We investigated new triode-type field emission arrays (FEAs) and an appropriate driving method in a lower plane (cathode plate) for a flat lamp applicable to backlight units (BLUs) in liquid crystal display (LCD). The proposed triode-type FEAs were designed with a gate and cathode on the same lower plane without distinction, and a `swap-gate driving' method was applied to obtain field emission uniformity and a longer emitter lifetime. A 3-in.-diagonal flat lamp for a LCD BLU was fabricated using carbon nanofibers grown by plasma-enhanced chemical vapor deposition at approximately 480 °C. A white-phosphor luminance of 10,000 cd/m2 was obtained when the gate-voltage amplitude, gate frequency, and duration time were 230 Vamp, 25 kHz, and 2.0 µs, respectively, with an anode voltage of 10 kV and an anode-cathode spacing of 10 mm.

The relationship between base layers beneath a Ni catalyst and carbon nanofiber (CNF) growth was investigated at a deposition temperature of about 480 C using a direct-current plasma-enhanced chemical vapor deposition system. Amorphous carbon was deposited on some base layers such as Pt, Ni, Cr, and W, while CNFs were grown on other base layers such as Ag, Mo, Cu, Al, and Ti. In order to explain why CNF growth on some base layers such as Pt, Ni, Cr, and W is absent, a new model unlike existing ones, related to the charge transfer rates of materials, was proposed on the basis of results of scanning electron microscopy, atomic force microscopy, energy-dispersive X-ray spectroscopy, and phase diagram analysis.

On the basis of new triode-type field emission arrays (FEAs) and the so-called swap-gate driving method for a 3-in.-diagonal flat lamp using carbon nanofiber (CNF) emitters in our previous research, the characteristics of our flat lamp were investigated according to the swap-gate driving conditions. It was found that the longer the gate-pulse width (duration time), the higher the anode current. Additionally, in the case of a fixed gate-pulse width, the anode current increased as the gate frequency increased. One particularly interesting experimental result was that the emission current (I a ) increased with the shortening of the pulse width of the gate when the sum of the gate-pulse widths per second was equal.

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