FR3053758A1 - LIGHTING AND / OR SIGNALING DEVICE FOR MOTOR VEHICLE - Google Patents

Abstract

A semiconductor light source (1) comprises a plurality of submillimeter-sized electroluminescent rods (8) from which at least two selectively activatable regions (4, 6) formed by a plurality of rods can be distinguished. A first (4) of the at least two zones is configured to transmit in a first transmission mode while a second (6) of the at least two zones is configured to transmit according to two transmission modes.

Description

© Publication number: 3,053,758 (to be used only for reproduction orders) (© National registration number: 16 56389 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY

COURBEVOIE © IntCI ⁸ : F 21 K 9/00 (2017.01), H 05 B 33/08, F 21 Y 107/00

A1 PATENT APPLICATION

(© Date of filing: 05.07.16. (© Applicant (s): VALEO VISION Joint-stock company (© Priority: simplified - FR. @ Inventor (s): ALBOU PIERRE. ©) Date of public availability of the request: 12.01.18 Bulletin 18/02. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents (73) Holder (s): VALEO VISION Joint stock company related: folded. ©) Extension request (s): (© Agent (s): VALEO VISION Limited company.

Y> 4 / LIGHTING AND / OR SIGNALING DEVICE FOR A MOTOR VEHICLE.

FR 3 053 758 - A1

A semiconductor light source (1) comprises a plurality of light-emitting rods (8) of submillimetric dimensions, among which at least two selectively activatable zones (4, 6) formed by a plurality of rods can be distinguished.

A first (4) of the at least two zones is configured to transmit according to a first transmission mode while a second (6) of the at least two zones is configured to transmit according to two transmission modes.

i

LIGHTING AND / OR SIGNALING DEVICE FOR

MOTOR VEHICLE

The invention relates to the field of lighting and / or signaling, in particular for motor vehicles. It relates more particularly to a lighting and / or signaling device configured to project an at least partially pixelated light beam, capable of integrating visual information projected in front of or behind the vehicle.

A motor vehicle is equipped with headlights, or headlights, intended to illuminate the road in front of the vehicle, at night or in the event of reduced light, by a global light beam. These projectors, a left projector and a right projector, respectively comprise one or more light modules adapted to generate and direct an intermediate light beam, the addition of which forms said global light beam.

Up to now, headlamps are commonly fitted with light modules capable of generating in particular a road beam, which makes it possible to strongly illuminate the road far in front of the vehicle, and a code beam, or passing beam, which provides more limited lighting. of the road, but nevertheless offering good visibility, without dazzling other road users. The headlights can be fitted with other modules to generate, for example, a lighting beam for foggy weather, or a signaling beam of the DRL (Daytime Running Ligbt, or daytime running light) type.

It is known to produce the Route beam by adding the passing beam and an additional beam, arranged in the vicinity of the passing beam, possibly with a thin overlap, at a cut edge whose definition allows, when the passing beam is used alone, do not dazzle other users. The passing beam is generated by the sole ignition of specific means while the Road beam is generated by the simultaneous ignition of means specific to the passing beam and means specific to the first mode "main beam". In a headlamp, a distinction is made between Route modules and Code modules generating the low beam.

In addition to these regulatory lighting functions, essential for the safety of all road users, automobile manufacturers and equipment manufacturers aim to offer devices that facilitate driving and in particular the presentation of information relating to the condition of the vehicle, the detection of an emergency situation or the presentation of navigation information. Information projection devices on the windshield have for example been developed, in order to avoid the driver having to look away from the road scene to view this information.

The present invention is part of this signaling device aimed at projecting navigation and / or (dis) operation information of the vehicle, by not targeting a projection on the windshield, only intended for the driver of the vehicle, but more generally on the road scene, downstream of the vehicle relative to its direction of travel when it is information to be viewed by the occupants of the vehicle or downstream of the vehicle when it is information to be viewed by the occupants of a following vehicle. The information to be displayed advantageously has a pictogram form, which is simple to understand, and for example an arrow when the satellite navigation device associated with the vehicle detects an upcoming turn, or an exclamation point when an emergency situation arises. involves rapid immobilization of the vehicle, etc.

For this purpose, it is known to superimpose an additional beam on the main beam, whether this main beam corresponds to a passing beam or to a road beam, to create in this additional beam an image which one wishes to project.

By way of example, in FIG. 1, an example of a pixelated image projection application on the ground downstream of a motor vehicle has been illustrated, in which an aim is to project an indication on the route to be followed by the driver. A main beam 100 is projected downstream of the vehicle, in the direction of travel of the vehicle, in order to legally illuminate the road scene. An additional beam 102 is projected into an area of this main beam, and a pixelated image 104 is created in this additional beam. In the illustrated case, a dark area is formed inside the additional beam 102 to take the form of an arrow, so that this pictogram is cut out from the additional beam and visible to the driver. In order to obtain a particularly visible image, an optimal contrast is re-embedded between the dark part forming the pictogram and the rest of the additional beam. It is therefore necessary to have a large light intensity of the additional beam. A first problem thus resides in the necessary contrast between the pictogram and the rest of the beam. There is in particular a problem of contrast during the day or at night when headlights from third-party vehicles illuminate the dark area. The problem is the same when you want to project highlighted information, that is to say that the pictogram is not produced in negative in an additional beam but by a light overcurrent compared to the rest of the additional beam. . We understand that here again we need a strong luminance.

In motor vehicles, light sources are more and more frequently constituted by light-emitting diodes, in particular for advantages of space and autonomy compared to conventional light sources. The use of light-emitting diodes in the light modules of motor vehicles has also enabled market players (automobile manufacturer and designer of light devices) to bring a creative touch to the design of these devices, in particular through the use an ever greater number of these light-emitting diodes to achieve optical effects. However, their application in the context described above does not make it possible to create a light intensity sufficiently powerful for the outside observer and / or the occupant of the vehicle to clearly discern the inscriptions projected on the ground.

It has been envisaged to solve this problem of light intensity the use of a class IV laser, of red color, whose projection of the ray on the ground is ensured via an electromechanical microsystem, that is to say mirrors rotary, MEMS type. The use of a laser makes it possible to have a strong luminance and the use of color facilitates the perception by the eye of the information written on the ground. The projection on the ground aims to avoid contact with the eyes of an outside observer but it is understood that the use of such a laser presents a risk, for example in the case where the micro mirrors are deficient and that the ray emitted by the laser source points towards the horizon, or else in the case where the projected beam meets in particular on the ground a poorly oriented reflecting element.

At the same time, a second problem lies in the homogeneity of the projected global beam. The light rays forming the additional beam are emitted from a light module distinct from the light module from which the light rays forming the passing beam are emitted. As a result, as can be seen in FIG. 1, this results in a discontinuity of the overall beam emitted at the level of the overlap of the main beam by the additional beam.

The invention aims to propose an alternative to the use of the different light sources as they have just been presented. In this context, the subject of the invention is a semiconductor light source comprising a plurality of electroluminescent rods of submillimetric dimensions among which one can distinguish at least two activatable zones selectively formed by a plurality of rods, a first of at least two zones being configured to transmit in a first transmission mode while a second of the at least two zones is configured to transmit in two transmission modes.

Thus, it is possible to mark information in the emission zone produced by the second of the at least two zones. The first of at least two zones transmits a first intermediate beam, of a first color and / or of a first intensity, while the second of at least two zones transmits a second beam intermediate, this second intermediate beam possibly being complementary to the first intermediate beam, for example of the same first color and / or of the same first intensity, or else take the form of a pixelated beam in which some of the pixels of the second intermediate beam are produced differently other pixels of this second intermediate beam. A pixel is formed by the smallest selectively activatable unit, namely one or more neighboring rods.

Advantageously, the sticks have been grouped into addressable or activatable areas selectively, rather than providing for selective addressing of each of the sticks. This makes it possible to limit the electrical connection elements to be provided and this also makes it possible to be able to continue to project information on the ground when one of the sticks is deficient.

According to different characteristics of the invention, taken alone or in combination, it can be provided that:

the second of the at least two rod areas is configured to transmit according to at least the first transmission mode;

the first rod area is configured to emit a first intermediate beam in which is registered a second intermediate beam emitted by the second rod zone;

the second of the at least two areas is formed of at least one pixel composed of a plurality of selectively activatable sticks.

A first zone may comprise at least a first pixel, capable of fulfilling a pbotometric function, while the second of at least two zones may comprise at least a second pixel, capable of completing the photometric function when the second pixel is arranged according to a first configuration and able to display information when the second pixel is arranged in a second configuration. It is understood that the information displayed is more precise as soon as the second zone comprises a plurality of selectively addressable pixels.

According to a particular embodiment of the invention, it can be provided that a first part of the plurality of rods of a pixel is configured to emit light according to a first wavelength while a second part of the plurality rods of this pixel is configured to emit light at a second wavelength.

Alternatively, or in addition to the above, it may be provided in another zone of the light source, that a first and a second part of the plurality of rods of one pixel are configured to emit light of the same length. wave, with distinct light intensities.

Alternatively, the plurality of rods of a pixel may be capable of emitting light of the same wavelength, and a device is provided for converting wavelengths into overlapping, or at least in the vicinity, of the rods and which is able to process the light emitted only by a first part of the plurality of rods of a pixel. In particular, provision may be made to deposit on the rods of this pixel a layer of material comprising phosphors forming a wavelength conversion means and to cut out this layer of material to release the second part of the rods.

It can be provided that the second of the at least two zones comprises a plurality of pixels, that the number of sticks present in each pixel being the same from one pixel to the other, and that the number of sticks in each first part is equal from one pixel to another.

According to a characteristic of the invention, the second zone of the at least two rod zones can be arranged from an edge of the light source. It is thus possible to arrange the second zone of rods so that the second intermediate beam which it projects, that is to say the zone in which the information will be projected, is arranged in the lower part of the beam. In the case where the light source directly emits its light rays towards a lens forming the projection optics, in direct imaging, the second zone will thus be arranged in the upper part of the light source so that the second intermediate beam in which is carried the information and corresponding to this second area is at the bottom of the global beam. We can thus provide an information writing area that is close to the car. According to the embodiments and the extent of this second zone of rods along the edge of the light source, a second narrow zone may be provided which allows the projection of static information, or a second wider zone, up to 'to extend over the entire length of the source, which allows the projection of dynamic information. By dynamic information, we understand information that can change as the vehicle advances, by modifying the ignition of the sticks making up the pixels of this second area.

The light-emitting sticks can extend from the same substrate, and they can in particular be formed directly on this substrate. Provision may be made for the substrate to be based on silicon or on silicon carbide. It is understood that the substrate is based on silicon since it mainly comprises silicon, for example at least 50% and in practice about 99%.

According to a series of characteristics of the invention, taken alone or in combination, it can be provided that:

- an integrated electronic circuit is disposed on the substrate, on the face opposite to the face from which the rods extend, said integrated circuit being configured to control the selective activation of the rod zones, and of the pixels which can compose each of these areas;

- The integrated electronic circuit is advantageously soldered below the substrate, and in a step subsequent to that of growth of the sticks;

- the electronic circuit is configured to transform, via an associated decoder, information of the image to be displayed sent by a control module into control instructions for feeding the sticks; it is understood that the information of the image to be displayed can consist of a sending of all the bits to be respected, that is to say of all the switching on / off actions of each of the sticks or of each of the groups of sticks, or it can consist of a reference number of a particular form of the image, the electronic circuit then being configured to draw from a database the states of the sticks to be instructed to achieve this particular form of the image ;

- the integrated electronic circuit includes a static memory, so that the rod control power supply information remains as it is until the integrated electronic circuit sends contrary control information.

According to the characteristics of the invention, taken alone or in combination with other characteristics of the invention, provision may be made for:

- Each rod has a generally cylindrical shape, in particular of polygonal section; we can provide that each stick is the same general shape, and in particular a hexagonal shape;

- the rods are each delimited by a terminal face and by a circumferential wall which extends along a longitudinal axis of the rod defining its height, the light being emitted at least from the circumferential wall; this light could also be emitted by the terminal face;

- Each rod may have an end face which is substantially perpendicular to the circumferential wall, and in different variants, it can be provided that this end face is substantially planar or curved, or pointed, at its center;

- the rods are arranged in a matrix, whether this matrix is regular, with constant spacing between two successive rods of a given alignment, or that the rods are staggered;

- the height of a stick is between 1 and 10 micrometers;

- the largest dimension of the terminal face is less than 2 micrometers;

- the distance between two immediately adjacent rods is at least equal to 2 micrometers, and at most equal to 100 micrometers.

According to other characteristics, provision may be made for the semiconductor light source comprising a plurality of electroluminescent rods of submillimetric dimensions to further comprise a layer of polymeric material in which the rods are at least partially embedded; this polymeric material can be based on silicone, it being understood that the polymeric material is based on silicone since it mainly comprises silicone, for example at least 50% and in practice about 99%. As may have been specified previously, the layer of polymeric material may comprise a phosphor or a plurality of phosphors excited by the light generated by at least one of the plurality of rods and forming wavelength conversion means. A phosphor or light converter is understood to mean the presence of at least one luminescent material designed to absorb at least part of at least one excitation light emitted by a light source and to convert at least part of said light. of excitation absorbed in emission light having a wavelength different from that of the excitation light. This phosphor, or this plurality of phosphors, can be at least partially embedded in the polymer, or else placed on the surface of the layer of polymeric material.

The invention also relates to a light module for a motor vehicle comprising a light source as previously described and an optical system for projecting the light generated by the light source.

According to the invention, the projection optics creates a real, and possibly anamorphic image, of a part of the device, for example the source itself or a mask, or of an intermediate image of the source, at a distance ( finite or infinite) very large compared to the dimensions of the device (of a ratio of the order of at least 30, preferably 100) of the device. This projection optic can consist of one or more reflectors, or else a lens, or even a combination of these two possibilities.

The invention also relates to a lighting and / or signaling device comprising a housing for receiving at least one light module as it has just been presented.

This device can include a system for detecting external conditions and / or the projected image to control in real time the emission modes of the rod zones. The detection system may in particular consist of a sensor detecting ambient light, or of a camera associated with image processing means.

In such a lighting device, the two rod zones define an illuminating surface of the light source whose peripheral edge defines a contour of the light beam projected by the device.

As just described, the device takes place in a motor vehicle, and in particular in a headlight, configured to emit at least one passing beam.

A technology is therefore applied according to the invention to the automotive field, consisting in producing the light-emitting zone by a plurality of light-emitting sticks of submillimetric dimensions which are grown on a substrate, in order to produce a three-dimensional topology. It is understood that this three-dimensional topology has the advantage of multiplying the light emission surface compared to the light-emitting diodes known hitherto in the automotive field, namely substantially planar diodes. And here it allows, by an adequate electronic connection of the sticks, to propose on a specific zone of the source of the tangled parts which can be activated selectively to produce a pixelated lighting, in particular colored, allowing the projection of information outside the vehicle with sufficient of contrast.

Other characteristics and advantages of the present invention will appear more clearly with the aid of the description and the drawings, among which:

- Figure 1 illustrates an example of application of pixelated image projection on the ground downstream of a motor vehicle, in which it is intended to project an indication on the road to be followed by the driver, according to an embodiment of the art anterior;

- Figure 2 is a sectional view of a device according to the invention, in which there is illustrated a semiconductor light source comprising electroluminescent rods, said rods not being shown to scale in order to make it visible, said source being oriented so that the rays emitted by the rods are directly directed towards an optic for shaping the rays;

- Figure 3 is a schematic perspective representation of a semiconductor light source according to an embodiment of the invention, said light source comprising a plurality of light-emitting sticks among which a row has been made visible in section of these light-emitting sticks;

FIG. 4 is a diagrammatic illustration of an array of light-emitting rods forming the light source according to the invention on which the region in which the pixels are arranged is shown so that they emit according to two emission modes in accordance with the present invention;

- Figure 5 is a schematic representation of a particular arrangement of light-emitting sticks for a pixel arranged in the region identified in Figure 4;

- Figure 6 is a sectional view of a particular embodiment of the invention, in which two light-emitting sticks project from a substrate, said light-emitting sticks being encapsulated in a protective layer;

- Figure 7 is a view similar to that of Figure 5, in which the protective layer is arranged above the sticks, a cut of this protective layer leaving a part of the sticks of the pixel free; and

- Figure 8 illustrates an example of application of pixelated image projection on the ground downstream of a motor vehicle, in which it is intended to project an indication on the route to be followed by the driver, according to the present invention.

A lighting and / or signaling device of a motor vehicle comprises a light source 1, in particular housed in a housing closed by a crystal and which defines an internal volume for receiving this light source associated with projection optics 2 ίο suitable for infinitely imaging the light source by deflecting at least part of the light rays emitted by the light source.

In FIG. 1, the light source 1 is centered on the optical axis 3 of the converging lens forming the projection optics 2 adapted to image the light source outside the vehicle. The light source 1 is oriented so that the rays it emits are directed directly towards the lens. For reasons of space requirement of the light device for example, it may be provided that the light source does not emit mainly in the direction of the optical axis of the lens, but substantially perpendicular to it, and that the rays are deflected by an optical means of the paraboloidal or ellipsoidal reflector type.

The light source 1 according to the invention comprises a plurality of light-emitting rods 8, of submillimetric dimensions, arranged in a plurality of zones, among which at least a first zone 4 and a second zone 6 (as visible in FIG. 4) .

We will first describe the structure of a semiconductor light source 1 comprising light-emitting sticks of submillimetric dimensions, in particular with reference to FIG. 3.

The light source 1 comprises a plurality of electroluminescent rods 8 which originate on at least one substrate 10. Each electroluminescent rod, here formed by the use of gallium nitride (GaN), extends perpendicularly, or substantially perpendicularly, projecting from the substrate, here produced on the basis of silicon, other materials such as silicon carbide which can be used without departing from the context of the invention. For example, the light-emitting sticks could be made from an alloy of aluminum nitride and gallium nitride (AlGaN), or from an alloy of aluminum, indium and gallium ( AllnGaN).

The substrate 10 has a lower face 12, on which a first electrode 14 is attached, and an upper face 16, projecting from which extend the light-emitting rods 8 and on which a second electrode 18 is attached. Different layers of materials are superimposed on the upper face 16, in particular after the growth of the light-emitting rods from the substrate here obtained by a bottom-up approach. Among these different layers, one can find at least one layer of electrically conductive material, in order to allow the electrical supply of the rods. This layer is etched so as to connect such and such a stick to each other, the lighting of these light-emitting sticks can then be controlled simultaneously by a control module not shown here. Provision may be made for at least two light-emitting sticks or at least two groups of light-emitting sticks to be arranged to be ignited separately by means of an ignition control system.

The light-emitting rods stretch from the substrate and, as can be seen in FIG. 3, they each comprise a core 19 of gallium nitride, around which are arranged quantum wells 20 formed by a radial superposition of layers of different materials , here gallium nitride and gallium-indium nitride, and a shell 21 surrounding the quantum wells also made of gallium nitride.

Each electroluminescent rod extends along a longitudinal axis 22 defining its height, the base of each rod being disposed in a plane 24 of the upper face 16 of the substrate 10.

The light-emitting sticks 8 of the same light source advantageously have the same shape. They are each delimited by an end face 26 and by a circumferential wall 28 which extends along the longitudinal axis. When the light-emitting rods are doped and are the subject of a polarization, the resulting light at the output of the semiconductor source is emitted essentially from the circumferential wall 28, it being understood that light rays can also come out of the end face 26. As a result, each light-emitting stick acts as a single light-emitting diode and the luminance of this source is improved on the one hand by the density of the light-emitting sticks 8 present and on the other hand by the size of the illuminating surface defined by the circumferential wall and which therefore extends over the entire periphery, and the entire height, of the rod.

The circumferential wall 28 of an electroluminescent rod 8, corresponding to the gallium nitride shell, is covered by a layer of transparent conductive oxide (OCT) 29 which forms the anode of each rod complementary to the cathode formed by the substrate . This circumferential wall 28 extends along the longitudinal axis 22 from the substrate 10 to the end face 26, the distance from the end face 26 to the upper face 16 of the substrate, from which the light-emitting rods 8 arise. , defining the height of each stick. By way of example, it is provided that the height of an electroluminescent rod 8 is between 1 and 10 micrometers, while provision is made for the greatest transverse dimension of the terminal face, perpendicular to the longitudinal axis 22 of the rod concerned, ie less than 2 micrometers. It is also possible to provide for defining the surface of a rod, in a cutting plane perpendicular to this longitudinal axis 22, within a range of determined values, and in particular between 1.96 and 4 square micrometers.

It is understood that during the formation of the light-emitting rods 8, the height can be modified from one zone of the light source to another, so as to increase the luminance of the corresponding zone when the average height of the rods constituting it is increased. Thus, a group of light-emitting sticks can have a height, or heights, different from another group of light-emitting sticks, these two groups being constitutive of the same semiconductor light source comprising light-emitting sticks of submillimetric dimensions.

The shape of the light-emitting sticks 8 can also vary from one device to another, in particular on the section of the sticks and on the shape of the end face 26. The sticks have a generally cylindrical shape, and they can in particular, such as illustrated in FIG. 3, present a shape of polygonal, and more particularly hexagonal, section. We understand that it is important that light can be emitted through the circumferential wall, whether it has a polygonal or circular shape.

Furthermore, the end face 26 may have a substantially planar shape and perpendicular to the circumferential wall, so that it extends substantially parallel to the upper face 16 of the substrate 10, as illustrated in FIG. 3, or although it may have a domed or pointed shape at its center, so as to multiply the directions of emission of the light exiting from this terminal face, as illustrated in FIG. 6.

The light-emitting sticks 8 are arranged in a two-dimensional matrix. This arrangement could be such that the sticks are staggered. Generally, the rods are arranged at regular intervals on the substrate 10 and the separation distance of two immediately adjacent light-emitting rods, in each of the dimensions of the matrix, must be at least equal to 2 micrometers, so that the light emitted by the circumferential wall 28 of each rod 8 can exit from the matrix of light-emitting rods. Furthermore, it is expected that these separation distances, measured between two longitudinal axes 22 of adjacent rods, will not be greater than 100 micrometers.

The semiconductor light source 1 can further comprise, as illustrated in FIG. 3, a layer 30 of a polymeric material in which the light-emitting rods 8 are at least partially embedded. The layer 30 can thus extend over the entire extent of the substrate or only around a determined group of light-emitting sticks 8. The polymer material, which may in particular be based on silicone, creates a protective layer which makes it possible to protect the light emitting sticks 8 without interfering with the diffusion of light rays. In addition, it is possible to integrate in this layer 30 of polymeric material wavelength conversion means, and for example phosphors 3b capable of absorbing at least part of the rays emitted by one of the rods and at converting at least part of said absorbed excitation light into emission light having a wavelength different from that of the excitation light. It is equally possible to provide that the wavelength conversion means are embedded in the mass of the polymer material, or that they are arranged on the surface of the layer of this polymer material.

The light source may further comprise a coating 32 of light-reflecting material which is disposed between the light-emitting rods 8 to deflect the rays, initially oriented towards the substrate, towards the end face 26 of the light-emitting rods 8. In other words , the upper face 16 of the substrate 10 may include a reflecting means which returns the light rays, initially oriented towards the upper face 16, towards the exit face of the light source. We thus recover rays that would otherwise be lost. This coating 32 is disposed between the light-emitting rods 8 on the transparent conductive oxide layer 29.

According to the invention, the light source 1 has light emitting sticks arranged and configured to form selectively activatable zones 4,6 formed by a plurality of rods, a first of the at least two zones being configured to emit according to a first mode of transmission while a second of the at least two zones is configured to transmit in two transmission modes.

In FIG. 3, the light source generally has a rectangular shape, but it will be understood that it can have, without going beyond the context of the invention, other general shapes, and in particular a shape of parallelogram. And that according to the invention, the light-emitting sticks can extend projecting from the substrate according to a determined configuration, or can be connected or not to define a lighting surface that is not necessarily rectangular.

The first zone 4 comprises a plurality of first pixels 40 and it extends substantially over the entire surface of the light source with the exception of a second complementary zone 6. The light-emitting sticks 8 forming the first pixels 40 of the first zone 4 are configured to emit light of a first type, according to a first emission mode, and for example regulatory white light of a passing beam.

The second zone 6 is included in the first zone 4, or in contact with the latter, and it is understood that the rods 8 disposed on the edge of this second zone are directly adjacent to the rods arranged on the edge of the first zone at each common edge of the two areas of the light source.

The second area 6 is arranged from an edge of the light source, as illustrated in FIG. 4. We wish to project the information in the lower part of the beam, so as not to interfere with the pbotometric function, and in an area close to the vehicle to make it easier for the driver to read the information. To this end, in particular in the case illustrated in FIG. 1, the beam is inverted during projection so that the second zone is arranged along an upper edge 33 of the light source 1, so that the pixels which form this second area to be projected from a lower edge of the beam onto the road.

The rods of this second zone 6 are grouped together to form second pixels 60 which correspond to the smallest entity of the selectively addressable light source. FIG. 5 shows a detail in FIG. 4 relating to a second pixel 60 of the second zone 6.

Each of these second pixels 60 is configured to emit light rays according to two emission modes. One can in particular provide that one of these two emission modes consists of the first emission mode of the first zone 4, namely in the present case of white light example. The other emission mode may consist of an emission of light rays of a determined color, for example red.

In each of the second pixels 60 of this second zone 6, a first part 61 of the rods 8 is configured to transmit according to a transmission mode, advantageously the first transmission mode as just explained, that is to say that is to say rays of white color, and a second part 62 of the rods is configured to emit according to another mode of emission, and for example rays of red color. In the example illustrated, the second part 62 of the sticks takes the form of a fork, but it will be understood that the shape which this second part of the sticks takes can be quite different. It is however interesting that the first part and the second part of the sticks of the same pixel are entangled. By entangled, we mean areas intermingled with one another, which according to the configurations of the corresponding pixel, can be nested or intertwined with one another. In this way, for an outside observer, it appears that the whole pixel changes color when going from the first to the second emission mode, and not just part of the pixel that switches.

If it is understood that the arrangement of the first and second parts can vary from one second pixel to the other, it may be advantageous, for conditions of uniformity of light intensity in particular, for the number of rods present in each pixel to be the same from one pixel to another, and that the number of sticks in each first and second part is equal from one pixel to another.

In a first alternative embodiment, provision may be made for the rods forming a second pixel 60 to be distributed by forming a regular and repetitive series of a stick emitting red, a stick emitting green and a stick emitting blue . In other words, we form a second pixel functioning as an RGB diode. In a first emission mode, all the rods of this second pixel 60 are activated and the additive synthesis of their rays forms a white light, similar to the light emitted by the first pixels 40 of the first zone 4, while in a second mode of emission, some of the rods of this second pixel are deactivated or modified in light intensity to form light of a predetermined color. Such a variant makes it possible to modify the color which it is desired to give to the pixels forming the image to be projected onto the ground. For example, if you want to project an alert warning of an immediate danger, you can turn off in the second adequate pixels, that is to say those forming the pictogram to be projected, the sticks emitting blue and those emitting green, to generate a red pictogram only. In this alternative embodiment, the sticks emitting blue and those emitting green can be defined as the first part of the sticks and the sticks emitting red as the second part of the sticks. Thus, the second zone of the source is configured to transmit according to a first transmission mode, in white, when the first part and the second part of the sticks of the second pixels are activated simultaneously and according to a second transmission mode, here in red, when it is only the second part of the rods of these second pixels that is activated.

In a second alternative embodiment, to be favored in particular when wavelength conversion means are present in the layer of polymeric material placed on the rods, provision may be made for all the rods of a second pixel to be configured to emit the same light color, and that the layer of polymeric material is cut to only partially cover the second pixel 60, and more particularly to cover only the first part of the sticks.

As an example, the sticks of this second pixel can all be configured to emit a blue color. The rays emitted by the first part of the sticks are converted into white light by the phosphors present in the layer of first polymer material and the rays emitted by the second part of the sticks are not converted and remain blue in color. Thus, the second zone of the source is configured to transmit according to a first transmission mode when the first part of the sticks of the second pixels is activated and according to a second transmission mode when it is the second part of the sticks of these second pixels pixels which is activated. A second pixel 60 has been illustrated in FIG. 7 with the cutting edges of the layer of polymer material which makes the rods of this second part clearly visible, the rods of the first part being visible by transparency.

Alternatively, it could be envisaged that the layer of polymer material is not cut, but that the wavelength conversion means are only deposited above the first part of the sticks. Or one could provide colored filters deposited on the layer of material opposite one or the other of the parts of this second pixel, or a layer of different material opposite one or the other of the parts of sticks of the same second pixel.

Whatever the transmission modes chosen, it can be provided that the separation distance between a stick participating in a first zone 4 and a directly adjacent stick and participating in a second zone 6 is substantially equal to the separation distance of two rods from the same area of the light source, this separation distance, measured between two longitudinal axes of electroluminescent rods, being at least 2 micrometers, so that the light emitted by the circumferential wall 28 of each rod 8 can exit the matrix of light-emitting sticks. This results in a continuity of the overall light beam when passing from a first intermediate beam 100, equivalent to the main beam of FIG. 1 and corresponding according to the present invention to the emission by the rods of the first zone to a second intermediate beam 102, equivalent to the intermediate beam of FIG. 2 and corresponding according to the present invention to the emission by the rods of the second zone. This can be seen in particular in Figure 8.

Advantageously, the substrate is common to all of the rods making up the different zones of the semiconductor light source. This optimizes the number of electrical connection wires, and makes it easier to bring the zones of the light source together.

Furthermore, the light source comprises an integrated electronic circuit 34 disposed against the substrate 10, on the underside 12 thereof, that is to say the face opposite to the face from which the rods 8. The integrated electronic circuit is configured to drive the selective activation of the rod zones, of the pixels which can compose each of these zones, and of the first and second parts of rods forming the pixels included in the second rod zone according to the 'invention. The integrated electronic circuit may in particular include communication means configured to exchange with communication means of a control module disposed elsewhere in the housing of the lighting and / or signaling device, or disposed outside the housing .

The control module can be linked to a system for detecting external conditions and / or the projected image to control in real time the emission modes of the rod zones. For example, the control module can compile information according to which the ambient light is high to generate a specific control instruction, intended for the integrated electronic circuit, according to which the second mode of emission of the second rod area must be at strong luminance. It is understood that the detection system mentioned may consist of means for processing images acquired by a camera to define the contrast of the pictogram with respect to the road scene on which it is projected, or may consist of a brightness sensor.

The integrated electronic circuit notably includes a decoder, configured to transform the command instruction into commands for the power supply of each of the addressable sticks. The control module sends an image to the decoder and / or reference indications of the image to be displayed, and the decoder is configured to deduce from this information coming from the control module instructions for switching on and off. for each of the sticks, if necessary by going to dig into databases to match the reference indications with an ignition diagram of the sticks. It is understood that this configuration is given only by way of nonlimiting example and that different types of decoders could be implemented without departing from the context of the invention, for example a JPEG type decoder.

The integrated electronic circuit may include a series of transistors and flip-flops, capable of storing the control information in memory for each addressable stick until the integrated electronic circuit receives a contrary command instruction for this stick.

We will now describe an example of the operating mode of the light source, in order to highlight the function of the characteristics described above.

In a so-called standard driving mode, that is to say a driving mode in which no information is to be projected around the vehicle, the integrated electronic circuit is controlled to light all the sticks likely to participate when a beam is transmitted according to the first transmission mode, in particular for obtaining a Code beam, or even for obtaining a Route beam. By all the sticks capable of emitting according to the first emission mode, is meant all the sticks of the first zone and at least the first part of the sticks of each second pixel of the second zone. In some cases described above, obtaining a beam according to the first emission mode involves lighting all the sticks of the second pixels while in other cases, such a beam is obtained by the sole ignition of the first part of the sticks of each second pixel, the second part of the sticks of each pixel of the second zone then remaining inactive.

When an order instruction is received specifying that a pictogram or any other information must be projected onto the road, the integrated electronic circuit deduces a stick activation command different from the one it had in memory.

In the case where the obtaining by the second zone of a beam according to the first mode of emission passes by the lighting of all the sticks of the second pixels of the second zone, the integrated electronic circuit then proceeds to the extinction of the first part of the sticks, so that only the light emitted by the second part of the sticks persists in the pixels forming the pictogram. This results in a beam emitted by the second pixels different from that emitted by the first pixels in the first zone, which remain unchanged by projecting a beam according to the first emission mode.

In the case where the beam generated by the second zone according to the first emission mode is obtained by the only lighting of the first part of the sticks of each second pixel, the electronic circuit proceeds to the extinction of the first part of the sticks and when the second part of the sticks is lit.

We then write a message or create a pictogram on the ground upstream or downstream of the vehicle. It is understood that the integrated electronic circuit could control the ignition and extinction of the rods within the second zone to produce a dynamic image projection, that is to say a projection which evolves over time for example at as the vehicle progresses. The surface allocated to the second zone should then be large enough, for example by extending over an entire edge of the light source, so that the rods to be activated to form the colored pixels of the pictogram / message can be on a wide range and give the impression that the pictogram formed by the successive lighting of colored pixels is moving.

We could consider playing on the light intensity of the beam according to the second emission mode to accentuate the urgency of the message to convey to the driver or another road user, without modifying the photometric function of the main beam. .

It is understood that the messages may vary and relate both to navigation information and to signaling messages specific to the vehicle and its correct operation, or specific to driving situations and for example the presence of danger in blind spots. .

Claims (15)

1. Semiconductor light source (l) comprising a plurality of light-emitting rods (8) of submillimetric dimensions among which we can distinguish at least two selectively activatable zones (4, 6) formed by a plurality of rods, a first ( 4) at least two zones being configured to transmit in a first transmission mode while a second (6) of the at least two zones is configured to transmit in two transmission modes. 2. Light source according to claim 1, characterized in that the second (6) of the at least two rod areas (8) is configured to emit according to at least the first emission mode. 3. Light source according to claim 1 or 2, characterized in that the first (4) of at least two rod areas is configured to emit a first intermediate beam in which is registered a second intermediate beam emitted by the second (6 ) at least two rod areas. 4. Light source according to one of the preceding claims, characterized in that the second (6) of the at least two zones is formed of at least one pixel (60) composed of a plurality of rods selectively activatable. 5. Light source according to the preceding claim, characterized in that a first part (61) of the plurality of one-pixel sticks (60) of the second zone is configured to emit light according to a first wavelength while a second part (62) of the plurality of rods of this pixel is configured to emit light according to a second wavelength. 6. Light source according to claim 4, characterized in that a first (61) and a second (62) part of the plurality of one-pixel sticks (60) of the second area are configured to emit light of same wavelength, with distinct luminances. 7. Light source according to claim 4, characterized in that the plurality of rods of a pixel (60) of the second zone is capable of emitting light of the same wavelength, and in that a device for wavelength conversion (31) is able to process the light emitted only by a first part (61) of the plurality of rods of a pixel. 8. Light source according to one of claims 4 to 7, characterized in that the second (6) of the at least two zones comprises a plurality of pixels (60), the number of rods (8) present in each pixel being the same from pixel to pixel, 5 and characterized in that the number of sticks in each first part (6l) is equal from one pixel to the other. 9. Light source according to one of the preceding claims, characterized in that the second (6) of the at least two rod areas (8) is arranged from an edge (33) of the light source. 10. Light source according to one of the preceding claims, characterized in that the plurality of rods (8) extends projecting from the same substrate (10). 11. Light source according to the preceding claim, characterized in that an integrated electronic circuit (34) is arranged on the substrate (10), on the face opposite to the face from which the rods (8) extend. , said integrated circuit being configured for 15 pilot the selective activation of the zones (4, 6) of rods, and of the pixels (40, 60) which can compose each of these zones. 12. Light module for a motor vehicle comprising a light source (l) according to one of the preceding claims and an optical system (6) for projecting (2) the light generated by the light source. 13- Lighting and / or signaling device comprising a housing (2) for receiving at least one light module (l) according to the preceding claim. 14. Device according to the preceding claim, characterized in that it comprises a system for detecting external conditions and / or the projected image for controlling in real time the emission modes of the zones (4, 6) of rods ( 8). 2 5 15. Device according to any one of claims 13 or 14, characterized in that the two zones (4, 6) of rods (8) define an illuminating surface of the light source (l) whose peripheral edge defines a contour of the light beam projected by the device.