The field emission cathode device includes an insulating substrate with a number of cathodes mounted thereon. A number of field emission units are mounted on the cathodes. A dielectric layer is disposed on the insulating substrate and defines a number of voids corresponding to the field emission units. The dielectric layer has an upper and lower section and disposed on the insulating substrate. The dielectric layer defining a plurality of voids corresponding to the field emission units. A number of grids disposed between the upper and lower sections, and wherein each grid are secured by the upper and lower sections of the dielectric layer.