Rigid-Flex Printed Circuit Board and Electronic Device

Abstract

The present application discloses a rigid-flex printed circuit board and an electronic device. The rigid-flex printed circuit board includes a flexible substrate provided with a bending area; a first organic layer disposed on a first surface of the flexible substrate, the first organic layer being provided with a first milling window corresponding to the bending area; a first flexible organic layer disposed within the first milling window and spaced apart from the first organic layer; and a first circuit layer disposed on the first organic layer and / or the first flexible organic layer. The rigid-flex printed circuit board of the present application is provided with a first flexible organic layer in the first milling window for realizing the bending of the rigid-flex printed circuit board. The flexibility of the first flexible organic layer can improve the bending performance of the rigid-flex printed circuit board and prevent the film layer from being easily separated after multiple bendings; in addition, the first flexible organic layer can also be used as a bottom plate to support the fabrication of the first circuit layer, facilitating processing and increasing the reliability of the product.

Description

Technical Field

[0001] This application relates to the field of integrated circuit technology, and particularly to rigid-flex printed circuit boards and electronic devices. Background Art

[0002] A printed circuit board (PCB) is an important electronic component and one of the important components in the electronics industry. Almost every electronic device, from small electronic watches and calculators to large computers, communication electronic devices, and military weapon systems, as long as there are electronic components such as integrated circuits, a printed circuit board is used to achieve electrical interconnection between them. Therefore, the printed circuit board plays an increasingly important role in the field of circuit technology.

[0003] In some printed circuit boards of mobile phone camera modules, Bluetooth headsets, or other consumer electronic products, bending is required, so rigid-flex printed circuit boards are used. However, the bending performance of such rigid-flex printed circuit boards is currently insufficient, and they are easily damaged during the processing, affecting the reliability of the products. Summary of the Invention

[0004] This application provides a rigid-flex printed circuit board and an electronic device to solve the problems of insufficient bending performance and difficult processing of the existing rigid-flex printed circuit board.

[0005] To solve the above technical problems, this application proposes a rigid-flex printed circuit board, including: a flexible substrate provided with a bending area; a first organic layer disposed on the first surface of the flexible substrate, the first organic layer being provided with a first milling window corresponding to the bending area; a first flexible organic layer disposed in the first milling window and spaced from the first organic layer; and a first circuit layer disposed on the first organic layer and / or the first flexible organic layer.

[0006] Optionally, the first flexible organic layer includes a first layer, a second layer, and a third layer stacked, a first circuit layer is disposed on the first layer, and the third layer is bonded to the bending area.

[0007] Optionally, the first layer and the third layer are adhesive layers, the second layer is a polyimide layer; the thickness of the first layer is 2μm - 13μm, the thickness of the second layer is 5μm - 25μm, and the thickness of the third layer is 8μm - 25μm.

[0008] Optionally, the rigid-flex printed circuit board is further provided with through holes and / or blind holes, and the horizontal distance between the through holes and / or blind holes and the first flexible organic layer is greater than or equal to 0.3mm.

[0009] Optionally, the rigid-flex printed circuit board further includes a second organic layer disposed on the second surface of the flexible substrate, the second organic layer being provided with a second milling window corresponding to the bending area; a second flexible organic layer disposed within the second milling window and spaced apart from the second organic layer; and a second circuit layer disposed on the second organic layer and / or the second flexible organic layer.

[0010] Optionally, the flexible substrate includes an insulating base layer, a first base circuit disposed on the first surface of the insulating base layer, and a second base circuit disposed on the second surface of the insulating base layer.

[0011] Optionally, the through hole penetrates through the first circuit layer, the first organic layer, the flexible substrate, the second organic layer, and the second circuit layer.

[0012] Optionally, the printed circuit board is provided with a first blind hole and a second blind hole, the first blind hole penetrating through the first circuit layer and the first organic layer, and the second blind hole penetrating through the second circuit layer and the second organic layer.

[0013] Optionally, the first circuit layer is etched from a first metal layer according to a preset pattern.

[0014] To solve the above technical problems, the present application proposes an electronic device, the electronic device including the rigid-flex printed circuit board described above.

[0015] The present application discloses a rigid-flex printed circuit board, the rigid-flex printed circuit board including: a flexible substrate provided with a bending area; a first organic layer disposed on the flexible substrate, the first organic layer being provided with a first milling window corresponding to the bending area; a first flexible organic layer disposed within the first milling window and spaced apart from the first organic layer; and a first circuit layer disposed on the first organic layer and / or the first flexible organic layer. The first flexible organic layer is disposed in the first milling window of the rigid-flex printed circuit board of the present application to achieve the bending of the rigid-flex printed circuit board. The flexibility of the first flexible organic layer can improve the bending performance of the rigid-flex printed circuit board and prevent the film layer from being easily separated after multiple bends; in addition, the first flexible organic layer can also be used as a bottom plate to support the production of the first circuit layer, which is convenient for processing and increases the reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0017] Figure 1 is a schematic structural diagram of an embodiment of a rigid-flex printed circuit board in the related art;

[0018] Figure 2 It is a schematic structural diagram of an embodiment of the rigid-flex printed circuit board of the present application;

[0019] Figure 3 It is a schematic structural diagram of an embodiment of the flexible substrate of the present application;

[0020] Figure 4 It is a schematic diagram of an embodiment of the first milling window of the present application;

[0021] Figure 5 It is a schematic structural diagram of another embodiment of the rigid-flex printed circuit board of the present application;

[0022] Figure 6 It is a schematic structural diagram of yet another embodiment of the rigid-flex printed circuit board of the present application;

[0023] Figure 7 It is a schematic structural diagram of an embodiment of the electronic device of the present application. Detailed implementation manners

[0024] To enable those skilled in the art to better understand the technical solutions of the present application, the rigid-flex printed circuit board and the electronic device provided by the invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0025] The rigid-flex printed circuit board has the characteristics of being bendable and foldable, so it can maximize the available space of the printed circuit board and reduce the volume of the circuit board in the electronic device. The rigid-flex printed circuit board is often used in some mobile phone camera modules, Bluetooth headsets or other consumer electronic products. However, at present, the bending performance of the rigid-flex printed circuit board is poor, and the film layer is easily separated after multiple bends.

[0026] Please refer to Figure 1 , Figure 1 It is a schematic structural diagram of an embodiment of a related-art rigid-flex printed circuit board. The rigid-flex printed circuit board 100 includes a flexible substrate 11, and the flexible substrate 11 is provided with a bending area. A cover film 12 is provided on the flexible substrate 11, a polypropylene layer 13 is provided on the cover film 12, a milling window 15 is provided in the polypropylene layer 13 corresponding to the bending area, and a copper foil layer 14 is also provided on the polypropylene layer 13. It can be seen from the figure that since the cover film 12 corresponding to the bending area cannot be bonded to the copper foil 14, the bending performance of the bending area is affected. And during the processing of the printed circuit board, the copper foil is easily damaged without support, so it is affected by chemical solutions and tools, which affects the reliability of the product.

[0027] In addition, blind vias 16 are also provided on the rigid-flex printed circuit board, and the blind vias 16 need to penetrate through the cover film 12. The cover film 12 will have a certain impact on drilling, resulting in drilling failure.

[0028] Based on this, the present application proposes a rigid-flex printed circuit board, which can improve the bending performance of the rigid-flex printed circuit board and is easy to process. Please refer to Figure 2 , Figure 3 and Figure 4 , Figure 2 is a schematic structural diagram of an embodiment of the rigid-flex printed circuit board of the present application; Figure 3 is a schematic structural diagram of an embodiment of the flexible substrate of the present application; Figure 4 is a schematic diagram of an embodiment of the first milling window of the present application. The rigid-flex printed circuit board 200 includes a flexible substrate 21, a first organic layer 22, a first circuit layer 23, and a first flexible organic layer 24.

[0029] The flexible substrate 21 includes a first surface 21a and a second surface 21b, and the flexible substrate 21 is further provided with a bending area A. The first organic layer 22 can be disposed on the first surface 21a of the flexible substrate 21, and the first organic layer 22 is provided with a first milling window 221 corresponding to the bending area A; the first flexible organic layer 24 is disposed in the first milling window 221, and the first flexible organic layer 24 is spaced apart from the first organic layer 22. The first circuit layer 23 can be disposed on the first organic layer 22 and / or the first flexible organic layer 24.

[0030] The flexible substrate 21 can be a flexible copper clad laminate (FCCL), and circuits can be provided on the flexible substrate 21. A bending area A is defined on the flexible substrate 21, and the rigid-flex printed circuit board 200 can be bent at a position corresponding to the bending area A.

[0031] The first organic layer 22 can be a thermoplastic resin, such as polypropylene (PP). PP has electrical insulation and chemical resistance, and can protect the circuits on the flexible substrate 21. A first milling window 221 corresponding to the bending area A of the flexible substrate 21 is further provided on the first organic layer 22. The first milling window 221 exposes the bending area A that was originally covered by the first organic layer 22, so that the rigid-flex printed circuit board 200 can be easily bent at the bending area A.

[0032] The first circuit layer 23 is used to achieve electrical connection. The first circuit layer 23 can be etched from a first metal layer according to a preset pattern. The first metal layer can be a metal conductor foil, such as copper foil, aluminum foil, or copper-beryllium alloy foil, etc.

[0033] During the processing, the first surface of the first flexible organic layer 24 can be bonded to the first metal layer, which can prevent delamination of the first metal layer corresponding to the bending area A, resulting in no support under the first metal layer and being damaged during processing and attacked by chemical solutions; the second surface of the first flexible organic layer 24 can be bonded to the bending area A of the flexible substrate 21 to protect the circuit on the bending area A exposed by the first milling window 221.

[0034] Among them, the first flexible organic layer 24 can penetrate into the rigid-flex bonding area of the rigid-flex printed circuit board 200 by 0.2 mm to 1 mm.

[0035] In addition, the thickness of the first flexible organic layer 24 and the thickness of the first organic layer 22 can be equal. The first flexible organic layer 24 and the first organic layer 22 are arranged at intervals, that is, there is a gap between the first flexible organic layer 24 and the first organic layer 22, and the gap can enable the rigid-flex printed circuit board 200 to be bent better. Among them, the gap can be set to 0.1 to 0.3 mm, for example, 0.2 mm.

[0036] In this embodiment, a rigid-flex printed circuit board is provided. The rigid-flex printed circuit board is provided with a first flexible organic layer in the first milling window for realizing the bending of the rigid-flex printed circuit board. The flexibility of the first flexible organic layer can improve the bending performance of the rigid-flex printed circuit board and prevent the film layer separation that is likely to occur after multiple bends; in addition, the first flexible organic layer can also be used as a bottom plate to support the production of the first circuit layer. During the process of etching the first metal layer into the first circuit layer, it can prevent the first metal layer from being damaged and avoid the situation that the rigid-flex printed circuit board is easily attacked by chemical solutions during processing, increasing the reliability of the product.

[0037] Please refer to Figure 5 , Figure 5 which is a schematic structural diagram of another embodiment of the rigid-flex printed circuit board of the present application. The flexible substrate 21 includes an insulating base layer 211 and a first base circuit 212 provided on the first surface of the insulating base layer 211.

[0038] The first base circuit 212 is used to realize the electrical connection of the rigid-flex printed circuit board 200, and the first base circuit 212 can be etched from a metal layer, such as copper foil, according to a preset pattern.

[0039] The first flexible organic layer 24 includes a first layer 241, a second layer 242, and a third layer 243 that are stacked. The first layer 241 and the third layer 243 are adhesive layers, and the adhesive layers of the first layer 241 and the third layer 243 can be epoxy thermosetting adhesive layers or acrylic thermosetting adhesive layers. A first circuit layer 23 can be provided on the first layer 241, and the third layer 243 can be bonded to the first base circuit 212 to protect the electrical circuit on the flexible substrate 21.

[0040] Among them, the thickness of the first layer 241 of the first flexible organic layer 24 can be 2 μm to 13 μm, the thickness of the second layer 242 can be 5 μm to 25 μm, and the thickness of the third layer 243 can be 8 μm to 25 μm.

[0041] Continue to refer to Figure 5 , in this embodiment, the rigid-flex printed circuit board 200 further includes a through hole 26 and a blind hole 25. The blind hole 25 penetrates through the first circuit layer 23 and the first organic layer 22. The blind hole 25 can enable the circuits of the first circuit layer 23 and the flexible substrate 21 to be electrically connected.

[0042] The through hole 26 can penetrate through the first circuit layer 23, the first organic layer 22, and the flexible substrate 21.

[0043] In the rigid-flex printed circuit board of this embodiment, the blind hole 25 and the through hole 26 do not need to penetrate through the cover film, reducing the number of layers that the hole drill penetrates through, eliminating the influence of the hole drill on the cover film, making the through hole 26 or the blind hole 25 not easily fail, and making it easy to deposit electroless copper and electroplated copper on the through hole 26 and the blind hole 25. In addition, the design of the through hole 26 and the blind hole 25 in this embodiment has a low coefficient of thermal expansion in the Z-axis direction, solving the problem of thermal conduction failure of the hole.

[0044] In this embodiment, the horizontal distance between the through hole 26 and the first flexible organic layer 24 can be set to be greater than or equal to 0.3 mm, and the horizontal distance between the blind hole 25 and the first flexible organic layer 24 can be set to be greater than or equal to 0.3 mm, thereby protecting the rigid-flex printed circuit board 200 from being easily damaged.

[0045] Please refer to Figure 6 , Figure 6 is a schematic structural diagram of another embodiment of the rigid-flex printed circuit board of the present application. The rigid-flex printed circuit board 200 in this embodiment further includes a second organic layer 27. The second organic layer 27 is disposed on the second surface 21b of the flexible substrate 21, and the second organic layer 27 is provided with a second milling window 271 corresponding to the bending region A. The second flexible organic layer 29 is disposed in the second milling window 271. The second flexible organic layer 29 is spaced apart from the second organic layer 27. The second circuit layer 28 can be disposed on the second organic layer 27 and / or the second flexible organic layer 29.

[0046] The second circuit layer 28 is used to achieve electrical connection, and the second circuit layer 28 can be etched from a second metal layer according to a preset pattern. The second metal layer can be a metal conductor foil, such as copper foil, aluminum foil, or copper-beryllium alloy foil, etc.

[0047] Further, the flexible substrate 21 in this embodiment includes an insulating base layer 211, a first base circuit 212 disposed on the first surface of the insulating base layer 211, and a second base circuit 213 disposed on the second surface of the insulating base layer 211. The first base circuit 212 and the second base circuit 213 can be etched from a metal conductive layer according to a preset pattern. Among them, the metal conductive layer can include a copper foil layer, an aluminum foil layer, a copper-beryllium alloy foil, etc.

[0048] In this embodiment, the setting of the second flexible organic layer 29 can be the same as that of the first flexible organic layer 24. The second flexible organic layer 29 includes a first layer 291, a second layer 292, and a third layer 293 stacked. The first layer 291 and the third layer 293 are adhesive layers, and the adhesive layers of the first layer 291 and the third layer 293 can be epoxy thermosetting adhesive layers or acrylic thermosetting adhesive layers. A second circuit layer 28 is disposed on the first layer 291, and the third layer 293 can be bonded to the second base circuit 213 to protect the electrical circuits on the flexible substrate 21.

[0049] Among them, the thickness of the first layer 291 of the second flexible organic layer 29 can be 2μm to 13μm, the thickness of the second layer 292 can be 5μm to 25μm, and the thickness of the third layer 293 can be 8μm to 25μm.

[0050] Continue to refer to Figure 6 , the rigid-flex printed circuit board 200 in this embodiment further includes a first blind via 251, a second blind via 252, and a through hole 26. The through hole 26 penetrates through the first circuit layer 23, the first organic layer 22, the flexible substrate 21, the second organic layer 27, and the second circuit layer 28, so as to realize the electrical connection of the first circuit layer 23, the flexible substrate 21, and the second circuit layer 28.

[0051] The first blind via 251 penetrates through the first circuit layer 23 and the first organic layer 22 to enable the electrical connection between the first circuit layer 23 and the first base circuit 212 of the flexible substrate 21; the second blind via 252 penetrates through the second circuit layer 28 and the second organic layer 27 to enable the electrical connection between the second circuit layer 28 and the second base circuit 213 of the flexible substrate 21.

[0052] In this embodiment, the first blind via 251 and the second blind via 252 can be set so that they do not overlap in the vertical position, and the horizontal distances between the first blind via 251, the second blind via 252, and the through hole 26 and the bending region A are greater than or equal to 0.3 mm, further protecting the rigid-flex printed circuit board 200.

[0053] Based on the above-mentioned rigid-flex printed circuit board, the present application also discloses an electronic device. Please refer to Figure 7 , Figure 7It is a schematic structural diagram of an embodiment of the electronic device of the present application. The electronic device 300 includes the rigid-flex printed circuit board 200 as described above.

[0054] In summary, the present application discloses a rigid-flex printed circuit board. A first flexible organic layer can be provided within the first milling window to achieve the bending of the rigid-flex printed circuit board. The flexibility of the first flexible organic layer can improve the bending performance of the rigid-flex printed circuit board and prevent the film layer from being easily separated after multiple bends. In addition, the first flexible organic layer can also be used as a bottom plate to support the fabrication of the first circuit layer, which is convenient for processing and increases the reliability of the product.

[0055] It can be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Additionally, for the sake of convenience in description, only the parts related to the present application rather than all the structures are shown in the drawings. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0056] The terms "first", "second", etc. in the present application are used to distinguish different objects rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0057] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appearing at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0058] The above description is only the implementation manner of the present application and does not limit the patent scope of the present application. Any equivalent structural or equivalent process transformation made by using the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A rigid-flex printed circuit board, characterized in that, The rigid-flex printed circuit board includes: A flexible substrate provided with a bending region, and the flexible substrate includes a first base layer circuit; A first organic layer disposed on the first surface of the flexible substrate and on the first base layer circuit, and the first organic layer is provided with a first milling window corresponding to the bending region; A first flexible organic layer disposed in the first milling window and spaced from the first organic layer; A first circuit layer disposed on the first organic layer and the first flexible organic layer; Wherein, the first flexible organic layer includes a first layer, a second layer and a third layer stacked, the first circuit layer is disposed on the first layer, and the third layer is bonded to the bending region; the first layer and the third layer are adhesive layers, and the second layer is a polyimide layer.

2. The rigid-flex printed circuit board according to claim 1, characterized in that, The thickness of the first layer is 2μm to 13μm, the thickness of the second layer is 5μm to 25μm, and the thickness of the third layer is 8μm to 25μm.

3. The rigid-flex printed circuit board according to claim 1, wherein The rigid-flex printed circuit board is further provided with through holes and / or blind holes, and the horizontal distance between the through holes and / or blind holes and the first flexible organic layer is greater than or equal to 0.3mm.

4. The rigid-flex printed circuit board according to claim 3, wherein The rigid-flex printed circuit board further includes a second organic layer disposed on the second surface of the flexible substrate, and the second organic layer is provided with a second milling window corresponding to the bending region; a second flexible organic layer disposed in the second milling window and spaced from the second organic layer; a second circuit layer disposed on the second organic layer and the second flexible organic layer.

5. The rigid-flex printed circuit board according to claim 4, characterized in that, The flexible substrate further includes an insulating base layer and a second base layer circuit layer, the first base layer circuit layer is disposed on the first surface of the insulating base layer, and the second base layer circuit is disposed on the second surface of the insulating base layer.

6. The rigid-flex printed circuit board according to claim 4, wherein The through hole penetrates through the first circuit layer, the first organic layer, the flexible substrate, the second organic layer and the second circuit layer.

7. The rigid-flex printed circuit board according to claim 4, wherein The printed circuit board is provided with a first blind hole and a second blind hole, the first blind hole penetrates through the first circuit layer and the first organic layer, and the second blind hole penetrates through the second circuit layer and the second organic layer.

8. The rigid-flex printed circuit board according to any one of claims 1-7, characterized in that, The first circuit layer is etched from a first metal layer according to a preset pattern.

9. An electronic device, characterized in that, The electronic device includes the rigid-flex printed circuit board according to any one of claims 1-8.

Images