| 摘要 |
PURPOSE:To achieve light control adaptable to the variation of travel environment by detecting abrupt change of illuminance occurring within unit travelling distance or time or the lighting period of illumination having predetermined lighting period and controlling power supply. CONSTITUTION:Upon approaching of car to a tunnel in daytime, external light and illumination are detected near the point B at the inlet, while upon approaching to the inlet, the illuminance will drop abruptly and when the voltage signal from A/D converter 3b reaches to the setting level e1, a computer 6 will start operation to provide a signal indicating the travelling distance or time until it will reach to e2 to a detection circuit 3c. If it is higher than the setting level X, output signal is not produced while upon feeding of pulse input of illumination in tunnel from a comparison circuit 5a, signals are fed from the output terminals 6a, 6b to drive the loads 10, 11. At the point C in tunnel, there is only illumination which is lower than the referential level e3 thus to continue driving. When the car passes behind an object or under illumination, the output voltage will drop and the pulse will not satisfy X conditions thus to never cause driving. |
