Planar lenses for field‐emitter arrays

Experimental data is analyzed for a method of collimating and focusing electron beams emitted from field‐emitter arrays (FEAs) where the focusing electrode is co‐planar or nearly co‐planar with the gate electrode. The focusing mechanism is provided by the fringe field formed along the edge of the gate electrode due to the potential difference between the grid and the substrate or the gate and another lens electrode. The concept is verified by EGUN2 simulations. Experiments performed to verify the theory and focusing of electron beams emitted from FEAs were observed. Emission data from 1×1, 1×100 and 2×100 arrays, located within long thin strips of gate electrodes are reported. Without focusing lenses, emission patterns on screen should have been approximately circular. However, elongated emission patterns were consistently observed, indicative of one‐dimensional focusing.