The invention relates to the field of lighting, in particular lighting for a motor vehicle.
The night-time lighting function of a motor vehicle with traffic coming in the opposite direction, normally called low beam, has an upper cut-off in accordance with applicable regulations. European regulations however require an upper horizontal cut-off with an oblique portion to the centre of the beam, such that a left or right half of the light beam has a lower horizontal cut-off than the other half. More particularly, for countries which drive on the right, i.e. where the driving controls are on the left of the vehicle, the left half of the light beam is lower than the right half. Conversely, for countries which drive on the left, i.e. where the driving controls are on the right of the vehicle, the left half of the light beam is higher than the right half. American regulations however require in particular a flat upper horizontal cut-off, i.e. without oblique portion. This means that motor vehicle headlights must be configured differently according to territory.
Published patent document US 2018180246 A1 discloses a motor vehicle headlight comprising a screen which is arranged in the optical path of the light rays, forming a light beam with cut-off, and the transmittance of which is variable locally, such as for example a liquid crystal display (LCD). More particularly, the pixels of this screen can be controlled specifically to create the above-mentioned horizontal cut-offs for driving on the left and driving on the right respectively, i.e. with opposing central oblique portions. In other words, this teaching provides a configuration by electrical control of the headlight for different regulations, in particular for driving on the left and driving on the right. However, the presence of the screen with locally variable transmittance is costly and also has the drawback of generating significant light losses due to the limited maximum transmittance.
The object of the invention is a lighting module, in particular for a motor vehicle, comprising a main optical system able to form a main light beam along an optical axis of the lighting module, with an upper horizontal cut-off; a first complementary optical system able to form a first complementary light beam along the optical axis, narrower than the main light beam and with an oblique lateral cut-off; which is distinguished in that the lighting module also comprises a second complementary optical system able to form an alternative, second complementary light beam along the optical axis, narrower than the main light beam and with an oblique lateral cut-off opposite the oblique lateral cut-off of the first light beam.
The main light beam combined with the first complementary light beam corresponds to a lighting function with cut-off with addition for driving on the right. The main light beam combined with the second complementary light beam corresponds to a lighting function with cut-off with addition for driving on the left.
According to an advantageous embodiment of the invention, the oblique lateral cut-offs of the first and second complementary light beams are adjacent to the optical axis, the first complementary light beam extending exclusively to the right of said optical axis and the second complementary light beam extending exclusively to the left of said optical axis.
According to an advantageous embodiment of the invention, the lighting module is configured such that the first and second optical systems are only active alternatively.
According to an advantageous embodiment of the invention, each of the first and second complementary light beams also has an upper horizontal cut-off and/or a lower horizontal cut-off.
According to an advantageous embodiment of the invention, each of the first and second complementary optical systems comprises a light source and an optical element with a surface able to be illuminated by said light source, and the lighting module comprises a device for projecting the first and second complementary light beams, which is configured to form an image of the illuminated surface of the optical element of each of the first and second complementary optical systems.
According to an advantageous embodiment of the invention, the surfaces able to be illuminated of the first and second complementary optical systems are arranged laterally on either side of the optical axis.
According to an advantageous embodiment of the invention, the surfaces able to be illuminated of the first and second complementary optical systems are arranged below the optical axis.
According to an advantageous embodiment of the invention, each of the surfaces able to be illuminated of the first and second complementary optical systems has a mean height H and a mean width L greater than 5 times said mean height H.
According to an advantageous embodiment of the invention, each of the surfaces able to be illuminated of the first and second complementary optical systems comprises an inclined lateral edge able to form the oblique lateral cut-off of the corresponding complementary light beam.
According to an advantageous embodiment of the invention, the inclined lateral edges of the surfaces able to be illuminated of the first and second complementary optical systems are adjacent to the optical axis and arranged laterally on either side of said optical axis.
According to an advantageous embodiment of the invention, the optical element of each of the first and second complementary optical systems is a diopter with a face for inlet of the light emitted by the corresponding light source, a face for reflecting said light, and a face for outlet of said light, forming the surface able to be illuminated.
According to an advantageous embodiment of the invention, the optical element of each of the first and second complementary optical systems comprises a reflective surface forming the surface able to be illuminated.
According to an advantageous embodiment of the invention, the main optical system comprises a light source with a main direction of emission of light beams which is directed upward, and a collector with a reflective surface in the form of a cap able to receive the light beams and with a lower rear edge adjacent to the optical axis.
According to an advantageous embodiment of the invention, the surfaces able to be illuminated of the first and second complementary optical systems are adjacent to the lower rear edge of the reflective surface of the collector at the optical axis.
According to an advantageous embodiment of the invention, the projection device comprises a focal point situated on the optical axis at the level of the lower rear edge of the reflective surface of the collector or in front of said edge.
The measures of the invention are useful in that they allow creation of a lighting module with a lighting function with upper horizontal cut-off of the low beam type, which is compatible with different regulations and driving sides (driving on the left and driving on the right), in a simple, economic and compact manner.
In the description below, the terms “front” and “rear” should be understood following the optical axis of the lighting module in the normal direction of propagation of the light rays. Similarly, the terms “top”, “bottom”, “horizontal” and “vertical” should be understood when the lighting module is in the operational position, as illustrated in particular in
The lighting module 2 comprises several optical systems able to form different light beams of one or more lighting functions, in this case a lighting function with upper horizontal cut-off, normally known as low beam, and a lighting function without horizontal cut-off, normally known as high beam. The lighting module 2 comprises a main optical system 4 able to form a main light beam with upper horizontal cut-off, intended to implement a low-beam lighting function. The main optical system 4 essentially comprises a light source 6 and a collector 8 with a reflective surface in the form of a cap, and configured to receive the light rays emitted by said light source and reflect these along the optical axis 10. The lighting module 2 also comprises two complementary optical systems 12 and 14, arranged below the optical axis 10 and configured to form, in an alternative fashion, light beams which are complementary to the main light beam formed by the main optical system 4. Each of these complementary optical systems 12 and 14 substantially comprises a respective light source 16 or 18 and a respective optical element 20.1 or 20.2. In this case, the optical elements 20.1 and 20.2 are unitary and form a common optical element 20. Each of the complementary light beams formed by the complementary optical systems 12 and 14 complements the main light beam by forming an addition at the level of the horizontal cut-off in accordance with regulations in force, in particular in Europe. In practice, the first complementary optical system 12 forms a complementary light beam situated to the right of the optical axis with an oblique lateral cut-off adjacent to the optical axis, so as to form an upward addition to right of the optical axis in accordance with regulations for driving on the right. Similarly, the second complementary optical system 14 forms a complementary light beam situated to the left of the optical axis with an oblique lateral cut-off adjacent to the optical axis, so as to form an upward addition to the left of the optical axis in accordance with regulations for driving on the left.
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In the main optical system 4, it is noted that the light source 6 illuminates the reflective surface of the collector 8 from the lower rear edge 8.1 up to the front edge 8.2 of said reflective surface. The projection device 22 comprises a focal point 22.1 situated on the optical axis 10 level with the lower rear edge of 8.1, or a position slightly further forward but still at the level of the collector 8, ideally on a first half of the length of the collector along the optical axis. By means of a certain field depth, this allows the projection device 22 to image the reflective surface of the collector 8 when illuminated, where the zone of the reflective surface along the lower rear edge 8.1 is imaged with clarity so as to achieve a clear upper horizontal cut-off. In order to image the illuminated reflective surface, the main optical system 4 including the projection device 22 must be stigmatic. A rigorous stigmatism is present when, for two points, the set of light rays emitted from one of the points and passing through the system forms other light rays, the supports of which pass through the second point. In practice, this would be rather an approximate stigmatism obtained in particular by existing in Gaussian conditions. These conditions provide that the angles of incidence of the rays relative to the optical axis of the element are low, typically less than or equal to 20°, and/or that the point of incidence is close to the optical axis. To this end, the optical device 22 advantageously has a large focal distance, more advantageously also a large geometric aperture. For example, the focal distance is more than 40 mm, preferably more than 50 mm, more preferably more than 60 mm. The focal distance is advantageously less than 100 mm.
For the complementary optical system 12 or 14, we see the path of the rays emitted by the corresponding light source 16 or 18. These are potentially refracted in the diopter formed by the inlet face 20.1.1 or 20.2.1, then reflected by the reflective face 20.1.2 or 20.2.2, advantageously by the principle of total reflection when the angle of incidence is greater than the limit angle of refraction, and then potentially refracted on passage through the diopter formed by the outlet face 20.1.3 or 20.2.3 which then forms an illuminated surface. This illuminated surface is advantageously adjacent to the optical axis 10 and to the lower rear edge 8.1 of the reflective surface of the collector 8. Therefore, the illuminated surface 20.1.3 or 20.2.3 is adjacent to the focal point 22.2 of the projection device 22, or at least close to this. This illuminated surface is then imaged with clarity which allow creation of a complementary light beam with clear cut-offs.
The image of the main light beam 26 comprises an upper horizontal cut-off 26.1 which is generally flat or straight. It is formed by the image of the lower rear edge 8.1 of the reflective surface of the collector 8 of the main optical system 4 (
The image of the first complementary light beam 28 situated to the right of the optical axis 10 (at the intersection of the axes H and V) is produced by the first complementary optical system 12 (
The combination of the main light beam 28 with the first complementary light beam 28 corresponds to a lighting function known as low beam for driving on the right in accordance with regulations in force in Europe in particular. Similarly, the combination of the main light beam 26 with the second complementary light beam 30 corresponds to a lighting function known as low beam for driving on the left in accordance with the same regulations. The main light beam 26 alone may correspond to a lighting function known as low beam in accordance with regulations in force in the United States of America.
The collector 108 of the main optical system 104 comprises a reflective surface in the form of a cap with a lower rear edge 108.1 adjacent to the optical axis 110, and a front edge 108.2 which corresponds in this case to a truncation of the cap by an upper plane close to a horizontal orientation. The light source 106 is configured to illuminate this reflective surface, which is imaged by the projection device 122 (
In general, i.e. in particular for the two embodiments, the light source of the main optical system and the light sources of the complementary optical systems may be arranged on a common support because of their proximity and the fact that they all emit light in the same direction.
In view of the above, it will be understood that the complementary optical systems may take various forms, provided that they are configured to form alternative complementary light beams with opposite oblique lateral cut-offs which, together with the main light beam with upper horizontal cut-off of advantageously flat profile, are able to form an upper horizontal cut-off with an addition in the centre in accordance with regulations in force in Europe in particular.
In view of the above, it will also be understood that the main optical system may also take various forms insofar as it produces a light beam with upper horizontal cut-off which is advantageously flat.
The invention which has just been described is advantageous in that it allows production of a single lighting module for a low beam lighting function which is compatible with various regulations, such as European regulations, with a specific addition for driving on the left and for driving on the right, and American regulations without addition. Conformity with the regulations to be observed is then achieved by specific activation of one or neither complementary optical system.
Number | Date | Country | Kind |
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1912144 | Oct 2019 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2020/078940 | 10/14/2020 | WO |