Circuit board and method of manufacturing the same

Abstract

The application provides a circuit board and a manufacturing method thereof. The circuit board has a first area, a connecting area and a second area which are connected with each other, the first area and the second area are oppositely arranged, the circuit board comprises a capacitor layer and a coil layer, the capacitor layer comprises a first capacitor sheet located in the first area and a second capacitor sheet located in the second area, the coil layer comprises a first coil located in the first area and a second coil located in the second area, a first end of the first coil is electrically connected with a third end of the second coil through a conductive line, a second end of the first coil and a fourth end of the second coil extend to the connecting area and form two output ends, the first coil is used for generating a first magnetic force, the second coil is used for generating a second magnetic force which is opposite to the first magnetic force, and the distance between the first area and the second area is variable, so that the capacitance between the first capacitor sheet and the second capacitor sheet is changed. The circuit board provided by the application is internally provided with a trimmer capacitor structure, the trimmer capacitor structure occupies a small space, has a simple structure and low cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit board, in particular to a circuit board and a manufacturing method thereof. BACKGROUND

[0002] The characteristic of the capacitor is mainly to pass alternating current while blocking direct current, and it is commonly used for inter-electrode coupling, filtering, decoupling, bypassing and signal tuning. The adjustable capacitor, also known as micro-adjustable capacitor (or micro-variable capacitor, variable capacitor, etc.), is a kind of capacitor whose capacitance can be continuously adjusted within a certain range. The micro-adjustable capacitor is widely used as a tuning and compensation capacitor / correction capacitor in various tuning and oscillation circuits of radio devices (such as radio, television) or NFC / RFID card reader and other devices.

[0003] However, the existing micro-adjustable capacitor has the problems of large space occupation, welding requirement, predetermined position reservation in the PCB, high cost, etc. SUMMARY

[0004] In view of this, in order to solve at least one of the above problems, it is necessary to provide a circuit board containing a micro-adjustable capacitor.

[0005] In addition, it is also necessary to provide a manufacturing method of the above-mentioned circuit board.

[0006] The circuit board provided by the embodiment of the present application has the first area, the connecting area and the second area connected with each other, the first area and the second area are located at two ends of the connecting area and are oppositely arranged, the circuit board comprises a capacitor layer and a coil layer stacked with the capacitor layer, the capacitor layer comprises a first capacitor sheet located in the first area and a second capacitor sheet located in the second area, the first capacitor sheet has a first conductive part extending to the connecting area and used for electrical lead-out, and the second capacitor sheet has a second conductive part extending to the connecting area and used for electrical lead-out; the coil layer comprises a first coil located in the first area and a second coil located in the second area, the first coil comprises a first end and a second end, the second coil comprises a third end and a fourth end, the first end is electrically connected with the third end through a conductive line, and the second end and the fourth end extend to the connecting area and form two output ends, wherein the first coil is used for generating a first magnetic force, the second coil is used for generating a second magnetic force, the directions of the first magnetic force and the second magnetic force are opposite, and the distance between the first area and the second area is variable to change the capacitance between the first capacitor sheet and the second capacitor sheet.

[0007] In some possible embodiments, the first region has a first bending line at the connection with the connection region, the second region has a second bending line at the connection with the connection region, the first region can be bent towards or away from the connection region around the first bending line, and the second region can be bent towards or away from the connection region around the second bending line.

[0008] In some possible embodiments, the first region, the connection region and the second region form a U-shaped pattern, and the capacitor layer is located at the innermost layer of the U-shaped pattern.

[0009] In some possible embodiments, a surface of the first bending line is provided with a first elastic piece, and a surface of the second bending line is provided with a second elastic piece.

[0010] In some possible embodiments, the circuit board further comprises a conductive layer between the capacitor layer and the coil layer, and the conductive circuit is located on the conductive layer.

[0011] In some possible embodiments, the conductive circuit comprises a third coil located in the first region, a fourth coil located in the second region, and a connection part located in the connection region, two ends of the connection part are connected to one end of the third coil and one end of the fourth coil respectively, one end of the third coil away from the connection part is electrically connected to the first end, one end of the fourth coil away from the connection part is electrically connected to the third end, and the third coil and the fourth coil have the same current direction.

[0012] In some possible embodiments, the conductive circuit is located on the capacitor layer and is electrically isolated from the first capacitor piece and the second capacitor piece.

[0013] Embodiments of the present application also provide a manufacturing method of a circuit board, the manufacturing method comprising:

[0014] providing a circuit substrate, the circuit substrate having a first region, a connection region and a second region connected to each other, the first region and the second region being located at two ends of the connection region and arranged oppositely, the circuit substrate comprising a substrate layer, and a first metal layer and a second metal layer arranged on two opposite surfaces of the substrate layer;

[0015] patterning the first metal layer to form a capacitor layer, the capacitor layer comprising a first capacitor piece located in the first region and a second capacitor piece located in the second region, the first capacitor piece having a first conductive part extending to the connection region and used for electrical lead-out, and the second capacitor piece having a second conductive part extending to the connection region and used for electrical lead-out; and

[0016] patterning the second metal layer to form a coil layer, the coil layer comprising a first coil in the first region and a second coil in the second region, the first coil comprising a first end and a second end, the second coil comprising a third end and a fourth end, the first end electrically connected to the third end through a conductive line, the second end and the fourth end extending to the connection region and forming two output ends, wherein the current directions in the first coil and the second coil are opposite, to obtain the circuit board.

[0017] In some possible embodiments, the method for manufacturing the circuit substrate comprises:

[0018] providing a first substrate, the first substrate having the first region, the connection region and the second region, the first substrate comprising a first base layer, the first metal layer on a surface of the first base layer, and a third metal layer on a surface of the first base layer away from the first metal layer;

[0019] patterning the third metal layer to form a conductive layer, the conductive line being in the conductive layer, the conductive line comprising a third coil in the first region, a fourth coil in the second region, and a connection part in the connection region, two ends of the connection part being connected to one end of the third coil and one end of the fourth coil respectively, one end of the third coil and one end of the fourth coil away from the connection part being electrically connected to the first metal layer, the current directions of the third coil and the fourth coil being the same; and

[0020] forming a first insulating layer on a surface of the conductive layer, and forming a second base layer and the second metal layer on a surface of the first insulating layer, the second metal layer being on a surface of the second base layer away from the first insulating layer.

[0021] In some possible embodiments, in the step of patterning the first metal layer to form the capacitor layer, the method further comprises:

[0022] patterning the first metal layer to form the conductive line, the conductive line being electrically isolated from the first capacitor plate and the second capacitor plate.

[0023] In some possible embodiments, after the step of patterning the second metal layer to form the coil layer, the method further comprises:

[0024] forming a first bending line at the connection between the first region and the connection region, and forming a second bending line at the connection between the second region and the connection region, the first region being bendable towards or away from the connection region around the first bending line, and the second region being bendable towards or away from the connection region around the second bending line.

[0025] In some possible embodiments, after forming the first bend line and the second bend line, the manufacturing method further includes:

[0026] A first spring sheet is provided on the surface of the first bend line, and a second spring sheet is provided on the surface of the second bend line.

[0027] Compared to existing technologies, this application's embodiments design a capacitor layer and a coil layer in the circuit board. By changing the relative distance between the first coil and the second coil, the capacitance value between the first capacitor sheet and the second capacitor sheet can be changed, thereby forming a fine-tuning capacitor structure within the circuit board. The fine-tuning capacitor structure is small in size and is directly formed within the circuit board without soldering steps, resulting in a simple overall circuit board structure and lower cost. Moreover, the circuit board with the fine-tuning capacitor structure can be used as an independent capacitor circuit board or as part of a circuit board, offering flexible structural design and strong adaptability. In addition, by setting the first and second springs, the rigidity of the deflection area can be enhanced while ensuring the flexibility of the deflection area where the first and second bend lines are located, reducing the risk of deflection area breakage and improving the reliability of the circuit board. Furthermore, after bending, rigid shaping can be achieved, ensuring that the relative distance between the first and second areas is fixed after shaping, thereby improving the stability of the capacitance value. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the circuit board in a flattened state according to an embodiment of this application.

[0029] Figure 2 for Figure 1 A schematic diagram of the circuit board in a bent state.

[0030] Figure 3 For along Figure 1 Sectional view of section III-III.

[0031] Figure 4 for Figure 1 A schematic diagram of the structure of the circuit board in the state of separation of each layer.

[0032] Figure 5 This is a schematic diagram of the structure of a circuit board in a separated state according to another embodiment of this application.

[0033] Figure 6 This is a schematic diagram of the structure of a circuit board in a separated state according to another embodiment of this application.

[0034] Figure 7 This is a schematic diagram of the operation of the fine-tuning capacitor structure in the circuit board in one embodiment of this application.

[0035] Figure 8 for Figure 7 A schematic diagram of the first and second zones in the flat state.

[0036] Figure 9 Fig. 1 is a schematic diagram of a first zone and a second zone in a deformed state. Figure 7

[0037] Figure 10 Fig. 4 is a flow chart of a manufacturing process of a circuit board according to an embodiment of the present application.

[0038] Figures 11 to 16 Fig. 5 is a structural schematic diagram of a manufacturing process of a circuit board according to an embodiment of the present application.

[0039] Main component symbol explanation

[0040]

[0041]

[0042] The following detailed description will further describe the present application with reference to the above mentioned drawings. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application.

[0044] It should be noted that when an element is referred to as being "fixed" to another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element. When an element is referred to as being "disposed on" another element, it can be directly on the other element or there can be an intervening element.

[0045] Reference should be made to Figures 1 to 3 ​The embodiment of the present application provides a circuit board 100, which has a first area A, a connecting area C and a second area B connected with each other, the first area A and the second area B are located at two ends of the connecting area C and are oppositely arranged. The circuit board 100 comprises a capacitor layer 1 and a coil layer 2 which is stacked with the capacitor layer 1. The capacitor layer 1 comprises a first capacitor sheet 11 located in the first area A and a second capacitor sheet 12 located in the second area B, the first capacitor sheet 11 has a first conductive part 13 extending to the connecting area C and used for electrical lead-out, and the second capacitor sheet 12 has a second conductive part 14 extending to the connecting area C and used for electrical lead-out. The coil layer 2 comprises a first coil 21 located in the first area A and a second coil 22 located in the second area B, the first coil 21 comprises a first end 23 and a second end 24, the second coil 22 comprises a third end 25 and a fourth end 26, the first end 23 is electrically connected with the third end 25 through a conductive line 31, and the second end 24 and the fourth end 26 extend to the connecting area C and form two output ends, specifically, the two output ends can be used for connecting the positive electrode and the negative electrode of an external power supply. Wherein, the first coil 21 is used for generating a first magnetic force, the second coil 22 is used for generating a second magnetic force, the direction of the first magnetic force is opposite to that of the second magnetic force, so that the distance between the first area A and the second area B is variable, so as to change the capacitance between the first capacitor sheet 11 and the second capacitor sheet 12. Specifically, the winding directions of the first coil 21 and the second coil 22 can be set as opposite, so that the current directions in the first coil 21 and the second coil 22 are opposite, so that the direction of the first magnetic force generated by the first coil 21 is opposite to that of the second magnetic force generated by the second coil 22, under the action of the first magnetic force and the second magnetic force with opposite directions, the first area A and the second area B can be bent in a direction of moving away from each other, so that the distance between the first area A and the second area B is increased, or the first area A and the second area B can be bent in a direction of moving close to each other, so that the distance between the first area A and the second area B is decreased.

[0046] In some embodiments, the first area A has a first bending line 4 at the connection with the connecting area C, the second area B has a second bending line 5 at the connection with the connecting area C, and the first area A can be bent around the first bending line 4 towards or away from the second area B, and the second area B can be bent around the second bending line 5 towards or away from the first area A.

[0047] In some embodiments, the first area A, the connecting area C and the second area B form a U-shaped type, and the capacitor layer 1 is located in the innermost layer of the U-shaped type. By arranging the capacitor layer 1 in the innermost layer (the surface of the first area A and the second area B moving close to each other is an inner surface), the influence on the capacitance can be reduced, and the change of the capacitance value is more accurate.

[0048] In some embodiments, the surface of the first bending line 4 is provided with a first elastic sheet 6, and the surface of the second bending line 5 is provided with a second elastic sheet 7. By providing the first elastic sheet 6 and the second elastic sheet 7 in the bending area, the rigidity of the bending area can be enhanced, the risk of breaking of the bending area can be reduced, and the reliability of the circuit board 100 can be improved, on the premise that the bending area where the first bending line 4 and the second bending line are located has the bending property. Specifically, the first elastic sheet 6 and the second elastic sheet 7 can both be copper sheets, which can be rigidly shaped after being bent, so as to ensure that the relative distance between the first area A and the second area B is fixed after shaping, thereby improving the stability of the capacitance value.

[0049] In some embodiments, as shown in Figure 4 The circuit board 100 further includes a conductive layer 3 between the capacitor layer 1 and the coil layer 2, and the conductive circuit 31 is located on the conductive layer 3. Specifically, the conductive circuit 31 includes a third coil 32 located in the first area A, a fourth coil 33 located in the second area B, and a connecting portion 34 located in the connecting area C, two ends of the connecting portion 34 are respectively connected to one end of the third coil 32 and one end of the fourth coil 33, one end of the third coil 32 away from the connecting portion 34 is electrically connected to the first end 23, and one end of the fourth coil 33 away from the connecting portion 34 is electrically connected to the third end 25. The current directions of the third coil 32 and the fourth coil 33 are the same, specifically, the winding directions of the third coil 32 and the fourth coil 33 can be set to be the same, so that the current directions in the third coil 32 and the fourth coil 33 are the same.

[0050] In some embodiments, the capacitor layer 1 and the coil layer 2 are further provided with a first base layer 81, an insulating layer 82, and a second base layer 83. The coil layer 2 is located on one surface of the first base layer 81, the conductive layer 3 is located on the surface of the first base layer 81 away from the coil layer 2, the insulating layer 82 is located on the surface of the conductive layer 3 and extends to the circuit gap of the conductive layer 3, the second base layer 83 is located on the surface of the insulating layer 82, and the capacitor layer 1 is located on the surface of the second base layer 83 away from the insulating layer 82.

[0051] In other embodiments, as shown in Figure 5 The circuit board 100 further includes a conductive layer 3 between the capacitor layer 1 and the coil layer 2, and the conductive circuit 31 is located on the conductive layer 3. Specifically, the conductive circuit 31 can be a wire with two connecting ends, which is used to electrically connect the first end 23 of the first coil 21 and the third end 25 of the second coil 22. By increasing the conductive layer 3, the electrical conduction of the first coil 21 and the second coil 22 can be facilitated.

[0052] In other embodiments, as shown in Figure 6As shown, the conductive circuit 31 is located on the capacitor layer 1 and is electrically isolated from the first capacitor plate 11 and the second capacitor plate 12. That is, the conductive circuit 31 is made on the same layer as the capacitor layer 1, so that the circuit board 100 has a two-layer structure, which is advantageous for making full use of the space in the circuit board 100 and reducing the thickness of the circuit board 100. In this embodiment, the insulating layer 82 and the second base layer 83 are not needed, and the capacitor layer 1 and the coil layer 2 are separated by the first base layer 81 to form a two-layer structure. The through hole is formed through the first base layer 81 to realize the electrical conduction between the conductive circuit 31 and the first coil 21 and the second coil 22.

[0053] It can be understood that other circuit layers (not shown in the figure) can also be formed in the circuit board 100, and the capacitor layer 1 and the coil layer 2 are directly electrically connected to the other circuit layers to form an integrated circuit board with multiple functions. It can be understood that the circuit board 100 can also be a capacitor circuit board, and the first conductive part 13 and the second conductive part 14 can be used to form external solder pads for directly soldering external connectors or other circuit boards.

[0054] As shown in Figures 7 to 9 , the first bending line 4 can form a bending area at the connection between the first area A and the connection area C, and the second bending line 5 can also form a bending area at the connection between the second area B and the connection area C, so that the first area A and the second area B can be bent relative to the connection area C, thereby changing the relative distance between the first area A and the second area B. Specifically, the bending of the first area A and the second area B relative to the connection area C is realized by the first coil 21 and the second coil 22. In the flat state, as shown in Figure 8 , the first area A and the second area B are arranged substantially perpendicular to the connection area C, and at this time the distance between the first area A and the second area B is denoted as h1, and the capacitance between the first capacitor plate 11 and the second capacitor plate 12 is denoted as C1. Since the first coil 21 and the second coil 22 are wound in opposite directions, when electrified, the first magnetic force generated by the first coil 21 and the second magnetic force generated by the second coil 22 are in opposite directions, as shown in Figure 9 , under the action of the first magnetic force and the second magnetic force, the first area A and the second area B can be bent in a direction away from each other, so that the distance between the first area A and the second area B increases, forming a deformed state, thereby changing the distance between the first capacitor plate 11 and the second capacitor plate 12, increasing the distance from h1 to h2, and further changing the capacitance value between the first capacitor plate 11 and the second capacitor plate 12, changing the capacitance value C1 to C2. When the current value decreases to 0, under the action of the first elastic sheet 6 and the second elastic sheet 7, the first area A and the second area B will return to the flat state as shown in Figure 8 . Therefore, by controlling the size of the current in the first coil 21 and the second coil 22, the distance between the first area A and the second area B can be controlled, and the size of the capacitance value can be adjusted, forming a fine-tuning capacitor structure.

[0055] Referring to Figure 10 The embodiment of the present application also provides a manufacturing method of the circuit board 100, which comprises the following steps:

[0056] Step S1, as shown in Figures 11 to 14 , a circuit substrate 10 is provided, which has a first area A, a connecting area C and a second area B connected with each other, the first area A and the second area B are located at two ends of the connecting area C and are oppositely arranged, the circuit substrate 10 comprises a substrate layer 20, and a first metal layer 30 and a second metal layer 40 arranged on opposite surfaces of the substrate layer 20.

[0057] Step S2, as shown in Figure 15 , and referring to Figure 4 , the first metal layer 30 is patterned to form a capacitor layer 1, the capacitor layer 1 comprises a first capacitor sheet 11 located in the first area A and a second capacitor sheet 12 located in the second area B, the first capacitor sheet 11 has a first conductive part 13 extending to the connecting area C and used for electrical lead-out, and the second capacitor sheet 12 has a second conductive part 14 extending to the connecting area C and used for electrical lead-out.

[0058] Step S3, as shown in Figure 15 , and referring to Figure 4 , the second metal layer 40 is patterned to form a coil layer 2, the coil layer 2 comprises a first coil 21 located in the first area A and a second coil 22 located in the second area B, the first coil 21 comprises a first end 23 and a second end 24, the second coil 22 comprises a third end 25 and a fourth end 26, the first end 23 is electrically connected with the third end 25 through a conductive line 31, and the second end 24 and the fourth end 26 extend to the connecting area C and form two output ends, wherein the current directions in the first coil 21 and the second coil 22 are opposite, and the circuit board 100 is obtained.

[0059] In some embodiments, in step S1, the manufacturing method of the circuit substrate 10 comprises:

[0060] Step S11, as shown in Figure 11 , a first substrate 50 is provided, which has the first area A, the connecting area C and the second area B, and the first substrate 50 comprises a first substrate layer 81, the first metal layer 30 located on a surface of the first substrate layer 81, and a third metal layer 60 located on a surface of the first substrate layer 81 away from the first metal layer 30.

[0061] Step S12, as shown in Figure 12 and Figure 13 , and referring toFigure 4 The third metal layer 60 is patterned to form a conductive layer 3. A conductive line 31 is located in the conductive layer 3. The conductive line 31 includes a third coil 32 located in the first region A, a fourth coil 33 located in the second region B, and a connecting portion 34 located in the connecting region C. The two ends of the connecting portion 34 are respectively connected to one end of the third coil 32 and one end of the fourth coil 33. The ends of the third coil 32 and the fourth coil 33 away from the connecting portion C are both electrically connected to the first metal layer 30. The current directions of the third coil 32 and the fourth coil 33 are the same, that is, the winding directions of the third coil 32 and the fourth coil 33 are the same. It is understood that in other embodiments, references are made in conjunction with... Figure 5 The conductive line 31 in the conductive layer 3 can also be a metal wire with both ends connected to the first metal layer 30.

[0062] Step S13, as follows Figure 14 As shown, an insulating layer 82 is formed on the surface of the conductive layer 3, and a second base layer 83 and a second metal layer 40 are formed on the surface of the insulating layer 82, with the second metal layer 40 located on the surface of the second base layer 83 opposite to the insulating layer 82. Specifically, the second base layer 83 and the second metal layer 40 can be formed on the surface of the insulating layer 82 by lamination.

[0063] In other embodiments, in step S2, reference is made in conjunction with... Figure 6 While patterning the first metal layer 30 to form the capacitor layer 1, the method also includes the following steps:

[0064] The first metal layer 30 is patterned to form the conductive line 31, which is electrically isolated from the first capacitor sheet 11 and the second capacitor sheet 12, and both ends of the conductive line 31 are electrically connected to the second metal layer 50. The conductive line 31 can be fabricated simultaneously with the capacitor layer 1, placing both on the same layer, simplifying the fabrication process and reducing costs.

[0065] In some embodiments, such as Figure 16 The method further includes the following steps after step S3:

[0066] A first bend line 4 is formed at the connection between the first region A and the connecting region C, and a second bend line 5 is formed at the connection between the second region B and the connecting region C. The first region A can bend around the first bend line 4 toward or away from the second region B, and the second region B can bend around the second bend line 5 toward or away from the first region A.

[0067] Specifically, the first bending line 4 and the second bending line 5 are both formed by forming at least one row of through holes arranged in a straight line, which can be formed by laser drilling or mechanical drilling. The diameter of the through hole needs to be controlled within a small range, which can ensure the bending property while not reducing the strength and reliability of the circuit board 100. In addition, the hole should not be drilled on the line when drilling.

[0068] Specifically, before forming the first bending line 4 and the second bending line 5, a CVL protective layer 9 can also be attached to the surface of the capacitor layer 1 and the coil layer 2 respectively. The through holes of the first bending line 4 and the second bending line 5 penetrate the protective layer 9. Then, the first spring 6 and the second spring 7 are attached to the surface of the protective layer 9. Specifically, the first spring 6 and the second spring 7 are combined on the surface of the protective layer 9 close to the coil layer 2 to reduce the impact on the capacitor layer 1.

[0069] In some embodiments, as shown in Figure 3 After forming the first bending line 4 and the second bending line 5, the manufacturing method further includes the steps of:

[0070] A first spring 6 is arranged on the surface of the first bending line 4, and a second spring 7 is arranged on the surface of the second bending line 5.

[0071] It can be understood that the preparation method of the capacitor layer 1, the coil layer 2 and the conductive layer 3 can be prepared by additive method, and also can be prepared by subtractive method.

[0072] The embodiments of the present application design the capacitor layer 1 and the coil layer 2 in the circuit board 100. By changing the relative distance between the first coil 21 and the second coil 22, the capacitance value between the first capacitor sheet 11 and the second capacitor sheet 12 can be changed, thereby forming a fine tuning capacitor structure in the circuit board 100. The fine tuning capacitor structure has small size and is directly formed in the circuit board 100 without the need for welding steps. The overall circuit board 100 has simple structure and low cost. Moreover, the circuit board 100 with the fine tuning capacitor structure can be used as an independent capacitor circuit board or as a part of a circuit board. The structure design is flexible and has strong adaptability. In addition, by arranging the first spring 6 and the second spring 7, the rigidity of the bending area where the first bending line 4 and the second bending line 5 are located can be enhanced, the risk of breaking the bending area can be reduced, the reliability of the circuit board 100 can be improved, and the rigidity of the bending area can be fixed after bending, so as to fix the relative distance between the first area A and the second area B and improve the stability of the capacitance value.

[0073] The above description is only a specific implementation of an optimized embodiment of the present application, but in actual application process, it cannot be limited to this embodiment.

Claims

1. A circuit board, characterized by, The circuit board has a first area, a connecting area and a second area connected with each other, the first area and the second area are oppositely arranged at two ends of the connecting area, and the circuit board comprises: a capacitor layer comprising a first capacitor sheet in the first area and a second capacitor sheet in the second area, the first capacitor sheet has a first conductive part extending to the connecting area and used for electrical lead-out, and the second capacitor sheet has a second conductive part extending to the connecting area and used for electrical lead-out; and a coil layer stacked with the capacitor layer, the coil layer comprises a first coil in the first area and a second coil in the second area, the first coil comprises a first end and a second end, the second coil comprises a third end and a fourth end, the first end is electrically connected with the third end through a conductive circuit, and the second end and the fourth end extend to the connecting area and form two output ends, wherein the first area has a first bending line at the connection with the connecting area, the second area has a second bending line at the connection with the connecting area, the first area can be bent towards or away from the connecting area around the first bending line, the second area can be bent towards or away from the connecting area around the second bending line, the first coil is used for generating a first magnetic force, the second coil is used for generating a second magnetic force, the directions of the first magnetic force and the second magnetic force are opposite, and the distance between the first area and the second area is variable to change the capacitance between the first capacitor sheet and the second capacitor sheet.

2. The circuit board of claim 1, wherein, The first area, the connecting area and the second area form a U-shaped type, and the capacitor layer is located in the innermost layer of the U-shaped type.

3. The circuit board of claim 2, wherein, The surface of the first bending line is provided with a first elastic sheet, and the surface of the second bending line is provided with a second elastic sheet.

4. The circuit board of claim 1, wherein, The circuit board further comprises a conductive layer between the capacitor layer and the coil layer, and the conductive circuit is located in the conductive layer.

5. The circuit board of claim 4, wherein, The conductive circuit comprises a third coil in the first area, a fourth coil in the second area and a connecting part in the connecting area, two ends of the connecting part are connected with one end of the third coil and one end of the fourth coil respectively, one end of the third coil away from the connecting part is electrically connected with the first end, one end of the fourth coil away from the connecting part is electrically connected with the third end, and the current directions of the third coil and the fourth coil are the same.

6. The circuit board of claim 1, wherein, The conductive circuit is located in the capacitor layer and is electrically isolated from the first capacitor sheet and the second capacitor sheet.

7. A method of manufacturing a circuit board, characterized by, comprises: a circuit board is provided, the circuit board has a first area, a connecting area and a second area connected with each other, the first area and the second area are oppositely arranged at two ends of the connecting area, and the circuit board comprises a substrate layer, and a first metal layer and a second metal layer arranged on opposite surfaces of the substrate layer; patterning the first metal layer to form a capacitor layer, the capacitor layer comprising a first capacitor plate in the first region and a second capacitor plate in the second region, the first capacitor plate having a first conductive part extending to the connection region and used for electrical lead-out, the second capacitor plate having a second conductive part extending to the connection region and used for electrical lead-out; patterning the second metal layer to form a coil layer, the coil layer comprising a first coil in the first region and a second coil in the second region, the first coil comprising a first end and a second end, the second coil comprising a third end and a fourth end, the first end being electrically connected to the third end through a conductive line, the second end and the fourth end extending to the connection region and forming two output ends, wherein the current directions in the first coil and the second coil are opposite; and forming a first bending line at the connection between the first region and the connection region, and forming a second bending line at the connection between the second region and the connection region, the first region being bendable towards or away from the connection region around the first bending line, and the second region being bendable towards or away from the connection region around the second bending line, to obtain the circuit board.

8. The method of manufacturing a circuit board according to Claim 7, wherein The manufacturing method of the circuit substrate comprises: providing a first substrate having the first region, the connection region and the second region, the first substrate comprising a first base layer, the first metal layer on a surface of the first base layer, and a third metal layer on a surface of the first base layer opposite to the first metal layer; patterning the third metal layer to form a conductive layer, the conductive line being in the conductive layer, the conductive line comprising a third coil in the first region, a fourth coil in the second region, and a connection part in the connection region, two ends of the connection part being connected to one end of the third coil and one end of the fourth coil respectively, one end of the third coil and one end of the fourth coil away from the connection part being electrically connected to the first metal layer, and the current directions of the third coil and the fourth coil being the same; and forming a first insulating layer on a surface of the conductive layer, and forming a second base layer and the second metal layer on a surface of the first insulating layer, the second metal layer being on a surface of the second base layer opposite to the first insulating layer.

9. The method of manufacturing a circuit board according to Claim 7, wherein In the step of patterning the first metal layer to form the capacitor layer, the manufacturing method further comprises: patterning the first metal layer to form the conductive line, the conductive line being electrically isolated from the first capacitor plate and the second capacitor plate.

10. The method of manufacturing a circuit board according to Claim 7, wherein After forming the first bending line and the second bending line, the manufacturing method further comprises: providing a first elastic sheet on a surface of the first bending line, and providing a second elastic sheet on a surface of the second bending line.

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