KR20140095207A - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device and, in particular, to a liquid crystal display device for preventing bending of a flexible printed circuit (FPC). A feature of the present invention is to attach a flexible film on an upper part of a second coverlay which is the opposite side of the direction in which FPC outputting various types of signal voltages for operating a liquid crystal panel is bended along at least one edge of the liquid crystal panel. By this, bending of the FPC in the opposite direction can be prevented, so that process errors reducing the productivity due to malfunction of a module mounting process or test process of the liquid crystal panel can be prevented. Also, a disconnection error of FPC caused by weak bonding force of ACF which is a connection part of the FPC and liquid crystal panel can be prevented. In addition, the flexible film can prevent the bonding force of FPC during a process of bonding FPC on a first substrate, from becoming weak by bonding the FPC to the first substrate and attaching the same to the upper part of the first coverlay. Moreover, there is no need to coat separate UV resin between the first coverlay and first substrate used for preventing bending of the FPC in the opposite direction, therefore a separate process for coating UV resin can be emitted, thereby improving the effectiveness of the process.

Description

[0001] Liquid crystal display device [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device for preventing warpage of an FPC (flexible printed circuit).

A liquid crystal display device (LCD), which is advantageous for moving picture display and has a large contrast ratio and is actively used in TVs and monitors, exhibits optical anisotropy and polarization properties of a liquid crystal, And the like.

Such a liquid crystal display device has a liquid crystal panel in which a liquid crystal panel is interposed between two adjacent substrates through a liquid crystal layer as an essential component and changes the alignment direction of the liquid crystal molecules in an electric field in the liquid crystal panel to realize a difference in transmittance do.

However, since the liquid crystal panel does not have its own light emitting element, a separate light source is required to display the difference in transmittance as an image. To this end, a backlight having a light source is disposed on the back surface of the liquid crystal panel.

1 is a schematic perspective view of a general liquid crystal panel.

As shown in the figure, a general liquid crystal panel 10 is a part that plays a key role in image display, and is composed of first and second substrates 12 and 14 which are bonded together with a liquid crystal layer interposed therebetween.

A flexible cable 17 such as a flexible printed circuit (FPC) that outputs various signal voltages for driving the liquid crystal panel 10 along at least one edge of the first substrate 12 of the liquid crystal panel 10 (Hereinafter, referred to as an FPC) is closely connected to the back surface of the liquid crystal panel 10 by being properly bent during the modularization process.

At this time, the liquid crystal panel 10 and the FPC 17 are connected to each other via an anisotropic conductive film (not shown) (hereinafter referred to as ACF) which is a conductive adhesive material.

However, the liquid crystal panel 10 to which the FPC 17 is connected has some problems.

As shown in FIG. 2, when the FPC 17 is warped in the reverse process of the FPC 17 in the process of modulating the liquid crystal panel 10, The test process or the module mounting process of the semiconductor device 10 does not progress smoothly, which leads to poor processability in which mass productivity is degraded.

A crack in the FPC 17 is generated by the bending of the FPC 17 or a bending force of the ACF which is the connection part between the liquid crystal panel 10 and the FPC 17 due to the backward bending of the FPC 17 And the defect of disconnection of the FPC 17 frequently occurs. As a result, a driving operation failure of the liquid crystal panel 10 occurs, or the circuit portion is damaged.

This causes the reliability of the liquid crystal display device to deteriorate.

SUMMARY OF THE INVENTION It is a first object of the present invention to prevent the reverse bending of the FPC from occurring.

It is a second object of the present invention to prevent a driving failure of the liquid crystal panel from occurring, and it is a third object of the present invention to improve the reliability of the liquid crystal display device.

According to an aspect of the present invention, there is provided a liquid crystal display comprising: a liquid crystal panel having first and second substrates bonded together; A flexible printed circuit (FPC) disposed along at least one edge of the first substrate, the flexible printed circuit (FPC) being extended to a back surface of the first substrate; And a flexible film attached to an upper surface of the FPC opposite to a rear surface of the first substrate facing the rear surface.

At this time, the flexible film may be formed of a polymer such as capton, polyethersulphone (PES), polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate wherein the flexible film comprises one or more materials selected from polyethylenenaphthalate (PEN), polyacrylate (PAR), and fiber reinforced plastic (FRP) And a capton tape coated with a pressure-sensitive adhesive.

The flexible film has a tension of 120 gf to 200 gf, and the flexible film has a thickness of 0.02 to 0.2 mm.

Here, the flexible film is attached through an adhesive material made of acrylic or silicone resin. The FPC includes a power wiring layer contacting with the first substrate through an ACF, a base film provided on one surface of the power wiring layer, And a cover layer provided on the other surface of the power supply wiring layer. The first and second cover rails are respectively attached to the base film and the cover layer.

At this time, the first and second cover rails are overlapped and attached to each other, and the flexible film is attached to the upper portion of the second cover ray.

As described above, according to the present invention, in the flexible printed circuit (FPC) that outputs various signal voltages for driving the liquid crystal panel along at least one edge of the liquid crystal panel, the upper surface of the second cover It is possible to prevent the FPC from being warped in the reverse direction by attaching the flexible film to the upper portion of the ray and the test process or the module mounting process of the liquid crystal panel is not smoothly progressed , It is possible to prevent the occurrence of poor processability in which the productivity is lowered and also the bonding force of the ACF which is the connecting portion of the liquid crystal panel and the FPC is weakened and the occurrence of the defect of disconnection of the FPC can be prevented .

As a result, it is possible to prevent the driving failure of the liquid crystal panel from occurring, and finally, the reliability of the liquid crystal display device is improved.

Further, the flexible film may be formed by bonding the FPC on the first substrate and then attaching the FPC on the first cover layer, thereby preventing the bonding force of the FPC from being weakened in the process of bonding the FPC onto the first substrate Since it is unnecessary to apply a separate UV resin between the first cover layer and the first substrate in order to prevent the flexure of the FPC in the reverse direction, it is possible to omit a separate process for applying the UV resin, thereby improving the process efficiency There is an effect that can be made.

1 is a schematic perspective view of a general liquid crystal panel.
FIG. 2 is a perspective view schematically showing a state in which reverse bending of the FPC occurs. FIG.
3 is an exploded perspective view schematically showing a liquid crystal display device according to an embodiment of the present invention.
4 is a perspective view schematically showing a structure of an FPC according to an embodiment of the present invention.
5 is a perspective view schematically showing a state in which the FPC of the present invention is prevented from being warped in a reverse direction.
6 is an experimental graph illustrating crack rigidity of an FPC according to an embodiment of the present invention.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

3 is an exploded perspective view schematically showing a liquid crystal display device according to an embodiment of the present invention.

1, the liquid crystal display includes a liquid crystal panel 110, a backlight unit 120, a support main body 130 for modularizing the liquid crystal panel 110 and the backlight unit 120, a cover bottom 150, (140).

The liquid crystal panel 110 is a part that plays a key role in image display and includes a first substrate 112 and a second substrate 114 which are bonded to each other with a liquid crystal layer interposed therebetween, .

At this time, a plurality of gate lines and data lines intersect to define the pixels on the inner surface of the first substrate 112, which is usually referred to as a lower substrate or an array substrate, although not shown in the drawing, A thin film transistor (TFT) is provided at each intersection and is connected in one-to-one correspondence with the transparent pixel electrode formed in each pixel.

On the inner surface of the second substrate 114 called an upper substrate or a color filter substrate, color filters of red (R), green (G), and blue (B) And a black matrix for covering non-display elements such as a gate line, a data line, and a thin film transistor. In addition, a transparent common electrode covering these elements is provided.

A polarizing plate (not shown) for selectively transmitting only specific light is attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

A film on glass (FOG) mounting method in which a flexible printed circuit board is directly bonded to a liquid crystal panel along at least one edge of the liquid crystal panel 110 is bonded via an anisotropic conductive film (not shown) And a flexible printed circuit (FPC) 170 for outputting various signal voltages.

A plurality of wiring patterns (not shown) and driving elements (not shown) are aligned and mounted on the FPC 170, and the FPC 170 is folded back to the back surface of the liquid crystal panel 110 in the modularization process.

Here, the characteristic feature of the present invention is that when the upper surface of the FPC 170, that is, one surface facing the direction in which the FPC 170 is tilted toward the back surface of the liquid crystal panel 110 is defined as a back surface, And the film 180 is attached.

Therefore, the FPC 170 of the present invention can prevent the FPC 170 from being bent in the reverse direction opposite to the direction in which the FPC 170 is bent toward the back surface of the liquid crystal panel 110, the test process or the module mounting process can be prevented from proceeding smoothly and the manufacturing process failure in which the mass productivity is lowered can be prevented from occurring. Further, cracks and liquid crystals of the FPC 170, The bonding force of the ACF 160 (see FIG. 4), which is the connecting portion between the panel 110 and the FPC 170, is weakened, thereby preventing the occurrence of disconnection failure of the FPC 170.

Let's take a closer look at this later.

When the thin film transistor selected for each gate line is turned on by the on / off signal of the gate driving circuit, the liquid crystal panel 110 to which the FPC 170 is connected turns on the signal voltage of the data driving circuit through the data line, And the alignment direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode, thereby exhibiting a difference in transmittance.

In the liquid crystal display device according to the present invention, a backlight unit 120 is provided to supply light from the rear surface of the liquid crystal display panel so that a difference in transmittance of the liquid crystal panel 110 is manifested to the outside.

The backlight unit 120 includes an LED assembly 129, a white or silver reflective plate 125, a light guide plate 123 seated on the reflective plate 125, and an optical sheet 121 interposed therebetween .

The LED assembly 129 is disposed on one side of the light guide plate 123 so as to face the light incident surface of the light guide plate 123. The LED assembly 200 includes a plurality of LEDs 129a, And an LED FPCB (flexible printed circuit board) 129b which is mounted separately.

The light guiding plate 123 through which the light emitted from the plurality of LEDs 129a of the LED assembly 129 is incident is formed such that the light incident from the LED 129a travels through the light guiding plate 123, ) To provide a surface light source to the liquid crystal panel 110. [

The light guide plate 123 may include a pattern of a specific pattern on the back surface to supply a uniform surface light source.

The reflection plate 125 is disposed on the back surface of the light guide plate 123 and reflects light passing through the back surface of the light guide plate 123 toward the liquid crystal panel 110 to improve the brightness of light.

The optical sheet 121 on the light guide plate 123 includes a diffusion sheet and at least one light condensing sheet and diffuses or condenses the light passing through the light guide plate 123 to provide a more uniform surface light source to the liquid crystal panel 110 Let it enter.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the top cover 140, the guide panel 130 and the cover bottom 150. The top cover 140 is disposed on the top edge of the liquid crystal panel 110, So as to cover the side surface.

Here, the top cover 140 has a rectangular frame shape bent in a "? &Quot; shape so as to cover the top and side edges of the liquid crystal panel 110, As shown in Fig.

In addition, the cover bottom 150, on which the liquid crystal panel 110 and the backlight unit 120 are mounted and which is the basis for assembling the entire apparatus of the liquid crystal display apparatus, is composed of a horizontal plane and an edge portion whose edge is vertically bent.

A rectangular guide panel 130 mounted on the cover bottom 150 and covering the edges of the liquid crystal panel 110 and the backlight unit 120 includes a top cover 140 and a cover bottom 150, .

Here, the top cover 140 may be referred to as a case top or a top case, and the guide panel 130 may be referred to as a support main or a main support or a mold frame. The cover bottom 150 may be referred to as a bottom cover or a bottom cover I will.

Recently, in order to realize a lightweight and thin liquid crystal display device, the top cover 140 and the cover bottom 150 are removed, and the liquid crystal panel 110 and the backlight 150 are fixed to each other through the adhesive tape (not shown) The unit 120 may be integrally modularized. This can also reduce material costs.

In this case, the backlight unit 520 having the above-described structure is generally called a side light type, and a direct light (LED) light source is used in which a plurality of LED assemblies 129 are arranged in parallel to the upper front surface of the reflection plate 125 ), And in the case of the direct light type, the light guide plate 123 may be omitted.

The LED FPCB 129b of the LED assembly 129 may be omitted and a plurality of LEDs 129a may be mounted at a predetermined distance along one edge of the FPC 170. The FPC 170 may be mounted on the liquid crystal panel 110 The plurality of LEDs 129a mounted on the FPC 170 may be formed to face the light incident surface of the light guide plate 123. In this case,

Therefore, it is not necessary to provide a separate LED PCB 129b for mounting a plurality of LEDs 129a, thereby reducing the process cost through elimination of the LED PCB 129b, The thickness and weight of the LED PCB 129b of the liquid crystal display device can be reduced by the thickness and weight.

The liquid crystal display of the present invention may be configured such that the flexible film 180 is attached to one surface of the FPC 170 that outputs various signal voltages of the liquid crystal panel 110 so that the deflection of the FPC 170 in the opposite direction It is possible to prevent the test process or the module mounting process of the liquid crystal panel 110 from progressing smoothly and to prevent the occurrence of a process failure in which the mass productivity is lowered, And the bonding force between the crack of the FPC 170 and the ACF 160 (see FIG. 4), which is the connecting portion between the liquid crystal panel 110 and the FPC 170, is weakened to cause the defect of disconnection of the FPC 170 Can be prevented.

4 is a perspective view schematically showing the structure of an FPC according to an embodiment of the present invention.

As shown in the figure, the first substrate 112 of the liquid crystal panel 110 in which the first and second substrates 112 and 114 are attached is further provided with a pad region as compared with the second substrate 114, The larger the area of the area.

Therefore, a driving circuit (not shown) for applying a signal to a plurality of gate lines and data lines is formed as a pad region which is one edge of the first substrate 112, and a driving circuit And a flexible printed circuit (FPC) 170 for outputting various signal voltages for driving are connected.

Here, the FPC 170 includes a base film 171 having a flexible characteristic, a power wiring layer 173 formed of a plurality of metal wirings formed by patterning a conductive material in a lower portion of the base film 171, A cover layer 175 is formed as an organic or inorganic insulating material for protecting the insulating layer 173.

The base film 171 serves to mount and support the power supply wiring layer 173 and the cover layer 175 in the lower part thereof.

The base film 171 and the cover layer 175 may be made of a resin material such as polyimide or polyester to maintain an electrical insulation state. Is formed in a film form by receiving a relatively good polyimide.

A portion of the cover layer 175 is removed and the exposed power wiring layer 173 is electrically connected to a plurality of pads (not shown) of a driving circuit (not shown) formed on the first substrate 112 via the ACF 160 And are attached to each other.

The FPC 170 of the present invention is formed by overlapping first and second cover layers 177a and 177b on the cover layer 175 and the base film 171, The rigidity of the endless belt is improved.

In particular, the FPC 170 of the present invention can prevent the flexure of the FPC 170 in the reverse direction by further attaching the flexible film 180 to the upper portion of the second coverlay 177b.

That is, the FPC 170 is formed by being bent to the back surface of the liquid crystal panel 110, that is, the back surface of the first substrate 112 in the modularization process of the liquid crystal panel 110. At this time, The flexible film 180 is attached to the upper portion of the second coverlay 177b on the upper surface of the FPC 170 to prevent the FPC 170 from being bent in the reverse direction.

Therefore, it is possible to prevent the process step failure (test process or module mounting process) of the liquid crystal panel 110 from progressing smoothly, which leads to a decrease in mass productivity, It is possible to prevent the bonding strength of the ACF 160, which is the connecting portion between the panel 110 and the FPC 170, from weakening.

Here, the flexible film 180 may be formed of a material such as capton, polyethersulphone (PES), polycarbonate (PC), polyimide (PI), polyethyleneterephthalate (PET) And a material selected from the group consisting of polyethylenenaphthalate (PEN), polyacrylate (PAR), and fiber reinforced plastic (FRP).

Here, it is preferable that the flexible film 180 is made of a capimeter tape having excellent heat resistance, chemical resistance, and withstanding voltage resistance in the form of a polyimide film coated with a silicone adhesive.

The flexible film 180 preferably has a tension of 120 gf to 200 gf and is formed to have a thickness of 0.02 to 0.2 mm, more preferably 0.05 to 0.175 mm.

The flexible film 180 is attached to an upper portion of the second cover lay 177b through an adhesive material (not shown) made of an acrylic or silicone resin having adhesive properties and permeability.

Therefore, it is possible to prevent the FPC 170 of the present invention from being bent in the reverse direction.

Therefore, it is possible to prevent the process step failure (test process or module mounting process) of the liquid crystal panel 110 from progressing smoothly, which leads to a decrease in mass productivity, It is possible to prevent the bonding strength of the ACF 160, which is the connecting portion between the panel 110 and the FPC 170, from weakening.

In particular, the flexible film 180 may be formed by bonding the FPC 170 on the first substrate 112 and then attaching the FPC 170 on the second coverlay 177b, The bonding force of the FPC 170 can be prevented from being weakened.

That is, after the ACF 160 is interposed between the first substrate 112 and the FPC 170, the FPC 170 applies heat and pressure from the upper portion of the FPC 170, The ACF 160 interposed between the FPC 170 and the first substrate 112 may be used when the thickness of the FPC 170 is increased to prevent the FPC 170 from being warped in the reverse direction. The losing heat and pressure are weakened and the bonding force of the ACF 160 is lowered.

Accordingly, the bonding force between the FPC 170 and the first substrate 112 is weakened.

On the other hand, the FPC 170 of the present invention bonds the FPC 170 onto the first substrate 112, and then the flexible film 180 is transferred onto the second coverlay 177b of the FPC 170 It is possible to prevent the bending of the FPC 170 in the reverse direction and prevent the bonding force of the ACF 160 between the FPC 170 and the first substrate 112 from being lowered even if the FPC 170 is not formed thickly, You can do it.

The FPC 170 of the present invention can prevent the flexure of the FPC 170 from being bent in the reverse direction through the flexible film 180, It is not necessary to apply a separate UV resin (not shown) between the substrate 112 and the substrate 112, so that a separate process for applying the UV resin (not shown) can be omitted, and the efficiency of the process can be improved.

5 is a perspective view schematically showing a state in which the FPC of the present invention is prevented from being warped in a reverse direction.

As shown in the figure, the second coverlay 177b of the FPC 170, which is composed of the base film 171, the power supply wiring layer 173, the cover layer 175 and the first and second coverlayers 177a and 177b, By further attaching the flexible film 180 to the upper portion of the FPC 170, a repulsive force is generated by the flexible film 180 in the opposite direction when the flexure occurs in the reverse direction of the FPC 170.

Therefore, it is possible to prevent the FPC 170 of the present invention from being bent in the reverse direction.

Table 1 below shows the results of an experiment for measuring the crack rigidity of the FPC 170 according to the embodiment of the present invention, and FIG. 6 is a graph of the table (1).

No Sample 1 Sample 2 Sample 3 Sample 4 One 5 times NG 25 times NG 80 times NG 60 times NG 2 5 times NG 30 times NG 50 times NG 80 times NG 3 10 times NG 30 times NG 50 times NG 50 times NG 4 10 times NG 25 times NG 70 times NG 50 times NG 5 10 times NG 15 times NG 80 times NG 50 times NG Average 8 25 66 58

The experiment of Table 1 and FIG. 6 demonstrates that the FPC 170 bonded on the first substrate 112 of the liquid crystal panel 110 is pulled in parallel along the longitudinal direction of the FPC 170 while flexing in the opposite direction .

Here, Sample 1 is a general FPC having no configuration for preventing the FPC from being warped, Sample 2 is a configuration in which first and second cover rails are overlapped with each other in the FPC, and Sample 3 is an example of the present invention The first and second cover rails are formed so as to overlap with each other, and a flexible film is attached to the upper surface of the second cover lay. Sample 4 is formed to overlap the first and second cover rails on the FPC, And a UV resin is applied between the first substrate and the first coverlay.

Referring to Table 1 and the graph of FIG. 6, it can be seen that NG occurs when Sample 3 reproduces the bending in the reverse direction on the FPC over an average of 66 times. This indicates that NG of Sample 1, Sample 2, Sample 4 It can be confirmed that the number is higher than the number of occurrences.

That is, in the case of the sample 1 having no bending prevention structure of the separate FPC, the FPC is cracked when the bending occurs in the opposite direction 8 times, and the sample 2 formed so that the first and second coverlay are overlapped with each other is 25 When the bending of the reverse direction of the meeting occurs, a crack of the FPC occurs.

In the case of the FPC including the first and second cover rails and the UV resin of Sample 4, when the deflection occurs on the average of 58 times in the reverse direction, the FPC crack occurs. However, according to the embodiment of the present invention, In case of Sample 3 including 2 cover rails and flexible film, an FPC crack occurs only when an average of 66 deflections occur in the reverse direction.

This means that the FPC of the present invention as Sample 3 has a much higher rigidity than other FPCs, and it is possible to prevent the reverse bending of the FPC from occurring due to the high rigidity .

Therefore, it is possible to prevent the process step failure (test process or module mounting process) of the liquid crystal panel 110 from progressing smoothly, which leads to a decrease in mass productivity, It is possible to prevent the bonding strength of the ACF 160, which is the connecting portion between the panel 110 and the FPC 170, from weakening.

The flexible film 180 may be formed on the first substrate 112 by bonding the FPC 170 on the first substrate 112 and then attaching the FPC 170 on the second coverlay 177b. It is possible to prevent the bonding force of the FPC 170 from being weakened in the process of bonding the first cover layer 177a and the first substrate 112 to each other. In order to prevent the FPC 170 from being warped in the reverse direction, Since it is not necessary to apply the UV resin (not shown), a separate step for coating the UV resin (not shown) can be omitted, and the efficiency of the process can be improved.

The liquid crystal display according to the exemplary embodiment of the present invention includes the FPC 170 of the FPC 170 that outputs various signal voltages for driving the liquid crystal panel 110 along at least one edge of the liquid crystal panel 110 It is possible to prevent the flexure in the reverse direction of the FPC 170 from being caused by attaching the flexible film 180 to the upper portion of the second coverlay 177b on the upper surface opposite to the direction in which the FPC 170 is tilted.

This prevents the test process or the module mounting process of the liquid crystal panel 110 from progressing smoothly, thereby preventing a process failure in which the mass productivity is lowered, The bonding force of the ACF 160, which is the connecting portion between the liquid crystal panel 110 and the FPC 170, is weakened, thereby preventing the disconnection failure of the FPC 170 from occurring.

The flexible film 180 may be formed on the first substrate 112 by bonding the FPC 170 on the first substrate 112 and then attaching the FPC 170 on the second coverlay 177b. It is possible to prevent the bonding force of the FPC 170 from being weakened in the process of bonding the first cover layer 177a and the first substrate 112 to each other. In order to prevent the FPC 170 from being warped in the reverse direction, Since it is not necessary to apply the UV resin (not shown), a separate step for coating the UV resin (not shown) can be omitted, and the efficiency of the process can be improved.

The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

110: liquid crystal panel (112: first substrate, 114: second substrate)
160: ACF
170: FPC (171: base film, 173: power wiring layer, 175: cover layer, 177a, 177b: first and second coverlay)
180: Flexible film

Claims (9)

A liquid crystal panel to which the first and second substrates are bonded;
A flexible printed circuit (FPC) disposed along at least one edge of the first substrate, the flexible printed circuit (FPC) being extended to a back surface of the first substrate;
A flexible film attached to an upper surface of the FPC opposite to a back surface of the first substrate,
And the liquid crystal display device.
The method according to claim 1,
The flexible film may be formed of a material selected from the group consisting of Kapton, polyethersulphone (PES), polycarbonate (PC), polyimide (PI), polyethyleneterephthalate (PET), polyethylenenaphthalate PEN), polyacrylate (PAR), and fiber reinforced plastic (FRP).
The method according to claim 1,
Wherein the flexible film comprises a capton tape coated with a silicone adhesive on a film made of the polyimide.
The method according to claim 1,
Wherein the flexible film has a tension of 120 gf to 200 gf.
The method according to claim 1,
Wherein the flexible film has a thickness of 0.02 to 0.2 mm.
The method according to claim 1,
Wherein the flexible film is attached through an adhesive material comprising acrylic or silicone resin.
The method according to claim 6,
The FPC includes a power wiring layer contacting with the first substrate through an ACF, a base film provided on one surface of the power wiring layer, and a cover layer provided on the other surface of the power wiring layer, And the first and second cover rails are attached to the upper portion of the layer.
8. The method of claim 7,
Wherein the first and second cover rails are overlapped and attached to each other.
8. The method of claim 7,
And the flexible film is attached to the upper portion of the second coverlay.

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