WO2024126861A1

WO2024126861A1 - Exterior device with a display module with a layer of electrochromic material

Info

Publication number: WO2024126861A1
Application number: PCT/EP2023/086217
Authority: WO
Inventors: Eduardo ALVEAR; Sidahmed BEDDAR; Hafid El-Idrissi
Original assignee: Valeo Vision
Priority date: 2022-12-16
Filing date: 2023-12-15
Publication date: 2024-06-20
Also published as: FR3143718A1

Abstract

The invention relates to an exterior device (20) for a motor vehicle, the device comprising a display module (1). The display module comprises at least one layer of electrochromic material (10) which is able to receive incident light rays via a first surface (13) and to return light rays from among the incident light rays from the first surface. The display module further comprises a metal mirror (11) arranged on a second surface of the layer of material. According to the invention, the layer of electrochromic material is configured to form a Fabry-Pérot cavity, such that the returned light rays have a wavelength within a range that is defined at least by properties of the material of the layer and by a thickness of the layer of electrochromic material.

Description

External equipment with a display module with a layer of electrochromic material

The present invention relates to the field of exterior equipment for motor vehicles, in particular exterior equipment having signaling or aesthetic functions. The invention applies in particular, but not exclusively, to the display of one or more colors via a display module.

It is now common to create lighting functions inside a motor vehicle, for information signaling purposes, for aesthetic purposes of personalization or to create an atmosphere. It is also now desirable to allow light functions outside the vehicle, to be visible to an observer located outside the vehicle, for information signaling purposes or for aesthetic purposes.

It is known to use screens, such as LCD screens.

However, such technology is not only expensive but also sensitive to environmental conditions such as temperature, humidity or UV radiation. It is therefore unsuitable for exterior uses, the exterior equipment of a motor vehicle being subject to variable environmental conditions, with bad weather, and also being exposed to mechanical shock.

What's more, it is preferable to have a flexible and lightweight display or light module in order to facilitate its integration into any type of equipment. This is particularly the case on the exterior of a motor vehicle, in which the equipment, such as the various bodywork elements, has non-flat surfaces.

In addition, the aforementioned solution has the disadvantage of high energy consumption, all the more significant as the surface area of the equipment in which it is desired to integrate a display module is large.

Finally, the aforementioned display module has the disadvantage of being difficult to read in sunny weather, the contrast with ambient light being too low.

There is therefore a need to have exterior equipment for a motor vehicle comprising a light, robust, inexpensive display module, consuming little energy, easy to integrate and having good visibility during the day, particularly in sunny weather.

The present invention improves the situation.

au moins une couche de matériau électrochrome présentant une première surface, ladite couche de matériau électrochrome étant apte à recevoir des rayons lumineux incidents par ladite première surface et à renvoyer des rayons lumineux parmi les rayons lumineux incidents depuis ladite première surface;
un miroir métallique agencé sur une deuxième surface de la couche de matériau.

A first aspect of the invention relates to exterior equipment for a motor vehicle, the equipment comprising a display module comprising:

at least one layer of electrochromic material having a first surface, said layer of electrochromic material being capable of receiving light rays incident by said first surface and of returning light rays among the light rays incident from said first surface;
a metal mirror arranged on a second surface of the material layer.

According to the invention, said layer of electrochromic material is configured to form a Fabry-Pérot cavity so that said returned light rays have a wavelength included in an interval defined at least by properties of the electrochromic material of said layer and/ or by a thickness of said layer of electrochromic material.

The use of electrochromic material forming a Fabry-Pérot type cavity, also called electrochromic material with Fabry-Pérot effect, makes it possible to display a given color on the display module. In fact, this cavity produces, from the light it receives, interference of a specific wavelength. This interference results in multiple reflections of colored rays propagating inside the cavity. Thus, it is through a phenomenon of interference, and not absorption as when pigments or dyes are used, that the layer of material produces, for an observer, a colored rendering. Such a color is called “structural”, because it is obtained by interference of incident light rays with the electrochromic material.

During the day, especially when ambient light is high, no energy consumption is required to display such a structural color, as the layer of material can operate passively. The display module therefore allows considerable energy savings compared to solutions of the prior art. What is more, such an electrochromic layer is thin at a sub-wavelength scale, for example of the order of a few nanometers thick or between 50 and 800 nm, for example between 75 and 300 nm, and therefore both space-saving and lightweight. The display function being structurally linked to the layer of electrochromic material, the display module is also very robust, particularly to mechanical shocks and temperature variations. A Fabry-Pérot cavity can return approximately between 60% and 90% of the incident light intensity, which allows good visibility of the display module in sunny weather.

Here, the incident light rays can come from natural light (such as sunlight) or from an artificial light source (such as the case of an electroluminescent source).

In an exemplary embodiment, the first surface and the second surface of the layer of electrochromic material are arranged facing each other. In this way, light rays arriving on the second surface are reflected directly towards the first surface. It is therefore a simple and effective provision.

According to embodiments, the electrochromic material is part of a family of organic transparent conductive oxide materials (otherwise called the "TCO" family, abbreviated from the English terms "transparent conductive oxide"), in particular a transparent conductive polymer type PEDOT:PSS, PEDOT:tos, PMMA, T34bT or cellulose.

Such a material makes it possible to create a Fabry-Pérot cavity, which is flexible and transparent.

For example, the metal mirror can be made from aluminum (Al), chromium (Cr) or gold (Au) or even alloys of at least two of these three metals.

In one embodiment, the external equipment may further comprise a control element capable of controlling an electrical stimulus, such as an electrical voltage, applied to the display module so as to vary said properties of the electrochromic material (e.g. the refractive index) and/or the thickness of the layer of electrochromic material. For example, transparent conductive polymers of the PEDOT:PSS, PEDOT:tos or cellulose type are particularly suitable for this embodiment.

Specifically, the display module comprises an electrolyte layer arranged in contact with the layer of electrochromic material so that under electrical stimulation, for example when applying an electrical voltage to the electrolyte layer, the ions from the electrolyte layer migrate into the electrochromic material layer. The quantity of “migrating” ions depends on the value of the applied electrical quantity. The more “migrating” ions there are, the thicker the layer of electrochromic material becomes.

Oxidation-reduction reactions can occur between the layer of electrochromic material and the “migrating” ions so as to modify the thickness and/or properties of this layer. Thus, the layer of electrochromic materials is electrochemically adjustable.

It is thus made possible to display a color with a dynamic variation of the color or light intensity, by controlling a parameter of the electrical stimulus, in particular the electrical voltage. Such control can be ensured in practice by low voltage levels, less than 1V in absolute value for each layer of electrochromic material, for example between -1V and +1V, which results in low energy consumption.

In practice, in order to apply the electrical voltage, the layer of electrochromic material can be at least partially surrounded by an electrolytic solution. Such an electrolytic solution can be applied by a dip coating method, followed by crosslinking by UV irradiation, or “UV-Curing”.

In practice, the electrolyte layer is connected to at least two electrodes, for example to a working electrode (called a “working electrode” in English) and an electrode system comprising a counter electrode (called a “counter electrode” in English). and a reference electrode.

In addition, the control element may be able to receive data from a set of at least one sensor, and the control element may be able to control the electrical stimulus applied to the display module as a function of the data of the assembly of at least one sensor.

This makes it possible to adapt the color(s) displayed to the environment of the vehicle.

In addition, the assembly may include at least one ambient light sensor.

It is thus made possible to vary the voltage applied to the display module depending on the ambient brightness. In particular, the light intensity of the display module can be controlled according to the ambient brightness, which improves the visibility of the display module.

Alternatively or in addition, the assembly may include a proximity sensor capable of detecting an object or a person in a detection field.

It is thus made possible to vary the color upon detection of an object or a person near the vehicle. The display module can thus signal information.

According to embodiments, the display module may include several layers of electrochromic material arranged next to each other in a line or matrix, and at least two layers of electrochromic material may have different thicknesses.

It is thus made possible to produce patterns, color gradation, or even an entire image when the number of layers of electrochromic material is greater than a few dozen, or even a few hundred or thousands. As a variant or in addition, the display may include an electrolyte layer associated with each layer of electrochromic material. In this case, the control element may be able to control voltages respectively applied to the electrolyte layers so as to vary the thickness and/or the properties of the layers of electrochromic material independently of each other, so as to dynamically vary an image displayed by the display module.

For example, the electrolyte layer can be associated with the layer of electrochromic material by encapsulation, that is to say that the layer of electrochromic material is encapsulated in an electrolytic envelope.

It is thus made possible to vary a pattern, an image, the color of an image and/or its light intensity. Such a variation may make it possible to signal information or fulfill an aesthetic function.

For example, the display module may comprise a plurality of layers of electrochromic material. Each package includes at least two layers of electrochromic material arranged next to each other and configured to return different wavelengths in the visible spectrum when supplied with voltage. The control element is configured to control voltages respectively applied to the electrolyte layers so as to vary the thickness and/or properties of the layers of electrochromic material within a package independently of each other. In this way, each packet can return several possible colors, namely the color of the layer of electrochromic material supplied (when the other layer of electrochromic material is not supplied with voltage), or the mixed color of the colors returned by each layers of electrochromic material when they are all supplied with voltage. With this embodiment, each packet can form one pixel of the pixelated image and each pixel can be of different colors.

According to embodiments, the display module may have a thickness of less than 100 micrometers, for example between 40 and 60 micrometers.

This makes it easier to integrate the display module into the equipment. The size and weight of the equipment are also reduced.

According to embodiments, the exterior equipment may be a motor vehicle grille, further comprising a perforated structure comprising at least one opening, said at least one opening is arranged facing the first surface of the display module.

It is thus made possible to produce a motor vehicle grille at lower cost, robust and with low energy consumption.

Alternatively, the exterior equipment may be a vehicle body element.

It is thus made possible to replace the paint of the vehicle with the layer of electrochromic material forming a Fabry-Pérot cavity, which improves its robustness and makes it possible to vary the color of the vehicle when the voltage across the display module is controlled.

According to embodiments, the display module can be included between a surface of the external equipment and a covering element.

The covering element is transparent or semi-transparent so as to allow the light rays reflected by the display module to pass through. Thus, the display module is mechanically protected, particularly from bad weather, which improves its durability. In addition, the cover element can protect the display module from UV radiation.

According to embodiments, the external equipment may further comprise a transparent light module arranged opposite the first surface of the display module so as to illuminate said at least one layer of electrochromic material.

It is thus made possible to display the structural color(s) of the display module regardless of the ambient brightness. This is because when driving at night, the ambient light may be dim, which cannot guarantee a sufficient amount of light reflected by the display module to meet the required light performance. The light module as proposed provides a solution to this problem. Indeed, the additional supply of light coming from the light module makes it possible to provide the display module with the light necessary to achieve the expected light performance both day and night.

In addition, the control element may be able to activate at least one light source of the light module when a measurement of ambient brightness is below a given threshold.

Thus, activation of the light module is optimized, since it is only turned on when the ambient light is too low. The energy consumption of external equipment is thus optimized.

au moins un guide de lumière comprenant une nappe de guidage flexible transparente ou semi-transparente, la nappe de guidage flexible étant apte à recevoir des rayons lumineux par au moins une tranche d’injection de ladite nappe de guidage flexible et à renvoyer les rayons lumineux dans une direction sensiblement normale à une surface de la nappe de guidage flexible ;
au moins une source de lumière apte à injecter de la lumière dans le guide de lumière.

In addition or as a variant, the transparent light module may include:

at least one light guide comprising a transparent or semi-transparent flexible guide sheet, the flexible guide sheet being able to receive light rays through at least one injection edge of said flexible guide sheet and to return the light rays in a direction substantially normal to a surface of the flexible guide sheet;
at least one light source capable of injecting light into the light guide.

It is thus made possible to use a flexible, robust, lightweight, low-cost light module capable of illuminating a large surface area without requiring numerous light sources.

In the aforementioned example, the guide sheet may comprise return elements, also called decoupling elements, making it possible to reflect light rays towards said at least one layer of electrochromic material in order to illuminate it. The return elements can be microstructures, prisms, or even suspended particles integrated into the guide sheet. Advantageously, the return elements are arranged on or closest to the face of the guide sheet which is adjacent to said at least one layer of electrochromic material.

In addition, the light guide further comprises at least one light injection element capable of receiving light from the light source and distributing the light in the flexible guide sheet. Here, the light injection element is an intermediate element placed between the guide sheet and the light source. Thus, the light injection element makes it possible to collect the majority of the light emitted by the source and distribute it in the guide sheet. The light loss is therefore reduced compared to the configuration in which the light source directly emits light into the light guide sheet via the injection edge. This loss is all the more significant when there is a difference between the size of the light source and the thickness of the light guide sheet.

In addition, the light module may comprise more than two light guides placed next to each other so as to form a matrix of light guides and the flexible guide sheet of each light guide being arranged facing at least a layer of material.

It is thus possible to selectively illuminate several parts of the display module.

According to embodiments, the flexible guide sheet of each light guide may have a thickness of between 10 and 1000 micrometers.

Such a thickness allows significant flexibility of the flexible guide sheet, and facilitates its integration, particularly on curved supports.

According to embodiments, each light guide of the light module may comprise a film made of polycarbonate, PC, polymethyl methacrylate, PMMA, thermoplastic polyurethane, TUP, or polyethylene terephthalate, PET.

Such materials make it possible to produce a flexible and transparent guide sheet. It is notably made possible to use a roll-to-roll manufacturing procedure, in which the flexible film is used both to form the film of the flexible guide sheet but also the associated injection element.

According to embodiments, the flexible guide sheet of each light guide of the light module comprises a film comprising microstructures etched by ultraviolet printing so as to return the light injected into the light guide according to a given pattern. The latter is also called a “light pattern” which can be observed from the outside when the light source associated with the light guide is turned on.

Such microstructures make it possible to distribute the light emitted by the light module according to a pattern on each flexible guide sheet.

In addition, for each flexible guide sheet, a surface density of microstructures can decrease with the distance from the light injection edge of the guide sheet into which the light is injected.

It is thus made possible to return light homogeneously.

According to embodiments, each injection element may comprise a plurality of injection layers, each injection layer being capable of receiving light from one end of the guide and of guiding the light to a given longitudinal position of the injection element, the longitudinal positions of the injection layers being all different so as to distribute the light longitudinally in the injection element.

Thus, it is possible to distribute light homogeneously in the light injection section of the flexible guide sheet, which improves the projection quality of the pattern engraved in the flexible guide sheet.

Another object of the invention relates to a motor vehicle comprising external equipment presented previously.

Other characteristics and advantages of the invention will appear on examination of the detailed description below, and the appended drawings in which:

illustrates a display module of exterior equipment for a vehicle according to embodiments of the invention;

illustrates a display module of exterior equipment for a vehicle according to other embodiments of the invention;

illustrates a structure of outdoor equipment according to embodiments of the invention;

illustrates a structure of outdoor equipment according to a first embodiment of the invention;

illustrates a structure of outdoor equipment according to a second embodiment of the invention;

illustrates a structure of outdoor equipment according to a third embodiment of the invention;

illustrates a structure of outdoor equipment with display module and light module, according to embodiments of the invention;

illustrates a light guide of a light module of exterior equipment for a motor vehicle, according to a first embodiment of the invention;

illustrates a light module of exterior equipment for a motor vehicle according to one embodiment of the invention;

illustrates a light guide of a light module of exterior equipment for a motor vehicle according to one embodiment of the invention;

illustrates exterior equipment for a motor vehicle according to one embodiment of the invention;

illustrates a light module of exterior equipment for a motor vehicle, according to a second embodiment of the invention;

illustrates a light module of exterior equipment for a motor vehicle, according to a third embodiment of the invention;

illustrates a light module of exterior equipment for a motor vehicle, according to a fourth embodiment of the invention.

The description focuses on the characteristics which distinguish the external equipment and the light module from those known in the state of the art.

There presents a side view, in an XZ plane, of a display module 1 according to embodiments of the invention.

The display module 1 comprises a layer of electrochromic material 10 forming a Fabry-Pérot type cavity. Electrochromic means a material that changes color when an electrical voltage is applied to it for a short period of time. The color change is due to the fact that only one specific type of wavelengths, for example wavelengths of a specific value or in a specific visible color spectrum, can come out of the layer of electrochromic material in function of the value of the applied electrical quantity. These specific wavelengths correspond to a color in the visible spectrum and arrive at the eyes of an observer. This therefore gives the impression that the layer of material has changed color. The material maintains the new color as long as electrical voltage is applied to it.

The layer of electrochromic material 10 comprises two surfaces 13 and 14, substantially parallel to each other, one surface 13 being oriented towards the outside of the display module 1 and another surface 14 being arranged against a metal mirror 11 An incident light wave, having a given spectrum of wavelengths, enters through the surface 13 then interferes with the electrochromic material 10. The interference phenomenon leads to the electrochromic material 10 returning light rays through the surface 13. , only in a restricted range of wavelengths, or more simply, according to a given color.

The color returned by the layer of electrochromic material 10 is conditioned both by the thickness of the cavity but also by the intrinsic properties of the electrochromic material, its permittivity in particular, as well as by the metallic mirror 11 used. The metal mirror 11 can for example be made of chrome, aluminum or gold. Here, the metal mirror 11 is also used as a reflecting means to reflect the light rays which go against it towards the surface 13 of the layer of electrochromic material 10. Thus, the returned light rays exit the display module through the same surface where the incident light rays arrive. This surface is oriented outwards so as to be visible from the outside.

Layers 10 and 11 can be attached to a substrate 12. No restriction is attached to the material of the substrate. Preferably, layers 10, 11 and 12 are sufficiently thin for display module 1 to be flexible. The display module 1 may in particular have a thickness of around 50 micrometers, for example between 10 and 100 micrometers. The layer of electrochromic material 10 can have a thickness varying from a few nanometers to a value between 75 and 300 nm.

The material 10 is preferably a polymer, such as a PEDOT type polymer, or poly(3,4-ethylenedioxythiophene), or PEDOT:Tosylate. Of course, other materials can be used as long as they have the properties suitable for an automotive application such as high ionic conductivity, a transparent physical appearance, that is to say a given color defined by the The thickness of the layer, or colorless, that is to say black, in a resting state, flexible, the electro-optical properties to form a Fabry-Perot cavity in an excited state. Additionally, the material can be packaged as a solid cell.

The electrochromic material may be a transparent conductive oxide, or TCO for “Transparent Conductive Oxide” in English. In particular, among the organic electrochromic materials, the electrochromic material may be a transparent conductive polymer of the PEDOT:PSS, PEDOT:tos, PMMA, T34bT type or polycarbonate.
PEDOT:PSS refers to poly(3,4 ethylenedioxythiophene): sodium poly(styrene sulfonate);
PEDOT:Tos refers to poly(3,4 ethylenedioxythiophene):Tosylate;
PMMA designates PolyMethyl MethAcrylate;
T34bT designates 2-alkylthieno[3,4-b]thiophene.
Such a display module advantageously makes it possible to display a color on the surface 13 passively, without the need for a light source, only incident light being required. The incident light can for example be ambient light, such as sunlight or from a light source external to the display module 1. Depending on the external light source, such a display module is capable of returning approximately between 60% and 90% of the incident light intensity, passively. For example, the light source producing the incident light, when it is a white light-emitting diode, has a flux of 400 lumen, the electrochromic material returns a luminous flux between 240 lumen and 360 lumen.

The thickness of the layer of electrochromic material 10 has an influence on the color perceived by an observer. For example, a PEDOT layer with a thickness e1 equal to 220 nm, when it receives light with a broadband light spectrum S(λ), produces by reflection a red color of wavelength λ ₁ . A PEDOT layer, when it receives light with a broadband light spectrum S(λ), with a thickness e2 equal to 170 nm, produces by reflection a green color of wavelength λ ₂ . A PEDOT layer with a thickness e3 equal to 130 nm, when it receives light with a broadband light spectrum S(λ), produces by reflection a blue color of wavelength λ ₃ .

No restriction is otherwise attached to the substrate 12, which can be made of silicon, PolyCarbonate PC, or PolyMethyl MethAcrylate, PMMA.

The color thus emitted by the layer of material 10 is said to be a structural color.

More details on such a display module 1, as well as on how to choose a color from the UV treatment which is applied to the electrochromic material 10, the intensity of the treatment and its duration in particular, depending on the material electrochromic, are detailed in the article “ Tunable Structural Color Images by UV-Patterned Conducting Polymer Nanofilms on Metal Surfaces ”, by Shangzi Chen et Al, Advanced Materials, 2021, 33, 2102451, published by Wiley-VCH GmBH. Furthermore, the layer of electrochromic material may contain other elements, for example metallic sub-layers arranged in contact with the electrochromic material, electrodes, and/or an electrolytic element. These elementary components participate in forming the layer of electrochromic material forming a Fabry-Pérot cavity.

There illustrates a display module 1 according to embodiments of the invention. The display module 1, in addition to the elements presented with reference to the , may comprise a control element 15 capable of controlling a parameter of an electrical stimulus applied to the display module 1, in particular an electrical voltage applied to the display module 1. Such an electrical voltage can in particular be applied via two electrodes placed in a nickel oxide counter-electrode layer and in an electrolytic solution forming part of the display module 1, and not shown on the . Thus, a lower electrode is placed between the metal mirror 11 and the substrate 12, while an upper electrode is above the counter electrode, and the electrolytic solution is included between the counter electrode and the layer of material 10. L The aforementioned article details in particular how such an electrolytic solution can be arranged relative to the electrochromic material 10. It can be similar to an encapsulation of a PDLC film, for “ Polymer Dispersed Liquid Crystals ” in English. Alternatively, encapsulation can be carried out by dip-coating , followed by crosslinking by UV irradiation. No restrictions are attached to the composition or dosage of the electrolyte solution. It may for example be a 0.1M solution of sodium dodecylbenzeneulfonate NaDBS in water.

The application of a voltage to the display module 1 makes it possible both to modify the thickness of the layer of electrochromic material 10, but also to oxidize or reduce it, and thus to change the nano-optical properties. layers of material 10. Controlling the applied electrical voltage thus makes it possible to vary the structural color returned by the electrochromic material 10 via its surface 13, but also to vary the luminous intensity of the light returned.

It is thus made possible to apply an electrical voltage as a function of the ambient light intensity, in order to maintain, for example, a stable light intensity of the electrochromic material 10. For this purpose, the control element 15 may be able to receive measurements from at least one sensor 16. The sensor 16 may for example be able to acquire measurements of ambient light intensity. The control element can then control the electrical voltage to be applied depending on the ambient light intensity.

In addition or as a variant, the set of sensors 16 may include a proximity sensor capable of determining an object or a person near the sensor 16, that is to say within a given perimeter around the sensor 16. Depending on of detection information of an object or a person, the control element 15 can vary the light intensity and/or the color emitted by the layer of electrochromic material 10, by controlling the voltage which it is applied.

The control element 15 can vary the applied voltage between - 1V and 1V for example.

There presents a display module 1 according to other embodiments of the invention. Compared to display module 1 presented on the , the display module 1 of the may comprise at least two layers of electrochromic material 10.1 and 10.2, arranged on the same metal mirror 11 and the same substrate 12, one next to the other, thus forming at least two pixels of the display module 1.

Alternatively, a metal mirror dedicated to each layer of electrochromic material 10.1 and 10.2 can be provided, with a single substrate 12.

Still as a variant, a dedicated metal mirror 11 and substrate 12 are provided for each layer of electrochromic material 10.1 and 10.2.

Material layers 10.1 and 10.2 may have undergone the same UV treatment or may have undergone different UV treatments. Thus, the layers of electrochromic material 10.1 and 10.2 can be capable of returning light in the same color, or in distinct colors. In particular, the layers of materials 10.1 and 10.2 can have distinct thicknesses, at rest, when no tension is applied to them.

No restrictions are attached to the number of layers of material or their respective arrangements. On the , two layers of electrochromic material 10 are distributed at distinct positions along the axis next to each other in a line, along the X or Y axis, or in a matrix along the X and Y axes.

It is thus made possible to produce a color image, each layer of electrochromic material 10 forming a pixel of the image.

Alternatively, a pixel is made up of several layers of electrochromic material 10 arranged in a matrix, each layer of electrochromic material 10 having a square shape in the XY plane. The pixel can then have a dimension of the order of a millimeter, for example between 1mm ² and 10mm ² . It can be a square of 1mm by 1mm, or 3mm by 3mm for example. A pixel can thus comprise several hundred layers of electrochromic material 10 placed next to each other. Each pixel comprises layers of electrochromic material which are thus driven together, i.e. identical voltages are applied to them, so that the entire pixel has the same color. The voltages can be controlled by the control element 15.

The resolution of the image is therefore proportional to the number of pixels thus formed.

The color and light intensity of the image can be controlled by the control element 15, capable of individually controlling the electrical voltage applied to each layer of electrolyte, or layer of electrolytic solution, associated with each layer of electrochromic material 10. A control element 15 can be provided for each layer of electrochromic material 10, or for a set of layers of electrochromic material 10 forming a pixel.

Note that the control element 15 is optional, and that the display module 1 may be able to passively return light in a pattern defined by the respective colors of the at least two layers of electrochromic material 10.1 and 10.2.

faire varier l’intensité lumineuse et/ou la couleur d’une image prédéfinie par les couleurs respectives et l’agencement respectif des couches de matériau électrochrome 10; et/ou
contrôler différemment les couches de matériau électrochrome de manière à faire varier dynamiquement le motif affiché ou l’image affichée.

The control element 15 can thus:

vary the light intensity and/or color of a predefined image by the respective colors and the respective arrangement of the layers of electrochromic material 10; and or
differently controlling the layers of electrochromic material so as to dynamically vary the displayed pattern or displayed image.

There illustrates a display module 1 according to other embodiments of the invention.

In these embodiments, three layers of electrochromic material 10.11, 10.12 and 10.13 are placed next to each other in the display device 1, forming a triplet of layers of electrochromic material. Here, a triplet is a particular form of a packet which denotes two or more layers of electrochromic material arranged together.

One of the layers of electrochromic material 10 may have intrinsic properties and a thickness such that it is capable of returning blue light when a first voltage is applied to it by the control element 15. For example, it is This is the first layer of electrochromic material 10.11. The first voltage can be equal to 0.3V.

Another layer of electrochromic material 10 may have intrinsic properties and a thickness such that it is capable of returning green light when a second voltage is applied to it by the control element 15. For example, it is of the second layer of electrochromic material 10.12. The second voltage can be equal to 0.6V.

Another layer of electrochromic material 10 may have intrinsic properties and a thickness such that it is capable of returning red light when a third voltage is applied to it by the control element 15. For example, it is of the third layer of electrochromic material 10.13. The third voltage can be equal to 0.9V.

Advantageously, the three layers of electrochromic material 10.21, 10.22 and 10.23 can be such that they do not return any wavelength in the visible spectrum when no voltage is applied to them.

The width, or dimension along the X axis, of each of the layers of electrochromic material 10.11, 10.12 and 10.13, is sufficiently small to be below the resolution of the human eye. Thus, an observer cannot separate the light coming from it and the rays coming from the three layers of electrochromic material 10.11, 10.12 and 10.13 combine to form a white light beam. For example, the dimension of a layer along the X axis can be less than 20 micrometers, for example less than 10 micrometers.

Display module 1 thus appears white.

It is thus made possible to alternately display a white surface or a black surface by controlling the voltage applied by the control element 15. Controlling the display of a white or black surface may depend on received sensor data of the assembly of at least one sensor 16, as previously explained for the other embodiments.

In these embodiments, the display module 1 comprises several triplets of layers of electrochromic material 10 presented with reference to the . Each triplet of layers of electrochromic material may be similar to the triplet of layers of electrochromic material 10.11 to 10.13 of the .

un premier triplet de couches de matériau électrochrome 10.11, 10.12 et 10.13;
un deuxième triplet de couches de matériau électrochrome 10.21, 10.22 et 10.23; et
un troisième triplet de couches de matériau électrochrome 10.31, 10.32 et 10.33.

The display module 1 thus comprises at least two triplet layers of electrochromic material 10 placed one next to the other. In the example of the , the display module 1 comprises three triplets of layers of electrochromic material 10 placed in line at distinct positions along the X axis, namely:

a first triplet of layers of electrochromic material 10.11, 10.12 and 10.13;
a second triplet of layers of electrochromic material 10.21, 10.22 and 10.23; And
a third triplet of layers of electrochromic material 10.31, 10.32 and 10.33.

The triplets of layers of electrochromic material can be arranged on the same metallic mirror 11 or on respective metallic mirrors 11. Likewise, the triplets of layers of electrochromic material 10 on respective metallic mirrors 11 can be arranged on the same substrate 12 or on respective substrates 12.

It is thus advantageously made possible to display white light at several positions in layers of electrochromic material are distributed in a matrix so as to form a pixelated image, each triplet of layers of electrochromic material corresponding to a pixel of the pixelated image. Alternatively, a pixel is made up of several triplets of layers of electrochromic material arranged in a matrix, each triplet having a square shape in the XY plane. The pixel can then have a dimension of the order of a millimeter, for example between 1mm ² and 10mm ² . It can be a square of 1mm by 1mm, or 3mm by 3mm for example. A pixel can thus comprise several hundred triplets of layers of electrochromic material 10. Each pixel comprises triplets of layers of electrochromic material which are thus controlled together, that is to say that identical electrical voltages are applied to all the first layers of electrochromic material 10.11, 10.12 and 10.13, identical electrical voltages are applied to all second layers of electrochromic material 10.21, 10.22 and 10.23 and identical electrical voltages are applied to all third layers of electrochromic material 10.31, 10.32 and 10.33, so that an entire pixel is black or white. The voltages can be controlled by the control element 15, as for the embodiments of the . Here, by the application of the electric voltage to the layer of electrochromic material, we mean the application of the electric voltage to the layer of electrolyte solution associated with said layer of electrochromic material.

Advantageously, when the triplets of layers of electrochromic material form a matrix, controlling the voltages applied to the layers of electrochromic material 10 makes it possible to display a white or black pixel at each pixel. When the first, second and third voltages are applied to the layers of electrochromic material of the triplets forming a pixel, the pixel is white. When no voltage is applied, the pixel is black.

It is thus advantageously made possible to produce a black and white screen from the display module 1, with a dynamic variation of the displayed pattern. For example, the displayed pattern can vary dynamically as a function of sensor data from the set of at least one sensor 16. For example, a first given pattern can be displayed when an object or a person is detected in the surroundings of the sensor 16, and a second given pattern can be displayed when no object is detected in the surroundings of the sensor 16.

The dimension of the display module in the X direction or in the Y direction can be a few centimeters. For example, at least one of the dimensions can be between 5 and 25 centimeters. The display module can for example be square or rectangular in shape. The display module can have dimensions of 15cm by 15cm for example.

The same goes for the display module according to Figures 1a, 1b and 1c which can have the dimensions described above.

There presents exterior equipment 20 of a motor vehicle according to embodiments of the invention.

The external equipment 20 comprises at least one display module 1, according to one of the embodiments previously presented. It will thus be understood that the display module 1 can be that described with reference to the ,1b, 1c, 1d or 1e. Thus, the external equipment 20 optionally comprises a control element 15 as previously described and a set of at least one sensor 16 as previously described. Alternatively, the set of at least one sensor 16 can be external to the external equipment 20.

The external equipment 20 may include a surface 22 on which the display module 1 is mounted. The surface 22 is not necessarily flat and straight. It can be curved. Alternatively, the external equipment 20 does not include a surface 22, but a structure other than a surface on which the display module 1 is mounted.

No restriction is attached to the manner in which the display module 1 is mounted or fixed on the surface 22 or on the structure of the external equipment 20.

The external equipment 20 may further comprise a cover element 21 arranged on the display module 1, which is thus included between the cover element 21 and the surface 22. The cover element 21 can for example be a protective film having the same dimensions as the display module 1. Alternatively, the covering element 21 can have at least one dimension greater than that of the display module 1, so as to cover it and hold it against the surface 22.

The cover element 21 can provide mechanical protection of the display module 1. It can also provide a UV protection function.

No restriction is attached to the exterior equipment 20 of a motor vehicle, which may be a bodywork element, for example a side bodywork element, a front or rear grille of the vehicle, a door element or any other equipment having a surface facing outwards from the vehicle.

Such a grid 20 can be placed at the rear or at the front of a vehicle in particular.

There presents exterior equipment 20 of a motor vehicle according to a first embodiment.

In the first embodiment, the exterior equipment 20 is an exterior grille of a motor vehicle and the covering element 21 is a perforated structure comprising openings 25.

The display element 1 can be according to the embodiments of Figures 1a or 1b with a single layer of electrochromic material over the entire surface of the grid 21. The openings 25 only allow light to pass at certain points. predefined locations. Alternatively, the display element 1 comprises several layers of electrochromic material distributed in the plane of the surface 22 at the level of the openings 25.

There presents exterior equipment 20 of a motor vehicle 30 according to a second embodiment of the invention.

In the second embodiment, the exterior equipment 20 can be a bodywork element, such as a side bodywork element of the vehicle 30. In this case, the bodywork element 20 can have the color defined by the layer of electrochromic material 10, and by the voltage applied when the display module 1 comprises the control element 15, according to the embodiments of Figures 1a and 1b. Alternatively, the bodywork element 20 can have several colors, or even a colored or black and white pattern, when it comprises the display module 1 according to the embodiments of Figures 1c and 1e.

There illustrates exterior equipment 20 of a motor vehicle according to a third embodiment.

According to this third embodiment, the external equipment 20 comprises a display module 1 according to the embodiments of Figures 1c or 1e, capable of displaying a pattern 26 by spatial distribution of several layers of electrochromic material 10, or of several triplets of layers of material 10, or by controlling the layers of electrochromic material of a matrix extending in two dimensions.

It is thus made possible to display a pattern 26 having an aesthetic function or a signaling function. The pattern may be fixed, or may be dynamically controllable when the equipment includes the control element 15.

The exterior equipment according to the third embodiment can be arranged at the front or at the rear of a vehicle, for example in a central position.

There presents the structure of an exterior equipment 20 for a vehicle according to several embodiments of the invention.

Compared to the structure of the external equipment 20 presented with reference to the , the external equipment 20 further comprises a light module 100, 300, 400, 500 capable of illuminating the exterior surface 13 of the display module 1. The light module 100, 300, 400, 500 is advantageously transparent so as to allow to the light rays emitted by the layer of material 10 of the display module 1 to be emitted towards the outside of the external equipment 20.

It is thus made possible to illuminate the display module 1, particularly when the ambient light, whether from the sun or artificial, is too weak. The display module 1 can thus display one or more colors at night or when an external artificial source is too weak or non-homogeneous.

For this purpose, the transparent light module 100 can be controlled by the control element 15. Alternatively, a control element other than the element 15 can be provided and dedicated to controlling the ignition of the light module 100.

The control element 15 can in particular activate the light module 100 upon receipt of an external control signal, for example from a centralized control module of the vehicle, of the ECU type, for Electronic Control Unit for example, not shown on the . Alternatively, the control element 15 is capable of receiving ambient brightness measurements from all of at least one sensor 16. The control element 15 compares each ambient brightness measurement with a given threshold. If the ambient brightness is lower than the given or predetermined threshold, the control element 15 activates the light module 100.

The light module 100 can illuminate the entire surface 13, or a given part of the surface 13, in a homogeneous pattern or presenting spatial variations in light intensity.

No restrictions are attached to the light module 100, which is any transparent light module.

Preferably, the light module 100 comprises a light guide comprising a flexible guide sheet and an element for injecting light into the sheet, as described in the following.

There presents a light guide 105 of a light module of exterior equipment for a motor vehicle, according to embodiments of the invention.

The light guide 105 can thus be used in the light module 100, 300, 400, 500 placed opposite the display module 1, in the equipment 20 according to the embodiments of the described previously.

The light guide 105 comprises a flexible guide sheet 110 capable of receiving light rays through a light injection edge 114 and of returning the light rays in a direction Z substantially normal to a surface of the flexible guide sheet which is 'thus extends in an XY plane on the .

By guide sheet we mean an optical guide element of which one of the dimensions is much smaller than the other two dimensions in space, for example smaller by one or more orders of magnitude. As illustrated on the , we consider here a flexible guide sheet whose thickness along the Z axis is at least two orders of magnitude less than its dimensions along the plane XY in which the flexible guide sheet 110 extends.

The flexible guide sheet 110 may comprise a flexible film 111 at its heart comprising the light injection edge 114, being capable of guiding the light rays in an overall direction X, and comprising a set of microstructures 113 capable of returning the rays light guided in the flexible film 111 outside the flexible guide sheet 110, in particular in one or more directions substantially along the Z axis.

The flexible film 111 may be a substrate film made of polycarbonate, PC, polymethyl methacrylate, PMMA, thermoplastic polyurethane, TUP, or polyethylene terephthalate, PET. The flexible film 111 may have a thickness, i.e. a dimension along the Z axis, of between 12 and 1000 micrometers. More precisely, the thickness of the flexible film 111 can be between 50 and 1000 micrometers, for example between 200 and 500 micrometers. Alternatively, it is the flexible guide sheet 110 which has a thickness of between 200 and 1000 micrometers.

The aforementioned materials, associated with a low thickness as described above, make it possible to obtain a flexible and transparent film 111. Other materials can be provided for the composition of the flexible film 111. It is however preferable depending on the invention to provide deformable and transparent materials.

A fine coating of microstructures 113 can be attached to one of the faces of the flexible film 111, or be integrated into the flexible film 111. The coating of microstructures 113 can in particular have a thickness along the Z axis of less than 20 micrometers.

Such microstructures 113 may have a general bump shape, on which the light rays are reflected in a direction substantially along the Z axis. Such microstructures 113 may be capable of causing the light rays emerging from the flexible film 111 to form a pattern. . For this purpose, the microstructures 113 can be etched by ultraviolet printing, so as to reflect the light rays through the surface of the flexible film according to the desired pattern. For example, the microstructures 113 are distributed so as to project a homogeneous light over the entire surface of the flexible film 111. We then speak of a homogeneous pattern in what follows.

By microstructures 113 we mean structures, or irregularities of the flexible film, whose dimensions are less than a few micrometers. Microstructures thus also cover nanometric structures. Such sizes of microstructures 113 make it possible to ensure high transparency of the flexible film 111. In particular, a transparency of the order of 97% can be obtained in practice by the use of microstructures 113. As a variant, the guide sheet flexible can be semi-transparent. It will be understood, however, due to the arrangement of the light module 100 in front of the display module 1, that a high degree of transparency of the light module is preferred according to the invention, in particular greater than 80%.

Advantageously, the microstructures 113 can be distributed along the axis an injection element 120. In other words, the further away the microstructures 113 are from the light injection slice 114, the more densely they are grouped together. Such a distribution advantageously makes it possible to ensure a homogeneous distribution along the X axis of the light intensity of the pattern emitted by the flexible guide sheet 110.

The flexible guide sheet 110 may further comprise one or two optional protective layers 112.1 and 112.2, which make it possible to mechanically protect the flexible film 111. In addition, at least one of the protective layers 112.1 and 112.2 may include a treatment anti-UV, making it possible to protect the flexible film against UV rays, once the microstructures 113 have been etched. Without such UV protection, the pattern projected by the flexible guide sheet 110 is likely to degrade over time, particularly when exposed to the sun's rays.

The flexible film 111 and the protective layers 112.1 and 112.2 are shown spaced apart on the , for illustrative purposes only. It will be understood, however, that the protective layers 112.1 and 112.2 can be attached to the flexible film, in particular by lamination.

The propagation of light rays in the flexible film 111 is made by total internal reflection thanks to the difference between the refractive index of the flexible film 111 and that of a layer of glue or adhesive applied to at least one face of the flexible film.

The assembly of the flexible film 111 with the protective layers 112.1 and 112.2 can be done by gluing. Precisely, a layer of glue is located between the flexible film 111 and each protective layer 112.1 and 112.2, on both sides of the flexible film to adhere the protective layers to the flexible film.

The glue chosen is transparent and has a refractive index different from that of the flexible film so as to allow total internal reflection in the flexible film 111. In other words, by the difference in refractive index, the light rays propagating in the flexible film undergo total reflection when they meet the interface between the flexible film and the glue layer with an angle of incidence lower than the normal incidence. Thus, the guide sheet is capable of guiding light by total internal reflection of this light, for example from an entry zone, here from the injection section 114, to an exit zone.

The guide sheet 110 being flexible, it is not necessarily included in a plane but can be curved, depending on the position in which it is placed and the mechanical constraints applied to it.

The light guide 105 shown on the also comprises a light injection element 120, comprising a set of injection layers described with reference to Figures 2b and 2c, the light injection element being capable of distributing the light in the flexible guide layer 110 to different positions along the Y axis, along the light injection edge 114. The light is injected, at each position along the Y axis, in a direction substantially parallel to the X axis.

The light injection element 120 comprises an entrance surface 121 of rectangular or square section on the . However, the light injection element 120 may have an entrance surface having a different shaped section.

On the , the light injection element 120 is shown with an exit surface 122 extending in the direction Y and placed opposite the light injection edge 114. It will be understood on reading the description of Figures 2b and 2c that the exit surface 122 and the light injection edge 114 are combined, the flexible film 111 and the set of injection layers forming a single part.

The light injection element 120 further comprises the entrance surface 121, at one end of the light injection element 120, capable of receiving light rays from a light source external to the light guide 105 and not shown on the , and the light injection element 120 is able to guide the light longitudinally along the Y axis by distributing it on the exit surface 122. The distribution of light by the exit surface 122 will be better understood in the light of the description of Figures 2b and 2c.

There presents a light module 100 according to embodiments of the invention comprising a light guide 105 with an injection element 120 and a flexible guide sheet 110, and a light source 130.

In reference to the , the injection element 120 may comprise a plurality of injection layers 123.1, 123.2 and 123.3 capable of receiving light from the source 130 via the entrance surface 121 and of guiding the light to the assemblies of positions along the distinct Y axis 124.1, 124.2 and 124.3. As shown in Figures 2b and 2c, the injection layers 123.1, 123.2 and 123.3 can be in the same material and have the same thickness as the flexible film 111 of the guide layer 110. Thus, the light guide 105 can be obtained by a roll to roll manufacturing procedure, or R2R for "Roll To Roll in English", during which the flexible film 111 and the injection layers 123.1, 123.2 and 123.3 are obtained from the same roll of film flexible, the injection layers 123.1, 123.2 and 123.3 being cut at different positions in Y, in a cutting direction substantially parallel to the direction X. The injection layers thus obtained are flexible and can be folded as shown in the . The length of each injection sheet 123.1, 123.2 and 123.3 is chosen so that once folded, their ends together form the injection surface 121, as illustrated in the .

An injection element 120 with three injection layers has been shown in Figures 2b and 2c, for illustration purposes only. The injection element 120 may, however, comprise any set of injection layers comprising at least two injection layers.

No restrictions are attached to the light source 130. The light source 130 may be capable of generating light in a range of wavelengths. Such an interval can be centered around a visible color, in order to generate colored light, for example blue, red or green. Alternatively, and preferably according to the invention, the light source 130 can emit light rays over the entire range of wavelengths visible to the human eye, so as to generate white light. . It is thus possible to project broad spectrum light onto the display module 1 described previously.

The light source 130 can be controlled by a control element not shown, which may be the control element 15 previously described.

Alternatively, the light source 130 is not arranged directly facing the entrance surface 121 of the injection element 120, but the light module 100 further comprises an optical fiber placed between the source 130 and the injection element 120, which makes it possible to offset the source 130 relative to the light guide 105.

It is thus made possible to inject light at different longitudinal positions along the Y axis of the injection slice 114. Each longitudinal position of the injection slice 114 can correspond to a guide line of the flexible film 111 , capable of guiding the light along the X axis along such a guide line.

Such an association of a light guide 105 comprising a flexible guide sheet 110 and an injection element 120, and a source 130 thus makes it possible to project light in the Z direction through a flexible, transparent or semi-transparent surface. -transparent, with good surface homogeneity and in a given pattern.

In practice, such a light module can make it possible to emit light with a brightness of between 100 and 1000 Candelas per square meter, with a light extraction efficiency of between 25% and 80%.

Details of the structure and arrangement of these

elements

110, 120 and 130 are further described in the international patent application published under number WO2011130715A2.

By “pattern” we mean any distribution or predefined spatial distribution of the light intensity emitted by the light module. In particular, reference is made here to a two-dimensional or one-dimensional pattern. A pattern can thus include a homogeneous distribution of light over the entire flexible guide sheet. The pattern can also be a two-dimensional shape or symbol obtained by contrast between the light intensities of different positions in the X-Y plane of the flexible guide sheet 110. The pattern can also include several shapes or symbols. Alternatively, a pattern covers a predefined spatial distribution of the light intensity which does not reveal a general shape, such as a distribution inducing a cloud of light points.

In the embodiment of the , the light module 100 comprises a single source, a single injection element and a single flexible guide sheet.

There illustrates a three-dimensional view of equipment 20 comprising a light module 100 placed opposite a display module 1 according to the embodiments of Figures 1c and 1e, comprising a matrix of layers of electrochromic material 10.

The light module 100 is capable of projecting light rays, preferably broad-spectrum white light and homogeneously in the X-Y plane of the light module, in the direction of positive Z values towards the display module 1.

The layers of electrochromic material 10 of the display module 1 are capable of returning each of the light rays in the direction of the negative Z, the wavelength of the light rays depending on the thickness and properties of each layer of electrochromic material 10, and the electrical voltage applied to it, when the layers of electrochromic materials 10 are controlled by the control element 15.

According to other embodiments of the light module, described in the following, the light module may comprise at least two injection elements similar to the injection element 120 previously described. The embodiments may vary by the number of elements that the light module includes, and by their respective arrangements. However, the descriptions and definitions given previously of the light source, the injection element and the flexible guide sheet apply to all of the embodiments. In addition, the description of the also applies to an association between a display module 1 and a light module according to Figures 3 to 5.

There illustrates a light module 300 according to other embodiments of the invention.

Several injection elements are arranged so as to inject light into the same flexible guide sheet, comprising several patterns, forming a light guide 305 with several injection elements.

In particular, in the example of the , a first injection element 320.1 and a second injection element 320.2 are arranged so as to inject light into a light injection slice 314 of a flexible guide sheet 310.

The first and second injection elements 320.1 and 320.2 may be similar to the injection element 120 described with reference to Figures 2b and 2c. Likewise, the flexible guide sheet 310 can correspond to the flexible guide sheet 110 previously described. Thus, preferably, the injection elements 320.1 and 320.2 can form part of the flexible film of the sheet 110, and can be obtained by cutting and folding the flexible film, so as to form the light guide 305.

As shown on the , the first injection element 320.1 and the second injection element 320.2 are capable of injecting light into the light injection slice 314, at distinct longitudinal positions, along the Y axis.

Note that, due to its flexibility, the guide sheet 310 may not be flat but can be curved. There thus presents the light module 300 when the guide sheet is flat, for example placed on a rigid plane support.

The first injection element 320.1 is thus capable of injecting light into the light injection section 314, which is then guided by the flexible guide sheet 310 in a first part 315.1 of the flexible guide sheet 310. The second injection element 320.2 is capable of injecting light into the light injection edge 314, which is then guided in a second part 315.2 of the flexible guide sheet 310.

For this purpose, a first source 330.1 is arranged facing an entrance surface of the first injection element 320.1 so as to propagate light rays inside the first injection element 320.1 and therefore towards the first part 315.1 of the flexible guide sheet 310. A second source 330.2 is arranged opposite an entrance surface of the second injection element 320.2 so as to propagate light rays inside the second injection element 320.2 and therefore towards the second part 315.2 of the flexible guide sheet 310.

Alternatively, a single source can be provided and the light module 300 comprises a first optical fiber capable of routing the light from the single source towards the entrance surface of the first injection element 320.1 and a second optical fiber is capable of routing the light from the single source to the entrance surface of the second injection element 320.2.

The first and second sources 330.1 and 330.2, or the single source, can inject selectively into the first injection element 320.1 and/or into the second injection element 320.2. Such selective injection can be controlled by a control element 340 connected to the two sources 330.1 and 330.2, or controlling the supply of the two sources 330.1 and 330.2. Control element 340 may correspond to control element 15 previously described.

In the example of the , a first pattern comprising a first symbol 316.1 is engraved in the first part 315.1 while a second pattern comprising a second symbol 316.2 is engraved in the second part 315.2. However, the first part and the second part can be alternatively capable of emitting light in homogeneous patterns, with constant brightness over the entire first part 315.1 and the second part 315.2. The projection of symbols 316.1 and 316.2 is therefore optional.

The light module can be integrated into the external equipment 20 previously described so as to emit light on a display module 1 according to the invention.

For example, when the light module 300 is combined with the display module of the in external equipment 20, the layer of material 10.1 can be facing the first part 315.1 and the layer of material 10.2 can be facing the second part 315.2. It is thus made possible to display different colors, particularly at night or when the ambient light is weak, by selectively activating the sources of the light module 300. In addition, when patterns are engraved in the first and second parts 315.1 and 315.2 , it is made possible to display patterns of different colors on the exterior equipment 20.

The selective injection of light into the first injection element 320.1 and/or into the second injection element 320.2 thus makes it possible to project light onto a part of the lighting module 1 located opposite the first part 315.1, of the second part 315.2, or of both parts 315.1 and 315.2. It is thus made possible to perform an animation on the external equipment 20, to display different signaling patterns, to display different colors in different parts of the display module 1, or to control distinct display zones , for example as a function of data acquired by all of at least one sensor.

On the example of the , the first and second patterns 316.1 and 316.2 each correspond to a symbol, the symbols being distinct. However, in accordance with the definition of “pattern” previously given, the patterns can be any predetermined spatial distribution of light intensity, including in particular a homogeneous distribution of the light intensity. Furthermore, when the patterns are shapes or symbols, the first and second patterns may have identical shapes or symbols 316.1 and 316.2. An example with two injection elements has been shown on the . However, the embodiments of the also cover a light guide 305 with a flexible guide sheet with three or more parts and with at least three injection elements, each injection element being placed facing one of the parts.

Sources dedicated to each injection element can be provided for this purpose, or a single source with several optical fibers can be provided for this purpose.

There illustrates a light module 400 according to other embodiments of the invention.

In the embodiments of the , the light module 400 comprises at least a first light guide 405.1 with a first flexible guide sheet 410.1 and a second light guide 405.2 with a second flexible guide sheet 410.2, the two flexible guide sheets of the light guides 405.1 and 405.2 being superimposed, which implies that at least part of the first flexible guide sheet 410.1, in the XY plane, is superimposed with at least part of the second flexible guide sheet 410.2, in a common zone, which corresponds to a set of positions in the XY plane.

Preferably, the first and second flexible guide sheets 410.1 and 410.2 have the same dimensions in the X-Y plane, and completely overlap.

Note that due to their flexibility, the guide layers may not be flat but can be curved. There thus presents the light module 400 when the guide layers are flat, for example stacked on a flat support.

Such superposition is particularly advantageous due to the fact that the flexible guide sheets are transparent or semi-transparent as detailed previously.

par l’intensité lumineuse projetée vers le module d’affichage 1 lorsque les motifs projetés sont des motifs homogènes, comme décrits ci-après en référence aux sources de lumière; et/ou
par les symboles que comprennent les motifs projetés vers le module d’affichage 1, entre un premier symbole 416.1 et un deuxième symbole 416.2.

Thus, the first and second flexible guide sheets 410.1 and 410.2 are able to alternately project first and second light patterns in a common area. Projected patterns may differ:

by the light intensity projected towards the display module 1 when the projected patterns are homogeneous patterns, as described below with reference to the light sources; and or
by the symbols that comprise the patterns projected towards the display module 1, between a first symbol 416.1 and a second symbol 416.2.

A first injection element 420.1 of the first light guide 405.1 is capable of injecting light into a light injection slice of the first flexible guide sheet 410.1 and a second injection element 420.2 of the second light guide 405.2 is capable of injecting light into a light injection section of the second guide sheet 410.2.

For this purpose, a first source 430.1 of the light module 400 is arranged facing an entrance surface of the first injection element 420.1 so as to propagate light rays inside the first light guide 405.1 and therefore towards the first flexible guide sheet 410.1. A second source 430.2 of the light module 400 is arranged facing an entrance surface of the second injection element 420.2 so as to propagate light rays inside the second light guide 405.2 and therefore towards the second sheet of light. flexible guidance 410.2.

The first and second sources 430.1 and 430.2 can advantageously be capable of projecting light at different light intensities. It is thus made possible to control the light intensity projected on the display module 1.

The first and second sources 430.1 and 430.2 can inject selectively into the first injection element 420.1 and/or into the second injection element 420.2. Such selective injection can be controlled by a control element 440 connected to the two sources 430.1 and 430.2, or controlling the supply of the two sources 430.1 and 430.2, the control element 440 possibly being the control element 15 previously described.

When the flexible guide sheets comprise patterns comprising respective symbols, the first symbol 416.1 is engraved in the first flexible guide sheet 410.1 while the second symbol 416.2 is engraved in the second flexible guide sheet 410.2. The selective injection of light into the first injection element 420.1 and/or into the second injection element 420.2 thus makes it possible to project the first symbol, the second symbol, none of the symbols or both symbols at the same time, thus making possible, by dynamic control, the projection of distinct symbols on the display module 1.

When the flexible guide sheets include homogeneous patterns with different brightness levels, the first pattern may correspond to a first brightness level and the second pattern may correspond to a second brightness level, different from the first brightness level. Selective injection then makes it possible to illuminate the display module 1 according to the first brightness level, according to the second brightness level, or according to a sum of the first and second brightness levels.

An example with two light guides has been shown on the . However, the second embodiment also covers a light module with at least three light guides. Sources dedicated to each light guide can be provided for this purpose, with at least three levels of light intensity.

The flexible guide sheets are transparent or semi-transparent, as for the flexible guide sheets previously described.

There illustrates a light module 500 according to other embodiments of the invention.

In the embodiments of the , the light module 500 comprises at least a first light guide 505.1 and a second light guide 505.2, the two light guides being placed one next to the other, and the two light guides are thus capable of projecting light rays from distinct positions in the XY plane in which flexible guide sheets 510.1 and 510.2 respectively of the light guides 505.1 and 505.2 mainly extend.

Note that due to their flexibility, the flexible guide sheets may not be flat but can be curved. There thus presents the light module 500 when the flexible guide layers are flat, for example placed on a rigid flat support.

The light module 500 can be integrated into the external equipment 20 previously described so as to project light onto a display module 1 according to the invention.

Thus, the first flexible guide sheet 510.1 is able to illuminate in a first pattern, such as a homogeneous pattern, a first part of the display module 1 which faces it, and the second flexible guide sheet 510.2 is able to illuminate according to a second pattern, such as a homogeneous pattern, a part of the display module 1 which faces it. The same applies to each flexible guide sheet which projects light onto a given part of the display module 1.

In embodiments 1c and 1e, each part of a display module 1 may be one of the layers of electrochromic material 10 in the or a triplet of layers of electrochromic material in the . It is thus made possible to select the layers of electrochromic material 10, or triplets, which display a color, and those which are not illuminated and which therefore remain black in the absence of an external light source. Thus, the light module 500 can include as many light guides with flexible guide sheets as the display module 1 includes layers of electrochromic material 10 in the , or comprises triplets of layers of electrochromic material 10 in the . Alternatively, preferably, each flexible guide sheet illuminates several layers of electrochromic material 10 or triplets of layers of electrochromic material 10 of the display module 1. In particular, each flexible guide sheet can illuminate an entire pixel, such as described previously, the pixel comprising several tens or hundreds of layers of electrochromic material 10 or triplets of layers of electrochromic material 10. Still according to a preferred variant, each flexible guide sheet illuminates several pixels.

A first injection element 520.1 of the first light guide 505.1 is arranged to inject light into a light injection edge of the first flexible guide sheet 510.1 and a second injection element 520.2 of the second light guide 505.1 is arranged to inject light into a light injection section of the second guide sheet 510.2.

The manufacture of each light guide comprising an injection element and a flexible guide sheet conforms to the explanations previously given, and is not detailed again for the embodiments of the .

A first source 530.1 is arranged opposite an entrance surface of the first injection element 520.1 so as to propagate light rays inside the first light guide 505.1 and therefore towards the first flexible guide sheet 510.1. A second source 530.2 is arranged opposite an entrance surface of the second injection element 520.2 so as to propagate light rays inside the second light guide 505.2 and therefore towards the second flexible guide sheet 510.2.

Alternatively, a single source can be provided and the light module 500 comprises a first optical fiber capable of routing the light from the single source towards the entrance surface of the first injection element 520.1 and a second optical fiber is capable of routing the light from the single source to the entrance surface of the second injection element 520.2.

The first and second sources 530.1 and 530.2, or the single source, can selectively inject light into the first injection element 520.1 and/or into the second injection element 520.2. Such selective injection can be controlled by a control element 540 connected to the two sources 530.1 and 530.2, or controlling the supply of the two sources 530.1 and 530.2.

The selective injection of light into the first injection element 520.1 and/or into the second injection element 520.2 thus makes it possible to project light in a pattern, by one or the other, or both, layers flexible guides 510.1 and 510.2. The same applies to other flexible guide layers of other light guides which are not numbered on the .

In the example of the , a light module 500 comprising twelve light guides with flexible guide sheet and twelve light sources, arranged in a matrix with three rows and four columns, has been shown, for illustration purposes only.

No restriction is attached to the number of light guides in these embodiments. The embodiments of the thus apply to N light guides and N light sources, or a single source connected by N optical fibers to the N injection elements of the N light guides, N being any integer greater than or equal to 2.

No restriction is also attached to the arrangement of the flexible guide layers in relation to each other. When positioned in matrices, there are no restrictions attached to the number of rows or the number of columns.

The first and second patterns may be distinct symbols, and may for example be identical to symbols 316.1 and 316.2 of the . However, preferably, the patterns can be homogeneous distributions of light on each flexible guide sheet.

In addition, as explained previously, the patterns may comprise parts of symbols complementary to each other, so as to form one or more symbols on several flexible guide sheets of the matrix.

The light guides can be linked to each other by a support matrix structure, which can itself be flexible. Alternatively, each light guide can be connected to the light guides which surround it by fixing means, by gluing, clamping, clipping, or any other method.

All of the light sources can be controlled by the control element 540, via a set of wires, each wire connecting the control element 540 to a light source. The control element 540 can be the control element 15 previously described. The wires can be carried by a 550 structure making it possible to centralize the wires and route them to the control element, which reduces the bulk, and also makes it possible to hide the wires.

une dimension comprise entre 2cm et 10cm, par exemple entre 2cm et 5cm, par exemple égale à 5cm; et
une autre dimension comprise entre 2cm et 10cm, par exemple entre 2cm et 5cm, par exemple égale à 5cm.

No restriction is attached to the dimensions in the XY plane of the flexible guide layers. For example, each flexible guide sheet can be rectangular or square in shape, with at least one dimension between 2 and 10 cm. For example, flexible guide sheets are squares or rectangles, with:

a dimension between 2cm and 10cm, for example between 2cm and 5cm, for example equal to 5cm; And
another dimension between 2cm and 10cm, for example between 2cm and 5cm, for example equal to 5cm.

For example, each flexible guide sheet is a square of 3cm by 3cm.

In this case, each flexible guide sheet is capable of illuminating several pixels of the display module 1 according to the or according to the . Alternatively, each flexible guide sheet has the same size as a single pixel, for example a square of 1mm by 1mm or 3mm by 3mm.

The control elements 15, 340, 440 and 540 may include a processor configured to communicate unidirectionally or bidirectionally, via one or more buses or via a wired connection, with a memory such as a “Random Access Memory” type memory. , RAM, or a “Read Only Memory” type memory, ROM, or any other type of memory (Flash, EEPROM, etc.). Alternatively, the memory comprises several memories of the aforementioned types. Preferably, the memory is a non-volatile memory. The processor is able to execute instructions, stored in the memory, for the implementation of one or more animations depending on the reception of animation commands. Alternatively, the processor can be replaced by a microcontroller designed and configured to implement one or more animations based on receiving animation commands.

The present invention is not limited to the embodiments described above by way of examples; it extends to other variants.

Claims

Exterior equipment (20) for a motor vehicle (30), said exterior equipment comprising a display module (1), said display module comprising:

at least one layer of electrochromic material (10) having a first surface (13), said layer of electrochromic material being capable of receiving light rays incident by said first surface (13) and of returning light rays among the light rays incident from said first surface;

a metal mirror (11) arranged on a second surface of said electrochromic material layer;

characterized in that said layer of electrochromic material is configured to form a Fabry-Pérot cavity so that said returned light rays have a wavelength included in an interval defined at least by properties of the electrochromic material of said layer and/or by a thickness of said layer of electrochromic material.
Outdoor equipment according to claim 1, in which the electrochromic material (10) belongs to the family of organic transparent conductive oxide materials, in particular a transparent conductive polymer of the PEDOT:PSS, PEDOT:tos, PMMA, T34bT or cellulose type.
External equipment according to claim 1, further comprising a control element (15) capable of controlling an electrical voltage applied to the display module (1) so as to vary said properties of the electrochromic material of the layer and/or the thickness of the layer of electrochromic material.
Outdoor equipment according to claim 3, comprising a set of at least one sensor (16), in which the control element (15) is capable of receiving data from the set of at least one sensor (16), and in which the control element is able to control the electrical voltage applied to the display module (1) as a function of the data from all of at least one sensor.
Outdoor equipment according to claim 4, in which the assembly comprises at least one ambient light sensor (16).
External equipment according to one of the preceding claims, in which the display module (1) comprises several layers of electrochromic material (10.1; 10.2; 10.11; 10.12; 10.13; 10.21; 10.22; 10.23; 10.31; 10.32; 10.33) arranged next to each other in a line or array, in which at least two layers of electrochromic material have different thicknesses.
External equipment according to one of claims 4 to 6, in which the display module (1) comprises a layer of electrolyte associated with each layer of electrochromic material, and in which the control element (15) is capable of control voltages respectively applied to the electrolyte layers so as to vary the thickness and/or properties of the layers of electrochromic material (10.11; 10.12; 10.13; 10.21; 10.22; 10.23; 10.31; 10.32; 10.33) independently of each other others, so as to dynamically vary an image displayed by the display module (1).
Exterior equipment according to one of claims 1 to 7, in which the exterior equipment (20) is a vehicle body element (30).
Outdoor equipment according to one of the preceding claims, in which the display module (1) is included between a surface (22) of the outdoor equipment (20) and a covering element (21).
External equipment according to one of the preceding claims, further comprising a transparent light module (100; 300; 400; 500) arranged facing the first surface (13) of the display module (1) so as to illuminate said at minus a layer of electrochromic material (10).
Outdoor equipment according to claim 5 and claim 10, in which the control element (15; 340; 440; 540) is capable of activating at least one light source (130; 330.1; 330.2; 430.1; 430.2; 530; 530.2) of the light module (100; 300; 400; 500) when an ambient brightness measurement is below a given threshold.
Outdoor equipment according to claim 10 or 11, in which the transparent light module (100; 300; 400; 500) comprises:
at least one light guide (105; 305; 405.1; 405.2; 505.1; 505.2), said light guide comprising a flexible guide sheet (110; 310; 410.1; 410.2; 510.1; 510.2) transparent or semi-transparent, the flexible guide sheet being capable of receiving light rays through at least one light injection edge (114; 314) of said flexible guide sheet and of returning the light rays in a direction substantially normal to a surface of the sheet of flexible guidance;
at least one light source (130; 330.1; 330.2; 430.1; 430.2; 530; 530.2) capable of injecting light into said light guide.
Outdoor equipment according to claim 12, in which said light guide comprises at least one light injection element (120; 320.1; 320.2; 420.1; 420.2; 520.1; 520.2) capable of receiving light from said light source and to distribute the light in said flexible guide sheet (110; 310; 410.1; 410.2; 510.1; 510.2).
Outdoor equipment according to claim 13, in which the light module (100; 300; 400; 500) comprises two light guides (505.1; 505.2) placed next to each other so as to form a matrix of light guides, and each flexible guide sheet of each light guide (510.1; 510.2) being arranged facing at least one layer of electrochromic material of the display module (1).
Outdoor equipment according to one of claims 12 to 13, in which the flexible guide sheet (110; 310; 410.1; 410.2; 510.1; 510.2) of each light guide comprises a film (111) comprising etched microstructures (113). by ultraviolet printing so as to reflect the light injected into the light guide according to a given pattern.
Motor vehicle (30) comprising external equipment according to one of the preceding claims.