| 摘要 |
PURPOSE:To aim at the prolongation of service life in a headlight, by installing a discharge lamp for dimmed light radiation use and an incandescent lamp for selection of low-beam light and driving light radiation as a whole, while constituting a device so as to turn off the incandescent lamp's dimmed light immediately after the discharge lamp coming into stabilized glowing. CONSTITUTION:With a glow starter switch 21 turned on, symmetrical metal halide lamps 7 start to glow via paired starting circuits 13, while each of dimmed light filaments 16 of symmetrical tungsten halogen lamps 14 is lighted. Immediately after lighting, as these metal halide lamps 7 are still unstable, the quantity of light emission in each of lamps 7 is small but the light quantity is compensated with these dimmed light filaments 16 lighted, so that a vehicle can keep up its starting readiness. When these metal halide lamps 7 are stabilized for light emission, a timer 26 inside a control circuit 23 is set in motion whereby a continuous rating current for these dimmed light filaments 16 of the tungsten halogen lamps 14 is cut off, turning off them. With this constitution, the quantity of light capable of starting the vehicle at once is secured, thus the prolongation of service life in the headlight is well promoted. |
