LIGHTING MODULE FOR A MOTOR VEHICLE WITH DISTANCE MEASURING FUNCTION

Description

[0001] The invention relates to a lighting module for a motor vehicle equipped with a telemetry function.

[0002] Typically, a lighting module that performs the functions of a vehicle's low beam and / or high beam consists of several light-emitting diodes (LEDs) as a light source and one or more reflectors per function. A lens may be added to the reflector in some cases.

[0003] Furthermore, more and more vehicles are equipped with a LIDAR (light detection and ranging or laser imaging detection and ranging) type telemetry system that can measure one or more distances using a laser pulse. This type of system typically includes one or more laser sources and a receiver sensitive to the laser wavelength. The laser beams are directed onto the object whose distance is to be measured via an optical transmitting element. A receiving optical element collects the light reflected by the object and focuses it onto the receiver.

[0004] In most vehicles, the lighting module and the telemetry system are separate and distinct modules.

[0005] However, the range performance of the telemetry system, especially the LIDAR type, is directly related to the dimensions of the receiver optics. The larger the optics, the more light the detector receives. The performance of the illumination function is also directly related to the dimensions of the optical element. The larger the optical element, the more light it can collect and send onto the road. In addition, the illuminated areas and the areas in which the telemetry system makes measurements are the same. The orientation and dimensioning of the optical elements therefore have a large number of common points.Thus, the pooling of the optical elements of the telemetry system and of a lighting module can allow an increase in the size of the optical elements in order to improve the performance of both the lighting and the telemetry system (more reliable measurement because less disturbed by dirt on the external surface of the system). Thus, document US10766401B1 discloses a lighting module for a motor vehicle comprising a light source coupled to a reflector to provide a lighting function along a first optical path and a telemetry detector collecting laser light via the same reflector. Although the light beams of the two functions follow different optical paths, the use of a single reflector can impair the accuracy of the telemetry function.Since the concave surface of the reflector is designed primarily both to collect light and send it onto the road for the illumination function and to collect the laser radiation and send it onto the detector, not all of the laser radiation may be sent entirely onto the object to be measured, so that part of this laser radiation is not reflected by the object to be measured to the detriment of the measurement accuracy. Another illumination module is known from DE 10 2017 109905 A1.

[0006] There is therefore a need to improve the accuracy of a telemetry function integrated into a lighting module.

[0007] For this purpose, a motor vehicle lighting module equipped with a telemetry function is proposed, the module comprising a housing closed by a transparent or translucent wall inside which are housed: - at least one light source of a lighting function emitting light rays along a first optical path, - at least one light source of the telemetry function emitting light rays along a second optical path, - at least one detector of a telemetry function, in particular a single detector, configured to detect light rays, in particular light rays coming from at least one object to be measured, - a single reflector configured to reflect the light rays emitted by the at least one light source of the lighting function along a lighting direction and to return light rays coming from at least one object to be measured located on the road towards the detector.

[0008] According to the invention, the different light sources and the detector are located in the same focal plane of the reflector and the reflector comprises at least one specific reflection zone associated with each light source of the telemetry function, each specific zone having a specific orientation different from the orientation of the rest of the deflector and configured to return to one of the objects to be measured the light beam emitted by the associated light source of the telemetry function, in particular in its entirety.

[0009] This arrangement makes it possible to send the entire light beam emitted by each associated light source of the telemetry function onto an object to be measured and thus to improve the accuracy of the telemetry measurement. Due to the specific orientation of each specific reflection zone, the surface of the reflector thus becomes irregular, each specific reflection zone protruding from the rest of the surface of the reflector, which may have a concave surface. According to the invention, each specific reflection zone has a concave surface distinct from a concave surface of the rest of the reflector, of different orientation. This concave surface also has specific dimensions corresponding to the dimensions of the intersection of the light beam emitted by the at least one associated light source with the surface of the reflector.

[0010] This can be implemented both in lighting modules comprising only a single optical element (the reflector) and in lighting modules comprising several optical elements, typically a reflector and at least one lens. Thus, in one embodiment, the lighting module further comprises, inside the housing, at least one lens located between the reflector and the transparent and translucent wall.

[0011] Advantageously, each specific area of ​​reflection can present: a surface defined by the intersection of a concave surface of the reflector with the light beam emitted by the light source of the associated telemetric function, a center defined as the point of intersection of a first direction with said concave surface of the reflector, this first direction corresponding to the direction of the light beam emitted by the light source of the associated telemetric function.

[0012] The orientation of a specific area then corresponds to a straight line normal to the surface of this specific area, which is the bisector of the angle formed between the first direction and a second direction, the second direction being defined as (i) a direction connecting an object to be measured to the center of the surface when the lighting module is without a lens or (ii) a direction passing through the center and which is the transform of a direction connecting the optical center of the at least one lens to the object to be measured by the optical transfer function of said lens when the lighting module is provided with at least one lens.

[0013] The illumination module may comprise at least two light sources of the ranging function and the reflector may comprise a specific reflection zone associated with each of these light sources. This may make it possible to aim at different objects to be measured, in other words to measure the distances of objects located in different directions, for example an object located above the horizon and an object located below the horizon.

[0014] Thus, in one embodiment, the lighting module may comprise at least two light sources of the telemetry function and the reflector then comprises (i) at least one specific reflection zone associated with one of the light sources and oriented to return the emitted light beam towards one of the objects to be measured and (ii) at least one other specific reflection zone associated with another of the light sources and oriented to return the emitted light beam towards another of the objects to be measured.

[0015] It is in particular possible to provide one or more light sources and associated specific reflection zones for measuring the distance of a first object and one or more other light sources and associated specific reflection zones for measuring the distance of a second object.

[0016] In order to simplify the manufacture of the module and its size, the lighting module may comprise a single electronic control card and at least one light source of the lighting function, the at least one source of the telemetry function and the detector are then fixed and electrically connected to the electronic control card, in particular on the side of the same face of the electronic control card.

[0017] Typically, the at least one light source of the lighting function is a light-emitting diode and the at least one source of the telemetry function is a laser diode, the latter emitting, for example, pulses of infrared light. The detector may be a photosensitive detector, for example of the photonic type, converting photons into electrons.

[0018] The invention also relates to a method of manufacturing a lighting module according to the invention, comprising: (A) a step of determining the at least one specific reflection zone of the reflector, in which, for a reflector having a predefined concave surface, for each light source of the telemetry function: (a) a surface defined by the intersection of the concave surface of the reflector with the light beam emitted by the light source of the associated telemetry function is determined, (b) the center of said zone is determined as the point of intersection of a first direction with said concave surface of the reflector, this first direction corresponding to the direction of the light beam emitted by the light source of the associated telemetry function, (c) the orientation of said zone is determined so that the normal to the surface of the zone passing through the center is the bisector between the first direction and a second direction,the second direction being defined as (i) a direction connecting an object to be measured to the center of the surface when the lighting module is without a lens or (ii) a direction passing through the center which is the transform of a direction connecting the optical center of the at least one lens to the object to be measured by the optical transfer function of said lens when the lighting module is provided with at least one lens, (B) a step of manufacturing a reflector, in which a reflector is produced having the predefined concave shape and at least one specific reflection zone whose position and surface are defined by the center determined in step (b) and the surface determined in step (a) and whose orientation is the orientation determined in step (c), the reflector having an irregular surface,each specific area of ​​reflection protruding from the rest of the reflector's surface. This orientation is thus different from the orientation of the rest of the reflector's surface.

[0019] These steps can be implemented for a lighting module in which the positions of each source, reflector and detector are predefined, and the surface of the reflector, typically concave, is predefined.

[0020] In one embodiment, the manufacturing method may comprise, prior to steps (A) and (B), a positioning step during which the at least one light source of a lighting function is positioned on an electronic control card and the reflector is positioned so as to perform said lighting function along a first optical path, in particular so as to reflect the light rays emitted by the at least one light source of the lighting function along the first optical path, a step of determining the position of an object to be measured, in particular where it is determined whether the object to be measured is above or below the horizon, a step of positioning the detector of the telemetry function on the electronic control card, in particular in a position receiving light rays reflected by the detector and coming from the at least one object to be measured located on the road, and,the determination step (A) is implemented by placing the at least one light source of the telemetry function in a free position of the electronic control card.

[0021] In particular, it is possible to choose to position the detector in a position on the electronic card sufficiently far from at least one light source of the lighting function to avoid heating the detector.

[0022] Step (A) may also be implemented so as to position the at least one light source of the telemetry function at a sufficient distance from the detector to avoid its heating.

[0023] In another embodiment, the manufacturing method may further comprise, prior to steps (A) and (B), a step of positioning on an electronic control card the at least one light source of a lighting function, the detector of the telemetry function and the at least one light source of the telemetry function, a step of positioning the reflector so as to carry out said lighting and telemetry measurement function, in particular so as to reflect the light rays emitted by the at least one light source of the lighting function along a first optical path and to return light rays coming from at least one object to be measured located on the road in the direction of the detector, a step of determining the position of the object to be measured, in particular where it is determined whether the object to be measured is above or below the horizon.

[0024] This allows the specific reflection zone(s) to be adapted to an object to be measured for the same electronic card. In other words, for different applications and types of objects to be measured, it is thus possible to use a single electronic card on which the light sources and the detector are always in the same positions and only modify the reflector and more particularly the specific reflection zone(s).

[0025] The invention finally relates to a motor vehicle comprising at least one lighting module according to the invention or obtained by the manufacturing method according to the invention.

[0026] The invention is now described with reference to the accompanying non-limiting drawings, in which: There [ Fig. 1 ] represents a schematic side view of a lighting module according to one embodiment, The [ Fig. 2] represents a schematic side view of a lighting module according to another embodiment, The [ Fig. 3 ] represents an enlarged schematic side view of the reflector of the lighting module shown figure 1 , There [ Fig. 4 ] represents an enlarged schematic front view of the reflector of the lighting module shown figure 1 . There [ Fig. 5 ] represents a schematic side view of a lighting module according to another embodiment.

[0027] In the figures, the same elements are designated by the same references.

[0028] There figure 1 schematically represents a lighting module 10 comprising a housing 11 closed by a transparent or translucent wall 12.

[0029] Inside the case 11 are housed at least one light source 13, here only one, of a lighting function emitting light rays along a first optical path C1, at least one light source 14, here only one, of the telemetry function emitting light rays along a second optical path C2, at least one detector 15 of the telemetry function configured to detect light rays, a single reflector 16 configured to reflect the light rays emitted by the at least one light source of the lighting function along a lighting direction and to return light rays coming from at least one object O1 to be measured located on the road towards the detector.

[0030] Object O1 is located here above horizon H.

[0031] The reflector 16 typically has a concave surface, the shape of which is calculated so as to reflect the light rays emitted by the light source 13 of the lighting function along the first optical path and to return light rays coming from the object to be measured O1 located on the road towards the detector 15. On the figure 1 , the optical path followed by the light rays coming from the object O1 are designated by the reference O1. The different light sources 13, 14 and the detector 15 are located in the same focal plane of the reflector, here on the same electronic card 17, in particular on the side of the same face thereof. This electronic card is here mounted on a heat dissipation device 18 and therefore supplies each of the elements 13, 14, 15.

[0032] The reflector 16 further comprises a specific reflection zone 20 associated with the light source 14 of the telemetry function, this specific zone having a specific orientation n different from the orientation of the rest of the deflector and configured to return to the object O1 to be measured the light beam emitted by the light source 14, in particular the entirety of this light beam.

[0033] There figure 2 does not differ from the figure 1 than by the position of the object to be measured designated here by the reference O2 and located below the horizon H.

[0034] There Figure 5 does not differ from the figure 1 than by the presence of a lens 19 inside the housing 11, between the reflector 16 and the transparent or translucent wall 12.

[0035] Whatever the embodiment, each specific reflection zone 20 presents, as visible on the Figures 3 and 4 : a surface S defined by the intersection of a concave surface of the reflector 16 with the light beam F emitted by the light source of the associated telemetric function, in other words with the light cone of the light beam, a center C defined as the point of intersection of a first direction d1 with said concave surface of the reflector 16, this first direction corresponding to the direction of the light beam emitted by the light source of the associated telemetric function, namely the axis of the light beam.

[0036] The orientation n of the specific zone 20 then corresponds to a straight line normal to the surface of this specific zone, which is the bisector of the angle formed between the first direction d1 and a second direction d2. In the examples of figures 1 And 2 , the second direction is defined as a direction connecting the object to be measured (O1 or O2) to the center C of the surface. In the example of the Figure 5, this second direction d2 is a direction passing through the center C and which is the transform of a direction d2 connecting the optical center of the lens 19 to the object to be measured by the optical transfer function of this lens.

[0037] It is thus understood that the entirety of the light source 14 is sent by the specific zone towards the object to be measured and that the specific zone, due to its particular orientation, defines a surface projecting relative to the rest of the concave surface of the reflector, as visible in the figures.

[0038] It should be noted that in the case where the object to be measured is located above the horizon ( figures 1 , 3, 5 ), the telemetry system can be combined with a low beam lighting function. In the case where the object to be measured is located below the horizon ( figure 2 ), the telemetry system can be combined with a high beam lighting function.

[0039] This distinction allows the same optics and electronic card to be used for the lighting and telemetry functions.

[0040] The invention makes it possible to exploit a property of stigmatic optics: light rays coming from infinity (>10m) focus in a plane called the focal plane. In the invention, the light source(s) of the lighting function are in this focal plane, as are all the other components positioned on the electronic board. Each point in the focal plane of an optic corresponds to a particular direction for the light coming from infinity. Therefore, in the case of dipped beam headlights, the light being below the horizon, the corresponding part in the focal plane is the light source of the lighting function. The light backscattered by the object (which is outside the illuminated area) will concentrate next to the light source of the lighting function in the focal plane, where the detector can be placed.

[0041] The light source of the telemetry function is placed on the same electronic board as the light source of the illumination function and the detector. This light source only needs a very small flat optical surface (in order to keep the properties of the LASER light) of the order of a few mm 2< , the specific area is oriented so that its normal is the bisector between the axis of the Laser coming from the electronic component and the axis of the desired laser output.

[0042] In the case of the integration of a telemetry function, typically of the LIDAR type, in a lighting module whose main functionality is to perform the dipped beam and main beam function(s), the procedure described below may be used to adapt the shape and dimensions of the specific reflection zone(s) of the reflector.

[0043] Two cases can be considered: a single light source for the telemetry function which will measure a single object (single-point telemetry). a plurality of light sources for the telemetry function, which will simultaneously measure a series of object points (for example, use of a VCSEL type source: Vertical Cavity Surface Emitting Laser Diode). It should be noted that the use of a plurality of light sources for the telemetry function makes it possible to measure object points located above the horizon and object points located below the horizon in the same lighting module.

[0044] For each of the cases, the lighting module may have a lens 19 or not. In the case of a lighting module without a lens, we speak of a single optical component module typically comprising a bowl-shaped reflector with a smooth or faceted surface. In the case of a lighting module with a lens, we speak of a multi-optical component module typically comprising an elliptical reflector (first component) and a lens made of transparent material (second component).

[0045] So there are four main configurations, for which we have detailed below how to adapt the optical surface so that the emission part of the telemetry system is as efficient as possible while impacting the lighting functions as little as possible.

[0046] The sources are electronic components that are soldered onto a single electronic board (printed circuit board). The light beams (mean light direction) from the different sources are emitted orthogonally to the electronic board.

[0047] It is further considered that the transparent or translucent wall 12 of the lighting module is calculated to have the most neutral optical power possible. If this is not the case, it can then be considered as an additional optical element. 1) Single-point telemetry with a mono-optical system

[0048] The light source 14 of the telemetry function is for example a LASER which is a collimated light source (all the rays are almost parallel) which sends a light beam orthogonally to the electronic card on which the LED(s) of the lighting function are also soldered and sending its light from the same side as the LEDs.

[0049] The optical component of the lighting module is the smooth or faceted concave reflector 16 whose orientation of the surface or facets is calculated in order to achieve the light distribution or a part of the light distribution of one or more lighting functions by reflecting the light from one or more light sources 13, typically LEDs. We will not specify here the calculation of this concave surface, well known to those skilled in the art.

[0050] The specific reflector area to be modified (denoted S) is determined by the intersection of the concave surface of the reflector 16 (before modification) and the LASER light beam (denoted F). The center (denoted C) is given by the axis (denoted d1) of the LASER.

[0051] The dimensions of the zone can be determined either by using the divergence of the LASER which is given by the manufacturer of the LASER source or by calculating the Waist of the LASER beam given by equation 1: w z = w 0 1 + z z 0 2 With : z the propagation axis of the LASER w(z) the beam width at position zw 0 the beam width leaving the component (minimum value) z 0 the origin of the z axis defined by equation 2: z0=πw02λ

[0052] Where λ is the central wavelength of the LASER.

[0053] Once the zone S of the reflector to be modified has been identified, its orientation n is determined in the following manner: the normal n to the surface of the zone 20 is oriented so as to be the bisector of the angle formed by the first direction noted d1 and a second direction noted d2.

[0054] The second direction d2 is the direction of the point we want to measure. It is the line passing through the center C and through the point (the object) we want to measure.

[0055] Note that if d2 passes through a solid element of the lighting module that can block the light, it is possible to move point C along the first direction d1. Point C can also be translated due to manufacturing constraints. 2) Multipoint telemetry with a mono-optical system

[0056] The notations are identical to the previous case.

[0057] Here the source of the ranging function is a VCSEL which is an array of LASERs that can be parallel or divergent to each other.

[0058] The principle is the same as in the previous case except for the following points: The dimensions of the surface S are defined by the outermost LASERs of the VCSEL with the same method as for a single LASER. Only the outer limit will be kept so as to obtain a convex shape in the mathematical sense. d2 is defined in the same way as for the LASER but by matching each measurement point / direction to one of the LASERs of the VCSEL.

[0059] The calculation of the orientation n of each zone 20 is identical but we take the directions d1 and d2 specific to each LASER. Therefore, we have a specific zone 20 defined by each LASER individually, presenting its own orientation.

[0060] These specific zones being contiguous, they can form a faceted surface (each zone corresponding to a facet) whose number of facets is at least equal to the number of measurement points, each facet being oriented as explained above, or they can form a smooth surface with sub-zones corresponding to the sub-zones of each LASER and oriented individually according to their own direction. 3) Single-point ranging with a multi-optical system (figure 5)

[0061] The first optical component is a reflector 16 as in 1).

[0062] The difference is made on the direction d2 used in the calculation, here the direction d2 always passes through C but it is not directly the direction / measurement point which gives this direction d2.

[0063] In this case, the measurement can only be made in one direction, which corresponds to a point far from the optics. The measuring point will therefore be at a very large distance in front of the diameter of the lens of the optical system so that the variation in angle between 2 rays each coming from one end of the lens towards a measuring point is negligible. This allows, from the distant measuring point and the center C of the lens 19, to obtain a good approximation of the measuring direction, noted 2.

[0064] The optical element(s) between C and the output of the system can be summarized by a function which transforms one direction (object side) into another direction (image side) called Optical Transfer Function (OTF).

[0065] The FTO is known because it is used to calculate the photometry of the lighting function. It can also be obtained via the Snell-Descartes and reflection laws.

[0066] Knowing the measurement direction of the image side and the FTO, we can determine the direction of the object side by the principle of inverse return of light.

[0067] The direction on the object side passing through point C then defines direction d2. The orientation n is then determined as explained in point 1). 4) Multi-point LIDAR with a multi-optical system.

[0068] We then proceed as described in point 2) but with the method of calculating the directions d2 of each LASER of the VSCEL described in point 3).

[0069] The invention is particularly suitable for a LIDAR type telemetry function, preferably other than a scanning LIDAR, the latter requiring additional optical components making their integration into a lighting module more complex.

Claims

1. Motor-vehicle lighting module (10) equipped with a range-finding function, the module comprising a housing (11) closed by a transparent or translucent wall (12) and inside of which are housed: - at least one light source (13) of a lighting function emitting light rays along a first optical path, - at least one light source (14) of the range-finding function emitting light rays along a second optical path, - at least one detector (15) of the range-finding function configured to detect light rays, - a single reflector (16) configured to reflect the light rays emitted by the at least one light source of the lighting function in a lighting direction and to steer light rays originating from at least one object to be measured located on the road in the direction of the detector, the various light sources and the detector being located in the same focal plane of the reflector and the reflector (16) comprising at least one specific reflection zone (20) associated with each light source (14) of the range-finding function, each specific zone (20) having a specific orientation that is different from the orientation of the rest of the deflector and that is configured to steer towards one of the objects to be measured the light beam emitted by the associated light source of the range-finding function, characterized in that the reflector has an irregular surface, each specific reflection zone protruding from the rest of the surface of the reflector.

2. Motor-vehicle lighting module (10) according to Claim 1, further comprising, inside the housing (11), at least one lens (19) located between the reflector (16) and the transparent and translucent wall (12).

3. Motor-vehicle lighting module (10) according to Claim 1 or 2, wherein each specific reflection zone has: - a surface defined by the intersection of a concave surface of the reflector with the light beam emitted by the light source of the associated range-finding function, - a centre defined as the point of intersection of a first direction with said concave surface of the reflector, this first direction corresponding to the direction of the light beam emitted by the light source of the associated range-finding function, and the orientation of a specific zone corresponds to a straight line normal to the surface of this specific zone, which is the bisector of the angle made between the first direction and a second direction, the second direction being defined as (i) a direction connecting an object to be measured to the centre of the surface when the lighting module is devoid of lens or (ii) a direction passing through the centre and which is the transform of a direction connecting the optical centre of the at least one lens to the object to be measured by the optical transfer function of said lens when the lighting module is provided with at least one lens.

4. Motor-vehicle lighting module (10) according to any of the preceding claims, comprising at least two light sources of the range-finding function and the reflector comprises (i) at least one specific reflection zone associated with one of the light sources and oriented so as to steer the emitted light beam towards one of the objects to be measured and (ii) at least one other specific reflection zone associated with another of the light sources and oriented so as to steer the emitted light beam towards another of the objects to be measured.

5. Motor-vehicle lighting module (10) according to any of the preceding claims, characterized in that it comprises a single electronic control board (17) and in that the at least one light source of the lighting function, the at least one source of the range-finding function and the detector are fastened and electrically connected to the electronic control board.

6. Process for manufacturing a lighting module according to any of the preceding claims, comprising: (A) a step of determining the at least one specific reflection zone of the reflector, in which, for a reflector having a predefined concave surface, for each light source of the range-finding function: (a) a surface defined by the intersection of the concave surface of the reflector with the light beam emitted by the light source of the associated range-finding function is determined, (b) the centre of said zone is determined as the point of intersection of a first direction with said concave surface of the reflector, this first direction corresponding to the direction of the light beam emitted by the light source of the associated range-finding function, (c) the orientation of said zone is determined so that the normal to the surface of the zone passing through the centre is the bisector between the first direction and a second direction, the second direction being defined as (i) a direction connecting an object to be measured to the centre of the surface when the lighting module is devoid of lens or (ii) a direction passing through the centre which is the transform of a direction connecting the optical centre of the at least one lens to the object to be measured by the optical transfer function of said lens when the lighting module is provided with at least one lens, (B) a step of manufacturing a reflector, in which a reflector is produced that has the predefined concave shape and at least one specific reflection zone the position and surface of which are defined by the centre determined in step (b) and the surface determined in step (a) and the orientation of which is the orientation determined in step (c), the reflector having an irregular surface, each specific reflection zone protruding from the rest of the surface of the reflector.

7. Manufacturing process according to Claim 6, further comprising, prior to steps (A) and (B), - a positioning step in which the at least one light source of a lighting function is positioned on an electronic control board and the reflector is positioned so as to perform said lighting function along a first optical path, - a step of determining the position of an object to be measured, - a step of positioning the detector of the range-finding function on the electronic control board, - a step of positioning the reflector so as to perform said lighting function and the range-finding function, and - determining step (A) is implemented by placing the at least one light source of the range-finding function in a free position on the electronic control board.

8. Manufacturing process according to Claim 6, further comprising, prior to steps (A) and (B), - a step of positioning on an electronic control board the at least one light source of a lighting function, the detector of the range-finding function and the at least one light source of the range-finding function, - a step of positioning the reflector so as to perform said lighting function and range-finding measurement, - a step of determining the position of the object to be measured.

9. Motor vehicle comprising at least one lighting module according to one of Claims 1 to 5.