A novel approach for focusing electron beams using low-cost ceramic grid [field emitter arrays]

A low-cost ceramic grid was used as a stand-alone focusing electrode in field emitter arrays to obtain high brightness and small electron beam size. The ceramic grid with an array of 200-μm holes was made from DuPont 591 with low-cost equipment. Beam size is controllable by the voltage applied to the focusing grid. Light intensity profiles were measured and analyzed. The full width at half maximum (FWHM) of the light profile excited by electron emission from 30-μm wide field emitter arrays is 60 μm at 5000 V with 6 mm anode-cathode separation. At an anode voltage of 2000 V and gate voltage of 55 V, focusing is optimized at a focusing voltage of 30 V. Arc-free operation at 10 kV was achieved, thereby promoting improved phosphor efficiency. This focusing approach may lead to improve lifetimes for field emission displays and other vacuum microelectronic devices by significantly increasing the total vacuum volume and providing a means for improved getter utilization