FR2777976A1 - VARIABLE BEAM PROJECTOR, PARTICULARLY FOR VEHICLES, AND ASSEMBLY OF PROJECTORS OF THIS TYPE - Google Patents

Abstract

The invention provides a headlamp, in particular for a vehicle, comprising a first generally concave reflector (31), a lamp (33) fixedly mounted in the first reflector (31) and carrying a light source, and a second received reflector (32) in the concavity of the first reflector (31). The second reflector (32) is rotatable in the first reflector (31) between two positions.

Description

The present invention relates to spotlights with

  variable beam, especially for vehicles.

  It relates more particularly to projectors which are capable of generating, using a single light source, beams of the distribution route type

different light.

  Headlamps of this type have already been proposed, in particular in patent application FR 2 727 497. The main advantage of such headlamps is that the light distribution which they generate is adapted to the driving conditions of the vehicle. In general, the light distribution varies with the speed of the vehicle, in order to illuminate the regions close to the vehicle at low speed (wide beam) and to favor the illumination of the road, as far as possible,

at high speed (pointed beam).

  An object of the present invention is to provide a projector of the aforementioned type with good performance.

  optics and robust operation.

  To this end, the invention provides a headlamp, in particular for a vehicle, comprising a first generally concave reflector, having an optical axis, a lamp mounted fixed in the first reflector and carrying a light source, and a second reflector received in the concavity of the first reflector, characterized in that the second reflector is movable in rotation about the optical axis of the first

reflector between two positions.

  The invention further provides the following characteristics: - the second reflector passes from one of the two positions to the other of the two positions by rotation of an angle of 90; - The second reflector extends perpendicular to the largest dimension of the first reflector in one of the two positions and along the largest dimension of the first reflector in the other of the two positions; - The second reflector generates an asymmetrical beam along the horizontal with a mean direction different from the optical axis in one of the two positions; - The second reflector generates an asymmetrical beam along the horizontal of mean direction different from the optical axis in one of the two positions and a beam of mean direction directed upwards in the other of the two positions; - the second reflector is carried by a crown rotatably mounted in a bearing which extends around the hole of

first reflector lamp.

  The invention also provides a set of two projectors used in addition to low beams, in which the asymmetrical beam along the horizontal with a mean direction different from the optical axis

  each is headed for oncoming traffic.

  The invention further provides a set of two projectors in which the asymmetrical beams along the horizontal of each are substantially symmetrical by

  relation to the vertical plane containing the optical axis.

  The invention will now be described with reference to the accompanying drawings in which: - Figures 1 and 2 show the optical elements of a projector according to a first embodiment of the invention in front view respectively in the "beam" positions wide "and" pointed beam ", - Figure 3 is a horizontal section of the elements shown in Figure 1, - Figure 4 is a horizontal section of the elements shown in Figure 2, - Figures 5 and 6 show the optical elements d 'a projector according to a second embodiment of the invention in front view respectively in the positions "pointed beam" and "wide beam", - Figure 7 is a horizontal section of the elements shown in Figure 5, - Figure 8 is a horizontal section of the elements shown in Figure 6, - Figure 9 is a vertical section of the elements shown in Figure 5, - Figure 10 is a vertical section of the elements re presented in figure 6, - figure it illustrates an example of mechanism

  allowing the rotation of the second reflector according to the invention.

  Throughout the description, the terms vertical and

  horizontal agree with respect to the vehicle on which is

  mounted the projector according to the invention.

  FIG. 1 represents the optical elements of a projector according to the invention, namely a first reflector 11, a second reflector 12 and a light source 13. The light source 13 is here the filament of a halogen lamp type Hi . We could also foresee that the source of

  light is the arc of a discharge lamp.

  Conventionally, the optical elements are received in a box closed at the front by a transparent glass

(not shown).

  In the first embodiment (shown in

  Figures 1 to 4), the projector is of the horizontal type, i.e.

  say that its greatest direction extends horizontally.

  The first reflector 11 is also of the horizontal type. Conventionally, with this type of reflector, a

source 13 axial.

  The first reflector 11 has the shape of a paraboloid of revolution whose focal point coincides with the light source 13 and whose axis is the axis of the road (horizontal). The beam generated by the first reflector 11 is therefore a beam directed along the axis of the road (optical axis X) whose angular spreading follows directly from the extent

  spatial of the light source 13.

  The first reflector 11 may also be produced according to the teachings of patent application FR 2 664 677, in order to generate by itself a slight spreading

horizontal beam.

  The second reflector 12 is located in the concavity of the first reflector 11. The second reflector 12 has the shape of a paraboloid of revolution of axis X (optical axis) whose focal point coincides with the light source 13. The focal length of the second reflector 12 is therefore less than the focal length of the

first reflector 11.

  The second reflector 12 is composed of two parts 12a, 12b symmetrical with respect to the optical axis X. The second reflector 12 is rotatable around the optical axis X in the first reflector 11 between two positions. In the position shown in FIGS. 1 and 3, called the "wide beam" position, the second reflector 12 extends horizontally, that is to say that each part 12a, 12b of the second reflector 12 extends especially at the level of

  horizontal plane containing the light source 13.

  This position of the second reflector 12, in which it extends along the largest dimension of the first reflector 11, has two main consequences on the optical plane: - the areas of the first reflector 11 located at the horizontal ends of the latter (areas of scope which generate small images of the light source 13 and therefore a pointed beam) are masked by the second reflector; - The second reflector 12 intercepts the light flux corresponding to the aforementioned areas and reflects this light flux with a significant spreading due to the proximity of the light source 13 and the second reflector 12. This spreading is done essentially on the horizontal because of

  the horizontal position of the second reflector 12.

  These two consequences combine for the

creation of a wide beam.

  In the "pointed beam" position shown in FIGS. 2 and 4, the second reflector 12 extends vertically from the light source 13. The second reflector 12 thus extends perpendicular to the largest dimension of the

first reflector 11.

  Thus, the second reflector 12 does not (or negligibly) intercept the rays coming from the source of

  light and directed to the first reflector 11.

  The areas of the first reflector 11 located at the horizontal ends of the latter (range areas) are therefore optically active in the "pointed beam" position; the small images which they generate in the axis (small because of the relatively large distance which separates these areas of range from the light source 13) form a pointed beam. The second reflector 12 passes from the "wide beam" position to the "pointed beam" position by rotation

  around the optical axis X by an angle of 90.

  The beam generated by the second reflector 12 thus undergoes a rotation of 90; in the "pointed beam" position, the second reflector 12 produces an angularly spread beam in a vertical but narrow direction

angularly according to the horizontal.

  A second embodiment of the invention is illustrated in Figures 5 to 10. As before, only the

  optically active elements are shown in these figures.

  The first reflector 21 shown in Figures 5 and 6 is of the vertical type, that is to say that its largest dimension extends along the vertical. The second embodiment is therefore particularly suitable for the case of

  vertical type projectors or vertical projectors.

  A light source 23 which extends horizontally and perpendicular to the optical axis of the headlamp (usually called transverse source) is preferably used with a reflector of this type. It may for example be the filament of the H3 lamp conventionally mounted at the top of the

first reflector 21.

  The first reflector 21 is by itself capable of generating a pointed beam, that is to say little angularly spread. It may for example be a paraboloid of revolution whose focal point coincides with the light source 23 or a surface described in patent application FR 2 664 677 constructed to achieve a slight angular spreading. The zones situated at the vertical ends of the first reflector 21, and therefore the most distant from the light source 23, generate light beams of low angular spread (that is to say small images on a projection screen). These areas, called range areas,

  tend to form a pointed beam.

  The second reflector 22 is located in the concavity

of the first reflector 21.

  In projection on a plane perpendicular to the optical axis X, the second reflector 22 has the shape of a rectangle; we assimilate the direction of the second reflector 22 to the

  direction of the largest direction of said rectangle.

  Thus we write that the second reflector 22 is horizontal (resp. Vertical) to express that the largest dimension of the second reflector 22 in projection on a plane

  perpendicular to the optical axis is horizontal (resp.

  vertical). The second reflector 22 is rotatable in the first reflector 21 around the optical axis X, between two positions. Advantageously, the two positions are separated

angularly 900.

  In the position called "pointed beam" position and shown in Figures 5,7 and 9, the second reflector 22 is horizontal. The second reflector 22 therefore extends perpendicular to the largest dimension of the first

reflector 21.

  In the "pointed beam" position, the second reflector 22 does not mask the range areas of the first reflector 21 which thus produces a pointed beam (cf. supra). In the "wide beam" position (Figures 6, 8 and), the second reflector 22 is vertical and therefore extends

  along the largest dimension of the first reflector 21.

  In this position, the range areas of the first reflector 21 are hidden. The central areas of the first reflector 21, which generate a slightly wider angularly beam, are on the contrary uncovered and therefore

optically active.

  The light rays coming from the light source 23 towards the range areas of the first reflector 21 are intercepted by the second reflector 22 which generates a beam

spread horizontally.

  All this contributes to the formation of a broad beam. Preferably, the horizontal angular spread produced by the second reflector 22 in the "wide beam" position is asymmetrical, as clearly visible in FIG. 8. The beam generated by the second reflector 22 in this position therefore has (in projection in a horizontal plane) an average direction M different from the optical axis X. Reference may in particular be made to patent application FR 2 732 446 for producing a reflector having such properties. The mean direction M 'of the beam generated by the second reflector 22 in the "pointed" beam position will therefore not be parallel to the optical axis X. Advantageously, this mean direction M' is directed upwards. This avoids creating a light spot on the pavement at the front

  of the vehicle, bothersome for the driver.

  It is clear that, starting from the "wide beam" position, it suffices to choose the direction of rotation (AH in the figures) which allows the second reflector 22 to generate

a rising medium beam.

  The projectors which have just been described (asymmetrical beam) can be used differently

According to the case.

  In the first case, the headlamps are used in addition to dipped beam asymmetrical headlamps, as for example in the application for

Patent FR 2,750,375.

  In this case, advantageously a projector (s) according to the invention will be used, the second reflector 22 of which generates, in the "wide beam" position, a beam whose mean direction M is directed towards the side of oncoming traffic. This completes the beam of the spotlights of

crossing in a natural way.

  Another solution consists in using only two projectors in accordance with the invention in each of which the second reflector 22 generates in the "wide beam" position a

asymmetrical beam.

  In this case, the second reflector 22 of each projector will be constructed so that the two beams generated by them in the "wide beam" position are substantially symmetrical with respect to the vertical plane containing the optical axis. As before, the direction of rotation of the second reflector 22 is chosen in each headlamp which makes it possible to obtain a beam directed upwards in position

"pointed beam".

  This gives a beam of good photometry, pleasant to roll, in the "pointed beam" position as

in the "wide beam" position.

  It will be noted that, advantageously with a transverse source, the thickness (vertical spreading) of the beam is minimized in pointed beam and in wide beam one obtains a much larger horizontal spreading because the dimension of the source to be taken into account is the length of the filament which is

much larger than its diameter.

  FIG. 11 illustrates a solution for implementing the

  mechanism which rotates the second reflector 32.

  The first reflector 31 illustrated in this figure receives a lamp 33 at the level of a lamp holder 41. The lamp 33

carries a light source.

  Near the lamp holder 41, and preferably integral with it, extends a bearing 40 bearing in rotation about the optical axis X a ring 35. The bearing 40 extends around the recess 43 of the first reflector 31 which receives the lamp 33 and which is generally called the lamp hole. Arms 34 extend from the crown 35 and carry at their end opposite the crown 35 the second

reflector 32.

  A motor with rotary output 36 is fixed to the rear of the first reflector 31. The motor 36 rotates the crown 35 via a drive system

37.

  More specifically, the motor 36 rotates a toothed wheel 38 which in turn drives a transmission element 39. The rotation of the transmission element 39, which passes through the first reflector 31, causes the rotation of a wheel tooth 42 which meshes on the

  toothed outer circumference of the crown 35.

  The invention is not limited to the above examples, which are only embodiments

favorite of it.

O10

Claims (8)

RESELL I CATIONS   1. Projector, in particular for a vehicle, comprising a first reflector (11, 21, 31) generally concave, having an optical axis (X), a lamp (33) fixedly mounted in the first reflector (11, 21, 31) and carrying a light source (13, 23), and a second reflector (12, 22, 32) received in the concavity of the first reflector (11, 21, 31), characterized in that the second reflector (12, 22, 32) is mobile in rotation around the axis (X) of the first   reflector (11, 21, 31) between two positions.   2. Projector according to claim 1, characterized in that the second reflector (12, 22, 32) passes from one of the two positions to the other of the two positions by rotation of a angle of 90.   3. Projector according to claim 2, characterized in that the second reflector (12, 22, 32) extends perpendicular to the largest dimension of the first reflector (11, 21, 31) in one of the two positions and according to the largest dimension of the first reflector (11, 21, 31) in the other of the two positions.   4. Projector according to one of claims 1 to 3,   characterized in that the second reflector (12, 22, 32) generates an asymmetrical beam along the horizontal with a mean direction (M) different from the optical axis (X) in one of the two positions.   5. Projector according to one of claims 1 to 3,   characterized in that the second reflector (12, 22, 32) generates an asymmetrical beam along the horizontal of mean direction (M) different from the optical axis (X) in one of the two positions and a beam of mean direction (M ') directed   up in the other of the two positions.   6. Projector according to one of claims 1 to 5,   characterized in that the second reflector (32) is carried by a crown (35) rotatably mounted in a bearing (40) which extends around the lamp hole (43) of the first reflector (31).   7. Set of two projectors each produced according to claim 4 or 5 and used in addition to dipped projectors, characterized in that the asymmetrical beam along the horizontal with a mean direction (M) different from the optical axis (X) of everyone is headed from the side oncoming traffic.   8. Set of two projectors each produced according to claim 4 or 5, characterized in that the asymmetrical beams along the horizontal of each are substantially symmetrical with respect to the vertical plane containing the axis optical (X).