Title of Invention	SECURITY ELEMENT FOR DOCUMENTS OF VALUE
Abstract	The invention relates to a security element for securing value documents which has magnetic material. Further, the invention relates to a value document, a transfer material and a method for checking such a security element or value document. Along the security element, for example along a longitudinal direction of the security element, there are disposed one or more, maximally five, magnetic areas and one or more, maximally five, gap areas. The extension of the magnetic areas or the gap areas along the security element is preferably chosen so great that the magnetic signals of adjacent magnetization steps that arise upon transport of the security element past the magnetic sensor interfere constructively with each other.

Title of Invention

SECURITY ELEMENT FOR DOCUMENTS OF VALUE

Abstract

The invention relates to a security element for securing value documents which has magnetic material. Further, the invention relates to a value document, a transfer material and a method for checking such a security element or value document. Along the security element, for example along a longitudinal direction of the security element, there are disposed one or more, maximally five, magnetic areas and one or more, maximally five, gap areas. The extension of the magnetic areas or the gap areas along the security element is preferably chosen so great that the magnetic signals of adjacent magnetization steps that arise upon transport of the security element past the magnetic sensor interfere constructively with each other.

Full Text	Security element for value documents [0001] This invention relates to a security element for securing value documents which has magnetic material. Further, the invention relates to a value document and to a film material having the security element and to a method for checking such a security element or value document. [0002] A value document refers for the purposes of the invention to bank notes, but also shares, deeds, postage stamps, checks, admission tickets, travel tickets, air tickets, identity cards, visa stickers and the like, as well as labels, seals, packages, security paper or other elements for product protection. Therefore, the simplifying designation "value document" will hereinafter always include documents of the stated kind. [0003] It is known that bank notes, for example, have magnetic material which is used for checking the authenticity of the bank notes. Such magnetic material is for example a component of printing inks and applied to the bank notes upon printing thereof. For checking the authenticity of the bank notes, the distribution of the magnetic material produced upon printing can be determined and compared to a specification. Further, it is known that magnetic material can be contained in security elements applied to the bank note. For example, security threads can have magnetic material which can be applied either continuously or in the form of a coding. [0004] Further, it is known to embed security threads in bank-note paper partially or completely. A partially embedded security thread is visible only in certain places on the surface of the bank note, for example in periodically disposed windows in the bank-note paper. Upon viewing in reflected light, such a (continuously metallized) windowed security thread appears as a periodically visible metallization strip extending e.g. perpendicular to the longitudinal direction of the bank note. [0005] For imitating a windowed security thread, forgers affix for example metallized film strips to forged bank notes which resemble a windowed security thread when viewed in reflected light. It has turned out that such forgeries cause a certain (inductive) measuring signal upon examination with magnetic sensors, although the metallized film strip has no magnetic material. On the other hand, authentic bank notes that are in a poor state can also cause a similar measuring signal. Hence, upon checking the bank notes there is a risk of bank notes that are authentic but in a poor state being incorrectly considered to be forgeries with thus imitated security threads and being mistakenly sorted out. [0006] Hence, the invention is based on the object of providing a more easily verifiable security element, a value document having the security element, and a film material having the security element, and an improved measuring method for checking value documents having the security element. [0007] This object is achieved by the features of the independent claims. Developments are the object of the subclaims. [0008] According to the invention, the security element has magnetic material which is applied to or incorporated in the security element. In particular, the security element possesses a magnetic coding which is formed by a certain arrangement of magnetic areas and gap areas. The security element has at least one magnetic area which continuously contains magnetic material and at least one gap area which continuously contains no magnetic material and/or which continuously has a lower rema- nent flux density than the magnetic area. The term "continuously" is to be understood for the purposes of this application as continuously along an imaginary straight line. The magnetic and gaps areas are disposed along the security element along a given direction which preferably extends parallel to a longitudinal direction of the security element. The longitudinal direction of the security element refers here to the direction in which the security element possesses its greatest extension. [0009] To permit a clear differentiation from the imitated windowed security threads mentioned at the outset, a magnetic coding is applied, for example in the form of a few individual gap areas within an otherwise continuously magnetic security element. Alternatively, the magnetic coding can also be applied in form of a few individual magnetic areas which within a security element which is otherwise free from magnetic material or which otherwise continuously has magnetic properties which deviate from those of the magnetic areas. Preferably, the magnetic areas and/or the gap areas are disposed in or on the security element such that they differ from the arrangement of the windows on or in the substrate of the value document where the security ele- ment is visible on at least one surface of the value document, such as of the bank-note paper, or where the security element passes to at least one surface of the value docu- ment. The magnetic areas or the gap areas can be disposed along the security element for example periodically, but with a period deviating from the window period, but they can also be present on the security element in the form of individual non-periodically disposed areas. The security element has maximally five magnetic areas and/or maxi- mally five gap areas along the given direction. However, the security element prefera- bly possesses only maximally four or maximally three magnetic areas and/or gap areas along the given direction. It is in particular also possible, however, to use a security element with only one or with two magnetic areas and/or gap areas along the given direction. The statement of a number of magnetic areas or gaps areas along a given direction refers to the number of magnetic areas or gap areas in or on the security ele- ment that exist along an imaginary, straight line over the total security element. [0010] The magnetic areas and/or gaps areas extend in one embodiment across the total width of the security element. The width of the security element is the extension perpendicular to the given direction along which the magnetic areas and/or gap areas are disposed, i.e. for example the extension of the magnetic areas and/or gap areas perpendicular to the longitudinal direction of the security element. In a further em- bodiment, the magnetic areas are disposed in one or in both edge areas of the security element. They can form one or more edge tracks disposed in or on the security element parallel to the given direction. For example, the magnetic areas of the security element can form two edge tracks extending parallel to each other. In or on the areas of the se- curity element disposed outside the magnetic areas there can be provided identifying elements such as characters, symbols, text or also patterns. Said identifying elements can identify the security element individually, i.e. according to its area of application, e.g. according to the kind of value document to be secured. The identifying elements can be disposed on or in the security element outside the edge tracks, for example be- tween the two edge tracks. [0011] In a first embodiment, at least one magnetic area is extended along the given direction over at least 15 mm, preferably over at least 20 mm, particularly preferably over 20 mm to 40 mm. For example, all those magnetic areas that are limited along the given direction by gap areas - which excludes those magnetic areas that are limited along the given direction by an edge of the security element - extend over at least 15 mm, preferably over at least 20 mm, particularly preferably over 20 mm to 40 mm. In said first embodiment, at least one gap area - preferably all gap areas that are limited along the given direction by magnetic areas - extend along the given direction for ex- ample over 1 mm to 5 mm, preferably over 2 mm to 4 mm, particularly preferably over about 3 mm. [0012] In a second embodiment, which is complementary to the first embodiment, at least one gap area extends along the given direction over at least 15 mm, preferably over at least 20 mm, particularly preferably over 20 mm to 40 mm. Preferably, all gap areas that are limited along the given direction by magnetic areas - which excludes those gap areas that are limited along the given direction by an edge of the security element - are extended over at least 15 mm, preferably over at least 20 mm, particu- larly preferably over 20 mm to 40 mm. For example, in said second embodiment, at least one magnetic area - preferably all those magnetic areas that are limited by gap areas along the given direction - extend along the given direction for example over 1 mm to 5 mm, preferably over 2 mm to 4 mm, particularly preferably over about 3 mm. [0013] For realizing a continuously lower remanent flux density in a gap area, there can be chosen in the gap area for example a lower concentration of magnetic material than in the magnetic area. Alternatively or additionally, it is also possible that a smaller layer thickness or also a smaller width of the magnetic material or also a dif- ferent magnetic material is applied in the gap area than in the magnetic area. In the gap area the remanent flux density and/or the concentration of magnetic material and/or the layer thickness and/or the width of magnetic material can be for example less than 50%, in particular less than 10%, of the remanent flux density and/or the concentration of magnetic material and/or the layer thickness and/or the width of magnetic material in the magnetic area. [0014] In an especially preferred embodiment, the extension of the gap areas or the magnetic areas is so chosen that there results a constructive interference of the mag- netic signals, in particular of the individual pulses, which are detected by a magnetic sensor at the beginning and at the end of the particular area. By means of the construc- tive interference of individual pulses there is obtained on the magnetic sensor a meas- uring signal with a greater maximum amplitude than the individual pulses themselves have. This can be used advantageously in the case of relatively small signal amplitudes as occur for example with the magnetic signals of security threads in transverse trans- port of bank notes. [0015] The magnetic areas and gap areas are limited along the given direction by magnetization steps. A magnetization step is understood for the purposes of the appli- cation to be a steplike change in remanent flux density which arises at the transition between a magnetic area and a gap area. In a first embodiment, the gap areas are lim- ited along the given direction by a first and a second magnetization step. The first magnetization step of the gap area has a steplike drop in remanent flux density and/or concentration and/or layer thickness and/or width of the magnetic material, and the second magnetization step of the gap area has a steplike increase in remanent flux den- sity and/or concentration and/or layer thickness and/or width of the magnetic material. The distance between the magnetization steps is preferably chosen so great along the given direction that the magnetic signals of the first and second magnetization steps of the gap area interfere constructively with each other. In other words, the extension of the gap area along the given direction is chosen so great that the magnetic signals of the two transitions from the magnetic area preceding upon the magnetic-signal meas- urement to the gap area and from the gap area to the magnetic area following upon the magnetic-signal measurement interfere constructively. [0016] In a second embodiment, the magnetic areas are limited along the given di- rection by a first and a second magnetization step. The first magnetization step of the magnetic area has a steplike increase in remanent flux density and/or concentration and/or layer thickness and/or width of the magnetic material, and the second magneti- zation step of the magnetic area has a steplike drop in remanent flux density and/or concentration and/or layer thickness and/or width of the magnetic material. The dis- tance between the magnetization steps is preferably chosen so great along the given direction that the magnetic signals of the first and second magnetization steps of the magnetic area interfere constructively with each other. In other words, the extension of the magnetic area along the given direction is chosen so great that the magnetic signals of the two transitions from the gap area preceding upon the magnetic-signal measure- ment to the magnetic area and from the magnetic area to the gap area following upon the magnetic-signal measurement interfere constructively. [0017] The magnetic material used is for example magnetic pigments. The magnetic material has for example magnetically hard material, preferably one or more different iron compounds, particularly preferably one or more different iron oxides or magnet- ite. [0018] The security element can either be produced directly on the value document or be prepared on a separate substrate. If it would cause difficulties to provide the value document directly with the magnetic materials for example, it may be expedient to prepare the construction of the security element at least partly on the separate sub- strate. The separate substrate to which the security element can be applied preferably has plastic and can be, or have, for example a film material, in particular a transfer ma- terial. [0019] The security element, in particular the magnetic materials of the security element, can be applied for example in endless form to a carrier material of the transfer material. The fastening of the security element to a value document to be secured is effected here by means of an adhesive layer which is applied either to the value docu- ment or also to the uppermost layer of the transfer material. Preferably, a hot-melt ad- hesive is used therefor. To define the outline form of the security element, either an adhesive layer can be provided only in the areas to be transferred, or the adhesive is activated only in the areas to be transferred. After transfer, the carrier material of the transfer material is removed, leaving only the security element on the value document to be secured. [0020] The value document to which the security element is applied may be for ex- ample a security paper, a security document, but also product packages. Other objects of value requiring security-type protection can of course also be provided with the in- ventive security element. [0021] The security element can be applied for example to value documents in or on whose substrate, such as security paper, one or more windows are present. To improve the differentiation of authentic value documents from the forgeries mentioned at the outset, the gap areas and/or magnetic areas of the security element are disposed along the value document differently from the windows along the value document. The number of gap areas and/or the number of magnetic areas along the security element is preferably lower, preferably at least three lower, than the number of windows in or on the substrate of the value document where the security element is visible on at least one surface of the value document or where the security element passes to at least one surface of the value document. [0022] Furthermore, the invention relates to a method for checking value documents having one or more security elements wherein magnetic signals of the security element are measured. For checking the value document or the security element, the value document is transported past a magnetic sensor, and the magnetic signals of the secu- rity element are sensed by means of the magnetic sensor and supplied to an evaluation device. The transport direction of the value documents is for example parallel to the longitudinal direction of the security element which is disposed in or on the value document. Preferably, the magnetic areas and gap areas are so disposed along the se- curity element that at least the magnetic signals of two adjacent magnetization steps that limit a gap area or a magnetic area interfere constructively. The constructive inter- ference of the magnetic signals can be obtained for example with magnetic sensors that operate inductively or also magnetoresistively. [0023] The constructive interference of the magnetic signals of adjacent magnetiza- tion steps makes it possible to obtain an increase in maximum amplitude of the mag- netic signal compared with the pulse provided by the magnetic signal of an individual magnetization step. This permits value documents or security elements with relatively weak magnetic signals arising from the individual magnetization steps to be checked for their magnetic properties more reliably. [0024] Further advantages and embodiments of the invention will be explained more closely with reference to the figures. For reasons of clarity, the invention will be explained more closely only by the example of a bank note. However, it is evident that the invention can readily be used for the above-mentioned value documents. [0025] There are shown: Figure 1 a schematically shown arrangement comprising a magnetic sensor and a bank note being transported past the magnetic sensor and having an inventive security element (magnetic areas and gap areas not shown), Figures 2a-d four exemplary embodiments of a bank note having an inventive secu- rity element in each case, Figures 3a-c an embodiment of a bank note having an inventive security element (Fig. 3a) as well as exemplary embodiments of the security element along the line A-A in cross section (Figs. 3b, 3c), Figures 4a-c schematic views of the magnetic signals SI, S2 of the two magnetiza- tion steps of a gap area, and of the superimposition of said magnetic signals to form the resulting magnetic signal S3 upon constructive in- terference. [0026] In Figure 1 there is shown schematically a detail of an apparatus for check- ing bank notes for their magnetic properties. Bank notes 1 or security elements 2 to be checked are transported through the apparatus by a transport system (not shown) along the transport direction shown by the arrow in Figure 1. In the shown example, a bank note 1 is transported past an inductively operating magnetic sensor 10 in transverse transport. In so doing, the security element 2 which is disposed with its longitudinal direction along the transport direction of the bank note 1 is checked for its magnetic properties. The security element 2 is for example a security thread which is partially embedded in the bank-note substrate and passes to the surface thereof, or is visible on the surface thereof, only at windows 7. The magnetic sensor possesses a plurality of measuring tracks 8 which are disposed along a line perpendicular to the transport di- rection of the bank notes. The inductively operating magnetic sensor 10 recognizes as magnetic signals in each case temporal changes of magnetic properties in the recording area of the individual measuring tracks 8 of the magnetic sensor. When a security ele- ment 2 is transported past that is provided continuously with magnetic material and whose magnetic properties are constant along the security element, the particular measuring tracks 8 would detect magnetic signals only at the beginning and end of the security element 2. However, when a security element 2 is transported past that has one or more interruptions or gap areas in the magnetic material, additional magnetic signals arise at said interruptions or gap areas. The magnetic signals are transmitted by the magnetic sensor 10 to an evaluation device 9 which checks the authenticity and/or currency and/or denomination of the bank note 1. [0027] Figure 2 shows four exemplary embodiments of a bank note 1 made of paper or plastic which is provided with a security element 2 in the form of a strip extending across the total width of the bank note 1. The bank note 1 can of course have further security features, such as a watermark, steel gravure printing, security thread, lumines- cent prints, etc. The security element 2 is disposed on the bank note 1, e.g. printed on, affixed or incorporated in the bank note 1. Along the security element 2 there are dis- posed a plurality of magnetic areas 3a-e with magnetic material, and a plurality of gap areas 4a-d which either have no magnetic material or have a lower remanent flux den- sity than the magnetic areas 3a-e. This can be obtained e.g. by a corresponding choice of the layer thicknesses of the areas 3a-e, 4a-d and/or by a corresponding choice of the concentrations and/or width of the magnetic materials in the areas 3a-e, 4a-d and/or a corresponding choice of the materials in the areas 3a-e, 4a-d. In the shown examples, the magnetic areas 3a-e are disposed in the edge area of the security element 2 (the upper one in Figure 2) and form an (upper) edge track parallel to the longitudinal di- rection of the security element 2. Furthermore, the shown security element 2 has fur- ther magnetic areas which are disposed parallel to the magnetic areas 3a-e and form a second (lower) edge track. Between the two edge tracks, which are in each case e.g. 0.2 to 0.4 mm wide, the security element 2 can additionally have identifying elements (not shown). By disposing two edge tracks with magnetic areas in or on the security element it is possible to realize a security element 2 which can both be provided with identifying elements and provide sufficient magnetic signal. [0028] In the example of Figure 2a, the security element 2 has only one gap area 4a and two magnetic areas 3a-b along its longitudinal direction. However, the security element 2 can also be equipped with a plurality of gap areas and a corresponding plu- rality of magnetic areas along the security element, as shown by the examples of Fig- ure 2b with two gap areas 4a-b and three magnetic areas 3a-c, of Figure 2c with three gap areas 4a-c and four magnetic areas 3a-d, and of Figure 2d with four gap areas 4a-d and five magnetic areas 3a-e. In said examples there are few, relatively short gap areas disposed along the otherwise magnetic edge tracks of the security element. Alterna- tively, the magnetic areas and gap areas can also be disposed along the edge tracks conversely, so to speak as the negative image of the arrangements from Figures 2a-d. In said examples there would then be few, relatively short magnetic areas disposed along the security element edge tracks otherwise provided with gap areas. [0029] In Figure 3a is an embodiment of a bank note 1 having a security element 2 which has two magnetic areas 3a, 3b and one gap area 4a along its longitudinal direc- tion. The security element 2 is partially embedded in the substrate of the bank note 1, so that the security element 2, which is e.g. a windowed security thread, is visible only in windows 7. The security element 2 can also be embedded completely in the sub- strate of the bank note 1. In both cases magnetic signals can be detected. [0030] With reference to Figures 3b-c some preferred embodiments will be ex- plained more closely, which show the bank note 1 in cross section along the dot- dashed line A-A to make the structure of the security element 2 clear. According to Figure 3b, there is incorporated in or applied to the paper substrate or plastic substrate of the bank note 1 a security element 2 having magnetic areas 3a, 3b and a gap area 4a. [0031] In the figures of the present application the inventive security element 2 is shown only schematically. What is essential to the inventive security element 2 is the number, arrangement and length of the magnetic areas and gap areas along the security element 2. To show the magnetic areas and gap areas of the inventive security element 2 more clearly, the figures hence omit the representation of further layers of the inven- tive security element 2. The actual realization of the layer structure can be effected according to the production methods known from the prior art. Thus, it is known e.g. from WO 92/11142 A1 to construct a security thread from a plurality of layers. It is possible at the same time to apply e.g. bars of magnetic material to a metal layer, cf. Figures 2 and 3 of said publication. The magnetic material can also be disposed within the layer structure, cf. the cross sections through the security threads of Figures 7 and 8 of said publication, which have two edge tracks with magnetic material parallel to the longitudinal direction of the security thread. The layer structure of the inventive security element 2 can be realized e.g. in the manner described in WO 92/11142 Al. [0032] In certain embodiments, e.g. security elements that are exposed to high me- chanical or chemical load during use, it is expedient to cover the magnetic areas and gap areas 3a, 3b, 4a with a protective layer 6. The protective layer 6 may be a film laminated over the security element 2, or a protective lacquer layer. The protective lacquer layer can be applied all over or in partial areas. For this purpose there can be used e.g. UV lacquers, hybrid lacquers, oleographic lacquers or dispersion lacquers of the one- or two-component type. The protective lacquer layer is preferably printed on, e.g. by flexographic printing or offset printing. [0033] The security element 2 can also be disposed on a plastic film 5 which can be applied to the bank note 1 or be incorporated in the bank note 1, cf. Figure 3c. The plastic film 5 with a layer comprising magnetic areas 3a, 3b and a gap area 4a disposed thereon can be affixed to the bank note 1, for example. For protection of the layer comprising magnetic areas 3 a, 3b and gap areas 4a, the latter can be covered with a protective layer 6. Departing therefrom, there can be applied in and/or on the plastic film 5 a layer comprising magnetic areas 3 a, 3b and gap areas 4a to which an adhesive layer (not shown) is finally applied for fastening the security element 2 to the bank note 1. In this case, an additional protective layer can be omitted, because the plastic film 5 forms a protective cover for the security element. In comparison to the represen- tation in Figure 3c this results in a reverse order of the security element 2 and the plas- tic film 5. [0034] In all above-described cases the adhesive can also be applied to the bank note 1, rather than to the security element 2, for fastening the security element 2 to the banknote 1. [0035] The security element 2 can also be configured as a so-called planchet which is preferably incorporated on the surface of the bank-note substrate. [0036] As described above, the security element 2 can be produced directly on the bank note 1 or be made available as a separate security element 2 and fastened to the bank note 1. However, it can also be envisaged to provide a separate security element 2 whose construction is only completed, e.g. provided with a protective layer, after the security element 2 has been fastened to the bank note 1. [0037] When the bank note 1 or the security element 2 is transported past a mag- netic sensor 10, there arises upon each change in the magnetic field of the security element 2 a measuring signal which can be evaluated by an evaluation device 9, for example a microcomputer, to permit statements to be made e.g. about the authenticity and/or the type of bank note, cf. Figure 1. [0038] In a security element 2 having a plurality of magnetic areas 3a-e and a plu- rality of gap areas 4a-d along a given direction, as described above, there exists - upon corresponding premagnetization of the security element 2 - a steplike change in mag- netization, i.e. a magnetization step, at each transition between a magnetic area and a gap area. When the security element 2 is transported past the magnetic sensor 10 there arises for each magnetization step a pulse in the measuring signal of at least one mag- netic track 8 of the magnetic sensor 10. Hence, the detected measuring signal shows not only pulses at the beginning and at the end of the passing security element 2, but, in addition, pulses upon passing of the places in the security element 2 where the mag- netic areas 3a-e and the gap areas 4a-d border on each other. [0039] In the case of a magnetization step representing a steplike drop in magnetiza- tion at the time t=tl - as is present e.g. in the case shown in Figure 4a between a mag- netic area 3a and a gap area 4 - there arises at the time t=tl in the measuring signal S1 of the magnetic sensor 10 a first pulse which has the shape sketched in Figure 4a. In the converse case of a steplike increase in magnetization - as is present e.g. between a gap area 4 and a magnetic area 3b, cf. Figure 4b - there arises at the time t=t2 in the measuring signal S2 of the magnetic sensor 10 a second pulse with the form sketched in Figure 4b, which is approximately point-symmetric to the shape of the first pulse. When a security element 2 is transported past that has both a steplike drop and a steplike increase in magnetization at a suitable distance apart - as is shown e.g. in Figure 4c with the areas 3a, b and 4a - there arises at the magnetic sensor 10 approximately a measuring signal S3 which results from the sum of the measuring signals SI and S2. The extension of the gap area 4a along the transport direction of the security element 2 is advantageously so chosen that the measuring signals S1 and S2 of the two magnetization steps interfere constructively with each other. At the time t=t3 there arises in the case of the constructive interference a pulse with a clearly higher maxi- mum amplitude than the maximum amplitudes of the individual pulses of the measur- ing signals SI and S2. [0040] For a constructive interference of the magnetic signals SI and S2 it is neces- sary that the first and second pulses at least partly overlap in time. Furthermore, it is necessary that the instantaneous amplitudes of the two pulses in this time overlap area add up to a higher instantaneous total amplitude in comparison to the instantaneous amplitudes of the individual pulses. These conditions are satisfied for example by the magnetic signals of Figures 4a-c. [0041] The distance between the magnetization steps necessary for a constructive interference, or the extension of the gap area or magnetic area whose magnetization steps are to cause constructively interfering magnetic signals, depends crucially on the temporal width of the individual pulses, in particular on the relative temporal position of the maxima of the first and second pulses. This can be subject to several influence variables. Generally, the temporal width of the individual pulses depends on the opera- tion mode, e.g. inductive or magnetoresistive, and the geometry of the magnetic sensor used. In the case of the inductively operating magnetic sensor 10, the shape of the magnetic signal is influenced e.g. by the spatial extension of the recording area of the magnetic sensor 10. Both the arrangement and the extension of pole shoes by which the inductive magnetic sensor 10 operates play a part here. Furthermore, the shape of the magnetic signal also depends on the distance (chosen perpendicular to the transport direction) between the passing security element 2 or value document 1 and the mag- netic sensor 10. The ideal distance between the magnetization steps in order for a con- structive interference of the magnetic signals to comes about thus depends on the par- ticular realization of the magnetic-signal measurement and must be determined experimentally in particular cases. In the shown example of the inductive magnetic sensor 10, said ideal distance is about 3 mm. Claims 1. A security element (2) for securing value documents (1), in particular bank notes (1), the security element (2) having at least one magnetic area (3a-e) which con- tinuously contains magnetic material, and at least one gap area (4a-d) which con- tinuously contains no magnetic material or which continuously has a lower re- manent flux density than the magnetic area (3a-e), the at least one magnetic area (3a-e) and the at least one gap area (4a-d) being disposed along a given direction, characterized in that the security element (2) has maximally five magnetic areas (3a-e) and/or has maximally five gap areas (4a-d) along the given direction. 2. The security element (2) according to claim 1, characterized in that the security element (2) has maximally four, preferably maximally three, particularly prefera- bly one or two, magnetic areas (3a-e) and/or maximally four, preferably maxi- mally three, particularly preferably one or two, gap areas (4a-d) along the given direction. 3. The security element (2) according to one or more of the preceding claims, char- acterized in that the given direction extends parallel to a longitudinal direction of the security element (2). 4. The security element (2) according to one or more of the preceding claims, char- acterized in that the magnetic areas (3a-e) and/or the gap areas (4a-d) extend across the total width of the security element (2). 5. The security element (2) according to one or more of claims 1 to 3, characterized in that the magnetic areas (3a-e) are disposed in an edge area of the security ele- ment (2), and the magnetic areas (3a-e) preferably form an edge track extending in the given direction. 6. The security element (2) according to one or more of claims 1 to 3 and 5, charac- terized in that the security element (2) has further magnetic areas along a direc- tion extending parallel to the given direction, the magnetic areas (3a-e) and the further magnetic areas preferably forming two edge tracks extending parallel to each other. 7. The security element (2) according to one or more of the preceding claims, characterized in that at least one magnetic area (3a-e) or at least one gap area (4a-d) extends along the given direction over at least 15 mm, preferably over at least 20 mm, particularly preferably over 20 mm to 40 mm. 8. The security element (2) according to one or more of the preceding claims, characterized in that all magnetic areas (3a-e) that are limited along the given direction by gap areas (4a-d), or all gap areas (4a-d) that are limited along the given direction by magnetic areas (3a-e), extend along the given direction over at least 15 mm, preferably over at least 20 mm, particularly preferably over 20 mm to 40 mm. 9. The security element (2) according to one or more of the preceding claims, characterized in that the continuously lower remanent flux density of the gap area (4a-d) is obtained by a lower concentration of the magnetic material and/or by a lower layer thickness and/or by a lower width of the magnetic material and/or by a different magnetic material in the gap area (4a-d) than in the magnetic area (3a- e). 10. The security element (2) according to one or more of the preceding claims, char- acterized in that the remanent flux density and/or the concentration and/or the layer thickness and/or the width of the magnetic material of the gap area (4a-d) is less than 50%, preferably less than 10%, of the remanent flux density and/or the concentration and/or the layer thickness and/or the width of the magnetic mate- rial. 11. The security element (2) according to one or more of the preceding claims, char- acterized in that at least one gap area (4a-d) that is limited along the given direc- tion by magnetic areas (3a-e), or at least one magnetic area (3a-e) that is limited along the given direction by gap areas (4a-d), extends along the given direction - 17- over 1 mm to 5 mm, preferably over 2 mm to 4 mm, particularly preferably over about 3 mm. 12. The security element (2) according to one or more of the preceding claims, char- acterized in that all those gap areas (4a-d) that are limited along the given direc- tion by magnetic areas (3a-e), or all those magnetic areas (3a-e) that are limited along the given direction by gap areas (4a-d), extend along the given direction over 1 mm to 5 mm, preferably over 2 mm to 4 mm, particularly preferably over about 3 mm. 13. The security element (2) according to one or more of the preceding claims, char- acterized in that at least one gap area (4a-d) is limited along the given direction by a first and a second magnetization step, the first magnetization step having a steplike drop in the remanent flux density and/or the concentration and/or the layer thickness and/or the width of the magnetic material, and the second mag- netization step having a steplike increase in the remanent flux density and/or the concentration and/or the layer thickness and/or the width of the magnetic mate- rial. 14. The security element (2) according to one or more of claims 1 to 12, character- ized in that at least one magnetic area (3a-e) is limited along the given direction by a first and a second magnetization step, the first magnetization step having a steplike increase in the remanent flux density and/or the concentration and/or the layer thickness and/or the width of the magnetic material, and the second mag- netization step having a steplike drop in the remanent flux density and/or the concentration and/or the layer thickness and/or the width of the magnetic mate- rial. 15. The security element (2) according to either of claims 13 and 14, characterized in that the first and second magnetization steps have a distance apart along the given direction by which the magnetic signals of the first and second magnetiza- tion steps interfere constructively with each other. 16. The security element (2) according to one or more of the preceding claims, char- acterized in that the magnetic material has magnetically hard material, preferably at least one iron compound, in particular iron oxide. 17. The security element (2) according to one or more of the preceding claims, char- acterized in that the security element (2) is a security thread or a planchet or a la- bel. 18. A film material having at least one security element (2) according to one or more of claims 1 to 17. 19. The film material according to claim 18, characterized in that the film material is a transfer material. 20. A value document (1) having at least one security element (2) according to one or more of claims 1 to 17. 21. The value document (1) according to claim 20 having a substrate on and/or in which a plurality of windows are present where the security element (2) passes to at least one surface of the value document (1), characterized in that the arrange- ment of the magnetic areas (3a-e) and/or of the gap areas (4a-d) along the secu- rity element (2) differs from the arrangement of the windows (7) on and/or in the value document (1). 22. The value document (1) according to one or more of claims 20 to 21, character- ized in that the number of gap areas (4a-d) and/or the number of magnetic areas (3a-e) along the security element (2) is smaller than the number of windows (7). 23. The value document (1) according to one or more of claims 20 to 22, character- ized in that the value document (1) is a security paper, a security document or a product package. 24. A method for checking value documents (1) according to one or more of claims 20 to 23, wherein at least one security element (2) of the value document (1) has at least one gap area (4a-d) which is limited along a given direction by a first and a second magnetization step, the first magnetization step having a steplike drop in the remanent flux density and/or the concentration and/or the layer thickness and/or the width of the magnetic material, and the second magnetization step having a steplike increase in the remanent flux density and/or the concentration and/or the layer thickness and/or the width of the magnetic material, having the steps of: transporting the value document (1) past a magnetic sensor (10) for measuring the magnetic properties of the value document (1), sensing the magnetic signals of the security element (2) by means of the magnetic sensor (10), wherein the magnetic signals of the first and second magnetization steps of the gap area (4a-d) interfere constructively with each other. 25. The method for checking value documents (1) according to one or more of claims 20 to 23, wherein at least one security element (2) of the value document (1) has at least one magnetic area (3a-e) which is limited along a given direction by a first and a second magnetization step, the first magnetization step having a steplike increase in the remanent flux density and/or the concentration and/or the layer thickness and/or the width of the magnetic material, and the second magnetization step having a steplike drop in the remanent flux density and/or the concentration and/or the layer thickness and/or the width of the magnetic material, having the steps of: transporting the value document (1) past a magnetic sensor (10) for measuring the magnetic properties of the value document (1), sensing the magnetic signals of the security element (2) by means of the magnetic sensor (10), wherein the magnetic signals of the first and second magnetization steps of the magnetic area (3a-e) interfere constructively with each other. 26. The method according to either of claims 24 to 25, characterized in that the transport of the value document (1) past the magnetic sensor (10) is effected parallel to the given direction, in particular parallel to the longitudinal direction of the security element (2). The invention relates to a security element for securing value documents which has magnetic material. Further, the invention relates to a value document, a transfer material and a method for checking such a security element or value document. Along the security element, for example along a longitudinal direction of the security element, there are disposed one or more, maximally five, magnetic areas and one or more, maximally five, gap areas. The extension of the magnetic areas or the gap areas along the security element is preferably chosen so great that the magnetic signals of adjacent magnetization steps that arise upon transport of the security element past the magnetic sensor interfere constructively with each other.

Full Text

Security element for value documents
[0001] This invention relates to a security element for securing value documents
which has magnetic material. Further, the invention relates to a value document and to
a film material having the security element and to a method for checking such a security
element or value document.
[0002] A value document refers for the purposes of the invention to bank notes, but
also shares, deeds, postage stamps, checks, admission tickets, travel tickets, air tickets,
identity cards, visa stickers and the like, as well as labels, seals, packages, security paper
or other elements for product protection. Therefore, the simplifying designation
"value document" will hereinafter always include documents of the stated kind.
[0003] It is known that bank notes, for example, have magnetic material which is
used for checking the authenticity of the bank notes. Such magnetic material is for example
a component of printing inks and applied to the bank notes upon printing
thereof. For checking the authenticity of the bank notes, the distribution of the magnetic
material produced upon printing can be determined and compared to a specification.
Further, it is known that magnetic material can be contained in security elements
applied to the bank note. For example, security threads can have magnetic material
which can be applied either continuously or in the form of a coding.
[0004] Further, it is known to embed security threads in bank-note paper partially or
completely. A partially embedded security thread is visible only in certain places on
the surface of the bank note, for example in periodically disposed windows in the
bank-note paper. Upon viewing in reflected light, such a (continuously metallized)
windowed security thread appears as a periodically visible metallization strip extending
e.g. perpendicular to the longitudinal direction of the bank note.
[0005] For imitating a windowed security thread, forgers affix for example metallized
film strips to forged bank notes which resemble a windowed security thread
when viewed in reflected light. It has turned out that such forgeries cause a certain (inductive)
measuring signal upon examination with magnetic sensors, although the metallized
film strip has no magnetic material. On the other hand, authentic bank notes

that are in a poor state can also cause a similar measuring signal. Hence, upon checking
the bank notes there is a risk of bank notes that are authentic but in a poor state
being incorrectly considered to be forgeries with thus imitated security threads and
being mistakenly sorted out.
[0006] Hence, the invention is based on the object of providing a more easily verifiable
security element, a value document having the security element, and a film material
having the security element, and an improved measuring method for checking
value documents having the security element.
[0007] This object is achieved by the features of the independent claims. Developments
are the object of the subclaims.
[0008] According to the invention, the security element has magnetic material
which is applied to or incorporated in the security element. In particular, the security
element possesses a magnetic coding which is formed by a certain arrangement of
magnetic areas and gap areas. The security element has at least one magnetic area
which continuously contains magnetic material and at least one gap area which continuously
contains no magnetic material and/or which continuously has a lower rema-
nent flux density than the magnetic area. The term "continuously" is to be understood
for the purposes of this application as continuously along an imaginary straight line.
The magnetic and gaps areas are disposed along the security element along a given
direction which preferably extends parallel to a longitudinal direction of the security
element. The longitudinal direction of the security element refers here to the direction
in which the security element possesses its greatest extension.
[0009] To permit a clear differentiation from the imitated windowed security
threads mentioned at the outset, a magnetic coding is applied, for example in the form
of a few individual gap areas within an otherwise continuously magnetic security element.
Alternatively, the magnetic coding can also be applied in form of a few individual
magnetic areas which within a security element which is otherwise free from magnetic
material or which otherwise continuously has magnetic properties which deviate
from those of the magnetic areas. Preferably, the magnetic areas and/or the gap areas
are disposed in or on the security element such that they differ from the arrangement

of the windows on or in the substrate of the value document where the security ele-
ment is visible on at least one surface of the value document, such as of the bank-note
paper, or where the security element passes to at least one surface of the value docu-
ment. The magnetic areas or the gap areas can be disposed along the security element
for example periodically, but with a period deviating from the window period, but they
can also be present on the security element in the form of individual non-periodically
disposed areas. The security element has maximally five magnetic areas and/or maxi-
mally five gap areas along the given direction. However, the security element prefera-
bly possesses only maximally four or maximally three magnetic areas and/or gap areas
along the given direction. It is in particular also possible, however, to use a security
element with only one or with two magnetic areas and/or gap areas along the given
direction. The statement of a number of magnetic areas or gaps areas along a given
direction refers to the number of magnetic areas or gap areas in or on the security ele-
ment that exist along an imaginary, straight line over the total security element.
[0010] The magnetic areas and/or gaps areas extend in one embodiment across the
total width of the security element. The width of the security element is the extension
perpendicular to the given direction along which the magnetic areas and/or gap areas
are disposed, i.e. for example the extension of the magnetic areas and/or gap areas
perpendicular to the longitudinal direction of the security element. In a further em-
bodiment, the magnetic areas are disposed in one or in both edge areas of the security
element. They can form one or more edge tracks disposed in or on the security element
parallel to the given direction. For example, the magnetic areas of the security element
can form two edge tracks extending parallel to each other. In or on the areas of the se-
curity element disposed outside the magnetic areas there can be provided identifying
elements such as characters, symbols, text or also patterns. Said identifying elements
can identify the security element individually, i.e. according to its area of application,
e.g. according to the kind of value document to be secured. The identifying elements
can be disposed on or in the security element outside the edge tracks, for example be-
tween the two edge tracks.
[0011] In a first embodiment, at least one magnetic area is extended along the given
direction over at least 15 mm, preferably over at least 20 mm, particularly preferably

over 20 mm to 40 mm. For example, all those magnetic areas that are limited along the
given direction by gap areas - which excludes those magnetic areas that are limited
along the given direction by an edge of the security element - extend over at least 15
mm, preferably over at least 20 mm, particularly preferably over 20 mm to 40 mm. In
said first embodiment, at least one gap area - preferably all gap areas that are limited
along the given direction by magnetic areas - extend along the given direction for ex-
ample over 1 mm to 5 mm, preferably over 2 mm to 4 mm, particularly preferably over
about 3 mm.
[0012] In a second embodiment, which is complementary to the first embodiment,
at least one gap area extends along the given direction over at least 15 mm, preferably
over at least 20 mm, particularly preferably over 20 mm to 40 mm. Preferably, all gap
areas that are limited along the given direction by magnetic areas - which excludes
those gap areas that are limited along the given direction by an edge of the security
element - are extended over at least 15 mm, preferably over at least 20 mm, particu-
larly preferably over 20 mm to 40 mm. For example, in said second embodiment, at
least one magnetic area - preferably all those magnetic areas that are limited by gap
areas along the given direction - extend along the given direction for example over 1
mm to 5 mm, preferably over 2 mm to 4 mm, particularly preferably over about 3 mm.
[0013] For realizing a continuously lower remanent flux density in a gap area, there
can be chosen in the gap area for example a lower concentration of magnetic material
than in the magnetic area. Alternatively or additionally, it is also possible that a
smaller layer thickness or also a smaller width of the magnetic material or also a dif-
ferent magnetic material is applied in the gap area than in the magnetic area. In the gap
area the remanent flux density and/or the concentration of magnetic material and/or the
layer thickness and/or the width of magnetic material can be for example less than
50%, in particular less than 10%, of the remanent flux density and/or the concentration
of magnetic material and/or the layer thickness and/or the width of magnetic material
in the magnetic area.
[0014] In an especially preferred embodiment, the extension of the gap areas or the
magnetic areas is so chosen that there results a constructive interference of the mag-

netic signals, in particular of the individual pulses, which are detected by a magnetic
sensor at the beginning and at the end of the particular area. By means of the construc-
tive interference of individual pulses there is obtained on the magnetic sensor a meas-
uring signal with a greater maximum amplitude than the individual pulses themselves
have. This can be used advantageously in the case of relatively small signal amplitudes
as occur for example with the magnetic signals of security threads in transverse trans-
port of bank notes.
[0015] The magnetic areas and gap areas are limited along the given direction by
magnetization steps. A magnetization step is understood for the purposes of the appli-
cation to be a steplike change in remanent flux density which arises at the transition
between a magnetic area and a gap area. In a first embodiment, the gap areas are lim-
ited along the given direction by a first and a second magnetization step. The first
magnetization step of the gap area has a steplike drop in remanent flux density and/or
concentration and/or layer thickness and/or width of the magnetic material, and the
second magnetization step of the gap area has a steplike increase in remanent flux den-
sity and/or concentration and/or layer thickness and/or width of the magnetic material.
The distance between the magnetization steps is preferably chosen so great along the
given direction that the magnetic signals of the first and second magnetization steps of
the gap area interfere constructively with each other. In other words, the extension of
the gap area along the given direction is chosen so great that the magnetic signals of
the two transitions from the magnetic area preceding upon the magnetic-signal meas-
urement to the gap area and from the gap area to the magnetic area following upon the
magnetic-signal measurement interfere constructively.
[0016] In a second embodiment, the magnetic areas are limited along the given di-
rection by a first and a second magnetization step. The first magnetization step of the
magnetic area has a steplike increase in remanent flux density and/or concentration
and/or layer thickness and/or width of the magnetic material, and the second magneti-
zation step of the magnetic area has a steplike drop in remanent flux density and/or
concentration and/or layer thickness and/or width of the magnetic material. The dis-
tance between the magnetization steps is preferably chosen so great along the given
direction that the magnetic signals of the first and second magnetization steps of the

magnetic area interfere constructively with each other. In other words, the extension of
the magnetic area along the given direction is chosen so great that the magnetic signals
of the two transitions from the gap area preceding upon the magnetic-signal measure-
ment to the magnetic area and from the magnetic area to the gap area following upon
the magnetic-signal measurement interfere constructively.
[0017] The magnetic material used is for example magnetic pigments. The magnetic
material has for example magnetically hard material, preferably one or more different
iron compounds, particularly preferably one or more different iron oxides or magnet-
ite.
[0018] The security element can either be produced directly on the value document
or be prepared on a separate substrate. If it would cause difficulties to provide the
value document directly with the magnetic materials for example, it may be expedient
to prepare the construction of the security element at least partly on the separate sub-
strate. The separate substrate to which the security element can be applied preferably
has plastic and can be, or have, for example a film material, in particular a transfer ma-
terial.
[0019] The security element, in particular the magnetic materials of the security
element, can be applied for example in endless form to a carrier material of the transfer
material. The fastening of the security element to a value document to be secured is
effected here by means of an adhesive layer which is applied either to the value docu-
ment or also to the uppermost layer of the transfer material. Preferably, a hot-melt ad-
hesive is used therefor. To define the outline form of the security element, either an
adhesive layer can be provided only in the areas to be transferred, or the adhesive is
activated only in the areas to be transferred. After transfer, the carrier material of the
transfer material is removed, leaving only the security element on the value document
to be secured.
[0020] The value document to which the security element is applied may be for ex-
ample a security paper, a security document, but also product packages. Other objects
of value requiring security-type protection can of course also be provided with the in-
ventive security element.

[0021] The security element can be applied for example to value documents in or on
whose substrate, such as security paper, one or more windows are present. To improve
the differentiation of authentic value documents from the forgeries mentioned at the
outset, the gap areas and/or magnetic areas of the security element are disposed along
the value document differently from the windows along the value document. The
number of gap areas and/or the number of magnetic areas along the security element is
preferably lower, preferably at least three lower, than the number of windows in or on
the substrate of the value document where the security element is visible on at least
one surface of the value document or where the security element passes to at least one
surface of the value document.
[0022] Furthermore, the invention relates to a method for checking value documents
having one or more security elements wherein magnetic signals of the security element
are measured. For checking the value document or the security element, the value
document is transported past a magnetic sensor, and the magnetic signals of the secu-
rity element are sensed by means of the magnetic sensor and supplied to an evaluation
device. The transport direction of the value documents is for example parallel to the
longitudinal direction of the security element which is disposed in or on the value
document. Preferably, the magnetic areas and gap areas are so disposed along the se-
curity element that at least the magnetic signals of two adjacent magnetization steps
that limit a gap area or a magnetic area interfere constructively. The constructive inter-
ference of the magnetic signals can be obtained for example with magnetic sensors
that operate inductively or also magnetoresistively.
[0023] The constructive interference of the magnetic signals of adjacent magnetiza-
tion steps makes it possible to obtain an increase in maximum amplitude of the mag-
netic signal compared with the pulse provided by the magnetic signal of an individual
magnetization step. This permits value documents or security elements with relatively
weak magnetic signals arising from the individual magnetization steps to be checked
for their magnetic properties more reliably.
[0024] Further advantages and embodiments of the invention will be explained
more closely with reference to the figures. For reasons of clarity, the invention will be

explained more closely only by the example of a bank note. However, it is evident that
the invention can readily be used for the above-mentioned value documents.
[0025] There are shown:
Figure 1 a schematically shown arrangement comprising a magnetic sensor and
a bank note being transported past the magnetic sensor and having an
inventive security element (magnetic areas and gap areas not shown),
Figures 2a-d four exemplary embodiments of a bank note having an inventive secu-
rity element in each case,
Figures 3a-c an embodiment of a bank note having an inventive security element
(Fig. 3a) as well as exemplary embodiments of the security element
along the line A-A in cross section (Figs. 3b, 3c),
Figures 4a-c schematic views of the magnetic signals SI, S2 of the two magnetiza-
tion steps of a gap area, and of the superimposition of said magnetic
signals to form the resulting magnetic signal S3 upon constructive in-
terference.
[0026] In Figure 1 there is shown schematically a detail of an apparatus for check-
ing bank notes for their magnetic properties. Bank notes 1 or security elements 2 to be
checked are transported through the apparatus by a transport system (not shown) along
the transport direction shown by the arrow in Figure 1. In the shown example, a bank
note 1 is transported past an inductively operating magnetic sensor 10 in transverse
transport. In so doing, the security element 2 which is disposed with its longitudinal
direction along the transport direction of the bank note 1 is checked for its magnetic
properties. The security element 2 is for example a security thread which is partially
embedded in the bank-note substrate and passes to the surface thereof, or is visible on
the surface thereof, only at windows 7. The magnetic sensor possesses a plurality of
measuring tracks 8 which are disposed along a line perpendicular to the transport di-
rection of the bank notes. The inductively operating magnetic sensor 10 recognizes as
magnetic signals in each case temporal changes of magnetic properties in the recording

area of the individual measuring tracks 8 of the magnetic sensor. When a security ele-
ment 2 is transported past that is provided continuously with magnetic material and
whose magnetic properties are constant along the security element, the particular
measuring tracks 8 would detect magnetic signals only at the beginning and end of the
security element 2. However, when a security element 2 is transported past that has
one or more interruptions or gap areas in the magnetic material, additional magnetic
signals arise at said interruptions or gap areas. The magnetic signals are transmitted by
the magnetic sensor 10 to an evaluation device 9 which checks the authenticity and/or
currency and/or denomination of the bank note 1.
[0027] Figure 2 shows four exemplary embodiments of a bank note 1 made of paper
or plastic which is provided with a security element 2 in the form of a strip extending
across the total width of the bank note 1. The bank note 1 can of course have further
security features, such as a watermark, steel gravure printing, security thread, lumines-
cent prints, etc. The security element 2 is disposed on the bank note 1, e.g. printed on,
affixed or incorporated in the bank note 1. Along the security element 2 there are dis-
posed a plurality of magnetic areas 3a-e with magnetic material, and a plurality of gap
areas 4a-d which either have no magnetic material or have a lower remanent flux den-
sity than the magnetic areas 3a-e. This can be obtained e.g. by a corresponding choice
of the layer thicknesses of the areas 3a-e, 4a-d and/or by a corresponding choice of the
concentrations and/or width of the magnetic materials in the areas 3a-e, 4a-d and/or a
corresponding choice of the materials in the areas 3a-e, 4a-d. In the shown examples,
the magnetic areas 3a-e are disposed in the edge area of the security element 2 (the
upper one in Figure 2) and form an (upper) edge track parallel to the longitudinal di-
rection of the security element 2. Furthermore, the shown security element 2 has fur-
ther magnetic areas which are disposed parallel to the magnetic areas 3a-e and form a
second (lower) edge track. Between the two edge tracks, which are in each case e.g.
0.2 to 0.4 mm wide, the security element 2 can additionally have identifying elements
(not shown). By disposing two edge tracks with magnetic areas in or on the security
element it is possible to realize a security element 2 which can both be provided with
identifying elements and provide sufficient magnetic signal.

[0028] In the example of Figure 2a, the security element 2 has only one gap area 4a
and two magnetic areas 3a-b along its longitudinal direction. However, the security
element 2 can also be equipped with a plurality of gap areas and a corresponding plu-
rality of magnetic areas along the security element, as shown by the examples of Fig-
ure 2b with two gap areas 4a-b and three magnetic areas 3a-c, of Figure 2c with three
gap areas 4a-c and four magnetic areas 3a-d, and of Figure 2d with four gap areas 4a-d
and five magnetic areas 3a-e. In said examples there are few, relatively short gap areas
disposed along the otherwise magnetic edge tracks of the security element. Alterna-
tively, the magnetic areas and gap areas can also be disposed along the edge tracks
conversely, so to speak as the negative image of the arrangements from Figures 2a-d.
In said examples there would then be few, relatively short magnetic areas disposed
along the security element edge tracks otherwise provided with gap areas.
[0029] In Figure 3a is an embodiment of a bank note 1 having a security element 2
which has two magnetic areas 3a, 3b and one gap area 4a along its longitudinal direc-
tion. The security element 2 is partially embedded in the substrate of the bank note 1,
so that the security element 2, which is e.g. a windowed security thread, is visible only
in windows 7. The security element 2 can also be embedded completely in the sub-
strate of the bank note 1. In both cases magnetic signals can be detected.
[0030] With reference to Figures 3b-c some preferred embodiments will be ex-
plained more closely, which show the bank note 1 in cross section along the dot-
dashed line A-A to make the structure of the security element 2 clear. According to
Figure 3b, there is incorporated in or applied to the paper substrate or plastic substrate
of the bank note 1 a security element 2 having magnetic areas 3a, 3b and a gap area 4a.
[0031] In the figures of the present application the inventive security element 2 is
shown only schematically. What is essential to the inventive security element 2 is the
number, arrangement and length of the magnetic areas and gap areas along the security
element 2. To show the magnetic areas and gap areas of the inventive security element
2 more clearly, the figures hence omit the representation of further layers of the inven-
tive security element 2. The actual realization of the layer structure can be effected
according to the production methods known from the prior art. Thus, it is known e.g.

from WO 92/11142 A1 to construct a security thread from a plurality of layers. It is
possible at the same time to apply e.g. bars of magnetic material to a metal layer, cf.
Figures 2 and 3 of said publication. The magnetic material can also be disposed within
the layer structure, cf. the cross sections through the security threads of Figures 7 and
8 of said publication, which have two edge tracks with magnetic material parallel to
the longitudinal direction of the security thread. The layer structure of the inventive
security element 2 can be realized e.g. in the manner described in WO 92/11142 Al.
[0032] In certain embodiments, e.g. security elements that are exposed to high me-
chanical or chemical load during use, it is expedient to cover the magnetic areas and
gap areas 3a, 3b, 4a with a protective layer 6. The protective layer 6 may be a film
laminated over the security element 2, or a protective lacquer layer. The protective
lacquer layer can be applied all over or in partial areas. For this purpose there can be
used e.g. UV lacquers, hybrid lacquers, oleographic lacquers or dispersion lacquers of
the one- or two-component type. The protective lacquer layer is preferably printed on,
e.g. by flexographic printing or offset printing.
[0033] The security element 2 can also be disposed on a plastic film 5 which can be
applied to the bank note 1 or be incorporated in the bank note 1, cf. Figure 3c. The
plastic film 5 with a layer comprising magnetic areas 3a, 3b and a gap area 4a disposed
thereon can be affixed to the bank note 1, for example. For protection of the layer
comprising magnetic areas 3 a, 3b and gap areas 4a, the latter can be covered with a
protective layer 6. Departing therefrom, there can be applied in and/or on the plastic
film 5 a layer comprising magnetic areas 3 a, 3b and gap areas 4a to which an adhesive
layer (not shown) is finally applied for fastening the security element 2 to the bank
note 1. In this case, an additional protective layer can be omitted, because the plastic
film 5 forms a protective cover for the security element. In comparison to the represen-
tation in Figure 3c this results in a reverse order of the security element 2 and the plas-
tic film 5.
[0034] In all above-described cases the adhesive can also be applied to the bank
note 1, rather than to the security element 2, for fastening the security element 2 to the
banknote 1.

[0035] The security element 2 can also be configured as a so-called planchet which
is preferably incorporated on the surface of the bank-note substrate.
[0036] As described above, the security element 2 can be produced directly on the
bank note 1 or be made available as a separate security element 2 and fastened to the
bank note 1. However, it can also be envisaged to provide a separate security element
2 whose construction is only completed, e.g. provided with a protective layer, after the
security element 2 has been fastened to the bank note 1.
[0037] When the bank note 1 or the security element 2 is transported past a mag-
netic sensor 10, there arises upon each change in the magnetic field of the security
element 2 a measuring signal which can be evaluated by an evaluation device 9, for
example a microcomputer, to permit statements to be made e.g. about the authenticity
and/or the type of bank note, cf. Figure 1.
[0038] In a security element 2 having a plurality of magnetic areas 3a-e and a plu-
rality of gap areas 4a-d along a given direction, as described above, there exists - upon
corresponding premagnetization of the security element 2 - a steplike change in mag-
netization, i.e. a magnetization step, at each transition between a magnetic area and a
gap area. When the security element 2 is transported past the magnetic sensor 10 there
arises for each magnetization step a pulse in the measuring signal of at least one mag-
netic track 8 of the magnetic sensor 10. Hence, the detected measuring signal shows
not only pulses at the beginning and at the end of the passing security element 2, but,
in addition, pulses upon passing of the places in the security element 2 where the mag-
netic areas 3a-e and the gap areas 4a-d border on each other.
[0039] In the case of a magnetization step representing a steplike drop in magnetiza-
tion at the time t=tl - as is present e.g. in the case shown in Figure 4a between a mag-
netic area 3a and a gap area 4 - there arises at the time t=tl in the measuring signal S1
of the magnetic sensor 10 a first pulse which has the shape sketched in Figure 4a. In
the converse case of a steplike increase in magnetization - as is present e.g. between a
gap area 4 and a magnetic area 3b, cf. Figure 4b - there arises at the time t=t2 in the
measuring signal S2 of the magnetic sensor 10 a second pulse with the form sketched
in Figure 4b, which is approximately point-symmetric to the shape of the first pulse.

When a security element 2 is transported past that has both a steplike drop and a
steplike increase in magnetization at a suitable distance apart - as is shown e.g. in Figure 4c
with the areas 3a, b and 4a - there arises at the magnetic sensor 10 approximately
a measuring signal S3 which results from the sum of the measuring signals SI
and S2. The extension of the gap area 4a along the transport direction of the security
element 2 is advantageously so chosen that the measuring signals S1 and S2 of the two
magnetization steps interfere constructively with each other. At the time t=t3 there
arises in the case of the constructive interference a pulse with a clearly higher maxi-
mum amplitude than the maximum amplitudes of the individual pulses of the measur-
ing signals SI and S2.
[0040] For a constructive interference of the magnetic signals SI and S2 it is neces-
sary that the first and second pulses at least partly overlap in time. Furthermore, it is
necessary that the instantaneous amplitudes of the two pulses in this time overlap area
add up to a higher instantaneous total amplitude in comparison to the instantaneous
amplitudes of the individual pulses. These conditions are satisfied for example by the
magnetic signals of Figures 4a-c.
[0041] The distance between the magnetization steps necessary for a constructive
interference, or the extension of the gap area or magnetic area whose magnetization
steps are to cause constructively interfering magnetic signals, depends crucially on the
temporal width of the individual pulses, in particular on the relative temporal position
of the maxima of the first and second pulses. This can be subject to several influence
variables. Generally, the temporal width of the individual pulses depends on the opera-
tion mode, e.g. inductive or magnetoresistive, and the geometry of the magnetic sensor
used. In the case of the inductively operating magnetic sensor 10, the shape of the
magnetic signal is influenced e.g. by the spatial extension of the recording area of the
magnetic sensor 10. Both the arrangement and the extension of pole shoes by which
the inductive magnetic sensor 10 operates play a part here. Furthermore, the shape of
the magnetic signal also depends on the distance (chosen perpendicular to the transport
direction) between the passing security element 2 or value document 1 and the mag-
netic sensor 10. The ideal distance between the magnetization steps in order for a con-
structive interference of the magnetic signals to comes about thus depends on the par-

ticular realization of the magnetic-signal measurement and must be determined experimentally
in particular cases. In the shown example of the inductive magnetic sensor
10, said ideal distance is about 3 mm.

Claims
1. A security element (2) for securing value documents (1), in particular bank notes
(1), the security element (2) having at least one magnetic area (3a-e) which con-
tinuously contains magnetic material, and at least one gap area (4a-d) which con-
tinuously contains no magnetic material or which continuously has a lower re-
manent flux density than the magnetic area (3a-e), the at least one magnetic area
(3a-e) and the at least one gap area (4a-d) being disposed along a given direction,
characterized in that the security element (2) has maximally five magnetic areas
(3a-e) and/or has maximally five gap areas (4a-d) along the given direction.
2. The security element (2) according to claim 1, characterized in that the security
element (2) has maximally four, preferably maximally three, particularly prefera-
bly one or two, magnetic areas (3a-e) and/or maximally four, preferably maxi-
mally three, particularly preferably one or two, gap areas (4a-d) along the given
direction.
3. The security element (2) according to one or more of the preceding claims, char-
acterized in that the given direction extends parallel to a longitudinal direction of
the security element (2).
4. The security element (2) according to one or more of the preceding claims, char-
acterized in that the magnetic areas (3a-e) and/or the gap areas (4a-d) extend
across the total width of the security element (2).
5. The security element (2) according to one or more of claims 1 to 3, characterized
in that the magnetic areas (3a-e) are disposed in an edge area of the security ele-
ment (2), and the magnetic areas (3a-e) preferably form an edge track extending
in the given direction.
6. The security element (2) according to one or more of claims 1 to 3 and 5, charac-
terized in that the security element (2) has further magnetic areas along a direc-
tion extending parallel to the given direction, the magnetic areas (3a-e) and the

further magnetic areas preferably forming two edge tracks extending parallel to
each other.
7. The security element (2) according to one or more of the preceding claims, characterized
in that at least one magnetic area (3a-e) or at least one gap area (4a-d)
extends along the given direction over at least 15 mm, preferably over at least 20
mm, particularly preferably over 20 mm to 40 mm.
8. The security element (2) according to one or more of the preceding claims, characterized
in that all magnetic areas (3a-e) that are limited along the given direction
by gap areas (4a-d), or all gap areas (4a-d) that are limited along the given
direction by magnetic areas (3a-e), extend along the given direction over at least
15 mm, preferably over at least 20 mm, particularly preferably over 20 mm to 40
mm.
9. The security element (2) according to one or more of the preceding claims, characterized
in that the continuously lower remanent flux density of the gap area
(4a-d) is obtained by a lower concentration of the magnetic material and/or by a
lower layer thickness and/or by a lower width of the magnetic material and/or by
a different magnetic material in the gap area (4a-d) than in the magnetic area (3a-
e).
10. The security element (2) according to one or more of the preceding claims, char-
acterized in that the remanent flux density and/or the concentration and/or the
layer thickness and/or the width of the magnetic material of the gap area (4a-d) is
less than 50%, preferably less than 10%, of the remanent flux density and/or the
concentration and/or the layer thickness and/or the width of the magnetic mate-
rial.
11. The security element (2) according to one or more of the preceding claims, char-
acterized in that at least one gap area (4a-d) that is limited along the given direc-
tion by magnetic areas (3a-e), or at least one magnetic area (3a-e) that is limited
along the given direction by gap areas (4a-d), extends along the given direction

- 17-
over 1 mm to 5 mm, preferably over 2 mm to 4 mm, particularly preferably over
about 3 mm.
12. The security element (2) according to one or more of the preceding claims, char-
acterized in that all those gap areas (4a-d) that are limited along the given direc-
tion by magnetic areas (3a-e), or all those magnetic areas (3a-e) that are limited
along the given direction by gap areas (4a-d), extend along the given direction
over 1 mm to 5 mm, preferably over 2 mm to 4 mm, particularly preferably over
about 3 mm.
13. The security element (2) according to one or more of the preceding claims, char-
acterized in that at least one gap area (4a-d) is limited along the given direction
by a first and a second magnetization step, the first magnetization step having a
steplike drop in the remanent flux density and/or the concentration and/or the
layer thickness and/or the width of the magnetic material, and the second mag-
netization step having a steplike increase in the remanent flux density and/or the
concentration and/or the layer thickness and/or the width of the magnetic mate-
rial.
14. The security element (2) according to one or more of claims 1 to 12, character-
ized in that at least one magnetic area (3a-e) is limited along the given direction
by a first and a second magnetization step, the first magnetization step having a
steplike increase in the remanent flux density and/or the concentration and/or the
layer thickness and/or the width of the magnetic material, and the second mag-
netization step having a steplike drop in the remanent flux density and/or the
concentration and/or the layer thickness and/or the width of the magnetic mate-
rial.
15. The security element (2) according to either of claims 13 and 14, characterized in
that the first and second magnetization steps have a distance apart along the
given direction by which the magnetic signals of the first and second magnetiza-
tion steps interfere constructively with each other.

16. The security element (2) according to one or more of the preceding claims, char-
acterized in that the magnetic material has magnetically hard material, preferably
at least one iron compound, in particular iron oxide.
17. The security element (2) according to one or more of the preceding claims, char-
acterized in that the security element (2) is a security thread or a planchet or a la-
bel.
18. A film material having at least one security element (2) according to one or more
of claims 1 to 17.
19. The film material according to claim 18, characterized in that the film material is
a transfer material.
20. A value document (1) having at least one security element (2) according to one
or more of claims 1 to 17.
21. The value document (1) according to claim 20 having a substrate on and/or in
which a plurality of windows are present where the security element (2) passes to
at least one surface of the value document (1), characterized in that the arrange-
ment of the magnetic areas (3a-e) and/or of the gap areas (4a-d) along the secu-
rity element (2) differs from the arrangement of the windows (7) on and/or in the
value document (1).
22. The value document (1) according to one or more of claims 20 to 21, character-
ized in that the number of gap areas (4a-d) and/or the number of magnetic areas
(3a-e) along the security element (2) is smaller than the number of windows (7).
23. The value document (1) according to one or more of claims 20 to 22, character-
ized in that the value document (1) is a security paper, a security document or a
product package.
24. A method for checking value documents (1) according to one or more of claims
20 to 23, wherein at least one security element (2) of the value document (1) has
at least one gap area (4a-d) which is limited along a given direction by a first and

a second magnetization step, the first magnetization step having a steplike drop
in the remanent flux density and/or the concentration and/or the layer thickness
and/or the width of the magnetic material, and the second magnetization step
having a steplike increase in the remanent flux density and/or the concentration
and/or the layer thickness and/or the width of the magnetic material, having the
steps of:
transporting the value document (1) past a magnetic sensor (10) for measuring
the magnetic properties of the value document (1),
sensing the magnetic signals of the security element (2) by means of the
magnetic sensor (10),
wherein the magnetic signals of the first and second magnetization steps of the
gap area (4a-d) interfere constructively with each other.
25. The method for checking value documents (1) according to one or more of
claims 20 to 23, wherein at least one security element (2) of the value document
(1) has at least one magnetic area (3a-e) which is limited along a given direction
by a first and a second magnetization step, the first magnetization step having a
steplike increase in the remanent flux density and/or the concentration and/or the
layer thickness and/or the width of the magnetic material, and the second magnetization
step having a steplike drop in the remanent flux density and/or the
concentration and/or the layer thickness and/or the width of the magnetic material,
having the steps of:
transporting the value document (1) past a magnetic sensor (10) for measuring
the magnetic properties of the value document (1),
sensing the magnetic signals of the security element (2) by means of the
magnetic sensor (10),
wherein the magnetic signals of the first and second magnetization steps of the
magnetic area (3a-e) interfere constructively with each other.
26. The method according to either of claims 24 to 25, characterized in that the transport
of the value document (1) past the magnetic sensor (10) is effected parallel
to the given direction, in particular parallel to the longitudinal direction of the security
element (2).

The invention relates to a security element for securing value documents which has magnetic material. Further, the invention relates to a value document, a transfer material and a method for checking such a security element or value document. Along the security element, for example along a longitudinal direction of the security element, there are disposed one or more, maximally five, magnetic areas and one or more, maximally five, gap areas. The extension of the magnetic areas or the gap areas along
the security element is preferably chosen so great that the magnetic signals of adjacent
magnetization steps that arise upon transport of the security element past the magnetic sensor interfere constructively with each other.

Documents:

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Patent Number

269272

Indian Patent Application Number

1926/KOLNP/2009

PG Journal Number

42/2015

Publication Date

16-Oct-2015

Grant Date

13-Oct-2015

Date of Filing

22-May-2009

Name of Patentee

GIESECKE & DEVRIENT GMBH

Applicant Address

PRINZREGENTENSTR. 159, 81677 MÜNCHEN

Inventors:

#	Inventor's Name	Inventor's Address
1	SCHÜTZMANN, JÜRGEN	KARL-SCHWEIGER-STRASSE 5A, 85276 PFAFFENHOFEN
2	HEIM, MANFRED	SCHÖNSTRASSE 73A, 81543 MÜNCHEN

PCT International Classification Number

G07D 7/04

PCT International Application Number

PCT/EP2007/010039

PCT International Filing date

2007-11-20

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10 2006 055 169.9	2006-11-22	Germany