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

Abstract

Disclosed is a display panel (20, 50) arranged inside a motor vehicle and comprising: a reflective support substrate (515), a first electrowetting layer (503) formed of cells that each contain a droplet of a liquid, the liquid droplet being coloured in a first colour selected from cyan, magenta and yellow; a second electrowetting layer (507) formed of cells that each contain a droplet of a liquid, the liquid droplet being coloured in a second colour selected from cyan, magenta and yellow; a third electrowetting layer (511) formed of cells that each contain a droplet of a liquid, the liquid droplet being coloured in a third colour selected from cyan, magenta and yellow, wherein the first (503), second (507) and third (511) electrowetting layers are superimposed on each other.

Description

A display panel arranged inside 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 arranged inside a motor vehicle. The invention also relates to a display system comprising this display panel and a method for displaying images on this 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 and interior design of their vehicles by altering the bodywork, grilles, lighting systems (front, rear, and side lights), and interior surfaces. 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 continuously improved to provide the best possible visibility for the driver, other drivers, 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] It is common today to use LCD screens 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.

[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 bottom or top of the microcapsule causes a color change on the surface of the coating.

[0007] Displaying images or animations on surfaces inside vehicles, such as dashboards or the backs of front seats, is now achieved using other technologies, for example, laser light sources. Such light sources are used to project animations onto dashboards. However, these technologies, in addition to being very energy-intensive, can also pose risks to the eyes of the driver or passengers.

[0008] Thus, all existing technologies have the drawback of being energy-intensive or posing risks to people inside the vehicle. In an era where we are seeking to reduce energy consumption, and in particular electricity consumption, there is therefore a need for a low-energy display device that can be installed inside the vehicle.

[0009] To address the aforementioned issues of energy consumption and interior vehicle layout, the applicant proposes a display panel using electrowetting technology.

[0010] According to a first aspect, the invention relates to a display panel arranged inside a motor vehicle, said display panel comprising: a reflective support substrate, 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 reflective support substrate, 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] This display panel has the advantage of being relatively flexible and, consequently, can be installed in various locations inside the vehicle. It also has the advantage of being energy-efficient and therefore relatively environmentally friendly. The display panel according to the first aspect of the invention can, for example, be mounted on the vehicle's dashboard or on the back of a front seat. The display panel according to the first aspect of the invention can be positioned on any surface inside the vehicle.

[0014] The superposition of layers of three colors – cyan, magenta and yellow – forms an image or colored surface that can take on a shade of color obtained by combining the three colors of the liquids.

[0015] The color combination is achieved by modifying the spread of the liquid within each layer. This is made possible by the electrode pairs positioned on either side of each layer. Applying an electrical voltage changes the electrostatic properties of the liquid and thus its ability to adhere to the cell surface. The liquid can then be placed in a dilated or contracted state depending on the voltage applied by the corresponding electrodes.

[0016] Other advantages of using electrowetting technology include: Low energy consumption, on the order of 6W / m² 2 Since the electrowetting layers do not emit light, the display panel does not produce light pollution; it can operate in very low temperatures, down to -40°C; and it operates on voltages between -16V and +16V. These voltage values ​​prevent electromagnetic compatibility issues with other vehicle equipment, particularly in the case of electric vehicles.

[0017] 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 reflective support substrate; the homogeneous luminous surface, arranged between the superposition of electrowetting layers and the reflective support substrate, acts as a backlighting layer 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 thanks to another light source;Each electrowetting layer is formed of cells, each cell comprising a liquid droplet, the dilated or contracted state of the liquid corresponding to a dilated or contracted state of each droplet; the superposition of three electrowetting cells containing droplets of three different colors forms a pixel, thus allowing the display of complex images; To be able to control each pixel independently, the first, second and third electrodes can be structured so as to apply a different electrical voltage to each electrowetting cell of each electrowetting layer; The display panel according to the first aspect of the invention is arranged on a dashboard on the passenger side; this arrangement of the display panel allows images or animations to be displayed clearly visible to the front passenger of the motor vehicle;These images may, for example, include information concerning external environmental conditions or the vehicle's operating status; The display panel may be arranged around the dashboard of the motor vehicle; this arrangement allows, for example, modification of the appearance of the front of the motor vehicle and in particular the parts around the steering wheel; these modifications allow, in particular, changing the color of the front of the vehicle, each color being, for example, associated with a vehicle operating mode or vehicle parameters; The display panel is arranged on the back of a front seat of the motor vehicle; this arrangement allows the display of images or animations visible to the rear passengers of the motor vehicle.

[0018] According to a second aspect, the invention relates to a display system for at least a first and a second image on a display panel arranged inside a motor vehicle according to one of the preceding claims, said system comprising: a display panel according to the first aspect of the invention, a power supply unit generating an electrical voltage, a first control device connected between the power supply unit and the first electrodes for controlling 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 for controlling 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 to control an expanded or contracted state of the liquid in the third electrowetting layer as a function of an electrical voltage level, and a control unit controlling the power supply unit and the first, second, and third control devices so as to display the first or second image.

[0019] Thanks to the control unit and the devices that manage the different layers, it is possible to control the expansion and contraction of the various liquid layers or droplets that form the pixels of the display panel. As a result, it is possible to modify the images and colors displayed by the panel inside the vehicle.

[0020] In addition to the features mentioned in the preceding paragraph, the display system according to one aspect of the invention may have one or more complementary features from the following, considered individually or according to all technically possible combinations: the display system includes means for activating the light device arranged near the transparent film according to an embodiment of the display panel according to the first aspect of the invention; alternatively, the display system may include means for activating the homogeneous light surface arranged above the substrate according to an embodiment of the display panel; 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 may include a light sensor arranged near the display panel; the activation means may then be triggered when the ambient light is less than a predetermined threshold value; the display device includes a user interface connected to the control unit to control, on a user command, the image to be displayed; the user interface thus allows control of the display panel to modify the image or the color displayed; the user interface includes an application installed on a user's mobile phone or on a dedicated remote control.

[0021] 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, in which an electrical voltage is applied to each electrowetting layer, this electrical voltage comprising 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.

[0022] The electrical voltage is applied by means of the first, second and third electrodes, controlled respectively by the first, second and third control device of the display device according to the second aspect of the invention.

[0023] If the electrowetting layers are formed by electrowetting cells, the step of applying an electrical voltage to each electrowetting layer includes applying an electrical voltage to each droplet in each electrowetting cell. In this case, the first and second levels of electrical voltage are associated with an expanded or contracted state of the droplets in each electrowetting cell.

[0024] In addition to the characteristics 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 applied voltage is zero when the vehicle is stationary and the applied voltage is positive when the vehicle is in operation; the method includes a step of activating a light device arranged in the vicinity of the display panel according to a first aspect of the invention, a first or second image being displayed at night by reflection of the light beam emitted by the light device, a first or second image being displayed during the day by reflection of ambient light on the display panel according to a first aspect of the invention;The method includes a step of receiving an instruction concerning the image to be displayed on the 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 to be automatically used according to the operating state of the vehicle. BRIEF DESCRIPTION OF THE FIGURES

[0025] Other advantages and features of the invention will become apparent from the following description, illustrated by the figures in which: Figure 1 represents an embodiment of a display panel arranged inside a motor vehicle according to one aspect of the invention; 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 schematically represents an embodiment of the layers of a display panel according to one aspect of the invention; Figure 5 schematically represents an embodiment of a display system according to the invention; and Figure 6 schematically represents an embodiment of a display method according to another aspect of the invention.

[0026] 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

[0027] 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.

[0028] Figure 1 illustrates a portion of a vehicle interior. In particular, it shows a dashboard 11, a steering wheel 12, and a portion of the windshield 13 defining the vehicle's interior. In the example shown in Figure 1, a display panel 20, according to a first aspect of the invention, is arranged at the front of the car's interior, and more specifically around the dashboard. The display panel 20 shown in Figure 1 can, for example, change color thanks to electrowetting layers, thus modifying the appearance of the vehicle's interior.

[0029] In another embodiment (not shown), the display panel 20 can be mounted on the passenger side of the dashboard. This allows images or animations to be displayed that are clearly visible to the front passenger without distracting the driver. The use of electrowetting layers reduces the display panel's energy consumption compared to existing technologies such as micro-LEDs or lasers.

[0030] According to another embodiment (not illustrated in the figure), the display panel 20 can be arranged on the back of a front seat of the motor vehicle. This arrangement allows images or animations to be displayed that are clearly visible to the rear passengers without distracting the driver.

[0031] More generally, the 20-inch display panel can be arranged on any surface inside the vehicle to display images, animations, or to change the appearance of the vehicle's interior.

[0032] 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 show useful information for the vehicle's driver or passengers. This information could, for example, concern the environmental conditions outside the vehicle.

[0033] Given its location, the display panel must be able to adapt to the conditions inside the vehicle, particularly changes in ambient light. It must also be relatively flexible to integrate seamlessly into the vehicle's interior, especially the dashboard. Furthermore, it must be energy-efficient, for example, to avoid using too much of the energy supplied by the vehicle's electric battery.

[0034] 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 cells are arranged against each other to form an electrowetting layer. Each cell, made of 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.

[0035] 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.

[0036] 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 side by side to form a flat surface, which is itself deposited on a reflective support substrate 33. This reflective support substrate 33, hereafter referred to as the reflective layer, can be a white material 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.

[0037] The droplets in each electrowetting layer can be tinted a predefined color to allow for a colorful 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.

[0038] 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.

[0039] 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.

[0040] 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 or a light source present inside the vehicle.

[0041] 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.

[0042] According to the example illustrated in Figure 1, the stack 50 further includes an electrically insulating layer 505, which separates 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 with 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.

[0043] 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.

[0044] The layer stack 50 further includes a third electrical insulating layer 513, a backlighting layer 514 and a reflective layer 515. In the case of a panel arranged inside the vehicle, the reflective layer is intended to be fixed to a surface inside the vehicle, for example by means of an adhesive layer.

[0045] The colors of the dielectric liquid droplets in the three electrowetting layers are chosen from cyan, magenta, and yellow. It is known that by appropriately combining one, two, or three of these colors through expansion or contraction, any shade of color can be obtained.

[0046] The superposition of three droplets, in the dilated or retracted state, from each of the first, second and third electrowetting layers forms a pixel of a first or second image.

[0047] 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.

[0048] The reflective layer 515 reflects light hitting the display panel, making it visible even in the presence of an external light source, such as daylight. Conversely, the backlighting layer provides a uniform illuminated surface to light up the stack of layers 50 that make up the display panel. This makes the display panel visible even without an external light source.

[0049] Alternatively, layer 501 could, for example, be a waveguide coupled to an LB light source. The light emitted by the LB source propagates within the waveguide or 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 inside the vehicle, even in the absence of daylight.

[0050] Laillustrates an embodiment of a display system 60 of at least a first and a second image on a display panel arranged between two luminous devices of a motor vehicle according to another aspect of the invention

[0051] As illustrated in Figure 1, the device 60 comprises a display panel 20 according to the first aspect of the invention and a first 61, a second 62, and a third 63 control device. Each control device is associated with an electrowetting layer included in the display panel. Each control device is connected between the electrowetting layer to which it is associated and a power supply unit 64 generating an electrical voltage.

[0052] This allows for controlling a dilated or contracted state for each droplet in 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.

[0053] If the electrowetting layers comprise several electrowetting cells, forming a plurality of pixels, the control devices 61, 62, and 63 are connected to the electrodes of each cell. Furthermore, the control devices are adapted to independently control each cell, and therefore each pixel.

[0054] Device 60 may further include a control unit to control the piloting devices so as to display the first or second image.

[0055] According to the embodiment illustrated in the figure, 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, by means of the user interface 66, modify the image displayed by the display panel 20. The user interface 66 can, for example, include an application installed on a mobile phone or on a dedicated remote control.

[0056] The display system 60 may also include means for activating the light source LB or the layer having a homogeneous luminous surface 514, particularly in the absence of an external light source to the display panel 20. These means may, for example, include a brightness sensor arranged near the display panel so as to measure the brightness locally in order to determine whether it is necessary to activate the light device LB or the homogeneous luminous surface 514.

[0057] 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.

[0058] 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.

[0059] Alternatively, the instruction can be part of a set of instructions saved in the control unit 65. These instructions can, for example, be used automatically depending on the operating state of the motor vehicle.

[0060] The process according to the third aspect of the invention may include a step 102 of applying an electrical voltage to each electrowetting layer by means of transparent electrodes placed on either side of each electrowetting layer.

[0061] Electrical voltage can be applied to each droplet if the layers are formed by electrowetting cells.

[0062] The applied electrical voltage has a first and a second level. These two voltage levels respectively ensure an expanded or contracted state for each droplet or liquid 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] The lighting device can, for example, be a transparent film with optical microstructures 501 or a backlighting layer 514.

[0067] 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 inside a motor vehicle, said display panel (20, 50) comprising: a reflective support substrate (515), 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 chosen from cyan, magenta and yellow, the first (503), second (507) and third (511) electrowetting layers being superimposed one on the other, above the reflective support substrate (515), 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 (502, 504), second (506, 508) or third electrodes (510, 512). Display panel (20, 50) according to claim 1, comprising 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 any one of the preceding claims comprising a homogeneous luminous surface (514) arranged above the reflective support substrate (515). Display panel according to any one of the preceding claims wherein each electrowetting layer is formed of cells, each cell comprising a droplet of liquid, the dilated or contracted state of the liquid corresponding to a dilated or contracted state of each droplet. Display panel according to one of the preceding claims, said display panel being arranged on a passenger-side dashboard. Display panel according to one of the preceding claims, said display panel being arranged around a dashboard. Display panel according to one of the preceding claims, said display panel being arranged on a rear face of a front seat of the motor vehicle. Display system (60) of at least a first and a second image on a display panel (20, 50) arranged inside a motor vehicle according to any one of the preceding claims, said system comprising: a display panel (20, 53) according to any one of claims 1 to 7, a power supply unit (64) generating an electrical voltage, a first control device (61) connected between the power supply unit (64) and the first electrodes for controlling 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 (62) connected between the power supply unit (64) and the second electrodes for controlling 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 (63) connected between the power supply unit (64) and the third electrodes to control an expanded or contracted state of the liquid in the third electrowetting layer as a function of an electrical voltage level, and a control unit controlling the power supply unit (64) and the first (61), second (62) and third (63) control devices so as to display the first or second image. Display system (60) according to claim 8 in which the control unit (65) includes means for activating the light device according to claim 2 or the light surface according to claim 3. Display system (60) according to the preceding claim wherein the means for activating the light device or the light surface include a light sensor arranged near the display panel (20, 50). Display system according to claim 8 or 9 comprising a user interface (66) connected to the control unit (65) to control, on command of a user, the image to be displayed. Display system according to any one of claims 8 to 11 in which the user interface (66) includes an application installed on a user's mobile phone or on a dedicated remote control. Method of displaying at least one 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. A method according to any one of claims 13 or 14, said method comprising a step of activating (103) a light device arranged in the vicinity of the display panel according to claim 2, a first or second image being displayed at night by reflection of the light beam emitted by the light device, a first or second image being displayed during the day by reflection of ambient light on the display panel according to claim 1.

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