Display panel arranged on a motor vehicle body, display system comprising such a panel and method of displaying on said panel

Abstract

Disclosed is a display panel (20, 50) arranged on a body of a motor vehicle in place of a radiator grill, comprising: - a first electrowetting layer (503) containing a liquid, the liquid being coloured in a first colour chosen from among cyan, magenta and yellow, - a second electrowetting layer (507) containing a liquid, the liquid being coloured in a second colour chosen from cyan, magenta and yellow, - a third electrowetting layer (511) containing a coloured liquid in a third colour chosen from cyan, magenta and yellow, the first (503), second (507) and third (511) electrowetting layers being superposed on one another, above the body (11) of the motor vehicle.

Description

A display panel mounted on the body of a motor vehicle, a display system comprising such a panel, and a method of displaying information on that panel. TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a display panel mounted on the body of a motor vehicle. The invention also relates to a display system comprising several display panels and a method for displaying images on a display panel.

[0002] The invention has applications in the field of land vehicles and in particular automobiles, to allow the display of information at a lower cost. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] It is well known that car manufacturers are constantly seeking to modify the exterior design of their vehicles by altering the bodywork, grilles, lighting systems (headlights, taillights, side lights), and so on. They also strive to make vehicles increasingly safer, both for passengers inside the vehicle and for those nearby. To this end, lighting and signaling systems are continually being improved to provide the best possible visibility for the driver, as well as for drivers of surrounding vehicles and pedestrians.

[0004] Various technologies are currently being implemented to meet these objectives of car manufacturers. For example, some display devices use the now common technology of light-emitting diodes (or LEDs). However, LED-based devices have the disadvantage of overheating and therefore requiring a cooling system, which makes them energy-intensive.

[0005] Today, LCD screens are commonly used for displaying information. However, the use of such screens is not only expensive and energy-intensive but also sensitive to environmental conditions such as temperature, humidity, and UV radiation. This makes the technology unsuitable for outdoor use, as the exterior equipment of a motor vehicle is subjected to varying environmental conditions, including inclement weather and exposure to mechanical shocks.

[0006] Another technology uses a coating based on electronic inks (or E-ink, in English terminology). This electrophoretic coating contains millions of microcapsules filled with a transparent fluid containing tiny particles of different colors and electrical charges. By applying a positive charge, the negative particles move to the top of the microcapsule and the positive particles move to the bottom, and vice versa. The movement of charges to the top or bottom of the microcapsule allows for a color change on the surface of the coating. This technology can, for example, be used on the body of a motor vehicle to modify its appearance.

[0007] However, this technology is not only a major energy consumer, but it is also only visible during the day, under the effect of ambient light.

[0008] Thus, all existing technologies have the drawback of being energy-intensive. In an era where we seek to reduce energy consumption, and in particular electricity consumption, there is therefore a need for a low-energy display device that can be mounted on the outside of the vehicle, for example on its bodywork.

[0009] To address the aforementioned issues of energy consumption and exterior vehicle layout, particularly in order to modify the appearance of the bodywork, the applicant proposes a display panel using electrowetting technology (or electrowetting in Anglo-Saxon terminology).

[0010] According to a first aspect, the invention relates to a display panel arranged on the body of a motor vehicle comprising: a first electrowetting layer, said first layer being positioned between a first electrode and a first reference electrode and containing a liquid, said liquid being colored in a first color chosen from cyan, magenta and yellow; a second electrowetting layer, said second layer being positioned between a second electrode and a second reference electrode and containing a liquid, said liquid being colored in a second color chosen from cyan, magenta and yellow; a third electrowetting layer, said third layer being positioned between a third electrode and a third reference electrode and containing a liquid, said liquid being colored in a third color chosen from cyan, magenta and yellow.

[0011] the first, second and third electrowetting layers being superimposed one on top of the other, above the body of the motor vehicle, the liquid in the first, second or third layer being in a dilated state or in a contracted state, said state being respectively determined by an electrical voltage of the first, second or third electrodes.

[0012] The electrical voltage of the first electrodes is defined as the difference in electrical voltage between the first electrode and the first reference electrode. The electrical voltage of the second electrodes is defined as the difference in electrical voltage between the second electrode and the second reference electrode. The electrical voltage of the third electrodes is defined as the difference in electrical voltage between the third electrode and the third reference electrode.

[0013] The dilated or contracted state refers to a dilated or contracted state of the liquid in the plane of the electrowetting layer in which the liquid is contained.

[0014] The three layers are superimposed and arranged above the vehicle's body, which then acts as a reflective layer. In other words, the display panel according to the first aspect of the invention functions as a reflective screen, with the images being visible through the reflection of external light such as daylight. Alternatively, a light source can be used to make the displayed images visible even in the absence of daylight.

[0015] The bodywork of the motor vehicle therefore replaces the reflective layer normally provided in billboards by electrowetting.

[0016] Since the display panel is intended to cover a portion of the bodywork, the image displayed can be a panel of uniform color.

[0017] This display panel has the advantage of being relatively flexible and, therefore, can be installed in various locations on the vehicle's body. It also has the advantage of being energy-efficient and thus relatively environmentally friendly.

[0018] The layering of three colors – cyan, magenta and yellow – forms a surface that can take on a shade of color obtained by combining the three colors of the liquids.

[0019] The color combination is achieved by modifying the spread of each liquid layer within the plane. This is made possible by the electrode pairs positioned on either side of each layer. Applying an electrical voltage to the liquid alters its electrostatic properties and thus its ability to adhere to the layer walls. The liquid can then be placed in a dilated or contracted state depending on the applied voltage.

[0020] In addition to the characteristics mentioned in the preceding paragraph, the display panel according to one aspect of the invention may have one or more complementary characteristics from among the following, considered individually or according to all technically possible combinations: the display panel according to the first aspect of the invention comprises a transparent film with optical microstructures, arranged above the superposition of the first, second and third electrowetting layers, the optical microstructures diffusing, in predetermined directions, a light beam emitted by a light device arranged in the vicinity of the display panel, said light beam propagating inside the transparent film; thanks to the transparent film with optical microstructures, it is possible to illuminate the display panel in the absence of an external light source such as sunlight;The display panel is therefore clearly visible even at night; the display panel has a homogeneous luminous surface, arranged above the vehicle body and below the superimposed electrowetting layers; the homogeneous luminous surface acts as a backlight for the display panel, making it visible even in the absence of an external light source; in other words, the transparent film with optical microstructures, just like the homogeneous light source, allows the images displayed on the display panel to be visible at night or in the absence of daylight. Thus, the displayed images are visible during the day, when ambient light is present, and at night with another light source; each electrowetting layer is formed by adjacent cells, each cell comprising a droplet of liquid;The superposition of three cells with droplets of different colors allows a pixel to be formed; the display panel then comprises a multiplicity of pixels allowing the display of complex images or animations.

[0021] According to a second aspect, the invention relates to a system for displaying at least a first and a second image on the body of a motor vehicle, said system comprising: a first and a second display panel according to the first aspect of the invention, a power supply unit generating an electrical voltage, a first control unit connected between the power supply unit and the electrodes of the first display panel, a second control unit connected between the power supply unit and the electrodes of the second display panel and a control unit controlling the power supply unit, the first and the second control unit, so as to display the first image on the first display panel and the second image on the second display panel.

[0022] Thanks to the control unit and the individual panel drives, it is possible to control the panels to display, for example, different images. As a result, it is possible to modify the images and colors displayed on the body of a motor vehicle.

[0023] In one embodiment, the display system can also include multiple display panels and multiple control units, each control unit being connected to the electrodes of a display panel. This allows, for example, covering a larger portion of the vehicle's bodywork or even the entire bodywork by using several display panels.

[0024] In addition to the characteristics mentioned in the preceding paragraph, the display system according to one aspect of the invention may have one or more complementary characteristics from the following, considered individually or in all technically possible combinations: each control unit comprises: a first control device connected between the power supply unit and the first electrodes of a display panel to control an expanded or contracted state of the liquid in the first electrowetting layer as a function of an electrical voltage level, a second control device connected between the power supply unit and the second electrodes of a display panel to control an expanded or contracted state of the liquid in the second electrowetting layer as a function of an electrical voltage level,a third control device connected between the power supply unit and the third electrodes of a display panel to control an expanded or contracted state of the liquid in the third electrowetting layer as a function of an electrical voltage level.

[0025] Thanks to the various control devices, it is possible to control each electrowetting layer of each display panel and thus display a wide variety of shades of colors and images; the control unit includes means for activating a luminous device of a display panel according to the first aspect of the invention; alternatively, the display system may include means for activating the homogeneous luminous surface above the body and below the electrowetting layers of the display panel according to a first aspect of the invention; this makes it possible to make the display panel visible even at night or generally in the absence of an external light source.The means for activating the light device or the homogeneous light surface can be connected to a light sensor and trigger when the ambient light is less than a predetermined threshold value; the display device includes a user interface connected to the control unit to command, on a user's command, an image to be displayed; the user interface thus allows control of the display panels to change the images displayed, for example by displaying a different image on each display panel included in the display system; the user interface includes an application installed on a user's mobile phone or on a dedicated remote control.

[0026] A third aspect of the invention relates to a method of displaying at least a first and a second image on a display panel according to the first aspect of the invention comprising a step of applying an electrical voltage to the liquid of each electrowetting layer, this electrical voltage having a first level and a second level, each of these first and second levels ensuring a dilated or a contracted state of the liquid, the superposition of liquids, in the dilated or contracted state, of each of the first, second and third electrowetting layers forming the image.

[0027] The electrical voltage is applied by means of the first, second and third electrodes, controlled by a control unit of the display device according to the second aspect of the invention.

[0028] In addition to the characteristics just mentioned in the preceding paragraph, the display method according to one aspect of the invention may have one or more complementary characteristics from among the following, considered individually or according to all technically possible combinations: the first level of the electrical voltage is a predefined positive voltage and the second level of the electrical voltage is a zero voltage so that a first image is displayed on the display panel when the applied voltage is positive and a second image is displayed on said display panel when the applied voltage is zero; the applied voltage is zero when the vehicle is stationary and the applied voltage is positive when the vehicle is in operation;The method comprises a step of activating a lighting device on a display panel according to a first aspect of the invention, the image being displayed by reflection of a light beam emitted by the lighting device; the method comprises a step of activating a homogeneous luminous surface on a display panel according to a first aspect of the invention, the image being displayed by reflection of a light beam emitted by the lighting device; the method comprises a step of receiving an instruction concerning the image to be displayed on a display panel, the voltage applied to the electrowetting layers being determined on the basis of said image to be displayed; the instruction can, for example, be sent by a user from a user interface; alternatively, a set of instructions can be saved in the control unit for automatic use depending on the operating state of the vehicle. BRIEF DESCRIPTION OF THE FIGURES

[0029] Other advantages and features of the invention will become apparent from the following description, illustrated by the figures in which: Figure 1 represents an example of a vehicle equipped with a display panel fitted to its bodywork according to the prior art; Figure 2 represents, from several views, examples of droplets of a liquid used in an electrowetting layer; Figure 3 represents examples of superimposed electrowetting layers; Figure 4 represents schematically an example of the structure of a display panel according to the invention; Figure 5 represents schematically the display system according to the invention; and Figure 6 represents schematically an embodiment of a display method according to another aspect of the invention.

[0030] In the figures, identical elements are identified by identical references. For the sake of readability, the size scales between represented elements are not respected. DETAILED DESCRIPTION

[0031] An example of an embodiment of a display panel using electrowetting technology and of a system comprising this display panel are described in detail below, with reference to the accompanying drawings. These examples illustrate the features and advantages of the invention. It should be noted, however, that the invention is not limited to these examples.

[0032] An example of a state-of-the-art vehicle 10 is shown in Figure 1. Like the vast majority of current vehicles, this vehicle 10 has a body 11 and lighting devices 12. The body 11 is covered by several display panels 13 using electronic inks. These display panels 13, arranged on the vehicle's body 11, allow its exterior appearance to be changed, adapting it, for example, to visibility conditions.

[0033] The electronic inks used today are still an energy-intensive technology. Furthermore, these electronic inks require external light to be visible.

[0034] For these reasons, the display panel according to a first aspect of the invention is arranged on a vehicle body and uses electrowetting technology.

[0035] Such a display panel can offer a design area, for example by displaying the car manufacturer's logo or any predefined image. This display panel can also provide safety information, visible to pedestrians, such as the distance between the pedestrian and the vehicle. In the specific case of drivers and taxis, the display panel can indicate whether the vehicle is available or occupied.

[0036] Given its location, the display panel must be able to withstand outdoor conditions, such as rain, cold, and sun. It must also be relatively flexible to integrate seamlessly into the vehicle's bodywork. Furthermore, it must be energy-efficient to avoid using too much of the vehicle's battery power.

[0037] To achieve this, the display panel according to the invention uses electrowetting technology. This electrowetting technology, already known for its applications in lenses, is based on modifying the wetting properties of a generally hydrophobic surface by applying an electrical voltage between a solid and a conductive liquid. For this purpose, electrowetting layers formed by one or more electrowetting cells are used. Each cell, formed from a transparent hydrophobic material, contains within it a droplet of a conductive fluid, such as an electrically conductive oil, hereinafter referred to as a droplet.

[0038] When an electrical voltage is applied to an electrowetting cell via a pair of electrodes, the droplet either expands or contracts. Depending on the fluid used, two configurations can occur: either the electrowetting droplet is expanded in its natural state and contracts when subjected to an electrical voltage, or the electrowetting droplet is contracted in its natural state and expands when subjected to an electrical voltage.

[0039] Regardless of the configuration, examples of contracted and dilated droplets are shown on the diagram. Drawings A1, B1 and C2 show a contracted droplet, while drawings A2, B2 and C1 show a dilated droplet. In particular, drawings A1 and A2 show a single droplet, respectively, contracted 31 and dilated 32. Drawings B1 and B2 show several electrowetting cells 35 when the droplet is, respectively, contracted 31 and dilated 32. Drawings C1 and C2 show a portion of an electrowetting layer 30 containing an electrowetting cell 35 when the droplet of the cell is, respectively, dilated 32 and contracted 31. Drawings C1 and C2 show in particular that an electrowetting cell 35 is formed between two horizontal walls 34.1, 34.2 and two vertical walls 34.3 each formed in a transparent film or a glass plate.Several cells 35 are positioned next to each other so as to form a flat surface, itself deposited on a reflective support substrate 33. Alternatively, each electrowetting layer may comprise a single cell.

[0040] This reflective support substrate 33, hereinafter referred to as the reflective layer, can be a white substrate or a mirror. Whether white or mirrored, the reflective layer 33 is designed to reflect light rays through the electrowetting layer. Thus, when the droplets are contracted, the human eye will see a luminous panel of the same color as the reflective layer 33, and when the droplets are expanded, the human eye will see a luminous panel of the same color as the droplets. In one embodiment of the display panel according to the first aspect of the invention, the reflective layer is a portion of the vehicle's body. When the droplets are contracted, the color of the bodywork then becomes visible from the outside.

[0041] The droplets in each electrowetting layer can be tinted a predefined color to allow for a colored display on the display panel. To create a multicolor display panel, several electrowetting layers are superimposed. Lamontre shows four possible states of a multicolor display panel comprising three layers: 30.1, 30.2, and 30.3. The droplets within each layer are colored a distinct color. For example, an electrowetting layer 30.1 might contain cyan droplets, another electrowetting layer 30.2 might contain magenta droplets, and another electrowetting layer 30.3 might contain yellow droplets. The layering of cyan, magenta, and yellow is well-established and allows for obtaining any desired color depending on their positioning.

[0042] For example, in state 4.1, the three droplets are expanded. The light arriving at the display panel is then completely absorbed, and the panel appears black or dark. In state 4.2, the three droplets are contracted; the light arriving at the display panel is then completely reflected by a reflective surface, and the panel appears the same color as the ambient light.

[0043] State 4.3 illustrates a way to obtain the color green by expanding only the yellow droplet 30.3 and the cyan droplet 30.1. State 4.4 illustrates a way to obtain the color red by expanding only the yellow droplet 30.3 and the magenta droplet 30.2.

[0044] Lamontre shows an example of a stack of 50 layers to form a multicoloured display panel according to one aspect of the invention. The arrow L indicates the external light illuminating the device 50, for example daylight.

[0045] In the example illustrated in Figure 1, the stack of layers 50 comprises a layer 501 consisting of a transparent film, a first transparent electrode 502, and a first electrowetting layer 503 comprising at least one cell. Each cell in the first electrowetting layer contains a droplet of colored liquid. Layer 504 is a first transparent reference electrode which, in conjunction with the first transparent electrode 502, allows an electrical voltage to be applied to the droplets of colored liquid in the electrowetting layer.

[0046] According to the example illustrated in Figure 1, the stack 50 further includes an electrically insulating layer 505, allowing the separation of the first electrowetting layer 503 and its first electrodes 502, 504 from a second part of the device comprising a second transparent electrode 506, a second electrowetting layer 507, and a second transparent reference electrode 508. As in the case of the first electrowetting layer 503, the second electrowetting layer includes at least one electrowetting cell with a colored liquid droplet. The second transparent electrodes 506 and 508 allow an electrical voltage to be applied to the droplets of the second wetting layer 507.

[0047] A second electrically insulating layer 509 separates the second part of the device from a third part of the device comprising a third transparent electrode 510, a third electrowetting layer 511 and a third reference electrode 512. The third electrowetting layer 511 comprises at least one electrowetting cell containing a colored liquid droplet.

[0048] The layer stack 50 further includes a third electrical insulating layer 513 and a backlighting layer 514. The stack 50 is arranged on the body 11 of the motor vehicle, the body 11 acting as a reflective layer for the light passing through the layer stack 50.

[0049] The colors of the liquid in the three electrowetting layers are chosen from cyan, magenta, and yellow. It is known that by appropriately combining two or three of these colors, through the expansion or contraction of the liquid in the different layers, any shade of color can be obtained.

[0050] The superposition of three layers of liquid, in the dilated or contracted state, of each of the first, second and third electrowetting layers forms a pixel of a first or second image.

[0051] In the presence of multiple electrowetting cells, and therefore multiple pixels, the first, second, and third electrodes can be structured to address each electrowetting cell separately. This allows each pixel of the display panel to be controlled independently.

[0052] The vehicle's bodywork 11 reflects the light arriving on the display panel, making it visible even in the presence of an external light source, such as daylight. Conversely, the backlighting layer provides a homogeneous illuminated surface to light the stack of 50 layers that form the display panel. This makes the display panel visible even in the absence of an external light source.

[0053] Alternatively, layer 501 could, for example, be a waveguide coupled to an LB light source. The light emitted by the LB source propagates through the transparent film 501 by total internal reflection. The lower surface 501b of film 501 could include microstructures adapted to diffuse the light propagating within film 501. The light extracted by the optical microstructures of face 501b could then illuminate the electrowetting layers, making the display panel visible from the outside even in the absence of daylight.

[0054] Laillustre an embodiment of a display system 60 of at least a first and a second image on a body of a motor vehicle according to another aspect of the invention.

[0055] As illustrated in Figure 1, the device 60 comprises a first display panel 20 according to the first aspect of the invention and a second display panel 21 according to the first aspect of the invention. The device 60, as illustrated in Figure 1, further comprises a power supply unit 64, a first control unit 61, and a second control unit 62. The first control unit 61 is connected between the power supply unit 64 and the electrodes of the first display panel 20. The second control unit 62 is connected between the power supply unit 64 and the electrodes of the second display panel 21.

[0056] According to the example in Figure 1, the first control unit 61 comprises a first control device 61.1, a second control device 62.1, and a third control device 61.3. Each control device is associated with an electrowetting layer included in the first display panel 20. Each control device is connected between the electrowetting layer to which it is associated and the power supply unit 64 that generates an electrical voltage. The second control unit 62 comprises a first control device 62.1, a second control device 62.2, and a third control device 62.3. Each control device is associated with an electrowetting layer included in the second display panel 20. Each control device is connected between the electrowetting layer to which it is associated and the power supply unit 64 that generates an electrical voltage.

[0057] This allows for the control of an expanded or contracted state for each droplet or liquid layer within the electrowetting layers by varying the electrical voltage applied to each layer. Specifically, each control device is electrically connected to transparent electrodes positioned on either side of the electrowetting layer to which it is attached.

[0058] If the electrowetting layers comprise several electrowetting cells, forming a plurality of pixels, the driver devices 61.1, 61.2, 61.3, 62.1, 62.2, 62.3 are connected to the electrodes of each cell. Furthermore, the driver devices are adapted to independently drive each cell, and therefore each pixel.

[0059] The device 60 may further include a control unit 65 connected to the power supply unit 64 to control the driving units 61 and 62 so as to display the first image on the first display panel 20 and / or the second image on the second display panel 21. The control unit may, for example, include data processing and storage means such as a microprocessor and memory.

[0060] According to the embodiment illustrated in Figure 1, the device 60 further includes a user interface 66 connected to a control unit 65. The control unit 65 is then connected to the power supply unit 64. A user can therefore, through the user interface 66, modify the images displayed by the display panels 20 and 21. The user interface 66 may, for example, include an application installed on a mobile phone or on a dedicated remote control.

[0061] The diagram schematically illustrates the steps of an embodiment of the method of displaying at least a first and a second image on a display panel according to the first aspect of the invention.

[0062] According to the example illustrated in Figure 1, the method 100 includes a step 101 of receiving an instruction concerning the image to be displayed on the display panel. In one embodiment, the instruction can be given by a user via a user interface of the display system 60 according to one aspect of the invention.

[0063] Alternatively, the instruction can be part of a set of instructions stored in the control unit 65. These instructions can, for example, be executed by the microprocessor of the control unit depending on the operating state of the motor vehicle. For example, this could be a sequence of images or color shades to be displayed on the display panels mounted on the vehicle's body.

[0064] The method according to the third aspect of the invention may include a step 102 of applying an electrical voltage to the liquid or to each droplet of each electrowetting layer. The electrical voltage is applied to each liquid or each droplet by means of transparent electrodes placed on either side of each electrowetting layer.

[0065] The applied electrical voltage has a first and a second level. These two voltage levels respectively ensure an expanded or contracted state for each liquid or droplet in the three electrowetting layers. The superposition of three droplets from each of the first, second, and third electrowetting layers forms a pixel of a first or second image.

[0066] In one embodiment, the first level of the applied electrical voltage is a predefined positive voltage, and the second level is zero. The first voltage level corresponds to the display of a first image on the display panel. The second voltage level corresponds to the display of a second image on the display panel.

[0067] In an embodiment of the process according to the third aspect of the invention, when the motor vehicle is at rest the applied voltage is zero.

[0068] According to the embodiment illustrated in Figure 1, the method according to the third aspect of the invention further comprises a step 103 of activating a lighting device arranged in the vicinity of the display panel according to the first aspect of the invention. The lighting device illuminates the display panel in the absence of an external light source such as daylight.

[0069] The lighting device can, for example, be a transparent film with optical microstructures 501 or a backlighting layer 514.

[0070] Although described through a number of examples, variants and embodiments, the display panel, the display system and the display method according to the various aspects of the invention include various variants, modifications and improvements which will be obvious to a person skilled in the art, it being understood that these variants, modifications and improvements form part of the scope of the invention.

Claims

Display panel (20, 50) arranged on a body (11) of a motor vehicle comprising: a first electrowetting layer (503), said first layer (503) being positioned between a first electrode (502) and a first reference electrode (504) and containing a liquid, said liquid being colored in a first color selected from cyan, magenta and yellow; a second electrowetting layer (507), said second layer (507) being positioned between a second electrode (506) and a second reference electrode (508) and containing a liquid, said liquid being colored in a second color selected from cyan, magenta and yellow; a third electrowetting layer (511), said third layer being positioned between a third electrode (510) and a third reference electrode (512) and containing a liquid, said liquid being colored in a third color selected from cyan, magenta and yellow,the first (503), second (507) and third (511) electrowetting layers being superimposed one on top of the body (11) of the motor vehicle, the liquid in the first, second or third layer being in an expanded or contracted state, said state being respectively determined by an electrical voltage of the first (502, 504), second (506, 508) or third electrodes (510, 512). Display panel (20, 50) according to claim 1, characterized in that it comprises a transparent film (501) with optical microstructures, arranged above the superposition of the first, second and third electrowetting layers, the optical microstructures diffusing, in predetermined directions, a light beam emitted by a light device (LB) arranged in the vicinity of the display panel (20, 50), said light beam propagating inside the transparent film (501). Display panel according to claim 1, characterized in that it comprises a homogeneous luminous surface (514) arranged above the car body and below the superimposed electrowetting layers. Display system (60) of at least a first and a second image on a body (12) of a motor vehicle, said system comprising: a first and a second display panel (20, 21) according to any one of claims 1 to 3, a power supply unit (64) generating an electrical voltage, a first control unit (61) connected between the power supply unit (64) and the electrodes of the first display panel (20), a second control unit (62) connected between the power supply unit (64) and the electrodes of the second display panel (21) and a control unit (65) controlling the power supply unit (64), the first (61) and the second (62) control unit, so as to display the first image on the first display panel (20) and the second image on the second display panel (21). Display system according to the preceding claim characterized in that each control unit (61,62) comprises: a first control device (61.1, 62.1) connected between the power supply unit (64) and the first electrodes of a display panel (20,21) to control an expanded or contracted state of the liquid of the first electrowetting layer as a function of an electrical voltage level, a second control device (61.2, 62.2) connected between the power supply unit (64) and the second electrodes of a display panel (20,21) to control an expanded or contracted state of the liquid of the second electrowetting layer as a function of an electrical voltage level, a third control device (61.3, 62.3) connected between the power supply unit (64) and the third electrodes of a display panel (20, 21) to drive an expanded or contracted state of the liquid in the third electrowetting layer as a function of an electrical voltage level. Display system (60) according to claim 4, characterized in that the control unit (65) includes means for activating a light device according to claim 2 or a light surface according to claim 3. Display system according to claim 4 or 5, characterized in that it comprises a user interface (66) connected to the control unit (65) to command, on the order of a user, an image to be displayed. Display system according to the preceding claim, characterized in that the user interface (66) comprises an application installed on a user's mobile phone or on a dedicated remote control. Method of displaying at least a first and a second image on a display panel according to any one of claims 1 to 3, comprising a step of applying an electrical voltage (102) to each electrowetting layer, this electrical voltage having a first level and a second level, each of these first and second levels ensuring a dilated or a contracted state of the liquid of each electrowetting layer, the superposition of the liquids, in the dilated or contracted state, of each of the first, second and third electrowetting layers forming a first or a second image. Display method according to the preceding claim, wherein the applied voltage is zero when the vehicle is stationary and the applied voltage is non-zero when the vehicle is in operation. Method according to any one of claims 9 or 10, said method comprising a step of switching on (103) a lighting device of a display panel according to claim 2, the image being displayed by reflection of a light beam emitted by the lighting device.

Images