Lighting module for a motor vehicle

Abstract

The present invention relates to a lighting module (2) comprising a primary lens (8), a secondary lens (10), and at least one light source (4) configured to generate light rays, the primary lens (8) comprising an entry surface (18) and an exit surface, the exit surface (20) of the primary lens (8) having a first curvature about a first axis (26) parallel to a first direction and a second curvature about a second axis (28) parallel to a second direction, the first axis (26) being perpendicular to the second axis (28), the primary lens (8) comprising a plurality of optical structures (38) arranged on a processing portion (30) of the exit surface (20) of the primary lens (8).

Description

Light module for motor vehicles.

[0001] The present invention relates to the field of lighting modules, and in particular to lighting modules intended for use in motor vehicles. More specifically, the present invention relates to a lighting module comprising a projection assembly with a primary lens capable of limiting chromatic aberrations generated within a light beam emitted by the lighting module.

[0002] Vehicles, and in particular motor vehicles, are commonly equipped with headlights to generate various lighting functions, such as road illumination or vehicle signaling. To achieve this, motor vehicle headlights are equipped with light modules, each comprising at least one light source configured to emit light beams, optical elements associated with said light source to collect and direct said light beams, and at least one projection assembly, for example, formed by a projection lens, configured to shape these collected and directed light beams and project them outwards from the headlight and the motor vehicle, forming a standard beam of light suitable for performing the lighting function.

[0003] It is particularly well-known in light modules operating in direct imaging, and comprising a projection system with a primary lens and a secondary lens arranged one after the other along an optical axis, approximately centered on this optical axis. Rays emitted by a light source connected to these primary and secondary lenses pass successively through each of said lenses. Such an arrangement is particularly efficient and compact for performing various lighting functions, notably for generating a vehicle's headlight beam.

[0004] However, in certain situations, the light beam generated by the light module may exhibit chromatic aberrations at one of its peripheries. Such chromatic aberrations occur when the different wavelengths of white light do not converge at the same focal point after passing through the lens(es) of the projection system. These chromatic aberrations result from the dispersion of wavelengths according to the refractive index of the lens(es) of the projection system through which the light passes, and manifest as an overintensity of a given wavelength at a peripheral edge of the light beam.

[0005] The present invention falls within this context and proposes to provide a light module in which chromatic aberrations are treated so as to limit the overintensity of a given wavelength in at least a part of the light beam projected by the light module.

[0006] Thus, the present invention relates to a light module for a motor vehicle intended to project a beam of light, the light module comprising at least one light source and a projection assembly comprising a primary lens and a secondary lens, the at least one light source being configured to generate light rays emitted towards the projection assembly, the projection assembly being configured to project the light rays emitted by the at least one light source outwards from the light module along an optical axis, the light rays emitted by the at least one light source passing successively through the primary lens and then through the secondary lens of the projection assembly, the primary lens comprising an entrance face at which the light rays emitted by the at least one light source reach the primary lens and an exit face opposite to the entrance face,the exit face of the primary lens having a first curvature around a first axis parallel to a first direction and a second curvature around a second axis parallel to a second direction, the first axis being perpendicular to the second axis, the primary lens comprising a plurality of optical structures arranged on a treated portion of the exit face of the primary lens.

[0007] The lighting module is an embedded component, for example, in a motor vehicle's headlight, designed to perform at least one lighting and / or signaling function. To this end, the lighting module comprises at least one light source for generating light beams and a projection system for optically processing these light beams and projecting a standard beam of light.

[0008] More specifically, the light module forms a direct imaging system with two projection lenses, the primary lens and the secondary lens, combined within the projection assembly. The primary and secondary lenses perform distinct functions within the light module. The primary lens is primarily configured to collimate the light rays emitted by at least one light source, while the secondary lens is primarily configured to shape the light beam to be projected onto the road in front of the vehicle.

[0009] The primary lens has an entrance face through which the light rays emitted by at least one light source directly reach the primary lens, i.e. no other element of the module is interposed between the primary lens and at least one light source, and an exit face through which the light rays emitted by at least one light source leave the primary lens to reach the secondary lens.

[0010] It is important to note that the primary lens and the secondary lens are two separate projection lenses. It is understood that the primary and secondary lenses are neither joined nor made of the same material. Furthermore, the primary and secondary lenses can be made of two different materials with different refractive indices.

[0011] At least one of the primary lens's exit surfaces has specific curvatures around two distinct and perpendicular axes. These specific curvatures of the primary lens's exit surface allow the light rays emitted by at least one light source to be split so that a larger area of ​​the secondary lens receives the light rays emitted by that source. The first direction corresponds to a vertical direction when the light module is fitted to a motor vehicle. The second direction corresponds to a transverse direction when the light module is fitted to a motor vehicle.

[0012] As mentioned, according to the invention, the exit face of the primary lens comprises optical structures arranged on a coated portion. These optical structures limit the overrepresentation, within the same area of ​​the light beam projected by the light module, of light rays that would cause chromatic aberration if these optical structures were not present. The optical structures are formed from the same material as the primary lens.

[0013] This chromatic aberration corresponds to an intrinsic optical defect inherent in the characteristics of optical systems. More specifically, within the meaning of the invention, chromatic aberration is an optical defect that occurs when the projection system is unable to focus all wavelengths of the visible spectrum to the same point. In a two-lens light module lacking optical structures specifically designed for this purpose, such chromatic aberration leads to the formation of colored fringes at the periphery of the light beam projected by the light module. The presence of optical structures, specifically located on the exit face of the primary lens, prevents the occurrence of these chromatic aberrations or at least reduces their impact on the quality of the projected light beam.

[0014] Optical structures are refractive structures configured to deflect light rays by changing their refractive index as they pass through the interface formed by the exit surface. More precisely, each optical structure exhibits a macroscopic local curvature, for example, a torus shape, which defines a law governing the variation of the angle of incidence of the light rays as a function of their point of impact on the treated area. This configuration induces refraction according to Snell's law, thereby redistributing the light rays in a controlled manner before their interception by the secondary lens.

[0015] This exploitation of the refractive properties of the structures makes it possible to solve the problem of chromatic aberrations by performing a targeted vertical spreading of the light rays, particularly at the beam cutoff. By acting directly on the wavefront through refraction, the invention makes it possible to homogenize the colorimetry of the projected beam and to attenuate colored fringes without introducing uncontrolled optical distortions.

[0016] The optical structures are specifically arranged on the exit face of the primary lens. In other words, only the exit face of the primary lens comprises the optical structures according to the invention, namely, the optical structures designed to be traversed by the majority of light rays likely to generate chromatic aberration. Indeed, an arrangement of the optical structures on the entrance face of the primary lens or on any of the entrance or exit faces of the secondary lens tends to degrade the quality of the light function generated by the light module.More specifically, the inventors determined that positioning these optical structures on the entrance face should be avoided because the light rays arriving in this area have not yet passed through any diopters exiting the light source and are too tightly grouped regardless of their wavelength. Therefore, optical structures positioned on this entrance face of the primary lens would impact too many rays that are not the cause of potential chromatic aberrations. Conversely, the inventors determined that positioning these optical structures on one of the faces of the secondary lens should be avoided because the light rays arriving in this area are spread over such a large surface that it would require a vast array of optical structures to process the majority of rays potentially causing chromatic aberrations.In other words, an arrangement of optical structures on the secondary lens would lead to processing too large a portion of light rays, and in particular light rays not responsible for chromatic aberration, which would degrade the resolution, i.e. the sharpness, of the light beam as well as its luminous intensity.

[0017] According to one feature of the invention, the coating area represents at most 25% of the surface area of ​​the primary lens's exit face. By limiting the area of ​​the coating area relative to the total surface area of ​​the primary lens's exit face, the number of light rays emitted by at least one light source and passing through the coating area is limited. It has thus been determined that by limiting the area of ​​the coating area to at most 25% of the total surface area of ​​the exit face, it is ensured, firstly, that a sufficient number of the light rays most likely to cause chromatic aberration are deflected by the optical structures to effectively minimize chromatic aberrations, and secondly, that a large number of the light rays emitted by the source are not deflected by these optical structures and that the luminous function generated by the light module is not unduly degraded.

[0018] According to one feature of the invention, the processing section extends from a first lateral edge of the output face to a second lateral edge of the output face, the first lateral edge being opposite the second lateral edge in the second direction. This arrangement of the processing section from one lateral end of the output face to an opposite lateral end makes it possible to optically treat light rays responsible for the same chromatic aberration over the entire transverse dimension of the light beam projected by the light module.

[0019] According to one feature of the invention, the optical structures of the processing section are arranged side by side to form at least one line extending from the first lateral edge to the second lateral edge. This linear arrangement of optical structures allows for the processing of light rays responsible for chromatic aberration along the entire lateral dimension of the primary lens. Furthermore, by adjusting the number of lines of optical structures, it is possible to control the shape of these structures in order to limit the generation of optical defects visible to the user.

[0020] According to one feature of the invention, the exit face of the primary lens has, on either side of the coated portion, along the first direction, a part distinct from the coated portion. It should be noted that "a part distinct from the coated portion" means that this "distinct part" forms a portion of the exit face of the primary lens that does not contain any optical structures. By way of example, this "distinct part" may be a smooth portion of the exit face of the primary lens that has no asperities other than those resulting from the manufacturing of the primary lens.In other words, the processing part extends transversely at a distance from each of the vertical ends, i.e. the opposite ends along the first direction, so that a separate part of the processing part, devoid of optical structures within the meaning of the invention, is in contact with said vertical ends.

[0021] According to one feature of the invention, the optical structures have a curved shape. This curved shape resembles a portion of a torus and, in particular, allows the optical structures to have a divergent configuration that distributes the light rays emitted by at least one light source along a component parallel to the first direction, i.e., vertically. Thus, the light rays, which could cause chromatic aberration in the absence of the optical structures, are distributed vertically within the light beam, and this distribution prevents the appearance of chromatic aberration in the beam. This curved shape can be concave, convex, or sinusoidal.

[0022] According to one feature of the invention, the convex shape of the optical structures has a first radius of curvature around a vertical axis of curvature parallel to the first axis, and a second radius of curvature around a lateral axis of curvature parallel to the second axis. The curvature obtained along the first radius of curvature, by juxtaposing the corresponding curvatures of each optical structure one after the other along a lateral direction, follows the curvature of the exit face of the primary lens, while the curvature obtained along the second radius of curvature is made more pronounced to achieve the desired function of deviating light rays and thus dispersing, in the vertical dimension, the rays that could generate chromatic aberration without an optical device.

[0023] According to one feature of the invention, the optical structures extend over a first distance measured along the first direction and over a second distance measured along the second direction, the first and second distances being substantially equal. These substantially equal distances allow an optical structure to fit within a cube. In other words, the projection of an optical structure onto a vertical screen placed opposite the light module forms substantially a square. Thus, the optical structures can follow the curvature of the exit face of the primary lens without causing excessive deviation of the light rays along the first direction.

[0024] According to one feature of the invention, the optical structures are refractive structures. These optical structures are thus configured to deflect light rays passing through the refraction processing part according to Snell's law.

[0025] According to one feature of the invention, the optical axis of the projection assembly is offset along the first direction relative to the processing section. By offsetting the processing section relative to the optical axis, on the one hand, the degradation of the light function generated by the light module is limited, and on the other hand, it is ensured that the optical structures are positioned along the path of rays emitted by at least one light source and responsible for chromatic aberration.

[0026] According to one feature of the invention, the exit face of the primary lens comprises a single treated part.

[0027] According to one feature of the invention, the exit face of the primary lens comprises a plurality of coatings distributed on either side of the optical axis of the projection assembly along the first direction. This plurality of coatings can be configured either to treat a plurality of chromatic aberrations or to correct a single chromatic aberration. Again, the coatings are not positioned on the optical axis, so as not to unduly affect the shape of the projected light beam as considered independently of the presence of the optical structures. It should be noted that the plurality of coatings can also be considered along the second direction.

[0028] According to one feature of the invention, the treatment part forms a part of the exit face of the primary lens through which passes a dominant set of light rays emitted by at least one light source and responsible for chromatic aberration in a light beam projected by the light module in the absence of said optical structures.

[0029] According to one feature of the invention, the chromatic aberration is blue. It is understood that the chromatic aberration forms on the light beam projected by the light module, in the absence of optical structures, one or more zones where the light beam is essentially formed by light rays with wavelengths between 400 nm and 480 nm.

[0030] According to one feature of the invention, said chromatic aberration is located at a periphery of the light beam projected by the light module in the absence of optical structures.

[0031] According to one feature of the invention, the secondary lens has an incident face through which the light rays emitted by at least one light source reach the secondary lens and an emergent face opposite the incident face. The incident face of the secondary lens comprises a plurality of optical elements on at least a portion of said incident face. The optical elements are distinct from the optical structures and are formed from the same material as the secondary lens. These optical elements homogenize the light beam projected by the secondary lens.

[0032] According to one feature of the invention, the entire incident face of the secondary lens comprises optical elements.

[0033] According to one feature of the invention, the light module comprises a plurality of light sources aligned with each other along the second direction.

[0034] According to one feature of the invention, each optical structure comprises its own edges, the edges of the optical structures being arranged edge to edge.

[0035] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and the illustrative and non-limiting examples of embodiments given with reference to the attached schematic drawings on the other hand, in which:

[0036] schematically represents an exploded view of a light module according to the present invention, the light module comprising a primary lens provided with optical structures and a secondary lens;

[0037] schematically represents an exit face of the primary lens on which the optical structures are made;

[0038] schematically represents a path of light rays responsible for a chromatic aberration in a light beam projected by a prior art light module, devoid of optical structures within the meaning of the invention;

[0039] schematically represents a path of light rays similar to that of the, for a light module according to the invention with optical structures formed on an exit face of the primary lens, the optical structures having distributed said light rays vertically;

[0040] schematically represents a more detailed view of the optical structures allowing to highlight a radius of curvature of said optical structures.

[0041] The features, variants, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may include only a selection of features, described hereafter in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0042] In the figures, elements common to several figures retain the same reference.

[0043] In the detailed description that follows, the terms "longitudinal," "transverse," or "lateral," and "vertical" refer to the orientation of the light module according to the invention. A longitudinal direction corresponds to the direction of travel of a vehicle equipped with the light module, this longitudinal direction being parallel to a longitudinal axis L of a frame of reference L, V, T illustrated in the figures. A transverse, or lateral, direction corresponds to a direction perpendicular, in a horizontal plane, to the direction of travel of the vehicle equipped with the light module, this transverse or lateral direction being parallel to a transverse axis T of the frame of reference L, V, T, and this transverse axis T being perpendicular to the longitudinal axis L. Finally, a vertical direction corresponds to a direction parallel to a vertical axis V of the frame of reference L, V, T, this vertical axis V being perpendicular to the longitudinal axis L and to the transverse axis T.

[0044] Figure 1 illustrates a light module 2 according to the present invention. The light module 2 is intended for use in a motor vehicle. The light module 2 comprises a housing, not shown in the figures, in which are housed at least one light source 4, visible in particular in Figure 1, and a projection assembly 6.

[0045] The light module 2 forms a direct imaging system with two projection lenses. The projection assembly 6 comprises a primary lens 8 and a secondary lens 10. The primary lens 8 and the secondary lens 10 are made of two distinct materials with different refractive indices. More specifically, in the embodiment shown, the primary lens 8 is made of polycarbonate (PC) and the secondary lens 10 is made of polymethyl methacrylate (PMMA).

[0046] At least one light source 4 is configured to emit light rays towards the projection assembly 6. The at least one light source 4 is arranged on a support 12 located upstream of the primary lens 8. In the embodiment shown, the support 12 includes all the electronic elements enabling the function of the at least one light source 4. In the embodiment shown, the light module 2 includes a plurality of light sources 4 aligned with each other along a support wall 14 of the support 12.

[0047]

[0048] The projection assembly 6 is configured to project the light rays emitted by at least one light source 4 outwards from the light module 2 along an optical axis 16, visible in particular on the diagram. The optical axis 16 passes substantially through the optical center of the primary lens 8 on one side and through the optical center of the secondary lens 10 on the other.

[0049] The primary lens 8 forms the lens of the projection assembly 6 placed closest to at least one light source 4. This primary lens 8 is configured to collect and direct the light rays emitted by at least one light source 4 towards the secondary lens 10. The primary lens 8 has an object focal point located near at least one light source and it has an image focal point which can advantageously be located at the object focal point of the secondary lens 10.

[0050] The secondary lens 10 forms the lens of the projection assembly 6, positioned furthest from at least one light source 4. The secondary lens 10 is configured to project the light rays collimated by the primary lens 8 and form a standard beam of light. In other words, the light rays emitted by the at least one light source pass successively, along the optical axis 16, through the primary lens 8 and then through the secondary lens 10.

[0051] In the embodiment shown, the light beam formed by the light module 2 provides a lighting function, and more specifically, a lower portion of a regulatory light beam. It should be noted that the present invention applies both to such a light beam and to a lighting function intended to form either an entire regulatory beam or the upper portion of a regulatory beam.

[0052] In addition, the primary lens 8 comprises an entrance face 18 and an exit face 20 opposite the entrance face 18. The entrance face 18 forms the face of the primary lens 8 through which the light rays emitted by at least one light source 4 reach the primary lens 8. The exit face 20 forms the face of the primary lens 8 through which the light rays emitted by at least one light source 4 leave the primary lens 8 in the direction of the secondary lens 10.

[0053] The secondary lens 10 comprises an incident face 22 and an emergent face 24 opposite the incident face 22. The incident face 22 forms the face of the secondary lens 10 through which the light rays emitted by at least one light source 4, and more particularly collimated by the primary lens 8, reach the secondary lens 10. The emergent face 24 forms the face of the secondary lens 10 through which the light rays emitted by at least one light source 4 are projected and shaped by the secondary lens 10 to form all or part of a regulatory beam.

[0054] It is understood from the above that the light rays emitted by at least one light source 4 pass successively through the primary lens 8 and then through the secondary lens 10. More specifically, the light rays emitted by at least one light source pass successively through the entrance face 18 of the primary lens 8, the exit face 20 of the primary lens 8, the incident face 22 of the secondary lens 10 and then the emergent face 24 of the secondary lens 10. According to the invention and as will be described in more detail in the following description, some of the light rays passing through the exit face 20 of the primary lens 8 pass through optical structures 38 made on a part of the exit face 20 of the primary lens 8.

[0055] As shown in Figure 1, the exit face 20 of the primary lens 8 exhibits a first curvature about a first axis 26 parallel to a first direction. The exit face 20 of the primary lens 8 also exhibits a second curvature about a second axis 28 parallel to a second direction, the first axis 26 being perpendicular to the second axis 28. It should be noted that, as shown in Figure 1, the first axis 26 is parallel to the vertical axis V and the second axis 28 is parallel to the transverse axis T. Furthermore, it should be noted that the positions of the first axis 26 and the second axis 28 as shown in Figure 1 are given for illustrative purposes only and are intended to indicate their direction relative to the primary lens 8.

[0056] As mentioned and as can be seen in particular in figures 1 and 2, the light module according to the invention is particular in that the exit face 20 of the primary lens 8 includes a treatment part 30. This treatment part 30 of the exit face 20 is configured to treat light rays emitted by at least one light source 4 and which would be responsible for chromatic aberration on a light beam projected by the light module 2 in the absence of said treatment part 30.

[0057] More specifically, it represents a light module 2 on which the primary lens 8 is devoid of a coating part 30. The inventors were able to determine the origin of a chromatic aberration in the periphery of the light beam projected by the light module 2 and identify light rays 32 responsible for said chromatic aberration.

[0058] The light ray tracing identified on this diagram makes it visible that a dominant portion—for example, greater than 50% and preferably greater than 60%—of the light rays responsible for chromatic aberration passes through targeted areas on each entrance and exit face of the lenses, specifically through a first area 34 of the primary lens 8 and a second area 36 of the secondary lens 10. In this context, the inventors were able to determine that the area impacted by the passage of light rays is smaller on the exit face 20 of the primary lens 8 than on the emergent face 24 of the secondary lens. Therefore, it is preferable to position optical structures 38 on the exit face 20 of the primary lens 8 so that the impact on light rays that are not responsible for chromatic aberration and that are likely to pass through these same areas is reduced.

[0059] Thus, the inventors were able to determine that the implementation of a treatment part 30 on the exit face 20 of the primary lens 8 at the level of a part of this exit face 20 through which passes a dominant part of the light rays responsible for the chromatic aberration makes it possible to strongly limit this chromatic aberration on the light beam projected by the light module 2.

[0060] More specifically, the processing area 30 is formed, as shown in Figures 1 and 2, by a plurality of optical structures 38. To limit the impact of these optical structures 38 on the light function generated by the light module 2, the optical structures 38 are arranged at the level of the portion of the exit face 20 through which the dominant part of the light rays responsible for the chromatic aberration mentioned above passes. To limit this impact of the optical structures 38 on the light function, the processing area 30 represents at most 25% of the area of ​​the exit face 20 of the primary lens 8.

[0061] As can be seen in particular in the figure, the treated portion 30 extends along the exit face 20 of the primary lens 8 from a first edge 40 of the exit face 20 to a second edge 42 of the exit face 20, the first edge 40 and the second edge 42 being opposite each other along the second direction. In other words, the first edge 40 and the second edge 42 are each located at a transverse end of the exit face 20, and the treated portion 30 extends along a main transverse elongation direction, here from one edge to the other of the exit face.

[0062] The optical structures 38 of the processing part 30 are distributed next to each other to form at least one line 44 extending along the transverse direction, or second direction, as mentioned, where appropriate from the first edge 40 to the second edge 42. It should be noted that the optical structures 38 are arranged edge to edge next to each other.

[0063] The positioning of the processing part 30 on the exit face 20 of the primary lens 8 is such that the exit face 20 presents, on either side of the processing part 30, along the first direction, a portion distinct from the processing part 30. As can be seen in Figures 1, 2 and 4, the processing part 30 extends along the first direction, at a distance from each vertical end edge, with an area devoid of optical structures 38 interposed between one end and the processing part 30. This results, as can be seen in Figures 1, 2 and 4, in an alternation, along the first direction, between the processing part 30 and distinct portions of the processing part 30, i.e., portions devoid of optical structures 38.

[0064] Optical structures 38 are refractive structures that allow light rays to be deflected when they reach the exit face 20 of the primary lens 8, which forms a diopter.

[0065] The optical structures 38 thus differ from prior art solutions based on diffraction gratings. In these diffractive systems, the grating acts on the different colored components of light, like a prism, to try to compensate for the chromatic aberrations of the lens. Conversely, the optical structures 38 of the present invention form macroscopic profile variations on the surface of the primary lens 8, defining a plurality of local diopters. In particular, the optical structures 38 have dimensions on the order of a millimeter.

[0066] Each optical structure 38 deflects the path of the light rays that reach it by refraction, locally blurring the sharp image of the colored cutoff and thus desaturating the final color of the projected beam. This deterministic control of refraction ensures the spreading of the light rays responsible for chromatic aberration, thereby reducing or even eliminating the perception of colored fringes at the cutoff, while guaranteeing maximum transmission efficiency and greater industrial robustness compared to diffractive solutions.

[0067] The optical structures 38 have a convex shape configured to vertically distribute the light rays passing through the processing section 30. Indeed, as can be seen by comparing Figures 3 and 4, the light rays emitted by at least one light source 4 and passing through the processing section 30 are refracted so as to be distributed vertically over a larger area of ​​the secondary lens 10, towards which the rays are directed as they exit the primary lens. This distribution of the light rays passing through the processing section 30 allows the light rays responsible for chromatic aberration to diverge throughout the light beam, so that these light rays are not focused on a single part of the light beam projected by the light module 2.

[0068] The convex shape of the optical structures 38 more specifically resembles a portion of a torus. This particular shape of the optical structures 38 is especially visible on the diagram. It is understood that the convex shape of the optical structures 38 has a first radius of curvature around a vertical axis of curvature, substantially parallel to the first axis 26, and a second radius of curvature 39 around a lateral axis of curvature 41, substantially parallel to the second axis 28 and substantially perpendicular to the lateral axis of curvature. The term "substantially" should be understood in relation to the parallelism and perpendicularity of the axes with respect to each other, and manufacturing tolerances must be taken into account.It should be noted that in alternative embodiments of the invention, the optical structures 38 may have a concave shape or even both convex and concave as long as this shape allows for a vertical spreading of the light rays passing through said optical structures 38.

[0069] The optical structures 38, with their torus-like shape, are adapted to follow the complex curve of the exit face 20 of the primary lens 8, which, as previously mentioned, has a first and a second curvature. More specifically, regarding the convex shape of the optical structures 38, the first radius of curvature of the optical structures 38 is greater than the second radius of curvature of said optical structures 38. This particular shape of the optical structures 38 allows the light rays passing through them to be distributed vertically, that is, distributed along a component parallel to the first axis 26.

[0070] To properly follow these first and second curvatures, the optical structures 38 extend over a first distance D1 measured along the first direction and a second distance D2 measured along the second direction, which are approximately equal. This characteristic of the dimensions of the optical structures is such that the shape of the optical structures 38 can follow both the first and second curvatures without forming an excessively pronounced profile that would degrade the luminous function.

[0071] In order to avoid degrading the light function generated by the light module, the processing part 30 is offset along the first direction relative to the optical axis 16 of the projection assembly 6. This offset of the processing part 30 relative to the optical axis 16 makes it possible to limit the degradation of the light function generated by the light module 2 by avoiding positioning optical structures 38 in an area where the light rays are only slightly deviated and contribute to forming a clear portion of the light beam generated by the light module 2.

[0072] In addition, the exit face 20 of the primary lens 8 comprises, in the embodiment shown, a single treated part 30. This single treated part 30 must be considered in that the optical structures 38 are arranged edge to edge with each other or, where appropriate, with a non-significant gap resulting from the manufacturing process.

[0073] Alternatively, the exit face 20 of the primary lens 8 may comprise a plurality of processing parts 30. In such a configuration of the exit face 20 of the primary lens 8 with a plurality of processing parts 30, these processing parts 30 are advantageously distributed on either side of the optical axis 16 of the projection assembly 6 in the first direction, i.e. vertically.

[0074] It should be noted that the position of the optical structures on the output face, as illustrated in Figures 1, 2, and 4, represents an embodiment in which a certain type of light ray and the chromatic aberration they are likely to generate are processed by the optical structures. More specifically, in the embodiment shown, the chromatic aberration in question is responsible for a blue area at the periphery of the light beam due to the presence of a majority of light rays with wavelengths between 400 nm and 480 nm.If necessary, the treatment area could extend, still on the exit face of the primary lens, to different distances and over a different vertical angular portion to treat another wavelength of light rays and the chromatic aberration they are likely to generate, it being understood that it remains advantageous in this case to have an extent of the treatment area less than 25% of the extent of the exit face of the primary lens and to have a vertical offset of the treatment area relative to the optical axis.

[0075] The secondary lens 10, and more specifically the incident face 22 of the secondary lens 10, comprises, as can be seen in the figure, optical elements 46 on at least a portion of the incident face 22. These optical elements 46 are distinct from the optical structures 38 and perform a different function. Indeed, the optical elements 46 are designed to improve the homogeneity of the light beam projected by the light module 2, whereas the optical structures 38 are designed to distribute the light rays passing through them along the first direction, that is, vertically. To this end, unlike the optical structures 38, the optical elements 46 have a curvature along the first direction and a curvature along the second direction, the radius of curvature of which is substantially equal in both directions.

[0076] Advantageously, the incident face 22 of the secondary lens 10 includes optical elements 46 over its entire surface to further improve the homogeneity of the light beam.

[0077] The present invention achieves its objective by proposing a light module capable of correcting visible chromatic aberrations on the light beam projected by the light module by means of a processing part comprising optical structures made on the output face of a primary lens of the light module.

[0078] The present invention is not limited to the means and configurations described and illustrated herein, and also extends to any equivalent means and configuration as well as any technically operative combination of such means.

Claims

light module (2) for a motor vehicle intended to project a beam of light, the light module (2) comprising at least one light source (4) and a projection assembly (6) comprising a primary lens (8) and a secondary lens (10), the at least one light source (4) being configured to generate light rays emitted towards the projection assembly (6), the projection assembly (6) being configured to project the light rays emitted by the at least one light source (4) outwards from the light module (4) along an optical axis (16), the light rays emitted by the at least one light source (4) passing successively through the primary lens (8) and then through the secondary lens (10) of the projection assembly (6),the primary lens (8) comprising an entrance face (18) at which the light rays emitted by at least one light source (4) reach the primary lens (8) and an exit face (20) opposite the entrance face (18), the exit face (20) of the primary lens (8) having a first curvature about a first axis (26) parallel to a first direction and a second curvature about a second axis (28) parallel to a second direction, the first axis (26) being perpendicular to the second axis (28), the primary lens (8) comprising a plurality of optical structures (38) arranged on a coated portion (30) of the exit face (20) of the primary lens (8). Light module (2) according to claim 1, wherein the treatment part (30) represents at most 25% of the area of ​​the exit face (20) of the primary lens (8). Light module (2) according to any one of claims 1 and 2, wherein the processing part (30) extends from a first lateral edge (40) of the output face (20) to a second lateral edge (42) of the output face (20), the first lateral edge (40) being opposite the second lateral edge (42) along the second direction. Light module (2) according to any one of claims 1 to 3, wherein the exit face (20) of the primary lens (8) has on either side of the treatment part (30), along the first direction, a part distinct from the treatment part (30). Light module (2) according to any one of claims 1 to 4, wherein the optical structures (38) have a curved shape. Light module (2) according to any one of claims 1 to 5, wherein the convex shape of the optical structures (38) has a first radius of curvature around a vertical axis of curvature parallel to the first axis (26) greater than a second radius of curvature around a lateral axis of curvature parallel to the second axis (28). Light module (2) according to any one of claims 1 to 6, wherein the optical structures (38) are refractive structures. Light module (2) according to any one of claims 1 to 6, wherein the optical axis (16) of the projection assembly (16) is offset along the first direction relative to the processing part (30). Light module (2) according to any one of claims 1 to 7, wherein the exit face (20) of the primary lens (8) comprises a single treated part (30). Light module (2) according to any one of claims 1 to 7, wherein the exit face (20) of the primary lens (8) comprises a plurality of coating parts (30) distributed on either side of the optical axis (16) of the projection assembly (6) along the first direction. Light module (2) according to any one of claims 1 to 9, wherein the treatment part (30) forms part of the exit face (20) of the primary lens (8) through which passes a dominant set of light rays (32) emitted by at least one light source and responsible for chromatic aberration in a light beam projected by the light module in the absence of said optical structures (38). Light module (2) according to claim 10, wherein the chromatic aberration is blue. Light module (2) according to any one of claims 10 and 11, wherein said chromatic aberration is located at a periphery of the light beam projected by the light module (2) in the absence of optical structures (38). Light module (2) according to any one of claims 1 to 12, wherein the secondary lens (10) has an incident face (22) through which the light rays emitted by at least one light source reach the secondary lens (10) and an emergent face (24) opposite the incident face (22), the incident face (22) of the secondary lens (10) comprising a plurality of optical elements (46) on at least a part of said incident face (22), preferably on the entirety of said incident face (22). Light module (2) according to any one of claims 1 to 13, wherein the light module (2) comprises a plurality of light sources (4) aligned with each other along the second direction. Light module (2) according to any one of claims 1 to 14, wherein each optical structure (38) comprises its own edges, the edges of the optical structures (38) being arranged edge to edge.

Images