KR20060002663A - Flexible printed cable - Google Patents

Abstract

According to the present invention, the base film, the first and second copper patterns formed on the first surface and the second surface of the base film, and the first surface of the base film 51 to cover the copper pattern And a flexible printed cable having a first and a second cover film bonded to each other via an adhesive layer on a second surface, wherein the thickness of the base film and the thickness of the first and second cover films are 12.5 microns, respectively. A flexible printed cable is provided, wherein the first and second copper patterns have a thickness of 18 micrometers.

Description

Flexible Printed Cable {Flexible Printed Cable}

1 is an explanatory diagram schematically showing a device equipped with a conventional flexible printed cable.

Shown in FIG. 2 is a schematic plan view of the flexible printed cable 14 shown in FIG. 1.

3 is a schematic cross-sectional view of a flexible printed cable formed of a dual structure.

Shown in FIG. 4 is a cross-sectional view of another example flexible printed cable according to the prior art, which relates to what is called a two metal flexible printed cable.

5 is a schematic cross-sectional view of an embodiment of a printed flexible cable according to the present invention.

Shown in Figure 6 is a schematic cross-sectional view of another part of a flexible printed cable according to the present invention.

<Brief Description of Major Codes in Drawings>

11. Main Unit 12. Rotation Guide

13. Camera 14. Flexible Printed Cable

The present invention relates to a flexible printed cable and a camera phone having the same, and more particularly to a flexible printed cable in which a flexible printed cable connected to a rotating mechanism can be prevented from being damaged by repeated rotating action of the rotating mechanism. It relates to a tide cable and a camera phone having the same.

In general, a flexible printed cable is a cable made to transmit and receive a signal with a power source by interconnecting circuits and circuits or electronic components. Since the flexible printed cable has its own flexibility, it is easy to cope with the situation where the arrangement of parts and circuits requires the flexibility of the cable, and furthermore, the parts or circuits to which the cable is connected can perform linear or rotary motion. Even if they do, they may bend or bend correspondingly. Flexible printed cables are used in all electronic devices, for example, widely used in mobile phones, notebook computers, display devices, and the like.

1 is an explanatory diagram schematically showing a device equipped with a conventional flexible printed cable.

The device shown in the drawing is, for example, a camera phone, the top of the main body 11 of the camera phone is provided with a rotation guide 12, the camera 13 is subjected to the guide action of the rotation guide 12 It is rotatably installed. One end of the flexible printed cable 14 is connected to one side of the main body 11, while the other end is connected to the camera 13. Since the camera 13 performs a rotational motion as indicated by reference numeral A on the upper part of the main body 11 which is fixed, a flexible printed cable which interconnects the camera 13 and the circuit boards provided in the main body 11. 14 receives a bending action according to the movement of the camera 13.

Shown in FIG. 2 is a schematic plan view of the flexible printed cable 14 shown in FIG. 1.

The flexible printed cable 14 shown in the figure has a thin film as a whole, and a copper pattern is formed on the base film, and includes a cover film covering the base film to protect the copper pattern. The flexible printed cable 14 shown in the drawing has a first connector 21, a second connector 22, and an extension 23 interconnecting the connectors.

The flexible printed cable as illustrated in FIGS. 1 and 2 repeats the bending or unfolding of the cable according to the rotational or translational movement of the portion to which it is connected. Stress concentration is applied to the copper pattern formed in the. Due to such stress concentrations, cracks may occur in the copper pattern of the flexible printed cable. Cracks on the cable copper pattern cause short circuits of the copper pattern circuit, and thus cause a failure of the entire apparatus. In connection with such a problem, in the prior art, the flexible printed cable was formed in a double structure as one method for preventing stress concentration occurring in the flexible printed cable.

3 is a schematic cross-sectional view of a flexible printed cable formed of a dual structure.

Referring to the drawings, the flexible printed cable covers the first base film 31, the first copper pattern 32 formed on the first base film 31, and the first copper pattern 32. The first cover film 33 is provided. The first cover film 33 is attached to the upper surface of the first base film 33 by an adhesive 34.

On the other hand, the second base film 31 ′ is provided on the rear surface of the first base film 31. A second copper pattern 32 ′ is formed on the second base film 31 ′, and the second cover film 33 ′ uses an adhesive 34 ′ to protect the second copper pattern 31 ′. It is attached to the second base film 33 'through. The first base film 31 and the second base film 31 ′ are attached to each other by an adhesive 35. The adhesive 35 is applied only to a part of the width of the base films 31 and 31 'so that an air layer is formed between the base films 31 and 31' at the other part.

Despite the advantage that the flexibility and durability of the flexible printed cable having a cross-sectional structure as shown in FIG. 3 can be improved, there is a problem in that it is difficult to apply due to the disadvantage of high manufacturing cost. In addition, there is a problem that the two base films 31 and 31 'increase the thickness of the entire cable.

Shown in FIG. 4 is a cross-sectional view of another example flexible printed cable according to the prior art, which is referred to as a two metal flexible printed cable.

Referring to the drawings, first and second copper patterns 42 and 42 'are formed on the upper surface and the lower surface of the base film 41, respectively, and cover the first and second copper patterns 42. The cover films 43 and 43 'are attached to the base film 41 through the adhesives 44 and 44' so as to be protected. Compared with the example shown in FIG. 3, it can be understood that a copper pattern is formed on the upper and lower surfaces thereof while sharing the base film 41.

In the flexible printed cable as shown in Fig. 4, the base film 41 is made of polyimide material, and the thickness a is 25 micrometers. In addition, the copper patterns 42 and 42 'have a thickness b of 30 micrometers, and are usually formed through electroplating to obtain a predetermined thickness. On the other hand, the adhesive 44 has a thickness of 25 micrometers, and the thickness c of the lid film 43 made of polyimide has 12.5 micrometers.

When the flexible printed cable shown in FIG. 4 is applied to a rotating component as shown in FIG. 1, there is a problem that cracks often occur in the copper patterns 42 and 42 'due to repeated bending of the cable. . According to the applicant's experiment, if the camera 13 is rotated more than 13,000 times in the camera phone, a crack is generated, resulting in a short of the flexible printed cable.

 The present invention has been made to solve the above problems, it is an object of the present invention to provide an improved flexible printed cable.                         

Another object of the present invention is to provide a flexible printed cable with improved flexibility.

Another object of the present invention is to provide a flexible printed cable which can prevent occurrence of a short circuit due to a crack on the copper pattern.

In order to achieve the above object, according to the present invention,

With base film,

First and second copper patterns formed on the first surface and the second surface of the base film,

A flexible printed cable comprising a first surface of the base film 51 and a first cover film and a second cover film adhered to each other by an adhesive layer on a second surface to cover the copper pattern.

The thickness of the base film and the thickness of the first and second cover films are each 12.5 micrometers,

A flexible printed cable is provided, wherein the thickness of the first and second copper patterns is 18 micrometers.

According to one feature of the invention, the first and second copper patterns are formed on the first and second surfaces of the base film by lamination.

According to another feature of the invention, the thickness of the adhesive layer is 15 micrometers.

Also according to the invention,                     

With base film,

A first copper pattern and a second copper pattern each formed on one surface and a second surface of the base film,

A flexible printed cable having a connection portion interconnecting the first copper pattern and the second copper pattern by being filled in a hole formed in the base film,

The thickness of the first copper pattern and the second copper pattern is each 18 micrometers,

A flexible printed cable is provided, wherein the connection portion has a thickness of 30 micrometers from the surface of the base film at a hole formed in the base film.

According to another feature of the invention, the first copper pattern and the second copper pattern is formed by lamination, the connecting portion is formed by electroplating.

Hereinafter, with reference to an embodiment shown in the accompanying drawings the present invention will be described in more detail.

According to the inventor's experiment, it is preferable that the bending radius of the bend is as large as possible in the area where the flexible printed cable is bent so that the crack does not occur in the repeated bending action of the flexible printed cable. It is desirable that the thickness of the cable be as thin as possible.

More specifically, in the case of applying the flexible printed cable to the camera phone as shown in FIG. 1, the flexible printed cable 14 is connected to the camera 13 in order to be connected to the camera 13. Precisely, the camera is bent around a cylindrical barrel (not shown) of the camera, which radius of curvature was conventionally about 0.8 mm. Experiments show that by increasing the radius of curvature of this bend, the likelihood of cracking is reduced. Thus, bending can increase the radius of curvature to preferably 1.25 mm. However, it is true that the bending radius of bending generated when the flexible printed cable is connected to an electronic component or a circuit board is a design value that can be changed according to the arrangement of the component and the circuit.

On the other hand, the inventors of the present invention have found that the occurrence of cracks can be prevented by reducing the thickness of the printed flexible cable. This is believed to be because the flexibility is increased by reducing the thickness of the cable, and the increase in flexibility reduces the possibility of cracking. Therefore, by reducing the thickness of each material constituting the flexible printed cable, the overall flexibility of the cable can be increased, and in particular, simply reducing the thickness of the base film can improve the flexibility of the cable to prevent the occurrence of cracks. have.

5 is a schematic cross-sectional view of an embodiment of a printed flexible cable according to the present invention, which corresponds to the cross-sectional structure of the conventional cable shown in FIG.

Referring to the drawings, the overall cross-sectional structure of the printed flexible cable according to the present invention is generally similar to the cable shown in FIG. That is, the printed flexible cable includes a base film 51, first and second copper patterns 52 and 52 ′ formed on the first surface and the second surface of the base film 51, and the copper. First and second cover films 53 and 53 bonded through the adhesive layers 54 and 54 'on the first and second surfaces of the base film 51 to cover the patterns 52 and 52', respectively. '). Preferably, the base film 51 and the first and second cover films 53 and 53 'are made of a polyimide (PI) material.

According to one feature of the present invention, the thickness d of the base film 51 is formed at 12.5 micrometers, and the thickness f of the first and second cover films 53 and 53 'is also 12.5 microns. It is formed in meters. The thickness of each of these films is greatly reduced by the prior art, which improves the flexibility of the flexible printed cable, thereby preventing cracks that may occur in the first and second copper patterns 52, 52 '. can do. It is also preferable that the thicknesses of the adhesive layers 54, 54 'are each 15 micrometers.

On the other hand, by reducing the thickness of the first and second copper patterns 52 and 52 ', flexibility of the cable can be improved. However, it should be taken into account that the reduction in the thickness of the copper pattern leads to the reduction in the cross-sectional area of the copper pattern, thus leading to increased resistance in current conduction. Preferably, the thickness of the first and second copper patterns 52, 52 'is 18 micrometers, respectively, and is preferably formed only by lamination and etching methods, excluding formation by electroplating or electroless plating. That is, the copper thin film is formed by lamination, and then a mask of the photoresist is formed by application, exposure, and development of the photoresist, and the copper thin film is etched with an etching solution, thereby completing a predetermined pattern.

Since the first and second copper patterns 52 and 52 ′ are formed on both surfaces of the base film 51, various advantages may be obtained. For example, by making one of the two copper patterns serve as a dummy pattern, the rigidity of the copper pattern can be reinforced. In another example, when the number of conductive lines included in the cable is increased, use of both surfaces of the base film may maximize utilization of a narrow area.

Shown in Figure 6 is a schematic cross-sectional view of another part of a flexible printed cable according to the present invention.

Referring to the drawings, this is the first copper pattern 62 is formed on the first surface of the base film 61, the second copper pattern 62 'is formed on the second surface 63. In FIG. 6, the cover film used for protecting the copper patterns 62 and 62 ', and the adhesive layer for attaching it are omitted. As can be seen in the figure, the copper pattern 62 formed on the first surface is formed over the entire first surface of the cable, i.e. over the entire width of the printed flexible cable as shown in FIG. In contrast, the copper pattern 62 'formed on the second surface of the cable is formed over a portion of the width of the cable. The first copper pattern 62 and the second copper pattern 62 'are formed through the plating by lamination, as described above, excluding the formation by electroplating or electroless plating, and the respective copper patterns 62, The thickness of the thickness m of 62 ') is preferably 18 micrometers.

Meanwhile, the first copper pattern 62 and the second copper pattern 62 ′ are connected through the holes 61a formed in the base film 61. That is, the first copper pattern 62 and the second copper pattern 62 'formed on both surfaces of the base film 61 are formed by forming the connecting portion 65 with the copper material in the hole 61a of the base film 61. It can be connected to each other.

Filling the inner surface of the hole 61a formed in the base film 61 with a copper material is not possible by the same method as lamination, and is preferably made by electroplating. When the copper material is filled in the hole 61a using electroplating, the thickness n of the connection portion 65 from the surface of the base film 61 at the portion where the hole 61a is formed corresponds to 30 micrometers. something to do. The thickness of the base film 61 is preferably 12.5 micrometers as described with reference to FIG. 5.

By forming the pattern by performing electroplating only on the portion where the hole 61a is formed in the base film 61 as described above, the thickness of the flexible printed cable is reduced as compared with the prior art as a whole except for the portion where the hole is formed. This increases the flexibility of the cable and significantly reduces the likelihood of cracking in the copper pattern even when bending stress is applied to the cable. When plating the hole 61a of the base film 61, a seed material for electroplating is introduced into the inner surface of the hole 61a and then electroplated, or in other examples, electroless plating may be performed. It may be.

The necessity of forming holes 61a in the base film 61 to connect the first copper pattern 62 and the second copper pattern 62 'may be due to various reasons. For example, when it is necessary to connect a specific conductive line of the first copper pattern 62 to a specific conductive line of the second copper pattern 62 ', the holes 61a can be formed to form the connecting portion 65. have. In another example, the contact area of the connector is enlarged by connecting some of the conductive lines of the first copper pattern 62 to the second copper pattern 62 'in order to enlarge the area of the connector forming the terminal of the cable. . In addition, the connection part 65 and the hole 61a may be used by various needs.

The flexible printed cable according to the present invention has the advantage of improving flexibility by reducing the overall thickness and thus reducing the stress on the copper pattern to reduce the possibility of cracking. Thus, the flexible printed cable according to the present invention is significantly reduced in the possibility of cracking in the copper pattern even if it is connected to a circuit board or a component in which repeated bending motion occurs.

According to the experiments of the present inventors, in the case of the flexible printed cable according to the prior art, cracks occurred in the copper pattern in 13,000 repetitive bending motions, but the flexible printed cable as described with reference to FIG. 5 of the present invention is applied. This prevents cracking in the copper pattern even after 80,000 repeated bending movements.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is only illustrative, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Could be. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (5)

With base film, First and second copper patterns formed on the first surface and the second surface of the base film, A flexible printed cable comprising a first surface of the base film 51 and a first cover film and a second cover film adhered to each other by an adhesive layer on a second surface to cover the copper pattern. The thickness of the base film and the thickness of the first and second cover films are each 12.5 micrometers, Flexible printed cable, characterized in that the thickness of the first and second copper patterns is 18 micrometers. The method of claim 1, And the first and second copper patterns are formed on the first and second surfaces of the base film by lamination. The method of claim 1, The thickness of the adhesive layer is a flexible printed cable, characterized in that 15 micrometers. With base film, A first copper pattern and a second copper pattern each formed on one surface and a second surface of the base film, A flexible printed cable having a connection portion interconnecting the first copper pattern and the second copper pattern by being filled in a hole formed in the base film, The thickness of the first copper pattern and the second copper pattern is each 18 micrometers, Flexible printed cable, characterized in that the thickness of the connecting portion from the surface of the base film at the site where the hole is formed in the base film is 30 micrometers. The method of claim 4, wherein The first copper pattern and the second copper pattern is formed by lamination, and the connecting portion is formed by electroplating flexible printed cable.

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