Device and method for controlling optical axis of headlamps

#This application claims priority from Japanese Patent Application Serial No. 2005-245679, filed on Aug. 26, 2005, No. 2005-293288, filed on Oct. 6, 2005, and No. 2006-033532, filed on Feb. 10, 2006, each of which is incorporated herein in its entirety by reference.

#The present invention pertains in general to a device and method for controlling an optical axis of headlamps.

#There are known devices for controlling vehicle headlamps. For example, in Japanese Kokai Patent Application No. 2002-326534, a steering angle sensor detects the steering direction of the vehicle and outputs a stepwise varying signal. The average of the steering angles detected by the steering angle sensor in multiple recent detection iterations is used to control the deflection angle of the headlamps.

#The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:

#FIG. 1 is a block diagram illustrating a device for vehicle headlamps in accordance with a first embodiment;

#FIG. 2 is a diagram illustrating a swiveling lamp actuator in accordance with the first embodiment;

#For the illumination device of vehicles such as that described in Japanese Kokai Patent Application No. 2002-326534, the steering angle sensor outputs the stepwise signal in increments of about 1° of the steering wheel angle, so that the swivel angle of the headlamps responds to even minute steering operations. This can cause the undesirable outcome of disconcerting the driver.

#According to embodiments of the invention, the vehicle speed and steering angle are detected, the light emission direction of the headlamps is computed based on the vehicle speed and the steering angle as well as a prescribed hysteresis value, and the light emission direction of the headlamps is controlled according to the computed light emission direction. Hence, in addition to the vehicle speed and steering angle, a prescribed hysteresis value is also used as a reference in computing the light emission direction of the headlamps, and the headlamps are moved into that light emission direction. The headlamps are not moved according to minute steering operations by the driver. As a result, the driver does not feel disconcerted or confused by minute movements of the headlamps.

#FIG. 1 is a block diagram illustrating one embodiment of a vehicle headlamp device. This vehicle headlamp device 1 has swivel control ECU (Electronic Control Unit) 11, ignition switch 12, headlamp switch 13, vehicle speed sensor 14, steering angle sensor 15, vehicle height sensor 18, acceleration sensor 19, yaw rate sensor 20, blinker detecting part 23, swiveling lamp actuators (left/right) 16a, 16b for swiveling lamps (left/right) 17a, 17b and navigation system 21.