Light emitting device for object detection

Abstract

One aspect of the invention relates to a light-emitting device (100) for a motor vehicle, comprising:-a plurality of light-emitting modules (110) emitting pulsed visible light modulated by means of a high-frequency light-emitting code, each light-emitting module (110) comprising at least two sectors (151, 152, 153), each sector grouping a plurality of light-emitting diodes (130) around a driver circuit (120); and-means for receiving light emitted by each of the light emitting modules (110) after reflection from the object (20), where the light emitting modules (110) comprise a delay locked loop (140) connected to the driver circuits (120) of each of the sectors (151, 152, 153) to ensure synchronization of the driver circuits. A further aspect of the invention relates to a driving assistance system of a motor vehicle, comprising at least one such lighting device (100).

Description

Technical Field

[0001] The present invention relates to a lighting device for a motor vehicle suitable for object detection and a driver assistance system for a motor vehicle, the driver assistance system comprising the lighting device. Background Art

[0002] With the development of autonomous vehicles, driving assistance methods have greatly improved in recent years. One of the most useful assistance methods is the assistance method for detecting pedestrians or objects in the vehicle environment.

[0003] Devices for detecting the presence of pedestrians or objects in a vehicle environment (referred to as object detection devices for short) are known. These devices generally use so-called LiDAR (Light Detection and Ranging) technology, which is based on analyzing the characteristics of a light beam (usually a laser beam) emitted by a specific light source and reflected by an object. With LiDAR technology, the distance between the light source and the object is measured based on the time difference between the emission of the laser pulse and the reception of the reflected pulse. Object detection devices using LiDAR are relatively simple to implement, because the light source emits a single high-power infrared signal, which is reflected from the object; when the infrared signal is received by the sensor, the flight time of the signal is measured. However, such object detection devices require specific equipment for emitting the infrared signal and receiving the reflected signal.

[0004] To ensure that detection rates and / or false alarm rates meet standards, supplementary technologies are required. For this purpose, three auxiliary devices based on different technologies are often combined; the data generated by these different auxiliary devices is cross-checked and a final data set is generated to notify the driver, or in the case of autonomous vehicles, the vehicle itself, of the presence of pedestrians or objects in the vehicle's environment. However, adding three different devices to the same area of the vehicle can burden this area, which already has high demands due to its congestion.

[0005] To address the congestion problem, the idea has been to use existing lighting on vehicles (such as the vehicle's daytime running lights) to perform object detection. However, the light source of modern lighting fixtures is typically a group of light-emitting diodes controlled by a driver circuit. The light-emitting diodes (LEDs) in current vehicle lighting fixtures emit visible light continuously, making it difficult to detect after reflection from objects, especially when combined with natural sunlight, light from streetlights, and other outdoor light sources. To facilitate detection of the light emitted by the LEDs and reflected by objects, the idea has been to modulate the light; the light beam emitted by the LED is then pulsed and modulated with a high-frequency code. However, to be effective and therefore detectable, the light beam modulation must be precise; therefore, the LEDs forming the light source must all emit light simultaneously to avoid interference. Currently, the current trend is to arrange LEDs in rows, layers, or grids to achieve stylistic effects, which means that some LEDs are far away from the driver circuits that control them. LEDs closer to or farther away from the driver circuits result in a time lag in the light emitted by some LEDs compared to others. This lag causes the emission of the signal to spread out over time, which has two consequences. First, this transmission delay carries over to the signal reflected from the object and retransmitted to the vehicle's sensors. This makes it more difficult to determine the time lag between the emission of a light pulse and the reception of the reflected pulse. Second, the spread of the pulses reduces the signal-to-noise ratio. In fact, all else being equal, it's easier to detect the intensity of simultaneous pulses at a sensor than the intensity of multiple emissions spread out over time. Summary of the Invention

[0006] To address the above-mentioned problems of interference and time lags in LED emissions, the applicant has proposed a lighting device suitable for object detection in which LEDs are grouped together in sectors around driver circuits that power the LEDs, the driver circuits being synchronized by delay locked loops.

[0007] According to a first aspect, the present invention relates to a lighting device for a motor vehicle, the lighting device comprising:

[0008] - at least one first lighting module configured to emit pulsed visible light modulated to transmit a high-frequency lighting code, the at least one first lighting module comprising at least two sectors, each sector grouping a plurality of light-emitting diodes, the plurality of light-emitting diodes being supplied with power by a driver circuit configured to modulate power received by the light-emitting diodes according to the high-frequency code so as to emit the emitted pulsed visible light, and

[0009] - a receiving device for receiving the light emitted by the at least one first light emitting module, for receiving the light emitting code after the pulsed light emitted by the at least one light emitting module is reflected from an object,

[0010] Therein, the at least one first lighting module comprises a delay locked loop connected to a driver circuit of each of the sectors of the corresponding lighting module in order to synchronize the modulation performed by said driver circuit according to a code.

[0011] The lighting device is a light emitting element configured to be installed in a vehicle, and preferably includes a housing configured to be installed in a vehicle, the lighting module being installed in the housing. Preferably, a plurality of lighting modules are installed in the housing.

[0012] The lighting module is preferably a set of components that are integral with one another. Preferably, the lighting module can be mounted in a housing of a lighting device. Preferably, the lighting module is configured to perform or contribute to a supervisory lighting function or a signaling function. When a lighting module contributes to a signaling function or a lighting function, it should be understood that at least one other lighting module, for example, included in another lighting device, contributes to that function.

[0013] A light-emitting diode (LED) is understood to mean a light source that emits incoherent light and, as is known, is very suitable for use as a light source for signaling or lighting in motor vehicles, in contrast to laser sources (including laser diode sources). Laser sources, which emit temporally and spatially coherent light, have the disadvantage of being a risk to eye safety, which means they must be controlled using complex and expensive means.

[0014] It will be appreciated that the driver circuit is connected to the LEDs of its sector to supply them with power, while modulating the power received by the LEDs at a high frequency according to a code, such that the light emitted by the LEDs is modulated according to the code. Preferably, the driver circuit operates as a high-frequency switch capable of alternately blocking or conducting the power supply intended to supply power to the LEDs of the driver circuit's sector. Alternatively, the driver circuit is provided with passive or preferably active components capable of adapting the power supplied to the LEDs of the driver circuit's sector based on the received code, in order to ensure that the code is correctly transmitted in the form of pulsed light.

[0015] The lighting device according to the present invention implements or at least contributes to lighting and / or signaling functions known to those skilled in the art. Lighting functions include, for example, high beam, front fog light and low beam functions. Signaling functions include, for example, position light (PL), turn indicator and daytime running light (DRL) functions. The daytime running light and position light are particularly advantageous for implementing the present invention because these functions can be implemented by the same light emitting diodes; therefore, the same light emitting diodes can contribute to night-time and daytime detection functions, while performing regulatory signaling functions. Therefore, this provides a lighting device that can contribute to the detection function, making it possible to avoid the costs associated with a lighting device dedicated to the detection function, while performing a regulatory function.

[0016] Furthermore, the lighting device according to the present invention is particularly well-suited for implementing complex DRL / PL functionality, where multiple sectors, each comprising multiple LEDs, are used to uniquely brand a vehicle. In such lighting devices, it is common to find numerous LEDs distributed within the same module, such as in rows, layers, or grids, for example, at least 12 LEDs, preferably 30 LEDs. In the device according to the present invention, these LEDs are distributed across multiple sectors, with each sector powered by a driver circuit that supplies power to the LEDs in the corresponding sector.

[0017] In practice, a device suitable for implementing the DRL / PL function allows the detection function to be implemented using a majority of the LEDs required for the signaling function. "Majority" is understood to mean that more than 50% of the LEDs assigned to that function transmit a code, preferably more than 75%, and preferably all of the LEDs transmit a code. This is particularly relevant when the LEDs are similar in terms of flux emission characteristics and activation current. Since a majority of the LEDs contribute to the signaling function of illuminating an object in front of the motor vehicle, the detection of pulsed light from the LEDs is not interfered with by the detection of non-pulsed light emitted by the same function. This improves the signal-to-noise ratio of the sensor's reception of the illuminated code.

[0018] Alternatively, if the lighting function is implemented by different LEDs, it is advantageous if the LED representing more than 50% of the lighting flux attributable to this function transmits a code, preferably more than 75% of this flux, preferably all of this flux.

[0019] Similarly, it is advantageous to implement lighting functions, such as low beam and high beam, using LEDs whose power supply is modulated at a high frequency to transmit a code. Multiple LEDs are often used to generate low beam and high beam, sometimes within the same lighting module (e.g., a dual-function lighting module). It is then preferred to use at least one driver circuit capable of modulating the power supply to a sector of LEDs grouped together for the low beam function at a high frequency according to the code, and to use a driver circuit capable of modulating the power supply to a second sector of LEDs grouped together for the high beam function at a high frequency according to the same code, in synchronization with the power supply to the sector of LEDs. In another example, the high beam function and / or the low beam function include LEDs that can be individually activated and deactivated, for example, to emit a partial high beam (where some lighting zones are activated or deactivated), or alternatively or additionally, to emit a low beam, where some LEDs corresponding to a cutoff line are activated or deactivated so that the center of the cutoff line is shifted horizontally relative to the vehicle when the lighting device is installed on the vehicle, thereby implementing a directional low beam function known as DBL (Dynamic Bending Light). Since most LEDs emit pulsed light modulated according to the code, the detection of pulsed light from the LED is not interfered with by the detection of non-pulsed light emitted by the same function. This improves the signal-to-noise ratio of the sensor receiving the illuminated code.

[0020] With sectorized LEDs and delay locked loops connected between the driver circuits of the individual sectors, the lighting modules of this lighting device can synchronously emit all the light rays forming the light beam of the lighting device without any risk of interference. The lighting device according to the invention is therefore suitable for object detection.

[0021] In addition to the features just mentioned in the previous paragraph, the lighting device according to one aspect of the present invention may have one or more of the following additional features, which may be employed individually or in any technically feasible combination:

[0022] A delay locked loop is connected to the internal clock of each of the driver circuits to adjust the advanced clock of the driver circuit to the delayed clock of the driver circuit.

[0023] In each sector, the light-emitting diodes are connected to a driver circuit via conductor tracks, all conductor tracks of the same sector having the same track length, so that all light-emitting diodes of the same sector are controlled synchronously by the driver circuit.

[0024] - In each sector, the length of the conductor track is equal to the distance between the driver circuit and the light-emitting diode farthest from said driver circuit, the conductor track of the light-emitting diode farthest from the driver circuit forming a delay line.

[0025] The receiving device comprises at least one light sensor and a blue light optical filter.

[0026] The receiving device is connected to a calculation unit which determines the time of flight of the waves of the modulated pulsed light and measures the distance between the object and the light-emitting device.

[0027] For each sector of the at least one first lighting module, the light-emitting diodes of these sectors are grouped together on a same substrate, in particular an FR4 or IMS substrate.

[0028] - for each lighting module, the light emitting diodes of the same lighting module are grouped together on the same substrate, in particular an FR4 or IMS substrate,

[0029] - In addition to the at least one first light emitting module, the device comprises at least one second light emitting module connected to the delay locked loop of the at least one first light emitting module.

[0030] Adjusting the advanced clock of the driver circuit to the delayed clock of the driver circuit should be understood to mean that the clocks of the two circuits are brought to the same clock value so that the modulation of the code by the two driver circuits is simultaneous, within a residual error.

[0031] A second aspect of the present invention relates to a driver assistance system for a motor vehicle, characterized in that the driver assistance system includes at least one first light-emitting device according to the first aspect and one second light-emitting device according to the first aspect, the first light-emitting device and the second light-emitting device being combined with each other for detecting the same object.

[0032] A third aspect of the present invention relates to a driving assistance system for a motor vehicle, characterized in that the driving assistance system includes at least one first device for detecting objects in the environment of the motor vehicle, and the light-emitting device according to the first aspect constitutes a second object detection device, which provides redundancy for the first object detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other advantages and features of the present invention will become clear from a reading of the following description illustrated by the accompanying drawings, in which:

[0034] Figure 1 An example of a vehicle equipped with a lighting device according to the present invention is schematically shown;

[0035] Figure 2 Schematically shows an example of a modulated light pulse emitted by a light emitting device according to the present invention;

[0036] Figure 3schematically illustrates an example of a control signal transmitted by a driver circuit connected to a delay locked loop according to the present invention; and

[0037] Figure 4 An example of a lighting module is schematically shown, comprising a driver circuit connected to a delay locked loop according to the invention.

[0038] In the drawings, the same reference numerals have been used to identify the same elements. For the sake of readability of the drawings, the elements in the drawings are not shown to scale. DETAILED DESCRIPTION

[0039] An exemplary embodiment of a light emitting device according to the present invention is described in detail below with reference to the accompanying drawings. This example illustrates the features and advantages of the present invention. However, it will be recalled that the present invention is not limited to this example.

[0040] Figure 1 FIGURE 1 shows an example of a motor vehicle 10 equipped with two lighting devices 100 according to the present invention. This example shows a pedestrian 20 crossing in front of vehicle 10. Vehicle 10 is equipped with two lighting devices 100, such as daytime running lights, which illuminate a road scene SR in front of the vehicle. Lighting devices 100 are integrated into a driver assistance system that can detect pedestrian 20.

[0041] The lighting device 100 according to the present invention can be any basic lighting device present on a vehicle. For example, the lighting device 100 can be a daytime running light, a position light, a signal light, a side light strip, a headlight grille, or any other external lighting device typically integrated into a vehicle to allow visibility on the road. The lighting device can then be used to detect pedestrians or objects on the road scene or in the vehicle's external environment. The lighting device can also be a lighting device inside the vehicle; the lighting device can then be used to detect objects or people inside the vehicle.

[0042] The light emitting device 100 is used to emit pulsed light modulated by a high-frequency light code. The light code is a binary cyclic code consisting of a series of 1s and 0s, where 1 corresponds to a pulse and 0 corresponds to no light emission. The light beam emitted by the LED included in the light emitting device is modulated to transmit the light code. Therefore, the LED emits a series of light pulses at a rate of approximately 10ns to 20ns, which corresponds to high-frequency modulation of the power supply to the LED at 10MHz to 400MHz, preferably 30MHz to 200MHz, and preferably 50MHz to 100MHz. Figure 2 An example of the code is shown in Part A of Figure 2An example of a light pulse corresponding to this code is shown in Part B of Figure 1. It should be noted that by emitting a light beam modulated at a high frequency by the code, the human eye cannot perceive this modulation. To the human eye, the light beam appears continuous; the illuminated code is invisible. Therefore, emitting a light code via modulated light beams can be used for object detection.

[0043] like Figure 4 As schematically shown in FIG, the lighting device 100 according to the present invention comprises a plurality of lighting modules 110, each of which comprises at least two driver circuits 120 and a plurality of white LEDs 130, organized into sectors 151, 152, 153. A driver circuit 120 (also referred to as a driver) is a device for supplying a DC current to the connected LEDs. Thus, the driver circuit 120 controls the plurality of LEDs 130. According to the present invention, the lighting module 110 comprises a plurality of sectors 151, 152, 153, each of which comprises a driver circuit 120, to which the plurality of LEDs 130 are connected. Figure 4 In the example shown, a lighting module 110 includes three sectors 151, 152, and 153, each of which includes a driver circuit 120 and three LEDs 130. Sectors 151, 152, and 153 are geographical areas of the lighting module in which the driver circuit 120 is connected to the LEDs 130, all of which are positioned within the environment of the driver circuit 120, at a relatively short distance from the driver circuit. Organizing the driver circuit and LEDs of the lighting module 110 into sectors makes it possible to position the driver circuit at a relatively small distance from each LED. Consequently, the LEDs 130 of the lighting module are not far from the driver circuit that controls them; all LEDs 130 of the same sector 151, 152, and 153 are approximately the same distance from the driver circuit 120 that controls them, thereby limiting or even avoiding the risk of time lags when some of the LEDs emit light.

[0044] exist Figure 4 In the example of FIG, the lighting module 110 includes three driver circuits and nine LEDs organized into three sectors. Of course, the number of sectors per lighting module, the number of driver circuits per sector, and the number of LEDs are given only as examples and may vary depending, in particular, on the type of lighting device, the desired lighting effect, the arrangement of the LEDs, etc.

[0045] Regardless of the number of sectors 151, 152, 153 and / or driver circuits 120, the lighting module according to the present invention includes a delay-locked loop (DLL) 140. The delay-locked loop 140 is a digital circuit for changing the phase of a clock signal. The DLL compensates for propagation delays so that only a small lag exists between the output clock signals.

[0046] In a lighting module according to the present invention, a DLL 140 is connected to each of the module's driver circuits 120 to synchronize commands across all of the module's driver circuits 120. In practice, DLL 140 connects to the internal clocks of each driver circuit 120 in a lighting module 110 and monitors these internal clocks to determine whether some of these internal clocks lag behind or lead behind other internal clocks. If DLL 140 detects that an internal clock is lagging or leading, it intervenes in the internal clock or clocks of one or more driver circuits 120 that are ahead, aligning these advanced internal clocks to the internal clock of the driver circuit that lags the furthest. In other words, DLL 140 delays the advanced internal clocks of the driver circuit 120 so that all driver circuits 120 are aligned to the internal clock of the driver circuit 120 that lags the furthest.

[0047] exist Figure 3 In the example of FIG, DLL 140 monitors the internal clock of the first driver circuit (clock signal line S1) and the internal clock of the second driver circuit (clock signal line S2) shown as a function of time t. This monitoring indicates that clock signal S1 leads clock signal S2: for example, pulse i11 of signal S1 is transmitted before pulse i21 of signal S2. DLL 140 then modifies the transmission phase of clock signal S1 so that the pulses of signal S1 are synchronized with the pulses of signal S2. Figure 3 In the example of , after the clock signals S1 and S2 are adjusted, the pulse i14 of the signal S1 and the pulse i23 of the signal DS2 are emitted simultaneously: the clock signals S1 and S2 are then synchronized.

[0048] The DLL 140 monitors all the driver circuits 120 of the lighting module 110 in the same manner as explained above and adjusts the clocks of all of the driver circuits to synchronize them. Therefore, all the driver circuits 120 of the lighting module 110 simultaneously control the LEDs 130 to which they are connected. Since the LEDs 130 are all close to the driver circuits, they emit various lights at the same time.

[0049] However, if the organization into sectors requires that certain LEDs 130 be at a significantly different distance from the driver circuit 120 than other LEDs of the same sector (e.g., sector 151), the time lag that could be caused by such distance differences can be prevented by connecting all LEDs 130 of sector 151 to the driver circuit 120 of this sector 151 by means of conductor tracks of the same length. In practice, as is known in the field of lighting devices for motor vehicles, the LEDs 130 and the driver circuit 120 are mounted on a PCB (printed circuit board) or IMS (insulated metal substrate) type substrate, wherein each LED 130 is connected to the driver circuit 120 by a conductor track. The conductor tracks connecting each LED 130 of a sector to the driver circuit 120 of this sector have equal lengths.

[0050] For example, in Figure 4 In an embodiment of the present invention, if the three LEDs 130 of a sector 151 are positioned at unequal physical distances relative to the driver circuit 120 of said sector 151, they can all be connected to the driver circuit 120 by conductor tracks (not shown) of equal length. All conductor tracks connecting the LEDs of the same sector to the driver circuit of the sector can have the same length. The length of these conductor tracks is determined according to the LED farthest from the driver circuit. Therefore, the length of all conductor tracks is equal to the length of the conductor track used to connect the driver circuit 120 to the LED farthest from said driver circuit. The conductor track connecting the farthest LED 130 to the driver circuit 120 is a conventional conductor track; the conductor track connecting the driver circuit 120 to the LED closest to the driver circuit 120 forms a delay line. All LEDs 130 of the same sector 151, 152, 153 of the light-emitting module can therefore be connected equidistantly to the driver circuit that controls them.

[0051] The distance between the driver circuit and the LED is the physical distance, defined as the "point-to-point" distance between the driver circuit's control output and the LED's input terminal. Therefore, the concept of "furthest (farthest away)" should be understood in terms of physical distance: the LED farthest from the driver circuit is the LED with the greatest distance from the driver circuit compared to the distances of the other LEDs. Similarly, the concept of "closest" should be understood in terms of physical distance: the LED closest to the driver circuit is the LED with the shortest distance from the driver circuit compared to the distances of the other LEDs.

[0052] Thus, the physical distance between the driver circuit 120 and the LEDs 130 it controls can vary, while the connection distance between the driver circuit 120 and the LEDs 130 is constant.

[0053] In other words, because all conductor tracks have the same length, the conductor tracks closest to the LEDs in the driver circuit include loops and / or detours that enable the creation of delay lines. Consequently, when the driver circuit 120 issues a light emission command, the control signal sent by the driver circuit 120 is simultaneously received by all LEDs 130 connected to that driver circuit. The LEDs 130 in the same sector 151, 152, 153 thus emit their light simultaneously and in a synchronized manner. In parallel, the driver circuits 120 in each sector 151, 152, 153 are also synchronized via the DLL 140. Thus, there is a first level of synchronization at the level of each sector 151, 152, 153, and a second level of synchronization at the level of the lighting module. Consequently, the light beams emitted by all LEDs 130 in the lighting module 110 are necessarily synchronized, thereby enabling efficient light beam modulation, where all LEDs in the module emit the same bit of the lighting code simultaneously.

[0054] As just described, the lighting module 110 enables synchronous emission of modulated light beams. To enable object detection, the lighting module is associated with a receiving device for receiving the light beam reflected by an object (not visible in the figure). This receiving device is integrated into the lighting device 100 of the present invention. This allows the light beam to be received after it has been reflected by the object to be detected. The receiving device comprises a light sensor or a group of light sensors; these one or more sensors may be, for example, photon counters, preferably avalanche diodes. The photon counters are preferably distributed on a common high-density substrate, preferably to form a detection matrix. The sensors are preferably associated with a blue light optical filter—i.e., a bandpass filter designed to capture only light with blue wavelengths and suppress all other wavelengths. In practice, a white light LED suitable for signaling comprises a light-emitting chip that emits blue light and to which a phosphor is applied that converts a portion of the blue light into yellow light. The mixture of the unconverted blue light emitted by the chip and the yellow light converted by the phosphor produces white light. Similarly, an amber light LED suitable for signaling comprises a chip that emits blue light and to which a suitable phosphor is applied. The blue light optical filter allows the separation of the blue light emitted by the light module 110 and reflected by the object 20, which corresponds to the majority of the light beam, in particular the emission line of the light-emitting chip, from the remaining spectrum of light coming from the sun or from any other external light source emitting light in the visible range in the vehicle environment. This significantly improves the signal-to-noise ratio of the detection.

[0055] The receiving device is connected to a computing unit installed in the lighting device or housed in any other location in the vehicle, preferably directly on the sensor, which determines the time of flight of the light beam and derives from this a measurement of the distance between the vehicle and the detected object. The time of flight is the propagation time of the wave of the light beam emitted by the lighting module 110 in the environment, that is, the time required for the light beam to propagate to the object and return to the receiving device. The distance between the object and the vehicle is determined based on this time of flight. It will be appreciated that the synchronous emission of the light beams by the lighting module 110 makes it possible to improve the determination of the time of flight. It will also be appreciated that the "object detection" function can be implemented by the lighting device 100 in parallel with its standard lighting function.

[0056] The lighting device 100 as has just been described can be used alone for object detection, in particular if the lighting device is a lighting device for the interior of a vehicle.

[0057] The lighting device 100 can also be used in combination with another similar lighting device. Two lighting devices 100 (for example, two front lighting devices of a vehicle) can be combined with each other to detect the same object.

[0058] The lighting device 100 can also be integrated into a driver assistance system for a motor vehicle. In practice, a driver assistance system often requires a combination of two or even three different object detection devices, i.e., they operate using different technologies. These object detection devices should be complementary. The lighting device according to the invention can constitute one of these object detection devices. It has the advantage of using a specific technology that has not yet been used, since it performs object detection by means of a light beam in the visible light range. It has the additional advantage of not adding mass and congestion, since it uses lighting devices already present on the vehicle. It also has the advantage of being able to be implemented on multiple lighting devices of the same vehicle (for the purpose of detecting objects in the same area or in different areas of the vehicle) without the risk of interference, simply by selecting a different lighting code for each lighting device used.

[0059] Although described by way of a number of examples, variations, and embodiments, the lighting device according to the present invention includes various variations, modifications, and improvements that will be apparent to those skilled in the art, and it should be understood that these variations, modifications, and improvements form part of the scope of the present invention. For example, upon reading this application, a person skilled in the art will understand that its principles can be readily applied to other lighting devices on the exterior of a motor vehicle, such as rear signal lamps on a motor vehicle.

Claims

1. A lighting device (100) for a motor vehicle, the lighting device comprising: - at least one light emitting module (110), the at least one light emitting module being configured to emit pulsed visible light modulated to transmit a high-frequency light emitting code, the at least one first light emitting module (110) comprising at least two sectors (151, 152, 153), each sector grouping a plurality of light emitting diodes (130) and a driver circuit (120), each of the light emitting diodes being supplied with power by the driver circuit (120) of the corresponding sector so as to modulate the power received by the light emitting diode of the corresponding sector according to the high-frequency code so as to emit the pulsed visible light, and - a receiving device for receiving light emitted by the at least one first light emitting module (110), the receiving device for receiving pulsed light modulated according to the code after the pulsed light emitted by the at least one first light emitting module is reflected from an object (20) outside the vehicle, - wherein the modulation frequency is greater than 10 MHz, and The at least one first light emitting module (110) comprises a delay locked loop (140) connected to a driver circuit (120) of each of the sectors (151, 152, 153) of the corresponding light emitting module in order to synchronize the modulation performed by the driver circuit according to the code.

2. The lighting device according to the preceding claim, characterized in that The delay locked loop (140) is connected to the internal clock of each of the driver circuits (120) to adjust the advanced clock of the driver circuit to the delayed clock of the driver circuit.

3. A lighting device according to any one of the preceding claims, characterized in that In each sector (151, 152, 153), the light emitting diodes (130) are connected to the driver circuit via conductor tracks, and all conductor tracks of the same sector have the same track length, so that all light emitting diodes (130) of the same sector (151, 152, 153) are synchronously controlled by the driver circuit.

4. Lighting device according to the preceding claim, characterized in that In each sector (151, 152, 153), the length of the conductor track is equal to the distance between the driver circuit (120) and the light emitting diode farthest from the driver circuit, the conductor track of the light emitting diode farthest from the driver circuit forming a delay line.

5. A lighting device according to any one of the preceding claims, characterized in that For each sector of the at least one first lighting module, the light emitting diodes (130) of the sector are grouped together on a same substrate, in particular an FR4 or IMS substrate.

6. A lighting device according to any one of the preceding claims, characterized in that In addition to the at least one first light emitting module, the apparatus further comprises at least one second light emitting module connected to the delay locked loop of the at least one first light emitting module.

7. A lighting device according to any one of the preceding claims, characterized in that The receiving device includes at least one light sensor and a blue light optical filter.

8. A lighting device according to any one of the preceding claims, characterized in that The receiving device is connected to a calculation unit which determines the flight time of the wave of the modulated pulsed light and measures the distance between the object (20) and the light emitting device (100).

9. A driving assistance system for a motor vehicle, characterized in that The driver assistance system comprises at least one first device for detecting objects in the environment of the motor vehicle, in particular a radar, wherein the lighting device (100) as claimed in one of claims 1 to 6 constitutes a second object detection device, which provides redundancy for the first object detection device.

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