Electrochromic multilayer electroactive reflective modules and related systems and methods of production

Abstract

The invention relates to a multilayer electroactive reflective module (1) for an automotive part, comprising a substrate (10); a multilayer stack (18) arranged on the substrate (10) and configured to reflect a reflected light beam (2 ') having a determined wavelength dependent on a potential difference applied to the stack (18); a first electrode (12) and a second electrode (13) configured to apply a potential difference, the multilayer stack comprising a metal mirror (14) and an electrochromic layer (15) having a nano-thickness (d15), the electrochromic layer comprising at least one solid polymer electrolyte (16) and at least one electrochromic molecule (17) so as to vary the absorption of the electrochromic layer (15) based on the potential difference applied to the stack (18).

Description

Technical Field

[0001] This invention relates to the field of electroactive reflective multilayer modules. They can be particularly advantageously used in the fields of motor vehicle cladding or signal transmission, especially for front-end components of vehicles or the interior compartments of such vehicles. Background Technology

[0002] A common practice is to incorporate patterns or visual elements into vehicle parts for decorative or signal transmission purposes. For this purpose, light sources are typically used to display these patterns both during the day and at night. To limit the power consumption of this type of module, a more economical solution that utilizes ambient light, at least during the day, is expected.

[0003] For this purpose, electroactive reflective multilayer modules exist that are configured to reflect a portion of the visible spectrum and thus exhibit a specific color. In particular, modules utilizing the Fabry-Pérot cavity effect are known. In a Fabry-Pérot cavity, when light is confined within a nanocavity defined by two substantially parallel surfaces, a reflected color known as "structural color" appears. These modules comprise a substrate on which a stack is formed, comprising at least one mirror layer and a Fabry-Pérot absorber layer, such as a conductive polymer layer. In existing solutions, the thickness of the absorber layer determines the wavelength of the reflected light beam that will be emitted from the polymer layer through an interference phenomenon. These specific wavelengths correspond to colors in the visible spectrum and reach the observer's eye. Therefore, the observer has the impression that the material layer has changed color.

[0004] To allow for adjustment of the thickness of the conductive polymer layer, a module incorporating a liquid electrolyte tank exists. The thickness of the conductive polymer layer can be adjusted via a reversible redox process in the presence of an ion source when subjected to a potential difference.

[0005] In practice, these systems are limited. The architecture and multi-layered structure of these systems are complex. Furthermore, the use of liquid electrolyte tanks can lead to leaks and connection problems. This hinders the integration of these systems into applications such as automobiles.

[0006] Therefore, one object of the present invention is to provide a solution that improves upon existing solutions by providing an electroactive reflective multilayer module, and in particular, makes it compatible with applications in automotive parts.

[0007] Other objects, features, and advantages of the invention will become apparent from the following description and accompanying drawings. It should be understood that other advantages can be combined. Summary of the Invention

[0008] To achieve this objective, according to the first aspect, a multilayer electroactive reflective module is provided, preferably for use in automotive parts, the module comprising: -First substrate, - A multilayer stack disposed on a first substrate and configured to receive an incident light beam and reflect a reflected light beam having a defined wavelength depending on a potential difference applied to the stack, the multilayer stack including at least one layer forming a metallic mirror. - A first electrode and a second electrode, which are electrically connected on both sides of a multilayer stack and are configured to apply the potential difference.

[0009] Advantageously, the multilayer stack includes an electrochromic layer having a nanometer thickness and covered with a metallic mirror, the electrochromic layer comprising: -At least one solid polymer electrolyte, - At least one electrochromic molecule different from the at least one solid polymer electrolyte in order to change the absorption of the electrochromic layer according to the potential difference applied to the stack.

[0010] In this document, the proposed reflective module may also be referred to as a multilayer electroactive reflective unit, wherein the first substrate is covered by a multilayer stack. The term "module" is used to specify a modular element that is independent and self-sufficient to achieve the desired effect, in particular structural reflection (i.e., the return of a specific wavelength generated by the structure of the modular element based on a stimulus applied to the element).

[0011] Because the electrochromic layer is nanometer-thick, it forms a Fabry-Perot cavity. The properties of this layer are modulated by electrochromic molecules that, depending on the applied potential difference, exhibit a redox form with absorption peaks. Therefore, the electrochromic molecules alter the absorption of the electrochromic layer according to wavelength, and more specifically in the visible light range. Thus, the electrical stimulation caused by the potential difference changes the refractive index of the material. More specifically, the absorption coefficient varies based on the applied potential difference. The unabsorbed wavelengths generated by the constructive interference of the Fabry-Perot layer form a beam of light reflected from the mirror. Therefore, the reflection module allows for the alteration of the length of the reflected beam, and thus the change in color perceived by the user. This solution differs from existing solutions where the thickness of the Fabry-Perot layer is varied to modulate the wavelength of the beam. Therefore, the mechanical stress caused by this thickness variation can be eliminated. A wide variety of colors can be obtained depending on the one or more electrochromic molecules used.

[0012] An electrochromic layer comprising a solid polymer electrolyte allows for the supply of necessary ions to the electrochromic molecules during the redox reaction induced by a potential difference. Therefore, the redox form of the electrochromic molecules can be altered to modulate the reflected wavelength. Because the electrochemical layer comprises both a solid polymer electrolyte and electrochromic molecules, the reflection module is simplified and thus easier to manufacture. This module differs from solutions that can provide multilayer components comprising both an electrochromic layer and an electrolyte layer. The solid polymer electrolyte also improves the stability of the chemicals involved in the redox process of the electrochromic molecules, thereby improving the reversibility of color changes and broadening the electrochromic color palette.

[0013] Here, "molecule" means an entity capable of existing in a free state, regardless of the stimulus applied to the multilayer stack. According to an exemplary embodiment, the electrochromic molecule may be specified as a monomer or monomer molecule composed of low molecular weight molecules as defined. The monomer molecules remain separate and do not polymerize in the presence of a voltage applied to the multilayer stack.

[0014] The stacked structure is in a solid or semi-solid form, which avoids leakage and reduces the size and weight of the reflective module compared to existing solutions using liquid electrolytes. Solid polymer electrolytes also exhibit improved thermal stability. Furthermore, solid polymer electrolytes exhibit improved flexibility. Therefore, the reflective module can possess both flexibility, making it easier to integrate into automotive applications (e.g., integration onto curved surfaces), and good mechanical strength.

[0015] Using solid polymer electrolytes, and especially solid polymer electrolytes in the form of gels or semi-solid materials, avoids some of the assembly difficulties associated with using liquid electrolytes. Liquid electrolytes are typically introduced into pre-assembled functional battery cells via surface capillary action, typically with openings positioned at opposite corners. Once the liquid electrolyte comes into contact with one of the openings, it rises through the cavity of the battery cell. However, as filling progresses, the rising becomes more difficult due to the increased potential energy of the electrolyte, limiting the size of the device and increasing the risk of air bubbles.

[0016] Furthermore, solid polymer electrolytes, especially those in the form of gels or semi-solid materials, facilitate the assembly of the electrochromic layer with the substrate. This makes electronic contact between the electrode substrate and the electrochromic layer easier, minimizing the risk of colorless regions appearing in the electrochromic layer even when a potential difference is applied. This is particularly advantageous in the case of large-area reflective modules.

[0017] Therefore, solid polymer electrolytes, and especially solid polymer electrolytes in the form of gels or semi-solid materials, are easier to handle than liquid electrolytes and provide better interaction with the substrate and (where applicable) the electrodes, particularly due to their viscosity and / or adhesion. This makes it easier to manufacture reflective modules on an industrial scale.

[0018] The architecture of the reflective module is also simplified. A single electrochromic layer may be sufficient, without requiring the addition of other layers, particularly layers of conductive polymer and counter electrodes, as would be the case for modules with Fabry-Perot layers whose thickness varies with the applied potential difference. Thus, the stack can be formed from only at least one metallic mirror and one or more electrochromic layers.

[0019] Furthermore, reflective modules offer reduced energy consumption. This is because a small potential difference of approximately ±2 V is typically sufficient to modulate the redox form of electrochromic molecules and alter the reflected color, particularly within the visible light range. This makes reflective modules more versatile. Consequently, they are particularly well-suited for automotive applications.

[0020] According to a second aspect, the present invention relates to an electroactive reflective system, preferably for use in automotive parts, comprising at least one reflective module as described in the preceding aspect. The system incorporates the effects and advantages of the reflective module and is therefore particularly suitable for automotive applications.

[0021] According to a third aspect, the present invention relates to a method for producing a reflective module according to a first aspect or a reflective system according to a second aspect, comprising: -Supply a first substrate including a first electrode, and supply a second electrode, - Deposit at least one layer forming a metallic mirror on the first substrate. - Deposit an electrochromic layer on one of the metal mirror and the second electrode. - The first substrate and the second electrode are assembled by means of an electrochromic layer and another one from a metal mirror and a second electrode, such that the multilayer stack is connected to the first electrode and the second electrode on both sides.

[0022] The reflective module is therefore manufactured as two sub-modules that can be more easily assembled. This allows for the parallel production of these two sub-modules, thereby reducing production time. Furthermore, the formation of the electrochromic layer is therefore independent of the formation of the layer covering it. This avoids the risk of degradation of the electrochromic layer due to the deposition of another layer thereon. According to one example, the method includes supplying a second substrate, the second substrate including a second electrode, the method such that: - The method further includes assembling a first substrate and a second substrate to form a multilayer stack by means of the electrochromic layer and the other of the metal mirror and the second electrode after the electrochromic layer has been deposited on one of the metal mirror and the second electrode.

[0023] According to one example, an electrochromic layer is deposited on a metal mirror, and a first substrate and a second electrode are assembled through the electrochromic layer and the second electrode.

[0024] A fourth aspect of the invention relates to a motor vehicle part comprising a reflective module according to the first aspect or a reflective system according to the second aspect. Attached Figure Description

[0025] The objectives, features, and advantages of the present invention will become more apparent from the detailed description of embodiments of the invention illustrated in the following figures, in which: [ Figure 1 ] Figure 1 A reflection module according to an exemplary embodiment is shown.

[0026] [ Figure 2 ] Figure 2 This is a diagram illustrating the changes in the redox forms of electrochromic molecules in an electrochromic layer during a redox reaction, according to an exemplary embodiment.

[0027] [ Figure 3 ] Figure 3 An automotive part including a reflection system is shown according to an exemplary embodiment.

[0028] [ Figure 4 ] Figure 4 A reflection module according to another exemplary embodiment is shown.

[0029] [ Figure 5 ] Figure 5 A waveguide-included reflection system is shown according to an exemplary embodiment.

[0030] [ Figure 6 ] Figures 6 to 10 The steps of a method for a production module according to several exemplary embodiments are shown.

[0031] [ Figure 7A ]、[ Figure 7B ]、[ Figure 7C ]、[ Figure 8A ]、[ Figure 8B ]、[ Figure 9 ]and[ Figure 10 ] These accompanying drawings are given by way of example and do not limit the invention. They are schematic block diagrams intended to facilitate a better understanding of the invention and are not necessarily to scale for actual applications. In particular, the relative dimensions of the substrate and layers, and the thickness of the layer or substrate relative to its other dimensions, do not necessarily represent actual conditions. Detailed Implementation

[0032] Before we begin to discuss the embodiments of the present invention in detail, the following will describe optional features that may be used in combination or alternatively.

[0033] As an example, a solid polymer electrolyte comprises: Ionic gels comprising a polymer matrix and an ionic liquid, and / or Polymer ionic liquids.

[0034] Therefore, solid polymer electrolytes possess good ionic conductivity and allow for improved charge transfer in the redox reactions of electrochromic molecules. This makes it easier to change the wavelength of the reflected beam. Ion gels and solid polymer electrolytes based on one or more polymer ionic liquids exhibit good chemical and mechanical stability. They are also sufficiently deformable to facilitate their integration into automotive parts, such as onto curved surfaces. This improves the lifespan of the reflective module. Therefore, these examples are particularly suitable for automotive applications. Furthermore, solid polymer electrolytes can therefore be in gel form. Electrolytes in gel form overcome the disadvantages of liquid and solid electrolytes, such as the low chemical stability and leakage risk of liquids, and the slow switching and lack of transparency of solids. They are also easier to provide and more suitable for flexible substrates. Improved stability of the chemicals involved in the redox process is further enhanced, thereby improving the reversibility of color changes and opening up a wide range of possibilities for expanding electrochromic color palettes.

[0035] According to one example, a solid polymer electrolyte comprises a polymeric ionic liquid mixed with a polymeric matrix and / or the polymeric ionic liquid is cross-linked.

[0036] According to one example, the electrochromic layer and preferably the solid polymer electrolyte have a substantially greater than or equal to 10 at room temperature (basically 25°C). -4 S / cm, for example, basically includes 10 -4 S / cm and 10 -2 Ionic conductivity between S / cm. These ranges of values ​​can be obtained more specifically when the solid polymer electrolyte contains an ion gel.

[0037] According to one example, the electrochromic layer and preferably the solid polymer electrolyte has a concentration of substantially less than or equal to 10 at room temperature (essentially 25°C). -4The ionic conductivity in S / cm. This range can be obtained more specifically when the solid polymer electrolyte contains a polymeric ionic liquid.

[0038] According to one example, a solid polymer electrolyte is based on at least one polymer selected from the group consisting of: polyethers, polycarbonates, polyesters, polynitriles, polyols, polyamines, polysiloxanes, fluoropolymers, biopolymers and their derivatives.

[0039] As an example, electrochromic molecules are organic molecules. Therefore, deposition methods become easier and production costs are reduced. A wide variety of colors can also be obtained. This is because organic electrochromic molecules, and especially viologen, have many redox forms with different colors.

[0040] According to one example, electrochromic molecules have a molar mass of less than or equal to 600 g / mol due to their form. Therefore, the solubility of electrochromic molecules in solid polymer electrolytes can be improved, particularly for organic molecules. Furthermore, a small potential difference, typically about ± 2 V, is sufficient to modulate the redox form of the electrochromic molecule and change the reflected color, and more particularly in the visible light range. The response time of electrochromic molecules after the application of a potential difference is also very fast, for example, about one second or a few seconds.

[0041] According to one example, electrochromic molecules are selected from the group consisting of: viologens, spiropyrans, bipyridines, carbazoles, methoxyphenyls, quinones, tetrathiofulvalenes, phenylenediamines, pyrazolines, porphyrins, and especially thiophene-porphyrins, furan-porphyrins, triphenylamines, and their derivatives.

[0042] These molecules are particularly well-suited for reliably and repeatably tuning the wavelength of reflected beams in the visible light range over time. This is because these molecules exhibit good chemical stability and reversible transitions between different redox forms over a large number of continuous cycles. This improves the lifetime of the reflective module.

[0043] As an example, an electrochromic layer contains a variety of different electrochromic molecules. Therefore, depending on the absorption peaks of the different redox forms of each electrochromic molecule, a wide variety of color hues can be obtained when a reflected beam is sensed.

[0044] As an example, when no potential difference is applied, the electrochromic molecule is colorless. Therefore, when no potential difference is applied, only the Fabry-Perot effect contributes to the wavelength of the reflected beam. The application of a potential difference allows the redox form of the electrochromic molecule to be altered. Therefore, when no potential difference is applied, the transmittance of the electrochromic layer is at its maximum. This is particularly true for small electrochromic molecules (whose molar mass is, for example, less than or equal to 600 g / mol), and especially for small organic electrochromic molecules.

[0045] According to one example, an electrochromic molecule has at least one colorless form and at least one colored form.

[0046] According to one example, when no potential difference is applied, the electrochromic layer is colorless, wherein the electrochromic layer does not exhibit an absorption peak in the visible light range. When it is in a colored form, the electrochromic molecules preferably have at least one absorption peak in the visible light range.

[0047] According to one example, preferably, the electrochromic layer has a transmittance of greater than or equal to 80%, at least when no potential difference is applied. This transmittance further improves the transmittance of the incident beam to the electrochromic layer, and improves the transmittance of the reflected beam to the outside of the module after the incident beam has been reflected by the mirror.

[0048] According to one example, the electrochromic layer has a thickness substantially greater than or equal to 50 nm. According to one example, the electrochromic layer has a thickness substantially less than or equal to 300 nm. According to one example, the electrochromic layer has a thickness substantially between 50 nm and 300 nm, preferably between 100 nm and 200 nm. This thickness range allows the electrochromic layer to construct beams reflected in the visible light range by using constructive interference of the Fabry-Perot effect. These thickness ranges are also particularly suitable for synergistically tuning the wavelength between the Fabry-Perot effect and the electrochromic molecules.

[0049] According to one example, the reflective module, and more particularly the multilayer stack, does not include an electrolyte layer other than the electrochromic layer. In one example, at least one solid polymer electrolyte and at least one electrochromic molecule are mixed in the electrochromic layer.

[0050] According to one example, the reflective module, and more specifically the multilayer stack, comprises a single electrochromic layer.

[0051] In one example, the multilayer stack is covered by a second substrate. Therefore, the reflective module is protected by this substrate, which is particularly advantageous for applications in the automotive field.

[0052] Preferably, the first substrate and (where applicable) the second substrate are flexible substrates. This further minimizes the risk of poor electronic contact between the electrode substrate and the electrochromic layer, and thus limits the risk of colorless regions appearing in the electrochromic layer even when a potential difference is applied.

[0053] Preferably, the first substrate and (where applicable) the second substrate are based on polyethylene terephthalate or derivatives thereof.

[0054] According to one example, the first electrode and the second electrode each form a layer, and the first electrode and the second electrode are arranged on both sides of the multilayer stack.

[0055] In one instance, the system includes a power source configured to apply a potential difference applied to the stack.

[0056] According to one example, the system includes a plurality of reflective modules juxtaposed in at least one direction parallel to and preferably coinciding with the main extension direction of the reflective modules. Thus, the plurality of modules form a plurality of pixels, the reflected wavelength of which can be adjusted according to the potential difference applied to each reflective module. Therefore, it will be understood that the system allows for dynamic display of reflected wavelengths module by module. Due to the presence of a solid polymer electrolyte in the electrochromic layer, the system eliminates complex fluid connections, especially since the system includes multiple reflective modules. To eliminate these connections, those skilled in the art would alternatively seek to adjust the thickness of the same conductive polymer layer within the same reflective module to change the reflected wavelength based on existing solutions. However, this does not allow for dynamic adjustment of the pixel-to-pixel wavelength.

[0057] In one instance, the system was configured to apply a potential difference independently between each reflective module.

[0058] According to one example, the system also includes a lateral light source and a waveguide covering the at least one reflective module, the waveguide being configured to transmit a beam of light from the light source to the at least one reflective module. When ambient light is insufficient to achieve visible light reflection of the desired wavelength, such as at night, the system is therefore equipped with its own light source to inject a beam into the reflective module and emit a reflected beam of the desired wavelength. Therefore, compared to existing systems using active lighting modules, this system offers reduced power consumption while allowing good visibility at night.

[0059] For example, waveguides are equipped with decoupling elements, such as prisms or suspended particles, which allow light propagating within them to return to at least one of the reflective modules.

[0060] According to one example, a multilayer stack consists of at least one layer forming a metallic mirror and one or more electrochromic layers.

[0061] According to one example, the multilayer stack is made in direct contact with a first substrate and, where applicable, in direct contact with a second substrate. According to another example, the multilayer stack is made in direct contact with a first electrode and a second electrode.

[0062] A substrate or layer “based on” substance A means a substrate or layer that contains only substance A or substance A and possibly other substances.

[0063] Several embodiments of the invention, comprising sequential steps of a production method, are described below. Unless explicitly stated otherwise, the adjective “sequential” does not necessarily imply (although generally preferred) that the steps follow one another immediately; intermediate steps may separate them.

[0064] In addition, the term "step" refers to a portion of a method being performed, and a set of sub-steps can be specified.

[0065] Furthermore, the term "step" does not necessarily mean that the actions taken during a step are simultaneous or immediately consecutive. In particular, some actions in the first step may be followed by actions related to different steps, and other actions in the first step may be repeated thereafter. Therefore, the term "step" does not necessarily mean a single and indivisible action in time and in the sequence of stages of a method.

[0066] As stated, in the context of this invention, the thickness of a layer or substrate is measured in a direction perpendicular to the surface on which the layer or substrate has the greatest extension. Therefore, the thickness is taken in a direction perpendicular to the main surface of the substrate on which each layer is located.

[0067] As stated herein, in the context of this invention, the terms “on / to,” “surmounts,” “covers,” “underlying,” “facing,” and their equivalents do not necessarily mean “in contact with.” Thus, for example, depositing, transferring, bonding, assembling, or applying a first layer onto a second layer does not necessarily mean that the two layers are in direct contact with each other, but rather that the first layer at least partially covers the second layer by direct contact or by being separated from it by at least one other layer or at least one other element.

[0068] In this patent application, unless otherwise expressly stated, the term “integration” used to describe the connection between two parts means that the two parts are connected / fixed relative to each other according to all degrees of freedom.

[0069] In the following detailed description, terms such as “longitudinal,” “lateral,” “upper,” and “lower” may be used; these terms should be interpreted relative to the assembled position of the components of the reflective module or system, such that the direction of the primary extension plane of the layer perpendicular to the stack is equivalent to the vertical direction. Lateral or transverse dimensions refer to dimensions in planes parallel to or coinciding with the primary extension plane of the layer in the stack.

[0070] "Parallelized" elements here means that these elements are arranged side by side in their main extension plane or vertically to each other in the direction of the stack, which is perpendicular to the main extension plane.

[0071] "Contact" means that fine interfaces can exist, for example, due to process variability.

[0072] The parameter "substantially equal to / greater than / less than" means that the parameter is equal to / greater than / less than the given value, within 10% of that value. The parameter "substantially included between two given values" means that the parameter is at least equal to the minimum given value, within 10% of that value, and at most equal to the maximum given value, within 10% of that value.

[0073] "Nano" and more specifically "nano thickness" refers to a size greater than or equal to 1 nm and strictly less than 1 µm, or more specifically, a thickness.

[0074] In the context of this invention, the visible light range corresponds to a wavelength range between 350 and 900 nm, and preferably between 400 and 800 nm.

[0075] The expression "A and / or B" means (A), (B), or (A and B). The expression "A, B and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0076] The multilayer electroactive reflective module 1 and the reflective system 3 including the multilayer electroactive reflective module 1 will now be described according to several exemplary embodiments.

[0077] For example Figure 1As shown, the reflective module 1 includes a first substrate 10 on which a multilayer stack 18 is deposited. The substrate has a lower surface 10a and an upper surface 10b. The stack 18 may be disposed on the upper surface 10b, and, where applicable, on an electrode 12, which itself is disposed on the upper surface 10b. The multilayer stack 18 is configured to receive an incident beam 2 and reflect a reflected beam 2'. The incident beam 2 has a wavelength spectrum. Using the Fabry-Perot effect, a portion of this wavelength spectrum will be transmitted through constructive interference and then reflected from the metal mirror 14 to form the reflected beam 2'. Furthermore, the multilayer stack 18 is configured such that the wavelength of the reflected beam 2' can be tuned by changing the optical properties of the multilayer stack 18 when a potential difference is applied. Therefore, it should be understood that the wavelength of the reflected beam 2' can be reduced compared to the spectrum of the incident beam 2.

[0078] To allow this reflection, the multilayer stack 18 includes at least one reflective metallic mirror 14 and an electrochromic layer 15. This layer 15 is configured to emit a wavelength determined by constructive interference using the Fabry-Perot effect and is configured to have optical properties that are modulated according to the applied potential difference. More specifically, the absorption spectrum of the electrochromic layer 15 can be changed according to the applied potential difference. It should be noted that the term "wavelength" used for the reflected beam 2' is not limited to a single wavelength but can specify a range of wavelengths.

[0079] The Fabry-Perot effect will be described first. An electrochromic layer 15, typically about one hundred nanometers or several hundred nanometers thick, forms a Fabry-Perot cavity, into which the incident beam 2 is confined. The cavity produces interference of a defined wavelength from the light it receives. This interference causes multiple reflections of light of a given wavelength propagating within the cavity.

[0080] In addition to and in concert with this constructive interference phenomenon, because the electrochromic layer 15 contains at least one electrochromic molecule 17, the electrochromic layer 15 can exhibit absorption at some wavelengths similar to those when using pigments or dyes. One or more electrochromic molecules 17 are molecules that are part of at least one redox pair, which can be converted from one redox form to another when a potential difference is applied in a conductive medium.

[0081] At least one redox form of the electrochromic molecule 17 is referred to as "colored," meaning that the absorption spectrum of the molecule in that redox form has an absorption peak in the visible light range. Therefore, by removing the absorption wavelength from the spectrum of the beam, the Fabry-Perot effect is used to alter the constructive interference and the spectrum of the reflected beam 2' at the output of module 1. The electrochromic molecule 17 can have various colored forms, as will be seen in more detail below with reference to specific examples. At least one redox form of the electrochromic molecule 17 can also be "colorless," meaning that the absorption spectrum of the molecule in that redox form does not have an absorption peak in the visible light range.

[0082] Depending on the potential difference applied to the electrochromic layer 15, it should be understood that one or more electrochromic molecules 17 may exist in one redox form or another redox form, and thus the optical properties of layer 15 can be tuned. Once the electrochromic molecule 17 has converted to its redox form after a potential difference has been applied, the electrochromic molecule 17 can retain that form. This is because electrochromism can also benefit from a kind of "memory effect." Therefore, it is not necessary to maintain a potential difference to obtain a specific color, even though a potential difference can or even advantageously be applied at regular intervals to improve the maintenance of the module's color. Thus, the consumption of the reflective module can be reduced.

[0083] To alter the optical properties of the electrochromic layer 15, module 1 includes two electrodes 12 and 13 configured to apply a potential difference to the stack 18, and more specifically, to the electrochromic layer 15. The first electrode 12 and the second electrode 13 are electrically connected to the multilayer stack 18 on both sides. These two electrodes 12 and 13 can each form a layer disposed on both sides of the stack 18, such as… Figure 1 As shown in the figure. Alternatively, these electrodes may be provided to be connected to the stack 18 without forming individual layers, such as forming on the edge of the stack 18 and electrically connecting to the conductive portion of the stack.

[0084] To apply the potential difference, the reflection system 3 may include a power supply 30, such as an electronic controller, electrically connected to the first electrode 12 and the second electrode 13. According to one example, the absolute value of the potential difference applied by the source 30 is between 0 V (excluding) and 2 V, preferably between 0 V (excluding) and 1 V.

[0085] When an electrical potential difference is applied, the electrochromic molecule 17 can be altered via a redox reaction. During this reaction, for example, by… Figure 2 As shown, the redox form of electrochromic molecule 17 is altered. Figure 2An electrochromic layer 15 is shown comprising a mixture of a solid polymer electrolyte 16 and electrochromic molecules 17. For example, when no potential difference is applied, the redox form of the molecules (e.g., their neutral form) is colorless. The electrolyte 16 contains ions 160 to form an ionicly conductive medium. When a potential difference is applied, the electrochromic molecules can be oxidized and can be converted to a colored redox form. Therefore, it will be understood that the wavelength of the beam 2' exiting module 1 can thus be adjusted based on the applied potential difference. For example, when another potential difference is applied, the electrochromic molecules can be converted to their initial redox form or can be converted to another redox form. It should be noted that, depending on the properties of the electrochromic molecules 17, the molecules can be oxidized and / or reduced in multiple redox forms.

[0086] When this potential difference is applied, the electrochromic layer 15 exhibits little to no change in its thickness d15, which contrasts with existing solutions that provide thickness variation to alter the transmission wavelength through interference using the Fabry-Perot effect. Typically, when this potential difference is applied, the thickness d15 of the electrochromic layer 15 changes by less than 1% of its initial thickness; preferably, the thickness of the electrochromic layer 15 is constant.

[0087] To form an ionicly conductive medium in which the redox reaction will occur, and thus ensure ion transport between the two electrodes and charge balance from the redox process, the electrochromic layer 15 comprises a solid polymer electrolyte 16. Therefore, the solid polymer electrolyte has good ionic conductivity. Thus, the electrochromic layer 15 is in a solid or semi-solid state, for example, in the form of a gel or semi-solid material. This avoids leakage and reduces the size and weight of the reflective module 1. The architecture of the reflective module 1 is also simplified. Therefore, the reflective module 1 can be more easily integrated into existing components, such as into automotive parts in the context of automotive applications, as described in more detail below. Many solid polymer electrolytes can be manufactured from commercially available products, making it easier to manufacture the module 1 and reducing its production cost.

[0088] The reflective module 1 may further include a second substrate 11 covering the multilayer stack 18 and, where applicable, the second electrode 13. The second substrate 11 has a lower surface 11a and an upper surface 11b. The stack 18 may be disposed on the lower surface 11a and, where applicable, on the electrode 13, which itself is disposed on the lower surface 11a. Thus, the multilayer stack 18 and the electrodes 12, 13 may be sandwiched between the first substrate 10 and the second substrate 11. The second substrate 11 may form the incident refractive interface of the incident beam 2 and the exit refractive interface of the reflected beam 2'. Therefore, the second substrate 11 is preferably configured to allow these beams 2, 2' to pass through. The substrate 11 preferably has a transmittance greater than or equal to 75%, preferably substantially equal to 80%.

[0089] The reflection module 1 or the system 3 including it can be integrated into parts such as automotive parts. Figure 3 The illustration shows the front portion of the car's front hood, which includes the reflective system 3 at its center. It is possible that the reflective module or reflective system 3 can be integrated with other parts, such as inside the passenger compartment or on other parts of the vehicle body.

[0090] Preferably, the reflective module 1 has a reaction time of approximately one second, preferably less than or equal to several seconds, preferably less than or equal to 1 second, and more preferably less than or equal to 200 ms. This is particularly related to the properties of the electrochromic molecule 17, the ionic conductivity of the solid polymer electrolyte 16, and the thickness of the electrochromic layer 15.

[0091] According to one example, the reflective module 1 has a reflectivity of incident beam 2 ranging from 50% to 90%.

[0092] Now refer to Figure 4 and 5 Describe a specific example of System 3.

[0093] System 3 may include at least one reflection module 1, and preferably multiple reflection modules 1. For example... Figure 4 As shown, each reflective module 1 may preferably include a mask 111 configured to partially block the transmission of the incident beam 2 and the reflected beam 2'. The mask 111 may, for example, be placed on the upper surface 11b of the second substrate 11. The mask 111 may define a region 111 that blocks the transmission of light and a region 111a that allows the incident beam 2 and the reflected beam 2' to pass through. For the reflective module 1, the mask 111 can therefore be used to reveal the pattern. It should be noted that the mask 111 may be shared by multiple juxtaposed reflective modules 1.

[0094] According to one example, system 3 may include a plurality of reflective modules 1 juxtaposed in at least one direction, referred to as "juxtaposed," parallel to or coinciding with the main extension direction of these modules 1. Preferably, the reflective modules 1 are juxtaposed with planes parallel to or coinciding with the main extension plane of these modules 1 in at least two directions, referred to as "juxtaposed." Thus, system 3 forms a pixel array, with each reflective module 1 capable of forming one pixel. System 3 allows for the dynamic display of reflected wavelengths module by module.

[0095] The fact that the electrolyte is in solid or semi-solid form means that a more complex architecture with multiple reflective modules 1 can be obtained. This is because it allows for the elimination of the reservoir of liquid electrolyte accompanying each pixel, and thus limits the fill factor of the resulting pixel array. It also simplifies the system compared to using a remote liquid electrolyte reservoir whose fluid connection to each reflective module 1 would be complex.

[0096] System 3 may include, for example, at least five juxtaposed reflection modules 1, preferably at least five juxtaposed reflection modules 1 in each juxtaposed direction.

[0097] To adjust the wavelength of the beam 2' exiting the module, specifically module-by-module, the power supply 30, or equivalent voltage source 30, can be configured to apply a potential difference to each reflective module 1 independently. Each reflective module 1 can have its own power supply 30. Therefore, modules 1 can be controlled independently for pixelated animation. Alternatively, a single power supply 30 can be provided, for example, applying the same voltage to all reflective modules to simplify the control circuitry.

[0098] As will be understood from the foregoing description, the reflective module 1 can reflect the incident beam 2 from the environment outside the reflective module 1, such as ambient light. In dimly lit environments, such as at night, maintaining display functionality through one or more reflective modules 1 can be advantageous. For this purpose, and as... Figure 5 As shown, the reflection system 3 may include at least one, preferably lateral, light source 31. The light source 31 is configured to emit a light beam 2''. This light beam 2'' then assumes the function of the incident light beam 2 described above. Therefore, according to this example, it will be understood that the reflection module 1 can reflect the incident beam 2 originating from the environment and / or the light beam 2'' from the light source 31. The system 3 may also include a waveguide 32 configured to transmit the light beam 2'' from the light source 31 to one or more reflection modules 1. For this purpose, the waveguide 32 may include a total internal reflection element configured to conduct the light beam 2'' from the source. Depending on the reflection angle of the beam in the waveguide, the beam 2'' from the source 31 may be transmitted to the reflection module 1 or may continue to propagate in the waveguide 32.

[0099] For example, waveguide 32 may include prism 320, which is configured to alter the optical path of a portion of the beam 2'' from source 31 in order to send it to a corresponding reflecting module 1. Those skilled in the art can manufacture waveguides consistent with the arrangement of one or more reflecting modules 1. Depending on the juxtaposition of the reflecting modules 1, prism 320 may be arranged, for example, at regular intervals along waveguide 32. Those skilled in the art can provide other structures as alternatives to or supplements to prism 320, such as suspended particles.

[0100] The reflective module 1 may have a portion 1a offset from the multilayer stack 18, which includes corresponding portions 110, 130, 120, 100 of the substrate 10 and / or 11 and / or electrodes 12 and / or 13. Therefore, the surfaces 10b and 11a of the first substrate 10 and / or the second substrate 11, and, where applicable, the electrodes 12, 13, are only partially covered by the stack 18, as by... Figure 4 and Figure 7B As shown. Figure 7C A top view of the first substrate 11 covered by mirror 14 illustrates this. This makes it easier to electrically connect the reflective module 1 to the power supply 30. For example, the first substrate 10 and / or the second substrate 11, preferably having associated electrodes 12, 13, can extend a distance in at least one direction of the main extension plane of the layers of the stack 18, a distance greater than the corresponding distance associated with the cost of the stack 18. Part 1a can be connected to the power supply 30. Part 1a also makes it easier to integrate the stack 18 into the system 3 without having to connect it to the power supply 30.

[0101] An example of the dimensions of the reflective module 1 will now be given. Each module 1 can extend in the main extending plane of the layers of the stack 18. In this plane, each reflective module 1 can have a lateral dimension in a direction perpendicular to each other, the values ​​of which range from a few millimeters for small surfaces to even several meters for large surfaces. The thickness of the multilayer stack 18 can be substantially greater than or equal to 50 nanometers (nm) and substantially less than or equal to 350 nanometers (nm). Therefore, it will be understood that the reflective module is compact and thus easier to integrate into existing parts (e.g., automotive parts), especially compared to existing solutions using liquid electrolytes.

[0102] As by Figure 7B and Figure 7C As shown, the first substrate 10 and / or the second substrate 11 may extend a certain distance d1 in at least one direction of the main extension plane of the layers of the stack 18, the distance being less than or equal to 5 mm, preferably less than or equal to 3 mm, relative to the layers of the stack 18.

[0103] The reflection module 1 will now be described in more detail for each component.

[0104] The first substrate 10 and / or the second substrate 11 are preferably flexible substrates. This makes it easier to integrate the reflective module into existing parts and increases the mechanical strength of the reflective module 1. A material or layer is considered flexible if the mechanical and electrical properties of the film remain unchanged even under high stress of 2.5% at concave and convex radii of curvature of 0.5 mm. The deformation (flexibility) of the reflective module 1 can be evaluated using the following equation: Deformation = (ts - tp - tf) / (2.rc), where: -ts is the thickness of one or more layers of substrate 10, 11. -tp is the total thickness of the 18 layers in the stack. -tf is the total thickness of electrode layers 12 and 13. -rc is the radius of curvature.

[0105] According to one example, substrate 10 and / or second substrate 11 can be manually deformed without any tools. As seen above, at least the second substrate 11 can have a transmittance greater than or equal to 75% in the visible spectrum. According to one example, the first substrate 10 and / or second substrate 11 are based on or made of a polymer. More specifically, the first substrate 10 and / or second substrate 11 are based on or made of polyethylene terephthalate (PET), PMMA, or derivatives thereof. It should be noted that other polymers are conceivable.

[0106] In the case of multiple juxtaposed reflective modules 1, the first substrate 10 and / or the second substrate 11 may be shared by multiple modules 1. Alternatively, each module may include its own one or more substrates, which are different between different modules 1. This makes it easier to manufacture each reflective module 1, which are then assembled together, for example on a common support 33, as... Figure 5 As shown in the figure.

[0107] Electrodes 12 and 13 may be in the form of layers deposited on the first substrate 10 and the second substrate 11, respectively. For example, electrodes 12 and 13 are based on or made of indium tin oxide (ITO).

[0108] The metal mirror 14 can be formed from at least one metal layer 140, for example, based on or made of aluminum. This results in good reflection of the incident beam 2. The metal mirror 14 may also include a layer that allows for better chemical compatibility with the electrochromic layer 15. For this purpose, the metal mirror 14 may include a gold-based layer 142. Therefore, the gold layer 142 can be in contact with the electrochromic layer 15 without the risk of degradation of that layer or the metal mirror 14. It should be noted that multiple metal mirrors 14 can be used in the stack 18, or even in the reflective module 1. For example, one or more substrates 10 and one or more mirrors 14 can be provided stacked. To attach the gold layer 142 to the aluminum layer 140, the mirror 14 may include a chromium-based or chromium-made adhesive layer 141 between these layers 140, 142. The metal mirror preferably has a nanometer thickness, that is, a thickness of less than 1 µm. For example, the aluminum layer 140 may have a thickness d140 that is substantially between 40 nm and 80 nm, for example between 50 nm and 70 nm, and preferably substantially equal to 50 nm. The chromium layer may have a thickness d141 that is substantially equal to 5 nm. The gold layer may have a thickness d142 that is substantially equal to 7 nm.

[0109] In the electrochromic layer 15, the solid polymer electrolyte 16 may include an ion gel comprising a polymer matrix and an ion liquid, and / or, for example, a polymer ion liquid having a polymer matrix.

[0110] In examples of ionogels, the polymer matrix can be selected from polyvinyl alcohol (PVA), polyethers such as polyethylene glycol (PEG), and polysulfides. The ionic liquid can be selected from the following components: 1-Ethyl-3-methylimidazolium chloride; -1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (abbreviation EMIM TFSI); -1-Ethyl-3-methylimidazolium trifluoromethanesulfonate (abbreviated as EMIM trifluoromethanesulfonate); - Choline-based biocompatible ionic liquids (ILs).

[0111] In a manner known to those skilled in the art, polymeric ionic liquids are ionically conductive polymers obtained by the polymerization of ionic liquid monomers. According to some examples, and in a manner known to those skilled in the art, the polymeric ionic liquid can be a solid and have sufficient mechanical strength to form layer 15. According to other examples, the polymeric ionic liquid may have insufficient strength to form layer 15 on its own, and then they are typically soluble upon exposure to organic solvents. To provide a polymeric ionic liquid with mechanical properties, the electrolyte may comprise the polymeric ionic liquid and a polymer matrix forming a mechanical support. Alternatively or additionally, the solid polymeric liquid can be crosslinked with crosslinkable chemical bonds (e.g., C=C bonds). After crosslinking, the resulting polymer network is insoluble.

[0112] Therefore, solid polymer electrolytes exhibit good ionic conductivity, allowing redox reactions in the electrochromic layer 15 and improving the stability of chemicals involved in the redox process. Ion gels based on polymer ionic liquids and solid polymer electrolytes exhibit good chemical and mechanical stability. In particular, they have a wide electrochemical stability window. For example, solid polymer electrolytes have an electrochemical stability window greater than or equal to 3 V, such as substantially equal to 3.2 V.

[0113] Furthermore, the ionogels based on polymer ionic liquids and the solid polymer electrolytes are sufficiently deformable and stretchable to accommodate the deformation and mechanical stress of the module during use, which is particularly advantageous for automotive applications. According to one example, the Young's modulus of the solid polymer electrolyte is substantially between 0.2 and 4 MPa. The elongation at break can be substantially greater than or equal to 100%, for example, substantially between 150% and 160%. Therefore, the reflective module 1 still has a long lifespan despite the stress that may be applied to the module. The ionogels based on polymer ionic liquids and the solid polymer electrolytes also enable patterning, for example, using photolithography. In particular, the patterns can be used to produce decorative films. Preferably, the electrochromic layer 15 has a transmittance of greater than or equal to 80%.

[0114] According to one example, the electrochromic layer 15 can also have a density greater than or equal to 1.10 at room temperature. -4 Ionic conductivity in S / cm. At room temperature, ionic conductivity can be substantially within the range of 10. -4 S / cm and 10 -2 The ionic conductivity can be between S / cm. -3 S / cm. These ionic conductivities are particularly available due to the use of ion gels. In the case of polymeric ionic liquids, the solid polymeric electrolyte layer can also have a conductivity of less than or equal to 1.10 at room temperature. -4Ionic conductivity in S / cm.

[0115] The solid polymer electrolyte 16 may be based on at least one polymer selected from the following: polyethers, polycarbonates (e.g., polybutylene glutarate, abbreviated PBG), polyesters, polyacrylonitrs (e.g., polyacrylonitrile, abbreviated PAN), polyols (e.g., polyvinyl alcohol, abbreviated PVA), polyamines (e.g., polyethyleneimine, abbreviated PEI), and polysiloxanes (e.g., polydimethylsiloxane, abbreviated PDMS), fluoropolymers (e.g., polyvinylidene fluoride, abbreviated PVDF, and poly(vinylidene fluoride-copolymer-hexafluoropropylene), abbreviated P(VDF-copolymer-HFP)), biopolymers (e.g., lignin, chitosan, and cellulose) and their derivatives. The solid polymer electrolyte may, for example, comprise copolymers, wherein at least one of the monomer units corresponds to one of the polymers mentioned above.

[0116] Examples of cations that can be used to form ionic liquids, and in a manner known to those skilled in the art, are 1,3-dialkylimidazolium, N-alkylpyridinium, tetraalkylammonium, tetraalkylphosphonium, and N-alkylpyrrolidineium. Examples of anions that can be used are bis(trifluoromethanesulfonyl)imide, hexafluorophosphate, tetrafluoroborate, trifluoromethanesulfonate, chloride, bromide, iodide, nitrate, and acetate. These ions can have different hydrophobic or hydrophilic properties. Depending on, for example, the nature of the polymer matrix, or the desired hydrophobic or hydrophilic properties, it will be understood that the ions used to form the ionic liquid (polymer or otherwise) can be modified.

[0117] The electrochromic layer 15 preferably has a thickness between 50 and 300 nm, and more preferably between 100 and 200 nm. In practice, since the electrochromic molecules are distributed within the matrix formed of the solid polymer electrolyte 16, the electrochromic layer 15 does not need to have a greater thickness. Therefore, the compactness of the reflective module 1 is improved. The limitation of the thickness d15 of the electrochromic layer 15 also benefits high transmittance, and thus benefits the transmittance of the incident beam 2 and the reflected beam 2'. Preferably, the electrochromic molecules 17 are uniformly distributed within the solid polymer electrolyte 16.

[0118] According to one example, the electrochromic molecule is an organic molecule, such as a polymer molecule or a macromolecule. Preferably, the electrochromic molecule has a molar mass of less than or equal to 600 g / mol. Therefore, many molecules are commercially available to reduce the production cost of module 1. For example, electrochromic molecule 17 can be selected from: viologens, spiropyrans, bipyridines, carbazoles, methoxyphenyls, quinones, tetrathiofulvalenes, phenylenediamines, pyrazolines, porphyrins, and especially thiophene-porphyrins, furan-porphyrins, triphenylamines, and their derivatives. For example, viologens are produced by the quaternization of piperidine.

[0119] Examples of the chemical formulas of these compounds are given below.

[0120] [Chemical Formula 1] [Chemical Formula 2] Those skilled in the art are well capable of recognizing derivatives of these molecules that may possess electrochromic properties, such as those described, for example, in Stolar, Monika. “Organic electrochromic molecules: synthesis, properties, applications and impact” Pure and Applied Chemistry, Vol. 92, No. 5, 2020, pp. 717-731. https: / / doi.org / 10.1515 / pac-2018-1208. Derivative molecules can be, for example, molecules with substituents, such as carbonaceous groups or chains carrying or not carrying at least one heteroatom.

[0121] The following redox equilibrium illustrates the redox form of viologen during a series of redox reactions: [Chemical Formula 3] Violet can typically have three different redox forms: colorless, blue / purple, and orange / red.

[0122] The following redox equilibrium illustrates the two redox forms of spiropyran through examples: [Chemical Formula 4] Spiropyrans can typically have two different redox forms with the following potential difference: colorless (0 V), orange-pink when ΔV = 2 V (e.g. at -1.2 V and 0.8 V).

[0123] The electrochromic layer 15 may also contain other chemical compounds, and in particular participate in the redox reaction of the electrochromic molecule 17. For example, the electrochromic layer 15 contains a redox medium. The redox medium may be, for example, potassium ferrocyanide and potassium ferricyanide p, and / or the TEMPO (2,2,6,6-tetramethylpiperidin-1-yl)oxy or (2,2,6,6-tetramethylpiperidin-1-yl)oxoalkyl group.

[0124] Now refer to Figures 6 to 10 A method for producing a reflective module 1 is described below, based on several exemplary embodiments. It should be noted that the method may include any steps capable of obtaining the characteristics of the reflective module 1 described above. Specific examples of production formulations are also given. Deposition parameters and techniques can be configured to obtain the thicknesses described above.

[0125] As by Figure 6 As shown, the method includes supplying a first substrate 10 including a first electrode 12. The method may include, for example, depositing the first electrode 12 on the first substrate 10 by depositing an ITO layer on the first substrate 10, and more particularly depositing it on the substrate 10b thereon.

[0126] The method then includes forming a multilayer stack 18 as described above.

[0127] For this purpose, the method may include depositing a metal mirror 14 on the first substrate 10, and more particularly on the first electrode 12, such as Figures 7A to 7C As shown above, mirror 14 may comprise a series of layers of metal. These layers 140, 141, 142 may be formed using any physical deposition technique, such as cathode sputtering, electron beam evaporation, flash evaporation, or induction evaporation.

[0128] On the formed metal mirror 14, the method may include depositing an electrochromic layer 15. For this purpose, many deposition techniques are conceivable, particularly depending on the properties of the solid polymer electrolyte 16. It should be noted that, alternatively or in combination, according to variants not shown, an electrochromic layer may be deposited on the second electrode 13.

[0129] For this purpose, many deposition techniques can be envisioned, particularly depending on the properties of the solid polymer electrolyte 16. Deposition can be done dropwise using a blade, employing centrifugation (often specified by the term "spin coating"). For example, and as by... Figure 8A and Figure 8B As shown, depositing an electrochromic layer may include depositing a precursor solution to form layer 15'. According to one example, the precursor solution contains between 1% and 10% by mass, preferably substantially 5% electrochromic molecules. This deposited layer 15' can then be formed by heat treatment and / or by UV radiation and / or by drying.

[0130] According to the first specific example, the deposited electrochromic layer 15 may include: - Prepare an aqueous solution of 4% PVA, viologen, and a 1:1 molar mixture of potassium ferrocyanide and potassium ferricyanide. - Mix the aqueous solution with the borax aqueous solution at a volume ratio of 4:1 until a gel is obtained. - The mixture is deposited onto the metal mirror 14. -Dry at room temperature to obtain bubble-free layer 15.

[0131] According to the second specific example, the deposited electrochromic layer 15 may include: - Prepare solutions of 2 mM spiropyran and 4 mM TEMPO ((2,2,6,6-tetramethylpiperidin-1-yl)oxy or (2,2,6,6-tetramethylpiperidin-1-yl)oxoalkyl) in BMIM-TFSI (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide). - The prepared solution was mixed with a solution of P(VDF-copolymer-HFP) at a mass ratio of 1:20 to acetone to obtain a BMIM-TFSI ratio of 83.3% by mass. - The mixture is deposited onto the metal mirror 14. -Dry at room temperature for 24 h to obtain layer 15.

[0132] According to this example, the solid polymer electrolyte layer has a transmittance of 83%.

[0133] Preferably, the reflective module 1 is manufactured as two sub-modules 1' and 1'' that can be more easily assembled. Therefore, depending on the layer deposited for the electrochromic layer 15, the formation of layer 15 is independent of the formation of mirror 14 or the second electrode 13. According to this example, after the electrochromic layer 15 has been deposited, the first sub-module 1' is obtained. The second sub-substrate 1'' is then manufactured for subsequent assembly of them.

[0134] It should be noted that, alternatively, the reflective module 1 can be formed layer by layer from the first substrate 10 by sequentially stacking the layers to be deposited, according to the same technique described. However, this carries the risk of damaging the electrochromic layer 15 when depositing the mirror 14 or the second electrode 13 (which will then cover the electrochromic layer 15).

[0135] The production of the second submodule 1'' will now be described. A second substrate 11 may be supplied, which includes a second electrode 13 deposited on a lower surface 11a, as described by... Figure 9 As shown, the method may include, for example, depositing the second electrode 13 on the second substrate 11 by depositing an ITO layer on the second substrate 11.

[0136] Then reflection module 1 can be obtained by assembling or equivalently transferring submodules 1' and 1''. For example, and as... Figure 10As shown, the exposed surfaces 15a and 13a of the electrochromic layer 15 and the second electrode 13 can be made to contact each other. To secure the sub-modules 1' and 1'', it is possible to, for example, perform the assembly while the electrochromic layer 15 has not yet fully cured, which is completed after the sub-modules 1' and 1'' have been assembled.

[0137] For each module, the method for producing the reflective system 3 may include the production steps presented above. The method for producing the reflective substrate 3 may also include electrically connecting the power supply 30 to the first electrode 12 and the second electrode 13. The method may further include the step of mounting multiple reflective modules 1 on, for example, a common support 33. Figure 5 As shown in the figure. The method may also include the step of mounting additional components of the system (e.g., a lateral light source and a waveguide or mask 111).

[0138] This invention is not limited to the embodiments described above, but extends to all embodiments covered by this invention. The invention is not limited to the examples described above. Many other variant embodiments are possible without departing from the scope of the invention, for example by combining the features described above. For example, a reflective module may be provided comprising, for example, multiple mirrors and a substrate alternating with each other. Furthermore, depending on the nature of the deposited layer, other deposition techniques can be envisioned by those skilled in the art. Moreover, features described with respect to one aspect of the invention may be combined with other aspects of the invention.

Claims

1. A multilayer electroactive reflective module (1) for automotive parts, the multilayer electroactive reflective module comprising: ●First substrate (10). ● A multilayer stack (18) disposed on the first substrate (10) and configured to receive an incident light beam (2) and reflect a reflected light beam (2') having a defined wavelength depending on the potential difference applied to the stack (18), the multilayer stack (18) comprising at least one layer forming a metal mirror (14). ● A first electrode (12) and a second electrode (13), which are electrically connected to the multilayer stack (18) on both sides and are configured to apply the potential difference. The multilayer stack (18) is characterized in that it includes an electrochromic layer (15) having a nanometer thickness (d15) and covering the metal mirror (14), the electrochromic layer comprising: ●At least one solid polymer electrolyte (16). ● At least one electrochromic molecule (17) different from the at least one solid polymer electrolyte (16) in order to change the absorption of the electrochromic layer (15) according to the potential difference applied to the stack (18).

2. The module (1) as described in the preceding claim, wherein, The solid polymer electrolyte (16) comprises: ● Ionic gels containing a polymer matrix and an ionic liquid, and / or ● Polymer ionic liquids.

3. Module (1) as described in any of the preceding claims, wherein, The solid polymer electrolyte (16) is based on at least one polymer selected from the group consisting of: polyether, polycarbonate, polyester, polynitrile, polyol, polyamine, polysiloxane, fluoropolymer, biopolymer and its derivatives.

4. The module as claimed in any of the preceding claims, wherein, The electrochromic molecule (17) is an organic molecule.

5. The module as claimed in any of the preceding claims, wherein, The electrochromic molecule (17) has a molar mass of less than or equal to 600 g / mol.

6. Module (1) as described in any of the preceding claims, wherein, The electrochromic molecule (17) is selected from the group consisting of: viologens, spiropyrans, bipyridines, carbazoles, methoxyphenyls, quinones, tetrathiofulvalenes, phenylenediamines, pyrazolines, porphyrins, and especially thiophene-porphyrins, furan-porphyrins, triphenylamines, and their derivatives.

7. Module (1) as described in any of the preceding claims, wherein, When no potential difference is applied, the electrochromic molecule (17) is colorless.

8. Module (1) as described in any of the preceding claims, wherein, When no potential difference is applied, the electrochromic layer (15) has a transmittance of 80% or greater.

9. Module (1) as described in any of the preceding claims, wherein, The electrochromic layer (15) has a thickness (d15) between 50 nm and 300 nm.

10. Module (1) as described in any of the preceding claims, wherein, The multilayer stack (18) is covered by a second substrate (11).

11. An electroactive reflective system (3) for automotive parts, comprising at least one reflective module (1) as described in any of the preceding claims.

12. The system (3) of the preceding claim, comprising a plurality of said reflective modules (1) juxtaposed in at least one direction parallel to the main extension direction of said reflective modules (1).

13. The system (3) of any one of the preceding two claims further includes a lateral light source (31) and a waveguide (32) covering the at least one reflective module (1), the waveguide being configured to transmit a light beam (2") from the light source (31) to the at least one reflective module (1).

14. A method for producing a reflective module (1) as described in any one of claims 1 to 10, comprising: ●Supply the first substrate (10) including the first electrode (12), and supply the second electrode (13). ● The at least one layer forming the metal mirror (14) is deposited on the first substrate (10). ● The electrochromic layer (15) is deposited on one of the metal mirror (14) and the second electrode (13). ● The first substrate (10) and the second electrode (13) are assembled by means of the electrochromic layer (15) and another of the metal mirror (14) and the second electrode (13) such that the multilayer stack (18) is connected to the first electrode (12) and the second electrode (13) on both sides.

15. A motor vehicle part (4) comprising a reflective module (1) as claimed in any one of claims 1 to 10 or a reflective system (3) as claimed in any one of claims 11 to 13.

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