EP1422470B1 - Headlamp for vehicle with enlarged lighting field - Google Patents

Description

The present invention relates to a projector device, intended to be used in particular in a motor vehicle, which provides an illuminated range widened compared to certain projectors of the state of the art. The object of the invention is essentially to propose an improvement in existing elliptical-type projector devices, which notably have a very small illuminating surface. By illuminating surface, or illuminating surface, denotes an area at the output of a projector device, from which the light comes.

• des feux de position, d'intensité et de portée faible ;
• des feux de croisement, ou codes, d'intensité plus forte et de portée sur la route avoisinant 70 mètres, qui sont utilisés essentiellement la nuit et dont la répartition du faisceau lumineux est telle qu'elle permet de ne pas éblouir le conducteur d'un véhicule croisé ;
• des feux de route longue portée, et des feux de complément de type longue portée, dont la zone de vision sur la route avoisine 200 mètres, et qui doivent être éteints lorsque l'on croise un autre véhicule afin de ne pas éblouir son conducteur ;
• des projecteurs perfectionnés, dits bimodes, qui cumulent les fonctions de feux de croisement et de feu de route en incorporant un cache amovible ;
• des feux anti-brouillard.

The field of the invention is, in general, that of motor vehicle headlights. In this field, we know different types of projectors, among which we find essentially:

• position, intensity and low range lights;
• low beam, or codes, of greater intensity and range on the road of about 70 meters, which are used mainly at night and whose distribution of the light beam is such that it does not dazzle the driver of a crossover vehicle;
• long-range headlamps, and long-range supplement lights, whose vision zone on the road is approximately 200 meters, and which must be extinguished when crossing another vehicle so as not to dazzle its driver;
• advanced projectors, called dual mode, which combine the functions of low beam and high beam by incorporating a removable cover;
• fog lights.

The projector device according to the invention finds its application primarily in use as dipped headlamps, but it could nevertheless be used in any other type of projector device cited. Describing the invention in the context of low beam is therefore in no way limiting to this application alone.

• La première famille est celle des projecteurs dits paraboliques. Dans ce type de projecteurs, un faisceau lumineux est engendré par une source lumineuse de petite dimension disposée dans un réflecteur, ou miroir. La projection sur la route des rayons lumineux réfléchis par un réflecteur approprié permet d'obtenir directement un faisceau lumineux obéissant aux différentes contraintes imposées par les normes. Un tel dispositif projecteur peut éventuellement être complété par une surface de sortie de type glace, qui peut être munie par exemple de stries pour modifier le faisceau lumineux, par exemple en l'étalant en largeur. Cette famille de projecteurs inclut les projecteurs dits à surface libre, ou surface complexe, qui permettent d'obtenir directement un faisceau lumineux présentant une ligne de coupure désirée. La plage éclairante de ce type de projecteurs est relativement importante.

In the field of projectors, there are two main families that correspond to two distinct arrangements of elements within the projectors:

• The first family is that of so-called parabolic projectors. In this type of projectors, a light beam is generated by a small light source disposed in a reflector, or mirror. The projection on the road of the light rays reflected by a suitable reflector makes it possible to directly obtain a light beam obeying the various constraints imposed by the standards. Such a projector device may optionally be supplemented by an ice-type exit surface, which may be provided for example with ridges for modifying the light beam, for example by spreading it in width. This family of projectors includes so-called free-surface projectors, or complex surfaces, which make it possible to obtain directly a light beam having a desired cut-off line. The illuminating surface of this type of projectors is relatively important.

The second family is that of so-called elliptical projectors. It is in this type of projectors that the object of the invention finds its main interest. In this family of projectors, a spot of light concentration is generated by a light source arranged in a mirror. The spot of light concentration is then projected onto the road by a convergent lens, for example a plano-convex lens. In order to obtain a break in the light beam produced by the device, the light concentration spot is partially obscured, for example by means of a metal cover disposed within the projector device.

• d'une part, un conducteur antagoniste risque d'être trompé par la petite taille de la plage éclairante, et croire ainsi que le véhicule produisant une telle plage éclairante est plus éloigné qu'il ne l'est en réalité;
• d'autre part, le contraste visuel entre le dispositif projecteur elliptique et les éléments qui l'entourent est très important. Or ce contraste accentue fortement les effets d'éblouissements pour le conducteur antagoniste. En effet, on sait que, à niveau d'éclairement identique, plus la plage éclairante est petite, plus la concentration de lumière est importante sur au moins une partie de la rétine d'un oeil, et plus le phénomène d'éblouissement est fort.

A specific feature of elliptical projectors, which is largely attenuated in parabolic spotlight devices, is that the illuminating surface is very small; it corresponds in fact to the exit surface of the lens, whose diameter typically varies between 40 millimeters and 70 millimeters. This small illuminating surface has two main problems:

• on the one hand, an opposing driver may be deceived by the small size of the illuminating surface, and thus believe that the vehicle producing such an illuminating surface is farther away than it actually is;
• on the other hand, the visual contrast between the elliptical projector device and the surrounding elements is very important. This contrast strongly accentuates the effects of glare for the opposing driver. Indeed, it is known that, at identical illumination level, plus the illuminating surface is small, the higher the concentration of light on at least a portion of the retina of one eye, and the more the glare phenomenon is strong.

• une première solution consistant en l'utilisation d'anneaux de Fresnel qui entourent la lentille et un intermédiaire, l'intermédiaire étant une pièce qui permet de maintenir la lentille et qui est solidaire du réflecteur;
• une deuxième solution consistant en l'utilisation d'un anneau dépoli qui entoure l'intermédiaire et la lentille.

In the state of the art, various embodiments have been proposed to supplement the main illuminating surface, defined by the projection lens, with a complementary projection range in order to increase the total illuminating area of an elliptical projector device; to create the complementary lighting range, several solutions have been proposed, among which we find in particular:

• a first solution consisting of the use of Fresnel rings which surround the lens and an intermediate, the intermediate being a piece which holds the lens and which is integral with the reflector;
• a second solution consisting in the use of a frosted ring which surrounds the intermediate and the lens.

An essential problem of these solutions appears in the figure 1 . This figure schematically shows a projector device 100 of elliptical type, comprising in particular a light source 101, a reflector 102, an intermediate 103, a cover 104, a projection lens 105 and a lens holder 106. To illuminate the Fresnel rings or the frosted ring, not shown, light signals 107 of direct light are used, ie light coming directly from the light source 101 without having been reflected by the reflector 102. light 106 pass through the intermediate 103 via openings specially provided for this purpose.

• en présence du cache 104, il est difficile d'envoyer de la lumière dans la partie basse de l'anneau ; la plage éclairante complémentaire, et donc la plage éclairante totale, n'est alors pas homogène ;
• l'intermédiaire 103 doit être ouvert le plus possible afin de faire parvenir à l'anneau autant de lumière directe que possible, et afin de lui donner un aspect homogène, notamment en l'absence de cache. Cependant, en ouvrant l'intermédiaire 103, on fragilise le dispositif projecteur 100, car, du fait du poids important de la lentille 105, les risques de rupture sont augmentés de façon significative en cas de choc.

Such a structure, however, poses two essential problems:

• in the presence of the cover 104, it is difficult to send light into the lower part of the ring; the complementary illuminating surface, and therefore the total illuminating surface, is not homogeneous;
• the intermediate 103 must be opened as much as possible in order to give the ring as much direct light as possible, and to give it a homogeneous appearance, especially in the absence of cache. However, by opening the intermediate 103, it weakens the projector device 100 because, because of the significant weight of the lens 105, the risk of rupture is significantly increased in case of impact.

It is an object of the invention to respond to the problems that have just been exposed. In a general way, it is proposed in the invention a projector device which allows, while retaining the conventional structure of elliptical projectors devices, to obtain a larger illuminating surface than that of the devices of the state of the art without modifying the structure of existing intermediaries, and in particular without weakening them with openings.

For this purpose, in the invention, it is proposed to deform an area of the lens to deflect a portion of the light signals reaching said lens to send these signals to a ring reflector disposed around the lens. The light signals that are deflected may be direct or indirect light; in addition, the deformation of the lens is such that it allows light input both in the upper part and in the lower part of the ring reflector so as to homogenize the complementary illuminating surface produced by the ring reflector. This characteristic remains valid even in the presence of a cache in the projector device. The zone of deformation of the lens is preferably chosen so as not to modify the main light beam, initially produced by the lens, which must meet certain standards. In some embodiments of the device according to the invention, provision may be made to ensure continuity between the projection lens and the ring reflector in the visual impression of the assembly, ie a driver antagonist does not see a non-luminous area between the initial illuminating surface produced by the lens and the complementary illuminating surface produced by the ring reflector.

The invention therefore essentially relates to a projector device comprising in particular a light source emitting a set of light signals, a main reflector for reflecting at least a portion of said main light signals and a projection lens for diffusing a light beam, the projection lens comprising at least one protuberance for deflecting a set of light signals to a ring reflector disposed at the periphery of the projection lens.

A projector device of this kind is known to US 4,949,226 and EP 1 052 449 .

The ring reflector may consist of a single piece or a juxtaposition of reflective elements. It can also be in the form of a ring portion only.

• chaque protubérance est disposée au niveau d'au moins une partie du pourtour de la lentille de projection ;
• l'ensemble des signaux déviés est constitué de signaux de lumière directe et/ou indirecte;
• une partie supérieure du réflecteur principal comporte au moins une strie pour dévier des signaux lumineux vers une partie inférieure de la lentille de projection ;
• la déviation des signaux lumineux déviés par chaque protubérance s'effectue radialement ;
• au moins une protubérance est en forme de strie présentant une première face, dite face de réflexion, et une deuxième face, dite face de diffusion, les signaux lumineux déviés par chaque protubérance étant essentiellement, notamment totalement, réfléchis par la face de réflexion puis essentiellement, notamment totalement diffusés par la face de diffusion ;
• la face de diffusion et/ou la face de réflexion sont courbées pour dévier les signaux lumineux sur la totalité de la largeur du réflecteur en anneau ;
• le réflecteur en anneau présente une section horizontale parabolique ;
• les signaux lumineux déviés reçus par le réflecteur en anneau sont réfléchis dans une direction voisine d'un axe optique du dispositif projecteur ;
• le dispositif projecteur comporte une source lumineuse secondaire pour produire des signaux lumineux essentiellement, notamment exclusivement destinés à être déviés par au moins une desdites protubérances ;
• chaque protubérance est disposée sur une face de sortie de la lentille de projection.

The device according to the invention may furthermore present one or more following characteristics:

• each protuberance is disposed at at least a portion of the periphery of the projection lens;
• the set of deviated signals consists of direct and / or indirect light signals;
• an upper portion of the main reflector has at least one stripe for deflecting light signals to a lower portion of the projection lens;
• the deflection of the light signals deflected by each protuberance takes place radially;
• at least one protrusion is in the form of a streak having a first face, said reflection face, and a second face, said diffusion face, the light signals deflected by each protuberance being essentially, in particular totally, reflected by the reflection face then essentially , in particular totally diffused by the diffusion face;
• the diffusion face and / or the reflection face are curved to deflect the light signals over the entire width of the ring reflector;
• the ring reflector has a parabolic horizontal section;
• the deflected light signals received by the ring reflector are reflected in a direction close to an optical axis of the projector device;
• the projector device comprises a secondary light source for producing luminous signals essentially, especially exclusively intended to be deflected by at least one of said protuberances;
• each protuberance is disposed on an exit face of the projection lens.

Another object of the invention is a motor vehicle equipped with at least one projector device having at least one of the characteristics which have just been described.

• à la figure 1, déjà décrite, une représentation schématique d'un dispositif projecteur elliptique de l'état de la technique présentant une plage éclairante élargie ;
• à la figure 2, une représentation schématique d'un dispositif projecteur selon l'invention ;
• à la figure 3, une coupe horizontale d'une partie d'un premier exemple de réalisation du dispositif projecteur selon l'invention ;
• à la figure 4, une coupe horizontale d'une partie d'un deuxième exemple de réalisation du dispositif projecteur selon l'invention.

The invention and its various applications will be better understood by reading the following description and examining the figures that accompany it. These are only indicative and not at all limiting of the invention.

• to the figure 1 , already described, a schematic representation of an elliptical projector device of the state of the art having an enlarged illuminating surface;
• to the figure 2 , a schematic representation of a projector device according to the invention;
• to the figure 3 , a horizontal section of a portion of a first embodiment of the projector device according to the invention;
• to the figure 4 , a horizontal section of a portion of a second embodiment of the projector device according to the invention.

In the different figures, the elements that are common to several figures will have retained the same references. On the Figures 2 to 4 schematically a projector device 200 according to the invention. The figure 2 shows a light source 201 disposed within a main reflector 202. A projection lens 203 is traversed at its center by an optical axis 204, the optical axis 204 also supporting the light source 201. For the sake of clarity of the figure 2 , the intermediate and the cache, which may be present in some embodiments, of the projector device 200 have not been shown.

The projection lens 203 is surrounded by a ring reflector 205. It also has on its exit face 207, that is to say the face accessible from outside the projector device, two deformed zones 206 which cut with the usually smooth appearance of this exit face. These areas correspond to protuberances; they mark a rupture by revealing a protruding zone on at least one of the usually smooth faces of the lenses used. The protuberances are disposed on almost the entire lateral periphery of the lens 203. By lateral periphery is meant the zone of the lens located near its periphery, with the exception of the high and low peaks of this lens. In other exemplary embodiments, the protuberances 206 can meet at its high and low peaks and thus perform a complete turn of the lens 203.

The light source 201 produces a set of light signals 208, part of which is brought to meet the protuberances 206, whether directly, this is the case of direct light, or after reflection, it is the in the case of the so-called indirect light, at the main reflector 202. The light signals encountering a protuberance 206 are deflected, preferably radially, ie in a plane approximately perpendicular, to within 10 degrees, to the optical axis 204 They then reach the reflective surface of the ring reflector 205, and are scattered in a predetermined direction.

In order to reach the parts of the protuberances 206 which are located on the lower part of the lens 203, and which are therefore not accessible by direct light when a cover is arranged, provision is made in the invention to produce a set of striations 209 on the reflective surface of the reflector 202. In a preferred embodiment, streaks 209 are made at places where the light that is reflected is not used or little used in the main beam produced by the projector device 200. , the provision of ridges at an upper cheek 210 of the main reflector 202 will be favored. The number and arrangement of the streaks 209 is determined so as to obtain a uniform distribution of the luminous intensity reflected by the ring reflector 205. 209 are not essential for some elliptical projectors devices without cache.

Details on the deflection of the light signals at the protuberances 206 are given to the Figures 3 and 4 , which show two different examples of deflection, according to two embodiments of the device according to the invention.

To the figure 3 , which represents a horizontal section of the projection lens 203 associated with the ring reflector 205. Incident light rays 211, of direct and / or indirect light, reach the lens 203 at an entry surface 212 of this lens . The light rays are not necessarily contained in a horizontal plane, those shown correspond to a projection on the plane of rays meeting the protuberance 206 at this plane.

The incident rays 211 undergo a first deflection at the input surface 212 and are directed towards one of the protuberances 206 disposed on an exit face 207 of the projection lens 203. Each protuberance 206 corresponds to a prism which is characterized in particular by a first face 213 and a second face 214. The first face 213 is a reflection face of the incident rays 211. In the example of the figure 3 the reflection face is flat; it is arranged such that an angle defined between a normal to this surface and the rays which strike it is greater than a limit reflection angle, so that the incident rays 211 are totally reflected at the reflection surface 213 .

The light rays 211 are then directed towards the second face 214, which is a diffusion face. The light signals may or may not undergo a new deflection at the diffusion face 214 to be sent to the reflective face of the ring reflector 205. The shape of the reflective surface of the ring reflector 205 is such that the light signals are reflected. in a previously determined direction. Typically, a horizontal section of this reflective surface is a parabolic arc. In a particular embodiment, the signals reflected by the ring reflector 205 are scattered in a direction substantially parallel to the optical axis, more precisely in a direction corresponding to the normalized point B50L.

The set of light signals diffused by the ring reflector 205 constitutes a complementary beam 216 which is thus produced by a complementary illuminating surface. The complementary illuminating surface thus corresponds to the surface of the ring reflector 205 actually used to reflect light signals. As we see in figure 3 , the complementary beam 216 obtained in this embodiment is relatively narrow and is not directly adjacent to the main light beam directly from the projection lens 203.

Embodiments of the projector device 200, for example the one illustrated in FIG. figure 4 , in which a complementary light beam 217 is wider than the complementary light beam 216. For this purpose, there is provided a reflection face 215 which is no longer flat, but curved. The normal to the reflection face 215 has a direction that varies in each point of this reflection face; as a result, incident light signals 211, which arrive in parallel directions on this face, are not reflected in parallel directions as they were in the example of FIG. figure 3 . The curvature of the reflection face 215 is calculated so that the incident rays are transmitted to the entire reflecting surface of the annular reflector 205. Thus, a wider complementary bundle 217 is obtained which, moreover, because of the proximity between the ring reflector 205 and the projection lens 203, is directly adjacent to the main light beam directly produced by the lens 203. In an alternative embodiment of the example of the figure 4 , instead of or in combination with the curved reflection face 215, a curved diffusion face 214 is chosen so as to also obtain an enlarged complementary light beam 217.

In general, the various deflections experienced by the light rays at the level of the protrusions 206 have the effect of radially diffusing, ie in a plane approximately perpendicular to the optical axis 204, a set of light rays which are thus capable of reaching the reflective surface of the ring reflector in its entire circumference, whether the protuberances 206 meet or not at the upper and lower ends of the lens 203.

In another variant embodiment of the device according to the invention, there is provided a light source annexed to the light source 201, this auxiliary light source being essentially or exclusively intended to emit signals towards the protuberances 206; this embodiment makes it possible in particular to prevent the striations 209 from being made on the reflector in order to be able to reach the lower part of the protuberances 206 in the case where the projector device comprises a cover.

Claims (10)

1. Headlight device (200) comprising a light source (201) emitting a set of light signals, a main reflector (202) for reflecting at least some of said light signals and a projection lens (203) for diffusing a main light beam, the projection lens (203) comprising at least one protuberance (206) for diverting a set of light signals towards a ring reflector (205) disposed at the periphery of the projection lens (203), each protuberance (206) being disposed at at least part of the circumference of the projection lens (203), characterised in that at least one protuberance (206) is in the form of a serration having a first face (213;
   215), referred to as the reflection face, and a second face (214) referred to as the diffusion face, the light signals diverted by each protuberance (206) being essentially, in particular completely, reflected by the reflection face (213; 215) and then essentially, in particular completely, diffused by the diffusion face (214).
2. Headlight device (200) according to at least one of the preceding claims, characterised in that the set of diverted signals consists of direct and/or indirect light signals.
3. Headlight device (200) according to at least one of the preceding claims, characterised in that a top part of the main reflector (202) comprises at least one serration (209) for diverting light signals towards a bottom part of the projection lens (203).
4. Headlight device (200) according to at least one of the preceding claims, characterised in that the diversion of the light signals diverted by each protuberance (206) takes place radially.
5. Headlight device (200) according to the preceding claim, characterised in that the diffusion face (214) and/or the reflection face (213; 215) are curved so as to divert the light signals over most, in particular the whole, of the width of the ring reflector (205).
6. Headlight device (200) according to at least one of the preceding claims, characterised in that the ring reflector (205) has a parabolic horizontal section.
7. Headlight device (200) according to at least one of the preceding claims, characterised in that the diverted light signals received by the ring reflector (205) are reflected in a direction close to an optical axis (204) of the headlight device (200).
8. Headlight device (200) according to at least one of the preceding claims, characterised in that it comprises a secondary light source for producing light signals essentially, in particular exclusively, intended to be diverted by at least one of said protuberances (206).
9. Headlight device (200) according to at least one of the preceding claims, characterised in that each protuberance (206) is disposed on an exit face (207) of the projection lens (203).
10. Motor vehicle equipped with a headlight device (200) according to at least one of the preceding claims.

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