US Patent 7560860 Light emitting device including multiple light emitting layers

There is provided an active matrix type light emitting device which can be easily made multicolored. In a pixel portion of the light emitting device, a plurality of light emitting layers shared by a plurality of pixels are formed, so that a display of a plurality of colors becomes possible. Further, a preliminary region is provided in a region interposed between different light emitting layers, so that poor quality can be prevented from being produced due to a mask shift or the like at the time of formation of the light emitting layers. Further, a light emitting layer made of a triplet compound is used so that reduction in electric power can be realized.