of ​​a divergent Fresnel lens and includes a curved reflective area.

[0086] The relief grid 82 is combined with two printed line grids having different colors and orientations of printed lines 90, 92. The printed lines 90 of the first printed line grid are formed with a dark hue (e.g. dark blue) and, apart from an additional position-dependent modulation, extend substantially in the same y-direction. The printed lines 92 of the second printed line grid are formed with a light hue (e.g. translucent luminous yellow) and, apart from an additional position-dependent modulation, extend substantially in the same x-direction.

[0087] The modulation of the printed lines 90, 92 is Figure 6 There is almost no effect in the detailed cross-section of Figure 7 The entire area of ​​the printed wire grid can be clearly perceived in the top view. Figure 4 Like the line grid 40 in FIG. 1 , these two printed line grids produce Figure 5 The three-dimensional impression of the "snail shell" image pattern 70 in the embossed grid. This line modulation according to two angles of the embossed grid has proven to be particularly advantageous for depicting objects with a spatial effect. Figure 6 and Figure 7 As shown, the two main directions of the printed lines 90, 92 are coordinated with the geometry of the relief structure used and extend perpendicularly to one another in the square lattice geometry of the grid element 84. In this way, the brightness of the visually visible spatial object changes in each case when the security element is tilted relative to the two main directions.

[0088] In a hexagonal lattice geometry, for example, three wire grids can be used, the three main directions of which in each case comprise an angle of 60° or 120° with one another.

[0089] Figure 8 and Fig. 9 Another exemplary embodiment of the invention is shown, which differs from the exemplary embodiments described so far in the type of relief grid. Figure 8 shows a top cross-sectional view of the security element 100, Fig. 9 Shown along Figure 8 The IX-IX line in passes through the cross section of the security element.

[0090] The security element 100 includes an optically variable structure formed by a combination of an embossed structure 102 and a coating 104. The coating 104 includes a highly reflective background layer 106, such as a continuous reflective silver layer with high gloss, which is printed on a banknote substrate 108 of the security element 100, for example, by screen printing. The silver background layer 106 provides the security element 100 with a primarily metallic glossy appearance. In addition, additional functional value of the security element 100, such as contour shapes, patterns or characters, can be produced by systematically interrupting the silver background layer. In another embodiment, there may also be no silver layer and a high gloss layer may be used instead. Examples of suitable high gloss layers include coated substrates, such as glossy paper or varnished paper. For example, the high gloss layer may also be formed by a high gloss adhesion-promoting layer applied to the surface of a substrate having a pigment or filler (e.g., rutile-titanium dioxide) in screen printing.

[0091] In another embodiment not shown here, the background layer can also be completely omitted. In this case, a lightweight, high-gloss substrate can be advantageously used, which consists, for example, of coated and / or calendered paper (especially with a higher filler content) or of paper with a higher white content (especially a higher titanium dioxide content).

[0092] Calendered papers, especially calendered papers with a higher proportion of fillers such as titanium dioxide, have a much higher gloss than non-calendered papers. For example, calendered tissue papers have an average gloss of about 9, while uncalendered tissue papers typically have an average gloss of about 3, when measured in accordance with DIN EN ISO 2813, DIN 54502, DIN EN ISO 8254-1, EN ISO 8254-2. For example, one manufacturer of suitable gloss meters is BYK Gardner (device name: micro-gloss).

[0093] If the security element 100 is integrated into a data carrier, such as a banknote, the substrate 108 can also be the substrate of the value document itself.

[0094] A colored (eg, gold) line grid 110 is embossed on the background layer 106. The line grid 110 consists of a plurality of printed lines 112 which extend substantially in the same direction and are modulated in a position-dependent manner. The line grid 110 can be, for example, Figure 4 Moreover, a plurality of line grids may also be arranged at a certain angle to each other, for example Figure 7 The line grid in .

[0095] The coating 104 formed by the background layer 106 and the wire grid 110 is combined with an embossed structure 102 consisting of a two-dimensional square grid of embossed elements 114, which in this exemplary embodiment are formed by pressed hemispherical protrusions. The protrusions 114 have, for example, a root diameter d of 250 micrometers. P and 75 microns height h p .from Figure 8 It can be seen that the wire mesh size of the imprint element grid is larger than the root diameter of the imprint element. The wire mesh size of the imprint element grid and the average wire mesh size of the wire grid are substantially matched, for example, 300 microns.

[0096] Since the wire mesh size is matched, the coating 104 and the embossed structure 102 act together, on the one hand, each protrusion 114 acts as a small convex mirror due to the reflection effect of the background layer 106, and on the other hand, a line segment 116 of a line 112 of the wire grid 110 is present on substantially each protrusion 114. Due to the modulation of the line 112, it may occasionally happen that there are no line segments on some protrusions of the embossed structure.

[0097] Since the position of the line segment 116 on the embossing element 114 has a characteristic of being position-dependently variable, the line segment 116 is located in regions of different local slopes of the embossing element. Fig. 9 It can be seen from the cross section that the slope of the mirror projection 114 changes continuously from the left edge to the right edge, so that by suitable arrangement of the line segments 116 relative to the relevant embossing elements 114, the local reflection behavior of the curved surface area to be portrayed in each case can be simulated.

[0098] Thus, the security element 100 can be formed to have an optical impression corresponding to a three-dimensional object whose surface is given by the desired curved surface area.

[0099] Reference numerals

[0100] 10 Banknotes

[0101] 12 Anti-counterfeiting elements

[0102] 14 Numerical numbers

[0103] 20 Anti-counterfeiting elements

[0104] 22 Adhesive layer

[0105] 24 Embossed paint layer

[0106] 30 Embossed Mesh

[0107] 32 Metal cladding

[0108] 34 Grid Elements

[0109] 36 Microscope

[0110] 40 Line Grid

[0111] 42,44 Printing Line

[0112] 46 Direction of printed lines

[0113] 48 High modulation position

[0114] 50 Moiré magnification morphology

[0115] 60 Depicted curved area

[0116] 62,62' Incident light

[0117] 64,64' Reflected Light

[0118] 70 3D image patterns

[0119] 72 Cutting Line

[0120] 74 Vertical section in x direction

[0121] 76 Cutting Line

[0122] 78 Vertical section in the y direction

[0123] 80 Anti-counterfeiting elements

[0124] 82 2D embossed mesh

[0125] 84 Grid Elements

[0126] 90,92 Printing Lines

[0127] 100 Anti-counterfeiting elements

[0128] 102 Imprinted structure

[0129] 104 Coating

[0130] 106 Background Layer

[0131] 108 Substrate

[0132] 110 Line Grid

[0133] 112 Printing Line

[0134] 114 Embossed element in raised form

[0135] 116 line segments.

Claims

1. An optically variable security element for protecting valuables and for depicting a curved area, comprising: A relief grid having a plurality of relief elements arranged in a grid pattern, wherein the relief grid is a one-dimensional or two-dimensional relief grid consisting of a plurality of grid elements, and wherein the grid elements are respectively formed by at least two relief elements that are directionally reflective in different directions, and at least one wire grid arranged vertically above or below the relief grid and having a plurality of wire elements extending substantially in the same direction and modulated in a position-dependent manner, The relief grid and the at least one line grid act together to produce for the observer, by means of a position-dependent modulation of the line elements, a surface which jumps out and / or back in the form of a defined three-dimensional image pattern with a varying curvature relative to the area of ​​the security element and is given by the curved surface area to be depicted, in, the position-dependent modulation of the line elements is coordinated with the position of the relief elements of the relief grid so that the moiré-magnified image of a sub-region of the grid element has in each case locally the same orientation as the surface region, wherein the relief grid and the line grid act together to generate an apparent movement of a sub-region of the three-dimensional image pattern or a change in the perspective appearance of the three-dimensional image pattern as the viewing angle changes by means of a position-dependent modulation of the line elements, Wherein, the embossed grid is a one-dimensional grid composed of a plurality of elongated grid elements, and each grid element is formed by a plurality of linear micromirrors or a cylindrical Fresnel mirror structure; or wherein the embossed grid is a two-dimensional grid composed of a plurality of grid elements, and each grid element is formed by a circular or elliptical arrangement of a plurality of identical and / or different micromirrors or a spherical or elliptical Fresnel reflector structure.

2. The optically variable anti-counterfeiting element according to claim 1, characterized in that: The relief grid has a first wire mesh size p of less than 500 micrometers in at least one spatial direction, The at least one wire grid has a second wire grid size q in the spatial direction, which second wire grid size q differs minimally from the first wire grid size p, and / or the first wire grid size p and / or the second wire grid size q are modulated in a position-dependent manner, and The vertical spacing between the relief grid and the wire grid is less than half of the wire mesh size p.

3. The optically variable anti-counterfeiting element according to claim 2, characterized in that: The second web size q differs from the first web size p by less than one fifth.

4. The optically variable anti-counterfeiting element according to claim 2, characterized in that: The vertical spacing between the relief grid and the wire grid is less than one fifth of the wire mesh size p.

5. The optically variable anti-counterfeiting element according to claim 2, characterized in that: The vertical spacing between the relief grid and the wire grid is less than one tenth of the wire mesh size p.

6. The optically variable anti-counterfeiting element according to claim 2, characterized in that: The vertical spacing between the relief grid and the wire grid is 15 microns smaller than the wire mesh size p.

7. The optically variable anti-counterfeiting element according to claim 2, characterized in that: Each grid element is formed by at least two linear relief elements that are directionally reflective in different directions.

8. The optically variable anti-counterfeiting element according to claim 2, characterized in that: The two-dimensional grid has the wire mesh size p in a first spatial direction and wherein each grid element is formed by at least two relief elements that reflect directionally in different directions.

9. The optically variable anti-counterfeiting element according to claim 8, characterized in that: Each grid element is formed by at least three relief elements that are directionally reflective in different directions.

10. The optically variable anti-counterfeiting element according to claim 8, characterized in that: Each grid element is formed by at least four relief elements that are directionally reflective in different directions.

11. The optically variable anti-counterfeiting element according to claim 8, characterized in that: Each grid element is formed by at least six relief elements that are directionally reflective in different directions.

12. The optically variable security element according to any one of claims 2 to 11, characterized in that: The reflective relief elements of each grid element are arranged and formed such that the grid element produces a reflective behavior with a concave or convex curvature.

13. The optically variable anti-counterfeiting element according to claim 8, characterized in that: The reflective relief element comprises one or more reflective areas, the reflective relief elements of each grid element being arranged and formed such that the slopes of the reflective areas reproduce a concave or convex curvature only in one spatial direction, while they are irregularly or randomly oriented in another spatial direction.

14. The optically variable security element according to any one of claims 2 to 11, characterized in that: The relief grid is present only in a sub-area of ​​the security element.

15. The optically variable anti-counterfeiting element according to claim 14, characterized in that: The embossed grid is formed in the form of graphics, characters or codes.

16. The optically variable security element according to any one of claims 2 to 11, characterized in that: The first and / or second wire grid size is modulated in a position-dependent manner so that the position of the grid elements of the embossed grid or the wire grid is given by a phase function φ(x, y), which depends on the position (x, y) of the grid elements in the security element, and whose function value represents the deviation of the position of the grid element from the position of the grid points in a regular grid normalized to the unit interval [0, 1], and the phase function φ(x, y) varies in a position-dependent manner, thereby producing a surface that jumps out and / or jumps back in the form of a prescribed three-dimensional image pattern relative to the area of ​​the security element when observed.

17. The optically variable security element according to any one of claims 1 to 11, characterized in that: The security element depicts a combination of a plurality of three-dimensional image patterns, wherein the combination of the plurality of three-dimensional image patterns is achieved by a combination of different technologies.

18. The optically variable anti-counterfeiting element according to claim 17, characterized in that: The security element depicts a combination of a plurality of moving three-dimensional image patterns, wherein, in addition to the interacting relief grid and line grid, a three-dimensional hologram is also provided on the security element.

19. The optically variable anti-counterfeiting element according to claim 1, characterized in that: Two or more line grids are provided arranged vertically above or below the relief grid, the lines of different line grids being applied using different inks.

20. The optically variable anti-counterfeiting element according to claim 1, characterized in that: The line width of the line element varies along the longitudinal dimension of the line element.

21. The optically variable anti-counterfeiting element according to claim 1, characterized in that: The relief grid and the line grid work together to produce a brightness change or a color change of a three-dimensional image pattern through position-dependent modulation of the line elements when the viewing angle changes.

22. The optically variable anti-counterfeiting element according to claim 1, characterized in that: The embossed grid includes first and second sub-areas, each of which can be optically perceived as jumping out and / or jumping back, and each of the two sub-areas conveys a tactilely detectable impression, the optically perceptible impression of the first sub-area matches the tactilely detectable impression, and the optically perceptible impression of the second sub-area does not match the tactilely detectable impression.

23. An optically variable anti-counterfeiting element for protecting valuables, comprising: a relief grid having a plurality of relief elements arranged in a grid pattern, and at least one wire grid arranged vertically above or below the relief grid and having a plurality of wire elements extending substantially in the same direction and modulated in a position-dependent manner, The relief grid and the at least one line grid act together to produce for the observer, by means of a position-dependent modulation of the line elements, a surface which jumps out and / or back in the form of a defined three-dimensional image pattern with a varying curvature relative to the area of ​​the security element and is given by the curved surface area to be depicted, in, the position-dependent modulation of the line elements is coordinated with the position of the relief elements of the relief grid so that the moiré-magnified image of a sub-region of the grid element has in each case locally the same orientation as the surface region, The anti-counterfeiting element comprises an optically variable structure having an embossed structure and a coating, said coating comprises an embossed wire grid formed by said wire grid having a plurality of wire elements extending substantially in the same direction and being modulated in a position-dependent manner, The embossed structure comprises a two-dimensional grid of raised or recessed embossed elements, the embossed structure forming the relief grid, and the embossed elements forming the relief elements, The coating is combined with the embossed structure so that substantially every embossed element has at least one line segment of a line within the line grid, and at least one of the parameters "position of the line segment on the embossed element", "direction of the line segment on the embossed element" and "form of the line segment" varies in a position-dependent manner on the scale of the optically variable structure, so that when observed, a surface is generated which jumps out and / or jumps back in the form of a defined three-dimensional image pattern relative to the area of ​​the security element, wherein the relief grid and the line grid act together to generate an apparent movement of a sub-region of the three-dimensional image pattern or a change in the perspective appearance of the three-dimensional image pattern as the viewing angle changes by means of a position-dependent modulation of the line elements, The embossing element is formed by a convex or concave circular structure.

24. The optically variable anti-counterfeiting element according to claim 23, characterized in that: The coating may also include a highly reflective or high gloss background layer.

25. The optically variable anti-counterfeiting element according to claim 24, characterized in that: In case a highly reflective background layer is present, it is formed by a metallic foil or by a printed layer having a metallic sheen.

26. The optically variable anti-counterfeiting element according to claim 25, characterized in that: The metallic luster foil comprises silver, bronze, brass or gold foil, the printed layer with metallic luster comprises a silver printed layer, and each embossed element acts as a small concave mirror or convex mirror through a highly reflective background layer.

27. The optically variable anti-counterfeiting element according to claim 23, characterized in that: The background, which contrasts with the grid of embossed lines, is formed by the surface of the substrate itself.

28. The optically variable anti-counterfeiting element according to claim 27, characterized in that: The background, which contrasts with the grid of embossed lines, is formed by calendered paper, coated paper and / or high-density paper having a higher filler content.

29. The optically variable anti-counterfeiting element according to claim 23, characterized in that: The embossing element is formed by a compressed hemispherical structure or a cap-shaped structure having a circular or oval bottom area.

30. The optically variable security element according to any one of claims 23 to 28, characterized in that: The position of the line segment on the embossed element is given in each case by a phase function φ(x,y), which depends on the position (x,y) of the embossed element in the optically variable structure and whose function value indicates the relative position of the line segment on the embossed element normalized to the unit interval [0,1] in a direction perpendicular to the longitudinal dimension of the line segment, and the phase function φ(x,y) varies in a position-dependent manner, thereby producing a surface that jumps out and / or jumps back in the form of a specified three-dimensional image pattern relative to the area of ​​the security element when observed.

31. The optically variable anti-counterfeiting element according to claim 23, characterized in that: Two or more line grids are provided arranged vertically above or below the relief grid, the lines of different line grids being applied using different inks.

32. The optically variable anti-counterfeiting element according to claim 31, characterized in that: The lines of the different line grids are applied using semi-transparent ink and opaque ink.

33. The optically variable anti-counterfeiting element according to claim 31, characterized in that: The wire grids extending substantially in the same direction each have a dominant direction defined by the direction of the wires, the dominant directions of two or more wire grids together comprising an angle of 0°, 60°, 90°, 120° or 240°.

34. The optically variable anti-counterfeiting element according to claim 23, characterized in that: The line width of the line element varies along the longitudinal dimension of the line element.

35. The optically variable anti-counterfeiting element according to claim 34, characterized in that: The line width of the line element increases, decreases or is modulated on one side or both sides along the longitudinal dimension of the line element.

36. The optically variable anti-counterfeiting element according to claim 23, characterized in that: The relief grid and the line grid work together to produce a brightness change or a color change of a three-dimensional image pattern through position-dependent modulation of the line elements when the viewing angle changes.

37. The optically variable anti-counterfeiting element according to claim 23, characterized in that: The embossed grid includes first and second sub-areas, each of which can be optically perceived as jumping out and / or jumping back, and each of the two sub-areas conveys a tactilely detectable impression, the optically perceptible impression of the first sub-area matches the tactilely detectable impression, and the optically perceptible impression of the second sub-area does not match the tactilely detectable impression.

38. A data carrier or an object having an optically variable security element according to any one of claims 1 to 37.

39. A data carrier or object as claimed in claim 38, comprising a branded item, packaging or secondary packaging of a branded item.

Images