EP0628765A1 - Vehicle headlamp with ellipsoidal type light reflector - Google Patents

Vehicle headlamp with ellipsoidal type light reflector Download PDF

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Publication number
EP0628765A1
EP0628765A1 EP94400828A EP94400828A EP0628765A1 EP 0628765 A1 EP0628765 A1 EP 0628765A1 EP 94400828 A EP94400828 A EP 94400828A EP 94400828 A EP94400828 A EP 94400828A EP 0628765 A1 EP0628765 A1 EP 0628765A1
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EP
European Patent Office
Prior art keywords
mirror
horizontal
lens
convergence
focal plane
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Granted
Application number
EP94400828A
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German (de)
French (fr)
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EP0628765B1 (en
Inventor
Laurent Mottet
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Valeo Vision SAS
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Valeo Vision SAS
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/30—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by reflectors
    • F21S41/32—Optical layout thereof
    • F21S41/33—Multi-surface reflectors, e.g. reflectors with facets or reflectors with portions of different curvature
    • F21S41/337—Multi-surface reflectors, e.g. reflectors with facets or reflectors with portions of different curvature the reflector having a structured surface, e.g. with facets or corrugations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/30—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by reflectors
    • F21S41/32—Optical layout thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/30—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by reflectors
    • F21S41/32—Optical layout thereof
    • F21S41/33—Multi-surface reflectors, e.g. reflectors with facets or reflectors with portions of different curvature
    • F21S41/334—Multi-surface reflectors, e.g. reflectors with facets or reflectors with portions of different curvature the reflector consisting of patch like sectors

Definitions

  • the present invention relates generally to headlamps of the elliptical type for motor vehicles.
  • elliptical projector is meant a projector comprising a light source, a mirror capable of concentrating the light coming from the source towards a region of concentration situated in front of the source, a lens placed in front of the mirror so that its focal plane is neighbor of the concentration region, and a closing window.
  • a mask is also provided in the focal plane of the lens, one edge of which defines said cut.
  • the mirror is purely ellipsoidal, with the source disposed on its first focal point, in which case there is a concentration of the radiation in an essentially circular pattern around the second focal point, through which the focal plane of the lens passes.
  • document FR-A-2,516,203 describes a projector of the type indicated above, in which areas are provided on the mirror which are not reflective, specifically positioned so as to reduce the proportion of vertical images of the filament in the beam formed. There is thus obtained at the focal plane of the lens a flatter light spot, facilitating the correction work to be carried out by the glass. However, the light output of the projector is further reduced, and the width of the beam before the lens remains limited.
  • Document FR-A-2 554 546 also discloses a projector of the same type, in which the mirror is a kind of flattened ellipsoid, resting vertically on an ellipse with an interior focus on the source and with a focus exterior is in the vicinity of the focal plane of the lens, and resting horizontally on a different ellipse, the interior focus of which is also on the source but the exterior focus of which is located in front of the abovementioned focal plane.
  • document EP-A-0 153 485 discloses a projector in which an attempt has also been made to produce a large light spot at the second focal point of a mirror of the elliptical type. But here again, the mirror is designed discreetly, strip by strip, with consequently the same drawbacks.
  • the invention aims to overcome these drawbacks of the prior art, and to provide a motor vehicle headlight of the elliptical type in which a wide beam can be obtained with a mirror of generally smooth shape and without breaking the slope. To this end, it proposes a projector as defined in claim 1.
  • a projector which comprises a light source 10 of small dimensions, such as the filament of an incandescent lamp or the arc of a discharge lamp, a mirror 20 for recovering and concentrating the light flux emitted by the source, a mask 30 placed in a well-determined position in front of the mirror 20 and intended to form, by occultation of part of the incident radiation, a luminous image of shape and determined light distribution suitable for a passing beam, a converging lens 40, for example a plano-convex lens, the focal plane of which is situated at the level of the mask 30, and finally a closing glass 50 preferably smooth or slightly deflecting.
  • a light source 10 of small dimensions such as the filament of an incandescent lamp or the arc of a discharge lamp
  • a mirror 20 for recovering and concentrating the light flux emitted by the source
  • a mask 30 placed in a well-determined position in front of the mirror 20 and intended to form, by occultation of part of the incident radiation, a luminous image of shape and determined
  • the mirror 20 is of the ellipsoidal genus with two focal points situated on its axis
  • the source 10 is placed in the vicinity of the first focal point while the mask 30 is placed in the vicinity of the second focal point, where the reflected light converges by the mirror.
  • the mirror comprises at least one zone such that the point of convergence of the radiation, in projection in a horizontal plane, that is to say the point which corresponds to the second focus of an ellipsoid, varies as that we move laterally from the optical axis of the mirror.
  • FIG. 1 shows that the mirror 20 has a central zone or bottom zone 21 which is optically characterized by a first focal point FR, on which the source 10 is placed, and by a second focal point FS, fixed, towards which the whole of the radiation reflected by this zone 21 converges.
  • This focal point FS is located in the plane of the mask 30 and preferably in the vicinity of an edge 31 of said mask itself intended to define a cut-off of the generated beam.
  • this zone 21 has a similar behavior, with the same foci FR and FS.
  • This zone 21 can therefore be constituted by a portion of ellipsoid of revolution of FR and FS homes.
  • This zone 21 is to create a relatively concentrated central spot at the focal plane of the lens 40.
  • the mirror 20 also comprises two lateral zones 22a and 22b produced according to the present invention.
  • the zone 22a extends laterally up to a limit denoted y max . At this level, the current horizontal focus Fc reaches an extreme forward position on the axis Ox, denoted FT.
  • the relation between the dimension yc, varying between y min and y max , and the current horizontal focus Fc can be any monotonic relation, for example a linear relation. Non-linear relationships are of course conceivable.
  • the zone 22a behaves differently, that is to say that, whatever the dimension in y of a vertical section of the mirror, the convergence in the vertical plane preferably occurs on the line D parallel to y'y and passing through the focal point FS or in the vicinity of this line. This behavior is illustrated in Figure 2.
  • the opposite lateral zone 22b behaves symmetrically in this case from the zone 22a with respect to the optical axis 0x, and this behavior will not be repeated here.
  • the lateral zones 22a and 22b of the mirror cooperate to generate in the focal plane of the lens 40 a light spot which is vertically little thick, insofar as the vertical convergence always takes place in the vicinity of the line D mentioned above.
  • this thickness depends only on the dimensions of the source 10.
  • the mirror 20 according to the invention therefore makes it possible to generate at the level of the mask 30 a light spot of which a part is a concentrated central spot, intended to give the projected beam its range, and of which another part is a wide and not very thick spot. , intended to give the beam its width. It is also observed that, insofar as the zones 22a, 22b do not appreciably increase the vertical height of the spot relative to the case of an ellipsoid of revolution, the light output is not degraded because it does not appreciably increase not the proportion of light obscured by the mask 30.
  • FIG. 3a a spot of general circular outline is observed, which follows from the shape of revolution of the mirror.
  • the spot has a marked central concentration and at the same time a large width, without being higher vertically than that of FIG. 3a.
  • FIG. 4 illustrates by a set of isolux curves Ci on a standardized projection screen the appearance of the beam obtained, without the intervention of the closing glass.
  • the beam is thin, which allows not to light the road too close to the vehicle.
  • FIGS. 5 and 5a an alternative embodiment of a projector according to the present invention has been shown, the mirror of which has a central zone 21 in the form of an ellipsoid of revolution and two lateral zones 22a and 22b produced as described above and, between said central zone and the lateral zones, intermediate zones forming striations, respectively 23a and 23b.
  • These intermediate zones are produced by local deformation with respect to the mirror of FIG. 1, so as to disperse significantly the points of horizontal convergence on Ox obtained for vertical section of the intermediate zones.
  • the vertical convergence of the mirror is the same as in the case of FIGS. 1 and 2, that is to say that the light converges vertically preferably in the vicinity of the focal plane of the lens for all the points of the mirror.
  • the intermediate zones 23a and 23b are preferably connected continuously, and if necessary differentiable, with the neighboring zones 21 and 22a, 22b respectively.
  • the streaks are configured so as to respect the maximum levels of illumination authorized by the regulations, in particular in the region to the left of the concentration spot below the horizontal half-cut hH.
  • FIG. 6 illustrates, by isocandela curves C'i on a standardized projection screen, the shape of the beam obtained with a projector equipped with the mirror of FIG. 5, without the intervention of the glass. It is observed that the thickness of the beam in the axis (below the point H) is appreciably reduced compared to the case of FIG. 4, because a certain proportion of large vertical images or slightly inclined with respect to the vertical were scattered laterally.
  • a mask 30 is generally not provided, so that with the headlamp in FIGS. 1 and 2, the configuration photometric obtained will correspond to the curves of figure 3b without occultation.
  • a mask In the case of a fog light, a mask is provided with a rectilinear horizontal edge.
  • zones 22a and 22b are provided which shift the point of horizontal convergence forwards relative to the focal plane of the lens 40 as one moves away laterally of the axis 0x, it can of course be provided for these points of convergence to approach the focal plane PF when one moves away from the optical axis. This approach is moreover preferred in the case of an anti-fog beam.
  • the above variant can be easily implemented by using for the function h (

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

In the headlamp, light reflected from an incandescent or arc source (10) at the nearer focus (FR) of the uniformly elliptical central reflector (21) converges at the outer focus (FS), located at the focal plane (PF) of the lens (40). The lamp front is closed by a plain glass (50). While the outer reflecting zones (22a,22b) also reflect convergently in vertical planes, horizontally reflected rays cross the optical axis (Ox) progressively further forward (h(yc)) as the reflection point lies further out (yc). The beam appears at the focal plane as a bright central spot with lateral extensions of approximately uniform height. To produce cut-off, a vertical mask (30), with a top edge not extending higher than the optical axis (Ox), is fixed at the focal plane (PF).

Description

La présente invention concerne d'une façon générale les projecteurs du genre elliptique pour véhicules automobiles.The present invention relates generally to headlamps of the elliptical type for motor vehicles.

On entend par projecteur elliptique un projecteur comportant une source lumineuse, un miroir capable de concentrer la lumière issue de la source vers une région de concentration située en avant de la source, une lentille placée en avant du miroir de telle sorte que son plan focal soit voisin de la région de concentration, et une glace de fermeture.By elliptical projector is meant a projector comprising a light source, a mirror capable of concentrating the light coming from the source towards a region of concentration situated in front of the source, a lens placed in front of the mirror so that its focal plane is neighbor of the concentration region, and a closing window.

Dans le cas où le faisceau à former doit présenter une coupure, on prévoit également dans le plan focal de la lentille un masque dont un bord définit ladite coupure.In the case where the beam to be formed must have a cut, a mask is also provided in the focal plane of the lens, one edge of which defines said cut.

Classiquement, le miroir est purement ellipsoïdal, avec la source disposée sur son premier foyer, auquel cas on assiste à une concentration du rayonnement selon un motif essentiellement circulaire autour du second foyer, par lequel passe le plan focal de la lentille.Conventionally, the mirror is purely ellipsoidal, with the source disposed on its first focal point, in which case there is a concentration of the radiation in an essentially circular pattern around the second focal point, through which the focal plane of the lens passes.

Cette solution de base est cependant désavantageuse à plusieurs égards. Tout d'abord, lorsqu'un masque est prévu une partie très importante de la lumière concentrée est occultée par ce dernier, avec en conséquence un rendement lumineux pauvre.This basic solution is however disadvantageous in several respects. First of all, when a mask is provided, a very large part of the concentrated light is obscured by the latter, with consequently a poor light output.

Ensuite, étant donné que le rayonnement concentré au plan focal de la lentille présente une largeur limitée, il est nécessaire de prévoir des aménagements destinés à assurer un étalement du faisceau pour qu'il présente la largeur requise, imposée notamment par les règlements.Then, since the radiation concentrated at the focal plane of the lens has a limited width, it is necessary to provide arrangements intended to ensure spreading of the beam so that it has the required width, imposed in particular by regulations.

Des aménagements d'étalement prévus sur la glace ne sont généralement pas souhaitables dans le cas d'un projecteur elliptique, qui projette une image bien définie, car ils détériorent considérablement cette image. En outre, ces aménagements augmentent le coût de revient du projecteur et sont à l'origine de défauts optiques encore plus importants lorsque la glace présente une inclinaison importante.Spreading arrangements provided on the ice are generally not desirable in the case of an elliptical projector, which projects a well-defined image, since they considerably deteriorate this image. In addition, these arrangements increase the cost price of the projector and are the source of optical defects still more important when the ice has a large slope.

On connaît déjà un certain nombre de solutions à ce problème.A number of solutions to this problem are already known.

En particulier, le document FR-A-2 516 203 décrit un projecteur du type indiqué ci-dessus, dans lequel on prévoit sur le miroir des zones qui ne sont pas réfléchissantes, spécifiquement positionnées de manière à diminuer la proportion d'images verticales du filament dans le faisceau formé. On obtient ainsi au niveau du plan focal de la lentille une tache lumineuse plus plate, facilitant le travail de correction devant être effectué par la glace. Cependant, le rendement lumineux du projecteur est encore diminué, et la largeur du faisceau avant la glace reste limitée.In particular, document FR-A-2,516,203 describes a projector of the type indicated above, in which areas are provided on the mirror which are not reflective, specifically positioned so as to reduce the proportion of vertical images of the filament in the beam formed. There is thus obtained at the focal plane of the lens a flatter light spot, facilitating the correction work to be carried out by the glass. However, the light output of the projector is further reduced, and the width of the beam before the lens remains limited.

On connaît également par le document FR-A-2 554 546 un projecteur du même type, dans lequel le miroir est une sorte d'ellipsoïde aplati, s'appuyant verticalement sur une ellipse dont un foyer intérieur est sur la source et dont un foyer extérieur est au voisinage du plan focal de la lentille, et s'appuyant horizontalement sur une ellipse différente, dont le foyer intérieur est également sur la source mais dont le foyer extérieur est situé en avant du plan focal précité.Document FR-A-2 554 546 also discloses a projector of the same type, in which the mirror is a kind of flattened ellipsoid, resting vertically on an ellipse with an interior focus on the source and with a focus exterior is in the vicinity of the focal plane of the lens, and resting horizontally on a different ellipse, the interior focus of which is also on the source but the exterior focus of which is located in front of the abovementioned focal plane.

De la sorte, on assure au niveau du plan focal et du masque un pré-étalement horizontal de la lumière, qui continue cenpendant à converger fortement dans la région du plan focal.In this way, a horizontal pre-spreading of the light is ensured at the focal plane and the mask, which continues to converge strongly in the region of the focal plane.

Cette solution connue est cependant limitée en ce que la répartition horizontale de la concentration de lumière au niveau du masque, ou plus généralement du plan focal de la lentille, est entièrement figée. En conséquence, si l'on souhaite par exemple produire un faisceau de croisement présentant, sensiblement selon l'axe optique, une zone de forte concentration, un travail de correction important, par ailleurs très difficile à réaliser, reste demandé au niveau de la glace, ce qui est désavantageux comme on l'a vu plus haut.This known solution is however limited in that the horizontal distribution of the light concentration at the level of the mask, or more generally of the focal plane of the lens, is entirely fixed. Consequently, if it is desired, for example, to produce a passing beam having, substantially along the optical axis, a zone of high concentration, significant correction work, in addition very difficult to carry out, remains requested at the level of the ice, which is disadvantageous as we saw above.

On connaît par ailleurs par le document EP-A-0 254 746, qui correspond au préambule de la revendication 1, un projecteur de type elliptique dans lequel le miroir est conformé de manière à donner à la tache lumineuse produite à son deuxième former une certaine largeur. Cependant, la solution technique enseignée par ce document consiste à concevoir le miroir facette par facette, ce qui est à la fois coûteux et délicat. En particulier, la réalisation du moule destiné à la fabrication du miroir est complexe et demande une technique d'usinage très élaborée. En outre du fait des ruptures de pente entre les facettes, le faisceau risque de présenter des ruptures de pente.Also known from document EP-A-0 254 746, which corresponds to the preamble of claim 1, an elliptical type projector in which the mirror is shaped so as to give the light spot produced at its second form a certain width. However, the technical solution taught by this document consists in designing the mirror facet by facet, which is both expensive and delicate. In particular, the production of the mold intended for the manufacture of the mirror is complex and requires a very sophisticated machining technique. In addition, due to the slope breaks between the facets, the beam risks presenting slope breaks.

On connaît enfin par le document EP-A-0 153 485 un projecteur dans leque on a également cherché à réaliser une tache lumineuse large au niveau du second foyer d'un miroir du genre elliptique. Mais là encore, le miroir est conçu de façon discrète, bande par bande, avec en conséquence les mêmes inconvénients.Finally, document EP-A-0 153 485 discloses a projector in which an attempt has also been made to produce a large light spot at the second focal point of a mirror of the elliptical type. But here again, the mirror is designed discreetly, strip by strip, with consequently the same drawbacks.

L'invention vise à pallier ces inconvénients de la technique antérieure, et à proposer un projecteur de véhicule automobile de type elliptique dans lequel un faisceau large puisse être obtenu avec un miroir de forme généralement lisse et sans rupture de pente. Elle propose à cet effet un projecteur tel que défini dans la revendication 1.The invention aims to overcome these drawbacks of the prior art, and to provide a motor vehicle headlight of the elliptical type in which a wide beam can be obtained with a mirror of generally smooth shape and without breaking the slope. To this end, it proposes a projector as defined in claim 1.

Des aspects préférés de ce projecteur sont définis dans les sous-revendications.Preferred aspects of this projector are defined in the subclaims.

D'autres aspects, buts et avantages de la présente invention apparaîtront mieux à la lecture de la description détaillée suivante de formes de réalisation préférées de celle-ci, donnée à titre d'exemple et faite en référence aux dessins annexés, sur lesquels :

  • la figure 1 est une vue en coupe horizontale axiale schématique d'un projecteur de croisement pourvu d'un miroir du genre elliptique et de tracés de rayons lumineux illustrant le principe de la présente invention,
  • la figure 2 est une vue en projection sur un plan vertical d'une section verticale désaxée du projecteur de la figure 1 et de tracés de rayons associés,
  • les figures 3a et 3b illustrent respectivement, par des ensembles de courbes isolux, la répartition de la lumière dans le plan du masque avec un miroir ellipsoïdal traditionnel et avec un miroir selon la présente invention, respectivement,
  • la figure 4 illustre l'image obtenue sur un écran de projection avec le projecteur des figures 1 et 2, équipé d'une glace lisse,
  • la figure 5 est une vue en coupe horizontale axiale d'un miroir du genre elliptique selon une variante de réalisation de la présente invention,
  • la figure 5bis est une vue à échelle agrandie d'une partie de la figure 5, et
  • la figure 6 illustre l'image obtenue sur un écran de projection avec le projecteur de la figure 5, équipé d'une glace lisse.
Other aspects, aims and advantages of the present invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of example and made with reference to the appended drawings, in which:
  • FIG. 1 is a schematic axial horizontal sectional view of a dipped beam projector provided with a mirror of the elliptical type and with traces of light rays illustrating the principle of the present invention,
  • FIG. 2 is a view in projection on a vertical plane of an offset vertical section of the projector of FIG. 1 and of associated ray tracings,
  • FIGS. 3a and 3b respectively illustrate, by sets of isolux curves, the distribution of light in the plane of the mask with a traditional ellipsoidal mirror and with a mirror according to the present invention, respectively,
  • FIG. 4 illustrates the image obtained on a projection screen with the projector of FIGS. 1 and 2, equipped with a smooth lens,
  • FIG. 5 is a view in axial horizontal section of a mirror of the elliptical type according to an alternative embodiment of the present invention,
  • FIG. 5bis is an enlarged view of part of FIG. 5, and
  • Figure 6 illustrates the image obtained on a projection screen with the projector of Figure 5, equipped with a smooth glass.

En référence tout d'abord aux figures 1 et 2, on a représenté un projecteur qui comprend une source lumineuse 10 de petites dimensions, telle que le filament d'une lampe à incandescence ou l'arc d'une lampe à décharge, un miroir 20 de récupération et de concentration du flux lumineux émis par la source, un masque 30 placé dans une position bien déterminée en avant du miroir 20 et destiné à former, par occultation d'une partie du rayonnement incident, une image lumineuse de forme et de répartition lumineuse déterminées convenant à un faisceau de croisement, une lentille convergente 40, par exemple une lentille plan-convexe, dont le plan focal est situé au niveau du masque 30, et enfin une glace de fermeture 50 de préférence lisse ou faiblement déviatrice.Referring firstly to Figures 1 and 2, there is shown a projector which comprises a light source 10 of small dimensions, such as the filament of an incandescent lamp or the arc of a discharge lamp, a mirror 20 for recovering and concentrating the light flux emitted by the source, a mask 30 placed in a well-determined position in front of the mirror 20 and intended to form, by occultation of part of the incident radiation, a luminous image of shape and determined light distribution suitable for a passing beam, a converging lens 40, for example a plano-convex lens, the focal plane of which is situated at the level of the mask 30, and finally a closing glass 50 preferably smooth or slightly deflecting.

Lorsque, selon la technique antérieure, le miroir 20 est du genre ellipsoïdal avec deux foyers situés sur son axe, la source 10 est placée au voisinage du premier foyer tandis que le masque 30 est placé au voisinage du second foyer, où converge la lumière renvoyée par le miroir.When, according to the prior art, the mirror 20 is of the ellipsoidal genus with two focal points situated on its axis, the source 10 is placed in the vicinity of the first focal point while the mask 30 is placed in the vicinity of the second focal point, where the reflected light converges by the mirror.

Selon la présente invention, le miroir comporte au moins une zone telle que le point de convergence du rayonnement, en projection dans un plan horizontal, c'est-à-dire le point qui correspond au deuxième foyer d'un ellipsoïde, varie à mesure que l'on s'écarte latéralement de l'axe optique du miroir.According to the present invention, the mirror comprises at least one zone such that the point of convergence of the radiation, in projection in a horizontal plane, that is to say the point which corresponds to the second focus of an ellipsoid, varies as that we move laterally from the optical axis of the mirror.

La figure 1 montre que le miroir 20 possède une zone centrale ou zone de fond 21 qui est caractérisée optiquement par un premier foyer FR, sur lequel la source 10 est placée, et par un second foyer FS, fixe, vers lequel l'ensemble du rayonnement réfléchi par cette zone 21 converge. Ce foyer FS est situé dans le plan du masque 30 et de préférence au voisinage d'une arête 31 dudit masque elle-même destinée à définir une coupure du faisceau engendré.FIG. 1 shows that the mirror 20 has a central zone or bottom zone 21 which is optically characterized by a first focal point FR, on which the source 10 is placed, and by a second focal point FS, fixed, towards which the whole of the radiation reflected by this zone 21 converges. This focal point FS is located in the plane of the mask 30 and preferably in the vicinity of an edge 31 of said mask itself intended to define a cut-off of the generated beam.

En section verticale, cette zone 21 possède un comportement semblable, avec les mêmes foyers FR et FS. Cette zone 21 peut donc être constituée par une portion d'ellipsoïde de révolution de foyers FR et FS.In vertical section, this zone 21 has a similar behavior, with the same foci FR and FS. This zone 21 can therefore be constituted by a portion of ellipsoid of revolution of FR and FS homes.

Cette zone 21 a pour objet de créer au niveau du plan focal de la lentille 40 une tache centrale relativement concentrée.The purpose of this zone 21 is to create a relatively concentrated central spot at the focal plane of the lens 40.

Le miroir 20 comporte également deux zones latérales 22a et 22b réalisées selon la présente invention.The mirror 20 also comprises two lateral zones 22a and 22b produced according to the present invention.

Comme on l'observe sur la figure 1, les limites intérieures des deux zones 22a et 22b se trouvent à une cote latérale y = +ymin ou y = -ymin respectivement, la largeur de la zone centrale 21 étant égale à 2.ymin.As can be seen in FIG. 1, the internal limits of the two zones 22a and 22b are at a lateral dimension y = + y min or y = -y min respectively, the width of the central zone 21 being equal to 2. y min .

Bien entendu, on pourra prévoir dans une variante non illustrée deux valeurs limites différentes à gauche et à droite, notées +ymin1 et -ymin2.Of course, in a variant not shown, two different limit values can be provided on the left and on the right, denoted + y min1 and -y min2 .

On va maintenant décrire le comportement optique de la zone latérale 22a située du côté des y positifs. A la cote ymin, le rayonnement issu de la source 10 converge vers le foyer FS mentionné plus haut. Mais à mesure que l'on s'éloigne de ymin dans le sens des y positifs (vers le bas sur la figure 1), on constate que le point de convergence, sur l'axe optique Ox passant par les foyers FR et FS, s'éloigne progressivement du point FS vers l'avant du projecteur. On note Fc le foyer horizontal courant à la cote yc.We will now describe the optical behavior of the lateral zone 22a located on the positive y side. At the dimension y min , the radiation from the source 10 converges towards the focal point FS mentioned above. But as we move away from ymin in the positive y direction (down in Figure 1), we see that the point of convergence, on the optical axis Ox passing through the focal points FR and FS, gradually moves away from the point FS towards the front of the projector. We denote by Fc the current horizontal focus at dimension y c .

La zone 22a s'étend latéralement jusqu'à une limite notée ymax. A cette cote, le foyer horizontal courant Fc atteint une position extrême avant sur l'axe Ox, notée FT.The zone 22a extends laterally up to a limit denoted y max . At this level, the current horizontal focus Fc reaches an extreme forward position on the axis Ox, denoted FT.

La relation entre la cote yc, variant entre ymin et ymax, et le foyer horizontal courant Fc peut être une relation monotone quelconque, par exemple une relation linéaire. Des relations non linéaires sont bien entendu envisageables.The relation between the dimension yc, varying between y min and y max , and the current horizontal focus Fc can be any monotonic relation, for example a linear relation. Non-linear relationships are of course conceivable.

En projection dans le plan vertical, la zone 22a se comporte différemment, c'est-à-dire que, quelle que soit la cote en y d'une tranche verticale du miroir, la convergence dans le plan vertical se produit de préférence sur la droite D parallèle à y'y et passant par le foyer FS ou au voisinage de cette droite. Ce comportement est illustré sur la figure 2.In projection in the vertical plane, the zone 22a behaves differently, that is to say that, whatever the dimension in y of a vertical section of the mirror, the convergence in the vertical plane preferably occurs on the line D parallel to y'y and passing through the focal point FS or in the vicinity of this line. This behavior is illustrated in Figure 2.

La zone latérale opposée 22b se comporte en l'espèce symétriquement de la zone 22a par rapport à l'axe optique 0x, et ce comportement ne sera pas repris ici.The opposite lateral zone 22b behaves symmetrically in this case from the zone 22a with respect to the optical axis 0x, and this behavior will not be repeated here.

Ainsi l'on comprend que les zones latérales 22a et 22b du miroir coopèrent pour engendrer dans le plan focal de la lentille 40 une tache lumineuse qui est verticalement peu épaisse, dans la mesure où la convergence verticale s'effectue toujours au voisinage de la droite D susmentionnée. En théorie, pour un miroir optiquement parfait, cette épaisseur n'est fonction que des dimensions de la source 10.Thus it is understood that the lateral zones 22a and 22b of the mirror cooperate to generate in the focal plane of the lens 40 a light spot which is vertically little thick, insofar as the vertical convergence always takes place in the vicinity of the line D mentioned above. In theory, for an optically perfect mirror, this thickness depends only on the dimensions of the source 10.

On comprend également que, horizontalement, le décalage progressif des points de convergence Fc vers l'avant par rapport à FS donne à la tache lumineuse engendrée par les zones 22a, 22b une forme étalée latéralement.It is also understood that, horizontally, the progressive shift of the points of convergence Fc towards the front relative to FS gives the light spot generated by the zones 22a, 22b a form spread laterally.

Le miroir 20 selon l'invention permet donc d'engendrer au niveau du masque 30 une tache lumineuse dont une partie est une tache centrale concentrée, destinée à donner au faisceau projeté sa portée, et dont une autre partie est une tache large et peu épaisse, destinée à donner au faisceau sa largeur. On observe également que, dans la mesure où les zones 22a, 22b n'accroissent sensiblement pas la hauteur verticale de la tache par rapport au cas d'un ellipsoïde de révolution, le rendement lumineux n'est pas dégradé car on n'accroît sensiblement pas la proportion de lumière occultée par le masque 30.The mirror 20 according to the invention therefore makes it possible to generate at the level of the mask 30 a light spot of which a part is a concentrated central spot, intended to give the projected beam its range, and of which another part is a wide and not very thick spot. , intended to give the beam its width. It is also observed that, insofar as the zones 22a, 22b do not appreciably increase the vertical height of the spot relative to the case of an ellipsoid of revolution, the light output is not degraded because it does not appreciably increase not the proportion of light obscured by the mask 30.

On va maintenant définir mathématiquement un exemple de surface réfléchissante d'un miroir ayant les propriétés décrites ci-dessus.We will now mathematically define an example of a reflecting surface of a mirror having the properties described above.

La section horizontale axiale (z=0) de la surface est la suivante : x₀=u(y₀)=1/2[F₀+G₀(y₀)].[1+√[(F₀.G₀(y₀)-y₀²)/F₀G₀(y₀)]

Figure imgb0001

où

  • · x₀ et y₀ sont les coordonnées cartésiennes des points de la section de la surface dans le plan z=0,
  • · Fo est la cote selon Ox du foyer FR,
  • · G₀(|y₀|)=g₀ si |y₀|≦ymin et
    G₀(|y₀|)=g₀+h(|y₀|) si ymin<|y₀|≦ymax
  • · g₀ est la cote selon Ox du foyer FS
  • · h(|y₀|) est une fonction monotone, en l'espèce croissante, telle que h(|y min |)=0 et
    Figure imgb0002
     h(|y max |)=e
    Figure imgb0003
  • · e est l'écart positif sur l'axe Ox entre les positions des foyers FS et FT.
The axial horizontal section (z = 0) of the surface is as follows: x₀ = u (y₀) = 1/2 [F₀ + G₀ (y₀)]. [1 + √ [(F₀.G₀ (y₀) -y₀²) / F₀G₀ (y₀)]
Figure imgb0001
or
  • · X₀ and y₀ are the Cartesian coordinates of the points of the section of the surface in the plane z = 0,
  • · F o is the dimension according to Ox of the hearth FR,
  • · G₀ (| y₀ |) = g₀ if | y₀ | ≦ y min and
    G₀ (| y₀ |) = g₀ + h (| y₀ |) if y min <| y₀ | ≦ y max
  • · G₀ is the dimension according to Ox of the FS hearth
  • · H (| y₀ |) is a monotonic function, in the increasing case, such that h (| y min |) = 0 and
    Figure imgb0002
     h (| y max |) = e
    Figure imgb0003
  • · E is the positive deviation on the Ox axis between the positions of the FS and FT foci.

L'équation de la surface réfléchissante en coordonnées cartésiennes dans le repère (0,x,y,z) tel qu'illustré sur les figures 1 et 2 peut s'exprimer comme suit : fg[L²/(1+B²)-fg(f+g)[L/√(1+B²)]+(f²+g²)z/4 = 0

Figure imgb0004

où

  • · L = x+By+C
  • · f = (F₀+C)/√(1+B²)
  • · g = g₀F₀/f
  • · B = ∂u(y)/∂y et
  • · C = u(y)-yB
The equation of the reflecting surface in Cartesian coordinates in the coordinate system (0, x, y, z) as illustrated in Figures 1 and 2 can be expressed as follows: fg [L² / (1 + B²) -fg (f + g) [L / √ (1 + B²)] + (f² + g²) z / 4 = 0
Figure imgb0004
or
  • L = x + By + C
  • · F = (F₀ + C) / √ (1 + B²)
  • G = g₀F₀ / f
  • · B = ∂u (y) / ∂y and
  • · C = u (y) -yB

On peut démontrer mathématiquement qu'avec la surface définie ci-dessus, les points de convergence verticale, qui doivent être aussi proches que possible du plan focal PF, évoluent selon la courbe CE représentée en tiretés sur la figure 1. L'écart par rapport à la droite idéale D reste cependant tout à fait acceptable.We can demonstrate mathematically that with the surface defined above, the vertical convergence points, which must be as close as possible to the focal plane PF, evolve according to the curve CE shown in dashed lines in FIG. 1. The deviation from to the ideal right D remains however entirely acceptable.

En référence maintenant aux figures 3a et 3b, on a représenté à la même échelle d'une part la tache lumineuse obtenue dans le plan focal de la lentille 40 avec un miroir en forme d'ellipsoïde de révolution (figure 3a) et d'autre part la tache lumineuse obtenue avec un miroir selon la présente invention (figure 3b) . Dans les deux cas, la source lumineuse avait la géométrie d'un cylindre disposé axialement sur l'axe Ox.Referring now to Figures 3a and 3b, there is shown on the same scale on the one hand the light spot obtained in the focal plane of the lens 40 with a mirror in the shape of an ellipsoid of revolution (Figure 3a) and on the other share the light spot obtained with a mirror according to the present invention (Figure 3b). In both cases, the light source had the geometry of a cylinder arranged axially on the axis Ox.

Sur la figure 3a, on observe une tache de contour général circulaire, qui découle de la forme de révolution du miroir.In FIG. 3a, a spot of general circular outline is observed, which follows from the shape of revolution of the mirror.

On observe sur la figure 3b que la tache présente une concentration centrale marquée et en même temps une largeur importante, sans être plus haute verticalement que celle de la figure 3a.It can be seen in FIG. 3b that the spot has a marked central concentration and at the same time a large width, without being higher vertically than that of FIG. 3a.

On comprend donc qu'en occultant une partie de la tache de la figure 3b avec le masque 30 (zone hachurée), on va obtenir un faisceau coupé (en l'occurrence un faisceau de croisement aux normes européennes) tout à fait satisfaisant.It is therefore understood that by obscuring part of the spot in FIG. 3b with the mask 30 (hatched area), we will obtain a cut beam (in this case a passing beam according to European standards) quite satisfactory.

La figure 4 illustre par un ensemble de courbes isolux Ci sur un écran de projection normalisé l'allure du faisceau obtenu, sans intervention de la glace de fermeture.FIG. 4 illustrates by a set of isolux curves Ci on a standardized projection screen the appearance of the beam obtained, without the intervention of the closing glass.

On observe la présence d'une tache de concentration centrale TC bien marquée, et une bonne largeur du faisceau selon les deux demi-coupures h'H et Hc.One observes the presence of a spot of central concentration TC well marked, and a good width of the beam according to the two half-cuts h'H and Hc.

On remarque également que le faisceau est peu épais, ce qui permet de ne pas éclairer la route à trop grande proximité du véhicule.We also note that the beam is thin, which allows not to light the road too close to the vehicle.

Maintenant en référence aux figures 5 et 5bis, on a représenté une variante de réalisation d'un projecteur selon la présente invention, dont le miroir comporte une zone centrale 21 en forme d'ellipsoïde de révolution et deux zones latérales 22a et 22b réalisées comme décrit plus haut et, entre ladite zone centrale et les zones latérales, de zones intermédiaires formant stries, respectivement 23a et 23b. Ces zones intermédiaires sont réalisées par déformation locale par rapport au miroir de la figure 1, de manière à disperser de façon importante les points de convergence horizontale sur Ox obtenus pour tranche verticale des zones intermédiaires.Now with reference to FIGS. 5 and 5a, an alternative embodiment of a projector according to the present invention has been shown, the mirror of which has a central zone 21 in the form of an ellipsoid of revolution and two lateral zones 22a and 22b produced as described above and, between said central zone and the lateral zones, intermediate zones forming striations, respectively 23a and 23b. These intermediate zones are produced by local deformation with respect to the mirror of FIG. 1, so as to disperse significantly the points of horizontal convergence on Ox obtained for vertical section of the intermediate zones.

De préférence, la convergence verticale du miroir est la même que dans le cas des figures 1 et 2, c'est-à-dire que la lumière converge verticalement de préférence au voisinage du plan focal de la lentille pour tous les points du miroir.Preferably, the vertical convergence of the mirror is the same as in the case of FIGS. 1 and 2, that is to say that the light converges vertically preferably in the vicinity of the focal plane of the lens for all the points of the mirror.

Les zones intermédiaires 23a et 23b se raccordent de préférence de façon continue, et le cas échéant dérivable, avec les zones voisines 21 et respectivement 22a, 22b.The intermediate zones 23a and 23b are preferably connected continuously, and if necessary differentiable, with the neighboring zones 21 and 22a, 22b respectively.

Par exemple, on peut utiliser pour la génératrice horizontale des zones intermédiaires 23a, 23b l'équation d'une conique, et plus particulièrement l'équation indiquée ci-dessous, qui est celle d'un cercle : x₀ = u(y₀) = √(r²-(y₀-y c )²) + x c
où

  • · yo varie entre les cotes limites horizontales, respectivement ±y₃₁ et ±y₃₂, des zones 23a et 23b,
  • · xc et yc sont des paramètres fixes, à savoir les coordonnées du centre du cercle, choisis en fonction de l'équation u(y₀) pour les zones 21 et 22a, 22b de manière à assurer le raccordement continu tel qu'indiqué plus haut, et
  • · r est un paramètre, à savoir le rayon du cercle, permettant de régler l'ampleur de la dispersion des points de convergence horizontale sur Ox par les zones intermédiaires, ou en d'autres termes la largeur de la tache engendrée par les seules zones intermédiaires.
For example, one can use for the horizontal generator of intermediate zones 23a, 23b the equation of a conic, and more particularly the equation indicated below, which is that of a circle: x₀ = u (y₀) = √ (r²- (y₀-y vs ) ²) + x vs
or
  • · Y o varies between the horizontal limit dimensions, respectively ± y₃₁ and ± y₃₂, of zones 23a and 23b,
  • · X c and y c are fixed parameters, namely the coordinates of the center of the circle, chosen according to the equation u (y₀) for the zones 21 and 22a, 22b so as to ensure the continuous connection as indicated higher, and
  • · R is a parameter, namely the radius of the circle, making it possible to adjust the extent of the dispersion of the points of horizontal convergence on Ox by the intermediate zones, or in other words the width of the spot generated by the only zones intermediaries.

L'équation cartésienne en x,y,z de la surface réfléchissante du miroir reste identique à l'équation (2) présentée plus haut, la mofidication locale de la fonction u(y₀) se traduisant dans cette équation par la présence de deux stries orientées dans des plans verticaux parallèles à l'axe optique Ox de part et d'autre de celui-ci.The Cartesian equation in x, y, z of the reflecting surface of the mirror remains identical to equation (2) presented above, the local modification of the function u (y₀) resulting in this equation by the presence of two streaks oriented in vertical planes parallel to the optical axis Ox on either side of it.

Bien entendu, on peut multiplier le nombre de stries à souhait.Of course, you can multiply the number of streaks as desired.

Dans une première application des stries décrites ci-dessus, on les place dans la région du fond du miroir. On réalise de cette manière un étalement important en direction latérale des grandes images verticales formées par cette région de fond dans le cas où la source est disposée axialement, pour ainsi diminuer l'épaisseur du faisceau dans l'axe, et ne pas éclairer trop fortement la route à proximité du véhicule.In a first application of the streaks described above, they are placed in the region of the bottom of the mirror. This produces a large spread in the lateral direction of the large vertical images formed by this background region in the case where the source is arranged axially, thereby reducing the thickness of the beam in the axis, and not illuminating too strongly. the road near the vehicle.

Dans une deuxième application des stries, particulièrement utile dans le cas où la source est l'arc d'une lampe à décharge, extrêmement intense, on paramètre les stries de manière à respecter des niveaux d'éclairement maximal autorisé par les règlements, tout particulièrement dans la région située à gauche de la tache de concentration au-dessous de la demi-coupure horizontale hH.In a second application of the streaks, particularly useful in the case where the source is the arc of an extremely intense discharge lamp, the streaks are configured so as to respect the maximum levels of illumination authorized by the regulations, in particular in the region to the left of the concentration spot below the horizontal half-cut hH.

La figure 6 illustre, par des courbes isocandéla C'i sur un écran de projection normalisé, l'allure du faisceau obtenu avec un projecteur équipé du miroir de la figure 5, sans intervention de la glace. On observe que l'épaisseur du faisceau dans l'axe (au-dessous du point H) est sensiblement réduite par rapport au cas de la figure 4, du fait qu'une certaine proportion de grandes images verticales ou peu inclinées par rapport à la verticale ont été dispersées latéralement.FIG. 6 illustrates, by isocandela curves C'i on a standardized projection screen, the shape of the beam obtained with a projector equipped with the mirror of FIG. 5, without the intervention of the glass. It is observed that the thickness of the beam in the axis (below the point H) is appreciably reduced compared to the case of FIG. 4, because a certain proportion of large vertical images or slightly inclined with respect to the vertical were scattered laterally.

Bien que l'on ait décrit l'invention dans le cadre d'un projecteur de croisement de type européen, il est clair que l'invention s'applique aussi bien à d'autres types de projecteurs, notamment des projecteurs de route ou anti-brouillard.Although the invention has been described in the context of a European type low beam headlamp, it is clear that the invention applies equally to other types of headlamps, in particular road or anti headlamps -fog.

Dans le cas d'un projecteur de route, on ne prévoit généralement pas de masque 30, si bien qu'avec le projecteur des figures 1 et 2, la configuration photométrique obtenue correspondra au courbes de la figure 3b sans occultation.In the case of a road headlamp, a mask 30 is generally not provided, so that with the headlamp in FIGS. 1 and 2, the configuration photometric obtained will correspond to the curves of figure 3b without occultation.

Dans le cas d'un projecteur anti-brouillard, on prévoit un masque doté d'une arête horizontale rectiligne.In the case of a fog light, a mask is provided with a rectilinear horizontal edge.

Par ailleurs, bien que dans le cas des figures 1 et 2 on prévoit des zones 22a et 22b qui décalent le point de convergence horizontale vers l'avant par rapport au plan focal de la lentille 40 à mesure que l'on s'éloigne latéralement de l'axe 0x, on peut bien entendu prévoir que ces points de convergence se rapprochent du plan focal PF lorsque l'on s'éloigne de l'axe optique. Cette approche est d'ailleurs préférée dans le cas d'un faisceau antibrouillard.Furthermore, although in the case of FIGS. 1 and 2, zones 22a and 22b are provided which shift the point of horizontal convergence forwards relative to the focal plane of the lens 40 as one moves away laterally of the axis 0x, it can of course be provided for these points of convergence to approach the focal plane PF when one moves away from the optical axis. This approach is moreover preferred in the case of an anti-fog beam.

Concrètement, la variante ci-dessus peut être facilement mise en oeuvre en utilisant pour la fonction h(|y₀|) une fonction monotone décroissante, linéaire ou non, variant entre e et zéro au lieu de varier entre zéro et e.Concretely, the above variant can be easily implemented by using for the function h (| y₀ |) a decreasing monotonic function, linear or not, varying between e and zero instead of varying between zero and e .

Bien entendu, la présente invention n'est nullement limitée aux formes de réalisation décrites ci-dessus et représentées sur les dessins, et l'homme de l'art saura y apporter toute variante ou modification conforme à son esprit.Of course, the present invention is in no way limited to the embodiments described above and shown in the drawings, and a person skilled in the art will know how to make any variant or modification in accordance with his spirit.

Claims (12)

Projecteur de véhicule automobile, du type susceptible d'engendrer un faisceau lumineux de configuration donnée et comportant une source lumineuse (10), un miroir (20) du genre elliptique au voisinage d'un premier foyer duquel est située la source lumineuse, une lentille (40) placée en avant du miroir et une glace de fermeture (50) placée en avant de la lentille, le miroir étant apte à engendrer dans la région d'un second foyer une tache lumineuse étalée en largeur,
caractérisé en ce que le miroir comporte dans au moins une zone (22a, 22b) une surface réfléchissante généralement lisse et sans rupture de pente, dont chaque tranche horizontale réfléchit le rayonnement issu de la source vers une multitude de points de convergence horizontale (Fc) situés à des distances horizontales (h(yc)), mesurées selon l'axe optique (Ox) du projecteur par rapport à un plan focal (PF) de la lentille, qui varient en fonction de l'écartement (yc) du lieu de réflexion considéré par rapport à l'axe optique du miroir, et dont chaque tranche verticale réfléchit le rayonnement issu de la source vers des points de convergence verticale situés à proximité dudit plan focal de la lentille,
et en ce que le glace (50) est essentiellement lisse ou faiblement déviatrice en direction horizontale.Motor vehicle headlamp, of the type capable of generating a light beam of given configuration and comprising a light source (10), a mirror (20) of the elliptical type in the vicinity of a first focal point of which the light source is situated, a lens (40) placed in front of the mirror and a closing glass (50) placed in front of the lens, the mirror being able to generate in the region of a second focus a light spot spread in width,
characterized in that the mirror comprises in at least one zone (22a, 22b) a generally smooth reflecting surface without any break in slope, each horizontal slice of which reflects the radiation coming from the source towards a multitude of horizontal convergence points (Fc) located at horizontal distances (h (y c )), measured along the optical axis (Ox) of the projector relative to a focal plane (PF) of the lens, which vary according to the spacing (y c ) of the place of reflection considered with respect to the optical axis of the mirror, and each vertical section of which reflects the radiation coming from the source towards points of vertical convergence situated near said focal plane of the lens,
and in that the glass (50) is essentially smooth or slightly deflecting in the horizontal direction. Projecteur selon la revendication 1, caractérisé en ce que, dans au moins une autre zone (21) du miroir, chaque tranche horizontale de la surface réfléchissante réfléchit le rayonnement issu de la source vers un point de convergence horizontale invariable (FS), cette zone présentant, dans un plan horizontal (xOy) contenant la source lumineuse, un profil de surface réfléchissante elliptique.Projector according to claim 1, characterized in that, in at least one other zone (21) of the mirror, each horizontal slice of the reflecting surface reflects the radiation coming from the source towards an invariable horizontal convergence point (FS), this zone having, in a horizontal plane (xOy) containing the light source, an elliptical reflecting surface profile. Projecteur selon la revendication 2, caractérisé en ce que ladite autre zone est une zone de fond (21) et il est prévu deux premières zones (22a, 22b) situées de part et d'autre de la zone de fond.Projector according to claim 2, characterized in that said other zone is a bottom zone (21) and there are provided two first zones (22a, 22b) located on either side of the bottom zone. Projecteur de véhicule automobile selon la revendication 1, 2 ou 3, caractérisé en ce qu'il comprend en outre un masque (30) situé au voisinage du plan focal (PF) de la lentille et dont un bord définit une coupure nette du faisceau engendré, en ce que les points de convergence verticale sont situés au voisinage dudit bord du masque et en ce qu'au moins une partie des points de convergence horizontale variable (Fc) sont situés en avant du masque.Motor vehicle headlight according to claim 1, 2 or 3, characterized in that it further comprises a mask (30) situated in the vicinity of the focal plane (PF) of the lens and one edge of which defines a clear cut in the generated beam , in that the vertical convergence points are located in the vicinity of said edge of the mask and in that at least a portion of the variable horizontal convergence points (Fc) are located in front of the mask. Projecteur selon la revendication 4, destiné à engendrer un faisceau de croisement délimité par une coupure nette et comportant une zone de concentration disposée essentiellement centralement, caractérisé en ce qu'un point de convergence horizontale variable (Fc) est d'autant plus éloigné du plan focal (PF) de la lentille que le lieu de réflexion considéré est éloigné latéralement de l'axe optique (Ox).Projector according to claim 4, intended to generate a passing beam delimited by a clear cut and comprising a concentration zone arranged essentially centrally, characterized in that a variable horizontal convergence point (Fc) is all the more distant from the plane focal (PF) of the lens that the considered place of reflection is laterally distant from the optical axis (Ox). Projecteur selon la revendication 4, destiné à engendrer un faisceau anti-brouillard délimité par une coupure et présentant un éclairement généralement homogène sur une largeur étendue, caractérisé en ce qu'un point de convergence horizontale variable (Fc) est d'autant plus proche du plan focal (PF) de la lentille que le lieu de réflexion considéré est éloigné latéralement de l'axe optique (Ox).Projector according to claim 4, intended to generate an anti-fog beam delimited by a cut and having a generally homogeneous illumination over an extended width, characterized in that a variable horizontal point of convergence (Fc) is all the closer to the focal plane (PF) of the lens that the point of reflection considered is laterally distant from the optical axis (Ox). Projecteur selon la revendication 5 ou 6, caractérisé en ce que la position du point de convergence horizontale variable (Fc) en fonction de la cote latérale (y0) du lieu de réflexion par rapport à l'axe optique est une loi continue.Projector according to claim 5 or 6, characterized in that the position of the variable horizontal point of convergence (Fc) as a function of the lateral dimension (y0) of the place of reflection relative to the optical axis is a continuous law. Projecteur selon la revendication 7, caractérisé en ce que la position du point de convergence horizontale variable (Fc) en fonction de la cote latérale (y0) du lieu de réflexion par rapport à l'axe optique est une loi linéaire.Projector according to claim 7, characterized in that the position of the variable horizontal point of convergence (Fc) as a function of the lateral dimension (y0) of the place of reflection relative to the optical axis is a linear law. Projecteur selon l'une des revendications 1 à 5, caractérisé en ce que la surface réfléchissante du miroir (20) est définie au moins approximativement par les équations suivantes : a) équation de la section de la surface dans un plan horizontal axial (0,x,y) : x₀=u(y₀)=1/2[F₀+G₀(y₀)].[1+√[(F₀.G₀(y₀)-y₀²)/F₀G₀(y₀)]
Figure imgb0006
 où · x₀ et y₀ sont les coordonnées cartésiennes des points de la section de la surface dans le plan z=0, · Fo est la cote selon Ox du foyer FR, · G₀(|y₀|)=g₀ si |y₀|≦ymin et
G₀(|y₀|)=g₀+h(|y₀|) si ymin<|y₀|≦ymax · g₀ est la cote selon Ox du foyer FS · h(|y₀|) est une fonction monotone, en l'espèce croissante, telle que h(|y min |)=0 et
Figure imgb0007
 h(|y max |)=e
Figure imgb0008
 · e est l'écart positif sur l'axe Ox entre les positions des foyers FS et FT, b) équation de la surface dans le repère orthonormé (0,x,y,z) : fg[L²/(1+B²)-fg(f+g)[L/√(1+B²)]+(f²+g²)z/4 = 0
Figure imgb0009
 où · L = x+By+C · f = (F₀+C)/√(1+B²) · g = g₀F₀/f · B = ∂u(y)/∂y et · C = u(y)-yB Projector according to one of Claims 1 to 5, characterized in that the reflecting surface of the mirror (20) is defined at least approximately by the following equations: a) equation of the cross-section of the surface in an axial horizontal plane (0, x, y): x₀ = u (y₀) = 1/2 [F₀ + G₀ (y₀)]. [1 + √ [(F₀.G₀ (y₀) -y₀²) / F₀G₀ (y₀)]
Figure imgb0006
 or · X₀ and y₀ are the Cartesian coordinates of the points of the section of the surface in the plane z = 0, · F o is the dimension according to Ox of the hearth FR, · G₀ (| y₀ |) = g₀ if | y₀ | ≦ y min and
G₀ (| y₀ |) = g₀ + h (| y₀ |) if y min <| y₀ | ≦ y max · G₀ is the dimension according to Ox of the FS hearth · H (| y₀ |) is a monotonic function, in the increasing case, such that h (| y min |) = 0 and
Figure imgb0007
 h (| y max |) = e
Figure imgb0008
 · E is the positive deviation on the Ox axis between the positions of the FS and FT foci, b) equation of the surface in the orthonormal coordinate system (0, x, y, z): fg [L² / (1 + B²) -fg (f + g) [L / √ (1 + B²)] + (f² + g²) z / 4 = 0
Figure imgb0009
 or L = x + By + C · F = (F₀ + C) / √ (1 + B²) G = g₀F₀ / f · B = ∂u (y) / ∂y and · C = u (y) -yB Projecteur selon la revendication 9, caractérisé en ce que les points de convergence verticale suivent une courbe continue (CE) située à proximité du plan focal (PF) de la lentille et en avant de celui-ci.Projector according to claim 9, characterized in that the vertical convergence points follow a continuous curve (CE) located near the focal plane (PF) of the lens and in front of it. Projecteur selon l'une des revendications 1 à 10, caractérisé en ce que le miroir (20) comporte au moins une strie (23a, 23b) de forme générale bombée se raccordant continûment avec les parties voisines du miroir.Projector according to one of claims 1 to 10, characterized in that the mirror (20) comprises at least one groove (23a, 23b) of generally convex shape connecting continuously with the neighboring parts of the mirror. Projecteur selon la revendication 11, caractérisé en ce que chaque strie (23a, 23b) est disposée au voisinage du fond du miroir (20) pour disperser latéralement de grandes images verticales de la source (10).Projector according to claim 11, characterized in that each stripe (23a, 23b) is arranged in the vicinity of the bottom of the mirror (20) for laterally dispersing large vertical images of the source (10).
EP94400828A 1993-04-15 1994-04-15 Vehicle headlamp with ellipsoidal type light reflector Expired - Lifetime EP0628765B1 (en)

Applications Claiming Priority (2)

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FR9304449 1993-04-15
FR9304449A FR2704044B1 (en) 1993-04-15 1993-04-15 ELLIPTICAL TYPE PROJECTOR FOR MOTOR VEHICLE.

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EP0628765B1 EP0628765B1 (en) 1996-12-18

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2843184A1 (en) 2002-08-05 2004-02-06 Valeo Vision Projector type headlamp, for vehicle, has position of secondary focal point on secondary focal point line such that lateral distance between each secondary focal point and vertical axial plane is increasing then decreasing at least once
EP0923695B2 (en) † 1997-07-11 2013-07-17 Automotive Lighting Reutlingen GmbH Low beam headlamps and high beam headlamps for vehicles

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Publication number Priority date Publication date Assignee Title
DE19602978B4 (en) * 1996-01-27 2007-04-26 Automotive Lighting Reutlingen Gmbh Vehicle headlights
JP3145930B2 (en) * 1996-08-02 2001-03-12 株式会社小糸製作所 Vehicle headlights
FR2773604B1 (en) * 1998-01-09 2000-03-31 Valeo Vision ELLIPTICAL PROJECTOR FOR A MOTOR VEHICLE
FR2777632B1 (en) * 1998-04-20 2000-07-07 Valeo Vision PROJECTOR CAPABLE OF TRANSMITTING BEAMS FOR LEFT OR RIGHT TRAFFIC, FOR MOTOR VEHICLES
FR2789476B1 (en) 1999-02-09 2001-04-27 Valeo Vision ELLIPTICAL PROJECTOR FOR A MOTOR VEHICLE, LIKELY TO TRANSMIT A BEAM WITHOUT CUT
FR2789474B1 (en) 1999-02-09 2001-04-27 Valeo Vision ELLIPTICAL PROJECTOR FOR A MOTOR VEHICLE, CAPABLE OF SELECTIVELY GENERATING ONE OF TWO TYPES OF BEAMS
FR2789475B1 (en) 1999-02-09 2001-04-27 Valeo Vision ELLIPTICAL PROJECTOR FOR A MOTOR VEHICLE CAPABLE OF EMITTING A BEAM WITH IMPROVED PHOTOMETRY CUTTING
FR2793542B1 (en) 1999-05-12 2001-08-17 Valeo Vision ELLIPTICAL PROJECTOR WITH TWO LIGHTING FUNCTIONS FOR A MOTOR VEHICLE
FR2797030B1 (en) 1999-07-30 2001-09-14 Valeo Vision ELLIPTICAL PROJECTOR FOR A MOTOR VEHICLE, CAPABLE OF GENERATING A TWO-FUNCTIONAL LIGHT BEAM
FR2797029B1 (en) 1999-07-30 2001-09-14 Valeo Vision ELLIPTICAL PROJECTOR FOR A MOTOR VEHICLE, CAPABLE OF GENERATING A TWO-FUNCTIONAL LIGHT BEAM
FR2802282B1 (en) 1999-12-09 2002-01-25 Valeo Vision METHOD FOR DEVELOPING A MASK FOR ADAPTING A CROSSING PROJECTOR BEAM TO A DIRECTION OF REVERSE TRAFFIC
FR2809798B1 (en) 2000-05-31 2002-11-29 Valeo Vision METHOD FOR ADAPTING AN ELLIPTICAL PROJECTOR CROSSING BEAM TO A DIRECTION OF REVERSE CIRCULATION, DEVICE, TEMPLATE AND PROJECTOR FOR CARRYING OUT SAID METHOD
FR2810934B1 (en) 2000-07-03 2002-09-13 Valeo Vision ELLIPTICAL PROJECTOR WITH BEAM MODIFICATION BY MOVEMENT OF OPTICAL ELEMENTS

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EP0153485A2 (en) * 1984-02-25 1985-09-04 Hella KG Hueck &amp; Co. Non-dazzling vehicle headlight
EP0254746A1 (en) * 1985-12-27 1988-02-03 Ichikoh Industries Limited Projector-type headlight for vehicles

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EP0153485A2 (en) * 1984-02-25 1985-09-04 Hella KG Hueck &amp; Co. Non-dazzling vehicle headlight
EP0254746A1 (en) * 1985-12-27 1988-02-03 Ichikoh Industries Limited Projector-type headlight for vehicles

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0923695B2 (en) † 1997-07-11 2013-07-17 Automotive Lighting Reutlingen GmbH Low beam headlamps and high beam headlamps for vehicles
FR2843184A1 (en) 2002-08-05 2004-02-06 Valeo Vision Projector type headlamp, for vehicle, has position of secondary focal point on secondary focal point line such that lateral distance between each secondary focal point and vertical axial plane is increasing then decreasing at least once
EP1388463A1 (en) 2002-08-05 2004-02-11 Valeo Vision Projector type headlamp capable of generating a cornering beam

Also Published As

Publication number Publication date
FR2704044A1 (en) 1994-10-21
DE69401164D1 (en) 1997-01-30
FR2704044B1 (en) 1995-07-13
DE69401164T2 (en) 1997-05-15
EP0628765B1 (en) 1996-12-18

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