EP2897812B1 - Security element with display arrangement - Google Patents

Description

The invention relates to a security element for securing security papers, documents of value and other data carriers, having a representation arrangement for displaying one or more reference images whose motifs are each formed by visually recognizable, contrasting metallic and non-metallic subregions. The invention also relates to methods for producing such a security element, as well as equipped with a security element disk.

Data carriers, such as valuables or identity documents, but also other valuables, such as branded articles, are often provided with security elements for securing purposes, which permit verification of the authenticity of the data carrier and at the same time serve as protection against unauthorized reproduction. Data carriers in the context of the present invention are in particular banknotes, stocks, bonds, certificates, vouchers, checks, high-quality admission tickets, but also other forgery-prone papers, such as passports and other identification documents, credit cards, health cards, as well as product security elements such as labels, seals, packaging and the like. The term "data carrier" in the following includes all such objects, documents and product protection means.

Security elements with optically variable elements, which give the viewer a different image impression from different viewing angles, play a special role in securing, since these can not be reproduced even with high-quality color copying machines. For example, the security elements can contain a tilting or changing picture, a moving picture or a stereo picture as a display arrangement.

For some time, so-called Moire magnification arrangements are used as security features. The principle of operation of such Moire magnification arrangements is described in the article " The moire magnifier ", MC Hutley, R. Hunt, RF Stevens and P. Savander, Pure Appl. Opt. 3 (1994), pp. 133-142 , described. In short, moiré magnification thereafter refers to a phenomenon that occurs when viewing a raster of identical image objects through a lenticular of approximately the same pitch. As with any pair of similar rasters, this results in a moire pattern consisting of a periodic arrangement of enlarged and possibly rotated images of the elements of the image raster. Contain the representations of the security elements differently colored motifs, they can be printed usually in a desired shape. The production is more difficult in motifs which are to be formed by contrasting metallic and non-metallic subregions, since metallizations can generally not be generated directly in motif form, but only over the entire surface, for example by vapor deposition of a metal layer in a vacuum vapor deposition process.

The document WO2006 / 125224 A2
discloses a security element according to
the preamble of claim 1.

Based on this, the present invention seeks to provide a security element of the type mentioned, which can be reliably manufactured with predetermined metallic and non-metallic portions. Also, advantageous methods for producing security elements of the type mentioned are to be specified.

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

According to the invention, the display arrangement of a security element mentioned above comprises a motif layer having a plurality of metallized pixels and non-metallized pixels and a viewing grid spaced from the motif layer of a plurality of viewing elements, the metallized pixels and the non-metallized pixels viewed in association with the Viewing grid to produce the visually recognizable, contrasting metallic and non-metallic portions of the target images. Furthermore, the motif layer according to the invention comprises an embossed structure with elevations and depressions, wherein the non-metallized image elements of the motif layer are formed by non-metallized elevations of the embossed structure and the metallic image elements are formed by substantially metallized depressions of the embossed structure. At least a portion of the substantially metallized depressions contain, in an area fraction between 0.1% and 25%, small, raised support structures which are not visually discernible when viewed with the viewing grid.

Since the support structures arranged in the depressions are themselves generally not metallized, as explained in more detail below, the depressions with the support structures are referred to as "substantially" metallized in the context of this description. The metallic impression of the metallic picture elements formed by the depressions is not impaired by the support structures for the viewer, since these are not visually recognizable when viewed with the viewing grid.

In an advantageous embodiment, at least some of the substantially metallized depressions contain the support structures in an area ratio of between 2.5% and 10%.

Furthermore, it is conceivable in principle, although not presently preferred, for at least some of the essentially metallized depressions to contain the support structures in an area fraction of more than 25%. In particular, at least under suitable lighting conditions, even with a comparatively high surface portion of the support structures of, for example, 50%, the deterioration of the metallic impression by the support structures can be regarded as negligible by the viewer, so that the target images remain visually recognizable, albeit with reduced contrast.

In an advantageous embodiment, the support structures in the depressions are irregular, for example, stochastically distributed. Alternatively, the support structures in the depressions may also be arranged regularly in a grid whose moiré effects with the viewing grid remain below the resolution limit of the human eye or, as explained in more detail below, are completely avoided by suitable arrangement of the support structures with respect to the viewing elements ,

The height of the support structures preferably corresponds to the depth of the recesses in which they are arranged. In general, however, the height of the support structures may also be lower, as long as they ensure a sufficient distance of an adhesive-coated acceptor film from the bottom of the recesses in the production, as described in more detail below.

In advantageous embodiments, the support structures comprise pillars of circular, oval, triangular, rectangular or polygonal cross-section, the cross-section of the pillars preferably having an area between 0.25 μm ² and 25 μm ² .

In other, likewise advantageous embodiments, the support structures comprise irregular, continuous web structures in which the width of the web structures is preferably between 0.1 μm and 5 μm.

According to further, likewise advantageous embodiments, the support structures comprise non-contiguous web elements which each consist of one or more line pieces and whose width is preferably between 0.1 μm and 5 μm.

Also advantageously, the support structures may comprise straight, parallel web elements whose width is preferably between 0.1 μm and 5 μm.

The mentioned types of support structures can be combined with each other so that different recesses contain different support structure types. Also in the same recess several different types of support structures can be provided.

Furthermore, it can be provided with advantage that the support structures in a subarea contain hidden information in the form of characters or a coding so as to integrate an additional authenticity feature in the security element.

Preferably, all depressions whose dimensions exceed a maximum dimension, provided with support structures of the type mentioned. The advantageous for a presentation arrangement according to the invention maximum dimensions are of various parameters, in particular the depth of the wells, the pressure used in the laminating process, the Thickness of the adhesive layer, etc. dependent. Advantageous maximum dimensions can be determined by a person skilled in the art for each parameter selection with the aid of less orienting tests. By way of example, all depressions which have a dimension of more than 30 μm (maximum dimension) in at least one spatial direction are provided with support structures.

The viewing elements of the viewing grid are advantageously formed by spherical lenses, aspherical lenses, cylindrical lenses or one or two-dimensionally focusing micro-cavity mirrors. In further preferred variants of the invention, the viewing elements are formed by pinhole apertures, slotted apertures, mirrored apertured or slit apertures, Fresnel lenses, GRIN lenses (Gradient Refraction Index), zone plates, holographic lenses, Fresnel mirrors, zone mirrors or other elements with focussing or also fading out effects.

The motif layer of the representation arrangement preferably lies in the focal plane of the lenses or concave mirrors.

In a preferred embodiment, the viewing elements are formed by cylindrical lenses and the support structures are formed by parallel, straight web elements, which are at an angle between 60 ° and 120 °, preferably between 85 ° and 95 °, particularly preferably of 90 ° to the axis of the cylindrical lenses extend. In this way, even with a regular arrangement of the support structures in a grid, moire effects with the viewing grid can be avoided.

The representation arrangement itself may in particular be a change picture, a motion picture, a morph picture or a stereo picture, but with advantage also a micro-optical display arrangement, in particular a moiré magnification arrangement, a moire-type magnification device or a modulo magnification device. The basic principle of such micro-optical representation arrangements is in the document WO 2009/000528 A1 explained, the disclosure of which is included in the present description in this regard.

As stated above, the motif layer of the presentation arrangement is preferably located in the focal plane of the lenses or concave mirrors. The motif layer may, however, in particular in the case of non-magnifying representational arrangements, for example in the case of non-enlarging change images, also lie in a plane (parallel) which deviates slightly from the focal plane of the lenses or concave mirrors. In this case, although the angular ranges in which the motifs are recognizable at the same time (or in which one motif "transitions" into another), at the expense of the angular ranges in which only one of the motifs can be seen, the contrast or contrast increases However, this does not affect the sharpness of the subjects.

In advantageous embodiments, an additional structuring, preferably a diffractive structure, a structure having a matting or scattering effect and / or a nanostructuring, is introduced into the depressions of the embossed structure.

Likewise advantageously, the motif layer can be provided over the entire area or over a partial area, for example in the form of a halftone display, with at least one printing ink and / or with at least one reflective coating material, preferably a metal, a color-shifting system, a high refractive index material, metal pigments or effect pigments.

The invention also includes a data carrier equipped with a security element of the type described above. The security element may in particular be embedded in the data carrier or applied to the data carrier.

• (a) Herstellen einer Donorfolie durch
  1. (i) Ausbilden einer Prägestruktur mit Erhebungen und Vertiefungen und mit in den Vertiefungen in einem Flächenanteil zwischen 0,1% und 25% angeordneten erhabenen Stützstrukturen, mindestens in einem Teilbereich einer Hauptfläche eines ersten Folienmaterials oder in einer prägbaren Schicht auf mindestens einem Teilbereich einer Hauptfläche eines ersten Folienmaterials,
     wobei die Erhebungen und die Vertiefungen Bildelemente einer Motivschicht der Darstellungsanordnung erzeugen, die bei Betrachtung der Motivschicht mit einem Betrachtungsraster der Darstellungsanordnung visuell erkennbare, kontrastierende metallische und nicht-metallische Teilbereiche der Sollbilder erzeugen,
  2. (ii) Auftragen einer Metallbeschichtung mindestens auf einen Teilbereich der Prägestruktur,
• (b) Herstellen einer Akzeptorfolie durch Auftragen einer Klebstoffschicht mindestens auf einen Teilbereich einer Hauptfläche eines zweiten Folienmaterials,
• (c) Kaschieren der Donorfolie und der Akzeptorfolie mittels der Klebstoffschicht derart, dass mindestens ein Teilbereich der beschichteten Prägestruktur und ein Teilbereich der Klebstoffschicht miteinander in Kontakt kommen, wobei in dem Kontaktbereich die Metallbeschichtung auf den Erhebungen der Prägestruktur mit der Klebstoffschicht der Akzeptorfolie verklebt,
• (d1) Transferieren der im Kontaktbereich auf den Erhebungen der Donorfolie vorliegenden Metallbeschichtung auf die Klebstoffschicht der Akzeptorfolie durch Trennen von Donorfolie und Akzeptorfolie, wodurch aus der Donorfolie eine Motivschicht mit einer Mehrzahl von metallisierten Bildelementen und nicht-metallisierten Bildelementen entsteht, und
• (e1) Herstellen einer Darstellungsanordnung durch Kombinieren der Motivschicht der Donorfolie mit einem Betrachtungsraster aus einer Mehrzahl von Betrachtungselementen, derart, dass die metallisierten Bildelemente und die nicht-metallisierten Bildelemente bei Betrachtung mit dem Betrachtungsraster die visuell erkennbaren, kontrastierenden metallischen und nicht-metallischen Teilbereiche der Sollbilder erzeugen.

The invention also includes a method for producing a security element having a representation arrangement for displaying one or more target images whose motifs are each formed by visually recognizable, contrasting metallic and non-metallic subregions, with the following method steps:

• (a) preparing a donor sheet
  1. (i) forming an embossed structure with elevations and depressions and with raised support structures arranged in the depressions in an area fraction between 0.1% and 25%, at least in a partial area of a main area of a first foil material or in an embossable layer on at least a partial area of a main area a first sheet material,
     wherein the elevations and the recesses generate picture elements of a motif layer of the representation arrangement, which generate visually recognizable, contrasting metallic and non-metallic parts of the set images when the motif layer is viewed with a viewing grid of the presentation arrangement,
  2. (ii) applying a metal coating to at least a portion of the embossed structure,
• (b) producing an acceptor film by applying an adhesive layer to at least a portion of a major surface of a second film material,
• (c) laminating the donor film and the acceptor film by means of the adhesive layer such that at least a portion of the coated embossed structure and a partial region of the adhesive layer come into contact with one another, wherein in the contact region the metal coating adheres to the elevations of the embossed structure with the adhesive layer of the acceptor film,
• (d1) transferring the metal coating present in the contact region on the elevations of the donor film to the adhesive layer of the acceptor film by separating donor film and acceptor film, whereby a motif layer having a plurality of metallized picture elements and non-metallized picture elements is formed from the donor film, and
• (e1) producing a presentation arrangement by combining the motif layer of the donor sheet with a viewing grid of a plurality of viewing elements such that the metallized picture elements and the non-metallized picture elements, when viewed with the viewing grid, form the visually recognizable, contrasting metallic and non-metallic portions of the Generate target images.

In a preferred embodiment, the viewing elements are impressed before or after step (a) (i) into the further main surface of the first film material opposite the main surface of the first film material or into an embossable layer on the further main surface of the first film material opposite the main surface.

In other, likewise advantageous embodiments, an additional structuring, preferably a diffractive structure, a structure having a matting or scattering effect and / or a nanostructuring, is introduced into the recesses of the embossed structure in step (a).

• (a) Herstellen einer Donorfolie durch
  1. (i) Ausbilden einer Prägestruktur mit Erhebungen und Vertiefungen und mit in den Vertiefungen in einem Flächenanteil zwischen 0,1% und 25% angeordneten erhabenen Stützstrukturen, mindestens in einem Teilbereich einer Hauptfläche eines ersten Folienmaterials oder in einer prägbaren Schicht auf mindestens einem Teilbereich einer Hauptfläche eines ersten Folienmaterials,
     wobei die Erhebungen und die Vertiefungen Bildelemente einer Motivschicht der Darstellungsanordnung erzeugen, die bei Betrachtung der Motivschicht mit einem Betrachtungsraster der Darstellungsanordnung visuell erkennbare, kontrastierende metallische und nicht-metallische Teilbereiche der Sollbilder erzeugen,
  2. (ii) Auftragen einer Metallbeschichtung mindestens auf einen Teilbereich der Prägestruktur,
• (b) Herstellen einer Akzeptorfolie durch Auftragen einer Klebstoffschicht mindestens auf einen Teilbereich einer Hauptfläche eines zweiten Folienmaterials,
• (c) Kaschieren der Donorfolie und der Akzeptorfolie mittels der Klebstoffschicht derart, dass mindestens ein Teilbereich der beschichteten Prägestruktur und ein Teilbereich der Klebstoffschicht miteinander in Kontakt kommen, wobei in dem Kontaktbereich die Metallbeschichtung auf den Erhebungen der Prägestruktur mit der Klebstoffschicht der Akzeptorfolie verklebt,
• (d2) Transferieren der im Kontaktbereich auf den Erhebungen der Donorfolie vorliegenden Metallbeschichtung auf die Klebstoffschicht der Akzeptorfolie durch Trennen von Donorfolie und Akzeptorfolie, wodurch aus der Akzeptorfolie eine Motivschicht mit einer Mehrzahl von metallisierten Bildelementen und nicht-metallisierten Bildelementen entsteht, und
• (e2) Herstellen einer Darstellungsanordnung durch Kombinieren der Motivschicht der Akzeptorfolie mit einem Betrachtungsraster aus einer Mehrzahl von Betrachtungselementen, derart, dass die metallisierten Bildelemente und die nicht-metallisierten Bildelemente bei Betrachtung mit dem Betrachtungsraster die visuell erkennbaren, kontrastierenden metallischen und nicht-metallischen Teilbereiche der Sollbilder erzeugen.

In addition, the invention also includes a method for producing a security element with a representation arrangement for representing a or multiple target images whose motifs are each formed by visually recognizable, contrasting metallic and non-metallic subregions, with the following process steps:

• (a) preparing a donor sheet
  1. (i) forming an embossed structure with elevations and depressions and with raised support structures arranged in the depressions in an area fraction between 0.1% and 25%, at least in a partial area of a main area of a first foil material or in an embossable layer on at least a partial area of a main area a first sheet material,
     wherein the elevations and the recesses generate picture elements of a motif layer of the representation arrangement, which generate visually recognizable, contrasting metallic and non-metallic parts of the set images when the motif layer is viewed with a viewing grid of the presentation arrangement,
  2. (ii) applying a metal coating to at least a portion of the embossed structure,
• (b) producing an acceptor film by applying an adhesive layer to at least a portion of a major surface of a second film material,
• (c) laminating the donor film and the acceptor film by means of the adhesive layer in such a way that at least a partial region of the coated embossed structure and a partial region of the adhesive layer come into contact with one another, wherein in the contact region the metal coating adheres to the elevations of the embossed structure with the adhesive layer of the acceptor film,
• (d2) transferring the metal coating present in the contact region on the elevations of the donor film onto the adhesive layer of the acceptor film by separating the donor film and the acceptor film, resulting in the Acceptor foil a motif layer with a plurality of metallized pixels and non-metallized pixels is formed, and
• (e2) producing a presentation arrangement by combining the motif layer of the acceptor sheet with a viewing grid of a plurality of viewing elements, such that the metallized pixels and the non-metallized picture elements, when viewed with the viewing grid, form the visually recognizable, contrasting metallic and non-metallic portions of the Generate target images.

In advantageous embodiments, in step (d1) or in step (d2) of the above method, the metal coating present in the contact region on the raised support structures of the donor film can also be transferred to the adhesive layer of the acceptor film by separating donor film and acceptor film.

On the embossed structure, the metal coating is applied over the entire surface or part of the area. It should be noted that the metal coating must later be partially replaced again. It must therefore not adhere too strongly to the substrate, at least less strongly than the achievable bond strength with the later to be used adhesive. A sufficiently low adhesive force may possibly already be achieved by a suitable choice of the materials for the film material or the embossable layer. Preferably, however, prior to the application of the metal coating in step (a) (ii), an adhesion-reducing treatment of the surface of the embossed structure to be coated is undertaken.

In the above methods, the motif layer after step (d1) or step (d2) is advantageously over the entire area or part of the area, for example in the form of a half-tone display, with at least one printing ink and / or provided with at least one reflective coating material, preferably a metal, a color-shifting system, a high refractive index material, metal pigments or effect pigments. With particular advantage, one or more printing inks are first applied and then additionally a reflective coating material, in particular a full-surface metallization.

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.

Fig. 1

eine schematische Darstellung einer Banknote mit einem erfindungsgemäßen Sicherheitselement, das ein Wechselbild mit zwei unterschiedlichen Sollbildern enthält,

Fig. 2

schematisch den Aufbau eines erfindungsgemäßen Sicherheitselements, beispielsweise des Transferelements der Fig. 1 im Querschnitt,

Fig. 3

schematisch die Motivschicht eines erfindungsgemäßen Sicherheitselements,

Fig. 4

in (a) und (b) schematisch die Donorfolie und die Akzeptorfolie bei Zwischenschritten der Herstellung eines erfindungsgemäßen Sicherheitselements,

Fig. 5

die Akzeptorfolie der Fig. 4(b) nach der Trennung der beiden Folien,

Fig. 6

in (a) und (b) schematisch die Donorfolie in zwei Zwischenschritten bei der Herstellung einer herkömmlichen Motivschicht,

Fig. 7

in (a) und (b) schematisch die Donorfolie in zwei Zwischenschritten bei der Herstellung einer Motivschicht eines erfindungsgemäßen Sicherheitselements,

Fig. 8,9

einige vorteilhafte Gestaltungen erfindungsgemäßer Stützstrukturen, und

Fig. 10

ein Ausführungsbeispiel eines Sicherheitselements mit einer Darstellungsanordnung in Gestalt einer Modulo-Vergrößerungsanordnung.

Show it:

Fig. 1

a schematic representation of a banknote with a security element according to the invention, which contains a change picture with two different target images,

Fig. 2

schematically the structure of a security element according to the invention, for example, the transfer element of Fig. 1 in cross section,

Fig. 3

schematically the motif layer of a security element according to the invention,

Fig. 4

in (a) and (b) schematically the donor sheet and the acceptor sheet in intermediate steps of the production of a security element according to the invention,

Fig. 5

the acceptor foil of Fig. 4 (b) after the separation of the two films,

Fig. 6

in (a) and (b) schematically shows the donor film in two intermediate steps in the production of a conventional motif layer,

Fig. 7

in (a) and (b) schematically the donor film in two intermediate steps in the production of a motif layer of a security element according to the invention,

Fig. 8.9

some advantageous designs of inventive support structures, and

Fig. 10

an embodiment of a security element with a representation arrangement in the form of a modulo magnification arrangement.

The invention will now be explained using the example of security elements for banknotes and other value documents. FIG. 1 shows a schematic representation of a banknote 10, which is provided with a security element according to the invention in the form of a glued transfer element 12. In the exemplary embodiment, the transfer element 12 represents a change image which presents to the viewer different target images 14A and 14B from two different viewing directions. The target images 14A, 14B each show a motif formed by visually recognizable and contrasting metallic and non-metallic portions 16A, 16B and 18A, 18B, respectively.

In the exemplary embodiment, the motifs are formed by metallic glossy letters "A" and "B" in front of a monochrome, non-metallic background, the viewer viewed obliquely from the left the letter "A", viewed obliquely from the right the letter "B "perceives. By tilting the banknote, the appearance of the security element alternates between the two target images 14A, 14B. It is understood that in practice mostly complex motifs, for example the denomination of the banknote, geometric patterns, portraits, architectural, technical or nature motives are used. The motifs can also be present in particular in the form of screened half-tone representations. Also, a change picture may contain more than two reference pictures or the security element may have a motion picture, a pump picture, a morph picture or a stereo picture instead of a change picture. In addition, the security element can also be designed such that the appearance does not change back and forth as described above in an "east-west tilting" of the security element between two or more target images, but in a tilting about any other axis, for example a "north-south tipping". In a north-south tilting the viewer perceives when viewed obliquely from above, for example, the letter "A" and viewed obliquely from below the letter "B" true.

However, the invention is not limited in any way to alternating images or the variants mentioned. Rather, the invention can be found in all representational arrangements with a partly metallic and partly non-metallic motif layer application. The invention is also not limited to the banknote transfer elements used for illustration, but can also be used, for example, in security threads, wide security strips, or cover sheets that overlie a window area or a through opening of a document are arranged.

FIG. 2 schematically shows the structure of a security element 20 according to the invention, for example, the transfer element 12 of Fig. 1 in cross section. Shown here are, as in the other figures, only necessary for the explanation of the principle of operation parts of the structure.

The security element 20 of Fig. 2 has a carrier 22 in the form of a transparent plastic film, for example, about 20 microns thick PET film. The upper side of the carrier 22 is provided with a viewing grid in the form of a plurality of parallel cylindrical lenses 24 whose width b in the exemplary embodiment is b = 20 μm. On the underside of the carrier 22, a motif layer 26 is formed, which is divided into parallel to the cylindrical lenses 24 extending narrow strips 28A, 28B with a width of 10 microns each. The carrier foil 22 and the cylindrical lenses 24 are matched to one another such that the motif layer 26 is located in the focal plane of the cylindrical lenses 24.

When viewing the security element 20 from the viewing direction 30A, only the stripes 28A are visible due to the focusing effect of the cylindrical lenses 24, and only the stripes 28B are visible when viewed from the viewing direction 30B. Therefore, the strips 28A and 28B settle for the viewer to the desired target images, such as the target images 14A, 14B of Fig. 1 together. In the design of the motif layer 26, the desired desired images 14A, 14B were subdivided in a manner known per se into parallel strips 28A, 28B of the desired width and the strips thus obtained were assembled alternately with the motif layer 26. The parallel strips 28A, 28B need not be the same width. For example For example, the strip 28A may also have a width of 5 μm and the strip 28B may have a width of 15 μm. The proportion of the respective strip in the overall width has an effect on the angle range in which the desired target images 14A, 14B are visible to the viewer.

As in Fig. 2 As shown, the security element 20 typically includes further layers 32, such as protective, masking or other functional layers, which are not essential to the present invention and therefore will not be described further.

Tilting or alternating pictures showing different colored subjects are known. In order to produce the differently colored motifs, the motif parts of the target images lying in the individual strips 28A, 28B are usually printed in the desired form. The peculiarity of the alternating images described here consists in the fact that the motifs of the target images 14A, 14B are formed by contrasting metallic and non-metallic subregions. As a rule, however, metallizations can not be generated directly in a motif, but only over the entire surface, for example by vapor deposition of a metal layer in a vacuum vapor deposition process.

• Mit Bezug auf die schematische Darstellung der Fig. 3 umfasst die Motivschicht 26 eine auf den Träger 22 aufgebrachte Prägeschicht 40 mit einer Prägestruktur mit Erhebungen 42 und Vertiefungen 44. Die Erhebungen 42 der Prägestruktur sind dabei nicht-metallisiert und stellen nicht-metallisierte Bildelemente dar, die bei der Betrachtung die nicht-metallischen Teilbereiche 18A, 18B der Sollbilder erzeugen. Die Vertiefungen 44 der Prägestruktur sind dagegen im Wesentlichen mit einer Metallisierung 46 versehen und stellen metallisierte Bildelemente dar, die bei der Betrachtung die metallischen Teilbereiche 16A, 16B der Sollbilder bilden.

In order nevertheless to be able to produce the required structuring into metallic and non-metallic subregions, the procedure is as follows:

• With reference to the schematic representation of Fig. 3 For example, the motif layer 26 comprises a stamping layer 40 applied to the carrier 22 and having an embossed structure with elevations 42 and depressions 44. The elevations 42 of the embossed pattern are non-metallized and represent non-metallized picture elements which, when viewed, the non-metallic subregions 18A , 18B generate the target images. The depressions 44 of the embossed structure are On the other hand, they are essentially provided with a metallization 46 and represent metallized picture elements which, when viewed, form the metallic subregions 16A, 16B of the target images.

The procedure in the production of such a security element is in Fig. 4 illustrated. With reference first to Fig. 4 (a) In this case, a donor film 50 in the form of a transparent plastic film 22 is assumed, which is coated with a transparent embossable layer 40. In the embossable layer 40, an embossed structure is impressed, the sequence of elevations 42 and depressions 44 is determined by the motifs of the desired target images, for example, the wells 44 represent the foreground and the surveys 42 represent the background of the respective subjects or vice versa. The structure depth of the embossed structure is preferably in the range between 0.2 μm and 10 μm and the line width is preferably in the range between 0.2 μm and the width of the strips 28A, 28B, typically 5 μm to 20 μm.

On the embossed structure, a metal is then vapor-deposited over the entire area, so that a full-surface metal coating 48 is formed. For vapor deposition, the common materials, such as aluminum, silver, gold, copper, zinc, chromium and alloys thereof come into question. As in Fig. 4 (a) shown, both the elevations 42 and the recesses 44 are covered with the metal coating 48 initially. Before the vapor deposition of the metal coating 48, an adhesion-reducing treatment of the surface to be coated is preferably carried out. The thickness of the metal coating 48 depends on the desired subsequent reflection behavior and on the metal used and is for example advantageously about 30 to 50 nm for aluminum.

The donor sheet 50 thus produced is now filled with an in Fig. 4 (b) shown acceptor 52 brought into contact. The acceptor film 52 consists of a transparent film 54, which is coated over its entire surface with a transparent adhesive layer 56 on one of its main surfaces. The donor film 50 and the acceptor film 52 are pressed together, preferably under elevated pressure and elevated temperature, in order to transfer the metallization of the elevations 42 from the donor film 50 to the acceptor film 52. After separating the two sheets, preferably by means of a separation winding, the projections 42 of the donor sheet 50 are demetallized, while the metal coating 48 in the recesses 44 has not been transferred and therefore remains on the donor sheet 50, as in FIG Fig. 3 shown.

As in Fig. 5 As shown, the acceptor sheet 52 after separation contains the transferred metal coating portions 58 of the bumps 42 and thus has a metallization pattern inverted compared to the donor sheet. While the generation of a change image using the donor sheet 50 is described in detail herein, an alternate image may also be made using the acceptor sheet 52.

A difficulty of the metal transfer method described may result from the sequence of elevations 42 and depressions 44 of the embossed structure being predetermined by the motifs of the target images, so that usually there is no regular alternating sequence of elevations and depressions, as in the schematic representation of FIG FIGS. 3 and 4 shown. Rather, with arbitrary choice of subject, large contiguous elevation or depression areas can result, which should be demetallised in the finished security element (elevation areas) or metallized (depression areas). While large survey areas are demetallized easily with the described metal transfer process can remain troublesome in many areas of deep metalization.

To illustrate the possible problems shows Fig. 6 a region 60 of the motif layer 26, in which both target images 14A, 14B of the alternating image have metallized subregions. In the embodiment of Fig. 1 For example, these are those surface areas of the transfer element 12 in which the metallic parts of the letters "A" and "B" overlap. Since metallized picture elements are formed in the described metal transfer method by depressions of the embossed structure, the embossed pattern in this area contains recesses in both the strips 28A of the first target image and in the strips 28B of the second reference image. As a result, a large contiguous recessed area 62 can arise which, depending on the specific shape of the motifs, can have an extent of more than 100 μm or even several millimeters.

FIG. 6 (a) first shows an intermediate step in the production of the security element, namely the donor sheet 50 after full-surface coating of the embossed structure with metal 48, according to the situation of Fig. 4 (a) , In the subsequent laminating process with the acceptor foil 52 of FIG Fig. 4 (b) For example, the adhesive layer 56 of the acceptor film in the large recessed areas 62 can be pushed to the bottom of the recess, so that the acceptor film 52 is also adhesively bonded there to the metal coating 48. During the subsequent separation winding, metal is then undesirably removed from the depression area 62 as a result of the bonding, so that the in Fig. 6 (b) shown metallization error 64 arise.

In order to avoid such metallization errors 64, are in the in Fig. 7 shown additional embossing structures 70 in those recessed areas 72 of the embossing layer 40, which occupy more than two strip widths 28A, 28B. The support structures 70 are small raised structures, in particular webs or pillars, which, as in Fig. 7 (a) shown in the larger recessed areas 72, the Abtauchen the acceptor 52 to the bottom of the recess and thus prevent the unwanted transfer of metal 48 from the recesses 72 out.

Since the metal deposited on the support structures 70 is usually also removed during parting, the support structures 70 must be designed in such a way that they can not be visually recognized when there is a lack of metallization when viewing the motif layer with the viewing grid. The support structures 70 are thus fundamentally different from the non-metallized protrusions 42, which are just the non-metallized picture elements which, when viewed with the viewing grid, produce the visually recognizable non-metallic portions of the target images.

In the embodiment shown, the visual unrecognizability of the support structures 70 is ensured by the fact that the support structures 70 occupy only 2.5% of the area of the recess 72 in which they are arranged, and that the support structures 70 also not in the grid of Microlenses 24 and the strip 28A, 28B are arranged. This can be achieved, for example, by an irregular arrangement of the support structures 70, or else by a regular arrangement in a grid whose moire effects with the lenticular grid 24 remain below the resolution limit of the human eye. In representational arrangements with cylindrical lenses In particular, support structures are also advantageous, the largest dimension of which extends largely perpendicular to the axis of the cylindrical lenses.

Some advantageous designs of inventive support structures are in the FIGS. 8 and 9 illustrated. The figures show in plan view of the motif layer only a few of the support structures, as they can be arranged over the surface of a large-scale depression.

In the Fig. 8 Support structures shown can be used both in display arrangements with cylindrical lenses as well as in display arrangements with non-cylindrical lenses, such as the above-mentioned modulo magnification arrangements. The pillars 80 are small cylindrical elevations with a cross-sectional diameter of 0.7 microns to 2 microns. The cross section of the buttresses 80 may also be non-circular, for example oval, triangular, rectangular or generally polygonal. The simultaneous use of buttresses 80 with different cross-sections also suppresses possible moire effects. In Fig. 8 For example, when the pillars 80 are irregularly arranged, a regular array is contemplated that does not produce any visible moiré effects with the viewing grid.

In the Fig. 8 Also shown support webs 82 are narrow, non-contiguous webs with a width of 0.1 microns to 5 microns and a length of several microns. They can also be considered as supporting pillars with rectangular cross section.

The support structures may be further formed by irregularly extending, interconnected web structures 84 as shown at the bottom left in FIG Fig. 8 shown. Another variant is the bottom right in Fig. 8 shown web elements 86, which are each composed of one or more line pieces. With such web elements 86, hidden information 88, such as the "G + D" logo, can additionally be integrated into the motif layer of the security element. The hidden information 88 is visually unrecognizable due to its small dimensions when viewing the motif layer without tools. With a strong magnifying glass or a microscope, the hidden information can be made visible and used to authenticate the security element.

In the Fig. 9 shown support structure designs are particularly well suited for use with cylindrical lenses whose axis is parallel to the direction 90. The parallel webs 92 have a width of 0.1 to 5 .mu.m to each other at a distance of 10 to 30 microns. The webs 92 extend perpendicular to the axis 90 of the cylindrical lenses and thus in a division of the motif layer in parallel strips 28A, 28B ( Fig. 2 ) also perpendicular to the strip extension.

Optionally, concealed information 94 may be included in the parallel lands, such as the logo "G + D" shown, which, due to its small size, is not visually recognizable without aids, but can be visualized with a strong magnifying glass or microscope for authentication ,

In an alternative design, short supporting webs 96 are provided as support structures, all of which run perpendicular to the axis 90 of the cylindrical lenses, and whose position varies irregularly, as in the lower half of FIG Fig. 9 shown.

The height of the support structures preferably corresponds to the depth of the recesses, but it may also be chosen smaller or larger. It is only essential that they prevent the adhesive layer of the acceptor film from being pressed through to the bottom of the recesses in the laminating process.

The foregoing is not intended to be construed as limiting the invention in any way to alternate images. Rather, the invention is generally applicable to display arrangements with a viewing element grid, in particular a lenticular grid.

So shows Fig. 10 an embodiment of a security element 100 with a representation arrangement in the form of a modulo magnification arrangement. In this case, a UV embossing lacquer is applied to a carrier 102, which is formed by a transparent PET film 19 μm thick, into which a parallelogram grid of spherical microlenses 104 having a diameter of approximately 20 μm is embossed. On the underside of the carrier 102, a motif layer 106 having an embossed structure 108 is arranged, whose non-metallized elevations 118 and metallized depressions 120 represent the imaged areas of a predetermined reference image. How the imaged areas of a modulo magnification arrangement can be determined from a predetermined target image is described in the publication WO 2009/000528 A1 described in detail. The relevant disclosure of the WO 2009/000528 A1 is included in the present description.

Depending on the motif of the predetermined target image, the depressions 120 of adjacent imaged regions can be supplemented to form an extended depression region 110. To avoid metallization errors, In the exemplary embodiment shown, those depression regions 110 whose dimension exceeds 30 μm in one spatial direction are provided with support structures 92 in the form of cylindrical pillars (FIG. Fig. 8 ) Mistake. The support structures 92 have in the embodiment of Fig. 10 Each has a diameter of 1.5 microns and are distributed in an area ratio of about 3% irregularly in the recessed areas 110. During the laminating process, the support structures 92 reliably prevent the adhesive layer 56 of the acceptor foil 52 from escaping to the bottom of the depression regions 110. The motif layer 106 formed after lamination and release winding was provided with a full-surface ink layer 112 and a full-surface metallization 114. Reference numeral 116 denotes further layers of the structure of the security element, for example primer, opaque white or heat-sealable layers.

Due to their small size and their irregular arrangement, the support structures 92 and / or the lack of metallization at the location of the support structures in the recessed areas 110 are not visually discernible when viewed with the grid of spherical microlenses.

In further embodiments not shown here, the embossing structure of the donor film 20 in the depressions may additionally be provided with a further, finer structuring. Such a structuring is formed, for example, by diffractive microrelief structures carrying holographic information or hologram gratings for producing black structures. Of course, other structures, such as structures with matting or scattering effect or reflective microrelief structures are possible. Also possible are sub-wavelength gratings or nanostructures, in particular moth-eye structures. In this form of structuring, additional colourfulness (subwavelength lattice) or a blackening (moth-eye structures) are generated. In particular, different additional structuring may be provided in each of the recesses of the regions of the embossed structure assigned to different desired images or in the depressions of different subregions of the embossed structure assigned to a desired image.

LIST OF REFERENCE NUMBERS

10

bill

12

transfer element

14A, 14B

target images

16A, 16B

metallic parts

18A, 18B

non-metallic parts

20

security element

22

carrier

24

cylindrical lenses

26

motif layer

28A, 28B

strip

30A, 30B

viewing directions

32

more layers

40

embossing layer

42

surveys

44

wells

46

metallization

48

full-surface metal coating

50

donor sheet

52

Akzeptorfolie

54

transparent film

56

adhesive layer

58

transferred metal coating parts

60

Area of the motif layer

62

large areas of specialization

64

Metallisierungsfehler

70

support structures

72

focus areas

80

buttress

82

supporting webs

84

web structures

86

web elements

88

hidden information

90

Direction of the cylindrical lens axes

92

parallel bars

94

hidden information

96

short support bars

100

security element

102

carrier

104

spherical microlenses

106

motif layer

108

embossed structure

110

extended well area

112

coat of paint

114

metallization

116

more layers

118

surveys

120

wells

Claims (19)

1. A security element (100) for safeguarding security papers, value documents and other data carriers, having a display arrangement for displaying one or more target images (14A, 14B) whose motifs are formed in each case by visually perceptible, contrasting metallic (16A, 16AB) and non-metallic (18A, 18B) sub-regions,
   the display arrangement including a motif layer (106) having a plurality of metalized image elements and non-metalized image elements and, spaced apart from the motif layer, a viewing grid composed of a plurality of viewing elements (104), and the metalized image elements and the non-metalized image elements producing the visually perceptible, contrasting metallic and non-metallic sub-regions of the target images (14A, 14B) when viewed with the viewing grid, the motif layer (106) comprising an embossing pattern having elevations (118) and depressions (110,120), the non-metalized image elements of the motif layer being formed by non-metalized elevations (118) in the embossing pattern, and the metallic image elements by substantially metalized depressions (110,120) in the embossing pattern, characterized in that
   at least a portion of the substantially metalized depressions (110) includes, in an area fraction of between 0.1% and 25%, small, elevated support structures (92) that are not visually perceptible when viewed with the viewing grid.
2. The security element according to claim 1, characterized in that at least a portion of the substantially metalized depressions includes the support structures in an area fraction of between 2.5% and 10%.
3. The security element according to claim 1 or 2, characterized in that the support structures are distributed irregularly in the depressions.
4. The security element according to at least one of claims 1 to 3, characterized in that the height of the support structures corresponds to the depth of the depressions in which they are arranged.
5. The security element according to at least one of claims 1 to 4, characterized in that the support structures comprise support columns having a circular, oval, triangular, rectangular or polygonal cross section, and in which the cross section of the support columns preferably has a surface area between 0.25 µm² and 25 µm².
6. The security element according to at least one of claims 1 to 5, characterized in that the support structures comprise continuous, irregularly running ridge structures in which the width of the ridge structures is preferably between 0.1 µm and 5 µm.
7. The security element according to at least one of claims 1 to 6, characterized in that the support structures comprise non-continuous ridge elements that each consist of one or more line fragments and whose width is preferably between 0.1 µm and 5 µm.
8. The security element according to at least one of claims 1 to 7, characterized in that the support structures comprise straight, parallel ridge elements whose width is preferably between 0.1 µm and 5 µm.
9. The security element according to at least one of claims 1 to 8, characterized in that the support structures include, in a sub-region, a hidden piece of information in the form of characters or a code.
10. The security element according to at least one of claims 1 to 9, characterized in that the viewing elements are formed by spherical lenses, aspherical lenses, cylindrical lenses or one- or two-dimensional focusing concave microreflectors, or in that the viewing elements are formed by cylindrical lenses and the support structures are formed by parallel, straight ridge elements that extend in an angle between 60° and 120°, preferably between 85° and 95°, particularly preferably of 90° to the axis of the cylindrical lenses.
11. The security element according to at least one of claims 1 to 10, characterized in that the display arrangement is an alternating image, a motion image, a pump image, a morph image or a stereo image, or in that the display arrangement is a micro-optical display arrangement, especially a moire magnification arrangement, a moire-type magnification arrangement or a modulo magnification arrangement.
12. The security element according to at least one of claims 1 to 11, characterized in that an additional patterning, preferably a diffractive pattern, a pattern having a mattifying or scattering effect, and/or a nanopatterning, is introduced into the depressions in the embossing pattern.
13. The security element according to at least one of claims 1 to 12, characterized in that the motif layer is provided, contiguously or on part of the surface, with at least one printing ink and/or with at least one reflective coating material, preferably a metal, a color-shifting system, a high-index material, metal pigments or effect pigments.
14. A data carrier having a security element according to one of claims 1 to 13.
15. A method for manufacturing a security element having a display arrangement for displaying one or more target images whose motifs are each formed by visually perceptible, contrasting metallic and non-metallic sub-regions, having the following method steps:

    (a) manufacturing a donor foil (50) by

    (i) forming an embossing pattern having elevations and depressions and having, arranged in the depressions in an area fraction of between 0.1% and 25%, elevated support structures, at least in a sub-region of a main surface of a first foil material, or in an embossable layer on at least one sub-region of a main surface of a first foil material,
    the elevations and the depressions producing image elements of a motif layer of the display arrangement, which image elements produce visually perceptible, contrasting metallic and non-metallic sub-regions of the target images when the motif layer is viewed with a viewing grid of the display arrangement,

    (ii) applying a metal coating (48) at least to a sub-region of the embossing pattern,

    (b) manufacturing an acceptor foil (52) by applying an adhesive layer (56) at least to a sub-region of a main surface of a second foil material,

    (c) laminating the donor foil and the acceptor foil by means of the adhesive layer in such a way that at least one sub-region of the coated embossing pattern and one sub-region of the adhesive layer come into contact with each other, the metal coating on the elevations in the embossing pattern adhering in the contact region with the adhesive layer of the acceptor foil,

    (d1) transferring the metal coating that is present in the contact region on the elevations in the donor foil to the adhesive layer of the acceptor foil by separating the donor foil and the acceptor foil, through which a motif layer having a plurality of metalized image elements and non-metalized image elements is created from the donor foil, and

    (e1) manufacturing a display arrangement by combining the motif layer of the donor foil with a viewing grid, composed of a plurality of viewing elements, in such a way that the metalized image elements and the non-metalized image elements produce the visually perceptible, contrasting metallic and non-metallic sub-regions of the target images when viewed with the viewing grid.
16. The method according to claim 15, characterized in that, in step (a), an additional patterning, preferably a diffractive pattern, a pattern having a mattifying or scattering effect, and/or a nanopatterning, is introduced into the depressions in the embossing pattern.
17. A method for manufacturing a security element having a display arrangement for displaying one or more target images whose motifs are each formed by visually perceptible, contrasting metallic and non-metallic sub-regions, having the following method steps:

    (a) manufacturing a donor foil (50) by

    (i) forming an embossing pattern having elevations and depressions and having, arranged in the depressions in an area fraction of between 0.1 % and 25%, elevated support structures, at least in a sub-region of a main surface of a first foil material, or in an embossable layer on at least one sub-region of a main surface of a first foil material,
    the elevations and the depressions producing image elements of a motif layer of the display arrangement, which image elements produce visually perceptible, contrasting metallic and non-metallic sub-regions of the target images when the motif layer is viewed with a viewing grid of the display arrangement,

    (ii) applying a metal coating (48) at least to a sub-region of the embossing pattern,

    (b) manufacturing an acceptor foil (52) by applying an adhesive layer (56) at least to a sub-region of a main surface of a second foil material,

    (c) laminating the donor foil and the acceptor foil by means of the adhesive layer in such a way that at least one sub-region of the coated embossing pattern and one sub-region of the adhesive layer come into contact with each other, the metal coating on the elevations in the embossing pattern adhering in the contact region with the adhesive layer of the acceptor foil,

    (d2) transferring the metal coating present in the contact region on the elevations in the donor foil to the adhesive layer of the acceptor foil by separating the donor foil and the acceptor foil, through which a motif layer having a plurality of metalized image elements and non-metalized image elements is created from the acceptor foil, and

    (e2) manufacturing a display arrangement by combining the motif layer of the acceptor foil with a viewing grid, composed of a plurality of viewing elements, in such a way that the metalized image elements and the non-metalized image elements produce the visually perceptible, contrasting metallic and non-metallic sub-regions of the target images when viewed with the viewing grid.
18. The method according to at least one of claims 15 to 17, characterized in that, in step (d1) or in step (d2), also the metal coating present in the contact region on the elevated support structures in the donor foil is transferred to the adhesive layer of the acceptor foil by separating the donor foil and the acceptor foil.
19. The method according to at least one of claims 15 to 18, characterized in that, before step (a)(ii), in at least one sub-region of the embossing pattern, an adhesion-reduction treatment of the embossing pattern is carried out, and/or in that, after step (d1) or after step (d2), the motif layer is provided, contiguously or on part of the surface, with at least one printing ink and/or with at least one reflective coating material, preferably a metal, a color-shifting system, a high-index material, metal pigments or effect pigments.

Images