Detection and / or communication system of motor vehicle comprising module for receiving light beam

Abstract

The invention relates to a system (1) of a motor vehicle, comprising a receiving module (3) capable of receiving a light beam (F2), where the receiving module comprises a basic acquisition module (32) comprising a photodetector (32a) capable of converting its received light signal into an electrical signal, characterized in that the photodetector (32a) is configured to receive the light beam (F2) from the receiving module (3). The receiving module comprises an optical unit (31) arranged in front of the basic acquisition module, the optical unit comprising: a lens (52) made of an absorptive material to form a first optical bandpass filter (I1) capable of transmitting a first wavelength range (BP1); and an optical element (53) arranged to form a second optical interference filter (I2) transmissive to a second wavelength range (BP2) comprised at least partially within the first range and substantially narrower than the first range.

Description

[0001] The invention relates to the field of automotive lighting functions and data transmission functions using light emitted by an automotive lighting system. More precisely, the invention relates to a system of a motor vehicle for receiving data transmitted by a light beam.

[0002] In the automotive field, it is known to use the light beam emitted by a light module both to perform a given photometric function and to transmit data.

[0003] Conventionally, the light source used to emit this light beam is controlled by a pulse width modulated (PWM) electrical signal. Thus, this PWM signal periodically activates and deactivates the light source, so that the emitted light beam consists of continuous light pulses with a sufficiently high frequency that the human eye can no longer distinguish them. The intensity of the emitted light beam depends on the duty cycle of this PWM signal, making it possible to control the intensity by adjusting this duty cycle. This PWM signal can then be modulated with a data sequence so that this data sequence is carried by the light beam. This enables the light beam to maintain its original function, i.e. to perform a photometric function while carrying the data sequence. This type of technology is, for example, known as Visible Light Communication (VLC) or also Light Fidelity (LiFi).

[0004] Thus, in addition to performing one or more photometric functions (such as daytime running lights or low beam lighting), various functions can be implemented by means of a lighting module of this type. For example, a lighting module can thus be integrated into a transmitting module capable of performing a function involving the communication of a data sequence with another vehicle or with a piece of infrastructure equipped with a receiving module capable of demodulating the received light beam in order to extract the data sequence therefrom. In another example, a headlight comprising a transmitting module can be equipped with a receiving module in order to receive the emitted light beam (after being reflected on an object in the vicinity of the vehicle). The travel time of the emitted light beam can then be determined by demodulating and extracting the transmitted data sequence, and thus the distance between the vehicle and the object can be assessed.

[0005] However, this type of system based on the use of a transmitting module capable of performing both photometric optical functions and data transmission has disadvantages. The receiving module intended to receive the light beam carrying the data, whether it is arranged in the same vehicle or in another vehicle, must include at least one photodetector for converting this light beam into an electrical signal in order to demodulate this signal and extract the data sequence therefrom.

[0006] Under certain conditions, the signal-to-noise ratio of this photodetector may degrade significantly. This is particularly true in bright sunlight. In fact, under such conditions, the light from the sun in the visible spectrum in which the light source of the transmitting module operates may be significantly greater than the light from the received beam, saturating the photodetector. In this state, the photodetector enters a nonlinear operating state and cannot adequately convert the beam into an electrical signal that can be demodulated without losing information.

[0007] In order to avoid such saturation of the photodetector, the received light beam can be filtered to a very narrow wavelength band, for example between 420 nm and 470 nm, in order to limit the influence of sunlight. However, the width of the solar radiation spectrum makes it particularly complex to implement a bandpass filter capable of filtering the light beam over a narrow band. For example, it would be necessary to superimpose more than fifty thin layers to form an interference filter capable of adequately reflecting the entire solar radiation spectrum outside this narrow band. Moreover, in addition to the manufacturing complexity, the cost of obtaining a zero or sufficiently low gain of such a filter outside the narrow band and a steep slope of the gain at the limit of this narrow band becomes prohibitive.

[0008] Therefore, there is a need for a system capable of transmitting data sequences from a transmission module (which incorporates a lighting module participating in the performance of a photometric function) to an acquisition module, wherein the signal-to-noise ratio is optimal under all weather conditions (including bright sunlight) and wherein the implementation complexity and cost are reasonable.

[0009] The present invention falls within this background and is intended to meet this need.

[0010] For these purposes, the invention relates to a system for a motor vehicle, comprising a receiving module capable of receiving a light beam, the receiving module comprising a basic acquisition module comprising a photodetector capable of converting the optical signal it receives into an electrical signal, characterised in that the receiving module comprises an optical unit arranged in front of the basic acquisition module, the optical unit comprising: a lens made of an absorptive material to form a first optical bandpass filter capable of transmitting a first wavelength range; and an optical element arranged to form a second optical interference filter capable of transmitting a second wavelength range at least partially included in the first range and substantially narrower than the first range.

[0011] Therefore, the present invention proposes filtering the received light beam in two stages. The first filter roughly narrows the light beam by eliminating a large part of the spectrum of the light beam, but the passband of this filter is not particularly narrow. This type of filter can be easily manufactured using lenses made of absorbing materials, for example by body coloring. The second filter (which is an interference filter or a dichroic filter) then refines the received light beam by selecting a narrow band in the passband of the first filter. Assuming that most of the spectrum has been eliminated by the first filter, the number of layers in the second filter can be greatly reduced without affecting the performance of this second filter. Therefore, the manufacturing complexity and cost of this second filter can be reduced. In addition, in bright sunlight conditions, when sunlight is added to the light emitted by the transmitting module, these filters greatly reduce the impact of sunlight and thus prevent photodetector saturation.

[0012] It should be noted that the first filter may equally well be arranged upstream of the second filter, and vice versa, without departing from the scope of the invention. Other optical elements may also be added, forming other interference filters that further narrow the band of the received light beam. The second range may also be partially or completely within the first range.

[0013] Preferably, the optical unit has a focal plane which passes through the photodetector of the elementary acquisition module.

[0014] In the present invention, the absorptive material of the lens may be selected so that the first optical filter has a transmission coefficient of at least 80% in a first range or passband and a transmission coefficient of less than 80% outside the first range. The lens may be made of a single tinted or colored material, such as glass or thermoplastic material, to form the first filter; or the lens may be made of a plurality of materials, for example arranged in layers, at least one of which forms the first filter.

[0015] Advantageously, the absorptive material of the lens is selected so that the first range is centered on a wavelength of the visible spectrum, i.e. a wavelength between 380 nm and 780 nm. For example, the first optical filter may have a transmission peak, i.e. a peak with a transmission coefficient greater than 95%, in the violet or blue, in particular between 380 nm and 500 nm, in particular substantially at 390 nm or substantially at 450 nm. Where appropriate, the first range, i.e. the wavelength range for which the transmission coefficient of the first filter is greater than or equal to 80%, extends partially or completely in the visible spectrum and may, for example, be the range 420 nm to 490 nm, the transmission coefficient of the first filter being less than 80% outside this range and in particular less than 40% in green, yellow, red and infrared.

[0016] For example, the absorbent material of the lens may be a glass composition as described in patent EP 0481165.

[0017] In the present invention, the optical element can be arranged so that the second optical filter has a transmission coefficient of at least 80% in the second range or passband, and has a transmission coefficient of less than 80% in the first range outside the second range. The optical element can be arranged so that the second optical filter has a transmission coefficient that can be less than and / or greater than 80% outside the first range as well. Without departing from the scope of the present invention, the second optical filter can have other passbands outside the first range in particular. This second interference filter improves the signal-to-noise ratio of the system by reflecting what is not absorbed or should not be absorbed by the first filter.

[0018] Advantageously, the optical elements are arranged such that the width of the second range is less than 30 nm.For example, the second range may be centred on a wavelength within the first range, for example between 445 nm and 450 nm.

[0019] In the case where the light beam is emitted from a solid-state light source (such as a light emitting diode), the white light used to obtain the light beam is usually obtained from a blue light generator, and the photoluminescent material or phosphor absorbs part of this blue light to emit yellow light in response, and the rest of the blue light and this yellow light are synthesized by addition to form white light. However, this absorption-reemission means that yellow photons must be emitted more slowly than blue photons. Therefore, in the context of detecting obstacles by analyzing the travel time of the light beam, if only blue light is used instead of another wavelength range, or even the entire visible spectrum is used for evaluation, the evaluation resolution of the travel time will inevitably be higher. The fact that the second range is centered on a wavelength between 445nm and 450nm therefore reduces the uncertainty in detecting the distance from the obstacle to the vehicle. Symmetrically, this second range increases the data communication rate between the transmitting module and the receiving module.

[0020] In an example embodiment of the present invention, the optical element includes a stack of thin layers, each of which alternately has a high refractive index or a low refractive index. The low refractive index will be significantly lower than the high refractive index. This configuration is also known as a Bragg reflector. The thickness of each layer can be determined, for example, based on the center wavelength of the second range and the high refractive index and / or the low refractive index. It should be noted that the thickness of each layer will be significantly less than the center wavelength of the second range.

[0021] For example, one of the following materials can be used for the thin layer with a high refractive index: niobium pentoxide (Nb2O5), titanium dioxide (TiO2), tantalum pentoxide (Ta2O5), zirconium dioxide (ZrO2) or hafnium dioxide (HfO2). Silicon dioxide (SiO2) can be used, for example, for the thin layer with a low refractive index.

[0022] The number of layers in the optical element will advantageously be less than 20. In other words, the design of the optical element is simpler and less costly due to the presence of the first filter.

[0023] In one embodiment of the invention, the lens is a plano-convex lens and the optical element is a coating formed on a flat face of the lens. Where appropriate, said flat face of the lens may be the face of the lens oriented towards the elementary acquisition module.

[0024] In an alternative or cumulative embodiment, the optical element is a flat plate interposed between the lens and the elementary acquisition module.

[0025] Advantageously, the optical unit comprises a plurality of lenses including said lens forming the first optical filter and at least one further lens made of a transparent material.

[0026] In one embodiment of the present invention, the receiving module comprises a plurality of basic acquisition modules, each of which comprises a photodetector capable of converting the optical signal received by it into an electrical signal. Where appropriate, the optical unit may have a focal plane passing through each of the photodetectors.

[0027] For example, the group of photodetectors may form a sensor, such as a single electronic component.

[0028] Advantageously, the photodetector of the or each elementary acquisition module is an avalanche photodiode. This type of photodetector is also known as a single photon avalanche diode (SPAD). Thus, the group of avalanche photodiodes can form a silicon photomultiplier (SiPM). This type of photodetector can detect light with a high gain (e.g. 10 6 The invention can reduce the incidence of a single photon (a gain of the order of magnitude) and thus compensate for the degradation of the signal-to-noise ratio due to external conditions or due to absorption by the filter.

[0029] Advantageously, the receiving module comprises a demodulation unit connected to the or each photodetector and arranged to extract the data sequence from the electrical signal converted by this photodetector.

[0030] In one embodiment of the present invention, the system includes a transmitting module, which includes: a light emitting module capable of emitting a light beam, the spectrum of which has at least a portion in a second wavelength range; and a modulation unit, which is capable of receiving a data sequence and is arranged to use the received data sequence to modulate the emitted light beam.

[0031] For example, the light emitting module may be arranged such that the spectrum of the emitted light beam has a first peak in the visible spectrum, for example in the range of 440 nm to 500 nm, in particular at 450 nm.

[0032] In one embodiment of the present invention, the light emitting module comprises: a light source capable of emitting light, at least one or at least some of the wavelengths of which are in the second wavelength range; and an optical unit arranged to project the light emitted by the light source to form the light beam. The light source may be a laser source, a light emitting diode, a vertical cavity surface emitting laser (VCSEL) or a superluminescent diode (SLED). Where appropriate, the modulation unit may be arranged to control the light source, and in particular the electrical power supply to this light source, so as to modulate the light beam.

[0033] Advantageously, the modulation unit is arranged to generate a pulse width modulated control signal, modulate the control signal using the received data sequence, and control the emission of the light beam by the light module using the modulated control signal. For example, the modulation unit may be arranged to convert the received data sequence into a modulation signal and modulate the control signal using this modulation signal, for example in terms of amplitude, frequency or phase.

[0034] Advantageously, the system comprises a calculation unit arranged to detect the presence of a data sequence modulating the light beam emitted by the transmitting module in a data sequence extracted by the demodulation unit from an electrical signal converted by the photodetector from the light beam received by the receiving module, and to determine the travel time between the emission of the emitted light beam and the reception of the received light beam.

[0035] Advantageously, the emission module is arranged so that the light beam fully or partially participates in the performance of a predetermined legally prescribed photometric function. For example, it may be a daytime running light (DRL) which has the advantage of emitting at low intensity over a wide field.

[0036] Advantageously, the receiving module (and where applicable the transmitting module) is arranged in a headlight of the motor vehicle.

[0037] The invention also relates to a receiving module for a system of a motor vehicle according to the invention.

[0038] The invention also relates to a motor vehicle headlight comprising a receiving module according to the invention and, optionally, a transmitting module.

[0039] The present invention will now be described using examples, which are for illustration purposes only and in no way limit the scope of the invention, and with reference to the accompanying drawings, in which the various figures show:

[0040] [ Figure 1] is a schematic partial view of a system of a motor vehicle according to an example embodiment of the present invention;

[0041] [ Figure 2 ] schematically and partially shows [ Figure 1 ] an example embodiment of a receiving module of the system; and

[0042] [ Figure 3 ] schematically and partially shows [ Figure 2 ]The transmission spectrum of the optical unit of the receiving module in .

[0043] Throughout the following description, elements that are identical in structure or function and appear in the various figures are labeled with the same reference numerals unless otherwise specified.

[0044] [ Figure 1 ] shows a system 1 for a motor vehicle according to an example embodiment of the invention.

[0045] The system 1 comprises a transmitting module 2 arranged to transmit a light beam F1 and a receiving module 3 intended for receiving a light beam F2.

[0046] In the example described, the transmitting module 2 and the receiving module 3 are arranged in the same headlamp of a motor vehicle. The modules 2 and 3 may be arranged at different locations in the motor vehicle without departing from the scope of the invention.

[0047] The transmitting module 2 includes a light emitting module 21 and a modulation unit 22 .

[0048] The light module 2 is arranged so that the light beam F1 emitted by it has an electromagnetic spectrum S, at least a part of which is in the visible spectrum. Figure 1 ], the spectrum S has a first intensity peak P1 or line in the blue, for example at 450 nm. It should be noted that the spectrum S may have other intensity peaks, in particular an intensity peak in the infrared.

[0049] In order to emit this light beam F1, the light emitting module 21 comprises a light source 23 capable of emitting light and an optical unit 24 arranged to project these light rays to form the light beam F1. In the present invention, the optical unit 24 may equally well comprise one or more reflectors, one or more lenses, one or more apertures, or one or more collimators, or even a combination of several of these optical elements.

[0050] The light source 23 comprises, for example, a solid-state generator (not shown) capable of emitting blue light having an emission peak at 450 nm by electroluminescence and in response to a current passing through the generator, such as gallium nitride or GaN. The light source also comprises a photoluminescent element in the form of a resin comprising cerium-doped yttrium aluminum garnet (CE:YAG), capable of absorbing blue light, and emitting yellow light having a peak at 550 nm by photoluminescence and in response to excitation by this light.

[0051] The photoluminescent element is arranged on the generator in such a way that part of the blue light excites this element so that it emits yellow light by photoluminescence. Another part of the blue light passes through this element. Therefore, when the light source 23 is powered, it emits blue and yellow light at the same time, and the light thus formed appears white to the human eye.

[0052] In the case where the light beam F1 is partially or completely composed of white light, this light beam F1 can be used to partially or completely participate in the performance of a predetermined photometric function, in particular a function required by legislation. In this case, the optical unit 24 is arranged to shape this light beam F1 so that its photometric distribution meets the requirements of the function. For example, the light beam F1 can participate in the performance of a daytime running light (DRL) function.

[0053] In addition to this photometric function, the light beam F1 enables the system 1 to perform functions of detecting and evaluating the position of obstacles on the road and / or communicating with another vehicle or with a piece of road infrastructure.

[0054] The modulation unit 22 is capable of receiving a data sequence, for example a predetermined sequence in the case where it is used for detecting and evaluating the position of obstacles, in which case the sequence is stored in a memory of the system 1 (not shown) or, as a variant, is generated by a computer of the system 1 (not shown) for communication with a data sequence provided in another vehicle or in a piece of road infrastructure. Figure 1 ] to communicate with the systems that are exactly the same as the systems in the .

[0055] The modulation unit 22 is arranged to use this data sequence to modulate the light beam F1 emitted by the light emitting module 21 , for example by controlling the electrical power supply to the light source 23 .

[0056] For these purposes, the modulation unit 22 comprises a generator of a pulse width modulated control signal. This control signal is used to control a switch mode power supply (not shown) to the light source 23. Conventionally, the duty cycle of this control signal set by the modulation unit 22 is therefore used to control the average electrical power supplied to the light source 23, and therefore to control the luminous intensity of the light beam F1, so as to meet the requirements of the photometric function it performs.

[0057] In the example described, the modulation unit 22 is arranged to convert the data sequence into a modulation signal and to modulate the initial control signal using this modulation signal. It should be noted that several types of modulation may be equally well employed in the context of the present invention, and in particular on-off keying (OOK) modulation, pulse code modulation (PCM), pulse amplitude modulation (PAM), pulse width modulation (PWM), or pulse position modulation (PPM).

[0058] The emitted light beam F1 is therefore composed of a series of continuous light pulses with a sufficiently high frequency (e.g. greater than 30 MHz, in particular between 70 MHz and 100 MHz) so that the human eye can no longer distinguish them. In addition, the amplitude, width and / or position of each pulse relative to the period allow the light beam F1 to carry the data sequence to the receiving module 3.

[0059] The receiving module 3 comprises an optical unit 31 , downstream of which a plurality of basic acquisition modules 32 are arranged. The receiving module 3 further comprises a demodulation unit 33 .

[0060] Each of the elementary acquisition modules 32 comprises a photodetector 32a. Therefore, the light beam F2 received by the receiving module 3 is concentrated by the optical unit 31 on one or more of the photodetectors 32a.

[0061] Light beam F2 may equally well be light beam F1 emitted by transmitting module 2 and reflected by an obstacle or object located in the vehicle environment towards receiving module 3, or a light beam emitted by a transmitting module of a system of another vehicle or of a piece of road infrastructure equipped with a transmitting module similar to module 2.

[0062] The photodetectors 32a are identical and are each formed by an avalanche photodiode of a silicon photomultiplier. These photodiodes are distributed in an array. It should be noted that the dimensions of the photodetectors 32a are in the micrometer range. Thus, due to the use of avalanche photodiodes, the assembly forms a sensor with a receiving spatial resolution of the order of 0.1° and has particularly good detection capabilities even under degraded acquisition conditions.

[0063] Each of the photodetectors converts the portion of the light beam F2 that it receives into an electrical signal that it transmits to a demodulation unit 33 which can then extract the data sequence therefrom.

[0064] In the case where the system 1 implements a communication function, this data sequence can then be transmitted to the vehicle's computer in order to be interpreted, decoded and / or transmitted to equipment or a user of the vehicle.

[0065] In the case where the system 1 implements a function of detecting and evaluating the position of an object or an obstacle, this data sequence can be transmitted to the calculation unit 4 of the system 1. Thus, this calculation unit 4 can detect therein the presence of the predetermined data sequence with which the modulation unit 22 has modulated the light beam F1 emitted by the light module 21. In this case, the calculation unit can determine the travel time between the emission of the light beam F1 and the reception of the light beam F2.

[0066] Reference below Figure 2 ]and[ Figure 3 ] describes an embodiment of the optical unit 31.

[0067] like[ Figure 2 ] As shown in FIG. 1 , the optical unit 31 includes a plurality of lenses, including three lenses 51 made of a transparent or translucent material and a lens 52 made of an absorptive material, to form a first optical bandpass filter I1 capable of transmitting a first wavelength range BP1.

[0068] It should be noted that the number of lenses, the profile of the lenses and the Figure 2 ] constitute a non-limiting example of the invention, and this number, these profiles and these positions can be changed without departing from the scope of the invention.

[0069] In the example described, this set of lenses 51 and 52 has a focal plane that passes through the photodetector 32 a of the elementary acquisition module 32 .

[0070] The absorptive material of the lens 52 is a tinted glass selected so that the first optical filter I1 has a transmission coefficient of at least 80% in a first wavelength range BP1 and a transmission coefficient of less than 80% outside this first range BP1.

[0071] [ Figure 3 ] shows the transmission spectrum (shown as a dotted line) of this first optical filter I1 formed by the lens 52. It can thus be seen that the passband BP1 of the first filter I1 for which the transmission coefficient is greater than or equal to 80% is in the range from 420nm to 490nm, with a transmission peak at 450nm. Outside this range, the transmission coefficient is less than 80%, or even less than 50%.

[0072] The optical unit 31 further comprises an optical element 53 arranged to form a second optical filter I2 capable of transmitting a second wavelength range BP2 at least partially comprised in the first range BP1 and substantially narrower than the first range BP1.

[0073] In the example shown, the optical element 53 is an interference filter comprising a stack of thin layers each of which has a high or low refractive index alternately. The high refractive index layers are made of titanium dioxide (TiO2) and the low refractive index thin layers are made of silicon dioxide (SiO2).

[0074] The lens 52 is a plano-convex lens, and the optical element 53 is a coating formed on the flat surface of this lens oriented toward the photodetector 32 a .

[0075] The number of layers and the thickness of the layers have been determined such that the second optical filter I2 has a transmission coefficient of at least 80% in the second range BP2.

[0076] [ Figure 3 ] also shows the transmission spectrum of this second optical filter I2 formed by the optical element 53 (shown as a dot-dash line). It can be seen that the passband BP2 of the second filter I2 for a transmission coefficient greater than or equal to 80% is in the range from 430nm to 460nm, with a transmission peak at 445nm. It should be noted that the second optical filter I2 has other passbands outside the first range BP1, which does not affect the performance of the system, as will be described below. In [ Figure 3 ] In the non-limiting example in FIG. 1 , the optical element 53 is formed by 11 superimposed layers.

[0077] The set of filters I1 and I2 thus forms filter I, whose transmission spectrum has been superimposed on [ Figure 3 ] on the other transmission spectra of filters I1 and I2 in . It can therefore be seen that the spectrum of filter I therefore has only one wavelength range, specifically range BP2, for which the transmission coefficient is greater than 80%.

[0078] When the sunlight conditions in the vicinity of the vehicle are particularly bright, sunlight is therefore added to the light beam F2 received by the receiving module 3. The light from the sun in the visible spectrum is much brighter than the light from photometric functions such as daytime running lights. Therefore, the light beam F2 received by the receiving module 3 is initially composed of the light beam F1 emitted by the transmitting module 2 or by another similar transmitting module and sunlight. For the wavelength range in the visible range, the intensity level of this F2 light beam far exceeds the intensity level of the F1 light beam.

[0079] However, the combination of filters I1 and I2 minimizes the effect of the sun on beam F2 by eliminating all wavelengths of beam F2 except those in the second range BP2. This prevents saturation of the photodetector 32a receiving this beam F2, while filter I is not particularly complex or expensive.

[0080] It should also be noted that the filter I makes it possible to keep only the blue component of the beam F2, i.e. the component corresponding to the light emitted first by the light source 23, the yellow light being emitted with a longer response time due to the delay introduced by the photoluminescence. Therefore, performing the detection only on the basis of the blue light received by the receiving module 3 improves the resolution of the evaluation of the travel time of the beam F2 and / or the data transmission rate between the transmitting module and the receiving module 3.

[0081] The above description clearly explains how the invention achieves the stated objectives, namely to provide a motor vehicle system capable of performing communication or detection functions using visible light, wherein the signal-to-noise ratio is optimal in all weather conditions, including bright sunlight, and wherein the implementation complexity and costs are justified. These objectives are achieved in particular by means of a receiving module equipped with two filters, comprising: a first filter made using a lens made of an absorptive material and intended to eliminate a significant portion of the spectrum of this light beam; and a second interference filter, which selects a narrow band within the passband of the first filter.

[0082] In any case, the invention is not limited to the embodiments specifically described in this document and extends in particular to all equivalent devices and to any technically operable combination of these devices. In particular, other types of light sources than those described can be used, such as laser diodes, VCSELs or SLEDs. Photometric functions other than those described can also be performed, in particular low-beam lighting functions or position light signaling functions. Other configurations of the optical elements forming the second optical filter, such as flat plates, are also possible. Other materials can also be used to enable lenses or optical elements to obtain the same wavelength range or other wavelength ranges, or to additionally enable the first filter to be arranged upstream of the second filter.

Claims

1. A system (1) for a motor vehicle, comprising a receiving module (3) capable of receiving a light beam (F2), in, The receiving module comprises a basic acquisition module (32), wherein the basic acquisition module comprises a photodetector (32a) capable of converting the optical signal received by the basic acquisition module into an electrical signal, and is characterized in that the receiving module comprises an optical unit (31) arranged in front of the basic acquisition module, wherein the optical unit comprises: a lens (52), wherein the lens is made of an absorptive material to form a first optical bandpass filter (I1) capable of transmitting a first wavelength range (BP1); and an optical element (53), wherein the optical element is arranged to form a second optical interference filter (I2) capable of transmitting a second wavelength range (BP2) at least partially included in the first range and substantially narrower than the first range.

2. System (1) according to the preceding claim, in, The absorptive material of the lens (52) is selected such that the first range (BP1) is centered on wavelengths in the visible spectrum.

3. System (1) according to the preceding claim, in, The optical element (53) is arranged such that the width of the second range (BP2) is less than 30 nm.

4. System (1) according to the preceding claim, in, The optical element (53) comprises a stack of thin layers, each of which alternately has a high refractive index or a low refractive index.

5. System (1) according to one of the preceding claims, in, The lens (52) is a plano-convex lens, and the optical element (53) is a coating formed on a flat surface of the lens.

6. System (1) according to one of the preceding claims, in, The optical element (53) is a flat plate interposed between the lens (52) and the elementary acquisition module (32).

7. System (1) according to one of the preceding claims, in, The optical unit (31) comprises a plurality of lenses (51, 52), including the lens (52) forming the first optical filter (I1) and at least one further lens (51) made of a transparent material.

8. System (1) according to one of the preceding claims, It is characterized in that The receiving module (3) comprises a demodulation unit (33) connected to the photodetector (32a) and arranged to extract a data sequence from the electrical signal converted by the photodetector.

9. System (1) according to the preceding claim, It is characterized in that The system comprises a transmitting module (2), which comprises: a light emitting module (21) capable of emitting a light beam (F1), the spectrum of which has at least a portion in the second wavelength range (BP2); and a modulation unit (22), which is capable of receiving a data sequence and is arranged to modulate the emitted light beam using the received data sequence.

10. System (1) according to the preceding claim, in, The modulation unit (22) is arranged to generate a pulse width modulated control signal, modulate the control signal using the received data sequence, and use the modulated control signal to control the emission of the light beam (F1) by the light emitting module (21).

11. The system (1) according to claim 9 or 10, It is characterized in that The system comprises a computing unit (4) arranged to detect the presence of a data sequence modulating a light beam (F1) emitted by the transmitting module (2) from a data sequence extracted at the demodulation unit (33) from an electrical signal converted by a photodetector (32a) from a light beam (F2) received by the receiving module (3), and to determine a travel time between the emission of the emitted light beam and the reception of the received light beam.

12. The system (1) according to any one of claims 9 to 11, in, The transmitting module (2) is arranged so that the light beam (F1) fully or partially participates in the performance of a predetermined legally prescribed photometric function.

13. The lighting system (1) as claimed in one of the preceding claims, It is characterized in that The receiving module (3) is arranged in a headlight of the motor vehicle.

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