Patent Application
20220412529
The invention relates to the field of luminous lighting and signaling, and more particularly to the field of motor vehicles.
It is generally known how to produce a cutoff-containing lighting beam using one or more deflector-comprising luminous modules. Such a luminous module conventionally comprises a first collector with a first reflective surface of revolution with an elliptical profile, of skullcap shape in a half-space bounded by a horizontal plane. An essentially point-like light source, such as a light-emitting diode, is located at a first focal point of the reflective surface and shines light into the half-space in the direction of said surface. The rays are thus reflected in a convergent manner toward a second focal point of the first reflective surface. A generally planar, auxiliary reflective surface with a cutoff-forming edge level with the second focal point ensures an upward reflection of any rays that do not pass precisely through the second focal point, these rays then being refracted by a thick lens toward the bottom of the lighting beam. This auxiliary reflective surface is commonly referred to as a “deflector” as it “deflects” toward the top of the projecting lens any rays that would otherwise form an upper portion of the lighting beam. This first light beam contains a horizontal cutoff that may be kinked, and corresponds to the type of lighting beam referred to as a low beam. It is also known to provide a second light source and a second collector that forms a second reflective surface, these elements being opposite the first light source, the first collector and the first reflective surface and configured to form a second light beam of the type referred to as a high beam. The second light source may comprise a plurality of separately activatable illuminating regions, and the second reflective surface may be segmented into a plurality of sectors, so as to form a segmented light beam.
Such a luminous module has the drawback of requiring the deflector and the cutoff-forming edge to be positioned with a high degree of precision. Thus, the projecting lens must be a thick lens because of its small focal length, this increasing its weight and complicating the production thereof, in particular as regards sink marks. In addition, the collector has a certain height and, thus, a certain heightwise bulk.
The objective of the invention is to mitigate at least one of the drawbacks of the aforementioned prior art. More particularly, the objective of the invention is to provide a luminous module able to form a light beam, potentially a cutoff-containing light beam, that is compact and more economical to produce.
The subject of the invention is a luminous module, in particular for a motor vehicle, said module comprising a first light source able to emit light rays, and a first reflective surface configured to collect and reflect the light rays emitted by said first light source into a first light beam along an optical axis of the module; a second light source and a second reflective surface configured to collect and reflect the light rays emitted by said second light source into a second light beam along the optical axis; an optical system configured to project the first and second light beams; noteworthy in that the first and second light sources emit the light rays in the same direction, the first and second reflective surfaces are offset along the optical axis, and the optical system is configured to form an image of the second reflective surface.
By forming an image of the second reflective surface, what is meant is that the optical system has a focal point located on or in proximity to the second reflective surface and has a sufficient depth of field. The latter is advantageously at least 30% and more advantageously the entirety of the length, along the optical axis, of the second reflective surface. A projecting lens of large focal length and of small height allows a large depth of field to be obtained. Advantageously, the rays incident on the optical system are parallel to the optical axis or are inclined by less than 25°, and preferably by less than 15°, with respect to said optical axis, so that the paraxial approximation applies.
The first light beam advantageously forms a low automotive lighting beam or one portion of such a beam. It may for example be a beam containing a horizontal flat cutoff or a kinked cutoff. Alternatively, the first light beam allows
The second light beam advantageously forms, in combination with the first light beam, a high automotive lighting beam, and for example a segmented high automotive lighting beam. The second light beam may also be a complementary beam participating in the formation of a low beam or even of an advantageously segmented high beam.
The optical system may comprise a projecting lens or one or more mirrors.
According to one advantageous embodiment of the invention, the first and second reflective surfaces are formed on the same collector.
According to one advantageous embodiment of the invention, the second reflective surface is segmented transversely to the optical axis so as to form adjacent strips of reflective surface, the second light source comprising a plurality of individually activatable light-emitting regions that extend transversely and that are associated with said adjacent strips of reflective surface.
According to one advantageous embodiment of the invention, the second reflective surface comprises a rear edge forming a horizontal cutoff in the second beam.
According to one advantageous embodiment of the invention, the optical system has a focal point located on the second reflective surface or at a distance from said second reflective surface smaller than 10 mm.
According to one advantageous embodiment of the invention, the focal point of the optical system is located on the rear edge of the second reflective surface or at a distance from said rear edge smaller than 10 mm.
According to one advantageous embodiment of the invention, each of the first and second reflective surfaces has an elliptical or parabolic profile.
According to one advantageous embodiment of the invention, the luminous module further comprises an optical concentrating device placed optically between the second light source and the second reflective surface, and configured to concentrate the light rays emitted by said second light source toward a rear edge of the second reflective surface. The optical concentrating device is advantageously a lens or a series of lenses when the second light source comprises a series of individually activatable light-emitting regions.
According to one advantageous embodiment of the invention, the first reflective surface has an elliptical profile with a first focal point corresponding to the first light source and a second focal point, said luminous module further comprising an auxiliary reflective surface with a front edge located at said second focal point, said front edge forming an edge forming a horizontal cutoff, with or without a kink, in the first beam. The auxiliary reflective surface is advantageously planar. It is a question of a deflector. It is advantageously parallel to, or aligned with, the optical axis.
According to one advantageous embodiment of the invention, the rear edge of the second reflective surface is adjacent to, or coincides with, the front edge of the auxiliary reflective surface, which forms a horizontal cutoff, with or without a kink, in the first beam.
According to one advantageous embodiment of the invention, said luminous module further comprises a third light source able to emit light rays, and a third reflective surface adjacent to, and in front of, the second reflective surface, said third surface being configured to collect and reflect the light rays emitted by said third light source into a third light beam along the optical axis.
The third light beam advantageously complements the second light beam so as to form, in combination with the first light beam, a high automotive lighting beam, and for example a segmented high automotive lighting beam.
According to one advantageous embodiment of the invention, the third reflective surface comprises a rear edge forming a horizontal cutoff in the third beam.
According to one advantageous embodiment of the invention, the third reflective surface is segmented transversely to the optical axis so as to form adjacent strips of reflective surface, the third light source comprising a plurality of individually activatable light-emitting regions that extend transversely and that are associated with said adjacent strips of reflective surface.
According to one advantageous embodiment of the invention, the first reflective surface is adjacent to, and behind, the second reflective surface, and the optical system is configured to also form an image of the first reflective surface.
Advantageously, the first and second light beams complement each other to form, in combination with a cutoff-containing light beam formed by another module, a high automotive lighting beam, and for example a segmented high automotive lighting beam.
According to one advantageous embodiment of the invention, the first reflective surface is segmented transversely to the optical axis so as to form adjacent strips of reflective surface, the first light source comprising a plurality of individually activatable light-emitting regions that extend transversely and that are associated with said adjacent strips of reflective surface.
The measures of the invention are advantageous in that they allow a plurality of horizontal-cutoff-containing beams to be produced with a single module, the module remaining compact, in particular heightwise, and simple to produce. Imaging an illuminated reflective surface, with sufficient depth of field, allows a sharp projected luminous image to be obtained and, thus, cutoffs that are also sharp to be produced by means of the edges of the surface in question. In addition, as the paraxial approximation applies, i.e. as the rays that are inclined little with respect to the optical axis and are not very far from said axis, the lens forming the projecting system may be a thin lens, for example of a thickness smaller than 6 mm, this allowing it to be produced in a single plastic injection-molding operation.
In the following description, the notions “front”, “in front of”, “rear” and “behind” are to be understood with respect to a main direction of propagation of the light, namely along the optical axis, from the one or more light sources to an optical projecting system.
The luminous module 2 comprises a second light source 18 and a second reflective surface 20 configured to collect the light rays emitted by the second light source 18 and to reflect them to form a second light beam. As may be seen in
The second reflective surface 20 advantageously has a profile of elliptical or parabolic type. It is advantageously a surface of revolution around an axis parallel to, or coinciding with, the optical axis. Alternatively, it may be a question of a free-form surface or a swept surface or an asymmetric surface. It may also include a plurality of sectors or segments.
The expression “parabolic type” generally applies to reflectors the surface of which has a single focal point, i.e. one region of convergence of the light rays, i.e. one region such that the light rays emitted by a light source placed in this region of convergence are projected to a great distance after reflection from the surface. Projected to a great distance means that these light rays do not converge toward a region located at at least 10 times the dimensions of the reflector. In other words, the reflected rays do not converge toward a region of convergence or, if do they converge, this region of convergence is located at a distance larger than or equal to 10 times the dimensions of the reflector. A parabolic surface may therefore feature or not feature parabolic segments. A reflector having such a surface is generally used alone to create a light beam. Alternatively, it may be used as projecting surface associated with an elliptical-type reflector. In this case, the light source of the parabolic-type reflector is the region of convergence of the rays reflected by the elliptical-type reflector.
The light source 18 is placed at a focal point of the second reflective surface 20 so that its rays are collected and reflected along the optical axis 12.
The projecting lens 14 has a focal point 14.1 that is advantageously located along the optical axis 12, plumb with the second light source 18 or, as in the present case, behind said source. In the present case, the focal point 14.1 is located on the second reflective surface 20 or in proximity thereto, and preferably less than 10 mm therefrom, and more preferably less than 5 mm therefrom. Furthermore, the projecting lens 14 has a depth of field sufficient to obtain stigmatism for at least some of the second reflective surface 20. Advantageously the depth of field of the projecting lens 14 is at least 30% and advantageously the entirety of the extent, along the optical axis, of the second reflective surface 20
The projecting lens 14 is advantageously a so-called thin lens, and for example smaller than 6 mm in thickness. This is possible when the rays to be deviated have a small inclination. To this end, at least some of these reflected rays may have angles of inclination a in a vertical plane with respect to said axis that are smaller than or equal to 25°, and preferably smaller than or equal to 10°, so that the so-called paraxial approximation applies. Advantageously, these rays are reflected by the rear portion of the second reflective surface 20.
By virtue of the arrangement such as described above, the projecting lens 14 thus images the second reflective surface 20 when the latter is illuminated, and more particularly images the segment of reflective surface closest the focal point 14.1. Advantageously, the latter is located on the rear edge 20.1 of the second reflective surface 20, so as to ensure the edge in question is imaged. This allows a vertically concentrated second light beam to be produced. In practice however, the focal point 14.1 is located at a distance from the rear edge 20.1, namely in front of said edge, in order to vertically widen the second light beam. Imaging with a certain precision the rear edge 20.1 of the second reflective surface 20 allows a lower horizontal cutoff to be formed in the second light beam 22. The second reflective surface 20 has a front edge 20.2 that will define the upper limit of the second light beam 22.
The second reflective surface 20, if it is of elliptical type, has a second focal point located in front of the projecting lens 14 and at distance from the optical axis 12. It will be noted that it is also possible for this focal point to be located behind the projecting lens and/or on the optical axis, provided that it is in proximity to the lens, so as to decrease the width of the beam at the entrance face of the projecting lens.
The first and second reflective surfaces 6 and 20 and the auxiliary reflective surface 8 (the deflector) may be formed on the same carrier forming a collector 24. The shell- or skullcap-shaped collector 24 is advantageously made of materials that resist heat well, and for example of glass or of synthetic polymers such as polycarbonate PC or polyetherimide PEI.
The second embodiment differs from the first embodiment essentially in the presence of a third light source and of a third reflective surface forming a third light beam.
The luminous module 102 comprises a third light source 128 arranged in front of the second light source 118. It illuminates in the same direction as the first and second light sources, in the present case vertically downward considering the orientation of
The third light source 128 is placed at a focal point of the third reflective surface 130 so that its rays are collected and reflected along the optical axis 112. At least some of these reflected rays may have angles of inclination β in a vertical plane with respect to said axis that are smaller than or equal to 25°, and preferably smaller than or equal to 10°, so that the so-called paraxial approximation applies. Advantageously, these rays are reflected by the rear portion of the third reflective surface 130. The third light source 128, the third reflective surface 130 and the projecting lens 114 thus form a third light beam that also contains a horizontal bottom cutoff, located above the second light beam 122.
Similarly to the first embodiment, the sharpness of the horizontal cutoffs depends on the position of the focal point 114.1 of the projecting lens 114. If said focal point is located on the rear edge 120.1 of the second reflective surface 120, or at least in proximity thereto, the cutoff of the second beam 122 will be sharp. If said focal point is located further toward the front, at distance from said rear edge 120.1, the sharpness of the cutoff of the second beam 122 will decrease; in contrast, the sharpness of the cutoff of the third beam 132 will increase as the distance between the focal point and the rear edge 130.1 of the third reflective surface decreases. As already mentioned in relation to the first embodiment, the sharpness of the horizontal cutoffs will also depend on the depth of field of the projecting lens 114.
The convergent optical system 126 comprises a series of convergent lenses, each of which is placed optically between one of the light-emitting regions of the second light source 118 and the corresponding strip of reflective surface 120.3 of the second reflective surface 120.
The third embodiment is similar to the second embodiment and differs therefrom essentially in the absence of the horizontal-top-cutoff-containing first light beam and of the components that produce it. The second and third light beams of the second embodiment then become the first and second light beams of the third embodiment.
Similarly to the first and second embodiments, the sharpness of the horizontal cutoffs depends on the position of the focal point 214.1 of the projecting lens 214. If said focal point is located on the rear edge 220.1 of the first reflective surface 220, or at least in proximity thereto, the cutoff of the first beam 222 will be sharp. If said focal point is located further toward the front, at distance from said rear edge 220.1, the sharpness of the cutoff of the first beam 222 will decrease; in contrast, the sharpness of the cutoff of the second beam 132 will increase as the distance between the focal point and the rear edge 130.1 of the second reflective surface decreases.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR1912908 | Nov 2019 | FR | national |
This application is filed under 35 U.S.C. § 371 U.S. National Phase of International Application No. PCT/EP2020/082607 filed Nov. 18, 2020 (published as WO2021099430), which claims priority benefit to French application No. 1912908 filed on Nov. 19, 2019, the disclosures of which are herein incorporated by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/082607 | 11/18/2020 | WO |
