System for detecting approach and/or contact of a user and ultra high frequency communication with a portable user apparatus

Abstract

Disclosed is a system for detecting approach and/or contact of a user and Ultra High Frequency communication with a portable user apparatus, intended to be embedded on board an automotive vehicle, the system including: a device for detecting approach and/or contact, including a sensor for detecting approach and/or contact and an electronic control unit; a conducting metal surface, suitable for the conduction of electric charges; and a communication device, including an Ultra High Frequency antenna emitting an electromagnetic field at an Ultra High Frequency wavelength, and a management unit for managing the emission and reception of data of the antenna. The conducting metal surface takes the form of a continuous path including a plurality of meanders spread over a length at least equal to:
L=λ/6
wherein L is a total length of the meanders, and λ is a wavelength of the Ultra High Frequency antenna.

Claims

1. A system (20) for detecting approach and/or contact of a user and Ultra High Frequency communication with a portable user apparatus, intended to be embedded on board an automotive vehicle, said system comprising: a device for detecting the approach and/or contact, comprising a sensor for detecting the approach and/or contact and an electronic control unit (61), a conducting metal surface (60), suitable for the conduction of electric charges, a communication device, comprising an Ultra High Frequency antenna (50) emitting an electromagnetic field at an Ultra High Frequency wavelength (λ), and a management unit (51) for managing the emission and reception of data of said antenna, the presence of this conducting metal surface disturbing an operation of the Ultra High Frequency antenna (50) and rendering the Ultra High Frequency communication inoperative in certain zones (Zj) around the system (20), wherein the conducting metal surface (60) takes the form of a continuous path comprising a plurality of meanders (M) spread over a length (L) at least equal to:
L=λ/6 with: L being a total length of the plurality of meanders, and λ being a wavelength of the Ultra High Frequency antenna.

2. The system (20) as claimed in claim 1, wherein at least part of the plurality of meanders (M) takes the form of slots, or of sawteeth, or of sinusoid.

3. The system (20) as claimed in claim 1, wherein the UHF antenna (50) being defined by a longitudinal axis (XX′) and a transverse axis (YY′), wherein at least part of the plurality of meanders (M) is oriented along an axis parallel to the longitudinal axis (XX′), or parallel along the transverse axis (YY′), or along an inclined axis with respect to one or the other of the axis parallel to the longitudinal axis (XX′) or to the transverse axis (YY′).

4. The system (20) as claimed in claim 1, wherein the sensor for detecting approach and/or contact is a capacitive sensor and that the conducting metal surface (60) is an electrode of said sensor.

5. The system as claimed in claim 1, wherein the conducting metal surface (60′) is an electrical ground plane (100).

6. A handle (P) of automotive vehicle door (1), comprising the system (20) as claimed in claim 1.

7. An automotive vehicle, comprising the system (20) as claimed in claim 1.

8. The system (20) as claimed in claim 2, wherein the UHF antenna (50) being defined by a longitudinal axis (XX′) and a transverse axis (YY′), wherein at least part of the plurality of meanders (M) is oriented along an axis parallel to the longitudinal axis (XX′), or parallel along the transverse axis (YY′), or along an inclined axis with respect to one or the other of the axis parallel to the longitudinal axis (XX′) or to the transverse axis (YY′).

9. The system (20) as claimed in claim 2, wherein the sensor for detecting approach and/or contact is a capacitive sensor and that the conducting metal surface (60) is an electrode of said sensor.

10. The system (20) as claimed in claim 3, wherein the sensor for detecting approach and/or contact is a capacitive sensor and that the conducting metal surface (60) is an electrode of said sensor.

11. The system (20) as claimed in claim 8, wherein the sensor for detecting approach and/or contact is a capacitive sensor and that the conducting metal surface (60) is an electrode of said sensor.

12. The system as claimed in claim 2, wherein the conducting metal surface (60′) is an electrical ground plane (100).

13. The system as claimed in claim 3, wherein the conducting metal surface (60′) is an electrical ground plane (100).

14. The system as claimed in claim 8, wherein the conducting metal surface (60′) is an electrical ground plane (100).

15. A handle (P) of automotive vehicle door (1), comprising the system (20) as claimed in claim 2.

16. A handle (P) of automotive vehicle door (1), comprising the system (20) as claimed in claim 3.

17. A handle (P) of automotive vehicle door (1), comprising the system (20) as claimed in claim 4.

18. A handle (P) of automotive vehicle door (1), comprising the system (20) as claimed in claim 5.

19. An automotive vehicle, comprising the system (20) as claimed in claim 2.

20. An automotive vehicle, comprising the system (20) as claimed in claim 3.

Description

(1) Other subjects, characteristics and advantages of the invention will become apparent on reading the description which follows by way of nonlimiting example and on examining the appended drawings, in which:

(2) FIG. 1, already explained previously, schematically represents a sectional view of a system according to the prior art comprising a device for detecting approach and/or contact and a UHF communication device integrated into an automotive vehicle door handle,

(3) FIG. 2 already explained previously, schematically represents a view from above of the system 2 illustrated in FIG. 1,

(4) FIG. 3 schematically represents a sectional view of a system comprising a device for detecting approach and/or contact and a UHF communication device integrated into an automotive vehicle door handle, according to the invention,

(5) FIG. 4a schematically represents a view from above of the system illustrated in FIG. 3,

(6) FIG. 4b schematically represents a view from below of the system illustrated in FIG. 3,

(7) FIGS. 5a to 5c schematically represent embodiments of the detection system according to the invention.

(8) As described previously, the detection system 2 of the prior art, for example integrated into a vehicle door 1 handle P, comprising a conducting metal surface, such as an electrode 6, situated in proximity to a UHF Ultra High Frequency antenna 5, such as an antenna of Wifi, Blue tooth or other type, does not make it possible to communicate at Ultra High Frequency with a portable user apparatus in a robust manner. The presence of this conducting metal surface disturbs the operation of the UHF antenna 5 and renders UHF communication inoperative in certain zones Zj around the handle P.

(9) By UHF, Ultra High Frequency, is also meant Wifi or other communication of frequency greater than 3 GHz.

(10) The invention proposes a system 20, illustrated in FIGS. 3, 4a, 4b, 5a to 5c making it possible to alleviate the drawbacks of the prior art.

(11) According to the invention, the system 20 for detecting approach and/or contact of a user and ultra-high frequency communication with a portable user apparatus, comprises as in the prior art: a device for detecting approach and/or contact of a user, comprising a sensor for detecting approach and/or contact and an electronic control unit 610. a conducting metal surface 60, a UHF communication device, comprising an ultra-high frequency antenna 50 and a management unit 510 for managing the emission and reception of the data at UHF by way of said antenna.

(12) In the case where the system 20 comprises a device for detecting approach and/or contact such as a capacitive sensor, the conducting metal surface 60 can consist of a locking or unlocking electrode 60 of said sensor.

(13) In the case where the system 20 comprises a device for detecting approach and/or contact in the form of a Hall-effect sensor or an inductive sensor, the conducting metal surface 60 can consist of a ground plane 100 integrated into a printed circuit 30 (cf. hereinbelow).

(14) By “conducting metal surface” is meant any surface allowing the conduction of electric charges.

(15) The management unit 510 for managing the emission and the reception of the data at UHF comprises in a manner known per se, an emitter receiver and an adaptation element for adapting the frequency of said UHF antenna 50, in the form of an inductor or capacitor for example and linked to said UHF antenna 50.

(16) The electronic control unit 610 takes the form of a microcontroller 610 controlling the sensor for detecting approach and/or contact, electrically powering the sensor and validating the detection of approach and/or of contact of the sensor.

(17) The electronic control unit 610, the conducting metal surface 60, the antenna 50 and the management unit 510 are in a preferential, but nonlimiting, manner situated on a printed circuit 30.

(18) The UHF antenna 50 can also be sited remotely from the printed circuit 30, and linked electrically to the management unit 510, the latter being situated on the printed circuit 30.

(19) The invention proposes that the conducting metal surface 60 take the form of a continuous path exhibiting a plurality of meanders M such that the total length L of the meanders is greater than:

(20) $L\ge \frac{\lambda }{6}$
With: L: total length of the surface on which the meanders are situated (mm). λ: wavelength of the ultra-high frequency (mm).

(21) The applicant has indeed noted that, by modifying the shape of the conducting metal surface which was, according to the prior art, generally rectangular (cf. reference 6 in FIG. 2), into a continuous path exhibiting a plurality of meanders M (cf. FIGS. 4a, and FIGS. 5a to 5c) spread over a length L at least equal to a sixth of the wavelength of the UHF antenna 50, the electromagnetic field of said UHF antenna 50 was no longer impacted by the presence of said surface. The radiation zone Z of the electromagnetic field is then homogeneous around the handle P, this is illustrated in FIGS. 3 and 4a.

(22) By “continuous path” is meant a path not exhibiting any interruption of material or any cut and allowing the current to flow from one end of the path to the other opposite end of the path.

(23) By “meanders” M is meant any shape exhibiting a turning, a curve or an outbound- inbound portion, or a change of direction in the continuous path.

(24) Thus, part of the plurality of meanders M can take the form of slots, regular (cf. FIG. 4a) or irregular (FIG. 5), of sawteeth (FIG. 5c), of a sinusoid (not represented), or of a combination of these stated shapes.

(25) The meanders can all be identical (cf. FIGS. 4a, 5c), or exhibit mutual differences (cf. FIGS. 5a and 5b).

(26) In FIGS. 3 and 4a are represented a sectional view and a view from above of the system 20 according to the invention.

(27) In FIG. 4a, the conducting metal surface, in this example, consisting of the electrode 60 of a capacitive sensor, takes the form of a continuous path consisting of a succession of meanders M in the form of slots, of length L greater than

(28) $\frac{\lambda }{6}.$
The electrode 60 is linked to the control unit 610 and is situated on the printed circuit 30, on which are also situated the HF antenna 50 linked to the management unit 510.

(29) The UHF antenna 50 is defined according to two axes, a longitudinal axis XX′ and a transverse axis YY′, which are mutually perpendicular and cut one another at a center 0 of said antenna.

(30) In FIG. 4a, the meanders are oriented along an axis parallel to the transverse axis YY′.

(31) The radiation zone Z around the system 20 is homogeneous and does not exhibit any null, or any zone of absence of radiation as in the prior art.

(32) In FIGS. 5a to 5c, other shapes of meanders M are represented.

(33) In FIG. 5a, the meanders M take the form of non-mutually symmetric slots, of mutually variable lengths and widths, oriented along an axis parallel to the transverse axis YY′.

(34) In FIG. 5b, the meanders take the form of non-symmetric slots, oriented along an axis parallel to the longitudinal axis XX′.

(35) In FIG. 5c, the meanders M take the form of mutually symmetric sawteeth, oriented along a transverse axis YY′. The sawteeth may also not exhibit any mutual symmetry.

(36) Of course, other shapes of meanders M are conceivable, for example in the form of a sinusoid.

(37) Other orientations of the meanders M are also possible, for example the meanders M may be oriented along an axis which is inclined at an angle with respect to an axis parallel either to the longitudinal axis XX′, or to the transverse axis YY′.

(38) In FIG. 4b, the conducting metal surface 60′ consists of the electrical ground plane 100 of the printed circuit. The ground plane is modified according to the invention and present on a part of length L at least equal to

(39) $\frac{\lambda }{6},$
meanders M, in this example, in the form of slots.

(40) The invention therefore makes it possible, in a judicious manner, through the shape of the conducting metal surface, to eliminate the disturbances in the electromagnetic radiation of the UHF antenna which are generated by the presence of said metallic surface in proximity.

(41) The invention is all the more ingenious, as the operation of the metal surface in the guise of capacitive sensor electrode or ground plane electrode is not impacted by this shape of continuous path consisting of meanders.

(42) The invention is robust, inexpensive and easy to implement and solves the problem of integrating a UHF antenna into a handle comprising metallic surfaces that disturb the operation of the UHF antenna.