US Patent 7422674 Method of producing structures by anodizing

Provided are electron-emitting devices improved in durability during concentration of an electric field and thus rarely suffering chain discharge breakdown. An electron-emitting device has an electroconductive film, a layer placed on the electroconductive film and containing aluminum oxide as a main component, a pore placed in the layer containing aluminum oxide as a main component, and an electron emitter placed in the pore and containing a material of the electroconductive film, and the electron emitter is porous and is electrically connected to the electroconductive film.