LIGHT SOURCE FOR THE SIGNALLING SYSTEM OF A MOTOR VEHICLE

Abstract

A light source a matrix arrangement of light sources of a motor vehicle lighting module includes a substrate having an upper face, a lower face opposite the upper face, and an electronic circuit. At least one light-emitting element is mounted on the upper face of the substrate and includes a light-emitting part. Also included is an optical device for forming the light beams emitted by the light-emitting element and the lower face includes connection contacts connected to the electronic circuit, the electronic circuit being adapted to power the at least one light-emitting element. The light-emitting part of at least one light-emitting element has a surface area of less than 40,000 m.sup.2, and the beam-forming optical device has an optical element on the upper face of the substrate and/or on the light-emitting part of the at least one light emitting element.

Claims

1. A light source for an array arrangement of light sources for a motor vehicle signaling lighting module, the light source having: a substrate having an upper face, a lower face opposite to the upper face, and an electronic circuit, at least one electroluminescent element which is mounted on the upper face of the substrate and has a light-emitting part, an optical unit for shaping the rays emitted by the at least one electroluminescent element, said lower face having connection contacts connected to the electronic circuit, the electronic circuit being designed to supply power to the at least one electroluminescent element, the light-emitting part of said at least one electroluminescent element having a surface area less than 40 000 m.sup.2, said optical unit being comprising an optical element mounted on the upper face of the substrate and/or on the light-emitting part of the at least one electroluminescent element, wherein an optical element of the optical unit for shaping the light rays is a reflector of the total internal reflection type.

2. The light source as claimed in claim 1, wherein the surface area of the emitting part of the at least one electroluminescent element is at least two times smaller than the surface area of the upper face of the substrate and/or the surface area of the emitting part of the at least one electroluminescent element is at least two times smaller than the surface area of the useful output surface of the optical unit for shaping the light rays coming from the electroluminescent element.

3. The light source as claimed in claim 1, wherein the optical element has a portion having an output surface of which a cross section in a plane parallel to the upper face of the substrate is oval or elliptical.

4. The light source as claimed in claim 1, wherein the optical unit for shaping the rays emitted by the electroluminescent element concentrates said rays more vertically than horizontally when the light source is mounted in a signaling lighting module mounted on a motor vehicle.

5. The light source as claimed in claim 1, wherein the optical unit for shaping the light rays emitted by the electroluminescent element is asymmetrical when the light source is mounted in a signaling lighting module mounted on a motor vehicle.

6. The light source as claimed in claim 1, wherein the optical unit for shaping the light rays has a transparent optical element disposed such there is an empty space between the transparent optical element and the electroluminescent element.

7. The light source according to claim 1, wherein the mounted optical element is a transparent optical element and is disposed such that there is substantially no empty space between the transparent optical element and the electroluminescent element, the optical unit for shaping the light rays comprising a material with an optical index greater than 1.2 in direct contact with the electroluminescent element.

8. The light source as claimed in claim 1, wherein the reflector is mounted on the upper face and in that a profile of the reflector in a plane perpendicular to the upper face of the substrate is parabolic.

9. The light source as claimed in claim 10, wherein the total internal reflection reflector has a planar output surface.

10. The light source as claimed in claim 10, wherein the total internal reflection reflector has an output surface having optical patterns able to redirect or disperse the light rays coming from the electroluminescent element.

11. The light source as claimed in claim 1, wherein an antireflection coating and/or a mineral coating is applied to the shaping optical unit and/or to the sides of the light source.

12. The light source as claimed in claim 1, wherein the light source has a footprint and/or connection contacts which is/are asymmetrical along at least a plane normal to a plane of the substrate that passes through its center.

13. The light source as claimed in claim 1, wherein the electronic circuit of the substrate has an integrated circuit designed to supply power to the at least one electroluminescent element.

14. The light source as claimed in claim 1, wherein it has a plurality of electroluminescent elements each corresponding to an optical element of the optical unit for shaping the light rays.

15. A signaling device contributing to and/or performing a regulatory rear position light function and/or brake light function and/or turn indicator function, wherein it has a support for an array arrangement of light sources as claimed in claim 1, forming a lighting module.

16. A method for manufacturing a light source as claimed in claim 1, wherein the method comprises: a step of making up a common substrate from electroluminescent elements comprising a plurality of electroluminescent elements, having an upper face on which are mounted the electroluminescent elements and a lower face having connection contacts and electronic circuits for connecting the electroluminescent elements, such that the electroluminescent elements can be supplied with power via the lower face of the common substrate, a step of mounting optical units for shaping the light rays coming from the electroluminescent elements by positioning and assembling a matrix arrangement of optical elements so as to assemble said optical elements in line with electroluminescent elements mounted on the common substrate, a step of singulating the common substrate, yielding a plurality of light sources.

17. The light source as claimed in claim 2, wherein the optical element has a portion having an output surface of which a cross section in a plane parallel to the upper face of the substrate is oval or elliptical.

18. The light source as claimed in claim 2, wherein the optical unit for shaping the rays emitted by the electroluminescent element concentrates said rays more vertically than horizontally when the light source is mounted in a signaling lighting module mounted on a motor vehicle.

19. The light source as claimed in claim 2, wherein the optical unit for shaping the light rays emitted by the electroluminescent element is asymmetrical when the light source is mounted in a signaling lighting module mounted on a motor vehicle.

20. The light source as claimed in claim 2, wherein the optical unit for shaping the light rays has a transparent optical element disposed such there is an empty space between the transparent optical element and the electroluminescent element.

Description

[0131] The present invention will now be described by way of examples that are merely illustrative and that in no way limit the scope of the invention, and with reference to the accompanying illustrations, in which:

[0132] FIG. 1 schematically and partially depicts a sectional view through a light source according to a first embodiment of the invention;

[0133] FIG. 1p schematically and partially depicts a perspective view of a light source according to a first embodiment of the invention;

[0134] FIG. 2 schematically and partially depicts a sectional view through a light source according to a variant of the first embodiment of the invention;

[0135] FIG. 3p schematically and partially depicts a sectional view through a light source according to a second embodiment of the invention;

[0136] FIG. 3c schematically and partially depicts a sectional view through a light source according to a second embodiment of the invention;

[0137] FIG. 4t schematically and partially depicts a side view of a light source according to a third embodiment of the invention;

[0138] FIG. 4l schematically and partially depicts a side view of a light source according to a third embodiment of the invention;

[0139] FIG. 4c schematically and partially depicts a side view of a light source according to a variant of a third embodiment of the invention;

[0140] FIG. 4p schematically and partially depicts a perspective view of a light source according to a variant of a fourth embodiment of the invention:

[0141] FIG. 5V schematically and partially depicts a sectional view through a support for an array arrangement of light sources according to a fifth embodiment of the invention,

[0142] FIG. 5H schematically and partially depicts a sectional view through a support for an array arrangement of light sources according to a fifth embodiment of the invention.

[0143] In the following description, elements which are identical in terms of structure or function and appear in different figures retain the same references unless indicated otherwise.

[0144] [FIG. 1] depicts a sectional view through a light source 100 according to a first embodiment of the invention, along a plane orthogonal to the substrate 120.

[0145] The light source 100 of [FIG. 1] forms part of an array arrangement of identical light sources of a motor vehicle lighting module.

[0146] The light source 100 has a substrate 120 provided with an upper face 122, a lower face 121 opposite to the upper face 122, and an electronic circuit 150.

[0147] The substrate 120 defines the footprint of the light source 100. In this case, the substrate 120 and therefore the light source 100 have a square footprint with a side length of 200 m.

[0148] The light source 100 has an electroluminescent element 130 of the micro-LED type which is mounted on the upper face 122 of the substrate 120 and has a light-emitting part, said emitting part having a surface area of 900 m.sup.2 as viewed from an axis normal to the upper face 122 of the substrate 120.

[0149] The light source 100 in addition has an optical unit 140 for shaping the light rays. In the embodiment of [FIG. 1], the optical unit 140 for shaping the light rays forms, above the upper face 122 of the substrate 120, an ellipsoidal diopter designed to concentrate the light rays coming from the at least one electroluminescent element 130 around an axis normal to the substrate 120. The emitting surface of the electroluminescent element 130 is close to said axis normal to the substrate 120. Spacers secured to the substrate 120 keep the optical unit 140 for shaping the light rays at a predefined distance from the substrate 120 such that an empty space separates the electroluminescent element 130 from the optical unit 140 for shaping the light rays. The optical unit 140 for shaping the light rays is adhesively bonded to the spacers 141 so as to ensure it is fixed.

[0150] In addition, the lower face 121 has connection contacts 151 connected to the electronic circuit 150, said contacts being in this case made in the form of pads, that is to say contact pads, the electronic circuit 150 being designed to supply power to at least one electroluminescent element 130.

[0151] When the light source 100 is assembled on a support forming a lighting module of a motor vehicle signaling device, it is assembled such that an axis of maximum light intensity is disposed substantially along a front-rear axis of the motor vehicle. The light source 100 is additionally oriented such that the long side of the substrate 120 is substantially horizontal. As a result, the light rays coming from the electroluminescent element 130 are concentrated more about a horizontal plane than about a vertical plane. Such a distribution of the light rays is particularly favorable for realizing a signaling function such as a rear position light function, a brake light function, or a turn indicator function, in accordance with the abovementioned UNECE regulations.

[0152] [FIG. 1p] depicts a perspective view of the light source 100 of [FIG. 1].

[0153] [FIG. 2] depicts a sectional view along a plane orthogonal to the substrate 220 of a light source 200 according to one variant of the first embodiment of the invention.

[0154] The substrate 220 on which the electroluminescent element 230 is mounted and the electroluminescent element 230 are identical to those of [FIG. 1].

[0155] The light source 200 in addition has an optical unit 240 for shaping the light rays. In the embodiment of [FIG. 2], the optical unit 240 for shaping the light rays has reflectors secured to the substrate 220. Said reflectors have a reflective face metallized with copper, with a straight cross section. Said reflectors make it possible to avoid the rays that form an angle with the substrate 220 of less than 20 being deflected toward the inside of the lighting device by the transparent part of the optical unit 240 for shaping the light rays. In the particular case of [FIG. 2], said reflectors are made by an additive process.

[0156] The optical unit 240 for shaping the light rays in addition forms, above the upper face 222 of the substrate 220, a mounted optical element having a planar input face parallel to an upper face 222 of the substrate 220 and an output face having a portion forming an ellipsoidal diopter 242 designed to concentrate the light rays coming from the at least one electroluminescent element 230 about a direction of maximum intensity normal to the substrate 220. The emitting surface of the electroluminescent element 230 is passed through by said normal direction of maximum intensity. The output face also has a planar diopter 241 which is parallel to the upper face 222 of the substrate 220 and is located on a region in line with the reflectors 245, such that the light that comes from the electroluminescent element 230 and is reflected on the reflectors is deflected very little or not at all by the ellipsoidal diopter of the optical unit 240 for shaping the light rays.

[0157] The reflectors 245 also act as spacers and contribute to keeping the transparent part of the optical unit 240 for shaping the light rays at a predefined distance from the substrate 220 such that an empty space separates the electroluminescent element 230 from the optical unit 240 for shaping the light rays. The transparent part of the optical unit 240 for shaping the light rays is adhesively bonded to the reflectors.

[0158] [FIG. 3p] depicts a sectional view through a light source 301 according to a second embodiment of the invention.

[0159] The light source 301 of [FIG. 3p] forms part of an array arrangement of identical light sources of a motor vehicle lighting module.

[0160] The light source 301 has a substrate 320 provided with an upper face 322, a lower face opposite to the upper face 322, and an electronic circuit.

[0161] The light source 301 has an electroluminescent element 330 of the micro-LED type which is mounted on the upper face 322 of the substrate 320 and has a light-emitting part, said emitting part having a surface area of 2000 m.sup.2 as viewed from an axis normal to the outer face of the substrate 320.

[0162] The light source 301 in addition has an optical unit 240 for shaping the light rays. In the embodiment of [FIG. 3p], there is no transparent part in line with the electroluminescent element 330, and the optical unit 340 for shaping the light rays is a reflector of parabolic shape which is designed to reflect the light rays coming from the at least one electroluminescent element 330 so as to concentrate them about an axis normal to the substrate 320. Said axis about which the light rays are concentrated is then an axis of maximum intensity. The emitting surface of the at least one electroluminescent element 330 is close to said axis. The reflector is directly adhesively bonded on the upper face 322 of the substrate 320, leaving the emitting surface of the electroluminescent element 330 free.

[0163] When the light source 301 is arranged on a support forming a lighting module of a motor vehicle signaling device, it is arranged such that the axis of maximum intensity is disposed substantially along a front-rear axis of the motor vehicle.

[0164] [FIG. 3c] depicts a sectional view through a light source 300 according to one variant of the second embodiment of the invention.

[0165] The light source 300 of the variant of [FIG. 3c] differs from that presented in [FIG. 3p] in that it has a conical reflector which is symmetrical about an axis of revolution. Such a reflector can be produced particularly cost-effectively.

[0166] [FIG. 4t] depicts a sectional view through a light source 400 according to a third embodiment of the invention.

[0167] The light source 400 of [FIG. 4t] forms part of a matrix arrangement of light sources identical to a motor vehicle lighting module.

[0168] The substrate 420 on which the electroluminescent element 430 is mounted and the electroluminescent element 430 are identical to those of [FIG. 1].

[0169] The light source 400 in addition has an optical unit 440 for shaping the light rays. In the embodiment of [FIG. 4t], the optical unit 440 for shaping the light rays is an optical unit of the total internal reflection type, also known to those skilled in the art by the acronym TIR. The optical unit 440 for shaping the light rays comprises a transparent portion which is in line with the electroluminescent element 430 and has at least one face on which the rays coming from the electroluminescent element 430 are completely reflected. The optical unit 441 for shaping the light rays is adhesively bonded directly on the electroluminescent element 430 using a transparent adhesive with an optical index similar to that of the optical element, such that rays coming from the electroluminescent element 430 that form a small angle with the plane of the upper face 422 of the substrate 420 are not reflected by an input face. In this way, the loss of light rays is avoided and the effectiveness of the optical unit 441 for shaping the light rays is consequently increased.

[0170] A lateral face of the optical unit 441 for shaping the light rays has a parabolic portion designed to concentrate the light rays coming from the at least one electroluminescent element 430 about a direction of maximum intensity of the light emitted by the light source 400 normal to the substrate 420. A focus of the emitting surface of the at least one electroluminescent element 430 is close to said direction of maximum intensity.

[0171] The optical unit 441 for shaping the light rays has a planar output surface normal to the preferred emission direction, such that the rays deflected by the parabolic portion of the optical unit 441 for shaping the light rays have a small angle of incidence on said output surface, so as to deprioritize the reflection of a ray coming from the electroluminescent element 430 toward the substrate 420, including when said ray has been deflected by total internal reflection by a lateral face of the mounted optical element.

[0172] [FIG. 4l] depicts a perspective view of a light source 401 according to one variant of the third embodiment of the invention.

[0173] In this variant, all the aspects are similar to those of the embodiment of [FIG. 4t]. The variant presented in [FIG. 4l] differs from the embodiment of [FIG. 4t] in that the mounted optical element has tabs which interact with the substrate 420 to ensure a relative positioning of the mounted optical element and the electroluminescent element 430. In this way, the positioning of the mounted optical element is facilitated.

[0174] [FIG. 4c] depicts a perspective view of a light source 403 according to one variant of the third embodiment of the invention.

[0175] In this variant, all the aspects are similar to those of the embodiment of [FIG. 4l] except for the output surface, which is not planar but has a series of optical units in the form of juxtaposed portions 443 having a cylinder of revolution, the axes of said cylindrical portions 443 being oriented along a substantially vertical axis, such that the rays reaching the output surface are dispersed in a horizontal plane. This makes it possible to ensure that the light coming from the signaling module is visible for any observer in visual contact with the lighting module.

[0176] [FIG. 4p] depicts a perspective view of a light source 402 according to the third embodiment of the invention.

[0177] In this variant, all the aspects are similar to those of the embodiment of [FIG. 4l] except for the output surface, which is not planar but has a series of optical units in the form of portions of juxtaposed prisms 442, with faces of said prisms 442 being oriented along an axis perpendicular to a preferred direction for the intensity of the light coming from the light source 402, such that the rays reaching the output surface are redirected in this direction. This makes it possible to ensure that the light coming from the signaling module is emitted in a preferred direction corresponding to a front-rear axis of the vehicle, if the normal to a plane of the support of the light source 402 does not point in the front-rear direction.

[0178] When the light source 402 shown in [FIG. 4p] is assembled on a support forming a lighting module of a motor vehicle signaling device, it is assembled such that the axis of maximum intensity of the light source 402 is disposed substantially along a front-rear axis of the motor vehicle. The light source 402 is in addition oriented such that the long side of the substrate 420 is substantially horizontal. As a result, the light rays coming from the at least one electroluminescent element 430 are concentrated more around a horizontal plane than around a vertical plane. Such a distribution of the light rays is particularly favorable to the performance of a signaling function, such as a rear position light function, brake light function or turn indicator function, according to the aforementioned UNECE regulations.

[0179] [FIG. 5V] depicts a partial view of an array arrangement of light sources from a sectional viewpoint in a plane XXZZ through a support for light sources of a lighting module.

[0180] The light sources 501, 502, 503, 50 . . . etc. each have a substrate provided with an upper face, a lower face opposite to the upper face, an electronic circuit and electrical contacts located on the lower face of the substrate. The substrate has a rectangular footprint, with a large side and a small side.

[0181] The light sources have an electroluminescent element and an optical unit for shaping the light rays. In the embodiment of [FIG. 5V], the optical unit for shaping the light rays from each of the light sources 501, 502, 503, 50 . . . etc. is asymmetrical, such that it is able to concentrate the light rays about a direction of maximum intensity parallel to a front-rear axis XX of the motor vehicle, although the support 511 for the array arrangement of light sources is inclined in a plane XXZZ comprising the front-rear axis XX and a vertical axis ZZ.

[0182] [FIG. 5H] depicts a view of an array arrangement of light sources from a sectional viewpoint in a plane XXYY of a support for light sources of a lighting module, which are similar in all respects to those of [FIG. 5V] except in that the optical unit for shaping the light rays is asymmetrical, such that it is able to concentrate the light rays about a direction of maximum intensity that is parallel to a front-rear axis XX of the motor vehicle, although the support 512 for the array arrangement of light sources is inclined in a plane XXZZ comprising the front-rear axis XX and a vertical axis ZZ.

[0183] The invention is not limited to the embodiments specifically given in this document by way of non-limiting examples, and extends in particular to all equivalent means and to any technically operational combination of these means. As a result, the features, variants and various embodiments of the invention may be combined with one another, in various combinations, as long as they are not mutually incompatible or mutually exclusive.

[0184] For example, it is not difficult to imagine an optical unit for shaping the light rays of which the outer surface forms a diopter, comprising reflectors.