HK1190991B - Optically variable element, data carrier, and method for manufacturing optically variable element - Google Patents

Description

Optically variable element, data carrier and method for producing an optically variable element

Technical Field

The invention relates to an optically variable element, in particular a security element for a data carrier.

Background

Data carriers, such as value goods, identity documents or value goods (such as branded goods), usually have optically variable elements for security purposes which allow the authenticity of the data carrier to be verified, while at the same time protecting it against unauthorized copying. For this reason, the optical effect of the optically variable element changes when, for example, the viewing direction changes and cannot be reproduced by a conventional copying machine.

Disclosure of Invention

The invention is based on the object of specifying an optically variable element, in particular a security element for data carriers, which combines high forgery resistance with good legibility and simple verifiability.

This object is achieved by an optically variable element, in particular a security element for a data carrier, having a substrate with a pattern-forming section having a first partial region and a second partial region, the first partial region being produced by means of intaglio printing and the second partial region not being produced by means of intaglio printing, wherein the two partial regions are respectively perceptible as being optically protruding and/or retracting, the optically perceptible imprint and the tactilely detectable imprint of the first partial region matching, and the optically perceptible imprint and the tactilely detectable imprint of the second partial region not matching.

Thus, an optically variable element is provided which is optically very attractive due to the optical protrusion and/or retraction of the partial areas, wherein surprisingly the tactilely detectable imprint matches the optically perceptible imprint only for the first partial area and not for the second partial area. The variation of the tactile or tactile perception of the patterned portion results in a high identification value and results in a simple verification of the authenticity of the optically variable element.

The partial regions which are perceived as optically protruding and/or retracting are to be understood here in particular as meaning regions which are perceived as continuously protruding. Thus, the partial regions can be optically perceived as having a projection which deviates from the curve or actual spatial shape of the reflective layer in the region of the respective partial region. In particular in the case of the second partial region, a correspondingly convex surface can be simulated, for example, by imitating a corresponding reflection behavior.

The two partial regions can each be configured as a continuous region. However, the partial regions may also have gaps or even comprise discontinuous portions. In particular, the two partial regions may be interlaced with each other and/or with other security features.

Also, one of the two partial regions may surround the other of the two partial regions.

In the optically variable element, the pattern forming part in the second partial region may have a plurality of facets oriented to a viewer such that there are regions which are optically perceivable as protruding and/or receding relative to the macro-spatial shape of the pattern forming part of the second partial region. In the case of the second partial region, the actual convex surface (reflection and/or transmission) can thus be simulated. In the case of the second partial region, however, it is also possible to imitate the surface form, the reflection behavior of which cannot be caused with a real convex surface. Such an area is hereinafter referred to as "imaginary area". Such an imaginary area may be perceived as a rotating mirror, for example, which rotates the visible mirror image by, for example, 90 °. It is very easy for a viewer to optically detect and verify such imaginary areas and in particular such rotating mirrors.

In principle, any actual convex reflective or transmissive surface can be modified into an imaginary area by means of the second partial area of the optically variable element according to the invention. This can be achieved, for example, by changing the azimuth angle (e.g., rotating by a certain angle) of all facets. This can achieve an attractive effect. For example, if all azimuth angles are rotated 45 ° to the right, the imaginary area is a convex area that is apparently illuminated from the top right of the viewer when illuminated directly from above. If all azimuth angles are rotated by 90 deg., the light reflection moves while being tilted in a direction perpendicular to the direction desired by the viewer. This unnatural reflective behavior also makes it no longer certain to the viewer whether the convex perceptible area is facing forward or backward (relative to the substrate), for example.

Moreover, in the optically variable element of the invention, the orientation of the facets can be changed with respect to the orientation of the perceptible area for producing the protrusion and/or retraction to the perceptible area for protrusion and/or retraction which is still perceptible, but has a matte surface appearance. In this way, a sparkle effect may be created.

To produce such a matte or shiny surface one can proceed as follows: the orientation of the facets is changed by arbitrarily deviating from the specified target orientation within certain limits. In particular, several adjacent facets may each also deviate from the target orientation by the same arbitrary degree of deviation. Depending on the amount of any deviation, the amount or number of facets, respectively, having the same deviation, it is thus possible, for example, to produce a matte surface appearance or a sparkling surface, i.e. a surface with a sparkling effect. Optically variable elements having such a matte surface or a surface which is perceived as sparkling have a very high recognition value and thus a very high resistance to forgery.

Moreover, the facets may be configured as achromatic facets. This is to be understood in particular as meaning that the reflection behavior of the component surfaces is caused by, or at least controlled by, the ray-optical effect. The facets thus do not act as diffractive structures or act only very rarely as diffractive structures.

In the optically variable element, the maximum impression depth of the intaglio printing in the first partial region may be equal to at least 20 μm, preferably equal to at least 40 μm, particularly preferably equal to at least 70 μm. Such a depth of impression can be detected tactually very well.

Furthermore, in the optically variable element, the maximum height difference of the relief structure (reliefstructure) in the region of the second portion may be less than 15 μm, preferably less than 10 μm, particularly preferably less than 5 μm. This maximum height difference is so low that it cannot be detected by touch or is only difficult to detect by touch (then typically unstructured roughness).

In the optically variable element, the second partial region can exhibit an optical difference in height, the actual structural height present in the second partial region being at least 1/3, preferably 1/5, particularly preferably 1/10, of its optically apparent height. It is thus ensured that the optically perceivable and the tactilely detectable imprint of the second part-area does not match.

In particular, the optically variable element may be configured such that the second partial region is flat to the touch.

In the case of an optically variable element, the first subregion can be produced, in particular, by means of stamping. Furthermore, the first partial region can be formed by pixel embossing on a bottom surface which looks like metal, which is color-shifted and/or glittering.

In the optically variable element, the first partial region may be reflective.

The optically variable element can be constructed such that the two partial regions exhibit the same relief representation (reliefrepresentation), meaning-dependent patterns, continuous patterns and/or combined patterns. For example, the first partial region may present a tactilely tactile bow and the second partial region may present a seemingly convex but tactilely untouchable piano (violin). The two part-areas may together also present a pattern like a piano, while only a part of the pattern of the first part-area may be tactilely detectable in conformity with the optically perceivable impression.

Furthermore, the first partial region can be at least partially embossed on the second partial region by means of intaglio printing, for example. As such, deliberate destruction (imprint loss) may be desirable, for example, in the second partial region, so that the first partial region is optically located virtually in front of the second partial region, for example, is not translucent.

In the optically variable element, the second partial region can have a microstructure which simulates the reflection and/or refraction behavior of the convex surface. The microstructure may be at least one element of the following group: fresnel structures, reflective sawtooth gratings or facets, diffraction elements for projecting simulations (e.g. active designs), moir é amplifiers and analog-to-digital converters, in particular microstructures with metallization. Active design is understood here to mean, in particular, the presence of an appearance which is dependent on the viewing angle, with a visible movement effect being produced when the viewing angle is changed. Such an example is described, for example, in WO2007/107235A 1.

The microstructures may be embossed in the embossing lacquer. In particular, there may also be a reflective or reflection enhancing coating, especially a metallized color shifting coating (the perceived color depends on the viewing angle), a high refractive index coating and/or a coating comprising ink with a reflective pigment plate in the microstructure such that the pigment plate is aligned substantially parallel to the micro relief.

The second partial region can be transparent. Also, it may have a partially transmissive coating (e.g., a grid or very thin metal) and/or a color shifting coating in plan-view and/or perspective. Metallization patterns beside the demetallized regions may also be provided.

In particular, the optically variable element can be configured as a security thread, tear thread, security tape, security strip, color code or marking for application to security paper, value documents or the like. In particular, the optically variable element may span a transparent or at least translucent region or recess.

In particular, the term security paper is understood to mean a precursor part of a document of value, which is not readily circulated, but which may, for example, have, in addition to the optically variable element according to the invention, further authenticity features, such as, for example, luminescent substances arranged in the volume. On the one hand, a document of value is understood here to be a document made of security paper. On the other hand, the value documents can also be other documents and objects having the optically variable element according to the invention, in order to provide the value documents with an irreproducible authenticity feature, so that the authenticity can be checked while preventing undesired copying.

A data carrier with an optically variable element of the invention (including all the above-mentioned developments of the optically variable element of the invention) is also provided. The data carrier may be a value, an identity document, security paper or other value.

There is also provided a method of manufacturing the optically variable element of the invention (including its development), wherein the first partial region is produced by means of intaglio printing and the second partial region is not produced by means of intaglio printing.

For the optically variable element and/or the substrate of the data carrier, such as a banknote, plastic materials can be used as the material. In particular, it may also be paper-based.

Thus, paper with rayon (i.e. paper with a polymeric material having a content x in the range of 0< x <100 wt%), plastic foils (e.g. foils of Polyethylene (PE), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polypropylene (PP) or Polyamide (PA)) or multilayer composites, in particular composites of several different foils (compound composites) or paper foil composites (foil/paper/foil or paper/foil/paper) may be used. The optically variable element may be disposed in, on or between any of the layers of such a multilayer composite.

It is clear that the features mentioned above and those to be explained below can be used not only in the combination described but also in other combinations or in isolation, without going beyond the scope of the present invention.

Drawings

The invention will be described more precisely hereinafter by way of example with reference to the accompanying drawings, which also disclose features essential to the invention. For greater clarity, the drawings are not drawn to scale or precisely, and in which:

figure 1 is a plan view of a banknote having an optically variable element 1 according to the present invention;

FIG. 2 is an enlarged cross-sectional view of optically variable element 1 along section line D-D of FIG. 1;

FIG. 3 is a cross-sectional view of an optically variable element of another embodiment;

FIG. 4 is a plan view of another embodiment of an optically variable element of the present invention;

FIG. 5 is a plan view of another embodiment of the variable element of the present invention; and

FIG. 6 is a plan view of another embodiment of an optically variable element of the present invention.

Detailed Description

In the embodiment shown in fig. 1, the optically variable element 1 according to the invention is applied to the front side of the banknote 2 shown in fig. 1 and serves as a security element or security feature, so that the authenticity of the banknote 2 can be checked.

The optically variable element or security element 1 is designed as a reflective security element 1 with a rectangular outer contour and has a design 3 (here a letter set AB), the design 3 having a first partial region 4(a) and a second partial region 5 (B).

As is most clearly seen in fig. 2, in which the security element 1 is schematically shown in cross-section along the sectional line D-D, the security element 1 comprises a substrate 6, the substrate 6 having a reflective layer 7 in the first partial region 4. The upper side of the reflective layer 7 facing away from the substrate 6 is embossed by means of a gravure printing process and thus has a surface structure.

The surface structure in the first subregion 4 is here selected such that the letter a is optically perceptible as protruding relative to the substrate 6. The height or impression depth d1 and the transverse dimensions of the elevations 8 are selected such that the tactilely detectable print matches the optical print. Whereby one notices the raised letter a when rubbing the first partial area 4 with a finger.

The maximum height d1 of the elevations 8 may, for example, be equal to 80 μm, and the progression of the heights is preferably continuous. In this case, a particularly good tactile sensation is exhibited.

The layer 7 can be configured not only as a metallic layer but also as a metal-like layer, which is applied by means of a printing technique (for example by screen printing, flexography, indirect letterpress, offset printing or inkjet), so that after intaglio printing the first partial region 4 can be perceived as an optically coin-like metal-like relief.

In addition to inks with simple metallic pigments, optically variable inks may alternatively be used. It is also possible to combine different inks with each other so that, for example, the embossed first partial region 4 appears colored.

In the second subregion 5, a plurality of reflective facets 12, which are arranged, for example, on the substrate 6, can be formed in the lacquer layer 11. The reflective facets 12 are arranged and oriented such that they mimic, for the viewer, a reflective area 13 which appears to be convex with respect to the actual macroscopic spatial shape of the lacquer layer 11 or the substrate 6. In the embodiment described, the reflection area 13 is the letter B, the reflection area 13 being indicated by a dashed line in the sectional view of fig. 2.

The optical effect mimicking the reflective area 13 is achieved by the fact that the inclinations of the facets 12 are selected according to their lateral position such that incident light is reflected on the facets 12 in the same direction as the convex area 13 would reflect light. Thus, incident light beam 15 is reflected in a direction 16 parallel to direction 16 ', which direction 16' corresponds to the direction of reflection on surface 13. The same applies to the beams 17 and 19 reflected in the directions 18 and 20. These directions 18 and 20 are parallel to the directions 18 'and 20', the directions 18 'and 20' being the reflection directions upon reflection on the surface 13.

The maximum height d2 and the maximum dimension of facet 12 are preferably selected such that the facet 12 cannot be discerned by the naked eye of an observer. The preferred embodiment shown in fig. 2 has facets 12 arranged periodically with a substantially constant periodicity. The facets 12 of this embodiment also have a height that varies in the lateral direction.

The viewer therefore derives from the reflection behavior of the second subregion 5 that, in the second subregion 5, the projection regions 13 have a height d3, which is d3 is significantly greater than the maximum height d2 of the facets 12 and approximately corresponds to the height d1 of the elevations 8 located in the first subregion 4.

Thus, for example, in the case of the light beam 15, the reflection behavior indicates a local surface normal pointing direction 21, which is clearly different from the macroscopic surface normal (arrow 22) of the lacquer layer 11. In the second partial region 5, a projection is simulated by directional reflection at the facets 12, so that only an indirect depth impression or 3D impression is obtained. The stamp may also be designated as "2¹/₂"size representation or relief representation.

Due to the small dimensions of the individual facets 12, the tactilely detectable print of the second partial region 5 is clearly different from the optically perceptible print. Therefore, due to the optical imprint, the viewer desires a region protruding forward. However, when touching the second partial area 5, he will touch or notice only a substantially plane area.

Thus, although in the first part-area 4 the optically perceivable print matches the tactile perception, in the second part-area 5 the optically perceivable print deviates from the tactilely detectable print. The security element 1 according to the invention can therefore advantageously be checked simply and uniquely for users without additional aids.

The maximum height d2 of the facets may be less than 15 μm. Preferably, it is less than 10 μm, in particular, it is less than 5 μm.

The original facets 12 as photoresist can be exposed, for example by means of grey-scale lithography known from the prior art, electroformed and subsequently embossed, for example in a radiation-curable lacquer and/or a thermoplastic lacquer 11.

The lacquer 11 may, for example, be applied directly on the substrate 6 or, however, may be provided on a foil strip, in particular a laminate strip or a transfer strip, and from there subsequently transferred to the substrate.

To enhance the reflectivity of facet 12, the facet may be provided with a reflection enhancing coating. They may be, for example, metallized.

The coating on facet 12 may also be color-shifting at least in certain areas, for example by applying a suitable liquid crystal or vapor coating using a reflector/dielectric/absorber film system.

In fig. 3, a cross-sectional view of an alternative embodiment is shown, in which facet 12 is made at least partially transparent and is located, for example, in a window area 25 of substrate 6, which substrate 6 may be the substrate of a banknote.

In the perspective view, the facet 12 has the effect that the incident light 15 is refracted, for example, in the direction 16, in which direction 16 also the incident light 15' is refracted by the protruding objects corresponding to the curve 26 and having the same refractive index. The second partial region 5 thus resembles a lenticular object with a surface relief according to the curve 26.

In this embodiment, too, the relief in the first partial region 4 is distinctly tactile according to the invention. In the second partial region 5, however, the lenticular relief becomes a thin foil, wherein the visually detectable elevations are not accessible.

In addition to the configuration of the transparent facets 12, reflective facets may also be used in the window area 25 as in the first embodiment. Preferably, the area surrounding facet 12 may be demetallized.

Furthermore, facets 12 may also have a translucent coating (e.g., a grid or a very thin metal, and especially also a partially transmissive color shifting coating).

Of course, instead of facets 12 described above, any relief simulation may be used in which the optically perceptible print and the tactilely detectable print do not match. Thus, for example, fresnel structures, diffractive structures and moir é amplifiers or analog-to-digital converters, in particular microstructures with metallization, can be used.

The corresponding structures may be embossed, but not by means of intaglio printing. Preferably, the radiation-cured or thermoplastic lacquer 11 is embossed. Lacquer 11 may be applied directly to substrate 6. The lacquer 11 may also be applied on a foil which is subsequently attached to the substrate 6. Alternatively, the lacquer 11 may be present on a transfer foil from which the structure is transferred to the substrate 6 in a known manner. The substrate 6 may also be directly embossed.

Furthermore, the microstructure of the second partial region 5 can be located in a multilayer structure. The microstructure may thus for example be located on the inner side of the outer foil and thus be better protected from external influences. For example, the microstructure forming the second partial region 5 can be configured between two outer foils of a plastic banknote or between a paper layer and a foil layer of a hybrid banknote. In particular, the entire carrier core of the substrate 6 may comprise microstructures forming the second partial region 5, which microstructures are protected by the cover foil.

In the exemplary embodiment described so far, the two partial regions 4,5 (here the letters a and B) are spaced apart. In fig. 4, a further example of an arrangement of two partial regions 4,5 is shown. The embossing relief of the first partial region 4 (here in the form of the letter a) is surrounded by a second partial region 5 which has only a convex appearance, the partial region 5 having the form of a convex ring which has, for example, the letter B in the convex appearance.

In the embodiment shown in fig. 5, the actually protruding pattern a (first partial area 4) is located in front of a background with a plurality of letters B having only a protruding appearance (second partial area 5). The pattern B can be, for example, a lake of relief appearance (formed by facets under a microscope), and the pattern a can be, for example, a boat, which is embossed by intaglio printing on the second partial region (letter B). Here, there is a deliberate destruction (imprint loss) in the second partial region 5. Thus, the boat may be, for example, on water and not appear translucent.

In the embodiment shown in fig. 6, the two partial regions 4,5 border directly one another.

Parts list

1 optically variable element

2 banknote

3 pattern

4 first partial region

5 second partial region

6 base

7 reflective layer

8 bump

11 paint layer

12 fen noodle

13 reflective area

15 incident light beam

16 directions

16' direction

17 incident light beam

18 direction

18' direction

19 incident light beam

20 direction

20' direction

25 window area

26 curve

Height d1

Height d1

Height d3

Claims (27)

1. An optically variable element having:

a substrate (6) having a pattern forming portion having a first partial area (4) made by gravure printing and a second partial area (5) not made by gravure printing,

wherein the two partial regions (4,5) can be respectively perceived as optically protruding and/or retracting,

the optically perceptible print and the tactilely detectable print of the first partial area (4) are matched, and

the optically perceptible imprint and the tactilely detectable imprint of the second part-area (5) do not match,

wherein the two partial areas (4,5) exhibit the same relief representation, meaning-dependent patterns, continuous patterns and/or combined patterns.

2. The optically variable element as claimed in claim 1, wherein the pattern-forming part located in the second partial region (5) has a plurality of facets (12) which are oriented to a viewer in such a way that there are regions (13) which are perceivable to be optically protruding and/or receding relative to the macroscopic spatial shape of the pattern-forming part (7) of the second partial region.

3. An optically variable element as claimed in claim 2, wherein the orientation of the facets (12) is changed relative to the orientation used to form the protruding and/or retracted regions to such an orientation that the protruding and/or retracted regions are still perceptible, but have a matte surface and/or a sparkling appearance.

4. An optically variable element as claimed in claim 2 or 3, wherein the facets (12) are oriented such that the second partial regions (5) exhibit a reflection behavior which cannot be caused with a virtually macroscopically convex reflection surface.

5. An optically variable element as claimed in claim 1, 2 or 3, wherein the second partial region (5) is transmissive.

6. An optically variable element as claimed in claim 1, 2 or 3, wherein the maximum depth of indentation in the first partial region is equal to at least 20 μm.

7. An optically variable element as claimed in claim 1, 2 or 3, wherein the maximum depth of indentation in the first partial region is equal to at least 40 μm.

8. An optically variable element as claimed in claim 1, 2 or 3, wherein the maximum depth of indentation in the first partial region is equal to at least 70 μm.

9. An optically variable element as claimed in claim 1, 2 or 3, wherein the maximum height difference of the relief structures in the second partial region (5) is less than 15 μm.

10. The optically variable element according to claim 9, wherein the maximum height difference of the relief structure in the second partial region (5) is less than 10 μm.

11. The optically variable element according to claim 10, wherein the maximum height difference of the relief structure in the second partial region (5) is less than 5 μm.

12. An optically variable element as claimed in claim 1, 2 or 3, wherein the second partial region exhibits an optical height difference, wherein the actual existing structure height in the second partial region is at least 1/3 of the optically apparent height.

13. An optically variable element as claimed in claim 1, 2 or 3, wherein the second partial region exhibits an optical height difference, wherein the actual existing structure height in the second partial region is the optically apparent height 1/5.

14. An optically variable element as claimed in claim 1, 2 or 3, wherein the second partial region exhibits an optical height difference, wherein the actual existing structure height in the second partial region is the optically apparent height 1/10.

15. An optically variable element as claimed in claim 1, 2 or 3, wherein the optically perceivable height difference of the two partial regions (4,5) is the same.

16. An optically variable element as claimed in claim 1, 2 or 3, wherein the second partial region (5) is flat to the touch.

17. An optically variable element as claimed in claim 1, 2 or 3, wherein the first partial region (4) is produced by means of stamping.

18. The optically variable element according to claim 1, 2 or 3, wherein the first partial region (4) is formed by means of a primordial imprint on a metal-like base surface, which is color-shifted and/or glittering.

19. An optically variable element as claimed in claim 1, 2 or 3, wherein the first partial region (4) is reflective.

20. The optically variable element according to claim 1, 2 or 3, wherein the first partial region (4) is at least partially embossed on the second partial region (5) by gravure printing.

21. The optically variable element according to claim 1, wherein the second subregion (5) has a microstructure which simulates the reflection and/or refraction behavior of a convex surface.

22. The optically variable element of claim 21, wherein the microstructure is at least one element from the group consisting of: fresnel structures, reflective sawtooth gratings or facets, diffraction elements for projecting simulations, moir é amplifiers, analog-to-digital converters.

23. The optically variable element of claim 21 or 22, wherein the microstructures are metallized.

24. An optically variable element as claimed in claim 1, 2 or 3, wherein the second partial region has a colour-shifting coating.

25. The optically variable element as claimed in claim 1, wherein the optically variable element is a security element for a data carrier.

26. A data carrier having an optically variable element as claimed in any preceding claim.

27. A method of manufacturing an optically variable element according to any of claims 1 to 25, wherein the first partial region is made by gravure printing and the second partial region is not made by gravure printing.