LIGHTING AND/OR SIGNALING DEVICE FOR AN AUTOMOTIVE VEHICLE
20170059110 ยท 2017-03-02
Inventors
- Benoit Reiss (Magency, FR)
- Pierre ALBOU (Paris, FR)
- Etienne Pauty (Bagnolet, FR)
- Vanesa Sanchez (Bois Colombes, FR)
- Antoine DE LAMBERTERIE (Paris, FR)
- Gilles Le-Calvez (Rueil Malmaison, FR)
Cpc classification
B60Q2400/30
PERFORMING OPERATIONS; TRANSPORTING
F21S43/14
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
H10H20/813
ELECTRICITY
F21S43/31
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/148
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21Y2105/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/663
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S41/338
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
B60Q1/28
PERFORMING OPERATIONS; TRANSPORTING
F21S41/60
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
Abstract
A lighting device for an automotive vehicle comprising at least two semiconductor light sources that can be selectively activated and at least one optic for shaping at least a portion of the light rays emitted by either or both of the light sources with the aim of generating at least two lighting and/or signaling functions. The device is configured so that a first function requires the activation of the first semiconductor light source and a second function requires the activation of the second semiconductor light source. At least one of the light sources is a semiconductor light-source comprising a light-emitting rods.
Claims
1. A lighting device for an automotive vehicle, comprising at least a first semiconductor light source and a second semiconductor light source that can be selectively activated and at least one optic for shaping the light emitted by either or both of said first semiconductor light source and said second semiconductor light source with the aim of generating at least two lighting and/or signaling functions, said lightning device being configured so that a first lighting and/or signaling function requires an activation of said first semiconductor light source and a second lighting and/or signaling function requires an activation of said second semiconductor light source, at least said second semiconductor light source comprising a plurality of light-emitting rods of submillimeter size.
2. The lighting device according to claim 1, wherein said second lighting and/or signaling function solely requires said activation of said second semiconductor light source.
3. The lighting device according to claim 2, wherein said lighting and/or signaling function generates the formation of a light beam of fog beam type.
4. The lighting device according to claim 2, wherein said second lighting and/or signaling function generates the formation of a light beam of low beam type.
5. The lighting device according to claim 1, wherein said second lighting and/or signaling function requires the simultaneous activation of said first semiconductor light source and said second semiconductor light source.
6. The lighting device according to claim 5, wherein said second lighting and/or signaling function generates the formation of a light beam of high beam type.
7. The lighting device according to claim 6, wherein said generates the formation of a light beam of low beam type.
8. The lighting device according to claim 1, wherein said plurality of light-emitting rods are on a same substrate.
9. The lighting device according to claim 1, wherein said plurality of light-emitting rods take the general form of a cylinder, in particular with a polygonal cross section.
10. The lighting device according to claim 1, wherein a height of said plurality of light-emitting rods is between 1 and 10 micrometers.
11. The lighting device according to claim 1, wherein said plurality of light-emitting rods are each delimited by a terminal face and a circumferential wall that extends along a longitudinal axis of said plurality of light-emitting rods, defining a height thereof, the light being emitted at least from said circumferential wall.
12. The lighting device according to claim 11, wherein said wherein a largest dimension of said terminal face is smaller than 10 micrometers, preferably smaller than 5 micrometers.
13. The lighting device according to claim 1, wherein said first semiconductor light source and said second semiconductor light source have separate luminances.
14. The lighting device according to claim 1, wherein a distance (d1, d2, d3) that separates two immediately adjacent light-emitting rods is equal to a minimum of 2 micrometers and a maximum of 100 micrometers.
15. The lighting device according to claim 14, wherein said a distance (d3) that separates said two immediately adjacent light-emitting rods of two adjacent light sources is equal to said distance (d1, d2) that separates said two immediately adjacent light-emitting rods of the same light source.
16. The lighting device according to claim 2, wherein said plurality of light-emitting rods are on a same substrate.
17. The lighting device according to claim 2, wherein said plurality of light-emitting rods take the general form of a cylinder, in particular with a polygonal cross section.
18. The lighting device according to claim 2, wherein a height of said plurality of light-emitting rods is between 1 and 10 micrometers.
19. The lighting device according to claim 2, wherein said plurality of light-emitting rods are each delimited by a terminal face and a circumferential wall that extends along a longitudinal axis of said plurality of light-emitting rods, defining a height thereof, the light being emitted at least from said circumferential wall.
20. The lighting device according to claim 2, wherein said first semiconductor light source and said second semiconductor light source have separate luminances.
Description
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0039]
[0040]
[0041]
[0042]
[0043]
[0044]
[0045]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] A lighting device for an automotive vehicle comprises a light-emitting device 1, in particular housed in a housing closed by an outer lens and which defines an inner volume for accommodating the light-emitting device 1. The light-emitting device 1 is combined with an optic for shaping 2 at least a portion of the light rays emitted by the light-emitting device 1 via the output of the housing of the lighting device.
[0047] As explained above, the term lighting device covers an interior lighting device, an exterior lighting device or a signaling device. The example that will be described in more detail relates, in a non-limiting manner, to an exterior lighting function of the vehicle.
[0048] The light-emitting device 1 is, in this instance, arranged so as to form two separate light sources 4, 6, and, in particular, separate in that the luminance of a first light source 4 is higher than the luminance of the other one of the two light sources 6. At least one of these light sources 4, 6 is a semiconductor source, comprising submillimeter-sized light-emitting rods. According to different variant embodiments, it may be envisaged (as illustrated by way of example in
[0049] The structure of a semiconductor light source 4 comprising submillimeter-sized light-emitting rods 8 will now be described, referring in particular to
[0050] The light source 4 comprises a plurality of light-emitting rods 8 which arise on at least one substrate 10. Each light-emitting rod 8, formed, in this instance, using gallium nitride (G.sub.n), protrudes perpendicularly, or substantially perpendicularly, from the substrate 10, based, in this instance, on silicon or silicon carbide. Other materials may be used without departing from the scope of the invention. By way of example, the light-emitting rods 8 could be made from a compound based on aluminum nitride and gallium nitride (Al.sub.nG.sub.n), or from a compound based on aluminum, indium and gallium.
[0051] The substrate 10 has a bottom face 12, to which a first electrode 14 is added, and a top face 16, protruding from which are the light-emitting rods 8 and to which a second electrode 18 is added. Various layers of materials are superposed over the top face 16, in particular after the light-emitting rods 8 have been grown from the substrate 10, achieved, in this instance, using a bottom-up approach. Among these various layers, at least one layer of electrically conductive material may be found, in order to allow the light-emitting rods 8 to be supplied with electrical power. This layer is etched in such a way as to connect a given light-emitting rod 8 to another, the switching on of these light-emitting rods 8 then being able to be controlled simultaneously by a control module (not shown). It is possible to envisage that at least two light-emitting rods 8, or at least two groups of light-emitting rods 8, are arranged so as to be switched on separately, i.e. selectively, via a system for controlling the switching on thereof.
[0052] The light-emitting rods 8 stretch out from the substrate 10 and, as can be seen in
[0053] Each light-emitting rod 8 extends along a longitudinal axis 22 defining the height thereof, the base of each light-emitting rod 7 being positioned in a plane 24 of the top face 16 of the substrate 10.
[0054] The light-emitting rods 8 of one and the same light source 4, 6 advantageously take the same form. They are each delimited by a terminal face 26 and by a circumferential wall 28 that extends along the longitudinal axis 22. When the light-emitting rods 8 are doped and undergo polarization, the resulting light as output from the semiconductor source 4, 6 is essentially emitted from the circumferential wall 28, it being understood that the light rays may also exit from the terminal face 26. As a result, each light-emitting rod 8 acts as a single light-emitting diode and the density of the light-emitting rods 8 present for a light source 4 improves the luminous efficiency of this light source 4.
[0055] The circumferential wall 28 of a light-emitting rod 8, corresponding to the gallium nitride shell, is covered by a transparent conductive oxide (TCO) layer 29 that forms the anode of each light-emitting rod 8 which complements the cathode formed by the substrate 10. This circumferential wall 28 extends along the longitudinal axis 22 from the substrate 10 up to the terminal face 26, the distance from the terminal face 26 to the top face 16 of the substrate 10, from which the light-emitting rods 8 arise, defining the height of each light-emitting rod 8. By way of example, it is envisaged that the height of a light-emitting rod 8 is between 1 and 10 micrometers, while it is envisaged that the greatest transverse dimension of the terminal face 26, perpendicular to the longitudinal axis 22 of the light-emitting rod 8 in question, is smaller than 2 micrometers. It is also possible to envisage defining the area of a light-emitting rod 8, in a sectional plane perpendicular to this longitudinal axis 22, within a range of determined values, and in particular between 1.96 and 4 square micrometers.
[0056] It is understood that during the formation of the light-emitting rods 8, the height may be altered from one light source 4, 6 to the other, so as to increase the luminance of the light source 4, 6 when the height is increased. Thus, the height, or heights, of a group of light-emitting rods 8 may be different from that or those of another group of light-emitting rods 8, these two groups forming the same semiconductor light source 4, 6 comprising submillimeter-sized light-emitting rods 8.
[0057] The form of the light-emitting rods 8 may also vary from one device to the other, in particular in terms of the cross section of the light-emitting rods 8 and the form of the terminal face 26.
[0058] Additionally, the form of the terminal face 26 may be substantially planar and perpendicular to the circumferential wall 28, so that it extends substantially in parallel to the top face 16 of the substrate 10, as illustrated in
[0059] In
[0060] The semiconductor light source 4 may furthermore comprise, as illustrated in
[0061] The light source 4, 6 may furthermore comprise a coating 32 of light-reflective material that is positioned between the light-emitting rods 8 in order to divert the rays which are initially oriented toward the substrate 10 toward the terminal face 26 of the light-emitting rods 8. Stated otherwise, the top face 16 of the substrate 10 may comprise a reflective means that reflects the light rays which are initially oriented toward the top face 16 toward the output face of the light source 4, 6. In this way, rays that otherwise would have been lost are recovered. This coating 32 is positioned between the light-emitting rods 8 on the transparent conductive oxide layer 29.
[0062] A lighting or light-emitting device 1 comprising an emitter device will now be described, which emitter device is formed from two semiconductor light sources 4, 6 comprising light-emitting rods 8 and an optic for shaping 2 the light emitted by either or both light sources 4, 6 with the aim of generating at least two lighting and/or signaling functions.
[0063] The light-emitting device 1 comprises, in this instance, a rectangular form, but it will be understood that it may take other general forms without departing from the scope of the invention, in particular a parallelogrammic form.
[0064] In
[0065] In each of these areas 34, 36, a semiconductor light source 4, 6 with submillimeter-sized light-emitting rods 8 is positioned on each side of the separation 37, these two semiconductor light sources 4, 6 being electrically connected so as to be selectively activatable.
[0066] It is advantageous to envisage that the two semiconductor light sources 4, 6 have separate luminances, in particular in the context of application to a dual-function device, i.e. a device capable of carrying out two separate lighting functions. In the following description, a preferred application in which the device may carry out a first lighting function of low beam type and a second lighting function of high beam type is more particularly considered. Multiple distinctions may be drawn between the two areas 34, 36 of the emissive surface, associated, respectively, with one or the other of the lighting functions, it being understood that in this application, it is desired that the activation of the first semiconductor light source 4 positioned in the first area 34 allows the first lighting function to be carried out, i.e. the emission of a low beam, which therefore requires reduced luminance but high flux, while the activation of the second semiconductor light source 6 allows the second lighting function to be carried out, i.e. the emission of a high beam, which therefore requires high luminance, but with reduced flux. It is possible to envisage, without departing from the scope of the invention, that the second lighting function is carried out only by activating the second semiconductor light source 6, while the first semiconductor light source 4 is switched off, or else that this second lighting function is carried out by simultaneously activating the first and second semiconductor light sources 4, 6, the activation of the second semiconductor light source 6 generating a beam that is complementary to the beam formed by the first semiconductor light source 4 in order to produce the beam of high beam type by combination.
[0067] In
[0068] The density of the submillimeter-sized light-emitting rods 8 in each of the semiconductor sources 4, 6 is advantageously different. It is possible to envisage a different, or substantially different, distribution of light-emitting rods 8 in each of the areas 34, 36, or else an identical, or substantially identical, distribution of light-emitting rods 8 in each of the areas 34, 36, the light-emitting rods 8 in this case possibly being electrically connected in their entirety or not according to one light source 4, 6 or the other. A greater density of light-emitting rods 8 for the second area 36, associated with the second light source 6, is advantageously envisaged, which light source 6 is only switched on when a lighting function of high beam type is required.
[0069] The height of the light-emitting rods 8 from one light source 4, 6 to the other is also advantageously different. The light-emitting surface is thus modified by increasing the height of the circumferential wall 28 and the luminance of the second light source 6 with respect to the first light source 4 is increased by increasing the height of at least one of the submillimeter-sized light-emitting rods 8 in the first area 34 bearing the first light source 4.
[0070] It is understood that it is possible to choose between either of these options in order to envisage a second light source 6 whose luminance is higher than the luminance of the first light source 4, or else that they could both be used, it being understood that other means for varying the luminance could be used.
[0071] In
[0072] The optic for shaping 2 the light rays consists, in the illustrated example, of a reflector 42 that has two separate areas 44 and 46, each being capable of receiving the light arising from the two separate areas 34, 36 of the emissive portion. The first area 44 of the reflector 42 receives the rays emitted by the first area 34 of the emissive portion in order to form, via the output of the lighting device, a first beam and the second area 46 of the reflector 42 receives the rays emitted by the second area 36 of the emissive portion in order to form, via the output of the lighting device, a second beam. It is understood that this distribution is theoretical and it must be envisaged that, in reality, the first area 44 of the reflector 42 also contributes to the reflection of the rays emitted by the second area 36 of the emissive portion and, conversely, that the second area 46 of the reflector 42 also contributes to the reflection of the rays emitted by the first area 34 of the emissive portion. In a variant, it is, for example, one and the same single area that is illuminated by the two areas 34 and 36, but with, for example, the first area 34 being focused and the second area 36 being defocused.
[0073] The two areas 34, 36 of the emissive portion can be activated selectively of one another. It is particularly possible to envisage that the second area 36, when it is activated, emits rays that form, after having been reflected by the projection means, a second beam which is complementary to the first beam projected by the projection means when the second area 36 of the emissive portion is activated. The term complementary beam is understood to mean a beam that forms, with the beam produced by the first semiconductor light source 4, a coherent beam when the two sources 4, 6 are controlled so as to simultaneously carry out the emission of the light beam that is specific thereto. These two complementary beams are superposed in order to form a light beam for an automotive vehicle that conforms to regulations, e.g., a low/high beam formed by a low area and a high area or e.g., a low beam formed by a first low area and a second low area.
[0074] As explained above, the case in which the first area 34 of the emissive portion corresponds to a low area (ZC) while the second area 36 of the emissive portion corresponds to a high area (ZR) will be more particularly described. The two areas 34, 36 of the emissive portion can be activated selectively of one another and it is envisaged to activate only the first area 34, referred to as the low area, in order to form a headlight corresponding to low beam headlight, i.e. a dipped beam headlight that is suitable for not dazzling the occupants of another vehicle (the beam that can be seen in
[0075] As illustrated in
[0076] So that the low beam conforms to regulations, the cutoff must have sufficient contrast.
G(x)=Log10[L(x)]Log10[L(x+step)].
[0077] The aim is that a value of the difference between the maximum contrast (point A) and the level of 1% of the maximum luminance (point B) does not exceed 0.2 mm and, preferably, it must not exceed 0.1 mm.
[0078] Additionally, in order to guarantee a good illumination range in low beam, the maximum intensity in low beam must be placed as close possible below the cutoff, which, on the luminance map of
[0079] As illustrated in
[0080] It is understood that the separation between the first area 34 and the second area 36 of the light-emitting device 1 is non-emissive, the separation possibly being formed by an opaque wall protruding from the substrate 10 between the light-emitting rods 8 that are positioned on the border of each area 34, 36. This separation creates, in the high beam obtained via the combined emission of both areas 34, 36 of the emissive portion, an area that is darkened with respect to the rest. In order for the high beam to be as uniform as possible, it is important that this darkened area be reduced to a minimum, i.e. that the areas 34, 36 be as contiguous as possible. On a luminance map such as illustrated in
[0081] The present invention is most particularly applicable to a front headlamp of an automotive vehicle.
[0082] The preceding description clearly explains how the invention allows the set objectives to be achieved, and in particular proposes a lighting device that allows dual-function lighting, i.e. differing lighting with a single shaping optic, to be produced at low cost and without loss of photometric quality. It is understood that an application to a dual-function device allowing lighting of low beam type and high beam type to be produced has more particularly been described, but that the device could easily be applied in order to carry out different functions, possibly including, in particular, a daytime running light function.
[0083] Of course, various modifications may be added to the structure of the lighting device, described above by way of non-limiting example, by a person skilled in the art, as long as it uses at least one semiconductor light source with light-emitting rods, in particular in order to easily vary the luminance from one source to the other. In any event, the invention is not limited to the embodiment specifically described in this document, and extends in particular to any equivalent means and to any technically workable combination of these means.
[0084] By way of example, certain variants that are not represented are described below, although this list is not exhaustive: [0085] the optic for shaping the light rays does not consist of a reflector as described above, but rather consists of at least one lens or of a combination of reflector(s) and lens(es); [0086] the dimensions of the two areas of the emissive portion are substantially equal, it being understood that like above, the rays emitted separately by the first and second areas are diverted by the shaping optic in order to produce two separate lighting and/or signaling beams.
[0087] While the system, apparatus, process and method herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise system, apparatus, process and method, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.