Lighting and signalling device for a motor vehicle

Abstract

The present invention relates mainly to a lighting and signalling device (1) comprising at least one luminous module (4) capable of generating a lighting beam (A) along a longitudinal optical axis and an optical element (2) through which the lighting beam (A) is projected, characterised in that the lighting and signalling device (1) comprises a controllable liquid-crystal screen (18) pressed against the optical element (2), the controllable liquid-crystal screen (18) being capable of adopting different diffusion states, including at least one state of projection of the lighting beam (A) in which the controllable liquid-crystal screen (18) is transparent and a state of emission of a signalling beam in which the controllable liquid-crystal screen (18) is at least partially diffusing.

Description

[0001] DESCRIPTION

[0002] Title ■ Lighting and signaling device for a motor vehicle.

[0003] The invention relates to the field of lighting and / or light signaling in the automotive field.

[0004] The field of lighting and / or light signaling of motor vehicles is subject to regulations which require that each motor vehicle be equipped with lights, fulfilling specific safety functions, and in particular signal lights, dipped beam headlights and main beam headlights. Signal lights are generally used to communicate information to other road users, without there being any other function of lighting the road scene useful to the driver of the vehicle, such as for example direction indicator lights or daytime running lights (also called "DRL", for the English term "Daytime Running Lamp"). Dipped beam headlights allow the driver of a motor vehicle to be seen by other users and the driver to see the road properly up to 30 meters, without dazzling users present on the road scene.The main beam headlights allow the driver to see the road properly up to 100 meters, but can dazzle other road users, and should only be used outside built-up areas and when there are no other users in front of the motor vehicle.

[0005] In the interests of compactness of the lighting means of a motor vehicle, it is sought to group together within a single headlight the different means allowing the implementation of these signaling functions and these lighting functions, and it may in particular be aimed at by automobile manufacturers or by equipment manufacturers to have a common optical element for each of these functions, for example in the form of a transparent or translucent screen closing the housing of the headlight and from which emerge the light rays forming one or other of the lighting or signaling beams.

[0006] In this context of a common optical element, it is also sought to have an extent of the lighting surface equal from one function to another, in particular for questions of aesthetics and visual identity of the lighting means. But this research is made complicated by the different characteristics of the lighting and / or signaling functions, with on the one hand the directive character that a lighting beam must respect and the diffuse character that a signaling beam presents. The presence of diffusing means to generate this signaling beam can hinder the propagation of the rays intended for the formation of a regulatory lighting beam.

[0007] The present invention falls within this context by proposing a lighting and signaling device comprising at least one light module capable of generating a lighting beam along a longitudinal optical axis and an optical element through which the lighting beam is projected, remarkable in that the lighting and signaling device comprises a controllable liquid crystal screen pressed against the optical element, the controllable liquid crystal screen being capable of taking different diffusion states among which at least one state of projection of the lighting beam in which the controllable liquid crystal screen is transparent and a state of emission of a signaling beam in which the controllable liquid crystal screen is at least partially diffusing.

[0008] Such a lighting and signaling device may be installed on a vehicle to be used as signaling lights, dipped beams and / or main beams for example and thus enable the generation of lighting or signaling beams on the same display surface, without the presence of the signaling lights disrupting the regulatory operation of the main beams or dipped beams capable of illuminating the road of the vehicle equipped with this lighting and signaling device.

[0009] In the lighting and signaling device according to the invention, the light module is configured to generate a lighting beam projected towards the optical element. It is understood that, when the lighting and signaling device is installed on a motor vehicle, it is the lighting beam which is used to produce the dipped beam headlights and / or the main beam headlights. In addition, the lighting and signaling device comprises a housing in which the light module is installed, the optical element being able for example to form a closing element of said housing. In other words, the optical element participates in forming one of the walls of the housing in which the light module is housed, the latter projecting the lighting beam onto the road scene through the optical element.

[0010] The controllable liquid crystal display is affixed to this optical element to form an optical block which can strongly diffuse the passage of the lighting beam or which can, on the contrary, weakly diffuse the passage of the lighting beam through the optical element.

[0011] Furthermore, "transparent" means that the controllable liquid crystal screen is capable of allowing light beams to pass through itself without generating any significant disturbance to said light beams, for example other than Fresnel reflections when passing through the controllable liquid crystal screen.

[0012] Furthermore, the states of the controllable liquid crystal display can be defined according to the haze, or Haze index, presented by said controllable liquid crystal display. For example, in the projection state, the controllable liquid crystal display has a haze, or Haze index, of low value, for example less than 6%.

[0013] Advantageously, the diffusion veil of the controllable liquid crystal screen is approximately 3% when said screen is in the projection state.

[0014] Conversely, in the emission state of a signaling beam, the controllable liquid crystal screen has a high value of diffusion haze, for example more than 90%. Advantageously, the diffusion haze of the controllable liquid crystal screen is approximately 98% when said screen is in the emission state.

[0015] According to an optional feature of the invention, the controllable liquid crystal screen is arranged between the optical element and the light module. The controllable liquid crystal screen is advantageously arranged between the light module and the optical element so that, when the optical unit is transparent as a whole, the lighting beam generated by the light module is caused to pass successively through the controllable liquid crystal screen and through the optical element.

[0016] The invention may include one or more features that are described below, which features may be taken alone or in combination with other features.

[0017] According to an optional feature of the invention, the controllable liquid crystal screen is fixed to the optical element by gluing.

[0018] According to an optional feature of the invention, the controllable liquid crystal screen is fixed to the optical element by means of an optical adhesive. The term "optical adhesive" means a transparent adhesive having an optical index close to at least one of the bonded elements, i.e. here the controllable liquid crystal screen and / or the optical element.

[0019] According to an optional feature of the invention, the controllable liquid crystal screen is fixed to the optical element by overmolding.

[0020] According to an optional characteristic of the invention, the controllable liquid crystal screen comprises two transparent walls, a polymer matrix extending between the two transparent walls and in which liquid crystals are dispersed and two electrodes associated respectively with one of the transparent walls so as to pass an electric current through the polymer matrix and its liquid crystals.

[0021] According to an optional feature of the invention, at least one wall comprises a current-conducting layer directly in contact with the polymer matrix and an electrically insulating layer arranged to cover the conductive layer opposite the polymer matrix. The conductive layer may be formed from indium tin oxide (ITO) and the insulating layer may be formed from polycarbonate (PC) or polyethylene terephthalate (PET).

[0022] According to an optional characteristic of the invention, the controllable liquid crystal screen comprises an internal transparent wall facing the light module and an external transparent wall facing the external medium of the lighting and signaling device, the optical element being constitutive of the external transparent wall. According to an optional characteristic of the invention, the lighting and signaling device comprises a control member of the controllable liquid crystal screen configured to electrically power the controllable liquid crystal screen so that the controllable liquid crystal screen changes from a projection state to a state of emission of a signaling beam and vice versa depending on a modification of the electrical power supply.Under the effect of an electrical supply to the controllable liquid crystal screen, and more particularly an electrical supply to the polymer matrix via the electrodes, the liquid crystals embedded in the polymer matrix are all oriented parallel to the direction of the electric current passing through the polymer matrix, that is to say perpendicular to the transparent walls of the screen. In such a configuration, the light beam is able to pass through the controllable liquid crystal screen without being deflected by the liquid crystals which are arranged in the main direction of propagation of the light beam, so as to form a regulatory lighting beam.

[0023] According to another example of the invention, the liquid crystals are naturally oriented so as to allow the light beam to pass through the controllable liquid crystal screen without electrical power supply. In this example of the invention, under the effect of an electrical power supply to the controllable liquid crystal screen, and more particularly an electrical power supply to the polymer matrix via the electrodes, the liquid crystals embedded in the polymer matrix are all oriented randomly, so as to make the light beam diffuse when it passes through the controllable liquid crystal screen.

[0024] According to an optional characteristic of the invention, the control member is electrically connected to each of the electrodes of the controllable liquid crystal screen.

[0025] According to an optional characteristic of the invention, the lighting and signaling device comprises a main light source constituting the light module and an additional light source installed opposite the optical element.

[0026] According to an optional characteristic of the invention, the main light source is configured to participate in generating a light beam intended to pass through an optical block formed by the controllable liquid crystal screen and the optical element, this light beam being capable of forming a lighting beam or a signaling beam depending on the diffusion state of the controllable liquid crystal screen.

[0027] According to an optional feature of the invention, the additional light source is configured to participate in generating a signaling beam.

[0028] According to an optional characteristic of the invention, the main light source and the additional light source are powered simultaneously or separately.

[0029] According to an optional characteristic of the invention, the optical element has an internal face in contact with the controllable liquid crystal screen, an opposite external face and a peripheral edge connecting the internal face to the external face, the additional light source being installed opposite the peripheral edge of the optical element.

[0030] According to an optional characteristic of the invention, the controllable liquid crystal screen comprises a first portion and a second portion extending at the periphery of the first portion, the diffusion state of one of the portions of the controllable liquid crystal screen being independent of the diffusion state of the other of said portions.

[0031] According to an optional characteristic of the invention, the first portion is electrically powered by the control member independently of the second portion.

[0032] According to an optional characteristic of the invention, the lighting and signaling device comprises an element for diffusing light rays arranged opposite the second portion of the controllable liquid crystal screen.

[0033] According to an optional feature of the invention, the diffusion element comprises a film installed between the controllable liquid crystal screen and the optical element.

[0034] According to an optional characteristic of the invention, the optical element comprises a main zone facing the first portion of the controllable liquid crystal screen and a zone peripheral to the main zone facing the second portion of the controllable liquid crystal screen, the diffusion element constituting the peripheral zone of the optical element.

[0035] According to an optional characteristic of the invention, the lighting and signaling device comprises a masking member arranged to cover the periphery of the external face of the optical element.

[0036] The invention also relates to a motor vehicle equipped with at least one lighting and signaling device in accordance with what has been previously described.

[0037] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and several examples of embodiment given for informational and non-limiting purposes with reference to the appended schematic drawings on the other hand, in which:

[0038] [Fig. i] is a schematic representation of a first embodiment of a lighting and signaling device according to the invention, with an optical unit formed from an optical element and a controllable liquid crystal screen, in a first configuration in which at least a portion of the controllable liquid crystal screen is in a projection state, that is to say a so-called transparent state;

[0039] [Fig. 2] is a schematic representation of the first embodiment of the lighting and signaling device shown in figure i, in a second configuration in which the controllable liquid crystal screen is in a signaling beam emission state, i.e. a so-called diffusing state;

[0040] [Fig. 3] is a schematic representation of the first embodiment of the lighting and signaling device shown in Figure 1, in a third configuration in which the controllable liquid crystal screen is in a signaling beam emission state, i.e. a so-called diffusing state;

[0041] [Fig. 4] is a schematic representation of a second embodiment of a lighting and signaling device according to the invention; [Fig. 5] is a schematic representation of a third embodiment of a lighting and signaling device according to the invention.

[0042] The features, variants and different embodiments of the invention may be combined with each other in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0043] In the figures, elements common to several figures retain the same reference.

[0044] In Figure 1 is illustrated a lighting and signaling device 1 according to the invention equipping a motor vehicle and in particular configured to generate a lighting beam or a signaling beam A mainly along a longitudinal optical axis L.

[0045] The lighting and signaling device 1 comprises an optical element 2 through which a light beam A is projected to form the lighting beam capable of illuminating the road scene. The optical element 2 thus forms a luminous surface of the lighting and signaling device, the shape and dimensions of which impact the visual identity of the function

[0046] The lighting and signaling device 1 comprises a light module 4 which is configured to generate the light beam A and direct it towards the optical element 2 and it is understood that this light module 4 can project a light beam capable of forming a dipped beam type lighting function and / or a main beam type lighting function.

[0047] According to the invention, and as visible in Figures 1 to 5, the lighting and signaling device 1 comprises a controllable liquid crystal screen 18 pressed against the optical element 2 to form an optical block arranged in the direction of which the light beam A is directed when the light module 2 is active. The controllable liquid crystal screen 18 is arranged between the optical element 2 and the light module 4, so that it is the optical element which is turned towards the outside of the lighting and signaling device and forms the luminous surface of this device.

[0048] As will be described in more detail below, controlling the controllable liquid crystal screen 18 makes it possible to modify its diffusion state and the general diffusion state of the optical unit and therefore to modify the impact that the optical unit can have on the projection of the light beam towards the road scene. In other words, the light module is intended to project a light beam which passes through the optical unit while being little or not deflected by this optical unit if the controllable liquid crystal screen 18 is transparent, or else by being deflected and therefore made diffuse if the controllable liquid crystal screen 18 is diffusing.

[0049] As illustrated in Figure i, the lighting and signaling device i comprises a housing 6 on which the optical element 2 is fixed, and more particularly the optical block formed of the optical element and the controllable liquid crystal screen 18, and in which the light module 4 is housed. The optical element 2 forms at least part of one of the walls of the housing 6, having an external face 8 oriented towards the outside of the lighting and signaling device 1, and an internal face 10 which participates in delimiting at least in part a housing of the light module 4. The optical element 2 is, for example, a transparent screen through which the light beam A is able to be projected. The optical element 2 is optically neutral, that is to say that it does not deflect the light rays, without this being limiting for the invention.

[0050] As visible in Figures 1 to 5, the lighting and signaling device 1 comprises a main light source constituting the light module 4 and an additional light source 12 installed opposite the optical element 2. The main light source is here configured to participate in the formation of the light beam A while the additional light source 12 is configured to participate in the formation of a signaling beam.

[0051] The main light source, not visible in the figures because it is housed in a casing of the light module, is for example formed by one or more light-emitting diodes, commonly called LEDs, and configured to generate light rays. The light module 4 may comprise, in addition to the main light source, an optical member, the main light source being configured to emit light rays towards the optical member.

[0052] The optical member is configured to group the light rays emitted by the main light source into a light beam A in the direction at least of the optical element 2.

[0053] The optical organ may consist of a projection lens.

[0054] The optical member may further comprise a reflector, or reflective element, arranged opposite the main light source, the reflector having the function of directing the light rays emitted by the main light source towards the projection lens.

[0055] The optical member may, alternatively, comprise a reflector having the function of directing the light rays emitted by the main light source towards the optical element 2.

[0056] Generally, the optical member may comprise one or more reflectors, one or more lenses, as well as any combination of one or more reflectors and one or more lenses.

[0057] The additional light source 12 is arranged opposite a transverse edge 16 of the optical element 2. The transverse edge 16 of the optical element 2 is a face of the optical element 2 connecting at the periphery the internal face 10 and the external face 8 of the optical element 2. In other words, the additional light source 12 projects light rays within the optical element 2 from a slice of the latter, the light rays propagating by successive total reflections within the optical element 2, in a direction originally substantially perpendicular to the longitudinal direction previously mentioned and as illustrated by way of example in FIG. 2.The propagation by successive total reflections of a light ray generated by the additional light source 12 continues in the optical element 2 until it encounters a diffusing element which deflects the path of this ray towards the external face 8 at an angle suitable for being refracted towards the road scene and participating in generating a signaling beam for other road users. The main light source and the additional light source 12 can be powered simultaneously or separately and the power supply of each of the sources is a function of the diffusion state of the controllable liquid crystal screen 18.

[0058] The controllable liquid crystal display 18 may be fixed to the optical element 2 by gluing, with glue that may be arranged between the controllable liquid crystal display 18 and the optical element 2, for example on the periphery of the contact face between the controllable liquid crystal display 18 and the optical element 2, or alternatively be fixed to the optical element 2 by an overmolding operation. This alternative makes it possible to make the controllable liquid crystal display 18 integral with the optical element 2 without inserting glue between the controllable liquid crystal display 18 and the optical element 2 which could have a minimal effect on the propagation of the light rays emitted by the light module through the optical block formed by the controllable liquid crystal display 18 and the optical element 2.

[0059] The controllable liquid crystal screen 18 makes it possible to adjust the diffusion level of the optical block that it helps to form with the optical element 2 to diffuse or not the light beam A caused to pass through this optical block, or to form a diffusing screen opposite an internal face of the optical element 2 and promote the exit towards the road scene in a signaling beam of light rays emitted on the edge of the light guide that this optical element forms.

[0060] For this, the controllable liquid crystal screen 18 is arranged between the light module 4 and the optical element 2 so that it participates in forming a diffusing face of the optical element opposite the road scene when the controllable liquid crystal screen 18 is configured accordingly. It is understood here that in this arrangement, the light beam A is caused to pass through the controllable liquid crystal screen 18 before passing through the optical element 2 when the controllable liquid crystal screen is configured to be transparent to the passage of the light rays.

[0061] According to the invention, the controllable liquid crystal screen 18 is capable of taking different diffusion states, including at least one projection state allowing the projection of the light beam A through the optical unit to form an illumination beam at the output of the optical unit and in which the controllable liquid crystal screen 18 is transparent and a state of emission of a signaling beam in which the controllable liquid crystal screen 18 is non-transparent.

[0062] The projection state of the controllable liquid crystal screen 18 is associated with the emission of the light beam A by the light module and the use of this light beam A to generate a lighting function of the dipped beam type or of the main beam type, while the emission state of the controllable liquid crystal screen 18 is either associated with the emission of the light beam A and its transformation by diffusion or associated with the emission of light rays directly into the light guide formed by the optical element via the implementation of the additional light source.

[0063] These different states of the controllable liquid crystal screen 18 are defined according to the haze, or Haze index, that said controllable liquid crystal screen 18 presents in each of these states, the haze corresponding to the percentage of light rays succeeding in passing through an object that they encounter.

[0064] For example, in the state of projection of a lighting beam, the controllable liquid crystal screen 18 has a diffusion haze of low value, that is to say, for example less than 6%. Advantageously, the diffusion haze of the controllable liquid crystal screen 18 is approximately 3% when said screen 18 is in the projection state.

[0065] Conversely, in the state of emission of a signaling beam, the controllable liquid crystal display has a non-diffusion state, that is to say a diffusion veil of high value, for example of more than 90%.

[0066] Advantageously, the diffusion veil of the controllable liquid crystal screen 18 is approximately 98% when said screen is in the emission state.

[0067] The modification of the diffusion veil of the controllable liquid crystal screen 18 is carried out by a modification of the electrical power supply of this screen, which has the effect of modifying the orientation of the liquid crystals within the screen and making it possible to generate more or less deviation of the light rays passing through the screen by these liquid crystals.

[0068] More particularly, the controllable liquid crystal screen 18 comprises two transparent walls 20, 22 and a polymer matrix 24 in which liquid crystals are randomly dispersed and which extends between the two transparent walls 20, 22. The controllable liquid crystal screen also comprises electrodes connected respectively to each of the transparent walls 20, 22 to allow the passage of electric current within the controllable liquid crystal screen, and more precisely to allow the passage of current from one transparent wall to the other through the polymer matrix.Each of the walls may in particular comprise two layers stacked on top of each other, with a current-conducting layer, for example formed of indium tin oxide (ITO), directly in contact with the polymer matrix, and an electrically insulating layer, for example formed of polycarbonate (PC), arranged to cover the conductive layer opposite the polymer matrix.

[0069] The controllable liquid crystal screen 18 comprises more particularly an internal transparent wall 20 facing the light module 4 and an external transparent wall 22 facing the external medium of the lighting and signaling device 1, the optical element 2 being against the external transparent wall 22. Where appropriate, if the manufacturing means allow it, the optical element 2 can form the external transparent wall 22 and more particularly the electrically insulating layer of this external transparent wall.

[0070] The lighting and signaling device 1 comprises a control member 28 of the controllable liquid crystal screen 18 intended to control the electrical supply of the controllable liquid crystal screen 18 via the electrodes and a power cable 26 shown schematically in the figures. The control member 28 is configured to electrically supply the controllable liquid crystal screen 18, and more particularly the polymer matrix 24 and the liquid crystals which are embedded therein and dispersed randomly at the origin, so as to orient the liquid crystals in a direction parallel to the main direction of the current within the polymer matrix when the screen is powered and thus limit the impact of the liquid crystals on the path of the light rays.It is understood that an electrical supply to the controllable liquid crystal screen 18 results in an arrangement of the liquid crystals which causes the screen to pass from a diffusing state to a transparent state, that is to say here from a state of emission of a signaling beam to a state of projection of a lighting beam.

[0071] If necessary, intermediate states can be given to the controllable liquid crystal screen 18 by adjusting the intensity of the electric current passed through the polymer matrix.

[0072] More particularly, the initial state of the controllable liquid crystal screen 18 is the diffusing state, which corresponds to the state of the controllable liquid crystal screen 18 when the polymer matrix 24 and the liquid crystals embedded therein are not electrically powered and the arrangement of the liquid crystals remains random, such that the light rays brought to meet and / or pass through the screen and the optical block that it helps to form are reflected and refracted and emerge in the diffuse state.

[0073] As soon as the control member 28 transmits an electrical power supply to the polymer matrix 24, in particular via the electrodes and the cable 26, the liquid crystals organize themselves among themselves, in particular by aligning themselves perpendicularly with respect to the transparent walls carrying the electrodes, so that the controllable liquid crystal screen passes into a projection state, the light beam A then being able to pass through the controllable liquid crystal screen 18 in the direction of the optical element 2 in order to be able to form a regulatory lighting beam on the road scene.

[0074] These two different diffusion states are notably visible in Figures 1 to 3, on which a controllable liquid crystal screen 18 is illustrated partly transparent and partly non-transparent in Figure 1, and entirely in a non-transparent state in Figures 2 and 3.

[0075] Several embodiments of the invention will now be described, including a first embodiment illustrated in Figures 1 to 3, a second embodiment illustrated in Figure 4, and a third embodiment illustrated in Figure 5. Each of the embodiments that will be described can be carried out alternatively or in addition to one or more other embodiments, unless otherwise stated. In addition, the objects common to the different embodiments and to what has been described previously will have the same references in each of the descriptions of the embodiments that follow.

[0076] In a first embodiment of the invention, and as more particularly visible in figures 1 to 3, the controllable liquid crystal screen 18 comprises a first portion 30 and a second portion 32 extending at the periphery of the first portion 30, the diffusion state of one of the portions being independent of the diffusion state of the other portion. In other words, the first portion 30 is electrically powered by the control member 28 independently of the second portion 32 so that depending on the use cases, an electrical power supply of the same intensity can be sent to both portions simultaneously or one of the two portions, in particular the second portion 32, may not be powered while the first portion is.

[0077] The second portion 32 can in particular be made electrically independent of the first portion 30 by laser cutting of the surface of the transparent walls, which allows a separate electrical supply for each of the two portions.

[0078] The second portion 32 is formed on the periphery of the screen over a dimension such that the light beam A emitted by the light module 4 is projected onto the controllable liquid crystal screen 18 essentially or entirely onto the first portion 30.

[0079] For example, in a first configuration illustrated in FIG. 1, the first portion 30 of the controllable liquid crystal screen 18 is electrically powered to orient the liquid crystals in the direction of the current flowing within the polymer matrix, such that this first portion 30 is in a state of projection of an illumination beam, i.e. with high transparency. And in this first configuration, the second portion 32 of the controllable liquid crystal screen is not electrically powered so that the liquid crystals remain randomly dispersed within the polymer matrix of this second portion 32 and this second portion is in a state of emission of a light beam, i.e. a diffusing state, with low transparency.

[0080] In this first configuration, the light beam A emitted by the light module is projected through the first portion 30 of the controllable liquid crystal screen 18, and it is understood that the first portion 30 of the controllable liquid crystal screen 18 and the optical element 2 form an assembly which does not deflect the light beam A, so that the lighting function of the light module, whether it is a dipped beam or main beam function, is not impacted by the presence of the controllable liquid crystal screen 18 and can comply with regulatory standards.

[0081] It is also possible to provide for the emission of light rays by the additional light source in order to improve the uniformity of appearance of the lighting and signaling device.

[0082] According to a second configuration illustrated in Figure 2, the first portion and the second portion of the controllable liquid crystal screen 18 are each in a diffusing state, i.e. a signaling beam emission state. Neither the first portion 30 nor the second portion 32 of the controllable liquid crystal screen 18 are electrically powered by the control member 28 so that the liquid crystals present in each of these portions remain in their original position, i.e. randomly dispersed in the polymer matrix, in different orientations from each other. In this second configuration, the light module 4 is inactive so that no light beam seeks to pass through the optical block formed by the controllable liquid crystal screen 18 and the optical element 2. No lighting function is provided by the lighting and signaling device 1 of the invention.

[0083] Conversely, the additional light source 12 arranged opposite a slice of the optical element 2 is activated so as to emit light rays in the thickness of the optical element. As mentioned previously and visible in FIG. 2, the light rays are brought to encounter a diffusing element, formed by the diffusing state of the controllable liquid crystal screen 18 pressed against the internal face 10 of the optical element 2, and they are then deflected to be directed opposite the external face 8 with an angle allowing their diffraction outside the optical element, to form a signaling beam.

[0084] The diffusing state of the controllable liquid crystal screen 18 participates in generating a signaling beam, via the activation of the additional light source, so that this diffusing state corresponds as mentioned to a state of emission of a signaling beam.

[0085] It is also possible to provide that the light module projects a light beam in order to make the diffusion of the light rays even more homogeneous.

[0086] According to a third configuration illustrated in Figure 3, the first portion 30 and the second portion 32 of the controllable liquid crystal screen 18 are also in a diffusing state. This third configuration differs in particular from the second configuration in that the light module is active, so that a light beam A is caused to pass through the first portion 30, now diffusing unlike the first configuration of Figure 1, of the controllable liquid crystal screen 18. The light beam A is thus deflected and made diffuse by the random arrangement of the liquid crystals to form a signaling beam at the output of the lighting and signaling device of the invention.

[0087] According to an alternative configuration and not shown here, the diffusion of a light beam A emitted by the light module and the diffusion of light rays emitted by the additional light source can be combined to increase the intensity of a signaling beam generated by the lighting and signaling device.

[0088] Furthermore, in either configuration, the diffusion veil of the controllable liquid crystal screen 18 can take intermediate values, in particular by varying the intensity of the electrical power supply from one configuration to another. The intensity of the electrical power supply can also vary depending on the concentration of liquid crystals dispersed in the polymer matrix.

[0089] Alternatively, it could also be provided that only the second portion 32 is powered, while the first portion 30 is not. It is therefore understood that the first portion 30 is in a transmission state while the second portion 32 is in a projection state.

[0090] It can also be provided that the first portion 30 and the second portion 32 are each electrically powered, each of the portions then being in a projection state.

[0091] According to a second embodiment of the invention, and as visible in Figure 4, the lighting and signaling device 1 comprises a diffusion element 34 for light rays arranged opposite the second portion 32 of the controllable liquid crystal screen 18. For example, the diffusion element 34 is a film installed between the controllable liquid crystal screen 18 and the optical element 2, the film of the diffusion element 34 for light rays extending at the periphery of the optical element so that the light rays propagating by successive reflections within the optical element and encountering this diffusing film are caused to be deflected and subsequently encounter the external face 8, or exit face, of the optical element at an angle such that they can be refracted to exit the optical element and form a signaling beam, towards the external environment of the lighting and signaling device 1.

[0092] It can thus be defined that the optical element 2 comprises a main zone facing the first portion 30 of the controllable liquid crystal screen 18 and a zone peripheral to the main zone facing the second portion 32, the diffusion element 34 constituting the peripheral zone of the optical element 2. It is understood that the diffusion element 34 is an integral part of the optical element 2 and can form for example a graining pattern at the periphery of the optical element 2 in order to diffuse the light rays passing through the optical element 2 at its periphery.

[0093] It should be noted that the presence of a diffusion element 34 on the periphery of the optical element 2 is not incompatible with the different configurations mentioned previously with reference to the first embodiment.

[0094] According to a third embodiment, and as visible in Figure 5, the lighting and signaling device 1 comprises a masking member 36 arranged to cover the periphery of the external face 8 of the optical element 2. For example, masking member 36 means a wall extending from the housing 6 opposite the external face 8 of the optical element 2 and which covers at least the periphery of the optical element 2. The wall can thus have a particular profile, cutting out the contours of the signaling beams emitted by the lighting and signaling device i according to the invention, and thus ensuring a recognizable visual identity of the vehicle.

[0095] Here again, it should be noted that the presence of a masking member 36 on the periphery of the optical element 2 is not incompatible with the different configurations mentioned previously with reference to the first embodiment.

[0096] As a reminder, the invention relates to a lighting and signaling device comprising a light module and a controllable liquid crystal screen capable of assuming different diffusion states and arranged across a direction of emission of a light beam emitted by this light module, the different diffusion states of the controllable liquid crystal screen being defined by an appropriate electrical power supply depending on the need to emit a lighting beam which must not or only slightly be deflected at the output of the light module or the need to emit a signaling beam. The invention is thus particularly advantageous in that it makes it possible to use the same lighting surface for each of the lighting and signaling functions fulfilled by the lighting and signaling device, without hindering the regulatory projection of a lighting beam.

[0097] The present invention cannot, however, be limited to the means and configurations described and illustrated here and it also extends to any equivalent means and configuration as well as to any technically effective combination of such means.

Claims

CLAIMS 1. Lighting and signaling device (1) comprising at least one light module (4) capable of generating a lighting beam (A) along a longitudinal optical axis and an optical element (2) through which the lighting beam (A) is projected, characterized in that the lighting and signaling device (1) comprises a controllable liquid crystal screen (18) pressed against the optical element (2), the controllable liquid crystal screen (18) being capable of taking different diffusion states including at least one projection state of the lighting beam (A) in which the controllable liquid crystal screen (18) is transparent and a emission state of a signaling beam in which the controllable liquid crystal screen (18) is at least partially diffusing.

2. Lighting and signaling device (1) according to the preceding claim, in which the controllable liquid crystal screen (18) comprises two transparent walls (20, 22), a polymer matrix (24) extending between the two transparent walls (20, 22) and in which liquid crystals are dispersed, and two electrodes associated respectively with one of the transparent walls.

3. Lighting and signaling device (1) according to any one of the preceding claims, comprising a control member (28) of the controllable liquid crystal screen (18) configured to electrically power the controllable liquid crystal screen (18) so that the controllable liquid crystal screen (18) changes from a projection state to a state of emission of a signaling beam and vice versa depending on a modification of the electrical power supply.

4. Lighting and signaling device (1) according to any one of the preceding claims, comprising a main light source constituting the light module (4) and an additional light source (12) installed opposite the optical element (2).

5. Lighting and signaling device (1) according to the preceding claim, in which the optical element (2) has an internal face (10) in contact with the controllable liquid crystal screen (18), an opposite external face (8) and a peripheral edge connecting the internal face (10) to the external face (8), the additional light source (12) being installed opposite the peripheral edge of the optical element (2).

6. Lighting and signaling device (1) according to any one of the preceding claims, in which the controllable liquid crystal screen (18) comprises a first portion (30) and a second portion (32) extending at the periphery of the first portion (30), the diffusion state of one of the portions of the controllable liquid crystal screen (18) being independent of the diffusion state of the other of said portions.

7. Lighting and signaling device (1) according to the preceding claim in combination with claim 3, in which the first portion (30) is electrically powered by the control member (28) independently of the second portion (32).

8. Lighting and signaling device (1) according to any one of claims 6 or 7, comprising a diffusion element (34) for light rays arranged opposite the second portion (32) of the controllable liquid crystal screen (18).

9. Lighting and signaling device (1) according to any one of claims 6 to 8, comprising a masking member (36) arranged to cover the periphery of the external face (8) of the optical element (2).

10. Motor vehicle equipped with at least one lighting and signaling device (1) characterized according to any one of the preceding claims.

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