Electron emission device and reflex klystron with the same

Patent metadata

Field	Value
Publication number	US-9305738-B2
Application number	US-201514749583-A
Country	US
Kind code	B2
Filing date	Jun 24, 2015
Priority date	Jun 25, 2014
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

An electron emission device includes an anode, a cathode, an electron emitter structure, and an electron extraction electrode. The cathode is spaced from the anode. The electron emitter structure is electrically connected to the cathode. The electron extraction electrode is insulated from the cathode. The electron extraction electrode defines a through hole surrounded by a sidewall, and the electron emitter structure faces to the sidewall. The electron emitter structure includes a number of electron emitters extending toward the sidewall, each of the number of electron emitters includes an electron emission terminal, a first distance between each electron emission terminal and the sidewall is substantially the same, a second distance between the electron emission terminal and the anode is greater than or equal to 10 micrometers and smaller than or equal to 200 micrometers, and a pressure in the electron emission device is smaller than or equal to 100 Pascal.

First claim

What is claimed is:

1. A reflex klystron, comprising:
a first substrate and a second substrate spaced from each other, wherein the first substrate and the second substrate are coupled together to form a resonant cavity;
a lens, wherein the lens is located on an end of the resonant cavity and configured as an output portion;
an electron emission device, wherein the electron emission device is configured to emit a plurality of electrons into the resonant cavity, the plurality of electrons are oscillated in the resonance cavity, and the electron emission device comprises:
an electron reflective structure on the second substrate, wherein the electron reflective structure comprises a reflective electrode and a second grid spaced from each other;
an electron emission structure on the first substrate, wherein the electron emission structure comprises a cathode, an electron extraction electrode, an electron emitter structure, and a first grid, the electron extraction electrode defines a through hole surrounded by a sidewall, the electron emitter structure comprises a plurality of electron emitters extending into the through hole, each of the plurality of electron emitters comprises an electron emission terminal, so that the electron emission structure has a plurality of electron emission terminals, first distances between the plurality of electron emission terminals and the sidewall are substantially the same, a second distance between each of the plurality of electron emission terminals and the reflective electrode is greater than or equal to 10 micrometers and smaller than or equal to 200 micrometers, and a pressure in the electron emission device is smaller than or equal to 100 Pascal.

2. The reflex klystron of claim 1 , wherein a difference between each two first distances is smaller than or equal to 50 micrometers.

3. The reflex klystron of claim 1 , wherein the through hole is in a shape of inversed funnel, the plurality of electron emitters are received into the through hole and space from the sidewall.

4. The reflex klystron of claim 3 , wherein the through hole defines a second opening and a fourth opening opposite to the second opening, the fourth opening is adjacent to the cathode, and the second opening is smaller than the fourth opening.

5. The reflex klystron of claim 4 , wherein the electron emission terminal extends into the fourth opening, and the first distance between the electron emission terminal and the sidewall is constant.

6. The reflex klystron of claim 1 , wherein the electron emitter structure is in a shape of peak, one of the plurality of electron emitters in a center of the electron emitter structure is the highest.

7. The reflex klystron of claim 6 , wherein a height of each of the plurality of electron emitters is gradually decreased along a direction away from the center.

8. The reflex klystron of claim 1 , wherein the electron emitter structure is a carbon nanotube array comprising a plurality of carbon nanotubes, a height of each of the plurality of carbon nanotubes is gradually decreased from a center of the carbon nanotube array.

9. The reflex klystron of claim 1 , wherein the first distance ranges from about 5 micrometers to about 100 micrometers.

10. The reflex klystron of claim 1 , further comprising an ion bombardment resistance material on each of the plurality of electron emitters.

11. The reflex klystron of claim 10 , wherein a material of the ion bombardment resistance material is selected from the group consisting of zirconium carbide, hafnium carbide, and lanthanum hexaboride.

12. The reflex klystron of claim 1 , wherein the electron emitter structure comprises a carbon nanotube wire comprising a plurality of carbon nanotube bundles, and each of the plurality of carbon nanotube bundle comprises a plurality of carbon nanotubes parallel with each other and extending toward the sidewall.

13. The reflex klystron of claim 12 , wherein one of the plurality of carbon nanotubes extends out of other of the plurality of carbon nanotubes.

14. The reflex klystron of claim 12 , wherein a maximum height of each of the plurality of carbon nanotube bundles is gradually decreased from a center of the electron emitter structure.

15. The reflex klystron of claim 1 , wherein the second grid is located between the first grid and the reflective electrode, and a third distance between the first grid and the second grid ranges from about 3 micrometers to about 25 micrometers.

16. The reflex klystron of claim 1 , further comprising a resistor layer sandwiched between the cathode and the electron emitter structure, and a resistance of the resistor layer is greater than 10 GΩ.

17. A reflex klystron, comprising:
a first substrate and a second substrate spaced from each other, wherein the first substrate and the second substrate are coupled together to form a resonant cavity;
a lens, wherein the lens is located on an end of the resonant cavity and configured as an output portion;
an electron emission device, wherein the electron emission device is configured to emit a plurality of electrons into the resonant cavity, the plurality of electrons are oscillated in the resonance cavity, and the electron emission device comprises:
an electron reflective structure on the second substrate, wherein the electron reflective structure comprises a reflective electrode and a second grid spaced from each other;
an electron emission structure on the first substrate, wherein the electron emission structure comprises a cathode, an electron extraction electrode, an electron emitter structure, and a first grid, the electron extraction electrode defines a through hole surrounded by a sidewall, the electron emitter structure comprises a conductor and a plurality of electron emitters on the conductor and extending toward the through hole, each of the plurality of electron emitters comprises an electron emission terminal, a distance between the electron emission terminal and the sidewall is constant, and a pressure in the electron emission device is smaller than or equal to 100 Pascal.

18. The reflex klystron of claim 17 , wherein a cross-section of the conductor is in a shape of triangle, the conductor comprises a first surface and a second surface facing to the sidewall, and the plurality of electron emitters are distributed on the first surface and the second surface.

19. The reflex klystron of claim 17 , wherein the conductor is in a shape of hemisphere, the conductor comprises a curved surface, and the plurality of electron emitters are distributed on the curved surface.

20. An electron emission device, comprising:
an anode;
a cathode spaced from the anode;
an electron emitter structure electrically connected to the cathode;
an electron extraction electrode insulated from the cathode via an insulating layer, wherein the electron extraction electrode defines a through hole surrounded by a sidewall, and the electron emitter structure faces to the sidewall;
wherein the electron emitter structure comprises a plurality of electron emitters extending toward the sidewall, each of the plurality of electron emitters comprises an electron emission terminal, a first distance between the electron emission terminal of each of the plurality of electron emitters and the sidewall is constant, a second distance between the electron emission terminal and the anode is greater than or equal to 10 micrometers and smaller than or equal to 200 micrometers, and a pressure in the electron emission device is smaller than or equal to 100 Pascal.

Assignees

• Univ Tsinghua
• Hon Hai Prec Ind Co Ltd

Inventors

• Liu Peng
• Chen Pi-Jin
• Zhou Duan-Liang
• Zhang chun-hai
• Fan Shou-Shan

Classifications

• H01J3/021

  Electron guns using a field emission, photo emission, or secondary emission electron source · CPC title

• H01J2201/30469

  Carbon nanotubes (CNTs) · CPC title

• H01J23/04

  Cathodes · CPC title

• H01J25/22 Primary

  Reflex klystrons, i.e. tubes having one or more resonators, with a single reflection of the electron stream, and in which the stream is modulated mainly by velocity in the modulator zone · CPC title

• H01J1/304

  Field-emissive cathodes · CPC title