Abstract:
A headlight device for a vehicle for producing light bundles with difference characteristics has at least one headlight having a plurality of headlight units, light means including a plurality of light sources with at least one light source provided for each of the headlight units, each of the light sources produces a light bundle with at least one characteristic, the headlight units being simultaneously operatable in various combinations, at least one of the headlight units being formed so that it produces a light bundle with at least two different characteristics.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a headlight device for a vehicle for producing light bundles having different characteristics.  
           [0002]    One of such headlight devices is disclosed for example in the German patent document DE 43 13 914 A1. This headlight device has several headlight units which produce correspondingly each light bundle with a predetermined characteristic. The headlight units are simultaneously operable in various combinations. For each characteristic of the light bundle, a separate headlight unit is provided, through which a light bundle with only one characteristic is produced. This requires a great manufacturing expense for the headlight device and moreover a great space consumption for accommodation of all headlight units.  
         SUMMARY OF THE INVENTION  
         [0003]    Accordingly, it is an object of present invention to provide a headlight device for vehicles of the above mentioned general type, which avoids the disadvantages of the prior art.  
           [0004]    In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated in a headlight device, in which at least one of the headlight units is formed so that light bundles with at least two different characteristics can be produced by the at least one headlight unit.  
           [0005]    The headlight device in accordance with the present invention has the advantage that the number of the headlight units which is required for producing the light bundles with different characteristics can be reduced, and as a result the manufacturing expenses and the space consumption are reduced as well.  
           [0006]    In accordance with another feature of present invention at least one headlight unit is formed so that it produces alternatingly a light bundle with a low beam characteristic or a light bundle with a high beam characteristic. Thus, only one headlight unit is required.  
           [0007]    In accordance with still a further feature of present invention, at least one headlight unit has a screen device with which it is possible to change illumination of the close region in front of the vehicle by the light bundle produced by the headlight unit, so that the illumination intensity in the close region can be weakened by the screen device. With this construction, it is possible to avoid a blinding of the opposite traffic in the event of wet streets.  
           [0008]    In accordance with still a further feature of the present invention, the headlight unit is formed so that the course of the light bundle is produced by it is changeable in a horizontal direction. Thereby the direction of the light bundle emitted by the headlight unit can be adjusted to the course of the roadway or corresponding operational conditions of the vehicle.  
           [0009]    In a still further embodiment of the present invention, at least one headlight unit is formed so that it produces a concentrated light bundle for illumination a distant region in front of the vehicle. Thereby an increased illumination of the distant region in front of the vehicle is possible.  
           [0010]    In accordance with a further embodiment of the invention, the headlight unit is formed so that the course of the light bundle produced by it can be changeable in a horizontal and/or vertical direction. This allows adaptation of the direction of the light bundle so that with low beam light the distant region under the bright-dark limit and with high beam light the distant region above the dark-bright limit is provided.  
           [0011]    Still another feature of the present invention is that at least one headlight unit is formed so that it produces a light bundle oriented at one side, with which a substantially lateral region in front of the vehicle is illuminated. This embodiment makes possible an improved illumination, in particular over a curve travel.  
           [0012]    Still another feature of present invention is that the headlight unit produces a light bundle oriented at one side, with which a lateral region is illuminated, which extends outwardly beyond the light bundle produced by the headlight unit with the low beam characteristic, or the characteristic for high beam with the illuminated region having a course which is changed in the horizontal direction. In this construction, with a small number of headlight units, it is possible to improve the illumination during driving over curves with a small curve radius and with a great curve radius.  
           [0013]    The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a simplified front view of a headlight device in accordance with the present invention;  
         [0015]    [0015]FIG. 2 is a view showing a headlight unit of the headlight of FIG. 1 in accordance with a first embodiment of the present invention;  
         [0016]    [0016]FIG. 3 is a view showing a headlight unit of the headlight of FIG. 1 in accordance with a second embodiment of present invention;  
         [0017]    [0017]FIG. 4 is a view showing the headlight unit of the headlight of FIG. 1 in accordance with a third embodiment of present invention;  
         [0018]    [0018]FIG. 5 is a view showing a headlight unit of the headlight of FIG. 1 in accordance with a fourth embodiment of the present invention;  
         [0019]    [0019]FIG. 6 is a view showing a headlight unit of the headlight of FIG. 1 in accordance with a third embodiment of the present invention;  
         [0020]    [0020]FIG. 7 is a view showing a measuring screen arranged in front of the headlight for illumination by a light bundle emitted by the headlight unit in accordance with a first and second embodiment;  
         [0021]    [0021]FIG. 8 is a view showing the measuring screen during illumination by a light bundle emitted by the headlight unit in accordance with the third embodiment of the present invention;  
         [0022]    [0022]FIG. 9 is a view showing a measuring screen during illumination by a light bundle emitted by the headlight unit in accordance with a fourth embodiment of present invention;  
         [0023]    [0023]FIG. 10 is a view showing a measuring screen during illumination by a headlight emitted by the headlight unit in accordance with a fifth embodiment of the present invention;  
         [0024]    [0024]FIG. 11 is a view showing a measuring screen during illumination by a light bundle produced by the headlight device in accordance with a further embodiment.  
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0025]    An inventive headlight device for a vehicle, in particular a motor vehicle operates for producing light bundles with different characteristics. The headlight device has at least two headlights  10  arranged in a known manner at the front end of the vehicle. FIG. 1 shows only one headlight as an example.  
         [0026]    The headlight  10  has several headlight units  12 ,  14 ,  16  which produce the light bundles with different characteristics. The characteristics of the light bundle include their course in horizontal and/or vertical direction, their bright-dark limit, their range width, and illumination intensity distribution to be produced by them. In order to maintain a low number of the headlight units  12 ,  14 ,  16  at least one of the headlight units  12 ,  14 ,  16  is formed so that by its light bundle at least two different characteristics can be produced.  
         [0027]    The headlight  10  has a headlight unit  12  which is formed so that selectively at least one light unit with a low beam characteristic, for example a low beam light, and at least one light bundle with a high beam characteristic can be produced.  
         [0028]    [0028]FIG. 7 shows a measuring screen  80  which is arranged at a distance in front of the headlight  10 , which is illuminated by the light bundle produced by the headlight  12 . The horizontal central plane of the measuring screen  8  is identified with HH and its vertical central plane is identified with VV. The horizontal central plane HH and the vertical central plane VV intersect in a point HV. The light bundle produced by the headlight  12  with characteristic for low beam illuminates a region  82  of the measuring screen  80 . The headlight unit  12  is designed for a right traffic, whereby the region  82  is limited from above by an asymmetrical bright-dark limit. The bright-dark limit at the counter traffic side, which is the left side of the measuring screen  80  has a horizontal portion  83 ,which extends substantially 1% under the horizontal central plane HH. At the traffic side itself, which is the right side of the measuring screen  80 , the bright-dark limit has a portion  84  which starts from the horizontal portion  83  and has an inclination angle of approximately 150 relative to the horizontal central plane HH. The distribution of the illumination intensity in the region  82  is represented by several lines with the same illumination intensity or so-called isolux lines  85 . In the region  82 , in the zone  86  closely under the bright-dark limit and substantially right of the vertical central plane  8 , the highest illumination intensity is provided.  
         [0029]    The light bundle produced by the headlight unit  12  with a characteristic for high beam illuminations a region  87  of the measuring screen  80 . In the region  87  furthermore several isolux lines  88  are identified. In a zone  88  around the point HV the highest illumination intensity is available. The region  87  has no pronounced bright-dark limit.  
         [0030]    [0030]FIG. 2 shows the headlight unit  12  in accordance with a first embodiment of the present invention. The headlight unit  12  is formed in accordance with a reflection principle and has a reflector  20  and a light source  21 , which can be an incandescent lamp or preferably a gas-discharge lamp. The reflector  20  with the light source  21  is arranged displaceably in a holder or a housing  22 . The light outlet opening of the housing  22  is covered by a light-permeable disk  23 , which can be formed as a smooth disk or can be provided with optical profiles for deviation and/or dispersion of the passing light. The reflector  20  can be composed of metal or synthetic plastic, and has an opening  24  provided in its apex region for the light source  21 . The light source  21  is held in a lamp carrier  25  which is supported turnably at least directly on the reflector  20  around an axis  26  extending substantially horizontally. The turning axis  26  extends near the upper edge of the lamp carrier  25 . The light source  21  extends with its glass bulb, in which during operation a light arc  27  is formed, through the opening  24  of the reflector  20 , so that the light emitted by the light arc  27  is reflected by the concavely curved reflection surface of the reflector  20 . A screen device  28  can be associated with a light source  21 . It screens a part of the light emitted by the light source  21  so that it does not fall on the reflector  20 . The screening device  28  produces the bright-dark limit of the light emitted by the headlight unit  12  with the characteristic of the low beam light.  
         [0031]    An adjusting device  29  engages the lamp carrier  25  eccentrically to the turning axis  26 . It is used for turning the lamp carrier  25  with the light source  21  about the axis  26 . The adjusting device  29  can be formed for example as an electric motor, which displaces the rod engaging on the lamp carrier  25  via a transmission. The electric motor can be formed for example as a stepper motor. The adjusting device  29  can alternatively be formed for example as an electric motor, through which the rod engaging the lamp carrier  25  can be displaced. Furthermore, alternatively it is also possible to form the adjusting device  29  as a hydraulic or pneumatic drive for displacement of the rod which engages the lamp carrier  25 .  
         [0032]    With the adjusting device  29 , the lamp carrier  25  with the light source  21  held in it, is movable between one end position for low beam light and one or several positions for high beam light. In FIG. 2 the lamp carrier  25  and the light source  21  are shown in solid lines in their end position for low beam light. The lamp carrier  25  can be located in abutment against an abutment  37 , to provide the exact arrangement of the light source  21  relative to the reflector  20 , as required for the low beam light. The lamp carrier  25  is located in its turned position relative to the reflector  20  which is the farthest opposite to the clockwise direction. The light source  21  is arranged relative to the reflector  20  so that the light emitted by the light arc  27  is reflected by the reflector  20  as a light bundle inclined downwardly. It illuminates the region  82  of the measuring screen  80  with the bright-dark limit  83 ,  84  and the shown illumination intensity distribution. The bright-dark limit  83 ,  84  can be produced by the screening device  28  and/or by a light-impermeable coating  38  of the glass bulb of the light source  21  and/or by a corresponding shape of the reflector  20 , by which the light emitted by the light source  21  is reflected so that it has the bright-dark limit  83 ,  84 .  
         [0033]    [0033]FIG. 2 shows the lamp carrier  25  and the light source  21  in broken lines in their end position for high beam light, in which the lamp carrier  28  is located in its turned position located the farthest in clockwise direction. The light source  21  in its position for the high beam light is moved opposite to its end position for the low beam light toward the apex of the reflector  10  downwardly. The lamp carrier  25  can be located in the end position for the high beam light also in abutment against a stop. In addition the screen device  28  can be spaced completely or partially from the path of beam of the light emitted by the light source  21  in its end position for the high beam light. By the change arrangement of the light source  21  reflector to the reflector  20 , the light emitted by the light source  21  can be reflected by the reflector  20  with a different characteristic than with the arrangement of the light source  21  in its end position for low beam light.  
         [0034]    The light bundle produced by the headlight unit  12  with the light source  21  in its end position for high beam light illuminates the measuring screen  80  of FIG. 7 in a region  87  identified with broken lines. In the region  87  several isolux lines  88  are shown for illustration of the distribution of the illumination intensity. In a zone  89  around the point HV, the highest illumination intensity is provided which is higher than in the zone  86  of the region  82 . The region  87 , which is illuminated by the light bundle with the characteristic of high beam light is displaced upwardly relative to the region  82  which is illuminated by the light bundle with the characteristic for low beam light. It has a pronounced bright-dark limit and the highest maximum of the illumination intensity.  
         [0035]    It can be also provided that the lamp carrier  25  with the light source  21  is turnable into one or several intermediate position between the end position of the low beam light and the end position for the high beam light.  
         [0036]    The characteristic of the light bundle produced by the headlight  12  can be changed so that starting from the end position for the low beam light toward the end position of the high beam light the characteristic changes from the characteristic for the low beam light to the characteristic to the high beam light so that the region illuminated by the light bundle on the measuring screen  80  is displaced upwardly, the bright-dark limit is less pronounced, and the maximum of the illumination intensity is higher. The turning of the lamp carrier  25  with the light source  21  can be performed for example in dependence from the speed of the vehicle. With increasing speed, the lamp carrier  25  with the light source  21  can be turned further toward the end position for the high beam light. This can be preformed for example during travel on a roadway without an opposite traffic, which can cause a blinding.  
         [0037]    The headlight unit  12  shown in FIG. 3 in accordance with a second embodiment is formed in accordance with the projection principle. The headlight unit  12  has a reflector  30  in which a light source  31  in form of an incandescent lamp or a gas discharge lamp is inserted. A lens  32  is arranged in the light outlet direction after the reflector  30  and a screen  33  is arranged between the reflector  30  and the lens  32 . After the lens  32  in the light outlet direction, a light-permeable disk  34  is arranged, which can be formed as a smooth disk or can be provided with optical profiles. The light emitted by the light source  31  is reflected as a converging light bundle.  
         [0038]    The screen  33  can be formed light-impermeable. It is movable between a position in which it extends in the beam path of the light bundle reflected by the reflector  30 , and a position in which it does not extend or extends less far into the path of beam of the light bundle reflected by the reflector  30 . The screen  32  can be turnable for example by an adjusting element  35  around an axle  36 . Alternatively, the screen  33  can be arranged stationarily, and can have a changeable light permeability. The screen  33  is switchable between a condition with a high light permeability and a condition with a low light permeability. In the operation of the headlight  12  for the low beam light the screen  33  extends in the path of beam of the light bundle reflected by the reflector  30  or located in the condition of lower light permeability. With the screen  30  a part of the light bundle reflected by the reflector  30  is screened, and the light bundle passing on the screen  33  and through the lens  32  has a bright-like limit. With the light bundle produced by the headlight unit  12  with the characteristic of the low beam light, the region  82  of the measuring screen  80  of FIG. 7 is illuminated.  
         [0039]    In the operational condition for the high beam light, the screen  33  is turned out at least partially from the path of beam of the light bundle reflected by the reflector  30  or located in its condition with high light permeability, so that a greater part of the light bundle reflected by the reflector  30  passes through the lens  32  and can exit from the headlight unit  12 . With the light bundle produced by the headlight unit  12  with the characteristic of the high beam light, the region  27  of the measuring screen  80  of FIG. 7 is illuminated. Instead, a screen  33  can be provided by two or more screens arranged near one another in the light outlet direction, and movable together or independently from one another or changeable with respect to their light permeability. The screen  33  can be movable in several stages or continuously so that starting from its position for low beam light in which it extends the farthest in the radiation direction, it arranged increasingly to its position for high beam light, and extends further far in the path of beam. Thereby the bright-dark limit produced by the screen  33  lies increasingly higher. Also, the light permeability of the screen  33  can be changeable in steps or continuously between the condition with low light permeability for producing the low beam light and the condition of high light permeability for producing the high beam light, so that the position of the bright-dark limit and/or the produced illumination intensity can be changed.  
         [0040]    With the use of gas discharge lamp as the light source  21  or  31  for the headlight unit  12 , an electrical pre-switching device  18  is needed for its operation. It serves for ignition of the gas discharge lamp  21  and after ignition guarantees a stable operation of the gas discharge lamp  21 . It can be provided that the electrical power with which the gas discharge lamp  21  is operated with the pre-switching device  18  can be changeable, so that the light current emitted by the gas discharge lamp  21  can be changed. For example, for a basic illumination, the gas discharge lamp is operated with relatively low power, for example approximately 32 watt, for a highway illumination with a higher power for example substantially 35 watt, and for a speed way illumination or for high beam with a further increased power for example substantially 38 watt.  
         [0041]    The headlight unit  12  in accordance with the first or second embodiment moreover can have a screen device  19 , by which a part of the produced light bundle can be screened at least partially, by which lower zones of the region  89  are illuminated. The lower zones of the region  82  correspond to the close region in front of the vehicle. The screening device  19  can be formed for example as a light-impermeable screen which is movable between a position in which it extends in a path of beam of the light bundle reflected by the reflector  20  or  30  or it extends in the path of beam between the light source  21 ,  31  and the reflector  20 ,  30  and a position in which it is arranged outside of the path of beam. Alternatively the screen device  19  can be arranged stationarily and can have a changeable light permeability. When the close region must be illuminated intensely, the screen device  19  is located in a condition of high light permeability, and when the close region must be illuminated weaker the screen device  19  is located in a position of lower light permeability. A weakening of the illumination of the close region is preferable for example for wet streets, for avoiding a blinding of the counter traffic. The condition of the street can be detected by a sensor device, and the weakening of the illumination of the close region can be performed automatically.  
         [0042]    [0042]FIG. 4 shows an embodiment of the headlight unit  14 , which serves for producing a concentrated light bundle. The headlight unit  14  is formed for example in accordance with the reflection principel and has a reflector  40 , and a light source  41  which can be formed as an incandescent lamp or a gas discharge lamp. The light opening of the headlight unit  14  is covered with a light-permeable disk  42 , which can be formed as a smooth disk or can be provided with optical profiles, by which the passing light can be dispersed and/or deviated. The reflector  40  is preferably turnable around at least one vertically extending axis  43  by an adjusting element  44 . The possible turning angle of the reflector  40  around the axis  43  can amount to substantially 5°-10°. Additionally, the reflector  40  is turnable about a substantially horizontally extending axis  45 . The possible turning angle of the reflector  40  around the axis  45  can amount to substantially 1°-2°.  
         [0043]    [0043]FIG. 8 shows the measuring screen  80  illuminated by a light bundle produced by the headlight unit  14 . The light bundle which is produced by the headlight unit  14  with the reflector  40  in a first position illuminates a region  90  on the measuring screen  80 , which is arranged at the right side of the vertical central plane VV of the measuring screen  80  under the portion  84  of the bright-dark limit of the region  82  and adjoining the same. The region  90  has a lower extension than the region  82 , and in particular has a lower extension in a vertical direction than the region  82 . The light bundle produced by the headlight unit  14  does not illuminate or illuminates only weakly the close region of the roadway in front of the vehicle. The light bundle produced by the headlight unit  14  amplifies in a spot-like manner the illumination of the far region on the traffic side. By turning of the reflector  40  around the vertical axis  43  the region illuminated by the light bundle produced by the headlight unit  14  is displaced in the horizontal direction, and the region  90  is displaced in a vertical direction by turning of the reflector  40  around the horizontal axis  45 . For example, in the operational condition of the headlight device for low beam light, with the light bundle produced by the headlight unit  14  the illumination of the far region above the bright-dark limit  83 ,  84  is amplified by the light bundle produced by the headlight unit  12  with the characteristic of the region  82  for low beam light.  
         [0044]    In the operational condition of the headlight device for high beam the light bundle produced by the headlight unit bundle of the headlight unit  14  lifts the illuminated region and displaces to the center of the measuring screen  80  as shown in the broken lines in FIG. 8, in order to amplify the illumination of the far region additionally to the light beam produced by the headlight unit  12  with the characteristic for high beam light. It can be provided that with the right and with the left headlight  10  of the vehicle, the front light bundles can be produced by the corresponding headlight unit  14 . For example, the light bundle produced by the headlight unit  14  of the left headlight can illuminate the region  90  under the portion  84  of the bright-dark limit, while the light bundle produced by the headlight unit  14  from the right headlight illuminates a region  91  at the left side of the measuring screen  80  under the portion  83  of the bright-dark limit. In the headlight unit  14  of the headlight of both sides of the vehicle, an adjusting possibility of the reflector  40  can be provided, or it can be provided only in the headlight unit  14  of the headlight at one side. The circuit connection of the headlight unit  14  to the headlight unit  12  can be performed for example automatically at high speed of the vehicle, during traveling over a highway or a speedway. When the circuit connection of the headlight unit  14  is performed in the operational position of the headlight device for low beam light, the light bundle produced by the headlight unit  14  must provide an illumination under the bright-dark limit. A circuit connection of the headlight unit  14  can be performed moreover automatically for wet streets or counter traffic which can be detected by sensor devices, in order to improve the visibility conditions in the high beam region. Moreover, the headlight unit  14  can be used for day travel illumination without the operation of the headlight unit  12 .  
         [0045]    The headlight unit  14  can be formed as the headlight unit  12  of the first and second embodiment and can have a movable light source  31  in correspondence with FIG. 2, or a screen which is movable or has a changeable light permeability of FIG. 3. The light bundle emitted by the headlight unit  14  can be therefore changed so that the illumination in the far region under the light-dark limit is provided, in a case of the support of the low beam light, or in far region above the bright-dark limit and in the case of the support of the high beam. The reflector  30  of the headlight unit  14  and the reflector  20  of the headlight unit  12  can be coupled with one another or can be arranged on a common carrier element, in order to guarantee the same arrangement of the bright-dark limit of the light bundles emitted by the both headlight units  12  and  14 .  
         [0046]    [0046]FIG. 5 shows an embodiment of the headlight  16 , which serves for producing a light bundle oriented at one side, for illumination of a lateral region in front of the vehicle. The headlight unit  16  is formed for example in accordance with the reflection principle and has a reflector  50  and a light source  51  which can be an incandescent lamp or a gas discharge lamp. The light outlet opening of the headlight unit  16  is covered with a lightpermeable disk  52 , which can be formed as a smooth disk or can be provided with optical profiles for dispersing and/or deflecting of the passing light. FIG. 9 shows a measuring screen  80  which is illuminated by a light bundle produced by the headlight unit  16 . The light bundle illuminates a region  92  or  93  which is arranged under the bright-dark limit  83 ,  84  of the region  82 . The region  92  is arranged at the right side of the vertical central plane VV of the measuring screen  80  and the region  93  is arranged in the left side of the vertical central plane VV. It can be provided that the right region  92  is illuminated by a light bundle produced by the headlight unit  16  of the left headlight of the vehicle, and the left region  93  is illuminated by the light beam produced by the headlight unit  16  of the right headlight of the vehicle. Alternatively, the arrangement of the regions  92 ,  93  can be opposite, so that the right region  92  is illuminated by the light beam produced by the headlight  16  on the right headlight of the vehicle, and the left region  93  is illuminated by the light beam produced by the headlight unit  16  of the left headlight of the vehicle.  
         [0047]    The regions  92 ,  93  extend in a horizontal direction for example approximately 10°-60° to the right or to the left of the vertical central plane VV. In the vertical direction the regions  92 ,  93  have substantially the same extension as the region  82  which is illuminated by the light bundle produced by the headlight unit  12  with the characteristic for low beam light. The headlight unit  16  is provided for improving the illumination in front of the vehicle during traveling over a curve. When the vehicle drives over a right curve, the headlight  16  is turned on, with which the right region  92  is illuminated, and when the vehicle travels over a left curve, the headlight unit  16  is turned on, with which the left region  93  is illuminated. The detection of the course of the roadway can be performed by one or several sensor devices, for example by a sensor device which detects a steering angle or by a video sensor device which detects the ambiance in front of the vehicle. Moreover, the course of the roadway in front of the vehicle can be determined by a navigation system which processes the information about the street network and the actual position of the vehicle. A turning on of the headlight unit  16  can be performed also by actuation of traveling direction indicator of the vehicle to achieve an improved illumination in the curved direction.  
         [0048]    The headlight unit  16  can be subdivided into two or several headlight subunits, with which the light bundles with differently strong lateral orientation are produced. For example, the headlight unit  16  can have a headlight subunit for producing a light bundle which illuminates a region of substantially 10-40° of horizontal extension near the vertical central plane VV and a central headlight subunit which produces a light bundle for illumination of a region of substantially 30-60° of a horizontal extension near the vertical central plane VV. Depending on a curve radius, the suitable headlight subunit of the headlight unit  16  can be turned on. With a greater curve radius the headlight subunit is turned on, which illuminates the region of substantially 10°-40° and with smaller curve radius the headlight subunit is turned on which illuminates the region of substantially 30°-60°, or both headlight subunits are turned on.  
         [0049]    A circuit connection of the headlight unit  16  to the headlight unit  12  can be performed for example automatically at low speed, which is for example the case in the city traffic, for improving the lateral illumination of the vehicle. For this purpose the headlight unit  16  of both headlights of the vehicle are turned on. A turning on of the headlight unit  16  can be performed further in the case of wet streets during raining, during snowfall or during fog, which can be performed automatically with the use of a suitable sensor device for detection of these conditions. Moreover, a turning on of the headlight  16  can be also performed in the case of a counter traffic, for improving the lateral illumination in front of the vehicle and thereby facilitating the orientation of the vehicle steering.  
         [0050]    [0050]FIG. 6 shows a modified embodiment of the headlight unit  16  in which the reflector  50  is turnable about a substantially vertically extending axis  53  by an adjusting element  54 . The light bundle produced by the headlight unit  16  illuminates a region  94  or  95  of the measuring screen  80  in FIG. 10, which has a horizontal extension over substantially 30-50°. By turning of the reflector  50  of the headlight unit  16 , the region  94  or  95  can be arranged with minimal turning of the reflector  50  so that it extends from substantially 10° to substantially 40-60° near the vertical central plane, while the region  94  or  95  extends with maximum turning of the reflector  50  from substantially 30° to substantially 60-80° near the vertical plane W. The turning of the reflector  50  is performed in dependence on the curve radius of the driving curve, while the reflector  50  is turned more the smaller is the curve radius. A turning on of the headlight unit  16  in accordance with this embodiment can be performed also with an actuated travel direction indicator of the vehicle.  
         [0051]    In accordance with a further embodiment of the headlight device it is provided that the headlight unit  12  is formed so that the headlight unit or at least its reflector  20  of the first embodiment or the structural group composed of the reflector  30 , the lense  32  and the screen  32  is turnable about the substantially vertically extending axis, analogously to the headlight unit  16  of FIG. 6. In addition, a headlight unit  16  is formed so that it produces a light bundle which illuminates the measuring screen  80  only at one side of the vertical central plane VV. Thereby by turning, the region  82  illuminated by the light bundle produced by the headlight unit  12  can be displaced in the horizontal direction by a predetermined distance to the left and to the right. The turning angle of the headlight unit  12  can be limited, for example to substantially 5-20°, while the turning provides an improved illumination in front of the vehicle during driving over a right or left curve with reflectively great curve radius. With the light bundle produced by the headlight unit  16 , a region is illuminated which extends in a horizontal direction of substantially 20-60° near the vertical central plane VV. The headlight unit  16  during turning over a curve with a small radius is circuit-connected to the headlight unit  12 . Turning-on of the headlight unit  16  can be also performed when the travel direction indicator in the vehicle is actuated, for reaching an improved illumination in a curved direction.  
         [0052]    The light bundle produced by the headlight unit  16  illuminates a lateral region which extends outwardly over the region illuminated by the light bundle produced by the headlight unit  12 . FIG. 11 shows a measuring screen  80 , with a region  82  which is illuminated by a light bundle produced by the headlight unit  12  in its not turned position. Broken lines illustrate the region  82  with the headlight unit  12  turned to the right and to the left. With the light bundle produced by the headlight unit  16  of the right or left headlight, the region  96  right of the vertical central plane VV is illuminated, which extends to the right outside of the region  82 , which is illuminated by the light bundle produced by it with the headlight unit  12  turned to the right. The light bundle produced by the headlight unit  16  of the other headlight illuminates the region  97  at the left of the vertical central plane VV which extends to the left outwardly beyond the region  82  illuminated by the light bundle which is produced by the headlight unit  12  turned to the left.  
         [0053]    It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.  
         [0054]    While the invention has been illustrated and described as embodied in a headlight device for vehicle for producing light bundle with different characteristics, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.  
         [0055]    Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.