Patent ID: 7736542

Claim:
A method for emitting electrons from an electron-emitting element comprising an electron-emitting sheet material, a conductive gate layer, and an insulating layer, wherein the electron-emitting sheet material comprises a substrate and a graphite sheet laminated on the top of the substrate, and wherein (1) the graphite sheet has a layered structure of layers of graphenes consisting of a plurality of carbon hexagonal networks, (2) the graphenes are layered relative to one another so that the c-axial direction of each graphene is substantially perpendicular to the plane of the substrate, (3) the graphite sheet is laminated on the substrate so that the c-axial direction of each graphene is substantially perpendicular to the plane of the substrate, and (4) the graphite sheet comprises an element other than carbon as a second element, and wherein the graphite sheet and conductive gate layer are arranged with an insulating layer therebetween; the method comprising the step of: emitting electrons from the electron-emitting element by generating a potential difference between the graphite sheet and the conductive gate layer.