CN212660364U

CN212660364U - Flexible circuit board, display module and electronic equipment

Info

Publication number: CN212660364U
Application number: CN202021173231.XU
Authority: CN
Inventors: 刘宣宣
Original assignee: OFilm Microelectronics Technology Co Ltd
Current assignee: Jiangxi Oumaisi Microelectronics Co Ltd
Priority date: 2020-06-22
Filing date: 2020-06-22
Publication date: 2021-03-05
Anticipated expiration: 2030-06-22

Abstract

The utility model discloses a flexible circuit board, including base plate and the overburden of range upon range of setting, press from both sides between base plate and the overburden and establish a plurality of butt joint conductors that extend by copper foil circuit in the base plate, butt joint conductor includes butt joint portion, and butt joint portion passes through conducting resin and is connected with external circuit, carries out signal transmission, and the overburden is close to the border of butt joint conductor and is first border, and first border sets up with the butt joint portion interval, forms the buffer, and the conducting resin of avoiding gathers at the free electron of first border department. This application is through setting up the buffer between the first border at the overburden and the butt joint portion of butt joint conductor, for the overflow of conducting resin provides the headspace, has avoided butt joint portion and external connection pin butt joint in-process, and free electron in first border department gathers, causes butt joint conductor's short circuit. The application also provides a display module and an electronic device.

Description

Flexible circuit board, display module and electronic equipment

Technical Field

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

Background

FPC (Flexible Printed Circuit) is a Flexible Printed Circuit board which is made of polyimide or polyester film as a base material and has high reliability and excellent properties. Due to the characteristics of good reliability, strong expansibility and the like, the method is widely applied to the preparation of free electronic devices, particularly display equipment, a covering layer of an FPC (flexible printed circuit) is usually extended into a TFT (Thin Film Transistor), a connecting point filled in the whole FPC is bonded with the connecting point of the TFT through a conductive adhesive Film, and when the conductive adhesive is subjected to hot-pressing bonding, an adhesive overflow phenomenon usually occurs, so that a large number of conductive particles in the conductive adhesive are gathered at the edge of the covering layer of the FPC, and short circuit between adjacent connecting points on the FPC is caused.

SUMMERY OF THE UTILITY MODEL

The application provides a flexible line way board carries out the interval with the first border of its overburden and butt joint portion to the conductor and sets up and form the buffer, has solved butt joint portion and external pin butt joint in-process, because of the excessive short circuit problem that glues and bring of conducting resin.

In a first aspect, the application provides a flexible circuit board, including base plate and the overburden that range upon range of setting, the base plate with press from both sides between the overburden establish a plurality of by the butt joint conductor that copper foil circuit extends in the base plate, the butt joint conductor includes butt joint portion, butt joint portion is connected with outside connecting pin electricity through the conducting resin, carries out signal transmission, the overburden is close to the border of butt joint conductor is first border, first border with butt joint portion interval sets up and forms the buffer, avoids the conducting resin is in free electron of first border department gathers. The butt-joint conductor in the embodiment is an external electric connection point of a circuit on the substrate, the butt-joint part of the butt-joint conductor is electrically connected with an external connection conduit through conductive adhesive, and the external electric connection of the whole flexible circuit board is realized through the butt-joint conductor. If the buffer zone is present, the conductive paste flowing in the direction of the cover layer is blocked by the first edge and accumulates at the first edge. The conductive adhesive, as a bonding material with free electrons, inevitably causes a large amount of free electrons to gather at the first edge, thereby causing short circuit between the plurality of butted conductors.

In a possible embodiment, the first edge is a first direction along a direction toward the docking portion, and a width of the buffer area in the first direction is in a range of 0.3mm to 0.6 mm. The width of the buffer area is the distance between the first edge and the butt joint part, in the embodiment, when the conductive adhesive on the butt joint part is hot-pressed, the conductive adhesive can overflow to the periphery, the buffer area with the thickness of 0.3-0.6 mm can be used for accommodating the conductive adhesive flowing to the direction of the covering layer, and due to the buffer area with the thickness of 0.3-0.6 mm, the conductive adhesive is spread, so that the conductive adhesive can not be converged at the first edge, and the free electron convergence phenomenon can not occur.

In a possible embodiment, the first edge is concave-convex. The first edge of the covering layer of the embodiment is concave-convex, so that when the conductive adhesive is heated and pressed to converge towards the first edge, the contact surface of the conductive adhesive and the first edge is increased due to the concave-convex design, and the gathering phenomenon of free electrons at the first edge can be relieved.

In one possible embodiment, the first edge is a trigonometric function waveform. The trigonometric function waveform is a concave-convex concrete expression form, the trigonometric function waveform mainly refers to a sine waveform, the first edge of the trigonometric function waveform can increase the contact area of the heat-conducting glue and the heat-conducting glue, and the gathering phenomenon of free electrons at the first edge is slowed down.

In one possible embodiment, the first edge is a pulsed square waveform. The pulse square waveform is a concave-convex concrete expression form, the first edge of the pulse square waveform can increase the contact area of the heat-conducting glue and the pulse square waveform, and the gathering phenomenon of free electrons at the first edge is relieved.

In one possible embodiment, the first edge is a sawtooth waveform. The sawtooth waveform is a concave-convex concrete expression form, the first edge of the sawtooth waveform can increase the contact area of the heat-conducting glue and the sawtooth waveform, and the gathering phenomenon of free electrons at the first edge is slowed down

In a possible embodiment, a plurality of the butting conductors are distributed on the substrate in parallel and at equal intervals. The parallel equally spaced butt conductors ensure that the distance between every two adjacent butt conductors is the same, i.e. the area of the spacing region between adjacent butt conductors is the same. Therefore, when the conductive adhesive overflows, the conductive adhesive can be uniformly shunted to the spacing area between the butt-joint conductors, and the phenomenon that the free electrons gather due to the fact that the distance between the two butt-joint conductors is too small, the spacing area is insufficient, and the conductive adhesive flows to the first edge in an excessive mode is avoided.

In a second aspect, the present application provides a display module, which includes a display panel and the flexible circuit board, wherein the connection pins on the display panel are electrically connected to the butt joint portion through conductive adhesives. The connection pin on the display panel is connected with the butt joint part through the conductive adhesive, so that the electric connection between the display panel and the flexible circuit board is realized, and in the process of the electric connection between the display panel and the flexible circuit board, because the first edge of the covering layer on the flexible circuit board and the butt joint part of the butt joint conductor are arranged at intervals to form a buffer area, the problem of free electron concentration caused by the overflow of the conductive adhesive in the butt joint process of the butt joint part and the connection pin is solved.

In a possible embodiment, the conductive adhesive is an anisotropic conductive adhesive, and the butting direction of the butting portion and the connecting pin is a conductive direction of the anisotropic conductive adhesive.

In a third aspect, the present application provides an electronic device including the display module described above.

The application provides a flexible circuit board, through set up the buffer between the first border at the overburden and the butt joint portion of butt joint conductor, for overflowing of conducting resin provides the headspace, avoided butt joint portion and external connection pin butt joint in-process, assemble at first border because of the conducting resin, cause the free electron of first border department to gather, cause the butt joint conductor to take place the short circuit.

Drawings

FIG. 1 is a schematic diagram of a side view structure of a flexible circuit board and a display panel in a prior art;

FIG. 2 is a schematic diagram of a prior art bottom view of a flexible printed circuit board and a display panel;

FIG. 3 is a side view block diagram of a flexible circuit board in one embodiment of the present application;

FIG. 4 is a bottom view of a flexible circuit board according to one embodiment of the present application;

FIG. 5 is a schematic diagram of a side view structure of a flexible printed circuit board and a display panel in an embodiment of the present application;

FIG. 6 is a schematic bottom view of an embodiment of the present application illustrating the docking of a flexible printed circuit board and a display panel;

fig. 7 is a schematic shape diagram of a first edge of a flexible printed circuit board according to three embodiments of the present application.

Detailed Description

The following description of the embodiments of the present application will be made with reference to the accompanying drawings.

Flexible circuit boards are widely used in free electronic devices due to their good flexibility and assembly properties. As shown in fig. 1 and fig. 2, it is a structure diagram of a flexible circuit board and an external display panel 20 in the prior art. The butting conductors 11 on the flexible circuit board and the connection pins 21 on the display panel 20 are bonded together by the thermal conductive adhesive 30 to form an electrical connection. The thermal conductive adhesive 30 overflows around during the thermal pressing process, so that a part of the thermal conductive adhesive 30 is gathered at the first edge 121 of the flexible circuit board cover layer 12, and the conductive adhesive 30, as an electrical adhesive material, contains a large number of free electrons 31 therein, and the free electrons 31 are also gathered at the first edge 121. As shown in fig. 2, a large amount of free electrons 31 are gathered at the junction of the first edge 121 and the butting conductor 11, which causes a short circuit phenomenon between two adjacent butting conductors 11, and further affects the performance of the entire flexible circuit board.

As shown in fig. 3 to 4, in order to solve the above problem, the present application provides a flexible circuit board 50, where the flexible circuit board 50 includes a substrate 10 and a cover layer 12, which are stacked, and the substrate 10 is usually made of polyimide (Kapton), polyethylene terephthalate (PET), aramid fiber paper (Nomex), or polyvinyl chloride (PVC), so as to improve flexibility of the whole flexible circuit board 50, and the substrate 10 plays a role in supporting and shaping a copper foil circuit (not shown in the figure) disposed thereon. The cover layer 12 serves as a protective layer, and mainly serves to protect the copper foil circuit on the substrate 10. A plurality of butting conductors 11 are interposed between the cover layer 12 and the substrate 10, and the butting conductors 11 are led out from the copper foil circuit and are used for connecting with an external circuit, thereby realizing the electrical connection between the copper foil circuit and the external circuit. In general, a copper foil circuit is distributed in the central region where the cover layer 12 and the substrate 10 are bonded, the mating conductor 11 is provided in the edge region of the cover layer 12 and the substrate 10, and a part of the mating conductor 11 is exposed without being covered by the cover layer 12 and is used for connection with an external circuit. The abutting portion 111 is the abutting portion 11 connected to the external circuit, and it is understood that the abutting portion 111 of the abutting portion 11 is not covered by the cover layer 12 and is exposed, so that the abutting portion 111 is easily abutted to the external circuit. In the embodiment of the present application, the covering layer 12 is spaced from the abutting portion 111 near the first edge 121 of the abutting portion 111, i.e. the first edge 121 and the abutting portion 111 are kept at a certain distance D, so that a buffer zone is formed between the spaced first edge 121 and the abutting portion 111. When the butt joint part 111 is bonded with the external circuit through the conductive adhesive, the conductive adhesive overflows to the periphery through hot pressing treatment, and due to the existence of the buffer area, the overflowing conductive adhesive cannot be gathered at the position where the first edge 121 and the butt joint conductor 11 are stacked, so that the gathering of a large amount of free electrons at the position is avoided.

To better illustrate the advantageous effects of the embodiments, as shown in fig. 5 and 6, the electrical connection between the display panel 20 and the flexible circuit board 50 is taken as an example for detailed description. Fig. 5 is a side view structural view of the electrical connection between the display panel 20 and the flexible circuit board 50, in which the flexible circuit board 50 includes a substrate 10 and a cover layer 12 which are stacked, and a copper foil circuit (not shown) on the substrate 10 is electrically connected to the display panel 20 through a butting conductor 11, where the display panel 20 may be a Thin Film Transistor (TFT) panel. The portion of the mating conductor 11 used for electrical connection is a mating portion 111, the mating portion 111 is not covered by the cover layer 12, and a certain distance D is maintained between the mating portion 111 and the first edge 121 of the cover layer 12. As shown in fig. 6, which is a bottom view of the electrical connection between the display panel 20 and the flexible circuit board 50, a distance D is kept between the first edge 121 of the cover layer 12 and the abutting portion 111, so as to form a buffer region 15 (enclosed by a dashed line frame). As shown in fig. 5 and 6, the connection pins 21 on the display panel 20 are electrically connected to the butting portions 111 of the butting conductors 11 through the conductive paste 30. Specifically, the connection pin 21 and the butting portion 111 are electrically connected by thermal compression bonding: firstly, the conductive adhesive 30 is adhered to the butting part 111 by means of pasting or printing coating, then the other side of the conductive adhesive 30 is covered on the connecting pin 21 for alignment, finally, the butting part 111 and the connecting pin 21 are subjected to hot pressing treatment, and the conductive adhesive 30 is melted and cooled to realize the adhesion of the butting part 111 and the connecting pin 21. In the process of hot pressing, as the distance between the abutting portion 111 and the connecting pin 21 is reduced, the conductive adhesive 30 initially attached to the abutting portion 111 overflows outward under the condition of hot pressing, and the overflowing conductive adhesive 20 flows toward the covering layer 12 along the gap between two adjacent abutting conductors 11, since the first edge 121 and the abutting portion 111 are arranged at an interval to form the buffer region 15 in the present embodiment, the buffer region 15 can accommodate a large amount of conductive adhesive 30, thereby avoiding the aggregation of the conductive adhesive 30 at the first edge 121 and the free electrons 31 at the first edge 121 from being aggregated.

In a specific embodiment, as shown in fig. 3 and 5, the direction of the first edge 121 toward the docking portion 111 is the first direction X, and the width of the buffer area 15 in the first direction X ranges from 0.3mm to 0.6mm, i.e., the distance D between the first edge 121 and the docking portion 111 ranges from 0.3mm to 0.6 mm. When the conductive adhesive 30 on the butt-joint part 111 is hot-pressed, the conductive adhesive will overflow to the periphery, the buffer area 15 with 0.3-0.6 mm can be used for accommodating the conductive adhesive 30 flowing to the direction of the covering layer 12, and because of the buffer area with 0.3-0.6 mm, the conductive adhesive 30 is spread, and will not converge on the first edge 121, and the free electron concentration phenomenon will not occur.

In one particular embodiment, as shown in fig. 6 and 7, the first edge 121 is concave-convex. The first edge 121 of the cover layer 12 of the embodiment is concave-convex, so that when the conductive adhesive 30 is thermally pressed to converge toward the first edge 121, the contact surface between the conductive adhesive 30 and the first edge 121 is increased due to the concave-convex design, thereby alleviating the accumulation of the free electrons 31 at the first edge 121. The concave-convex first edge 121 can be a trigonometric function waveform, a pulse square wave waveform and a sawtooth waveform, and the contact area between the first edge 121 of the three waveforms and the heat-conducting glue 30 can be increased, so that the gathering phenomenon of free electrons 31 at the first edge 121 is avoided, and the short circuit of the adjacent butt-joint conductors 11 is avoided.

In a specific embodiment, as shown in fig. 4 and 6, a plurality of butting conductors 11 are distributed on the substrate 10 in parallel at equal intervals. The parallel equally spaced butt conductors 11 ensure that the distance between each two adjacent butt conductors 11 is the same, i.e. the area of the separation region between adjacent butt conductors 11 is the same. Thus, when the conductive adhesive 30 overflows, the spacing area between the butting conductors 11 can be uniformly shunted, and the phenomenon that the free electrons 31 are gathered due to the fact that the distance between the two butting conductors 11 is too small, the spacing area is not enough, and the conductive adhesive 30 flows to the first edge 121 too much is avoided.

As shown in fig. 5 and fig. 6, a second aspect of the present application provides a display module 100, the display module 100 includes a display panel 20 and the flexible circuit board 50, and the connection pins 21 on the display panel 20 are electrically connected to the docking portion 111 through conductive adhesives 30. The connection pins 21 on the display panel 20 are connected with the butting portion 111 through the conductive adhesive 30, so that the display panel 20 and the flexible circuit board 50 are electrically connected, and in the process of electrically connecting the display panel 20 and the flexible circuit board 50, the buffer area 15 is formed by arranging the first edge 121 of the cover layer 12 on the flexible circuit board 50 and the butting portion 111 of the butting conductor 11 at intervals, so that the problem of gathering of free electrons 31 caused by adhesive overflow of the conductive adhesive 30 in the process of butting the butting portion 111 and the connection pins 21 is solved.

Specifically, the conductive paste 30 in the embodiment is an anisotropic conductive paste, and the butting direction of the butting portion 111 and the connecting pin 31 is the conductive direction of the anisotropic conductive paste. The anisotropic conductive adhesive has the characteristic of conducting electricity in a certain direction, in this case, the butting part 11 and the connecting pin 21 are electrically connected, and the butting direction of the butting part and the connecting pin is the conducting direction of the anisotropic conductive adhesive, so that the conducting phenomenon in other directions caused by the overflow of the conductive adhesive 30 is avoided.

Finally, the application also provides electronic equipment which comprises the display module, wherein the electronic equipment can be a mobile phone, a tablet personal computer or other visual electronic equipment.

The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application, and the above description of the embodiments is only provided to help understand the method and the core concept of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. The utility model provides a flexible circuit board, its characterized in that, including base plate and the overburden of range upon range of setting, the base plate with press from both sides between the overburden and establish a plurality of by the butt joint conductor that copper foil circuit extends in the base plate, butt joint conductor includes butt joint portion, butt joint portion passes through conducting resin and external circuit connection, carries out signal transmission, the overburden is close to butt joint conductor's border is first border, first border with butt joint portion interval sets up, first border with form the buffer between the butt joint portion.

2. The flexible circuit board of claim 1, wherein the first edge is a first direction in a direction toward the mating portion, and a width of the buffer area in the first direction is in a range of 0.3mm to 0.6 mm.

3. The flexible circuit board of claim 2, wherein the first edge is concave-convex.

4. The flexible circuit board of claim 3, wherein the first edge is a trigonometric function waveform.

5. The flexible circuit board of claim 3, wherein the first edge is a pulsed square waveform.

6. The flexible circuit board of claim 3, wherein the first edge is a sawtooth waveform.

7. The flexible circuit board of claim 1, wherein a plurality of said mating conductors are equally spaced on said substrate.

8. The flexible circuit board of claim 1, wherein the conductive adhesive is anisotropic conductive adhesive, and the mating direction of the mating portion and the connection pin is a conductive direction of the anisotropic conductive adhesive.

9. A display module comprising a display panel and the flexible circuit board as claimed in any one of claims 1 to 8, wherein the connection pins on the display panel are electrically connected to the docking portion through conductive adhesive.

10. An electronic device comprising the display module of claim 9.