FR2937451A1 - DOMOTIC DEVICE FOR TRANSMITTING AND / OR RECEIVING RADIO SIGNALS. - Google Patents

Abstract

Transmitter (10) or home automation receiver comprising an electronic circuit (18) supporting a radiofrequency unit and a planar-type primary antenna (13a) and comprising a secondary antenna (13b) galvanically isolated from the electronic circuit and magnetically coupled with the primary antenna, characterized in that a conductive ring interrupted at least once constitutes the secondary antenna, this ring also being a mechanical constituent of a housing surrounding the electronic circuit.

Description

The invention relates to a home automation transmitter or receiver for radiofrequency remote control of the actuators controlling an electrical load in a building, this electric charge being intended for thermal, visual or light comfort, solar protection, closing or the security of the building or its surroundings.

Such an emitter is of fixed type, for example in the form of a wall control point, or is nomadic type, for example in the form of a pocket remote control. Depending on the case, the transmitter is powered on the alternative sector or autonomously, for example by batteries. The transmitter can transmit orders from a user or can contain a sensor to only transmit data from this sensor, used by the actuators. The transmitter can also be a data receiver, or combine transmission and reception.

A first problem encountered with these transmitters is the permanent search for a great compactness of the electronic circuit supporting the various electronic components of the transmitter.

This results in low tolerated dimensions for the antenna of the transmitter, and thus a decrease in the antenna gain. It is therefore essential to increase the signal power to compensate for the loss of the antenna, which is done to the detriment of consumption and autonomy.

This dimensional constraint is obvious for nomadic transmitters, but it is also found in wall type transmitters, aesthetic and economic constraints compelling to reduce the dimensions of electronic circuits so that a single model can adapt to the variety. designs proposed by leading manufacturers of electrical equipment. MS \ 2. S 649.12 FR.621. A second problem encountered with wall-type transmitters is the frequent use of a hollow metal plate, which is used to rigidly fix the transmitter to the wall or to a wall box. The electronic circuit of the transmitter is generally housed in the recessed portion of the plate, just as would be housed the electromechanical elements of a rocker switch or an electrical outlet.

The metal plate then disturbs the transmission of the waves emitted by the antenna. For example, there is a transmission loss of 12 dB at 433 MHz when using a hollow steel plate forming a square frame of 1 cm average width around a square electronic circuit of 4 cm side.

Such emitters in the field of the invention are described in US Pat. No. 5,982,103. There is a physical connection between the radio circuit and the antenna. Patent applications JP 2007-141012 and JP 2007-122227 relate to the field of RFID badge readers. Multispire antennas of dimension are used such that they are included in the external frame of the reader to increase the radiation capacity of the antennas. The turns of the antennas are connected to the radio circuit by a wire link 11, with, in the last document, the possibility of switching from a first antenna to a second antenna by a switch.

The physical links between antenna and radio circuit strongly penalize the mounting conditions and the cost of the transmitters, as well as the risk of degradation during a possible dismantling.

It has been imagined in patent FR 2 724 263 to improve the impedance matching or the gain of a remote control system antenna MS \ 2. S 64 9.12 E R. 6 21. dpt for a motor vehicle by cascading a primary part and a secondary part not physically connected to the transmitter and focused on the primary part, in the manner of a parabolic reflector. This secondary part is made on a printed circuit in the form of at least one conductive track disposed on the printed circuit supporting the primary part or on a second circuit, or a label, placed above or below the latter. In one embodiment, the secondary is embedded in the body of a housing.

However, it is not always easy to integrate this antenna secondary part to the transmitter or the receiver.

The object of the invention is to provide a transmitter or a receiver remedying the problem mentioned above and improving transmitters or a known receiver of the prior art. In particular, the invention proposes a simple home automation transmitter or receiver in which an antenna secondary part integrates easily and provides an additional function to its primary function.

According to the invention, the home automation transmitter or receiver comprises an electronic circuit supporting a radiofrequency unit and a planar-type primary antenna and comprises a secondary antenna electrically isolated from the electronic circuit and magnetically coupled with the primary antenna. The home automation transmitter or receiver is characterized in that a conductive ring interrupted at least once constitutes the secondary antenna, this ring also being a mechanical component of a housing surrounding the electronic circuit.

The mechanical component can form a locking means of a first part of the housing and a second part of the housing.

MS \ 2. S649.12EN.621.dpt The locking means may comprise means for applying an elastic return force of the first housing part to the second housing part.

The mechanical component may comprise a means for stiffening at least one element of the housing. The stiffening means may be a hollowed conductive plate.

The stiffening means may be a superposition of C-shaped plates.

The holding means may comprise means for fixing the housing to a wall.

The holding means may comprise screw holes.

The appended drawing shows, by way of example, various embodiments of a home automation transmitter according to the invention.

FIG. 1 represents a home automation transmitter according to the state of the art.

Figures 2A and 2B show a first nomadic transmitter according to a first embodiment of the invention.

FIGS. 3A and 3B show a second transmitter, of nomadic type, according to a variant of the first embodiment.

Figures 4A and 4B show a third wall-type transmitter according to a second embodiment of the invention. MS \ 2. S649.12EN.621.dpt FIG. 5 shows an electrical diagram equivalent to the different embodiments.

Figure 6 details the equivalent electrical diagram in the case of the variant of the first embodiment.

Figure 7 shows electric field lines in the vicinity of an interruption of a secondary antenna. Figure 8 partially shows a first variant of the second embodiment and a related method.

Figure 9 partially shows a second variant of the second embodiment.

FIG. 1 represents a home automation transmitter 1, known from the prior art. This home automation transmitter comprises a radiofrequency unit 2 (transmitter type) connected to an antenna 3, for radiofrequency communication with an actuator or several actuators, not shown. The transmitter comprises a control unit 4, for example a microcontroller connected to the radiofrequency transmitter. The data transmitted by the control unit is converted into radio signals by the radio frequency unit for application to the antenna. A control keyboard 5 is connected to the control unit, for example on a logic input, to apply commands transmitted manually by a user. A sensor 6, for example a presence sensor or a temperature or humidity sensor, is also connected to the control unit, for example on an analog input.

MS \ 2.S649.12EN.621.dpt10 The control unit and the radiofrequency transmitter are powered by a power supply circuit 7 connected to the electrical network 7a. Alternatively, the supply circuit is autonomous and contains, for example, a dry cell or an accumulator. Alternatively, the home automation transmitter is of the receiver type and then contains a receiver type radio frequency unit. It can also be bidirectional.

FIG. 5 represents a circuit diagram equivalent to the different embodiments, by taking the references of FIG. 1. The radio frequency unit 2 (or RFU) is connected to the antenna 3 by a connection capacitor C1, also allowing frequency agreement.

According to the invention, the antenna 3 is divided between a primary antenna 3a (or Al) and a secondary antenna 3b (or A2), magnetically coupled by a KB coupling, the secondary antenna being galvanically isolated from the electronic circuit and constituting a portion of a housing surrounding an electronic circuit supporting the radio frequency unit and the primary antenna. The primary antenna is of printed planar type, formed by a winding of several concentric turns giving a first inductance LI, the capacitor C1 making it possible to adjust the resonant frequency of the resonant circuit (LI, Cl) of the primary antenna to the transmission frequency of the radio frequency unit 2.

The secondary antenna is constituted by an inductance loop L2 in series (or in parallel) with a capacitance C2 having two parallel components: a first component C21 and a second component C22 whose origin and the respective weight will be described by the following. according to

MS \ 2. In the invention, the resonant circuit of the secondary antenna is also tuned to the frequency of the radio frequency unit 2.

The important thing is that the resonant circuit thus formed has a coefficient of quality as high as possible, ie minimum ohmic losses.

In a non-optimal manner, the resonant frequency of the secondary antenna can be simply close to that of the radio frequency unit, provided that it is at least included in a bandwidth of the resonant circuit defined by an amplification coefficient higher than 1 (gain greater than 0 dB), so that this secondary antenna plays an active role and does not degrade the performance of the electronic circuit alone.

In the various embodiments, equivalent elements have even unitary reference, the ten being different from one mode to another.

FIGS. 2A and 2B show a first home automation transmitter 10, of nomadic type, according to a first embodiment of the invention. FIG. 2A represents this emitter in section and FIG. 2B is a view from above of this emitter. The section plane is perpendicular to that of the view from above and centered on the length of the transmitter.

The transmitter firstly comprises a housing made of two plastic parts, a first upper part 19a and a first lower part 19b surrounding and supporting a first electronic circuit 18. The first electronic circuit supports a first radiofrequency unit 12 and a first antenna primary 13a as a printed antenna.

In the cutting plane is a first key 15a of a control keyboard, activating a first switch 15b placed on the circuit. The

MS \ 2. 5649.12 EN.621.dpt case has a substantially parallelepipedic appearance, with connection of the faces by more or less pronounced radii of curvature leaves.

A first secondary antenna 13b is constituted by an interrupted conductive ring ensuring the closure of the housing by locking the upper part and the lower part. The conductive ring is inserted into lateral notches 19c of each plastic part, for example V-notches as shown in FIG. 2A. These notches cooperate with complementary shaped projections made on the ring 13b. The ring comprises an interruption 13c allowing its opening by deformation in order to place or deposit the upper and lower parts 19a, 19b. The interruption locally gives a capacitive character to the ring. It comprises an internal slot 13d for supporting the electronic circuit 18 on a border thereof electrically isolated. However, the support of the electronic circuit can also be provided by the lower part of the housing.

The conductive ring is sufficiently elastic to close spontaneously after being removed at the time of insertion of the plastic parts in the conductive ring. Alternatively, the ring comprises two interrupts, so made in two parts in C vis-à-vis. The locking of the housing is then not ensured by an elastic force closing the ring. However, the locking can be provided by an elastic force bringing the free ends of the wings of the C and the presence, on the wings of the C, shapes cooperating with complementary shapes on the upper and lower portions 19a, 19b.

In both cases, the ring 13b is a mechanical component of the housing. It is a means of maintaining the housing and more specifically

MS \ 2. S649.12EN.621.dpt a locking means, in particular a locking means by applying an elastic force.

FIGS. 3A and 3B show a second home-based transmitter 20, of nomadic type, according to a variant of the first embodiment of the invention. FIG. 3A represents this emitter in section and FIG. 3B is a view from above of this emitter. The trace of the cutting plane, perpendicular to the top view, appears in the form of a line XX 'in the view from above.

The transmitter also comprises a housing made of two plastic parts, a second upper part 29a and a second lower part 29b surrounding and supporting a second electronic circuit 28. The second electronic circuit supports a second radiofrequency unit 22 and a second primary antenna 23a under printed antenna form. In the cutting plane is a second key 25a of a control keyboard, activating a second switch 25b placed on the circuit. The housing has a cylindrical symmetry axis YY '.

A second secondary antenna 23b is constituted by a set of 8 conductive clips, mechanically surrounding and closing the two plastic parts of the housing and surrounding the first electronic circuit. The staples are arranged to prevent separation of the two plastic parts of the housing. For example, the clips exert on these parts an elastic force holding them against each other. The main plane of the secondary antenna is coincident or parallel with the plane of the first planar antenna, therefore with the plane of the electronic circuit. The secondary antenna thus comprises a conductive ring interrupted 8 times by 8 interruptions 23c.

MS \ 2. S649.12EN.621.dpt The secondary antenna is thus constituted by a discontinuous conducting ring and thus has an elementary inductance and an elementary capacitance for each clip and / or for the coupling between adjacent staples. There is therefore an 8-part distribution of the inductance and the capacitance along the secondary antenna.

In an equivalent diagram of the type of FIG. 5, the secondary antenna 23b comprises 8 identical elementary LC cells. FIG. 6 details the electrical diagram equivalent to such a secondary antenna by placing in series of elementary LC cells, each cell being characterized by an elementary inductor dL2 and by an elementary capacitance dC2. Elementary abilities come from discontinuities in a conducting ring regularly cut by radial planes perpendicular to the main plane of the ring. The elementary inductance is then the total inductance of the ring divided by the number of volumes divided. The antenna volume is then that of the ring before cutting.

A regular character of the sections gives equality for the values of each elementary capacitance or elementary inductance, but is not essential for the proper functioning of the invention.

The magnetic coupling KB between the primary antenna and the secondary antenna is represented by a dashed double-arrow. The housing comprises the two plastic parts and the set of staples forming secondary antenna.

Alternatively, this variant of the first embodiment can use two staples only, with each staple occupying almost all of a semicircle or any other number of staples. MS \ 2. S649.12EN.621.dpt In both cases, the staples 23b are a mechanical component of the housing. They constitute a housing holding means and more specifically a locking means, in particular a locking means by applying an elastic force.

FIG. 4A is a top view and FIG. 4B is a sectional view of a third home automation transmitter 30, of wall type, according to a third embodiment of the invention. In Fig. 4A, the frame and cover housing parts of the transmitter are shown in transparency for clarity.

The transmitter comprises a frame 39a, rectangular, surrounding and supporting a third electronic circuit 38 with unreferenced slides. The third electronic circuit 38 supports a third radio frequency unit 32 and a third primary antenna 33a in the form of a printed planar antenna.

The third electronic circuit also supports a third switch 35b.

The section plane of FIG. 4B is perpendicular to the main plane of the secondary antenna and passes on a section line AA '. A cover 39b is shown in raised position. A third key 35a is shown in the section plane, at the right of the switch 35b.

A third secondary antenna 33b consists of a hollowed conductive metal plate integrated in the frame 39a. The main plane of the secondary antenna is coincident or parallel with the plane of the planar antenna 30, so with the plane of the electronic circuit. The metal plate comprises a disconnection interrupt 33c MS \ 2.S649.12FR.621.dpt of sectioning thickness D3, forming a sectioning capacitance.

The magnetic coupling KB between the primary antenna and the secondary antenna is represented by two double arrows in dashed line.

The secondary antenna 33b is a mechanical component of a housing constituted for example by the third frame comprising the secondary antenna, the third cover and a wall. It allows in particular the attachment of the transmitter to a wall 100, for example by means of screws through screw holes therethrough. Thus, it is a means of maintaining the housing. In particular, it comprises means for fixing the housing constituted by the screw holes. Alternatively or additionally, the hollowed conductive metal plate integrated into the frame constitutes a means for holding the housing in the sense that it allows it to be maintained in its initial shape under the effect of mechanical stresses. In other words, the plate constitutes a rigidifcation means of the frame and thus of the housing.

Due to the plating of the metal plate against the wall, the antenna / wall capacitance plays an important role in the resonance of the resonant circuit constituted by the secondary antenna. In the equivalent diagram of Figure 5, the sectioning capacitance is designated C21, while the antenna / wall capacitance is designated C22.

FIG. 7 represents electric field lines in the vicinity of an interruption of a secondary antenna x3b, seen in section. The sectioning x3c has a sectioning width Dx. The electric field has a greater intensity in the sectioning, but it has a thickness limited to that of the conductive plate: the surfaces directly opposite are therefore weak. The fields

MS \ 2. S649.12EN.621.dpt, closing on surfaces in prolongation and not vis-à-vis, are lower but correspond to much larger surfaces. It is thus shown that the sectioning capacitance integrates not only the geometrical parameters of the two conductive sections opposite in the sectioning but also the conductive zones in the vicinity of the sectioning.

Figure 8 partially shows a first variant of the second embodiment and a related method. As in a single-phase transformer, at least two C-shaped conductive sheets are used which are electrically isolated from one another and pressed against each other.

A first sheet C, referenced 13b1, is identical to a second sheet C, referenced 13b2. One sheet is turned relative to the other and superimposed, as indicated by a solid arrow, so as to form a closed frame. Fastening holes 13j and 13k of the first sheet thus correspond to fastening holes 13k and 13j of the second sheet. Thus, the two sheets are pressed against each other during screwing through the fixing holes. The screwing can be done directly in the wall or on a part of the support.

According to the greater or lesser value of capacity sought, the galvanic isolation between sheets is achieved by surface oxidation or by insertion of Mylar sheet or other insulating plastic to give a greater or lesser thickness to the interruption. This embodiment gives the advantage of a very high rigidity.

Figure 9 partially shows a second variant of the second embodiment. The sectioning 13d comprises a strong longitudinal component, dividing the secondary antenna 13b in two

MS \ 2. S649.12EN.621.dpt longitudinal sections 13e and 13f in the sectioning area. These longitudinal parts provide greater rigidity of the housing if they cooperate with antagonistic forms of the frame 39a.

The secondary antenna may consist of several conducting rings each interrupted. MS \ 2. S649.12FR.621.dpt

Claims (8)

1. Transmitter (10, 20, 30) or home automation receiver comprising an electronic circuit (18, 28, 38) supporting a radio frequency unit and a planar-type primary antenna (13a, 23a, 33a) and comprising a secondary antenna ( 13b, 23b, 33b) electrically isolated from the electronic circuit and magnetically coupled with the primary antenna, characterized in that a conductive ring interrupted at least once constitutes the secondary antenna, this ring also being a mechanical component of a housing surrounding the electronic circuit. 2. Emitter or home automation receiver according to claim 1, characterized in that the mechanical component forms a locking means of a first portion (19a, 29a) of the housing and a second portion (19b, 29b) of the housing. 3. Transmitter or home automation receiver according to claim 2, characterized in that the locking means comprises means for applying an elastic return force of the first housing part on the second housing part. 4. Transmitter or home automation receiver according to claim 1, characterized in that the mechanical component comprises a means for stiffening at least one element (39a) of the housing. 5. Emitter or home automation receiver according to claim 4, characterized in that the stiffening means is a hollowed conductive plate. MS \ 2.S649.12EN.621.dpt 30 6. Emitter or home automation receiver according to claim 4, characterized in that the stiffening means is a superposition of C-shaped plates. 7. Emitter or home automation receiver according to one of claims 1, 4, 5 or 6, characterized in that the holding means comprises means for fixing the housing on a wall. 8. Transmitter or home automation receiver according to claim 7, characterized in that the holding means comprises screw holes. MS \ 2. S649.12FR.621.dpt