KR102047436B1 - X-ray source unit and x-ray apparatus - Google Patents

Abstract

X-ray apparatus according to the present invention, the hollow body unit having a space therein, is provided in the interior of the body unit, the X-ray source unit for emitting electrons and coupled to the body unit to face the X-ray source unit, collision with the electrons And an anode unit for generating X-rays or light to guide the outside of the body unit, wherein the X-ray source unit includes at least one source unit for inserting at least one source unit and at least one source unit for generating electrons; At least one installation groove having a corresponding shape is provided, and includes a focusing unit for focusing and emitting electrons generated from the source unit to the outside. According to this configuration, the source portion can be easily aligned, and the electron emission efficiency due to the dual electric field can be improved.

Description

X-ray source unit and X-ray apparatus having same {X-RAY SOURCE UNIT AND X-RAY APPARATUS}

The present invention relates to an x-ray source unit and an x-ray apparatus having the same, and more specifically, to easily align the x-ray source unit due to the shape of the focusing unit for focusing electrons, and to enable dual electric fields to improve the x-ray generation efficiency. An x-ray source unit and an x-ray apparatus having the same.

In general, an X-ray tube is a vacuum tube for generating X-rays. The cathode of this X-ray tube is formed of tungsten filament and is heated by electric current to emit thermal electrons. In contrast, when a high voltage of tens of thousands of volts or more is applied to the anode of the X-ray tube, the electron flow emitted from the cathode moves toward the anode at high speed. At this time, when the electrons collide with the counter electrode made of tungsten, molybdenum or the like of the anode, energy is released as X-rays.

The observation of human tissues using radiological approach has greatly benefited the human civilization with its non-invasive advantages. In addition, due to the biotechnological and medical line of radiological approaches, observation of tissues ranging from a few millimeters to several micrometers has contributed greatly to many research and development activities and to improving human health.

However, the conventional radiation device having a resolution of the micrometer size has a limitation that it is difficult to observe the microstructure due to the lack of spatial resolution, so it must be observed using a huge radiation using the particle accelerator. In addition, the conventional micro-X-ray apparatus uses a filament-based electron emission source, there is a limitation in the application to various imaging devices due to the lack of emission x-ray flux (flux).

Accordingly, in recent years, various researches capable of photographing high quality X-rays have been continuously conducted.

Domestic Patent No. 10-1341672 (Registration Date: 2013.12.09) Domestic Patent No. 10-1701047 (Registration Date: 2017,01.23)

An object of the present invention is to provide an X-ray source unit that is easy to align and capable of dual electric fields.

Another object of the present invention is to provide an x-ray apparatus having an x-ray source unit that the above object is achieved.

X-ray source unit according to the present invention for achieving the above object, at least one source portion for generating electrons and at least one having a shape corresponding to each of the at least one source portion so that the at least one source portion is inserted and aligned, respectively One installation groove is provided, and includes a focusing unit for focusing the electrons generated from the at least one source unit to the outside.

According to one side, the at least one source unit may generate the electrons in at least one of the filament-based hot electron emission method and carbon nanotube (CNT) based field emission method.

According to one side, the at least one source unit is provided with a plurality of filament-based hot electron emission method and carbon nanotube (CNT) -based field emission method at least one of the plurality, respectively, the focusing unit is provided The installation groove may have a cup shape provided in plurality on an upper surface to correspond to the number of source portions.

According to one side, the source portion includes a first and second source portion for generating the electrons in at least one of the filament-based hot electron emission method and carbon nanotube (CNT) -based field emission method, respectively, the focusing The portion has a cup shape, and has a shape corresponding to the first and second source portions and a focusing body provided with first and second inclined surfaces facing each other in a V-shape to face each other. Each of the two inclined surfaces may include first and second installation grooves in which the first and second source portions are inserted and aligned.

According to one side, the at least one installation groove may be formed through the line hole through which the electrode line of the source portion passes.

According to one side, the at least one source unit, a negative electrode for applying an electrode of the cathode, an emitter stacked on the negative electrode to emit electrons, an emitter cover stacked on the emitter to prevent the edge effect, the emitter cover A patterning electrode for patterning the electrons stacked and emitted on the substrate; a first insulator stacked between the emitter and the emitter cover and insulated from each other; a second insulator stacked between the emitter cover and the patterning electrode and insulated from each other; It may include a first support for supporting the bottom surface of the negative electrode, and a second support stacked on top of the second insulator, the opening through which the electrons are emitted.

According to one side, the negative electrode and the patterning electrode may have a mesh (mesh) shape.

According to one side, the negative electrode line extending from the negative electrode is connected to the interior of the focusing portion through the first support, the patterning electrode line extending from the patterning electrode is the second insulator, emitter cover, the first insulator and It may be connected to the inside of the focusing portion through the first support.

According to one side, the at least one mounting groove of the focusing unit may be formed through the electrode hole through which the negative electrode line and the patterning electrode line pass.

X-ray apparatus according to an embodiment of the present invention, the hollow body unit having a space therein, provided in the body unit, the X-ray source unit for emitting electrons and the X-ray source unit to face the body unit And an anode unit coupled to generate the X-rays or light by collision with the electrons and to guide the outside of the body unit, wherein the X-ray source unit includes at least one source unit and the at least one source generating the electrons; At least one installation groove having a shape corresponding to the at least one source portion is provided so that the source portion of the source portion can be inserted, and includes a focusing portion for focusing and emitting electrons generated from the source portion to the outside.

According to one side, the at least one source portion includes a first and second source portion for generating the electrons in at least one of the filament-based hot electron emission method and carbon nanotube (CNT) based field emission method, The at least one installation groove may include first and second installation grooves into which the first and second source portions are respectively inserted.

According to one side, the focusing portion has a cup shape, the first surface and the second inclined surface is connected to the V-shape on the upper surface, the first and second installation grooves are to be formed on the first and second slope, respectively Can be.

According to one side, the first and second installation grooves may be formed through the first and second line holes through which the electrode line of the first and second source portion can pass.

According to one side, the at least one source unit, a negative electrode for applying an electrode of the cathode, an emitter stacked on the negative electrode to emit electrons, an emitter cover stacked on the emitter to prevent the edge effect, the emitter cover A patterning electrode for patterning the electrons stacked and emitted on the substrate; a first insulator stacked between the emitter and the emitter cover and insulated from each other; a second insulator stacked between the emitter cover and the patterning electrode and insulated from each other; It may include a first support for supporting the bottom surface of the negative electrode, and a second support stacked on top of the second insulator, the opening through which the electrons are emitted.

According to one side, the negative electrode line extending from the negative electrode is connected to the interior of the focusing portion through the first support, the patterning electrode line extending from the patterning electrode is the second insulator, emitter cover, the first insulator and It may be connected to the inside of the focusing portion through the first support.

According to the present invention having the configuration as described above, first, the source portion is inserted into the installation groove provided in the focusing portion, it is easy to align even in a simple process it is possible to improve the safety.

Second, a plurality of inclined surfaces are formed on the upper surface of the cup-shaped focusing portion, and a plurality of source portions are aligned and inserted with respect to the plurality of inclined surfaces, thereby enabling a plurality of electron emission.

Third, X-ray emission for a variety of conditions due to the plurality of source parts that can generate electrons in at least one of the field emission method using hot electrons or nanocarbon tube (CNT) growth obtained by heating the filament as needed The efficiency can be improved.

1 is a perspective view schematically showing the x-ray apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view schematically showing the x-ray source unit shown in FIG. 1.
3 is an exploded perspective view schematically illustrating an exploded x-ray source unit shown in FIG. 2.
4 is a plan view schematically illustrating a focusing unit of the X-ray source unit illustrated in FIG. 2. And,
FIG. 5 is a rear view schematically illustrating the focusing unit illustrated in FIG. 4.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a perspective view schematically showing an x-ray apparatus 1 according to a preferred embodiment of the present invention, and FIG. 2 is a perspective view schematically showing an x-ray source unit 20 of the x-ray apparatus 1.

Referring to FIG. 1, the x-ray apparatus 1 according to an exemplary embodiment of the present invention includes a body unit 10, an x-ray source unit 20, and an anode unit 30.

For reference, the X-ray apparatus 1 described in the present invention is illustrated and illustrated as an X-ray apparatus for generating an X-ray for a medical device, but is not limited thereto. That is, it is obvious that the X-ray apparatus 1 according to the present invention may be applied to various light source fields for generating light energy.

The body unit 10 is provided in a hollow to have a space therein, and supports the source unit 20 and the anode unit 30 to be described later. The body unit 10 has a cylindrical shape including a bottom portion 11 supporting the source unit 20 and a side portion 12 extending vertically upward from the bottom portion 11. Here, the bottom portion 11 and the side portion 12 is formed of a non-metallic, that is, an insulating material such as ceramic and glass, it is preferable to prevent electrical interference with electrons generated from the X-ray source unit 20 to be described later.

For reference, although not shown in detail, the side portion 12 of the body unit 10 may be provided with a window (not shown) which is an entrance and exit of X-rays emitted from the inside of the body unit 10 to the outside. In this case, the window (not shown) may be formed of a metallic material such as beryllium, aluminum, or a glass material coated with a fluorescent material. If the window (not shown) is formed of a metal material such as beryllium, it may be filtered to emit only X-rays of a predetermined wavelength or less, and if the window (not shown) is formed of a glass material coated with a fluorescent material, Visible light may be emitted through the window (not shown). However, it may be provided without a window (not shown) according to the purpose of use of the x-ray apparatus 1.

The X-ray source unit 20 is provided inside the body unit 10 to emit electrons (E). As shown in FIG. 2, the X-ray source unit 20 includes a source unit 40 and a focusing unit 50.

At least one source unit 40 is provided to generate electrons (E). In the present exemplary embodiment, the source unit 40 includes two source units 40a and 40b to exemplify electrons E as dual electric fields. Hereinafter, for convenience of description, the source unit 40 will be described as an example including the first source unit 40a and the second source unit 40b.

In addition, the source part 40 is a hot electron emission method and carbon nanotube (CNT) based field emission that accelerates the heat generated by heating the filament inside the body unit 10 in a high voltage at a high voltage ( At least one method of field emission is employed to emit electrons (E). In the present exemplary embodiment, both the first and second source parts 40a and 40b generate and show electrons E by a carbon nanotube-based field emission method, but the present invention is not limited thereto.

That is, although not shown in detail, the first source part 40a of the source part 40 emits electrons E by a carbon nanotube-based field emission method, and the second source part 40b is a filament-based hot electron. Modifications of emitting electrons E in an emission manner are also possible. Alternatively, it is obvious that various modifications are possible, such that both the first and second source portions 40a and 40b emit electrons E in a filament-based hot electron emission scheme. In addition, various modifications such as three or more source portions 40 may be provided.

The detailed configuration of such a source unit 40 will be described in more detail with reference to FIG. 3.

As shown in FIG. 3, the source part 40 is formed in a thin plate shape, and has a negative electrode 41 for applying an electrode of a negative electrode, and an emitter 42 for emitting electrons E by being stacked on top of the negative electrode 41. And a thin plate-shaped patterning electrode 44 stacked on the emitter 42 to extract electrons E from the emitter 42.

The negative electrode 41 is formed in a relatively thin plate, that is, a thin plate, it may be formed of a metal material. The negative electrode 41 may be referred to as a cathode, that is, a cathode (-) electrode. Since the x-ray apparatus 1 according to the present invention operates in a vacuum, an alloy such as nickel, iron, cobalt, or a single transition metal may be employed as the material of the cathode electrode.

The emitter 42 is an electrode that controls the trajectory of electrons emitted, and includes a conductive material composed of a metal and a carbon-based material such as carbon nanotubes, which are nanomaterials and can emit high current per unit area.

Here, the negative electrode 41 and the patterning electrode 44 are formed with a cathode mesh 411 and a patterning mesh 441 formed in a mesh shape of a metal material, respectively, to guide the emission of electrons (E). The cathode mesh 411 and the patterning mesh 441 preferably have a plurality of openings formed between metal meshes, and the openings are formed in a hexagonal honeycomb shape. As the opening shapes of the cathode mesh 411 and the patterning mesh 441 are formed in a hexagon, the cathode mesh 411 and the patterning mesh 441 efficiently extract the electrons E, and the electrons E are the metal mesh. It can be maximized by the aperture ratio which is stably discharged without collision.

For reference, the cathode mesh 411 and the patterning mesh 441 are not limited to those having a hexagonal honeycomb shape, and various modifications in which a plurality of circular or rectangular openings are formed may be possible.

On the other hand, the upper part of the emitter 42, that is, between the emitter 42 and the patterning electrode 44, the emitter cover 43 having the cover hole 431 penetrated is stacked and electrons emitted from the emitter 42. The edge effect of (E) is prevented to guide the electrons (E) to be uniformly extracted. In addition, a first insulator 45 having a first insulating hole 451 therethrough is stacked between the emitter 42 and the emitter cover 43, and the emitter cover 43 and the patterning electrode 44 may be stacked. A second insulator 46 having a second insulating hole 461 therethrough is stacked therebetween. Therefore, between the emitter 42, the emitter cover 43, and the patterning electrode 44 is insulated by the first and second insulators 45 and 46.

In addition, the second support body 47 is stacked and supported under the negative electrode 41, and the opening 481 is formed through the second insulator 46 so that electrons E can be emitted. 48) are stacked. Therefore, the lower and upper portions of the source portion 40 are supported and protected by the first and second support members 46 and 47.

The first and second insulators 45 and 46 and the first and second support members 47 and 48 are all formed of an insulating material, which is exemplified as being made of a ceramic material.

Meanwhile, the negative electrode 41 and the patterning electrode 44 are provided with a negative electrode line 412 and a patterning electrode line 442, respectively, and are connected to an external power source. The negative electrode line 412 may be connected to the inside of the focusing unit 50 by passing through the first support 47 through an electrode hole 49 formed through the first support 47. In addition, the patterning electrode line 442 of the patterning electrode 44 is formed through the second insulator 46, the emitter cover 43, the first insulator 45, and the first support 47 to communicate with each other. The hole 49 may be connected to the inside of the focusing unit 50. The configuration in which the source unit 40 is installed in the focusing unit 50 will be described later in more detail along with the configuration of the focusing unit 50.

As described above, when the negative electrode 41 is applied to the negative electrode 41 supported by the first support 47, electrons E are emitted from the emitter 42. Electrons E emitted from the emitter 42 may be formed by the first insulating hole 451 of the first insulator 45, the cover hole 431 of the emitter cover 43, and the second of the second insulator 46. The insulating holes 461, the patterning mesh 441 of the patterning electrode 44, and the openings 481 of the second support 48 are sequentially passed to be emitted.

The focusing unit 50 focuses and emits electrons E generated from the source unit 40 to the outside. The focusing unit 50 includes a cup-shaped focusing body 51, and the source unit 40 described above is installed on the upper surface of the focusing body 51. To this end, at least one installation groove 54 or 55 in which the source unit 40 is installed is provided on the inclined surfaces 52 and 53 of the upper surface of the focusing unit 50.

In the present embodiment, as the source portion 40 is illustrated as including the first and second source portions 40a and 40b, the source portion 40 is illustrated as having the first and second installation grooves 54 and 55. . In addition, the first and second installation grooves 54 and 55 are inclined in a direction facing each other to the upper surface of the focusing unit 50, that is, the first and second inclined surfaces 52 inclined to be connected to each other in a V shape. Are formed in the (53).

The first and second slopes 52 and 53 are provided with first and second installation grooves 54 and 55 into which the first and second source portions 40a and 40b can be inserted, respectively. Here, the first and second inclined surfaces 52 and 53 are inclined to guide the electrons E emitted from the first and second source portions 40a and 40b toward the anode unit 30 to be described later. The first and second source portions 40a and 40b are inclinedly supported.

The first and second installation grooves 54 and 55 are formed in a shape corresponding to the first and second source portions 40a and 40b, respectively, so that the first and second installation grooves 54 and 55 are formed in the first and second installation grooves 54 and 55, respectively. The first and second source portions 40a and 40b are inserted, respectively, and can be aligned. 2 and 3, the first support 47, the negative electrode 41, and the emitter of the first source portion 40a with respect to the first installation groove 54 provided in the first inclined surface 52. 42), the first insulator 45, the emitter cover 43, the second insulator 46, the patterning electrode 44 and the second support 48 are sequentially stacked, whereby the positions are aligned.

4 and 5, the negative electrode line 412 and the patterning electrode line 442 are provided in the first and second installation grooves 54 and 55 provided in the focusing body 51. The first and second line holes 56 and 57 through which the first and second line holes 56 and 57 pass through are respectively formed. The first and second line holes 56 and 57 have a position and a number that can communicate with the negative electrode line 412 and the patterning electrode line 442, and the first and second installation grooves 54 and 55. Respectively formed through. As a result, the negative electrode line 412 and the patterning electrode line 442 extend from the negative electrode 41 and the patterning electrode 44 respectively stacked in the first and second installation grooves 54 and 55 to be focused. It can be connected to the power supply means not shown inside through.

The anode unit 30 is coupled to the body unit 10 so as to face the X-ray source unit 20 and generates X-rays L or light L by collision with electrons E, so that the body unit 10 To the outside of the. As shown in FIG. 1, the anode unit 30 is coupled to an upper portion of the body unit 10 so as to face the X-ray source unit 20, and the reflective surface 31 in which one surface facing the X-ray source unit 20 is inclined. ) The reflective surface 31 generates X-rays L by collision with electrons E to guide the outside of the body unit 10. For reference, although not shown in detail, the reflective surface 31 of the anode unit 30 may be disposed in a straight line to face a window (not shown) to redirect and guide the light L including X-rays. have.

Meanwhile, the light L including X-rays generated from the anode unit 30 may vary according to the material of the anode unit 30 and the magnitude of the voltage applied to the X-ray source unit 20 and the anode unit 30. , X-ray, visible light, infrared light, or ultraviolet light. In the present embodiment, the anode unit 30 is formed of any one of a metal made of copper, tungsten, manganese, molybdenum, and a combination thereof to generate X-rays (L).

For reference, when the reflective surface 31 of the anode unit 30 is formed of a material such as glass, not metal, a modified example of generating light L for illumination by collision with electrons E is possible.

An operation of the X-ray apparatus 1 having the X-ray source unit 20 according to the present invention having the above configuration will be described with reference to FIGS. 1 to 3.

First, as shown in FIG. 1, an X-ray source unit 20 is provided at a lower portion of the body unit 10, and an anode unit 30 is disposed at an upper portion of the body unit 10 so as to face the X-ray source unit 20. Prepared.

At this time, the X-ray source unit 20 is the first and second installation grooves in the first and second inclined surfaces 52, 53 inclined to the upper surface of the focusing body 51 of the focusing unit 50 having a cup shape ( 54 and 55 are provided. 2 and 3, the first and second source portions 40a and 40b of the source portion 40 are inserted and aligned with respect to the first and second installation grooves 54 and 55, respectively. That is, the first and second installation grooves 54 and 55 are provided to have a shape corresponding to the first and second source portions 40a and 40b, so that the first and second installation grooves 54 and 55 are provided. The first and second source portions 40a and 40b are stacked and installed, respectively, and the positions thereof are aligned.

In this way, the first and second source portions 40a and 40b are aligned with respect to the first and second installation grooves 54 and 55, respectively, so that the positions of the plate-shaped negative electrode 41 and the patterning electrode 44 are correct. It can be aligned so that no electrical problems such as an electric short are generated, and a plurality of source portions 40a and 40b are provided at the same time with respect to the focusing portion 50 so as to emit electrons E respectively. do.

The first source portion 40a installed in the first installation groove 54 emits electrons E by a field emission method using carbon nanotubes (CNT), wherein the electrons (E) are inclined first inclined surfaces ( 52, the electrons E are inclined toward the reflective surface 31 of the anode unit 30. For reference, the second source portion 40b may also emit electrons E together with or separately from the first source portion 40a in the second installation groove 55, and electrons of the second source portion 40b may be emitted. (E) The emission method is the same as that of the first source portion 40a, so that the emission rate of the electrons E can be increased. Alternatively, the electron E of the second source portion 40b may emit electrons E simultaneously or separately from the first source portion 40a by applying a hot electron emission method using a filament.

The electrons E emitted from the X-ray source unit 20 are guided and reflected to the inclined reflective surface 31 of the anode unit 30, thereby being converted to light L and not shown in the body unit 10. It is discharged to the outside through the window.

As described above, although described with reference to the preferred embodiment of the present invention, those skilled in the art various modifications and variations of the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

1: X-ray apparatus 10: Body unit
20: X-ray source unit 30: Anode unit
40: source portion 40a: first source
40b: second source 50: focusing unit
51: focusing body 52: first inclined plane
53: second slope 54: first mounting groove
55: 2nd installation groove E: Electronic

Claims (15)

At least one source unit generating electrons; And
At least one installation groove having a shape corresponding to each of the at least one source unit is provided to insert and align the at least one source unit, respectively, and focusing unit for focusing the electrons generated from the at least one source unit to the outside. ;
Including;
The at least one source unit,
A negative electrode for applying an electrode of the cathode;
An emitter stacked on the negative electrode to emit electrons;
An emitter cover stacked on the emitter to prevent edge effects;
A patterning electrode for patterning the electrons which are stacked on the emitter cover and emitted;
A first insulator stacked between the emitter and the emitter cover to insulate each other;
A second insulator laminated between the emitter cover and the patterning electrode to insulate each other;
A first support supporting a bottom of the negative electrode; And
A second support stacked on the second insulator and having an opening through which the electrons are emitted;
Each of which contains
An x-ray source unit having a first support, a negative electrode, an emitter, a first insulator, an emitter cover, a second insulator, a patterning electrode, and a second support, sequentially stacked and aligned with the installation groove. delete The method of claim 1,
The focusing unit has an X-ray source unit having a cup shape in which a plurality of installation grooves are provided on the upper surface so as to correspond to the number of the source units. The method of claim 1,
The source portion includes a first and second source portion for generating the electrons, respectively,
The focusing unit,
A focusing body having a cup shape and provided with first and second inclined surfaces facing the top surface and connected in a V shape; And
First and second installation grooves having shapes corresponding to the first and second source portions, respectively, provided on the first and second inclined surfaces to insert and align the first and second source portions;
X-ray source unit comprising a. The method of claim 1,
The at least one installation groove X-ray source unit through which a line hole through which the electrode line of the source portion passes. delete The method of claim 1,
The negative electrode and the patterning electrode is an X-ray source unit having a mesh (mesh) shape. The method of claim 1,
The negative electrode line extending from the negative electrode is connected to the inside of the focusing part through the first support,
And a patterning electrode line extending from the patterning electrode and passing through the second insulator, the emitter cover, the first insulator, and the first support to connect with the inside of the focusing unit. The method of claim 8,
And an electrode hole through which the negative electrode line and the patterning electrode line pass through the at least one installation groove of the focusing unit. A hollow body unit having a space therein;
An X-ray source unit provided in the body unit to emit electrons; And
An anode unit coupled to the body unit so as to face the X-ray source unit to generate X-rays or light by collision with the electrons and to guide the outside of the body unit;
Including;
The x-ray source unit,
At least one source unit generating the electrons; And
A focusing unit provided with at least one installation groove having a shape corresponding to the at least one source unit so that the at least one source unit can be inserted, and focusing and emitting electrons generated from the source unit to the outside;
Including;
The at least one source unit,
A negative electrode for applying an electrode of the cathode;
An emitter stacked on the negative electrode to emit electrons;
An emitter cover stacked on the emitter to prevent edge effects;
A patterning electrode for patterning the electrons which are stacked on the emitter cover and emitted;
A first insulator stacked between the emitter and the emitter cover to insulate each other;
A second insulator laminated between the emitter cover and the patterning electrode to insulate each other;
A first support supporting a bottom of the negative electrode; And
A second support stacked on top of the second insulator and having an opening through which the electrons are emitted;
Each of which contains
The first support, the negative electrode, the emitter, the first insulator, the emitter cover, the second insulator, the patterning electrode and the second support are sequentially stacked on the mounting groove and aligned with the installation. The method of claim 10,
The at least one source portion includes first and second source portions for generating the electrons,
The at least one installation groove X-ray apparatus including a first and a second installation groove, the first and second source portions are respectively inserted. The method of claim 11,
The focusing unit has a cup shape and is provided with first and second inclined surfaces connected to the upper surface in a V shape.
The first and second installation grooves are formed on the first and second slopes, respectively. The method of claim 11,
And first and second line holes through which the electrode lines of the first and second source portions pass through the first and second installation grooves, respectively. delete The method of claim 10,
The negative electrode line extending from the negative electrode is connected to the inside of the focusing part through the first support,
And a patterning electrode line extending from the patterning electrode to be connected to the inside of the focusing part through the second insulator, the emitter cover, the first insulator, and the first support.

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