Automatically focusing field emission electrode
AssigneeSRI International
InventorCharles A. Spindt
Life of this patent
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Abstract
Several embodiments of a thin film field emission cathode array are described which automatically shape the beams of emitted particles, without the addition of shaping or other electrode structure. A potential field pattern is established to control the trajectory of the emitted particles, by controlling the electromagnetic interaction of the conductive structures responsible for the particle emission.
Claims21
A particle field emission structure comprising, in combination:
- at least one particle emission site having one or more emitting tips for electrically charged particles;
- an electrically conductive base structure positioned to provide electrical energy to said emitting tips for electrically charged particles to be emitted therefrom;
- an electrically conductive control electrode structure positioned at said site for controlling the extraction of particles from said site;
- means for applying a potential difference between said base structure and said control electrode to extract electrically charged particles from said particle emission site;
- said control electrode, base structure, and potential applying means being selected to have an electromagnetic interaction between said control electrode and said base structure providing both an extraction potential for said particles and automatically establishing a potential field pattern in the spatial volume adjacent said control electrode structure on the side thereof opposite said base structure which will provide desired trajectories therethrough of particles formed at said site.
The particle field emission structure of any of the previous claims, further including an electrical insulator structure at each of said sites between said electrically conductive base and said control electrode structure.
A method of generating electrically charged particles and controlling the initial trajectory thereof, comprising the steps of:
- A. Providing at least one particle emission site having one or more electrically charged particle emitting tips;
- B. Providing an electrically conductive base structure positioned to provide electrical energy to said emitting tips for electrically charged particles to be emitted therefrom;
- C. Providing an electrically conductive control electrode structure at said site for controlling the extraction of particles from the emitting tips thereat;
- and
- D. Controlling a potential difference between said base structure and said control electrode to extract electrically charged particles from said particle emission site and to automatically establish a potential field pattern which will interact with electrically charged particles in the spatial volume adjacent said control electrode structure on the side thereof opposite said base by selecting a desired electromagnetic interaction between said base and control electrode structures during the extraction of particles from said site.
A method of constructing a particle field emission structure which comprises the steps of:
- A. applying a layer of insulating material on one surface of a base structure;
- B. applying a generally continuous and planar layer of electrically conductive material on said insulating material with a plurality of spaced-apart apertures through said layers;
- C. forming electrically charged particle emission sites at said apertures;
- and thereafter
- D. removing substantially all of said layer of electrically conductive material between said sites to form a control electrode structure for electromagnetic interaction with said base structure to extract particles from said emission sites while enabling potential on said base structure to aid the formation of a potential field pattern in the spatial volume on the side of said control electrode structure opposite said base structure which will provide desired trajectories therethrough of particles formed at said sites.
Dependencies are inferred from the claim text.