EP1691989B1 - Data carrier, and method for the production thereof - Google Patents

Abstract

The invention relates to a multilayer security element having a metal layer ( 20 ) into which are introduced, by a laser beam, identifiers ( 16 ) in the form of patterns, letters, numbers and/or images, the metal layer ( 20 ) being disposed between two translucent coating layers ( 26, 28 ). The identifiers ( 16 ) in the metal layer ( 20 ) display a watermark effect in which they appear, when viewed in transmitted light, as a positive image, and when viewed in reflected light, as a negative image.

Description

The invention relates to a multilayer security element with a metal layer into which markings in the form of patterns, letters, numbers and / or images are introduced by a laser beam. The invention further relates to a method for producing such a security element as well as a data carrier which is equipped with such a security element.

It is known to personalize ID cards, such as credit cards, bank cards or identity cards, by means of laser engraving. In personalization by laser engraving, the optical properties of the card material in the form of a desired marking are irreversibly changed by suitable guidance of a laser beam. To complicate the reproduction of such ID cards with modern copying machines, personalization data is often placed in metallic layers against a dark background. Since the metallic background leads to a directed reflection of the incident light rays and the detector in copying machines is usually arranged so that it can only detect the light scattered diffusely by the original, the metallic surfaces appear like the introduced markings in the copy throughout black.

From the German patent DE 31 51 407 C1 is a multi-layered ID card is known, which is equipped with a plastic sheet as a recording medium. The plastic film appears completely transparent in the visible wavelength range, but absorbs so strongly at the wavelength of an infrared laser used for writing information that localized blackening of the film results due to the action of the laser beam. This allows images and / or data to be written in the plastic film with a good resolution.

From the DE 10050553 A1 are a multilayer, can be labeled with a laser film and a multilayer security element according to the preamble of claim 1 known.

Proceeding from this, the object of the invention is to provide a security element for data carriers, in particular for value documents, such as an identification card, a banknote or the like, which is provided with identifications in the form of patterns, letters, numbers and / or images, and at the same time provides high quality protection against photographic or xerographic reproduction.

This object is achieved by the security element having the features of the main claim. A method for producing such a security element as well as a data carrier equipped with such a security element are specified in the independent claims. Further developments of the invention are the subject of the dependent claims.

The security element according to the invention is based on the prior art in that the metal layer is arranged between two translucent cover layers whose light transmittance in the visible spectral range is less than 10%, whereby the markings in the metal layer show a watermark effect, when viewed in transmitted light in Positive representation and when viewed in incident light in negative representation appear.

In the context of the present description, "transparency" denotes the full transparency of a material, "translucent" means translucent in the sense of a certain translucency, but unlike transparent materials, objects located behind translucent materials are not or only diffusely recognizable, and "opaque" denotes the Opacity of a material.

Due to the translucence of the cover layers, the introduced gaps in the metal layer appear bright in transmitted light, while the remaining metal layer areas appear dark. This appearance is referred to herein as a positive representation of the markings. In reflected light, however, the gaps in the metal layer appear darker than the metal layer areas, so that the image impression is reversed to a negative image. This reversal corresponds to the classical watermark effect in paper and is therefore also referred to as a watermark effect, even if the production is fundamentally different compared to the watermark in the paper.

The light transmittance of the cover layers is preferably to be optimized so that a good contrast of the areas modified by laser radiation is achieved relative to the unirradiated areas. In a particularly advantageous embodiment of the invention, the light transmittance of the translucent cover layers in the visible spectral range is less than 10%, preferably less than 5%.

The translucent cover layers may be colored and appear white or pastel-colored, especially in reflected light.

The introduction of the markings into the metal layer can advantageously take place via a local material removal in the metal layer or via a local conversion of the metal into a transparent or translucent modification.

The metal layer is preferably an aluminum, copper or gold layer. Preferably, the metal layer has a thickness of about 5 to 10 microns. The cover layers are preferably layers of paper, PVC, polyester, PC or compounds thereof. The layer thickness of the cover layer preferably varies between about 100 and 250 μm.

Preferably, the translucent cover layers are chosen so that they have no appreciable absorption at the wavelength of the laser radiation used for the marking. The laser wavelength is expediently chosen in the infrared spectral range, for example at about 1.06 μm (Nd: YAG laser or Nd: glass laser) or at about 10.6 μm (CO ₂ laser). For these wavelengths, the person skilled in a variety of materials are available, on the one hand for data carriers, such as identity cards, are suitable and on the other hand connect the required translucency in the visible spectral range with the low absorption at the laser wavelength.

It is also conceivable, however, for at least one of the cover layers to absorb laser light and thus to look specifically from the side with the absorbing cover layer, a classic image produced by blackening is present, viewed from the other side, a transmitted-light effect is visible.

The markings may include personal data, such as a signature, a date of birth, a portrait or the like, and / or data-related data such as a serial number, a period of validity, information on the issuing authority or institution or the like. Rasterized markings are particularly suitable for laser marking, wherein the halftone dots can be generated in a simple manner by pulsed laser irradiation.

In a preferred embodiment, the metal layer is vapor-deposited or printed on one of the translucent cover layers. Alternatively, the metal layer can be vapor-deposited or printed on a transparent intermediate layer arranged between the translucent cover layers.

Suitably, one or preferably both of the translucent cover layers is provided with a protective layer, which is transparent at least in the region of the markings.

The invention also includes a data carrier, in particular a value document, such as a banknote, an identity card or the like, which is equipped with a security element of the type described above. The security element can be embedded in the interior of the data carrier and thus be part of the data carrier itself, or it can be subsequently applied to the surface of the data carrier, for example, glued. In the latter case, it is expedient if the data carrier is transparent or translucent in the area of the markings of the security element. The security element can also be arranged over an opening of the data carrier, for example a punched out hole of a banknote. It is also conceivable that the disk itself consists of two layers of paper with intermediate metal layer.

In addition to the described security element, the data carrier can be provided with one or more further security features, in particular with luminescent, magnetic or electrical substances, or with optically variable structures, such as holographic structures.

In a method for producing a security element of the type described above, according to the invention a metal layer with two translucent Cover layers combined so that it lies between the two cover layers, and then applied to the layer sequence with a laser beam to introduce labels in the form of patterns, letters, numbers and / or images in the metal layer. The markings are preferably introduced with pulsed laser radiation, in particular in the infrared spectral range. The wavelength of the laser radiation and the material of the translucent cover layers are expediently coordinated so that the laser radiation is strongly absorbed by the metal layer and substantially not absorbed by the translucent cover layers.

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 Aufsicht auf eine Ausweiskarte mit einem erfindungsgemäßen Sicherheitselement in schematischer Darstellung,

Fig. 2

eine Schnittdarstellung der Ausweiskarte von Fig. 1 entlang der Linie II-II, und

Fig. 3

eine Schnittdarstellung eines Sicherheitselements nach einem anderen Ausführungsbeispiel der Erfindung.

Show it:

Fig. 1

a plan view of an identity card with a security element according to the invention in a schematic representation,

Fig. 2

a sectional view of the ID card of Fig. 1 along the line II-II, and

Fig. 3

a sectional view of a security element according to another embodiment of the invention.

Fig. 1 shows a schematic representation of a plan view of an identity card 10, which contains a security element 12 according to the invention. In the embodiment the security element 12 is part of the card body 14 of the ID card 10.

Fig. 2 shows a cross section through the badge 10 in the region of the security element 12 along the line II-II of Fig.1 , In other embodiments, the security element may also be a separately manufactured element, which is applied to a data carrier, such as the card body 14, for example, glued.

The security element 12 contains a metal layer 20 into which markings 16, in the present case in the form of the letter sequence "AB", are introduced by means of a laser beam. In addition, the ID card contains 10 more personal or non-personal data 18, which may be applied to the card in any suitable method. Depending on the purpose of the badge 10, the data 16 and 18 include, for example, the name, date of birth, nationality or portrait of the holder, issuing authority or issuing institution, issue date, and the like.

As best in the sectional view of the Fig. 2 In addition to the metal layer 20, the security element 12 includes an upper and a lower translucent cover layer 26 and 28, which are each covered and protected by a transparent plastic film 30 or 32. The translucent cover layers 26 and 28 consist in the embodiment of white-colored polycarbonate films of a thickness of about 150 microns. While such films are often referred to as being opaque in other contexts, it is important in the present invention that the films are not completely opaque, but transmit some, albeit small, amount of light when illuminated from the back of the card. Corresponding they are referred to in this description as translucent, so translucent.

In order to insert the markings 16 into the identity card 10, the card is subjected to laser pulses of an infrared laser, for example a Nd; YAG laser with a wavelength of 1.064 μm. The plastic films 30 and 32 and the white polycarbonate films 26 and 28 have a negligible absorption for the infrared radiation and are not changed by the laser radiation. In contrast, the metal layer 20 absorbs the laser radiation so strongly that the deposited energy causes a local change of state in the metal layer. This change of state in the metal layer 20 may, for example, consist in a partial or complete local removal of the metal layer or in a local transformation of the metal layer into a transparent or translucent modification.

By a suitable choice of beam diameter and pulse energy, it is thus possible to introduce markings in the form of patterns, letters, numbers or images into the metal layer 20, which consist of areas 22 in which the metal layer has been changed and areas 24 in which the metal layer remains unchanged , consist.

Upon viewing the badge 10 in transmitted light, a positive representation of the indicia can be seen, where light can pass through the regions 22 to the viewer's eye and therefore appear bright, while the remaining metal layer in the regions 24 is that from the back of the card The incident light is completely blocked so that these areas appear dark.

In reflected light, the image impression of the markings is reversed. When viewed in incident light, the incident light is reflected more strongly in the metal layer regions 24 than in the translucent regions 22, so that then the metal layer regions 24 appear bright and the metal-free regions 22 appear comparatively dark. This change effect is analogous to the effects that occur with classical watermarks and is therefore also referred to in the present description as a watermark effect.

Another embodiment of a security element 40 according to the invention is shown in FIG Fig. 3 shown. The security element 40 has a transparent polycarbonate film 42 of a thickness of about 100 μm, onto which a thin metal layer 44, for example an aluminum, copper, gold layer, has been vapor-deposited. The coated polycarbonate film 42 is embedded between two translucent cover films 46 and 48, each consisting of a transparent polyester film 50 and 52 and printed layers 54 and 56 applied thereon. Over the cover sheets 46 and 48, further transparent polyester films 58 and 60 are arranged for protection.

The translucency of the coversheets 46 and 48 is achieved in this embodiment by the print layers 54 and 56 and can be adjusted as required by the degree of coverage of the ink and the thickness of the print layer in a wide range.

In addition, the inks are chosen so that the print layers are substantially transparent to the laser radiation used for marking. For personalization, the metal layer 44 of the security element 40 is provided with markings as described above, thereby producing a watermark effect in the data carrier equipped with the security element.

Claims (18)

1. A multilayer security element (12) having a metal layer into which are introduced, by a laser beam, identifiers in the form of patterns, letters, numbers and/or images, characterized in that the metal layer is disposed between two translucent coating layers, whose transmittance in the visible spectral range is less than 10%, causing the identifiers (16) in the metal layer (20) to display a watermark effect in which they appear, when viewed in transmitted light, as a positive image, and when viewed in reflected light, as a negative image.
2. The security element (12) according to claim 1, characterized in that the transmittance of the translucent coating layers in the visible spectral range is less than 5%.
3. The security element (12) according to claim 1 or 2, characterized in that the translucent coating layers are colored, especially appear white or pastel-colored in reflected light.
4. The security element (12) according to at least one of claims 1 to 3, characterized in that the introduction of the identifiers (16) occurs through material ablation in the metal layer (20).
5. The security element (12) according to at least one of claims 1 to 4, characterized in that the introduction of the identifiers (16) occurs through a local transformation of the metal into a transparent or translucent modification.
6. The security element (12) according to at least one of claims 1 to 5, characterized in that the translucent coating layers exhibit no appreciable absorption at the wavelength of the laser radiation used for labeling (16).
7. The security element (12) according to at least one of claims 1 to 6, characterized in that the identifiers (16) comprise personal data, such as a signature, a birth date, a portrait or the like.
8. The security element (12) according to at least one of claims 1 to 7, characterized in that the identifiers comprise data relating to the data carrier, such as a serial number, a validity period or the like.
9. The security element (12) according to at least one of claims 1 to 8, characterized in that the identifiers are present in screened form.
10. The security element (12) according to at least one of claims 1 to 9, characterized in that the metal layer (20) is vapor deposited or imprinted on one of the translucent coating layers.
11. The security element (12) according to at least one of claims 1 to 10, characterized in that the metal layer (20) is vapor deposited or imprinted on a transparent intermediate layer disposed between the translucent coating layers.
12. The security element (12) according to at least one of claims 1 to 11, characterized in that one or both of the translucent coating layers is provided with a protective layer that is transparent at least in the area of the identifiers (16).
13. A data carrier, especially a value document, such as a banknote, identification card or the like, having a security element (12) according to one of claims 1 to 12.
14. The data carrier according to claim 13, characterized in that the security element is embedded in the interior of the data carrier or applied to the surface of the data carrier.
15. The data carrier according to claim 13 to 14, characterized in that the data carrier is provided with one or more further security features, especially with luminescent, magnetic or electrical substances, or with optically variable structures, such as holographic structures.
16. A method for manufacturing a security element (12) according to at least one of claims 1 to 12, in which

    - a metal layer (20) is combined with two translucent coating layers, whose transmittance in the visible spectral range is less than 10%, such that it lies between the two coating layers, and

    - subsequently, the series of layers is impinged on with a laser beam to introduce into the metal layer identifiers (16) in the form of patterns, letters, numbers and/or images.
17. The method according to claim 16, characterized in that the identifiers (16) are introduced with pulsed laser radiation, especially in the infrared spectral range.
18. The method according to claim 16 or 17, characterized in that the wavelength of the laser radiation and the material of the translucent coating layers are coordinated with each other in such a way that the laser radiation is strongly absorbed by the metal layer (20) and substantially not absorbed by the translucent coating layers.

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