Single filament, dual function, vehicle signal lamp

Claim 1

A single filament dual function vehicle signal lamp assembly adapted to be connected to vehicle safety light signalling or illuminating circuits to serve functions previously served by dual filament vehicle lamps including tail and stop/turn lamp functions and the like, comprising a rear backing housing member serving as a reflector and lamp housing having a forwardly facing cavity bounded by a concavely curved reflector surface, a lens cover member joined about its perimeter to the housing member to cover said cavity, a single filament lamp bulb in said cavity, a generally flat annular electronic circuit board mounted in said housing in the form of an interrupted ring shaped to encircle said cavity and reflector surface inwardly adjacent the lens cover, at the perimeter of the cavity, said circuit board having a pair of unidirectionally conductive diodes and an elongated resistor element rigidly mounted on said board and connected to said lamp bulb and to external connectors to be interconnected with tail and turn/stop control circuits of the associated vehicle, said diodes and resistor element being interconnected to apply a higher voltage to the lamp bulb filament through one diode for turn or stop signal functions at a relatively brighter light intensity and applying a lower voltage to the filament through the other diode and resistor element for tail lamp signal functions at a relatively dim light intensity.