EP0380396A1 - Motor vehicle headlamp comprising one light source and producing two different beams - Google Patents

Abstract

Motor vehicle headlamp, of the type comprising one light source (100), a reflector (200) comprising two zones capable of producing respectively two different light beams, a cover lens and occultation means which are situated in the vicinity of the source and capable of being displaced in order selectively to occult the light rays emitted from the source towards at least one of two zones. According to the invention, the two zones of the reflector are arranged side by side and each extend over the entire height of the reflector, each zone of the reflector consists of a part of a reflective surface independently producing the associated beam, and the occultation means comprise at least one screen (410) which, in the occulting position, is situated laterally with respect to the source. …<IMAGE>…

Description

The present invention relates generally to motor vehicle headlamps, and more particularly relates to a headlamp capable of emitting two light beams of different types using a single light source, by mechanically acting on the geometry of source / reflector cooperation.

More specifically, the invention relates to a projector of the type comprising a single light source, a reflector comprising two zones capable of respectively generating two different light beams, a closing lens and occultation means located in the vicinity of the source and capable of be moved to selectively obscure the light rays from the source towards at least one of the two zones.

A projector of this type is already known in the prior art.

More specifically, French Patent No. 1,296,036 describes (page 2, right column) as a particular embodiment a projector in which the filament is fixed relative to the reflector, and the reflector comprises a parabolic upper part whose focal point is offset behind the filament, to form a passing beam, and a lower part also parabolic, but focused in the vicinity of the filament, to form in combination with the upper part a driving beam. The two parts of the reflector are separated from each other in the horizontal plane passing through the optical axis, while an occlusion screen is capable of selectively intercepting the rays coming from the source in the direction of the part. lower to change the route / crossing.

A main disadvantage of this type of projector is that, because the cut-off of the passing beam is directly created by the edge of the screen or screens, and because of the inevitable games in the mechanical design of such a mobile blackout screen, the position of the cut-off is defined with an imprecision which is not compatible with the photometric requirements imposed by the various regulations.

This phenomenon is further accentuated in projectors of this type responding to current design trends, that is to say having a very reduced height and a large width. This means that the cutoff will be defined, at least as far as the concentration images are concerned, by regions of the reflector very far from the source and from the screen, and therefore with an undesirable amplification of the positioning error of the blackout screen.

Yet another drawback of known spotlights lies in the difficulty in favoring the intensity of one beam to the detriment of the other. More precisely, taking into account the aforementioned low height requirement, the search for a gain in light for one of the beams leads to giving the reflector a greater width. But in this case, the other beam also benefits from such a gain, so that the ratio between the quantities of light specific to the two beams remains substantially the same.

Also known from French Patent No. 690 678 is a projector which comprises a parabolic mirror of which a matt or frosted lateral zone is permanently exposed to the radiation of the source and the other zone of which can be obscured by a concealing element. lateral. Such a known spotlight is therefore not capable of generating two different beams, since only the concealable zone is capable of forming a beam. This document cannot therefore be of any interest in solving the problem to which the present invention relates.

The present invention aims to overcome these drawbacks of the prior art and to propose a projector in which the photometry of the beams, and in particular the definition and the position of the cut-off of a passing beam or of an anti-fog beam, either independent of possible play or inaccuracies in the position of a screening screen intervening to form the beam considered.

Another object of the present invention is to provide a headlamp of the type specified in the introduction which can without disadvantage have an extremely reduced height, in accordance with current design requirements.

Yet another object of the present invention is to provide a projector in which, without having to modify its general configuration, it is easy to modify the surface area of the reflective zone assigned to each type of beam.

Finally, the invention aims to propose such a projector, in which the two beams formed can be either complementary or independent.

To this end, according to the present invention, the two zones of the reflector are arranged side by side and each extend over the entire height of the reflector, each zone of the reflector consists of a part of a reflecting surface. generating by itself the associated beam, and the occultation means comprise at least one screen which, in the occultation position, is situated laterally with respect to the source.

Preferred aspects of the projector of the invention are as follows:
- At least one of the two zones of the reflector is constituted by a surface capable of generating by itself a beam located below a cut of generally horizontal orientation, and can be constituted by a surface capable of forming images of the light source whose highest points are located in the vicinity of the cut. The cut can be horizontal or a cut delimited by a horizontal half-plane and by a half-plane inclined above the horizontal. In this case, the other zone of the reflector is preferably constituted by a surface capable of generating a concentrated beam in the vicinity of the optical axis.
- the occultation means can comprise either a single screen for selectively obscuring the rays coming from the source in the direction of said other zone, or even two screens for selectively obscuring the rays coming from the source towards the two zones of the reflector, respectively . In this case, the screen capable of obscuring the rays emanating from the source in the direction of the first zone of the reflector may be crossed by at least one small orifice to allow a determined quantity of light to pass in the direction of said first zone.
advantageously, the screen or each screening screen comprises a plate articulated around a horizontal axis secured to a cover of direct light associated with the source, this plate being able to be brought into a screening position by a driving source such as an electric motor associated with transmission means comprising for example gears and a link.
- Finally, the source is preferably an arc lamp.

An essential advantage of the headlamp according to the invention lies in that the cut-off of the beam (s) is no longer defined by the mobile blackout screen, but by the reflector itself. As a result, this cutoff is defined with an excellent position and sharpness regardless of play, vibration, etc., which may affect the position or the stability of the screen.

• la figure 1 est une vue de face simplifiée d'un projecteur conforme à l'invention,
• la figure 2 est une vue en coupe horizontale du projecteur de la figure 1,
• la figure 3 est une vue en coupe verticale axiale du projecteur des figures 1 et 2,
• les figures 4a et 4b sont des vues de face schématiques du projecteur des figures 1 à 3, illustrant deux états possibles de celui-ci,
• les figures 5a à 5d sont des vues de face schématiques illustrant quatre états possibles d'un projecteur selon une variante de réalisation de l'invention, et
• les figures 6a et 6b sont des vues de côté d'une réalisation concrète d'un dispositif d'occultation conforme à l'invention, présenté dans deux positions différentes.

Other aspects, objects and advantages of the present invention will appear better on reading the following detailed description of a preferred embodiment thereof, given by way of example and made with reference to the accompanying drawings, in which :

• FIG. 1 is a simplified front view of a headlamp according to the invention,
• FIG. 2 is a view in horizontal section of the projector of FIG. 1,
• FIG. 3 is a view in axial vertical section of the headlight of FIGS. 1 and 2,
• FIGS. 4a and 4b are schematic front views of the projector of FIGS. 1 to 3, illustrating two possible states of the latter,
• FIGS. 5a to 5d are schematic front views illustrating four possible states of a projector according to an alternative embodiment of the invention, and
• Figures 6a and 6b are side views of a concrete embodiment of a concealment device according to the invention, presented in two different positions.

Referring firstly to Figures 1 to 3 and 4a, 4b, a projector according to the invention comprises a lamp 100, a reflector 200 and a closing front lens 300. In this example, the lamp is a discharge lamp , capable of producing between two electrodes an elongated electric arc disposed essentially axially in the vicinity of the optical axis 0x, in a well known manner. In 102 and 104 are indicated respectively the base and the sealed bulb of the lamp. Its power supply terminals are designated by 108. Due to the importance of the light flux emitted by this type of lamp, a direct light cover 106 is also provided to avoid the glare of the drivers or pedestrians located in front of the vehicle. The cover 106 here has the form a cylinder of revolution closed at its front end and whose open rear end has a complex contour such that the rays directed towards optically inoperative parts of the reflector (cheeks, etc.) are intercepted by the cover.

Of course, it is also possible to use a filament lamp, such as a tungsten filament, or any other lamp comprising a single light source.

The reflector 200 is here a reflector of low height and large width, truncated by two upper and lower cheeks 240, 250, essentially horizontal. In accordance with an essential aspect of the invention, the surface of the reflector 200 is divided into two distinct reflecting zones 210 and 220 capable of emitting two light beams of different types respectively, and this separation is carried out in the present example according to the plan vertical axial x0z of the projector. A separation along two half-planes passing through the optical axis Ox, but of substantial inclination relative to the horizontal, as indicated by the dashed lines P and P ′, is also conceivable. It is thus possible to easily modify the respective areas of the reflecting zones 210, 220, and consequently the intensities of the two beams formed.

For example, the left zone (in front view) 210 of the reflector can be constituted by a part of a reflective surface capable of generating by itself, that is to say without the intervention of a cover. blackout or the like, the V-cut specific to the European standard passing beam. In practice, it may be half of an area among those described in French patents and patent applications No. 2,536,502, 2,599,121 and 2,609,148 in the name of the Applicant, the respective contents are incorporated herein by reference, and to which reference will be made for further details.

In the present example, the right-hand zone 220 of the reflector is a part of a surface capable of generating a beam essentially complementary to the passing beam. It may, for example, be a portion of a paraboloid relative to the focal point from which the arc is off-center, or even a half of the surface as described in French patent application No. 2,600,024, the content is also incorporated by reference and to which reference will be made for further details.

The projector also comprises, as shown diagrammatically in FIGS. 4a and 4b (and not illustrated in FIGS. 1 to 3 for the sake of clarity, a screening screen 420 which here has the shape of a half-cylinder of revolution d the horizontal axis essentially coincides with the optical axis, which is articulated by an edge on an axis 440 parallel to the optical axis and situated below the lamp, this axis being for example mounted on the direct light cover 106.

Drive means (not illustrated), for example with an electric motor or an electromagnet, can be controlled from the passenger compartment of the vehicle to move the screen 420 between a first position or concealed position (FIG. 4a), in which it is placed against the cover 106 to intercept the radiation from the arc of the lamp in the direction of the zone 220 of the reflector, and a second position or erasing position (FIG. 4b), in which it is released of the cover 106, the area 220 now being exposed to radiation. It is observed that, in this example, the zone 210 is always exposed to radiation.

It is clear that, in the situation in FIG. 4a, only the zone 210 is active, so that the beam formed is a European passing beam. In this respect, it can be noted that the various surfaces mentioned more high have the property of creating by themselves the whole of the beam even when only half of the surface is used. And given the very large amount of light generated by an arc source, the intensity of the beam obtained is more than acceptable.

In the situation of FIG. 4b, the whole of the reflector participates in the creation of the beam, so that the latter is constituted by the superposition of the driving beam generated by the area 210 and the complementary beam generated by the area 220, and thus constitutes a driving beam.

With reference now to FIGS. 5a to 5d, there are diagrammatically illustrated four possibilities of using a headlamp comprising a first reflecting zone 210 such as a surface forming by itself a passing beam and a second reflecting zone 220 in the form parabola focused in the vicinity of the arc of the lamp 100. Two screening screens 410, 420, for example articulated and mounted on the same axis 440 located below the lamp 100, are respectively associated with the areas 210 and 220 , to selectively expose them to light from the arc or, on the contrary, hide them. This projector is further characterized in that the blackout screen 410 assigned to the area 210 of the reflector comprises one or more small orifices, as indicated in 412, to allow a determined amount of the light emitted by the direction of the reflector. the arc.

In FIG. 5a, the two screens 410, 420 are in the occultation position, as illustrated, and only a small amount of the light from the arc is allowed to exit towards the zone 210, which normally reflects it forward. . In this way a so-called lantern or city lamp function is created, delivering a small amount of light in front of the vehicle for the vehicle signaling more than road lighting.

In FIG. 5b, the concealment screen 410 is open. This situation is equivalent to that of FIG. 4a, and the headlamp emits a passing beam.

Illustrated in FIG. 5c is the case where the blackout screen 410 is closed, while the blackout screen 420 is open. Only the zone 220 of the reflector participates in the shape of the beam, so that the beam generated is an ordinary driving beam, concentrated on the optical axis.

Finally, FIG. 5d illustrates a last possibility offered by this reflector: by simultaneously opening the two screens 410, 420, the driving beam and the passing beam are superimposed, in this case obtaining an extremely powerful beam, offering visual comfort to both in the distance and closer to the vehicle.

Thus, without any electrical switching of the lamp, but by appropriately controlling the means for moving the screening screens, this projector offers four light functions, all of excellent quality.

Figures 6a and 6b illustrate a practical embodiment of the concealment means used in the context of the present invention. Illustrated in these figures is a screening screen 410 intended to selectively mask the radiation from the electric arc the left part (in front view) 210 of the reflector.

On a common support (not shown), for example integral with the reflector or the projector housing and molded therewith, is mounted a reversible electric motor 401 whose output shaft 401a carries a first gear 402. The latter meshes with a train reducer constituted by the gears 403, 404 and 405. The final gear 405 carries an eccentric pin 406 on which a first end of a link 407 is articulated.

The direct light cover 106, here of essentially square cross section, carries on a vertical extension 106a an axis 409 on which the screening screen 410 is articulated by means of a tab 410a. At the free end of the tab 410a, that is to say opposite to the part providing the concealment with respect to the axis 409, there is provided an axis 408 on which the other end of the link 407 is articulated.

It is understood that a rotation of the motor 401 causes, by means of the transmission constituted by the gears and the link, the passage of the screen 410 from the non-occultation or erasure position, illustrated in the figure. 6a, in the occultation position illustrated in FIG. 6b, and vice versa. To precisely ensure the positioning of said screen in each of its two possible positions, it is possible for example to provide limit switches at an appropriate location of the transmission, or even a servo position control, these two solutions being well known from one skilled in the art.

It is observed that the blackout screen 410 has a contour such that, in the blackout position, it seals the entire space between the rear edge of the cover 106 and the base 102 of the lamp, to thus effectively preventing any ray from reaching the reflecting area 210 of the reflector.

Thus, the present invention, by a side-by-side arrangement of the reflective zones and, in combination, by the use of reflective surfaces capable of forming beams, in particular cut, without the screening screen intervening in the formation of the on the one hand, allows to realize back projectors with two functions and single source using an arc source, known for its high brightness but hitherto unused in practice because the switching between two arcs takes place in an incompatible duration with the regulations, and on the other hand to realize projectors with two functions and single source of extremely reduced height, which meets well the current design requirements.

The present invention, by allowing the use of a single arc source, also makes it possible to achieve substantial savings compared to projector systems comprising not only two expensive arc lamps but also two equally expensive power supplies for these lamps.

Of course, the present invention is not limited to the embodiments described above and shown in the drawings. In particular, although the use of a discharge lamp is particularly advantageous for obvious efficiency reasons, it is clear that the invention remains advantageous with conventional tungsten filament sources.

Furthermore, any combination of beams other than that which has been indicated above can be envisaged. For example, one can provide a zone forming the European standard passing beam as described above, the other zone possibly being a parabola possibly off-center or a surface capable of forming a beam complementary to a passing beam. In the above headlamps, it is also possible to replace the zone forming the passing beam by a zone forming by itself a fog beam, and responding for example to the surface as described in French patent application No. 2,536 503 on behalf of the Applicant, the content of which is incorporated into the present description by reference.

Another possibility consists in using for the concealable zone 220 a portion of paraboloid focused on the source and giving a so-called "spot" beam, extremely concentrated, and for the non-concealable zone 210 a surface such as that described in the application for Patent No. 2,609,148, generating by itself a very wide driving beam.

Finally, the electromechanical occultation means as described can be the subject of numerous variants. For example, the drive can be performed using an electromagnet instead of the electric motor. It is also possible to use non-electromechanical occultation means, for example an electro-optical screen capable of assuming an opaque state and a transparent state, depending on the value of an electric voltage which is applied across its terminals.

Generally, a person skilled in the art will know how to conceal means having a switching speed fast enough to comply with the regulations, in particular with regard to the crossing crossing en route and vice versa and "the lighthouse call ".

Claims (12)

1. Motor vehicle headlamp, of the type comprising a single light source (100), a reflector (200) comprising two zones (210, 220) capable of respectively generating two different light beams, a closing glass (300) and occultation means (410, 420) located in the vicinity of the source and which can be moved to selectively obscure the light rays emanating from the source towards at least one of the two zones, characterized in that the two zones ( 210, 220) of the reflector are arranged side by side and each extend over the entire height of the reflector, in that each zone of the reflector is formed by a part of a reflecting surface generating by itself the associated beam and in that the occultation means comprise at least one screen (410, 420) which, in the occultation position, is situated laterally with respect to the source. 2. Projector according to claim 1, characterized in that at least one of the two areas (210) of the reflector is constituted by a surface capable of generating by itself a beam located below a cut d general horizontal orientation. 3. Projector according to claim 2, characterized in that said zone (210) is constituted by a surface capable of forming images of the light source whose highest points are located in the vicinity of the cut. 4. Projector according to claim 3, characterized in that the cut is a horizontal cut. 5. Projector according to claim 3, characterized in that the cut is a standardized cut delimited by a horizontal half-plane and by a half-plane inclined above the horizontal. 6. Projector according to one of claims 2 to 5, characterized in that the other zone (220) of the reflector is constituted by a surface capable of generating a concentrated beam in the vicinity of the optical axis. 7. Projector according to claim 6, characterized in that the occultation means comprise a single screen (420) for selectively occulting the rays coming from the source in the direction of said other zone (220). 8. Projector according to claim 6, characterized in that the occultation means comprise two screens (410, 420) for selectively occulting the rays coming from the source in the direction of the two zones (210, 220) of the reflector, respectively. 9. Projector according to claim 8, characterized in that the screen (410) capable of obscuring the rays from the source in the direction of the first zone (210) of the reflector is crossed by at least one small orifice (412) to let a determined quantity of light pass in the direction of said first zone. 10. Projector according to one of the preceding claims, characterized in that the screen or each screening screen comprises a plate (410, 420) articulated around a horizontal axis (409) secured to a cover of direct light (106) associated with the source, this plate being able to be brought into a concealed position by a driving source (401) associated with transmission means (402-408). 11. Projector according to claim 10, characterized in that the driving source is constituted by an electric motor (401) and in that the transmission means comprise gears and a link. 12. Projector according to one of the preceding claims, characterized in that the source is an arc lamp (100).

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