Single arc discharge headlamp with light switch for high/low beam operation.

摘要

An arc discharge headlamp system employs a single continuously operating arc discharge source to provide both high and low beam patterns. The continuously operating arc discharge increases lamp life and eliminates the problem in arc light source headlamp systems of momentary dimming when switching to high beam operation due to mercury condensing within source. The headlamp (10) has an arc light source (14) mounted horizontally within a reflector (12). Light from the arc light source is reflected by the reflector through a lens (15) to form a low beam pattern. A mirror (22) within the reflector is positioned to form a virtual image (24) of the light source, which is directed towards a second lens (26) concentric with the first lens to form a high beam pattern when combined with the low beam pattern. Switching between the high beam and low beam patterns is accomplished in a variety of ways. In the preferred embodiment, the second lens incorporates an electrically responsive light valve (34) which either passes or blocks the virtual image of the arc light source. Alternatively, the mirror may be moved between a position that directs the virtual image through the lens to a position where the virtual image is not directed through the lens. Rather than moving the mirror, it may be blocked with a mask during low beam operation. <IMAGE>