JP2003186044A - Liquid crystal display device and flexible board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which can supply an input signal to a liquid crystal driving IC without using a wiring board other than a flexible board on which the liquid crystal driving IC is mounted by using internal wires formed on a glass substrate. <P>SOLUTION: A plurality of flexible boards 20 on each of which a liquid crystal driving IC 1A generating a liquid crystal driving signal based on an input signal is mounted, are connected to the circumference of a TFT glass substrate 8. Each of flexible boards 20 has signal output terminals 17 and 22 which output the input signal to the glass substrate 8. The glass substrate 8 has internal wires 13-2 and 24 which supply the input signal supplied through the signal output terminals to one of the plurality of flexible boards 20 as it is. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device for supplying a display signal to a liquid crystal display section formed on a glass substrate by using a flexible substrate.

In recent years, there has been a strong demand for lowering the cost of liquid crystal display devices, and reducing the manufacturing cost and material cost of liquid crystal display devices has become a major issue. In order to meet such a demand for cost reduction, a method of reducing the number of components as much as possible has been proposed, such as providing a wiring region on a TFT glass substrate to eliminate the printed circuit board.

[0003]

2. Description of the Related Art A liquid crystal display device formed on a TFT glass substrate generally includes a liquid crystal driving IC mounted on a flexible substrate such as a chip on film (COF) substrate.
Drive signal is supplied from. The flexible substrate on which the liquid crystal driving IC is mounted is connected around the TFT glass substrate. Further, in order to supply a signal to the liquid crystal driving IC mounted on the flexible substrate, the flexible substrate on which the signal input circuit pattern is formed is different from the flexible substrate on which the liquid crystal driving IC is mounted or the TFT glass substrate. Connected.

FIG. 1 is a diagram showing a structure in which a flexible printed circuit board for supplying an input signal is connected to a flexible circuit board on which a liquid crystal driving IC is mounted. In FIG. 1, a COF substrate 2 which is a flexible substrate on which a liquid crystal driving IC 1 is mounted is connected to a TFT glass substrate 8 provided with a common glass substrate 7 on which a liquid crystal display section is formed.

The liquid crystal driving IC 1 is mounted on the COF substrate 2 at substantially the center thereof. The circuit pattern (output signal wiring) 3 connected to the output terminal of the liquid crystal driving IC 1 extends to one side of the COF substrate 2, and the tip portion functions as the COF output side terminal 4. On the other hand, the circuit pattern (input signal wiring) 5 connected to the input terminal of the liquid crystal driving IC 1 extends in the direction opposite to the output signal wiring 3 and is gathered on a piece on the opposite side of the COF substrate 2 to form a tip portion. Functions as the COF input side terminal 6.

The output signal wiring 3 and the input signal wiring 5 formed on the COF substrate 2 are the COF output side terminal 4 and the COF output terminal 5.
Insulation is performed by coating with a resist except for the portion where the input-side terminal 6 is provided (hatched portion in the figure).

The COF substrate 2 is connected to a TFT glass substrate 8 provided around a common glass substrate 7 on which a liquid crystal display section is formed, and each of the COF output terminals 4 has a T-type.
It is connected to the corresponding glass substrate input terminal 9 formed on the FT glass substrate 8. As a result, the output signal of the driving IC 1 is supplied to the liquid crystal display component via the signal output wiring 3, the COF output side terminal 4 and the glass substrate input terminal 9.

On the other hand, a printed wiring board 10 for input wiring is connected to the COF input terminal 6 side of the COF board 2. The input wiring printed circuit board 10 is commonly connected to the plurality of COF boards 2. Input wirings 11 for supplying input signals to the plurality of COF boards 2 are formed on the input wiring printed circuit board 10.

An FPC cable 1 for supplying an input signal from an external control circuit is provided at one end 11a of the input wiring 11.
2 are connected. The input wiring 11 extends along the plurality of COF boards 2 to which the input wiring printed board 10 is connected, and the input wiring input terminals 11b are formed at positions corresponding to the respective COF input terminals 6 of the COF board 2. It With the printed wiring board 10 for input wiring connected to the COF board,
The input wiring input terminal 11b is the COF of each COF substrate 2.
It is connected to the input terminal 6. As a result, the input signal input to the one end 11a of the input wiring 11 is sequentially supplied to the COF substrate 2 via the input wiring 11 and the input wiring input terminal 11b.

With the above configuration, the input signal supplied from the external control circuit is input wiring printed circuit board 1
It is input to the COF substrate 2 via 0, converted into a liquid crystal drive signal by the driving IC 1, and supplied to the TFT glass substrate 8.

A method of supplying an input signal to the COF board 2 without using the input wiring printed board 10 has also been proposed. FIG. 2 is a diagram for explaining a configuration in which input wirings are formed on a TFT glass substrate and an input signal is supplied to the COF substrate without using a printed wiring board for input wirings.

In the configuration shown in FIG. 2, the FPC cable 12 for supplying an input signal from an external control circuit is TF.
It is connected to the T glass substrate 8. Internal wiring 13-1 is formed as an input signal wiring on the TFT glass substrate 8, and the COF substrate 2A is formed through the internal wiring 13-1.
An input signal is supplied to.

Here, the liquid crystal driving IC 1A used in the configuration shown in FIG. 2 is an IC provided with a terminal for outputting an input signal as it is. The input signal wiring 14 of the liquid crystal driving IC 1A makes a U-turn on the COF substrate 2A.
The F input terminal 15 is provided on the same side as the COF output terminal 4. Further, the COF substrate 2A is provided with a re-input signal wiring 16 connected to a terminal that outputs an input signal as it is. The re-input signal wiring 16 makes a U-turn on the COF substrate 2A, and the COF re-input terminal 17 is provided on the same side as the COF output terminal 4. That is, on one side of the COF substrate 2A, the COF output terminal 4 is sandwiched and the COF input terminal 15 and the COF re-input terminal 17 are aligned left and right.

On the other hand, on the TFT glass substrate 8, in addition to the internal wiring 13-1, the COF re-input terminal 1 of the COF substrate 2A.
Internal wiring (inter-COF wiring) 13-2 for connecting 7 to the COF input terminal 15 of the adjacent COF substrate 2A is also formed.

With the above configuration, the input signal input from the FPC cable 12 is supplied to the COF substrate 2A through the internal wiring 13-1 of the TFT glass substrate 8 and the liquid crystal drive signal generated by the liquid crystal drive IC 1A. Is supplied to the glass substrate input terminal 9 of the TFT glass substrate 8. At the same time, the input signal supplied to the liquid crystal driving IC 1A is output from the terminal that outputs the input signal as it is, and is supplied to the COF re-input terminal 17 via the re-input signal wiring 16.
It is supplied to the COF input terminal 15 of the adjacent COF substrate 2A via the inter-COF wiring 13-2 of the FT glass substrate 8. Therefore, the input signal supplied from the FPC cable 12 is the internal wiring 13- provided on the glass substrate 8.
1 and 13-2 and the input signal wiring 14 and the re-input signal wiring 16 provided on each COF substrate 2A make adjacent C
It is sequentially supplied to the OF substrate 2A.

[0016]

In the configuration shown in FIG. 1 described above, it is necessary to provide the input wiring printed circuit board 10 for connecting a plurality of COF substrates 2, and the input wiring printed circuit board 10 is used in the manufacturing process of the liquid crystal display device. The process of connecting the board | substrate 10 was required. For this reason, the number of manufacturing steps of the liquid crystal display device increases, and the component cost of the input wiring printed circuit board 10 is included in the manufacturing cost of the liquid crystal display device.

On the other hand, in the structure shown in FIG. 2, the printed wiring board 10 for input wiring is not used, but a step of connecting the FPC cable 12 to the TFT glass substrate 8 is required, and the number of manufacturing steps of the liquid crystal display device increases. Was there.

The present invention has been made in view of the above points, and by utilizing the internal wiring formed on the glass substrate, it is possible to use a wiring substrate other than the flexible substrate on which the liquid crystal driving IC is mounted, An object of the present invention is to provide a liquid crystal display device capable of supplying an input signal to a liquid crystal driving IC.

[0019]

In order to solve the above problems, the present invention is characterized by taking the following means.

According to a first aspect of the present invention, a glass substrate on which a liquid crystal display portion is formed, and a glass substrate connected to the periphery of the glass substrate,
A liquid crystal display device comprising: a plurality of flexible substrates on which a liquid crystal driving IC that generates a liquid crystal driving signal based on an input signal is mounted; wherein the glass substrate is an input supplied from the first flexible substrate. A first internal wiring for supplying a signal to the second flexible board; and a second internal wiring for supplying an input signal supplied from the first flexible board to the first flexible board as it is. And internal wiring of.

According to the first aspect of the invention, the input signal can be sequentially supplied to the plurality of flexible substrates through the internal wiring formed on the glass substrate, and it is necessary to separately provide a substrate for signal input. Disappears. Therefore, an input signal can be supplied to the liquid crystal driving IC without using a wiring substrate other than the flexible substrate on which the liquid crystal driving IC is mounted, and the manufacturing process and manufacturing cost of the liquid crystal display device can be reduced. .

According to a second aspect of the present invention, in the liquid crystal display device according to the first aspect, one of the plurality of flexible substrates directly supplies an input signal supplied from an external circuit to the glass substrate. It is characterized in that it has through wiring.

According to the second aspect of the present invention, after the input signal supplied from the external circuit is once supplied to the glass substrate via the flexible substrate, the input signal can be supplied from the glass substrate side to the flexible substrate. it can. Therefore, it is not necessary to provide a circuit board to supply the input signal to the glass substrate.

According to a third aspect of the present invention, in the liquid crystal display device according to the first aspect, each of the plurality of flexible substrates directly supplies the input signal supplied from the glass substrate to the glass substrate. It has a through wiring for

According to a fourth aspect of the present invention, there is provided a flexible substrate which is connected to the periphery of a glass substrate on which a liquid crystal display section is formed and which has a liquid crystal driving IC for generating a liquid crystal driving signal based on an input signal. It has a through wiring for supplying an input signal supplied from an external circuit to the glass substrate as it is.

According to the third and fourth aspects of the present invention, the through signal of the flexible substrate and the internal wiring of the glass substrate can guide an input signal to the flexible substrate at an arbitrary position, and the input signal can be mounted on the flexible substrate. The input signal can be supplied starting from the liquid crystal driving IC thus prepared. Therefore, the degree of freedom in designing the input signal supply path is improved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is a diagram for explaining an input signal supply path in the liquid crystal display device according to the first embodiment of the present invention. 3, parts that are the same as the parts shown in FIG. 2 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

In this embodiment, an input signal is supplied to the liquid crystal display device without using the input wiring printed circuit board 10 shown in FIG. The liquid crystal display device according to the present embodiment has a configuration in which a plurality of flexible substrates 20 are connected to the TFT glass substrate 8. The flexible substrate 20 is, for example, COF
Although it is composed of a substrate, a TAB substrate and the like, a COF substrate is used in the present embodiment. Below, flexible substrate 2
0 is called a COF substrate 20. A liquid crystal driving IC 1A having a terminal for directly outputting an input signal is mounted on each of the COF substrates 20.

The COF substrate 20 is basically the C shown in FIG.
It has the same configuration as the OF substrate 2A, except that a COF through wiring 21 is added. COF through wiring 21
Is extended between the side on which the COF output terminal is provided and the side on the opposite side of the COF substrate 20, and the side opposite to the through wiring output terminal 22 provided on the side on which the COF output terminal is provided. It extends to the through wiring input terminal 23 provided on the side.

TF corresponding to the through wiring output terminal 22
The signal return wiring 24 is formed on the T glass substrate 8. With the COF substrate 20 connected to the TFT glass substrate 8, one end of the signal feedback wiring 24 is connected to the through wiring output terminal 22. The signal return wiring 24 is folded back in a U shape on the TFT glass substrate 8, and the signal return wiring 24
The other end of is connected to the COF input signal terminal 15 of the COF substrate 20.

Through wiring input terminal 23 of COF board 20
Is connected to the control circuit board 28 on which the control circuit 29 is mounted, and the input signal from the control circuit 29 is supplied to the through wiring input terminal 23 of the COF board 20.

Next, the input signal supply path in the liquid crystal display device according to the present embodiment will be described with reference to FIGS. 4 and 5. 4 is a diagram showing the configuration shown in FIG. 3 in a wider range, and FIG. 5 is a diagram showing the supply path of the input signal with an arrow in the configuration shown in FIG.

In the configuration according to this embodiment, the COF
The input signal supplied to the through wiring input terminal 23 of the substrate 20 is supplied to the signal feedback wiring 24 of the TFT glass substrate 8 via the through wiring 21 and the through wiring output terminal 22 of the COF substrate 20, and is folded back to COF. C of substrate 20
It is supplied to the OF input terminal 15.

The input signal supplied to the COF input terminal 15 is supplied to the liquid crystal driving IC 1A via the input signal wiring 14, and the liquid crystal driving IC 1A generates a liquid crystal driving signal based on the supplied input signal. . The generated liquid crystal drive signal is supplied to the glass substrate input terminal 9 of the TFT glass substrate 8 via the output signal wiring 3 and the COF output terminal 4. At the same time, the input signal supplied to the liquid crystal driving IC 1A is output from the terminal that outputs the input signal as it is,
It is supplied to the COF re-input terminal 17 via the re-input signal wiring 16 and is supplied to the COF input terminal 15 of the adjacent COF substrate 20 via the inter-COF wiring 13-2 of the TFT glass substrate 8.

Therefore, the input signal supplied from the control circuit board 28 is re-input to the internal wirings 13-1 and 13-2 provided on the TFT glass substrate 8 and the input signal wiring 14 provided on each COF substrate 20. With the signal wiring 16,
It is sequentially supplied to the adjacent COF substrates 20.

As described above, in this embodiment, the through wiring 21 formed on the COF substrate 20 and the signal feedback wiring 24 formed on the TFT glass substrate 8 are used without using the FPC cable for the input signal. Input signal to CO
It can be supplied to the F input terminal 15. Therefore,
Input wiring printed circuit board 10 and FP as shown in FIG.
Since the input signal from the control circuit 29 can be supplied to the liquid crystal display device without using the C cable 12, the number of manufacturing steps of the liquid crystal display device can be reduced and the component cost can be reduced.

Next, a second embodiment of the present invention will be described. FIG. 6 is a diagram for explaining an input signal supply path in the liquid crystal display device according to the second embodiment of the present invention. FIG. 7 is an enlarged view of a part of FIG. Figure 6
7 and 7, parts that are the same as the parts shown in FIG. 3 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

The liquid crystal display device according to the present embodiment uses the signal input path in the above-described first embodiment as the source side input signal path and the gate side input signal path is different.

In the present embodiment, the input signal supplied to the gate side is also transferred to the T side via the COF substrate 20 on the source side.
It is supplied to the FT glass substrate 8. The gate side input signal is
It is supplied to the COF substrate 30 on the gate side via the gate-source wiring 26 formed on the TFT glass substrate 8.

A plurality of COF substrates 30 on the gate side are connected to the TFT glass substrate 8 in a state where a plurality of COF substrates 30 are aligned. Here, the input signal on the source side is sequentially supplied from the left side to the right side in FIG. 6 according to the display method of a general liquid crystal display device. The input signals on the gate side are generally input in order from top to bottom. In the case of the configuration shown in FIG. 6, since the gate side input signal is supplied from the lower side of the liquid crystal display device, the gate side input signal is first guided to the uppermost COF substrate 30 in FIG. There must be.

Therefore, in this embodiment, the COF substrate 3 is used.
By providing the COF through wiring 31 on each of the 0 and the inter-COF wiring 34 on the TFT glass substrate 8, the input signal on the gate side is first transmitted to the uppermost COF substrate 30.
Supply up to. A through wiring input terminal 32 is provided at one end of the through wiring 31. The through wiring 31 extends from the through wiring input terminal 32 along the outer circumference of the COF substrate and is connected to the through wiring output terminal 33 provided on the opposite side of the side where the through wiring input terminal 32 is provided.

The input signal on the gate side supplied from the uppermost COF 30 to the TFT glass substrate 8 is returned to the uppermost COF substrate 30 again by the signal feedback wiring 35, similarly to the input signal on the source side. It is sequentially supplied to the lower COF substrate 30 via the through wiring 36 of the TFT glass substrate 8. FIG. 8 is a diagram showing by arrows the signal paths of the input signals on the gate side as described above.

As described above, according to the present embodiment, like the first embodiment, the through wiring 21 formed on the COF substrate 20 is used without using the FPC cable for the input signal. Also, an input signal is sent to the COF input terminal 1 via the signal feedback wiring 24 formed on the TFT glass substrate 30.
5 can be supplied. Therefore, the printed wiring board 10 for input wiring and the FPC cable 1 as shown in FIG.
Since the input signal from the control circuit can be supplied to the liquid crystal display device without using 2, the number of manufacturing steps of the liquid crystal display device can be reduced and the component cost can be reduced. In addition, the input signal on the source side and the input signal on the gate side can be supplied through only one COF substrate, and the number of manufacturing steps of the liquid crystal display device can be reduced and the component cost can be reduced. . Further, for example, even if the input signal on the source side is supplied from the lower side of the screen, it can be guided to the upper side of the screen by the through wiring of the COF substrate and the inter-COF wiring of the TFT glass substrate. The degree of freedom can be increased.

In the first embodiment described above, the input signal on the gate side is first guided from the lower side to the upper side of the screen, but the signal path of the input signal on the source side has the same configuration. You can also do it.

In the first and second embodiments described above, the COF substrate is used as the flexible substrate on which the liquid crystal driving IC is mounted. However, the TAF is used instead of the COF substrate.
A B substrate may be used.

As described above, according to the present invention, various effects described below can be realized. According to the first aspect of the invention, the input signal can be sequentially supplied to the plurality of flexible substrates through the internal wiring formed on the glass substrate, and it is not necessary to separately provide a signal input substrate. Therefore, the liquid crystal driving IC can be used without using a wiring substrate other than the flexible substrate on which the liquid crystal driving IC is mounted.
An input signal can be supplied to C, and the manufacturing process and manufacturing cost of the liquid crystal display device can be reduced.

According to the second aspect of the invention, after the input signal supplied from the external circuit is once supplied to the glass substrate via the flexible substrate, the input signal can be supplied from the glass substrate side to the flexible substrate. it can. Therefore, it is not necessary to provide a circuit board to supply the input signal to the glass substrate.

According to the third and fourth aspects of the present invention, the through wiring of the flexible substrate and the internal wiring of the glass substrate can guide the input signal to the flexible substrate at an arbitrary position, and can be mounted on the flexible substrate. The input signal can be supplied starting from the liquid crystal driving IC thus prepared. Therefore, the degree of freedom in designing the input signal supply path is improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration in which a flexible printed circuit board for supplying an input signal is connected to a flexible circuit board on which a liquid crystal driving IC is mounted.

FIG. 2 is a diagram for explaining a configuration in which input wirings are formed on a TFT glass substrate and an input signal is supplied to a COF substrate without using a printed wiring board for input wirings.

FIG. 3 is a diagram for explaining an input signal supply path in the liquid crystal display device according to the first embodiment of the present invention.

FIG. 4 is a diagram showing the configuration shown in FIG. 3 in a wider range.

5 is a diagram showing input signal supply paths with arrows in the configuration shown in FIG.

FIG. 6 is a diagram for explaining an input signal supply path in the liquid crystal display device according to the second embodiment of the present invention.

FIG. 7 is a diagram showing a part of FIG. 6 in an enlarged manner.

FIG. 8 is a diagram showing an input signal supply path with arrows in the configuration shown in FIG.

[Explanation of symbols]

1A LCD driving IC 3 signal output terminals 4 COF output side terminal 7 Common glass substrate 8 TFT glass substrate 9 Glass substrate input terminal 13-1 Internal wiring 13-2, 34, 36 COF wiring 14 Input signal wiring 15 COF input terminal 15 16 Re-input signal wiring 16 17 COF re-input terminal 17 20,30 COF substrate 21,31 COF through wiring 22,32 Through wiring input terminal 23,33 Through wiring output terminal 24, 35 signal return wiring 28 Control circuit board 29 Control circuit

Continued front page    (72) Inventor Takashi Yuda             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited (72) Inventor Satoshi Sekido             4-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa             No. 1 within Fujitsu Limited F-term (reference) 2H092 GA29 GA32 GA50 GA51 JA24                       JB22 JB31 NA27 NA29 PA01                       PA06                 5C094 AA43 AA44 AA45 BA43 DB01                       DB02 DB05 EB10                 5E344 AA02 AA22 BB02 BB03 BB04                       BB12 EE11 EE21                 5G435 AA17 BB12 EE40 EE47

Claims (4)

[Claims] 1. A glass substrate on which a liquid crystal display unit is formed, and a plurality of flexible substrates connected to the periphery of the glass substrate and mounted with a liquid crystal driving IC for generating a liquid crystal driving signal based on an input signal. A liquid crystal display device comprising: the glass substrate; a first internal wiring for supplying an input signal supplied from the first flexible substrate to the second flexible substrate; A liquid crystal display device comprising: a second internal wiring for supplying an input signal supplied from a flexible substrate to the first flexible substrate as it is. 2. The liquid crystal display device according to claim 1, wherein one of the plurality of flexible substrates has a through wiring that directly supplies an input signal supplied from an external circuit to the glass substrate. Liquid crystal display device characterized by. 3. The liquid crystal display device according to claim 1, wherein each of the plurality of flexible substrates has a through wiring for supplying an input signal supplied from the glass substrate to the glass substrate as it is. A liquid crystal display device characterized by the above. 4. A flexible substrate, which is connected to the periphery of a glass substrate on which a liquid crystal display section is formed and has a liquid crystal driving IC for generating a liquid crystal driving signal based on an input signal, the flexible substrate being supplied from an external circuit. A flexible substrate having through wiring for supplying the input signal as it is to the glass substrate.