Carbon nanotube sheets used in field-emission lamps with vacuum-sealed diode structures

We applied carbon nanotube (CNT) sheets, which are high-purity and suitable for mass production, to field-emission lamps (FELs) with vacuum-sealed diode structures. Three such FELs were designed and fabricated to correspond to the field-emission characteristics of individual CNT sheets. We suppressed the variation in the anode–cathode voltage to within the range of 5.4–6.0 kV, which contributes to the light output of the FELs. The stabilities of the FELs ranged from −0.65% to 0.26% in the short term; therefore, we confirmed that the high-purity CNT sheets were stable during operation. All FELs could be operated for 500 h without significant degradation, even when the FEL was operated in a passive vacuum instead of a dynamic vacuum.