Approach detection device

Abstract

The invention proposes a detection device (D) for the approach of a user's body part or a user's portable device (200), intended to be carried in a motor vehicle (V) comprising: a near-field communication antenna (A1) configured to emit signals at a high frequency selected between 3 and 30 MHz, said antenna (A1) being capable of detecting the approach of a user's portable device (200) and of communicating in the near field with said user's portable device (200), said antenna (A1) comprising at least one winding (E1, E2, E3) which extends continuously in the form of a set of rods (O1, O2.Oi, N1, N2…Ni) in the shape of a comb such that said antenna (A1) is capable of generating a capacitance variation upon approach to a user's body part, control means (10) of said antenna (A1), and measurement means (M2) of an impedance variation of said antenna (A1) generated by the capacitance variation. Figure for the abbreviation: Fig. 1.

Description

Title of the invention: Approach detection device Technical field

[0001] The invention relates to an approach detection device. The invention applies more particularly to the detection of the approach of a hand and / or a smart mobile phone (called: "smartphone" in English) towards a bodywork element of a motor vehicle such as for example a handle of an opening or an opening pillar (door or trunk) in order to unlock the opening or towards an inductive mobile phone charger, of the WPC charger type which is found on board motor vehicles in order to charge the mobile phone. Prior art

[0002] Nowadays, vehicle door handles are equipped with devices for detecting the approach of a user's hand or a smart mobile phone. The detection of approach and / or contact of a user's limb, for example a user's hand on the handle coupled with the recognition of a user's portable equipment, for example a "hands-free" electronic badge for remote access control, carried by this user, allows the locking and unlocking of the vehicle's openings. Thus, when the user, wearing the corresponding electronic badge and identified by the vehicle, wishes to unlock the vehicle, he touches the vehicle's door handle and the latter then activates an electric strike at the lock of the opening or openings of the vehicle which is / are then automatically unlocked.By approaching or pressing a specific location on the vehicle door handle, called the "unlocking zone", the door (or alternatively all openings) is (are) unlocked (unlocked) without any further action from the user. Conversely, when the user, still wearing the necessary badge and identified by the vehicle, wishes to lock his vehicle, he closes the door of his vehicle and momentarily presses another specific location on the handle, called the "locking zone". This action automatically locks the vehicle's openings.

[0003] These devices for detecting the approach of a hand for unlocking / locking generally comprise two capacitive sensors, in the form of two electrodes electrically connected to a printed circuit, integrated in the door handle each in a specific locking or unlocking zone. Generally, one electrode is dedicated to each zone, that is to say one electrode is dedicated to detecting the approach and / or contact of the user's hand in the zone of locking and an electrode is dedicated to detecting the approach and / or contact of the user's hand in the unlocking zone.

[0004] This device for detecting the approach of a hand further comprises a radio frequency antenna, generally LF (English abbreviation for "Low Frequency") but this antenna can also be a high or ultra high frequency antenna, of the UWB, BLE, Wifi, 4G, 5G type... or of the NFC "Near field communication" type in English or near field communication, that is to say any antenna or communication device allowing an identifier to be exchanged with the mobile phone in order to authenticate it.

[0005] The detection device also comprises an electronic control unit of the vehicle (ECU: English abbreviation for "Electronic Control Unit") which receives a presence detection signal from the capacitive sensors. The electronic control unit of the vehicle has, beforehand, identified the user as being authorized to access this vehicle, or alternatively, following the reception of this presence detection signal, it carries out this identification. To do this, it sends, via the radiofrequency antenna, an identification request to the badge (or remote control) carried by the user. This badge sends in response, by RF (radio frequency) waves or NFC, or UWB, or Wifi, or BLE... its identification code to the electronic control unit of the vehicle. If the electronic control unit recognizes the identification code as the one authorizing access to the vehicle, it triggers the locking / unlocking of the door (or all the openings).If, on the other hand, the electronic calculator has not received an identification code or if the identification code received is incorrect, locking or unlocking does not take place.

[0006] When it comes to detecting the approach of a smartphone, the detection device instead comprises an NFC reader ("Near Field Communication"), known per se, in order to detect by radiofrequency exchange at 23.6 MHz, the presence of a nearby smartphone, also equipped with near field communication means and to be able to receive the identifier of said telephone in order to ensure that it is recognized as being paired with the vehicle and thus proceed with locking / unlocking. This NFC reader is connected to a dedicated microcontroller.

[0007] Such vehicles are therefore equipped with door handles comprising a detection device equipped with a radiofrequency antenna, two electrodes connected to a first capacitive detection microcontroller dedicated to detecting the approach of a hand and an NFC reader, itself connected to a second microcontroller dedicated to the detection by NFC of a smart mobile phone, the whole being integrated into a printed circuit.

[0008] However, the integration of all these electronic components poses a problem of space requirement in the door handle as well as a significant additional cost. In addition, NFC detection is not reliable when mobile phones contain very little metal, for example plastic cases or when the portable access device is a "tag" in English, that is to say a badge made almost entirely of plastic.

[0009] The invention therefore proposes a detection method and an associated device making it possible to overcome the drawbacks of the prior art. More particularly, the invention proposes a simple and inexpensive device making it possible to detect both the approach of a hand and the approach of a smartphone using only NFC technology, i.e. near field communication. Statement of the invention

[0010] The invention relates to a device for detecting the approach of a member of a user's body or of a user's portable equipment, intended to be installed in a motor vehicle, the device being remarkable in that it comprises: a. a near-field communication antenna configured to transmit signals at a high frequency selected between 3 and 30 MHz, said antenna being adapted to detect the approach of a user's portable equipment and to communicate in the near field with said user's portable equipment, said antenna comprising at least one winding which extends continuously in the form of a set of comb-shaped rods such that said antenna is adapted to generate a variation in capacitance upon approach of a member of a user's body, b. Means of controlling said antenna, c. Means for measuring a variation in impedance of said antenna generated by the variation in capacitance.

[0011] In a preferred embodiment of the device according to the invention, the winding delimits a perimeter inside which said antenna extends continuously in the form of a set of comb-shaped rods.

[0012] In a particular case, the perimeter being rectangular, the rods are in the form of copper tracks perpendicular to a length or a width of the perimeter.

[0013] The stems may be identical to each other.

[0014] Said antenna may comprise rods on two opposite sides of the perimeter.

[0015] The means for measuring an impedance variation can be in software form and measure any variation in phase, current or voltage coming from the antenna.

[0016] The invention also relates to any vehicle door handle remarkable in that it comprises a detection device according to any one of the characteristics listed above.

[0017] The invention also relates to any inductive charger for portable user equipment, remarkable in that it comprises a detection device according to any one of the characteristics listed above.

[0018] Finally, the invention also applies to any motor vehicle notable in that it comprises a detection device according to any one of the characteristics listed above. Brief description of the drawings

[0019] Other characteristics and advantages of the invention will become apparent from reading the description which follows. This is purely illustrative and must be read in conjunction with the appended drawings in which:

[0020] [Fig.l]: [Fig.l] is a schematic representation of the approach detection device according to the invention,

[0021] [Fig.2]: [Fig.2] is an electronic diagram of the modified near-field communication antenna according to the invention,

[0022] [Fig.3]: [Fig.3] is a schematic representation of a vehicle door handle comprising the detection device according to the invention;

[0023] [Fig.4]: [Fig.4] is a schematic representation of an inductive charger for portable user equipment comprising the detection device according to the invention,

[0024] [Fig.5]: [Fig.5] is a schematic representation of a preferred embodiment of the detection device according to the invention,

[0025] [Fig.6]: [Fig.6] is a schematic representation of a third embodiment of the detection device according to the invention,

[0026] [Fig.7]: [Fig.7] is a schematic representation of the means for controlling the antenna of the detection device according to the invention Description of the embodiments

[0027] The device for detecting the approach of a member of a user and a

[0028] portable user equipment is illustrated in [Fig.2].

[0029] The device D comprises a near-field communication antenna Al,

[0030] (also called NFC in English “Near Field Communication”) between 3 and 30 MHz, by example at 23.56 MHz, capable of detecting and communicating with a user's portable equipment, for example a smart mobile phone or a badge ("also called "tag" in English) equipped with NFC communication technology. This type of antenna NFC Al is associated with microprocessor and software or other electronic means in order to be able to exchange data with the user's portable equipment.

[0031] The detection of approach of a user's portable equipment towards the detection device

[0032] D is carried out by measuring the variation in impedance of the NFC antenna A1. This is known to those skilled in the art and will not be detailed further here.

[0033] The invention proposes that the antenna Al comprises at least one winding El, E2, E3 and that it extends continuously in the form of at least one set of comb-shaped rods O1, O2.. .Oi, and NI, N2.. .Ni, connected to control means 10.

[0034] "Rods" are copper-shaped tracks of predetermined width, for example flattened wires or copper strips, which are connected to each other and which constitute incursions, protrusions, outgrowths, extensions of the NFC Al antenna itself consisting of a copper track.

[0035] The NFC antenna Al may comprise a plurality of windings El, E2, E3 of square, rectangular, oval or round shape.

[0036] In Figures 1, 5 and 6, solely for explanatory purposes, the windings E1, E2, E3 of the NFC antenna A1 are three in number and are shown in rectangular shape without this being limiting.

[0037] In [Fig.l], the NFC antenna Al comprises three windings El, E2, E3, connected to control means 10. The NFC antenna Al is extended by means of two connections J1, J2 connected to the control means 10, forming two sets of rods O1, O2, ...Oi and NI, N2, ...Ni. In this example, the rods O1, O2, ...Oi or NI, N2, .. .Ni. of each respective set are identical to each other and all the rods of the two sets are parallel to each other.

[0038] Of course, the rods 01, 02, ...Oi and NI, N2, ...Ni can be inclined along an axis parallel to a length or a width of a rectangular winding of the NFC antenna Al, said rods can be of different widths between them, and / or of different geometry between them, and / or with different width spacings between them.

[0039] In a preferred embodiment of the detection device D according to the invention, but which is in no way limiting, the winding(s) El', E2', E3' delimit(s) a perimeter inside which said NFC antenna Al' extends continuously in the form of at least one set of comb-shaped rods, in this example, two sets of rods O1', O2', O3'..Oi', and NI', N2', N3'..Ni' each of the sets being comb-shaped, this is illustrated in [Fig.5].

[0040] In [Fig.5], according to a preferred embodiment of the invention, inside a rectangular perimeter defined by the windings El' E2', E3' of the NFC antenna Al'; the NFC antenna Al' comprises two sets of rods O1', O2'...Oi'; or NI', N2', N3'...Ni' each resembling a comb. Each of the two sets O1', 02' ...0i' ; or NI', N2', N3'...Ni' is perpendicular to a length of the perimeter and the two sets 01', 02'...OM' ; or NI', N2', N3'...Ni' are each located on opposite sides of the perimeter. Each rod 01', 02', ...Oi' ; of the first set is intercalated with a rod of the second set NI', N2', N3'...Ni'.

[0041] In order to detect the approach of a user's hand, the detection device D further comprises means 10 for controlling the NFC antenna A1, capable of measuring a variation in impedance of said NFC antenna A1.

[0042] The control means 10 are illustrated in [Fig.7]. Said control means 10 comprise: a voltage source Vc, an NFC driver for near-field communication (called NFC “driver” in English) Ml connected to a microcontroller p then an adaptation circuit M3 comprising at least one filter and means for adjusting the impedance and frequency of the NFC antenna A1. The control means 20 also comprise a receiver circuit Rx dedicated to receiving data from the NFC antenna A1

[0043] Said control means 10 of an NFC antenna are known to those skilled in the art and will not be detailed further here.

[0044] According to the invention, the control means 10 also comprise impedance measuring means M2 capable of measuring any variation in impedance of the NFC antenna A1 thus modified as detailed below.

[0045] The means for measuring the impedance variation M2 are for example included in the NFC driver M1 and are presented in software form, and measure any variation in the phase, current or voltage coming from the NFC antenna A1 in order to deduce therefrom a variation in the impedance of the NFC antenna A1.

[0046] The NFC antenna thus modified compared to the prior art, thanks to the sets of rods, has a parasitic capacitance C2 significantly higher than the NFC antenna of the prior art.

[0047] Said parasitic capacitance C2 thus generated is then measurable and can be exploited in an ingenious manner in order to detect the approach of a member of the user's body, for example the approach of a hand of the user towards the detection device D.

[0048] Thus, the NFC antenna Al according to the invention is capable of generating a variation in capacitance upon approaching a member of a user, measurable by means of the measurement of a variation in impedance.

[0049] In [Fig.2] is shown schematically the equivalent electrical circuit of

[0050] the NFC antenna Al thus modified. The circuit is an RLC circuit "Resistance, inductance and capacitance" consisting of a first branch comprising a resistance RI, connected to an inductance Ll, a second branch comprising a capacitance Cl, a third branch comprising a parasitic capacitance C2, all three branches being connected in parallel. The parasitic capacitance C2, is generated thanks to the rods of the modified NFC Al antenna and is of greater value than the capacitance Cl which represents the capacitance created by the windings El, E2, E3 of the NFC Al antenna

[0051] The RLC circuit thus formed is sensitive not only to the approach of a user's portable equipment but also to the approach of a member of the user's body, for example his hand.

[0052] Indeed, when approaching a user's portable equipment, an inductive coupling (between the NFC antenna of the user's portable equipment and the NFC antenna A1 of the detection device D) and a capacitive coupling (between the rods of the modified NFC antenna A1 and the metal parts of the portable equipment) are created between said equipment and the detection device D, varying the value of each of the three parameters, i.e. the value of the resistance RI, the value of the parasitic capacitance C2 and the value of the inductance L1.

[0053] The variation of these three parameters RI, L1, C2 induces a notable change in the impedance of the antenna, i.e. a “mismatching” in English or mismatching in French, which is measured by the impedance measuring means M2.

[0054] Similarly, when a user's hand approaches the detection device D, a capacitive coupling is created between the user's portable equipment and the NFC antenna A1 modified according to the invention (in this case with the conductive surface of the rods) causing the value of the parasitic capacitance C2 to vary. The impedance of the NFC antenna A1 is then modified by this variation in capacitance C2, and is measured by the impedance measuring means M2.

[0055] In [Fig.6] a third embodiment of the invention is illustrated, in which the rods of the NFC antenna Al” are only two in number 01”, NI”, parallel to each other and connected to the NFC antenna Al at the level of two connections J1”, J2” connected to the control means 10” and to the input of the measuring means M2.

[0056] In [Fig. 3] is shown a handle P of a vehicle door V comprising the detection device D according to the invention. The NFC antenna A1 is located on a printed circuit 100 included in the handle P which also comprises the control means 10.

[0057] The detection device D thus makes it possible to detect the approach of a user's portable equipment 200 and the approach of a hand M near the handle P in order to unlock the door.

[0058] In [Fig.4] is shown an inductive charger C of portable user equipment 200 comprising the detection device D according to the invention.

[0059] The charger C comprises a first printed circuit 101 on which is located for example a ferrite F, itself located below a charging coil Bl. Above the charging coil Bl, there is a second printed circuit 100 comprising the control means 10, on which the NFC antenna Al modified according to the invention is engraved.

[0060] Similarly, the detection device D according to the invention makes it possible to detect the approach of a user's hand as well as the approach of a user's portable equipment 200 near or towards the charger C.

[0061] The invention therefore ingeniously makes it possible, by modifying the NFC antenna, to be able to achieve not only the detection of the approach of a user's portable equipment but also the detection of the approach of a user's hand by the judicious use of the parasitic capacitance of the antenna, the value of which is increased by the modification of the layout of the NFC antenna comprising comb-shaped protrusions generating said increase in parasitic capacitance. This invention is all the more remarkable since the impedance measurement is sufficient to detect the approach of the hand and the approach of a user's portable equipment, which was not possible in the prior art.

Claims

Claims

1. Device (D) for detecting the approach of a member of a user's body or of a user's portable equipment (200), intended to be embedded in a motor vehicle (V), characterized in that it comprises: a. a near-field communication antenna (Al) configured to emit signals at a high frequency selected between 3 and 30 MHz, said antenna (Al) being capable of detecting the approach of a user's portable equipment (200) and of communicating in the near field with said user's portable equipment (200), said antenna (Al) comprising at least one winding (El, E2, E3) which extends continuously in the form of a set of rods (01, 02..Oi, NI, N2...Ni) in the form of a comb such that said antenna (Al) is capable of generating a variation in capacitance upon approach of a member of a user's body, b. control means (10) of said antenna (Al) c.means (M2) for measuring a variation in impedance of said antenna (Al) generated by the variation in capacitance.

2. Detection device (D) according to the preceding claim, characterized in that the winding (El, E2, E3) delimits a perimeter inside which said antenna (Al) extends continuously in the form of a set of rods (01, 02.. .Oi, NI, N2.. .Ni) in the form of a comb.

3. Detection device (D) according to the preceding claim, characterized in that the perimeter being rectangular, the rods (01, 02.. .Oi, NI, N2.. .Ni) are in the form of copper tracks perpendicular to a length or a width of the perimeter.

4. Detection device (D), according to any one of claims 2 to 3, characterized in that said antenna (Al) comprises rods (01, 02...Oi, NI, N2...Ni) on two opposite sides of the perimeter.

5. Detection device (D) according to any one of the preceding claims, characterized in that the rods (01, 02...Oi, NI, N2... Ni) are identical to each other.

6. Detection device (D) according to any one of the preceding claims, characterized in that the means (M2) for measuring a variation in impedance are in software form and measure any variation in phase, current or voltage coming from the antenna (Al).

7. Vehicle door handle (P) (V) characterized in that it comprises a detection device (D) according to any one of claims 1 to 6.

8. Inductive charger (C) for portable user equipment (200), characterized in that it comprises a detection device (D) according to any one of claims 1 to 6.

9. Motor vehicle (V), characterized in that it comprises a detection device (D) according to any one of claims 1 to 6.

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