Flexible circuit board and electronic equipment

Abstract

The utility model provides a flexible circuit board and electronic equipment, and belongs to the technical field of electronics. The through-axis FPC flexible circuit board comprises an FPC body and a metal layer. The FPC body comprises a first wiring layer and a second wiring layer which are stacked, the first wiring layer is used for transmitting electric signals, and the second wiring layer is used for providing reference ground; the metal layer is located on the side, back to the second wiring layer, of the first wiring layer. According to the flexible circuit board provided by the utility model, the wiring width of the second wiring layer can be reduced, so that the narrowing design of the whole flexible circuit board is realized, the structural adaptability of the flexible circuit board, a rotating shaft and electronic equipment is met, and the transmission effect of an electric signal is improved.

Description

Technical Field

[0001] The utility model relates to the field of electronic technology, in particular to a flexible circuit board and electronic equipment. Background Art

[0002] In the related art, there are electronic devices that use hinges to achieve folding, such as flip phones, foldable screen phones, laptops, etc. These electronic devices usually require a flexible printed circuit board (FPC) to pass through the hinge to transmit electrical signals between the two parts of the body.

[0003] However, due to structural limitations of the shaft and electronic equipment, the width of the flexible circuit board that can be accommodated is relatively small, resulting in a relatively large impedance of the flexible circuit board, which affects the transmission effect of the electrical signal. Utility Model Content

[0004] The utility model provides a flexible circuit board and electronic equipment, which can solve the problem that the impedance of the flexible circuit board is large and affects the transmission effect of the electric signal.

[0005] The technical solution is as follows:

[0006] In one aspect, a flexible circuit board is provided, comprising: an FPC body and a metal layer;

[0007] The FPC body includes a first routing layer and a second routing layer arranged in a stacked manner, wherein the first routing layer is used to transmit electrical signals, and the second routing layer is used to provide a reference ground;

[0008] The metal layer is located on a side of the first wiring layer facing away from the second wiring layer.

[0009] In some embodiments, a distance D1 between the metal layer and the first routing layer is smaller than a distance D2 between the first routing layer and the second routing layer.

[0010] In some embodiments, the distance D1 between the metal layer and the first wiring layer ranges from 0.01 mm to 0.03 mm.

[0011] In some embodiments, the metal layer is an electromagnetic interference suppression film structure.

[0012] In some embodiments, the first routing layer includes at least one ground line, and the at least one ground line is electrically connected to the second routing layer; the metal layer is electrically connected to at least one of the at least one ground line and the second routing layer.

[0013] In some embodiments, the FPC body further includes a first covering layer, a first dielectric layer, and a second covering layer stacked in sequence;

[0014] The first covering layer is located between the first routing layer and the metal layer, the first dielectric layer is located between the first routing layer and the second routing layer, and the second covering layer is located on the outer side of the second routing layer facing away from the first routing layer.

[0015] In some embodiments, a thickness d1 of the first covering layer is smaller than a thickness d2 of the first dielectric layer, so that a distance D1 between the metal layer and the first routing layer is smaller than a distance D2 between the first routing layer and the second routing layer.

[0016] In some embodiments, the first routing layer includes at least one ground line, the first dielectric layer is provided with at least one metallized hole, and the at least one ground line is electrically connected to the second routing layer through the at least one metallized hole;

[0017] The first covering layer is provided with at least one window, and the metal layer is electrically connected to the at least one ground line through the at least one window.

[0018] In some embodiments, the first covering layer and the second covering layer are both polyester films or polyimide films;

[0019] The first dielectric layer is a polyimide film.

[0020] In some embodiments, the FPC body further includes a second dielectric layer and a third routing layer;

[0021] The second dielectric layer and the third routing layer are both located between the second routing layer and the second covering layer, and the second dielectric layer faces the second routing layer, while the third routing layer faces the second covering layer.

[0022] On the other hand, an electronic device is provided, which includes the flexible circuit board described in the present utility model.

[0023] In some embodiments, the electronic device further includes a signal amplifier connected to a signal access terminal of the first wiring layer.

[0024] The beneficial effects of the technical solution provided by the utility model include at least:

[0025] In the flexible circuit board of the present invention, a metal layer is arranged on the FPC body, and the metal layer is located on the side of the first routing layer facing away from the second routing layer. Utilizing the conductive properties of the metal layer and the second routing layer, the metal layer and the second routing layer are respectively located on either side of the first routing layer, and the metal layer and the second routing layer respectively form mutual capacitances with the first routing layer. Compared with the mutual capacitance formed by only the second routing layer and the first routing layer, the capacitance of the first routing layer is larger among the mutual capacitances formed by the three conductive layers. Based on the impedance adjustment principle, impedance is inversely proportional to capacitance. Increasing capacitance can reduce the impedance of the second routing layer to below a target level, and impedance is inversely proportional to routing width. Therefore, the routing width of the second routing layer can be narrowed to push the impedance back to the target level, so that the impedance of the second routing layer is maintained at the target level, and the second routing layer can normally transmit electrical signals. Therefore, the utility model can achieve a narrowed routing width of the second routing layer, and thus achieve a narrowed design of the entire flexible circuit board, meet the structural compatibility of the flexible circuit board with the hinge and electronic equipment, and improve the transmission effect of electrical signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic diagram of the laminated structure of the flexible circuit board provided by an embodiment of the present utility model;

[0028] Figure 2 This is a schematic structural diagram of a flexible circuit board provided by an embodiment of the present utility model;

[0029] Figure 3 This is a schematic diagram of the laminated structure of a flexible circuit board provided by another embodiment of the present invention;

[0030] Figure 4 This is a schematic structural diagram of an electronic device in an unfolded state provided by an embodiment of the present utility model;

[0031] Figure 5 It is a structural schematic diagram of an electronic device provided by an embodiment of the present utility model in a folded state.

[0032] The reference numerals in the figures represent respectively:

[0033] 100, flexible circuit board; 200, signal amplifier; 300, first body; 400, second body; 500, hinge structure;

[0034] 1. FPC body;

[0035] 11. First routing layer; 111. Ground line; 12. Second routing layer; 13. First cover layer; 131. Window; 14. First dielectric layer; 141. Metallized hole; 15. Second cover layer; 16. Second dielectric layer; 17. Third routing layer;

[0036] 2. Metal layer. DETAILED DESCRIPTION

[0037] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with certain aspects of the present invention, as detailed in the appended claims.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate directions or positional relationships based on the attached figures. Figure 1 The orientation or positional relationship shown is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] It should be understood that in the present utility model, "electrical connection" can be understood as the physical contact and electrical conduction of components; it can also be understood as the form in which different components in the circuit structure are connected through physical lines such as printed circuit board (PCB) copper foil or wires that can transmit electrical signals. "Communication connection" can refer to electrical signal transmission, including wireless communication connection and wired communication connection. Wireless communication connection does not require a physical medium and does not belong to a connection relationship that limits the product structure. "Connection" and "connected" can both refer to a mechanical connection relationship or a physical connection relationship, that is, A and B are connected or A and B are connected, which means that there is a fastening component (such as screws, bolts, rivets, etc.) between A and B, or A and B are in contact with each other and A and B are difficult to separate.

[0040] Unless otherwise defined, all technical terms used in the embodiments of the present invention have the same meanings as commonly understood by those skilled in the art.

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] On the one hand, combined with Figure 1 and Figure 2 As shown, this embodiment provides a flexible circuit board 100 , which includes an FPC body 1 and a metal layer 2 .

[0043] The FPC body 1 includes a first wiring layer 11 and a second wiring layer 12 arranged in a stacked manner. The first wiring layer 11 is used to transmit electrical signals, and the second wiring layer 12 is used to provide a reference ground.

[0044] The metal layer 2 is located on a side of the first wiring layer 11 facing away from the second wiring layer 12 .

[0045] In the flexible circuit board 100 of this embodiment, a metal layer 2 is arranged on the FPC body 1, and the metal layer 2 is located on the side of the first wiring layer 11 facing away from the second wiring layer 12. By utilizing the conductive properties of the metal layer 2 and the second wiring layer 12, the metal layer 2 and the second wiring layer 12 are respectively located on both sides of the first wiring layer 11. The metal layer 2 and the second wiring layer 12 respectively form mutual capacitance with the first wiring layer 11. Compared with the mutual capacitance formed by only the second wiring layer 12 and the first wiring layer 11, the capacitance of the first wiring layer 11 in the mutual capacitance formed by the three conductive layers is larger. Based on the impedance adjustment principle, the impedance is The impedance of the second wiring layer 12 is inversely proportional to the capacitance. Increasing the capacitance can reduce the impedance of the second wiring layer 12 to below the target level. The impedance is inversely proportional to the wiring width. The wiring width of the second wiring layer 12 can be narrowed to push the impedance back to the target level, so that the impedance of the second wiring layer 12 is maintained at the target level. The second wiring layer 12 can normally transmit electrical signals. Therefore, this embodiment can achieve the narrowing of the wiring width of the second wiring layer 12, and then achieve the narrowing design of the entire flexible circuit board 100, meet the structural compatibility of the flexible circuit board 100 with the hinge and electronic equipment, and improve the transmission effect of electrical signals.

[0046] In some possible implementations, the impedance of the second routing layer 12 is maintained at a target level of 50Ω, which can achieve efficient transmission of electrical signals and can narrow the routing width of the second routing layer 12 by increasing the mutual capacitance of the second routing layer 12.

[0047] It should be noted that the electrical signals transmitted by the second wiring layer 12 include but are not limited to power signals, control signals, data signals, etc., which can realize functions such as power supply, control and data exchange between different components in the electronic device.

[0048] Combine Figure 1As shown, in some embodiments, the distance D1 between the metal layer 2 and the first routing layer 11 is smaller than the distance D2 between the first routing layer 11 and the second routing layer 12 .

[0049] With the above arrangement, the distance D1 between the metal layer 2 and the first wiring layer 11 is smaller, which can further increase the mutual capacitance between the metal layer 2 and the first wiring layer 11 and facilitate narrowing the wiring width of the second wiring layer 12 .

[0050] Furthermore, since the first and second trace layers 11 and 12 are typically encapsulated within the FPC body 1, the spacing D2 between the first and second trace layers 11 and 12 is difficult to adjust due to limitations such as the substrate type and processing technology of the FPC body 1. Changing the design and production parameters of the FPC body 1 incurs significant costs. Therefore, this embodiment employs the addition of a metal layer 2 with a smaller spacing outside the FPC body 1. This increases the mutual capacitance of the second trace layer 12 without requiring changes to the design and production of the FPC body 1. This results in a simple structure, low cost, and low implementation difficulty.

[0051] In some embodiments, the distance D1 between the metal layer 2 and the first wiring layer 11 is in the range of 0.01-0.03 mm. When the distance D1 between the metal layer 2 and the first wiring layer 11 meets the above range, the metal layer 2 has the best effect of increasing the mutual capacitance of the first wiring layer 11, and the cost is controllable, and it is easy to implement and mass-produce.

[0052] Illustratively, the distance D1 between the metal layer 2 and the first wiring layer 11 may be 0.01 mm, 0.012 mm, 0.014 mm, 0.016 mm, 0.018 mm, 0.02 mm, 0.022 mm, 0.024 mm, 0.026 mm, 0.028 mm, or 0.03 mm.

[0053] In some embodiments, the metal layer 2 is a thin film structure for suppressing electromagnetic interference (EMI).

[0054] EMI film is a thin film material specifically used to suppress electromagnetic interference. In electronic devices and communication systems, when current flows through a conductor, an electromagnetic field is generated. These electromagnetic fields may interfere with the normal operation of other electronic devices and cause electromagnetic interference. In order to reduce or eliminate electromagnetic interference, an EMI film can be placed on the surface or inside of the electronic device to isolate the electromagnetic field. In this embodiment, on the one hand, the EMI film structure can be used to electromagnetically isolate the FPC body 1 to improve the anti-interference ability of the FPC body 1. On the other hand, the conductive properties of the metal part in the EMI film structure can be used to form a mutual capacitance with the first wiring layer 11, thereby achieving the purpose of narrowing the wiring width of the second wiring layer 12.

[0055] Combine Figure 2 As shown, in some embodiments, the first routing layer 11 includes at least one ground line 111 , and the at least one ground line 111 is electrically connected to the second routing layer 12 ; the metal layer 2 is electrically connected to at least one of the at least one ground line 111 and the second routing layer 12 .

[0056] Through the above arrangement, the metal layer 2 can be electrically connected to the ground line 111 in the first wiring layer 11 or the second wiring layer 12 to form another reference ground, thereby forming a mutual capacitance with the first wiring layer 11 .

[0057] Exemplarily, the first wiring layer 11 further includes at least one signal line, and the transmission of electrical signals is achieved by using the at least one signal line.

[0058] Combine Figure 1 and Figure 2 As shown, in some embodiments, the FPC body 1 further includes a first covering layer 13 , a first dielectric layer 14 and a second covering layer 15 stacked in sequence.

[0059] The first covering layer 13 is located between the first routing layer 11 and the metal layer 2 . The first dielectric layer 14 is located between the first routing layer 11 and the second routing layer 12 . The second covering layer 15 is located on the outer side of the second routing layer 12 facing away from the first routing layer 11 .

[0060] Through the above arrangement, the first dielectric layer 14 can be used to support and fix the first routing layer 11 and the second routing layer 12, providing a bearing surface for the first routing layer 11 and the second routing layer 12. The first covering layer 13 and the second covering layer 15 respectively cover and protect the first routing layer 11 and the second routing layer 12 to prevent the first routing layer 11 and the second routing layer 12 from being affected by adverse environments such as mechanical damage, moisture and chemical corrosion.

[0061] Combine Figure 1As shown, in some embodiments, the thickness d1 of the first covering layer 13 is less than the thickness d2 of the first dielectric layer 14 , so that the distance D1 between the metal layer 2 and the first wiring layer 11 is less than the distance D2 between the first wiring layer 11 and the second wiring layer 12 .

[0062] Therefore, the distance D1 between the metal layer 2 and the first wiring layer 11 is smaller, which can further increase the mutual capacitance between the metal layer 2 and the first wiring layer 11 , and is conducive to narrowing the wiring width of the second wiring layer 12 .

[0063] Combine Figure 2 As shown, in some embodiments, the first routing layer 11 includes at least one ground line 111, the first dielectric layer 14 is provided with at least one metallized hole 141, and the at least one ground line 111 is electrically connected to the second routing layer 12 through the at least one metallized hole 141; the first covering layer 13 is provided with at least one window 131, and the metal layer 2 is electrically connected to the at least one ground line 111 through the at least one window 131.

[0064] Through the above arrangement, the ground line 111 in the first routing layer 11 can be electrically connected to the second routing layer 12 through the metallized hole 141, and the metal layer 2 can be electrically connected to the ground line 111 to form another reference ground, thereby realizing mutual capacitance with the first routing layer 11.

[0065] In some embodiments, both the first cover layer 13 and the second cover layer 15 are made of polyester film or polyimide film. These materials, such as polyester film or polyimide film, provide excellent insulation and mechanical strength. Furthermore, the first cover layer 13 and the second cover layer 15 can be secured to the outside of the first trace layer 11 or the second trace layer 12 by heat pressing or bonding.

[0066] The first dielectric layer 14 is a polyimide (PI) film.

[0067] Illustratively, first dielectric layer 14 includes a polyimide film layer and an adhesive layer. The polyimide film layer serves as the base material, while the adhesive layer acts as the adhesive that bonds the different layers together. During FPC manufacturing, polyimide and adhesive materials may be used together to create a multilayer flexible circuit board to meet complex circuit designs and meet flexibility requirements. This polyimide film + adhesive layer structure offers superior electrical, thermal, and mechanical properties.

[0068] Combine Figure 3As shown, in some embodiments, the FPC body 1 also includes a second dielectric layer 16 and a third routing layer 17; the second dielectric layer 16 and the third routing layer 17 are both located between the second routing layer 12 and the second covering layer 15, and the second dielectric layer 16 faces the second routing layer 12, and the third routing layer 17 faces the second covering layer 15.

[0069] Through the above arrangement, the FPC body 1 has a three-layer routing structure, wherein the second routing layer 12 serves as a reference ground, and the first routing layer 11 and the third routing layer 17 are used to transmit electrical signals, which can improve the electrical signal transmission performance of the flexible circuit board 100.

[0070] On the other hand, combined Figure 4 and Figure 5 As shown, this embodiment provides an electronic device, which includes the flexible circuit board 100 of the present invention.

[0071] The electronic device of this embodiment adopts the flexible circuit board 100 of the present application and has all the beneficial technical effects of all the embodiments herein.

[0072] In this embodiment, the electronic device is a flippable electronic device, such as a flip electronic device.

[0073] Exemplarily, the flip electronic device includes a flip phone and a foldable screen phone. Among them, a flip phone (also known as a foldable phone) refers to a phone that requires the cover to be opened to see the main display or buttons.

[0074] Foldable Phone: This type of phone allows users to unfold the screen to obtain a larger display area when needed, and can be folded up for easy carrying when not needed.

[0075] In some possible implementations, the electronic device further includes a first body 300, a second body 400, and a hinge structure 500, wherein the first body 300 and the second body 400 are connected via the hinge structure 500. Figure 4 , the electronic device is in the unfolded state, reference Figure 5 , the electronic device is in a folded state.

[0076] One end of the flexible circuit board 100 is located within the first body 300, and the other end of the flexible circuit board 100 is located within the second body 400. The flexible circuit board 100 is used to connect the first electronic component in the first body 300 with the second electronic component in the second body 400. The first and second electronic components use the flexible circuit board 100 to transmit electrical signals.

[0077] Combine Figure 4 and Figure 5As shown, in some embodiments, the electronic device further includes a signal amplifier 200 , and the signal amplifier 200 is connected to the signal access terminal of the first wiring layer 11 .

[0078] Considering that the line loss may be large after the first wiring layer 11 is narrowed, the signal amplifier 200 is arranged at the signal access end of the first wiring layer 11 to increase the amplitude or power of the electrical signal, thereby offsetting the impedance abnormality caused by the increased line loss of the first wiring layer 11.

[0079] It should be noted that, in this application, unless otherwise expressly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. Moreover, the first feature being "above," "above," and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below," "below," and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0081] In the description of this specification, the reference terms "certain embodiments", "one embodiment", "some embodiments", "illustrative embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention.

[0082] The above description is merely an embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A flexible circuit board, characterized in that: The flexible circuit board comprises: an FPC body (1) and a metal layer (2); The FPC body (1) comprises a first wiring layer (11) and a second wiring layer (12) arranged in a stacked manner, wherein the first wiring layer (11) is used to transmit electrical signals, and the second wiring layer (12) is used to provide a reference ground; The metal layer (2) is located on a side of the first wiring layer (11) facing away from the second wiring layer (12).

2. The flexible circuit board according to claim 1, characterized in that: A distance D1 between the metal layer (2) and the first wiring layer (11) is smaller than a distance D2 between the first wiring layer (11) and the second wiring layer (12).

3. The flexible circuit board according to claim 1, wherein: The distance D1 between the metal layer (2) and the first wiring layer (11) has a value range of 0.01-0.03 mm.

4. The flexible circuit board according to claim 1, wherein: The metal layer (2) is a thin film structure for suppressing electromagnetic interference.

5. The flexible circuit board according to claim 1, characterized in that: The first wiring layer (11) comprises at least one ground line (111), and the at least one ground line (111) is electrically connected to the second wiring layer (12); and the metal layer (2) is electrically connected to at least one of the at least one ground line (111) and the second wiring layer (12).

6. The flexible circuit board according to any one of claims 1 to 5, characterized in that: The FPC body (1) further includes a first covering layer (13), a first dielectric layer (14) and a second covering layer (15) stacked in sequence; The first covering layer (13) is located between the first routing layer (11) and the metal layer (2), the first dielectric layer (14) is located between the first routing layer (11) and the second routing layer (12), and the second covering layer (15) is located on the outer side of the second routing layer (12) facing away from the first routing layer (11).

7. The flexible circuit board according to claim 6, characterized in that: The thickness d1 of the first covering layer (13) is smaller than the thickness d2 of the first dielectric layer (14), so that the spacing D1 between the metal layer (2) and the first wiring layer (11) is smaller than the spacing D2 between the first wiring layer (11) and the second wiring layer (12).

8. The flexible circuit board according to claim 6, characterized in that: The first wiring layer (11) includes at least one ground line (111), the first dielectric layer (14) is provided with at least one metallized hole (141), and the at least one ground line (111) is electrically connected to the second wiring layer (12) through the at least one metallized hole (141); The first covering layer (13) is provided with at least one window (131), and the metal layer (2) is electrically connected to the at least one ground line (111) through the at least one window (131).

9. The flexible circuit board according to claim 6, characterized in that: The first covering layer (13) and the second covering layer (15) are both polyester films or polyimide films; The first dielectric layer (14) is a polyimide film.

10. The flexible circuit board according to claim 6, characterized in that: The FPC body (1) further includes a second dielectric layer (16) and a third wiring layer (17); The second dielectric layer (16) and the third routing layer (17) are both located between the second routing layer (12) and the second covering layer (15), and the second dielectric layer (16) faces the second routing layer (12), and the third routing layer (17) faces the second covering layer (15).

11. An electronic device, characterized in that: The electronic device comprises the flexible circuit board (100) according to any one of claims 1 to 10.

12. The electronic device according to claim 11, wherein: The electronic device further comprises a signal amplifier (200), and the signal amplifier (200) is connected to the signal access terminal of the first wiring layer (11).

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