KR102340337B1 - A manufacturing method of compact cylindrical x-ray tube - Google Patents

Abstract

The present invention relates to an X-ray tube and a method for manufacturing the same, and the X-ray tube according to the present invention comprises the steps of combining an inner insulating tube and the first cathode electrode such that a first cathode electrode is disposed therein; coupling the first gate electrode to the outside, maintaining a constant distance between the emitter and the second gate electrode formed on the surface of the second cathode electrode, maintaining a constant distance between the emitter and the second gate electrode coupling the second cathode electrode and the second gate electrode to the first cathode electrode and the first gate electrode, respectively, while maintaining the Combining an external insulating tube and coupling an anode electrode including a target for X-ray emission to the external insulating tube. As described above, by additionally installing a separate inner insulation tube formed to extend in the coaxial direction with the outer insulation tube between the cathode electrode and the outer insulation tube, the insulation distance between the electrodes can be increased. In addition, by forming the gate terminal portion of the gate electrode on the lower surface of the external insulating tube, it is possible to increase the insulation distance between the gate electrode and the anode electrode and at the same time improve the efficiency of the manufacturing process. In addition, the second cathode electrode and the second gate electrode are coupled to each of the first cathode electrode and the first gate electrode in a state where the distance between the emitter and the second gate electrode formed on the surface of the second cathode electrode is maintained at a constant level for internal insulation Even if a tolerance occurs when the tube and the first cathode electrode are coupled, the distance between the emitter and the second gate electrode can be maintained constant, so that electron emission efficiency can be improved.

Description

Method for manufacturing ultra-small cylindrical X-ray tube { A MANUFACTURING METHOD OF COMPACT CYLINDRICAL X-RAY TUBE}

The present invention relates to a method for manufacturing a micro-cylindrical X-ray tube, and more particularly, to a method for manufacturing a micro-cylindrical X-ray tube for maintaining a uniform distance between an emitter and a gate electrode set according to the emitter output specification of the X-ray tube.

In general, an X-ray tube is widely used by being applied to various inspection devices or diagnostic devices, such as for medical diagnosis, for non-destructive testing, or for chemical analysis.

Among them, the ultra-small cylindrical field emission type X-ray tube includes a cathode electrode and an anode electrode respectively disposed at both ends of a ceramic vacuum tube, an emitter disposed on the cathode electrode, and a gate electrode disposed between the cathode electrode and the anode electrode. It has a configuration that includes Here, electrons are emitted from the emitter by the electric field formed between the cathode electrode and the gate electrode, and the electrons emitted from the emitter are accelerated by the electric field formed between the anode electrode and the cathode electrode and collide with the target formed on the anode electrode side. X-rays are generated.

This carbon nanotube-based ultra-small cylindrical field emission type X-ray tube has the advantage of not generating power loss due to heat compared to the thermocathode type X-ray tube, and since the emitted electrons are emitted along the length direction of the carbon nanotube, the anode electrode The directionality of electrons toward the target of the side is excellent, so that the X-ray emission efficiency and focusing performance are improved. In addition, in the case of electron emission from the hot cathode, the electron emission characteristics are analogous to that of the analog due to the unique warm-up time of the filament. -Off) has the advantage of being able to operate digitally based on the characteristic.

On the other hand, in the case of the aforementioned ultra-small cylindrical field emission type X-ray tube, a very high potential difference of several kV to several tens of kV is formed between the cathode electrode and the gate electrode, and this potential difference depends on the current specification of the emitter. Maintaining the gap between the cathode and the gate electrode according to the current specification is a very important issue. Since the relationship between the voltage (electric field) applied to the gate electrode and the electrons emitted from the emitter formed on the surface of the cathode electrode is an exponential function, even if a slight potential difference occurs, there is a large difference in the amount of emitted electrons. .

In particular, in the case of the ultra-small cylindrical X-ray tube having the above-described structure, a brazing process of bonding the electrodes to the vacuum tube and heating is performed. There are cases where the design specifications between the two are not implemented as originally desired. In addition, the ceramic tube and various metal parts used in the ultra-small cylindrical X-ray tube inevitably cause manufacturing errors, and the errors exist within the range that affects the field emission. Since this ultimately leads to product defects, design methods considering tolerances are being studied. In particular, in the case of an ultra-small cylindrical X-ray tube, it is required to maintain a fine gap between the emitter and the gate electrode. It is formed at intervals or the intervals are not kept constant, but are formed at inclined intervals, which leads to a decrease in electron emission efficiency or a cause of defects.

Therefore, the present invention is made in consideration of such a problem, and the distance between the gate electrode and the emitter of the ultra-small cylindrical field emission type X-ray tube can be constantly maintained at a predetermined interval to match the output specification of the emitter, thereby improving the manufacturing process. A method for manufacturing an ultra-small cylindrical X-ray tube capable of improving efficiency is provided.

The micro-cylindrical X-ray tube according to one aspect of the present invention includes the steps of forming a first cathode electrode extending upwardly and sealing the lower surface of the inner insulating layer, the gate sealing the upper surface of the inner insulating layer and extending upward forming an electrode, maintaining a predetermined distance between the emitter and the gate electrode formed on the second cathode electrode at a predetermined interval, maintaining a constant distance between the emitter and the gate electrode combining the second cathode electrode and the first cathode electrode, extending and bonding the gate electrode so that the upper surface of the inner insulating layer and the lower surface of the outer insulating layer are hermetically sealed, and on the upper surface of the outer insulating layer and coupling an anode electrode including a target for X-ray emission.

A terminal for applying a voltage from the outside may be formed at a lower end of the first cathode electrode.

In the step of sealing the lower surface of the inner insulating layer and forming the first cathode electrode extending upward, at least a portion of the inner insulating layer is formed to protrude from the outer insulating layer.

The method may further include forming a focusing electrode connected to or spaced apart from the gate electrode on the upper portion of the gate electrode.

The emitter is formed of a nanostructure made of carbon nanotubes.

In the step of extending and bonding the gate electrode so that the upper surface of the inner insulating layer and the lower surface of the outer insulating layer are airtight, they may be coupled through a jig.

According to such a method for manufacturing a micro-cylindrical X-ray tube, the distance between the cathode and the gate electrode or between the emitter and the gate electrode can be maintained constant, thereby minimizing various tolerances occurring in the X-ray tube, thereby reducing the tube current ( The amount of electron emission from the emitter) can be kept constant by setting the distance between the emitter and the gate according to the specification.

1 is a perspective view showing a miniature cylindrical X-ray tube according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the ultra-small cylindrical X-ray tube shown in FIG. 1 .
FIG. 3 is a cross-sectional view of the cathode electrode shown in FIG. 1 .
4 to 7 are cross-sectional views illustrating a process for manufacturing an ultra-small cylindrical X-ray tube according to an embodiment of the present invention.

The features and effects of the present invention described above will become more apparent through the following detailed description in relation to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains can easily implement the technical idea of the present invention. will be able Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification is present, and includes one or more other features or It should be understood that the existence or addition of numbers, steps, operations, components, parts, or combinations thereof does not preclude the possibility of addition. Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. In addition, in the present application, expressions including upper and lower, such as upper, lower, upper, and lower, indicate a relative position with respect to the internal space of the device, rather than a division according to an absolute height.

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

1 is a perspective view illustrating an X-ray tube according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the X-ray tube shown in FIG. 1 .

1 and 2 , the micro-cylindrical X-ray tube 1000 according to an embodiment of the present invention includes an external insulating layer 400 and a cathode electrode 100 disposed at both ends of the external insulating layer 400 and It includes an anode electrode 500 and a gate electrode 300 disposed between the cathode electrode 100 and the anode electrode 500 . In addition, the cathode electrode 100 of the ultra-small cylindrical X-ray tube 1000 of the present invention is disposed in the inner insulating layer 200, and the lower end of the cathode electrode 100 seals the lower surface of the inner insulating layer 200, and A cathode terminal part 112 for electrical connection with the power supply circuit is formed.

2 and 3 , the cathode electrode 100 may include a first cathode electrode part 110 and a second cathode electrode part 120 .

The first cathode electrode unit 110 is disposed inside the inner insulating layer 200 , and includes a cathode terminal unit 112 coupled to a lower surface of the inner insulating layer 200 . The second cathode electrode part 120 is coupled to the upper portion of the first cathode electrode part 110 . The emitter 130 is an electron emission source emitting electrons and is formed on the upper surface of the second cathode electrode part 120 . The emitter 130 may be formed on a separate substrate and coupled to the second cathode electrode unit 120 , or may be formed directly on the surface of the second cathode electrode unit 120 . The emitter 130 may be formed of, for example, a plurality of nanostructures such as carbon nanotubes. When the emitter 130 is formed of carbon nanotubes, a plurality of carbon nanotubes are directly grown on the surface of the second cathode electrode part 120 by using chemical vapor deposition (CVD), or carbon nanotube paste. After printing, it can be formed by a method such as firing.

The inner insulating layer 200 is formed in a cylindrical tube shape to surround the side surface of the cathode electrode 100 . The inner insulating layer 200 may be formed of an insulating material such as ceramic, glass, or silicon, for example, of alumina ceramics.

The inner insulating layer 200 is formed in a cylindrical shape with upper and lower surfaces to accommodate the cathode electrode 100 therein, and the diameter of the inner insulating layer 200 is to be accommodated inside the outer insulating layer 400 . It is formed to be smaller than the diameter of the outer insulating layer 400 so as to The inner insulating layer 200 is disposed inside the outer insulating layer 400 to extend in the coaxial direction with the outer insulating layer 400, the insulating distance between the cathode electrode 100 and the gate electrode 300, and the cathode electrode ( In order to increase the insulating distance between the 100 ) and the anode electrode 500 , at least a portion of the inner insulating layer 200 is formed to be exposed to the outside of the outer insulating layer 400 .

The gate electrode 300 is disposed outside the internal insulating layer 200, and the lower end of the gate electrode 300 is coupled to the lower surface of the external insulating layer 400 to provide electrical connection with an external power supply circuit. A gate terminal part 312 for

Hereinafter, a method of manufacturing an ultra-small cylindrical X-ray tube according to an embodiment of the present invention will be described with reference to FIGS. 4 to 7 .

The method of manufacturing a micro-cylindrical X-ray tube according to an embodiment of the present invention includes the steps of forming the first cathode electrode 110 extending upwardly in a hermetic state on the lower surface of the inner insulating layer 200, the inner insulating layer Forming the gate electrode 300 extending upward in a state where the upper surface of the 200 is hermetically sealed, between the emitter 130 and the gate electrode 300 formed on the second cathode electrode 320 in advance Maintaining a constant interval at a set interval, combining the side surfaces of the second cathode electrode 120 and the first cathode electrode 110 while maintaining a constant interval between the emitter 130 and the gate electrode 300 Step, forming a gate electrode 300 that airtightly seals the upper surface of the inner insulating layer 200 and the lower surface of the outer insulating layer 400 and extends upward, and X-ray emission of the upper surface of the outer insulating layer 400 It consists of a step of forming while airtight with the anode electrode 500 including a target for.

The process of combining the internal insulating layer 200 and the first cathode electrode 110 so that the first cathode electrode 110 is disposed therein is formed at the lower end of the first cathode electrode 110 as shown in FIG. 4 . The cathode terminal part 112 is coupled to the inner insulating layer 200 on the lower surface.

Here, the cathode terminal unit 112 and the lower surface of the inner insulating layer 200 are bonded with an adhesive such as silver or lead, and the bonding part is heated to perform a brazing process to bond the first cathode electrode 110 made of a metal material. ) and the inner insulating layer 200 made of an insulating material can be completely combined.

At this time, in addition to the processing tolerance of the cathode terminal part 112 and the internal insulating layer 200, the material and adhesive amount of the adhesive used for bonding between the cathode terminal part 112 and the lower surface of the internal insulating layer 200 The thickness may vary depending on the tolerance at the part to be joined.

Thereafter, a process of bonding the first gate electrode 310 to the outside of the internal insulating layer 200 is performed. In the process of bonding the first gate electrode 310 to the internal insulating layer 200 , as shown in FIG. 5 , the gate coupling part 314 formed on the upper end of the first gate electrode 310 is joined to the internal insulating layer 200 . ) to the upper surface of the Here, the upper surfaces of the gate coupling part 314 and the inner insulating layer 200 are adhered with an adhesive such as silver or lead, and the first gate electrode part made of a metal material ( 310 and the inner insulating layer 200 made of an insulating material may be completely coupled.

Thereafter, a process of maintaining a constant distance between the emitter 130 and the second gate electrode 320 formed on the surface of the second cathode electrode 120 is performed. A distance d between the emitter 130 and the second gate electrode 320 is maintained constant as shown in FIG. 6 through a tool such as a jig.

Thereafter, as shown in FIG. 7 , the second cathode electrode in a state in which the distance d between the emitter 130 formed on the surface of the second cathode electrode 120 and the second gate electrode 320 is constantly maintained. A process of coupling 120 and the first cathode electrode 110 and coupling the second gate electrode 320 and the first gate electrode 310 is performed. At this time, the second cathode electrode 120 and the first cathode electrode 110 are coupled in a state where the distance d between the emitter 130 and the second gate electrode 120 is kept constant, and the second gate By combining the electrode 320 and the first gate electrode 310 , it is possible to minimize the tolerance generated when the cathode terminal part 112 and the lower surface of the internal insulating layer 200 are coupled, so that the emitter 130 and the second gate Since the distance d between the electrodes 320 may be maintained relatively constant, electron emission efficiency may be improved.

In this case, the process of combining the second cathode electrode 120 and the first cathode electrode 110 and the process of combining the second gate electrode 320 and the first gate electrode 310 may be simultaneously performed, or both processes It is also possible to perform one of the processes first, followed by the other.

After the second cathode electrode 120 and the first cathode electrode 110 and the second gate electrode 320 and the first gate electrode 310 are combined, as shown in FIG. 2 , the second gate electrode 320 is A process of combining the focusing electrode 600 for focusing the electron beam traveling toward the anode electrode 500 on the upper portion may be performed.

Thereafter, a process of bonding the external insulating layer 400 to the outside of the first gate electrode 310 so as to extend in the coaxial direction with the internal insulating layer 200 is performed. As shown in FIG. 3 , the gate terminal part 312 formed at the lower end of the first gate electrode 310 is coupled to the lower surface of the external insulating layer 400 . At this time, when the first gate electrode 310 and the external insulating layer 400 are coupled, at least a portion of the internal insulating layer 200 is coupled to be exposed to the outside of the external insulating layer 400 .

Separately from the coupling of the first gate electrode 310 and the external insulating layer 400 , a process of coupling the external insulating layer 400 and the anode electrode 500 is performed. The bonding process of the external insulating layer 400 and the anode electrode 500 may be performed before or after the external insulating layer 400 is coupled to the gate electrode 300 .

In this way, in a state in which the coupling between the external insulating layer 400 and the gate electrode 300 and the coupling between the external insulating layer 400 and the anode 500 are completed, a low-temperature brazing process is performed to make a product made of a metal material. 1 The gate electrode part 310 and the anode electrode 500 and the external insulating layer 400 made of an insulating material may be completely coupled.

According to this manufacturing process, the lower space of the internal insulating layer 200 is sealed through the coupling of the cathode electrode 100 and the internal insulating layer 200 , and the bonding of the gate electrode 300 and the internal insulating layer 200 and Through the coupling of the gate electrode 300 and the external insulating layer 400 , the space between the internal insulating layer 200 and the external insulating layer 400 is sealed, and the external insulating layer 400 and the anode electrode 500 are The upper space of the outer insulating layer 400 is sealed through the bonding, and the inner space of the finally manufactured ultra-small cylindrical X-ray tube 1000 is maintained in a vacuum-sealed state.

In the above, it has been mainly described that the tolerance occurs depending on the amount of adhesive used for bonding between the cathode terminal part 112 and the lower surface of the internal insulating layer 200, but the internal insulating layer 200, the first cathode electrode 110, A tolerance may also occur in the manufacturing process of the first gate electrode 310 and the second cathode electrode 120 . Even when tolerances occur in the manufacturing process of the internal insulating layer 200 , the first cathode electrode 110 , the first gate electrode 310 , and the second cathode electrode 120 , the second cathode electrode 120 is used with a tool such as a jig. ) The second cathode electrode 120 and the first cathode electrode 110 are coupled to each other while maintaining a constant distance between the emitter 130 and the second gate electrode 320 formed on the surface, and the second gate electrode Even after the coupling is completed by coupling the 320 and the first gate electrode 310 , the distance between the emitter 130 and the second gate electrode 320 can be maintained constant, so that the electron emission efficiency can be improved.

In the foregoing detailed description of the present invention, although it has been described with reference to preferred embodiments of the present invention, those skilled in the art or those having ordinary knowledge in the art will have the spirit of the present invention described in the claims to be described later. And it will be understood that various modifications and variations of the present invention can be made without departing from the technical scope.

1000: X-ray tube 100: cathode electrode
110: first cathode electrode part 112: cathode terminal part
120: second cathode electrode 130: emitter
200: inner insulating layer 300: gate electrode
310: first gate electrode part 312: gate terminal part
314: gate coupling part 320: second gate electrode part
400: outer insulating layer 500: anode electrode
520: target 600: focusing electrode

Claims (6)

forming a first cathode electrode extending upwardly in an airtight state on the lower surface of the inner insulating layer;
coupling a first gate electrode extending to an upper portion of the inner insulating layer with the inner insulating layer in a state where the upper surface of the inner insulating layer is hermetically sealed;
maintaining a distance between the emitter formed on the second cathode electrode and the second gate electrode at a predetermined interval;
coupling side surfaces of the second cathode electrode and the first cathode electrode while maintaining a constant distance between the emitter and the second gate electrode;
sealing the upper surface of the inner insulating layer and the lower surface of the outer insulating layer and coupling a first gate electrode extending over the inner insulating layer with the outer insulating layer; and
A method of manufacturing an ultra-small cylindrical X-ray tube comprising the step of forming an upper surface of the outer insulating layer airtightly with an anode electrode including a target for X-ray emission. According to claim 1,
A method of manufacturing an ultra-small cylindrical X-ray tube, characterized in that a terminal for applying a voltage from the outside is formed at the lower end of the first cathode electrode. According to claim 1,
In the step of forming the first cathode electrode extending upwardly in an airtight state on the lower surface of the inner insulating layer, at least a portion of the inner insulating layer is formed to protrude from the outer insulating layer. A method of manufacturing the tube. According to claim 1,
The method of manufacturing a micro-cylindrical X-ray tube, characterized in that it further comprises the step of forming a focusing electrode that is connected to or spaced apart from the upper portion of the gate electrode. According to claim 1,
The emitter is a method of manufacturing a micro-cylindrical X-ray tube, characterized in that formed of a nanostructure made of carbon nanotubes. delete

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