FR2754500A1 - PROJECTOR INSTALLATION FOR VEHICLE EMITTING A VARIABLE LIGHT BEAM - Google Patents

Abstract

Installation comprising a headlight unit (10), a detection installation (12) detecting humidity in the environment of the vehicle, in particular of the roadway at the front of the vehicle as well as a control installation (14). This controls the operation of the projector unit (10). When the environment is dry, the unit (10) emits a beam of usual low beams illuminating both the near range and the remote area at the front of the vehicle. When the environment is humid, the installation (14) modifies the beam emitted by the unit (10) so that it no longer illuminates the range close to the roadway at the front of the vehicle in its middle zone or at least it lights it less strongly than when the road is dry.

Description

Technical States: The present invention relates to an installation of

  headlamp for a vehicle, emitting a variable beam of light comprising at least one headlamp unit; a detection facility which detects the weather conditions

  in the environment of the vehicle and, a

  command which exploits the signals of the detection installation and operates according to this detection, at least

  a projector unit according to a predetermined characteristic

  mined to emit a light beam, this light beam

  having an upper illumination limit.

  Such a projector installation is known

  according to document DE 42 15 940 Al. This installation of pro-

  connector comprises at least one projector unit and one insert

  detection system which determines the packaging

  atmospheric conditions around the vehicle. At least one pro-

  jector can generate the low beam and emit a

  light beam having an upper limit of illumination.

  The detection installation is connected to an

  control tallation which exploits the signals that it

  provides and depending on these signals it controls the varia-

  tion of the light beam emitted by at least one pro-

  jector. The variation of the light beam emitted by at least one projector unit is thus controlled by

  the control system depending on the atmospheric conditions

  spherical around the vehicle. The atmospheric conditions concerned are for example the presence of fog which is

  detected by the detection installation carried out as an

  optoelectronic detection system. When the instal-

  detection lation detects the arrival of fog, the control installation modifies the light beam emitted by at least one spotlight unit with respect to the light beam emitted without fog to improve the conditions

visibility for the driver.

  It was found that by high humidity in

  the vehicle environment, especially when the road surface

  before the vehicle is wet, there is a stronger glare from the drivers of the vehicles coming opposite coming

  that the wet pavement has a coefficient of

  higher deflection than that of a dry and reflective pavement

  chit the light forward. In particular, the light of the

  vehicle that illuminates the road surface at the front of the vehicle

  hicule dazzles a driver coming opposite. This difficulty also exists in the case of known projector installations according to the type defined above. Advantages of the invention:

  The invention relates to a projection installation

  tor corresponding to the type defined above, characterized in that the detection installation detects the humidity in the environment of the vehicle, in particular of the roadway upstream of the vehicle and the control installation operates at least one headlamp unit for a humid environment of the vehicle so that the light beam emitted by this unit does not illuminate the area near the roadway at the front

  of the vehicle, in its median zone considered in the direction

  tion or at least illuminates it less intensely

  only when the vehicle is in a dry environment.

  The projector installation according to the invention

  has the advantage that in case of high humidity around the vehicle

  especially when the roadway in front of the vehicle is

  wet, as the control system prohibits lighting

  rage on the beach near the roadway, we avoid dazzling-

  the conductors coming opposite by the light which would be reflected by the wet pavement or at least we reduce

this glare.

  According to other advantageous features of the invention: the detection installation comprises an installation for detecting humidity on the exterior surface of a window

  provided in the front area of the vehicle.

  * the detector installation includes a humidity sensor provided on the vehicle preferably near the

pavement.

  According to another advantageous characteristic of the invention: ò the detection installation also detects visibility conditions in the environment of the vehicle and for low visibility;

  * the control system reduces the range of the beam

  miners emitted by at least one projector unit in relation to the range it would have for high visibility;

  * at least one projector unit has at least one

  positive cut-off which allows the part of the light beam to be emitted by the headlamp unit towards the area

  median of the beach near the roadway at the front of the

  hicule when the environment is dry and that cuts this

  part of the light beam when the environment is humid

  mide. According to these characteristics, one can modify the

  light beam from a projector unit.

  According to another advantageous characteristic of the invention: * at least one projector unit comprises at least two projector sub-units; * the light beam of a headlamp subunit which essentially illuminates the beach near the roadway at the front of the vehicle at its median zone, and the light beam of another headlamp subunit illuminates with other areas at the front of the vehicle; * the operation of the projector sub-unit emitting the light beam illuminating the beach is prohibited by

  the control system when the environment of the vehicle

cule is wet.

  By simply cutting or plugging in the spotlight unit illuminating the nearby range, this

lighting or we allow it.

  According to other advantageous features of the invention:

  * the projector unit has at least one other sub-

  headlamp unit emitting a light beam which illuminates the remote area at the front of the vehicle and whose operation is prohibited by the installation for controlling cases of low visibility and / or high humidity or which modifies the direction of the emitted light beam by this

  projector unit for illuminating a remote area,

diane at the front of the vehicle.

  Drawings: The present invention will be described below from

  in more detail using several examples of

  reading shown schematically in the accompanying drawings in which: - Figure 1 is a simplified view of the front of a vehicle fitted with a headlamp installation, - Figure 2 shows a measurement screen placed in front of the headlamp installation and which is lit by this installation by light emitted by the vehicle in a dry environment,

  - Figure 3 shows the measurement screen lit by the installation

  Projector lation by the light emitted when the envi-

the vehicle is damp,

  - Figure 4 shows the measurement screen lit by the installation

  headlamp connection when the vehicle environment is humid and visibility is reduced,

  - Figure 5 shows a projector unit of the installation

  tion of a projector according to a first exemplary embodiment,

  - Figure 6 shows a projector unit of an installation

  tion of a projector according to a second exemplary embodiment,

  - Figure 7 shows a projector unit of the installation

  projector according to a third exemplary embodiment

tion,

  - Figure 8 shows a projector unit of the installation

  tion of a projector corresponding to a fourth embodiment,

  - Figure 9 shows an example of an installation

  detection lation belonging to the projection installation

  Figure 10 shows an embodiment of an installation of

  projector installation control.

  Description of the exemplary embodiments:

  A vehicle, in particular a motor vehicle

  presented in simplified form in FIG. 1 comprises a

  projector installation with at least one projection unit

  light 10 at the front of the vehicle to emit a beam of variable light. Preferably, there is at least one spotlight unit 10, the two lateral zones of the end

  front of the vehicle, installed like a conventional headlamp.

  The projector installation also includes an installation

  detection 12 which detects humidity in the environment

  vehicle ment; this installation is connected to a control installation 14 which exploits the signals of

  the detection installation 12 and controls the light beam

  emitted by at least one projector unit 10 as a function of this detection. The characteristic of the beam of light emitted is modified with regard to the direction, the inclination, that is to say the dispersion in the horizontal direction, the

  range and position of the illuminating light which delimits

try the beam.

  In the case of a dry environment of the vehicle, at least one headlamp unit 10 emits a beam of dipped beam which illuminates an area 52 of a measurement screen 50 shown in FIG. 2 and which is placed at a certain distance in front of the projector unit 10, perpendicular to its optical axis. The projector unit 10 is provided for

  equip a vehicle for a right-hand traffic country.

  The measurement screen 50 represents the roadway located in front of the vehicle and the lateral edges of which bear the reference 54

  on the measurement screen 50 and the axis line, reference 56.

  The horizontal median plane of the measurement screen 50 bears the reference HH and its vertical median plane the reference VV. The horizontal median plane HH and the vertical median plane WVV intersect at point HV. Zone 52 is bounded upwards by a lighting limit which, on the traffic side

  coming in the opposite direction, that is to say in the present case cor-

  corresponding to the traffic on the right, on the left side of the measurement screen 50, has a horizontal segment 58; this

  segment is slightly below the median horizontal plane

  zontal HH. On the vehicle traffic side, that is

  say in the present case for right-hand traffic, on the right side of the measurement screen 50, the illumination limit has a segment 59, rising towards the right edge of the measurement screen 50 starting from the horizontal segment 58. Alternatively, the illumination limit may also have a horizontal segment 58 on the side of oncoming traffic as well as another horizontal segment 61, on the side of traffic of the vehicle, which is however more

  higher in the vertical direction than segment 58; this seg-

  ment 61 is represented by a broken line in FIG. 2.

  When the projector unit 10 equips a vehicle

  traffic circulating in a country with left-hand traffic, the seg-

  58, 59 or 58, 61 of the lighting limit must be exchanged with respect to the vertical median plane VV. In the

  illuminated area 52, several lines 60 of the same shape have been drawn

  light intensity also called Isolux lines. Inten-

  the highest lighting locations in the illuminated area 52 are found substantially to the right of the vertical median plane VV and slightly below the rising segment 59 of the illumination limit; the lighting intensity decreases regularly towards the lateral edges and towards the lower edge of the area 52. The area 52 arrives in the vertical direction, in an area adjacent to the vertical median plane WVV, on both sides,

  far down, so that the beach near 55 of the shoe

  located directly in front of the vehicle is illuminated

  dream. Overall, in the event of a dry environment of the vehicle, the light emitted by the headlamp unit 10 ensures both

  adequate lighting of the area far from the roadway

  directly below the lighting limit 58, 59 and a

  Sufficient lighting of the beach near the front of the vehicle.

  Thus, the detection installation 12 detects humidity in the environment of the vehicle, the control installation 14 modifies the light beam emitted by at least one projector unit 10 so that this beam illuminates the measurement screen 50 in the area with reference 62 to

  Figure 3. Area 62 is bounded upwards by the line

  light mites 58, 59 or 58, 61 such as zone 52 and the

  position of this lighting limit is unchanged from

  port to that of FIG. 2. The extension of zone 62 in

  vertical direction, in an area adjacent to both sides

  However, the vertical median plane VV is reduced compared to

  port to the extension of zone 52 of FIG. 2, so that in the vertical direction, zone 62 does not descend as

  far than zone 52 and the beach near 55 of the roadway, from-

  Before the vehicle, viewed in the horizontal direction, is lit in the middle area with less lighting intensity. The part of the light beam which illuminates the near range 55 can be cut so as not to leave the

projector 10 to stop being used.

  As a variant, this part of the light beam

  can be changed in its direction to have a tilt

  its lower and thus illuminate a range closer to the light-dark area 58, 59 or 58, 61. This improves the lighting of the area far from the roadway directly below the chiaroscuro limit 58, 59; 58, 61. In the area of the edges 54 of the roadway, the intensity of the lighting in the area 62, is not reduced compared to the area 52 of FIG. 2. Like the near range 55 of the roadway is only lit with a low light intensity, this area of the roadway will reflect little light avoiding

  thus any glare from a conductor coming opposite.

  In addition, in the event of high humidity in the environment of the vehicle and low visibility, for example as a result of heavy rain, snowfall or fog, the light beam emitted by at least one headlight unit 10 can be even more modified by the control installation 14. The light beam emitted by the projector unit 10 can be modified to have a lower range compared to the light beam which illuminates the area 62 according to FIG. 3. This makes it possible to reduce the back glare of the driver of the vehicle by water droplets or snowflakes suspended in the air, and which is produced by the light beam emitted by his own projector unit; by the small distance of the illuminated areas below the lighting limit thus lowered, we get better lighting of the view area

  average in a part between approximately 30 m and 45 m.

  It is advantageous in very bad weather conditions to give up lighting the remote area located at a distance of the order of 45 m to 65 m and more in favor of better lighting in the area of average remoteness, because the traffic speeds in such conditions are not very high and thus the lighting of the average remote area is more important than that of the remote area. The light beam emitted by the projector unit illuminates the measurement screen 50 of FIG. 4 in an area

  72 shifted even further down in the vertical direction

  wedge with respect to zone 62 of FIG. 3.

  The lighting limit 78, 79 which delimits the top of this zone is lower than the lighting limit 58,

  59 of zones 52 and 62 in the vertical direction. To avoid

  ter too intense lighting of the near range in front of the vehicle in an area of the measurement screen 50 adjacent to the vertical median plane VV, the extension of the area 72 in the vertical direction has been further reduced relative to that of the zone 62 of FIG. 3 so that zone 72 does not descend

  lower in the vertical direction than zone 62. The par-

  tie of light beam which illuminates the measurement screen 50 above

  above the lighting limit 78, 79 or below the lower limit of the area 72 can again be cut

  so as not to leave the projector unit 10 or see its di-

  rection modified to have a greater inclination and

also light up area 72.

  You can change the light beam emitted by at

  minus one projector unit between the steps described above

  on it but other intermediate steps are also

  possible, so that the light beam varies progressively

  The lighting characteristic of the area 52 of the screen 50 according to FIG. 2 up to the lighting characteristic of the area 62 of FIG. 3. Likewise, several intermediate steps can be provided for passing the

  light beam from the lighting characteristic of zone 62 according to FIG. 3 to that of zone 72 according to FIG.

  gure 4, so that the chiaroscuro limit 78, 79 gradually decreases and the corresponding vertical extension

  of zone 72 thus gradually decreases.

  Figure 5 shows a first example of realization

  tion of the projector unit 10. This unit 10 is constructed according to the principle of reflection; it includes a reflector 20 equipped with a light source 21. Seen in the direction 22 of the light output, downstream of the reflector 20,

  one can provide a transparent window 23. The light source

  neuse 22 can be an incandescent lamp or a gas discharge lamp. In the direction of exit of the light 22, downstream of the window 23, another transparent window 19 can be provided which constitutes the window covering the headlight unit 10. The reflector 20 can be defined in its shape to reflect the light emitted by the source

  light 21 and form a light beam having the characteristic

  necessary for lighting the measurement screen. As a variant or in addition, the disc 23 may comprise at least per zone, the optical elements which deflect the light passing through them and thus the light beam leaving the projector

  has the necessary characteristic.

  To modify the characteristic of the beam

  miners leaving the projector unit 10 to illuminate the different zones 52, 62 or 72 of the measurement screen 50 according to FIGS. 2-4, mobility can be envisaged, that is to say a translation or a tilting of the light source 21 controlled by the control installation 14 by

  through an actuator 24 acting on the light source

  miner 21. Alternatively or additionally, the

  characteristics of the light beam leaving the projector 10

  by a mobility, that is to say a sliding or a rocking-

  ment of parts of reflector 20 or of the whole of reflector

  20; this can also be done by the control installation 14, by an actuator 25 acting on the reflector 10.

  Finally, to modify the characteristic of the

  light beam leaving the headlamp unit 10, in addition to or as a variant of the embodiments described above, at least part of the window 23 comprising optical elements is

  introduced into the path of the beams of reflected light

  shit by the reflector 20 or be extracted from this path;

  for this, the control installation 14 acts on an action-

  neur 26 acting on this part of the glass 23 to move this part of the glass 23. In all cases, the parts of the light beam leaving the headlamp unit, in a case of operation in a dry environment

  of the vehicle, are changed in their direction by the shift

  cementing of the light source 21 and / or of the parts of the reflector

  tor 20 and / or parts of the glass 23 .; thus, these light beams no longer illuminate the near range 55 of the roadway according to FIGS. 2-4 and / or the area remote from the roadway below the horizontal median plane HH of the measurement screen 50 according to FIG. 4 or only light it up

  only with low light intensity.

  Figure 6 shows a second example of realization

  tion of the projector unit 10, the basic construction of which corresponds to the first embodiment. However, as a variant of the first embodiment, no mobility

  of the light source 21 is neither provided nor parts of the

  flector 20 or parts of the glass 23; on the contrary, a screen device 27, 28 is provided which cuts the corresponding parts of the light beam leaving the projector unit 10 and which would illuminate the near range

  or the area away from the roadway at the front of the vehicle.

  It is also possible to provide a screen device 27 which

  cuts the part of the light beam illuminating the pro-

  che and another screen device 28 which cuts the part

  tie of the light beam illuminating the remote area.

  The breaking devices 27, 28 can be

  displaced to come in the path of the beams of the

  reflected or reflected by the reflector 20; for this, an actuator 29 is provided, activated by the control installation 14. As a variant, the cut-off devices 27, 28 can also be fixed and have a

  variable transparency; the control system 14 com-

  requires the highest transparency when the environment of the vehicle is dry so that all the light reflected by the reflector 20 can exit from the headlight unit 10; to cut off certain parts of the light beam,

  the control system 14 switches the switching devices

  pure 27, 28 so that they have a low transparency. The variation of the transparency in the light of the breaking devices 27, 28 can for example be done with a voltage

  applied by the control system 14.

  Figure 7 shows a third example of reali-

  projector unit 10 working according to the principle

  projection type; it includes a reflector 30 with a light source 31, a lens 33 provided in the direction of light output 32 downstream of the reflector 30 as well as a diaphragm 35 provided between the lens 33 and the reflector 30 below its optical axis 34 The reflector 30 reflects the light emitted by the light source 31, part of which passes the screen 35 and passes through the lens 33 to be deflected.

  so that the light beam exiting the projection unit

  tor 10 has the required characteristic.

  In addition, in the path of the rays of light

  passing through the lens 33, it is possible to place a transparent glass

  annuity 36 provided with optical elements making it possible to deflect the light which passes through. Diaphragm 35 creates the limit

  illumination of the light beam exiting the pro-

  junction 10. The diaphragm 35 can be movable in the direction

  vertical tion to change the position of the limit

  illumination of the light beam emitted to pass from the posi-

  tion of the lighting limit 58, 59 according to FIGS. 2 and 3 at the position of the lighting limit 78, 79 according to FIG. 4. For this, an actuator 37 controls the diaphragm 35. This actuator is activated by the control installation 14. En

  alternatively, the diaphragm 35 may be fixed and have a trans-

  variable speed controlled by the control system 14.

  In addition to the diaphragm 35, it is also possible to provide a provision

  cut-off point 38 above the optical axis 34 which selectively cuts the part of the light beam illuminating the near range. The breaking device 38 can be mobile and it is placed by an actuator 39 controlled by the control installation 14; it can also be fixed and have a

  variable transparency controlled by the installation of

request 14.

  Figure 8 shows a third example of reali-

  projector unit 10 formed of at least two

  protector sub-units 40, 41. The projecting sub-units

  teurs 40, 41 each have a reflector 42 and a

  light source 43 and can operate according to the principle

  cipe of reflection or that of projection. At least

  a projector sub-unit 40 emits during its operation

  ment a light beam which illuminates the measurement screen 50 of FIG. 2 in the area 52 without however the near range

  55. At least one other projector subunit 41 is emitting during

  during its operation, a light beam which mainly illuminates only the near range 55 according to FIG. 2. The operation of the projector sub-unit 41 is controlled by the control installation 14 so that in the event of high humidity in the environment of the vehicle, lighting of the near range 55 is avoided simply by switching off

the projector sub-unit 41.

  The projector unit 10 may further include

  another projector sub-unit 44 which does not light in operation

  practically that the remote area lying

  directly below the lighting limit 58, 59. In this case, the projector sub-unit 40 can be modified to emit in operation a light beam which illuminates the area 52 but not the near range 55 and, where appropriate, no longer the remote area illuminated by the light beam emitted by the

  projector sub-unit 44. The operation of the sub-

  spotlight unit 44 is also controlled by the control installation 14 so that when the visibility is reduced, this sub-unit can be cut or even be modified in its direction for the light beam emitted, and allow switching of the lighting from zone 62 of the measurement screen 50 according to FIG. 3 to the lighting of zone 72 of the measurement screen 50 according to FIG. 4. The unit

  projector 10 may also include other sub-

  spotlight units which illuminate different times

  areas of the measurement screen 50 and can operate independently

* especially from each other so that the light beam emitted by the projector unit 10 can be modified within a very wide range. The variation of the light beam can also be done according to other conditions

  environment and / or traffic conditions

  calculates such as traffic density or traffic

  circulation size. It is also possible to provide a headlamp unit which mainly illuminates the adjacent zone situated below the lighting limit, to which corresponds the zone of average distance to the front of the vehicle by this headlamp unit; this projector unit can be

  added by the control system 14 in case of high humidity

  midity and / or poor visibility in front of the vehicle The detection installation 12 may for example include a sensor

  humidity 89 provided at the front of the vehicle as close as possible to the road to detect the humidity of the road. The humidity sensor can be mounted in particular near the wheels of the vehicle, for example in the body of a wheel to be exposed to

  the moisture circulated by the wheels during driving

  vehicle culation. As a variant, in addition to the humidity sensor, the detection installation 12 may also include an installation 90 for detecting humidity at the

  exterior surface of a window. The glass can be for example-

  ple the windshield of the vehicle or a window covering a headlamp unit or another installation

  vehicle lighting. At this time we can use notably -

  an installation controlled by the actuation of an in-

  cleaning facility or wiper installation

of the corresponding window.

  The basic structure of such an installation is shown in FIG. 9. The installation 90 is provided on the inside of the window 91; it comprises a light source 92, for example a photodiode. The light

  emitted by the light source 92 is detected by a slow

  tille 93 which deflects it towards a photoconductive body 94 for

  that it enters the window 91. The window 91 conducts the

  by total reflection and this is then again

  decoupled from the glass 91 using another photocon-

conductor 95 at a remote location.

  The photoconductive body 95 deflects the light and by a lens 96 the light again leaves the photoconductive body 95 to reach a photosensitive element 97, for example a photodiode. Photodiode 97 is connected to

  the control installation 14 which processes the signals. When-

  that the outer surface of the glass 91 is dry, a certain

  ten fraction of the light emitted by the photodiode 92 is again decoupled from the window 91, so that the signal

  emitted by photodiode 97 has a certain intensity.

  On the other hand, if the exterior surface of the window 91 has

  a certain humidity, for example in the form of a drop-

  of water 98, part of the light is decoupled from the glass 91, so that a smaller fraction of the light

  sort of window 91 to arrive on photodiode 97 emits-

  so much a weaker signal. This is detected by

the control system 14.

  Figure 10 is a block diagram of a rea-

  Possible reading of the detection installation 12 comprises for example as indicated above, a humidity sensor 89 as well as an installation 90 for detecting the humidity on the external surface of the window 91, these two installations being connected to the control installation 14. The control installation 14 can for example comprise a logic circuit which compares the signals of the detection installation 12 at different thresholds Si, S2 and according to the result of the

  comparison, using 102 power electronics, it

  order at least one spotlight unit 10 to put it in

  a defined operating mode. A first threshold If corresponds

  thus lays at an average humidity on the outer surface of

  window 91 or wet pavement. A second threshold S2 cor-

  responds to significant humidity on the exterior surface of the glass 91. When the signal SF from the humidity sensor 89 and the signal SR from the detection installation are both below the threshold S 1, this makes it possible to conclude that the roadway upstream of the vehicle and the exterior surface of the window 91 are dry. In this case, the control installation 14 operates the projector unit 10 in its position

  LV1 operating; in this position, the beam

  emitted miners illuminates the measurement screen 50 in the area 52 se-

  in FIG. 2. When the signal SF from the humidity sensor 89 exceeds the corresponding threshold Si or the signal SR from the detection installation 90 exceeds the corresponding threshold Si, this means that either the roadway at the front of the vehicle ,

  either the outer surface of the window 91 are wet.

  In these cases, the control installation 14 operates the projector unit 10 in its operating position LV2 in which the emitted light beam illuminates the measurement screen 90 in the area 62 according to FIG. 3. When the signal SR of detection facility 90 also exceeds

  its second threshold S2, we conclude that the living conditions

  sibility are bad. In this case, the installation of

  command 14 operates the projector unit 10 in its

  LV3 operating position in which the beam

  emitted by this unit illuminates the measurement screen 50 se-

in Figure 4 in area 72.

  As a variant, the detection installation 12 may comprise one or more other sensors 100 which detect the visibility conditions at the front of the vehicle and are connected to the control installation 14, and for these at

  minus a threshold is stored in the installation of

  command 14. When the signals from the sensors 100 exceed their threshold, the control installation 14 operates the projector unit in an operating position LV3 in which the emitted light beam illuminates the measurement screen 50 in the area 72 according to Figure 4. It is clear that between

  thresholds Si and S2, other corresponding thresholds can be provided for

  laying on a finer subdivision according to which the

  switching of the projector unit 10 will also take place

  be the finer subdivided operating positions

  between which the light beam emitted by the unit

  projector 10 changes each time only slightly.

  Switching of the headlight unit 10 from the operating position LV3 back to the operating position LV2 or LV1 can take place if the signals from the detection installation 12 again pass below the corresponding thresholds S2 or S1. It is also possible to provide other threshold values for switching the headlamp unit 10 from the operating position LV3 to LV2 or LV1, which allows a certain hysteresis avoiding alternations

  fast between the different operating positions LV3, LV2, LV1. It is also possible not to store fixed thresholds in the control installation 14 and 10 to choose them variably according to the technique known as fuzzy logic.

Claims (7)

R E V E N D I C A T IONS   1) Headlamp installation for a vehicle, emitting a variable beam of light comprising, - at least one headlamp unit (10), a detection installation (12) which detects the weather conditions in the environment of the vehicle and, - a control installation (14) which uses the signals from the detection installation (12) and operates in   depending on this detection, at least one projection unit   tor (10) according to a predetermined characteristic for emitting a light beam, this light beam having an upper illumination limit, characterized in that - the detection installation (12) detects humidity in the environment of the vehicle, in particular the roadway upstream of the vehicle and, - the control installation (14) operates at least one headlamp unit (10) for a humid environment of the vehicle so that the light beam emitted by   this unit does not light the beach near (55) the shoe   located at the front of the vehicle, in its median zone considered in the horizontal direction or at least illuminates it   less intensely than when the vehicle is in an envi- dryly.   2) Installation according to claim 1, characterized in that the detection installation (12) comprises an installation (90) for detecting humidity on the external surface of a   window (91) provided in the front area of the vehicle.   3) Installation according to any one of claims 1   or 2, characterized in that the detector installation (12) comprises a sensor   humidity (89) provided on the vehicle preferably near mite from the roadway.   4) Installation according to any one of claims 1 to 3, characterized in that   the detection installation (12) further detects the conditions   visibility in the environment of the vehicle and for low visibility, the control installation (14) reduces the range of the light beam emitted by at least one projector unit (10) compared to the range it would have for great visibility.    ) Installation according to any one of the claims   above, characterized in that at least one spotlight unit (10) comprises at least one cut-off device (27, 28) which allows the part of the light beam to be emitted by the spotlight unit (10) to the median area of the beach close (55) to the roadway at the front of the vehicle when the environment is dry, and which   cuts this part of the light beam when the environment is wet.   6) Installation according to any one of claims 1   to 4, characterized in that - at least one spotlight unit (10) comprises a light source (21), a reflector (20) and if necessary a transparent window (23) placed in the path of the light rays of the light reflected by the reflector (20),   - the light source (21) and / or at least the parts of the lamp   flector (20) and / or at least the parts of the glass (23) are movable, and   - for a dry environment of the vehicle, part of the   light beam coming out of the spotlight unit (10)   The area near (55) the roadway at the front of the vehicle, at its median zone, is modified in   its direction to illuminate other areas in front of the vehicle hicle.   7) Installation according to any one of claims 1 to 4, characterized in that   at least one projector unit (10) has an installation   diaphragm (35) which creates the limit of illumination of the light beam leaving the projector unit (10) and, the diaphragm installation (35) can be modified in its position and / or in its transparency to modify the scope of the light beam.   8) Installation according to any one of claims 1   to 4, characterized in that - at least one projector unit (10) comprises at least two projector sub-units (40, 41), - the light beam of a projector sub-unit (41) which illuminates essentially the beach close (55) to the   roadway at the front of the vehicle at its metropolitan area   diane, and the light beam of another subunit of   headlamp (40) illuminates other areas at the front of the vehicle cule,   - the operation of the projector sub-unit (41) emits   both the light beam illuminating the area (55) being prohibited by the control installation (14) when   the vehicle environment is humid.   ) Installation according to claim 8, characterized in that   the projector unit (10) has at least one further sub   headlamp unit (44) emitting a light beam which illuminates the remote area at the front of the vehicle and whose operation is prohibited by the control installation (14) in cases of low visibility and / or high humidity or which modifies the direction of the light beam emitted by this   headlamp unit (44) for lighting a remote area, median at the front of the vehicle.    ) Installation according to any one of claims 8   or 9, characterized in that the headlamp unit (10) comprises at least one headlamp sub-unit emitting a light beam illuminating a distant central area at the front of the vehicle and in that in case of high humidity and / or poor visibility at the front of the   vehicle, it is connected by the installation of mande (14).