US Patent 10424761 Electroluminescent display device

An electroluminescent display device includes a substrate including an emissive area and a non-emissive area, a plurality of protrusions over the substrate and in the emissive area, each of the plurality of protrusions spaced apart from each other with an air gap therebetween, a high-viscosity material layer on the plurality of protrusions and the air gaps, a first electrode on the high-viscosity material layer, an emitting layer on the first electrode, and a second electrode on the emitting layer.