EP1528312A1 - Lighting module for vehicle headlamp - Google Patents

Abstract

The module has reflectors (3, 4) each comprising an optical axis passing through a focus (F2) of a reflector (2) and perpendicular to an optical axis of the reflector (2). A folder (5) arranged between the reflectors (3, 4) has an upper reflecting surface (10) carrying the optical axis of the reflectors (3, 4). The surface permits to fold images of light source (6) reflected by elliptical surface (7) of the reflector (2) to the focus.

Description

The present invention relates to a lighting module for vehicle headlamp producing a cut-off type lighting beam particularly suitable for use with diodes emitting.

A beam of cut-off lighting means a beam lighting that has a directional limit or cutoff, above which the emitted light intensity is low.

The low beam and fog lamp functions are examples of cut-off light beams, in accordance with the European legislation in force.

Generally, in an elliptical projector, the cut is made by means of a cover, which is formed of a vertical plate of adapted profile, which is interposed axially between the elliptical reflector and the lens convergent, and which is arranged in the vicinity of the second focus of the reflector.

The cache allows to hide the light rays from the source bright and reflected by the reflector towards the lower part of the focal plane of the convergent lens, and which would be, in the absence of a cache, issued by the projector above the cut.

However, such a solution presents certain difficulties.

Thus, a disadvantage of this type of projector is that a part significant light flux emitted by the source dissipates in the face back of the cache.

Another solution is to make a lighting module using a light source and a Fresnel optic or a reflector type complex surface. To create a break, it is necessary to align the edges of the light source images on the measurement screen used to validate the regulation lighting beam.

This solution also poses certain problems.

So when the light source is a diode, it is very difficult to make a clean cut. Indeed, the image of the virtual source corresponding to the diode is usually round is diffuse and it is much more complicated to make a clean cut by aligning the corresponding images of round shapes.

This difficulty can be overcome by using a diaphragm with the diode, but then we lose a significant amount of light energy produced by the diode.

In addition, the emission indicators of the most known diodes performance are complex and achieving a homogeneous beam is very difficult to obtain from the direct images of the diode.

The present invention aims to provide a lighting module for vehicle headlamp producing a cut-off type lighting beam to achieve a clean cut, including using a diode as a light source, as well as a homogeneous lighting beam while offering less loss of luminous flux by avoiding the use of a cache.

un premier réflecteur comportant une surface de réflexion des rayons lumineux, dont la coupe dans un plan est une ellipse

au moins une source lumineuse agencée au voisinage du premier foyer dudit premier réflecteur,

   caractérisé en ce que ledit module comporte :

un deuxième réflecteur produisant une première partie du faisceau à coupure et ayant un axe optique passant par le second foyer dudit premier réflecteur,

un troisième réflecteur produisant une deuxième partie du faisceau à coupure et ayant un axe optique passant par le second foyer dudit premier réflecteur,

un quatrième réflecteur, dit plieuse, agencé entre ledit deuxième réflecteur et ledit troisième réflecteur et comportant :

un bord, dit bord de coupure, agencé au voisinage dudit second foyer dudit premier réflecteur de manière à former la coupure dans le faisceau d'éclairage,

une face supérieure réfléchissante incluant lesdits axes optiques respectifs desdits deuxième et troisième réflecteur.

The present invention proposes for this purpose a lighting module for a vehicle headlight producing a lighting beam of the cut-off type comprising:

a first reflector comprising a reflection surface of the light rays, the section of which in a plane is an ellipse

at least one light source arranged in the vicinity of the first focus of said first reflector,

characterized in that said module comprises:

a second reflector producing a first portion of the cut-off beam and having an optical axis passing through the second focus of said first reflector,

a third reflector producing a second portion of the cut-off beam and having an optical axis passing through the second focus of said first reflector,

a fourth reflector, called a bender, arranged between said second reflector and said third reflector and comprising:

an edge, said cutting edge, arranged in the vicinity of said second focus of said first reflector so as to form the cut in the lighting beam,

a reflective upper face including said respective optical axes of said second and third reflectors.

Thanks to the invention, the majority of the luminous flux emitted by the source is used in the light beam produced by the module.

In addition, the lighting module according to the invention makes it possible to a clean cut, especially with a diode because it projects to the front the image of the cutoff edge. The shape of the cut in the beam lighting is therefore determined by the profile of the cutting edge.

Another advantage of the module according to the invention is that it operates a property of elliptical lighting modules which is to "mix" the images of the light source at the second focus of the first reflector, which improves the homogeneity of the lighting beam produced.

In addition, such a module has optical performance improved compared to a system using a lens; there is indeed less losses due to non-unit reflection coefficient of surfaces reflective of the second and third reflectors that by reflections glassy in the lens.

Finally, according to the configuration of the invention, the first reflector and its light source may be concealed behind one of the said second or third reflector so the user looking at the output beam do not see the first reflector. Such a solution allows, for example, get rid of the use of a mask to hide the first reflector and its light source.

Advantageously, the optical axes of said second and third reflectors are merged.

Advantageously, said first reflector is arranged at the back of said second reflector so that said first reflector is concealed by said second reflector

Advantageously, said second reflector and said third reflector have a focus arranged in the vicinity of said second focus of said first reflector.

According to an advantageous embodiment, said second reflector and / or said third reflector comprise a reflection surface of luminous rays whose cut in a plane is a parabola.

According to another advantageous embodiment, said second reflector and / or said third reflector are a surface-type reflector reflection complex of light rays.

In a particularly advantageous manner, said light source is a light emitting diode.

In a particularly advantageous manner, said cutting edge is a beveled edge defining an oblique surface, said oblique surface being determined so that said cutoff edge does not intercept the rays reflected by said first reflector and passing beyond said second focus.

Advantageously, said second focus of said first reflector is located at the center of the portion of line intersecting between said surface oblique and said reflective upper face of said folder.

Advantageously, according to a first solution, said first and third reflectors are made of a single piece and / or said second and fourth reflectors are made in one piece.

Advantageously, according to a second solution, said second, third and fourth reflectors are made in one piece.

According to a very advantageous embodiment, the lighting module has a fifth reflector receiving direct light rays from said first light source, the reflecting surface of said fifth reflector being such that it produces a third part of the breaking beam.

Advantageously, according to a first solution, said first, third and fifth reflectors are made in one piece.

Advantageously, according to a second solution, said first and Fifth reflectors are made in one piece.

un réflecteur dit sans coupure produisant ledit deuxième faisceau d'éclairage sans coupure et ayant un axe optique passant par le second foyer dudit premier réflecteur et perpendiculaire à l'axe optique dudit premier réflecteur,

une deuxième source lumineuse agencée au voisinage du foyer dudit réflecteur sans coupure.

Advantageously, the lighting module produces a second unlighted lighting beam and comprises:

an uninterrupted reflector producing said second unbreakable illumination beam and having an optical axis passing through the second focus of said first reflector and perpendicular to the optical axis of said first reflector,

a second light source arranged in the vicinity of the focus of said unbroken reflector.

According to this last embodiment, the reflective surface of said unbroken reflector can be a substantially paraboloidal surface to which a reduction factor is applied in one direction perpendicular to the optical axis of said first reflector and to the optical axis said sixth reflector.

According to this last embodiment, said unbroken reflector can be a type reflector with a complex reflection surface luminous.

un cinquième réflecteur symétrique dudit premier réflecteur par rapport au plan de la face supérieure réfléchissante de ladite plieuse,

une deuxième source lumineuse agencée au voisinage du premier foyer dudit cinquième réflecteur.

According to another embodiment, the lighting module comprises:

a fifth reflector symmetrical of said first reflector with respect to the plane of the reflective upper face of said folder,

a second light source arranged in the vicinity of the first focus of said fifth reflector.

Advantageously, according to this last embodiment, said edge cutoff is a beveled edge defining an oblique surface, said oblique surface being determined so that said cutting edge does not intercept the rays reflected by said first reflector and passing beyond said second focus, said oblique surface being reflective and receiving a portion of the light rays from said fifth reflector and said module comprises a sixth reflector receiving the light rays from said oblique surface, said sixth reflector having a surface substantially paraboloidal reflection of light rays with a focus arranged in the vicinity of said second focus of said first reflector.

Advantageously, according to this last embodiment, said module has a seventh reflector receiving directly the light rays from said second light source and having a surface substantially paraboloidal reflection of light rays.

In a particularly advantageous manner, said folder comprises a corrective surface of the field curvature located along said edge of cut and in the continuity of said upper face of said folder of so that no ray from said first reflector and returned to said third reflector does not exceed said cut.

Said corrective surface may be a surface that absorbs the light or reflecting surface and inclined at an angle determined by relative to the plane of said reflective upper face of said bender of so that the rays coming from said first reflector and which would have been returned above the cut in the absence of said corrective surface are entirely reflected in a direction opposite to the direction of the said first cut-off lighting beam.

In a variant, the first reflector consists of an ellipso-parabolic surface. In this case, it is advantageous to provide that the second reflector and / or the third reflector is a parabolic cylinder.

• le premier réflecteur collecteur comporte une surface de réflexion des rayons lumineux dont la coupe dans un plan est une ellipse,
• au moins une première source lumineuse est agencée au voisinage du premier foyer dudit réflecteur,

   ledit module comportant :

• un réflecteur de sortie produisant un faisceau à coupure et ayant un axe optique passant par le second foyer dudit premier réflecteur et perpendiculaire à l'axe optique dudit premier réflecteur,
• un réflecteur dit plieuse, agencé entre ledit premier réflecteur collecteur et ledit réflecteur de sortie comportant :
  • un bord, dit bord de coupure, agencé au voisinage dudit second foyer dudit premier réflecteur de manière à former la coupure dans le faisceau d'éclairage,
  • une face supérieure réfléchissante incluant ledit axe optique du premier réflecteur collecteur.

According to another variant,

• the first collector reflector comprises a reflection surface of light rays whose section in a plane is an ellipse,
• at least one first light source is arranged in the vicinity of the first focus of said reflector,

said module comprising:

• an output reflector producing a cut-off beam and having an optical axis passing through the second focus of said first reflector and perpendicular to the optical axis of said first reflector,
• a so-called bending reflector arranged between said first collector reflector and said output reflector comprising:
  • an edge, said cutting edge, arranged in the vicinity of said second focus of said first reflector so as to form the cut in the lighting beam,
  • a reflective upper face including said optical axis of the first collector reflector.

It is then advantageous to provide that the first collector reflector consists of an ellipso-parabolic surface, and / or that the third exit reflector is a parabolic cylinder.

Other features and advantages of the present invention will appear in the following description of embodiments of the invention, given by way of illustration and in no way limitative.

La figure 1 représente schématiquement une vue de coté d'un module d'éclairement selon un premier mode de réalisation de l'invention illustrant le trajet des rayons lumineux,

La figure 2 représente schématiquement une vue de coté d'un module d'éclairement selon un deuxième mode de réalisation de l'invention et illustrant le trajet de certains rayons lumineux,

La figure 3 représente schématiquement une vue de coté d'un module d'éclairement selon un troisième mode de réalisation de l'invention,

La figure 4 représente schématiquement une vue de coté d'un module d'éclairement selon un quatrième mode de réalisation de l'invention,

La figure 5 représente une courbe d'isophote d'un module d'éclairement tel que représenté en figure 1 avec un bord de coupure sans correction de courbure de champ,

La figure 6 représente une surface correctrice de courbure de champ utilisé dans un module tel que représenté en figure 1,

La figure 7 représente une courbe d'isophote d'un module d'éclairement tel que représenté en figure 1 avec un bord de coupure corrigé avec la surface représentée en figure 6,

La figure 8 représente une courbe d'isophote d'une variante de module d'éclairement tel que représenté en figure 1 avec des surfaces réfléchissantes modifiées.

La figure 9 représente une variante du mode de réalisation de la figure 1.

In the following figures:

FIG. 1 schematically represents a side view of an illumination module according to a first embodiment of the invention illustrating the path of the light rays,

FIG. 2 schematically represents a side view of an illumination module according to a second embodiment of the invention and illustrating the path of certain light rays,

FIG. 3 schematically represents a side view of an illumination module according to a third embodiment of the invention,

FIG. 4 schematically represents a side view of an illumination module according to a fourth embodiment of the invention,

FIG. 5 represents an isophote curve of an illumination module as represented in FIG. 1 with a cutoff edge without field curvature correction,

FIG. 6 represents a correction surface of field curvature used in a module as represented in FIG. 1,

FIG. 7 represents an isophote curve of an illumination module as represented in FIG. 1 with a cutoff edge corrected with the surface represented in FIG. 6,

FIG. 8 represents an isophote curve of a variant of illumination module as represented in FIG. 1 with modified reflecting surfaces.

FIG. 9 represents a variant of the embodiment of FIG. 1.

In all the figures, the common elements bear the same reference numbers.

FIG. 1 schematically represents a side view of a lighting module 1 for a vehicle headlamp according to a first mode of embodiment of the invention.

un premier réflecteur 2,

un deuxième réflecteur 3,

un troisième réflecteur 4,

un quatrième réflecteur 5,

une source lumineuse 6.

Module 1 comprises:

a first reflector 2,

a second reflector 3,

a third reflector 4,

a fourth reflector 5,

a light source 6.

deux foyers F1 et F2,

un axe optique A2,

une surface réfléchissante 7 sensiblement elliptique.

The first reflector 2 is an elliptical reflector having:

two foci F1 and F2,

an optical axis A2,

a substantially elliptical reflecting surface 7.

The substantially elliptical reflective surface 7 is made under the shape of a substantially angular sector of revolution and that extends into the half-space above a perpendicular axial plane at the plane of the sheet and containing the optical axis A2. First approximation, the surface 7 is a half-ellipsoid.

It can be noted, however, that surface 7 may not be perfectly elliptical and have several specific profiles planned for optimize the light distribution in the lighting beam produced by the module 1. This implies that the first reflector 2 is not perfectly of revolution.

The light source 6 is arranged substantially at the first F1 focus of the first reflector 2.

Advantageously, the light source 6 is a diode electroluminescent light which emits the majority of its light energy towards the reflective inner surface of the substantially elliptical surface 7.

This diode 6 is for example a diode made of nitride gallium GaN with a phosphor for emitting white light.

un foyer sensiblement confondu avec le second foyer F2 du premier réflecteur 2,

un axe optique A1,

une surface réfléchissante 8.

The second reflector 3 comprises:

a focus substantially coincident with the second focus F2 of the first reflector 2,

an optical axis A1,

a reflective surface 8.

The optical axis A1 is substantially parallel to the longitudinal axis of a vehicle not shown and equipped with the lighting module 1 and forms an angle equal to 90 ° with the optical axis A2.

The reflecting surface 8 is of substantially paraboloidal shape, the axis of the parabola being the optical axis A1.

un foyer sensiblement confondu avec le second foyer F2 du premier réflecteur 2,

un axe optique A1 identique à celui du deuxième réflecteur 3,

une surface réfléchissante 9.

The third reflector 4 comprises:

a focus substantially coincident with the second focus F2 of the first reflector 2,

an optical axis A1 identical to that of the second reflector 3,

a reflecting surface 9.

Let Y be the same direction and in the same direction as the optical axis A2, a direction Z identical and opposite direction to the optical axis A1 and a direction X so that the XYZ center mark F2 forms a direct reference.

The third reflector 4 is then substantially the symmetrical of the second reflector 3 with respect to the plane (F2, X, Z). Note, however, that the symmetrical character of the second and third reflectors 3 and 4 is optional.

The fourth reflector 5, also called a folder, lies between the second reflector 3 and the third reflector 4 and comprises at least one reflective upper face and a front end edge 11, said edge of cut.

The cutting edge 11 is arranged in the vicinity of the second focus F2 of the first reflector 2.

The operating principle of module 1 is as follows:

We will consider for this reason three light rays R1, R2 and R3 from the light source 6.

Since the light source 6 is arranged at the first focus F1 of the first reflector 2, most of the rays emitted by the source 6, after reflected on the inner face 7, is returned to the second focus F2 or in the vicinity of it. This is the case of the radius R1 which passes along the edge 11. R1 is then reflected on the surface 9 of the third reflector 4 in a direction substantially parallel to the optical axis A1 of the third reflector 4. Note here that the cutting edge 11 has a bevel 12 defining an oblique surface. This oblique surface 12 is determined from so that the cutting edge 11 is not likely to intercept rays reflected by the first reflector 2 and passing beyond the second focus F2.

Other rays may, after being reflected on the inner face 7, reflect on the surface 10 of the folder 5; this is the case of R2. R2 is going then think again about the paraboloidal surface 8 of the second reflector 3 and this reflection will be down in the plane of Figure 1. The radius R2 is thus emitted under the cut-off in the lighting beam. Without the reflection of R2 on the surface 10, the radius R2 would have reflected on the surface 9 of the third reflector 4 and would have been unacceptable (because above of the cut).

Other rays, of the R3 type, can pass beyond the edge 11. In such a case, the ray R3 is then reflected on the surface 9 of the third reflector 4 and is also reemitted under the cut in the beam lighting.

The reflective surface 10 makes it possible to "fold" the images of the light source 6 which are reflected by the elliptical surface 7 of the first reflector 2 at the second focus F2.

The "fold" formed by this "folding" of images helps to form a clear cut in the lighting beam reflected by the second and third reflectors 3 and 4.

The first reflector 2 is located behind the second reflector 3 of so that, when looking at the face module (facing the optical axis A1), we does not see the first reflector 2 and the light source 6; these are hidden by the second reflector and it is unnecessary to provide hiding place.

Note that we considered that the second and third reflectors are perfectly symmetrical, so with the same optical axis A1; they may not be symmetrical and have optical axes different, the only condition being that their optical axes intersect at second focus F2 of the first reflector and belong to the same plane (F2, X, Z).

Note also that the rear face 13 of the folder 5 can be reflective for construction reasons but this part reflective will not be used.

FIG. 2 schematically represents a side view of a 100 lighting module for vehicle headlamp according to a second mode embodiment of the invention.

This module 100 is identical to module 1 of FIG. difference that it further comprises a fifth reflector 14.

This fifth reflector has a reflecting surface 15 which receives light rays directly from the light source 6 and produces a beam of light rays below the horizontal cut. If the light source 6 was punctual and without any optical device surrounding it, the reflective surface 15 would be a paraboloidal surface with a focus located at the second focus F2 of the first reflector.

In practice, the light source 6 such as a diode electroluminescent is not a point source and has a chip not shown as a square or rectangular surface surrounded by a half-lens spherical plastic not shown and centered on the center of the chip. Therefore, the non-punctualities of the source and the lens must be taken into consideration for the construction of the reflecting surface 15.

Without a lens but with only a non-point source, a complex surface can be used to achieve the reflective surface.

When the source is not only punctual but includes also a spherical lens, one solution is to build the reflective surface from a source considered as point and from point 17 of the square of the chip closest to the fifth reflector 14.

The reflective surface 15 is then constructed so that the radius R5 from point 17 is parallel to the optical axis A1. Construction can be do this by considering the spherical wave surface from point 17 which is then transformed into a non-spherical wave surface via its passage by the half-plastic lens. This non-spherical wave surface can to be determined by the laws of Descartes. We build the surface reflecting 15 so as to obtain a corresponding plane wave surface at a plane parallel to the optical axis A1 after reflection on the surface reflecting 15 of the non-spherical wavefront previously determined. His equation is obtained by writing the constancy of the path optical along a ray from point 17 to a plane perpendicular to the axis optically (this plane can be chosen arbitrarily but must be identical for all the radii considered).

Once the reflective surface has been determined, since the point 17 is the closest point to that surface 15, the other such rays that the radius R6 coming from the point 18 farthest from the surface 15 is give rise to a radius below the cutoff after reflection on the surface 15.

This fifth reflector 14 makes it possible to increase significantly the intensity of the cut-off beam by recovering the light that would be, in the absence of this fifth reflector 14, lost towards the rear of the module 100.

Note that the first, third and fifth reflectors respectively 2, 4 and 14 can be made in one piece with a simple mold without drawer in a standard plastic material of the PPS type (Phenylene polysulfide). It is the same for the second reflector 3 5. In both cases, the reflective coating does not have to be only on one side since there are optical surfaces reflective than on one side.

Note also that the fifth reflector can occupy a reduced space under the first reflector 2 and leave a free zone 16 between said first and fifth reflectors into which can be inserted an optical device for performing an additional function such as the realization of an unbroken beam such as daytime running lights or traffic lights DRL daytime running light (English).

FIG. 3 schematically represents a side view of a lighting module 101 for a vehicle headlamp according to a third mode embodiment of the invention.

un réflecteur 18 dit sans coupure,

une deuxième source de lumière 20.

This module 101 is identical to module 1 of FIG. 1 with the difference that it further comprises:

a reflector 18 said without cut,

a second light source 20.

This reflector 18 without cutoff has a reflective surface interior 19 substantially paraboloidal with an optical axis confused with the optical axis A1 of the second and third reflectors 3 and 4 and a focus F3.

This focus F3 is positioned positively along the axis F2-Z and the Light source 20 is arranged in the vicinity of said focus F3.

If the reflective surface 19 of the unbroken reflector 18 was a real parable, it would produce a seamless output beam substantially circular. But regulators impose the uninterrupted functions of the road or DRL type to have a beam that is about twice as wide as it is high, i.e. the beam should spread twice more next X than following Y.

Therefore, if we want to add a second function of the type without module 101 which complies with the regulatory standards, it is necessary to adapt the reflecting surface 19.

One solution is to apply a reduction factor adapted according to X to paraboloid 19. This transformation can be realized in known manner by optical optimization software of the CODE V type.

Another solution consists in producing a complex surface for the reflective surface 19 by adding streaks on the surface as described in the documents FR2760068 and FR2760067.

FIG. 4 schematically represents a side view of a 102 lighting module for a vehicle headlamp according to a fourth mode embodiment of the invention.

un cinquième réflecteur 21,

une deuxième source de lumière 27,

un sixième réflecteur 23,

un septième réflecteur 25.

This module 102 is identical to module 1 of FIG. 1 with the difference that it further comprises:

a fifth reflector 21,

a second light source 27,

a sixth reflector 23,

a seventh reflector 25.

The fifth reflector 21 is substantially the symmetrical of the first reflector 2 with respect to the plane (F2, X, Z). From then on, the first focus F4 of this fifth reflector 21 is the symmetrical focus F1 of the first reflector 2 relative to the second focus F2 of the first reflector 2 and the second focus of the fifth reflector is merged with the second reflector F2 of the first reflector 2.

The second light source is substantially arranged at the neighborhood of the first focus F4 of the fifth reflector

The reflective surface 22 of the fifth reflector 21 is therefore substantially elliptical with an optical axis A3 directed in the opposite direction to the optical axis A2.

The bevel 12 of the folder is made reflective so that it can reflect some of the reflected rays on the reflective surface 22 of the fifth reflector 21.

The sixth reflector 23 receives the light rays coming from the bevel 12 reflective, said sixth reflector 23 having a surface substantially paraboloidal reflection of light rays with a fireplace arranged at near the second focus F2 of the first reflector 2.

The seventh reflector 25 has a reflective surface 26 substantially paraboloidal that produces a beam of light rays above and below the horizontal cut. Reflective surface 26 has a focus located at the second focus F2 of the first reflector and is arranged in order to directly receive light from the second source 27 and which is not reflected on the surface 22 of the fifth reflector 21.

The operating principle of module 102 is as follows:

We will consider for this reason four light rays R7, R8, R9 and R10 from the second light source 27.

Since the second light source 27 is arranged at the first F4 focus of the fifth reflector 21, most of the rays emitted by the source 27, after being reflected on the inner face 22, is returned to the second focus F2 or in the vicinity thereof. This is the case of the R7 ray which passes along the cutoff edge 11. R7 is then reflected on the surface 8 of the second reflector 3 in a direction substantially parallel to the axis A1 optical reflector of the second reflector 3.

Other rays may, after being reflected on the inner face 22, reflect on the reflective bevel 12 of the folder 5; this is the case of R9. R9 will then reflect again on the paraboloidal surface 24 of the sixth reflector 23 and this reflection will be upwards in the plane of the Fig. The radius R9 is thus emitted above the cut in the beam lighting. This is because the radius R9 comes from a point below cutting edge 11.

Other rays, of the R8 type, can pass beyond the edge 11. In such a case, the ray R8 is then reflected on the surface 8 of the second reflector 3 and is also re-emitted above the cutoff in the lighting beam.

Finally, the R10 type rays that are not intercepted by the surface 22 of the fifth reflector are emitted towards the surface 26 of the seventh reflector 25 and then transmitted in a beam above and below the cut. The ray R10 represented as reflecting in the center of the surface 26 is exactly on the cut. However, it is possible to construct the surface 26 so that it produces a beam at cut. This construction would be done for example in the same way as the construction of the reflector 14 of Figure 2 by inverting the beams.

Note here that if both light sources 6 and 27 are lit at the same time we obtain an output beam of the high beam type or DRL; when the first source 6 is only lit, we always have a cut-beam of the dipped beam or fog lamp type. The module 102 thus makes it possible to create a complementary beam by adding light above the cutoff line of the main beam.

Note also that another arrangement is to rotate the sixth and seventh reflectors 23 and 25 of a positive angle (1 ° in our realization) around, respectively, the X axis of the marker and an axis parallel through the second light source 27, so as to provide an overlap between the complementary beam and the beam (the maximum intensity of the sum is then higher and there is no more risk of creating a line of contrast between the two beams).

FIG. 5 represents a curve 200 of an isophot of the module illumination 102 as shown in Figure 1 with a cut edge right along the X axis.

The curve 200 shows that a part comprising two fins 201 and 202 of the lighting beam is above the directional limit or cutoff separating the illuminated surface into two zones I (unbroken) and II (above the cut).

The presence of fins 201 and 202 in zone II is due to the absence of field curvature correction, especially after reflection on the third reflector 4. Thus, in theory, all the rays arriving on the reflecting surface 9 and passing along the cutting edge 11 should start again horizontally. In practice, apart from the paraxial approximation, the image projected by the paraboloid 9 is never equally sharp for points on either side of F2 focus according to direction X and slightly offset on the Z axis. The image of these points is found over the cut and explains the presence of the fins 201 and 202.

Therefore, it is necessary to make a curvature correction of field. One solution is to prevent light from passing through the dots likely to provide a beam above the horizontal. We add then an opaque corrective surface at the cutoff edge 11 that will prevent the rays coming from the surface 7 and likely to be troublesome to reach the surface 9 of the third reflector 4. Such a surface determined by standard software simulation means is then contiguous to the cutting edge 11 and has substantially the shape of the part hatched under the fins 201 and 202 in the plane (F2, X, Z).

However, such an opaque surface can be difficult to achieve because it is necessary, during the metallization operations of the reflecting surface 10 of the folder 5, save on a small area with a sharp edge after said reflecting surface 10.

It is therefore desirable to simply add a surface corrector at the edge 11, said corrective surface remaining reflective for reasons of simplicity of manufacture.

However, we can not keep the same corrective surface as described above since the rays intended for the surface 9 and hidden by the reflective corrective surface will then reflect to the surface 8 of the second reflector 3 to provide a beam above the cutoff, thereby displacing the problem of non-correction of field curvature to the second reflector 3. A solution to this problem is illustrated in figure 6.

FIG. 6 represents a reflective corrective surface 400 of field curvature used in a module as shown in Figure 1.

1^ère condition : elle empêche les rayons provenant de la surface 7 et susceptibles d'être au-dessus de la coupure d'atteindre la surface 9 du troisième réflecteur 4.

2^ème condition : elle appartient à un plan P contenant l'axe F2-X et incliné d'un angle prédéterminé, ici 20°, par rapport au plan (F2, X, Z) de sorte que les rayons gênants bloqués par la surface 400 soient réfléchis vers l'arrière du module 1 et en aucun cas vers la surface réfléchissante 8 du deuxième réflecteur 3.

This surface 400 is in the extension of the cut-off edge 11 and is calculated using a standard simulation software so as to fulfill the following two conditions:

1 provided ^era: it prevents the rays from the surface 7 and may be above the cut to reach the surface 9 of the third reflector 4.

^2nd condition: it belongs to a plane P containing the axis F2-X and inclined by a predetermined angle, here 20 °, with respect to the plane (F2, X, Z) so that the annoying rays blocked by the surface 400 are reflected towards the rear of the module 1 and in no case towards the reflecting surface 8 of the second reflector 3.

FIG. 7 represents an isophote curve 300 of a module of illumination as shown in FIG. 4 with a corrected cut edge with the surface 400 in the plane P as shown in FIG.

Curve 300 shows that the entire lighting beam is below directional limit or cut, i.e. in zone I.

The field correction surface 400 has been described with reference to the Figure 1 but it is clear that it also applies to other modes of embodiment of Figures 2 to 4.

In all the embodiments of FIGS. 1 to 4, a second solution to avoid the fins such as 201 and 202 can be found in a slight modification of the reflective surfaces of the first reflector 2 and second and third reflectors 3 and 4.

• en référence à la figure 1 :
  • que la surface 7 du premier réflecteur 2 pouvait ne pas être parfaitement elliptique et avoir d'autres profils spécifiques pour optimiser la répartition lumineuse dans le faisceau d'éclairage produit par le module 1, et que ceci impliquait que le premier réflecteur 2 ne devait pas être parfaitement de révolution,
  • que les surfaces réfléchissantes 8 et 9 du deuxième 3 et du troisième réflecteur 4 étaient de forme sensiblement paraboloïdales, et
• en référence à la Figure 5,
  • que la présence des ailettes 201 et 202 dans la zone Il était due à l'absence de correction de courbure de champ notamment après réflexion sur le troisième réflecteur 4.

We noted above:

• with reference to Figure 1:
  • that the surface 7 of the first reflector 2 may not be perfectly elliptical and have other specific profiles to optimize the light distribution in the light beam produced by the module 1, and that this implied that the first reflector 2 should not to be perfectly revolutionary,
  • that the reflecting surfaces 8 and 9 of the second 3 and the third reflector 4 were substantially paraboloidal in shape, and
• with reference to Figure 5,
  • that the presence of the fins 201 and 202 in the zone II was due to the absence of field curvature correction in particular after reflection on the third reflector 4.

We can therefore use these remarks to modify slightly the surfaces of the first, second and third reflectors for get a correction of the field curvature, and thus eliminate the fins 201 and 202 in the beam emitted by one of the lighting modules 1, 100, 101 or 102 described above.

Such a correction of the curvature of the field must result in not send light rays above the cutoff separating the surface illuminated in two zones, that is to say do not send rays in the zone II of Figure 7. Under these conditions, the directional limit between zones I and It can be considered as the infinite image of the cut edge 11 of the fourth reflector 5 formed by the second and third reflectors 3 and 4.

The invention therefore consists in using a straight cutting edge 11, and to form the image at infinity using the second and third reflectors 3 and 4, these being constituted by parabolic cylinders, that is to say surfaces such as 8 or 9 in Figure 1, generated by a line segment perpendicular to the plane of this figure and resting on parable 8 or 9.

The first reflector 2 must therefore be a transforming surface the spherical wave emitted by the light source 6 into a cylindrical wave, whose generator is parallel to the cutting edge 11.

• une coupe de ce réflecteur par un plan horizontal est une parabole, et
• la coupe dans un plan vertical contenant la source lumineuse est une ellipse.

The surface of the first reflector 2 is then easily constructed, and thus an ellipso-parabolic surface is obtained:

• a section of this reflector by a horizontal plane is a parabola, and
• the section in a vertical plane containing the light source is an ellipse.

Thus, by producing a lighting module, including the first reflector 2 consists of an ellipso-parabolic surface, of which the second and third reflectors 3 and 4 are parabolic cylinders, and the fourth reflector 5 or folder has a cutting edge 11 rectilinear the beam emitted by such a lighting module presents the isophote curve 400 shown in Figure 8.

Curve 400 shows that the entire illumination beam emitted by the lighting module just described is below the limit directional or cutoff, i.e. in zone I.

So we see that we get a beam whose cut is particularly clean and rectilinear, with a simple folder, that is to say, of which the edge is straight, and therefore very easy to achieve.

Such a design makes it possible to design a second variant of the lighting module according to the present invention, more particularly shown in Figure 9.

According to this variant, in module 103, the first and third reflectors are such as those just described, the second reflector is removed, and the reflector is arranged so that that its reflective face includes the optical axis A2 of the first collecting reflector 2.

Nous considérons pour cela encore trois rayons lumineux R1, R2 et R3 issus de la source lumineuse 6.

The operating principle of the module 103 is deduced from the foregoing:

We consider for this purpose three light rays R1, R2 and R3 coming from the light source 6.

Since the light source 6 is arranged at the first focus F1 of the first reflector collector 2, most of the rays emitted by the source 6, after being reflected on the inner face 7, is returned to the second focus F2 or in the vicinity thereof. This is the case of the radius R1 which passes along the cutting edge 11, R1 is then reflected on the surface 9 of the output reflector 4 in a direction substantially parallel to the axis A1 optical output reflector 4. Note here that the cut edge 11 has a bevel 12 defining an oblique surface. This oblique surface 12 is determined so that the cut edge 11 is not at risk to intercept rays reflected by the first reflector 2 and passing beyond the second focus F2.

Other rays may, after being reflected on the inner face 7, reflect on the surface 10 of the folder 5; this is the case of R2. R2 is going then reflect again on the paraboloidal surface 9 of the reflector of exit 4 and this reflection will be down in the plane of Figure 9. The radius R2 is thus emitted under the cut-off in the lighting beam.

Other rays, of the R3 type, can pass beyond the edge 11. In such a case, the ray R3 is then reflected on the surface 9 of the reflector of output 4 and is also reemitted under the cut in the beam lighting.

The reflective surface 10 makes it possible to "fold" the images of the light source 6 which are reflected by the elliptical surface 7 of the first reflector 2 at the second focus F2.

The "fold" formed by this "folding" of images helps to form a clear cut in the lighting beam reflected by the reflector of exit 4.

In order to collect the maximum of light rays emitted by the light source 6, the first collector reflector 2 can extend up to the optical axis A1 of the output reflector 4, as shown in Figure 9.

Of course, the invention is not limited to the embodiments which have just been described.

Claims (29)

A vehicle headlight lighting module (1) providing a first cut-off type lighting beam comprising: a first reflector (2) having a surface (7) for reflecting light rays whose section in a plane is an ellipse, at least a first light source (6) arranged in the vicinity of the first focus (F1) of said first reflector (2), characterized in that said module (1) comprises: a second reflector (3) producing a first portion of the cut-off beam and having an optical axis (A1) passing through the second focus (F2) of said first reflector (2) and perpendicular to the optical axis (A1) of said first reflector ( 2) a third reflector (4) producing a second portion of the cut-off beam and having an optical axis (A1) passing through the second focus (F2) of said first reflector (2) and perpendicular to the optical axis (A1) of said first reflector ( 2) a fourth reflector (5), called a bender, arranged between said second reflector (3) and said third reflector (4) and comprising: o an edge (11), said cutting edge, arranged in the vicinity of said second focus (F2) of said first reflector (2) so as to form the cut in the lighting beam, a reflective upper face (10) including said respective optical axes (A1) of said second and third reflectors (3, 4). Module (1) lighting according to claim 1 characterized in that said optical axes (A1) of said second and third reflectors (3, 4) are merged. Lighting module (1) according to one of claims 1 or 2 characterized in that said first reflector (2) is arranged at the rear of said second reflector (3) so that said first reflector (2) is concealed by said second reflector (3). Module (1) lighting according to one of claims 1 to 3 characterized in that said second reflector (3) and said third reflector (4) have a focus (F2) arranged in the vicinity of said second focus (F2) of said first reflector (2). Module (1) lighting according to one of claims 1 to 3 characterized in that said second reflector (3) and / or said third reflector (4) comprise a surface (8, 9) of reflection of light rays whose cut in a plane is a parable. Module (1) lighting according to one of claims 1 or 2 characterized in that said second reflector (3) and / or said third reflector (4) are a reflector of type complex surface reflection of light rays. Module (1) lighting according to one of the preceding claims characterized in that said light source (6) is a light emitting diode. Lighting module (1) according to one of the preceding claims characterized in that said cutting edge (11) is a beveled edge defining an oblique surface (12), said oblique surface (12) being determined so that said edge cutoff (11) does not intercept the rays reflected by said first reflector (2) and passing beyond said second focus (F2). Module (1) lighting according to the preceding claim characterized in that said second focus (F2) of said first reflector (2) is at the center of the intersection line portion between said oblique surface (12) and said upper face (10). reflective of said folder (5). Lighting module (1) according to one of the preceding claims, characterized in that said first and third reflectors (2, 4) are made in one piece and / or said second and fourth reflectors (3, 5) are made in one piece. Module (1) lighting according to one of the preceding claims characterized in that said second, third and fourth reflector (3, 4, 5) are made in one piece. Lighting module (100) according to one of the preceding claims characterized in that it comprises a fifth reflector (14) directly receiving light rays from said first light source (6), the reflecting surface (15) of said fifth reflector (14) being such as to produce a third portion of the cut-off beam. Lighting module (100) according to claim 12 characterized in that said first, third and fifth reflectors (2, 4, 14) are made in one piece. Lighting module (100) according to claim 12 characterized in that said first and fifth reflectors (2, 14) are made in one piece. Lighting module (101) according to one of claims 1 to 14 providing a second unbreakable lighting beam characterized in that it comprises: a so-called unbroken reflector (18) producing said second unbreakable illumination beam and having an optical axis (A1) passing through the second focus (F2) of said first reflector (2) and perpendicular to the optical axis (A1) of said first reflector (2), a second light source (20) arranged in the vicinity of the focus (F3) of said reflector (18) without interruption. Lighting module (101) according to the preceding claim characterized in that the reflective surface (19) of said reflector (18) without cut is a substantially paraboloidal surface to which a reduction factor is applied in a direction perpendicular to the optical axis (A2) of said first reflector (2) and to the optical axis (A1) of said unbroken reflector (18). Lighting module (101) according to claim 15, characterized in that said unbroken reflector (18) is a reflector of the complex surface type of reflection of light rays. Lighting module (102) according to one of Claims 1 to 11, characterized in that it comprises: a fifth reflector (21) symmetrical with said first reflector (2) with respect to the plane of the reflective upper face (10) of said folder (5), a second light source (27) arranged in the vicinity of the first focus (F4) of said fifth reflector (21). Lighting module (102) according to Claim 18, characterized in that : said cutting edge (11) is a bevelled edge defining an oblique surface (12), said oblique surface (12) being determined such that said cutting edge does not intercept the rays reflected by said first reflector (2) and passing beyond said second focus (F2), said oblique surface (12) being reflective and receiving a portion of the light rays from said fifth reflector (21), said module (102) comprises a sixth reflector (23) receiving the light rays coming from said oblique surface (12), said sixth reflector (23) having a substantially paraboloidal surface (24) for reflecting light rays with a fireplace arranged in the vicinity said second focus (F2) of said first reflector (2). Lighting module (102) according to one of claims 18 or 19, characterized in that it comprises a seventh reflector (25) directly receiving the light rays coming from said second light source (27) and having a surface (26) substantially paraboloidal reflection of light rays. Module (1) lighting according to one of the preceding claims characterized in that said folder comprises a surface (400) corrector of the field curvature located along said cutting edge (11) and in the continuity of said upper face (10) of said folder (5) so that no ray from said first reflector (2) and returned to said third reflector (4) exceeds said cut. Module (1) lighting according to the preceding claim characterized in that said corrective surface absorbs light. Lighting module (1) according to claim 21 characterized in that said corrective surface (400) is reflective and is inclined at a given angle with respect to the plane of said reflective upper face (10) of said folder so that the rays from said first reflector (3) and which would have been returned above the cut in the absence of said corrective surface are entirely reflected in a direction opposite to the direction of said first lighting beam. Module (1) lighting according to one of claims 1 to 20, characterized in that the first reflector (2) consists of an ellipso-parabolic surface. Module (1) lighting according to the preceding claim, characterized in that the second reflector (3) is a parabolic cylinder. Lighting module (1) according to claim 24 or claim 25, characterized in that the third reflector (4) is a parabolic cylinder. A vehicle headlamp lighting module providing a cut-off type lighting beam comprising: a first collector reflector (2) having a surface (7) for reflecting light rays whose section in a plane is an ellipse, at least a first light source (6) arranged in the vicinity of the first focus (F1) of said first reflector (2), characterized in that said module comprises: an output reflector (4) producing a cut-off beam and having an optical axis (A1) passing through the second focus (F2) of said first reflector (2) and perpendicular to the optical axis (A2) of said first reflector (2) . A reflector (5), called a bender, arranged between said first collector reflector (2) and said output reflector (4) and comprising: o An edge (11) called cutting edge, arranged in the vicinity of said second focus (F2) of said reflector (2) so as to form the cut in the lighting beam, a reflective upper face (10) including said optical axis (A2) of the first collector reflector (2). Lighting module according to claim 27, characterized in that the first reflector (2) consists of an ellipso-parabolic surface. Lighting module according to claim 27 or claim 28,
characterized in that the third output reflector (4) is a parabolic cylinder.

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