Patent ID: 6486609
Filing Date: 2002-11-26
Classification: H01J

Abstract:
An electron-emitting element comprising:an electron conveying member; a cathode electrode comprising an electron-emitting member fixed to the electron conveying member; an anode electrode disposed such that it is spaced from the cathode electrode; and a grid electrode disposed between the cathode electrode and the anode electrode and having an electron passage opening; wherein the spatial positioning of the three members, the cathode electrode, the anode electrode and the grid electrode, and their respective shapes are constructed such that at least an equipotential surface including a grid electrode surface of an electric field generated between the grid electrode and the anode electrode protrudes toward the cathode electrode side and emanates from the electron passage opening to the cathode electrode side, and the emanated electric field and an electric field generated between the cathode electrode and the grid electrode interact with each other to form a combined electric field; and electron-emission controlling means is provided for varying the intensity of the combined electric field by varying at least the potential of the grid electrode to control the number of electrons emitted from the cathode electrode.