Board-to-board connection structure and preparation method thereof

Abstract

A board-to-board connection structure and a preparation method thereof, the board-to-board connection structure includes a first circuit board, a second circuit board and a connector, the connector includes a housing, a first electrical connection portion located outside the housing, and a second electrical connection portion located in the housing and electrically connected to the first electrical connection portion; the first circuit board includes a first outer circuit layer and a first conductive layer; the second circuit board includes a second outer circuit layer; the connector is connected to the first conductive layer via the first electrical connection portion, the second circuit board is disposed in the housing, and the second electrical connection portion is electrically connected to the second outer circuit layer. The board-to-board connection structure provided by the present invention uses a connector to electrically connect the two circuit boards at the sides, thereby ensuring that the thickness of the circuit boards does not increase after connection, which is conducive to the thinning of electronic products. In addition, the present invention also provides a preparation method for a board-to-board connection structure.

Description

Technical Field

[0001] The present invention relates to a printed circuit board technology, and in particular to a board-to-board connection structure and a preparation method thereof. Background Art

[0002] With the widespread application of printed circuit boards in the electronic field, in order to give full play to the multi-functions of electronic products, it is usually necessary to integrate two or more circuit boards with different functions together.

[0003] Traditional connection methods include connection through anisotropic conductive adhesive (ACF), pulse hot bar welding (hotbar), board-to-board connector (BTB), etc.

[0004] However, the above connection method will increase the total thickness of the circuit board due to the existence of the inter-board connection layer, which cannot meet the development trend of thinner and more flexible electronic products. Summary of the invention

[0005] In view of the above, it is necessary to propose a board-to-board connection structure that realizes connection between different circuit boards without increasing the thickness of the connection product.

[0006] In addition, the present invention also provides a method for preparing the above-mentioned board-to-board connection structure.

[0007] The present invention provides a board-to-board connection structure, comprising a first circuit board, a second circuit board and a connector electrically connecting the first circuit board and the second circuit board.

[0008] The connector includes a housing, a first electrical connection portion located outside the housing, and a second electrical connection portion located in the housing and electrically connected to the first electrical connection portion.

[0009] The first circuit board includes a first base layer and a first outer circuit layer located on the first base layer.

[0010] The second circuit board includes a second base layer and a second outer circuit layer located on the second base layer. A second conductive layer electrically connected to the second outer circuit layer is disposed on a side surface of the second circuit board.

[0011] The connector is connected to the first conductive layer via the first electrical connection portion, the second circuit board is disposed in the housing, and the second electrical connection portion is electrically connected to the second outer circuit layer.

[0012] In an embodiment of the present application, the first outer circuit layer includes a first connection pad, the first conductive layer is connected to the first connection pad, and the first electrical connection portion is electrically connected to the first connection pad and the first conductive layer.

[0013] In the embodiment of the present application, a second conductive layer electrically connected to the second outer circuit layer is provided on the side surface of the second circuit board.

[0014] In an embodiment of the present application, the second electrical connection portion includes at least one contact and at least one clamping device, the contact is electrically connected to the second conductive layer, and the clamping device includes two elastic sheets arranged opposite to each other, and the two elastic sheets are used to clamp the second circuit board.

[0015] In the embodiment of the present application, the second outer circuit layer includes a second connection pad, and the spring sheet elastically abuts against the second connection pad.

[0016] In the implementation manner of the present application, the first electrical connection portion is fixed to the first conductive layer by means of a conductive adhesive or a conductive paste.

[0017] In the implementation manner of the present application, fixing glue is filled between the shell and the second conductive layer.

[0018] The present invention also provides a method for preparing a board-to-board connection structure, comprising the following steps:

[0019] A first circuit board is provided, comprising a first base layer, a first outer circuit layer arranged on at least one surface of the first base layer, and a first conductive layer arranged on one side end surface of the first circuit board, wherein the first conductive layer is electrically connected to the first outer circuit layer.

[0020] A connector is provided. The connector includes a housing, a first electrical connection portion located outside the housing, and a second electrical connection portion located in the housing and electrically connected to the first electrical connection portion.

[0021] The first electrical connection portion is fixedly and electrically connected to the first conductive layer at a side surface of the first circuit board.

[0022] A second circuit board is provided. The second circuit board includes a second base layer and a second outer circuit layer disposed on at least one surface of the second base layer.

[0023] One end of the second circuit board is placed in the housing, and the second outer circuit layer is electrically connected to the second electrical connection portion to obtain the board-to-board connection structure.

[0024] In an embodiment of the present application, the first outer circuit layer includes a first connection pad, the first conductive layer is connected to the first connection pad, and the first electrical connection portion is electrically connected to the first connection pad and the first conductive layer.

[0025] In the embodiment of the present application, a second conductive layer is provided on an end surface of the second circuit board close to a side of the first circuit board, and the second conductive layer is electrically connected to the second outer circuit layer.

[0026] In an embodiment of the present application, the second electrical connection portion includes at least one contact and at least one clamping device, the contact is electrically connected to the second conductive layer, and the clamping device includes two elastic sheets arranged opposite to each other, and the two elastic sheets are used to clamp the second circuit board.

[0027] In the embodiment of the present application, the second outer circuit layer includes a second connection pad, and the spring sheet elastically abuts against the second connection pad.

[0028] In the implementation manner of the present application, after the end of the second circuit board provided with the second conductive layer is placed in the housing, a fixing glue is filled between the housing and the second circuit board.

[0029] The board-to-board connection structure provided by the present invention has the following advantages:

[0030] 1. The connector is used to connect the first circuit board and the second circuit board at the side and realize electrical connection at the same time, which ensures that the thickness of the circuit boards will not increase after connection, is conducive to reducing the thickness of the board-to-board connection structure, and is conducive to the development of electronic products towards lighter and thinner.

[0031] 2. The connector has a simple structure and can be electrically connected to the first circuit board through conductive glue or conductive paste. The second circuit board only needs to be inserted into the housing through the opening to be fixedly connected through the clamping device.

[0032] 3. The design of the clamping device and the contact can realize multi-sided electrical connection according to the wiring structure design of the actual circuit board, which can effectively increase the connection area between the second circuit board and the connector, and has strong flexibility and can adapt to the design requirements of different circuit boards. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic structural diagram of a board-to-board connection structure provided in an embodiment of the present invention.

[0034] Figure 2 A schematic structural diagram of a connector provided in an embodiment of the present invention.

[0035] Figure 3 A schematic diagram of the structure of a connector and a first circuit board in cooperation with each other provided in one embodiment of the present invention.

[0036] Figures 4 to 13 A flow chart of preparing a board-to-board connection structure provided in one embodiment of the present invention.

[0037] Main component symbols

[0038] Board-to-board connection structure 1000

[0039] First circuit board 1

[0040] First base 11

[0041] The first outer circuit layer 12

[0042] First conductive layer 13

[0043] The first covering layer 14

[0044] The first dielectric layer 15

[0045] First adhesive layer 151

[0046] First insulating layer 152

[0047] Inner circuit layer 16

[0048] Via 17

[0049] First connection pad 18

[0050] Second circuit board 2

[0051] Second base 21

[0052] The second outer wiring layer 22

[0053] The second conductive layer 23

[0054] Second covering layer 24

[0055] Second connection pad 25

[0056] Connector 3

[0057] First electrical connection portion 31

[0058] Second electrical connection portion 33

[0059] Contact 331

[0060] Clamping device 332

[0061] Shrapnel 333

[0062] Connection part 3331

[0063] Shrapnel body 3332

[0064] Housing 32

[0065] End wall 321

[0066] Side wall 322

[0067] Opening 323

[0068] The third conductive layer 4

[0069] Fixing glue 5

[0070] The first distance a

[0071] The second distance b

[0072] Width c

[0073] Intermediate 100

[0074] The first double-sided copper clad laminate 10

[0075] The first copper foil layer 20

[0076] The second copper foil layer 30

[0077] Slot 40

[0078] Electroplating layer 50

[0079] Finished product area A

[0080] Waste Area B

[0081] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0082] The following will be combined with the 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0083] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0084] See also Figures 1 to 3 The embodiment of the present invention provides a board-to-board connection structure 1000, including a first circuit board 1, a second circuit board 2, and a connector 3 electrically connecting the first circuit board 1 and the second circuit board 2. The connector 3 includes a housing 32, a first electrical connection portion 31 located outside the housing 32, and a second electrical connection portion 33 located in the housing 32 and electrically connected to the first electrical connection portion 31.

[0085] The first circuit board 1 includes a first base layer 11 and a first outer circuit layer 12 located on the first base layer 11, and a first conductive layer 13 electrically connected to the first outer circuit layer 12 is provided on the side of the first circuit board 1. The second circuit board 2 includes a second base layer 21 and a second outer circuit layer 22 located on the second base layer 21, and a second conductive layer 23 electrically connected to the second outer circuit layer 22 is provided on the side of the second circuit board 2. The connector 3 is connected to the first conductive layer 13 through the first electrical connection portion 31, the second circuit board 2 is disposed in the housing 32, and the second electrical connection portion 33 is electrically connected to the second outer circuit layer 22 and the second conductive layer 23, thereby realizing the electrical connection between the first circuit board 1 and the second circuit board 2.

[0086] In one embodiment, the first conductive layer 13 and the second conductive layer 23 may both be metal-plated layers. The metal here may be at least one of: copper (Cu); titanium (Ti); nickel (Ni); and gold (Au), preferably copper.

[0087] In one embodiment, the second electrical connection portion 33 includes at least one contact 331 and at least one clamping device 332 disposed in the housing 32 , the contact 331 is electrically connected to the second conductive layer 23 , and the clamping device 332 is electrically connected to the second outer circuit layer 22 .

[0088] In one embodiment, the housing 32 includes an end wall 321, a side wall 322 arranged around the end wall 321, and an opening 323 arranged on the opposite side of the end wall 321. The first electrical connection portion 31 is arranged on the outer side of the end wall 321, and the contact 331 is arranged on the inner side of the end wall 321, and the first electrical connection portion 31 is electrically connected to the contact 331. The clamping device 332 is arranged on the side wall 322. One end of the second circuit board 2 is inserted into the housing 32 through the opening 323, and the clamping device 332 can clamp the two opposite surfaces of the second circuit board 2 to achieve the functions of fixing and electrically connecting, and at the same time electrically connect with the second outer circuit layer 22 on the second circuit board 2. Since the connector 3 is located on the side of the first circuit board 1, when the second circuit board 2 is inserted into the connector 3 from the opening 323, it will not cause an increase in thickness, that is, the overall thickness of the board-to-board connection structure 1000 is reduced, which is conducive to the development of electronic products towards lightness and thinness.

[0089] like Figure 1 and Figure 2As shown, in one embodiment, the housing 32 is generally a hollow rectangular parallelepiped structure, that is, the four sides of the end wall 321 are respectively provided with a side wall 322, and the four side walls 322 are connected end to end to form a frame structure. The opening 323 is provided on the opposite side of the end wall 321 and is a rectangular opening.

[0090] In one embodiment, the clamping device 332 includes two oppositely disposed spring pieces 333, and the two spring pieces 333 are disposed on the two oppositely disposed side walls 322. After the end of the second circuit board 2 is inserted into the housing 32, the two spring pieces 333 are used to clamp the second circuit board 2 from two opposite sides of the second circuit board 2, and the spring pieces 333 abut against the second outer circuit layer 22, thereby achieving fixation and electrical connection.

[0091] In one embodiment, the spring piece 333 includes a connecting portion 3331 disposed on the side wall 322 and a spring piece body 3332 connected to the connecting portion 3331. The two spring piece bodies 3332 disposed opposite to each other bulge from the connecting portion 3331 toward each other. It can be understood that the first distance a between the bulging parts of the two spring piece bodies 3332 disposed opposite to each other is smaller than the second distance b between the two connecting portions 3331. At the same time, the spring piece body 3332 is elastic. When the second circuit board 2 is inserted into the housing 32, the spring piece body 3332 can be bent and deformed toward one side of the side wall 322 with the connecting portion 3331 as the axis. At the same time, the deformation recovery force of the two spring piece bodies 3332 disposed opposite to each other acts on the two opposite sides of the second circuit board 2, and clamps and fixes the second circuit board 2 in the housing 32.

[0092] In one embodiment, after the two relatively arranged spring bodies 3332 are clamped on the two relatively side surfaces of the second circuit board 2, the spring bodies 3332 and the second outer circuit layer 22 are welded together by a welding process, thereby fixing the second circuit board 2. Specifically, a reflow soldering process can be used for welding. At the same time, the contact 331 and the second conductive layer 23 can also be welded together by the above-mentioned welding process. Adding a welding process can improve the connection firmness between the second circuit board 2 and the connector 3.

[0093] In one embodiment, the number of the clamping device 332 is two groups, and the two groups of the clamping device 332 include four spring pieces 333 arranged opposite to each other in pairs, and the four spring pieces 333 are arranged half on the four side walls 322, so that the second circuit board 2 can be clamped and fixed from four aspects, and the stability is stronger. At the same time, according to the design flexibility of the above-mentioned clamping device 332, combined with the actual wiring situation of the second circuit board 2, multi-directional electrical connection can be achieved. For example, for a double-layer board, at least 3 surfaces can be electrically connected (the end surface, upper surface and lower surface of the second circuit board), and at most 5 surfaces can be electrically connected (the end surface, upper surface, lower surface, left side and right side of the second circuit board). Through the above-mentioned position design of the clamping device 332, the connection area between the second circuit board 2 and the connector 3 can be effectively increased, and it is flexible and can be adapted to the design requirements of different circuit boards.

[0094] In one embodiment, the contact 331 and the clamping device 332 are made of conductive materials, which can realize the electrical connection between the second circuit board 2 and the first electrical connection portion 31. Specifically, the conductive material can be a metal sheet or a plastic sheet with conductive metal particles added. In this embodiment, the metal sheet is preferably copper (Cu); titanium (Ti); nickel (Ni); gold (Au); a combination of one or more of Ti, Ni, Au or Cu; or other suitable metals, alloys, or a combination of metals and / or alloys.

[0095] like Figure 1 and Figure 3 As shown, in one embodiment, the first electrical connection portion 31 is electrically connected to the first conductive layer 13 via the third conductive layer 4 .

[0096] In one embodiment, the third conductive layer 4 includes conductive paste or conductive adhesive, specifically solder paste. Specifically, the solder paste can be formed on the first conductive layer 13 by coating, and then the connector 3 is connected; or a light-curing solder ball is implanted on the first conductive layer 13 to connect the connector 3, and then light-curing is performed. In order to increase the area for dispensing glue or solder paste, the area of ​​the first electrical connection portion 31 can be appropriately increased to make the connection and fixation more firm and stable.

[0097] like Figure 3 As shown, in one embodiment, the first outer circuit layer 12 includes a first connection pad 18 located at the edge of the first circuit board 1. The first electrical connection portion 31 extends and covers the first connection pad 18, and the third conductive layer 4 is also located between the first connection pad 18 and the first electrical connection portion 31, thereby effectively electrically connecting the first circuit board 1 and the connector 3 while increasing the firmness and stability of the connection.

[0098] like Figure 1 and Figure 3 As shown, in one embodiment, the surface of the first outer circuit layer 12 is covered with a first covering layer 14, and the first connection pads 18 are exposed to the first covering layer 14. Specifically, the first covering layer 14 may be a solder resist layer.

[0099] like Figure 1 As shown, in one embodiment, the first circuit board 1 is a four-layer board, and the first outer circuit layer 12 is provided on both surfaces of the first base layer 11, and two first conductive layers 13 are correspondingly provided, and the two first conductive layers 13 are respectively electrically connected to the first outer circuit layer 12 on the same side. At the same time, there are also two first electrical connection parts 31, which are respectively provided corresponding to the two first conductive layers 13.

[0100] An inner circuit layer 16 and a first dielectric layer 15 are sequentially disposed on the first base layer 11 , and the inner circuit layer 16 is electrically connected to the first outer circuit layer 12 through a via 17 .

[0101] In one embodiment, the second circuit board 2 further includes a second covering layer 24 disposed on the second outer circuit layer 22. Specifically, the second covering layer 24 may be a solder resist layer. The second outer circuit layer 22 includes a second connection pad 25 located at an edge of the second circuit board 2, and the second connection pad 25 is exposed outside the second covering layer 24. The second connection pad 25 is located in the housing 32 and is electrically connected to the clamping device 332. Specifically, the width c of the second connection pad 25 is related to the setting position of the clamping device 332 in the housing 32, and the width c here refers to the width along the connection direction of the two circuit boards.

[0102] In one embodiment, a fixing glue 5 is filled between the housing 32 and the second circuit board 2. The fixing glue 5 can improve the connection stability between the second circuit board 2 and the connector 3, and can effectively improve the electrical connection effect between the two to avoid a circuit break due to accidental shaking.

[0103] See also Figures 4 to 13 The method for preparing the board-to-board connection structure 1000 provided in an embodiment of the present invention specifically comprises the following steps:

[0104] Step S1, see Figure 4 , a first double-sided copper clad laminate 10 is provided, and the first double-sided copper clad laminate 10 includes the first base layer 11 and a first copper foil layer 20 covering both surfaces of the first base layer 11.

[0105] Step S2, see Figure 5The two first copper foil layers 20 are etched by exposure and development process to prepare the inner circuit layer 16. The first base layer 11 has a via hole 17 formed therein, and the two inner circuit layers 16 are electrically connected through the via hole 17.

[0106] Step S3, see Figure 6 The first dielectric layer 15 and the second copper foil layer 30 are respectively covered on each inner circuit layer 16 to obtain an intermediate body 100. The first dielectric layer 15 includes a first glue layer 151 and a first insulating layer 152, and the first glue layer 151 is located between the inner circuit layer 16 and the first insulating layer 152.

[0107] Step S4, see Figure 7 A groove 40 is opened in each second copper foil layer 30 and the corresponding first dielectric layer 15, so as to divide the intermediate 100 into a finished product area A and a waste area B, wherein the groove 40 does not penetrate the first base layer 11, that is, the finished product area A and the waste area B are connected only through the first base layer 11.

[0108] Step S5, see Figure 8 , a surface metal is electroplated on each of the second copper foil layers 30 to form an electroplated layer 50 , and the electroplated layer 50 extends to the side of the finished product area A to form the first conductive layer 13 .

[0109] Step S6, see Fig. 9 Each of the second copper foil layers 30 and the corresponding electroplating layer 50 is exposed and developed to obtain a first outer circuit layer 12 , and the inner circuit layer 16 on the same side is electrically connected to the first outer circuit layer 12 through a via 17 .

[0110] Step S7, see Fig.10 A first covering layer 14 is covered on the surface of the first outer circuit layer 12 , and the first covering layer 14 may be a solder resist layer.

[0111] When covering the first covering layer 14, it is necessary to consider whether the edge near the first conductive layer 13 needs to be fully covered. If not, the first outer circuit layer 12 at the edge can be exposed. In one embodiment, part of the first outer circuit layer 12 is exposed to the first covering layer 14 to form the first connection pad 18. Step S8, see Fig.11 , removing the portion of the first base layer 11 corresponding to the groove 40, thereby separating the finished product area A and the waste area B to obtain the first circuit board 1.

[0112] Step S9, see Fig.12 , provide the connector 3 , and fix the first electrical connection part 31 on the first conductive layer 13 through the third conductive layer 4 .

[0113] In one embodiment, the third conductive layer 4 includes conductive paste or conductive adhesive, specifically solder paste. Specifically, the solder paste can be formed on the first conductive layer 13 by coating, and then the connector 3 is connected; or a light-curing solder ball is implanted on the first conductive layer 13 to connect the connector 3, and then light-curing is performed. In order to increase the area for dispensing glue or solder paste, the area of ​​the first electrical connection portion 31 can be appropriately increased to make the connection and fixation more firm and stable.

[0114] In one embodiment, the first electrical connection portion 31 extends and covers the first connection pad 18, and the third conductive layer 4 is also located between the first connection pad 18 and the first electrical connection portion 31, thereby effectively electrically connecting the first circuit board 1 and the connector 3 while increasing the firmness and stability of the connection.

[0115] In one embodiment, the first electrical connection portion 31 is a metal plating formed on the housing 32. When the contact area with the first conductive layer 13 needs to be increased, the area of ​​the metal plating needs to be increased, which can be flexibly adjusted according to the actual circuit board wiring structure.

[0116] Step S10, see Fig.13 , a second circuit board 2 is provided. The preparation method of the second circuit board 2 can refer to the preparation steps of the first circuit board 1 (i.e., steps S1 to S8), wherein when the surface of the second outer circuit layer 22 is covered with a second covering layer 24, a portion of the second outer circuit layer 22 is exposed from the second covering layer 24 to form a second connection pad 25.

[0117] Then, the second circuit board 2 is inserted into the housing 32 , so that the second conductive layer 23 is electrically connected to the contact 331 , and the clamping device 332 is electrically connected to the second connection pad 25 .

[0118] In one embodiment, the second circuit board 2 is a four-layer board having two upper and lower second outer circuit layers 22. A set of clamping devices 332 is provided in the housing 32, that is, a spring piece 333 is provided on each of the two oppositely disposed side walls 322. The two spring pieces 333 are clamped and contacted with the second connection pads 25 on the same side, so that the second circuit board 2 can be fixed and the electrical connection of the two surfaces can be achieved. Combined with the electrical connection between the second conductive layer 23 and the contact 331, the electrical connection of the three surfaces can be achieved.

[0119] In another embodiment, two groups of the clamping devices 332 , that is, four spring pieces 333 arranged opposite to each other in pairs, may be disposed in the housing 32 , so as to realize electrical connection between the second circuit board 2 and five surfaces of the connector 3 .

[0120] Step S11, please refer again Figure 1 , a fixing glue 5 is filled in the gap between the housing 32 and the second circuit board 2 to obtain the board-to-board connection structure 1000.

[0121] Filling the fixing glue 5 can make the connection between the housing 32 and the second circuit board 2 more stable.

[0122] In the present application, the first circuit board 1 and the second circuit board 2 include but are not limited to soft boards or hard boards or soft-hard combination boards, and can also be double-sided boards or multi-layer boards with more conductive circuits. The specific number of circuit layers can be designed according to actual needs.

[0123] The board-to-board connection structure provided by the present invention has the following advantages:

[0124] 1. The connector is used to connect the first circuit board and the second circuit board at the side and realize electrical connection at the same time, which ensures that the thickness of the circuit boards will not increase after connection, is conducive to reducing the thickness of the board-to-board connection structure, and is conducive to the development of electronic products towards lighter and thinner.

[0125] 2. The connector has a simple structure and can be electrically connected to the first circuit board through conductive glue or conductive paste. The second circuit board only needs to be inserted into the housing through the opening to be fixedly connected through the clamping device.

[0126] 3. The design of the clamping device and the contact can realize multi-sided electrical connection according to the wiring structure design of the actual circuit board, which can effectively increase the connection area between the second circuit board and the connector, and has strong flexibility and can adapt to the design requirements of different circuit boards.

[0127] In addition, for those skilled in the art, various other corresponding changes and modifications can be made based on the technical concept of the present invention, and all these changes and modifications should fall within the protection scope of the present invention.

Claims

1. A board-to-board connection structure, characterized in that: The device comprises a first circuit board, a second circuit board and a connector electrically connecting the first circuit board and the second circuit board. The connector comprises a shell, a first electrical connection portion located outside the shell, and a second electrical connection portion located in the shell and electrically connected to the first electrical connection portion, the shell comprises an end wall, side walls arranged around the end wall, and an opening arranged on the opposite side of the end wall, the first electrical connection portion is arranged on the outer side of the end wall, the second electrical connection portion comprises at least one contact arranged on the inner side of the end wall and at least one clamping device arranged on the side wall, the first electrical connection portion is electrically connected to the contact, and the clamping device comprises two elastic sheets arranged opposite to each other, each of the elastic sheets comprises a connecting portion arranged on the side wall of the shell and an elastic sheet body connected to the connecting portion, the two elastic sheet bodies arranged opposite to each other bulge from the connecting portion toward each other, and a first distance between the bulging parts of the two elastic sheet bodies arranged opposite to each other is smaller than a second distance between the two connecting portions; The first circuit board includes a first base layer and a first outer circuit layer located on the first base layer, and a first conductive layer electrically connected to the first outer circuit layer is provided on a side surface of the first circuit board; The second circuit board includes a second base layer and a second outer circuit layer located on the second base layer, and an end surface of the second circuit board is provided with a second conductive layer electrically connected to the second outer circuit layer; The connector is connected to the first conductive layer via the first electrical connection portion, the first electrical connection portion is fixed to the first conductive layer via conductive glue or conductive paste, one end of the second circuit board extends into and is disposed in the housing, the contact is electrically connected to the second conductive layer, the two spring sheets clamp the second circuit board and are electrically connected to the second outer circuit layer, so that the second electrical connection portion is electrically connected to the second outer circuit layer.

2. The board-to-board connection structure according to claim 1, characterized in that: The first outer circuit layer includes a first connection pad, the first conductive layer is connected to the first connection pad, and the first electrical connection portion is electrically connected to the first connection pad and the first conductive layer.

3. The board-to-board connection structure according to claim 1, characterized in that: The second outer circuit layer includes a second connection pad, and the spring sheet elastically abuts against the second connection pad.

4. The board-to-board connection structure according to claim 1, characterized in that: A fixing glue is filled between the shell and the second conductive layer.

5. A method for preparing a board-to-board connection structure, characterized in that: The following steps are involved: A first circuit board is provided, wherein the first circuit board comprises a first base layer, a first outer circuit layer provided on at least one surface of the first base layer, and a first conductive layer provided on one side end surface of the first circuit board, wherein the first conductive layer is electrically connected to the first outer circuit layer; A connector is provided, the connector comprising a shell, a first electrical connection portion located outside the shell, and a second electrical connection portion located in the shell and electrically connected to the first electrical connection portion, the shell comprising an end wall, side walls arranged around the end wall, and an opening arranged on the opposite side of the end wall, the first electrical connection portion is arranged on the outer side of the end wall, the second electrical connection portion comprises at least one contact arranged on the inner side of the end wall and at least one clamping device arranged on the side wall, the first electrical connection portion is electrically connected to the contact, the clamping device comprises two elastic sheets arranged opposite to each other, each of the elastic sheets comprises a connecting portion arranged on the side wall of the shell and an elastic sheet body connected to the connecting portion, the two elastic sheet bodies arranged opposite to each other bulge from the connecting portion toward each other, and a first distance between the bulging parts of the two elastic sheet bodies arranged opposite to each other is smaller than a second distance between the two connecting portions; The first electrical connection portion is fixedly and electrically connected to the first conductive layer on the side of the first circuit board by means of conductive glue or conductive paste; A second circuit board is provided, wherein the second circuit board comprises a second base layer and a second outer circuit layer provided on at least one surface of the second base layer, a second conductive layer is provided on an end surface of the second circuit board close to a side of the first circuit board, and the second conductive layer is electrically connected to the second outer circuit layer; One end of the second circuit board is placed in the housing, the contact is electrically connected to the second conductive layer, the second circuit board is clamped between the two spring sheets, the second outer circuit layer is electrically connected to the second electrical connection portion, and the board-to-board connection structure is obtained.

6. The method for preparing the board-to-board connection structure according to claim 5, characterized in that: The first outer circuit layer includes a first connection pad, the first conductive layer is connected to the first connection pad, and the first electrical connection portion is electrically connected to the first connection pad and the first conductive layer.

7. The method for preparing a board-to-board connection structure according to claim 6, characterized in that: The second outer circuit layer includes a second connection pad, and the spring sheet elastically abuts against the second connection pad.

8. The method for preparing a board-to-board connection structure according to claim 5, characterized in that: After placing one end of the second circuit board provided with the second conductive layer in the housing, the method further includes filling fixing glue between the housing and the second circuit board.

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