Abstract: A thin film light emitting device comprises a substrate (21), a first substantially flat electrode (22) deposited continuosly over a substantial portion of a surface of the substrate (21), a second electrode (25), a substantially flat electroluminescent layer (24) sandwiched between the first (22) and second (25) electrodes, and an insulating layer (23) sandwiched between the second electrode (25) and the electroluminescent layer (24). The insulating layer (23) is patterned to provide contact areas between the second electrode (25) and the electroluminescent layer (24). The contact areas lie wholly within the area of the first electrode (22) and define the shape of an area over which light is emitted when a DC voltage is applied between the first (22) and second (25) electrodes. One or more further substantially flat electrically active layer(s) may be deposited between the first electrode (22) and the insulating layer (23).