Luminous device comprising an array of mini-light sources, an array of micro-lenses and an array of meta-lenses

Abstract

The invention relates to a luminous device (1) comprising: - a first array (10) of light sources (100) for emitting light (R) forming a light beam (Fx); characterised in that the light sources (100) are mini-light sources (100), and in that the luminous device (1) comprises: - a second array (11) of micro-lenses (111) comprising pairs (p) of micro-lenses (111), each pair (p) being placed facing one light source (100) with a view to collimating the light (R) so as to create a collimated sub-beam (f); - a third array (12) of meta-lenses (121) for forming an overall light beam (Fx') and comprising a plurality of meta-lenses (121), each meta-lens (121) being placed facing each pair (p) of micro-lenses (111) so as to orient the collimated sub-beam (f) and form it into the form of a luminous segment (s) of the overall light beam (Fx').

Description

A lighting device comprising an array of mini light sources, an array of microlenses, and an array of metal lenses.

[0001] The present invention relates to a lighting device for vehicles. The invention also relates to a vehicle headlight comprising such a lighting device. It finds particular, but not limiting, application in motor vehicles.

[0002] In the field of motor vehicles, a lighting device known to those skilled in the art comprises: - a plurality of light sources configured to emit light, - several rod-shaped light guides arranged opposite the plurality of light sources, - a projection optic with one or more lenses arranged in front of the light guides.

[0003] The light sources have an emitter approximately 700 micrometers on each side, or 0.5mm 2of surface. The lighting device generates a light beam in the form of segments to perform a road-type photometric function and a code-type photometric function. Each segment is illuminated by activating a corresponding light source.

[0004] One drawback of this state of the art is that the lighting device is bulky.

[0005] In this context, the present invention aims to provide a lighting device that solves the aforementioned problem.

[0006] To this end, the invention proposes a vehicle lighting device comprising: - a first matrix of light sources configured to emit light forming an incoming light beam; characterized in that the light sources are mini-light sources, and in that said lighting device further comprises: - a second matrix of micro-lenses comprising a plurality of pairs of micro-lenses, each pair being arranged opposite a light source and configured to collimate said light so as to create a collimated sub-beam;- a third array of meta-lenses configured to form an overall light beam and comprising a plurality of meta-lenses, each meta-lens being arranged opposite each pair of micro-lenses and being configured to orient the collimated sub-beam of said pair and to form it in the form of a luminous segment or part of a luminous segment composing said overall light beam.;

[0007] Thus, as we will see below, replacing large light sources, light guides and projection optics with a matrix of mini light sources, a matrix of micro-lenses and a matrix of meta-lenses makes it possible to greatly reduce the size in the depth direction of the lighting device.

[0008] According to non-limiting embodiments, the vehicle lighting device may further comprise one or more additional features taken alone or in all technically possible combinations, from among the following.

[0009] According to a non-limiting embodiment, in that the light sources include an emitter with a size between 100 and 200 micrometers on each side.

[0010] According to a non-limiting embodiment, a micro-lens has a side between 0.5 and 2 millimeters.

[0011] According to a non-limiting embodiment, said metal lenses have a surface area less than or equal to 1 mm² 2 .

[0012] According to a non-limiting embodiment, the light sources have a size less than or equal to a first step defined between two adjacent microlenses.

[0013] According to a non-limiting embodiment, the meta-lenses have a size less than or equal to a first step defined between two adjacent micro-lenses.

[0014] According to a non-limiting embodiment, said first step is between 0.5 and 2 millimeters.

[0015] According to a non-limiting embodiment, the meta-lenses of the third matrix comprise nano-pillars defined by a radius, a height and a second pitch between two nano-pillars.

[0016] According to a non-limiting embodiment, said nano-pillars are made of Silicon Nitride.

[0017] According to a non-limiting embodiment, said nano-pillars have different radii and the same height.

[0018] According to a non-limiting embodiment, the light sources are semiconductor light sources or laser sources.

[0019] According to a non-limiting embodiment, the light sources can be activated independently of each other.

[0020] According to a non-limiting embodiment, each light source is traversed by a current whose intensity is controllable independently of the other light sources.

[0021] According to a non-limiting embodiment, the surface area of ​​the light sources is less than 4mm 2 According to a non-limiting embodiment, the surface area is less than 0.25 mm 2 .

[0022] A vehicle projector is also proposed, characterized in that said projector comprises: - said lighting device according to the invention; - a control device for the first matrix of light sources, said control device being configured to activate different light sources of said first matrix, and said lighting device being configured to perform at least one of the following photometric functions: - a rotating low beam photometric function, - a rotating high beam photometric function, - a glare-free high beam photometric function.

[0023] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures:

[0024] Laillustrate very schematically a lighting device for a vehicle according to a non-limiting embodiment of the invention, said lighting device comprising a first matrix of mini light sources, a second matrix of micro-lenses, and a third matrix of meta-lenses;

[0025] Laest is a representation of a meta-lens of the third matrix of laaccording to a non-limiting embodiment, the meta-lens comprising a substrate and nano-pillars;

[0026] Laillustre an enlarged view of a plurality of nano-pillars of the meta-lens according to a non-limiting embodiment,

[0027] Laillustre shows a highly magnified view of a single nano-pillar of the meta-lens with a portion of the substrate,

[0028] The illustration of the nano-pillars of the meta-lens and the direction of propagation of light emitted by a light source from the first matrix of the lens when it passes through said nano-pillars,

[0029] Laillustre a first curve indicating a phase variation as a function of the radius of a nano-pillar of a meta-lens of the third meta-lens matrix of the,

[0030] Laillustre a second curve showing a variation in light transmission as a function of the radius of a nano-pillar of a meta-lens of the third meta-lens array of the,

[0031] Laillustrates a global light beam composed of segments, said segments being formed by the third metal-lens matrix of the, said global light beam performing a rotating-code photometric function,

[0032] Laillustrates a global light beam composed of segments, said segments being formed by the third metal-lens matrix of the, said global light beam performing a rotating road photometric function,

[0033] Laillustrates a global light beam composed of segments, said segments being formed by the third metal-lens matrix of the, said global light beam performing a glare-free photometric road function,

[0034] The illustration is very schematically a vehicle projector according to a non-limiting embodiment, said projector comprising said light device and a control device for the first matrix of mini light sources.

[0035] Identical elements, whether structural or functional, appearing on different figures retain the same references unless otherwise specified.

[0036] The vehicle lighting device 1 according to the invention is described with reference to figures 1 to 11.

[0037] In a non-limiting embodiment, the lighting device 1 is a lighting device of a vehicle 2 (illustrated in the figure). In a non-limiting embodiment, the vehicle 2 is a motor vehicle. A motor vehicle is defined as any type of motorized vehicle. This embodiment is taken as a non-limiting example in the following description. In the following description, the vehicle 2 is thus also referred to as motor vehicle 2. In a non-limiting variant of the embodiment, the vehicle 2 is a combustion engine, electric, or hybrid vehicle.

[0038] The light device 1 is part of a projector 3 (illustrated on the) of the vehicle 2. In a non-limiting embodiment, the projector 3 is configured to perform at least one of the following photometric functions: - a rotating code photometric function referenced LB_B and called "Low Beam Bending" in English, - a rotating road photometric function referenced HB_B and called "High Beam Bending" in English, - a glare-free road photometric function referenced ADB and called "Adaptive Bending Light" in English.

[0039] As illustrated on the figure, the light device 1 comprises: - a first matrix 10 of light sources 100, - a second matrix 11 of micro-lenses 111, and - a third matrix 12 of meta-lenses 121.

[0040] In the following description, the first matrix 10, the second matrix 11, and the third matrix 13 are otherwise referred to respectively as matrix 10, matrix 11, and matrix 12. These three matrices are described in detail below.

[0041] The first matrix of 10 light sources is described below.

[0042] As illustrated on the, the light sources 100 of the first matrix 10 are configured to emit R light. For clarity, only two light sources 100 have been referenced on the and using the same reference 100 for simplification as well.

[0043] The set of lights R emitted by the light sources 100 forms an incoming light beam Fx. In a non-limiting embodiment, the light source 10 is an RGB source.

[0044] Light sources 100 are mini light sources. In the following description, they are also referred to as mini light sources 10. They comprise an emitter with a side size between 100 and 200 micrometers (µm). By "mini," we mean that their surface area (emitter alone) is less than 4 mm². 2 In a non-limiting example, the surface area is less than 0.25mm 2 . They thus have a dimension compatible with the matrix 11 of micro-lenses 111 and the matrix 12 of meta-lenses 121.

[0045] In one non-limiting embodiment, the light sources 100 are semiconductor light sources. In other non-limiting embodiments, the semiconductor light sources are light-emitting diodes (LEDs) or laser diodes. Light-emitting diode (LED) is understood to mean any type of LED, including, but not limited to, LEDs (Light Emitting Diodes), OLEDs (Organic LEDs), AMOLEDs (Active-Matrix Organic LEDs), and FOLEDs (Flexible OLEDs). In another non-limiting embodiment, the light sources 100 are laser light sources. It should be noted that some laser light sources are not semiconductor light sources.

[0046] In a non-limiting embodiment, the light sources 100 are arranged in rows and columns on a substrate (not shown) to form the first matrix 10. In a non-limiting embodiment, the substrate is an electronic support such as, in a non-limiting example, a printed circuit board known as a PCB, with suitable tracks and contacts.

[0047] In a non-limiting embodiment, the light sources 100 can be activated independently of each other. Thus, each light segment s (described later) of the overall light beam Fx' produced by the light device 1 can be switched on or off. In the following description, the overall light beam Fx' is referred to as the emerging light beam Fx'. The overall light beam Fx' is white and complies with current regulations for spotlights. In the following description, a light segment s is referred to as segment s.

[0048] In a non-limiting embodiment, each light source 100 carries a current i whose intensity I is controllable independently of the other light sources (100) so as to control its luminous flux. This makes it possible to control the luminous power of each segment s obtained from an assembly of light source(s) 100, pair(s) p of microlenses 111 and metal lens(es) 121.

[0049] The ability to address the 100 light sources independently and to control the intensity I of the current i flowing through them allows us to obtain light segments s with varying luminous fluxes, which are either illuminated or not. This enables motion simulation to implement the functions of turning code LB, turning route HB, and glare-free route ADB with different luminous intensities in the overall light beam Fx', as will be seen later.

[0050] As illustrated in Figure 1, each light source 100 is positioned opposite a pair p of microlenses 111 such that the emitted light R enters the pair p of microlenses 111. Thus, a light source 100 illuminates a precise area of ​​the array 11 of microlenses 111. For clarity, only two pairs p of microlenses 111 have been referenced in Figure 1, using the same reference numeral 111 for simplification. Each light source 100 is therefore in bijection with a pair p of microlenses 111 and a metalens 121 so that it can individually switch on or off each light segment s of the overall light beam Fx'.

[0051] In a non-limiting embodiment, the light sources 100 have a size (emitter and housing included) less than or equal to a first step size ps (illustrated in the figure) defined between two adjacent microlenses 111 of two different adjacent pairs p. This allows for efficient illumination of the pair p of microlenses 111. The first step size ps is defined, in particular, between the two optical axes of two adjacent microlenses 111. In a non-limiting embodiment, the step size ps is between 0.5 and 2 mm. Thus, in a non-limiting embodiment, the size of the light sources 100 is less than or equal to 4 mm². In a non-limiting variant, the size is less than or equal to 0.25 mm².

[0052] The second matrix 11 of microlenses 111 is described below.

[0053] The second microlens array 111 enables the collimation of light. It should be noted that the second array 11 is positioned between the first array 10 and the third array 12. The second array 11 is a matrix known by the acronym MLA, for "Matrix Lens Array."

[0054] In a non-limiting embodiment, the microlenses 111 are arranged in rows and columns to form the second matrix 11. In a first non-limiting embodiment variant, a common core of an injected part allows for a single transparent substrate to be used to fabricate all the microlenses 111. In a second non-limiting embodiment variant, the microlenses 111 are bonded together to form the second matrix 11.

[0055] The second microlens array 11 of microlenses 111 comprises a plurality of pairs p of microlenses 111. A pair p (or pair p) comprises an input microlens 111 and an output microlens 111. In a non-limiting embodiment, each microlens 111 of pair p has a side length between 0.5 and 2 mm, thus having a surface area between 0.25 mm² and 4 mm². In a non-limiting variant of the embodiment, pair p has a side length of 1 mm². 2 of surface. Thus, in a non-limiting embodiment, a micro-lens 111 has a side between 0.5 and 2 mm. Its size is adapted to the size of a mini light source 100.

[0056] Each pair p of microlenses 111 is configured to receive the light R emitted by a light source 100. One pair p is thus positioned opposite a light source 100 and is configured to collimate this light R so as to create a collimated sub-beam f illustrated in the figure. Each collimated sub-beam f thus constitutes a substantially plane wave with respect to the associated meta-lens 121 (described later).

[0057] In a non-limiting example, the first pitch ps between two adjacent microlenses 111 is equal to the size of a microlens 111, therefore between 0.5 and 2 mm. In a non-limiting embodiment, the mini light sources 10 are spaced with the same pitch ps as the microlens array 11, and therefore their dimensions are less than or equal to this pitch ps as described previously. In a non-limiting variant of the embodiment, for fit tolerances, their dimensions are smaller than this pitch ps.

[0058] The third matrix 12 of meta-lenses 121 is described below.

[0059] The third matrix 12 of meta-lenses 121 is configured to form an overall light beam Fx' composed of a plurality of light segments s (also called s segments). The third matrix 12 comprises a plurality of meta-lenses 121. The overall light beam Fx' is projected to the side of the vehicle direction Ox as illustrated in the figure. Note that the third matrix 12 is arranged on one side of the second matrix 11 opposite the side to which the first matrix 10 is arranged.

[0060] In a non-limiting embodiment, the meta-lenses 121 are arranged in rows and columns to form the third matrix 12. In a first non-limiting embodiment, the meta-lenses 111 are arranged on a common substrate, namely, there is a common substrate with different fields of nano-pillars 121.2 (described later). In a second non-limiting embodiment, the meta-lenses 121 are bonded to an additional common transparent substrate, namely, each field of nano-pillars 121.2 and their substrate 121.1 (described later) is bonded to the additional transparent substrate.

[0061] Each meta-lens 121 of the third matrix 12 is arranged opposite each pair p of micro-lenses 111 and is configured to: - orient the collimated sub-beam f of said pair p, and - form the collimated sub-beam f in the form of a luminous segment s or part of a luminous segment s which makes up said global luminous beam Fx'.

[0062] A luminous segment s is in the form of a rectangle whose length is vertical with respect to the position of the luminous device 1 in the vehicle 2. Thus, each meta-lens 121 creates a luminous segment s, or a subgroup of meta-lenses 121 creates a luminous segment s. In other words, a segment s is formed from a single collimated sub-beam f or from a plurality of collimated sub-beams f. The collimated sub-beams f may be contiguous or not.

[0063] In a non-limiting embodiment, a metal lens 121 has a surface area less than or equal to 1 mm²2 If the surface area is larger, it requires excessive computing power to define the optimal distribution of the nano-pillars 121.2 of the metal lens 121. Thus, thanks to these small dimensions, a better manufacturing yield is achieved, resulting in a less expensive lighting device 1. Indeed, since the scrap rate depends on the surface area, smaller metal lenses 121 produce less waste.

[0064] Furthermore, in a non-limiting embodiment, the meta-lenses 121 have a size equal to the first step ps defined between two adjacent micro-lenses 111 of two different adjacent pairs p. This allows the surface of the corresponding light sub-beam f to be intercepted.

[0065] Due to the replacement of the bulky elements—light guides and projection optics—of the prior art with small-area mini light sources 100, small-area microlenses 111, and small metalenses 121, the depth of the three matrices 10, 11, and 12, and therefore of the lighting device 1, is very small. In a non-limiting embodiment, the distance L' (illustrated in Figure 1) between the output of matrix 10 and the output of matrix 12 is less than 4 mm. In a non-limiting variant, the distance L' is at least 3 mm. Depth is defined as the distance along a longitudinal axis AA' (illustrated in Figure 1) that passes through all three matrices 10, 11, and 12.

[0066] Each meta-lens 121 is configured to receive a collimated light sub-beam f and modify its propagation phase φ so that it is oriented in a given propagation direction P (illustrated in the figure). In the remainder of the description, the propagation phase φ is otherwise referred to as phase φ.

[0067] Each metal lens 121 has a light refractive index n2 (illustrated in Figure 1) for the nanopillars 121.2 (described later), or more simply, the refractive index n2. In a non-limiting embodiment, the light R used to illuminate a metal lens 121 covers a wavelength range λ from 400 to 780 nm, and the material used for each metal lens 121 (i.e., for the nanopillars 121.2) has different refractive index values ​​n2 depending on this wavelength λ. In a non-limiting embodiment, the light R can also cover a wavelength in the infrared or near-infrared.

[0068] Thus, in non-limiting examples: - n2 = 2.1 for λ = 631nm (red), - n2 = 2.47 for λ = 450nm (blue), - n2 = 2.38 for λ = 550nm (green), - n2 = 2.35 for λ = 621nm (red) and 632nm (super red).

[0069] In a non-limiting embodiment, all the meta-lenses 121 of the matrix 12 have the same refractive index n2, or different refractive indices n2.

[0070] In a first, non-limiting embodiment, all the light sources 100 emit light R over the same wavelength range λ. In a second, non-limiting embodiment, the light sources 100 each emit light R over different wavelength ranges λ. In a third, non-limiting embodiment, some light sources 100 emit light R over the same wavelength range λ, and other light sources 100 emit light R over different wavelength ranges λ.

[0071] Since the 100 light sources can be activated independently, using different wavelengths λ allows for the creation of an overall light beam Fx' of different colors depending on the activation, including in the infrared range by incorporating infrared light sources among the 100 light sources in a non-limiting example. This enables the implementation of a lidar-like detection function in addition to the standard photometric function.

[0072] Thus, the overall light beam Fx' in this case comprises two independent beams mixed together, the first beam being obtained by a first set of metal lenses 121 and the second beam being obtained by a second, different set of metal lenses 121. The first beam, for example, enables the detection of objects near the motor vehicle 2 and is an infrared beam, while the second beam, for example, enables the photometric function and is a visible beam. The two beams can have different propagation directions and different shapes.

[0073] As illustrated in the figure, a meta-lens 121 comprises: - a substrate 121.1, and - a plurality of nano-pillars 121.2.

[0074] The substrate 121.1 has a thickness E and a length L. In a non-limiting embodiment, the substrate 121.1 is made of glass.

[0075] The nano-pillars 121.2 are arranged on the substrate 121.1. They are defined by parameters including: - a radius r (illustrated in figures 3 and 4), - a height h (illustrated in figures 3 and 4), - a second step ps' between two nano-pillars 111.2. The second step ps' (illustrated in figures 3 and 4) represents the repetition frequency of the nano-pillars 121.2, - a material with a refractive index n2 (illustrated in the) which is the refractive index of the metal-lens 111, - a base bs (illustrated in the).

[0076] Note that the second step ps' is defined between the two longitudinal axes (illustrated with dashed lines in Figure 1) of two adjacent nano-pillars 111.2. In a non-limiting embodiment illustrated in Figure 1, the nano-pillars 111.2 have a disk-shaped base bs.

[0077] In a non-limiting embodiment, the nano-pillars 121.2 are made of Silicon Nitride (SiN). This material is easy to work with and produces less dust compared to other materials that can be used for the nano-pillars 111.2, such as, in non-limiting examples, Titanium Dioxide (TiO2) or Hafnium Oxide (HfO2).

[0078] In a non-limiting embodiment example, on a substrate 121.1 of thickness E=5 millimeters, a 70 nanometer layer of siN can be deposited and the siN layer etched to obtain the nano-pillars 121.2.

[0079] The nano-pillars 121.2 of each meta-lens 121 modify the propagation phase φ of a collimated sub-beam f passing through them. In other words, they add a phase delay. The result is that the collimated sub-beam f is deflected, giving it a desired propagation direction P, thus obtaining a desired light segment s or part of a desired light segment s. The set of segments s obtained forms the overall light beam Fx'. Examples of segments s from different embodiments of an overall light beam Fx' are illustrated in Figures 8 to 10.

[0080] To adjust the propagation direction P, the phase shift within a collimated light subbeam f is spatially controlled, which amounts to controlling the phase change gradient φ of the collimated light subbeams f. This is done using nano-pillars 121.2.

[0081] To this end, in a non-limiting embodiment illustrated in Figure 1, the 121.2 nanopillars have different radii r and the same height h. For the sake of clarity, only one height ha and one radius ra are referenced. It should be noted that the smaller the radius r, the less material a 121.2 nanopillar contains, which results in a minimal change in the phase φ, leading to a small phase delay. Conversely, when the radius r is larger, the more material a 121.2 nanopillar contains, resulting in a more significant change in the phase φ, leading to a larger phase delay.

[0082] As illustrated in Figure 1, the 111.2 nano-pillars have a radius r that increases from left to right. Each 121.2 nano-pillar will induce a different phase delay φ compared to its neighbor. The larger the radius r, the greater the phase delay φ. The radius r thus affects the phase φ of the collimated light sub-beam f. Since the r radii are smaller on the left, the phase delays on the left are smaller, and the light will be less delayed on the left than on the right. Note that the greater the delay, the more the wavefront is distorted and the more the resulting light beam Fx' is deflected.

[0083] As a reminder, light propagates perpendicularly to the wavefront. Typically, there is zero phase delay along the same line of the wavefront. As can be seen in the figure, the incoming wavefront Fo at the entrance of the meta-lens 121 (also called the incident wavefront Fo) is plane and perpendicular to the substrate 121.1 of the meta-lens 121.

[0084] Each nano-pillar 121.2 introduces a phase delay φ different from its neighbor, because they all have a different diameter, this differential phase delay then causes a deformation of the wavefront.

[0085] As can be seen on the diagram, the emerging wave front Fo' is distorted, which therefore causes a deviation of the emerging beam Fx'.

[0086] Thus, upon exiting a metal lens 111, the light, which always propagates perpendicularly to the wavefront (here, the emerging wavefront Fo', which is inclined), will be oriented along a given propagation direction P. Consequently, the light is oriented along a propagation direction P that has changed due to the phase shift of the light.

[0087] Note that the emerging wavefront Fo' has been delayed progressively and linearly. Each nano-pillar 121.2 is configured to induce a linearly evolving phase shift φ of the light, i.e., a linear phase shift. This results in a planar emerging wavefront Fo'. A phase shift between 0 and 2π is equivalent. Therefore, it is not necessary to create a linear phase shift along the entire length of the input wavefront Fo to obtain a continuous deflection. A phase shift between 0 and 2π can be performed as many times as needed. Thus, a linear phase shift between 0 and 10π is equivalent to five linear phase shifts between 0 and 2π.

[0088] Note that the phase φ is modulated between 0 and 2π. Note that with a phase φ = 0, there is no delay. With φ = π, there is a delay of λ / 2. From the perspective of the 121 meta-lens, as soon as φ = 2π, we return to a radius r of a 121.2 nano-pillar corresponding to 0, and therefore to the same 121.2 nano-pillar to avoid excessively large differences between the radii r. Thus, the 121 meta-lens comprises several sets of 121.2 nano-pillars defined in such a way as to obtain a phase shift of the light with a phase modulated between 0 and 2π.

[0089] The height h of the 121.2 nano-pillars allows control of the phase φ between 0 and 2π for a given wavelength λ. With the correct height h defined, all phase changes between 0 and 2π can be performed.

[0090] As explained previously, the radius r allows control of the phase φ of the light beam Fx.

[0091] The other parameters, namely the height h, the second step ps', and the material of the 121.2 nano-pillars, are defined to maximize the light transmission rate through the 121.2 nano-pillars. Maximizing the transmission rate means minimizing the absorption of light by the material of the 121.2 nano-pillar. Thus, these other parameters are determined to obtain minimum absorption over the range where the radius r is varied to obtain a phase shift (also called phase difference) between 0 and 2π.

[0092] By calculation, for a 111.2 nanopillar, a given height h and a given pitch ps are fixed, and its material is Silicon Nitride (SiN) with a refractive index n2 = 2.04. In the illustrated example (non-limiting), h = 1.35 μm and ps = 0.450 μm. Working with a constant height h facilitates the fabrication of 111.2 nanopillars. With a constant height h, the design of the 111.2 nanopillars must be adapted to achieve a phase shift between 0 and 2π while simultaneously maximizing light transmission to retain as much light as possible.

[0093] For a fixed height h and a fixed step size ps, we establish the light transmission curves as a function of the radius r, and the phase shift curves as a function of the radius r. Curves 6 and 7 illustrate the phase shift and light transmission for the best compromise for the chosen constant height h and for a given wavelength λ. Note that this compromise changes if the wavelength λ changes.

[0094] On the, in a non-limiting example, for a height h=1.35µm (micrometers), we can thus observe the phase variation φ in radians (on the ordinates) between 0 and 9 as a function of the radius r (on the abscissas) of the nano-pillars 111.2 which varies between 0.04 and 0.15 μm, for a given wavelength λ, here for λ=590nm in the illustrated non-limiting example.

[0095] In a non-limiting example, for a height h = 1.35 µm, we can observe a variation in light transmission Tx (on the y-axis) between 0 and 1 as a function of the radius r (on the x-axis) of the 111.2 nanopillars, which varies between 0.04 and 0.15 μm, for the given wavelength λ, here 590 nm. At a value of 0, no light passes through. At a value of 1, all light passes through.

[0096] Using these two curves, we can determine the height h and radius r of the 111.2 nanopillars that provide dynamic phase shift control while maximizing light transmission through the 111.2 nanopillars, all while maintaining manufacturability. We can thus find the values ​​of all the parameters of a 111.2 nanopillar to obtain the possible phase shift (or phase difference) and transmission values, and in particular a transmission rate close to 1 for a given wavelength λ. Note that if the results are not satisfactory, the procedure can be repeated by setting a different value for the height h.

[0097] Thus, the light device 1 is used in a projector 3 for vehicle 2.

[0098] As illustrated on the figure, the projector 3 comprises: - the light device 1 as described, - a control device 30 of the first matrix 10 of light sources 100.

[0099] The control device 30 is configured to activate different light sources 100 of the first matrix 10 so that the lighting device 1 performs, in particular, the photometric functions of rotating string LB, rotating road BH, and / or glare-free road ADB. The control device 30 is specifically configured to: - independently activate the different light sources 100, and - independently control the intensity I of the current i flowing through each light source 100. Thus, it independently controls the luminous flux of the light sources 100. Consequently, each segment s of the overall light beam Fx' has its own luminous power that is equal to or different from the luminous powers of the other segments s.

[0100] Figures 8, 9 and 10 illustrate a front view of the overall light beam Fx' exiting the projector 3. As illustrated in these figures, an overall light beam Fx' comprises a plurality of light segments s. It should be noted that a light segment s is obtained by means of one or more sets of light sources 100, micro-lens 111, meta-lens 121.

[0101] In particular, the overall light beam Fx' is composed of: - first segments s1 located above a horizontal cut ch, - second segments s2 located below the horizontal cut ch, - third segments s3 located at the level of the horizontal cut ch.

[0102] In the following description, the first segments s1 are also otherwise referred to as segments s1, the second segments s2 are also otherwise referred to as segments s2, and the third segments s3 are also otherwise referred to as segments s3.

[0103] The first s1 segments are intended for the photometric road function.

[0104] As illustrated in the figure, for the LB_B rolling code photometric function, the first segments s1 are off, meaning the corresponding light sources 100 are deactivated, and the second segments s2 and third segments s3 are on, meaning their respective light sources 100 are activated. In the figure, when segments s are off, they are white. When they are on, they are gray. The gray color varies depending on the light intensity, also known as power. The darker the gray, the greater the power.

[0105] The second segments s2 and the third segments s3 are illuminated with different intensities at specific locations. The difference in intensities varies from very low to very high. The intensity decreases towards the outer edge of the overall light beam Fx'. This decrease is visualized on the map with the gray color becoming lighter towards the outside, while a darker gray color indicates a higher intensity.

[0106] To simulate the movement of the rotating photometric function LB_B, the hot spot of the overall light beam Fx', i.e., its maximum intensity, is moved by activating and deactivating the light sources 100 corresponding to the segments s that must be illuminated or extinguished, while simultaneously adjusting the current intensity I of these activated light sources 100. Thus, in a non-limiting example, if vehicle 2 turns right, the right-hand segments s2 and s3, i.e., those located on the right of the beam, are illuminated with a high light intensity, while the left-hand segments s2 and s3, i.e., those located on the left of the beam, are illuminated with a lower light intensity.Thus, the control device 30 deactivates the light sources 100 corresponding to the first segments s1 to turn them off and activates the light sources 100 corresponding to the second segments s2 and third segments s3 to turn them on, and adjusts their intensity I to a current i to adjust their corresponding luminous flux. In this way, motion is simulated by changing the light intensity.

[0107] As illustrated on the, for the rotating road photometric function HB_B, the first segments s1, the second segments s2 and the third segments s3 are lit, i.e. the corresponding respective light sources 100 are activated.

[0108] The first segments s1 are illuminated to perform the photometric route function. The first segments s1, the second segments s2, and the third segments s3 are illuminated with different intensities at specific locations.

[0109] The difference in power varies from very small to very large. The power decreases towards the outside of the overall light beam Fx'. This decrease is visualized on the graph with the gray color becoming lighter towards the outside, while a darker gray color indicates a higher power.

[0110] To simulate the movement of the rotating road photometric function HB_B, the hot spot of the overall light beam Fx', i.e., its maximum intensity, is moved by activating and deactivating the 100 light sources corresponding to the segments s that must be illuminated or extinguished, while also varying the current intensity of these 100 activated light sources. Thus, in a non-limiting example, if vehicle 2 turns right, the right-hand segments s1, s2, and s3, i.e., those located on the right of the axis, are illuminated with a high light intensity, while the left-hand segments s1, s2, and s3, i.e., those located on the left of the axis, are illuminated with a lower light intensity. Thus, the control device 30 activates the light sources 100 corresponding to segments s1, s2 and s3 to turn them on and adjusts their intensity I in current i to adjust their corresponding luminous flux.Thus, motion simulation is performed by changing the intensity of light.

[0111] Thus, when projector 3 performs the photometric functions of rolling low beam (LB_B) and rolling high beam (HB_B), it performs the photometric function known as a rotating headlight, or DBL for "Dynamic Bending Light." By varying the luminous intensity in the different dedicated segments, this DBL photometric function is simulated by changing the angular position of the maximum intensity of the overall light beam (Fx'). This creates an impression of movement.

[0112] As illustrated on the, for the ADB glare-free road photometric function, only part of the first segments s1 are lit, i.e. the corresponding respective light sources 100 are activated, and the second segments s2 and the third segments s3 are lit, i.e. the corresponding respective light sources 100 are activated.

[0113] When a sensor (not shown) on vehicle 2, such as a camera, detects another vehicle approaching from the opposite direction or another vehicle being followed by vehicle 2 at a given location, the first segments s1 that could dazzle the area where the oncoming or followed vehicle is located are switched off to avoid dazzling the oncoming vehicle. As illustrated in the figure, the first switched-off segments s1 are white and are located at the center of the overall light beam Fx' in the non-limiting example shown. These are segments s that extend beyond the horizontal cutoff ch. Thus, the control device 30 deactivates the light sources 100 corresponding to the first "dazzling" segments s1 to switch them off. The third segments s3 (shown in white) located at the center of the overall light beam Fx' are also switched off to simulate the cutoff of the code.When the oncoming vehicle is very far from the motor vehicle 2 equipped with the lighting device 1, the driver of that oncoming vehicle may be dazzled by segments s3 of the code. Therefore, the corresponding segments s3 are switched off.

[0114] The other first segments s1 (not white in the image), the second segments s2, and the third segments s3 are illuminated with different intensities at specific locations to simulate the optimal distribution of a traditional lighting beam (intense in the middle and less so at the edges). Thus, the control device 30 activates the light sources 100 corresponding to these segments s1, and to segments s2 and s3, to illuminate them and adjusts their intensity I to a current i to adjust their corresponding luminous flux.

[0115] Of course, the projector is also configured to perform: - a classic photometric road function, referenced HB_C on the and called "High Beam" in English; - a photometric ground projection function, referenced RW on the , called "road writing" in English. This photometric function allows images, such as symbols, to be projected onto the ground. A portion of the 12-metal lens array can thus be dedicated to creating ground symbols.

[0116] In the case of the classic HB_C road photometric function, the first segments s1 are illuminated, meaning their respective light sources 100 are activated, and the second segments s2 and third segments s3 are also illuminated, meaning their respective light sources 100 are activated. Thus, the control device 30 activates the light sources 100 corresponding to segments s1, s2, and s3 and adjusts their intensity I into a current i to produce different luminous fluxes, mimicking the distribution in a traditional lighting beam (intense in the middle and less so at the edges).

[0117] Of course, the description of the invention is not limited to the embodiments and the scope described above. Thus, in other, non-limiting embodiments, the base bs of the nano-pillars 111.2 is oblong or elliptical in shape. Thus, in another, non-limiting embodiment, the nano-pillars 111.2 have the same radius r but different heights h.

[0118] Thus, the described invention has the following advantages in particular: - it allows the simulation of movement of a projector 3 of the vehicle 2 without the vehicle itself being set in motion; the projector 3 remains static, - it allows for a compact lighting device 1, particularly in terms of depth, - by eliminating the use of light guides in the form of rods, it eliminates an injection molding process for producing light guides that must withstand heat, - it does not require very large light sources to produce the different segments s of the overall light beam Fx', unlike the prior art, - it does not require very powerful light sources 100, less than approximately 100 lumens, unlike the prior art which requires light sources of approximately 400 lumens, - due to the small size of the light sources used as well as their lower power,It is possible to have more light sources than in the prior art: thus, it allows the sub-beams f to be superimposed as many times as desired to increase the luminous power of a single segment s; it allows for a very compact lighting device 1 compared to the prior art, the corresponding distance L' of which is approximately 2 to 3 cm; this distance L' is thus reduced by a factor of approximately 10; it allows for a lighting device 1 that is easily integrated into a vehicle: the lighting device 1 can be positioned in unusual locations within the vehicle 2 due to the use of the third matrix 12, which allows the collimated light sub-beams f to be oriented; it allows for a lighter lighting device than in the prior art; indeed, in this prior art, the light guides and the projection optics are thicker.longer and heavier than the set of three matrices 11, 12 and 13.

Claims

Light device (1) for vehicle (2) comprising: - a first array (10) of light sources (100) configured to emit light (R) forming an incoming light beam (Fx); characterized in that the light sources (100) are mini-light sources (100), and in that said light device (1) further comprises: - a second array (11) of micro-lenses (111) comprising a plurality of pairs (p) of micro-lenses (111), each pair (p) being arranged opposite a light source (100) and configured to collimate said light (R) so as to create a collimated sub-beam (f);- a third array (12) of meta-lenses (121) configured to form an overall light beam (Fx') and comprising a plurality of meta-lenses (121), each meta-lens (121) being arranged opposite each pair (p) of micro-lenses (111) and being configured to orient the collimated sub-beam (f) of said pair (p) and to form it in the form of a light segment (s) or a part of a light segment (s) composing said overall light beam (Fx').; Light device (1) according to claim 1, characterized in that the light sources (100) comprise an emitter with a size between 100 and 200 micrometers on each side. Light device (1) according to any one of the preceding claims, characterized in that a micro-lens (111) has a side between 0.5 and 2 millimeters. A lighting device (1) according to any one of the preceding claims, characterized in that said metal lenses (121) have a surface area less than or equal to 1 mm² 2 . Light device (1) according to any one of the preceding claims, characterized in that the light sources (100) have a size less than or equal to a first step (ps) defined between two adjacent micro-lenses (111). Light device (1) according to any one of the preceding claims, characterized in that the meta-lenses (121) have a size less than or equal to a first step (ps) defined between two adjacent micro-lenses (111). Light device (1) according to claim 5 or claim 6, characterized in that said first step (ps) is between 0.5 and 2 millimeters. Light device (1) according to any one of the preceding claims, characterized in that the meta-lenses (121) of the third matrix (12) comprise nano-pillars (121.2) defined by a radius (r), a height (h) and a second pitch (ps') between two nano-pillars (121.2). Light device (1) according to the preceding claim, characterized in that said nano-pillars (111.2) are made of Silicon Nitride (siN). Light device (1) according to claim 8 or claim 9, characterized in that said nano-pillars (111.2) have different radii (r) and the same height (h). Light device (1) according to any one of the preceding claims, characterized in that the light sources (100) are semiconductor light sources or laser sources. Light device (1) according to any one of the preceding claims, characterized in that the light sources (100) can be activated independently of each other. Light device (1) according to any one of the preceding claims, characterized in that each light source (100) is traversed by a current (i) whose intensity (I) is controllable independently of the other light sources (100). Projector (3) for vehicle (2), characterized in that said projector (3) comprises: - said light device (1) according to any one of the preceding claims; - a control device (30) for the first matrix (10) of light sources (100), said control device (30) being configured to activate different light sources (100) of said first matrix (10), and said light device (1) being configured to perform at least one of the following photometric functions: - a rotating code photometric function (LB_B), - a rotating road photometric function (HB_B), - a glare-free road photometric function (ADB).

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