CN112702831A

CN112702831A - Rigid-flex printed circuit board and electronic equipment

Info

Publication number: CN112702831A
Application number: CN201911008531.4A
Authority: CN
Inventors: 邓先友; 刘金峰; 向付羽; 许圣威; 张河根
Original assignee: Shennan Circuit Co Ltd
Current assignee: Shennan Circuit Co Ltd
Priority date: 2019-10-22
Filing date: 2019-10-22
Publication date: 2021-04-23

Abstract

The application discloses a flex-rigid printed circuit board and an electronic device, wherein the flex-rigid printed circuit board comprises a flexible substrate provided with a bending area; the first organic layer is arranged on the first surface of the flexible substrate and provided with a first milling window corresponding to the bending area; the first flexible organic layer is arranged in the first milling window and is arranged at an interval with the first organic layer; and a first circuit layer disposed on the first organic layer and/or the first flexible organic layer. The application discloses flex-rigid printed circuit board sets up first flexible organic layer at first window of milling for realize the buckling of flex-rigid printed circuit board. The flexibility of the first flexible organic layer can improve the bending performance of the rigid-flex printed circuit board, and the film layer separation is prevented from easily occurring after multiple times of bending; in addition, the first flexible organic layer can also be used as a bottom plate to support the manufacture of the first circuit layer, so that the processing is convenient, and the reliability of the product is improved.

Description

Rigid-flex printed circuit board and electronic equipment

Technical Field

The present application relates to the field of integrated circuit technology, and more particularly, to a flex-rigid printed circuit board and an electronic device.

Background

Printed Circuit Boards (PCBs) are important electronic components, and are one of the important components in the electronics industry. Almost every kind of electronic equipment, as small as electronic watches, calculators, as large as computers, communication electronics, military weaponry systems, requires printed circuit boards for electrical interconnection as long as there are electronic components such as integrated circuits. Printed circuit boards are therefore increasingly important in the field of circuit technology.

The printed circuit board of some cell-phone camera module, bluetooth headset or other consumer electronics products need buckle, consequently can apply to rigid flex printed circuit board, but the performance of buckling of this type of rigid flex printed circuit board exists not enoughly at present, and is impaired easily in the course of working, has influenced the reliability of product.

Disclosure of Invention

The application provides flex-rigid printed circuit board and electronic equipment to solve the problem that prior art flex-rigid printed circuit board bending performance is not enough and is difficult for processing.

In order to solve the above technical problem, the present application provides a rigid-flex printed circuit board, including: a flexible substrate provided with a bending region; the first organic layer is arranged on the first surface of the flexible substrate and provided with a first milling window corresponding to the bending area; the first flexible organic layer is arranged in the first milling window and is arranged at an interval with the first organic layer; and a first circuit layer disposed on the first organic layer and/or the first flexible organic layer.

Optionally, the first flexible organic layer includes a first layer, a second layer, and a third layer stacked on the first layer, the first layer is provided with a first circuit layer, and the third layer is bonded to the bending region.

Optionally, the first layer and the third layer are glue layers, and the second layer is a polyimide layer; the first layer has a thickness of 2 to 13 μm, the second layer has a thickness of 5 to 25 μm, and the third layer has a thickness of 8 to 25 μm.

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

Optionally, the rigid-flex printed circuit board further includes a second organic layer, the second organic layer is 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; the second flexible organic layer is arranged in the second milling window and is arranged at intervals with the second organic layer; and a second line layer disposed on the second organic layer and/or the second flexible organic layer.

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

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.

Optionally, 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.

Optionally, the first circuit layer is formed by etching the first metal layer according to a preset pattern.

In order to solve the technical problem, the present application provides an electronic device, which includes the above rigid-flex printed circuit board.

The application discloses rigid-flex printed circuit board, rigid-flex printed circuit board including: a flexible substrate provided with a bending region; the first organic layer is arranged on the flexible substrate and provided with a first milling window corresponding to the bending area; the first flexible organic layer is arranged in the first milling window and is arranged at an interval with the first organic layer; and a first circuit layer disposed on the first organic layer and/or the first flexible organic layer. The application discloses flex-rigid printed circuit board sets up first flexible organic layer at first window of milling for realize the buckling of flex-rigid printed circuit board. The flexibility of the first flexible organic layer can improve the bending performance of the rigid-flex printed circuit board, and the film layer separation is prevented from easily occurring after multiple times of bending; in addition, the first flexible organic layer can also be used as a bottom plate to support the manufacture of the first circuit layer, so that the processing is convenient, and the reliability of the product is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of a structure of an embodiment of a prior art rigid-flex printed circuit board;

FIG. 2 is a schematic structural view of an embodiment of the flex-rigid printed circuit board of the present application;

FIG. 3 is a schematic structural diagram of an embodiment of a flexible substrate according to the present application;

FIG. 4 is a schematic view of an embodiment of a first milled window of the present application;

FIG. 5 is a schematic structural view of another embodiment of a flex-rigid printed circuit board of the present application;

FIG. 6 is a schematic structural view of a further embodiment of the rigid-flex printed circuit board of the present application;

fig. 7 is a schematic structural diagram of an embodiment of an electronic device according to the present application.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present application, the rigid flexible printed circuit board and the electronic device provided by the present invention are further described in detail below with reference to the accompanying drawings and the detailed description.

The rigid-flex printed circuit board has the characteristics of being bendable and foldable, so that the available space of the printed circuit board can be maximally improved, and the volume of the electronic equipment occupied by the circuit board is reduced. A flex-rigid printed circuit board is often used in some mobile phone camera modules, Bluetooth earphones or other consumer electronic products, but the flex-rigid printed circuit board has poor bending performance at present, and the film layer is easily separated after being bent for many times.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of a rigid-flex printed circuit board in the related art. The rigid-flex printed circuit board 100 includes a flexible substrate 11, and the flexible substrate 11 is provided with a bending region. The flexible substrate 11 is provided with a covering film 12, the covering film 12 is provided with a polypropylene layer 13, the polypropylene layer 13 is provided with a milling window 15 corresponding to a bending area, and the polypropylene layer 13 is further provided with a copper foil layer 14. As can be seen from the figure, the coverlay film 12 corresponding to the bending region cannot be bonded to the copper foil 14, and the bending performance of the bending region is affected. And the copper foil is easy to be damaged because of no support in the process of processing the printed circuit board, thereby being affected by the tool of chemical liquid medicine and the reliability of the product.

In addition, the rigid-flex printed circuit board is also provided with a blind hole 16, and the blind hole 16 needs to penetrate through the covering film 12. The cover film 12 may have an effect on the drilling, resulting in a drilling failure.

Based on this, this application provides a rigid-flex printed circuit board, can improve rigid-flex printed circuit board's bending performance to easy processing. Referring to fig. 2, fig. 3 and fig. 4, fig. 2 is a schematic structural diagram of an embodiment of the rigid-flex printed circuit board of the present application; FIG. 3 is a schematic structural diagram of an embodiment of a flexible substrate according to the present application; FIG. 4 is a schematic view of an embodiment of a first milled window of the present application. The rigid-flex printed circuit board 200 includes a flexible substrate 21, a first organic layer 22, a first wiring layer 23, and a first flexible organic layer 24.

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 region a. The first organic layer 22 may be disposed on the first surface 21a of the flexible substrate 21, the first organic layer 22 being provided with a first milling window 221 corresponding to the bending region a; the first flexible organic layer 24 is disposed within the first mill window 221, and the first flexible organic layer 24 is spaced apart from the first organic layer 22. The first wiring layer 23 may be disposed on the first organic layer 22 and/or the first flexible organic layer 24.

The Flexible substrate 21 may be a Flexible Copper Clad Laminate (FCCL), and the Flexible substrate 21 may have a circuit disposed thereon. A bending region a is defined on the flexible substrate 21, and the rigid-flexible printed circuit board 200 can be bent at a position corresponding to the bending region a.

The first organic layer 22 may be a thermoplastic resin, such as polypropylene (PP), which has electrical insulation and chemical resistance and can protect the wires on the flexible substrate 21. The first organic layer 22 is further provided with a first milling window 221 corresponding to the bending region a of the flexible substrate 21. The first milling window 221 exposes the bending region a originally covered by the first organic layer 22, so that the rigid-flex printed circuit board 200 can be easily bent in the bending region a.

The first wiring layer 23 is used to realize electrical connection. The first circuit layer 23 may be etched from the first metal layer according to a predetermined pattern. The first metal layer may be a metal conductor foil such as copper foil, aluminum foil, or copper-beryllium alloy foil.

In the processing process, the first surface of the first flexible organic layer 24 can be bonded with the first metal layer, so that the first metal layer corresponding to the bending region a can be prevented from being layered, and no support is arranged below the first metal layer, so that the first metal layer is damaged in the processing process and is attacked by chemical liquid medicine; the second surface of the first flexible organic layer 24 may be bonded to the bending region a of the flexible substrate 21, so as to protect the circuit on the bending region a exposed by the first milling window 221.

Wherein, the first flexible organic layer 24 can be deep into the flex-rigid region of the flex-rigid printed circuit board 200 by 0.2mm to 1 mm.

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

This embodiment provides a rigid-flex printed circuit board, and this rigid-flex printed circuit board is provided with first flexible organic layer in first milling window for realize the buckling of 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 the film separation which is easy to occur after multiple times of bending is prevented; in addition, first flexible organic layer can also support the preparation on first circuit layer as the bottom plate, and at the in-process that becomes first circuit layer with first metal level sculpture, can prevent that first metal level is damaged, has avoided the condition appearance that receives the attack of chemical liquid easily in the rigid-flex printed circuit board processing, increases the reliability of product.

Referring to fig. 5, fig. 5 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 insulation base layer 211 and a first base circuit 212 disposed on a first surface of the insulation base layer 211.

The first base layer circuit 212 is used to electrically connect the rigid-flex printed circuit board 200, and the first base layer circuit 212 may be formed by etching a metal layer, such as a copper foil, according to a predetermined pattern.

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 may be epoxy thermosetting adhesive layers or acrylic thermosetting adhesive layers. The first layer 241 may have the first wiring layer 23 disposed thereon, and the third layer 243 may be bonded to the first base wiring 212, thereby protecting the electric wiring on the flexible substrate 21.

Wherein, the first layer 241 of the first flexible organic layer 24 may have a thickness of 2 μm to 13 μm, the second layer 242 may have a thickness of 5 μm to 25 μm, and the third layer 243 may have a thickness of 8 μm to 25 μm.

With continued reference to fig. 5, the rigid-flex printed circuit board 200 of the present embodiment further includes through holes 26 and blind holes 25. The blind via 25 penetrates the first wiring layer 23 and the first organic layer 22. The blind via 25 may enable electrical connection between the first wiring layer 23 and the wiring of the flexible substrate 21.

The via hole 26 may penetrate the first wiring layer 23, the first organic layer 22, and the flexible substrate 21.

In the flex-rigid printed circuit board of the present embodiment, the blind holes 25 and the through holes 26 do not need to penetrate through the cover film, the number of layers through which the drill passes is reduced, the influence of the drill on the cover film is eliminated, the through holes 26 or the blind holes 25 are not easily invalidated, and the through holes 26 and the blind holes 25 are easily deposited with chemical copper and electrolytic copper. In addition, the design of the through hole 26 and the blind hole 25 in the embodiment enables the expansion coefficient of the Z axis to be low, and solves the problem of thermal conduction failure of the hole.

In this embodiment, the horizontal distance between the through hole 26 and the first flexible organic layer 24 is greater than or equal to 0.3mm, and the horizontal distance between the blind hole 25 and the first flexible organic layer 24 is greater than or equal to 0.3mm, so that the rigid-flex printed circuit board 200 is protected from being damaged.

Referring to fig. 6, fig. 6 is a schematic structural diagram of a flex-rigid printed circuit board according to another embodiment 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 mill window 271 corresponding to the bending region a. The second flexible organic layer 29 is disposed within the second mill window 271. The second flexible organic layer 29 is spaced apart from the second organic layer 27. The second line layer 28 may be disposed on the second organic layer 27 and/or the second flexible organic layer 29.

The second circuit layer 28 is used for realizing electrical connection, and the second circuit layer 28 may be etched from the second metal layer according to a predetermined pattern. The second metal layer may be a metal conductor foil such as copper foil, aluminum foil, or copper-beryllium alloy foil.

Further, the flexible substrate 21 in the present embodiment includes an insulation base layer 211, and a first base layer circuit 212 disposed on a first surface of the insulation base layer 211 and a second base layer circuit 213 disposed on a second surface of the insulation base layer 211. The first and

second base circuits

212 and 213 may be formed by etching a metal conductive layer according to a predetermined pattern, wherein the metal conductive layer may include a copper foil layer, an aluminum foil layer, a copper-beryllium alloy foil, and the like.

The arrangement of the second flexible organic layer 29 in this embodiment may be the same as the arrangement 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 arranged in a stack. 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 may be epoxy thermosetting adhesive layers or acrylic thermosetting adhesive layers. The second line layer 28 is disposed on the first layer 291, and the third layer 293 may be bonded to the second base line 213, thereby protecting the electric lines on the flexible substrate 21.

The first layer 291 of the second flexible organic layer 29 may have a thickness of 2 to 13 μm, the second layer 292 may have a thickness of 5 to 25 μm, and the third layer 293 may have a thickness of 8 to 25 μm.

With continued reference to fig. 6, the rigid-flex printed circuit board 200 in this embodiment further includes a first blind hole 251, a second blind hole 252, and a through hole 26. The via hole 26 penetrates the first wiring layer 23, the first organic layer 22, the flexible substrate 21, the second organic layer 27, and the second wiring layer 28, thereby achieving electrical connection of the first wiring layer 23, the flexible substrate 21, and the second wiring layer 28.

The first blind via 251 penetrates through the first circuit layer 23 and the first organic layer 22 to electrically connect the first circuit layer 23 and the first base layer circuit 212 of the flexible substrate 21; the second blind via 252 penetrates the second circuit layer 28 and the second organic layer 27 to electrically connect the second circuit layer 28 and the second base circuit 213 of the flexible substrate 21.

In this embodiment, the first blind hole 251 and the second blind hole 252 may be set not to overlap in a vertical position, and the horizontal distance between the first blind hole 251, the second blind hole 252, and the through hole 26 and the bending region a is greater than or equal to 0.3mm, so as to further protect the rigid-flex printed circuit board 200.

Based on the rigid-flex printed circuit board, the application also discloses an electronic device. Referring to fig. 7, fig. 7 is a schematic structural diagram of an embodiment of an electronic device according to the present application. Electronic device 300 includes flex-rigid printed circuit board 200 as described above.

In summary, the application discloses a rigid-flex printed circuit board, can set up first flexible organic layer in first window of milling for realize the buckling of 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 the film layer separation is prevented from easily occurring after multiple times of bending; in addition, the first flexible organic layer can also be used as a bottom plate to support the manufacture of the first circuit layer, so that the processing is convenient, and the reliability of the product is improved.

It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not limiting of the application. In addition, for convenience of description, only a part of structures related to the present application, not all of the structures, are shown in the drawings. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first", "second", etc. in this application are used to distinguish between different objects and not to describe a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The above description is only for the purpose of illustrating embodiments of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application or are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.

Claims

1. A flex-rigid printed circuit board, comprising:

a flexible substrate provided with a bending region;

the first organic layer is arranged on the first surface of the flexible substrate and provided with a first milling window corresponding to the bending area;

the first flexible organic layer is arranged in the first milling window and is arranged at an interval with the first organic layer;

a first line layer disposed on the first organic layer and/or the first flexible organic layer.

2. The flex-rigid printed circuit board of claim 1, wherein the first flexible organic layer comprises a first layer, a second layer and a third layer arranged in a stack, the first layer having the first circuit layer disposed thereon, the third layer being bonded to the bend region.

3. The rigid-flex printed circuit board of claim 2, wherein the first layer and the third layer are glue layers, the second layer is a polyimide layer; the first layer has a thickness of 2 to 13 μm, the second layer has a thickness of 5 to 25 μm, and the third layer has a thickness of 8 to 25 μm.

4. The flex-rigid printed circuit board according to claim 2, further provided with through holes and/or blind holes, the horizontal distance of the through holes and/or blind holes to the first flexible organic layer being greater than or equal to 0.3 mm.

5. The flex-rigid printed circuit board according to claim 4, further comprising a second organic layer disposed on the second surface of the flexible substrate, the second organic layer being provided with a second mill window corresponding to the bending region; the second flexible organic layer is arranged in the second milling window and is arranged at intervals with the second organic layer; a second line layer disposed on the second organic layer and/or the second flexible organic layer.

6. The flex-rigid printed circuit board of claim 5, wherein the flexible substrate comprises a dielectric base layer and a first base layer trace disposed on a first surface of the dielectric base layer and a second base layer trace disposed on a second surface of the dielectric base layer.

7. The flex-rigid printed circuit board of claim 5, wherein the via hole extends through the first circuit layer, the first organic layer, the flexible substrate, the second organic layer, and the second circuit layer.

8. The flex-rigid printed circuit board of claim 5, wherein the printed circuit board is provided with first and second blind holes, the first blind hole passing through the first circuit layer and the first organic layer, the second blind hole passing through the second circuit layer and the second organic layer.

9. The flex-rigid printed circuit board according to any one of claims 1 to 8, wherein the first wiring layer is etched from the first metal layer in a predetermined pattern.

10. An electronic device characterized in that it comprises a rigid-flex printed circuit board according to any one of claims 1 to 9.