KR20190110371A - Flexible circuit board and manufacturing method thereof - Google Patents

Abstract

A flexible circuit board and a manufacturing method therefor are disclosed in the present invention. The flexible circuit board comprises: a signal line transmitting a high frequency signal; a first ground layer spaced apart from the signal line in a first direction; a second ground layer spaced apart in a second direction of the signal line; and a dielectric layer formed in the first and second directions of the signal line such that the signal line is spaced apart from the first ground layer and the second ground layer. The first ground layer and the second ground layer are conductive through a hot melt conductive adhesive or a gluing agent. According to an embodiment of the present invention, the same tunnel type ground as a coaxial cable can be manufactured, there is no risk of corrosion even during exposure to air by using the conductive gluing agent or the conductive adhesive, costs can be reduced by reducing the number of processes, and thin products can be manufactured.

Description

Flexible circuit board and manufacturing method thereof

The present invention relates to a flexible circuit board and a method of manufacturing the same. More particularly, the present invention relates to a flexible circuit board for transmitting a high frequency signal connecting upper and lower grounds without a via hole, and a method of manufacturing the same.

The contents described below merely provide background information related to the present invention and do not constitute a prior art.

In general, wireless devices such as mobile phones and tablets are provided with a transmission line for transmitting a high frequency signal.

Conventional transmission lines have mainly used coaxial cables, but as the size of wireless devices has become smaller in recent years, the internal space of wireless devices has gradually narrowed, and thus, flexible circuit boards having a smaller space than the coaxial cables have been used.

In addition, the trend of miniaturization of the wireless device, as well as the addition of various functions to the wireless device, the space inside the wireless device is becoming more narrow, and in response to this trend, the development of a miniaturized flexible circuit board is required.

Conventionally, a coaxial cable is used to replace a flexible circuit board, but recently, a high frequency signal is used, and the ground method of the conventional flexible circuit board does not exhibit sufficient performance, a complicated process, and a poor yield.

Wireless terminals such as mobile phones are equipped with RF (Radio Frequency) signal lines, but conventional RF signal lines have been installed in the form of coaxial cables. Flexible circuit boards are commonly used.

Conventional flexible circuit boards have increased the area of the signal line to compensate for the signals lost during signal transmission to secure the required signal amount.

On the other hand, since the impedance decreases as the signal line area increases, impedance matching may be performed by reducing the area of the ground to increase the reduced impedance again.

However, in the related art, when a conductor is contacted or disposed in close proximity to a part of which the area of the ground is reduced, the conductor is electrically connected to the ground, thereby increasing the total area of the ground. Since the signal line corresponding to the ground part is directly exposed to the conductor, there is a problem in that the amount of signal lost during signal transmission increases.

Therefore, the flexible printed circuit board should be mounted at a proper distance from the main board, the sub board, and the battery in order to prevent the impedance change. Therefore, the flexible circuit board has a problem of decreasing the space utilization, which is considered as the greatest advantage. exist.

Of course, the impedance matching may be located close to the main board, the sub-board, and the battery, but even in this case, if the shape or position of the main board, the sub-board, the battery is changed, the flexibility for impedance matching There is a disadvantage that the shape of the circuit board must also be changed.

The technical problem to be achieved by the present invention is to improve the conventional inconvenience, and relates to a flexible circuit board for transmitting a high frequency signal connecting the upper and lower ground without having a via hole and a manufacturing method thereof.

In addition, the technical problem to be achieved by the present invention is to improve the conventional inconvenience, to provide a flexible circuit board and a method of manufacturing the same to make a tunnel-like ground as a coaxial cable.

In addition, the technical problem to be achieved by the present invention is to improve the conventional inconveniences, to provide a flexible circuit board and a method of manufacturing the same, even if exposed to air using a conductive adhesive or conductive adhesive.

In addition, the technical problem to be achieved by the present invention is to improve the conventional inconvenience, to provide a flexible circuit board and a method of manufacturing the flexible circuit board which can reduce the cost, the manufacturing cost can be reduced by reducing the process.

The flexible circuit board according to the characteristics of the present invention for solving this problem,

A signal line for transmitting a high frequency signal;

A first ground layer spaced apart from the signal line in a first direction;

A second ground layer spaced apart in a second direction of the signal line;

A dielectric layer formed in a first direction and a second direction of the signal line so that the signal line is spaced apart from the first ground layer and the second ground layer,

The first ground layer and the second ground layer are characterized in that the conductive to the hot-melt conductive adhesive or adhesive.

The pattern is connected to the first ground layer or the second ground layer on the same line as the signal line or on the opposite side of the dielectric to form a pattern connected to the connector.

The first ground layer and the second ground layer may be conductive by a hot press process.

The manufacturing method of the flexible circuit board which concerns on the characteristic of this invention for solving this subject,

Forming at least one signal line pattern, a first ground pattern, and a second ground pattern from a raw material pattern in which a conductor layer is stacked on the dielectric layer;

Forming a dielectric coverlay between the signal line patterns;

The first ground layer and the second ground layer includes the step of conducting by a hot press process.

According to an embodiment of the present invention, a flexible circuit board for transmitting a high frequency signal connecting upper and lower grounds without a via hole and a manufacturing method thereof may be provided.

Can be.

In addition, in the embodiment of the present invention, it is possible to provide a flexible circuit board and a method of manufacturing the same that makes the same tunnel-type ground as the coaxial cable.

In addition, in the embodiment of the present invention, it is possible to provide a flexible circuit board and a method of manufacturing the same, which are not exposed to air even when exposed to air by using a conductive adhesive or a conductive adhesive.

In addition, in the embodiment of the present invention, it is possible to provide a flexible circuit board and a method for manufacturing the same, which can reduce the cost and reduce the cost, and can manufacture a thin product.

1 is a plan view of a flexible circuit board according to an embodiment of the present invention.
2 is a cross-sectional view of a flexible circuit board according to an embodiment of the present invention.
3 to 6 illustrate a method of manufacturing a flexible circuit board according to an exemplary embodiment of the present invention.
7 to 11 are diagrams illustrating a multi-manufacturing method of a flexible circuit board according to an embodiment of the present invention.
12 is a view showing raw materials in the manufacture of a flexible circuit board according to an embodiment of the present invention.
13 is a view showing the thickness of a substrate according to a conventional method for manufacturing a flexible circuit board.
14 is a diagram illustrating a thickness of a substrate according to a method of manufacturing a flexible circuit board according to an exemplary embodiment of the present invention.
15 is a view showing the unit price according to the conventional method for manufacturing a flexible circuit board.
16 is a view comparing unit costs of a method of manufacturing a flexible circuit board according to an exemplary embodiment of the present invention and a conventional manufacturing method.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

1 is a plan view of a flexible circuit board according to an embodiment of the present invention.

2 is a cross-sectional view of a flexible circuit board according to an embodiment of the present invention.

1 or 2, a flexible circuit board according to an embodiment of the present invention,

A signal line 100 for transmitting a high frequency signal;

A first ground layer 210 spaced apart from the signal line 100 in a first direction;

A second ground layer 220 spaced apart in a second direction of the signal line 100;

Dielectric layers 310 and 320 formed in the first and second directions of the signal line 100 such that the signal line 100 is spaced apart from the first ground layer 210 and the second ground layer 220. Including;

The first ground layer 210 and the second ground layer 220 may be electrically conductive with a hot melt conductive adhesive or an adhesive 400.

The first ground layer 210 and the second ground layer 220 may be used by the Japanese Tatsuda PC 5000 series, PC 6000 series, FC series.

The dielectric layers disposed in the first direction (upper) and the second direction (lower) to separate the signal line 100 from the first ground layer 210 and the second ground layer 220 are PET, polyimide, and nanostructures. Can be one of Teflon.

The pattern is connected to the first ground layer 210 or the second ground layer on the same line as the signal line 100 or on the opposite surface of the dielectric to form a pattern connected to the connector.

The first ground layer 210 and the second ground layer 220 are conductive by a hot press process. That is, in the embodiment of the present invention, the first ground and the second ground are electrically connected without using the via hole.

The first ground layer 210 or the second ground layer 220 may be SMT solder bonded to the PCB.

In order to prevent the conductive adhesive or the conductive adhesive 400 from being exposed to the outside, insulating layers 510 and 520 covering the conductive adhesive or the conductive adhesive 400 may be formed. In other words, in order to prevent the conductive adhesive from being exposed to the side surface, the insulating layers 510 and 520 may be formed once more using a similar coverlay.

Since the signal line line and the ground line refer to the same as the signal line pattern and the ground pattern in the above or the following process, the same reference numerals are used.

Method of manufacturing a flexible circuit board according to an embodiment of the present invention having such a configuration is as follows.

3 to 6 illustrate a method of manufacturing a flexible circuit board according to an exemplary embodiment of the present invention.

First, the signal line pattern 100, the first ground pattern 210, and the second ground pattern 220 are formed on the raw material pattern in which the conductor layer 101 is stacked on the dielectric layer 310 as shown in FIG. 3. . Here, the raw material pattern may be PI, and form a pattern in the cross section.

The ground patterns of the first ground pattern 210 and the second ground pattern 220 on the left and right sides may be made the same as the signal line pattern 100, or only the connector connection portion may be made. That is, the first ground pattern 210 and the second ground pattern 220 may be connected to connect only the connector.

Then, as shown in FIG. 5, a dielectric coverlay 320 is formed around the signal line pattern 100.

Then, as illustrated in FIG. 6, the conductive adhesive or the adhesive 400 is adhered to the first ground layer 210 and the second ground layer 220 by a hot press process, to thereby form the first ground layer 210 and the second ground. Layer 220 is electrically conductive.

Thereafter, the insulating layers 510 and 520 are additionally formed to complete the flexible circuit board having the shape as shown in FIG. 1.

Such flexible circuit boards can be manufactured in large quantities for efficient manufacturing, and the multi-manufacturing method will be described as follows.

7 to 11 are views illustrating a multi-manufacturing method of a flexible circuit board according to an embodiment of the present invention.

First, the signal line pattern 100, the first ground pattern 210, and the second ground pattern 220 are formed on the raw material pattern in which the conductor layer 101 is stacked on the dielectric layer 310 as shown in FIG. 7. . The raw material here may be PI, and form a pattern in the cross section. The signal line pattern 100 may be one or more. And the ground pattern can be inserted or omitted.

The ground patterns of the first ground pattern 210 and the second ground pattern 220 on the left and right sides may be made the same as the signal line pattern 100, or only the connector connection portion may be made. That is, the first ground pattern 210 and the second ground pattern 220 may be connected to connect only the connector.

After etching, a partial cutting operation may be performed, and there may or may not be a ground pattern between the signal line patterns 100.

If the distance between the signal line lines 100 is narrow, it may be comfortable that there is no ground.

Then, as shown in FIG. 9, a dielectric coverlay is formed around the signal line pattern 100.

Then, as illustrated in FIG. 10, the conductive adhesive or the adhesive is adhered to the first ground layer 210 and the second ground layer 220 by a hot press process, so that the first ground layer 210 and the second ground layer 220 are formed. Electrical conduction). If necessary, the upper surface of the signal line may be cut and attached.

Thereafter, as shown in FIG. 10, the insulating layers 510 and 520 are additionally generated, and a plurality of flexible circuit boards are completed by cutting to suit the product as shown in FIG. 11.

In fact, comparing the manufacturing method of the embodiment of the present invention and the existing manufacturing method of making such a flexible circuit board as follows.

12 is a view showing a raw material when manufacturing a flexible circuit board according to an embodiment of the present invention, Figure 13 is a view showing the thickness of the substrate according to a conventional method for manufacturing a flexible circuit board, Figure 14 is an embodiment of the present invention FIG. 15 is a view illustrating a thickness of a substrate according to a method of manufacturing a flexible circuit board according to an example, and FIG. 15 is a view comparing unit costs of a manufacturing method of a flexible circuit board and a conventional manufacturing method according to an embodiment of the present invention.

Referring to FIG. 13 at the time of manufacturing a flexible circuit board using the raw material as shown in FIG. 12, the thickness of the substrate is about 213.5 um. However, in the present invention as shown in FIG. 14, the thickness is 112.5 um.

In addition, referring to FIG. 15, although the manufacturing cost is about 118,000 won in the related art, in the present invention as shown in FIG.

In the above embodiment of the present invention, the same tunnel type ground as that of the coaxial cable can be made.

Moreover, in the Example of this invention, even if it exposes to air using a conductive adhesive or a conductive adhesive, there is no danger of corrosion.

In addition, in the embodiment of the present invention, the process is reduced to reduce the cost, it is possible to manufacture a thin product.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (6)

A signal line for transmitting a high frequency signal;
A first ground layer spaced apart from the signal line in a first direction;
A second ground layer spaced apart in a second direction of the signal line;
A dielectric layer formed in a first direction and a second direction of the signal line so that the signal line is spaced apart from the first ground layer and the second ground layer,
And the first ground layer and the second ground layer are conductive with a hot melt conductive adhesive or an adhesive. The method of claim 1,
And a pattern connected to the first ground layer or the second ground layer on the same line as the signal line or on the opposite side of the dielectric to form a connector. The method of claim 1,
And the first ground layer and the second ground layer are conducted by a hot press process. The method of claim 3,
In order to prevent the said conductive adhesive or conductive adhesive from being exposed to the outside, the flexible circuit board characterized by forming the insulating layer which covers the said conductive adhesive or conductive adhesive. Forming at least one signal line pattern, a first ground pattern, and a second ground pattern from a raw material pattern in which a conductor layer is stacked on the dielectric layer;
Forming a dielectric coverlay between the signal line patterns;
And conducting the first ground layer and the second ground layer by a hot press process. The method of claim 5,
And forming an insulation layer covering the conductive adhesive or the conductive adhesive to prevent the conductive adhesive or the conductive adhesive from being exposed to the outside.

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