Light module for a motor vehicle signaling device

Abstract

The invention relates to a light-emitting module (1, 10, 100) for a motor vehicle signaling device, comprising a plurality of selectively controllable light sources (2), characterized in that the set of light sources (2) is mounted on a same common support (3), and in that the light-emitting module comprises a grid (4) overmolded on a base plate formed by or extending from the common support (3), the grid (4) being formed of an opaque material and extending on the base plate between each pair of light sources (2) so as to form a wall (41) separating adjacent light sources (2), so that each light source (2) emits a light beam into a cell (6) of the grid (4).

Description

[0001] This invention relates to the field of automotive lighting and light emission signal transmission. More specifically, this invention relates to the field of displays integrated into light-emitting vehicle lighting or light emission signal transmission modules.

[0002] In the field of automotive signal transmission, the known practice is to integrate displays, which can be made of an array of numerous light sources, into the vehicle's light-emitting modules (such as taillights).

[0003] The multiple light sources are typically selectively controllable and small enough to display information at an acceptable resolution on the display, which may take the form of messages or even pictographs.

[0004] The information provided by the display enables the improvement of signal transmission in motor vehicles by contextualizing or accompaniing a given signal transmission function.

[0005] To achieve a uniform appearance on a display, and especially to avoid pixels being perceived as noticeably separated (the so-called "spotting effect"), it is known to reduce the size of the light sources and the spacing between two adjacent light sources. Therefore, in addition to the resulting increase in display resolution, it is also possible to reduce the width of the area separating two adjacent pixels. Although this area appears dark, it becomes less noticeable as its width decreases.

[0006] However, it is impossible to reduce the spacing below a certain threshold without significantly increasing the production cost and complexity of the display.

[0007] In this context, to maintain a high resolution and uniform illumination (free from speckle effect) of the display, it is known to add a scattering element to the display. This scattering element scatters the light emitted by each light source to form pixels larger than the light source size, thus reducing the width of the area separating two adjacent pixels. Scattering must further ensure uniform brightness within each pixel and enable the display to achieve the desired quality in terms of sharpness and contrast.

[0008] However, reducing the spacing between adjacent light sources, combined with scattering the light emitted by the sources, can create parasitic effects between individual light sources, especially between adjacent ones. Specifically, if the spacing between the light sources is small, the light emitted by one source may spill into pixels generated by adjacent light sources.

[0009] This effect, also known as "crosstalk," reduces the resolution of a display. Specifically, pixels from adjacent light sources partially overlap and therefore can no longer be controlled independently of each other.

[0010] To meet these various constraints, it is known to equip the display with a grid, the walls of which define units that each house a light source. This allows for a reduction in the spacing between light sources, preservation of scattering elements, and avoidance of crosstalk, ensuring that light emitted by one light source is confined by the walls of the unit housing that light source, preventing it from spilling into adjacent pixels.

[0011] Nevertheless, the design and assembly challenges of the display still need to be addressed. Specifically, the reduced size of the light sources and the decreasing spacing between two adjacent light sources complicate the assembly of the grille with the light source array. In fact, considering the manufacturing tolerances of the grille and the light source array, as well as the differential expansion effect with temperature changes, some light sources may be located on the walls of the grille, or even outside their intended corresponding cells, during the assembly of the array and grille to form the display.

[0012] Therefore, there is a need to provide a vehicle light-emitting module designed to form a display with good resolution, no crosstalk, uniform illumination appearance (no spotting effect), and which can be assembled without any defects even if the size of the light source and the spacing between two adjacent light sources are reduced.

[0013] This invention falls within this context and aims to address these needs.

[0014] Therefore, one subject of the present invention is a light-emitting module for a signaling device of a motor vehicle, the light-emitting module comprising a plurality of selectively controllable light sources.

[0015] According to the invention, all light sources are mounted on the same common carrier, and the light-emitting module includes a grid overmolded onto a substrate formed or extending from the common carrier. The grid is formed of an opaque material and extends on the substrate between each pair of light sources to form walls separating adjacent light sources, such that each light source emits a light beam in a unit of the grid.

[0016] Therefore, this invention proposes to overmold the grille directly onto the carrier of the light source or onto a substrate extending from the common carrier. According to the solution described above, the fact that each light source is arranged in a unit of the grille makes it possible to form a housing in which the light emitted by the light source is contained or even reflected to reduce crosstalk. Thus, the size of the light source and the spacing between two adjacent light sources can be reduced, while elements are used to scatter the light emitted by each light source to avoid speckle effects. Furthermore, since the grille is made by overmolding, constraints on how the grille is positioned relative to the light source array during assembly due to variations in grille dimensions caused by manufacturing tolerances or thermal expansion are avoided.

[0017] Preferably, in this invention, the common carrier is a printed circuit board (PCB), on which all light sources are directly mounted.

[0018] A printed circuit board (PCB) has a first side and a second side opposite to the first side. A light source is mounted on the first side of the PCB, which faces the outside of the signal device, and a light-emitting module is integrated into the signal device.

[0019] In a preferred embodiment, the light sources can be arranged on a common carrier in such a way that they are separated from each other by a distance of less than 5 micrometers, but especially greater than 1 micrometer.

[0020] Here, "the distance between two light sources" refers to the distance separating one edge of one light source from the other edge of the other light source facing it.

[0021] Preferably, the light-emitting modules are arranged such that the fill factor of the pixels of the display is greater than 50%, preferably greater than 70%, or even greater than 80%. "Fill factor" refers to a given percentage of pixels whose brightness is greater than the maximum brightness of the pixel, particularly the ratio between the area of ​​10% of the pixels and the total area of ​​the pixels.

[0022] In this invention, the light source can be a light-emitting semiconductor chip. The semiconductor can be gallium nitride (GaN), which is capable of electroluminescence and emits blue light in response to a current passing through it. The photoluminescent element can be, for example, in the form of a resin comprising cerium-doped yttrium aluminum garnet (CE:YAG), capable of absorbing blue light and emitting yellow or white light in response to excitation by that light. The photoluminescent element is placed on the generator in such a way that some of the blue light excites the element, causing it to emit yellow or white light through photoluminescence. The remaining portion of the blue light passes through the element. Therefore, when powered, the light source simultaneously emits light with wavelengths in both the blue and yellow or white spectra, resulting in light that appears white to the human eye.

[0023] In one particular embodiment, the substrate is formed from a common carrier on which all light sources are mounted, and the grille is directly overmolded onto the common carrier.

[0024] In a preferred embodiment of the invention, the light-emitting module includes at least one electronic component mounted on a common carrier, the at least one electronic component being encapsulated within the wall of a grille.

[0025] Therefore, encapsulating the electronic components arranged on the common carrier using a molded overlay grid protects them from the risk of detachment and exposure to chemical corrosion. Furthermore, this feature frees up space typically occupied by such electronic components, allowing for the use of that space for other purposes or a reduction in the size of the light-emitting module. Finally, this feature improves the closed appearance of the display, as the electronic components are concealed within the wall.

[0026] In another embodiment, the substrate is formed of a first transparent material layer that encapsulates all light sources arranged on a common carrier, and the light-emitting module includes at least one electronic component encapsulated in the first transparent material layer.

[0027] Advantageously, the substrate is formed of a first transparent material layer that encapsulates all light sources arranged on a common carrier, such that each wall of the grille has a portion immersed in the first transparent material layer.

[0028] Advantageously, a first transparent material layer extends on the top surface of the light source and forms a groove between each pair of light sources, with each wall of the grille being overmolded in one of the grooves to extend on the top surface of the first transparent material layer.

[0029] In a preferred embodiment, the first transparent material layer is a transparent silicone resin or transparent silicone.

[0030] Preferably, the first transparent material layer has a thickness of less than 10 mm, or even 5 mm.

[0031] Advantageously, the first transparent material layer encapsulating the light source has a curved exit surface for the light beam at a position opposite to each light source, which forms the optical component of the light-emitting module.

[0032] Therefore, the existence of curved exit surfaces for the light beams at positions opposite to each light source enables the improvement of the sharpness of the light beams emitted from each of the light sources.

[0033] Preferably, the optical components of the light-emitting module can take the form of a lens or even a collimator.

[0034] In a particular embodiment of the invention, the first transparent material layer encapsulating the light source has an exit surface for the light beam that is provided with a scattering optical structure at a position opposite to each light source.

[0035] Preferably, the scattering optical structure can take the form of a specific pattern or even a Fresnel structure.

[0036] Advantageously, the light-emitting module includes at least one electronic component mounted on a common carrier, said at least one electronic component being encapsulated in a first transparent material layer.

[0037] In one embodiment of the invention, the walls of the grille are made of a white material.

[0038] The white material can be a dielectric material with a reflectance between 60% and 99%, and especially essentially equal to 90%. For example, the problem might lie with silicone resins rich in titanium dioxide (TiO2). In appropriate cases, each wall made of white material can have a thickness of up to 100 µm.

[0039] Therefore, these walls, on the one hand, allow light emitted by the light source to be intercepted, light that might otherwise reach another light source of the light-emitting module. Because of the white color of these walls, this light is reflected within the housing defined by the first wall, and the light source is located within this housing.

[0040] Therefore, these walls significantly reduce the effects of interference or crosstalk and improve the efficiency of the light-emitting module. Consequently, the size of the light source can be reduced without affecting the display resolution. Furthermore, the edges or thickness of these white walls contribute to the visible appearance of the light-emitting module when it is off, and thus reduce the influence of the color of the photoluminescent element on this off-center appearance.

[0041] In a preferred embodiment, the walls of the grille are made of a dark-colored material.

[0042] Due to the opacity and color of the dark material, the dark material further limits any interference or crosstalk that might have existed despite the presence of the white wall, thus improving the closed appearance of the light-emitting module.

[0043] Advantageously, the dark-colored material can be black or gray, and has a bulk transmittance between 50% and 95% for a thickness of 1 mm. Problems, for example, may lie with polymers rich in carbon particles or black pigments, particularly epoxy resins or silicones.

[0044] For example, it is conceivable that the carbon particle content (i.e., the mass of carbon divided by the mass of the polymer) is less than 0.05%. This characteristic is particularly suitable when the light-emitting module is intended to perform a controlled signal transmission function. Otherwise, it is conceivable that the carbon particle content is greater than 0.05%, especially for improving the contrast and appearance of the display when it is off.

[0045] Advantageously, the light-emitting module includes a second transparent material layer disposed between each wall of the grille, the second transparent material layer extending from the substrate to at least the height of the walls of the grille.

[0046] In a preferred embodiment, the second transparent material layer forms the emission surface of the light-emitting module and has an emission surface for the light beam with a scattering optical structure at a position opposite to each light source.

[0047] Preferably, the light-emitting module includes a mounted scattering supplementary layer extending on the grid. It may be proposed that the scattering supplementary layer be present regardless of whether the first transparent material layer is overmolded onto a common carrier or overmolded onto a substrate extending on the common carrier, and regardless of whether the scattering supplementary layer is directly supported by the grid and / or supported by a second scattering material layer.

[0048] In one particular embodiment, the scattering additional layer has a thickness significantly smaller than that of the transparent material layer.

[0049] Preferably, the scattering additional layer is made of a scattering material and / or a material including a scattering optical structure, which may, for example, be bonded to a transparent material layer.

[0050] Therefore, in another embodiment, the transparent material layer includes, for example, a plurality of scattering optical structures on its top surface.

[0051] Advantageously, the light-emitting module has a first protective layer placed between certain pairs of light sources and having a first albedo, and a second protective layer placed between other pairs of light sources and having a second albedo higher than the first albedo, the second layer defining the mark.

[0052] In one particular embodiment, the first protective layer is formed by molding on the grille, and the second protective layer is formed only on certain light sources by molding on the grille and the first protective layer.

[0053] Therefore, the second protective layer is molded and stacked on the first protective layer, thereby forming a specific pattern that can form a logo.

[0054] In this invention, "albedo" refers to the reflected power of a surface (also known as the surface reflectivity), expressed as a percentage that reflects the ratio between the reflected luminous flux and the incident luminous flux for a given incident luminous flux. In the remainder of this specification, albedo will refer to diffuse albedo, or even diffuse reflectivity.

[0055] In this invention, "mark" refers to any shape that can be recognized by the observer, especially a shape that contains one or more of the following elements: geometric figures, alphanumeric characters, patterns, and images of organisms.

[0056] It should be noted that most of the visible area of ​​a light-emitting display is not formed by the light sources themselves, but by the substrates on which these light sources are located. These substrates typically have a low-reflectivity protective layer (extending between the light sources) and thus largely contribute to the black-off appearance of the display. Therefore, a second protective layer is added to a portion of this first protective layer. This second protective layer has a higher reflectivity and is therefore able to scatter ambient light (such as beams of light emitted by city lighting or another vehicle) incident on the light-emitting display to a greater extent than the first layer.

[0057] Therefore, it should be understood that using this second protective layer, markings can be formed on the luminescent display both day and night without requiring power to the display. It will be noted that this second protective layer can be produced using a particularly simple manufacturing process.

[0058] Advantageously, the first protective layer can have a first albedo value substantially below 20%, particularly 15%, while the second protective layer can have a second albedo value above 50%, particularly 60%. As a variation, the light-emitting device may include a protective outer lens arranged uniformly with the light-emitting display and having an anti-reflective coating on one of its surfaces. Where appropriate, the first protective layer can have a first albedo value substantially below 15%, particularly 10%, while the second protective layer can have a second albedo value above 20%, particularly 30%. Specifically, using such a protective outer lens allows for increased contrast between the first and second layers or allows for maintaining the same contrast between the two layers, with the aim of reducing the difference in albedo, which in particular allows for a reduction in the cost of manufacturing the light-emitting device.

[0059] In a preferred embodiment, each of these light sources includes at least one light-emitting semiconductor chip with a size between 100 micrometers and 400 micrometers.

[0060] This type of chip is particularly known as a miniature LED. Where appropriate, the light sources can be arranged on the same common carrier in such a way that the distance between the centers of two adjacent light sources is less than 1 millimeter.

[0061] In one particular embodiment, each of these light sources includes at least one light-emitting semiconductor chip with a size between 5 micrometers and 150 micrometers.

[0062] This type of chip is specifically referred to as a micro LED. In appropriate cases, the light sources can be arranged on the same common carrier in such a way that the distance between the centers of two adjacent light sources is between 200 μm and 400 μm, or even less than or equal to 300 μm.

[0063] Preferably, the light-emitting module includes a connector for receiving control commands to control the plurality of light sources and at least one controller capable of selectively controlling the light sources, the plurality of light sources forming a passive matrix, and the controller being arranged to control the passive matrix depending on the control commands received via the connector.

[0064] Advantageously, the light-emitting module includes a connector for receiving control commands to control the plurality of light sources and at least one controller capable of selectively controlling the light sources. Where appropriate, the plurality of light sources form a passive matrix, and the controller is arranged to control the passive matrix depending on the control commands received via the connector. For example, the light-emitting module may include a plurality of drivers for controlling the electrical power supplied to the light sources, each driver mounted on a first side of a printed circuit board perpendicular to one of the light sources, with an eye toward controlling the electrical power supplied to the light source, which in particular depends on commands received from the controller associated with that light source.

[0065] Advantageously, the light-emitting module includes at least 500 light sources (especially distributed in a two-dimensional array), and the controller is arranged to selectively control each of these light sources.

[0066] Advantageously, the light-emitting module includes an interconnect system connected to a controller and arranged to interconnect the controller with multiple light sources. The interconnect system can be integrated into a printed circuit board or can be a separate component mounted on the printed circuit board. The interconnect system can include connector arrays, such as ball grid arrays (BGAs) or area grid arrays (LGAs).

[0067] Multiple light sources form a passive matrix, wherein each row and column of light sources is associated with a driver mounted perpendicularly to that row or column on a PCB for controlling the electrical power supplied to that row or column of light source. Therefore, a controller is arranged to control each of the sources in the passive matrix in such a manner that it depends on control commands received via a connector: sequentially scanning the rows of the matrix, then scanning the columns, to control the electrical power supplied to each of the light sources.

[0068] In one particular embodiment, the walls of the grid are arranged such that each cell has a truncated conical shape.

[0069] Accordingly, the walls of the grille have a specific inclined shape, making it easier to demold the walls of the grille, again with an emphasis on facilitating the production of such a light-emitting module according to the invention. The walls of the grille are particularly arranged such that their cross-section in a plane perpendicular to the common carrier has a rectangular shape.

[0070] Another subject of the present invention is a signaling device for motor vehicles, characterized in that the signaling device includes a light-emitting module according to the present invention, wherein the plurality of light sources form a light-emitting display of the signaling device.

[0071] Another subject of the present invention is a method for manufacturing a light-emitting module according to the present invention, the method comprising the following steps: Connect multiple light sources to the same shared carrier; An opaque material is overmolded onto a common carrier to form a grid, which is arranged between each pair of light sources.

[0072] In another embodiment, the manufacturing method includes the following steps: Connect multiple light sources to the same shared carrier; A first transparent material layer is deposited on a common carrier to encapsulate the plurality of light sources; The transparent material layer is cut to form multiple grooves, each groove extending between a pair of adjacent light sources; An opaque material is wrapped around each groove to form a grid within the groove.

[0073] Preferably, the manufacturing method further includes the step of forming a second transparent material layer between each wall of the grille.

[0074] In one particular embodiment, the manufacturing method further includes the step of depositing a scattering additional layer on top of the grid.

[0075] In a preferred embodiment, the scattering additional layer is a scattering film adhered to the top surface of the wall of the grid and / or the top surface of the second transparent material layer.

[0076] The invention will now be described using examples and with reference to the accompanying drawings. These examples are merely illustrative and are in no way intended to limit the scope of the invention. In the drawings, the figures illustrate: [ Figure 1 A front view of a light-emitting module according to an embodiment of the present invention is shown schematically and in part. [ Figure 2 [Illustratively and partially showing] Figure 1 A cross-sectional view of the light-emitting module; [ Figure 3 A side view of a light-emitting module according to another embodiment is shown schematically and in part. [ Figure 4 A side view of a light-emitting module according to yet another embodiment is shown schematically and in part.

[0077] In the following description, unless otherwise stated, elements that are identical in structure or function and appear in the various figures are labeled with the same reference numerals.

[0078] [ Figure 1 The image shows a front view of a light-emitting module 1 according to an embodiment of the present invention, and [ Figure 2 The image shows a cross-sectional view of the light-emitting module 1. In the described example, the light-emitting module 1 is intended to be integrated into the headlight or taillight of a motor vehicle, and the light-emitting module 1 forms a display.

[0079] The light-emitting module 1 includes multiple light sources 2 mounted on the same common carrier 3, which in the described example is formed from a printed circuit board.

[0080] In the described example, the light-emitting module 1 includes more than 20,000 light sources 2, arranged in a passive matrix of 256 columns and 80 rows. The light sources 2 are miniature LEDs with dimensions between 100 µm and 400 µm. The light sources 2 are spaced apart from each other with a center-to-center distance of less than or equal to 1 mm. It should be noted that other sizes of light sources 2, other distances between light sources 2, other numbers of light sources 2, or even other distributions of light sources 2 are contemplated without departing from the scope of the invention.

[0081] Each light source 2 includes a light-emitting semiconductor chip 2a, which forms a basic light generator. The semiconductor can be, for example, gallium nitride or GaN, capable of electroluminescence and emitting blue light in response to an electric current flowing through it, the spectrum of which, for example, has a peak centered between wavelengths of 410 nm and 480 nm. Each light source 2 also includes a photoluminescent element 2b that encapsulates the chip 2a. The photoluminescent element can be, for example, in the form of a resin comprising cerium-doped yttrium aluminum garnet (CE:YAG), capable of absorbing blue light and emitting yellow or white light in response to excitation by the light.

[0082] The printed circuit board or PCB 3 has a first side 31 and a second side 32 opposite to the first side 31. The light source 2 is mounted on the first side 31 of the PCB, which faces the outside of the signal device, and the light-emitting module 1 is integrated into the signal device.

[0083] It should be noted that in the described example, the printed circuit board is a so-called multilayer PCB, comprising a stack of layers between a first side and a second side. These layers are specifically designed for interconnection of components mounted on the PCB and may each include multiple through-holes, blind vias, or buried vias arranged in the PCB to connect to various interconnect layers. These vias open to the first or second side of the PCB and are flush with the metal plane to which they are connected.

[0084] like[ Figure 2As shown, all light sources 2 are encapsulated within a transparent material layer 5. In the described example, the transparent material layer 5 is formed of transparent silicone resin, which is deposited on the PCB 3 to a thickness of less than 10 mm. Furthermore, it can be proposed that the transparent material layer 5 also encapsulates other electronic components of the light-emitting module 1, which will be mounted on the first side 31.

[0085] In addition, the transparent material layer 5 encapsulating the light source 2 has a curved emitting surface 7 for the light beam at a position opposite to each light source 2, which forms the optical component of the light-emitting module 1.

[0086] Considering the materials and structure used, and especially the curved shape 7, the material layer 5 thus helps to scatter the light emitted by the light sources 2 to form pixels with a size significantly larger than that of the light sources 2. Combined with the reduction of the spacing p separating two adjacent light sources 2, this layer makes it possible to increase the fill factor of the pixels formed by the light sources 2. Therefore, the speckle effect can be avoided, i.e., the display formed by the module 1 can be prevented from having a speckled appearance when lit, and the width of the area separating two adjacent pixels is significantly smaller.

[0087] As a variation, it can be proposed that the first transparent material layer 5 has an exit surface with a scattering optical structure (such as a Fresnel structure) at a position opposite to each light source.

[0088] exist[ Figure 1 ]and[ Figure 2 In one embodiment, a transparent material layer 5 forms a substrate on which a grid 4 is formed.

[0089] The grille 4 includes a plurality of walls 41 arranged in a two-dimensional array to define a unit 6 for each of the light sources 2. Each wall 41 is overmolded in a groove 51 pre-formed in the top surface of the transparent material layer 5, such that the wall has a portion immersed in the transparent material layer 5 and extends to a height of about 1 mm above the layer 5.

[0090] Furthermore, to facilitate the demolding of the grille 4 onto the transparent material layer 5, the walls 41 of the grille 4 are arranged such that each unit 6 has a truncated conical shape that narrows toward the transparent material layer 5. In particular, it can be seen that the walls 41 of the grille 4 are arranged such that their cross-section in the plane perpendicular to the common carrier 3 has a rectangular shape.

[0091] Therefore, the grating 4 extends from the transparent material layer between each pair of light sources 2, and each light source 2 thus emits a beam of light into a cell 6 of this grating 4.

[0092] The grid is made of a dark-colored (e.g., black or gray) opaque material, with a transmittance between 50% and 95% when it is 1 mm thick. Problems, for example, might arise with polymers rich in carbon particles, and especially with silicone, where the carbon particle content is less than 0.05%.

[0093] Therefore, each wall 41 of unit 6 is capable of intercepting light emitted by the light source 2 housed in that unit, light that would otherwise be directed toward adjacent units 6 and superimposed on the light emitted by the light source 2 housed in the adjacent unit. By intercepting these parasitic light rays, wall 41 thus reduces crosstalk and thus helps to improve the resolution, sharpness, and contrast of the display formed by the light-emitting module 1.

[0094] In addition, the light-emitting module 1 includes a scattering auxiliary layer 12 extending on the grille 4. This auxiliary layer further enhances the uniformity of the illuminated appearance of the display.

[0095] Advantageously, the light-emitting module 1 includes a connector (not shown) for receiving control commands to control the plurality of light sources 2 and at least one controller (not shown) capable of selectively controlling the light sources 2. Where appropriate, the plurality of light sources 2 form a passive matrix, and the controller is arranged to control the passive matrix depending on the control commands received via the connector. For example, the light-emitting module 1 may include a plurality of drivers for controlling the electrical power supplied to the light sources 2, each driver mounted on a first side 31 perpendicular to one of the light sources on a printed circuit board 3 and encapsulated in a layer 5, to control the electrical power supplied to the light source, which in particular depends on commands received from the controller associated with that light source.

[0096] It is conceivable that a single controller controls all the light sources 2 mounted on the PCB, or multiple controllers can be set up, each of which selectively controls a matrix (e.g., 64 × 64 (i.e., 4096) light sources 2).

[0097] The instruction can be, for example, sent by the vehicle's computer or signaling device, with an aim of displaying signs, messages, patterns, or pictographs.

[0098] For example, the instruction could be a pictogram to notify an outside observer that a vehicle's door is open, a pictogram to notify a driver following the vehicle that there is black ice on the road, or even an instruction to display traffic-related information.

[0099] Therefore, multiple light sources 2 form a passive matrix, wherein each row and column of light source 2 is associated with a driver (not shown), which is mounted perpendicularly to that row or column on the PCB for controlling the electrical power supplied to the light source 2 in that row or column. Thus, a controller is arranged to control each of the sources in the passive matrix in such a manner that it depends on control commands received via a connector: sequentially scanning the rows of the matrix, then scanning the columns, to control the electrical power supplied to each of the light sources 2.

[0100] The method for manufacturing according to [[] will now be described. Figure 1 ]and[ Figure 2 An example of the method of the light-emitting module 1 in the embodiment of the present invention.

[0101] In the first step, multiple light sources 2 are connected to the same PCB 3. A transparent material layer 5 (such as transparent silicone resin) is deposited on a common carrier 3 to encapsulate the multiple light sources 2. The layer 5 can be shaped to form a curved shape of surface 7.

[0102] In the second step, grooves 51 are formed in the transparent material layer 5 by means of a blade, each groove extending between a pair of adjacent light sources 2.

[0103] In the third step, the wall 41 is overmolded into each of the grooves 51 in the transparent material layer 5 to form a grid 4 defining units, each of which accommodates a light source 2.

[0104] Since the grid 4 is made by overmolding, the constraints on how the grid 4 is positioned relative to the light source 2 array can be overcome compared to the method used to assemble a pre-designed grid with the light source 2 array (in which the grid size variation caused by manufacturing tolerances or thermal expansion during assembly can cause defects in the positioning of some walls 41 relative to the source 2).

[0105] Finally, in the fourth step, a scattering film is deposited on the top surface of wall 41 to form a scattering additional layer 12.

[0106] Now refer to [ Figure 3 Another embodiment of the invention will now be described. Figure 3 The image shows a cross-sectional view of the light-emitting module 10 according to this other embodiment. In this example, a printed circuit board 3 on which the light source 2 is mounted forms a substrate, and the grille 4 is directly overmolded onto the substrate. In other words, the light-emitting module 10 does not have a transparent material layer that directly encapsulates the light source 2.

[0107] Therefore, the grille 4 is directly overmolded onto the first side 31 of the PCB 3. The grille 4 extends from the PCB 3 between each pair of light sources 2 to form walls 41 separating adjacent light sources 2, thereby defining a unit 6 that accommodates one light source 2. Thus, each light source 2 emits a light beam in one unit 6 of the grille 4.

[0108] In the described example, the grille is made of a white material with a reflectance between 60% and 99%, specifically essentially equal to 90%. For example, a problem might arise with titanium dioxide (TiO2)-rich silicone resin. Where appropriate, each wall 41 can have a thickness of up to 100 μm. Because of this white color, light emitted by the light source 2 is reflected within the housing 6 defined by the walls 41, where the light source 2 is located. Therefore, these walls significantly reduce the effects of interference or crosstalk and improve the efficiency of the light-emitting module 10. Thus, the size of the light source can be reduced without affecting the resolution of the display. Furthermore, the edge surfaces or thickness of these white walls contribute to the visible appearance of the light-emitting module when it is off, and thus reduce the influence of the color of the photoluminescent element on this off appearance.

[0109] Electronic components 8 are also mounted on PCB 3. During the overmolding of the grille onto PCB 3, these components are individually or in groups encapsulated within the walls 41 of the grille 4 to reduce the risk of exposure, wear, and detachment of the electronic components 8, thereby shielding these components 8 and releasing the back side 32 of the PCB, on which the components 8 are conventionally mounted. Components 8 may be active or passive components, connected via PCB 3 to the power supply and / or control unit of the light-emitting module to participate in supplying power to the light source 2 and / or controlling the light source.

[0110] Compared to the method used to manufacture the light-emitting module 1 of the first embodiment, the light-emitting module 10 can be manufactured in fewer steps because the wall 41 of the grille 4 can be directly overmolded onto the PCB 3.

[0111] Now refer to [ Figure 4 The third embodiment of the present invention will now be described. Figure 4 The image shows a cross-sectional view of the light-emitting module 100 according to the third embodiment.

[0112] [ Figure 4 The embodiments of ] and [ Figure 1 ]and[ Figure 2 The embodiments are basically the same, with the grille 4 being overmolded in a groove 51 in a transparent material layer 5.

[0113] In contrast, the first material layer 5 lacks the optical element 7, and the second transparent material layer 11 has been overmolded onto the transparent material layer 5, between each wall 41 of the grille 4. Therefore, the second transparent material layer 11 extends from the first transparent material layer 5 to the height of the wall 41 of the grille 4. The material of the second layer 11 can be the same as the material of the first transparent material layer 5, or conversely, a different material, especially one with scattering properties.

[0114] In the described example, the top side of the second transparent material layer 11 forms the emission surface of the light-emitting module 1, and has a scattering optical structure 11a at a position opposite to each light source 2. Alternatively or additionally, it may be proposed to deposit a scattering film on the top surface of the second layer 11 to form a scattering optical structure 11a with […]. Figure 1 ]and[ Figure 2 The same scattering additional layer as layer 12 in the embodiment of the example.

[0115] Therefore, the light-emitting module 100 can be made using a method substantially the same as that used to manufacture the light-emitting module 1, with the step of depositing a scattering film following or replaced by the following steps: the step of molding a transparent material onto the first layer 5 and between the walls 41 to form a second layer 11, and the step of optionally modifying or texturing the top surface of the second layer 11 to form a scattering optical structure 11a.

[0116] The above description clearly explains how the present invention enables the achievement of its intended purpose, namely, to provide a light-emitting module that can form a display with good resolution, no crosstalk, a uniform illumination appearance (no spotting effect), and that the vehicle light-emitting module can be assembled without any defects even if the size of the light source and the spacing between two adjacent light sources are reduced.

[0117] Therefore, it should be understood that these objectives are achieved, in particular, by directly overmolding an opaque grille onto the carrier of the light source or onto a substrate extending from that carrier. This grille defines units, each housing a light source and each intercepting light that could potentially interfere with pixels formed by adjacent light sources. Thus, the grille can limit crosstalk effects and thereby allows for a reduction in the size of the light source and the spacing between two adjacent light sources, while using elements to scatter the light emitted by each light source to avoid speckle effects. Furthermore, since the grille is overmolded, constraints on how the grille is positioned relative to the light source array during assembly are avoided due to variations in grille dimensions that could be caused by manufacturing tolerances or thermal expansion.

[0118] In any event, the invention is not limited to the embodiments specifically described herein, but extends particularly to any equivalent means and any technically feasible combination thereof. In particular, it may be proposed to replace the printed circuit board with another carrier (e.g., a rigid or flexible, straight or curved ceramic or glass substrate). It may also be proposed that the light source 2 form an active matrix. Other types of light sources 2 besides those described may also be used, and especially smaller light sources 2 (e.g., between 5 μm and 150 μm), such as micro-LEDs. It is also conceivable to use materials other than those described, or even to interchange the various materials of the already described embodiments, particularly to indiscriminately create gray, white, or black walls, or even to achieve alternation or variation of wall hues in a given embodiment.

Claims

1. A light-emitting module (1, 10, 100) for a signal device of a motor vehicle, the light-emitting module comprising a plurality of selectively controllable light sources (2), characterized in that, All the light sources (2) are mounted on the same common carrier (3), and wherein the light-emitting module includes a grid (4) which is overmolded onto a substrate formed by or extending from the common carrier (3), the grid (4) being formed of an opaque material and extending on the substrate between each pair of light sources (2) to form a wall (41) separating adjacent light sources (2), such that each light source (2) emits a light beam in a unit (6) of the grid (4).

2. The light-emitting module (10) as described in the preceding claim, characterized in that, The substrate is formed from the common carrier (3) on which all the light sources (2) are mounted, and the grille (4) is directly overmolded onto the common carrier (3).

3. The light-emitting module (10) as described in the preceding claim, characterized in that, The light-emitting module includes at least one electronic component (8) mounted on the common carrier (8), and the at least one electronic component (8) is encapsulated in the wall (41) of the grille (4).

4. The light-emitting module (1, 100) as described in claim 1, characterized in that, The substrate is formed of a first transparent material layer (5) which encapsulates all the light sources (2) arranged on the common carrier (3) such that each wall (41) of the grille (4) has a portion immersed in the first transparent material layer (5).

5. The light-emitting module (1) as described in the preceding claim, characterized in that, The first transparent material layer (5) encapsulating the light source (2) has a curved emitting surface (7) for the light beam at a position opposite to each light source (2), the emitting surface forming an optical component of the light-emitting module (1).

6. The light-emitting module (1) as described in any one of claims 4 and 5, characterized in that, The first transparent material layer (5) encapsulating the light source (2) has an exit surface (7) for the light beam with a scattering optical structure at a position opposite to each light source (2).

7. The light-emitting module (100) as described in claim 4, characterized in that, The light-emitting module includes a second transparent material layer (11) disposed between each wall (41) of the grille (4), the second transparent material layer extending from the substrate (5) to at least the height of the wall (41) of the grille (4).

8. The light-emitting module (100) as described in the preceding claim, characterized in that, The second transparent material layer (11) forms the emission surface of the light-emitting module (100) and has an emission surface for the light beam provided with a scattering optical structure (11a) at a position opposite to each light source (2).

9. The light-emitting module (1, 10, 100) as described in any of the preceding claims, characterized in that, The light-emitting module includes a scattering additional layer (12) extending on the grille (4).

10. The light-emitting module (1, 10, 100) as described in any one of the preceding claims, characterized in that, The walls (41) of the grid (4) are arranged such that each unit has a truncated conical shape.

11. The light-emitting module (1, 10, 100) as described in any of the preceding claims, characterized in that, The light-emitting module has a first protective layer placed between certain pairs of light sources (2) and having a first albedo, and a second protective layer placed between other pairs of light sources (2) and having a second albedo higher than the first albedo, the second layer defining a mark.

12. A method for manufacturing a light-emitting module (10) as claimed in claims 1 to 3 and as dependent on claims 2 or 3, according to any one of claims 9 to 11, characterized in that, The method includes the following steps: a. Connect multiple light sources (2) to the same common carrier (3); b. Overmolding an opaque material onto the common carrier (3) to form the grille (4), the grille (4) being arranged between each pair of light sources (2).

13. A method for manufacturing a light-emitting module (1, 100) as described in any one of claims 4 to 11, characterized in that, The method includes the following steps: a. Connect multiple light sources (2) to the same common carrier (3); b. Deposit a first transparent material layer (5) on the common carrier (3) to encapsulate the plurality of light sources (2); c. Cut the first transparent material layer (5) to form a plurality of grooves, each groove extending between a pair of adjacent light sources (2); d. Cover each groove with a molded opaque material to form the grille (4) in the groove.

14. The method as described in the preceding claim, characterized in that, The method includes the step of forming a second transparent material layer (11) between each wall (41) of the grille (4).

15. The method according to any one of claims 12 to 14, characterized in that, The method includes the step of depositing a scattering additional layer (12) on top of the grid (4).

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