An X-ray generating device with switchable focal point

Abstract

The X-ray generating device with switchable focus of the present invention includes a high-voltage power supply and an X-ray tube. The X-ray tube is disposed at one end of the high-voltage power supply and includes a cathode assembly, an anode assembly, an electron beam focusing assembly, a housing assembly, and a vacuum assembly. The cathode assembly includes a replaceable cathode unit, which is a lanthanum hexaboride cathode or a zirconium oxide tungsten cathode. By setting the replaceable cathode unit to a lanthanum hexaboride cathode or a zirconium oxide tungsten cathode, free switching between microfocus mode and nanofocus mode is achieved, enabling high resolution and high power output on the same device, and simultaneously meeting the high-precision inspection requirements of chip packaging and the high-power inspection requirements of circuit boards, batteries, etc.

Description

Technical Field

[0001] This invention relates to the field of X-ray imaging technology, and more specifically, to an X-ray generating device with switchable focus. Background Technology

[0002] As the core X-ray radiation source, the X-ray tube generates high-energy X-rays to achieve non-destructive testing of the internal structure of objects. It is currently widely used in medical diagnosis, security inspection, and industrial non-destructive testing. Its basic working principle is as follows: the cathode emits electrons under heating or an electric field. The high-voltage electric field between the cathode and anode accelerates the electron beam. After deflection and focusing, the accelerated electron beam is finally struck at high speed on the anode target surface. The high-energy electrons interact with the target material, primarily generating X-rays through bremsstrahlung. To ensure continuous and stable emission and precise control of the electron beam, the X-ray tube typically uses a high-voltage power supply to provide a stable cathode-anode electric field and a vacuum chamber to provide a high-vacuum environment, avoiding scattering and energy loss caused by collisions between electrons and gas molecules. Currently, X-ray tubes usually need to work in conjunction with a high-voltage power supply to form a complete X-ray emitting device. Common open-type microfocus X-ray tubes often adopt a split structure, connecting the tube to an external high-voltage power supply via a high-voltage cable.

[0003] In the field of open X-ray sources, relatively mature product series already exist abroad, and some domestic companies have successfully developed 160 kV-level open X-ray sources. However, existing domestic products are mainly based on microfocus mode, with an image resolution as low as approximately 0.9 μm. As global semiconductor packaging technology advances towards advanced packaging (such as 2.5D / 3D packaging, System-in-Package (SiP), and High-Bandwidth Memory (HBM), inspection demands are becoming increasingly stringent, placing higher requirements on X-ray inspection technology for high resolution, non-destructive testing, and dynamic analysis. While mature foreign products can achieve image resolutions up to 0.5 μm, there are no similar mature products in China, and the industry relies heavily on imports. It is worth noting that most of these imported products are closed-loop structures with relatively low maximum output power, primarily suitable for low-power inspection scenarios such as chip packaging. For inspection objects requiring higher penetration and power, such as printed circuit boards (PCBs), power batteries, and composite materials, existing closed-loop X-ray tubes are limited by the emission current of the electron gun cathode and the maximum operating voltage of the X-ray tube, making it difficult to simultaneously achieve high resolution and high power output.

[0004] In addition, the following prominent problems exist in the current procurement and use of nondestructive testing equipment in China: First, imported equipment is expensive and has a long delivery cycle; second, equipment debugging and maintenance are difficult and after-sales service response is not timely; third, due to the lack of localized maintenance capabilities, equipment usually needs to be returned to the factory for repair after failure, which takes a long time; fourth, different application scenarios often require different models of X-ray sources, which increases the cost of equipment purchase and the complexity of use. Summary of the Invention

[0005] In view of the problems existing in the prior art described above, this application provides an X-ray generating device with switchable focus, which can solve the technical problems that existing X-ray generating devices are unable to achieve both high resolution and high power output, and cannot adapt to different detection needs with a single device.

[0006] To achieve the above and other related objectives, the present invention provides a focus-switching X-ray generating device, including a high-voltage power supply and a ray tube, wherein the ray tube is disposed at one end of the high-voltage power supply, and includes:

[0007] The cathode assembly includes a replaceable cathode unit, which is a lanthanum hexaboride cathode or a zirconium oxytungsten cathode.

[0008] An anode assembly, located above the cathode assembly, includes a transmission target and an aperture. The aperture has an aperture opening. The electron emission center of the cathode unit, the center of the aperture opening, and the center of the transmission target are coaxially arranged.

[0009] An electron beam focusing assembly is disposed between the cathode assembly and the anode assembly and is used to focus the electron beam emitted by the cathode unit;

[0010] The outer casing assembly covers the outside of the cathode assembly and is located above the high-voltage power supply, forming a sealed cavity together with the high-voltage power supply and the electron beam focusing assembly;

[0011] A vacuum assembly is connected to a sealed cavity to maintain the vacuum environment within the sealed cavity.

[0012] Optionally, the vacuum assembly includes:

[0013] A vortex pump is located on one side of the housing assembly and is connected to the sealed cavity via a vacuum tube;

[0014] An ion pump is located on one side of the housing assembly and is connected to the sealed cavity via a vacuum tube;

[0015] An oxygen-free copper gasket is placed between the sealed cavity and the electron beam focusing assembly.

[0016] Optionally, the transmission target is a diamond transmission target, including a replaceable first target and a second target. The first target is a high-resolution diamond target adapted to a zirconium tungsten oxide cathode, and the second target is a high-power diamond target adapted to a lanthanum hexaboride cathode.

[0017] Optionally, the cathode assembly also includes:

[0018] The ceramic component is located at one end of the high-voltage power supply.

[0019] A gate is disposed on the emission side of the cathode unit;

[0020] A semiconductor component is disposed between a ceramic component and a gate.

[0021] Optionally, the electron beam focusing assembly includes:

[0022] An electrode shoe is disposed around the cathode assembly and the anode assembly to form a mounting portion;

[0023] The focusing coil is located in the mounting section.

[0024] Optionally, the focusing coil has fewer than 800 turns, and the pole shoes are made of electromagnetic soft iron material with a machining precision at the submicron level.

[0025] Optionally, the X-ray generating device further includes an O-ring, disposed between the transmission target and the electron beam focusing assembly.

[0026] Optionally, the high-voltage power supply and the X-ray tube are integrated into one unit.

[0027] Optionally, the maximum operating voltage of the X-ray tube is between 200 kV and 250 kV.

[0028] Optionally, the X-ray generating apparatus further includes a control system, which is communicatively connected to the cathode assembly and the user interface of the X-ray generating apparatus to automatically detect the type of the currently installed cathode unit and automatically switch the corresponding focus mode control parameters on the user interface based on the detection results.

[0029] As described above, the X-ray generating device with switchable focus provided by the present invention has at least the following beneficial technical effects:

[0030] The X-ray generating device with switchable focus of the present invention includes a high-voltage power supply and an X-ray tube. The X-ray tube is disposed at one end of the high-voltage power supply and includes a cathode assembly, an anode assembly, an electron beam focusing assembly, a housing assembly, and a vacuum assembly. The cathode assembly includes a replaceable cathode unit, which is a lanthanum hexaboride cathode or a zirconium oxide tungsten cathode. By setting the replaceable cathode unit to a lanthanum hexaboride cathode or a zirconium oxide tungsten cathode, free switching between microfocus mode and nanofocus mode is achieved. It can achieve both high resolution and high power output on the same device. In microfocus mode, the system resolution can reach 1μm and the maximum power can reach 50W. In nanofocus mode, the system resolution can reach 0.1μm, which can simultaneously meet the high-precision inspection requirements of chip packaging and the high-power inspection requirements of circuit boards, batteries, etc.

[0031] The anode assembly of this invention is disposed above the cathode assembly and includes a transmission target and an aperture. The aperture has an aperture opening. The electron emission center of the cathode unit, the center of the aperture opening, and the center of the transmission target are coaxially aligned. This eliminates the need for traditional magnetic deflection systems, achieving extremely high physical alignment. After assembly, no optical path alignment adjustment is required, effectively reducing the size and weight of the X-ray tube. An electron beam focusing assembly is disposed between the cathode and anode assemblies to focus the electron beam emitted by the cathode unit. A housing assembly covers the cathode assembly and is located above the high-voltage power supply, forming a sealed cavity together with the high-voltage power supply and the electron beam focusing assembly. A vacuum assembly communicates with the sealed cavity to maintain a vacuum environment within the cavity.

[0032] This invention achieves a detachable sealing structure using oxygen-free copper gaskets and metal O-rings, allowing for convenient replacement and maintenance of both the cathode unit and the transmission target, thus solving the problems of difficult and time-consuming maintenance in traditional equipment. By optimizing the three-junction structure by placing semiconductor components between the ceramic component and the gate, the problems of charge accumulation and ceramic surface creepage are effectively solved, ensuring the stability of the X-ray tube during long-term operation.

[0033] The high-voltage power supply and X-ray tube of this invention are integrated into one structure, which is small in size and light in weight, and has no directional or positional requirements for installation, further improving the integration and ease of use of the equipment. Attached Figure Description

[0034] Figure 1 The diagram shown is a structural schematic of an X-ray generating device provided in an embodiment of the present invention.

[0035] Figure 2 Displayed as Figure 1 A cross-sectional view from the perspective of AA.

[0036] Figure Labels

[0037] 1. X-ray tube; 11. Cathode assembly; 111. Cathode unit; 112. Ceramic component; 113. Grid; 114. Semiconductor component; 12. Anode assembly; 121. Transmission target; 122. Aperture; 1221. Aperture aperture; 13. Electron beam focusing assembly; 131. Polar shoe; 1311. Mounting part; 132. Focusing coil; 14. Housing assembly; 141. Sealed cavity; 15. Vacuum assembly; 151. Vortex pump; 152. Ion pump; 153. Oxygen-free copper gasket; 154. Vacuum tube; 2. O-ring seal; 3. High voltage power supply. Detailed Implementation

[0038] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0039] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Although the illustrations only show components related to the present invention and are not drawn according to the actual number, shape and size of the components, the shape, quantity, positional relationship and proportion of each component can be arbitrarily changed under the premise of realizing the technical solution of this invention, and the layout of the components may also be more complex.

[0040] This embodiment provides an X-ray generating device with switchable focus, see reference. Figure 1 and Figure 2 It includes a high-voltage power supply 3 and an X-ray tube 1, with the X-ray tube 1 disposed at one end of the high-voltage power supply 3. In this embodiment, the high-voltage power supply 3 and the X-ray tube 1 are an integral structure.

[0041] Reference Figure 1 and Figure 2 Specifically, the high-voltage power supply 3 is solid-state encapsulated with epoxy resin. The high-voltage power supply 3 provides negative high voltage to the X-ray tube 1, while the filament voltage and grid voltage are suspended above the high voltage and connected to the grid high-voltage wire through the filament high-voltage wire. This integrated structure combined with solid-state encapsulation makes the entire X-ray generating device oriented and position-independent during installation, significantly improving the integration and ease of use of the X-ray generating device.

[0042] Continue to refer to Figure 1 and Figure 2In this embodiment, the maximum operating voltage of the X-ray tube 1 is between 200 kV and 250 kV. In an optional embodiment of this embodiment, the maximum operating voltage of the X-ray tube 1 is 225 kV. The X-ray tube 1 includes a cathode assembly 11, an anode assembly 12, an electron beam focusing assembly 13, a housing assembly 14, and a vacuum assembly 15.

[0043] Reference Figure 1 and Figure 2 The cathode assembly 11 includes replaceable cathode units 111, which are either lanthanum hexaboride cathodes or zirconium oxide tungsten cathodes. Lanthanum hexaboride cathodes, as the thermal emission source, have higher brightness, a smaller emission plane, longer lifespan, and more stable emission characteristics, making them suitable for microfocus mode. Zirconium oxide tungsten cathodes have a smaller emission plane, higher brightness, and more stable emission, making them suitable for nanofocus mode. By replacing different cathode units, the X-ray generator of this embodiment can freely switch between microfocus and nanofocus operating modes according to actual detection needs. It can achieve both high resolution and high power output on the same device. In microfocus mode, the system resolution can reach 1μm and the maximum power can reach 50W, while in nanofocus mode, the system resolution can reach 0.1μm, simultaneously meeting the high-precision detection needs of chip packaging and the high-power detection needs of circuit boards, batteries, etc.

[0044] Reference Figure 1 and Figure 2 The cathode assembly 11 also includes a ceramic component 112, a grid 113, and a semiconductor component 114. The ceramic component 112, located at one end of the high-voltage power supply 3, is made of high-performance alumina ceramic material and features low outgassing rate, high insulation performance, and strong resistance to surface creepage. The grid 113 is located on the emission side of the cathode unit 111 and is used to control the emission and cutoff of the electron beam. The semiconductor component 114 is located between the ceramic component 112 and the grid 113, and its function is to optimize the electric field distribution at the three-junction point formed by the grid 113, the ceramic component 112, and the vacuum environment. Specifically, during long-term operation of the X-ray tube, charge accumulation easily occurs on the surface of the ceramic component 112 at this three-junction point. When the accumulation reaches a certain level, it triggers a momentary discharge, initiating the power supply protection mechanism. The semiconductor component 114 divides the three-junction point, enabling timely conduction of accumulated charge, effectively solving the surface creepage and discharge problems of the ceramic component 112, thereby ensuring the stability and continuity of the X-ray tube 1's operation.

[0045] Preferably, in the cathode assembly 11, to eliminate non-uniformity factors in the high-voltage electric field, the surface of the structural components involved in the high-voltage section of the cathode undergoes a special high-gloss treatment. This treatment, through precision machining and surface finishing processes, minimizes microscopic defects such as burrs, protrusions, and scratches on the surface of the structural components, thereby effectively suppressing local electric field distortion and tip discharge phenomena caused by surface defects, improving the electric field uniformity and high-voltage stability in the cathode assembly 11 region, and further ensuring the reliability of electron beam emission and the long-term operational stability of the X-ray tube 1.

[0046] Continue to refer to Figure 1 and Figure 2 The anode assembly 12 is positioned above the cathode assembly 11 and includes a transmission target 121 and an aperture 122. The aperture 122 has an aperture opening 1221. The function of the aperture 122 is to remove stray electrons that are far from the optical axis, preventing them from affecting the focal spot size and target efficiency, and ensuring that only the electron beam passing through the aperture opening 1221 can ultimately bombard the transmission target 121. To achieve optimal electron optical performance, the X-ray generating device in this embodiment abandons the traditional magnetic deflection system in its design, instead using ultra-high precision structural components to ensure extremely high physical alignment. Specifically, the electron emission center of the cathode unit 111, the center of the aperture opening 1221, and the center of the transmission target 121 are coaxially arranged, eliminating the need for optical path alignment adjustment after assembly. This design ensures accurate electron beam bombardment of the target surface while significantly reducing the size and mass of the X-ray tube 1.

[0047] In this embodiment, the transmission target 121 is a diamond transmission target, including a replaceable first target material and a second target material. The first target material is a high-resolution diamond target adapted to a zirconium tungsten oxide cathode, used to achieve extreme resolution in nanofocus mode. The second target material is a high-power diamond target adapted to a lanthanum hexaboride cathode, used to withstand higher power (up to 50W) electron beam bombardment in microfocus mode, to meet the detection requirements of samples such as circuit boards and batteries.

[0048] Reference Figure 1 and Figure 2An electron beam focusing assembly 13 is disposed between the cathode assembly 11 and the anode assembly 12 to focus the electron beam emitted by the cathode unit 111. Specifically, the electron beam focusing assembly 13 includes a pole piece 131 and a focusing coil 132. The pole piece 131 is disposed around the cathode assembly 11 and the anode assembly 12, forming a mounting portion 1311. The focusing coil 132 is disposed on the mounting portion 1311, and the focusing coil 132 and the pole piece 131 together constitute a magnetic focusing lens. When the electron beam reaches the position of the focusing coil 132, the electron beam can be focused, and only a portion of it ultimately reaches the transmission target 121 through the aperture 1221 on the aperture 122. To minimize the astigmatism of the magnetic focusing lens, in this embodiment, the number of turns of the focusing coil 132 is less than 800 turns, thereby effectively controlling the accuracy of the winding of the focusing coil 132. At the same time, the pole piece 131 is made of high-performance electromagnetic soft iron material, and its processing accuracy is at the sub-micron level. This high-precision focusing assembly ensures that the electron beam is precisely focused, ultimately forming the desired tiny focal spot on the transmission target 121.

[0049] The outer casing assembly 4 is covered outside the cathode assembly 11 and located above the high voltage power supply 3, forming a sealed cavity 141 together with the high voltage power supply 3 and the electron beam focusing assembly 13.

[0050] The vacuum assembly 15 is connected to the sealed cavity 141 to maintain the vacuum environment of the sealed cavity 141. Specifically, the vacuum assembly 15 in this embodiment includes a vortex pump 151, an ion pump 152, and an oxygen-free copper gasket 153.

[0051] Reference Figure 1 and Figure 2 Specifically, a vortex pump 151 is located on one side of the housing assembly 14 and is connected to the sealed cavity 141 via a vacuum tube 154, used for rough evacuation of the X-ray tube 1. An ion pump 152 is located on one side of the housing assembly 14 and is connected to the sealed cavity 141 via a vacuum tube 154, used to activate after the rough evacuation reaches a certain pressure, together reducing the internal pressure of the sealed cavity 141 to 10. -8 Ultra-high vacuum at the Pa level. An oxygen-free copper gasket 153 is disposed between the sealed cavity 141 and the electron beam focusing assembly 13. When the cathode unit 111 needs to be replaced, the part above the oxygen-free copper gasket 153, including the electron beam focusing assembly 13 and the anode assembly 12, can be removed for replacement. After the replacement, a new oxygen-free copper gasket 153 needs to be installed, and then the assembly can be reinstalled.

[0052] Reference Figure 1 and Figure 2The X-ray generator with switchable focus in this embodiment also includes an O-ring 2, disposed between the transmission target 121 and the electron beam focusing assembly 13, for sealing the connection between the two components. The O-ring 2 is a metal O-ring. The design of the O-ring 2 and the oxygen-free copper gasket 153 allows for easy disassembly, replacement, and maintenance of key components such as the cathode unit 111 and the transmission target 121, significantly reducing the maintenance cost and cycle of the X-ray generator.

[0053] The X-ray generating device with switchable focus in this embodiment also includes a control system, which is communicatively connected to the cathode assembly 11 and the user interface of the X-ray generating device to automatically detect the type of the currently installed cathode unit 111 and automatically switch the corresponding focus mode control parameters on the user interface according to the detection results. For example, it automatically adjusts the excitation current of the focusing coil 132, the output parameters of the high-voltage power supply 3, etc., to ensure that the X-ray tube 1 can be put into operation in the optimal state immediately after the cathode unit 111 is replaced.

[0054] Reference Figure 1 and Figure 2 In this embodiment, the X-ray generating device achieves free switching between microfocus mode (lanthanum hexaboride cathode) and nanofocus mode (zirconium tungsten oxide cathode) through a replaceable cathode unit 111, solving the technical challenge of a single device being unable to simultaneously achieve high resolution and high power output. The anode assembly 12 abandons the traditional magnetic deflection system, adopting a design where the cathode electron emission center, aperture center, and transmission target center are strictly coaxial, significantly reducing the overall size while ensuring precise electron beam bombardment. The semiconductor component 114 in the cathode assembly effectively optimizes the electric field distribution at the three junction points, solving the problems of charge accumulation and surface creepage, ensuring the long-term stable operation of the X-ray tube. The vacuum system composed of the vortex pump 151 and ion pump 152, along with the oxygen-free copper gasket 153 and O-ring seal 2, achieves a semi-enclosed, detachable structure, allowing for convenient replacement and maintenance of both the cathode unit and the transmission target. The high-voltage power supply 3 and the X-ray tube 1 are integrated into a single structure, small in size and light in weight, with no directional restrictions on installation, greatly improving the integration and ease of use of the equipment.

[0055] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A focus-switching X-ray generating device, characterized in that, Includes a high-voltage power supply and an X-ray tube, wherein the X-ray tube is disposed at one end of the high-voltage power supply, and includes: A cathode assembly, including a replaceable cathode unit, said cathode unit being a lanthanum hexaboride cathode or a zirconium tungsten oxide cathode; An anode assembly, disposed above the cathode assembly, includes a transmission target and an aperture. The aperture has an aperture opening. The electron emission center of the cathode unit, the center of the aperture opening, and the center of the transmission target are coaxially arranged. An electron beam focusing assembly is disposed between the cathode assembly and the anode assembly for focusing the electron beam emitted by the cathode unit; The outer casing assembly covers the outside of the cathode assembly and is located above the high-voltage power supply, forming a sealed cavity together with the high-voltage power supply and the electron beam focusing assembly; A vacuum assembly is connected to the sealed cavity to maintain the vacuum environment of the sealed cavity.

2. The X-ray generating device with switchable focus according to claim 1, characterized in that, The vacuum assembly includes: A vortex pump is disposed on one side of the housing assembly and is connected to the sealed cavity via a vacuum tube; An ion pump is located on one side of the housing assembly and is connected to the sealed cavity via a vacuum tube; An oxygen-free copper gasket is disposed between the sealed cavity and the electron beam focusing assembly.

3. The X-ray generating device with switchable focus according to claim 1, characterized in that, The transmission target is a diamond transmission target, including a replaceable first target material and a second target material. The first target material is a high-resolution diamond target adapted to the zirconium tungsten oxide cathode, and the second target material is a high-power diamond target adapted to the lanthanum hexaboride cathode.

4. The X-ray generating device with switchable focus according to claim 1, characterized in that, The cathode assembly also includes: A ceramic component is disposed at one end of the high-voltage power supply; A gate is disposed on the emission side of the cathode unit; A semiconductor device is disposed between the ceramic device and the gate.

5. The X-ray generating device with switchable focus according to claim 1, characterized in that, The electron beam focusing assembly includes: An electrode shoe is disposed around the cathode assembly and the anode assembly to form a mounting portion; A focusing coil is disposed in the mounting portion.

6. The X-ray generating device with switchable focus according to claim 5, characterized in that, The focusing coil has fewer than 800 turns, and the pole piece is made of electromagnetic soft iron material with a processing precision at the submicron level.

7. The X-ray generating device with switchable focus according to claim 5, characterized in that, Also includes: An O-ring is disposed between the transmission target and the electron beam focusing assembly.

8. The X-ray generating device with switchable focus according to claim 1, characterized in that, The high-voltage power supply and the ray tube are an integrated structure.

9. The X-ray generating device with switchable focus according to claim 1, characterized in that, The maximum operating voltage of the ray tube is between 200 kV and 250 kV.

10. The X-ray generating device with switchable focus according to claim 1, characterized in that, Also includes: The control system is communicatively connected to the user interface of the cathode assembly and the X-ray generator to automatically detect the type of the currently installed cathode unit and automatically switch the corresponding focus mode control parameters on the user interface based on the detection results.

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