EP1605201A1 - Vehicle lighting or signaling device with a light guide - Google Patents

Abstract

The device has an optical light guide (5) including an output side (FS) to output light rays propagated in the guide, where the side (FS) has a profile including ridges. The guide has a reflecting side (FR) with an indented profile forming a light rays reflecting side. The reflecting side has a series of prisms (8), where facets of consecutive prisms form a truncated base angle (D).

Description

The present invention relates to a lighting device and / or signaling equipment fitted to a motor vehicle, including at least one guide optical device capable of producing a homogeneous diffusion of light. This guide optical includes prisms that allow to deflect the light rays.

The invention finds applications in the field of vehicles traveling on roads and, in particular, motor vehicles.

• des dispositifs d'éclairage situés à l'avant du véhicule avec, notamment, des projecteurs de véhicules équipés de feux de croisement, ou codes, ayant une portée sur la route avoisinant 110 mètres, et de feux de route ayant une longue portée lumineuse et produisant une zone de vision sur la route avoisinant 200 mètres,
• des dispositifs d'éclairage situés à l'arrière du véhicule avec, notamment, les feux de recul,
• des dispositifs de signalisation situés à l'avant du véhicule avec, notamment, de feux de position, des indicateurs de direction et des D.R.L. (Daytime Running Light, en terme anglo-saxons) ou phares de jour (intégrés ou non aux projecteurs assumant les fonctions d'éclairage mentionnées plus haut), et
• des dispositifs de signalisation situés à l'arrière du véhicule avec, notamment, des feux antibrouillards, des feux arrière, des indicateurs de direction et des feux stop.

In the field of lighting and signaling of motor vehicles, we know different types of devices, among which we find essentially:

• lighting devices at the front of the vehicle including, inter alia, headlamps of vehicles equipped with low beam or code, with a range on the road of approximately 110 meters, and high beam with a long range of light and producing an area of vision on the road of about 200 meters,
• lighting devices at the rear of the vehicle including, in particular, the reversing lights,
• signaling devices located at the front of the vehicle with, in particular, position lights, direction indicators and DRLs (Daytime Running Light, in English term) or daytime headlights (integrated or not with the headlamps assuming the lighting functions mentioned above), and
• signaling devices at the rear of the vehicle including, but not limited to, fog lamps, taillights, direction indicators and brake lights.

Currently, it is known to use, in lighting devices or signaling devices, one or more optical guides for propagate a light beam. An example of a vehicle headlight is described in US-A-6,107,916. light source and an optical guide, placed near the source luminous and propagating the light beam emitted by this source light. This light guide can go along all or part of the ice or reflector of the projector.

• une source lumineuse 3, émettant un faisceau lumineux dont la direction d'émission est représentée par une flèche 4, et
• un guide optique 5, propageant ledit faisceau lumineux 4.

An example of a projector is shown in Figure 1. More specifically, Figure 1 shows schematically the left projector of a vehicle. This projector emits a light beam directed substantially towards the front of the vehicle, that is to say along the Y axis of the road. This projector 1 comprises a protective glass 2 forming the exit face of the projector 1. It also comprises:

• a light source 3, emitting a light beam whose emission direction is represented by an arrow 4, and
• an optical guide 5 propagating said light beam 4.

The optical guide 5 is a cylinder of transparent material provided with prisms, which ensures the propagation of the light beam 4 from a end e1 close to the light source 3 to an end e2 opposite to the end e1. This optical guide 5 can have different shapes Geometric. It can, for example, form a circle, an arc or to be rectilinear. In the case of Figure 1, the optical guide 5 follows the shape of the protective glass 2 of the projector 1.

• une première face 6 constituant une face de sortie des rayons lumineux propagés dans le guide optique 5 ; cette face de sortie 6 est lisse et continue ; et
• une deuxième face 7, opposée à la première face 6 et constituant une face de réflexion du guide optique ; cette face de réflexion 7 a un profil dentelé, c'est-à-dire un profil en forme des dents de scie. Cette face de réflexion 7 comporte une succession de prismes 8 identiques et symétriques. Ces prismes 8, placés côte à côte, forment les dents scie de la face de réflexion 7. Sur la figure 2, le guide optique 5 est représenté selon une vue en coupe. Pour une meilleure compréhension de la figure, il est représenté hachuré sur la figure 2. Ainsi, selon la vue en coupe selon la figure 2, chaque prisme 8 a une forme sensiblement triangulaire. Plus précisément, chaque prisme 8 a une forme de triangle comportant une base 14, une facette 9 et une facette 10, planes et non parallèles. Ces facettes 9 et 10 forment entre elles un angle A, appelé angle du prisme. Les facettes 9 et 10 forment, avec l'axe X du guide optique 5, respectivement, des angles B et C. La facette 9 d'un prisme et la facette 10 d'un prisme consécutif forment, ensemble, un angle de fond D. L'angle de fond D de chaque prisme est en contact avec une courbe appelée ligne de fond 11. Cette ligne de fond 11 relie le sommet de tous les angles D de la face de réflexion 6 du guide optique 5. Autrement dit, si on considère que chaque prisme 8 est un triangle, dans sa section, la ligne de fond 11 relie la base 14 de chaque triangle avec la base du triangle consécutif.On comprendra que la forme de chaque prisme est considérée comme triangulaire dans une vue de 2 dimensions.Sur la figure 2, on a représenté, par des flèches 12 et 13, un exemple d'une trajectoire d'un rayon lumineux se propageant dans un guide optique du type de celui décrit dans le document US-A- 6 107 916. Ce rayon lumineux peut être l'un des rayons lumineux contenus dans le faisceau lumineux 4 émis par la source lumineuse 3. Dans cet exemple, le rayon lumineux se propage dans le guide optique 5 selon une trajectoire initiale rectiligne 12 jusqu'à ce qu'il rencontre une facette d'un prisme. Cette trajectoire 12 forme, avec l'axe X du guide optique 5, un angle d'incidence E. Lorsqu'un rayon lumineux rencontre une facette d'un prisme, par exemple la facette 10 d'un prisme 8, dans le cas de la figure 2, la trajectoire 12 du rayon lumineux est déviée d'un angle F par rapport à la trajectoire initiale 12. La trajectoire déviée du rayon lumineux est référencée 13. L'angle de déviation F entre la trajectoire 12 et la trajectoire 13 est variable car lié notamment aux angles des prismes. Ainsi, le rayon lumineux est redirigé, par les prismes 8 de la face de réflexion 7, vers la face de sortie 6 du guide optique 5.Dans l'exemple de la figure 2, et par mesure de simplification de cette figure, la trajectoire d'un seul rayon lumineux a été représentée. Il est bien entendu que d'autres rayons lumineux avec d'autres trajectoires peuvent se propager dans le guide optique, ces rayons pouvant avoir été réfléchis une ou plusieurs fois, par un ou plusieurs prismes ou par l'autre face du guide optique, avant d'atteindre un prisme qui le redirige vers la face de sortie 6.Dans l'exemple de la figure 2, la déviation 13 du rayon lumineux répond au principe de la réflexion totale dans un guide optique. Le principe de la réflexion totale est un phénomène optique qui permet la transmission de la lumière dans un guide optique 5. Lorsqu'un rayon lumineux passe d'un milieu à un autre milieu possédant un indice de réfraction différent, sa direction est changée ; c'est l'effet de la réfraction. Pour un certain angle d'incidence, et si l'indice du milieu initial est supérieur à celui du milieu final, le rayon lumineux 12 n'est plus réfracté, il est réfléchi totalement : on parle de réflexion totale.Ainsi, si on considère à nouveau la figure 1, on comprend que le faisceau lumineux 4 doit être réparti sur toute la longueur du guide optique, c'est-à-dire entre l'extrémité e1 et l'extrémité e2. Or, une partie du faisceau lumineux 4 est perdue, avec des prismes constants, car le flux qui traverse la section diminue au fur et à mesure qu'il se propage. On comprend donc que, à l'extrémité e2 du guide optique 5, la quantité de lumière perdue est plus grande qu'à l'extrémité e1, proche de la source lumineuse 3. Autrement dit, le rendement lumineux est inférieur à l'extrémité e2 qu'à l'extrémité e1 du guide optique, ce qui a pour conséquence qu'il se produit une décroissance naturelle du flux de la lumière émise le long du guide optique. Or, cette décroissance est visible pour toute personne située en dehors du véhicule.Par ailleurs, Dans l'exemple de la figure 2, pour un angle d'incidence E compris entre 0 et 5 degrés, le rayon lumineux subit une réflexion totale. Ainsi, un rayon lumineux touchant une des facettes 9 ou 10 du prisme 8 est réfléchi vers la face de sortie 6 du guide optique 5, par le principe de la réflexion totale.En d'autres termes, les rayons lumineux qui arrivent avec un angle non parallèle à l'axe X du guide et, en particulier, lorsqu'ils forment un angle de 0 à 5° avec cet axe, sont redirigés vers la face de sortie 6 du guide optique grâce aux prismes 8. La présence des prismes 8 sur la face de réflexion 7 du guide optique 5 permet donc de faire sortir la lumière dans la bonne direction. Par le principe de la réflexion totale, le rayon lumineux est réfléchi vers la face de sortie du guide optique. En particulier, il est réfléchi avec une direction sensiblement perpendiculaire à l'axe X du guide optique 5, c'est-à-dire suivant la normale N à l'axe X. Une autre direction de réflexion du rayon lumineux peut être obtenue en modifiant l'angle B et/ou l'angle C du prisme. Dans ce cas, si l'on appelle G l'angle entre le rayon sortant du guide optique et la normale N, alors cet angle G ne peut être que positif. En d'autres termes, en modifiant la pente des prismes, il est possible de rediriger les rayons lumineux sortant de façon à avoir un angle G non nul.Or, dans certain cas, il est intéressant de pouvoir envoyer les rayons lumineux dans une direction formant un angle G négatif avec la normale N. Par exemple, dans le cas de la figure 1, on voit que le guide optique 5 suit le profil de la glace de protection 2 du projecteur 1. Par conséquent, les rayons lumineux réfléchis éclairent sur les côtés du véhicule, selon une direction Z. Comme on le comprend à la vue de la figure 1, le faisceau lumineux 4 émis par la source lumineuse 3 se propage dans le guide optique 5 jusqu'à son extrémité opposée e2. A proximité de cette extrémité e2, les rayons lumineux émis perpendiculairement à l'axe du guide optique éclairent la route latéralement, et sont vus par tout observateur sur le côté de la route. Ainsi, à cette extrémité e2 du guide optique 5, l'angle entre le guide optique 5 et la direction des rayons lumineux souhaitée Y n'est pas favorable. Ces rayons lumineux sont perdus, c'est-à-dire qu'ils sont réfléchis vers une direction inintéressante, ce qui diminue les performances espérées du dispositif d'éclairage ou de signalisation. L'invention a pour but de remédier aux inconvénients des techniques exposées précédemment. L'invention a notamment pour but d'améliorer les performances des guides lumineux, notamment d'améliorer leur aspect visuel à l'état allumé et/ou d'obtenir une plus grande souplesse dans le choix de l'angle de sortie des rayons lumineux émis par le guide de lumière. Elle a ainsi pour but d'améliorer/mieux contrôler l'émission de la lumière par les dispositifs d'éclairage et/ou de signalisation utilisant des guides de lumière, notamment d'améliorer l'homogénéisation de la lumière distribuée/émise par ces guides.Selon une première réalisation, elle propose tout d'abord un dispositif d'éclairage et/ou de signalisation à guide optique, dans lequel la lumière est répartie de manière uniforme et homogène le long du guide optique. Pour cela, l'invention propose un guide optique comportant une face de réflexion munie d'une succession de prismes, les angles situés entre deux prismes consécutifs de la face de réflexion étant, au moins pour certains, tronqués. Alternativement ou cumulativement, la face de sortie a un profil comportant des stries, configuration détaillée plus loin.Le terme de « prisme » indique qu'il s'agit de formes géométriques usuellement définies par des faces planes, mais il est également dans le cadre de l'invention de considérer des pseudo primes, assimilés à des prismes, mais dont l'une des faces est par exemple courbe, de façon plus ou moins prononcée.Le terme de « profil dentelé » indique que la face en question n'est pas entièrement plane, qu'elle comprend des reliefs, notamment mais pas seulement des prismes.De façon plus précise, l'invention concerne tout d'abord un dispositif d'éclairage ou de signalisation pour véhicule automobile comportant au moins une source lumineuse émettant un faisceau lumineux et au moins un guide optique dans lequel se propage le faisceau lumineux, ledit guide optique comportant
• une face, dite face de sortie du faisceau lumineux, et
• une autre face, dite face de réflexion, opposée à la face de sortie, ayant un profil dentelé formant une face de réflexion du faisceau lumineux et comportant une succession de prismes, chaque prisme formant, avec le prisme suivant, un angle de fond,

   avec au moins un angle de fond de la face de réflexion qui est tronqué.An example of the optical guide 5 of this projector is shown in more detail in Figure 2. This Figure 2 shows a sectional view of the optical guide 5. This optical guide 5 has two faces:

• a first face 6 constituting an exit face of the light rays propagated in the optical guide 5; this exit face 6 is smooth and continuous; and
• a second face 7, opposite the first face 6 and constituting a reflection face of the optical guide; this reflection face 7 has a serrated profile, that is to say a profile in the form of saw teeth. This reflection face 7 comprises a succession of identical and symmetrical prisms 8. These prisms 8, placed side by side, form the saw teeth of the reflection face 7. In Figure 2, the optical guide 5 is shown in a sectional view. For a better understanding of the figure, it is shown hatched in Figure 2. Thus, according to the sectional view according to Figure 2, each prism 8 has a substantially triangular shape. More specifically, each prism 8 has a triangle shape with a base 14, a facet 9 and a facet 10, flat and non-parallel. These facets 9 and 10 form between them an angle A, called the angle of the prism. The facets 9 and 10 form, with the axis X of the optical guide 5, respectively, angles B and C. The facet 9 of a prism and the facet 10 of a consecutive prism together form a bottom angle D The bottom angle D of each prism is in contact with a curve called bottom line 11. This bottom line 11 connects the vertex of all the angles D of the reflection face 6 of the optical guide 5. In other words, if it is considered that each prism 8 is a triangle, in its section, the bottom line 11 connects the base 14 of each triangle with the base of the consecutive triangle. It will be understood that the shape of each prism is considered triangular in a view of 2 In FIG. 2, arrows 12 and 13 show an example of a trajectory of a light ray propagating in an optical waveguide of the type described in US Pat. No. 6,107,916. This light ray may be one of the light rays contained in the light beam 4 emitted by the In this example, the light beam propagates in the optical guide 5 in a straight initial trajectory 12 until it encounters a facet of a prism. This trajectory 12 forms, with the axis X of the optical guide 5, an angle of incidence E. When a light ray encounters a facet of a prism, for example the facet 10 of a prism 8, in the case of 2, the path 12 of the light beam is deflected by an angle F with respect to the initial trajectory 12. The deflected trajectory of the light beam is referenced 13. The deflection angle F between the trajectory 12 and the trajectory 13 is variable because linked in particular to the angles of the prisms. Thus, the light ray is redirected, by the prisms 8 of the reflection face 7, to the exit face 6 of the optical guide 5.In the example of FIG. 2, and as a simplification measure of this figure, the trajectory of a single light ray has been represented. It is understood that other light rays with other trajectories may propagate in the optical guide, these rays may have been reflected one or more times, by one or more prisms or the other face of the optical guide, before to reach a prism that redirects it to the exit face 6. In the example of Figure 2, the deflection 13 of the light beam responds to the principle of total reflection in an optical guide. The principle of total reflection is an optical phenomenon that allows the transmission of light in an optical guide 5. When a light ray passes from one medium to another medium having a different refractive index, its direction is changed; it is the effect of refraction. For a certain angle of incidence, and if the index of the initial medium is greater than that of the final medium, the light ray 12 is no longer refracted, it is totally reflected: it is called total reflection. Thus, if we consider again Figure 1, it is understood that the light beam 4 must be distributed over the entire length of the optical guide, that is to say between the end e1 and the end e2. However, part of the light beam 4 is lost, with constant prisms, because the flow that passes through the section decreases as it spreads. It is therefore understood that at the end e2 of the optical guide 5, the amount of light lost is greater than at the end e1, close to the light source 3. In other words, the light output is less than the end e2 that at the end e1 of the optical guide, which has the consequence that there is a natural decrease in the flow of light emitted along the optical guide. However, this decay is visible to anyone outside the vehicle.By the way, In the example of Figure 2, for an angle of incidence E between 0 and 5 degrees, the light ray undergoes a total reflection. Thus, a light ray touching one of the facets 9 or 10 of the prism 8 is reflected towards the exit face 6 of the optical guide 5, by the principle of total reflection. In other words, the light rays arriving at an angle non-parallel to the axis X of the guide and, in particular, when they form an angle of 0 to 5 ° with this axis, are redirected to the outlet face 6 of the optical guide through prisms 8. The presence of prisms 8 on the reflection face 7 of the optical guide 5 thus allows the light to come out in the right direction. By the principle of total reflection, the light beam is reflected towards the exit face of the optical guide. In particular, it is reflected with a direction substantially perpendicular to the axis X of the optical guide 5, that is to say along the normal N to the axis X. Another direction of reflection of the light ray can be obtained by modifying the angle B and / or the angle C of the prism. In this case, if we call G the angle between the ray leaving the optical guide and the normal N, then this angle G can only be positive. In other words, by modifying the slope of the prisms, it is possible to redirect the outgoing light rays so as to have a non-zero angle G. Or, in certain cases, it is interesting to be able to send the light rays in one direction forming an angle G negative with normal N. For example, in the case of Figure 1, we see that the optical guide 5 follows the profile of the protective glass 2 of the projector 1. Therefore, the reflected light rays illuminate on the sides of the vehicle, in a direction Z. As understood in the view of Figure 1, the light beam 4 emitted by the light source 3 propagates in the optical guide 5 to its opposite end e2. Near this end e2, the light rays emitted perpendicularly to the axis of the optical guide light the road laterally, and are seen by any observer on the side of the road. Thus, at this end e2 of the optical guide 5, the angle between the optical guide 5 and the desired direction of light rays Y is not favorable. These light rays are lost, that is to say that they are reflected towards an uninteresting direction, which reduces the expected performance of the lighting or signaling device. The invention aims to overcome the disadvantages of the techniques described above. The object of the invention is in particular to improve the performance of the light guides, in particular to improve their visual appearance in the lit state and / or to obtain a greater flexibility in the choice of the angle of exit of the light rays. emitted by the light guide. Its purpose is thus to improve / better control the emission of light by lighting and / or signaling devices using light guides, in particular to improve the homogenization of the light distributed / emitted by these guides. According to a first embodiment, it firstly proposes an illumination and / or optical guide signaling device in which the light is uniformly and homogeneously distributed along the optical guide. For this, the invention proposes an optical guide having a reflection face provided with a succession of prisms, the angles between two consecutive prisms of the reflection face being, at least for some, truncated. Alternatively or cumulatively, the output face has a profile with streaks, configuration detailed below. The term "prism" indicates that it is about geometric shapes usually defined by plane faces, but it is also in the frame of the invention to consider pseudo primes, similar to prisms, but one of whose faces is for example curved, more or less pronounced.Le term "serrated profile" indicates that the face in question is not not completely flat, it includes reliefs, including but not only prisms.Further details, the invention relates first of all to a lighting or signaling device for a motor vehicle comprising at least one light source emitting a light beam and at least one optical guide in which the light beam propagates, said optical guide comprising
• a face, said output face of the light beam, and
• another face, said reflection face, opposite to the exit face, having a serrated profile forming a reflection face of the light beam and comprising a succession of prisms, each prism forming, with the following prism, a bottom angle,

with at least one bottom angle of the reflection face which is truncated.

• certains au moins des angles de fond de la face de réflexion comportent une zone tronquée, la dimension de la zone tronquée étant variable d'un angle à un autre. Une telle zone tronquée permet de moduler et de contrôler le rendement de chaque prisme, c'est-à-dire le flux sortant localement d'un prisme par rapport au flux total traversant la section du guide au niveau de ce prisme, et d'optimiser l'aspect homogène de la lumière émise par le guide optique tout au long de sa longueur.
• la dimension des zones tronquées diminue au fur et à mesure de l'éloignement de la source lumineuse ;
• la face de réflexion comporte à la fois des prismes à angle de fond tronqué et des prismes à angle de fond non tronqué ;
• selon une première variante, les prismes ont des pas variables et une hauteur constante, ce qui permet de moduler le rendement de chaque prisme tout en modulant l'effet visuel ;
• selon une seconde variante (associable à la précédente), les prismes ont un pas constant et des hauteurs variables, ce qui permet également de moduler le rendement de chaque prisme, avec une réalisation simple à mettre en ceuvre ;
• le pas des prismes a une dimension de l'ordre de 0,2 à 2 mm ;
• la hauteur des prismes est de l'ordre de 0,2 à 2 mm ;
• les prismes (ou au moins un de ceux-ci) de la face de réflexion sont symétriques. Ce mode de réalisation est préférable lorsque le dispositif comporte plusieurs sources lumineuses (notamment une à chaque extrémité du guide)
• les prismes (ou au moins un de ceux-ci) de la face de réflexion sont dissymétriques, ce qui permet un meilleur rendement des prismes, et est préférable également quand une seule source lumineuse est utilisée pour alimenter le guide,

According to this first embodiment, the invention may include one or more of the following features:

• at least some of the bottom angles of the reflection face comprise a truncated zone, the size of the truncated zone being variable from one angle to another. Such a truncated zone makes it possible to modulate and control the efficiency of each prism, that is to say the flux exiting locally from a prism with respect to the total flux passing through the section of the guide at this prism, and of optimize the homogeneous appearance of the light emitted by the light guide along its length.
• the size of the truncated areas decreases as the light source moves away;
• the reflection face comprises both truncated bottom-angle prisms and non-truncated bottom-angle prisms;
• according to a first variant, the prisms have variable steps and a constant height, which makes it possible to modulate the output of each prism while modulating the visual effect;
• according to a second variant (which can be associated with the previous one), the prisms have a constant pitch and variable heights, which also makes it possible to modulate the output of each prism, with a realization that is simple to implement;
• the pitch of the prisms has a dimension of the order of 0.2 to 2 mm;
• the height of the prisms is of the order of 0.2 to 2 mm;
• the prisms (or at least one of them) of the reflection face are symmetrical. This embodiment is preferable when the device comprises several light sources (in particular one at each end of the guide).
• the prisms (or at least one of them) of the reflection face are asymmetrical, which allows a better performance of the prisms, and is also preferable when a single light source is used to feed the guide,

According to a second embodiment, alternative or cumulative with the previous one, the invention proposes a lighting and / or signaling device in which the optical guide comprises a serrated profile reflection face and a striated profile exit face. Such an exit face has the advantage of straightening an additional angle the light rays reflected by the reflection face, so as to obtain light rays coming out of the optical guide with a negative angle relative to the normal to the X axis (the negative sign is understood in relation to the mean direction of propagation of the light in the guide)
, which offers a great flexibility in the choice of the exit angles of the light rays coming out of the optical guide.

• une face, dentelée, dite face de réflexion et comportant une succession de prismes, et
• une autre face, opposée à la première face, formant une face de sortie du faisceau lumineux,

   telle que la face de sortie a un profil comportant des stries.More specifically, the invention according to this second embodiment relates to a lighting and / or vehicle signaling device comprising at least one light source emitting a light beam and an optical guide adapted to propagate said light beam, said optical guide comprising :

• a face, serrated, said reflection face and comprising a succession of prisms, and
• another face, opposite to the first face, forming an exit face of the light beam,

such that the exit face has a profile with streaks.

• chaque strie de la face de sortie est située en regard d'un prisme de la face de réflexion, ce qui permet de collecter les rayons intéressants qui ont été réfléchis par le prisme auquel elle est associée.
• les stries de la face de sortie ont chacune (pour au moins l'une d'entre elles au moins) une forme courbe, notamment en arc de cercle, ce qui permet de réaliser une déviation variable d'un rayon lumineux provenant d'un même prisme, ce qui crée un étalement des rayons lumineux, donc une homogénéisation de l'aspect allumé du guide optique dans toutes les directions.
• les stries (pour au moins l'une d'entre elles au moins) ont chacune une forme de prisme à facettes planes. Ce mode de réalisation est simple à mettre en oeuvre et permet, sur le plan optique, de privilégier une direction d'émission des rayons lumineux.
• chaque (au moins un des) prisme est symétrique. Ce mode de réalisation est préférable lorsque le dispositif comporte plusieurs sources lumineuses.
• chaque (au moins un des) prisme est dissymétrique, ce qui permet un meilleur rendement des prismes, le rendement étant à comprendre comme le flux lumineux sortant localement d'un prisme par rapport au flux total traversant la section du guide au niveau de ce prisme,
• les stries (pour au moins l'une d'entre elles au moins) comportent chacune une facette en arc de cercle et une facette plane. Ce mode de réalisation permet de cumuler les avantages des deux modes de réalisation précédents (forme en arc de cercle et forme de prisme). En outre, il permet de limiter les perturbations vis-à-vis des rayons qui continuent leur propagation dans le guide optique.
• les stries (pour au moins deux elles au moins) de la face de sortie sont contiguës.
• les stries (pour au moins deux elles au moins) de la face de sortie sont non contiguës.
• chaque strie ((pour au moins l'une d'entre elles au moins) comporte un angle de strie, par rapport à un axe du guide optique, de l'ordre de 1 à 30°, de préférence de 5 à 20°.
• dans le cas où les prismes de la face de sortie comportent chacun une première facette et une seconde facette, la seconde facette formant un angle de fond avec la première facette d'un prisme consécutif, certains au moins des prismes de la face de réflexion comportent un angle de fond tronqué. Un tel angle de fond tronqué permet de moduler et de contrôler le rendement de chaque prisme, c'est-à-dire le flux sortant localement d'un prisme par rapport au flux total traversant la section du prisme, et d'optimiser l'aspect homogène du guide optique.

Such a device makes it possible to deviate in a controlled manner the rays coming from the prisms. The lighting and / or signaling device according to the second embodiment of the invention may comprise one or more of the following characteristics:

• each streak of the exit face is located opposite a prism of the reflection face, which makes it possible to collect the interesting rays which have been reflected by the prism with which it is associated.
• the streaks of the exit face each have (for at least one of them at least) a curved shape, in particular in an arc of a circle, which makes it possible to achieve a variable deflection of a light ray coming from a same prism, which creates a spread of light rays, so a homogenization of the lit appearance of the optical guide in all directions.
• the streaks (for at least one of them at least) each have a flat-faceted prism shape. This embodiment is simple to implement and allows, optically, to favor a direction of emission of light rays.
• each (at least one) of the prism is symmetrical. This embodiment is preferable when the device comprises several light sources.
• each (at least one) of the prism is asymmetrical, which allows a better performance of the prisms, the output being to be understood as the luminous flux coming out locally of a prism with respect to the total flux passing through the section of the guide at the level of this prism ,
• the streaks (for at least one of them at least) each comprise an arcuate facet and a flat facet. This embodiment makes it possible to combine the advantages of the two previous embodiments (arcuate shape and prism shape). In addition, it makes it possible to limit the disturbances with respect to the rays which continue their propagation in the optical guide.
• the ridges (for at least two of them) of the exit face are contiguous.
• the ridges (for at least two of them) of the exit face are non-contiguous.
• each streak (for at least one of them at least) has a stripe angle, with respect to an axis of the optical guide, of the order of 1 to 30 °, preferably 5 to 20 °.
• in the case where the prisms of the exit face each comprise a first facet and a second facet, the second facet forming a bottom angle with the first facet of a consecutive prism, at least some of the prisms of the reflection face comprise a truncated bottom angle. Such a truncated bottom angle makes it possible to modulate and control the efficiency of each prism, that is to say the flux coming locally from a prism with respect to the total flux passing through the section of the prism, and to optimize the homogeneous appearance of the optical guide.

• les sources lumineuses peuvent être de type halogène, être des diodes électroluminescentes, ou tout autre lampe comme des lampes xénon par exemple,
• le dispositif d'éclairage ou de signalisation peut comporter au moins deux sources lumineuses placées chacune à une extrémité du guide optique (sources lumineuses standard de type halogène ou diodes électroluminescentes par exemple) : le guide optique peut alors propager la lumière à partir des deux extrémités, ce qui permet d'avoir des guides d lumière de grande longueur.
• le dispositif d'éclairage ou de signalisation peut comporter plusieurs guides optiques ayant une intersection commune, au moins une source lumineuse étant située à ce point d'intersection. on a alors un guide de lumière « ramifié », avec de préférence une source au niveau des ramifications, et éventuellement à au moins une des extrémités des branches d'un tel guide.

As well according to the first as according to the second realization:

• the light sources may be of halogen type, be light-emitting diodes, or any other lamp such as xenon lamps for example,
• the lighting or signaling device may comprise at least two light sources each placed at one end of the optical guide (standard halogen-type light sources or light-emitting diodes, for example): the optical guide may then propagate the light from both ends , which allows to have light guides of great length.
• the lighting or signaling device may comprise a plurality of optical guides having a common intersection, at least one light source being located at this point of intersection. then there is a branched light guide, preferably with a source at the branches, and possibly at least one end of the branches of such a guide.

La figure 1, déjà décrite, représente un exemple de projecteur de véhicule muni d'un guide optique.

La figure 2, déjà décrite, représente une vue en coupe d'un guide optique de l'art antérieur.

La figure 3 représente une vue en coupe d'un exemple de guide optique à troncature, selon l'invention.

La figure 4 représente une vue en coupe d'un premier mode de réalisation d'un guide optique à troncature variable selon l'invention.

La figure 5 représente une vue en coupe d'un second mode de réalisation d'un guide optique à troncature variable selon l'invention.

La figure 6 représente une vue en coupe d'un guide optique selon l'invention dans le cas où la face de sortie du guide est striée.

La figure 7 représente un premier mode de réalisation d'un guide optique selon l'invention ;

La figure 8 représente un second mode de réalisation d'un guide optique selon l'invention ;

Les figures 9A et 9B représentent un troisième mode de réalisation d'un guide optique selon l'invention

The invention also relates to a motor vehicle equipped with at least one lighting or signaling device according to this first embodiment and / or this second embodiment of the invention, as well as the light guide itself.

Figure 1, already described, shows an example of a vehicle headlight with an optical guide.

Figure 2, already described, shows a sectional view of an optical guide of the prior art.

FIG. 3 represents a sectional view of an example of a truncation optical guide, according to the invention.

FIG. 4 represents a sectional view of a first embodiment of a variable truncation optical guide according to the invention.

FIG. 5 represents a sectional view of a second embodiment of a variable truncation optical guide according to the invention.

FIG. 6 represents a sectional view of an optical guide according to the invention in the case where the outlet face of the guide is ridged.

FIG. 7 represents a first embodiment of an optical guide according to the invention;

FIG. 8 represents a second embodiment of an optical guide according to the invention;

FIGS. 9A and 9B show a third embodiment of an optical guide according to the invention

Figures 1 to 5 relate more specifically to the invention according to the first realization.

Figures 7 to 9 relate more specifically to the invention according to the second realization.

Figure 6 relates more specifically to the invention combining the first and second embodiments according to the invention.

The invention will be described below with the aid of two examples, and in both cases, relates to a lighting or signaling device to guide optical system allowing a homogeneous and uniform diffusion of the light. The device of the invention may be a projector like that of FIG. well a signaling device. Whether it's a projector or a signaling device, the optical guide has characteristics ensuring a homogeneous and uniform appearance to the light at the exit of the guide optical. In the remainder of the description, a projector will be described, being understood that it can be also a signaling device.

According to the first embodiment, an example of an optical guide according to the invention, which can be mounted in a projector of FIG. shown in FIG. 3. In the example which will be described, the device considered is a position light located in a headlamp at the front of a vehicle. Also, the optical guide, in this example, is curved and forms a circle or an arc. It is understood that the optical guide, according to the invention may have other forms such as, for example, rectilinear, curve with one or more curvatures ....

This FIG. 3 shows a sectional view of an optical guide intended to propagate a light beam emitted by the light source 3. In this embodiment, the optical guide 5 has a circular section; it is well heard that it can also, in other embodiments, have a elliptical section, square, oval, even square etc.

• une première face FS constituant une face de sortie des rayons lumineux propagés dans le guide optique 5 ; cette face de sortie 6 peut être lisse et continue, comme sur les figures 3 à 5 ou bien comporter des stries, comme montré ultérieurement sur la figure 6;
• une deuxième face FR, opposée à la première face FS, constituant une face de réflexion du guide optique 5 ; cette face de réflexion FR comporte une succession de prismes 8. Ces prismes 8 sont placés côte à côte et assurent une réflexion des rayons lumineux ayant un angle d'incidence non nul avec l'axe X du guide optique 5.

This optical guide 5 has two faces:

• a first face FS constituting an output face of the light rays propagated in the optical guide 5; this exit face 6 may be smooth and continuous, as in FIGS. 3 to 5 or may comprise ridges, as shown later in FIG. 6;
• a second face FR, opposite to the first face FS, constituting a reflection face of the optical guide 5; this reflection face FR comprises a succession of prisms 8. These prisms 8 are placed side by side and provide a reflection of the light rays having a non-zero incidence angle with the axis X of the optical guide 5.

According to a sectional view of the optical guide 5, each prism 8 has a substantially triangular shape; each prism has a base 14, a facet 9 and a facet 10, flat and non-parallel. The facet 9 and the facet 10 of a prism 8 may be symmetrical with respect to a T axis perpendicular to the X axis of the optical guide, that is to say that they have dimensions and angles B and C identical, on both sides of the bisector T. It is said that the optical guide is symmetrical prisms. The facet 9 and facet 10 may also be asymmetrical, i.e. they have different dimensions and / or angles B and C. We say then that the optical guide is asymmetrical prisms.

The facet 10 of a prism 8 and the facet 9 of a consecutive prism together form a bottom angle D. According to the invention, the bottom angle D a prism 8 is truncated. In other words, at least some of the angles of bottom D have a truncated area. This truncated area of the angle of bottom D forms a flat part 16. A flat part 16 is therefore a flat part of the bottom line curve 11 shown in dashed lines in FIG. the example of FIG. 3, the bottom line 11 coincides with the X axis of the optical guide 5.

Everything happens as if the space between two prisms 8 formed an air prism 15: then, in the invention, the air prism 15 of the type "Clipped". In this case, the clipping of the air prisms 15 is made according to a section of the vertices of said air prisms. This section is performed along the curve of the bottom line 11.

As will be seen more precisely later, the flats 16 of the bottom angles D are preferably of geometrical shape of type rectangle. They can have different dimensions. These dimensions of flats can vary from one light guide to another. They can also be variable within the same optical guide. In this case, the flats 16 may have different dimensions for each bottom angle D associated with each prism. Some background angles D may also not 16. In this case, the optical guide 5 comprises at the same time bottom angles D with flats 16 and bottom corners D without flat, by example alternately. For example, the size of the flats can be chosen in a decreasing manner from the end e1 towards the end e2 of the optical guide in order to propagate a maximum of light rays towards the end e2.

According to the invention, the bottom angle D between two prisms 8 is truncated, which allows a light beam to propagate in the optical guide 5 without touching one of the facets 9 or 10 of the prism. Because of this, the radius light is reflected by the flat to the exit face FS so as to to be fully reflected. He then continues his spread in the guide optical.

For example, near the end e1 of the optical guide, a most of the light rays, emitted by the light source 3, are not not thinking, because they do not meet facets 9 or 10 prism. These light rays continue their propagation in the optical guide 5 as if there was no prism. These light rays are thus directed towards the end e2 of the optical guide 5. The properties of the reflection face FR are therefore modified by the presence of these flats. In this way, between the ends e1 and e2 of the optical guide 5, the luminous flux coming out of optical guide can be uniformly distributed over the entire length of the optical guide by this phenomenon of flat.

The invention also makes it possible to obtain, at the output of the optical waveguide, a flux light distributed, voluntarily, non-uniformly. In this case uneven distribution is controlled to achieve a particular visual effect, for example an alternation of illuminated and unlit areas.

Thus, the bottom angles D make it possible to adjust the light input of the prisms 8 in the optical guide 5. It is understood that an optical guide 5 according to the invention makes it possible to compensate for the decrease in the luminous flux traversing the optical guide between the end e1 and the end e2.

Uniform or uniform but controlled distribution of the flow light is preferably obtained by means of flat dimensions variables and, more precisely, the width of the flats along the X axis variable. In a preferred embodiment, the size of the flats 16 is decreasing from the end e1 towards the end e2 of the optical guide 5. This reduction in the size of the flats 16 makes it possible to optimize the guiding the light rays propagating in the optical guide 5. A near the end e1, the size of the flats 16 is large, thus allowing much of the light rays not to meet facet 9 or 10 of prism and so to continue their spread towards the end e2. Near the end e2, the dimension flats 16 is smaller and smaller until it is zero. There is then a large amount of light rays that meet one of the facets 9 or 10 of a prism. These light rays are then reflected towards the face of FS output of the optical guide 5.

This reduction in the size of the flats 16 makes it possible to compensate for the natural luminous decay and, consequently, to uniformly regulate the luminance (ie the luminous intensity emitted by m ² ) at any point in the guide. 5. As a result, the optical guide 5, as a whole, has a homogeneous appearance.

In other embodiments, the size of the flats may be be growing from the end e1 to the end e2, or angles of flat bottom can alternate with bottom corners without flat, etc.

• le pas 17 entre deux prismes est constant. On entend par « pas » 17 la longueur reliant le sommet d'un prisme avec le sommet du prisme consécutif. Le pas 17 est représenté par une double flèche, sur la figure 4. En d'autres termes, le pas 17 correspond à la base du prisme d'air 15. Le pas 17 entre deux prismes est de préférence de l'ordre de 0,2 à 2 millimètres
• la hauteur 18 des prismes 8 est variable. On appelle « hauteur » 18 la distance entre un point d'une courbe Z et un point du ligne de fond 11 du guide optique 5. La courbe Z, représentée en pointillés sur la figure 4, est une courbe reliant le sommet des angles A de chaque prisme. La hauteur 18 est représentée par une double flèche sur la figure 4. De préférence, la hauteur 18 est de l'ordre de 0,2 à 2 millimètres.

FIG. 4 shows a first embodiment of a variable truncation optical guide, that is to say the size of the flats of which is variable. In the example of Figure 4, the flats 16 have decreasing dimensions between the end e1 and the end e2 of the optical guide 5, as explained above. As seen in the sectional view of the optical guide 5 of Figure 4, the flats 16a, 16b, ... 16n have different dimensions from each other and, more specifically, decreasing dimensions. This decrease is obtained by modulating the height of the prisms. More precisely, in the example of FIG.

• step 17 between two prisms is constant. The term "step" 17 is the length connecting the apex of a prism with the apex of the consecutive prism. Step 17 is represented by a double arrow in FIG. 4. In other words, pitch 17 corresponds to the base of air prism 15. Step 17 between two prisms is preferably of the order of 0 , 2 to 2 millimeters
• the height 18 of the prisms 8 is variable. The distance between a point of a curve Z and a point of the bottom line 11 of the optical guide 5 is called "height". The curve Z, shown in dashed lines in FIG. 4, is a curve connecting the apex of the angles A of each prism. The height 18 is represented by a double arrow in FIG. 4. Preferably, the height 18 is of the order of 0.2 to 2 millimeters.

In the embodiment of FIG. 4, the height 18 of a prism 8 increases in proportion to the decrease in the size of the flat 16 corresponding. The reflection face FR is contained between two curves, the along the optical guide. One of the curves is the bottom line 11 and the other curve is the curve Z.

• le pas 17 entre deux prismes est variable. Le pas 17 est représenté par une double flèche sur la figure 5. Le pas 17 entre deux prismes est de préférence inférieur ou égal à 2.5 mm, notamment de l'ordre de 0,2 à 2 millimètres ;
• la hauteur 18 des prismes 8 est constante. La hauteur 18 est représentée par une double flèche sur la figure 5. La hauteur 18 est inférieure ou égale à 2.5 mm, notamment de l'ordre de 0,2 à 2 millimètres. Dans ce mode de réalisation, le pas 17 d'un prisme 8 diminue proportionnellement à la diminution de la taille du méplat 16 correspondant. La hauteur 18 étant constante, la courbe Z est parallèle à l'axe X du guide optique 5.

FIG. 5 shows a second embodiment of an optical guide 5 with variable truncation. As in the case of FIG. 4, the flats 16 have decreasing dimensions between the end e1 and the end e2 of the optical guide 5. As can be seen in the sectional view of the optical guide 5 of FIG. flats 16a, 16b, ... 16n have decreasing dimensions. In this embodiment, the decay is obtained by modulating the pitch of the prisms. More precisely, in the example of FIG.

• step 17 between two prisms is variable. Step 17 is represented by a double arrow in FIG. 5. The pitch 17 between two prisms is preferably less than or equal to 2.5 mm, in particular of the order of 0.2 to 2 millimeters;
• the height 18 of the prisms 8 is constant. The height 18 is represented by a double arrow in FIG. 5. The height 18 is less than or equal to 2.5 mm, in particular of the order of 0.2 to 2 millimeters. In this embodiment, the pitch 17 of a prism 8 decreases in proportion to the decrease in the size of the flat 16 corresponding. Since the height 18 is constant, the curve Z is parallel to the axis X of the optical guide 5.

The two embodiments that have just been described allow both to achieve a decrease in the size of the flats. In addition, they offer the same light output and the same homogeneity of the light emitted by the optical guide 5 over its entire length. The choice of one or the other of these embodiments depends on the visual aspect, even aesthetic, wanted.

Are now described Figures 7 to 9, corresponding to a second example according to the second embodiment:

A first embodiment of this optical guide according to the invention is shown in FIG. 7. In this FIG. reflection carries the reference FR and the exit face bears the reference FS, with the same conventions as before.

In the device of the invention, the reflection face FR of the guide optical may be identical / similar to the reflection face of the optical guide previously described. This reflection face is provided with a succession of prisms 8 placed one after the other so as to form a face to serrated profile. The prisms 8 may be identical and symmetrical one to others, as in the prior art, or else identical and asymmetrical or different from each other.

In the case where the prisms 8 are asymmetrical, as shown in FIG. 7, a reflection is obtained at an angle of about 90.degree. ratio to the X axis for light rays having an angle of incidence of the order of 10 to 40 ° with respect to the X axis of the optical guide. Indeed, in this case, what can be considered as an air prism 30 is formed by the background of prism that precedes prism 8 in transparent matter; this prism air 30 ensures rectification of the incident light beam. In other words, if we consider that reflection face of the optical guide includes prisms in transparent material 8 interposed by air prisms 30, then these air prisms 30 change the trajectory of the light rays in straightening the rays of light before they meet a prism 8. For example, in FIG. trajectory light beam 17 adjusted with an angle of incidence E included between 10 and 40 ° with respect to the X axis of the optical guide. This light ray 17 is deflected and straightened along a path 18 by the air prism 30 before to be reflected by the facet 10 of the prism 8. It is then redirected, following the path 19, towards the exit face FS of the optical guide in one direction preferred overall perpendicular to the axis X of the guide.

Another example of a light ray has been shown in FIG. This light beam, of trajectory 21, has an angle of incidence E 'of approximately 5 ° relative to the X axis of the optical guide. This light ray is therefore in the configuration of a total reflection by the prism in matter 8. This ray 21 is reflected, by the facet 10 of the prism 8, at an angle of approximately 90 ° to the X axis to the FS exit face of the optical guide. In the case of a light ray having an angle incidence close to the tangent, that is to say between 0 and 5 ° by compared to the X axis, then the asymmetric prisms have the same effect on the light ray than symmetrical prisms. On the other hand, as we saw above, asymmetric prisms have a recovery effect, in addition of the reflection effect, when the light beam has an angle of incidence of 10 at 40 °. Asymmetric prisms therefore make it possible to increase the yield light towards the exit face 6 of the optical guide.

According to the invention, the output face FS of the optical guide has a striated profile. In other words, the FS exit face has streaks that make it possible to straighten again the light rays at the exit of the guide optical. These striations are reliefs (bosses or hollows) made in the face output 6 of the optical guide. They can be of different shapes.

In the embodiment of FIG. 7, these striations 24 each have a form of prism, that is to say that each stripe 24 has two facets 25 and 26, planes. A facet 26 of a streak and a facet 25 of a consecutive streak together form a bottom angle H of about 90 °. The facet 25 of a strip 24 forms, with the axis X of the optical guide, an angle of streak K of the order of 10 to 20 °. Thus, as shown in Figure 7 and 8, the streaks 24 of the FS exit face have a lower depth than the prisms 8 of the reflection face FR, this in order to keep the optical guide its guiding characteristics. Just like the prisms of the face of FR reflection that form a bottom line 11 of the prisms, the streaks form a bottom line 16 of the streaks. In other words, the bottom of each streak 24 (by opposition at the top of the streaks) forms with the bottom consecutive streaks a curve called bottom line 16 of the streaks. Streaks 24 are therefore contained between the bottom line 16 and a curve connecting the top of all the striations 24, these two curves generally following the profile of the guide.

These prism-shaped striations may be symmetrical or, at contrary, asymmetrical as shown in Figure 7.

In a first variant, all the streaks of the same guide optics are identical. In a second variant, the streaks are different, that is to say that they have a stripe angle K and / or an angle of bottom H which can vary between the end e1 of the guide and the end e2, so to allow an evolutionary reflection of light rays along the entire length of the guide.

Whatever their shape, each streak 24 of the output face FS is located opposite a prism 8 of the FR reflection face. Streaks 24 of the FS output face therefore have a pitch identical to the pitch of the prisms 8 of the face reflection FR. In other words, to be effective, the active areas of the FS exit face, that is to say the facets 25 streaks 24, are located in face (at least partially opposite) of the active areas of the prisms 8 of the reflection face FR, that is to say the facets 10 of the prisms 8.

Thus, in the example of FIG. 7, the light beam of trajectory incoming 17 undergoes, as previously explained, a first reflection by the facet 10 of a prism 8. It is then refracted by the facet 25 of a streak 24 and out of the optical guide with a negative angle G relative to the normal N to the axis X. Similarly, the light ray 21 undergoes the same path from the facet 10 of the prism. The exit angle G thus obtained depends on course of the slope of the stripe 24. In the example of Figure 3, this exit angle G is of the order of -20 ° relative to normal N.

This embodiment of the output face in prisms thus allows to send light rays in a direction impossible to reach by total reflection on the prisms of the reflection face when the exit face is smooth. It makes it possible to obtain a negative angle G of approximately -25 ° with respect to the normal N.

According to FIG. 7, the angle between the mean direction of propagation in the optical guide and the mean direction of exit of the ray light out of the optical guide is obtuse: such an angle can not be obtained with a smooth exit face. In Figure 8, there is shown another mode embodiment of the output face FS of the optical guide of the invention. In this embodiment, the streaks 24 do not have flat facets; at otherwise, the ridges 24 have a curved profile. More precisely, according to a view in section, each stripe 24 has an arcuate shape. In other words, each streak 24 forms a kind of dome forming, with the consecutive streak, a bottom angle H. The tangent at the base of the dome makes an angle K of 10 ° to 20 ° with respect to the X axis of the optical guide.

Each stripe 24 of the output face FS is located opposite a prism 8 of the reflection face FR. Streaks 24 therefore have an identical pitch at the pitch of the prisms 8 of the reflection face FR. In other words, streaks 24 of the FS exit face are located opposite the active areas of the prisms 8 of the reflection face FR.

This embodiment has the advantage of allowing a controlled distribution of light around the normal N, which allows to homogenize the appearance of the guide for an outside observer. For that, two examples of light rays have been shown in Figure 8, which may have different directions at the output of the optical guide.

The first example of a light ray is the light ray of incoming trajectory 17 having an angle of incidence E, from 10 to 40.degree. to the X axis. This light ray is first deflected by an air prism 30 then reflected by about 90 ° by a prism 8 to the output face FS. when encountering a streak 24 of the output face FS, said light beam is subjected to refraction of a negative angle G with respect to the normal N (path 20).

The second example of light ray is the trajectory radius incoming 21 having an angle of incidence E 'with the axis X. This light ray 21 undergoes a first reflection by a prism 8 of the reflection face FR. When it encounters a groove 24 of the exit face 6, said light ray 21 undergoes refraction with a positive angle G relative to normal N (trajectory 23). This profile in domes of the output face FS thus makes it possible to distribute the light laterally in several directions.

In FIG. 9A, a third embodiment of FIG. the exit face of the optical guide of the invention. In this mode of realization, the ridges 24 of the exit face FS form faceted prisms curve. More specifically, each streak 24 has a curved facet 28 and a plane facet 27, each curved facet 28 being consecutive to a flat facet 27. The curved facet 28 and the flat facet 27 of a streak consecutively together form a bottom angle H of the order of 90 °. The tangent to the curved facet 28 forms, along with the X axis of the optical guide, a streak angle K of the order of 10 to 20 °. In this embodiment, the Striations are contiguous to each other, ie a streak is contiguous to the next streak. This third embodiment associates features of the first embodiment with features of the second embodiment, which makes it possible to optimize the guidance of the radii light through the optical guide, while guaranteeing good homogeneity of light and a sending of light in directions classically inaccessible.

As shown in FIG. 9A, the first example of radius light 17 is refracted, by a streak 24 of the exit face 6, with a angle G negative relative to normal N. The second example of radius light 21 out of the optical guide with a negative angle G relative to the normal N, different from the angle G formed by the light beam 20. However, as seen in Figure 9A, depending on the location on the streak, the value of the exit angle G differs. So we understand that the angle of output G varies depending on the location, on the facet 28 of the streak 24, the point of contact of the light ray with the streak. In other words, the value the angle of exit depends on the radius of curvature of the curved facet 28. Thus, by modifying the curvature of the curved facets 28 of the striations 24, it is possible to get a whole range of exit angles. In other words, a such a curved prism outlet face makes it possible to obtain at the same time an effect of prism and a burst effect of the light beam.

FIG. 9B shows a variant of the embodiment of Figure 9A. In this variant, the ridges 24 of the FS exit face form curved non-contiguous facet prisms. More precisely, each groove 24 has a curved facet 28 and a flat facet 27, each curved facet 28 being separated from the flat facet 27 of the streak The striations 24 are therefore separated from each other by a flat surface. 29 In this variant, the active zone of each streak 24, that is to say the curved facet 28, is placed opposite (at least partially) of the active area of the prism 8, that is to say the facet 10 of the prism in order to make refraction by the streaks as efficient as possible. The 29, in this variant, makes it possible to propagate at the end e2, the light rays not refracted by streaks 24.

In Figure 6 is shown a light guide, according to a third realization, which is modified both on its exit face and on its face of reflection according to the invention: the exit face 6 has ridges which make it possible to straighten the light rays at the output of the optical guide, that is to say to get them out of the optical guide with a negative angle relative to normal N to the X axis of the guide., as shown in FIG. the reflection face comprises prisms such as those described using the Figure 4 in particular. Associate the two embodiments of the invention on a same light guide is very advantageous.

The streaks of the output face FS can be of different shapes, for example, in the form of prisms or domes or a combination of prisms and domes, as seen above with figures 7 and 8. They are located opposite the active areas of the prisms 8 of the face reflection.

The prisms of the reflection face can be those described in FIG. 3, 4 or 5. The presence of flats 15 in the optical guide makes it possible a light beam, to propagate in the optical guide without touching a facets 9 or 10 of the prisms 8 of the reflection face FR. As a result, the light beam is reflected back to the exit side of the light guide, further in the guide, which distributes the luminous flux uniformly between the ends e1 and e2 of the optical guide.

It should be noted that the examples described above, and, more generally, the light guides according to the invention have sections of circular preference, since such a section is the most appropriate in terms of optical guidance. This section is also very appropriate in terms of focusing of light. But the invention also light guides of different section, for example a section of conical shape, for example of elliptical, hyperbolic or parabolic, at least partially, or oval. Type sections parallelogram, square, rectangle are also possible but less interesting in terms of light guidance.

Also note that, both for the streaks of the exit face that for the prisms of the reflection face, streaks and / or prisms can have variable widths (ie, affect more or less the width of the face in question, either wholly or partially, either with a variable width along the length of the guide).

The invention therefore proposes two light guide embodiments, alternatives, or cumulative, to have a better visual homogeneity of the guide once turned on and / or have more control over the orientation of the light emitted by the light guide. To cumulate the two achievements is very advantageous, because they contribute to the same goal, that of improving the visual light guides once lit.

Claims (19)

Lighting and / or signaling device for a motor vehicle comprising at least one light source (3) emitting a light beam (4) and at least one optical guide in which the light beam (4) propagates, said light guide comprising an output face (FS) of the light beam, and another reflection face (FR), opposite to the exit face, having a serrated profile forming a reflection face of the light beam characterized in that the reflection face (FR) comprises a succession of prisms (8), each prism (8) forming, with the following prism (8), a bottom angle (D), with at least one bottom angle (D) of the reflection face (FR) which is truncated and / or in that the exit face (FS) has a profile with grooves (24) Lighting and / or signaling device according to the preceding claim, characterized in that at least some of the bottom angles (D) of the reflection face (FR) comprise a truncated area (16), the size of the truncated area being variable from one angle to another. Lighting and / or signaling device according to claim 2, characterized in that the size of the truncated areas (16) of the reflection face (FR) decreases as the light source (3) moves away from the light source. ). Lighting and / or signaling device according to any one of the preceding claims, characterized in that the reflection face (FR) comprises both truncated bottom angle prisms and non-truncated bottom angle prisms. Lighting and / or signaling device according to any one of the preceding claims, characterized in that the prisms of the reflection face (FR) have variable steps (17) and a constant height (18). Lighting and / or signaling device according to any one of Claims 1 to 4, characterized in that the prisms of the reflection face (FR) have a constant pitch (17) and variable heights (18). Lighting and / or signaling device according to claim 5 or 6, characterized in that the pitch (17) of the prisms of the reflection face (FR) has a dimension less than or equal to 2.5 millimeters, in particular of the order from 0.2 to 2 millimeters. Lighting and / or signaling device according to any one of Claims 5 to 7, characterized in that the height (18) of the prisms of the reflection face (FR) is less than or equal to 2.5 millimeters, in particular order of 0.2 to 2 millimeters. Lighting and / or signaling device according to any one of the preceding claims, characterized in that the prisms of the reflection face (FR) are symmetrical. Lighting and / or signaling device according to any one of claims 1 to 8, characterized in that the prisms of the reflection face (FR) are asymmetrical. Lighting and / or signaling device according to one of the preceding claims, characterized in that each streak (24) of the exit face (FS) is located opposite a prism (8) of the reflection face (EN). Lighting and / or signaling device according to one of the preceding claims, characterized in that the striations of the output face (FS), or at least one of them, each have a curved shape, in particular in an arc circle. Lighting and / or signaling device according to one of Claims 1 to 11, characterized in that the striations of the exit face (FS), or at least one of them, each have a prism shape, in particular flat facets (25, 26). Lighting and / or signaling device according to Claim 13, characterized in that the prisms of the output face (FS) are symmetrical or asymmetrical. Lighting and / or signaling device according to one of Claims 1 to 12, characterized in that the ridges (24) of the exit face (FS) each comprise a curved facet (28) and a flat facet (27). ). Lighting or signaling device according to any one of the preceding claims, characterized in that the ridges (24) of the exit face (FS) are contiguous or non-contiguous. Lighting and / or signaling device according to any one of the preceding claims, characterized in that each streak of the output face (FS) forms a striation angle (K) with an axis (X) of the optical guide, of the order of 1 to 30 °. Lighting and / or signaling device according to one of the preceding claims, characterized in that it comprises at least two light sources each placed at one end of the optical guide. Lighting and / or signaling device according to any one of the preceding claims, characterized in that it comprises several optical guides having a common intersection, at least one light source being located at this point of intersection.

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