Lighting device for a motor vehicle

Abstract

The invention relates to a lighting device (1) for a motor vehicle, characterised in that it comprises: - a first curved printed circuit board (5) comprising a first set of light-emitting diodes (51), - a second curved printed circuit board (6) comprising a second set of light-emitting diodes (61), the second printed circuit board being adjacent to the first printed circuit board and offset with respect to the first printed circuit board, - a grating (3) comprising a plurality of cells (31), each cell being positioned opposite at least one light-emitting diode of the first set of light-emitting diodes or of the second set of light-emitting diodes.

Description

Lighting device for a motor vehicle Technical field of the invention

[0001] The invention relates to a lighting device for a motor vehicle, in particular a signaling device intended to indicate the presence of a motor vehicle and / or to transmit certain messages to other motor vehicles. The invention also relates to a method for manufacturing such a lighting device. Prior art

[0002] We know of lighting systems for motor vehicles comprising a set of light sources, each light source optically coupled to a cell in a matrix array. Each light source is individually controlled to generate "light pixels," thus enabling numerous lighting functions. These lighting functions can, in particular, signal the presence of the vehicle and also transmit one or more pieces of information to a person in the vehicle's vicinity.

[0003] A known drawback of such lighting devices concerns optical coupling between two adjacent cells: such optical coupling causes light rays from one cell to propagate into a second cell directly adjacent to the first. This optical coupling is undesirable because it degrades the visibility of the light information displayed by the lighting device by altering the light intensity of an adjacent cell, notably by increasing its intensity or giving the impression that the adjacent cell is lit when it should be off. A known method for reducing optical coupling between two adjacent cells is to integrate a grid into the lighting device, the walls of which optically isolate the different cells.

[0004] Furthermore, the individual light cells of such a lighting system are generally light-emitting diodes (LEDs) arranged on a single printed circuit board. The LEDs are thus arranged on the same plane, which constitutes a significant geometric constraint for such lighting systems. The lighting systems known from the prior art are therefore relatively bulky and difficult to integrate into the curved profile of a motor vehicle. Moreover, these lighting systems are generally best seen from a single direction, which corresponds to the direction perpendicular to the plane in which the printed circuit board extends. Presentation of the invention

[0005] The object of the invention is to provide a lighting device that remedies the above disadvantages and improves upon known lighting devices of the prior art.

[0006] More specifically, a first object of the invention is a compact lighting device, suitable for harmonious integration into a motor vehicle, and clearly visible when viewed from different directions.

[0007] The invention relates to a lighting device for a motor vehicle, the lighting device comprising: - a first curved printed circuit board comprising a first set of light-emitting diodes, - at least a second curved printed circuit board comprising a second set of light-emitting diodes, the second printed circuit board being adjacent to the first printed circuit board and offset from the first printed circuit board, - a grid comprising a plurality of cells, each cell being positioned with respect to at least one light-emitting diode of the first set of light-emitting diodes or of the second set of light-emitting diodes, the grid comprising an input face extending opposite the first printed circuit board and opposite the second printed circuit board, the grid comprising an output face curved along at least two non-parallel axes.

[0008] Each cell of the grid can include a lighting coefficient defined by the ratio of the lighting area of ​​the cell in question to the depth of the cell in question, all cells of the grid including a substantially equal lighting coefficient.

[0009] The grid can be made of a flexible material such as silicone or an elastomer, in particular EPDM.

[0010] The first printed circuit board can be bent along a first curved line, and the second printed circuit board can be bent along a second curved line, the first curved line being not parallel to the second curved line.

[0011] The lighting device may further include at least one third curved printed circuit board comprising a third set of light-emitting diodes, the third printed circuit board being adjacent to the first printed circuit board and the second printed circuit board, each grid cell being positioned opposite at least one light-emitting diode from the first set of light-emitting diodes or the second set of light-emitting diodes or the third set of light-emitting diodes, the input face of the grid also extending opposite the third printed circuit board.

[0012] The lighting device may further include: - a support, intended to be fixed to a motor vehicle, the first printed circuit board and the second printed circuit board being fixed to the support, and - a transparent or translucent closing glass covering the grid, the grid being trapped between the support and the glass.

[0013] The grid can be made of a material that is more flexible than the support and more flexible than the ice, with the grid being compressed between the ice and the support.

[0014] The support may include: - a first curved surface, the first printed circuit board extending against the first surface and being fixed to the first surface with two fixing means arranged at two opposite ends of the first printed circuit board, and - a second curved surface, the second printed circuit board extending against the second surface and being fixed to the second surface with two fixing means arranged at two opposite ends of the second printed circuit board.

[0015] The support may include a first set of positioning pins cooperating with holes formed in the first printed circuit board and / or the second printed circuit board. The grid may include a second set of positioning pins cooperating with holes formed in the first printed circuit board and / or the second printed circuit board and / or in the support.

[0016] The first printed circuit board may include a first electrical connector, the second printed circuit board may include a second electrical connector, and the support may include an opening through which the first electrical connector and the second electrical connector are arranged.

[0017] The invention also relates to a method of manufacturing a lighting device as defined above, the method comprising: - supplying the first printed circuit board, the second printed circuit board, the grid, the support and the glass, then - placing the first printed circuit board and the second printed circuit board on the support, then - placing the grid against the support, the first printed circuit board and the second printed circuit board, then - placing the glass against the grid. Presentation of the figures

[0018] These objects, features and advantages of the present invention will be described in detail in the following description of a particular embodiment, given by way of non-limiting example, with reference to the accompanying figures, among which:

[0019] This is a perspective view of a lighting device according to an embodiment of the invention.

[0020] This is a perspective view of the lighting device, with a closing glass panel for the lighting device having been removed.

[0021] This is a perspective view of a grid of the lighting system.

[0022] This is a perspective view of the lighting device, with the closing glass and the grid of the lighting device having been removed.

[0023] This is a detailed view of a cell in the grid of the lighting device according to one embodiment variant.

[0024] This is a perspective view of a support for the lighting device.

[0025] This is a front view of the lighting device, the closing glass of the lighting device having been removed.

[0026] This is a cross-sectional view in a longitudinal and vertical plane of the lighting device. Detailed description

[0027] Figure 1 illustrates a lighting device for a motor vehicle according to an embodiment of the invention. The lighting device 1 is configured to display one or more pixelated light patterns, in particular to signal the presence of the motor vehicle and / or to transmit information to an observer located at a distance from the lighting device 1. The lighting device 1 is intended to be integrated into a motor vehicle and includes a fairing for this purpose. According to the embodiment presented, the lighting device 1 is intended to be integrated into a left edge of the front of the vehicle, extending from a left fender and the hood of the vehicle. Alternatively, the lighting device 1 could be adapted to be integrated into any other part of the vehicle.

[0028] In this document, the X-axis designates the longitudinal axis of a vehicle. When moving forward in a straight line, the vehicle progresses from rear to front in a direction parallel to its longitudinal axis. The X-axis is oriented from the front to the rear of the vehicle, that is, in the direction of reverse. The Y-axis designates the transverse axis of the vehicle. The Y-axis is oriented from left to right, with left and right defined from the perspective of a driver of the vehicle. The Z-axis designates the axis perpendicular to the X-axis and the Y-axis. The vehicle is assumed to be resting on a horizontal surface. The Z-axis is a vertical axis, oriented from bottom to top. The X, Y, and Z axes form an orthogonal coordinate system. This same coordinate system, defined with reference to a vehicle, will also be used to describe the lighting device 1, even when considered outside the vehicle, since it is intended for mounting in a specific orientation within the vehicle.

[0029] The lighting device 1 includes a transparent or translucent cover 2 through which light rays are emitted. The cover 2 is intended to protect the lighting device. The cover 2 may include a microstructured optical film that allows for modification of the light distribution of the lighting device. This film may be attached to the cover by overmolding or by any other mechanical means.

[0030] The window 2 is curved along at least two non-parallel axes. A first axis may be at least roughly parallel to the transverse axis Y. The window 2 thus includes a first rounded line L1, notably upwards and towards the rear. This first rounded line L1 connects a roughly vertical front face to a roughly horizontal hood. A second axis may be at least roughly parallel to the vertical axis Z. The window 2 thus includes a second rounded line L2, notably towards the left and towards the rear. This second rounded line L2 connects the front face, roughly parallel to the transverse axis Y, to the left fender of the vehicle, roughly perpendicular to the transverse axis Y. The window 2 thus has an overall ellipsoidal shape.

[0031] In Figure 1, the glass 2 of the lighting device was removed to observe the underlying components of the lighting device 1. The lighting device 1 comprises a grid 3 equipped with a set of cells 31. Each cell 31 cooperates with a light source of the lighting device so as to project a pixelated image. The grid 31 is therefore designed to optically decouple the different light sources of the lighting device. According to the embodiment shown, the grid 3 comprises three vertically superimposed rows from bottom to top, comprising nine, ten, and ten cells respectively. The lighting device 1 is thus designed to project an image comprising twenty-nine pixels. Alternatively, the number of rows and the number of cells in each row could, of course, be different. For example, the grid 3 could comprise between fifteen and sixty cells.

[0032] The grid 3 includes an exit face 32 extending against the ice 2. The exit face 32 therefore has a shape that is generally identical to the ice 2, specifically an ellipsoidal shape characterized by a double curvature along at least two non-parallel axes. The grid 3 can have approximately the same dimensions as the ice 2 along the vertical axis Z and along the transverse axis Y.

[0033] In the figure, grid 3 is shown in isolation. The cells 31 of grid 3 are openings extending through the thickness of the grid. The cells 31 extend from an entrance face 33 to the exit face 32. The entrance face 33 and the exit face 32 are two opposite faces of grid 3. According to the embodiment shown, the cells have a generally oval shape, elongated horizontally. Alternatively, the shape of the cells 31 could be different, for example, circular, rectangular, or square.

[0034] Preferably, grid 3 is made of a flexible material such as silicone or an elastomer, in particular EPDM, i.e., ethylene propylene diene monomer. Furthermore, grid 3 is opaque so as to optically isolate each cell 31.

[0035] On the, not only the glass 2 but also the grid 3 of the lighting device 1 have been removed. It can thus be observed that the lighting device 1 comprises a support 4 intended to be fixed to the motor vehicle, a first printed circuit board 5 comprising a first set of light-emitting diodes 51, a second printed circuit board 6 comprising a second set of light-emitting diodes 61, and a third printed circuit board 7 comprising a third set of light-emitting diodes 71. According to an alternative construction, the lighting device could comprise only two of the three printed circuit boards 5, 6, 7 or, on the contrary, four or even more printed circuit boards.

[0036] Each printed circuit board 5, 6, 7 can be in the form of a horizontally elongated strip. The printed circuit boards 5, 6, 7 are adjacent to each other, and in particular positioned one above the other. Furthermore, the printed circuit boards 5, 6, and 7 are offset from each other along the longitudinal axis X. The printed circuit boards 5, 6, and 7 are therefore offset along a third axis perpendicular to the two non-parallel axes defining the curvature of the glass 2. This offset allows the curvature identified by the first rounded line L1 in Figures 1 and 2 to be reproduced. The first printed circuit board 5 is positioned further forward than the second printed circuit board 6, which is itself positioned further forward than the third printed circuit board 7. The light-emitting diodes 51, 61, and 71 can be distributed at regular intervals on the printed circuit boards 5, 6, and 7, respectively.

[0037] Furthermore, each printed circuit board 5, 6, 7 is at least locally curved, i.e., not flat. The curvature of the printed circuit boards 5, 6, 7 allows for the reproduction of the curve identified by the second rounded line L2 in Figures 1 and 2. The printed circuit boards 5, 6, 7 are therefore advantageously flexible printed circuit boards, also known by the English term "flex PCB".

[0038] Printed circuit boards 5, 6, and 7 are curved respectively along three curved lines Lc1, Lc2, and Lc3. These three curved lines are preferably non-parallel, meaning they are not superimposable. In one embodiment, the first printed circuit board 5 can be curved around a first axis Z1. Similarly, the second printed circuit board 6 can be curved around a second axis Z2, and the third printed circuit board 7 can be curved around a third axis Z3. The radii of curvature of each printed circuit board around its respective axis can be different. The three axes Z1, Z2, and Z3 can be parallel to each other, and in particular parallel to the vertical Z-axis. The three axes Z1, Z2, and Z3 can coincide, as shown in the diagram, or, conversely, be offset from each other. Each printed circuit board may include a flat portion and at least one curved portion.The radius of curvature of each printed circuit board can vary along the length of the circuit board. According to one embodiment of the invention, one or more printed circuit boards could be curved around at least two axes, preferably parallel to each other, and thus exhibit a wave shape.

[0039] Light-emitting diodes 51, 61, 71 form the light sources of the lighting device 1. Each light-emitting diode 51, 61, 71 is connected to a printed circuit board 5, 6, 7, which is itself connected to an electrical power source in the vehicle. The term "light-emitting diode" refers to any type of light-emitting diode, such as LEDs (Light Emitting Diode), OLEDs (Organic LED), AMOLEDs (Active-Matrix Organic LED), or FOLEDs (Flexible OLED).Advantageously, the LEDs are selectively controlled by a control unit that regulates the electrical supply current for each light source to control their light emission. This allows the LEDs to be selectively controlled and configured in any state between off and maximum brightness.

[0040] Each LED is positioned opposite a cell 31 of grid 3. The LEDs 51 are positioned opposite the bottom row of cells, the LEDs 71 are positioned opposite the middle row of cells, and the LEDs 71 are positioned opposite the top row of cells. Conversely, at least one LED 51, 61, or 71 is positioned opposite each cell 31 of grid 3.

[0041] In this case, the oval shape of the cells allows for the arrangement of several LEDs within each cell, for example, three LEDs opposite each cell. Each cell can thus be brighter and / or project light beams of a different color. Alternatively, the number of LEDs opposite each cell could vary, for example, one, two, four, or even more LEDs.

[0042] According to a first embodiment, each cell 31 comprises a profiled shape between the inlet face 33 and the outlet face 32. The light-emitting diodes (LEDs) positioned opposite each cell 31 are therefore not decoupled from one another. According to a second embodiment illustrated in the figure, each cell 31 can be compartmentalized so as to decouple the LEDs positioned opposite each other within the same cell. For this purpose, each cell 31 can comprise recesses 34, for example, conical or frustoconical in shape, each recess being positioned opposite an LED.

[0043] The support 4 is shown in isolation in the figure. The support 4 supports the printed circuit boards 5, 6, 7, the grid 3, and the glass 2. The support 4 includes an outer edge 41 provided with tabs 42 by means of which the support can be attached to the vehicle. The support 4 also includes three surfaces 43, 44, 45, in particular three vertical surfaces, along which the printed circuit boards 5, 6, 7 extend respectively. In particular, the support includes a step-like structure, each surface 43, 44, 45 being formed by a riser of this structure. The support 4 may be a plastic element, preferably obtained by molding.

[0044] Printed circuit boards 5, 6, and 7 are fixed to the support 4, respectively against the three surfaces 43, 44, and 45. Surfaces 43, 44, and 45 are also curved around axes Z1, Z2, and Z3, respectively. It is the contact of the circuit boards 5, 6, and 7 against the three surfaces 43, 44, and 45 that gives the printed circuit boards their curved shape. Advantageously, each printed circuit board 5, 6, and 7 is fixed to its respective surface 43, 44, and 45 with two fastening means arranged at two opposite ends of the circuit board. The fastening means can be, for example, screws, rivets, or even mounting pins, such as dowel pins. The support 4 can thus be equipped with first mounting holes 46 cooperating with said fastening means.In addition, to improve the positioning accuracy of the light-emitting diodes, the support 4 includes a first set of positioning pins 47 cooperating with second holes formed in each printed circuit board 5, 6, 7.

[0045] Furthermore, the printed circuit boards 5, 6, 7 can each include an electrical connector, and the support can include an opening 49 through which the electrical connectors of the different printed circuit boards 5, 6, 7 are arranged. Although offset from each other, the printed circuit boards 5, 6, 7 can thus be connected to the same electrical harness.

[0046] The grid 3 is compressed, or in other words, clamped, between the support 4 and the glass 2. The grid 3 is thus sandwiched and completely immobilized. The entrance face 33 of the grid 3 extends opposite the support 4 and the printed circuit boards 5, 6, and 7. The entrance face 33 also has a stepped structure that conforms to the shape of the support 4. Advantageously, the grid is made of a material that is more flexible than the support 4 and more flexible than the glass 2. The grid 3 can therefore deform to conform to the precise shapes of the glass 2 and the support 4. This ensures that there is no air gap between the grid and the support or between the grid and the glass, which could have caused light leakage. The glass 2 is advantageously fixed to the support 4 so as to exert a compressive force on the grid 3. The glass 2 can in particular be fixed to the support 4 by fixing clips.The reaction force exerted by the grid 3 on the support 4 and on the glass 2 can advantageously put tension on the fixing clips and contribute to the good retention of the glass 2 to the support 4.

[0047] To improve the positioning accuracy of grid 3 relative to support 4, grid 3 includes a second set of positioning pins 35 cooperating with third holes 52, 62, 72 formed on each printed circuit board 5, 6, 7 and cooperating with fourth holes 48 formed in support 4 opposite third holes 52, 62, 72.

[0048] The thickness of the grid 3 between its entrance face 33 and its exit face 32 may vary. The light-emitting diodes 51, 61, and 71 are thus located at different distances from the exit face 32. In order to maintain the same brightness for each cell of the lighting device, the size of the cells 31 is increased proportionally according to the local distance of the exit face 32 from the corresponding light-emitting diode(s). In particular, an illumination coefficient S / H is defined as the ratio of the illuminated area S of a given cell 31 to the depth H of that cell. The illuminated area S of a cell corresponds to the area of ​​that cell at the level of the exit face 32. As an example, the illuminated area S of a particular cell is hatched on the diagram.The depth H of a cell corresponds to the distance between the LED(s) associated with the cell and the illuminated surface S. The depth H of a particular cell is illustrated by an arrow on the diagram. Advantageously, the illumination coefficients of each cell 31 of grid 3 are substantially equal. By "substantially equal" we understand that all the illumination coefficients are within a range of plus or minus 20% around an average value of the illumination coefficient, or even a range of plus or minus 10% around an average value of the illumination coefficient.

[0049] To manufacture the lighting device 1, the following procedure can be used. First, the printed circuit boards 5, 6, 7, the grid 3, the support 4, and the lens 2 are provided as separate parts. Next, the printed circuit boards 5, 6, 7 are placed on the support 4, with the printed circuit boards 5, 6, 7 being curved respectively along the curved surfaces 41, 42, 43. The positioning pins 47 are aligned with the corresponding holes in the printed circuit boards, and the printed circuit boards are secured at each end. Then, the grid 3 is placed against the support 4, followed by the printed circuit boards 5, 6, 7. In particular, the positioning pins 35 are aligned with the corresponding holes 48, 52, 62, 72 in the support and in the printed circuit boards.Finally, the glass 2 is fixed to the support 4, which has the effect of pressing the inlet face 33 of the grid 3 against the support 4, and of pressing the outlet face 32 against the glass 2.

[0050] Ultimately, the result is a lighting device that is easy to manufacture and features excellent decoupling between the individual light cells. Furthermore, the lighting device has a doubly curved surface that allows for seamless integration with the vehicle. This double curve also makes the lighting device at least partially visible from multiple directions. Despite this curve, each cell of the lighting device appears equally bright. The vehicle is thus clearly visible to other road users. The pictograms or symbols produced by the lighting device remain clearly visible.

Claims

A lighting device (1) for a motor vehicle, characterized in that it comprises: - a first curved printed circuit board (5) comprising a first set of light-emitting diodes (51), - at least a second curved printed circuit board (6) comprising a second set of light-emitting diodes (61), the second printed circuit board being adjacent to the first printed circuit board and offset from the first printed circuit board, - a grid (3) comprising a plurality of cells (31), each cell being positioned with respect to at least one light-emitting diode of the first set of light-emitting diodes or of the second set of light-emitting diodes, the grid comprising an input face (33) extending opposite the first printed circuit board and opposite the second printed circuit board,the grid comprising an exit face (32) curved along at least two non-parallel axes. Light device (1) according to the preceding claim, characterized in that each cell (31) of the grid comprises a lighting coefficient defined by the ratio of the lighting area (S) of the cell considered to the depth (H) of the cell considered, all cells of the grid comprising a substantially equal lighting coefficient. Light device (1) according to any one of the preceding claims, characterized in that the grid (3) is made of a flexible material such as silicone or an elastomer, in particular an EPDM. A lighting device according to one of the preceding claims, characterized in that the first printed circuit board (5) is curved along a first curved line (Lc1), and in that the second printed circuit board (6) is curved along a second curved line (Lc2), the first curved line (Lc1) being not parallel to the second curved line (Lc2). A lighting device (1) according to any one of the preceding claims, characterized in that it further comprises at least one third curved printed circuit board (7) comprising a third set of light-emitting diodes (71), the third printed circuit board being adjacent to the first printed circuit board and the second printed circuit board, the third printed circuit board being offset from the first printed circuit board and from the second printed circuit board, each cell (31) of the grid (3) being positioned with regard to at least one light-emitting diode of the first set of light-emitting diodes or the second set of light-emitting diodes or the third set of light-emitting diodes, the input face (33) of the grid also extending opposite the third printed circuit board. A lighting device (1) according to any one of the preceding claims, characterized in that it further comprises: - a support (4), intended to be fixed to a motor vehicle, the first printed circuit board (5) and the second printed circuit board (6) being fixed to the support, and - a transparent or translucent closing glass (2) covering the grid (3), the grid being trapped between the support and the glass. Light device (1) according to the preceding claim, characterized in that the grid (3) is made of a material more flexible than the support and more flexible than the ice, the grid being compressed between the ice and the support. A lighting device (1) according to any one of claims 6 or 7, characterized in that the support (4) comprises: - a first curved surface (43), the first printed circuit board (5) extending against the first surface and being fixed to the first surface with two fixing means arranged at two opposite ends of the first printed circuit board, and - a second curved surface (44), the second printed circuit board (6) extending against the second surface and being fixed to the second surface with two fixing means arranged at two opposite ends of the second printed circuit board. A lighting device according to any one of claims 6 to 8, characterized in that: - the support (4) comprises a first set of positioning pins (47) cooperating with holes formed in the first printed circuit board and / or in the second printed circuit board, and / or in that - the grid (3) comprises a second set of positioning pins (35) cooperating with holes (48, 52, 62) formed in the first printed circuit board and / or in the second printed circuit board and / or in the support. Method of manufacturing a lighting device according to any one of claims 6 to 9, characterized in that it comprises: - the supply of the first printed circuit board (5), the second printed circuit board (6), the grid (3), the support (4) and the glass (2), then - the placement of the first printed circuit board and the second printed circuit board on the support, then - the placement of the grid against the support, the first printed circuit board and the second printed circuit board, then - the placement of the glass against the grid.

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