CN113692110A

CN113692110A - Flexible circuit board and mobile terminal

Info

Publication number: CN113692110A
Application number: CN202110913742.3A
Authority: CN
Inventors: 庄毅强
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2021-08-10
Filing date: 2021-08-10
Publication date: 2021-11-23

Abstract

The application discloses flexible line way board and mobile terminal. The flexible circuit board is provided with a bending area and comprises a first bonding layer, a substrate and a covering film. The first bonding layer located in the bending area is formed with a first hollow-out area. The base material is connected with the first bonding layer and comprises a dielectric layer and a conductive layer connected with the dielectric layer, and a second hollow-out area is formed in the conductive layer positioned in the bending area; the cover film is connected with the substrate. Therefore, the second hollow area can avoid the influence of transmission loss caused by the fact that radio frequency signals enter air and the like when the radio frequency signals are transmitted in the first hollow area, and meanwhile, the transmission loss caused by the fact that the first hollow area is different in height when the radio frequency signals are bent can be eliminated, so that the transmission quality of the flexible circuit board is improved, and user experience is improved.

Description

Flexible circuit board and mobile terminal

Technical Field

The application relates to the technical field of flexible circuit boards, in particular to a flexible circuit board and a mobile terminal.

Background

The Flexible Printed Circuit (FPC) has the characteristics of light weight, thin thickness, good bending property and the like, and can be widely applied to mobile terminals, consumer electronics, automotive electronics, industrial control, medical treatment, aerospace military and the like. With the development of mobile terminals, the demand for flexible circuit boards in foldable mobile phones is higher, and in the prior art, the impedance of radio frequency signals of a multilayer flexible circuit board is easily mismatched, so that transmission loss is reduced, and transmission of the radio frequency signals is affected.

Disclosure of Invention

The embodiment of the application provides a flexible circuit board and a mobile terminal.

The flexible circuit board that this application embodiment provided has the bending region, flexible circuit board includes first adhesive layer, substrate and cover film. The first bonding layer located in the bending area is formed with a first hollow-out area. The base material is connected with the first bonding layer and comprises a dielectric layer and a conductive layer connected with the dielectric layer, and a second hollow-out area is formed in the conductive layer positioned in the bending area; the cover film is connected with the substrate.

The mobile terminal provided by the embodiment of the application comprises a first part, a second part and the flexible circuit board. The second portion is rotatably disposed with the first portion. The flexible wiring board is disposed at a junction of the first portion and the second portion.

Therefore, the second hollow area can avoid the influence of transmission loss caused by the fact that radio frequency signals enter air and the like when the radio frequency signals are transmitted in the first hollow area, and meanwhile, the transmission loss caused by the fact that the first hollow area is different in height when the radio frequency signals are bent can be eliminated, so that the transmission quality of the flexible circuit board is improved, and user experience is improved.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic cross-sectional view of a flexible wiring board of an embodiment of the present application;

fig. 2 is a schematic structural diagram of a mobile terminal according to an embodiment of the present application;

FIG. 3 is a schematic partial cross-sectional view of a flexible wiring board of an embodiment of the present application;

FIG. 4 is a schematic plan view of a first substrate according to an embodiment of the present application;

FIG. 5 is a schematic plan view of a second substrate according to an embodiment of the present application;

fig. 6 is a schematic plan view of a third substrate according to an embodiment of the present application.

Description of the main element symbols:

the flexible printed circuit board comprises a flexible printed circuit board 100, a first adhesive layer 10, a bending region 101, a reinforcing region 102, a first hollowed-out region 11, a substrate 20, a first substrate 201, a second substrate 202, a third substrate 203, a conductive layer 21, a dielectric layer 22, a second hollowed-out region 23, a radio frequency line 24, a ground line 25, a cover film 30, a first cover film 301, a second cover film 302, a third cover film 303, a protective layer 31, a second adhesive layer 32, an electromagnetic shielding film 40, a third adhesive layer 41, a metal layer 42, an insulating layer 43, a mobile terminal 1000, a first portion 200 and a second portion 300.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative and are only for the purpose of explaining the present application and are not to be construed as limiting the present application.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

The following disclosure provides many different embodiments or examples for implementing different features of the application. In order to simplify the disclosure of the present application, specific example components and arrangements are described below. Of course, they are merely examples and are not intended to limit the present application.

Referring to fig. 1, a flexible printed circuit 100 provided in the present embodiment has a bending region 101, and the flexible printed circuit 100 includes a first adhesive layer 10, a substrate 20, and a cover film 30. The first adhesive layer 10 located in the bending region 101 is formed with a first hollow area 11. The substrate 20 is connected with the first bonding layer 10, the substrate 20 comprises a dielectric layer 22 and a conductive layer 21 connected with the dielectric layer 22, and a second hollow area 23 is formed on the conductive layer 21 in the bending area 101; the cover film 30 is attached to the substrate 20.

So, the setting of second fretwork area 23 can get rid of radio frequency signal and get into when first fretwork area 11 transmits and bring the great influence of dielectric loss change such as air, still can avoid the first fretwork area 11 of flexible line way board 100 to lead to the fact the fluctuation of dielectric loss because of the difference in height when buckling the process simultaneously to promote flexible line way board 100's transmission quality, promote user experience.

Specifically, the flexible wiring board 100 may include a plurality of substrates 20 and cover films 30. In one example, the flexible circuit board 100 may include three substrates 20, namely a first substrate 201, a second substrate 202, and a third substrate 203, stacked at intervals, wherein each of the first substrate 201, the second substrate 202, and the third substrate 203 includes a dielectric layer 22 and a conductive layer 21 connected to the dielectric layer 22.

The conductive layer 21 can be made of a flexible copper foil substrate, the outer layer of the copper foil substrate is covered with a copper foil, the copper foil can be rolled copper, the rolled copper is made by repeatedly rolling the copper plate for multiple times, and crystals of the rolled copper are flaky. The dielectric layer 22 may be made of one of Polyimide (PI), Modified Polyimide (MPI), Liquid Crystal Polymer (LCP) and Polytetrafluoroethylene (PTFE), and the material of the dielectric layer 22 may be selected according to the requirements of the dielectric layer 22, such as flexibility, heat resistance, dimensional stability, price, and the like. The conductive layer 21 in the bending region 101 has a second hollow area 23, that is, the dielectric layer 22 is hollowed out by copper in the bending region 101, and the substrate 21 and the cover film 30 can be bonded by an acrylic or epoxy adhesive.

The conductive layer 21 and the dielectric layer 22 may be connected by plating, coating, or pressing. In some embodiments, the conductive layer 21 and the dielectric layer 22 may be laminated after being connected by glue. The thickness of the conductive layer 21 may be 9-12um and the thickness of the dielectric layer 22 may be 12-25um along the extending direction perpendicular to the flexible printed circuit board 100.

In the above example, the flexible wiring board 100 further includes three cover films 30, i.e., a first cover film 301, a second cover film 302, and a third cover film 303, which are stacked at intervals. More specifically, the first cover film 301 is connected to the first substrate 201, and the first cover film 301 is disposed above the first substrate 201. The second cover film 302 is connected to the second substrate 202, and the second cover film 302 is disposed below the second substrate 202; the third cover film 303 is connected to the third substrate 203, and the third cover film 303 is disposed above the third substrate 203. The first adhesive layer 10 is provided between the first substrate 201 and the second substrate 202, and the first adhesive layer 10 is provided between the second substrate 202 and the third substrate 203. The cover film 30 can protect the substrate 20, isolate the substrate 20 from dust, moisture and the like, and prolong the service life of the flexible circuit board 100.

The first adhesive layer 10 mainly functions as an adhesive and can bond two substrates 20. The first adhesive layer 10 may be made of acrylic or epoxy. More specifically, an acrylic adhesive has excellent heat resistance and high adhesive strength, and an epoxy adhesive has a lower heat resistance than acrylic adhesives, but all other properties are well balanced. The first adhesive layer 10 located in the bending region 101 is formed with a first hollowed-out area 11, that is, an adhesive such as acrylic or epoxy resin, etc. located in the bending region 101 of the first adhesive layer 10 is hollowed out.

It should be noted that when the flexible circuit board 100 is bent, the bending region 101 of the flexible circuit board 100 is bent. The first adhesive layer 10 in the bending region 101 is formed with the first hollow area 11, so that the flexible circuit board 100 in the bending region 101 forms a layer, and the flexible circuit board 100 can have a good bending life. Thus, when the flexible printed circuit 100 is bent, the flexible printed circuit 100 located in the bending region 101 is softer due to the arrangement of the first hollow-out region 11, and the hardness of the flexible printed circuit 100 located in the bending region 101 is reduced, so that the bending life of the flexible printed circuit 100 can be prolonged, and the life of the flexible printed circuit in a dynamic bending scene can be longer than 20 ten thousand times.

When the second hollow area 23 is not formed in the conductive layer 21 located in the bending region 101, the rf signal is transmitted in the flexible circuit board 100, and the transmission loss of the rf signal is affected by the first hollow area 11 and the dielectric layer 22 by using the conductive layers 21 of the first substrate 201, the second substrate 202, and the third substrate 203 as reference layers. Because the first bonding layer 10 located in the bending region 101 is formed with the first hollow-out region 11, media such as air can enter the first hollow-out region 11, so that transmission loss of radio frequency signals of the flexible circuit board 100 fluctuates, and stable transmission of the radio frequency signals is not facilitated, and the arrangement of the first hollow-out region 11 can cause inconsistency of the thickness of the flexible circuit board 100 in the bending process, so that the heights of the dielectric layers 22 with different heights, through which the radio frequency signals pass, can cause loss fluctuation of signal transmission.

Thus, after the second hollow-out area 23 is formed on the conductive layer 21 in the bending area 101, the radio frequency signal does not use the conductive layer 21 of the first substrate 201, the second substrate 202 and the third substrate 203 as a reference layer, the second hollow-out area 23 can avoid the influence of transmission loss caused by the entry of air and the like during the transmission of the radio frequency signal in the first hollow-out area 11, and can also eliminate the transmission loss caused by the difference in height during the bending process of the first hollow-out area 11, thereby improving the transmission quality of the flexible circuit board 100 and improving the user experience.

It is understood that in certain embodiments, the flexible wiring board 100 may include a plurality of substrates 20 and cover films 30, and illustratively, the flexible wiring board 100 may include two substrates 20 and two cover films 30; the flexible wiring board 100 may further include four substrates 20 and four cover films 30; or the flexible circuit board 100 may further include five base materials 20 and five cover films 30, etc., and the number of the base materials 20 and the cover films 30 of the flexible circuit board 100 is not limited herein. It should be noted that the number of substrates 20 is the same as the number of cover films 30, so that the cover films 30 protect each substrate 20.

It is to be noted that the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the embodiments of the present application, unless otherwise explicitly specified or limited, the "over" or "under" of a first feature may include the first and second features being in direct contact, and may also include the first and second features not being in direct contact but being in contact with each other through another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

Referring to fig. 2, a mobile terminal 1000 according to an embodiment of the present disclosure includes a first portion 200, a second portion 300, and the flexible circuit board 100. The second part 300 is rotatably arranged with the first part 200. The flexible wiring board 100 is disposed at the junction of the first portion 200 and the second portion 300.

When the second portion 300 of the mobile terminal 1000 rotates, the bending region 101 of the flexible printed circuit board 100 may also be not easily damaged by bending, and when the flexible printed circuit board 100 bends, the flexible printed circuit board 100 located in the bending region 101 may be more flexible due to the arrangement of the first hollow-out region 11 of the first adhesive layer 10 located in the bending region 101, so that the bending life of the mobile terminal 1000 may be prolonged. In addition, the second hollow area 23 may also improve the signal transmission capability of the mobile terminal 1000.

In particular, the mobile terminal 1000 includes, but is not limited to, smart phones, notebooks, tablets, and wearable devices. Wherein the second portion 300 is rotatable, when the flexible circuit board 100 is disposed at the connection position of the first portion 200 and the second portion 300, the bending region 101 of the flexible circuit board 100 can be disposed corresponding to the second portion 300,

referring to fig. 1, in some embodiments, at least one rf line 24 and a ground line 25 spaced apart from the rf line 24 are formed on the conductive layer 21 of the bending region 101, and a second hollow area 23 is formed between the rf line 24 and the spaced ground line 25. In this manner, the rf line 24 may be used for signal transmission of the flexible wiring board 100.

Specifically, in one example, the flexible printed circuit board 100 may include three substrates 20, namely a first substrate 201, a second substrate 202, and a third substrate 203, stacked at intervals, wherein each of the first substrate 201, the second substrate 202, and the third substrate 203 includes a dielectric layer 22 and a conductive layer 21 connected to the dielectric layer 22.

The conductive layers 21 on the first substrate 201 in the bending region 101 are all the second hollow regions 23; the conductive layer 21 of the second substrate 202 located in the bending region 101 is provided with a grounding wire 25, and the regions of the conductive layer 21 of the second substrate 202 except the grounding wire 25 are second hollow regions 23; the radio frequency line 24 and the ground line 25 are both disposed on the conductive layer 21 of the third substrate 203 located in the bending region 101, and the regions of the conductive layer 21 of the third substrate 203 except the regions where the ground line 25 and the radio frequency line 24 are both the second hollow region 23. Since the hollow-out area is formed on the conductive layer 21, the rf line 24 does not use the conductive layer 21 of the first substrate 201, the second substrate 202, and the third substrate 203 as a reference layer, and the second hollow-out area 23 is disposed to avoid transmission loss influence caused by air and the like when the rf signal is transmitted in the first hollow-out area 11.

In some embodiments, the rf line 24 may be disposed on the first substrate 201, the second substrate 202, or the third substrate 203; the conductive layer 21 of the first substrate 201 and/or the second substrate 202 may have the grounding line 25 disposed thereon, or the conductive layer 21 of the first substrate 201 and the second substrate 202 may not have the grounding line 25 disposed thereon. When the same conductive layer 21 in the bending region 101 is provided with the rf line 24 and the ground line 25, a second hollow area 23 is formed between the rf line 24 and the ground line 25; when the conductive layer 21 in the bending region 101 is not provided with the ground line 25 and the rf line 24, the conductive layer 21 is entirely the second hollow area 23; when only the rf line 24 or the ground line 25 is disposed on one conductive layer 21 of the bending region 101, the regions of the conductive layer 21 except the rf line 24 or the connection line 25 are the second hollow regions 23.

Referring to fig. 1, in some embodiments, the number of the conductive layers 21 is multiple, the conductive layers 21 are stacked, at least one conductive layer 21 forms a ground line 25, one conductive layer 21 forms a radio frequency line 24, and a second hollow area 23 is formed between the same ground line 25 and the radio frequency line 24.

Thus, the second hollow-out region 23 can also eliminate the transmission loss caused by the different heights of the first hollow-out region 11 between the conductive layers 21 during the bending process, thereby improving the transmission quality of the flexible circuit board 100 and improving the user experience.

In one example, the number of the conductive layers 21 may be three, that is, the first conductive layer 21, the second conductive layer 21, and the third conductive layer 21. The first conductive layers 21 in the bending region 101 are all the second hollow regions 23, the second conductive layers 21 in the bending region 101 are provided with two ground lines 25, and the third conductive layers 21 in the bending region 101 are provided with two rf lines 24 and two ground lines 25 spaced from the two rf lines 24.

Referring to fig. 1, in some embodiments, the distance B between the rf line 24 and the adjacent ground line 25 along the extending direction of the flexible circuit board 100 is greater than or equal to 0.2 mm.

In this way, the misalignment between the plurality of conductive layers 21 and the cover film 30 in the flexible wiring board 100 can be avoided, thereby affecting the transmission of signal transmission. In the extending direction of the flexible printed circuit board 100, the distance B between the radio frequency line 24 and the adjacent ground line 25 may be 0.2mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, 0.3mm, 0.32mm, 0.34mm, 0.36mm, etc.

In one example, the flexible printed circuit board 100 includes three substrates 20, namely a first substrate 201, a second substrate 202, and a third substrate 203, which are stacked at intervals, wherein each of the first substrate 201, the second substrate 202, and the third substrate 203 includes a dielectric layer 22 and a conductive layer 21 connected to the dielectric layer 22, and the flexible printed circuit board 100 further includes an electromagnetic shielding film 40, and the electromagnetic shielding film 40 is disposed on one side of the cover film 30 facing away from the substrate 20.

In this case, two rf lines 24 may be disposed on the conductive layer 21 of the third substrate 203 in the bending region 101, two ground lines 25 disposed at intervals are disposed on the conductive layers 21 of the second substrate 202 and the third substrate 203 in the bending region 101, and a distance range between the rf line 24 and the adjacent ground line 25 along the extending direction of the flexible printed circuit board 100 is greater than or equal to 0.2 mm.

Referring to fig. 1, in some embodiments, along the extending direction of the flexible circuit board 100, the number of the rf lines 24 is multiple, the multiple rf lines 24 are disposed at intervals, a second hollow area 23 is formed between two adjacent rf lines 24, and a range of a distance a between two adjacent rf lines 24 is greater than or equal to 0.3 mm.

Therefore, the crosstalk between two adjacent radio frequency lines 24 can be reduced, so that the transmission loss caused by the crosstalk is avoided, and the performance of the flexible circuit board 100 is improved. In the case that the range of the distance a between two adjacent radio frequency lines 24 is less than 0.3mm, there is crosstalk of signals when the two adjacent radio frequency lines 24 transmit signals, thereby affecting the stability of signal transmission. The distance a between two adjacent radio frequency lines 24 may be 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, etc.

Referring to fig. 1, in some embodiments, the cover film 30 includes a protective layer 31 and a second adhesive layer 32 connected to the protective layer 31, and the second adhesive layer 32 is connected to the conductive layer 21.

Therefore, the cover film 30 can protect the substrate 20, isolate the conductive layer 21 from the outside, and prevent factors such as dust or moisture from affecting the conductive layer 21, so as to prolong the service life of the flexible circuit board 100.

Specifically, the material of the protective layer 31 may be the same as that of the dielectric layer 22, and for example, the protective layer 31 may be made of Polyimide (PI), Modified Polyimide (MPI), Liquid Crystal Polymer (LCP), or Polytetrafluoroethylene (PTFE). The second adhesive layer 32 mainly serves to bond the protective layer 31 and the conductive layer 21. The material of second adhesive layer 32 may be the same as that of first adhesive layer 10, and second adhesive layer 32 may be made of acrylic or epoxy.

In some embodiments, when all the conductive layers 21 of a certain substrate 21 in the flexible printed circuit board 100 are the second hollow areas 23, the adhesive filled in the second adhesive layer 32 connected to the conductive layers 21 may be hollowed, so as to further improve the bending life of the flexible printed circuit board 100.

In one example, the flexible printed circuit board 100 includes two substrates 20, namely a first substrate 201 and a second substrate 202, stacked at an interval, wherein each of the first substrate 201, the second substrate 202 and the third substrate 203 includes a dielectric layer 22 and a conductive layer 21 connected to the dielectric layer 22; the flexible wiring board 100 further includes two cover films 30 stacked at intervals, that is, a first cover film 301 and a second cover film 302, and each of the first cover film 301 and the second cover film 302 includes a protective layer 31 and a second adhesive layer 32 connected to the protective layer 31. The first adhesive layer 10 is provided between the first substrate 201 and the second substrate 202, and the first adhesive layer 10 is provided between the second substrate 202 and the third substrate 203. The first adhesive layer 10 located in the bending region 101 is formed with a first hollow area 11.

In this example, the second adhesive layer 32 of the first coverlay film 301 is connected to the conductive layer 21 of the first substrate 201, and the second adhesive layer 32 of the second coverlay film 302 is connected to the conductive layer 21 of the second substrate 202. The conductive layers 21 on the first substrate 201 in the bending region 101 are all the second hollow areas 23, and the adhesive filled in the second adhesive layer 32 of the second cover film 302 is hollowed, so that the second adhesive layer 32 of the second cover film 302 is hollowed, and the flexible circuit board 100 is more flexible, thereby prolonging the bending life of the flexible circuit board 100.

Referring to fig. 1 and fig. 3 to fig. 6, in some embodiments, reinforcing regions 102 are disposed on two opposite sides of the bending region 101 along the extending direction of the flexible circuit board 100.

In this way, the reinforcing region 102 can reinforce the mechanical strength of the flexible circuit board 100, and can also facilitate the installation of other parts.

In one embodiment, the flexible printed circuit 100 includes two bending regions 101 disposed at an interval, and the flexible printed circuit 100 further includes three bending regions 101, wherein reinforcing regions 102 are disposed on two sides of each bending region 101, so as to reinforce the mechanical strength of the non-bending portion of the flexible printed circuit 100. The first adhesive layer 10 in the reinforcing region 102 does not form a hollow structure, so that the strength of the flexible printed circuit 100 can be better increased, and the service life of the flexible printed circuit 100 can be prolonged.

In some embodiments, the flexible circuit board 100 further has a hard region disposed on a side of the reinforcing region 102 facing away from the bending region 101, and the hard region can also reinforce the strength of the flexible circuit board 100.

In some embodiments, the reinforcing region 102 is provided with blind holes and/or through holes, and when the flexible circuit board 100 includes a plurality of substrates 20, the blind holes and/or through holes can connect the conductive layers 21 in the plurality of substrates 20, thereby facilitating the conduction of signals.

Referring to fig. 1, in some embodiments, the flexible printed circuit 100 further includes an electromagnetic shielding film 40 disposed on a side of the cover film 30 away from the substrate 20, where the electromagnetic shielding film 40 includes a third adhesive layer 41 and a metal layer 42 connected to the third adhesive layer 41, the third adhesive layer 41 is connected to the cover film 30, and the metal layer 42 is electrically connected to the conductive layer 21.

Thus, the electromagnetic shielding film 40 can shield electromagnetic interference, and further reduce the influence of the outside on the transmission signal of the radio frequency line 24, thereby ensuring that the flexible circuit board 100 keeps a high-frequency and high-speed transmission rate in the bending process.

In one example, the flexible printed circuit board 100 includes three substrates 20, namely a first substrate 201, a second substrate 202, and a third substrate 203, stacked at intervals, wherein each of the first substrate 201, the second substrate 202, and the third substrate 203 includes a dielectric layer 22 and a conductive layer 21 connected to the dielectric layer 22.

The flexible wiring board 100 further includes three cover films 30, namely, a first cover film 301, a second cover film 302, and a third cover film 303, which are stacked at intervals. More specifically, a first cover film 301 is connected to the first substrate 201, a second cover film 302 is connected to the second substrate 202, and a third cover film 303 is connected to the third substrate 203. The third adhesive layer 41 of the electro-magnetic shielding film 40 is connected to the protective layer 31 of the third coverlay film 303, and the third adhesive layer 41 of the electro-magnetic shielding film 40 is connected to the metal layer 42. The metal layer 42 may be made of copper alloy material, the material of the third adhesive layer 41 may be the same as the first adhesive layer 10, and the third adhesive layer may be made of acrylic or epoxy resin.

In this case, the conductive layer 21 of the third substrate 203 in the bending region 101 is provided with the ground line 25 and the radio frequency line 24, the radio frequency line 24 may use the metal layer 42 of the electromagnetic shielding film 40 as a reference layer, and since the electromagnetic shielding film 40 needs to be grounded, the radio frequency line 24 may flow back, so that a large amount of electromagnetic interference may be accumulated in the electromagnetic shielding film 40, and therefore the ground line 25 provided on the conductive layer 21 of the third substrate 203 in the bending region 101 may discharge the interference, thereby ensuring the stability of signal transmission.

Referring to fig. 1 again, in some embodiments, the electromagnetic shielding film 40 further includes an insulating layer 43 connected to the metal layer 42, and the insulating layer 43 is located on a side of the metal layer 42 facing away from the third adhesive layer 41. Therefore, the insulating layer 43 can protect the metal layer 42 of the electromagnetic shielding film 40 from being oxidized and can also play an insulating role, otherwise, the outer surface of the electromagnetic shielding film 40 is in a conductive state, and potential safety hazards exist in the using process.

In the description herein, references to the description of the terms "one embodiment," "certain embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that: numerous changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. A flexible wiring board having a bend region, the flexible wiring board comprising:

the first bonding layer is positioned in the bending area, and a first hollow-out area is formed in the first bonding layer;

the base material is connected with the first bonding layer and comprises a dielectric layer and a conductive layer connected with the dielectric layer, and a second hollow-out area is formed in the conductive layer positioned in the bending area; and

a cover film attached to the substrate.

2. The flexible circuit board of claim 1, wherein the conductive layer in the bending region is formed with at least one rf line and a ground line spaced apart from the rf line, and the second hollow area is formed between the rf line and the spaced ground line.

3. The flexible circuit board of claim 2, wherein the number of the conductive layers is multiple, a plurality of the conductive layers are stacked, at least one of the conductive layers is formed with the ground line, one of the conductive layers is formed with the rf line, and the second hollow area is formed between the ground line and the rf line on the same layer.

4. The flexible wiring board of claim 3, wherein a range of a spacing between the radio frequency line and the adjacent ground line along an extending direction of the flexible wiring board is greater than or equal to 0.2 mm.

5. The flexible printed circuit according to claim 2, wherein along an extending direction of the flexible printed circuit, the number of the radio frequency lines is plural, the plural radio frequency lines are arranged at intervals, the second hollow area is formed between two adjacent radio frequency lines, and a distance range between two adjacent radio frequency lines is greater than or equal to 0.3 mm.

6. The flexible wiring board of claim 1, wherein the cover film comprises a protective layer and a second adhesive layer connected to the protective layer, the second adhesive layer being connected to the conductive layer.

7. The flexible wiring board of claim 1, wherein reinforcing regions are disposed on opposite sides of the bending region along an extending direction of the flexible wiring board.

8. The flexible wiring board of claim 1, further comprising an electromagnetic shielding film disposed on a side of the cover film facing away from the substrate, the electromagnetic shielding film comprising a third adhesive layer and a metal layer connected to the third adhesive layer, the third adhesive layer being connected to the cover film, the metal layer being electrically connected to the conductive layer.

9. The flexible wiring board of claim 8, wherein the electromagnetic shielding film further comprises an insulating layer connected to the metal layer, the insulating layer being located on a side of the metal layer facing away from the third adhesive layer.

10. A mobile terminal, comprising:

a first portion;

a second part rotatably disposed with the first part;

the flexible wiring board of any of claims 1-9, disposed at a junction of the first portion and the second portion.