WO2016177447A1

WO2016177447A1 - Security feature and method for producing the same

Info

Publication number: WO2016177447A1
Application number: PCT/EP2016/000595
Authority: WO
Inventors: Veronika RACK
Original assignee: Giesecke & Devrient Gmbh
Priority date: 2015-05-04
Filing date: 2016-04-11
Publication date: 2016-11-10
Also published as: PL3291999T3; EP3291999A1; DE102015005672A1; EP3291999B1; ES2730450T3

Abstract

The invention relates to a method for producing a security feature for a security element, a security paper or a data carrier, which comprises a substrate (18), wherein the substrate (18) is provided with a marking substance (19), which can be modified in its colour by laser radiation (44), holes (16) that have a rim and are of a certain hole cross section (C) are introduced into the substrate (18) by the effect of laser radiation (44) that is distributed in intensity in the beam cross section (30), wherein at the same time, on account of the intensity distribution (30) over the beam cross section, the marking substance (19) is modified by the laser radiation (44) in a zone (20) that surrounds the rim and is of a certain zone width (A) such that the ring is coloured, wherein the holes (16) perforate an area (14) and all neighbouring holes within the area (14) are arranged at a centre-to-centre hole spacing (D) from one another that is no greater than 2.5 times the sum of the maximum hole diameter and twice the zone width (A).

Description

S y o u rc h o u rk a nd e u nd it s t o ve r a tio n s

The invention relates to a method for producing a security feature for a security element, a security paper or a data carrier, which has a carrier, wherein the carrier is modifiable by laser radiation in terms of its color, by the action of laser beam in the beam cross-section intensity-distributed laser holes of certain hole diameter in the Carrier are introduced, which have an edge, wherein at the same time due to the intensity distribution over the beam cross section in a zone surrounding the edge of certain zone width of the carrier is modified by the laser radiation, so that the edge is colored. The invention further relates to a security feature for a security element, a security paper or a data carrier, which has a carrier which is modifiable in terms of its color, in the carrier holes of certain hole diameter are introduced, which have an edge, and in one the edge surrounding zone of certain zone width of the carrier is modified so that the edge is colored, and a security element, a security paper and a value document or a data carrier with such a security feature.

Identity cards, such as credit cards or identity cards, are often laser engraved with an individual label. The production of continuous openings in value documents, eg banknote papers, by laser cutting has also been known for some time. Thus, for example, DE 4334848 C1 describes a security with a window-like opening closed by a transparent covering film, which can be produced by a laser cutting process. WO 2009/003587 AI describes a manufacturing method and a corresponding security feature of the type mentioned, which is produced by a laser cutting process. The support of the security feature is provided with a marker that changes its color by the action of laser beams. For the production of the hole or holes, a cutting laser beam is used whose intensity is not uniformly distributed in the radiation cross section, for example Gaussian. Such radiation is referred to herein as laser radiation which is intensity-distributed across the beam cross-section, the radiation intensity decreasing towards the edge of the laser beam. This drop in intensity produces an edge at which the support is no longer cut, but a modification of the marking substance takes place with regard to its color effect. In this way, the edge region of the hole produced by laser radiation appears colored.

A colored border of holes is also known from WO 2009/003588 AI, but here several laser beams of different intensity are needed to achieve a particularly large and therefore well-recognizable color effect.

Laser radiation-sensitive markers are known, for example, from the following publications: EP 1657072 Bl, EP 000002332012 Bl, US 7270919, US 7485403, US 7998900, US 8021820, US 8048608, US 8048605, US 8083973, US 8101544, US 8101545, US 8105506, US 8173253, US 8178277, US 8278243, US 8278244 and US 842028.

The invention is therefore based on the object, a security element, security paper and data carriers of the type mentioned above To further improve the imitation security and to simplify the manufacturability.

This object is achieved by a method for producing a security feature for a security element, a security paper or a data carrier, wherein a carrier is provided, which is modifiable by laser radiation in terms of its color, by the action of laser beam in the beam cross-section intensity laser holes of certain hole diameter in the carrier are introduced, which have an edge, wherein at the same time due to the intensity distribution over the beam cross section in a zone surrounding the edge certain zone width of the carrier is modified by the laser radiation, so that the edge is colored, the holes are arranged covering a surface and within the area, adjacent holes are arranged at a hole pitch centered on the hole center which is not larger than 2.5 times the sum of the maximum hole diameter and the double zone width.

The object is further achieved by a method for producing a security feature for a security element, a security paper or a data carrier, wherein a carrier is provided, which is modifiable by laser radiation in terms of its color, by the action of laser beam in the beam cross-section intensity laser holes of certain hole diameter in the Carrier are introduced, which have an edge, wherein at the same time due to the intensity distribution over the beam cross section in a zone surrounding the edge certain zone width of the carrier is modified by the laser radiation, so that the edge is colored, the holes are arranged covering a surface and within the area the holes make up at least 50% of the size of the area.

The object is likewise achieved by a security feature for a security element, a security paper or a data carrier which has a carrier, wherein the carrier is modifiable in terms of its color by laser radiation, in the carrier holes of a certain hole diameter are introduced, which have an edge , and in a zone of certain zone width surrounding the edge, the carrier is modified so that the edge is colored, the holes covering one surface and within the surface all adjacent holes are located in a hole center spaced hole distance from each other greater than 2.5 times the sum of maximum hole diameter and double zone width.

The object is also achieved by a security feature for a security element, a security paper or a data carrier having a carrier, wherein the carrier is modifiable in terms of its color by laser radiation, in the carrier holes of certain hole diameter are introduced, which have an edge, and in a zone of certain zone width surrounding the edge, the carrier is modified such that the edge is colored, the holes covering one surface and within the surface the holes make up at least 50% of the size of the surface.

The principle of the invention thus provides to perforate the surface, wherein said geometric specifications are met. The perforation makes it possible to structure the surface with regard to an outer or inner edge. The outer boundary of the surface can then be a mo- code. Further, recesses can be provided within the surface, in which no perforations are provided, so that an inner boundary is given, which can contribute to the motif. In the mathematical sense, the perforated surface is thus at least path-coherent, without inner boundary also simply connected.

Of course, a plurality of surfaces can be provided which, among other things, can also be identical, for example in the form of a plurality of lines, each forming a surface, which lie next to one another.

The term "adjacent holes" refers to the shape of the surface, and if the surface has an inner boundary, ie, at least one recess, and an outer boundary, as indicated by the example, the holes at the boundary are those within the surface adjacent to lying holes, of course not to the area outside the boundary, where the surface ends inside or outside an area outside the boundary of the area can preferably be provided with a coloration that is similar to the hole edges. that the boundary of the surface is at least partially not visible, in view when the holes are visible, but clearly stands out.

The holes can be arranged in particular in a dot matrix. Various raster structures are possible, such as hexagonal rasters, rectangular rasters etc. For surfaces with an inner boundary, it is preferable not to form holes at individual points of the dot matrix, and thus to create the recess and the inner boundary. These locations may be colored in a further preferred embodiment in the color of the hole edges, eg by the hole pattern correspondingly arranged points, and most preferably a motif, encode sign or symbol that is not or poor in plan view, but clearly visible in the clear.

The invention uses a special arrangement of the holes in the perforated surface in order to reinforce and bring to the foreground the color effect described in WO 2009/003587 A1. The term "color" is not limited to a colorful impression but may also include black The perforation of the surface according to the invention produces a colored impression without a viewer having to search for a colored hole edge first, which is the case with a single hole or a single hole In the transmitted light, on the other hand, a transparent impression is imparted.With the arrangement of the holes such that adjacent holes have a hole spacing that does not exceed a certain level, the colored impression is particularly noticeable in a plan view of the surface. Thus, according to the invention, several holes interact with regard to the colored impression.

The color effect is achieved in some embodiments by using a support that is directly modifiable with the laser radiation. In other embodiments, the support is previously provided with a suitable marker, e.g. coated, which is modifiable.

The color effect becomes stronger, the smaller the distance between the edges of the holes, ie the denser the perforation of the surface. By reference the hole spacing to the hole center, ie the hole spacing as distance between the hole centers of adjacent holes, achieves the feature that the hole spacing related to the hole center is not larger than 2.5 times the sum of hole diameter and double zone width, that the color-changed zones have a comparatively large proportion of the perforated area. This ensures a particularly good color impression. It increases naturally, the higher the proportion of the color-coded zones on the remaining support surface. Therefore, it is alternatively provided that this proportion is at least 50%, preferably even 75% or 90%. Ideally, there is a minimum gap between adjacent holes that is twice the zone width. In the area of this minimum gap, color-coded zones then encounter each other directly. Of course, due to the circular geometry of the holes created by the laser beam, there are areas between adjacent holes where the minimum gap is not present. The minimum gap exists on the connecting line between the hole centers.

The perforated surface according to the invention appears colored in plan view due to the color effect, e.g. by the marker modified in the zones around the holes. At the same time, there is also a motive in transmitted light due to the perforation of the surface and the thus changed translucency. These two motifs are in perfect register with each other, since they were created by one and the same process, namely the perforation of the surface.

The perforated surface is larger in the x and y direction than a hole. It is therefore a two-dimensional area in which holes are juxtaposed in both coordinate directions. The provision of a marker, however, is not relevant to the passport of these two motifs. In principle, it is possible to provide the marking substance over the entire area in a much larger area than the perforated area occupies. In one development, the application or provision of the marking substance and the structure of the perforated surface are combined in such a way that no marking substance is present in individual parts of the surface. In these parts, the holes then have no colored border. In the remaining parts, however, the marker is present and the edges of the holes are colored. This gives another appearance of the security feature that is difficult to imitate. If the marking dye is only provided or printed in certain areas, the colored structure of the motif can only be seen in the reflected light and not in others. This encourages viewing in transmitted light.

By varying the hole spacing, the surface can convey a certain design impression. It is therefore preferred in a development that the surface has a first and at least one second pattern, which differ with respect to the grid structure in which the holes are arranged, and / or the hole diameter and / or the hole spacing.

The laser-radiation-modifiable carrier or its marking substance is modified by the laser beam when the holes are introduced into the carrier. In this case, use is made of the fact that the laser beam energy in an outer region of the beam cross-section is sufficient to modify the marking substance in the zone around the edge of the holes. In this way, a perfect registration of openings and laser-radiation-modified zone is automatically guaranteed. If you want to provide the carrier with the marker, it is coated in an advantageous variant of the invention on its surface with the marker, for example by a printing process. According to another likewise advantageous variant of the invention, the marking substance is introduced into the volume of the carrier. Depending on the carrier material, different methods are available.

If the carrier is formed from paper, the marker can advantageously be mixed with the sheet formation of the paper pulp. A further advantageous possibility is to introduce the marker into the volume of the paper substrate in a dipping bath, or to coat the paper substrate, e.g. in a size press, to impregnate with the marker. Of course, a carrier can also be laser radiation-marked without additional marking substance. A blackening by a thermal effect is just one example of this. If the carrier is formed from a plastic film, e.g. the film can be formed thermoreactive or the marking substance can already be introduced into the volume of the film during the production of the film or subsequently by an impregnation step.

As a marker material come into question with advantage whose visible color is changed by the action of the laser radiation. For example, thermoreactive color pigments, such as ultramarine blue, can be used for this purpose. Advantageously, it is also possible to use marking substances whose infrared-absorbing properties or their magnetic, electrical or luminescent properties are changed by the action of the laser radiation. Security features with such laser-radiation-modified hole edges can be used in particular for the Schinelle authenticity test be used. It is also possible to use a combination of different marking substances, for example in order to enable both a visual and a machine authenticity check of the security feature. If several markers are used, they can be placed next to each other or in different layers one above the other. Alternatively, in one embodiment of the invention, the modification of the carrier / marker may be erosion or destruction. The marker is preferably a metallic coating in this case.

In an advantageous procedure, holes are produced with an oblique cutting edge by the laser cut in the carrier. An oblique cutting edge can be ensured, for example, by guiding the laser beam at a predetermined angle to the surface normal of the carrier when producing the openings. Depending on the selected cutting angle, the size of the edge zone can be set, as will be explained in more detail below. According to an advantageous variant of the invention, laser-radiation-modifiable effect pigments are used as the laser-radiation-modifiable marker. Such effect pigments are available to the person skilled in the art with different properties, in particular with respect to their body color, the color change under laser radiation, the threshold energy and the required laser radiation wavelength. Also, effect pigments which change not only their visible color under laser radiation but their infrared-absorbing, magnetic, electrical or luminescent properties are known to the person skilled in the art. The modification of the effect pigments can be performed with laser radiation in the ultraviolet, visible baren or infrared spectral range, for example, with a C0 ₂ laser wavelength of 10600 nm done.

In another likewise advantageous variant of the invention, a pigment-free laser-radiation-modifiable marker is used. Pigment-free marking substances can also be applied to the carrier or introduced into the carrier volume, for example as intaglio or printing ink. With pigment-free marking materials, a coating of high transparency can be produced, into which a permanent and high-contrast marking can be introduced by laser action at high speed. Pigment-free marking substances can be modified by laser radiation in the ultraviolet, visible or infrared spectral range, for example with the 10600 nm radiation of a C0 ₂ laser. Concrete, non-limiting examples of pigment-free, laser-modifiable marking substances are given in the publications WO 02/101462 A1, US Pat. No. 4,344,885 and EP 0290750 B1, the disclosure of which is incorporated in the present specification to this extent.

The invention also encompasses a security element for security papers, documents of value and the like with a security feature produced according to the method described, wherein the security element has a carrier into which a surface is perforated by the action of laser radiation and which is laser-radiation-modifiable. Such a security element can be designed, for example, in the form of a security thread, a label, a transfer element or a covering film for a window area or a hole in a value document, such as a banknote. In addition, the invention also includes a security paper for the production of documents of value or the like with a security feature produced by the described method, wherein the security paper has a carrier which has a surface which is perforated by the action of laser radiation and which is laser radiation modifiable. Instead of introducing the holes directly into the security paper, this can also be provided with a security element of the type described above. The invention further includes a data carrier with a security feature produced according to the described method, in particular a value document such as a banknote, identity card or the like, the data carrier having a carrier.

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

1 shows a schematic representation of a banknote with a security feature,

FIG. 2 is a detail view of the security feature of FIG. 1, FIG. 3 (a) - (c) the explanation of the production of the security feature, wherein

Fig. 3 (a) shows a schematic diagram of a spatial energy distribution of a laser beam, Fig. 3 (b) shows a spatial distribution of the heat energy generated during cutting, and Fig. 3 (c) details the Dimensions of holes created by the laser beam,

4 is a detail view of the security feature,

5 (a) - (c) are cross-sectional views of a hole of the security feature, FIG. 5 (a) showing the situation before irradiation of the laser radiation, and FIGS. 5 (b) and (c) showing two holes having different wide marginal effects. and

FIGS. 6-9 are plan views of a security feature according to further embodiments.

The invention will be explained using the example of a banknote. Fig. 1 shows a schematic table representation of a banknote 10 with a security feature 12. Fig. 2 in detail the security feature 12 of Fig. 1, which is provided with a plurality of laser holes with a border effect.

FIG. 2 shows in greater detail the security feature 12, which is shown only schematically in FIG. 1. It comprises a surface 14 which is perforated by the introduction of a plurality of holes 16 in accordance with a dot matrix R. The surface 14 is in the embodiment of Fig. 2 in several parts, so that the outline of an elephant and an elephant baby in front of a semi-circular background area results. The arrangement of the holes 16 in the paper 18 covers the surface 14. Each hole 16 is generated by a laser beam. The laser radiation can be pulsed or continuously irradiated. Before the introduction of the holes 16, the paper 18 was provided at least in the region of the surface 14 with a marking substance which is modifiable by the action of laser radiation with respect to a color effect. For example, the marker substance has effect pigments which, when suitably irradiated, change from a transparent, non-colored state to a red state. Each hole 16 has an edge on which lies a zone in which the marker has been modified. This was done by the action of the laser radiation, ie the introduction of a hole and the modification of the marker at the edge happens for each hole 16 simultaneously.

The principle of simultaneous creation of the holes 16 and their edge configuration is illustrated in Fig. 3 (a). FIG. 3 (a) shows by way of example a substantially Gaussian spatial intensity distribution 30 of a laser beam. The fluence therefore decreases from the center to the edge.

In an inner region, a cutting region 32, the laser beam intensity exceeds the minimum energy El required to cut the paper 18. E2 designates in FIG. 3 (a) a reaction energy of the effect pigments of the marker substance, above which the said color change takes place. As can be seen directly from the figure, in an outer region of the laser beam profile, a marking region 34, the fluence between the reaction energy E2 required for the color change and the minimum energy E1 required for cutting is present, so that in this region 34 a color change of the effect pigments is induced, but the paper 18 is not cut.

The paper 18 is therefore laser-cut by the laser beam in a zone at the edge of each hole 16 in perfect registration with the hole 16. colored. The width of the colored zone at the edge corresponds to the width of the marking region 34 and depends on the intensity distribution 30 over the beam cross section, in this case the reaction energy of the effect pigments used and the material properties of the paper 18.

Outside the cutting region 32 and the marking region 34, the laser beam intensity is below the reaction energy of the effect pigments, so that the paper 18 is not changed in color there. The laser-radiation-modifiable marker 19 may be applied to the paper 18, for example printed (see Fig. 3 (c)), or may be incorporated into the volume. This can already be done in papermaking by admixing the effect pigments to the paper pulp during sheet formation or else subsequently in a dip bath or by impregnation, e.g. in a size press.

As effect pigments, which change their visible color by the action of the laser radiation, for example, thermoreactive color pigments, such as ultramarine blue, come into question.

It goes without saying that it is also possible to use two or more effect pigments with different threshold energies or a combination of visually and mechanically detectable effect pigments in order to produce a number of passaged edge effects.

Instead of the effect pigments described by way of example, it is also possible to use a pigment-free laser-radiation-modifiable marker. Such markers can also be printed on the paper 18, for example as intaglio or printing ink, or in its volume. be introduced. Non-pigmented, laser-radiation-modifiable coatings can have a very high transparency in the unlabeled state. By the action of laser radiation, for example a C0 ₂ laser at 10600 nm, can be produced at high speed permanent and high-contrast markers, such as a black lettering in the coating.

In addition to the modification of the marking substance 19 by the laser radiation itself, a modification of the paper 18 itself comes into question.

It is also possible that the heat generated during laser cutting causes the modification. In this way, the modified edge region of the opening can optionally even be greater than the beam extent, as illustrated in FIG. 3 (b).

Fig. 3 (b) schematically shows the spatial distribution 30 'of heat energy generated when cutting an aperture with the laser beam of Fig. 3 (a). As can be seen directly from a comparison of FIGS. 3 (a) and (b), the heated area optionally extends beyond the beam diameter due to the heat conduction.

As already described in FIG. 3 (a), the paper 18 is cut in the cutting region 32, since there the laser energy E required for cutting

Threshold energy exceeds El. If the paper 18 or the marking substance 19 now reacts at least also to the thermal energy generated during cutting, then, given the ratios assumed for FIG. 3 (b), a marking region 34 'whose extension is readily greater than the cross section of the laser beam results can. With E2 'is the necessary here Called reaction energy, beyond which the desired color change occurs,

It is optionally also possible that the marker 19 is removed or destroyed immediately adjacent to the cutting edge, and is modified only from a certain small distance from the cutting edge.

Fig. 3 (c) shows the effect of the laser beam having the intensity distribution 30 on the paper 18. In this embodiment, the paper 18 is coated with the marker 19. A laser beam 44 intersects a hole 16 having a hole diameter C, wherein the hole in cross-section, as shown in Fig. 3 (d), for example, is tapered. As a hole diameter in Fig. 3 (d) of the minimum hole diameter C is entered, which results at the exit side of the laser beam 44 from the paper 18. On the inlet side, one obtains a maximum hole diameter, which is greater by a two-fold removal width B than the minimum hole diameter C. The sum of C and 2B results in the maximum hole diameter, which should also be denoted below by (C + 2B). Due to the non-uniform, falling to the edge of the beam cross-section intensity distribution 30 creates a zone 20 in which the fluence of the laser beam 44 above the above-mentioned reaction energy E2 or E2 ', but below the minimum energy required to perforate the paper 18. In this area, the marker 19 is modified to provide an annular zone 20 which surrounds the hole 16 at the entrance side of the laser beam 44 and which is color coded. The hole 16 thus shows a colored border in plan view. In order that the edges of several holes 16 together give a good perceptible color impression, the holes 16 in the perforated surface 14 are relatively narrow staggered according to the dot matrix R, as shown in FIG. 4. In FIG. 4, the holes 16 are exemplified in the dot matrix R in a hexagonal arrangement, in which the hole spacing D, which denotes the distance between the centers of individual holes 16, has been selected such that the areas of the edge effect are just touching. The hole spacing D thus corresponds to the dimension (C + 2B) + 2A of FIG. 3 (c). This is a marginal effect diameter E of FIG. 4. The holes 16 are arranged in FIG. 4 exactly at this distance E.

The arrangement of the holes in a dot matrix is optional. It is also a quasi-statistical arrangement of the holes possible, which complies with the stated area proportions of hole and surface.

The colored impression in the incident light, which arises when viewing the surface 16 by the juxtaposition of zones 20, of course, is also retained in other hole arrangements and hole spacings. From a hole spacing of the order of 2.5 times the rim diameter E, ie 2.5 times the sum of the maximum hole diameter (C + 2B) plus 2 times the zone width A, the colored impression becomes insufficient.

A green edge effect can be generated, for example, with the aid of the marking substance Manganese Ferrite F9900 M. Its color change goes from gray to green. Of course, other color changes are conceivable, for example, from red to gray with the dye Oxide Red PR222. Both dyes are from Cathay Industries. A color change from yellow to red is with the dye iron oxide yellow FeO (OH), available for example from Lanxess, possible. A color change from turquoise to black is with the dye copper (II) oxalate, available for example from Dr. med. Paul Lohmann GmbH, possible.

It is essential for the generation of the zone 20 towards the edge that the laser beam 44 has an intensity distribution which is not constant, ie has no top hat profile. Any intensity profile in which the intensity of the laser beam 44 decreases towards the edge of the beam cross-section with respect to the maximum value can be used for generating a zone 20, the type of intensity profile naturally being based on the width of the zone 20 relative to the maximum hole diameter (FIG. C + 2B) of each hole 16.

If an oblique hole edge is produced in the paper 18 by the laser beam, then the edge effect can also be formed along the entire hole edge, as can be seen in FIG. 5, if the marking substance 19 is not only at the

Surface but is placed in the volume 42 of the paper 18, as shown in Fig. 5 (a), or the paper 18 is directly modified.

By applying the paper 18 with the laser radiation 44, an oblique hole edge 46 is produced, as shown in FIGS. 5 (b) and (c). The energy threshold value required for the reaction of the paper 18 / marking substance 19 is thereby exceeded in an edge region 48 along the oblique hole edge 46 and the paper / marking substance is modified. Depending on the beam profile of the laser beam 44, a narrower or wider modified edge region 48 is thus produced, as illustrated in FIGS. 5 (b) and (c).

By way of example, FIGS. 5 (a) to (c) show only the creation of a hole 16, and also the volume provided with the marking substance 19 is only for a hole drawn. This was done for the sake of simplicity of illustration only. In fact, of course, as shown in Fig. 4, the holes are provided closely spaced in the surface 19. Instead of leaving the hole spacing constant, a specific design impression can be obtained by varying the hole spacing of the perforation, for example by lateral variation of the dot matrix R or by gridless arrangement of the holes. For example, it is possible to gradually increase the hole spacing in the region of the background of the surface 14 of FIG. 2 upwards. As a result, the color impression decreases towards the top, since in the surface 14 surface components increase that do not carry a zone 20. In this way, for example, using a red-dyeing dye, the impression of a sunset can be generated. A red coloration can be achieved by laser irradiation of a coating, for example containing Polyplast PY-383 or the already mentioned iron oxide yellow.

If, as shown in FIG. 6, the marking substance 19 is not provided in areas 14 in the area 14, for example not printed, only this part of the area 14 will be colored when the reflected light is observed. This encourages viewing in transmitted light, in which the entire motif encoded by the perforated surface 14 is then exposed. FIG. 6 shows exemplary strip-shaped regions 22 in which the marking substance 19 is missing.

FIG. 7 shows a development in which different motives are represented in the surface 14 by different patterns 24, 26 and 28, which differ in their geometry of the dot matrix. In the figure, a pentagonal grid Rl is used for the background, a square grid R2 for the elephant and a hexagonal grid R3 for the baby elephant. This makes the patterns stand out from each other, whereas In supervision a largely uniform color impression can be achieved. Alternatively, a good recognition of the three patterns 24, 26 and 28 can also be achieved, in particular in the case of comparatively large holes which are to be resolved by eye, whereas no subdivision appears in supervision. The geometry differences may also affect other parameters, as explained in the general part of the description.

FIG. 8 shows a plan view of a further embodiment of the security feature 12. Elements which correspond to those of the previous embodiments are provided with the same reference symbols, so that their description need not be repeated.

The security feature 12 includes edge-colored holes 16, which are arranged in a grid R. At individual positions in the grid R no hole 16, but only a colored dot 49 is formed. Thus, the area of holes 16 thus formed not only has an outer boundary, which has the shape of an "L" in Fig. 8, but also an inner boundary which effects codings 50. The dots 49 are kept in the same color as in Figs As a result, the colored dots 49 are not recognizable in plan view of the security feature 12. They appear in the same color as the rest of the area, which is colored by the colored edges of the holes 16 When viewed in transmitted light, the missing holes 16 are of course immediately noticeable, so that the codes 50 are clearly recognizable.

FIG. 9 shows a modification of the embodiment of FIG. 8 in that a multiplicity of inner boundaries are present in that the security feature 12 is made up of linearly aligned holes 16. alternates with linearly lined-up colored dots 49 is formed. Here, too, a motif is recognizable in plan view, for example in the form of a "P", which contains a line structure when viewed through the holes 16. The colored dots 49 are again colored in the color which the marking substance 19 has at the edges of the holes 16 The security element of Fig. 9 is thus made up of a plurality of surfaces, each of which is formed from linearly aligned holes 16. The embodiment of Fig. 9, as a modification to Fig. 8, does not represent a surface, the inner and outer borders but has a plurality of juxtaposed, here line-shaped surfaces, the optional feature being that these surfaces are arranged together with colored dots 49 in a common grid R with respect to the dots and the holes 9 designs can be combined and / or hidden information, such as numbers, geomet Rien or certain codes within the grid are generated, which are visible only in review of the holes 16. This is possible, for example, by hiding the colored dots 49 within a grid R (embodiment of FIG. 8) or by recognizing the adjacent and inked holes 16 only in transmitted light (FIG. 9).

In a further embodiment, the adjacent holes, which are directly adjacent to one another, can also be arranged in the form of a line which, for example, represents a colored border of a motif, this border then clearly emerging when viewed through the holes 16.

In the present case, a paper 18 has been mentioned by way of example as substrate of the banknote. Of course, a film or the like may be used as the substrate be used, for example, in a window area of a banknote.

LIST OF REFERENCE NUMBERS

10 banknote

12 security feature

14 area

16 holes

18 paper

19 marker

20 zone

22 area

24, 26, 28 patterns

30 intensity distribution

30 'heat energy distribution

32 cutting area

34, 34 'marking area

42 volumes

44 laser radiation

46 hole edge

48 edge area

49 colored dot

50 coding

A color effect width

B removal width

C hole diameter

D hole spacing

E edge effect diameter

El, El 'minimum energy

E2, E2 'reaction energy

R grid

Claims

Patent claims

1. A method for producing a security feature for a security element, a security paper or a data carrier, wherein a carrier (18) is provided, which is modifiable by laser radiation (44) in terms of its color, by the effect of distributed in the beam cross section (30) intensity distributed Laser radiation (44) holes (16) of certain hole diameter (C) are introduced into the carrier (18) having an edge, wherein at the same time due to the intensity distribution (30) over the beam cross-section in a peripheral zone (20 ) of the carrier (18) is modified by the laser radiation (44), so that the edge is colored, characterized in that the holes (16) perforate a surface (14), wherein within the surface (14) all adjacent holes (16) are spaced from each other at a hole center (D) center distance not greater than 2.5 times the sum of the maximum hole diameter diameter (C + 2B) and double zone width (A).

2. The method according to claim 1, characterized in that the hole spacing (D) is not greater than twice the sum of maximum hole diameter and double zone width (A).

3. A method for producing a security feature for a security element, a security paper or a data carrier, wherein a carrier (18) is provided, which is modifiable by laser radiation (44) with respect to its color, by the action in the beam cross section (30) intensified. Distributed laser radiation (44) holes (16) of certain hole diameter (C) in the carrier (18) having an edge, wherein at the same time due to the intensity distribution (30) over the beam cross-section in a peripheral zone (20 ) certain zone width (A) the carrier (18) is modified by the laser radiation (44) so that the edge is colored, characterized in that the holes (16) perforate a surface (14), wherein within the surface (14) the holes (16) account for at least 50% of the size of the area.

4. The method according to any one of the above claims, characterized in that between the adjacent holes (16) there is a minimum gap corresponding to twice the zone width (A).

5. The method according to any one of claims 1 to 4, characterized in that the surface has a first pattern (24) and at least one second pattern (26, 28), which with respect to the grid in which the holes are arranged, and / or the hole diameter (C) and / or the hole spacing (D).

6. The method according to any one of claims 1 to 5, characterized in that the carrier (18) is provided by the carrier (18) is provided with a marker (19) which is modifiable by the laser radiation (44) in terms of its color ,

7. The method according to claim 6, characterized in that the marking substance (19) is applied to the carrier (18), wherein it covers only a part of the surface (14), so that only a part of the holes (16) of the surface (16) 14) has the colored border.

8. The method according to any one of the above claims, characterized in that the holes (16) are arranged according to a dot matrix (R).

9. The method according to claim 8, characterized in that at several points (49) of the dot matrix (R) no holes (16) are formed and the carrier (18) is colored instead in the color of the edges, preferably the locations (49 ) of the dot matrix (R) encode a generally recognizable subject (50) or character or symbol.

10. Security feature for a security element, a security paper or a data carrier having a carrier (18), wherein the carrier (18) with respect to its color by laser radiation (44) is modifiable, in the carrier (18) holes (16) of certain hole diameter (C) are introduced, which have an edge, and in a zone (20) of certain zone width (A) surrounding the edge of the carrier (18) is modified, so that the edge is colored, characterized in that the holes ( 16) perforate a surface (14) and adjacent holes (16) within the surface (14) are spaced apart from one another at a hole center (D) of not more than 2.5 times the sum of the maximum hole diameter (C + 2B) and double zone width (A).

11. Security feature according to claim 10, characterized in that the hole spacing (D) is not greater than twice the sum of the maximum hole diameter (C + 2B) and double zone width (A).

12. Security feature for a security element, a security paper or a data carrier having a carrier (18), wherein the carrier (18) with respect to its color by laser radiation (44) is modifiable, in the carrier (18) holes (16) of certain Hole diameter (C) are introduced, which have an edge, and in a peripheral zone (20) of certain zone width (A) of the carrier (18) is modified so that the edge is colored, characterized in that the holes (16 ) an area (14) per- and within the area (14) the holes (16) make up at least 50% of the size of the area (14).

13. Security feature according to one of claims 10 to 12, characterized in that between the adjacent holes (16) there is a minimum gap which corresponds to twice the zone width (A).

14. Security feature according to one of claims 10 to 13, characterized in that the surface (14) has a first pattern (24) and at least one second pattern (26, 28), with respect to the grid in which the holes (16 ) are arranged, and / or the hole diameter (C) and / or the hole spacing (D) differ.

15. Security feature according to one of claims 10 to 14, characterized in that the carrier (18) is provided with a marking substance (19) which is modifiable in terms of its color by laser radiation (44).

16. Security feature according to claim 15, characterized in that the marker (19) covers only a part of the surface (14), so that only a part of the holes (16) has the colored edge.

17. Security feature according to one of claims 10 to 16, characterized in that the holes (16) are arranged according to a dot matrix (R).

18. Security feature according to claim 17, characterized in that at several points (49) of the dot matrix (R) no holes (16) are formed, but the carrier (18) is colored in the color of the edges, where preferably, the locations (49) encode a recognizable subject (50) or character or symbol.

19. Security element for security papers, security documents and the like having security feature (10) according to one of claims 10 to 18.

20. Security paper with a security element according to claim 19.

21. document of value or data carrier, in particular banknote (10) or identity card, with a security element according to claim 19.