CN215991335U - Flexible circuit board and display module - Google Patents

Abstract

The utility model relates to a flexible circuit board, which is used for connecting a display panel, comprises a substrate and comprises: a body region; one end of the main body area is provided with a first binding area, and the first binding area is provided with a bonding pad; the first binding region and the body region are provided with a transition region therebetween, the transition region is provided with a transition structure, wherein the pad and the transition structure are both located on the first surface of the substrate, and the thickness of the transition structure in the direction perpendicular to the substrate is smaller than the thickness of the pad in the direction perpendicular to the substrate. The utility model also relates to a display module.

Description

Flexible circuit board and display module

Technical Field

The utility model relates to the technical field of display product manufacturing, in particular to a flexible circuit board and a display module.

Background

With the continuous development of AMOLED (Active Matrix/Organic Light Emitting Diode), flexible display and full screen display will certainly be the development trend in the coming years, but the development of new technology will inevitably bring new technical challenges. The problems encountered by folding mobile phones and folding notebooks are unprecedented as the folding products are larger and larger. As the size of the folded product increases, the resolution will also increase, and multiple FPC or COF (chip on film) Bonding necessarily tends to be a trend, but as the Bonding area increases, the risk of short circuit in the Bonding area also increases exponentially.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the utility model provides a flexible circuit board and a display module, which solve the problem that short circuit is easy to occur in binding connection of the flexible circuit board.

In order to achieve the purpose, the embodiment of the utility model adopts the technical scheme that: a flexible wiring board for connecting a display panel, the flexible wiring board including a substrate, comprising:

a body region;

one end of the main body area is provided with a first binding area, and the first binding area is provided with a bonding pad;

a transition region between the first binding region and the body region, the transition region being provided with a transition structure, wherein,

the pad and the transition structure are both located on the first surface of the base material, and the thickness of the transition structure in the direction perpendicular to the base material is smaller than the thickness of the pad in the direction perpendicular to the base material.

Optionally, along a direction away from the first surface of the substrate, the main body region is sequentially provided with a first conductive layer and a first cover layer, the pad includes a second conductive layer and a third conductive layer which are sequentially provided, and the transition structure includes a transition film layer disposed on the substrate;

the thickness of the second conductive layer in the direction perpendicular to the substrate is the same as the thickness of the transition film layer in the direction perpendicular to the substrate.

Optionally, the substrate has a second surface opposite to the first surface, a sixth conductive layer is disposed on the second surface, the pad is connected to the sixth conductive layer through a via hole disposed on the substrate, and the sixth conductive layer is connected to the first conductive layer through a via hole disposed on the substrate.

Optionally, along a direction away from the first surface of the substrate, the main body region is sequentially provided with a first conductive layer and a first cover layer, the pad includes a second conductive layer and a third conductive layer which are sequentially provided, and the transition structure includes a fourth conductive layer and a transition film layer;

the first conductive layer, the second conductive layer and the fourth conductive layer are arranged on the same layer.

Optionally, the material of the fourth conductive layer includes copper.

Optionally, along a direction away from the first surface of the substrate, the main body region is sequentially provided with a first conductive layer and a first covering layer, the pad includes a second conductive layer, a fifth conductive layer and a third conductive layer, which are sequentially provided, and the transition structure includes a fourth conductive layer and a transition film layer;

the first conductive layer, the second conductive layer and the fourth conductive layer are arranged on the same layer.

Optionally, the material of the fourth conductive layer and the material of the fifth conductive layer both include copper.

Optionally, the material of the first conductive layer and the material of the second conductive layer both include copper, and the material of the third conductive layer includes at least one of gold, nickel, and gold-nickel alloy.

Optionally, the thickness of the transition structure is 10-12um, and the difference between the thickness of the pad and the thickness of the transition structure is 8-10 um.

Optionally, a sixth conductive layer is disposed on a second surface of the substrate opposite to the first surface, the sixth conductive layer is located on the body region, and a second cover layer is disposed on a side of the sixth conductive layer away from the substrate.

Optionally, in the first bonding region, a reinforcing layer is disposed on the second surface of the substrate.

The embodiment of the utility model also provides a display module, which comprises a display panel and the flexible circuit board, wherein the display panel comprises a display area, a second binding area and an edge area which are adjacently arranged;

the second binding region is provided with a bonding pad which is bound and connected with the bonding pad of the flexible circuit board, and at least part of the orthographic projection of the transition structure on the display panel is positioned on the marginal region.

The utility model has the beneficial effects that: the transition structure is perpendicular to the thickness of the substrate in the direction is less than the pad is perpendicular to the thickness of the substrate in the direction, when the flexible circuit board is bound with the display panel and connected, the transition structure enters the marginal area of the display panel, the pad is prevented from being exposed, the binding connection of the flexible circuit board and the display panel is not influenced, and the problem of short circuit between the flexible circuit board and the display panel is solved.

Drawings

Fig. 1 is a schematic view showing a state before a flexible printed circuit board and a display panel are bound and connected in the related art;

FIG. 2 is a first schematic diagram illustrating a state before a flexible printed circuit board and a display panel are bound and connected according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a first embodiment of a flexible printed circuit board stack structure;

FIG. 4 is a schematic diagram of a second embodiment of a flexible printed circuit board stacked structure according to the present invention;

FIG. 5 is a schematic diagram of a third embodiment of a flexible printed circuit board stack structure according to the present invention;

FIG. 6 is a schematic diagram of a display module according to an embodiment of the utility model;

fig. 7 is a schematic diagram showing a second state before the flexible circuit board and the display panel are bound and connected in the embodiment of the utility model.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the utility model, are within the scope of the utility model.

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

Referring to fig. 1, the flexible printed circuit board includes a body region, a first bonding region is disposed at one end of the body region, a transition region is disposed between the first bonding region and the body region, the first bonding region is disposed with a first pad 10, the transition region is disposed with a transition structure 20, in order to prevent the first pad 10 from breaking when bending, the transition structure covers a portion of the first pad 10, and an end of the transition structure 20 bordering the first pad 10 is disposed in a wavy shape, in order to ensure flatness of the first pad 10, the transition structure 20 is located outside the display panel, so that a portion of the pad 10 is necessarily exposed with respect to the display panel, referring to fig. 1, a distance b between one end of the transition structure 20 close to the first pad 10 and an edge of the display panel is about 0.1mm, and a distance a between the edge of the display panel and the second pad 20 is about 0.2mm, these dimensions are critical dimensions that lead to undesirable results. After analysis, it is confirmed that carbon residue exists at the edge when the display panel is cut, and a carbonized region is formed (the carbonized region is located in the edge region with the width a in the first direction), the carbonized region contains carbide (the carbide is short for short, the carbide contains display panel fragments, and the display panel fragments contain ITO fragments), when the flexible circuit board is bound and connected, the carbide is pressed between the first bonding pad 10 of the flexible circuit board and the second bonding pad 30 of the display panel, the existence of the carbide causes short circuit between two signal lines, and the short-circuited signal lines are random, so that defects such as a dark line or an unlighted line occur randomly in the bound region.

In view of the above technical problems, the present embodiment provides a flexible printed circuit board for connecting a display panel, the flexible printed circuit board including a substrate, including:

a body region 101;

a first bonding region 103 is arranged at one end of the body region 101, and a pad 10 is arranged in the first bonding region 103;

between the first binding region 103 and the body region 101, there is a transition region 102, which transition region 102 is provided with a transition structure, wherein,

the pad 10 and the transition structure are both located on the first surface 106 of the substrate 100;

and the thickness of the transition structure in the direction perpendicular to the substrate 100 is smaller than the thickness of the pad 10 in the direction perpendicular to the substrate 100.

By adopting the technical scheme, because the thickness of the transition structure in the direction perpendicular to the substrate 100 is smaller than the thickness of the pad 10 in the direction perpendicular to the substrate 100, when the flexible circuit board is bound and connected with the display panel, the transition structure enters the edge region of the display panel, namely, at least part of the orthographic projection of the transition structure on the display panel is positioned in the edge region of the display panel, referring to fig. 2, the pad 10 is prevented from being exposed, the pad 10 is protected, the pad 10 is prevented from being exposed and contacted with the carbonization region (the carbonization region is positioned in the edge region) of the display panel, the problem of easy short circuit between the flexible circuit board and the display panel is solved, and because the thickness of the transition structure in the direction perpendicular to the substrate 100 is smaller than the thickness of the pad 10 in the direction perpendicular to the substrate 100, even if the transition structure extends into the space between the display panel and the flexible circuit board, the flatness of the binding area can not be influenced, and the binding connection between the flexible circuit board and the display panel can not be influenced.

In this embodiment, the transition structure with the tip that pad 10 is bordered is wavy setting, has improved the anti performance of buckling of pad 10 to avoid causing the copper line fracture because the buckling of pad 10, influence the normal use of product.

The transition structure and the specific structural form of the pad 10 may be various, as long as the thickness of the transition structure in the direction perpendicular to the substrate 100 is smaller than the thickness of the pad 10 in the direction perpendicular to the substrate 100, when the display panel is bonded, at least a part of the orthographic projection of the transition structure on the display panel is located in the edge region of the display panel (at least a part of the orthographic projection coincides with the carbonization region), and several specific structural forms of the flexible printed circuit board in this embodiment are specifically described below.

Referring to fig. 3, in some embodiments of the present embodiment, the body region 101 is sequentially disposed with a first conductive layer 31 and a first cover layer 40 along a direction away from the first surface 106 of the substrate 100, the pad 10 includes a second conductive layer 11 and a third conductive layer 13 sequentially disposed, and the transition structure includes a transition film layer 21 disposed on the substrate 100;

the thickness of the second conductive layer 11 in the direction perpendicular to the substrate 100 is the same as the thickness of the transition film layer 21 in the direction perpendicular to the substrate 100;

the substrate 100 has a second surface 107 disposed opposite to the first surface 106, a sixth conductive layer 50 is disposed on the second surface 107, the pad 10 is connected to the sixth conductive layer 50 through a via (a first via 104 in fig. 3) disposed on the substrate 100, and the sixth conductive layer 50 is connected to the first conductive layer 31 through a via (a second via 105 in fig. 3) disposed on the substrate 100.

In the above scheme, the thickness of the second conductive layer 11 in the direction perpendicular to the substrate 100 is the same as the thickness of the transition film layer 21 in the direction perpendicular to the substrate 100, and then, after the third conductive layer 13 is disposed on the second conductive layer 11, the thickness of the pad 10 in the direction perpendicular to the substrate 100 is greater than the thickness of the transition structure in the direction perpendicular to the substrate 100.

In some embodiments of the present embodiment, the material of the first conductive layer 31 and the second conductive layer 11 includes copper, and the material of the third conductive layer 13 includes at least one of gold, nickel, and gold-nickel alloy, but not limited thereto.

The third conductive layer 13 protects the second conductive layer 11, and prevents the second conductive layer 11 from being exposed and oxidized.

In some embodiments of the present embodiment, the thickness of the transition film layer 21 is 10-12um, but not limited thereto.

In this embodiment, the thickness of the third conductive layer 13 may be 5-10um, so as to ensure that when the flexible printed circuit board is bound and connected with the display panel, the pad 10 does not contact with the edge region of the display panel, and the transition structure does not contact with the edge region of the display panel.

Referring to fig. 4 and 7, in some embodiments of the present embodiment, the body region 101 is sequentially disposed with a first conductive layer 31 and a first cover layer 40 along a direction away from the first surface 106 of the substrate 100, the pad 10 includes a second conductive layer 11 and a third conductive layer 13 sequentially disposed, and the transition structure includes a fourth conductive layer 22 and a transition film layer 21;

the first conductive layer 31, the second conductive layer 11, and the fourth conductive layer 22 are disposed in the same layer.

The first conductive layer 31, the second conductive layer 11, and the fourth conductive layer 22 are disposed on the same layer and integrally disposed on the first surface 106 of the substrate 100, and are integrally formed, so as to simplify the process steps, in this embodiment, the thickness of the transition film layer 21 in the direction perpendicular to the substrate 100 is smaller than the thickness of the third conductive layer 13 in the direction perpendicular to the substrate 100, so that the thickness of the pad 10 in the direction perpendicular to the substrate 100 is larger than the thickness of the transition structure in the direction perpendicular to the substrate 100.

In a specific implementation manner of this embodiment, the thickness of the transition film layer 21 is 10-12um, and the thickness of the third conductive layer 13 is 15-20um, but not limited thereto.

In a specific implementation manner of this embodiment, the materials of the first conductive layer 31, the second conductive layer 11, and the fourth conductive layer 22 all include copper, and the material of the third conductive layer 13 includes at least one of gold, nickel, and gold-nickel alloy, but not limited thereto.

Referring to fig. 5, in some embodiments of the present embodiment, the body region 101 is sequentially disposed with a first conductive layer 31 and a first cover layer 40 along a direction away from the first surface 106 of the substrate 100, the pad 10 includes a second conductive layer 11, a fifth conductive layer 12, and a third conductive layer 13 sequentially disposed, and the transition structure includes a fourth conductive layer 22 and a transition film layer 21;

wherein the first conductive layer 31, the second conductive layer 11 and the fourth conductive layer 22 are disposed in the same layer.

Compared with the structure of the flexible circuit board shown in fig. 4, the pad 10 shown in fig. 5 adopts a three-layer structure, since the third conductive layer 13 is made of gold, nickel or gold-nickel alloy, etc., and mainly functions to prevent oxidation of copper forming the second conductive layer 11, so the thickness of the third conductive layer 13 in the direction perpendicular to the substrate 100 is too thick, which affects the quality of the bonding connection, the pad 10 shown in fig. 5 adopts a three-layer structure, and compared with the pad 10 shown in fig. 4, a fifth conductive layer 12 is additionally arranged between the second conductive layer 11 and the third conductive layer 13, the fifth conductive layer 12 is formed on the second conductive layer 11 by copper plating, and the arrangement of the fifth conductive layer 12 can ensure that the thickness of the pad 10 in the direction perpendicular to the substrate 100 is greater than the thickness of the transition structure in the direction perpendicular to the substrate 100, and the thickness of the third conductive layer 13 is reduced, so that the quality of binding connection is ensured.

In a specific implementation manner of this embodiment, the thickness of the transition structure is 10-12um, and a difference between the thickness of the pad 10 and the thickness of the transition structure is 8-10um, but not limited thereto.

The thickness of transition film layer 21, third conducting layer 13 and the thickness of fifth conducting layer 12 can be set according to actual need, the one side that substrate 100 was kept away from to fifth conducting layer 12 with transition film layer 21 keeps away from the one side of substrate 100 is flushed, also can not be flushed, namely the thickness of fifth conducting layer 12 in the direction that is perpendicular to substrate 100 can be equal to or not equal to the thickness of transition film layer 21 in the direction that is perpendicular to substrate 100, in an embodiment, the thickness of second conducting layer 11 can be 10-12um, the thickness of fifth conducting layer 12 can be 4-5 um.

In some embodiments of the present embodiment, the materials of the first conductive layer 31, the second conductive layer 11, the fourth conductive layer 22, and the fifth conductive layer 12 all include copper, and the material of the third conductive layer 13 includes at least one of gold, nickel, and gold-nickel alloy, but not limited thereto.

Referring to fig. 4 and fig. 5, in some embodiments of the present embodiment, a sixth conductive layer 50 is disposed on a second surface 107 of the substrate 100 opposite to the first surface 106, the sixth conductive layer 50 is located on the body region 101, and a second covering layer 60 is disposed on a side of the sixth conductive layer 50 away from the substrate 100.

In some embodiments of the present embodiment, a reinforcing layer 70 is disposed on the second surface 107 of the substrate 100 in the first bonding region 103.

The reinforcing layer 70 enhances the strength of the bonding pad 10 and prevents the bonding pad 10 from breaking.

The second surface 107 of the substrate 100 and the transition region 102 are not provided with other structures, that is, the second surface 107, the reinforcing layer 70 and the sixth conductive layer 50 are provided at intervals, and the transition region 102 is provided with a transition structure only on the first surface 106 of the substrate 100, so as to facilitate bending of the flexible printed circuit board.

In some embodiments of this embodiment, the first cover layer 40 is connected to the first conductive layer 31 through an adhesive layer 200, the second cover layer 60 is connected to the sixth conductive layer 50 through an adhesive layer 200, the reinforcing layer 70 is connected to the substrate 100 through an adhesive layer 200, and the adhesive layer 200 may be a double-sided adhesive, but is not limited thereto.

In some embodiments of the present embodiment, the first cover layer 40 and the second cover layer 60 are polyimide film layers, but not limited thereto.

In some embodiments of the present embodiment, the stiffening layer 70 may be a polyimide film layer, but is not limited thereto.

Referring to fig. 2 and fig. 7, the present embodiment further provides a display module, which includes a display panel 2 and the flexible circuit board 1, where the display panel 2 includes a display area, and a second binding area and an edge area 21 sequentially disposed on one side of the display area along a first direction;

the second binding region is provided with a bonding pad 10 bound and connected with the bonding pad 10 of the flexible circuit board, and at least part of the orthographic projection of the transition structure on the display panel is positioned on the edge region 21.

Referring to fig. 2 and 7 (only the structure of the first surface 106 of the substrate is shown in fig. 2 and 7), since the thickness of the bonding pad 10 in the direction perpendicular to the substrate 100 is greater than the thickness of the transition structure in the direction perpendicular to the substrate 100, when the flexible printed circuit board 1 is bonded to the display panel 2, at least a portion of the transition structure 20 is orthographically projected on the display panel 2 and is located on the edge region 21, so that the occurrence of short circuit between the flexible printed circuit board 1 and the display panel 2 caused by carbide of the edge region 21 can be avoided.

Fig. 6 is a schematic structural diagram of a large-sized product in an AMOLED product, where the display panel 2 is rectangular, the long side direction of the display panel is a Source driving direction, the second bonding region of the display panel 2 has a plurality of Source driving ICs 201 distributed along the long side direction thereof, a plurality of Source wires (data lines) connected to the plurality of Source driving ICs 201 are distributed in the display panel 2, and fig. 6 is only a schematic diagram, where each Source driving IC 201 is connected to a plurality of data lines, and the display module further includes a plurality of flexible circuit boards 1 bonded to the plurality of Source driving ICs 201 in a one-to-one correspondence manner.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the utility model, and these modifications and improvements are also considered to be within the scope of the utility model.

Claims (12)

1. A flexible wiring board for connecting a display panel, the flexible wiring board including a substrate, comprising:

a body region;

one end of the main body area is provided with a first binding area, and the first binding area is provided with a bonding pad;

a transition region between the first binding region and the body region, the transition region being provided with a transition structure, wherein,

the pad and the transition structure are both located on the first surface of the base material, and the thickness of the transition structure in the direction perpendicular to the base material is smaller than the thickness of the pad in the direction perpendicular to the base material.

2. The flexible circuit board of claim 1, wherein the main body region is sequentially provided with a first conductive layer and a first cover layer along a direction away from the first surface of the substrate, the pad comprises a second conductive layer and a third conductive layer sequentially provided, and the transition structure comprises a transition film layer provided on the substrate;

the thickness of the second conductive layer in the direction perpendicular to the substrate is the same as the thickness of the transition film layer in the direction perpendicular to the substrate.

3. The flexible wiring board of claim 2, wherein the substrate has a second surface disposed opposite the first surface, wherein a sixth conductive layer is disposed on the second surface, wherein the bonding pad is connected to the sixth conductive layer through a via disposed on the substrate, and wherein the sixth conductive layer is connected to the first conductive layer through a via disposed on the substrate.

4. The flexible wiring board of claim 1, wherein the main body region is sequentially provided with a first conductive layer and a first cover layer in a direction away from the first surface of the substrate, the pad comprises a second conductive layer and a third conductive layer which are sequentially provided, and the transition structure comprises a fourth conductive layer and a transition film layer;

the first conductive layer, the second conductive layer and the fourth conductive layer are arranged on the same layer.

5. The flexible wiring board of claim 4, wherein the material of the fourth conductive layer comprises copper.

6. The flexible wiring board of claim 1, wherein the main body region is sequentially provided with a first conductive layer and a first cover layer in a direction away from the first surface of the substrate, the pad comprises a second conductive layer, a fifth conductive layer and a third conductive layer which are sequentially provided, and the transition structure comprises a fourth conductive layer and a transition film layer;

the first conductive layer, the second conductive layer and the fourth conductive layer are arranged on the same layer.

7. The flexible wiring board of claim 6, wherein the material of the fourth conductive layer and the fifth conductive layer each comprises copper.

8. The flexible wiring board of any of claims 2-6, wherein the material of the first conductive layer and the second conductive layer each comprise copper, and the material of the third conductive layer comprises at least one of gold, nickel, and gold-nickel alloy.

9. The flexible wiring board of any of claims 2-6, wherein the thickness of the transition structure is 10-12um, and the difference between the thickness of the bonding pad and the thickness of the transition structure is 8-10 um.

10. The flexible circuit board of any one of claims 1-6, wherein a sixth conductive layer is disposed on a second surface of the substrate opposite to the first surface, the sixth conductive layer is disposed on the body region, and a second cover layer is disposed on a side of the sixth conductive layer away from the substrate.

11. The flexible wiring board of claim 9, wherein a stiffening layer is disposed on the second surface of the substrate in the first bonding region.

12. A display module comprising a display panel and the flexible circuit board of any one of claims 1-11, wherein the display panel comprises a display area, a second binding area and an edge area which are adjacently arranged;

the second binding region is provided with a bonding pad which is bound and connected with the bonding pad of the flexible circuit board, and at least part of the orthographic projection of the transition structure on the display panel is positioned on the marginal region.

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