WO2015105260A1 - Générateur de rayons x ayant une structure anti-charge de dispositif émetteur d'électrons à triode - Google Patents

Générateur de rayons x ayant une structure anti-charge de dispositif émetteur d'électrons à triode Download PDF

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Publication number
WO2015105260A1
WO2015105260A1 PCT/KR2014/008991 KR2014008991W WO2015105260A1 WO 2015105260 A1 WO2015105260 A1 WO 2015105260A1 KR 2014008991 W KR2014008991 W KR 2014008991W WO 2015105260 A1 WO2015105260 A1 WO 2015105260A1
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WO
WIPO (PCT)
Prior art keywords
cathode
emitting device
anode
electron emitting
electron
Prior art date
Application number
PCT/KR2014/008991
Other languages
English (en)
Inventor
Dae-Jun Kim
Do-Yun Kim
Dong-Il Kim
Seung-Min YOU
Kwan-Soo Park
Seung-Wan SEO
Ji-Hye Park
Original Assignee
Vacuum Science & Instrument Co., Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Vacuum Science & Instrument Co., Ltd filed Critical Vacuum Science & Instrument Co., Ltd
Publication of WO2015105260A1 publication Critical patent/WO2015105260A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H01J35/045—Electrodes for controlling the current of the cathode ray, e.g. control grids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor
    • H01J35/06—Cathodes
    • H01J35/065—Field emission, photo emission or secondary emission cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/14—Arrangements for concentrating, focusing, or directing the cathode ray
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/30—Cold cathodes
    • H01J2201/304—Field emission cathodes
    • H01J2201/30446—Field emission cathodes characterised by the emitter material
    • H01J2201/30453—Carbon types
    • H01J2201/30469—Carbon nanotubes (CNTs)

Definitions

  • the present invention relates to an X-ray generator, and more particularly to a triode electron emitting structure capable of preventing electrical charge of insulator and a triode electron emitting device using the same.
  • the electron emitter using the cold cathode includes FEA (Field Emitter Array) type, SCE (Surface Conduction Emitter) type, MIM (Metal-Insulator-Metal) type or MIS (Metal-Insulator-Semiconductor) type and BSE (Ballisticel ectron Surface Emitter) type electron emitter.
  • FEA Field Emitter Array
  • SCE Surface Conduction Emitter
  • MIM Metal-Insulator-Metal
  • MIS Metal-Insulator-Semiconductor
  • BSE Billallisticel ectron Surface Emitter
  • the above electron emitters have different structure in detail, but generally include a structure for emitting electrons or electron emitting unit in a vacuum vessel and uses electrons emitted by the electron emitting unit. Additionally the above electron emitters include a fluorescent layer or an X-ray target material, which are disposed opposite to the electron emitting unit in the vacuum vessel, to show luminance operation or to generate X-ray.
  • the above electron emitters are embodied as a diode type with a cathode and an anode or a triode type with a cathode, an anode and a gate/grid, and an insulation layer with a specific thickness is formed between the electrodes.
  • electrons emitted by an electron source have a few eV of initial acceleration and speed (momentum) in case of the hot cathode type so that the trace of the electrons are adjusted only by electric field between the cathode and the anode.
  • electrons emitted by an electron source have a few keV of initial acceleration and speed (momentum) in case of the cold cathode type so that it is hard to adjust the trace of the electrons emitted in abnormal direction (or undesirable direction) even though a structure for inducing electron trace is included.
  • electrons emitted by a cathode of an electron emitter with normal electric field distribution are accumulated at an insulator for insulating each electrode before arriving at a target to deteriorate insulation between electrodes, to induce abnormal operation of the electron emitter, to destroy the electron emitter by arc discharge, and to induce malfunction of the electron emitter.
  • a spacer with metal pattern is used to discharge electron in order to prevent electric charging of a spacer used for the electron emitter, or high electric field is applied to a grid near the spacer to change trace of electron beam in order to prevent charging of the spacer.
  • the above solutions are only capable of preventing electric charging of the spacer but not capable of preventing electric charging of insulator between the cathode and gate/grid. Further, the above solutions are preventing for electric charging of the spacer so that it is hard to apply the above solutions to an electron emitter without the spacer. Furthermore, an additional electrode for preventing electrical charge of the spacer and an additional driving voltage are required to increase the number of components so that manufacturing cost is increased.
  • the present invention provides an electron emitter capable of preventing electrical charge of the insulator fundamentally by not exposing the insulator to electrons emitted by a cathode of the electron emitter and an electron trace.
  • the present invention for solving the above technical problem presents an electron emitting device with metal structure (subrack) having the same voltage as a cathode electrode, and the metal structure (subrack) supports and fastens an electrode structure having at least one bending portion, in electron emitting devices having an insulation substrate, cathode with electron source emitting electrons, electrode structure generating electric fields and a target part generating X-ray when receiving electrons.
  • An insulator is formed on the metal structure (subrack) supporing and fastening the electrode structure, and at least one of bending portion of the electrode structure bends toward the cathode.
  • An electron source emitting electrons comprises at least one of the group consisting of carbon nanotube, graphene, carbon, diamond liked carbon, fullerene and silicon nanowire.
  • An X-ray generator having an anti-charging structure of a triode electron emitting device includes: a cathode having an electron source emitting electrons; an anode disposed opposite to the cathode; a metal material formed at a center region of the anode to generate X-ray when the electrons are irradiated thereto; a carbon nanotube formed as a electron emitting device in a region of the cathode, which corresponds to a crossing of the cathode and the anode; a gate disposed between the cathode and the anode with spacing in order to control electrons emitted by the carbon nanotube; a pair of focusing electrodes bended to facilitate combination with both ends of the gate, respectively; subracks disposed between the cathode and the focusing electrodes, respectively, and connected to the cathode to have same electric potential as the cathode; and insulators disposed between the subracks and the focusing electrodes.
  • the pair of focusing electrodes extends toward the cathode electrode at a bending region.
  • the focusing electrode has a vertical portion and a horizontal portion with at least a ratio of about 1:1.5.
  • electron source emitting electrons comprises at least one of the group consisting of carbon nanotube, graphene, carbon, diamond liked carbon, fullerene and silicon nanowire.
  • the insulator near electron emitting device is prevented from being electrically charged through a structural characteristic of the metal structure and electrode structure to prevent problems induced by electric charging of the insulator by not disposing the insulator near the electron emitter by applying the metal structure near the electron emitting device in order not to expose the insulator to the electrons emitted by the electron emitting device and to the electron trance, and by not exposing the insulator for insulating the metal structure and the electrode structure of the cathode and the gate/grid, which is disposed on the metal structure, from each other to the electrons and the electron trace.
  • FIG. 1 is a schematic cross-sectional view showing an X-ray generator with a triode electron emitting device of anti-charging structure according to an embodiment of the present invention.
  • FIG. 2 is a schematic cross-sectional view showing an X-ray generator with a triode electron emitting device of anti-charging structure according to another embodiment of the present invention.
  • FIG. 3 is a perspective view showing main parts of an X-ray generator with a triode electron emitting device of anti-charging structure according to an embodiment of the present invention.
  • FIG. 4 is a cross-sectional view showing size and space of each components of an X-ray generator with a triode electron emitting device of anti-charging structure according to another embodiment of the present invention.
  • first, second, third etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, or section discussed below could be termed a second element, component, or section without departing from the teachings of the present invention.
  • FIG. 1 is a schematic cross-sectional view showing an electron emitter according to an embodiment of the present invention.
  • a cathode 21 with an electron emitting part 22 formed by CNT, etc. is formed on a substrate 20, and a metal structure (subrack) 23 connected onto the cathode 21 to be applied the same voltage with the cathode 21 is positioned.
  • a metal structure (subrack) 23 connected onto the cathode 21 to be applied the same voltage with the cathode 21 is positioned.
  • An electrode structure with a gate 25 and a grid 26 integrally formed with each other is disposed on the metal structure 23 to be supported and fixed by the metal structure 23.
  • the cathode 21 and the metal structure 23 are connected so that the same voltage is applied thereto, and a second voltage different from the cathode 21 is applied to the electrode structure 25 and 26.
  • An insulator 24 is disposed between the metal structure 23 and the electrode structure 25 and 26 to insulate them.
  • the metal structure 23 supports and fixes the electrode structure 25 and 26 disposed thereon and prevents the insulator from being electrically charged. As long as the metal structure 23 supports and fixes the electrode structure 25 and 26, the shape and form of the metal structure 23 are not specially limited.
  • the gate 25 and the grid 26 are integrally formed. A bending portion of the grid 26 is connected to the gate 25.
  • the metal structure 23, the insulator 24, the electrode structure 25 and 26 may be combined by a fastening means (not shown) such as a bolt, a clamp, etc., and a fastening method and the shape of the metal structure 23, which may be changed according to the fastening method, are not specially limited.
  • the cathode substrate 21, the metal structure 23, and insulator 24 and the electrode structure 25 and 26 are combined with each other to be one body, disposed in an outer case 20 and 21, and then an anode/target 27 is combined at the top portion of the outer case 20 and 21 to embody the electron emitter.
  • FIG. 2 is a figure showing another embodiment in which a bending portion and a position of an insulator are different.
  • the grid 26-1 in FIG. 1 extends upward so that focusing of electrons is enhanced to improve efficiency of the electron emitter through the extended portion 26-2 of the grid.
  • FIG. 3 is a perspective view showing main parts of an electron emitter according to an embodiment of the present invention.
  • a cathode substrate 31 is formed on an insulation substrate 30 such as glass, ceramic, etc., and a metal structure 33 having a rectangular frame shape with an opening for exposing electron emitting device is disposed on the cathode substrate 31.
  • An insulator 34 having a ring shape is disposed on the metal structure 33 along edges of the metal structure 33, and an electrode structure 36 with a gate 35 connected thereto is disposed on the insulator 34.
  • the electrode structure 36 has a bending portion, and the gate electrode 35 connected to an end portion of the bending portion is disposed in the opening of the metal structure 33, and the electrode structure 36 has a shoulder making contact with the insulator and edges of the metal structure 33.
  • the gate electrode 35 is spaced apart from the electron emitting device, and the gate electrode 35 is integrally formed to compose the electrode structure 36.
  • a bending surface 26-1 of the electrode structure 36 operates as a grid for focusing electron beams, and focuses electron beam emitted by the electron emitting part 22 to a target.
  • the metal structure 33 connected to the cathode 31, the insulator 34 and the electrode structure 36 may be combined through a plurality of clamps to be one body, but the fastening method is not only limited to the clamp fastening but various method such as bolt fastening may be used.
  • FIG. 4 shows size and space of each components of an X-ray generator of the present invention.
  • a space‘a’ is a space between the target (anode) and a grid, and the space‘a’ is not specially limited. But, the target does not make contact with the grid.
  • a space‘b’ is a height of a bending portion of the electrode structure.
  • the space‘b’ is in a range in which the electron emitting device and the anode electrode do not make contact with each other, and at least 2mm to improve focusing efficiency of electron beam.
  • a space‘c’ is a space between the bending portion and the metal structure.
  • the space‘c’ may be in a range of 10 ⁇ m ⁇ 3mm, and more preferably in a range of 200 ⁇ m ⁇ 1mm.
  • a space‘d’ is a width of a horizontal surface ( a surface parallel to the anode) of the electrode structure.
  • the space‘d’ may be equal to or greater than 3mm, and may be enlarged to outer case surface in maximum.
  • the ratio of the space‘b’ and the space‘d’ may be about 1:1.5 to effectively supporting and fastening of the electrode structure, but the ratio is not limited to that.
  • the triode electron emitting device in which the insulator is not exposed to prevent electrical charge of the insulator and to improve electron beam focusing and the X-ray generator having the same can be manufactured.

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  • Cold Cathode And The Manufacture (AREA)

Abstract

L'invention concerne une structure innovante de dispositif émetteur d'électrons, qui est capable de prévenir la charge électrique d'un isolant, et un générateur de rayons X qui utilise cette structure. La présente invention comprend : une cathode possédant une source d'électrons émettant des électrons ; une anode disposée à l'opposé de la cathode ; un matériau métallique formé en une région centrale de l'anode pour produire des rayons X lorsque les électrons sont projetés dessus ; un nanotube de carbone formé comme dispositif émetteur d'électrons dans une région de la cathode qui correspond à un croisement de la cathode et de l'anode ; une porte disposée entre la cathode et l'anode avec un espacement permettant de contrôler les électrons émis par le nanotube de carbone ; une paire d'électrodes de focalisation courbées pour faciliter la combinaison avec les deux extrémités de la porte, respectivement ; des coffrets disposés entre la cathode et les électrodes de focalisation, respectivement, et reliés à la cathode pour avoir le même potentiel électrique que la cathode ; et des isolants disposés entre les coffrets et les électrodes de focalisation. Avec le dispositif émetteur d'électrons à triode doté de la structure ci-dessus, l'isolant n'est pas exposé à un émetteur d'électrons, ce qui résout les problèmes tels que les arcs électriques et les destructions de dispositifs, etc. Il est par conséquent possible de fabriquer un générateur de rayons X produisant des rayons X de manière stable.
PCT/KR2014/008991 2014-01-13 2014-09-26 Générateur de rayons x ayant une structure anti-charge de dispositif émetteur d'électrons à triode WO2015105260A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR10-2014-0004224 2014-01-13
KR1020140004224A KR20150084324A (ko) 2014-01-13 2014-01-13 안티차징 구조의 3극 전계방출소자를 구비한 x-선관

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105470078A (zh) * 2015-12-29 2016-04-06 无锡吉仓纳米材料科技有限公司 基于碳纳米管冷阴极的聚焦型三极结构全封装x射线球管
JP2017183028A (ja) * 2016-03-30 2017-10-05 キヤノン株式会社 電子銃を備えたｘ線発生管及びｘ線撮影装置
CN111081505A (zh) * 2019-12-24 2020-04-28 中山大学 一种共面双栅聚焦结构的纳米冷阴极电子源及其制作方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001351507A (ja) * 1991-05-13 2001-12-21 Seiko Epson Corp 電界電子放出装置及びその製造方法
KR20070028000A (ko) * 2005-08-30 2007-03-12 삼성에스디아이 주식회사 전자 방출 디바이스 및 이를 이용한 전자 방출 표시디바이스
KR20070043392A (ko) * 2005-10-21 2007-04-25 삼성에스디아이 주식회사 전자 방출 디바이스, 이를 이용한 전자 방출 표시 디바이스및 이의 제조 방법
KR20120114585A (ko) * 2011-04-07 2012-10-17 삼성전자주식회사 전자빔 발생 장치 및 이를 포함하는 Ｘ-ｒａｙ 발생 장치

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001351507A (ja) * 1991-05-13 2001-12-21 Seiko Epson Corp 電界電子放出装置及びその製造方法
KR20070028000A (ko) * 2005-08-30 2007-03-12 삼성에스디아이 주식회사 전자 방출 디바이스 및 이를 이용한 전자 방출 표시디바이스
KR20070043392A (ko) * 2005-10-21 2007-04-25 삼성에스디아이 주식회사 전자 방출 디바이스, 이를 이용한 전자 방출 표시 디바이스및 이의 제조 방법
KR20120114585A (ko) * 2011-04-07 2012-10-17 삼성전자주식회사 전자빔 발생 장치 및 이를 포함하는 Ｘ-ｒａｙ 발생 장치

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105470078A (zh) * 2015-12-29 2016-04-06 无锡吉仓纳米材料科技有限公司 基于碳纳米管冷阴极的聚焦型三极结构全封装x射线球管
JP2017183028A (ja) * 2016-03-30 2017-10-05 キヤノン株式会社 電子銃を備えたｘ線発生管及びｘ線撮影装置
CN111081505A (zh) * 2019-12-24 2020-04-28 中山大学 一种共面双栅聚焦结构的纳米冷阴极电子源及其制作方法

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