CN114205997A

CN114205997A - Flexible circuit board and display module

Info

Publication number: CN114205997A
Application number: CN202111613219.5A
Authority: CN
Inventors: 胡洋
Original assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co Ltd
Current assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co Ltd
Priority date: 2021-12-27
Filing date: 2021-12-27
Publication date: 2022-03-18
Anticipated expiration: 2041-12-27
Also published as: CN114205997B

Abstract

The invention provides a flexible circuit board and a display module. The flexible circuit board comprises a circuit layer, a shielding layer, an adhesive layer and a conductive unit. At least one groove is arranged on one surface of the circuit layer. The shielding layer is pasted and covered on the surface of the circuit layer, which is provided with the groove, through the pasting glue layer. The conductive unit is arranged in the groove and penetrates through the adhesive layer to be electrically connected with the shielding layer.

Description

Flexible circuit board and display module

Technical Field

The invention relates to the field of display equipment, in particular to a flexible circuit board and a display module.

Background

With the development of mobile phones, while the technology is developing, the cost problem becomes another difficult problem which plagues the screen manufacturing industry, wherein FPCB (Flexible Printed Circuit Board) occupies a significant part of the cost composition of the product, and the existing design usually adopts a whole-surface conductive double-sided tape, and the copper-exposed area is filled with the conductive tape so as to eliminate the step difference. However, the whole surface is coated with the conductive double-sided adhesive tape, so that the production cost of the flexible circuit board is greatly increased.

Disclosure of Invention

The invention aims to provide a flexible circuit board and a display module to solve the technical problem of high production cost in the prior art.

In order to achieve the above object, the present invention provides a flexible circuit board, which includes a circuit layer, a shielding layer, an adhesive layer, and a conductive unit. At least one groove is arranged on one surface of the circuit layer. The shielding layer is attached to one surface, provided with the groove, of the circuit layer. The adhesive layer is arranged between the shielding layer and the circuit layer. The conductive unit fills the groove and penetrates through the adhesive layer to be electrically connected with the shielding layer.

Furthermore, the adhesive layer is provided with at least one through hole, the through hole corresponds to the groove, and the conductive unit fills the through hole.

Further, the orthographic projection of the through hole on the circuit layer is coincident with the orthographic projection of the groove on the circuit layer.

Furthermore, a surface of the conductive unit far away from the circuit layer and a surface of the adhesive layer far away from the circuit layer are located on the same plane

Further, the conductive unit comprises a metal layer, and the metal layer is arranged in the groove.

Furthermore, the conductive unit further comprises a conductive adhesive layer, and the conductive adhesive layer is arranged on the metal layer and a surface of the metal layer facing the shielding layer.

Further, the thickness of the metal layer is less than or equal to 150 micrometers.

Further, the metal layer contains copper.

Further, the depth of the groove is smaller than the thickness of the conductive unit.

The invention further provides a display module, and the display module comprises the flexible circuit board.

The invention has the advantages that: according to the flexible circuit board and the display module, the conductive function and the fixing function of the conductive double-sided adhesive tape in the prior art are separated, the shielding layer is fixed by using the common adhesive layer, and the conductive unit penetrates through the adhesive layer and is directly and electrically connected with the shielding layer, so that the use area of the conductive adhesive is greatly reduced, and the production cost and the maintenance cost of the display module are further reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a plan view of the back surface of a flexible circuit board in embodiment 1 of the present invention;

FIG. 2 is a schematic cross-sectional view taken along line AA' of FIG. 1;

fig. 3 is a plan view of the back surface of a flexible circuit board in embodiment 2 of the present invention;

FIG. 4 is a schematic cross-sectional view taken along line BB' in FIG. 3;

the components in the figures are represented as follows:

a flexible circuit board 1; a circuit layer 10;

a front face 11; a back side 12;

a groove 13; a conductive unit 20;

a metal layer 21; a conductive adhesive layer 22;

a shielding layer 30; a bonding layer 40;

a through hole 41.

Detailed Description

The preferred embodiments of the present invention will be described below with reference to the accompanying drawings, which are included to demonstrate that the invention can be practiced, and to provide those skilled in the art with a complete description of the invention so that the technical content thereof will be more clear and readily understood. The present invention may be embodied in many different forms of embodiments and should not be construed as limited to the embodiments set forth herein.

In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views. The size and thickness of each component shown in the drawings are arbitrarily illustrated, and the present invention is not limited to the size and thickness of each component. The thickness of the components may be exaggerated where appropriate in the figures to improve clarity.

Furthermore, the following description of the various embodiments of the invention refers to the accompanying drawings that illustrate specific embodiments of the invention, by which the invention may be practiced. Directional phrases used in this disclosure, such as, for example, "upper," "lower," "front," "rear," "left," "right," "inner," "outer," "side," and the like, refer only to the orientation of the appended drawings and are, therefore, used herein for better and clearer illustration and understanding of the invention, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

When certain components are described as being "on" another component, the components can be directly on the other component; there may also be an intermediate member disposed on the intermediate member and the intermediate member disposed on the other member. When an element is referred to as being "mounted to" or "connected to" another element, they may be directly "mounted to" or "connected to" the other element or indirectly "mounted to" or "connected to" the other element through an intermediate element.

Example 1

The embodiment of the invention provides a display module, which comprises a display panel and a chip on film, wherein the chip on film is arranged on the back 12 of the display panel and is electrically connected with a binding terminal in the display panel. The chip on film comprises a flexible circuit board 1 and an IC chip fixed on the flexible circuit board 1. The IC chip is connected with the display panel through the flexible circuit board 1 and transmits display signals to the display panel.

As shown in fig. 1-2, the flexible circuit board 1 includes a circuit layer 10, two conductive elements 20, a shielding layer 30, and a bonding layer 40.

The circuit layer 10 is provided with a plurality of signal traces, and has a front surface 11 and a back surface 12 opposite to the front surface 11. The IC chip is packaged on the front surface 11 of the circuit layer 10 and electrically connected to the signal traces in the circuit layer 10.

Two grooves 13 and a shielding layer 30 are provided on the back surface 12 of the circuit layer 10. Each groove 13 of the circuit layer 10 is provided with a conductive unit 20, and the conductive unit 20 is electrically connected to the shielding layer 30, so that static electricity and heat in the circuit layer 10 are conducted to the shielding layer 30, the shielding layer 30 plays a role in shielding signals, and the reliability of the display module is ensured.

The shielding layer 30 is made of an SCF (super Composite film) copper foil, and the SCF copper foil is formed by compounding foam, PI (Polyimide), and copper foil, and can play a good role in heat dissipation and protection.

The flexible circuit board 1 further includes a bonding layer 40. The adhesive layer 40 is located between the shielding layer 30 and the circuit layer 10, and is a common double-sided adhesive layer, and the shielding layer 30 is fixed on the back 12 of the circuit layer 10 through the adhesive layer 40. Two through holes 41 are formed in the adhesive layer 40, the through holes 41 penetrate through the adhesive layer 40 and correspond to the grooves 13, and the conductive unit 20 penetrates through the through holes 41 and is electrically connected with the shielding layer 30.

Specifically, an orthographic projection of the through hole 41 on the circuit layer 10 coincides with an orthographic projection of the groove 13 on the circuit layer 10. Moreover, the opening area of each through hole 41 on the adhesive layer 40 is larger than or equal to the opening area of the groove 13 on the circuit layer 10, that is, the aperture of the through hole 41 is larger than or equal to the diameter of the notch of the groove 13, so as to prevent the adhesive layer 40 from affecting the electrical connection between the conductive unit 20 and the shielding layer 30.

The conductive element 20 fills the recess 13 and the through hole 41 with a thickness equal to the sum of the depth of the recess 13 and the depth of the through hole 41. As shown in fig. 2, the conductive unit 20 includes a metal layer 21 and a conductive adhesive layer 22, and the metal layer 21 and the conductive adhesive layer 22 are stacked. The metal layer 21 is made of copper, and is disposed on the bottom of the groove 13. The conductive adhesive layer 22 is disposed on a surface of the metal layer 21 facing the shielding layer 30, and the metal layer 21 is electrically connected to the shielding layer 30 through the conductive adhesive layer 22.

Specifically, the thickness of the metal layer 21 is smaller than the depth of the groove 13. The conductive adhesive layer 22 fills the remaining space in the groove 13 and the through hole 41 in the adhesive layer 40, thereby achieving a conductive function between the metal layer 21 and the shielding layer 30. Moreover, a surface of the conductive adhesive layer 22 away from the circuit layer 10 and a surface of the adhesive layer 40 away from the circuit layer 10 are located on the same plane, so that a step difference between the metal layer 21 and the adhesive layer 40 is eliminated, a phenomenon of virtual adhesion of the shielding layer 30 is prevented, and the shielding layer 30 can be smoothly fixed on the back surface 12 of the circuit layer 10.

In the embodiment of the invention, the conductive double-sided adhesive layer in the prior art is replaced by the common adhesive layer so as to fix the shielding layer, and the conductive unit passes through the adhesive layer and is directly and electrically connected with the shielding layer so as to realize the conductive function of the conductive double-sided adhesive in the prior art, so that the conductive function and the fixing function of the conductive double-sided adhesive in the prior art are separated, the use area of the conductive adhesive is greatly reduced, and the production cost and the maintenance cost of the display module are further reduced.

Example 2

As shown in fig. 3-4, the flexible circuit board 1 includes a circuit layer 10, two conductive elements 20, a shielding layer 30, and a bonding layer 40.

The conductive element 20 fills the recess 13 and the through hole 41 with a thickness equal to the sum of the depth of the recess 13 and the depth of the through hole 41. As shown in fig. 4, the conductive element 20 is a metal layer 21 made of copper. One end of the metal layer 21 is disposed on the bottom of the groove 13 and connected to the circuit layer 10, and the other end is in contact connection with the shielding layer 30.

Specifically, the metal layer 21 is larger than the depth of the groove 13, and the thickness thereof is 100-150 μm. The metal level 21 fills recess 13 with through-hole 41 in the adhesive layer 40, and the metal level 21 is kept away from a surface of circuit layer 10 with adhesive layer 40 keeps away from a surface of circuit layer 10 is located the coplanar, thereby eliminates circuit layer 10 with the segment difference between the adhesive layer 40 prevents that the phenomenon is pasted to the virtual appearance of shielding layer 30, makes shielding layer 30 can be fixed smoothly on the back 12 of circuit layer 10.

In embodiments 1 and 2 of the present invention, the number of the conductive units, the grooves, and the through holes is 2, but the number of the conductive units, the grooves, and the through holes in the flexible circuit board and the display module provided in other embodiments of the present invention is not limited to be 1, and may be 3 or more than 3, but the structure thereof is similar to that of the flexible circuit board and the display module provided in embodiments 1 and 2 of the present invention, and therefore, redundant description thereof is not repeated here. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.

Claims

1. A flexible circuit board, comprising:

the circuit layer is provided with at least one groove on one surface;

the shielding layer is attached to the surface, provided with the groove, of the circuit layer;

the adhesive layer is arranged between the shielding layer and the circuit layer;

and the conductive unit is filled in the groove and penetrates through the adhesive layer to be electrically connected with the shielding layer.

2. The flexible circuit board of claim 1, wherein the adhesive layer is provided with at least one through hole, the through hole corresponds to the groove, and the conductive unit fills the through hole.

3. The flexible circuit board of claim 2, wherein an orthographic projection of the via on the circuit layer coincides with an orthographic projection of the groove on the circuit layer.

4. The flexible circuit board of claim 1, wherein a surface of the conductive element away from the circuit layer is coplanar with a surface of the adhesive layer away from the circuit layer.

5. The flexible circuit board of claim 1, wherein the conductive unit comprises:

and the metal layer is arranged in the groove.

6. The flexible circuit board of claim 5, wherein the conductive unit further comprises:

and the conductive adhesive layer is arranged on the metal layer and one surface of the metal layer, which faces the shielding layer.

7. The flexible circuit board of claim 5, wherein the metal layer has a thickness of less than or equal to 150 microns.

8. The flexible circuit board of claim 5, wherein the metal layer comprises copper.

9. The flexible circuit board of claim 1, wherein a depth of the groove is less than a thickness of the conductive element.

10. A display module comprising the flexible circuit board according to any one of claims 1 to 9.