Magnetic security element and its method of fabrication

Abstract

A security element (1) for currency papers (90) or documents or the like, which comprises at least one magnetic element (2, 2') which can be at least partially magnetized. The magnetic element (2, 2') comprises a plurality of adjacent areas (4, 5) which are in mutual contact and are arranged side by side along at least one first longitudinal axis (Y) so as to form at least one row (6, 6a, 6b). The areas (4, 5) comprise: - at least one low-coercivity area (5) which has a first magnetic coercivity, and - at least one high-coercivity area (4) which has a second magnetic coercivity which is higher than the first magnetic coercivity.

Description

[0001] The present invention relates to a security element for currency papers (for example banknotes), documents, in particular security documents (for example passports), and the like, a method for manufacturing a security element and a document or currency paper.

[0002] In more detail, the security element according to the present invention is a magnetic element that contains a magnetic encoding or is in any case magnetically encodeable and is adapted, particularly but not exclusively, to be inserted in paper money, and in particular in the security threads that are inserted into the paper of banknotes, in order to certify the authenticity of the banknotes themselves, or into passports, or into any other document in order to certify its authenticity.

[0003] As is known, the first magnetic encoding systems for security threads were developed in the 80s, and as they have proved to be highly effective in distinguishing authentic documents from counterfeit ones, over the years they have evolved, increasing their level of complexity.

[0004] In particular, it is useful to refer to the magnetic code known as SISMA which was created in 1986 and is described in EP0310707.

[0005] The basic principle of this encoding consists of providing magnetic areas with different thicknesses, interleaved with empty spaces.

[0006] The recognition occurs by classifying all the bits and all the spaces as if it were waveform recognition. One simple method of recognition can be carried out by classifying the bits in sequence, by measuring the length of the bits with high thickness, of the bits with low thickness, and of the empty spaces.

[0007] Starting from the basic principle of the SISMA system, in 1989 a new encoding system was developed and is described in EP0428779.

[0008] This system is again based on free-format areas made with different thicknesses but made with two different types of magnetic pigment, suitably oriented and interleaved with spaces of free length.

[0009] Another encoding system called IMT is provided using a magnetic code as described by EP0407550, the basic principle of which consists of making magnetic areas and corresponding spaces of fixed length and then creating binary codes by filling this fixed measurement with magnetic ink (binary value "1") or not filling the fixed measurement (binary value "0").

[0010] The solution described in EP1618006, which again uses magnetic inks of different coercivity and is characterized in that the inks are superimposed on each other, has the peculiarity that the high-coercivity magnetic ink, when magnetized, in turn magnetizes the ink composed of low-coercivity oxides.

[0011] Another magnetic encoding system sold under the name TMC is made with a magnetic code as described in EP2229286 and EP2414176. The basic principle consists of making magnetic areas with different magnetic characteristics printed superimposed so that, suitably oriented, they generate at least three different codes which are read on two different channels.

[0012] The length of the bits and of the spaces is free and therefore the verification is carried out using waveform recognition. The aim is achieved by using a high-power permanent magnet (e.g. 10,000 Oe) to orient the magnetic inks (e.g. 4,000 Oe and 250 Oe) uniquely and in such a way that, for example, the peaks generated by the bits have the same intensity (bits magnetized to saturation); a second magnet is positioned so as to modify the magnetic orientation of the low-coercivity ink used for the superimposed printing, so leaving the magnetic characteristics of the high-coercivity inks unaltered.

[0013] In this way, the reading taken from the second channel will show the differences in intensity of the bits, which were made with two different magnetic inks.

[0014] A further magnetic encoding system sold under the name MAG3 is made with a magnetic code as described in EP 2588996. The substantial difference from the TMC thread is that it has an area, one of the superimposed printed areas, with a lower surface on at least two sides.

[0015] A typical conventional magnetic security element A is shown in Figures 1a and 1b, and has a series of individual magnetic elements B deposited on a plastic medium C interleaved with spaces D. Each magnetic element is magnetized uniformly throughout its volume.

[0016] By sliding a magneto-inductive head along the surface of the security element A, a signal m0 is obtained, as shown in Figure 1c.

[0017] Although the conventional magnetic security elements described above are numerous and useful, the need continues to be felt to improve the security of such measures, and in particular to obtain magnetic encodings that are harder to counterfeit.

[0018] DE 10 2004 049999, WO 2015 / 173753, GB 2 410 003, EP 0 310 707, EP 3 046 046 and VOLPE / VOLPE: "Magnetkarten", MAGNETKARTEN: GRUNDLAGEN, TECHNIK, ANWENDUNGEN, XX, XX, 1 January 1995 disclose security elements for currency papers or documents.

[0019] The aim of the present invention consists in improving the background art described above by providing a security element for currency papers or documents or the like that is capable of ensuring a higher level of security.

[0020] Within this aim, an object of the present invention is to provide a security element for currency papers or documents or the like that makes it possible to obtain encodings that are more complex or which are in any case harder to counterfeit.

[0021] Another object of the invention is to devise a security element for currency papers or documents or the like that is easy to implement and economically competitive when compared to the known art.

[0022] Another object of the invention is to provide an alternative to the background art.

[0023] This aim and these and other objects which will become more apparent hereinafter are achieved by a security element according to claim 1.

[0024] This aim and these and other objects which will become more apparent hereinafter are likewise achieved by a method according to claim 8.

[0025] Further characteristics and advantages of the invention will become better apparent from the description of some preferred, but not exclusive, embodiments of a security element, which are illustrated by way of nonlimiting example with the aid of the accompanying drawings wherein: Figures 1a, 1b and 1c are respectively a perspective view, a cross-sectional view and a magnetic signal, of a security element according to the prior art; Figure 2a is a plan view of an example of a security element that does not belong to the present invention; Figure 2b is a plan view of another example of a single magnetic element of a security element that does not belong to the present invention; Figure 2c is a plan view of an embodiment of a single magnetic element of a security element according to the present invention; Figure 2d is a cross-sectional view taken along the plane B-B' of the magnetic element of Figure 2c; Figure 2e is a cross-sectional view taken along the plane A-A' of the magnetic element of Figure 2c; Figure 3a is a plan view of the magnetic element of Figure 2c; Figure 3b is a cross-sectional view taken along the plane B-B' of the magnetic element of Figure 3a in which a possible encoding of the different areas is indicated; Figure 3c is a cross-sectional view taken along the plane A-A' of the magnetic element of Figure 3a in which a possible encoding of the different areas is indicated; Figure 3d shows the magnetic signal generated by the magnetic element of Figure 3a when this is brought to complete magnetic saturation and when read along a longitudinal direction; Figure 3e shows the magnetic signal that is obtained from the magnetic element of Figure 3a by converging the signals generated by the two rows of areas and when read along a longitudinal direction; Figure 4a is a plan view of another possible embodiment of a single magnetic element of a security element according to the present invention; Figure 4b is a cross-sectional view taken along the plane B-B' of the magnetic element of Figure 4a in which a possible encoding of the different areas is indicated; Figure 4c is a cross-sectional view taken along the plane A-A' of the magnetic element of Figure 4a in which a possible encoding of the different areas is indicated; Figure 4d shows the magnetic signal generated by the magnetic element of Figure 4a when this is brought to complete magnetic saturation and when read along a longitudinal direction; Figure 4e shows the magnetic signal that is obtained from the magnetic element of Figure 3a by converging the signals generated by the two rows of areas and when read along a longitudinal direction; Figure 5a shows a plan view of the magnetic element of Figure 2c; Figure 5b shows the magnetic signal generated by the magnetic element of Figure 5a when this is brought to complete magnetic saturation and when read along a transverse direction; Figure 5c shows the magnetic signal that is obtained from the magnetic element of Figure 5a by converging the signals generated by the two rows of areas when only some areas are magnetized and when it is read along a transverse direction; Figure 6 is a schematic diagram of a currency paper that comprises a security element according to the present invention.

[0026] With reference to the figures, the security element for currency papers 90 or documents or the like, generally designated by the reference numeral 1, comprises at least one magnetic element 2, 2', 2" which can be at least partially magnetized.

[0027] The security element 1 is therefore adapted to be inserted into a currency paper 90 (for example a banknote) or into a security document (for example a passport or other identity document) or into any other document or medium that requires a security check in order to verify its authenticity.

[0028] The at least one magnetic element 2, 2', 2" is magnetic in the sense that can be magnetized so as to attribute an encoding thereto; in other words it is configured to be magnetically encoded, so that the encoding can be read by passing a magnetic detection element along a reading axis.

[0029] In the simplest examples, not belonging to the claimed invention, the security element 1 consists of only the magnetic element 2, 2', 2" optionally fixed on a medium; or the security element 1 comprises a single magnetic element 2, 2', 2" optionally associated with other, conventional elements.

[0030] In other non-claimed examples, like the one shown in Figure 2a, the security element comprises a plurality of magnetic elements 2, 2', 2", each one of which can be provided according to any of the possible variants that will be described below, optionally fixed on a medium (for example a plastic substrate).

[0031] In some embodiments the security element 1 is a security thread (of any type that can be used for the purpose, for example holographic, varying in color, or with movement effects) or a holographic sheet in the form of strips or patches.

[0032] Optionally, in addition to the one or more magnetic elements 2, 2', 2" provided according to the invention, in the security element 1 there can be one or more conventional magnetic elements or other conventional encoded or identification elements.

[0033] Preferably, in the embodiments in which there is a plurality of magnetic elements 2, 2', 2", these are aligned along a longitudinal axis and are separated by non-magnetic spaces or zones 8.

[0034] These non-magnetic spaces or zones 8 can be used, for example, to introduce negative micro-tests as an additional anti-counterfeiting measure.

[0035] According to one non-claimed example of security element, the magnetic element 2, 2', 2" comprises a plurality of adjacent areas 4, 5 which are in mutual contact and are arranged side by side along at least one first longitudinal axis Y so as to form at least one row 6, 6a, 6b which is arranged along such longitudinal axis Y which corresponds to a preferred reading axis.

[0036] These areas 4, 5 comprise low-coercivity areas 5 and high-coercivity areas 4, and more precisely: at least one low-coercivity area 5 which has a first magnetic coercivity (preferably comprised between 150 Oe and 1500 Oe), at least one high-coercivity area 4 which has a second magnetic coercivity (preferably comprised between 1501 Oe and 5000 Oe) which is higher than the first magnetic coercivity.

[0037] As is known, coercivity is the capacity of a magnetic material to maintain its magnetization when it is exposed to a magnetic field of the opposite polarity, and more precisely the coercivity of a material is the intensity of the reverse magnetic field that it is necessary to apply to that material in order to demagnetize it after it has reached its saturation value. Therefore, for convenience, in the present description and in the accompanying claims the coercivity values of the materials are expressed in terms of intensity of the magnetic field (and therefore in Oested (Oe)) necessary to demagnetize the material after it has reached its saturation value.

[0038] In substance, the high-coercivity areas 4 and low-coercivity areas 5 are portions of the magnetic element 2, 2', 2" that are made of different materials (the high-coercivity zones 4 from a higher-coercivity material and the low-coercivity zones 5 from a lower-coercivity material).

[0039] In some variants, the high-coercivity areas 4 and the low-coercivity areas 5 are formed by a magnetic ink and preferably: the low-coercivity areas 5 are formed by a magnetic ink that comprises pigments that have a coercivity equal to the above mentioned first magnetic coercivity, and the high-coercivity areas 4 are formed by a magnetic ink that comprises pigments that have a coercivity value equal to the above mentioned second magnetic coercivity.

[0040] In some non-claimed examples, like that shown in Figure 2b, the magnetic element 2 comprises, and preferably consists of, a single row 6 of high-coercivity areas 4 and low-coercivity areas 5 that can be alternated in any sequence, according to the encoding that it is desired to obtain. In these embodiments the sole reading axis coincides with the longitudinal axis along which the areas 4, 5 are aligned.

[0041] According to some embodiments of the invention, like those shown in Figures 2c, 3a, 4a, 5a, the magnetic element 2', 2" comprises, and preferably consists of, two rows 6a, 6b of high-coercivity areas 4 and low-coercivity areas 5. Embodiments are also possible in which the magnetic element comprises three or more rows 6a, 6b of areas 4, 5 arranged side by side.

[0042] In practice, in these embodiments of the magnetic element 2', 2", the areas 4, 5 are arranged side by side along at least two rows 6a, 6b: a first row 6a along a first longitudinal axis Y and a second row 6b along a second longitudinal axis X which is parallel to the first longitudinal axis Y.

[0043] As is clear from Figures 3a, 4a and 5a, these two rows 6a, 6b are adjacent and are in mutual contact, so as to form a two-dimensional array of low-coercivity areas 5 and high-coercivity areas 4 that comprises rows 6a, 6b and columns (the latter formed by pairs of areas 4, 5 arranged side by side) which are arranged on a plane or in any case along a two-dimensional surface.

[0044] In the examples shown in Figures 2c, 3a, 4a, 5a, each magnetic element 2', 2" is formed by an array of dimensions 8x2 (two rows of eight areas 4, 5 each) of high-coercivity areas 4 and low-coercivity areas 5 that can be alternated in any sequence, according to the encoding that it is desired to obtain.

[0045] In practice, in these embodiments, each area 4, 5 is adjacent to, and in contact with, at least two other areas 4, 5, along two different non-opposing sides.

[0046] In general, according to the invention, each magnetic element 2, 2', 2" can be formed by an array LxC where L is the number of areas 4, 5 in each row and C is the number of rows arranged side by side; in the preferred embodiments each magnetic element 2, 2', 2" is formed by an array Lx2 or LX1 with L having any value.

[0047] According to the invention, as shown in Figure 3a, at least one of the low-coercivity areas 5 comprised in the first row 6a is arranged side by side, along a transverse axis Z which is perpendicular to the first longitudinal axis Y and to the second longitudinal axis X, with another low-coercivity area 5 which is comprised in the second row 6b so as to form a column (in this case a pair) of low-coercivity areas 5.

[0048] Optionally, as an alternative or in addition, as also shown in Figure 4a, at least one of the high-coercivity areas 4 comprised in the first row 6a is arranged side by side, along a transverse axis Z' which is perpendicular to the first longitudinal axis Y and to the second longitudinal axis X, with another high-coercivity area 4 which is comprised in the second row 6b so as to form a column (in this case a pair) of high-coercivity area 4.

[0049] Again for example, as shown in Figure 3a, it is possible for at least one of the low-coercivity areas 5 comprised in the first row 6a to be arranged side by side, along a transverse axis J which is perpendicular to the first longitudinal axis Y and to the second longitudinal axis X, with a high-coercivity area 4 which is comprised in the second row 6b so as to form a mixed column (in this case a pair) of high-coercivity areas 4 and low-coercivity areas 5.

[0050] It should be noted that the high-coercivity areas 4 and low-coercivity areas 5 are never superimposed, as they are arranged side by side along a two-dimensional surface.

[0051] Preferably, each magnetic element 2, 2', 2" is magnetized so that the high-coercivity areas 4 have a first magnetization value and the low-coercivity areas 5 have a magnetization value which is preferably nil or in any case lower than the first magnetization value.

[0052] In this manner it is possible to associate a bit value (a binary value equal to 0 or 1) with each area, as shown in Figures 3b, 3c, 4b, 4c, which can be read using a magnetic detection device (for example a magneto-inductive head).

[0053] In practice, by reading each magnetic element 2, 2', 2" along a reading axis which is parallel to the longitudinal axes X, Y, it is possible to obtain signals m1, m2, m3, m4 such as for example shown in Figures 3d, 3e, 4d, 4e.

[0054] According to the invention, the magnetization of the magnetic element 2', 2" can be read on two levels simultaneously (i.e. at each one of the two rows 6a, 6b, respectively along the first longitudinal axis X and the second longitudinal axis Y) and the readings on the two levels can be combined in order to produce a compound signal m1, m2 m3, m4 that depends on the magnetization of both the lines, thus obtaining an encoding that is more complex and therefore more secure.

[0055] In more detail, with reference to Figures 3a-3e, different encodings can be obtained on two different positions such as, for example, at the cross-section A-A' along the first longitudinal axis X (Figure 3c) and at the cross-section B-B' along the second longitudinal axis Y (Figure 3b), or, by converging the two signals, a third encoding can be obtained that produces the signal m2 of Figure 3e. Furthermore, with the magnetic element 2' brought to complete magnetic saturation, a fourth signal m1 (Figure 3d) can further be generated.

[0056] Figures 4a-4e show another variation of a magnetic element 2" that has high-coercivity areas 4 and low-coercivity areas 5 from which two different encodings can be obtained: one on the cross-section A-A' along the first longitudinal axis X (Figure 4c) and one on the cross-section B-B' along the second longitudinal axis Y (Figure 4b). Furthermore, with the complete saturation of the magnetic element 2" a signal m3 is obtained as indicated in Figure 4d. By converging the two signals deriving from the reading along the cross-sections A-A' and B-B' (i.e. along the two longitudinal axes X and Y) a signal m4 (Figure 4e) is obtained along with a corresponding multilevel encoding, thus increasing the security over a binary system.

[0057] In this manner, for example, if only the high-coercivity areas 4 are magnetized, the simultaneous correspondence of two high-coercivity areas 4 on the two reading positions can generate a more intense overall magnetic signal than the case where a high-coercivity area 4 is present on only one position, and therefore the magnitude of the signals generated can also be evaluated, as shown in Figure 4e.

[0058] In addition, in the embodiments where the magnetic element 2', 2" comprises at least two rows 6a, 6b, it is possible to carry out a reading along a reading axis that is transverse (therefore perpendicular to the longitudinal axes X, Y).

[0059] For example Figures 5a-5c show a magnetic element 2' (Figure 5a) and the corresponding magnetic signals m6, m7 that result from a transverse reading of that magnetic element 2', if the high-coercivity areas 4 and low-coercivity areas 5 (Figure 5b) are completely saturated, or if only the high-coercivity areas 4 (Figure 5c) are magnetized so as to obtain a signal m7 that derives only from these.

[0060] In this manner, even in the eventuality of a transverse reading, the level of analysis required is increased, and with it the resistance to counterfeiting.

[0061] Embodiments are also possible (not shown) in which the magnetic element 2', 2" comprises two rows 6a, 6b and one of these is made up only of high-coercivity areas 4 or only of low-coercivity areas 5, in practice therefore one of the rows 6a, 6b being constituted by a single area of uniform coercivity.

[0062] In order to be able to discriminate between the areas 5, 4 of different coercivity within the magnetic element 2, 2', 2" it is necessary to subject the magnetic element 2, 2', 2" itself to different magnetization fields so as to be able to carry out readings under different magnetization conditions.

[0063] Comparison of the signals collected makes it possible, with an adapted recognition algorithm, to verify the authenticity of the document or currency paper 90 into which the security element 1 is inserted.

[0064] For example, as shown in Figure 3, if the magnetic element 2' is subjected to a first magnetic field (for example of 10,000 Oe) then all the areas 4, 5 that make up that magnetic element 2' will be saturated, both the low-coercivity areas 5 and the high-coercivity areas 4, as a consequence acquiring an overall signal m2 as indicated in Figure 3d.

[0065] Subsequently, if the same magnetic element 2' is subjected to a second magnetic field of lower intensity than the first and more precisely of lower intensity than the coercivity of the high-coercivity areas but higher intensity than the coercivity of the low-coercivity areas (for example 1,500 Oe), and which therefore succeeds in rotating the magnetic field only of the low-coercivity areas 5, subsequent acquisition of a signal in the new state of magnetization will obtain an overall signal as indicated in Figure 3e.

[0066] The method for providing a security element 1 according to the invention is defined in claim 7 and comprises a step of construction of at least one magnetic element 2, 2', 2" which can be at least partially magnetized and a step of encoding which is obtained by magnetizing at least partially this magnetic element 2, 2', 2".

[0067] According to the invention, the step of construction of the magnetic element 2, 2', 2" entails forming a plurality of adjacent areas 4, 5 which are in contact with each other and are arranged side by side along at least one first longitudinal axis Y so as to form at least one row 6, 6a, 6b.

[0068] As described above, these areas 4, 5 comprise: at least one low-coercivity area 5 which has a first magnetic coercivity, and at least one high-coercivity area 4 which has a second magnetic coercivity which is higher than the first magnetic coercivity.

[0069] Preferably, as previously mentioned, the step of encoding comprises the steps of: a) subjecting the magnetic element 2, 2', 2" to a magnetic field which has an intensity which is higher than the second magnetic coercivity, so as to magnetize to saturation both the low-coercivity areas 5 and the high-coercivity areas 4, and then b) subjecting the magnetic element 2, 2', 2" to a magnetic field that has an (opposing) intensity comprised between the first magnetic coercivity and the second magnetic coercivity, so as to cancel out the magnetization only of the low-coercivity areas 5.

[0070] Operation of the security element 1 is clear and evident from the foregoing description.

[0071] In substance, after having magnetized (and therefore encoded) the at least one magnetic element 2, and after having inserted it into the document or currency paper 90, it is possible to decode or read the magnetic code by means of the translation of a magnetic sensor over the security element 1, or conversely, along a reading axis, in so doing reading a signal m1-m7.

[0072] Such signal m1-m7 can be compared with a series of acceptance parameters in order to judge the authenticity of the document.

[0073] Furthermore, the method according to the present invention can comprise direct printing of the security element on the document, with rotogravure, intaglio and screen printing techniques, or by way of transfer from a backing.

[0074] In practice, the security element 1 can advantageously be provided directly on the security document (or currency paper) by means of a printing method, preferably intaglio, screen or offset printing, or by transfer.

[0075] The present invention also relates to any document or currency paper 90 that comprises one or more security elements 1 of the type just described.

[0076] In practice it has been found that the security element for currency papers or documents or the like, according to the present invention, achieves the intended aim and objects in that it is capable of guaranteeing a greater level of security, since the encoding that can be obtained represents a formidable barrier against the counterfeiting of this security element.

[0077] Another advantage of the security element, according to the invention, consists in that it enables encodings that are more complex or in any case harder to counterfeit.

[0078] Another advantage of the security element, according to the invention, consists in that it is easy to implement and economically competitive when compared to the known art.

[0079] Furthermore, the present invention provides a valid alternative to the background art.

[0080] The security element for currency papers or documents or the like thus conceived is susceptible of numerous modifications and variations all of which are within the scope of the appended claims.

[0081] Moreover, all the details may be substituted by other, technically equivalent elements.

[0082] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims.

Claims

1. A security element (1) for currency papers (90) or documents or the like, which comprises at least one magnetic element (2, 2') which can be at least partially magnetized, said magnetic element (2, 2') comprising a plurality of adjacent areas (4, 5) which are in mutual contact and are arranged side by side along at least one first longitudinal axis (Y) so as to form at least one row (6, 6a, 6b), said areas (4, 5) comprising: - at least one low-coercivity area (5) which has a first magnetic coercivity, and - at least one high-coercivity area (4) which has a second magnetic coercivity which is higher than said first magnetic coercivity, wherein said areas (4, 5) are arranged side by side along at least two rows (6a, 6b), a first row (6a) along a first longitudinal axis (Y) and a second row (6b) along a second longitudinal axis (X) which is parallel to said first longitudinal axis (Y), said two rows (6a, 6b) being adjacent, characterised in that: said two rows are in mutual contact, and in that, in said magnetic element (2', 2"): at least one of said low-coercivity areas (5) comprised in said first row (6a) is arranged side by side, along a transverse axis (Z) which is perpendicular to said first longitudinal axis (Y) and to said second longitudinal axis (X), with another low-coercivity area (5) which is comprised in said second row (6b) so as to form a column of low-coercivity area (5), and / or at least one of said high-coercivity areas (4) comprised in said first row (6a) is arranged side by side, along a transverse axis (Z') which is perpendicular to said first longitudinal axis (Y) and to said second longitudinal axis (X), with another high-coercivity area (4) which is comprised in said second row (6b) so as to form a column of high-coercivity area (4).

2. The security element (1) according to claim 1, characterized in that, in said magnetic element (2', 2"), at least one of said low-coercivity areas (5) comprised in said first row (6a) is arranged side by side, along a transverse axis (J) which is perpendicular to said first longitudinal axis (Y) and to said second longitudinal axis (X), with a high-coercivity area (4) which is comprised in said second row (6b) so as to form a mixed column of high-coercivity area (4) and low-coercivity area (5).

3. The security element according to one or more of the preceding claims, characterized in that said first magnetic coercivity is comprised between 150 Oe and 1500 Oe and said second magnetic coercivity is comprised between 1501 Oe and 5000 Oe.

4. The security element (1) according to one or more of the preceding claims, characterized in that: said low-coercivity areas (5) are formed by a magnetic ink that comprises pigments that have said first magnetic coercivity, and said high-coercivity areas (4) are formed by a magnetic ink that comprises pigments that have said second magnetic coercivity.

5. The security element (1) according to one or more of the preceding claims, characterized in that said high-coercivity areas (4) have a first magnetization value and said low-coercivity areas (5) have a magnetization value which is nil or lower than said first magnetization value.

6. The security element (1) according to one or more of the preceding claims, characterized in that it is provided directly on the security document by means of printing methods such as intaglio printing, screen printing, offset printing, or by transfer.

7. A method for providing a security element (1) for currency papers (90) or documents or the like, which comprises a step of construction of a magnetic element (2, 2', 2") which can be at least partially magnetized and a step of encoding which is obtained by magnetizing at least partially said magnetic element (2, 2', 2"), said step of construction of the magnetic element (2, 2', 2") comprising the step of forming a plurality of adjacent areas (4, 5) which are in contact with each other and are arranged side by side along at least one first longitudinal axis (Y) so as to form at least one row (6, 6a, 6b), said areas (4, 5) comprising: - at least one low-coercivity area (5) which has a first magnetic coercivity, and - at least one high-coercivity area (4) which has a second magnetic coercivity which is higher than said first magnetic coercivity, wherein said areas (4, 5) are arranged side by side along at least two rows (6a, 6b), a first row (6a) along a first longitudinal axis (Y) and a second row (6b) along a second longitudinal axis (X) which is parallel to said first longitudinal axis (Y), said two rows (6a, 6b) being adjacent, characterised in that said two rows are in mutual contact, and in that, in said magnetic element (2', 2"): at least one of said low-coercivity areas (5) comprised in said first row (6a) is arranged side by side, along a transverse axis (Z) which is perpendicular to said first longitudinal axis (Y) and to said second longitudinal axis (X), with another low-coercivity area (5) which is comprised in said second row (6b) so as to form a column of low-coercivity area (5), and / or at least one of said high-coercivity areas (4) comprised in said first row (6a) is arranged side by side, along a transverse axis (Z') which is perpendicular to said first longitudinal axis (Y) and to said second longitudinal axis (X), with another high-coercivity area (4) which is comprised in said second row (6b) so as to form a column of high-coercivity area (4).

8. The method according to claim 7, characterized in that said step of encoding comprises the steps of: a) subjecting the magnetic element (2, 2', 2") to a magnetic field which has an intensity which is higher than said second magnetic coercivity, so as to magnetize to saturation both the low-coercivity areas (5) and the high-coercivity areas (4), and then b) subjecting said magnetic element (2, 2', 2") to a magnetic field that has an intensity comprised between said first magnetic coercivity and said second magnetic coercivity, so as to cancel out the magnetization only of said low-coercivity areas (5).

9. The method according to claim 7 or 8, characterized in that said security element (1) is provided directly on a document or currency paper (90) by means of a printing method, preferably intaglio printing or screen printing or offset printing, or by transfer.

10. A document or currency paper (90), characterized in that it comprises one or more security elements (1) according to one or more of claims 1 to 6.

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