WO2018161102A1

WO2018161102A1 - Deactivatable shielding element

Info

Publication number: WO2018161102A1
Application number: PCT/AT2018/060059
Authority: WO
Inventors: Gernot Schmid
Original assignee: Seibersdorf Labor Gmbh
Priority date: 2017-03-09
Filing date: 2018-03-07
Publication date: 2018-09-13

Abstract

The invention relates to a shielding element (2) for attaching to an object (1), comprising an RFID or NFC transponder. The shielding element (2) has a pushbutton switch (24) and a flat metal layer (21) that shields electromagnetic fields, which are generated by an external reading device and are directed towards the transmission antenna (12) of the RFID or NFC transponder chip (11), when the shielding element (2) contacts the object (1) as long as the pushbutton switch (24) is not actuated. According to the invention, the metal layer (21) is provided with a slot (22) which partly interrupts the flat electrically conductive structure of the metal layer (21). In the starting state, the slot (22) is electrically bridged by the pushbutton switch (24) at one position. When the pushbutton switch (24) is actuated, the electric bridge of the slot (22) is interrupted, whereby the shielding element (2) is converted from the starting state into another state in which the electromagnetic fields that are generated by an external reading device and are directed towards the transmission antenna (12) of the RFID or NFC transponder chip (11) are no longer shielded to a sufficient degree so that a data communication between the external reading device and the RFID or NFC transponder chip (11) is possible.

Description

Deactivatable shielding element

The invention relates to a shielding element for attachment to a, in particular for NFC or RFID communication provided subject to prevent wireless data transmission. As an object in this context, any object can be viewed in the theoretically an RFID / NFC transponder can be installed, such as in particular smart cards and passports. However, the invention is by no means limited to this type of article, but works with all different types of articles with RFID / NFC functionality, such as RFID / NFC readers, in particular NFC-equipped mobile phones.

In the course of the diffusion of RFID or NFC technology and their applications in the mass market, more and more contactless smart cards, such as check credit and access cards, are stored on which sensitive and / or personal data are stored, such as health card, passport , Driving licenses, key cards for buildings or rooms, etc., or that allow cashless payment at corresponding NFC terminals in the retail sector, such as "Paypass" in Austria, the cards do not contain a battery and contain an NFC or RFID Transponder, which is supplied with energy by the magnetic field directed to the card by an external reader and also uses this magnetic field for wireless data communication Access over ranges of typically up to 10 cm. Such map n are used wherever the card must be brought by the user to the reader, in which case the reader antennas are relatively small, typically less than 100 cm ² . Examples of this are point-of-sale terminals with NFC payment options, readers in connection with door openers (eg for hotel room key cards, access cards to sensitive areas) and NFC-compatible mobile phones. With so-called "Vicinity" cards, much larger reading ranges of up to about 1 m are possible, which makes these cards suitable for access control to event and sports grounds (eg ski areas) The user no longer has to bring the card closer to the reader antenna Instead, it simply has to carry the card with it and approach the reader antenna to gain access, typically controlled by a turnstile system, to realize the larger ranges of Vicinity systems, correspondingly larger reader antennas, with antenna areas typically> 1000 cm ² , Basically, the achievable reading range depends on the antenna size, as well as on the transmission strength and the receiving sensitivity of the readers, so that it is basically possible with appropriately designed readers, which may not be standard compliant but quite easily feasible, much larger read ranges, even for proximity To achieve cards.

For this reason, data protection organizations increasingly express more concerns about the threat to data protection and possible financial damage due to unauthorized or unintentional read-out of such cards.

A protection concept against unauthorized access to the data of contactless chip cards is described, for example, in DE 10 2005 047 048 A1, in which the antenna circuit of the card can be interrupted or closed by a switch to be actuated by the user and thus the RFID / NFC functionality the card can be deactivated or activated by the user. The disadvantage of this concept lies in the costly modification of the cards themselves, so this concept has not prevailed until today.

Another protective concept is described in US 2006/02930327 A1, in which a protective device to be placed in the vicinity of the card to be protected, an electronic detection circuit is provided, which can detect magnetic fields originating from RFID / NFC readers. If the protective device detects such a magnetic field, the protective device responds faster to the reader with dummy data than the card to be protected, thereby preventing data access to the card to be protected. The disadvantage of this method is also the relatively large technical complexity of the realization of such a protective device.

In order to prevent unauthorized or unintentional data access to such Kontaktlos- chip cards in a simple manner without having to intervene in the currently widely used card technology, different shields, in particular in the form of protective covers known from the prior art.

Such protective covers typically include at least one full-surface metal layer which, when the card is inserted in the envelope, is located in the immediate vicinity of the card and covers the projection surface of the antenna in the card. As a result, the magnetic fields generated by external readers and directed to the card for power and data communication, which typically have a frequency of 13.56 MHz induces eddy currents in the metal layer, which weaken the reader field according to the law of induction so far that a data access to the card is suppressed. DE 4401089 A1 describes such a principle. A modified form of this protection concept is RFID protection cards available on the market, which must be kept in the card case or in the wallet in close proximity to the card to be protected in order to prevent data access. These protection cards include, like the protective sheaths described above, at least one full-surface metal layer covering the projection surface of the antenna in the card.

All such products have in common that the RFID / N FC card must be placed in a sheath or kept in the immediate vicinity of the protection card in order to achieve the desired shielding effect, which is disadvantageous for some applications in practice.

In fact, if the smart card's wireless functionality is to be provided, some shields known in the art may require removal and removal of the contactless transaction card from the shield. Also, other non-wireless transactions with the smart card, such as using the magnetic stripe or merely displaying the card, require, for example, removal of the card from the shield.

In addition, the total size or overall thickness of the chip card is considerably increased by the sheath in some known from the prior art shields. It is no longer possible to match the smart card according to its actual function, e.g. to use as ATM card, since the chip card with the shield does not fit in the feeder of the reader and also the contact points or the magnetic stripe for the reader are not accessible. In addition, smart cards are thickened by the cover by a factor of 3-10 and find in many common purses no more space.

An advance in simplicity while providing easy handling of RFID / NFC shielding products is provided by arrangements in which the shielding effect can be selectively and temporarily disabled by the user. WO 2015/1 13087 A1 describes an arrangement in which a conductor path running around the edge of the shielding element in the form of a coil is provided in a shielding element abutting the card to be protected, the terminals of which are in an initial state via a tactile switch with normally closed contact. Function are shorted. In this state, the shielding leads to a weakening of any acting Magnetic fields of readers, as propagate in the shorted coil induction currents that weaken the magnetic field of the reader according to the law of induction and thus significantly reduce the antenna coil of the card to be protected passing magnetic flux, thus preventing wireless data access to the card or the transmission range is reduced to a safe level. Upon actuation of the intended push-button switch with normally-closed function, the short circuit existing in the initial state between the terminals of the coil is interrupted, as a result of which no field-weakening induction currents can form in the coil, and the RFID / NFC functionality of the card to be protected is utilized can be without having to remove the card from the shielding.

In an embodiment variant also described in WO 2015/1 13087 A1, the shielding element comprises a resonant circuit consisting of coil and capacitor, which in an initial state is tuned to the resonant frequency of the card to be protected. The immediate application of such a shielding element to the card to be protected results in a close inductive coupling between the resonant circuit in the shielding element and the antenna circuit of the card to be protected, which shifts the resulting resonant frequency of the lower frequencies below the RFID / NFC transmission frequency , which suppresses RFID / NFC communication with the card. By means of an intended tactile switch in the resonant circuit of the shielding element, the resonant frequency of the shielding element can be increased to the extent that a resulting resonant frequency of the coupled system consisting of shielding element and card adjusts only insignificantly from the RFID / NFC transmission frequency and thus RFID / NFC access to the card is possible, which again the desired effect of a selective and temporary deactivation of the screening effect by the user is achieved and the card must not be removed from the shielding element when using the RFID NFC functionality.

The disadvantage of the last-mentioned shielding elements with selectively and temporarily deactivatable by the user shielding is that the geometry of the shielding element provided in the coil arrangement must be adapted to the geometry of the antenna in the card to be protected in the initial state (with active shielding) sufficient To achieve shielding effect, and the variety of existing in practice antenna geometries in RFID / NFC transponders is very large. If, for example, a coil circulating along the outer peripheral edge is provided in the shielding element, but in the adjacent card to be protected, one is provided If the size of the antenna is considerably smaller, it is possible, especially with small reader antennas, to read data from the card to be protected. If, instead of a coil concentrated on the outer edge of the shielding element, a coil distributed over the entire area of the shielding element is used, there is the problem that the ohmic resistance of the coil becomes too large and as a result induction currents which are sufficiently large can no longer be formed, which leads to a degradation of the coil Shielding effect leads. Coils with more than one turn and connectable terminals also have the problem that they can be realized only in a two-layer structure of printed circuits and thus relatively expensive to produce. Conversely, using coil geometries in the shield, consisting of only a very wide turn, so that the coil covers almost the entire area of the shield, there is the problem that for cards with very small antennas, the entire antenna may be completely behind the coil surface forming metal surface comes to rest, whereby the selective deactivability of the shielding effect is lost, even if the terminals of the coil are separated by the contact switch with opener function.

The object of the invention is therefore to provide a simple to produce, screening element for objects with RFID NFC transponder available whose shielding is given for all relevant transponder antenna geometries and selectively and temporarily deactivated by the user.

Preferred embodiments of the invention, which solve some of the above individual problems, are set forth in the dependent claims.

The invention solves this problem with a shielding element of the type mentioned above with the features of patent claim 1 or 3.

According to the invention, a shielding element is further provided for attachment to an article comprising a base body, an RFID or NFC transponder comprising a transponder chip, and a coil-shaped transmission antenna connected to the RFID or NFC transponder chip. In this case, it is provided that the shielding element has a pushbutton switch and a flat metal layer, and wherein a slot is provided in the metal layer, which partially breaks through the areally electrically conductive structure of the metal layer, and - Wherein the key switch in its initial state, the two mutually electrically separated by the slot and separated from each other at the slot parts of the metal layer electrically conductively connects, and wherein the key switch interrupts this connection when actuated.

The concrete switchable shielding effect by the shielding element can advantageously provide that the metal layer, the slot and the tactile switch are arranged such that

- The shielding in the event that the push-button switch is in the initial state, generated by an external reader and shielding the transmission antenna of the RFID or NFC transponder chip directed electromagnetic fields, and

- The shielding in the event that the key switch is actuated, is generated by an external reader and transmits to the transmitting antenna of the RFID or NFC transponder chip, in particular so permeable that a data communication between an external reader and an RFID or NFC - Transponder chip through the shielding is possible therethrough.

According to the invention, a shielding element is further provided for attachment to an article comprising a base body, an RFID or NFC transponder comprising a transponder chip, and a coil-shaped transmission antenna connected to the RFID or NFC transponder chip. In this case, it is provided that the shielding element has a push-button switch and a flat metal layer which, when the shielding element is in contact with the object, as long as the push-button switch is not actuated, the electromagnetic fields generated by an external reading device and directed onto the transmitting antenna of the RFID or NFC transponder chip shields, so that no data communication between the external reader and the RFID or NFC transponder chip is possible, wherein in the metal layer, a slot is provided which partially breaks the planar electrically conductive structure of the metal layer, that in the initial state of the slot at a position through the Tastschalter is electrically bridged, and that the operation of the key switch, the electrical bridging of the slot is interrupted, whereby the shielding element is converted from the initial state in another state in which generated by an external reader and directed to the transmission antenna of the RFID or NFC transponder chip electromagnetic fields are no longer sufficiently shielded, so that data communication between the external reader and the RFID or NFC transponder chip is possible. An advantageous embodiment, which sufficiently reduces the shielding effect of the shielding element for most contactless card types when the switch is actuated, provides that the slot does not extend entirely within the metal layer.

For the same purpose it can be provided that the slot breaks through the outer contour of the metal layer at at least one point outer contour and / or opens out of the metal layer.

An advantageous for the shielding positioning of the key switch provides that the key switch is located in the vicinity of the mouth of the slot of the metal layer and / or in the vicinity of that point at which the slot breaks through the outer contour.

In this case, to further improve the shielding effect, it can be advantageously provided that the position of the areas of the metal layer contacted by the terminals of the pushbutton switch is less than 4 cm, in particular less than 2 cm, from the region of the opening of the slot from the metal layer or from the area at which the slot breaks through the outer contour of the metal layer, are removed.

An advantageous embodiment, which sufficiently reduces the shielding effect of the shielding element for most contactless card types when the switch is actuated, provides that the slot has one or more branches.

In order to sufficiently reliably reduce the shielding effect of the shielding element for special contactless cards with very small antennas when the switch is actuated, it may be provided that the slot or its branches have the shape of self-contained or open polygon lines, or self-contained or open ones Have arc segments.

A preferred adaptation to the object to be shielded provides that the total length of the electrically bridgeable by the push button slot including its branches is not greater than the length of the outer circumference of the largest projection surface of the metal layer.

The shielding effect can be improved if the position of those portions contacted by the terminals of the key switch is at a position of that branchless portion of the slot, which adjoins the mouth of the metal layer are located. In particular, these positions are not more than 4 cm, preferably not more than 2 cm away from the mouth.

The shielding effect of the shielding element is improved if the width of the slot which can be electrically bridged by the push-button switch and its branches is no greater than 10 mm at any point, in particular no greater than 0.5 mm at any point.

An embodiment which ensures reliable shielding of different types of contactless cards, provides that the largest projection surface of the metal layer is at least the largest projection surface of the transmission antenna.

In order to adapt the shielding effect to special types of contactless card types, provision can be made for further slots to be provided in the metal layer for controlling eddy current formation in the metal layer, which do not open into the slot which can be electrically bridged by the switch or its branches.

To improve the shielding effect for contactless cards with very small antennas, it can be provided that the surface area of the metal layer minus the sum of the area contents of all slots is greater than 80% of the area enclosed by the outer contour of the metal layer.

In order to achieve an improved shielding effect also in transmission frequency ranges of older RFID transponder technologies, it can be provided that, in addition to the metal layer, a resonant circuit is provided whose resonant frequency, as long as the pushbutton is not actuated, is in the frequency range between 80 kHz and 200 kHz.

For deactivating the shielding effect for these older RFID transponder technologies, it can be provided that the resonance circuit is electrically interrupted when the pushbutton is actuated.

Alternatively, it can also be provided that the resonant frequency of the resonant circuit is less than 80 kHz or more than 200 kHz when the pushbutton is actuated. An embodiment of the shielding element, which is particularly easy to produce, provides that the metal layer is applied to a support of electrically non-conductive material.

For this purpose it can be advantageously provided that the carrier is formed as a film, wherein the metal layer is applied, printed or vapor-deposited in particular on the film or is integrated in the film, wherein the film is preferably formed as an adhesive film, which on the body of the The article is glued, and / or the total thickness of the film is preferably less than 0.5 mm.

A particularly effective shielding can be achieved if the metal layer has the shape of the article.

A simple deactivation of the shielding effect by means of electronic control can be achieved by the push-button switch is formed by an electronic switch, in particular a field effect transistor.

A simple deactivation of the shielding effect by contact can be achieved if a, in particular capacitive, touch sensor is provided, which opens the electronic switch upon detection of a touch.

An advantageous development of the shielding element, which allows easy handling and mechanical protection of the object, provides that the base body has a container for the article or that the shielding element is connected to a container for the article, in particular adhesively bonded thereto or in the Container is integrated.

Additionally, to achieve improved shielding, in the event the article is in the container, wireless communication between the RFID or NFC transponder of the article may be effectively suppressed by the metal layer of the shielding element as long as the switch is not actuated becomes.

It is preferably provided that the container is designed in the form of a shell or a case. Particularly advantageous is a combination of a shielding element according to the invention with an object having a base body, an RFID or NFC transponder and a transmission antenna, wherein the shielding element abuts the object and in particular glued to this or integrated into the object.

An extension of the scope of the present invention is a combination of a shielding element according to the invention with an article comprising a base body, an RFID or NFC transponder and a transmission antenna, the object being a contactless smart card or a mobile phone equipped with an NFC interface.

Several embodiments of the invention will be described in more detail with reference to the following drawing figures.

Fig. 1 shows a first object to be shielded. Fig. 2 shows a first embodiment of a shielding element. Fig. 3 shows a further embodiment of the shielding. 4 shows an inventive shielding element in the initial state with active shielding effect. 5 shows the shielding element in the state with a temporarily deactivated shielding effect. 6a to 6c show different embodiments according to the invention of a metal layer contained in the shielding element and determining the shielding effect. FIG. 7 shows a shielding element according to the invention, which has a resonant circuit in addition to the metal layer. 8 shows an arrangement according to the invention of the shielding element on a subject to be shielded. 9 shows an oblique view of an arrangement according to the invention of the shielding element on a container for receiving an object to be shielded. Fig. 10 shows an oblique view of how the object to be shielded, such as a contactless chip card, is to be inserted into the container in order to achieve the shielding effect. Fig. 11 shows a side view of an inventive arrangement in which the object to be shielded is completely inserted in a container on the surface of which the shielding element is arranged. Fig. 12 shows a special inventive combination of the shielding element according to the invention, in which the object to be shielded is formed by a mobile phone, on the back, in the region of the NFC antenna of the mobile phone, the shielding element according to the invention is dismantled.

In Fig. 1, a chip card 1 is shown, which has a base body 10. In the main body 10 are an RFID or NFC transponder chip 1 1 and one to this connected, coil-shaped transmission antenna 12 is arranged, which together form a transponder. In addition, the chip card 1 has additional functions and has a magnetic strip, not shown, as well as an electrical contact field for use in contact-type data transmission, such as in a ATM card. The chip card 1 has no power supply located on it and obtains the energy necessary for its operation from the electromagnetic field created by a reading device. The data transfer from the chip card 1 to the reader is preferably via load modulation, so that can be realized by the smart card 1 as a purely passive component with low buffer capacity. The embodiment of a chip card shown in FIG. 1 also applies to other contactless cards with RFID / NFC transponders, such as access cards, which do not necessarily have a magnetic strip and / or a contact field for contact-type data transmission.

2, a first exemplary embodiment of a shielding element 2 is shown, which comprises an electrically conductive metal layer 21 and a push-button switch 24 with an opener function. In the illustrated embodiment, the planar electrically conductive structure of the metal layer is interrupted by a rectilinear slot 22. In the present embodiment, the slot 22 opens out of the metal layer 21. The slot 22 breaks through the outer contour 27 of the metal layer 21 at at least one point. The slit 22 is electrically bridged at a position near the edge of the metal layer 21 by the key switch 24.

The positioning and contacting of the terminals of the key switch 24 advantageously takes place on two opposite sides of the slot 22 delimiting metal layer 21 opposite positions of the mouth of the slot of the metal layer.

The position of those portions contacted by the terminals of the key switch 24 is typically selected near the edge of the metal layer 21 in the present embodiment at locations from the region of the mouth of the slot from the metal layer or region the slot breaks the outer contour of the metal layer, less than 4 cm, in particular less than 2 cm, are removed.

If such a shielding element 2 is in an alternating magnetic field, eddy currents are induced in the metal layer 21 which, in accordance with the law of induction of their Cause are opposite and thus weaken the resulting alternating magnetic field in the shielding element 2. In the state of the shielding element shown in Fig. 2, the slot 22 is electrically bridged by the key switch 24 and the eddy currents flow through the key switch 24, whereby a strong weakening of the resulting magnetic field in the region of the shield 2 is effected, and subsequently a good Shielding effect is achieved for located in the immediate vicinity of the shielding RFID or NFC transponder. The embodiment of the shielding element shown in FIG. 2 is particularly well suited for chip cards 1 whose transmission antenna runs exclusively along or in the vicinity of the outer peripheral edge.

FIG. 3 shows a further preferred exemplary embodiment of the shielding element 2, which differs from the variant shown in FIG. 2 in that the slot 22 has a branching into two branches 22a. In principle, the distribution of the eddy current formation in the metal layer 21 can be controlled by different courses and geometries of slots in the metal layer 21, as well as by the position of the key switch 24. For the realization of a deactivatable shielding effect, both the eddy current curves are included in the closed key switch 24, as well as open push-button 24 in the considerations in the determination of the slot geometry and slot gradients, on the one hand reliable shielding when the push button 24 closed, and on the other hand reliable response of the Shielding element adjacent chip card 1 to allow for open push-button 24, whereby the concrete forms of the transmission antennas 12 of the chip card 1 play a significant role. For chip cards 1 with transponder antennas 12, which extend to a significant part in the form of a narrow rectangle only one half of the chip card 1, would be in a slot geometry as shown in Fig. 2, the transmission antenna 12 completely come to rest under a full-surface metal surface, which would lead to the shielding effect could not be canceled by pressing the push button 24. The special course of the slot 22 and its branches 22a shown in FIG. 3 avoids this problem.

The position of those portions contacted by the terminals of the key switch 24 is typically selected near the edge of the metal layer 21, in the present embodiment, at a location of the non-branched portion of the slot 22 adjacent to the mouth of FIG Metal layer 21 connects. Advantageously, the contacts of the push-button 24 are not more than 4 cm, in particular not more than 2 cm, away from the mouth.

4 shows a particularly easily produced embodiment of a shielding element 2 according to the invention, in which the metal layer 21 is applied to a carrier 26 made of electrically non-conductive material. The geometry of the slot 22 and its branches 22a corresponds to the shape shown in Fig. 3. In the state of the shielding element shown in Fig. 4 is the initial state in which the push button switch 24 is not actuated and thus causes an electrical bridging of the slot 22. If the shielding element is brought into an alternating magnetic field in this initial state, eddy currents can form along the circumference of the metal layer 21 and over the pushbutton 24, whereby the acting alternating magnetic field in the region of the shielding element 21 is weakened. A voltage applied to the shielding 2 chip card 1 (see Fig. 8) is thus protected against data access.

Fig. 5 shows the shielding element 2 shown in Fig. 4 in the state with actuated push-button 24, whereby the eddy current propagation along the peripheral edge is interrupted by the slot 22 and the field weakening effect of the eddy currents is significantly reduced. As a result, the shielding effect of the shielding element 2, as long as the push-button switch 24 is actuated, temporarily disabled. If, in this state of the shielding element 2, a chip card 1 abuts on the shielding element 2 (FIG. 8), the chip card 1 is still sufficiently filled with magnetic flux, so that data access to the chip card is possible.

6a to 6c show further embodiments of shielding elements according to the invention, which are characterized by further branches 22a of the slot 22 (FIG. 6b) and additional slots 25 separated from the slot 22. While in all the embodiments shown in FIGS. 6 a to 6 c, the slit 22 breaks through the outer peripheral edge 27 of the metal layer 21, the slits 25 lie completely within the metal layer 21 and do not break through the outer peripheral edge 27 of the metal layer 21. By the targeted arrangement of special slot shapes 22 with specially arranged branches 22a, as well as by the position of the key switch 24, and the provision of additional slots 25, the shielding effect can be tailored to different shapes you sizes of transmission antennas 12 adapted. An inventive shielding element 2 is therefore not on in the drawing figures shown arrangements, shapes and number of slots 22, 22 a and 25, as well as the positions of the switch 24 shown in the drawing figures restricted.

FIG. 7 shows a further preferred embodiment of a shielding element 2 according to the invention, in which, in addition to the metal layer 21, a resonant circuit is provided which comprises a coil 28 which wraps around the metal layer 21. The capacitances also required for the resonant circuit are not explicitly shown in FIG. In practice, the required capacities can be realized by the stray capacitances of the coil windings or stray capacitances between coil windings and the metal layer. A concrete installation of capacitors in the shielding is of course also possible. The additional resonant circuit 28 provided in the shielding element 2 also enables shielding of alternating magnetic fields at low transmission frequencies, in particular in the frequency range from 80 kHz to 200 kHz, for which a shielding effect based solely on the frequency-proportional eddy-current induction is insufficient. The resonant frequency of the resonant circuit 28 is tuned to the transmission frequency of the chip card 1 to be shielded and is preferably in the frequency range between 80 kHz and 200 kHz. As long as the key switch 24 is in its initial state, the slot 22 is electrically bridged by the key switch 24 and the resonant circuit 28 is closed by the key switch 24. If an alternating magnetic field with a frequency corresponding to the resonant frequency of the resonant circuit 28 acts on such an inventive shielding element 2, a high induction current flows in the resonant circuit, which leads to the desired field-weakening effect. For higher transmission frequencies sufficient field-weakening effect is achieved by the eddy current induction in the metal layer 21. Upon actuation of the key switch 24 on the one hand, the electrical bridging of the slot 22 is repealed and on the other hand, the resonant circuit is interrupted. As a result, the field-weakening eddy currents or induction currents in the shielding element 2 are greatly reduced or suppressed and the shielding effect is deactivated as long as the button 24 remains actuated. Alternatively to the interruption of the resonant circuit by the actuation of the key switch 24, it is of course also possible to deactivate or activate a resonant frequency-determining element of the resonant circuit 28 by the actuation of the key switch 24, so that the resonance frequency of the resonant circuit 28 deviates sufficiently from the transmission frequency, to limit the induction current in the resonant circuit so far that it no longer causes sufficient field weakening. 8 shows a side view of a combination according to the invention of a shielding element 2 according to the invention with an object 1, in particular a chip card with RFID or NFC transponder. The shielding element 2 is the chip card 1 closely and congruent. To achieve a permanent congruent concern of the shielding element 2 on the chip card 1, the shielding element 2 may be glued on the chip card 1. In particular, the embodiment of the shielding element shown in FIGS. 4 and 5, in which the metal layer 21, and optionally the resonant circuit 28, are applied to a carrier 26, is suitable for this purpose. In this case, the shielding can be made as a self-adhesive part that can be glued to the chip card.

9 shows an oblique view of an embodiment in which a shielding element 2 according to the invention is connected to a container 29. The container 29 is designed specifically for the reception of flat objects with RFID or NFC transponder.

Fig. 10 illustrates how an article 1, in particular a contactless chip card, is to be introduced into the container 29 shown in Fig. 9 in order to shield the article 1 from data access.

FIG. 11 shows a container 29 connected to a shielding element 2 according to the invention, with inserted chip card 1. In the illustrated embodiment, the metal layer 21 is disposed directly on the container 29. Of course, it is also possible that the metal layer 21 is disposed on an electrically non-conductive support, which lies between the metal layer 21 and the container. Preferably, in this case, the carrier has an adhesive layer by means of which it can be adhered to the container.

Fig. 12 shows an oblique view of an inventive combination of a shielding element 2 according to the invention with an object 1, wherein the object 1 in the illustrated embodiment is a mobile phone with NFC interface. The shielding member 2 is disposed on the back of the cellular phone 1 so as to cover the largest projection area of the NFC transmitting antenna in the cellular phone 1, thereby preventing access to the NFC interface of the cellular phone 1 as long as the tactile switch 24 is not operated. In particular, the embodiment of the shielding element shown in Fig. 4 and Fig. 5, in which the metal layer 21, and optionally the resonant circuit 28, are applied to a carrier 26 is suitable for this purpose. In this case, the shielding can be made as a self-adhesive part, which can be adhered to the back of the mobile phone 1. Alternatively, it is of course, however, also possible to integrate the shielding element 2 in a container, such as a protective cover for the mobile phone.

Claims

claims:

1 . Shielding element (2) for attachment to an object (1) comprising a base body (10), an RFID or NFC transponder comprising a transponder chip (1 1) and a coil-shaped to the RFID or NFC transponder chip (1 1) connected Transmission antenna (12),

- wherein the shielding element (2) has a push-button switch (24) and a flat metal layer (21), and wherein in the metal layer (21) has a slot (22) is provided, which partially breaks the planar electrically conductive structure of the metal layer (21) , and

- Wherein the key switch in its initial state, the two electrically separated by the slot (22) and the slot (22) opposite parts of the metal layer (21) electrically conductively connected, and wherein the momentary contact switch (24) interrupts this connection when actuated.

2. Shielding element according to claim 1, characterized in that the metal layer (21), the slot (22) and the push-button switch (24) are arranged such that

- The shielding (2) in the event that the key switch (24) is in the initial state, produced by an external reader and on the transmission antenna (12) of the RFID or NFC transponder chip (1 1) directed electromagnetic fields shields, and

- The shielding element (2) in the event that the push button switch (24) is actuated, for by an external reader generated and on the transmission antenna (12) of the RFID or NFC transponder chip (1 1) directed electromagnetic fields is permeable, in particular so permeable that a data communication between an external reader and an RFID or NFC transponder chip (1 1) through the shielding element (2) is possible therethrough.

3. shielding element (2) for attachment to an object (1) having a base body (10), an RFID or NFC transponder comprising a transponder chip (1 1) and one to the RFID or NFC transponder chip (1 1) having connected coil-shaped transmission antenna (12),

- Wherein the shielding element (2) has a pushbutton switch (24) and a flat metal layer (21) which, when the shielding element (2) on the object (1), as long as the pushbutton (24) is not actuated, by an external reader generated and on the transmission antenna (12) of the RFID or NFC transponder chip (1 1) shields directed electromagnetic fields, so no data communication between the external reader and the RFID or NFC transponder chip (1 1) is possible, characterized

a slot (22) is provided in the metal layer (21) which partially breaks through the areally electrically conductive structure of the metal layer (21).

that in the initial state, the slot (22) is electrically bridged at a position by the push-button switch (24), and

in that the electrical bridging of the slot (22) is interrupted by actuation of the push-button switch (24), whereby the shielding element is transferred from the initial state into a further state in which the data generated by an external reading device and transmitted to the transmission antenna (12) of the RFID or NFC transponder chips (1 1) directed electromagnetic fields are no longer sufficiently shielded, so that a data communication between the external reader and the RFID or NFC transponder chip (1 1) is possible.

4. shielding (2) according to one of claims 1 to 3, characterized in that the slot (22) does not extend entirely within the metal layer (21), and / or that the slot (22), the outer contour (27) of the metal layer (21) breaks through at least one point and / or out of the metal layer (21).

5. Shielding element according to claim 4, characterized in that the push-button switch (24) is arranged in the vicinity of the mouth of the slot of the metal layer and / or in the vicinity of the point at which the slot (22) breaks through the outer contour (27),

and that in particular

the position of the areas of the metal layer contacted by the terminals of the key switch (24) is less than 4 cm, in particular less than 2 cm, from the region of the opening of the slot from the metal layer or from the region where the slot breaks the outer contour of the metal layer are.

6. Shielding element (2) according to one of the preceding claims, characterized in that the terminals of the pushbutton switch (22) are arranged on two opposite sides on opposite sides of the slot-limiting metal layer.

7. Shielding element (2) according to one of the preceding claims, characterized in that the slot (22) has one or more branches (22a).

8. Shielding element (2) according to one of the preceding claims, characterized in that the slot (22) or its branches (22a) have the shape of self-contained or open polygon lines, or self-contained or open arc segments.

9. Shielding element (2) according to one of the preceding claims, characterized in that the total length of the push-button (24) electrically bridgeable slot (22) including its branches (22a) is not greater than the length of the outer circumference (27) of largest projection surface of the metal layer (21).

10. Shielding element (2) according to one of claims 7 to 9, characterized in that the position of those areas which are contacted by the terminals of the push-button (24), at a location of that branching-free portion of the slot (22), to the Outlet of the metal layer (21) connects, are located and in particular that these positions are located not more than 4 cm, preferably not more than 2 cm, away from the mouth.

1 1. Shielding element (2) according to one of the preceding claims, characterized in that the width of the push-button (24) electrically bridgeable slot (22) and its branches (22a) at any point is greater than 10 mm, in particular at any point is greater than 0.5 mm.

12. Shielding element (2) according to one of the preceding claims, characterized in that the largest projection surface of the metal layer (21) is at least 70% of the largest projection surface of the transmission antenna (12).

13. Shielding element (2) according to one of the preceding claims, characterized in that further slots (25) in the metal layer (21) for controlling the eddy current formation in the metal layer (21) are provided which are not in the electrically bridged by the switch slot (22) or its branches (22a).

14. Shielding element (2) according to one of the preceding claims, characterized in that the surface area of the metal layer (21) minus the sum of the surface areas of all slots (22, 25) is greater than 80% of the outer contour of the metal layer (21) enclosed surface content.

15. Shielding element (2) according to one of the preceding claims, characterized in that in addition to the metal layer (21) a resonant circuit (28) is provided, the resonant frequency, as long as the push-button (24) is not actuated, in the frequency range between 80 kHz and 200 kHz is.

16. shielding element (2) according to claim 15, characterized in that upon actuation of the pushbutton switch (24) of the resonant circuit (28) is electrically interrupted.

17. Shielding element (2) according to claim 15, characterized in that upon actuation of the key switch (24), the resonant frequency of the resonant circuit (28) is less than 80 kHz or more than 200 kHz.

18. Shielding element (2) according to one of the preceding claims, characterized in that the metal layer (21) on a support (26) is applied from electrically non-conductive material.

19, shielding element (2) according to claim 18, characterized in that the carrier (26) as a film (26 a) is formed, wherein the metal layer (21) in particular on the film (26 a) is applied, printed or vapor-deposited or in the film (26a) is integrated,

- wherein the film (26 a) is preferably formed as an adhesive film which is adhered to the base body (10) of the article (1), and / or

- Wherein the total thickness of the film (26a) is preferably less than 0.5 mm.

20. Shielding element (2) according to one of the preceding claims, characterized in that the metal layer (21) has the shape of the article (1).

21. Shielding element (2) according to one of the preceding claims, characterized in that the push-button switch (24) is formed by an electronic switch (24), in particular a field-effect transistor.

22. Shielding element according to claim 21, characterized in that a, in particular capacitive, touch sensor (241) is provided which opens the electronic switch (24) upon detection of a touch.

23. Shielding element (2) according to one of the preceding claims, characterized in that

- That the base body (10) has a container (29) for the object (1) or

- That the shielding element (2) with a container (29) for the object (1) is connected, in particular glued to this or integrated into the container.

24. shielding element (2) according to claim 23, characterized in that the metal layer (21) is arranged on the container (29), that in the event that the object (1) is in the container (29), a wireless communication between the RFID or NFC transponder of the article (1) is effectively suppressed by the metal layer (21) of the shielding (2), as long as the switch (24) is not actuated.

25. Shielding element according to claim 23 or 24, characterized in that the container (29) is designed in the form of a shell or a case.

26. Combination of a shielding element (2) according to one of the preceding claims with an article (1) which has a base body (10), an RFID or NFC transponder and a transmission antenna (12),

wherein the shielding element (2) rests against the object (1) and in particular glued to it or integrated into the object (1).

A combination according to claim 26, wherein the article (1) is a contactless smart card or a mobile phone equipped with NFC interface.

Combination according to claim 26 or 27, wherein the metal layer (21) has the shape of the article (1) or is adapted to the shape of the article (1).