JP4680233B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device, and more particularly to a so-called vertical alignment method.

The liquid crystal display device is configured to control light transmittance by an electric field generated between a pair of electrodes with respect to the liquid crystal in the pixel region.
Such a liquid crystal display device includes an alignment film disposed so as to be in direct contact with the liquid crystal in order to determine the initial alignment direction of the liquid crystal when the electric field is not applied.
Conventionally, the alignment film has required an alignment process by rubbing, but a so-called vertical alignment method has been developed as a liquid crystal mode in which the rubbing process is unnecessary and the process can be omitted (for example, JP-A-11-72793, JP-A-11-109355, JP-A-11-352489).
That is, by using a so-called vertical alignment film, the liquid crystal molecules are aligned in the vertical direction with respect to the substrate in the absence of an electric field without a rubbing treatment, and the liquid crystal molecules are tilted in a plurality of directions when an electric field is applied.
And, when the liquid crystal molecules are tilted in a plurality of directions, a wide viewing angle as a liquid crystal display characteristic is achieved at the same time.
Japanese Patent Laid-Open No. 11-72793 JP-A-11-109355 Japanese Patent Laid-Open No. 11-352489

However, in the liquid crystal display device having such a configuration, as a result of further investigation by the applicants, as shown in FIG. 22, when external pressure is applied to the liquid crystal display panel LPNL, for example, the liquid crystal display It has been found that when the part AR is lightly pressed with a finger, the mark pressed on the part may remain for a long time of about several tens of minutes (the mark thus remaining is referred to in this specification for the sake of convenience). This is called “stain display”).
Pushing the liquid crystal display panel LPNL in this way often occurs, for example, when discussing while viewing the display of the liquid crystal display panel LPNL by a plurality of people or when wiping the liquid crystal display portion AR of the liquid crystal display panel LPNL. The fact that the trace remains as described above is a big problem in actual use. This is because the remaining part of the mark cannot be displayed normally as a display.

  As shown in each operation of FIGS. 22A, 22B, and 22C, the occurrence situation is severe, and a trace that is pressed with a finger remains as it is. For example, if the finger is moved while moving to the shape of a character or figure, It remained for a long time. 22A shows a state before the display surface of the liquid crystal display panel is pressed, FIG. 22B shows a state where the finger is moved while pressing, and FIG. 22C shows a state after being left unattended. .

The reason why such a phenomenon occurs will be described focusing on the behavior of the liquid crystal. First, as shown in FIG. 23, the electric field E generated between a pair of electrodes PX and CT provided on each substrate side, respectively. By giving directionality to a part of the regions (center in the figure), the liquid crystal molecules fall in a plurality of directions.
When the electric field E is increased as shown in FIGS. 23 (a) to 23 (c) (the voltage applied to the pair of electrodes is changed from small to medium to large), the liquid crystal molecules are in the central portion. The liquid crystal molecules on the outside fall down in the same direction with reference to the direction in which the central part falls.

Furthermore, as shown in FIGS. 24 (a) to 24 (c), when one of the substrates is pushed in this state (FIG. 24 (a)) (FIG. 24 (b)), the substrate SUB1 The distance between the substrate SUB2 is reduced (d2 <d1), and thereby the distance between the pixel electrode PX and the counter electrode CT is reduced.
This means that the intensity of the electric field E between the pixel electrode PX and the counter electrode CT is increased, and an electric field stronger than the display electric field corresponding to the original gradation is applied to the liquid crystal molecules while being pressed against each other. .
As a result, it is found that an intermediate layer MIDL composed of liquid crystal molecules arranged almost horizontally is formed near the center of the liquid crystal layer between the substrates.

In this intermediate layer MIDL, since the liquid crystal molecules are substantially horizontal to each other, the major axis directions of the liquid crystal molecules are arranged in parallel, and a strong intermolecular force acts on each other. For this reason, it is found that the intermediate layer MIDL is in a metastable state, the state is fixed, and exhibits a memory effect.
When the pressing force is lost, the distance between the substrates returns to d1 (FIG. 24C). At this time, the liquid crystal molecules in the vicinity of the vertical alignment films AL1 and AL2 return to the original tilted state given by the electric field E.
However, even if this is the case, it is found that the liquid crystal molecules of the intermediate layer MIDL still maintain a substantially horizontal state.

This was found to be due to the following reason. That is, the alignment effect of the liquid crystal molecules by the vertical alignment films AL1 and AL2 extends only to the liquid crystal molecules in contact with the alignment film, and the alignment state of the other liquid crystal molecules is between the pixel electrode PX and the counter electrode CT. It is determined by the electric field and intermolecular force between liquid crystal molecules.
That is, the liquid crystal molecules other than the interface are tilted in the horizontal direction or the horizontal direction by the electric field E, and return to the vertical direction or the vertical direction by the intermolecular force between the liquid crystal molecules. For this reason, the degree of inclination of the liquid crystal molecules other than the interface is determined by the balance between the electric field E and the intermolecular force between the liquid crystal molecules.

Here, there is no pushing force as described above, and in the normal case, the liquid crystal molecules are tilted by the electric field, but as shown in FIG. Tilt. Therefore, the intermolecular force is in a state of strongly acting between molecules in the longitudinal direction of the liquid crystal layer.
For this reason, if the electric field is reduced, the slope returns to the slope corresponding to the intensity of the electric field E after the whole has been reduced substantially uniformly. When the electric field is minimized, the liquid crystal molecules in the vicinity of the vertical alignment films AL1 and AL2 gradually return to vertical by the action of the vertical alignment films AL1 and AL2.
At this time, due to the intermolecular force between the liquid crystal molecules, the liquid crystal molecules other than the interface gradually return to vertical according to the return amount of the liquid crystal molecules at the interface, and return to the vertical state as a whole.

From this, the above contents will be briefly described. When an applied pressure is applied to the liquid crystal display panel as shown in FIG. 24B, an intermediate layer in which the liquid crystal molecules are arranged substantially horizontally in the major axis direction. Even if the MIDL is formed and the pressurization is lost, the intermediate layer MIDL forms a metastable state in which intermolecular force acts on each other, so that the state is maintained when a certain electric field is applied. Become.
The liquid crystal molecules in the vicinity of the interface return to the normal alignment direction by the action of the vertical alignment films AL1 and AL2.

Normally, liquid crystal molecules other than the alignment film interface should return to the original accordingly. However, the intermolecular force applied to the liquid crystal molecules on the interface side of the intermediate layer due to the formation of the intermediate layer MIDL is expressed by the following formula ( 1)
[Equation 1] (Intermolecular force received from liquid crystal molecules at the alignment film interface) <(Intermolecular force received from the entire liquid crystal molecules in the intermediate layer) + (Alignment force in the horizontal direction of the liquid crystal due to an electric field) (1)
Will satisfy the relationship.
Since the entire liquid crystal molecules of the intermediate layer MIDL are in a substantially horizontal state, as a result, the liquid crystal molecules on the interface side of the intermediate layer MIDL also maintain the horizontal state.

In this way, once the intermediate layer is formed, a term of intermolecular force received from the entire liquid crystal molecules of the intermediate layer MIDL is generated, so that it is maintained metastable for a long time. As a result, the memory property is exhibited, and a state in which a picture can be drawn with a finger occurs as described in the problem.
Such a phenomenon has not been found in any of the conventional liquid crystal display panels of the TN mode, STN mode, and horizontal electric field mode.

The reason for this is as follows.
First, in the TN mode and STN mode, liquid crystal molecules use a large amount of a material that imparts twist to a liquid crystal layer called a chiral material. Thereby, the intermolecular force between adjacent liquid crystal molecules is extremely strong. As a result, even if a state corresponding to the intermediate layer occurs, for example, the intermediate layer is eliminated by the effect of the large amount of chiral material.

Further, the liquid crystal molecules in the vicinity of the alignment film interface are in a horizontal state with a tilt angle of about several to tens of degrees, and when a voltage is applied, the liquid crystal molecules gradually become vertical toward the intermediate portion of the liquid crystal layer.
Therefore, even if the substrate is pushed, the liquid crystal molecules in the intermediate portion are in a sleeping direction, so that the interaction with the vicinity of the interface of the alignment film is increased. In principle, the intermediate layer is hardly formed.

Further, in the lateral electric field method, liquid crystal molecules are arranged almost in parallel, so that the intermolecular force between the liquid crystal molecules is structurally strong. And since it is originally horizontal, the horizontal state is only maintained even if the substrate is pressed, and it is difficult to form the intermediate layer.
Therefore, it becomes clear that this phenomenon is a peculiar phenomenon in the vertical alignment method. Therefore, in the conventional liquid crystal display device, disclosure and countermeasures regarding the phenomenon are not made.

Furthermore, as a result of the elucidation of the phenomenon by the present inventors, the following phenomenon has been found.
That is, it was found that this phenomenon depends on the voltage. For example, in the case of normally black (black when the voltage is low, white when the voltage is high), it has been found that this phenomenon occurs particularly prominently when the liquid crystal display panel LPNL is pressed when the voltage is 30% to 100%.
Here, for the sake of explanation, a case of normally black (low voltage is black, high voltage is white) will be described as an example. In the case of normally white, it only reverses.

25A to 25C are diagrams showing the behavior of liquid crystal molecules when the applied voltage is 0% to 30%. 25A shows a state before pressing, FIG. 25B shows a pressing state, and FIG. 25C shows a state after pressing.
In this state, the voltage is small, and the liquid crystal molecules are almost vertical. The liquid crystal molecules in the middle part of the liquid crystal layer are also almost perpendicular, and the major axes of the liquid crystal molecules are perpendicular to each other.

And
1) Liquid crystal molecules at the interface between the vertical alignment films AL1 and AL2 receive strong interaction from the vertical alignment films AL1 and AL2, and maintain a vertical state.
2) Liquid crystal molecules are aligned in the vertical direction, and an intermolecular force that maintains the vertical direction works.
3) The strength of the electric field formed between the upper and lower substrates is low, and even when the substrate is pushed, there is no force to move the liquid crystal molecules from the vertical state to the horizontal state.
For this reason, the intermediate layer does not occur, and it returns to the original state after being pushed.

FIGS. 26A to 26C are diagrams showing the behavior of liquid crystal molecules when the applied voltage is 70% to 100%. Also in this case, FIG. 26A shows a state before pressing, FIG. 26B shows a pressing state, and FIG. 26C shows a state after pressing.
In this state, the voltage and the liquid crystal molecules are almost horizontal. When the surface of the liquid crystal display panel is pressed, the distance between the substrates decreases and the electric field strength increases. Originally, the liquid crystal molecules are almost in a horizontal state, so that the liquid crystal molecules are almost horizontal in the middle portion of the liquid crystal layer due to an increase in the electric field due to the distance reduction between the substrates due to the pressing of the substrates. As a result, an intermediate layer is formed, and memory performance is exhibited.

FIGS. 27A to 27C are diagrams showing the behavior of liquid crystal molecules when the applied voltage is 30% to 70%. Also in this case, FIG. 27A shows a state before pressing, FIG. 27B shows a pressing state, and FIG. 27C shows a state after pressing.
In this state, the voltage is intermediate, and the liquid crystal molecules are in an intermediate state from vertical to horizontal. When the surface of the liquid crystal display panel is pressed, the distance between the substrates is reduced and the electric field strength is increased.
Then, the liquid crystal molecules in the intermediate portion are aligned substantially horizontally, and the intermediate layer MIDL is formed as described above.

  On the other hand, the liquid crystal molecules near the interface between the vertical alignment films AL1 and AL2 are not horizontal due to the effect of the vertical alignment films AL1 and AL2. For this reason, since the liquid crystal molecules in the intermediate layer and the liquid crystal molecules at the interface are different in the direction in which the long axes are aligned, the intermolecular force between the liquid crystal molecules in the two regions becomes weak. Therefore, the intermediate layer is maintained even after the pressure is removed, and the memory property is generated.

The present invention has been made based on such circumstances, and an object thereof is to provide a liquid crystal display device that avoids the above-described stain display.
Another object of the present invention is to provide a liquid crystal display device that effectively utilizes the above-described stain display.

As a result of the above discovery and research by the inventors, the following solution method has been invented.
That is, in brief, in a liquid crystal display device oriented in the vertical direction, a voltage of 20% or less of the maximum voltage is applied to all the pixels at once or in sequence every predetermined time.

As shown in the above formula (1), the development of the memory property of the liquid crystal display panel is the generation of the intermolecular force of the liquid crystal intermediate layer MIDL. However, since this intermolecular force is due to the intermolecular force, its strength is a limited value. For this reason, by reducing the term of the orientation force due to the electric field of the second term on the right side of the above formula, the left side> the right side can be set in Formula (1).
As a result, the formation of the intermediate layer MIDL becomes energetically unstable, so that the intermediate layer MIDL is eliminated, and the liquid crystal molecules return to a normal alignment state determined by the vertical alignment film and the electric field.
At this time, it seems to be sufficient to apply a voltage of 30% or less of the maximum voltage at first glance. However, since the state of the intermediate layer MIDL exists as a metastable state, 20% or less of the maximum voltage is required to cancel this metastable state. It has been found desirable to reduce the voltage at which the electric field is formed.

Then, due to the electric field reduction, the liquid crystal molecules in the vicinity of the interface of the intermediate layer MIDL approach the state of being aligned in parallel with the liquid crystal molecules in the vicinity of the vertical alignment film, and the intermolecular force of the liquid crystal molecules with the intermediate layer MIDL increases.
As a result, first, the intermolecular force applied to the liquid crystal molecules outside the intermediate layer MIDL is (intermolecular force with the liquid crystal molecules at the alignment layer interface)> (intermolecular force from the liquid crystal molecules in the intermediate layer). The outer liquid crystal molecules are arranged almost in parallel with the liquid crystal molecules at the alignment film interface.
Thereafter, the liquid crystal molecules sequentially spread to the next liquid crystal molecules in the intermediate layer, and eventually the whole is restored to a normal alignment state.

More desirably, it is desirable to completely eliminate the ability to maintain the intermediate layer MIDL by the electric field. For this purpose, it is more desirable to apply the minimum electric field, that is, the minimum voltage. With this minimum voltage application, the display can be instantaneously restored.
For these reasons, the outline of typical ones of the inventions disclosed in the present application will be briefly described as follows.

Means 1.
The liquid crystal display device according to the present invention includes, for example, a first substrate and a second substrate that are arranged to face each other via a liquid crystal,
A first electrode formed in a pixel region on a liquid crystal side surface of the first substrate; and a second electrode formed in a pixel region on a liquid crystal side surface of the second substrate;
Between the first electrode and the second electrode, liquid crystal molecules are arranged in a direction substantially perpendicular to the substrate in a state where no electric field is generated,
It has means for intermittently applying a voltage of 20% or less of the maximum voltage to the voltage applied between the first electrode and the second electrode.

Mean 2.
The liquid crystal display device according to the present invention is applied, for example, between the first electrode and the second electrode in the whole or a part of the liquid crystal display unit composed of a set of pixel regions on the assumption of the configuration of the means 1. A voltage of 20% or less of the maximum voltage is intermittently applied.

Means 3.
The liquid crystal display device according to the present invention is based on, for example, the configuration of the means 1, and the application of a voltage of 20% or less of the maximum voltage applied between the first electrode and the second electrode is 5 per second. It is characterized by being made at a rate of less than the number of times.

Means 4.
The liquid crystal display device according to the present invention includes, for example, a first substrate and a second substrate that are arranged to face each other via a liquid crystal,
A first electrode formed in a pixel region on a liquid crystal side surface of the first substrate; and a second electrode formed in a pixel region on a liquid crystal side surface of the second substrate;
Between the first electrode and the second electrode, liquid crystal molecules are arranged in a direction substantially perpendicular to the substrate in a state where no electric field is generated,
With respect to the voltage applied between the first electrode and the second electrode, a voltage equal to or less than 20% of the maximum voltage is applied to one pixel area per minute in at least a part of the pixel area aggregate. It has a means to apply more than once.

Means 5.
The liquid crystal display device according to the present invention includes, for example, a first substrate and a second substrate that are arranged to face each other via a liquid crystal,
A first electrode formed in a pixel region on a liquid crystal side surface of the first substrate; and a second electrode formed in a pixel region on a liquid crystal side surface of the second substrate;
Between the first electrode and the second electrode, liquid crystal molecules are arranged in a direction perpendicular to the substrate in a state where no electric field is generated,
With respect to the voltage applied between the first electrode and the second electrode, a voltage equal to or less than 20% of the maximum voltage is set to 1 in 5 seconds in at least a part of the pixel regions of the aggregate of the pixel regions. It has a means to apply more than once.

Means 6.
The liquid crystal display device according to the present invention is premised on the configuration of the means 1, for example, and the pixels are arranged in a matrix, and are arranged in parallel in a direction intersecting the one direction from a group of pixels arranged in parallel on one line. Each pixel is driven in order to reach another pixel group, and a voltage of 20% or less of the maximum voltage applied between the first electrode and the second electrode is applied to one or more lines. It is characterized by being sequentially performed in units.

Mean 7
The liquid crystal display device according to the present invention includes, for example, a first substrate and a second substrate that are arranged to face each other via a liquid crystal,
A first electrode formed in each pixel area on the liquid crystal display surface of the liquid crystal display section of the first substrate, and a pixel area on the liquid crystal side surface of the liquid crystal display section on the second substrate. A second electrode,
Between the first electrode and the second electrode, liquid crystal molecules are arranged in a direction substantially perpendicular to the substrate in a state where no electric field is generated,
Between the first electrode and the second electrode in each pixel region of each region of the liquid crystal display section divided into a plurality of regions, the first electrode and the first electrode are provided in units of one or more frames. And a means for sequentially applying a voltage of 20% or less of the maximum voltage to the voltage applied between the two electrodes.

Means 8.
The liquid crystal display device according to the present invention, for example, is based on the configuration of the means 7, and sequentially applies a voltage of 20% or less of the maximum voltage with respect to the voltage applied between the first electrode and the second electrode. Is made within one minute.

Means 9.
The liquid crystal display device according to the present invention, for example, is based on the configuration of the means 7, and sequentially applies a voltage of 20% or less of the maximum voltage with respect to the voltage applied between the first electrode and the second electrode. Is performed within 5 seconds.

Means 10.
The liquid crystal display device according to the present invention includes, for example, a first substrate and a second substrate that are arranged to face each other via a liquid crystal,
A liquid crystal display comprising: a first electrode formed in a pixel region on a liquid crystal side surface of the first substrate; and a second electrode formed in a pixel region on a liquid crystal side surface of the second substrate. A panel,
It consists of a touch panel arranged on the observation side surface of this liquid crystal display panel,
Means for applying a voltage of 20% or less of the maximum voltage with respect to a voltage applied between the first electrode and the second electrode of the pixel corresponding to the touched portion of the touch panel. It is characterized by.

Means 11.
The liquid crystal display device according to the present invention is based on, for example, the configuration of the means 10, and at least with respect to a voltage applied between the first electrode and the second electrode of the pixel corresponding to the touched portion of the touch panel. In addition, the application of a voltage that is 20% or less of the maximum voltage is performed after a lapse of 0.1 seconds or more after the touch is detected.

Means 12.
The liquid crystal display device according to the present invention is based on, for example, any one of the means 10 and 11, and the liquid crystal display panel is in a state where no electric field is generated between the first electrode and the second electrode. The liquid crystal molecules are arranged in a direction substantially perpendicular to the substrate.

Means 13.
The liquid crystal display device according to the present invention includes, for example, a first substrate and a second substrate that are arranged to face each other via a liquid crystal,
A liquid crystal display comprising: a first electrode formed in a pixel region on a liquid crystal side surface of the first substrate; and a second electrode formed in a pixel region on a liquid crystal side surface of the second substrate. A panel,
A liquid crystal display panel in which liquid crystal molecules are arranged in a direction substantially perpendicular to the substrate in a state where no electric field is generated between the first electrode and the second electrode;
A touch panel disposed on the viewing side of the liquid crystal display panel,
And a means for supplying a voltage signal that is 20% or less of the maximum voltage to a voltage applied between the first pixel electrode and the second electrode by touch detection by the touch panel. To do.

Means 14.
The liquid crystal display device according to the present invention is based on, for example, the configuration of the means 13 and turns off the path of the video signal supplied to the first pixel electrode, and between the first pixel electrode and the second electrode. A voltage signal that is 20% or less of the maximum voltage with respect to the voltage applied to the pixel is supplied by pixels corresponding to the touch location and its vicinity according to position information from the touch panel. is there.

Means 15.
The liquid crystal display device according to the present invention is based on, for example, the configuration of the means 13 and turns off the path of the video signal supplied to the first pixel electrode, and between the first pixel electrode and the second electrode. Supply of a voltage signal that is 20% or less of the maximum voltage with respect to the voltage applied to is performed at a pixel corresponding to the touch location according to position information from the touch panel.

Means 16.
The liquid crystal display device according to the present invention is characterized in that, for example, any one of the means 1 to 9 is assumed and a touch panel is provided on the observation side.

Means 17.
The liquid crystal display device according to the present invention is based on, for example, any one of the means 1 to 15, and is 20% of the maximum voltage with respect to the voltage applied between the first pixel electrode and the second electrode. The following voltage is a minimum voltage.

Means 18.
The liquid crystal display device according to the present invention assumes, for example, any one of the means 1 to 15, and displays black when an electric field is not generated between the first pixel electrode and the second electrode. It is characterized by a normally black mode.

Means 19.
The liquid crystal display device according to the present invention assumes, for example, the configuration of any one of means 1 to 15, and displays white when an electric field is not generated between the first pixel electrode and the second electrode. It is characterized by a normally white mode.

Means 20.
The liquid crystal display device according to the present invention assumes, for example, any one of the means 1 to 16, and displays black when an electric field is not generated between the first pixel electrode and the second electrode. It is characterized by a normally black mode.

Means 21.
The liquid crystal display device according to the present invention assumes, for example, any one of the means 1 to 16, and displays white when an electric field is not generated between the first pixel electrode and the second electrode. It is characterized by a normally white mode.

Means 22.
The liquid crystal display device according to the present invention assumes, for example, any one of the means 1 to 15, and displays black when an electric field is not generated between the first pixel electrode and the second electrode. It is a normally black mode, and a voltage that is 20% or less of the maximum voltage with respect to the voltage applied between the first pixel electrode and the second electrode is a black gradation signal. To do.

Means 23.
The liquid crystal display device according to the present invention assumes, for example, the configuration of any one of means 1 to 15, and displays white when an electric field is not generated between the first pixel electrode and the second electrode. It is a normally white mode, and a voltage that is 20% or less of the maximum voltage with respect to the voltage applied between the first pixel electrode and the second electrode is a white gradation signal. To do.

Means 24.
The liquid crystal display device according to the present invention is, for example, a normally black mode in which black display is performed when no electric field is generated between the first pixel electrode and the second electrode based on the configuration of the means 16. A voltage that is 20% or less of the maximum voltage with respect to the voltage applied between the first pixel electrode and the second electrode is a black gradation signal.

Means 25.
The liquid crystal display device according to the present invention is, for example, a normally white mode in which white display is performed when an electric field is not generated between the first pixel electrode and the second electrode on the premise of the configuration of the means 16. A voltage that is 20% or less of the maximum voltage with respect to the voltage applied between the first pixel electrode and the second electrode is a white gradation signal.
In addition, this invention is not limited to the above structure, A various change is possible in the range which does not deviate from the technical idea of this invention.

  As is apparent from the above description, according to the liquid crystal display device of the present invention, the above-described stain display can be avoided. In addition, the above-described stain display can be effectively utilized.

Hereinafter, embodiments of a liquid crystal display device according to the present invention will be described with reference to the drawings.
Example 1.
<< Overall structure >>
FIG. 1A is a schematic overall configuration diagram showing an embodiment of a liquid crystal display device according to the present invention.
In FIG. 1 (a), there is a pair of transparent substrates SUB1 and SUB2 arranged to face each other via a liquid crystal, and the liquid crystal is a sealing material (not shown) that also serves to fix the other transparent substrate SUB2 to one transparent substrate SUB1. ) Is enclosed.
On the liquid crystal side surface of the one transparent substrate SUB1 surrounded by the sealing material, the gate signal lines GL extending in the x direction and juxtaposed in the y direction extend in the y direction and juxtaposed in the x direction. The drain signal line DL is formed.
A region surrounded by each gate signal line GL and each drain signal line DL constitutes a pixel region, and a matrix aggregate of these pixel regions constitutes a liquid crystal display unit AR.

In each pixel region, as shown in FIG. 1B, a thin film transistor TFT that is operated by a scanning signal from the gate signal line GL on one side, and an image from the drain signal line DL on one side through the thin film transistor TFT. A pixel electrode PX to which a signal is supplied is formed.
This pixel electrode PX generates an electric field between a counter electrode (not shown) formed in common in each pixel region on the liquid crystal side surface of the other transparent substrate SUB2, and this electric field reduces the light transmittance of the liquid crystal. It is supposed to be controlled.
The pixel electrode PX forms a capacitive element Cadd between another adjacent gate signal line GL different from the gate signal line GL for driving the thin film transistor TFT. The capacitive element Cadd is provided for accumulating the signal for a relatively long time when a video signal is supplied to the pixel electrode PX.

One end of each of the gate signal lines GL extends beyond the sealing material, and the extending end constitutes a terminal to which the output terminal of the vertical scanning drive circuit V is connected. The input terminal of the vertical scanning drive circuit V receives a signal from a printed circuit board arranged outside the liquid crystal display panel, for example.
The vertical scanning drive circuit V is composed of, for example, a plurality of semiconductor devices, and a plurality of gate signal lines GL adjacent to each other are grouped, and one semiconductor device is assigned to each group.

Similarly, one end of each drain signal line DL extends beyond the sealing material SL, and the extending end constitutes a terminal to which the output terminal of the video signal driving circuit He is connected. . The input terminal of the video signal driving circuit He is adapted to receive a signal from a printed circuit board arranged outside the liquid crystal display panel.
The video signal drive circuit He is also composed of a plurality of semiconductor devices, for example, and a plurality of drain signal lines DL adjacent to each other are grouped, and one semiconductor device is assigned to each group.
The counter voltage signal line CL is commonly connected at the right end in the figure, and the connection line extends beyond the sealing material, and constitutes a terminal at the extended end. A voltage serving as a reference for the video signal is supplied from this terminal.

The scanning signal drive circuit V and the video signal drive circuit He are supplied with power and control signals from the power supply circuit PWR and the control circuit TCON, respectively.
One of the gate signal lines GL is sequentially selected by a scanning signal from the vertical scanning circuit V.
In addition, a video signal is supplied to each of the drain signal lines DL by the video signal driving circuit He in accordance with the selection timing of the gate signal line GL.

  In the above-described embodiment, the vertical scanning drive circuit V and the video signal drive circuit He indicate the semiconductor device mounted on the transparent substrate SUB1, but for example, straddle between the transparent substrate SUB1 and the printed circuit board. It may be a so-called tape carrier type semiconductor device to be connected. Further, when the semiconductor layer of the thin film transistor TFT is made of polycrystalline silicon (p-Si), the transparent substrate SUB1 is made of the polycrystalline silicon. A semiconductor element may be formed together with a wiring layer.

<Pixel configuration>
FIG. 1C is a cross-sectional view showing an embodiment of the configuration of the pixel region.
In FIG. 1C, the gate signal line GL, the drain signal line DL, the thin film transistor TFT, and the like are omitted, and only the pixel electrode PX and the counter electrode CT in the pixel region are shown.
That is, a pixel electrode PX is formed in a pixel region on the liquid crystal side surface of the transparent substrate SUB1, and the pixel electrode PX is, for example, ITO (Indium Tin Oxide), ITZO (Indium Tin Zinc Oxide), or IZO (Indium Zinc Oxide). , SnO2 (tin oxide), In2O3 (indium oxide), and the like.

In this case, the pixel electrode PX is not formed on the entire surface of the pixel region, and has a portion where the pixel electrode PX is not formed.
An alignment film AL1 is formed on the upper surfaces of the pixel electrodes PX so as to cover the pixel electrodes PX, and the alignment film AL1 is formed of a resin film on which the so-called rubbing treatment is not performed.

Further, a counter electrode CT formed in common for each pixel is formed on the liquid crystal side surface of the transparent substrate SUB2 arranged to face the transparent substrate SUB1 via liquid crystal. The counter electrode CT is formed of a light-transmitting conductive layer like the pixel electrode PX.
An alignment film AL2 is formed on the upper surface of the counter electrode CT so as to cover the counter electrode CT, and the alignment film AL2 is formed of a resin film on which the so-called rubbing process is not performed.

  FIG. 1C illustrates the behavior of liquid crystal molecules when an electric field E is generated slightly between the pixel electrode PX and the counter electrode CT, but when the electric field E is not generated, FIG. The alignment films AL1 and AL2 align the liquid crystal molecules in a direction perpendicular to the transparent substrates SUB1 and SUB2.

<Video signal>
FIG. 1D shows a video signal supplied from the video signal driving circuit He to each video signal line DL. For simplicity, the video signal is formed by sequentially repeating a signal having the lowest voltage and the highest voltage. Is shown. Therefore, a voltage signal indicating gradation is not shown.
Note that this video signal shown in FIG. 1D is shown as a voltage difference with respect to the reference voltage supplied to the counter electrode CT, in other words, as a voltage difference between the counter electrode CT and the pixel electrode PX. It is the same even if grasped.

The video signal is supplied with a signal having a voltage of 20% or less with respect to the maximum voltage at regular time intervals.
The voltage of 20% or less is a signal for erasing an unexpected stain display in that portion, for example, when the liquid crystal display AR of the liquid crystal display device is touched with a finger, for example.

Here, the video signal shown in FIG. 1D is a video signal based on the reference signal supplied to the counter voltage CT. However, the video signal is not limited to this, as shown in FIG. It goes without saying that a signal having a reverse polarity, that is, a reference signal for a video signal supplied to the pixel electrode PX may be mixed with a signal having a voltage of 20% or less with respect to the maximum voltage at regular intervals. Nor.
Furthermore, as shown in FIG. 3, it is needless to say that the signal shown in FIG. 1 (d) and the signal shown in FIG.

<Discussion>
In the above-described embodiments, for example, a normally black one is used as the liquid crystal display device. Here, normally black refers to a mode in which black display is performed without applying an electric field between the pixel electrode PX and the counter voltage CT.
Then, at a fixed time, a maximum voltage, that is, a voltage that is 20% or less of the voltage that gives a black display is applied to each video signal line DL as an erasing voltage.
As a result, even if the liquid crystal display AR of the liquid crystal display device is touched with a finger, the stored image can be erased within a certain time, and normal display is realized.
In this embodiment, the erase voltage per pixel is applied twice or less per second. Usually, a liquid crystal display device is driven with a frame frequency of 60 Hz or more. This means that the voltage is written to each pixel 60 times per second.

On the other hand, the human eye has a visual characteristic that an image of 1/24 seconds or less is not recognized as an independent image. For example, by displaying different still images 24 times per second, A video system that creates an illusion as a continuous image rather than as an animation is widely known as animation.
Therefore, even if an erasing voltage is applied twice or less per second, that is, once or every 30 times, the resulting image is not recognized by human eyes.
As a result, in this embodiment, the memory image can be eliminated by the vertical alignment method without the user perceiving the insertion of the image.
The frequency of inserting the erasing voltage is preferably once or more per minute. This is because the user can erase the phenomenon before starting to consider it as a defect, and thus can prevent the user from being given unnecessary anxiety.

Furthermore, about once every 5 seconds is desirable. If the panel is pushed, the distance between the substrates decreases and this gradually recovers. Since the distance between the substrates is different until the recovery, the display image looks different in the area. This is a phenomenon that occurs also in liquid crystal display devices other than the vertical alignment method.
Therefore, if an erasing voltage is applied at a rate of once every 5 seconds, it cannot be distinguished from a normal phenomenon that occurs in liquid crystal display devices other than the vertical alignment method, so that the user is aware of the existence of this phenomenon. Can not be perceived.

Furthermore, as a display mode, any of 1) a normally white mode in which the voltage is small and bright and large and dark can be applied, and 2) a normally black mode in which the voltage is small and dark and large and bright can be applied.
Here, in the case of 2), the luminance is reduced by the period of time when the erasing voltage is applied, but the amount of reduction is very small because the frequency of erasing voltage application is low.
Further, in the case of 1), the contrast ratio is lowered by increasing the luminance for the period by applying the erasing voltage. For this reason, about once every 5 seconds or about once every 5 seconds to 1 minute is desirable.

  Here, as shown in FIG. 4, it is needless to say that gradation display corresponding to a voltage of 20% or less may be performed as an erasing signal. That is, by using a voltage or gradation corresponding to white in the normally white mode and a voltage or gradation corresponding to black in the normally black mode for erasing, the time required for erasing can be further reduced.

Example 2
FIG. 5 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention, and shows a flowchart for inputting the erasing data. The operation according to this flowchart is performed by the control circuit TCON. Yes.
In FIG. 5, first, in step 1 (ST1), it is determined in step 2 (ST2) whether or not the counter is 0 and a synchronization signal is input.
When the synchronization signal is input, the counter value is incremented by 1 in step 3 (ST3), and it is determined in step 4 (ST4) whether the value is larger than the set value.
If the value is not larger than the set value, the process returns to step 2 (ST2) and waits for the input of the next synchronization signal.
If the value is larger than the set value, the video signal is changed to erasure data in step 5 (ST5), and the process returns to step 1 (ST1) to set the counter to 0. This is repeated below.

The synchronization signal may be any signal as long as it corresponds to the passage of time depending on the count number, and the set value is a predetermined time for outputting the erasing data. It is set as a value corresponding to the count number.
In this case, the set value may be set externally with respect to the control circuit TCON. For example, as shown in FIG. 6, a setting terminal may be provided in the control circuit TCON so that the set value can be changed by short-circuiting or opening the terminals.
In this case, for example, even when either the normally white mode or the normally black mode is used, one type of TCON can be used.

Example 3
FIG. 7 is a main part explanatory view showing another embodiment of the liquid crystal display device according to the present invention and is a view showing a supply mode of a video signal mixed with erase data.
In FIG. 7, the erase data is applied to the drain signal line DL in units of one line, and as a result, the erase data is entered in all the lines by the sequential scanning of the gate signal line GL.
Here, one line refers to each pixel group driven by the scanning signal of one gate signal line GL.
As shown in FIG. 8, erasing data may be applied to the drain signal line DL in units of a plurality of lines. By doing so, the display time of the erasure data can be shortened. For this reason, the erasing data may be displayed for a longer time.
Further, as shown in FIG. 9, all the lines may be simultaneously applied to the drain signal line DL. By doing so, the display time of the erasure data can be further shortened.

Example 4
FIG. 10 is a main part explanatory view showing another embodiment of the liquid crystal display device according to the present invention and is a diagram showing a mode of supplying erase data.
As shown in FIG. 10, the liquid crystal display AR is divided into a plurality of (for example, six in the figure) areas, and erasing data is applied in units of areas.
In this case, for example, in the first frame, erase data is input to three regions that are not adjacent to each other among the six divided regions, and in the next frame, other three regions other than the three regions are input. Is input to the erasure data, and this is repeated thereafter.
In this case, since the area to which the erasure data is added becomes random, it is possible to make the display with the erasure data difficult to see.

For the same purpose, as shown in FIG. 11, the liquid crystal display AR is divided into, for example, three regions arranged in parallel in the y-axis direction, and one of the three regions divided in the first frame. Erase data is input to one area, in the next frame, erase data is input to one of the other two remaining areas, and erase data is input to the other area in the next frame. This may be repeated.
Any of these configurations can be easily realized by extension in the control circuit TCON.

Example 5 FIG.
FIG. 12 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention and corresponds to FIG.
1A is different from the case of FIG. 1A in that, in the region between the video signal drive circuit He and the liquid crystal display AR, each drain signal line DL has a switching element SW formed of, for example, a thin film transistor. Each of these switching elements is connected to each drain signal line DL by switching one of them, and the erasing signal line to which the erasing potential is supplied to the drain signal line DL on the liquid crystal display area AR side by switching the other. It is configured to be connected to IL. The erase signal line IL is held at the erase potential by the power supply circuit PWR.
That is, in the above-described embodiment, the erasing data is supplied from the video signal driving circuit He to each drain signal line DL, but in this embodiment, the switching element SW is driven through the switching element SW. It is intended to supply each drain signal line DL.

FIG. 13A is a plan view showing an embodiment of the switching element SW. 13B is a cross-sectional view taken along the line bb in FIG. 13A, and FIG. 13C is a cross-sectional view taken along the line cc in FIG. 13A.
The switching element SW is made of a thin film transistor TFT1, and its semiconductor layer is made of, for example, polycrystalline silicon. When the semiconductor layer of the C-MIS transistor formed in the thin film transistor TFT, the scanning signal driving circuit V, and the video signal driving circuit He of each pixel is polycrystalline silicon, the thin film transistor TFT1 of the switching element SW is, for example, each of these pixels The thin film transistor TFT and the C-MIS transistor are formed in parallel.

First, polycrystalline silicon layers P-Si (1) and P-Si (2) are formed on the upper surface of the transparent substrate SUB1. An insulating film GI is formed on the upper surfaces of the polycrystalline silicon layers P-Si (1) and P-Si (2) so as to cover the polycrystalline silicon layers P-Si (1) and P-Si (2). ing.
On the upper surface of the insulating film GI, the first gate electrode signal line GL1 traverses the polycrystalline silicon layer P-Si (1) and also traverses the polycrystalline silicon layer P-Si (2). Thus, the second gate electrode GT2 is formed. Here, the first gate electrode signal line GL1 is configured to also serve as the first gate electrode in a portion crossing the polycrystalline silicon layer P-Si (1).

Further, a protective film PAS is formed so as to cover the first gate electrode signal line GL1 and the second gate electrode GT2.
On the upper surface of the protective film PAS, a drain signal line DL (He) on the video signal driving circuit He side connected to one end of the polycrystalline silicon layer P-Si (1) is formed, and the polycrystalline silicon layer P A drain signal line DL (AR) on the liquid crystal display AR side connected to the other end of -Si (1) is formed. These connections are made by through holes TH1 and TH2 formed through the protective film PAS and the insulating film GI.

Further, the drain signal line DL (He) on the video signal driving circuit He side connected to one end of the polycrystalline silicon layer P-Si (2) is formed on the upper surface of the protective film PAS. An erasing signal line IL connected to the other end of the layer P-Si (2) is formed. Each of these connections is made by through holes TH3 and TH5 formed through the protective film PAS and the insulating film GI.
A second gate electrode signal line GL2 connected to the second gate electrode GT2 is formed. This connection is made by a through hole TH4 formed in the protective film PAS.

Here, the first gate electrode signal line GL1, the erasing signal line IL, and the second gate electrode signal line GL2 are respectively common to those of the other switching elements SW, and each drain signal line DL and It is running so as to be orthogonal.
The switching element SW configured in this way has each drain on the liquid crystal display portion AR side when an ON signal is supplied to the first gate electrode signal line GL1 and an OFF signal is supplied to the second gate electrode signal line GL2. A video signal is supplied to the signal line DL from the video signal driving circuit He. When an OFF signal is supplied to the first gate electrode signal line GL1 and an ON signal is supplied to the second gate electrode signal line GL2, each drain signal line DL on the liquid crystal display portion AR side is connected to the erasing signal line IL. The erasing data is supplied from.

  In the above-described embodiments, polycrystalline silicon is used as the semiconductor layer of the switching element SW. However, the present invention is not limited to this, and continuous grain boundary silicon or pseudo single crystal silicon may be used. Needless to say.

Example 6
FIG. 14 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention and corresponds to FIG.
The configuration different from the case of FIG. 12 is that a switching element SW (B) composed of, for example, a thin film transistor is interposed in each gate signal line GL in the region between the scanning signal drive circuit V and the liquid crystal display AR. The switching elements SW (B) are formed so that the signal lines DL can be connected by switching one of them, and the connection of the signal lines DL can be released by switching the other.
Each switching element SW (B) is formed with an extended signal line GL3 for turning on the gate from the power supply circuit PWR.
With this configuration, it is possible to realize batch erasure of the entire screen.

Example 7
FIG. 15 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention.
This liquid crystal display device has a configuration in which a touch panel TPNL is disposed on the observation side surface of the liquid crystal display panel LPNL so as to cover at least the liquid crystal display portion AR.

The touch panel TPNL is such that, by pressing the surface of the touch panel with a pen or the like, position information of the pressed position is output, and various operations are reflected on the display of the liquid crystal display panel LPNL based on the position information. It is.
As a configuration of the touch panel TPNL, for example, a plurality of first signal lines extending in the x direction on the surface and arranged in parallel in the y direction and a plurality of signals extending in the y direction and arranged in parallel in the x direction are provided. When the second signal line is normally insulated and a part of the second signal line is pressed, the signal line of the first signal line and the signal line of the second signal line at the part are short-circuited. The short circuit is output together with the position information.
Further, the liquid crystal display panel LPNL uses the above-described liquid crystal display device. When pressure is applied to the liquid crystal display portion AR, “stain display” occurs in that portion.

In this embodiment, when the touch panel TPNL is pressed with a pen or the like, the pressure is transmitted by the liquid crystal display panel LPNL, and “stain display” generated in the liquid crystal display panel LPNL is prevented.
That is, as shown in FIG. 15, the control circuit TCON detects position information from the touch panel TPNL pressed with a pen or the like, and the control circuit TCON supplies the pixel corresponding to the position based on the position information. The video signal is a corrected video signal having a voltage of 20% or less of the maximum voltage.
In such a configuration, as shown in FIGS. 16A, 16B, and 16C, a stain display STN is temporarily generated in a portion where the touch panel TPNL is pressed with a pen or the like, but then it disappears. Will return to the normal screen.

<Discussion>
A liquid crystal display device provided with a touch panel on the entire surface of the liquid crystal display device is widely known. The common point is that an operation of pressing the touch panel with a pen or a finger is performed.
As a result, for example, conduction or capacitance variation occurs between the upper limit electrodes configured in a matrix, and this variation is detected by a detection circuit provided around the touch panel, and the touched position on the screen is specified. It becomes like this.

However, this pressing operation applies pressure to the liquid crystal display panel, and a memory image is generated. The liquid crystal display device with a touch panel is essentially a premise of an operation of pressing.
However, the degree of force with which the touch panel is pressed depends on the individual, and it is difficult to assume the pressure applied to the liquid crystal display panel.
Therefore, in order to provide a constantly stable display with a touch panel in a vertical alignment type liquid crystal display device, a configuration for eliminating the memory property described above is required.

Therefore, when at least one of the above-described embodiments is configured as a liquid crystal display device with a touch panel, it is possible to obtain a stable display by a vertical alignment method.
In the touch panel system, the position information to which pressure is applied is specified, and the memory image is generated only in the touched area. Therefore, it is only necessary to apply a voltage of 20% or less to the area.

In this case, the image data in the area corresponding to the address and in the vicinity thereof only needs to be set to a voltage of 20% or less, so that the data can be replaced with TCON, and a simple configuration can be obtained.
For simplicity, white may be used for normally white, and black gradation may be used for normally black.
Needless to say, the replacement of the video signal may be continuously performed when the position information from the touch panel TPNL is added.

Example 8 FIG.
FIG. 17 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention and corresponds to FIG.
A configuration different from the case of FIG. 16 is that after the touch panel TPNL is pressed with a pen or the like, “stain display” is erased after at least 0.1 second or more has elapsed. In other words, when the touch panel TPNL is pressed with a pen or the like, the control circuit TCON detects position information, and then, after lapse of 0.1 second or more, erase data is sent from the control circuit TCON to the liquid crystal display panel LPNL. ing.

FIG. 18 is a flowchart showing an embodiment of the operation performed by the control circuit TCON.
In the figure, first, a touch address is detected by SP1 based on information from the touch panel TPNL. Thereafter, the address data is stored in the storage area indicated by SP3 by SP2.
Next, at SP4, the stored address is compared with the input data. At SP5, the counter is started, and at SP6, the count number is added as data is input.
When the count number reaches a value corresponding to 0.1 seconds at SP7, the video signal data in the area corresponding to the storage address is replaced at SP8.
If the stored address data is input at SP4, the process returns to SP1 and is repeated until the stored address data is not input.

<Discussion>
Since the touch operation on the touch panel TPNL is performed by a human, the time during which pressure is applied by the touch operation is not instantaneous but is a continuous time having a finite value.
Even if the screen is erased while touching, the memory is generated again, so it is not meaningful. Accordingly, in order to add the erase data after the touch is completed, it is desirable to perform the setting after the elapse of 0.1 second or longer.
Thereby, it is possible to achieve reliable screen erasure of the area immediately after the touch is completed.

Example 9
FIG. 19 is a block diagram showing another embodiment of the liquid crystal display device according to the present invention and corresponds to FIG.
The configuration different from the case of FIG. 17 is such that when the touch panel TPNL is first traced with a pen or the like, the locus drawn by the pen or the like is directly displayed as a display. This display is the “stain display” described above, but this stain display is validated as a display.
This display is erased with support from the operator. That is, the locus drawn by a pen or the like can be used for some purpose, and the display is canceled when it becomes unnecessary.

FIG. 20 is a flowchart showing an embodiment of the operation performed by the control circuit TCON.
In the figure, a touch address from the touch panel TPNL is detected at SP1. Then, the address data is stored in SP2. In this case, the address data is stored in the storage area indicated by SP3.
In this case, the locus drawn by the pen or the like is displayed and revealed, and a request for deleting the display is awaited.
If there is an erasure request at SP4, the video signal data in the area corresponding to the storage address is replaced at SP5. Thereafter, the address data in the storage area is reset at SP6.
In this case, the erasing signal may be performed only in the vicinity of the touch area. In this way, it is possible to configure without affecting the image other than the touch part.

FIG. 21 is a flowchart showing an embodiment of the operation performed by the control circuit TCON, and a part of FIG. 20 is extracted.
As shown in this figure, when there is an erasure request in SP4, the entire screen is erased, for example, as shown in FIG. 12 or 14 without replacing the video signal.
In this case, there is an effect that the storage area can be made unnecessary.

<Discussion>
In this embodiment, the memory property is reversed and used for display. When characters or images are described on the touch panel, it is easier to describe the characters and images when the user can see the characters or images after touching with the pen, which is convenient for the user.
Therefore, in this embodiment, the erasure is set as a user instruction, and the erasure signal is input according to the instruction from the user.
Note that the erasure request is preferably executed by software. By setting a certain address as an address for issuing a display signal, the user can issue an erasing signal simply by touching the area, thereby erasing the memory image.
Needless to say, the techniques shown in the embodiments of the liquid crystal display device not including the touch panel TPNL are applied to the liquid crystal display device including the touch panel TPNL.

It is a block diagram which shows one Example of the liquid crystal display device by this invention. FIG. 6 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and shows signals inputted to the drain signal lines. FIG. 6 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and shows signals inputted to the drain signal lines. FIG. 6 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and shows signals inputted to the drain signal lines. It is a block diagram which shows the other Example of the liquid crystal display device by this invention, and is a flowchart which shows the operation | movement of the control circuit. It is a block diagram which shows the other Example of the control circuit of the liquid crystal display device by this invention. FIG. 6 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and shows signals input to the drain signal lines in line units. FIG. 6 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and shows signals input to the drain signal lines in units of a plurality of lines. FIG. 6 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and shows signals input to the drain signal lines at the same time for all lines. FIG. 6 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and shows a signal input to the drain signal line for each frame. FIG. 6 is a configuration diagram showing another embodiment of the liquid crystal display device according to the present invention, and shows a signal input to the drain signal line for each frame. It is a block diagram which shows the other Example of the liquid crystal display device by this invention. It is a block diagram which shows one Example of a structure of the switching element comprised in FIG. It is a block diagram which shows the other Example of the liquid crystal display device by this invention. It is a block diagram which shows the other Example of the liquid crystal display device by this invention. FIG. 16 is an explanatory diagram illustrating an operation of the liquid crystal display device illustrated in FIG. 15. It is explanatory drawing which shows the other Example of the liquid crystal display device by this invention. 16 is a flowchart illustrating an example of operation of a control circuit of the liquid crystal display device illustrated in FIG. 15. It is explanatory drawing which shows the other Example of the liquid crystal display device by this invention. 20 is a flowchart illustrating an example of the operation of the control circuit of the liquid crystal display device illustrated in FIG. 19. 20 is a flowchart showing another embodiment of the operation of the control circuit of the liquid crystal display device shown in FIG. It is explanatory drawing which showed the disadvantage of the liquid crystal display device of a vertical alignment system. It is explanatory drawing which showed an example of the behavior of the liquid crystal molecule of the liquid crystal display device of a vertical alignment system. It is explanatory drawing which showed the inconvenience of the liquid crystal display device of a vertical alignment system by the behavior of the liquid crystal molecule. It is explanatory drawing which showed the behavior of the liquid crystal molecule | numerator of the liquid crystal display device of a vertical alignment system in relation to the drive voltage (0%-30%). It is explanatory drawing which showed the behavior of the liquid crystal molecule | numerator of the liquid crystal display device of a vertical alignment system in relation to the drive voltage (70%-100%). It is explanatory drawing which showed the behavior of the liquid crystal molecule | numerator of the liquid crystal display device of a vertical alignment system by the relationship of drive voltage (30%-70%).

Explanation of symbols

  SUB1 ... transparent substrate, GL ... gate signal line, DL ... drain signal line, TFT ... thin film transistor, PX ... pixel electrode, CT ... counter electrode, AR ... liquid crystal display unit, V ... scanning signal drive circuit, He ... video signal drive circuit , TCON: control circuit, PWR: power supply circuit.

Claims (5)

A first substrate and a second substrate that are arranged to face each other with a liquid crystal interposed therebetween;
A first electrode formed in a pixel region on a liquid crystal side surface of the first substrate; and a second electrode formed in a pixel region on a liquid crystal side surface of the second substrate;
Using a vertical alignment method in which liquid crystal molecules are arranged in a direction substantially perpendicular to the substrate without an electric field between the first electrode and the second electrode,
The voltage applied between the first electrode and the second electrode, 20 percent of the voltage of the maximum voltage in one minute at least some regions of the aggregate of the pixel region A liquid crystal display device comprising means for applying at least once and not more than once per second . Each of the pixels is arranged in a matrix, and each pixel is driven sequentially from a group of pixels arranged in parallel on one line to another group of pixels arranged in a direction crossing the one direction. ,
The application of more than 20% of the voltage of the maximum voltage and the first electrode is applied between the second electrode, the liquid crystal according to claim 1, characterized in that sequentially carried by one or more line unit Display device. Dividing the collection of pixel regions into a plurality of rectangular regions;
The application of more than 20% of the voltage of the maximum voltage and the first electrode is applied between the second electrode, the liquid crystal according to claim 1, characterized in that sequentially made in the rectangular area unit Display device.   The liquid crystal display device according to claim 1, further comprising a touch panel on the observation side. A voltage applied between the first electrode and the second electrode in a normally black mode in which black display is performed when an electric field is not generated between the first electrode and the second electrode. the liquid crystal display device according to claim 1, characterized in that it has 20% or less Do that voltage of the maximum voltage and the signal of the black gradation respect.

Images