Field emission neutralizer

Patent metadata

Field	Value
Publication number	US-11215171-B2
Application number	US-201916661180-A
Country	US
Kind code	B2
Filing date	Oct 23, 2019
Priority date	Jul 16, 2019
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

A field emission neutralizer is provided. The field emission neutralizer includes a bottom plate and a field emission cathode unit located on the bottom plate. The field emission cathode unit includes a substrate, a shell located on the substrate, a cathode emitter located inside the shell, a mesh grid insulated from the cathode emitter, and a shielding layer insulated from the mesh grid. The cathode emitter includes a cathode substrate and a graphitized carbon nanotube array. The graphitized carbon nanotube array is in electrical contact with the cathode substrate. The graphitized carbon nanotube array is fixed on a surface of the substrate body, and the carbon nanotubes of the graphitized carbon nanotube array are substantially perpendicular to the cathode substrate.

First claim

What is claimed is:

1. A field emission neutralizer comprising:
a bottom plate; and
at least one field emission cathode unit located on the bottom plate, each field emission cathode unit of the at least one field emission cathode unit comprising:
a first substrate;
a shell located on the first substrate and comprising an opening, wherein a material of the shell is a conductive material, the shell comprises a first surface and a second surface opposites to the first surface, and the first surface directly contacts with the first substrate;
a cathode emitter located in the shell, and comprising a second substrate and a graphitized carbon nanotube array, wherein the graphitized carbon nanotube array comprises a plurality of carbon nanotubes, and wherein the graphitized carbon nanotube array is super aligned and electrically connected with the second substrate; and
wherein a majority of the plurality of carbon nanotubes are parallel to each other and perpendicular to the second substrate, and a few randomly arranged carbon nanotubes exist in the graphitized carbon nanotube array, and the few randomly arranged carbon nanotubes do not affect an overall orientation of the plurality of carbon nanotubes;
a first insulating layer located on the second surface of the shell and comprising a first through-hole;
a mesh grid comprising a plurality of gate holes and located on a surface of the first insulating layer away from the second surface of the shell, wherein the mesh grid is insulated from the cathode emitter; and
a shielding layer comprising a second through-hole and being electrically insulated from the mesh grid,
wherein the shell, the first insulating layer, and the mesh grid are stacked with each other, the opening, the plurality of gate holes, the first through-hole and the second through-hole communicate with each other, the graphitized carbon nanotube array is fixed on a first surface of the first substrate, and the plurality of carbon nanotubes of the graphitized carbon nanotube array are perpendicular to the second substrate.

2. The field emission neutralizer of claim 1 , wherein the second substrate comprises a substrate body and an adhesive layer, and the graphitized carbon nanotube array is fixed on a second surface of the substrate body by the adhesive layer.

3. The field emission neutralizer of claim 2 , wherein the graphitized carbon nanotube array defines a first end and a second end opposite to the first end, the plurality of carbon nanotubes of the graphitized carbon nanotube array extends from the first end to the second end, and the first end of the graphitized carbon nanotube array is inserted into the adhesive layer.

4. The field emission neutralizer of claim 1 , wherein the cathode emitter comprises a plurality of graphitized carbon nanotube arrays, and the plurality of graphitized carbon nanotube arrays are spaced apart and fixed on the substrate body.

5. The field emission neutralizer of claim 1 , wherein the graphitized carbon nanotube array is free of impurities.

6. The field emission neutralizer of claim 1 , wherein 50% to 80% of the plurality of carbon nanotubes of the graphitized carbon nanotube array are graphitized, wherein 50% to 80% is a quantity percentage of the plurality of carbon nanotubes.

7. The field emission neutralizer of claim 1 , wherein the graphitized carbon nanotube array is a three-dimensional ordered graphite structure.

8. The field emission neutralizer of claim 1 , wherein the first insulating layer is an insulating plate or a plurality of insulators located between the shell and the mesh grid.

9. The field emission neutralizer of claim 1 , wherein the first insulating layer is an insulating plate, the insulating plate comprises a third through hole, and the third through hole and the opening on the shell communicate with each other.

10. The field emission neutralizer of claim 1 , wherein a distance between the mesh grid and the cathode emitter ranges from 100 micrometers to 200 micrometers.

11. The field emission neutralizer of claim 1 , wherein the shielding layer is a stainless steel plate.

12. The field emission neutralizer of claim 2 , further comprising a conductive layer, wherein the conductive layer is electrically connected with the substrate body.

13. The field emission neutralizer of claim 1 , wherein the field emission neutralizer configured for operation in a vacuum.

14. The field emission neutralizer of claim 2 , wherein the substrate body is fixed to a side wall of the shell by binder or screw bolt.

15. The field emission neutralizer of claim 1 , wherein the first substrate, the shell, the first insulating layer, the mesh grid, and the shielding layer are fixed together by adhesive, welding, or screws.

16. The field emission neutralizer of claim 5 , wherein the graphitized carbon nanotube array is free of catalysts used in a process of growing the graphitized carbon nanotube array.

Assignees

• Univ Tsinghua
• Hon Hai Prec Ind Co Ltd

Inventors

• Liu Peng
• Zhou Duan-Liang
• Zhang chun-hai
• Qian Li
• Wang yu-quan
• Guo Xue-Wei
• Ma li-yong
• Wang fu-jun
• Fan Shou-Shan

Classifications

• C01B2202/36

  Diameter · CPC title

• F03H1/0025 Primary

  Neutralisers, i.e. means for keeping electrical neutrality · CPC title

• H01M4/583

  Carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• F03H1/005

  using field emission, e.g. Field Emission Electric Propulsion [FEEP] · CPC title

• C01B32/168

  After-treatment · CPC title