JPH1039775A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of the snapping of a wire in a drive circuit by specifying a formed position of a slit formed on the substrate surface of the drive circuit. SOLUTION: All of respective wiring layers 32A connected to a side of a printed circuit board are formed so as to stride across another slit 35 formed on the substrate 31 in a part between its terminal part 32T and the terminal part 32t of the side connected to a semiconductor chip 33. The drive circuit 3 formed in such a manner are connected to respective terminal groups of the liquid crystal panel by thermocompression through an anisotropic conductive film in respective terminal groups 32T of its liquid crystal display panel 1 side, and are connected to respective terminal groups of the printed circuit board through solder in respective terminal groups 32T of the printed circuit board side. By particularly forming the slit 35 on the substrate 31 of the drive circuit 3 in such a manner, the snapping of a wire doesn't occur in the wiring layers 32 provided crawledly on the surface of the substrate 31.

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 having a built-in video signal drive circuit.

[0002]

2. Description of the Related Art For example, a liquid crystal display panel incorporated in a liquid crystal display device called an active matrix type has a liquid crystal side surface of one of a pair of transparent substrates disposed mutually via the liquid crystal. , A gate signal line extending in the x direction and juxtaposed in the y direction, and a drain signal line insulated from each gate signal line and extending in the y direction and juxtaposed in the x direction are formed.

[0005] Each rectangular region surrounded by each of the gate signal lines and the drain signal lines forms a pixel region. In each pixel region, a scanning signal (voltage) to the gate signal line is supplied. A thin film transistor that is turned on by the supply and a pixel electrode (transparent electrode) to which a video signal (voltage) supplied to the drain signal line via the turned on thin film transistor is applied.

In such a liquid crystal display panel, a scanning signal is sequentially supplied to each gate signal line, and a video signal is sequentially supplied to each drain signal line in accordance with the timing. To the common electrode (transparent electrode) formed on the liquid crystal side surface of another transparent substrate that is disposed oppositely, and an electric field is generated between these electrodes. The light transmittance of the liquid crystal is controlled.

For this reason, in the liquid crystal display device, a scanning drive circuit for supplying a scanning signal to the gate signal line and a video signal for supplying a video signal to the drain signal line are provided around the liquid crystal display panel. Usually, a signal drive circuit is provided.

The scanning driving circuit and the video signal driving circuit (hereinafter, these may be referred to as a driving circuit as required) are formed by a circuit formed by a so-called tape carrier system, and are formed of a flexible film. A semiconductor chip is mounted on a substrate, and each electrode of the semiconductor chip is led out to a terminal group through each wiring layer formed by being laid on the substrate.

That is, the liquid crystal display device is configured such that a printed circuit board on which a power supply circuit and the like are mounted is arranged close to the periphery of the liquid crystal display panel, and a crotch is provided between the liquid crystal display panel and the printed circuit board. Are arranged in a state where the terminal groups are connected to the terminal group formed on the liquid crystal display panel side and the terminal group formed on the printed circuit board side by soldering or the like, respectively.

[0008]

However, in the liquid crystal display device having such a configuration, it has been confirmed that the signal transmission between the drive circuit and the printed circuit board is not partially performed when the liquid crystal display device is driven. It came to be.

As a result of pursuing this cause, the following has been found.

That is, the difference in the coefficient of thermal expansion of the drive circuit with respect to the liquid crystal display panel (small for the drive circuit) does not matter so much, but the difference in the coefficient of thermal expansion for the printed circuit board (large for the drive circuit) is small. This is not negligible, and so-called repetition of thermal cycling causes repeated occurrence of distortion especially in the portion of the drive circuit on the printed circuit board side.

For this reason, a disconnection occurs in the above-described portion of the wiring layer formed on the flexible substrate.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid crystal display device in which disconnection in a driving circuit is prevented.

[0013]

In order to achieve the above object, the present invention basically provides a liquid crystal display panel,
The liquid crystal display panel is composed of a printed circuit board arranged close to at least one side of the liquid crystal display panel, and a drive circuit arranged between the printed circuit board and the liquid crystal display panel. A semiconductor chip is mounted on a film-like flexible substrate, and each electrode of the semiconductor chip is connected to the liquid crystal display substrate side and the printed substrate side via each wiring layer formed by laying on the substrate. In a liquid crystal display device comprising a group of terminals, a slit is formed in a part of the substrate surface of the drive circuit, and the slit connects the electrode of the semiconductor chip and the terminal group connected to a printed circuit board side. Each of the wiring layers to be connected is formed at a position where the wiring is formed by extending the slit.

In the liquid crystal display device configured as described above, by providing the above-described slits in the driving circuit, distortions in directions different from each other are formed on the substrate surface at respective portions bordering the slits. Even if it occurs,
Since the wiring layer can be stretched by its own elasticity at a portion where the slit is crawled, disconnection of the wiring layer can be avoided.

Therefore, disconnection in the drive circuit can be prevented.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the liquid crystal display device according to the present invention will be described below with reference to the drawings.

FIG. 2 is an exploded perspective view showing one embodiment of the liquid crystal display device according to the present invention.

In FIG. 1, a liquid crystal display panel 1 is provided. A printed circuit board 2 on which a power supply circuit and the like are mounted is provided around the liquid crystal display panel 1 (the other three sides except one side in the figure). The printed circuit board 2
A drive circuit 3 is fixedly disposed between the liquid crystal display panel 1 and the liquid crystal display panel 1. The drive circuit 3 will be described later in detail.

The liquid crystal display panel 1 in which the printed board 2 and the drive circuit 3 are integrally provided is arranged on the intermediate frame 4. The intermediate frame 4 is formed of a frame provided with an opening 4A at least in a portion where the liquid crystal display panel 1 is arranged, and further, the opening 4A is provided between the intermediate frame 4 and the liquid crystal display panel 1. The light diffusion plate is arranged so as to block the light.

On the other hand, a shield case 6 is disposed above the liquid crystal display panel 1 (including the printed circuit board 2 and the drive circuit 3) disposed on the intermediate frame 4, and is provided with a claw 6A provided therearound. It can be swaged to the intermediate frame 4. The shield case 6 has a display window 6B for exposing the display section of the liquid crystal display panel 1 so that an observer can observe the liquid crystal display panel 1 through the display window 6B.

A cold cathode ray tube 7 is arranged on the back surface of the intermediate frame 4. The cold cathode ray tubes 4 are composed of, for example, a plurality (four in the figure), and are each supported by a support frame 7A so that the cold cathode ray tubes 4 are spaced apart from each other. Are located.

A supporting frame 7A for supporting the cold cathode ray tube 7
The lower case 8 is sandwiched between the intermediate frame 4 and the lower case 8. The light from the cold cathode ray tube 7 is diffused on a surface of the lower case 8 on the side of the cold cathode ray tube 7. 5
A light reflecting plate 8A for irradiating light uniformly on the side (therefore, the liquid crystal display panel 1 side) without waste is formed.

FIG. 3 is a view showing an equivalent circuit showing the power supply circuit and the like and the drive circuit 3 mounted on the liquid crystal display panel 1 and the printed circuit board 2 arranged around the liquid crystal display panel 1. As shown in FIG. The figure is a circuit diagram, but is drawn corresponding to an actual geometric arrangement.

In the drawing, first, on one liquid crystal side surface of the transparent substrates arranged to face each other via the liquid crystal of the liquid crystal display panel 1, they extend in the x direction in the drawing and are arranged in parallel in the y direction. A gate signal line GL and a drain signal line DL which is insulated from each of the gate signal lines GL, extends in the y direction and is arranged in parallel in the x direction, and these gate signal lines GL and drain signal lines DL are formed. Each of the rectangular regions surrounded by the circles constitutes a pixel region.

In each of these pixel regions, a thin film transistor TFT turned on by the supply of a scanning signal (voltage) to the gate signal line GL, and a drain signal line DL is supplied via the turned on thin film transistor TFT. And a pixel electrode ITO (transparent electrode) to which a video signal (voltage) is applied.

An additional capacitive element Cadd is formed between the pixel electrode ITO and a gate signal line GL for turning on the thin film transistor TFT and another gate signal line GL adjacent to the gate signal line GL. This additional capacitance element Cadd
Thereby, for example, when the thin film transistor TFT is turned off, an effect is obtained such that the video signal applied to the pixel electrode ITO is accumulated for a long time.

A common electrode (transparent electrode) common to each pixel region is formed on the other transparent substrate surface of the liquid crystal display panel 1 which faces through the liquid crystal. An electric field corresponding to a video signal is generated between the device and the ITO, and the light transmittance of the liquid crystal is controlled by the electric field.

A vertical scanning circuit 3A for supplying a scanning signal to the gate signal line GL and the drain signal line D are provided around the liquid crystal display panel 1 thus configured.
A video signal drive circuit 3B for supplying a video signal to L is provided, and a power supply circuit / CRT-TFT conversion circuit 2A for supplying power to the circuits 3A and 3B is provided.

Here, the power supply circuit / CRT-TFT conversion circuit 2A
Are mounted on the printed circuit board 2, and the vertical scanning circuit 3A and the video signal driving circuit 3B are each configured as a plurality of the driving circuits 3.

That is, as shown in FIG. 4, the drive circuit 3 in the vertical scanning circuit 3A is divided into a plurality (three in FIG. 4), and the drive circuit 3 in the video signal drive circuit 3B is also divided into a plurality ( In the figure, it is divided into 12 parts. As described above, the driving circuit 3 is divided so as to have the same configuration.
This is intended to facilitate manufacturing.

FIG. 1 is a block diagram showing one of the driving circuits 3, wherein FIG. 1A is a plan view, and FIG.
It is sectional drawing in a line.

In FIG. 1, there is a flexible substrate 31 in the form of a film, and an opening 31A is formed in a central portion excluding a peripheral portion thereof.

A plurality of wiring layers 32 called leads are formed on the front surface of the substrate 31 in FIG. Each of the wiring layers 32 is divided into two groups, and the wiring layers 32A and 32B of each group
On the upper side and the lower side in the figure with 1A therebetween, they are formed to extend in the y direction and to be juxtaposed in the x direction.

The wiring layer 32A formed on the upper side in FIG.
The opening 31A from the back side of the substrate 31
Each electrode of a part of the semiconductor chip 33 positioned so-called “face-down” in the printed circuit board 2
And a wiring layer for connecting to each external terminal provided on the side of the wiring layer 32B.
Is a wiring layer for connecting the other electrodes of the semiconductor chip 33 to external terminals provided on the liquid crystal display panel 1 side.

For this reason, each wiring layer 32 (32A, 32A)
B) is formed in the terminal portion 32t on the side of the semiconductor chip 33 so as to slightly protrude toward the opening 31A, and the pitch between the adjacent terminal portion 32t and the electrode pitch of the semiconductor circuit chip 33 is smaller than the pitch between the electrodes of the semiconductor circuit chip 33. In the terminal portion 32T on the printed circuit board 2 side or the liquid crystal display panel 1 side, the tip is formed flush with the side of the substrate 31, and the terminal portion 32T Is formed corresponding to the pitch of the external terminals of the printed circuit board 2 or the liquid crystal display panel 1.

Each wiring layer 3 on the side of the printed circuit board 2
The terminal portion 32T connected to each external terminal of the printed circuit board 2 in 2A is designed to be connected via, for example, solder in this embodiment. Therefore, the slits 34 for facilitating the solder dip are used. (Different from the slit featured in the present invention) is formed in the substrate 31, and the slit 34 allows most of the central portion of each wiring layer 32 </ b> A except for both ends of the terminal portion 32 </ b> T to be exposed from the back surface of the substrate 31. Is configured.

Further, in this embodiment, the printed circuit board 2
Of the respective wiring layers 32A connected to the side of the semiconductor chip 33 and the terminal portions 32T of the side connected to the semiconductor 33 chip.
At a part between t and t, another slit 35 (slit which is a feature of the present invention) formed in the substrate 31 is formed so as to extend.

That is, as described above, the printed circuit board 2
Of the wiring layer 32A connected to the semiconductor chip 33 side and the terminal section 32T connected to the printed circuit board 2 side have different pitches. The slit 35 is formed to extend in the x direction in the drawing.

The semiconductor chip 33 mounted on the substrate 31 by so-called face-down bonding
Is molded by a resin 36 formed so as to reach the peripheral surface of the substrate 31 so that an external obstacle can be avoided.

The driving circuit 3 configured as described above is similar to the driving circuit shown in FIG.
As shown in FIG. 5 which is a cross-sectional view taken along line V-V of FIG. 5, each terminal group 32T on the liquid crystal display panel 1 side Each terminal group 32T on the printed circuit board 2 side is connected to the terminal group 1T, and is connected to each terminal group 2T on the printed circuit board 2 via the solder 11.

In the liquid crystal display device described above, the slits 35 are particularly formed in the substrate 31 of the drive circuit 3 as described above, so that the wiring layer 32 provided on the surface of the substrate 31 is disconnected. Is not generated.

The reason is as follows.

That is, the printed circuit board 2 made of a synthetic resin has a large coefficient of thermal expansion with respect to the liquid crystal display panel 1 made of glass as a frame, and both sides facing each other between them are generated by the generation of cyclic heat. Are repeatedly applied to the substrate 31 of the drive circuit 3 to which is fixed.

In this case, if the wiring layer 32 is provided on the surface of the substrate 31 (in other words, formed completely in close contact with the substrate), the strain generated in the substrate 31 is not changed. 32 to lead the wiring layer 32 to disconnection.

However, by forming the slit 35 on the substrate 31, the slit 3 is formed on the surface of the substrate 31.
5 can be extended by the elasticity of the wiring layer 32 at the portion of the wiring layer 32 which crosses the slit 35 even if the strain is generated in different directions from each other at the boundary of the wiring layer 5. Can be avoided.

Further, the above-described distortion of the substrate 31 often causes disconnection in the wiring layer 32 formed obliquely, compared with the case where the wiring layer is formed substantially perpendicular to the distortion direction. It is effective to form the slit 35 in that portion.

The drive circuit 3 in the above-described embodiment has a configuration in which the connection with the printed circuit board 2 is performed via the solder 11. Needless to say, the present invention can also be applied to a configuration that performs the above.

In this case, the driving circuit 3 shown in FIG. 1 does not have the slit 34 formed on the substrate 31 for easily performing the solder dipping, and the slit 35 which is a feature of the present invention exists as it is. Will be.

[0049]

As is apparent from the above description,
According to the liquid crystal display device of the present invention, it is possible to prevent disconnection in the drive circuit.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a drive circuit in a liquid crystal display device according to the present invention.

FIG. 2 is an exploded perspective view showing one embodiment of the liquid crystal display device according to the present invention.

FIG. 3 is an equivalent circuit diagram showing one embodiment of a liquid crystal display panel and its peripheral circuits in a liquid crystal display device according to the present invention.

FIG. 4 is a plan view showing one embodiment of a liquid crystal display panel and its peripheral circuits in the liquid crystal display device according to the present invention.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

[Explanation of symbols]

3 ... Drive circuit, 31 ... Substrate, 32 ... Wiring layer, 33
…… Semiconductor chip, 35… Slit.

Claims (4)

[Claims] 1. A liquid crystal display panel, a printed circuit board disposed close to at least one side of the liquid crystal display panel, and a drive circuit disposed between the printed circuit board and the liquid crystal display panel. The driving circuit is configured such that a semiconductor chip is mounted on a flexible substrate in the form of a film, and each electrode of the semiconductor chip is laid on the substrate. In a liquid crystal display device comprising a terminal group connected to a display substrate side and a printed circuit board side, the drive circuit has a slit formed in a part of the substrate surface, and the slit is formed between the electrode of the semiconductor chip and the printed circuit board. A liquid crystal display device, wherein each wiring layer for connecting the terminal group connected to the side is formed at a position where the slit is formed. 2. The drive circuit according to claim 1, wherein each of the wiring layers extending from the semiconductor chip side to the printed board side extends obliquely with respect to the extending direction. 2. The liquid crystal display device according to claim 1, wherein the pitch on the substrate side is different, and the slit is formed on the substrate surface corresponding to the portion. 3. A semiconductor chip is mounted on a film-like flexible substrate, and electrodes of the semiconductor chip are provided on the liquid crystal display substrate side and printed via respective wiring layers formed by being laid on the substrate. In a drive circuit including a terminal group connected to the substrate side, the drive circuit has a slit formed in a part of the substrate surface, and the slit connects the semiconductor chip and the terminal group connected to a printed board side. A drive circuit, wherein each wiring layer to be connected is formed at a position where the wiring layer is formed by extending the slit. 4. A portion where each wiring layer extending from the semiconductor chip side to the printed board side extends obliquely with respect to the extending direction is provided, so that the pitch between the semiconductor chip side and the printed board side is different. 4. The driving circuit according to claim 3, wherein the slit is formed on a substrate surface corresponding to the portion.