EP3291999B1 - Security feature and method for producing the same - Google Patents

Description

The invention relates to a method for producing a security feature for a security element, a security paper or a data carrier having a carrier, wherein the carrier is modifiable by laser radiation in terms of its color, introduced by the action of laser beam in the beam cross-section intensity laser holes of certain hole diameter in the carrier be having 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 that is modifiable in color, in the carrier holes of certain hole diameter are introduced, which have an edge, and in a surrounding zone of the edge certain zone width of the carrier is modified so that the edge is colored, as well as a security element, a security paper and a document of value 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. For example, in the document DE 43 34 848 C1 describes a security with a closed by a transparent cover film window-like opening, which can be generated by a laser cutting process.

The WO 2009/003587 A1 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 from the WO 2009 / 003588A1 However, several laser beams of different intensities are required in order to achieve a particularly large and thus well-recognizable color effect.

Laser radiation-sensitive marking substances are known, for example, from the following publications: EP 1657072 B1 . EP 000002332012 B1 . US 7270919 . US 7485403 . US 7998900 . US 8021820 . US8048608 . US8048605 . 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 laser radiation 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 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 in a relation to the hole center hole spacing from each other, which is not greater than 2.5 times the sum of maximum hole diameter and 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-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 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 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 a certain hole diameter are introduced, which have an edge, and in a zone of certain zone width surrounding the edge, the support is modified so that the edge is colored, the holes being arranged overlapping one surface and within the surface all adjacent holes are arranged in a hole center distance spaced from each other which is not larger as 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 respect to an outer or inner boundary. The outer boundary of the surface can then be a motif encode. 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. If the surface has an inner boundary, as it is called by way of example, i. at least one recess, and an outer boundary, the holes lying at the respective boundary are adjacent to the holes lying within the surface, of course not to the area outside the boundary, at which the surface ends inside or outside.

An area outside the boundary of the area may preferably be provided with a coloration which is similar to that of the hole edges. Then, in plan view, the effect that the boundary of the surface is at least partially not visible, in view when the holes are visible, but clearly emerges.

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 sites may in a further preferred embodiment be colored in the color of the hole edges, e.g. correspondingly arranged points, and most preferably a motif, encode sign or symbol, which is not or poorly in plan view, but clearly visible in the see through.

The invention uses a special arrangement of the holes in the perforated surface to those in the WO 2009/003587 A1 to reinforce and emphasize the color effect described. The term "color" is not limited to a colorful impression, but may also include black. The inventive perforation of the surface creates a colorful impression without a viewer would have to search for a colored hole edge first, which could well be the case with a single hole or a single opening. In transmitted light, on the other hand, a transparent impression is conveyed. 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 well perceived in 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 on the center of the hole, so the indication of the hole spacing as the distance between the hole centers of adjacent holes, achieved the feature that the hole spacing related to the hole center is not greater than 2.5 times the sum of hole diameter and double zone width, that the colored 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 the 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 a further 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 ensured.

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 marking substance into the volume of the paper substrate in a dipping bath or to mix the paper substrate, e.g. in a size press, to impregnate with the marker.

Of course, a carrier may also be laser-irradiated without additional tagging material. 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 may be formed thermoreactive or the marker may 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 colored 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 particularly for the machine 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. When using several markers, these can come to lie next to each other as well as 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 done with laser radiation in the ultraviolet, visible or infrared spectral range, for example with a CO ₂ laser of a wavelength of 10600 nm.

In a further 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 CO ₂ laser. Specific, non-limiting examples of pigment-free laser-modifiable markers are in the references WO 02/101462 A1 . US 4343885 and EP 0290750 B1 specified, the disclosure of which is included in the present description in this regard.

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 may for example be 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 by the method described, in particular a value document such as a banknote, identity card or the like, wherein the data carrier has 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 true to scale and proportion has been dispensed with in order to increase the clarity.

Fig. 1

eine schematische Darstellung einer Banknote mit einem Sicherheitsmerkmal,

Fig. 2

eine Detailaufsicht auf das Sicherheitsmerkmal der Fig. 1,

Fig. 3(a)-(c)

die Erläuterung der Herstellung des Sicherheitsmerkmals, wobei Fig. 3(a) schematisch eine räumliche Energieverteilung eines Laserstrahls, Fig. 3(b) eine räumliche Verteilung der beim Schneiden entstehenden Wärmeenergie, und Fig. 3(c) detailliert die Abmessungen von durch den Laserstrahl erzeugten Löchern zeigt,

Fig. 4

eine Detailansicht auf das Sicherheitsmerkmal,

Fig. 5(a)-(c)

Querschnittdarstellungen eines Lochs des Sicherheitsmerkmales, wobei Fig. 5(a) die Situation vor der Einstrahlung der Laserstrahlung zeigt und Fig. 5(b) und (c) zwei Löcher mit unterschiedlich breitem Randeffekt zeigen, und

Fig. 6 - 9

Aufsichten auf ein Sicherheitsmerkmal nach weiteren Ausführungsformen.

Show it:

Fig. 1

a schematic representation of a banknote with a security feature,

Fig. 2

a close attention to the security feature of Fig. 1 .

Fig. 3 (a) - (c)

the explanation of the production of the security feature, wherein Fig. 3 (a) schematically a spatial energy distribution of a laser beam, Fig. 3 (b) a spatial distribution of the heat energy generated during cutting, and Fig. 3 (c) detailed the Dimensions of holes created by the laser beam,

Fig. 4

a detailed view of the security feature,

Fig. 5 (a) - (c)

Cross-sectional views of a hole of the security feature, wherein Fig. 5 (a) the situation before the irradiation of the laser radiation shows and Fig. 5 (b) and (c) show two holes with different width edge effect, and

Fig. 6-9

Supervision of a security feature according to further embodiments.

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

In Fig. 2 is the security feature 12 used in Fig. 1 is shown only schematically, shown in more detail. 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 multi-part, so that the outline of an elephant and an elephant baby in front of a semi-circular background surface 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, i. the introduction of a hole and the modification of the marker at the edge happens for each hole 16 simultaneously.

The principle of the simultaneous production of the holes 16 and their edge design is in Fig. 3 (a) illustrated. 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 E1 required to cut the paper 18. With E2 is in Fig. 3 (a) denotes a reaction energy of the effect pigments of the marking substance, when said color change occurs beyond said. 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 a color change of the effect pigments is induced in this region 34 but paper 18 is not cut.

The paper 18 is therefore discolored when laser cutting by the laser beam in a zone at the edge of each hole 16 in perfect registration to the hole 16. 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 marking substance 19 can be applied to the paper 18, for example by printing it on (cf. Fig. 3 (c) ), or can be introduced into the volume. This can already be done during papermaking by admixture of the effect pigments to the paper pulp during sheet formation or else subsequently in an immersion bath or by impregnation, for example 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 is understood that two or more effect pigments with different threshold energies or a combination of visually and mechanically detectable effect pigments can also be used to produce a plurality of registered 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. Also, such markers can, for example, as intaglio or printing ink, printed on the paper 18 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 CO 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 area of the opening may optionally be even larger than the beam extent, as in FIG Fig. 3 (b) clarified.

Fig. 3 (b) schematically shows the spatial distribution 30 'of the heat energy when cutting an opening with the laser beam of Fig. 3 (a) is produced. As if from a comparison of FIGS. 3 (a) and (b) if applicable, the heated area may extend beyond the jet diameter due to heat conduction.

As already at Fig. 3 (a) described, the paper 18 is cut in the cutting region 32, since there exceeds the laser energy E required for cutting threshold energy E1. Reacts the paper 18 or the marker 19 now at least also on the heat energy generated during cutting, then results in the for Fig. 3 (b) assumed ratios a marking region 34 ', the extent of which can easily be greater than the cross section of the laser beam. 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 with the intensity distribution 30 on the paper 18. In this embodiment, the paper 18 is coated with the marking substance 19. A laser beam 44 intersects a hole 16 having a hole diameter C, the hole being cross-sectioned as in FIG Fig. 3 (d) to see, exemplary conical runs. As hole diameter is in Fig. 3 (d) the minimum hole diameter C is recorded, 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, such as Fig. 4 shows. In Fig. 4 For example, the holes 16 are exemplified in the dot grid R in a hexagonal arrangement in which the hole spacing D, which denotes the distance between the centers of individual holes 16, has been chosen so that the areas of 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 in Fig. 4 arranged 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 toward the edge of the beam cross-section versus the maximum value may be used to create a zone 20, the type of intensity profile naturally being the width of the zone 20 relative to the maximum hole diameter (C + 2B) of each hole 16.

If an oblique hole edge in the paper 18 is generated by the laser beam, then the edge effect can also be formed along the entire hole edge, as in FIG Fig. 5 it can be seen when the marker 19 is incorporated not only on the surface, but in the volume 42 of the paper 18, as shown in FIG Fig. 5 (a) is shown, or the paper 18 is modified directly.

By applying the paper 18 with the laser radiation 44, an oblique hole edge 46 is generated, as it Fig. 5 (b) and (c) demonstrate. 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 is the case with the laser beam 44 Fig. 5 (b) and (c) illustrate.

The Fig. 5 (a) to (c) show only the production of a hole 16 by way of example, 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, the holes are as in Fig. 4 shown closely spaced in the surface 19 provided.

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 in the area of the background of the surface 14 of the Fig. 2 upward to increase the hole spacing gradually. 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.

Will, as in Fig. 6 shown, the marker 19 not regionally provided in the area 14, for example, not printed, shows in reflected light viewing only this part of the surface 14 colored. 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 marker 19 is missing.

Fig. 7 shows a development in which in the area 14 different motifs are represented by different patterns 24, 26 and 28, which differ in their geometry of the dot matrix. In the figure, a pentagonal grid R1 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 with comparatively large holes which are to be resolved with the eye, whereas no distinction 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 numerals, 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. The thus formed surface of holes 16 thus has not only an outer boundary, the in Fig. 8 has the shape of an "L" but also has an inner boundary that effects encodings 50. The dots 49 are held in the same color as the marker 19 of the holes 16 is colored. As a result, the colored dots 49 can not be seen 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 of course fall immediately, so that the codes 50 are clearly visible.

Fig. 9 shows a modification of the embodiment of the Fig. 8 in that a plurality of inner boundaries are present, by the security feature 12 alternates of line-lined holes 16 formed with line-shaped colored dots 49 is formed. Again, a motif is visible 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 marker 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 of line-shaped juxtaposed holes 16. The embodiment of the Fig. 9 thus makes a modification Fig. 8 not a surface having inner and outer boundaries, but a plurality of adjacent, 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 points and the holes ,

Due to the embodiments according to Fig. 8 and 9 For example, designs may be combined and / or hidden information, such as numbers, geometries, or specific encodings within the raster, that are visible only when viewed through the holes 16. This is possible for example by the colored dots 49 are hidden within a grid R (embodiment of the Fig. 8 ) or by the adjacent and colored holes 16 are visible 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

bill

12

safety feature

14

surface

16

hole

18

paper

19

tracer

20

Zone

22

Area

24, 26, 28

template

30

intensity distribution

30 '

Thermal energy distribution

32

cutting area

34, 34 '

marking region

42

volume

44

laser radiation

46

hole edge

48

border area

49

colored dot

50

encoding

A

Color effect Width

B

Abtragsbreite

C

Hole diameter

D

hole spacing

e

Edge effect diameter

E1, E1 '

minimum energy

E2, E2 '

reaction energy

R

grid

Claims (21)

1. Method for producing a security feature for a security element, a security paper or a data carrier, wherein a substrate (18) is provided, the colour of which can be modified by laser radiation (44), holes (16) that have a specific hole diameter (C) and have a rim are introduced into the substrate (18) by the action of laser radiation (44) of which the intensity is distributed in the beam cross section (30), wherein at the same time, because of the intensity distribution (30) over the beam cross section, the substrate (18) is modified by the laser radiation (44) in a zone (20) of specific zone width (A) surrounding the rim, so that the rim is coloured, characterized in that the holes (16) perforate an area (14), wherein, within the area (14), all the adjacent holes (16) are arranged with 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 (C+2B) and twice the zone width (A).
2. Method according to Claim 1, characterized in that the hole spacing (D) is no greater than twice the sum of the maximum hole diameter and twice the zone width (A).
3. Method for producing a security feature for a security element, a security paper or a data carrier, wherein a substrate (18) is provided, the colour of which can be modified by laser radiation (44), holes (16) that have a specific hole diameter (C) and have a rim are introduced into the substrate (18) by the action of laser radiation (44) of which the intensity is distributed in the beam cross section (30), wherein at the same time, because of the intensity distribution (30) over the beam cross section, the substrate (18) is modified by the laser radiation (44) in a zone (20) of specific zone width (A) surrounding the rim, so that the rim is coloured, characterized in that the holes (16) perforate an area (14), wherein, within the area (14), the holes (16) make up at least 50% of the size of the area.
4. Method according to one of the above claims, characterized in that there is a minimum gap between the adjacent holes (16) which corresponds to twice the zone width (A).
5. Method according to one of Claims 1 to 4, characterized in that the area has a first pattern (24) and at least one second pattern (26, 28), which differ with regard to the grid in which the holes are arranged and/or the hole diameter (C) and/or the hole spacing (D).
6. Method according to one of Claims 1 to 5, characterized in that the substrate (18) is provided in which by the substrate (18) is provided with a marking substance (19), the colour of which can be modified by the laser radiation (44).
7. Method according to Claim 6, characterized in that the marking substance (19) is applied to the substrate (18), wherein it covers only part of the area (14), so that only some of the holes (16) of the area (14) have the coloured rim.
8. Method according to one of the above claims, characterized in that the holes (16) are arranged in accordance with a dot matrix (R).
9. Method according to Claim 8, characterized in that at a plurality of locations (49) of the dot matrix (R), no holes (16) are formed and, instead, the substrate (18) is coloured in the colour of the rims, wherein the locations (49) of the dot matrix (R) overall preferably encode a motif (50) or character or symbol that can be seen in transmission.
10. Security feature for a security element, a security paper or a data carrier, which has a substrate (18), wherein the colour of the substrate (18) can be modified by laser radiation (44), holes (16) that have a specific hole diameter (C) and have a rim are introduced into the substrate (18), and the substrate (18) is modified in a zone (20) of specific zone width (A) surrounding the rim, so that the rim is coloured, characterized in that the holes (16) perforate an area (14) and, within the area (14), all the adjacent holes (16) are arranged with 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 (C+2B) and twice the zone width (A).
11. Security feature according to Claim 10, characterized in that the hole spacing (D) is no greater than twice the sum of the maximum hole diameter (C+2B) and twice the zone width (A).
12. Security feature for a security element, a security paper or a data carrier, which has a substrate (18), wherein the colour of the substrate (18) can be modified by laser radiation (44), holes (16) that have a specific hole diameter (C) and have a rim are introduced into the substrate (18), and the substrate (18) is modified in a zone (20) of specific zone width (A) surrounding the rim, so that the rim is coloured, characterized in that the holes (16) perforate an area (14) 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 there is a minimum gap between the adjacent holes (16) which corresponds to twice the zone width (A).
14. Security feature according to one of Claims 10 to 13, characterized in that the area (14) has a first pattern (24) and at least one second pattern (26, 28), which differ with regard to the grid in which the holes (16) are arranged and/or the hole diameter (C) and/or the hole spacing (D).
15. Security feature according to one of Claims 10 to 14, characterized in that the substrate (18) is provided with a marking substance (19), the colour of which can be modified by laser radiation (44).
16. Security feature according to Claim 15, characterized in that the marking substance (19) covers only part of the area (14), so that only some of the holes (16) have the coloured rim.
17. Security feature according to one of Claims 10 to 16, characterized in that the holes (16) are arranged in accordance with a dot matrix (R).
18. Security feature according to Claim 17, characterized in that at a plurality of locations (49) of the dot matrix (R), no holes (16) are formed and, instead, the substrate (18) is coloured in the colour of the rims, wherein the locations (49) preferably encode a motif (50) or character or symbol that can be seen in transmission.
19. Security element for security papers, documents of value and the like having a security feature (10) according to one of Claims 10 to 18.
20. Security paper having a security element according to Claim 19.
21. Document of value or data carrier, in particular banknote (10) or identity card, having a security element according to Claim 19.

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