A barrel-shaped metal/insulator/metal (MIM) field-emission cathode, also referred to as a field-emission cannon, is constructed using conventional SU-8 UV lithography combined with sputtering and lift-off processes. An array of these field-emission cannons has demonstrated uniform field emission in a luminescent pixel array. The field-emission test proves that the unique geometry of the field-emission cannon significantly improves field-emission efficiency and electron beam focus. Detailed data analysis has revealed that both conventional sharp edge field emission and MIM field emission contribute to the total emission current. The field emission starts from an edge emission at gate voltages (Vg) below 8 V. When Vg increases above 8 V, electrons tunnel into the cannon through the thin SiO2 layer and inner metal layer (i.e., the gate electrode). Thus, the MIM field emission starts to dominate.