A security inlay for a security document field of

Abstract

The present invention relates to a security inlay for a security document, such as an RFID-enabled security document, the security inlay comprising: an inlay substrate; an antenna provided in or on the inlay substrate and configured to communicate with a reader; a chip module integrated into the inlay substrate and coupled to the antenna; and at least one security feature configured to burn in one or more portions, when exposed to microwave radiations, so as to identify a security status of the security inlay, for example a disabled status. The present invention also relates to the security document, such as an RFID-enabled security document, comprising one or more of such security inlays and to the method for authenticating such security document.

Description

[0001] A security inlay for a security document

[0002] Field of the invention

[0003] The present invention relates to a security inlay, a security document, and a method for authenticating a security document.

[0004] Technical background

[0005] In the field of security documents, there are presently various different types of security documents, such as smart cards (bank cards, electronic identity cards, key cards, etc.), a datapage of an identity document booklet (e.g., an electronic passport), and the like. These security documents include an electronic circuit for enabling contact and / or contactless communication with an electronic module of the security document so as to store on and / or retrieve electronic data from the electronic module of the security document.

[0006] Security documents may advantageously exploit the Radio Frequency Identification Device (RFID) technology and may comprise a chip, which stores information about the item, and an antenna, which receives and transmits data to the reader. For example, E-Passports (Electronic Passports) typically include an embedded RFID chip that stores personal and biometric data of the passport holder, such as name, date of birth, and other personal details, a digital photograph, fingerprints or iris scans, and / or a digital signature to verify the authenticity of the passport.

[0007] E-passports and other RFID-enabled security documents use protocols, like the Extended Control Access (EAC) protocol, to protect sensitive data stored on the RFID chip. The EAC, for example, ensures that only authorized entities (e.g., border control authorities) can access sensitive biometric data, such as fingerprints or iris scans.

[0008] However, forgery attempts have been reported, such as attempts to manipulate, clone, or tamper the data or processes associated with the RFID chips of the security documents. For example, RFID-enabled security documents may be positioned in a microwave oven and then irradiated with microwaves for a short time interval, in order to disable the RFID chip without physically damaging the document.

[0009] Forgery of RFID-enabled security documents highlights vulnerabilities in the personalization, encryption, or verification stages of same. Modern e-passport systems aim to mitigate these risks through strong cryptographic protocols, strict manufacturing processes, and layered security mechanisms. However, as attackers develop new techniques, ongoing vigilance and technological updates remain critical. In view of the above-described situation, it is desirable to increase the security level of RFID- enabled security documents by providing additional security features that can be used as permanent markers in the event of tampering. Furthermore, it is desirable to allow authentication of an RFID-enabled security document.

[0010] Summary of the invention

[0011] The above described problems and objects are solved in various aspects of the present disclosure by means of a security inlay, a security document, and a method for authenticating the security document as defined in the enclosed set of claims.

[0012] According to a first aspect of the present invention, a security inlay for a security document is provided, the security inlay comprising: an inlay substrate; an antenna provided in or on the inlay substrate and configured to communicate with a reader; a chip module integrated into the inlay substrate and coupled to the antenna; and at least one security feature configured to burn in one or more portions, when exposed to microwave radiations, so as to identify a security status of the security inlay, for example a disabled status or a status indicating a tampering attempt.

[0013] The advantage of this configuration is that the security inlay of the present invention can reveal a tampering attempt due to the presence of at least one security feature. In fact, if the security inlay is exposed to microwave radiation in order to disable the chip module (for example to prevent access to the biometric features stored in the chip module), the security feature will burn in one or more portions and these burnt portions will remain visible on the security inlay. Therefore, an inspector will be able to identify the one or more burnt portions on the security feature and determine a potential tampering of the security inlay.

[0014] The security feature is advantageously designed so as to burn in one or more portions, after exposure to microwave radiations, in a time interval this is equal to or shorter than the time interval necessary for the chip module to burn and to be disabled. Preferably, the security feature is designed to burn in less than 3 seconds, even more preferably, less than 2 seconds. The security feature is advantageously designed so as to burn in one or more portions, after exposure to microwave radiations, regardless of the orientation of the incident microwave radiations.

[0015] The inventors found that a main physical parameter that governs the heating and burning of the security feature is the degree of which the security feature absorbs the energy of the electromagnetic field of the radiations. The energy of the electromagnetic field generates an electrical current which flows through the security feature (which can be approximated as a circuit). The heat generated is dependent on the resistance, according to the Joule law P=Rxl2. Therefore, the part in the circuit with the highest resistance will burn first: this part is usually the part of the circuit that bonds the wire to the chip module or the adhesive connection between the module substrate and the chip.

[0016] Several strategies can be followed to increase the heating speed of the security feature.

[0017] One option is to design the security feature so as to have a resonance frequency of 2.4GHz, which corresponds to the operational frequency of the microwave oven of 2.4 GHz. In this way, more energy can be absorbed in the same time interval.

[0018] Another option is to increase the resistance of the security feature by adapting the material. For example, the resistance of the aluminum is approximately equal to three times the resistance of copper, hence, by making the wire of the security feature of aluminum, three times more heat can be generated with respect to a wire of a security feature made of copper.

[0019] Another option is to increase the resistance of the security feature by decreasing the cross- sectional area of the wire of the security feature. In fact, the resistance of a wire is inversely proportional to its cross-sectional area.

[0020] According to preferred embodiments, the chip module may store biometric features of a user, for example biometric features of the owner of the security document.

[0021] According to preferred embodiments, the security inlay may comprise a single security feature.

[0022] According to other preferred embodiments, the security inlay may comprise a plurality of security features, such as two, three, or more.

[0023] According to preferred examples, the antenna may be an etched antenna or a wire-embedded antenna.

[0024] According to preferred embodiments of the first aspect of the invention, a security inlay is provided, wherein the security feature comprises an electromagnetic resonator wire made of conductive material, such as copper, or an alloy of copper-nickel. In the present disclosure, it is to be understood that an “electromagnetic resonator wire” indicates a wire designed to resonate at specific frequencies, when subjected to oscillatory or wave-like excitation, and to support electromagnetic standing waves.

[0025] The advantage of this configuration is that, when the frequency of the external electromagnetic waves, such as microwaves, matches the resonant frequency of the electromagnetic resonator wire, the latter can efficiently absorb energy. By maximizing the energy absorbed by the resonator wire, it is possible to maximize its response to microwaves irradiation and to maximize formation of burnt portions. In this way, an inspector can easily and efficiently detect the presence of the burnt portions on the resonator wire and determine a possible tampering attempt of the security inlay.

[0026] The electromagnetic resonator wire is configured to burn in one or more portions after exposure to microwave radiations and these one or more burnt portions may be positioned anywhere along the length of the resonator wire, for instance at one or two ends, and / or along the entire length of the resonator wire, depending on the physical parameters of the microwave radiations and the physical properties of the wire (such as length and material).

[0027] The security feature may comprise a single wire ora plurality of wires defining a predefined shape, for example two wires intersecting each other.

[0028] The shape and orientation of the security feature affect the polarization of the excited electromagnetic wave after exposure to the external electro-magnetic field. If the polarization of the excited wave matches the orientation of the security feature, energy absorption is maximized and burning spots can easily be generated.

[0029] According to preferred embodiments, the resonator wire may be a straight wire.

[0030] The advantage of this configuration is that the resonator wire having a straight shape will burn in one or more portions, after exposure to microwave radiations, regardless of the orientation of the incident microwave radiations and / or of the position of the security inlay inside a microwave oven and / or the power of the microwave oven. The straight wire can fully absorb the energy of the external electromagnetic field in one direction, i.e. parallel to its extension direction. In this way, in the event of a tampering action of the chip module by exposure to microwaves radiation in a microwave oven, a tampering mark will remain in the security inlay, due to the one or more burnt portions in the straight wire. Preferably, the one or more burnt portions may cover the entire straight wire. According to preferred embodiments, the resonator wire may comprise one or more wire segments connected to each other and defining an angle equal to or larger than 90°, for example, one or more wire segments having an L-shape.

[0031] The advantage of this configuration is that energy absorption is maximized along two directions, i.e. the two directions parallel to the two segments forming the resonator wire. Therefore, the probability of formation of the burning spots is increased, even if the polarization of the incident radiation and the orientation of the security inlay with respect to the incident radiation are not known.

[0032] According to preferred embodiments, the resonator wire may comprise one or more wires intersecting each other to define a cross-shape.

[0033] This configuration is advantageous because, at the crossing point, the two wires are close to each other, hence the energy absorption is maximized and the probability of formation of a burning spot is increased. Moreover, a burning spot in correspondence of the crossing point is easily visible.

[0034] According to preferred embodiments, the resonator wire may have a loop-shape.

[0035] This configuration is advantageous because, at the intersection point of the loop, the two wires are close to each other, hence the energy absorption is maximized and the probability of formation of a burning spot is increased. Moreover, a burning spot in correspondence of the intersection point is easily visible.

[0036] Moreover, the resonator wire having a loop-shape will burn in one or more portions, after exposure to microwave radiations, regardless of the orientation of the incident microwave radiations. In this way, in the event of a tampering action of the chip module by exposure to microwaves radiation in a microwave oven, a tampering mark will remain in the security inlay, due to the one or more burnt portions in the loop wire. Preferably, the one or more burnt portions may cover the entire loop-shaped wire.

[0037] According to preferred embodiments, the resonator wire may have the shape of an open polygon, for example an open square.

[0038] In the present disclosure, it is to be understood that an “open polygon” indicates a polygon, for example, a square, wherein two sides are not connected to each other so that the perimeter of the polygon defines an open polyline. The advantage of this configuration is that it can be easily implemented in case of copper tape etching, or conductive screen printing.

[0039] According to preferred embodiments, the resonator wire may have the shape of a meander structure, wherein the meander structure comprises a plurality of segments defining angles of 90° with each other and wherein the segments may overlap or not overlap one another.

[0040] The advantage of this configuration is that burning of the resonator wire having a meander structure can be obtained in a short time interval after exposure to microwave radiations.

[0041] The configuration with overlapping segments is advantageous because, at the overlapping point, the two wire segments are close to each other, hence the energy absorption is maximized and the probability of formation of a burning spot is increased. Moreover, a burning spot in correspondence of the overlapping point is easily visible.

[0042] According to preferred embodiments of the first aspect of the invention, a security inlay is provided, wherein the resonator wire has a length comprised between 25 mm and 70 mm, more preferably between 35 and 50 mm, even more preferably equal to 48 mm.

[0043] These configurations have the advantage to maximize energy absorption by the resonator wire, when the resonator wire is exposed to microwaves irradiation is a microwave oven, and to maximize formation of burnt portions. At resonance, in fact, standing waves of electromagnetic energy are established within the resonator wire. The electric and magnetic field patterns inside the resonator wire correspond to the modes of resonance, concentrating energy in specific regions. The length of the resonator wire is thus advantageously designed to resonate at the working frequency of a microwave oven, for example at the working frequency of 2.45 GHz, so as to maximize the probability of the formation of burnt portions in correspondence of those specific regions. In this way, an inspector can easily and efficiently detect the presence of the burnt portions on the resonator wire and determine a possible tampering attempt of the security inlay by irradiation of the security inlay in a microwave oven.

[0044] It should be understood that, if the resonator wire has the shape of a straight wire, the length of the straight wire is preferably comprised between 25 mm and 70 mm, more preferably between 35 and 50 mm, even more preferably equal to 48 mm.

[0045] On the other hand, if the resonator wire has an L-shape, a loop shape, a cross-shape, an open polygon-shape, a meander structure, or the like, it should be understood that the area where the resonator wire is placed preferably has a dimension comprised between 25 mm and 70 mm, more preferably between 35 and 50 mm, even more preferably equal to 48 mm. For example, a circle area including the resonator wire preferably has a diameter comprised between 25 mm and 70 mm, more preferably between 35 and 50 mm, even more preferably equal to 48 mm.

[0046] According to preferred embodiments of the first aspect of the invention, a security inlay is provided, wherein the material of the antenna has a first conductivity and the material of the security feature, such as the resonator wire, has a second conductivity, and the second conductivity is lower than the first conductivity.

[0047] Preferably, the security feature is made of aluminium (conductivity: 2.82 x10'8Qm at 20°) and / or copper (conductivity: 1.68 x10'8Qm at 20°).

[0048] According to preferred embodiments of the first aspect of the invention, a security inlay is provided, wherein the security feature, such as the resonator wire, is embedded in a dielectric material having a relative permittivity equal to or larger than 2, for example equal to 2 or 3.

[0049] Preferably, the dielectric material is PVC, Epoxy glass, PC and / or glass. These materials are advantageous because they are characterized by a high permittivity, which leads to higher polarization resulting in higher electrical fields and thus more current.

[0050] The advantage of this configuration is that the security feature is insulated from other electronic components. Moreover, the security feature may have a shape with overlapping portions, without formation of short circuits in the wire itself.

[0051] According to preferred embodiments of the first aspect of the invention, a security inlay is provided, wherein the security feature is electrically coupled to the antenna.

[0052] The advantage of this configuration is that, to ensure electrical coupling between the security feature and the antenna, the security feature should be positioned in the vicinity of the antenna. In this way, energy absorption of the security feature is accelerated. Therefore, in the configuration with the security feature optimally electrically coupled to the antenna, the security feature can easily burn and the burning signs can be easily detected.

[0053] According to preferred embodiments of the first aspect of the invention, a security inlay is provided, wherein the security feature is electrically connected to the antenna.

[0054] The advantage of this configuration is that the electrical connection between the security feature and the antenna increases the power absorption of the security feature. Therefore, the security feature can burn fast and the burning signs can be easily detected. According to preferred embodiments of the first aspect of the invention, a security inlay is provided, wherein the security feature is physically separated from the antenna.

[0055] The advantage of this configuration is that, in the region physically separating the security feature and the antenna, the burning signs can be easily detected.

[0056] In the present disclosure, the expression “the security feature is physically separated from the antenna” indicates that they do not have any parts or components, such as electronic components, in common and they are not electrically connected.

[0057] According to preferred embodiments of the first aspect of the invention, a security inlay is provided, wherein the security feature is positioned within a perimeter defined by the antenna.

[0058] The advantage of this configuration is that it can be easily implemented in security documents having a standard ID1 size.

[0059] According to preferred embodiments of the first aspect of the invention, a security inlay is provided, wherein the security feature is positioned outside a perimeter defined by the antenna.

[0060] The advantage of this configuration is that it can be easily implemented in security documents having a size larger than the standard ID1 size.

[0061] According to preferred embodiments of the first aspect of the invention, a security inlay is provided, which comprises two or more security features, wherein at least one security feature is positioned outside a perimeter defined by the antenna and at least one security feature is positioned within a perimeter defined by the antenna.

[0062] According to a second aspect of the present invention, a security document is provided, which comprises a security inlay as the ones disclosed above, and one or more overlays formed on at least one exposed surface of the security inlay.

[0063] The security document of the present invention is advantageously based on the security inlays disclosed above.

[0064] According to preferred embodiments, the security document may be a smart card, an electronic identity booklet, or a datapage of an electronic booklet.

[0065] According to preferred embodiments, the antenna may be an RFID antenna and the security document may be an RFID-enabled security document. According to a third aspect of the present invention, a method for authenticating a security document as the ones disclosed above is provided, wherein the method comprises the following steps:

[0066] (a) subjecting the security document to a visual inspection procedure to determine a burning status of the security feature; and

[0067] (b) determining an authentication status of the security document on the basis of the burning status of the security feature.

[0068] This method may be advantageously carried out to establish if a security document has been tampered or counterfeited, for instance by disabling the chip module and preventing access to the biometric data stored therein.

[0069] Preferably, the visual inspection is carried out by an operator by eye, without the need of any additional equipment, hence it is easy and simple to carry out.

[0070] Brief description of the drawings

[0071] Various illustrative embodiments and other advantages of the various aspects of the present disclosure will become apparent from the detailed description of the accompanying figures as presented below.

[0072] Fig. 1 schematically illustrates a top view of a security inlay for an RFID-enabled security document, according to an embodiment of the present invention;

[0073] Fig. 2 schematically illustrates a top view of a security inlay for an RFID-enabled security document, according to another embodiment of the present invention;

[0074] Fig. 3a schematically shows a security feature having a straight line-shape, according to preferred embodiments of the present invention;

[0075] Fig. 3b schematically shows a security feature having a loop-shape, according to preferred embodiments of the present invention;

[0076] Fig. 3c schematically shows a security feature having a cross-shape, according to preferred embodiments of the present invention;

[0077] Fig. 3d schematically shows a security feature having a shape of an open square, according to preferred embodiments of the present invention; Fig. 3e schematically shows security features comprising two segments that define an angle equal to or larger than 90°, according to preferred embodiments of the present invention;

[0078] Fig. 3f schematically shows security features having a meander structure, according to preferred embodiments of the present invention;

[0079] Fig. 4 schematically illustrates a top view of an RFID-enabled security document, according to an embodiment of the present invention;

[0080] Fig. 5a schematically illustrates a top view of a security feature comprising a burnt portion, according to an embodiment of the present invention;

[0081] Fig. 5b schematically illustrates a top view of a security feature comprising a burnt portion, according to another embodiment of the present invention.

[0082] The figures as accompanying the present disclosure are only provided for schematically showing some concepts of the present disclosure without showing all possible details of certain embodiments and without being actually to scale.

[0083] Detailed description

[0084] Referring to Fig. 1 , a security inlay 100 for a security document (not illustrated) is shown in a schematic top view. Examples of a security document may be a smart card or an electronic identity document or booklet, such as an electronic passport or elD, and the security inlay 1 is configured for integration into a smart card or an electronic identity document or booklet, such as an electronic passport or elD.

[0085] In the configuration shown in Fig. 1 , the security inlay 100 comprises an inlay substrate 110, an RFID antenna 120 provided in or on the inlay substrate 110, and a chip module 130 integrated into the inlay substrate 3 and electrically coupled to the antenna 120. The chip module 130 may be disposed on the inlay substrate 110 or accommodated into a recess (not illustrated) provided in the inlay substrate 110. The RFID antenna may be an etched antenna or a wire embedded antenna, or an antenna realized by means of any technology known at the state of the art.

[0086] With continued reference to Fig. 1 , the security inlay 100 further comprises an electromagnetic resonator wire 140, which provides an additional security feature to the security inlay 100. The resonator wire 140, in fact, is configured to burn in one or more portions (as schematically shown in Figs. 5a and 5b), when exposed to microwave radiations, so as to identify a security status of the security inlay 100, for example a status wherein the chip module 130 has been disabled. The resonator wire 140 of Fig. 1 is a wire of conductive material, for example of copper or aluminum.

[0087] With continued reference to Fig. 1 , the resonator wire 140 has the shape of a loop. The resonator wire 140 is advantageously designed to have a loop-shape in such a way that the resonator wire 140 can burn in one or more portions, if the security inlay 100 is exposed to microwave radiations, regardless of the orientation of the incident microwave radiations. In this way, in the event of a tampering action of the chip module 130 by exposure to microwaves radiation in a microwave oven, a tampering mark will remain in the security inlay, due to the one or more burnt portions in the loop wire (as described below).

[0088] The loop wire of the resonator wire 140 in Fig. 1 is embedded in a case of dielectric material, such as PVC or PC. In this way, there are no short circuits in correspondence with the center of the loop where the two wire portions overlap.

[0089] The resonator wire 140 of Fig. 1 is positioned on the inlay substrate 110 within a perimeter defined by the RFID antenna 120.

[0090] The resonator wire 140 of Fig. 1 is not electrically connected and is physically separated by the RFID antenna 120. The resonator wire 140 is advantageously electrically coupled to the RFID antenna 120.

[0091] It is to be understood that, even if reference is made, in the present detailed description, to an RFID antenna and an RFID-enabled security document, the present invention is not limited thereto, but it could be applied as well to other antennas and security documents using other communication technologies.

[0092] Fig. 2 schematically illustrates a top view of a security inlay 100, according to another embodiment of the present invention.

[0093] The security inlay 100 of Fig. 2 comprises the same components as the security inlay 100 of Fig. 1. In particular, the security inlay 100 of Fig. 2 comprises a resonator wire 140, which may be similar, in some aspects, to the resonator 140 of Fig. 1 , and which is configured to burn in one or more portions, when exposed to microwave radiations, thereby providing an additional security feature to the security inlay 100.

[0094] The resonator wire 140 of Fig. 2 is positioned on the inlay substrate 110 within a perimeter defined by the RFID antenna 120. Even if both Figs. 1 and 2 schematically show that the resonator wire 140 is positioned on the inlay substrate 110 within a perimeter defined by the RFID antenna 120, other configurations are also possible, wherein the resonator wire 140 may be positioned on the inlay substrate 110 outside a perimeter defined by the RFID antenna 120.

[0095] The resonator wire 140 of Fig. 2 is not electrically connected and is physically separated by the RFID antenna 120. The resonator wire 140 is advantageously electrically coupled to the RFID antenna 120.

[0096] Even if both Figs. 1 and 2 schematically show that the resonator wire is not electrically connected and is physically separated by the RFID antenna 120, other configurations are also possible, wherein the resonator wire 140 may be electrically connected to the RFID antenna 120.

[0097] The resonator wire 140 of Fig. 2 is configured as a straight wire. The advantage of this configuration is that the resonator wire having a straight shape can burn in one or more portions, after exposure to microwave radiations, regardless of the orientation of the incident microwave radiations and / or of the position of the security inlay inside a microwave oven and / or the power of the microwave oven. In this way, in the event of a tampering action of the chip module 130 by exposure to microwaves radiation in a microwave oven, a tampering mark will remain in the security inlay, due to the one or more burnt portions in the straight wire, as explained below.

[0098] The resonator wire 140 is not limited to the shapes or configurations shown in Figs. 1 and 2. Figs. 3a-3f schematically illustrate preferred shapes and configurations of resonator wires 140 that can be provided in the security inlays 100.

[0099] According to preferred embodiments, as shown in Fig. 1 and 3a, the resonator wire 141 may be a straight wire.

[0100] According to other preferred embodiments, as shown in Fig. 2 and 3b, the resonator wire 142 may be a looped wire.

[0101] According to other preferred embodiments, as shown in Fig. 3c, the resonator wire 143 may comprise two portions intersecting each other to form a cross-shaped wire.

[0102] According to other preferred embodiments, the resonator wire 140 may be designed as an open polyline defining the shape of an open polygon, such as the open square wire 144 of Fig. 3d.

[0103] According to preferred embodiments, as shown in Fig. 3e, the resonator wire 140 may comprise two wire segments connected to each other and defining an angle equal to or larger than 90°. For example, the resonator wire 145 of Fig. 3e comprises two wire portions connected to each other and defining an angle equal to 90°, so as to define an “L-shape”.

[0104] For example, each of the resonator wires 145’ of Fig. 3e comprises two portions connected to each other and defining an angle larger than 90°.

[0105] According to preferred embodiments shown in Fig. 3e, the security feature of the security inlay 100 may comprise two resonator wires 140 adjacent to each other so as to define a predefined pattern. For example, two L-shaped wires 145 may be placed next to each other as shown in Fig. 3e, either with the same orientation or with opposite orientations. For example, two angled wires 145’ may be placed next to each other, symmetrically with respect to a symmetry line parallel to one segment of each wire 145’.

[0106] According to preferred embodiments shown in Fig. 3f, the security feature of the security inlay 100 may comprise a resonator wire 146, 146’ having a meander-like structure.

[0107] The resonator wire 146 of Fig. 3f has a meander structure comprising eight segments of different lengths, wherein each segment forms an angle of 90° with the following one and the segments do not overlap with each other.

[0108] The resonator wire 146’ of Fig. 3f has a meander structure comprising eight segments of different lengths and an overlapping point, each segment forming an angle of 90° with the following one. When counting the segments in a counter-clockwise direction, in the resonator wire 146’ the last segment overlaps a portion of the third segment.

[0109] Each resonator wire 141 , 142, 144, 145, 145’, 146, and 146’ of Figs. 3a-3f preferably has a length or is positioned in an area having a dimension comprised between 25 mm and 70 mm, more preferably between 35 and 50 mm, even more preferably equal to 48 mm, so as to maximize energy absorption, when each resonator wire 141 , 142, 144, 145, 145’, 146, and 146’ is exposed to microwaves irradiation is a microwave oven, and to maximize formation of burnt portions. At resonance, in fact, standing waves of electromagnetic energy are established within the resonator wires 141 , 142, 144, 145, 145’, 146, and 146’. The electric and magnetic field patterns inside the resonator wires 141 , 142, 144, 145, 145’, 146, and 146’ correspond to the modes of resonance, concentrating energy in specific regions. The length and / or the dimension of the area of the resonator wire are thus advantageously designed to resonate at the working frequency of a microwave oven, for example at the working frequency of 2.45 GHz, so as to maximize the probability of the formation of burnt portions in correspondence of those specific regions, as explained below In particular, the inventors found out that, by designing the straight resonator wire 141 and the resonator wire 145 with an L-shape so that the length is 48 mm, the resonator wires 141 and 145 will completely burn after exposure to microwaves irradiation for 2 or 3 seconds, when placed in a microwave oven of the type RW800 having a working resonance frequency of 2.45 GHz and a power of 800 W.

[0110] Even if it is not shown in the figures, it is to be understood that the security inlay 100 may also comprise two or more resonator wires 140. The two or more resonator wires 140 may have the same shape or different shapes, for example, each resonator wire 140 may be configured as one of the resonators 141 , 142, 143, 144, 145, 145’, 146, and / or 146’ of Figs. 3a-3f. Moreover, the two or more resonator wires 140 may be both placed within a perimeter defined by the RFID antenna 120, or they may be both placed outside a perimeter defined by the RFID antenna 120; alternatively, at least one resonator wire 140 may be placed within a perimeter defined by the RFID antenna 120, and at least one resonator wire 140 may be placed outside a perimeter defined by the RFID antenna 120.

[0111] Referring to Fig. 4, a security document 200 is shown as an electronic identity booklet, e.g. an electronic passport. The security document 200 comprises a number of pages, which are schematically illustrated in Fig. 4 by means of pages S1 , S2 and S3. This does not pose any limitation to the present disclosure and an arbitrary number of pages may be provided in the security document 200. The security document further comprises a datapage 210 comprising a security inlay 100. For example, the datapage 210 may be provided as a cover page of the security document 200, e.g., a front cover page or a back cover page, separate to the pages S1 to S3. Alternatively, the datapage 210 may be provided as an additional page in addition to the cover pages and the pages S1 to S3. For example, the datapage 200 may be a sheet of polycarbonate material or a sheet of paper material as disclosed above and the disclosure of which is incorporated by reference in its entirety.

[0112] In some illustrative examples herein, the security inlay 100 of the datapage 210 may be similar to the security inlays 100 as described above with regard to the first aspect and with regard to the illustrative embodiments described above in combination with Figs. 1 , 2, and 3a to 3f.

[0113] Several attempts of forgery and / or tampering of a security document 200, as the one of Fig. 4, and of a security inlay 100, as the ones of Figs. 1 and 2, have been reported. For example, it has been reported that the chip modules 130 of the security inlays 100 have been damaged and disabled on purpose by exposing them to microwaves irradiation. For example, it has been reported that the chip modules 130 of the security inlays 100 have been damaged and disabled on purpose, in order to induce the inspectors of the security documents 200 to only rely on the graphic security features of the security documents 200, which are easier to counterfeit. These operations of tampering of the security documents 200 generally comprise placing the security documents 200 in a microwave oven and irradiating the security inlays 100 with microwaves for a short period, for example 2 seconds, to disable the chip modules 130 (which are the primary security features).

[0114] The inventors accordingly came up with the idea of providing an additional security feature in the security inlays 100 which can provide a permanent mark of a tampering attempt of the chip module 130. In fact, if a security document 200 with a security feature, such as a resonator wire 140 as the ones disclosed above, is put in a standard microwave, for example having a resonant frequency of 2.45 GHz, and irradiated with microwave radiations, not only the chip module 130 will be disabled, but also the security feature will burn in one or more portions, as shown schematically in Figs. 5a and 5b. The resonator wire 140 of Fig. 5a, for example, comprises a burnt portion configured as a burnt spot at one end of the wire. The resonator wire 140 of Fig. 5b, for example, is entirely burnt along its length.

[0115] Even if Figs. 5a and 5b show two possible configurations of the burnt resonator wires 140, it is to be understood that the one or more burnt portions of the resonator wire may be positioned anywhere along the length of the resonator wire, for instance at two ends of the wire, at the center, at one point along the length of the resonator wire, or the like, depending on the physical parameters of the microwave radiations and the physical properties of the wire (such as length and material). Accordingly, the examples of Figs. 5a and 5b do not pose any limitation on the configurations of the burnt portions of the resonator wires.

[0116] When inspecting the security document 200 of a user, the inspector may note one or more burnt portions on the resonator wire 140 and may investigate whether the chip module 130 has been disabled for criminal or tampering purposes.

[0117] References herein to terms modified by language of approximation, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. The language of approximation may correspond to the precision of an instrument used to measure the value and, unless otherwise dependent on the precision of the instrument, may indicate + / - 10% of the stated value(s).

[0118] References herein to terms such as "vertical", "horizontal", etc. are made by way of example, and not by way of limitation, to establish a frame of reference. The term “horizontal” as used herein is defined as a plane parallel to a conventional plane of a semiconductor substrate, regardless of its actual three-dimensional spatial orientation. The terms “vertical” and “normal” refer to a direction perpendicular to the horizontal, as just defined. The term “lateral” refers to a direction within the horizontal plane.

[0119] A feature "connected" or "coupled" to or with another feature may be directly connected or coupled to or with the other feature or, instead, one or more intervening features may be present. Afeature may be "directly connected" or "directly coupled" to or with another feature if intervening features are absent. A feature may be "indirectly connected" or "indirectly coupled" to or with another feature if at least one intervening feature is present. A feature "on" or "contacting" another feature may be directly on or in direct contact with the other feature or, instead, one or more intervening features may be present. A feature may be "directly on" or in "direct contact" with another feature if intervening features are absent. A feature may be "indirectly on" or in "indirect contact" with another feature if at least one intervening feature is present.

[0120] The descriptions of the various embodiments of the present invention have been presented for purposes of illustration but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

[0121] REFERENCES

[0122] 100: security inlay

[0123] 110: inlay substrate

[0124] 120: RFID antenna

[0125] 130: chip module

[0126] 140, 141 , 142, 143, 144, 145, 145’, 146, 146’: resonator wires

[0127] 150, 152: burnt portions

[0128] 200: security document

[0129] 210: datapage of a security document

[0130] S1 , S2, S3: pages of a security document

Claims

Claims1 . A security inlay (100) for a security document (200), the security inlay (100) comprising: an inlay substrate (110); an antenna (120) provided in or on the inlay substrate (110) and configured to communicate with a reader; a chip module (130) integrated into the inlay substrate (110) and coupled to the antenna (120); and at least one security feature (140) configured to burn in one or more portions (150, 152), when exposed to microwave radiations, so as to identify a security status of the security inlay (100), for example a disabled status.

2. The security inlay (100) of claim 1 , wherein the security feature (140) comprises an electromagnetic resonator wire made of conductive material.

3. The security inlay (100) of claim 2, wherein the resonator wire has a length and / or is positioned in an area having a dimension comprised between 25 mm and 70 mm, more preferably between 35 and 50 mm, even more preferably equal to 48 mm.

4. The security inlay (100) of claim 2 or 3, wherein the resonator wire (141 ) is a straight wire.

5. The security inlay (100) of any of claims 2 to 4, wherein the resonator wire (145, 145’) comprises one or more wire segments connected to each other and defining an angle equal to or larger than 90°, for example, one or more wire segments having an L-shape.

6. The security inlay (100) of any of claims 2 to 5, wherein the resonator wire (143) comprises one or more wires intersecting each other to define a cross-shape.

7. The security inlay (100) of any of claims 2 to 6, wherein the resonator wire (142) has a loopshape.

8. The security inlay (100) of any of claims 2 to 7, wherein the resonator wire (144) has the shape of an open polygon, for example an open square.

9. The security inlay (100) of any of claims 2 to 8, wherein the resonator wire (146, 146’) has the shape of a meander structure, preferably a meander structure with overlapping segments.

10. The security inlay (100) of any of claims 1 to 9, wherein the material of the antenna (120) has a first conductivity and the material of the security feature (140) has a second conductivity, and the second conductivity is lower than the first conductivity.11 . The security inlay (100) of any of claims 1 to 10, wherein the security feature is embedded in a dielectric material having a relative permittivity equal to or larger than 2.

12. The security inlay (100) of any of claims 1 to 11 , wherein the security feature (140) is electrically coupled to the antenna (120).

13. The security inlay (100) of any of claims 1 to 12, wherein the security feature (140) is electrically connected to the antenna (120).

14. The security inlay (100) of any of claims 1 to 13, wherein the security feature (140) is physically separated from the antenna (120).

15. The security inlay (100) of any of claims 1 to 14, wherein the security feature (140) is positioned within a perimeter defined by the antenna (120).

16. The security inlay (100) of any of claims 1 to 15, wherein the security feature (140) is positioned outside a perimeter defined by the antenna (120).

17. A security document (200) comprising the security inlay of one of claims 1 to 16 and one or more overlays formed on at least one exposed surface of the security inlay.

18. The security document (200) of claim 17, wherein the security document is one of a smart card, an electronic identity booklet and a datapage of an electronic booklet.

19. The security document (200) of claim 17 or 18, wherein the antenna (120) is an RFID antenna and the security document (200) is an RFID-enabled security document.

20. Method for authenticating the security document (200) of any of claims 17 to 19, the method comprising:(a) subjecting the security document to a visual inspection procedure to determine a burning status of the security feature (140); and(b) determining an authentication status of the security document on the basis of the burning status of the security feature (140).

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