CN113950414A

CN113950414A - Optically variable security element

Info

Publication number: CN113950414A
Application number: CN202080042205.XA
Authority: CN
Inventors: G.多夫; B.托伊费尔
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient GmbH
Priority date: 2019-08-14
Filing date: 2020-08-07
Publication date: 2022-01-18
Anticipated expiration: 2040-08-07
Also published as: EP4013625A1; CN113950414B; WO2021028076A1; EP4013625B1; DE102019005705A1

Abstract

The invention relates to an optically variable security element (14) having different visual appearances of opposite sides (16, 18). According to the invention, the security element (14) has a multicolored reflective surface area (20) which contains two relief structures (24, 34) which are arranged in different height levels in the z direction and form an upper relief structure (34) close to the upper side (16) of the security element and a lower relief structure (24) close to the lower side (18) of the security element. The lower relief structure (24) is provided with a lower color coating (26) following a relief course and the upper relief structure (34) is provided with an upper color coating (36) following a relief course. A light-transmitting, colored flat structure (44) is arranged on a height level between the two relief structures (24, 34) in the z-direction, wherein the two relief structures (24, 34) and the flat structure (44) overlap in an overlap region. The upper color coat (36) has at least one recess (35) in the overlap region, in which recess the lower relief structure (24) emerges with a combined color effect of at least the translucent colored flat structure (44) and the lower color coat (26), when viewed from the top. The lower color coating (26) has at least one recess (25) in the overlap region, in which the upper relief structure (34) emerges, when viewed from the underside, with a combined color effect of at least the translucent colored flat structure (44) and the upper color coating (36).

Description

Optically variable security element

The invention relates to an optically variable security element for providing security to a valuable article, which security element exhibits different visual appearances when the security element is viewed from the top and the opposite bottom. The invention also relates to a method for producing such a security element and to a data carrier equipped with such a security element.

Data carriers, such as value documents or identity documents and other valuable articles, such as branded goods, are often provided with security elements to provide security, which allow the authenticity of the data carrier to be checked and at the same time serve as protection against unauthorized copying. The security element can be designed, for example, in the form of a security thread embedded in a banknote, a cover film for a perforated banknote, an applied security strip, a self-supporting transfer element or in the form of a characteristic region printed directly onto the document of value.

Security elements with a viewing-angle-dependent or three-dimensional appearance play a special role in the assurance of authenticity, since they cannot be reproduced even with the most modern copy machines. For this purpose, security elements are equipped with optically variable elements which provide the viewer with different image impressions from different viewing angles and, for example, display different color or brightness impressions and/or different graphic designs (Motiv, or visual objects) depending on the viewing angle. In the prior art, motion effects, pump effects, depth effects or tilting effects are described, for example, as optically variable effects, which are realized by means of holograms, microlenses or micromirrors.

Starting from this, the object of the invention is to further improve the security and visual appeal of optically variable security elements of the type according to the invention. In particular, an optically variable security element is to be provided which shows two or more different appearances or different color effects from opposite viewing directions, and which can ideally also be produced simply and cost-effectively.

This object is achieved according to the invention by the features of the independent claims. The invention is characterized in that it is provided with a plurality of design elements.

In order to solve the stated problem, the invention comprises optically variable security elements which, when viewed from the top and from the opposite bottom, each show a different visual appearance.

The plane extension of the security element defines a plane and a z-axis perpendicular to said plane. The security element has a multicolored reflective surface region which contains two relief structures which are arranged in different height levels in the z direction and form an upper relief structure close to the upper side of the security element and a lower relief structure close to the lower side of the security element.

The lower relief structure is provided with a lower color coating following the relief course and the upper relief structure is provided with an upper color coating following the relief course.

A light-transmitting, colored flat structure is arranged in the z-direction at a height level between two relief structures. Furthermore, the two relief structures and the flat structure overlap in an overlap region. The upper color coating has at least one recess in this overlap region, in which recess the lower relief structure appears with a combined color effect of at least the translucent colored flat structure and the lower color coating when the security element is viewed from above. The lower color coating has at least one recess in the overlap region, in which the upper relief structure appears with a combined color effect of at least the translucent colored flat structure and the upper color coating when the security element is viewed from the underside.

The overlap of the structures may be partial or complete, it being possible in particular for the two relief structures and the flat structure to be designed congruent to one another. The overlap here relates to the relative lateral position of the relief structure and the flat structure in a plane defined by the surface extension of the security element.

The terms upper side and lower side denote two opposite main sides of the flat security element in a defined orientation. The security element is applied with its underside to the data carrier in advance, so that the underside faces the data carrier and the upper side points away from the data carrier. In contrast, for a separately present data carrier or a security element embedded in a data carrier, each of the opposite main sides can generally be considered as the upper side or the lower side.

Within the scope of the present description, for the sake of easier reference, the empty space in the upper color coat or the lower color coat is generally indicated in plural. Even if plural forms are applied, the plural forms should also include a case where only one vacant portion is present in the upper or lower color coat layer.

In an advantageous embodiment, the recesses in the upper color coating and the recesses in the lower color coating are arranged without overlapping. This means that the lower color coat is visible in each of the cutouts of the upper color coat and the upper color coat is visible in each of the cutouts of the lower color coat. In this embodiment, therefore, the perspective through the surface region cannot be achieved by aligned recesses in the two color coatings.

In a further embodiment, provision is made for, in addition to the recesses arranged in the upper and lower color coats in a non-overlapping manner, also to provide mutually overlapping recesses in the two color coats, which recesses enable a perspective through the surface region from one viewing direction. The viewing direction may be a vertical viewing direction, but may also be an oblique viewing direction not exceeding a typical angle up to 60 °. The mutually overlapping recesses can be arranged in particular in the form of a grid, for example a dot grid, which forms a logo, a pattern or a coding. The dimensions of the grid elements are advantageously selected to be so small that a perspective through the overlapping cutouts is possible only over a small angular range of a few degrees. The pattern formed by the grid is therefore visible only in a small angular range, which provides additional authenticity protection of the security element. The diameter of the grid points or the size of the grid elements may especially be below 1mm or even below 300 μm.

In one expedient configuration, the recesses in the upper and lower color coats, which are arranged without overlapping, are arranged in a staggered manner, i.e. they alternate with one another in a staggered manner along the surface extent of the surface region. In the interlaced area, the change in color is visible both when viewed from the upper side and when viewed from the lower side.

In an alternative, likewise expedient embodiment, the recesses in the upper color coating and the lower color coating, which are arranged without overlapping, are arranged in a block-like manner at a distance from one another. In particular, two separate block-shaped regions can be provided precisely, wherein in the first block-shaped region, only the upper color coating has a recess and the lower color coating is designed continuously. In the second block region, on the other hand, there are only recesses in the lower color coating, while the lower color coating is designed continuously. In this way, two independent effect regions are realized in the security element, which effect regions display a color change only when viewed from the top (first block region) or only when viewed from the bottom (second block region).

In an advantageous embodiment, it is provided that the color effects of the relief structure, the color coating and the flat structure are adapted to one another such that, when viewed from the top, the security element exhibits a first color impression outside the recess of the upper color coating and a second color impression different from the first color impression within the recess. Furthermore, the security element, when viewed from the underside, exhibits a third color impression outside the recess of the lower color coating and a fourth color impression different from the third color impression within the recess. It has proven to be particularly advantageous if the color effects of the relief structure, the color coating and the flat structure are adapted to one another in such a way that all four color impressions differ from one another. The colour effect of the relief structure comprises in particular the colour effect of a lacquer layer in which the relief structure is formed and the colour effect of an overlaminate lacquer layer in which the relief structure is formed.

The general term "color effect" herein includes both color and colorlessness. The term "color impression" is used for the overall color impression produced by one or more color effect elements. In particular, for example, a colorless transparent embossing lacquer layer (colorless color effect) with a flat structure of yellow finish (laserenden) (yellow color effect) and a rear-applied aluminum metallization (silver-colored bright color effect) produce a yellow bright color impression. If, instead of a colorless embossing lacquer, a lustering blue embossing lacquer is used, a green, shiny color impression is produced by color mixing.

Advantageously, the light-transmitting colored flat structure is formed by a laminating lacquer layer, for example a glossing-dyed laminating lacquer layer, by a dyed primer layer or a printed color layer. As colorant, the light-transmitting colored flat structure may contain, in particular, a dyed pigment and/or dye.

The light transmission of the flat structure is advantageously between 20% and 80%. In contrast to the relief structure, the light-transmitting colored flat structure is not structured in height, but rather is designed flat. The flat structure can in particular be applied directly to a carrier film or a flat base layer, for example a paint layer, which has a levelling effect.

The upper and/or lower color coating is preferably a reflective color coating, in particular a reflective opaque color coating. The one or both color coatings can be formed in particular by a metallization, for example a metallization made of aluminum, silver or an alloy of, for example, copper and aluminum, by a thin-layer structure, in particular a color-gradient thin-layer structure, a gold-blue or silicon-aluminum thin layer. The first and/or second color coat can also present a glossed image consisting of a plurality of glossed colors (lasierenden facebe) which is backed by an opaque metallisation, for example made of aluminium. It is also conceivable to use the emission color, in particular the fluorescence color, together with a metallization (or a metal mirror) as a color coating. The first and/or second color coating can also be formed by structural colors, in particular by nano-and binary structures, which are imprinted on or in the micromirrors of the micromirror device. Finally, nanoparticle colors (or called color inks) are also considered as color coatings, for example gold-blue particles, different effect pigments, color-tilted pigments or super-silver.

The upper and/or lower relief structure is advantageously molded in a transparent or a lusterized embossing lacquer layer. In this case, it can be provided in particular that the upper relief structure is formed in the transparent embossing lacquer layer and the lower relief structure is formed in the lustering embossing lacquer layer. In an advantageous embodiment, the upper and/or lower relief structure is flattened by a cover layer, which may likewise be transparent or pigmented.

The upper relief structure and/or the lower relief structure are particularly advantageously formed by a micromirror device having directional micromirrors. The micromirrors are formed here in particular by non-diffractive mirrors and do not produce a color separation. Preferably, flat mirrors, concave mirrors and/or fresnel-type mirrors can be used here. The lateral dimensions of the micromirror are advantageously below 20 μm, preferably below 10 μm, but on the other hand preferably above 2 μm, especially above 3 μm or even above 5 μm. Instead of micromirrors, in principle, other relief structures, in particular embossed fresnel lenses, concave mirrors, hologram structures, nano-structures or diffractive blazed gratings, can also be used.

The orientation of the micromirrors of the upper and/or lower relief structure is advantageously changed in a position-dependent manner in order to produce a correspondingly predetermined pattern, in particular a three-dimensionally effective pattern or movement pattern. The orientation of each micromirror can be freely selected and is determined substantially only by the predetermined pattern, but not by the orientation of the adjacent micromirrors.

The two relief structures advantageously provide a color change for a constant pattern or together with a change of the pattern in dependence on the viewing angle. The two relief-structured patterns can differ in particular in the shape of the pattern (for example head, apple or number), in the movement (static to moving or moving to static, with linear, rotational and/or pump-like movement) and/or in the dimensions (2D to 3D or differently three-dimensionally with a positive or negative camber appearance or suspended in front of or behind a plane).

The different height levels at which the two relief structures and the flat structures are arranged advantageously have a distance in the z-direction of between 5 μm and 100 μm, preferably between 10 μm and 50 μm. The small vertical distance of the participating structures is not perceptible when the security element is viewed. The base surface of the relief structure, for example at the base point of the micro mirror impressions, forms a reference point for the height level of the relief structure.

In an advantageous variant of the invention, the upper and/or lower color coating is designed as a regular or irregular grid with grid elements and grid gaps. The grid gaps present the abovementioned recesses of the respective color coating. In this variant, the dimensions of the grid elements and/or the grid gaps are below 140 μm at least in one direction. The dimensions of the grid elements and/or the grid gaps are preferably below 140 μm, preferably between 20 μm and 100 μm, in particular between 20 μm and 60 μm, even in one or both lateral directions.

In a further, likewise advantageous variant of the invention, the upper and/or lower color coating advantageously comprises a recess having a lateral dimension of more than 140 μm. The lateral dimension of the at least one recess is preferably greater than 250 μm, preferably greater than 500 μm and in particular greater than 1 mm.

The invention also encompasses a data carrier having an optically variable security element of the type mentioned, wherein the security element is arranged in or on a window region or a through-opening of the data carrier.

Finally, the invention also encompasses a method for producing an optically variable security element, preferably of the type described in detail above, wherein,

-providing a substrate, a face of the substrate extending defining a plane and a z-axis perpendicular to the plane,

-providing the substrate with multicoloured reflective surface areas comprising two relief structures which are arranged in different height levels in the z-direction and form an upper and a lower relief structure,

-providing the lower relief structure with a lower color coating following the relief course and providing the upper relief structure with an upper color coating following the relief course,

in the z-direction, a light-transmitting, colored flat structure is arranged on a height level between two relief structures, wherein the two relief structures and the flat structure are designed to overlap in an overlap region, and

the upper color coating is provided in the overlap region with at least one recess in which the lower relief structure emerges with a combined color effect of at least the translucent colored flat structure and the lower color coating when the security element is viewed from above, and

the lower color coating is provided in the overlap region with at least one recess, in which the upper relief structure emerges with a combined color effect of at least the translucent colored flat structure and the upper color coating when the security element is viewed from the underside.

In an advantageous method approach, two layer structures are produced separately, wherein the relief structures are produced on separate carriers and are assigned a corresponding color coating that follows the relief structures, and the two produced layer structures are laminated by means of a light-transmitting colored laminating lacquer layer, which in the laminated state forms the flat structure of the security element.

Further embodiments and advantages of the invention are explained below with reference to the drawings, which are not drawn to scale and are presented to scale in the figures in order to improve the intuitiveness.

In the drawings:

fig. 1 shows a schematic representation of a banknote with a transparent see-through window, on which an optically variable security element according to the invention is arranged,

figure 2 shows schematically in cross section a part of the security element of figure 1 applied to a banknote,

fig. 3 schematically shows an embodiment in which mutually overlapping recesses in the form of a dot grid are also provided next to the recesses arranged without overlapping, and

fig. 4 schematically illustrates another embodiment having blockwise spaced apart voids in the upper and lower color coatings.

The invention will now be illustrated by way of example of a security element for banknotes. To this end, fig. 1 shows a schematic representation of a banknote 10 having a transparent see-through window 12, on which an optically variable security element 14 according to the invention is arranged. The see-through window 12 can be formed, for example, by a transparent region of a plastic layer of the banknote 10 or by a through-opening in a paper layer of the banknote 10.

By arranging the security element in the see-through window, the security element 14 can be viewed from opposite sides, i.e. both from its upper side 16 and its lower side 18, and in this case each shows a different visual appearance.

The particular structure of the optically variable security element according to the invention will now be explained in detail with reference to fig. 2, fig. 2 schematically showing a section of the security element 14 applied to a banknote 10 in cross section.

The security element 14 defines with its face extension an x-y plane and a z-axis perpendicular to said x-y plane. The security element has, parallel to the x-y plane, surface regions 20 which, when viewed from the upper side 16, i.e. from the positive z-direction, and when viewed from the lower side 18, i.e. from the negative z-direction, each show a different, polychromatic reflective appearance. In the present exemplary embodiment, the security element 14 is applied with its underside 18 to the surface of a transparent plastic substrate by means of a transparent adhesive layer, not shown.

To create a different visual appearance, the panelsThe domain 20 comprises two

relief structures

24, 34 and a light-transmitting flat structure 44 arranged between the two relief structures. In particular, the

relief structures

24, 34 are arranged at a height level H_P1Or H_P2Upper and flat structure arranged at height level H_FWherein H is applied for the height class_P1＜H_F＜H_P2The relationship (2) of (c). The height classes of the different structures are described here from the underside of the security element 14, with which the security element is fastened to the banknote 10. Thus, the relief structure 24 near the lower side is referred to as a lower relief structure and the relief structure 34 near the upper side is referred to as an upper relief structure. The upper relief structure is closer to the viewer when viewed from the upper side of the banknote (viewing position 40) than the lower relief structure, and the relationship is reversed when viewed from the lower side of the banknote (viewing position 46), i.e. the lower relief structure is closer to the viewer than the upper relief structure.

In the present embodiment, the two relief structures represent micromirror imprints or

micromirror devices

24, 34, respectively, which are formed by a plurality of micromirrors inclined with respect to the x-y plane, respectively. The local tilt angles of the micromirrors are selected in such a way that the relief structures of the

micromirror devices

24, 34 each produce a desired optical appearance after color coating, for example a desired three-dimensional appearance or a desired movement effect when tilting the security element 14. The base or bottom points of the micromirrors of the micromirror device are respectively used as reference points for explaining the height level of the micromirror imprints.

The micro-mirror impressions are formed in the impression lacquer layer 22 or 23, respectively, wherein the impression lacquer layer 22 of the lower relief structure 24 is blue-tinted, while the impression lacquer layer 32 of the upper relief structure 34 is colorless and transparent. Furthermore, the

micromirror devices

24, 34 are each provided with a color coating, which is referred to as a lower color coating 26 or an upper color coating 36. In this embodiment, the two color coatings are each formed by an opaque aluminum layer. The lower and upper relief structures are flattened by a transparent

cover lacquer layer

28 or 38, respectively.

The two

color coatings

26, 36 each have a

recess

25, 35, which, despite the provision of the continuous micromirror imprints 24, 34, enables the observer to see the structures located below or above them in each case in partial regions. The

recesses

25, 35 are arranged in a staggered, but non-overlapping manner with respect to the x-y plane. This means that, within the surface extent of the surface region 20, the cutouts alternate a plurality of times in the upper and lower color coats, but are adapted to one another in such a way that, neither in a vertical view nor in an oblique view, a perspective through the entire surface region 20, i.e. through the cutouts 25 in the lower color coat 26 and also through the cutouts 35 in the upper color coat 36, is possible. In fact, the lower color coat 26 can be seen correspondingly in the cutout 35 of the upper color coat and, conversely, the upper color coat 36 can be seen correspondingly in the cutout 25 of the lower color coat.

In the present exemplary embodiment, the flat structure 44 is formed by a continuous, yellow-tinted laminating lacquer layer. Unlike the

relief structures

24, 34, the flat structure 44 is not designed to be structured in height. In the present embodiment, the two

micro-mirror devices

24, 34 and the colored flat structure 44 are arranged one above the other in the entire surface area 20 of the security element 14, so that the overlapping area occupies the entire surface area 20.

Due to the light-transmitting properties of the flat structure 44, the viewer can see the lower metallized

micro-mirror devices

24, 26 from the top (viewing position 40) through the upper micro-mirror device 34 and the flat structure 44 in the region of the recess 35. Therefore, when viewed from above, a color change from silver to yellow is formed to be shiny as a whole. In the region outside the hollow 35, the viewer observes the aluminum layer of the upper color coating 36, which produces a silvery shiny appearance (reference numeral 42-1). In the area of the recess 35, the observer sees the lower color coating 26 through the transparent embossing lacquer 32 and the flat structure 44, so that the color effect of the aluminum coating of the lower micromirror device 24 and the color effect of the yellow-tinted flat structure 44 combine there to a yellow-glowing appearance (reference sign 42-2). The transparent layers (topcoat 38, embossing lacquer layer 32, topcoat 28) do not change the color impression. The perspective through the entire surface area 20 cannot be achieved because the

cutouts

25 and 35 are arranged without overlapping.

When viewed from the underside (viewing position 46), the viewer can see the

upper micromirror devices

34, 36 through the blue-tinted lacquer of the lower micromirror device 24 and the flat structure 44 in the area of the recess 25. Therefore, when viewed from the lower side, a color change from blue to green is brightly formed as a whole. In the region outside the recess 25, the observer sees the aluminum layer of the lower color coating 26 through the blue-tinted embossing lacquer 22, which together produce a blue-shiny appearance (reference numeral 48-1). In the area of the recess 25, the observer sees the upper color coating 36 through the blue-tinted embossing lacquer 22 and the flat structure 44, so that the color effects of the aluminum layer of the upper micromirror device, the yellow-tinted flat structure 44 and the blue-tinted embossing lacquer 22 combine there to a green-shiny appearance (reference numeral 48-2). The transparent layers (covering lacquer layer 28, embossing lacquer layer 32) do not change the colour impression. Due to the non-overlapping arrangement of the

empty portions

25 and 35, the entire surface area 20 cannot be seen through from the lower side.

As already generally described above, the orientations of the micromirrors of the

micromirror devices

24, 34 are selected independently of one another, so that the security element 14 generally shows different patterns in addition to different color effects when viewed from the top side 16 and the bottom side 18. For example, a three-dimensionally outwardly curved value is visible when viewed from the upper side 16 (viewing position 40), and a three-dimensionally outwardly curved emblem is visible when viewed from the lower side 18 (viewing position 46). However, the patterns are adapted to one another in such a way that an overlap of the recesses 25 in the lower color coat (green-lit appearance on the underside) and the recesses 35 in the upper color coat (yellow-lit appearance on the upper side) is avoided.

In the embodiment of fig. 2, the appearance of four colors overall is produced by appropriate dyeing of the different layers involved, for which purpose in particular the embossing lacquer layer 22 of the lower relief structure 24 has been glossed. In an alternative embodiment, however, this embossing lacquer layer can also be designed to be transparent and colorless. Depending on the design of the

color coating

26, 36, the security element is thus bichromatic or quadrichromatic when viewed from the top and bottom.

Thus, the color effect is determined in this case by the color effect of the upper color coat 36 (outside the cutout 35) or by the color effect of the combination of the flat structure 44 and the lower color coat 26 (within the cutout 35) when viewed from the upper side 16, whereas the color effect is given by the color effect of the lower color coat 26 (outside the cutout 25) or by the color effect of the combination of the flat structure 44 and the upper color coat 36 (within the cutout 25) when viewed from the lower side 18. If the color effect of the

color coatings

26, 36 is the same, for example for two aluminum layers of the same type, dichroism is formed as a whole.

Conversely, if the color effects of the

color coatings

26, 36 are different, for example for a copper or gold layer on the one hand and an aluminum layer on the other hand, four different color impressions (metal 1, metal 1+ flat structure, metal 2+ flat structure) are formed when the security element is viewed from the top or bottom.

In a variant of the design of fig. 2, the overlap of the cutouts is not avoided, but rather an overlap is provided in a targeted manner in the see-through region, in which overlap the cutouts of the

color coatings

26, 36 overlap in order to achieve a see-through the entire surface region 20. The color effect of these see-through areas is determined by the combination of the color effects of the embossing paints 22 and 32 and the flat structure 44. The perspective region can in particular only allow perspective in oblique viewing angles, in order to provide additional authenticity safety.

The embodiment of fig. 3 schematically shows this design, wherein only the

color coating

26, 36 with the recesses and the flat structure 44 are shown for the sake of clarity. As already described in connection with fig. 2, a recess 35 is provided in the upper color coat 36, which recess 35 is located above the region of the lower color coat 26 that is not to be provided, and a recess 25 is provided in the lower color coat 26, which recess 25 is located below the region of the upper color coat 36 that is not to be provided. The visual effect which has been described above is thus formed by the

viewing directions

50 and 52.

In the see-through region 54, there are additionally provided cutouts 56 of the upper color coat 36 and cutouts 58 of the lower color coat 26, which are arranged aligned with one another, viewed in a predetermined oblique viewing direction 60, and which permit a see-through of the see-through surface region 20 in these oblique viewing directions 60. The

recesses

56, 58 are designed in the present exemplary embodiment in the form of a grid of small dots, which form a pattern, for example, in the form of a numerical value or a graphic. Since the dots are small (diameter below 1mm, or even below 300 μm), the voids are barely noticeable in perpendicular perspective or in reflected light viewing. When the security element 14 is viewed in transmitted light at a predetermined angle from the viewing direction 60, the pattern of the dot grid is only revealed by the transmitted light and disappears again when the security element is tilted by a few degrees from the viewing direction 60.

Fig. 4 shows a further exemplary embodiment of a security element 70, which is constructed substantially like the security element 14 from fig. 2. Unlike the security element of fig. 2, however, the

recesses

25, 35 of the

color coatings

26, 36 are not staggered but are separated in blocks. In particular, the security element 70 comprises a first block-shaped region 72 in which only the recesses 35 are present in the upper color coat 36, while the lower color coat 26 is designed to be continuous. In the second block-shaped region 74, only the recesses 25 are present in the lower color coat 26, while the upper color coat 36 is designed to be continuous.

In the block-shaped region 72, the security element 70, when viewed from the top, exhibits the above-described color change from silver to yellow in a luminous manner, whereas, when viewed from the bottom, the security element does not exhibit the color change but only exhibits the combined blue-luminous appearance of the embossing lacquer layer 22 and the continuous lower color coating 26.

In the block regions 74, the security element 70, when viewed from the underside, brightly displays the already described color change from blue to green, whereas, when viewed from the upper side, the security element does not display the color change but only the silver appearance of the continuous color coating 36.

List of reference numerals

10 banknote

12 perspective window

14 Security element

16 upper side

18 lower side

20 reflective face region

22 embossing lacquer layer

24 lower relief structure

25 space part

26 lower color coat

28 transparent cover paint layer

32 embossing lacquer layer

34 upper relief structure

35 hollow part

36 top color coat

38 transparent cover paint layer

40 observation position

42-1, 42-2, when viewed from the upper side

44 light-transmitting flat structure

46 observation position

48-1, 48-2 color change when viewed from the underside

50. 52 direction of view

54 region of perspective

56. 58 flush arranged space

60 oblique viewing direction

70 Security element

72 first block region

74 second bulk region

Claims

1. Optically variable security element for providing security to an item of value, which security element, when viewed from an upper side and an opposite lower side, each shows a different visual appearance, wherein,

-the face extension of the security element defines a z-axis extending perpendicular to said face,

the security element has a multicoloured reflective surface area,

the multicolored reflective surface regions comprise two relief structures which are arranged in the z-direction in different height levels and form an upper relief structure close to the upper side of the security element and a lower relief structure close to the lower side of the security element,

-the lower relief structure is provided with a lower color coating following the relief run and the upper relief structure is provided with an upper color coating following the relief run,

a light-transmissive, colored flat structure is arranged at a height level between the two relief structures in the z-direction, wherein the two relief structures and the flat structure overlap in an overlap region,

the upper color coating has at least one recess in the overlap region, in which recess the lower relief structure appears with a combined color effect of at least the translucent colored flat structure and the lower color coating when the security element is viewed from above, and

the lower color coating has at least one recess in the overlap region, in which the upper relief structure emerges with a combined color effect of at least the translucent colored flat structure and the upper color coating when the security element is viewed from the underside.

2. A security element according to claim 1, wherein the recesses in the upper colour coating and the recesses in the lower colour coating are arranged without overlapping.

3. A security element according to claim 1, characterized in that, in addition to the non-overlapping recesses in the upper and lower color coats, there are also recesses in both color coats that overlap one another, which from a viewing direction enable a perspective through the surface region.

4. A security element according to claim 3, characterized in that the mutually overlapping recesses are arranged in the form of a dot grid, which forms a marking, pattern or code.

5. Security element according to at least one of claims 1 to 4, characterized in that the recesses of the upper and lower color coating which are arranged without overlapping are arranged in a staggered manner.

6. A security element according to at least one of claims 1 to 5, characterized in that the recesses in the upper and lower color coating which are arranged without overlapping are arranged in a block-like manner at a distance from one another.

7. A security element according to at least one of claims 1 to 6, characterized in that the color effects of the relief structure, the color coating and the flat structure are adapted to one another such that, when viewed from the top, the security element exhibits a first color impression outside the cutouts of the upper color coating and a second color impression different from the first color impression inside the cutouts, and when viewed from the bottom, the security element exhibits a third color impression outside the cutouts of the lower color coating and a fourth color impression different from the third color impression inside the cutouts.

8. A security element as claimed in claim 7, characterized in that the color effects of the relief structure, the color coating and the flat structure are adapted to one another in such a way that all four color impressions are different from one another.

9. Security element according to at least one of claims 1 to 8, characterized in that the flat structure is formed by laminating a lacquer layer, a primer layer or a printed color layer.

10. Security element according to at least one of claims 1 to 9, characterized in that the flat structure contains dyed pigments and/or dyes as colorants.

11. Security element according to at least one of claims 1 to 10, characterized in that the upper and/or lower color coating is a reflective color coating, in particular a reflective, opaque color coating, and is preferably formed by a metallization, a lamellar structure, by a gloss color applied to the rear side by metallization, by a luminescent color with a metallic mirror surface, by a structural color and/or by a nanoparticle color.

12. Security element according to at least one of claims 1 to 11, characterized in that the upper and/or lower relief structure is/are formed in a transparent or a lustering embossing lacquer layer, in particular the upper relief structure is formed in a transparent embossing lacquer layer and the lower relief structure is formed in a lustering embossing lacquer layer.

13. Security element according to at least one of claims 1 to 12, characterized in that the upper relief structure and/or the lower relief structure is formed by a micromirror device with directional micromirrors, in particular by a micromirror device with non-diffractive mirrors, and preferably with plane mirrors, concave mirrors and/or fresnel-type mirrors.

14. Security element according to at least one of claims 1 to 13, characterized in that the orientation of the micromirrors of the upper and/or lower relief structure is changed in a position-dependent manner in order to produce a correspondingly predetermined pattern, in particular a three-dimensionally effective pattern or a movement pattern.

15. Data carrier having an optically variable security element according to at least one of claims 1 to 14, wherein the security element is arranged in or on a window region or a through-opening of the data carrier.

16. A method for producing an optically variable security element, preferably according to at least one of claims 1 to 14,

-providing the substrate with multicoloured reflective face regions comprising two relief structures arranged in different height levels in the z-direction and forming upper and lower relief structures,

17. The method according to claim 16, characterized in that the two layer structures are produced separately, wherein the relief structures are produced on separate carriers and are provided with a corresponding color coating following the relief course, and the two produced layer structures are laminated by means of a light-transmitting colored laminating lacquer layer, which in the laminated state forms the flat structure of the security element.