Patent ID: 7791263

Claim:
An electron emitting structure that emits electrons by field effect, comprising: 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, the electron emitting elements are in rows in openings in the gate electrode and the electrical insulating layer, and the gate openings are in rows between two bands of the gate electrode; and focussing means for focusing electron beams emitted by the electron emitting elements, wherein the focussing means include a dissymmetrical layout of rows of the electron emitting elements and their adjacent gate electrode bands, and the dissymmetrical layout focuses all of the electronic beams and includes a difference in width of gate electrode bands adjacent to a same gate opening so that, for this same gate opening, the adjacent band situated closest to an outside of the electronic emission zone is narrower than the adjacent band situated the closest to an inside of the electronic emission zone.