KR20190028279A - X-ray imaging device and driving method thereof - Google Patents

Abstract

The present invention relates to an X-ray imaging device capable of obtaining a clear image and a driving method thereof. More specifically, the X-ray imaging device comprises: an electron beam generating unit including a plurality of nano-emitters and cathodes; a first focusing electrode focusing an electron beam emitted from the electron beam generating unit; a deflector deflecting the electron beam focused at the first focusing electrode; a limiting electrode limiting the traveling of the electron beam deflected by the deflector; and an anode emitting an X-ray by irradiating the electron beam. The limiting electrode includes a limiting opening through which the electron beam may pass.

Description

X-RAY IMAGING DEVICE AND DRIVING METHOD THEREOF BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to an X-ray imaging apparatus and a driving method thereof. More particularly, the present invention relates to an x-ray imaging apparatus capable of acquiring a clear x-ray image and a driving method thereof.

A point electron source is an electron source whose electron flow starts at a point. In other words, the point electron source means an electron source in which an electron beam is generated in a very small area such as a point. When the electron beam is generated in a very small area such as a point, it is easy to concentrate the generated electron beam to a very small area again by using the electro-optical system, and there is an advantage that a minute probe beam can be relatively easily made . If the diameter of the electron beam is small, it can be very useful in various applications. For example, it is possible to improve the resolution of electron microscopes such as SEM and TEM, reduce the focal spot of the x-ray, and improve the resolution of the x-ray image.

An object of the present invention is to provide an X-ray imaging apparatus capable of acquiring a clear image while having a plurality of nanoemitters.

The present invention provides an electron beam apparatus including an electron beam generator including a plurality of nanoemitters and a cathode; A first focusing electrode for focusing the electron beam emitted from the electron beam generating unit; A deflector for deflecting the electron beam focused at the first focusing electrode; A limiting electrode that limits the traveling of the electron beam deflected by the deflector; And an anode radiating the electron beam to emit an x-ray, wherein the limiting electrode includes a limiting opening through which the electron beam can pass.

And a gate electrode for applying an electric field to the nanoemitters.

And an image acquisition unit for acquiring an x-ray image using the x-rays emitted from the anode.

The deflector may include electrodes spaced apart from each other with an electron beam path passing through the electron beam, and a voltage source for applying a voltage to the electrodes.

The deflector may include coils spaced apart from each other across an electron beam path through which the electron beam passes, and a current source providing current to the coils.

And a second focusing electrode for focusing the electron beam passing through the limiting opening.

The limiting electrode may further include an ammeter for measuring a current flowing through the limiting electrode.

The present invention provides a method of manufacturing a semiconductor device, comprising: an electron beam emitting step of emitting a plurality of electron beams in an electron beam generating part; An electron beam limiting step of limiting the traveling of the electron beams emitted from the electron beam generating part using a limiting electrode; And an anode irradiation step of irradiating at least a part of the electron beams to the anode, wherein the limiting electrode includes a limiting opening through which the electron beams can pass.

The electron beam limiting step may include passing one electron beam of the electron beams emitted from the electron beam generating section through the restriction opening.

The electron beam limiting step may include focusing the electron beams emitted from the electron beam generating unit using the first focusing electrode.

The electron beam limiting step may further include deflecting the focused electron beams at the first focusing electrode using a deflector.

The electron beam limiting step may further include obtaining a current intensity map of the limiting electrode by measuring a current flowing through the limiting electrode.

Condensing the electron beams may include determining whether the current intensity map is clear, and controlling the focusing of the electron beams by controlling the first focusing electrode.

Adjusting the focusing of the electron beams may include adjusting the focusing of the electron beams such that the planar area of the electron beams is at a minimum level at the same level as the lower surface of the confinement aperture.

The deflecting of the focused electron beams at the first focusing electrode may include controlling the deflector to correspond to the darkest spot in the current intensity map.

Controlling the deflector may include optimizing the magnitude of the voltage of the voltage source of the deflector.

Controlling the deflector may include optimizing the magnitude of the current of the current source of the deflector.

The step of irradiating the anode may include focusing the one electron beam using a second focusing electrode.

The x-ray imaging apparatus according to the present invention includes a deflector and a limiting opening, so that one of the electron beams generated from the plurality of nano-emitters can be irradiated to the anode with the largest current magnitude, .

1A and 1B are views for explaining the characteristics of an electron beam generated in a nano-emitter.
FIG. 2A is a view for explaining an X-ray imaging apparatus according to a comparative example of the present invention.
FIG. 2B is an enlarged view of region A of FIG. 2A.
FIG. 3 is an X-ray image obtained by the X-ray imaging apparatus according to FIGS. 2A and 2B.
4 is a view for explaining an X-ray imaging apparatus according to embodiments of the present invention,
5A and 5B are views for explaining embodiments of the deflector.
FIG. 6 is an X-ray image obtained by the X-ray imaging apparatus according to FIG.
7 is a diagram for explaining an intensity map of the current measured at the limiting electrode.
8A to 8C are views for explaining the shape of an electron beam passing through the confinement opening.
9A and 9B are actual images of the current intensity map of the limiting electrode.
10 is a flowchart illustrating a method of driving an X-ray imaging apparatus according to embodiments of the present invention.
11 is a view for explaining an X-ray imaging apparatus according to embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is to be understood that the terms 'comprises' and / or 'comprising' as used herein mean that an element, step, operation, and / or apparatus is referred to as being present in the presence of one or more other elements, Or additions.

Hereinafter, embodiments of the present invention will be described in detail.

1A and 1B are views for explaining the characteristics of an electron beam generated in a nano-emitter.

Referring to Figs. 1A and 1B, an electron beam apparatus including a cathode 11, first to fourth nanoemitters 13a to 13d on the cathode 11, and an anode fluorescent film 41 may be provided . Each of the first to fourth nanoemitters 13a to 13d may emit respective first to fourth electron beams 14a to 14d. The first to fourth electron beams 14a to 14b can be irradiated to the anode fluorescent film 41. [ The first to fourth electron beams 14a to 14d are irradiated to the anode fluorescent film 41 so that the first to fourth electron beam fluorescent points 42a to 42d are formed in the anode fluorescent film 41 have. The characteristics of the first to fourth electron beams 14a to 14d can be grasped by observing the first to fourth electron beam fluorescent points 42a to 42d. Each of the first to fourth electron beam fluorescent points 42a to 42d may be formed to correspond to a focal spot of each of the first to fourth electron beams 14a to 14d. The focal spot may refer to a planar area of each of the first to fourth electron beams 14a to 14d irradiated on the anode fluorescent film 41 on the surface of the anode fluorescent film 41. [ In other words, the focal spot may mean the planar area of the electron beam at the surface of the object to which the electron beam is irradiated.

The larger the voltage difference between the anode fluorescent film 41 and the cathode 11, the smaller the diameter of each of the first to fourth electron beam fluorescent points 42a to 42d can be. In other words, as the voltage difference between the anode fluorescent film 41 and the cathode 11 increases, the focal spots of the first through fourth electron beams 14a-14d irradiated to the anode fluorescent film 41 become smaller Can be. The diameter of each of the first to fourth electron beam fluorescent points 42a to 42d can be increased as the distance between the anode fluorescent film 41 and the cathode 11 is increased. The distance between the first to fourth electron beam fluorescent points 42a to 42d may be increased as the distance between the anode fluorescent film 41 and the cathode 11 is increased.

FIG. 2A is a view for explaining an X-ray imaging apparatus according to a comparative example of the present invention, and FIG. 2B is an enlarged view of a region A in FIG. 2A.

2A and 2B, the X-ray imaging apparatus may include an electron beam generating unit 10, a gate electrode 20, a focusing electrode 30, an anode 40, and an image acquiring unit 50.

The electron beam generating portion 10 may include a cathode 11, an adhesive layer 12, and first to fourth nanoemitters 13a to 13d.

First to fourth nanoemitters 13a-13d may be provided on the cathode 11. [ Although the number of the nanoemitters 13a-13d is four, it is not limited thereto. The cathode 11 may be grounded. The first to fourth nano-emitters 13a-13d may be attached on the cathode 11 by an adhesive layer 12. The first to fourth nanoemitters 13a to 13d and the adhesive layer 12 may be attached to the cathode 11 through a paste printing process. The first to fourth nanoemitters 13a to 13d may be spaced apart from each other in a plan view. The shortest distance between the first to fourth nanoemitters 13a to 13d may be 1 to 200 mu m. The first to fourth nano-emitters 13a to 13d may include a conductive material. For example, each of the first to fourth nanoemitters 13a to 13d may include carbon nanotubes (CNTs). The lengths of the first through fourth nanoemitters 13a-13d may be different from each other. The angle formed by each of the first to fourth nanoemitters 13a to 13d with the upper surface of the cathode 11 may be different from each other. In other words, the degree of inclination of each of the first to fourth nanoemitters 13a to 13d may be different from each other.

The adhesive layer 12 may comprise an adhesive material. For example, the adhesive layer 12 may include a conductive paste.

A gate electrode 20 may be provided on the electron beam generating portion 10. In other words, the gate electrode 20 can be provided between the electron beam generating portion 10 and the anode 40. [ A positive voltage may be applied to the gate electrode 20. [ The gate electrode 20 may comprise a gate opening 21. The diameter of the gate opening 21 may be between 1 [mu] m and 500 [mu] m. The shortest distance between the gate electrode 20 and the electron beam generating portion 10 may be 1 占 퐉 to 5000 占 퐉. The shortest distance between the gate electrode 20 and the electron beam generating portion 10 may be 0.1 to 10 times the diameter of the gate opening 21. [

The focusing electrode 30 may be provided on the gate electrode 20. In other words, the focusing electrode 30 may be provided between the gate electrode 20 and the anode 40. However, the position of the focusing electrode 30 may not be limited thereto. A positive voltage may be applied to the focusing electrode 30. [ The focusing electrode 30 may include a focusing aperture 31. Instead of the focusing electrode 30, an optical system (for example, an electrostatic lens or a magnetic lens) capable of focusing the electron beam may be provided.

An anode 40 may be provided on the focusing electrode 30. In other words, the anode 40 may be provided between the focusing electrode 30 and the image acquiring unit 50. A positive voltage may be applied to the anode 40. [ The anode 40 may include an anode target and an anode electrode. The anode target may include a substance that emits x-rays in response to electron beam irradiation. As an example, the anode target may comprise tungsten or molybdenum. The anode electrode may comprise a material having a high electrical conductivity. In one example, the anode electrode may comprise copper.

An image acquisition unit 50 may be provided on the anode 40. [ The image acquisition unit 50 may acquire an x-ray image using the x-rays emitted from the anode 40. [

A positive voltage may be applied to the gate electrode 20 to cause a voltage difference between the gate electrode 20 and the cathode 11. The voltage difference between the gate electrode 20 and the cathode 11 causes the first to fourth electron beams 14a to 14d to be emitted from the respective first to fourth nanoemitters 13a to 13a . The first to fourth electron beams 14a to 14d may be emitted at the ends of each of the first to fourth nanoemitters 13a to 13d. The length of the first nanoemitter 13a among the first to fourth nanoemitters 13a to 13d may be the longest and the length of the fourth nanoemitter 13d may be the shortest. The longer the length of the nano-emitters 13a-13d, the smaller the voltage difference between the cathode 11 and the gate electrode 20 where the electron beams 14a-14d begin to emit. In other words, the voltage difference between the gate electrode 20 and the cathode 11 at which the first electron beam 14a starts to be emitted from the first nanoemitter 13a is the voltage difference between the fourth nanoemitter 13d and the fourth electron beam 14b, May be smaller than the voltage difference between the gate electrode 20 and the cathode 11 from which the cathode 14d begins to emit. The smaller the diameter of the nano-emitters 13a-13d, the smaller the planar area of the emitted electron beams 14a-14d.

A positive voltage may be applied to the anode 40 to cause a voltage difference between the anode 40 and the cathode 11. [ The first to fourth electron beams 14a to 14d emitted from the nanoemitters 13a to 13d are accelerated by the voltage difference between the anode 40 and the cathode 11 and can proceed in the direction of the anode 40 have. The traveling path of each of the first to fourth electron beams 14a to 14d may be different from each other. In other words, the paths through which the first to fourth electron beams 14a to 14d are emitted from the nano-emitters 13a to 13d to reach the anode 40 may be different from each other. Part of the first to fourth electron beams 14a to 14d may overlap with each other while the other part does not overlap with each other as it proceeds in the direction of the anode 40. [

The first to fourth electron beams 14a to 14d can pass through the gate opening 21 of the gate electrode 20. [ The gate opening 21 may have a size sufficient for the first to fourth electron beams 14a to 14d to pass through.

The first to fourth electron beams 14a to 14d passing through the gate opening 21 can pass through the converging opening 31 of the focusing electrode 30. [ The focusing aperture 31 may have a size sufficient for the first to fourth electron beams 14a to 14d to pass through. While passing through the focusing aperture 31, the first through fourth electron beams 14a-14d may be focused. It is possible to control the focusing so that the focal spots of the first to fourth electron beams 14a to 14d are minimized at the surface of the anode 40 by controlling the first focusing electrode 30. [

The first through fourth electron beams 14a through 14d that have passed through the converging opening 31 can be irradiated to the anode 40. [ Each of the first to fourth electron beams 14a to 14d may be irradiated to the anode 40 at different positions. In other words, on the surface of the anode 40, the focal spots of each of the first through fourth electron beams 14a-14d may be spaced from each other. The first to fourth electron beams 14a to 14d may be irradiated to the anode 40 so that the first to fourth X-rays 43a to 43d may be emitted from the anode 40. [ Each of the first to fourth X-rays 43a to 43d may be emitted from the anode 40 at different positions. In other words, at the surface of the anode 40, the emission points of the first to fourth X-rays 43a to 43d may be spaced apart from each other.

The first to fourth X-rays 43a to 43d may travel from the anode 40 toward the image acquisition unit 50. As the emission points of the first to fourth X-rays 43a to 43d are spaced apart from each other, the progressing paths of the first to fourth X-rays 43a to 43d, respectively, can be different. In other words, some of the first to fourth X-rays 43a to 43d may overlap each other, and the other portions may not overlap with each other. The first to fourth X-rays 43a to 43d may be irradiated to the subject SJ disposed between the anode 40 and the image acquiring unit 50. [

The first to fourth X-rays 43a to 43d may be irradiated to the image acquiring unit 50. FIG. The image acquiring unit 50 can acquire an X-ray image of the subject SJ. The x-ray image obtained by the first to fourth X-ray lines 43a to 43d having the emission points spaced from each other may not be clear. In other words, since the x-ray image is acquired by the plurality of x-rays 43a-43d, the x-ray image may include a plurality of images overlapping each other.

FIG. 3 is an X-ray image obtained by the X-ray imaging apparatus according to FIGS. 2A and 2B.

Referring to FIG. 3, it can be seen that the subject appears unclear in an X-ray image obtained by a plurality of X-rays.

FIG. 4 is a view for explaining an X-ray imaging apparatus according to embodiments of the present invention, and FIGS. 5A and 5B are views for explaining embodiments of a deflector. The same reference numerals are used for the same constituent elements described with reference to FIGS. 2A and 2B, and a duplicate description will be omitted.

4, 5A and 5B, an X-ray imaging apparatus includes an electron beam generating unit 10, a gate electrode 20, a first focusing electrode 30, an anode 40, an image acquiring unit 50, A deflector 60, a limiting electrode 70, and a second focusing electrode 80, as shown in FIG.

The deflector (60) may be provided on the first focusing electrode (30). In other words, the deflector 60 may be provided between the first focusing electrode 30 and the anode 40. However, the position of the deflector 60 may not be limited thereto. The deflector 60 may be located between the first focusing electrode 30 and the gate electrode 20 or between the gate electrode 20 and the cathode 11 (see FIG. 2B). In one embodiment, the deflector 60 may be an electrostatic deflector (see FIG. 5A). The deflector 60 may include X-axis electrodes 61a, Y-axis electrodes 61b, an X-axis voltage source 62a, and a Y-axis voltage source 62b. The electron beam path 65 can be defined by the X-axis electrodes 61a and the Y-axis electrodes 61b. The X-axis electrodes 61a may be provided on both sides of the electron beam path 65 along the X-axis. The Y-axis electrodes 61b may be provided on both sides of the electron beam path 65 along the Y-axis. A voltage difference may be generated between the X-axis electrodes 61a by applying a voltage to the X-axis electrodes 61a by the X-axis voltage source 62a. Accordingly, an electric field can be generated along the X-axis in the electron beam path 65 between the X-axis electrodes 61a. The Y-axis voltage source 62b applies a voltage to the Y-axis electrodes 61b so that a voltage difference may occur between the Y-axis electrodes 61b. Thus, an electric field can be generated along the Y axis in the electron beam path 65 between the Y-axis electrodes 61b. The electron beam passing through the electron beam path 65 can be deflected by an electric field generated along the X and Y axes. The voltage applied by the X-axis voltage source 62a can be defined as the X voltage, and the voltage applied by the Y-axis voltage source 62b can be defined as the Y voltage.

In another embodiment, the deflector 60 may be a magnetic elongated deflector (see FIG. 5B). The deflector 60 may include X-axis coils 63a, Y-axis coils 63b, an X-axis current source 64a, and a Y-axis current source 64b. The electron beam path 65 can be defined by the X-axis coils 63a and the Y-axis coils 63b. X-axis coils 63a may be provided on both sides of the electron beam path 65 along the X-axis. Y-axis coils 63b may be provided on both sides of the electron beam path 65 along the Y-axis. The X-axis current source 64a provides a current to the X-axis coils 63a so that a magnetic field can be generated in the X-axis coils 63a. The Y-axis current source 64b provides a current to the Y-axis coils 63b so that a magnetic field can be generated in the Y-axis coils 63b. The magnetic field may pass through the electron beam path 65. By the magnetic field generated in the X-axis coils 63a and the Y-axis coils 63b, the electron beam passing through the electron beam path 65 can be deflected. The current provided by the X-axis current source 64a can be defined as the X current, and the current provided by the Y-axis current source 64b can be defined as the Y current.

A limiting electrode (70) may be provided on the deflector (60). In other words, the limiting electrode 70 may be provided between the deflector 60 and the anode 40. A positive voltage may be applied to the limiting electrode 70. The limiting electrode (70) may include a limiting opening (71). The diameter of the limiting opening 71 may be between 1 [mu] m and 2000 [mu] m. The shortest distance between the electron beam generating portion 10 and the limiting electrode 70 may be 0.1 mm to 200 mm. The diameter of the limiting opening 71 can be appropriately determined according to the shortest distance between the electron beam generating portion 10 and the limiting electrode 70. [ For example, when the shortest distance between the electron beam generating portion 10 and the limiting electrode 70 is 200 mm, the diameter of the limiting opening 71 may be 2000 탆. For another example, when the shortest distance between the electron beam generating portion 10 and the limiting electrode 70 is 0.1 mm, the diameter of the limiting opening 71 may be 1 탆. The limiting electrode 70 may include a lower surface 72 facing the cathode 11. An ammeter 73 may be connected to the limiting electrode 70. The limiting electrode 70 may comprise tungsten or molybdenum.

The second focusing electrode 80 may be provided on the limiting electrode 70. In other words, the second focusing electrode 80 may be provided between the limiting electrode 70 and the anode 40. Positive voltage may be applied to the second focusing electrode 80. [ The second focusing electrode 80 may include a second focusing electrode opening 81.

The driving method of the X-ray imaging apparatus will now be described in which the first to fourth electron beams 14a to 14d are emitted from the first to fourth nanoemitters 13a to 13d (see FIG. 2B) on the cathode 11 .

The first to fourth electron beams 14a to 14d emitted from the first to fourth nanoemitters 13a to 13d are accelerated by the voltage difference between the anode 40 and the cathode 11, ) Direction. The traveling path of each of the first to fourth electron beams 14a to 14d may be different from each other.

The first to fourth electron beams 14a to 14d can pass through the gate opening 21 of the gate electrode 20. [

The first to fourth electron beams 14a to 14d passing through the gate opening 21 can pass through the first focusing opening 31 of the first focusing electrode 30. [ While passing through the first focusing aperture 31, the first through fourth electron beams 14a-14d can be focused.

The first through fourth electron beams 14a through 14d that have passed through the first converging aperture 31 can pass through the electron beam path 65 defined by the deflector 60. [ As it passes through the electron beam path 65, the first through fourth electron beams 14a-14d may be deflected along the X and Y axes (Figs. 5A and 5B). When the deflector 60 is an electrostatic deflector (Fig. 5A), the first to fourth electron beams 14a to 14d passing through the electron beam path 65 by the electric field generated in the electron beam path 65 are deflected . When the deflector 60 is a magnetic elongated deflector (Fig. 5B), the first through fourth electron beams 14a-14d passing through the electron beam path 65 by the magnetic field passing through the electron beam path 65 can be deflected have. The deflector 60 can be controlled to adjust the deflection of the first to fourth electron beams 14a to 14d.

The limiting electrode 70 may limit the progress of the first to fourth electron beams 14a to 14d. Only one of the first to fourth electron beams 14a to 14d that have passed through the electron beam path 65 can pass through the limiting opening 71 of the limiting electrode 70. [ In one example, the second electron beam 14b may pass through the limiting opening 71. [ One of the first, third and fourth electron beams 14a, 14c, 14d may pass through the limiting aperture 71, although the second electron beam 14b is shown passing through the limiting aperture 71. [ The limiting opening 71 may have an appropriate size so that only one electron beam can pass through it. According to the deflection of the first to fourth electron beams 14a to 14d by the deflector 60, the electron beam passing through the limiting opening 71 can be determined. All of the first to fourth electron beams 14a to 14d may not pass through the limiting opening 71 in accordance with the deflection of the first to fourth electron beams 14a to 14d by the deflector 60. [

 The first, third and fourth electron beams 14a, 14c and 14d can be irradiated onto the lower surface 72 of the limiting electrode 70 when the second electron beam 14b passes through the limiting opening 71 have. Current can flow through the limiting electrode 70 by the first, third, and fourth electron beams 14a, 14c, and 14d irradiated to the lower surface 72 of the limiting electrode 70. [ The current flowing from the ammeter 73 of the limiting electrode 70 to the limiting electrode 70 can be measured.

The second electron beam 14b having passed through the limiting opening 71 can pass through the second focusing opening 81 of the second focusing electrode 80. [ While passing through the second focusing aperture 81, the second electron beam 14b can be focused. The focus can be controlled so as to minimize the focal spot of the second electron beam 14b at the surface of the anode 40 by controlling the second focusing electrode 80. [

And the second electron beam 14b having passed through the second converging opening 81 can be irradiated to the anode 40. [ The second electron beam 14b may be irradiated to the anode 40 and the X-ray 43 may be emitted from the anode 40. The X-ray 43 may travel from the anode 40 toward the image acquisition unit 50. The X-ray 43 may be irradiated on the subject SJ disposed between the anode 40 and the image acquisition unit 50. [

And the X-ray 43 may be irradiated to the image acquiring unit 50. The image acquiring unit 50 can acquire an X-ray image of the subject SJ. Since the x-ray image is acquired by one x-ray 43, the x-ray image of the subject SJ can be sharpened.

The larger the magnitude of the current of the second electron beam 14b that has passed through the limiting aperture 71, the more clear the x-ray image can be obtained.

FIG. 6 is an X-ray image obtained by the X-ray imaging apparatus according to FIG.

Referring to FIG. 6, it can be seen that the subject appears clearly in the X-ray image obtained by one X-ray.

7 is a diagram for explaining an intensity map of the current measured at the limiting electrode.

Referring to FIGS. 4, 5A, 5B, and 7, an ammeter 73 connected to the limiting electrode 70 can be used to obtain a current intensity map of the current flowing through the limiting electrode 70. The current intensity map may be obtained on the basis of an electrostatic deflector (Fig. 5A) or a magnetic elongated deflector (Fig. 5B). In the following description, the case where the electrostatic type deflector is used as a reference (Fig. 5A) will be described by way of example. The case where the magnetic elongated deflector is used as a reference (Fig. 5B) can also be similar to the following description.

The current intensity map may comprise a plurality of pixels. The magnitude of the X voltage of the deflector 60 can be displayed on the X axis of the current intensity map and the magnitude of the Y voltage of the deflector 60 can be displayed on the Y axis of the current intensity map. Each pixel may have a magnitude of the X voltage and a magnitude of the Y voltage corresponding thereto. For example, the magnitude of the X voltage corresponding to the first pixel P1 is X1, and the magnitude of the Y voltage is Y1. As another example, the magnitude of the X voltage corresponding to the second pixel P2 is X2, and the magnitude of the Y voltage is Y2. In other words, when the magnitude of the X voltage of the deflector 60 is X1 and the magnitude of the Y voltage is Y1, the intensity of the current flowing through the limiting electrode 70 may appear in the first pixel P1 of the current intensity map have. When the magnitude of the X voltage of the deflector 60 is X2 and the magnitude of the Y voltage is Y2, the intensity of the current flowing through the limiting electrode 70 may appear in the second pixel P2 of the current intensity map. As described above, the current intensity map can show the intensity of the current flowing through the limiting electrode 70 in accordance with the magnitude of the X voltage and the magnitude of the Y voltage of the deflector 60.

In the current intensity map, the greater the intensity of the current flowing through the limiting electrode 70, the brighter the brightness of each pixel can be. When the first pixel P1 and the second pixel P2 are compared, the brightness of the first pixel P1 is brighter than the brightness of the second pixel P2, so that the X voltage of the deflector 60 is X2 The intensity of the current flowing through the limiting electrode 70 may be larger when the X voltage of the deflector 60 is X1 and the Y voltage is Y1 than when the Y voltage is Y2.

 Obtaining the current intensity map may be performed by varying the X voltage magnitude and the Y voltage magnitude of the deflector 60 within a certain range and by varying the X voltage magnitude and the Y voltage magnitude within the range, And measuring the intensity of the current to indicate the brightness of the pixels of the current intensity map.

As shown in FIG. 4, when the first to fourth electron beams 14a to 14d are emitted from the first to fourth nanoemitters 13a to 13d, the first to fourth spots SP1 to SP4 And the peripheral region AR may be formed. Each of the first to fourth spots (SP1 to SP4) and the peripheral area (AR) may be formed by collecting pixels having the same brightness. The first to fourth spots SP1 to SP4 may be relatively dark compared to the surrounding area AR. The second spot SP2 may be brighter than the first spot SP1 and the third spot SP3 may be brighter than the second spot SP2 and the fourth spot SP4 may be brighter than the third spot SP3. It can be bright.

When the deflector 60 has the X voltage and the Y voltage corresponding to the pixels located in the first spot SP1, the electron beam having the largest electric current among the first to fourth electron beams 14a to 14d Can pass through the restriction opening 71.

When the deflector 60 has the X voltage and the Y voltage corresponding to the pixels located in the second spot SP2, the magnitude of the current among the first through fourth electron beams 14a through 14d is the second largest The electron beam can pass through the limiting opening 71.

When the deflector 60 has the X voltage and the Y voltage corresponding to the pixels positioned in the fourth spot SP4, the electron beam having the smallest current magnitude among the first through fourth electron beams 14a through 14d Can pass through the restriction opening 71.

When the deflector 60 has the X voltage and the Y voltage corresponding to the pixels located in the peripheral region AR, all of the first to fourth electron beams 14a to 14d do not pass through the limiting opening 71 .

By checking the current intensity map and controlling the deflector 60 such that the magnitudes of the X and Y voltages of the deflector 60 correspond to the pixels in the first spot SP1, 14a-14d, the electron beam having the largest current can pass through the limiting opening 71. [

In the current intensity map, the first to fourth spots SP 1 to SP 4 may reflect the shape of the limiting opening 71. In other words, when the restriction opening 71 is planarly circular, the first to fourth spots SP1 to SP4 can be formed in a circular shape, and when the restriction opening 71 is rectangular in plan view, And the fourth spots SP1 to SP4 may be formed in a square shape.

8A to 8C are views for explaining the shape of an electron beam passing through the confinement opening.

Referring to FIGS. 4, 7 and 8A, the electron beam 14 is focused at the same level as the lower surface 72 of the limiting electrode 70 in accordance with the focusing of the first focusing electrode 30, . In other words, it can be focused so that the focus is formed at the same level as the lower surface 72 of the limiting electrode 70. In this case, the first to fourth spots (SP1 to SP4) can be relatively clearly formed in the current intensity map of Fig. The focusing of the electron beam 14 can be controlled so that the planar area of the electron beam 14 is minimized at the same level as the lower surface 72 of the limiting opening 71 by controlling the first focusing electrode 30. [ The sharpness of the current intensity map can be confirmed and the electron beam 14 can be confirmed to have a minimum planar area at the same level as the lower surface 72 of the limiting opening 71.

4 and 8B, according to the focusing of the first focusing electrode 30, the electron beam 14 can propagate in a state of passing through the limiting opening 71 of the limiting electrode 70 and diverging. In other words, as the electron beam 14 advances in the limiting opening 71, its planar area can gradually increase. The electron beam 14 can collide with the upper sidewalls 74a of the limiting opening 71. [ X-rays can be generated in the upper sidewalls 74a of the limiting opening 71 by the electron beam 14. [ X-rays generated in the upper sidewalls 74a of the limiting opening 71 can travel in the direction of the anode 40. [ The X-rays may be irradiated to the subject SJ and the image acquiring unit 50. By the X-rays, the sharpness of the X-ray image acquired by the image acquiring unit 50 can be reduced.

4 and 8C, according to the focusing of the first focusing electrode 30, the electron beam 14 may converge while passing through the limiting opening 71 of the limiting electrode 70. In other words, as the electron beam 14 advances in the limiting opening 71, its planar area can be gradually reduced. The electron beam 14 can collide with the lower surface 72 of the limiting opening 71. [ X-rays can be generated on the lower surface 72 of the limiting opening 71 by the electron beam 14. The x-rays are limited by the limiting aperture 71, and may not advance in the direction of the anode 40.

9A and 9B are actual images of the current intensity map of the limiting electrode.

9A and 9B, in the current intensity map of FIG. 9A, it can be seen that spots in which relatively dark pixels are gathered are distinguishable from other parts, and in FIG. 9B, spots are formed to be distinguishable from other parts . As shown in FIG. 8A, when the planar area of the electron beam becomes minimum at the same level as the lower surface of the limiting opening, a current intensity map as shown in FIG. 9A can be obtained. 8A, when the planar area of the electron beam is larger than the diameter of the limiting opening at the same level as the lower surface of the limiting opening, a current intensity map as shown in Fig. 9B can be obtained. The smaller the planar area of the electron beam at the same level as the lower surface of the limiting opening, the better the sharpness of the current intensity map can be.

10 is a flowchart illustrating a method of driving an X-ray imaging apparatus according to embodiments of the present invention.

4 and 10, a voltage may be applied to the gate electrode 20 to emit the first to fourth electron beams 14a to 14d from the first to fourth nanoemitters 13a to 13d , The first to fourth electron beams 14a to 14d may be accelerated by applying a voltage to the anode 40 (S1).

A voltage may be applied to the first focusing electrode 30 to focus the first through fourth electron beams 14a-14d (S2).

The current intensity map flowing through the limiting electrode 70 can be obtained by the first to fourth electron beams 14a to 14d by using the deflector 60 and the ammeter 73 (S3).

It is determined whether or not the spots of the current intensity map are clear (S4). If the spots of the current intensity map are acquired unclearly, the first focusing electrode 30 is controlled to detect the spots of the first to fourth electron beams 14a- The focusing can be adjusted (S5). Adjusting the focusing may include allowing the electron beam passing through the limiting aperture 71 to have a minimum planar area at the same level as the lower surface 72 of the limiting aperture 71. The convergence of the first to fourth electron beams 14a to 14d is adjusted and the first to fourth electron beams 14a to 14d are used to adjust the convergence of the limiting electrodes 70a to 70d by using the deflector 60 and the ammeter 73, (S3). ≪ / RTI > The above process can be repeated until the spots in the current intensity map are clear.

It is determined whether or not the spots of the current intensity map are clear (S4). If the spots of the current intensity map are clearly obtained, the current intensity map can be used to optimize the deflection of the first to fourth electron beams 14a to 14d (S6). The deflection optimization includes identifying the darkest spots in the current intensity map and controlling the deflection of the first through fourth electron beams 14a-14d by controlling the deflector 60 to correspond to the darkest spots . The voltage applied by the X-axis voltage source 62a and the Y-axis voltage source 62b can be optimized when the deflector 60 is an electrostatic deflector (Fig. 5A) (Fig. 5B), the magnitude of the current provided by the X-axis current source 64a and the Y-axis current source 64b can be optimized. According to the deflection optimization, the electron beam having the largest current value among the first to fourth electron beams 14a to 14d can pass through the limiting opening 71. [

The convergence of the electron beam passing through the confinement opening 71 can be controlled by controlling the second focusing electrode 80 (S7). Thus, the focal spot of the electron beam passing through the limiting opening 71 can be focused so as to be minimum at the surface of the anode 40.

11 is a view for explaining an X-ray imaging apparatus according to embodiments of the present invention. The same reference numerals are used for the same constituent elements described with reference to FIG. 4, and redundant explanations will be omitted.

Referring to FIG. 11, a negative voltage may be applied to the cathode 11, and the anode 40 may be grounded. Although the limiting electrode 70 is shown as being grounded, negative or positive voltage may be applied.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood. It is therefore to be understood that the above-described embodiments are illustrative and not restrictive in every respect.

10: electron beam generator
20: gate electrode
30: first focusing electrode
40:
50:
60: Deflector
70:
80: second focusing electrode

Claims (18)

An electron beam generator including a plurality of nanoemitters and a cathode;
A first focusing electrode for focusing the electron beam emitted from the electron beam generating unit;
A deflector for deflecting the electron beam focused at the first focusing electrode;
A limiting electrode that limits the traveling of the electron beam deflected by the deflector; And
And an anode for irradiating the electron beam to emit an X-ray,
Wherein the limiting electrode comprises a limiting aperture through which the electron beam can pass.
The method according to claim 1,
And a gate electrode for applying an electric field to the nanoemitters.
The method according to claim 1,
And an image acquisition unit for acquiring an x-ray image using an x-ray emitted from the anode.
The method according to claim 1,
The deflector includes electrodes spaced apart from each other with an electron beam path passing through the electron beam,
And a voltage source for applying a voltage to the electrodes.
The method according to claim 1,
Wherein the deflector comprises coils spaced apart from each other across the electron beam path through which the electron beam passes,
And a current source providing current to the coils.
The method according to claim 1,
And a second focusing electrode for focusing the electron beam passing through the limiting opening.
The method according to claim 1,
Wherein the limiting electrode further comprises an ammeter for measuring a current flowing in the limiting electrode.
An electron beam emitting step of emitting a plurality of electron beams from the electron beam generating part;
An electron beam limiting step of limiting the traveling of the electron beams emitted from the electron beam generating part using a limiting electrode; And
And an anode irradiation step of irradiating at least a part of the electron beams to an anode,
Wherein the limiting electrode includes a limiting opening through which the electron beams can pass.
9. The method of claim 8,
The electron beam limiting step includes:
Wherein one of the electron beams emitted from the electron beam generating unit passes through the restriction opening.
9. The method of claim 8,
The electron beam limiting step includes:
And focusing the electron beams emitted from the electron beam generating unit using a first focusing electrode.
11. The method of claim 10,
The electron beam limiting step includes:
And deflecting the focused electron beams at the first focusing electrode using a deflector.
12. The method of claim 11,
The electron beam limiting step includes:
And measuring a current flowing through the limiting electrode to obtain a current intensity map of the limiting electrode.
13. The method of claim 12,
Condensing the electron beams may include,
Determining whether the current intensity map is clear, and controlling the convergence of the electron beams by controlling the first focusing electrode.
14. The method of claim 13,
Adjusting the focusing of the electron beams may include:
And adjusting convergence of the electron beams so that the planar area of the electron beams is minimized at the same level as the lower surface of the confinement opening.
13. The method of claim 12,
The deflecting of the focused electron beams at the first focusing electrode,
And controlling the deflector to correspond to the darkest spot in the current intensity map.
16. The method of claim 15,
Controlling the deflector comprises:
And optimizing the magnitude of the voltage of the voltage source of the deflector.
16. The method of claim 15,
Controlling the deflector comprises:
And optimizing a magnitude of a current of the current source of the deflector.
10. The method of claim 9,
The method of claim 1,
And focusing the one electron beam using a second focus electrode.

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