US Patent 6913375 Lamp masking method and apparatus

A motor vehicle lamp assembly having a light source for emitting light and a source enclosure having a light transmissive portion for transmitting light from the light source to an illumination zone. The enclosure is affixed with a material which covers a selected region of the light transmissive portion of the enclosure. The material is electrically energized to alter an amount of light transmitted from the light source to the illumination zone. A drive circuit electrically coupled to the material energizes the material to control a light output from the lamp assembly.