Controlling headlamp beam-width for vehicles

摘要

A procedure for controlling beam-width for a vehicle has a distance sensor and uses the following steps. At least one pulse signal is sent out by the sensor (2). An echo signal scattered by an obstacle is received. The time between the transmission and reception is determined and thus the distance of the obstacle from the sensor. Other steps are as follows. The time is determined for a "road reflex" of an inclined probing beam upon the road surface. The time taken is compared with a threshold and from the difference a correction signal is sent to the headlamps. When the car is started, the distance sensor is tilted for a certain time about an angle to the plane of the car to determine the time for this "road reflex" and then is set in a position where the probing beam is parallel to the plane of the road.