X-ray generator and X-ray imaging device

Abstract

This X-ray generation device comprises an X-ray generation tube, a drive circuit, and a housing container. The X-ray generation tube includes: an insulation pipe having first and second open ends; a cathode closing the first open end of the insulation pipe and including an electron-emitting portion; and an anode closing the second open end and including a target with which electrons from the electron-emitting portion collide. The housing container has a third open end, which is closed by the X-ray generation tube. The housing container is filled with an insulating liquid. The housing container defines a first space in which the drive circuit is housed, and a second space that protrudes from the first space and in which at least a part of the X-ray generation tube is housed. The housing container includes a protruding portion surrounding the second space, one end of the second space constituting the third open end. A part of the outer surface of the insulation pipe is surrounded by an X-ray blocking member extending from the anode toward the cathode so as to block X-ray. The X-ray blocking member is covered by an insulation member.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes an X-ray generating apparatus including an X-ray generating tube, a tube driving circuit that drives the X-ray generating tube, and a housing that houses the X-ray generating tube and the tube driving circuit. The housing is filled with an insulating liquid, and the insulating liquid ensures insulation performance between the X-ray generating tube and the tube driving circuit.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

[0004] When the X-ray generating apparatus is used for a long period of time, abnormal discharge may occur in the X-ray generating tube. According to an investigation by the inventor, it has been found that abnormal discharge occurs between the cathode and the anode of the X-ray generating tube through the outer surface of the insulating tube. The abnormal discharge may cause the X-ray generating apparatus to stop or malfunction.

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

[0006] A first aspect of the present invention relates to an X-ray generator, the X-ray generator may comprise an X-ray generating tube, a drive circuit for driving the X-ray generating tube, and a housing for housing the X-ray generating tube and the drive circuit. The X-ray generating tube may comprise an insulating tube having a first open end and a second open end, a cathode disposed to close the first open end of the insulating tube and including an electron emission section, and an anode disposed to close the second open end and including a target that generates X-rays when electrons from the electron emission section collide with it. The housing has a third open end, and the X-ray generating tube may be disposed to close the third open end. The housing may be filled with an insulating liquid. The housing may define a first space for housing the drive circuit and a second space protruding from the first space and housing at least a part of the X-ray generating tube. The housing may include a protrusion surrounding the second space, and one end of the second space may constitute the third open end. A portion of the outer surface of the insulating tube may be surrounded by an X-ray shielding member extending from the anode toward the cathode to block X-rays. The X-ray shielding member may be covered by an insulating member.

[0007] A second aspect of the present invention relates to an X-ray imaging apparatus, the X-ray imaging apparatus comprising an X-ray generator relating to the first aspect, and an X-ray detector for detecting X-rays emitted from the X-ray generator. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram schematically illustrates the configuration of a conventional X-ray generator, illustrating the basic configuration of the X-ray generator described herein. [Figure 2] A diagram illustrating and schematically showing the configuration of the X-ray generator of the first embodiment. [Figure 3] A diagram illustrating and schematically showing the configuration of the X-ray generator of the second embodiment. [Figure 4] A diagram illustrating and schematically showing the configuration of the X-ray generator according to the third embodiment. [Figure 5] A diagram illustrating and schematically showing the configuration of the X-ray generator according to the fourth embodiment. [Figure 6] A schematic diagram illustrating the occurrence of abnormal discharge. [Figure 7] A diagram illustrating the triboelectric series in triboelectric charging with an insulating liquid. [Figure 8] A diagram illustrating the problems in the X-ray generator of the fifth embodiment. [Figure 9] A diagram illustrating and schematically showing the configuration of the X-ray generator according to the fifth embodiment. [Figure 10] A schematic diagram showing the configuration of the first modified example of the X-ray generator of the fifth embodiment. [Figure 11] A schematic diagram showing the configuration of a second modified example of the X-ray generator according to the fifth embodiment. [Figure 12] A diagram illustrating and schematically showing the configuration of the X-ray generator according to the sixth embodiment. [Figure 13] A schematic diagram showing a modified configuration of the X-ray generator according to the sixth embodiment. [Figure 14] A diagram illustrating and schematically showing the configuration of the X-ray generator according to the seventh embodiment. [Figure 15] A schematic diagram showing a modified configuration of the X-ray generator according to the eighth embodiment. [Figure 16] A diagram showing the configuration of an X-ray imaging device according to one embodiment. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, the same or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0010] First, the basic configuration of the X-ray generator 100 in this disclosure will be described with reference to Figure 1. The X-ray generator 100 may comprise an X-ray generating tube 1 and a housing container 50 that houses the X-ray generating tube 1. The X-ray generator 100 may further comprise a drive circuit 40 for driving the X-ray generating tube 1, which may be housed in the housing container 50 and connected to the X-ray generating tube 1 via a cable 42. A portion of the X-ray generating tube 1 (the anode 20 described later) may be exposed to the external space of the housing container 50 (the external space of the X-ray generator 100). The internal space of the housing container 50 is filled with an insulating liquid 60. In other words, the internal space of the housing container 50 is filled with the insulating liquid 60, except for the space occupied by the components housed in the housing container 50 (X-ray generating tube 1, cable 42, etc.). The insulating liquid 60 may be, for example, an insulating oil such as mineral oil or 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®).

[0011] 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 under 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 cylindrical shape or other tubular shape. The insulating tube 10 may be configured to provide vacuum airtightness and insulation of the internal space of the insulating tube 10. The insulating tube 10 may be made of a ceramic material mainly composed of alumina or zirconia, for example. Alternatively, the insulating tube 10 may be made of a glass material such as borosilicate glass.

[0012] The cathode 30 may be positioned to close the first open end OP1 of the insulating tube 10. The cathode 30 includes an electron emitter 32. In other words, the cathode 30 may include a closing member 31 positioned to close the first open end OP1 of the insulating tube 10, and an electron emitter 32 supported by the closing member 31. The surface of the closing member 31 may constitute the outer surface 34 of the cathode 30. The cathode 30 may be positioned so that the cathode potential member does not come into contact with the insulating liquid 60. The anode 20 may be positioned 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 it. 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 and is electrically connected to the target 23, providing a potential to the target 23. The anode 20 and the containment vessel 50 may be maintained at, for example, ground potential, but may also be maintained at other potentials. The target 23 may be made of a material with a high melting point and high X-ray generation efficiency, such as tungsten, tantalum, or molybdenum. The target holding plate 22 may be made of a material that readily transmits X-rays, such as beryllium or diamond.

[0013] The storage container 50 may have a third opening end OP3. The storage 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 cylindrical shape such as a cylindrical shape. The first portion 52 may define the third opening end OP3 of the storage container 50. In other words, the first portion 52 may have the third opening 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 to constitute 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 to contact the insulating liquid 60. Alternatively, the conductive member including the electrode 21 and the second portion 53 may be arranged to contact the insulating liquid 60. The electrode 21 and the second portion 53 may be made of the same material and configured as a single piece. The fourth portion 55 may have a cylindrical shape such as a cylindrical shape or a square cylindrical shape. The third portion 54 is 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, except for the joint portion with the first portion 52, the third portion 54, the fourth portion 55, and the fifth portion 56 may be integrated to have a hollow spherical shape.

[0014] The insulating liquid 60 can convect within the internal space of the containment 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 become charged due to friction between the outer surface 14 of the insulating tube 10 and the insulating liquid 60. Such charging is called triboelectric charging. Generally, triboelectric charging is a phenomenon in which electric charge is transferred between two different materials due to friction, causing one material to become positively charged and the other material to become negatively charged. The inventors conducted an experiment in which they left an insulating tube in convecting insulating oil (insulating liquid) and then measured the potential of the outer surface of the insulating tube using a surface potential meter. As a result, they confirmed that the outer surface of the insulating tube became positively charged, and that the amount of charge increased in proportion to time. The polarity of charging due to friction depends on the properties of the materials being rubbed. Examples of material properties include the triboelectric series and relative permittivity. Figure 7 shows an example of the triboelectric series for insulating oil. The triboelectric series shows the order of how easily materials become positively or negatively charged when rubbed. Materials located closer to the positive side of the triboelectric series are more likely to become positively charged, and materials located closer to the negative side are more likely to become negatively charged.

[0015] When the outer surface 14 of the insulating tube 10 becomes positively charged, the insulating performance between the cathode 30 and the anode 20 may decrease. 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, etc. Experimental results showed that when the insulating tube 10 becomes positively charged, the cathode 30 and the anode 20 short-circuit through the outer surface 14 of the insulating tube 10, as schematically shown by the thick arrow in Figure 6. Furthermore, experimental results showed 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 an electron avalanche.

[0016] Hereinafter, the X-ray generator 100 of the present disclosure will be exemplarily described through a plurality of embodiments respectively shown in FIGS. 2, 3, 4, and 5. Matters not mentioned hereinafter may follow the basic configuration described with reference to FIG. 1.

[0017] FIG. 2 exemplarily and schematically shows the configuration of the X-ray generator 100 of the first embodiment. An insulating liquid 60 can be filled in the housing container 50 so as to contact a part of the anode (for example, the second part 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 part 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 can 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 can be surrounded by the member 72. From another perspective, the entire outer surface 14 of the insulating tube 10 can be covered by the member 72. Also, in addition to the entire outer surface 14 of the insulating tube 10, the entire outer surface 34 of the cathode 30 can be covered by the member 72. The first embodiment is effective in avoiding the formation of a triple point by the outer surface 14 of the insulating tube 10, the cathode 30, and the insulating liquid 60, thereby reducing the occurrence of abnormal discharge.

[0018] To reduce abnormal discharge between the cathode 30 and the anode 20 via the insulating tube 10, the material of member 72 should be determined such that member 72 becomes negatively charged and the insulating liquid 60 becomes positively charged due to triboelectric charging between member 72 and the insulating liquid 60. When insulating oil is used as the insulating liquid 60, for example, the material of member 72 can be selected such that member 72 becomes negatively charged due to triboelectric charging between member 72 and the insulating oil, according to the triboelectric series illustrated in Figure 7. Suitable materials for member 72 include, for example, polytetrafluoroethylene (Teflon®), PMMA (polymethyl methacrylate resin), epoxy, and fluororubber (e.g., Viton®). Member 72 may be arranged to cover the entire outer surface 14 of the insulating tube 10 and the outer surface 34 of the cathode 30, for example, by applying a molding method, spray method, or dip method.

[0019] To reduce abnormal discharge between the cathode 30 and the anode 20 via the insulating tube 10, the material of member 72 may be determined such that the difference in relative permittivity between member 72 and the insulating liquid 60 is smaller than the difference in relative permittivity between member 72 and the insulating tube 10. For example, member 72 may be made of Viton with a relative permittivity of 3, or polytetrafluoroethylene with a relative permittivity of 2.1, and the insulating tube 10 may be made of borosilicate glass with a relative permittivity of 4.9, or alumina with a relative permittivity of 9. Here, the fact that the difference in relative permittivity between member 72 and the insulating liquid 60 is smaller than the difference in relative permittivity between member 72 and the insulating tube 10 may be evaluated at the temperature when X-rays are generated, or at room temperature (e.g., 25°C). However, there is no significant difference between the former and the latter.

[0020] Here, a suitable molding method for forming a member 72 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) is described. The material for member 72, i.e., the coating material, can be pre-mixed using a mixing device to prevent air bubbles from forming, and maintained at a constant temperature to maintain appropriate fluidity. In the case of epoxy resins, the temperature is, for example, around 100°C, but the temperature can be appropriately determined depending on the material used. The coating material can be poured into a container that is slightly larger than the X-ray generating tube 1 to be coated. At this time, the coating material may be rapidly cooled due to the temperature difference between the container and the coating material, which may reduce the fluidity of the coating material. To prevent this, it is desirable to pre-heat the container. After the coating material poured into the container overflows from the container, the amount of coating material can be solidified at an appropriate cooling rate and temperature distribution so as not to cause problems such as shrinkage.

[0021] In the X-ray generating tube 1, a high voltage is applied between the anode 20 and the cathode 30. If there are bubbles with a low dielectric constant in the component 72 made of the coating material, the electric field will concentrate there, which can induce abnormal discharge. To avoid this, the space in which the coating material is filled may be pre-emptively evacuated using a vacuum pump to a vacuum level of several hundred to several thousand Pa. In addition, to improve 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 irregularities may be formed by blasting before coating with the component 72. From the viewpoint of heat dissipation of the X-ray generating tube 1, it is desirable for the thickness of the component 72 to be thin. The thickness of the component 72 is preferably, for example, 5 mm or less, and more preferably 3 mm or less. The thickness of the component 72 is preferably, for example, 0.3 mm or more, and more preferably 0.5 mm or more.

[0022] Figure 3 shows an exemplary and schematic configuration of the X-ray generator 100 of the second embodiment. Matters not mentioned in the description of the second embodiment may follow the basic configuration described in the first embodiment or with reference to Figure 1. Member 72 may be positioned to cover the contact portion C between the cathode 30 and the insulating tube 10. Member 72 may also be positioned to cover the cathode 30. The second embodiment is also effective in avoiding the formation of a triple point between the outer surface 14 of the insulating tube 10, the cathode 30, and the insulating liquid 60, thereby reducing the occurrence of abnormal discharge.

[0023] Figure 4 shows an exemplary and schematic 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 in the first or second embodiment or with reference to Figure 1. In the third embodiment, an intermediate layer 75 is provided between member 72 and 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. Member 72 may be configured to cover the intermediate layer 75. The intermediate layer 75 may be made of, for example, Kovar glass, nylon, and at least one mixture containing a metal oxide mainly composed of silica. Providing the intermediate layer 75 is advantageous, for example, to form a smooth surface to cover the outer surface 14 of the insulating tube 10. Also, forming the intermediate layer 75 is advantageous to suppress the intrusion of foreign matter between the particles constituting the insulating tube 10. As a result, the creepage dielectric strength on the surface of member 72, which is arranged to cover the insulating tube 10, can be improved. This prevents abnormal discharge and extends the lifespan of the X-ray generator 100.

[0024] Figure 5 shows an exemplary and schematic configuration of the X-ray generator 100 according to the fourth embodiment. Matters not mentioned in the description of the fourth embodiment may follow the basic configuration described in the first to third embodiments or with reference to Figure 1. In the fourth embodiment, member 72 may include a ring-shaped portion. Alternatively, member 72 may be a ring-shaped portion. The ring-shaped portion may surround a portion of the outer surface 14 of the insulating tube 10 over its entire circumference 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 emission section 32). The outer surface 14 of the insulating tube 10 may be in contact with the insulating liquid 60 in areas other than the area surrounded by member 72. Preferably, the shortest distance between member 72 and the cathode 30 is smaller than the shortest distance between 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 spaced apart from each other with respect to the axial direction of the insulating tube 10. The component 72 may be made of, for example, Viton. Even if the outer surface 14 of the insulating tube 10 is charged to the positive side, the component 72 can be charged to the negative side, thereby reducing the amount of positive charge on the outer surface 14 of the insulating tube 10 as a whole. This can reduce the occurrence of abnormal discharge.

[0025] Figure 9 shows an exemplary and schematic configuration of the X-ray generator 100 of the fifth embodiment. Matters not mentioned in the description of the fifth embodiment may follow the basic configurations described in the first to fourth embodiments or with reference to Figure 1. The housing container 50 may define a first space SP1 for housing the drive circuit 40 and a second space SP2 that protrudes from the first space SP1 and houses at least a part of the X-ray generating tube 1. The other part of the X-ray generating tube 1 may be located in the first space SP1. The third part 54, the fourth part 55 and the fifth part 56 may define the first space SP1. On the other hand, the first part 52 and the second part 53 may define the second space SP2. One end of the second space SP2 may constitute a third open end OP3. The first part 52 may constitute a projection protruding from the third part 54. The second space SP2 protrudes from the first space SP1 and may have a third open end OP3.

[0026] The X-rays generated at target 23 can be emitted in all directions. Therefore, the X-rays generated at target 23 include not only X-rays emitted outside the X-ray generator 100 that irradiate the object being measured, but also back X-rays 105 that are directed towards the inside of the X-ray generator 100 (e.g., the cathode 30, the insulating tube 10).

[0027] To improve the insulation between the X-ray generating tube 1 and the first part 52, it is conceivable to place the first insulating member 73 in the space between the X-ray generating tube 1 and the first part 52, i.e., the second space SP2, as shown in Figure 8. The first insulating member 73 may be placed at a distance from the first part 52 and the X-ray generating tube 1. The first insulating member 73 may be coupled with a third insulating member 77 placed in the first space SP1 so as to surround the drive circuit 40. The third insulating member 77 may be placed at a distance from the housing container 50.

[0028] The first insulating member 73 and the third insulating member 77 may be composed of polytetrafluoroethylene, PMMA (polymethyl methacrylate resin), epoxy resin, polycarbonate, glass, or ceramics. The first insulating member 73 and the third insulating member 77 may be composed of a resin-impregnated glass cloth laminate (e.g., a laminated board, a laminated tube) that has been heat-pressurized. The resin-impregnated glass cloth laminate can be constructed, for example, by laminating or winding a member (prepreg) in which a resin such as epoxy resin or phenolic resin has been impregnated into a glass nonwoven fabric, and then performing heat-pressurized molding. The first insulating member 73 and the third insulating member 77 may be composed of glass epoxy, for example. The first insulating member 73 and the third insulating member 77 have a volume resistivity of 1 × 10 at 25°C. 5 It is preferable that the insulation has an insulating property of Ωm or higher.

[0029] In the X-ray generator 100 having the configuration shown in Figure 8, a problem arose where abnormal discharge occurred between the first insulating member 73 and the X-ray generating tube 1 after continuous generation of X-rays. Upon investigating the cause, it was found that abnormal discharge occurred in the portion of the first insulating member 73 irradiated with rear X-rays 105. Further investigation revealed that the first insulating member 73 became charged due to irradiation with rear X-rays 105, causing abnormal discharge to occur between the first insulating member 73 and the portion of the X-ray generating tube 1 facing it. However, if a space is provided without the first insulating member 73 in the portion irradiated with rear X-rays 105, the insulation performance between the X-ray generating tube 1 and the first portion 52 deteriorates.

[0030] Therefore, in the fifth embodiment, as illustrated in Figure 9, the area in which the first insulating member 73 is placed is limited, and a second insulating member 74 is added. For convenience of explanation, the second space SP2 is defined as a space that includes the third space SP3 and the fourth space SP4. The third space SP3 is a space in which X-rays (back X-rays 105) from the target 23 are incident without being obstructed by either the cathode 30 or the anode 20. The fourth space SP4 is a space in which X-rays (back X-rays 105) from the target 23 are obstructed by either the cathode 30 (including the electron emission section 32) or the anode 20 (i.e., a space in which X-rays from the target 23 are not incident). In the fifth embodiment, the first insulating member 73 is placed in the fourth space SP4 so as to surround the insulating tube 10, and is spaced away from the insulating tube 10 and the housing container 50, while the first insulating member 73 is not placed in the third space SP3. The outer surface 14 of the insulating tube 10 has a first region R1 that is not surrounded by the first insulating member 73, and the first region R1 is surrounded by a second insulating member 74 that is positioned to be in contact with the first region R1. Here, it is preferable that the entire first region R1 is surrounded by the second insulating member 74. The rear X-rays 105 include not only X-rays that arrive directly from the target 23, but also X-rays reflected by members such as the cathode 30 and anode 20.

[0031] The outer surface 14 of the insulating tube 10 has a second region R2 between the first region R1 and the cathode 30, and the first insulating member 73 may be arranged to surround the entire second region R2. The first insulating member 73 may be arranged to extend from the fourth region SP4, which is part of the second region SP2, to the first region SP1. The second insulating member 74 may include a ring-shaped portion. The second insulating member 74 may be made of polytetrafluoroethylene, PMMA (polymethyl methacrylate resin), or epoxy resin.

[0032] As illustrated in Figure 10, the second insulating member 74 is preferably positioned to cover the contact area (boundary) between the cathode 30 and the insulating tube 10. In other words, the second insulating member 74 may be positioned to cover at least a portion of the cathode 30, preferably the entire cathode 30. The second insulating member 74 is preferably positioned to cover the entire outer surface 14 of the insulating tube 10. The second insulating member 74 can be positioned in the first region R1 or covered by a molding method, spray method, or dip method, similar to the member 72 in the first embodiment. Here, in the application of the molding method, the second insulating member 74 may be molded separately from the other members, i.e., by itself, or it may be integrally molded together with the insulating tube 10 using a molding method, such as insert molding.

[0033] A manufacturing method for an X-ray generator 100, as illustrated in Figure 8, may include a step of inserting a first insulating member 73 into the gap between the X-ray generating tube 1 and the first part 52. If the first insulating member 73 comes into contact with or collides with the X-ray generating tube 1 or the first part 52 during such a step, these members may be deformed or particles may be generated due to friction. Such deformation and particle generation can reduce the withstand voltage performance and cause abnormal discharge. In particular, the larger the dimensions of the first insulating member 73 in the direction in which electrons are emitted (the axial direction of the X-ray generating tube 1), the more likely these problems are to occur, which can reduce the yield of the X-ray generator 100. Therefore, as illustrated in Figure 9, reducing the dimensions of the first insulating member 73 in the direction in which electrons are emitted (the axial direction of the X-ray generating tube 1) is effective in improving the yield of the X-ray generator 100.

[0034] As illustrated in Figure 11, the entire insulating tube 10 (or X-ray generating tube 1) may be placed in the second space SP2. In other words, the dimensions of the insulating tube 10 (or X-ray generating tube 1) may be smaller than the dimensions of the first part 52 in the direction in which electrons are emitted (the axial direction of the X-ray generating tube 1). In this case, the cable 42 may be located on the boundary line between the first space SP1 and the second space SP2.

[0035] In the fifth embodiment, as in the first and fourth embodiments, insulation measures between the cathode 30 and the anode 20 may also be implemented.

[0036] Figure 12 shows an exemplary and schematic configuration of the X-ray generator 100 according to the sixth embodiment. Matters not mentioned in the description of the sixth embodiment may follow the basic configuration described in the first to fifth embodiments or with reference to Figure 1. In the fifth embodiment illustrated in Figure 9, abnormal discharge due to rear X-rays 105 is suppressed by limiting the arrangement area of ​​the first insulating member 73. In the sixth embodiment, abnormal discharge due to rear X-rays 105 is suppressed without limiting the arrangement area of ​​the first insulating member 73 (insulating partition). In the sixth embodiment illustrated in Figure 12, an X-ray shielding member 80 is provided. The X-ray shielding member 80 may be arranged such that a portion of the outer surface 14 of the insulating tube 10 is surrounded by the X-ray shielding member 80. The X-ray shielding member 80 may extend from the anode 20 toward the cathode 30 (or its blocking member 31) to block X-rays (rear X-rays 105). The X-ray shielding member 80 may be positioned to extend from the anode 20 to a location between the anode 20 and the cathode 30 (or its blocking member 31). By providing the X-ray shielding member 80, the aforementioned third space SP3, i.e., the space in which X-rays from the target 23 (back X-rays 105) are incident without being blocked by either the cathode 30 or the anode 20, can be eliminated or reduced.

[0037] The X-ray shielding member 80 is preferably at the same potential as the anode 20 (an electrical connection state with the anode 20) from the viewpoint of stabilizing the potential of the X-ray shielding member 80, but it may be at a different potential. The X-ray shielding member 80 is preferably made of a material that easily blocks X-rays, especially a metallic material. The X-ray shielding member 80 may also be made of a bulk metal material or a thin metal film of 100 μm or less. Since dielectric breakdown may occur if there is a gap between the X-ray shielding member 80 and the insulating tube 10, the X-ray shielding member 80 may be positioned to be in contact with the outer surface 14 of the insulating tube 10. The X-ray shielding member 80 may be formed, for example, by a plating method or a PVD method so as to be in contact with the outer surface 14 of the insulating tube 10.

[0038] A potential different from the potential of the cathode 30, for example, the potential of the anode 20, may be applied to the X-ray shielding member 80. In this case, the creepage distance between the cathode 30 and the X-ray shielding member 80 becomes shorter than the creepage distance between the cathode 30 and the anode 20 when the X-ray shielding member 80 is not provided. This can cause abnormal discharge. Therefore, it is preferable that the X-ray shielding member 80 be covered with an insulating member 74. The insulating member 74 may be arranged to cover the contact portion (boundary) between the X-ray shielding member 80 and the insulating tube 10. The insulating member 74 may also be arranged to cover the exposed portion (the portion not covered by the X-ray shielding member 80) of the outer surface 14 of the insulating tube 10. Preferably, the insulating member 74 may be arranged to cover the entire X-ray shielding member 80 and the entire exposed portion of the outer surface 14 of the insulating tube 10. Furthermore, the insulating member 74 may be positioned to cover the contact portion (boundary) between the cathode 30 (or its closing member 31) and the insulating tube 10. The insulating member 74 may be positioned to contact the outer surface of the X-ray shielding member 80. The outer surface 34 of the cathode 30 (or its closing member 31) has cylindrical side surfaces and a circular bottom surface, and at least the entirety of the side surfaces of the outer surface 34 of the cathode 30 may be covered by the insulating member 74. Moreover, it is preferable that the entire outer surface 34 of the cathode 30 is covered by the insulating member 74.

[0039] In the second space SP2, a first insulating member 73 (insulating partition) may be arranged at a distance from the insulating tube 10 and the housing container 50 so as to surround the insulating tube 10 and the insulating member 74, but the first insulating member 73 is not required. If the first insulating member 73 is not arranged, the X-ray shielding member 80 can suppress abnormal discharge caused by the charging of the first part 52 of the housing container 50 (for example, if the first part 52 is made of an insulator, or if the first part 52 is made of a conductor but is in a floating state), the insulating liquid 60, and the second insulating member 74 by the rear X-rays 105.

[0040] As illustrated in Figure 13, the X-ray shielding member 80 does not need to block all of the rear X-rays 105. Extending the X-ray shielding member 80 toward the cathode 30 can shorten the creepage distance. Therefore, the extension range of the X-ray shielding member 80, or the range over which the X-ray shielding member 80 covers the insulating tube 10, should be determined by considering both the disadvantage of a shorter creepage distance and the advantage of blocking the rear X-rays 105. From another perspective, the extension range of the X-ray shielding member 80 can be determined according to the intensity distribution of the rear X-rays 105.

[0041] Figure 14 illustrates and schematically shows the configuration of the X-ray generator 100 according to the seventh embodiment. Matters not mentioned in the description of the seventh embodiment may follow the basic configurations described in the first to sixth embodiments or with reference to Figure 1. In one aspect of the seventh embodiment, the outer surface 14 of the insulating tube 10 is surrounded by an insulating member 74, and an adhesion layer 81 is provided between the outer surface 14 of the insulating tube 10 and the insulating member 74. By providing the adhesion layer 81, the adhesion between the outer surface 14 of the insulating tube 10 and the insulating member 74 is improved. This reduces air bubbles and / or gaps between the outer surface 14 of the insulating tube 10 and the insulating member 74, which can reduce the decrease in dielectric strength and further reduce the occurrence of abnormal discharge. The insulating member 74 may be arranged to cover the boundary between the cathode 30 (or its closing member 31) and the insulating tube 10. The adhesion layer 81 and the insulating member 74 may be arranged to cover the entire outer surface 34 of the insulating tube 10. The adhesion layer 81 may be composed of, for example, a silane coupling agent. The adhesion layer 81 may be composed of a titanium coupling agent.

[0042] In other respects, the X-ray generator 100 of the seventh embodiment may include the X-ray shielding member 80 described in the sixth embodiment. If the X-ray shielding member 80 is included, the adhesion layer 81 may also be placed between the insulating member 74 and the X-ray shielding member 80.

[0043] Figure 15 illustrates and schematically shows the configuration of the X-ray generator 100 according to the eighth embodiment. Matters not mentioned in the description of the eighth embodiment may follow the basic configurations described in the first to seventh embodiments or with reference to Figure 1. In one aspect of the eighth embodiment, the outer surface 14 of the insulating tube 10 is surrounded by an insulating member 74, and an adhesion layer 81 is provided between the outer surface 14 of the insulating tube 10 and the insulating member 74. By providing the adhesion layer 81, the adhesion between the outer surface 14 of the insulating tube 10 and the insulating member 74 is improved. This reduces air bubbles and / or gaps between the outer surface 14 of the insulating tube 10 and the insulating member 74, which can reduce the decrease in dielectric strength and further reduce the occurrence of abnormal discharge. The insulating member 74 may be arranged to cover the boundary between the cathode 30 (or its closing member 31) and the insulating tube 10. The adhesion layer 81 and the insulating member 74 may be arranged to cover the entire outer surface 34 of the insulating tube 10. The adhesion layer 81 may be composed of, for example, a silane coupling agent. The adhesion layer 81 may be composed of a titanium coupling agent.

[0044] In the eighth embodiment, the X-ray generator 100 does not include the first insulating member 73, the third insulating member 77, or the X-ray shielding member 80. However, by providing an adhesion layer 81 between the outer surface 14 of the insulating tube 10 and the insulating member 74, the occurrence of abnormal discharge can be reduced.

[0045] Figure 16 shows the configuration of an X-ray imaging apparatus 200 according to one embodiment. The X-ray imaging apparatus 200 may include an X-ray generator 100 and an X-ray detection device 110 that detects X-rays 104 emitted from the X-ray generator 100 and transmitted through an object 106. The X-ray imaging apparatus 200 may further include a control device 120 and a display device 130. The X-ray detection device 110 may include an X-ray detector 112 and a signal processing unit 114. The control device 120 can control the X-ray generator 100 and the X-ray detection device 110. The X-ray detector 112 detects or images the X-rays 104 emitted from the X-ray generator 100 and transmitted through the object 106. The signal processing unit 114 can process the signal output from the X-ray detector 112 and supply the processed signal to the control device 120. Based on the signal supplied by the signal processing unit 114, the control device 120 causes the display device 130 to display an image.

[0046] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention.

Claims

1. An X-ray generating tube comprising: an insulating tube having a first open end and a second open end; a cathode disposed to close the first open end of the insulating tube and including an electron emission section; and an anode disposed to close the second open end and including a target that generates X-rays when electrons from the electron emission section collide with it; A drive circuit for driving the X-ray generating tube, It comprises an X-ray generating tube and a housing container for housing the drive circuit, The containment container has a third open end, and the X-ray generating tube is positioned to close the third open end. The aforementioned container is filled with an insulating liquid. The aforementioned housing container defines a first space for housing the drive circuit and a second space that protrudes from the first space and houses at least a portion of the X-ray generating tube. The containment container includes a protrusion surrounding the second space, and one end of the second space constitutes the third open end. A portion of the outer surface of the insulating tube is surrounded by an X-ray shielding member that extends from the anode toward the cathode to block X-rays. The aforementioned X-ray shielding member is covered by an insulating member. An X-ray generator characterized by the following features.

2. The X-ray shielding member extends from the anode to a position between the anode and the cathode. The X-ray generator according to feature 1.

3. The X-ray shielding member is in contact with the outer surface of the insulating tube. The X-ray generator according to feature 1.

4. The insulating member is in contact with the X-ray shielding member. The X-ray generator according to feature 3.

5. The insulating member covers the entire outer surface of the X-ray shielding member. The X-ray generator according to feature 1.

6. In the second space, an insulating partition wall is arranged so as to surround the insulating tube and the insulating member, and is separated from the insulating tube and the housing container. The X-ray generator according to feature 1.

7. The outer surface of the cathode has cylindrical side surfaces and a circular bottom surface. At least the entirety of the side surface of the outer surface of the cathode is covered by the insulating member. The X-ray generator according to feature 1.

8. The entire outer surface of the cathode is covered by the insulating member. The X-ray generator according to feature 7.

9. The entire insulating tube is placed in the second space. The X-ray generator according to feature 1.

10. An adhesive layer is provided between the outer surface of the insulating tube and the insulating member. The X-ray generator according to feature 1.

11. The aforementioned adhesion layer contains a silane coupling agent. The X-ray generator according to claim 10.

12. An X-ray generating tube comprising: an insulating tube having a first open end and a second open end; a cathode disposed to close the first open end of the insulating tube and including an electron emission section; and an anode disposed to close the second open end and including a target that generates X-rays when electrons from the electron emission section collide with it; A drive circuit for driving the X-ray generating tube, It comprises an X-ray generating tube and a housing container for housing the drive circuit, The containment container has a third open end, and the X-ray generating tube is positioned to close the third open end. The aforementioned container is filled with an insulating liquid. The aforementioned housing container defines a first space for housing the drive circuit and a second space that protrudes from the first space and houses at least a portion of the X-ray generating tube. The containment container includes a protrusion surrounding the second space, and one end of the second space constitutes the third open end. The outer surface of the insulating tube is surrounded by an insulating member, and an adhesive layer is provided between the outer surface of the insulating tube and the insulating member. An X-ray generator characterized by the following features.

13. The insulating member is positioned to cover the boundary between the cathode and the insulating tube. The X-ray generator according to claim 12.

14. The adhesion layer and the insulating member are arranged to cover the entire outer surface of the insulating tube. The X-ray generator according to claim 12.

15. The insulating member is composed of one of the following: polytetrafluoroethylene, PMMA (polymethyl methacrylate resin), or epoxy resin. The X-ray generator according to claim 12.

16. The insulating liquid is an insulating oil. The X-ray generator according to any one of claims 1 to 15.

17. An X-ray generator according to any one of claims 1 to 15, An X-ray detector for detecting X-rays emitted from the aforementioned X-ray generator, An X-ray imaging apparatus characterized by comprising the following features.

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