FR2852170A1 - TRANSMISSION AND / OR RECEPTION DEVICE AND SECURITY SYSTEM INCLUDING SUCH A DEVICE - Google Patents

Abstract

The invention relates to a transmission and / or reception device for a system for securing an enclosed space which comprises fixed equipment (4, 5, 6, 7), linked to the enclosed space, as well as a device. portable identification device (3) and in which the fixed equipment (4, 5, 6, 7) and the portable identification device (3) communicate by exchanging radio frequency signals (17). According to the invention, the transmission and / or reception device (10) comprises: - an antenna element (11) formed of a single support element (12) around which are arranged a first (13) and a second (14) windings, - a first (15) and a second (16) electronic circuits connected to the antenna element (11) and respectively allowing communication between the fixed equipment (4, 5, 6, 7) and the device of portable identification (3), in a first (A) and a second (B) modes of communication of the radiofrequency signals (17). The invention also relates to a system for securing an internal confined space. granting such a transmission and / or reception device (10).

Description

TRANSMISSION AND / OR RECEPTION DEVICE AND SECURITY SYSTEM

INTEGRATING SUCH A DEVICE

  The present invention relates to a device for transmitting and / or receiving radio frequency signals for a system for securing an enclosed space, in particular a motor vehicle.

  In the case of motor vehicles, the invention relates more particularly to a device for transmitting and / or receiving radio frequency signals used in so-called hands-free access and / or starting systems.

  The invention also relates to a system for securing an enclosed space, in particular a motor vehicle, comprising such a device.

  In the automotive field, one aim of these hands-free security systems is to allow access (locking, unlocking or even automatic opening of the doors) and / or starting of a motor vehicle without a mechanical key or remote control.

  To do this, authentication of the user, wishing to access or start his vehicle, is carried out by dialogue between a management system on board the vehicle and an identifier (produced for example in the form of a badge) worn by the user.

  In these so-called hands-free systems, the communication between the management system and the identifier is carried out using different modes of communication of the radiofrequency signals according to the different functions to be performed.

  For access, for example, after detection of the approach or the presence of a user (carried out in a known manner and not described), the vehicle management system queries the identifier carried by the user in order to perform authentication. This interrogation, called hands-free interrogation, is carried out in a radiofrequency communication mode, for example at low frequency (LF) (frequency less than 150 kHz). Following the reception of this hands-free interrogation, the identifier emits a response in a radio frequency communication mode, for example at higher frequency of the order of 433 MHz (noted in the RF suite). If there is recognition of the identification code emitted by the identifier during its response, the vehicle management system controls the unlocking, or even the automatic opening, of the doors and the user can access his vehicle.

  This LF / RF data exchange mode can also be used for starting the vehicle, the exchange being, for example, initiated after pressing a start button.

  According to another possible mode for starting the vehicle, the user introduces the identifier into a device for reading the identifier arranged, for example, at the dashboard of the vehicle. This reading device comprises a transmission / reception member which will communicate in a particular mode with a transponder present in the identifier. The exchange of data, comprising identifier codes, between the transmission / reception unit and the transponder, makes it possible, by mutual recognition, to authenticate the identifier (and therefore the user) and, consequently, d '' authorize the vehicle to start. For authentication with a view to starting, the transmission / reception unit transmits, via an antenna which it presents, a LF (low frequency) signal for the attention of the transponder. Following the reception of this signal, the transponder uses the energy of the received signal and generates, by interaction with the magnetic field created by the emission of the transmission / reception member, a modification of the magnetic coupling between the transmitter / receiver and transponder.

  This change in coupling is detected at the transmission / reception unit which, if there is recognition of identifier codes exchanged during this communication, authorizes the vehicle to start. This mode of communication between the transponder and the transmission / reception member requires that the two elements be close to each other because the transponder does not have its own electrical supply: it operates by induction.

  This mode of transmission, known as transponder mode, allowing the authentication of the identifier, can also be used as a backup solution in the event of non-functioning of the identifier, for example, when the battery is to be changed. Indeed, if the handle, or a surface of the vehicle accessible from the outside by the user, integrates a transmission / reception organ, the approach of the identifier, integrating a transponder, near the organ of 'transmission / reception allows the authentication of the identifier code of the transponder present in this first and authorizes the unlocking of one or more doors.

  This dialogue, by exchange of radiofrequency signals, between the vehicle management system and the identifier, led the automotive suppliers to design and integrate devices for transmitting and / or receiving radiofrequency signals provided with antennas, at vehicle and identifier level.

  Thus, such devices are integrated into the vehicle, for example at the dashboard, near control elements such as handles, or even at an identifier reading device, but these 10 devices must also be positioned at the identifier to be able to receive information from the vehicle and send it back.

  Currently, the transmission and / or reception devices, comprising antennas, used in these hands-free systems are produced in different ways.

  Usually, each function, requiring the transmission and / or reception of a signal, has, in its associated application circuit, a dedicated antenna. Thus, each circuit has an antenna produced, for example, in the form of a support core surrounded by a metal coil. When these transmitting and / or receiving devices are produced in this way, the complete hands-free system may then have to integrate a large number of antennas.

  Thus, these antennas are arranged in large numbers at the vehicle, but some are also positioned at the identifier. These antennas have a non-negligible size generating integration difficulties, especially for the identifier.

  Furthermore, these antennas have, depending on their positioning, main axes oriented in very varied directions and this sometimes results in unwanted electromagnetic couplings.

  To solve the problem of the size of these antennas, the document DE-A-100 16 413 proposes, in the case of the equipment of a hands-free access system 30 integrated at the level of a vehicle, a device using a common antenna, formed of a single metallic winding, for two electronic circuits allowing the emission and / or the reception of frequency signals in two distinct modes of communication, namely, the reception of signals for hands-free identification from the user and reception of information for recognition in transponder mode. However, with this device, the antenna cannot be optimized for each of the two functions for which it is requested.

  Thus, in view of the above, it is often difficult to reduce the number of antennas to be integrated while retaining an optimization of their operating characteristics for different modes.

  For the reasons mentioned above, an object of the present invention is to provide a transmission and / or reception device, in particular for hands-free access and / or start-up systems, comprising a particular antenna element allowing reducing the number of antennas while optimizing their operation in relation to the functions ordered.

  This object is achieved according to the present invention, a first object of which is a transmission and / or reception device for a system for securing an enclosed space, said system comprising fixed equipment, linked to the enclosed space, as well a portable identification device and in which the fixed equipment and the portable identification device communicate by exchange of radio frequency signals, said transmitting and / or receiving device comprising: - an antenna element comprising an element support and a first metallic winding arranged around said support element, - a first electronic circuit connected to the antenna element and allowing communication between the fixed equipment and the portable identification device in a first mode of communication of the radio frequency signals , - a second electronic circuit connected to the antenna element and allowing communication between the fixed equipment and the ideation device ntification portable in a second mode of communication of radio frequency signals, characterized in that said transmitting and / or receiving device is located on the fixed equipment or on the portable identification device, and in that the element antenna comprises a second metal winding arranged around said support element and connected to the second electronic circuit, said second winding being used, alone or jointly with the first winding, to allow the exchange of radio frequency signals in the second communication mode.

  Thus, the transmitting and / or receiving device has an antenna element comprising, in addition to a first metal winding arranged on a support and connected to a first electronic circuit, a second metal winding arranged around the same l 'support element and connected to a second electronic circuit so that it is possible to optimize the operating characteristics of each of the windings compared to the communication mode used.

  A second object of the present invention is a system for securing an enclosed space, in particular a motor vehicle, comprising a transmission and / or reception device according to the present invention.

  The present invention also has particularly advantageous secondary characteristics which will be presented in the description which follows.

  The invention will be better understood during the detailed explanatory description of nonlimiting examples referring to the appended figures which represent: - Figure 1, a schematic representation, in top view, of a vehicle security system automobile comprising a transmission and / or reception device according to the invention; - Figure 2, a transmission and / or reception device according to a first embodiment of the invention and located on the portable identification device; - Figure 3, a transmission and / or reception device according to a second embodiment of the invention.

  FIG. 1 represents a schematic top view of a motor vehicle 1 comprising a transmitting and / or receiving device 10 according to the invention, forming part of a security system.

  The security system, called the hands-free system, comprises fixed equipment, linked to the confined space, and a portable identification device 3 produced in the form of an identifying badge.

  The fixed equipment comprises a cabin management unit 4 which communicates in particular with different members whose function is to provide the interface between the vehicle and a user. These members are, in the example presented, a device for reading the badge identifier 5 placed at the level of the vehicle dashboard, a member 6 for controlling the opening / closing of the boot placed at the boot, one or more handles 7a, 7b of the 10 side openings of the vehicle.

  These different organs 5, 6, 7 are connected to the management unit 4 via links, for example wired connections, 9a to 9d. Thus, the handles 7a and 7b are respectively connected to the management unit 4 by the links 9a and 9b.

  As also shown, the trunk control member 6 communicates with the management unit 4 via the link 9c and the reading device 5 is connected to the unit 4 by the link 9d.

  The portable identification device 3 is intended to be worn by a user and is presented, in FIG. 1, in two different situations. A first situation, in which the portable identification device 3, shown in solid lines, is located outside of the motor vehicle 1 for access to the vehicle and a second situation, in which the identification device portable 3, shown in dotted lines, is located inside the vehicle for starting the motor vehicle 1.

  In the example presented, the portable identification device 3 comprises a transmission and / or reception device 10 according to the invention.

  In the hands-free system presented, the transmission and / or reception device 10 of the identifier 3 communicates with transmission and / or reception devices conventionally produced (not shown) present at the interface members 5 , 6, 7, by means of radio frequency signals 17.

  This communication allows the management unit 4, by connection with the interface member, to authorize and control the implementation of the various functions requested by the user.

  In general, the useful functions for the user are in particular access to the vehicle or starting it.

  In the case of the vehicle access function, following the detection of the user near one or on a vehicle interface member, for example the handle 7b, a transmission device, present at the level of unit 4 of the vehicle, emits towards the badge identifying a hands-free interrogation. This hands-free interrogation, carried out according to a first radio frequency communication mode A, is received by a first electronic circuit of the transmission and / or reception device 10 of the invention. A response from the portable identification device 3, 10 comprising an identifier code, is then sent by an annex device which will not be described. If the identifier code, issued by the portable identification device 3, is recognized by the management unit 4, the latter authorizes the unlocking, or even the automatic opening, of at least one opening of the vehicle.

  In the case of the start function, for this example, the start authorization 15 is given following an interrogation, in a second communication mode B, called transponder mode, of the transponder (not shown) of the portable identification device 3 by the device for reading the badge identifying 5.

  This interrogation in transponder mode is received by a second electronic circuit, associated with the transponder, from the transmission and / or reception device 20 10 which induces in return, by modification of the magnetic coupling between the transmission / reception member and the transponder, a change of state of the transmission / reception unit (not shown) of the reading device 5.

  FIG. 2 shows a transmission and / or reception device according to a first embodiment of the invention.

  In the example presented, the transmission and / or reception device 10 is located in the portable identification device 3. It comprises an antenna element 11 which is produced in the form of a support element 12 and d 'a first metal winding 13 arranged around the support element. The device 30 for transmitting and / or receiving 10 also comprises a first electronic circuit 15 and a second electronic circuit 16, both connected to the antenna element 11.

  As shown, the first electronic circuit 15 is connected to the first winding 13.

  According to the invention, the antenna element 11 has a second winding 14 also arranged around the support element 12, and connected to the second electronic circuit 16.

  Thus, there is a support element 12 on which are arranged, along the longitudinal axis XX 'of the support element 12 and adjacent, two windings 13 and 14 connected respectively to the first electronic circuit 15 and to the second electronic circuit 16.

  To achieve tuning of each of the antennas formed respectively by the first winding 13 on the support element 12 and by the second winding 14 on the support element 12, tuning capacities 18 and 19 are provided for this purpose.

  Depending on whether the antennas formed will work in transmission or reception, the tuning capacities 18, 19 will be connected to their respective antenna in series or in parallel.

  In the example described, the support element 12 is a magnetically conductive ferrite core whose role is to amplify the magnetic couplings, but it is also possible to use another type of support 20 such as, for example, a plastic support to produce air coils.

  The first electronic circuit 15, connected to the first winding 13, allows communication between the vehicle (not shown in FIG. 2) and the portable identification device 3 according to the first communication mode A, hands-free mode, of the radio frequency signals 17 .

  According to the invention, the second electronic circuit 16, connected to the second winding 14, allows communication between the vehicle (not shown in FIG. 2) and the portable identification device 3 according to the second communication mode B, transponder mode, of the radio frequency signals 17.

  The electronic circuits 15, 16, the tuning capacities 18, 19 as well as the length and the diameter of the metal wire of the windings 13, 14 are studied so as to optimize the operation of each antenna, formed of a winding 13, 14 arranged around the support element 12, with respect to the communication mode associated with it.

  Thus, during hands-free interrogation by the vehicle, the first winding 13 arranged on the support element 12 forms an antenna shaped to receive this hands-free interrogation associated with communication mode A. During interrogation in transponder mode by the device for reading the portable identifier 5 (of FIG. 1), the second winding 14 arranged on the support element 12 forms an antenna shaped to receive this transponder interrogation and to induce in return a transponder "response". This reception of the transponder interrogation and this induction of the transponder "response" are associated with the communication mode B. Each winding is therefore used independently with its associated circuit to work in the first or in the second communication mode. The reception of information according to the different modes of communication can therefore take place at the same time and the two circuits 15 can work in parallel without interaction.

  In conclusion, the antenna element 11 therefore has two antennas each formed by a winding 13, 14 arranged on the support element 12, which are mechanically and electrically independent, while presenting a reduced bulk due to the pooling of the support element 12.

  FIG. 3 shows a device for transmitting and / or receiving according to a second embodiment of the invention in which the second winding 14 is used jointly with the first winding 13 to allow the exchange of radio frequency signals in the second mode of communication B. In the transmission and / or reception device 10 according to this second embodiment, the antenna element 11 also comprises a second metal winding 14.

  This second metal winding 14 is connected on the one hand, to the second electronic circuit and on the other hand, to the first winding 13. In the example 30 presented, the first winding 13 and the second winding 14 are disposed adjacent to the the support element 12 and the second winding 14 is formed in the continuity of the first winding 13 so that the two windings 13, 14 are arranged in series.

  The two windings 13 and 14 are connected in series across the second electronic circuit so that the second electronic circuit 16 uses the two windings 13 and 14 for communication in the second communication mode.

  Thus, the first winding 13 arranged on the support element 12, forms a first antenna shaped to receive, for example, a hands-free interrogation, associated with the communication mode A and the assembly in series of the first and second windings 13 and 14 arranged on the support element 12 forms a second antenna shaped for a transponder communication mode, associated with the communication mode B. Tuning capacities 18, 19 are also provided for tuning the first and second antennas.

  Depending on the power and / or the frequency range of the radiofrequency signals emitted and intended to be received, the transmitting and / or receiving device 10 automatically detects that it is a hands-free interrogation or a transponder interrogation for communication in transponder mode. Thus, depending on whether it is a hands-free interrogation or a transponder interrogation, reception will be carried out by the first or the second antenna.

  The two electronic circuits 15 and 16 remain electrically independent in terms of operating frequency and inductance, which also makes it possible to optimize their performance when they are connected with their respective antenna.

  Alternatively and to further reduce the size of the antenna element 11, the first winding 13 and the second winding 14 can be arranged superimposed on the support element 12 without this having too much influence. important the operating characteristics.

  In the same way, the transmission / reception device forming the subject of the invention can be arranged at the level of the motor vehicle 1. In particular, when the transmission and / or reception device is arranged at the level of a handle of the vehicle, it can be used as a backup solution for the authentication of the portable identification device. In this embodiment, the first electronic circuit is used for hands-free transmission in the direction of the identifying badge and the second circuit belongs to a transmission / reception unit and allows communication in transponder mode with the transponder present in the device. portable identification.

  The transmitting and / or receiving device can therefore be located on fixed equipment placed at vehicle level and / or on the portable identification device forming an identifying badge.

  Depending on the desired performance of the windings arranged on the support element, the support element can have different shapes and in particular a form of bar, as shown in FIGS. 2 and 3, or even a T shape. Furthermore, as we l 'have described, the support of the antenna element is made in the form of a ferrite rod, but it is also possible to use another type of support such as, for example, a plastic support to make air coils or antennas.

  Thanks to the invention, this arrangement of the two windings on the same support is particularly advantageous because it makes it possible to produce the assembly in the form of a single component and allows automation of the assembly process.

  Thus, according to the invention, a transmission and / or reception device has been produced having a single support element for several windings and in which the windings are used alone or jointly in connection with independent electronic circuits to ensure the exchange. of radio frequency signals, with one or more external devices, in several communication modes.

Claims (11)

  1. Transmitting and / or receiving device for a system for securing an enclosed space, said system comprising fixed equipment (4, 5, 6, 7), linked to the confined space, as well as a portable identification device (3) and in which the fixed equipment (4, 5, 6, 7) and the portable identification device (3) communicate by exchange of radio frequency signals (17), said transmission device and / or reception comprising: - an antenna element (11) comprising a support element (12) and a first metal winding (13) arranged around said support element, - a first electronic circuit (15) connected to the element d antenna (11) and enabling communication between the fixed equipment (4, 5, 6, 7) and the portable identification device (3) in a first mode of communication (A) of the 15 radio frequency signals (17), - a second electronic circuit (16) connected to the antenna element (11) and allowing communication between the equipment fixed (4, 5, 6, 7) and the portable identification device (3) in a second mode of communication (B) of the radio frequency signals (17), characterized in that said transmission and / or reception device is located on the fixed equipment (4, 5, 6, 7) or on the portable identification device (3), and in that the antenna element (11) comprises a second metal winding (14) arranged around said support element (12) and connected to the second electronic circuit (16), said second winding being used, alone or jointly with the first winding (13), to allow the exchange of radio frequency signals (17) in the second mode of communication (B).   2. Transmitting and / or receiving device according to claim 1, characterized in that the first (13) and the second (14) windings are arranged on the support (12) along the same axis (XX ').   3. Transmitting and / or receiving device according to claim 1 or 2, characterized in that the first (13) and the second (14) windings are arranged adjacent to the support element (12).   4. Transmitting and / or receiving device according to claim 1 or 2, characterized in that the first (13) and the second (14) windings are arranged superimposed on the support element (12).   5. Transmission and / or reception device according to any one of claims 1 to 4, characterized in that the second winding (14) is formed in the continuity of the first winding (13) so that the first ( 13) and the second (14) winding are arranged in series.   6. Transmission and / or reception device according to claim 5, 15 characterized in that the first (13) and the second (14) windings are connected in series across the terminals of the second electronic circuit (16).   7. Transmission and / or reception device according to any one of claims 1 to 6, characterized in that it comprises a tuning capacity (18, 20 19) connected to the terminals of each winding (13, 14 ).   8. Transmitting and / or receiving device according to any one of claims 1 to 7, characterized in that the support element (12) is formed by a ferrite bar.   9. Transmitting and / or receiving device according to any one of claims 1 to 8, characterized in that the first mode of communication (A) between the fixed equipment (4, 5, 6, 7) and the portable identification device (3), is a hands-free communication mode. 30 10. Transmission and / or reception device according to any one of claims 1 to 9, characterized in that the second mode of communication (B), between the fixed equipment (4, 5, 6, 7) and the portable identification device (3) is a transponder communication mode.   11. System for securing an enclosed space, in particular a motor vehicle, characterized in that it comprises a transmitting and / or receiving device (10) as claimed in claims 1 to 10.