EP1618006B1 - Security element and verification method for a value document - Google Patents

Abstract

The invention relates to a security element for a value document, such as a banknote, a passport, an identity card or similar, comprising a low-coercive magnetic region (24) for forming a magnetic code. According to the invention, said element also comprises a high-coercive magnetic region (22) that at least partially overlaps the low-coercive magnetic region (24) and magnetises the latter (24) when in the magnetised state.

Description

The invention relates to a security element for a value document, such as a banknote, a passport, a passport document or the like, having a low-coercive magnetic region for forming a magnetic code. The invention further relates to a value document having such a security element, to a method for producing such a security element and to a method for checking a value document provided with such a security element.

Banknotes and other monetary securities, such as stocks, checks, traveler's checks, check or credit cards, or other forgery-prone securities, such as passports and other identity cards, often incorporate a security element to increase counterfeit security. The security element can be, for example, a security thread embedded in a banknote, an applied security strip or a self-supporting element, such as a transfer element, a patch or a label, which after its manufacture is firmly connected to the object to be secured.

It is also known to provide the security elements to further increase the security against counterfeiting with a magnetic material. For example, from the document DE-OS 1696 245 a safety device in the form of a thread or a band is known, which is provided with an interrupted ferromagnetic coating. By scanning the thread or tape in a testing device, the authenticity of a document provided with the security device can be checked.

A security document with an introduced magnetic security element is known from DE 4101301. The security element has a magnetic coating with light gray to silvery soft magnetic pigments, which are mixed with a varnish and spread with this on a substrate. The magnetic security element hardly appears after being embedded in a security document in incident light.

In order to further increase the security against counterfeiting, EP 748 896 A1 proposes to provide a security document for automatic authentication with a magnetic material whose coercivity is between 10 and 250 Oe (800 A / m to 20 kA / m). While the remanence of the material corresponds to the commonly used magnetic materials and thus can be measured with standard sensors, the low coercivity of the magnetic material can only be determined with special sensors. As a result, an additional securing effect is achieved, which greatly complicates the adjustment of the magnetic security element.

The document DE 40 22 739 A1 discloses a test device for documents equipped with magnetic properties, with the magnetic particles low remanence can still be detected with high reliability.

However, the currently used magnetic security elements are not intelligent, so that a set or introduced magnetic property is fixed for all times. Subsequently, only the presence or absence of the magnetic properties is checked. In order to be able to store information, microchips are increasingly being integrated into all types of value documents. The equipment of value documents with microchips is, however, with not inconsiderable manufacturing costs and with additional costs. Also, not all types of value documents are equally suitable for the equipment with microchips.

Proceeding from this, the object of the invention is to provide a security element which avoids the disadvantages of the prior art. In particular, the security element should be activated by switching on and off or information on and off can save and thereby be easy and inexpensive to produce.

This object is achieved by the security element having the features of the main claim. A value document with such a security element, a production method for such a security element and a method for checking a value document provided with such a security element are the subject matter of the independent claims. Further developments of the invention are the subject of the dependent claims.

According to the invention, a high-coercive magnetic region is provided in a security element of the type mentioned, which at least partially overlaps the low-coercive magnetic region and, in the magnetized state, magnetizes the low-coercive magnetic region, preferably brings it to saturation. By this measure, the magnetism in the low-coercive magnetic field of the security element can be switched on and off in a simple manner.

If the high-coercive magnetic region is demagnetized, a magnetic code can be written by magnetizing the low-coercive magnetic region or partial regions thereof in a manner known per se. Subsequently, the magnetization of the low-coercive magnetic field be detected by a conventional sensor, such as in a banknote processing machine.

When the high-coercive magnetic field is magnetized, its magnetic field magnetizes or even saturates the low-coercive magnetic region. An external magnetic field of the order of magnitude of the coercive field strength of the low-coercive magnetic region can then no longer magnetize it, the magnetic code is thus switched off. To turn on the magnetic code, the overlapping high-coercive magnetic region is demagnetized again. Subsequently, the low-coercive magnetic region can again be detected by means of conventional sensors.

According to a preferred embodiment of the security element according to the invention, the low-coercive magnetic region contains a plurality of separately magnetizable partial regions. These subareas together advantageously form a magnetic code. A multiplicity of arbitrary, complex types of magnetic codes can be produced in that the subregions have a specific geometry and / or spatial arrangement and / or coercivity and / or remanence. The magnetic properties coercivity and remanence can be controlled by the type, amount or layer thickness of the magnetic material in the individual subregions. The easiest way, however, is to construct the magnetic code from individual magnetic bits which are formed by the presence or absence of magnetization in a partial region of the low-coercive magnetic region.

The high-coercive magnetic region may be formed continuously, or may in turn comprise a plurality of separate subregions, each of which at least partially overlap one or more of the low-coercive subregions. In particular, in each case a high-coercive partial area can be assigned to a low-coercive partial area and overlap it. By magnetizing one of the high-coercive partial regions, information stored in the associated low-coercive magnetic region, such as a magnetic bit, can then be switched off in a targeted manner.

In a preferred embodiment, the high-coercive magnetic region completely overlaps the low-coercive magnetic region. However, it is also within the scope of the invention if the high-coercive magnetic region is formed slightly smaller than the low-coercive magnetic region, as long as it is ensured that magnetization of the high-coercive magnetic region magnetizes or saturates the low-coercive magnetic region.

The low-coercive magnetic region expediently has a coercive field strength between about 10 and about 500 Oe (800 A / m to 40 kA / m), preferably between about 150 and about 350 Oe (12 kA / m to 28 kA / m). Advantageously, the low-coercive magnetic region is formed in a material layer containing iron oxides, pure iron, nickel or another soft magnetic material. The thickness of the material layer is preferably between about 0.05 μm and about 20 μm.

The high-coercive magnetic region expediently has a coercive field strength above about 300 Oe (24 kA / m), preferably above about 1000 Oe (80 kA / m) and particularly preferably above about 2000 Oe (160 kA / m). Layers having a coercive force of up to about 4000 Oe (320 kA / m) are industrially readily available, with such high field strengths being quite advantageous in order to increase security against unwanted extinguishment or magnetic reversal. With special, but more expensive Materials achieve coercivities of over 35,000 Oe (2.8 MA / m). These special materials can be used with advantage for the high-coercive magnetic field. The thickness of the high coercive material layer is preferably between about 0.05 μm and about 20 μm. The high-coercive material preferably contains an alloy of iron / cobalt / nickel or iron / cobalt / vanadium or platinum / cobalt or aluminum / nickel / cobalt or iron / cobalt / chromium or samarium / cobalt or samarium / copper or samarium / iron or samarium / Zirconium or neodymium / iron or neodymium / boron.

According to a preferred embodiment, the low-coercive and the high-coercive magnetic region are arranged one above the other on a common carrier. In this case, both the low-coercive magnetic region can be arranged on the high-coercive magnetic region, and the high-coercive magnetic region lie above the low-coercive magnetic region.

Alternatively, the low-coercive and high-coercive magnet regions may be disposed on opposite sides of a common carrier. It is only important that the distance of the two magnetic regions is small enough to obtain the saturation effect of the high-coercive region.

In addition to the mentioned magnetic regions, a further high-coercive magnetic region may be provided which serves to store a switching state of the security element. This switching state can be read and evaluated, for example, with a magnetic sensor. In cases where no complex magnetic code is required, even this high-coercive magnetic field is sufficient to secure an object.

According to an advantageous development of the security element according to the invention, an opaque cover layer is provided which opacifies the position and arrangement of the low-coercive magnetic region, in particular in transmitted light, at least in some areas.

The covering layer can be formed, for example, by an opaque black or colored printing ink or comprise a layer of aluminum, gold, copper, iron, nickel or an alloy of these metals. The cover layer may additionally have recesses in the form of characters or patterns which form visually and / or machine-readable information. The covering layer is applied to the upper of the magnetic layers, for example, or a separate covering layer is provided above and below the magnetic layers.

The security element preferably forms a security thread, a security strip or a transfer element. The transfer element is in particular arranged on a transfer film and is only detached from it for application to a value document.

In the production of a described security element, the low-coercive and the high-coercive magnetic region are preferably applied to a common substrate or to a security paper or security document, e.g. imprinted or evaporated by a vacuum vapor process.

The invention also includes a security paper and a value document such as a banknote, a passport, a passport document or the like provided with a security element of the type described. In particular, the security element can be contained on a carrier in the security paper or document of value. Alternatively, the low coercive and the high-coercive magnetic region of the security element can be arranged directly on the security paper or document of value. Both an arrangement on the same side and an arrangement on opposite sides of the security paper or value document come into consideration.

In addition to the magnetic areas mentioned, a further high-coherence magnetic area for storing a switching state of the security paper or value document can be provided in the security paper or value document, which is read and evaluated, for example, with a magnetic sensor.

• a) der niederkoerzitive Magnetbereich des Sicherheitselements oder Teilbereiche davon aufmagnetisiert,
• b) der hochkoerzitive Magnetbereich des Sicherheitselements aufmagnetisiert, falls das Wertdokument mit einer Markierung versehen werden soll,
• c) die remanente Magnetisierung des niederkoerzitiven Magnetbereichs oder der Teilbereiche davon bestimmt, und
• d) auf Grundlage der bestimmten remanenten Magnetisierung festgestellt, ob das Wertdokument mit einer Markierung versehen ist oder nicht.

For checking and optionally marking a security paper or value document described above is according to the invention

• a) magnetizing the low-coercive magnetic region of the security element or partial regions thereof,
• b) magnetizing the high-coercive magnetic region of the security element if the value document is to be provided with a marking,
• c) determines the remanent magnetization of the low-coercive magnetic field or the portions thereof, and
• d) determined on the basis of the determined remanent magnetization, whether the value document is marked or not.

Preferably, in step a) the low-coercive magnetic field is magnetized in a field which is at least twice as high as its coercive force.

In a preferred variant of the method, the high-coercive magnet region is magnetized in step b) perpendicular to a predetermined direction of magnetization of the low-coercive magnet region. The high-coercive magnetic field then magnetizes or saturates the sub-regions of the low-coercive magnetic region, so that a magnetic code can no longer be detected by a detection device such as a banknote sensor.

Alternatively, the high-coercive magnetic region may be magnetized in step b) in parallel to a predetermined magnetization direction of the low-coercive magnetic region. Also in this case, the field of the high-coercive magnetic field magnetizes or brings into saturation the partial regions of the low-coercive magnetic region. Due to the parallel alignment of the two magnetizations, a sensor designed for the low-coercive magnet regions always responds in this case, so that encoded information is superimposed on the magnetized high-coercive region and thus no longer recognized. In both variants mentioned, the magnetic code of the low-coercive magnetic regions is thus switched off.

In order to switch the magnetic code back on, the high-coercive magnetic region is expediently demagnetized after the value document has been marked. Thereafter, the magnetic code in the low-coercive magnetic regions of the security element can be magnetized and detected again in the detection in the desired direction. The low-coercive magnet code Therefore, it can be reactivated by demagnetization of the high-coercive area.

In a particularly preferred embodiment, the security contains an elongate security element with a longitudinal axis. The low-coercive portions are then magnetized in a direction perpendicular to the longitudinal axis.

If a later readout attempt fails according to step c), that is, if the specified magnetic code can not be read out successfully, it is concluded that a marking or a counterfeit is present.

If a marking of the value document is determined, the functionality of the value document is modified, in particular restricted, according to a preferred variant of the method. For example, an evaluation system can be set so that a marked banknote is only limitedly suitable for automating. Alternatively, it may be set so that also marked banknotes are fully automatic, but the evaluation system recognizes the banknote as marked and issues a corresponding indication.

Further embodiments and advantages of the invention are explained below with reference to the figures. For better clarity, a scale and proportioned representation is omitted in the figures.

Fig.1

eine schematische Darstellung einer Banknote mit eingebettetem Sicherheitsfaden und aufgeklebtem Transferelement, jeweils nach einem Ausführungsbeispiel der Erfindung,

Fig. 2

den Schichtaufbau des Sicherheitsfadens von Fig.1 im Querschnitt,

Fig. 3

eine Aufsicht auf den Sicherheitsfaden von Fig. 2 mit niederkoerzitiven Magnetbereichen als Magnetcode,

Fig. 4

eine Aufsicht auf den Sicherheitsfaden von Fig. 2 mit ausgeschaltetem Magnetcode in einem ersten markierten Zustand,

Fig. 5

eine Aufsicht auf den Sicherheitsfaden von Fig. 2 mit ausgeschaltetem Magnetcode in einem zweiten markierten Zustand, und

Fig. 6 bis 8

den Schichtaufbau von Sicherheitsfäden nach weiteren Ausführungsbeispielen der Erfindung im Querschnitt.

Show it:

Fig.1

a schematic representation of a banknote with embedded security thread and glued transfer element, each according to an embodiment of the invention,

Fig. 2

the layer structure of the security thread of Figure 1 in cross section,

Fig. 3

2 shows a plan view of the security thread of FIG. 2 with magnetically low-coercive magnet regions as magnet code,

Fig. 4

2 is a plan view of the security thread of FIG. 2 with the magnetic code switched off in a first marked state,

Fig. 5

a plan view of the security thread of Figure 2 with the magnetic code switched off in a second marked state, and

Fig. 6 to 8

the layer structure of security threads according to further embodiments of the invention in cross section.

1 shows a schematic representation of a banknote 10 with an embedded security thread 12 and a glued transfer element 14. As indicated by the dashed border, the security thread 12 is completely embedded in the interior of the banknote 10. The transfer element 14 is adhered to the surface of the banknote 10 with a hot melt adhesive. The security elements 12, 14 can, in addition to the magnetic structure described below, contain further security features, such as a negative text, a hologram or other optical effect structures, contain, which are known per se, and therefore will not be explained here.

The construction and the design of a security element according to the invention are explained in more detail below using the security thread 12 as an example. The transfer element 14 or other embodiments of inventive security elements can be designed analogously.

Figure 2 shows schematically the layer structure of the security thread 12 of Figure 1 in cross section. The security thread 12 has a transparent plastic film 20 serving as a substrate for the magnetic layers. Onto this plastic film 20 is printed a continuous high-coercive magnetic layer 22 having a coercive force greater than 2000 Oe. On the high coercive magnetic layer 22 is a plurality of low-coercive magnetic regions, here individual magnetic bits 24, printed, which form a magnetic code. For the sake of clarity, only three of the magnetic bits 24 are shown in the illustration of FIG. In the exemplary embodiment, the material and the production method of the low-coercive magnetic regions are coordinated with one another such that the low-coercive material layer has a coercive field strength of approximately 250 Oe.

The use of the security thread of Fig. 2 for checking a banknote will now be described in more detail with reference to Figures 3 to 5, each showing a plan view of the security thread of Fig. 2 in different magnetization states.

First, FIG. 3 shows the security thread 12 when the banknote 10 is active. In this state, the high-coercive magnetic layer 22 is demagnetized and thus exerts no influence on the low-coercive magnetic bits 24. The Magnetic bits 24 are magnetized in a known manner perpendicular to the longitudinal axis 26 of the security thread 12 to store a magnetic code in the security thread. In the embodiment of FIG. 3, the three magnetic bits 24 shown represent the binary number "101", which results from the sequence of magnetizations M ₀ (magnetized-demagnetized-magnetized). This magnetic code can be read out with a conventional banknote sensor and further processed.

To mark the banknote 10, for example for the magnetic marking of ransom, the high-coercive magnetic layer 22 is magnetized by a strong external magnetic field. The field of the highly coercive magnetic layer 22 magnetizes or saturates the magnetic bits 24 arranged above it so that subsequently the previously stored magnetic code with a banknote sensor can no longer be detected.

FIG. 4 shows a first marked state of the banknote 10, in which the high-coercive magnetic layer 22 is magnetized parallel to the longitudinal axis 26 of the security strip, as indicated by the thick arrows M ₁ . The magnetic bits 24 are also magnetized in this state until their saturation magnetization along the longitudinal axis 26. The remanent magnetization M _{1 of} the high-coercive layer keeps the saturation magnetization of the magnetic bits 24 stable. In this marked state, an external magnetic field of the order of magnitude of the coercive force of the magnetic bits 24 can not change their magnetization. The magnetic bits 24 are thus turned off, the bill is inactive.

A second marked state of the banknote 10 is shown in FIG. There, the high-coercive magnetic layer 22 is magnetized perpendicular to the longitudinal axis 26 of the security strip 12. The magnetization M _{2 of} the high-coercive Magnetic layer 22 brings here also the magnetic bits 24 in saturation. During a read operation, a magnetic sensor will respond over the entire length of the security strip 12. A stored information can thus no longer be taken from the magnetized magnet bits 24, the banknote is inactive as in the first marked state.

The type of marking and thus the switching state of the banknote can additionally be encoded in another high-coercive magnetic area 16 (FIG. 1) on the banknote. In the magnetization of the high coercive magnetic layer 22, the magnetic region 16 is also magnetized, so that its magnetization direction corresponds to that of the magnetic layer 22. The switching state of the banknote (unmarked, first or second marked state) can be interrogated in this embodiment via a magnetic sensor from the magnetic region 16. It is also possible to check only one direction of magnetization. The direction of magnetization perpendicular thereto and the demagnetized state then represent a common switching state. It is also possible to provide a document only with the high-coercive magnetic region 16.

6 to 8 show the layer structure of security threads according to further embodiments of the invention in cross section. In the embodiment of FIG. 6, each low-coercive magnetic bit 34 is assigned its own high-coherence magnetic region 32. The magnetic bits 34 may then be individually turned on or off by magnetizing the associated magnetic regions 32. Accordingly, a plurality of groups of magnetic bits may be formed which are turned on or off together by a high-coercive magnetic domain.

FIG. 7 shows a security thread as in FIG. 2, in which the sequence of the highly coercive and low-coercive magnetic layers 42, 44 on the substrate 40 is interchanged.

As shown in FIG. 8, the high-coercive and low-coercive magnetic layers 52, 54 may be disposed on different sides of the common substrate 50. In this case, only the coercive strengths of the magnetic layers 52, 54 and the layer thickness of the substrate 50 must be coordinated so that a magnetization of the high coercive magnetic layer 52 drives the magnetic bits 54 into saturation. The substrate 50 may in this case also be formed by the security itself, for example the banknote 10.

It is also conceivable, two substrates, wherein the low-coercive areas and the hochkoerzitiven areas are each on a substrate to laminate together in a suitable manner.

Claims (32)

1. A security element for a document of value, such as a bank note, a passport, an identification document or the like, with a low-coercive magnetic area (24; 34; 44; 54), characterized in that a high-coercive magnetic area (22; 32; 42; 52) is provided, which overlaps the low-coercive magnetic area (24; 34; 44; 54) at least partially and in a magnetized state magnetizes the low-coercive magnetic area (24; 34; 44; 54).
2. The security element according to claim 1, characterized in that the low-coercive magnetic area contains a plurality of separately magnetizable partial areas (24; 34; 44; 54).
3. The security element according to claim 2, characterized in that the separately magnetizable partial areas (24; 34; 44; 54) form individual bits for storing a magnetic code.
4. The security element according to claim 2 or 3, characterized in that the high-coercive magnetic area comprises a plurality of separate partial areas (32), which each overlap at least partially one or a plurality of the low-coercive partial areas (34).
5. The security element according to at least one of claims 1 to 4, characterized in that the high-coercive magnetic area (22; 32; 42; 52) completely overlaps the low-coercive magnetic area (24; 34; 44; 54).
6. The security element according to at least one of claims 1 to 5, characterized in that the low-coercive magnetic area (24; 34; 44; 54) has a coercive force of between approx. 10 and approx. 500 Oe (800 A/m to 40 kA/m), preferably between approx. 150 and approx. 350 Oe (12 kA/m to 28 kA/m).
7. The security element according to at least one of claims 1 to 6, characterized in that the low-coercive magnetic area (24; 34; 44; 54) is formed in a material layer, which contains iron oxides, pure iron, nickel or another soft magnetic material.
8. The security element according to at least one of claims 1 to 7, characterized in that the low-coercive magnetic area (24; 34; 44; 54) is formed in a material layer having a thickness of approx. 0.05 microns to approx. 20 microns.
9. The security element according to at least one of claims 1 to 8, characterized in that the high-coercive magnetic area (22; 32; 42; 52) has a coercive force above approx. 300 Oe (24 kA/m), preferably above approx. 1000 Oe (80 kA/m), especially preferred above approx. 2000 Oe (160 kA/ m).
10. The security element according to at least one of claims 1 to 9, characterized in that the high-coercive magnetic area (22; 32; 42; 52) is formed in a material layer, which contains an alloy of iron/cobalt/nickel or iron/cobalt/vanadium or platinum/cobalt or aluminum/nickel/ cobalt or iron/cobalt/chromium or samarium/cobalt or samarium/copper or samarium/iron or samarium/zirconium or neodymium/iron or neodymium/boron or another hard magnetic material.
11. The security element according to at least one of claims 1 to 10, characterized in that the high-coercive magnetic area (22; 32; 42; 52) is formed in a material layer having a thickness of approx. 0.05 microns to approx. 20 microns.
12. The security element according to at least one of claims 1 to 11, characterized in that the low-coercive (24; 34; 44) and the high-coercive magnetic area (22; 32; 42) are disposed one above the other on a common carrier (20; 30; 40).
13. The security element according to at least one of claims 1 to 11, characterized in that the low-coercive (54) and the high-coercive magnetic area (52) are disposed on opposite sides of a common carrier (50).
14. The security element according to one of claims 12 or 13, characterized in that the low-coercive (24; 34; 44; 54) and the high-coercive magnetic area (22; 32; 42; 52) are applied onto the common carrier (20; 30; 40; 50) with the help of a printing operation or a vacuum vapor deposition process.
15. The security element according to at least one of claims 1 to 14, characterized in that a further high-coercive magnetic area is provided for storing a switching state of the security element.
16. The security element according to at least one of claims 1 to 15, characterized in that a cover layer opaque at least in partial areas is provided, which hides position and arrangement of the low-coercive magnetic area (24; 34; 44; 54).
17. The security element according to claim 16, characterized in that the cover layer has gaps in the form of characters or patterns, which form an information visually readable and/or machine readable.
18. The security element according to at least one of claims 1 to 17, characterized in that the security element forms a security thread (12), a security strip, a patch or a transfer element (14) in particular on a transfer foil.
19. A security paper having a security element according to at least one of claims 1 to 18.
20. A document of value, such as bank note, passport, identification document or the like, having a security element (12, 14) according to at least one of claims 1 to 18.
21. The document of value according to claim 20, characterized in that the security element (12, 14) is contained on a carrier (20; 30; 40; 50) in the document of value.
22. The document of value according to claim 20, characterized in that the low-coercive (54) and the high-coercive magnetic area (52) of the security element are disposed on the same side or on opposite sides of the document of value (50).
23. The document of value according to at least one of claims 20 to 22, characterized in that the low-coercive magnetic area (24; 34; 44; 54) of the security element is provided with a magnetic code.
24. The document of value according to at least one of claims 20 to 23, characterized in that the document of value is marked by magnetizing the high-coercive magnetic area (22; 32; 42; 52) of the security element.
25. The document of value according to at least one of claims 20 to 24, characterized in that in the document of value is provided a further high-coercive magnetic area (16) for storing a switching state of the document of value.
26. A method for producing a security element according to any of claims 1 to 18, characterized in that the low-coercive and the high-coercive magnetic area are printed or vapor-deposited onto a common substrate or onto a document of value.
27. A method for checking a document of value according to at least one of the claims 20 to 25, wherein

    a) the low-coercive magnetic area of the security element or partial areas thereof are magnetized,

    b) the high-coercive magnetic area of the security element is magnetized, when the document of value is to be provided with a marking,

    c) the remanent magnetization of the low-coercive magnetic area or partial areas thereof is determined, and

    d) on the basis of the given remanent magnetization is determined, whether the document of value is provided with a marking or not.
28. The method according to claim 27, characterized in that in step b) the high-coercive magnetic area is magnetized perpendicular to a predetermined magnetization direction of the low-coercive magnetic area.
29. The method according to claim 27, characterized in that in step b) the high-coercive magnetic area is magnetized in parallel to a predetermined magnetization direction of the low-coercive magnetic area.
30. The method according to at least one of claims 27 to 29, characterized in that the paper of value contains a long stretched security element with a longitudinal axis, and the low-coercive partial areas are magnetized in a direction perpendicular to the longitudinal axis.
31. The method according to at least one of claims 27 to 30, characterized in that after marking the document of value the high-coercive magnetic area is demagnetized, so that the low-coercive magnetic code of the security element can be re-activated.
32. The method according to at least one of claims 27 to 31, characterized in that if a marking of the document of value is detected, the functional ability of the document of value will be changed, in particular restricted.

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