Oled display device and method for partterning cathodes of the device

An OLED display device (20; 62; 82) and a method of fabricating the device utilize a patterned layer of conductive pads (26, 28 and 30; 64, 66 and 68) formed over a substrate (22) to fabricate a cathode layer (32, 34, 36 and 38; 70) without the need to subsequently pattern the-cathode layer to create individually addressable cathodes. The design of the OLED display device is such that the cathode layer is positioned below the anode layer (42). The OLED display device may be configured to emit light through the substrate or through the top layer, i.e., the anode layer. In a first embodiment, the conductive pads have sharp edges that effectively pattern the cathode layer when it is formed over the pads. In a second embodiment, the conductive pads do not include sharp edges. In this embodiment, the cathode layer is made of a composite material, which includes cathode components and non-conducting components. The composite material allows the resulting cathode layer to have the desired characteristics to effectively inject electrons vertically into the EL region (40) of the device, while limiting lateral conduction between the conductive pads.