LIGHTING DEVICE WITH CURVED FIBER GUIDES

Description

Technical field of the invention

[0001] The invention relates to lighting devices which comprise N light guides associated with N photon sources, with N ≥ 1, and which are intended to participate in the realization of at least one photometric function. State of the art

[0002] In what follows, "photometric function" means a photometric signaling function, a photometric lighting function, or a photometric light effect function, possibly decorative.

[0003] In certain fields, such as vehicles, possibly of the automotive type, lighting devices are used comprising N light guides, each having a first part receiving photons generated by an associated source through an end face and a second part having a front face through which photons from this first part exit, with N ≥ 1. The N light guides and the N associated sources are generally housed in an internal housing (or cavity) which is defined by a casing and a glass located in front of the second parts of the N light guides.

[0004] It should be noted that such lighting devices may be part of (or constitute) optical units (front or rear) of vehicles responsible for providing at least one photometric function. In this case, the photometric function may, for example, be a signaling function, such as a daytime running light (or DRL – a light signal that automatically illuminates when the vehicle is started during the day), a turn signal (or indicator) function, or a position light function.

[0005] When the second part of each light guide has a curved (or angled) sub-section, the end face of the first part and the associated light source end up positioned approximately on the axis of this curved sub-section. Consequently, the front face of each curved sub-section of a second part constitutes a "hot spot" which, to a person standing in front of it, appears noticeably brighter than the sub-section of the second part that follows this curved sub-section, even though a relatively homogeneous illumination on the visible front face of this second part is desired. This results from the fact that photons entering through the end face of the first part reach the curved sub-section after a small number of reflections at obtuse angles, which are also large, and can therefore exit at this curved sub-section, notably through reflections or diffractions, creating light leaks.

[0006] To prevent these unwanted light leaks (or escaping light), it is possible to install a mask (or cover) locally against each angled sub-section. However, this results in a significant additional cost to the lighting system.

[0007] It is also possible to use a two-tone (crystal / black) mirror in which each black area is designed to conceal a technical component and / or at least part of at least one angled sub-section, in order to prevent photons emitted by each angled sub-section from passing through the mirror and thus creating a visible hot spot. However, this has a negative impact on the style and / or perceived quality of the lighting fixture, as a person standing in front of it sees a large, opaque black area without understanding why it is there when it is not in operation.

[0008] Furthermore, the prior art is known from documents EP3821169B1, EP3650745B1, US2016121782A1, EP3845802A1 and US2019283663A1. The invention therefore aims, in particular, to improve the situation. Presentation of the invention

[0009] In particular, it offers a lighting system for a vehicle comprising: N light guides, each comprising a first part receiving photons generated by an associated source through an end face and a second part comprising a front face through which photons from this first part exit, with N ≥ 1, the first part of each light guide having at least one curvature defining a bend and forcing photons entering through its end face to join the front face of the second part after at least one internal reflection in this first part, N supports on each of which is installed a second part of a corresponding light guide; This lighting device is characterized by the fact that each support includes a rear part located in front of the wall of the rear part of the housing and including a second through hole located opposite a corresponding first through hole and allowing the passage of photons, coming from the end face and exiting at the level of a bend in the first part of the corresponding light guide, to an area of ​​the housing which is invisible from the outside of the latter.

[0010] Thanks to the invention, it becomes impossible for photons from a source to propagate to the front face of a second part of a light guide either directly without any reflection, or indirectly with at least one reflection at a very obtuse angle.

[0011] The lighting device according to the invention may include other features which may be taken separately or in combination, and in particular: The first part of each light guide may have two different curvatures defining two successive bends and forcing photons entering through its end face to reach the front face of the second part after at least two internal reflections in this first part; The lighting device according to the invention comprises a housing in which the N light guides are installed and comprising a rear part having a wall provided with N first through holes each located opposite the end face of a first part of a corresponding light guide and having an external face in front of which is installed the source which is associated with this light guide; it may comprise a support piece to which the N sources are coupled and installed on the external face of the wall of the rear part of the housing in front of the N first through holes;In the presence of the last sub-option, the support piece can be installed in a liquid and dust-tight manner on the external face of the rear wall of the housing; in the presence of the last sub-option, the support piece can function as a heat exchanger; The invention also proposes a vehicle, possibly of the automobile type, and comprising at least one lighting device of the type presented above.

[0012] For example, each lighting device can constitute a front or rear optical unit providing at least one photometric function for lighting or signaling. Brief description of the figures

[0013] Other features and advantages of the invention will become apparent upon examination of the detailed description below, and the accompanying drawings (obtained using CAD / CAM (“Computer-Aided Design / Computer-Aided Manufacturing”)), in which: [ Fig. 1] schematically illustrates, in a perspective view, part of an example of an embodiment of a lighting device according to the invention, [ Fig. 2 ] schematically illustrates, in a perspective view, the lighting system of the figure 1 without its support piece, [ Fig. 3 ] schematically illustrates, in a perspective view from the front, a rear part of the lighting device Figures 1 And 2 , And [ Fig. 4 ] schematically illustrates, in a cross-sectional view in a longitudinal and vertical plane at the level of a light guide, a part of the lighting system of the figure 1 . Detailed description of the invention

[0014] The invention aims in particular to propose a lighting device DE having at least one light guide GL comprising a first angled part P1, in particular so as to prevent the creation of a hot spot on an angled sub-part SPC of the second part P2 which extends this first part P1 and comprises a front face FV through which photons emerge participating in a photometric function.

[0015] For the purposes of this discussion, the following is considered, by way of non-limiting example, to be a DE lighting device intended for use in a motor vehicle, such as a car. However, the invention is not limited to this application. The DE lighting device can be a component that can be added to and used in numerous systems or that can be part of other equipment which is itself part of a system. Thus, the DE lighting device can be part of any vehicle (land, sea (or river), or air), any installation, including industrial installations, any device (or system), including consumer devices, and any building, for example.

[0016] Furthermore, in the following, the DE lighting device is considered, by way of non-limiting example, to constitute an optical unit of a motor vehicle providing at least one photometric function. However, this is not mandatory.

[0017] Furthermore, in the following, the DE lighting device is considered, by way of non-limiting example, to constitute a front light. However, it could also constitute a rear light or a front headlight (or projector) of a vehicle.

[0018] Finally, considering the preceding choices, the following will be considered, by way of non-limiting example, as assuming that the DE lighting device is intended to provide at least one photometric signaling function. For example, in the case of an application to a motor vehicle, this photometric signaling function could be a daytime running light (DRL) function. However, it could also be a position light function (possibly partially on the side) or a turn signal function.

[0019] It should be noted, however, that the invention is not limited to photometric signaling functions. Indeed, the lighting device DE, according to the invention, is a luminous device capable of providing at least one photometric signaling, lighting, or luminous effect (possibly decorative) function.

[0020] In the preceding and following text, the term "front" is defined with respect to the location from which the photons participating in the photometric function emerge, and the term "back" is defined with respect to the location opposite to that from which the photons participating in the photometric function emerge. Therefore, the front face of an element is oriented outwards, while the back face of that element is oriented inwards and opposite to the front face.

[0021] We have schematically illustrated on the figures 1 to 4 , part of an example of an embodiment of a DE lighting device according to the invention, here constituting a front optical unit of a vehicle.

[0022] As illustrated at least partially on the figures 1 to 4A lighting device DE, according to the invention, comprises N light guides GL and N photon sources S associated respectively with these N light guides GL, with N ≥ 1. It should be noted that in the example illustrated, but not limited to the... figures 1 to 3 The lighting device DE comprises three light guides GL and therefore also three photon sources S (i.e., N = 3). But a lighting device DE according to the invention can comprise any number N of light guides GL and photon sources S, provided that this number N is greater than or equal to one (1).

[0023] Each source S is arranged to generate photons when supplied with electric current.

[0024] For example, each photon source S can include at least one light-emitting diode (LED), or at least one laser diode, or a gas laser, or at least one bulb (possibly xenon). The choice of type for each photon source S may depend on the photometric function in which it participates. Also, for example, and as illustrated (but not limited to) on the figure 4 , each S photon source can be installed on an electronic CE board which can be a PCB type printed circuit board (“Printed Circuit Board”).

[0025] Each light guide GL comprises a first part P1 and a second part P2 that extend from each other. The first part P1 includes an end face FE that receives the photons generated by the associated source S. The second part P2 has a front face FV through which photons exit that originate from the first part P1 and have been reflected one or more times within it (P1).

[0026] As shown on the figures 3 and 4 , the first part P1 of each light guide GL has at least one curvature which defines a bend and forces photons entering through its end face FE to join the front face FV of the second part P2 after at least one internal reflection in this first part P1.

[0027] On the figure 4 The "paths" of photons are represented by dashed lines.

[0028] It will be understood that, due to the angled shape of each first part P1, it becomes impossible for photons from the associated source S to propagate from the end face FE to the front face FV of the second part P2 either directly without any reflection, or indirectly with at least one reflection at a very obtuse angle. Therefore, the photons reach the front face FV of the second part P2 at angles of incidence that favor either their reflection towards downstream sub-parts, from which they will emerge in a predefined general direction dg (adapted to the photometric function to be performed), or their exit in this predefined general direction dg. In particular, if each second part P2 includes an angled sub-part SPC, as illustrated in the figures 3 and 4There is no longer a risk of creating a hot spot at the level of this SPC angled sub-section since photons can no longer propagate significantly along its axis (SPC), and therefore the front face FV of each second P2 section, visible from the outside, appears to be homogeneously illuminated. It should be noted that this particular arrangement advantageously eliminates the need for local installation of a mask (or cover) against each SPC angled sub-section or for defining (or extending) black areas intended to mask at least part of the SPC angled sub-sections.

[0029] It should be noted, as appears but not limited to the figure 3The first part P1 of each light guide GL can have two different curvatures that define two successive bends and force photons entering through its end face FE to reach the front face FV of the second part P2 after at least two internal reflections in this first part P1. This further reduces the probability of a photon exiting at a bent sub-part SPC of a second part P2.

[0030] In the example shown on the figure 3Each first part P1 comprises a first angled sub-part including the end face FE and extending downwards and from left to right, and a second angled sub-part extending from the first angled sub-part upwards to the beginning of the second part P2. This results from the fact that the sources S are placed above the end faces FE, which are oriented upwards. However, other arrangements corresponding to different orientations of the sources S and the end faces FE, and therefore also of the bends in the first parts P1, can be considered. For example, the end faces FE could be oriented downwards, in which case the sources S are placed below the end faces FE; or to the left, in which case the sources S are placed to the left of the end faces FE; or to the right, in which case the sources S are placed to the right of the end faces FE.

[0031] It should also be noted, as illustrated but not limited to the following, figures 1 to 4 , that the lighting device DE may include a housing BB in which the N light guides GL are installed. Note that in the example illustrated, but not limited to the figure 4 The N light guides GL are housed in an internal housing LI which is defined by the housing BB and a glass GD placed in front of the second parts P2 of the N light guides GL and forming part of the lighting device DE. But in an embodiment in which the lighting device DE is part of an optical block, the housing BB is part of the latter.

[0032] As illustrated on the figures 2 to 4 The BB housing comprises a rear portion PRB with a PP wall that has N first through holes T1, each located opposite the end face FE of a first portion P1 of a corresponding light guide GL. Furthermore, and as illustrated in the figure 4This housing BB has an external face opposite the internal housing LI, in front of which each light source S, associated with one of the N light guides GL, is installed. In other words, the N light sources S are installed outside the housing BB (and therefore outside the internal housing LI), making them invisible to a person standing in front of the mirror GD and eliminating the need for a mask inside the internal housing LI to conceal them, thus reducing the space required within LI. Furthermore, this prevents the accumulation of heat generated during operation by the N light sources (and their associated electronics) within the internal housing LI.

[0033] For example, and as illustrated but not limited to the Figures 1 And 4The lighting device DE may include a support piece PS to which the N light sources S are coupled. This support piece PS is installed on the outer face of the PP wall of the rear part PRB of the housing BB, in front of the first N through holes T1. This installation can be achieved by clipping and / or screwing, for example. When the N light sources are installed on an electronic board CE, the latter (CE) is fixedly attached to the inner face of the support piece PS, which is oriented towards the PP wall of the rear part PRB (and therefore towards the first N through holes T1), as illustrated, but not limited to, in the figure 4 .

[0034] It should be noted that this PS support piece can be installed in a liquid- and dust-tight manner on the outer face of the PP wall of the rear PRB section of the BB housing. This protects the N power sources (and the associated electronics on the optional CE electronic board), and also prevents liquid and dust from entering the internal LI housing through the first N through holes T1. For example, this seal can be achieved by means of small, closed peripheral walls (or ribs) PE1 and PE2, respectively, on the inner face of the PS support piece and the outer face of the PP wall of the rear PRB section of the BB housing, one surrounding the other, possibly with an interposed gasket.

[0035] It should also be noted that the PS support piece can possibly provide a heat exchanger (or radiator) function, in order to evacuate through its external face (opposite to its internal face) the calories generated during operation by the N sources (and the associated electronics on the possible CE electronic board).

[0036] It should also be noted, as illustrated but not limited to the following, figures 1 to 4 The lighting device DE can include N supports SG, on each of which a second part P2 of a corresponding light guide GL is installed. This allows each light guide GL to be precisely positioned within the internal housing LI.

[0037] Each SG support can be a part that is added to the inner face of the rear PRB part of the BB housing, for example by gluing, clipping or screwing, or it can be an integral part of the rear PRB part of the BB housing, especially when the latter (PRB) is made by molding.

[0038] Furthermore, each SG support may, optionally and as illustrated but not limited to, include a bearing face on which the rear face FR of the second part P2 of the corresponding light guide GL is placed, and which has a shape homologous to that of this second part P2. This allows for even more precise positioning of the second part P2 of each light guide GL within the internal housing LI, and also allows for the reflection of photons exiting through its rear face FR back into the second part P2 concerned.

[0039] It should also be noted, as illustrated but not limited to the following, on the figure 4Each support SG may include a rear portion located in front of the PP wall of the rear PRB portion of the BB housing and comprising a second through-hole T2 located opposite a corresponding first through-hole T1. Each second through-hole T2 advantageously allows the passage of photons, originating from the end face FE and exiting at a bend in the first portion P1 of the corresponding light guide GL, to a region Z of the BB housing that is invisible from the outside of the latter (BB), in order to trap them. This prevents unwanted reflections of these photons, prematurely exiting a first portion P1, off at least one wall of the rear PRB portion of the BB housing, which could otherwise reflect them back towards the glass GD, giving them an exit direction different from the predefined general direction dg.

[0040] It should also be noted that in the illustrated example, the N light guides GL are elongated with a circular cross-section. However, they could have cross-sections with other geometric shapes (for example, elliptical).

[0041] It should also be noted that GL light guides can be manufactured using a plastic or synthetic material during a molding process. For example, polycarbonate (or PC) or polymethyl methacrylate (or PMMA) can be used.

Claims

1. Lighting device (DE) for a vehicle comprising: - N light guides each comprising a first part (P 1) receiving, via an end face (FE), photons generated by an associated source (S) and a second part (P 2) comprising a front face (FV) through which photons from said first part (P 1) exit, with N ≧1, said first part (P 1) of each light guide (GL) having at least one curvature defining a bend and forcing the photons penetrating via its end face (FE) to join said front face (FV) of the second part (P 2) after at least one internal reflection in this first part (P 1), - a housing (BB) in which said N light guides (GL) are installed and comprising a rear part (PRB) comprising a wall (PP) provided with N first through holes (T 1) each located facing said end face (FE) of said first part (P 1) of a corresponding light guide (GL) and having an outer face in front of which is installed the source (S) associated with this light guide (GL), - N supports (SG) on each of which is installed a second part (P2) of a corresponding light guide (GL), - wherein each support comprises a rear part located in front of said wall of said rear part of said housing and comprising a second through hole facing a corresponding first through hole and allowing the passage of photons from said end face and emerging at the level of an elbow of said first part of the corresponding light guide towards a zone of said housing invisible from the outside of the latter.

2. Lighting device according to claim 1, wherein said first part (P 1) of each light guide (GL) has two different curvatures defining two successive bends and forcing the photons penetrating via its end face (FE) to join said front face (FV) of the second part (P 2) after at least two internal reflections in said first part (P 1).

3. Lighting device according to claim 1, further comprising a support component to which said N sources are coupled and installed on said outer face of said wall of the rear portion of said housing in front of said N first through holes.

4. Lighting device according to claim 3, wherein said support component is installed in a liquid and dust tight manner on said outer face of said wall of said rear portion of said housing.

5. Lighting device according to claim 3 or 4, wherein said support component performs a heat exchanger function.

6. Vehicle, characterised in that it comprises at least one lighting device (DE) according to one of claims 1 to 5.

7. Vehicle according to claim 6, wherein each lighting device constitutes a front or rear optical unit providing at least one photometric lighting or signalling function.