FR3143719A1 - Interior equipment with a display module with a layer of electrochromic material - Google Patents

Abstract

The invention relates to interior equipment (20) for a motor vehicle, said interior equipment comprising a display module (1). The display module comprises at least one layer of electrochromic material (10), said layer of electrochromic material being capable of receiving light rays incident by a first surface (13) and of returning light rays among the light rays incident from the first surface, said returned light rays having a wavelength included in an interval defined at least by properties of the material of said layer and by a thickness of the layer of electrochromic material. The display module further comprises a metal mirror (11) arranged on a second surface of the material layer. FIG. 1a

Description

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

The present invention relates to the field of interior equipment for motor vehicles, in particular interior equipment having information display 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, in order to display information, for aesthetic purposes of personalization or to create ambiance.

To do this, 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.

Furthermore, it is preferable to have a flexible and lightweight display or lighting module in order to facilitate its integration into any type of equipment. This is particularly the case inside a motor vehicle, in which the equipment, such as the dashboard, doors or seats, have non-flat surfaces.

Furthermore, the above solution has the disadvantage of high energy consumption, which is all the more important as the surface area of the equipment in which one wishes to integrate a display module is large.

Finally, the aforementioned display module has the disadvantage of being difficult to read in sunny weather or when interior lighting sources are powerful, the contrast with the ambient light being too low.

There is therefore a need for interior equipment for a motor vehicle comprising a display module that is lightweight, robust, inexpensive, consumes little energy, is easy to integrate and has good visibility during the day, particularly when the ambient light has a high luminous intensity.

The present invention improves the situation.

• au moins une couche de matériau électrochrome, ladite couche de matériau électrochrome étant apte à recevoir des rayons lumineux incidents par une première surface et à renvoyer des rayons lumineux parmi les rayons lumineux incidents depuis la première surface, lesdits rayons lumineux renvoyés ayant une longueur d’onde comprise dans un intervalle défini au moins par des propriétés du matériau électrochrome et par une épaisseur de la couche de matériau;
• un miroir métallique agencé sur une deuxième surface de la couche de matériau.

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

• at least one layer of electrochromic material, said layer of electrochromic material being capable of receiving light rays incident through a first surface and of returning light rays among the light rays incident from the first surface, said returned light rays having a wavelength included in an interval defined at least by properties of the electrochromic material and by a thickness of the layer of material;
• a metal mirror arranged on a second surface of the material layer.

The use of an electrochromic material makes it possible to form a Fabry-Pérot type cavity, and thus makes it possible to display a given color on the display module. Indeed, this cavity produces, from the light it receives, interferences of a determined wavelength. These interferences result in multiple reflections of colored rays propagating inside the cavity. Thus, it is by an interference phenomenon, 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 the ambient light is high, no energy consumption is required to display such a structural color, the material layer being able to operate passively. The display module therefore allows considerable energy savings compared to the 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 in thickness or between 50 and 800 nm, for example between 75 and 300 nm, and therefore both compact and lightweight. Since the display function is structurally linked to the electrochromic material layer, the display module is also very robust, in particular to mechanical shocks and temperature variations. A Fabry-Pérot cavity can reflect approximately between 60% and 90% of the incident light intensity, which allows good visibility of the display module in sunny weather.

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 term “transparent conductive oxide”), in particular a transparent conductive polymer of the PEDOT:PSS, PEDOT:tos, PMMA, T34bT or cellulose type.

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 from alloys of at least two of these three metals.

In one embodiment, the interior 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 such that under electrical stimulation, for example when applying an electrical voltage to the electrolyte layer, the ions of the electrolyte layer migrate into the layer of electrochromic material. The quantity of the “migrating” ions depends on the value of the electrical quantity applied. The more numerous the “migrating” ions, 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 the properties of this layer. Thus, the layer of electrochromic material is electrochemically adjustable.

It is thus made possible to display a color with a dynamic variation of the color or of the luminous 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 induces a low energy consumption.

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

In practice, the electrolyte layer is connected to at least two electrodes, for example a working electrode and an electrode system comprising a counter electrode and a reference electrode.

Additionally, the control element may be capable of receiving data from a set of at least one sensor, and the control element may be capable of controlling the electrical stimulus applied to the display module based on the data from the set of at least one sensor.

This makes it possible to adapt the color(s) displayed to the vehicle's environment, when the sensor is able to capture vehicle environment data, or based on data captured inside the vehicle's passenger compartment (presence of passengers, interior temperature, brightness inside the vehicle, etc.).

In addition, the unit can 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 depending on the ambient brightness, which improves the visibility of the display module.

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

This makes it possible to create 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.

In addition, the display module may comprise at least one triplet of layers of electrochromic material, each triplet of electrochromic layers comprising a first layer of electrochromic material of a first thickness, a second layer of electrochromic material of a second thickness, and a third layer of electrochromic material of a third thickness, the first, second and third thicknesses may be different, said first, second and third thicknesses being defined so that, upon application of respective electrical voltages to the first, second and third layers of electrochromic material, the light rays returned by the first, second and third layers of electrochromic material form a beam of white light.

Thus, it is made possible to display white light. For this purpose, each layer of a triplet preferably has a dimension smaller than a value defined by the resolving capacity of the human eye. Thus, the light rays from the three layers of the triplet are synthesized by the human eye so as to see white light.

Alternatively or additionally, the display module may comprise an electrolyte layer associated with each layer of electrochromic material. In this case, the control element may be capable of controlling 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.

This makes it possible to vary a pattern, an image, the color of an image and/or its light intensity. Such a variation can be used to signal information or fulfill an aesthetic function.

Additionally, the display module may include a matrix of triplets of electrochromic material layers, and the control element may be capable of controlling each triplet of electrochromic material layers independently.

The layers of material in each triplet may have thicknesses such that, when no voltage is applied to them, the triplet of layers of electrochromic material is black, for example because each triplet reflects only rays of wavelengths outside the visible range, and when respective electrical voltages are applied to the layers of the triplet, red light, green light and blue light is reflected from the triplet of layers so as to constitute a beam of white light.

It is thus possible to produce a black and white screen by controlling the voltage of the triplets of layers of electrochromic material forming a matrix, each triplet of layers of electrochromic material constituting a black or white pixel of this screen.

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 interior equipment may be a dashboard.

Integrating display functions into the dashboard is advantageous both for communicating with the driver or passenger, but also for achieving aesthetic or ambient functions.

Alternatively, the interior equipment may be a door or a roof of a motor vehicle.

This makes it possible to create lighting functions to create an atmosphere inside the motor vehicle.

Alternatively, the interior equipment can be a motor vehicle seat.

This makes it possible to display information for passengers in the rear of the vehicle, or to create a lighting atmosphere at the rear of the vehicle.

According to embodiments, the display module may be comprised between a surface of the interior equipment and a cover element.

The cover 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, which improves its durability. In addition, the cover element can protect the display module against UV radiation.

According to embodiments, the interior 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.

This makes it possible to display the structural color(s) of the display module regardless of the ambient brightness.

Additionally, the control element may be capable of activating at least one light source of the light module when an ambient brightness measurement is below a given threshold.

This optimises the activation of the light module, as it is only switched on when the ambient light inside the vehicle is too low. This optimises the energy consumption of the interior equipment.

• 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 et au moins un élément d’injection de lumière apte à recevoir de la lumière et à distribuer la lumière dans la nappe de guidage flexible ;
• au moins une source de lumière apte à injecter de la lumière dans ledit au moins un élément d’injection de lumière.

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

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

This makes it 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 above example, the guide sheet may comprise return elements for reflecting light rays towards said at least one layer of electrochromic material in order to illuminate it. The return elements may be microstructures, prisms, or suspended particles integrated into the guide sheet. Advantageously, the return elements are arranged on or as close as possible to the face of the guide sheet which is adjacent to said at least one layer of electrochromic material.

Additionally, the light module may comprise 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 opposite at least one layer of electrochromic material of the display module.

This makes it possible to selectively illuminate several parts of the display module.

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

Such 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. In particular, it is 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 and 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.

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

Additionally, 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.

This makes it possible to return light in a homogeneous manner.

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

According to embodiments, each injection element may comprise a plurality of injection sheets, each injection sheet 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 sheets all being different so as to distribute the light longitudinally in the injection element.

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

Another subject of the invention relates to a motor vehicle comprising interior equipment presented previously.

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

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

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

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

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

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

illustrates a structure of an interior equipment according to embodiments of the invention;

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

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

illustrates a light module of an interior equipment for a motor vehicle according to an embodiment of the invention;

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

illustrates an interior equipment for a motor vehicle according to an embodiment of the invention;

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

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

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

The description focuses on the features that distinguish the interior equipment and the light module from those known in the state of the art.

There shows 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. By electrochromic is meant a material that changes color when an electrical voltage is applied to it for a short 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 exit the layer of electrochromic material depending on the value of the electrical quantity applied. These specific wavelengths correspond to a color in the visible spectrum and reach the eyes of an observer. The latter therefore has the impression that the layer of material has changed color. The material retains the new color as long as the 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 via the surface 13 and then interferes with the electrochromic material 10. The interference phenomenon leads to the electrochromic material 10 returning light rays via 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 metal mirror 11 used. The metal mirror 11 can for example be made of chrome, aluminum or gold.

The layers 10 and 11 can be attached to a substrate 12. No restriction is attached to the material of the substrate. Preferably, the layers 10, 11 and 12 are thin enough for the display module 1 to be flexible. The display module 1 can in particular have a thickness of the order of 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, or poly(3,4-ethylenedioxythiophene), or PEDOT:Tosylate type polymer. 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, i.e. of a given color defined by the thickness of the layer, or colorless, i.e. black, in a resting state, flexible, the electro-optical properties to form a Fabry-Perot cavity in an excited state. In addition, 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 denotes poly(3,4 ethylenedioxythiophene): sodium poly(styrene sulfonate);
PEDOT:Tos denotes poly(3,4 ethylenedioxythiophene):Tosylate;
PMMA means PolyMethyl MethAcrylate;
T34bT denotes 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 may for example be ambient light, such as sunlight or 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 lumens, the electrochromic material returns a luminous flux of between 240 and 360 lumens.

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

Further details on such a display module 1, as well as on how to choose a color from the UV treatment that is applied to the electrochromic material 10, the intensity of the treatment and its duration in particular, depending on the electrochromic material and depending on the metal layer 11, 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.

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 may 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 in 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 between the counter electrode and the material layer 10. 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, the encapsulation can be carried out by dip-coating , followed by crosslinking by UV irradiation. No restriction is attached to the composition or dosage of the electrolytic solution. It can for example be a 0.1M solution of sodium dodecylbenzenesulfonate NaDBS in water.

Applying a voltage to the display module 1 makes it possible to both modify the thickness of the layer of electrochromic material 10 and also to oxidize or reduce it, and thus change the nano-optical properties of the 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 returned light.

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, which may be a sensor able to obtain environmental data from the vehicle, or a sensor located inside the passenger compartment, able to measure an interior temperature, to detect a driver and/or a passenger, to measure ambient brightness. Depending on the data captured, the control element 15 may vary the light intensity and/or the color emitted by the layer of electrochromic material 10, by controlling the voltage applied to it.

The sensor 16 may for example be capable of acquiring measurements of ambient light intensity inside the vehicle. The control element can then control the electrical voltage to be applied as a function of the ambient light intensity.

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

There shows a display module 1 according to other embodiments of the invention. Compared to the display module 1 shown in 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.

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

The layers of material 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 may be capable of reflecting light in the same color, or in distinct colors. In particular, the layers of materials 10.1 and 10.2 may have distinct thicknesses, at rest, when no voltage is applied to them.

There are no restrictions on 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 X axis. Alternatively, they may be distributed at distinct positions along the Y axis. The display module 1 may comprise more than three layers placed 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 controlled together, that is to say that 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 capable of passively returning light according to 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:

• varying the light intensity and/or the colour of a predefined image by the respective colours and the respective arrangement of the layers of electrochromic material 10; and/or
• differentially control the layers of electrochromic material so as to dynamically vary the displayed pattern or 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.

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, this is the first layer of electrochromic material 10.11. The first voltage may 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, this is the second layer of electrochromic material 10.12. The second voltage may 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, this is the third layer of electrochromic material 10.13. The third voltage may be equal to 0.9V.

Advantageously, the three layers of electrochromic material 10.11, 10.12 and 10.13 may be such that they do not return any wavelength in the visible spectrum when no voltage is applied to them.

The width, or X-axis dimension, of each of the electrochromic material layers 10.11, 10.12 and 10.13 is small enough to be below the resolution of the human eye. Thus, an observer cannot separate the light emitted therefrom and the rays emitted from the three electrochromic material layers 10.21, 10.22 and 10.23 combine to form a white light beam. For example, the X-axis dimension of a layer may 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. The control of the display of a white or black surface can depend on sensor data received from the set of at least one sensor 16, as previously explained for the other embodiments.

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

In these embodiments, the display module 1 comprises several triplets of layers of electrochromic material 10 presented with reference to the . Each triplet of electrochromic material layers may be similar to the triplet of electrochromic material layers 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 triple layers of electrochromic material 10 placed next to each 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 may be arranged on the same metal mirror 11 or on respective metal mirrors 11. Similarly, the triplets of layers of electrochromic material 10 on respective metal mirrors 11 may be arranged on the same substrate 12 or on respective substrates 12.

It is thus advantageously possible to display white light at several positions in X of the display module 1. As a variant, the triplets of layers of electrochromic material are distributed at several positions in Y. As a further variant, the triplets of 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. As a variant, 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 may thus comprise several hundred triplets of layers of electrochromic material 10. Each pixel comprises triplets of layers of electrochromic material which are thus driven 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 the second layers of electrochromic material 10.21, 10.22 and 10.23 and identical electrical voltages are applied to all the third layers of electrochromic material 10.31, 10.32 and 10.33, so that the whole of a pixel is black or white. The voltages can be driven by the control element 15, as for the embodiments of the . Here, by applying the electrical voltage to the layer of electrochromic material, we mean applying the electrical 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, the control of the voltages applied to the layers of electrochromic material 10 makes it possible to display a white or black pixel at each pixel. Each pixel is thus driven independently of the other pixels. 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 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.

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

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

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

The interior 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 may be that described with reference to the ,1b, 1c, 1d or 1e. Thus, the interior 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 may be external to the interior equipment 20.

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

No restrictions are attached to the manner in which the display module 1 is mounted or secured to the surface 22 or to the structure of the interior equipment 20.

The interior equipment 20 may further comprise a cover element 21 arranged on the display module 1, which is thus comprised between the cover element 21 and the surface 22. The cover element 21 may for example be a protective film having the same dimensions as the display module 1. Alternatively, the cover element 21 may 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 for the display module 1. It can also provide a UV protection function.

No restriction is attached to the interior equipment 20 of a motor vehicle, which may be a dashboard for example. Thus, when the light module 1 is according to the or the , it is made possible to display information for the driver and/or passenger. Alternatively, the interior equipment 20 may be a roof or a door, in which case the surface 22 is an interior surface of the door or an interior surface of the roof (or the ceiling of the vehicle passenger compartment). It is thus made possible to create a lighting ambiance inside the vehicle. Still alternatively, the interior equipment 20 is a vehicle seat, in particular the front seats of a vehicle, and the surface 22 and the rear surface of the seat, so as to be able to display information for the passengers at the rear of the vehicle, or to create a lighting ambiance at the rear of the vehicle.

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

Compared to the structure of the interior equipment 20 presented with reference to the , the interior 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 the light rays emitted by the layer of material 10 of the display module 1 to be emitted towards the exterior of the interior equipment 20.

It is thus possible to illuminate the display module 1, in particular when the ambient light, sunlight or artificial light, 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 not 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 switching on 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 in the figure. . Alternatively, the control element 15 is capable of receiving ambient brightness measurements from the set 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, according to a homogeneous pattern or presenting spatial variations in light intensity.

No restriction is 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 a light injection element into the sheet, as described in the following.

There presents a light guide 105 of a light module of an interior 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 via 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 thus extends in an XY plane on the .

A guide sheet is understood to mean an optical guide element of which one of the dimensions is much smaller than the other two dimensions in space, for example one or more orders of magnitude smaller. As illustrated in 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 XY plane in which the flexible guide sheet 110 extends.

The flexible guide sheet 110 may comprise a flexible film 111 at its core comprising the light injection edge 114, being capable of guiding the light rays in a global direction X, and comprising a set of microstructures 113 capable of returning the light rays 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 may 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, combined with a low thickness as described above, make it possible to obtain a flexible and transparent film 111. Other materials may be provided for the composition of the flexible film 111. However, it is preferable according to the invention to provide deformable and transparent materials.

A thin coating of microstructures 113 may be applied to one of the faces of the flexible film 111, or be integrated into the flexible film 111. The coating of microstructures 113 may 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 exiting the flexible film 111 to form a pattern. For this purpose, the microstructures 113 may 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 homogeneous light over the entire surface of the flexible film 111. This is then referred to as a homogeneous pattern in the following.

Microstructures 113 are understood to mean structures, or irregularities of the flexible film, whose dimensions are less than a few micrometers. The 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. Alternatively, the flexible guide sheet 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 X axis so that a linear density of microstructures 113 is proportional to the distance from the light injection edge 114 through which the light rays injected by an injection element 120 are received. In other words, the further the microstructures 113 are from the light injection edge 114, the more densely they are grouped. 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 comprise an anti-UV treatment, 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, in particular when exposed to sunlight.

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 may be attached to the flexible film, in particular by lamination.

The propagation of light rays in the flexible film 111 is done by total internal reflection thanks to the difference between the refractive index of the flexible film 111 and that of 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. Specifically, a layer of glue is located between the flexible film 111 and each protective layer 112.1 and 112.2, and this on both sides of the flexible film to adhere the protective layers to the flexible film.

The selected glue 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, due to the difference in refractive index, the light rays propagating in the flexible film undergo total reflection when they encounter 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 able to guide light by total internal reflection of this light, for example from an entry zone, here the injection edge 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 105 light guide illustrated on the also comprises a light injection element 120, comprising a set of injection sheets described with reference to FIGS. 2b and 2c, the light injection element being capable of distributing the light in the flexible guide sheet 110 at 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 entry surface 121 of rectangular or square section on the . However, the light injection element 120 may have an entry surface having a different shaped section.

On the , the light injection element 120 is shown with an output surface 122 extending in the Y direction and placed opposite the light injection edge 114. It will be understood from reading the description of FIGS. 2b and 2c that the output surface 122 and the light injection edge 114 are merged, the flexible film 111 and the set of injection sheets forming a single piece.

The light injection element 120 further comprises the input 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 in the figure. , and the light injection element 120 is capable of guiding the light longitudinally along the Y axis by distributing it on the output surface 122. The distribution of light by the output surface 122 will be better understood in light of the description of FIGS. 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 sheets 123.1, 123.2 and 123.3 capable of receiving light from the source 130 via the entry surface 121 and of guiding the light to distinct sets of positions along the Y axis 124.1, 124.2 and 124.3. As shown in FIGS. 2b and 2c, the injection sheets 123.1, 123.2 and 123.3 may be made of the same material and have the same thickness as the flexible film 111 of the guide sheet 110. Thus, the light guide 105 may be obtained by a roll-to-roll, or R2R, manufacturing procedure, during which the flexible film 111 and the injection sheets 123.1, 123.2 and 123.3 are obtained from the same roll of flexible film, the injection sheets 123.1, 123.2 and 123.3 being cut at different Y positions, in a cutting direction substantially parallel to the X direction. The injection sheets thus obtained are flexible and can be folded as shown in FIG. . 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 FIGS. 2b and 2c, for illustrative purposes only. The injection element 120 may however comprise any set of injection layers comprising at least two injection layers.

No restriction is attached to the light source 130. The light source 130 may be capable of generating light in a range of wavelengths. Such an interval may be centered around a visible color, in order to generate colored light, for example blue, red or green. Alternatively, and preferentially according to the invention, the light source 130 may 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 a broad spectrum light onto the display module 1 described above.

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 opposite the entry 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 of a source 130 thus makes it possible to project light in the Z direction by a flexible, transparent or semi-transparent surface, with good surface homogeneity and according to a given pattern.

In practice, such a light module can 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.

“Pattern” means any predefined spatial distribution or 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 may thus comprise a homogeneous distribution of light over the entire flexible guide sheet. The pattern may 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 may also comprise several shapes or symbols. Alternatively, a pattern covers a predefined spatial distribution of the light intensity not showing 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 FIGS. 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 the properties of each layer of electrochromic material 10, and on 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 in the number of elements that the light module comprises, and in their respective arrangements. However, the descriptions and definitions given above 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 a single 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 FIGS. 2b and 2c. Similarly, the flexible guide sheet 310 may correspond to the flexible guide sheet 110 previously described. Thus, preferably, the injection elements 320.1 and 320.2 may be part of the flexible film of the sheet 110, and may be obtained by cutting and folding the flexible film, so as to form the light guide 305.

As shown in 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 may be curved. thus presents the light module 300 when the guide sheet is flat, for example placed on a flat rigid support.

The first injection element 320.1 is thus able to inject light into the light injection slice 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 able to inject light into the light injection slice 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 entry 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 facing an entry 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 may be provided and the light module 300 comprises a first optical fiber capable of conveying light from the single source to the input surface of the first injection element 320.1 and a second optical fiber capable of conveying light from the single source to the input surface of the second injection element 320.2.

The first and second sources 330.1 and 330.2, or the single source, may selectively inject into the first injection element 320.1 and/or into the second injection element 320.2. Such selective injection may 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. The control element 340 may correspond to the control element 15 previously described.

In the example of the , a first pattern comprising a first symbol 316.1 is etched in the first portion 315.1 while a second pattern comprising a second symbol 316.2 is etched in the second portion 315.2. However, the first portion and the second portion may be alternately capable of emitting light in homogeneous patterns, with constant brightness across the entire first portion 315.1 and second portion 315.2. The projection of symbols 316.1 and 316.2 is thus optional.

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

For example, when the light module 300 is combined with the display module of the in an interior equipment 20, the material layer 10.1 may be facing the first part 315.1 and the material layer 10.2 may be facing the second part 315.2. It is thus made possible to display different colors, in particular at night or when the ambient light is low, by selectively activating the sources of the light module 300. Furthermore, 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 interior 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 portion of the lighting module 1 located opposite the first portion 315.1, the second portion 315.2, or both portions 315.1 and 315.2. It is thus made possible to produce an animation on the interior equipment 20, to display different colors in different portions of the display module 1, or to control distinct display areas, for example based on data acquired by the set 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 may be any predetermined spatial distribution of light intensity, including in particular a homogeneous distribution of 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 in 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 opposite one of the parts.

Dedicated sources for 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 a portion of the first flexible guide sheet 410.1, in the XY plane, is superimposed with at least a portion of the second flexible guide sheet 410.2, in a common area, 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 sheets may not be flat but may be curved. thus presents the light module 400 when the guide sheets are flat, for example stacked on a flat support.

Such superposition is particularly advantageous because the flexible guide sheets are transparent or semi-transparent as detailed above.

• 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 capable of alternately projecting first and second light patterns in a common area. The 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 which 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 slice of the second guide sheet 410.2.

For this purpose, a first source 430.1 of the light module 400 is arranged opposite an entry 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 opposite an entry 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 flexible guide sheet 410.2.

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

The first and second sources 430.1 and 430.2 can selectively inject 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 being able to be the control element 15 previously described.

When the flexible guide sheets comprise patterns comprising respective symbols, the first symbol 416.1 is etched in the first flexible guide sheet 410.1 while the second symbol 416.2 is etched 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 it possible, by dynamic control, to project distinct symbols onto the display module 1.

When the flexible guide sheets comprise 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. The 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 in the . However, the second embodiment also covers a light module with at least three light guides. Dedicated sources for each light guide may be provided for this purpose, with at least three levels of light intensity.

The flexible guide sheets are transparent or semi-transparent, as with 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 next to each other, and the two light guides are thus able to project light rays from distinct positions in the XY plane in which respective flexible guide sheets 510.1 and 510.2 of the light guides 505.1 and 505.2 mainly extend.

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

The light module 500 can be integrated into the interior 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 according to 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 electrochromic material layers 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 comprise as many light guides with a flexible guide sheet as the display module 1 comprises 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, as described previously, the pixel comprising several tens or hundreds of layers of electrochromic material 10 or triplets of layers of electrochromic material 10. Again 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 slice 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 slice of the second guide sheet 510.2.

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

A first source 530.1 is arranged facing an entry 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 facing an entry 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 may be provided and the light module 500 comprises a first optical fiber capable of conveying light from the single source to the input surface of the first injection element 520.1 and a second optical fiber capable of conveying light from the single source to the input surface of the second injection element 520.2.

The first and second sources 530.1 and 530.2, or the single source, may selectively inject light into the first injection element 520.1 and/or into the second injection element 520.2. Such selective injection may be controlled by a control element 540 connected to both sources 530.1 and 530.2, or controlling the power supply of both 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 according to a pattern, by one or the other, or both, flexible guide sheets 510.1 and 510.2. The same applies to the other flexible guide sheets of the other light guides which are not numbered on the .

In the example of the , a light module 500 comprising twelve flexible guide sheet light guides and twelve light sources, arranged in a three-row, four-column matrix, has been shown, for illustrative 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.

There are also no restrictions on the arrangement of the flexible guide sheets relative to each other. When they are positioned in matrices, there are no restrictions on 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 may be homogeneous distributions of light on each flexible guide sheet.

Further, as explained above, the patterns may include portions of symbols that are complementary to each other, so as to form one or more symbols on multiple flexible guide webs of the matrix.

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

The set of light sources may 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 may be the control element 15 previously described. The wires may be carried by a structure 550 for centralizing the wires and routing them to the control element, thereby reducing bulk, and also for hiding 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.

There are no restrictions on the dimensions in the XY plane of the flexible guide webs. For example, each flexible guide web may be rectangular or square in shape, with at least one dimension between 2 and 10 cm. For example, the flexible guide webs 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 3cm by 3cm square.

In this case, each flexible guide sheet is able to illuminate 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 1mm by 1mm or 3mm by 3mm square.

The control elements 15, 340, 440 and 540 may comprise a processor configured to communicate in a one-way or two-way manner, 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 capable of executing instructions, stored in the memory, for the implementation of one or more animations according to the reception of animation commands. Alternatively, the processor may be replaced by a microcontroller designed and configured for the implementation of one or more animations according to the reception of animation commands.

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

Claims (23)

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

• at least one layer of electrochromic material (10), said layer of electrochromic material being capable of receiving light rays incident via a first surface (13) and of returning light rays among the light rays incident from the first surface, said returned light rays having a wavelength included in an interval defined at least by properties of the electrochromic material of said layer and by a thickness of the layer of electrochromic material;
• a metal mirror (11) arranged on a second surface of the electrochromic material layer.

Interior 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. Interior 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. Interior equipment according to claim 3, comprising a set of at least one sensor (16), wherein the control element (15) is capable of receiving data from the set of at least one sensor (16), and wherein the control element is capable of controlling the electrical voltage applied to the display module (1) as a function of the data from the set of at least one sensor. Interior equipment according to claim 4, in which the assembly comprises at least one ambient light sensor (16). Interior equipment according to one of the preceding claims, wherein 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 in a matrix, in which at least two layers of electrochromic material have different thicknesses. Interior equipment according to claim 6, wherein the display module (1) comprises at least one triplet of layers of electrochromic material, each triplet of electrochromic layers (10.11; 10.12; 10.13; 10.21; 10.22; 10.23; 10.31; 10.32; 10.33) comprising a first layer of electrochromic material (10.11; 10.12; 10.13) of a first thickness, a second layer of electrochromic material (10.21; 10.22; 10.23) of a second thickness, and a third layer of electrochromic material (10.31; 10.32; 10.33) of a third thickness, wherein the first, second and third thicknesses are different, said first, second and third thicknesses being defined by such that, upon application of respective electrical voltages to the first, second and third layers of electrochromic material, the light rays returned by the first, second and third layers of electrochromic material form a beam of white light. Interior equipment according to claim 4 or 5 and according to claim 6 or 7, wherein the display module (1) comprises an electrolyte layer associated with each layer of electrochromic material, and wherein the control element (15) is capable of controlling voltages respectively applied to the electrolyte layers so as to vary the thickness and/or the 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, so as to dynamically vary an image displayed by the display module (1). Interior equipment according to claims 7 and 8, wherein the display module (1) comprises a matrix of triplets of layers of electrochromic material (10.11; 10.12; 10.13; 10.21; 10.22; 10.23; 10.31; 10.32; 10.33), and wherein the control element (15) is capable of controlling each triplet of layers of electrochromic material independently. Interior equipment according to one of the preceding claims, in which the display module (1) has a thickness of less than 100 micrometers, for example between 40 and 60 micrometers. Interior equipment according to one of the preceding claims, in which the interior equipment (20) is a dashboard. Interior equipment according to one of claims 1 to 10, in which the interior equipment (20) is a door or a roof of a motor vehicle. Interior equipment according to one of claims 1 to 10, in which the interior equipment (20) is a motor vehicle seat. Interior equipment according to one of the preceding claims, wherein the display module (1) is comprised between a surface (22) of the interior equipment (20) and a cover element (21). Interior equipment according to one of the preceding claims, further comprising a transparent light module (100; 300; 400; 500) arranged opposite the first surface (13) of the display module (1) so as to illuminate said at least one layer of electrochromic material (10). Interior equipment according to claim 5 and claim 15, wherein 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. Interior equipment according to claim 15 or 16, wherein the transparent light module (100; 300; 400; 500) comprises:
at least one light guide (105; 305; 405.1; 405.2; 505.1; 505.2), each light guide comprising a transparent or semi-transparent flexible guide sheet (110; 310; 410.1; 410.2; 510.1; 510.2), the flexible guide sheet being capable of receiving light rays via 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 flexible guide sheet and at least one light injection element (120; 320.1; 320.2; 420.1; 420.2; 520.1; 520.2) capable of receiving light and distributing the light in the flexible guide sheet;
at least one light source (130; 330.1; 330.2; 430.1; 430.2; 530; 530.2) capable of injecting light into said at least one light injection element of each light guide. Interior equipment according to claim 17, wherein 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 opposite at least one layer of electrochromic material of the display module (1). Interior equipment according to claim 17 or 18, wherein the flexible guide sheet (110; 310; 410.1; 410.2; 510.1; 510.2) of each light guide (105; 305; 405.1; 405.2; 505.1; 505.2) has a thickness of between 10 micrometers and 1000 micrometers. Interior equipment according to one of claims 17 to 19, in which each light guide (105; 305; 405.1; 405.2; 505.1; 505.2) comprises a film made of polycarbonate, PC, polymethyl methacrylate, PMMA, thermoplastic polyurethane, TUP, or polyethylene terephthalate, PET. Interior equipment according to one of claims 17 to 20, 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 microstructures (113) etched by ultraviolet printing so as to return the light injected into the light guide according to a given pattern. Interior equipment according to claim 21, wherein, for each flexible guide sheet (110; 310; 410.1; 410.2; 510.1; 510.2), a surface density of microstructures (113) decreases with the distance from the injection edge of the guide sheet into which the light is injected. Motor vehicle comprising interior equipment according to one of the preceding claims.