Lighting device for motor vehicles configured to provide a guidance or maneuvering function.

Abstract

Title. Lighting device (2) for a motor vehicle (1), the lighting device being configured to signal a maneuvering function, the lighting device (2) being characterized in that it comprises: at least one light source (4) configured to produce a monochromatic light beam (F); at least one optical device (14) juxtaposed to the light source (4) such that the light beam (F) passes through the optical device (14), said optical device (14) comprising a metal lens (15) configured to modify at least one property of the wavefront of the light beam (F). Figure for the abstract: Fig. 2

Description

Title of the invention: Luminous device for a motor vehicle configured to provide an orientation or maneuvering function.

[0001] The present invention relates to a lighting device for a motor vehicle, the lighting device being configured to project at least one lighting zone with fixed contours onto and / or in the vicinity of a vehicle for orientation or maneuvering functions. The invention also relates to a motor vehicle equipped with such a lighting device.

[0002] Certain motor vehicles comprise one or more signal lamps which are equipped with one or more lighting devices configured to project at least one lighting zone with fixed contours onto and / or near a vehicle for orientation or maneuvering functions. These lighting zones may comprise images and / or patterns such as arrows, lines or pictograms. Such lighting devices are intended to display useful information to the driver and / or other road users. Publication WO2016184721A1 discloses such a lighting device.

[0003] There are also digital dynamic projection systems such as micro-mirror matrices (called “DMD” in English for “digital micromirror device”), microelectromechanical systems (called “MEMS” in English for “microelectromechanical Systems”), microLEDs, liquid crystal screens or even LCOS video projectors.

[0004] The lighting devices known from the state of the art are generally bulky. In addition, certain lighting devices known from the state of the art comprise relatively fragile components which may become damaged, fail or even break if they are exposed to these shocks or if the motor vehicle is used in a rough environment (damaged, dusty, dirty road or other). Presentation of the invention

[0005] The objective of the present invention is to provide a signaling light equipped with a lighting device for vehicles which overcomes the above drawbacks and improves the lighting devices known from the prior art. In particular, the lighting device according to the invention aims to be light, compact and capable of simply projecting lighting zones with fixed contours onto and / or near the vehicle for orientation or maneuvering functions, in particular providing information going beyond the lighting function.

[0006] Thus, a first object of the invention is a light device that is simple to manufacture and capable of projecting lighting zones with high luminous efficiency to the contours fixed on and / or near the vehicle for orientation or maneuvering functions.

[0007] A second object of the invention is a more compact, more robust and lighter lighting device, easily integrated into a motor vehicle.

[0008] A third object of the invention is a light device which is not affected by possible shocks and / or vibrations generated by the use of the motor vehicle in which said light device is integrated. Summary of the invention

[0009] The invention relates to a light device for a motor vehicle, the light device being configured to signal a maneuvering function, the light device being characterized in that it comprises at least one light source configured to produce a monochromatic light beam and at least one optical device juxtaposed with the light source so that the light beam passes through the optical device, said optical device comprising a meta-lens configured to modify at least one property of the wavefront of the light beam.

[0010] According to a particular embodiment, the light source emits a monochromatic light of orange color having a wavelength between 590 nm and 610 nm.

[0011] According to a particular embodiment, the light source emits a monochromatic light of red color having a wavelength between 620 nm and 700 nm.

[0012] According to a particular embodiment, the light source emits a monochromatic light of cyan color having a wavelength between 490 nm and 500 nm.

[0013] According to a particular embodiment, the light device comprises a projection lens configured to shape the light beam and to direct said light beam towards the ground.

[0014] According to a particular embodiment, the meta-lens of the optical device comprises at least one nanostructure configured to modify the amplitude and / or the phase of the light beam produced by the light source and passing through the optical device so as to influence the orientation of the light beam at the exit of the meta-lens.

[0015] According to a particular embodiment, the nanostructure of the meta-lens is configured to influence the orientation of the light beam at the exit of the meta-lens so that the light device emits a conical-shaped light beam in a projection direction inclined at an angle of between 30° and 90° to the direction of propagation of the light beam produced by the light source.

[0016] According to a particular embodiment, the light device comprises a multitude of light sources and a multitude of meta-lenses, and each light source is associated with a meta-lens which is specific to it.

[0017] According to a particular embodiment, the multitude of meta-lenses is arranged in rows and columns on the optical device so as to form a matrix, and the multitude of light sources is also arranged in rows and columns to form a matrix so that each light beam produced by one of the light sources passes through the meta-lens with which said light source is associated.

[0018] The invention also relates to a motor vehicle equipped with such a lighting device. Presentation of figures

[0019] These objects, characteristics and advantages of the present invention will be explained in detail in the following description of different particular embodiments made without limitation in relation to the attached figures among which:

[0020] [Fig.l] is a schematic view of a motor vehicle equipped with a lighting device according to the state of the art.

[0021] [Fig. 2] is a schematic view of a motor vehicle equipped with a lighting device according to one embodiment of the invention.

[0022] [Fig. 3] is a schematic view of an optical device according to a preferred embodiment of the invention.

[0023] [Fig.4] is a schematic perspective view of a detail of a nanostructure of a meta-lens.

[0024] [Fig.5] is another schematic view of a detail of a nanostructure of a meta-lens.

[0025] [Fig.6] is a schematic perspective view of a meta-lens associated with a variable focal length lens.

[0026] [Fig.7] is a schematic view of a motor vehicle equipped with a lighting device according to one embodiment of the invention. Detailed description

[0027] An embodiment of a motor vehicle 1' according to the invention is described below with reference to [Fig.l].

[0028] The vehicle 1' illustrated schematically in [Fig.l] comprises a light device 2' according to an embodiment known from the state of the art.

[0029] This light device 2' comprises at least one light source 4' capable of produce a light beam F' and a lens matrix 6' intended to be crossed by the light beam F', as well as a light parallelization unit 8'. This light parallelization unit 8' is positioned on the path of the light beam F' between the light source 4' and the lens matrix 6'. The parallelization unit 8' is in the form of a lens which is configured to parallelize the light beam F' emitted by the light source 14' in the main emission direction which is substantially parallel to the optical axes of the microlenses of the matrix 6'.

[0030] The lens matrix 6' comprises a plurality of pairs of microlenses 10' distributed on a flat surface perpendicular to the optical axes of the lenses of this matrix 6'. Each pair of microlenses 10' comprises an upstream microlens and a downstream microlens. By convention, the expression "upstream microlens" designates the microlens through which the light beam F' passes first, while the expression "downstream microlens" designates the microlens through which the light beam F' passes second. In other words, the light beam F' from the light source 4' first passes through the parallelization unit 8', then the microlens upstream of a pair of microlenses 10' arranged within the matrix 6' and finally the microlens downstream of this same pair of microlenses 10'.

[0031] This embodiment of the light device 2' known from the state of the art has several drawbacks. In particular, a large number of microlenses is required to manufacture such a light device 2', which makes it bulky and cumbersome in addition to significantly increasing its weight.

[0032] Furthermore, an optical axis of the downstream microlens must be coaxial with respect to an optical axis of the upstream microlens of the same pair of microlenses 10', which requires great precision when placing the microlenses 10' in the matrix 6', which can prove time-consuming and costly. The risk that this alignment of the optical axes of the microlenses 10' of the same pair is disrupted following vibrations due to the use of the motor vehicle 1' or following an impact on the lighting device 2' is not negligible.

[0033] An embodiment of a motor vehicle 1 according to the invention is described below with reference to [Fig. 2]. Throughout the description, the motor vehicle 1 is a motor vehicle of any type, in particular a passenger vehicle, a utility vehicle, a truck or even a bus.

[0034] This embodiment aims to provide a solution to the problems identified with the known embodiment of the prior art by remedying the drawbacks described above and by proposing an improved lighting device 2. This lighting device 2 is configured to signal an orientation or maneuvering function. It can be, for example, arranged at the front of the vehicle 1, at a grille and / or at the level of headlights intended to illuminate the road and make the vehicle 1 clearly visible to other road users. Alternatively, the lighting device 2 may be arranged on the sides of the motor vehicle 1 or at the rear of said vehicle 1.

[0035] According to one embodiment of the invention, this light device 2 comprises at least one light source 4, for example a light-emitting diode or a set of light-emitting diodes, capable of producing a monochromatic light beam F. The light coming from such a light source 4 only comprises rays of a single wavelength, that is to say that it only comprises light rays having a specific color.

[0036] According to a particular embodiment of the light device 2, the light source emits an orange-colored monochromatic light having a wavelength between 590 nm and 610 nm. According to another embodiment of the light device 2, the light source emits a red-colored monochromatic light having a wavelength between 620 nm and 700 nm. According to yet another embodiment of the light device 2, the light source emits a cyan-colored monochromatic light having a wavelength between 490 nm and 500 nm. In these various embodiments, the light device is for example configured to project one or more bands of colored light around the vehicle to inform the driver of his margin of mobility for a maneuver.

[0037] Advantageously, the light source 4 may have sufficient power to signal an orientation or maneuvering function that is visible even in broad daylight. The light source 4 may be connected to a printed circuit board 6. The printed circuit board 6 may be held by a support 7 possibly comprising a heat sink.

[0038] The light device 2 also comprises at least one optical device 14 juxtaposed with the light source 4 so that the light beam F produced by the light source 4 passes through the optical device 14. In addition, the optical device 14 comprises at least one meta-lens 15 configured to modify at least one optical property of the wavefront of the light beam F produced by the light source 4.

[0039] Thus, the transmission rate through an optical device 14 comprising a meta-lens 15 with a monochromatic light beam F is for example greater than 75% and in particular greater than 80%, or even higher. This gives a brighter image and / or it is possible to use a lower power light source and / or one that consumes less energy.

[0040] The at least one meta-lens 15 may have an elliptical shape, in particular a circular shape, or a polygonal shape, in particular a quadrilateral shape. According to a particular embodiment, the meta-lens(es) 15 may have a square or rectangular shape. According to a preferred embodiment illustrated in [Fig. 3], the meta-lens(es) 15 of the optical device 14 may have a diamond shape. Such shapes, in particular the diamond shape as illustrated in [Fig. 3], may allow a compact matrix arrangement of several meta-lenses 15.

[0041] The meta-lens 15 of the optical device 14 generally comprises a nanostructure 16 configured to modify the shape of the wavefront of the light beam F produced by the light source 4 and passing through the optical device 14, and more particularly to modify the amplitude and therefore the intensity and / or the phase and therefore the direction of propagation of the light beam F.

[0042] The nanostructure 16 of the meta-lens 15 may comprise an arrangement of nanopillars 17 on its surface. These nanopillars 17 are generally manufactured by nanostructuring, i.e. by electron beam lithography or by nanoimprint lithography in thin layers and arranged in the form of periodic networks. These nanopillars 17 of nanometric size may comprise dielectric materials with a high refractive index, for example a refractive index greater than two.

[0043] More particularly, the nanostructure 16 may comprise a periodic array of nanopillars 17. By “periodic” is meant here that the nanopillars within the nanostructure 16 are placed at more or less regular intervals from one another. For example, the nanopillars 17 of a nanostructure 16 may be placed at intervals of between 300 nm and 500 nm with a preference for an interval of 400 nm. In other words, the centers of two neighboring nanopillars 17 are 400 nm apart.

[0044] The optical properties of a meta-lens 15 are mainly defined by the wavelength of the monochromatic light source used, by the refractive index(es) of the materials used for the nanopillars 17, by the dimensions of the nanopillars 17 and by their distribution within the nanostructure 16. In other words, the density of material in the nanostructure 16 of the meta-lens 15 defines the effect that the meta-lens 15 has on the light beam F which passes through it.

[0045] The nanopillars 17 are for example placed on a transparent substrate. The material of the transparent substrate is chosen to provide suitable structural support and to allow a majority of the light passing through it to pass through. Such material substrates include for example fused silica, borosilicate glass or even glasses based on rare earth oxides.

[0046] In one embodiment, the substrate has a first refractive index ni and the nanopillars 17 have a second refractive index n2. The first refractive index ni of the substrate is lower than the second refractive index n2 of the nanopillars 17. These refractive indices ni and n2 also have an influence on the light beam F which passes through the nanopillars 17 of the nanostructure 16 of the meta-lens 15 and therefore make it possible to modify at least one of the properties of the wavefront.

[0047] Generally, the nanopillars 17 may have sections of different sizes from one another. Indeed, the shape and size of the section of a nanopillar 17 of the nanostructure 16 has an impact on the propagation speed of the light beam F which passes through said nanopillar 17, thus modifying the optical properties of the wavefront of said light beam F which passes through the optical device 14.

[0048] The nanopillars 17 may in particular have a cylindrical shape; in this case, they may comprise a base of circular shape, as illustrated in [Fig. 4]. The diameter may vary from one nanopillar 17 to another. An example of an arrangement of nanopillars 17 of cylindrical shape with a determined height and different diameters is illustrated in [Fig. 4]. Alternatively, the shape of the base could be different from a circular shape, for example a polygonal base, in particular square or rectangular.

[0049] Furthermore, these nanopillars 17 may have the same height configured to modify the phase of the light beam F produced by the light source 4. For monochromatic light having a given wavelength, the ideal height of the nanopillars 17 may be determined to obtain the highest possible transmission rate. The height of the nanopillars 17 makes it possible to control the phase between 0 and 2ir.

[0050] By way of example, and according to a preferred embodiment, the light source 4 can be configured to emit a light beam with a wavelength equal to 590 nm. In this particular example, the refractive index n1 of the material used for the substrate is equal to 1.52 while the refractive index n2 for the nanopillars is equal to 2.36. Still in this particular example, the height of the nanopillars 17 is 600 nm and the diameter of the nanopillars 17 can be between 50 nm and 150 nm.

[0051] The distribution of the nanopillars 17 within the nanostructure 16 of the meta-lens 15 can be optimized to contribute to a change in the direction of propagation of the light beam. In other words, the distribution of the nanopillars 17 within the nanostructure 16 can be specifically configured to influence the direction of propagation of the light beam F in order to modify the orientation of the light beam at the exit of the meta-lens 15.

[0052] More generally, a meta-lens 15 comprises a periodic array of nanopillars 17 having different diameters so as to influence the speed of propagation of light through the nanopillars 17 so as to modify the properties of the wavefront of the light beam F which passes through the meta-lens 15. Indeed, for two nanopillars 17 having the same height and different diameters, the nanopillar with a larger diameter will slow down the propagation of the light passing through it more than the nanopillar with a smaller diameter. This is notably illustrated in [Fig.5].

[0053] In this way, the nanostructure 16 of the meta-lens 15 can be configured to influence the orientation of the light beam F at the exit of the meta-lens 15 so that the light device 2 emits a light beam F of conical shape in a projection direction inclined at an angle of between 30° and 90° relative to the direction of propagation of the light beam F produced by the light source 4.

[0054] Furthermore, the arrangement of the nanopillars 17 in the nanostructure 16 of the meta-lens 15 may be configured so that the latter has a structure suitable for projecting at least one lighting zone with fixed contours onto and / or near the vehicle 1 for orientation or maneuvering functions. The geometric pattern of the projected image preferably has a simple geometric shape. It may for example be an arrow indicating a direction, as illustrated in [Fig.7], or a pictogram or a set of shapes and / or bands and / or lines.

[0055] According to a preferred embodiment, the light device 2 comprises a multitude of light sources 4 and a multitude of meta-lenses 15. In this preferred embodiment, the light device 2 therefore comprises as many meta-lenses 15 as light sources 4 and each light source 4 is associated with a meta-lens 15 which is specific to it. The light sources 4 may be identical to each other or different from each other. In the latter case, each light source 4 may for example have a different wavelength, and be associated with a meta-lens 15 designed for this type of monochromatic wavelength source, to thus emit a dynamic and unique optical waveform.

[0056] In this same embodiment, the multitude of meta-lenses 15 is arranged in rows and columns within the optical device 14 so as to form a matrix. The multitude of light sources 4 is also arranged in rows and columns so as to form a matrix. The multitude of meta-lenses 15 and the multitude of light sources 4 are arranged relative to each other so that each light beam F produced by one of the light sources 4 passes through the meta-lens 15 with which said light source 4 is associated. Thus, each meta-lens 15 is passed through by the light beam F produced specifically by the light source 4 with which the meta-lens 15 is associated.

[0057] Such a matrix arrangement of the light sources 4 and the meta-lenses 15 associated with said light sources 4 may prove to be more compact than in the case of the device known from the state of the art. In other words, such a matrix arrangement of certain components of the lighting device 2 can contribute to the overall compactness of said lighting device 2.

[0058] Advantageously, the light sources 4 can be switched on or off in the desired order, which has the consequence that the light beams F from said light sources 4 pass through the meta-lenses 15 with which they are associated in the order of activations and deactivations of the light sources 4. Thus, the order does not depend on the arrangement of the meta-lenses 15 within the optical device 14, which can offer more diversity and / or simplicity in the signaling of an orientation or maneuvering function. It is in particular possible to switch on several light sources 4 at the same time and therefore to carry out a more complex and information-rich signaling of an orientation or maneuvering function around the motor vehicle 1.

[0059] According to a particular embodiment, a liquid crystal layer 18 and a voltage source 19 adapted to control an electric field passing through the liquid crystal layer 18 can be associated with the meta-lens 15 to form a variable focal length lens thanks to the phase change of the liquid crystals 18, as illustrated in [Fig. 6]. This variable focal length lens is arranged on the path of the light beam F produced by the at least one light source 4. The liquid crystal layer 18 comprises a set of liquid crystals whose orientation can be controlled by means of the electric field applied to it. Such a variable focal length lens therefore makes it possible to adapt the focal length f1, f2 according to the location of the light device 2 relative to the surfaces around the motor vehicle 100 on which the light zone(s) are projected.Advantageously, each meta-lens 15 of the previously described matrix is ​​associated with an individually controllable liquid crystal layer 18. Thus, the light device 2 can produce a plurality of light beams, each light beam having its own focal length.

[0060] It is also possible to use a projection lens in order to shape the light beam F and to orient it in a desired direction. In general, a projection lens is capable of shaping a light beam in a defined spatial field so that said light beam F is projected in accordance with the functions that the lighting device 2 must fulfill. In other words, a projection lens makes it possible to define the shape of the light beam at the end of the lighting device 2. Thus, a projection lens can make it possible to define the width and / or the height of the light beam F, as well as its length, that is to say up to what distance the light beam F can illuminate, and / or its angle of inclination. Such a projection lens can in particular be configured to directing said light beam F towards the ground so as to project a light image onto the ground near the motor vehicle, as illustrated in [Fig.7].

[0061] It is therefore possible to design a more compact and lighter lighting device 2 which can be easily integrated into a motor vehicle 1. Such a lighting device 2 is capable of simply projecting lighting zones with fixed contours onto and / or near the vehicle 1 for orientation or maneuvering functions. Such a lighting device 2 according to the invention is not or only slightly affected by possible shocks and / or vibrations generated by the use of the motor vehicle 1 in which said lighting device 2 is integrated and demonstrates better thermal performance. Thus, a lighting device 2 according to the invention therefore offers a more robust and more reliable alternative than the lighting devices 2' known from the state of the art.

Claims

Claims

1. Lighting device (2) for a motor vehicle (1), the lighting device being configured to signal a maneuvering function, the lighting device (2) being characterized in that it comprises: • at least one light source (4) configured to produce a monochromatic light beam (F); • at least one optical device (14) juxtaposed with the light source (4) so ​​that the light beam (F) passes through the optical device (14), said optical device (14) comprising a meta-lens (15) configured to modify at least one property of the wavefront of the light beam (F).

2. A light device (2) according to claim 1, characterized in that the light source (4) emits a monochromatic orange-colored light having a wavelength between 590nm and 610nm.

3. Luminous device (2) according to claim 1, characterized in that the light source (4) emits a monochromatic light of red color having a wavelength between 620 nm and 700 nm.

4. A light device (2) according to claim 1, characterized in that the light source (4) emits a monochromatic light of cyan color having a wavelength between 490 nm and 500 nm.

5. Lighting device (2) according to one of the preceding claims, characterized in that it comprises a projection lens configured to shape the light beam (F) and to direct said light beam (F) towards the ground.

6. Luminous device (2) according to one of the preceding claims, characterized in that the meta-lens (15) of the optical device (14) comprises at least one nanostructure (16) configured to modify the amplitude and / or the phase of the light beam (F) produced by the light source (4) and passing through the optical device so as to influence the orientation of the light beam (F) at the exit of the meta-lens (15).

7. Luminous device (2) according to the preceding claim, characterized in that the nanostructure (16) of the meta-lens (15) is configured to influence the orientation of the light beam (F) at the exit of the meta-lens (15) so that the luminous device (2) emits a light beam (F) of conical shape in a projection direction inclined at an angle of between 30° and 90° relative to the direction of propagation of the light beam (F) produced by the light source (4).

8. Luminous device (2) according to one of the preceding claims, characterized in that it comprises a multitude of light sources (4) and a multitude of meta-lenses (15), and in that each light source (4) is associated with a meta-lens (15) which is specific to it.

9. Luminous device (2) according to the preceding claim, characterized in that the multitude of meta-lenses (15) is arranged in rows and columns on the optical device (14) so ​​as to form a matrix, and in that the multitude of light sources (4) is also arranged in rows and columns to form a matrix so that each light beam (F) produced by one of the light sources (4) passes through the meta-lens (15) with which said light source (4) is associated.

10. Motor vehicle characterized in that it comprises a light device (2) according to one of the preceding claims.

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