Illumination – Supported by vehicle structure – Projection-type headlamp
Reexamination Certificate
1999-07-06
2001-05-08
Quach, Y. (Department: 2875)
Illumination
Supported by vehicle structure
Projection-type headlamp
C362S465000, C362S514000
Reexamination Certificate
active
06227691
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a headlight arrangement for a motor vehicle.
More particularly, it relates to such a headlight arrangement which has a reflector subdivided into several reflector regions, a light source arranged in the region of the apex of the reflector, so that light which is emitted by the light source is reflected by the reflector on a roadway in front of the motor vehicle, and at least one screening device associated with at least one selected reflector region. The screening device is adjustable between a passage position in which the light emitted by the light source can reach the selected reflector region, and a screening position in which it screens the reflector region from the light emitted by the light source.
In such headlight arrangements, the reflector can be subdivided however into several desired functional reflector regions. The subdivision must not be visible from outside, for example as steps between the reflector regions. Such headlight arrangement is disclosed for example in the German patent document DE 43 07 110 A1. The lateral reflector regions of the open headlight arrangement disclosed in this reference influence the side dispersion, the upper and lower reflector region influence the pre-field illumination.
For switching of the known headlight arrangement from the right side traffic to the left side traffic and vice versa, the headlight arrangement is provided with at least one screening device which screens the lateral reflector regions from the light source so that an asymetric illumination intensity distribution is produced with the bright-dark limit increasing toward the roadway edge at the road side itself (in other words right for the right side traffic and left for the left side traffic).
While the screening devices in accordance with the prior art can be switched between the passage position and the screening position, an intermediate position is not provided in them. The screening device disclosed in the German patent document DE 43 07 110 A1 can be switched between the two positions for the right side traffic and left side traffic. The headlight arrangement has the same statistic light distribution for the right side traffic and the left side traffic. However, for an asymmetrical illumination intensity distribution the bright-dark limit at the roadway side raising toward the roadway edge can be switched for the right side traffic to the right and for the left side traffic to the left.
It has been however recognized that there is no optimal statistic illumination which can be correct for all road and traffic situations. For example, during driving on a speedway with a high speed another optimal light distribution is required by governmental regulations that during driving with a lower speed. Therefore, a headlight arrangement would be desirable, in which the light distribution can be controlled adaptively, or in other words in correspondence with the road and traffic situations.
A so-called curve headlight is known from the prior art and has turnable reflectors for variation of the dispersion width. With such a curve headlight the roadway edges during driving over curves can be illuminated wider. Moreover, free-standing individual headlights are known, which are arranged at the right side and the left side of the motor vehicle and provide illumination in the side regions. By turning on and turning off of the individual headlights, the side width of the vehicle can be illuminated as desired.
In the known curve headlights disclosed in the prior art, the construction is substantially large because of the adjustment mechanism and the turnable reflectors. Moreover they take into consideration only the steering angle as a single control value for the light distribution. Finally, the turnable reflectors are subjected to wear and must be maintained in regular time intervals. Due to the turnable reflectors and the broadly fluctuating environmental conditions (temperature, air moisture, dirt) in the headlights, the known curve headlight is especially sensitive.
The lateral single headlights in accordance with the prior art has a disadvantage that they are fixedly mounted on the motor vehicle. They have no flexibility with regard to the light distribution. They are either turned on and illuminate the side regions or they are turned off and do not illuminate the side regions. Intermediate positions which can be desirable for illumination of only predetermined parts of the side regions for illumination of side regions with variable intensity, are not provided. The known single headlights require a mounting space in the motor vehicle.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a headlight arrangement for a vehicle, which avoids the disadvantages of the prior art.
More particularly, it is an object of present invention to provide a headlight arrangement for a vehicle, which makes possible an adaptive light distribution, has a simple construction, operates reliably and at the same time has small dimensions.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a headlight arrangement which it has a control unit controlling the screening device in dependence on vehicle sensor signals and the screening device is adjusted steplessly so that for each vehicle situation an optimal light distribution is provided.
Vehicle sensor signals which can be considered for use for the control unit to control the screening device include for example the vehicle speed, the motor rotary speed, the selected gear, the steering angle, the vehicle inclination, the yawing rate, the spring path, the adjustment of the gas pedal, the adjustment of the brakes, the outside temperature and/or the air moisture. In a particularly advantageous manner, as a vehicle sensor signal also a street traffic can be introduced, which is determined by a navigation system. Basically, all physical conditions which can have an influence on the vehicle condition can be determined by a sensor and supplied to the control unit. From the steering angle course in connection with the vehicle speed, for example the roadway course can be determined. In particular, curves can be recognized and the headlight arrangement can illuminate the curves correspondingly. From the spring path, for example the roadway quality can be determined and the light distribution can be correspondingly controlled.
The control unit determines from the vehicle sensor signals the vehicle situation and correspondingly controls the screening device. For example low speeds mean frequently changing actuation of the gas pedal and the brake pedal and frequent curves during a city driving. High speeds over a long time interval with insignificant steering wheel action means the speedway driving, and corresponding greater steering wheel action means driving on a highway. Further vehicle situations include for example the vehicle inclination about the longitudinal axis during driving over curves, or the vehicle inclination about the transverse axis during acceleration or braking. Moreover, the driving over curves is a vehicle situation which requires a special light distribution. Finally, the exterior conditions, weather and environmental conditions, produce a vehicle situation which requires a special light distribution. An optimal light distribution means that, depending on the corresponding vehicle situation, the prescribed and standard requirements are fulfilled on the one hand, but on the other hand with regard to the light distribution, they are completely satisfied.
The inventive headlight arrangement can control the light distribution correctly in accordance with the situation, depending on the street, driver, and vehicle situation, and therefore guarantees a substantial contribution to improvement of the street safety. At lower speeds, the side region of the vehicle and in some cases also the adjoining region in front of the vehicle are illuminated better, w
Hogrefe Henning
Schlienz Friedemann
Quach Y.
Robert & Bosch GmbH
Striker Michael J.
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