KR102427665B1 - High voltage x-ray generator - Google Patents

Abstract

A high voltage X-ray generator is disclosed. According to an embodiment of the present invention, the high voltage X-ray generator is a field emission type high voltage X-ray generator including a unipolar type cold cathode X-ray tube to which a center ground is inapplicable. The cold cathode x-ray tube comprises: an anode; a cathode, wherein the cathode is connected to a predetermined cathode voltage, and a reference potential has a maximum value of the predetermined cathode voltage; and a rectification unit including an anode region rectification part connected to the anode to supply a predetermined anode voltage and a cathode region rectification part connected to the cathode to supply the predetermined cathode voltage. According to the present invention, the cathode of the X-ray tube is connected to the predetermined cathode voltage so that the reference potential of a circuit has the maximum value of the predetermined cathode voltage, thereby providing the high voltage X-ray generator capable of producing an effect of a cathode voltage control even in the unipolar (unipolar) type X-ray tube.

Description

High voltage X-ray generator {HIGH VOLTAGE X-RAY GENERATOR}

The present invention relates to a high-voltage X-ray generator, and more particularly, the cathode of the X-ray tube is connected to a predetermined negative voltage so that the reference potential of the circuit has the maximum value of the predetermined negative voltage, thereby realizing a positive voltage control effect. It relates to a high-voltage X-ray generator.

[Project unique number] D2121037
[Business name] Gyeonggi-do
[Research Management Specialized Institution] Gyeonggi-do Economic Science Promotion Agency
[Research project name] Corporate-led general
[Research project name] Carbon nanotube-based digitally controlled X-ray generation bipolar high-precision, high-voltage power generation technology development
[Research institute] Sangik Electronics Co., Ltd.
[Research Period] 2021. 8. 1. ~ 2022. 7. 31.
In order to generate X-rays, a method of accelerating electrons emitted from a vacuum tube and striking the accelerated electrons on an anode electrode is used.

As a method of emitting electrons, a thermal electron emission type and a field electron emission type are mainly used. A typical X-ray tube uses the most thermal electron emission type for heating a filament in a vacuum glass tube.

Recently, research on field electron emission type X-ray devices that are easy to digitally control are being actively researched, and a commercialized thermionic emission type X-ray generator uses a current source to provide a current flowing to a tungsten filament, which is an electron emission source. On the other hand, the field electron emission type X-ray generator employs a method of emitting electrons by applying a high voltage to a metal tip or carbon nanotube.

Here, the field electron emission type X-ray generator is driven by grounding the cathode electrode and applying a positive voltage to the gate and anode electrodes.

Republic of Korea Patent Registration No. 10-1487970 (Jan. 23, 2015) "High-frequency X-ray generator" Republic of Korea Patent Publication No. 10-2009-0030531 (2009.03.25.) "X-ray high voltage generator"

In the high voltage X-ray generator according to an embodiment of the present invention, the cathode of the X-ray tube is connected to a predetermined negative voltage so that the reference potential of the circuit has the maximum value of the predetermined negative voltage, so that unipolar (unipolar) type X An object of the present invention is to provide a high-voltage X-ray generator capable of realizing an effect according to the bipolar voltage control in a ray tube.

In addition, the high voltage X-ray generator according to an embodiment of the present invention applies a high voltage to the cathode grounded X-ray tube by dividing it into an anode region and a cathode region, thereby exerting a load distribution effect on components during boosting and back pressure, thereby reducing costs. An object of the present invention is to provide a high-voltage X-ray generator that can.

In addition, the high-voltage X-ray generator according to an embodiment of the present invention is a high-voltage X-ray generator in which the impedance of the circuit is minimized compared to the unipolar voltage control method, thereby reducing tube current loss and securing the quality margin of high-voltage components. aims to provide

The problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to the above object, a high voltage X-ray generator according to an embodiment of the present invention is a field emission type high voltage X-ray generator including a cold cathode X-ray tube that is unipolar and cannot apply a center ground, the cold cathode X-ray tube. Silver includes an anode and a cathode, wherein the cathode is connected to a predetermined negative voltage, and a reference potential has a maximum value of the predetermined negative voltage. An anode region connected to the anode to supply a predetermined anode voltage and a rectifying section including a rectifying section and a cathode region rectifying section connected to the cathode to supply a predetermined cathode voltage.

Here, the high voltage X-ray generator includes: a power generator including a power source and a plurality of switching elements; a back-pressure unit boosting the voltage supplied from the power generator; the rectifier rectifies the voltage boosted from the back-pressure unit, and the cold cathode X-ray tube is connected to the output terminal of the rectifier to generate X-rays.

delete

Here, the positive region rectifying portion and the cold electrode region rectifying portion are connected in parallel with the back pressure portion.

According to the embodiments of the present invention, there are at least the following effects.

According to the high voltage X-ray generator according to the present invention, the cathode of the X-ray tube is connected to a predetermined negative voltage so that the reference potential of the circuit has the maximum value of the predetermined negative voltage, so that even in a unipolar (unipolar) type X-ray tube, there is a positive polarity. A high-voltage X-ray generator capable of exhibiting an effect according to voltage control is provided.

In addition, by applying a high voltage to the cathode-grounded X-ray tube by dividing it into an anode region and a cathode region, a load distribution effect for components is exhibited during boosting and backing, thereby reducing costs.

In addition, compared to the unipolar voltage control method, the impedance of the circuit is minimized, so advantages such as reduction of tube current loss and securing of quality margin of high voltage components can be expected.

The effect according to the present invention is not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a schematic circuit diagram showing the configuration of a high voltage X-ray generator according to the present invention;
2 is a schematic explanatory view of a cold cathode X-ray tube of a high voltage X-ray generator according to the present invention.

Since the present invention can apply various transformations and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. Effects and features of the present invention, and a method of achieving them, will become apparent with reference to the embodiments described below in detail in conjunction with the drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Before the description, the terms described in the detailed description will be described. In the following embodiments, terms such as first, second, etc. are used for the purpose of distinguishing one component from another, not in a limiting sense. Therefore, it goes without saying that the first component mentioned below may be the second component within the spirit of the present invention. Also, the singular expression includes the plural expression unless the context clearly dictates otherwise. In addition, terms such as 'comprise' or 'have' mean that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, and one or more other features or components It does not preclude the possibility of adding

In addition, in the drawings, the size of the components may be exaggerated or reduced for convenience of description. For example, since the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of description, the present invention is not necessarily limited to the illustrated bar.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals, and overlapping description thereof will be omitted.

In the high voltage X-ray generator according to an embodiment of the present invention, the cathode of the X-ray tube is connected to a predetermined negative voltage so that the reference potential of the circuit has the maximum value of the predetermined negative voltage, so that unipolar (unipolar) type X It relates to a high-voltage X-ray generator capable of exerting an effect according to the bipolar voltage control even in a ray tube.

1 is a schematic circuit diagram showing the configuration of a high voltage X-ray generator according to the present invention, and FIG. 2 is a schematic explanatory diagram of a cold cathode X-ray tube of the high voltage X-ray generator according to the present invention.

The high voltage X-ray generating apparatus 1000 according to an embodiment of the present invention includes a power generating unit 100 , a back pressure unit 200 , a rectifying unit 300 , and a cold cathode X-ray tube 400 .

The high voltage X-ray generator 1000 according to the present embodiment is characterized in that the cold cathode X-ray tube is applied to a unipolar (unipolar) method. More specifically, it is characterized in that it is applied to a cold cathode X-ray tube to which a center ground cannot be applied as a unipolar method.

The power generator 100 includes a rectifier circuit 120 , a smoothing capacitor 130 , and an inverter circuit 140 .

The rectifier circuit 120 receives a commercial AC voltage from the external power source 110 and converts it into a DC voltage.

The smoothing capacitor 130 is configured to smooth the output voltage of the rectifier circuit. It may be referred to as a converter including the rectifier circuit 120 and the smoothing capacitor 130 .

That is, the commercial AC voltage supplied from the external power source 110 becomes a DC power supply unit through the converter.

The inverter circuit 140 is configured to convert the DC voltage from the smoothing capacitor 130 into a high frequency AC voltage.

The back-pressure unit 200 is configured to boost the high-frequency AC voltage output from the inverter circuit 140 .

In this embodiment, the back voltage unit 200 is provided as a high voltage transformer (a step-up transformer), and when an AC voltage output from the inverter circuit is input to the primary winding, the voltage is boosted to a high voltage and output to the secondary winding.

Since the above-described rectifier circuit 120 , smoothing capacitor 130 , inverter circuit 140 , and back voltage unit 200 are well-known configurations, detailed descriptions thereof will be omitted.

The rectifying unit 300 is configured to enable bipolar control of the unipolar cold-cathode X-ray tube 400 , which is the subject of the present embodiment.

In this embodiment, the rectifying unit 300 includes an anode region rectifying portion 310 and a cathode region rectifying portion 320 .

The anode region rectifying part 310 is connected to the anode 430 of the cold cathode X-ray tube 400 to apply an anode voltage, and the cathode region rectifying part 320 is connected to the cold cathode X-ray tube 400 and the cathode 410 . It is configured to supply negative voltage. Here, the anode region rectifying part 310 and the cathode region rectifying part 320 are connected in parallel with the back pressure part 200 . And the anode region rectifying part 310 and the cathode region rectifying part 320 are connected in series with each other.

The cold cathode X-ray tube 400 may include a cathode 410 , an emitter 420 , an anode 430 , a target 440 , and a gate electrode 450 .

The cathode 410 is disposed at one end of the cold cathode X-ray tube 400 and the anode 430 is disposed at the other end of the cold cathode X-ray tube 400 to face each other. Specifically, the anode 430 is disposed to be spaced apart in a direction perpendicular to the upper surface of the cathode 410 .

The gate electrode 450 may serve to extract electrons from the emitter 420 .

The gate electrode 450 may be positioned between the emitter 420 and the anode 430 . The gate electrode 450 may be disposed closer to the emitter 420 than the anode 430 .

The gate electrode 450 may be positioned above the cathode 410 , and may include an opening at a position corresponding to the emitter 420 . The opening may be equipped with a mesh formed in a metal mesh shape. The mesh can be spaced apart from the upper surface of the emitter 420 by a predetermined distance, and guides the electric field to be well applied to the middle of the emitter 420 so that electron extraction from the emitter 420 is uniform. play a role Here, the shape of the mesh is not limited.

The emitter 420 may include a carbon nanotube. The emitter 420 may be arranged in the form of a dot array or may have the form of a yarn made by twisting carbon nanotubes.

Meanwhile, as described above, the present embodiment is characterized in that the cold cathode X-ray tube 400 is applied to a unipolar (unipolar) method. Specifically, it is a unipolar CNT (carbon nanotube) X-ray tube/X-ray tube, characterized in that it is applied to the cold cathode X-ray tube 400 to which a center ground cannot be applied. More specifically, this embodiment is a CNT X-ray tube in which the voltage applied between the cathode 410 and the emitter 420 is 70 kV or more, and more preferably 80 kV or more, it is a unipolar method and that the center ground cannot be applied. to be applied.

In this embodiment, the application of 120 kV will be described as an example.

Accordingly, in the present embodiment, the reference potential of the circuit of the high voltage X-ray generator 1000 is set to be the maximum value of the cathode voltage, not 0V. The cathode 410 is connected to a predetermined negative voltage, and at this time, the reference potential becomes the maximum value of the negative voltage. For example, when a high voltage of 120 kV is applied to the cold cathode X-ray tube 400 , the reference potential of the circuit is implemented as -60 kV instead of 0 V.

In other words, unlike in general, the unipolar type X-ray tube uses the reference potential as 0V, in this embodiment, the reference potential is set at the cathode 410, but not 0V, but -60kV. Accordingly, the cathode 410 is configured such that the reference potential of the circuit has the maximum value of the predetermined cathode voltage (-60 kV based on the drawing).

In general, in the case of unipolar control, when the cathode 410 is grounded, the secondary-side rectifying unit of the back pressure unit 200 is rectified to unipolarity and output. For example, when a high voltage of 120 kV is applied to the X-ray tube, the secondary-side rectifying unit of the back pressure unit 200 is unipolarly rectified to realize 0 to +120 kV.

And in the case of bipolar control, the back pressure unit 200 and the secondary side rectifying unit 300 are rectified to be bipolar through the center ground of the X-ray tube. For example, when a high voltage of 120 kV is applied to the X-ray tube, the secondary-side rectifying unit 300 of the back pressure unit 200 is implemented as a polarity (-60 kV to 0, 0 to +60 kV). 0V to +60kV is applied to the anode region rectifying part 310 , and -60kV to 0V is applied to the cathode region rectifying part 320 .

Therefore, in the prior art, in the case of a unipolar type X-ray tube, unipolar control was performed through a reference potential of 0V. In this case, the cost increase and quality margin due to the high load of the high-voltage component are reduced, and the circuit of the high-voltage X-ray generator 1000 is reduced. There is a problem in that loss due to high impedance increases.

However, in this embodiment, by setting the reference potential of the unipolar type X-ray tube so that the cathode 410 has the maximum value of the cathode voltage instead of 0V, the unipolar type cold cathode X-ray tube 400 which is the object of this embodiment is applied, yes For example, when 120 kV is applied, the high voltage is divided into the + region (0 to +60 kV) and the - region (0 to -60 kV) through the anode region rectifying part 310 and the cathode region rectifying part 320 and applied to the positive (0 to 60 kV) region. Bipolar) voltage supply and control is possible.

Accordingly, according to this embodiment, in spite of being a unipolar X-ray tube, it is possible to reduce costs and secure quality margins due to the load distribution effect of high-voltage components, and to reduce losses due to the minimization of the impedance of the circuit.

Therefore, it is possible to overcome the limitations of the above-described unipolar cold cathode X-ray tube 400 and to control polarity.

As described above, according to the present invention, the cathode of the X-ray tube is connected to a predetermined negative voltage so that the reference potential of the circuit has the maximum value of the predetermined negative voltage. A high-voltage X-ray generator capable of exhibiting the following effects is provided.

The use of all examples or exemplary terminology (eg, etc.) in the present invention is merely for the purpose of describing the present invention in detail, and unless defined by the claims, the scope of the present invention is limited by the examples or exemplary terminology. it's not going to be In addition, those skilled in the art can appreciate that various modifications, combinations and changes can be made according to design conditions and factors within the scope of the appended claims or equivalents thereof.

Therefore, the spirit of the present invention should not be limited to the above-described embodiments, and not only the claims described below, but also all ranges equivalent to or changed from these claims are within the scope of the spirit of the present invention. will be said to belong

1000: high voltage X-ray generator
100: power generator 110: external power
120: rectifier circuit 130: smoothing capacitor
140: inverter circuit 200: back pressure unit
300: rectifier 400: cold cathode X-ray tube
410: cathode 420: emitter
430: anode 440: target
450: gate electrode

Claims (4)

A field emission type high voltage X-ray generator including a cold cathode X-ray tube that is unipolar and cannot apply a center ground,
The cold cathode X-ray tube includes an anode and a cathode,
The cathode is connected to a predetermined cathode voltage, characterized in that the reference potential has a maximum value of the predetermined cathode voltage,
A rectifying unit including an anode region rectifying portion connected to the anode to supply a predetermined anode voltage and a cathode region rectifying portion connected to the cathode to supply a predetermined cathode voltage.
A high-voltage X-ray generator comprising a.
According to claim 1,
The high voltage X-ray generator,
a power generator including a power source and a plurality of switching elements;
and a back-pressure unit boosting the voltage supplied from the power generator.
The rectifying unit rectifies the voltage boosted from the back pressure unit,
The cold cathode X-ray tube is connected to the output terminal of the rectifier to generate X-rays.
High-voltage X-ray generator.
delete 3. The method of claim 2,
The positive electrode region rectifying portion and the cold electrode region rectifying portion are connected in parallel with the back pressure portion.
High-voltage X-ray generator.

Images