For resolving electron beam focusing and electric field breakdown between the anode and cathode plates in a high voltage field emission display (FED), the metal mesh grids are adapted in one body with spacers. The spacer charging mechanism is modeled in the real panel domain and confirmed by experiment. We analyze the morphology and the chemical composition modifications of the microtips in the narrow vacuum gap of a 5.2 in. FED panel, and infer possible degradation mechanisms in a FED device from our experimental data. The degree of oxidation formed on the microtip surface during fabrication and device operation is studied. Gas aging method for suppressing oxidation on the microtips and stabilizing phosphor is implemented for our 5.2 in. high voltage FED.