ES343048A1 - Electric Incandescent Lamp for Car Lights - Google Patents

Abstract

An incandescent lamp for use in car headlights comprises a substantially cylindrical bulb 2 having an outside diameter not greater than 14 mm. and containing helical main and dipping filaments 5, 6 substantially in line with each other and separated by a distance a not greater than 4 mm., the dipping filament 6 being situated nearer the pinch or base 3 of the lamp and being shielded by a screen 13 substantially coinciding with the surface of the bulb and extending through an angle of 160-180 degrees about the filament. The screen preferably comprises a coating of paint on the bulb but may consist of a loose cap. The axis of the dipping filament may be spaced from the axis of the bulb by a distance at least half of the diameter of the filament, and in the preferred embodiment the main filament is similarly spaced. The lamp, which may be of the regenerative cycle type, is disposed in a parabolic reflector with the inner end of the main filament substantially coincident with the focus of the reflector. The mouth of the reflector is covered by a glass guard (Fig. 4, not shown) the lower half (21) of which is vertically profiled to spread the beam laterally. A segment (22) of the guard is of prismatic form and produces an asymmetrical zone of high intensity in the beam.