EP1687763A1

EP1687763A1 - Data carrier comprising markings

Info

Publication number: EP1687763A1
Application number: EP04818387A
Authority: EP
Inventors: Günter Endres; Georg Kruse; Josef Riedl
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient GmbH
Priority date: 2003-11-12
Filing date: 2004-11-08
Publication date: 2006-08-09
Also published as: EP1983473A1; ES2341391T3; US8409693B2; US20100290039A1; WO2005048182A1; US20070087173A1; EP1983473B1; DE502004010924D1; DE10353092A1; ATE461499T1

Abstract

Data carrier into which markings are introduced using a laser beam, said markings being visible as laser-generated irreversible changes of the optical characteristics of the data carrier. The data carrier comprises a laser-sensitive layer (20) that is opaque in the visible spectrum and is combined with a securing layer (22) that is metalized in at least a partial area. The markings (30, 32) are introduced simultaneously and with exactly matching registers in the laser sensitive layer and the metalized area (24) of the securing layer. An independent claim is made for a method for manufacturing an inventive data carrier.

Description

Data carriers with markings

The invention relates to a data carrier in which markings are introduced by means of a laser beam and which are visible in the form of irreversible changes in the optical properties of the data carrier caused by the laser beam. The invention further relates to a method for producing such a data carrier and a method for checking the integrity of such data carriers.

It is known to personalize identification cards, such as credit cards, bank cards or identity cards, by means of laser engraving. In the case of personalization by laser engraving, the optical properties of the card material are irreversibly changed in the form of a desired marking by suitable guidance of a laser beam.

For example, the identification card described in the document DE 29 07004 contains two cover foils and a card insert into which the personalization data are written with a laser beam through one of the two cover foils. In order to make it more difficult to reproduce such ID cards with modern copying machines, the personalization data are often placed in metallic layers against a dark background. Since the metallic background leads to a directed reflection of incident light rays and the detector in copiers is usually arranged in such a way that it can only detect the light diffusely scattered by the original, the metallic surfaces and the data entered appear black in the copy.

Despite the recognized high level of security of laser-personalized ID cards, there is a residual risk of falsification as a result of a separation of the front and back of the card and the possible manipulations of internal information such as text and picture objects. In particular, after separation of the card foils, an inner metal foil can be falsified or exchanged.

Proceeding from this, the object of the invention is to specify a data carrier of the type described at the outset with increased security against forgery. In addition, attempts at manipulation should be ascertainable using simple means and, if possible, also by laypersons.

This task is performed by the data carrier with the characteristics of

Main claim solved. A method for producing such a data carrier and a method for checking the integrity of such data carriers are specified in the independent claims. Developments of the invention are the subject of the dependent claims.

The data carrier according to the invention is based on the prior art in that it comprises a laser-sensitive layer which is opaque in the visible spectral range and which is combined with a security layer metallized in at least one partial area. The markings are inserted into the laser-sensitive layer and the metallized partial area of the security layer at the same time and in a register-accurate manner. The integrity of the data carrier can thus be checked at any time by checking the registration accuracy of the labels. All you need is a bright flashlight or just looking at the data carrier against the search.

The introduction of the markings into the security layer can advantageously be carried out, for example, by removing material in the metallized partial area or via a local conversion of the metal into a transparent or translucent modification.

In expedient configurations, one or more intermediate layers are arranged between the laser-sensitive layer and the security layer. The intermediate layers are preferably transparent and can also be colored and / or printed. They can also have fluorescent properties. In particular if the intermediate layers are not completely transparent, they advantageously have one or more cutouts in the area of the markings in order to expose the view of the markings and to use the opaque background as a contrast element.

The metallized partial area can advantageously be vapor-deposited on the securing layer or formed by a printing layer of a metallic effect paint. The metallized partial area can also have a diffraction pattern, in particular a hologram structure, so that an additional angle-dependent image impression is created for the viewer.

The laser-sensitive layer is preferably formed by a plastic film doped in at least one partial area. In other, likewise advantageous configurations, the laser-sensitive layer is formed by a plastic film, which is provided at least in a partial area with a printing layer that absorbs the laser radiation. The plastic film can then be transparent, since the opacity required for the contrast effect is provided by the printing layer. The plastic film can furthermore be provided with fluorescent properties, for example by incorporating fluorescent pigments during film production. In both variants, the plastic film can be made of poly carbonate or polyester. The use of paper as a laser-sensitive layer is also conceivable. Paper made from cotton fibers is preferably used. The laser-sensitive layer can also be a metal layer. The metallized partial area and the laser-sensitive layer are then preferably formed from metals of different colors.

While so far only a single, laser-sensitive layer that is opaque in the visible spectral range has been described, it is also possible according to the invention to provide several such layers in the data carrier. The different laser-sensitive layers can then be provided with different types of markings or combined with different metal layers.

The markings inserted into the data carrier can contain any pattern or characters. Labels that include a halftone pattern reproduced from an original, in particular an image, such as a portrait, are particularly well suited, since the human eye can perceive even the smallest deviations in the congruence. The halftone pattern is preferably introduced using halftone technology, with different brightness levels of the halftone pattern being generated in particular by a different halftone dot density, a different halftone dot size and / or by a different halftone dot blackening.

In an advantageous further development of the invention, the metallized partial area together with the opaque layer shows a tilting effect in the incident light, in which the image impression of the introduced markings tilts from a positive representation into a negative representation when the viewing angle changes. As explained in detail below, this contrast reversal is caused by the interaction of the directionally reflective metallic Sub-areas and the diffuse scattering labeling areas explained. This effect can also be used as copy protection.

Instead of a single metallized security layer, several security layers of this type can also be provided. For example, the combination of metallized security layers in different levels can achieve a spatial effect. The metallized security layers can additionally be provided with a laser tilt pattern structure, as described, for example, in the publication EP 0219012 A2.

For protection, the laser-sensitive layer and / or the security layer can be covered with further layers that are transparent at least in the area of the markings, so that the laser-sensitive layer or the security layer, preferably both layers, are arranged in the interior of the data carrier.

The data carrier preferably represents an identification card, such as a credit card, bank card, cash payment card, authorization card, an identity card or a passport personalization page. The data carrier can also represent a transfer element arranged on a carrier layer for application to an identification card or the like.

To produce a data carrier as described, the laser-sensitive layer, which is opaque in the visible spectral range, is combined with the at least one sub-area of the metallized security layer and possibly further layers, and the layer structure for introducing the markings is exposed to laser radiation from the side of the laser-sensitive layer, which means that the markings are carried out simultaneously and precisely in the laser-sensitive layer and the metallized section of the see- be introduced. The laser beam preferably strikes the layer structure perpendicularly. However, any other angle of incidence of the laser radiation on the layer structure is also conceivable. If the laser beam is irradiated at a certain angle, eg 70 °, to the surface of the card, the congruence of the engraved markings in principle remains in the different levels of the layer structure. The congruence must then of course be checked at the angle at which the marking was engraved in the layer structure using a laser.

The markings are preferably introduced with pulsed laser radiation, preferably with a wavelength in the infrared or visible spectral range. A halftone pattern reproduced from an original is advantageously used as a marking in raster technology, with different brightness levels of the halftone pattern being generated in particular by a different halftone dot density, a different halftone dot size and / or by different halftone dot blackening. The screen dot density is expediently chosen between 50 and 500 dpi (dots per inch), preferably between 150 and 250 dpi, particularly preferably between 170 and 200 dpi.

To check the integrity of a data carrier of the type described, the data carrier is illuminated with a strong light source, the registration accuracy of the markings in the opaque, laser-sensitive layer and the metallized partial area of the data link layer is determined, and the integrity of the data carrier is assessed on the basis of the determined registration accuracy. Overall, the invention provides a significant increase in the security of personalized data carriers, while at the same time the security can be checked easily. Without significant influence on the throughput performance, three pieces of information can be included in the card material to protect against corruption in one work step, for example when producing cards:

1) a photo, for example on the front of the card,

2) a transmitted light effect which, depending on the type of personalization, provides a positive or negative image, and

3) a personalization of a metallized film layer, opposite and absolutely congruent with the photo on the front of the card.

Further exemplary embodiments and advantages of the invention are explained below with reference to the figures. For the sake of clarity, the figures are drawn to a representation true to scale and proportion.

Show it:

1 shows a schematic representation of the front view of an identification card according to an exemplary embodiment of the invention,

2 shows the rear view of the identity card of FIG. 1, 3 is a sectional view of the identification card of FIG. 1 along the line 111-111,

4 to 7 are sectional views of further identification cards according to exemplary embodiments of the invention.

1 and 2 show the front and rear view of an identification card 10 according to the invention in a schematic representation. The identification card 10 contains a portrait 12 of the card holder and further personal data 14, in the exemplary embodiment the first and last name of the holder. In addition, the identification card can contain further personal or non-personal data 16, such as date of birth, nationality, issuing authority, date of issue and the like. The portrait 12 and the name 14 of the identity card 10 are for illustration purposes only and do not correspond to a real person.

While the front side 26 of the identity card 10 shows the portrait of the cardholder as a halftone image 12, part of the portrait is visible in a metal foil 18 from the back of the card 28. Due to their simultaneous and register-accurate generation described below, the halftone portrait 12 and the portrait inscribed in the metal foil 18 are arranged in a completely identical manner in the case of an intact identification card 10.

This congruence can be checked with simple aids, for example with a strong flashlight or by looking at the ID card against daylight. In the event of a manipulation attempt by separating the card foils and exchanging or falsifying the inner metal foil 18, the two are congruent Portraits are destroyed and can then no longer be restored to their original accuracy. The personalization of the front of the card and the metal foil on the inside is thus effectively and easily verified.

The layer structure of the identity card 10 and its production will now be explained with reference to the simplified schematic representation of FIG. 3. In the simplest case, the identification card 10 consists of a core layer 20, which is opaque in the visible spectral range, and a transparent film 22, onto which a metal layer 24, for example an aluminum, copper or gold layer, is evaporated in a partial area.

For personalization, the identification card 10 is exposed to pulsed, infrared laser radiation from the front side 26 of the card. For this purpose, the core layer 20 is doped with additives which are capable of absorbing the infrared laser radiation and causing a local blackening 30 of the core layer 20. The additives are, for example, fillers. Depending on the type of filler and / or filler content, the absorption of the laser light and thus the degree of blackening can be controlled. The pulse energy of the laser radiation is selected such that it reaches through the core layer 20 and is absorbed in the metal layer 24. Due to the influence of the laser radiation, the optical properties of the thin metal layer 24 in the detected modification areas 32 are changed locally in such a way that the portrait inscribed from the front is visible mirror-inverted when viewed from the back of the card 28. The change in state of the metal layer 24 can consist, for example, of partial or complete local removal of the metal layer or a local transformation of the metal layer into a transparent or translucent modification. In the exemplary embodiment, an Nd: Y AG laser with a wavelength of 1.064 μm, a beam diameter of approximately 60 μm and a pulse energy of up to 2 J / cm ^{2 was} used to introduce the markings. Other infrared lasers, such as Nd: glass lasers or the longer-wave C0 ₂ lasers, are also suitable for personalization. It goes without saying that the laser parameters used in each case, such as beam diameter and pulse energy, are matched to the number and the thickness of the layers to be engraved.

By traversing the image area of the portrait 12 in a fixed grid and a pulse-to-pulse variation of the laser power corresponding to the respective degree of blackening, a halftone image, such as the portrait 12, can be generated without problems with a resolution of, for example, 200 dpi.

Through a suitable choice of the background of the metal layer 24, a tilting effect can be achieved when viewed from the back of the card 28. Here, the image impression in reflected light tilts from a positive representation to a negative representation regardless of the tilt axis when the viewing angle changes. Without being bound to any particular explanation, the contrast reversal is explained by the fact that light incident from the rear is reflected by the unmodified areas of the metal layer 24, while diffusely scattering in the removed or modified areas 32. If the viewer is at the solid angle of the directed reflection, the metal layer 24 appears brighter than the modified areas 32, while from other viewing angles the diffusely reflecting areas 32 remain bright, but the metal layer areas appear dark. This effect is particularly clear when the metal layer 24 is arranged in front of a light, for example white or pastel colored background. FIG. 4 shows a further exemplary embodiment of an identification card 40 according to the invention with a more complex layer structure. The layer sequence of the identification card 40 comprises a transparent, low-doped film 42, a transparent undoped film 44, a transparent, highly doped film 46, an opaque film 48, a transparent undoped film 50 and a transparent, low-doped film 52. In the exemplary embodiment, all of the films mentioned are polycarbonate films , The films may have fluorescent properties.

A metal layer 54, here an aluminum layer, with a thickness of a few tenths of a μm was evaporated onto the transparent undoped film 50 before the films were joined together. The foils were then laminated and the card thus formed was personalized by laser engraving as described above. In the doped foils 42 and 46, local blackening 56 was produced by the absorption of the laser radiation. At the same time, the laser properties in the modification regions 58 irreversibly changed the optical properties of the metal layer 54 locally and congruently with the blackening 56. Further markings can be written into the doped film 52 from the back of the identity card 40.

The exemplary embodiment of FIG. 5 is shown in an exploded view for the sake of a clear representation, in which the individual layers have not yet been joined and in which the personalization of the identification card 60 has not yet taken place. The layer structure of the identification card 60 comprises a transparent, low-doped film 62, a printed transparent film 64, which can be undoped or low-doped, a highly-doped transparent film 68, which is provided with a thin metal layer 76, a printed, highly-doped transparent film 70 and one low-doped transparent film 74. Also in this embodiment, the films mentioned are polycarbo- natfolien. The films can also be provided with fluorescent properties if necessary.

The foils 64 and 70 are each provided with a printing layer 66 or 72, the printing layer 72 having cutouts 80 in the area of the metal layer 76 or at least in the area of the markings introduced in order to expose the view of the markings. In this exemplary embodiment, the opacity of the card body is not achieved by an opaque film, but rather by the print layers 66 and 72, which are opaque at least in some areas. In particular, the print layer 66 is opaque in the area of the metal layer 76. The printing layers 66 and / or 72 can also be applied with effect colors, such as, for example, fluorescent colors or colors containing optically variable pigments.

In the exemplary embodiment, the metal layer 76 is formed by a hologram patch with a diffraction pattern 78 which, in addition to the portrait described above, provides the viewer with an angle-dependent image impression in a manner known per se. For example, the hologram patch can contain an angle-dependent play of colors or an image motif that moves or changes when tilted. Such a hologram patch can of course be used in all the described embodiments instead of a simple metal layer.

6 shows a further exemplary embodiment of an identification card according to the invention. The layer sequence of the card comprises a transparent film 90 which has been printed over the entire area with a fluorescent print 91. Above is a metallic layer, preferably silver or gold 92. This is covered with a transparent film 93, on which in turn a metallic layer 94, which is preferably silver or is gold colored. The metal layers 94 and 92 preferably have a different metallic appearance, so that the card, viewed from the top and bottom, has a different appearance. This card structure is now exposed to laser radiation from the layer 94, so that the marking 100 is generated in the layers 92 and 94. In this case, the marking is metal removal, so that recesses are created in the metal layer. By illuminating the card with UV radiation from the side of the layer 90, a viewer who looks at the card from the side of the coating 94 can see fluorescent spots in the area of the recess 100. The recesses 100, which appear fluorescent to the viewer when appropriately illuminated, can be pictorial representations, but also encodings.

7 shows a further exemplary embodiment according to the invention. The layers 95 are metallic layers that have been evaporated onto a transparent film 97. The layers 96 are also metallic layers that have been vapor-deposited on the side opposite the metallic layer 95. These two layer structures were each laminated on one side of a film 98 doped with a fluorescent pigment. When this structure is exposed to laser radiation, the markings 101 are generated in the metal layer. By removing the corresponding metal layer at the locations 101, the viewer can again recognize fluorescent markings at the locations 101 when appropriately illuminated with excitation radiation.

Claims

Patent claims

1.Data carrier into which markings are introduced by means of a laser beam, which are visible in the form of irreversible changes in the optical properties of the data carrier caused by the laser beam, characterized in that the data carrier comprises a laser-sensitive layer which is opaque in the visible spectral range and which has a is combined at least in a partial area of the metallized security layer, the markings being introduced by the laser beam simultaneously and in register with the laser-sensitive layer and the metallized partial area of the security layer.

2. Data carrier according to claim 1, characterized in that the introduction of the markings into the security layer takes place via material removal in the metallized partial area.

3. Data carrier according to claim 1, characterized in that the labeling is introduced into the data link layer via a local conversion of the metal into a transparent or translucent modification.

4. Data carrier according to at least one of claims 1 to 3, characterized in that one or more intermediate layers are arranged between the laser-sensitive layer and the security layer.

5. A data carrier according to claim 4, characterized in that the intermediate layer (s) are colored and / or printed and / or fluoresce.

6. Data carrier according to claim 4 or 5, characterized in that the intermediate layer (s) in the area of the markings have one or more cutouts.

7. Data carrier according to at least one of claims 1 to 6, characterized in that the metallized sub-area is vapor-deposited on the security layer.

8. A data carrier according to at least one of claims 1 to 6, characterized in that the metallized partial area is formed by a printing layer of a metallic effect color.

9. Data carrier according to at least one of claims 1 to 8, characterized in that the metallized partial area has a diffraction pattern, in particular a hologram structure.

10. A data carrier according to at least one of claims 1 to 9, characterized in that the laser-sensitive layer is formed by a plastic film doped in at least one partial area.

11. Data carrier according to at least one of claims 1 to 9, characterized in that the laser-sensitive layer is formed by a plastic film which is provided at least in a partial area with a printing layer absorbing the laser radiation.

12. Data carrier according to at least one of claims 1 to 11, characterized in that several opaque, laser-sensitive layers are provided in the visible spectral range.

13. Data carrier according to at least one of claims 1 to 12, characterized in that the markings comprise a halftone pattern reproduced from an original, in particular an image, such as a portrait.

14. A data carrier according to claim 13, characterized in that the halftone pattern is introduced using halftone technology, wherein different brightness levels of the halftone pattern are generated in particular by a different halftone dot density, a different halftone dot size and / or by a different halftone dot blackening.

15. Data carrier according to at least one of claims 1 to 14, characterized in that the metallized partial area together with the opaque layer shows a tilting effect in reflected light, in which the image impression of the markings tipped over from a positive representation to a negative representation when the viewing angle changes.

16. A data carrier according to at least one of claims 1 to 15, characterized in that a plurality of metallized security layers are provided at least in a partial area, preferably that a spatial effect is achieved by combining metallized security layers in different planes.

17. A data carrier according to at least one of claims 1 to 16, characterized in that the or one of the metallized security layers is additionally provided with a laser tilt image structure.

18. Data carrier according to at least one of claims 1 to 17, characterized in that the laser-sensitive layer and / or the security layer are covered with further layers, at least in the area of the markings, so that the laser-sensitive layer or the security layer, preferably both layers, are arranged in the interior of the data carrier.

19. Data carrier according to at least one of claims 1 to 18, characterized in that the data carrier represents an identification card, such as a credit card, bank card, cash payment card, authorization card, an identity card or a passport personalization page.

20. Data carrier according to at least one of claims 1 to 18, characterized in that the data carrier represents a transfer element arranged on a carrier layer for application to an identification card or the like.

21. A method for producing a data carrier according to at least one of claims 1 to 20, in which the opaque, laser-sensitive layer in the visible spectral range is combined with the at least in a partial area metallized security layer and optionally further layers, and the layer structure for introducing the labels from the Laser radiation is applied to the side of the laser-sensitive layer, as a result of which the markings are introduced into the laser-sensitive layer and the metallized partial area of the security layer simultaneously and in register.

22. The method according to claim 21, characterized in that the markings with pulsed laser radiation, preferably with a wavelength in the infrared spectral range, are introduced.

23. The method according to claim 21 or 22, characterized in that a halftone pattern reproduced from an original is introduced as a marking using raster technology, different brightness levels of the halftone pattern being generated in particular by a different halftone dot density, a different halftone dot size and / or by a different halftone dot blackening and where the screen dot density is between 50 and 500 dpi, preferably between 150 and 250 dpi, particularly preferably between 170 and 200 dpi.

24. The method for checking the integrity of a data carrier according to at least one of claims 1 to 20, in which the data carrier is illuminated with a strong light source, the registration accuracy of the markings in the opaque, laser-sensitive layer and the metallized partial region of the data link layer is determined and on the basis the integrity of the data carrier is assessed based on the particular register accuracy.