EP3475096B1 - Optically variable security element - Google Patents

Description

The invention relates to an optically variable security element for protecting valuables. The invention also relates to a method for producing such a security element and a correspondingly equipped data carrier.

Data carriers, such as value or ID documents, or other valuables, such as branded items, are often provided with security elements for protection, which allow the authenticity of the data carrier to be checked and which also serve as protection against unauthorized reproduction.

Security elements with effects that depend on the viewing angle play a special role in securing authenticity, as these cannot be reproduced even with the most modern copiers. The security elements are equipped with optically variable elements that give the viewer a different image impression from different viewing angles and, for example, show a different color or brightness impression and/or a different graphic motif depending on the viewing angle.

Colored and dynamic human characteristics that are easy to verify are of particular interest in security printing as well as in packaging printing. At present, such features are mainly realized by holograms and hologram-like designs, which, however, place considerable technological demands on the manufacturing process and therefore cannot be used economically for all applications.

From the pamphlet WO 2009/000530 A2 discloses a security element with a micro-optical Moiré magnification arrangement for displaying a three-dimensional Moiré image that contains image components in at least two Moiré image planes that are spaced apart in a direction perpendicular to the Moiré magnification arrangement. The moiré magnification arrangement comprises a motif image containing two or more lattice cell arrangements with different lattice periods and/or different lattice orientations, each associated with a moire image plane and containing micromotif image components for representing the image component of the associated moire image plane, and a focusing element grid arranged at a distance from the motif image for moiré-magnified viewing of the motif image, which grid contains an arrangement of a plurality of grid cells, each with a microfocusing element. When the security element is tilted, the enlarged, three-dimensional moiré image moves in a moire movement direction that differs from the tilting direction for almost all tilting directions.

Also in print WO 2007/076952 A2 describes a security element with a micro-optical moiré magnification arrangement, with a motif image that consists of an arrangement of a plurality of micromotif elements, and an arrangement of a plurality of microfocusing elements for moiré-enlarged viewing of the micromotif elements of the motif image.

Proceeding from this, the invention is based on the object of specifying an optically variable security element of the type mentioned at the outset, which avoids the disadvantages of the prior art. In particular, a security element that is simple and inexpensive to produce is to be provided, which shows visually appealing movement effects when tilted and which ideally also has a small thickness and is therefore well suited for application to banknotes and other documents of value.

This object is solved by the features of the independent claims. Developments of the invention are the subject matter of the dependent claims.

• einem ein- oder zweidimensionalen Reliefraster aus einer Mehrzahl von Rasterelementen, welches in zumindest einer Raumrichtung eine erste Rasterweite p unterhalb von 500 µm aufweist, und bei dem die Rasterelemente jeweils aus zumindest zwei, in unterschiedliche Richtungen gerichtet reflektierenden Reliefelementen gebildet sind, und
• mit zumindest einem Punkt- und/oder Linienraster, das vertikal über oder unter dem Reliefraster angeordnet ist, und in der genannten Raumrichtung eine zweite Rasterweite q aufweist, wobei sich die zweite Rasterweite q von der ersten Rasterweite p um weniger als ein Fünftel unterscheidet, und/oder die erste Rasterweite p und/ oder die zweite Rasterweite q ortsabhängig moduliert sind, so dass durch das Zusammenwirken von Reliefraster und Linienraster beim Kippen des Sicherheitselements ein Bewegungseffekt entsteht,
• und wobei der vertikale Abstand von Reliefraster und Punkt- und/oder Linienraster weniger als die halbe Rasterweite p beträgt.

The invention contains an optically variable security element for protecting valuables

• a one- or two-dimensional relief raster consisting of a plurality of raster elements, which has a first raster width p below 500 µm in at least one spatial direction, and in which the raster elements are each formed from at least two relief elements reflecting in different directions, and
• with at least one point and/or line grid, which is arranged vertically above or below the relief grid, and has a second grid width q in said spatial direction, the second grid width q differing from the first grid width p by less than one-fifth, and / or the first screen width p and / or the second screen width q are modulated depending on location, so that through the interaction of relief grid and line grid when the security element is tilted, a movement effect is created,
• and wherein the vertical distance between the relief screen and the point and/or line screen is less than half the screen width p.

According to current understanding, the movement effect is created by a moiré effect between two screens of similar screen width, in this case the relief screen and the point and/or line screen. The raster widths of the relief raster and the point and/or line raster differ by less than one-fifth. Alternatively or additionally, the grid width of one of the two grids or even both grids is suitably modulated as a function of location. In the latter case, the raster width of the point and/or line raster can in principle also be the same as the raster width of the relief raster, since the Moiré effect is already caused by the location-dependent modulation.

In the following, for the sake of simplicity, only "the point and/or line grid" is often addressed instead of "the at least one point and/or line grid", but it goes without saying that this does not mean that there is more than one point and/or line grid should be excluded. The statements made then apply to at least one, preferably even to all, point and/or line grids of the security element. In particular, in the case of several point and / or line screens, the screen widths of the point and / or line screens are preferably all selected so that they differ from the first screen width p by less than one-fifth and / or the first screen width p and / or the second grid width q are modulated in a location-dependent manner in such a way that a movement effect is created by the interaction of the relief grid and the respective point and/or line grid when the security element is tilted. If the relief screen is a two-dimensional relief screen which, in addition to the first screen width p, has a further screen width p' in a second spatial direction, then in the case of line screens, a second or further line screen can also have a screen width that differs from the first Screen width p differs only slightly from the further screen width p', in particular by less than one-fifth, and/or is modulated in such a location-dependent manner that the interaction of the relief screen and the respective line screen causes a movement effect when the security element is tilted. In the case of a two-dimensional dot screen which, in addition to the first screen width q, has a further screen width q' in a second spatial direction, the further screen width q' can differ only slightly from the further screen width p' and/or one or both of the screen widths p' , q' can be modulated depending on the location in such a way that a movement effect is produced by the interaction of the relief grid and the grid of dots when the security element is tilted.

In an advantageous embodiment, at least one of the point and/or line grids is designed as a line grid. In this case, even all point and/or line grids are preferably designed as line grids.

The screen width p is advantageously even smaller than 400 μm and is between 200 μm and 400 μm in one advantageous embodiment, and between 60 μm and 200 μm in another advantageous embodiment. The second screen width q differs from the first screen width p only slightly, in particular by less than one fifth or even by less than one Tenths, especially by less than 15 microns. However, for other designs, for example for use in branded items or in packaging printing, the screen width p can also be greater than 400 μm.

In the case of a line screen, the line screen advantageously has a large number of lines, the width of which is preferably between 5 μm and 200 μm, but is in any case smaller than half the screen width q. The line width is particularly preferably between 45 μm and 150 μm and in particular between 50 μm and 120 μm.

The lines can be unmodulated, ie have a constant line width along their length. However, the line width can also change along the longitudinal extent of the lines, in particular increase or decrease, or can be modulated on one or two sides. The lines of the line grid can be materially positive, for example as printed or metallized lines, but they can also be material-free as a negative, i.e. as a gap in a surrounding material area, for example as linear gaps in a printed image or a metal coating. In the case of positive lines, the specified line widths refer to the widths of the material areas and in the case of negative lines to the widths of the material-free areas left out. Additional information can be encoded in the security element by changing the line width along the longitudinal extent of the lines. The movement effect can be intensified by this additional information or even remain static, for example in the case of a recess in the underground.

The lines of a line grid can also contain recessed areas, which are formed in particular in the form of patterns, characters or a code are. The recessed areas are preferably arranged in the form of a grid, which has a grid width in one spatial direction that differs little or not at all from a grid width of the relief grid, in particular by less than one fifth.

In the case of a point raster, the raster elements (points) of the point raster can have any shape and in particular can be designed in the form of patterns, characters or a code. In particular, the raster elements themselves can consist of a plurality of points, for example of different colors, or can be broken down into such points.

In an advantageous embodiment, at least one line grid is a printed line grid, which is preferably formed at least in a partial area from a multiplicity of essentially parallel printed lines with a spacing q. The partial area can be in the form of a pattern, character or code. However, the print line grid can also be formed entirely from parallel print lines. The printed lines can in particular be printed with a translucent color in order to ensure that the line grid is partially transparent to light.

The printed line screen or screens are advantageously separated from the relief screen by a spacer layer, the spacer layer preferably containing an embossing lacquer layer into which the relief elements of the relief screen are embossed. The embossing lacquer layer is expediently transparently clear or transparently colored. The spacer layer can in particular be formed only by the embossing lacquer layer, or can also be formed by a film with an embossing lacquer layer present thereon.

The relief elements of the relief grid are advantageously provided with a reflection-increasing coating, in particular a metallization. The color impression of the metallization is preferably essentially metallic silver, such as with a metallization made of aluminum or silver, but the use of colored metals, such as copper or gold, can also be considered. The coating can be opaque, but also semi-transparent or even largely translucent, and then consist, for example, of a high-index layer of HRI (High Refractive Index) materials, for example TiO ₂ or ZnS. A dark background is an advantage when using HRI materials.

In an advantageous embodiment, it is provided that at least one point or line screen is formed by a reflection-increasing coating of the relief elements of the relief screen that is present in the form of a point or line screen. In the case of a line raster, the line raster then contains alternately coated and uncoated lines, ie, in the case of metallization, metallized and demetallized lines. The uncoated line areas reveal layers or information lying under the relief grid and therefore allow an intelligent combination of the relief grid with a background design. Such a background design can be formed, for example, by an offset printing layer or a nyloprint layer present on the substrate.

The relief grid is advantageously combined with a background layer lying under the reflection-increasing coating, in particular a color layer covering the entire surface. The background layer appears in the uncoated dot and/or line areas and thus provides a dot and/or line raster which is perfectly matched to the relief raster and has a coloring defined by the background layer. The underground layer can also be multicolored and represent a pattern or other motif and can be printed or applied by any other method. Furthermore, as an alternative or in addition to the background layer, the relief grid can be combined with a colored transparent or translucent layer overlying the reflection-increasing coating, which appears specifically in the uncoated point and/or line areas. The coloring of the grid of points and/or lines produced in this way in register with the relief grid is defined by the coloring of the transparent or translucent layer. In a preferred embodiment, the colored transparent layer is formed by the embossing lacquer layer. A colored embossing varnish can determine the color of the security element or change it in the area of the embossing varnish. Spot coating with two differently colored or colorless embossing varnishes is also possible. For example, the embossing lacquer can be colored yellow in a first partial area and be colorless in a second partial area. If such an embossing lacquer layer is combined with a blue background, a first greenish sub-area (combination of blue+yellow) and a second blue sub-area (combination of blue+colorless) result in the security element in perfect register.

The small vertical distance between the relief grid and the point and/or line grid represents a significant advantage of the security elements according to the invention for example in the case of focusing lens or mirror arrangements, no minimum distance between the two grids can be maintained. The vertical distance between the relief screen and the point or line screen is therefore advantageously less than one-fifth, in particular even less than one-tenth of the screen width p, and is mostly below 20 µm, sometimes even below 10 µm or even below 5 µm. In the extreme case, the vertical distance can even be equal to zero, if namely the point and/or line grid is formed in the reflection-increasing coating of the relief grid and is therefore arranged directly and without a gap on this.

In an advantageous variant of the invention, the relief screen is a one-dimensional screen composed of a plurality of elongated screen elements, which has the mentioned screen width p. The raster elements are advantageously each formed from at least two line-like relief elements reflecting in different directions. In particular, the raster elements are each formed from a multiplicity of linear micromirrors, from a cylindrical Fresnel mirror structure or from other, preferably achromatically reflecting, diffractive structures.

In another, likewise advantageous variant of the invention, the relief screen is a two-dimensional screen made up of a plurality of screen elements, which has the mentioned screen width p in a first spatial direction. As a two-dimensional raster, the relief raster has, in addition to the first raster width p, a further raster width p′ in a second spatial direction, which is not mandatory but also advantageously below 500 μm, in particular below 400 μm. In an advantageous embodiment, the first grid width p and the further grid width p′ are the same, so that the grid elements can be square or spherical. However, the first screen width p and the further screen width p′ can also differ, preferably by a factor of between 1.5 and 5, and form a screen with rectangular or elliptical screen elements.

The raster elements of a two-dimensional raster are advantageously each formed from at least two, preferably at least three, particularly preferably at least four, each reflecting relief elements directed in different directions and are in particular each made of a circular or elliptical arrangement of a large number of micromirrors, of a spherical or elliptical Fresnel -Mirror structure or formed from other, preferably achromatic reflecting diffractive structures. The relief elements can in particular be arranged in a grid-like manner within a grid element itself, for example n*m relief elements (n, m integers ≧2) in the form of an n×m grid.

In an advantageous development, the grid elements are arranged with an outline in the form of a motif and spaced apart from one another. The grid elements can in particular be designed with a simple geometric outline, for example a circle, rectangle, ellipse, star and the like, or can also form a more complex motif, such as a coat of arms, a cloud structure, a flower or the like.

Advantageously, the grid elements are each formed from a large number of relief elements that reflect in different directions, in particular in the case of a one-dimensional grid of at least 10 line-like relief elements that reflect in different directions, and in the case of a two-dimensional grid of at least 10 x 10, directed in different directions reflective relief elements.

In particular, the reflective elements in relief have one or more reflective surfaces, which can be flat or curved, the elements in relief typically being referred to as micromirrors in the former case, while they typically form a zone in the latter case form a Fresnel mirror structure. The reflective relief elements of each raster element are advantageously arranged and designed in such a way that the raster element produces the reflection behavior of a concave or convex curvature. For this purpose, the individual relief elements can be arranged next to one another, for example with an increasing or decreasing slope of their reflection surface(s), so that they each locally simulate the slope of a concave or convex curvature. In the case of two-dimensional relief grids, the slopes of the reflection surfaces in two spatial directions can simulate a concave or convex curvature. Alternatively, the gradients of the reflection surfaces only simulate a concave or convex curvature in one spatial direction, while they are randomly or randomly oriented in the other spatial direction.

The raster elements of the relief raster can all be of the same design, that is to say they can all be formed with the same arrangement of relief elements. Alternatively, the relief raster can also contain two or more different raster elements, which preferably each produce different movement effects when the security element is tilted. For example, the relief raster can contain first raster elements that generate the reflection behavior of a concave curvature and second raster elements that generate the reflection behavior of a convex curvature. The lines generated by the first and second raster elements then move in opposite directions due to the different curvature when the security element is tilted. As a result, the lines of a moiré line pattern generated in interaction with a point and/or line screen also migrate in opposite directions.

The relief grid can take up the entire area of the security element, but it can also only be present in partial areas of the security element, in particular in the form of patterns, characters or a code.

The grid of points and/or lines advantageously comprises a large number of parallel lines which run essentially perpendicularly to the first spatial direction mentioned. The lines of further line grids can also run essentially perpendicularly, but also essentially parallel to the first spatial direction.

As already mentioned above, two or more point and/or line grids arranged vertically above or below the relief grid can also be provided in the security element. The directions given above and below refer to the direction towards the viewer. An element that is closer to the observer is "above" an element that is further away, and the latter is correspondingly "below" the former element. If several point and/or line grids are provided, at least one point and/or line grid is advantageously arranged above the relief grid. The several point and/or line grids can also all be arranged above the relief grid and are in particular registered to one another. Several point and/or line screens are advantageously available in different, in particular contrasting, colors. They can be in almost congruent areas, in partially overlapping areas or in separate areas.

In another advantageous embodiment, at least one grid of points and/or lines is arranged above and at least one grid of points and/or lines is arranged below the relief grid. This allows two-sided security elements to be implemented, viewed from two opposite sides can be and each show a movement effect. Such two-sided security elements can be introduced into a data carrier, for example in the form of a pendulum security thread, or can be arranged over a window area or a hole in a data carrier.

In advantageous configurations, either the first grid width p is fixed and the second grid width q is modulated as a function of location, or the second grid width q is fixed and the first grid width p is modulated as a function of location. It can be provided in particular that the first grid width p varies locally with a fixed second grid width q. The raster elements themselves are advantageously all of the same design. A similar effect can be achieved if the first screen width p is fixed, but the curvature or the gradient of the relief elements forming the screen elements varies locally.

A location-dependent modulation of the relief grid can also be produced by using elliptical or circular micromirror arrangements or cylindrical, elliptical or circular Fresnel mirror structures with a location-dependent shift in the center of gravity. A controlled effect modulation can also be achieved in this way.

According to a preferred development of the invention, the first and/or second screen width is modulated in a location-dependent manner in that the positions of the screen elements of the relief screen or the point and/or line screen are given by a phase function φ(x,y), which is dependent on the position (x,y) of the raster element in the security element and whose function value indicates the deviation of the position of the raster element in a spatial direction from the position of a raster point in a regular raster, normalized to the unit interval [0,1], and where the phase function φ (x,y) varies depending on the location so that when the security element is tilted a movement effect, in particular a pumping or rotating effect, is created.

mit einer ganzen Zahl k ≠ 0 und einem Offsetwinkel α gegeben, wobei mod(x,y) die Modulofunktion und arg(z) das Argument einer komplexen Zahl darstellt. Im Fall eines Linienrasters wird dann bei der Betrachtung der visuelle Eindruck einer sich beim Kippen um den Bezugspunkt drehenden Windmühlen-Struktur mit |k| Flügeln erzeugt, wobei das Vorzeichen von k den Drehsinn der Flügel beim Kippen beschreibt.In an advantageous embodiment, the phase function φ(x,y) depends directly, in particular linearly, on the angle between the position (x,y) of the grid element and a fixed reference point (x ₀ , y ₀ ) of the security element, so that when the security element is tilted a rotation effect around the reference point (x ₀ , y ₀ ) arises. In this case, the phase function is preferably through $$\mathrm{\phi }\left(\mathrm{x}y\right)=\mathrm{model}\left(\left(\mathrm{a}+\mathrm{k}*\mathrm{bad}\left(\left(\mathrm{x}-{\mathrm{x}}_0\right)+\mathrm{i}\left(\mathrm{y}-{\mathrm{y}}_0\right)\right)/\left(2\mathrm{\pi }\right),1\right)\right)$$

with an integer k ≠ 0 and an offset angle α, where mod(x,y) is the modulo function and arg(z) is the argument of a complex number. In the case of a line grid, the visual impression of a windmill structure rotating around the reference point when tilted becomes visible with |k| Wings generated, where the sign of k describes the direction of rotation of the wings when tilting.

Further specific examples of phase functions that can be used advantageously and further details on phase functions can be found in the publication WO 2016/020066 A2 be taken, the disclosure content of which is included in the present application.

In particular, different movement effects or also 3D effects can be achieved with different phase functions. Both the first screen width, ie a screen width of the relief screen, and the second screen width, ie a screen width of the point and/or line screen, can be locally modulated according to the phase function. If you go, for example consists of a film strip as a security element, which contains a relief grid and is stuck to a banknote and overprinted with a dot and/or line grid in offset printing to create a movement effect, the following options exist in particular: M1) The relief grid on the film strip is regular and the printed grid is modulated as a function of location according to a phase function, or M2) the relief grid on the foil strip is modulated as a function of location according to the phase function and the printed grid is regular.

In practice, both variants can be advantageous. In a first embodiment, for example, a movement effect should result over the film strip, in which a bar pattern ( 1 ) runs up and down in opposite directions on the left and right halves of the strip when tilted forwards and backwards. If, for example, there are tolerances of ± 2 mm between the position of the foil strip and the printed image and if the printing grid is offset according to the phase function, the border between the bars on the foil moving in opposite directions will move up to 2 mm from the center of the foil due to these tolerances Foil strips (to the left or right)f, which can already be clearly noticed. If, on the other hand, the relief screen on the foil is modulated locally according to the phase function, the movement effect remains in the center of the strip even if the printed image migrates to the left or right relative to the strip. A regular print screen and a relief screen modulated according to the phase function are therefore advantageous for this design.

In a second embodiment, it may be desirable, for example, for a bar pattern to run oppositely to the left and right, respectively, on the upper and lower halves of the strip when tilted forwards and backwards. If you were to modulate the relief grid here according to the phase function and that Arranging print grids regularly, tolerances in the positioning of print and foil would cause the border between the bars running in different directions (to the left or right) (in the vertical direction) within the overprinted area to run up or down. In this embodiment, it is therefore advantageous to work with a regular relief screen and to modulate the print screen locally according to the phase function. The transition between the differently moved bars in the vertical direction is then always exactly in the middle of the overprinted area, regardless of the tolerances of the positioning of both screens.

In some applications it can also be advantageous to provide a location-dependent modulation by a phase function for both grids. The desired total modulation φ(x,y) is broken down into two phase functions φ _R (x,y) for the relief screen and φ _D (x,y) for the print screen, so that φ(x,y) = φ _R (x ,y) + φ _D (x,y) holds. In this case, the tolerances of the positioning are particularly critical, but also lead to security elements that are particularly forgery-proof. Assuming, for example, that the security elements described here are provided on banknotes of different denominations, for example denominations of 10 (10s) and 100 (100s), and assuming that a counterfeiter is familiar with the technology disclosed here and has the associated printing technology, in the event that both grids are completely regular, the counterfeiter could in principle remove the printed grid from the security element of a 10 and, by implementing the invention, generate a security element of a 100 from the security element of the 10. If, on the other hand, the two screens are modulated with different phase functions, the counterfeiter would also have to know the phase function of the relief screen in order to select a suitable print screen to be able to generate. A simple transfer is not possible even with knowledge of the invention.

The security element is advantageously a security thread, in particular a window security thread or a pendulum security thread, a tear-open thread, a security band, a security strip, a patch or a label for application to security paper, a document of value or the like.

The invention also includes a data carrier with a security element of the type described, wherein in a preferred embodiment at least one line grid of the security element covers the relief grid in some areas and extends in some areas outside of the relief grid onto the data carrier provided with the security element. The security element is thus secured on the data carrier and integrated into its design. A possible manipulation or even removal and transfer of the security element to another data carrier is not easily possible because of the required registering of the sub-areas mentioned. The partial area of the line screen that extends onto the data carrier outside of the relief screen advantageously acts like a halftone surface.

In an advantageous embodiment, the security element is arranged over a window area or a continuous opening of the data carrier. Such an arrangement is particularly advantageous in the described two-sided designs where one movement effect is visible in direct plan and another movement effect is visible when viewed through the window area or through opening.

The data carrier can in particular be a document of value, such as a banknote, in particular a paper banknote, a polymer banknote or a foil composite banknote, a share, a bond, a certificate, a voucher, a check, a high-quality admission ticket, but also an ID card , such as a credit card, bank card, cash card, authorization card, ID card, or passport personalization page. The data carrier can also be a decorative article, such as packaging, a memorabilia or a clothing label, or even an instruction leaflet for medicines. If the data carrier is a film element, this can also represent a packaging film that encloses further packaging.

• ein ein- oder zweidimensionales Reliefraster aus einer Mehrzahl von Rasterelementen und zumindest ein Punkt- und/oder Linienraster vertikal übereinander angeordnet werden, wobei
• das Reliefraster mit einer ersten Rasterweite p unterhalb von 500 µm in zumindest einer Raumrichtung ausgebildet wird,
• die Rasterelemente des Reliefrasters jeweils aus zumindest zwei, in unterschiedliche Richtungen gerichtet reflektierenden Reliefelementen gebildet werden,
• das zumindest eine Punkt- und/oder Linienraster in der genannten Raumrichtung mit einer zweiten Rasterweite q ausgebildet wird, wobei sich die zweite Rasterweite q von der ersten Rasterweite p um weniger als ein Fünftel unterscheidet, und/oder die erste Rasterweite p und/oder die zweite Rasterweite q ortsabhängig moduliert sind, so dass durch das Zusammenwirken von Reliefraster und Linienraster beim Kippen des Sicherheitselements ein Bewegungseffekt entsteht,
• und wobei der vertikale Abstand von Reliefraster und Punkt- und/oder Linienraster weniger als die halbe Rasterweite p beträgt.

The invention further includes a method for producing an optically variable security element of the type described above, in which

• a one- or two-dimensional relief grid consisting of a plurality of grid elements and at least one point and/or line grid are arranged vertically one above the other, wherein
• the relief screen is formed with a first screen width p below 500 µm in at least one spatial direction,
• the grid elements of the relief grid are each formed from at least two relief elements that reflect in different directions,
• the at least one point and/or line grid is formed in said spatial direction with a second grid width q, the second grid width q differing from the first grid width p differs by less than one-fifth, and/or the first screen width p and/or the second screen width q are modulated in a location-dependent manner, so that the interaction of the relief screen and the line screen creates a movement effect when the security element is tilted,
• and wherein the vertical distance between the relief screen and the point and/or line screen is less than half the screen width p.

In order to produce the relief grid, an embossing lacquer layer is advantageously applied to a carrier foil, embossed with a desired relief structure and provided with a reflection-increasing coating, in particular a metallization. In advantageous configurations, the reflection-increasing coating is applied in the form of a point and/or line grid, particularly preferably in the form of a line grid, or it is applied over the entire surface and then removed again in partial areas in order to obtain a reflection-increasing coating in the form of a point and/or line grid, particularly preferably in the form of a line grid.

In an advantageous method, the relief screen is applied to a desired data carrier, for example a banknote, with an adhesive layer. In particular in the case of two-sided security elements, the adhesive layer can be transparent, in particular transparently clear or transparently colored. The carrier film can remain in the layer structure, but in advantageous configurations it is removed after application in order to keep the thickness of the security element small.

If the relief screen is combined with one or more print screens (point and/or line screens), the print screens are advantageously used in offset printing, applied using indirect offset printing, flexographic printing or intaglio printing. A printing screen can be applied to the front and/or back of the security element, in particular using super-simultaneous printing. In an advantageous variant, the printed screens are printed after the relief screen has been transferred to a data carrier and, if appropriate, the carrier film has been pulled off. In other advantageous configurations, the security element is finished as a film element with a relief screen and printed screen and applied to a data carrier as a finished security element or, for example in the case of a window or pendulum security thread, embedded in a data carrier.

In a currently particularly preferred variant, the at least one dot and/or line screen is produced in intaglio printing. In addition to a high print resolution, this also enables the point and/or line grid to be detected tactilely.

A combination of an intaglio printing ink with a background color offers particular advantages, since in this way visually attractive color gradients and color sections can be created within a motif. In this context, it is particularly useful to combine differently designed areas in order to take into account the different resolutions of the printing processes (high resolution in intaglio printing, lower resolution in offset printing). For this purpose, for example, larger raster elements can be provided for printing in the background color and smaller raster elements for printing in the intaglio ink. Specifically, the intaglio printing ink can be provided in a smaller inner field, for example, while a larger outer field is printed with the background color.

The movement effect mentioned can in particular show moving lines or bars, also with several line or bar patterns moving in opposite directions. The movements can, but do not have to, be in a straight line, but can also be curved and, in the case of several line or bar patterns, intertwined. Pump and rotation effects, for example, can be considered as further movement effects. All movement effects are preferably colored, in particular multicolored.

Because of their small thickness, security elements according to the invention are particularly well suited for application to banknotes and other documents of value. A film element that contains embossed micromirrors can advantageously be used to produce the relief grid. As a result, a significantly higher brilliance can be achieved compared to conventional micromirrors produced in steel engraving. The use of small relief elements also enables a high resolution of the relief grid. Furthermore, the alignment of the relief elements can have a great influence on the appearance and the viewing angle, and good registration between the area with the moiré effect and any other authenticity features of the security element is possible.

Particularly in the packaging sector, it can also be advisable that the relief grid and the point and/or line grid are not firmly connected to one another, but are present on different packaging parts and are only superimposed in a checking position at a vertical distance of less than half the grid width.

• ein Sicherungsmittel mit einem ein- oder zweidimensionalen Reliefraster aus einer Mehrzahl von Rasterelementen, welches in zumindest einer Raumrichtung eine erste Rasterweite p unterhalb von 500 µm aufweist, und bei dem die Rasterelemente jeweils aus zumindest zwei, in unterschiedliche Richtungen gerichtet reflektierenden Reliefelementen gebildet sind, und
• ein Verifikationsmittel mit zumindest einem Punkt- und/oder Linienraster, das in der genannten Raumrichtung eine zweite Rasterweite q aufweist,
• wobei das Sicherungsmittel und das Verifikationsmittel so ausgebildet sind, dass beim vertikalen Übereinanderlegen von Sicherungsmittel und Verifikationsmittel in einer Überprüfungsstellung der vertikale Abstand von Reliefraster und Punkt- und/oder Linienraster weniger als die halbe Rasterweite p beträgt, und
• wobei sich die zweite Rasterweite q von der ersten Rasterweite p um weniger als ein Fünftel unterscheidet, und/oder die erste Rasterweite p und/oder die zweite Rasterweite q ortsabhängig moduliert sind, so dass durch das Zusammenwirken des Reliefrasters und des Punkt- und/oder Linienrasters beim Kippen der in der Überprüfungsstellung befindlichen Sicherheitsanordnung ein Bewegungseffekt entsteht.

Such an optically variable security arrangement is used to protect packaging and contains

• a security means with a one- or two-dimensional relief grid made up of a plurality of grid elements, which has a first grid width p of less than 500 µm in at least one spatial direction, and in which the grid elements are each formed from at least two relief elements reflecting in different directions, and
• a verification means with at least one point and/or line grid, which has a second grid width q in said spatial direction,
• wherein the security means and the verification means are designed such that when the security means and verification means are placed vertically one on top of the other in a checking position, the vertical distance between the relief grid and the point and/or line grid is less than half the grid width p, and
• wherein the second screen ruling q differs from the first screen ruling p by less than one-fifth, and/or the first screen ruling p and/or the second grid ruling q are modulated as a function of location, so that the interaction of the relief grid and the point and/or Line grid when tilting the security arrangement located in the review position creates a movement effect.

The other advantageous configurations of the relief grid and point and/or line grid correspond to the advantageous configurations of the grid in the security element described.

Suitable packaging has, in particular, at least one packaging part which, in the desired checking position, covers another packaging part. For example, two packaging parts can be pushed into one another, or one packaging part represents a lid for the other packaging part. A packaging part can also represent an outer packaging film or a banderole for the other packaging part. Securing means and/or verification means can be present in particular in a viewing window of the respective packaging part.

Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, which are not shown to scale and proportions in order to improve clarity.

Fig. 1

eine schematische Darstellung einer Banknote mit einem erfindungsgemäßen optisch variablen Sicherheitselement,

Fig. 2

ein erfindungsgemäßes Sicherheitselement im Querschnitt,

Fig. 3

zur Erläuterung der Entstehung des feinen Linienrasters in (a) nur das Reliefraster des Sicherheitselements der Fig. 2, und in (b) das visuelle Erscheinungsbild des Reliefrasters von (a),

Fig. 4

ein Sicherheitselement nach einem anderen Ausführungsbeispiel der Erfindung im Querschnitt,

Fig. 5

ein Sicherheitselement nach einem weiteren Ausführungsbeispiel der Erfindung im Querschnitt,

Fig. 6

in (a) eine Aufsicht auf das Reliefraster eines erfindungsgemäßen Sicherheitselements, und in (b) eine Aufsicht auf das vollständige Sicherheitselement, bei dem das Reliefraster von (a) mit zwei Drucklinienrastern kombiniert ist,

Fig. 7

in (a) und (b) Aufsichten wie in Fig. 6 für ein Sicherheitselement mit einem zweidimensionalen Reliefraster,

Fig. 8

in (a) und (b) Aufsichten wie in Fig. 6 und 7 für ein Sicherheitselement mit einem zweidimensionalen Reliefraster mit zwei unterschiedlichen Rasterweiten,

Fig. 9, 10

Aufsichten wie in Fig. 6(b), 7(b) und 8(b) für Sicherheitselemente nach weiteren Ausführungsbeispielen der Erfindung,

Fig. 11

ein Sicherheitselement nach einem weiteren Ausführungsbeispiel im Querschnitt,

Fig. 12

in (a) eine Aufsicht auf ein weiteres erfindungsgemäßes Sicherheitselement und in (b) und (c) das Erscheinungsbild des Sicherheitselements von (a) in senkrechter bzw. schräger Aufsicht, und

Fig. 13

eine Aufsicht auf das Reliefraster eines Sicherheitselements nach einem weiteren Ausführungsbeispiel.

Show it:

1

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

2

a security element according to the invention in cross section,

3

to explain the formation of the fine line screen in (a) only the relief screen of the security element 2 , and in (b) the visual appearance of the bump grid of (a),

4

a security element according to another embodiment of the invention in cross section,

figure 5

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

6

in (a) a top view of the relief screen of a security element according to the invention, and in (b) a top view of the complete security element in which the relief screen of (a) is combined with two printed line screens,

7

in (a) and (b) top views as in 6 for a security element with a two-dimensional relief grid,

8

in (a) and (b) top views as in Figures 6 and 7 for a security element with a two-dimensional relief grid with two different grid widths,

Figures 9, 10

supervisions as in 6(b), 7(b) and 8(b) for security elements according to further exemplary embodiments of the invention,

11

a security element according to a further embodiment in cross section,

12

in (a) a top view of a further security element according to the invention and in (b) and (c) the appearance of the security element from (a) in a vertical or oblique top view, and

13

a plan view of the relief grid of a security element according to a further embodiment.

The invention will now be explained using the example of security elements for banknotes. 1 shows a schematic representation of a bank note 10 which is provided with an optically variable security element 11 according to the invention. The security element 11 comprises a film strip 12 applied to the banknote substrate, which is provided in a sub-area 13 with a relief grid with a multiplicity of reflective relief elements.

The partial area 13 is also overprinted with a printed line grid 14 which continues on both sides of the foil strip 12 beyond the partial area 13 onto the banknote paper. The designs and the screen widths of the relief screen and the printed line screen 14 are matched to one another in the manner described in more detail below such that a (for example colored) movement effect occurs in the overlapping area 13 due to a moiré effect when the banknote 10 is tilted. For example, several colored bars 15, 16 can be visible in the overlapping area 13, which seem to run up or down when the bank note 10 is tilted back and forth.

The structure of a security element according to the invention and the creation of the conspicuous colored movement effect will now be described with reference to FIG figures 2 and 3 explained in more detail.

2 shows a security element 20 according to the invention in cross section. The security element 20 is arranged on a banknote substrate 10 by means of an adhesive layer 22 and contains an embossing lacquer layer 24 into which a relief grid 30 is embossed, which was provided with a metallization 32, for example made of aluminum or silver, before the adhesive layer 22 was applied.

The relief grid 30 itself consists of a plurality of adjoining elongated grid elements 34 whose longitudinal axis is in the representation of 2 extends into the drawing plane. Each raster element 34 consists of a plurality of parallel, line-like micromirrors 36, the mirror gradient of which changes in the figure from the left edge of the raster elements 34 to the right edge almost continuously from a first, negative gradient to a second, positive gradient. For example, the gradient of a micromirror 36 can be proportional to the signed distance x of the micromirror 36 from the center line 34-M of a raster element 34, so that the micromirrors 36 of a raster element 34 simulate the reflection behavior of a parabolic concave mirror.

The dimension of the raster elements 34 in the transverse direction, which at the same time represents the raster width p of the relief raster 30, is p=200 μm in the exemplary embodiment, and the width of the individual micromirrors 36 is around 22 μm. The dimension of the grid elements 34 and the micromirror 36 in the longitudinal direction, ie in the plane of the paper 2 into, is several millimeters or even centimeters, so it is significantly larger than the grid width p. In contrast, the width of the raster elements 34 and in particular the micromirrors 36 is below the resolution limit of the human eye, so that the raster elements 34 and in particular the micromirrors 36 cannot be resolved with the naked eye (or only to a small extent).

Nevertheless, when looking at the metalized relief screen 30, a fine line screen is created for an observer, as with reference to FIG 3 explained in more detail, where 3(a) only the relief grid of the security element 20 and 3(b) shows the visual appearance of the relief grid of (a). For example, if light 40 falls perpendicularly from above onto the relief grid 30, as in 3(a) shown, the reflection condition “angle of incidence equals angle of reflection” is only fulfilled for a micromirror 36-B of a raster element 34 for an observer 42.

in the in 3(b) In the top view 44 shown, this line-shaped micromirror 36-B therefore appears as a bright, fine line 46, while the areas 48 occupied by the other micromirrors reflect the incident light 40 in other spatial directions and therefore appear dark to the observer 42. Since the raster elements 34 and thus the micromirrors 36-B of the same orientation are repeated at a distance of the raster width p, the resulting fine line raster 46 also has a raster width p.

If the relief grid 30 of 3 from left to right (i.e. around a parallel to the longitudinal direction of the micromirror and thus in the plane of the paper 3(a) axis extending into it) is tilted, the position of that micromirror 36 for which the reflection condition is met moves to the right, so that the lines 46 of the fine line grid in the top view 44 for the viewer 42 also move to the right. Tilting to the left results in the opposite movement effect.

Coming back to the presentation of 2 contains the security element 20, in addition to the said relief grid 30, a printed layer in the form of a grid 50 of parallel spaced print lines 52 with a grid width q, which are printed on the opposite surface of the relief grid 30 of the embossing lacquer layer 24 with a translucent printing ink. The print lines 52 are aligned essentially parallel to the linear micromirrors 36 and the two grids are matched to one another in such a way that the second grid width q differs only slightly from the first grid width p. In the exemplary embodiment, the second grid width q is 10% smaller than the first screen width p, i.e. q = 180 µm.

The slightly different raster widths of the parallel rasters of the print lines 52 and the micromirrors 36 result in a moiré effect in which the observer sees a much coarser moiré line pattern 15,16 ( 1 ) becomes visible. With the difference of 10% selected here between the two screen rulings, a moiré magnification factor of about 10 results, that is, the moiré line pattern 15, 16 has about 10 times the screen ruling, in this case around 1.8 mm.

Since the bright lines of the fine line grid 46 run up or down when the bank note 10 is tilted, the Moiré line pattern 15, 16 also moves accordingly. If the fine lines 46 move by an entire period length, ie by p=200 μm here, the bars 15 of the Moiré line pattern also move by one period length, ie by 1.8 mm. The microscopic movement effect of the line grid 46, which is hardly visible to the naked eye, is thus increased by the moire effect to a movement that is easily perceptible to the viewer.

In order to achieve a small thickness of the security element 20, the grid 50 of the printed lines 52 is arranged at a small vertical distance h above the relief grid 30. In the exemplary embodiment, the vertical distance h is, for example, only about 10 μm, ie only one twentieth of the grid width p.

The use of a translucent color, for example red, for the printed line grid 52 also means that the moiré line pattern 15, 16 consists of red and white (light) lines in alternation.

Overall, in the manner described, an optically variable security element is produced with a one-dimensional relief grid made up of a plurality of grid elements which are each formed from a plurality of line-like micromirrors directed in different directions and reflecting. The relief screen is combined with a printed line screen arranged above the relief screen and, when tilted, shows a particularly colored movement effect based on a Moiré effect. Because of its small thickness, the security element described is particularly well suited for application to banknotes and other documents of value.

The described relief grid 30 made of micromirrors 36 can be provided particularly advantageously in the form of a foil element, in which the micromirrors 36 are molded into an embossing lacquer 24 applied to a carrier foil, for example a radiation-curing or thermoplastic lacquer, and covered with a reflection-increasing coating, for example an aluminum metallization 32 are provided. By using a foil with embossed micro-mirrors, a particularly high brilliance of the reflecting surfaces and thus the optically variable, colored movement effect is achieved.

The film element can be applied to a banknote substrate and the carrier film can be removed again after application to reduce the thickness, so that the embossing lacquer layer 24, the metallization 32 and the adhesive layer 22 are then essentially present on the banknote 10, as in 2 shown. In practice, further layers can be provided here, although they are not essential for the invention, such as a protective lacquer layer, ink acceptance layer or primer layer.

The grid 50 of the print lines 52 is then printed over this layer sequence in the manner described above in order to obtain the complete security element 20 .

The grid of the printed lines 50, 14 can continue beyond the edge of the relief grid 30 or the foil strip 12, as in FIG 1 shown. On the one hand, this visually integrates the movement effect particularly well into the banknote design, and on the other hand, security against forgery is increased, since a foil strip 12 detached from a banknote would have to be glued to a counterfeit note with an exact register in order to preserve the registration of foil strip 12 and printed line grid 14. With such a design, a colored movement effect occurs visually in the overlapping area 13, while the printed line screen 14 outside of the overlapping area 13 essentially acts as a homogeneous halftone surface due to the small spacing of the printed lines (q=180 μm).

In the embodiment of 2 All raster elements 34 are of the same design, with the gradients of the micromirrors 36 being selected in each raster element 34 in such a way that the raster element 34 simulates the reflection behavior of a parabolic concave mirror. It is also possible to have two or more different raster elements in a relief raster 30 . For example, the embodiment of 4 a security element 60, which in principle at 2 follows the structure described, in which not only first grid elements 34 are provided, which simulate the reflection behavior of a parabolic concave mirror, but also second grid elements 62, which simulate the reflection behavior of a parabolic convex mirror, as on the left-hand edge of the 4 shown.

Compared to the raster elements 34, the gradient of the micromirrors 36 is inverted in the second raster elements 62, ie runs from the left edge to the right edge from a first, positive gradient to a second, negative gradient. At the points where second raster elements 62 are provided instead of first raster elements 34, the position of the generated fine lines 46 changes in the bright line raster, and the lines generated by the curved mirror-like raster elements 62 are opposite to those generated by the concave mirror-like raster elements 34 Lines show an inverted movement behavior, since the sequence of mirror gradients is just inverted. For example, the lines generated by curved mirror-like raster elements 62 can run in an upward direction when the security element is tilted, while the lines generated by the concave mirror-like raster elements 34 run downward at the same time. The movements can also be curved and intertwined, for example within bands in the form of a cord or a double helix.

It is also possible to provide more than one line screen arranged over the relief screen. figure 5 shows a security element 54, which in principle 2 follows the structure described, but in which two printing line grids with parallel printing lines 52, 56 are provided. In this case, the print lines 56 are printed, for example with green translucent ink, in register between the red translucent print lines 52 . The colored movement effect of the security element 54 then shows a pattern of migrating, alternating red and green bars. Such register-accurate printing is easily possible, especially with small screen widths q of about 100 μm in banknote printing, but is very difficult for a potential forger to reproduce.

In addition to adding another color to a single motion effect, another line grid can also create a second, different motion effect. For example, a first, e.g. red, print line screen can have a screen width q ₁ that is slightly larger than the first screen width p, while a second, e.g. green, print line screen has a screen width q ₂ that is slightly smaller than the first screen width p. When the security element is tilted, the red and green bars created by the moiré effect then move in opposite directions. In the case of a two-sided security element, a further movement effect can also be produced on the opposite side of the relief grid and be visible from this side.

In other configurations, with a fixed second screen width q, the first screen width p can vary locally. Interesting effects also result when the first screen width p and the second screen width q are fixed, but the curvature or the slope of the relief elements forming the screen elements is locally varied. For example, when designing the 2 the pitch of the micromirrors 36 in the middle raster element 34 can be twice as large as in the adjacent raster elements, and a modulation of the movement effect can thereby be produced. Said variation can then be continued periodically.

In the configurations described so far, the raster elements each consist of linear micromirrors. However, it is also possible for the raster elements to be formed by corresponding Fresnel mirror structures, ie by Fresnel lenses or Fresnel lens sections, which are provided with a reflection-increasing coating. The Fresnel mirror structures can correspond to both a concave and a convex curvature, or represent a mixed form of concave and convex partial areas.

For illustration shows 6(a) a top view of the relief grid 70 of a security element according to the invention, which consists of a plurality of consecutive elongated grid elements 72, which can be seen in the representation of FIG 6(a) extend from left to right and connect to each other from top to bottom. Each raster element 72 forms a cylindrical Fresnel mirror structure which corresponds to a concave curvature of a cylindrical Fresnel diverging lens and is provided with a reflective aluminum metallization, for example. In this configuration, the individual relief elements 74 are not defined by linear micromirrors 36 as in FIG 2 , but formed by the coated line-shaped zones of the negative Fresnel lens and therefore generally have curved reflecting surfaces.

Fig.6(b) shows a top view of the complete security element 80, in which the relief grid 70 of 6(a) is combined with two print line screens with print lines 82, 84 of different colors. Here, too, a moiré effect results from the interaction of the relief grid 70 and the grid of the printed lines 82, 84, through which the viewer sees a colored movement effect with two differently colored bars, which when the security element 80 is tilted in front of a light background on and move off

When modifying the 7 the relief grid is not one-dimensional but two-dimensional. Fig.7(a) shows a plan view of only the relief grid 90 of the security element 100 and Fig.7(b) a top view of the complete security element 100. The two-dimensional relief grid 90 consists of a plurality of raster elements 92 adjoining one another in both spatial directions, the raster widths p ₁ , p ₂ in the two spatial directions being the same in the exemplary embodiment shown and both amounting to 200 μm, for example. Each raster element 92 forms a spherical Fresnel mirror structure, which corresponds to a concave curvature of a spherical Fresnel diverging lens and is provided with a reflective aluminum metallization, for example. In this configuration, the individual relief elements 94 are formed by the coated annular zones of the Fresnel diverging lens and have curved reflection surfaces.

In the case of the complete security element 100, the relief grid 90 is Fig.7(a) combined with two print line screens with print lines 82, 84 of different colors. In the case of a two-dimensional relief grid, too, a moiré effect results from the interaction of the relief grid 90 and the grid of the printed lines 82, 84, through which the viewer sees a colored movement effect with two differently colored bars that move in front of you when the security element 100 is tilted move light background up and down.

In the embodiment of 7 Of the two screen widths p ₁ , p ₂ , only screen width p ₂ has an effect on account of the orientation of printing lines 82, 84 in the x-direction in the moiré effect. In other designs, however, the print lines can also be oriented in the y-direction, or a first print-line grid contains print lines in the x-direction and a second print-line grid contains print lines in the y-direction, so that both grid widths of the relief grid come into play.

In the embodiment of 8 the relief grid is two-dimensional with two different grid widths p ₁ and p ₂ in the x and y directions. 8(a) shows a top view of only the relief grid 110 of the security element 120 and Fig.8(b) shows a top view of the complete security element 120. The two-dimensional relief grid 110 consists of a plurality of grid elements 112 adjoining one another in both spatial directions, with the grid widths p ₁ , p ₂ being different in the two spatial directions and, for example, p ₁ = 300 μm and p ₂ = 150 µm. Each raster element 112 forms an elliptical Fresnel mirror structure, which corresponds to a convex curvature of an elliptical Fresnel converging lens and is provided with a reflective aluminum metallization, for example. In this configuration, the individual relief elements 114 are formed by the coated annular zones of the Fresnel diverging lens and have curved reflection surfaces.

In the full security element 120, the relief grid 110 is the 8(a) combined with two print line screens with print lines 122, 124 of different color and orientation. The print lines 122 of the first print line grid lie parallel to the y-direction and have a grid width q1, which differs only slightly from the grid width _p1 . The print lines 124 of the second print line grid lie parallel to the x-direction and have a grid width q ₂ which differs only slightly from the grid width p ₂ . Depending on the specific selection of the screen widths q ₁ , q ₂ in relation to the screen widths p ₁ , p ₂ , various movement effects can be generated in which, for example, the Moiré line screen changes when the security element is tilted from right to left and when tilted from top to bottom moved down at different speeds.

9 shows another embodiment of the invention, in which the relief grid 110 of the security element 140 as in connection with 8 described is formed. The relief grid 110 is combined with a printed dot grid 142, the grid dots 144 of which are each in the form of the euro symbol (€) in the exemplary embodiment. Like the relief raster 110, the printed dot raster 142 is two-dimensional and has two different raster widths q ₁ and q ₂ in the x and y directions. The screen width q ₁ differs only slightly from the screen width p ₁ and the screen width q ₂ differs only slightly from the screen width p ₂ . Depending on the specific selection of the screen widths q ₁ , q ₂ in relation to the screen widths p ₁ , p ₂ , various movement effects can be generated in which, for example, the moire-enlarged € symbols move from right to left when the security element is tilted and when it is tilted move from top to bottom at different speeds.

The embodiment of 10 is a modification of the embodiments of FIG 7 and 8th . First, the relief grid 110 of the security element 150 is again as in connection with FIG 8 trained already described. The relief grid 110 is similar to the embodiment of FIG 7 combined with two print line screens with print lines 152, 154 of different colors. The grids of the printed lines 152, 152 each have a grid width q ₂ in the y-direction, which differs only slightly from the grid width p ₂ of the relief grid.

In contrast to the design of 7 However, the pressure lines 152, 154 have additional recessed areas 156 and 158, respectively, which are designed in the form of a € symbol. The recessed areas 156 and 158 are arranged in the x-direction with a grid width q1, which at most differs slightly from the grid width _p1 of the relief grid. Because of The interaction of the two-dimensional relief grid 110, the grid of the print lines 152, 154 and the grid of the gaps 156, 158 in the print lines results in a colored movement effect for the viewer with two differently colored bars, which are moiré-enlarged gaps in the form of the € symbol demonstrate. The bars move up and down together with the gaps when the security element 150 is tilted in front of a light background. By suitably matching the screen widths p ₁ and q ₁ , it can also be achieved that the moiré-enlarged gaps appear to shift within the bars from right to left when the security element is tilted.

In the designs of Figures 7 to 10 the grid elements do not necessarily have to connect to one another and completely fill out the plane of the security element, but can also be arranged at a distance from one another and themselves be designed in the form of a motif. Figure 12(a) FIG. 12 shows a top view of a security element 160 with a two-dimensional relief raster 162 made up of a plurality of raster elements 164 arranged at a distance, each with a star-shaped outline. Except for the motif-shaped outline, the grid elements 164 are like the grid elements 92 of 7 formed, so each form a spherical Fresnel mirror structure, which corresponds to the concave curvature of a spherical Fresnel diverging lens and is provided, for example, with a reflective aluminum metallization. The relief grid 162 is combined with two printed line grids with printed lines 82, 84 of different colors, for example red printed lines 82 and yellow printed lines 84.

When the security element 160 is viewed, the moire effect produces enlarged moire macro information with the shape of the relief elements 164. In the exemplary embodiment, a plurality of approximately arises moire magnified stars 166, 168, as in 12(b) and (c) illustrated, which show the appearance of the security element 160 in a vertical or oblique view. A tilting of the security element 160 leads on the one hand to the enlarged stars 166, 168 moving. In addition, because of the different colors of the printed lines 82, 84, a color change occurs, so that, for example, when viewed perpendicularly ( Fig. 12(b) ) red star 166 when viewed obliquely ( 12(c) ) can appear as a yellow star 168 and vice versa. It is understood that motif-shaped spaced relief elements not only in the design of 7 , but can be used in all the configurations described instead of mutually adjoining relief elements.

A location-dependent modulation of the relief grid 170 by location-dependent shift in focus is in 13 illustrated, which is similar to Fig.7(a) shows only the relief grid 170 of a security element according to the invention. It goes without saying that the relief grid 170 is combined in the manner described with at least one point and/or line grid to form a complete security element.

The two-dimensional relief raster 170 consists of a plurality of raster elements which adjoin one another in both spatial directions and have spherical Fresnel mirror structures Fig.7(a) already described in more detail. For illustration, in 13 the raster elements 172 of the upper line shown are designed without a shift in the center of gravity, the center of the spherical Fresnel mirror structure 176 is therefore also in the center of each raster element 172 in these elements. The lower line shows raster elements 174 with different shifts in the center of gravity, in which the center of the spherical Fresnel - mirror structure 176 does not coincide with the center of the grid elements 174, but has a certain displacement (Δx, Δy). In practice, this shift is advantageously given by a formulaic relationship, in order, for example, to produce the effect of a pumping circuit.

Furthermore, it is also possible to provide a subset of the raster elements with a shift in the center of gravity by a specific displacement value in order to contrast the information formed by the shape of the subset from its surroundings. This variant is particularly useful in combination with dot and/or line screens of different colors, with the offset value of the screen elements being advantageously matched to the distance between the dot and/or line screens such that the information formed by the subset appears with maximum color contrast. When the security element is tilted, the opposite color impression can then result at a specific tilt angle.

11 shows a security element 130 according to a further exemplary embodiment of the invention in cross section. The security element 130 comprises a full-surface printed layer 138 arranged on the banknote substrate 10, for example a red color layer, a transparent hot-melt adhesive layer 22 and an embossing lacquer layer 24, into which a relief grid 30 is embossed, which is provided with a metallization applied in the form of a line grid 132.

The relief grid 30 consists of a plurality of adjoining elongated grid elements 34, for example, from several line-like micromirrors as in the embodiment of FIG 2 , or a cylindrical Fresnel mirror structure as in the embodiment the 6 can exist. The relief screen 30 has a first screen width p below 500 μm.

The line screen 132 present directly on the relief screen 30 consists of alternating metallic lines 134 and demetalized lines 136 and has a second screen width q, which differs from the first screen width p only slightly, for example by 5%. In this exemplary embodiment, the line grid 132 of the metallic lines 134 and demetallized lines 136 is present directly on the relief grid 30, so that the vertical distance between the relief grid 30 and the line grid 132 is equal to zero.

The line grid 132 can be produced, for example, by full-area metallization of the embossed embossing lacquer layer 24 and subsequent demetallization in certain areas using a suitable demetallization method, for example by the one from the publication WO 99/13157 A1 known washing processes. Alternatively, for example, an etching mask can also be printed and the demetallization can be carried out in an etching process. Laser demetallization is also conceivable. As with the printed line screens, the relief screen 30 can also be combined with several metal line screens, which can also have different screen widths and/or different line orientations.

When viewing the security element 130, the red printed layer 138 can be seen in the demetallized line areas 136, so that these appear as red lines. Interacting with the fine line screen created by the metallized line areas 134, the screen of red lines produces a moiré effect and an enlarged moiré line pattern, as generally described above.

Since the printing layer 138 appears in the demetallized line areas 136, there is a perfect register between the red lines visible there and the metallic lines 134.

The printed layer 138 can also be multicolored and thus produce differently colored movement effects in different partial areas of the security element 130 .

Alternatively or in addition to print layer 138, embossing lacquer layer 24 itself can also be transparent in color, or a full-area printing layer arranged on embossing lacquer layer 24, for example a transparent or translucent (glazing) color layer, can be provided in order to produce a colored line grid. Thus, the colored embossing lacquer layer 24 or the colored printing layer arranged on the embossing lacquer layer 24 appears as colored lines, particularly in the demetallized line regions 136 .

Reference List

10

bank note

11

security element

12

foil strips

13

subarea

14

print line grid

15:16

colored bars

20

security element

22

glue layer

24

embossing layer

30

relief grid

32

metallization

34

grid elements

34-M

Center line of a grid element

36, 36-B

micromirror

40

light

42

viewer

44

At sight

46

fine lines

48

other areas

50

grid

52

pressure lines

54

security element

56

pressure lines

60

security element

62

second grid elements

70

relief grid

72

grid elements

74

relief elements

80

security element

82, 84

pressure lines

90

relief grid

92

grid elements

94

relief elements

100

security element

110

relief grid

112

grid elements

114

relief elements

120

security element

122,124

pressure lines

130

security element

132

line grid

134

metallic lines

136

demetallized lines

138

print layer

140

security element

142

pressure point grid

144

grid dots

150

security element

152, 154

pressure lines

156, 158

recessed areas

160

security element

162

relief grid

164

grid elements

166, 168

enlarged stars

170

relief grid

172,174

grid elements

176

spherical Fresnel mirror structure

Claims (21)

1. An optically variable security element (20) for securing valuable articles, having

   - a one- or two-dimensional relief grid (30) that is composed of a plurality of grid elements (34) and that has a first line screen p below 500 µm in at least one spatial direction and in which the grid elements (34) are each formed from at least two relief elements (36) that are directionally reflective in different directions, and

   - having at least one dot and/or line grid (50) that is arranged vertically above or below the relief grid (30) and has a second line screen q in said spatial direction, the second line screen q differing from the first line screen p by less than one-fifth, and/or the first line screen p and/or the second line screen q being location-dependently modulated such that a movement effect is created by the interplay of the relief grid (30) and the dot and/or line grid (50) when the security element (20) is tilted,

   - and the vertical spacing between the relief grid (30) and the dot and/or line grid (50) being less than half the line screen p.
2. The security element according to claim 1, characterized in that at least one, preferably all, of the dot and/or line grids are developed as line grids.
3. The security element according to claim 2, characterized in that at least one line grid is a print line grid that preferably is formed at least in a sub-region from a plurality of substantially parallel print lines having a spacing q.
4. The security element according to claim 3, characterized in that the print line grid is separated from the relief grid by a spacing layer, the spacing layer advantageously including an embossing lacquer layer in which the relief elements of the relief grid are embossed.
5. The security element according to at least one of claims 1 to 4, characterized in that the relief elements of the relief grid are provided with a reflection-increasing coating, especially a metalization.
6. The security element according to at least one of claims 1 to 5, characterized in that at least one dot and/or line grid is formed by a reflection-increasing coating, present in dot and/or line grid form, of the relief elements of the relief grid, especially, that the relief grid is combined with a background layer, especially a contiguous ink layer, that lies below the reflection-increasing coating.
7. The security element according to claim 6, characterized in that the relief grid is combined with a colored transparent or translucent layer that lies above the reflection-increasing coating.
8. The security element according to at least one of claims 1 to 7, characterized in that the vertical spacing between the relief grid and the line grid is less than one-fifth, preferably less than one-tenth of the line screen p, especially less than 15 µm.
9. The security element according to at least one of claims 1 to 8, characterized in that the relief grid is a one-dimensional grid that is composed of a plurality of elongated grid elements, that has said line screen p, and in which the grid elements are each formed from at least two line-type relief elements that are directionally reflective in different directions, especially, that the grid elements are each formed from a plurality of line-type micromirrors or from a cylindrical Fresnel mirror structure.
10. The security element according to at least one of claims 1 to 8, characterized in that the relief grid is a two-dimensional grid that is composed of a plurality of grid elements, that has said line screen p in a first spatial direction, and in which the grid elements are preferably each formed from at least two, preferably at least three, particularly preferably at least four relief elements that are directionally reflective in different directions, especially, that the grid elements are each formed from a circular or elliptical arrangement of a plurality of micromirrors or a spherical or elliptical Fresnel mirror structure.
11. The security element according to claim 10, characterized in that the grid elements are arranged having a motif-shaped contour and spaced apart from one another.
12. The security element according to at least one of claims 1 to 11, characterized in that the grid elements are each formed from a plurality of relief elements that are directionally reflective in different directions, especially in a one-dimensional grid are formed from at least 10 line-type relief elements that are directionally reflective in different directions, and in a two-dimensional grid are formed from at least 10 x 10 relief elements that are directionally reflective in different directions.
13. The security element according to at least one of claims 1 to 12, characterized in that the reflective relief elements of each grid element are arranged and developed in such a way that the grid element produces the reflection behavior of a concave or convex curvature.
14. The security element according to at least one of claims 1 to 13, characterized in that the grid elements are all developed to be homogeneous, or that the relief grid includes two or more different grid elements that preferably each produce different movement effects when the security element is tilted.
15. The security element according to at least one of claims 1 to 14, characterized in that the dot and/or line grid comprises a plurality of parallel lines that run substantially perpendicular to the first spatial direction.
16. The security element according to at least one of claims 1 to 15, characterized in that two or more dot and/or line grids that are arranged vertically above or below the relief grid are provided, especially in that at least one dot and/or line grid is arranged above and at least one dot and/or line grid is arranged below the relief grid.
17. The security element according to at least one of claims 1 to 16, characterized in that the first line screen p is fixed and the second line screen q is location-dependently modulated, or in that the second line screen q is fixed and the first line screen p is location-dependently modulated.
18. The security element according to at least one of claims 1 to 17, characterized in that the first and/or second line screen is location-dependently modulated in that the positions of the grid elements of the relief grid or of the dot and/or line grid are given by a phase function φ(x,y) that depends on the position (x,y) of the grid element in the security element and whose function value indicates the deviation of the position of the grid element from the position of a grid point in a regular grid, normalized to the unit interval [0,1], and the phase function φ(x,y) varying location dependently in such a way that a movement effect, especially a pump or rotation effect, is created when the security element is tilted.
19. The security element according to at least one of claims 1 to 18, characterized in that the security element is a security thread, especially a window security thread or a pendulum security thread, a security band, or a security strip.
20. A data carrier having a security element according to at least one of claims 1 to 19, preferably at least one line grid of the security element covering the relief grid in sub-regions and in sub-regions extending outside the relief grid to the data carrier provided with the security element.
21. A method for manufacturing an optically variable security element (20) according to one of claims 1 to 19, in which

    - a one- or two-dimensional relief grid (30) composed of a plurality of grid elements (34) and at least one dot and/or line grid (50) are vertically stacked one on top of another,

    - the relief grid (30) being developed having a first line screen p below 500 µm in at least one spatial direction,

    - the grid elements (34) of the relief grid (30) each being formed from at least two relief elements (36) that are directionally reflective in different directions,

    - the at least one dot and/or line grid (50) being developed having a second line screen q in said spatial direction, the second line screen q differing from the first line screen p by less than one-fifth, and/or the first line screen p and/or the second line screen q being location-dependently modulated such that a movement effect is created by the interplay of the relief grid (30) and the dot and/or line grid (50) when the security element is tilted,

    - and the vertical spacing between the relief grid and the dot and/or line grid being less than half the line screen p.

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