Filling element comprising a functional layer of carbon material

Abstract

Packing element comprising a functional layer of carbon material. The packing element (1) comprises at least one support layer (2), comprising an inner face (8) and an outer face (10), and at least one functional layer (6) of carbon material extending over at least a portion of the inner face (8) and / or at least a portion of the outer face (10) of the support layer (2). A portion of said functional layer (6) defines a pattern (18) comprising at least one conductive zone (20) of carbon material and at least one non-conductive zone (22) formed by a through-hole in the functional layer (6), said conductive zone (20) being supplied by a current source electrically connected to the conductive zone (20), the pattern (18) forming at least part of an electrical circuit arranged to perform a function. Figure for the abbreviation: 1

Description

Title of the invention: Filling element comprising a functional layer of carbon material

[0001] The present invention relates to a packing element of the type comprising at least one support layer, comprising an internal face and an external face, and at least one functional layer of carbon material extending over at least part of the internal face and / or over at least part of the external face of the support layer.

[0002] The invention also relates to a method for producing such a packing element.

[0003] The invention applies for example to a trim element forming a door panel, a central console or dashboard covering of a vehicle or other.

[0004] In such a trim element, it is desirable to integrate certain functionalities intended for the occupants of the vehicle on the external surface of the trim element. Thus, the trim element may for example comprise touch surfaces to enable certain functions of the vehicle to be controlled, detection surfaces to detect contact with the external surface or other.

[0005] The functional elements for performing these functions, such as printed circuits, are integrated into the trim element, for example under a decorative layer so as not to be visible from the passenger compartment of the vehicle. To do this, the circuits are for example glued to the support layer before the decorative layer is applied to the support layer. Such a method is however tedious and can be complicated, in particular when several functional surfaces are provided, various functional elements then having to be fixed at various locations on the support layer.Furthermore, in the event of poor positioning of the functional element(s) on the support layer and / or in relation to the decorative layer, the quality of the filling element is degraded because the functional surfaces do not extend exactly opposite the indications provided on the external surface of the filling element to indicate their presence and / or their activation zone.

[0006] One of the aims of the invention is to overcome these drawbacks by proposing a trim element comprising one or more functional surfaces which can be produced in a simple and reliable manner.

[0007] To this end, the invention relates to a packing element of the aforementioned type, in which at least a part of said functional layer defines at least one pattern comprising at least one conductive zone made of carbon material and at least a non-conductive area formed by a through opening in the functional layer, said conductive area being powered by a current source electrically connected to the conductive area, the pattern forming at least part of an electrical circuit arranged to perform an interaction function with a passenger of the vehicle on an external surface of the trim element.

[0008] By producing the pattern in a functional layer made of carbon material, a functional electrical circuit can be defined at a precise location on the support layer in a simple and reliable manner. Furthermore, when several functional electrical circuits are provided, they can all be produced in the functional layer(s), which limits the operations for producing the filling element and simplifies the relative positioning of the different functional electrical circuits on the support layer.

[0009] According to other characteristics of the packing element according to the invention, taken in isolation or in any technically conceivable combination:

[0010] - the trim element comprises a decorative layer extending opposite the outer face of the support layer and forming the outer surface of the filling element;

[0011] - the external surface of the packing element is formed by the support layer and / or by the functional layer;

[0012] - the packing element comprises an outer functional layer extending on at least a portion of the outer face of the support layer and an inner functional layer extending over at least a portion of the inner face of the support layer, the patterns of the outer and inner functional layers forming a capacitive circuit so as to form a touch surface on at least a portion of the outer surface of the trim element;

[0013] - the pattern of the functional layer forms a flexible resistive circuit so as to form a pressure sensor on at least a portion of the outer surface of the packing element;

[0014] - the filling element comprises an outer functional layer and a layer internal functional layer, the external functional layer being separated from the internal functional layer by the support layer or by a flexible layer, the patterns of the external functional layer and the internal functional layer forming a capacitive circuit whose capacitance varies according to the distance separating the external functional layer from the internal functional layer, said distance varying by reversible crushing of the support layer or the flexible layer when pressure is exerted on the external surface of the filling element;

[0015] - the support layer is made of a composite material comprising fibers natural in a polypropylene matrix;

[0016] - the pattern is formed in a functional layer extending on the external face of the support layer, said pattern forming a functional part of an electrical circuit, said electrical circuit comprising a power supply part extending on the inner face of the support layer, said power supply part being electrically connected to the current source and to the functional part of the electrical circuit through the support layer;

[0017] - the power supply part is electrically connected to the functional part by at least one connecting element extending into the support layer, said connecting element being formed by a conductive material extending into a through opening formed in the support layer;

[0018] - the functional layer forms a grounded area outside the arranged pattern to protect the electrical circuit formed by the pattern and / or another electrical circuit of the trim element from electrostatic discharges; and

[0019] - the functional layer is formed by a film glued or laminated on at least one part of the inner face and / or on at least part of the outer face of the support layer.

[0020] According to another aspect, the invention relates to a method for producing a packing element as described above, comprising the following steps:

[0021] - provide a support layer,

[0022] - apply a layer of carbon material to at least part of the face external and / or on at least part of the internal face of the support layer,

[0023] - cutting the layer of carbon material over its entire thickness so as to form a pattern comprising at least one conductive zone made of carbon material and at least one non-conductive zone formed by a through opening in the layer of carbon material so as to obtain an electrical circuit,

[0024] - electrically connecting the conductive area of ​​the pattern of the reinforcement layer to a power source.

[0025] According to another characteristic of the method according to the invention, the layer of carbon material is cut by laser attack, chemical attack, milling or mechanical drilling in the carbon material.

[0026] Other aspects and advantages of the invention will appear on reading the following description, given by way of example and with reference to the appended drawings, in which:

[0027] [Fig-1] - [Fig.l] is a schematic cross-sectional representation of part of a functional element according to one embodiment of the invention,

[0028] [Fig.2] - [Fig.2] is a schematic sectional representation of a part of a functional element according to another embodiment of the invention,

[0029] [Fig.3] - [Fig.3] is a schematic sectional representation of a part of a functional element according to yet another embodiment of the invention,

[0030] [Fig.4] - [Fig.4] is a schematic cross-sectional representation of a part of a functional element during a step of a method of producing the trim element,

[0031] [Fig.5] - [Fig.5] is a schematic sectional representation of a part of a functional element during another step of a method of producing the trim element,

[0032] [Fig.6] - [Fig.6] is a schematic sectional representation of a part of a functional element during yet another step of a method of producing the trim element,

[0033] [Fig.7] - [Fig.7] is a schematic representation of another example of a pattern made in a functional layer of a packing element according to the invention to form a force sensor,

[0034] [Fig.8] - [Fig.8] is a schematic representation of another example of a pattern produced in a functional layer of a filling element according to the invention to form a tactile surface,

[0035] [Fig.9] - [Fig.9] is a schematic representation of another example of a pattern made in a functional layer of a packing element according to the invention to form part of a capacitive circuit,

[0036] [Fig. 10] - [Fig. 10] is a schematic representation of another example of a pattern made in a functional layer of a packing element according to the invention to form another part of a capacitive circuit,

[0037] [Fig. 11] - [Fig. 11] is a schematic representation of the capacitive circuit formed by the patterns of Figs. 9 and 10,

[0038] [Fig. 12] - [Fig. 12] is a schematic representation of a plurality of patterns made in a functional layer of a packing element according to the invention in order to perform several functions on the external surface of the packing element,

[0039] [Fig. 13] - [Fig. 13] is a schematic cross-sectional representation of the operation of a pattern made in a functional layer forming a capacitive circuit to form a proximity sensor,

[0040] [Fig. 14] - [Fig. 14] is a schematic cross-sectional representation of a packing element comprising a pressure sensor according to one embodiment, and

[0041] [Fig. 15] - [Fig. 15] is a schematic sectional representation of a packing element comprising a pressure sensor according to another embodiment.

[0042] With reference to Figs. 1 to 3, a vehicle trim element 1 is described comprising at least one support layer 2, one decorative layer 4 and one layer functional 6. Such a trim element is for example intended to form a door panel, a dashboard or central console covering or other.

[0043] The support layer 2 is arranged to give its shape and its mechanical characteristics to the trim element 1, in particular its rigidity. The support layer 2 is thus for example made of a substantially rigid material for a door panel, such as a plastic or composite material. According to one embodiment, the support layer 2 is made of a composite material comprising natural fibers in a polypropylene matrix, also known under the name NFPP for “Natural Fiber PolyPropylene”. The natural fibers are for example chosen from flax, hemp, kenaf and / or wood.The support layer 2 is for example formed by thermocompression in a pressing tool having the desired shape of the support layer 2, which corresponds to the shape of the filling element 1. Thus, the support layer 2 has for example a three-dimensional shape with raised areas. By way of example, the support layer 2 may for example comprise an area projecting relative to the rest of the support layer 2 to form an armrest.

[0044] Alternatively, the support layer 2 is made by injecting plastic material, such as polypropylene (PP), polycarbonate acrylonitrile butadiene styrene (PC ABS), or other, into a molding cavity having the desired shape. According to another variant, the support layer 2 is obtained by additive manufacturing to the desired shape. The support layer 2 comprises an internal face 8, intended to extend on the side of the part of the vehicle on which the trim element is to be installed, such as the door of the vehicle in the case of a door panel, and an external face 10, opposite the internal face 8, and intended to be turned towards the passenger compartment of the vehicle.

[0045] The decorative layer 4 extends on the side of the external face 10 of the support layer 2 over at least a portion thereof. The decorative layer 4 is arranged to give its appearance and feel to the upholstery element 1. The decorative layer 4 is thus, for example, made of a flexible or rigid material, having a particular appearance and / or feel that it is desired to give to the upholstery element 1. Thus, the decorative layer 4 is, for example, made of a textile material, a plastic material, a woody material, leather or imitation leather or other. The decorative layer 4 is shaped to the external face 10 of the support layer 2, that is to say that it substantially matches the shape of the external face 10 in the area of ​​the support layer 2 that it covers. According to one embodiment, the decorative layer 4 covers the entire support layer 2.

[0046] The decorative layer 4 comprises an internal face 12 extending opposite the external face 10 of the support layer 2 and an external face 14 extending towards the outside of the trim element 1 and forming the external surface of the trim element 1, that is to say forming the visible part of the trim element 1 from the passenger compartment of the vehicle. The external face 14 may include decorative patterns or indications intended for a user to indicate the presence of a functional area for example, as will be described later. Alternatively or additionally, the decorative layer 4 may be translucent, at least in certain areas, to allow light to pass from the internal face 12 to the external face 14, which makes it possible to backlight these areas in order to inform a user of the presence of a functional area for example.

[0047] According to one embodiment, the decorative layer 4 is fixed directly onto the support layer 2 (Figs. 3 and 6), in which case a bonding layer 16, for example glue, an adhesive, a heat-activatable polypropylene film, extends between the external face 10 of the support layer 2 and the internal face 12 of the decorative layer 4. Alternatively, a functional layer 6 is interposed between the support layer 2 and the decorative layer 4, in which case a bonding layer 16 extends between the functional layer 6 and the internal face of the decorative layer 4 (Figs. 1 and 2). It is understood that the decorative layer 4 can be fixed in another way suitable for the support layer 2 or for the functional layer 6. Such a fixing can for example be obtained by sewing, by overmolding, by welding or by foaming a connecting layer, in particular depending on the materials used to produce the support layer 2 and / or the decorative layer 4.

[0048] According to one embodiment, the trim element 1 is devoid of decorative layer 4 and the external surface 14 of the trim element is formed by the external face of the support layer 2 and / or by the functional layer 6 extending over the support layer 2.

[0049] The functional layer 6 is a layer made of a carbon material and comprising at least one pattern 18 allowing the functional layer to confer a particular functionality to the filling element 1, as will be described later. The material is for example in the form of carbon fibers without sizing and / or recycled carbon fibers. The fact of not having sizing makes it possible to improve the electrical properties of the pattern 18. The pattern 18 thus has better conductivity and better continuity of electrical contact after the three-dimensional shaping of the filling element, as will be described later. The functional layer 6 has for example a thickness substantially between 20 μm and 200 μm. In addition, the carbon layer may also comprise polypropylene, for example in an amount less than or equal to 40% by weight of the composition of the functional layer.

[0050] According to one embodiment, the functional layer 6 is arranged to form a reinforcing layer for the support layer 2. Such a reinforcing layer improves the mechanical properties of the filling element, particularly in terms rigidity and self-supporting, more particularly when the support layer 2 is made of a composite material. According to one embodiment, the functional layer 6 is formed by a film glued or laminated on the support layer 2. In this case, the functional layer does not necessarily form a reinforcing layer for the support layer 2.

[0051] The functional layer 6 extends over at least a portion of the inner face 8 or over at least a portion of the outer face 10 of the support layer 2 depending on the function to be performed, as will be described later. In the case of a reinforcing layer, the functional layer 6 is more particularly applied to areas of the support layer 2 requiring reinforcement. According to one embodiment, the functional layer 6 extends over the entire surface of the inner face 8 or the outer face 10 of the support layer. According to one embodiment, the functional layer 6 is applied directly to the support layer 2, that is to say there is no intermediate layer between the support layer 2 and the functional layer 6. The functional layer 6 is shaped to the part of the face of the support layer 2 that it covers, that is to say the reinforcing layer 6 matches the shape of this part of the face of the support layer 2.

[0052] The pattern 18 comprises at least one conductive area 20 formed by the carbon material of the functional layer 6 and at least one non-conductive area 22 formed by a through opening in the functional layer 6. The shapes of the conductive area 20 and the non-conductive area 22, examples of which are shown in Figs. 7 to 12, are arranged to form at least part of a functional electrical circuit performing a particular function when the conductive area 20 is supplied with electricity. In other words, the pattern 18 is such that the functional layer 6 defines at least one electrical circuit making it possible to perform the desired function when the circuit is supplied with power. Depending on the desired function, several distinct conductive areas 20 and non-conductive areas 22 may be provided.

[0053] The functions performed by the electrical circuit(s) are functions of interaction with a passenger of the vehicle on the external surface 14 of the trim element. In other words, the functions performed are part of the human-machine interface of the vehicle, the passengers of the vehicle being able to interact with the external surface 14 of the trim element to activate, control and / or influence the function performed by the electrical circuit formed by the pattern 18.

[0054] According to the embodiment shown in [Fig.l], the pattern 18 is arranged to form an electrical circuit on the external face 10 of the support layer 2, between the latter and the decorative layer 4, for example a resistive circuit as will be described later.

[0055] According to the embodiment shown in Figs. 2 and 14, the pattern 18 is arranged to form a capacitive circuit with another pattern extending on the opposite face of the support element 2. In this case, the filling element comprises a second functional layer, the pattern 18 of which forms, with the pattern 18 of the first functional layer, a capacitive circuit. More particularly, the filling element 1 comprises an internal functional layer 26 extending over at least a portion of the internal face 8 of the support layer 2 and an external functional layer 28 extending over at least a portion of the external face 10 of the support layer 2, the pattern 18 of the internal functional layer 26 and the pattern 18 of the external functional layer 28 extending opposite each other.The shape of the patterns 18 is arranged so that the capacitive circuit generates a capacitive field towards the outer surface 14 of the trim element 1 when the patterns are supplied with electricity. Thus, the patterns 18 of the inner functional layer 26 and of the outer functional layer 28 form a touch-sensitive surface on the outer surface 14 of the trim element opposite the pattern 18 of the outer functional layer 28. Such a touch-sensitive surface can be used to control the operation of certain functions of the vehicle, such as the actuation of the window glass in the case of a door panel, when a user touches the touch-sensitive surface or another adjustment. It is understood that when two functional layers 6 are provided on the opposite faces of the support layer 2, these do not necessarily have the same dimensions.In particular, the dimensions of one of the two functional layers may be limited to those strictly necessary to form the pattern 18 opposite the pattern 18 formed in the other functional layer.

[0056] According to the embodiment of [Fig. 14], the support layer 2 is flexible and is capable of being crushed when pressure is exerted on the external surface of the packing element 1, for example by a finger as shown in [Fig. 14]. The crushing is reversible, that is to say that the support layer 2 is elastically deformable, when the pressure ceases to be exerted. According to this embodiment, the patterns 18 formed on the internal functional layer 26 and on the external functional layer 28 form a capacitive circuit 27 whose capacitance varies as a function of the distance separating the internal functional layer 26 from the external functional layer 28. Thus, by crushing the support layer 2 at the right angle of the patterns 18, the patterns are brought closer to each other, which varies the capacitance of the capacitive circuit 27 and makes it possible to produce a force sensor in the packing element.The force with which the pressure is exerted can be determined by measuring the capacitance of the capacitive circuit 27, this increasing as the distance separating the patterns decreases, that is to say as the force exerted on the external surface 14 increases.

[0057] As a variant of this embodiment, the force sensor can be made by two functional layers 6 extending on the external face 10 of the support layer 2 and separated by a flexible layer 29 as shown in [Fig. 15]. In this case, it is the flexible layer 29 which is elastically deformable so as to allow the patterns 18 of the two functional layers 6 to be brought together when pressure is exerted on the external surface 14 of the trim element to vary the capacitance of a capacitive circuit 27 formed between the two functional layers 6. The flexible layer 29 is for example a layer of foam and / or a layer of adhesive material. The flexible layer 29 electrically insulates the two functional layers 6.

[0058] An example of the shape of patterns 18 making it possible to produce a so-called “multi-touch” capacitive circuit is shown in Figs. 9 to 11. In [Fig. 9], the pattern 18 formed in the external functional layer 28 is shown. The pattern 18 comprises several substantially parallel lines of conductive zones 20 separated by lines of non-conductive zones 22. Each conductive zone 20 is formed by a succession of blocks 30 connected in series and connected to a terminal 24. In [Fig. 10], the pattern 18 formed in the internal functional layer 26 is shown. The pattern 18 comprises several substantially parallel columns of conductive zones 20 separated by columns of non-conductive zones 22. Each conductive zone 20 is formed by a succession of blocks 32 connected in series and connected to a terminal 24. In [Fig. 1 1], the capacitive circuit formed by the patterns 18 of Figs. 9 and 10 is shown.The pattern 18 of the internal functional layer 26 is arranged on the internal face 8 of the support layer 2 in such a way that the blocks 32 extend opposite the through openings of the non-conductive zones 22 of the pattern 18 of the external layer 28 which is arranged on the external face 10 of the support layer 2. The capacitive circuit thus has a checkerboard shape in which the boxes of one color extend on one face of the support layer 2 and in which the boxes of the other color extend on the other face of the support layer 2.

[0059] Alternatively, according to the example of pattern 18 shown in [Fig. 8], a capacitive circuit formed on a single face of the support layer 2 can be produced to form a touch surface called a “touch slider” on the external surface 14 of the trim element. This pattern 18 extends for example on the external face 10 of the support layer 2 only. It comprises a row of conductive zones 20, each connected to a terminal 24 and having an arrowhead shape. The conductive zones 20 are separated by non-conductive zones 22 also in the shape of an arrowhead and delimiting the conductive zones 20. Such a touch surface is for example used by sliding the finger along the row, for example to change the value of a parameter controlled by a user, such as a temperature, sound volume, ventilation flow, window opening or other.

[0060] In [Fig. 12], a pattern 18 is shown forming a proximity sensor around of the outer surface 14 of the trim element. Such a pattern 18 comprises several conductive zones 20 formed of distinct tracks separated by non-conductive zones 22. The tracks are each connected to a connector 25 at their end, forming a connection terminal 24. Such a proximity sensor makes it possible to detect the presence of a part of the body of a passenger, such as a hand or a finger, in an area around the outer surface 14 of the trim element 1, in order to detect the movements of this part of the body in the detection zone. According to the embodiment of [Fig. 12], the pattern 18 surrounds a central zone 27 which can be used to form another electrical circuit performing a different function, such as the functions described previously, and / or to receive a display device, making it possible to display information on the outer surface 14 of the trim element 1, or be left as is.The pattern 18 is surrounded by the remainder of the reinforcing layer 6 which can be connected to the connector 25 to provide grounding of the electrical circuits, as will be described later. As shown in [Fig. 13], when a user brings a finger close to the outer surface 14 of the trim element 1 in the vicinity of the proximity sensor, the capacitance of the capacitive circuit forming this sensor increases and by measuring this capacitance, it is possible to determine the presence of the finger in the detection zone and the distance separating the finger from the outer surface 14 of the trim element.

[0061] According to the embodiment shown in [Fig. 3], the pattern 18 is arranged to form a flexible resistive circuit. In this case, the functional layer 6 extends over the inner face 8 of the support layer 2. By flexible, it is meant that the resistive circuit is capable of deforming when pressure is applied to the outer surface 14 of the trim element, this deformation modifying a characteristic value of the circuit so as to allow detection of pressure on the outer surface 14. Thus, the pattern 18 forms a pressure sensor on a portion of the outer surface 14 of the trim element opposite the pattern 18. Such a sensor can for example be used to control the operation of certain functions of the vehicle, in particular by forming for example a switch or a continuous force sensor. Where appropriate, the decorative layer 4 is applied directly to the outer face 10 of the support layer 2.A form of pattern 18 for producing such a force sensor, or force gauge, is shown in [Fig.7]. The pattern 18 comprises a conductive zone 20 extending between two terminals 24 and in the form of a strip following a particular path. The strip is delimited by a non-conductive zone 22. Alternatively, the pattern performs the function of an on / off switch or button or . well a caption proportional to the force applied, depending for example on the organ controlled by this circuit.

[0062] It is understood that the same functional layer 6 or two functional layers on each face may comprise several patterns 18 in different zones in order to perform different functions on the different corresponding zones of the external surface 14 of the filling element 1. Thus, for example, a pattern 18 forming a heating resistive circuit is provided on the external face 10 of the support layer 2 in a first zone and another pattern 18 forming a pressure sensor is provided on the internal face 8 of the support layer 2 in a second zone, the pressure sensor making it possible, for example, to control the heating surface. Alternatively, several distinct patterns forming distinct electrical circuits are, for example, provided. In certain cases, the functions have been described with reference to a particular positioning of the functional layer on one of the faces of the support layer 2.It is understood, however, that the same functions could be achieved by placing the functional layer 6 on the other side of the support layer 2.

[0063] The or each pattern 18 is supplied with electricity by at least one current source (not shown) electrically connected to the conductive zone(s) 20 of the pattern 18, for example connected to each terminal 24 of the patterns 18. The current source is connected to the conductive zone 20 for example by an electrical cable 34 connected directly (Figs. 2 and 3) or by means of an electrical connector 36 to the conductive zone 20 of the pattern 18 ([Fig.l]). When the pattern 18 extends over the outer face 10 of the support layer 2, the electrical cable 34 passes for example through a through opening 38 made in the support layer 2, the conductive zone 20 of the pattern 18 extending for example over a part or around a part of the through opening 38. When a connector 36 is provided, this extends for example in the through opening 38 from the inner face 8 to the outer face 10 of the support layer 2, as shown in [Fig.l].The electrical cable 34 is then connected to the electrical connector 36 on the side of the inner face 8 of the support layer 2 and the electrical connector 36 is connected to the conductive zone 20 on the side of the outer face 10 of the support layer 2. The electrical cable 34 is for example connected to the electrical system of the vehicle which then forms the current source. When a functional layer 6 is provided on each side of the support layer 2, each functional layer 6 is supplied with current by one or more current sources.

[0064] In a variant not shown, the pattern 18 forms a functional part of an electrical circuit on one of the faces of the support layer 2, for example the external face 10. The electrical circuit then comprises a power supply part extending over the other face of the support layer 2, for example the inner face 8. The functional part has the desired shape for the electrical circuit to perform the desired function, as described above, and the power supply part comprises the connection terminals 24 of the circuit which are electrically connected to the current source. The power supply part is electrically connected to the functional part by at least one connection element extending into the support layer 2. The connection element is for example formed by a conductive material filling an opening passing through the support layer 2 between the power supply part and the functional part of the circuit. The power supply part may be formed by a pattern extending into a functional layer 6 extending on the other face of the support layer 2.Alternatively, when only one functional layer 6 is provided, only the tracks forming the power supply portion may be formed from carbon material on the other face of the support layer 2. Such an embodiment may facilitate the connection of the electrical circuit to the current source when the circuit extends mainly on one face of the support layer 2 while the current source is arranged on the side of the other face of the support layer 2.

[0065] As indicated previously, the functional layer 6 may form a grounding zone outside the pattern(s) 18 formed in this functional layer 6. Such a grounding zone makes it possible to protect the electrical circuit(s) from electrostatic discharges likely to damage the electrical circuit(s). To do this, the grounding zone is electrically connected to the electrical circuit(s), for example at a connector, as shown in [Fig. 12]. Alternatively or additionally, the functional layer 6 allows the grounding of one or more electrical circuits of the trim element 1 distinct from the circuit(s) formed in the functional layer 6. Thus, the circuit(s) provided on a printed circuit board may be protected from electrostatic discharges by connecting the grounding output of the printed circuit board to the grounding zone of the functional layer 6.

[0066] According to a particular embodiment, the trim element may comprise a transparent or translucent coating extending over the decorative layer 4 or over the support layer and / or the functional layer 6, through which the decorative layer 4 or the support layer and / or the functional layer 6 is visible. Such a coating is for example a varnish or a translucent film, for example based on polypropylene, making it possible to protect the decorative layer 4 or the support layer 2 and / or the functional layer and in particular to prevent degradation of the pattern(s) 18.

[0067] The packing element described above makes it possible to integrate one or more functions into the surface of the packing element in a simple, reliable and economical manner. integrating the electrical circuit(s) enabling these functions to be carried out in a functional layer 6 of the support layer 2.

[0068] A method of producing a packing element according to an embodiment described previously will now be described with reference to Figs. 4 to 6.

[0069] First of all, a support layer 2 is provided on which a layer of carbon material 40 is deposited. The layer of carbon material 40 is deposited on all or part of the inner face 8 or outer face 10 of the support layer 2 depending on the desired function, as described above. According to one embodiment, a layer of carbon material 40 is deposited on the inner face 8 and another is deposited on the outer face 10 of the support layer 2. In [Fig. 4], the layer of carbon material 40 extends over the inner face 8 of the support layer 2, for the purpose of producing a pressure sensor, as described with reference to Figs. 3 and 7. The deposition of the layer of carbon material 40 is for example obtained by assembling a mat of carbon fibers and polypropylene fibers resulting from a needling process and applied to the support layer 2.According to one embodiment, the carbon material layer 40 forms a reinforcing layer for the support layer 2.

[0070] As shown in [Fig. 5], the pattern 18 is then produced in the carbon material layer 40. To do this, at least one through opening is formed right through in the carbon material layer 40 in order to produce the non-conductive zone 22. By "right through", it is meant that the carbon material layer 40 is cut over its entire thickness. The shape of the through opening(s) in the carbon material layer 40 defines the shape of the pattern 18 and of the conductive zone(s) 20 thereof. According to the embodiment of [Fig. 5], the carbon layer 40 is hollowed out by means of laser radiation 42, which makes it possible to define the shape of the pattern 18 very precisely. Alternatively, the carbon material layer 40 is cut by chemical etching, by milling or by mechanical drilling in the carbon material. As described previously, several patterns 18 may be provided in the functional layer 6.

[0071] It is understood that the pattern(s) 18 could also be produced before the application of the layer(s) of carbon material 40 on the support layer 2.

[0072] If necessary, the decorative layer 4 is then fixed, for example by gluing, to the support layer 2 and / or to the functional layer 6, as shown in [Fig.6].

[0073] Where appropriate, a transparent or translucent coating is applied to the decorative layer 4 or to the support layer 2 and / or to the functional layer 6.

[0074] The conductive zone(s) 20 are then connected to one or more current sources, for example when mounting the trim element 1 on the vehicle. When an electrical connector 36 is provided, it is for example introduced into a through opening 38 previously made in the support layer 2.

[0075] A three-dimensional shaping step of the support layer 2 may be provided to give the trim element the desired shape. This step may be carried out before or after the assembly of the decorative layer 4 and / or the application of the coating.

[0076] The method is therefore particularly simple and inexpensive to implement. In addition, the positioning of the pattern(s) 18 can be ensured precisely.

Claims

Claims

1. Vehicle trim element (1) comprising at least one support layer (2), comprising an inner face (8) and an outer face (10), and at least one functional layer (6) of carbon material extending over at least a portion of the inner face (8) and / or over at least a portion of the outer face (10) of the support layer (2), characterized in that at least a portion of said functional layer (6) defines at least one pattern (18) comprising at least one conductive zone (20) of carbon material and at least one non-conductive zone (22) formed by a through opening in the functional layer (6), said conductive zone (20) being powered by a current source electrically connected to the conductive zone (20), the pattern (18) forming at least a portion of an electrical circuit arranged to perform an interaction function with a passenger of the vehicle on an outer surface (14) of the trim element,the opening being cut in the functional layer (6) and defining the shape of the pattern (18), said pattern (18) being surrounded by the remainder of the functional layer (6).,

2. A trim element according to claim 1, further comprising a decorative layer (4) extending opposite the external face (10) of the support layer (2) and forming the external surface (14) of the trim element.

3. A packing element according to claim 1, wherein the outer surface (14) of the packing element is formed by the support layer (2) and / or by the functional layer (6).

4. A trim element according to any one of claims 1 to 3, comprising an outer functional layer (6, 28) extending over at least a portion of the outer face (10) of the support layer (2) and an inner functional layer (6, 26) extending over at least a portion of the inner face (8) of the support layer (2), the patterns (18) of the outer (28) and inner (26) functional layers (6) forming a capacitive circuit so as to form a touch surface on at least a portion of the outer surface of the trim element.

5. A packing element according to any one of claims 1 to 3, wherein the pattern (18) of the functional layer (6) forms a flexible resistive circuit so as to form a pressure sensor on at least a portion of the external surface of the packing element.

6. A packing element according to any one of claims 1 to 3, wherein comprising an outer functional layer (6, 28) and an inner functional layer (6, 26), the outer functional layer (28) being separated from the inner functional layer (26) by the support layer (2) or by a flexible layer (29), the patterns (18) of the outer functional layer (28) and the inner functional layer (26) forming a capacitive circuit (27) whose capacitance varies according to the distance separating the outer functional layer (28) from the inner functional layer (26), said distance varying by reversible crushing of the support layer (2) or the flexible layer (29) when pressure is exerted on the outer surface (14) of the packing element.

7. A packing element according to any one of claims 1 to 6, wherein the support layer (2) is made of a composite material comprising natural fibers in a polypropylene matrix.

8. A packing element according to any one of claims 1 to 7, wherein the pattern (18) is formed in a functional layer (6) extending on the outer face (10) of the support layer (2), said pattern forming a functional part of an electrical circuit, said electrical circuit comprising a power supply part extending on the inner face (8) of the support layer (2), said power supply part being electrically connected to the current source and to the functional part of the electrical circuit through the support layer (2).

9. A packing element according to claim 8, wherein the power supply portion is electrically connected to the functional portion by at least one connection element extending into the support layer (2), said connection element being formed by a conductive material extending into a through opening formed in the support layer (2).

10. A packing element according to any one of claims 1 to 9, wherein the functional layer (6) forms a grounded area outside the pattern (18) arranged to protect the electrical circuit formed by the pattern (18) and / or another electrical circuit of the packing element from electrostatic discharges.

11. A packing element according to any one of claims 1 to 10, wherein the functional layer (6) is formed by a film glued or laminated on at least part of the inner face (8) and / or on at least part of the outer face (10) of the support layer (2).

12. Method for producing a packing element according to any one of claims 1 to 11, comprising the following steps: - providing a support layer (2), - applying a layer of carbon material (40) to at least a portion of the external face (10) and / or to at least a portion of the internal face (8) of the support layer (2), - cutting the layer of carbon material (40) over its entire thickness so as to form a pattern (18) comprising at least one conductive zone (20) of carbon material and at least one non-conductive zone (22) formed by a through opening in the layer of carbon material so as to obtain an electrical circuit, - electrically connecting the conductive zone (20) of the pattern (18) of the functional layer (6) to a current source.

13. A method of production according to claim 12, wherein the carbon material layer (40) is cut by laser etching, chemical etching, milling or mechanical drilling in the carbon material.

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