CN115023025B - Flexible circuit board and electronic equipment - Google Patents

Abstract

The embodiment of the application provides a flexible circuit board and electronic equipment. The flexible circuit board is provided with a preset bending area; the flexible circuit board includes: the flexible substrate comprises a flexible substrate, a conducting layer and a first covering layer, wherein the conducting layer is arranged on the surface of the flexible substrate, and the first covering layer is arranged on the surface, far away from the flexible substrate, of the conducting layer; the position of the first covering layer corresponding to the preset bending area is provided with at least one first groove and at least one second groove; the first open slot and the second open slot are arranged through the first covering layer; the first open slot is provided with a first covering layer with resilience lower than that of the first covering layer; the flexible substrate in the preset bending area is provided with a third open slot, and the third open slot and the connecting line of the conducting layer are arranged in a staggered mode. The flexible circuit board and the electronic equipment can solve the problem that in the prior art, the resilience force generated by bending of the FPC can generate continuous stress on the connection position of the FPC and the PCB.

Description

Flexible circuit board and electronic equipment

Technical Field

The embodiment of the application relates to the technical field of electronic circuits, in particular to a flexible circuit board and electronic equipment.

Background

A Flexible Printed Circuit board (FPC), also called a Flexible Circuit board or a Flexible Printed Circuit board, is a Flexible Printed Circuit board with high reliability, which is made of a series of film materials such as polyimide or polyester film as a base material. Because of the characteristics of lightness, thinness, free bending, winding and folding, the film is more and more applied to the fields or products of mobile communication, notebook computers, computers and the like.

One of the functions of the FPC is to connect a different Printed Circuit Board (PCB) in the electronic apparatus, or to connect other devices to the PCB. In order to reduce the space occupied by the circuit board assembly, it is generally necessary to bend the FPC by an external driving force. When the FPC is bent, internal stress is generated in the bending region of the FPC, and a repulsive force is generated by bending. This spring back force can cause continuous stress on the connection location of the FPC to the PCB, thereby increasing the risk of failure.

Disclosure of Invention

The embodiment of the application provides a flexible circuit board and electronic equipment, can solve among the prior art FPC because the resilience force of buckling the production can produce the problem of continuous stress to FPC and PCB's hookup location.

A first aspect of the present application provides a flexible circuit board having a preset bending region; the flexible circuit board includes: the flexible substrate comprises a flexible substrate, a conducting layer and a first covering layer, wherein the conducting layer is arranged on the surface of the flexible substrate, and the first covering layer is arranged on the surface, far away from the flexible substrate, of the conducting layer; the position of the first covering layer corresponding to the preset bending area is provided with at least one first groove and at least one second groove; the first open groove and the second open groove penetrate through the first covering layer; the flexible substrate is provided with a first groove, the first groove is provided with a first covering layer, the resilience of the first covering layer is lower than that of the second covering layer, the first covering layer is used for covering a conducting layer in the first groove, the flexible substrate in the preset bending area is provided with a first groove, and the first groove is arranged in a staggered mode with a connecting line of the conducting layer.

The flexible circuit board provided by the embodiment of the application is characterized in that a first groove and a second groove corresponding to a connecting line of a conducting layer are formed in a position, corresponding to a preset bending area, of a first covering layer, the first groove and the second groove penetrate through the first covering layer, a second covering layer used for covering the connecting line of the conducting layer is arranged at the first groove, a third groove is further formed in a flexible substrate of the preset bending area, and the third groove and the connecting line of the conducting layer are arranged in a staggered mode. Can ensure the insulating protective action to the conducting layer like this, still do benefit to and improve the compliance that first overburden corresponds to the regional position of predetermineeing bending for FPC predetermine bending region and more easily bend the deformation, like this, after bending the processing, the regional resilience force of predetermineeing bending of flexible circuit board reduces relatively, can reduce or even avoid flexible circuit board predetermine bending region and take place the resilience phenomenon, do benefit to and keep predetermineeing the regional shape of bending.

In one possible implementation manner, the third slot is communicated with the second slot, so that flexibility of the position of the preset bending region can be further improved, resilience of the preset bending region is reduced, and meanwhile the risk of breaking the preset bending region can be reduced.

In one possible implementation manner, the third opening is disposed through the flexible substrate. In this way, flexibility at the position of the preset bending region can be further improved, and the resilience of the preset bending region can be reduced.

In one possible implementation manner, the first slot has a plurality, the second slot has a plurality, and at least part of the first slot and the second slot are distributed at intervals. Like this, both do benefit to the resilience force that reduces flexible circuit board's the regional of predetermineeing to bend, and can compromise the cracked performance demand of FPC anti-fracture.

In one possible implementation manner, the first slot and/or the second slot extend along a direction in which a connection line of the conductive layer of the flexible circuit board extends. Thus, the FPC can have more bendable positions and can be suitable for more scenes.

In one possible implementation, the thickness of the second cover layer is smaller than that of the first cover layer, so as to further reduce the flexibility of the preset bending area.

In one possible implementation, the modulus of the second cover layer is lower than the modulus of the first cover layer. Therefore, the flexibility of the preset bending region of the FPC is improved, and the resilience of the preset bending region of the FPC is reduced.

In one possible implementation, the modulus of the second cover layer is half of the modulus of the first cover layer. Therefore, the preset bending area of the FPC is softer and can be bent and deformed easily, and the rebound resilience of the preset bending area of the FPC is reduced.

In one possible implementation, the tensile strength of the second cover layer is lower than the tensile strength of the first cover layer. Therefore, the flexibility of the preset bending region of the FPC is improved, and the resilience of the preset bending region of the FPC is reduced.

In one possible implementation, the tensile strength of the second cover layer is half of the tensile strength of the first cover layer. Therefore, the preset bending area of the FPC is softer and can be bent and deformed easily, and the rebound resilience of the preset bending area of the FPC is reduced.

In one possible implementation manner, a part of the second cover layer is located in the first slot, and another part of the second cover layer extends out of the first slot and is connected with the surface of the first cover layer. Therefore, the connection reliability of the second covering layer and the first covering layer is improved, and the performance reliability of the second covering layer is ensured.

A second aspect of the embodiments of the present application provides an electronic device, including: the shell is provided with an accommodating space, and the flexible circuit board is arranged in the accommodating space.

Drawings

FIG. 1 is a schematic diagram of an electronic device;

FIG. 2 is an exploded view of an electronic device;

FIG. 3 is a schematic diagram of a circuit board assembly according to the related art;

FIG. 4 isbase:Sub>A cross-sectional view ofbase:Sub>A FPC along the direction A-A in FIG. 3 according to the related art;

FIG. 5 isbase:Sub>A schematic cross-sectional view of another FPC along the direction A-A in FIG. 3 according to the related art;

FIG. 6 is a schematic view illustrating bending of an FPC according to the related art;

fig. 7 is a schematic structural diagram of an FPC provided in an embodiment of the present application;

FIG. 8 is a schematic cross-sectional view of the FPC provided in the present application along the direction D-D in FIG. 7;

fig. 9a is a schematic structural diagram of a FPC according to another embodiment of the present application;

fig. 9b is a schematic structural diagram of a FPC according to another embodiment of the present application;

FIG. 10 is a schematic partial cross-sectional view of the FPC provided in the present application along the direction E-E in FIG. 9 a;

FIG. 11 is a schematic cross-sectional view of the FPC provided in the present application along the direction F-F in FIG. 9 a;

FIG. 12 is a schematic cross-sectional view of the FPC provided in the embodiment of the present application along the direction F-F in FIG. 9 a;

FIG. 13 is a schematic view of a second coverlay applied to an FPC according to an embodiment of the present disclosure;

fig. 14a is a first schematic structural diagram of an FPC according to yet another embodiment of the present application;

fig. 14b is a schematic structural diagram of a FPC according to yet another embodiment of the present application;

FIG. 15 is a schematic cross-sectional view of the FPC provided in the present application along the direction G-G in FIG. 14 a;

fig. 16 is a schematic cross-sectional view of an FPC according to another embodiment of the present application, taken along the direction G-G in fig. 14 a.

Description of reference numerals:

100-an electronic device;

10-a housing; 11-rear cover; 12-middle frame; 121-metal middle plate; 122-a frame;

20-a circuit board assembly;

21-FPC; 211-a flexible substrate; 2111-metallization of vias; 2112-third grooving; 213-a conductive layer; 215-first cover layer; 2151-first slot; 2152-second grooving; 217-a second cover layer;

23-PCB；

30-a display screen;

40-battery.

Detailed Description

The FPC provided by the embodiment of the application can be applied to electronic equipment. The electronic device may be a mobile terminal, a fixed terminal, or a foldable device having an FPC, such as a desktop computer, a notebook computer (laptop), a tablet computer (Table), an ultra-mobile personal computer (UMPC), a handheld computer, an intercom, a netbook, a POS machine, a Personal Digital Assistant (PDA), and the like.

The electronic device provided by the embodiment of the application may include, but is not limited to, a mobile or fixed terminal having a shooting function, such as a mobile phone, a tablet Computer, a notebook Computer, an Ultra-mobile Personal Computer (UMPC), a handheld Computer, an interphone, a netbook, a POS machine, a Personal Digital Assistant (PDA), a car recorder, and a security device. For convenience of description, the embodiments of the present application are described with reference to a mobile phone as an example.

Fig. 1 is a schematic perspective view of an electronic device; fig. 2 is an exploded view of an electronic device.

Referring to fig. 1 and fig. 2, an electronic device 100 provided in an embodiment of the present disclosure may include: a housing 10, the housing 10 may provide a structural framework for the electronic device 100. The housing 10 has an accommodating space in which the circuit board assembly 20 may be disposed. In addition, the accommodating space can also be used for accommodating the battery 40 or the speaker or the microphone or the receiver or the camera module of the electronic device 100.

Referring to fig. 1 and fig. 2, in some embodiments, when the electronic device 100 has a display function, the electronic device may further have a display 30, and the display 30 is mounted on the housing 10. The display screen 30 and the housing 10 together enclose a receiving space. The Display 30 may be an Organic Light-Emitting Diode (OLED) Display or a Liquid Crystal Display (LCD). The display 30 may be electrically connected to the circuit board assembly 20, and the display 30 may receive the control signal from the circuit board assembly 20 and perform corresponding display.

With continued reference to fig. 2, in some embodiments, the housing 10 may include a middle frame 12 and a rear cover 11 connected to each other, and assuming that the display screen 30 shown in fig. 2 is located in a direction of "front side" or "upper side" and the rear cover 11 is located in a direction of "rear side" or "lower side", in the example shown in fig. 2, the rear cover 11 is located relatively at the rear side of the middle frame 12, and the display screen 30 is located relatively at the front side of the middle frame 12. A circuit board assembly 20 may be disposed between the display screen 30 and the rear cover 11. In other embodiments, the housing 10 may be a one-piece or two-piece housing made of metal, plastic, or the like, and the implementation process may be the same as or similar to that of the embodiment of the present application.

In some embodiments, the rear cover 11 has a quadrilateral configuration, for example, the rear cover 11 may have a rounded rectangular configuration. The rear cover 11 may be a metal rear cover, a glass rear cover, a plastic rear cover, a ceramic rear cover, or the like. The material of the rear cover 11 is not limited in the embodiment of the present application.

With continued reference to fig. 2, in some embodiments, the middle frame 12 may include a metal middle plate 121 and a frame 122 connected to each other. The frame 122 is disposed around the edge of the metal middle plate 121, and the rear side of the frame 122 can be in sealing engagement with the edge of the rear cover 11. The frame 122 may include a top frame, a bottom frame, a left side frame, and a right side frame, which are enclosed to form a frame in a shape of a square ring. The frame 122 may be a metal frame or a ceramic frame. The metal middle plate 121 is located at the front side of the rear cover 11. The metal middle plate 121 may be an aluminum plate, an aluminum alloy plate, or a magnesium alloy plate. The metal middle plate 121 and the frame 122 may be clamped or welded or bonded or integrally formed.

In some embodiments, for example, the battery 40 is disposed in the accommodating space of the electronic device 100, the circuit board assembly 20 and the battery 40 may be disposed on the metal middle plate 121. The circuit board assembly 20 and the battery 40 may be disposed on a side of the middle metal plate 121 facing the rear cover 11, or the circuit board assembly 20 and the battery 40 may be disposed on a side of the middle metal plate 121 facing the display 30. The metal middle plate 121 may be opened, and at least some components on the circuit board assembly 20 may be disposed at the opening of the metal middle plate 121.

In some embodiments, the battery 40 may be coupled to the charge management module and the circuit board assembly 20 via a power management module that receives inputs from the battery 40 and the charge management module and provides power to the processor, internal memory, external memory, the display 30, and the communication module, among others. The power management module may also be used to monitor parameters such as the capacity of the battery 40, the number of cycles of the battery 40, the state of health (leakage, impedance, etc.) of the battery 40, etc. In other embodiments, the power management module may also be disposed in the processor of the circuit board assembly 30. In other embodiments, the power management module and the charging management module may be disposed in the same device.

Fig. 3 is a schematic structural diagram of a circuit board assembly in the related art. Referring to fig. 3, in some embodiments, the circuit board assembly 20 may include a PCB23 and an FPC21 a; among other things, one of the roles of the FPC21 a is to connect different PCBs 23 in the electronic apparatus 100, or to connect other devices to the PCBs 23.

Fig. 4 isbase:Sub>A schematic cross-sectional view ofbase:Sub>A related art FPC havingbase:Sub>A single-sided conductive layer along the directionbase:Sub>A-base:Sub>A in fig. 3; fig. 5 isbase:Sub>A schematic cross-sectional view of the related art FPC havingbase:Sub>A double-sided conductive layer along the directionbase:Sub>A-base:Sub>A in fig. 3. Referring to fig. 4 and 5, in some embodiments, the FPC21 a may include a flexible substrate 211a, a conductive layer 213a, and a first cover layer 215a. The conductive layer 213a is provided on the surface of the flexible substrate 211 a. The first cover layer 215a is disposed on the surface of the conductive layer 213a away from the flexible substrate 211 a.

In some embodiments, the flexible substrate 211a may be a single layer structure. The flexible substrate 211a may also be a multi-layer structure, for example, the flexible substrate 211a may include a plurality of dielectric layers disposed in a stacked manner.

In some embodiments, the flexible substrate 211a may be formed using a flexible base material. Flexible substrates include, but are not limited to, PET (polyester), PTFE (polytetrafluoroethylene), PI (Polyimide), PC (Polycarbonate), ABS (Acrylonitrile butadiene styrene plastic), LCP (Liquid Crystal Polymer), PEN (polyethylene terephthalate two-dimensional polyester resin ester), PP (Polypropylene), art paper, woven fabric (including stretch woven fabric and non-stretch woven fabric), and the like.

In some embodiments, at least one surface of the flexible substrate 211a is prepared with a conductive layer 213a having a set conductive pattern. The conductive layer 213a may be formed of copper foil, aluminum foil, gold foil, and conductive paste including, but not limited to, carbon-based conductive paste, metal particle conductive paste, inorganic conductive paste, liquid metal, and the like, which are known in the art. The carbon-based conductive paste at least comprises conductive carbon black or graphene, and the metal particle conductive paste at least comprises conductive metal particles, such as copper, silver, gold, silver-coated copper and the like. The liquid metal at least comprises low-melting-point metal with the melting point below 300 ℃, such as gallium-based alloy, tin-based alloy and bismuth-based alloy, preferably, the liquid metal is gallium-indium eutectic alloy, gallium-indium-tin eutectic alloy and gallium-indium-tin-zinc eutectic alloy, and the liquid metal has the property of presenting a liquid state at room temperature and is suitable for manufacturing flexible and stretchable conducting layers.

In some embodiments, the conductive layer 213a may be formed by etching, die cutting, evaporation, magnetron sputtering, printing, or the like. In some examples, the conductive layer 213a is formed by printing or printing using a conductive paste, the printing is not limited to extrusion printing, spray printing, direct-write printing, and the like, and the printing is not limited to screen printing, coating printing, pad printing, relief printing, gravure printing, flexo printing, and the like.

As shown in fig. 4, in some embodiments, the conductive layer 213a may be distributed on one surface of the dielectric layer to form a single-sided conductive layer.

As shown in fig. 5, in some embodiments, the conductive layer 213a may be distributed on two surfaces of the flexible substrate 211a to form a double-sided conductive layer. The conductive layers 213a on both surfaces may be interconnected by metallized vias 2111 through the flexible substrate 211.

In some embodiments, in the case where the flexible substrate 211a has a single-layer structure, the conductive layer 213a may be a single-sided conductive layer or a double-sided conductive layer; in the case where the flexible substrate 211a has a multilayer structure, the conductive layer 213a may be a single-sided conductive layer, a double-sided conductive layer, or a multilayer conductive layer.

In some embodiments, the conductive layer 213a has a pad region provided with a plurality of pads. Generally, the pad region is at least partially disposed near an edge of the conductive layer 213a. The pads of conductive layer 213a are used for soldering to PCB23 or other device. The conductive layer 213a also has connection lines for connection with the respective pads.

In some embodiments, the first cover layer 215a is attached to the surface of the conductive layer 213a away from the flexible substrate 211a to cover the connection lines of the conductive layer 213a. The first cover layer 215a may function as an insulation or waterproof or oxygen barrier. The first cover layer 215a is provided with an opening at a position corresponding to the pad area, and the size of the opening is generally larger than that of the pad area so that the pad of the pad area can be soldered to the PCB23 or other devices. Wherein, the material of the first cover layer 215a may be the same as or similar to the material of the flexible substrate 211 a.

In some embodiments, taking the FPC21 a soldered to the PCB23 as an example: a plurality of pads are arranged on the PCB23, the pads on the PCB23 correspond to the plurality of pads on the FPC21 a, and the PCB23 and the FPC21 a are soldered by the pads. In some examples, the length of the region of the PCB23 where the pads are disposed may be greater than the pad region of the FPC21 a to prevent poor soldering due to misalignment of the FPC21 a during soldering.

Fig. 6 is a schematic view illustrating bending of an FPC in the related art. Referring to fig. 6, in order to reduce the occupied space of the circuit board assembly 20, it is usually necessary to bend (or bend) the FPC21 a by an external driving force. The bending refers to the bending deformation of the FPC21 a under the action of external force, the bending change angle can be 0-180 degrees, a bending region B is formed in the bending deformation region, and a connecting line of stress concentration points on the bending surface is called as a bending line M; when the bending generates a crease, the bending line is a crease line; the bending direction P is a straight line (plane) direction perpendicular to the bending line M.

In some embodiments, the connection lines of the conductive layer 213a may be distributed only on the bending region B. In other embodiments, the connection lines of the conductive layer 213a may be distributed only on the non-bending region. In still other embodiments, the connection lines of the conductive layer 213a are distributed on both the bending region B and the non-predetermined bending region; wherein the connecting lines distributed on the bending region B and the connecting lines on the non-bending region can be connected to each other.

In some embodiments, when the connection lines of the conductive layers 213a extend substantially in the same direction, the bending direction P may be substantially parallel to the extending direction of the connection lines of the conductive layers 213a. In other words, the bending line M is substantially perpendicular to the extending direction of the connection line of the conductive layer. In this way, adverse effects on the pads of the conductive layer are advantageously reduced or even avoided, and reliability of soldering of the FPC21 a to the PCB23 or other devices is advantageously ensured.

In other embodiments, when the connection lines of the conductive layer extend in different directions, the number of the connection lines extending in one direction is greater than that of the connection lines extending in the other direction, and the bending direction P may be substantially parallel to the extending direction of the greater number of the connection lines.

Of course, the bending direction P is not limited to this, and the positional relationship between the bending direction P and the extending direction of the connecting line is merely exemplified. In concrete implementation, the bending direction P may be determined according to actual conditions.

When the FPC21 a is bent, internal stress is generated in the bending region B of the FPC21 a, and a repulsive force (or a restoring force or a repulsive force) is generated by bending. This spring back force can cause continuous stress on the connection location of the FPC to the PCB, thereby increasing the risk of failure and affecting the performance of the electronic device 100.

In addition, since the external driving force that can be provided by the miniaturized apparatus that performs the bending process on the FPC21 a is limited, it is likely to be lower than the stress of the FPC21 a itself, making it difficult for the FPC21 a to achieve the intended bending effect.

In order to overcome the above problem, the present embodiment provides an FPC21, the flexible circuit board including: the flexible printed circuit board comprises a flexible substrate, a conducting layer and a first covering layer, wherein the conducting layer is arranged on the surface of the flexible substrate, the first covering layer is arranged on the surface, far away from the flexible substrate, of the conducting layer, and the flexible printed circuit board is provided with a preset bending area. The first groove is formed in the first covering layer 215 on the surface of the FPC21, the first groove is located in a preset bending area of the FPC21, the second covering layer capable of protecting the conducting layer 213 is arranged at the first groove, and resilience of the second covering layer is lower than that of the first covering layer, so that after bending treatment, resilience of the preset bending area of the FPC21 is relatively reduced, the phenomenon of resilience of the preset bending area of the FPC21 can be reduced and even avoided, the expected bending effect of the FPC21 is favorably ensured, and the bending shape of the preset bending area is favorably maintained; moreover, the resilience of the FPC21 can meet the performance requirement of preventing the breakage of the FPC 21.

Fig. 7 is a schematic top view of an FPC according to an embodiment of the present application. The line P in fig. 7 is used to indicate a bending direction, and an included angle may also be formed between the actual bending direction in the specific implementation and the line P; the line M in fig. 7 is used to illustrate the bending line, and the actual bending line in the specific implementation may be parallel to the line M, or may have an included angle with the line M. In other words: in the specific implementation, the actual bending direction and the bending line are not limited to the above; for convenience of description, the present embodiment is described by taking the directions indicated by the lines P and M in fig. 7 as examples.

Referring to fig. 7, in some embodiments, the FPC21 has a predetermined bending region C. The preset bending region C may be a bendable region reserved on the FPC according to actual conditions. The preset bending region C may be set to be relatively large without affecting the layout of the conductive layer 213, so that the FPC21 may have more bendable positions and may be suitable for more scenes. In some examples, the predetermined bending region C is disposed to avoid the pad region so as not to affect the soldering reliability.

For example, two opposite ends of the FPC21 may be used for soldering with the PCB23 or other devices, and at least a portion of an area between the two opposite ends of the FPC21 may be used as the preset bending area C. Of course, the specific location of the predetermined bending region C on the FPC21 is not limited thereto, and may be determined according to the actual situation.

As shown in fig. 7, in some embodiments, at least one first groove 2151 may be formed in the first cover layer 215 at a position corresponding to the predetermined bending region C. The first slot 2151 may be located at least partially in the first cover layer 215 corresponding to the predefined bend region C. In some examples, to reduce the impact on the pad area on the conductive layer 213, the first groove 2151 may be located at a position of the first cover layer 215 corresponding to the pre-set bending region C, or the first groove 2151 is located in the pre-set bending region C.

In some embodiments, the first cover layer 215 may be provided with a plurality of first slots 2151 at positions corresponding to the preset bending regions C. The first slots 2151 are spaced apart. Like this, after bending, do benefit to and further reduce FPC 21's the regional C resilience force of bending of predetermineeing, can reduce or even avoid FPC 21's the regional C of predetermineeing bending to take place the resilience phenomenon, do benefit to and keep the regional C shape of bending of predetermineeing, and do benefit to and compromise FPC21 and prevent cracked performance demand.

As shown in fig. 7, in an exemplary embodiment, the first slots 2151 are spaced apart from each other in a direction parallel to the bending line M. The length direction of the first slot 2151 is parallel to the bending direction P; alternatively, when the conductive layer 213 has a connection line in a straight line segment, the length direction of the first groove 2151 is parallel to the connection line in a straight line segment, that is, the first groove extends along the direction in which the connection line of the conductive layer of the flexible circuit board extends. The first slot 2151 may have a predetermined length. Wherein, the preset length can be set according to actual needs. For example, the preset bending region C of the FPC21 has a larger length in the P direction, and the length of the first groove 2151 may be larger, accordingly, the influence of the resilient stress may be reduced when the FPC21 is bent at more bendable positions, and the FPC21 may be relatively suitable for more bending scenes.

In one possible implementation, at least some of the first slots 2151 of the plurality of first slots 2151 may be uniformly distributed, so as to ensure uniformity of the force applied throughout the predetermined bending region C. In some examples, the distance between the first slot 2151 located at the edge of the first cover layer 215 and the adjacent first slot 2151 may be set according to actual needs, wherein the first slot 2151 located at the edge of the first cover layer 215 may refer to one or more first slots 2151 located at the edge of the first cover layer 215. For example, the distance between the first groove 2151 located at the edge of the first cover layer 215 and the adjacent first groove 2151 may be smaller than the distance between the two adjacent first grooves 2151 in the middle, or the distance between the first groove 2151 located at the edge of the first cover layer 215 and the adjacent first groove 2151 may be larger than the distance between the two adjacent first grooves 2151 in the middle, or the distance between the first groove 2151 located at the edge of the first cover layer 215 and the adjacent first groove 2151 may be equal to the distance between the two adjacent first grooves 2151 in the middle.

In other embodiments, there may be one first groove 2151, the length direction of the first groove 2151 is parallel to the bending direction P, the width direction of the first groove 2151 is parallel to the bending line M, and the width of the first groove 2151 may be relatively large. This also reduces or even avoids the occurrence of spring-back in the predetermined bending region C of the FPC 21.

In other embodiments, the length direction of the first groove 2151 is parallel to the bending line M, or when the conductive layer 213 has a connection line in a straight line segment, the length direction of the first groove 2151 is perpendicular to the connection line in the straight line segment. The width direction of the first slot 2151 is parallel to the bending direction P. The number of the first slots 2151 may be one or more. This also reduces or even avoids the occurrence of spring-back in the predetermined bending region C of the FPC 21.

Fig. 8 is a schematic cross-sectional view of the FPC according to an embodiment of the present application along the direction D-D in fig. 7. Fig. 8 is a schematic view of the conductive layer 213 being a single-sided conductive layer. Referring to fig. 8 and with continued reference to fig. 7, in some embodiments, the first slot 2151 may be disposed through the first cover layer 215 in a direction perpendicular to the FPC21 (i.e., in a thickness direction of the first cover layer 215, i.e., in an up-and-down direction in fig. 8). The first slot 2151 also extends in a direction parallel to the bending direction P, or the first slot 2151 also extends in a direction substantially parallel to the connection line of the conductive layer 213. The first slot 2151 in turn extends in a direction perpendicular to the bending direction P. The first groove 2151 formed through the first cover layer 215 may have a rectangular through-hole structure, and the through-hole structure may be a through-hole in the first cover layer 215. In this way, by forming the first groove 2151 at the position of the first cover layer 215 corresponding to the preset bending region C, the flexibility of the first cover layer 215 corresponding to the position of the preset bending region C is improved, so that the preset bending region C of the FPC21 is more easily bent and deformed, the resilience is reduced, the bending shape of the preset bending region C is maintained, and the realization is facilitated.

In other embodiments, the depth of the first groove 2151 in the direction perpendicular to the FPC21 may also be less than the thickness of the first cover layer 215, and the opening of the first groove 2151 is located on the surface of the first cover layer 215 facing away from the conductive layer 213. In this way, the purpose of reducing the resiliency of the predetermined bending region of the FPC21 can also be achieved.

FIG. 9a is a schematic top view of an FPC according to another embodiment of the present disclosure; fig. 9b is a schematic top view of an FPC according to another embodiment of the present application, so as to more intuitively embody the structure in fig. 9 a. Referring to fig. 9a and 9b, in some embodiments, the conductive layer 213 may be a connection line disposed on the dielectric layer, such as an imaginary line along a vertical direction shown in fig. 9a, a portion of two adjacent imaginary lines may be regarded as a connection line, a plurality of connection lines may be disposed along the vertical direction as a portion of the conductive layer 213, a first cover layer 215 is disposed on a surface of the conductive layer 213, and the first cover layer 215 is disposed with a plurality of first slots 2151 spaced apart from each other. The first groove 2151 may be disposed at a region of the first cover layer 215 opposite to the connection line of the conductive layer 213. The second cover layer 217 is disposed at the first slot 2151, and the first slot 2151 is not shown in fig. 9a since the second cover layer 217 covers the first slot 2151. The second cover layer 217 has an insulating property. The second cover layer 217 is used to cover the connection line of the conductive layer 213 exposed in the first groove 2151, so that the second cover layer 217 serves to insulate and protect the portion of the conductive layer 213 exposed in the first groove 2151.

In some embodiments, when the first grooves 2151 are plural, the second capping layer 217 may be disposed at each of the first grooves 2151, or the second capping layer 217 may be disposed at the first groove 2151 where the conductive layer 213 is exposed. In other embodiments, when there is one first slot 2151, the first slot 2151 is filled with the flexible material and forms the second cover layer 217, or the second cover layer 217 is disposed in a position where the conductive layer 213 is exposed.

The second cover layer 217 is made of a flexible material. The second cover layer 217 is made of a flexible material having a resiliency lower than that of the first cover layer 215. The second cover layer 217 can cover at least the inner space of the first groove 2151. Thus, the resilience of the predetermined bending region C of the FPC21 can be reduced, which is advantageous for maintaining the bent shape of the predetermined bending region C.

In some examples, the thickness of the second overlayer 217 is less than the thickness of the first overlayer 215. Thus, the resilience of the predetermined bending region C of the FPC21 can be reduced, which is advantageous for maintaining the bent shape of the predetermined bending region C.

In some examples, the modulus of the flexible material used for the second coverlay 217 is lower than the modulus of the material used for the first coverlay 215, so as to facilitate increasing the elastic deformation of the second coverlay 217, increasing the flexibility of the pre-set bending region C of the FPC21, and decreasing the resilience of the pre-set bending region C of the FPC 21.

In some examples, the second coverlay 217 may be formed from a flexible material having a lower tensile strength than the material used for the first coverlay 215 to facilitate increased elastic deformation of the second coverlay 217, increased flexibility of the pre-set bend region C of the FPC21, and decreased resiliency of the pre-set bend region C of the FPC 21.

In some examples, the modulus of the flexible material used for the second overlay 217 may be half that of the material used for the first overlay 215. The flexible material used for the second cover layer 217 may have a tensile strength that is half that of the material used for the first cover layer 215. Make FPC21 predetermine bending region C softer like this, the bending deformation is easier, reduces FPC21 predetermine bending region C's resilience, does benefit to and keeps predetermine bending region C's the shape of bending, and can also compromise FPC21 and prevent cracked performance demand. In some examples, the flexible material employed for the second cover layer 217 includes a flexographic ink (also referred to as flexographic ink or flexographic ink). The type of the flexible ink in this embodiment is not particularly limited as long as the flexible ink has a lower modulus and tensile strength than the material used for the first cover layer 215 and has insulating properties. Illustratively, the flexible ink may be a black ink or a blue ink, or the like. In addition, liquid Polyimide (PI) may be used as the second cover layer 217.

Fig. 10 is a schematic partial cross-sectional view of the FPC according to an embodiment of the present application along the direction E-E in fig. 9 a. Referring to fig. 10 in combination with fig. 7 to 9a, in some embodiments, the conductive layer 213 is partially exposed in the first groove 2151. The second cover layer 217 covers a portion of the conductive layer 213 exposed in the first groove 2151, a portion of the second cover layer 217 may cover a surface of the conductive layer 213 facing away from the flexible substrate 211, and another portion of the second cover layer 217 may be connected to a side of the portion of the conductive layer 213 and extend toward the surface of the flexible substrate 211. Optionally, the second cover layer 217 extends to the surface connection of the flexible substrate 211 towards the surface of the flexible substrate 211. Thus, the insulating and protecting effects of the conductive layer 213 can be improved, and the connection reliability between the second cover layer 217 and the flexible substrate 211 and the first cover layer 215 can be improved, thereby preventing the second cover layer 217 from being separated.

It should be noted that the relative position relationship and thickness relationship between the second cover layer 217 and the first cover layer 215 in fig. 10 is only an example of the present application, and the present application is not limited thereto, for example, the width of the second cover layer 217 in the E-E direction may also be larger than that of the first slot 2151, a part of the second cover layer 217 is located in the first slot 2151, and another part of the second cover layer 217, that is, two ends of the second cover layer 217 in the E-E direction, can extend out of the first slot 2151 and be connected with the surface of the first cover layer 215 facing away from the conductive layer 213. The second cover layer 217 may also have a smaller thickness than the first cover layer 215. Thus, the contact area between the second cladding layer 217 and the first cladding layer 215 is increased, so that the connection reliability between the second cladding layer 217 and the first cladding layer 215 is improved, and the second cladding layer 217 is prevented from being separated.

Fig. 11 is a schematic cross-sectional view of the FPC with a single-sided conductive layer along the direction F-F in fig. 9 a; fig. 12 is a schematic cross-sectional view of the FPC with the double-sided conductive layer along the direction F-F in fig. 9 a. Referring to fig. 11 and 12, in some embodiments, a conductive layer 213 is disposed on a surface of the flexible substrate 211, and a first cover layer 215 is disposed on a surface of the conductive layer 213 facing away from the flexible substrate 211. The first cover layer 215 is provided with a plurality of first slots 2151 spaced apart. The connection line of the conductive layer 213 may be exposed in the first groove 2151. The second cover layer 217 is disposed at the first groove 2151. The second cladding layer 217 is sized larger than the first slot 2151. The area of the orthographic projection of the second covering layer 217 on one surface of the flexible substrate 211 is larger than the area of the orthographic projection of the first groove 2151 on the surface.

In some examples, the length of the second cladding layer 217, in a direction substantially perpendicular to the bending direction, is greater than the length of the first slot 2151; the second cover 217 has a length direction (substantially perpendicular to the bending direction) identical to the length direction of the flexible first groove 2151. A portion of the second cover layer 217 is located in the first slot 2151, and another portion of the second cover layer 217, i.e., both ends of the second cover layer 217 in the length direction, can extend out of the first slot 2151 and be connected to a surface of the first cover layer 215 facing away from the conductive layer 213. Thus, the contact area between the second cladding layer 217 and the first cladding layer 215 is increased, so that the connection reliability between the second cladding layer 217 and the first cladding layer 215 is improved, and the second cladding layer 217 is prevented from being separated.

In other examples, the width of the second cover layer 217 is greater than the first slot 2151, and the width direction of the second cover layer 217 is the same as the width direction of the first slot 2151; this also improves the reliability of connection between the second clad layer 217 and the first clad layer 215.

The thickness of the portion of the second cover layer 217 located in the first slot 2151 may be smaller than the thickness of the first cover layer 215, so as to further reduce the flexibility of the pre-set bending region. For example, the thickness of the portion of the second cladding layer 217 located in the first groove 2151 may be greater than or equal to half the thickness of the first cladding layer 215, which is advantageous for ensuring insulation protection of the portion of the conductive layer exposed in the first groove 2151. In addition, the thickness of the portion of the second cover layer 217 extending out of the first groove 2151 may be less than or equal to the thickness of the portion of the second cover layer 217 located in the first groove 2151.

Fig. 13 is a schematic diagram illustrating the arrangement of the second coverlay 217 on the FPC according to an embodiment of the present application. Referring to fig. 13, in some embodiments, the pad region of the conductive layer 213 and the adjacent second cover layer 217 may have a first minimum distance L1 therebetween. The first minimum distance L1 may refer to a minimum distance between an orthographic projection of the pad region and the adjacent second cover layer 217 on one surface of the flexible substrate 211. The first minimum distance L1 is greater than or equal to a first threshold. In this way, the second coverlay 217 can be prevented from interfering with the reliability of soldering of the pad region with the PCB23 or other devices.

For example, as shown in fig. 13, when there is a portion of the second cover layer 217 relatively close to the edge of the first cover layer 215 and the corresponding edge of the conductive layer 213 is provided with a pad region, the first minimum distance L1 between the second cover layer 217 relatively close to the edge of the first cover layer 215 and the pad region needs to be greater than or equal to the first threshold value.

The specific values of the first threshold and the first minimum distance L1 may be determined according to actual situations. For example, the first threshold may be 1.5 microns and the first minimum distance L1 may be greater than or equal to 1.5 microns. For example, the first minimum distance L1 may be 1.5 microns, or 1.6 microns, or 1.7 microns, or 1.8 microns, or 1.9 microns, or 2.0 microns. The first minimum distance L1 may be any value between any two of the above values. In this way, it is advantageous to avoid the second cover layer 217 from interfering with the reliability of the soldering of the pads of the pad area with the PCB23 or other devices. Of course, the first minimum distance L1 should not be too large, which is beneficial to provide more first slots 2151 and second cover layers 217 to reduce the resilience of the predetermined bending region C. It should be noted that: the numerical values in this embodiment are only examples, and the numerical value of the first minimum distance is not limited to this in specific implementations.

With continued reference to fig. 13, in some embodiments, when the second cover layer 217 is disposed near the edge of the first cover layer 215, the second cover layer 217 may have a second minimum distance L2 from the corresponding edge of the first cover layer 215. The second minimum distance L2 is greater than or equal to a second threshold. In this way, it is advantageous to ensure the connection reliability of the second cover layer 217 and the first cover layer 215 near the edge, and to ensure the protective effect on the conductive layer 213.

The specific values of the second threshold and the second minimum distance L2 may be determined according to actual situations. The second threshold may be equal to the first threshold, or the second threshold may be greater than the first threshold. For example, the second threshold may be 1.5 microns. The second minimum distance L2 may be greater than or equal to 1.5 micrometers. The second minimum distance L2 may be 2 micrometers or less. For example, the second minimum distance L2 may be 1.5 microns, or 1.75 microns, or 2.0 microns. The second minimum distance L2 may be any value between any two of the above values. This is advantageous in ensuring the reliability of the connection between the second cover layer 217 and the first cover layer 215, and in reducing the resilience of the predetermined bending region C by providing more first grooves 2151 and second cover layers 217. It should be noted that: the numerical values in this embodiment are only examples, and the numerical values of the second minimum distance L2 are not limited thereto in specific implementations.

Fig. 14a is a first schematic structural diagram of an FPC according to yet another embodiment of the present application; fig. 14b is a schematic structural diagram of a FPC according to yet another embodiment of the present application, so as to more intuitively embody the structure in fig. 14 a; fig. 15 is a schematic cross-sectional view of the FPC with a single-sided conductive layer along the direction G-G in fig. 14 a; fig. 16 is a schematic cross-sectional view of the FPC with double-sided conductive layers along the G-G direction in fig. 14 a.

Referring to fig. 14a to 16, the first cover layer 215 further has at least one second groove 2152 at a position corresponding to the predetermined bending region C. The second groove 2152 may be offset from the connection line disposed between the first cover layer 215 and the conductive layer 213. That is, the flexible substrate is located below the position of the first cover layer 215 where the second groove 2152 is opened.

In a possible implementation manner, a plurality of first slots and a plurality of second slots are arranged on the first covering layer, and at least part of the first slots and the second slots are distributed at intervals. At least part of the first slots and the second slots are spaced apart, which means that one or more second slots are arranged between at least part of the first slots and the adjacent first slots. For example, one or more second slots are provided between each first slot and another adjacent first slot. The relative position relationship of the first slot and the second slot is not limited herein.

In an example of the present application, as shown in fig. 14a and 14b, the second slots 2152 may be spaced apart from the first slots 2151, that is, one second slot 2152 is disposed between each first slot 2151 (the first slot 2151 is covered by the second cover 217) and the adjacent first slot 2151; the first opening 2151 may be disposed at a position corresponding to a connection line between the first cover layer 213 and the conductive layer 213, and the second opening 2152 may be disposed to be offset from the second cover layer 217 disposed at the first opening 2151. In this way, by providing the second groove 2152, flexibility of the first cover layer 215 at a position corresponding to the predetermined bending region C is further improved, so that the predetermined bending region C of the FPC21 is more easily bent and deformed, and the resilience is reduced, thereby facilitating retention of the bent shape of the predetermined bending region C.

In some examples, the second slot 2152 may be located at least partially in the first cladding layer 215 corresponding to the predefined bend region C. The length of the second slot 2152 may be greater than or equal to the length of the second cladding layer 217. The second groove 2152 may extend in a length direction to the outside of the predetermined bending region C, and may extend along a direction in which a connection line of the conductive layer of the flexible circuit board extends.

In some examples, the second slot 2152 may be disposed through the first cover layer 215. In other examples, the depth of the second groove 2152 may be less than the thickness of the first cover layer 215, and the opening of the second groove 2152 is located on the surface of the first cover layer 215 facing away from the conductive layer 213.

The width of the second groove 2152 may be equal to the distance between two adjacent second cover layers 217, which facilitates the connection of the second cover layer 217 in the first groove 2151 with the flexible substrate 211 to prevent the second cover layer 217 from falling off. Of course, the width of the second groove 2152 may be smaller than the interval between two adjacent second cover layers 217.

In some examples, a portion of the second groove 2152 may be located between two adjacent second cover layers 217, and a distance between two adjacent second cover layers 217 may be greater than or equal to a width of the second cover layers 217, so that a portion of the second groove 2152 located between two adjacent second cover layers 217 may be relatively large, which is beneficial to increase a layout area of the second groove 2152, further improve flexibility of the first cover layer 215 corresponding to the predetermined bending area C, and reduce resilience.

For example, the width of the second cover layer 217 may be 0.25 micrometers, the distance between two adjacent second cover layers 217 may be greater than or equal to 0.25 micrometers, or the width of the second groove 2152 may be greater than or equal to 0.25 micrometers; for example, the width of the second slot 2152 may be 0.25 microns, or 0.3 microns, or 0.35 microns, or 0.4 microns, or 0.45 microns, or 0.5 microns, or 0.55 microns; the width of the second slot 2152 can also be any value between any two of the above values. It should be noted that: the numerical values in this embodiment are only examples, and the numerical value of the width of the second groove 2152 is not limited to this.

In some examples, the width of the second slot 2152 may be twice the width of the second cladding layer 217; for example, the width of the second capping layer 217 may be 0.25 micrometers, and the interval between two second capping layers 217 may be 0.5 micrometers.

In one possible implementation, the flexible substrate of the predetermined bending region is provided with a third slot. The third opening may be disposed through the flexible substrate; alternatively, the depth of the third slot may be smaller than the thickness of the flexible substrate, and the opening of the third slot is located on the surface of the flexible substrate, for example, on the surface of the flexible substrate away from the conductive layer. In one possible implementation, the third opening may be disposed to be offset from the connection line of the conductive layer. For example, the third slot may be opposite to the second slot, and the opposite arrangement may mean that the third slot corresponds to the second slot, for example, the third slot may be the same as the second slot. In a possible implementation manner, the third slot and the second slot may be disposed in communication. Fig. 15 and 16 show examples of the arrangement of the third open groove and the second open groove according to an embodiment of the present application. The present application is not limited to the arrangement of fig. 15 and 16.

In some embodiments, with reference to fig. 15 and fig. 16, the flexible substrate 211 has at least one third opening 2112 at a position corresponding to the predetermined bending region C. The third opening 2112 may be located at a position shifted from a connection line provided between the flexible substrate 211 and the conductive layer 213. In this way, by providing the third open groove 2112, it is beneficial to improve the flexibility of the flexible substrate 211 corresponding to the position of the preset bending region C, so that the preset bending region C of the FPC21 is more easily bent and deformed, the resilience is reduced, it is beneficial to maintain the bending shape of the preset bending region C, and it is convenient to implement.

In some examples, the third opening 2112 may be at least partially located at a position of the flexible substrate 211 corresponding to the predetermined bending region C. The length of the third opening 2112 may be greater than the length of the second cover layer 217. The third groove 2112 may extend in the longitudinal direction beyond the predetermined bending region C.

The third opening 2112 may be plural. The third opening 2112 may be provided to be offset from the first opening 2151, and in the example of fig. 15 and 16, the third opening 2112 corresponds to the position of the second opening 2152. The portion of the third slot 2112 corresponding to the second slot 2152 may be in communication with the second slot 2152, so as to improve flexibility of the preset bending region C, reduce resilience of the preset bending region C, maintain toughness of the preset bending region, and prevent fracture.

In some examples, the third slot 2112 can be the same size as the second slot 2152. In other examples, the size of the third slot 2112 may be slightly larger or smaller than the size of the second slot 2152.

Here, the width of the third opening 2112 may be equal to the distance between two adjacent second cover layers 217, or the width of the third opening 2112 may be smaller than the distance between two adjacent second cover layers 217. The length of the third opening 2112 may be greater than or equal to the length of the second cover layer 217. In this way, the second cover layer 217 in the first groove 2151 is facilitated to be connected to the flexible substrate 211 to prevent the second cover layer 217 from falling off.

In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, a fixed connection, an indirect connection via an intermediary, a connection between two elements, or an interaction between two elements. The specific meanings of the above terms in the embodiments of the present application can be understood by those of ordinary skill in the art according to specific situations.

Reference throughout this specification to apparatus or components, in embodiments or applications, means or components must be constructed and operated in a particular orientation and therefore should not be construed as limiting the present embodiments. In the description of the embodiments of the present application, "a plurality" means two or more unless specifically stated otherwise.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the embodiments of the application and in the drawings described above, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The term "plurality" herein means two or more. The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship; in the formula, the character "/" indicates that the preceding and following related objects are in a relationship of "division".

It is to be understood that the various numerical references referred to in the embodiments of the present application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of the present application.

It should be understood that, in the embodiment of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiment of the present application.

Claims (11)

1. The flexible circuit board is characterized in that the flexible circuit board is provided with a preset bending area;

the flexible circuit board includes: the flexible substrate comprises a flexible substrate, a conducting layer and a first covering layer, wherein the conducting layer is arranged on the surface of the flexible substrate, and the first covering layer is arranged on the surface, far away from the flexible substrate, of the conducting layer;

the position of the first covering layer corresponding to the preset bending area is provided with a plurality of first grooves and a plurality of second grooves, and at least part of the first grooves and the second grooves are distributed at intervals; the first open groove and the second open groove penetrate through the first covering layer; the first open slot is arranged at a position corresponding to the connecting line of the first covering layer and the conducting layer, and the second open slot is arranged at a staggered position of the connecting line of the first covering layer and the conducting layer;

wherein, a second covering layer with lower resilience than the first covering layer is arranged at the first open groove and is used for covering the conducting layer in the first open groove;

the flexible substrate in the preset bending area is provided with a third open slot, and the third open slot and the connecting line of the conducting layer are arranged in a staggered mode.

2. The flexible circuit board of claim 1, wherein the third slot is in communication with the second slot.

3. The flexible circuit board according to claim 1 or 2, wherein the third opening is provided through the flexible substrate.

4. The flexible circuit board according to any one of claims 1 to 3, wherein the first slot and/or the second slot extend along a direction in which a connection line of the conductive layer of the flexible circuit board extends.

5. The flexible circuit board of any one of claims 1 to 3, wherein the thickness of the second coverlay is less than the thickness of the first coverlay.

6. The flexible circuit board of any one of claims 1 to 3, wherein the modulus of the second coverlay is lower than the modulus of the first coverlay.

7. The flexible circuit board of claim 6, wherein the modulus of the second coverlay is half of the modulus of the first coverlay.

8. The flexible circuit board of any one of claims 1 to 3, wherein the second coverlay has a tensile strength that is lower than the tensile strength of the first coverlay.

9. The flexible circuit board of claim 8, wherein the tensile strength of the second coverlay is half of the tensile strength of the first coverlay.

10. The flexible circuit board of any one of claims 1 to 3, wherein a portion of the second cover layer is located in the first slot and another portion of the second cover layer extends out of the first slot and is connected to a surface of the first cover layer.

11. An electronic device, comprising: a housing and a flexible circuit board as claimed in any one of claims 1 to 10, the flexible circuit board being disposed in the housing space of the housing.

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