Lighting device for motor vehicles

Abstract

The invention relates to a light-emitting device comprising an optical device and a first printed circuit board on which a light source is mounted, the light source comprising a light emitting zone and a protective housing surrounding the light emitting zone, characterized in that a first height of the protective housing relative to the plane of the first printed circuit board, measured in a first direction directed towards the optical device perpendicular to said plane, is strictly greater than a second height of the light emitting zone relative to the plane measured in the first direction, and a first surface of the housing directed towards the light emitting zone and included between the first and second heights is defined in such a way that light rays from the light emitting zone are prevented from being reflected by the first surface and reaching the optical device.

Description

[Technical Field]

[0001] The invention relates to a lighting device for an automotive vehicle. Summary of the Invention

[0002] Currently, automotive vehicle optical systems include hyper-pixelated LED light sources that allow for the display of images of various shapes. However, the use of such light sources in vehicle optical systems can result in undesirable effects.

[0003] In particular, the clarity of the image projected by the light source can be impaired by the phenomenon that light rays coming from the light emission zone are reflected by elements located in the optical system and in the vicinity of the light emission zone, in particular by reflective surfaces of the protective housing, which overhang the light emission zone of the light source.

[0004] The object of the invention is to provide a light emitting device that makes it possible to overcome the above limitations, in particular the invention makes it possible to provide a simple and reliable light emitting device that makes it possible to filter light reflections on a protective housing adjacent to the light emitting zone of the light emitting device.

[0005] To this end, the invention relates to a light-emitting device comprising an optical device and a first printed circuit board on which a light source is fixed, the first height of the protective housing relative to the plane of the first printed circuit board, measured in a first direction directed towards the optical device perpendicular to said plane, is strictly greater than a second height of the light-emitting zone relative to the plane measured in the first direction. Furthermore, a first surface directed towards the light-emitting zone and included between the first and second heights is defined in such a way that light rays coming from the light-emitting zone are reflected by said first surface and prevented from reaching the optical device.

[0006] In one embodiment of the lighting device, the housing covers and / or protects electrical connections connecting the first printed circuit board to the light source, and / or the first height is determined by the size of the electrical connections.

[0007] In one embodiment of the light emitting device, the first surface is a plane extending between the light emitting zone and the top surface of the housing, and further, the first surface is perpendicular to both the light emitting zone and the top surface, a first angle formed between the first surface and the top surface is equal to 90 degrees, and the first surface has a rounded profile with a radius strictly less than 50 micrometers.

[0008] In one embodiment of the light emitting device, the first surface is a plane adjacent to the light emitting zone, and a second angle formed between the first surface and the light emitting zone is strictly greater than 160 degrees; or - The second angle is strictly less than 90 degrees.

[0009] In one embodiment of the light emitting device, the first surface is roughened, and the roughness of the first surface is strictly greater than 8 micrometers.

[0010] In one embodiment of the light emitting device, a groove is formed in the top surface of the housing adjacent the first surface, the groove defining a housing tab that supports the first surface.

[0011] In one embodiment of the light emitting device, the housing tab extends above the first surface.

[0012] In one embodiment of the light emitting device, the first surface is convex, and the center of curvature of the first surface and the light source are located on the same side of the first surface.

[0013] The accompanying drawings show, by way of example, embodiments of a light-emitting device according to the invention. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 shows a schematic diagram of an embodiment of a light-emitting device according to the invention. [Figure 2]FIG. 2 shows a schematic cross-sectional view of a printed circuit board on which the light emission zone and the protective housing are fixed. [Figure 3] FIG. 3 shows an embodiment of the light source. [Figure 4] FIG. 4 shows light reflection on a protective housing in an embodiment of the housing without the practice of the invention. [Figure 5] FIG. 5 shows a protective housing according to a first embodiment of the invention. [Figure 6] FIG. 6 shows light reflection in a protective housing according to a first embodiment of the invention. [Figure 7] FIG. 7 shows a protective housing according to a second embodiment of the invention. [Figure 8] FIG. 8 shows light reflection in a protective housing according to a second embodiment of the invention. [Figure 9] FIG. 9 shows a protective housing according to a third embodiment of the invention. [Figure 10] FIG. 10 shows light reflection in a protective housing according to a third embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] A first embodiment of a light emitting device according to the invention is shown in FIG.

[0016] The light emitting device 10 includes: a light source 1 having a light emitting zone 11 and a protective housing 12 enclosing the light emitting 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, and an optical device 3, which may for example be a lens; Mainly provide for.

[0017] Preferably, the light source 1 is an LED, the structure of which is shown in detail in Figures 2 and 3. Please note that in Figures 2 and 3, the housing 12 is shown according to a first embodiment, which will be described later in this document. Furthermore, other embodiments of the housing 12, in particular second and third embodiments, will also be described later in this document.

[0018] FIG. 2 provides a first schematic view of a beam emission zone 11 surrounded by a protective housing 12 .

[0019] The light-emitting zone 11 is divided into a first zone 111, called the active zone, which contains photoluminescent material, and a second zone 112, called the technical zone, which does not contain any photoluminescent material.

[0020] The active zone 111 contains a physical material that emits photons when an electrical current is passed through it, thereby producing blue light. The active zone 111 also contains a phosphor layer that converts the blue light to white light.

[0021] The active zone 111 is also called a "pixel matrix." The photon-emitting material is divided into pixels. Each pixel can be individually controlled to emit photons. Each pixel of the matrix 111 can emit a beam of light over 180 degrees. In one embodiment, the pixel matrix 111 may include 25,000 pixels.

[0022] The active zone 111 defines the emission cone 4 of the light source, which emission cone is shown in more detail in Figure 4. In order to project as sharp an emitting zone as possible, the light rays contained in the emission cone 4 should come directly from the active zone 111, i.e. reflected light rays should not be contained in the emission cone 4.

[0023] The technical zone 112 is located at the periphery of the active zone 111. That is, the technical zone 112 is a thin strip that borders 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 even 300 microns.

[0024] In a preferred embodiment, the protective housing 12 is a protective resin 12 molded around the technical zone 112 .

[0025] In the remainder of this document, "protective housing" and "protective resin" are used interchangeably.

[0026] The light emitting zone 11 and the protective resin 12 are fixed to the flat surface 21 of the first printed circuit board 2 .

[0027] A first direction d1 is defined perpendicular to the plane 21 of the first printed circuit board 2, and the direction d1 is directed toward the optical device 3.

[0028] In this described embodiment, a first height h1 of the protective resin 12 relative to the plane 21, measured in the first direction d1, is strictly greater than a second height h2 of the light emitting zone 11 relative to the plane 21, measured in the first direction d1. That is, the height h1 of the protective resin 12 exceeds the height h2 of the light emitting zone 11. For example, the height h1 is strictly greater than the height h2, and the difference Δh between the two heights can be, for example, 0.2 to 0.3 mm.

[0029] 3 shows a schematic representation of a light source 1, i.e., LED 1, including the light emitting zone 11 and protective resin 12 described above. In this more detailed view, the structure of LED 1 is more clearly visible. In particular, the pixel matrix 111 is shown associated with the switch matrix 13.

[0030] The LED 1 also comprises a second printed circuit board 14 for controlling the switch matrix 13. The assembly formed by the pixel matrix 111 and the switch matrix 13 is fixed to the second printed circuit board 14, for example by soldering.

[0031] The second printed circuit board 14 allows the state of each pixel of the LED 1 to be independently controlled to be lit or extinguished. A network of wired connections 15 allows each pixel to be controlled. The wired connections 15 are arranged between the light emitting surface 11 and the second printed circuit board 14.

[0032] The protective resin 12 serves to protect the network of wired connections 15. To this end, the protective resin 12 completely encapsulates the network of wired connections 15. The height difference Δh between the light-emitting surface 11 and the protective resin 12 is therefore due to the volume occupied by the network of wired connections 15 and the extra thickness of the resin required to encapsulate the ends of the network of wired connections 15 that are connected to the light-emitting surface 11.

[0033] Furthermore, to further improve the thermal insulation of the wired connection network, the protective resin is preferably light in color so as not to absorb heat.

[0034] The excessive thickness of protective resin 12 and its ability to reflect light contribute to the occurrence of parasitic light reflections in LED 1. Specifically, in the example of housing 17 shown in FIG. 4 without implementing the invention, housing 17 may have at least a partially rounded surface 171 adjacent to light-emitting surface 11. Thus, without implementing the invention, the geometry of housing 17 may allow light rays R1 coming from light-emitting zone 11 to be reflected by the housing surface, particularly by the rounded edges of housing 17, to generate light beam R2, with some of the light rays being included in cone 4 and reaching optical device 3.

[0035] In order to limit the amount of reflected light rays reaching the optical device 3, the housing 12 according to the invention has a first surface 121 directed towards the light emitting zone 11 and included between a first height h1 and a second height h2, the first surface being defined so as to prevent light rays coming from the light emitting zone 11 being reflected at said first surface 121 and reaching the optical device 3.

[0036] In one preferred embodiment, all surfaces 121 of the housing that are oriented towards the light emitting zone 11 and that are included between the first height h1 and the second height h2 are defined so as to prevent light rays coming from the light emitting zone 11 from being reflected by these surfaces 121 and reaching the optical device 3.

[0037] In the remainder of this document, the term "surface 121" or "first surface 121" refers to one or more first surfaces 121 that are defined to prevent light rays coming from the light emitting zone 11 from being reflected by these surfaces 121 and reaching the optical device 3.

[0038] 5 to 10, various embodiments of the surface 121 are described below. In the described embodiments, the first surface 121 is a plane adjacent to the light emitting zone 11.

[0039] A first embodiment of the surface 121 is shown in detail in Figure 5. In this embodiment, the first surface 121 extends between the light emitting zone 11 and the top surface 122 of the housing 12. Furthermore, the first surface 121 is perpendicular to both the light emitting zone 11 and the top surface 122. Furthermore, a first angle 123 formed between the first surface 121 and the top surface 122 is equal to 90 degrees. Furthermore, the first angle 123 has a rounded portion 125 with a radius that is strictly less than 50 micrometers.

[0040] 6, in a first embodiment of the invention, ray R3 coming from emission zone 11 can be reflected by first surface 121. In this case, the reflection produces reflected ray R4, which is substantially symmetric to ray R3 along an axis of symmetry perpendicular to surface 121. Ray R4 thus produced passes through cone 4 without reaching optical device 3.

[0041] A second embodiment of the surface 121 is shown in detail in Figure 7. In this embodiment, the second angle 124 formed between the first surface 121 and the light emitting zone 11 is strictly greater than 135 degrees, or strictly greater than 140 degrees, or strictly greater than 150 degrees. Grazing rays coming from the light emitting zone, i.e. rays having a path close to the first surface 121, are therefore reflected in the outer zones of the light emitting device.

[0042] 8, in the second embodiment of the invention, a light ray R5 coming from the emission zone 11 is reflected by the first surface 121. In this case, the reflection produces a reflected light ray R6, which is substantially symmetrical to the light ray R5 along an axis of symmetry perpendicular to the surface 121. The light ray R6 thus produced is directed towards the outside of the light-emitting device 10. Therefore, the light ray R6 does not reach the optical device 3.

[0043] A third embodiment of the surface 121 is shown in detail in FIG. 9 . In this embodiment, the second angle 124 formed between the first surface 121 and the light emission zone 11 is strictly less than 90 degrees. Advantageously, a V-shaped groove 126 is formed in the upper surface 122 of the housing 12 near the surface 121. The groove 126 defines a housing tab 127 that supports the surface 121 and a free space that provides flexibility to the housing tab 127. In particular, since the housing 12 is preferably manufactured by molding, it is advantageously designed so that it can be easily demolded. In the illustrated embodiment, the free space created by the groove 126 and the flexibility of the tab 127 allow the housing 12 to be demolded.

[0044] Preferably, the housing tabs 127 extend above the first surface 121 .

[0045] 10 , in a second embodiment of the invention, a light ray R7 coming from the light ray emission zone 11 can be reflected by the first surface 121. In this case, the reflection produces a reflected light ray R8, which is substantially symmetrical to the light ray R7 along an axis of symmetry perpendicular to the surface 121. The light ray R8 thus produced is confined to a zone close to the emission zone 11. Therefore, the light ray R8 does not reach the optical device 3.

[0046] In a fourth embodiment, the first surface 121 is roughened: that is, the first surface 121 has protrusions and depressions in the form of small particles densely packed together. In this embodiment of the invention, the physical properties of the first surface 121 are thus modified to reduce light reflection at the first surface 121. Specifically, the presence of a granular structure on the first surface 121 diffuses light. The roughness Ra of the roughening of the first surface 121 can be quantified by measuring the average peaks and valleys of the first surface 121 over a length of the first surface 121. Advantageously, the roughness Ra of the roughening of the first surface 121 is strictly greater than 8 micrometers.

[0047] In the fourth embodiment, even if the shape of the housing 12 tends to cause reflection of light rays coming from the emission zone 11, the roughening of the first surface 121 weakens the reflection of light.

[0048] Alternatively, the fourth embodiment can be combined with any one of the first, second, or third embodiments, which allows enjoying the combined effect of the shape and roughening of the first surface 121.

[0049] In an alternative or additional embodiment to the above embodiment, the first surface 121 may be convex, and the center of curvature of the first surface 121 and the light source 1 may be located on the same side of the first surface 121 .

[0050] In other words, when two spaces separated from each other by the first surface 121 are considered, only one of the two spaces includes both the center of curvature of the first surface 121 and the light source 1 .

Claims

1. A light-emitting device (10) comprising an optical device (3) and a first printed circuit board (2) to which a light source (1) is fixed, the light source (1) including a light emitting zone (11) and a protective housing (12) surrounding the light emitting zone (11), wherein a first height (h1) of the protective housing (12) measured in a first direction (d1) directed towards the optical device (3), the first height (h1) of the protective housing (12) relative to a plane (21) of the first printed circuit board (2). is strictly greater than a second height (h2) of the light emitting zone (11) relative to the plane (21) measured in the first direction (d1), and a first surface (121) of the housing (12) directed towards the light emitting zone (11) and included between the first height (h1) and the second height (h2) is determined so as to prevent light rays coming from the light emitting zone (11) from being reflected by the first surface (121) and reaching the optical device (3).

2. 2. The light-emitting device of claim 1, wherein the housing (12) covers and / or protects electrical connections connecting the first printed circuit board (2) to the light source (1), and / or the first height (h1) is determined by the size of the electrical connections.

3. The first surface (121) is a plane extending between the light emitting zone (11) and the upper surface (122) of the housing (12); the first surface (121) is perpendicular to both the light emitting zone (11) and the top surface (122); 3. The light-emitting device according to claim 1, wherein the first angle (123) formed between the first surface (121) and the top surface (122) is equal to 90 degrees and the light-emitting device has a rounded profile (125) with a radius strictly less than 50 micrometers.

4. The first surface (121) is a plane adjacent to the light emitting zone (11), the second angle (124) formed between said first surface (121) and said light emission zone (11) is strictly greater than 160 degrees, or - said second angle (124) is strictly less than 90 degrees; 3. The light emitting device according to claim 1 or 2.

5. The light-emitting device (10) according to any one of claims 1 to 4, characterized in that the first surface (121) is roughened, and the roughness of the roughening of the first surface (121) is strictly greater than 8 micrometers.

6. A light-emitting device (10) according to any one of claims 1 to 5, characterized in that a groove (126) is formed in the upper surface (122) of the housing (12) near the first surface (121), the groove (126) defining a housing tab (127) that supports the first surface (121).

7. 7. The light emitting device (10) of claim 6, wherein the housing tab (127) extends above the first surface (121).

8. The light-emitting device (10) according to any one of claims 1 to 7, characterized in that the first surface (121) is convex, and the center of curvature of the first surface (121) and the light source (1) are located on the same side of the first surface (121).

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