Cathode assembly of x-ray tube, and x-ray tube

Abstract

A cathode assembly (100) of an X-ray tube, and an X-ray tube. The cathode assembly (100) of an X-ray tube comprises: a focusing cover (1), which has a cavity (11); a filament slot (6), which is arranged in the cavity (11) and is provided with a hollowed-out opening (61); a first side plate (2), which has a flat first outer surface (221) and is at least partially located in the hollowed-out opening (61); a second side plate (3), which has a flat second outer surface (321) and is at least partially located in the hollowed-out opening (61), wherein the second outer surface (321) faces the first outer surface (221), a first slit (4) being formed therebetween, and the first side plate (2) and the second side plate (3) can move opposite each other or move away from each other; and a first electron emitter (5), which is arranged in the first slit (4). A first gap (71), which is not zero, is provided between a first inner surface (222) of the first side plate (2) that is opposite the first outer surface (221) and a first edge (611) of the hollowed-out opening (61) in the width direction of the first slit (4); and / or a second gap (72), which is not zero, is provided between a second inner surface (322) of the second side plate (3) that is opposite the second outer surface (321) and a second edge (612) facing the hollowed-out opening (61). The solution can reduce the forming difficulty and cost of a slit, and prolong the service life of an X-ray tube.

Description

Cathode assembly of X-ray tube and X-ray tube Technical Field

[0001] The embodiments of the present invention relate to the field of X-ray tubes, and in particular to a cathode assembly of an X-ray tube and an X-ray tube. Background Art

[0002] An X-ray tube is a high-voltage, high-vacuum electronic device with an electron emission source. Electrons are emitted from the electron emitter located in the filament slot, focused by the focusing mask of the cathode, and accelerated by the high-voltage electric field of tens or hundreds of kilovolts between the cathode and the anode to form an electron beam. The electron beam bombards the anode target, forming an electron spot and generating X-rays.

[0003] The cathode typically consists of an electron emitter, a filament trough, and a focusing mask. The filament trough is designed with a slot, with the electron emitter located in the center of the slot, generating electrons. The focusing mask typically has a focusing shape, which converges and focuses the emitted electrons under the influence of the high-voltage electric fields from the cathode and anode. The slot in the filament trough acts as a slit, and the slot width (and therefore the slit width) has a decisive influence on the size of the electron spot on the anode target surface.

[0004] Existing technology adjusts the size of the electron spot by machining the filament trough to create grooves of varying widths, resulting in slits of varying widths. This allows for a range of X-ray tubes with varying spot sizes. This means that X-ray tubes with varying spot sizes require filament troughs of varying specifications. Micron-scale electron spots typically require slits with narrower groove widths, which complicates filament trough machining and, consequently, slit formation. This, in turn, complicates cathode assembly machining. Furthermore, the resulting groove surface is uneven, impacting the electron emitter drive power and tube life.

[0005] Summary of the Invention

[0006] The technical problem solved by the embodiments of the present invention at least is that it is difficult to form the slit, which in turn leads to greater difficulty in processing the cathode assembly.

[0007] To solve the above technical problems, an embodiment of the present invention provides a cathode assembly of an X-ray tube, comprising: a focusing mask, the focusing mask having a cavity; a filament slot body, disposed in the cavity and connected to the focusing mask, the filament slot body having a hollow opening; a first side plate, disposed in the cavity, the first side plate fixedly connected to the filament slot body, the first side plate having a flat first outer surface, at least a portion of the first outer surface being located in the hollow opening; a second side plate, disposed in the cavity, the second side plate fixedly connected to the filament slot body, the second side plate having a flat second outer surface, at least a portion of the second outer surface being located in the hollow opening, the second outer surface facing the first outer surface and forming a first slit, the The first side plate and the second side plate can move toward each other or away from each other; the first electron emitter is arranged in the first slit, and along the width direction of the first slit, the first side plate has a first inner surface arranged opposite to the first outer surface, the first inner surface faces the first edge of the hollow opening, and a non-zero first gap exists between the first inner surface and the first edge; and / or, along the width direction of the first slit, the second side plate has a second inner surface arranged opposite to the second outer surface, the second inner surface faces the second edge of the hollow opening, and a non-zero second gap exists between the second inner surface and the second edge; wherein, the first edge and the second edge are arranged opposite to each other along the width direction of the first slit.

[0008] Optionally, the first side panel includes a first connecting portion and a first cantilever connected to each other, the first connecting portion is fixedly connected to the filament trough body and is located outside the hollow opening, the first cantilever is bent relative to the first connecting portion and extends into the hollow opening, wherein the first outer surface is located on the first cantilever; the second side panel includes a second connecting portion and a second cantilever connected to each other, the second connecting portion is fixedly connected to the filament trough body and is located outside the hollow opening, the second cantilever is bent relative to the second connecting portion and extends into the hollow opening, wherein the second outer surface is located on the second cantilever.

[0009] Optionally, the roughness of the first outer surface is less than or equal to 0.2 μm, and / or the roughness of the second outer surface is less than or equal to 0.2 μm.

[0010] Optionally, a first heat insulating member is provided between the first connecting portion and the filament slot body; and / or a second heat insulating member is provided between the second connecting portion and the filament slot body.

[0011] Optionally, the second side plate also has a flat second inner surface arranged opposite to the second outer surface, and the cathode assembly also includes: a third side plate, arranged in the cavity, the third side plate having a flat third outer surface, the third outer surface facing the second inner surface and forming a second slit; a second electron emitter, located in the second slit.

[0012] Optionally, the first side panel includes a first connecting portion and a first cantilever connected to each other, the first connecting portion is fixedly connected to the filament trough body and is located outside the hollow opening, the first cantilever is bent relative to the first connecting portion and extends into the hollow opening, wherein the first outer surface is located on the first cantilever; the second side panel is plate-shaped, and is connected to the filament trough body at both ends along the length direction of the first slit; the third side panel includes a third connecting portion and a third cantilever connected to each other, the third connecting portion is fixedly connected to the filament trough body and is located outside the hollow opening, the third cantilever is bent relative to the third connecting portion and extends into the hollow opening, wherein the third outer surface is located on the third cantilever; wherein, the second side panel is located between the first side panel and the third side panel.

[0013] Optionally, the filament trough body is provided with a first guide portion, the first side panel is provided with a first matching portion, the first guide portion is adapted to the first matching portion, and guides the first side panel to move relative to the filament trough body along the width direction of the first slit; and / or, the filament trough body is provided with a second guide portion, the second side panel is provided with a second matching portion, the second guide portion is adapted to the second matching portion, and guides the second side panel to move relative to the filament trough body along the width direction of the first slit.

[0014] Optionally, the cathode assembly also includes: a first supporting electrode column and a second supporting electrode column, which are located in the cavity, and the first supporting electrode column and the second supporting electrode column are electrically connected to the first electron emitter respectively, and support the first electron emitter in the first slit; a tube shell, which partially extends into the cavity and is connected to the filament slot body; a flange, which is located in the cavity and is fixedly connected to the first supporting electrode column, the second supporting electrode column, the filament slot body and the tube shell.

[0015] Optionally, the width of the first slit ranges from 0.4 mm to 4 mm.

[0016] The present invention further provides an X-ray tube, comprising: a housing; any one of the above-mentioned cathode components, disposed in the housing; and an anode, disposed in the housing.

[0017] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0018] The present invention provides a cathode assembly for an X-ray tube, comprising a first side plate and a second side plate disposed within a cavity of a focusing mask. The first side plate has a flat first outer surface, and the second side plate has a flat second outer surface. The second outer surface faces the first outer surface and forms a first slit for accommodating a first electron emitter. Because the first and second side plates are separate components and can be processed separately, independent groove processing is not required when forming the first slit, thereby avoiding a series of problems associated with groove processing. Compared to forming a slit by cutting a groove in a filament trough, the difficulty of forming the first slit in the present invention is greatly reduced, thereby reducing the difficulty of processing the cathode assembly. In addition, the first and second side plates can be moved toward or away from each other. By adjusting the positions of the first and second side plates within the cavity, the width of the first slit can be adjusted, which helps meet the requirements of different electron beam spots and improves the versatility and flexibility of the cathode assembly. The first gap can reduce the heat transfer from the heated first side plate to the filament slot body, and the second gap can reduce the heat transfer from the heated second side plate to the filament slot body, thereby reducing the amount of gas released by the filament slot body due to excessive temperature, avoiding the influence of the gas on the vacuum degree of the X-ray tube, and extending the service life of the X-ray tube.

[0019] Furthermore, by adjusting the positions of the first and second side plates within the cavity, for example by moving them toward each other so that the first and second outer surfaces are closer together, a relatively narrow first slit can be obtained. Conversely, by moving the first and second side plates away from each other so that the first and second outer surfaces are farther apart, a relatively wide first slit can be obtained. In other words, using the same components, X-ray tubes with different electron spot sizes can be produced. This improves the versatility of the components in the cathode assembly, facilitates the simultaneous mass production of X-ray tubes with different electron spot sizes, improves production efficiency, and helps reduce costs.

[0020] In addition, since the first side plate and the second side plate are separate components and can be processed separately, it is helpful to use polishing and other methods to reduce surface roughness, facilitate the cleaning treatment required for high vacuum parts, thereby avoiding problems such as surface roughness, difficulty in cleaning and sparking caused by the difficulty of groove processing of the filament groove body, and improving the life of the X-ray tube.

[0021] Furthermore, the roughness of the first outer surface is less than or equal to 0.2 μm, and / or the roughness of the second outer surface is less than or equal to 0.2 μm. This makes the first outer surface and / or the second outer surface relatively smooth and bright, reducing the thermal radiation absorption capacity of the first and second outer surfaces while enhancing their reflective capacity. In other words, by increasing the amount of heat reflected from the first electron emitter, the absorption of heat from the first electron emitter is reduced, thereby reducing the power required by the first electron emitter to maintain emission, which helps reduce the load power required by the hot cathode.

[0022] Furthermore, the first thermal insulation member provided between the first connection portion and the filament trough body can reduce or even isolate the heat of the first electron emitter from being transferred from the first connection portion to the filament trough body. The second thermal insulation member provided between the second connection portion and the filament trough body can reduce or even isolate the heat of the first electron emitter from being transferred from the second connection portion to the filament trough body. In this way, the absorption of heat from the first electron emitter by the filament trough body and the focusing mask can be further reduced, thereby further reducing the power required by the first electron emitter to maintain emission, which is conducive to reducing the load power required by the hot cathode. In addition, by reducing the absorption of heat from the first electron emitter by the filament trough body, the amount of gas released by the filament trough body due to excessive temperature can also be reduced, thereby avoiding the impact of the gas on the vacuum degree of the X-ray tube and extending the service life of the X-ray tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a schematic structural diagram of a cathode assembly of an X-ray tube according to an embodiment of the present invention at one viewing angle;

[0024] FIG2 is a schematic structural diagram of a cathode assembly of an X-ray tube according to an embodiment of the present invention from another perspective;

[0025] FIG3 is a schematic structural diagram of a cathode assembly of an X-ray tube according to an embodiment of the present invention from another perspective;

[0026] FIG4 is a schematic diagram of the local structure of point A in FIG3 ;

[0027] FIG5 is a cross-sectional view taken along the CC direction of FIG1;

[0028] FIG6 is a schematic diagram of the local structure of point D in FIG5;

[0029] 7 is a schematic structural diagram of a cathode assembly of another X-ray tube in an embodiment of the present invention;

[0030] FIG8 is a schematic diagram of the local structure of point B in FIG7;

[0031] Explanation of Reference Numerals: 100 - cathode assembly; 1 - focusing mask; 11 - cavity; 2 - first side plate; 21 - first connecting portion; 22 - first cantilever; 221 - first outer surface; 222 - first inner surface; 3 - second side plate; 31 - second connecting portion; 32 - second cantilever; 321 - second outer surface; 322 - second inner surface; 4 - first slit; 5 - first electron emitter; 6 - filament slot; 61 - hollow opening; 611 - first edge; 612 - second edge; 71 -first gap; 72-second gap; 73-third gap; 8-third side plate; 81-third connecting portion; 82-third cantilever; 821-third outer surface; 822-third inner surface; 91-second electron emitter; 92-second slit; 93-first supporting electrode column; 94-second supporting electrode column; 95-tube shell; 96-flange; 97-first fastener; 98-second fastener; x-width direction of the first slit; y-length direction of the first slit. DETAILED DESCRIPTION

[0032] In the prior art, the filament slot is usually slotted to obtain slots of different slot widths, and the electron emitter is located in the slot. In some scenarios where smaller electron spot requirements are required, such as micron-level electron spots, a narrower slot width is usually required. The narrower the slot width, the more difficult it is to process. In addition, when processing narrower slots, it is easy to cause a series of problems such as poor slot surface quality, roughness, easy adhesion of dirt residue caused by machining on the surface, difficulty in cleaning, and the risk of sparks. These problems are not conducive to the life of X-ray tubes with high cleanliness and high reliability requirements.

[0033] In addition, the rough groove surface has a strong heat absorption capacity. For hot cathodes, higher thermal power is required to maintain the emission temperature. A single electron emitter usually has a load power of 10 watts to tens of watts. Not only is the load power large, but it also causes the cathode temperature to reach hundreds of degrees, which brings challenges to the degassing treatment of parts in the cathode area and affects the reliability of the X-ray tube during operation. This is especially true in scenarios where there are dozens or hundreds of electron emitters at the same time, where the impact is more obvious.

[0034] To at least address the aforementioned difficulty in slit fabrication, an embodiment of the present invention provides a cathode assembly for an X-ray tube, comprising a first side plate and a second side plate disposed within a focusing mask cavity. The first side plate has a flat first outer surface, and the second side plate has a flat second outer surface. The second outer surface faces the first outer surface and forms a first slit for accommodating a first electron emitter. Because the first and second side plates are separate components and can be fabricated independently, separate groove fabrication is not required to form the first slit, thereby avoiding a series of problems associated with groove fabrication. Compared to forming a slit by cutting a groove in a filament trough, the present invention significantly reduces the difficulty of forming the first slit, thereby reducing the difficulty of fabricating the cathode assembly. Furthermore, the first and second side plates are movable toward or away from each other. By adjusting the positions of the first and second side plates within the cavity, the width of the first slit can be adjusted, helping to meet different electron spot requirements and enhancing the versatility and flexibility of the cathode assembly.

[0035] A non-zero first gap is defined between the first inner surface of the first side plate and the first edge of the first side plate, and a non-zero first gap is defined between the second inner surface of the second side plate and the second edge of the second side plate. When the cathode assembly is operating, the first and second side plates are heated by the heat of the first electron emitter. Thus, the first gap reduces the amount of heat transferred from the heated first side plate to the filament trough, and the second gap reduces the amount of heat transferred from the heated second side plate to the filament trough. This reduces the amount of gas released from the filament trough due to excessive temperature, prevents the gas from affecting the vacuum level of the X-ray tube, and extends the service life of the X-ray tube.

[0036] In order to make the above-mentioned objects, features and beneficial effects of the embodiments of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] Figure 1 is a schematic diagram of the structure of a cathode assembly of an X-ray tube according to an embodiment of the present invention, viewed from one perspective; Figure 2 is a schematic diagram of the structure of a cathode assembly of an X-ray tube according to an embodiment of the present invention, viewed from another perspective; Figure 3 is a schematic diagram of the structure of a cathode assembly of an X-ray tube according to an embodiment of the present invention, viewed from yet another perspective; Figure 4 is a schematic diagram of the partial structure of point A in Figure 3; Figure 5 is a cross-sectional view along the CC direction of Figure 1; and Figure 6 is a schematic diagram of the partial structure of point D in Figure 5. The specific structure of the cathode assembly of the X-ray tube (hereinafter referred to as the cathode assembly) will be described below in conjunction with Figures 1 to 6. The CC direction is also the width direction x of the first slit 4.

[0038] In a specific implementation, the cathode assembly 100 of the X-ray tube includes: a focusing cover 1 , a filament slot 6 , a first side plate 2 , a second side plate 3 and a first electron emitter 5 .

[0039] The focusing mask 1 has a cavity 11. The focusing mask 1 may also be called a focusing body, a cathode head, a collecting mask, etc. The focusing mask 1 can focus the electrons emitted by the first electron emitter 5.

[0040] The filament trough 6 is disposed in the cavity 11 and connected to the focusing mask 1. The filament trough 6 and the focusing mask 1 can be connected by various suitable means such as snap connection, welding, and threaded connection, which are not limited here. The filament trough 6 has a hollow opening 61.

[0041] The first side plate 2 is disposed in the cavity 11 and has a flat first outer surface 221 . The first side plate 2 is fixedly connected to the filament trough 6 , and at least a portion of the first outer surface 221 is located in the hollow opening 61 .

[0042] The second side plate 3 is disposed in the cavity 11 and has a flat second outer surface 321 . The second side plate 3 is fixedly connected to the filament trough 6 , and at least a portion of the second outer surface 321 is located in the hollow opening 61 .

[0043] The second outer surface 321 faces the first outer surface 221 and forms a first slit 4. That is, the second outer surface 321 and the first outer surface 221 are arranged face to face with a gap therebetween, which is the first slit 4.

[0044] The first side panel 2 and the second side panel 3 can move toward or away from each other. When the first side panel 2 and the second side panel 3 move toward each other, they move closer together, reducing the width of the first slit 4. When the first slit 4 moves away from each other, the first side panel 2 and the second side panel 3 move away from each other (moving away from each other, also known as moving away from each other), which can increase the width of the first slit 4. In this way, the width of the first slit 4 can be increased or decreased according to actual needs.

[0045] The first electron emitter 5 , which may also be called a filament, is disposed in the first slit 4 .

[0046] In some non-limiting embodiments, the first electron emitter 5 is disposed at the center of the first slit 4 .

[0047] The size of the hollow opening 61 is larger than that of the first slit 4. For example, at least along the width direction x of the first slit 4, the size of the hollow opening 61 is larger than that of the first slit 4. In this case, the hollow opening 61 is used to avoid the first side plate 2, the second side plate 3, and other components, or to avoid some wiring, etc. The hollow opening 61 does not affect the size of the electron spot, and the hollow opening 61 does not increase the processing difficulty. In this way, the first side plate 2 and the second side plate 3 are fixedly connected to the filament trough body 6. Based on minor modifications to the existing cathode assembly 100, a narrower first slit 4 can be obtained with less processing difficulty, effectively reducing processing costs and difficulty.

[0048] In a specific implementation, along the width direction x of the first slit 4, the first side panel 2 has a first inner surface 222 arranged opposite to the first outer surface 221, the first inner surface 222 faces the first edge 611 of the hollow opening 61, and there is a non-zero first gap 71 between the first inner surface 222 and the first edge 611.

[0049] In a specific embodiment, along the width direction x of the first slit 4, the second side panel 3 has a second inner surface 322 disposed opposite the second outer surface 321. The second inner surface 322 faces the second edge 612 of the hollow opening 61, and a non-zero second gap 72 is defined between the second inner surface 322 and the second edge 612. The first edge 611 and the second edge 612 are disposed opposite each other along the width direction x of the first slit 4.

[0050] When the cathode assembly 100 is working, the first side plate 2 and the second side plate 3 will be heated by the heat of the first electron emitter 5. In this way, the first gap 71 can reduce the heat from the heated first side plate 2 to the filament slot 6. The second gap 72 can reduce the heat from the heated second side plate 3 to the filament slot 6. This reduces the amount of gas released by the filament slot 6 due to excessive temperature, avoids the influence of the gas on the vacuum degree of the X-ray tube, and extends the service life of the X-ray tube.

[0051] As can be seen from the above, a first slit 4 is formed by the flat first outer surface 221 of the first side plate 2 and the flat second outer surface 321 of the second side plate 3. The first slit 4 is used to place the first electron emitter 5. Since the first side plate 2 and the second side plate 3 are separate components and can be processed separately, there is no need to independently perform groove processing when forming the first slit 4, thereby avoiding a series of problems caused by groove processing. Compared with the slit obtained by cutting a groove on the filament slot body, the difficulty of forming the first slit 4 in the present invention is greatly reduced, thereby reducing the difficulty of processing the cathode assembly. In addition, the first side plate 2 and the second side plate 3 can be moved toward or away from each other. By adjusting the position of the first side plate 2 and the second side plate 3 in the cavity 11, that is, by moving the first side plate 2 and the second side plate 3 toward or away from each other, the width of the first slit 4 can be adjusted, which helps to meet the requirements of different electron spots and improve the versatility and flexibility of the cathode assembly 100. The first gap can reduce the heat transfer from the heated first side plate 2 to the filament slot 6, and the second gap can reduce the heat transfer from the heated second side plate 3 to the filament slot 6, thereby reducing the amount of gas released by the filament slot 6 due to excessive temperature, avoiding the influence of the gas on the vacuum degree of the X-ray tube, and extending the service life of the X-ray tube.

[0052] In a specific embodiment, the first side panel 2 includes a first connecting portion 21 and a first cantilever 22 that are connected to each other. The first connecting portion 21 is fixedly connected to the filament trough 6. The first cantilever 22 is bent relative to the first connecting portion 21 and extends into the hollow opening 61. The first outer surface 221 is located on the first cantilever 22. The first inner surface 222 is also located on the first cantilever 22.

[0053] The second side panel 3 includes a second connecting portion 31 and a second cantilever 32 that are connected to each other. The second connecting portion 31 is fixedly connected to the filament trough 6. The second cantilever 32 is bent relative to the second connecting portion 31 and extends into the hollow opening 61. The second outer surface 321 is located on the second cantilever 32. The second inner surface 322 is also located on the second cantilever 32. In this way, the first cantilever 22 and the second cantilever 32 are arranged face to face.

[0054] In some embodiments, the first side panel 2 is L-shaped. The second side panel 3 is L-shaped.

[0055] In some embodiments, the first connecting portion 21 can be fixedly connected to the filament trough 6 in various ways. For example, both the first connecting portion 21 and the filament trough 6 are provided with mounting holes, and the first fastener 97 is used to mate with the mounting holes on the first connecting portion 21 and the mounting holes on the filament trough 6 to secure the first connecting portion 21 to the filament trough 6. In another example, the first connecting portion 21 can be connected to the filament trough 6 by snapping. In another example, the first connecting portion 21 can be welded to the filament trough 6 by spot welding, argon arc welding, laser welding, or other methods.

[0056] In some embodiments, the second connecting portion 31 can be fixedly connected to the filament trough 6 in various ways. For example, mounting holes can be provided on both the second connecting portion 31 and the filament trough 6, and the second fastener 98 can be used to engage the mounting holes on the second connecting portion 31 and the mounting holes on the filament trough 6 to secure the second connecting portion 31 to the filament trough 6. In another example, the second connecting portion 31 can be connected to the filament trough 6 by snapping. In another example, the second connecting portion 31 can be welded to the filament trough 6 by spot welding, argon arc welding, laser welding, or other methods.

[0057] Furthermore, along the width direction x of the first slit 4, the width of the hollow opening 61 is greater than the sum of the dimensions of the first cantilever 22 and the second cantilever 32. The difference between the width of the hollow opening 61 and the sum of the dimensions of the first cantilever 22 and the second cantilever 32 along the width direction x of the first slit 4 is related to the adjustable width range of the first slit 4.

[0058] Furthermore, the length of the first slit 4 is greater than the length of the first electron emitter 5 .

[0059] In some embodiments, roughness can be used to characterize the flatness of the first outer surface 221 or the second outer surface 321. It is understood that other parameters that can reflect the flatness can also be used to characterize the flatness of the first outer surface 221 or the second outer surface 321.

[0060] In some embodiments, the roughness of the first outer surface 221 is less than or equal to 0.2 μm, and / or the roughness of the second outer surface 321 is less than or equal to 0.2 μm. This makes the first outer surface 221 and / or the second outer surface 321 relatively smooth and shiny, reducing the thermal radiation absorption capacity of the first outer surface 221 and the second outer surface 321 while enhancing their reflective capacity. In other words, the first outer surface 221 and the second outer surface 321 can increase the amount of heat reflected from the first electron emitter 5, reducing the amount of heat absorbed by the first electron emitter 5, thereby reducing the power required by the first electron emitter 5 to maintain emission, which helps reduce the load power required by the hot cathode.

[0061] In some embodiments, the first side plate 2 can be polished so that the roughness of the first outer surface 221 is less than or equal to 0.2 μm. The second side plate 3 can be polished so that the roughness of the second outer surface 321 is less than or equal to 0.2 μm. The polishing can be mechanical polishing, chemical polishing, electrochemical polishing, etc.

[0062] Because the first side panel 2 and the second side panel 3 are separated and relatively independent, the first outer surface 221 of the first side panel 2 and the second outer surface 321 of the second side panel 3, which are separated and relatively independent, are easy to polish, reducing the roughness of the first outer surface 221 and the second outer surface 321, facilitating the cleaning required for high-vacuum components. This avoids problems such as surface roughness, cleaning difficulties, and sparking caused by difficult groove machining of the filament slot, thereby helping to extend the life of the X-ray tube.

[0063] In some embodiments, a first thermal insulation member is provided between the first connecting portion 21 and the filament trough 6 . The first thermal insulation member provided between the first connecting portion 21 and the filament trough 6 can reduce or even isolate the heat of the first electron emitter 5 from being transferred from the first connecting portion 21 to the filament trough 6 .

[0064] In some embodiments, a second thermal insulation member is provided between the second connecting portion 31 and the filament trough 6 . The second thermal insulation member provided between the second connecting portion 31 and the filament trough 6 can reduce or even isolate the heat of the first electron emitter 5 from being transferred from the second connecting portion 31 to the filament trough 6 .

[0065] In this way, the first and second thermal insulators further reduce the amount of heat absorbed by the filament trough 6 and focusing mask 1 from the first electron emitter 5, thereby further reducing the power required by the first electron emitter 5 to maintain emission, which helps reduce the load power required by the hot cathode. Furthermore, by reducing the amount of heat absorbed by the filament trough 6 from the first electron emitter 5, the amount of gas released by the filament trough 6 due to excessive temperature can also be reduced, preventing the gas from affecting the vacuum level of the X-ray tube and extending the service life of the X-ray tube.

[0066] The first thermal insulation member and the second thermal insulation member may be ceramic gaskets, or other components with thermal insulation function.

[0067] In practice, a potential difference exists between the filament trough 6 and the first electron emitter 5. In other words, a potential difference exists between the first slit 4 and the first electron emitter 5, ensuring that the first electron emitter 5 can properly emit electrons. To maintain the potential difference required for the first electron emitter 5 to emit electrons, the first cantilever 22 and the second cantilever 32 are electrically connected to the filament trough 6, ensuring that they are at the same potential as the filament trough 6. The filament trough 6 is a conductor.

[0068] There are multiple electrical connection methods to achieve electrical connection between the first cantilever 22 and the second cantilever 32 and the filament slot 6 .

[0069] In some embodiments, the first side plate 2 and the second side plate 3 are conductors, and the first cantilever 22 can be electrically connected to the filament trough 6 directly through the first side plate 2 to achieve electrical connection with the filament trough 6, and the second cantilever 32 can be electrically connected to the filament trough 6 through the second side plate 3.

[0070] In other embodiments, the electrical connection between the first cantilever 22 and the second cantilever 32 and the filament slot 6 is achieved through other conductors.

[0071] For example, if the first thermal insulation sheet and the second thermal insulation sheet are conductive, the first side plate 2 is electrically connected to the filament slot 6 via the first thermal insulation sheet, and the second side plate 3 is electrically connected to the filament slot 6 via the second thermal insulation sheet.

[0072] For another example, if the first and second thermal insulation sheets are insulated, the other conductors may be the first fastener 97 and the second fastener 98. The first connecting portion 21 and the filament trough 6 are electrically connected via the first fastener 97, thereby electrically connecting the first cantilever 22 and the filament trough 6. The second connecting portion 31 and the filament trough 6 are electrically connected via the second fastener 98, thereby electrically connecting the second cantilever 32 and the filament trough 6. It is understood that the other conductors may also be other electrically conductive components, and these examples are not listed here.

[0073] In some embodiments, the filament trough 6 is provided with a first guide portion, and the first side panel 2 is provided with a first mating portion. The first guide portion and the first mating portion are adapted to guide the first side panel 2 to move relative to the filament trough 6 along the width direction x of the first slit 4. And / or, the filament trough 6 is provided with a second guide portion, and the second side panel 3 is provided with a second mating portion. The second guide portion and the second mating portion are adapted to guide the second side panel 3 to move relative to the filament trough 6 along the width direction x of the first slit 4.

[0074] In some non-limiting embodiments, one of the first guiding portion and the first matching portion may be a guide groove, and the other may be a guide rail.

[0075] In a specific embodiment, the cathode assembly 100 further includes: a first supporting electrode column, a second supporting electrode column 94, a tube shell 95, and a flange 96. The first supporting electrode column 93 and the second supporting electrode column 94 are located in the cavity 11. The first supporting electrode column 93 and the second supporting electrode column 94 are respectively electrically connected to the first electron emitter 5 and support the first electron emitter 5 in the first slit 4. The first supporting electrode column 93 and the second supporting electrode column 94 are electrically disconnected when not connected to the first electron emitter 5.

[0076] The tube housing 95 partially extends into the cavity 11 and is connected to the filament trough 6. A flange 96 is located within the cavity 11 and is fixedly connected to the first supporting electrode column 93, the second supporting electrode column 94, the filament trough 6, and the tube housing 95. Specifically, one end of the flange 96 is connected to the filament trough 6, and the other end of the filament trough 6 is sealed to the tube housing 95.

[0077] In a specific implementation, the width of the first slit 4 ranges from 0.4 mm to 4 mm.

[0078] The material of the first side plate 2 is any one of the following: tungsten, molybdenum, rhenium, nickel, tungsten-containing alloys, molybdenum-containing alloys, rhenium-containing alloys, and nickel-containing alloys. The material of the second side plate 3 is any one of the following: tungsten, molybdenum, rhenium, nickel, tungsten-containing alloys, molybdenum-containing alloys, rhenium-containing alloys, and nickel-containing alloys. Tungsten, molybdenum, rhenium, nickel, tungsten-containing alloys, molybdenum-containing alloys, rhenium-containing alloys, and nickel-containing alloys have the characteristics of high temperature resistance, high melting point, and low saturated vapor pressure, which facilitates the thorough degassing of the first and second side plates 2 and 3 during the preparation of the X-ray tube, thereby reducing the probability of sparks caused by outgassing of the first and second side plates 2 and 3 during operation of the X-ray tube and improving the reliability and life of the X-ray tube.

[0079] The thickness of the first side plate 2 ranges from 1 mm to 3 mm. This helps ensure the strength of the first side plate 2 while making the first side plate 2 thinner, ensuring that it does not deform during the X-ray tube manufacturing process and at high temperatures during operation. It also minimizes space occupation and helps control the overall size of the cathode assembly 100.

[0080] The thickness of the second side plate 3 ranges from 1 mm to 3 mm. This helps ensure the strength of the second side plate 3 while making the second side plate 3 thinner, ensuring that it does not deform during the X-ray tube manufacturing process and at high temperatures during operation. It also minimizes space occupation and helps control the overall size of the cathode assembly 100.

[0081] In a specific implementation, the cathode assembly 100 may include an electron emitter. For example, as shown in FIG. 1 to FIG. 4 , the cathode assembly 100 includes a first electron emitter 5 .

[0082] When the cathode assembly 100 includes a first electron emitter 5 , the center plane of the first slit 4 coincides with the center plane of the filament slot 6 , thereby improving the focusing effect.

[0083] Furthermore, the central axis of the focusing mask 1 is coaxial with the central axis of the filament slot 6 .

[0084] It is understandable that the center plane of the first slit 4 and the center plane of the filament slot 6 may not coincide with each other, and they can be configured according to the focusing requirements.

[0085] In a specific implementation, the cathode assembly 100 may include a plurality of electron emitters, and the slit corresponding to each electron emitter may be obtained in a variety of ways.

[0086] In some embodiments, when a plurality of electron emitters are included, each electron emitter may correspond to a set of first side plates 2 and second side plates 3 , and corresponding slits may be formed by the first side plates 2 and the second side plates 3 .

[0087] In other embodiments, in conjunction with Figures 7 and 8 , two electron emitters (a first electron emitter 5 and a second electron emitter 91) are used as an example for illustration. The second side plate 3 also has a flat second inner surface 322 disposed opposite the second outer surface 321. The cathode assembly 100 also includes a third side plate 8 and a second electron emitter 91. The third side plate 8 is disposed within the cavity 11 and has a flat third outer surface 821 facing the second inner surface 322 and forming a second slit 92. The second electron emitter 91 is located within the second slit 92. Figure 7 is a schematic structural diagram of another cathode assembly of an X-ray tube according to an embodiment of the present invention; Figure 8 is a schematic partial structural diagram of point B in Figure 7 .

[0088] Furthermore, the roughness of the third outer surface 821 is less than or equal to 0.2 μm. The third side plate 8 may be polished to make the roughness of the third outer surface 821 less than or equal to 0.2 μm. The polishing may be mechanical polishing, chemical polishing, or electrochemical polishing.

[0089] Furthermore, the roughness of the second inner surface 322 is less than or equal to 0.2 μm. The second side plate 3 may be polished to make the roughness of the second inner surface 322 less than or equal to 0.2 μm. The polishing may be mechanical polishing, chemical polishing, or electrochemical polishing.

[0090] In a specific embodiment, the first side panel 2 includes a first connecting portion 21 and a first cantilever 22 that are connected to each other. The first connecting portion 21 is fixedly connected to the filament trough 6 and is located outside the hollow opening 61. The first cantilever 22 is bent relative to the first connecting portion 21 and extends into the hollow opening 61. The first outer surface 221 is located on the first cantilever 22.

[0091] The second side plate 3 is plate-shaped and connected to the filament slot 6 at both ends along the length direction y of the first slit 4 .

[0092] The third side panel 8 includes a third connecting portion 81 and a third cantilever 82 connected to each other. The third connecting portion 81 is fixedly connected to the filament trough 6 and located outside the hollow opening 61. The third cantilever 82 is bent relative to the third connecting portion 81 and extends into the hollow opening 61. The third outer surface 821 is located on the third cantilever 82. The second side panel 3 is located between the first side panel 2 and the third side panel 8.

[0093] The first side panel 2 and the third side panel 8 may both be L-shaped.

[0094] Furthermore, the third cantilever 82 has a third inner surface 822 arranged opposite to the third outer surface 821 , and a non-zero third gap 73 is defined between the third inner surface 822 and the second edge 612 .

[0095] In some embodiments, a first thermal insulator is disposed between the first connecting portion 21 and the filament trough 6. The first thermal insulator disposed between the first connecting portion 21 and the filament trough 6 can reduce or even isolate heat from the first electron emitter 5 from being transferred from the first connecting portion 21 to the filament trough 6.

[0096] In some embodiments, a third thermal insulation member is provided between the third connecting portion 81 and the filament trough body 6. The third thermal insulation member provided between the third connecting portion 81 and the filament trough body 6 can reduce or even isolate the heat of the second electron emitter 91 from being transferred from the third connecting portion 81 to the filament trough body 6.

[0097] In this way, the first and third thermal insulators can further reduce the absorption of heat from the first and second electron emitters 5, 91 by the filament trough 6 and the focusing shield 1, thereby further reducing the power required by the first and second electron emitters 5, 91 to maintain emission, which helps reduce the load power required by the hot cathode. Furthermore, by reducing the absorption of heat from the first and second electron emitters 5, 91 by the filament trough 6, the amount of gas released by the filament trough 6 due to excessive temperature can also be reduced, preventing the gas from affecting the vacuum level of the X-ray tube and extending the service life of the X-ray tube.

[0098] Furthermore, a second heat insulating member may be provided between the second side plate 3 and the filament trough 6. The second heat insulating member may reduce or even isolate the heat of the first electron emitter 5 and the second electron emitter 91 from being transferred from the second side plate 3 to the filament trough 6.

[0099] The first thermal insulation member and the third thermal insulation member may be ceramic gaskets, or other components with thermal insulation function.

[0100] In a specific implementation, the cathode assembly 100 may further include a third supporting electrode column and a fourth supporting electrode column. The third supporting electrode column and the fourth supporting electrode column are located in the cavity 11, and are electrically connected to the second electron emitter 91, respectively, to support the second electron emitter 91 in the second slit 92.

[0101] The width of the second slit 92 ranges from 0.4 mm to 4 mm.

[0102] The widths of the first slit 4 and the second slit 92 may be the same or different.

[0103] The first slit 4 and the second slit 92 may be located in the same plane or may not be located in the same plane.

[0104] The first slit 4 and the second slit 92 can be parallel or at a certain angle, and are configured according to actual focusing requirements.

[0105] The first slit 4 and the second slit 92 can be arranged symmetrically or asymmetrically, and are configured according to actual focusing requirements.

[0106] It should be noted that when the cathode assembly 100 includes three or more electron emitters, the number of side plates can be appropriately increased to form corresponding slits. The shape of the side plates can be adaptively adjusted according to actual needs.

[0107] In some embodiments, the focusing mask 1 has a mounting portion protruding into the cavity 11, and the first side plate 2 and the second side plate 3 are fixedly connected to the mounting portion. A hollow opening may be formed on the mounting portion.

[0108] The mounting portion may be an annular boss protruding toward the cavity 11 along the inner wall of the cavity 11 .

[0109] An embodiment of the present invention further provides an X-ray tube comprising: a housing, a cathode assembly, and an anode. Both the cathode assembly 100 and the anode are disposed within the housing. The cathode assembly 100 may be any of the aforementioned embodiments. The specific structure is described in the aforementioned embodiments and will not be further elaborated here.

[0110] It should be noted that the terms "first," "second," and "third" in the above-mentioned first slit, second slit, first electron emitter, second electron emitter, first connecting portion, second connecting portion, third connecting portion, first cantilever, second cantilever, third cantilever, first outer surface, second outer surface, third outer surface, first inner surface, second inner surface, and third inner surface are merely distinctions made for ease of description and do not limit the structure of the components. For example, the first slit and the second slit can be of the same size or of different sizes.

[0111] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A cathode assembly of an X-ray tube, characterized in that: include: A focusing mask, wherein the focusing mask has a cavity; A filament slot body is disposed in the cavity and connected to the focusing cover, and the filament slot body has a hollow opening; A first side plate is disposed in the cavity, the first side plate is fixedly connected to the filament slot, the first side plate has a flat first outer surface, and at least a portion of the first outer surface is located in the hollow opening; A second side plate is disposed in the cavity, the second side plate is fixedly connected to the filament slot body, the second side plate has a flat second outer surface, at least a portion of the second outer surface is located in the hollow opening, the second outer surface faces the first outer surface and forms a first slit, and the first side plate and the second side plate can move toward or away from each other; A first electron emitter is disposed in the first slit; Along the width direction of the first slit, the first side plate has a first inner surface arranged opposite to the first outer surface, the first inner surface faces the first edge of the hollow opening, and a non-zero first gap exists between the first inner surface and the first edge; And / or, along the width direction of the first slit, the second side plate has a second inner surface arranged opposite to the second outer surface, the second inner surface faces the second edge of the hollow opening, and a non-zero second gap exists between the second inner surface and the second edge; Wherein, the first edge and the second edge are arranged opposite to each other along the width direction of the first slit.

2. The cathode assembly according to claim 1, wherein: The first side plate includes a first connecting portion and a first cantilever connected to each other, the first connecting portion is fixedly connected to the filament slot body and is located outside the hollow opening, the first cantilever is bent relative to the first connecting portion and extends into the hollow opening, wherein the first outer surface is located on the first cantilever; The second side plate includes a second connecting portion and a second cantilever that are connected to each other, the second connecting portion is fixedly connected to the filament slot body and is located outside the hollow opening, the second cantilever is bent relative to the second connecting portion and extends into the hollow opening, wherein the second outer surface is located on the second cantilever.

3. The cathode assembly according to claim 2, wherein: The roughness of the first outer surface is less than or equal to 0.2 μm, and / or the roughness of the second outer surface is less than or equal to 0.2 μm.

4. The cathode assembly according to claim 2, wherein: A first heat insulating member is provided between the first connecting portion and the filament slot body; And / or, a second heat insulating member is provided between the second connecting portion and the filament slot body.

5. The cathode assembly according to claim 1, wherein: The second side plate further comprises a flat second inner surface arranged opposite to the second outer surface, and the cathode assembly further comprises: a third side plate, disposed in the cavity, the third side plate having a flat third outer surface, the third outer surface facing the second inner surface and forming a second slit; The second electron emitter is located in the second slit.

6. The cathode assembly according to claim 5, characterized in that The first side plate includes a first connecting portion and a first cantilever connected to each other, the first connecting portion is fixedly connected to the filament slot body and is located outside the hollow opening, the first cantilever is bent relative to the first connecting portion and extends into the hollow opening, wherein the first outer surface is located on the first cantilever; The second side plate is in a plate shape, and is connected to the filament slot body at both ends along the length direction of the first slit; The third side plate comprises a third connecting portion and a third cantilever connected to each other, the third connecting portion is fixedly connected to the filament slot body and is located outside the hollow opening, the third cantilever is bent relative to the third connecting portion and extends into the hollow opening, wherein the third outer surface is located on the third cantilever; Wherein, the second side panel is located between the first side panel and the third side panel.

7. The cathode assembly according to claim 1, wherein: The filament slot body is provided with a first guide portion, and the first side plate is provided with a first matching portion, the first guide portion is adapted to the first matching portion to guide the first side plate to move relative to the filament slot body along the width direction of the first slit; And / or, the filament slot body is provided with a second guide portion, the second side plate is provided with a second matching portion, the second guide portion is matched with the second matching portion to guide the second side plate to move relative to the filament slot body along the width direction of the first slit.

8. The cathode assembly according to claim 1, wherein: Also includes: A first supporting electrode column and a second supporting electrode column are located in the cavity, the first supporting electrode column and the second supporting electrode column are electrically connected to the first electron emitter respectively, and support the first electron emitter in the first slit; A tube shell partially extends into the cavity and is connected to the filament slot; The flange is located in the cavity and is fixedly connected to the first supporting electrode column, the second supporting electrode column, the filament slot body and the tube shell.

9. The cathode assembly according to claim 1, wherein: The width of the first slit is in the range of 0.4 mm to 4 mm.

10. An X-ray tube, characterized in that: include: shell; The cathode assembly according to any one of claims 1 to 9, disposed in the housing; The anode is arranged in the shell.

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