The tapered macrogate (TMG) structure is proposed to overcome the difficulties in carbon nanotube (CNT) based field emission display (FED) with high-voltage phosphors used in cathode ray tube screens. In order to achieve an ideal triode operation for field emission devices, the TMG was designed to have a very thick gate insulator with the inclined gate holes compared with the CNT emitters. The inclined gate holes with a narrower outlet than the bottom of the hole were shown to protect the CNT emitters from the anode field perfectly, enabling the authors to apply a high anode voltage over 10 kV needed for high-voltage FED. Also, the TMG structure had additional useful functions such as an electron-beam self-focusing and high durability against electrical damage. The authors successfully fabricated and demonstrated a 5 in. active-matrix CNT-FED panel with the TMG, showing color moving images with a low addressing voltage of about 15 V using amorphous silicon thin-film transistor as a switching device.