Antiglare bulb shade for a vehicle headlamp

Abstract

An antiglare vehicle headlamp has an electric lighting bulb disposed in a lighting chamber defined by a lamp body and a cover lens secured thereto. A generally concave reflector is aimably mounted in the lighting chamber for reflecting the light rays from the bulb along the optical axis of the headlamp. The bulb has a substantially tubular envelope portion of vitreous material containing a filament, and a flat base portion formed in one piece with the envelope portion. As the base portion is conventionally formed by pinch sealing, a generally tapering part of indefinite shape and wall thickness is created between the envelope portion and the base portion. The indefinitely tapering part will refract in various directions the light rays emitted by the bulb filament. Should they be subsequently reflected by the reflector, such random light rays would not travel parallel to the optical axis, and some of them, issuing upwardly from the headlamp, would cause glare. A light shade is disposed between the bulb and the reflector for cutting off such glare causing ones of the light rays that have traversed the indefinitely tapering part of the bulb. Another embodiment is disclosed in which the lamp body has its inside surface rendered reflective, thereby dispensing with a separate reflector. The light shade is formed directly on the reflective surface of the lamp body.