Patent ID: 7005783
Filing Date: 2006-02-28
Classification: H01J

Abstract:
1. A device, comprising: a substrate having a cavity that extends into the substrate, the cavity having an opening on at least one surface of the substrate; an anode positioned within the cavity of the substrate; a cathode comprising a first insulating layer positioned above the opening of the cavity, wherein the anode receives electrons emitted by the cathode, and wherein the anode produces an electrical current to an external source in response to receiving the electrons; a first grid having at least one aperture to allow the passage of electrons therethrough, wherein the first grid is constructed of an electrically conductive material, and wherein the aperture of the first grid is positioned between the cathode and anode; a second grid having a plurality of apertures configured for allowing the passage of electrons therethrough, wherein the aperture of the second grid is positioned between the cathode and anode, and wherein the second grid controls the flow of electrons from the cathode to the anode when a control voltage is applied to the second grid; a seal for creating a controlled environment in an area surrounding the first grid, the cathode and the anode, wherein the controlled environment allows for electron flow between the cathode, first grid and anode; a circuit for heating the cathode, and a control circuit for controlling the magnitude of the flow of electrons through the aperture of the first grid, thereby controlling the electrical current produced by the anode.