Device for a light module of a motor vehicle

Abstract

The invention relates to a device (1) for a motor vehicle, which device comprises an active liquid crystal film (10) with an active liquid crystal layer (11) covered on either side by an electrically conductive layer (12), each electrically conductive layer (12) being covered, only at an active part of the active film (10), by an electrically insulating protective layer (13), the active film (10) comprising, at a longitudinal end (131), an electrical connection area (130) located outside the active part. At the electrical connection area (130), the electrically conductive layer (12) of the active film (10) is not covered by the protective layer (13). The device (1) has an electrical connector (15) associated with the electrical connection area (130), and mechanically and electrically coupled to the electrically conductive layer (12) via an electrically conductive adhesive (14).

Description

device for a vehicle's lighting module

[0001] The technical context of the present invention is that of lighting and / or signaling modules for motor vehicles. More specifically, the invention relates to a device for a lighting module of a motor vehicle.

[0002] In the prior art, light modules are known to shape a headlight beam used as a high beam or low beam to illuminate a road scene in front of the vehicle, or to shape a signaling beam, such as a position light, brake light, or turn signal, to provide other road users with information about the vehicle's current or future position and / or behavior, or to shape a beam to illuminate the interior of the vehicle. All these beams can also generate a distinctive light signature for the vehicle. Such light modules use various light source technologies to produce the light rays and associated beams, such as light-emitting diodes (LEDs) or liquid crystal displays (LCDs).In particular, these latest liquid crystal-based technologies are used especially for signature lighting modules, in order to highlight lighting specific to the style of the motor vehicle.

[0003] As is known, such devices comprise an active film containing liquid crystals, the active film being electrically polarized via an electrical connector attached to the active film. Specifically, the attachment of such an electrical connector by welding to an electrical connection zone of the active film is known. The electrical connector is applied against the electrical connection zone, and one or more solder points are applied over the electrical connector to connect it to the electrical connection zone.

[0004] This configuration is not optimal and leads to the following drawbacks. First, from a mechanical standpoint, the spot weld attachment is not sufficiently robust and sometimes results in partial or total separation of the electrical connector from the electrical connection area. This separation leads to unwanted malfunctions of the active film and the device. Indeed, in the context of automotive use, the device is subjected to significant and frequent vibrations during vehicle operation; and the spot weld attachment proves insufficiently reliable in the long run.

[0005] Furthermore, from a materials perspective, the spot welding of the electrical connector to the active film's electrical connection zone leads to corrosion problems. Indeed, exposing the electrical connector and solder points to ambient air subjects them to changing climatic conditions that affect the nature of the exposed materials. In this case, excessive humidity in the environment to which the device is exposed, such as that found during winter or rainy weather, leads to chemical alteration of the exposed materials and the onset of corrosion. This corrosion, in turn, leads to a degradation of the electrical coupling between the electrical connector and the active film's electrical connection zone, and / or to a degradation of the mechanical coupling between them.

[0006] The present invention aims to provide a new device to address at least some of the previous problems and to lead to other advantages.

[0007] Another objective of the invention is to make such a device more robust in the face of the environmental conditions to which it is intended to be exposed.

[0008] Another aim of the invention is to offer such a device that is more reliable and more economical.

[0009] Another aim of the invention is to offer such a device that is more robust in the face of the vibratory stimulations to which it is intended to be exposed.

[0010] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a device for a light module of a motor vehicle, the device comprising: - an active liquid crystal film, the active film extending along a longitudinal axis in the form of a multilayer strip stacked one on top of the other in a stacking direction, the multilayer strip comprising an active liquid crystal layer, the active layer being covered by at least one electrically conductive layer, each at least one electrically conductive layer being at least partially covered by an electrically insulating protective layer, the active film comprising, at the level of at least one longitudinal end of the multilayer strip, at least one electrical connection zone at the level of which the at least one electrically conductive layer is not covered by the protective layer;- at least one electrical connector associated with at least one electrical connection zone, each at least one electrical connector comprising at least one electrical conductor, the at least one electrical connector extending across the associated electrical connection zone of the active film, said at least one electrical connector being mechanically and electrically coupled to said electrically conductive layer of said corresponding at least one electrical connection zone by means of an electrically conductive adhesive.

[0011] In other words, an electrically insulating protective layer is applied directly, at least partially, to each of the at least one electrically conductive layers. The electrically conductive layer and its associated electrically insulating protective layer are thus located on the same side of the active liquid crystal layer, and the electrical connection zone where the at least one electrically conductive layer is not covered by the protective layer corresponds to a break in the associated electrically insulating protective layer. Therefore, in the connection zone, the active liquid crystal layer is not exposed to the external environment.

[0012] In the context of the present invention, the longitudinal axis is defined as the principal elongation direction of the active film. The longitudinal axis is typically parallel to the longest side of the active film. For example, in the case of a rectangular active film, the longitudinal axis corresponds to the length of the rectangle forming the active film. Consequently, the longitudinal end of the active film is taken along the longitudinal axis. In other words, the longitudinal end of the active film is located on the side of an edge of said active film, taken along the longitudinal axis. For example, in the case of a rectangular active film, the longitudinal end of the active film, or of the multilayer strip, is located near a short side of the rectangle forming the active film.

[0013] In the context of the present invention, a transverse axis is also defined, taken perpendicular to the longitudinal axis. The transverse axis is considered along a second elongation direction of the active film, thus defining, together with the longitudinal axis, a principal plane of elongation of the active film. The transverse axis is typically perpendicular to the longest side of the active film. For example, in the case of a rectangular active film, the transverse axis corresponds to the width of the rectangle forming the active film. Consequently, lateral adjectives are used along the transverse axis. In other words, a transverse edge of the active film is located on the side of an edge of said active film, taken along the transverse axis. For example, in the case of a rectangular active film, the transverse edge of the active film, or of the multilayer strip, is formed by one of the long sides of the rectangle forming the active film.

[0014] In the context of the present invention, a vertical axis is defined, taken simultaneously perpendicular to the longitudinal and transverse axes. The vertical axis typically corresponds to the stacking direction of the different layers of the active film. In other words, the stacking direction is the direction in which the different layers of the active film are stacked, namely the active layer, at least one electrically conductive layer, and the protective layer. Put another way, the stacking direction is perpendicular to the plane formed by each of the aforementioned layers of the active film. The stacking direction is perpendicular to both the longitudinal and transverse axes of the active film. In the case where the active film is curved, then the stacking direction can be defined by a straight line normal to a point on the active film, that is, perpendicular to a plane tangent to the active film at that point.Typically, the stacking direction corresponds to the smallest dimension of the active film, specifically its thickness.

[0015] In the context of the present invention, an active film forms a strip structure, that is, it has an elongated and flattened shape, although the active film may have a generally planar or curved conformation. Such an active film is called "active" because it is configured to propagate light rays under certain conditions of electrical polarization of the liquid crystals that compose it. The electrical polarization of the active layer is ensured by the electrical connector and the electrically conductive layer. In the context of the present invention, such an active film is transparent when configured in a first electrical polarization of the liquid crystals, and it is diffusing or opaque when said liquid crystals are configured in a second electrical polarization.

[0016] In the context of the present invention, an electrically conductive layer is at least partially covered by an electrically insulating protective layer; that is, it is covered by the protective layer at least outside of an electrical connection zone. In other words, the protective layer extends beyond the electrical connection zone(s) and, possibly, partially over each electrical connection zone(s). Thus, such a protective layer does not extend into each electrical connection zone(s), or it extends over a portion, preferably a peripheral portion, of each electrical connection zone(s).

[0017] In the context of the present invention, an electrically conductive layer is configured to allow the flow of electrons through or along it. For example, such an electrically conductive layer is of the type comprising indium tin oxide or graphene, among other materials. Such an electrically conductive layer allows for the definition of at least two electrical polarization states, which respectively enable the selective control of the following two functional configurations of the active layer: – a configuration in which the liquid crystals are configured so that the active film is transparent; or – a configuration in which the liquid crystals are configured so that the active film is opaque or diffusing.

[0018] To this end, the active layer comprises at least one liquid crystal polymer in order to control the transmission of light rays through the active film. In the context of the present invention, all liquid crystal technologies are addressed.

[0019] In the context of the present invention, such a device comprises one or more electrical connection zones. Each at least one electrical connection zone is located at a longitudinal end of the active film. Each connection zone is associated with an electrical connector. Thus, if the active film has only one electrical connection zone, then the device comprises a single connector associated with that single electrical connection zone. Conversely, if the active film has several electrical connection zones, then the device comprises several electrical connectors, each electrical connector being associated with one of the electrical connection zones.

[0020] In the context of the present invention, the association between an electrical connector and the electrical connection area to which it is attached takes the form of simultaneous electrical and mechanical coupling. To this end, such an electrical connector extends across the corresponding electrical connection area, so that the electrical connector is pressed against said electrical connection area. Consequently, each electrical conductor of the electrical connector is electrically and mechanically coupled to the electrically conductive layer of the active film within the corresponding electrical connection area. Therefore, at least a portion of such an electrical connector extends against and onto the surface of at least a portion of the electrical connection area.The term "across" here refers to a comparison of the electrical connector against the corresponding electrical connection area, relative to the longitudinal axis and / or relative to a transverse axis taken perpendicular to the longitudinal axis, that is to say finally in a plane of elongation of the active film.

[0021] Thus, the device conforming to the first aspect of the invention solves the technical problem by replacing solder points with an adhesive that bonds the electrical connector and the electrical connection area together. The adhesive thus ensures a higher quality mechanical and electrical connection. Indeed, the use of an adhesive, in the broadest sense of the term, is less rigid than a soldered connection. In other words, the adhesive is more flexible than a solder point, and therefore better able to withstand the mechanical vibrations caused by the movement of the motor vehicle.

[0022] Furthermore, using an adhesive, rather than a solder joint, to mechanically couple the electrical connector to the electrical connection area of ​​the active film reduces subsequent exposure to corrosion. Even if the adhesive contains metallic particles for electrical conductivity, these particles are embedded within the adhesive substance, thus protecting them from the surrounding atmosphere and consequently from corrosion. If the adhesive contains no metallic elements, the corrosion problem does not arise.

[0023] The device conforming to the first aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

[0024] The electrically conductive layer is optically transparent to visible light rays. In particular, the electrically conductive layer is optically transparent to light rays propagating through the active liquid crystal layer. Advantageously, the electrically conductive layer is optically transparent to all wavelengths of light rays propagating through the active liquid crystal layer. By "transparent," we understand that the electrically conductive layer has an average transmittance greater than 80% for a visible light spectrum, that is, for wavelengths between 380 nm and 800 nm. Advantageously, the transmittance is greater than 80% for each wavelength of the visible spectrum.However, in the context of the present invention, it is possible that some wavelengths of light rays passing through the active film may not be transmitted or may be transmitted less well than others, without significantly affecting the overall transmission of the active film. Alternatively, the electrically conductive layer is optically transparent to only a portion of the wavelengths of light rays propagating through the liquid crystal active layer.

[0025] - the electrically conductive layer has a thickness on the order of a few micrometers, specifically between 1 and 10 micrometers. The thickness is measured along the stacking direction of the active film;

[0026] The protective layer is configured to shield the active layer and at least one electrically conductive layer, while allowing visible light to pass through, including light propagating through the active layer. In other words, the protective layer is optically transparent to at least some of the wavelengths of light rays propagating through the liquid crystal active layer. "Transparent" means that the protective layer has an average transmittance greater than 80% for a visible spectrum, i.e., for wavelengths between 380 nm and 800 nm. Advantageously, the transmittance is greater than 80% for each wavelength of the visible spectrum.However, in the context of the present invention, it is possible that some wavelengths of light rays passing through the active film may not be transmitted or may be transmitted less effectively than others, without significantly affecting the overall transmission of the active film. Alternatively, the protective layer is optically transparent to only a portion of the wavelengths of light rays propagating through the liquid crystal active layer. The protective layer is electrically insulating. The protective layer thus protects at least one electrically conductive layer from weathering and moisture, for example. By way of non-limiting example, the protective layer may be a plastic film, and in particular a thermoplastic, polycarbonate, or polyethylene terephthalate.

[0027] - the active liquid crystal layer is chosen for example from those comprising liquid crystals dispersed in a polymer (PDLC, English acronym meaning "Polymer Dispersed Liquid Crystal"), or liquid crystals stabilized by a polymer network (PNLC, English acronym meaning "Polymer Network Liquid Crystal") or liquid crystals doped with a dye (DDLC, English acronym meaning "Dye-doped liquid crystal");

[0028] - Each at least one electrical connection zone is defined by the area of ​​the active film along which the electrically conductive layer is made accessible. In particular, in the context of the present invention, an electrically conductive layer is made accessible by any means. According to a first embodiment, such an electrically conductive layer is made accessible at each at least one electrical connection zone by partial lamination of the protective layer, said protective layer extending along the active film up to the at least one electrical connection zone.In other words, during the manufacturing process of the active film, the various constituent layers of the multilayer strip are obtained one on top of the other over the entire surface of the active film, with the exception of the protective layer, which is formed over a smaller area so as to leave the electrically conductive layer exposed at least at one electrical connection zone. According to a second embodiment, such an electrically conductive layer is made accessible at each at least one electrical connection zone by locally removing the protective layer that had been previously deposited over said electrically conductive layer of the active film. This local removal can be carried out by any means, including mechanical machining or chemical abrasion.It is also possible that the two variants are applied to the same active screen, with part of the electrical connection area being obtained by partial lamination of the protective layer, and another part by local removal of this protective layer;

[0029] - at least one electrical connection zone extends from the longitudinal end of the active film for a length of at least 3 mm relative to the longitudinal axis of the active film. The longitudinal end is considered along the longitudinal axis, and the length is measured along said longitudinal axis. This advantageous configuration ensures sufficient mechanical and electrical coupling of the electrical connector on at least one electrical connection zone, without excessively encroaching on the active area of ​​the active film. Alternatively, the invention also provides that at least one electrical connection zone may be located in a central part of the active film, that is, at a distance from each of its longitudinal ends and / or at a distance from each of its lateral ends;

[0030] - relative to a transverse axis of the active film, taken perpendicular to the longitudinal axis and perpendicular to the stacking direction, at least one electrical connection zone extends from one lateral side of the active film to the other, or at least one electrical connection zone extends along a central portion of the active film, that is, a portion located between the two lateral sides but not reaching them. In other words, either at least one electrical connection zone extends across the entire width of the active film, relative to the transverse axis, or at least one electrical connection zone forms a central connection band located at a distance from one or both of the lateral sides of the active film. Alternatively, at least one electrical connection zone may extend from a central portion of the active film to one of the lateral sides of the active film, reaching it.For example, at least one electrical connection zone may extend over only one lateral half of the active film;

[0031] - at least one electrical connector comprises (i) an electrical coupling portion forming an electrical interface with the electrical connection zone of the active film to which it is associated, and more particularly with the electrically conductive layer located in the associated electrical connection zone of the active film, and (ii) a conduction portion extending from the electrical coupling portion and intended to be electrically coupled to a power supply for the device and to provide electrical power to said device. In other words, the conduction portion extends from the electrical coupling portion to allow electrical connection of the device to the power supply. In the context of the present invention, an electrical connector can take any shape.In particular, such an electrical connector is either a simple electrical wire or a ribbon cable comprising a plurality of electrical conductors. If such an electrical connector is a ribbon cable, then the ribbon cable may be flexible or rigid. The terms "flexible" and "rigid" are used here in the context of normal use within the field of the devices of the invention and / or electrical systems. For example, a ribbon cable is considered flexible when, cantilevered and subjected to its own weight, it bends simply under the effect of gravity. Conversely, such a ribbon cable is considered rigid when, cantilevered and subjected to its own weight, it remains in its original shape despite the effect of gravity.In the context of the present invention, electrical conductors form electrical conduction lines – formed by electrically conductive materials – which extend longitudinally to allow the flow of electrons between an electrical connector and a power supply to which the device is intended to be connected. By way of non-limiting example, such electrical conductors are electrical tracks arranged on a substrate of the mat.

[0032] - at least one electrical connector comprises several electrical conductors, the electrical coupling portion and the conduction portion together forming a "T" or "Y" profile, each electrical conductor forming the conduction portion being distributed along the electrical coupling portion, such that the center distance between two adjacent electrical conductors, taken at the level of the conduction portion, is less than the center distance between said two adjacent electrical conductors, taken at the level of the electrical coupling portion. In the context of the present invention, it is understood that the electrical connector has a T profile when the electrical coupling portion and the conduction portion of said electrical connector extend perpendicularly to each other, each of said electrical coupling portion and conduction portion forming one of the branches of the "T".In other words, the electrical conductors extend along the conduction section in a direction of elongation and are distributed across the electrical coupling section over a width, measured perpendicular to the direction of elongation along the electrical coupling section, greater than the width of the conduction section itself. Conversely, an electrical connector is understood to have a "Y" profile when the electrical coupling section has a central recess, that is, aligned with the conduction section, in which the electrical conductors do not extend, and the electrical coupling section has two coupling zones located laterally on either side of the central recess, in which the electrical conductors extend.Naturally, between the conduction section and the electrical coupling section, the electrical connector includes a transition section, with the electrical conductors moving apart along this transition section. The transition section may, for example, have a width that increases towards the electrical coupling section. These advantageous configurations thus allow the geometric shape of at least one electrical connector to be adapted to the shape of the active film, and reduce its size in the conduction section, while providing a wider electrical coupling section to promote good mechanical and electrical coupling in at least one electrical connection zone of the active film. Alternatively, the invention also provides that several electrical connectors can be associated with the same electrical connection zone.

[0033] Preferably, at least one electrical connector covers the entire electrical connection area to which it is associated, such that the electrically conductive layer of the active film is, at the level of said electrical connection area, completely covered by at least one electrical connector. In particular, the coupling area of ​​at least one electrical connector covers the entire associated electrical connection area, such that the electrically conductive layer of the active film is, at the level of the associated electrical connection area, completely covered by at least one electrical connector. This advantageous configuration makes it possible to limit the exposure of at least one electrically conductive layer of the active film to ambient air at the level of at least one electrical connection area.Alternatively, at least one electrical connector partially overlaps the electrical connection area to which it is associated, such that there is a non-zero gap between one side of the at least one electrical connector and one side of the corresponding electrical connection area. Specifically, the coupling area of ​​at least one electrical connector partially overlaps the associated electrical connection area, such that there is a non-zero gap between one side of the at least one electrical connector and the side of the corresponding electrical connection area. This advantageous configuration allows for a larger electrical coupling area and facilitates its bonding to the associated electrical connection area, while reducing the overall size of the electrical connector along its conductive portion to promote greater compactness.The non-zero gap here corresponds to a space along which the electrically conductive layer is not covered by the associated electrical connection area, nor is it covered by at least one electrical connector. By way of non-limiting example, the non-zero gap is less than 5 mm, preferably between 1 mm and 2 mm. The non-zero gap may be located between a longitudinal flank of at least one electrical connector and a longitudinal side of the associated electrical connection area, measured along the longitudinal axis of the active film; and / or the non-zero gap may be located between a lateral flank of at least one electrical connector and a lateral side of the corresponding electrical connection area, measured along the transverse axis of the active film.

[0034] - Optionally, the adhesive includes an electrically conductive adhesive layer extending between at least one electrical connector and the associated electrical connection area, and in particular the electrically conductive layer of the active film. This advantageous configuration facilitates mechanical assembly while optimizing electrical coupling, which then occurs through the deployed adhesive layer. Preferably, the electrically conductive adhesive is of the cross-linking type. By way of non-limiting example, the thickness of the adhesive layer is less than 500 µm;

[0035] - The adhesive layer extends exclusively under at least one electrical connector. This advantageous configuration is more economical in terms of adhesive. Alternatively, the adhesive layer extends over the entire area of ​​at least one electrical connection. In this embodiment, the adhesive layer may extend beyond the electrical coupling portion of the corresponding electrical connector itself. This advantageous configuration is simpler to implement;

[0036] - for gluing at least one electrical connector to at least one electrical connection area with glue, the invention provides for heating in order to lead to cross-linking of the glue;

[0037] - the adhesive comprises a thermoplastic adhesive strip covering at least one electrical connector and sticking it to the associated electrical connection area, and in particular to the electrically conductive layer of the active film. Preferably, the thermoplastic adhesive strip extends between the electrical connector and the electrical connection area;

[0038] - the adhesive is an isotropic electrically conductive adhesive;

[0039] - the adhesive is an anisotropic electrically conductive adhesive;

[0040] - the adhesive is a pressure-sensitive adhesive (PSA);

[0041] - the adhesive is a thermo-sensitive adhesive (TSA for "thermo-sensitive adhesive" in English)

[0042] - the adhesive is an anisotropic conductive film (ACF for "anisotropic conductive film" in English);

[0043] - the adhesive is an anisotropic conductive paste (ACP for "anisotropic conductive paste" in English);

[0044] - Adhesive is an adhesive that may or may not require solidification when attached to an object. The adhesive layer is composed, for example, of an adhesive based on acrylic resin, epoxy resin or similar;

[0045] - for the bonding of at least one electrical connector to the associated electrical connection area with the adhesive strip, the at least one connector is placed and pressed against the corresponding electrical connection area, if necessary with heating, in order to improve mechanical adhesion and electrical conductivity.

[0046] According to a second aspect of the invention, a light module for a motor vehicle is proposed, the light module comprising a device according to the present description and a light source configured to generate light beams in the direction of the device such that said beams pass through said liquid crystal active film in the stacking direction.

[0047] The light module is configured to provide lighting and / or signaling, or interior lighting, for motor vehicles, allowing the generation of, for example, a code and / or a route, and / or a signaling function and / or a daytime running light (commonly called DRL for "Daytime Running Lamp" in English).

[0048] The light source advantageously comprises one or more semiconductor electroluminescent elements.

[0049] The light source is advantageously suited to emit visible light.

[0050] Optionally, the light module includes an optical element for coupling the light rays generated by the light source in order to direct them towards the device.

[0051] Various embodiments of the invention are envisaged, incorporating, according to all their possible combinations, the different optional features described herein.

[0052] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given with reference to the attached schematic drawings on the other hand, in which:

[0053] illustrates a cross-sectional profile view of a first example of an embodiment of a device conforming to the first aspect of the invention;

[0054] illustrates a cross-sectional profile view of a second example of an embodiment of a device conforming to the first aspect of the invention;

[0055] illustrates a top view of a third example of an embodiment of a device conforming to the first aspect of the invention;

[0056] illustrates a top view of a fourth example of an embodiment of a device conforming to the first aspect of the invention;

[0057] illustrates a top view of a fifth example of an embodiment of a device conforming to the first aspect of the invention.

[0058] Of course, the features, variants, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may include only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from prior art.

[0059] In particular, all the variants and embodiments described can be combined with each other if there are no technical obstacles to this combination.

[0060] In the figures, elements common to several figures retain the same reference.

[0061] In the FIGURES described below, a longitudinal axis X, a transverse axis Y, and a vertical axis Z are defined relative to the device 1 according to the invention. In particular: - the longitudinal axis X is defined as the principal elongation direction of an active film 10 forming the device 1. In the FIGURES illustrated below, the longitudinal axis X is shown horizontally and extends from left to right of said FIGURES. The adjectives "front," "front," "rear," and "longitudinal" refer to this longitudinal axis X; - the transverse axis Y extends perpendicularly to the longitudinal axis X. The transverse axis Y is considered along a second elongation direction of the device 1, thus defining, together with the longitudinal axis X, a principal elongation plane of said device 1. In FIGURES 3 to 5 illustrated below, the transverse axis Y is shown horizontally and extends from left to right.The adjective "lateral" refers to the transverse axis Y; the vertical axis Z extends simultaneously perpendicularly to both the longitudinal axis X and the transverse axis Y. The vertical axis Z typically corresponds to the stacking direction of the various layers forming the active film 10 of the device 1. In Figures 1 and 2 below, the vertical axis Z is shown vertically and extends from bottom to top. The adjectives "top," "bottom," "above," "below," "superior," and "inferior" refer to this vertical axis Z.

[0062] With reference to FIGURES 1 to 5, the invention addresses a device 1 for a light module of a motor vehicle, the device 1 comprising: - an active liquid crystal film 10, the active film 10 extending along the longitudinal axis X in the form of a multilayer strip stacked one on top of the other in a stacking direction, the multilayer strip comprising an active liquid crystal layer 11, the active layer 11 being covered by at least one electrically conductive layer 12, each at least one electrically conductive layer 12 being at least partially covered by an electrically insulating protective layer 13, the active film 10 comprising, at the level of at least one longitudinal end 131 of the multilayer strip, at least one electrical connection zone 130 at the level of which the at least one electrically conductive layer 12 is not covered by the protective layer 13;- at least one electrical connector 15 associated with at least one electrical connection zone 130, each at least one electrical connector 15 comprising at least one electrical conductor, the at least one electrical connector 15 extending across the associated electrical connection zone 130 of the active film 10, such that each at least one electrical conductor is electrically coupled to the electrically conductive layer 12, said at least one electrical connector 15 being mechanically and electrically coupled to said electrically conductive layer 12 of said corresponding at least one electrical connection zone 130 via an electrically conductive adhesive 14.

[0063] Thus, according to the invention, and as can be seen in particular in Figures 1 and 2, the multilayer strip forming the active film 10 comprises a plurality of layers 11, 12, 13 stacked one on top of the other along the stacking direction. The stacking direction is represented here along the vertical axis Z. The active film 10 according to the invention comprises two distinct zones along which the conformation of the multilayer strip differs: – at least one active zone in which the active film 10 comprises, along the stacking direction, an active layer 11 sandwiched between two electrically conductive layers 12, themselves capped by a protective layer 13 which extends over a face opposite to the active layer 11 of liquid crystals. Each electrically conductive layer 12 is thus completely covered by the active layer 11 on one side and by the protective layer 13 on the other side, relative to the vertical axis Z.This advantageous configuration protects both the active layer 11 and at least one electrically conductive layer 12 to ensure proper functioning of the active film 10 and to prevent oxidation and / or deterioration of said active layer 11 and / or said electrically conductive layer 12 in the active area of ​​the active film 10; – at least one electrical connection zone 130 in which the active film 10 comprises, depending on the stacking direction, an active layer 11 sandwiched between two electrically conductive layers 12. Each electrically conductive layer 12 thus extends against the active layer 11 on one side but remains free of a protective layer 13 on the other side, relative to the vertical axis Z. This advantageous configuration thus allows for an electrical connection with at least one electrical connector 15 at the associated electrical connection zone 130.Indeed, in order to electrically polarize the active film 10, and more particularly the active layer 11, it is necessary to organize the flow of electrons through at least one electrically conductive layer 12, via said electrical connector 15. Therefore, for this purpose, the electrical connector 15 is electrically and mechanically coupled directly to the electrically conductive layer 12 of the active film 10, in the electrical connection zone 130. Thus, the removal or absence of the protective layer 13 in the electrical connection zone 130 facilitates such coupling.

[0064] As can be seen particularly in Figures 1 and 2, the stacking direction corresponds to the direction in which the active layer 11, the at least one electrically conductive layer 12, and the protective layers 13 of the active film 10 are stacked one on top of the other. In other words, in the example illustrated in Figures 1 and 2, the stacking direction is parallel to the vertical Z-axis.

[0065] In the active film 10 forming the device 1 according to the invention, the different layers 11, 12, 13 of the multilayer strip are bonded to each other and are in contact with each other, in a plane taken perpendicular to the stacking direction of said layers 11, 12, 13. The different layers 11, 12, 13 can be formed by additive synthesis for example, or by thin film deposition processes for example.

[0066] Furthermore, the absence of a protective layer 13 at the level of each at least one electrical connection zone 130 can be obtained by any means, such as for example via mechanical removal, such as by abrasion, scraping or peeling, via chemical removal such as by chemical abrasion, or via a process of forming the different layers 11, 12, 13 which leads to an absence of a protective layer 13 at the level of at least one electrical connection zone 130, such for example by masking techniques, in particular during the formation and / or deposition of the protective layer 13.

[0067] According to the invention, the mechanical and electrical coupling of the electrical connector 15 to the associated electrical connection zone 130 is now ensured by an electrically conductive adhesive 14. Thus, the adhesive 14 simultaneously contributes to mechanically bonding the electrical connector 15 to the electrical connection zone 130, by virtue of its adhesive nature 14, and to electrically coupling said electrical connector 15 to the electrically conductive layer 12 exposed in the associated electrical connection zone 130, by virtue of the chemical nature of said adhesive 14 which enables the transfer of electrons through it.

[0068] In the embodiment illustrated in the figure, the adhesive 14 is of the type of a thermoplastic adhesive strip 14A. The thermoplastic adhesive strip 14A is applied over the electrical connector 15 and extends beyond said electrical connector 15 into the electrical connection area 130, so that the thermoplastic adhesive strip 14A is bonded against said electrical connection area 130. In other words, a first part of the thermoplastic adhesive strip 14A is associated with the electrical connector 15, and in particular with its electrical coupling part 152, and a second part of the thermoplastic adhesive strip 14A is associated with the electrically conductive layer 12 of the electrical connection area 130 to which said electrical connector 15 is coupled.Alternatively, the adhesive 14 in the form of a thermoplastic adhesive strip 14A can be placed in an intermediate position between the electrically conductive layer 12 and the coupling portion of the adjacent electrical connector 15. In this case, one face of the adhesive 14 extends over the electrical connection area 130, so as to be bonded to the electrically conductive layer 12, and the electrical coupling portion 152 of the associated electrical connector 15 is applied against the other face of the adhesive 14 in order to adhere to it.

[0069] In the embodiment illustrated in Figure 1, the adhesive 14 is of the type of a glue layer 14B. The glue layer 14B is applied beneath the electrical connector 15 and extends over the electrical connection area 130. In other words, the glue layer 14B extends between the electrical connector 15, and in particular its electrical coupling portion 152, and the electrically conductive layer 12 of the electrical connection area 130 to which said electrical connector 15 is coupled. Advantageously, the adhesive 14 of the type of a glue layer 14B is of the thermosetting type, the polymerization of the adhesive 14 being achieved by heating.

[0070] In both cases, the adhesive 14 is of the electrically conductive type in order to promote the transfer of electrons from the electrical connector 15 to the electrically conductive layer 12 of the electrical connection area 130, or vice versa.

[0071] Furthermore, in both cases, the adhesive 14 is preferably of the reticular type in order to facilitate the application of said adhesive 14 and to reduce the drying time of the glue layer 14B or the setting time of the adhesive thermoplastic strip 14A.

[0072] The position of each electrical connection zone 130 on the active film 10 can be arbitrary. In particular, as seen in the embodiments illustrated in FIGURES 3 to 5, the electrical connection zones 130 are located near a longitudinal end 131 of the active film 10. Preferably, the active film 10 has two electrical connectors 15, each located at an opposite longitudinal end 131 of the active film 10. This advantageous configuration allows the electrical connector(s) to be placed outside an area of ​​interest of the active film 10, in order to maximize the formation of a light function by the device 1. The area of ​​interest of the active film 10 corresponds here to the part of the active film 10 that is intended to form a light signature or, more generally, a light signal.Obviously, the invention also provides that the electrical connection area 130 can be located on the side of a lateral edge 132 of the active film 10, relative to the transverse axis Y.

[0073] In addition, the dimensions of each connection zone can be arbitrary. Naturally, the invention aims to reduce the dimensions of the connection zone as much as possible in order to maximize the luminous function produced by the active film 10. In the embodiments illustrated in Figures 3 and 4, each connection zone is located at a central portion of the active film 10, relative to the transverse axis Y. In other words, each connection zone extends along a median longitudinal axis X of the active film 10, such that a lateral side 133 of the connection zone is located at a distance from a lateral edge 132 of the active film 10. This advantageous configuration reduces the overall size of the electrical connection zone 130 on the active film 10.In contrast, in the embodiment illustrated in the figure, the connection area located on the side of the longitudinal end 131 on the left of the figure extends from and between the two lateral edges 132 of the active film 10, so that said connection area extends over the entire width of the active film 10. This advantageous configuration makes it possible to maximize the mechanical and electrical coupling between the electrical connector 15 and the associated connection area.

[0074] Each electrical connector 15 is associated with at least one electrical connection zone 130. The mechanical and electrical coupling interface between the electrical connector 15 and the electrical connection zone 130 depends of course on the shape and dimensions of the connection zone and those of the electrical connector 15.

[0075] In particular, the electrical connector 15 comprises: - an electrical coupling portion 152 forming an electrical interface with the electrical connection area 130 of the active film 10 to which it is associated, and more specifically with the electrically conductive layer 12 located in the associated electrical connection area 130 of the active film 10. The electrical coupling portion 152 is that which is connected to the electrically conductive layer 12 of the electrical connection area 130 to which the electrical connector 15 is associated, via the adhesive 14; and - a conduction portion 151 which extends projecting from the electrical coupling portion 152 and which is intended to be electrically coupled with a power supply unit to which the device 1 is intended to be connected. The conduction portion 151 extends in line with the electrical coupling portion 152, beyond the active film 10.The conduction part 151 and the electrical coupling part 152 each include electrical conductors which form electrical conduction lines through the electrical connector 15.

[0076] With reference to FIGURES 1 to 5, the electrical coupling part 152 of the electrical connector 15 is fixed to the electrically conductive layer 12 of the associated electrical connection area 130 of the active film 10, by means of the adhesive 14 which is applied to the electrical connection area 130.

[0077] Optionally, the electrical coupling portion 152 of the electrical connector 15 extends over the entire surface of the electrical connection area 130, as seen in the figure. In particular, as seen on the left of the figure, a lateral flank 153 of the electrical connector 15 is located against or in the immediate vicinity of a lateral side 133 of the electrical connection area 130 and / or a lateral edge 132 of the active film 10. Conversely, as seen on the right of the figure, a first lateral flank 153 of the electrical connector 15 is located against or in the immediate vicinity of a first lateral side 133 of the electrical connection area 130 and / or a first lateral edge 132 of the active film 10; while a second lateral flank 153 of the electrical connector 15 is located at a distance from a second lateral edge 132 of the active film 10, so that the electrical connector 15 and the associated electrical connection area 130 are eccentric with respect to the median longitudinal axis X of the device 1.In addition, the corresponding electrical connection area 130 extends over only part of the width of the active film 10, one lateral side 133 of the connection area being located at a distance from the lateral edge 132 of said active film 10.

[0078] In both cases, the electrical coupling part 152 of the electrical connector 15 overlaps completely with the electrical connection area 130, thus preventing the electrically conductive layer 12 from remaining in contact with the ambient air.

[0079] Alternatively, as seen in the embodiment examples illustrated in FIGURES 3 and 4, the electrical coupling portion 152 of the electrical connector 15 extends only over a portion of the associated electrical connection area 130. Indeed, if the electrical connection area 130 extends from and between the two lateral edges 132 of the active film 10, with the lateral sides 133 of the electrical connection area 130 coinciding with or located in close proximity to the lateral edges 132 of the active film 10, the electrical coupling portion 152 of the associated electrical connector 15 has reduced dimensions, such that the lateral sides 153 of the electrical connector 15 extend at a distance from the lateral sides 133 of the associated electrical connection area 130. This advantageous configuration simplifies the mounting of the electrical connector 15 on the active film 10, by providing a non-zero lateral clearance dY between the lateral side 153 and the lateral side 133.

[0080] Relative to the longitudinal axis X, a longitudinal flank 154 of the electrical connector 15 can be positioned against or coincide with a longitudinal side 134 of the electrical connection zone 130, in order to maximize the overlap of the electrically conductive layer 12 of the electrical connection zone 130 by the electrical coupling portion 152 of the electrical conductor. In this case, a longitudinal gap dX between the longitudinal flank 154 and the longitudinal side 134 is reduced, or even eliminated.

[0081] Alternatively, in order to facilitate the coupling of the electrical connector 15 to the electrical connection area 130, it is possible to provide a more extensive electrical connection area 130 along the longitudinal axis X, so that there is an extended and non-zero longitudinal clearance dX between the longitudinal flank 154 of the electrical connector 15 and the longitudinal side 134 of the associated electrical connection area 130.

[0082] Finally, the shape and / or type of electrical connector 15 associated with each at least one electrical connection zone 130 may vary in the context of the present invention. In particular: – the electrical connector 15 may be of the flexible type, such as a connection ribbon cable for example, or rigid, such as a connection strip or a busbar for example; and / or – the electrical coupling portion 152 may have a width, measured along the transverse axis Y, identical to that of the conduction portion 151, as illustrated in the example; or – the electrical coupling portion 152 may have a width, measured along the transverse axis Y, greater than that of the conduction portion 151, as illustrated in the example.In this case, the electrical connector 15 has a "T" or "Y" profile: the conduction part 151 extends mainly along the longitudinal axis X, while the electrical coupling part 152 extends mainly along the transverse axis Y. In this configuration, the electrical conductors that form the electrical connector 15, and which extend along the longitudinal axis X in the schematic representation of the FIGURES, are dispersed along the transverse axis Y, at the level of the electrical coupling part 152, in order to increase the contact area between said electrical coupling part 152 and the electrically conductive layer 12 of the associated electrical connection zone 130.

[0083] In summary, the invention relates to a device 1 for a motor vehicle, the device 1 comprising an active liquid crystal film 10 which has an active liquid crystal layer 11 covered on both sides, relative to a stacking direction of the layers 11, 12, 13, by an electrically conductive layer 12, each electrically conductive layer 12 being covered, only at the level of an active part of the active film 10, by an electrically insulating protective layer 13, the active film 10 having, at a longitudinal end 131, an electrical connection zone 130 located outside the active part. At the electrical connection zone 130, the electrically conductive layer 12 of the active film 10 is not covered by the protective layer 13.In addition, the device 1 includes an electrical connector 15 associated with the electrical connection area 130, the electrical connector 15 being mechanically and electrically coupled to the electrically conductive layer 12 of said electrical connection area 130 by means of an electrically conductive adhesive 14.

[0084] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the various features, forms, variants, and embodiments of the invention can be combined with one another in various ways, provided they are not incompatible or mutually exclusive. Specifically, all the variants and embodiments described above are combinable.

Claims

Device (1) for a light module of a motor vehicle, the device (1) comprising: - an active liquid crystal film (10), the active film (10) extending along a longitudinal axis (X) in the form of a multilayer strip stacked one on top of the other in a stacking direction, the multilayer strip comprising an active liquid crystal layer (11), the active layer (11) being covered by at least one electrically conductive layer (12), each at least one electrically conductive layer (12) being at least partially covered by an electrically insulating protective layer (13), the active film (10) comprising, at at least one longitudinal end (131) of the multilayer strip, at least one electrical connection zone (130) at which the at least one electrically conductive layer (12) is not covered by the protective layer (13);- at least one electrical connector (15) associated with at least one electrical connection zone (130), each at least one electrical connector (15) comprising at least one electrical conductor, the at least one electrical connector (15) extending across the associated electrical connection zone (130) of the active film (10), said at least one electrical connector (15) being mechanically and electrically coupled to said electrically conductive layer (12) of said corresponding at least one electrical connection zone (130) by means of an electrically conductive adhesive (14). Device (1) according to the preceding claim, wherein the electrically conductive layer (12) is optically transparent to visible light rays. Device (1) according to any one of the preceding claims, wherein at least one electrical connection zone (130) extends from at least one longitudinal end (131) of the active film (10) and along a length of at least 3 mm relative to the longitudinal axis (X) of the active film (10). Device (1) according to any one of the preceding claims, wherein, relative to a transverse axis (Y) of the active film (10), taken perpendicular to the longitudinal axis (X) and perpendicular to the stacking direction, at least one electrical connection zone (130) extends from one lateral side (133) to the other of the active film (10), or at least one electrical connection zone (130) extends at the level of a median portion located between the two lateral sides (133) and without reaching them. Device (1) according to any one of the preceding claims, wherein at least one electrical connector (15) comprises: - an electrical coupling part (152) forming an electrical interface with the electrical connection area (130) of the active film (10) to which it is associated, and more particularly with the electrically conductive layer (12) located in the associated electrical connection area (130) of the active film (10), and; - a conduction part (151) which extends projecting from the electrical coupling part (152) and which is intended to be electrically coupled with a power supply device of the device (1) and intended to provide electrical energy to said device (1). Device (1) according to the preceding claim, wherein at least one electrical connector (15) comprises several electrical conductors, the electrical coupling portion (152) and the conduction portion (151) together forming a "T" or "Y" profile, each electrical conductor forming the conduction portion (151) being distributed along the electrical coupling portion (152), such that a center distance between two adjacent electrical conductors, taken at the level of the conduction portion (151), is less than the center distance between said two adjacent electrical conductors, taken at the level of the electrical coupling portion (152). Device (1) according to claim 6, wherein at least one electrical connector (15) covers the entirety of the electrical connection area (130) to which it is associated, so that the electrically conductive layer (12) of the active film (10) is, at the level of said electrical connection area (130), entirely covered by at least one electrical connector (15). Device (1) according to claim 6, wherein at least one electrical connector (15) partially covers the electrical connection area (130) to which it is associated, such that there is a non-zero space between an edge of at least one electrical connector (15) and an edge of the corresponding electrical connection area (130). Device (1) according to the preceding claim, wherein the non-zero space is less than 5 mm, preferably between 1 mm and 2 mm. Device (1) according to any one of claims 1 to 9, wherein the adhesive (14) comprises an electrically conductive glue layer (14B) extending between at least one electrical connector (15) and the associated electrical connection area (130), and in particular the electrically conductive layer (12) of the active film (10). Device (1) according to the preceding claim, wherein the electrically conductive glue is of the type of a reticular glue. Device (1) according to any one of claims 1 to 9, wherein the adhesive (14) comprises an adhesive thermoplastic strip (14A) covering all of at least one electrical connector (15) and sticking it to the associated electrical connection area (130), and in particular to the electrically conductive layer (12) of the active film (10). Light module for motor vehicle, the light module comprising a device (1) according to any one of the preceding claims and a light source configured to generate light beams in the direction of the device (1) such that said beams pass through said liquid crystal active film (10) in the stacking direction.

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