EP2006604A1 - Optical module for vehicular lighting device - Google Patents

Abstract

The present invention relates to an optical module (M) for a motor vehicle lighting device comprising:
a reflector (R) defining an optical axis (X),
a dioptric element (L),
a light source (S) arranged between the reflector and the dioptric element,
a folder (P) arranged between the source and the dioptric element and comprising a transparent block (B) whose upper face (F _top ) is parallel to the optical axis (X) and is provided at least partially with a reflective coating (Re).

Description

The present invention relates to an optical module for automobile lighting device of the projector type. It applies more particularly to optical modules called elliptical modules comprising a light source associated with a reflector and closed by a dioptric element of the convergent lens type, for example a plano-convex lens, Fresnel lens. The invention is also concerned with optical modules equipped with a fixed or movable cover able to intercept at least partially, depending on its position, the light beam emitted by the light source / reflector assembly. The shape of the upper edge of the cache makes it possible to define the desired cut in the beam by imaging with the convergent lens.

For more details on mobile cache modules, refer to the patents EP 1 197 387 , EP 1 422 471 or EP 1 442 472 . The mobile cover, on command and thanks to the presence of a motor, can take different positions with respect to the light source, including at least one position called "active" optically, that is to say a position where it obscures actually a part of the light beam, in particular for the module to emit a cut-off beam, such as a crossing beam (part of the cut being oblique) or anti-fog (with a horizontal cut). The cache may thus have one or more "active" positions, for example two, one for the traffic crossing function on the right and one for the traffic function on the left, and also a so-called "passive" function where it does not block the beam. light, thus allowing the module to emit light beams without cutoff of the road beam type. For examples of fixed-cache modules, one can refer in particular to the patent FR 2 75 4039 , which describes modules able to emit crossover or fog beams for example.

It is already known from the patent EP 1 746 340 an elliptical module with cover, which is further provided with a "bender", that is to say an optical function element which is able to deflect the rays emitted by the source or reflected by the reflector. In this patent, the folder is a reflective surface disposed between the cover and the light source, and which can be an integral part of the cache itself.

The aim of the invention is an optical module, for example an elliptical module, which offers improved optical performance, and more particularly improved performance in the context of the emission of an uninterrupted beam of the road type.

• un réflecteur définissant un axe optique,
• un élément dioptrique,
• une source lumineuse disposée entre le réflecteur et l'élément dioptrique,
• une plieuse disposée entre la source et l'élément dioptrique et comportant un bloc transparent dont la face supérieure est munie au moins partiellement d'un revêtement réfléchissant.

The invention firstly relates to an optical module for a motor vehicle lighting device comprising

• a reflector defining an optical axis,
• a dioptric element,
• a light source arranged between the reflector and the dioptric element,
• a folder disposed between the source and the dioptric element and having a transparent block whose upper face is provided at least partially with a reflective coating.

• soit ne pas perturber de façon significative la direction ou l'intensité des rayons qui le traversent, quand il est constitué par exemple d'un parallélépipède,
• soit au contraire imposer une déviation prédéterminée à ces rayons, de manière à ce qu'ils soient dirigés vers des zones particulières du faisceau lumineux émergeant du module.

In the present description, will be called "transparent" a block that can be crossed by light rays. This block can be made of glass, or be made of transparent plastic, the choice being made in particular taking into account the thermal stresses in the module (different depending on the type of light source used). Such a transparent block can thus:

• either does not significantly disturb the direction or the intensity of the rays passing through it, when it consists for example of a parallelepiped,
• or rather to impose a predetermined deviation to these rays, so that they are directed to particular areas of the light beam emerging from the module.

By "reflective coating" is meant a reflective layer which can be deposited, for example by a vacuum deposition technique, on the upper face of the transparent block, or which can be attached to this face by any means. (This coating is advantageously reflecting on at least one of its faces, particularly its upper face once the folder in the mounting position, and in particular reflecting on both sides.)

The invention proposes here a new design of "folding" which is very advantageous: the "active" part of the folder, that is to say the reflective coating, being supported by this transparent block which does not interfere, or very little, with the light rays emitted by the source, or on the contrary which interferes in a controlled manner with these rays, one can eliminate the parasitic effects of a support which would be, for example, of metal.

Preferably, the optical module is intended to emit at least one road-type uninterrupted beam, the upper face of the deflecting bender upwards at least some of the rays emitted by the source and / or reflected by the reflector in order to increase the maximum intensity of said beam. The module can therefore be simply a single function module: a road module only.

• soit n'intercepte quasiment pas la lumière, et ne crée pas de coupure involontaire,
• soit dévie de manière contrôlée les rayons lumineux qui le traversent de manière à ce qu'ils apportent une contribution à des zones prédéterminées du faisceau route.

It is in the context of the emission of a road beam that this type of folder is indeed very interesting, since the transparent block support:

• or almost does not intercept the light, and does not create an involuntary break,
• or deviates in a controlled manner light rays that pass through it so that they make a contribution to predetermined areas of the road beam.

It is also in this context that its use is the most unexpected: indeed, it is in a road configuration that the design of a module is the simplest: there is no need to use a cache to make a cut. But here we still added this folder, and it turned out, surprisingly, that its presence had a very positive impact on the value of maximum intensity obtained in the beam.

Preferably, the transparent block is disposed substantially perpendicular to the optical axis of the module, symmetrically with respect to this axis.

According to a variant, at least a portion of at least one of the right, left, front or rear side walls of the transparent block is made opaque, or diffusing, in particular by local metallization or by frosting or by association with an occulting element. In this variant, it is preferable to opacify rather the block in the lower part of at least one of the lateral, right, left, front and rear faces: this operation is intended, if necessary, to replace a static mask, sometimes present even to make road beams, in order to delimit them clearly.

The transparent block may have right, left, front and rear side walls parallel to each other: this is its simplest embodiment. One can thus have a block which is simply substantially in the form of a parallelepiped. One can also have a block of which at least one of its side walls is curved. In this case, and contrary to what was stated previously, we will change the shape of the wall so that the transparent block can play an optical role, in the manner of a lens, and in particular influence the photometric distribution of the beam emitted by the module.

The transparent block may also have a hexahedron shape, that is to say six-sided polyhedron, whose volume is delimited by two parallel rectangular faces and four trapezoidal lateral faces.

The transparent block may have a flat upper face: this is its simplest embodiment. But it can also be envisaged that it is at least locally curved, especially along length. Again, this is a parameter that can be used to influence the photometric distribution of the emitted beam.

According to one variant, the module is a multi-module, in particular two functions. In this case, it also comprises a cover, which is arranged between the folder and the dioptric element: the cover is in particular mounted movably between at least one optically active position and a retracted position. The optically active position of the cache corresponds to the emission by the module of a cut-off beam, in particular of the code type, and its retracted position corresponds to the emission by the module of an uninterrupted beam, in particular of the road type. It may then be preferable that the cover be able to make the folder at least partially ineffective optically when it is in the optically active position.

An "optically active position" is understood to mean a position of the cache such that it intercepts a portion of the rays emitted directly by the source or reflected by the reflector.

• que le cache puisse soit intercepter les rayons réfléchis par la plieuse, notamment en étant disposé devant elle et en ayant un bord supérieur plus haut que les points les plus hauts de la face supérieure de la plieuse,
• et/ou que la configuration cache /plieuse soit telle que les rayons réfléchis par la plieuse et qui ne seraient pas interceptés par le cache constituent un apport négligeable dans la constitution du faisceau émis par le module, notamment parce que les rayons réfléchis par la plieuse sont « perdus », c'est-à-dire qu'ils passent au dessus du cache mais n'entrent pas ensuite dans l'élément dioptrique (car trop « hauts »), et/ou parce qu'ils entrent dans l'élément dioptrique mais qu'ils en ressortent de façon diffuse, étant défocalisés par rapport à l'élément dioptrique, se retrouvant notamment dans la partie inférieure du faisceau du module et n'en constituant qu'un apport minime).

It is understood by "optically inefficient folder" the fact

• that the cache can intercept the rays reflected by the folder, in particular by being arranged in front of it and having an upper edge higher than the highest points of the upper face of the folder,
• and / or that the cache / bender configuration is such that the rays reflected by the folder and which are not intercepted by the cover constitute a negligible contribution in the constitution of the beam emitted by the module, in particular because the rays reflected by the folder are "lost", that is to say they pass over the cache but do not enter the dioptric element (because too "high"), and / or because they enter the dioptric element but that they emerge in a diffuse way, being defocused by relative to the dioptric element, found in particular in the lower part of the beam of the module and constituting only a minimal contribution).

Similarly, it is understood by "partially optically inefficient folder" that when the cover is optically active position, it only partially intercepts the rays reflected by the reflective surface of the folder, the rays that are not intercepted by the cache and which are not "lost" contributing to increase the performance of the cut-off beam, and in particular its range.

To do this, one possibility is that the cover has, in the optically active position, its upper edge at a height such as that of the upper face of the block of the folder that it intercepts a part of the rays reflected by the upper face. reflective coating thereof.

The dioptric element is in particular a lens.

The light source equipping the module may be a filament lamp, or a xenon arc lamp, or a light emitting diode or a group of light emitting diodes.

The invention also relates to a motor vehicle headlight which comprises an optical module as described above.

• La figure 1 est une représentation schématique un module elliptique mono fonction destiné à émettre un faisceau de type route selon l'art antérieur
• La figure 2 est une représentation schématique un module elliptique mono fonction destiné à émettre un faisceau de type route selon une première variante de l'invention,
• Les figures 3 et 4 sont les représentations simplifiées des isolux des faisceaux route obtenus respectivement par le module selon la figure 1 et par le module selon la figure 2
• La figure 5 est une représentation d'une autre de plieuse selon l'invention.
• La figure 6 est une représentation schématique d'un module elliptique mono fonction destiné à émettre un faisceau de type route selon une seconde variante de l'invention,
• Les figures 7, 8 et 9 sont des représentations schématiques un module elliptique bi fonction destiné à émettre un faisceau de type code et de type route, selon une troisième variante de l'invention,
• les figures 10A et 10B sont des représentations schématiques en perspective d'une variante de plieuses selon l'invention,
• les figures 11A, 11B et 11C sont des représentations schématiques en coupe longitudinale par un plan vertical contenant l'axe optique du module elliptique d'autres variantes de plieuses selon l'invention, et
• la figure 12 est une représentation simplifiée des isolux du faisceau route obtenu par le module équipé de la plieuse selon les figures 10A et 10B.

The invention will be detailed with reference to the description below of nonlimiting exemplary embodiments and to the appended figures which illustrate them:

• The figure 1 is a schematic representation of a single-function elliptical module intended to emit a road-type beam according to the prior art
• The figure 2 is a schematic representation of a single-function elliptical module for emitting a road-type beam according to a first variant of the invention,
• The Figures 3 and 4 are the simplified representations of the isolux of the route beams obtained respectively by the module according to the figure 1 and by the module according to the figure 2
• The figure 5 is a representation of another folder according to the invention.
• The figure 6 is a schematic representation of a single-function elliptical module for emitting a road-type beam according to a second variant of the invention,
• The Figures 7, 8 and 9 schematic representations of an elliptical module bi function intended to emit a code-type beam and of the road type, according to a third variant of the invention,
• the Figures 10A and 10B are diagrammatic representations in perspective of a variant of folders according to the invention,
• the Figures 11A, 11B and 11C are diagrammatic representations in longitudinal section through a vertical plane containing the optical axis of the elliptical module of other variants of folders according to the invention, and
• the figure 12 is a simplified representation of the isolux of the road beam obtained by the module equipped with the folder according to the Figures 10A and 10B .

All these figures are deliberately very schematic, very simple and not necessarily scaled to facilitate reading.

The term "front", "back", "up", "down", "upper" or "lower" is understood throughout the present text according to the position of the module once integrated, possibly in a projector, and mounted on a vehicle in normal operating mode. It is recalled that the module is arranged, once mounted in the projector and then in the vehicle, and as shown in the following figures, so that its optical axis is contained in a substantially horizontal plane (substantially, because the module can be adjusted, in fact, so that its optical axis is slightly inclined, especially downwards, less than 2 °).

Similarly, throughout the present text, "length" means a dimension measured along the optical axis, "width" is a dimension measured horizontally perpendicular to the optical axis, and "height" is a dimension measured vertically perpendicular to the optical axis. optical axis

For example, on figures 1 , 2 and 7 at 11C , the "front" is on the right, and the "back" on the left, and on the Figures 10A and 10B , D _top is the length of the F _top face of the folder, and W _top is the width of the same F _top face.

With reference to the figure 1 schematically in longitudinal section a module according to the prior art, of the elliptical kind, comprising, arranged on an optical axis X, a reflector R of the ellipsoidal genus receiving a light source S, and a lens L convex plane type . The module is here a module intended to emit a road beam only. The light source S is of any suitable type. In this case, it is a halogen lamp. The source S is at the first focus of the reflector R. The convergent lens L has a focus substantially coincident with the second focus of the reflector R.

The light rays r1, r2, r3, r4 emitted by the light source S are sent towards the lens L either directly or after reflection on the wall of the reflector R. The rays emerging from the lens L then form a light beam. The rays represented in dotted lines are the average radii passing through the second focus of the reflector.

Here, since it is a question of making a road beam, there is no concealing element of type cache able to make a break. However, is represented, in known manner, a static cover Cs which is a frame for delimiting with clarity and precision the shape of the unbroken beam.

The figure 2 is a longitudinal section of a modified elliptical road module according to the invention (in all the figures, the same references represent the same components). The only modification with respect to the module according to the preceding figure is the presence of an additional optical element, the folder P, in the vicinity of the second focus of the reflector R. This folder consists of a block B of transparent material, of parallelepiped shape , oriented perpendicularly to the optical axis X in a substantially vertical plane. Its upper face, about 14 mm wide and about 2 to 10 mm long, especially 2 to 5 mm long, and preferably 3 or 5 mm long, is covered with a reflective coating Re, which is here a deposit of aluminum, vacuum deposited from a thickness of less than one micron to tens of microns. Its upper face is located on the optical axis X of the module, or in its vicinity, being preferably located under the optical axis X, for example about 2 mm below the optical axis X.

The paths of the four limit radii r'1, r'2, r'3 and r'4 have changed: the radius r'1 reaches the coating Re coming from the lower part of the reflector, it is deflected down and then returned in the lens to contribute to the lower part of the beam. The radius r'2 successively crosses the two side walls of the glass block B: it emerges from B in the same orientation with which it had entered. The radius r'4 strikes the reflective coating Re coming from the upper part of the reflector R: it is deflected upwards before passing through the lens L and contributing to the upper part of the beam. The radius r'3 passes over the folder P and is not affected.

The figure 3 is an isolux of the road beam obtained with the module according to the prior art of the figure 1 : Its maximum illumination is 113 Lux at 25 meters, for a total flow of 1616 lumen. The maximum iso illumination curve Cmax represented on the figure 3 corresponds to a level of 64 Lux.

The figure 4 is an isolux of the module according to the invention of the figure 2 . Its maximum illumination is 170 Lux at 25 meters for a total flow of 1610 lumens. The maximum illumination iso curve Cmax 'represented on the figure 4 corresponds to a level of 128 Lux.

It is deduced from the comparison of these values that the maximum intensity of the beam according to the invention is increased by 50% without significant loss of flux.

The folder therefore has a very beneficial effect on the maximum light intensity values of a road beam. And this advantage is much greater than the slight loss of induced flux (which is due in particular to the fact that there are losses in r'2 type rays, which pass through the glass block, and the losses also suffered by the rays deviated by the reflective coating, which is not 100% reflective but also a little absorbent).

The figure 5 shows a variant of folder according to the invention: the wall "most downstream" of the block B relative to the optical axis X of the module is provided in the lower part of a coating B1 opacifier. This coating can replace, in the lower part, the static cover Cs mentioned above. It can also make it possible to improve or to adjust more precisely the light distribution of the beam.

The figure 6 shows a second module variant according to the invention: the only difference with the variant according to the figure 2 is the fact that here the light source S is not a filament lamp but a light-emitting diode, whose emitting surface is turned in the opposite direction to that of the optical axis X: the rays emitted in a half-plane are reflected by the reflector, then some of them, either coming from above or from below, are deflected by the folder according to the same principle as figure 2 . Here, therefore, there is no direct light emitted by the source that can reach the folder or the lens, but only indirect light, already reflected by the reflector R.

The Figures 7, 8 and 9 relate to a third module variant according to the invention: a bi-function module code / route. Relative to figures 2 and 6 there are two differences. On the one hand, here the source is a xenon lamp. The fact that this lamp emits a light with different characteristics at the top and bottom explain that the reflector R is a little different, including a lower part "flat" because less useful optically than in previous cases. On the other hand, there is here a mobile cover C, arranged between the folder P and the lens L, in the immediate vicinity of the folder P. The figures show it in different positions.

To the figure 7 , the cache C (which is in fact a double cache, of approximately V-shaped section, as described for example in the patent FR 07 01290 filed on February 22, 2007 ) is in the up position, an optically active position capable of creating, according to the shape of its upper edge, the code-type cut in the beam, in a known manner (it is clear that the cache C can define any other appropriate cutoff profile). The reflecting surface Re of the folder P is in the immediate vicinity of the optical axis of the projector, under the upper edge of the cover C in its optically active position.

• soit tendent à « se perdre » au dessus de la lentille L,
• soit contribuent au renforcement du faisceau.

In the high position, we see the figure 7 that the upper edge of the cache C defining the beam cutoff is above the reflective upper face Re of the folder. Part of the rays that would be deflected upwards by the reflective coating Re is then intercepted by the cover. Those who can pass over the cache:

• either tend to "get lost" above the L lens,
• either contribute to strengthening the beam.

Thus, when the cover C is in the active position, because of its configuration relative to the folder, it renders it partially ineffective optically.

• soit, comme représenté à la figure 8, le cache C est basculé selon un axe de rotation non représenté qui est sensiblement horizontal et perpendiculaire à l'axe optique X,
• soit, comme représenté à la figure 9, le cache C est abaissé, dans un mouvement de translation dans un plan sensiblement vertical et perpendiculaire à l'axe optique X.

The Figures 8 and 9 represent two possibilities of retracted position, optically passive of the cache:

• either, as shown in figure 8 , the cover C is pivoted along an axis of rotation, not shown, which is substantially horizontal and perpendicular to the optical axis X,
• either, as shown in figure 9 , the cover C is lowered, in a translation movement in a substantially vertical plane and perpendicular to the optical axis X.

In both cases, in this retracted position, it no longer plays a significant optical role, it can no longer create a cutoff: a road-type beam is obtained.

Note that in this variant of dual function module, the folder according to the invention is static, and is not secured to the cache, although in its immediate vicinity, in front of it.

The movement of the cover is achieved by any appropriate means, in particular with the aid of an electric motor controlled by a control panel or automatically, or by any appropriate manual means.

Also, the bi-function module can be coupled with an automatic switching device from one type of beam to another, such as that described in the patent. FR 2,877,892 .

• F_in pour la face arrière par laquelle la lumière pénètre dans la plieuse P,
• F_out pour la face avant par laquelle émerge la lumière,
• F_top pour la face supérieure pourvue du revêtement réfléchissant Re,
• F_bottom pour la face inférieure opposée à la face F_top,
• F_right et F_left pour les faces latérales de la plieuse P.

avec les conventions suivantes :

• W_top est la largeur de la face supérieure F_top, mesurée perpendiculairement à l'axe optique X,
• W_bottom est la largeur de la face inférieure F_bottom, mesurée perpendiculairement à l'axe optique X,
• D_top est la longueur de la face supérieure F_top, mesurée parallèlement à l'axe optique X, et représentant l'épaisseur de la plieuse P,
• L'axe Z est un axe perpendiculaire à l'axe optique X,
• α_in est l'angle que forme la face d'entrée F_in avec l'axe Z, et
• α_out est l'angle que forme la face de sortie F_out avec l'axe Z.

We have shown on Figures 10A to 11C different embodiments of the folder according to the invention. To simplify the description of these variants, the faces of the folder P have been designated by:

• F _in for the rear face through which the light enters the folder P,
• F _out for the front side through which emerges the light,
• F _top for the upper side provided with the reflective coating Re,
• F _bottom for the _bottom face opposite the F _top face,
• F _right and F _left for the side faces of the folder P.

with the following conventions:

• W _top is the width of the top face F _top , measured perpendicularly to the optical axis X,
• W _bottom is the width of the bottom face F _bottom , measured perpendicular to the optical axis X,
• D _top is the length of the top face F _top , measured parallel to the optical axis X, and representing the thickness of the folder P,
• The Z axis is an axis perpendicular to the optical axis X,
• α _in is the angle formed by the input face F _in with the axis Z, and
• α _out is the angle formed by the output face F _out with the Z axis.

The Z axis is a vertical axis, or slightly inclined to the vertical in the case of a slight inclination of the optical axis X relative to the horizontal due to a range correction performed on the module once in place on the vehicle.

We see on Figures 10A and 10B that at least one of the front faces F _in or rear F _out of the transparent block constituting the folder P can be inclined relative to to the Z axis. More precisely, the rear face F _in can be inclined towards the rear of the angle α _in , and the front face F _out can be inclined towards the front of the angle α _out .

The angles α _in and α _out formed respectively by the rear faces F _in and before F _out with the Z axis are advantageously between 5 ° and 30 °, the angle α _in being less than or equal to the angle α _out .

In an embodiment shown on the Figures 10A, 10B and 11A for example, the angles α _in and α _out equal to each other and to the value 17 ° are chosen, the angles α _in and α _out being measured from the Z axis.

In this embodiment, the folder P therefore constitutes a transparent block symmetrical with respect to the axis Z, hexahedron-shaped. The upper face F _top of this volume has for example a width W _top of about 6 mm, and a length D _top of between 2 mm and 10 mm, and preferably equal to about 5 mm.

The rear faces F _in and front F _out being inclined in this way, the length of the lower face F _bottom of the folder P is lower than that D _top of the upper face F _top . The folder P then behaves like a deviating prism. In this way, some of the rays passing through the transparent block constituting the folder may be deviated to improve the quality and / or homogeneity of the light beam leaving the module.

It has thus been observed that, by using a transparent block with sides parallel to each other and vertical, as shown in FIG. figure 2 and 5 at 9 In the beam, it was possible to have the appearance of rays surmounting the main concentration light spot, also called "hot spot", thus creating a secondary concentration spot dissociated from the main spot and which could appear as uncomfortable for the driver .

By appropriately tilting at least one of the rear faces F _in or before F _out of the transparent block, as represented in particular on the Figures 10A, 10B and 11A it is possible for these rays, forming a spot above the "hot spot", to be deflected downwards, and to merge with the "hot spot": a more homogeneous road beam is obtained which is more pleasant for the driver .

This is what we see on the figure 12 , which represents an isolux of the module according to the embodiment of the invention on the Figures 10A and 10B . The maximum illumination is 163 Lux at 25 meters for a total flow of 1610 lumens. The curve iso maximum illumination Cmax "shown on the figure 12 corresponds to a level of 128 Lux.

We deduce from the comparison of these values with those of the figure 3 that the maximum intensity of the beam according to the invention is increased by 44%, without significant loss of flux.

The inclination of the faces F _in and F _out of the folder therefore has a very beneficial effect on the maximum light intensity values of a road beam.

The same effect can be obtained with angles α _in between the input face F _in and the Z axis, and α _out between the output face F _out and the unequal axis Z, preferably choosing α _in lower or equal to α _out .

Alternatively, at least one of the rear faces F _in and before F _out of the transparent block may be curved, in particular at least partially concave, as has been represented on the figure 11C .

According to yet another embodiment, the angle α _out that the output face F _out forms with the Z axis is greater than the angle α _in which the input face F _in forms with the Z axis. can for example provide that αin = 5 ° and αout = 20 °. Indeed, it has been found that it is the inclination of the front face F _out of the transparent block which is the most effective for deflecting the spokes in a controlled manner, and that the rear face F _in can therefore have a smaller inclination, or even just be in a vertical plane as in the first embodiment of the figures 2 and 5 at 9 .

The figure 11C still represents an alternative embodiment of the transparent block constituting the folder P, in which the rear end and front end are this time curved: they are both concave, with a radius of curvature of about 35mm. Preferably, their radius of curvature is between 20 and 50 mm, in particular between 30 and 40 mm. It can also be provided that only the front face F _out is concave, and that the rear face F _in remains flat, in a vertical or inclined plane. The appropriate curvature of a face or faces of the transparent block makes it possible to deviate the rays in a controlled manner, as explained above.

Variants and other modes of construction are still possible.

For example, it is possible for the lateral faces F _left and F _right not to be parallel, but to make an angle with the axis Z. Preferably, the lateral faces F _left and F _right will have the same inclination, so that that the block transparent retains symmetry with respect to a vertical plane passing through the optical axis X.

For example, it is possible to provide that the width W _bottom of the _bottom face F _bottom is greater than or equal to width W _top of the _top face F _top , taking for example values W _top = about 6 mm, and W _bottom = about 14 mm.

Such a design has the advantage of not introducing a lack of homogeneity on the sides of the beam: one notices in fact on the figure 4 that a transparent parallelepipedic block such as B whose upper face has a width extending over substantially the entire width of the module transversely to the optical axis generates defects of homogeneity on the beam. More precisely, as can be seen on the figure 4 , the different isolux each have a "throttle" on either side of the optical axis X, just above the horizontal, for values of the opening angle of about 30%.

Such "hollows" in the side of the beam are visible in the presence of obstacles on the sides of the road and therefore present discomfort for the driver. In its preferred embodiment, shown in Figures 10A and 10B , the transparent block has an upper face whose width W _top is restricted with respect to the total width of the system and reduced with respect to the width W _bottom of the lower face, its main vocation being to act locally only in the vicinity of the zone of maximum concentration. It can be seen that the lateral defects described above no longer appear on the isoluxes of the figure 12 .

Claims (19)

Optical module (M) for a motor vehicle lighting device comprising a reflector (R) defining an optical axis (X), a dioptric element (L), a light source (S) arranged between the reflector and the dioptric element, - A folder (P) disposed between the source and the dioptric element and having a transparent block (B) whose upper face (F _top ) is provided at least partially with a reflective coating (Re). Module according to the preceding claim, characterized in that it is intended to emit at least one road-type uninterrupted beam, the upper face (F _top ) of the folder (P) deflecting upwards at least some of the rays emitted by the source and / or reflected by the reflector (R) to increase the maximum intensity of said beam. Module according to one of the preceding claims, characterized in that the transparent block (B) is arranged substantially perpendicularly to the optical axis (X) of the module (M), symmetrically with respect to this axis (X). Module according to the preceding claim, characterized in that at least a portion of at least one of the right (F _right ), left (F _left ), front (F _in ) or rear (F _out ) side walls of the transparent block ( B) is made opaque, or diffusing, in particular by local metallization (B1) or by frosting or by association with an occulting element. Module according to one of the preceding claims, characterized in that the transparent block (B) has right (F _right ), left (F _left ), front (F _in ) or rear (F _out ) side walls parallel to one another, or at least one of these walls (F _right , F _left , F _in , F _out ) which is curved. Module according to one of Claims 1 to 4, characterized in that the transparent block (B) is in the form of a hexahedron whose volume is delimited by two parallel rectangular faces (F _top , F _bottom ) and four lateral faces, front and rear trapezoidal (F _in , F _left , F _out , F _right ). Module according to Claim 6, characterized in that at least one of the faces (F _top , F _bottom , F _in , F _left , F _out , F _right ) of the hexahedron is curved, convex or concave. Module according to one of the preceding claims, characterized in that the parallel rectangular faces (F _top , F _bottom ) are parallel to the optical axis (X). Module according to Claim 6, characterized in that at least one of the front or rear faces (F _in , F _out ) is inclined with respect to the perpendicular (Z) to the optical axis (X) by an angle of between 5 ° and 30 °. Module according to the preceding claim, characterized in that the front or rear faces (F _in , F _out ) are inclined relative to the perpendicular (Z) to the optical axis (X) by an angle equal to 17 °. Module according to claim 6, characterized in that the lateral faces (F _left , F _right ) are inclined with respect to the perpendicular (Z) to the optical axis (X), the width (W _top ) of the upper face ( F _top ) being less than or equal to the width (W _bottom ) of the bottom face (F _bottom ). Module according to one of the preceding claims, characterized in that the transparent block (B) has an upper edge (Bs) plane or at least curved locally. Module according to one of the preceding claims, characterized in that it also comprises a cover (C) arranged between the folder (P) and the dioptric element (L). Module according to the preceding claim, characterized in that the cover (C) is movably mounted between at least one optically active position and a retracted position. Module according to the preceding claim, characterized in that the optically active position of the cover (C) corresponds to the emission by the module of a cut-off beam, in particular of the code type, and in that its retracted position corresponds to the emission by the module of an unbroken beam, particularly of the road type. Module according to the preceding claim, characterized in that the cover (C) makes the folder (P) at least partially optically inefficient when it is in the optically active position. Module according to one of the preceding claims 14 to 16, characterized in that the cover (C) has, in the optically active position, its upper edge at a height such as that of the upper face (F _top ) of the block ( B) of the folder (P) that it intercepts a part of the rays reflected by the upper face of the reflective coating (Re) thereof. Module according to one of the preceding claims, characterized in that the light source (S) is a filament lamp or a xenon-type arc lamp or a light-emitting diode or a group of light-emitting diodes. Headlight for a motor vehicle, characterized in that it comprises an optical module (M) according to any one of the preceding claims.

Images