KR20160056592A - Cnt x-ray source with glass tube housing and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an X-ray source which can couple a cathode portion having a carbon nano tube (CNT) electron emitter with an anode portion within a glass housing without using a brazing process, and a method of manufacturing the X-ray source. According to the present invention, provided is a method of manufacturing an X-ray source by point-welding a cathode portion on one end of the glass housing having a tubular shape, and thermally bonding an anode portion with the other end, as well as the X-ray source manufactured by the method. Air is extracted from an inner portion of the glass housing through an air discharge tube to form a vacuum condition in the glass housing, and the air discharge tube is heated and then sealed.

Description

Technical Field [0001] The present invention relates to a carbon nanotube X-ray source having a glass tube housing, and a method of manufacturing the same. BACKGROUND ART < RTI ID = 0.0 &

The present invention relates to an X-ray source having carbon nanotubes as electron emitting means, and more particularly to an X-ray source in which a vacuum tube housing of an X-ray source is made of glass.

Recently, an X-ray source using a nanomaterial such as a carbon-nano-tube (CNT) has been introduced for miniaturization of an X-ray generator. CNT is a carbon isotope composed of carbon, which is a material in which one carbon is bonded to another carbon atom in a hexagonal honeycomb pattern to form a tube, has excellent mechanical properties and electrical selectivity, and has excellent field emission characteristics. Therefore, when applied to an X-ray source of an X-ray apparatus, it is possible to emit an electron beam (electric field) even at room temperature with low power and to emit electrons up to 90% The field concentration effect is very good.

The X-ray source for emitting X-rays includes a cathode for providing electrons, a gate for exciting electrons provided in the cathode, a focus for accelerating and accelerating electrons excited by the gate to the anode, And an anode for generating an X-ray by collision.

Hereinafter, an X-ray source according to the prior art will be described with reference to FIG.

As shown in FIG. 1, an X-ray source using a carbon-nano-tube (CNT) is connected to a positive electrode and is made of a metal material such as tungsten. (+) Electric field for exciting electrons on the surface of the cathode (21), and a negative electrode (21) having a negative electrode A focus 23 which is an electrode which forms a predetermined electric field so as to concentrate the electrons emitted from the CNT tip by the gate 22 and the center of the anode 11, 11 and the cathode 21 and forms a space in which electrons emitted from the CNT tip are accelerated, and a window 30 made of ceramics and a window 30 through which X-rays emitted from the anode 11 are transmitted 40).

On the other hand, in the case of a CNT X-ray source, an electrode such as a cathode, a cathode, a gate and a focus is coupled to the housing 30 through a brazing process at a temperature of 600 ° C or higher. Therefore, in the case of a CNT X-ray source, a ceramic having a high heat resistance was used as the material of the housing 30. [ Then, the brazed joint B bonded through the brazing process is subjected to high temperature treatment with a metal material and metalized.

Recently, with the development of X-ray imaging technology, it is required to acquire a high-quality image. Particularly, in order to obtain a three-dimensional X-ray image, an X-ray output of 120 kVp or more is required. However, in the case of a conventional X-ray source in which electrodes are brazed to the ceramic housing 30 of the above-described type, when the above-mentioned high-output operation with a tube voltage of 120 kVp or more is performed, the brazed joint B is very sensitive to high- Strength may drop. Further, since the inside of the ceramic housing 30 is kept in a vacuum state, if the mechanical strength is lowered, the durability of the X-ray source may be significantly deteriorated.

Therefore, there is a need to fabricate a CNT X-ray source using a glass material having excellent sealing properties and excellent mechanical strength for securing a vacuum degree.

It is an object of the present invention to provide an X-ray source capable of bonding electrodes including a CNT element in a glass tube housing without using a brazing method.

According to another aspect of the present invention, there is provided a method of manufacturing a terminal, comprising the steps of: (S10) forming a terminal through an electrode terminal on one side of a glass-made housing having an air discharge tube and a first end opened; A negative electrode alignment step of inserting a negative electrode portion having a CNT tip through the first end into the housing to physically contact the negative electrode portion and the electrode terminal, (S30) aligning the positive electrode portion to seal the first end portion of the housing with the positive electrode portion (S40), forming a vacuum inside the housing through the air discharge pipe (S41), and sealing the air discharge pipe (S42); and a vacuum forming and sealing step Ray source.

Wherein the cathode portion includes at least one of a cathode having the CNT tip formed thereon, a gate electrically insulated from the cathode and disposed between the cathode and the anode portion, and a focus, A first electrode terminal in physical contact with the cathode, and a second electrode terminal in physical contact with the cathode.

It is preferable that the method further includes a negative electrode bonding step of bonding the negative electrode portion and the electrode terminal contact portion before the step of bonding the positive electrode portion (S25) after the step (S20) of aligning the negative electrode portion (S30).

For example, the contact portion between the cathode portion and the electrode terminal can be contacted.

The auxiliary electrode may include a gate for exciting electrons in the CNT tip and a focus for accelerating electrons excited in the CNT tip toward the anode.

The anode connecting step S40 may include heating the first end side of the glass housing to press-fit the anode portion to the glass housing side, press-fit the anode portion into the glass housing, Can be performed.

According to the present invention, since CNT is used as an electron emitter and the housing is made of glass rather than ceramic, a brazing method is not used, so that high power X-ray emission through high voltage application is easy.

In addition, when a brazing process is used, a vacuum chamber for the brazing process is required, since the brazing process is required in a vacuum environment. However, when forming the housing with glass, the parts are joined to the housing by a simple spot welding and thermal bonding process And because it is possible to create a vacuum with an air discharge tube, an X-ray source can be manufactured with a compact manufacturing facility.

1 is a conceptual diagram showing an X-ray source according to the prior art,
FIG. 2 is an exploded view showing an assembling process of an X-ray source according to the present invention,
FIG. 3 is a conceptual view illustrating a process of bonding a cathode side of a X-ray source to a first electrode terminal of a glass tube according to the present invention;
4 is a plan view showing a first electrode terminal for applying a voltage to a gate and a focus in a glass tube of an X-ray source according to the present invention,
FIG. 5 is a conceptual view illustrating a process of bonding a bottom surface of a cathode portion of an X-ray source according to the present invention to a second electrode terminal for applying a voltage to a cathode,
FIG. 6 is a conceptual diagram illustrating a process of forming a vacuum in an X-ray source according to the present invention. FIG.
FIG. 7 is a conceptual diagram showing the completion state of an X-ray source according to the present invention, and
8 is a flowchart illustrating a manufacturing process of an X-ray source according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The shape and the size of the elements in the drawings may be exaggerated for clarity and the same elements are denoted by the same reference numerals in the drawings.

And throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between. Furthermore, when a component is referred to as being "comprising" or "comprising", it is to be understood that this does not exclude other components, do.

As shown in FIG. 2, the present embodiment includes a glass housing 130 having a first end opened and a narrow air discharge pipe 131 formed at a second end thereof; A negative electrode portion 120 fixed to the second end side of the housing 130 and composed of a single assembly of the negative electrode 121 and the gate 122 and the focus 123 on which the CNT tip 124 is deposited, And an anode portion 110 that seals the first end of the cathode 130 and provides a cathode 112 with a target 111 in a direction toward the cathode portion 120.

A first electrode terminal 150 made of metal is formed around the glass housing 130 and exposed to the inside and the outside of the glass housing 130. This can be achieved by thermally bonding the glass housing 130 before the glass housing 130 is hardened in a molten state or by inserting the junctions of the glass housing 130 and the first electrode terminal 150 with corresponding stepped shapes. In particular, the glass housing 130 and the first electrode terminal 150 can be integrally formed using a thermal bonding process in which the substrate is press-fitted and then cooled in a heated state.

At the second end of the glass housing 130, a second electrode terminal 160 made of a metal that connects the inside and the outside of the glass housing 130 is integrally formed. The second electrode terminal 160 may be passed through the glass housing 130 in a melted state of the glass housing 130 and then cooled to be integrally formed.

3, the cathode 121 is electrically disconnected by the gate 122 and the focus 123 and the insulating spacer 125 therebetween, and the gate 122 and the focus 123 are electrically isolated from each other And are electrically connected by an auxiliary electrode covering the outer circumferential surface. The gate 122 and the focus 123 of the cathode portion 120 are in contact with the first electrode terminal 150 formed around the glass housing 130 through the auxiliary electrode and the cathode 121 is in contact with the glass housing 130, The second electrode terminal 160 is in contact with the second end of the second electrode terminal.

The cathode portion 120 is inserted and aligned on the second end side inside the glass housing 130 through the cathode fixing jig 200 made of a conductor. 3 and 4, a connection part 151 is provided on the inner surface of the first electrode terminal 150, and the connection part 151 is formed in the form of a leaf spring and acts as an elastic piece. In addition, the second electrode terminal 160 in the glass housing 160 is in the form of a bent leaf spring, and acts as an elastic piece.

Therefore, when the cathode part 120 is inserted into the second end side of the glass housing 130 with the cathode part fixing jig 200, the auxiliary part 120 connecting the gate 122 and the focus 123 of the cathode part 120 The electrode maintains a physical and electrical contact state with the first electrode terminal 150 due to the elasticity of the connection portion 151 of the first electrode terminal 150 and the cathode 121 maintains a state of being in contact with the second electrode terminal 160 And maintains a physical and electrical contact state by elasticity.

When a current is applied to the cathode fixing jig 200 after connecting the welding electrode (not shown) to the outside of the first electrode terminal 150 after the cathode portion 120 is aligned, a current flows in a direction indicated by a dotted line. The auxiliary electrode connecting the gate 122 and the focus 123 is spot welded at the portion S of the first electrode terminal 150 which contacts the connection portion 151. [

5, the welding paper 210 is inserted through the air discharge pipe 131 to connect to the cathode 121 and a welding electrode (not shown) is attached to the outer side of the second electrode terminal 160, The spot welding is performed at the portion S where the cathode 121 and the second electrode terminal 160 are in contact with each other.

As described above, the cathode portion 120 may be firmly coupled to the glass housing 130 through a process of spot-welding the cathode portion 120 into the glass housing and then performing a spot welding on a portion requiring electrical connection.

As shown in Fig. 6, the anode portion 110 seals the first end of the glass housing 130. This is accomplished by thermally bonding the anode 110 with the glass housing 130 after pressurizing and then cooling the anode 130 with the glass housing 130 heated.

The cathode portion 120 and the anode portion 110 can be firmly coupled to each other in the glass housing 130 through the above-described process. Thereafter, the air discharge pipe 131 of the glass housing 130 is connected to an external vacuum pump (not shown), and is connected to the housing 130 through the air discharge pipe 131 connected to the inside of the housing through the air discharge port 132. [ The inside air is exhausted to create a vacuum state.

7, when a vacuum is formed inside the glass housing 130, the air outlet 132 is sealed to form the sealing portion 132 ', and then the air discharge tube 131 is removed to remove the X- It completes. The sealing portion 132 'is formed by heating the air discharge pipe 131 around the air discharge port 132 to seal the air discharge port 132.

As shown in FIG. 8, an X-ray source according to the present invention is manufactured through the following process. First, a glass housing 130 having an electrode terminal is formed (S10) by forming an electrode terminal through one side of a glass-made housing having an air discharge pipe and a first end opened, and a CNT tip The negative electrode 121 is inserted into the housing 130 and physically contacted with the negative electrode 120 and the electrode terminal to form a negative electrode 121, a gate 122 and a focus 123 electrode, a CNT tip 124, (125) is arranged at a predetermined position (S20). Thereafter, the aligned cathode portion 120 is spot welded with the auxiliary electrode to bond the cathode portion 120 to the housing 130 (S25). When the cathode part 120 is bonded and fixed within the housing 130, the anode part 110 is thermally bonded to the first end part of the housing 130 to seal the first end part (S30). Thereafter, a vacuum is formed inside the housing through the air discharge tube (S41), and the air discharge tube is sealed (S42) to complete a vacuum X-ray source (S40).

In the present embodiment, the air discharge pipe 131 is formed at the second end of the glass housing 130, but is preferably selected as a position where air is drained from the glass housing 130 and then sealed. But is not limited thereto.

As described above, the X-ray tube having a tube-shaped housing made of glass is hardly influenced by the high-voltage high-power environment, for example, the coupling relationship of components even under a tube voltage of 120 kVp or more for CT imaging. Therefore, high-power driving can be achieved for obtaining a high-quality or three-dimensional X-ray image.

In addition, the cost of the X-ray source can be reduced because the glass is less expensive than the ceramic and the thermal bonding can be performed at a lower cost than the brazing process.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be clear to those who have.

10: anode part 11: anode
20, 120: cathode part 21, 121: cathode
22, 122: gate 23: focus
24, 124: CNT tips

Claims (8)

(S10) a terminal forming step of forming an electrode terminal through one side of a glass-made housing in which an air discharge pipe is formed and a first end is opened,
(S20) a negative electrode alignment step of inserting a negative electrode portion having a CNT tip through the first end portion into the housing to physically contact the negative electrode portion and the electrode terminal,
(S30) a positive electrode portion bonding step of sealing the first end portion of the housing to the positive electrode portion,
(S40), a vacuum is formed inside the housing through the air discharge tube (S41), and the air discharge tube is sealed (S42)
≪ / RTI >
The method according to claim 1,
Wherein the cathode portion includes at least one of a cathode having the CNT tip formed thereon, a gate electrically insulated from the cathode, and a focus disposed between the cathode and the anode portion,
Wherein the electrode terminal comprises a first electrode terminal physically contacting at least one of the gate and the focus, and a second electrode terminal physically contacting the cathode.
The method according to claim 1 or 2,
After the cathode section alignment step (S20), before the anode section bonding step,
(S25). The method of manufacturing an X-ray source according to claim 1, further comprising a negative electrode bonding step of bonding the negative electrode portion and the electrode terminal contact portion.
The method of claim 3,
(S25) The method of manufacturing an X-ray source according to any one of the preceding claims, wherein the step of joining the cathode section contacts the contact section between the cathode section and the electrode terminal.
A tube-shaped housing made of a glass material,
An electrode terminal passing through one side of the housing,
A cathode portion physically contacting the electrode terminal inside the housing and including a CNT tip; And
And an anode portion coupled to one end of the housing to face the CNT tip,
Ray source.
The method of claim 5,
Wherein the cathode portion includes at least one of a cathode having the CNT tip formed thereon, a gate electrically insulated from the cathode, and a focus disposed between the cathode and the anode portion,
Wherein the electrode terminal comprises a first electrode terminal physically contacting at least one of the gate and the focus, and a second electrode terminal physically contacting the cathode.
The method according to claim 5 or 6,
And the contact portion of the cathode portion and the electrode terminal is spot welded.
The method of claim 5,
And a sealed air outlet provided at one side of the housing.

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