Light-emitting device for a motor vehicle headlamp and headlamp equipped with said device

A light-emitting device for a motor vehicle headlamp, said device comprising a housing, a light source disposed on said housing and an optical device directing one or more light beams emitted by said source, said housing comprising a projecting element for allowing a fixed position of said optical element with respect to said housing. This device is noteworthy in that said projecting element comprises at least one hollow rib formed inside an enclosure defined by said housing and said optical device comprises, opposite the housing, a slot that nests at least partially with said hollow rib of said housing.The invention also relates to a headlamp, in particular for a motor vehicle, comprising said emitting device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to French Application No. 1261779 filed Dec. 7, 2012.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light-emitting device for a motor vehicle headlamp and also to a headlamp equipped with the device. Although provided more particularly for use in additional headlamps such as foglamps, the invention may also be used in high-beam lamps, low-beam lamps or any other type of vehicle headlamp that is used to light the roadway.

Additional headlamps are understood to be headlamps intended to be added to a vehicle after it has been manufactured, in order to personalize it, in contrast to what are known as built-in headlamps that are present on the vehicle when it leaves the production line. The former are very often optional whereas the second are very often mandatory on account of the regulations in force.

2. Description of the Related Art

In this field, emitting devices that comprise a housing accommodating a light source and an optical device directing a light beam emitted by the source are known.

Good positioning of the source with respect to the optical device is necessary in order that the beam emitted by the optical device is guided correctly, in particular when the source comprises light-emitting diodes.

Various positioning solutions have already been proposed.

In the case of the additional headlamps, it is known in particular to position the headlamp with respect to its surroundings while it is being fixed to the vehicle. However, this solution does not always allow satisfactory positioning precision.

In the case of the built-in headlamps, it is known to position the optical device while giving it one or more degrees of freedom, allowing the height of the beam emitted to be adjusted. However, such solutions are relatively complex.

SUMMARY OF THE INVENTION

The invention has the aim of remedying the above-mentioned drawbacks and to this end proposes a light-emitting device for a motor vehicle headlamp, the light-emitting device comprising a housing, a light source disposed on the housing and an optical device directing one or more light beams emitted by the light source.

According to the invention, the housing comprises a projecting element for allowing a fixed position of said optical device with respect to the housing. A “fixed” position is understood to mean a position in which the optical device is immobilized in all spatial directions.

By having the light source supported by the housing and by positioning the optical device with respect to the housing, better indexing of the optical device with respect to the light source is obtained without the use of additional components. Definitive fixing of the optical device to the housing may be obtained by any suitable, possibly complementary, means.

According to various features of the invention which may be taken together or separately:the projecting element comprises at least one hollow rib formed inside an enclosure defined by the housing,the hollow rib of the housing is rectilinear and/or comprises a number of arms,the optical device comprises, opposite the housing, a slot that nests at least partially with the hollow rib of the housing,the slot forms a hollow rib on an opposite face of the optical device from the housing,the light source emits one or more light beams centered on an axis which is transverse to an optical axis of the light-emitting device,the light source comprises one or more light-emitting diodes,the light-emitting diode or diodes are fixed to a printed circuit board,the diode or diodes are disposed in the region of the hollow rib of the housing, notably in the region of side walls of the hollow rib of the housing,the hollow rib of the housing supports the LEDs, in particular via the printed circuit board,the hollow rib of the optical device comprises one or more openings for allowing the light emitted by the diode or diodes to pass through,the optical device is a reflector,the reflector reflects all or part of the beam emitted by said light source so as to shape the beam emitted by the light-emitting device,the reflector is positioned on the hollow rib of the housing such that the diode or diodes is/are located at one or more foci of the reflector,the reflector comprises a number of reflection cavities, in particular each cavity cooperating with a separate light source; according to an optional embodiment, the hollow rib of the reflector separates these various cavities,in a preferable, but nonlimiting manner, the hollow rib of the reflector, the cavities and the light sources are arranged such that the light rays emitted by a given one of the light sources only reaches the reflector cavity that is associated therewith,the reflector and the hollow rib or ribs of the reflector separating these cavities are made in one piece from the same material,the housing defines an enclosure for the light source,the light source is in thermal contact with the housing and said housing is designed to allow thermal dissipation of the heat released by the light source,the hollow rib of the housing is designed to increase the heat exchange surface area,the hollow rib of the housing is oriented toward the inside and/or the outside of the housing,the hollow rib of the housing comprises two flanks connected by a bottom,the hollow rib of the housing, as seen from outside the housing, forms a groove,the hollow rib of the housing is made from the same material as the housing,the hollow rib of the housing is furnished with heat dissipation fins,the fins are located in said groove,the fins are located outside the enclosure defined by the housing,the fins are located within the volume of the housing, that is to say that they do not protrude beyond the outer surface of the housing,the hollow rib or ribs has/have a longitudinal axis of extension,the fins are transverse to said direction of extension of the hollow rib of the housing,the fins extend from the bottom of the hollow rib of the housing to edges of the flanks thereof, opposite the bottom, and/or from one of the flanks to the other,the fins are at least provided in the vicinity of a part of the hollow rib of the housing carrying the light source,the fins are distributed regularly along the hollow rib of the housing,the housing comprises flanges for fixing to a support,the flanges are located on either side of the hollow rib of the housing, at one of the ends thereof.

According to this last feature, it is possible to adjust the height of the beam emitted without, however, making use of adjusting mechanisms that modify the orientation of the optical device with respect to the housing.

The invention also relates to a motor vehicle headlamp comprising the emitting device as described above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As illustrated inFIGS. 1 to 3, the invention firstly relates to a light-emitting device1for a motor vehicle headlamp2.

The light-emitting device1comprises a housing6and a light source4disposed on the housing6which defines in this case an enclosure8for the light source4.

The device1also comprises an optical device directing one or more light beams emitted by the light source4. the optical device is designed in particular to concentrate the light beam or beams emitted by the light source4. In this way, the beam emitted by the light-emitting device1, which could in particular be located inside an emission cone centered on an optical axis12of the light-emitting device1, is shaped.

The optical device is, for example, a reflector10for reflecting the beam or beams emitted by the light source4. In an alternative or combined manner, it may of course comprise any other optical element, such as lenses, for directing while intensifying the beam or beams emitted by the light source4.

The light source4comprises at least one light-emitting diode14. The diode or diodes14is/are placed, for example, on a support16such as, in particular, an insulated metal substrate, for supplying the diodes14with electricity. The supports15may also incorporate electronic components (not shown) which are involved in the control of the diodes14.

According to the invention, the housing6comprises a projecting element for allowing a fixed position of the optical element with respect to the housing6. This provides a particularly simple solution that encourages correct placement of the optical device with respect to the light source4.

The projecting element comprises at least one hollow rib18formed inside the enclosure8defined by the housing6. The hollow rib18of the housing6is advantageously designed to immobilize the optical reflector in all spatial directions.

According to a preferred embodiment, the diode or diodes14is/are disposed, in particular fixed, in the region of the hollow rib18of the housing6, notably in the region of flanks20of the hollow rib18, in particular on either side of the hollow rib18.

The source4in this case emits one or more light beams centered on an axis which is transverse, in particular orthogonal, to the optical axis12of the light-emitting device1according to the invention and the optical device rectifies the beam or beams emitted in order to direct them along the optical axis12.

The flanks20of the hollow rib18of the housing6are connected in this case by a bottom22. The hollow rib18of the housing6has a U-shaped section, the flanks20being approximately parallel.

The hollow rib18of the housing6is advantageously made from the same material as the housing6. In other words, the housing6and the hollow rib18of the housing6form one and the same single component.

The housing6comprises, for example, a bottom24having an axisymmetrical form, interrupted by the hollow rib18of the housing6. The shape of the bottom24of the housing6corresponds, for example, to a spherical cap and/or ellipsoid of revolution.

The optical device and in particular the reflector10could comprise, opposite the housing6, a slot that nests at least partially with the hollow rib18of the housing6. Such nesting facilitates the desired positioning effect, in particular by centering. The slot forms in this case a hollow rib32on an opposite face of the reflector10from the housing6.

The hollow rib32of the reflector10may cover the hollow rib18of the housing6and comprise one or more openings34for allowing the light emitted by the diode or diodes14to pass through. The openings34for the passage of the beam emitted by the light source4are located in this case opposite the diodes14.

The reflector10may have one or more foci and the hollow ribs18,32are designed such that the light source4, namely the diodes14in this case, are located substantially at the foci(for example, F1and F2inFIG. 2). The reflector10may in particular be designed such that the light rays emitted by the diodes14are reflected parallel to one another, in the direction of the optical axis12.

In the embodiments inFIGS. 1 to 4, the hollow rib18of the housing6is located on either side of a plane of symmetry passing through the optical axis12of the device, orthogonal to the section plane inFIG. 2.

The flanks20of the hollow rib18of the housing6thus have outer edges23in the form of an arc of a circle and/or ellipse. The flanks20are connected here to the bottom22of the hollow rib18of the housing in a rectilinear manner. The latter is domed slightly toward the inside of the enclosure8.

In a corresponding manner, the reflector10may be symmetrical with respect to the abovementioned plane of symmetry. The hollow rib32thereof comprises, for example, two flanks36, in which the openings34are respectively formed. The flanks36of the hollow rib32of the reflector10are connected, in particular, by a bottom38, which is slightly convex in this case. The reflector10comprises in this case two bottom parts28,30in the form of portions of a paraboloid of revolution that are connected by the hollow rib32of the reflector10.

In these embodiments, the hollow ribs18,32are, for example, rectilinear. In use, the hollow ribs18,32are intended to be oriented vertically. As a variant, they may also be intended to be used horizontally.

As illustrated inFIG. 5, as a variant, they may also comprise a plurality of arms56a,56b,56c. It is in this case in the form of a star, in particular having three arms. The bottom of the reflector10is thus divided into three zones55a,55b,55cthat are designed to each reflect the rays emitted by the corresponding diodes in the direction of the optical axis12.

Such an embodiment makes it possible to produce by itself locking in all spatial directions.

In the embodiments inFIGS. 1 to 4, the cooperation of the hollow ribs18,32makes it possible to obtain locking in at least two spatial directions.

In the embodiment inFIGS. 1 to 3, locking in the third direction, namely the vertical direction in the figures, may be obtained by a clamping effect.

In the embodiment inFIG. 4, as illustrated by the various arrows, it may be obtained by respective abutment surfaces62located notably on said hollow rib18of the housing6.

This being the case, with reference toFIG. 2, the reflector10has in this case a peripheral edge40projecting with respect to a peripheral edge42of the housing6. The bottom38of the hollow rib32of the reflector10projects with respect to the peripheral edge40of the reflector10. The bottom22of the hollow rib18of the housing6is set back with respect to the peripheral edge42of the housing6. The light-emitting device1according to the invention comprises a cavity44between the bottom22of the hollow rib18of the housing6and the hollow rib32of the reflector10.

As can be seen more particularly inFIGS. 4 and 5, the reflector10may comprise, for example, a peripheral skirt60along its peripheral edge40, placed opposite the peripheral edge42of the housing6.

It may be noted that the reflector10advantageously comprises a number of reflection cavities, namely in this case two in the embodiment inFIGS. 1 to 4and three in the embodiment inFIG. 5, the reflection cavities being separated by the hollow rib32of the reflector10. Each cavity cooperates respectively with one of the light-emitting diodes14.

The hollow rib32of the reflector10, the cavities and the light-emitting diodes14may be arranged such that the light rays emitted by a given one of the light-emitting diodes14only reaches the cavity of the reflector10which is respectively associated therewith.

The reflector10and the hollow rib or ribs32of the reflector10separating these cavities are, for example, made in one piece from the same material.

According to another aspect of the invention, the light source4is in thermal contact with the housing6, the latter being designed to allow thermal dissipation of the heat released by the light source4.

To this end, the housing6may be produced, for example, from a metal material such as aluminum or an aluminum alloy, or any other metal or metal alloy that has good thermal conductivity. As explained in the following text, it may also have one or more forms that favor the presence of surfaces for heat exchange with the ambient air.

This provides a solution in which the function of cooling the light source4is carried out by the housing6itself, thereby making it possible to reduce the number of components and to give the headlamp equipped in this way an advantageous appearance.

In this regard, it will be understood that the hollow rib18of the housing6and, in particular, the flanks20thereof allow a first increase in the heat exchange surface area provided by the housing6.

As can be seen more readily inFIG. 3, the hollow rib18of the housing6may be furnished with heat dissipation fins26located in this case outside the enclosure8defined by the housing6.

Advantageously, the extension given to the fins26limits them in the volume provided by the bottom24of the housing6: the fins26do not pass beyond the outer surface of the housing6. This level of integration helps to give the device according to the invention a favorable appearance.

The fins26are in this case transverse to the direction of extension of the hollow rib18of the housing6or of the arms thereof. They extend, for example, from the bottom22of the hollow rib18of the housing6to the edges23thereof and/or from one flank20of the hollow rib18of the housing6to the other.

As a variant, they may be parallel to the axis of extension or have any other orientation that is favorable to circulation of air by natural convection.

The fins26are at least provided in the vicinity of a part of said hollow rib18of the housing6carrying the light source4, in particular in the region of the supports16. The fins26are in this case distributed regularly along the hollow rib18of the housing6. However, any other distribution is possible.

In order to further improve the appearance of the housing6, the latter will advantageously have a smooth outer surface, that is to say one without forms or other fins that are intended to increase the heat exchange surface area, outside the hollow rib or ribs of the housing6.

The invention also relates to the headlamp2comprising the emitting device1.

With reference toFIG. 1, the headlamp2may also comprise a closing outer lens50and optionally a style part, or mask, located between the closing outer lens50and the reflector10, along the optical axis12of the emitting device.

The outer lens50and/or the housing6may each comprise a lip52,54for bearing against one another. They are secured together, for example, by a double-sided adhesive (not shown), placed in this case between the lips52,54.

The headlamp2also comprises, for example, a trim ring58, in two annular parts62,62′ that are axially joined together. This ring58makes it possible in particular to conceal the connection between the outer lens50and the housing6.

The housing6may comprise flanges64for fixing to a support, in particular a support mounted on a motor vehicle (not shown). The flanges64are located in this case on either side of the hollow rib18of the housing6, at one of the longitudinal ends thereof. They are designed to allow, in use, an adjustment of the inclination of the beam emitted by the headlamp2with respect to the horizontal.

The headlamp2may in particular be used as a foglamp, although this application should not be considered limiting in anyway.

While the system, apparatus, process and method herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise system, apparatus, process and method, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.