FR3085738A1 - LIGHT MODULE - Google Patents

Abstract

The invention relates to a light module (1) comprising: - at least one light source (11) configured to emit light rays (R) to generate a light beam; - at least one optical element (10) configured to cooperate with said at least one light source (11) for deflecting said light rays (R); Characterized in that said at least one optical element (10) comprises at least one anti-reflective structure (100) comprising a periodic pattern (101) configured to obtain a refractive index gradient (G) evolving as a function of an index of refraction (ns) of said at least one optical element (10) and of a refractive index (n0) of another medium (13) so as to reduce the reflection of said light rays (R) on a diopter (14) separating said at least one optical element (10) and the other medium (13).

Description

LIGHT MODULE

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a light module.

It finds a particular but non-limiting application in front high beams for a motor vehicle.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

An optical module for a motor vehicle in a manner known to a person skilled in the art comprises:

- at least one light source configured to emit light rays to generate a light beam;

- At least one optical element configured to cooperate with the light rays of said light beam.

Said light module is part of a light device which is a front high beam of a motor vehicle, in which an adaptive lighting function, otherwise called AFS function, is implemented, known by the acronym "ADAPTIVE" FRONT-LIGHTING SYSTEMS ”. Such an AFS function is intended to automatically detect a road user liable to be dazzled by the light beam and to modify the outline of said light beam so as to create a shadow zone, otherwise known as a tunnel, on the 'location of the detected user while continuing to illuminate the road on both sides of the user.

The light beam is a segmented beam. For this purpose, as illustrated in FIG. 1a, one or more light sources 11 _Ί are deactivated so as to extinguish one or more segments Si of the light beam F illustrated in FIG. 1b, to avoid the road user who is generally a driver of a motor vehicle who comes in front of the motor vehicle concerned, or a driver of a motor vehicle in front of said motor vehicle concerned, to be dazzled. The extinct segments δ _Ί form a tunnel.

A drawback of this prior art is that stray light, coming from the other segments still on S ₂ of the light beam F, is added in the tunnels where the segment or segments Si are extinguished. Indeed, as illustrated in FIG. 1a, light rays R coming from the light sources 11 _{2 which} are lit are reflected by the Fresnel reflections on the faces 10a, 10b of the optical element referenced 10. This results in multi-reflections . The reflected rays are referenced Rr in FIG. 1a. Consequently, in the event of too high an intensity, this stray light dazzles the driver of the motor vehicle who crosses or who is in front of the motor vehicle concerned. Furthermore, the intensity level of this stray light does not comply with the UNECE-R123 regulations issued by the United Nations Economic Commission for Europe which defines the level of light not to be exceeded in so-called ADB (Adaptive Driving) lines Beam) (see Annex 3 Table 7). For example, in the case of line 1 corresponding to the case of a vehicle crossed at 50 meters, the level of stray light must not exceed 625 candelas (cd). In this context, the present invention aims to propose a light device for a motor vehicle which makes it possible to solve the mentioned drawback.

GENERAL DESCRIPTION OF THE INVENTION

To this end, the invention proposes a light module comprising:

- at least one light source configured to emit light rays to generate a light beam;

- at least one optical element configured to cooperate with said at least one light source for deflecting said light rays;

characterized in that said at least one optical element comprises at least one anti-reflective structure comprising a periodic pattern configured to obtain a gradient of refractive index evolving as a function of a refractive index of said at least one optical element and of an index refraction of another medium so as to reduce the reflection of said light rays on a diopter separating said at least one optical element and the other medium.

According to non-limiting embodiments, said light module can also include one or more additional characteristics taken alone or according to all technically possible combinations, among the following:

According to a nonlimiting embodiment, said gradient of refractive index gradually evolves as a function of said refractive index of said at least one optical element and said refractive index of another medium.

According to a nonlimiting embodiment, said periodic pattern comprises a sinusoidal profile.

According to a nonlimiting embodiment, said periodic pattern comprises a parabolic profile, a triangular profile.

According to a nonlimiting embodiment, said optical element comprises an entry face and an exit face and said anti-reflection nanostructure is located on said entry face and / or on said exit face.

According to a nonlimiting embodiment, said periodic pattern is repeated at a step less than the wavelengths in the visible range.

According to a nonlimiting embodiment, said pitch is between 100nm and 300nm.

According to a nonlimiting embodiment, said periodic pattern comprises an amplitude between 150nm and 750nm.

According to a nonlimiting embodiment, said optical element is a primary optical element comprising a plurality of light guides, an optical correction element, or a projection optic.

According to a nonlimiting embodiment, said optical element is composed of glass, polycarbonate or poly (methyl methacrylate).

According to a nonlimiting embodiment, the other medium is air.

According to a non-limiting embodiment, said gradient of refractive index gradually evolves from the refractive index of the other medium towards the refractive index of said optical element or vice versa.

According to a nonlimiting embodiment, one or more light sources are configured to be deactivated so as to extinguish one or more segments of said segmented light beam.

According to a nonlimiting embodiment, said structure is a nanostructure.

According to a nonlimiting embodiment, said structure is a sub-wavelength structure.

According to a nonlimiting embodiment, the light module is a motor vehicle light module.

According to a nonlimiting embodiment, the anti-reflection structure comprises a film on which said periodic pattern is inscribed, said film being in contact with said optical element.

According to a nonlimiting embodiment, said periodic pattern is written directly on said optical element.

A light device for a motor vehicle is also proposed, comprising a light module according to any one of the preceding characteristics.

According to a nonlimiting embodiment, said light device is a headlight adapted to generate a high beam.

An optical element of a light module of a motor vehicle is also proposed, said optical element being configured to cooperate with the light rays of a light beam generated by at least one light source of said light module, characterized in that said optical element comprises an antireflection structure comprising a periodic pattern configured to obtain a refractive index gradient which evolves as a function of a refractive index of said optical element and of a refractive index of another medium which reduces the reflection of said light rays on a diopter separating said optical element and the other medium.

A motor vehicle is also proposed comprising a light module according to any one of the preceding characteristics, or a light device according to any one of the preceding characteristics.

BRIEF DESCRIPTION OF THE FIGURES

The invention and its various applications will be better understood on reading the description which follows and on examining the figures which accompany it:

- Figure 1a shows a light module of the prior art cooperating with light rays of a light beam generated by a plurality of light sources of the light module, a plurality of light sources being deactivated so as to turn off one or several segments of the light beam;

- Figure 1b shows the light beam of which one or more segments are extinguished by deactivation of the plurality of light sources of Figure 1a;

- Figure 2 shows a schematic view of a light device of a motor vehicle comprising a light module with a plurality of light sources and several optical elements, at least one optical element of which comprises an antireflection structure with a periodic pattern, according to a non-limiting embodiment of the invention;

- Figure 3a schematically shows a plurality of light sources and one of the optical elements of Figure 2, several light sources being extinguished to extinguish segments in the light beam generated by the light sources, according to a non-limiting embodiment;

- Figure 3b shows the light beam of which one or more segments are extinguished by deactivation of the light sources of Figure 3a;

- Figure 4 shows different profiles of the periodic pattern composing the anti-reflective structure of the optical element of Figures 2 and 3a, according to a non-limiting embodiment; and

- Figure 5 shows a gradual evolution of a refractive index gradient obtained by an anti-reflection structure of the optical element of Figures 2 and 3a, according to a non-limiting embodiment.

DESCRIPTION OF MODES FOR CARRYING OUT THE INVENTION

Identical elements, by structure or by function, appear in the different figures keep, unless otherwise specified, the same references.

The light module 1 according to the invention is described with reference to Figures 2 to 5.

In a nonlimiting embodiment, it is a light module 1 of a motor vehicle 3.

By motor vehicle is meant any type of motor vehicle. Thus, the motor vehicle 3 comprises the light module 1.

The light module 1 includes:

- At least one light source 11 configured to emit light rays R to generate a light beam F;

- At least one optical element 10 configured to cooperate with said at least one light source 11 for deflecting said light rays R.

In a nonlimiting embodiment, the light module 1 comprises a plurality of light sources 11. This nonlimiting embodiment is taken as a nonlimiting example in the following description.

The light module 1 has a longitudinal optical axis A.

In a nonlimiting embodiment, the light module 1 comprises a plurality of optical elements 10.

As illustrated in FIG. 2, in a nonlimiting embodiment, the light module 1 is part of a light device 2 of the motor vehicle 3. Thus, the motor vehicle 3 comprises the light device 2. In one mode of non-limiting embodiment, the light device 2 is a headlight adapted to generate a high beam. It comprises a box (not shown) in which the light module 1 is arranged with said optical element 10 and a lens (not shown) for closing the box.

• Light sources 11

As illustrated in FIG. 3a, the plurality of light sources 11 form a matrix 12 of light sources. The optical axis A passes substantially in the middle of the matrix 12. The matrix 12 extends in a plane orthogonal to the optical axis A.

The light sources 11 are arranged on a support 120 (illustrated in FIG. 2). In a nonlimiting embodiment, this support 120 is a printed circuit board, known by the acronym PCB "Printed Circuit Board".

In a nonlimiting embodiment, the light sources 11 are semiconductor light sources. In a nonlimiting alternative embodiment, said semiconductor light sources 11 are part of a light emitting diode. By light emitting diode is meant any type of light emitting diode, whether in non-limiting examples of LEDs ("Light Emitting Diode >>), OLEDs (" organic LEDs >>), AMOLEDs (Active-Matrix-Organic LEDs) ), FOLED (Flexible OLED), a monolithic LED matrix or even a microLED matrix.

The light sources 11 are configured to emit light rays R to generate a light beam F. The light beam F is matrix or pixelated.

In a nonlimiting embodiment, the light beam F is a segmented light beam.

The matrix light beam F is an adaptive light beam F, known by the acronym "Adaptive Driving Beam".

One or more segments S can be extinguished so as to form one or more tunnels in the light beam F, tunnel referenced Si in FIG. 3b.

For this purpose, one or more light sources 11 of the light module 1 are configured to be deactivated so as to extinguish one or more segments S of the light beam F.

Thus, in the nonlimiting example illustrated in FIG. 3a, three light sources are extinguished. They are referenced 11 _Ί . They make it possible to extinguish segments referenced Si in FIG. 3b. The light sources that are on are referenced 11 ₂ and the segments that remain on are referenced S ₂ in FIG. 3b.

It will be noted that in a manner known to a person skilled in the art, the light device 2 comprises an electronic control unit (not shown) configured to control the deactivation and activation of the matrix 12 of light sources 11.

• Optical element 10

The optical element 10 is arranged longitudinally in front of the matrix 12 of the light sources 11.

In a nonlimiting embodiment, the optical element 10 is composed of glass, of thermoformable plastic dedicated to optics such as for example polycarbonate, known under the abbreviation PC, or of poly (methyl methacrylate) known under the abbreviation PMMA.

In a nonlimiting example illustrated in FIG. 2, there are three optical elements in the light module 1.

Thus, as illustrated in FIG. 2, the light module 1 comprises:

- a primary optical element 10 _Ί comprising a plurality of light guides 1010;

an optical element for correcting the curvature of fields 10 ₂ , otherwise called an optical correcting element 10 ₂ in the following description;

- projection optics 10 ₃ .

The light sources 11 emit light rays R in a very open cone of light. In addition, each light source 11 has an emission surface whose dimensions must be adapted to be able to be used effectively by the light module 1. For this purpose, a light guide 1010 is arranged opposite each light source 11 to modify the distribution of the light rays R emitted by the light source 11.11 guides the light rays R from the light source 11 towards the optical correction element 10 ₂ . The primary optical elements comprising a plurality of light guides being known to those _skilled in the art, the primary optical element 10 _Ί is not described in detail here.

The optical correction element 10 ₂ is configured to correct in particular the aberration of field curvature of the optical projection element 10 ₃ . It will be noted that the aberration of field curvature is an optical aberration which arises from the fact that the image of a large planar object is formed on a paraboidal surface and not on a plane. Thus, the image of a plane is not a plane but a concave spherical surface in the context of a converging lens. Correcting this optical aberration amounts to making the image of a plane a plane. To this end, in a nonlimiting embodiment, the optical correction element 10 ₂ may for example include a Petzval surface.

In a nonlimiting embodiment, the light module 1 comprises one or more optical correction elements 10 ₂ . Since the optical correction elements are known to a person skilled in the art, the optical correction element 10 ₂ is not described in detail here.

The projection optics 10 ₃ is configured to project light emitted by the light sources 11. This projection optics 10 ₃ creates a real, and possibly anamorphic image, of a part of the light module 1, for example the light source 11 itself or a mask, or of an intermediate image of the light source 11, at a distance (finite or infinite) very large compared to the dimensions of the light module 1 (with a ratio of the order of at least 30 , preferably 100) of the light module 1. This projection optics 10 ₃ may comprise one or more reflectors, or one or more lenses, or one or more light guides or in a combination of these possibilities.

At least one optical element 10 of the light module 1 comprises at least one anti-reflection structure 100 comprising a periodic pattern 101. In a first non-limiting example, the correction element 10 ₂ comprises at least one anti-reflection structure 100. In a second example not limiting, the optical projection element 10 ₃ comprises at least one anti-reflection structure 100.

In a nonlimiting embodiment, several optical elements 10 comprise at least one antireflection structure 100 comprising a periodic pattern 101. In a third nonlimiting example, the correction element 10 ₂ and the optical projection element 10 ₃ each comprise at least one anti-reflection structure 100.

In nonlimiting embodiments, the periodic pattern 101 comprises, as illustrated in FIG. 4:

a) a triangular profile; or

b) c) a parabolic profile; or

d) a sinusoidal profile;

The triangular profile makes it possible to have either a periodic pattern 101 in the form of a pyramid with a square base or with a triangular base, or a periodic pattern 101 of conical shape.

The parabolic profile makes it possible to have a paraboloid or semi-spherical 101 periodic pattern.

In a nonlimiting embodiment, said periodic pattern 101 is repeated at a pitch p1 less than the wavelengths in the visible range. The light thus does not perceive the anti-reflective structure 100. It is thus a nanostructure. It is also called sub-wavelength structure 100. This anti-reflection structure 100 can be seen as a sub-wavelength network. Diffraction theory states that when the period of a grating is sufficiently less than the wavelength of the incident light, the non-zero order reflected diffraction is evanescent over a wide range of wavelengths and incident angles.

It is recalled that the wavelengths in the visible range are between -380 and -780 nanometers (nm). In a non-limiting variant, the step p1 is between 100nm and 300nm.

In a nonlimiting embodiment, said periodic pattern 101 comprises an amplitude P between 150nm and 750nm. Note that below 150nm, the periodic pattern 101 is difficult to achieve.

The periodic pattern 101 is therefore a nano-pattern which makes it possible to have the antireflection structure 100.

It will be noted that the distance d at the base between two periodic patterns 101 is more or less great depending on the manufacturing possibilities. This distance d can be equal to 0.

As illustrated in FIG. 3a, the optical element 10 comprises an inlet face 10a and an outlet face 10b and the anti-reflection structure 100 is located on said inlet face 10a and / or said outlet face 10b. Thus, the diopter 14i is the entry face 10a and the diopter 14 ₂ is the exit face 10b.

In a non-limiting embodiment, the anti-reflective structure 100 of the diopter 14 extends over all or part of a diopter 14. In a non-limiting alternative embodiment, the anti-reflective structure 100 extends over the diopter 14 to the place where the light rays R enter the optical element 10.

The anti-reflection structure 100 comprises the periodic pattern 101 which is configured to obtain a gradient of refractive index G which evolves gradually as a function of a refractive index ns of said optical element 10 and of a refractive index nO of another medium 13 so as to reduce the reflection of said light rays R on a diopter 14 separating said optical element 10 and the other medium 13. This other medium 13 is a medium different from the optical element 10. This other medium 13 is otherwise called outdoor environment.

It will be noted that it is the shape of the periodic pattern 101 which plays on the gradient of refractive index G.

As illustrated in FIG. 3a, the other medium 13 is air A. In the nonlimiting example illustrated, there are two diopters 14. A first diopter 14 _Ί which separates air A from the surface of the face input 10a. A second diopter 14 ₂ which separates the air A from the outlet surface 10b of the optical element 10. In the nonlimiting example illustrated, the first diopter 14 _Ί comprises the anti-reflection structure 100.

The optical element 10 includes a refractive index ns. In nonlimiting examples, the refractive index ns, around 550 nm,:

- glass is equal to 1.52;

- of the PC is equal to 1.59;

- the PMMA is equal to 1.49.

Air A has a refractive index nO approximately equal to 1.

The incident light L1 is formed by the light rays R of the light beam F which arrives on the diopter 14 _Ί in the nonlimiting example illustrated. When the incident light Ll arrives at the surface separating the air A from the optical element 10, namely the first diopter 14 _Ί comprising the anti-reflection structure 100, the incident light Ll is no longer reflected because the Fresnel reflections are reduced see annihilated. Indeed, thanks to the anti-reflective structure 100, the refractive index gradually evolves from the refractive index nO of the air A to the refractive index ns of the optical element 10 in the nonlimiting example taken. Thus, the incident light L1 will not undergo a sudden variation in the refractive index, which would cause proportional reflections. There is thus a gradual change in the refractive index which creates a gradient of refractive index G which reduces the reflection of the incident light L1 on the surface of the diopter 14 _Ί .

There is no longer a clear air-optical interface 10, and therefore there is no sudden change in refractive index. Instead, there is a change in the refractive index n which changes continuously as the light travels through the subwavelength structure 100 and this allows for a smoother and smaller change in the index of global refraction. As a result, more light is transmitted and much less light is reflected thanks to the sub-wavelength structure 100.

If we look at the incident light L1 which propagates from the other medium 13 (here the air A) towards the optical element 10, we have a gradient of refractive index G which gradually changes from the refractive index nO from the other medium 13 towards the refractive index ns of said optical element 10. In the nonlimiting example of air A, it is therefore increasing here.

Conversely, if we look at the incident light L1 which propagates from the optical element 10 to the other medium 13 (here air A), we have a gradient of refractive index G which gradually changes from the index of refraction ns of said optical element 10 towards the refractive index nO of the other medium 13 as illustrated on the curve of FIG. 5 where the depth P is on the abscissa and the refractive index n is on the ordinate. In the nonlimiting example of air A, it is therefore decreasing here.

An anti-reflection structure 100 with a periodic pattern 101 formed of pyramids is illustrated in FIG. 5. To understand the functioning of the structure, one could cut this anti-reflection structure 100 slice by slice, this would be equivalent to creating layers c of refractive index equivalent n _eq (X) = X * ns + (1 - X) * nO, with X the relative thickness which is equal to the height of a layer c divided by the height of the periodic pattern 101. Note that the thickness X is between 0 and 1. This understanding of the phenomenon is known by the English name: "Effective Medium Theory" (EMT).

In the nonlimiting example illustrated, there are five layers c1 to c5 illustrated to explain the equivalent refractive index n _eq (X).

Before layer c1, we have neq = nO. When the incident light L1 arrives on the top of the pyramids, we are on the layer c1. n _eq (X) = 20% ns + 80% nO in a nonlimiting example. For the layer c2, n _eq (X) = 40% ns + 60% nO in a nonlimiting example. For layer c3, n _eq (X) = 60% ns + 40% nO in a nonlimiting example.

For layer c4, n _eq (X) = 80% ns + 20% nO in a nonlimiting example. Until arriving at layer c5 where n _eq (X) = ns.

The structure 100 thus makes it possible to obtain a plurality of layers c1 to c5 equivalent of refractive indices, called equivalent, n _eq which are different from each other and which make it possible to reduce the reflection of the incident light L1.

The more the incident light L1 is in contact with the surface of the pyramids 101 of the structure 100 the more the equivalent refractive index n _eq will tend towards the refractive index ns, and this in a progressive manner. This gives a gradient of refraction index G which gradually evolves from the refractive index nO of air A to the refractive index ns of the optical element 10 of the layers c1 to c5. The incident light L1 passes through the optical element 10 with no reflection. There is thus the transmitted light LT substantially equivalent to the incident light L1. There is a decrease in light loss by reflection, and more light is transmitted.

In the nonlimiting example of the periodic pattern 101 in the form of a pyramid, the refractive index gradient G as a function of the refractive index ns and the refractive index nO is equal to the derivative of n _eq (X) , equivalent refractive index as a function of the relative thickness X of the antireflection structure 100, with: n _eq (X) = X * ns + (1 - X) * nO.

In the first exemplary embodiment illustrated in FIG. 3a, with the optical correction element 10 ₂ , there will be only a tiny residue of light reflected according to Fresnel reflections on the surface of the diopter 14 _Ί . Thus very little reflected light returns to the primary optical element 10 _Ί which is located behind the optical correction element 10 ₂ , unlike the state of the prior art in FIG. 1a. There are thus very few reflections towards the interior of the light module 1. In this mode, the gradient of the refractive index G gradually changes from the refractive index nO of the air A towards the refractive index ns of said optical correction element 10 ₂ . It is growing.

In the second exemplary embodiment (not illustrated) with the optical projection element 10 ₃ , there will be only a tiny residue of light reflected according to Fresnel reflections on the surface of the diopter 14 (not illustrated) of the projection optical element 10 ₃ . Thus, very little reflected light returns to the optical correction element 10 ₂ which is located behind the optical projection element 10 ₃ , unlike the prior art in FIG. 1a. There are very few reflections into the interior of the light module

1. In this mode, the refractive index gradient G gradually evolves from the refractive index nO of air A to the refractive index ns of said projection optical element 10 ₃ . It is growing.

Thus, when the light sources 11 are deactivated to create a tunnel Si in the light beam F, there is very little stray light due to the Fresnel reflections which parasitize said tunnel δ _Ί . Thus, as illustrated in FIG. 3b, it can be seen that the tunnel Si is darker than the tunnel Si of the prior art illustrated in FIG. 1b.

This is all the more true if the optical correction element 10 ₂ and the optical projection element 10 ₃ each comprise at least one anti-reflection structure 100 according to the third nonlimiting exemplary embodiment (not illustrated).

Depending on the material of the periodic pattern 101, there are different manufacturing methods which are as follows.

For the periodic pattern 101 in glass, in nonlimiting embodiments the manufacturing methods used are:

- Photolithography with the inscription of periodic patterns 101 with a UV laser in a photosensitive resin known by the English name "holography litography with UV laser";

- lithographic printing by an electron beam known by the English name "direct writing electron-beam lithography".

For the periodic pattern 101 in PC or PMMA plastic material, in non-limiting embodiments the manufacturing methods used are:

- the nano-lithographic printing known as the Anglo-Saxon "nanoimprint lithography (NIL)";

- printing on a film under the Anglo-Saxon name "roll-to-plate", referenced R2P.

Thus, in a nonlimiting embodiment, said periodic pattern 101 is written directly on said optical element 10.

Thus, in a nonlimiting embodiment, the anti-reflection structure 100 comprises a film on which said periodic pattern is inscribed, said film being glued with said optical element.

Of course, the description of the invention is not limited to the embodiments described above.

Thus, in another nonlimiting embodiment, said light device 2 comprising the optical element 10 is an interior lighting device.

Thus, in another nonlimiting embodiment, said light device 2 comprising the optical element 10 is a rear light.

Thus, in a nonlimiting embodiment, the diopter 14 is the opposite inner face 10d to the outlet face 10b and / or the opposite inner face 10c to the inlet face 10a, and said anti-reflection structure 100 is located on said inner face 10c and / or said inner face 10d (illustrated in FIG. 3a).

Thus, the invention described has the following advantages in particular:

- it eliminates the Fresnel reflections on an optical element 10 (to a very small residual reflection) and thus makes it possible to increase the performance of the light module 1 as a whole;

- it eliminates multi-reflections;

- it eliminates stray light on the tunnels of the light beam F;

- it makes it possible to comply with UNECE-R123 regulations. Thus, for line 1 ADB defined in this regulation, the level of light intensity does not exceed 625 candelas so that a user of a motor vehicle who crosses the motor vehicle concerned at 50 meters or who is in front of said vehicle concerned is no longer dazzled;

- it is a more spectrally and angularly flexible solution compared to a so-called conventional anti-reflective coating solution produced by depositing several optical thin layers, otherwise called multilayer anti-reflective coating. Thus, because of the repeating pattern 101 of size smaller than the wavelength of the light, the spectral response of the sub-wavelength structure 100, is less sensitive to the angle of incidence and to the length d 'wave. In the case of the anti-reflective coating solution with several thin layers, the incident light which has an incident oblique angle does not then see the same thicknesses of the layers and the response of the anti-reflective coating is very dependent on the angle of incidence. This is for example observable in certain cases, such as on ophthalmic glasses, by green or magenta reflections;

- it is thus an anti-reflective solution not visible to the naked eye, unlike the multilayer anti-reflective coating solution which can have iridescence of different colors, such as blue-magenta;

- this solution can be more effective as a cycle unlike a multilayer anti-reflective coating solution which requires working under vacuum.

Claims (15)

1. Light module (1) comprising: - at least one light source (11) configured to emit light rays (R) to generate a light beam (F); - at least one optical element (10) configured to cooperate with said at least one light source (11) for deflecting said light rays (R); characterized in that said at least one optical element (10) comprises at least one anti-reflection structure (100) comprising a periodic pattern (101) configured to obtain a refractive index gradient (G) evolving as a function of an index of refraction (ns) of said at least one optical element (10) and of a refractive index (nO) of another medium (13) so as to reduce the reflection of said light rays (R) on a separating diopter (14) said at least one optical element (10) and the other medium (13). 2. Light module (1) according to claim 1, in which said refractive index gradient (G) evolves gradually as a function of said refractive index (ns) of said at least one optical element (10) and said refractive index ( nO) from another medium (13). 3. Light module (1) according to claim 1 or claim 2, wherein said periodic pattern (101) comprises a sinusoidal profile. 4. Light module (1) according to any one of the preceding claims, in which said optical element (10) comprises an inlet face (10a) and an outlet face (10b) and said anti-reflection nanostructure (100) is located on said inlet face (10a) and / or on said outlet face (10b). 5. Light module (1) according to any one of the preceding claims, in which said periodic pattern (101) is repeated at a pitch (p1) less than the wavelengths in the visible range. 6. Light module (1) according to the preceding claim, wherein wherein said pitch (p1) is between 100nm and 300nm. 7. Light module (1) according to any one of the preceding claims, wherein said periodic pattern (101) comprises an amplitude (P) between 150nm and 750nm. 8. Light module (1) according to any one of the preceding claims, in which said optical element (10) is a primary optical element comprising a plurality of light guides (1010), a correction field optical element, or a projection optics. 9. Light module (1) according to any one of the preceding claims, wherein said optical element (10) is composed of glass, polycarbonate or poly (methyl methacrylate). 10. Light module (1) according to any one of the preceding claims, in which the other medium (13) is air (A). 11. Light module (1) according to any one of the preceding claims, in which said refractive index gradient (G) gradually evolves from the refractive index (nO) of the other medium (13) towards the refractive index (ns) of said optical element (10) or vice versa. 12. Light module (1) according to any one of the preceding claims, in which one or more light sources (11) are configured to be deactivated so as to extinguish one or more segments (S) of said segmented light beam (F). 13. Light device (2) comprising a light module (1) according to any one of the preceding claims. 14. Light device (2) according to the preceding claim, wherein said light device (2) is a headlight configured to generate a high beam. 15. Optical element (10) of a light module (1) of a motor vehicle (3), said optical element (10) being configured to cooperate with the light rays (R) of a segmented light beam (F) generated by a plurality of light sources (11) of said light module (1), characterized in that said optical element (10) comprises an anti-reflection structure (100) comprising a periodic pattern (101) configured to obtain an index gradient of refraction (G) which evolves as a function of a refractive index (ns) of said optical element (12) and of a refractive index (nO) of another medium (13) so as to reduce the reflection of said light rays (R) on a diopter (14) separating said optical element (10) and the other medium (13).