Multilayer assembly, particularly for vehicles

Abstract

The invention relates to a multilayer assembly (160), particularly intended for installation inside the passenger compartment of a vehicle, especially a motor vehicle, comprising: A heating structure (7) arranged to emit heat towards a functional face (2), said functional face (2) being configured to diffuse the received heat outwards from the multilayer assembly (160), for example towards an area of ​​a vehicle passenger compartment; A layer (163) of at least one heat-sensitive material, in particular a thermochromic material, arranged to change its appearance, in particular its color and / or opacity, depending on the heat emitted by the heating structure (7). Abstract figure: Figure 13

Description

Title of the invention: Multilayer assembly, particularly for vehicles

[0001] The present invention relates to a multilayer assembly, particularly intended for installation inside the passenger compartment of a vehicle. The vehicle may be of a land, sea or air type.

[0002] Heating panels are known which comprise a plurality of electrodes configured to deliver heat by Joule effect by supplying an electric current to a conductive coating. See, for example, US2016 / 0059669.

[0003] Furthermore, it is known to use lighting devices in the passenger compartment of motor vehicles. These interior lighting devices are increasingly in demand by automobile manufacturers.

[0004] There is a need for devices that can perform different functions, including a heating function, and that are relatively comfortable.

[0005] The invention thus relates to a multilayer assembly, in particular intended to be installed inside the passenger compartment of a vehicle, in particular a motor vehicle, comprising: - A heating structure arranged to emit heat towards a functional face, said functional face being configured to diffuse the received heat towards the outside of the multilayer assembly, for example towards an area of ​​a vehicle passenger compartment, - A layer of at least one thermosensitive material, in particular a thermochromic material, arranged to change its appearance, in particular its color and / or opacity, depending on the heat given off by the heating structure.

[0006] By thermosensitive material, we mean here a material capable of changing its appearance depending on the surface temperature on which it is deposited. This could be, for example, a paint, an ink, or a coating.

[0007] The "opacity" aspect refers to the ability of a material to change from a transparent to an opaque state in response to a temperature variation. This change in opacity allows for modulation of the visibility or aesthetic appearance of the panel.

[0008] A thermochromic material is defined here as a material capable of changing color depending on the surface temperature on which it is deposited. Examples include paint, ink, and coatings.

[0009] The multilayer assembly according to the invention advantageously forms a heating panel or a component as defined below.

[0010] Thanks to the invention, when integrating a heating panel, for example, into a trim panel of a motor vehicle, it is possible to provide passengers with visual feedback regarding the surface temperature of the heating panel. This helps prevent any surprise or discomfort in the event of contact with a hot surface. The invention thus proposes an appearance that changes according to the surface temperature, to inform passengers of the hot / cold state of the multilayer assembly. In this way, the invention makes it possible to warn passengers that the panel has exceeded a predetermined temperature threshold, and to warn them of potential burns or to indicate that the heating is functioning correctly.

[0011] In one aspect according to the invention, the assembly comprises at least one light structure arranged to emit light towards the functional face, said functional face being configured to diffuse the received light outwards from the multilayer assembly, for example towards an area of ​​a vehicle passenger compartment.

[0012] In one aspect according to the invention, the thermochromic material comprises at least one thermochromic pigment.

[0013] In one aspect according to the invention, the thermochromic material comprises a mixture of at least two thermochromic pigments.

[0014] In one aspect according to the invention, the thermochromic material is arranged to change color depending on the temperature of the heating structure. For example, when the temperature of the heating structure becomes greater than or equal to a predetermined threshold temperature, the thermochromic material is arranged to change color, and when the temperature of the heating structure falls below said threshold temperature, the thermochromic material returns to its original color.

[0015] According to one aspect of the invention, the thermochromic material is arranged to change color depending on the temperature of the heating structure. For example, the thermochromic material has a first color when the temperature of the heating structure is within a first temperature range, and a second color when the temperature of the heating structure is within a second temperature range. For example, the first temperature range is a temperature range covering all temperatures less than or equal to the threshold temperature, and the second temperature range is a temperature range covering all temperatures above the threshold temperature.

[0016] For example, when the first temperature range is lower than the second temperature range, the first color has a blue tint and the second color has a red or orange tint. This is only a non-limiting example; other colors / appearances can be considered.

[0017] In one aspect according to the invention, the thermochromic material has a first color when the temperature of the heating structure is in a first temperature range, a second color when the temperature of the heating structure is in a second temperature range, and a third color when the temperature of the heating structure is in a third temperature range.

[0018] For example, when the first temperature range is lower than the second temperature range, the first color has a blue tint, the second color has an orange tint, and the third color has a red tint.

[0019] In one aspect according to the invention, the thermochromic material is arranged to form a first color pattern when the temperature of the heating structure is in a first temperature range and a second color pattern different from the first pattern when the temperature range of the heating structure is in a second temperature range.

[0020] In one aspect according to the invention, the assembly includes a decoration visible from inside the passenger compartment, this decoration being for example a covering of the passenger compartment, such as for example a fabric, a leather or an aesthetic coating.

[0021] In one aspect according to the invention, the heating structure and the decoration form stacked layers.

[0022] In one aspect according to the invention, the thermosensitive material is deposited on a surface of the decoration of the multilayer assembly, said decoration surface being the surface visible from inside the passenger compartment.

[0023] In one aspect according to the invention, the thermochromic material has the same color as the decorative surface on which it is deposited when the heating structure is at a temperature within a first temperature range, and a different color from the decorative surface when the temperature of the heating structure is within a second temperature range. Thus, the thermochromic material is not visible when the temperature of the heating structure is in this first temperature range and becomes visible when the temperature of the heating structure moves into the second temperature range.

[0024] In one aspect according to the invention, the thermochromic material is configured to change from a color identical / similar to that of the decorative surface to a different color.

[0025] In another aspect according to the invention, the heat-sensitive material changes from a transparent state to a colored state, in particular with a color different from that of the decoration. In this case, the decoration, located under the heat-sensitive material, becomes visible or not depending on the transparency of the heat-sensitive material.

[0026] In one aspect according to the invention, the multilayer assembly is configured to achieve a color change by modifying the opacity of the pigment of the thermosensitive material.

[0027] In one aspect according to the invention, the multilayer assembly includes a luminous structure arranged to emit light towards the functional face.

[0028] In one aspect according to the invention, the heating structure, the lighting structure and the decoration form stacked layers.

[0029] In one aspect according to the invention, the layer of thermosensitive material is disposed between the light structure and the decorative layer.

[0030] In one aspect according to the invention, the thermosensitive material is applied to a surface of the decorative layer, said surface facing the light structure.

[0031] According to one aspect of the invention, the multilayer assembly comprises a mask made of a material which blocks light from a light structure or modifies the color of the light emitted by the light structure and comprising or not openings to allow this light to pass through according to a pattern conferred by these openings.

[0032] In one aspect according to the invention, said mask is disposed between the layer of thermosensitive material and the decorative layer.

[0033] In one aspect according to the invention, the heat-sensitive material is arranged to be transparent in a first temperature range of the heating structure, and to become more opaque in a second temperature range of the heating structure.

[0034] In one aspect according to the invention, the heat-sensitive material is arranged to allow the light emitted by the light structure to pass through in the first temperature range of the heating structure, and to at least partially block the passage of the light emitted by the light structure in the second temperature range of the heating structure.

[0035] In one aspect according to the invention, the heat-sensitive material is arranged to at least partially prevent the passage of light emitted by the light structure into the first temperature range of the heating structure, and to allow the passage of light emitted by the light structure into the second temperature range of the heating structure.

[0036] In one aspect according to the invention, the layer of thermosensitive material acts as a mask when the temperature of the heating structure is below the threshold temperature.

[0037] In one aspect according to the invention, the layer of thermosensitive material acts as a mask when the temperature of the heating structure is above the threshold temperature.

[0038] The invention also relates to a trim panel, in particular for a motor vehicle, in particular for a passenger compartment, in particular on an interior face of a door, comprising a multilayer assembly as mentioned above.

[0039] The invention also relates to a vehicle comprising at least one multilayer assembly as described above.

[0040] The invention further relates to a vehicle comprising a passenger compartment, said passenger compartment comprising said at least one multilayer assembly as described above.

[0041] In one aspect according to the invention, the vehicle comprises a front-end module, said front-end module comprising the multi-layer assembly.

[0042] In one aspect according to the invention, the heating structure comprises: - at least one resistive layer arranged to produce heat when an electric current passes through that layer, - at least two electrodes in electrical contact with the resistive layer so as to allow an electric current to flow through the resistive layer between these two electrodes.

[0043] According to one aspect of the invention, the luminous structure has at least one region, in particular the entire luminous structure, which is placed between the functional face and the heating structure so that light from this luminous structure reaches the functional face without passing through the resistive layer of the heating structure.

[0044] According to one aspect of the invention, the resistive layer and / or the electrodes of the heating structure are carried by the light structure.

[0045] According to one aspect of the invention, the resistive layer and / or the electrodes of the heating structure are inks that have been deposited, for example by printing or screen printing, on the light structure.

[0046] Thus, the heating and lighting structures are linked, with the lighting structure serving as a support for the heating structure. In this case, the heating structure may lack its own substrate, the lighting structure then serving as a substrate for the resistive layer of the heating structure. The invention can therefore reduce the number of components required for the heating and lighting device. Manufacturing costs can thus be reduced.

[0047] In one example of an implementation of the invention, the electrodes and the resistive layer of the heating structure are formed on one face of the light structure, a face which is opposite to the functional face.

[0048] The face of the light structure that is turned towards the functional face primarily receives the lighting function. The heating function is present on the other face of the light structure.

[0049] Insofar as the luminous structure is of small thickness, in particular less than or equal to 1 mm, this luminous structure does not act as a thermal shield with respect to the heating structure which is adjacent to it, and therefore does not significantly hinder the heating function.

[0050] In another example of an implementation of the invention, the electrodes and the resistive layer of the heating structure are mounted on a dedicated substrate, separate from the light structure.

[0051] According to one aspect of the invention, this substrate is made of a woven or non-woven material.

[0052] According to one aspect of the invention, the electrodes and / or the resistive layer are deposited on the substrate by printing, screen printing or lamination of several materials.

[0053] According to one aspect of the invention, the heating and lighting device includes a decoration visible from inside the passenger compartment, this decoration being for example a covering of the passenger compartment, such as for example a fabric, a leather or an aesthetic coating.

[0054] According to one aspect of the invention, the heating and lighting device includes at least one reflective area arranged to reflect light produced by the light structure towards the functional face.

[0055] According to one aspect of the invention, the reflective zone is present between the light structure and the heating structure.

[0056] According to one aspect of the invention, the reflective area extends continuously, in particular with regard to the entire light structure.

[0057] Alternatively, the reflective area extends discontinuously, in particular by forming one or more discrete reflective patterns.

[0058] According to one aspect of the invention, the reflective area is formed by a reflective layer, in particular of white paint, capable of reflecting light produced by the light structure.

[0059] According to one aspect of the invention, this reflective layer is deposited on the heating structure.

[0060] According to one aspect of the invention, this reflective layer extends, at least in part, over the resistive layer of the heating structure.

[0061] In one aspect according to the invention, the luminous structure comprises a flexible guide sheet including a film made of a material having a refractive index, this material being, for example, a polymer, the film forming a core of the sheet of flexible guidance, core in which light can propagate, this film being interposed between two layers of materials with refractive indices lower than the refractive index of the film material, this luminous structure further comprising at least one optical decoupling element configured to reflect or diffract locally light propagating in the film outwards from the film.

[0062] In one aspect according to the invention, the film has a thickness less than or equal to 1000 micrometers, preferably less than or equal to 800 micrometers, preferably less than or equal to 600 micrometers, preferably less than or equal to 400 micrometers, preferably less than or equal to 300 micrometers, preferably less than or equal to 250 micrometers, preferably less than or equal to 200 micrometers, preferably between 10 micrometers and 250 micrometers.

[0063] Alternatively, the flexible guide sheet has a thickness less than or equal to 1000 micrometers, preferably less than or equal to 800 micrometers, preferably less than or equal to 600 micrometers, preferably less than or equal to 400 micrometers, preferably less than or equal to 300 micrometers, preferably less than or equal to 250 micrometers, preferably less than or equal to 200 micrometers, preferably between 12 micrometers and 250 micrometers.

[0064] The term "flexible guide sheet" refers to the fact that the flexible guide sheet can deform to take on a predetermined shape. For example, when the flexible guide sheet is placed on a curved (e.g., convex) surface, its deformation allows it to conform to this curved surface. The flexible guide sheet has a thin profile such that its flexibility is preserved.

[0065] According to one aspect of the invention, the flexible guide mat has a light-emitting face emitting the light extracted by the optical decoupling element(s).

[0066] In one aspect according to the invention, this light-emitting face has a maximum dimension measured between two of the most distant points of this emission face, a maximum dimension which is at least 10 times greater than the thickness of the film, in particular at least 100 or 1,000 times greater than the thickness of the film.

[0067] For example, this maximum dimension of the light-emitting face is 10 cm, and the thickness of the film is 200 micrometers, which represents a factor of 500 between these two dimensions.

[0068] According to one aspect of the invention, the light-emitting face can have various shapes and dimensions. This light-emitting face can, for example, be polygonal, square, or rectangular. This light-emitting face can have a two-dimensional (2D) or three-dimensional (3D) shape. This face 3D light emission can be configured to fit the shape of an area on a vehicle dashboard.

[0069] According to one aspect of the invention, the flexible guide sheet is transparent in the absence of light guided within it.

[0070] In one aspect according to the invention, the optical decoupling elements are formed of microstructures.

[0071] In the following description, optical decoupling elements will be referred to interchangeably as optical decoupling element or microstructure.

[0072] According to one aspect of the invention, the optical decoupling element(s) are transparent in the absence of guided light in the flexible guide sheet.

[0073] According to one aspect of the invention, the optical decoupling element(s) are configured to reflect light directionally, in particular at an angle substantially perpendicular to the emission face of the flexible guide sheet.

[0074] According to one aspect of the invention, a plurality of optical decoupling elements are made on the film forming the core of the flexible guide sheet.

[0075] According to one aspect of the invention, the optical decoupling elements can be of various shapes and / or sizes.

[0076] According to one aspect of the invention, each optical decoupling element extends over the film with a maximum dimension less than 200 micrometers, in particular less than or equal to 100 micrometers, in particular a dimension less than or equal to 50 micrometers. For example, each optical decoupling element is a pin or bump having a diameter of approximately 50 micrometers and a height of 1 to 2 micrometers.

[0077] According to one aspect of the invention, each optical decoupling element has a circular or polygonal perimeter, for example in triangle, square, rhombus or rectangle.

[0078] According to one aspect of the invention, each optical decoupling element on the film is formed by an inclined or curved facet or a rough facet, produced for example by cutting or by molding or by ablation for example by laser.

[0079] According to one aspect of the invention, the optical decoupling elements, forming microstructures, are arranged in a pattern, so as to form, when light is injected into the luminous structure, a design, for example a logo, one or more writing characters, an image, a symbol or other decorative element.

[0080] According to one aspect of the invention, the optical decoupling elements can be obtained by ultraviolet printing etching.

[0081] According to one aspect of the invention, the optical decoupling elements ensure high transparency of the film. In particular, a transparency of around 97% can be practically achieved by using these microstructures. Alternatively, the film can be semi-transparent. However, a high degree of transparency is preferred according to the invention, in particular greater than 80%.

[0082] The optical decoupling elements, or microstructures, can be distributed with a density that varies, in particular increases, depending on the distance from the light injection point in the film. For example, the further the microstructures are from the light injection point, the more densely they are distributed. Such a distribution advantageously ensures a homogeneous distribution of light intensity over the entire surface of the film.

[0083] According to one aspect of the invention, the optical decoupling elements are integrated into the film.

[0084] In one aspect according to the invention, the film is made of polycarbonate (PC), or polymethyl methacrylate (PMMA), or thermoplastic polyurethane (TUP), or polyethylene terephthalate (PET).

[0085] Generally speaking, the film material is a thermoplastic, a thermoset, a polymer, a high-transmission silicone, a glass, a composite, an alloy or any other material suitable for light transmission.

[0086] In one aspect according to the invention, at least one of the layers adjacent to the film is an adhesive layer which comprises an optically transparent adhesive (or OCA in English for "Optical Clear Adhesive").

[0087] Preferably, this adhesive is chosen to be transparent and to have a different refractive index than that of the film so as to allow total internal reflection in the film.

[0088] In one aspect according to the invention, at least one of the layers adjacent to the film are protective layers, which allow the film to be mechanically protected.

[0089] In one aspect according to the invention, each face of the film is adjacent with an adhesive layer, itself adjacent with a protective layer.

[0090] In addition, at least one of the protective layers may include an anti-UV treatment, enabling the flexible film to be protected against UV rays once the optical decoupling elements, or microstructures, have been etched. Without such UV protection, the pattern projected by the film is likely to degrade over time, particularly when exposed to sunlight.

[0091] For example, the film and the different layers can be assembled by lamination.

[0092] According to one aspect of the invention, the light and heating structures are assembled together by overmolding or by means of a layer of adhesive.

[0093] According to one aspect of the invention, the heating structure comprises an electrode array having a plurality of distribution electrodes and a plurality of contact electrodes supplied with electric current by the distribution electrodes.

[0094] The distribution electrodes can be seen as "parent" electrodes and the contact electrodes as "child" electrodes.

[0095] According to one aspect of the invention, the contact electrodes are, at least for some of them, in particular for all the contact electrodes of the electrode array, parallel to each other.

[0096] According to one aspect of the invention, the electrode network comprises distribution electrodes arranged to conduct electric current from an electrical source to the contact electrodes, several contact electrodes connecting to the same distribution electrode.

[0097] According to one aspect of the invention, at least one of the distribution electrodes is straight over at least part of its length, and the contact electrodes which are associated with this distribution electrode connect, for example perpendicularly, to this distribution electrode.

[0098] According to one aspect of the invention, the distribution electrodes may have different shapes, including curved with rounded edges.

[0099] The distribution electrodes may or may not be parallel to each other.

[0100] According to one aspect of the invention, the electrode network comprises at least two distribution electrodes which are parallel to each other over at least part of their length, and their associated contact electrodes are arranged between these two distribution electrodes and are alternated with an inter-distance which decreases in relation to the decrease in voltage present between the pairs of electrodes so as to maintain substantially uniform electrical power between the pairs of contact electrodes.

[0101] According to one aspect of the invention, the electrodes and the resistive layer are carried on a substrate made of a flexible material capable of taking a predetermined shape by deformation, this substrate being in particular also extensible.

[0102] According to one aspect of the invention, the electrodes are deposited on the substrate by printing, screen printing or lamination of several materials.

[0103] According to one aspect of the invention, the resistive layer is deposited on the substrate by printing, screen printing or lamination of several.

[0104] According to one aspect of the invention, the resistive layer is present on one face of the substrate.

[0105] According to one aspect of the invention, the resistive layer is arranged opposite the functional face of said device.

[0106] This non-woven fabric may comprise a mixture of polypropylene and / or polyester fibers. Other fibers may be used, for example natural fibers.

[0107] The wires forming the substrate may be extensible, or not.

[0108] According to one aspect of the invention, the substrate can be a sheet of flexible plastic or a foam such as TPU (thermoplastic polyurethane).

[0109] According to one aspect of the invention, the substrate has an area of ​​at least 10 cm2, or at least 50 cm2, or at least 500 cm2.

[0110] According to one aspect of the invention, the electrodes are made of conductive material, in particular metallic such as ink charged with conductive particles, in particular silver or copper particles.

[0111] According to one aspect of the invention, the electrodes are metallic adhesive tapes, for example made of copper.

[0112] According to one aspect of the invention, the resistive layer is a continuous layer.

[0113] Alternatively, the resistive layer comprises a plurality of discrete resistive elements forming this layer.

[0114] According to one aspect of the invention, these discrete resistive elements form repeating patterns.

[0115] According to one aspect of the invention, the heating and lighting device includes a decoration visible from inside the passenger compartment, this decoration being for example a covering of the passenger compartment, such as for example a fabric, a leather or an aesthetic coating.

[0116] According to one aspect of the invention, the heating structure, the lighting structure and the decoration form stacked layers.

[0117] The device according to the invention thus makes it possible to perform, in addition to the heating and lighting functions, a decoration function, for example with a predetermined leather or fabric area, visible from the passenger compartment.

[0118] According to one aspect of the invention, the heating and lighting device includes a mask made of a material that blocks light from a light structure and comprising openings to allow this light to pass through according to a pattern conferred by these openings.

[0119] The invention also relates to a vehicle interior component, comprising a heating and lighting device as mentioned above.

[0120] According to one aspect of the invention, the component is selected from one of the following passenger compartment components: - a component designed to be integrated into a vehicle door, - a component designed to be integrated into a dashboard, - a component for cladding a cellar door, - a component for the roof lining or passenger compartment roof, - an armrest trim component, - a component of a glove box, - a pillar cladding component.

[0121] In one aspect according to the invention, the luminous structure is placed on the outer face of the decoration layer, with a texture layer and / or additional protection for the finish superimposed on said luminous structure.

[0122] According to one aspect of the invention, the passenger compartment component which includes the heating and lighting device is independent of a vehicle seat.

[0123] According to one aspect of the invention, the passenger compartment component which includes the heating and lighting device is arranged to heat by thermal radiation or by thermal conduction or thermal contact, and not by heating by heat transported by air in forced motion within the passenger compartment.

[0124] In particular, the heating and lighting system is not traversed by any airflow intended to cool or heat the passenger compartment. Preferably, the heating and lighting system is separate from any air movement system such as a vehicle's heating, ventilation and / or air conditioning (HVAC) unit.

[0125] According to one aspect of the invention, the passenger compartment component comprises successively the following elements: - a support bracket, in particular made of plastic material, - optionally a layer of foam, specifically designed to provide a soft touch, - the heating and lighting system, - a decoration visible from inside the passenger compartment, this decoration being for example a trim of the passenger compartment, such as for example a fabric, a leather or an aesthetic covering, this decoration being arranged to allow light from the heating and lighting system to pass through.

[0126] According to another aspect of the invention, the passenger compartment component comprises successively the following elements: - a support bracket, in particular made of plastic material, - the heating and lighting system, - a layer of foam, specifically arranged to provide a soft touch, - a decoration visible from inside the passenger compartment, this decoration being for example a trim of the passenger compartment, such as for example a fabric, a leather or an aesthetic covering, this decoration being arranged to allow light from the heating and lighting system to pass through.

[0127] According to another aspect of the invention, the passenger compartment component comprises successively the following elements: - the heating and lighting system, - a support bracket, notably made of plastic material, designed to allow light from the heating and lighting device to pass through, - optionally a layer of foam, specifically designed to provide a soft touch, - a decoration visible from inside the passenger compartment, this decoration being for example a trim of the passenger compartment, such as for example a fabric, a leather or an aesthetic covering, this decoration being arranged to allow light from the heating and lighting system to pass through.

[0128] The support bracket is arranged in particular to carry the different layers before the assembly of the component with a part of the vehicle, for example with a door or a roof of the vehicle.

[0129] Other features, details and advantages of the invention will become apparent from the description given below by way of example in conjunction with drawings in which:

[0130] - Fig. 1 is a schematic representation of a vehicle interior automobile equipped with a heating and lighting system according to an embodiment of the invention,

[0131] - Fig. 2 is a schematic, cross-sectional representation of the device heating and lighting according to an example of an embodiment of the invention;

[0132] - Fig. 3 is a schematic representation of a luminous structure according to the invention;

[0133] Fig. 4 is another schematic representation of a light structure according to the invention from a top view;

[0134] Fig. 5 is another schematic representation of a light structure according to the invention from a side view;

[0135] - Fig. 6 is a schematic representation of a heating structure of the heating and lighting system of the [Fig.2];

[0136] - Fig. 7 is a schematic representation of a heating structure according to another example of the realization of the invention;

[0137] - Fig. 8 is a schematic, cross-sectional representation of a device heating and lighting according to another embodiment of the invention;

[0138] - Fig. 9 is a schematic, cross-sectional representation of a device heating and lighting according to yet another example of an embodiment of the invention;

[0139] - Fig. 10 is a schematic, cross-sectional representation of a device heating and lighting according to yet another example of an embodiment of the invention;

[0140] - Fig. 11 is a schematic, cross-sectional representation of a device heating and lighting according to another embodiment of the invention, incorporating a reflective zone;

[0141] - Fig. 12 is a schematic, cross-sectional representation of a device heating and lighting according to yet another embodiment of the invention, incorporating a reflective zone;

[0142] - Fig. 13 is a schematic cross-sectional representation of an assembly multilayer according to an example of an embodiment of the invention;

[0143] - Fig. 14 is a schematic representation of a trim panel with the multilayer assembly of [Fig. 13];

[0144] - Fig. 15 is a schematic cross-sectional representation of an assembly multilayer according to another embodiment of the invention;

[0145] - Fig. 16 is a schematic representation of a trim panel with another multilayer assembly according to the invention.

[0146] Figure 1 shows a passenger compartment 100 of a motor vehicle V. The doors 101 and the roof 102 of the passenger compartment are also shown. Seats 103 for passengers are also visible.

[0147] In the example described, heating and lighting devices 1 are integrated into the roof 102 of the passenger compartment. These devices 1 can also be integrated into a door 101.

[0148] The heating and lighting device 1 according to the invention can be implemented in different ways.

[0149] In the example illustrated in [Fig.2], the heating and lighting device 1 is integrated into a component 104 fixed to an internal door structure 105 and this component 104 comprises, in a stacking arrangement, successively: - a support bracket 5, which, in the example described, is a structural part made of translucent plastic material, or of transparent plastic material, - a layer of flexible material 6, here a layer of foam, arranged to give the heating and lighting device 1 a soft feel, this layer 6 being able to be omitted if necessary, - a heating structure 7, described in detail below, of the heating and lighting device 1, - a luminous structure 8 capable of emitting visible light, described in detail below, from the heating and lighting device 1, - a decor 9 which can be of textile, leather, wood or plastic type.

[0150] In the example described, the elements 5 to 9 are laminated together before being fixed onto the door structure 105.

[0151] The device 1 includes a functional face 2 towards which heat H produced by the heating structure 7 and light L produced by the lighting structure 8 can be sent, this functional face 2 being configured to diffuse the heat and light thus received towards the outside of the heating and lighting device 1, in the direction of an area of ​​a vehicle passenger compartment.

[0152] The functional face 2 is formed on the decoration 9 which is turned towards the vehicle's passenger compartment.

[0153] In the example described with reference to [Fig.2], the heating structure 7 and the light structure 8 are made as two separate layers and assembled together.

[0154] The heating and lighting device 1 has a panel shape and is flexible, namely it can be conformed to take a predetermined shape.

[0155] The luminous structure according to the invention is shown in figures 3 to 5.

[0156] The visible light emitted by the luminous structure 8 is light visible to the eye human.

[0157] Figure 3 shows a luminous structure 8 comprising a flexible guide sheet 110, said sheet comprising a film 111 in its core. This film 111 is capable of receiving light rays through a light injection edge 114 and of reflecting the light rays in the direction along the Ox axis substantially perpendicular to the surface of the flexible guide sheet 111 through a light-emitting face.

[0158] A flexible guide sheet is defined as an optical guiding element in which one dimension is much smaller than the other two dimensions in space, for example, smaller by one or more orders of magnitude. Here, we consider a flexible guide sheet whose thickness along the Ox axis is at least two orders of magnitude smaller than its dimensions along the Oxy plane in which the flexible guide sheet 110 extends.

[0159] The film 111 comprises a set of optical decoupling elements 113 formed by microstructures on one face of the film 111 extending along the Oy axis. The microstructures 113 are capable of reflecting light rays guided in the flexible film 111 away from the flexible guide sheet 110, in particular in a direction along the Ox axis perpendicular to the surface of the sheet 110.

[0160] The film is made of polycarbonate (PC), or polymethyl methacrylate (PMMA), or thermoplastic polyurethane (TUP), or polyethylene terephthalate (PET).

[0161] The flexible film 111 can have a thickness, namely the dimension along the Ox axis, of between 10 and 1000 micrometers. More precisely, the thickness of the flexible film 111 can be between 50 and 1000 micrometers, for example between 100 and 500 micrometers, preferably 150 micrometers. Alternatively, it is the guide sheet flexible 110 which has a thickness between 10 and 1000 micrometers. More precisely, the thickness of the flexible film 111 can be between 50 and 1000 micrometers, for example between 100 and 500 micrometers, preferably 150 micrometers.

[0162] The aforementioned materials, combined with a low thickness as described above, allow the production of a flexible and transparent film 111. Other materials may be used for the composition of the flexible film 111. However, according to the invention, it is preferable to use deformable and transparent materials.

[0163] The flexible guide sheet 110 further comprises one or two protective layers 112.1 and 112.2, which provide mechanical protection for the flexible film 111. In addition, the protective layers 112.1 and 112.2 may include a UV-resistant treatment, enabling the flexible film 110 to be protected from UV radiation after the microstructures 113 have been etched. Without such UV protection, the pattern projected by the flexible guide sheet 110 is likely to degrade over time, particularly when exposed to sunlight.

[0164] Since the guide sheet 110 is flexible, it is not necessarily contained in a plane but can be curved or shaped, depending on the position in which it is placed and the mechanical stresses applied to it.

[0165] The propagation of light rays in the flexible film 111 is done by total internal reflection thanks to the difference between the refractive index of the flexible film 111 and that of at least one adjacent layer, here an adhesive layer applied on at least one face of the flexible film.

[0166] In the illustrated example, the flexible film 111 is joined to the protective layers 112.1, 112.2 by gluing. Specifically, an adhesive layer 115.1, 115.2, here a layer of glue, is located between the flexible film 111 and each protective layer 112.1, 112.2, on both sides of the flexible film 111 to ensure that the protective layers 112.1, 112.2 adhere to the flexible film 111.

[0167] The chosen adhesive is transparent and has a different refractive index than the flexible film so as to allow total internal reflection within the flexible film 111. In other words, due to the difference in refractive index, light rays propagating within the flexible film undergo total internal reflection upon encountering the interface between the flexible film and the adhesive layer at an angle of incidence less than normal. Thus, the guiding sheet 110 is capable of guiding light by total internal reflection, for example, from an input zone, here the slice 114, to an output zone.

[0168] A coating of optical decoupling elements 113 formed by microstructures can be applied to one of the faces of the flexible film 111, in particular the light-emitting face, or integrated into the flexible film 111. The coating of microstructures 113 may, in particular, have a thickness along the Ox axis of less than 20 micrometers. These optical decoupling elements are configured 113 to reflect light directionally, in particular at an angle substantially perpendicular to the emission face of the flexible guide sheet 110.

[0169] Such microstructures 113 have, for example, a general bump-like shape, on which light rays are reflected in a direction along the Ox axis. Such microstructures 113 are suitable for causing the light rays exiting the flexible film 111 to form a pattern. To this end, the microstructures 113 are, for example, etched by ultraviolet printing, so as to reflect the light rays through the surface of the flexible film according to the desired pattern. For example, the microstructures 113 are distributed so as to project a homogeneous light over the entire surface of the flexible film 111. This is referred to as a homogeneous pattern in what follows.

[0170] Microstructures 113 are understood to be structures, or irregularities in the flexible film, whose dimensions are less than a few micrometers. Microstructures thus also include nanometric structures. Such microstructure sizes 113 make it possible to ensure high transparency of the flexible film 111. In particular, a transparency of around 97% can be practically achieved by using microstructures 113.

[0171] Alternatively, the flexible guide sheet can be semi-transparent. In this embodiment, the transparency is greater than or equal to 80%.

[0172] Advantageously, the microstructures 113 can be distributed along the Oy axis such that the linear density of microstructures 113 is proportional to the distance from the light injection slice 114 through which the light rays injected by an injection element 120 are received. In other words, the further the microstructures 113 are from the light injection slice 114, the more densely they are grouped. Such a distribution advantageously ensures a homogeneous distribution along the Y axis of the light intensity of the pattern emitted by the flexible guide sheet 110.

[0173] As illustrated in [Fig. 4], the flexible film 111 may include a mixing zone 111.2 and a light-emitting zone 111.1 provided with microstructures 113. The mixing zone 111.2 is positioned upstream of the light-emitting zone along the direction of light ray propagation within the light-guiding sheet 110. The light-emitting zone 111.1 is integrated into a region 1110 of the sheet 110. The light injected into the light-guiding sheet 110 via the slice 114 is mixed in the light-mixing region 111.2 to obtain better light homogeneity. The light then propagates through the light-emitting zone 111.1, through which the light exits the light-guiding sheet 110 along the Ox direction.

[0174] The light structure 8 comprises: - at least one group 120 of 120.1 light injection elements, and - a light guiding sheet 110 forming a flexible surface film.

[0175] Group 120 and the light injection elements 120.1 are shown in Figures 4 and 5.

[0176] The light injection elements form bands.

[0177] In a non-limiting embodiment, when there are multiple groups 120, the number of groups 120 is between two and twenty. When there are multiple groups 120, each group 120 is configured to illuminate a different region 1110 in the light guide sheet 110. Illumination is understood to mean the act of transmitting or injecting light into a defined region.

[0178] A group 120 comprises one or more light injection elements 120.1. In this example, a group 120 comprises several light injection elements 120.1. The number of light injection elements 120.1 that can be included in a group is therefore between three and ten. More specifically, in the example of Figures 3 to 5, the flexible guide sheet 11 comprises a group 120 with ten light injection elements 120.1.

[0179] The group 120 is coupled with at least one light source 20 so as to receive the light rays R emitted by said source in each of the light injection elements.

[0180] Since the light injection elements came from the material with the light guide sheet 110, the light rays R will propagate by total internal reflection in the light injection elements 120.1 of the group 110 so as to bring light to the light guide sheet 110 which is adjacent and attached to the light injection elements 120.1 and which will thus illuminate the region or regions 1110 of the light guide sheet 110.

[0181] As illustrated in Figures 4 and 5, a light injection element 120.1, otherwise called coupling bar 120.1, or light bar 120.1, or simply bar 120.1, is configured to receive the light rays R emitted by the light source 20 which propagate and are reflected in full in said light injection element 120.1. The light injection element 120.1 has a square cross-section.

[0182] Figure 5 illustrates the flexible guide sheet of Figure 3 or 4 with the light injection elements 120.1 of group 120 unfolded. In Figure 5, the light injection element 120.1 has a length Lh and a width W. In a non-limiting embodiment, the length Lh is between 100 and 500 mm. In a non-limiting embodiment, the width W is between 1 and 20 mm.

[0183] We will now describe, in more detail, the heating structure 7.

[0184] As illustrated in [Fig.6], this heating structure 7 comprises a resistive layer 51 arranged to produce heat when an electric current passes through this layer.

[0185] The heating structure 7 further includes two distribution electrodes 52, which are in electrical contact with the resistive layer 51 so as to allow an electric current to flow through the resistive layer 51 between these two electrodes 52.

[0186] These electrodes 52 have parallel sections 53 between which is the resistive layer 51, and transverse sections 54 which are connected to electrical supply wires 55.

[0187] The electrodes 52 and the resistive layer 51 are carried on a substrate 58 made of a flexible material capable of taking a predetermined shape by deformation, this substrate being in particular also extensible.

[0188] The electrodes 52 are deposited on the substrate 58 by printing, screen printing or lamination of several materials.

[0189] The electrodes 52 are made of conductive material, in particular metallic such as ink charged with conductive particles, in particular silver or copper particles.

[0190] Furthermore, the resistive layer 51 is deposited on the substrate by printing, screen printing or lamination of several materials.

[0191] The resistive layer 51 is present on one face of the substrate 58, opposite the luminous structure 8.

[0192] The nonwoven fabric may comprise a mixture of polypropylene and / or polyester fibers. Other fibers may be used, for example natural fibers.

[0193] Alternatively, the substrate 58 can be a flexible plastic sheet or a foam such as TPU (thermoplastic polyurethane).

[0194] The substrate 58 has a thickness of less than 1 mm, and a surface area of ​​at least 10 cm², or at least 50 cm², or at least 500 cm². Advantageously, the thickness of the substrate is less than 500 micrometers, preferably less than 200 micrometers, inclusive.

[0195] In another example illustrated in [Fig.7], the heating structure 7 can be replaced, in the heating and lighting device 1, by a heating structure 70 which includes an electrode array 71 as described below.

[0196] This electrode network 71 comprises two straight distribution electrodes 72 and a plurality of contact electrodes 73 supplied with electric current by the distribution electrodes 72.

[0197] The distribution electrodes 72 can be viewed as “parent” electrodes and the contact electrodes 73 as “child” electrodes.

[0198] Several contact electrodes 73 are connected to the same distribution electrode 72, along a right angle.

[0199] The contact electrodes 73 are parallel to each other, and form pairs each associated with a resistive layer 75.

[0200] These layers 75 are separated from each other and form several heating zones, for example with repeating patterns.

[0201] In another example not shown, the distribution electrodes 72 may have different shapes, including curved with rounded edges.

[0202] In another example of an implementation of the invention illustrated in [Fig.8], the resistive layer 51 and the electrodes 52 of the heating structure 7 are carried by the light structure 8.

[0203] The resistive layer 51 and the electrodes of the heating structure 7 are inks that have been deposited, for example by printing or screen printing, on the light structure 8.

[0204] In this case, the heating structure 7 may be without its own substrate, the light structure then serving as a substrate for the resistive layer 51 of the heating structure 7.

[0205] The electrodes 52 and the resistive layer 51 are formed on one face of the luminous structure 8, face which is opposite to the functional face 2.

[0206] In general, the device 1 can be used to form a component 104 selected from one of the following passenger compartment components: a component designed to be integrated into a vehicle door, a component designed to be integrated into a dashboard, a component for a footwell cabinet trim, a component for the roof lining or passenger compartment roof, an armrest trim component, a component of a glove box, a pillar cladding component.

[0207] Fig. 1 shows the use case in a vehicle roof.

[0208] The passenger compartment component 104 which includes the heating and lighting device is independent of a seat 103 of the vehicle.

[0209] The passenger compartment component 104 which includes the heating and lighting device 1 is arranged to heat by thermal radiation or by thermal conduction or thermal contact, and not by heating by heat transported by air in forced motion within the passenger compartment.

[0210] In another example of an implementation of the invention, illustrated in [Fig.9], the passenger compartment component 130 comprises successively the following elements: - a support bracket 5, which, in the example described, is a structural part made of translucent plastic material, or of transparent plastic material, - a heating structure 7 of the heating and lighting device 1, - a luminous structure 8 capable of emitting visible light, - a layer of flexible material 6, here a layer of foam, arranged to to give the heating and lighting device 1 a soft feel to the touch, this layer 6 being able to be omitted where appropriate, - a decor 9 which can be of textile, leather, wood or plastic type.

[0211] In this configuration, layer 6 is adjacent to decor 9.

[0212] In another example of an implementation of the invention, illustrated in [Fig. 10], the passenger compartment component 140 comprises successively the following elements: - a heating structure 7 of the heating and lighting device 1, - a luminous structure 8 capable of emitting visible light, - a support bracket 5, which, in the example described, is a piece of structure made of translucent plastic material, or of transparent plastic material, - a layer of flexible material 6, here a layer of foam, arranged to give the heating and lighting device 1 a soft feel, this layer 6 being able to be omitted if necessary, - a decor 9 which can be of textile, leather, wood or plastic type.

[0213] In all embodiments of the invention, the light structure 8 is placed between the heating structure 7 and the functional face 2.

[0214] We will now describe other embodiments according to the invention in which the heating and lighting device includes a reflective zone 40 arranged to reflect light produced by the light structure 8 towards the functional face 2.

[0215] In the example illustrated in [Fig. 11], the reflective area 40 is present between the light structure 8 and the heating structure 7.

[0216] The reflective area 40 extends continuously, in relation to the entire luminous structure 8.

[0217] In the example of [Fig. 11], the reflective area 40 is formed by a reflective layer 41, here of white paint, capable of reflecting light produced by the light structure 8.

[0218] This reflective layer 41 is deposited on the heating structure 7.

[0219] This reflective layer 41 extends, at least in part, over the resistive layer 51 of the heating structure 7.

[0220] Thus, for example, white paint can be deposited onto the ink forming the resistive layer 51, this ink itself being present on a substrate 58. The reflective area 40 can be manufactured simultaneously with the heating structure 7, as an additional layer on this heating structure. This allows for a relatively simple manufacturing process for the reflective area and provides a wide choice of materials for the reflective layer.

[0221] In another embodiment of the invention illustrated in [Fig.12], the reflective zone 40 is formed by the resistive layer 51 of the heating structure 7, which resistive layer 51 contains compounds to perform the heating function and compounds to perform the light reflection function.

[0222] The resistive layer 51 can thus, for example, contain a resistive ink mixed with reflective compounds such as a white coloured material.

[0223] The advantage of this method is that it avoids the need for an additional layer to perform the light reflection function. The resistive layer 51 performs the dual function of heating and reflection.

[0224] Another example of implementation of the invention has been described with reference to [Fig. 13].

[0225] In this example, we have a multilayer assembly 160, comprising component 104, already described above, which comprises, according to a stacking, successively: - a support bracket 5, which, in the example described, is a structural part made of translucent plastic material, or of transparent plastic material, - a layer of flexible material 6, here a layer of foam, arranged to give the heating and lighting device 1 a soft feel, this layer 6 being able to be omitted if necessary, - a heating structure 7, described in detail below, of the heating and lighting device 1, - a luminous structure 8 capable of emitting visible light, described in detail below, from the heating and lighting device 1, - a decor 9 which can be of textile, leather, wood or plastic type.

[0226] Only decoration 9 is represented on this [Fig. 13], layers 5 to 8 are omitted as they are already described in previous examples.

[0227] The multilayer assembly 160 is integrated into a trim panel 173, in particular of a motor vehicle, in particular for a passenger compartment, in particular on an interior face of a door.

[0228] The heating structure 7 is arranged to emit heat towards a functional face 162, said functional face 162 being configured to diffuse the heat received towards the outside of the multilayer assembly 160, for example towards an area of ​​a vehicle passenger compartment.

[0229] The multilayer assembly 160 further includes a layer 163 comprising at least one thermosensitive material, here a thermochromic material, arranged to change its appearance, in particular its color and / or opacity, depending on the heat emitted by the heating structure 7.

[0230] A thermochromic material is a material capable of changing color depending on the surface temperature on which it is deposited. Examples include paint, ink, and coatings.

[0231] The multilayer assembly 160 according to the invention advantageously forms a heating panel.

[0232] The light structure 8 is arranged to emit light towards the functional face 162, said functional face 162 being configured to diffuse the received light outwards from the multilayer assembly 160, for example towards an area of ​​a vehicle passenger compartment.

[0233] The thermochromic material comprises at least one thermochromic pigment, or the thermochromic material comprises a mixture of at least two thermochromic pigments.

[0234] The thermochromic material is arranged to change color depending on the temperature of the heating structure 7. For example, when the temperature of the heating structure 7 becomes greater than or equal to a predetermined threshold temperature, the thermochromic material is arranged to change color, and when the temperature of the heating structure 7 falls below said threshold temperature, the thermochromic material returns to its original color.

[0235] The thermochromic material is arranged to change color depending on the temperature of the heating structure 7. For example, the thermochromic material has one color when the temperature of the heating structure 7 is within a first temperature range, and a second color when the temperature of the heating structure 7 is within a second temperature range. For example, the first temperature range is a temperature range covering all temperatures less than or equal to the threshold temperature, and the second temperature range is a temperature range covering all temperatures above the threshold temperature.

[0236] For example, when the first temperature range is lower than the second temperature range, the first color has a blue tint and the The second color has a red or orange tint. This is just one example; other colors / appearances can be considered.

[0237] The thermochromic material has a first color when the temperature of the heating structure 7 is in a first temperature range, a second color when the temperature of the heating structure 7 is in a second temperature range and a third color when the temperature of the heating structure 7 is in a third temperature range.

[0238] For example, when the first temperature range is lower than the second temperature range, the first color has a blue tint, the second color has an orange tint, and the third color has a red tint.

[0239] The thermochromic material is arranged to form a first color pattern when the temperature of the heating structure 7 is in a first temperature range and a second color pattern different from the first pattern when the temperature range of the heating structure 7 is in a second temperature range.

[0240] As can be seen in [Fig. 14], the multilayer assembly 160 includes a decoration 9 visible from inside the passenger compartment, this decoration 9 being for example a trim of the passenger compartment.

[0241] This decoration 9 includes, for example, a fabric or leather 180 which covers or envelops a layer of decorative material 178.

[0242] The heating structure 7 and the decor 9 form stacked layers.

[0243] The thermochromic material layer 163 is deposited on a surface 182 of the decoration material layer 178 of the multilayer assembly 160, said decoration surface 182 being the surface visible from inside the passenger compartment.

[0244] The thermochromic material has the same color as the decor surface 182 on which it is deposited when the heating structure 7 has a temperature within a first temperature range when the heating structure 7 is off and remains at room temperature (see [Fig. 14], on the right with the mention OFF), and a different color from the decor surface 182 when the temperature of the heating structure 7 is within a second temperature range when the heating structure 7 is switched on and becomes hot (see [Fig. 14], on the left with the mention ON).

[0245] Thus, the thermochromic material is not visible when the temperature of the heating structure 7 is in this first temperature range and becomes visible by forming patterns 175 when the temperature of the heating structure 7 passes into the second temperature range (see [Fig. 14], on the left with the mention ON).

[0246] The threshold temperature between the two ranges is for example set at 50°C or 60°C.

[0247] Reasons 175 include: - a continuous surface covering all or part of the functional face 162 (see [Fig. 15]), - discrete patterns composed of spaced dots, lines, or segments, - specific symbols, such as arrows, pictograms or logos, - a variety of designs, - texts or alphanumeric characters providing information about the state or function of the surface, - or any combination of the previous patterns.

[0248] These patterns 175 can be configured to vary in size, color, or intensity depending on the temperature reached by the heating structure 161

[0249] The thermochromic material is configured to change from a color identical / similar to that of the decor surface 182 to a different color.

[0250] Alternatively, the heat-sensitive material changes from a transparent state to a colored state, in particular with a color different from that of the decoration 9. In this case, the decoration 9, located under the heat-sensitive material, becomes visible or not depending on the transparency of the heat-sensitive material.

[0251] The multilayer assembly 160 is configured to achieve a color change by modifying the pigment opacity of the thermosensitive material.

[0252] The layer 163 of thermosensitive material is deposited on the decoration layer 9, drawing patterns.

[0253] In the example of [Fig. 15], the thermosensitive material is applied to a surface of the decor layer 9, said surface facing the light structure 8. The layer 163 of thermosensitive material is deposited between the light structure 8 and the decor layer 9, forming a continuous layer.

[0254] The multilayer assembly 160 includes a mask 185 made of a material which blocks the light from the light structure 8 or modifies the color of the light emitted by the light structure 8 and includes or does not include openings to allow this light to pass through according to a pattern conferred by these openings.

[0255] The mask 185 is disposed between the layer of thermosensitive material 163 and the decoration layer 9.

[0256] The heat-sensitive material is arranged to be transparent in a first temperature range of the heating structure 7, and to become opaque in a second temperature range of the heating structure 7.

[0257] The heat-sensitive material is arranged to allow the light emitted by the luminous structure 8 to pass through in the first temperature range of the structure heating structure 7, and at least partially block the passage of light emitted by the light structure in the second temperature range of the heating structure 7.

[0258] The invention thus enables the following aspects.

[0259] To change the appearance of the heating element when it is off, a thermochromic pigment is integrated into the trim panel's decoration. This pigment can be applied as ink, paint, directly integrated into the raw plastic material, or by means of other decorating techniques. When the trim panel is heated, the pigment changes color, thus allowing patterns to appear, disappear, or be modified.

[0260] Alternatively, in order to modify the appearance of the heating structure in heating mode, a backlighting device may be provided, being translucent, at least in the areas through which the light must pass. When the trim panel is suitable for backlighting, the decorative layer may include a masking layer. This masking layer advantageously has an opaque coating in areas where no light is desired, and openings in areas where light is to be visible.

[0261] According to one aspect of the invention, one or more layers containing a thermochromic pigment are added to this masking layer in order to modify the light transmission properties of the design. This modification makes it possible to change the shape of the light patterns or to change the color of part (or all) of the illuminated surfaces when the panel temperature increases.

[0262] The features of the different embodiments of the invention described above can be combined with each other, if appropriate.

Claims

Demands

1. Multilayer assembly (160), in particular intended to be installed inside the passenger compartment of a vehicle, in particular a motor vehicle, comprising: - A heating structure (7) arranged to emit heat towards a functional face (2), said functional face (2) being configured to diffuse the heat received towards the outside of the multilayer assembly (160), for example towards an area of ​​a vehicle passenger compartment, - A layer (163) of at least one heat-sensitive material, in particular a thermochromic material, arranged to change its appearance, in particular its color and / or opacity, depending on the heat emitted by the heating structure (7).

2. Assembly according to the preceding claim, comprising at least one light structure (8) arranged to emit light towards the functional face (2), said functional face (2) being configured to diffuse the received light outwards from the multilayer assembly (160), for example towards an area of ​​a vehicle interior.

3. Assembly according to any one of the preceding claims, wherein the thermochromic material comprises at least one thermochromic pigment, or a mixture of at least two thermochromic pigments.

4. An assembly according to any one of the preceding claims, wherein the thermochromic material is arranged to change color as a function of the temperature of the heating structure (7), for example, when the temperature of the heating structure (7) becomes greater than or equal to a predetermined threshold temperature, the thermochromic material is arranged to change color, and when the temperature of the heating structure (7) falls below said threshold temperature, the thermochromic material returns to its original color.

5. Assembly according to any one of the preceding claims, wherein the thermochromic material is arranged to form a first color pattern when the temperature of the heating structure (7) is in a first temperature range and a second color pattern different from the first pattern when the temperature range of the heating structure (7) is in a second temperature range.

6. Assembly according to any one of the preceding claims, wherein the assembly comprises a decoration (9) visible from inside the passenger compartment, this decoration (9) being for example a covering of the passenger compartment, such as for example a fabric, a leather (180) or an aesthetic coating, and the heating structure (7), and the decoration (9) form stacked layers, the heat-sensitive material being deposited on a surface of the decoration (9) of the multilayer assembly (160), said surface of decoration (9) being the surface visible from inside the passenger compartment.

7. Assembly according to any one of the preceding claims, wherein the thermochromic material has the same color as the decorative surface (9) on which it is deposited when the heating structure (7) has a temperature within a first temperature range, and a different color from the decorative surface (9) when the temperature of the heating structure (7) is within a second temperature range.

8. Assembly according to any one of claims 1 to 6, wherein the heat-sensitive material changes from a transparent state to a colored state, in particular with a color different from that of the decoration (9).

9. Assembly according to any one of the preceding claims, wherein the multilayer assembly (160) comprises a mask made of a material which blocks light from light structure (8) or modifies the color of the light emitted by the light structure (8) and comprising or not openings to allow this light to pass through according to a pattern conferred by these openings.

10. Trim panel (173), in particular for a motor vehicle, in particular for a passenger compartment, in particular on an inner face of a door, comprising a multilayer assembly (160) according to any one of the preceding claims.

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