CH713299A2 - Portable object having a near-field connection device. - Google Patents

Abstract

The present invention provides a portable object having a near field communication device. The communication device comprises an electronic chip (1) provided with two terminals (2, 3) connected to an electrical circuit comprising an antenna (4) and a filter (5). The communication device is arranged to receive and transmit at a defined frequency corresponding to the resonant frequency of the electrical circuit. In an original way, the portable object comprises a control member able to be moved between two predefined positions, namely an active position in which the communication device is activated and a passive position in which the communication device is deactivated. The electrical circuit further comprises a bypass branch (6) provided with a mechanical switch (7) able to switch between an open state and a closed state in response to a displacement of the control member from one to the other. other of its predefined positions by causing a change in the resonant frequency of the electric circuit.

Description

Description

TECHNICAL AREA

The present invention relates to the field of microtechnology. It relates more particularly to a portable object comprising a connection device in the near field.

PRIOR ART

It is known to make portable objects incorporating communication means in the near field for example using a radiofrequency tag. These connection means are composed of an electronic chip, or integrated circuit, electrically connected to an antenna. Most of the time, these devices do not need a standalone power supply and are intended to automatically communicate with a reader as soon as they approach it. The electromagnetic field of the reader generates a current induced in the antenna which feeds the chip and allows it to transmit in turn a signal via the antenna.

[0003] Such devices are commonly found in smart cards which make it possible to make contactless payments at the terminals provided for this purpose. Applications EP 603 721, EP 974 878, CH 690 525 or CH 704 583 are also known which describe watches comprising means of communication in the near field in which the antennas are concealed at different points of the watch such as the dial, the middle part , the telescope, the ice seal or the ice. Other configurations provide for housing the antenna in the bottom, the movement or the bracelet. The integration of these contactless communication devices in a watch allows many applications such as performing information operations, identification, locking, access control or payment.

[0004] However, these automatic communication devices have a high vulnerability vis-à-vis malicious third parties who could, by approaching a transceiver, recover without the knowledge of their owners, confidential information or execute bank transfers to their profit. Various parries have been developed to secure near-field communication devices. Payment cards can thus be placed in armored cases that act like a Faraday cage and prevent the communication from becoming established. The application US 2016/0 188 925 describes a method for activating or deactivating a radiofrequency tag having an electronic switch using an appropriate auxiliary reader. The electronic unlocking operation can be tedious and impractical since it requires manipulating another object than the one by which the communication is established. In addition, it presents a security vulnerability because the near-field communication device remains vulnerable between the moment it is activated and the time when communication is established. The various security methods known are unsuitable for some portable objects such as a wristwatch, are impractical and do not completely eliminate the risk of piracy.

SUMMARY OF THE INVENTION

The present invention aims to provide a means for securing a near-field communication device integrated with a portable object that is easy to use and safer than the solutions of the prior art.

More specifically, the invention relates to a portable object comprising a near field communication device. The communication device comprises an electronic chip provided with two terminals connected to an electrical circuit comprising an antenna and a filter. The communication device is arranged to receive and transmit at a defined frequency corresponding to the resonant frequency of the electrical circuit. In an original way, the portable object comprises a control member able to be moved between two predefined positions, namely an active position in which the communication device is activated and a passive position in which the communication device is deactivated. The electrical circuit further comprises a bypass branch provided with a mechanical switch able to switch between an open state and a closed state in response to a displacement of the control member from one to the other of its predefined positions. causing a change in the resonant frequency of the electrical circuit.

This arrangement makes it possible to secure a near-field communication device integrated in a portable object while simplifying the operations necessary for this securing.

According to an advantageous variant of the invention, the electrical circuit comprises a bridge carrying a capacitor parallel to the antenna.

According to another advantageous variant of the invention, the antenna and the bridge are connected to the terminals of the electronic chip.

According to another advantageous variant of the invention, the branch branch is connected to the terminals of the electronic chip.

According to another advantageous variant of the invention, the bridge comprises a second component connected in series with the capacitor and the branch branch is connected between the two components of the bridge and on a terminal of the electronic chip.

According to another advantageous variant of the invention, the second component is a capacitor or an inductor.

According to another advantageous variant of the invention, the branch branch comprises a component connected in series with the switch, the component being a capacitor, an inductor or a resistor.

According to another advantageous variant of the invention, an inductor is mounted between a terminal of the electronic chip and the capacitor and the branch branch is mounted parallel to the inductor.

According to another advantageous variant of the invention, the mechanical switch is a Reed switch and the portable object comprises a movable permanent magnet with reference to the Reed switch and able to change the state of the Reed switch. in response to a displacement of the control member.

According to another advantageous variant of the invention, the portable object comprises a safety switch arranged to change state simultaneously with the Reed switch in the presence of an external magnetic field.

According to an advantageous variant of the invention, the portable object comprises an elastic return means arranged to automatically return the control member from the active position to the passive position.

According to another advantageous variant of the invention, the portable object is a watch.

According to another advantageous variant of the invention, the watch comprises a pivoting bezel which is the control member.

According to another advantageous variant of the invention, the watch comprises a ring or a pusher which is the control member.

According to another advantageous variant of the invention, the portable object is a smart card.

BRIEF DESCRIPTION OF THE FIGURES

Other details of the invention will appear more clearly on reading the description which follows, made with reference to the accompanying drawings in which: FIGS. 1 to 7 represent different schematic diagrams of a device for communicating a portable object according to the invention, FIG. 8 represents a diagram of the gain of the antenna, and therefore of its performance, as a function of the frequency of a communication device according to the invention, FIGS. 9 and 10 show a sectional view of the branch branch and a switch respectively in the open and closed positions.

DETAILED DESCRIPTION

Figs. 1 to 7 represent block diagrams of the secure near-field communication device that the invention proposes to integrate into portable objects. The communication device comprises an electronic chip 1 provided with two terminals 2, 3 connected to an electrical circuit comprising an antenna 4 and a filter 5, typically a pass-band filter. The near-field communication device is arranged to receive and transmit at a defined frequency corresponding to the resonant frequency of the electrical circuit which is also the operating frequency of the reader with which the portable object is intended to communicate. The resonant frequency of the antenna is adapted to have the best performance (gain) in the useful frequency band, and thus to allow to receive and transmit in a controlled manner and according to the RFID standards in force. The electrical circuit comprises a bypass branch 6 provided with a switch 7 able to switch between an open state and a closed state. The switch 7 is controlled by the movement of a control member that includes the portable object. The control member is adapted to be moved between two predefined positions, namely an active position in which the communication device is activated and a passive position in which the communication device is deactivated. The displacement of the control member from one to the other of its predefined positions causes switching of the switch 7 and changes the resonance frequency of the electrical circuit and therefore its ability to communicate with a target reader.

In all the examples presented, the filter comprises a bridge 8 connected in parallel with the antenna 4. It is also possible that this bridge is mounted in series, and that the other components are also placed in a dual manner for obtain similar effects, without departing from the scope of the invention. Only the cases with a parallel bridge will be treated as an example in the following description.

In the examples of FIGS. 1 and 2, the bridge comprises only a capacitor 9, the antenna 4 and the capacitor 9 being connected to the terminals of the electronic chip 1. The branch branch 6 is also connected to the terminals 2, 3 of the electronic chip 1, if the switch 7 is in the closed position.

In the examples of FIGS. 3 to 6 the bridge comprises a second component 10 in addition to the capacitor 9 which may in particular be an inductor or a second capacitor. In this case the branch branch 6 is connected in parallel with the second component 10, on one side to a terminal 2 of the electronic chip 1 and on the other between the two components of the bridge 8.

The branch branch 6 may also include a component 11 connected in series with the switch 7, this component 11 may be a capacitor, an inductor or a resistor.

In the example shown in FIG. 7, an inductor 12 is connected between a terminal 3 of the electronic chip 1 and the capacitor 9 and the branch branch 6 is mounted parallel to the inductor 12.

The skilled person will create a large number of variants from the proposed examples by combining the different alternatives proposed between them.

The diagram of FIG. 8 represents the gain of the antenna of the communication device as a function of the frequency in the case of a circuit with a band-pass filter. The central reception frequency of the bandwidth is the resonance frequency f 0 of the electric circuit. The transmission frequency of the reader is in the bandwidth of the circuit. Outside this reception range, the signal is too attenuated and the communication device can no longer function. In the case of an LC circuit comprising a capacitor and a coil, the resonance frequency is given by the formula:

fo = 1/2 π VLC

The modified circuit has a new resonant frequency f sufficiently far from f0 for a signal transmitted in the frequency range of the RFID device to be no longer detected, thus deactivating the communication device.

Figs. 9 and 10 show a section of a detail of a portable object according to the invention, in this case a watch which distinguishes the housing 20. A bezel 21, pivotally mounted with reference to the housing 20, comprises a communication device in the near field such as those shown schematically in FIGS. 1 to 7 and comprising an antenna 4, an electrical circuit and an electronic chip. Conductive flexible blades 22, 23 housed in the housing 20 are arranged to come into contact with tabs 24, 25 of the electrical circuit when the window 21, which is here the control member, is in the active position shown in FIG. 10. The flexible blades 22, 23 form a branch branch 6 which may optionally comprise an additional component 11, in particular a capacitor, an inductor or a resistor. When the control member is in the passive position shown in FIG. 9, the branch branch 6 is connected to the electrical circuit via the tabs 23, 24 which has the effect of changing the resonant frequency and make the device inactive. The portable object also comprises an elastic return means 26 arranged to automatically return the control member to its passive position and thus secure the device.

The embodiment of a switch of Figs. 9 and 10 is only a non-limiting example. The skilled person will adapt other devices to achieve this function. In particular, the control member may be a push button or the control ring. In an interesting configuration, the galvanic switch described above can be replaced by a magnetic switch with a reed switch type flexible blade. In this case, the portable object also comprises a movable permanent magnet with reference to the Reed switch 26, the relative displacement of the Reed switch and the magnet being caused by the displacement of the control member. As before, the assembly is arranged so that the displacement of the control member, between its predefined positions, modifies the state of the Reed switch.

In an alternative embodiment not shown, the portable object comprises a main reed switch and an additional safety switch to guard against the risk of a fraudulent connection with a reader and d a magnet placed by a malicious third party near the portable object. This safety magnet is also a Reed switch. Unlike the main Reed switch, the safety switch is not associated with a permanent magnet because it is not intended to change state during normal operation but only in case of attack.

The safety switch can, for example, be connected in series with the main reed switch. In this case, the safety switch is a normally closed NC type switch, that is to say that it is closed in the absence of a magnetic field and that it switches to the open position under the effect of a magnetic field. The main reed switch is of the NO type, normally open, and works the opposite of the previous one. In case of attack with a magnet, the safety switch and the main switch switch simultaneously under the effect of the external magnetic field, so that the communication device remains inactive. Preferably the main reed switch and the safety switch are arranged as close as possible, ensuring that the movement of the permanent magnet controlling the main switch has no effect on the safety switch.

The skilled person will achieve multiple variations from the embodiments presented without departing from the scope of the claims. The passive position of the control member may for example correspond to an open state of the switch as well as to a closed state.

The portable objects according to the invention, offer a great ease of use and better security than those provided with electronic switches of the prior art whose change of state must be ordered in advance since

Claims (15)

an external electronic device, for example from a smartphone. It is possible to easily adapt this secure communication device in the near field on any type of portable object such as a smart card. Advantageously, the security device proposed by the invention reduces the risk of fraudulent communication because the device can be activated while the portable object is already in proximity and under the magnetic influence of the reader with which it is intended to communicate, so that the communication is established instantly with the target reader as soon as the control member is moved into the active position. In addition, the automatic return of the control member in its passive position immediately secures the device as soon as the desired operation has been performed and even when the portable object is still within the scope of the magnetic field of the target reader. Furthermore, the mechanical locking means provided by the invention gives the user control of the security of the near-field communication device and gives him the confidence that was hitherto lacking in the use of this technology. claims 1. Portable object comprising a near-field communication device, the communication device comprising an electronic chip (1) provided with two terminals (2, 3) connected to an electrical circuit comprising an antenna (4) and a filter (5) , the communication device being arranged to receive and transmit at a defined frequency corresponding to the resonant frequency of the electric circuit, characterized in that the portable object comprises a control member able to be moved between two predefined positions, namely a position active in which the communication device is activated and a passive position in which the communication device is deactivated and in that the electric circuit comprises a branch branch (6) provided with a switch (7) able to switch between a state open and a closed state in response to a displacement of the control member from one to the other of its predefined positions. by causing a change in the resonant frequency of the circuit. 2. Portable object according to claim 1, characterized in that the electrical circuit comprises a bridge (8) parallel to the antenna (4), carrying a capacitor (9). 3. Portable object according to the preceding claim, characterized in that the antenna (4) and the bridge (8) are connected to the terminals (2, 3) of the electronic chip (1). 4. Portable object according to one of the preceding claims characterized in that the branch branch (8) is connected to the terminals (2, 3) of the electronic chip (1). 5. Portable object according to one of claims 1 to 4 characterized in that the bridge (8) comprises a second component (10) connected in series with the capacitor (9) and in that the branch branch (6) is parallel connection of the second component (10) being connected on one side to a terminal (2) of the electronic chip (1) and the other between the two components of the bridge (8). 6. Portable object according to the preceding claim characterized in that the second component (10) is a capacitor or an inductor. 7. Portable object according to one of the preceding claims characterized in that the branch branch (6) further comprises a component (11) connected in series with the switch (7), the component (11) being a capacitor, inductance or resistance. 8. Portable object according to claim 2 characterized in that an inductor (12) is mounted between a terminal (3) of the electronic chip () and the capacitor (9) and in that the branch branch (6) is mounted parallel to the inductor (12). 9. Portable object according to one of the preceding claims characterized in that the switch (7) is a Reed switch and in that the portable object comprises a movable permanent magnet with reference to the Reed switch and adapted to change the state of the Reed switch in response to a displacement of the control member. 10. Portable object according to claim 9 characterized in that it comprises a safety switch arranged to change state simultaneously with the Reed switch in the presence of an external magnetic field. 11. Portable object according to one of the preceding claims, characterized in that it comprises an elastic return means (26) arranged to automatically return the control member from the active position to the passive position. 12. Portable object according to one of the preceding claims, characterized in that the portable object is a watch. 13. Portable object according to the preceding claim characterized in that it comprises a pivoting bezel (21) and in that the control member is the bezel (21). 14. Portable object according to the preceding claim characterized in that it comprises a ring or a pusher and in that the control member is the crown or the pusher. 15. Portable object according to one of claims 1 to 11 characterized in that the portable object is a smart card.