JP3670517B2 - Liquid crystal display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device called a so-called lateral electric field method.
[0002]
[Prior art]
A liquid crystal display device referred to as a horizontal electric field method includes pixel electrodes disposed at a distance from each other in each pixel region on the liquid crystal side surface of one transparent substrate among the transparent substrates disposed to face each other via liquid crystal. An electric field is generated between the counter electrodes and the transmittance of light passing between the electrodes is controlled.
The counter electrodes in each pixel are commonly connected to each other so that a constant voltage is applied, and the pixel electrode in each pixel has a voltage applied to the counter electrode via a switching element as a reference voltage. A signal voltage corresponding to the gradation is applied.
[0003]
[Problems to be solved by the invention]
However, the liquid crystal display device having such a configuration is formed such that each pixel includes a plurality of pixel electrodes and counter electrodes, and a plurality of pairs of pixel electrodes and counter electrodes arranged to face each other. Yes.
[0004]
This is because such an arrangement has been unavoidable because it is necessary to reduce the distance between the pixel electrodes arranged opposite to each other and the counter electrode to a certain value or less.
This is because the maximum output voltage value of the driver that supplies the voltage signal to the pixel electrode and the counter electrode is restricted, but the maximum intensity of the electric field generated between these electrodes is secured to a certain value. is there.
[0005]
For this reason, the area occupied by the pixel electrode and the counter electrode is increased in each pixel, and the formation region of each electrode does not become a light transmission region.
[0006]
The present invention has been made based on such circumstances, and an object of the present invention is to provide a liquid crystal display device with an improved aperture ratio.
[0007]
[Means for Solving the Problems]
Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.
[0008]
That is, the liquid crystal display device according to the present invention basically includes a pixel electrode and a counter electrode that are arranged with a light transmission region of the liquid crystal in between, and applies a varying voltage to the counter electrode as well as this variation. A video signal is supplied to the pixel electrode using the voltage as a reference voltage.
[0009]
When configured in this way, the difference in voltage that can be applied between the pixel electrode and the counter electrode can be made substantially equal to the maximum level of the voltage that can be applied to the pixel electrode or the counter voltage, and can be made larger than in the prior art.
[0010]
This means that the distance between the pixel electrode and the counter electrode arranged in each pixel can be increased, and the occupied area per pixel can be reduced.
For this reason, the aperture ratio can be improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a liquid crystal display device according to the present invention will be described with reference to the drawings.
[Example 1]
Constitution
FIG. 1 is a block diagram showing an embodiment of a liquid crystal display device according to the present invention.
The figure shows one pixel (dotted line in the figure) of a liquid crystal side of one transparent substrate (referred to as a so-called TFT substrate) among a pair of transparent substrates arranged to face each other through the liquid crystal of a horizontal electric field type liquid crystal display device FIG. 5 is a plan view showing a portion surrounded by) and its vicinity region.
[0012]
In the figure, there is a transparent substrate 1, and a scanning signal line 2 extending in the x direction and arranged in parallel in the y direction is formed of, for example, a chromium layer on the surface of the transparent substrate 1.
An insulating film 3 made of, for example, a SiN film is formed over the entire surface of the transparent substrate 1 so as to cover the scanning signal line 2.
[0013]
This insulating film 3 functions as an interlayer insulating film for the scanning signal line 2 of the first signal line 5A and the second signal line 5B described later, and functions as a gate insulating film in a formation region of the thin film transistor TFT described later. A region for forming a storage capacitor element Cstg described later has a function as a dielectric film.
[0014]
Two thin film transistors TFT1 and TFT2 are formed on the scanning signal line 2 through the insulating film 3 in the region of one pixel. Each of the thin film transistors TFT1 and TFT2 has a part of the scanning signal line 2 as a gate electrode. In addition, the insulating film 3 is used as a gate insulating film.
[0015]
The thin film transistors TFT1 and TFT2 are positioned on the left side and the right side of the pixel, respectively, and semiconductor layers 4A and 4B made of, for example, a-Si are formed on the insulating film 3 at the positions, and the surfaces of the semiconductor layers 4A and 4B are further formed. In addition, a drain electrode and a source electrode are formed respectively, thereby forming an MIS type transistor having an inverted staggered structure.
[0016]
A part of each electrode of the thin film transistors TFT1 and TFT2 is formed together with the first signal line 5A (video signal line) and the second signal line 5B (counter voltage signal line), and the other part is the second. It is formed together with the electrode 6B (counter electrode).
[0017]
That is, the first signal line 5A (video signal line) extending in the y direction on the left side of the pixel region in the drawing is formed of, for example, a chrome layer, and a part of the first signal line 5A extends to the surface of the semiconductor layer 4A. The drain electrode is formed.
[0018]
Note that the source and drain are originally determined by the bias polarity, and in the circuit of this liquid crystal display device, the polarity is inverted during operation, so that the source and drain are interchanged during operation. However, in the following description, for convenience, one is fixed as a source and the other is fixed as a drain.
[0019]
Simultaneously with the formation of the first signal line 5A (video signal line), a source electrode 6S and a first electrode 6A (pixel electrode) extending from the source electrode 6S are formed on the semiconductor layer surface. It has become.
[0020]
The first electrode 6A (pixel electrode) is an electrode that generates an electric field in parallel with the transparent substrate 1 between a second electrode 6B (counter electrode) described later, and is adjacent to the first signal line 5A (video signal line). The extension end is bent so as to extend adjacent to the scanning signal line 2 and extend in parallel.
[0021]
The bent extended end of the first electrode 6A (pixel electrode) constitutes one electrode of a storage capacitor element Cstg described later.
[0022]
Simultaneously with the formation of the first signal line 5A (video signal line), the second signal line 5B (counter voltage signal line) extending in the y direction is formed on the right side of the pixel region in the drawing. The value of the line width of the second signal line 5B is not limited, but is preferably the same as the line width of the first signal line 5A.
[0023]
A part of the second signal line 5B (counter voltage signal line) is extended to the surface of the semiconductor layer 4B of the thin film transistor TFT2, thereby constituting the drain electrode of the thin film transistor TFT2.
[0024]
Further, the source electrode 6S 'is also formed when the drain electrode is formed. The source electrode 6S ′ in this case is connected to the second electrode 6B (counter electrode) as will be apparent from the following description, but the second electrode 6B (counter electrode) is layered. Since they are different, the electrode is formed as an electrode having a sufficient area for making contact with the second electrode 6B.
[0025]
The thin film transistors TFT1 and TFT2 are transistors that are simultaneously turned on when a scanning signal is supplied to the scanning signal line 2, and in this embodiment, both are n-channel MIS transistors. .
[0026]
That is, the semiconductor layers 4A and 4B of the thin film transistors TFT1 and TFT2 are exposed from the electrodes after the n-type impurity layer is formed by doping the surface thereof to form the n-type impurity layer and the drain electrode and the source electrode are formed. The n-type impurity layer is etched using each electrode as a mask, and the n-type impurity layer is formed as an ohmic layer only at the interface between each electrode and the semiconductor layer.
[0027]
The pattern of the thin film transistor TFT2 is not limited, but is preferably the same as the pattern of the thin film transistor TFT1.
That is, it is preferable that the channel widths and channel lengths of the thin film transistors TFT1 and TFT2, and the overlapping area of each electrode with the semiconductor layer are equal (meaning that the parasitic capacitances are equal).
[0028]
The reason for this is that the condition (resistance, capacitance) of the path of the signal applied from the first signal line 5A to the first electrode 6A via the thin film transistor TFT1 and the second condition from the second signal line 5B via the thin film transistor TFT2 This is because the condition of the path of the signal applied to the electrode 6B is made substantially equal, thereby making the influence of the waveform distortion of the signal almost the same.
[0029]
Further, on the surface of the transparent substrate 1 processed in this way, a protective film 7 made of, for example, a SiN film is formed over the entire region (at least in a display region that is an aggregate of each pixel).
[0030]
The protective film 7 has a function of avoiding direct contact of the film transistors TFT1 and TFT2 with the liquid crystal and preventing the characteristics from being deteriorated by the liquid crystal.
[0031]
In this case, the protective film 7 has a contact hole formed in a portion where the source electrode 6S 'of the thin film transistor TFT2 is formed.
That is, the source electrode 6S 'is connected to the second electrode 6B (counter electrode) formed on the protective film 7 through the contact hole.
[0032]
The second electrode 6B is formed of, for example, a chrome layer, and extends adjacent to and parallel to the second signal line 5B (counter voltage signal line). Thereafter, the extending end is adjacent to and parallel to the scanning signal line 2. It is bent so as to extend.
[0033]
Needless to say, the second electrode may be formed of an ITO (Indium-Tin-Oxide) film. In the horizontal electric field type liquid crystal display device, the ITO film is formed on the scanning signal line 2 or the signal supply terminal of the other signal line, so as to be overlapped with the terminal in order to avoid the electrolytic corrosion of the portion. Is normal. For this reason, when the ITO film is formed, the second electrode 6B is formed at the same time, so that an increase in the manufacturing process can be avoided.
[0034]
The bent extended end of the second electrode 6B (counter electrode) is formed so as to overlap the bent extended end of the first electrode 6A (pixel electrode) via the protective film 7, and the protective film 7 is formed. The other electrode of the storage capacitor element Cstg as a dielectric film is configured.
[0035]
The storage capacitor element Cstg has a function of, for example, holding the signal voltage stored up to that time when the thin film transistors TFT1 and TFT2 are turned off for a relatively long time.
[0036]
An alignment film (not shown) is formed over the entire surface of the transparent substrate thus processed (at least in the display area which is an aggregate of each pixel), and the liquid crystal directly contacting the alignment film is formed. The initial orientation direction can be determined.
The TFT substrate thus formed is assembled so as to be opposed to a so-called filter substrate via a liquid crystal.
[0037]
The filter substrate has a black matrix formed so as to define each pixel region, a color (red, green, blue) filter formed in the opening of the black matrix, and an alignment formed in contact with the liquid crystal. A film or the like is formed.
[0038]
A video signal is supplied from the first signal line 5A (video signal line) to the first electrode 6A (pixel electrode) via the thin film transistor TFT1, and a counter voltage signal is supplied from the second signal line 5B (counter voltage signal line). Is supplied to the second electrode 6B (counter electrode) via the thin film transistor TFT2.
[0039]
Thereby, an electric field is generated in parallel with the transparent substrate 1 between the first electrode 6A (pixel electrode) and the second electrode 6B (counter electrode), and the light transmittance of the liquid crystal is controlled according to the strength of the electric field. It is like that.
[0040]
Such a configuration is referred to as a so-called lateral electric field method, in which the first electrode and the second electrode are disposed with the light transmission region of the liquid crystal in between, or in other words, a direction substantially orthogonal to the light transmission direction of the liquid crystal. It has a feature in a configuration that generates an electric field.
[0041]
In the above-described embodiment, one first electrode 6A (pixel electrode) and one second electrode 6B (counter electrode) are provided in each pixel.
However, the present invention is not limited to this, and it is a matter of course that the number may be more than that, and they may be arranged in, for example, a comb shape.
[0042]
An object of the present invention is to improve the aperture ratio by reducing the area occupied by each electrode, but how large the distance between the electrodes is due to the maximum output voltage set by the driver used in the liquid crystal display device. This is because there is an original purpose in whether it can be done.
[0043]
In the embodiment described above, the first signal line 5A is a video signal line, the first electrode 6A is a pixel electrode, the second signal line 5B is a counter voltage signal line, and the second electrode 6B is a counter electrode. It is. However, the same applies when the second signal line 5B is a video signal line, the second electrode 6B is a pixel electrode, the first signal line 5A is a counter voltage signal line, and the first electrode 6A is a counter electrode. Needless to say.
[0044]
Drive form
FIG. 2 is a graph showing the relationship between the voltage signal applied to the pixel electrode of the liquid crystal display device (solid line D1) and the voltage signal applied to the counter voltage (dotted line D2). When the voltage between the pixel electrode and the counter electrode is high, FIG. 5B shows the case where the voltage between the pixel electrode and the counter electrode is low.
[0045]
In each figure, in order to prevent polarization of liquid crystal molecules, so-called AC driving is performed in which the high level side of the voltage applied to the pixel electrode and the counter electrode is sequentially switched.
[0046]
That is, for example, when the voltage between the pixel electrode and the counter electrode shown in (a) is high, the voltage signal applied to the pixel electrode becomes low level after it becomes high level (maximum output level) via the thin film transistor TFT1. (Minimum output level) can be switched.
[0047]
Further, in this case, the voltage signal applied to the counter electrode is switched to the high level (maximum output level) after having become the low level (minimum output level) via the thin film transistor TFT2.
[0048]
This is because the widths of the maximum output voltages of the drive circuit (driver) that supplies the voltage signal to the pixel electrode and the drive circuit (driver) that supplies the voltage signal to the counter electrode are V1 and V2 (V1 = V2). When the width of the maximum output voltage and the minimum output voltage of the driver is V2, a voltage of V (= V1 = V2) as the maximum value can be applied between the pixel electrode and the counter electrode.
[0049]
That is, the separation distance between the pixel electrode and the counter voltage can be increased to the extent that the light transmittance of the liquid crystal can be maximized in a state where a voltage of V is applied between the pixel electrode and the counter voltage. To do.
[0050]
In contrast, FIG. 3 is a diagram illustrating the relationship between the signal voltage (solid line D) applied to the pixel electrode of the conventional liquid crystal display device and the signal voltage (dotted line) applied to the counter voltage corresponding to FIG. Shown in
[0051]
The signal voltage applied to the counter electrode is constant (common potential), and a signal voltage that is inverted to the pixel electrode is applied using the constant signal voltage as a reference voltage.
[0052]
Therefore, the maximum output voltage and the minimum output voltage of the driver with respect to the positive and negative output voltages V1 and V2 (V1 = V2) based on the voltage of the counter electrode of the driver that supplies a voltage signal to the pixel electrode. Since V1 + V2 = V, only the voltage of V / 2 can be applied between the pixel electrode and the counter electrode as the maximum value.
[0053]
effect
As will be apparent from the driving mode described above, the voltage that can be applied between the pixel electrode and the counter electrode can be made larger than before, and thereby the distance between the pixel electrode and the counter electrode can be made larger than before. Will be able to.
[0054]
This means that the number of pixel electrodes and counter electrodes arranged in one pixel can be reduced.
For this reason, the area occupied by one pixel electrode and the counter electrode in one pixel can be reduced, and the aperture ratio can be improved.
[0055]
FIG. 4A is a graph showing the improvement of the aperture ratio of the liquid crystal display device according to the present invention compared with the conventional liquid crystal display device.
According to this graph, the horizontal axis indicates the pixel pitch (μm), and the vertical axis indicates the aperture ratio (%). It can be seen that the aperture ratio can be improved as compared with the conventional case when the pixel pitch is 258 μm or more. .
Here, as shown in FIG. 4B, the pixel pitch indicates the pitch of three adjacent pixels in charge of the three primary colors for color.
[0056]
Further, in order to obtain the above-mentioned graph, the width of the video signal line is 8 μm, the width of each of the scanning signal line and the counter voltage signal line is 30 μm, the separation rule of the signal lines of the same layer is 6 μm or more, and the signal lines of different layers Was set to 2 μm or more.
Further, the width of the pixel electrode and the counter electrode is set to 6 μm, and the distance between them is set to 30 μm at the maximum in the case of the present invention, and to 15 μm at the maximum in the conventional case.
[0057]
FIG. 5 is a graph showing that when the pixel pitch is set to 258 μm or more, the aperture ratio is improved accordingly.
In the figure, the characteristic indicated by a round dot is when the electrode width is constant, and the characteristic indicated by a solid line is when the electrode width is variable.
[0058]
Further, FIG. 6 is a graph showing pixel pitches (corresponding almost to the aperture ratio) in the diagonal size of the display unit according to resolutions VGA, SVGA, XGA, SXGA, and UXGA.
[0059]
From the graph, when the pixel pitch is 258 or more and the resolution is VGA, the diagonal size is 8.2 inches or more, when the resolution is SVGA, the diagonal size is 10.2 inches or more, and the resolution is XGA. The diagonal size is 13.0 inches or more when the resolution is SXGA, the diagonal size is 14.1 inches or more when the resolution is SXGA, and the diagonal size is 16.8 inches or more when the resolution is UXGA. It turns out that the aperture ratio can be improved.
[0060]
Further, according to the above drive mode, since the DC component is not included in the voltage between the pixel electrode and the counter electrode, the driver connected to the video signal line and the driver connected to the counter voltage signal line are By making them the same, afterimages, flickers and the like are less likely to occur.
[0061]
For this reason, even when the thin film transistor is turned off, the gate of the thin film transistor. There is an effect that there is little influence on the generation of the jump voltage due to the parasitic capacitance Cgs between the sources.
[0062]
On the other hand, in the conventional liquid crystal display device, the center of the video signal is shifted with respect to the common potential with respect to the generation of the jump voltage due to the parasitic capacitance Cgs of the thin film transistor when the thin film transistor is turned off (shown as Vx in FIG. 7). ), An afterimage or flicker is likely to occur due to the DC component at that time.
[0063]
[Example 2]
FIG. 8 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention and corresponds to FIG.
1 is different from the case of FIG. 1 in that the first electrode 6A (pixel electrode) is formed in advance simultaneously with the formation of the scanning signal line 2 (and therefore the same material).
[0064]
Then, after the insulating film 3 is formed, it is formed between the source electrode of the thin film transistor TFT1 and the first electrode 6A simultaneously with the formation of the second electrode 6B (counter electrode) extending from the source electrode of the thin film transistor TFT2. Connection can be achieved by the conductive layer 10 (same material as the counter electrode).
[0065]
In this case, the conductive layer 10 is an ITO film formed at the same time as the ITO film formed to overlap with the signal supply terminals of the scanning signal line 2 or other signal lines in order to prevent electrolytic corrosion. An increase can be avoided.
[0066]
For this reason, the insulating film 3 is formed with a contact hole for exposing a part of the source electrode of the thin film transistor TFT1, and an accumulation formed between the first electrode 6A and the second electrode 6B. It becomes a dielectric film of the capacitive element Cstg.
[0067]
Example 3
FIG. 9 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention and corresponds to FIG.
In the figure, the first electrode 6A (pixel electrode) is formed at the same time as the scanning signal line 2 and is connected to the source electrode of the thin film transistor TFT1 through the insulating film 3 as in the case of FIG.
[0068]
However, the second electrode is different from FIG. 8 in that the second electrode is formed on the protective film 7 and connected to the source electrode 6S ′ of the thin film transistor TFT2 through a contact hole formed in the protective film 7.
[0069]
The source electrode 6S 'is formed simultaneously with the source electrode 6S of the thin film transistor TFT1, and the material thereof is made of, for example, an ITO film.
In this case, the dielectric film of the storage capacitor element Cstg is a laminate of the insulating film 3 and the protective film 7.
[0070]
Example 4
FIG. 10 shows an embodiment in which a voltage signal is supplied to each of the first signal line 5A (video signal line) and the second signal line 5B (counter voltage signal line) in the liquid crystal display device having the pixel configuration described above. It is a thing.
[0071]
In the figure, a scanning signal driving circuit 11 is connected to one end side of each scanning signal line 2, and a video signal driving circuit 12 is connected to one end side of each first signal line 5A and second signal line 5B. .
[0072]
Each of the drive circuits 11 and 12 is controlled by a controller 13 to which image information is input. The scan signal drive circuit 11 sequentially supplies a scan signal to each scan signal line 2 and matches the timing. From the video signal driving circuit 12, a video signal and a counter voltage signal are supplied to the first signal line 5A and the second signal line 5B, respectively.
[0073]
In each pixel, the counter voltage signal supplied to the second signal line 5B is a dot-inverted signal with respect to the video signal supplied to the first signal line 5A, and has the same gradation every two lines. Data is supplied from the controller.
[0074]
Example 5
FIG. 11 shows an embodiment in which voltage signals are supplied to the video signal line and the counter voltage signal line in the liquid crystal display device having the above-described pixel configuration, and corresponds to FIG. .
[0075]
The difference from FIG. 10 is that the video signal driving circuit 12A for supplying the video signal to the first signal line 5A is connected to one end side of each first signal line 5A, whereas the video signal driving circuit 12A is connected to the second signal line 5B. The video signal drive circuit 12B that supplies the counter voltage signal is connected to the other end of the second signal line 5B.
[0076]
In this case, the respective pitches of the first signal line 5A and the second signal line 5B can be made constant when viewed from the drive circuits 12A and 12B, and the unbalance of the input signals in the lead-out wiring section can be reduced. The effect which can be prevented can be produced.
[0077]
Example 6
FIG. 12 shows another embodiment in which voltage signals are supplied to the video signal line and the counter voltage signal line in the liquid crystal display device having the above-described pixel configuration, and corresponds to FIG. ing.
[0078]
The counter voltage signal supplied to the second signal line 5B is the same as the case of FIG. 10 with respect to the video signal supplied to the first signal line 5A being a dot-inverted signal. The video signal supplied to the first signal line 5A on the pixel side adjacent thereto is driven so as to have the same polarity as the counter voltage signal.
[0079]
That is, the first signal line, the second signal line arranged with a substantial pixel area between the first signal line, the first signal line arranged close to the second signal line, the first signal line The counter signal is supplied to the second signal line and the first signal line, which are arranged close to each other, in the arrangement relationship of the second signal line arranged with the signal line and the substantial pixel region in between. The signal and the video voltage signal are driven so as to avoid the dot-inverted relationship with each other and to have the same polarity.
In such a case, the adjacent second signal line 5B and the first signal line 5A have an effect of reducing the adverse effect of one signal on the other signal.
[0080]
Example 7
FIG. 13 shows another embodiment in which voltage signals are supplied to the video signal line and the counter voltage signal line in the liquid crystal display device having the above-described pixel configuration, and corresponds to FIG. ing.
[0081]
11 is different from the case of FIG. 11 in that the same polarity signal is supplied to the adjacent first signal line 5A and the second signal line 5B, as in the above-described embodiment, so that the signal of one signal line is different. The adverse effect on the signal of the other signal line can be reduced.
[0082]
【The invention's effect】
As is clear from the above description, the liquid crystal display device according to the present invention can improve the aperture ratio.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating one embodiment of a pixel of a liquid crystal display device according to the present invention.
FIG. 2 is an explanatory diagram showing voltage signals applied to pixels of the liquid crystal display device shown in FIG.
FIG. 3 is an explanatory diagram showing a voltage signal applied to a pixel of a conventional liquid crystal display device.
FIG. 4 is a graph showing an improvement in the aperture ratio of the liquid crystal display device according to the present invention.
FIG. 5 is a graph showing an improvement in aperture ratio of the liquid crystal display device according to the present invention as compared with the conventional case.
FIG. 6 is a graph showing the improvement of the aperture ratio according to the resolution of the liquid crystal display device according to the present invention.
FIG. 7 is an explanatory diagram for comparing the effect of the liquid crystal display device according to the present invention with the conventional case.
FIG. 8 is a block diagram showing another embodiment of the pixel of the liquid crystal display device according to the present invention.
FIG. 9 is a block diagram showing another embodiment of the pixel of the liquid crystal display device according to the present invention.
FIG. 10 is a configuration diagram showing one embodiment of a signal line of a liquid crystal display device according to the present invention and a drive circuit connected to the signal line.
FIG. 11 is a configuration diagram showing another embodiment of a signal line of a liquid crystal display device according to the present invention and a drive circuit connected to the signal line.
FIG. 12 is a configuration diagram showing another embodiment of a signal line of a liquid crystal display device according to the present invention and a driving circuit connected thereto.
FIG. 13 is a configuration diagram showing another embodiment of a signal line of a liquid crystal display device according to the present invention and a driving circuit connected to the signal line.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Transparent substrate, 2 ... Scanning signal line, 3 ... Insulating film, 4A, 4B ... Semiconductor layer, 5A ... 1st signal line, 5B ... 2nd signal line, 6A ... 1st electrode, 6B: second electrode, 7: protective film, TFT: thin film transistor, Cstg: storage capacitor element.

Claims (6)

Of the first and second substrates opposed to each other through the liquid crystal, the first substrate has a scanning signal line, a first signal line, and a second signal line,
Each pixel includes a first thin film transistor and the second thin film transistor which is controlled by the same scan signal line, a first electrode to which a signal is supplied from the first signal line by said first thin film transistor, the first A second electrode to which a signal is supplied from the second signal line by two thin film transistors,
The signals supplied to the first signal line and the second signal line are signals whose polarities are inverted at the same gradation.
The liquid crystal display device, wherein the first electrode and the second electrode form a storage capacitor, and an electric field for controlling light transmittance is formed between the first electrode and the second electrode. 2. The liquid crystal display device according to claim 1 , wherein the liquid crystal display device is driven so that the high level sides of the first electrode and the second electrode are sequentially switched. The liquid crystal display device according to claim 1 or claim 2 wherein the dot inversion signal to the first signal line and the second signal line, characterized in that the supplied. The liquid crystal display device according to any one of claims 1 to 3, wherein the first thin film transistor and the second thin film transistor are substantially the same pattern. The liquid crystal display device according to claim 4 , wherein the first thin film transistor and the second thin film transistor have substantially the same channel width and channel length. 5. The liquid crystal display device according to claim 4 , wherein an overlapping area of the first electrode with the semiconductor layer is substantially equal to an overlapping area of the second electrode with the semiconductor layer.

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