VEHICLE LIGHTING DEVICE, WITH FRONT-END LIGHT GUIDE WITH SPATIAL PHOTON DISTRIBUTION.

Abstract

A lighting device (LD) is fitted to a vehicle and comprises photon sources (PS) and a light guide (LG) with a rear end (E1) supplied with photons and a front end (E2) having a first extension in a first direction strictly greater than a second extension in a second direction perpendicular to the first and delivering guided photons that participate in a photometric function designed to illuminate the vehicle in the transverse and vertical directions, respectively, over minimum first and second lengths. This front end (E2) is installed in the vehicle with its first direction inclined at an angle between -45° and +45° with respect to the vertical direction of the vehicle, and is equipped with three-dimensional structures (ST) that induce a spatial distribution of the guided photons respecting the minimum first and second lengths.

Description

VEHICLE LIGHTING DEVICE, WITH FRONT-END LIGHT GUIDE WITH SPATIAL PHOTON DISTRIBUTION. The invention relates to vehicles, and more specifically to lighting devices fitted to vehicles that provide at least one photometric function. Many vehicles, generally automobiles, include at least one lighting device comprising at least one photon source and a light guide with a rear end supplied with photons by each photon source and a front end delivering guided photons from the rear end. Such a lighting device may optionally constitute an optical unit, in which case it also includes a housing delimiting an internal space containing each photon source and the light guide, and a lens fixedly attached to the front of the housing, or it may be part of an optical unit. In certain lighting devices, the front end of the light guide has a first extension along a first direction that is strictly greater than a second extension along a second direction perpendicular to this first direction, and the guided photons it emits participate in a photometric function defined by regulations (or legislation). The invention relates to the case where the photometric function must illuminate the vehicle along the vertical and transverse (horizontal) directions, respectively, over minimum first and second lengths. For example, in the case of a photometric reversing light function, current regulations generally require that the first minimum length (horizontal) be strictly greater than the second minimum length (vertical). Currently, to comply with this type of regulation, the light guide is installed in a position where the first direction is substantially parallel to the transverse (and therefore horizontal) direction of the vehicle, and the second direction is substantially parallel to the vertical direction of the vehicle. Thus, the larger of the sides of the front end of the light guide (transverse) ensures the larger of the two minimum lengths (namely the first), while the smaller of the sides of the front end of the light guide (vertical) ensures the smaller of the two minimum lengths (namely the second). Having the longest side of the front end positioned roughly parallel to the vehicle's transverse direction can create space constraints, especially when the housing is relatively small and / or has a complex shape and / or is obstructed along the same transverse direction (for example, by the presence of components performing at least one other photometric function). Furthermore, this can compromise the desired style or even prevent the establishment of a particular style altogether. The invention is intended, in particular, to improve the situation. In particular, it proposes for this purpose a lighting device, on the one hand, intended to equip a vehicle, and, on the other hand, comprising at least one photon source and a light guide, comprising a rear end supplied with photons by the (each) photon source and a front end having a first extension along a first direction strictly greater than a second extension along a second direction perpendicular to this first direction and delivering guided photons from the rear end and participating in a photometric function intended to illuminate along transverse and vertical directions of the vehicle respectively over first and second minimum lengths. This lighting device is characterized by the fact that the front end of its light guide is intended to be installed in the vehicle with its first direction inclined at an angle between -45° and +45° relative to a vertical direction of the vehicle, and is equipped with three-dimensional structures which induce a spatial distribution of the guided photons respecting the first and second minimum lengths. Thus, the longer side of the front end of the light guide can be installed substantially parallel to (or inclined relative to) the vertical direction of the vehicle, even when the first The minimum (transverse) length must be greater than or equal to the second minimum (vertical) length, which proves particularly advantageous when space constraints arise along the direction. transverse to the vehicle. The lighting device according to the invention may include other features which may be taken separately or in combination, and Specifically: the three-dimensional structures can be chosen from prisms, grooves, ribs and gadroons; it can include N photon sources, with N = 2, and the rear end of its light guide can include N input zones supplied with photons respectively by the N photon sources and distributing the incoming photons into a central part of the light guide, located between the rear and front ends, according to a law that is chosen according to the three-dimensional structures; it can include an electronic board on which each photon source is installed; each photon source can include at least one light-emitting diode (or LED); its light guide can be intended to participate in a photometric function chosen from a reversing light function, a brake light function and a turn signal function. The invention also proposes an optical unit for equipping a vehicle, comprising a housing delimiting an internal space, a lens fixedly attached to a front part of the housing, and a lighting device. of the type shown above and installed in the internal space of the case. For example, this optical unit can serve as a rear light for vehicle. The invention also proposes a vehicle, possibly of the automobile type, comprising at least one optical unit of the type of that presented above. Other features and advantages of the invention will become apparent at Examination of the detailed description below, and the attached drawings (obtained using CAD / CAM (“Computer-Aided Design / Computer-Aided Manufacturing”), hence the seemingly discontinuous nature of some lines), in which: Figure 1 schematically and functionally illustrates, in a perspective view from the front, a small part of an example optical block equipped with a lighting device according to the invention, and Figure 2 illustrates schematically and functionally, in a perspective view, an example of an embodiment of a lighting device according to the invention. The invention aims in particular to provide a DE lighting device intended to equip a vehicle in order to ensure at least one photometric function. In what follows, we consider, by way of non-limiting example, that the DE lighting device is intended for use in a motor vehicle. However, the invention is not limited to this type of vehicle. It relates to any type of vehicle equipped with at least one DE lighting device that must perform at least one photometric function. Furthermore, in the following, it is assumed, by way of non-limiting example, that the DE lighting device is intended to be part of a vehicle optical unit (BO). However, this is not mandatory. Indeed, a DE lighting device, according to the invention, may optionally constitute an optical unit, and in this case, it also comprises a housing defining an internal space containing its components participating in the (each) photometric function, and a lens fixedly attached to the front part of the housing. Furthermore, in the following, the optical unit is considered, by way of non-limiting example, to be a rear light. For instance, this rear light could be part of a vehicle's tailgate. But the optical unit could also be a front signal light. In Figures 1 and 2, the X direction is the longitudinal direction of vehicle V, which is parallel to the lateral sides containing the side doors; the Y direction is the transverse direction of vehicle V, which is perpendicular to the lateral sides and to the longitudinal direction X, and the direction Z is the vertical direction of the vehicle V, which is perpendicular to the longitudinal direction X and transverse direction Y. Figure 1 schematically illustrates a small part of an example of an optical block BO (here a rear light) equipped with a lighting device DE according to the invention. Although it does not appear in Figure 1, the optical block BO comprises a housing delimiting an internal space housing (here) the lighting device DE and a mask MA, and a glass fixedly attached to a front part of the housing. The glass is securely attached (for example by gluing or welding) and in a watertight manner to the front part of the case. It can be made of transparent plastic (or synthetic material) or glass, and may optionally be colored, at least partially, for example in red or orange. As illustrated in Figure 2, a lighting device DE, according to the invention, comprises a light guide GL and at least one photon source SP. For example, each SP photon source may include at least one light-emitting diode (LED). Alternatively, each photon source may include at least one laser diode, a gas laser, or a lamp (or bulb). As illustrated (but not limited to) in Figure 2, each photon source can be mounted on a CE-certified electronic board housed within the optical block's internal space. This CE-certified electronic board can, for example, be a printed circuit board (PCB). Furthermore, this CE-certified electronic board may also be part of the DE illumination device. Note that in the example illustrated (non-exhaustively) in Figure 2, the lighting device DE comprises three photon sources SP. However, it can comprise any number of photon sources SP, provided that this number is greater than or equal to one (1). The GL light guide includes a powered E1 rear end in photons by the (each) photon source SP, a front end E2 opposite the rear end E1, and a central part PC interposed between the rear ends E1 and front end E2. In the example illustrated non-limitingly in Figure 1, only the front end E2 of the light guide GL is visible from outside the optical block BO, because it is located just in front of an opening defined in the mask MA of the optical block BO and crossed by the central part PC of the light guide GL. Preferably, this GL light guide is of the so-called "flat" type. It can, for example, be made by molding a material such as polycarbonate (or PC) or polymethyl methacrylate (or PMMA). The front end E2 has a first extension e1, along a first direction d1, which is strictly greater than a second extension e2, along a second direction d2 perpendicular to this first direction d1. This front end E2 emits photons that have been guided from the rear end E1 (via the central part PC) and that participate in a photometric function. This function must illuminate along the transverse Y and vertical Z directions of the vehicle, respectively, over minimum lengths Im1 and Im2. For example, the GL light guide can be intended to participate in a photometric reversing light function. But it could also be intended to participate in a photometric brake light function or turn signal (or indicator) or position light or daytime running light (or DRL (for "Daytime running Light (or Lamp)" - light signaling automatically illuminated when the vehicle is started during the day)). The front end E2 of the GL light guide is also intended to be installed in the vehicle with its first direction d1 inclined at an angle between -45° and +45° with respect to the vertical direction Z, and is equipped with three-dimensional structures ST which induce a spatial distribution of the guided photons respecting the first Im1 and second Im2 minimum lengths. When the photometric function is a reversing light function, the first minimum length Im1 (transverse) can be greater than or equal to the second minimum length Im2 (vertical). In this case, the longer side of the front end E2 (along d1) provides the shorter of the two minimum lengths (namely the second Im2), while the shorter side of the front end E2 (along d2) provides the longer of the two minimum lengths (namely the first Im1). Therefore, reversing illumination is provided over a significant distance along the second direction d2 on at least one of the two sides, right and left. Thanks to the invention, the longer side of the front end E2 of the GL light guide can be installed substantially parallel to the vertical direction Z of the vehicle (or inclined between -45° and +45° relative to it (Z)), even when the first minimum length Im1 must be greater than or equal to the second minimum length Im2. This proves particularly advantageous when space constraints arise along the transverse direction Y of the vehicle (for example, due to the presence of elements performing at least one other photometric function). Furthermore, this can avoid compromising the desired styling and allows for the creation of distinctive styles different from those already available.Furthermore, this can provide sufficient illumination in low light conditions towards the rear of the vehicle so that a driver assistance system can accurately detect objects and their attributes in images provided by a rear camera. The types and / or shapes of the three-dimensional ST structures are chosen based on the spatial distribution of the guided photons, and therefore on the minimum lengths of the first Im1 and second Im2, taking into account the inclination angle of the first direction d1 relative to the vertical direction Z and the first e1 and second e2 extensions. The configuration (type and shape) of a second leading edge E2 is determined by calculation, for example using the software tool speos® or lumiscave®. For example, and as illustrated (but not limited to) in Figure 2, three-dimensional ST structures can be prisms. Alternatively, they can be grooves, ribs, or cove-shaped (semi-cylinders). circulars), in particular. It should be noted that within a second front end E2, there can be three-dimensional structures ST having different types and / or different shapes. In other words, a second front end E2 can contain three-dimensional structures ST of a single type and identical or different shapes, or three-dimensional structures ST of at least two different types (each type having a single shape), or even three-dimensional structures ST of at least two different types (each type having several different shapes). Thus, in the example illustrated (but not limited to) in Figure 2, the second front end E2 comprises a front face FV which includes three-dimensional structures ST of a first type with a first shape, and a lateral face FL extending from the front face FV and including three-dimensional structures ST of a second type with a second shape. This lateral face FL is intended here to deliver light at the end of a photometric grid, typically at - / + 45°. For example, the three-dimensional structures ST can be defined during the molding of the light guide GL, or during an additional step. This latter step might, for example, include laser or chemical etching, or pad printing. It should also be noted that when the lighting device includes N photon sources SP, with N = 2, the rear end E1 of the light guide GL can include N entrance zones ZE supplied with photons respectively by the N photon sources SP, as in the example illustrated non-limitingly in figures 1 and 2. In this case, each entrance zone ZE is arranged so as to distribute the incoming photons in the central part PC of the light guide GL according to a law which is chosen according to the three-dimensional structures ST. To achieve this, each entry zone ZE can, as illustrated (but not limited to) in Figure 2, have a shape that widens (or flares) from back to front in order to progressively increase the reflection angles of the incoming photons and thus induce a large angular dispersion of the trajectories of the photons arriving in the central part PC of the GL light guide and heading towards the front end E2. To amplify this angular dispersion, each entrance zone ZE can, as illustrated (though not exhaustively) in Figure 2, include, on the side of the associated photon source SP, an internal cavity CI that receives the photons generated by the latter (SP). It will be understood that this internal cavity CI causes multiple reflections of the incoming photons, which initially induces a relatively large angular dispersion of the photon trajectories at the entrance of the widening (or flared) portion.

Claims

DEMANDS 1. Lighting device (ED) for a vehicle, said device (ED) comprising at least one photon source (SP) and a light guide (GL), comprising a rear end (E1) supplied with photons by said photon source (SP) and a front end (E2) having a first extension along a first direction strictly greater than a second extension along a second direction perpendicular to said first direction and delivering guided photons from said rear end (E1) and participating in a photometric function intended to illuminate along transverse and vertical directions of said vehicle respectively over first and second minimum lengths, characterized in that said front end (E2) of the light guide (GL) is intended to be installed in said vehicle with its first direction inclined at an angle between -45° and +45° with respect to a vehicular direction of said vehicle,and is equipped with three-dimensional structures (ST) inducing a spatial distribution of guided photons respecting the aforementioned first and second minimum lengths.

2. Lighting device according to claim 1, characterized in that said three-dimensional structures are selected from prisms, grooves, ribs and gadroons.

3. Lighting device according to claim 1 or 2, characterized in that it comprises N photon sources (SP), with N > 2, and in that said rear end (E1) of the light guide (GL) comprises N entry zones (ZE) supplied with photons respectively by said N photon sources (SP) and distribute said incoming photons into a central part (PC) of said light guide (GL), located between said rear (E1) and front (E2) ends, according to a law chosen according to said three-dimensional structures (ST).

4. Lighting device according to any one of claims 1 to 3, characterized in that it comprises an electronic board (CE) on which each photon source (SP) is installed.

5. Lighting device according to any one of claims 1 to 4, characterized in that each photon source (SP) comprises at least one light-emitting diode.

6. Lighting device according to any one of claims 1 to 5, 5 characterized in that said light guide (GL) is intended to participate in a photometric function selected from a reversing light function, a brake light function and a direction change indicator function.

7. Optical unit (OU) intended to equip a vehicle and comprising a housing delimiting an internal space and a lens fixedly attached to a front part of said housing, characterized in that it further comprises a lighting device (ED) according to one of the preceding claims, installed in said internal space.

8. Optical unit according to claim 7, characterized in that it 15 constitutes a rear light.

9. Vehicle, characterized in that it comprises at least one optical unit according to claim 7 or 8.

10. Vehicle according to claim 9, characterized in that it is of the automobile type.

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