Abstract:
The present invention comprises a bending lamp apparatus and method of use. A first filament is energized as a vehicle begins to turn so as to provide illumination in the direction of the turn. As the turn becomes more severe, a second filament is energized such that an additional area is illuminated in the direction of the turn.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates generally to automotive lighting systems and, more specifically, to automotive bending lamps.  
           [0002]    In response to changing driving conditions, it can become desirable to adjust the beam pattern of a headlamp assembly relative to the vehicle. For example, when a vehicle is being driven around a corner, it may be desirable for the beam pattern of that vehicle&#39;s forward lighting system to be adjusted, axially and/or laterally, such that the emitted light better illuminates the area in the direction the vehicle is turning. The vehicle lighting industry refers to lighting used to illuminate the path of a vehicle while the vehicle is turning as “bending light.”. Automotive headlamps wherein the forward light beam of the headlamp is physically re-aimed to provide bending light are generally known in the industry as adaptive front lighting systems (“AFS”). AFS lighting systems can be very expensive, because of the control systems needed to physically re-aim the light beam.  
           [0003]    In certain applications, rather than moving the forward light beam pattern, the vehicle lighting industry has developed static supplemental lighting fixtures which are aimed so as to illuminate the general direction in which a vehicle is being turned. Static supplemental lighting fixtures which are used to provide bending light are controlled on and off by means generally known in the art. These systems, while less expensive than AFS systems, have certain limitations. For example, some turns are more severe than other turns, yet the static supplemental lighting fixtures cannot be further adjusted to better illuminate the path of the vehicle.  
           [0004]    Therefore, it is desirable to provide a bending lamp that allows for significant angular displacement of the light beam of a headlamp assembly without excessive light beam distortion and without the need to move the entire headlamp assembly. It is further desired that the system be of inexpensive and dependable construction, while providing for increased scope of illumination as the severity of the turn is increased. It is further desired that the headlamp assembly be easily configured to fit within space confines of a variety of vehicle designs.  
           [0005]    Brief Summary of the Invention  
           [0006]    In accordance with the present invention, a bending lamp system comprises two filaments within a static bending light fixture. According to one embodiment of the invention, a dual filament static bending light fixture may be located within a standard headlamp assembly for ease of design and construction. The dual filament static bending light fixture includes a reflector. The first filament provides illumination of the vehicle&#39;s path for less severe turns. The second filament, which may be, but need not be, of the same wattage, is activated for more severe turns. The filaments are offset such that the second filament creates an additional area of illumination. Moreover, the reflector prescription and/or lens prescription may be designed so as to focus the light from the two filaments into the desired beam pattern. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1. is a diagrammatic view of a dual filament bulb within a reflector according to the present invention with only one filament energized.  
         [0008]    [0008]FIG. 2 is a diagrammatic view of the dual filament bulb within a reflector of FIG. 1 with both filaments energized.  
         [0009]    [0009]FIG. 3 is a diagrammatic view of a vehicle with only forward lighting energized.  
         [0010]    [0010]FIG. 4 is a diagrammatic view of the vehicle of FIG. 3 during a slight turn in which a first bending light filament is energized in accordance with the present invention.  
         [0011]    [0011]FIG. 5 is a diagrammatic view of the vehicle of FIG. 4 during a severe turn in which a first and a second bending light filament is energized in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0012]    Referring to FIG. 1, one embodiment of the present invention is described. FIG. 1 is a diagrammatic view of a dual filament bulb within a reflector according to the present invention. Fixture  10  comprises reflector  12 , a first filament  14  with a first optical axis  15 , and a second filament  16  with a second optical axis  17 . In FIG. 1, filament  14  is energized, and light rays  18  and  20  show exemplary light rays formed by first filament  14  and reflected off reflector  12 .  
         [0013]    Referring now to FIG. 2, the dual filament bulb of FIG. 1 is shown with both filaments energized. Filament  16  is energized, and light rays  22  and  24  show exemplary light rays formed by second filament  16  and reflected off reflector  12 .  
         [0014]    Operation of fixture  10  is described with reference to FIGS.  3 - 5 . FIG. 3 is a diagrammatic view of a vehicle with only forward lighting energized. Headlamp assemblies  36  and  38  in this embodiment include forward lamp fixtures as well as fixture  10 . Wheels  30  of vehicle  32  are shown in a generally forward configuration. Thus, when moving, vehicle  32  would move in the direction generally indicated by arrow  34 . Accordingly, filament  14  and filament  16  are not energized, and only areas  40  and  42  are illuminated.  
         [0015]    Referring now to FIG. 4, wheels  30  of vehicle  32  are shown turned away from the generally forward configuration of FIG. 3. Thus, when moving, vehicle  32  would move in the direction generally indicated by arrow  44 . In accordance with the present invention, the turn condition is sensed as having exceeded a threshold, and filament  14  is energized. Thus, illumination is provided by filament  14  to area  46 . Those of skill in the art will understand that movement of the vehicle is not necessary in order to practice the present invention. For example, the sensed turning condition for energizing filament  14  may be determined solely upon the position of wheels  30 , a turn signal switch, speed, or some combination of the foregoing. For example, even when the wheels are in a generally forward configuration, it may be desired to provide addition lighting as the speed of the vehicle increases. In yet another example, vehicle speed is combined with other input, such as wheel position to provide a sensed turn condition. Thus, at a lower speed, a slight turn will not result in filament  14  being energized, while the same turn at a higher speed results in filament  14  being energized. These and other variations are within the scope of the present invention.  
         [0016]    Referring now to FIG. 5, wheels  30  of vehicle  32  are shown turned even farther away from the generally forward configuration of FIG. 3. Thus, when moving, vehicle  32  would turn in a more severe turn than the turn shown in FIG. 4, in the direction indicated by arrow  48 . In accordance with the present invention, the turn is sensed as having exceeded a threshold, and filament  14  is energized. Thus, illumination is provided by filament  14  to area  46 . However, because the sensed turn exceeds a second threshold, filament  16  is also energized. Thus, illumination is provided by filament  16  to area  50 . Similar to the first threshold, a variety of sensed conditions may be used jointly or independently in defining the second threshold.  
         [0017]    While the present invention has been described in detail with reference to certain exemplary embodiments thereof, such are offered by way of non-limiting example of the invention, as other versions are possible. By way of example, but not of limitation, the fixture may include more than one optical axis. Thus, one filament may be used predominantly to provide light along a first optical axis, and a second filament may be used predominantly to provide light along a second optical axis. Those of skill in the art will recognize that a lens with multiple prescriptions and/or a reflector with multiple prescriptions may be used to define multiple optical axes. Moreover, a number of design choices exist within the scope of the present invention. For example, the filament may be oriented or located in a variety of positions within the fixture. Additionally, the fixture may be located within an assembly dedicated to bending light, or incorporated into a combined forward lighting/bending lighting unit. It is anticipated that a variety of other modifications and changes will be apparent to those having ordinary skill in the art and that such modifications and changes are intended to be encompassed within the spirit and scope of the invention as defined by the following claims.