Light module comprising a plastics housing provided with a part for protecting the plastics housing against the effect of focused light rays

Abstract

The invention relates to a light module (2) integrated in the front or rear end of a vehicle, the light module (2) comprising a plastics housing (4) defining a recess (6) in which the following are arranged: at least one light source (7) and an optical imaging system, the plastics housing (4) comprising a bottom (3A). According to the invention, the plastics housing (4) is provided with a part (10) extending vertically on the bottom (3A) thereof, the part (10) being arranged on the bottom (3A) so that its location on the bottom (3A) corresponds to an area located at or in front of an area for focusing light rays coming from the sun and focused by the optical imaging system, and being configured so as to block the focused light rays coming from the sun while allowing the passage of the light rays coming from the at least one light source (7) and propagating towards the optical imaging system.

Description

Light module comprising a plastic housing with a part protecting the plastic housing against the effect of focused light rays

[0001] The present invention belongs to the field of lighting, in particular lighting for motor vehicles. The invention relates in particular to a light module for a vehicle comprising a plastic housing and an optical imaging system. The optical imaging system is typically a direct optical imaging system and comprises, for example, one or more projection lenses. Without this being limiting within the scope of the present invention, the light module may be mounted in a lighting or signaling element and / or in a motor vehicle headlight. State of the art

[0002] Current vehicle headlamps generally include a projection lens-type optical imaging system, which is responsible for projecting the light emitted by the internal light sources to illuminate the road ahead of the vehicle. Such a projection lens is generally fixed within a housing provided with an opening for the passage of the light projected by the projection lens, which housing is itself protected by another translucent or partially translucent optical system of the external lens type.

[0003] However, with the increase in plastic parts inside the projector, a problem arises when the sun's rays hit the projection lens (at certain particular angles of incidence) and the radiation is focused on one or more points inside the projector. Previously, the material on which this or these focusing points were located was a metallic material. The heat then dissipated quickly and easily, so that no damage was done to this part of the projector. However, if the material on which this or these focusing points are located is a plastic material, as is the case in current vehicle projectors, the heat does not dissipate as easily, and damage and deformation can occur at this or these points, with potentially serious consequences for the sealing and operation of the projector.This known thermal phenomenon, generated by a magnifying effect at the projection lens and called "sunburn" in English, thus creates hot spots on the relevant plastic part of the projector, such hot spots being capable of seriously damaging the part. Such a phenomenon of the appearance of dangerous hot spots can also be created if indirect light beams from light-emitting diodes of the module are deflected by the projection lens in the same way as explained above, in such a case, this phenomenon is called "LEDburn" in English.

[0004] To address this problem, some manufacturers place an additional metal part at the intended location for focusing the sun's rays, and others try to absorb the radiant energy so that the radiation is not too harmful. For example, US patent document 2013 / 0223090 A1 describes a light module integrated into the front or rear of a vehicle. The light module comprises a lens support part, the support part being hollow and made of a plastic material. The inner side walls of the plastic support part are coated with a protective metal element, which is, for example, overmolded. The plastic support part then forms a hybrid component, integrating this metal surface element, which covers its inner side walls, from the moment it is manufactured (the plastic part is in fact formed via injection molding directly onto the metal surface element).

[0005] However, a disadvantage of the light module described in this patent document US 2013 / 0223090 A1 is that it is complex and expensive to produce, due to the particular manufacturing process of the hybrid support part. In addition, due to such a protective metal coating on the inner side walls of the plastic support part, stray reflections of light may occur from the light sources to the outside of the light module.

[0006] Patent document DE 102013214990 A1 describes a light module comprising a lens holder made entirely or partially of plastic and which is provided with a metallic coating in order to prevent damage from the sun or deformation of the lens holder. A disadvantage of such a light module is that it is also complex and expensive to produce.

[0007] The present invention improves the situation.

[0008] An objective of the invention is to propose a light module integrated into the front or rear face of a vehicle and comprising an optical imaging system (of the projection lens or reflector type) and a plastic housing inside which the optical imaging system is arranged, which makes it possible to effectively protect the plastic housing from the effect of focused light rays, while being less complex and less expensive to produce.

[0009] To this end, a first aspect of the invention relates to a light module integrated into the front or rear face of a vehicle, the light module comprising a plastic casing defining a housing inside which are arranged: at least one light source and an optical imaging system, the optical imaging system being arranged opposite said at least one light source and configured so as to generate a light beam, the plastic casing comprising a bottom.

[0010] According to the invention, the plastic housing is provided with a part extending vertically on its bottom, in the housing, said part being arranged between said at least one light source and the optical imaging system, and being arranged on the bottom of the plastic housing in such a way that its location on the bottom corresponds to an area located at or in front of a focusing area of ​​light rays coming from the sun and focused by the optical imaging system, said part being configured so as to block the focused light rays coming from the sun while allowing the light rays coming from said at least one light source and propagating towards the optical imaging system to pass.

[0011] Such a part thus configured and judiciously positioned on the bottom of the plastic housing ensures a function of protecting the plastic housing against the undesirable effects of focused light rays from the sun. Indeed, the part makes it possible to cut the focused light rays from the sun in an area located upstream of a focusing point of these light rays, and thus to avoid any phenomenon of localized overheating on the plastic housing. The light module according to the present invention thus provides an effective, lightweight and inexpensive means to produce to ensure the function of protecting the plastic housing against focused light radiation from the sun. In addition, the presence on the bottom of the housing of such a part thus configured advantageously makes it possible to stiffen the light module, because the part forms a sort of stiffening rib for the module.

[0012] According to a first embodiment, said part is attached to the bottom of the plastic case.

[0013] According to a second embodiment, said part is made in one piece with the plastic housing, in particular via injection molding.

[0014] According to an embodiment of the first or second variant, said part is made of a plastic or metallic material. When the part is made of a plastic material, it makes it possible to avoid parasitic reflections in the direction of propagation of the light source towards the outside of the module, because no metal part is used to ensure the function of protecting the plastic housing. In addition, the use of a plastic material for the part makes it possible to reduce the risks of excessive heating of the latter. The material is typically a material chosen to resist the phenomenon of irradiance of the light rays striking the part.

[0015] According to one embodiment of the invention, said part has a cutout arranged opposite said at least one light source to allow the light rays coming from said at least one light source to pass through and propagating towards the optical imaging system.

[0016] According to a preferred embodiment of the invention, said part has at least one protuberance projecting towards the optical imaging system and arranged on the bottom of the plastic housing such that its location on the bottom corresponds to an area located at or in front of a focusing area of ​​light rays coming from the sun and focused by the optical imaging system, said at least one protuberance having a shape such that it blocks the focused light rays coming from the sun upstream of a focusing point of these light rays.Such a protuberance thus configured advantageously makes it possible to cut the focused light rays coming from the sun as far forward as possible to avoid a concentration forming hot spots on the plastic part, while avoiding blocking the light rays coming from the at least one light source and propagating towards the optical imaging system to ensure the lighting function.

[0017] According to one embodiment of the invention, said at least one protuberance has a truncated or pointed shape. Such a shape advantageously makes it possible to reduce the concentration of focused light rays from the sun.

[0018] According to one embodiment of the invention, the optical imaging system is a direct optical imaging system.

[0019] According to one embodiment of the invention, said direct optical imaging system comprises one or more projection lenses.

[0020] Another subject of the invention relates to a lighting and / or signaling element for a vehicle, in particular a motor vehicle, comprising a light module according to the invention.

[0021] Here, "vehicle" means any type of vehicle such as a motor vehicle, a moped, a motorcycle, a storage robot in a warehouse, or any other machine capable of carrying at least one passenger or intended for the transport of people or objects.

[0022] Another subject of the invention relates to a vehicle headlight comprising a light module or a lighting and / or signaling element according to the invention.

[0023] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings in which:

[0024] is a perspective view of a light module according to one embodiment of the invention, the light module comprising a cover and an optical imaging system;

[0025] is a perspective view from above of the light module of the, in which the cover and the optical imaging system have been omitted;

[0026] is a perspective view of the light module of the, in which the cover and the optical imaging system have been omitted;

[0027] is another perspective view of the light module of the, in which the cover and the optical imaging system have been omitted, the light module further comprising a collecting lens; and

[0028] is a view similar to that of the, in which the collecting lens has been omitted.

[0029] In this document, unless otherwise indicated, the terms "horizontal", "vertical" or "transverse", "lower", "upper", "above", "below", "top", "bottom", "side" are defined in relation to the orientation of the light module 2 according to the invention, intended to be mounted in a vehicle lighting and / or signaling element. In particular, in this application, the term "vertical" designates an orientation perpendicular to the horizon while the term "horizontal" designates an orientation parallel to the horizon.

[0030] Furthermore, anything referred to as "rear" or "front" is referred to relatively with reference to the face of the lighting and / or signaling element closest to the exterior of the vehicle. Thus, anything referred to as "rear" is located on the side furthest from the exterior of the vehicle in the latter's main direction of extension, while anything referred to as "front" is located on the side closest to the exterior of the vehicle in the latter's main direction of extension. However, with regard to the vehicle's lights, these are referred to as "front" or "rear" depending on the rear-front direction of the vehicle, and therefore according to the latter's conventional direction of travel. Detailed description

[0031] Figures 1 to 5 show a light module 2 according to one embodiment of the invention. The light module 2 has an optical axis A-A'. The light module 2 is integrated into the front or rear face of a vehicle and is intended to be installed in a lighting and / or signaling element of the vehicle (the lighting and / or signaling element and the vehicle not being shown in the figures). The lighting and / or signaling element may typically be part of a headlight of the vehicle. The light module 2 comprises a plastic housing 4, preferably hermetic. The light module also comprises a heat sink 1, which is for example in the form of a finned radiator.

[0032] The plastic housing 4 is conventionally closed by an optical imaging system 5. The optical imaging system 5 is configured to generate a light beam, and is typically a direct optical imaging system comprising for example one or more projection lenses. In the particular embodiment illustrated in Figures 1 to 5, the plastic housing 4 consists of a bottom 3A and a cover 3B mounted on the bottom 3A. The plastic housing 4 defines a housing 6 inside which are arranged, in addition to the optical imaging system 5, several light sources 7. In the particular embodiment illustrated in Figures 1 to 5, the light module 2 also comprises a collecting lens 8 arranged in the housing 6 in front of the light sources 7, more precisely between the light sources 7 and the optical imaging system 5.The light sources 7 are typically light-emitting diodes, and are oriented in the optical axis A-A' of the light module 2. The optical imaging system 5 is arranged in front of and opposite the light sources 7 and the collecting lens 8. The heat sink 1, which makes it possible to dissipate the heat emitted by the light sources 7, is fixed on a rear face of a printed circuit board 9 (visible on the) on which the light sources 7 are mounted.

[0033] The plastic housing 4 is provided with a part 10 extending vertically on its bottom 3A, in the housing 6. The part 10 is arranged between the light sources 7 and the optical imaging system 5, more precisely between the collecting lens 8 and the optical imaging system 5 in the particular embodiment of FIGS. 1 to 5. The part 10 is arranged on the bottom 3A of the plastic housing 4 in such a way that its location on the bottom 3A corresponds to an area situated at or in front of a focusing area of ​​light rays coming from the sun and focused by the optical imaging system 5.

[0034] The part 10 is configured so as to block the focused light rays coming from the sun while allowing the light rays coming from the light sources 7 and propagating towards the optical imaging system 5 to pass through (the latter rays ensuring the lighting function of the light module 2). More precisely, according to a particular embodiment, the part 10 is provided with a cutout 12 arranged opposite the light sources 7 to allow the light rays coming from the light sources 7 and propagating towards the optical imaging system 5 to pass through. According to this particular exemplary embodiment, the part 10 takes the form of a substantially vertical wall and is formed from a substantially rectangular part blank (not shown in the figures) in which the cutout 12 is formed.The cutout 12 here takes the form of a rectangle of length and width less than the length and width of the part 10, but can take any other form suitable for its function of allowing the light rays coming from the light sources 7 to pass through and propagating towards the optical imaging system 5. The part 10 thus configured advantageously makes it possible to cut the light rays coming from the sun and passing through the optical imaging system 5 (the light rays in fact striking the substantially vertical wall formed by the part 10), in an area located upstream of a focal point of these light rays. The part 10 thus makes it possible to avoid the focusing of the light rays coming from the sun on the inside of the plastic housing 4, and consequently prevents any phenomenon of localized overheating on the housing 4.Furthermore, the propagation of the light rays coming from the light sources 7 and propagating towards the optical imaging system 5 is not hindered by the part 10, the light rays in fact passing through the cutout 12 and striking the optical imaging system 5. It is therefore understood that the part 10 thus configured makes it possible to block the focused light rays coming from the sun while allowing the light rays coming from the light sources 7 and propagating towards the optical imaging system 5 to pass.

[0035] Preferably, the part 10 is made of a plastic material. Alternatively, the part 10 may be made of a metallic material. The material is typically a material chosen to resist the phenomenon of irradiance of light rays striking the part 10. Preferably, the plastic material chosen for the plastic housing 4 and for the part 10 when the latter is made of plastic is polyethylene terephthalate (also called PET) reinforced with glass, preferably with a proportion of approximately 35% glass. Such a material is more robust and has better thermal properties, and is therefore more resistant to light radiation from the sun (it is more resistant in particular to the effects of thermal irradiance), compared to the materials used in the prior art.In the particular embodiment of Figures 1 to 5, the part 10 is integral with the plastic housing 4 (more precisely with the bottom 3A and the internal side walls 3C of the plastic housing 4), in particular via injection molding. In a variant not shown, the part 10 can be attached to the bottom 3A of the plastic housing 4.

[0036] According to a preferred embodiment of the invention, the part 10 has at least one protrusion 14 projecting forwards towards the optical imaging system 5. In the particular embodiment illustrated in Figures 2 to 5, the part 10 comprises two such protrusions 14, each of which projects forwards from the vertical wall of the part 10. Each protrusion 14 is arranged on the bottom 3A of the plastic housing 4 such that its location on the bottom 3A corresponds to an area located at or in front of a focusing area of ​​light rays coming from the sun and focused by the optical imaging system 5. Each protrusion 14 has a shape such that it blocks the focused light rays coming from the sun upstream of a focusing point of these light rays. In the particular embodiment of Figures 2 to 5, each protrusion 14 has a frustoconical or pointed shape.More specifically, according to this particular embodiment, each protuberance 14 has a longitudinal section taken along a vertical section plane parallel to the internal side walls 3C of the housing 4, which is substantially trapezoidal in shape, the bases of the trapezoid being of distinct lengths. In a variant not shown, each protuberance 14 may have a shape such that the longitudinal section of the protuberance 14 taken along the vertical section plane is in the shape of a right triangle, or any other shape suitable for its function of blocking the focused light rays coming from the sun as far forward as possible from a point of focus of these light rays, while avoiding blocking the light rays coming from the light sources 7 and propagating towards the optical imaging system 5.Each protuberance 14 may be integral with the base 3A of the plastic housing 4 (as is the case in the particular embodiment of figures 2 to 5) or, in a variant not shown, may be attached to this base 3A.

[0037] The present invention is not limited to the embodiments described above as examples and extends to other variants.

Claims

Light module (2) integrated into the front or rear face of a vehicle, the light module (2) comprising a plastic housing (4) defining a housing (6) inside which are arranged: at least one light source (7) and an optical imaging system (5), the optical imaging system (5) being arranged opposite said at least one light source (7) and configured so as to generate a light beam, the plastic housing (4) comprising a bottom (3A);wherein the plastic housing (4) is provided with a part (10) extending vertically on its bottom (3A), in the housing (6), said part (10) being arranged between said at least one light source (7) and the optical imaging system (5), and being arranged on the bottom (3A) of the plastic housing (4) in such a way that its location on the bottom (3A) corresponds to an area located at or in front of a focusing area of ​​light rays coming from the sun and focused by the optical imaging system (5), said part (10) being configured so as to block the focused light rays coming from the sun while allowing the light rays coming from said at least one light source (7) to pass through and propagating towards the optical imaging system (5).; Light module (2) according to claim 1, in which said part (10) is attached to the bottom (3A) of the plastic housing (4). Light module (2) according to claim 1, wherein said part (10) is made in one piece with the plastic housing (4), in particular via injection molding. Light module (2) according to any one of the preceding claims, wherein said part (10) is made of a plastic or metallic material. Light module (2) according to any one of the preceding claims, in which said part (10) has a cutout (12) arranged opposite said at least one light source (7) to allow the passage of light rays coming from said at least one light source (7) and propagating towards the optical imaging system (5). Light module (2) according to any one of the preceding claims, wherein said part (10) has at least one protuberance (14) projecting towards the optical imaging system (5) and arranged on the bottom (3A) of the plastic housing (4) such that its location on the bottom (3A) corresponds to a focusing zone for light rays coming from the sun and focused by the optical imaging system (5), said at least one protuberance (14) having a shape such that it blocks the focused light rays coming from the sun upstream of a focusing point of these light rays. Light module (2) according to claim 6, wherein said at least one protuberance (14) has a truncated or pointed shape. A light module (2) according to any preceding claim, wherein the optical imaging system (5) is a direct optical imaging system. Vehicle lighting and / or signaling element comprising a light module (2) according to any one of the preceding claims. Vehicle headlight comprising a light module (2) according to any one of claims 1 to 8 or a lighting and / or signaling element according to claim 9.

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