Optimization of electron beam focusing for CNT-FEDs

An electron beam focusing was optimized to obtain high color purity in 38" high definition level carbon nanotube-field emission devices (CNT-FEDs). We could successfully adopted the focusing structure where each CNT dot is aligned to a gate and a focus gate hole, which results in electric field symmetry and makes it easy to focus electron beam. The structure also has a concave geometry. By varying the sizes of the focus gate hole, the optimum I-V conditions are obtained. The fine electron beam focusing even under wide e-beam divergence of CNTs could be achieved.