Automotive lighting devices

Abstract

A light-emitting device comprising an optical device and a first printed circuit board, on which a light source is fixed, the light source comprising a light-emitting zone and a protective housing surrounding the light-emitting zone, and a first height of the protective housing relative to a flat surface of the first printed circuit board is greater than a second height of the light-emitting zone, the light-emitting device further comprising a mask arranged between the optical device and the light-emitting zone so as to prevent light rays coming from the light-emitting zone from being reflected on the protective housing and reaching the optical device, the mask being in direct contact with the first printed circuit board and / or in direct contact with the light source.

Description

[Technical Field]

[0001] The present invention relates to a light emitting device for an automobile. [Background technology]

[0002] Today, automotive optical systems are equipped with ultra-pixelated LED-based light sources that enable a wide variety of images to be displayed. However, there are various challenges in using such light sources in vehicle optical systems.

[0003] Firstly, the clarity of the image projected by the light source may be adversely affected by the phenomenon that light rays coming from the light ray emitting zone are reflected on elements located in the optical system and close to the light ray emitting zone. In particular, light reflections may be caused by reflective surfaces of the protective housing, which overlie the light ray emitting zone of the light source.

[0004] Additionally, the operation of the light source may be disrupted by external electromagnetic fields generated by electronic components located near the light source.

[0005] Additionally, light sources generate heat that must be removed to avoid damaging electronic components located within or near the light source.

[0006] Additionally, there is a need to protect the components of the optical system from the destructive nature of sunlight that is transmitted through the lenses of the optical system. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide a light-emitting device that makes it possible to overcome the above-mentioned limitations. In particular, the present invention makes it possible to produce a simple and reliable light-emitting device that is simultaneously able to filter light reflections on a protective housing that bounds the light-emitting zone of the light-emitting device, to protect the light-emitting device from solar radiation and ambient electromagnetic fields, and to dissipate the heat generated by the light-emitting zone. [Means for solving the problem]

[0008] To this end, the invention provides a light-emitting device comprising an optical device and a first printed circuit board, on which a light source is fixed, comprising a light-emitting zone and a protective housing surrounding said light-emitting zone, wherein a first height of the protective housing relative to a flat surface of the first printed circuit board, measured in a first direction perpendicular to said flat surface and directed towards the optical device, is greater than a second height of the light-emitting zone relative to the flat surface, measured in the first direction; the light emitting device comprises a mask disposed between the optical device and the light emitting zone so as to prevent light rays coming from the light emitting zone from being reflected on the protective housing and reaching the optical device; The mask is in direct contact with the first printed circuit board and / or in direct contact with the light source.

[0009] In one embodiment, the mask directly abuts the radiation emission zone and / or the protective housing of the light source.

[0010] In one embodiment, the mask comprises an opening extending along the major surface and defined by an inner edge for passing light rays generated by the light emitting zone, the inner edge protruding from or being continuous with the major surface.

[0011] In one embodiment, the edge of the inner edge of the mask has a chamfer, for example a 45 degree chamfer, directed towards the light emission zone.

[0012] In one embodiment, the inner edge of the mask protrudes from the major surface of the mask, and an end of the inner edge directly abuts the light emission zone so as to bound the periphery of the light emission zone.

[0013] In one embodiment, the mask directly abuts a heat sink located near the light emitting element, thereby facilitating cooling of the light emitting zone.

[0014] In one embodiment, the mask is made from a flexible material that allows the inner edge to conform to the shape of the light emission zone.

[0015] In one embodiment, the inner edge of the mask is continuous with the major surface of the mask, with a portion of the major surface of the mask directly abutting the protective housing.

[0016] In one embodiment, the mask is made of metal, particularly aluminum or stainless steel.

[0017] In one embodiment, the mask forms a Faraday cage within which the light source is placed.

[0018] The accompanying drawings show, by way of example, one embodiment of a light-emitting device according to the invention. [Brief explanation of the drawings]

[0019] [Figure 1] 1A and 1B illustrate a schematic diagram of an embodiment of a light-emitting device according to the present invention. [Figure 2] 1 is a cross-sectional view showing a schematic representation of a printed circuit board with a light emission zone and a protective housing fixed thereto; [Figure 3] FIG. 1 illustrates an embodiment of a light source. [Figure 4] 1 is a top view illustrating a first embodiment of a light-emitting device according to the present invention. [Figure 5] 1 is a cross-sectional view showing a first embodiment of a light-emitting device according to the present invention. [Figure 6] FIG. 2 is a cross-sectional view showing a second embodiment of a light-emitting device according to the present invention. [Figure 7] FIG. 4 is a cross-sectional view showing a third embodiment of a light-emitting device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] A first embodiment of a light emitting device according to the present invention is shown in FIG.

[0021] The light emitting device 10 mainly includes: a light source 1 comprising a light emission zone 11 and a protective housing 12 surrounding the light emission zone 11; a first printed circuit board 2 having a surface 21 on which a light emission zone 11 and a protective housing 12 are fixed; an optical device 3, which may for example be a lens; a mask 4 arranged between the light emission zone 11 and the optical device 3; Equipped with.

[0022] Preferably, the light source 1 is an LED, the structure of which is shown in detail in FIGS.

[0023] FIG. 2 presents a first schematic view of a light emitting zone 11 surrounded by a protective resin 12 .

[0024] The light-emitting zone 11 is divided into a first zone 111, called the active zone, which contains a photon-emitting material, and a second zone 112, called the technical zone, which does not contain a photon-emitting material.

[0025] The active zone 111 comprises a material that emits photons when a current passes through it, thus producing blue light. The active zone 111 also comprises a phosphor layer that converts the blue light into white light.

[0026] The active zone 111 is also called a "matrix of pixels." The photon-emitting material is divided into a number of pixels. Each pixel can be individually controlled to emit photons. Each pixel of the matrix 111 can emit light over 180 degrees. In one embodiment, the matrix of pixels 111 may comprise 25,000 pixels.

[0027] The technical zone 112 is disposed around the active zone 111. In other words, the technical zone 112 is a thin strip that bounds the periphery of the active zone 111 and does not emit any light. The width of the technical zone 112 is on the order of magnitude of 500 microns, or alternatively 300 microns.

[0028] In a preferred embodiment, the protective housing 12 is a protective resin 12 molded around the technical zone 112 .

[0029] In the remainder of this document, the terms "protective housing" and "protective resin" are used interchangeably.

[0030] On the flat surface 21 of the first printed circuit board 2, a light emitting zone 11 and a protective resin 12 are fixed.

[0031] A first direction d1 is defined that is perpendicular to the flat surface 21 of the first printed circuit board 2, and that is directed towards the optical device 3.

[0032] In the above-described embodiment, the first height h1 of the protective resin 12 relative to the flat surface 21, measured in the first direction d1, is greater than the second height h2 of the light emitting zone 11 relative to the flat surface 21, measured in the first direction d1. In other words, the height h1 of the protective resin 12 exceeds the height h2 of the light emitting zone 11. For example, the height h1 is greater than the height h2, and the difference Δh between the two heights can be, for example, 0.2 mm to 0.3 mm.

[0033] 3 shows a schematic representation of a light source 1 or LED 1 comprising the above-mentioned light emitting zone 11 and protective resin 12. In this more detailed view, the structure of the LED 1 is shown more precisely. In particular, the matrix of pixels 111 is shown in relation to the matrix of switches 13.

[0034] The LED 1 also comprises a second printed circuit board 14 intended to control the matrix of switches 13. The assembly formed by the matrix of pixels 111 and the matrix of switches 13 is fixed to the second printed circuit board 14, for example by soldering.

[0035] The second printed circuit board 14 allows for independent control of the on or off state of each pixel of the LED 1. A network of wired connections 15 allows for control of each pixel. The wired connections 15 are arranged between the emission surface 11 and the second printed circuit board 14.

[0036] The protective resin 12 serves to protect the network of wired connections 15. For this purpose, the protective resin 12 completely encapsulates the network of wired connections 15. The height difference Δh between the emission surface 11 and the protective resin 12 is therefore due to the volume occupied by the network of wired connections 15 and the excess thickness of resin required to encapsulate the ends of the wired connections 15 connected to the emission surface 11.

[0037] Furthermore, for better thermal insulation of the network of wired connections, the color of the protective resin is preferably light so as not to absorb heat.

[0038] The excessive thickness and light reflecting ability of the protective resin 12 contribute to the occurrence of parasitic light reflection within the LED 1.

[0039] In order to counteract parasitic light reflections, the light emitting device 10 comprises a mask 4 arranged between the optical device 3 and the light emitting zone 11. The mask 4 serves to prevent light rays coming from the light emitting zone 11 and reflected on the protective resin 12 from reaching the optical device 3.

[0040] In other words, the mask 4 is integrated into the light emitting device 10 and blocks the light reflection caused by the excess thickness Δh of the protective resin 12 relative to the light emitting zone 11 before it reaches the optical device 3 .

[0041] In the absence of the mask 4, the light emitting zone 11 bounded by the protective resin 12 defines a first light beam 20 shown in Figures 5 to 7. The first light beam 20 corresponds to a light ray emitted by the light emitting zone 11 and reaching the optical device 3 without reflecting on the protective resin 12.

[0042] The mask 4 provided on the light-emitting device 10 extends along the main surface 41 and has an opening 42 defined by an inner edge 43, which allows the passage of light rays generated by the light emission zone 11 to the optical device 3.

[0043] In the presence of the mask 4, the light emitting zone 11 then defines a second light beam 30 corresponding to the light rays emitted by the light emitting zone 11 that reach the optical device 3 after passing through the mask 4. Depending on the shape of the opening 42, the light beam 20 may have various shapes, for example a conical shape if the opening 42 is circular.

[0044] Advantageously, the shape of the opening 42 is defined so that the second light beam 30 is substantially identical to the first light beam 20 and filters out light rays resulting from reflection on the protective resin 12 .

[0045] The end 431 of the inner edge 43 of the mask has a chamfer 432, for example a 45 degree chamfer, directed towards the light emission zone 11. The chamfer has the effect of preventing light rays coming from the emission zone 11 from reflecting on the end 431 of the inner edge 43.

[0046] The main face 41 is preferably parallel to the surface of the light emission zone 11 .

[0047] Advantageously, the mask 4 is made of a light-absorbing material, in particular the mask 4 is made of a dark material. This feature of the mask 4 has the first effect of preventing reflection on the mask 4 of light rays coming from the emission zone 11. It also has the effect of protecting the light-emitting device 10 from the destructive effects of sunlight that penetrates into the light-emitting device 10 through the optical device 3.

[0048] Various embodiments of the mask 4 are described below with reference to Figures 4 to 7. Depending on the embodiment, the mask 4 abuts directly against the first printed circuit board 2 and / or directly against the light source 1. When abutting against the light source 1, the mask 4 may also abut directly against the light emission zone 11 and / or the protective housing 12.

[0049] therefore, In the first embodiment illustrated by FIGS. 4 and 5, the mask 4 abuts against the emission surface 11 forming part of the LED 1, which itself is fixed to a first printed circuit board 2; In the second embodiment illustrated by FIG. 6, the mask 4 abuts against a protective resin 12 that forms part of the LED 1, which itself is fixed to a first printed circuit board 2; In the third embodiment illustrated by FIG. 7, the mask 4 abuts against the first printed circuit board 2 .

[0050] In the first embodiment, the inner edge 43 of the mask 4 protrudes from the main surface 41 , while in the second and third embodiments, the inner edge 43 of the mask 4 is continuous with the main surface 41 .

[0051] 4 and 5 show respectively a top view and a cross-sectional view of a first embodiment of a light-emitting device 10 according to the present invention.

[0052] In the first embodiment, the inner edge 43 of the mask 4 is substantially perpendicular to the main surface 41 of the mask 4 and is directed towards the radiation emission zone 11. An end 431 of the inner edge 43 abuts the radiation emission zone 11 so as to bound the periphery of the radiation emission zone 11. Advantageously, the contact between the end 431 and the radiation emission zone 11 is made near the technical zone 112 of the radiation emission zone 11.

[0053] Advantageously, in the first embodiment, the chamfer 432 is oriented facing both the light emitting zone 11 and the protective resin 12 .

[0054] Advantageously, the mask 4 is made of a flexible material that allows the inner edge 43 to conform to the shape of the light emission zone 11, in particular allowing the end 431 of the inner edge 43 to be in contact with the emission zone 11 and at the same time being as close as possible to the technical zone 112. Furthermore, the mask 4 may have cutouts 44 that make it easier to adapt the inner edge 43 to the shape of the light emission zone 11. Adapting the inner edge 43 to the shape of the emission zone may require overlapping at the boundaries of the cutouts 44, in which case, in at least one cutout 44, a first boundary of the cutout overlaps a second boundary of the cutout.

[0055] 6, the inner edge 43 of the mask 4 is continuous with the main surface 41 of the mask 4, and a portion 411 of the main surface of the mask directly abuts the protective resin 12. As a result of their shape and of their material which absorbs light rays, the inner edge of the mask 4 blocks the light rays coming from the emission zone 11 which are reflected on the protective resin 12, in particular as a result of the edge 431 and the chamfer 432.

[0056] In the third embodiment shown in Figure 7, the inner edge 43 of the mask 4 is continuous with the main surface 41 of the mask 4, and the mask 4 abuts directly on the first printed circuit board 2 (the connection between the mask 4 and the first printed circuit board 2 is not shown in Figure 7). As in the second embodiment, as a result of their shape and of their material which absorbs light rays, the inner edges of the mask 4 block the light rays coming from the emission zone 11 which are reflected on the protective resin 12, in particular as a result of the edge 431 and the chamfer 432.

[0057] Depending on the embodiment, and particularly in the third embodiment, the mask 4 may also serve to protect electronic components 6 that are located near the optical device 10 but do not form part of the optical device 4 from sunlight. In contrast, in the second embodiment, the mask 4 cannot perform this function, and an additional sunlight protection device 7 is required to protect the electronic components 6 that are located near the LED 1.

[0058] In certain embodiments, and in particular in the first embodiment of the light emitting device 10, the mask 4 is connected via a thermal path 8 to a heat sink 5 arranged near the light emitting device 10, thereby facilitating the cooling of the light emission zone 11. To facilitate the thermal evacuation of the heat coming from the emission zone 11, the mask 4 must have a minimum thickness, which may depend on the material from which the mask 4 is made.

[0059] Advantageously, the mask 4 may form a Faraday cage inside which the light source 1 (or LED 1) is placed and which limits the passage of ambient electromagnetic waves in the direction of the light source 1. In one embodiment, the Faraday cage formed by the mask 4 also protects the equipment surrounding the LED 1 from electromagnetic radiation coming from the LED 1.

[0060] Finally, the light-emitting device according to the invention makes it possible to overcome various problems encountered during the use of LED-type light sources in automotive optical systems, more particularly when the protective housing of the LED generates light reflections that tend to disrupt the image projected by the light-emitting device.

[0061] When placed as close as possible to the light source, the mask according to the invention makes it possible to eliminate reflected light rays while preserving a useful light beam substantially equivalent to that obtained without the mask.

[0062] In one embodiment, the mask according to the present invention is in contact with the light emission zone of the LED and can therefore evacuate heat generated by the LED via a thermal path connecting the mask to a heat sink.

[0063] Advantageously, the mask according to the invention also protects the LED and the electronic components surrounding the LED from sunlight that tends to be transmitted through the lens of the light emitting device, as well as from electromagnetic radiation.

Claims

1. A light-emitting device (10) comprising an optical device (3) and a first printed circuit board (2), on which a light source (1) comprising a light-emitting zone (11) and a protective housing (12) surrounding the light-emitting zone (11) is fixed, wherein a first height (h1) of the protective housing (12) relative to a flat surface (21) of the first printed circuit board (2), measured in a first direction (d1) directed toward the optical device (3) perpendicular to the flat surface (21), is greater than a second height (h2) of the light-emitting zone (11) relative to the flat surface (21) in the first direction (d1); The light-emitting device (10) comprises a mask (4) arranged between the optical device (3) and the light-emitting zone (11) so as to prevent light rays coming from the light-emitting zone (11) from being reflected on the protective housing (12) and reaching the optical device (3), the mask (4) is in direct contact with the first printed circuit board (2) and / or the light source (1), A light emitting device (10).

2. 2. The light-emitting device according to claim 1, characterized in that the mask (4) abuts directly against the light-emitting zone (11) and / or against the protective housing (12) of the light source (1).

3. 3. The light-emitting device according to claim 1 or 2, characterized in that the mask (4) has an opening (42) extending along a main surface (41) and defined by an inner edge (43) for passing light rays generated by the light-emitting zone (11), the inner edge (43) protruding from the main surface (41) or being continuous with the main surface (41).

4. 4. The light-emitting device of claim 3, wherein the end (431) of the inner edge (43) of the mask has a chamfer (432) directed towards the light-emitting zone (11), for example a 45-degree chamfer.

5. 5. A light-emitting device (10) according to claim 3, characterized in that the inner edge (43) of the mask (4) protrudes from the main surface (41) of the mask (4), and the end (431) of the inner edge directly abuts the light-emitting zone (11) so as to bound the periphery of the light-emitting zone (11).

6. 6. The light-emitting device (10) of claim 5, wherein the mask (4) is in direct contact with a heat sink (5) arranged near the light-emitting device (10) so as to promote cooling of the light-emitting zone (11).

7. 7. A light-emitting device (10) according to claim 5 or 6, characterized in that the mask (4) is made of a flexible material that allows the inner edge (43) to conform to the shape of the light-emitting zone (11).

8. A light-emitting device according to any one of claims 3 to 7, characterized in that the inner edge (43) of the mask (4) is continuous with the main surface (41) of the mask (4), and a portion (411) of the main surface of the mask is in direct contact with the protective housing (12).

9. Light-emitting device (10) according to any one of claims 1 to 8, characterized in that the mask (4) is made of metal, in particular aluminium or stainless steel.

10. Light-emitting device (10) according to any one of claims 1 to 9, characterized in that the mask (4) forms a Faraday cage inside which the light source (1) is placed.

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