Method for manufacturing a circuit board and circuit board

Abstract

A manufacturing method of a circuit board, comprising: providing a first circuit substrate, folding two ends of the first circuit substrate to form a first window between the two ends of the first circuit substrate; providing a second circuit substrate, folding two ends of the second circuit substrate to form a second window between the two ends of the second circuit substrate; providing an adhesive sheet, bonding the adhesive sheet to the first circuit substrate and the second circuit substrate, a projection of the adhesive sheet in the first window being spaced apart from the two ends of the first circuit substrate, and a projection of the adhesive sheet in the second window being spaced apart from the two ends of the second circuit substrate; forming a blind hole through the first circuit substrate and the adhesive sheet, and forming a conductive hole in the blind hole, the conductive hole electrically connecting the first circuit substrate and the second circuit substrate. The application further provides a circuit board.

Description

TECHNICAL FIELD

[0001] The present application relates to a circuit board manufacturing method and a circuit board. BACKGROUND

[0002] With the development of electronic products towards high integration and miniaturization, the circuit board needs to be bent in the actual assembly process to avoid related components, so as to reduce the volume of the electronic product. However, the existing circuit board is difficult to realize flexible assembly, and the manufacturing steps of the circuit board are complex. SUMMARY

[0003] A circuit board manufacturing method comprises the following steps: providing a first circuit substrate, the first circuit substrate comprises a first surface and a second surface arranged oppositely, and at least two first adhesive layers are arranged on the first surface; folding the two ends of the first circuit substrate inward with the first surface, so that the two ends of the first circuit substrate are bonded with the first adhesive layers respectively, and the two ends of the first circuit substrate are spaced apart to form a first window; providing a second circuit substrate, the second circuit substrate comprises a third surface and a fourth surface arranged oppositely, and at least two second adhesive layers are arranged on the fourth surface; folding the two ends of the second circuit substrate inward with the fourth surface, so that the two ends of the second circuit substrate are bonded with the second adhesive layers respectively, and the two ends of the second circuit substrate are spaced apart to form a second window; providing an adhesive sheet, bonding the adhesive sheet to the second surface and the third surface, the projection of the adhesive sheet in the first window is spaced apart from the two ends of the first circuit substrate, and the projection of the adhesive sheet in the second window is spaced apart from the two ends of the second circuit substrate; forming a blind hole penetrating through the first circuit substrate and the adhesive sheet, and forming a conductive hole in the blind hole, the conductive hole electrically connecting the first circuit substrate and the second circuit substrate.

[0004] In some embodiments of the present application, a first recess is formed on the second surface of the first circuit substrate, and the projection of the first recess on the first window is located in the first window and spaced apart from the two ends of the first circuit substrate; the adhesive sheet also fills the first recess.

[0005] In some embodiments of the present application, a second recess is formed on the third surface of the second circuit substrate, and the projection of the second recess on the second window is located in the second window and spaced apart from the two ends of the second circuit substrate; the adhesive sheet also fills the second recess.

[0006] In some embodiments of the present application, the first circuit substrate comprises a first dielectric layer, and the second circuit substrate comprises a second dielectric layer, and the materials of the first dielectric layer and the second dielectric layer are flexible materials.

[0007] In some embodiments of the present application, the manufacturing method further comprises: arranging an electronic component in the first window, and the electronic component is connected with the conductive hole.

[0008] A circuit board comprises a first circuit substrate, a second circuit substrate, an adhesive layer and a conductive hole. The first circuit substrate is divided into a first connecting part, first bendable parts located on both sides of the first connecting part and first end parts located on the first bendable parts away from the first connecting part; the second circuit substrate is divided into a second connecting part, second bendable parts located on both sides of the second connecting part and second end parts located on the second bendable parts away from the second connecting part; the adhesive layer is used to bond the first connecting part and the second connecting part, and the first bendable parts and the second bendable parts are arranged at intervals; the conductive hole penetrates through the first circuit substrate and the adhesive layer and is electrically connected with the second circuit substrate; wherein the first circuit substrate comprises a first circuit layer, and the second circuit substrate comprises a second circuit layer; the number of layers of the first circuit layer at the first end parts is twice the number of layers of the first circuit layer at the first bendable parts, and the number of layers of the second circuit layer at the second end parts is twice the number of layers of the second circuit layer at the second bendable parts.

[0009] In some embodiments of the present application, the first circuit substrate further comprises a first cover layer located on the side where the adhesive layer is located; the first circuit substrate is further provided with a first recess, the first recess penetrates through the first cover layer, and the first circuit layer is exposed to the first recess; and the adhesive layer further fills in the first recess.

[0010] In some embodiments of the present application, the second circuit substrate further comprises a second cover layer located on the side where the adhesive layer is located; the second circuit substrate is further provided with a second recess, the second recess penetrates through the second cover layer, and the second circuit layer is exposed to the second recess; and the adhesive layer further fills in the second recess.

[0011] In some embodiments of the present application, the adhesive layer further extends out of the first recess and / or the second recess and extends towards the direction where the first bendable parts and the second bendable parts are located.

[0012] In some embodiments of the present application, the two first end parts are arranged at intervals to form a first window, and the first bendable parts and the first connecting part are exposed to the first window; the circuit board further comprises an electronic component, and the electronic component is located in the first window and connected with the conductive hole.

[0013] The manufacturing method of the circuit board provided by the embodiments of the present application can realize the layer increase of the circuit layers in the first circuit substrate and the second circuit substrate by folding the two ends of the first circuit substrate and the second circuit substrate, and the manufacturing steps are simplified; and the bendability of the circuit board in multiple directions can be realized by bonding the partial areas of the first circuit substrate and the partial areas of the second circuit substrate by the adhesive layer. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The cross-sectional schematic view of the first circuit substrate provided by the embodiments of the present application is shown.

[0015] Figure 2 for folding Figure 1 Cross-sectional view of both ends of the first circuit substrate shown in

[0016] Figure 3 Cross-sectional view of the second circuit substrate provided in the embodiment of the present application.

[0017] Figure 4 for folding Figure 3 Cross-sectional view of both ends of the second circuit substrate shown in

[0018] Figure 5 for disposing an adhesive sheet between Figure 2 the first circuit substrate shown in Figure 4 the second circuit substrate shown in

[0019] Figure 6 for pressing Figure 5 Cross-sectional view of the first circuit substrate, the adhesive sheet, and the second circuit substrate shown in

[0020] Figure 7 Cross-sectional view of the circuit board formed after connecting an electronic component.

[0021] Figure 8 Cross-sectional view of the circuit board provided in another embodiment of the present application.

[0022] Explanation of Main Element Symbols

[0023]

[0024] The following detailed description will further describe the present application with reference to the above-described drawings. DETAILED DESCRIPTION

[0025] In order to more clearly understand the above objects, features and advantages of the present application, the following describes the present application with reference to the attached drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other unless they conflict. In the following description, a number of specific details are set forth in order to provide a thorough understanding of the present application. The described embodiments are merely a part of the present application and are not all the embodiments of the present application.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the description of the specification herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the term "and / or" includes all and any combinations of one or more of the associated listed items.

[0027] In the embodiments of the present application, for the convenience of description but not limitation of the present application, the term "connection" used in the patent application specification and claims of the present application is not limited to physical or mechanical connection, whether direct or indirect. "Up", "down", "above", "below", "left", "right", and the like are only used to indicate relative positional relationship, which changes accordingly when the absolute position of the described object changes.

[0028] Referring to Figures 1 to 7 The manufacturing method of the circuit board 100 can include the following steps.

[0029] Step S1: Referring to Figure 1 A first circuit substrate 10 is provided, which includes a first surface 112 and a second surface 132 arranged oppositely, and at least two first adhesive layers 20 are arranged on the first surface 112.

[0030] The first circuit substrate 10 includes a first dielectric layer 11, a first circuit layer 12, and a first cover layer 13. The first circuit layer 12 is arranged in a stack with the first dielectric layer 11, and the first cover layer 13 covers the first circuit layer 12 and the surface of the first dielectric layer 11 exposed to the first circuit layer 12. The first dielectric layer 11 is located at the first surface 112, and the first cover layer 13 is located at the second surface 132.

[0031] The number of layers of the first circuit layer 12 can be one or more. When the number of layers of the first circuit layer 12 is more, the multiple layers of the first circuit layer 12 can be electrically connected.

[0032] The material of the first dielectric layer 11 can be selected from one of flexible materials such as polyimide (PI), liquid crystal polymer (LCP), and modified polyimide (MPI), so that the first circuit substrate 10 can be bent.

[0033] Step S2: Referring to Figure 2 The two ends of the first circuit substrate 10 are folded inward with the first surface 112 facing inward, so that the two ends of the first circuit substrate 10 are bonded with the first adhesive layers 20 respectively, and the first window 15 is formed between the two ends of the first circuit substrate 10.

[0034] After the two ends of the first circuit substrate 10 are folded, the first circuit layer 12 at the two ends of the first circuit substrate 10 directly realizes layer increasing, without the need for other complex processing steps to realize layer increasing, and without the need for steps of increasing openings, filling conductive materials to realize electrical connection of circuit layers of different layers.

[0035] In the embodiment, the second surface 132 of the first circuit substrate 10 is further provided with a first recess 134, a projection of the first recess 134 on the first window 15 is located in the first window 15 and is spaced apart from the two ends of the first circuit substrate 10.

[0036] In some embodiments, the second surface 132 of the first circuit substrate 10 is further provided with a third recess 136, the first circuit layer 12 is exposed to the third recess 136, and the first circuit layer 12 exposed to the third recess 136 can be used for acting as a connection pad.

[0037] Step S3: please refer to Figure 3 , a second circuit substrate 30 is provided, the second circuit substrate 30 includes a third surface 332 and a fourth surface 312 which are oppositely arranged, and the fourth surface 312 is provided with at least two second adhesive layers 40.

[0038] The second circuit substrate 30 includes a second dielectric layer 31, a second circuit layer 32 and a second cover layer 33, the second circuit layer 32 is stacked with the second dielectric layer 31, and the second cover layer 33 covers the second circuit layer 32 and the surface of the second dielectric layer 31 exposed to the second circuit layer 32. The second dielectric layer 31 is located at the fourth surface 312, and the second cover layer 33 is located at the third surface 332.

[0039] The number of layers of the second circuit layer 32 can be one or more, when the number of layers of the second circuit layer 32 is more, the multiple layers of the second circuit layer 32 can be electrically connected.

[0040] The material of the second dielectric layer 31 can be selected from one of flexible materials such as polyimide (PI), liquid crystal polymer (LCP) and modified polyimide (MPI), so that the second circuit substrate 30 can be bent.

[0041] Step S4: please refer to Figure 4 , the two ends of the second circuit substrate 30 are folded inwardly with the fourth surface 312 inwardly, so that the two ends of the second circuit substrate 30 are bonded with the second adhesive layer 40 respectively, and the two ends of the second circuit substrate 30 are spaced apart to form a second window 35.

[0042] After the two ends of the second circuit substrate 30 are folded, the second circuit layer 32 at the two ends of the second circuit substrate 30 is directly realized to increase the layer without other processing steps.

[0043] In the embodiment, the third surface 332 of the second circuit substrate 30 is further provided with a second recess 334, a projection of the second recess 334 on the second window 35 is located in the second window 35 and is spaced apart from the two ends of the second circuit substrate 30.

[0044] In some embodiments, the third surface 332 of the second circuit substrate 30 is further provided with a fourth recess 336, and the second circuit layer 32 is exposed to the fourth recess 336. The second circuit layer 32 exposed to the fourth recess 336 can be used for acting as a connection pad.

[0045] Step S5: referring to Figure 5 and Figure 6 , a bonding sheet 50 is provided, and the bonding sheet 50 is bonded to the second surface 132 and the third surface 332 and is pressed. The projection of the bonding sheet 50 in the first window 15 is spaced apart from the two ends of the first circuit substrate 10, and the projection of the bonding sheet 50 in the second window 35 is spaced apart from the two ends of the second circuit substrate 30.

[0046] In the present embodiment, the bonding sheet 50 is bonded to the first circuit substrate 10 after being folded and the second circuit substrate 30 after being folded. In other embodiments, the bonding sheet 50 can be bonded to the first circuit substrate 10 and the second circuit substrate 30 first, and then the two ends of the first circuit substrate 10 and the two ends of the second circuit substrate 30 are folded respectively.

[0047] When the first recess 134 is provided on the first circuit substrate 10 and the second recess 334 is provided on the second circuit substrate 30, the bonding sheet 50 is further filled in the first recess 134 and the second recess 334. On the one hand, the thickness of the circuit board 100 can be reduced, and on the other hand, the bonding area of the bonding sheet 50 and the first circuit substrate 10 and the second circuit substrate 30 can be increased, thereby increasing the connection reliability of the first circuit substrate 10 and the second circuit substrate 30.

[0048] The bonding sheet 50 also overflows the first recess 134 and the second recess 334, further increasing the bonding area of the bonding sheet 50 and the first circuit substrate 10 and the second circuit substrate 30. The bonding sheet 50 overflows the first recess 134 and the second recess 334, and the second surface 132 and the third surface 332 are spaced apart.

[0049] In some embodiments, only the first recess 134 can be provided on the first circuit substrate 10, or only the second recess 334 can be provided on the second circuit substrate 30. In some embodiments, the first recess 134 and the second recess 334 can not be provided.

[0050] Step S6: referring to Figure 7 , a blind hole 61 is formed through the first circuit substrate 10 and the bonding sheet 50, and a conductive hole 60 is formed in the blind hole 61. The conductive hole 60 is electrically connected to the first circuit substrate 10 and the second circuit substrate 30, and an electronic component 70 is connected to the conductive hole 60 to realize electrical connection.

[0051] The blind hole 61 is formed by laser etching. Since the first recess 134 is formed on the first circuit substrate 10, the second recess 334 is formed on the second circuit substrate 30, and the adhesive sheet 50 is filled in the first recess 134 and the second recess 334, in the laser etching process, the first dielectric layer 11, the first circuit layer 12 and the adhesive sheet 50 are etched, that is, the types of materials subjected to laser etching are less, and the absorption intensities of different materials to laser wavelength are inconsistent. Therefore, it is easier to control the parameters of laser etching to form more regular blind holes 61.

[0052] In the formation of the blind hole 61, the second circuit layer 32 in the second circuit substrate 30 is exposed to the blind hole 61, so that the conductive hole 60 formed in the blind hole 61 is electrically connected with the second circuit substrate 30. The material of the conductive hole 60 can be copper paste, tin paste, silver paste, alloy, graphene, etc.

[0053] Please refer to Figure 7 The circuit board 100 includes the first circuit substrate 10, the second circuit substrate 30, the adhesive sheet 50 and the conductive hole 60. The adhesive sheet 50 bonds the first circuit substrate 10 and the second circuit substrate 30, and the first circuit substrate 10 and the second circuit substrate 30 are electrically connected through the conductive hole 60.

[0054] The first circuit substrate 10 includes the first dielectric layer 11, the first circuit layer 12 and the first cover layer 13. The first circuit layer 12 is stacked with the first dielectric layer 11, and the first cover layer 13 covers the first circuit layer 12 and the surface of the first dielectric layer 11 exposed to the first circuit layer 12. The second circuit substrate 30 includes the second dielectric layer 31, the second circuit layer 32 and the second cover layer 33. The second circuit layer 32 is stacked with the second dielectric layer 31, and the second cover layer 33 covers the second circuit layer 32 and the surface of the second dielectric layer 31 exposed to the second circuit layer 32. The materials of the first dielectric layer 11 and the second dielectric layer 31 can be flexible materials.

[0055] The first circuit substrate 10 is divided into the first connecting portion Ia, the first bendable portion Ib located on both sides of the first connecting portion Ia, and the first end portion Ic located on the first bendable portion Ib away from the first connecting portion Ia. The two first end portions Ic are spaced apart to form the first window 15, and the first bendable portion Ib and the first connecting portion Ia are exposed to the first window 15. The first end portion Ic is folded by the flat first circuit substrate 10 and bonded by the first adhesive layer 20. The number of layers of the first circuit layer 12 located at the first end portion Ic is twice the number of layers of the first circuit layer 12 located at the first bendable portion Ib.

[0056] The second circuit substrate 30 is divided into a second connecting portion IIa, second bendable portions IIb located on both sides of the second connecting portion IIa, and second end portions IIc located on the second end portions IIc away from the second connecting portion IIa. The two second end portions IIc are spaced apart to form a second opening window 35, and the second bendable portions IIb and the second connecting portion IIa are exposed to the second opening window 35. The second end portion IIc is folded by the flat second circuit substrate 30 and is bonded by the second bonding layer 40. The number of layers of the second circuit layer 32 located at the second end portion IIc is twice the number of layers of the second circuit layer 32 located at the second bendable portion IIb.

[0057] The bonding sheet 50 bonds the first connecting portion Ia and the second connecting portion IIa, and the first opening window 15 and the second opening window 35 are located away from the bonding sheet 50. The first covering layer 13 is located on the side where the bonding sheet 50 is located, and the first circuit substrate 10 further has a first recess 134 penetrating the first covering layer 13, and the first circuit layer 12 is exposed to the first recess 134. The second covering layer 33 is located on the side where the bonding sheet 50 is located, and the second circuit substrate 30 further has a second recess 334 penetrating the second covering layer 33, and the second circuit layer 32 is exposed to the second recess 334. The bonding sheet 50 further fills the first recess 134 and the second recess 334, and the bonding sheet 50 further extends out of the first recess 134 and / or the second recess 334 and extends towards the direction where the first bendable portion Ib and the second bendable portion IIb are located. The division of the first connecting portion Ia and the first bendable portion Ib and the division of the second connecting portion IIa and the second bendable portion IIb are limited by the boundary of the bonding sheet 50.

[0058] The first bendable portion Ib and the second bendable portion IIb are spaced apart, that is, the first bendable portion Ib and the second bendable portion IIb are suspended relative to the bonding sheet 50, and the circuit board 100 can be bent in the area of the first bendable portion Ib and the second bendable portion IIb, thereby facilitating electrical connection with other external electronic elements or circuit boards. For example, in a specific embodiment, by bending in the area of the first bendable portion Ib and the second bendable portion IIb, the two first end portions Ic and the two second end portions IIc of the circuit board 100 can be electrically connected to different areas of a battery board, respectively.

[0059] The conductive hole 60 penetrates the first circuit substrate 10 and the bonding sheet 50, and the conductive hole 60 is connected to the second circuit layer 32 to electrically connect the first circuit substrate 10 and the second circuit substrate 30.

[0060] The circuit board 100 further comprises an electronic element 70 located in the first opening window 15 and connected to the conductive hole 60. The electronic element 70 located in the first opening window 15 can reduce the overall thickness of the circuit board 100.

[0061] In other embodiments, the electronic component 70 can also be disposed in the second window 35, and the conductive hole 60 penetrates the second circuit substrate 30 and the adhesive sheet 50 and is connected with the first circuit layer 12.

[0062] Referring to Figure 8 The embodiment further provides a manufacturing method of the circuit board 100a. The manufacturing method of the circuit board 100a is different from the manufacturing method of the circuit board 100 in the previous embodiment in that the first recess 134 is not formed on the first circuit substrate 10, and the second recess 334 is not formed on the second circuit substrate 30, and the adhesive sheet 50a directly bonds the first cover layer 13 of the first circuit substrate 10 and the second cover layer 33 of the second circuit substrate 30. The manufacturing method of the circuit board 100a provided by the embodiment is beneficial to improving the flatness of the circuit board 100a in the process of pressing the first circuit substrate 10, the adhesive sheet 50a and the second circuit substrate 30.

[0063] Referring to Figure 8 The embodiment further provides a circuit board 100a. The circuit board 100a is different from the circuit board 100 in the previous embodiment in that the first recess 134 is not formed on the first circuit substrate 10, and the second recess 334 is not formed on the second circuit substrate 30, and the adhesive sheet 50a directly bonds the first cover layer 13 of the first circuit substrate 10 and the second cover layer 33 of the second circuit substrate 30.

[0064] The manufacturing method of the circuit board 100, 100a provided by the embodiment is beneficial to increasing the circuit layers in the first circuit substrate 10 and the second circuit substrate 30 by folding two ends of the first circuit substrate 10 and the second circuit substrate 30, and simplifying the manufacturing steps. The adhesive sheet 50 bonds part of the first circuit substrate 10 and part of the second circuit substrate 30, so that the circuit board 100, 100a has the bendability in multiple directions.

[0065] The above embodiments are only used to illustrate the technical solutions of the present application rather than limit the present application. Although the present application is described in detail with reference to the above preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application.

Claims

1. A method for manufacturing a circuit board, characterized in that: The following steps are involved: Providing a first circuit substrate, the first circuit substrate comprising a first surface and a second surface disposed opposite to each other, at least two first adhesive layers being disposed on the first surface; Folding the two ends of the first circuit substrate inward with the first surface facing inward, so that the two ends of the first circuit substrate are respectively bonded to the first adhesive layer, and the two ends of the first circuit substrate are separated to form a first window; Providing a second circuit substrate, the second circuit substrate comprising a third surface and a fourth surface disposed opposite to each other, at least two second adhesive layers being disposed on the fourth surface; Folding the two ends of the second circuit substrate inward with the fourth surface so that the two ends of the second circuit substrate are respectively bonded to the second adhesive layer, and the two ends of the second circuit substrate are spaced apart to form a second window; Providing a bonding sheet, bonding the bonding sheet to the second surface and the third surface, wherein the projection of the bonding sheet within the first window is spaced apart from two ends of the first circuit substrate, and the projection of the bonding sheet within the second window is spaced apart from two ends of the second circuit substrate; as well as A blind hole is formed through the first circuit substrate and the bonding sheet, and a conductive hole is formed in the blind hole, wherein the conductive hole electrically connects the first circuit substrate and the second circuit substrate.

2. The method for manufacturing a circuit board according to claim 1, wherein: A first groove is formed on the second surface of the first circuit substrate. A projection of the first groove on the first window is located within the first window and spaced apart from two ends of the first circuit substrate. The bonding sheet is also filled in the first groove.

3. The method for manufacturing a circuit board according to claim 1 or 2, wherein: A second groove is formed on the third surface of the second circuit substrate. A projection of the second groove on the second window is located within the second window and spaced apart from two ends of the second circuit substrate. The bonding sheet is also filled in the second groove.

4. The method for manufacturing a circuit board according to claim 1, wherein: The first circuit substrate includes a first dielectric layer, the second circuit substrate includes a second dielectric layer, and the first dielectric layer and the second dielectric layer are made of flexible materials.

5. The method for manufacturing a circuit board according to claim 1, wherein: The production method further comprises: An electronic component is arranged in the first window, and the electronic component is connected to the conductive hole.

6. A circuit board, characterized in that: include: A first circuit substrate is divided into a first connecting portion, first bendable portions located on both sides of the first connecting portion, and a first end portion of the first bendable portion away from the first connecting portion; The second circuit substrate is divided into a second connecting portion, second bendable portions located on both sides of the second connecting portion, and a second end portion located on the second bendable portion away from the second connecting portion; a bonding sheet for bonding the first connecting portion and the second connecting portion, wherein the first bendable portion and the second bendable portion are spaced apart from each other; as well as a conductive hole, passing through the first circuit substrate and the bonding sheet, and electrically connected to the second circuit substrate; The first circuit substrate includes a first circuit layer, and the second circuit substrate includes a second circuit layer; the number of layers of the first circuit layer located at the first end is twice the number of layers of the first circuit layer located at the first bendable portion, and the number of layers of the second circuit layer located at the second end is twice the number of layers of the second circuit layer located at the second bendable portion.

7. The circuit board according to claim 6, wherein: The first circuit substrate further includes a first covering layer, which is located on the side where the bonding sheet is located; the first circuit substrate further includes a first groove, which passes through the first covering layer, and the first circuit layer is exposed in the first groove; the bonding sheet is also filled in the first groove.

8. The circuit board according to claim 7, wherein: The second circuit substrate also includes a second covering layer, which is located on the side where the bonding sheet is located; the second circuit substrate also has a second groove, which passes through the second covering layer, and the second circuit layer is exposed in the second groove; the bonding sheet is also filled in the second groove.

9. The circuit board according to claim 8, wherein: The bonding sheet also overflows the first groove and / or the second groove and extends toward the direction where the first bendable portion and the second bendable portion are located.

10. The circuit board according to claim 6, wherein: The two first end portions are spaced apart to form a first window, and the first bendable portion and the first connecting portion are exposed in the first window; the circuit board further includes an electronic component, which is located in the first window and connected to the conductive hole.

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