KR20230164253A - X-ray source and manufacturing method thereof - Google Patents

Abstract

The X-ray tube according to the present invention includes a tube body made of an insulating material and having a predetermined space therein; An anode electrode disposed on one end of the tube body and coupled with a target; a cathode electrode disposed at the other end of the tube body to face the anode electrode; a field emitter portion including at least two emitter regions located on top of the cathode electrode; and a control unit that independently controls electron emission in each emitter region through a gate voltage.

Description

X-ray tube and method of manufacturing the same {X-RAY SOURCE AND MANUFACTURING METHOD THEREOF}

The present invention relates to an X-ray tube and a method of manufacturing the same.

A typical X-ray generator consists of a cathode (cathode) that generates an electron beam and an anode (anode) that generates X-rays when the electron beam from the cathode collides with high kinetic energy. In other words, the output of the X-ray generator is proportional to the current of the electron beam coming from the cathode (tube current) and the voltage applied between the cathode and anode (tube voltage).

At this time, a target made of a metal material with a high atomic number such as tungsten, molybdenum, or copper is formed at the anode, and electrons that hit the target undergo acceleration due to electromagnetic interaction with the target atoms and emit X-ray radiation. Alternatively, X-rays are produced by emitting electromagnetic radiation corresponding to the energy difference between the excited state and the ground state when the electrons bound to the target atom are excited by exchanging momentum and energy with the electrons hitting the target and then return to the ground state. Create.

In general, X-ray tubes go through an aging process that increases the anode temperature by emitting electron beams to the anode during pumping to improve the internal vacuum and reduce outgassing from the anode target during operation. At this time, the emitter emits electrons under harsher conditions than the environment normally used in order to generate sufficient heat in the anode. In this process, a problem arises in that the lifespan of the emitter is reduced.

Figure 1 is a perspective view showing a cathode electrode on which a conventional FEA chip is placed.

In this regard, as shown in FIG. 1, the field emitter arrays (FEA) chip 200a disposed on top of the existing cathode electrode 110 is located at the center circular portion and the corner of the FEA chip 200a. Each circular gate electrode is electrically connected to the electrode terminal, and the central circular part is integrated. Therefore, no matter which gate electrode located at the corner of the FEA chip 200a is applied, electron emission occurs in the circular part of the same area, and damage to the emitter may occur when the gate voltage for aging is applied.

In other words, the existing field emission type electron emission source has various advantages compared to the filament thermionic type electron emission source, but has the disadvantage of short lifespan. In addition, there is a problem that the actual usable life is shorter due to the life consumed during the aging process.

Additionally, in the case of existing emitter classification technology, the purpose is to increase power by expanding the electron emission area. In this case, the electron beam path and target focus change due to changes in the emission area, which has the disadvantage of complicating the structure.

Republic of Korea Patent No. 10-2095268 (Title of invention: Field emission X-ray source device)

The present invention is intended to solve the above-mentioned problem, and selectively uses an electron emission source to be used during aging and an electron emission source for actual use through an emitter region divided into at least two or more, and the electron emission source used for actual electron emission is selectively used. The technical task is to provide an X-ray tube with an extended emitter life.

The technical problems to be achieved by the present invention are not limited to the above-described technical problems, and other technical problems of the present invention can be derived from the following description.

As a technical means for solving the above-described technical problem, the X-ray tube according to the first aspect of the present invention includes a tube body made of an insulating material and having a predetermined space therein; An anode electrode disposed on one end of the tube body and coupled with a target; a cathode electrode disposed at the other end of the tube body to face the anode electrode; a field emitter portion including at least two emitter regions located on top of the cathode electrode; and a control unit that independently controls electron emission in each emitter region through a gate voltage.

The method of manufacturing an A step in which an It includes performing an aging process of applying a gate voltage to one of the emitter regions and applying an electron beam to the anode electrode.

According to the present invention, when an emitter for aging is used separately through an emitter area divided into at least two or more, there is an advantage in providing an can be greatly improved.

The effects of the present invention are not limited to the effects described above, and include all effects understood from the following description.

Figure 1 is a perspective view showing a cathode electrode on which a conventional FEA chip is placed.
Figure 2 is a schematic configuration diagram of an X-ray tube according to an embodiment of the present invention.
Figure 3 is a cross-sectional view of an X-ray tube according to an embodiment of the present invention.
Figure 4 is an enlarged plan view of the field emitter unit according to an embodiment of the present invention.
Figure 5 is an enlarged cross-sectional view of a portion of the field emitter unit according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating various arrangements of the first emitter area and the second emitter area according to an embodiment of the present invention.
Figure 7 is a flowchart for explaining a method of manufacturing an X-ray tube according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the attached drawings. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In addition, the attached drawings are only intended to facilitate understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the attached drawings. In order to clearly explain the present invention in the drawings, parts not related to the description are omitted, and the size, shape, and shape of each component shown in the drawings may be modified in various ways. Throughout the specification, identical/similar parts are given identical/similar reference numerals.

The suffixes “module” and “part” for components used in the following description are given or used interchangeably only for the ease of preparing the specification, and do not have distinct meanings or roles in themselves. Additionally, in describing the embodiments disclosed in this specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed descriptions are omitted.

Throughout the specification, when a part is said to be “connected (connected, contacted, or combined)” with another part, this means not only when it is “directly connected (connected, contacted, or combined),” but also when it has other members in between. It also includes cases where they are “indirectly connected (connected, contacted, or combined).” Additionally, when a part is said to "include (equip or provide)" a certain component, this does not exclude other components, unless specifically stated to the contrary, but rather "includes (provides or provides)" other components. It means you can.

Terms representing ordinal numbers, such as first, second, etc., used in this specification are used only for the purpose of distinguishing one component from another component and do not limit the order or relationship of the components. For example, the first component of the present invention may be named a second component, and similarly, the second component may also be named a first component.

Figure 2 is a schematic configuration diagram of an X-ray tube according to an embodiment of the present invention, and Figure 3 is a cross-sectional view of an X-ray tube according to an embodiment of the present invention.

Referring to Figures 2 and 3, the 160).

Illustratively, referring to Figure 2, the A field including an anode electrode 120, a cathode electrode 110 disposed at the other end of the tube body 10 to face the anode electrode 120, and at least two emitter regions located on top of the cathode electrode 110. It includes an emitter unit 200 and a control unit 130 that independently controls electron emission from each emitter region through a gate voltage.

Therefore, in the present invention, since each emitter region of the field emitter unit 200 is electrically independent, electrons can be emitted only from the emitter region to which the gate voltage is applied through the control unit 130. That is, an emitter may be used selectively, an emitter used for aging may be used only for the aging process, and an emitter actually used for emitting x-rays after completion of manufacturing of the x-ray tube may be used in a new state.

Specifically, referring to FIG. 3, the tube body 10 is formed in a cylindrical shape made of an insulating material, and has an exhaust pipe terminal 160 to create a vacuum state inside and a sealing member formed through which at least one electrode terminal 150 penetrates. may include.

The upper portion of the cathode electrode 110 includes a field emitter portion 200 including at least two emitter regions. Additionally, the cathode electrode 110 and the field emitter unit 200 may be commonly connected through one electrode terminal.

FIG. 4 is an enlarged plan view of a field emitter unit according to an embodiment of the present invention, and FIG. 5 is an enlarged cross-sectional view of a portion of the field emitter unit according to an embodiment of the present invention.

Referring to FIGS. 4 and 5 , the field emitter unit 200 includes a substrate 210, an insulating unit 220, a gate electrode unit 230, and a first emitter region 240a consisting of a plurality of emitters 241. and a second emitter area 240b.

Specifically, the field emitter unit 200 includes a plurality of emitters 241 formed on a substrate 210, a gate hole 231 through which electrons emitted from the emitters 241 pass, and a first emitter. The gate electrode portion 230 is divided into a region 240a and a second emitter region 240b, and is disposed between the substrate 210 and the gate electrode portion 230, and the first emitter portion of the gate electrode portion 230 It includes an insulating portion 220 formed to insulate the emitter region 240a and the second emitter region 240b from each other.

For example, the substrate 210 may be made of a Si-based semiconductor, but is not limited thereto. The emitter 241 may be composed of field emitter arrays (FEA), but is not limited thereto. Additionally, the emitter 241 is an electrode that controls the trajectory of emitted electrons, and may include a conductive material made of metal or carbon-based materials such as carbon nanotubes (CNTs), which are nanomaterials.

As shown in FIG. 4 , the gate electrode unit 230 may be formed with each divided region corresponding to the first emitter region 240a and the second emitter region 240b using each gate metal plate. For example, the gate electrode unit 230 may include each gate metal plate formed in a semicircular shape, and may be formed to have a separation distance D between each gate metal plate.

That is, the insulation of the insulating portion 220 that insulates the gate metal plate of the first emitter region 240a and the gate metal plate of the second emitter region 240b from each other through the spacing D of the gate electrode portion 230. A section can be secured. At this time, the insulating section of the insulating portion 220 may be exposed upwardly by the spacing D of the gate electrode portion 230.

The gate electrode unit 230 is electrically connected to the first electrode 230a, which is electrically connected to the gate metal plate of the first emitter region 240a through electrode wiring, and to the gate metal plate of the second emitter region 240b through electrode wiring. It includes a second electrode 230b connected to .

As shown in FIG. 5 , the insulating portion 220 includes a plurality of openings where emitters 241 are formed in portions corresponding to the first emitter region 240a and the second emitter region 240b. In addition, an insulating section D of a predetermined distance is included in a portion separating the first emitter region 240a of the insulating portion 220 and the second emitter region 240b of the insulating portion 220. Preferably, the insulating section D of the insulating portion 220 may be 3 um, but is not limited thereto.

Additionally, a plurality of openings may be formed in the insulating portion 220 except for the insulating section D through a patterning mask and an etching process while the insulating film is stacked on the substrate 210. That is, the insulating section D of the insulating film is not etched.

The control unit 130 applies a gate voltage for aging to one of the first emitter region 240a and the second emitter region 240b, and causes an electron beam to be emitted through this to cause aging of the anode electrode 120. Carry out the process. At this time, the gate voltage is not applied to the remaining emitter area.

After the aging process is completed, the control unit 130 sets the gate voltage to be applied to the remaining emitter area. In this way, the control unit 130 can independently control electron emission from each emitter region by adjusting the gate voltage application to the first emitter region 240a and the second emitter region 240b.

Illustratively, in the method of utilizing the control unit 130 according to the present invention, after completing the assembly and sealing process of the tube body 10, an aging process is performed to improve the internal vacuum and reduce outgassing at the anode target. . At this time, the control unit 130 may apply a voltage for the aging process to the gate electrode unit 230 of the first emitter region 240a and control electrons to be emitted only from the aging emitter. After the predetermined aging process is completed, during actual use of the X-ray tube for can be controlled to be emitted. The method of utilizing the control unit 130 described above can be utilized as an example of the method of manufacturing an X-ray tube, which will be described later with reference to FIG. 7 .

That is, the control unit 130 coupled to the

At this time, in the case of the first emitter region 240a or the second emitter region 240b of the present invention, it is simply used as an emitter for aging only for the purpose of allowing the emitted electrons to reach the target and increase the heat of the target. do. Therefore, the optical design required in existing emitter classification technology is not important, and the structure is simple compared to existing technology.

FIG. 6 is a diagram illustrating various arrangements of the first emitter area and the second emitter area according to an embodiment of the present invention.

As shown in FIGS. 6(a) and 6(b), the field emitter unit 200 may be formed in a shape where the first emitter area 240a surrounds the second emitter area 240b. The shape of each emitter area may be circular or square, but is not limited to this and may be polygonal. At this time, the separation space between the first emitter region 240a and the second emitter region 240b is not shown in FIGS. 6(a) and 6(b), but each emitter region remains insulated. You can.

Additionally, as shown in FIG. 6(c), the first emitter region 240a is arranged to surround the second emitter region 240b, but may be formed divided into a plurality of regions rather than as a single region. For example, the shape of each emitter area is shown as a circle, but it is not limited to this and may also be formed as a square or polygon. Additionally, as shown in FIG. 6(d), the first emitter area 240a and the second emitter area 240b may be arranged to be parallel with a space apart. At this time, the shape of each emitter area is shown as a rectangle, but is not limited to this and may be formed as a semicircle or polygon. Accordingly, the present invention has the advantage of being able to form various focal points of desired shapes because the emitter for actual use and the emitter for aging can be freely manufactured as needed.

That is, the present invention can be manufactured so that each emitter emission area of a field emission emitter with a Spindt structure manufactured using a semiconductor patterning process can be independently controlled. Through this, it is possible to separate the electron emission source for use during aging and the electron emission source for actual use in the X-ray tube manufacturing process.

In another embodiment, the tube body 10 may further include a focusing lens 140 on top of the cathode electrode 110 that focuses the electron beam emitted from the emitter 241 to the anode electrode 120. .

For example, the focusing lens 140 may be manufactured using a general hole shape, or may be manufactured by transferring one or multiple layers of graphene onto the lens. Additionally, two or more focusing lenses 140 may be used.

The anode electrode 120 may be formed of a metal with high electrical conductivity and thermal conductivity. For example, the anode electrode 120 may be formed of a combination of oxygen-free copper and KOVAR alloy, and KOVAR may be made of an iron-nickel-cobalt alloy. KOVAR alloy is prepared to have a thermal expansion coefficient similar to that of ceramic, which is advantageous for forming a bond with an insulator made of ceramic, and oxygen-free copper absorbs heat generated from the target 125 due to its high electrical and thermal conductivity. It is advantageous for release.

Additionally, a target 125 may be formed at the electron beam impact area of the anode electrode 120 to be bonded to the anode electrode 120.

The target 125 may be made of a material such as tungsten, which has a high melting point and high atomic number, so that it can generate X-rays with high efficiency when an electron beam collides with it. For example, the target 125 may be formed as a transmissive or reflective type.

For example, in the case of a reflective type, a window, which is an entrance/exit of X-rays emitted from the inside of the tube body 10 to the outside, may be formed in one area of the tube body 10. For example, the window may be made of a metal material such as beryllium or aluminum, or a glass material coated with a fluorescent material. If the window is made of a metal material such as beryllium, it may be filtered to emit only X-rays of a predetermined wavelength or less. Additionally, if the window is made of a glass material coated with a fluorescent material, visible light may be emitted through the window.

Meanwhile, the anode electrode 120 may be formed as a rotating electrode. Specifically, the anode electrode 120 may be composed of a target 125 provided on a rotating electrode, a rotor (not shown) supporting the target, and a rotation shaft (not shown). Accordingly, as the target 125 rotates when X-rays are generated, the electron beam collision area is formed into a circular track, thereby generating high output X-rays.

Exemplarily, referring again to FIG. 3 , the electrode terminal 150 supports the cathode electrode 110 and may be electrically connected to the cathode electrode 110 . Additionally, the electrode terminal 150 supports the focusing lens 140 and may be electrically connected to maintain a certain distance between the area to be exposed by the hole of the focusing lens 140 and the cathode electrode 110.

The exhaust pipe terminal 160 can be connected to a vacuum pump to exhaust the inside of the tube body 10. The exhaust pipe terminal 160 is formed of a material such as oxygen-free copper, and after exhaustion is completed, the exhaust pipe terminal 160 is sealed using a pinch-off method or the like so that the vacuum in the X-ray tube can be permanently preserved. Additionally, the exhaust pipe terminal 160 is electrically connected to the sealing member of the tube body 10 and can be used as an electrode with high current capacity.

Additionally, a metal thin film may be laminated on all surfaces of the upper surface of the sealing member except for the area where the electrode terminal 150 penetrates. At this time, when the metal thin film is electrically connected to the exhaust pipe terminal 160, it is not charged and can maintain a constant potential even if the photoelectric effect or Compton scattering due to X-ray emission occurs.

Hereinafter, descriptions will be omitted for components that perform the same function among the components shown in FIGS. 1 to 6 described above.

Figure 7 is a flowchart for explaining a method of manufacturing an X-ray tube according to another embodiment of the present invention.

Referring to FIG. 7, the method of manufacturing an 120), a cathode electrode 110 disposed at the other end of the tube body 10 to face the anode electrode 120, and a field emitter portion 200 including at least two emitter regions located on top of the cathode electrode 110. ) and a step (S110) in which an It includes performing an aging process of applying a voltage and applying an electron beam to the anode electrode 120 (S120).

In addition, the method of manufacturing the

Those of ordinary skill in the technical field to which the present invention pertains will be able to understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention based on the above description. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the patent claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

The scope of the present application is indicated by the claims described below rather than the detailed description above, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present application.

10: Tube body
110: cathode electrode
120: anode electrode
130: control unit
200: Field emitter section
210: substrate
220: insulation part
230: Gate electrode portion
240a: first emitter area
240b: second emitter area

Claims (10)

In the x-ray tube,
A tube body made of an insulating material and having a predetermined space therein;
an anode electrode disposed on one end of the tube body and coupled with a target;
a cathode electrode disposed at the other end of the tube body to face the anode electrode;
a field emitter portion including at least two emitter regions located on an upper portion of the cathode electrode; and
An X-ray tube including a control unit that independently controls electron emission in each emitter region through a gate voltage.
According to paragraph 1,
The field emitter unit is
A plurality of emitters formed on a substrate;
a gate electrode portion including a gate hole through which electrons emitted from the emitter pass, and divided into a first emitter region and a second emitter region; and
An X-ray tube disposed between the substrate and the gate electrode portion and including an insulating portion formed to insulate the first emitter region and the second emitter region of the gate electrode portion from each other.
According to paragraph 2,
The gate electrode part
Each divided region corresponding to the first emitter region and the second emitter region is formed of each gate metal plate,
An x-ray tube, comprising a spacing between each gate metal plate.
According to paragraph 3,
The gate electrode part
An X-ray tube comprising a first electrode and a second electrode electrically connected to each of the gate metal plates through electrode wiring.
According to paragraph 2,
The insulating part
It includes a plurality of openings through which the emitter is disposed in portions corresponding to the first emitter region and the second emitter region,
An X-ray tube comprising an insulating section of a predetermined distance in a portion separating the first emitter region and the second emitter region.
According to clause 5,
The insulating part
An X-ray tube in which the plurality of openings are formed in portions excluding the insulating section through a patterning mask and an etching process while an insulating film is laminated on the substrate.
According to paragraph 1,
The cathode electrode and the field emitter unit are commonly connected through one electrode terminal.
According to paragraph 2,
The control unit
An X-ray tube, wherein a gate voltage for aging is applied to one of the first emitter region and the second emitter region, and a gate voltage for X-ray irradiation is applied to the other one.
In the method of manufacturing an x-ray tube,
A tube body with a predetermined space formed inside, an anode electrode disposed on one end of the tube body and coupled with a target, a cathode electrode disposed on the other end of the tube body to face the anode electrode, and on top of the cathode electrode. A step of providing an
A method of manufacturing an
According to clause 9,
A method of manufacturing an

Images