This article addresses triple-junction issues related to vacuum insulation in field emission displays (FEDs), both from a theoretical and practical point of view. A technique to inhibit the triple-junction initiated breakdown in dielectric spacer insulation has been demonstrated. In order to simulate the vacuum insulation structure in a FED, thin-film electrodes bridged by a thin-wall-structured spacer were used. Using the developed technique, the breakdown voltage was improved from similar to 10 to similar to 21 kV for the first run and similar to 13 to 24 kV for the conditioned regime. The mechanism of breakdown of the solid insulator is discussed.