Lighting device for a motor vehicle

Abstract

A lighting device (1) for a motor vehicle (3), the lighting device (1) comprising: - a support (11), - a plurality of light sources (16) fastened to the support (11), - a grid (13) comprising a plurality of cells (19), each cell being positioned facing a light source, - a scattering film (15) covering the grid, the grid extending between the support and the scattering film, the scattering film comprising a plurality of masking elements (20), each masking element being configured to block light rays (Ri) coming from a light source associated with a first cell and that are liable to reach a second cell adjacent to the first cell by reflection against an outer face (152) of the scattering film.

Description

[0001] DESCRIPTION

[0002] TITLE: Lighting device for motor vehicle

[0003] Technical field of the invention

[0004] The technical context of the present invention is that of signaling devices for motor vehicles, in order to be able to signal the presence of a motor vehicle or transmit certain messages to other motor vehicles. More particularly, the invention relates to a lighting device for a motor vehicle.

[0005] State of the prior art

[0006] In the prior art, lighting devices for motor vehicles are known, comprising light sources configured to emit light rays, each light source being optically coupled to a light guide so that at least a portion of the light rays generated by each light source is injected into the associated light guide and forms, at an output face, a matrix network of cells. Each cell is thus controlled so as to be able to generate "light pixels" making it possible to create numerous lighting functions on motor vehicles. Such lighting functions make it possible in particular to indicate to a neighboring motor vehicle one or more pieces of information relating, for example, to a state of the motor vehicle on which the lighting device is mounted, or to a state of traffic that the neighboring motor vehicle will soon experience.For example, such light devices can indicate information relating to the state of charge of an electric traction battery, a breakdown, a speed and / or a future trajectory of the motor vehicle.

[0007] A known disadvantage of such light devices concerns the optical coupling between two adjacent cells: such optical coupling leads to light rays from a first cell propagating into or at a second cell directly adjacent to the first cell. Such optical coupling is not desired because it deteriorates the visibility of the light information to be displayed by known light devices by modifying the light intensity of an adjacent cell, in particular by increasing its light intensity or by giving the impression that this adjacent cell is lit when it should be off.

[0008] In a known manner, the optical coupling between two adjacent cells is reduced by increasing the interval between said two adjacent cells. This solution, however, leads to a degradation of the spatial density of the cells on known light devices.

[0009] Presentation of the invention

[0010] The aim of the invention is to provide a lighting device which overcomes the above drawbacks and improves the lighting devices known from the prior art.

[0011] More specifically, an object of the invention is a light device making it possible to improve the optical isolation between two adjacent cells by reducing optical coupling.

[0012] Summary of the invention

[0013] The invention relates to a lighting device for a motor vehicle, the lighting device comprising:

[0014] - a support,

[0015] - a plurality of light sources fixed to the support,

[0016] - a grid comprising a plurality of cells, each cell being positioned opposite a light source,

[0017] - a diffusing film covering the grid, the grid extending between the support and the diffusing film, the diffusing film comprising a plurality of masking elements, each masking element being configured to block light rays from a light source associated with a first cell and likely to reach a second cell adjacent to the first cell, by reflection against an external face of the diffusing film. According to one embodiment, at least some masking elements are formed by depositing an opaque ink on an external face or on an internal face of the diffusing film. The deposition of the ink on the diffusing film allows more precise formation of the masking elements.

[0018] According to one embodiment, the grid is formed from a material having a high modulus of elasticity so as to give it flexibility or suppleness allowing it to be deformed during mounting on the lighting device. Thus, the grid has the ability to conform to the different shapes that the support of the lighting device could have. In addition, this facilitates the installation of the grid within the lighting device.

[0019] According to one embodiment, the ratio of the printed width of the masking elements to the thickness of the diffusing film is at least 2.75. It is found that such a ratio allows for better blocking efficiency of the parasitic rays of the masking elements.

[0020] According to one embodiment, at least certain masking elements are formed by local cutting of the diffusing film, in the thickness of the diffusing film.

[0021] According to one embodiment, the diffusing film comprises a thickness less than or equal to 1 mm.

[0022] According to one embodiment, the diffusing film comprises polycarbonate, or polyethylene terephthalate, or polymethyl methacrylate.

[0023] According to one embodiment, the diffusing film is in direct contact with the grid.

[0024] According to one embodiment, the grid comprises a plurality of partitions which extend between the diffusing film and the support, the partitions extending projecting from the support and delimiting the cells.

[0025] According to one embodiment, the masking elements are positioned opposite said partitions. According to one embodiment, the cells have a polygonal shape comprising edges connected by vertices, the masking elements extending directly above edges of the polygonal shapes but not directly above vertices of the polygonal shapes.

[0026] According to one embodiment, the grid is formed from a material opaque to the light rays generated by the light sources.

[0027] Presentation of figures

[0028] These objects, characteristics and advantages of the present invention will be explained in detail in the following description of several particular embodiments made without limitation in relation to the attached figures among which:

[0029] Figure 1 illustrates a schematic sectional view of a first exemplary embodiment of a light device according to the invention.

[0030] Figure 2 is a simplified schematic and sectional view of the light device of Figure 1.

[0031] Figure 3 is a schematic front view of the light device of Figure 1 when a portion of the light sources of the light device are on and the other portion of the cells are off.

[0032] Figure 4 illustrates a cutaway perspective view of a second exemplary embodiment of the lighting device according to the invention.

[0033] Figure 5 is a schematic front view of a diffusing film of the light device of Figure 4.

[0034] Figure 6 is a schematic and sectional view of a third example of a lighting device according to the invention.

[0035] Figure 7 illustrates a motor vehicle comprising a lighting device according to the invention. Figure 8 is a schematic and sectional view of a lighting device according to the state of the art.

[0036] Figure 9 is a schematic front view of the light device according to the state of the art when part of the light sources of the light device is on and the other part of the cells is off.

[0037] Detailed description

[0038] Figures 1 and 2 illustrate a light device 1 according to a first embodiment of the invention. The light device 1 is configured to display one or more pictograms in a pixelated manner in order to display and transmit information to an observer located at a distance from the light device 1.

[0039] The light device 1 comprises a support 11, a plurality of light sources 16, a diffusing film 15, and a grid 13 interposed between the support 11 and the diffusing film 15.

[0040] The light sources 16 are configured to generate light rays. The light sources 16 may be of the light-emitting diode type, each light source comprising one or more light-emitting diodes. By light-emitting diode, we mean any type of light-emitting diode, such as for example LEDs - English acronym meaning "Light Emitting Diode" and translated as Electroluminescent Diode, OLEDs - English acronym meaning "organic LED" and translated as Organic Light-Emitting Diode, AMOLEDs - English acronym meaning "Active-Matrix-Organic LED" and translated as Active Matrix with Organic Light-Emitting Diodes, or FOLEDs - English acronym meaning "Flexible OLED" and translated as Flexible Organic Light-Emitting Diode.Advantageously, the light sources are selectively controlled by a control unit which regulates a power supply current for each of said light sources in order to control their emission of light rays. It is thus possible to selectively control the light sources in order to configure them in any configuration between an off configuration and a maximum illumination configuration.

[0041] The light sources 16 are integral with the support 11. The support 11 forms a common mechanical support for all the light sources 16 of the lighting device. By way of non-limiting example, the support 11 may take the form of a plastic plate, forming for example a printed circuit, or a printed film. The support 11 is also configured to allow the routing of electrical signals making it possible to selectively control and supply the electrical energy necessary for the operation of the light sources 16. In addition, the support 11 may be of variable geometry. The support may be flat or curved. Generally speaking, the support 11 is an electronic card electrically connected to the light sources 16. The light sources 16 may be fixed integrally to the support 11, for example by welding.The lighting device 1 further comprises an electrical connection interface 18 making it possible to supply electrical energy to the light sources 16 via electrical connectors 181.

[0042] In all of the figures, a longitudinal axis X, a transverse axis Y and a vertical axis Z are defined relative to the light device 1. More particularly, the transverse axis Y and the longitudinal axis X together define a plane in which the light sources 16 are distributed. The vertical axis Z is understood to be taken along a general direction of propagation of the light rays generated by the light sources 16. In general, the vertical axis Z is substantially perpendicular to the support 11.

[0043] The grid 13 comprises a plurality of adjacent cells 19, each cell facing a light source 16. Each cell 19 is separate from a directly adjacent cell 19. The grid 13 forms an openwork mask 12 at a distal end of the light sources 16. Each light source 16 is thus associated with one and only one cell 19. The cells thus make it possible to isolate the different light sources in order to produce a pixelated light display. At one end of the grid 13 distal to the support 11, the openwork mask 12 defines a set of crosspieces which separate two adjacent cells 19, so as to form a two-dimensional network of cells 19 whose local and selective illumination state will make it possible to generate the light information to be displayed on the light device 1.

[0044] In the embodiments shown in the figures, the openwork mask 12 and the grid 13 are made of one material, so as to form a single, single-piece assembly. The grid 13 is preferably formed from a material comprising silicone or elastomer. The grid 13 is preferably obtained by molding.

[0045] The lighting device also comprises a closing glass 14 located opposite the cells 19. The grid 13 and the diffusing film 15 are held in engagement between the closing glass 14 and the support 11. Advantageously, the grid 13 can be flexible, so as to be able to be deformed when it is mounted between the support 11 and the closing glass 14. The grid 13 can therefore be formed from a material whose modulus of elasticity is high, so as to allow deformation of the grid 13 when the latter is mounted on the lighting device 1. The flexibility of the grid 13 makes it possible to adapt to the curve of the closing glass 14.

[0046] When mounting the lighting device 1, the grid 13 may first be affixed to the support 11 in order to isolate each light source 16 in a single cell 19 formed by the grid 13. The diffusing film 15 may then be affixed to the grid. The grid 13 and the diffusing film 15 may then be compressed between the support 11 and the closing glass 14 - directly or indirectly - so as to keep said grid 13 engaged and sandwiched against the support 11 and said diffusing film 15 against the grid 13. This advantageous configuration thus makes it possible to prevent the grid 13 and the diffusing film 15 from moving during use of the lighting device 1. Alternatively, the grid 13 and the diffusing film 15 could be held against the support by any securing means.

[0047] The closing glass 14 is integral with the support 11 and keeps the grid 13 engaged against the support 11. The closing glass 14 can in particular be fixed integrally and directly to the support 11. The closing glass 14 has an outlet face 141 and side faces 142 which collaborate with the support 11 in order to together form a housing 10 for the grid 13, the light sources 16 and the diffusing film 15.

[0048] As mentioned above, the grid 13 comprises a set of crosspieces which delimit directly adjacent cells 19. This set of crosspieces thus forms the openwork mask 12 of the grid 13, visible from the outside. Between the openwork mask 12 and the support 11, the grid 13 extends these crosspieces through a set of partitions 131 which extend projecting from the openwork mask 12 and in the direction of said support 11. Each partition 131 thus forms an opaque wall for the light rays generated by the light sources, each partition 131 laterally and longitudinally delimiting a cell 19.

[0049] The partitions 131 of the grid 13 can take any shape and any dimension. However, for reasons of homogeneity, the dimensions of a cell 19 taken in a plane formed by the longitudinal axis X and the transverse axis Y are preferably constant for the entire lighting device 1. Consequently, a geometry of the cells 19 taken in the plane formed by the longitudinal axis X and the transverse axis Y is constant for the entire lighting device 1.

[0050] In the various illustrated embodiments, the cells 19 delimited by the grid 13 have a polygonal shape, and more particularly rectangular or even square. Alternatively, the shape of these cells could also be triangular, and more generally adopt any geometric shape allowing the plane to be tiling. The number of cells 19 can be any. Preferably, the light module 1 comprises at least one square comprising 3x3 cells, more preferably at least 5x5 cells.

[0051] Along the vertical axis Z, the partitions 131 delimiting the cells 19 can be rectilinear or curved, depending on the desired effects. Furthermore, in the plane formed by the vertical axis Z and the longitudinal axis X or the transverse axis Y, the partitions 131 of two adjacent cells 19 have a “V” shape, one point of which is located on the side of the closing glass 14, at one end of the grid 13 distal to the light sources 16 and the support 11. Two adjacent partitions 131 delimiting two adjacent cells 19 are connected to each other at the end of the grid 13 distal to the support 11. The partitions 131 forming the grids can have a constant thickness.

[0052] In order to promote the support of the grid 13 against the support 11, the grid 13 may comprise a rim 132 located at a lower end of the partitions 131 located near said support 11. The rim 132 thus forms a support zone for the grid 13 on the support 11. More particularly, each partition 131 delimiting a cell 19 comprises such a rim 132. The rim 132 thus forms a protrusion which projects from the partition 131, relative to the transverse axis Y or to the longitudinal axis X. Advantageously, the rim 132 extends in the direction of the cell 19, so as to form a peripheral frame for the light source 16 associated with said cell 19.

[0053] Furthermore, the light source 16 is located above each rim 132 of the associated cell 19, relative to the vertical axis Z. In other words, the rims 132 defining the support area of ​​the grid 13 against the support 11 form a peripheral frame for each light source 16 and making it possible to reduce or even prevent optical coupling between two adjacent cells 19, at the level of the support 11. Indeed, as the light source 16 is now located beyond the rim 132 relative to the support 11, then the light rays generated by an emission face 161 of the light source 16 necessarily extend in the direction of the exit face 141 of the closing glass 14, and not in the direction of the support 11.

[0054] The diffusing film 15 makes it possible to diffuse the light rays generated by each light source 16 into the illuminated cells 19 of the lighting device 1. The diffusing film 15 thus makes it possible to deflect the incident light rays in a plurality of different directions, thus improving the visual rendering of the lighting device 1 during its use and also making it possible to reduce an apparent distance between two adjacent cells 19. Preferably, there is zero clearance between the mask 13 and the diffusing film 15. Similarly, there is preferably zero clearance between the diffusing film 15 and the exit face 141. The diffusing film 15 is mounted to bear against the end of the distal grid 13 of the support 11, at the level of the openwork mask 12. The diffusing film 15 is then held in abutment against the grid 13 by means of the closing glass 14.

[0055] The diffusing film 15 is a thin membrane extending against one end of the distal grid 13 of the support 11. The diffusing film may for example have a thickness of between 0.1 mm and 1 mm inclusive. The diffusing film 15 may be made of a transparent or translucent material. It may in particular comprise polycarbonate (PC), or polyethylene terephthalate (PET) or polymethyl methacrylate (PMMA). The diffusing film comprises an inner face 151 facing the light sources 16 and an outer face 152, opposite the inner face 151. The inner face 151 bears directly against the "V"-shaped tips of the grid 13. The outer face 152 is in direct contact with the outlet face 141 of the closing glass 14.

[0056] In order to diffuse the light produced by the light sources 16, the diffusing film 15 advantageously comprises a surface structuring, that is to say a set of micro-reliefs intended to deflect light rays. This surface structuring can be formed on the internal face 151 and / or on the external face 152 of the diffusing film 15.

[0057] According to the invention, the diffusing film 15 further comprises a set of masking elements 20. Each masking element 20 is configured to block unwanted light rays from a first light source associated with a first cell, these unwanted light rays being capable of reaching a second cell adjacent to the first cell, by reflection against the external face 152 of the diffusing film. The masking elements 20 are integral with the diffusing film 15.

[0058] Such unwanted light rays Ri are shown in Figure 8 representing a light module according to the state of the art. The unwanted light rays can in particular reach the external face 152 of the diffusing film after reflection against the partitions 131 of the grid 13, or even directly without reflection against the partitions 131 of the grid 13. By reflection against the external face 152 of the diffusing film, these unwanted light rays at least partially illuminate cells 19 in which the light source is off, and consequently alter the contrast of the light pattern produced by the light module. Figure 9 illustrates the visual rendering of a light module according to the state of the art. According to the example shown, the light module comprises 9x11 cells and only a central rectangle of 4x6 cells comprises light sources 16 lit. However, it can be seen that the cells adjacent to the central rectangle are partially illuminated.As a note, the thickness of the diffusing film shown in FIG. 2 is exaggerated to visualize the phenomenon of reflection of unwanted light rays on the external face 152. In reality, the thickness of the diffusing film 15 is much smaller so that reflections of light rays in the thickness of the diffusing film are difficult to highlight.

[0059] The masking elements 20 are therefore advantageously positioned opposite the partitions 131. According to the embodiment shown in FIGS. 1 and 2, each masking element 20 is formed by depositing an opaque ink, for example an opaque paint or an opaque varnish, applied locally on the diffusing film. The opaque ink may be black in color, or at least dark in color. The opaque ink extends directly above the boundary lines between adjacent cells 19. The opaque ink thus substantially reproduces the shape of the openwork mask 12.

[0060] The opaque ink can be deposited on the diffusing film 15 by different techniques including screen printing or digital printing.

[0061] The opaque ink can be applied either to the inner face 151 or to the outer face 152 of the diffusing filter 15. According to the embodiment illustrated in FIGS. 1 and 2, the opaque ink is applied to the outer face 152 of the diffusing filter 15.

[0062] The opaque ink may be applied in a grid pattern, i.e., along a set of intersecting lines. These lines then follow the outline of each cell 19. Alternatively, the opaque ink may also be applied along a set of non-joining segments. In this case, the diffusing film would not include opaque ink at the vertices of the polygonal shapes of each cell (i.e., at the four corners of the square shapes in this case). This is not a problem since the unwanted light rays pass from one cell to another by passing through the edges of the polygonal shapes and not through their vertices.

[0063] Figure 2 shows the unwanted light rays Ri that may reach an adjacent cell. The opaque ink is positioned so that the unwanted light rays Ri necessarily reach a layer of opaque ink during their path. The unwanted light rays Ri are then absorbed by the opaque ink and not reflected towards an adjacent cell. Thus, the cells whose light source 16 is switched off do not receive any light rays. As illustrated in Figure 3, the display contrast obtained with such a light device is optimal.

[0064] Furthermore, the ratio of the printed width of the masking elements 20 to the thickness of the diffusing film 15 may be at least 2.75. This determined ratio allows for better masking to prevent unwanted light rays Ri from passing from one cell to an adjacent cell. The thickness of the diffusing film 15 is smaller than the width of the printed masking elements.

[0065] The thickness of the diffusing film, referenced “e” in figure 2, can be between 0.1 mm and 1 mm.

[0066] The printed width of the masking elements 20, referenced “L” in Figure 2, can be between 0.8mm and 1.2mm. The printed width is always greater than the thickness of the film.

[0067] Figure 4 illustrates an alternative embodiment in which the masking elements 20 are formed by local cutting of the diffusing film, in the thickness of the diffusing film. The cutouts are therefore slits of non-zero width. The two opposite edges of the slits are not in contact with each other. The cutouts thus form an interruption in the propagation medium of the light waves. The cutouts can be free, that is to say that no material fills the cutouts. The simple variation in refractive index between the material of the diffusing film and the ambient air is sufficient to block the propagation of most of the unwanted light rays. This embodiment is particularly simple to produce. Alternatively, the cutouts could be filled with an opaque material in order to further increase the blocking of the unwanted light rays.

[0068] The cutouts can for example be made by laser. Advantageously, each cutout extends along an edge of the polygonal shape of a cell. As illustrated in Figure 5, the different cutouts are not joined in order to maintain a diffusing film in one piece. The diffusing film 15 thus comprises a set of holding points 21 formed at the ends of each cutout. The holding points 21 are positioned directly above the vertices of the polygonal shapes of each cell (in particular directly above the corners of the square shapes of each cell in this case). As explained previously, this is not a problem since the unwanted light rays pass from one cell to another by passing through the edges of the polygonal shapes and not through their vertices.

[0069] Figure 6 illustrates an alternative embodiment of the invention in which the lighting device 1 further comprises a housing 17 comprising a bottom wall 171 and side walls 172 which together delimit a housing 10 housing the grid 13, the light sources 16 and the diffusing film 15. The diffusing film 15 is fixed integrally and directly to the housing 17, for example by screwing into the side walls 172 of the housing 17. According to this alternative embodiment, the diffusing film 15 acts as a closing glass and forms the exit face 141 of the lighting device 1. The masking elements 20 can be produced both by depositing ink and by locally cutting the diffusing film in the thickness of the diffusing film, as explained previously.

[0070] With reference to Figure 7, a motor vehicle 3 is described comprising a signaling device 2 comprising a light device 1 as described previously. The signaling device 2 may be arranged at the rear of the vehicle as shown in Figure 7, or on the contrary be arranged at the front of the vehicle. The signaling device 2 may be of the type of a rear direction indicator or a rear brake light or a night-time rear position light or a rear fog light. Alternatively, the signaling device 2 could also be a position light, a daytime running light, or even a flashing light.

[0071] In summary, the invention relates to a lighting device 1 comprising a grid 13 delimiting a plurality of cells 19 organized according to a two-dimensional network. Each cell 19 is associated with a light source 16 that can be selectively controlled to be illuminated or extinguished, so as to be able to generate a light pictogram on the two-dimensional network. When a light source 16 is lit, it emits light rays in different directions. First light rays emerge from the lighting device by passing through the portion of the output face 141 facing the light source, without undergoing any reflection. Second light rays emerge from the lighting device by passing through the portion of the output face 141 facing the light source after having undergone one or more reflections against the partitions 131 of a cell associated with the light source from which the second light rays are emitted.Finally, third light rays form undesirable light rays and have an incidence such that they could be reflected by the external surface 152 of the diffusing film 15 and penetrate into a neighboring cell before being reflected towards the outside of the light module by passing through a portion of the exit face opposite this neighboring cell. However, these third light rays are advantageously blocked by a masking element 20. In practice, these third light rays are therefore stopped before being emitted outside the light module. No light ray from a neighboring cell is therefore emitted. The optical isolation between adjacent cells is thus optimized.

Claims

CLAIMS 1. Lighting device (1) for a motor vehicle (3), the lighting device (1) comprising: - a support (1 1 ), - a plurality of light sources (16) fixed to the support (11), - a grid (13) comprising a plurality of cells (19), each cell being positioned opposite a light source, - a diffusing film (15) covering the grid, the grid extending between the support and the diffusing film, the diffusing film comprising a plurality of masking elements (20), each masking element being configured to block light rays (Ri) coming from a light source associated with a first cell and likely to reach a second cell adjacent to the first cell, by reflection against an external face (152) of the diffusing film.

2. Luminous device (1) according to the preceding claim, characterized in that at least certain masking elements (20) are formed by depositing an opaque ink on an external face or on an internal face of the diffusing film (15).

3. Lighting device (1) according to claim 1, characterized in that the grid (13) is formed from a material whose modulus of elasticity is high so as to allow deformation of the grid (13) when the latter is mounted on the lighting device (1).

4. Luminous device (1) according to one of the preceding claims, characterized in that the ratio of the printed width (L) of the masking elements (20) to the thickness (e) of the diffusing film (15) is at least 2.

75.

5. Luminous device (1) according to one of the preceding claims, characterized in that at least certain masking elements (20) are formed by local cutting of the diffusing film, in the thickness of the diffusing film.

6. Luminous device according to one of the preceding claims, characterized in that the diffusing film (15) has a thickness less than or equal to 1 mm.

7. Luminous device according to one of the preceding claims, characterized in that the diffusing film (15) comprises polycarbonate, or polyethylene terephthalate, or polymethyl methacrylate (PMMA).

8. Luminous device (1) according to one of the preceding claims, characterized in that the diffusing film (15) is in direct contact against the grid (13).

9. Luminous device (1) according to one of the preceding claims, in which the grid (13) comprises a plurality of partitions (131) which extend between the diffusing film (15) and the support (11), the partitions (131) extending in projection from the support (11) and delimiting the cells (19).

10. Luminous device (1) according to the preceding claim, characterized in that the masking elements (20) are positioned opposite said partitions (131). 1 1. Lighting device (1) according to one of the preceding claims, characterized in that the cells have a polygonal shape comprising edges connected by vertices, the masking elements (20) extending directly above the edges of the polygonal shapes but not directly above the vertices of the polygonal shapes.

12. A light device (1) according to any one of the preceding claims, wherein the grid (13) is formed from a material opaque to the light rays generated by the light sources (16).

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