JPH09243999A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high contrast and good display quality by preventing the crosstalk occurring in the fluctuation in pixel voltage by the leak current of a thin-film transistors (TFT) 3. SOLUTION: Data signal lines 1a, 1b are disposed to intersect orthogonally with a scanning signal line 2. The intersected part of the data signal line 1a and the scanning signal line 2 is provided with the TFT 3. A pixel electrode 8 is superposed via a second interlayer insulating film 7 on the data signal lines 1a, 1b. At this time, the superposing areas S1, S2 of the pixel electrode 8 and the data signal line la are S1<S2. As a result, the coupling capacitors Csd1, Csd2 generated in the superposed parts of the pixel electrode 8 and the data signal lines 1a, 1b are Csd1<Csd2. When the data signals of a reverse polarity are supplied onto the data signal lines 1a, 1b, the fluctuation quantity of the pixel voltage by the coupling capacitors arises and the decreased component of the pixel voltage by the leak current of the TFT 3 is compensated.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a switching element such as a thin film transistor (TFT).
The present invention relates to an active matrix drive type liquid crystal display device using an ansistor.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been widely used mainly in computer displays, from AV (Audio Visual) to amusement fields. In the future, in order to support such a variety of media, there is a demand for higher definition and higher brightness of the liquid crystal display device. In order to achieve such an object, various attempts have been hitherto made, for example, by improving the aperture ratio to improve the light utilization efficiency.

FIG. 4 shows a planar structure of one pixel for driving liquid crystal in an active matrix drive type liquid crystal display device. In this pixel portion, the data signal lines 51a and 51b are provided so as to be orthogonal to the scanning signal line 52, and a switching element such as the thin film transistor 5 is provided at the intersection of the data signal line 51a and the scanning signal line 52.
3 are provided. Further, the pixel portion is provided with a storage additional capacitor 54 for preventing the pixel voltage from decreasing due to a leak current of the thin film transistor 53 and the like.

A black matrix (not shown) is generally provided on a counter substrate (not shown) side facing a substrate (hereinafter, simply referred to as a TFT substrate) on which the thin film transistor 53 is provided. Therefore, in the conventional structure,
Considering the misalignment between the TFT substrate and the counter substrate,
A bonding margin 55 is provided. For this reason,
When the TFT substrate and the counter substrate are bonded together, the openings 56 of the black matrix are formed inside the pixel electrodes 57.

Here, the larger the above-mentioned bonding margin 55, the greater the decrease in the aperture ratio. Therefore, in order to improve the aperture ratio, it is desirable to reduce the above-mentioned bonding margin 55. However, when the bonding margin 55 is reduced, both substrates must be bonded with high accuracy, and this method is actually difficult.

Therefore, in order to improve the aperture ratio, for example, JP-A-6-230422 and JP-A-6-27.
Japanese Patent No. 4130 discloses a method in which, as shown in FIGS. 5A and 5B, the pixel electrode 66 is superposed on the data signal lines 61a and 61b via the second interlayer insulating film 69. ing. That is, in this method, as shown in FIG. 5B, the first interlayer insulating film 68, the data signal line 61a (or the data signal line 61b), the second interlayer insulating film 69, and the pixel electrode 66 are formed on the substrate 67. Are formed in this order. Note that, for convenience of explanation, FIG.
It is assumed that the planar structure of the pixel is shown, and FIG.
5B is a sectional view taken along the line BB ′ of FIG.

According to this method, even if a slight misalignment between the TFT substrate and the counter substrate occurs in the left-right direction, the data signal lines 61a and 61b themselves act as a light-shielding film, so that light leakage can be prevented. You can Therefore,
In the above method, it is not necessary to provide at least the bonding margin 55 (see FIG. 4) in the left-right direction, which is conventionally required, and it is possible to improve the aperture ratio in the left-right direction at least.

However, in the above method, the pixel electrode 66 is connected to the data signal lines 61a and 61b via the second interlayer insulating film 69.
The pixel electrode 66 and the data signal line 61 are overlapped on top of each other.
The coupling capacitances Csd1 'and Csd are provided in the overlapping portion with a and 61b.
2'is generated, and the coupling capacitances Csd1 'and Cs are generated.
There is a problem that the pixel voltage Vd fluctuates via d2 '.

Here, an equivalent circuit of the pixel section shown in FIG. 5A is shown in FIG. In this equivalent circuit, the coupling capacitance C
If the sum of sd1 'and Csd2' is Csd, the pixel capacitance (sum of the liquid crystal capacitance CLC and the additional storage capacitance Cs) is Cp, and the data signal voltage fluctuation amount is ΔVs, the pixel voltage fluctuation amount ΔV
d is represented by the following equation (1).

ΔVd = {Csd / (Cp + Csd)} × ΔVs (1) This fluctuation of the pixel voltage Vd is caused when the scanning of the data signal is performed from the upper part of the screen to the lower part of the screen. Few, the largest at the bottom of the screen.

On the other hand, the pixel voltage fluctuation amount ΔVd is shown in FIG.
The following is a description with reference to the waveform diagrams shown in (a) to FIG. 7 (c). 7 (a) and 7 (b),
FIG. 7 shows waveforms of data signals applied to the adjacent data signal lines 61a and 61b (see FIG. 5A).
(C) shows the waveform of the pixel voltage Vd when the data signal is applied.

In the method of overlapping the pixel electrode 66 (see FIG. 5A) and the data signal lines 61a and 61b as described above, as shown in FIG. 7C, the coupling capacitances Csd1 'and Csd1' and Csd1 '.
A pixel voltage fluctuation amount ΔVd (Csd) due to sd2 ′ is generated. Note that, for easy understanding of the description here, the coupling capacitance Cs from the adjacent data signal lines 61a and 61b.
The influence of capacitances other than d1 'and Csd2' is omitted.

By the way, when the variation amount ΔVd of the pixel voltage Vd becomes large, a luminance gradient along the data signal line, that is, crosstalk in which the luminance of the pixel gradually changes from the upper portion to the lower portion of the screen occurs. The reason is as follows.

Off resistance Roff of the thin film transistor itself
FIG. 8 shows an equivalent circuit of a pixel in consideration of the source-drain capacitance CSD. From this figure, the off resistance Ro
Through ff and the source-drain capacitance Csd, it can be seen that the potential of the data line affects the charge amount of the thin film transistor side electrode of the liquid crystal capacitance CLC which is the pixel electrode.

The magnitude of the off resistance Roff is less than or equal to the off resistance Roff, and the source-drain capacitance Csd.
It is not possible to say unequivocally as to what degree or more the deterioration of display quality will start to occur. This is because the degree of deterioration depends not only on the liquid crystal material of the display body, the number of gradations that can be displayed and the display pattern, but also on the purpose of use as a display device. Therefore, the off-resistance Roff and the source-drain capacitance Cs
There can be no absolute criterion for d.

Next, an example of a non-negligible defect due to the source-drain capacitance Csd of the thin film transistor will be described with reference to FIGS. 9 (a) and 9 (b).

FIG. 9A shows a display screen on which a display pattern in which the problem remarkably occurs is displayed.
In the central window area E, a display corresponding to predetermined display data (for example, display data 1) is uniformly formed over the entire surface. A region A around the window region E,
In B, C, and D, as shown in FIG. 9B, display of luminance corresponding to two kinds of predetermined display data (for example, display data 1 and display data 2) is alternately performed for each pixel. The so-called checkered pattern appears.

In such a case, as shown in FIG. 9A, the brightness of the regions C and D above and below the window region E changes as a whole. This is because the average value of the potential of the data line is different between the inside and the outside of the window region E, so that the influence on the potential of the pixel electrode is different.

Here, in the display state shown in FIG.
The movement of the average potential of a certain data line DL in the window region E and the regions C and D above and below the window region E, and the variation of the charging potential of the pixels X and Y on the data line DL are shown over two frame periods. As shown in FIG.

As shown in FIG. 10, the pixel X in the area C above the window area E (see FIG. 9) and the pixel Y in the area D below the window area E (see FIG. 9) Data line DL at
The influence of the average potential of is reversed. That is, pixel X
Then, this is affected by the average potential of the data line DL in the window region E in the same frame as the charged frame, and in the pixel Y, the data line in the window region E in the frame next to the charged frame. This is because it is affected by the average potential of DL. As a result, the brightness of the areas C and D above and below the window area E changes overall. This becomes more remarkable as the fluctuation of the pixel voltage increases.

Therefore, the above publication attempts to cancel the pixel voltage fluctuations by applying signals of opposite polarities to adjacent data signal lines to prevent the occurrence of crosstalk as described above. Hereinafter, for convenience of explanation, FIG.
A case where the above method is applied to the pixel portion shown in FIGS. 5A and 5B will be described.

That is, data signals of opposite polarities as shown in FIGS. 11A and 11B are applied to the data signal line 6.
1a and 61b (see FIG. 5B), the pixel voltage fluctuation amount due to the coupling capacitance Csd1 ′ (see FIG. 5B) between the data signal line 61a and the pixel electrode 66 (see FIG. 5B). ΔVd1 becomes ΔVd1 = {Csd1 ′ / (Cp + Csd)} × (−ΔVs) (2), and similarly, the coupling capacitance Csd2 ′ between the data signal line 61b and the pixel electrode 66 (see FIG. 5B). The pixel voltage fluctuation amount ΔVd2 due to: ΔVd2 = {Csd2 ′ / (Cp + Csd)} × ΔVs (3) Therefore, the pixel voltage fluctuation amount ΔVd (Csd) caused by the coupling capacitance is ΔVd (Csd) = ΔVd1 + ΔVd2 = {(Csd2-Csd1) / (Cp + Csd)} × ΔVs from the above equations (2) and (3). (4) Therefore, if Csd1≈Csd2, ΔVd (Csd) = 0 according to the above equation (4).

That is, according to the above method, by providing the data signals having the opposite polarities to the adjacent data signal lines 61a and 61b, as shown in FIG.
Pixel voltage fluctuation amount ΔV caused by d1 ′ and Csd2 ′
d (Csd) is canceled and the coupling capacitances Csd1 ', C
The influence of sd2 'is eliminated.

[0024]

However, the actual pixel voltage fluctuation amount ΔVd is as shown in FIGS. 7C and 11C in addition to the pixel voltage fluctuation amount ΔVd (Csd) generated by the coupling capacitance. The pixel voltage fluctuation amount ΔVd (Ioff) due to the leak current of the thin film transistor is also affected. That is, the actual pixel voltage fluctuation amount ΔVd is ΔVd = ΔVd (Csd) + ΔVd (Ioff) (5). This effect is particularly great when the storage additional capacitance is reduced in order to improve the aperture ratio, for example. Further, when a liquid crystal display device is used for a light valve for a projector, the leak current increases due to the influence of light and temperature, so that the pixel voltage fluctuation amount ΔVd (Iof
f) becomes a problem. Therefore, in the above method, it is not possible to consider the pixel voltage fluctuation amount ΔVd (Ioff), and as a result, there is a problem that crosstalk occurs even if the pixel voltage fluctuation amount ΔVd (Csd) is canceled.

The present invention has been made to solve the above problems, and its purpose is to obtain a pixel voltage fluctuation amount ΔVd.
(Ioff) is taken into consideration to suppress the occurrence of crosstalk,
An object of the present invention is to provide a liquid crystal display device having a high contrast and capable of obtaining a good display quality.

[0026]

In order to solve the above-mentioned problems, a liquid crystal display device according to a first aspect of the present invention includes a plurality of first signal lines and a plurality of first signal lines orthogonal to the first signal lines. A second signal line, a thin film transistor provided at an intersection of the first signal line and the second signal line, and a pixel electrode stacked on the adjacent first signal line via an insulating film. In the liquid crystal display device having the above, by supplying signals of opposite polarities to the adjacent first signal lines, the amount of decrease in pixel voltage caused by the leak current of the thin film transistor can be reduced,
The pixel electrode is superposed on the adjacent first signal line through an insulating film so that the pixel voltage fluctuation amount caused by the difference in coupling capacitance between the first signal line and the pixel electrode can be compensated. It is characterized by being.

According to the above configuration, by supplying signals of opposite polarities to the adjacent first signal lines, pixel voltage fluctuations having different signs are generated in the pixel electrodes.
The pixel voltage fluctuation due to the total coupling capacitance is suppressed. Further, according to the above configuration, the decrease amount of the pixel voltage caused by the leak current of the thin film transistor is compensated by the pixel voltage fluctuation amount caused by the difference in the coupling capacitance between the first signal line and the pixel electrode. . As a result, for example, a sufficient pixel voltage is supplied even in the lower part of the screen.

In other words, conventionally, in order to obtain a good display, signals of opposite polarities are supplied to the adjacent first signal lines to cause pixel voltage fluctuations of the same absolute value but different signs. Only the pixel voltage fluctuation due to the coupling capacitance is canceled. However, in reality, the pixel voltage decreases due to the leak current of the thin film transistor. Therefore, in the related art, even if the pixel voltage fluctuation due to the coupling capacitance is canceled, the amount of decrease in the pixel voltage caused by the leak current of the thin film transistor is not compensated, so that the pixel voltage is insufficiently supplied in the lower part of the screen, for example. Was becoming. As a result, crosstalk occurs in which the luminance of pixels gradually changes from the upper part of the screen to the lower part.

However, according to the above configuration, the pixel voltage variation due to the coupling capacitance is suppressed and the pixel voltage variation due to the leakage current of the thin film transistor compensates for the pixel voltage variation due to the difference in the coupling capacitance. A sufficient pixel voltage is supplied even in the lower part of the screen.
As a result, it is possible to obtain a display with uniform brightness over the entire screen.

Therefore, according to the above structure, by overlapping the pixel electrode on the adjacent first signal line with the insulating film interposed therebetween, the aperture ratio can be increased and the crossing caused by the leak current of the thin film transistor can be achieved. Talk can be prevented. As a result, it is possible to surely obtain a good display with high contrast.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

Before explaining the structure of the pixel portion of the active matrix driving type liquid crystal display device of the present invention, although not shown, a thin film transistor (TFT) is not shown.
Substrate on which the Transistor is installed (hereinafter referred to as TFT
The structure of the substrate will be described below.

The TFT substrate is composed of a transparent glass substrate or a quartz substrate, a gate drive circuit, a source drive circuit and a TFT array section formed on the substrate. The gate driving circuit is composed of a shift register and a buffer, and the source driving circuit is composed of a shift register, a buffer, and an analog switch for sampling a video line.

In the TFT array portion, a large number of scanning signal lines extending from the gate driving circuit are arranged in parallel, and a large number of data signal lines extending from the source driving circuit are connected to the scanning signal lines. They are arranged so as to be orthogonal to each other. Further, an additional capacitance common line is arranged in parallel with the scanning signal line.

A thin film transistor as a switching element is provided at the intersection of the scanning signal line and the data signal line. A pixel electrode connected to the drain electrode of the thin film transistor and an additional capacitor are arranged in a rectangular area surrounded by two scanning signal lines adjacent to each other and two data signal lines adjacent to each other. Thus, one pixel is formed. The detailed configuration of this one pixel will be described later. The gate electrode of the thin film transistor is connected to the scanning signal line, and the source electrode of the thin film transistor is connected to the data signal line.

A liquid crystal is sealed between the pixel electrode and the counter electrode formed on the counter substrate to form a pixel. At this time, the additional capacitance common line is connected to the electrode having the same potential as the counter electrode.

Next, in the liquid crystal display device of the present invention, FIG. 1A shows a plan view of one pixel for driving liquid crystal. In this pixel portion, the data signal lines 1a and 1b (both are first signal lines) are provided so as to be orthogonal to the scanning signal line 2 (second signal line), and the data signal line 1a and the scanning signal line 2 are provided.
A thin film transistor 3 as a switching element is provided at the intersection with and. Further, the pixel portion is provided with a storage additional capacitor 4 for preventing a decrease in pixel voltage due to a leak current of the thin film transistor 3 or the like.

Although not shown, the thin film transistor 3 is manufactured by the following method.

First, a polycrystalline silicon thin film to be an active layer is formed to a thickness of 40 nm to 80 nm on an insulating substrate. In addition, sputtering or CVD (Chemical Vap
or Deposition) method is used to obtain a film thickness of 80 nm to 150 n
m gate insulating film is formed.

Then, in the above-mentioned polycrystalline silicon thin film, P ⁺ is added to 1 × in an additional capacitance portion which will later form an additional capacitance.
Ions are implanted at a concentration of 10 ¹⁵ (cm ^-2 ) to obtain n ⁺ type,
A gate electrode and an additional capacitor upper electrode are formed by using metal or low-resistance polycrystalline silicon, and patterned into a predetermined shape. Then, in order to determine the conductivity type of this thin film transistor, P ^{+ is set} to 1 from above the gate electrode.
Ions are implanted at a concentration of × 10 ¹⁵ (cm ⁻² ), and the lower portion of the gate electrode, that is, a region not ion-implanted is used as a channel, and the ion-implanted regions on both sides are used as a source and a drain, respectively.

Further, after forming the first interlayer insulating film on the entire surface of the substrate using silicon oxide (SiO ₂ ) or silicon nitride (SiN _x ), contact holes are formed to reduce the resistance of aluminum (Al) or the like. The data signal lines and the stacked electrodes are formed using metal.

Then, similar to the above, silicon oxide (Si
O ₂ ) or silicon nitride (SiN _x ) is used to form a second interlayer insulating film on the entire surface of the substrate, and then a contact hole is formed, and the contact hole is covered to cover indium oxide (ITO; Indium Tin Oxide), etc. A pixel electrode made of the transparent conductive film is formed to complete a thin film transistor.

In this embodiment, polycrystalline silicon is used as the active layer, but the active layer is not limited to this, and amorphous silicon may be used instead of polycrystalline silicon.

Next, a sectional view taken along the line AA 'in FIG. 1A is shown in FIG. The first interlayer insulating film 6 and the data signal line 1a (or the data signal line 1b) are formed in this order on the transparent substrate 5. Then, in the present embodiment, the pixel electrode 8 is overlapped with the data signal lines 1 a and 1 b via the second interlayer insulating film 7. At this time, in the figure (a), if the overlapping area of the pixel electrode 8 and the data signal line 1a is S1 and the overlapping area of the pixel electrode 8 and the data signal line 1b is S2, S1 <S2. As a result, the coupling capacitances Csd1 and Csd2 (see FIG. 7B) generated in the overlapping portion of the pixel electrode 8 and the data signal lines 1a and 1b are Csd1 <Csd2.

From the equations (2) and (3) described in the "Prior Art" section, the influence from the coupling capacitance Csd1 is provided in the direction of decreasing the pixel voltage Vd, that is, on the counter electrode side (not shown). In addition, the potential difference between the common electrode and the pixel electrode 8 is reduced. Also, the coupling capacitance Csd2
From the direction of increasing the pixel voltage Vd, that is,
There is a direction to increase the potential difference between the common electrode and the pixel electrode 8. Therefore, the reason why the overlapping area S2 is larger than the overlapping area S1 as described above is that the coupling capacitance C
Pixel voltage fluctuation amount Δ caused by the difference between sd1 and Csd2
This is because Vd (Csd) compensates for a decrease in the pixel voltage fluctuation amount ΔVd (Ioff) due to the leak current of the thin film transistor 3.

When the data signal is scanned from the top to the bottom of the screen, it is the bottom of the screen rather than the top of the screen that is more affected by variations in pixel voltage. By suppressing the pixel voltage fluctuation amount in the lowermost pixel, crosstalk in the entire screen can be suppressed. Therefore, in the following description, the pixel at the bottom of the screen is used as a reference.

When data signals of opposite polarities as shown in FIGS. 2 (a) and 2 (b) are applied to the data signal lines 1a and 1b, respectively, a pixel as shown in FIG. 2 (c) is obtained. The waveform of the voltage Vd is obtained. From this waveform diagram, the amount of decrease in the pixel voltage due to the leakage current of the thin film transistor 3 (see FIG. 1A) shows that the coupling capacitors Csd1 and Csd2 (see FIG. 1).
Pixel voltage fluctuation amount ΔVd caused by the difference (see (b))
It can be seen that it is compensated by (Csd). That is, in the liquid crystal display device of the present embodiment, the pixel voltage fluctuation amount ΔVd (Ioff) due to the leak current of the thin film transistor 3 is
The pixel voltage fluctuation amount ΔVd (Csd) cancels.

That is, in FIG. 1 (a) and FIG. 1 (b), in the conventional case, even if the data signal of the opposite polarity as described above is applied to the data signal lines 1a and 1b, the pixel electrode 8 and the data signal line 1a are not provided. Since the overlapping areas S1 and S2 with 1b are equal to each other, the pixel voltage fluctuation amount ΔVd (Csd) due to the coupling capacitors Csd1 and Csd2 can be eliminated,
It was not possible to eliminate the pixel voltage fluctuation amount ΔVd (Ioff) due to the leak current of the thin film transistor 3.
However, according to the above configuration, by setting S1 <S2, Csd1 <Csd2, and the pixel voltage fluctuation amount ΔVd.
(Ioff) can be canceled by the pixel voltage fluctuation amount ΔVd (Csd). As a result, the RMS voltage applied to the liquid crystal at the bottom of the screen becomes substantially the same as the RMS voltage applied to the liquid crystal near the top of the screen.

Therefore, according to the above structure, the pixel electrode 8 and the data signal lines 1a and 1b are overlapped with each other, and the overlapping area is set to S1 <S2. Can cancel even the pixel voltage fluctuation amount ΔVd (Ioff) that could not be canceled. Therefore, the liquid crystal display device of the present invention
Since a sufficient voltage is applied to the liquid crystal even at the bottom of the screen, crosstalk caused by pixel voltage fluctuations can be suppressed, and good display quality with high contrast can be obtained.

As in the present embodiment, the overlapping areas S1 and S2 of the pixel electrode 8 and the data signal lines 1a and 1b are set to S1.
<S2, as long as the pixel voltage fluctuation amount ΔVd (Ioff) is canceled, the shape of the overlapping portion is not particularly limited.

For example, as shown in FIG. 3, the lengths of the overlapping portions of the pixel electrodes 7 and the data signal lines 1a and 1b in the short direction are made equal, and the lengths in the long side direction are changed, so that S1 <S2. It doesn't matter. Even in this case, it goes without saying that the same effect as the present embodiment can be obtained.

In the present embodiment, the pixel at the bottom of the screen is used as a reference, but the above-mentioned measures, that is, the overlapping areas S1 and S2 are set to S1 <S2, and the pixel voltage fluctuation amount ΔVd (Ioff is set. ) May be canceled in the pixel in the upper part of the screen.

For example, the coupling capacitors Csd1 and Csd2 are
While satisfying S1 <S2 so that Csd1 <Csd2, S2 is increased from the top of the screen toward the bottom.
It is also possible to change (increase or decrease) S1 little by little to form a pixel. As a result, the same effect as that of the present embodiment can be obtained.

[0054]

The liquid crystal display device according to the invention of claim 1
As described above, by supplying signals of opposite polarities to the adjacent first signal lines, the reduction amount of the pixel voltage caused by the leak current of the thin film transistor can be reduced by the first
The pixel electrode is superposed on the adjacent first signal line via an insulating film so as to be compensated for by a pixel voltage fluctuation amount caused by a difference in coupling capacitance between the signal line and the pixel electrode. It is a composition.

Therefore, the aperture ratio can be increased by stacking the pixel electrode on the adjacent first signal line via the insulating film. Further, according to the above configuration, the pixel voltage variation due to the coupling capacitance is suppressed, and the pixel voltage variation due to the leakage current of the thin film transistor is compensated by the pixel voltage variation amount due to the coupling capacitance difference. Also in this case, a sufficient pixel voltage is supplied. As a result, it is possible to obtain a display having a uniform brightness on the entire screen. Therefore, according to the above configuration, it is possible to prevent the crosstalk due to the leak current of the thin film transistor. Further, as a result, it is possible to obtain an effect that a good display with high contrast can be surely obtained.

[Brief description of drawings]

1A is a plan view showing a structure of one pixel of a liquid crystal display device according to the present invention, and FIG. 1B is a sectional view taken along the line AA ′ in FIG.

FIGS. 2A and 2B are waveform diagrams showing waveforms of data signals having opposite polarities supplied to adjacent data signal lines in the one pixel, and FIG. It is a waveform diagram which shows the waveform of the pixel voltage at the time of performing.

FIG. 3 is a plan view showing another structure of the one pixel.

FIG. 4 is a plan view showing one pixel of a conventional liquid crystal display device.

FIG. 5A is a plan view showing the structure of one pixel of the liquid crystal display device of the prior art publication, and FIG. 5B is a B view in FIG.
FIG. 6 is a cross-sectional view taken along the line B ′ of FIG.

FIG. 6 is an equivalent circuit diagram of the one pixel.

7A and 7B are waveform diagrams showing waveforms of data signals having the same polarity supplied to adjacent data signal lines in the one pixel, and FIG. 7C is a diagram showing the supply of the data signal. It is a waveform diagram which shows the waveform of the pixel voltage at the time of performing.

FIG. 8 is an equivalent circuit diagram of a pixel in consideration of off-resistance and source-drain capacitance of a thin film transistor.

FIG. 9A is a plan view showing a display screen of another conventional liquid crystal display device, and FIG. 9B is a plan view showing a display screen on which an image display corresponding to predetermined display data is performed. It is a figure.

FIG. 10 is a waveform chart showing fluctuations in average potential of data lines and charging potentials of pixels X and Y in the liquid crystal display device.

11 (a) and 11 (b) are waveform diagrams showing waveforms of data signals having opposite polarities supplied to the adjacent data signal lines in the one pixel, and FIG. It is a waveform diagram which shows the waveform of the pixel voltage at the time of performing.

[Explanation of symbols]

 1a data signal line (first signal line) 1b data signal line (first signal line) 2 scanning signal line (second signal line) 3 thin film transistor 7 second interlayer insulating film 8 pixel electrode

Claims (1)

[Claims] 1. A plurality of first signal lines, a plurality of second signal lines orthogonal to the first signal lines, and intersections between the first signal lines and the second signal lines. In a liquid crystal display device having a thin film transistor and a pixel electrode stacked on the adjacent first signal line via an insulating film, by supplying signals of opposite polarities to the adjacent first signal line. In order to compensate the pixel voltage decrease amount caused by the leak current of the thin film transistor by the pixel voltage fluctuation amount caused by the difference in the coupling capacitance between the first signal line and the pixel electrode, A liquid crystal display device, wherein the first signal line adjacent to the first signal line is overlapped with an insulating film.