Light module for a motor vehicle signalling device

Abstract

The invention relates to a light module (1) for a motor vehicle signalling device, the module comprising a plurality of selectively controllable light sources (2); each light source comprising an elementary light generator and a photoluminescent element that covers the elementary light generator and is able to absorb rays of light emitted by this generator and to emit, in response, light rays of different wavelengths, characterised in that each light source comprises a plurality of walls made of a white-coloured material, each wall coming into contact with a lateral surface of the photoluminescent element and the plurality of walls defining an enclosure that surrounds the photoluminescent element of this light source.

Description

Description Title of the invention: Light module of a signaling device of a motor vehicle

[0001] The invention relates to the field of automotive lighting and light signaling. More specifically, the invention relates to the field of screens integrated into light modules for lighting or light signaling of motor vehicles.

[0002] It is known to integrate screens into lighting devices of motor vehicles, for example in rear lights. These screens are for example produced by means of matrices of a large number of light sources, selectively controllable, whose dimensions are sufficiently small so that it is possible to display information on these screens, for example in the form of a message or pictogram, with a satisfactory resolution. This information thus makes it possible to improve the signaling of the motor vehicle, for example by contextualizing or accompanying a given signaling function with a message.

[0003] This type of screen for this type of application raises several challenges.

[0004] In fact, the light sources used in these screens are generally composed of a semiconductor chip emitting blue light, covered with a photoluminescent material capable of absorbing part of this blue light and re-emitting yellow light in response, the light resulting from the composition of the rest of the blue light and the yellow light being white in color.

[0005] However, this photoluminescent material has a high albedo, or reflectance, and can significantly reflect light incident on the screen, such as sunlight or light from exterior lighting in the vehicle. This albedo is therefore likely to reduce the contrast of the screen and therefore impair the visibility of the details of the pictograms or messages displayed on the screen.

[0006] Furthermore, the photoluminescent material, given its properties, has a yellow or amber color, which is visible from outside the screen. When the screen is off, it also has a yellow appearance, which is incompatible with the need for neutrality of the off appearance of the screens.

[0007] It is therefore appropriate on the one hand to reduce the size of the light sources as much as possible, in order to minimize the dimensions of the visible surface of this photoluminescent material to reduce its albedo and reduce the impact of the color of this material on the off appearance of the screen. Reducing the size of the light sources also makes it possible to reduce the pitch separating two light sources and therefore increase the resolution of the screen.

[0008] It is also necessary to avoid interference effects between light sources and in particular to prevent light emitted by one light source from illuminating and reflecting on a neighboring light source. This effect, also called cross-talk, has the consequence of reducing the quality of the perceived from the screen and in particular its contrast, to the extent that a light source that is switched off may appear to be switched on. However, the smaller the dimensions of the light sources and the closer they are to each other, the more pronounced this parasitic effect is.

[0009] There is thus a need for a light module equipped with a plurality of light sources capable of together forming a screen for a signaling device of a motor vehicle, the efficiency of which is optimal while having a reduced albedo and a neutral extinguished appearance.

[0010] The present invention is placed in this context, and aims to meet this need.

[0011] For these purposes, the subject of the invention is a light module of a signaling device of a motor vehicle, comprising a plurality of selectively controllable light sources; each light source comprising an elementary light generator and a photoluminescent element covering the elementary light generator and capable of absorbing light rays emitted by this generator and of emitting, in response, light rays of different wavelength, characterized in that each light source comprises a plurality of walls made of a white material, each wall coming into contact with a lateral surface of the photoluminescent element and the plurality of walls defining an enclosure framing the photoluminescent element of this light source.

[0012] The invention thus proposes to modify the structure of each of the light sources of a light module intended to form a screen, by adding white-colored walls or partitions, coming into contact with the photoluminescent element to completely surround it. These walls make it possible, on the one hand, to intercept light emitted by the generator and which would be likely to reach another light source of the light module. Due to their white color, this light is reflected in the enclosure defined by the walls and in which the material of the photoluminescent element is located. These walls therefore significantly reduce the effects of interference or cross-talk and increase the efficiency of the light module. It is therefore possible to reduce the dimensions of the light sources to reduce the albedo of the light source.In addition, the edges, or thicknesses, of these white walls contribute to the visible, off appearance of the light module and therefore reduce the influence of the color of the photoluminescent element on this off appearance. Preferably, each light source has its own walls, i.e. they are distinct from the walls of the other light sources. In this way, the light sources can be arranged in an adaptable manner; in particular, the geometry of an arrangement of light sources can be freely modified. Similarly, the spacing between the light sources is freely adaptable. Thus, the light source can be used in a standard manner for a multitude of configurations, which allows economies of scale.

[0013] In the invention, the elementary light generator may be a light-emitting semiconductor chip. The semiconductor may, for example, be a gallium nitride, or GaN, capable of emitting, by electroluminescence and in response to an electric current passing through it, rays of blue light. The photoluminescent element may, for example, be in the form of a resin comprising a cerium-doped yttrium aluminum garnet, or CE:YAG, capable of absorbing blue light and, by photoluminescence and in response to the excitation carried out by this light, emitting rays of yellow light. The photoluminescent element is arranged on the generator so that part of the blue light rays excites this element so that it emits, by photoluminescence, rays of yellow light. The other part of the blue light rays pass through this element. Thus, the light source emits simultaneously, when it is electrically powered, rays of blue and yellow light, the light thus formed appearing white to the human eye.

[0014] According to the invention, the white-colored material may be a dielectric material, having a reflection coefficient of between 60 and 99%, in particular substantially equal to 90%. It may, for example, be a silicone resin enriched with titanium dioxide (TiO2). Where appropriate, each wall made of the white-colored material may have a thickness of at most 100 μm.

[0015] Advantageously, the elementary light generator of each light source is mounted on a support and each of the walls of said light source is mounted on this support and extends to an upper surface of the photoluminescent element. Said support may be a printed circuit board or a substrate called an “interposer”. In this embodiment, the photoluminescent element thus encapsulates the elementary generator and the white walls extend against the photoluminescent element up to the level of the upper surface of the photoluminescent element.

[0016] In one embodiment, the light sources are encapsulated in the same layer of dark-colored material. This layer of dark-colored material thus extends between two neighboring light sources, coming into contact with the external lateral surfaces of the white walls. Given its opacity and its color, it thus makes it possible to further limit the effects of interference or cross-talk which could persist, despite the presence of the white walls, to improve the extinguished appearance of the light module and to reduce its albedo.

[0017] Advantageously, a portion of the layer of dark-colored material may extend above the walls of white material and the photoluminescent elements of the light sources. If necessary, the thickness of this portion may be between 10 μm and 200 μm. This characteristic makes it possible to further improve the off appearance of the screen and to reduce its albedo.

[0018] Advantageously, the dark-colored material may be black or gray and have a transmission coefficient, in the mass, of, for example, between 50% and 95% over a thickness of 1 mm, or between 50% and 95% over a thickness of 100 pm, which is particularly suitable when a portion of the layer of dark-colored material extends above the walls of white material and the photoluminescent elements of the light sources and the thickness of this portion is between 10 pm and 200 pm. Indeed, a low transmission coefficient over a distance of the order of the thickness covering the light sources makes it possible to avoid stray lights due to reflections of the light leaving the layer of dark material. It could, for example, be a polymer, in particular an epoxy resin or a silicone, enriched with, preferably, carbon particles or black pigments. It could, for example, be envisaged that the concentration of carbon particles, namely the mass of carbon relative to the mass of the polymer, is less than 0.05%. This characteristic is particularly suitable when the light module is intended to perform a regulatory signaling function.Otherwise, it may be possible to consider that the concentration of carbon particles is greater than 0.05%, in particular in order to improve the contrast and the off-screen appearance.

[0019] In one embodiment of the invention, the light module comprises a printed circuit board on which the elementary light generator of each light source is mounted, each generator comprising at least two electrical connection pads via which it is mounted and interconnected to said printed circuit board.

[0020] In another embodiment of the invention, the light module comprises a printed circuit board, and each light source comprises a substrate, the elementary light generator of each light source comprising at least two electrical connection pads via which it is mounted on this substrate, and each light source is mounted and interconnected to said printed circuit board via its substrate. In this embodiment, the substrate, also called an interposer, supports the elementary light generator, and allows the mounting and electrical interconnection of the light source to a printed circuit board. It may be provided that the elementary light generator is encapsulated between the photoluminescent element and the substrate, the substrate thus supporting both the elementary light generator, the photoluminescent element and the walls made of white material.

[0021] Advantageously, each wall of white material extends from the substrate and each substrate comprises two electrical connection pads via which it is mounted and interconnected to said printed circuit board, these pads each extending on a lower face of the substrate from a lateral edge of the substrate and each having a width such that these pads are separated by a space of at most 100 μm, in particular 80 μm. In this example, the size of the mounting surface of the light source on the printed circuit board, defined by the surface of the substrate, is increased, due to the walls of white material. It is then possible to take advantage of this increase to move the positioning of connection pads, usually centered on the substrate, towards the edges of the substrate and to increase their widths, with respect to the width of the substrate measured between these edges. These pads can then be more easily positioned, by a machine, on a given location on the printed circuit board, which therefore improves the precision of the assembly. In addition, the thermal conduction between the printed circuit board and the light source is improved, and the increase in the space between the two pads makes it possible to avoid electromigration phenomena which are harmful to the reliability of the light source.

[0022] Advantageously, the elementary light generator of each of the light sources comprises at least one light-emitting semiconductor chip whose dimensions are between 100 pm and 400 pm. Such a chip is known in particular as a mini-LED. Where appropriate, the light sources may be arranged on the first face of the substrate so as to be spaced apart from each other by a distance of less than 1 millimeter.

[0023] Alternatively, the elementary light generator of each of the light sources comprises at least one light-emitting semiconductor chip whose dimensions are between 5 pm and 150 pm. Such a chip is known in particular as a microLED. Where appropriate, the light sources may be arranged on the first face of the substrate so as to be separated from each other by a distance of between 200 and 400 pm, or even less than or equal to 300 pm. Here, the term "distance between two light sources" means the distance separating the center of one of these light sources from the center of the other of these light sources.

[0024] Preferably, the light sources are configured to emit white light. Alternatively, the light module comprises combinations of light sources of several types, for example some of the light sources capable of emitting, for example, white light and other light sources amber light. Other combinations of light sources are particularly relevant for an automotive application: • amber / white • cyan / white • cyan / red • amber / white / cyan • red / white / cyan • RGB

[0025] Preferably, the light sources comprise a single light generating element. In this way, the reduction of interference or crosstalk effects is reduced in the most advantageous way.

[0026] Advantageously, the light module comprises a connector for receiving a control instruction from said plurality of light sources. Where appropriate, the plurality of light sources forms a passive matrix and the controller is arranged to control said passive matrix according to the control instruction. received by the connector. For example, the light module may comprise a plurality of devices for controlling the electrical power supplied to the light sources, each control device being mounted on a first face of the printed circuit board, in line with a light source, to control the electrical power supplied to the light source, in particular as a function of an instruction received from the controller intended for it.

[0027] Advantageously, the light module comprises at least 500 light sources, in particular distributed in a matrix manner, the controller being arranged to selectively control each of these light sources. If desired, said plurality of light sources may be a first plurality of light sources and the controller may be a first controller, and the light module may comprise at least a second plurality of light sources, for example mounted on the first face of the printed circuit board while being adjacent to the first plurality of light sources, and a second controller capable of selectively controlling each of the light sources of the second plurality.

[0028] Advantageously, the light module comprises an interconnection system connected to the controller and arranged to interconnect the controller to the plurality of light sources. The interconnection system may be integrated into the printed circuit board or be an independent element mounted on this printed circuit board. The interconnection system may comprise a matrix of connectors, such as a ball grid array (BGA) or a pad matrix (LGA).

[0029] The invention also relates to a signaling device for a motor vehicle, characterized in that it comprises a light module according to the invention, said plurality of light sources forming a light screen of said signaling device.

[0030] The invention also relates to a method of manufacturing a light source of a light module according to the invention, the method comprising the following steps: • Assembly of at least one elementary light generator on a support; • Deposition of a layer of photoluminescent material on the elementary light generator; • Cutting the photoluminescent material to form a photoluminescent element covering the elementary light generator; • Deposition of a layer of white material on the photoluminescent element-elementary light generator assembly; • Cutting the white material to form a plurality of walls each coming into contact with a lateral surface of the photoluminescent element and defining an enclosure framing the photoluminescent element

[0031] The assembly step could, for example, be a step of mounting a light-emitting semiconductor chip on the surface of the support, the support being able, for example, to be an interposer.

[0032] The step of cutting the photoluminescent material may, for example, include the formation of grooves in the photoluminescent material around an area intended to form the photoluminescent element, the grooves being intended to receive white-colored material to form the walls.

[0033] The method may advantageously include, subsequent to the step of depositing the layer of white material, a step of polishing an upper surface of the photoluminescent element-elementary light generator-layer of white material assembly.

[0034] The present invention is now described using examples which are purely illustrative and in no way limitative of the scope of the invention, and from the appended drawings, drawings in which the various figures represent:

[0035] [Fig. 1] represents, schematically and partially, a front view of a light module according to one embodiment of the invention;

[0036] [Fig. 2] represents, schematically and partially, a side view of the light module of [Fig. 1];

[0037] [Fig. 3] represents, schematically and partially, a bottom view of a light source of the light module of [Fig. 1]; and

[0038] [Fig. 4] represents, schematically and partially, a side view of a light module according to another embodiment of the invention.

[0039] In the following description, elements which are identical, by structure or by function, appearing in different figures retain, unless otherwise specified, the same references.

[0040] [Fig. 1] describes a front view of a light module 1 according to an embodiment of the invention. In the example described, this light module 1 is intended to be integrated into a front light of a motor vehicle, the light module 1 forming a screen. [Fig. 2] describes a side view of this light module 1.

[0041] The light module 1 comprises a plurality of light sources 2 mounted on a support 3, formed in the example described by a printed circuit board 3.

[0042] In the example described, the light module 1 comprises more than 20,000 light sources 2, arranged in a matrix fashion, on 256 columns and 80 rows. The light sources 2 are mini-LEDs, the dimensions of which are between 100 pm and 400 pm. The light sources 2 are spaced apart from each other by a distance less than or equal to 1 mm. It should be noted that other dimensions of the light sources, other distances between the light sources, other numbers of light sources or even other distributions of the light sources could be envisaged, without departing from the scope of the present invention.

[0043] The printed circuit board 3, or PCB, has a first face 31 and a second face 32 opposite the first face. The light sources 2 are mounted on the first face 31 of the PCB 3, which faces the outside of the signaling device in which the light module 1 is integrated.

[0044] It should be noted that, in the example described, the printed circuit board 3 is a so-called PCB multilayer, comprising a stack of layers, between the first and second faces 31 and 32. These layers are in particular intended for the interconnection of the components mounted on the PCB, and may each comprise a plurality of through-vias, blind or buried, arranged in the PCB 3 to be connected to the different interconnection layers. These vias open onto the first face 31 or the second face 32 of the PCB 3 at the level of metal pads to which they are connected.

[0045] In order to be able to control the light sources 2, the light module 1 comprises at least one controller 4 capable of selectively controlling light sources 2. It could be envisaged that a single controller 4 controls all of the light sources 2 mounted on the PCB 3 or that a plurality of controllers 4 are provided, each selectively controlling a matrix, for example 64x64, i.e. 4096, light sources 2.

[0046] The light module 1 comprises a connector (not shown) for receiving an instruction for controlling said plurality of light sources 2. This may for example be an instruction issued by a computer of the motor vehicle or of the signaling device for the display of a logo, a message, a pattern or a pictogram. For example, this may be an instruction for displaying a pictogram intended to inform an outside observer of the opening of a door of the motor vehicle, a pictogram intended to inform a motorist following the motor vehicle of the presence of black ice on the road or information relating to motor traffic.

[0047] The plurality of light sources 2 forms a passive matrix where each row and each column of light sources 2 is associated with a control device (not shown) mounted on the PCB 3 at the right of this row or this column to control the electrical power supplied to the light sources of this row or this column. The controller 4 is thus arranged to control each of the sources 2 of said passive matrix according to the control instruction received by the connector, by successively scanning the rows then the columns of the matrix to control the electrical power supplied to each of the light sources 2.

[0048] In the example described, the controller 4 is mounted on the second face 32 of the PCB 3 and is electrically interconnected to the metal pads provided on this second face 32. This interconnection can be achieved for example via a matrix of connectors (not shown), such as a matrix of balls, also called BGA (from the English “ball grid array”).

[0049] Each light source 2 comprises a light-emitting semiconductor chip 21, forming an elementary light generator. The semiconductor may, for example, be a gallium nitride, or GaN, capable of emitting, by electroluminescence and in response to an electric current passing through it, rays of blue light, for example the spectrum of which has a peak centered on a wavelength between 410 nm and 480 nm.

[0050] Each light source also comprises a photoluminescent element 22. This element 22, also called a conversion element or phosphor, is capable of absorbing a portion of the light rays emitted by the chip 21 and of emitting, in response, light rays of different wavelengths. The photoluminescent element may, for example, be in the form of a resin comprising a cerium-doped yttrium aluminum garnet, or CE:YAG, capable of absorbing blue light and, by photoluminescence and in response to the excitation produced by this light, of emitting yellow light rays, for example the spectrum of which has a peak centered on a wavelength between 520 nm and 600 nm.

[0051] The photoluminescent element 22 is arranged on the chip 21 so that a portion of the blue light rays emitted by the chip 21 excites this element 22 so that it emits, by photoluminescence, yellow light rays. The other portion of the blue light rays passes through this element. Thus, the light source 2 simultaneously emits, when electrically powered, blue and yellow light rays, the light thus formed appearing white to the human eye.

[0052] In the embodiment of [Fig. 2], each light source 2 further comprises an interposer 23 on which the chip 21 is mounted via two electrical connection pads 21a. The chip 21 is thus encapsulated between the photoluminescent element 22 and the interposer 23.

[0053] Each light source 2 also comprises a plurality of walls 24 made of a white material. The white material may be a dielectric material, having a reflection coefficient of between 60 and 99%, in particular equal to 90%, such as a silicone resin enriched with titanium dioxide (TiO2).

[0054] Each wall 24 extends from the interposer 23, coming into contact with a lateral surface of the photoluminescent element 22, to an upper surface of the photoluminescent element 22. The walls 24 comprise internal surfaces thus extending against the photoluminescent element 22 until they come flush with the upper surface of the photoluminescent element 22, and thus defining an enclosure framing the photoluminescent element 22. The white walls 24 further comprise external lateral surfaces, opposite the internal surfaces.

[0055] Given the white color of these walls 24, light rays which would be emitted by the chip 21 of a light source 2 in the direction of another light source 2 are intercepted by these walls 24 and reflected in the direction of the photoluminescent element 22, which thus makes it possible to avoid parasitic effects and to increase the efficiency of the light module 1. In addition, the edges, or the thicknesses, of these white walls 24 contribute to the visible extinguished appearance of the light module and therefore reduce the influence of the color of the photoluminescent element 22 on this extinguished appearance.

[0056] Each light source 2 is mounted and interconnected to said printed circuit board 3 via the interposer 23. As shown in [Fig. 2], the interposer 23 comprises two electrical connection pads 23a, via which the light source 2 is mounted on the first face 31 of the PCB 3 and is electrically interconnected to electrical tracks provided on this first face 31.

[0057] As shown in [Fig. 3], which represents a bottom view of a light source 2, each electrical connection pad 23a extends on the lower face of the interposer 23, from a lateral edge 23b of the substrate. Each pad 23a extends over almost the entire length of the interposer 23. The pads 23a are separated from each other by a space of at least 80 μm.

[0058] This arrangement and these dimensions of the pads 23a are made possible by the increase in the surface area of ​​the interposer 23, due to the walls made of white material 24. The pads 23a can then be more easily positioned, by a machine, on a given location of the printed circuit board 3, which therefore improves the precision of the assembly. In addition, the thermal conduction between the printed circuit board 3 and the light source 2 is improved, and the increase in the space between the two pads 23a makes it possible to avoid electromigration phenomena which are harmful to the reliability of the light source 2.

[0059] All of the light sources 2 are encapsulated in the same layer of dark-colored material 5, for example black or gray, having a mass transmission coefficient of between 50% and 95%, over a thickness of 1 mm. It could, for example, be a polymer, in particular a silicone enriched with carbon particles, the concentration of carbon particles being less than 0.05%.

[0060] This layer 5 thus extends between two neighboring light sources 2, coming into contact with the external lateral surfaces of the white walls 24. Given its opacity and its color, the layer 5 thus makes it possible to further limit the effects of interference or crosstalk, and contributes to improving the extinguished appearance of the light module 1 and to reducing its albedo. Preferably, the layer 5 also covers the PCB 3, forming for example a thickness of between 200 pm and 1 mm. In this way, an extinguished appearance is improved, while further reducing the effects of interference or crosstalk between the light sources.

[0061] Furthermore, a thin portion 51 of the layer 5 extends above the walls 24 and the photoluminescent elements 22 of the light sources 2. This characteristic makes it possible to further improve the extinguished appearance of the light module and to reduce its albedo.

[0062] For example, it may be provided that each wall 24 has a thickness of at most 100 pm, and that the thickness of the portion 51 of the layer 5 is between 10 pm and 200 pm.

[0063] An example of a method for manufacturing a light source 2 of a light module 1 according to the embodiment of [Fig. 1] to [Fig. 3] will now be described.

[0064] In a first step, the light-emitting semiconductor chip 21, in the form of a “die”, is assembled to the interposer 23, the pads 21a being soldered or brazed or glued to the interposer 23.

[0065] A layer of photoluminescent material is deposited, for example by molding, on the chip 21. Grooves are then formed, for example by laser drilling or by blade dicing, in this layer of photoluminescent material, to delimit the shape of the photoluminescent element 22.

[0066] A layer of white material is then deposited on the layer of photoluminescent material, to fill the grooves, and form the walls 24. The excess white material, protruding from the grooves, is polished so that the levels of the layers of white material and photoluminescent material are identical.

[0067] Finally, the assembly is cut out, at the level of the walls 24, to form the light source 2.

[0068] [Fig. 4] shows a side view of a light module 10 according to another embodiment of the invention.

[0069] In this embodiment, the light sources 2 are devoid of an interposer. Each light source 2 is thus mounted on the printed circuit board 3 via its chip 21, the electrical connection pads 21a being mounted and interconnected directly to the printed circuit board 3.

[0070] The preceding description clearly explains how the invention makes it possible to achieve the objectives it has set itself, namely to propose a light module capable of forming a screen of a signaling device of a motor vehicle, the efficiency of which is optimal while having a reduced albedo and a neutral extinguished appearance. It is thus understood that these objectives are notably achieved by integrating into each light source of the screen white colored walls or partitions coming into contact with the photoluminescent element of this light source to completely surround it. These white walls make it possible to significantly reduce the effects of interference or cross-talk and therefore to increase the efficiency of the light module. It is therefore possible to reduce the dimensions of the light sources to reduce the albedo of the screen and improve its extinguished appearance.

[0071] In any event, the invention cannot be limited to the embodiments specifically described in this document, and extends in particular to any equivalent means and to any technically effective combination of these means. In particular, it may be possible to replace the printed circuit board with another support, such as a ceramic or glass substrate, rigid or flexible, straight or curved. It may also be possible to provide for the light sources to form an active matrix. It may also be possible to provide other types of light sources than that described, and in particular light sources of smaller dimensions, for example between 5 pm and 150 pm, such as micro-LEDs. It may also be possible to envisage materials other than those described.

Claims

Claims

1. Light module (1) of a signaling device of a motor vehicle, comprising a plurality of selectively controllable light sources (2); each light source comprising an elementary light generator and a photoluminescent element covering the elementary light generator and capable of absorbing light rays emitted by this generator and of emitting, in response, light rays of different wavelength, characterized in that each light source comprises a plurality of walls made of a white material, each wall coming into contact with a lateral surface of the photoluminescent element and the plurality of walls defining an enclosure framing the photoluminescent element of this light source.

2. Light module according to the preceding claim, characterized in that the elementary light generator of each light source is mounted on a support and in that each of the walls of said light source is mounted on this support and extends to an upper surface of the photoluminescent element.

3. Light module according to one of the preceding claims, characterized in that the light sources are encapsulated in the same layer of dark-colored material.

4. Light module according to the preceding claim, characterized in that the layer of dark-colored material has a transmission coefficient of between 50% and 95% over a thickness of 100 pm.

5. Light module according to one of claims 3 to 4, characterized in that the layer of dark-colored material comprises a polymer, in particular an epoxy or silicone resin, enriched with carbon particles or black pigments.

6. Light module according to the preceding claim, characterized in that the concentration of carbon particles, namely the mass of carbon relative to the mass of the polymer, is less than 0.05%.

7. Light module according to the preceding claim, characterized in that a portion of the layer of dark-colored material extends above the walls of white material and the photoluminescent elements of the light sources.

8. Light module according to one of the preceding claims, characterized in that it comprises a printed circuit board on which the elementary light generator of each light source is mounted, each generator comprising at least two electrical connection pads via which it is mounted and interconnected to said printed circuit board.

9. Light module according to one of claims 1 to 7, characterized in that it comprises a printed circuit board, in that each light source comprises a substrate, the elementary light generator of each light source comprising at least two electrical connection pads via which it is mounted on this substrate, and in that each light source is mounted and interconnected to said printed circuit board via its substrate.

10. Light module according to the preceding claim, characterized in that each wall of white material extends from the substrate and in that each substrate comprises two electrical connection pads via which it is mounted and interconnected to said printed circuit board, these pads each extending on a lower face of the substrate from a lateral edge of the substrate and each having a width such that these pads are separated by a space of at most 100 μm.

11. Light module (1) according to the preceding claim, in which the elementary light generator of each of the light sources (2) comprises at least one light-emitting semiconductor chip whose dimensions are between 100 pm and 400 pm.

12. Light module (1) according to one of the preceding claims, in which the elementary light generator of each of the light sources (2) comprises at least one light-emitting semiconductor chip whose dimensions are between 5 pm and 150 pm.

13. Light module (1), characterized in that it comprises a connector for receiving a control instruction from said plurality of light sources (2), in which the plurality of light sources forms a passive matrix and in which the controller (4) is arranged to control said passive matrix according to the control instruction received by the connector.

14. Signaling device for a motor vehicle, characterized in that it comprises a light module (1) according to one of the preceding claims, said plurality of light sources (2) forming a light screen of said signaling device.

15. A method of manufacturing a light source of a light module according to one of claims 1 to 10, the method comprising the following steps: a. Assembling at least one elementary light generator on a support; b. Depositing a layer of photoluminescent material on the elementary light generator; c. Cutting the photoluminescent material to form a photoluminescent element covering the elementary light generator; d. Deposition of a layer of white material on the photoluminescent element-elementary light generator assembly; e. Cutting of the white material to form a plurality of walls each coming into contact with a lateral surface of the photoluminescent element and defining an enclosure framing the photoluminescent element.

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