X-ray generator and X-ray imaging device

Abstract

The X-ray generating device includes an X-ray generating tube having an insulating tube having a first open end and a second open end, a cathode including an electron emitting portion arranged to close the first open end of the insulating tube, and an anode including a target that generates X-rays when electrons from the electron emitting portion collide with the target, a drive circuit that drives the X-ray generating tube, and a container that houses the X-ray generating tube and the drive circuit, the container having a third open end, the X-ray generating tube having a cathode arranged to close the first open end of the insulating tube and an anode including a target that generates X-rays when electrons from the electron emitting portion collide with the target, the drive circuit that drives the X-ray generating tube, and a container that houses the X-ray generating tube and the drive circuit, the container having a third open end, the X-ray generating tube having a cathode arranged to close the third open end, an insulating liquid is filled in the storage container, the storage container defines a first space that stores the drive circuit and a second space that protrudes from the first space and stores the X-ray generating tube, the storage container includes a protrusion that surrounds the second space, one end of the second space constitutes the third opening end, an outer surface of the cathode has a cylindrical side, the side of the cathode is surrounded by a first member, and the first member is surrounded by a second member arranged between the first member and the storage container.

Description

[Technical field]

[0001] The present invention relates to an X-ray generating device and an X-ray imaging device. [Background technology]

[0002] Patent Document 1 describes an X-ray generating device that includes an X-ray generating tube, a tube drive circuit that drives the X-ray generating tube, and a container that houses the X-ray generating tube and the tube drive circuit. The container is filled with an insulating liquid that ensures insulation between the X-ray generating tube and the tube drive circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-103451 A Summary of the Invention

[0004] When an X-ray generating device is used for a long period of time, an abnormal discharge may occur in the X-ray generating tube. The inventor's research has revealed that an abnormal discharge occurs between the cathode and anode of the X-ray generating tube through the outer surface of the insulating tube. The abnormal discharge may cause the X-ray generating device to stop or break down.

[0005] One aspect of the present invention provides an advantageous technique for suppressing the occurrence of abnormal discharge in an X-ray generating device.

[0006] A first aspect of the present invention relates to an X-ray generating device, the X-ray generating device comprising: an X-ray generating tube having an insulating tube having a first open end and a second open end; a cathode arranged to close the first open end of the insulating tube and including an electron emitting portion; and an anode arranged to close the second open end and including a target that generates X-rays when electrons from the electron emitting portion collide with the target; a drive circuit that drives the X-ray generating tube; and a container that contains the X-ray generating tube and the drive circuit, the container having a third open end, is arranged to close the third opening end, and an insulating liquid is filled in the storage container, and the storage container defines a first space that stores the drive circuit and a second space that protrudes from the first space and stores the X-ray generating tube, the storage container includes a protrusion that surrounds the second space, one end of the second space constitutes the third opening end, an outer surface of the cathode has a cylindrical side surface, the side surface of the cathode is surrounded by a first member, and the first member is surrounded by a second member arranged between the first member and the storage container.

[0007] A second aspect of the present invention relates to an X-ray generating device, the X-ray generating device comprising: an X-ray generating tube having an insulating tube having a first opening end and a second opening end; a cathode arranged to close the first opening end of the insulating tube and including an electron emitting portion; and an anode arranged to close the second opening end and including a target that generates X-rays when electrons from the electron emitting portion collide with the target; a drive circuit that drives the X-ray generating tube; and a container that houses the X-ray generating tube and the drive circuit, the container having a third opening end, the X-ray generating tube arranged to close the third opening end, the container being filled with an insulating liquid, and the container housing the drive circuit. the housing container includes a protrusion that surrounds the second space, one end of the second space constitutes the third opening end, a side of the cathode is surrounded by a member arranged between the cathode and the housing container, the housing container has a convex portion that protrudes toward the inside of the housing container in a cross section including the axis of the X-ray generating tube, the member has a first region that overlaps with a virtual line connecting the convex portion and an outer surface of the cathode and a second region that is closer to the anode than the first region, and a maximum thickness of the member in the first region is greater than a maximum thickness of the member in the second region.

[0008] A third aspect of the present invention relates to an X-ray imaging device, the X-ray imaging device comprising an X-ray generator according to the first or second aspect, and an X-ray detector that detects X-rays emitted from the X-ray generator. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a conventional X-ray generating device, for explaining the basic configuration of an X-ray generating device according to the present disclosure. [Diagram 2] FIG. 1 is a diagram exemplarily and diagrammatically illustrating the configuration of an X-ray generating device according to a first embodiment. [Diagram 3] FIG. 10 is a diagram exemplarily and diagrammatically illustrating the configuration of an X-ray generating device according to a second embodiment. [Figure 4]FIG. 11 is a diagram exemplarily and diagrammatically illustrating the configuration of an X-ray generating device according to a third embodiment. [Diagram 5] FIG. 13 is a diagram exemplarily and diagrammatically illustrating the configuration of an X-ray generating device according to a fourth embodiment. [Figure 6] FIG. 4 is a diagram showing the occurrence of abnormal discharge. [Figure 7] FIG. 1 is a diagram illustrating a triboelectric series in frictional electrification with an insulating liquid. [Figure 8] FIG. 13 is a diagram exemplarily and diagrammatically illustrating the configuration of an X-ray generating device according to a fifth embodiment. [Figure 9] FIG. 13 is a diagram illustrating a configuration of a first modified example of the X-ray generating device according to the fifth embodiment. [Figure 10] FIG. 13 is a diagram illustrating a configuration of a second modified example of the X-ray generation device according to the fifth embodiment. [Figure 11] FIG. 13 is a diagram illustrating a configuration of a third modified example of the X-ray generating device according to the fifth embodiment. [Figure 12] FIG. 13 is a diagram illustrating a configuration of a fourth modified example of the X-ray generator according to the fifth embodiment. [Figure 13] FIG. 1 is a diagram showing the configuration of an X-ray imaging apparatus according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] First, a basic configuration of an X-ray generating device 100 in the present disclosure will be described with reference to FIG. 1. The X-ray generating device 100 may include an X-ray generating tube 1 and a container 50 that contains the X-ray generating tube 1. The X-ray generating device 100 may further include a driving circuit 40 that drives the X-ray generating tube 1, and the driving circuit 40 may be contained in the container 50 and connected to the X-ray generating tube 1 via a cable 42. A part of the X-ray generating tube 1 (an anode 20 described later) may be exposed to the external space of the container 50 (the external space of the X-ray generating device 100). An insulating liquid 60 is filled in the internal space of the container 50. In another respect, the internal space of the container 50 is filled with the insulating liquid 60, except for the space occupied by the components (X-ray generating tube 1, cable 42, etc.) contained in the container 50. The insulating liquid 60 may be, for example, an insulating oil such as a mineral oil or a chemically synthesized oil. Alternatively, the insulating liquid 60 may be a liquid other than insulating oil, for example, a fluorine-based inert liquid (for example, Fluorinert (trademark)).

[0012] The X-ray generating tube 1 may include an insulating tube 10, a cathode 30, and an anode 20. The internal space of the X-ray generating tube 1 is maintained in a vacuum. The insulating tube 10 may have a first open end OP1 and a second open end OP2. The insulating tube 10 may have a tubular shape, such as a cylindrical shape. The insulating tube 10 may be configured to provide vacuum tightness and insulation for the internal space of the insulating tube 10. The insulating tube 10 may be made of a ceramic material, for example, containing alumina or zirconia as a main component. Alternatively, the insulating tube 10 may be made of a glass material, such as borosilicate glass.

[0013] The cathode 30 may be arranged to close the first open end OP1 of the insulating tube 10. The cathode 30 includes an electron emitter 32. The cathode 30 may be arranged not to come into contact with the insulating liquid 60. The X-ray generating device 100 may be configured so that a member having the same potential as the cathode 30 does not come into contact with the insulating liquid 60. The anode 20 may be arranged to close the second open end OP2 of the insulating tube 10. The anode 20 may include a target 23 that generates X-rays when electrons from the electron emitter 32 collide with the target 23. The anode 20 may include a target holding plate 22 that holds the target 23, and an electrode 21 that supports the target holding plate 22. The electrode 21 is made of a conductor, is electrically connected to the target 23, and applies a potential to the target 23. The anode 20 and the container 50 may be maintained at, for example, a ground potential, but may also be maintained at another potential. The target 23 may be made of a material having a high melting point and high X-ray generation efficiency, such as tungsten, tantalum, molybdenum, etc. The target holding plate 22 may be made of a material that easily transmits X-rays, such as beryllium, diamond, etc.

[0014] The container 50 may have a third open end OP3. The container 50 may include, for example, a first portion 52, a second portion 53, a third portion 54, a fourth portion 55, and a fifth portion 56. The first portion 52 may have a tubular shape, such as a cylindrical shape. The first portion 52 may define a third open end OP3 of the container 50. In other words, the first portion 52 may have a third open end OP3. The second portion 53 is made of a conductor and is electrically connected to the anode 20 of the X-ray generating tube 1. The second portion 53 may be understood as constituting an anode together with the electrode 21. The second portion 53 may have a ring shape or a frame shape. The second portion 53 may be arranged so as to be in contact with the insulating liquid 60. Alternatively, the conductive member including the electrode 21 and the second portion 53 may be arranged so as to be in contact with the insulating liquid 60. The electrode 21 and the second portion 53 may be constructed as a single piece of the same material. The fourth portion 55 may have a tubular shape such as a cylindrical shape or a square tube shape. The third portion 54 may be connected to one end of the fourth portion 55 and may have a ring shape or a frame shape. The first portion 52 may be connected to the third portion 54 so as to protrude from the third portion 54. The fifth portion 56 may be connected to the other end of the fourth portion 55. Alternatively, the third portion 54, the fourth portion 55, and the fifth portion 56 may be integrated together to have a hollow spherical shape, except for the joint portion with the first portion 52.

[0015] The insulating liquid 60 can convect in the internal space of the container 50. When the entire outer surface 14 of the insulating tube 10 is in contact with the insulating liquid 60, the insulating tube 10 and the insulating liquid 60 can be charged by friction between the outer surface 14 of the insulating tube 10 and the insulating liquid 60. Such charging is called frictional charging. In general, frictional charging refers to a phenomenon in which charges are transferred between two different materials due to friction between the two materials, and one material is positively charged and the other material is negatively charged. The inventor conducted an experiment in which an insulating tube was left in convecting insulating oil (insulating liquid) and then the potential of the outer surface of the insulating tube was measured with a surface electrometer. As a result, it was confirmed that the outer surface of the insulating tube was charged to the positive polarity and that the amount of charge increased in proportion to time. The polarity of charging due to friction depends on the properties of the rubbing material. Examples of the properties of the material include the triboelectric series and the relative dielectric constant. FIG. 7 shows an example of the triboelectric series for insulating oil. The triboelectric series indicates whether rubbed materials will be charged to a positive or negative polarity, and the order of their tendency to become charged. Materials that are more positively charged in the triboelectric series tend to be charged to a positive polarity, and materials that are more negatively charged tend to be charged to a negative polarity.

[0016] When the outer surface 14 of the insulating tube 10 is positively charged, the insulating performance between the cathode 30 and the anode 20 may be reduced. The insulating performance between the cathode 30 and the anode 20 may depend on the potential difference between the cathode 30 and the anode 20, the resistance between the cathode 30 and the anode 20, the distance between the cathode 30 and the anode 20, and the like. As a result of the experiment, it was found that when the insulating tube 10 is positively charged, the cathode 30 and the anode 20 are short-circuited via the outer surface 14 of the insulating tube 10, as shown diagrammatically by the thick arrow in FIG. 6. In addition, as a result of the experiment, it was also found that when the outer surface 14 of the insulating tube 10, the cathode 30, and the insulating liquid 60 form a triple point, abnormal discharge is likely to occur due to electron avalanche.

[0017] Hereinafter, the X-ray generating device 100 of the present disclosure will be described by way of example through a number of embodiments shown in Figures 2, 3, 4, and 5. Items not mentioned below may follow the basic configuration described with reference to Figure 1.

[0018] FIG. 2 exemplarily and typically illustrates the configuration of the X-ray generator 100 of the first embodiment. The container 50 may be filled with an insulating liquid 60 so as to contact a portion of the anode (e.g., the second portion 53) and cover the outer surface 14 of the insulating tube 10 and the outer surface 34 of the cathode 30. In the X-ray generator 100 of the first embodiment, at least a portion of the insulating tube 10 is surrounded by a member 72 so as to reduce abnormal discharge between the cathode 30 and the anode 20 through the insulating tube 10. The member 72 may be made of an insulating material. More specifically, in the X-ray generator 100 of the first embodiment, the entire outer surface 34 of the insulating tube 10 may be surrounded by the member 72. In another respect, the entire outer surface 14 of the insulating tube 10 may be covered by the member 72. In addition to the entire outer surface 14 of the insulating tube 10, the entire outer surface 34 of the cathode 30 may be covered by the member 72. The first embodiment is effective in preventing the outer surface 14 of the insulating tube 10, the cathode 30, and the insulating liquid 60 from forming a triple point, which can reduce the occurrence of abnormal discharge.

[0019] In order to reduce abnormal discharge between the cathode 30 and the anode 20 through the insulating tube 10, the material of the member 72 may be determined so that the member 72 is negatively charged by frictional charging between the member 72 and the insulating liquid 60, and the insulating liquid 60 is positively charged. When insulating oil is used as the insulating liquid 60, the material of the member 72 may be selected so that the member 72 is negatively charged by frictional charging between the member 72 and the insulating oil, for example, according to the triboelectric series illustrated in FIG. 7. Suitable materials for the member 72 include, for example, polytetrafluoroethylene (Teflon (trademark)), PMMA (polymethylmethacrylate resin), epoxy, and fluororubber (for example, Viton (trademark)). The member 72 may be disposed so as to cover, for example, the entire outer surface 14 of the insulating tube 10 and the outer surface 34 of the cathode 30, and for this purpose, for example, a molding method, a spraying method, a dipping method, or the like may be applied.

[0020] In order to reduce abnormal discharge between the cathode 30 and the anode 20 via the insulating tube 10, the material of the member 72 may be determined so that the relative dielectric constant difference between the member 72 and the insulating liquid 60 is smaller than the relative dielectric constant difference between the member 72 and the insulating tube 10. For example, the member 72 is made of Viton with a relative dielectric constant of 3 or polytetrafluoroethylene with a relative dielectric constant of 2.1, and the insulating tube 10 is made of borosilicate glass with a relative dielectric constant of 4.9 or alumina with a relative dielectric constant of 9. Here, the fact that the relative dielectric constant difference between the member 72 and the insulating liquid 60 is smaller than the relative dielectric constant difference between the member 72 and the insulating tube 10 may be evaluated at the temperature at which X-rays are generated or at room temperature (e.g., 25°C). However, there is no significant difference between the former and the latter.

[0021] Here, a molding method suitable for forming the member 72 so as to cover the X-ray generating tube 1 (the outer surface 14 of the insulating tube 10, and the outer surface 34 of the cathode 30) will be described. The material of the member 72, i.e., the covering material, can be kneaded in advance by a kneading device with a base agent and a curing assistant so as to prevent air bubbles from being introduced, and can be kept at a constant temperature so as to maintain an appropriate flow. In the case of an epoxy resin, the temperature is, for example, around 100°C, but the temperature can be appropriately determined depending on the material used. The covering material can be poured into a container that is one size larger than the X-ray generating tube 1 to be covered. At that time, the covering material can be rapidly cooled due to the temperature difference between the container and the covering material, and the fluidity of the covering material can be reduced. To prevent this, it is desirable to heat the container in advance. After the covering material poured into the container overflows from the container, the amount of covering material can be solidified at an appropriate cooling rate and temperature distribution so as to prevent problems such as shrinkage from occurring.

[0022] In the X-ray generating tube 1, a high voltage is applied between the anode 20 and the cathode 30. If bubbles having a low dielectric constant are present in the member 72 made of the coating material, an electric field will concentrate there, which may induce abnormal discharge. To avoid this, the space in which the process of filling the coating material is performed can be evacuated in advance to a vacuum degree of about several hundred to several thousand Pa using a vacuum pump. In addition, in order to increase the adhesion between the coating material and the X-ray generating tube 1, a primer material may be applied to the surface of the X-ray generating tube 1, or unevenness may be formed by blasting, and then the coating with the member 72 may be performed. It is desirable that the thickness of the member 72 is thin from the viewpoint of heat dissipation of the X-ray generating tube 1. The thickness of the member 72 is, for example, preferably 5 mm or less, more preferably 3 mm or less. The thickness of the member 72 is, for example, preferably 0.3 mm or more, more preferably 0.5 mm or more.

[0023] FIG. 3 exemplarily and typically illustrates the configuration of an X-ray generator 100 according to a second embodiment. Matters not mentioned in the description of the second embodiment may follow the basic configuration described with reference to the first embodiment or FIG. 1. The member 72 may be arranged so as to cover the contact portion C between the cathode 30 and the insulating tube 10. The member 72 may also be arranged so as to cover the cathode 30. The second embodiment is also effective in preventing the outer surface 14 of the insulating tube 10, the cathode 30, and the insulating liquid 60 from forming a triple point, which may reduce the occurrence of abnormal discharge.

[0024] FIG. 4 exemplarily and typically illustrates the configuration of the X-ray generator 100 of the third embodiment. Matters not mentioned in the description of the third embodiment may follow the basic configuration described with reference to the first or second embodiment, or FIG. 1. In the third embodiment, an intermediate layer 75 is provided between the member 72 and the insulating tube 10. The intermediate layer 75 may be made of an insulating material. The intermediate layer 75 may be configured to cover the insulating tube 10. The member 72 may be configured to cover the intermediate layer 75. The intermediate layer 75 may be made of at least one of Kovar glass, nylon, and a mixture containing a metal oxide mainly composed of silica. Providing the intermediate layer 75 is advantageous for forming a smooth surface to cover the outer surface 14 of the insulating tube 10, for example. Forming the intermediate layer 75 is also advantageous for preventing foreign matter from entering between the particles that make up the insulating tube 10. As a result, the creepage withstand voltage on the surface of the member 72 arranged to cover the insulating tube 10 can be improved. This makes it possible to prevent abnormal discharge and extend the life of the X-ray generating device 100.

[0025] FIG. 5 exemplarily and typically illustrates the configuration of the X-ray generator 100 of the fourth embodiment. Matters not mentioned in the description of the fourth embodiment may follow the basic configuration described with reference to the first to third embodiments or FIG. 1. In the fourth embodiment, the member 72 may include a ring-shaped portion. Alternatively, the member 72 may be a ring-shaped portion. The ring-shaped portion may surround a part of the outer surface 14 of the insulating tube 10 in the axial direction (the axial direction of the insulating tube 10, which is also the direction in which the electron beam is emitted from the electron emitter 32) over the entire circumference. The outer surface 14 of the insulating tube 10 may come into contact with the insulating liquid 60 in a region other than the region surrounded by the member 72. It is preferable that the shortest distance between the member 72 and the cathode 30 is smaller than the shortest distance between the member 72 and the anode 20. The insulating tube 10 may be surrounded by a plurality of members 72 (ring-shaped portions). The plurality of members 72 may be arranged spaced apart from each other in the axial direction of the insulating tube 10. The member 72 may be made of, for example, Viton. Even if the outer surface 14 of the insulating tube 10 is charged to the positive polarity side, the member 72 is charged to the negative polarity side, so that the amount of charge to the positive polarity side on the entire outer surface 14 of the insulating tube 10 can be reduced. This can reduce the occurrence of abnormal discharge.

[0026] FIG. 8 exemplarily and typically illustrates the configuration of the X-ray generating device 100 of the fifth embodiment. Matters not mentioned in the description of the fifth embodiment may follow the basic configuration described with reference to the first to fourth embodiments or FIG. 1. The container 50 may define a first space SP1 that houses the driving circuit 40 and a second space SP2 that protrudes from the first space SP1 and houses the X-ray generating tube 1. More specifically, the third portion 54, the fourth portion 55, and the fifth portion 56 of the container 50 may define the first space SP1. Meanwhile, the first portion 52 and the second portion 53 of the container 50 may define the second space SP2. One end of the second space SP2 may form a third opening end OP3. The first portion 52 may form a protruding portion protruding from the third portion 54.

[0027] The insulating tube 10 may be disposed so that its entirety fits within the second space SP2. In other words, the length of the first portion 52 is longer than the length of the insulating tube 10 in the direction D in which the electron beam is emitted from the electron emitter 32. From another perspective, the length of the second space SP2 is longer than the length of the insulating tube 10 in the direction D in which the electron beam is emitted from the electron emitter 32. In this case, the cable 42 is present on the boundary line between the first space SP1 and the second space SP2. In a cross section ( FIG. 8 ) including the direction D in which the electron beam is emitted (the axis of the X-ray generating tube 1), the first portion 52 or the third portion 54 of the container 50 may have a protrusion 90 protruding toward the inside of the container 50.

[0028] The X-ray generating tube 1 may be disposed so that its entirety fits within the second space SP2. The cathode 30 may be disposed so that its entirety fits within the second space SP2. The outer surface 34 of the cathode 30 may have a cylindrical side surface 35 and a circular bottom surface 36. The cylindrical side surface 35 has a non-zero dimension in the axial direction of the insulating tube 10 or in the direction D in which the electron beam is emitted from the electron emitter 32. The bottom surface 36 of the outer surface 34 of the cathode 30 may face the drive circuit 40. The bottom surface 36 has a non-zero dimension in the radial direction of the insulating tube 10 or in a direction perpendicular to the direction D in which the electron beam is emitted from the electron emitter 32.

[0029] In the fifth embodiment, the distance between the cathode 30 and the first portion 52 is shorter than in the first to fourth embodiments. Therefore, abnormal discharge may occur between the cathode 30 and the first portion 52 to which a ground potential may be applied. Therefore, at least a part, preferably the entirety, of the side surface 35 of the outer surface 34 of the cathode 30 that is closest to the first portion 52 may be surrounded by the first member 72. The first member 72 may be disposed so as to surround at least a part, preferably the entirety, of the outer surface 14 of the insulating tube 10 in addition to the side surface 35 of the cathode 30. In addition, the first member 72 is surrounded by a second member 81 spaced apart from the first member 72. The second member 81 may also be disposed spaced apart from the container 50.

[0030] The second member 81 can be disposed so as to block all or part of the straight line path between the first member 72 and the first portion 52 of the storage container 50. The second member 81 can be disposed so as to block all or part of the straight line path between the first member 72 and the protruding portion 90 of the storage container 50. Alternatively, the second member 81 can be disposed so as to block all or part of the straight line path between the cathode 30 and the protruding portion 90 of the storage container 50.

[0031] The second member 81 may be disposed so that an imaginary plane VP11 including one end of the first member 72 and perpendicular to the direction D, and an imaginary plane VP12 including the other end of the first member 72 and perpendicular to the direction D, pass through the second member 81. This makes it possible to prevent abnormal discharge between the first portion 52 of the storage container 50 and the cathode 30. The first member 72 may be disposed so as to contact the cylindrical side surface 35 of the cathode 30, and may have a cylindrical shape. The second member 81 may have a cylindrical shape. The central axis of the first member 72, the central axis of the second member 81, and the central axis of the X-ray generating tube 1 may coincide with each other.

[0032] The first member 72 may be arranged so as to cover at least a portion of the outer surface 14 of the insulating tube 10 in addition to the side surface 35 of the cathode 30. Alternatively, the first member 72 may be arranged so as to cover the entire outer surface 14 of the insulating tube 10 in addition to the side surface 35 of the cathode 30. A configuration in which the first member 72 covers all or a portion of the outer surface 14 of the insulating tube 10 is advantageous for improving the insulation performance between the cathode 30 and the anode 20.

[0033] The thickness (diameter or radial dimension) of the first member 72 is, for example, 15 mm or less when the tube voltage of the X-ray generating tube 1 is 100 keV, and is preferably 50 mm or less when the tube voltage is 300 keV, and more preferably 3 mm or less. The thickness of the first member 72 is, for example, preferably 0.3 mm or more, and more preferably 0.5 mm or more.

[0034] FIG. 9 shows a schematic configuration of a first modified example of the X-ray generating device 100 of the fifth embodiment. As shown in FIG. 9, the second member 81 may have a thick portion 82 that is thicker than other portions on any imaginary line VL2 connecting the convex portion 90 and the outer surface 34 of the cathode 30. In other words, the second member 81 has a thickness greater at a portion overlapping the second imaginary line VL2 than at other portions. In further words, the second member 81 has a first thickness in a first range R1 that overlaps the second imaginary line VL2, and a second thickness in a second range R2 that does not overlap the second imaginary line VL2 and is located closer to the anode 20 than the first range R1, and the maximum value of the first thickness is greater than the maximum value of the second thickness. The thick portion 82 can be configured so that its thickness increases in the direction toward the central axis of the second member 81 (i.e., so that the inner diameter of the second member 81 in the first region R1 is smaller than the inner diameter of the second member 81 in the second region R2).

[0035] Fig. 10 is a schematic diagram showing the configuration of a second modified example of the X-ray generating device 100 of the fifth embodiment. As shown in Fig. 10, the thick portion 82 may be configured so as to increase in thickness in the radial direction of the second member 81 (i.e., so that the outer diameter of the second member 81 in the first region R1 is larger than the outer diameter of the second member 81 in the second region R2).

[0036] Fig. 11 shows a schematic configuration of a third modified example of the X-ray generating device 100 of the fifth embodiment. As shown in Fig. 11, when a thick portion 82 is provided in a second member 81, the first member 72 does not need to be provided. This can reduce costs and improve design freedom.

[0037] 12 is a schematic diagram showing the configuration of a fourth modified example of the X-ray generating device 100 of the fifth embodiment. As shown in FIG. 12, when the second member 81 is provided with the thick portion 82, the first member 72 does not need to be provided. In addition, the thickness of the thick portion 82 in the radial direction of the second member 81 may be larger than the radius of the insulating tube 10.

[0038] The first member 72 and the second member 81 may be made of insulating materials. In particular, the second member 81 is preferably a resin-impregnated glass cloth laminate (e.g., a laminated plate, a laminated pipe) that has been molded under heat and pressure. The resin-impregnated glass cloth laminate may be formed, for example, by laminating or winding a member (prepreg) in which a nonwoven glass fabric is impregnated with a resin such as epoxy resin or phenolic resin, followed by molding under heat and pressure. The second member 81 may be made of, for example, glass epoxy. The second member 81 has a volume resistivity of 1×10 at 25° C. 5 The second member 81 preferably has an insulating property of Ωm or more. The second member 81 may be made of an insulating material such as epoxy resin, polycarbonate, glass, or ceramics.

[0039] In the fifth embodiment illustrated in FIGS. 8, 9, 10, 11, and 12, insulation measures may also be taken between the cathode 30 and the anode 20, as in the first and fourth embodiments.

[0040] FIG. 13 shows a configuration of an X-ray imaging device 200 according to an embodiment. The X-ray imaging device 200 may include an X-ray generating device 100 and an X-ray detecting device 110 that detects X-rays 104 emitted from the X-ray generating device 100 and transmitted through an object 106. The X-ray imaging device 200 may further include a control device 120 and a display device 130. The X-ray detecting device 110 may include an X-ray detector 112 and a signal processing device 114. The control device 120 may control the X-ray generating device 100 and the X-ray detecting device 110. The X-ray detector 112 detects or captures the X-rays 104 emitted from the X-ray generating device 100 and transmitted through the object 106. The signal processing device 114 may process a signal output from the X-ray detector 112 and supply the processed signal to the control device 120. The control device 120 causes the display device 130 to display an image based on the signal supplied from the signal processing device 114.

[0041] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

Claims

1. an X-ray generating tube including: an insulating tube having a first open end and a second open end; a cathode arranged to close the first open end of the insulating tube and including an electron emitting portion; and an anode arranged to close the second open end and including a target that generates X-rays when electrons from the electron emitting portion collide with the target; A drive circuit for driving the X-ray generating tube; a housing that houses the X-ray generating tube and the drive circuit, the container has a third open end, and the X-ray generating tube is disposed so as to close the third open end; The container is filled with an insulating liquid, the container defines a first space for housing the drive circuit and a second space protruding from the first space for housing the X-ray generating tube; the container includes a protrusion surrounding the second space, and one end of the second space constitutes the third opening end; The outer surface of the cathode has a cylindrical side surface, the side surface of the cathode is surrounded by a first member, and the first member is surrounded by a second member disposed between the first member and the container; the container has a protrusion protruding toward the inside of the container in a cross section including an axis of the X-ray generating tube, the second member has a first region overlapping with a virtual line connecting the protrusion and an outer surface of the cathode, and a second region closer to the anode than the first region, and a maximum thickness of the second member in the first region is greater than a maximum thickness of the second member in the second region; 1. An X-ray generating device comprising:

2. the side surface of the cathode is entirely surrounded by the first member; 2. The X-ray generating device according to claim 1 .

3. the side surface of the cathode and at least a part of a side surface of the insulating tube are surrounded by the first member; 2. The X-ray generating device according to claim 1 .

4. the first member surrounds the entire side surface of the cathode and the entire side surface of the insulating tube; 3. The X-ray generating device according to claim 2.

5. The second member is disposed apart from the first member and the container.

2. The X-ray generating device according to claim 1 .

6. The cathode is entirely disposed in the second space.

2. The X-ray generating device according to claim 1 .

7. The insulating tube is entirely disposed in the second space.

2. The X-ray generating device according to claim 1 .

8. At least a portion of the insulating tube is surrounded by the second member.

2. The X-ray generating device according to claim 1 .

9. The first member and the second member are made of an insulating material.

2. The X-ray generating device according to claim 1 .

10. The first member is any one of polytetrafluoroethylene, PMMA (polymethyl methacrylate resin), epoxy, and fluororubber.

2. The X-ray generating device according to claim 1 .

11. The second member is made of a resin-impregnated glass cloth laminate.

2. The X-ray generating device according to claim 1 .

12. The insulating liquid is an insulating oil.

2. The X-ray generating device according to claim 1 .

13. The insulating liquid is a fluorine-based inert liquid.

2. The X-ray generating device according to claim 1 .

14. an X-ray generating tube including: an insulating tube having a first open end and a second open end; a cathode arranged to close the first open end of the insulating tube and including an electron emitting portion; and an anode arranged to close the second open end and including a target that generates X-rays when electrons from the electron emitting portion collide with the target; A drive circuit for driving the X-ray generating tube; a housing that houses the X-ray generating tube and the drive circuit, the container has a third open end, and the X-ray generating tube is disposed so as to close the third open end; The container is filled with an insulating liquid, the container defines a first space for housing the drive circuit and a second space protruding from the first space for housing the X-ray generating tube; the container includes a protrusion surrounding the second space, and one end of the second space constitutes the third opening end; a side surface of the cathode is surrounded by a member disposed between the cathode and the container; the container has a protrusion protruding toward the inside of the container in a cross section including an axis of the X-ray generating tube, the member has a first region overlapping with a virtual line connecting the protrusion and an outer surface of the cathode, and a second region closer to the anode than the first region, and a maximum thickness of the member in the first region is greater than a maximum thickness of the member in the second region; 1. An X-ray generating device comprising:

15. a thickness of the member in the first region is greater than a radius of the insulating tube; 15. The X-ray generating device according to claim 14.

16. The member is made of glass epoxy, polycarbonate, glass, or ceramics.

15. The X-ray generating device according to claim 14.

17. An X-ray generating device according to any one of claims 1 to 16, an X-ray detector for detecting X-rays emitted from the X-ray generating device; An X-ray imaging device comprising: