KR101852998B1 - Flexible printed circuit for liquid crystal display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device, and more particularly, to an FPC for a liquid crystal display device capable of increasing the efficiency of a soldering process through a via hole.
A feature of the present invention is that via holes in which lands of the input / output pads of the FPC are formed are shifted from each other, or via holes are formed at the edges of the input / output pads.
As a result, it is possible to prevent the occurrence of defective soldering such as cold soldering or non-soldering, and to reduce the interval between the input / output pads of the FPC and to prevent defective connection of the FPC. Therefore, it is possible to prevent the driving operation failure of the liquid crystal panel or the circuit portion from being damaged.
Further, by improving the connection force between the pad and the first and second signal pads, the FPC, the control printed circuit board, and the data printed circuit board can be stably fixed to each other.

Description

[0001] The present invention relates to a flexible printed circuit board for a liquid crystal display,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device, and more particularly, to an FPC for a liquid crystal display device capable of increasing the efficiency of a soldering process through a via hole.

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.

Such a liquid crystal display device is usually driven by providing a driving signal required for driving the liquid crystal panel to a liquid crystal panel through a printed circuit board (PCB) on which a driving circuit is mounted. At this time, electrical connection between the printed circuit board and the liquid crystal panel may be performed by a flexible printed circuit (FPC).

The FPC includes a signal supply unit such as a plurality of conductive lines and pads for electrically connecting the printed circuit board and the liquid crystal panel.

In the signal supply unit, the width and interval between the signal supply unit and the liquid crystal display unit are gradually reduced as the liquid crystal display unit is moved to a higher resolution. When the width of the signal supply unit is reduced, the signal supply unit is required for the soldering process for connection between the signal supply unit and the printed circuit board or the liquid crystal panel The width of the via hole should also be reduced.

When the width of the via hole is not reduced, the width of the signal supplying portion with respect to the via hole is narrowed, and the signal supplying portion is opened.

However, if the size of the via hole is reduced, the solder (lead) does not come in between the via holes, resulting in the problem of cold storage or non-storage.

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 provide an FPC and a liquid crystal display device including the same that can increase the efficiency of a soldering process through a via hole.

A second object of the present invention is to improve the reliability of the liquid crystal display device.

In order to achieve the above object, the present invention provides a semiconductor device comprising: an input pad and an output pad connected to a signal pad of a printed circuit board; And a via hole formed in the input pad and the output pad, the via hole being formed to be offset from the adjacent input pad and output pad, respectively.

At this time, the via holes are arranged in a zigzag shape, and when the input pad and the output pad are connected to the signal pads by soldering, solder is filled in the via hole.

In addition, a land is formed around the via hole so that the width of the pad is wider than other regions, and the distance between the via holes is 300 to 1000 占 퐉.

The present invention also relates to an electronic device comprising: an input pad and an output pad connected to a signal pad of a printed circuit board; And a via hole formed in the input pad and the output pad and formed in the shape of a groove along the longitudinal edge of the input pad and the output pad, respectively.

In this case, the via hole is formed at two opposing edges of the input pad and the output pad, and two via holes are formed at one edge of the input pad and the output pad, and the via holes formed at the opposite edges of the input pad and the output pad are formed to be shifted from each other.

Each end of the input pad and the output pad is formed as a groove.

According to the present invention, by forming the via-holes in which the lands of the input / output pads of the FPC are formed in a zigzag manner or by forming the via holes at the edges of the input / output pads, it is possible to prevent soldering defects It is possible to reduce the interval between the input / output pads of the FPC and to prevent the occurrence of defective open circuit of the FPC.

This makes it possible to prevent a driving operation failure of the liquid crystal panel or damage of the circuit part.

Further, by improving the connecting force between the pad and the first and second signal pads, there is an effect that the FPC, the control printed circuit board, and the data printed circuit board are stably fixed to each other.

1 is a perspective view schematically showing a liquid crystal panel of a liquid crystal display device of the present invention.
2 is a plan view schematically illustrating a connection of an FPC according to an embodiment of the present invention.
3 is a cross-sectional view taken along the line III-III in Fig.
4 is a plan view schematically showing a shape of an input / output pad portion of an FPC according to the first embodiment of the present invention.
5A to 5B are enlarged views of a part of FIG. 4;
6 is a plan view schematically showing the appearance of the input / output pad portion of the FPC according to the second embodiment of the present invention.
7A to 7B are enlarged views of a part of Fig. 6; Fig.

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

1 is a perspective view schematically showing a liquid crystal panel of a liquid crystal display according to an embodiment of the present invention.

As shown in the drawing, the liquid crystal panel 110 is a part that plays a key role in image display of the liquid crystal display device, and includes a first substrate 112 and a second substrate 114, And a liquid crystal layer (not shown).

Although not shown in the drawing, a plurality of gate lines and data lines intersect each other on the inner surface of a first substrate 112 called a lower substrate or an array substrate, pixels are defined, and thin- and a thin film transistor (TFT), which are connected in a one-to-one correspondence with the transparent pixel electrodes formed in the respective pixels.

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 the gate lines, the data lines, and the thin film transistors.

In addition, color filters of red (R), green (G), and blue (B) colors and transparent common electrodes covering the black matrix are 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.

The gate and data printed circuit boards 115 and 117 are connected to each other along at least one edge of the liquid crystal panel 110 via a connection member 116 such as a tape carrier package (TCP).

A control printed circuit board 119 for outputting a control signal is connected to the data printed circuit board 117. A timing control unit (not shown) and a power supply unit (not shown) are mounted on the control printed circuit board 119 And generates data / gate control signals and power supply signals using various electrical signals from the outside.

The control printed circuit board 119 and the data printed circuit board 117 are electrically connected through the FPC 200 and the data printed circuit board 117 is electrically connected to the gate printed circuit board 115.

At this time, the control printed circuit board 119 may be separately connected to the data printed circuit board 117 and the gate printed circuit board 115 through the respective FPCs 200.

On the other hand, the gate and data printed circuit boards 115 and 117 may be composed of an integrated printed circuit board having a data portion and a gate portion formed on one substrate.

Some of the control signals generated from the control printed circuit board 119 are applied to the data printed circuit board 117 and the rest are applied to the gate printed circuit board 115 via the data printed circuit board 117. [

Here, the applied various signals are converted into a video signal and a gate control signal, and a video signal to be displayed on the liquid crystal panel 110 is transmitted to a data line (not shown), and a signal for controlling the gate line To a gate line (not shown).

Accordingly, 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 transmits the signal voltage of the data driving circuit to the corresponding pixel electrode through the data line, The alignment direction of the liquid crystal molecules in the liquid crystal layer is changed by the electric field between the pixel electrode and the common electrode, resulting in a difference in transmittance.

A backlight unit (not shown) for supplying light to the back surface of the liquid crystal panel 110 is provided so that the difference in transmittance of the liquid crystal panel 110 is externally expressed.

Hereinafter, the FPC 200 for electrically connecting the control printed circuit board 119 and the data printed circuit board 117 will be described in detail with reference to FIG.

FIG. 2 is a plan view schematically showing the connection of the FPC according to the embodiment of the present invention, and FIG. 3 is a sectional view taken along the line III-III in FIG.

As shown in the figure, the FPC 200 includes a flexible base film 211, a plurality of metal wires 213 formed by patterning a conductive material on the base film 211, Output pad portions 217a and 217b.

A coverlay 215 is coated on the base film 211 to insulate the metal wires 213.

The input / output pads 217a and 217b are formed of a plurality of pads 219a and 219b provided at one end of each metal wiring 213. The pads 219a and 219b are connected to a control printed circuit board 119 and the data printed circuit board 117 by soldering.

At this time, via holes 220 are formed in the pads 219a and 219b for connection with the control printed circuit board 119 and the data printed circuit board 117, respectively.

That is, the pads 219a and 219b of the input / output pad portions 217a and 217b of the FPC 200 are connected to the input pad portion 217a formed at one end of the FPC 200 connected to the control printed circuit board 119 And an output pad portion 217a formed at the other end connected to the data printed circuit board 117. [ The input pad unit 217a includes a plurality of input pads 219a and the output pad unit 217b includes a plurality of output pads 219b.

The input pad 219a of the input pad portion 217a and the first signal pad 119a formed on the control printed circuit board 119 are electrically connected to each other through solder 220 applied to the inside of the via hole 220 passing through the input pad 219a And the output pad 219b of the output pad portion 217b is electrically connected to the second signal pad 117a and the output pad 219b formed on the data printed circuit board 117 The via holes 220 are electrically connected to each other by the solder 230 applied to the inside of the via holes 220.

Therefore, the control printed circuit board 119 and the data printed circuit board 117 are electrically connected to each other through the FPC 200. [

The via hole 220 serves not only to fix the FPC 200 to the control printed circuit board 119 and the data printed circuit board 117 but also to fix the FPC 200 to the control printed circuit board 119 and the data printed circuit board 117 The first and second signal pads 119a and 117a are filled with the solder 230 electrically connecting the input / output pads 219a and 219b of the FPC 200, respectively.

The width of the input / output pads 219a and 219b may be set to have a width corresponding to the width of the input / output pads 219a and 219b, When the width of the input / output pads 219a and 219b is reduced, the width of the via hole 220 must also be reduced to prevent the signal supply unit from being opened.

However, if the size of the via hole 220 is reduced, the solder 230 is not properly raised between the via holes 220, resulting in defective soldering due to cold or poor solderability.

Accordingly, the input / output pads 219a and 219b of the FPC 200 according to the embodiment of the present invention may further include a land 240 (see FIG. 4) in the periphery of the via hole 220, Output pads 219a and 219b of the FPC 200 and the control printed circuit board 119 and the data printed circuit board 117 are formed at the edges of the input / output pads 219a and 219b. It is possible to prevent the occurrence of defective soldering such as cold storage or non-storage of the second signal pads 119a and 117a.

Hereinafter, the present invention will be described in more detail with reference to the following embodiments.

- First Embodiment -

FIG. 4 is a plan view schematically illustrating the shape of the input / output pad portion of the FPC according to the first embodiment of the present invention. FIG. 5B is an enlarged view of a portion of FIG. Fig.

A via hole 220 is formed in an input / output pad 219a (not shown) of an input / output pad portion 217a (not shown) formed at one end of the FPC 200 .

The via hole 220 electrically connects the first and second signal pads 119a and 117a of the data printed circuit board 117 and the control printed circuit board 119 . 3) is supplied to the via hole 220 in the soldering process between the pad 219a and the first and second signal pads (119a and 117a in FIG. 3) so that the via hole 220 is electrically connected to the solder 3). Thus, the pads 219a and the first and second signal pads (119a and 117a in FIG. 3) are electrically connected to each other.

At this time, the ends of the pads 219a are each formed in the shape of a groove 250 recessed from the end of the pad 219a. The groove 250 is formed in a position where the solder (230 in FIG. 3) . 3) of the FPC 200 and the control printed circuit board 119 (FIG. 3) and the data printed circuit board (117 of FIG. 3) are soldered to adjacent pads 219a As shown in FIG.

In order to provide a high resolution liquid crystal display device, in order to prevent the size of the via hole 220 formed on the pad 219a from being reduced in the process of reducing the width of the pad 219a, (240) is formed.

That is, the via hole 220 formed on the pad 219a should be reduced in size as the width of the pad 219a is reduced to prevent the pad 219a from being opened. However, the via hole 220 The size of the solder (230 in FIG. 3) does not rise properly, resulting in defective soldering due to cold or poor soldering.

Therefore, by forming the land 240 having a larger width of the pad 219a in the vicinity of the via hole 220, the opening of the pad 219a does not occur even if the width of the pad 219a is reduced So that the size of the via hole 220 can be maintained.

It is preferable that the diameter of the via hole 220 is 50 to 300 占 퐉 and the width d1 of the land 240 formed around the via hole 220 is 50 to 150 占 퐉.

Particularly, the FPC 200 according to the first embodiment of the present invention is characterized in that the via holes 220 formed with the lands 240 are arranged on the pads 219a so as to be shifted from each other.

That is, when the via hole 220 formed on the first pad 219a-1 is located on the lower side defined by the drawing of the first pad 219a-1, the via hole 220 adjacent to the first pad 219a- The via hole 220 of the second pad 219a-2 to be positioned is located on the upper side defined in the drawing.

The via hole 220 of the third pad 219a-3 adjacent to and adjacent to the second pad 219a-2 is located on the upper side defined in the drawing.

When the via holes 220 are arranged so as to be shifted from each other, the interval between the pads 219a can be further reduced, and shorting of the pads 219a due to the lands 240 can be prevented.

That is, the pads 219a must be arranged so as to maintain a constant interval D1 in order to prevent electrical interference with each other. Therefore, as shown in FIG. 5A, the land 240 on each pad 219a The spacing between the lands 240 is formed to have a first spacing D1 and the lands 240 are spaced apart from each other by the lands 240. In the case where the via holes 220 are formed in the same line along the arrangement direction of the pads 219a, 219a are formed to have a second interval D2.

5B, when the via holes 220 including the lands 240 are arranged to be shifted from each other, the minimum spacing between the pads 219a is smaller than the first spacing D1 ) Can be formed.

3) of the FPC 200 as the solder (230 in FIG. 3) is widened in the soldering process by arranging the via holes 220 so as to be shifted from each other, And the soldering portion of the control printed circuit board (119 in FIG. 3) and the data printed circuit board (117 in FIG. 3).

When the via holes 220 are formed in the same line along the arrangement direction of the pads 219a, the pads 219a are bent by external pressure (or impact), and the bending of the pads 219a Stress along the via holes 220 located on the same line can cause damage to the pads 219a.

As a result, a disconnection failure occurs, a driving operation failure of the liquid crystal panel (110 in FIG. 1) occurs, or the circuit portion is damaged.

On the other hand, by arranging the via holes 220 so as to be shifted from each other as in the first embodiment of the present invention, it is possible to prevent the stress from being concentrated by the external pressure and to prevent the breakage of the pad 219a can do.

Therefore, it is possible to prevent the occurrence of disconnection failure, and it is possible to prevent the driving operation failure of the liquid crystal panel (110 in Fig. 1) or the damage of the circuit portion (not shown) from occurring.

At this time, the distance s between the via holes 220 formed in the adjacent pads 219a is preferably 300 to 1000 mu m.

- Second Embodiment -

FIG. 6 is a plan view schematically showing the shape of the input / output pad portion of the FPC according to the second embodiment of the present invention. FIG. 7B is an enlarged view of a portion of FIG. Fig.

A via hole 260 is formed in an input / output pad 219a (not shown) of an input or output pad portion 217a and 217b of FIG. 3 formed at one end of the FPC 200, .

The via hole 260 electrically connects the first and second signal pads (119a and 117a in Fig. 3) of the pad 219a, the control printed circuit board 119 (Fig. 3) and the data printed circuit board . That is, the solder 230 is supplied to the via hole 260 during the soldering process between the pad 219a and the first and second signal pads (119a and 117a in FIG. 3), and the via hole 260 is soldered by the solder 230 The pad 219a and the first and second signal pads (119a and 117a in FIG. 3) are electrically connected to each other.

The FPC 200 according to the second embodiment of the present invention is characterized in that the via hole 260 is formed along the edge of the pad 219a in the form of a groove recessed from the edge of the pad 219a toward the center thereof do.

Thus, connection characteristics between the FPC 200 and the control printed circuit board (119 in FIG. 3) and the data printed circuit board (117 in FIG. 3) can be improved.

That is, the via hole 260 is formed along the longitudinal edge of the pad 219a in the shape of a groove so that the solder 230 filled with the via hole 260 is electrically connected to the pad 219a from the edge of the pad 219a It spreads to the center.

Thus, the solder 230 is spread over a large area of the pad 219a so that the pad 219a and the control printed circuit board (119 in FIG. 3) and the data printed circuit board (117 in FIG. 3) The contact area between the first and second signal pads (119a and 117a in Fig. 3) is increased, and the connection force is increased to increase the contact force between the FPC 200 and the control printed circuit board (119 in Fig. 3) 117) are stably fixed to each other.

7A to 7B, the solder 230 filled with the via hole 260 of the pad 219a is electrically connected to the pad 219a of the FPC 220 and the control printed circuit board 3) of the data printed circuit board (117 of FIG. 3) and the pad 219a of the FPC 200 and the control printed circuit board (119 in FIG. 3) and the first and second signal pads (119a and 117a in FIG. 3) of the data printed circuit board (117 in FIG. 3) are electrically connected to each other.

7A, when the via hole 260 is located at the center of the pad 219a, the solder 230 filled in the via hole 260 is located only at the center of the pad 219a, As shown in Fig.

7B, the via hole 260 is formed in the shape of a groove formed along the longitudinal edge of the pad 219a, so that the solder 230 filled with the via hole 260 is electrically connected to the pad 219a And has an area of B and C.

7A and 7B, when the via hole 260 is formed along the longitudinal edge of the pad 219a, the spread area of the solder 230 filled with the via hole 260 becomes wider .

Particularly, the regions B and C are formed to be approximately twice as large as the region A.

3) of the control printed circuit board (119 in FIG. 3) and the data printed circuit board (117 in FIG. 3) when the area of the solder 230 filled with the via hole 260 is widened The contact area between the pad 219a and the first and second signal pads 119a and 117a of FIG. 3 is improved by increasing the contact area between the first signal pad 121a and the second signal pad 119a and 117a of FIG. 3 .

By improving the connection force between the pad 219a and the first and second signal pads 119a and 117a in FIG. 3, the FPC 200 and the control printed circuit board (119 in FIG. 3) and the data printed circuit board (117 in Fig. 3) are stably fixed to each other.

Accordingly, it is possible to prevent the occurrence of disconnection of the FPC 200, and it is possible to prevent the driving operation failure of the liquid crystal panel (100 of FIG. 1) or the damage of the circuit portion (not shown) .

At this time, it is preferable that at least two or more of the via holes 260 are provided on one longitudinal edge of the pad 219a, and the height h drawn from the edge is equal to 1/2 of the width d2 of the pad 219a. 3 < / RTI >

The via holes 260 may be formed at one end of the pads 219a perpendicular to the longitudinal direction of the pads 219a and the via holes 260 formed at the opposite edges of the pads 219a may be connected to each other It may be formed at a corresponding position or may be formed to be shifted from each other.

As described above, the present invention is applicable to a case where a via hole (220 in FIG. 5B) in which a land (240 in FIG. 5B) of the input / output pad 219a (not shown) of the FPC 200 is formed, Output pad 219a (not shown), it is possible to prevent the occurrence of soldering defects such as cold soldering or insufficient soldering, and at the same time, it is possible to prevent the occurrence of defective soldering between the input / output pads 219a It is possible to reduce the interval D1 and to prevent the disconnection failure of the FPC 200 from occurring.

This makes it possible to prevent a driving operation failure of the liquid crystal panel (110 in FIG. 1) or damage to the circuit portion (not shown).

3) by improving the connecting force between the input / output pads 219a (not shown) and the first and second signal pads (119a and 117a in Fig. 3) And the data printed circuit board (1197 in Fig. 3) are stably fixed to each other.

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.

200: FPC, 217a: input pad portion,
219a: input pads 219a-1, 219a-2, 219a-3 (first to third input pads)
220: via hole, 240: land, 250: groove

Claims (9)

A base film,
An input pad and an output pad located above the base film and connected to the signal pad of the printed circuit board;
A cover ray positioned above the input pad and the output pad;
A plurality of input and output pads formed on the input and output pads, respectively,
Wherein a groove is provided at an end of each of the input pad and the output pad,
Wherein the groove is located corresponding to an end of the base film,
Wherein the cover rails expose the input pads and the output pads in correspondence to the via holes, and the solder filled in the via holes is flush with the cover rails.
The method according to claim 1,
And the via holes are arranged in a zigzag form.
delete The method according to claim 1,
And a land is formed around the via hole, the land being formed to be wider than the width of the input pad and the output pad.
The method according to claim 1,
And a distance between the via-holes is 300 to 1000 占 퐉.
A base film,
An input pad and an output pad located above the base film and connected to the signal pad of the printed circuit board;
A cover ray positioned above the input pad and the output pad; The input pad and the output pad are electrically connected to each other through a via hole
/ RTI >
A groove is provided at an end of each of the input pad and the output pad,
Wherein the groove is located corresponding to an end of the base film,
Wherein the cover rails expose the input pads and the output pads in correspondence to the via holes, and the solder filled in the via holes is flush with the cover rails.
The method according to claim 6,
Wherein the via hole is formed at two opposing edges of the input pad and the output pad, and at least two of the via holes are formed on one edge of the flexible printed circuit board.
8. The method of claim 7,
Wherein the via holes formed at the opposite edges of the input pad and the output pad are formed to be offset from each other.
delete

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