EP1855051A1 - Optical module of automobile headlight - Google Patents

Abstract

The module has an elliptical type reflector (R) with a light source (E) placed near a focus (F1) of the reflector. A convergent lens (L) admits a focus (FL) near a focus (F2) of the reflector. A light recuperator (A) collects a part of light flow from the source and sends the flow towards the front. An ellipsoid type reflector (6) focuses a part of radiation from the source near a focus which is lower than the focus (FL). The recuperator (A) presents an inlet side (7) near which a focus of the reflector is situated.

Description

• un réflecteur de type elliptique avec au moins une source lumineuse placée au voisinage d'un premier foyer du réflecteur ;
• une lentille convergente placée en avant du réflecteur et admettant un foyer situé au voisinage du deuxième foyer du réflecteur, ou confondu avec.

The invention relates to an optical projector module for a motor vehicle, of the kind comprising those arranged along an optical axis:

• an elliptical type reflector with at least one light source placed in the vicinity of a first focus of the reflector;
• a convergent lens placed in front of the reflector and admitting a focus located in the vicinity of the second focus of the reflector, or coincident with.

A projector may be composed of one or more optical modules, similar or different.

In such a light projector module, part of the luminous flux emitted by the source is lost. It has therefore been sought to improve the performance of optical systems of the elliptical type, in particular with xenon or halogen source, with a significant light input in areas of the beam that require this input.

JP 2003 338210 proposes to improve the performance of the elliptical technique by using a light recuperator able to collect a part of the light flux directed downwards from the source and to return it towards the front of the vehicle.

However, the piece of transparent material, glass or plastic, constituting the light recuperator according to JP 2003 338210 has a large size not compatible with industrial molding conditions, and making it difficult to install this piece in a bright projector. The entrance to the room has a fresnelized shape to collimate the rays, and the size of this entrance is important. As a result, it becomes difficult to modify the beam, for example for an AFS application, by masking this area because it is necessary to hide a large area.

The collimation of the spokes and the guarantee of obtaining a cut in the beam require a perfect adjustment of the position of the part with respect to the source, which makes complex the mechanical realization of the system.

The object of the invention is, above all, to provide an elliptical type projector module in which light recovery is improved and efficiency increased, in a simple way as to the realization.

• un réflecteur de type ellipsoïde (6) est prévu en avant , en partie supérieure du module, ce réflecteur (6) focalisant une partie des rayons issus de la source (E) au voisinage d'un second foyer (µ₂) situé en avant, plus bas que le foyer (FL) de la lentille (L),
• et le récupérateur de lumière présente un bord à proximité du deuxième foyer du miroir elliptique, constituant le bord de coupure.

According to the invention, a projector optical module for a vehicle of the kind defined above which comprises, in the lower part, a light recuperator able to collect a part of the flow of the source (in particular pointing downwards), and to send it forward, is such that:

• an ellipsoid-type reflector (6) is provided in front, in the upper part of the module, this reflector (6) focusing part of the rays coming from the source (E) in the vicinity of a second focus (μ ₂ ) located in front , lower than the focus (FL) of the lens (L),
• and the light recuperator has an edge near the second focus of the elliptical mirror, constituting the cutoff edge.

An "ellipsoid-type" reflector is understood to mean a reflector substantially of ellipsoidal shape or whose behavior is close to / similar to that of an ellipsoidal reflector. It is the same for the reflector "elliptical type". "Up" or "down" are terms to be understood for the module in the configuration it has in the projector in mounting position in the vehicle.

Advantageously, the upper front portion of the elliptical reflector is stopped at an area corresponding to the extreme rays which, after reflection on the reflector, are collected as boundary rays by the lens.

Preferably, the recuperator is monoblock in transparent material. The recuperator has an input face inclined on the optical axis of the projector, having an upper limit which forms the cutoff edge.

The input face of the recuperator is arranged so that the rays reflected by the ellipsoid type reflector and falling on this input face are substantially deviated. This input face is preferably substantially flat.

The recuperator can be limited in the lower part by an inclined surface, in particular an inclined plane, working in total reflection, the spokes being straightened by the recuperator to, in particular, - on average - be substantially parallel to the optical axis of the face of output of the recuperator.

Advantageously, the output face of the recuperator is of revolution around the optical axis. The exit face may admit, as meridian vertical section, an elliptical arc whose focus is the image, given by the inclined plane, of the second focus of the ellipsoid-type reflector, to give an emergent beam admitting a plane wave surface. substantially orthogonal to the optical axis

According to another possibility, the exit face of the recuperator admits as horizontal section that of a given quadric to give a cylindrical output wave plane with substantially vertical generatrices.

The light projector module can have a mobile cover at the input face of the recuperator, this cover can be placed in an erased position where it lets the light to the input face, or occupy a position in which it hides the light.

The module can be mounted movably and the recuperator can be fixed and placed so that in the projector's rest position the light coming from the additional ellipsoid type reflector passes next to the recuperator, while in the functional position, the projector comes position yourself next to the recuperator, which becomes active.

The light projector module may include a cover located between the reflector and the lens, bounded by an end edge forming a cutoff edge, located in the vicinity of the focus of the lens.

The recuperator may comprise an inlet face inclined on the optical axis and whose upper limit is formed by an edge which passes through the focus of the system formed by a plane mirror and the diopter of the exit face.

The recovered beam may be an uninterrupted beam, the recuperator having an entrance face inclined on the optical axis and whose upper limit is formed by an edge not passing through the focus of the ellipsoid reflector or the focus of the system constituted by the plane mirror and the diopter of the exit face.

According to another possibility, the recovered beam is a variable beam, the recuperator having an input face inclined on the optical axis, with a movable cover in front of the face.

• Fig. 1 est une coupe schématique verticale passant par l'axe optique d'un projecteur selon l'invention.
• Fig. 2 est une vue schématique suivant la flèche II de Fig. 1.
• Fig. 3 est une coupe schématique verticale à plus grande échelle du récupérateur selon l'invention.
• Fig.4 est une vue en projection horizontale de la transformation d'une surface d'onde sphérique en une surface d'onde plane par le récupérateur de Fig. 3.
• Fig.5 est une coupe schématique par un plan horizontal d'une variante du récupérateur de Fig. 3 pour l'obtention d'un faisceau élargi.
• Fig. 6 est une projection horizontale illustrant le faisceau à surface d'onde cylindrique obtenu avec le récupérateur de Fig. 5.
• Fig. 7 est une coupe verticale schématique d'une variante du récupérateur de Fig. 3.
• Fig. 8 est une représentation schématique du réseau de courbes isolux obtenu avec le récupérateur de Fig. 3.
• Fig.9 est une représentation schématique d'un autre réseau de courbes isolux obtenu avec le récupérateur de Fig.5, et
• Fig. 10 est une vue schématique en plan d'un projecteur DBL selon l'invention.

The invention consists, apart from the arrangements described above, in a certain number of other arrangements which will be more explicitly discussed hereinafter with regard to exemplary embodiments described with reference to the appended drawings, but which are not in no way limiting. On these drawings:

• Fig. 1 is a vertical schematic section through the optical axis of a projector according to the invention.
• Fig. 2 is a schematic view along arrow II of FIG. 1.
• Fig. 3 is a schematic vertical section on a larger scale of the recuperator according to the invention.
• FIG. 4 is a horizontal projection view of the transformation of a spherical wave surface into a plane wave surface by the recuperator of FIG. 3.
• Fig.5 is a schematic section through a horizontal plane of a variant of the recuperator of FIG. 3 to obtain an enlarged beam.
• Fig. 6 is a horizontal projection illustrating the surface beam cylindrical wave obtained with the recuperator of FIG. 5.
• Fig. 7 is a schematic vertical section of a variant of the recuperator of FIG. 3.
• Fig. 8 is a schematic representation of the network of isolux curves obtained with the recuperator of FIG. 3.
• FIG. 9 is a schematic representation of another isolux curve network obtained with the recuperator of FIG.
• Fig. 10 is a schematic plan view of a DBL projector according to the invention.

Referring to Fig. 1 of the drawings, there can be seen schematically a light projector module 1 which comprises, along its optical axis YY, a reflector R of elliptical type with at least one light source E placed in the vicinity of a first focus F1, or internal hearth reflector, whose second focus F2, or external focus, is located further forward. The terms "front" and "rear" are to be understood by considering the direction of propagation of the light which, according to FIG. 1, go from left to right.

A convergent lens L is placed in front of the reflector R and admits a focus FL coincides with the second focus F2, or located in the vicinity of this second focus of the reflector.

A cover 2 is located between the reflector R and the lens L. In the example shown in FIG. 1 the cache 2 is formed by a screen orthogonal to the normally horizontal Y-Y optical axis. The cover 2, located in a vertical plane, is limited in the upper part by an upper edge 2a, forming a cutting edge, located in the vicinity of the focus FL of the lens L, or through this focus.

Alternatively, the vertical cover 2 could be replaced by a horizontal folder ensuring the cutting of the beam.

A light recuperator A is provided in the lower part of the lens L to collect a portion of the flow from the source E, directed downwards and to return it forward.

• soit le réflecteur R est calculé pour entraîner les rayons réfléchis à passer à proximité du cache 2 et du foyer FL : dans ce cas, les rayons lumineux sortent de la lentille ;
• soit le réflecteur R est calculé pour faire rentrer les rayons dans la lentille ; dans ce cas les rayons lumineux passent par le haut du cache 2 et sont rabattus fortement vers le bas après passage dans la lentille. Ils provoquent alors un excès de lumière proche ou pire des parasites lorsque des rayons sortant de la lentille avec un fort rabattement rencontrent des pièces de style aluminiées du projecteur.

The upper part 3 of the reflector R beyond a zone 4 loses its effectiveness. Indeed :

• either the reflector R is calculated to cause the reflected rays to pass close to the cover 2 and the focus FL: in this case, the light rays emerge from the lens;
• either the reflector R is calculated to fit the rays into the lens; in this case the light rays pass through the top of the cover 2 and are folded down strongly after passing through the lens. They then cause an excess of light near or worse parasites when rays coming out of the lens with a strong drawdown encounter aluminized style parts of the projector.

In practice, zone 4 is defined by a plane orthogonal to the Y-Y axis adjacent to a point such as 5 of the reflector. The point 5 is such that it returns a light ray i1, from the focus F1, along a reflected ray r1 which arrives on the lower edge of the lens L. The rays coming from the source E and falling on the reflector R in points in front of point 5 will be reflected according to rays issuing from the lens L.

It should be noted that the source E is extended and that the reflector R is not necessarily focused in the center of the source. The "limit" rays pass at the edge of the lens and must be folded by a sufficient angle (about fifteen degrees) after exit of the lens. This condition uniquely determines the passage of the limit radius in the cache plane at a point Δ.

• soit passent au-dessus du point Δ et ont alors une chance de rentrer dans la lentille, mais ils sont rabattus d'un angle supérieur à 15° et sont donc inutiles ;
• soit passent sous le point Δ, auquel cas ils sortent de la lentille.

Lighting beams having a thickness of 10 ° to 15 ° maximum, all radii in front of zone 4:

• either pass over the point Δ and then have a chance to enter the lens, but they are folded by an angle greater than 15 ° and are therefore useless;
• either pass under the point Δ, in which case they come out of the lens.

According to the invention, the upper part 3 of the reflector R is cut in the vicinity of the zone 4 and is extended by an ellipsoid type reflector 6, which is simplified by "elliptical mirror", which has a first focus μ1 in the vicinity of the light source E, and a second focal point μ2 located in front, lower than the optical axis YY, and the focus FL of the lens L. The second focus μ2 can be almost at the same vertical level as the lower edge of the lens L, without this being necessary.

The mirror 6 focuses the light rays it receives from the source E to the focal point μ2 located between the lens L and the reflector R.

The light recuperator A is made of a transparent material, glass or plastic material such as polymethacrylate. It is arranged at the bottom of the lens and has an edge 7a, orthogonal to the plane of FIG. 1 which passes through the second focus μ2 of the mirror 6.

• soit un faisceau sans coupure, auquel cas le bord 7a ne passe pas par le foyer µ2 ou par le foyer du système constitué par le miroir 8 et le dioptre S1;
• soit un faisceau variable , en ayant un cache mobile 10 devant la face 7 : le cache peut être soit dans une position où toute la face 7 est masquée, et on ne récupère rien; soit dans une position où le bord du cache passe par µ2, on récupère alors un faisceau à coupure : soit dans une position où une large partie de la face 7 est libre au-delà de µ2, on a alors un faisceau sans coupure.

The recuperator A is monobloc and has an inlet face 7 designed so that the light rays reflected by the mirror 6 and falling on this face 7 are little or no deflected entering the recuperator A. This face 7 is substantially flat and, for example, substantially orthogonal to the average direction of the beam from the mirror 6. The input face 7 is inclined on the optical axis YY and its upper limit forms the edge 7a which passes by the focus of the system consisting of the inclined plane 8 and the output face S1, which will be described later. This configuration is necessary to perform an additional cut-off function. However, the invention encompasses the different cases where the recovered beam is:

• or an unbroken beam, in which case the edge 7a does not pass through the focal point μ2 or the focus of the system constituted by the mirror 8 and the diopter S1;
• or a variable beam, having a movable cover 10 in front of the face 7: the cover can be either in a position where the entire face 7 is hidden, and nothing is recovered; either in a position where the edge of the cache passes through μ2, then recovering a cut-off beam: either in a position where a large part of the face 7 is free beyond μ2, then we have an unbroken beam.

The lower part of the recuperator A is bounded by an inclined plane 8 from the rear to the front. The inclination of this plane is provided to ensure total reflection of the rays coming from the mirror 6 and which have entered the recuperator A. The rays are straightened by the recuperator A to - on average - be parallel to the optical axis of the mirror. exit face of the recuperator.

This output face can take many forms and be defined by several equations.

In a first case, it may be desired that any light beam from the focus μ2 emerges parallel to the optical axis Y1-Y1 of the recuperator A, parallel to the optical axis Y-Y. The output face S1 must therefore be of revolution around the optical axis Y1-Y1. The rays reflected by the inclined plane 8 seem to come from a point μ'2 (FIG. 3) which is the image of μ2 given by the plane mirror 8. The exit face S1 focuses all the rays that are virtually derived from μ '. 2. Any ray resulting from μ2, and therefore virtually from μ'2, starts in the axis parallel to Y1-Y1. The output face S1 thus transforms a spherical wave surface from μ'2 into a plane wave surface P, orthogonal to the optical axis Y1-Y1, as shown in horizontal projection in FIG.

In Fig. FIG. 3 shows two light rays j1, j2 coming from the focus μ2 which, after reflection on the inclined plane 8 and refraction while crossing the exit face S1, exit along radii e1 and e2 parallel to Y1-Y1.

Considering a reference trirectangle trihedron according to which the x-axis is perpendicular to the plane of FIG. 3, the y-axis is horizontal and the z-axis is vertical, and by writing the constancy of the optical path between focal point μ2 and a plane wave surface P, orthogonal to Y1-Y1, we obtain the given relations hereinafter n being equal to the refractive index of the material of the recuperator A.

avec P1 intersection de l'axe optique Y1-Y1 et de la surface d'onde plane P , et H intersection du rayon sortant par M avec la surface P. For any point M on the surface S1: $$\mathrm{not}\times \stackrel{~}{{\mathit{\mu \text{'}}}_{2}M}+\widetilde{\mathit{MH}}=\stackrel{~}{{\mathit{<figure-callout\; id="1"\; label="OP"\; filenames="imgf0001.png"\; state="\{\{state\}\}">OP</figure-callout>}}_1}+\mathrm{not}\times \stackrel{~}{{\mathit{\mu \text{'}}}_{2}O}$$

with P1 intersection of the optical axis Y1-Y1 and the plane wave surface P, and H intersection of the outgoing ray by M with the surface P.

(xM, yM et zM étant les coordonnées suivant Ox, Oy et Oz du point M).On the one hand by choosing P1 coincides with O, the top of the surface S1, and by writing that μ ' ₂ O = f, and on the other hand, by taking the origin of the reference in O, it comes: $$\mathrm{not}\mathrm{\times }\sqrt{\mathrm{(}\mathrm{uM}\mathrm{-}\mathrm{f}{\mathrm{)}}^{\mathrm{2}}\mathrm{+}{\mathrm{zM}}^{\mathrm{2}}\mathrm{+}{\mathrm{xM}}^{\mathrm{2}}}\mathrm{+}\mathrm{uM}\mathrm{=}\mathrm{not}\mathrm{\times }\mathrm{f}$$

(xM, yM and zM being the coordinates along Ox, Oy and Oz of the point M).

This is the equation of an ellipsoid of which one of the foci is none other than μ'2.

When the elliptical mirror 6 which extends the reflector R is a perfect ellipsoid, the input illumination of the recuperator A is highly focused, in particular along the edge 7a perpendicular to the plane of FIG. 1 and 3. The exit surface S1 focuses all the rays, which leads to a beam of parallel rays e1, e2 very concentrated in width. Such a width concentration may not be desirable.

To widen the beam leaving the face S1, it is possible to envisage widening the spot at the inlet 7a of the recuperator A. Such a solution is however not desirable because, on the one hand, the recuperator becomes larger and, from on the other hand, the light losses are greater because of the curvature of the output face S1.

The invention proposes an advantageous solution consisting in designing an exit face S2 (FIG.5) which makes it possible to retain the vertical deflection properties of the surface S1 of FIGS. 1 and 3, while widening the beam in the horizontal planes.

The surface S2 is determined so that the wave surface P a _is no longer flat, as in the case of FIG. 3 and 4, but cylindrical with vertical generators.

The paths of the light rays in a vertical plane are identical to the representation of FIG. 3. On the other hand, in a horizontal plane corresponds to the top view of Fig. 5, the trace of the wave surface P _a on the horizontal plane can be considered as a circle whose center is situated at a point F ".The distance p = μ ' ₂ F" then determines the width of the spot, that is to say the angle of opening of the beam in the horizontal plane. The light rays issuing from the face S2 have projections on a horizontal plane such that e3 (FIG.5) orthogonal to the wave surface P _a and thus corresponding to radii of the circle passing through the center F ". illustrates in horizontal projection the wave surface P _a .

If p is weak, the radius of the circle P _a is also small and the extreme rays e 3 are strongly divergent, so that the spot or angle of opening of the beam is wide. If on the contrary p is large, the stain narrows. When p tends to infinity, the exit surface S2 is reduced to the surface S1 of FIG. 3.

• pour tout point M_a appartenant à la surface de sortie S2 : $$\mathrm{n}\times \overline{{\mathit{\mu ʹ}}_2{M}_a}+\stackrel{‾}{{{\mathit{M}}_a\mathit{\hspace{0.17em}}\mathit{H}}_a}=\mathrm{n}\times \overline{{\mathit{\mu ʹ}}_2}{O}_a=\mathrm{n}\mathrm{\times }\mathrm{f}$$
  
  n est l'indice de réfraction de la matière du récupérateur, H_a est l'intersection du rayon sortant par M_a avec la surface P_a et O_a est le sommet de S2. Comme H_a se trouve sur le cylindre de centre F" et de rayon R, les projections sur le plan horizontal de F", de M_a et de H_a appartiennent à une même droite. En désignant par M'_a et H'_a les projections de M_a et H_a sur le plan horizontal, on obtient, en prenant comme origine F" :
• pour tout point Ma appartenant à la surface S2 : $$\overline{M_a^{ʹ}{H}_a^{ʹ}}+\overline{\mathit{Fʺ}{H}_a^{ʹ}}-\overline{\mathit{Fʺ}{M}_a^{ʹ}}=\mathrm{R}\mathrm{-}\sqrt{({\mathit{yM}}_a-p{)}^2+{{\mathit{xM}}_a}^2}$$
  
  M_aH_a peut être remplacé par M'_aH'_a puisque , en sortie de S2, le rayon est calculé pour se retrouver dans un plan horizontal parallèle au plan Oxy, condition pour former la coupure horizontale. Par conséquent les projections M'_aH'_a sur Oxy sont bien égales à M_aH_a . En injectant l'équation (2) dans l'équation (1), on obtient :
• pour tout point Ma appartenant à la surface S2, $$\mathrm{n}\times \overline{{\mathit{\mu ʹ}}_2{M}_a}+\mathrm{R}\mathrm{-}\sqrt{({\mathit{yM}}_a-p{)}^2+{{\mathit{x}\mathit{\hspace{0.17em}}\mathit{M}}_a}^2}=\mathrm{n}\mathrm{\times }\mathrm{f}$$
  
  soit $$\mathrm{n}\times \sqrt{\left({\mathit{yM}}_a^2+{\mathit{xM}}_a^2+{\mathit{zM}}_a^2\right)}+\mathrm{R}\mathrm{-}\sqrt{({\mathit{yM}}_a-p{)}^2+{{\mathit{x}\mathit{\hspace{0.17em}}\mathit{M}}_a}^2}=\mathrm{n}\mathrm{\times }\mathrm{f}$$
  

As for the surface S1 of FIG. 3, we write the equation of the surface S2 while expressing the conservation of the optical path:

• for any point M _a belonging to the exit surface S2: $$\mathrm{not}\times \stackrel{~}{{\mathit{\mu \text{'}}}_2{M}_{\mathrm{at}}}+\stackrel{~}{{{\mathit{M}}_{\mathrm{at}}\mathit{}\mathit{H}}_{\mathrm{at}}}=\mathrm{not}\times \stackrel{~}{{\mathit{\mu \text{'}}}_2}{O}_{\mathrm{at}}=\mathrm{not}\mathrm{\times }\mathrm{f}$$
  
  n is the refractive index of the recuperator material, H _a is the intersection of the outgoing radius by M _a with the surface P _a and O _a is the vertex of S2. As _H from the center of cylinder F "and radius R, the projections on the horizontal plane F" of _M and _H belong to the same straight line. By designating by M ' _a and H' _a the projections of M _a and H _a on the horizontal plane, we obtain, taking as origin F ":
• for any point Ma belonging to surface S2 : $$\widetilde{M_{\mathrm{at}}^{\text{'}}{H}_{\mathrm{at}}^{\text{'}}}+\widetilde{\mathit{F"}{H}_{\mathrm{at}}^{\text{'}}}-\widetilde{\mathit{F"}{M}_{\mathrm{at}}^{\text{'}}}=\mathrm{R}\mathrm{-}\sqrt{({\mathit{uM}}_{\mathrm{at}}-p{)}^2+{{\mathit{xM}}_{\mathrm{at}}}^2}$$
  
  M _a H _a can be replaced by M ' _a H' _a since, at the output of S2, the radius is calculated to be in a horizontal plane parallel to the plane Oxy, a condition for forming the horizontal cut. Therefore the projections M ' _a H' _a on Oxy are well equal to M _a H _a . By injecting equation (2) into equation (1), we obtain:
• for any point Ma belonging to the surface S2, $$\mathrm{not}\times \stackrel{~}{{\mathit{\mu \text{'}}}_2{M}_{\mathrm{at}}}+\mathrm{R}\mathrm{-}\sqrt{({\mathit{uM}}_{\mathrm{at}}-p{)}^2+{{\mathit{x}\mathit{}\mathit{M}}_{\mathrm{at}}}^2}=\mathrm{not}\mathrm{\times }\mathrm{f}$$
  
  is $$\mathrm{not}\times \sqrt{\left({\mathit{uM}}_{\mathrm{at}}^2+{\mathit{xM}}_{\mathrm{at}}^2+{\mathit{zM}}_{\mathrm{at}}^2\right)}+\mathrm{R}\mathrm{-}\sqrt{({\mathit{uM}}_{\mathrm{at}}-p{)}^2+{{\mathit{x}\mathit{}\mathit{M}}_{\mathrm{at}}}^2}=\mathrm{not}\mathrm{\times }\mathrm{f}$$
  

It is a quadric that resolves itself by setting parameters in polar coordinates.

The last element of the recuperator A is the upper part 9 which joins the input face 7 to the output face S1, S2. Note that this upper part is contiguous with the input face 7 at the focal point on the edge 7a. This makes it possible to ensure the formation of a cut in the light beam in two ways.

In a first way, the upper part 9 is coated with a black paint so as to prevent the entry of light rays by this upper part 9. Only the rays passing under the edge 7a and under μ ₂ emerge by S1 or S2 hence the formation of a break.

According to a second way, it is advantageous to overmold the transparent recuperator A with an opaque material on the upper part 9. Such an overmolding process is common and makes it possible to ensure with a good accuracy the position of the occulting part with respect to the recuperator A. In addition, the blackout may also have a mechanical function to ensure the position and the fixing of the recuperator A relative to the light module.

According to another possibility, an upper part 9a (FIG 7) is defined which makes it possible to dispense with a cover while ensuring the desired break.

Concretely, the upper part 9a forms, with the input face 7 of the recuperator, an angle α sufficiently large so that rays such as r4 arriving on the upper face 9a, are deviated strongly, along rays such as j4. The spokes j4 arrive on the lower face 8 either with an incidence which guarantees a total reflection, but with an incidence close to normal. Most of them come out on rays such as q4 that are lost and do not fit in the beam projected forward. A small fraction of a radius j4 can be reflected in v4, it may be necessary to place a cache, to avoid any interference, on the upper part 9a forward, but not necessarily the edge of the face of entry 7.

Fig. 8 illustrates the network of isolux curves obtained on a screen placed at 25 m from the projector in the case where the recuperator A has an exit surface S1 (FIG 3). The isolux curve beam is fairly concentrated in width, almost ± 2 m wide at 25 m, an opening angle of ± 4.5 degrees (arc tangent 2/25 = 4.5 degrees). The beam is on the other hand very thick (vertical dimension). It can be limited in thickness by simply limiting the size of the input face.

In the case of a recuperator A with exit surface S2 (Fig. 5) a larger isolux network (Fig 9) can be obtained without loss of flux with a width of about ± 5 m to 25 m an angular aperture of ± 11 degrees (arc tangent 5/25 = 11 degrees). It is possible to go beyond.

In addition to the formation of the cut, the light recovery obtained by virtue of the invention gives a good flexibility for changing the characteristics of the beam. This can be obtained as explained below.

Either a movable cover 10 is provided (FIG 1), for example rotatably mounted about an axis 11 perpendicular to the plane of FIG. 1, at the input face 7 of the recuperator. The cover 10 may be in an erased position shown in solid lines in FIG. 1 in which it allows the light to pass to the input face 7, or on the contrary occupy the dashed position in which it hides this light.

Either we move the entire module or projector, for example by rotating around a vertical axis. This is what happens when the module is mounted on a rotating plate "dynamic lighting for cornering" or DBL. The recuperator A can then be positioned and dimensioned such that in the rest position of the module, that is to say with the optical axis YY parallel to the longitudinal axis of the vehicle, the light coming from the additional elliptical mirror pass next to the recuperator. By cons in the functional position, when the module on its DBL plate has rotated relative to the longitudinal axis of the vehicle, the module is positioned next to the recuperator A which then becomes active.

Fig. 10 schematically illustrates such an arrangement. Two recuperators A1, A2 are arranged fixed on either side of the optical axis Y-Y of a module or projector movable in rotation about a vertical axis. The straight line joining the first focus F1 of the reflector R and the middle of the edge of each recuperator A1, A2 forms an angle ± β with the optical axis Y-Y when the latter is parallel to the longitudinal axis of the vehicle.

In the position illustrated in FIG. 10, the optical axis YY of the module is parallel to the longitudinal axis of the vehicle and the light from the elliptical mirror 6 Extending the reflector R passes next to each of the recuperators A1, A2 which are therefore inactive.

When the driver steers his wheels, to the right for example to follow a turn, the module rotates and the light from the module will reach the recuperator A1 and this completely when the optical axis Y-Y will have turned by an angle β. The recovery of light provided by the recuperator A1 then improves the illumination on the inside of the turn. The recuperator A2 would intervene for a left turn.

The recuperator A, A1 or A2 according to the invention consists of a reduced-size part which can easily be made of glass or plastic. In addition the realization and the formation of the beam cutoff does not depend on the position of the recuperator with respect to the module, hence a very flexible tolerance on the position of the recuperator.

The additional light flux is obtained without adding additional light source.

The invention provides an original style. The increase in the range of the light beam can be much greater than what is achieved with cache movements in known projectors.

The flexibility of the solution of the invention makes it possible to obtain various forms of isolux networks. A mobile cache such as 10 implements only a very simple mechanical system.

The invention may further be complementary to rotating capping systems. In other words, the invention is perfectly compatible with systems used for bi-function projectors code and route (bi halogen or bi-xenon for example). This allows much higher performance values. The light source may have a transverse or axial configuration with respect to the optical axis of the module.

The examples given for the exit surfaces S1, S2 are not limiting.

The invention makes it possible to obtain a clean cut of the beam, devoid of achromatism, with a recuperator formed of a one-piece piece, which itself manages the cut. The solution of the invention makes it possible in particular to increase the range of a highway searchlight by adding a strip of fine light very far from the vehicle and by removing / decreasing any excess light near.

The luminous flux gain provided by the invention is significant. For example, with a source of the xenon lamp type, for a code beam whose luminous flux is 1,000 lumens is added about 100 lumens according to the invention. As regards illumination, this results in a gain of about 30 lux at 25 m, from about 50 to about 80 lux.

The applications are relatively numerous.

For a motorway projector, the exit face of the recuperator is rather elliptical and the entrance face is relatively narrow. Generally there is a cache 10 that is erased for highway traffic.

The FBL application (Fixed Bending Light) also uses a cache that is erased when the excess illumination is desired.

Alternatively, the recuperator is combined with a dynamic bending light (DBL) and the elliptical module can turn while the recuperator is stationary.

• projecteur bihalogène (code et route) avec la partie récupérateur qui fait un faisceau large et épais ;
• projecteur à filament transverse, qui a l'avantage d'être très efficace, le flux récupéré étant très important.

The invention is also suitable for applications such as:

• bihalogen projector (code and road) with the recuperator part which makes a wide and thick beam;
• transverse filament projector, which has the advantage of being very efficient, the recovered stream being very important.

Claims (16)

Optical projector module for a motor vehicle comprising arranged along an optical axis: a reflector (R) of elliptical type with at least one light source (E) placed in the vicinity of a first focus (F1) of the reflector; - A convergent lens (L) placed in front of the reflector and admitting a focus (FL) located in the vicinity of the second focus (F2) of the reflector, or confused with; - and, in the lower part, a light recuperator (A) able to collect a part of the flow of the source and to send it forward, characterized in that - An ellipsoid type reflector (6) is provided in the upper part of the module, this reflector (6) focusing a portion of the rays from the source (E) in the vicinity of a second focus (μ ₂ ) located in before, lower than the focus (FL) of the lens (L), - And the light recuperator (A) has an input face (7) near which is located the second focus (μ ₂ ) of the ellipsoid type reflector (6). Optical module according to claim 1, characterized in that the upper front part (3) of the elliptical reflector situated above the optical axis is stopped at a zone (4) corresponding to the extreme radii (i1) which, after reflection on the reflector, are collected as boundary rays (r1) by the lens (L). Optical module according to claim 1 or 2, characterized in that the recuperator (A) is a monobloc transparent material. Optical module according to one of claims 1 to 3, characterized in that the recuperator comprises an input face (7) inclined on the optical axis (YY) of the projector, having an upper limit (7a). Optical module according to claim 3 or 4, characterized in that the input face (7) of the recuperator is arranged so that the rays reflected by the ellipsoid-type reflector (6) and falling on this input face (7) are practically not deviated. Optical module according to any one of the preceding claims,
characterized in that the inlet face (7) of the recuperator (A) is substantially flat. Optical module according to any one of the preceding claims, characterized in that the recuperator (A) is limited in the lower part by an inclined surface (8) working in total reflection, the spokes being straightened by the recuperator A for, in particular, on average - Be substantially parallel to the optical axis of the output face (S1, S2) of the recuperator. Optical module according to any one of the preceding claims, characterized in that the output face (S1) of the recuperator is of revolution about the optical axis. Optical module according to Claims 7 and 8, characterized in that the exit face (S1) has an elliptical arc as meridian vertical section, a focus of which is the image (μ ' ₂ ) given by the inclined plane (8) the second focus (μ ₂ ) of the ellipsoid type reflector (6), to give an emerging beam admitting a plane wave surface, substantially orthogonal to the optical axis Optical module according to any one of claims 1 to 7, characterized in that the output face (S2) has as horizontal section that of a given quadric to output a cylindrical wave plane (Pa) generators substantially vertical. Optical module according to any one of the preceding claims, characterized in that it comprises a mobile cover (10) at the inlet face (7) of the recuperator (A), this cover (10) being able to be placed in an erased position where it lets the light pass to the input face (7), or occupy a position in which it hides this light. Optical module according to any one of claims 1 to 10, characterized in that it is mounted movably and the recuperator (A1, A2) is fixed and placed so that in the rest position of the projector, the light coming from the reflector of the ellipsoid type (6) additional passes next to the recuperator, while in the functional position, the projector is positioned next to the recuperator (A1, A2) which then becomes active. Optical module according to any one of the preceding claims, characterized in that it comprises a cover (2) located between the reflector and the lens, bounded by an end edge (2a) forming a cutting edge, situated in the vicinity of the focus (FL) of the lens. Optical module according to claim 7, characterized in that the recuperator (A) has an inlet face (7) inclined on the optical axis and whose upper limit is formed by an edge (7a) which passes through the center of the system formed by the plane mirror (8) and the diopter of the exit face (S1). Optical module according to claim 7, characterized in that the recovered beam is an unbroken beam, the recuperator (A) having an input face (7) inclined on the optical axis and whose upper limit is formed by an edge (7a) not passing through the focus (μ2) of the ellipsoid type reflector (6) or by the focus of the system consisting of the plane mirror (8) and the diopter of the output face (S1). Optical module according to claim 7, characterized in that the recovered beam is a variable beam, the recuperator (A) having an input face (7) inclined on the optical axis, with a movable cover (10) in front of the face (7).

Images