Electron source and production method therefor

Patent metadata

Field	Value
Publication number	US-10957511-B2
Application number	US-201916707877-A
Country	US
Kind code	B2
Filing date	Dec 9, 2019
Priority date	Jul 19, 2016
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

An electron source capable of suppressing consumption of an electron emission material is provide. The present invention provides an electron source including: an electron emission material; and, an electron emission-suppressing material covering a side surface of the electron emission material, wherein a work function of the electron emission-suppressing material is higher than that of the electron emission material, and a thermal emissivity of the electron emission-suppressing material is lower than that of the electron emission material.

First claim

What is claimed is:

1. An electron source comprising:
an electron emission material; and,
an electron emission-suppressing material covering a side surface of the electron emission material,
wherein a work function of the electron emission-suppressing material is higher than that of the electron emission material, and
the side surface of the electron emission material has a (100) crystal plane at an outer peripheral portion thereof.

2. The electron source according to claim 1 , wherein the electron emission material comprises at least one selected from the group consisting of lanthanum boride, cerium boride and iridium cerium.

3. The electron source according to claim 1 , wherein the electron emission-suppressing material comprises at least one selected from the group consisting of metallic tantalum, metallic titanium, metallic zirconium, metallic tungsten, metallic molybdenum, metallic rhenium, tantalum carbide, titanium carbide and zirconium carbide.

4. The electron source according to claim 1 , wherein an end surface of the electron emission material is on the same plane as an end surface of the electron emission-suppressing material.

5. The electron source according to claim 4 , wherein a normal to the plane is in a direction of emission of electrons.

6. The electron source according to claim 1 , wherein shape of the electron emission-suppressing material is a thin film.

7. The electron source according to claim 6 , wherein the thin film has a thickness of 0.1 to 2 μm.

8. The electron source according to claim 1 , further comprising a support member around the electron emission-suppressing material.

9. The electron source according to claim 8 , wherein the support member is closely attached to the electron emission-suppressing material.

10. The electron source according to claim 8 , wherein the support member is made of graphite.

11. A method for manufacturing an electron source according to claim 1 , comprising an applying step and a solidifying step,
wherein, in the applying step, paste containing electron emission-suppressing material is applied to a side surface of an electron emission material, and
in the solidifying step, the paste is solidified.

12. The method according to claim 11 , further comprising an inserting step between the applying step and the solidifying step, wherein, in the inserting step, the electron emission material having the applied paste is inserted into an opening provided in a support member.

Assignees

• Denka Company Ltd

Inventors

• Morishita Toshiyuki
• Chatani Hiromitsu
• Hirokawa Shimpei
• Ibayashi Toshiyuki
• Sugimoto Isao

Classifications

• H01J1/148 Primary

  with compounds having metallic conductive properties, e.g. lanthanum boride, as an emissive material · CPC title

• H01J2237/06341

  Field emission · CPC title

• H01J2201/30426

  Coatings on the emitter surface, e.g. with low work function materials · CPC title

• H01J9/04

  of thermionic cathodes · CPC title

• H01J2209/012

  Coating · CPC title