EP1936260B1 - Automobile headlight module for a cut-off beam - Google Patents

Description

The invention relates to a motor vehicle light projector module giving a cut-off beam, this module comprising a concave reflector, a light source disposed in the concavity of the reflector, and a lens located in front of the reflector and the light source. . The source is formed by at least one light emitting diode to illuminate at least upward. The reflector is associated with a folder whose upper surface is reflective to fold the beam from the reflector. The folder has a front end edge that is adapted to form the cut in the lighting beam. The module is such that the exit surface of the lens is selected so that it can be connected in a continuous surface to the exit surfaces of neighboring module lenses.

Licences FR 2,872,257 and FR 2 868 510 and EP 1 610 057 shows lighting modules of this type which make it possible, by juxtaposing the ends of the output lenses, to produce a projector whose exit output surface is continuous, smooth, of toric appearance. However, the average line of the lenses of these projectors is located in a plane, that is to say that the average line extends in two dimensions only, and can not be a left line extending in three dimensions. In addition, these projectors only allow a flat cut in the beam.

The evolution of the style of the vehicles leads to projectors having housings provided with ices whose surface admits a left curve like average line. It is desirable, especially for the style, that the projector lens, disposed in the case behind such ice, follow as much as possible the left curvature of the ice.

The lighting modules known to date do not allow to have an output lens that substantially follows a left curve while producing a satisfactory light beam, particularly with regard to the cut.

The object of the invention is, above all, to provide a lighting module for a motor vehicle headlamp, of the kind defined above, which comprises an exit lens in a left curve, having a curve both in plan view and in front view, and which gives a satisfactory cut-off beam.

Another object of the invention is to provide such a lighting module which makes it possible, by assembling several modules, to produce a code projector, in particular comprising a PBL function (abbreviation of the English term "Progressive Bending Light", for code turn progressive), that is to say a function providing progressive illumination in turns.

It is further desirable that the lighting module remains of a economical manufacture.

• la ligne moyenne de la lentille est formée par un arc de courbe gauche (constituant par exemple une approximation d'un segment d'une ligne moyenne gauche d'un galbe du véhicule),
• et un système optique correcteur est prévu entre le réflecteur et la lentille pour l'obtention d'une ligne de coupure satisfaisante en fonction de la géométrie de la face d'entrée et de la face de sortie de la lentille.

According to the invention, a projector module as defined above also has the following characteristics:

• the mean line of the lens is formed by a left curve arc (constituting, for example, an approximation of a segment of a mean left line of a curve of the vehicle),
• and a corrective optical system is provided between the reflector and the lens to obtain a satisfactory cut line according to the geometry of the input face and the exit face of the lens.

In the remainder of this text, the terms "vertical", "horizontal" refer to the positioning of the module once mounted in the projector, itself mounted in the vehicle. We can depart slightly verticality or horizontality described in the strict sense remaining in the spirit of the present invention.

The exit face of the lens is obtained by sliding along the left curve arc a forward convex arc in vertical planes.

The entrance face of the lens is obtained by a sliding, similar to that of the exit face, of a second curve arc calculated so that the lens is stigmatic between a point situated behind the apex of the lens on the lens. optical axis of the lens, this in a two-dimensional construction, identical in all the parallel vertical planes containing the curves, and the infinite

Preferably, the arc of left curve, constituting the approximation of a segment of the mean line, is seen from above in a circular arc and is seen from front to another arc. Each arc is an approximation of the top view and the front view of the segment of the average line of the curve of the vehicle, and admits the same tangents at the ends. The angular extent of an arc constituting the approximation of a segment is preferably at most equal to 90 °.

Advantageously, the convex arc forward that is slid to obtain the exit face of the lens is an arc of a circle located in a vertical plane. The vertical plane of the successive circular arcs may either remain parallel to itself and orthogonal to the transverse direction, or may revolve around a point.

For a flat-cut beam, the module comprises a folder with an arcuate front edge, the reflector is determined to give a wave surface along this line in a circular arc, and the correcting optical system is formed by a blade whose output face is constituted by a vertical axis cylinder, while the input face of the corrective optical blade is calculated to the optical path between the circular edge of the folder and a cylindrical outlet wave surface is constant.

For a V-cut beam, in particular with a horizontal leg and a rising leg inclined at 15 °, the module comprises a V-shaped straight edge bender in the vicinity of the optical axis, the output wave surfaces are formed by planes orthogonal to the optical axis, and the correcting optical system is formed by a corrective lens whose input face is calculated so that the optical path between the second focus of the elliptical reflector and the output wave surface is constant.

The bow convex forward that is slid to obtain the exit face of the lens is preferably an arc of a circle located in a vertical plane. And the vertical plane of successive circular arcs can remain parallel to itself and orthogonal to the transverse direction.

The vertical plane of successive circular arcs can also be perpendicular to the projection of the left curve arc on a horizontal plane (in top view).

According to one embodiment, in order to obtain a flat cut-off beam, the module comprises a folder with an arcuate front edge, the reflector is determined to give a wave surface along this arcuate line, and the system corrective optical system is formed by an optical plate whose output face is constituted by a cylinder of vertical axis, while the input face of the optical plate is calculated so that the optical path between the circular edge of the folder and a output cylindrical wave surface is constant.

According to another embodiment, to obtain a V-cut beam, the module comprises a folder with a straight V-edge in the vicinity of the optical axis, the output wave surfaces are formed by orthogonal planes at the optical axis, and the corrective optical system is formed by a corrective lens whose input face is calculated so that the optical path between the second focus of the elliptical reflector and the output wave surface is constant.

The invention also relates to a motor vehicle headlamp giving a cut-off beam, in particular a code projector or fog lamp, and which comprises at least two lighting modules as defined above and juxtaposed so that the surface projector output is smooth and continuous in a left shape.

A code projector is advantageously produced with at least one lighting module as defined above and making a V-cut, this module being disposed on the side of the longitudinal axis of the vehicle, and with at least one flat-cut module juxtaposed towards the outside the V-cut module.

The projector code may include several V-cut modules juxtaposed, on the side of the longitudinal axis of the vehicle, followed to the outside by several modules with horizontal cut. In particular, four inward V-cut modules and four out-of-plane modules can be provided, making a total of eight modules for the projector. The lighting control of the modules can be controlled by the steering angle of the vehicle, so that the outwardly facing horizontal modules are gradually switched on when the vehicle follows a turn within which the vehicle is located. the projector considered.

• Fig. 1 est une vue schématique de dessus du bord extérieur avant gauche d'un véhicule avec un projecteur lumineux selon l'invention.
• Fig. 2 est une vue schématique de face du bord avant gauche de Fig. 1 et du projecteur.
• Fig. 3 est une épure à plus grande échelle des projections sur un plan vertical et sur un plan horizontal de la ligne moyenne gauche du galbe de la glace du projecteur lumineux.
• Fig. 4 est un schéma en perspective illustrant la construction de la lentille de sortie du module.
• Fig. 5 est une vue schématique en plan illustrant la détermination du système optique correcteur dans le cas d'un module à coupure plate avec plieuse à bord circulaire.
• Fig. 6 est un schéma illustrant la détermination du système optique correcteur dans le cas d'un module à coupure en V avec plieuse dont le bord avant est situé dans un plan vertical orthogonal à l'axe optique du réflecteur.
• Fig.7 est une vue de face de la plieuse de Fig.6.
• Fig. 8 est une vue de face d'un projecteur situé du côté droit du véhicule et comportant deux modules à coupure plate selon l'invention, juxtaposés.
• Fig. 9 est une vue en perspective de dessus et de l'arrière des éléments optiques du projecteur de Fig. 8.
• Fig. 10 est une vue de dessus du projecteur de Fig. 9.
• Fig. 11 est un schéma du réseau de courbes isolux obtenu avec le projecteur de Fig. 9 et 10.
• Fig. 12 est une vue de face d'un projecteur selon l'invention obtenu par juxtaposition de deux modules d'éclairage à coupure en V.
• Fig. 13 est une vue en perspective de l'arrière et de dessus du projecteur selon Fig. 12.
• Fig. 14 est une vue de dessus du projecteur de Fig. 13.
• Fig. 15 est un schéma du réseau de courbes isolux obtenu avec le projecteur de Fig. 12 à 14.
• Fig. 16 est une vue en perspective de dessus et de l'arrière d'un projecteur code, côté droit d'un véhicule, composé de huit modules selon l'invention juxtaposés, et
• Fig. 17 montre, semblablement à Fig. 16, le projecteur code situé du côté gauche du véhicule.

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 schematic view from above of the left front outer edge of a vehicle with a light projector according to the invention.
• Fig. 2 is a schematic front view of the left front edge of Fig. 1 and the projector.
• Fig. 3 is an enlarged sketch of projections on a vertical plane and on a horizontal plane of the left middle line of the ice curve of the luminous headlamp.
• Fig. 4 is a perspective diagram illustrating the construction of the output lens of the module.
• Fig. 5 is a schematic plan view illustrating the determination of the corrective optical system in the case of a flat cut module with a circular edge folder.
• Fig. 6 is a diagram illustrating the determination of the corrective optical system in the case of a V-cut module with a folder whose front edge is located in a vertical plane orthogonal to the optical axis of the reflector.
• Fig.7 is a front view of the folder of Fig.6 .
• Fig. 8 is a front view of a projector located on the right side of the vehicle and comprising two flat cut modules according to the invention, juxtaposed.
• Fig. 9 is a perspective view from above and from the rear of the optical elements of the projector of Fig. 8 .
• Fig. 10 is a top view of the projector from Fig. 9 .
• Fig. 11 is a diagram of the network of isolux curves obtained with the projector of Fig. 9 and 10 .
• Fig. 12 is a front view of a projector according to the invention obtained by juxtaposition of two V-cut lighting modules.
• Fig. 13 is a perspective view of the back and top of the projector according to Fig. 12 .
• Fig. 14 is a top view of the projector from Fig. 13 .
• Fig. 15 is a diagram of the network of isolux curves obtained with the projector of Fig. 12 to 14 .
• Fig. 16 is a perspective view from above and from the rear of a code projector, right side of a vehicle, composed of eight modules according to the invention juxtaposed, and
• Fig. 17 shows, similarly to Fig. 16 , the projector code located on the left side of the vehicle.

Referring to Fig. 1 and 2 it is possible to see the left front end of a vehicle A equipped with a luminous projector B according to the invention, the exit lens LTL of which follows a left curve substantially parallel to the left middle line G (ie say in three dimensions) of the mirror 1 of the projector, to be consistent with the style of the car manufacturer.

The left curve G in top view ( Fig. 1 ) has an arcuate shape Gh. This same curve G seen from the front ( Fig. 2 ) also has an arcuate form Gv, usually different from the Gh form.

On the Fig. 1 and 2 in each projection plane, a system of orthogonal axes has been represented. In the horizontal plane, the axis Ox is parallel to the longitudinal direction of the vehicle while the axis Oy corresponds to the transverse direction. The Oz axis corresponds to the vertical direction.

The size of the B projector housing in the Ox direction ( Fig. 1 ) is limited due to the imperatives of automobile construction. As a result, the light source is relatively close to the ice 1 which may be subjected to too much heating. This would be the case in particular with a mirror made of a transparent plastic material and if the light source was of the halogen lamp type. To avoid such difficulties, the light source is constituted by at least one light emitting diode.

Projector B is composed of several juxtaposed M, Ma modules, as explained more fully about Fig.16 and 17 ,

Fig. 5 schematically illustrates a projector module M according to the invention, giving a flat-cut beam. This module M comprises a concave reflector R of the type described in the aforementioned patent FR 2,872,257 , and a light source S formed by at least one light-emitting diode for illuminating at least upwards, this diode being located in the vicinity of the first internal focus of the reflector R. The module M further comprises a folder 2, that is to say a substantially horizontal plate, the upper surface of which is reflective and whose front edge 3 passes through, or in the vicinity of, the second focus of the reflector R to create the cut line. according to Fig. 5 the front edge 3 of the folder is constituted by a circular arc convex to the front.

The terms "front" and "rear" are to be understood according to the direction of propagation of the light reflected by the reflector R.

The reflector R is determined to transform the spherical wave surface from the source S into a wave surface coincident with the leading edge 3, so that the cutoff line of the beam is flat horizontal.

Fig. 6 schematically illustrates a projector module Ma according to the invention, with a reflector Ra ellipsoid type or, for simplification, called elliptical type, giving a V-cut beam. The front edge 3a of the folder 2a is located in a plane vertical orthogonal to the axis of the reflector Ra, the edge 3a passing through the second focus of the reflector. The edge 3a of the folder has a V shape in the vicinity of the optical axis, ( Fig.7 ) corresponding to the desired cutoff for the beam.

A lens L ( Fig. 5 ), The ( Fig. 6 ) is located in front of the reflector and the light source.

As stated about Fig. 1 and 2 it is desired that the LTL projector output assembly lens for the left side, or LTR for the right side, has a continuous curved outer surface along the left middle line of the projector B glass outline. moreover, that in a projector consisting of several juxtaposed modules, the successive output lenses L, La juxtaposed modules are connected in a continuous line to give a set lens LT L, or LTR having a smooth exit surface.

The entrance surface of the assembly lens LTL, LTR and the input surface of the lenses L, The juxtaposed modules must be smooth to avoid parasites such as shiny lines, or other, between the successive lenses of the juxtaposed modules. In addition, it must be possible to produce a code beam with a V cut having a horizontal leg and an inclined branch rising to 15 °.

Fig. 3 illustrates, on a larger scale than on Fig. 1 and 2 , the front view Gv and the top view Gh of the average line of a projector B to be produced with a set of modules according to the invention.

For the construction of the modules composing the projector, the line G is fictitiously cut into successive segments G1, G2,... Projecting on a transverse vertical plane into segments Gv1, Gv2 ... and on a horizontal plane into segments Gh1, Gh2 .... Each segment G1, G2 ... corresponds to a module M1, M2 ... and to a diode of the associated module.

For each projection segment thus determined, we consider the ends, for example Ev1 and Ev2 for the segment Gv1, as well as the tangents Tv1, Tv2 at these ends. The tangents form with the horizontal direction parallel to the direction Oy angles α1, α2.

For the construction of the output lens of the module M1 corresponding to the arc G1, an approximation of the segment Gv1 is established by an arc having an end E'v1, end of the preceding segment, known from the approximation of Gv, and an end E'v2 situated at a distance y of E'v1 equal to the following distance between Ev1 and Ev2, and admitting the same tangents Tv1, Tv2 at these two ends. The center of this arc is a point ω1; the angular extent of the arc is preferably less than or equal to 90 °. The next segment Gv2 is approximated in the same way by an arc starting from point E'v2 and ending at an end of the same side along y that Gv2 with the same tangents at both ends, and so on for the whole curve Gv which is replaced by a succession of arcs of circle very close to the real curve (if the first end E'vx coincides with Ev1, the ends E'vn deviate more and more from Evn in general when n ).

We proceed in the same way for the horizontal projection Gh. The pitch J in the direction Oy of the successive segments may be regular or may vary to take account of the change of curvature of the line.

We denote by r ( Fig.4 ) the left curved mean line which is seen from above and from above according to the two arcs constituting the approximations of Gv1 and Gh1. The curve r is the guideline of the exit face 4 of the lens.

To make the smooth exit face 4 ( Fig. 4 ) of the lens L is slid along the mean line r, a curve arc 5 convex forwardly in a vertical plane. The curvature of the arc 5 makes it possible to avoid reflections. Preferably the curve arc 5 is an arc of a circle which delimits an angular sector of which a point, for example the middle of the string subtending the arc 5, moves along the curve r.

According to a first possibility, the plane of the arc 5 remains parallel to itself during the displacement, and orthogonal to the transverse direction Oy. According to another possibility, the plane of the arc of a circle is substantially perpendicular to the projection of the curve r in the plane (O, x, y) and thus revolves around a vertical axis passing through the center of the circle serving as an approximation to the segment Gh.

The smooth input face 6 ( Fig.5 ) of the lens L, that is to say the face turned towards the source S, is obtained by sliding a curve arc 7 ( Fig.4 ) of appropriate shape on the average line r in a manner similar to the curve arc 5 of the input face.

The equation of the curve r can be determined from the known points of the curve G and the choice of the arcs of circle Gv1 ... Gh1. This equation makes it possible to calculate a lens L, La for the following module, contiguous to the previous one and in continuity of tangency with it.

Calculation of the exit area 4.

We consider a vertical output profile 5 in a circular arc, of radius r, which leads to a toric output face if α1 = α2 and cylindrical if, in addition, β1 = β2 ( Fig.3 ). β1 and β2 are the angles formed with the transverse direction Oy by the tangents at the ends of the horizontal projection Gh1 of the curve segment considered.

The equation of the smooth exit surface 4 can then be established from the equation of the curve r, the radius r of the arc 5 and the relative position of this arc with respect to the curve r.

In order to determine the smooth input face of the lens, in a vertical plane perpendicular to the direction Oy, a curve arc profile 7 corresponding to a stigmatic lens is sought between a point T0, situated behind the top of the lens. as illustrated by the diagram of Fig. 4 , and infinity (construction in one of the vertical planes containing the exit arc as explained above).

An optical correction system D ( Fig. 5 ) or Da ( Fig. 6 ) is provided between the reflector R, Ra and the lens L, La for obtaining a satisfactory cut line in the light beam.

Corrective optical system for a flat cut.

We consider a module according to Fig. 5 whose reflector assembly R and the folder 2 generate a toric wave coming from the circular edge 3 of the folder 2. The reflector R is determined to transform a spherical wave surface from the source S into a waving wave surface. at the arc of circle 3 located in the plane of the horizontal plate 2 forming the folder.

A correction optical system D is calculated between the output lens L defined above and the edge 3 of the folder so that the ring wave coming from the edge 3 of the folder is transformed into a vertical axis cylindrical wave surface. whose traces on the horizontal plane are concentric circles 8 ( Fig. 5 ), of vertical axis Δ. The position of this axis Δ is variable: it is a parameter making it possible to adjust the horizontal spreading of the light beam, and possibly to create a horizontal shift of its mean direction.

For the calculation, we consider any point P of the exit surface of the lens L. A light ray from this point and belonging to the cylindrical wave desired output is carried by a straight line passing through P, intersecting the vertical axis Δ of the cylindrical wave and perpendicular to this axis. The equation of the straight line of the light beam 9 can then be determined taking into account the coordinates of the point P.

The optical path traveled in the air between the cylindrical wave surface 8 and the point P located on the exit face can then be determined.

The ray 9 is then extended in the opposite direction to that of the propagation of light.

Since the equation of the exit surface 4 of the lens L has been established previously, the normal can be calculated at this P-shaped surface. Knowing the refractive index n of the lens L, the direction of the refracted ray 10 can be determined. in the thickness of the lens L, corresponding to the radius 9. The intersection point N of the radius 10 is determined with the input face 6 of the lens L. The normal is then determined at the input face 6 at the point N and the refracted ray 11 in inverse propagation in the air which separates the lens L from the correction system D.

It is assumed that the output face 12 of the intermediate corrective optical system D is cylindrical, of vertical axis meeting the axis of symmetry of the reflector (which is not necessarily the longitudinal axis Ox of the vehicle). This surface 12 is a "free" diopter whose choice is arbitrary, said surface can then be modified to optimize the sharpness of the cuts, using an optimization software (which does not change the rest of the construction but simply change the equation giving P 'and the normal to P').

The intersection P 'of the radius 11 is then calculated with the cylindrical surface 12 as well as the normal at the surface 12 at the point P'. The refracted ray 13 is deduced therefrom inside the optical system D.

We then seek the point N 'intersection of the radius 13 and the input face 14 of the correction system D. For this, we write the optical equation translating the constancy of the optical path between the cylindrical wave surface from which the radius 9 and the edge 3 of the folder.

By evaluating the optical path for a central point of the exit face 4 of the exit lens L, the constant can be calculated by setting the thickness near the center of the corrective optical plate, and thus the coordinates of the point N 'and determine the unknown surface 14 constituting the input face of the optical correction system D by varying the point P.

Corrective optical system for V cut

In this case, the reflector is determined so that the output wave is a plane wave whose traces on a horizontal plane passing through the optical axis are straight 15 ( Fig. 6 ) parallel to each other and perpendicular to the longitudinal axis of the vehicle.

The front edge 3a of the folder is located in a plane orthogonal to the axis of the reflector Ra. This edge 3a seen from the front has a V shape ( Fig. 7 ) inverted with respect to the desired cutoff line in the vicinity of the optical axis. The edge 3a is formed of a horizontal branch 3ah and a branch 3ai inclined at 15 ° on the horizontal. The central point 16 of the edge of the folder, corresponding to the tip of the inverted V, is located on the geometric axis of the reflector Ra which can form an angle with the longitudinal axis of the vehicle.

The plane exit wave having traces for the straight lines 15 corresponds to the transformation by the corrective optical system Da and the exit lens La of a spherical wave coming from the central point 16 of the edge of the folder. The optical correction system Da consists of a corrective lens. The exit lens La and the corrective lens Da are equivalent to a stigmatic lens between a point and infinity, in particular equivalent to a lens such as those used in elliptical lighting modules. But the exit face of the lens La is very different from the output face of a conventional elliptical module, and causes a different style. The free diopter corresponding to the output face 12a of Da allows an optimization of the cutoff sharpness when moving away from the focus. The determination of the output faces 12 or 12a to optimize the sharpness of the cuts can be performed using software.

To determine the input face 14a of the correction lens Da ( Fig.6 ) the procedure is analogous to that described for Fig. 5 . The same numerical or literal references were taken back followed by the letter "a" and the description will not be repeated in detail. We always consider a ray 9a by propagating it in the opposite direction of light. The radius 9a is perpendicular to the plane plane wave surfaces 15, that is to say that the radius 9a is parallel to the longitudinal axis of the vehicle. The distance from the point N'a to the point 16 located at the second focus of the elliptical reflector Ra can be calculated according to the parameters. By writing the constancy of the optical path between the point 16 and a trace wave surface 15, the coordinates of the point N'a and the equation of the surface 14a can be determined.

Referring to Fig. 8 , we can see, from the front, a projector for the right side of a vehicle, composed of two modules M1, M2 juxtaposed, flat cut according to Fig. 5 . The output faces 4.1 and 4.2 connect continuously to form a set lens LTR1 with smooth output face. The lower edge 17 and the upper edge 18 of the exit face are not in a horizontal plane, but have an arcuate shape in front view, the left end of an edge being higher than the right end.

Fig. 9 is a perspective view of the rear of the two modules M1, M2 juxtaposed to give the exit face of Fig. 8 . The exit lenses L1, L2 are in the extension of one another, the entry face of these lenses 6.1, 6.2 admitting a section by a convex arc-shaped longitudinal vertical plane turning its convexity towards the back while the sections of these faces by horizontal planes correspond to curve arcs turning their concavity backwards.

The intermediate correcting systems D1, D2 have a cylindrical vertical outlet face 12.1, 12.2. The input faces 14.1, 14.2 have a relatively complex shape corresponding substantially to that obtained by twisting a rectangular band. Twisting appears on Fig. 10 , in top view.

The reflectors R1, R2, seen from above, have two half-shells connecting in a median longitudinal vertical plane following a hollow zone, forming a kind of valley. The folder 2.1, 2.2 has a front edge 3.1, 3.2 in a circular arc of large radius.

Front view ( Fig.8 ) and top view ( Fig.10 ), the output face of the overall lens LTR1 of the projector has a curved arc-shaped middle line.

Fig. 11 shows the network of isolux curves obtained with a projector such as that of Fig. 8 to FIG. 10 . The light beam has a horizontal cutoff line.

Fig. 12 shows in front view a projector of a vehicle, consisting of two modules Ma1, Ma2 giving a V-cut beam at 15 ° for traffic on the right. The output face of the overall lens lens LTR2, constituted by the juxtaposition of the lenses La1, La2, has a lower longitudinal edge 17a and an upper longitudinal edge 18a with a double S curvature, the left end of the transverse edges being situated at a level higher than that of the right end. Each longitudinal edge has a point of inflection between its ends. Sure Fig. 12 the edges 3a1, 3a2 of the folders are shown front views.

Fig. 13 shows in perspective, from the back and from above, the two modules Ma1, Ma2 juxtaposed the projector of Fig. 12 . The entry faces 6a1, 6a2 of the exit lenses La1, La2 admit, in section along a longitudinal vertical plane, a line of curved section convex towards the rear while the section of these faces by a horizontal plane gives a line of concave curved section towards the rear, visible on Fig. 13 .

The input faces 14a1, 14a2 of the corrective lenses Da1, Da2 admit, in horizontal section, a curve arc convex backwards turning its vertex to the corresponding reflector. The section of these faces 14a1, 14a2 Longitudinal vertical planes are constituted by weakly arched segments, close to rectilinear segments. The sections in the longitudinal vertical plane passing through the geometric axis of the reflectors correspond to curve arcs convex towards the reflector. The convexity of the vertical sections of the faces 14a1, 14a2 towards the reflector gradually decreases when one deviates from the median vertical plane, this convexity being able to cancel out and to become a concavity. The exit face 12a1, 12a2 of the corrective lenses is a cylindrical surface with vertical generatrices.

The reflectors Ra1, Ra2 comprise an ellipsoid-shaped main portion and, forwardly, on each side of the median vertical plane, two curved, concave downwardly, substantially triangularly contoured surfaces 19.1, 20.1 and 19.2, 20.2 ending on each side the elliptical reflector to increase the luminous flux in the beam (essentially elliptical surfaces with foci close to those of the main section of the reflector would not send the light into the "correct" corrective lens and the corresponding rays would be lost or sources of parasitic rays, such as spots in the beam in particular, in large width). The front edge of the surfaces 19.1 and 20.1 on the one hand and 19.2, 20.2 is located in the vertical plane passing through the edge of the folder. The light-emitting diodes constituting the light sources S are schematically represented at the internal focus of the reflector.

Fig. 15 is the diagram of isolux curves obtained with a projector according to Fig. 12 to FIG. 14 , with V cut.

Fig. 16 is a perspective view from above and from the rear of a code projector, for the right side of a vehicle, consisting of eight modules according to the invention, juxtaposed so that the exit face of the overall lens LTR is smooth and continuous. The lens LTR follows a left line that rises from the end on the side of the longitudinal axis of the vehicle towards the other end outwardly. In top view and in front view, the LTR lens is arcuate convex outward.

• vers l'intérieur, quatre modules Ma1, Ma2, Ma3, Ma4 du type décrit à propos de Fig. 6 et Fig. 12 à 14, donnant un faisceau à coupure en V,
• et vers l'extérieur, quatre modules M1-M4 du type décrit à propos des Fig. 5 et Fig. 8 à 11 donnant un faisceau à coupure horizontale pour éclairer sur le côté du véhicule.

The projector includes:

• inward, four modules Ma1, Ma2, Ma3, Ma4 of the type described about Fig. 6 and Fig. 12 to 14 , giving a V-cut beam,
• and outward, four M1-M4 modules of the type described with respect to Fig. 5 and Fig. 8 to 11 giving a horizontal cut beam to illuminate on the side of the vehicle.

The projector complies with Fig. 16 may be of the PBL type, that is to say, progressive-illumination cornering projector, for example by controlling the successive ignition of the external modules M1-M4 according to the steering of the vehicle towards inside a right turn.

Fig. 17 is a view similar to that of Fig. 16 of the searchlight code located on the left side of the vehicle with LTL assembly lens. The four V-cut modules are inward and the four horizontal cut-off modules are facing outward.

The invention makes it possible to produce a module with an exit lens with a left curvature, giving a cut-off beam, in particular a V-beam, while ensuring an improved style. The exit lens can follow three-dimensional curves and is no longer limited to a two-dimensional curve. The entire projector comprises a free diopter allowing optimization with the conventional means of optical calculation to improve the sharpness of the V-shaped cuts. One can notably mention the one (inclined plane) represented for Ma1 in figure 17 . Using such a dioptre here makes it possible to reduce the thickness and to improve the effectiveness of the corrective lens while optimizing the sharpness of the cut with respect to a cylindrical type of diopter. The principle of optical construction remains the same and is even simplified (a straight / flat intersection rather than a straight intersection / cylinder).

Claims (14)

1. Motor vehicle headlight module for a cutoff beam, comprising a concave reflector (R, Ra), a light source (S) disposed in the concavity of the reflector, and a lens (L, La) situated in front of the reflector and the light source, which is formed by at least one light emitting diode for illuminating at least upwards, the reflector being associated with a bender (2, 2a) of which the top face is reflective in order to bend the beam coming from the reflector, the said bender comprising a front end edge (3, 3a) capable of forming the cutoff in the lighting beam, module in which the exit surface (4, 4a) of the lens is chosen so as to be able to be connected in a continuous surface with the exit surfaces of the lenses of adjacent modules, characterised in that:

   - the midline (Γ) of the lens is formed by a skew curve of arc, and the smooth exit face (4) of the lens (L) is obtained by sliding along the midline a forwardly convex curve of arc (5) situated in a vertical plane, and the smooth entry face (6) of the lens (L), that is the face turned towards the source (S), is obtained by sliding a curve of arc (7) of appropriate shape along the midline in a manner similar to the curve of arc (5) of the exit face,

   - and a correcting optical system (D, Da) is provided between the reflector and the lens for obtaining a satisfactory cutoff line, according in particular to the geometry of the entry face and the exit face of the lens.
2. Module according to claim 1, characterised in that the exit face (4, 4a) of the lens is obtained by sliding along the skew curve of arc (Γ) a forwardly convex arc (5) situated in vertical planes.
3. Module according to claim 2, characterised in that the entry face (6, 6a) of the lens is obtained by a sliding, similar to that of the exit face, of a second curve of arc (7) calculated so that the lens is stigmatic in each of the said vertical planes between a point situated rearward of the top of the lens on the optical axis, and infinity.
4. Module according to any one of the preceding claims, characterised in that the skew curve of arc (Γ), constituting the approximation of a segment of the midline (G), is seen from above on an arc of circle and is seen in front view on another arc of circle, each arc of circle being an approximation of the plan view (Gh1, Gh2, etc.) and of the front view (Gv1, Gv2, etc.) of the associated segment (G1, G2, etc.) of the midline (G), and admitting the same tangents at the ends.
5. Module according to claim 1, characterised in that the angular extent of an arc of circle constituting the approximation of a segment (G1, G2, etc.) is at most equal to 90°.
6. Module according to any one of the preceding claims, characterised in that the forwardly convex arc (5) that is made to slide in order to obtain the exit face of the lens is an arc of circle situated in a vertical plane.
7. Module according to claim 4, characterised in that the vertical plane of the successive arcs of circle (5) remains parallel to itself and orthogonal to the transverse direction.
8. Module according to claim 6, characterised in that the vertical plane of the successive arcs of circle (5) is perpendicular to the projection of the skew curve of arc (Γ) on a horizontal plane.
9. Module according to any one of the preceding claims, characterised in that, for a beam with a flat cutoff, the module (M) comprises a bender (2) with a front edge (3) in an arc of circle, the reflector (R) is determined so as to give a wave surface along this line in an arc of circle, and the correcting optical system (D) is formed by an optical blade of which the exit face (12) is formed by a cylinder of vertical axis (Δ), while the entry face (14) of the optical blade is calculated so that the optical path between the circular edge (3) of the bender and a cylindrical exit wave surface (8) is constant.
10. Module according to any one of claims 1 to 8, characterised in that, for a beam with a V-shaped cutoff, the module (Ma) comprises a bender (3a) with a V-shaped rectilinear edge close to the optical axis, the exit wave surfaces (15) are formed by planes orthogonal to the optical axis, and the correcting optical system (Da) is formed by a correcting lens of which the entry face (14a) is calculated so that the optical path between the second focus of the elliptical reflector (Ra) and the exit wave surface (15) is constant.
11. Motor vehicle headlight giving a cutoff beam, in particular a dipped headlight or a fog light, characterised in that it comprises at least two lighting modules (M, Ma) according to any one of the preceding claims, juxtaposed so that the exit surface of the headlight is smooth and continuous in a skew shape.
12. Dipped headlight according to the preceding claim, characterised in that it comprises at least one lighting module (Ma) producing a V-shaped cutoff, this module being disposed on the side of the longitudinal axis of the vehicle, and at least one module with flat cutoff (M) juxtaposed towards the outside with the module with V-shaped cutoff.
13. Dipped headlight according to the preceding claim, characterised in that it comprises several juxtaposed modules with V-shaped cutoff (Ma1, Ma2, etc.), on the side of the longitudinal axis of the vehicle, followed towards the outside by several modules with horizontal cutoff (M1, M2, etc.).
14. Dipped headlight according to the preceding claim, characterised in that the control of the lighting of the modules is slaved to the steering angle of the vehicle, so that the modules with horizontal cutoff situated towards the outside are progressively illuminated when the vehicle follows a bend on the inside of which the headlight in question is situated.

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