Patent ID: 7268476

Claim:
A field emission electron source comprising an insulative substrate and an electron source element formed on the side of one surface of said insulative substrate, said electron source element comprising: a lower electrode; a surface electrode; and a strong-field drift layer including polycrystalline silicon and disposed between said lower electrode and said surface electrode, said strong-field drift layer allowing electrons to pass therethrough according to an electric field generated when a certain voltage is applied to said lower and surface electrodes in such a manner that said surface electrode has a higher potential than that of said lower electrode, said field emission electron source comprising: a buffer layer provided between said strong-field drift layer and said lower electrode, said buffer layer having an electrical resistance greater than that of said polycrystalline silicon, and said buffer layer being composed of a film which is uniformly formed over the whole area on the side of said surface of said insulative substrate.