CN115623668A - Flexible printed circuit board structure and communication device - Google Patents

Abstract

The invention provides a flexible board structure and a communication device, which are applied to the technical field of communication. The flexible printed circuit board comprises a flexible printed circuit board structure and a flexible printed circuit board structure, wherein the flexible printed circuit board structure comprises a dynamic bending part and a static bending part, one end of the dynamic bending part is connected with the static bending part, and the dynamic bending part comprises: the RF routing area is internally provided with a first dielectric layer; the non-RF wiring area is internally provided with a second dielectric layer; the material corresponding to the first dielectric layer comprises a high-frequency base material, and the material corresponding to the second dielectric layer comprises a conventional base material. The flexible printed circuit board structure is partitioned at the dynamic bending part, and wires are wired in a partitioned mode according to different signal transmission performance requirements. Therefore, the thickness of the bending area can be reduced, the bending performance is improved, and the problems of crosstalk and loss of routing in the same area can be solved.

Description

Flexible printed circuit board structure and communication device

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a flexible printed circuit board structure and a communications device.

Background

The mobile phone, the tablet computer and other terminal devices are developing towards the full screen direction, and in order to improve the screen occupation ratio of the front side of the terminal device, the flexible screen is usually formed by bending a communication panel. In market promotion, the mobile phone with the folding screen is popular with consumers. With the deep application of 4G, the requirement of consumers on the signal transmission capability of products is increased. The existing PI material folding screen can not meet the transmission requirement of the RF signal. High frequency materials must be used to improve the performance of the product. The transmission loss is too large to meet the signal transmission requirement when the traditional PI material is used.

In the related art, the FPC mostly uses high frequency materials such as LCP, MPI, etc. as a base material to realize signal transmission.

However, the minimum thickness of these high-frequency materials is mostly 14um, and the whole thickness is too big when using multilayer to walk the line, and the performance of buckling is not good and it is easy to cross talk to walk the line with the region.

Therefore, it is desirable to provide a flexible board structure that can satisfy the signal transmission requirement and has good bending performance.

Disclosure of Invention

In view of this, an object of the present invention is to provide a flexible printed circuit board structure and a communication device, so as to implement partitioned routing, improve the bending performance of a bending area, and improve crosstalk of routing in the same area.

In a first aspect, an embodiment of the present invention provides a flexible printed circuit board structure, including: dynamic kink and static kink, the one end of dynamic kink with static kink is connected, the dynamic kink includes:

the RF wiring area is internally provided with a first dielectric layer;

the non-RF wiring area is internally provided with a second dielectric layer;

the material corresponding to the first dielectric layer comprises a high-frequency base material, and the material corresponding to the second dielectric layer comprises a conventional base material.

In one possible implementation, the RF routing area includes:

the first copper-clad plate comprises a first dielectric layer and a first conducting layer, wherein the first dielectric layer is arranged on the first conducting layer;

the covering film layer covers the outer wall of the first copper-clad plate.

In one possible embodiment, the non-RF routing area is disposed on one side of the RF routing area, and the non-RF routing area includes:

the second copper-clad plate comprises second to fourth conducting layers and a second dielectric layer; a third conducting layer and a second conducting layer are sequentially arranged above the fourth conducting layer; a second dielectric layer is arranged between the second conducting layer and the third conducting layer, and the second dielectric layer is arranged between the fourth conducting layer and the third conducting layer;

and the covering film layer covers the outer wall of the second copper-clad plate.

In one possible embodiment, the static bend comprises:

the second copper-clad plate comprises first to fourth conducting layers and a dielectric layer, and the second conducting layer, the third conducting layer, the first conducting layer and the fourth conducting layer are sequentially arranged from bottom to top; the dielectric layers comprise the first dielectric layer and the second dielectric layer;

and the covering film layer covers the outer wall of the third copper-clad plate.

In one possible embodiment, the first dielectric layer is disposed between the third conductive layer and the first conductive layer;

the second dielectric layer is arranged between the second conducting layer and the third conducting layer, and between the first conducting layer and the fourth conducting layer.

In one possible embodiment, the dynamic bending part is one or more.

In one possible embodiment, the first to nth conductive layers are each provided with a through hole, and the through holes are plated with copper so as to electrically connect the first to nth conductive layers.

In one possible embodiment, the material corresponding to the first dielectric layer includes at least one of LCP, MPI, PTFE, PPS.

In a possible implementation manner, the material corresponding to the second dielectric layer includes PI.

In a second aspect, an embodiment of the present invention provides a communication device, including the above flexible printed circuit board structure.

The embodiment of the invention provides a flexible printed circuit board structure and a communication device. Therefore, the thickness of the bending area can be reduced, the bending performance is improved, the loss is reduced, and the crosstalk problem of routing in the same area can be improved.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic diagram of a flexible printed circuit board according to an embodiment of the present invention;

FIG. 2 is a side view of a flexible printed circuit board according to an embodiment of the present invention;

fig. 3 is a schematic cross-sectional view illustrating an RF trace area on a dynamic bending portion of a flexible printed circuit board according to an embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of a non-RF trace region on a dynamic bending portion of a flexible printed circuit board according to an embodiment of the present invention;

fig. 5 is a schematic cross-sectional structure diagram of a static bending portion in a flexible printed circuit board structure according to an embodiment of the present invention.

Icon: 1-dynamic bending part; 2-static bending part; 3-RF routing area; 4-non-RF routing area; 5-covering the film layer; 6-a first dielectric layer; 7-a second dielectric layer; 8-a first conductive layer; 9-a second conductive layer; 10-a third conductive layer; 11-fourth conductive layer.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying 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 invention.

To facilitate a better understanding of the present application by those skilled in the art, a brief description of the technical terms involved in the present application will be given below.

The flexible circuit board structure is a flexible circuit board used for being connected with other circuit boards; in the present application, the flexible board includes, but is not limited to, an FPC flexible board.

The dynamic bending part is a part with high bending frequency in the soft board structure.

And the static bending part is a part with low bending frequency in the soft board structure.

And the RF wiring area is an area of the flexible board structure for wiring the radio frequency circuit. In order to meet the transmission speed requirement of Radio Frequency (RF) circuit, high frequency material is used as the substrate in the area.

The non-RF routing area, which is a conventional circuit routing area, has a lower signal transmission speed than the RF circuit.

It should be noted that, in the present application, the terms "first", "second", "third", "fourth", etc. are used for distinguishing similar objects, and do not necessarily describe a specific order or sequence order. It is to be understood that such terms are interchangeable under appropriate circumstances such that the embodiments described herein are capable of operation in sequences other than those illustrated or otherwise described herein.

After introducing the technical terms related to the present application, the application scenarios and design ideas of the embodiments of the present application are briefly described below.

With the development of intelligent mobile communication equipment, in order to improve the front screen occupation ratio of terminal equipment, flexible screens usually adopt to buckle the communication panel. In market promotion, the mobile phone with the folding screen is popular with consumers. With the deep application of 4G, the requirement of consumers on the signal transmission capability of products is increased. The existing PI material folding screen can not meet the transmission requirement of the RF signal. High frequency materials must be used to improve the performance of the product. The transmission loss is too large to meet the signal transmission requirement when the traditional PI material is used.

In the related art, the FPC mostly uses high frequency materials such as LCP, MPI, etc. as a base material to realize signal transmission.

However, the minimum thickness of these high-frequency materials is mostly 14um, and the overall thickness is too large when using multilayer wiring, and the bending performance is not good.

Therefore, the embodiment of the application provides a soft board structure.

The first embodiment is as follows:

with reference to fig. 1 and fig. 2, the flexible printed circuit board structure provided in the embodiment of the present application includes: developments kink 1 and static kink 2, the one end and the static kink 2 of developments kink 1 are connected, and developments kink 1 includes:

an RF routing area 3, wherein a first medium layer 6 is arranged in the RF routing area 3;

a non-RF wiring area 4, wherein a second dielectric layer 7 is arranged in the non-RF wiring area;

the material corresponding to the first dielectric layer 6 comprises a high frequency substrate, and the material corresponding to the second dielectric layer 7 comprises a conventional substrate.

In this way, the dynamic bending part 1 is partitioned, and the wires are partitioned according to different signal transmission performance requirements. Therefore, the thickness of the bending area can be reduced, the bending performance is improved, and the problem of crosstalk of the routing in the same area can be solved by the partition routing.

As shown in fig. 3, in the present embodiment, the RF routing area 3 includes: the first copper-clad plate and cover rete. The covering film layer 5 covers the outer wall of the first copper-clad plate. Wherein, first copper-clad plate includes: a first dielectric layer 6 and a first conductive layer 8. A first dielectric layer 6 is provided on the first conductive layer 8.

Since the material corresponding to the first dielectric layer 6 includes the high-frequency substrate, the signal transmission performance requirement required by the radio frequency circuit wiring can be met in the RF wiring area. Meanwhile, the RF wiring area 3 is simple in structure and composition, and can be reduced in thickness, so that the bending performance is improved.

As shown in fig. 4, in the present embodiment, the non-RF wiring area 4 is disposed on one side of the RF wiring area 3, and the non-RF wiring area 4 includes: a second copper-clad plate and a cover film layer 5. The second copper-clad plate comprises second to fourth conducting layers and a second dielectric layer 7; the second to fourth conductive layers include a second conductive layer 9, a third conductive layer 10, and a fourth conductive layer 11, which are sequentially arranged from bottom to top. A second dielectric layer 7 is provided between second conductive layer 9 and third conductive layer 10, and a second dielectric layer is also provided between third conductive layer 10 and fourth conductive layer 11. The covering film layer 5 is arranged on the outer wall of the second copper-clad plate.

The non-RF wiring area 4 is disposed on one side of the RF wiring area 3, and as a practical way, the RF wiring area 3 is disposed on the inner side, and the non-RF wiring area 4 is disposed on the outer side of the RF wiring area 3, so that the collision of the RF wiring area during use can be reduced, thereby reducing the loss. As another practicable manner, the positions of the RF routing area 3 and the non-RF routing area 4 may be adjusted according to actual use requirements, and the RF routing area 3 may be disposed on the left side or the right side of the non-RF routing area. And a second to a fourth conducting layers and a second medium layer 7 are arranged in the second copper-clad plate in the non-RF wiring area 4, so that the wiring with low signal transmission performance can be conveniently distributed.

The dynamic bending part 1 is partitioned by locally cutting off different base materials, a high-frequency base material is used in the RF wiring area 3, and a conventional base material is not used in the RF wiring area 4. This reduces the overall thickness of the dynamic bend 1. In addition, the requirement of routing in different areas can be met, and the problems of crosstalk and loss of routing in the same area are solved.

As shown in fig. 5, in the present embodiment, the static bending portion 2 includes: a third copper-clad plate and a covering film layer 5. The covering film layer 5 is arranged on the outer wall of the third copper-clad plate. The third copper-clad plate comprises first to fourth conducting layers and a dielectric layer, and the second conducting layer 9, the third conducting layer 10, the first conducting layer 8 and the fourth conducting layer 11 are sequentially arranged from bottom to top; the dielectric layers include a first dielectric layer 6 and a second dielectric layer 7.

The static bending part 2 with lower bending frequency has lower requirement on the bending performance, so a layered structure is adopted, the dielectric layers comprise a first dielectric layer 6 and a second dielectric layer 7, and a proper wiring area can be selected according to the signal transmission performance requirement.

In the static bending part 2, a high-frequency substrate and a conventional substrate are used in a mixed manner by adopting a multi-layer stacked structure, specifically, in this embodiment, a second conductive layer 9, a third conductive layer 10, a first conductive layer 8, and a fourth conductive layer 11 are sequentially arranged from bottom to top; a second dielectric layer 7 is provided between the second conductive layer 9 and the third conductive layer 10, a first dielectric layer 6 is provided between the third conductive layer 10 and the first conductive layer 8, and a second dielectric layer 7 is provided between the first conductive layer 8 and the fourth conductive layer 11.

The first medium layer 6 is arranged at the middle position, so that the damage caused by collision of external force is reduced in the using process, and meanwhile, the influence on the signal transmission performance is avoided.

Because the number of the conducting layers and the dielectric layers in the static bending part 2 is large, and the number of the conducting layers and the dielectric layers in the dynamic bending part 1 is small, the thickness of the static bending part 2 is larger than that of the dynamic bending part 1 as a whole. In this way, the bending performance of the dynamic bending portion 1 can be improved.

In the present embodiment, the dynamic bending portion 1 is one or more.

When the dynamic bending part 1 is one, two ends of the dynamic bending part 1 are respectively connected with the static bending part 2. The two static bending portions 2 are a first static bending portion and a second static bending portion, respectively.

When bending is required, taking the first static bending part as a static state as an example, taking the center of the dynamic bending part 1 as a bending point, an external force is applied to the second static bending part to make the second static bending part close to or the first static bending part. The dynamic bending part 1 is bent in the process that the second static bending part is close to the first static bending part, so that the form of the soft board structure is changed, and the soft board structure can be switched between a flat laying state and a bending state.

Because the dynamic bending part 1 comprises the RF wiring area 3 and the non-RF wiring area 4, the wiring can be partitioned according to the signal transmission performance requirement, and the crosstalk problem of wiring in the same area is improved.

As a practical manner, the dynamic bending portion 1 is plural. Similarly, the two ends of the dynamic bending portion 1 are connected to the static bending portion 2. Similarly, the shape of the flexible printed circuit board body is changed by bending the dynamic bending part 1, and along with the increase of the number of the dynamic bending parts 1, the form of the flexible printed circuit board structure is more diversified to adapt to different requirements.

In the present embodiment, the first conductive layer 8, the second conductive layer 9, the third conductive layer 10, and the fourth conductive layer 11 are all formed with through holes (not shown), and copper layers are electroplated in the through holes to electrically connect the first conductive layer 8, the second conductive layer 9, the third conductive layer 10, and the fourth conductive layer 11. Based on the conductive performance of copper, after the copper layer is electroplated into the through hole, the conductive connection of the conductive layers can be realized.

In the present embodiment, the material of the first dielectric layer 6 includes at least one of LCP, MPI, PTFE, and PPS.

LCP (Liquid Crystal Polymer) is a Liquid Crystal Polymer, and has weather resistance, radiation resistance, and excellent electrical insulation properties. The high-frequency high-speed flexible board can be realized on the premise of ensuring high reliability. However, the shrinkage of LCP is too high, which results in high production difficulty and high production cost.

MPI (modified PI), also known as heterogeneous PI, has material properties including dielectric constant, moisture resistance and transmission loss between those of conventional substrates (e.g., PI) and high frequency substrates (e.g., LCP), but has a lower material shrinkage than LCP. Compared with LCP, MPI has lower difficulty in forming MPI base material and lower production cost.

PTFE (Polytetrafluoroethylene) is Polytetrafluoroethylene, is high temperature resistant and corrosion resistant, has excellent electrical insulation, is not easily interfered by high-frequency electric waves, and can provide ultrahigh frequency and high-speed performance for data centers, signal transmitting towers and personal electronic equipment.

PPS (Polyphenylene sulfide) is Polyphenylene sulfide, and has the advantages of high mechanical strength, high temperature resistance, good thermal stability and excellent insulating property.

In this embodiment, different materials may be selected as the material corresponding to the first dielectric layer 6 according to different signal transmission performance requirements, production costs, application environments, and other factors. Through the material with excellent electrical insulation, the external signal interference can be reduced to meet the signal transmission performance requirement.

In this embodiment, the material corresponding to the second dielectric layer 7 includes PI.

PI (polyimide film) is a polyimide film and has excellent high-low temperature resistance and electrical insulation.

In the actual production process, the first step is as follows: and baking the base material to dry moisture in the dielectric layers (including the first dielectric layer 6 and the second dielectric layer 7) so as to avoid the influence of expansion and shrinkage, layering and the like on subsequent production. And secondly, drilling through holes in the first to fourth conducting layers and the dielectric layer. The third step: the second conducting layer 9, the second dielectric layer 7, the third conducting layer 10, the first dielectric layer 6, the first conducting layer 8, the second dielectric layer 7 and the fourth conducting layer 11 are sequentially stacked from bottom to top, and the first conducting layer to the fourth conducting layer can be conductively connected due to the fact that copper layers are plated in the through holes through an electroplating process. The fourth step: and covering the covering film layer 5 on the outer walls of the first copper-clad plate, the second copper-clad plate and the third copper-clad plate. And finally, forming a soft board structure through high-temperature and high-heat pressing.

Another embodiment of the present application provides a communication device, including the above flexible printed circuit board structure.

It can be understood that the flexible board structure provided by the embodiment of the present application can be used in the manufacture of communication screens, and in particular, can be used in products such as mobile phones, notebook computers, PADs, digital cameras, and the like.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the system and the apparatus described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In addition, in the description of the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. A flexible board structure comprising: dynamic kink and static kink, the one end of dynamic kink with static kink is connected, its characterized in that, the dynamic kink includes:

the RF wiring area is internally provided with a first dielectric layer;

the non-RF wiring area is internally provided with a second dielectric layer;

the material corresponding to the first dielectric layer comprises a high-frequency substrate, and the material corresponding to the second dielectric layer comprises a conventional substrate.

2. The flexible board structure of claim 1, wherein the RF routing area comprises:

the first copper-clad plate comprises a first dielectric layer and a first conducting layer, wherein the first dielectric layer is arranged on the first conducting layer;

and the covering film layer is covered on the outer wall of the first copper-clad plate.

3. The flexible board structure of claim 2, wherein the non-RF routing area is disposed at one side of the RF routing area, the non-RF routing area comprising:

the second copper-clad plate comprises second to fourth conducting layers and a second dielectric layer; a third conducting layer and a second conducting layer are sequentially arranged above the fourth conducting layer; a second dielectric layer is arranged between the second conducting layer and the third conducting layer, and the second dielectric layer is arranged between the fourth conducting layer and the third conducting layer;

and the covering film layer covers the outer wall of the second copper-clad plate.

4. The flexible board structure according to claim 3, wherein the static bend comprises:

the second copper-clad plate comprises a first conductive layer, a second conductive layer, a third conductive layer, a first conductive layer and a fourth conductive layer, wherein the first conductive layer, the second conductive layer and the third conductive layer are sequentially arranged from bottom to top; the dielectric layers comprise the first dielectric layer and the second dielectric layer;

the covering film layer is arranged on the outer wall of the third copper-clad plate.

5. The flexible printed circuit board structure of claim 4, wherein the first dielectric layer is disposed between the third conductive layer and the first conductive layer;

the first dielectric layer is arranged between the second conducting layer and the third conducting layer, and between the first conducting layer and the fourth conducting layer.

6. The flexible board structure according to claim 1, wherein the dynamic bending portion is one or more.

7. The flexible board structure of claim 1, wherein the first through fourth conductive layers are each provided with a through hole, and the through holes are plated with copper layers to electrically connect the first through fourth conductive layers.

8. The flexible board structure according to claim 1, wherein the material corresponding to the first dielectric layer comprises at least one of LCP, MPI, PTFE, PPS.

9. The flexible board structure of claim 1, wherein the material corresponding to the second dielectric layer comprises PI.

10. A communication device comprising a flexible board structure according to any one of claims 1 to 9.

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