US Patent 7791263 Electron emitting structure by field effect, with emission focussing

An electron emitting structure that emits electrons by field effect, including: at least one electronic emission zone indicated by a cathode electrode positioned according to a first axis and an extraction gate electrode positioned in a second axis, with an electrical insulating layer separating the cathode electrode from the gate electrode, wherein the electronic emission zone includes a plurality of electron emitting elements electrically connected to the cathode electrode, wherein the electron emitting elements are disposed in rows in openings in the gate electrode and the electrical insulating layer, the gate openings are disposed in rows between two bands of the gate electrode; and focussing means for focusing electronic beams emitted by the electron emitting elements.