A field emission device (5) includes cathode electrodes (51), emitters (52) formed on the cathode electrodes, grid electrodes (54) formed over the cathode electrodes at a distance apart from the emitters, and isolated films (55) formed on surfaces of the grid electrodes neighboring the emitters. Preferably, the isolated film has a thickness ranging from 0.1 to 1 microns. The isolated film may be a film made of one or more insulating materials, such as SiO2 and Si3N4. Alternatively, the one or more insulating materials can be selected from a material having a high secondary electron emission coefficient, such as MgO, Al2O3 and ZnO. Additionally, the isolated film can be further formed on a second surface of the grid electrode distal from the emitter.