WO2017174891A1

WO2017174891A1 - Control device for a vehicle and method for producing a control device

Info

Publication number: WO2017174891A1
Application number: PCT/FR2017/050665
Authority: WO
Inventors: Omar Ben Abdelaziz
Original assignee: Faurecia Interieur Industrie
Priority date: 2016-04-07
Filing date: 2017-03-21
Publication date: 2017-10-12
Also published as: FR3049914B1; DE112017001872T5; FR3049914A1

Abstract

Control device (1), in particular for a vehicle, comprising a main printed circuit board (10), a secondary element with printed circuit (20) arranged on the main printed circuit board (10) and a piezoelectric sensor (30). The main printed circuit board (10) comprises a first main upper track (14a) and a second main upper track (14b). The secondary element with printed circuit (20) comprises a first secondary lower track (22a). The piezoelectric sensor (30) comprises a first electrode (32) and a second electrode (34). The second electrode (34) of the piezoelectric sensor (30) is electrically connected to the first secondary lower track (22a). The first electrode (32) of the piezoelectric sensor (30) is electrically connected to the second main upper track (14b).

Description

Vehicle control device and method for making a control device

Field of the invention

The invention relates to a control device, in particular for a vehicle, and a method for producing such a control device.

Context of the invention

Such a control device is sometimes referred to as a control button. The invention more particularly relates to a control device comprising at least one piezoelectric sensor, in particular for the detection of tactile commands.

Such a device is generally disposed in the passenger compartment of the vehicle, in particular, on a dashboard, a central console, a door panel or a ceiling lamp. It makes it possible to control the activation or the deactivation of devices equipping the vehicle.

The invention aims in particular to provide a control device providing reliable operation in a wide range of temperatures and can be easily achieved, particularly in an automated manner.

Presentation of the invention

According to the invention, the control device comprises: a printed circuit main board comprising:

An electrically insulating main layer,

An upper main layer comprising at least a first upper and a second upper main track, electrically conductive,

a printed circuit secondary element comprising:

A secondary support, electrically insulating,

A lower secondary layer comprising at least a first electrically conductive lower secondary track,

a piezoelectric sensor comprising a first electrode and a second electrode. In addition, according to the invention, the control device has the following characteristics:

the printed circuit secondary element is disposed on the main circuit board,

the second electrode of the piezoelectric sensor is electrically connected to the first lower secondary track,

the first lower secondary track is electrically connected to the first upper main track, and

the first electrode of the piezoelectric sensor is electrically connected to the second upper main track.

A printed circuit board usually has good flatness. Therefore, by arranging the secondary circuit element on the printed circuit board, it is possible to electrically connect the elements carried by the main circuit board and the elements carried by the printed circuit secondary element. Thus, it is necessary to use a single connector connected to the main printed circuit board so that the entire control device is connected to the electrical circuit of the vehicle. In addition, the stiffness of the control device is increased, which reduces the effort required to detect pressure and improves haptic feedback.

The terms "upper" and "lower" allow the elements to be positioned relative to each other in a usual position where the surface on which the user must press to act on the control device is located at the top. However, these terms do not limit the scope of the claimed protection, the control device being able to be arranged in any position.

According to the invention, the control device preferably also has the following characteristics:

the lower secondary layer further comprises at least a second, electrically conductive lower secondary track,

the printed circuit secondary element further comprises an upper secondary layer comprising at least one upper electrically conductive secondary track, the secondary support is arranged between the lower secondary layer and the upper secondary layer, and

the second electrode of the piezoelectric sensor is electrically connected to the first lower secondary track via the upper secondary track, the upper secondary track being electrically connected on the one hand to the first lower secondary track and on the other hand to the second electrode of the piezoelectric sensor via the second lower secondary track.

The embodiment of the printed circuit secondary element is thus simplified and made more reliable.

According to another feature of the invention, preferably the piezoelectric sensor comprises a metal disk, the metal disk is connected to the first electrode and has a lower face and an upper face, and the lower face of the metal disk is in contact with the main circuit board and the upper face of the metal disk are in contact with the printed circuit secondary element.

Thus, the piezoelectric sensor is maintained between the main circuit board and the secondary circuit element.

According to a complementary characteristic according to the invention, preferably the lower secondary layer further comprises an intermediate track electrically connected to the upper face of the metal disc, independently of the main circuit board, and the intermediate track is electrically connected to the second upper main track, independent of the piezoelectric sensor.

Thus, the control device is simple and the electrical connection of the piezoelectric sensor with the main circuit board is improved.

According to an alternative or complementary characteristic according to the invention, preferably the lower face of the metal disk is electrically connected to the second upper main track independently of the secondary circuit element, the lower face of the metal disk being in contact with the upper main layer. The electrical connection of the piezoelectric sensor with the main circuit board is thus improved without complicating the control device.

According to another characteristic according to the invention, preferably the control device further comprises:

an opaque decor layer having an opening forming a pictogram opposite the piezoelectric sensor,

- a source of light, and

- A light guide, disposed between the decorative layer and the secondary circuit element, and adapted to transmit light from the light source to the opening in the decorative layer.

Thus, the control device is backlit. The backlight makes it possible to locate the location of the control device in the dark and / or to inform a user of the state of the device that the control device makes it possible to control.

According to a complementary characteristic according to the invention, preferably the light source is carried by the main board and connected to the upper main layer, and the light source comprises a block extending through a passage in the secondary element. printed circuit board.

Thus, the realization of the control device is simplified.

Preferably, according to the invention, the control device further comprises the following characteristics:

the piezoelectric sensor constitutes a first piezoelectric sensor,

the control device further comprises a second piezoelectric sensor comprising a first electrode and a second electrode,

the second electrode of the second piezoelectric sensor is electrically connected to the first lower secondary track,

the upper main layer comprises a third upper main track, and

the first electrode of the second piezoelectric sensor is electrically connected to the third upper main track. Thus, a plurality of control areas are easily realized in the control device.

In various embodiments of the device according to the invention, one or more of the following provisions may also be used:

the piezoelectric sensor is disposed between the main circuit board and the printed circuit secondary element;

- The control device further comprises a support, the support has an upper face extending opposite the main circuit board;

the control device further comprises a lower main layer and electrical components, the lower main layer comprising at least one lower electrically conductive main track, the main support layer is arranged between the lower main layer and the upper main layer, and the electrical components are electrically connected to the lower main layer;

- The secondary circuit element is flexible, the secondary support being constituted by a plastic film.

The invention further relates to a method. According to the invention, the method comprises the following steps:

a printed circuit main board is provided comprising:

An electrically insulating main layer,

a printed circuit secondary element is provided, comprising:

A secondary support, electrically insulating,

A lower secondary layer comprising at least a first electrically conductive lower secondary track; a piezoelectric sensor comprising a first electrode and a second electrode is provided, the piezoelectric sensor is held on the secondary element and the second electrode of the piezoelectric sensor is electrically connected to the first lower secondary track, and then

the printed circuit secondary element is arranged on the printed circuit main board, the first lower secondary track is electrically connected to the first upper main track, and the first electrode of the piezoelectric sensor is electrically connected to the second upper main track.

Brief description of the figures

Other features and advantages of the present invention will become apparent from the following detailed description, with reference to the accompanying drawings in which:

FIG. 1 illustrates a control device according to the invention,

FIG. 2 illustrates the section control device along the line II-II indicated in FIG.

FIG. 3 illustrates the production of a first subassembly according to a method according to the invention for producing the control device,

FIG. 4A illustrates a first step of producing a second subassembly,

FIG. 4B illustrates a second step of producing the second subassembly,

FIG. 4C illustrates a third step of producing the second subset,

FIG. 5A illustrates a first step of producing a third subassembly,

FIG. 5B illustrates a second step of producing the third subassembly,

FIG. 5C illustrates a third step of producing the third subassembly,

FIG. 5D illustrates a fourth step of making the third subset, FIG. 5E illustrates a fifth stage of realization of the third subassembly,

FIG. 6A illustrates a first step of making a fourth first subset,

FIG. 6B illustrates a second step of producing the fourth subset.

Detailed description of the invention

Figures 1 and 2 illustrate a trim element 1 10 disposed in a vehicle cabin 100. In the illustrated embodiment, the trim element 1 10 is a dashboard and more precisely a center console dashboard.

The covering element 1 10 comprises a control device 1. The control device 1 illustrated has three control zones 2, 4, 6. The control device is controllable by pressure on a control surface 42a visible from the passenger compartment 100. In each control zone 2, 4, 6, the control surface 42a has a pictogram 44. The shape of the pictogram is specific to each control zone 2, 4, 6.

The control device 1 comprises in particular a support 50, a main board subassembly 19, a sub-unit subassembly 29 and a decoration subassembly 49.

The main board subassembly 19 essentially comprises a main printed circuit board 10. The main printed circuit board 10 comprises an optional lower main layer 12, an upper main layer 14 and a main support layer 16. The main support layer 16 is arranged between the lower main layer 12 and the upper main layer 14. Optionally, the lower main layer 12 and possibly the upper main layer 14 may be covered with a protective layer of electrically insulating varnish. Inside the main circuit board 10, the main support layer 16 forms a support, in particular for the lower main layer 12 and the upper main layer 14. The main circuit board 10, and in particular the main support layer 16, is rigid, so that it does not deform under its own weight.

The lower main layer 12 is made of electrically conductive material, such as copper. The lower main layer 12 is cut into different lower main tracks 12a and electronic components 1 1 fixed under the main circuit board 10 are connected to these different tracks.

The upper main layer 14 is also made of electrically conductive material, such as copper. The upper main layer 14 comprises in particular a first upper main track 14a, a second upper main track 14b, a third upper main track 14c and a fourth upper main track 14d. Notches 17 in the upper main layer 14 electrically isolate the first upper main track 14a, second upper main track 14b, third upper main track 14c and the fourth upper main track 14d from each other.

For each control zone 2, 4, 6, a light source 60 formed by a light-emitting diode carried by a pad 62 is supported by the printed circuit board 10. The light sources 60 of the control zones 2, 4, 6, preferably light-emitting diodes 60, are respectively connected to a first main light track 14e, a second main light track 14f and a third main light track 14g. The first main lighting track 14e, second main lighting track 14f and third main lighting track 14g are electrically isolated from each other and with respect to the first upper main track 14a, the second upper main track 14b, the third upper main track 14c and fourth upper main track 14d by the notches 17.

The main board subassembly 19 further comprises an electrical connector 13 by control zone 2, 4, 6, these electrical connectors 13 being electrically connected respectively to the second upper main track 14b, the third upper main track 14c and fourth upper main track 14d. In addition, an electrical connector 13 is electrically connected to the first upper main track 14a. The electrical connectors 13 are advantageously soldered on the main circuit board 10.

The main circuit board 10 comprises a circular section cutout in each of the control areas 2, 4, 6.

In addition, the main circuit board 10 includes a passage 18 therethrough in each of the control areas 2, 4, 6.

The sub-unit subassembly 29 essentially comprises a printed circuit secondary element 20 and piezoelectric sensors 30. The printed circuit secondary element 20 comprises a lower secondary layer 22, an optional upper secondary layer 24 and a secondary support 26 The secondary support 26 is arranged between the lower secondary layer 22 and the upper secondary layer 24. Optionally, the upper secondary layer 24 and possibly the lower secondary layer 22 may be covered with a protective layer of electrically insulating varnish. Inside the main circuit board 10, the secondary support 26 forms a support in particular for the lower secondary layer 22 and the upper secondary layer 24. The secondary circuit element 20, and in particular the secondary support 26, is flexible, so that it deforms under its own weight. Preferably, the secondary support 26 is formed by a film of less than one millimeter thick, a few tenths of a millimeter, preferably polycarbonate (PC) or polyethylene terephthalate (PET).

The lower secondary layer 22 is made of electrically conductive material, such as copper. The lower secondary layer 22 comprises in particular a first lower secondary track 22a, a second lower secondary track 22b, a third lower secondary track 22c and a fourth lower secondary track 22d. Notches 27 in the lower secondary layer 22 can electrically isolate the first lower secondary track 22a, second lower secondary track 22b, third lower secondary track 22c and fourth lower secondary track 22d from each other.

The lower secondary layer 22 further comprises a first lower intermediate track 22e, a second lower intermediate track 22f and a third lower intermediate track 22g.

The secondary circuit element 20 further comprises an annular cut-out 25 around the second lower secondary track 22b, the third lower secondary track 22c and the fourth lower secondary track 22d in each of the control zones 2, 4, 6. lower intermediate track 22e, second lower intermediate track 22f and third lower intermediate track 22g are electrically insulated from the first lower secondary track 22a, second lower secondary track 22b, third lower secondary track 22c and the fourth lower secondary track 22d, in particular by the cuts 25.

The upper secondary layer 24 is also made of electrically conductive material, such as copper. The upper secondary layer 24 comprises an upper secondary track 24a.

The secondary circuit element 20 further comprises a first via 21a, a second via 21b, a third via 21c and a fourth via 21d. The first via 21a electrically connects the upper secondary track 24a to the first lower secondary track 22a through the secondary support 26. The second via 21b electrically connects the upper secondary track 24a to the second lower secondary track 22b by going to through the secondary support 26. The third via 21c electrically connects the upper secondary track 24a to the third lower secondary track 22c through the secondary support 26. The fourth via 21 d electrically connects the upper secondary track 24a to the fourth track lower secondary 22d passing through the secondary support 26.

The secondary subassembly 29 comprises a piezoelectric element sensor 30 per control zone 2, 4, 6. In each control zone 2, 4, 6, the piezoelectric sensor 30 comprises a disk-shaped ceramic element 36 and a metallic element 38 in the form of disk. The ceramic element 36 has a lower face forming a first electrode 32 and an upper face forming a second electrode 34. The metal element 38 has a lower face 38a and an upper face 38b. The ceramic element 36 and the metal element 38 are superposed, the upper face 38b of the metal element 38 being in contact with the lower face of the ceramic element 36.

The first electrode 32 is thus electrically connected to the metal element 38. The upper face of the ceramic element 36 is fixed to the lower secondary layer 22 in an electrically conductive manner, preferably by means of an electrically conductive adhesive. especially with silver. Thus, in the control zones 2, 4, 6, the second electrode 34 of the piezoelectric sensor 30 is electrically conductive respectively fixed to the second lower secondary track 22b, the third lower secondary track 22c and the fourth lower secondary track 22d.

In each control zone 2, 4, 6, the metal element 38 of the piezoelectric sensor 30 is electrically connected to the first electrode 32. In addition, in each control zone 2, 4, 6, the metal element 38 is maintained between the upper main layer 14 and the lower secondary layer 22.

Thus, the lower face 38a of the metal element 38 is in contact with the upper main layer 14. In particular, in the control zones 2, 4, 6, the lower face 38a of the metal element 38 is directly electrically connected. respectively to the second upper main track 14b, the third upper main track 14c and the fourth upper main track 14d.

And, the upper face 38b of the metal element 38 is in contact with the lower secondary layer 22. In particular, in the control zones 2, 4, 6, the upper face 38b of the metal element 38 is electrically connected respectively at the first lower intermediate track 22e, the second lower secondary intermediate track 22f and the third lower intermediate track 22g. An electrically conductive adhesive, in particular based on silver, is advantageously arranged between the upper face 38b of the metal element 38 and the lower secondary layer 22.

The electrical connectors 13 electrically connect the upper main layer 14 and the lower secondary layer 22. In particular, the electrical connectors 13 electrically connect respectively the first upper main track 14a and the first lower secondary track 22a, the second upper main track 14b and the first lower intermediate track 22e, the third upper main track 14c and the second lower intermediate track 22f, the fourth upper main track 14d and the third lower lower track 22g. The electrical connectors 13 advantageously comprise an elastic element making it possible to ensure permanent electrical contact between the tracks of the main circuit board 10 and the tracks of the printed circuit secondary element 20. The electrical connector is for example a contact at spring.

In addition, the printed circuit secondary element 20 comprises a passage 28 passing through it in each of the control zones 2, 4, 6.

Subassembly subassembly 29 further includes a lower adhesive sheet 56, preferably of the double-sided adhesive type. The lower adhesive sheet 56 is opposite the lower secondary layer 22 and the upper main layer 14. It maintains the printed circuit secondary element 20 with respect to the main printed circuit board 10.

The sub-unit subassembly 29 also includes an upper adhesive sheet 58, preferably of the double-sided adhesive type. The upper adhesive sheet 58 is opposite the upper secondary layer 24 and the decor subassembly 49. It maintains the decoration subassembly 49 with respect to the printed circuit secondary element 20.

The decorating subassembly 49 comprises a decorative layer 42 and a translucent material light guide layer 46. The decorative layer 42 comprises the control surface 42a and has openings forming the pictograms 44. The decorative layer 42 is opaque. It is advantageously made of plastic, glass, wood or metal such as aluminum and carbon fibers. The light guide 46 is preferably made of polycarbonate (PC) or polyethylene terephthalate (PET).

Between each control zone 2, 4, 6, the light guide 46 has recesses 48. At the recesses 48, the light guide 46 has a thickness reduction of more than half of its nominal thickness. Thus, at the level of the recesses 48, the light guide has a thickness of less than 0.5 millimeters, preferably of the order of 0.3 millimeters, while its nominal thickness is advantageously slightly greater than 1 millimeter, from order of 1, 2 millimeters. Alternatively, the light guide 46 could comprise distinct portions for each control zone 2, 4, 6.

The support 50 is made of rigid and opaque plastic material. It has a lower face 50a and an upper face 50b and comprises separating partitions 52 projecting from the upper surface 50b. The separating partitions 52 pass through the passages 18 of the main printed circuit board 10, the passages 28 of the printed circuit secondary element 20 and fit into the recesses 48 of the light guide 46, between the control zones 2, 4, 6. Thus, the partition walls 52 prevent the passage of light from a control zone 2, 4, 6 to an adjacent control zone.

A method for making the controller will now be described.

FIG. 3 illustrates the embodiment by molding of the support 50 integrating the separating partitions 52.

FIGS. 4A to 4C illustrate the making of the main board subassembly 19. As shown in FIG. 4A, a flat printed circuit board comprising a lower main layer 12, a main support layer 16 and a upper main layer 14 and uniform thickness. As illustrated in FIG. 4B, the cuts 15, the cuts 17 and the passages 18 are then made. Then, as illustrated in FIG. 4C, the electrical connectors 13, the light sources 60 are connected to the upper main layer 14 and the electronic components 1 1 to the lower main layer 12.

FIGS. 5A to 5C illustrate the embodiment of secondary subassembly 29. As shown in FIG. 5A, there is provided a printed circuit secondary element 20 comprising a lower sub-layer 22, a secondary support 26 and a diaper upper secondary 24 and uniform thickness. As illustrated in FIG. 5B, the cuts 25, the cuts 27, the passages 28 and the vias 21a, 21b, 21c, 21d are then made. The notches 27 generate the creation of the first lower secondary track 22a, the second lower secondary track 22b, the third lower secondary track 22c, the fourth lower secondary track 22d, the first lower intermediate track 22e, the second lower intermediate track 22f and the third lower intermediate track 22g. As illustrated in FIG. 5C, the upper layer 24 being arranged at the bottom and the lower layer 22 being disposed at the top, the glue 35 is then deposited on the second lower secondary track 22b, the third lower secondary track 22c and the fourth track. lower secondary 22d. Advantageously, glue is also deposited on the lower intermediate track 22e, the second lower intermediate track 22f and the third lower intermediate track 22g. Alternatively, the adhesive 35 could be placed on the piezoelectric sensors 30 on the upper face of the ceramic element 36 and / or on the upper face 38b of the metal element 38.

As illustrated in FIG. 5D, in each control zone 2, 4, 6, the piezoelectric sensors 30 are arranged on the printed circuit secondary element 20, with the first electrode 32 in contact with the first lower intermediate track respectively. 22e, the second lower intermediate track 22f and the third lower intermediate track 22g, and the second electrode 34 electrically connected respectively to the second lower secondary track 22b, the third lower secondary track 22c and the fourth lower secondary track 22d via glue 35. Then, as shown in Figure 5E, applies the lower adhesive sheet 56 on the lower secondary layer 22 and the upper adhesive sheet 58 on the upper secondary layer 24.

FIGS. 6A and 6B illustrate the embodiment of the decoration subassembly 49. As illustrated in FIG. 6A, the decorative layer 42 having the openings 44 is provided. Then, the light guide 46 comprising the recesses 48 on the decorative layer 42, the light guide 46 filling the openings 44 of the decorative layer 42, as shown in Figure 6B.

In addition, the main board subassembly 19 is disposed on the support 50 by passing the separating partitions 52 through the passages 18, to bring the lower main layer 12 facing the upper face 50b of the support 50. Then, the sub-unit subassembly 29 is disposed on the main printed circuit board 10 by passing the separating partitions 52 through the passageways 28 and adhering the lower adhesive sheet 56 to the upper main layer 14. Finally, the decorator subassembly 49 is disposed on the printed circuit secondary member 20 by inserting the end of the separating partitions 52 into the recesses 48 and adhering the upper adhesive sheet 58 to the light guide 46.

The cut-outs 15 in the main printed circuit board 10 allow the piezoelectric sensors 30 to form and be controlled for haptic feedback without the risk of the piezoelectric sensors 30 coming into contact with the main printed circuit board 10.

Naturally, the invention is not limited to the embodiment (s) described for illustrative, non-limiting. Thus, instead of making through-cuts through the main circuit board 10, it could be provided to superficially dig the main printed circuit board 10.

Furthermore, instead of connecting the second lower secondary track 22b, the third lower secondary track 22c and the fourth lower secondary track 22d to the first lower secondary track 22a via the upper secondary track 24a, it would be possible to connect directly the second lower secondary track 22b, the third track lower secondary 22c and the fourth lower secondary track 22d directly (direction through the upper secondary track 24a) to the first lower secondary track 22a, so that the first lower secondary track 22a, the second lower secondary track 22b, the third secondary track lower 22c and the fourth lower secondary track 22d form the same track in the lower secondary layer 22.

In addition, for each control zone 2, 4, 6, the second upper main track 14b, the third upper main track 14c or the fourth upper main track 14d could be connected to the first electrode 32 of the piezoelectric sensor 30 only by intermediate respectively the first lower intermediate track 22e, the second lower intermediate track 22f and the third lower intermediate track 22f.

Conversely, the first lower intermediate track 22e, the second lower intermediate track 22f or the third lower secondary track 22f could be omitted, so that the second upper main track 14b, the third upper main track 14c or the fourth upper main track 14d would be connected to the first electrode 32 of the piezoelectric sensor 30 without passing through the secondary circuit element 20.

Finally, the secondary circuit element could be constituted by a rigid printed circuit board.

Claims

1. Control device (1), in particular for a vehicle, comprising:

a main circuit board (10) comprising:

· An electrically insulating main support layer (16),

An upper main layer (14) comprising at least a first electrically conductive upper main track (14a) and a second upper main track (14b),

a printed circuit secondary element (20) comprising:

"A secondary support (26), electrically insulating,

A lower secondary layer (22) comprising at least a first electrically conductive lower secondary track (22a),

a piezoelectric sensor (30) comprising a first electrode (32) and a second electrode (34),

in which :

the printed circuit secondary element (20) is arranged on the main circuit board (10),

the second electrode (34) of the piezoelectric sensor (30) is electrically connected to the first lower secondary track (22a),

the first lower secondary track (22a) is electrically connected to the first upper main track (14a), and

the first electrode (32) of the piezoelectric sensor (30) is electrically connected to the second upper main track (14b).

2. Control device according to claim 1 wherein:

the lower secondary layer (22) further comprises at least a second electrically conductive lower secondary track (22b),

the printed circuit secondary element (20) further comprises an upper secondary layer (24) comprising at least one electrically conductive upper secondary track (24a), the secondary support (26) is arranged between the lower secondary layer (22) and the upper secondary layer (24),

the second electrode (34) of the piezoelectric sensor (30) is electrically connected to the first lower secondary track (22a) via the upper secondary track (24a), the upper secondary track (24a) being electrically connected to a part to the first lower secondary track (22a) and secondly to the second electrode (34) of the piezoelectric sensor (30) via the second lower secondary track (22b).

3. Control device according to claim 1 or claim

2 in which:

the piezoelectric sensor (30) comprises a metal disc, the metal disc (38) is connected to the first electrode (32) and has a lower face (38a) and an upper face (38b), and

the lower face (38a) of the metal disk (38) is in contact with the main circuit board (10) and the upper face (38b) of the metal disk (38) is in contact with the secondary circuit element (20).

4. Control device according to the preceding claim wherein:

the lower secondary layer (22) further comprises an intermediate track (22e) electrically connected to the upper face (38b) of the metal disc (38), independently of the main circuit board (10), and

the intermediate track (22e) is electrically connected to the second upper main track (14b), independently of the piezoelectric sensor

(30).

A control device according to claim 3 or claim 4 wherein the lower face (38a) of the metal disk (38) is electrically connected to the second upper main track (14b) independently of the secondary circuit element (20). ), the lower face (38a) of the metal disc (38) being in contact with the upper main layer (14).

6. Control device according to any preceding claim further comprising:

an opaque decorative layer (42) having an opening (44) forming a pictogram opposite the piezoelectric sensor,

a light source (60),

a light guide (46) disposed between the decorative layer (42) and the printed circuit secondary element (20) and capable of transmitting light from the light source (60) to the opening ( 44) in the decorative layer (42).

7. Control device according to the preceding claim wherein the light source (60) is carried by the main board (10) and connected to the upper main layer (14), and the light source (60) comprises a stud ( 62) extending through a passage (28) in the printed circuit secondary element (20).

8. Control device according to any one of the preceding claims wherein:

the piezoelectric sensor constitutes a first piezoelectric sensor (30),

the control device further comprises a second piezoelectric sensor (30) comprising a first electrode (32) and a second electrode (34),

the second electrode (34) of the second piezoelectric sensor (30) is electrically connected to the first lower secondary track (22a),

the upper main layer (14) comprises a third upper main track (14c), and

the first electrode (32) of the second piezoelectric sensor (30) is electrically connected to the third upper main track (14c).

9. Control device according to any one of the preceding claims further comprising a support (50), the support (50) has an upper face (50b) extending opposite the main circuit board (10).

10. Control device according to any preceding claim further comprising:

a lower main layer (12) comprising at least one electrically conductive lower main track (12a), the main support layer (16) being arranged between the lower main layer (12) and the upper main layer (14), and

- Electrical components (1 1) electrically connected to the lower main layer (12).

1 1. Control device according to any of the preceding claims wherein the printed circuit secondary element (20) is flexible, the secondary support (26) being constituted by a plastic film.

12. A method for producing a control device in which the following steps are carried out:

a printed circuit main board (10) is provided comprising:

· An electrically insulating main support layer (16),

a printed circuit secondary element (20) is provided, comprising:

A secondary support (26), electrically insulating,

a piezoelectric sensor (30) is provided comprising a first electrode (32) and a second electrode (34),

the piezoelectric sensor (30) is held on the secondary element (20) and the second electrode (34) of the piezoelectric sensor (30) is electrically connected to the first lower secondary track (22a), and

the printed circuit secondary element (20) is arranged on the main circuit board (10), the first lower secondary track (22a) is electrically connected to the first upper main track (14a), and the first electrode (32) of the piezoelectric sensor (30) is electrically connected to the second upper main track (14b).