| 摘要 |
PURPOSE:To adjust an optical axis with no hunting, precisely, and quickly by comparing and judging whether the optical axis detection voltage lies between the upper and the lower limit set voltages by a window comparator having hysteresis characteristics. CONSTITUTION:When selective switches SW1, SW2 are operated to direct the optical axis of headlamps 7 in the direction corresponding to the load applied to a car, the upper and the lower limit reference voltages VRH, VRL are fed to a window comparator 5 from a setter 4. The optical axis voltage VIN across a variable resistor 3 is compared with them, and if it is lies within both reference voltages, a motor 1 and an optical axis drive unit 2 are not operated. When it exceeds the range, an OP amplifier 5a or 5b output is made H, a transistor Tr1 or Tr2 is made ON to switch relays Ry1, Ry2, and the motor 1 is rotated positively or reversedly to adjust the optical axis. Thereby, the optical axis can be adjusted without generating hunting, simply and quickly. |
