Ceramic voltage-resistant electrode structure for inhibiting field emission
By setting up a protruding control electrode near the three intersection points to connect to the cathode, the potential change at the three intersection points is reduced, and the electron escape problem caused by excessive electric field in the X-ray tube is solved, the probability of ignition is reduced, processing is simplified, and the yield rate is improved.
Patent Information
- Application Number
- CN202422533284.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-21
- Publication Date
- 2025-08-08
- Estimated Expiration
- 2034-10-21
AI Technical Summary
In the prior art, excessive electric field at the three intersection points leads to electron escape and form a secondary electron multiplication effect, causing X-ray tube to discharge and ignite, and the complex surface structure increases the difficulty of processing, reduces the yield rate, which is not conducive to large-scale production.
A protruding control electrode is arranged near the three intersection points, connected to the cathode to the same potential, reducing the potential change at the three intersection points and suppressing electron field emission.
It effectively reduces the electric field strength, reduces the probability of ignition, simplifies the processing process, and improves the yield rate.
Smart Images
Figure CN223206217U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of voltage-resistant ceramic structures, in particular to a ceramic voltage-resistant electrode structure capable of suppressing field emission. Background Art
[0002] The X-ray tube is the core component for generating X-rays in industrial CT. X-ray penetrating power is positively correlated with X-ray energy, and the voltage between the cathode and anode of the X-ray tube directly determines the energy of the X-ray. High-voltage ceramic metal X-ray tubes are designed to meet the current industrial demand for increasing penetrating power. Typically, the single-ended voltage (the voltage between the cathode and anode) reaches over 160kV and can exceed 450kV.
[0003] In X-ray tubes, the cathode and anode are insulated with voltage-resistant ceramic. Insufficient insulation performance will cause the electric field at the cathode-ceramic-vacuum triple intersection (hereinafter referred to as the triple intersection) to be too strong, causing electrons to escape from the metal. The escaping electrons bombard the ceramic to form secondary electrons, and through the secondary electron multiplication effect, a conductive path is formed between the cathode and anode, causing spark discharge, resulting in X-ray tube failure. To increase the voltage resistance, the most direct method is to increase the volume of the ceramic and increase the insulation distance between the electrodes. However, as the voltage reaches 160kV, the method of increasing the insulation distance has increasingly lower engineering benefits. Not only does the improvement in insulation performance per unit increase in insulation distance decrease, but it also significantly increases the volume and weight of the X-ray tube.
[0004] For high-voltage ceramic-metal X-ray tubes, the industry usually considers improvement plans from two aspects: voltage-resistant materials and voltage-resistant structures. In terms of voltage-resistant structures, the method of adding corrugations or protrusions to the flat ceramic surface to increase the surface polarity of the ceramic is usually adopted to increase the electron conduction path and improve the voltage resistance. However, these methods do not solve the voltage resistance problem from the root cause of discharge and sparking, that is, they do not suppress the electron emission phenomenon at the cathode.
[0005] The conventional solution of increasing the surface conductive path of voltage-resistant ceramics cannot solve the problem of ceramic voltage resistance from the root. If the electric field at the three intersections is too strong and the number of emitted electrons is large enough, it can still form an electron conductive path on the ceramic surface through the secondary electron multiplication effect to cause discharge and sparking. On the other hand, the complex surface structure will increase the complexity of ceramic material processing, reduce the yield, and is not conducive to large-scale production. Therefore, certain improvements are needed. Utility Model Content
[0006] The purpose of the present utility model is to solve the problem in the prior art that if the electric field at the triple intersection is too strong and the number of emitted electrons is large enough, an electron conduction path can be formed on the ceramic surface through the secondary electron multiplication effect to cause discharge and sparking. On the other hand, the complex surface structure will increase the complexity of ceramic material processing, reduce the yield, and be unfavorable for large-scale production. A ceramic withstand voltage electrode structure that suppresses field emission is proposed.
[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:
[0008] A ceramic voltage-resistant electrode structure for suppressing field emission comprises an anode, a cathode is arranged on one side of the anode, a voltage-resistant ceramic is arranged between the cathode and the anode, a control electrode is arranged on one side of the voltage-resistant ceramic, and one side of the control electrode is connected to the cathode.
[0009] As a further description of the above technical solution:
[0010] The anode and cathode are both made of metal and are separated by pressure-resistant ceramic.
[0011] As a further description of the above technical solution:
[0012] Three intersection points are arranged at the intersections of the pressure-resistant ceramic, the cathode and the external environment.
[0013] As a further description of the above technical solution:
[0014] The control electrode is arranged near the three-intersection position, and the control electrode is arranged in a protruding manner.
[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0016] 1. In the present invention, a control electrode is provided, and since the control electrode is connected to the cathode, the cathode and the control electrode have the same potential, so as to reduce the potential change at the three intersections, reduce the electric field effect of the ceramic withstand voltage electrode structure during use, and suppress electron field emission, thereby reducing the probability of ignition of the ceramic withstand voltage electrode structure during use. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a structural diagram of the utility model;
[0018] Figure 2 This is a schematic diagram of the electric field simulation structure of the three intersections without the control electrodes in the present invention;
[0019] Figure 3 This is a schematic diagram of the electric field simulation structure at the three intersections of the loading control electrodes of the utility model;
[0020] Figure 4 This is a schematic diagram of the traditional pressure-resistant ceramic structure in the utility model.
[0021] Legend:
[0022] 1. Anode; 2. Cathode; 3. Voltage-resistant ceramic; 4. Triple intersection; 5. Control electrode. DETAILED DESCRIPTION
[0023] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0024] See also Figures 1-4 The utility model provides a technical solution: a ceramic voltage-resistant electrode structure for suppressing field emission, including an anode 1, a cathode 2 is provided on one side of the anode 1, a voltage-resistant ceramic 3 is provided between the cathode 2 and the anode 1, a control electrode 5 is provided on one side of the voltage-resistant ceramic 3, and one side of the control electrode 5 is connected to the cathode 2. The anode 1 and the cathode 2 are both made of metal, and the anode 1 and the cathode 2 are separated by the voltage-resistant ceramic 3. A three-intersection point 4 is provided at the intersection of the voltage-resistant ceramic 3, the cathode 2 and the external environment, the control electrode 5 is provided near the three-intersection point 4, and the control electrode 5 is configured to be protruding.
[0025] Specific implementation method: The entire ceramic voltage-resistant electrode structure is connected to an external power supply device. At this time, due to the different dielectric constants of the ceramic material and the external environment in the traditional ceramic voltage-resistant electrode structure, and the small rounded corners at the edge of the ceramic material and the small gaps between the metal, the electric field is concentrated at this location. Therefore, the electric field near the triple intersection is usually stronger than at other locations, which easily causes electrons to escape from the cathode surface. In engineering, it is generally believed that the field strength is close to 1×10 7 V / m has a greater risk of ignition. This structure and the general structure are simulated. Both simulations use the same boundary conditions. The voltage between the anode 1 and the cathode 2 is 140kV, and the withstand voltage distance of the pressure-resistant ceramic 3 is 80mm. Figure 3 It can be seen that the electric field strength is about 3.8×10 6 , and this structure is as Figure 4 It can be seen that the structural difference is only the addition of a control electrode 5 near the cathode 2. Since the control electrode 5 is connected to the cathode 2, the cathode 2 and the control electrode 5 have the same potential, and the electric field strength is about 2.6×10 6, reduced by about 32%, helping to reduce the potential change of the triple intersection 4, thereby reducing the effect of the electric field to suppress electron field emission, thereby reducing the probability of sparking of the ceramic voltage-resistant electrode structure during use.
[0026] Working principle: When in use, the ceramic voltage-resistant electrode structure is connected to an external power supply device. This structure and the general structure are simulated. Both simulations use the same boundary conditions. The voltage between the anode 1 and the cathode 2 is 140kV, and the voltage-resistant distance of the voltage-resistant ceramic 3 is 80mm. Figure 3 It can be seen that the electric field strength is about 3.8×10 6 , and this structure is as Figure 4 It can be seen that the structural difference is only the addition of a control electrode 5 near the cathode 2. Since the control electrode 5 is connected to the cathode 2, the cathode 2 and the control electrode 5 have the same potential, and the electric field strength is about 2.6×10 6 , reduced by about 32%, which assisted in reducing the potential change of the triple intersection 4, thereby reducing the electric field effect of the structure during use.
[0027] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A ceramic withstand voltage electrode structure for suppressing field emission, comprising an anode (1), characterized in that: A cathode (2) is provided on one side of the anode (1), a pressure-resistant ceramic (3) is provided between the cathode (2) and the anode (1), a control electrode (5) is provided on one side of the pressure-resistant ceramic (3), and one side of the control electrode (5) is connected to the cathode (2).
2. The ceramic withstand voltage electrode structure for suppressing field emission according to claim 1, characterized in that: The anode (1) and cathode (2) are both made of metal, and the anode (1) and cathode (2) are separated by a pressure-resistant ceramic (3).
3. The ceramic withstand voltage electrode structure for suppressing field emission according to claim 2, characterized in that: Three intersection points (4) are provided at the intersection positions of the pressure-resistant ceramic (3), the cathode (2) and the external environment.
4. The ceramic withstand voltage electrode structure for suppressing field emission according to claim 3, characterized in that: The control electrode (5) is arranged near the three-intersection point (4), and the control electrode (5) is arranged in a protruding manner.