EP2164708B1 - Security feature and method for producing the same - Google Patents

Abstract

A method for manufacturing a security feature for a security element, a security paper or a data carrier that exhibits a substrate into which at least one through opening and at least one marking in registration with the through opening are to be introduced. The method includes the steps of providing a substrate with a laser-modifiable marking substance at least in the region of the marking to be produced and, in the same operation, introducing at least one through opening into the substrate by the action of laser radiation at higher laser power and modifying the laser-modifiable marking substance in the marking region by the action of laser radiation at a lower laser power to produce at least one marking in registration with the through opening.

Description

The invention relates to a security feature for a security element, a security paper or a data carrier which has a carrier, in which at least one through opening and at least one passport registered to the continuous opening are to be introduced. In particular, the invention relates to a method for producing such a security feature and to a security element, a security paper and a data carrier having 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 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.

From the WO 2005/108109 A1 For example, a security document, such as a banknote, passport or the like, comprising a security paper and a laser generated mark, wherein the security paper has at least a portion having a coating, and the mark extends beyond the boundary region between the coating and security paper.

The publication EP 0 956 975 A2 relates to a copy protection element comprising a metal layer and another layer. The physical / optical properties of the further layer are such that with the aid of a laser beam, markings introduced into the copy protection element can not be reproduced by electrophotography.

The publication EP 1 661 729 A2 relates to the laser marking of value documents, which is based on interaction of the laser radiation with the ink systems used.

The publication WO 02/03104 A2 describes a method for producing a security feature in which a substrate coated with a metal layer is provided with throughgoing or non-penetrating openings by means of laser radiation. The metal layer is vaporized by the action of the laser radiation and thus completely removed.

Based on this, the present invention has the object, safety elements, security papers and data carriers of the type mentioned in terms of their Nachahnungssicherheit on to improve.

This object is achieved by the method having the features of the main claim. A corresponding security element, a security paper and a data carrier with such a security feature are specified in the independent claims. Further developments of the invention are the subject of the dependent claims.

• a) der Träger zumindest im Bereich der zu erzeugenden Markierung mit einem lasermodifizierbaren Markierungsstoff versehen wird, und
• b) im selben Arbeitsgang
• b1) durch Einwirkung von Laserstrahlung bei höherer Laserleistung zumindest eine durchgehende Öffnung in den Träger eingebracht wird, und
• b2) durch Einwirkung von Laserstrahlung bei niedrigerer Laserleistung der lasermodifizierbare Markierungsstoff im Markierungsbereich modifiziert und so zumindest eine zur durchgehenden Öffnung gepasserte Markierung erzeugt wird.

According to the invention, it is provided in a generic method that

• a) the support is provided with a laser-modifiable marking substance at least in the region of the marking to be generated, and
• b) in the same operation
• b1) by the action of laser radiation at higher laser power at least one through opening is introduced into the carrier, and
• b2) the laser-modifiable marking substance in the marking region is modified by the action of laser radiation at a lower laser power and thus at least one mark registered for the continuous opening is produced.

The order of steps b1) and b2 is arbitrary. It is initially step b1) and then step b2) or only step b2) and then step b1) are executed.

The inventive method relates to the production of a security feature that in a separate security element for application to or for insertion in a data carrier, in a security paper or a security film for the production of documents of value or the like, or in a data carrier, such as a banknote, identity card or the like, may be present. It is only essential that the security element, security paper or the data carrier provides a carrier for the security feature, in which the through openings and the passported markings are introduced. Even though, for the sake of simplicity, the term "openings" and "markings" usually refers to the following, it is always understood that according to the invention Also, only a single opening and a single mark can be provided in the carrier.

In an advantageous variant of the invention, at least one continuous opening and at least one registered marking are produced without spacing into one another. This can be achieved, for example, by continuously guiding the laser beam along the aperture to be cut and the marker to be inserted, thereby reducing the laser energy at the junction of the aperture to be cut and the marker to be inserted, and of high laser energy similar to that required for cutting the carrier exceeds the energy required to a lower energy level, which is no longer sufficient to cut the carrier, but is still above the reaction energy of the marker. By this measure, the opening and the marking are generated in the same operation with the same laser beam and are therefore highly accurately matched.

According to a further advantageous variant of the invention, at least one through opening and at least one registered marking can be produced spaced apart from one another. For this purpose, with continuous guidance of the laser beam, the laser energy in the intermediate space between the opening to be cut and the mark to be introduced can be lowered to zero or at least to a value below the reaction energy of the marking substance. As a result, the opening, gap and marking are generated in the same operation with the same laser beam and are so highly accurately matched.

The support can be kept free of laser-modifiable marker in the area of the through openings, so that excluded is that the edge area of the openings is modified by the laser beam.

Alternatively, the carrier can also be provided with laser-modifiable marking material in the area of the through openings, so that the laser-modifiable marking substance in the vicinity of the openings is modified by the cutting laser beam when introducing the through openings. The phrase "near area of the openings" also includes, in addition to the edge area directly adjoining the opening, an area which, with a certain small distance, lies close to the opening. The small distance can be a few tenths of a millimeter or a few millimeters, depending on the application.

In order 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 impregnate the paper substrate in a size press with the marking substance. If the carrier is formed from a plastic film, the marking substance can likewise be introduced into the volume of the film during the production of the film or subsequently by means of 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, magnetic, electrical or luminescent properties are changed by the action of the laser radiation. Security features having openings with such a laser-modified marker region can be used in particular for mechanical authentication. 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.

The through openings can be produced in particular in the form of perforations, cuts or extended window areas.

In the variants of the invention in which the carrier is also provided with a laser-modifiable marking substance in the region of the openings, it can be modified in particular in an edge region adjoining the openings to be produced by the action of laser radiation.

According to an advantageous variant of the invention, laser-modifiable effect pigments are used as the laser-modifiable marker. Such effect pigments are available to the person skilled in the art with different properties, in particular with regard to their body color, the color change under laser action, the threshold energy and the required laser wavelength. Also effect pigments, which are not (only) their visible color, but their infrared-absorbing, magnetic, electrical laser irradiation or change luminescent properties, are known in the art. The modification of the effect pigments can be made with laser radiation in the ultraviolet, visible or infrared spectral range, for example, a CO ₂ laser of a wavelength of 10.6 microns.

In a further likewise advantageous variant of the invention, a pigment-free laser-modifiable marker is used. Pigment-free marking substances can also be applied to the support or introduced into the support volume, for example as a stitch 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 10.6 μm radiation of a CO ₂ laser. Specific, non-limiting examples of pigment-free, laser-modifiable markers are in the documents WO 02/101462 A1 . US 4,343,885 and EP 0290 750 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 having a security feature produced according to the method described, wherein the security element has a carrier in which at least one through opening and at least one mark registered through the opening are introduced by the action of laser radiation, and the contains a laser-modified marker in the region of the marker. Such a security element can, 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, introduced by the action of laser radiation at least one through opening and at least one passported to the continuous opening marker and which contains a laser-modified marker in the region of the marking. Instead of introducing the openings 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 document of value, such as a banknote, identity card or the like, wherein the data carrier has a carrier in which by the action of laser radiation at least one through opening and at least one through opening and a laser-modified marker is included in the region of the marker. Instead of introducing the openings directly into the data carrier, the latter can also be provided with a security element according to the invention or can be produced from a security paper according to the invention.

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 er- findungsgemäßen Merkmalsbereich,

Fig. 2

eine Detailaufsicht auf den Merkmalsbereich von Fig.1,

Fig. 3

schematisch den zeitlichen Verlauf der Laserenergie bei der Erzeugung einer durchgehenden Öffnung und einer gepasser- ten Markierung in einem erfindungsgemäßen Verfahren, und

Fig. 4 und 5

Detailansichten auf Merkmalsbereiche nach weiteren Ausfüh- rungsbeispielen der Erfindung.

Show it:

Fig. 1

1 a schematic representation of a banknote having a feature area according to the invention,

Fig. 2

a detailed supervision of the feature area of Fig.1 .

Fig. 3

schematically the time course of the laser energy in the generation of a through-hole and a potted mark in a method according to the invention, and

4 and 5

Detailed views of feature areas according to further embodiments of the invention.

The invention will now be explained using the example of a banknote. The Figures 1 and 2 show a schematic representation of a banknote 10, which in an in Fig. 2 more precisely, the feature area 12 according to the invention is provided with a laser hole and an associated, highly precisely matched marking.

With reference to the supervision of Fig. 2 was in the feature area 12 by the action of laser radiation, a through opening 14 cut into the paper substrate 16 of the banknote 10. The opening 14 is at several points directly into a colored, for example, red mark 18, which is formed in the embodiment by a series of patch pentagons, and which is highly precisely adapted to the opening 14.

To produce the aperture 14 and mark 18, the paper substrate 16, prior to laser cutting, has been formed in the region 20 of FIG Mark provided with a laser-modifiable marker, which shows the desired color change upon exposure to laser radiation.

During laser cutting, the laser power is varied selectively to alternate between cutting the paper and modifying the marker. Fig. 3 schematically shows the time course 30 of the laser energy during laser cutting. E _S is the threshold energy required to cut the paper substrate 16, E _{M is} the reaction energy of the marker, when exceeded, the desired reaction, in the embodiment of the red color change occurs.

During a time interval t _H , a laser beam with a high laser energy E _{H is} generated, which exceeds the threshold value E _S for cutting the paper substrate 16, and the laser beam is guided in such a way that a section 14-1 (FIG. Fig. 2 ) of the opening 14 is cut.

Then, the laser power is reduced for a time interval t _L to a lower laser energy E _L , which is no longer sufficient for cutting the substrate 16, but is still above the reaction energy E _{M of} the marker. In this case, the laser beam is guided in the marking area 20 in the form of a pentagonal section 18-1 of the desired marking 18.

Subsequently, the laser energy is again increased to the laser energy E _H for a time interval t _H and the next section 14-2 of the opening is cut. In a further time interval t _L with low laser energy E _L , the next portion 18-2 of the marker 18 is generated. This process continues until the entire opening 14 and the entire marking 18 are completed are placed. Since the opening 14 and the mark 18 are produced in the same operation with the same laser beam, they are highly precisely matched.

Fig. 4 shows a further embodiment of the invention, in which the through-hole 14 and the highly accurately registered mark 28 are generated spaced from each other. For this purpose, the laser energy in a time interval t ₀ between the laser cutting (t _H ) and the laser marking (t _L ) to zero or at least a value E ₀ , which is below the reaction energy E _M , lowered and the laser beam in this time interval from the edge 14th -R of the opening 14 to a starting point 28-R of the marking section to be introduced. After completion of the marking section with laser energy E _L , the laser energy is lowered back to E ₀ , the laser beam is returned to the edge point 14-R of the opening 14 and the cutting of the opening continued. In this way, an opening 14 and a highly accurately registered, spaced mark 28 are formed.

At the in Fig. 5 shown further embodiment, not only the region of the mark to be generated, but also the region of the opening to be introduced is provided with the laser-modifiable marker. In this way, in addition to the as in the embodiment of Fig. 2 generated mark 18 when cutting the opening 14 creates an effect edge 38, which is perfectly matched to the opening 14 and the mark 18.

The emergence of this effect edge 38 during laser cutting results from the essentially Gaussian spatial energy distribution of the cutting laser beam. While in an inner portion of the cutting laser beam, the threshold energy Es needed to cut the substrate 16 is exceeded, the energy density of the cutting laser beam falls outside the laser spot continuously down to zero. There is therefore an outer region of the cutting laser beam in which the local energy lies between E _M and Es, so that a color change of the marker is induced in this region, but the substrate is not cut. In this way, the paper substrate 16 is laser engraved in an edge region 38 of the cut opening 14 in perfect registration with the opening 14 and the mark 18. The width of the colored edge region 38 depends on the beam profile of the laser beam, the reaction energy of the marker used and the material properties of the substrate 16.

In addition to the modification of the marker by the laser radiation itself, a modification by the heat generated during laser beam cutting comes into question. In this way, the modified edge region of the opening may even be greater than the beam extent.

It is also possible that the marking material is removed or destroyed directly next to the cut edge of the opening 14 and is modified only from a certain small distance from the cutting edge. If, for example, the marking substance is ablated or destroyed above a laser energy E _D , where E _M <E _D <E _S , then the marking substance is located in an inner edge region of the laser beam in which the local energy E _D <E <E _S , removed and modified in a more remote edge region of the laser beam, in which E _M <E <E _D applies. During laser cutting, an opening 14 is then formed which, in addition to the highly precisely matched marking 18, has a perfectly adjusted modification region which circulates at a small distance around the edge of the opening 14.

Claims (16)

1. A method for manufacturing a security feature, for a security element, a security paper or a data carrier, that exhibits a substrate (16) into which at least one through opening (14) and at least one marking (18) in registration with the through opening (14) are to be introduced, wherein, in the method,

   a) the substrate (16) is provided (20) with a laser-modifiable marking substance at least in the region of the marking (18) to be produced, and

   b) in the same operation

   b1) at least one through opening (14) is introduced into the substrate (16) by the action of laser radiation at higher laser power, and

   b2) the laser-modifiable marking substance is modified in the marking region (20) by the action of laser radiation at lower laser power and, in this way, at least one marking (18) in registration with the through opening is produced.
2. The method according to claim 1, characterized in that at least one through opening (14) and at least one registered marking (18) are produced transitioning into one another without spacing.
3. The method according to claim 1 or 2, characterized in that at least one through opening (14) and at least one registered marking (28) are produced spaced apart.
4. The method according to at least one of claims 1 to 3, characterized in that the substrate (16) is kept free from laser-modifiable marking substance in the region of the through openings (14).
5. The method according to at least one of claims 1 to 3, characterized in that the substrate (16) is provided with laser-modifiable marking substance also in the region of the through openings (14) such that the laser-modifiable marking substance is modified in the vicinity (38) of the openings (14) by the same laser beam when introducing the through openings (14).
6. The method according to at least one of claims 1 to 5, characterized in that the substrate (16) is coated with the marking substance, or that the marking substance is introduced into the volume of the substrate (16).
7. The method according to at least one of claims 1 to 6, characterized in that the substrate (16) is formed from paper or from a plastic foil.
8. The method according to at least one of claims 1 to 7, characterized in that the substrate (16) is provided with a marking substance whose visible color is changed by the action of the laser radiation.
9. The method according to at least one of claims 1 to 8, characterized in that the substrate (16) is provided with a marking substance whose infrared-absorbing, magnetic, electrical or luminescent properties are changed by the action of the laser radiation.
10. The method according to at least one of claims 1 to 9, characterized in that the through openings (14) are produced in the form of perforations, cuts or expansive window regions.
11. The method according to at least one of claims 5 to 10, characterized in that the laser-modifiable marking substance is modified by the action of laser radiation in an edge region (38) of the openings (14) that immediately adjoins the openings (14) to be produced.
12. The method according to at least one of claims 1 to 11, characterized in that laser-modifiable effect pigments are used as the laser-modifiable marking substance, or that a pigment-free laser-modifiable marking substance is used as the laser-modifiable marking substance.
13. The method according to at least one of claims 1 to 12, characterized in that laser radiation in the ultraviolet or visible spectral range is used to introduce the openings and to modify the marking substance, or that laser radiation in the infrared spectral range, especially laser radiation of a CO₂ laser at a wavelength of about 10.6 µm, is used to introduce the openings (14) and to modify the marking substance.
14. A security element for security papers, value documents and the like, having a substrate (16) into which at least one through opening (14) and at least one marking in registration (18) with the through opening (14) are introduced by the action of laser radiation, and having a laser-modified marking substance in the region of the marking, manufacturable according to one of claims 1 to 13.
15. A security paper for manufacturing value documents or the like, having a substrate (16) into which at least one through opening (14) and at least one marking (18) in registration with the through opening (14) are introduced by the action of laser radiation, and having a laser-modified marking substance in the region of the marking, manufacturable according to one of claims 1 to 13.
16. A data carrier, especially a value document, such as a banknote, identification card or the like, having a substrate (16) into which at least one through opening and at least one marking (18) in registration with the through opening are introduced by the action of laser radiation, and having a laser-modified marking substance in the region of the marking, manufacturable according to one of claims 1 to 13.

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