DE102011116494A1 - Method for producing an optically variable security element with microcapsule-based ink layer - Google Patents

Abstract

The invention relates to a method for producing an optically variable security element (14) with a microcapsule-based ink layer (34) in which U) a substrate layer (30, 32) is applied to a substrate F) a microcapsule-based ink layer (34) on the substrate layer ( 30, 32) containing in a binder a plurality of microcapsules (36) each comprising a capsule shell (38), a carrier liquid (40) enclosed in the capsule shell and a magnetically alignable platelet pigment (42; 60; 82 M) an external magnetic field (62) is applied to the rotatable pigments (42; 60; 82) at least in aligning a portion of the ink layer (34) in the microcapsules (36), and L) in the aligned pigment portion (60) by laser irradiation (64) with a Marki At least a portion (92) of the pigments and / or at least a portion (68; 94) of the background layer is modified.

Description

The invention relates to a method for producing an optically variable security element with microcapsule-based ink layer. The invention further relates to a security arrangement with such a security element and a correspondingly equipped data carrier.

Data carriers, such as valuables or identity documents, but also other valuables, such as branded goods, are often provided with security elements for the purpose of security, which permit verification of the authenticity of the data carrier and at the same time serve as protection against unauthorized reproduction. The security elements can be embodied, for example, in the form of a security thread embedded in a banknote, a covering film for a banknote with a hole, an applied security strip, a self-supporting transfer element or else in the form of a feature area printed directly on a value document.

A special role in the authenticity assurance play security elements, the viewing angle-dependent visual effects show, as they can not be reproduced even with the latest copiers. For some time, encapsulated magnetically orientable effect pigments have been used for this purpose, which can be magnetically aligned in the form of a motif to be displayed.

Proceeding from this, the object of the invention is to specify a method for producing optically variable security elements with a microcapsule-based ink layer, with which it is possible to produce such security elements with an attractive visual appearance and high security against counterfeiting.

This object is solved by the features of the independent claims. Further developments of the invention are the subject of the dependent claims.

• U) eine Untergrundschicht auf ein Substrat aufgebracht wird
• F) eine mikrokapselbasierte Farbschicht auf die Untergrundschicht aufgebracht wird, die in einem Bindemittel eine Vielzahl von Mikrokapseln enthält, die jeweils eine Kapselhülle, eine in der Kapselhülle eingeschlossene Trägerflüssigkeit und ein magnetisch ausrichtbares, plättchenförmiges Pigment aufweisen, welches in der Mikrokapsel im Wesentlichen frei drehbar und durch ein externes Magnetfeld reversibel ausrichtbar ist,
• M) ein externes Magnetfeld angelegt wird, um die drehbaren Pigmente zumindest in einem Teilbereich der Farbschicht in den Mikrokapseln auszurichten, und
• L) in dem Teilbereich mit den ausgerichteten Pigmenten durch Laserbeaufschlagung mit einem Markierungslaser zumindest ein Teil der Pigmente und/oder zumindest ein Teilbereich der Untergrundschicht modifiziert wird.

According to the invention, it is provided in a method for producing an optically variable security element with a microcapsule-based ink layer

• U) a substrate layer is applied to a substrate
• F) a microcapsule-based ink layer is applied to the background layer containing in a binder a plurality of microcapsules each having a capsule shell, a carrier liquid enclosed in the capsule shell and a magnetizable platelet-shaped pigment which is substantially freely rotatable within the microcapsule and reversibly alignable by an external magnetic field,
• M) an external magnetic field is applied to align the rotatable pigments at least in a portion of the color layer in the microcapsules, and
• L) in the partial area with the aligned pigments by laser irradiation with a marking laser at least a portion of the pigments and / or at least a portion of the background layer is modified.

In this case, each laser-induced, visually visible or machine detectable change in the pigments or the background layer is a modification. Typically, the modification consists in a change in the color, brightness or reflection behavior (glossy / matt) of the pigments or the background layer. For the changes that can be detected by machine, it may, for. B. be changes that are detectable only in the infrared or ultraviolet wavelength range. Modifications of the pigments or of the background layer, which can only be detected by machine, are characterized by the fact that they provide high protection against counterfeiting for the modified security element, whereby the authenticity check of such a security element can be reliably carried out by suitable means for automatic detection.

In an advantageous variant of the method, a laser-modifiable background layer is applied in step U), preferably a background layer with infrared-absorbing inks and / or metal layers. In step L), at least a portion of the background layer is then advantageously modified by laser application, in particular destroyed or bleached. In particular, the modification of the background layer can contrast the contrast between a transparent state of the microcapsule-based ink layer, in which the pigments are oriented perpendicular to the plane of the ink layer, and a non-transparent state of the microcapsule-based ink layer, in which the pigments are aligned parallel to the plane of the ink layer , be increased significantly, as shown in detail below.

If both the pigments and the background layer are modified by laser application, in particular a motif can be introduced into the background layer and the color layer at the same time and with registration accuracy. If only the pigments are modified, it is possible in particular for a motif to be introduced into the ink layer which is only visible in certain orientations of the pigments.

According to an expedient embodiment, a microcapsule-based ink layer is applied in step F), whose ptättchenförmigen pigments are reflective for the wavelength of the marking laser. The reflective pigments can be formed in particular by oxidic multilayer interference layer pigments.

According to another, likewise expedient embodiment, a microcapsule-based ink layer is applied in step F), the platelet-shaped pigments of which are laser-modifiable with the marking laser. The laser-modifiable pigments can be formed in particular by multilayer interference pigments with metallic layers.

The encapsulated pigments are preferably platelet-shaped, with the ratio of the largest to the smallest diameter (diameter-to-thickness ratio) of the platelet-shaped pigments being more than 4: 1, preferably more than 10: 1, and more preferably between 20: 1 and 200: 1 lies. The largest diameter of the platelet-shaped pigments is preferably between 2 μm and 150 μm, in particular between 5 μm and 50 μm.

According to a further, likewise expedient embodiment, a microcapsule-based ink layer is applied in step F), the binder of which contains particles which have a scattering or absorbing effect at the wavelength of the marking laser. The scattering or absorbing particles may in particular be formed by titanium dioxide or iron oxide particles. In the visible spectral range, the particles are preferably inconspicuous.

In all embodiments, the microcapsule-based ink layer is advantageously applied by screen printing or flexographic printing. The microcapsules themselves have a diameter between 1 .mu.m and 200 .mu.m, preferably between 2 .mu.m and 80 .mu.m. It is understood that the diameter of the microcapsules is advantageously matched to the size of the encapsulated pigments. The wall thickness of the microcapsules is typically between 2% and 30%, preferably between 5% and 15% of the diameter of the microcapsules.

Advantageously, in step M), the pigments are aligned at least in a partial region of the ink layer perpendicular to the loading direction of the marking laser in step L). As a result, a particularly high level of interaction between laser radiation and pigments is achieved in this area. Also advantageously in step M), the pigments are aligned parallel to the direction of loading of the marking laser in step L), at least in a partial region of the ink layer. As a result, a particularly high permeability of the color layer for the laser radiation is achieved in this area and thus enables a high level of interaction between the laser radiation and the background layer.

In advantageous embodiments, the pigments in step M) are aligned differently in different subregions of the ink layer, so that different effects in the different subregions can be generated simultaneously by the laser application.

Of course, the microcapsules may each contain a plurality of pigments, for example a magnetically alignable and an optically variable pigment. It can be used in a security element and encapsulated pigments with different properties, in particular different magnetic properties or different interaction strength with the radiation used, so that by different strong radiation or by the different properties of the pigments first and second information can be introduced into the security element.

The laser application can be made over the entire surface, so that the different influence of pigments and background layer is only produced by the magnetic orientation of the pigments. In some embodiments, however, it may be advantageous if the laser application in step L) takes place in a subarea in the form of patterns, characters or an encoding. In this case, the radiation itself can be over the entire surface and the subregion can be selected by means of a suitable mask with predetermined regions permeable to the radiation. Alternatively, a suitably focused beam in the form of the portion to be modified can be guided over the security element.

In all embodiments, the background layer in step U) is advantageously applied in the form of information, in particular a pattern, a character or a coding. Suitable application methods for the background layer are, in particular, screen printing, flexographic printing or intaglio printing.

For the laser application in step L), an infrared laser is preferably used as the marking laser, preferably an infrared laser in the wavelength range from 0.8 μm to 3 μm, such as an Nd: YAG laser or Nd: YVO ₄ laser. Preferably pulsed marking lasers are used. The laser parameters, in particular wavelength, power density, pulse duration and exposure time, and the materials of pigments and substrate are suitably matched to one another depending on the desired modification (only pigments, only background layer or both).

The invention also includes a security arrangement for securing security papers, value documents and the like, with a security Security element, which can be produced by a method described above, and with a verification element with a magnetic region. Magnetic material advantageously has magnetic material in the form of patterns, lines, characters or a coding. The motif represented by the magnetic material can be openly visible to a viewer or hidden even without aids, for example by covering with a dark printing layer. Preferably, the magnetic region is magnetized substantially perpendicular to the plane of the verification element.

The invention further comprises a data carrier, in particular a value document, such as a banknote, a passport, a document, an identification card or the like, which is equipped with a security element that can be produced according to a method described above or with a security arrangement of the type described. If the data carrier contains both a security element according to the invention and an associated verification element, these are advantageously geometrically arranged on the data carrier such that the security element can be brought over the verification element by bending or folding the data carrier.

Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation true to scale and proportion has been dispensed with in order to increase the clarity.

Show it:

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

2 a cross-section through a security element with a reversible change of the visual appearance, in the left half without and in the right half with verification device,

3 an intermediate step in the production of a security element with a method according to the invention,

4 in (a) and (b) the appearance of the background layer of the security element of 3 before the laser application and in (c) and (d) after the laser application,

5 in (a) to (c) a further embodiment of the invention, in which by the magnetic field-induced change in transparency, a subject is introduced simultaneously and precisely in both the background layer and in the ink layer, and

6 in (a) to (e), another embodiment of the invention, in which a motif is introduced only in the microcapsule-based ink layer.

The invention will now be explained using the example of security elements for banknotes and other value documents. 1 shows a schematic representation of a banknote 10 with a directly on the banknote paper 12 printed, optically variable security element 14 with an interactive triggering authenticity mark 16 , However, the invention is not limited to printed security elements and banknotes, but can be used in all types of security elements, such as labels on goods and packaging or in the security of documents, ID cards, passports, and the like.

In particular, the invention may also be applied to cards such as identity cards, bank cards, credit cards, health cards or driver's licenses. In addition to printed elements, for example, transfer elements, security threads or security strips and also supervisory elements in addition to supervisory elements in question.

Coming back to the presentation of the 1 contains the security element 14 a reversible, by a magnetic verification device ( 2 ) interactive triggerable authenticity mark. Without Verification device shows the security element 14 a uniform appearance, such as a metallic luster. Becomes the security element 14 placed on the magnetic verification device by a user, so does the visual appearance of the security element 14 changed interactively and reversibly. In the embodiment, the metallic luster of the security element disappears 14 when placed on the verification device and an information-bearing background layer 16 with the denomination "5" of the banknote becomes visible as in 1 shown in dashed lines. Removes the user from the security element 14 again from the verification device 20 , after a short time the uniform initial state is restored, in which the background layer 16 is hidden from the viewer.

The structure of the security element 14 and the occurrence of the reversible change of the visual appearance will now be described with reference to the cross-sectional view of FIG 2 explained in more detail. The left half of the figure shows the security element 14 without verification device 20 or an area 28 away from the magnet 20 while the right half of an area 26 of the security element that is directly above the magnet 20 located.

On the banknote paper 12 the banknote 10 is in the area of the security element 14 a background layer 30 applied any information, such as a representation of the denomination "5" of the banknote 10 , may contain. The background layer 30 can consist of one or more colors and is typically applied in offset, letter set, flexographic or intaglio printing.

About this background layer 30 is a screen printing process under normal conditions largely opaque, microcapsule-based ink layer 34 applied. The color layer 34 contains a variety of microcapsules 36 , each containing a capsule shell 38 , one in the capsule shell 38 enclosed carrier liquid 40 and at least one platelet-shaped, magnetically alignable pigment 42 exhibit. The pigments 42 are in the microcapsules 36 essentially freely rotatable and can be driven by an external magnetic field, such as the field 22 of the magnet 20 , be aligned reversibly.

In the embodiment shown are the pigments 42 platelet-shaped iron pigments prepared from reducing treated carbonyl iron powder with a high platelet diameter to platelet thickness ratio of 20: 1 or more. The (largest) platelet diameter is preferably between 2 μm and 150 μm, in particular between 5 μm and 50 μm, and the platelet thickness is preferably between 40 nm and 1.5 μm, in particular between 200 nm and 1.3 μm.

Depending on the intended application, the pigments 42 be formed one or more layers and in the latter case, in addition to at least one magnetic layer also have at least one non-magnetic layer. For example, oxide multilayer interference pigments can be used as laser radiation-reflecting pigments, and multilayered interference pigments with metal layers can be used as laser radiation absorbing pigments.

Because the pigments 42 in the carrier liquid 40 inside the capsule shell 38 are essentially freely rotatable, they have no preferential orientation without external magnetic field, but rather are essentially random and thus aligned isotropically as a whole. The even distribution of the orientation of the pigments 42 in all directions is in the left half of the 2 shown schematically.

In the area 26 immediately above the magnet 20 become the magnetically orientable pigments 42 however, due to their free rotation in the capsule shell 38 magnetically aligned. The platelet-shaped pigments 42 orient themselves with their platelet expansion along the magnetic field lines 22 , At the in 2 shown situation, the magnetic field lines occur 22 in the area 26 essentially perpendicular through the paint layer 34 through and direct the pigments 42 thus also substantially perpendicular to the plane of the color layer 34 off (right half of the picture) 2 ).

Because of their platelike shape, the pigments act 42 for the beholder, like the slats of a blind, which overlooks the underlying underlying layer 30 release or completely or partially block. In the fields of 28 in which the pigments 42 essentially isotropic in its capsule shells 38 are arranged (left half of the 2 ), they limit the view of the underground layer 30 strong one that the color coat 34 in this area depending on the concentration of microcapsules 36 appears largely opaque and the metallic luster of the pigments 42 the visual impression of the security element 14 dominated.

In the area 26 in which the pigments 42 through the magnet 20 substantially perpendicular to the plane of the paint layer 34 aligned, they give, in contrast to the slats of a blind set parallel, the view of the underlying background layer 30 and the representation of the denomination "5" free. Because of the large ratio of platelet diameter to platelet thickness of 20: 1 or more, there is a high contrast between opaque portions 28 and translucent subregions 26 , In addition, this appears through the wafer alignment in the subregions 26 . 28 created motif for the human eye with an effective, three-dimensional appearing appearance.

Becomes the security element 14 again from the magnet 20 removed, so relax the magnetically oriented pigments 42 due to their mobility within the capsule shell 38 after some time back into the essentially isotropic initial state of the left half of the picture 2 , The change in the visual appearance of the security element 14 is thus triggered interactively and is completely reversible. The speed with which the pigments 42 can return to their initial state, for example, by the viscosity of the carrier liquid 40 be set as desired within a wide range.

2 illustrates the change in visual appearance when looking at a finished security item 14 , However, the present inventors have surprisingly found that there is a magnetic alignment of the platelet-shaped pigments 42 even in the production of security elements with microcapsule-based ink layer can be used advantageously.

The invention uses in the observation that a microcapsule-based ink layer 34 defined by an external magnetic field of a transparent state in which the pigments 42 are aligned perpendicular to the plane of the ink layer (right half of the 2 , Magnetic field perpendicular to the color layer plane) can be converted into a non-transparent state in which the pigments 42 aligned parallel to the plane of the ink layer (magnetic field parallel to the color layer plane). This property can be exploited to help in the manufacturing process of the security element 14 by laser application of magnetically oriented areas targeted the background layer 30 (in the transparent state of the color layer 34 ) and / or the pigments 42 itself (in the non-transparent state of the color layer 34 ) to modify.

In a first embodiment, with reference to the 3 and 4 is described, allows the magnetic field-induced transparency change to significantly increase the contrast of interactively representable information.

First shows 4 (a) the appearance 50 a background layer 30 a security element 14 with printed information 32 in the form of the letter "a" in the transparent state of the color layer 34 , The pigments 42 are in it in the microcapsules 36 perpendicular to the color layer 34 aligned and give the view of the information 32 unhindered free.

Be the pigments 42 in the microcapsules 36 now aligned by a magnetic field parallel to the color layer plane, so block the microcapsules 36 largely the view of the underground layer 30 , as in 4 (b) shown schematically. However, there is usually even with highly pigmented layers of paint 34 individual jobs 54 where no microcapsules 36 available. Even in the non-transparent state of the color layer 34 can thus in the appearance 52 of the security element yet a rest 56 the information 32 be visible.

For the information 32 with particularly high contrast between transparent and non-transparent microcapsule state, with reference to 3 According to the invention, first a laser-modifiable background layer 30 with the desired information 32 on the substrate 12 applied. The laser modifiability of the background layer 30 For example, it may be that the information 32 is printed with an infrared-absorbing ink, which can be destroyed or bleached, for example, by the infrared radiation of a used as a marking laser Nd: YAG laser.

On this laser-modifiable background layer 30 becomes a microcapsule-based color coat 34 applied in a binder a variety of microcapsules 36 with platelet-shaped, magnetically orientable pigments 60 which are highly reflective at the wavelength of the Nd: YAG marker laser.

Then an external magnetic field 62 put on the pigments 60 parallel to the plane of the color layer 34 aligns. In the aligned state of the pigments 60 become the underground layer 30 and the color layer 34 with laser radiation 64 an Nd: YAG laser marking, wherein the laser parameters, in particular power density, pulse duration and exposure time, are selected so that the highly reflective pigments 60 even by the laser radiation 64 not be changed, but that they are the irradiated laser light 64 reflect as much as possible (reference numeral 66 ). Outside the microcapsules 36 the laser radiation penetrates 64 however, except for the laser-modifiable background layer 30 before and destroyed in the affected areas 68 the infrared-absorbing ink of the information 32 ,

This results in the non-transparent state of the color layer 34 this in 4 (c) illustrated appearance 70 in which the information 32 straight into the outside of the microcapsules 36 lying areas 68 is removed. In the non-transparent state of the color layer 34 is thus no or virtually no rest of the information 32 more visible. The destroyed areas 68 the information 32 Although missing in the appearance 72 the background layer 30 in the transparent state of the color layer 34 , as in 4 (d) shown, but lead in practice only to a slight whitening of the information shown 32 ,

By contrast, the contrast between transparent and non-transparent state is significantly increased by the described measure. Are for example after the application of background layer 30 and color layer 34 in non-transparent state still 5% of the information 32 visible (situation of 4 (b) ), so can the contrast between the transparent and non-transparent state with K _before = 100% / 5% = 20 be specified. Be by the laser irradiation then 4/5 of the affected areas 68 ie 4% -points related to the original information 32 destroyed, only 1% of the original information is visible in the non-transparent state (situation of 4 (c) ) and in the transparent state still 96% of the original Information visible (situation of 4 (d) ). The contrast after laser exposure has thus increased K _to = 96% / 1% = 96, So almost increased by a factor of 5. This increase in contrast is much more important in the consideration than the slight brightening of the information shown 32 ,

As highly reflective pigments 60 In this embodiment, for example, oxide multilayer interference pigments having a magnetic layer which ensure magnetic alignment can be used. The laser-modifiable background layer 30 In addition to infrared-absorbing inks, for example, metal layers, such as aluminum, copper or gold. Through the magnetic field 62 become the pigments 60 with advantage perpendicular to the direction of incidence of the laser radiation 64 aligned the marking laser. With laser application perpendicular to the color layer 34 , as in 3 shown, the pigments are then aligned parallel to the color layer plane. If the laser application takes place at a certain angle to the vertical, the pigments are also preferred 60 through the magnetic field 62 aligned at a certain angle to the color layer plane.

The information is transmitted by the laser radiation 64 in the affected areas 68 usually not completely destroyed in practice, as already taken into account in the above calculation of the contrast ratio. The laser-induced change may, instead of destruction, also be a bleaching or other modification of the applied areas. The laser-modifiable background layer 30 , the highly reflective pigments 60 and the laser parameters, in particular wavelength, power density, pulse duration and exposure time, are advantageously matched to one another such that a high modification of the background layer 30 with a low influence of the pigments 60 accompanied. Under certain circumstances, it may be a certain change in the pigments 60 be accepted by the laser exposure.

5 shows a further embodiment of the invention, in which by the magnetic field-induced transparency change a subject at the same time and register accurate both in the background layer 30 as well as in the color layer 34 can be introduced.

The starting point is a security element 80 the basically in 2 illustrated type, wherein the security element 80 a laser-modifiable background layer 30 contains, for example, a background layer with infrared-absorbing inks, with metal layers, such as aluminum, copper or gold, or with irreversible thermochromic dyes, combined with infrared absorbers. The microcapsules 36 the microcapsule-based paint layer 34 included in the embodiment of the 5 platelet-shaped, magnetically orientable pigments 82 , which are also formed laser-modified. For this purpose, for example, magnetic, multilayer interference pigments with metallic layers into consideration.

Now, an external magnetic field 84 put on the pigments 82 in a subarea 86 the color layer parallel to the plane of the color layer 34 aligns (left half in 5 (a) ) and in another subarea 88 perpendicular to the plane of the paint layer 34 aligns (right half in 5 (a) ). The subareas 86 . 88 forms a given motif, for example a pattern of alternating stripes 86 . 88 ,

In the aligned state of the pigments 82 now become the underground layer 30 and the color layer 34 at a normal angle of incidence with laser radiation 90 a marking laser acted upon. In the subarea 86 in which the pigments 82 parallel to the color layer plane and thus perpendicular to the direction of the laser radiation 90 are caused by the laser radiation 90 mainly only the pigments 82 modified as in the figure by the white filling of the modified pigments 92 indicated while hardly laser radiation 90 to the background layer 30 penetrates (left half in 5 (a) ). The modification of the pigments may be, for example, a laser-induced change in color, brightness or gloss.

In the subarea 88 in which the pigments 82 perpendicular to the color layer plane and thus parallel to the laser radiation 90 aligned, is the color layer 34 on the other hand transparent, so that there the laser radiation 90 the background layer 30 achieved and modified, as in the figure by the narrow hatching of the modified background layer 94 indicated (right half of the picture in 5 (a) ). The modification of the background layer can consist, for example, of a laser-induced change in color, brightness or gloss.

Be in the consideration of the security element 80 now the pigments 82 . 92 through an external magnetic field 84 aligned parallel to the color layer plane, as in 5 (b) shown, so block the pigments 82 . 92 the view of the underground layer 30 , The viewer therefore looks in the subarea 86 on the modified pigments 92 and in the subarea 88 on the unmodified pigments 82 so that through the subregions 86 . 88 formed stripe pattern due to the different appearance of the pigments 82 . 92 appears with a first visual impression.

Be considered when looking at pigments 82 . 92 by an external magnetic field 84 aligned perpendicular to the color layer plane, as in 5 (c) shown, so give the pigments 82 . 92 the view of the underground layer 30 free. The viewer therefore looks in the subarea 86 on the unmodified underground layer 30 and in the subarea 88 on the modified background layer 94 , so that depending on the design and modification of the background layer 30 that through the subregions 86 . 88 formed stripe pattern with a second visual impression appears.

By the simultaneous generation of the modification of the pigments 82 and the background layer 30 stand the modified areas of color layer 34 and underground layer 30 in the perfect register.

In the embodiment of the 6 a motif only becomes the microcapsule-based color layer 34 brought in. The starting point is a security element 100 the basically in 2 illustrated type, wherein the security element 100 any background layer 30 contains. On the underground layer 30 becomes a microcapsule-based color coat 34 whose microcapsules are platelet-shaped, magnetically alignable and laser-modifiable pigments 82 contain, for example, magnetic, multilayer interference pigments with metallic layers. The binder 102 the color layer 34 Contains particles in this embodiment 104 , which are barely visible to a viewer, but at the wavelength of the marking laser strongly scattering or absorbing effect. The particles 104 For example, for an Nd: YAG marking laser, they may be formed of titanium dioxide or iron oxide.

For introducing the motif into the color layer 34 becomes an external magnetic field 84 put on the pigments 82 the color layer parallel to the plane of the color layer 34 aligns. In the aligned state of the pigments 82 now becomes the color layer 34 in a subarea corresponding to the motif 106 with the laser radiation 108 of the Nd: YAG marker laser. The subarea 106 may, for example, the denomination "5" of the banknote 10 form. The laser parameters, in particular power density, pulse duration and exposure time, are chosen so that the pigments 82 be modified in the desired manner (reference numerals 92 ).

Due to the scattering or absorbing effect of the particles 104 becomes the energy of laser radiation 108 in the color layer 34 distributed so that the laser radiation 108 in the background layer 30 only arrives with an intensity that does not suffice for a visible change.

Be in the consideration of the security element 100 now the pigments 82 . 92 through an external magnetic field 84 aligned perpendicular to the color layer plane, as in 6 (b) represented, so give the pigments 82 . 92 the view of the underground layer 30 free. The viewer thus sees one in the background layer 30 possibly contained information, for example, in the supervision of the 6 (c) logo shown 32 ,

Be considered when looking at pigments 82 . 92 by an external magnetic field 84 aligned parallel to the color layer plane, as in 6 (d) represented, so block the pigments 82 . 92 the view of the underground layer 30 , The viewer therefore looks in the subarea 106 on the modified pigments 92 and outside the subarea 106 on the unmodified pigments 82 , Because of the different appearance of the pigments 82 . 92 now appears to the viewer through the sub-area 106 formed motif in the form of the denomination "5", as in the supervision of 6 (e) shown.

It should also be noted that in the context of the present invention the background layer can be applied to any substrates, in particular paper, plastic or a paper-plastic composite.

LIST OF REFERENCE NUMBERS

10

bill

12

Banknote paper

14

security element

16

Background layer

20

verification device

22

magnetic field lines

26, 28

areas

30

Background layer

32

information

34

microcapsule-based paint layer

36

microcapsules

38

capsule shell

40

carrier fluid

42

pigment

50, 52

appearances

54

Positions without microcapsules

56

Rest of the information

60

highly reflective pigments

62

external magnetic field

64

laser radiation

66

reflected laser radiation

68

destroyed areas

70, 72

appearances

80

security element

82

laser-modifiable pigments

84

external magnetic field

86, 88

subregions

90

laser radiation

92

modified pigments

94

modified background layer ^

100

security element

102

binder

104

scattering or absorbing particles

106

subregion

108

laser radiation

Claims (14)

Process for the preparation of an optically variable security element with a microcapsule-based ink layer, in which U) a substrate layer is applied to a substrate F) a microcapsule-based ink layer is applied to the background layer containing in a binder a plurality of microcapsules each having a capsule shell, a carrier liquid enclosed in the capsule shell and a magnetically alignable platelet-shaped pigment which is substantially freely rotatable within the microcapsule and reversibly alignable by an external magnetic field, M) an external magnetic field is applied to align the rotatable pigments at least in a portion of the color layer in the microcapsules, and L) in the partial area with the aligned pigments by laser irradiation with a marking laser at least a portion of the pigments and / or at least a portion of the background layer is modified. A method according to claim 1, characterized in that in step U) a laser-modifiable background layer is applied, preferably a background layer with infrared-absorbing inks and / or metal layers. A method according to claim 2, characterized in that in step L) at least a portion of the background layer is modified by laser exposure, in particular destroyed or bleached. Method according to at least one of claims 1 to 3, characterized in that in step F) a microcapsule-based ink layer is applied, whose platelet-shaped pigments are reflective for the wavelength of the marking laser and are preferably formed by oxide multilayer interference layer pigments. Method according to at least one of claims 1 to 3, characterized in that in step F) a microcapsule-based ink layer is applied, whose platelet-shaped pigments are laser-modifiable with the marking laser and are preferably formed by multilayer interference pigments with metallic layers. Method according to at least one of claims 1 to 5, characterized in that in step F) a microcapsule-based ink layer is applied, the binder contains particles which act at the wavelength of the marking laser scattering or absorbing and preferably formed by titanium dioxide or iron oxide particles are. Method according to at least one of claims 1 to 6, characterized in that in step M) the pigments are aligned at least in a partial region of the ink layer perpendicular to the loading direction of the marking laser in step L). Method according to at least one of claims 1 to 7, characterized in that in step M) the pigments are aligned at least in a partial region of the ink layer parallel to the loading direction of the marking laser in step L). Method according to at least one of Claims 1 to 8, characterized in that the laser application in step L) takes place in a subregion in the form of patterns, characters or an encoding. Method according to at least one of claims 1 to 9, characterized in that the background layer in step U) in the form of information, in particular a pattern, characters or a coding is applied. Method according to at least one of claims 1 to 10, characterized in that the laser application in step L) with an infrared laser in the wavelength range of 0.8 .mu.m to 3 .mu.m, in particular with a Nd: YAG laser and / or Nd: YVO ₄ laser takes place. Security arrangement for securing security papers, documents of value, data carriers and the like with a security element producible according to one of claims 1 to 11 and with a verification element with a magnetic area. Safety arrangement according to claim 12, characterized in that in the magnetic region magnetic material in the form of patterns, lines, characters or a coding is present and / or that the magnetic region is magnetized substantially perpendicular to the plane of the verification element. Data carrier with a producible according to one of claims 1 to 11 security element, or with a security arrangement according to one of claims 12 or 13, wherein in the latter case the security element and the verification element of the security arrangement are preferably arranged geometrically on the data carrier so that the security element can be brought over the verification element by bending or folding the data carrier.

Images