CN114340145A

CN114340145A - Flexible circuit board and display device

Info

Publication number: CN114340145A
Application number: CN202210005128.1A
Authority: CN
Inventors: 王梓鉴; 陆旭
Original assignee: BOE Technology Group Co Ltd; Chengdu BOE Optoelectronics Technology Co Ltd
Current assignee: BOE Technology Group Co Ltd; Chengdu BOE Optoelectronics Technology Co Ltd
Priority date: 2022-01-04
Filing date: 2022-01-04
Publication date: 2022-04-12

Abstract

The utility model relates to a show technical field, especially relate to a flexible line way board and display device for promote display device's product yield. The flexible wiring board includes a substrate, a conductive layer, and a protective layer. The conductive layer is arranged on the substrate. The protective layer is arranged on one side of the conducting layer, which is far away from the substrate, and a plurality of openings are formed in the protective layer. The portion of the conductive layer exposed by the opening serves as a pad. The openings are arranged along a first direction, and a plurality of rows are arranged along a second direction, and the first direction is intersected with the second direction; the plurality of openings comprise at least one first opening and a plurality of second openings, the second openings are uniformly distributed on two sides of the at least one first opening, and the orthographic projection area of the first openings on the substrate is larger than that of the second openings on the substrate. The area of the first opening is increased, so that the amount of the solder paste which can be filled in the corresponding bonding pad is increased, the problem of insufficient soldering is avoided, and the product yield of the display device is improved.

Description

Flexible circuit board and display device

Technical Field

The present disclosure relates to the field of display technologies, and in particular, to a flexible printed circuit and a display device.

Background

With the continuous development of electronic products, Organic Light-Emitting Diode (OLED) display devices are widely used because they can realize full-screen, narrow-frame, high-resolution, curling, wearing, folding, and the like.

The product yield and the service life of the display device are one of the most important performances of electronic products, and how to ensure effective electrical connection among all parts of the display device so as to improve the product yield and the service life of the display device is a problem which is consistently explored in the industry.

Disclosure of Invention

The embodiment of the disclosure provides a flexible circuit board and a display device, aiming at solving the problem of insufficient soldering generated in the welding process of the flexible circuit board and a component, thereby avoiding the signal line of the display device from being broken, ensuring the effective electric connection among all parts of the display device, and improving the product yield and the service life of the display device.

In order to achieve the purpose, the embodiment of the disclosure adopts the following technical scheme:

in one aspect, a flexible wiring board is provided, the flexible wiring board comprising: a substrate, a conductive layer and a protective layer.

Wherein the conductive layer is disposed on the substrate. The protective layer is arranged on one side, far away from the substrate, of the conductive layer, and a plurality of openings are formed in the protective layer. The portion of the conductive layer exposed by the opening serves as a pad.

The openings are arranged along a first direction, and a plurality of rows are arranged along a second direction, and the first direction is intersected with the second direction; the plurality of openings comprise at least one first opening and a plurality of second openings, the second openings are uniformly distributed on two sides of the first opening, and the area of the orthographic projection of the first opening on the substrate is larger than that of the second opening on the substrate.

Through increasing first open-ended size, soldering tin (conductive part) volume that the pad that makes first opening correspond can be filled increases to guarantee that the needs welded pin that first opening corresponds is wrapped up by soldering tin completely, avoid because soldering tin volume is not enough to lead to the unable complete problem that wraps up the pin of soldering tin and cause the rosin joint, avoid display device's signal line to take place to open circuit, improve display device's product yield and life.

In some embodiments, the opening is elongated. The size of the first opening along the first direction is larger than that of the second opening along the first direction; and/or the size of the first opening along the second direction is larger than the size of the second opening along the second direction.

In some embodiments, the at least one first opening is arranged mirror-symmetrically in the first direction, wherein an axis of symmetry extends in the second direction.

In some embodiments, the at least one first opening is equal in size in the first direction and the at least one first opening is equal in size in the second direction; the plurality of second openings are equal in size in the first direction, and the plurality of second openings are equal in size in the second direction.

In some embodiments, along the first direction and a direction close to the at least one first opening, an area of an orthographic projection of the second opening on the substrate gradually increases.

In some embodiments, along the first direction and a direction close to the symmetry axis, an area of an orthographic projection of the first opening on the substrate gradually increases.

In some embodiments, the centers of the plurality of openings are all located on a same straight line extending in the first direction.

In some embodiments, the first opening has a dimension in the first direction of 0.17cm to 0.20cm, and the first opening has a dimension in the second direction of 0.48cm to 0.49 cm.

In some embodiments, the dimension of the second opening along the first direction is 0.15cm to 0.16cm, and the dimension of the second opening along the second direction is 0.47cm to 0.48 cm.

In some embodiments, the ratio of the number of first openings to the number of second openings is 1: 0.6-1: 2.0.

in some embodiments, the flexible printed circuit further includes a conductive film disposed on an inner wall formed by an opening formed in the protective layer, and the conductive film is electrically connected to the conductive layer.

In some embodiments, the flexible circuit board further comprises a shielding layer arranged on one side of the protective layer away from the substrate, and the shielding layer is configured to shield external signal interference; the shielding layer is provided with a plurality of through holes, and the through holes are communicated with the openings so as to expose the bonding pads.

In another aspect, there is provided a display device including: the flexible wiring board, the driver circuit board, and the plurality of conductive portions according to any of the preceding embodiments.

Wherein the driver circuit board includes a connector including a plurality of pins. The conductive parts are arranged between the flexible circuit board and the driving circuit board, at least part of the conductive parts are positioned in the opening of the flexible circuit board and are electrically connected with the bonding pad at the opening, and the conductive parts are also electrically connected with the pins.

In some embodiments, the plurality of conductive portions are arranged in a first direction; the plurality of conductive parts comprise at least one first conductive part and a plurality of second conductive parts, the plurality of second conductive parts are uniformly arranged on two sides of the at least one first conductive part, and the volume of the first conductive part is larger than that of the second conductive part.

In some embodiments, a dimension of the first conductive portion in a thickness direction perpendicular to the substrate of the flexible circuit board is larger than a dimension of the second conductive portion in the thickness direction perpendicular to the substrate of the flexible circuit board.

It can be understood that, the beneficial effects that the display device provided by the above embodiments of the present disclosure can achieve can refer to the beneficial effects of the flexible circuit board in the foregoing, and are not described herein again.

Drawings

In order to more clearly illustrate the technical solutions in the present disclosure, the drawings needed to be used in some embodiments of the present disclosure will be briefly described below, and it is apparent that the drawings in the following description are only drawings of some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art according to the drawings. Furthermore, the drawings in the following description may be regarded as schematic diagrams, and do not limit the actual size of products, the actual flow of methods, the actual timing of signals, and the like, involved in the embodiments of the present disclosure.

FIG. 1 is a block diagram of a display device provided in accordance with some embodiments;

FIG. 2 is an exploded view of a display device provided in accordance with some embodiments;

FIG. 3 is a diagram of a connection structure of a flexible printed circuit board and a driving circuit board according to some embodiments;

FIG. 4 is a cross-sectional view taken along section line A-A' of FIG. 3;

FIG. 5 is another cross-sectional view taken along section line A-A' of FIG. 3;

FIG. 6 is another cross-sectional view taken along section line A-A' of FIG. 3;

FIG. 7 is a block diagram of a pad area of a flexible wiring board provided in accordance with some embodiments;

FIG. 8 is a structural diagram corresponding to the B region in FIG. 7;

FIG. 9 is another block diagram of a pad area of a flexible wiring board provided in accordance with some embodiments;

FIG. 10 is a structural diagram corresponding to the area C in FIG. 6;

fig. 11 is a block diagram of a flexible wiring board provided in accordance with some embodiments.

Detailed Description

Technical solutions in some embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments provided by the present disclosure belong to the protection scope of the present disclosure.

Unless the context requires otherwise, throughout the description and the claims, the term "comprise" and its other forms, such as the third person's singular form "comprising" and the present participle form "comprising" are to be interpreted in an open, inclusive sense, i.e. as "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" and the like are intended to indicate that a particular feature, structure, material, or characteristic associated with the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic representations of the above terms are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be included in any suitable manner in any one or more embodiments or examples.

In the following, the terms "first", "second" are used for descriptive purposes only and are not to be understood 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 of that feature. In the description of the embodiments of the present disclosure, "a plurality" means two or more unless otherwise specified.

In describing some embodiments, expressions of "electrically connected" and "connected" and derivatives thereof may be used. For example, the term "electrically connected" may be used in describing some embodiments to indicate that two or more elements are in direct physical or electrical contact with each other. The embodiments disclosed herein are not necessarily limited to the contents herein.

"A and/or B" includes the following three combinations: a alone, B alone, and a combination of A and B.

It will be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present.

Example embodiments are described herein with reference to cross-sectional and/or plan views as idealized example figures. In the drawings, the thickness of layers and regions are exaggerated for clarity. Variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, the exemplary embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the exemplary embodiments.

Fig. 1 is a top view of a display device 100 provided by some embodiments of the present disclosure. The display device 100 may be any device that displays images, whether in motion (e.g., video) or stationary (e.g., still images), and whether textual or textual. More particularly, it is contemplated that embodiments may be implemented in or associated with a variety of electronic devices such as, but not limited to, mobile telephones, wireless devices, Personal Data Assistants (PDAs), hand-held or portable computers, Global Positioning System (GPS) receivers/navigators, cameras, MP4 video players, video cameras, game consoles, wrist watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer display, etc.), navigators, cockpit controls and/or displays, displays of camera views (e.g., of a rear view camera in a vehicle), electronic billboards or signs, projectors, architectural structures, packaging, and aesthetic structures (e.g., a display of an image for a piece of jewelry) and the like. Fig. 1 illustrates the display device 100 as a mobile phone.

Fig. 2 shows an exploded view of the display device 10 of fig. 1. As shown in fig. 2, the display device 100 includes a display panel 200, a flexible wiring board 300, and a driving circuit board 400.

The flexible printed circuit board 300 may be bound to the display panel 200. Note that the flexible printed circuit 300 may be bent around the dotted line L toward the back surface of the display panel 200 (i.e., the surface opposite to the display surface of the display panel 200) so that the flexible printed circuit 300 is located on the back surface of the display panel 200.

As shown in fig. 2 and 3, the driving circuit board 400 includes a connector H, and the driving circuit board 400 and the flexible circuit board 300 are electrically connected through the connector H, and the connector H is exemplarily soldered to the flexible circuit board 300.

As shown in fig. 3, the flexible wiring board 300 includes a pad region Q, a long side QL of the pad region Q extending in a first direction X, and a central line Qh of the long side QL of the pad region Q extending in a second direction Y. Wherein the first direction X and the second direction Y are mutually crossed. For example, the first direction is perpendicular to the second direction.

Illustratively, the connector H is soldered to the flexible wiring board 300 at the land area Q

Figure 4 shows a cross-sectional view along section line a-a' in figure 3. As shown in fig. 4, the display device 100 further includes a plurality of conductive portions T disposed at the pad region Q. The flexible wiring board 300 and the connector H are soldered by the conductive portion T.

Illustratively, the conductive portion T is formed by curing a paste mixture containing a metal or an alloy, for example, the conductive portion T is formed by curing a solder paste, a copper-phosphorus solder paste, or a silver solder paste at a high temperature.

The material of the conductive portion T may further include a flux, a surfactant, a thixotropic agent, and the like.

As shown in fig. 4, the connector H includes a plurality of pins P, which are electrically connected to the conductive portions T.

Illustratively, the leads P extend into the interior of the conductive portion T. For example, the pin P includes a trunk portion P1 and a soldering portion P2, the trunk portion P1 and the soldering portion P2 are bent at an angle, and the soldering portion P2 extends into the interior of the conductive portion T, so as to ensure that the soldering between the connector H and the flexible circuit board 300 is relatively firm.

In the related art, after the conductive portion T in the paste mixture state is placed on the pad region Q, the solid conductive portion T is cured in a high temperature environment. For example, the conductive portion T is cured by a reflow technique, thereby achieving soldering between the conductive portion T and the pin P, and soldering between the conductive portion T and the flexible wiring board 300.

As shown in fig. 5, the inventors of the present disclosure have studied and found that the connector H 'of the driving circuit board 400' is easily deformed by heat under the influence of a high temperature environment during the curing process. For example, the connector H' may appear to arch in an arc. Referring to fig. 5, the middle portion of the connector H ' is far away from the flexible circuit board 300 ' relative to the two ends, and the pin P ' located in the middle portion of the connector H ' is driven to be far away from the flexible circuit board 300 ', which may cause insufficient contact between the pin P ' and the conductive portion T ' to reduce the connection strength, or even cause the pin P ' and the conductive portion T ' to be disconnected, so that the display device 100 may have a cold joint problem.

Note that the case of "cold joint" includes: 1. the pin P 'is not in contact with the conductive part T', and is directly disconnected, so that disconnection is caused; 2. there is contact between the pin P ' and the conductive portion T ', but the position where the pin P ' extends into the conductive portion T ' is shallow, for example, the welding portion P2 ' of the pin P ' is not completely wrapped by the conductive portion T ', the welding strength is low, and the joint between the pin P ' and the conductive portion T ' is easily broken in the subsequent process and the product use process, resulting in an open circuit.

As shown in fig. 6, in some embodiments of the present disclosure, the plurality of conductive portions T are arranged along the first direction X.

Illustratively, the plurality of conductive portions T may be arranged in a plurality of rows each extending in the first direction X along the second direction Y. For example, the plurality of conductive portions T are arranged in two rows along the second direction Y.

In each row of conductive portions T, the plurality of conductive portions T includes at least one first conductive portion T1 and a plurality of second conductive portions T2, and the plurality of second conductive portions T2 are uniformly disposed on both sides of the at least one first conductive portion T1. That is, at least one first conductive portion T1 is located at the middle of the pad region Q.

Illustratively, the at least one first conductive portion T1 is located close to a center line Qh of the pad region Q in the second direction Y with respect to the plurality of second conductive portions T2.

Illustratively, the plurality of second conductive portions T2 are arranged in mirror symmetry with respect to a center line Qh of the pad region Q in the second direction Y as a symmetry axis.

Illustratively, the at least one first conductive portion T1 is arranged in mirror symmetry with respect to a center line Qh of the pad region Q in the second direction Y as a symmetry axis.

The first conductive portion T1 is provided with a volume larger than that of the second conductive portion T2. That is, among the plurality of conductive portions T, the conductive portion T for connecting the pin P located in the middle of the connector H is large in volume, so that the conductive portion T for welding with the pin P in the middle of the connector H can still completely wrap the welding portion P2 of the pin P under the condition that the connector H undergoes arching deformation, thereby avoiding the problem of cold joint.

As shown in fig. 6, the dimension of the first conductive portion T1 in the direction Z perpendicular to the thickness direction of the flexible circuit board 300 is illustratively larger than the dimension of the second conductive portion T2 in the direction Z perpendicular to the thickness direction of the flexible circuit board. That is, the first thickness d1 of the conductive part T soldered to the pins P in the middle of the connector H is greater than the second thickness d2 of the conductive parts T soldered to the pins P at both ends of the connector H.

Illustratively, the thickness of the conductive portion T becomes gradually thicker along the first direction and the direction near the center line Qh. For example, the thickness of the conductive portion T becomes thicker in sequence or becomes thicker in steps.

By making the first thickness d1 of the first conductive portion T1 arranged in the middle of the pad region Q greater than the second thickness d2 of the second conductive portion T2 relatively far away from the center line Qh of the pad region Q, the pin P in the middle of the connector H can still extend into the conductive portion T under the condition that the connector H is heated to arch, for example, the conductive portion T can completely wrap the welding portion P2, thereby avoiding the problem that the pin P is disconnected from the conductive portion T or the joint strength is low due to the arch phenomenon of the connector H, reducing the cold joint phenomenon, and improving the product yield and the service life of the display device 100.

As shown in fig. 6, in some embodiments of the present disclosure, the flexible wiring board 300 includes: a substrate 10, a conductive layer 20, and a protective layer 30.

The substrate 10 is a flexible substrate, and may be, for example, one or more combinations of polyethylene terephthalate, ethylene terephthalate, polyetheretherketone, polystyrene, polycarbonate, polyarylate, polyimide, polyvinyl chloride, polyethylene, and textile fiber, and the embodiments of the present disclosure are not limited thereto.

The conductive layer 20 is provided on the substrate 10.

Illustratively, a plurality of signal lines are disposed in the conductive layer 20, and the plurality of signal lines are electrically connected to the driving circuit board 400 through a connector H, so as to realize signal transmission between the driving circuit board 400 and the flexible circuit board 300.

Illustratively, the material of the conductive layer 20 includes a metal material, such as copper.

The protective layer 30 is disposed on a side of the conductive layer 20 away from the substrate 10. The protective layer 30 is configured to insulate the conductive layer 20 from other components and prevent shorting.

The material of the protective layer 30 is not limited. Illustratively, the material of the protection layer 13 may be a Polyimide Film (PI).

Illustratively, the protective layer 30 is made of an insulating material and an adhesive, and covers the conductive layer 20 to protect and insulate the conductive layer 20.

Illustratively, the flexible wiring board 300 is a double-layer board, that is, the flexible wiring board 300 includes two conductive layers 20. As shown in fig. 6, the conductive layer 20 is disposed on the side of the substrate 10 close to and far from the driving circuit board 400, and similarly, the protective layer 30 is disposed on the side of each conductive layer 20 far from the substrate 10.

As shown in fig. 7, the passivation layer 30 has a plurality of openings K. Illustratively, the plurality of openings K are located at the pad region Q.

The portion of the conductive layer 20 exposed by the opening K serves as a pad S, and illustratively, the portion of the signal line of the conductive layer 20 exposed by the opening K forms the pad S.

The pad S is configured to be soldered to the conductive portion T, so as to electrically connect the flexible wiring board 300 and the conductive portion T, and finally transmit an electrical signal transmitted by the pad S, i.e., the conductive layer 20, to the connector H, i.e., the driving circuit board 400, through the conductive portion T.

As shown in fig. 7, the plurality of openings K are arranged in the first direction X, the plurality of openings K are arranged in a plurality of rows in the second direction Y, and referring to fig. 7, the plurality of openings K are arranged in two rows in the second direction Y.

As shown in fig. 7, the plurality of openings K includes at least one first opening K1 and a plurality of second openings K2, and the plurality of second openings K2 are uniformly disposed at both sides of the at least one first opening K1, that is, the at least one first opening K1 is disposed at the middle of the pad region Q.

Illustratively, the first opening K1 is close to the center line Qh of the pad region Q with respect to the second opening K2.

As shown in fig. 7, an area of an orthogonal projection of the first opening K1 on the substrate 10 is larger than an area of an orthogonal projection of the second opening K2 on the substrate 10.

That is, the area of the pad S near the center line Qh of the pad region Q is larger than the area of the pad S far from the center line Qh of the pad region Q, so that the amount of the conductive part T near the center line Qh of the pad region Q is larger than the amount of the conductive part T far from the center line Qh of the pad region Q, that is, the thickness of the conductive part T to which the pin pweld in the middle of the connector H is welded is larger than the thickness of the conductive part T to which the pin pweld at the two ends of the connector H is welded.

After research, the inventors of the present disclosure found that, before curing, the conductive portion T is a viscous fluid (i.e., a paste mixture), and during the curing process, the more the amount (e.g., volume) of the conductive portion T is due to interference of a temperature field and viscosity of the fluid, the thicker the conductive portion T is after curing is completed. Therefore, by making the area of the orthographic projection of the first opening K1 on the substrate 10 larger than the area of the orthographic projection of the second opening K2 on the substrate 10, the amount of the conductive part T close to the center line Qh of the pad region Q is larger than the amount of the conductive part T far away from the center line Qh of the pad region Q, and the thickness of the conductive part T close to the center line Qh of the pad region Q is larger than the thickness of the conductive part T far away from the center line Qh of the pad region Q, so as to ensure that the leads P at the arching position can be completely wrapped by the conductive part T under the condition that the middle of the connector H is arched, thereby avoiding the problem of insufficient soldering during the reflow soldering process (i.e. the curing process), avoiding the occurrence of the disconnection of the signal lines, and improving the product yield and the service life of the display device 100.

As shown in fig. 8, in some embodiments, the opening K is elongated.

Illustratively, the shape of the opening K is rectangular, an elongated hexagon, an elongated polygon, or an ellipse, etc.

It is understood that the shape of the portion of the conductive layer 20 exposed by the opening K (i.e., the pad S) is also a long bar.

As shown in fig. 8, exemplarily, the width L1 of the opening K extends along the first direction X, that is, the size of the opening K along the first direction X is the width L1 of the opening K; the length L2 of the opening K extends along the second direction Y, i.e. the dimension of the opening K along the second direction Y is the length L2 of the opening K.

As shown in fig. 8, the size of the first opening K1 in the first direction X is larger than the size of the second opening K2 in the first direction X. For example, the width L1 of the first opening K1 is greater than the width L1' of the second opening K2, and accordingly, the width of the pad S corresponding to the first opening K1 is greater than the width of the pad S corresponding to the second opening K2.

By providing the first opening K1 with a size in the first direction X larger than that of the second opening K2, so that the size of the pad S corresponding to the first opening K1 in the first direction X is greater than the size of the pad S corresponding to the second opening K2 in the first direction X, thereby increasing the area of the pad S corresponding to the first opening K1, increasing the amount of the conductive portion T that can be filled, so that, during the curing process, the thickness of the conductive portion T corresponding to the first opening K1 is made greater than the thickness of the conductive portion T corresponding to the second opening K2, that is, in the case of the connector H with the center portion arched, the thickness of the conductive portion T corresponding to the pin P in the center portion is thickened accordingly, therefore, the pins P can be completely wrapped by the conductive part T under the condition that the middle part of the connector H is arched, the problem of insufficient soldering is avoided, and the product yield and the service life of the display device 100 are improved.

In some embodiments, as shown in fig. 8, the size of the first opening K1 in the second direction Y is greater than the size of the second opening K2 in the second direction Y. For example, the length L2 of the first opening K1 is greater than the length L2' of the second opening K2, and accordingly, the length of the pad S corresponding to the first opening K1 is greater than the length of the pad S corresponding to the second opening K2.

By providing the size of the first opening K1 in the second direction Y to be larger than the size of the second opening K2 in the second direction Y, so that the size of the pad S corresponding to the first opening K1 in the second direction Y is greater than the size of the pad S corresponding to the second opening K2 in the second direction Y, thereby increasing the area of the pad S corresponding to the first opening K1, increasing the amount of the conductive portion T that can be filled, so that, during the curing process, the thickness of the conductive portion T corresponding to the first opening K1 is made greater than the thickness of the conductive portion T corresponding to the second opening K2, that is, in the state that the middle part of the connector H is arched, the thickness of the conductive part T corresponding to the pin P in the middle part is correspondingly thickened, therefore, the pins P can be completely wrapped by the conductive part T under the condition that the middle part of the connector H is arched, the problem of insufficient soldering is avoided, and the product yield and the service life of the display device 100 are improved.

In some embodiments, as shown in fig. 8, the size of the first opening K1 in the first direction X is greater than the size of the second opening K2 in the first direction X, while the size of the first opening K1 in the second direction Y is greater than the size of the second opening K2 in the second direction Y. For example, the width L1 of the first opening K1 is greater than the width L1 'of the second opening K2, and the length L2 of the first opening K1 is greater than the length L2' of the second opening K2, accordingly, the width of the pad S corresponding to the first opening K1 is greater than the width of the pad S corresponding to the second opening K2, and the length of the pad S corresponding to the first opening K1 is greater than the length of the pad S corresponding to the second opening K2.

By setting the width L1 of the first opening K1 to be greater than the width L1 'of the second opening K2, and the length L2 of the first opening K1 to be greater than the length L2' of the second opening K2, the area of the pad S corresponding to the first opening K1 is greater than the area of the pad S corresponding to the second opening K2, so that the amount of the conductive portions T which can be filled by the pad S corresponding to the first opening K1 is increased, the thickness of the conductive portion T corresponding to the first opening K1 is increased, and it is ensured that in the case that the middle of the connector H is arched, the pins P can be completely wrapped by the conductive portions T, so that the problem of insufficient solder is avoided, and the product yield and the service life of the display device 100 are improved.

As shown in fig. 7, in some embodiments, the at least one first opening K1 is arranged in mirror symmetry along the first direction X, wherein the axis of symmetry extends along the second direction Y. Illustratively, the center line Qh of the pad region Q is taken as an axis of symmetry, i.e., the at least one first opening K1 is mirror-symmetrical about the center line Qh of the pad region Q.

As shown in fig. 7, in some embodiments, the at least one first opening K1 is equal in size along the first direction X and the at least one first opening K1 is equal in size along the second direction Y. The plurality of second openings K2 are equal in size in the first direction X, and the plurality of second openings K2 are equal in size in the second direction Y.

Illustratively, the at least one first opening K1 has the same shape and the same size, and the plurality of second openings K2 has the same shape and the same size.

As shown in fig. 7, the pad region Q illustratively includes a first sub-region Q1, and two second sub-regions Q2 disposed on both sides of the first sub-region Q1 along the first direction X, and a center line of the first sub-region Q1 along the second direction Y coincides with the reference line Qh.

At least one first opening K1 is provided in the first sub-area Q1, and at least one second opening K2 is provided in the second sub-area Q2. That is, the area of the opening K in the first sub-area Q1 is larger than the area of the opening K in the second sub-area Q2. Therefore, the quantity of the conductive parts T which can be filled in the pad S in the middle of the pad area Q (namely the first sub-area Q1) is increased, the thickness of the conductive parts T corresponding to the pad S in the middle of the pad area Q is increased, and therefore the pin P can be completely wrapped by the conductive parts T under the condition that the middle of the connector H is arched, the problem of insufficient soldering is avoided, and the product yield and the service life of the display device 100 are improved.

Illustratively, the dimensions of the first sub-zone Q1 and the second sub-zone Q2 in the first direction X are substantially equal, i.e. the number of first openings K1 is substantially half of the number of second openings K2, the number of openings K having a larger area occupying substantially one third of the number of total openings K.

Illustratively, the ratio of the size of the first sub-area Q1 and the second sub-area Q2 in the first direction X is designed according to the ratio of the number of the arched pins P, for example, the number of the arched pins P occupies one third of the total number of the pins P, and accordingly, the size of the first sub-area Q1 in the first direction X occupies approximately one third of the size of the pad area Q in the first direction X, that is, the number of the first openings K1 with a larger area occupies approximately one third of the total number of the openings K.

The pad area Q is divided into a first sub-area Q1 and two second sub-areas Q2 which are respectively arranged at two sides of the first sub-area Q1, so that the number of the first openings K1 is controlled, the number of the pads S with larger size approximately corresponds to the number of the arched pins P, namely the number of the conductive parts T with thickened thickness approximately corresponds to the number of the arched pins P, and the problem that the partial pins P still have insufficient solder joints due to the fact that the number of the conductive parts T with thickened thickness is small is solved.

In addition, after research, the inventors of the present disclosure found that the leads P extend into the conductive portion T too deeply, for example, in addition to the soldering portion P2 extending into the conductive portion T, a part of the trunk portion P1 also extends into the conductive portion T, which may press the material of the conductive portion T to cause material overflow of the conductive portion T, and the overflow conductive material may easily cause conduction between components or signal lines, for example, between two adjacent leads P, which may cause signal crosstalk or direct short circuit of the signal lines.

By controlling the number of the first openings K1, the number of the conductive parts T with the thickened thickness is approximately equal to the number of the arched pins P, and the problem that the conductive material of the conductive parts T overflows to cause short circuit due to the large number of the conductive parts T with the thickened thickness is solved.

In some embodiments, an area of an orthogonal projection of the opening K on the substrate 10 is gradually increased in the first direction X and in a direction near the center line Qh of the pad region Q. Wherein, gradually increasing includes increasing sequentially or increasing stepwise.

Illustratively, the area of the orthographic projection of the first opening K1 on the substrate 10 is gradually increased along the first direction X and in a direction close to the symmetry axis (i.e., the center line Qh of the pad region Q). For example, referring to fig. 9, the width L1 of the first opening K1 is gradually increased, and/or the length L2 of the first opening K1 is gradually increased.

Illustratively, in the first direction X and the direction close to the at least one first opening K1, the area of the orthographic projection of the second opening K2 on the substrate 10 gradually increases or increases in a stepwise manner. For example, referring to fig. 9, the width L1 'of the second opening K2 is gradually increased and/or the length L2' of the second opening K2 is gradually increased in a direction along the first direction X and near the symmetry axis (i.e., the center line Qh of the pad region Q).

The area of the orthographic projection of the opening K on the substrate 10, which is gradually close to the center line Qh of the pad area Q, is gradually increased, so that the thickness change of the conductive part T corresponds to the arching degree of the pins P, the thickness of the conductive part T just can wrap the welding part P2 of the corresponding pins P, the problem that the partial pins P are still subjected to false welding due to the fact that the thickness of the conductive part T is too thin is avoided, and meanwhile, the problem that the conductive material of the conductive part T overflows to cause short circuit due to the fact that the thickness of the conductive part T is too thick is avoided.

As shown in fig. 7, in some embodiments, the centers Kh of the plurality of openings K are all located on the same straight line Kh' extending in the first direction X.

Illustratively, the plurality of openings K are provided in a plurality of rows, and the centers of the plurality of openings K of each row are located on the same straight line extending in the first direction X.

The centers of the openings K are arranged on the same straight line, so that the position of the welding disc S is matched with the position of the pin P of the connector H, and the welding with the pin P is convenient to realize.

In some embodiments, the first opening K1 has a dimension along the first direction X of 0.17cm to 0.20cm, and the first opening K1 has a dimension along the second direction Y of 0.48cm to 0.49 cm.

Illustratively, the width L1 of the first opening K1 is 0.17cm to 0.20cm, the length L2 of the first opening K1 is 0.48cm to 0.49cm, for example, the width L1 of the first opening K1 is 0.17cm, and the length L2 of the first opening K1 is 0.49 cm.

Illustratively, the width L1 of the first opening K1 gradually increases along the first direction X and in a direction close to the center line Qh of the pad region Q, and for example, the width L1 of the first opening K1 varies to 0.17cm, 0.1705cm, 0.171cm, 0.1715cm, 0.172cm, 0.174cm, 0.177cm, 0.20 cm.

Illustratively, the length L2 of the first opening K1 gradually increases in the first direction X and in a direction near the center line Qh of the pad area Q, and for example, the length L2 of the first opening K1 varies to 0.48cm, 0.481cm, 0.4815cm, 0.482cm, 0.483cm, 0.485cm, 0.487cm, 0.490 cm.

Through the numerical range of the size that sets up first opening K1, the size of the area of effective control pad S to control conductive part T ' S thickness is moderate, thereby when solving pin P and appearing the rosin joint problem, guarantees that conductive part T ' S conducting material can not spill over, avoids display panel 200 ' S circuit to take place the short circuit.

Illustratively, the width L1 'of the second opening K2 is 0.15cm to 0.16cm, the length L2' of the second opening K2 is 0.47cm to 0.48cm, for example, the width L1 'of the second opening K2 is 0.16cm, and the length L2' of the second opening K2 is 0.475 cm.

Through the numerical range of the size that sets up second opening K2, the size of the area of effective control pad S to control conductive part T 'S thickness is moderate, thereby when solving pin P and appearing the rosin joint problem, guarantees that conductive part T' S conducting material can not spill over, avoids the circuit to take place the short circuit.

In some embodiments, the ratio of the number of first openings K1 to the number of second openings K2 is 1: 0.6-1: 2.0. illustratively, the ratio of the number of the first openings K1 to the number of the second openings K2 is 1: 0.6. for example, among the plurality of openings K in the same row, the number of the first openings K1 is 8, the number of the second openings K2 is 12, and the plurality of openings K are uniformly distributed.

Through the research of the inventors of the present disclosure, it was found that by setting the ratio of the number of the first openings K1 to the number of the second openings K2 to 1: 0.6-1: 2.0, the problem of insufficient soldering of the pin P can be solved, and meanwhile, the conductive material of the conductive part T can not overflow, and short circuit of the circuit is avoided.

In some embodiments, the dimension of the second opening K2 along the first direction X is 0.15cm to 0.16cm, and the dimension of the second opening K2 along the second direction Y is 0.47cm to 0.48 cm.

As shown in fig. 10, in some embodiments, the flexible printed circuit board 300 further includes a conductive film T 'disposed on an inner wall formed by the opening K formed in the protection layer 30, and the conductive film T' is electrically connected to the conductive layer 20.

Illustratively, the material of the conductive film T' is the same as that of the conductive layer 20.

The conductive film T 'is disposed inside the opening K, which can effectively increase the contact area between the conductive portion T and the conductive material (including the conductive layer 20 and the conductive film T'), thereby enhancing the conductive effect and improving the welding strength between the conductive portion T and the flexible printed circuit board 300.

As shown in fig. 11, in some embodiments, the flexible printed circuit board 300 further includes a shielding layer 40 disposed on a side of the protection layer 30 away from the substrate 10, wherein the shielding layer 40 is configured to shield external signal interference. The shielding layer 40 is provided with a plurality of through holes K' communicating with the openings K to expose the pads S.

Illustratively, the shielding layer 40 may show interference of high frequency signals on other components of the device 100 with signals on the flexible wiring board 300.

Illustratively, the material of the shielding layer 40 may be a metal, for example, the material of the shielding layer 40 may be copper.

As shown in fig. 11, the substrate 10 is provided with a shielding layer 40 on both sides thereof close to and away from the driving circuit board 400, for example.

The above description is only for the specific embodiments of the present disclosure, but the scope of the present disclosure is not limited thereto, and any person skilled in the art will appreciate that changes or substitutions within the technical scope of the present disclosure are included in the scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. A flexible wiring board, comprising:

a substrate;

a conductive layer disposed on the substrate;

the protective layer is arranged on one side, away from the substrate, of the conductive layer, the protective layer is provided with a plurality of openings, and the part, exposed by the openings, of the conductive layer serves as a bonding pad;

2. The flexible wiring board of claim 1, wherein the opening is elongated;

the size of the first opening along the first direction is larger than that of the second opening along the first direction; and/or the presence of a gas in the gas,

the size of the first opening along the second direction is larger than that of the second opening along the second direction.

3. The flexible wiring board of claim 1, wherein the at least one first opening is arranged in mirror symmetry along the first direction, and wherein an axis of symmetry extends along the second direction.

4. The flexible wiring board of claim 1, wherein the at least one first opening is equal in size in a first direction and the at least one first opening is equal in size in a second direction;

the plurality of second openings are equal in size in the first direction, and the plurality of second openings are equal in size in the second direction.

5. The flexible wiring board of claim 1, wherein an area of an orthographic projection of the second opening on the substrate is gradually increased along the first direction and in a direction adjacent to the at least one first opening.

6. The flexible wiring board of claim 3, wherein an area of an orthographic projection of the first opening on the substrate is gradually increased along the first direction and in a direction close to the axis of symmetry.

7. The flexible wiring board of claim 1, wherein the centers of the plurality of openings are all located on a same straight line extending in the first direction.

8. The flexible wiring board of claim 1, wherein the first opening has a dimension in the first direction of 0.17cm to 0.20cm, and the first opening has a dimension in the second direction of 0.48cm to 0.49 cm.

9. The flexible wiring board of claim 1, wherein the second opening has a dimension in the first direction of 0.15cm to 0.16cm, and the second opening has a dimension in the second direction of 0.47cm to 0.48 cm.

10. The flexible wiring board of claim 1, wherein the ratio of the number of first openings to the number of second openings is 1: 0.6-1: 2.0.

11. the flexible printed circuit according to any one of claims 1 to 10, further comprising a conductive film disposed on an inner wall formed by an opening formed in the protective layer, wherein the conductive film is electrically connected to the conductive layer.

12. The flexible circuit board according to any one of claims 1 to 10, further comprising a shielding layer disposed on a side of the protective layer away from the substrate, wherein the shielding layer is configured to shield external signal interference;

the shielding layer is provided with a plurality of through holes, and the through holes are communicated with the openings so as to expose the bonding pads.

13. A display device, comprising:

a flexible wiring board according to any one of claims 1 to 12;

a driver circuit board comprising a connector, the connector comprising a plurality of pins;

the conductive parts are arranged between the flexible circuit board and the driving circuit board, at least part of the conductive parts are positioned in the opening of the flexible circuit board and are electrically connected with the bonding pads at the opening, and the conductive parts are also electrically connected with the pins.

14. The display device according to claim 13, wherein the plurality of conductive portions are arranged in a first direction;

the plurality of conductive parts comprise at least one first conductive part and a plurality of second conductive parts, the plurality of second conductive parts are uniformly arranged on two sides of the at least one first conductive part, and the volume of the first conductive part is larger than that of the second conductive part.

15. The display device according to claim 14, wherein a dimension of the first conductive portion in a thickness direction perpendicular to a substrate of the flexible circuit board is larger than a dimension of the second conductive portion in the thickness direction perpendicular to the substrate of the flexible circuit board.