A color field emission display was developed with active-matrix cathodes and tapered macro-gate (TMG). The cascade-connected a-Si TFTs exhibited well controlled field emissions from carbon nanotube (CNT) emitters. The TMG protected the CNT emitters from the anode field perfectly, enabling us to apply a high anode voltage over 10 kV. IntroductionSince the first application of carbon nanotube (CNT) as an electron source, there were many attempts to make CNT-field emission display (FED) [1][2][3][4]. To construct uniform and reliable CNT emitters is one of the critical issues. Furthermore, a very high anode-accelerating voltage is essential in FED to guarantee commercial brightness, lifetime and efficiency in the absence of low voltage phosphors. The commercially available phosphors need very high energy electrons above 7 KeV, which in turn requires high anode voltage architecture in FED.We proposed that an active-matrix (AM) cathode with thin-film transistor (TFT) could be a good choice for FED, and demonstrated mono AM-FEDs [5][6][7]. Also, the mesh gate structure along with the AM cathode of a-Si TFTs and CNT emitters was proposed [6][7], and here we renamed it the tapered macro-gate (TMG) to clarify its function compared with general mesh structure. The TMG has relatively tall and tapered holes compared with CNT emitters, protecting the CNT emitters from the anode field perfectly.In this paper, a new AM cathode is proposed to further improve the intra-pixel uniformity of FED. The developed color AM-CNT FED with TMG was successfully operated with a good uniformity. Figure 1 shows the new AM cathode structure with cascadeconnected a-Si TFTs and CNT emitters. The address TFT, addressing the display signals, and the driver TFT, driving the CNT emitters directly, are series-connected. The address TFT has the normal gate structure meanwhile the driver one has the offset gate with an offset length (L off ) to endure a high voltage needed for field emission through the TMG. The TMG with tapered gate holes not only induces field emissions but also shields the CNT emitters from the anode voltage perfectly, enabling us to apply a very high anode voltage of about 10 KV in high-voltage FED technology. New AM Cathode DesignThe equivalent sub-pixel circuit of the proposed AM cathode is shown in Fig. 2. A single address TFT and multiple driver TFTs have been incorporated in a sub-pixel in which each driver TFT had its own CNT emitters and controlled the CNT emitters separately. AM-CNT FED Fabrication and PerformancesConventional inverted-staggered process was applied to the fabrication of a-Si TFTs for our AM cathode along with 4-mask lithography, which is at least 1 less mask than the TFT-LCD process. The deposition conditions for the active and dielectric layers were adjusted to endure the high-temperature vacuum sealing process. An as-prepared multi-wall CNT powder was mixed with some organic binder, photo-resist, and conducting particles. The mixed CNT paste was formed onto the drain of driver TFTs using screen printing and...

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Highly reliable carbon nanotube (CNT) emitters were obtained by optimizing the paste composition along with a nano‐scale metal filler. The nano‐scale filler strongly enhanced adhesion between CNT emitter and cathode electrode. The developed CNT emitters showed great improvements in field emission properties including the effective density, uniformity, and reliability.