HK1172587B - Data carrier having a window - Google Patents

Abstract

The present invention relates to a data carrier, particularly a valuable or secure document, comprising a window (14) extending from the bottom surface (16) to the top surface (18) of the data carrier and a foil element (20) having a security element (22) covering the window (14) on the top surface (18) of the data carrier, a portion of the security element (22) being located on the window (14), and a portion of the security element (22) being close to the window (14).Here, according to the present invention, the portion of the security element (22) located on the window (14) has a radiation modified region (24) aligned with the window (14) and in which the appearance of the security element (22) is altered under the action of electromagnetic radiation.

Description

Data carrier with a window

Technical Field

The invention relates to a data carrier, in particular a value or security document, comprising a window extending from the bottom of the data carrier to the top of the data carrier and having a foil element with a security element covering the window at the top of the data carrier, a part of the data carrier being located above the window and a part of the data carrier being located close to the window.

Background

For protection purposes, security or value documents, such as banknotes, identity cards and the like, are often provided with security elements which allow the authenticity of the document to be verified, while preventing it from being copied without authorization. Here, transparent security features, such as transparent windows in banknotes, are becoming more and more interesting. Here, for the purpose of making a window, a foil is applied to the banknote to close a pre-formed through hole in the banknote, the foil being provided with an adhesive layer on one side.

The application of the foil to the banknote is subject to unavoidable alignment tolerances on the banknote, so that the security element of the foil, which is particularly adapted to the through-hole, cannot be perfectly aligned with the through-hole. The alignment tolerances have to be taken into account when designing the security element, which limits the freedom of design creation.

Disclosure of Invention

To this end, the invention aims to provide a data carrier of the above-mentioned type, in particular to facilitate a security element having a design which is highly aligned with the window, so that an attractive visual appearance can be combined with high security properties.

This object is achieved by a data carrier having the features of the independent claim. A method of manufacturing such a data carrier is defined in the respective claims. The novel concepts of the present invention are the subject of the dependent claims.

According to the invention, in a typical data carrier, the part of the security element situated above the window has a radiation-modified region which is aligned with the window and in which the visual appearance of the security element can be changed under the action of electromagnetic radiation.

The invention is here based on the idea of allowing alignment tolerances between the security element of the foil element to be applied and the window of the data carrier, but of aligning the modification region with the window in order to modify the visual appearance of the security element in the modification region by the action of radiation, in particular laser irradiation. When viewed, the difference in alignment between the foil element and the window becomes largely or completely less important, whereas the complete alignment of the window and the modified area dominates the visual impression of the viewer.

Since the window and the modified zone are precisely aligned with each other, the visual appearance and/or the information content of the two elements can also be coordinated or correlated with each other. For example, the window and the modified region may depict the same pattern or may each depict only pattern portions that complement each other to form a complete pattern. This visual or content-related interaction increases on the one hand the attention and identification value of the protection and on the other hand the anti-counterfeiting performance, since the manufacture of security features, such as windows and modified areas in the content, which are associated with each other, constitutes a higher technical barrier than the manufacture of security features, which are independent or not associated with each other, in the two contents.

The window for the data may be formed by a through hole extending from a bottom surface of the data carrier to a top surface of the data carrier. The window can also be formed by a transparent area of the data carrier, which is transparent, for example an unprinted area of a plastic banknote. In the case of a multilayer data carrier, the window can also be formed by a combination of a transparent region of the first data carrier layer of the composite banknote, a through-opening of the second data carrier layer (e.g. a paper layer) and an ink-absorbing layer which is not completely transparent.

In an advantageous variant of the invention, the security element has a metal layer which is demetallized in the radiation modification region. Demetallization is understood here to mean the burning off or the becoming transparent of the metal layer. The metal layer may be fully demetallised, in other words completely removed or completely rendered transparent, or it may be only partially demetallised to produce modified regions which are still translucent (in particular 20% to 80% transparency). As will be explained in more detail below, the metal layer can also be demetallized in the region of the through-holes only in certain regions, so that the radiation-modified regions in the region of the through-holes produce a sub-pattern which is perfectly aligned with the through-holes.

The security element comprises, inter alia, a metallized diffractive pattern, a metallized blazed diffractive pattern, a metallized matte pattern or a thin-film element with a color-shifting effect, which thin-film element usually consists of a metallic reflective layer, a dielectric spacer layer and an absorbing layer. In addition, other security elements with a metallization structure, such as metallized concave micromirrors, are also conceivable.

In an advantageous variant of the invention, the security element has a partial region and a second partial region, which interact differently with the electromagnetic radiation. The first and second subsection regions are located partially above and partially adjacent to the window. Here, the different interactions are in different degrees or different interaction types.

For example, different degrees of interaction may lead to demetallization of only the first sub-region in a metallized security element, or to a color change of only the first sub-region or also to a strong color change of said first sub-region in a radiation-colored or radiation-decolored security element. In different degrees of interaction, the two fractional regions react in substantially the same way, but one fractional region reacts more than the other, which reacts less strongly or not at all.

In contrast, for different types of interaction, both subsection areas react under the influence of radiation, but in a different manner. For example, the colourless area of the radiation-coloured security element may turn red in the first partial area and blue in the second partial area. Also in this way, a different visual appearance can be obtained in the modified zone.

In an advantageous embodiment, the radiation modified region comprises only a first partial region and no second partial region, such that the second partial region shows the same visual appearance above and close to the window.

In a preferred embodiment, in order to obtain different degrees of interaction, at least one of the two partial areas has an interference pattern, in particular a relief pattern in the form of a grating pattern which is determined by a grating constant and a grating groove direction. The second subregion may not comprise a relief pattern or a relief pattern in the form of a grating pattern defined by a second grating constant and a second grating ruling direction. The second grating constant and/or the second grating line direction of the second division area is different from the first grating constant or the first grating line direction of the first division area. The grating pattern of the second sub-area may also have the same grating constant and grating ruling direction as the grating pattern of the first sub-area, but inclined at an angle to the first grating pattern, e.g. arranged on each side of the sawtooth structure.

Material ablation occurs with the help of the grating pattern, which shows enhanced absorption properties. The enhanced light absorption properties can be explained by resonance excitation (surface plasmons or cavity resonances) of metals. For this purpose, the grating constant is selected to be on the order of the wavelength of the laser light used for the radiation modification. The resonant light absorption at the grating is also largely dependent on the profile cross section, grating material, and surrounding material. The profile is therefore adapted to the wavelength of the laser used to achieve high absorption properties. For example, gratings with different groove depths in the lateral direction exhibit different absorption properties in the lateral direction. In a preferred embodiment, the first subregion comprises a grating pattern with as high an absorption as possible, while the second subregion does not have a grating pattern. Due to the coordinated wavelength, angle of incidence and polarization, the incident laser radiation causes demetallization of the grating regions.

In particular, the second direction of the grating lines may be substantially perpendicular to the first direction to obtain a different interaction of the partial areas with linearly polarized electromagnetic radiation. In a preferred embodiment, the two partial areas have grating patterns with a grating constant of 750 to-1,050 nm, preferably about 900nm, and the grating patterns have different grating groove directions.

Other possibilities for creating different interactions for two subareas filled with grating patterns are mainly to use grating patterns with different grating profiles in said first subarea and said second subarea. In a particularly preferred variant of the invention, the two partial regions interact with the polarized laser radiation to different extents, since a clear difference in the extent of interaction is readily obtainable. In a new concept of the invention, the two subdivision regions are formed by nested sub-regions. The subregions may in particular comprise parallel stripes, preferably parallel stripes having a stripe width of 10 μm to 50 μm.

In another embodiment with different interactive subsection regions, the first subsection region includes a surface-enlarging relief pattern, preferably a surface-enlarging relief pattern with intersecting sinusoidal surface topography. For example, the height of the surface topography may be 200 to 400nm, preferably 300nm, and the grating constants in the X and Y directions are 200 to 400nm, preferably about 300nm, respectively.

Further details regarding the selective removal of one of two or more subareas by irradiation with radiation are described in the patent publication WO2006/079489a1, the disclosure of which is incorporated by reference into the present specification.

In another possibility of a partial region producing different interactions, the first and second partial regions are formed by elevations and depressions of a relief pattern. In particular, it is possible to use,

-the support is provided with a relief pattern having elevations and depressions forming first and second regions having different first and second levels, the second regions of the relief pattern being in the form of a desired pattern,

-the relief pattern is metallized in succession with the first and second regions, and

-irradiating the metallized relief pattern with radiation to selectively remove the metal layer in the second areas of the relief pattern by the action of the radiation.

The radiation exposure may be generated with laser radiation.

Here, a laser beam absorbing covering layer and/or a laser beam reflecting covering layer filling the recessed portions of the relief pattern after metallization is preferably applied to the metallized relief pattern. In the selection of the cover layer, it is of utmost importance that very little laser radiation is transmitted in the recess region. Thus, the laser beam reflective coating layer may exhibit the same effect as or better than the laser beam absorptive coating layer. After filling, the cover layer is removed, in particular scraped off or wiped off, from the raised areas of the metallized relief pattern. Here, technically unavoidable, a thin tinting film (tint film) of the cover layer may remain on the raised areas of the metallized relief pattern. Such a cover layer comprises laser beam absorbing pigments or dyes or laser beam reflecting pigments or dyes, so that the cover layer can in turn be used as an ink layer to produce a design that is visible from the bottom. Further details of the cutting method based on a metallized relief pattern with projections and recesses and variants thereof are described in patent application PCT/EP2009/00882, the disclosure of which is included in the description of the present patent by reference.

The invention can be used particularly advantageously in micro-optical rendering devices, such as micro-optical moire magnification devices, micro-optical moire-type magnification devices and more generally mode magnification devices, which are described in particular in international patent applications WO2009/00528a1 and WO2006/087138a1, the disclosures of which are incorporated by reference in the present description. All these micro-optical magnification devices comprise a graphical image with a micro-pattern that reproduces a specific target image when viewed with a suitable coordinated viewing grid.

As described in detail in the publications and applications cited above, a number of visually appealing magnification and movement effects can be produced, resulting in the production of security elements with high identification value and high security properties. For example, the raster parameters of the graphics image and the viewing grid may be coordinated with each other such that when the rendering device is tilted, an orthogonal parallax (orthogonal) shift effect is produced, the first pattern being shifted perpendicular to the tilt direction instead of parallel to the tilt direction, as can be intuitively expected.

Here, in one variant of the invention, the security element comprises a micropattern having a line width of about 1 μm to 10 μm, the visual appearance of which is altered in the radiation-modified regions. Here, the micropattern advantageously forms a graphic image at least within the radiation-modifying region or at least outside the radiation-modifying region, which graphic image is subdivided into a plurality of cells, each cell being provided with an imaging region for a specific target image. Here, the lateral dimension of the imaging region is preferably about 5 μm to 50 μm, particularly 10 μm to 35 μm.

Furthermore, a viewing grid consisting of a plurality of viewing grid elements, preferably having a lateral dimension of about 5 μm to 50 μm, in particular 10 μm to 35 μm, is preferably used for reproducing the specific target image when the graphic image is viewed by means of the viewing grid.

The change in the radiation-modifiable area is for example a demetallisation of a metal layer, which makes the micropattern of the graphic image visible. In another variation, the micropattern is colored, the color of the micropattern being changed in the radiation modifiable area. Here, the first color may be changed to the second color by the radiation action. One of the two colours may also be transparent, in particular the first colour may be bleached by the action of radiation and thus become transparent, or the transparent areas may be coloured by the action of radiation and thus become coloured.

In an advantageous embodiment, the micro-patterns inside and outside the radiation-modified region each depict different figures, in particular different patterns, characters or codes. Variations between different patterns, characters or codes are perfectly aligned with the cut edge of the window.

For this purpose, the micropattern is advantageously provided in a two-coat lacquer system comprising two superimposed lacquer layers having substantially the same refractive index. Here, the lower paint layer is embossed with a second graphic image, and the upper paint layer provided on the lower paint layer is embossed with a first graphic image. In the radiation modified region, the upper paint layer is removed so that the second pattern of the lower paint layer within the radiation modified region and the first pattern of the upper paint layer outside the radiation modified region are visually recognizable.

In one variant of the present invention, the first,

-the security element comprises a plurality of retroreflective first micro graphic elements arranged regionally in a viewing element pattern and a permeable second micro graphic element arranged regionally in the viewing element pattern,

-the second micropattern element is located inside the radiation-modified region and the first micropattern element is located outside the radiation-modified region,

-the security element further comprises a micropattern object comprising a plurality of micropatterns arranged in a micropattern pattern that cooperates with the viewing element pattern such that the micropattern object is imaged magnified in front of the top by the first micropattern element, and

-an object plane located outside the security element, the object plane being assigned to the second micropattern element such that the micropattern of the micropattern object is unrecognizable when viewed from the bottom using the second micropattern element, but for verification a further micropattern object having a plurality of micropatterns may be located within the object plane area such that the further micropattern object is magnified imaged in front of the bottom by means of the second micropattern element.

Here, in particular, the first micropattern element is a concave micro-mirror and/or the second micropattern element is a microlens. Further details and advantages of such a combination of micro-lenses and concave micro-mirrors can be found in the german patent application DE102009022612.5, the content of which is incorporated in the present description by reference.

According to the invention, the shape of the window is not subject to any restrictions. In all embodiments it may particularly be in the form of a pattern or a character or a code. If the window is constituted by through-holes or if the window comprises through-holes, it is also particularly advantageous to use meshes (meshes), as described in german patent application DE102009011424.6, the content of which is incorporated by reference in the present application. The above-mentioned aligning effect is particularly pronounced if the through-holes are constructed from a wire grid consisting of a plurality of parallel cutting lines, because of the large number of transitions from the support to the through-holes.

In this specification, a through hole is generally taken as an example, but it can be seen from these examples that the through hole may include a plurality of portions, or may be a set of through holes.

Alternatively, the radiation-modified regions may be in the form of patterns, characters or codes, in addition to the windows. The pattern, characters or code of the radiation modified regions and windows are preferably identical or related, e.g. complementary to each other to form a complete pattern.

In a preferred idea the foil element is applied on top of the data carrier with a laser-ablatable adhesive layer, which is removed from the window area. In this way, a particularly clear visual appearance can be obtained in the window.

The invention also provides a method for manufacturing a data carrier, the method comprising:

a) providing a data carrier substrate and a foil element with a security element, the data carrier comprising a window extending from a bottom surface to a top surface of the data carrier substrate;

b) covering the window with the foil element on the top surface of the data carrier substrate in such a way that the security element is partly located on the window and partly close to the window; and

c) irradiating the security element with electromagnetic radiation through the window from the bottom surface of the data carrier substrate to change the visual appearance of the security element in a radiation modified region, the radiation modified region being located on the window.

Here, in step c), the security element is preferably irradiated with laser radiation, in particular ultraviolet radiation, visible radiation or near infrared radiation of a wavelength of up to 1.5 μm.

In step b) the foil element is applied to the top surface of the data carrier by means of a laser-ablatable adhesive, and in step c) the adhesive in the window area is removed by means of laser irradiation.

If the window is formed by a through hole or if the window comprises a through hole, then in step a) the through hole is formed in the data carrier substrate or the data carrier layer containing the through hole, preferably by means of a punch or laser cutting with a cutting laser, preferably with a laser having a wavelength of about 10.6 μm.

In the course of the production of the through-holes, the edges or the surrounding areas of the through-holes on the bottom of the data carrier substrate or the data carrier layer can be colored or altered in order to form through-holes on both sides of the data carrier or data carrier layer by means of an alignment effect. To this end, it is preferable, for this purpose,

-the data carrier substrate or the data carrier layer is provided with a laser variable marking substance at least around the through-hole to be produced;

-said through holes are formed in said data carrier substrate or said data carrier layer under the influence of laser radiation;

-the laser variable marking substance around the through hole is altered under the effect of the laser radiation.

Here, the marking substance may not only be changed in the region of the edge of the through-hole directly adjacent to the through-hole, but the laser-modified region may also be at a small distance from the through-hole. Preferably, the laser variable marking substance itself is modified by a cutting laser beam when the through-hole is made in the data carrier substrate. The fact that the laser energy in the outer region of the shape of the cutting laser beam is sufficient to change the marking substance (simultaneously with the laser cutting process) which is arranged at the edge region of the through-hole to be cut or in the vicinity of the through-hole is used to advantage. In this way, a perfect alignment of the through-hole and the edge region or adjacent region of the laser variation can be automatically ensured.

Alternatively or additionally, in the same operation, on the one hand, the through-hole can be formed in the support species at a higher laser energy by means of a laser module, and on the other hand, the laser variable marking substance in the vicinity of the through-hole can be changed at a lower laser energy. Since both steps are performed in the same operation, a highly accurate alignment of the vias and the laser modified adjacent areas can be achieved (deviation less than 0.4mm, in particular less than 0.2mm, or even less than 0.1 mm).

Further details and advantages of this method can be found in the patent document publication No. WO2009/003587a1, the content of which is incorporated by reference into the present specification.

The data carrier is in particular a value document, such as a banknote, in particular a paper banknote, a plastic banknote or a foil composite banknote, or an identification card, such as a credit card, a bank card, a cash card, an authorization card, a personal identification card or a passport personal page.

Drawings

Further preferred embodiments and advantages of the invention will be described hereinafter with reference to the accompanying drawings, in which drawings the depiction in scale and quantity is omitted for greater clarity. The different exemplary embodiments are not limited to use in the specifically described form but may also be used in combination with one another.

In the figure:

FIG. 1 is a schematic view of a banknote according to one embodiment of the present invention;

FIG. 2 is a cross-sectional view of the banknote of FIG. 1 taken along line II-II;

the sequence of fabrication of the content-based interfit visible between the through-hole and the hologram and an example are shown in figures 3(a) to 3 (c);

fig. 4(a) is a cross-sectional view of a security paper of the present invention, and fig. 4(b) and 4(c) are top or bottom plan views of a hologram or through-hole region, respectively, of the security paper;

fig. 5(a) -5(d) show intermediate steps in the manufacturing process of the security paper of the invention, wherein fig. 5(a) is a top view of the security element to be applied, fig. 5(b) is a top view of the security paper before the application of the security element, and fig. 5(c) and 5(d) are a top view and a cross-sectional view, respectively, of the completed security paper;

fig. 6(a) and 6(b) show intermediate steps in the manufacturing process of another security paper of the invention;

FIG. 7 is a top view of a security paper of one embodiment of the present invention;

FIG. 8 is a bottom view of a security paper of another embodiment of the present invention;

FIG. 9 is a cross-sectional view of a micro-optical delineation device of an embodiment of the invention;

FIG. 10 shows a moire magnification device having a micro-graphic element with a different color impression inside and outside the through-hole;

11(a) and 11(b) are a cross-sectional view and a top view, respectively, of a micro-optical rendering device of the present invention, the rendered graphic images varying at the cut edge of the through-hole;

fig. 12 and 13 show two embodiments of the present invention, which are formed based on a combination of microlenses and concave micromirrors.

Detailed Description

The invention will now be described by way of example with reference to banknotes. To this end, fig. 1 and 2 show a top view and a cross-sectional view, respectively, of a banknote 10, the banknote paper 12 of which banknote 10 is provided with a window in the form of a through hole 14, which through hole 14 extends from a bottom 16 to a top 18 of said banknote paper 12. On the top 18 of the banknote paper 12 the through hole 14 is covered by a foil strip 20.

Although the invention is described below by way of example in the context of a through-hole in a banknote, the invention is not limited to such an embodiment. The window of the data carrier can also be formed by a transparent region of the data carrier that is transparent, for example a transparent window of a polymer banknote. In a multilayer data carrier, the window can also be formed by a combination of a transparent region of the first data carrier layer and a through-opening of the second data carrier layer (for example a paper layer and a partially transparent ink-absorbing layer in a composite banknote).

The foil strip 20 in fig. 1 and 2 comprises a security element in the form of a metallised hologram 22, which hologram 22 is located partly over the through-hole 14 and partly adjacent to the through-hole 14. To this end, the hologram 22 typically has a larger area than the through-hole 14, and the foil strip 20 is applied to the banknote paper 12 in such a way that the hologram 22 completely covers the through-hole 14 and overlaps the area adjacent to the through-hole 14, as shown in fig. 1 and 2.

In this embodiment, the portion of the hologram 22 that is located over the via 14 forms a laser modified region 24, in which laser modified region 24 the visual appearance of the hologram 22 is modified by the action of laser radiation, and in accordance with the present invention, the laser modified region 24 is fully registered with the via 14.

This allows the patterns shown by the holograms 22, 24 to be aligned with the shape or profile of the via 14 without register changes, thereby creating a visual or content-based interfit between the via 14 and the hologram patterns 22, 24, as described below with reference to particular embodiments. Thus, the attention and the cognitive value of the holograms 22, 24 and their anti-counterfeiting properties are enhanced, since the complete alignment of the two elements, the through-hole 14 and the laser modified region 24, creates a significant barrier to potential counterfeiters.

The sequence of manufacturing and the first example of content-based interfitting visible between the through-hole and the hologram is described below in connection with the top views of fig. 3.

Referring to fig. 3(a), in the manufacturing process of the security paper of the present invention, first, a metallized hologram (e.g., a true color hologram 32) is provided on a foil strip 30, which includes, but is not limited to, a pattern having a mountain 34 and a sky 36 as schematically depicted in the figure. In addition, through holes 42 composed of a plurality of parts are formed in the security paper 40 by laser cutting, and the through holes 42 depict the sun with concentric rays as a pattern, as shown in fig. 3 (b). It is also possible to form simpler shapes in the security paper by punching instead of laser cutting.

The foil strip 30 with the hologram 32 is now applied on top 47 of the security paper 40 so that the through-hole 42 is located in the area of the sky 36 of the hologram 32. The foil element 30 is then irradiated with laser radiation (for example 1.064 μm pulsed neodymium Yack Nd: YAG laser radiation) from the bottom side of the security paper 40 through the through-hole 42, so that the metal layer of the hologram 32 in the region above the through-hole 42 is demetallized.

The demetallised regions of the hologram then form laser modified regions 38 in which the visual appearance of the hologram 32 is altered, as shown in figure 3 (c). Because the via hole 42 acts as a mask when demetallizing the hologram 32, the laser modified region 38 is perfectly aligned with the cut edge of the via hole 42.

The inevitable alignment tolerances (registration tolerance) when applying the foil element 30 onto the security paper 40 are not occupied by the pattern of the sky 36 of the hologram 32 as perceived by the viewer, but they do not affect the alignment tolerances of the through hole 42 and the laser modified region 38. In this way, the laser modified region 38 and the through hole 42 can be matched to each other in design, regardless of alignment tolerances. In the embodiment of fig. 3, the laser modified regions 38 visually and contextually cooperate with the through holes 42, since both regions do not deviate from depicting the same pattern (sun with light). Other complex adaptations may of course also be produced in the context of the present invention, as described in detail below.

In a novel concept, it is contemplated that a dye or feature substance is disposed around the laser-modified region 38 to alter the visual impression of the laser-modified region 38 as desired. For example, the surrounding areas of the laser modified region 38 of the hologram 32 may be configured with an optically variable layer, such as a color shifting liquid crystal layer. After application to the security paper and demetallization of the regions 38, the through holes 42 become transparent to light, whereas the optically variable effect of the liquid crystal layer is very pronounced when the security paper 40 is placed against a dark background. Here, the desired color impression of the liquid crystal layer can be set by the choice of the liquid crystal material and the thickness of the optically variable layer.

Fig. 4 shows another novel concept of the embodiment in fig. 3, in which the through-holes 42 are formed not only on one side of the security paper 40 but on both sides of the security paper 40 by a register effect. Here, fig. 4(a) shows a cross section of the security paper 40, and fig. 4(b) and 4(c) show holograms or through-hole regions of the top and bottom surfaces of the security paper 40, respectively.

In order to produce a security paper with a register effect on both sides, a laser-changeable marking substance, which can be brought to 10.6 μm CO, is arranged in the region 44 of the security paper 40 around the through-hole to be produced, before the through-hole 42 is cut₂The laser light changes color, e.g., from transparent to red, but is not changed by laser radiation of 1.064 μm or 532 nm.

If CO is now used₂The cutting laser cuts the through-hole 42 in the security paper 40 from the bottom side 46, the threshold energy required for the marking substance to change from transparent to red even exceeds the edge region 48 of the through-hole 42 due to the gaussian beam shape of the laser beam. In this way, a through-hole 42 with a red border 48 is created in the bottom surface of the security paper 40.

To complete the design 50 of the bottom surface 46, the security paper 40 may be CO with low laser energy₂The laser radiation is applied randomly with laser energy only exceeding the energy limit required for color conversion and not exceeding the energy limit required for cutting, so that additional colored regions 52 can be formed on the bottom surface 46. Since the cutting of the through-hole 42, the coloring of the edge area 48 and the coloring of the non-cut area 52 are processed with the same cutting laser beam in the same process or in the same operation, the colored areas 48, 52 and the through-hole 42 are perfectly aligned with each other, as shown in fig. 4 (c). Further details regarding the laser variable marking substances available with the present concept and further variations regarding the coloring of the borders or the surrounding areas of the through holes can be found in the publication WO2009/003587a1, the content of which is incorporated by reference as part of the present description.

After the foil element 30 in fig. 3(a) has been applied to the security paper 40 in fig. 4(a) and the hologram has been demetallised in the laser modified region 38, the top of the security paper 40 forms the visual appearance shown in fig. 4(b), which is identical to that in fig. 3 (c). The design 50 of the base 46 does not change during the demetallization, since the marking substance in the regions 44 does not react to the Nd: YAG laser used for the demetallization or the energy, more precisely the irradiation (energy per unit area), is not sufficient to cause a reaction. The latter are particularly suitable for use when thermally reactive dyes are used.

In summary, the finished security paper shows the visual appearance shown in fig. 4(b) and 4(c), respectively, from above and from below, the through holes 42 being combined into one complete picture on both sides (sun scenery and spoked wheel) by register effect.

In a further described embodiment, the radiation-modified region of the security element may cover the entire area of the through-opening. However, the radiation-modified regions may also be provided only in a subsection of the through-hole, thereby forming a sub-pattern inside the region of the through-hole. To create such radiation modified regions with sub-patterns that are perfectly aligned with the vias, the following steps may be employed.

In the embodiment shown in fig. 5, firstly, the foil element 60 is provided with a security element 62, said security element 62 having a first and a second partial region 64, 66 which interact to a different extent with the electromagnetic radiation used for the modification. To this end, the partial areas 64, 66 may be filled, for example, with a metalized grating pattern whose grating lines are arranged rotated by 90 ° relative to one another, as shown in fig. 5(a) by the different cross-hatching (crosshatching) of the partial areas 64, 66. Here, the shape of the partial areas 64 and 66 forms a desired pattern, for example, a letter string "PL" shown in fig. 5 (a).

Then, the foil element 60 is applied to a security paper 70 having a through hole 72 (see fig. 5(b)), and the foil element 60 is irradiated from the bottom of the security paper 70 through the through hole 72 with linearly polarized laser radiation of Nd: YAG laser.

If the polarization plane of the laser radiation is oriented appropriately, the absorption of the laser radiation by the partial regions 64 is significantly higher than the absorption of the laser radiation by the partial regions 66, so that the energy or power of the laser radiation is sufficient to demetallize the partial regions 64 without demetallization occurring in the less absorbing regions 66. In this way, only the partial regions 64 are selectively demetallized in the region of the through-hole 72.

Since the through-hole 72 acts as a mask during the partial demetallization, the laser-modified regions 74 of the security element 62 formed by the demetallized regions are perfectly aligned with the cut edges of the through-hole 72. The regions 66 which are not demetallized by the laser radiation continue without deviation from the outside of the through-hole 72 to the inside of the region of the through-hole 72, as shown in the top view of fig. 5(c) and the cross-sectional view of fig. 5 (d).

In a preferred embodiment, a different fit of the sub-areas 64, 66 can be obtained by a laterally distinct grating, one sub-area having a higher absorption and another area not demetallized having a lower absorption. This is the same as the embodiment shown in fig. 5. Particularly high absorption contrast can be achieved between grating sub-regions when Surface Plasmons (SPs) are excited in these sub-regions, while the other sub-region does not allow such resonance excitation. Preferably, a linearly polarized laser radiation having a predetermined wavelength and angle of incidence is used as the beam source. SPs can result in complete absorption of incident TM mode polarized light (with the E vector perpendicular to the grating lines). In contrast, for a highly conductive metal grating, the polarized light of the TE mode (E vector parallel to the grating lines) is very difficult to absorb. In this way, with a grating having partial areas of different directions (differing by 90 °), an absorption contrast of more than 10, in the infrared range or even more than 100 can be obtained. The noble metals Au, Ag, Pt and Al, Cr and Ni are particularly suitable for the metallization.

For example, a rectangular reflection grating with a period of 1 μm and a groove width of 0.6 μm shows a pronounced absorption maximum for the metals Au, Al, Ag and Cu, with incident radiation having a wavelength of 1,064nm, an angle of incidence of 1 ° and TM mode polarization as the groove depth, e.g., Ag and Cu can almost achieve 100% absorption maximum at a groove depth of about 110 nm.

Since the position of the SPs in the wavelength spectrum depends not only on the grating period, but also on the grating profile and optical constants, absorption differences can also be obtained in partial regions when these parameters of the grating are varied. In addition, through proper design of the grating surface shape, higher absorption of TE mode polarized light and lower absorption of TM mode polarized light can be realized. Here, the absorption of the TE mode polarized light is based on a resonance effect which is particularly pronounced in deep grating patterns (groove depths greater than one-half period).

The different mating of the partial areas 64, 66 can also be achieved in other ways, for example by enlarging the relief pattern by different surfaces. In this case, it is chosen on the basis of the fact that, when a metal layer is vapor-deposited on relief patterns of different roughness, the thinner the metal layer, the coarser the relief produced. Furthermore, in coarser patterning, incident laser radiation is generally reflected more, giving off more energy to the metal layer, so that, overall, a coarser relief pattern can be demetallized with lower laser energy. The key here is the aspect ratio. The larger the aspect ratio, the better the demetallization effect that can be obtained.

The partial regions 64, 66 can in turn also be developed with a coarse relief pattern (partial region 64) and a fine relief pattern (partial region 66), in order to select only the partial region 64 for demetallization. Details regarding the selective removal of only one of the two or more subareas may be found in the patent publication WO2006/079489a1, the content of which is incorporated by reference as part of the present specification.

The formation of different levels of interfitting sub-regions in the security element may also be based on the use of a metallised relief pattern (embossing pattern) having systematically formed protrusions and depressions. In this regard, fig. 6 shows an embodiment in which a foil element 90 is applied to the security element 80 by means of a hot-melt adhesive 84, the security element 80 having a through-opening 82. The foil element 90 comprises a supporting foil 92, which supporting foil 92 is provided with a UV-cured embossed lacquer layer 94 on one side.

A relief pattern having protrusions 96 and depressions 98 is embossed in the relief paint layer 94. Here, the projections and depressions are relative to the surface of the support foil 92, so that these downwardly directed parts in fig. 6(a) constitute projections, since they are higher than the depressions 98, as seen from the surface of the support foil 92.

In this exemplary embodiment, the embossments 96 also have a micro-relief pattern in the form of a predetermined hologram. The entire relief pattern with elevations 96 and depressions 98 is provided with a metal layer 100, for example an aluminum layer, which metal layer 100 also forms the hologram metal layer for the micro-relief pattern with the elevations 96.

The metallized relief pattern is also continuously coated with a laser beam absorbing and/or laser beam reflecting lacquer 102 which fills the depressions 98 of the relief pattern. In one example, the lacquer 102 may be a UV lacquer having high thermal stability, with an infrared absorber distributed therein, the infrared absorber having an absorption maximum at the near infrared. After this application, the applied lacquer is scraped, ground or rubbed off the surface of the relief pattern, technically unavoidable and often a thin toner film remains on the protrusions 96 of the relief pattern. Overall, this produces a metallized relief pattern with lacquer 102 as shown in fig. 6(a), the lacquer 102 completely filling the depressions 98 of the relief pattern and appearing as a thin tinted film on the protrusions 96.

After the foil element 90 has been applied to the security paper 80, the foil element 90 is irradiated with laser radiation (e.g. Nd: YAG laser radiation) from the bottom surface of the security paper 80 through the through-hole 82, as indicated by the arrow in FIG. 6 (a).

By the laser radiation 86 acting on the lacquered metal layer 100, the raised regions 96 are demetallized, while the metal layer remains in the recessed regions 98. In particular, the laser energy reaching the metal layer 100 in the recesses 98 is not sufficient to cause demetallization due to laser absorbing and/or laser beam reflecting additives in the lacquer 102. In contrast, the metal layer on the protrusions 96, which is only covered by the thin toner film, is demetallized upon receiving a high energy input. Here, the thin toner film may facilitate the demetallization because its absorption properties are generally greater than those of the metal layer 100 itself.

In summary, by laser irradiation, a security document 110 as shown in fig. 6(b) can be produced, wherein the demetallised protrusions 96 in the region above the through-hole 82 constitute laser modified regions 112, which laser modified regions 112 have a modified visual appearance, which visual appearance is perfectly aligned with the cut edge of the through-hole 82. The region formed by the depression 98 continues from outside the through-hole to within the region of the through-hole 82 without deviation. Thus, in principle, the appearance of the security document 110 is the same as that shown in fig. 5 (c). For example, the depressions 98 may form the letter string "PL" to correspond to the partial areas 66 in fig. 5(c), while in the micro-pattern of the projections 96, a background hologram corresponding to the partial areas 64 in fig. 5(c) may be formed.

Further details and variations of the method of forming the metallized relief pattern (with protrusions and depressions) may be found in international application PCT/EP2009/00882, the content of which is incorporated by reference as part of the present specification.

The embodiments in fig. 5 and 6 allow a number of variants and modifications, which can be derived from documents WO2006/079489a1 and PCT/EP2009/00882 mentioned above. For example, unlike fig. 6, the non-demetallized depressions may also have a micro-relief pattern therein, or only the depressions and not the protrusions may be provided with a micro-relief pattern. The pattern in the embossing lacquer is usually recognizable without the metal layer. However, if the lacquer 102 in FIG. 6 has a similar refractive index as the embossed lacquer 94, the pattern may also be developed to be indistinguishable.

In a further variant, there is no pattern in the metal area. In this connection, it is possible, for example, to select the patterns described in the patent document with publication number WO2006/079489 (FIG. 5) such that they are difficult to see with the naked eye, or to provide the elevations and depressions for the demetallization (FIG. 6) without other patterns. In both cases, after demetallisation, it is in fact possible to produce the visual appearance of the security element 120 shown in fig. 7, in which the differently fitted sub-regions 122, 124 outside the through-hole 126 appear the same to the naked eye. The partial areas 122, 124 allow visual differentiation only inside the through hole 126, wherein the first partial area 122 is modified by laser irradiation forming a radiation modified area 128, which radiation modified area 128 has a changed visual appearance. For illustration, as shown in fig. 7, in the area 125 outside the through-hole, some of the divisional areas 122, 124 that cannot be distinguished with the naked eye are drawn with broken lines.

In the embodiment shown in fig. 6, it is also possible to use printing ink as a layer that absorbs laser radiation and prevents demetallization. In the bottom view of the security paper of the invention as shown in fig. 8, a color pattern 130 in the form of a radiation modified region 112 can be seen on the bottom surface, which color pattern 130 is exactly aligned with the demetallized regions and the through-holes 82.

Here, for the layer structure, embodiments may be considered in which the metal layer is located above the foil and the foil is located above the printing ink, or the metal layer is located between the foil and the printing ink, or the metal layer is located above the printing ink and the printing ink is located above the foil. The visual appearance of all three embodiments is the same as that shown in figure 8.

If the laser absorbing lacquer of fig. 6 is chosen to be coloured and a pattern is provided in the lacquer, a two-colour reverse pattern can be produced in register with the hologram or matte pattern. Here, if a variant is chosen in which the lacquer protects the metal layer from the laser radiation, the visual impression shown in fig. 5(c) results when viewed from the top and the visual impression shown in fig. 8 when viewed from the bottom.

Alternatively, a variant can also be chosen in which the demetallised layer is supported by the lacquer 102, as described in detail in application No. PCT/EP 2009/00882. Here, the lacquer used is preferably applied more thinly, so that a transparent appearance is easily provided. If a non-transparent lacquer is used, the through-hole will be rendered non-transparent.

The features described with reference to fig. 5 and 6 may also be combined with each other. Further design elements in contrast to the surrounding area may appear and/or disappear in the through hole.

The invention can be used in embodiments with particular advantage in micro-optical rendering devices, developed in particular as moire magnification devices, micro-optical moire-type magnification devices or mode magnification devices. The basic principle of these depicting devices is explained in the patent document with publication number WO2009/000528a1, the content of which is incorporated in the present description.

In the embodiment shown in fig. 9, the foil element 140 is applied to the security paper 160 by means of a hot melt adhesive 164, the security paper 160 having a through hole 162. The foil element 140 comprises a supporting foil 142, the top surface of which supporting foil 142 is provided with a grid-like arrangement of micro-lenses 144 forming a two-dimensional, preselected symmetrical grating on the surface of the supporting foil. The diameter of the spherical or aspherical microlenses 144 is preferably from 5 μm to 50 μm, particularly preferably from 10 μm to 35 μm.

On the bottom side of the support foil 142 a graphic layer 146 is arranged, which graphic layer 146 comprises a graphic image with micro graphic elements 148, which graphic layer 146 is divided into a plurality of cells. The arrangement of the grating elements likewise forms a two-dimensional preselected symmetrical grating. The grating period and the diameter of the grating elements of the pattern image are of the same order of magnitude as the microlenses 144, preferably 5 μm to 50 μm, particularly preferably 10 μm to 35 μm, so that the micropattern elements 148 are not discernible to the naked eye like the microlenses 144.

In the moire magnification device, the grating of the grating unit is slightly different from the grating of the microlens 144 in terms of symmetry and/or magnitude of grating parameters, and a moire magnification image of the micro pattern element 148 is formed according to the type and magnitude of deviation when viewing the pattern image. More generally, modulo magnification arrangements, in which the graphical image need not be constituted by a raster with an independent pattern that repeats periodically, are used. The basic principle and further details of the die-magnifying device can be found in the above-mentioned publication WO2009/000528a 1.

In the embodiment shown in fig. 9, the graphic layer 146 includes an embossed lacquer layer 150 including protrusions 152 and depressions 154, the embossed lacquer layer 150 first being continuously coated with a metal layer 156, substantially as described in fig. 6. In the embodiment of fig. 9, the micro-graphic elements 148 are precisely formed by the depressions 154 in the layer of relief lacquer 150.

As shown in fig. 6, the metallized relief pattern 150, 156 is coated with a laser beam absorbing lacquer 158 that fills the depressions 154 and forms a thin tinted film over the protrusions 152. The foil element 140 is then applied to the security paper 160, after which the foil element 140 is irradiated from the bottom surface with laser radiation through the through-hole 162. In this way, the bumps 152 in the area above the through-holes 162 are demetallized, while the metal layer 156 is retained in the recesses 154. Outside the through-hole 162, the metal layer is completely unchanged on the protrusion 152 and in the depression 154.

When viewed, in the finished security paper, the moire magnification micro graphical elements 148 (depressions 154) can only be seen inside the through holes 162 with the demetallized protrusions 152 as background, while they are not seen outside the through holes 162, due to the lack of contrast between the metallized depressions 154 and the metallized protrusions 152.

In general, for the embodiment shown in fig. 9, the visual appearance shown in fig. 7 can be produced, however, when the security paper is tilted, the stars 124, which are moire magnification micro-graphic elements 148, are displaced according to the magnification effect selected, for example orthogonally displaced with respect to the direction of tilt. Since the through-hole 162 acts as a mask when the relief 152 is demetallized, in each case a change in appearance from the star 124 to a uniformly present metal layer occurs at the cut edge of the through-hole 162, irrespective of whether the security paper is tilted or not.

The same appearance as in fig. 5(c) with a magnifying effect can also be produced if the relief lacquer layer 150 is additionally provided with a micro-relief pattern on the protrusions. The letter "PL" is transferred due to the magnifying effect, the demetallization layer being accurately present at the boundaries of the via. Inside the through-hole 162 the moire magnification micro-graphic elements (depressions) can be discerned against the background of the demetallized bumps, while outside the through-hole 162 they are also discernable against the background of the raised micro-relief pattern, which forms a background hologram.

The embodiments described in connection with fig. 5 and 6 can also be implemented in the micro-optical rendering device if the laser-absorbing lacquer layer in fig. 9 is selected for coloring. This may also result in a back side with a micro-optical magnification effect if the back side of the supporting foil is laminated with a lens.

The demetallised region may also be arranged beyond the micropattern such that an inverse pattern may be created in the region of the via, the inverse pattern being formed by demetallised regions arranged in the shape of the pattern inside the metal layer. The demetallized areas of the pattern shape may be designed in the form of a geometric pattern or an arabic character string.

Fig. 10 shows another embodiment of a moire magnification device 170, and the structure of a part of the moire magnification device 170 is the same as that of the micro-optical magnification device shown in fig. 9, and elements denoted by the same reference numerals correspond to each other. When the moire magnification device 170 of fig. 10 is viewed, the moire magnification micro-graphic elements 174,176 are visible both within and outside the aperture 162, but have a different color impression from each other.

In this embodiment the graphic image of the magnification means is constituted by a colored graphic layer 172, which graphic layer 172 is provided with micro graphic elements 174, the color of the graphic layer 172 being changed by the laser radiation. To this end, the graphics layer 172 may comprise, for example, laser-variable pigments having different characteristics (in particular their surface color), which are available to the person skilled in the art, which change color under the conditions of laser action, threshold energy and desired laser wavelength.

After the foil element with the graphic layer 172 has been applied to the security paper 160, the micro-graphic elements 174 initially have the same initial color. Due to the laser irradiation from the bottom side of the security paper 160 through the through-opening 162, a perfectly aligned color change is caused in the graphic layer 172 in the region of the through-opening 162, so that the color of the micro-graphic element 176 there changes. When viewing the magnifying device 170, a combination of the moire magnification micro pattern elements 174 having a first color outside the through holes and the moire magnification micro pattern elements 176 having a second color inside the through holes are visible.

The color change may include a change from a transparent graphic layer to a color graphic layer or a decoloration of a color graphic layer, in addition to a change from a first color to a second color. In the second case, a color magnification effect can be produced that is only visible in the through-hole and perfectly aligned with the through-hole, while in the last case, a magnification effect can be produced that is only visible outside the through-hole and ends right at the cut edge of the through-hole.

The use of laser radiation is not essential to the discoloration or bleaching of the lacquer, but can also produce a color change by UV or IR exposure. For lacquers in these variants which cannot be bleached by sunlight, the lacquer of the foil 142 and/or the microlenses 144 is preferably provided with a suitable UV or IR absorber.

Fig. 11 shows another embodiment of the invention, in which the micro-optical rendering device 180 accurately shows the variation of the rendered graphical image at the cut edge of the through-hole 162 of the security paper 160.

Outside said through hole 162, a first graphic image can be seen, comprising a first moire magnification micro graphic element 182 in the form of a string of numbers "50", as shown in top view in fig. 11 (b). The first micropattern element 182 therefore occupies the information of the through-opening 162, which is likewise in the form of the string of numbers "50".

Inside said through hole 162, a second graphic image can be seen, comprising a euro symbolA second moire magnification micropattern element 184 in the form. The first and second micro-graphic elements 182, 184 or the through-hole 162 and the second micro-graphic element 184 then complement each other to form the denomination of the banknote. The variation between the first and second graphic images occurs in perfect registration at the cut edge of the via 162.

In order to produce a perfect registration of the image variations, a foil element 190 is used, as shown in fig. 11(a), wherein the bottom surface of the support foil 196 is provided with a two-layer lacquer system having two superposed lacquer layers 192, 194 of the same refractive index. Here, the first micro-graphic elements 182 appear as a relief pattern in the upper paint layer 192 (viewed from the supporting foil 196 side) and the second micro-graphic elements 184 appear as a relief pattern in the lower paint layer 194 (viewed from the supporting foil 196 side). The supporting foil 196 is provided on both sides with a grid of microlenses 144, which cooperates with the grid of the micropattern elements 182, 184, as described above.

In the region of the through-opening 162, the upper lacquer layer 192 of the lacquer system melts perfectly in register when the foil element 190 is irradiated with laser light from the bottom side of the security paper 160 through the through-opening 162. Therefore, when looking through the microlens 144 around the through-hole 162, only the inside of the through-hole can be seenA second micro-graphic element 184 in the form of a symbol (see fig. 11(b)), which second micro-graphic element 184 is displayed in the lower paint layer 194.

Outside the through-opening 162, two paint layers 192, 194 are superimposed directly on one another. Because they have the same index of refraction, light transmitted through the relief pattern 184 is not affected at the intersection of the paint layers 192, 194, and thus the second micropattern element 184 is not discernable outside the through-hole 162. Only the first micropattern element 182, shown in the form of a string of numbers "50", is identifiable due to the difference in refractive index at the interface of the upper paint layer 192 and the adjacent layer 198 (e.g., a heat seal coat). If the layer 198 is dyed, the first graphical element 182 outside the via 162 is colored, while the second graphical element 184 inside the via 162 is transparent.

Here, the topcoat 192 is designed to be thin enough to ensure that the first and second micropattern elements 182, 184 lie substantially in the focal plane of the microlenses 144 and appear sharp when viewed.

In fig. 11(a), the first micropattern element 182 and the second micropattern element 184 are drawn to overlap for simplicity of illustration, but in practice they are not typically directly superimposed on one another.

In other embodiments of the invention said security element arranged on the foil element is formed based on a combination of micro lenses and concave micro mirrors, thereby forming a micro-optical delineation means visible from both the top and the bottom.

Referring to fig. 12, such a security element 201 applied to a banknote comprises a support 203, the top surface 204 of which 203 is provided with a raised micro-pattern 205 and the bottom surface 207 is provided in two parts with a plurality of concave micro-mirrors 208 and a plurality of micro-lenses 209. The concave micro-mirrors 208 and the micro-lenses 209 are located in a plane perpendicular to the plane shown in fig. 12 and in a grid having a fixed geometry, such as a hexagonal grid, and are arranged regionally in a viewing element pattern.

Here, the support 203 comprises a PET foil 210 on which a first layer 211 is provided, the first layer 211 being composed of a radiation-curable lacquer and having a micro-pattern 205. A second layer 212 of radiation-cured lacquer is arranged on the bottom side of the PET foil 210, the second layer 212 having the inverse shape of the concave micro-mirrors 208 and the shape of the micro-lenses 209 embossed therein.

The micropatterns 205 forming micropattern objects or micropatterns M1 likewise lie in a plane perpendicular to the plane shown in fig. 12 and in a grid having a fixed geometry, here again by way of example a hexagonal grid, are arranged planarly in a microstructure pattern which is matched to the viewing element pattern in such a way that, when the security element 201 is viewed from the top (direction of arrow P1), the micropatterns 205 form, together with the concave micromirrors 208, a die or moire magnification device, as described in detail in the above-mentioned patent documents with publication nos. WO2009/000528a1 and WO2006/087138a 1. Here, the micro pattern object M1 of the present invention is the same as the graphic image taught in patent document WO2009/000528a 1. To the viewer, toward the viewing direction of the top (the direction of the arrow P1), the micro-pattern object M1 is recognizable, enlarged as a security feature (equivalent to the target image in WO2009/000528a 1).

For producing the concave micro-mirrors 208, the side of the second layer 212 facing away from the PET foil 210 is provided with a light-reflecting coating 213, in particular a metal layer, in the region a, so that the concave micro-mirrors 208 are formed as back reflectors. In this exemplary embodiment, the inner side of the light reflective coating 213 of each concave micro-mirror 208 or the relief shape of the concave micro-mirror 208 is in the shape of a spherical cap with a radius of curvature of 38 μm and a height of about 3 μm. The layer thicknesses of the second layer 212, the PET foil 210 and the first layer 211 are chosen such that the micro-pattern 205 is spaced only 19 μm from the concave micro-mirrors 208 and thus lies in the focal plane of the concave micro-mirrors 208, so that a predetermined magnified image of the micro-pattern 205 is effected, resulting in a security feature.

In the region B of the security element 201, the metal layer 213 is removed by demetallisation so that the shape of the relief forms the microlenses 209, rather than the concave micro-mirrors. Here, the radius of curvature of the convex surface 214 of the microlens 209 is the same as the radius of curvature of the concave micro-mirror 208, in this exemplary embodiment 38 μm, which results in a focal length of the microlens 209 of about 115 μm. The plane E of the focal length 0 of the microlenses 209 is then located outside the security element 201, so that the micropattern 205 is not visible in the region B when viewed from the bottom surface 207 of the security element 201 (direction of arrow P2).

The micro-lenses 209 are not intended to depict the micro-pattern 205 but to authenticate another banknote or to self-authenticate a banknote having the security element 201. For self-authentication, a further micropattern object (not shown) is provided in a plane E in front of the top surface 204 of the support 203 of the security element 201 by bending, creasing or folding the banknote such that, from a viewing direction towards the bottom surface 207, the further micropattern object is magnified by the microlenses 209 and imaged, the further micropattern object being contained in the banknote at a location laterally spaced from the security element 201.

For the authentication of a further banknote, the image of a further micropattern of which is arranged in the plane E in front of the top face 204 of the security element 201, an enlarged image is formed through the bottom face 207 by means of the microlenses 209, so that the authentication of the further banknote can be effected.

According to the invention, the demetallization of the metal layer 213 takes place after the application of the security element 201 to a security paper having through holes and the irradiation of the metal layer 213 with radiation from the bottom surface 207 of the security element 201 through the through holes of the security paper, as described above. In this way, it is ensured that the transitions of the micro mirrors 208 to the micro lenses 209 (the boundaries of regions a and B in fig. 12) are perfectly aligned at the cut edges of the through-holes.

The concave micro-mirrors 208 and the micro-lenses 209 may also be in different planes, as shown in the cross-sectional view of fig. 13. The structure of the layer 210 and 212 is the same as that shown in fig. 12, and the mirror side of the concave micro-mirror 208 is provided with a continuous metal layer 213, which is drawn with a solid line (area a) in fig. 13. In the region B, the metal layer 213 is partially removed by irradiation with radiation to produce a semi-transparent concave micro-mirror 208', which is drawn with a dotted line in fig. 13. Here, the metal layer is in particular superimposed with a sub-pattern, for example a dot or wire grid, and is completely removed in partial areas corresponding to the sub-pattern, so that a translucent metal layer is substantially produced.

A second PET foil 222 is fixed to the layer 212 by means of a laminating adhesive 221, which second PET foil 222 is provided with a UV lacquer layer 223, in which UV lacquer layer 223 the convex surfaces 214 of the microlenses 209 are embossed. The convex surface 214 is in the shape of a spherical cap having a radius of curvature of 18 μm. Since the radius of curvature of the convex surface 214 of the microlens 209 is 18 μm, the focal length of the microlens 209 is 54 μm, which for a chosen layer thickness is exactly equal to the spacing between the highest point of the convex surface 214 and the micropattern 205.

Also in this embodiment the demetallisation of the metal layer 213 is performed after applying the security element 201 to a security paper having through holes and irradiating the metal layer 213 with radiation from the bottom surface of the security element 201 through the through holes of the security paper and the second PET foil 222. In this way, a transition from the fully metalized micro-mirror 208 to the semi-transparent concave micro-mirror 208' is created that is fully aligned with the cut edge of the via.

Outside the via (region a), the micro-pattern 205 is visible to the viewer from above (viewing direction P1) through the reflective fully metallized micro-mirror 208. Inside the through-hole (region B), the micro-pattern 205 can be seen from both the top and bottom, specifically, once by reflection from the translucent concave micro-mirror 208 '(viewing direction P1), once through the micro-lens 209 and the translucent concave micro-mirror 208' (viewing direction P2).

Further details and advantages of the combination of micro-lenses and concave micro-mirrors may be found in the german patent application DE102009022612.5, the content of which is incorporated by reference as part of the present description.

If the foil element is applied to the security paper by means of hot melt adhesive or other adhesive, the hot melt adhesive 84 may protrude slightly into the area of the through hole 82 due to alignment tolerances, as shown in fig. 6. This will make the appearance of the edge area of the through hole somewhat blurred. Thus, in all embodiments, the adhesive may be laser ablatable so that it may be applied continuously, and modified by laser removal in the region of the through-hole 82. The adhesive layer is likewise in perfect alignment with the cut edges of the through-holes, as shown by hot melt adhesive layer 198 in fig. 11 (a). For this purpose, the adhesive is preferably provided with a suitable absorber for the laser radiation.

As described and shown in the exemplary embodiments, a multi-layer system can also be used instead of simple metallization. If the laser parameters are appropriately selected, the layers can be removed from such a layer system in the region of the through-hole. For example, in a thin film element having a color shift effect, the thin film element generally includes a reflective layer, a dielectric spacer layer, and an absorbing layer, and only the reflective layer or only the absorbing layer can be removed by laser irradiation.

Of course, the above-described variants can be used not only for security papers, but also for other data carriers with through-holes, such as plastic banknotes or foil composite banknotes. Here, only one foil needs to be processed by the laser, and the second foil must then be transparent to the laser or not yet be coated in the laser processing step.

List of labels

10 banknote 12 banknote paper 14 through hole 16 bottom surface 18 top surface 20 foil strip 22 hologram 24 laser modified area 30 foil strip 32 true color hologram 34 mountain 36 sky 38 laser modified area 40 security paper 42 through hole 44 surrounding area 46 bottom surface 48 edge area 50 design 52 color area 60 foil element 62 security element 64, 66 subsection area 70 security paper 72 through hole 74 laser modified area 80 security paper 82 through hole 90 foil element 92 support foil 94 relief lacquer layer 96 raised 98 depressed 100 metal layer 102 laser beam absorbing lacquer 110 security document 112 laser modified area 120 security element 122, 124 subsection area 125 outside area of through hole 126 radiation modified area 128 through hole 130 color pattern 140 foil element 142 support foil 144 microlens 146 pattern layer 148 microlens pattern element 150 relief lacquer layer 152 raised 154 depressed 156 metal layer 158 laser beam absorbing lacquer pattern Lacquer 160 security paper 162 linear polarizing layer 164 hot melt adhesive 170 moire magnification device 172 pattern layer 174, 176 micro graphic element 180 micro optical delineation device 182, 184 micro graphic element 190 foil element 192, 194 lacquer layer 196 support foil 198 abutting layer 201 security element 203 top surface 205 micro pattern 207 bottom surface 208 micro mirror 208' translucent concave micro mirror 209 PET foil 211 radiation curing lacquer 212 radiation curing lacquer 213 metal layer 214 convex surface 221 of the micro lens laminating adhesive 222PET foil 223UV lacquer layer.

Claims (33)

1. A data carrier comprising:

-a window extending from the bottom of the data carrier to the top of the data carrier;

-a foil element with a security element covering the window on top of the data carrier, the security element being partly on the window and partly close to the window;

it is characterized in that the preparation method is characterized in that,

-the portion of the security element above the window has a radiation modified region which is aligned with the window and in which the visual appearance of the security element is altered under the action of electromagnetic radiation.

2. A data carrier as claimed in claim 1, characterized in that the security element has a metal layer, the metal layer in the radiation-modifying region being demetallized.

3. A data carrier as claimed in claim 2, characterized in that the security element comprises a metallized diffraction pattern, a metallized blazed diffraction pattern, a metallized matte pattern or a thin-film element with a color-shifting effect.

4. A data carrier as claimed in claim 1, characterized in that the security element has a first and a second subregion which interact differentially with electromagnetic radiation, the first and second subregion being situated partly above the window and partly close to the window.

5. A data carrier as claimed in claim 4, characterized in that the radiation modification region comprises only a first partial region and not a second partial region, so that the second partial region exhibits the same visual appearance above and close to the window.

6. A data carrier as claimed in claim 4, characterized in that at least one of the two partial areas has an interference pattern.

7. A data carrier as claimed in claim 6, characterized in that at least one of the two partial areas has a relief pattern in the form of a grating pattern, which grating pattern is determined by a grating constant and the direction of the grating lines.

8. A data carrier as claimed in claim 4, characterized in that at least one of the two partial areas has a surface-enlarging relief pattern.

9. A data carrier as claimed in claim 4, characterized in that the first and second subregion are formed by elevations and depressions of a relief pattern.

10. A data carrier as claimed in claim 9, characterized in that the recesses are filled with a radiation-reflecting and/or radiation-absorbing cover layer.

11. A data carrier as claimed in claim 1, characterized in that the security element comprises a micropattern with a line width of 1 μm to 10 μm, the visual appearance of which micropattern is altered in the radiation-modifiable region.

12. A data carrier as claimed in claim 11, characterized in that the micropattern forms a graphic image at least in the radiation-modified regions, the graphic image being subdivided into a plurality of cells, in each of which a specific target-image imaging region is provided, the imaging region having a lateral dimension of 5 μm to 50 μm.

13. A data carrier as claimed in claim 12, characterized in that a viewing grid consisting of a plurality of viewing grid elements having a lateral dimension of 5 μm to 50 μm is used for reproducing a specific target image when viewing the graphic image by means of the viewing grid.

14. A data carrier as claimed in claim 11, characterized in that the colour of the micropattern in the radiation-modifying region is changed.

15. A data carrier as claimed in claim 11, characterized in that the micropattern inside and outside the radiation-modified region each describes a different motif.

16. A data carrier as claimed in claim 15, characterized in that the graphic is a pattern, a character or a code.

17. The data carrier according to claim 11, wherein the micro-pattern is provided in a two-layer paint system comprising two overlapping paint layers having substantially the same refractive index, a second graphical image being embossed in a lower paint layer, a first graphical image being embossed in an upper paint layer provided on the lower paint layer, the upper paint layer in the radiation-modified region being removed such that the second graphical image of the lower paint layer in the radiation-modified region and the first graphical image of the upper paint layer outside the radiation-modified region are visually distinguishable.

18. A data carrier as claimed in claim 1,

-the security element comprises a plurality of retroreflective first micro-graphic elements arranged regionally in a viewing element pattern and a permeable second micro-graphic element arranged regionally in the viewing element pattern,

-said first micropattern element is located inside said radiation modified region and said second micropattern element is located outside said radiation modified region,

-said security element further comprises a micropattern object comprising a plurality of micropatterns arranged in a micropattern pattern that cooperates with said viewing element pattern such that said micropattern object is magnified imaged in front of said top by said first micropattern element, and

-an object plane located outside the security element, the object plane being assigned to the second micropattern element such that the micropattern of the micropattern object is unrecognizable when viewed from the bottom using the second micropattern element, but for verification a further micropattern object having a plurality of micropatterns may be located within the object plane area such that the further micropattern object is imaged magnified in front of the bottom by means of the second micropattern element.

19. A data carrier as claimed in claim 18, characterized in that the first micropattern element is a concave micro-mirror and/or the second micropattern element is a micro-lens.

20. A data carrier as claimed in claim 1, characterized in that the window is in the form of a pattern, a character or a code.

21. A data carrier as claimed in claim 1, characterized in that the window is constituted by a through-hole which extends from the bottom of the data carrier to the top of the data carrier.

22. A data carrier as claimed in claim 1, characterized in that the window is formed by a transparent area of the data carrier, which transparent area extends from the bottom of the data carrier to the top of the data carrier.

23. A data carrier as claimed in claim 1, characterized in that the data carrier is multilayered and the window comprises a through-hole in at least one data carrier layer.

24. A data carrier as claimed in claim 21 or 23, characterized in that the through-openings are formed by a wire grid consisting of a plurality of parallel cutting lines.

25. A data carrier as claimed in claim 1, characterized in that the radiation-modified regions are in the form of patterns, characters or codes.

26. A data carrier as claimed in claim 1, characterized in that the foil element is applied to the top surface of the data carrier by means of a laser-ablatable adhesive layer and the laser-meltable adhesive is removed in the region of the window.

27. A method of manufacturing a data carrier, the method comprising:

a) providing a data carrier substrate and a foil element with a security element, the data carrier comprising a window extending from a bottom surface to a top surface of the data carrier substrate;

b) covering the window with the foil element on the top surface of the data carrier substrate in such a way that the security element is partly located on the window and partly close to the window; and

c) irradiating the security element with electromagnetic radiation through the window from the bottom surface of the data carrier substrate to change the visual appearance of the security element in a radiation modified region, the radiation modified region being located on the window.

28. A method according to claim 27, characterised in that in step c) the security element is irradiated with laser radiation.

29. The method of claim 28, wherein the laser radiation is ultraviolet radiation, visible radiation, or near infrared radiation having a wavelength of up to 1.5 μ ι η.

30. A method as claimed in claim 27, characterized in that in step b) the foil element is applied to the top side of the data carrier by means of a laser-ablatable adhesive, and in step c) the laser-ablatable adhesive in the window area is removed.

31. Method as claimed in claim 27, characterized in that the window is formed by a through-hole or the data carrier is multilayered and the window comprises a through-hole in at least one data carrier layer, which through-hole is formed in the data carrier substrate or in the data carrier layer containing the through-hole in step a) by stamping or laser cutting with a cutting laser.

32. The method of claim 31, wherein the laser is a laser having a wavelength of 10.6 μm.

33. The method of claim 30,

-the data carrier substrate or the data carrier layer is provided with a laser variable marking substance at least around the through-hole to be produced;

-said through-holes are formed in said data carrier substrate or said data carrier layer under the influence of laser radiation;

-said laser variable marking substance around said through hole is altered under the influence of said laser radiation.