CN217509127U

CN217509127U - Flexible circuit board suitable for ultrasonic welding

Info

Publication number: CN217509127U
Application number: CN202220689199.3U
Authority: CN
Inventors: 孙士卫; 黄庆林
Original assignee: Dalian Jixing Electronics Inc ltd
Current assignee: Dalian Jixing Electronics Inc ltd
Priority date: 2022-03-28
Filing date: 2022-03-28
Publication date: 2022-09-27
Anticipated expiration: 2032-03-28

Abstract

The utility model discloses a flexible line way board suitable for ultrasonic bonding, including circuit area top polyimide layer, copper foil layer and circuit area bottom polyimide layer, circuit area top polyimide layer lays above the copper foil layer through circuit area top glue film, circuit area bottom polyimide layer lays below the copper foil layer through circuit area bottom glue film, be formed with the conducting wire on the copper foil layer; the circuit area top polyimide layer, the circuit area top adhesive layer, the circuit area bottom polyimide layer and the circuit area bottom adhesive layer are provided with notches at welding ends to expose the copper foil layer, and the copper foil layer exposed between every two adjacent flexible circuit board bodies is welded in an ultrasonic mode. The flexible circuit board body seamless welding can be realized to this application, can guarantee that circuit resistivity is extremely low nearly zero, and the butt fusion process does not have the spark, environmental protection safety.

Description

Flexible circuit board suitable for ultrasonic welding

Technical Field

The utility model relates to a flexible line way board equipment technical field, concretely relates to flexible line way board suitable for ultrasonic bonding.

Background

In recent years, electronic accessories have come into widespread use in various fields and are being updated at a development rate of several generations per year. Printed circuit boards, which are important components of electronic accessories, are also constantly being improved and updated. The FPC is a main development trend of the printed circuit board due to its characteristics of convenience, smallness, high density, and high performance. Along with the improvement of living standard of people, the material aspect also has certain requirement to the aspect thereupon, especially in the aspect of electronic auxiliary material, not only explains practicality pleasing to the eye, also the requirement in the aspects such as volume, integrated level, function of auxiliary material is more and more high. With the development of the industry, the application field of the FPC is continuously increased, the demand is continuously increased, the requirements on the FPC are also diversified, more use spaces are expanded in order to better meet the market demand, and meanwhile, the production cost is reduced, so that the product structure needs to be continuously optimized.

Aiming at large-size FPC products, the processing can not be finished at one time, a plurality of FPCs are required to be assembled together, and a welding technology is used at the joint.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a flexible line way board suitable for ultrasonic bonding can reduce overall distribution weight, and the space occupancy is low, and seamless butt fusion between the flexible line way board can guarantee that the circuit resistivity is extremely low nearly zero.

In order to achieve the above purpose, the present application provides a flexible printed circuit suitable for ultrasonic welding, including a circuit area top polyimide layer, a copper foil layer, and a circuit area bottom polyimide layer, where the circuit area top polyimide layer is laid on the copper foil layer through a circuit area top adhesive layer, the circuit area bottom polyimide layer is laid below the copper foil layer through a circuit area bottom adhesive layer, and a conductive circuit is formed on the copper foil layer; the circuit area top polyimide layer, the circuit area top adhesive layer, the circuit area bottom polyimide layer and the circuit area bottom adhesive layer are provided with notches at welding ends to expose the copper foil layer, and the copper foil layer exposed between every two adjacent flexible circuit board bodies is welded in an ultrasonic mode.

Further, after copper foil layers exposed between two adjacent flexible circuit board bodies are overlapped and aligned, ultrasonic welding equipment is adopted for welding operation.

Furthermore, the polyimide layer on the top of the welding area is laid on the copper foil layer after welding through the glue layer on the top of the welding area, and the polyimide layer on the bottom of the welding area is laid below the copper foil layer after welding through the glue layer on the bottom of the welding area.

Furthermore, the thickness of the glue layer at the top of the welding area is larger than the sum of the thicknesses of the polyimide layer at the top of the circuit area and the glue layers at the top of the circuit area at two sides, and the thickness of the glue layer at the bottom of the welding area is larger than the sum of the thicknesses of the polyimide layer at the bottom of the circuit area and the glue layers at the bottom of the circuit area at two sides.

Furthermore, when the polyimide layer and the copper foil layer at the top of the circuit area are pressed together, the glue layer at the top of the circuit area flows to fill the gaps between the circuits, and when the polyimide layer and the copper foil layer are pressed together, the glue layer at the bottom of the circuit area flows to fill the gaps between the circuits.

Furthermore, the ratio of the thickness of the top glue layer of the circuit area to the thickness of the circuit area is 1: 1.4, the ratio of the thickness of the bottom glue layer of the circuit area to the thickness of the circuit area is 1: 1.4 or more.

Furthermore, the thickness of the polyimide layer at the top of the line area and the thickness of the polyimide layer at the bottom of the line area are between 7 and 200 micrometers.

Furthermore, the line area top adhesive layer, the line area bottom adhesive layer, the welding area top adhesive layer and the welding area bottom adhesive layer are made of acrylic acid or epoxy resin.

The utility model discloses an above technical scheme, compare with prior art, the advantage that has is: the method can realize seamless welding of the flexible circuit board body, can ensure that the electrical resistivity of the circuit is extremely low and is almost zero, and has no spark in the welding process, environmental protection and safety; the outer layer of the welding zone is provided with the polyimide layer for insulation, the tensile strength is high, the welding line part can be effectively protected, and the welding zone has the characteristics of moisture resistance, water resistance, corrosion resistance and the like. The size of the FPC far exceeds the conventional size under the condition of keeping the performance of the product unchanged through a welding mode, various three-dimensional space wiring requirements can be matched as required, the overall wiring weight is light, and the space occupancy rate is low.

Drawings

FIG. 1 is a schematic diagram of a flexible circuit board suitable for ultrasonic welding;

FIG. 2 is a cross-sectional view of two adjacent flexible printed circuit boards before welding;

fig. 3 is a cross-sectional view of two adjacent flexible circuit board bodies after welding.

Wherein: 1. circuit district top polyimide layer, 2, circuit district top glue film, 3, copper foil layer, 4, circuit district bottom glue film, 5, circuit district bottom polyimide layer, 6, the copper foil layer that exposes, 7, welding district top polyimide layer, 8, welding district top glue film, 9, welding district bottom glue film, 10, welding district bottom polyimide layer, 11, the copper foil layer after the butt fusion.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the application, i.e., the embodiments described are only a subset of, and not all embodiments of the application. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present application without making any creative effort, shall fall within the protection scope of the present application.

Example 1

As shown in fig. 1 to 3, the present embodiment provides a flexible wiring board suitable for ultrasonic welding, including:

the thickness of the polyimide layer 1 on the top of the circuit area is 7-200 microns, and can be selected according to performance requirements such as different structures, tensile strength and the like.

The top glue layer 2 of the circuit area comprises acrylic acid or epoxy resin, and the ratio of the thickness to the thickness of the circuit is 1: 1.4 or more matching selection. The polyimide layer 1 and the copper foil layer 3 on the top of the circuit area are pressed together at high temperature and high pressure, and meanwhile, the glue layer 2 on the top of the circuit area flows to fill gaps between circuits in the pressing process. The pressing parameters can be 180 ℃, 110Kgf of pressure and 180S of time.

The copper foil layer 3, it forms the necessary conducting circuit through FPC's dry film of pressing-exposing-developing-etching-demolding mode;

the bottom glue layer 4 of the circuit area comprises acrylic acid or epoxy resin, and the ratio of the thickness to the thickness of the circuit is 1: 1.4 or more matching choices. The polyimide layer 5 at the bottom of the circuit area and the copper foil layer 3 are pressed together at high temperature and high pressure, and meanwhile, the glue layer 4 at the bottom of the circuit area flows to fill gaps between circuits in the pressing process. The pressing parameters can be 180 ℃, 110Kgf of pressure and 180S of time.

The thickness of the polyimide layer 5 at the bottom of the circuit area is 7-200 microns, and can be selected according to performance requirements such as different structures, tensile strength and the like.

The exposed copper foil layer 6 has only one layer of copper foil on the circuit part before welding, and the copper foil is directly contacted with the copper foil for welding operation during welding. The ultrasonic welding parameters may be: power 1400KW, pressure 0.5MPa, time 1S.

And a polyimide layer 7 at the top of the welding area is laid on the welded copper foil layer through a welding area top adhesive layer 8.

And the welding zone top glue layer 8 is made of acrylic acid or epoxy resin, and the thickness of the welding zone top glue layer is larger than the sum of the thicknesses of the circuit zone top polyimide layer and the circuit zone top glue layer on the two sides. And pressing the polyimide layer 7 on the top of the welding area and the welded copper foil layer 11 together through high temperature and high pressure. The pressing parameters can be 180 ℃, 110Kgf of pressure and 180S of time.

The bottom glue layer 9 of the welding zone is made of acrylic acid or epoxy resin, and the thickness of the bottom glue layer is larger than the sum of the thicknesses of the polyimide layer at the bottom of the circuit zone and the glue layers at the bottom of the circuit zone on the two sides. And pressing the polyimide layer 10 at the bottom of the welding area and the welded copper foil layer 11 together through high temperature and high pressure. The pressing parameters can be 180 ℃, 110Kgf of pressure and 180S of time.

And a polyimide layer 10 at the bottom of the welding zone is laid below the welded copper foil layer through a welding zone bottom adhesive layer 9.

The manufacturing method of the flexible circuit board comprises the following steps: firstly, pre-bonding a polyimide film 1 at the top of a circuit area and an adhesive layer 2 at the top of the circuit area together, wherein the bonding parameters can be temperature of 110 ℃ and pressure of 0.4 Mpa; and punching the line area top polyimide film 1 and the line area top adhesive layer 2 which are pre-attached together at a welding position to form an opening in the welding area. Then pressing a polyimide film 1 at the top of the circuit area and a glue layer 2 at the top of the circuit area on a copper foil layer, wherein the copper foil layer forms a required conducting circuit by pressing a dry film, exposing, developing, etching and removing the film; pre-bonding the polyimide layer 5 at the bottom of the circuit area and the glue layer 4 at the bottom of the circuit area together, wherein the bonding parameters can be 110 ℃ and 0.4 Mpa; punching the line area bottom polyimide layer 5 and the line area bottom adhesive layer 4 which are pre-attached together at a welding position to form an opening in the welding area, and pressing the line area bottom polyimide layer 5 and the line area bottom adhesive layer 4 under the copper foil layer; after copper foil layers in welding areas between two adjacent flexible circuit board bodies are overlapped and aligned, welding operation is carried out by using ultrasonic welding equipment; pass through the laminating of welding zone top glue film with welding zone top polyimide layer after the butt fusion operation on the copper foil layer after the butt fusion, welding zone bottom polyimide layer passes through welding zone bottom glue film laminating below the copper foil layer after the butt fusion, and welding zone top glue film and welding zone bottom glue film cover the butt fusion part completely and extend to respectively during the laminating more than the circuit district top polyimide layer of both sides, below the circuit district bottom polyimide layer, then carry out the pressfitting operation, accomplish and connect between the flexible line way board body.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.

Claims

1. A flexible circuit board suitable for ultrasonic welding is characterized by comprising a circuit area top polyimide layer, a copper foil layer and a circuit area bottom polyimide layer, wherein the circuit area top polyimide layer is laid on the copper foil layer through a circuit area top glue layer, the circuit area bottom polyimide layer is laid below the copper foil layer through a circuit area bottom glue layer, and a conducting circuit is formed on the copper foil layer; the circuit area top polyimide layer, the circuit area top adhesive layer, the circuit area bottom polyimide layer and the circuit area bottom adhesive layer are provided with notches at welding ends to expose the copper foil layer, and the copper foil layer exposed between every two adjacent flexible circuit board bodies is welded in an ultrasonic mode.

2. The flexible printed circuit board suitable for ultrasonic welding according to claim 1, wherein after the copper foil layers exposed between two adjacent flexible printed circuit boards are overlapped and aligned, an ultrasonic welding device is used for welding.

3. The flexible printed circuit board of claim 1, wherein the polyimide layer at the top of the soldering zone is disposed on the copper foil layer after soldering through a glue layer at the top of the soldering zone, and the polyimide layer at the bottom of the soldering zone is disposed under the copper foil layer after soldering through a glue layer at the bottom of the soldering zone.

4. The flexible printed circuit board of claim 3, wherein the thickness of the top glue layer of the soldering zone is greater than the sum of the thicknesses of the top polyimide layer of the circuit zone and the top glue layer of the circuit zone on both sides, and the thickness of the bottom glue layer of the soldering zone is greater than the sum of the thicknesses of the bottom polyimide layer of the circuit zone and the bottom glue layer of the circuit zone on both sides.

5. The flexible printed circuit board suitable for ultrasonic bonding as claimed in claim 1, wherein when the polyimide layer on the top of the circuit region is bonded to the copper foil layer, the adhesive layer on the top of the circuit region flows to fill the inter-circuit gap, and when the polyimide layer on the bottom of the circuit region is bonded to the copper foil layer, the adhesive layer on the bottom of the circuit region flows to fill the inter-circuit gap.

6. The flexible circuit board suitable for ultrasonic bonding according to claim 1, wherein the ratio of the thickness of the top glue layer to the thickness of the circuit in the circuit area is 1: 1.4, the ratio of the thickness of the bottom glue layer of the circuit area to the thickness of the circuit area is 1: 1.4 or more.

7. The flexible wiring board of claim 1, wherein the thickness of the polyimide layer on the top of the wiring region and the thickness of the polyimide layer on the bottom of the wiring region are between 7 microns and 200 microns.

8. The flexible printed circuit board suitable for ultrasonic bonding according to claim 1, wherein the circuit area top adhesive layer, the circuit area bottom adhesive layer, the welding area top adhesive layer and the welding area bottom adhesive layer are made of acrylic resin or epoxy resin.