SWITCHING METHOD OF MAIN AND AUXILIARY BEAMS FOR DISCHARGE LAMP HEADLIGHT

摘要

PURPOSE:To switch a main beam and an auxiliary beam in a headlight using a discharge lamp as a light source by selecting an auxiliary beam reflecting face and a main beam reflecting face with a hood covering nearly the half-periphery of the discharge lamp and rotated using the optical axis of a reflecting mirror as an axis. CONSTITUTION:A rotary parabolic auxiliary beam reflecting face 3a having a focal point F1 backward in the radiation direction from the arc center 2a of a discharge lamp 2 nearly on the upper half section and a rotary parabolic main beam reflecting face 3a having a focal point F2 coinciding with the arc center 2a on the lower half section are formed on the reflecting mirror 3 of a headlight 1. A nearly half-cylindrical hood 4 covering nearly the half-periphery of the discharge lamp 3 is fitted to the discharge lamp 2 so that its center axis is rotated coincidentally with the optical axis X of the reflecting mirror 3. When the main beam is switched to the auxiliary beam, the reflected light from the auxiliary beam reflecting face 3a is made slightly downward because the hood 4 is located so as to cover the lower half face of the discharge lamp 2. Beams of the headlight using the discharge lamp as the light source can be switched.