Field emission device and field emission method

Patent metadata

Field	Value
Publication number	US-10651001-B2
Application number	US-201716312565-A
Country	US
Kind code	B2
Filing date	Mar 16, 2017
Priority date	Jun 24, 2016
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

An emitter ( 3 ) and a target ( 7 ) are arranged so as to face each other in a vacuum chamber ( 1 ), and a guard electrode ( 5 ) is provided at an outer circumferential side of an electron generating portion ( 31 ) of the emitter ( 3 ). The emitter ( 3 ) is supported movably in both end directions of the vacuum chamber ( 1 ) by the emitter supporting unit ( 4 ) having a movable body ( 40 ). The emitter supporting unit ( 4 ) is operated by an operating unit ( 6 ) connected to the emitter supporting unit ( 4 ). By operating the emitter supporting unit ( 4 ) by the operating unit ( 6 ), a distance between the electron generating portion ( 31 ) of the emitter ( 3 ) and the target ( 7 ) is changed, and a position of the emitter ( 3 ) is fixed at an arbitrary distance, then field emission is performed with the position of the emitter ( 3 ) fixed.

First claim

The invention claimed is:

1. An electric field radiation device comprising:
a vacuum enclosure formed by sealing a tubular insulator at a first end and a second end to form a vacuum chamber at an inner wall side of the insulator;
an emitter positioned at the first end of the vacuum chamber and having an electron generating portion disposed to face the second end of the vacuum chamber;
a guard electrode arranged at an outer circumferential side of the electron generating portion of the emitter;
a target positioned at the second end of the vacuum chamber and disposed to face to the electron generating portion of the emitter;
a movable emitter supporting unit configured to move the emitter in both end directions of the vacuum chamber; and
an operating unit connected to the emitter supporting unit and configured to operate the emitter supporting unit,
wherein the operating unit is configured to change a distance between the electron generating portion of the emitter and the target and fix a position of the emitter at an arbitrary distance by operation of the emitter supporting unit,
wherein the guard electrode comprises, at a target side thereof, a small diameter portion which the electron generating portion of the emitter contacts and separates from, and
the electron generating portion of the emitter performs field emission with the position of the emitter fixed.

2. The electric field radiation device as claimed in claim 1 , wherein:
the emitter supporting unit supports the emitter through a movable body that is movable, by the operating unit, in both end directions of the vacuum chamber,
the operating unit has an adjustment screw portion comprising a screw shaft screwed into and connected to a first side of the movable body so as to extend in a same direction as an axis of the movable body and rotatably retained by the first side of the movable body, and
the movable body moves in both end directions by turning of the adjustment screw portion by the operating unit, the distance between the electron generating portion of the emitter and the target is changed, and the position of the emitter is fixed at the arbitrary distance.

3. The electric field radiation device as claimed in claim 2 , wherein:
a motor for turning the adjustment screw portion is connected to the adjustment screw portion through an insulator.

4. The electric field radiation device as claimed in claim 2 , wherein:
the movable body has a shape that extends in both end directions of the vacuum chamber at an opposite side to the electron generating portion of the emitter.

5. The electric field radiation device as claimed in claim 1 , wherein:
the emitter supporting unit supports the emitter through a movable body that is movable, by the operating unit, in both end directions of the vacuum chamber,
the operating unit has a piston that can reciprocate along an axis of the movable body that is connected to a first side of the movable body, and
the movable body moves in both end directions by reciprocating motion of the piston by the operating unit, the distance between the electron generating portion of the emitter and the target is changed, and the position of the emitter is fixed at the arbitrary distance.

6. The electric field radiation device as claimed in claim 5 , wherein:
the piston is connected to the movable body through an insulator.

7. The electric field radiation device as claimed in claim 1 , wherein:
the guard electrode comprises, at a target side thereof, an edge portion that extends in a crossing direction of the vacuum chamber and overlaps with a circumferential edge portion of the electron generating portion of the emitter in both end directions of the vacuum chamber.

8. The electric field radiation device as claimed in claim 1 , further comprising:
bellows that can expand and contract in both end directions of the vacuum chamber, and wherein
a first side of the bellows is retained by the emitter supporting unit, and a second side of the bellows is retained by the vacuum enclosure.

9. The electric field radiation device as claimed in claim 1 , wherein:
a grid electrode is provided between the emitter and the target in the vacuum chamber.

10. A field emission method of the electric field radiation device as claimed in claim 1 , comprising:
setting an output of a field emission current by changing the distance between the electron generating portion of the emitter and the target and by fixing the position of the emitter at the arbitrary distance by operation of the operating unit; and
performing field emission from the electron generating portion of the emitter with the position of the emitter fixed.

11. The field emission method of the electric field radiation device as claimed in claim 10 , wherein:
the output of the field emission current is set without changing a tube voltage.

Assignees

• Meidensha Electric Mfg Co Ltd

Inventors

• Takahashi Daizo
• Hatanaka Michihiro

Classifications

• H01J2235/062

  Cold cathodes · CPC title

• H01J7/18

  Means for absorbing or adsorbing gas, e.g. by gettering · CPC title

• H01J1/3044 Primary

  Point emitters · CPC title

• H01J3/021

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

• H01J2201/30453

  Carbon types · CPC title