Analysis for charged spacers in FED

Charged spacers in the field emission display (FED) are analyzed with the Monte Carlo method. The spacer is made of an insulator, which has generally a high secondary electron emission property. Under electron bombardment, the secondary electron emission induces charge on the spacer. We show that the surface of the spacer is charged positively in FED operation, which would cause an image distortion. We analyze the effect of charging on the spacer in terms of the electron density profile and luminescence profile of a dot near the spacer. Simulation results show that the image of a dot near the spacer is darker and smaller than that of a dot away from the spacer, though electrons are crowded near spacers. The results are confirmed by experiments. Finally, we suggest a way to reduce the effect of spacer charging by introducing a metal strip.