JP3521171B2 - Liquid crystal display - Google Patents

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, for example, an active matrix type liquid crystal display device.

[0002]

2. Description of the Related Art In a liquid crystal display panel of a liquid crystal display device of this type, one of the transparent substrates arranged to face each other with a liquid crystal interposed therebetween has a liquid crystal side surface extending in the x-direction. Direction, and scanning signal lines and video signal lines that are insulated from the scanning signal lines and extend in the y direction and are arranged in parallel in the x direction are formed, and have a rectangular shape surrounded by these signal lines. The area is a pixel area.

In each of these pixel regions, a thin film transistor which is turned on by a signal (voltage) from a scanning signal line,
The pixel electrode to which the signal (voltage) from the video signal line is supplied via the turned-on thin film transistor.

And, in such a liquid crystal display panel,
A drive IC for supplying signals to the scanning signal line and the video signal line is provided as an external component, and the drive IC
Are mounted by connecting their external terminals to the liquid crystal display panel so as to face each other.

Here, as the external terminals of the liquid crystal display panel, the first metal layer and the IT arranged so as to overlap the metal layer.
And a first layer through a through hole formed in the ITO film along at least one longitudinal side of the laminated body.
It has been known that a second metal layer connected to the metal layer and a protective film covering the second metal layer are formed.

The first metal layer is composed of a metal layer having a relatively small resistance in which the scanning signal line or the video signal line is extended as it is, and the ITO film is used to reinforce its hardness. Has become. In this case, the connection resistance between the first metal layer and the ITO film becomes small. Therefore, in order to avoid this, the second metal layer is used, and the second metal layer is The structure is covered with a protective film to prevent corrosion.

[0007]

However, in a liquid crystal display device having such a structure, when a driving IC is mounted on the liquid crystal display panel so that their external terminals are connected so as to face each other, the driving is performed. It has come to be a problem that the displacement of the IC occurs.

That is, drive I is applied to the liquid crystal display panel.
Whether or not C is mounted without displacement is observed, for example, by observing the transparent substrate on which the external terminals of the liquid crystal display panel are formed from the rear surface side, and there is a displacement between the external terminals and the external terminals of the drive IC. It is done by judging whether or not.

In this case, as described above, the external terminal of the liquid crystal display panel has the protective film covering the second metal layer formed on one of the longitudinal sides thereof. If you try to place the external terminals facing each other, there is no guideline whether the arrangement is as specified,
In addition, even if they are arranged according to the regulations, they will appear to be off from the appearance.

From this, the liquid crystal display panel and the driving IC
Since it has been difficult to manage the connection of the respective external terminals, the above-mentioned problems have been pointed out.

The above-mentioned problems are explained with respect to the so-called TAB method in which the driving IC is externally attached to the liquid crystal display panel. However, the driving IC on the liquid crystal display panel
The same problem occurs in the case of a so-called COB (chip on glass) system in which the external terminal of the printed circuit board is connected to face the external terminal drawn out via the drive IC.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal display device capable of providing reliable connection between the external terminals of the liquid crystal display panel and the driving IC. It is in.

Another object of the present invention is to provide a liquid crystal display device in which the connection of the external terminals of the liquid crystal display panel on which the drive IC is mounted as it is and the printed circuit board can be made reliable. .

[0014]

In order to achieve such an object, the present invention comprises a liquid crystal display panel and a driving IC for driving the liquid crystal display panel for display.
C is mounted by connecting the external terminals to the liquid crystal display panel so as to face each other, and the external terminals of the liquid crystal display panel are arranged so as to overlap the first metal layer and this metal layer. And a first metal layer through a through hole formed in the ITO film along at least one longitudinal side of each longitudinal side of the laminated body. In a liquid crystal display device comprising a second metal layer to be connected and a protective film covering the second metal layer, the external terminal of the drive IC is opposed to the ITO film among the external terminals of the liquid crystal display panel. The second metal layer is connected so as not to face each other, and the first metal layer has a slit formed along a side portion of the external terminal of the drive IC on the second metal layer side. It is what

In the liquid crystal display device having the above structure, the side of the external terminal of the driving IC can be observed through the slit formed in the first metal layer, and the driving IC for the external terminal of the liquid crystal display panel can be observed. It becomes possible to judge whether or not the external terminal is arranged at an appropriate position.

Further, the present invention comprises a liquid crystal display panel, a drive IC mounted on the liquid crystal display panel as it is to drive the liquid crystal display panel for display, and a printed circuit board for supplying power and drive pulses to the drive IC. The printed circuit board is mounted by connecting its external terminals to the external terminals on the surface of the liquid crystal display panel, which are drawn out via the drive IC, so as to be external to the liquid crystal display panel. The terminal is composed of a laminated body of a first metal layer and an ITO film arranged so as to overlap the metallic layer, and along at least one longitudinal side portion of each longitudinal side portion of the laminated body. A liquid crystal display device comprising a second metal layer connected to the first metal layer through a through hole formed in the ITO film, and a protective film covering the second metal layer. The external terminals of the printed circuit board are connected to the ITO film of the external terminals of the liquid crystal display panel without being opposed to the second metal layer, and the external terminals of the printed circuit board are connected to the first metal layer. Is characterized in that a slit is formed along the side portion on the side of the second metal layer.

In the liquid crystal display device having such a structure, the side of the external terminal of the printed circuit board can be observed through the slit formed in the first metal layer to determine whether the printed circuit board is connected to the external terminal of the liquid crystal display panel. It becomes possible to judge whether or not the external terminal is arranged at an appropriate position.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a liquid crystal display device according to the present invention will be described below with reference to the drawings.

[Embodiment 1] The embodiment described below shows a so-called TAB type liquid crystal display device.

Schematic Overall Configuration of Liquid Crystal Display Panel FIG. 2 is a plan view showing the configuration on the liquid crystal side of one transparent substrate, which is a so-called TFT substrate, among the transparent substrates arranged to face each other with the liquid crystal interposed therebetween.

In FIG. 1, there is a TFT substrate 1, and a scanning signal line 2 extending in the x direction and juxtaposed in the y direction in the figure is formed on the surface on the liquid crystal side. Further, a video signal line 3 is formed which is insulated from the scanning signal line 2 and extends in the y direction in the drawing and is arranged in parallel in the x direction.

Then, a pixel area is formed in each rectangular area surrounded by two adjacent scanning signal lines 2 and two adjacent video signal lines 3, and display is performed in an area in which these pixel areas are aggregated. It is designed to form a region. The detailed structure of the pixel region will be described later.

The display area is shown by an area surrounded by a dot-dash line in the drawing, and another transparent substrate called a so-called filter substrate (not shown) is arranged in this region through the liquid crystal. On this filter substrate, a common electrode composed of a transparent electrode common to each pixel region is formed on the liquid crystal side surface thereof, and a color filter is formed corresponding to each pixel region.

A sealing material is arranged between the TFT substrate 1 and a side portion corresponding to the outer contour of the filter substrate (the one-dot chain line in the figure), and the liquid crystal is sealed between the substrates by this sealing material. It is like this.

Then, one end of the scanning signal line 2 extends to the peripheral portion of the TFT substrate 1 beyond the sealing material (the one-dot chain line portion in the figure), and at this extended portion, the external terminal 2A is provided.
Are configured.

The external terminal 2A serves as a terminal for supplying a scanning signal to the scanning signal line 2 from a driving IC which is an external component, and its detailed structure will be described later.

Similarly, one end of the video signal line 3 extends to the peripheral portion of the TFT substrate 1 beyond the sealing material (the one-dot chain line portion in the figure), and at this extended portion, the external terminal 3A is provided.
Are configured.

The external terminal 2A also serves as a terminal for supplying a video signal to the video signal line 3 from a drive IC which is an external component.

Structure of Pixel Area FIG. 3 is a plan view showing a detailed structure of the pixel area.

Each member will be described below in the order of manufacturing steps.

First, the scanning signal line 2 extending in the x direction in the figure.
Are formed. The scanning signal line 2 is made of, for example, Cr. In this case, it is needless to say that the material is not limited to this, and may be a metal such as Al.

The scanning signal line 2 has an extending portion extending in the direction of the pixel region in the lower left portion of the pixel region in the figure, and this extending portion is a thin film transistor TFT described later.
Of the gate electrode 2G.

The TF having the scanning signal line 2 formed in this way
An insulating film (not shown) made of, for example, a silicon nitride film is formed over the entire display region of the T substrate 1.

This insulating film serves as an interlayer insulating film for the scanning signal line 2 of the video signal line 3 in the crossing region of the scanning signal line 2 and the video signal line 3 which will be described later, and also in the formation region of the thin film transistor TFT which will be described later. , It functions as a gate insulating film, and further as a dielectric film in a formation region of an additional capacitance element Cadd described later.

Then, an island-shaped semiconductor layer 4 is formed on the upper surface of the insulating film in the formation region of the thin film transistor TFT. The semiconductor layer 4 is formed so as to groin the gate electrode 2G.
The gate electrode 2G on the surface of the
By forming the drain electrode and the source electrode which are arranged to face each other, a so-called inverted staggered structure FET is formed.

In this case, the drain electrode and the source electrode are formed simultaneously with the formation of the video signal line 3 described later.

Further, a pixel electrode 5 is formed on the upper surface of the insulating film in the pixel region except the formation region of the thin film transistor TFT. This pixel electrode 5 is I
It is made of a TO (Indium-Tin-Oxide) film, and a part of it extends so as to be superposed on the scanning signal line 2.

The scanning signal line 2 on which the pixel electrode 5 is superimposed is
An additional capacitance which is another adjacent scanning signal line 2 different from the scanning signal line 2 for driving the thin film transistor TFT via the gate electrode 2G thereof, and an insulating film interposed between them in this portion being a dielectric film. The element Cadd is formed. The additional capacitance element Cadd is provided to store the video signal supplied to the pixel electrode 5 for a long time when the thin film transistor TFT is turned off.

A video signal line 3 extending in the y direction in the figure is formed. The video signal line 3 is made of, for example, Al.
Part of which is extended and formed integrally with the drain electrode of the thin film transistor TFT, and at the same time, the source electrode of the thin film transistor TFT is connected to the pixel electrode 5 and is formed at the same time. It has become. The material forming the video signal line 3 is not limited to Al, and for example, Cr, M
Of course, it may be o or an alloy thereof.

Further, a protective film (not shown) made of, for example, a silicon nitride film is formed on the entire surface thus processed. This protective film is provided to avoid direct contact of liquid crystal with the thin film transistor TFT.

Configuration of External Terminal FIG. 1A is a detailed plan view of the external terminal 2A in the scanning signal line 2, showing the details of the portion enclosed by the dotted line frame A in FIG. In addition, FIG. 1B is bb of FIG.
Figure 3 shows a cross-sectional view along the line.

First, the scanning signal line 2 is formed on the surface of the TFT substrate 1.
There is a first metal layer 20 extending as is. And
In this embodiment, in particular, the slit 20a is formed along one longitudinal side of the longitudinal side (side parallel to the x direction in the drawing) of the first metal layer 20. The slit 20a may be formed as a series of connected holes, but in this embodiment, a plurality of slits having a short length are intermittently provided on the same straight line. This is to avoid an increase in electrical resistance in the direction orthogonal to the longitudinal direction.

The IT formed on the surface of the first metal layer 20 at the same time as the pixel electrode 5 is formed.
An O film 21 is formed. The ITO film 21 is formed by applying the first metal layer 20 made of a relatively soft material to the ITO film 2.
It is formed to reinforce by 1 and to prevent corrosion of the first metal layer 20. Therefore, the ITO film 21 is formed so as to completely cover the first metal layer 20.

A contact hole 21a is formed in the ITO film 21 along one of the longitudinal sides of the first metal layer 20. Here, the contact hole 21a is provided closer to the longitudinal side than the slit 20a, and the second metal layer 22 connected to the first metal layer 20 is formed through the contact hole 21a.

Since the second metal layer 22 has a large connection resistance between the first metal layer 20 and the ITO film 21, it is provided to alleviate it. As a result, the current supplied from the ITO film 21 is not applied to the second metal layer 2
It becomes easy to flow into the first metal layer 20 via the second layer 2.

In this case, the second metal layer 22 is formed so that its width is small and does not cover at least the slit 20a.

A protective film 23 is formed so as to cover the second metal layer 22. This protective film 23 is
For example, the protective film is formed at the same time when the protective film is formed in the display area. The protective film 23 is provided to prevent corrosion of the second metal layer 22.

Structure of Driving IC As shown in FIG. 4, the driving IC 7 is a semiconductor device formed by a so-called film carrier method, and an IC 72 is mounted on the film-shaped insulating substrate 71 at substantially the center thereof. It is led out to the external terminal 74 as it is through the wiring layer 73 formed on the back surface of the insulating substrate 71.

Mounting the IC 72 on the insulating substrate 71
The electrodes are bonded to the wiring layer 73 exposed from the opening 71A formed in the center of the insulating substrate 71 with the IC 72 face down.

The drive IC 7 thus constructed is connected in a state where its external terminals are arranged so as to face the corresponding external terminals 2A of the scanning signal line 2 of the liquid crystal display panel, for example.

Although the arrangement of the external terminals 2A and 3A is not clearly shown in FIG. 2, the driving IC 7 is actually used.
As shown in FIG. 4, the external terminals are arranged close to each other in a predetermined number (that is, arranged in groups), and one drive IC 7 is provided for each group of external terminals. Will be installed.

In the drive IC 7, in addition to the external terminal 74 connected to the external terminal 2A of the liquid crystal display panel, I
A similar external terminal is provided on the opposite side of the external terminal 74 with the C72 in between, and this external terminal is adapted to be connected to a printed circuit board (not shown).

Mounting of Driving IC on Liquid Crystal Display Panel FIG. 5 shows that when the external terminal 2A of the liquid crystal display panel and the external terminal 74 of the driving IC 7 are connected, the respective external terminals 2A,
FIG. 5 is a diagram showing a case where it is determined whether or not 74 is in an appropriate position, and corresponds to a cross-sectional view taken along line VV of FIG. 4.

The protective film 23 is a region that does not contribute to the connection.
When the external terminal 74 on the drive IC 7 side is appropriately positioned so as to avoid the portion formed by
The long side 74a on the protective film 23 side of No. 4 can be recognized through the slit 20a of the first metal layer 20 (the visual direction is the arrow direction in the drawing).

On the other hand, when the drive IC 7 is displaced to the left in the figure, the external terminal 74 cannot be recognized through the slit 20a, and the drive I
When C7 is displaced rightward in the drawing, the external terminal 74 can be recognized over the entire area of the slit 20a.

According to the liquid crystal display device according to the present embodiment, the liquid crystal display panel of the liquid crystal display panel can be observed depending on whether the side portion of the external terminal 74 of the driving IC 7 can be observed through the slit 20a formed in the first metal layer 20. It becomes possible to determine whether or not the external terminal 74 of the drive IC 7 with respect to the external terminal 2A is arranged at an appropriate position.

[Embodiment 2] The embodiment described below shows a so-called COG type liquid crystal display device.

Configuration of Main Part of Liquid Crystal Display Device FIG. 6 is a perspective view showing a main part of the liquid crystal display device.

In the figure, there is a liquid crystal display panel having the TFT substrate 1 and the filter substrate 10 as envelopes. The structure of the TFT substrate 1 and the structure of the filter substrate 10 in the display section of this liquid crystal display panel are the same as those shown in, for example, the first embodiment.

A major difference between the liquid crystal display panel and the liquid crystal display panel shown in the first embodiment is that the liquid crystal display panel is driven to be displayed on the surface of the TFT substrate 1 where the filter substrate 10 is not covered (peripheral portion). Drive IC for
11A and 11B are mounted as they are.

From this, the scanning signal line 2 extending beyond the sealing material is connected to the driving IC 11A through the TFT.
The peripheral portion of the substrate 1 is reached and the external terminal 2T (see FIG. 7) is configured in this peripheral portion. Similarly, the video signal line 3 extending beyond the sealing material reaches the peripheral portion of the TFT substrate 1 through the connection with the driving IC 11B and constitutes an external terminal (not shown) in this peripheral portion. ing.
Here, the drive ICs 11A and 11B are single ICs.
Is connected to the scanning signal line through the anisotropic conductive film with the surface on which the electrode is formed facing down.

Incidentally, FIG. 7 shows the scanning signal line 2 and the driving IC 1.
1A is a plan view showing details of an external terminal 2T. FIG.

The external terminal 2T of the scanning signal line 2 via the drive IC 11A is opposed to the external terminal of the flexible printed board 13A for supplying power and drive pulse to the drive IC 11A, and an anisotropic conductive film is interposed therebetween. It is supposed to be connected. An external terminal (not shown) of the video signal line 3 via the drive IC 11B is opposed to an external terminal of the flexible printed circuit board 13B for supplying power and drive pulses to the drive IC 11B, and is an anisotropic conductive film. It is designed to be connected via.

Structure of External Terminal 2T This external terminal 2T has the same structure as the external terminal 2A in the first embodiment, and specifically has the structure shown in FIG.

The external terminal 2T is also provided at the external terminal (not shown) of the video signal line 3 via the drive IC 11B.
It has the same configuration as.

According to the liquid crystal display device according to the present embodiment, the liquid crystal is displayed depending on whether the side portions of the external terminals of the flexible printed boards 13A and 13B can be observed through the slits 20a formed in the first metal layer 20. Flexible printed circuit board 1 for the external terminal 2T of the display panel
It becomes possible to judge whether or not the external terminals of 3A and 13B are arranged at appropriate positions.

[0067]

As is apparent from the above description,
According to the liquid crystal display device of the present invention, the connection between the liquid crystal display panel and the external terminals of the drive IC or the printed circuit board can be made reliable.

[Brief description of drawings]

FIG. 1 is a main part configuration diagram showing an embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is an overall schematic plan view showing an embodiment of a TFT substrate of a liquid crystal display device according to the present invention.

FIG. 3 is a configuration diagram showing an embodiment of a pixel region of a liquid crystal display device according to the present invention.

FIG. 4 is a drive I provided in the liquid crystal display device according to the present invention.
It is explanatory drawing which shows one Example of C.

FIG. 5 is an explanatory diagram illustrating an effect of the liquid crystal display device according to the present invention.

FIG. 6 is a perspective view of a main part showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 7 is a main part plan view showing another embodiment of the liquid crystal display device according to the present invention.

[Explanation of symbols]

2A, 2T ... External terminals (of liquid crystal display panel), 7 ... Driving IC, 20 ... First metal layer, 20a ... Slit, 21 ... I
TO film, 22 ... Second metal layer, 23 ... Protective film, 74 ... External terminals (of drive IC), 13A, 13B ... Flexible printed circuit board.

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-6-214247 (JP, A) JP-A-8-313924 (JP, A) JP-A-7-13183 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G02F 1/1345 G02F 1/1343 G02F 1/1368

Claims (2)

(57) [Claims] 1. A liquid crystal display panel and a drive IC for driving the display of the liquid crystal display panel, wherein the drive IC is mounted on the liquid crystal display panel by connecting their external terminals so as to face each other. The external terminal of the liquid crystal display panel is composed of a laminated body of a first metal layer and an ITO film arranged so as to overlap the metal layer, and at least one of the longitudinal side portions of the laminated body is Liquid crystal display including a second metal layer connected to the first metal layer through a through hole formed in the ITO film along one longitudinal side, and a protective film covering the second metal layer. In the device, an external terminal of the driving IC is connected to the ITO film of the external terminal of the liquid crystal display panel without being opposed to the second metal layer, and the external terminal of the driving IC is connected to the first metal layer. A liquid crystal display device, wherein slits are formed along a side of the terminal on the second metal layer side. 2. A liquid crystal display panel, a drive IC mounted on the liquid crystal display panel as it is to drive the liquid crystal display panel for display, and a printed circuit board for supplying power and drive pulses to the drive IC. The board is mounted by connecting its external terminals to the external terminals on the surface of the liquid crystal display panel, which are drawn out through the drive IC, so that the external terminals of the liquid crystal display panel are It is composed of a laminated body of one metal layer and an ITO film arranged so as to overlap with this metal layer, and the ITO film is formed along at least one longitudinal side portion of each longitudinal side portion of the laminated body. A liquid crystal display device comprising: a second metal layer connected to the first metal layer through a formed through hole; and a protective film covering the second metal layer. The external terminals of the printed circuit board are connected to the ITO film of the external terminals of the liquid crystal display panel without being opposed to the second metal layer, and the first metal layer is connected to the second external terminal of the printed circuit board. A liquid crystal display device, wherein slits are formed along a side portion on the metal layer side.