Motor vehicle lighting system

Abstract

The invention relates to a lighting system for a motor vehicle, comprising: - a light source (21); - a collimating optic (22) collimating the light rays (RL) emitted by the light source (21) in a collimation direction (O1); - a transparent optical element (1) comprising an entrance face (11) that comprises: - pass-through portions (111) extending in parallel planes of extension perpendicular to the collimation direction, and offset from one another in the collimation direction, wherein the pass-through portions transmit the collimated light rays (RL1) towards the exit face (12); and - deflection portions (112) that join the pass-through portions, and extend substantially parallel to the collimation direction, wherein the deflection portions reflect or scatter a majority of the direct light rays, such that the majority of the direct light rays do not reach the exit face (12).

Description

Description Title of the invention: Motor vehicle lighting system

[0001] The technical context of the present invention is that of motor vehicle lighting systems. In particular, the present invention falls within the context of lighting and / or signaling devices for motor vehicles. [2] In the state of the art, lighting systems are known, in particular lighting and / or signaling systems comprising: - a LED type light source - English acronym meaning Light Emitting Diode which can be translated as "Electroluminescent Diode" - a reflector for collimating light rays generated by the light source; and - an optical element, through which the collimated light rays are transmitted outwards. [3] In such known lighting and / or signaling systems, the reflector is, for example, of the type of a parabolic reflector and the light source is arranged at the focus of the reflector. Thus, the reflector collimates the light rays emitted by the light source. The collimated light rays are then shaped and transmitted by the optical element in order to generate a light beam which can, for example, contribute to a signaling function. [4] A known disadvantage of such lighting and / or signaling systems lies in the fact that some of the light rays emitted by the light source are not collected by the reflector. Indeed, some of the light rays emitted by the light source are directly emitted towards the optical element. These light rays, called direct light rays, are not collimated and thus form illumination inhomogeneities at the optical element, and in particular at the exit face of the optical element. In other words, these direct light rays create hot spots, otherwise called high intensity points, which are parasitic in the formed light beam and on the exit face of the optical element. The appearance of the light beam and the appearance of the exit face of the optical element are then not satisfactory, because they are not sufficiently homogeneous. [5] In order to limit the appearance of such hot spots on the optical element, it is known to position a screen between the light source and the optical element. Such a screen thus makes it possible to cut off the light rays emitted by the light source and which are emitted directly towards the optical element. However, by cutting off these direct light rays, the screen then creates dark areas on the optical element, and in the light beam formed. Indeed, the screen creates a shadow on the optical element, and in particular on the exit face of the optical element. These dark areas on the optical element deteriorate the lit appearance of the optical element, and in particular of its exit face. In addition, the light beam transmitted by the optical element still does not appear sufficiently homogeneous. [6] The present invention aims to propose a motor vehicle lighting system making it possible to respond at least to a large extent to the preceding problems and also to lead to other advantages. [7] In particular, the present invention aims to propose a lighting system making it possible to improve the illuminated appearance of the output face of an optical element and in particular its homogeneity, and to improve the homogeneity of the light beam transmitted by the optical element. [8] Another object of the invention is to provide a lighting system in which the presence of hot spots or shadow zones on the output face of such an optical element, and in the transmitted light beam, is limited. [9] According to a first aspect of the invention, the invention provides a motor vehicle lighting system intended to emit a light beam, comprising: - at least one light source configured to emit light rays; - a collimation optic configured to collimate the light rays emitted by the at least one light source according to a collimation direction; - a transparent optical element comprising an input face and an output face, arranged opposite the input face, the optical element being intended to transmit said light beam, the input face comprising: • passing parts each extending in an extension plane, the extension planes being parallel, extending perpendicular to the collimation direction, and being offset from each other according to the collimation direction, said passing parts being configured to transmit the collimated light rays towards the output face; and • deflection portions joining the passing portions, and extending substantially parallel to the collimation direction, the deflection portions being configured to reflect and / or diffuse a majority of the light rays emitted by the light source and not collimated by the collimation optics, so that said majority of the light rays emitted by the light source and not collimated are returned out of the output face.

[0010] In the context of the present invention, the optical element is configured to allow transmission of certain light rays between its input face and its output face. The optical element is in particular transparent to light rays used in the automotive field, that is to say in particular those having a wavelength included in a spectrum visible to a human eye, that is to say whose wavelength is between 400 nm and 700 nm.

[0011] In the context of the present invention, the optical element is configured to orient the incident light rays passing through the input face, and in particular the passing portions, in a predetermined direction in order to form a light beam beyond the output face. In a first example, the optical element may be a lens. In this first example, a direction of propagation of the light rays beyond the output face is different from the direction of propagation of said light rays arriving on the input face. Alternatively, the optical element may be an element optically neutral with respect to the incident light rays passing through the passing portions towards the output surface.In this case where the optical element is optically neutral, then a direction of propagation of the light rays beyond the exit face is identical to the direction of propagation of said light rays arriving on the entry face.

[0012] In the context of the present invention, the output face is located downstream of the input face, relative to a direction of propagation of the light rays through the optical element, and in particular relative to the direction of collimation.

[0013] In the context of the present invention, the passing parts are configured to transmit incident light rays that propagate perpendicularly or substantially perpendicularly to their plane of extension. In the present invention, these incident light rays that propagate perpendicularly or substantially perpendicularly to their plane of extension correspond to light rays propagating parallel or substantially parallel to the collimation direction, and therefore to light rays that have been collimated by the collimation optics. It is understood that a light ray extends parallel or substantially parallel to the collimation direction, if it has an angle less than or equal to 10° or 20° relative to the collimation direction.In the context of the present invention, a light ray incident on one of the passing parts is transmitted or refracted by said passing part, and propagates in the optical element towards the exit face.

[0014] In the context of the present invention, it will be understood that the through portions are disjoint and spaced apart from each other. In particular, the through portions form stepped surfaces relative to each other. The deflection portions extend between two directly adjacent through portions.

[0015] The deflection portions form peripheral walls to the through portions. In particular, the deflection portions extend around and between two through portions. In other words, the deflection portions form contours of the through portions.

[0016] In the context of the invention, a light ray emitted by the source and collimated by the collimating optics is returned by the collimating optics parallel to the collimation direction. The light rays collimated by the collimating optics are therefore light rays parallel to each other and to the collimation direction.

[0017] In the context of the invention, the light rays emitted by the light source and not collimated by the collimating optics are also called "direct light rays".

[0018] In the context of the invention, to say that light rays are reflected out of the exit face means that these light rays do not reach the exit face of the optical element. For example, the light rays may be reflected or diffused by the input face of the optical element, so that they do not reach the output face.

[0019] By the majority of the light rays emitted by the light source and not collimated are returned out of the exit face, it is meant that less than 50%, preferably less than 30%, even more preferably less than 10%, of the direct light rays are returned out of the exit face, in other words less than 50%, preferably less than 30%, even more preferably less than 10% of the direct light rays reach the exit face of the optical element.

[0020] Thanks to the invention, the light rays transmitted by the optical element correspond mainly to the light rays which have been collimated by the collimating optics. Indeed, the direct light rays which have not been collimated by the collimating optics and which directly reach the input face of the optical element will be mainly reflected or diffused by the deflection parts, outside the output face of the optical element. On the contrary, the light rays collimated by the collimating optics will only encounter the passing parts. Indeed, as the deflection parts extend parallel to the collimation direction, they do not intercept the collimated light rays. Thus, all of the collimated light rays enter the optical element via the passing parts, and are therefore transmitted by the optical element to the output face.

[0021] Thus, the light beam transmitted by the optical element is mainly formed by light rays that have been collimated by the collimating optics. In this case, the direct light rays constitute only a minority of the light rays that form the light beam. In addition, the few direct light rays that reach the exit face of the optical element and thus form the light beam are scattered by the entry face, and in particular the deflection parts of the entry face of the optical element. Thus, the direct light rays are distributed along the exit face. They therefore no longer form hot spots on the exit face of the optical element or in the light beam.

[0022] Furthermore, since the optical element is transparent, no dark area is formed on the exit face of the optical element and in the light beam.

[0023] Thus, using the structure of the input face comprising both passing parts and deflection parts, it is possible to obtain an output face which will be illuminated homogeneously, and a homogeneous light beam. In addition, this solution has the advantage of not requiring any additional parts. The optical element alone allows the illumination of the output face to be homogeneous, and the light beam to be homogeneous.

[0024] The lighting system may include one or more of the features below.

[0025] According to an alternative of the invention, the collimation direction corresponds to the direction of the optical axis of the light system. This collimation direction can also be called the longitudinal direction.

[0026] According to an alternative of the invention, the light beam transmitted by the optical element comprises at most 30%, preferably at most 10%, of light rays transmitted by the deflection parts. Since the deflection parts extend substantially parallel to the collimation direction, only direct light rays can reach the deflection parts. Thus, saying that the light beam transmitted by the optical element comprises at most 30%, preferably at most 10%, of light rays transmitted by the deflection parts means that the direct light rays transmitted by the optical element represent only 30%, respectively 10%, of the light rays forming the light beam. It is therefore understood that the presence of hot spots is avoided in the light beam, and on the exit face.

[0027] According to an alternative of the invention, the light beam transmitted by the optical element comprises at most 1% of light rays transmitted by the deflection parts. Thus, almost no direct light rays reach the output face and are transmitted by the optical element.

[0028] According to an alternative of the invention, none of the direct light rays reach the exit face. In other words, the optical element only allows the collimated light rays to pass through. In this case, the light beam is entirely formed by the collimated light rays. The homogeneity of the illumination of the exit face and the homogeneity of the light beam is further improved.

[0029] According to an alternative of the invention, the collimation optics comprises a reflector. Advantageously, the collimation optics comprises a reflector parabolic, and the light source is placed at the focus of the parabolic reflector. The parabolic reflector thus allows the light rays emitted by the light source to be collimated.

[0030] According to an alternative of the invention, the passing parts have a polygonal shape. Preferably, the passing parts have a quadrilateral or hexagon shape. These shapes make it possible to minimize the gaps between two adjacent passing parts.

[0031] According to an alternative of the invention, the pass-through portions all have an identical shape. Identical shape means that all the shapes of the pass-through portions have the same geometry and the same dimensions. Alternatively, the pass-through portions may have different shapes. Alternatively, the pass-through portions may all have the same shape but different dimensions depending on their position along the entry surface of the optical element.

[0032] According to an alternative of the invention, the pass-through portions are smooth. Preferably, the pass-through portions have a roughness index of less than 1 μm. The pass-through portions may also be polished. This configuration makes it easier to transmit a light ray through the pass-through portions.

[0033] According to an alternative of the invention, the deflection parts have a roughness index greater than 100 pm. The roughness of the deflection parts makes it possible to participate in diffusing and / or reflecting light rays incident on the deflection parts.

[0034] According to an alternative of the invention, the deflection parts have a roughness greater than that of the passing parts.

[0035] According to an alternative of the invention, the deflection portions have an irregular surface condition. By irregular, it is understood that a general conformation of the deflection portion is variable depending on a position taken on said peripheral wall. For example, a topography of the deflection portions is random.

[0036] According to an alternative of the invention, each deflection portion comprises a periodic surface condition along at least one direction of the deflection portion. By periodic, it is understood that the surface condition of a given deflection portion comprises a repeated pattern along said deflection portion. This configuration advantageous makes it possible to facilitate the diffusion or reflection of a light ray incident on the deflection part.

[0037] According to an alternative of the invention, each deflection portion comprises at least one groove which extends rectilinearly along the collimation direction. For example, each at least one groove extends between a first passing portion and a second passing portion.

[0038] In the context of the present invention, a groove is understood to be a groove or a rib which extends rectilinearly along one of the deflection portions, the groove being able to take any shape. In particular, the at least one groove may have a circular or semi-circular or triangular or sinusoidal or trapezoidal transverse profile. For example, a transverse dimension of each at least one groove is between 0.1 mm and 1 mm, preferably equal to 0.2 mm.

[0039] According to an alternative of the invention, each deflection portion comprises a plurality of grooves. In particular, the grooves may be arranged side by side and each extend rectilinearly along the collimation direction.

[0040] According to an alternative of the invention, the light beam emitted by the optical element is a signaling beam, such as a position light, a daytime running light or a direction indicator light.

[0041] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0042] [Fig.1] Figure 1 illustrates a lighting system according to the invention, integrated into a partially represented motor vehicle lighting device;

[0043] [Fig.2] Figure 2 illustrates a schematic sectional view of the lighting system according to the invention;

[0044] [Fig.3] Figure 3 illustrates a detailed view of the lighting system illustrated in Figure 2;

[0045] [Fig.4] Figure 4 illustrates a first example of embodiment of an input surface of an optical element equipping the light system illustrated in Figures 1 to 3;

[0046] [Fig.5] Figure 5 illustrates a second example of the embodiment of an input surface of an optical element equipping the light system illustrated in Figures 1 to 3.

[0047] Of course, the features, variants and different embodiments of the invention can be combined with each other in various combinations, provided that they are not incompatible or mutually exclusive. In particular, all the variants and embodiments described can be combined with each other if there is no technical obstacle to this combination.

[0048] In the figures, elements common to several figures retain the same reference.

[0049] Figure 1 illustrates, in a partial three-dimensional view, a lighting device 3 of a motor vehicle, and more particularly a lighting and / or signaling device of a motor vehicle. The lighting device 3 may in particular be a front headlight of a motor vehicle or a rear light. The lighting device 3 comprises in particular a lighting system 2 according to the invention at its periphery. The lighting device 3 comprises other lighting elements 4 at its periphery. In this example, the lighting system 2, like the other lighting elements 4, participate in the realization of a signaling function, such as a position light function, a daytime running light function or a change of direction indication function.

[0050] Figures 2 and 3 illustrate more precisely the lighting system 2 according to the invention. In particular, Figure 2 shows a schematic sectional view of the lighting system 2 and Figure 3 schematically illustrates a detail of the lighting system 2. The lighting system 2 comprises a light source 21 configured to emit light rays RL, a collimation optic 22 configured to collimate a portion of the light rays RL emitted by the at least one light source 21 in a collimation direction 01, and an optical element 1 intended to transmit the light rays emitted by the light source 21 so as to form a light beam. The optical element 1 is configured to orient the incident light rays in a predetermined direction in order to form the light beam.

[0051] The light source 21 is preferably a light-emitting diode. In the example illustrated, the light system 2 comprises a single light source 21. It is understood that the light system 2 could comprise a plurality of light sources without departing from the scope of the invention. The arrangement and / or orientation of the light source 21 in the light system 2 leads to a portion of the light rays RL1 emitted by the light source 21 reaching the collimating optics 22 while the other portion of the light rays RL2 emitted by the light source 21 directly reaching the optical element 1 without passing through the collimating optics 22. These light rays RL2 then reach the optical element 1 in all directions.

[0052] The light rays RL1 emitted by the light source 21 and which reach the collimating optics 22 are called indirect light rays. The light rays RL2 emitted by the light source 21 and which directly reach the optical element 1 without passing through the collimating optics 22 are called direct light rays.

[0053] The collimation optics 22 are configured to collimate the light rays RL emitted by the at least one light source 21, and which reach it. Thus, the light rays RL1 emitted by the at least one light source 21 and reaching the collimation optics 22 are all returned parallel to each other and parallel to a collimation direction 01. The collimation direction 01 may in particular correspond to the direction of the optical axis of the light system 2. In the present invention, the collimation direction 01 corresponds to a longitudinal direction. These light rays RL1 then reach the optical element 1 along the collimation direction 01.

[0054] In the illustrated example, the collimation optics 22 comprises a parabolic reflector, and the light source 21 is arranged at the focus of the parabolic reflector. The indirect light rays RL2 are therefore returned parallel to the collimation direction 01 after reflection on the parabolic reflector, towards the optical element 1.

[0055] The optical element 1 comprises an input face 11 and an output face 12 arranged opposite the input face 11. The input face 11 faces the collimation optics 22. The output face 12 is located downstream of the input face 11, relative to the direction of propagation of the light rays through of the optical element 1, and in particular relative to the collimation direction 01.

[0056] The input face 11 of the optical element 1 comprises passing parts 111 and deflection parts 112 which are particularly visible in Figure 3.

[0057] As will be described later, the optical element 1 is configured to address the direct light rays RL2 differently from the indirect light rays RL1. In particular, the optical element 1 is configured to facilitate the transmission of the indirect light rays RL1 towards the exit face, and to prevent as much as possible the transmission of the direct light rays RL2 towards the exit face 12. This separate treatment of the indirect light rays RL1 and the direct light rays RL2 is enabled by means of the passing parts 1 11 and the deflection parts 1 12.

[0058] The pass-through portions 1 1 1 each extend in an extension plane. The extension planes of the pass-through portions 1 1 1 are parallel, and extend perpendicular to the collimation direction. In addition, the extension planes of the pass-through portions 1 1 1 are offset from each other along the collimation direction 01. Thus, the pass-through portions 1 1 1 are disjoint and distant from each other. The pass-through portions 1 11 form stepped surfaces relative to each other.

[0059] In the illustrated example, and as particularly visible in Figures 4 and 5, the passing parts 1 1 1 all have the same shape, namely that they all have a square shape. It is understood that the invention is not limited to this specific shape, and that the passing parts 1 1 1 could take another shape, for example any other polygonal shape, or more precisely a quadrilateral or hexagon shape, without departing from the scope of the invention. In addition, the passing parts 1 1 1 could have different shapes from each other, or different dimensions from each other.

[0060] The passing parts 1 1 1 are smooth. They preferably have a roughness index of less than 1 pm. They can also be polished.

[0061] The passing parts 1 1 1 make it possible to transmit the light rays RL1 emitted by the light source 21 and collimated by the collimating optics 22 towards the optical element 1 . Indeed, as the collimated light rays RL1 arrive perpendicular to the plane of extension of the passing parts 1 1 1 , they are transmitted by the passing parts 1 1 1 into the optical element 1 , without being deflected. These light rays then propagate in the optical element 1 towards the exit face 12.

[0062] The deflection portions 112 join the pass-through portions 111. The deflection portions 112 extend substantially parallel to the collimation direction 01. The deflection portions 112 form peripheral walls to the pass-through portions 111. The deflection portions 112 extend around and between two pass-through portions. They form the contours of the pass-through portions 111 and thus participate in defining their shape.

[0063] The deflection portions 1 12 are configured to reflect and / or diffuse the light rays that reach them. For example, they may preferably have a roughness index greater than 100 pm, in order to be able to diffuse and / or reflect incident light rays. Preferably, the deflection portions 1 12 have a roughness greater than that of the passing portions 1 1 1.

[0064] Since the collimated light rays arrive parallel to the deflection portions 1 12, they do not encounter the deflection portions 1 12. On the contrary, since the direct RL2 light rays are not collimated, they propagate in directions which allow them to reach the deflection portions 1 12. The direct RL2 light rays which reach the deflection portions 1 12 are then reflected and / or scattered by the deflection portions 1 12. Thus, a majority of the direct RL2 light rays are sent back out of the exit face 12 by the deflection portions 1 12.

[0065] However, it remains possible that some direct light rays RL2 reaching the deflection parts 112 still reach the exit face 12 of the optical element 1. The quantity of direct light rays RL2 reaching the deflection parts 112 and which still reach the exit face 12 is quite small. The light beam transmitted by the optical element 1 comprises at most 30%, preferably at most 10%, of light rays transmitted by the deflection parts 112. In other words, among the light rays which reach the exit face 12 of the optical element 1, less than 30%, or even less than 10% have been transmitted by the deflection parts 112. This means that the majority of the light rays which form the light beam come from the passing parts 111, and therefore from the collimated light rays RL1.

[0066] In addition, the direct light rays RL2 reaching the deflection parts 1 12 and still reaching the exit face 12 of the optical element 1 are still diffused by the deflection parts 1 12, which allows them to be distributed along the exit face 12. They therefore do not form hot spots on the exit face 12 of the optical element 1 or in the light beam.

[0067] It is also possible that some light rays RL emitted by the light source 21 and not collimated reach the passing parts 1 11. However, when they reach the exit face 12 of the optical element 1, they are hidden by the collimated light rays RL1 which have also entered the optical element via the passing parts 1 11. Thus, these direct light rays 21 transmitted by the passing parts 11 1 do not harm the homogeneity of illumination of the exit face 12 and of the light beam formed.

[0068] The direct light rays RL2 which reach the exit face 12, either by passing through the passing parts 1 1 1 , or by passing through the deflection parts 1 12, form a residual part of all the direct light rays RL2. Less than 50%, preferably less than 30%, even more preferably less than 10% of the direct light rays reach the exit face 12. The light rays transmitted by the optical element therefore correspond mainly to the light rays which have been collimated by the collimation optics 22.

[0069] In order to reduce the chances of transmission of the direct light rays RL2 through the deflection portions 1 12 towards the exit face 12 of the optical element 1, the geometry of the deflection portions 1 12 may be more or less complex. Thus, in a first exemplary embodiment illustrated in FIG. 4, the deflection portions 1 12 are planar. They may for example comprise microstructures, not visible in the figure. Thus, the orientation of the deflection portions 1 12 with respect to the indirect light rays RL2 reaching said deflection portions 1 12 and / or the microstructures makes it possible to generate a reflection and / or a diffusion of these direct light rays.

[0070] According to a second exemplary embodiment illustrated in FIG. 5, the deflection parts 1 12 have an irregular surface condition. In particular, the parts of deflection 1 12 comprise a periodic surface state in a direction transverse to the collimation direction 01.

[0071] In the illustrated example, each deflection portion 112 comprises a plurality of grooves 114 extending rectilinearly along the collimation direction 01. The grooves 114 are arranged side by side. They extend between two passing portions 111. The grooves 114 have a semi-circular transverse profile. It is understood that the grooves 114 could have another transverse profile such as for example a circular, triangular, trapezoidal or sinusoidal transverse profile.

[0072] A transverse dimension of the grooves 1 14 is between 0.1 mm and 1 mm. Preferably, the transverse dimension of the grooves 1 14 is equal to 0.2 mm.

[0073] The grooves 114 make it possible to reflect and / or diffuse the direct RL2 light rays which reach them, and thus to minimize the number of direct RL2 light rays likely to reach the exit face 12.

Claims

Claims

1. Motor vehicle lighting system (2) intended to emit a light beam, comprising: - at least one light source (21) configured to emit light rays (RL); - a collimation optic (22) configured to collimate the light rays (RL) emitted by the at least one light source (21) according to a collimation direction (01); - a transparent optical element (1) comprising an entry face (11) and an exit face (12), arranged opposite the entry face (11), the optical element (1) being intended to transmit said light beam, the entry face (11) comprising: • passing parts (111) each extending in an extension plane, the extension planes being parallel, extending perpendicular to the collimation direction, and being offset from each other according to the collimation direction, said passing parts being configured to transmit the collimated light rays (RL1) towards the exit face (12); and • deflection parts (112) joining the passing parts, and extending substantially parallel to the collimation direction, the deflection parts being configured to reflect and / or diffuse a majority of the light rays emitted by the light source (21) and not collimated by the collimation optics (22), so that said majority of the light rays emitted by the light source (21) and not collimated are returned out of the exit face (12).

2. Lighting system according to the preceding claim, in which the light beam transmitted by the optical element (1) comprises at most 30%, preferably at most 10%, of light rays transmitted by the deflection parts (112).

3. Lighting system according to one of the preceding claims, in which the collimating optics (22) comprises a reflector parabolic, the light source (21) being arranged at the focus of the parabolic reflector.

4. Lighting system according to one of the preceding claims, in which the passing parts have a polygonal shape.

5. Lighting system according to one of the preceding claims, in which the passing parts (111) are smooth, preferably, the passing parts have a roughness index of less than 1 pm.

6. A lighting system according to one of the preceding claims, wherein the deflection portions (112) have a roughness greater than that of the passing portions (111).

7. A lighting system according to any preceding claim, wherein the deflection portions have an irregular surface condition.

8. A lighting system according to any preceding claim, wherein each deflection portion (112) comprises at least one groove (114) which extends rectilinearly along the collimation direction.

9. A lighting system according to the preceding claim, wherein each deflection portion (112) comprises a plurality of grooves (114).

10. A lighting system according to one of the preceding claims, wherein the light beam emitted by the optical element is a signaling beam, such as a position light, a daytime running light or a direction indicator light.

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