Motor vehicle lighting system

Abstract

The invention relates to a lighting system for a motor vehicle, comprising: - a light source (21); - a collimating optical unit (22) collimating light rays (RL) emitted by the light source (21) along a collimating direction (01); - a transparent optical element (1) comprising an entrance face (11) comprising: - transmissive portions (111) extending in parallel extension planes perpendicular to the collimating direction and offset from each other in the collimating direction, wherein the transmissive portions transmit collimated light rays (RL1) towards an exit face (12); and - deflection portions (112) adjoining the transmissive portions and extending substantially parallel to the collimating direction, wherein the deflection portions reflect or scatter a substantial portion of direct light rays such that a substantial portion of the direct light rays does not reach the exit face (12).

Description

[0001] The technical background of this invention is the technical background of motor vehicle lighting systems. In particular, this invention falls within the background of lighting and / or signaling devices for motor vehicles.

[0002] Prior art discloses light-emitting systems, particularly lighting and / or signaling systems, which include: - LED (Light Emitting Diode) light source; - A reflector used to collimate light rays produced by a light source; and - An optical element through which collimated light rays are transmitted to the outside.

[0003] In such known lighting and / or signaling systems, the reflector is, for example, a parabolic reflector, and the light source is arranged at the focal point of the reflector. Therefore, the reflector collimates the light emitted by the light source. The collimated light is then shaped and transmitted by optical elements to produce a beam of light that can, for example, aid in signaling functions.

[0004] A known drawback of such lighting and / or signaling systems is that some of the light emitted by the light source is not collected by the reflector. Specifically, some of the light emitted by the light source is emitted directly along the direction of the optical element. These rays (called direct rays) are not collimated and therefore create illumination inhomogeneities at the optical element, particularly at its exit surface. In other words, these direct rays produce parasitic hot spots, also known as high-intensity spots, in the resulting beam and on the exit surface of the optical element. The appearance of the beam and the exit surface of the optical element are thus unsatisfactory because they are not uniform enough.

[0005] To limit the occurrence of such hot spots on optical elements, it is known to position a shield between the light source and the optical element. This shield thus allows for the cutting off of light emitted by the light source and directly along the direction of the optical element. However, by cutting off these direct rays, the shield then creates dark areas on the optical element and in the resulting beam. Specifically, the shield creates shadows on the optical element, particularly on its exit surface. These dark areas on the optical element degrade the illuminated appearance of the optical element, especially its exit surface. Furthermore, the beam transmitted through the optical element still appears insufficiently uniform.

[0006] One object of the present invention is to provide a vehicle lighting system that solves at least most of the above-mentioned problems and provides other advantages.

[0007] In particular, an object of the present invention is to provide a light-emitting system that enables improvement in the illuminated appearance of the exit surface of an optical element, especially its uniformity, as well as improvement in the uniformity of the light beam transmitted by the optical element.

[0008] Another object of the present invention is to provide a light-emitting system wherein hot spots or shadow areas are limited on the emitting surface of such optical element and in the transmitted beam.

[0009] According to a first aspect of the present invention, a vehicle light-emitting system for emitting a light beam is provided, the vehicle light-emitting system comprising: - At least one light source, which is configured to emit light; - A collimating optical unit configured to collimate light emitted by at least one light source along a collimating direction; - A transparent optical element comprising an incident surface and an exit surface arranged opposite to the incident surface, the optical element being designed to transmit the light beam, the incident surface comprising: • Transmitting portions, each extending in parallel, collimating planes, and offset from each other in the collimating direction, the transmitting portions being configured to transmit collimated light rays to the exit surface; and • Deflection portions, which are adjacent to the transmission portions and extend substantially parallel to the collimation direction, are configured to reflect and / or scatter most of the light rays emitted by the light source and not collimated by the collimating optical unit, such that most of the light rays emitted by the light source and not collimated are returned outside the exit surface.

[0010] In the context of this invention, optical elements are configured such that certain light rays can be transmitted between their incident and exit surfaces. The optical elements are particularly transparent to light used in the automotive field, that is, transparent to light rays having wavelengths contained within the visible spectrum, specifically wavelengths between 400 nm and 700 nm.

[0011] In the context of this invention, an optical element is configured to guide incident light rays passing through an incident surface, and particularly a transmission portion, in a predetermined direction to form a light beam outside an exit surface. In a first example, the optical element may be a lens. In this first example, the propagation direction of the light rays outside the exit surface is different from the propagation direction of the light rays reaching the incident surface. Alternatively, the optical element may be an optically neutral element for incident light rays passing through the transmission portion in the direction along the exit surface. In the case where the optical element is optically neutral, the propagation direction of the light rays outside the exit surface is exactly the same as the propagation direction of the light rays reaching the incident surface.

[0012] In the context of this invention, the exit surface is located downstream of the incident surface relative to the direction of light propagation through the optical element, particularly relative to the collimation direction.

[0013] In the context of this invention, the transmission portion is configured to transmit incident light rays propagating perpendicularly to or substantially perpendicularly to its extending plane. In this invention, these incident light rays propagating perpendicularly to or substantially perpendicularly to its extending plane correspond to light rays propagating parallel to or substantially parallel to the collimation direction, and therefore correspond to light rays that have been collimated by the collimating optical unit. It should be understood that if a light ray has an angle of less than or equal to 10° or 20° relative to the collimation direction, then the light ray extends parallel to or substantially parallel to the collimation direction. In the context of this invention, light rays incident on one of the transmission portions are transmitted or refracted by said transmission portion and propagate through the optical element along the direction of the exit surface.

[0014] In the context of this invention, it should be understood that the transmission portions are non-intersecting and far apart from each other. In particular, the transmission portions form surfaces that are stepped relative to each other. The deflection portions extend between two directly adjacent transmission portions.

[0015] The deflecting portion forms the wall around the outer periphery of the transmitting portion. Specifically, the deflecting portion surrounds the two transmitting portions and extends between them. In other words, the deflecting portion forms the outline of the transmitting portion.

[0016] In the context of this invention, light rays emitted by the light source and collimated by the collimating optical unit return parallel to the collimation direction. Therefore, the light rays collimated by the collimating optical unit are parallel to each other and parallel to the collimation direction.

[0017] In the context of this invention, light emitted by a light source but not collimated by a collimating optical unit is also referred to as "direct light".

[0018] In the context of this invention, "light rays returning outside the exit surface" means that these light rays do not reach the exit surface of the optical element. For example, light rays can be reflected or scattered by the incident surface of the optical element, preventing them from reaching the exit surface.

[0019] The statement that most of the light rays emitted by the light source but not collimated return to the exit surface should be understood as less than 50%, preferably less than 30%, or even more preferably less than 10% of the direct light rays return to the exit surface; in other words, less than 50%, preferably less than 30%, or even more preferably less than 10% of the direct light rays reach the exit surface of the optical element.

[0020] With this invention, the light transmitted by the optical element primarily corresponds to the light already collimated by the collimating optical unit. Specifically, direct light rays that are not collimated by the collimating optical unit and directly reach the incident surface of the optical element will be primarily reflected or scattered by the deflecting portions beyond the exit surface of the optical element. Conversely, light rays collimated by the collimating optical unit will only encounter the transmission portions. Specifically, since the deflecting portions extend parallel to the collimation direction, they do not intercept collimated light rays. Therefore, all collimated light rays enter the optical element through the transmission portions and are thus transmitted by the optical element to the exit surface.

[0021] Therefore, the light beam transmitted by the optical element is mainly formed by rays already collimated by the collimating optical unit. In this case, direct rays constitute only a small minority of the rays forming the beam. Furthermore, the small number of direct rays reaching the exit surface of the optical element and thus forming the beam are scattered by the deflection portion of the incident surface, particularly the incident surface of the optical element. The direct rays are therefore distributed along the exit surface. Thus, they no longer form hot spots on the exit surface of the optical element or in the beam.

[0022] Furthermore, since the optical elements are transparent, no dark areas are formed on the exit surface of the optical elements or in the beam.

[0023] Therefore, by using an incident surface structure that includes both a transmission section and a deflection section, a uniformly illuminated exit surface and a uniform beam can be obtained. This solution also has the advantage of requiring no additional components. The optical elements alone ensure that the illumination of the exit surface is uniform and the beam is uniform.

[0024] A light-emitting system may include one or more of the following features.

[0025] According to an alternative embodiment of the invention, the collimation direction corresponds to the direction of the optical axis of the light-emitting system. This collimation direction may also be referred to as the longitudinal direction.

[0026] According to an alternative embodiment of the invention, the light beam transmitted by the optical element comprises at most 30%, preferably at most 10%, of the light transmitted by the deflection portion. Since the deflection portion extends substantially parallel to the collimation direction, only direct light rays can reach the deflection portion. Therefore, the statement "the light beam transmitted by the optical element comprises at most 30%, preferably at most 10%, of the light transmitted by the deflection portion" means that the direct light rays transmitted by the optical element account for only 30%, and correspondingly 10%, of the light rays forming the light beam. Therefore, it should be understood that hot spots in the beam and on the exit surface are avoided.

[0027] According to an alternative of the invention, the light beam transmitted by the optical element includes at most 1% of the light transmitted by the deflection portion. Therefore, almost no direct light reaches the exit surface and is transmitted by the optical element.

[0028] According to an alternative embodiment of the invention, no direct rays reach the exit surface. In other words, the optical element only allows collimated rays to pass through. In this case, the beam is formed entirely by collimated rays. The uniformity of illumination at the exit surface and the uniformity of the beam are further improved.

[0029] According to an alternative embodiment of the invention, the collimating optical unit includes a reflector. Advantageously, the collimating optical unit includes a parabolic reflector, and the light source is arranged at the focal point of the parabolic reflector. Therefore, the parabolic reflector makes it possible to collimate the light emitted by the light source.

[0030] According to an alternative embodiment of the invention, the transmissive portion has a polygonal shape. Preferably, the transmissive portion has a quadrilateral or hexagonal shape. These shapes allow for minimizing the gap between two adjacent transmissive portions.

[0031] According to an alternative of the invention, all the transmitting portions have exactly the same shape. "Exactly the same shape" should be understood to mean that all the shapes of the transmitting portions have the same geometry and the same dimensions. Alternatively, the transmitting portions may have different shapes. Alternatively, the transmitting portions may all have the same shape but different dimensions, depending on their position along the incident surface of the optical element.

[0032] According to an alternative embodiment of the invention, the transmissive portion is smooth. Preferably, the transmissive portion has a roughness index of less than 1 µm. The transmissive portion may also be polished. This configuration facilitates the transmission of light through the transmissive portion.

[0033] According to an alternative embodiment of the invention, the deflecting portion has a roughness index greater than 100 µm. The roughness of the deflecting portion facilitates the scattering and / or reflection of light incident on it.

[0034] According to an alternative of the invention, the roughness of the deflection portion is greater than the roughness of the transmission portion.

[0035] According to an alternative embodiment of the invention, the deflecting portion has an irregular surface condition. Irregularity should be understood to mean that the overall structure of the deflecting portion is variable depending on its position on the outer peripheral wall. For example, the morphology of the deflecting portion is random.

[0036] According to an alternative embodiment of the invention, each deflection portion has a periodic surface condition in at least one direction of the deflection portion. Periodicity should be understood as meaning that the surface condition of a given deflection portion comprises a repeating pattern along the deflection portion. This advantageous configuration facilitates the scattering or reflection of light incident on the deflection portions.

[0037] According to an alternative embodiment of the invention, each deflection portion includes at least one groove extending linearly along the collimation direction. For example, each at least one groove extends between the first transmission portion and the second transmission portion.

[0038] In the context of this invention, a groove should be understood as a channel or rib extending linearly along one of the deflection portions, and the groove can take any shape. In particular, at least one groove may have a circular or semi-circular or triangular or sinusoidal or trapezoidal lateral profile. For example, the lateral 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 embodiment of the invention, each deflection portion includes a plurality of grooves. In particular, the grooves may be arranged side by side and each extends linearly along the collimation direction.

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

[0041] On the one hand, other features and advantages of the invention will become clearer from the following description, and on the other hand, from the numerous non-limiting exemplary embodiments given in an indicative manner with reference to the accompanying illustrative drawings, in which: [ Figure 1 ] Figure 1 A light-emitting system according to the invention is integrated into a partially depicted light-emitting device of a motor vehicle; [ Figure 2 ] Figure 2 A schematic cross-sectional view of the light-emitting system according to the present invention is shown; [ Figure 3 ] Figure 3 Showing Figure 2 Detailed view of the light-emitting system shown; [ Figure 4 ] Figure 4 Showing Figures 1 to 3 A first exemplary embodiment of the incident surface of the optical element equipped with the light-emitting system shown; [ Figure 5 ] Figure 5 Showing Figures 1 to 3 A second exemplary embodiment of the incident surface of the optical element equipped with the light-emitting system shown.

[0042] Of course, the features, variations, and various embodiments of the present invention can be combined with each other in various combinations, as long as they are compatible or non-exclusive. In particular, they can be combined with each other if there is nothing from a technical point of view that prevents the combination of all the described variations and all embodiments.

[0043] In the accompanying drawings, elements common to several drawings retain the same reference numerals.

[0044] Figure 1 A partial three-dimensional view shows a motor vehicle light-emitting device 3, and more specifically, a lighting and / or signaling device for a motor vehicle. The light-emitting device 3 can be, in particular, a motor vehicle headlight or taillight. The light-emitting device 3 includes, in particular, a light-emitting system 2 according to the invention at its periphery. The light-emitting device 3 includes other light-emitting elements 4 at its periphery. In this example, the light-emitting system 2, like the other light-emitting elements 4, contributes to performing signaling functions, such as position light functions, daytime running light functions, or turn signal functions.

[0045] Figure 2 and Figure 3 The light-emitting system 2 according to the present invention is shown in more detail. In particular, Figure 2 A schematic cross-sectional view of the light-emitting system 2 is shown, and Figure 3 The details of the light-emitting system 2 are schematically shown. The light-emitting system 2 includes: a light source 21 configured to emit light rays RL; a collimating optical unit 22 configured to collimate some of the light rays RL emitted by at least one light source 21 along a collimating direction O1; and an optical element 1 designed to transmit the light rays emitted by the light source 21 to form a light beam. The optical element 1 is configured to guide the incident light rays in a predetermined direction to form a light beam.

[0046] The light source 21 is preferably a light-emitting diode (LED). In the example shown, the light-emitting system 2 includes a single light source 21. It goes without saying that the light-emitting system 2 may include multiple light sources without departing from the scope of the invention. The arrangement and / or orientation of the light source 21 in the light-emitting system 2 results in some of the light rays RL1 emitted by the light source 21 reaching the collimating optical unit 22, while other light rays RL2 emitted by the light source 21 reach the optical element 1 directly without passing through the collimating optical unit 22. These light rays RL2 then reach the optical element 1 in various directions.

[0047] The light RL1 emitted by the light source 21 and reaching the collimating optical unit 22 is called an indirect ray. The light RL2 emitted by the light source 21 and reaching the optical element 1 directly without passing through the collimating optical unit 22 is called a direct ray.

[0048] The collimating optical unit 22 is configured to collimate the light rays RL emitted by at least one light source 21 and arriving thereto. Therefore, all light rays RL1 emitted by at least one light source 21 and arriving at the collimating optical unit 22 are returned parallel to each other and parallel to the collimation direction O1. The collimation direction O1 may specifically correspond to the direction of the optical axis of the light-emitting system 2. In this invention, the collimation direction O1 corresponds to the longitudinal direction. These light rays RL1 then reach the optical element 1 along the collimation direction O1.

[0049] In the example shown, the collimating optical unit 22 includes a parabolic reflector, and the light source 21 is arranged at the focal point of the parabolic reflector. Therefore, the indirect ray RL2 returns to the optical element 1 parallel to the collimating direction O1 after being reflected from the parabolic reflector.

[0050] Optical element 1 includes an incident surface 11 and an exit surface 12 arranged opposite to the incident surface 11. The incident surface 11 faces the collimating optical unit 22. The exit surface 12 is located downstream of the incident surface 11 with respect to the direction of light propagation through the optical element 1, especially with respect to the collimating direction O1.

[0051] The incident surface 11 of optical element 1 includes Figure 3 The transmission portion 111 and the deflection portion 112 are particularly visible in the middle.

[0052] As will be described below, optical element 1 is configured to process direct ray RL2 in a manner different from that of indirect ray RL1. In particular, optical element 1 is configured to facilitate the transmission of indirect ray RL1 to the exit surface and to prevent direct ray RL2 from being transmitted to the exit surface 12 as much as possible. The transmission portion 111 and the deflection portion 112 make this separate processing of indirect ray RL1 and direct ray RL2 possible.

[0053] Each of the transmission portions 111 extends in an extension plane. The extension planes of the transmission portions 111 are parallel and extend perpendicular to the collimation direction. Furthermore, the extension planes of the transmission portions 111 are offset from each other in the collimation direction O1. Therefore, the transmission portions 111 do not intersect and are far apart from each other. The transmission portions 111 form a stepped surface relative to each other.

[0054] In the examples shown, and as in Figure 4 and Figure 5 As is particularly evident, all the transmissive portions 111 have the same shape, namely, they are all square. It goes without saying that the invention is not limited to this particular shape, and that the transmissive portions 111 may take another shape, such as any other polygonal shape, or more specifically, a quadrilateral or hexagonal shape, without departing from the scope of the invention. The transmissive portions 111 may also have different shapes or different sizes.

[0055] The transmissive portions 111 are smooth. They preferably have a roughness index of less than 1 µm. They may also be polished.

[0056] The transmission section 111 allows light rays RL1 emitted by the light source 21 and collimated by the collimating optical unit 22 to be transmitted to the optical element 1. Specifically, since the collimated light rays RL1 arrive perpendicular to the extension plane of the transmission section 111, they pass through the transmission section 111 and are transmitted into the optical element 1 without being deflected. These light rays then propagate through the optical element 1 to the exit surface 12.

[0057] The deflecting portion 112 is adjacent to the transmitting portion 111. The deflecting portion 112 extends substantially parallel to the collimation direction O1. The deflecting portion 112 forms a wall around the outer periphery of the transmitting portion 111. The deflecting portions 112 surround the two transmitting portions and extend between the two transmitting portions. They form the outline of the transmitting portion 111 and thus help define its shape.

[0058] The deflecting portions 112 are configured to reflect and / or scatter light arriving at them. For example, they may preferably have a roughness index greater than 100 µm in order to be able to scatter and / or reflect incident light. Preferably, the roughness of the deflecting portions 112 is greater than the roughness of the transmission portions 111.

[0059] Since the collimated rays arrive parallel to the deflection section 112, they do not encounter the deflection section 112. Conversely, since the direct rays RL2 are not collimated, they propagate in the direction that allows them to reach the deflection section 112. The direct rays RL2 that reach the deflection section 112 are then reflected and / or scattered by the deflection section 112. Therefore, most of the direct rays RL2 return to the outside of the exit surface 12 through the deflection section 112.

[0060] However, some of the direct rays RL2 reaching the deflection section 112 may still reach the exit surface 12 of the optical element 1. The amount of direct rays RL2 that reach the deflection section 112 and still reach the exit surface 12 is relatively small. The light beam transmitted by the optical element 1 includes at most 30%, preferably at most 10%, of the rays transmitted by the deflection section 112. In other words, less than 30%, or even less than 10%, of the rays reaching the exit surface 12 of the optical element 1 has been transmitted by the deflection section 112. This means that most of the light forming the light beam comes from the transmission section 111, and therefore from the collimated rays RL1.

[0061] Furthermore, the direct rays RL2 that reach the deflection section 112 and still reach the exit surface 12 of the optical element 1 are still scattered by the deflection section 112, thus allowing them to be distributed along the exit surface 12. Therefore, they will not form hot spots on the exit surface 12 of the optical element 1 or in the beam.

[0062] Some rays RL emitted by the light source 21 but not collimated may also reach the transmission section 111. However, when they reach the exit surface 12 of the optical element 1, they are blocked by the collimated rays RL1 that have also entered the optical element through the transmission section 111. Therefore, these direct rays 21 transmitted by the transmission section 111 do not adversely affect the illumination of the exit surface 12 and the uniformity of the formed beam.

[0063] The residual portion of the set of direct rays RL2 is formed by the direct rays RL2 that pass through the transmission portion 111 or the deflection portion 112 to reach the exit surface 12. Less than 50%, preferably less than 30%, and even more preferably less than 10% of the direct rays reach the exit surface 12. Therefore, the light transmitted by the optical element mainly corresponds to the light that has been collimated by the collimating optical unit 22.

[0064] To reduce the chance of direct light RL2 being transmitted through the deflection portion 112 along the direction of the exit surface 12 of the optical element 1, the geometry of the deflection portion 112 may be more or less complex. Therefore, in Figure 4 In the first exemplary embodiment shown, the deflection portions 112 are planar. They may include, for example, microstructures not visible in the figures. The orientation and / or microstructure of the deflection portions 112 relative to the indirect light rays RL2 reaching the deflection portions 112 thus make it possible to produce reflection and / or scattering of these direct light rays.

[0065] according to Figure 5 In the second exemplary embodiment shown, the deflection portion 112 has an irregular surface condition. In particular, the deflection portion 112 includes a periodic surface condition in the direction transverse to the collimation direction O1.

[0066] In the example shown, each deflection portion 112 includes a plurality of grooves 114 extending linearly along the collimation direction O1. The grooves 114 are arranged side by side. They extend between two transmission portions 111. The grooves 114 have a semi-circular lateral profile. Needless to say, the grooves 114 may have another lateral profile, such as a circular, triangular, trapezoidal, or sinusoidal lateral profile.

[0067] The lateral dimension of the groove 114 is between 0.1 mm and 1 mm. Preferably, the lateral dimension of the groove 114 is equal to 0.2 mm.

[0068] The groove 114 allows direct rays RL2 that can be reflected and / or scattered to them, and thus minimizes the number of direct rays RL2 that may reach the exit surface 12.

Claims

1. A motor vehicle light emission system (2) designed to emit a light beam, comprising: - At least one light source (21), said at least one light source being configured to emit light rays (RL); - Collimating optical unit (22), the collimating optical unit being configured to collimate the light rays (RL) emitted by the at least one light source (21) along the collimating direction (O1); - A transparent optical element (1), the transparent optical element comprising an incident surface (11) and an exit surface (12) arranged opposite to the incident surface (11), the optical element (1) being designed to transmit a light beam, the incident surface (11) comprising: • Transmitting portions (111), each extending in an extension plane that is parallel, extends perpendicular to the collimation direction, and is offset from each other in the collimation direction, the transmitting portions being configured to transmit the collimated ray (RL1) to the exit surface (12). as well as • Deflection portion (112), which is adjacent to the transmission portion and extends substantially parallel to the collimation direction, is configured to reflect and / or scatter most of the light rays emitted by the light source (21) and not collimated by the collimating optical unit (22), such that most of the light rays emitted by the light source (21) and not collimated are returned outside the exit surface (12).

2. The light-emitting system as described in the preceding claim, wherein, The light beam transmitted by the optical element (1) includes up to 30%, preferably up to 10%, of the light transmitted by the deflection portion (112).

3. The light-emitting system as described in any of the preceding claims, wherein, The collimating optical unit (22) includes a parabolic reflector, and the light source (21) is arranged at the focal point of the parabolic reflector.

4. The light-emitting system as described in any one of the preceding claims, wherein, The transmissive portion has a polygonal shape.

5. The light-emitting system as described in any one of the preceding claims, wherein, The transmissive portion (111) is smooth, and preferably, the transmissive portion has a roughness index of less than 1 µm.

6. The light-emitting system as described in any one of the preceding claims, wherein, The roughness of the deflection portion (112) is greater than the roughness of the transmission portion (111).

7. The light-emitting system as described in any of the preceding claims, wherein, The deflection portion has an irregular surface condition.

8. The light-emitting system as described in any of the preceding claims, wherein, Each deflection portion (112) includes at least one groove (114) extending in a straight line along the collimation direction.

9. The light-emitting system as claimed in the preceding claim, wherein, Each deflection portion (112) includes multiple grooves (114).

10. The light-emitting system as described in any one of the preceding claims, wherein, The light beam emitted by the optical element is a signal beam, such as a position light, daytime running light, or turn signal.

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