Thin, flexible and luminous electroluminescent film having a metallized external appearance

Abstract

The invention relates to a flexible electroluminescent film (1) successively comprising: - a flexible carrier layer (2); - a first flexible electrode layer (3) made of conductive material; - a flexible electrically insulating layer (4) made of dielectric material; a flexible electroluminescent layer (5), comprising a phosphor layer (6) having a refractive index nlum; - a transparent second flexible electrode layer (8) made of conductive material having a refractive index n lum; - a flexible and semi-transparent metallized layer (9) comprising a material chosen from metalloids, poor metals, noble metals and transition metals, and from mixtures thereof and oxides thereof; and - a flexible and transparent protective layer (10). The electroluminescent layer (5) further comprises at least one element (7) for matching refractive index having a refractive index nng such that nlum > nng > n elec.

Description

DESCRIPTION TITLE: Thin, flexible, luminous electroluminescent film with a metallic external appearance TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of electroluminescent films which are both very flexible and very bright when powered by alternating electric current.

[0002] The present invention relates to such an electroluminescent film further having a metallized external appearance when not electrically excited. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Particularly in the automotive sector, the current trend is to decorate the interior and / or exterior of vehicles and to integrate signaling elements. Among these decorations and signaling elements, the most popular are those that are illuminated, especially because they remain visible even at night.

[0004] These decorations and signaling elements are sometimes based on light-emitting diodes (LEDs) or microLED arrays, and are generally in the form of light strips or wires, whose flexibility allows them to cover very diverse interior and body parts with concave and / or convex, sometimes complex, shapes.

[0005] However, these LED-based elements have many disadvantages.

[0006] Firstly, LEDs are expensive, so they are more commonly used for lighting than for decoration or signage.

[0007] Furthermore, LEDs tend to generate heat. Their use in large numbers therefore necessitates a cooling system, which adds bulk and thickness to the LED surfaces. Consequently, surfaces with a high LED density are neither thin nor flexible enough to conform to complex concave and / or convex shapes.

[0008] Finally, LEDs are not very energy efficient, with an efficiency of around 1%, and therefore consume a lot of electricity.

[0009] As a result, LED-based decorations are not always suitable for creating light decorations or illuminated signage elements.

[0010] Furthermore, these illuminated elements, when switched off, generally present an unsightly and uneven appearance. In the automotive field, this phenomenon not only makes these elements highly conspicuous compared to the rest of the vehicle, but also undermines the efforts made by automotive designers to create the most cohesive and aesthetically pleasing overall design possible.

[0011] Whether for decorative lighting or signaling elements, there is a need for light elements that are thin, flexible and adaptable so that they can cover complex concave and / or convex interior and body parts, while allowing great freedom in terms of patterns and dimensions, without being too power-hungry, and which can also present a uniform and aesthetic appearance, especially when switched off. SUMMARY OF THE INVENTION

[0012] The invention offers a solution to the problems mentioned above, by providing an electroluminescent film based on a top-emitting architecture comprising a stack of thin, flexible layers emitting a very strong light from the top of the structure, and in which a metallized layer is provided in the upper part of the film, which gives a metallized external appearance to the film when it is off, and which allows light to pass through when the electroluminescent film is on.

[0013] The thin, flexible and luminous electroluminescent film used in the invention is described in particular in detail in patent application FR2304675 in the name of the same applicant as the present application.

[0014] One aspect of the invention relates to a flexible electroluminescent film, characterized in that it comprises successively: a flexible support layer; a first flexible electrode layer made of conductive material; an electrically insulating flexible layer made of dielectric material; a flexible electroluminescent layer, comprising a phosphor layer having a refractive index rn U m; a second flexible and transparent electrode layer of conductive material having a refractive index Hélec J; a flexible and semi-transparent metallized layer comprising a material selected from metalloids, base metals, noble metals and transition metals, as well as from their mixtures and oxides; and a flexible and transparent protective layer.

[0015] Thanks to this invention, an electroluminescent film is provided that is advantageously thin, lightweight, flexible, very bright, and capable of providing all the colors of illumination in the visible spectrum. It can be supplied in sheet form in any size, is easy to cut and use, and advantageously has a uniform, metallic appearance when the electroluminescent layer is not excited; it is only visible when electrically excited and luminous. Furthermore, the power consumption of the electroluminescent film is more than three times lower than that of LEDs.

[0016] According to one aspect of the invention, the electroluminescent layer also comprises at least one refractive index matching element having a refractive index n ng such that nium > n ng> neiec. Thus, since light preferentially travels through the nearest material with a lower refractive index, the light emitted by the phosphor layer first passes through the material of the refractive index matching element, then through the second electrode layer to be emitted upwards through the film. As the refractive index of the matching element is intermediate between that of the adjacent layers with which it acts as an interface, its presence advantageously reduces any refraction and / or reflection of light from the phosphor layer towards the second electrode layer.

[0017] According to another aspect of the invention, the phosphor layer comprises zinc sulfide doped with at least one metal, including copper. Indeed, this type of Luminophore is advantageously very bright and can notably provide all the colors of lighting in the visible spectrum.

[0018] According to a further aspect of the invention, the metallized layer comprises a material selected from silicon, indium, aluminum, chromium, titanium, tantalum, zirconium, zinc, indium tin oxide, brass, copper, platinum, silicon dioxide, titanium dioxide, and their alloys. Indeed, these materials, in addition to exhibiting an attractive, particularly metallic, appearance when in the form of a thin layer, advantageously offer satisfactory transmittance for light from the electroluminescent layer.

[0019] According to one aspect of the invention, the metallized layer has a thickness of between 1 and 100 nm, preferably between 2 and 50 nm, and more preferably between 5 and 20 nm. Thus, in addition to allowing the film to be thin and flexible, this thickness advantageously enables the metallized layer to exhibit satisfactory transmittance for light from the electroluminescent layer. This transmittance is, for example, approximately 40% to 50%.

[0020] According to another aspect of the invention, the metallized layer is in the form of a flat and homogeneous layer. Thus, it can advantageously be deposited by simple and inexpensive deposition techniques.

[0021] According to a further aspect of the invention, the metallized layer is in the form of a grid, which improves the transmittance of the metallized layer to light from the electroluminescent layer. This transmittance is then multiplied by 1.5, and is, for example, approximately 60% to 75%.

[0022] According to one aspect of the invention, the film further comprises a flexible and transparent intermediate protective layer provided between the second electrode layer and the metallized layer. This intermediate protection serves, in particular, to protect the second electrode layer during the metallized layer deposition step and to prevent the metallized layer from receiving any of the electrical energy supplied to the electrode layers.

[0023] According to another aspect of the invention, the intermediate protective layer comprises one or more opaque parts. These opaque parts, for example printed, advantageously allow the creation of luminous patterns delimited by These offer numerous possibilities and aesthetic effects for the generated light patterns.

[0024] According to a further aspect of the invention, at least one protective layer comprises a transparent UV-blocking material, a UV-blocking additive, or a transparent UV-blocking coating. Thus, in addition to its role in protecting the environment, said protective layer also protects the film, in particular the phosphor layer, against the effects of ultraviolet radiation.

[0025] According to one aspect of the invention, at least one protective layer comprises a layer of transparent UV-resistant material selected from an acrylic resin, a mixture of high-density polyethylene and zinc oxide, polycarbonate, polyamide-imide, and poly(vinylidene fluoride). These materials exhibit highly effective UV protection and can therefore be supplied in a very thin layer that contributes to the film's flexibility and transparency.

[0026] According to another aspect of the invention, the support layer, the first electrode layer, the electrically insulating layer, and the electroluminescent layer are also transparent. Thus, all layers of the film are transparent, which advantageously allows for a completely transparent electroluminescent film.

[0027] Another aspect of the invention relates to a vehicle component, which is at least partially covered by a film as described above. Such a component can thus be decorated with luminous patterns offering all the freedom of form and size afforded by the invention.

[0028] According to one aspect of the invention, the vehicle component is a body part, a dashboard, a decorative element, a grille, a logo, or a headlight. Thanks to the invention, it is advantageously possible to incorporate lighting patterns on these components, which car manufacturers typically seek to make visually appealing.

[0029] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0030] The figures are presented for information purposes only and in no way limit the invention.

[0031] [Fig. 1] is an example of a schematic representation of an electroluminescent film according to a first variant of the invention where the electroluminescent layer comprises two successive layers.

[0032] [Fig. 2] is an example of a schematic representation of an electroluminescent film according to a second variant of the invention where the electroluminescent layer comprises refractive index matching elements embedded in a phosphor layer.

[0033] [Fig. 3] is a detailed view of the circled part in [Fig. 1].

[0034] [Fig. 4] is a detailed view of the circled part in [Fig. 2].

[0035] [Fig. 5] is an example of a schematic representation of an electroluminescent film according to a third variant of the invention where the electroluminescent layer comprises two successive layers and where an intermediate protective layer is provided between the second electrode layer and the metallized layer.

[0036] [Fig. 6] is an example of a schematic representation of an electroluminescent film according to a fourth variant of the invention where the electroluminescent layer includes refractive index matching elements embedded in a phosphor layer and where an intermediate protective layer is provided between the second electrode layer and the metallized layer.

[0037] The layer thicknesses shown in [Fig. 1] to [Fig. 4] are for illustrative purposes only and do not represent reality. DETAILED DESCRIPTION

[0038] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0039] By convention, in this application, the terms "lower" and "upper," and "inner" and "outer," are defined with respect to the position of the electroluminescent film as shown in the figures. Thus, an outer layer, such as the protective layer, is shown in the upper part of the film in the figures. while an internal layer, such as the support layer, is represented in the lower part of the film, even if the film can be used in a different orientation.

[0040] Within the scope of the invention, a material or layer of material is said to be flexible if the mechanical and electrical properties of the film remain unchanged even under a significant stress of 2.5% with a concave and convex radius of curvature of 0.5 mm. In other words, an electrode layer on the substrate layer can be considered flexible if, after a deformation of 2.5%, this deformation does not affect the variation in the electrical resistance of the electrode film deposited on the substrate layer. The deformation (flexibility) can be evaluated using the following equation:

[0041] Deformation = ( ts - tp - tf ) / 2 x rc, where: ts is the thickness of the support layer; tp is the total thickness of the working layers (luminescent layer + electrically insulating layers) tf is the total thickness of the electrode layers rc is the radius of curvature.

[0042] Finally, the term "transparent" refers to a material that is optically transparent, that is, one with a transmittance greater than 75% in the visible spectrum.

[0043] The film 1 according to the invention is a flexible electroluminescent film 1 comprising at least seven flexible and superimposed layers, where each layer is in contact with the adjacent layer(s), namely a support layer 2, a first electrode layer 3, an electrically insulating layer 4, an electroluminescent layer 5, a second electrode layer 8, a metallized layer 9 and a protective layer 10.

[0044] The film 1 according to the invention comprises a first, preferably lower, layer, which is a flexible support layer 2, onto which the other layers are deposited. This support layer 2 is preferably supplied in the form of a film roll. It has, for example, a thickness of between 0.5 and 2.0 mm, preferably between 0.8 and 1.5 mm, and more preferably equal to 1.1 mm.

[0045] The support layer 2 can be transparent, particularly when the entire film 1 is to be transparent. It can also be opaque, for example when film 1 is intended to be applied to an opaque surface.

[0046] In particular, where this layer is transparent, the support layer 2 is preferably made of PET (polyethylene terephthalate), Plasil (polymerized silicon monoxide-based siloxane), PMMA (polymethyl methacrylate), PCL (polycaprolactone), PC (polycarbonate), COP (cycloolefin polymer) or a mixture of at least two of these products.

[0047] The film 1 according to the invention comprises a second layer, deposited on the support layer 2, namely a first flexible electrode layer 3 made of conductive material.

[0048] This first electrode layer 3 is preferably supplied in the form of a nanonet (or nanomesh in English), a metal mesh (or electrode mesh in English) or a homogeneous flat layer.

[0049] A nanonet is a net-like nanostructure formed by nanowires in mutual contact, creating a mesh, whether these wires are interwoven, overlapping, welded, or a single piece. A nanowire is a thread-like nanostructure with a diameter on the nanoscale, for example, less than 100 nm, and a significantly greater length.

[0050] By wire mesh, we mean a net-like structure, made of interlaced, superimposed, welded or single-piece wires, these wires having a diameter on the order of a micron.

[0051] The unit patterns of the mesh of such a nanonet or metal lattice can, for example, be squares, rectangles, triangles, rhombuses, hexagons or any other shapes and combinations thereof.

[0052] By homogeneous flat layer, we mean a layer of material substantially flat, without significant inequalities in level, whose composition and structure are substantially the same at every point, and which extends over a surface suitable for forming an electrode of the desired surface area, for example substantially equal to the surface of the support layer 2 where we wish to form a luminescent film.

[0053] The first electrode layer 3, when supplied in the form of a nanonet or a metal mesh, preferentially comprises silver nanowires (or AgNWs for Ag nanowires) or copper nanowires (or CuNWs for Cu nanowires).

[0054] It should be noted that wide bandgap nanowires composed of gallium nitride (GaN) or zinc oxide (ZnO) are materials that can also be used for nanowires.

[0055] When supplied as a flat layer, the first electrode layer 3 preferentially comprises carbon nanotubes, graphene, a metal oxide-based material, a PEDOT [poly(3,4-ethylenedioxythiophene)]-based material, a PEDOT:PSS [poly(3,4-ethylenedioxythiophene) mixed with sodium polystyrene sulfonate]-based material, or a PEDOT:TOS [poly(3,4-ethylenedioxythiophene) mixed with tosylate]-based material. Such a flat layer is as homogeneous as possible and usually unstructured.

[0056] Metal oxide-based materials for the first electrode layer 3 preferentially include ITO (indium tin oxide), ZnO (zinc oxide), ZnO:Al (aluminum-doped zinc oxide), TiO2 (titanium dioxide) and SnO2:F (fluorine-doped tin dioxide, or FTO for Fluorine-doped Tin Oxide).

[0057] The first electrode layer 3 can be transparent or opaque.

[0058] The film 1 according to the invention comprises a third layer, deposited on the first electrode layer 3, namely a first electrically insulating flexible layer 4 made of dielectric material.

[0059] This electrically insulating layer 4 has, for example, a thickness between 1 and 50 pm. It preferably has a thickness between 5 and 30 pm, more preferably between 8 and 15 pm, for example approximately equal to 10 pm.

[0060] The dielectric material of the electrically insulating layer 4 preferably comprises an epoxy resin matrix loaded with alkaline earth metal titanate particles, which alkaline earth metal being selected from calcium titanate (CaTiOa), barium titanate (BaTiOa), strontium titanate (SrTiOa), mixed perovskites of the barium and strontium titanate type (Ba x Sr(i- X )TiO3, with 0 < x < 1 ) and a mixture of these products. Preferably x is such that 0 < x < 1 .

[0061] The electrically insulating layer 4 can be transparent or opaque.

[0062] The film 1 according to the invention comprises a fourth layer, deposited on the electrically insulating layer 4, namely a flexible electroluminescent layer 5.

[0063] This electroluminescent layer 5 comprises both a luminophore material capable of generating light, and a refractive index matching material capable of directing the light emitted by the luminophore material towards the following upper layers, namely the second electrode layer 8 and the protective layer 9.

[0064] Luminophore here refers to a material containing electroluminescent pigments that emit white or colored light after receiving energy supplied by an electric field.

[0065] Thus, the electroluminescent layer 5 comprises a phosphor layer 6 having a refractive index rn U m and at least one refractive index matching element 7 having a refractive index n ng so that nium > n ng > neiec where neiec is the refractive index of the second electrode layer 8.

[0066] Since the refractive index of the refractive index matching element 7 is intermediate between that of the adjacent layers for which it serves as an interface, its presence reduces the effects of refraction and / or reflection of light from the phosphor layer 6 towards the second electrode layer 8.

[0067] Laboratory tests have proven that adding the refractive index matching element 7 to a conventional electroluminescent film multiplies its luminance by a factor of between 1.8 and 2. Thus, for a film 1 according to the invention, for which the luminance is optimized, a luminance greater than 1600 cd / m² is obtained. 2 , which can even exceed 2000 cd / m 2 values ​​that have never been achieved to date for an electroluminescent film.

[0068] According to a first variant of the invention shown in [Fig. 1] and [Fig. 3] The electroluminescent layer 5 comprises two successive layers, namely a phosphor layer 6 located on the electrically insulating layer 4, and a refractive index matching element layer 7 located on the phosphor layer 6.

[0069] According to a second embodiment of the invention shown in [Fig. 2] and [Fig. 4], the electroluminescent layer 5 comprises a heterogeneous layer including refractive index matching elements 7 located on the electrically insulating layer 4 and embedded in a phosphor layer 6. According to this second embodiment of the invention, a layer of refractive index matching element 7 may also be located on said heterogeneous layer.

[0070] The phosphor layer 6 has a refractive index rn U m whose value is for example approximately equal to 4. In the context of the invention, each refractive index is measured by method A of the standard NF EN ISO 489 of March 2022.

[0071] Luminophore layer 6 comprises zinc sulfide doped with at least one metal including copper.

[0072] By metallic composition doped with a material, we mean here a metallic composition incorporating small quantities (generally on the order of ppm) of a material which is introduced into its matrix in order to modify its properties.

[0073] For example, the luminophore layer 6 comprises zinc sulfide, a mixture of zinc sulfide and cadmium sulfide, or a mixture of zinc sulfide, cadmium sulfide, zinc selenide, and cadmium selenide. Preferably, these metallic compositions are either doped with copper alone or doped with copper and at least one compound selected from the group consisting of yttrium aluminum garnet, manganese, aluminum, europium, and inorganic dyes.

[0074] The deposition of the phosphor layer 6 is preferably carried out by screen printing, by atomic thin film deposition (or ALD, for the English Atomic Layer Deposition) or by a sol-gel process.

[0075] Screen printing or ALD deposition is preferred in the case of the first variant of the invention, where the electroluminescent layer 5 comprises two successive layers, while sol-gel deposition is preferred in the case of the second variant of the invention, where the electroluminescent layer 5 comprises refractive index adaptation elements 7 embedded in a phosphor layer 6.

[0076] Screen printing deposition generally allows for the provision of a luminophore 6 layer with a thickness of, for example, between 25 and 30 pm, because the particles of the luminophore 6 layer usually have a diameter less than or equal to 29 pm.

[0077] In the case where the deposit of the luminophore layer 6 is carried out by screen printing, the electroluminescent pigments are preferentially bound in an epoxy resin matrix.

[0078] The refractive index 7 matching element is transparent and, when in the form of a layer, it is flexible.

[0079] The refractive index matching element 7 has the role of directing the light emitted towards the phosphor layer 6 towards the second electrode layer 8 located above it, so that a greater part of the light emitted by the phosphor layer 6 passes through the second electrode layer 8, for greater brightness of the film 1.

[0080] Thus, the refractive index matching element 7 has a refractive index n ngwhose value is chosen so as to be between that of the two adjacent layers, namely the phosphor layer 6 and the second electrode layer 8, so as to form an intermediate layer reducing the effects of refraction and / or reflection of light. The refractive index n ng the adaptation element of the refractive index is for example between 2 and 3.5.

[0081] The refractive index matching element 7 preferentially comprises nano-antennas 12, also known as light nanosensors, or nano-antennas in English

[0082] These nano-antennas 12 preferentially comprise nano-objects, preferably metallic, which promote the movement of light from the phosphor layer 6 to the second electrode layer 8, at a scale smaller than the wavelength, so that the refractive index matching element 7 is also very thin and transparent.

[0083] According to one embodiment of the invention, the nano-objects can be colloidal nanoparticles, preferably nano-cubes, as illustrated in [Fig. 3]. They can also be three-dimensional elements with round, oval, triangular, square, rectangular, rhombic, polygonal, etc. cross-sections or other polygonal three-dimensional elements, such as tetrahedra, octahedra, dodecahedra, icosahedra, etc.

[0084] A nanoparticle is a nano-object whose three dimensions are on the nanometric scale, that is to say a particle whose nominal diameter is less than about 100 nm.

[0085] Colloidal nanoparticles are preferentially based on silver, gold, platinum or a mixture thereof.

[0086] In the case of the second variant of the invention, where the electroluminescent layer 5 comprises refractive index matching elements 7 embedded in a phosphor layer 6, the nanoparticles are preferentially deposited on the electrically insulating layer 4 by a drop-deposition process, for example randomly, but in such a way that the nanoparticles are well dispersed, without aggregates and with the most homogeneous density possible on the phosphor layer 6.

[0087] In the case of the first embodiment of the invention, where the electroluminescent layer 5 comprises two successive layers, the colloidal nanoparticles are preferably embedded in a matrix, for example, polyvinylpyrrolidone (PVP), or coated with a layer of PVP. This matrix or PVP layer has, for example, a thickness of approximately 1 to 10 nm, preferably approximately 3 nm.

[0088] According to another variant of the invention, the nano-objects can be nanofibers, nanotubes, nanofilaments, nanowires, nanorods, nanorods as illustrated in [Fig. 4], or a mixture of these nano-objects.

[0089] Nanofibers, nanotubes, nanofilaments, nanorods and nanorods are nano-objects whose two similar external dimensions are on the nanometric scale, less than about 100 nm, and whose third dimension is significantly larger.

[0090] These nano-objects are preferably based on zinc oxide. They are grown for example by hydrothermal synthesis from a layer of ZnO seeds directly deposited on the phosphor layer 6 (first variant of the invention) or on the electrically insulating layer 4 (second variant of the invention).

[0091] These nano-objects are preferentially arranged in the form of a very dense network of vertically aligned nanowires (NWs), nanofibers, nanotubes, nanofilaments, nanorods and / or nanorods. They preferentially have a diameter between 30 and 50 nm and a length between 400 and 500 nm.

[0092] In the case of the second variant of the invention, where the electroluminescent layer 5 comprises refractive index matching elements 7 embedded in a phosphor layer 6, the nanoparticles and nano-objects can, for example, be deposited in the form of islands, i.e. in the form of small groups of nanoparticles and nano-objects isolated from each other, or in the form of lines, in particular parallel and / or intersecting to form a network.

[0093] The refractive index matching elements 7, whether embedded in the phosphor layer 6 or in the form of a separate layer, may have a very small height (or thickness in the case of a layer), in particular less than 1 pm.

[0094] Depending on its thickness, the luminophore layer 6 can be transparent, translucent or opaque.

[0095] The film 1 according to the invention comprises a fifth layer, deposited on the electroluminescent layer 5, namely a second flexible and transparent electrode layer 8 made of conductive material.

[0096] This second electrode layer 8 can have the same characteristics as the first electrode layer 3.

[0097] It has a refractive index neiec whose value is, for example, approximately equal to 1.5.

[0098] Within the same film 1 according to the invention, the first electrode layer 3 and the second electrode layer 8 may be identical, for example in their nature, composition, thickness and / or deposition process, but they may also be different. However, it is more practical and less expensive for the manufacture of film 1 if the first and second layers of electrode 3, 8 are identical.

[0099] The first and second electrode layers 3, 8 are intended to be connected to an alternating current source in order to form an electrostatic field between them, capable of exciting the phosphor layer 6 provided between these two layers 3, 8.

[0100] The film 1 according to the invention comprises a sixth layer, deposited on the second electrode layer 8, namely a flexible and semi-transparent metallized layer 9.

[0101] This metallized layer 9 comprises at least one material that preferably has a metallic appearance. This material is chosen from among the metalloids (B, Al, Si, Ge, As, Sb, Te, Po, Se, and At), the base metals (Ga, In, Sn, Tl, Pb, and Bi), the noble metals (Au, Ag, Ru, Rh, PD, Os, Ir, and Pt), and the transition metals (Ag, Cr, Co, Cu, Fe, Ir, Mn, Hg, Ni, Au, Os, Pt, Re, Sc, Ta, Ti, W, V, and Zn). The metallized layer 9 may also comprise a material chosen from among the oxides of the aforementioned materials. Finally, the metallized layer 9 may also comprise a material chosen from among the various possible mixtures of the aforementioned materials and / or their oxides.

[0102] Preferably, the metallized layer 9 comprises a material selected from silicon, indium, aluminium, chromium, titanium, tantalum, agent, zirconium, zinc, indium tin oxide, brass, copper, platinum, silicon dioxide, titanium dioxide and their alloy.

[0103] These materials are particularly preferred because their reflected color allows for the creation of a decorative film and an aesthetic effect that helps to obscure or camouflage the lighting module, which illuminates in a backlit configuration.

[0104] The metallized layer 9 preferentially has a thickness between 1 and 100 nm, preferably between 2 and 50 nm and more preferably between 5 and 20 nm.

[0105] The metallized layer 9 can be in the form of a flat and homogeneous layer, that is to say in the form of a single piece of material, without holes, and preferably as uniform as possible.

[0106] According to this embodiment of the invention, the metallized layer 9 can be deposited by thermal evaporation, a thin-film deposition method most often used for applications involving electrical contacts, by depositing simple metals such as silver or aluminum. Thermal evaporation allows the deposition of both metals and non-metals, including aluminum, chromium, gold, indium, and many others.

[0107] The metallized layer 9 can also be in the form of a grid, that is to say in the form of a layer of material distributed in lines or bands which cross and / or overlap so as to form a mesh, the unit patterns of which can for example be squares, rectangles, triangles, diamonds, circles, hexagons or any other shapes and combinations thereof to promote the transmittance of the film 1.

[0108] According to this embodiment of the invention, the metallized layer 9 can be deposited by one of the following techniques:

[0109] Physical vapor deposition (PVD), a technique similar to evaporation or sputtering, involves the physical deposition of material atoms onto a substrate. In this process, the metallic material is vaporized in a vacuum chamber and then condensed onto the substrate, forming a thin metallic film. By controlling parameters such as the deposition angle and speed, it is possible to deposit metallic mesh structures with a high degree of precision. [001 10] Chemical vapor deposition (CVD) involves the chemical reaction of precursor gases to deposit materials onto a substrate. In the case of metallic materials, suitable metal-organic precursors are used, which decompose under heat to form metallic deposits. By controlling the reaction conditions, such as temperature and gas composition, it is possible to selectively deposit metallic materials in the form of a mesh. [001 1 1 ] PVD and CVD methods are widely used in various fields, including microelectronics, photonics and flexible electronics, where metallic meshes find applications in areas such as transparent conductive films and sensors. [001 12] Finally, the film 1 according to the invention comprises a seventh layer, preferably upper, deposited on the second electrode layer 8, namely a flexible and transparent protective layer 10. [001 13] This protective layer 10 has, for example, a thickness between 0.5 and 2.0 mm, preferably between 0.8 and 1.5 mm and more preferably equal to 1.1 mm. [001 14] It is preferably filed by printing. [001 15] The protective layer 10 is preferably made of PET (polyethylene terephthalate), Plasil (polymerized silicon monoxide siloxane), PMMA (polymethyl methacrylate), PCL (polycaprolactone), PC (polycarbonate), COP (cycloolefin polymer) or a mixture of at least two of these products. [001 16] The protective layer 10 preferably comprises a transparent anti-UV material, an anti-UV additive or a transparent anti-UV coating in order to protect the film 1 from the harmful effects of ultraviolet radiation. [001 17] Indeed, UV protection can be embedded in the mass of the material constituting the protective layer 10, or be in the form of a coating deposited on the lower and / or upper layer of said protective layer 10. [001 18] Similarly, the constituent material of the protective layer 10 may naturally have an anti-UV effect, or be modified so as to exhibit such an effect without negatively affecting its flexibility and transparency in a significant way. [001 19] Thus, the protective layer 10 comprises, for example, a layer of transparent anti-UV material chosen from an acrylic resin, a mixture of high-density polyethylene and zinc oxide, polycarbonate, polyamide-imide and poly(vinylidene fluoride).

[0120] The following materials are known to have anti-UV action: Plasil anti-UV, PC, PCL, PMMA, PET and COP.

[0121] According to a variant of the invention illustrated in [Fig. 5] and [Fig. 6], the film 1 comprises a flexible and transparent intermediate protective layer 11 provided between the second electrode layer 8 and the metallized layer 9.

[0122] This intermediate protective layer 11 can have the same characteristics as the protective layer 10.

[0123] Within a single film 1 according to the invention, the protective layer 10 and the intermediate protective layer 11 may be identical, for example in their nature, composition, thickness and / or deposition process, but they may also be different. However, it is more practical and less costly for the manufacture of the film 1 if these layers are identical.

[0124] The intermediate protective layer 11 may not be transparent over its entire surface and may include one or more opaque sections separating transparent areas. The opaque sections may have various patterns and shapes. Here, "opaque" refers to a material that does not allow visible light from the electroluminescent layer 5 to pass through.

[0125] Thus, when the phosphor layer 6 is excited and becomes luminous, the transparent parts of the intermediate protective layer 11 allow light to pass through and form luminous patterns on the outside whose shape corresponds to those of the transparent parts.

[0126] The transparent parts can be any shape. For example, they can be in the form of dots, circles, ovals, chevrons, oblongs, squares, rectangles, triangles, stars, crosses, diamonds, polygons, honeycombs, alphanumeric characters, or be in the form of a combination of at least two of these patterns.

[0127] To create an organized aesthetic effect, the transparent sections can be arranged in rows, with the patterns then either aligned in columns or staggered. The transparent sections are preferably distributed uniformly across the surface of the intermediate protective layer 11. They can also be distributed progressively, with the surface of the intermediate protective layer 11 gradually covered by more and more transparent sections or, conversely, by fewer and fewer transparent sections.

[0128] Opaque parts can, for example, be made of an opaque polymer material, and deposited, for example, by screen printing, physical vapor deposition (PVD) or chemical vapor deposition (CVD).

[0129] The film 1 according to the invention is preferably intended for decorating the interior or exterior of a vehicle, but its applications are countless. For example, it can be used indoors as well as outdoors, to decorate a building, furniture, accessories, architectural elements, clothing, etc.

[0130] Thus, the invention also relates to a vehicle component at least partially covered by a film 1 according to the invention, this component being for example a body part, a dashboard, a decorative part, a grille, a logo, a lens or any other part of a vehicle.

[0131] Finally, the invention also relates to a method for manufacturing a film 1 according to the invention comprising the following successive steps: supplying a flexible support layer 2; deposition of a first flexible electrode layer 3 of conductive material on the flexible support layer 2; deposition of a flexible electrically insulating layer 4 of dielectric material on the first electrode layer 3; deposition of a flexible electroluminescent layer 5 comprising a phosphor layer 6 on the electrically insulating layer 4; deposition of a second flexible and transparent electrode layer 8 of conductive material on the electroluminescent layer 5; deposition of a flexible and semi-transparent metallized layer 9 on the second electrode layer 8, this metallized layer 9 comprising a material selected from metalloids, base metals, noble metals and transition metals, as well as from their mixtures and oxides;and application of a flexible and transparent protective layer 10 on the metallized layer 9.;

[0132] According to a variant of the invention, the process for manufacturing a film 1 according to the invention comprises the following successive steps: supplying a flexible support layer 2; deposition of a first flexible electrode layer 3 made of conductive material on the flexible support layer 2; deposition of a flexible electrically insulating layer 4 made of dielectric material on the first electrode layer 3; - deposition of a flexible electroluminescent layer 5 comprising a phosphor layer 6 on the electrically insulating layer 4; deposition of a second flexible and transparent electrode layer 8 made of conductive material on the electroluminescent layer 5; deposition of a flexible and transparent intermediate protective layer 11 on the second electrode layer 8; deposition of a flexible and semi-transparent metallized layer 9 on the intermediate protective layer 11, this metallized layer 9 comprising a material selected from metalloids, base metals, noble metals and transition metals, as well as from their mixtures and oxides;and application of a flexible and transparent protective layer 10 on the second metallized layer 9.;

Claims

CLAIMS

1. Flexible electroluminescent film (1), characterized in that it successively comprises: - a flexible support layer (2); - a first flexible electrode layer (3) made of conductive material; - a flexible electrically insulating layer (4) made of dielectric material; - a flexible electroluminescent layer (5), comprising a phosphor layer (6) having a refractive index rn U m ; - a second flexible and transparent electrode layer (8) made of conductive material having a refractive index Hélec J - a flexible and semi-transparent metallized layer (9) comprising a material chosen from metalloids, poor metals, noble metals and transition metals, as well as from their mixtures and their oxides; and - a flexible and transparent protective layer (10).

2. Film (1) according to claim 1, characterized in that the electroluminescent layer (5) further comprises at least one refractive index matching element (7) having a refractive index n ng such that nium > n ng > néiec.

3. Film (1) according to claim 1 or 2, characterized in that the phosphor layer (6) comprises zinc sulfide doped with at least one metal including copper.

4. Film (1) according to any one of the preceding claims, characterized in that the metallized layer (9) comprises a material chosen from silicon, indium, aluminum, chromium, titanium, tantalum, agent, zirconium, zinc, indium-tin oxide, brass, copper, platinum, silicon dioxide, titanium dioxide and their alloy.

5. Film (1) according to any one of the preceding claims, characterized in that the metallized layer (9) has a thickness of between 1 and 100 nm, preferably between 2 and 50 nm and more preferably between 5 and 20 nm.

6. Film (1) according to any one of the preceding claims, characterized in that the metallized layer (9) is in the form of a flat and homogeneous layer.

7. Film (1) according to any one of claims 1 to 5, characterized in that the metallized layer (9) is in the form of a grid.

8. Film (1) according to any one of the preceding claims, characterized in that it further comprises a flexible and transparent intermediate protective layer (11) provided between the second electrode layer (8) and the metallized layer (9).

9. Film (1) according to the preceding claim, characterized in that the intermediate protective layer (11) comprises one or more opaque parts.

10. Film (1) according to any one of the preceding claims, characterized in that at least one protective layer (10, 11) comprises a transparent anti-UV material, an anti-UV additive or a transparent anti-UV coating. [Claim 1 1 ] Film (1 ) according to any one of the preceding claims, characterized in that at least one protective layer (10, 1 1 ) comprises a layer of transparent anti-UV material chosen from an acrylic resin, a mixture of high density polyethylene and zinc oxide, polycarbonate, polyamide-imide and poly(vinylidene fluoride).

12. Film (1) according to any one of the preceding claims, characterized in that the support layer (2), the first electrode layer (3), the electrically insulating layer (4) and the electroluminescent layer (5) are transparent.

13. Vehicle element, characterized in that it is at least partially covered by a film (1) according to any one of the preceding claims.

14. Vehicle element according to the preceding claim, characterized in that said element is a bodywork part, a dashboard, a decorative part, a grille, a logo or an optical element.

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