Vacuum capacitor capable of accurately controlling capacitance value

Abstract

The invention discloses a vacuum capacitor capable of accurately controlling a capacitance value, which comprises a shell, two electrode discs and two electrode groups, and is characterized in that the two electrode discs are respectively connected to two ends of the shell in a sealing manner so as to form a vacuum cavity in the shell; the two electrode sets are fixedly connected to the two electrode discs in a one-to-one correspondence mode, and meanwhile the two electrode sets are contained in the vacuum cavity in a mutually coupled mode. At least one of the two electrode plates is in sealed connection with the shell through a connecting piece, the connecting piece is provided with a deformation part, and when axial acting force is applied to the vacuum capacitor, the connecting piece is stressed to enable the deformation part to deform, so that the length of the connecting piece in the axial direction is increased or reduced, and the vacuum capacitor is more compact. Therefore, the distance between the electrode disc connected with the connecting piece and the shell is changed, and the coupling area between the two electrode sets is controlled. According to the invention, the coupling area between the two electrode groups can be regulated and controlled, the accurate adjustment of the capacitance value is realized, and the requirement of semiconductor manufacturing equipment on the accurate capacitance value of the vacuum capacitor is met.

Description

Technical Field

[0001] The invention relates to the technical field of capacitors, and in particular to a vacuum capacitor capable of accurately controlling capacitance. Background Art

[0002] A vacuum capacitor is a capacitor with ceramic as the insulating shell, vacuum as the medium, and high-conductivity oxygen-free copper material as the electrode. Compared with other capacitors, it has the characteristics of high voltage resistance, large carrying current, low high-frequency loss, and self-healing after instantaneous overload, which is particularly suitable for high-frequency and high-voltage applications. At present, vacuum capacitors have been widely used in broadcast transmission, medical magnetic resonance imaging, high-frequency heating, semiconductor etching, plasma cleaning and other equipment. In these high-frequency devices, vacuum capacitors form a resonant circuit with high-frequency inductors to complete high-frequency impedance matching and achieve stable transmission of RF power.

[0003] Traditional fixed capacitance vacuum capacitors follow the national standard and the yield limit of the production process. The nominal capacitance accuracy is generally set to ±5% or ±10% of the nominal capacitance. If the accuracy is to be further improved, precision sorting must be performed at the expense of yield, which increases the cost of the capacitor accordingly. However, with the continuous improvement of capacitor accuracy requirements in the semiconductor field, the accuracy requirements for the nominal capacitance value of fixed capacitors have also increased accordingly, which has become a major trend.

[0004] For example, a vacuum capacitor disclosed in the Chinese utility model patent with announcement number CN201918259U includes a ceramic insulating tube, an upper end cover and a lower end cover arranged at the tube openings on both sides of the insulating tube, a plurality of upper electrode rings arranged on the inner side wall of the upper end cover, and a plurality of lower electrode rings arranged on the inner side wall of the lower end cover, wherein each upper electrode ring and each lower electrode ring are arranged concentrically, and the ceramic insulating tube is fixedly connected to the upper end cover and the lower end cover by brazing. The height of this product is fixed, and the coupling height of the electrode group is fixed, that is, the capacitance is fixed, the capacitance value cannot be adjusted, and it is difficult to control the capacitance value accuracy within ±0.5%. Therefore, it is necessary to improve the prior art to overcome the defects in the prior art. Summary of the invention

[0005] The problem to be solved by the present invention is to provide a vacuum capacitor with accurately controlled capacitance, so as to overcome the defect that it is difficult to control the capacitance accuracy of the existing vacuum capacitor.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a vacuum capacitor with accurately controlled capacitance, comprising:

[0007] case;

[0008] Two electrode disks, the two electrode disks are respectively sealed and connected to two ends of the shell to form a vacuum chamber inside the shell;

[0009] and two electrode groups, the two electrode groups are fixedly connected to the two electrode disks in a one-to-one correspondence, and the two electrode groups are coupled with each other and accommodated in the vacuum chamber;

[0010] At least one of the two electrode disks is sealed and connected to the shell through a connecting piece, and the connecting piece is provided with a deformation part. When an axial force is applied to the vacuum capacitor, the connecting piece is subjected to the force so that the deformation part can be deformed to increase or decrease the length of the connecting piece in the axial direction, thereby changing the spacing between the electrode disk connected to the connecting piece and the shell to control the coupling area between the two electrode groups.

[0011] As a further improvement of the present invention, the connecting member is in the shape of a closed ring, and its two ends along the axial direction are respectively fixedly connected to the shell and the corresponding electrode disk, and the deformation portion is located in the middle of the connecting member.

[0012] As a further improvement of the present invention, the connecting member is fixedly connected to the shell and the corresponding electrode disk by welding.

[0013] As a further improvement of the present invention, the deformation portion is a folded corner with a certain angle formed by bending the connecting piece along a circle in the middle, and the tip of the folded corner is arranged toward the inside or outside of the connecting piece.

[0014] As a further improvement of the present invention, the deformation portion is formed by the connecting member being concave inward or convex outward along a circle in the middle, and its longitudinal section is arc-shaped.

[0015] As a further improvement of the present invention, the deformation portion is in the shape of a bellows.

[0016] As a further improvement of the present invention, two connecting members are provided, and the two connecting members are respectively sealed and connected between the two electrode disks and the shell.

[0017] As a further improvement of the present invention, the connecting piece is made of a metal material with a yield strength higher than 100 MPa.

[0018] As a further improvement of the present invention, the shell is tubular and made of hard insulating material.

[0019] As a further improvement of the present invention, the two electrode groups are each composed of a plurality of electrode rings arranged concentrically and spaced apart, and the electrode rings of the two electrode groups are alternately arranged and spaced apart from the inside to the outside, and the electrode rings of the two electrode groups at least partially extend into each other.

[0020] The beneficial effects of the present invention are as follows: the present invention provides a vacuum capacitor with precisely controlled capacitance, wherein a connector with a deformation portion is used between an electrode disk and a shell for sealing connection. When an axial force is applied to the vacuum capacitor, the connector is subjected to force so that the deformation portion is deformed to increase or decrease the length of the connector along the axial direction, thereby changing the spacing between the electrode disk connected to the connector and the shell, that is, changing the coupling height of the two electrode groups. By controlling the applied axial force to regulate the coupling area between the two electrode groups, precise adjustment of the capacitance is achieved, so that the capacitance accuracy of the vacuum capacitor is adjusted to within ±0.5%, thereby meeting the demand of semiconductor manufacturing equipment for the precise capacitance of the vacuum capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A cross-sectional view of a first embodiment of a vacuum capacitor capable of accurately controlling capacitance according to the present invention;

[0022] Figure 2 A cross-sectional view of a second embodiment of a vacuum capacitor capable of accurately controlling capacitance according to the present invention;

[0023] Figure 3 A cross-sectional view of a third embodiment of a vacuum capacitor capable of accurately controlling capacitance according to the present invention;

[0024] Figure 4 It is a cross-sectional view of the fourth embodiment of the vacuum capacitor capable of accurately controlling the capacitance of the present invention.

[0025] Combined with the accompanying drawings, the following description is given:

[0026] 1. Shell; 2. Electrode disk; 201. Positioning groove; 3. Electrode group; 4. Connector; 401. Deformation part; 402. Fixed end. DETAILED DESCRIPTION

[0027] A preferred embodiment of the present invention is described in detail below in conjunction with the accompanying drawings.

[0028] Embodiment 1

[0029] See also Figure 1 The present invention provides a vacuum capacitor with accurately controlled capacitance, comprising: a shell 1, two electrode disks 2 and two electrode groups 3.

[0030] The shell 1 is a tube with two open ends, and can be, but not limited to, a round tube. The shell 1 is made of a hard insulating material, such as ceramic, which has excellent insulation properties to ensure that the vacuum capacitor works safely and stably under high voltage conditions, and has high mechanical strength to help maintain the vacuum state inside the vacuum capacitor.

[0031] Further, the two electrode disks 2 may be in the shape of, but not limited to, a disk, and the two electrode disks 2 are respectively sealed and connected to both ends of the housing 1 to form a closed space inside the housing 1, and the closed space is configured as a vacuum chamber. The two electrode groups 3 are respectively fixedly connected to the opposite side surfaces of the two electrode disks 2 in a one-to-one correspondence, and the two electrode groups 3 are mutually coupled and accommodated in the vacuum chamber.

[0032] It should be noted that the two electrode groups 3 in the present invention adopt the existing conventional technology. Specifically, each electrode group 3 is composed of a plurality of electrode rings arranged concentrically and spaced apart, and the electrode rings of the upper and lower electrode groups 3 are alternately arranged and spaced apart from the inside to the outside, and the electrode rings of the two electrode groups 3 have at least a portion extending into each other, and the overlapping portion is the coupling area of ​​the two electrode groups 3. Among them, the electrode rings can be made of high-conductivity oxygen-free copper material.

[0033] In this embodiment, the vacuum capacitor capable of precisely controlling the capacitance further comprises two connecting members 4 , and the two electrode disks 2 are sealedly connected to the housing 1 through the two connecting members 4 in a one-to-one correspondence.

[0034] It should be noted that the two connecting members 4 can be formed integrally with the two electrode disks 2 respectively, or the two connecting members 4 can be processed separately. The latter is adopted in this embodiment.

[0035] As one of the important improvements of the present invention, deformation parts 401 are provided on both connecting members 4. When an axial force is applied to the vacuum capacitor, the connecting member 4 is subjected to force so that the deformation parts 401 can be deformed to increase or decrease the length of the connecting member 4 along the axial direction, thereby changing the spacing between the electrode disk 2 connected to the connecting member 4 and the shell 1, that is, changing the coupling height of the two electrode groups 3, realizing the change of the coupling area of ​​the two groups of electrodes, and realizing the precise adjustment of the capacitance by controlling the coupling area between the two electrode groups 3, so that the capacitance accuracy of the vacuum capacitor is adjusted to within ±0.5%, thereby meeting the requirements of semiconductor manufacturing equipment for the precise capacitance of the vacuum capacitor.

[0036] Further, the connector 4 is in a closed ring shape, and its shape and size are adapted to the housing 1, and in this embodiment, it is specifically in a closed circular ring shape. The two ends of the connector 4 along the axial direction are respectively fixedly connected to the end face of the housing 1 and the corresponding side face of the electrode disk 2, and the deformation part 401 is located in the middle of the connector 4. Among them, the connector 4 is fixedly connected to the housing 1 and the corresponding electrode disk 2 by welding, such as brazing.

[0037] In this embodiment, the deformation part 401 is a corner with a certain angle formed by bending the connecting member 4 along a circle in the middle, and the tip of the corner is set toward the inside of the connecting member 4. In other words, the connecting member 4 can be regarded as being processed from a circular tube with a certain length, and the corner with a certain angle, i.e., the deformation part 401, is formed by bending inward along a circle in the middle of the circular tube. When the connecting member 4 is subjected to an axial force, the two sides of the corner move away from or close to each other, and the deformation part 401 is deformed, so that the length of the connecting member 4 in the axial direction increases or decreases.

[0038] In addition, both ends of the connector 4 along the axial direction are provided with fixed ends 402, and the two fixed ends 402 are located at the upper and lower sides of the deformation part 401, and the two fixed ends 402 are both annular and coaxially distributed with the shell 1. One of the fixed ends 402 of the connector 4 is welded to the end face of the shell 1, and the two electrode disks 2 are provided with annular positioning grooves 201 on the side faces opposite to each other, and the other fixed end 402 of the connector 4 is welded in the corresponding positioning groove 201. The present invention provides the fixed end 402 on the connector 4, which can facilitate positioning and welding on the one hand, and on the other hand, when an axial force is applied to the vacuum capacitor, the welding position is not prone to the risk of fracture.

[0039] Among them, the connecting part 4 is made of a metal material with a yield strength higher than 100 MPa, such as copper, Cu-Ni alloy, Cu-Cr alloy, Cu-Sn alloy, etc., which can ensure that the deformation part 401 can be deformed when a force is applied to it, and at the same time ensure that it reaches the required mechanical strength to avoid the capacitance change caused by the force of collision and impact during installation and transportation under normal working conditions.

[0040] The capacitance control process of the vacuum capacitor capable of accurately controlling the capacitance of the present invention is as follows:

[0041] After assembly is completed, pressure is applied to the two electrode disks 2 by a press, and the capacitance of the vacuum capacitor is tested by an LCR capacitance tester. As the press continues to apply pressure, the two connectors 4 are stressed so that their respective deformation parts 401 are deformed to reduce the axial length of the connector 4, thereby shortening the distance between the two electrode disks 2 and the shell 1, and at the same time driving the two electrode groups 3 to move to change their coupling area. When the capacitance reaches within ±0.5% of the nominal capacitance, the press stops applying pressure, thereby achieving precise adjustment of the capacitance to meet the semiconductor manufacturing equipment's requirements for precise capacitance of vacuum capacitors.

[0042] Among them, the pressure provided by the press is much greater than the force of normal installation and transportation collision impact, so there is no need to worry about the capacity value of the vacuum capacitor changing during normal use by the client.

[0043] Embodiment 2

[0044] See also Figure 2 The difference between this embodiment and the first embodiment is that the deformation portion 401 is a corner with a certain angle formed by bending the connecting member 4 along a circle in the middle, and the tip of the corner is set toward the outside of the connecting member 4, that is, the tip of the corner is in a shape of convex radially outward. This structure can also achieve the technical effect obtained in the first embodiment.

[0045] Embodiment 3

[0046] See also Figure 3 The difference between this embodiment and the first embodiment is that the structure of the connecting member 4 is different.

[0047] Specifically, in this embodiment, the deformation part 401 is formed by the connection member 4 being concave inward along the middle, and its longitudinal section is an arc. When the connection member 4 is subjected to an axial force, the upper and lower ends of the deformation part 401 move toward the middle to reduce the notch, or the upper and lower ends of the deformation part 401 move away from each other to expand the notch, thereby reducing or increasing the length of the connection member 4 in the axial direction.

[0048] In addition, in this embodiment, the connecting member 4 is only provided with a fixed end 402, which is integrally connected to the upper end of the deformation part 401, and the lower end of the deformation part 401 is directly welded to the end surface of the shell 1; the two electrode disks 2 are provided with an annular positioning groove 201 on the side surfaces opposite to each other, and the fixed end 402 is welded in the corresponding positioning groove 201.

[0049] Of course, in other embodiments of the present invention, the connecting member 4 may also be provided with two fixed ends 402 as in the first embodiment.

[0050] The present invention adopts a connector 4 with an arc-shaped deformation portion 401. When an axial force is applied to the vacuum capacitor, the connector 4 is subjected to the force so that the deformation portion 401 can be deformed to increase or decrease the length of the connector 4 along the axial direction, thereby changing the spacing between the electrode disk 2 and the shell 1, that is, changing the coupling height of the two electrode groups 3, realizing a change in the coupling area of ​​the two groups of electrodes, and realizing precise adjustment of the capacitance by controlling the coupling area between the two electrode groups 3.

[0051] Embodiment 4

[0052] See also Figure 4 The difference between this embodiment and the third embodiment is that the deformation part 401 is formed by the connecting member 4 bulging outward along the middle circle, and its longitudinal section is arc-shaped, that is, the deformation part 401 is in the shape of bulging outward radially. This structure can also achieve the technical effect obtained in the third embodiment.

[0053] Embodiment 5

[0054] The difference between this embodiment and the first or second embodiment is that the shape of the deformation part 401 is different. Specifically, in this embodiment, the deformation part 401 is in the shape of a bellows, that is, the deformation part 401 is formed by connecting a plurality of the corners described in the first embodiment, or by connecting a plurality of the corners described in the second embodiment. When an axial force is applied to the vacuum capacitor, the connector 4 is subjected to the force so that the deformation part 401 is compressed or extended, thereby changing the coupling area of ​​the two electrode groups 3, and realizing the precise adjustment of the capacitance value.

[0055] Embodiment 6

[0056] The difference between this embodiment and the first embodiment is that only one connecting member 4 is configured, and the connecting member 4 is sealed between one of the electrode disks 2 and the housing 1, while the other electrode disk 2 can be sealed to the housing 1 through a connecting ring.

[0057] The connecting ring is in a conventional cylindrical shape, and can be formed integrally with the electrode disk 2 or can be formed separately.

[0058] This embodiment can also achieve the purpose of high-precision capacitance adjustment of the first embodiment by providing a connecting member 4. When an axial force is applied to the vacuum capacitor, the connecting member 4 is subjected to the force so that the deformation portion 401 can be deformed to increase or decrease the length of the connecting member 4 in the axial direction, thereby changing the spacing between an electrode disk 2 connected to the connecting member 4 and the housing 1, thereby changing the coupling area of ​​the two electrode groups 3, and realizing accurate capacitance adjustment.

[0059] Many specific details are described in the above description to facilitate a full understanding of the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person familiar with the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A vacuum capacitor capable of precisely controlling capacitance, comprising: Housing (1); Two electrode disks (2), the two electrode disks (2) being respectively sealed and connected to two ends of the shell (1) to form a vacuum chamber inside the shell (1); and two electrode groups (3), the two electrode groups (3) being fixedly connected to the two electrode disks (2) in a one-to-one correspondence, and the two electrode groups (3) being coupled to each other and accommodated in the vacuum chamber; The invention is characterized in that at least one of the two electrode disks (2) is sealedly connected to the shell (1) through a connecting piece (4), and the connecting piece (4) is provided with a deformation portion (401). When an axial force is applied to the vacuum capacitor, the connecting piece (4) is subjected to the force so that the deformation portion (401) can be deformed to increase or decrease the axial length of the connecting piece (4), thereby changing the distance between the electrode disk (2) connected to the connecting piece (4) and the shell (1), so as to control the coupling area between the two electrode groups (3).

2. The vacuum capacitor with accurately controlled capacitance according to claim 1, characterized in that: The connecting member (4) is in the shape of a closed ring, and its two ends along the axial direction are respectively fixedly connected to the housing (1) and the corresponding electrode disk (2), and the deformation portion (401) is located in the middle of the connecting member (4).

3. The vacuum capacitor with accurately controllable capacitance according to claim 2, characterized in that: The connecting member (4) is fixedly connected to the housing (1) and the corresponding electrode disk (2) by welding.

4. The vacuum capacitor with accurately controllable capacitance according to claim 2, characterized in that: The deformation portion (401) is a folded corner with a certain angle formed by bending the connecting member (4) along a circle in the middle, and the tip of the folded corner is arranged toward the inside or outside of the connecting member (4).

5. The vacuum capacitor with accurately controlled capacitance according to claim 2, characterized in that: The deformation part (401) is formed by the connection member (4) being concave inward or convex outward along a circle in the middle, and its longitudinal section is arc-shaped.

6. The vacuum capacitor capable of accurately controlling capacitance according to claim 2, characterized in that: The deformation portion (401) is in the shape of a bellows.

7. The vacuum capacitor capable of accurately controlling capacitance according to claim 1, characterized in that: Two connecting members (4) are provided, and the two connecting members (4) are respectively sealed and connected between the two electrode disks (2) and the housing (1).

8. The vacuum capacitor capable of accurately controlling capacitance according to claim 1, characterized in that: The connecting piece (4) is made of a metal material with a yield strength higher than 100 MPa.

9. The vacuum capacitor capable of accurately controlling capacitance according to claim 1, characterized in that: The shell (1) is tubular and is made of hard insulating material.

10. The vacuum capacitor capable of accurately controlling capacitance according to claim 1, characterized in that: The two electrode groups (3) are each composed of a plurality of electrode rings arranged concentrically and at intervals, and the electrode rings of the two electrode groups (3) are alternately arranged and spaced from the inside to the outside, and the electrode rings of the two electrode groups (3) at least partially extend into each other.

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