Shapes of emitter surface in field emission display

Characteristics of various surface shapes of planar emitter in field emission display were investigated through computer simulations. Carbon nanotube emitters in field emission displays have the potential for low-cost manufacturing and stable emission sources. An over-gate triode structure with carbon nanotubes as the planar emitter is chosen to investigate its emission characteristics because this structure could shield and effectively pass the anode field down to the emitter. In triode structural field emission displays, the flat surface of emitters causes a non-uniformity of electric field strength on the emitter surface because of the thickness of emitter layer and the different distances of emitter sites from the gate electrode. For various shapes of emitter surface, we compare the density distributions of emission currents, trajectories of emission electrons and density profiles of the emitted beam on the anode plate, etc. By computer simulation we suggest the best shapes of the emitter surface for different driving modes and investigate their emission characteristics. These chosen shapes are expected to improve the emission uniformity without any damage to other emission properties such as the amount of emission current and the beam profile at the anode plate.