Conductive structure for flexible film circuit

Abstract

The utility model provides a positive and negative surface conductive structure applied to flexible film circuit, include: flexible base material layer, flexible base material layer is PET material quality, circuit layer, set up in the positive and negative two sides of flexible base material layer, conductive connection structure is used for realizing the electric connection of flexible base material layer positive and negative two sides circuit layer, and conductive connection structure includes the through -hole of setting up on flexible base material layer and fills in the through -hole and fills in the through -hole around circuit layer on the hole filling conductive layer. This scheme through setting up the through -hole of specific diameter and quantity on flexible base material layer, and adopt the design of multilayer hole filling conductive layer, realized the double -sided printing of circuit, effectively solved the problem that circuit layout single side cannot layout in prior art, reduced the size area of product, this conductive structure adopts the preparation of printing process, and the process is simple, and the cost is low, is fit for large -scale production.

Description

Technical Field

[0001] This utility model relates to the field of flexible electronic device technology, specifically a front and back conductive structure applied in flexible thin film circuits, mainly suitable for printed membrane switches, and especially suitable for membrane switch devices with high requirements for product size and conductivity. Background Technology

[0002] With the trend towards miniaturization and integration in modern electronic devices, membrane switches, as a common input device, face numerous challenges in circuit design. Currently, membrane switch circuit designs are becoming increasingly smaller in size, while the functions and requirements they require are constantly increasing, making it difficult to complete the circuit layout on a single side. Furthermore, the double-sided printing process for printed circuits also presents the problem of poor conductivity in the printed circuitry.

[0003] In existing technologies, when it is necessary to achieve double-sided conduction of the circuit, the following difficulties are often encountered: on the one hand, the space for single-sided layout is insufficient, which cannot meet the circuit layout requirements of complex functions; on the other hand, during the printing process on both sides, the connection reliability of the conductive circuit is poor, and problems such as poor contact and excessive resistance are prone to occur, which seriously affect the performance and reliability of the membrane switch.

[0004] To address these issues, some solutions have been proposed in existing technologies, such as increasing the number of circuit layers and employing complex welding processes. However, these methods often suffer from drawbacks such as complex processes, high costs, and low reliability, failing to meet the requirements of modern membrane switches for high performance and low cost.

[0005] Therefore, in view of the shortcomings of the existing technology, it is necessary to design a front and back conductive structure for use in flexible thin film circuits to solve the above problems. Utility Model Content

[0006] The purpose of this invention is to provide a front and back conductive structure for use in flexible thin film circuits, so as to solve the problems of difficult layout and poor conductivity of thin film switch circuits in the prior art, realize double-sided printing of circuits, reduce product size and area, and reduce the occurrence of poor filling.

[0007] To achieve the above and other related objectives, the technical solution provided by this utility model is: a front and back conductive structure applied in flexible thin-film circuits, comprising:

[0008] A flexible substrate layer, wherein the flexible substrate layer is made of PET material;

[0009] The circuit layer is disposed on both sides of the flexible substrate layer;

[0010] A conductive connection structure is used to realize the electrical connection between the circuit layers on both sides of the flexible substrate layer. The conductive connection structure includes through holes formed on the flexible substrate layer and a via conductive layer filling the through holes and the circuit layers around the through holes.

[0011] The preferred technical solution is that the diameter of the through hole is 0.2mm, the number of holes is 3, and they are evenly distributed at the PAD points where double-sided conduction is required.

[0012] A preferred technical solution is that the via conductive layer includes a first conductive silver paste layer disposed on the back circuit layer of the flexible substrate layer, and a second conductive silver paste layer and a third conductive silver paste layer disposed on the front circuit layer of the flexible substrate layer.

[0013] The preferred technical solution is as follows: the thickness of the first conductive silver paste layer is 8-10 μm, the thickness of the second conductive silver paste layer is 8-10 μm, and the thickness of the third conductive silver paste layer is 8-10 μm.

[0014] The preferred technical solution is that the circuit layer is formed by printing conductive silver paste, the particle size of the conductive silver paste is 1-2μm, and the printing thickness is 5-8μm.

[0015] A preferred technical solution is that it further includes an insulating ink layer disposed on the circuit layer and the via conductive layer, wherein the thickness of the insulating ink layer is 10-15 μm.

[0016] The preferred technical solution is that the through hole is processed using laser drilling technology.

[0017] Due to the application of the above technical solution, the beneficial effects of this utility model are as follows:

[0018] The proposed conductive structure for flexible thin-film circuits achieves double-sided printing by creating vias of a specific diameter and number on the flexible substrate layer and employing a multi-layer conductive layer design. This effectively solves the problem of single-sided circuit layout in existing technologies, reducing the product's size and area. The process of printing one layer of conductive silver paste on the back and two layers of conductive silver paste on the front increases the thickness of the conductive layer, allowing ink to pass through the walls of the PET vias, significantly reducing the occurrence of filling defects and improving the reliability and stability of the conductive structure. This conductive structure is fabricated using a printing process, which is simple, low-cost, and suitable for large-scale production. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the cross-section of the thin-film circuit involved in this utility model. Detailed Implementation

[0020] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.

[0021] Please see Figure 1 It should be noted that in the description of this utility model, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. These terms are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. The terms "horizontal," "vertical," and "suspended," etc., do not indicate that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0022] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] Example:

[0024] like Figure 1 As shown, according to a general technical concept of this utility model, a front and back conductive structure for use in flexible thin-film circuits is provided, comprising:

[0025] Flexible substrate layer 1, which is made of PET material;

[0026] The circuit layer (printed circuit) is disposed on both sides of the flexible substrate layer 1;

[0027] A conductive connection structure is used to realize the electrical connection between the circuit layers on both sides of the flexible substrate layer 1. The conductive connection structure includes a through hole 11 formed on the flexible substrate layer and a via conductive layer filled in the through hole and the circuit layer around the through hole.

[0028] like Figure 1As shown, in an exemplary embodiment of this utility model, the diameter of the through hole 11 is 0.2 mm, and there are 3 of them, which are evenly distributed at the PAD points where double-sided conduction is required.

[0029] like Figure 1 As shown, in an exemplary embodiment of the present invention, the via conductive layer includes a first conductive silver paste layer 21 disposed on the back circuit layer of the flexible substrate layer 1, and a second conductive silver paste layer 22 and a third conductive silver paste layer 23 disposed on the front circuit layer of the flexible substrate layer 1.

[0030] like Figure 1 As shown, in an exemplary embodiment of this utility model, the thickness of the first conductive silver paste layer 21 is 8-10 μm, the thickness of the second conductive silver paste layer 22 is 8-10 μm, and the thickness of the third conductive silver paste layer 23 is 8-10 μm.

[0031] like Figure 1 As shown, in an exemplary embodiment of this utility model, the circuit layer is formed by printing conductive silver paste, the particle size of the conductive silver paste is 1-2μm, and the printing thickness is 5-8μm.

[0032] like Figure 1 As shown, in an exemplary embodiment of this utility model, an insulating ink layer 3 is further provided on the circuit layer and the via conductive layer, the thickness of the insulating ink layer 3 being 10-15 μm.

[0033] like Figure 1 As shown, in one exemplary embodiment of this utility model, the through hole is processed using laser drilling technology.

[0034] In existing technologies, when faced with difficulties in single-sided layout of membrane switch circuits and poor conductivity on both sides, solutions typically involve increasing the number of circuit layers or employing complex soldering processes. These methods suffer from drawbacks such as complex processes, high costs, and low reliability. This invention cleverly solves these problems by optimizing the size and number of through-holes and employing an innovative multi-layer via conductive layer design.

[0035] Specifically, the through-holes in this invention are designed with a diameter of 0.2mm and a quantity of 3. This specific size and number ensures sufficient conductive pathways while avoiding the impact of excessively large through-holes on the mechanical properties of the flexible substrate layer, achieving a balance between structural strength and conductivity. Simultaneously, the one-layer back and two-layer front perforated conductive layer structure increases the thickness of the conductive layer, allowing ink to pass through the PET perforations, effectively improving the reliability of the conductive connection and reducing the occurrence of perforation defects.

[0036] This structural design not only solves the technical problems in existing technologies, but also has a simple process, low cost, and is suitable for large-scale production. It has significant technological progress and practical application value, and is innovative.

[0037] Therefore, this utility model has the following advantages:

[0038] The proposed conductive structure for flexible thin-film circuits achieves double-sided printing by creating vias of a specific diameter and number on the flexible substrate layer and employing a multi-layer conductive layer design. This effectively solves the problem of single-sided circuit layout in existing technologies, reducing the product's size and area. The process of printing one layer of conductive silver paste on the back and two layers of conductive silver paste on the front increases the thickness of the conductive layer, allowing ink to pass through the walls of the PET vias, significantly reducing the occurrence of filling defects and improving the reliability and stability of the conductive structure. This conductive structure is fabricated using a printing process, which is simple, low-cost, and suitable for large-scale production.

[0039] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A positive and negative conductive structure applied in a flexible thin film circuit, characterized in that, include: A flexible substrate layer, wherein the flexible substrate layer is made of PET material; The circuit layer is disposed on both sides of the flexible substrate layer; A conductive connection structure is used to realize the electrical connection between the circuit layers on both sides of the flexible substrate layer. The conductive connection structure includes through holes formed on the flexible substrate layer and a via conductive layer filling the through holes and the circuit layers around the through holes.

2. The positive and negative conductive structure applied in flexible thin-film circuits according to claim 1, characterized in that: The through holes have a diameter of 0.2 mm, and there are 3 of them, which are evenly distributed at the PAD points where double-sided conductivity is required.

3. The positive and negative conductive structure applied in flexible thin-film circuits according to claim 1, characterized in that: The via conductive layer includes a first conductive silver paste layer disposed on the back circuit layer of the flexible substrate layer, and a second and a third conductive silver paste layer disposed on the front circuit layer of the flexible substrate layer.

4. The positive and negative conductive structure applied in flexible thin-film circuits according to claim 3, characterized in that: The thickness of the first conductive silver paste layer is 8-10 μm, the thickness of the second conductive silver paste layer is 8-10 μm, and the thickness of the third conductive silver paste layer is 8-10 μm.

5. The positive and negative conductive structure applied in flexible thin-film circuits according to claim 1, characterized in that: The circuit layer is formed by printing conductive silver paste, the particle size of which is 1-2 μm and the printing thickness is 5-8 μm.

6. The positive and negative conductive structure applied in flexible thin-film circuits according to claim 1, characterized in that: It also includes an insulating ink layer disposed on the circuit layer and the via conductive layer, the thickness of the insulating ink layer being 10-15 μm.

7. The positive and negative conductive structure applied in flexible thin-film circuits according to claim 1, characterized in that: The through hole was formed using laser drilling technology.

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