CN114103516B

CN114103516B - Optically variable security element, method for producing a security element and data carrier using said security element

Info

Publication number: CN114103516B
Application number: CN202110991674.2A
Authority: CN
Inventors: M.普费弗; K.H.谢勒; M.R.约翰; C.蒙格尔; H.莱希
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient GmbH
Priority date: 2020-08-27
Filing date: 2021-08-26
Publication date: 2023-03-14
Anticipated expiration: 2041-08-26
Also published as: EP3960481A1; DE102020005268A1; CN114103516A; EP3960481A8; EP3960481B1

Abstract

The invention relates to an optically variable security element for securing valuable articles, which has different visual appearances when viewed from the front and from the rear and displays a common perspective information. The security element comprises a security feature having a front surface with a translucent or transparent first surface area and an opaque second surface area, the first surface area having a higher permeability to cross-linking radiation, in particular UV radiation, than the second surface area, the two surface areas giving the visual appearance of the front surface. The security element comprises a rear optically variable security feature having a crosslinked effect layer with platelet-shaped, three-dimensionally oriented effect pigments, a first and a second face region, the effect layer being oriented in different ways, the two face regions giving rise to a different rear appearance. The first surface region of the front security feature is arranged congruent to the first surface region of the rear security feature, the two first surface regions generating a common perspective information.

Description

Optically variable security element, method for producing a security element and data carrier using said security element

Technical Field

The invention relates to an optically variable security element for securing valuable articles, which has a different visual appearance when viewed from the front and from the rear. The invention also relates to a method for producing such a security element and to a data carrier provided with such a security element.

Background

Data carriers, such as value documents or identity documents and other items of value, such as branded goods, are usually provided with security elements for security (or forgery) which allow the authenticity of the data carrier to be checked and at the same time serve as protection against unauthorized copying. Security elements with a viewing-angle-dependent or three-dimensional appearance play a special role in ensuring authenticity, since they cannot be reproduced even with the most modern copy machines. For this purpose, the security element is equipped with optically variable elements which provide the viewer with different image impressions at different viewing angles and, for example, display different color or brightness impressions and/or different graphic patterns depending on the viewing angle.

In recent years, authenticity features which can be viewed from opposite sides, for example in the see-through window of a banknote, have also become more attractive.

However, currently such authenticity features usually show the same appearance on both sides, or a combination of visually appealing effects are only visible on the front side and not on the back side. In part, completely unrelated appearances can also be seen on the front and back, so that the security function of the window feature hardly exceeds the function of two separate authenticity features. The known authenticity features therefore only insufficiently provide a security safeguard for one side, usually the rear side, of a banknote or other value document.

Disclosure of Invention

Starting from this point of view, the object of the invention is to provide a security element of the type described in the introduction which combines an attractive visual effect on both sides with high security against forgery.

The object is achieved by an optically variable security element for providing security to a value item, a method for producing such a security element, and a data carrier equipped with such a security element.

According to the invention, the security element of the type according to the invention not only has different visual appearances when viewed from the front side and the rear side, but also displays a common perspective information.

The security element is provided with a translucent or transparent first surface area

And a front-side security feature of an opaque second side area, wherein the first side area of the front-side security feature has a higher permeability to crosslinking radiation, in particular to UV (ultraviolet) radiation, than the second side area: (

Or transmissive) and wherein these two face regions produce the visual appearance of the front face of the security element.

The security element is furthermore provided with a rear-side optically variable security feature having a crosslinked effect layer with platelet-shaped, three-dimensionally oriented effect pigments (effect), and having a first and a second face region in which the effect pigments are oriented in different ways, and wherein these two face regions produce the appearance of different rear sides of the security element.

The first surface region of the front-side security feature is arranged congruent (deckungsgleich) to the first surface region of the rear-side security feature, the two first surface regions generating a common perspective information.

As explained in more detail below, this higher permeability of the first surface region to the crosslinking radiation allows the security features of the front side to be used as exposure masks for selective crosslinking and thus for hardening of the effect layer of the security element of the rear side, and thus for producing a different orientation of the effect pigments in the rear side element congruent with the front side element.

The crosslinking radiation is preferably UV radiation, but electron radiation or high-energy visible radiation in the blue or violet spectral range can also be used. A crosslinked effect layer refers to a layer that can be crosslinked, which is crosslinked and thus hardened by the action of crosslinking radiation.

Advantageously, the front-side security feature is likewise an optically variable security feature, and is preferably a micro-optical relief element, in particular having a hologram, a sub-optical structure, a micro-mirror device (mikrospiegeland) a micro-lens device, a micro-fresnel lens device, a moth-eye structure, a sub-wavelength structure or a combination of these elements.

When viewing the front side, the micro-optical relief may in particular show a colour change related to the tilt angle, a look-down-perspective colour change, a dynamic shading effect related to the tilt angle, a running/flipping effect, a stereo effect or a rainbow effect.

The micro-optical relief elements preferably comprise a reflective coating formed of a reflective metal (Reflektormetall), a color tilted (farckipend) thin layer element, a high refractive index layer, or a combination of these elements. The reflective metal may be formed, for example, of Al, cr, in, cu, of an alloy, or of a metallic pigment color. The color-gradient lamellar element has in particular the layer sequence: reflective/dielectric/absorptive structures (absorbers), in which the reflective layer may be composed of aluminum, the dielectric spacer layer of SiOx, and the absorptive structure layer of chromium. The high-refractive-index layer preferably has a refractive index of 1.8 or more, particularly 2.0 or more, and may be made of, for example, tiO ₂ Or ZnS formation.

Advantageously, the reflective coating contains recesses, which are formed in particular in the form of characters, text, numbers, symbols, decorations or combinations of these elements and produce translucent or transparent surface regions of the front-side security feature. The open areas of the reflective coating can also represent (or represent) pixels or partial pixels of a complex perspective image. In this case, a gray-scale transmission image (gray-scale transmission image) can be obtained by targeted local variation of the demetallized pixel density. The recess can be produced, for example, by cleaning, etching, laser or other methods known per se. In an embodiment of the invention, the recess can also be individualized, for example by digital printing of the cleaning/etching paint or laser demetallization.

In a visually attractive design, the reflective coating may in particular have a recess which represents a pixel or a part of a pixel of the pixel image. The first side region of the security feature on the back side has an orientation region congruent with the pixels or part of the pixels, so that the mentioned recesses together with the congruent orientation region produce a common perspective pixellated image. Such a see-through pixel image is only very difficult to see from the front and back in top view and forms a hidden authenticity feature which hardly spoils the appearance of the front or back.

The front-side security feature may also comprise a printed mask having a higher or lower permeability to cross-linking radiation, preferably UV radiation, regionally (or locally), for example a mask made of a regionally applied UV or electron beam absorber. For example, such a printed mask can be arranged on the rear side of the effect layer, so that the effect layer is only cured in regions when UV or electron beam radiation is applied from the mask side. In addition to absorber masks, watermarks or tissue regions in the form of electrotypes can also be used to transmit cross-linking radiation of different intensities regionally.

In an advantageous embodiment, the security features of the front side and the rear side are present on opposite sides of a carrier which is transparent or translucent at least in a common see-through region. The carrier can be perforated or contain transparent or translucent material regions.

The support can in particular be made of paper, plastic or a composite material made of paper and plastic. The carrier may also contain further per se known security features, such as watermarks, security fibers, security threads, security imprints, etc.

In the first surface region of the security feature on the rear side, the platelet-shaped effect pigments are preferably oriented so as to extend perpendicularly to the surface of the effect layer. The directional effect pigments act like standing blind slats, allowing perspective through this face area of the effect layer.

In the second surface region of the security feature of the rear side, the effect pigments can be oriented three-dimensionally in a specific direction, but also in a direction that varies constantly depending on the position. There may also be further area regions with locally different orientations. Advantageously, in the second face region, the effect layer appears substantially opaque due to the orientation of the effect pigments, which is different from the vertical line, and displays a three-dimensionally appearing appearance or produces a dynamic effect.

The effect pigments are advantageously formed by magnetically orientable magnetic pigments, with preference being given to using metallized pigments, in particular aluminum-or silver-coated pigments. Pigments with thin film coatings are also considered, above all pigments with a color gradient or aluminum pigments with a colored coating produced by a wet chemical precipitation process. Furthermore, it is also possible to use reflective metallic pigments, preferably aluminum pigments, with a color coating of a varnishing (lasierend), or pigments with micro-optically active surface reliefs, for example surface reliefs of holographic patterns, micromirror reliefs, microlens reliefs or matt structured reliefs.

The aspect ratio of the platelet-shaped effect pigments can be described by the diameter to thickness ratio, which describes the ratio of the maximum diameter to the minimum diameter of the pigment. The diameter here always extends through the center of gravity of the pigment. Spherical pigments have a constant diameter and therefore a diameter to thickness ratio of 1. Values greater than 1 indicate anisotropic pigment shapes, where the dimension of the pigment in a particular direction (the "longitudinal direction") is larger, usually even significantly larger than the dimension of the pigment in another direction (the "transverse direction"). The effect pigments according to the invention advantageously have a diameter to thickness ratio of more than 5. The maximum diameter of the platelet-shaped effect pigments is preferably between 1 μm and 150 μm, preferably between 2 μm and 50 μm. For example, the particles and pigments described in patent documents EP 1 689 586B1, WO 2010/069823 A1 and WO 2013/090983 A1 are considered platelet-like effect pigments.

Alternatively, the effect pigments can also be formed by pigments which can be oriented by means of other interaction fields, in particular electric fields.

In a preferred embodiment, the effect layer with platelet-shaped effect pigments has, at least in regions, a machine-readable feature substance in order to impart a machine-readable property to the security element. The machine-readable feature substance can be part of the effect pigment or of the carrier medium in which the effect pigment is dispersed. In particular, feature substances having luminescent, for example fluorescent or phosphorescent, IR (infrared) absorption properties and/or magnetic properties are considered here.

The front-side security element can also be provided with machine-readable properties. For example, the reflective coating may comprise a magnetic metal regionally. The embossing lacquer layer into which the relief is advantageously pressed can also be mixed with luminescent, IR-absorbing and/or magnetic features.

The security element may be applied as a security thread or as a thin film element (strip or patch) onto the target substrate. After application to the target substrate, the outer carrier film of the security element can be removed again or can remain on the target substrate. The security element can also be produced directly on the plastic substrate.

The invention also relates to a method for producing an optically variable security element of the described type, which has a different visual appearance when viewed from the front side and the rear side, respectively, and which displays a common perspective information. In the process, the first and second liquid phases are,

producing a security feature on the front side of the carrier, said security feature having a translucent or transparent first side region and an opaque second side region, wherein the first side region of the security feature on the front side has a higher permeability for crosslinking radiation, in particular UV radiation, than the second side region,

applying a crosslinkable effect layer having platelet-shaped, three-dimensionally orientable effect pigments on the rear side of a carrier,

the platelet-shaped effect pigments are oriented at least in the peripheral region of the first side region of the positive security feature by means of an external orientation field, preferably perpendicular to the substrate surface,

applying a cross-linking radiation, in particular UV radiation, to the cross-linkable effect layer with the oriented effect pigments through the security feature serving as the front side of the exposure mask, so that the cross-linkable effect layer is cross-linked only in the area diametrically opposite the first side area and the effect pigments are thereby fixed in their orientation there,

the platelet-shaped effect pigments outside the first surface region are oriented in different ways by means of an external orientation field, and

the crosslinkable effect layer with the differently oriented effect pigments is exposed to a crosslinking radiation, so that the crosslinkable effect layer is completely crosslinked and the differently oriented effect pigments are thus fixed in their orientation.

In an advantageous embodiment, the crosslinkable effect layer is a UV-crosslinkable effect layer which is loaded with UV radiation in each case for crosslinking or curing and thus for fixing the orientation of the effect pigments. Alternatively, the effect layer that can be crosslinked can also be a layer that can be crosslinked by electron beams or by high-energy visible radiation in the blue or violet spectral range, which layer is then correspondingly charged with electron beams or high-energy visible radiation for crosslinking or hardening and thus for fixing the orientation of the effect pigments, respectively.

In an advantageous variant of the method, the effect pigments are formed by magnetically orientable magnetic pigments, and the magnetic pigments are oriented by the magnetic field of a permanent magnet or an electromagnet. In principle, however, the effect pigments can also be formed by pigments which can be oriented by means of other interaction fields, for example electric fields.

In an advantageous method orientation, the effect pigments can be oriented in the peripheral region of the first surface region before the first-mentioned orientation, first parallel to the layer plane by means of an external orientation field. Similarly, the effect pigments can be oriented outside the first surface region before the second-mentioned orientation, advantageously first parallel to the layer plane by means of an external orientation field.

The invention also relates to a data carrier having a security element of the type described. The data carrier can be, in particular, a value document, for example a banknote, in particular a paper banknote, a polymer banknote or a film composite banknote, a stock certificate, a bond, a certificate, a coupon, a check, a high-value admission ticket, but also a document card, such as a credit card, bank card, cash card, authorization card, identification card or passport leaflet.

The security element can be a separate security element, for example a thin-film element, which is arranged in a transparent window area or through-opening of the data carrier. The security element can also be a component of the data carrier itself and, for example, comprise a transparent partial region of the data carrier, on the opposite main surface of which the front-side or rear-side security feature is arranged.

In an embodiment of the invention, the security element described contains a pattern (Motiv, or visual object), in particular a portrait and/or a denomination (or value), and the data carrier is provided with at least one further security element having a different type of appearance, which repeats the pattern of the first-mentioned security element. Such a further security element can be formed, for example, by a watermark, a security thread or a printing element. The multiple use of the same pattern in security elements with different appearances and preferably different production techniques achieves an additional strong security for the data carrier, which can nevertheless be easily verified by a layman.

Drawings

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

In the drawings:

fig. 1 (a) and 1 (b) show schematic representations of the front or back of a banknote having an optically variable security element according to the invention;

in order to illustrate the structure and production of the security element according to the invention, intermediate steps in the production are schematically illustrated in fig. 2 (a) to 2 (d) in cross-sectional views, and the finished security element is schematically illustrated in fig. 2 (e).

Detailed Description

The invention will now be illustrated by way of example of a security element for banknotes. Fig. 1 (a) and 1 (b) show a schematic view of a banknote 10 for this purpose, wherein fig. 1 (a) shows the front side of the banknote and fig. 1 (b) shows the rear side of the banknote. The banknote 10 is provided with a plurality of different security features and comprises, inter alia, a first printed element 12, a window security thread 16 partially embedded in the banknote paper 14, a watermark 18, a second printed element 20 and a film element 30 applied to the banknote paper 14 in the transparent window area.

The thin film element 30 comprises a micro-optical relief having metallised opaque face regions 32 which in this embodiment present a holographic portrait corresponding to the portrait presented by the watermark 18 and the second printing element 20. The membrane element 30 also comprises a substantially transparent face region 34 which is configured in the form of the denomination "20" of the banknote. The value is also represented by the first printing element 12 and a portion of the watermark 18. By using the same pattern (portrait, denomination) several times in security features (printing elements, watermarks, metallized film elements) produced using different technologies, a strong security protection of the banknote 10 is achieved, which can nevertheless be easily checked by laymen.

On the rear side shown in fig. 1 (b), the banknote paper 14 is provided with optically variable magnetic features 40 in the region of the rear side opposite the front film element 30, said magnetic features showing an impressive three-dimensional appearance which is produced in the manner described in more detail below by the effect layer with platelet-shaped magnetic pigments. In the present embodiment, the magnetic feature 40 specifically comprises three

face regions

42, 44, 46 having different orientations of platelet-shaped magnetic pigment, and correspondingly three face regions having different appearances.

Of particular importance here is a first surface area 42, which is formed congruent with the substantially transparent surface area 34 of the foil element 30 in the transparent window area of the banknote paper 14 and therefore likewise in the form of the denomination "20". In this face region 42, the magnetic pigments are oriented substantially perpendicular to the substrate surface and thus allow viewing through the colored effect layer of the magnetic feature 40. The first face region 42 of the magnetic feature 40 on the rear side and the transparent face region 34 of the film element 30 on the front side thus produce the same perspective information in the form of the denomination "20" in the banknote 10.

In the

further surface regions

44, 46 of the magnetic feature 40, the magnetic pigments have respectively different spatial orientations. For example, the magnetic pigments are oriented parallel to the substrate surface in the region 46 having the euro-symbol shape and are oriented rotationally symmetrically in the star-shaped region 44 with an inclination to the vertical which increases from the center to the edge. When the back is viewed, the

face regions

44, 46 appear opaque and have the appearance of a sparkling three-dimensional presentation.

The thin-film element 30 and the magnetic feature 40 together with the part of the banknote substrate 14 lying between them form an optically variable security element according to the invention in the banknote 10, which security element has a different visual appearance and common perspective information when viewed from the front and back, respectively.

The structure and production of the optically variable security element according to the invention will now be explained in detail with reference to fig. 2 (a) to 2 (e), in fig. 2 (e) a finished security element 50 according to an embodiment of the invention is schematically illustrated in cross-section and in fig. 2 (a) to 2 (d) intermediate steps in the production of the security element are illustrated.

Referring first to fig. 2 (a), a micro-optical relief 54 is applied to a transparent region of the substrate 52, which in this embodiment is comprised of an embossing lacquer layer 56 having the desired holographic relief and a reflective opaque metal coating 58. The metal coating 58 is provided with a recess 60 in the form of the desired perspective information.

The recesses 60 of the metal coating 58 form not only visually transparent regions in the micro-optical relief 54, but also UV-transparent regions in the remaining UV-impermeable metal coating.

The effect layer 62 is applied to the opposite side of the substrate 52 in a printing process, preferably screen printing, and is composed of a curable (crosslinkable) carrier medium 64, in which effect pigments are dispersed, and magnetically orientable platelet-shaped effect pigments 66, as shown in fig. 2 (a).

The effect pigments 66 are then oriented perpendicular to the substrate surface in the not yet hardened state of the effect layer 62 by means of the magnets 70 at least in the peripheral region of the cutouts 60 of the metal coating 58, so that the effect pigments 68 are present there in a state oriented orthogonally to the substrate plane, as shown in fig. 2 (b).

The effect layer 62 with the oriented effect pigments 68 is then loaded with UV radiation 72 of a UV light source 74 from the opposite side through the micro-optical relief 54, as shown in fig. 2 (c). Since the micro-optical relief 54 is transparent to UV radiation only in the recess 60, the effect layer 62 is hardened by cross-linking only in the region 76 congruent with the recess 60, as is indicated by cross-hatching in the drawing. After this exposure step, the effect pigments 68 in the areas 76 are fixed in their vertical orientation, while the effect pigments 66 located outside the areas 76 are also movable.

Referring to fig. 2 (d), the still-movable effect paint is now placed into a different orientation using at least one additional magnet 78. For a simpler illustration, effect pigments 80 having an orientation parallel to the substrate plane are shown in the drawing, but it goes without saying that the effect pigments can also be oriented differently depending on the desired appearance, for example in one or more oblique directions, or also in directions which vary continuously depending on the position. It is also possible to produce different orientations with different appearances regionally, for example the

face regions

44, 46 of fig. 1 (b). However, the effect pigments 68 of the partial region 76 are already fixed in their orientation and therefore do not participate in this reorientation by the magnet 78.

In this oriented state of the effect pigments 80, the effect layer 62 is again exposed to UV radiation from a further UV light source, not shown, from the side of the effect layer 62 and is now completely hardened.

In this way, the security element 50 shown in fig. 2 (e) is formed, in the effect layer 62 of which the effect pigments 68, 80 have different fixed orientations regionally. One of the differently oriented regions is arranged congruent with the recess 60 of the opposite metal coating 58.

To the viewer, the platelet-shaped effect pigments of the effect layer 62 act like slats of a blind, which depending on the tilt position allow perspective or completely or partially block perspective. Currently, due to the orthogonal orientation of the effect pigments 68, the effect layer 62 is light-transmissive in the region 76, while it appears substantially opaque in the other face regions having a different orientation of the effect pigments 80.

In general, the micro-optical relief 54 produced forms a positive optically variable security feature having transparent surface regions in the form of recesses 60 and opaque surface regions with reflective opaque metallisation 58. The two face regions produce the visual appearance of the front face of the security element 50, for example a portrait and a denomination in the form shown in fig. 1 (a). In other, particularly visually attractive designs, the recesses 60 of the micro-optical relief 54 form fine pixels of a see-through image which is only visible in perspective and cannot be recognized from the front and back of the security element and thus forms a hidden message in the security element.

Effect layer 62 forms a back-side optically variable security feature with effect pigments 66, 80, effect pigments 66, 80 being oriented differently in different face regions. The different surface regions produce the appearance of different backs of the security element, for example the star-shaped regions 44 in fig. 1 (b) with the included face value 42 and euro symbol 46.

The recesses 60 in the front-side security feature and the front regions 76 of the rear-side security feature are arranged congruent to one another and produce a common perspective information in their shape. If the recess 60 represents a pixel image at least in one partial region, the area 76 is also designed as a corresponding pixel image in the partial region, so that, when viewed in perspective through the congruent arrangement of the recess 60 and the area 76, a desired pixel transmission image is formed as a hidden feature.

In an extended method orientation, referring to fig. 2 (b), effect pigments 66 may first be oriented parallel to the surface of substrate 52 by an additional magnetic field before being oriented by magnets 70, so as to have a defined starting condition for further orientation. Similarly, referring to fig. 2 (d), the effect pigments 80 may first be oriented parallel to the surface of the substrate 52 by an additional magnetic field before being oriented by the magnets 78, and only then the desired three-dimensional orientation is performed.

List of reference numerals

10. Banknote

12. Printing element

14. Banknote paper

16. Window security thread

18. Watermarking

20. Second printing element

30. Thin-film element

32 metallized, opaque face regions

34. Transparent panel area

40. Magnetic characteristics

42. 44, 46 face areas

50. Security element

52. Substrate

54. Micro-optical relief

56. Embossing lacquer layer

58. Metal coating

60. Hollow part

62. Effect layer

64. Carrier medium

66. Effect pigments

68. Orthogonally oriented effect pigments

70. Magnet body

72 UV radiation

74 UV light source

76. Hardened zone

78. Additional magnet

80. Oriented effect pigments

Claims

1. Optically variable security element for providing security to an item of value, which security element has a different visual appearance when viewed from the front and from the rear and displays a common perspective, comprising

-a security feature of a front side having a translucent or transparent first side area and an opaque second side area, wherein the first side area of the security feature of the front side has a higher permeability to cross-linking radiation than the second side area, and wherein the two side areas produce the visual appearance of the front side of the security element,

-an optically variable rear-side security feature having a crosslinked effect layer with platelet-shaped, three-dimensionally oriented effect pigments, the rear-side security feature further having a first and a second face region in which the effect pigments are oriented in different ways, and wherein the first and the second face region of the rear-side security feature produce different rear-side appearances of the security element,

-wherein the first face area of the front-side security feature is arranged congruent to the first face area of the rear-side security feature, and the two first face areas produce a common perspective information.

2. Security element according to claim 1, characterized in that the cross-linking radiation is UV radiation.

3. A security element as claimed in claim 1 wherein the security feature of the front surface is an optically variable security feature.

4. A security element according to claim 3, wherein the security feature of the front face is a micro-optical relief element.

5. A security element according to claim 4, wherein the micro-optical relief element has a hologram, a matt structure, a micro-mirror device, a micro-lens device, a micro-Fresnel lens device, a moth-eye structure, a sub-wavelength structure or a combination of these elements.

6. A security element according to claim 4, wherein the micro-optical relief element comprises a reflective coating formed from a reflective metal, a colour-gradient thin layer element, a high refractive index layer or a combination of these elements.

7. A security element as claimed in claim 6 wherein the reflective coating has a void.

8. A security element as claimed in claim 7 wherein the void is formed in the form of a character, text, number, symbol, decoration or a combination of these elements and creates a first face region of the front-face security feature.

9. A security element as claimed in claim 6 wherein the reflective coating has voids representing pixels or part-pixels of a pixellated image and the first face region of the security feature on the back has an orientation region congruent with these pixels or part-pixels, so that the mentioned voids together with the congruent orientation region produce a common see-through pixellated image.

10. A security element as claimed in claim 1, characterized in that the front-side and rear-side security features are present on opposite sides of a carrier which is transparent or translucent at least in a common see-through region.

11. A security element as claimed in claim 1, characterized in that the platelet-shaped effect pigments are oriented in the first surface region of the rear security feature extending perpendicularly to the surface of the effect layer.

12. A security element according to claim 1, characterized in that the effect pigments are formed by magnetic pigments which can be magnetically oriented.

13. A security element as claimed in claim 1, characterized in that the effect layer with platelet-shaped effect pigments has, at least regionally, a machine-readable feature substance in order to impart a machine-readable property to the security element.

14. A security element according to claim 10, characterized in that the carrier consists of paper, plastic or a composite material made of paper and plastic.

15. A method for producing an optically variable security element according to one of claims 1 to 14, which has different visual appearances when viewed from the front side and the rear side, respectively, and displays common perspective information, wherein,

-producing a security feature on the front side of the carrier having a translucent or transparent first side area and an opaque second side area, wherein the first side area of the security feature of the front side has a higher permeability to cross-linking radiation than the second side area,

applying a crosslinkable effect layer having platelet-shaped, three-dimensionally orientable effect pigments on the rear side of a carrier in order to produce a rear-side security feature having a first and a second side region, wherein the first side region of the front-side security feature is arranged congruent to the first side region of the rear-side security feature,

the platelet-shaped effect pigments are oriented at least in the first side region of the rear security feature by means of an external orientation field,

-applying a cross-linking radiation to the cross-linkable effect layer with the oriented effect pigments through the security feature of the front side used as exposure mask, so that the cross-linkable effect layer is cross-linked only in the first side region of the security feature of the rear side and the effect pigments are thereby fixed in their orientation there,

the platelet-shaped effect pigments outside the first surface region of the security feature on the rear side are oriented in different ways by means of an external orientation field, and

the effect layer which can be cross-linked and which has effect pigments oriented in different ways is subjected to a cross-linking radiation, so that the cross-linkable effect layer is completely cross-linked and the effect pigments oriented in different ways are thus fixed in their orientation.

16. The method according to claim 15, characterized in that the crosslinking radiation is UV radiation.

17. The method according to claim 15, wherein the platelet-shaped effect pigments are oriented perpendicularly to the substrate surface in the first side region of the rear security feature by means of an external orientation field.

18. The method according to claim 15, characterized in that the effect pigments are formed by magnetically orientable magnetic pigments and the magnetic pigments are oriented by the magnetic field of permanent magnets or electromagnets.

19. A data carrier having a security element according to any one of claims 1 to 14.

20. A data carrier as claimed in claim 19, characterized in that the security element is a separate security element which is arranged in a transparent window area or through-opening of the data carrier.

21. A data carrier as claimed in claim 19, characterized in that the security element forms an integral part of the data carrier itself.

22. A data carrier as claimed in claim 19, characterized in that the security element contains a pattern and the data carrier is provided with at least one further security element having a different type of appearance, containing the same pattern.

23. A data carrier as claimed in claim 22, characterized in that the pattern is a portrait and/or a denomination.