JPH11212107A - Active matrix type liquid crystal display device, driving method thereof and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide an orientation division type liquid crystal display device having a wide visual angle without requiring the increment of processes. SOLUTION: Each auxiliary electrode 4 is formed in an almost center part between two pixel electrodes 3 in parallel with signal electrodes 5 and the strength of an electric field between the electrodes 4 and a counter electrode 6 is set up higher than that between the electrodes 3 and the electrode 6 so that the directions of both the electric fields are almost equal. Consequently the pixel electrodes 3 arranged on both sides of the auxiliary electrode 4 can be divided into two stable orientation areas A, B in which the inclinations of liquid crystalline molecules 7 are mutually reversed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an active matrix type liquid crystal display device for displaying an image, and more particularly to a method of driving the device and a method of manufacturing the device.

[0002]

2. Description of the Related Art In recent years, among liquid crystal display devices, in order to obtain an image with particularly high display quality, active matrix driving type liquid crystal display devices using thin film transistors as switching elements have been actively developed. . The reason is that the active matrix type liquid crystal display device can obtain a high contrast ratio regardless of the number of scanning electrodes as compared with the simple matrix driving method without a switching element. This is because an image is obtained.

In such a liquid crystal display panel of an active matrix type liquid crystal display device, there is a TN (Twisted Nematic) system as a widely used liquid crystal display mode. In the TN mode, a panel having a structure in which liquid crystal molecules are twisted by 90 ° between electrode substrates filled with a liquid crystal layer is sandwiched between two polarizing plates. The two polarizing plates have polarizing axes orthogonal to each other, and one polarizing plate is arranged so that its polarizing axis is parallel or perpendicular to the long axis direction of the liquid crystal molecules in contact with one substrate.

When no voltage is applied, white display is performed. However, when a voltage is applied between two substrates, that is, in a direction perpendicular to the liquid crystal panel, the light transmittance gradually decreases, and black display is performed. Becomes Such display characteristics are obtained because, when a voltage is applied to the liquid crystal panel, the liquid crystal molecules try to align in the direction of the electric field while distorting the twisted structure, and the light transmitted through the liquid crystal panel depends on the alignment state of the liquid crystal molecules. Is changed, and the light transmittance is modulated.

[0005] However, even in the same molecular arrangement state, the polarization state of the transmitted light changes depending on the incident direction of the light incident on the liquid crystal panel, so that the light transmittance differs according to the incident direction. That is, the characteristics of the liquid crystal panel have a viewing angle dependency, and when the viewing angle is inclined with respect to the main viewing angle direction (the major axis direction of the liquid crystal molecules in the intermediate layer of the liquid crystal layer) due to the viewing angle characteristics, Since this causes the brightness reversal phenomenon, it is an important problem in terms of the image quality of the liquid crystal panel.

In recent years, efforts to improve such viewing angle characteristics have been actively made. Among them, there is a method of laminating a phase compensator while using the TN method as the liquid crystal alignment, or an alignment division method in which one picture element has two or more TN alignment directions of the liquid crystal.

Further, as a method of improving the viewing angle characteristics by changing the orientation of the liquid crystal itself, a horizontally-aligned liquid crystal molecule is moved laterally by an in-plane electric field in the substrate plane.
lane-switching (IPS) method or Vert that aligns liquid crystal molecules perpendicular to the substrate surface and stacks a phase compensator
There is an ical-align (VA) system, and a VA alignment division system in which two or more alignment directions are provided in the VA system (for example, see K. Ohmuro et al., SID97 Digest, p845 (1997)).

[0008] Among them, the viewing angle characteristics of the IPS system and the VA alignment division system can obtain a very wide viewing angle characteristic without a luminance inversion phenomenon or a decrease in contrast. Especially V
The A-orientation division method can be operated with the same active matrix array configuration as that of the conventional TN method, and therefore, its design is easy and promising.

[0009]

However, the above-mentioned V
The A orientation division method has the following problems.

That is, in the VA alignment division system, two or more orientations in which liquid crystal molecules are aligned by applying an electric field are provided in one pixel region, and the viewing angle characteristics are made symmetric. Usually, as a method of aligning liquid crystal molecules, there is a rubbing method in which an alignment film is applied on a substrate, and rubbed thereon with a cloth such as rayon, and the liquid crystal molecules are aligned in the rubbing direction. In order to provide a region having two or more orientations, first, a first orientation such that the orientation film is oriented in a predetermined direction is provided.
After the rubbing process is performed, a resist is applied on the alignment film, and patterning is performed by a photolithography method so that only the portion where the first rubbing process is left remains, and the exposed portion of the alignment film is again The second rubbing process is performed in a direction different from the first rubbing direction, and finally, all the resists are stripped.

It is necessary to perform the above-described processing on the upper and lower substrates. Therefore, it takes a lot of time and effort to produce a liquid crystal display device of the alignment division type.
There is a problem that the yield is reduced due to the increase in the number of steps, and the production cost is increased.

An object of the present invention is to solve the above-mentioned conventional problems, and even if a VA alignment division system is adopted, the liquid crystal can be divided and aligned without increasing the division step.
It is possible to provide an inexpensive active matrix liquid crystal display device having a wide viewing angle, a driving method capable of stably maintaining liquid crystal in the active matrix liquid crystal display device, and manufacture of the active matrix liquid crystal display device. To provide a manufacturing method.

[0013]

In order to achieve the above object, according to the present invention, an auxiliary electrode is formed substantially in the center of a pixel electrode in parallel with a signal electrode, and the electric field intensity between the auxiliary electrode and a counter electrode is reduced. By setting the electric field strength higher than the electric field strength between the pixel electrode and the counter electrode and making the directions of the electric fields substantially equal, the pixel electrodes on both sides of the auxiliary electrode have a configuration in which the inclination of the liquid crystal molecules is opposite, The active matrix type liquid crystal display device has a configuration in which the two stable alignment regions A and B can be divided and formed. The liquid crystal is stabilized and the alignment is divided by the driving method and the manufacturing method. Of the liquid crystal can be divided into two regions without increasing the number of complicated manufacturing steps.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an active matrix type liquid crystal display device according to a first aspect of the present invention, a liquid crystal layer is filled between a pair of substrates facing each other, and one of the substrates is arranged in a matrix. A signal electrode and a scanning electrode, a pixel electrode electrically connected to the signal electrode via a thin film transistor, and one pixel electrode divided into two regions and arranged so as to be parallel to the signal electrode. An active matrix liquid crystal display device, comprising: a linear auxiliary electrode; and, on the other substrate, a counter electrode facing the one substrate, wherein an active matrix liquid crystal display device is provided between the counter electrode and the pixel electrode. The electric field intensity of the second electric field generated between the counter electrode and the auxiliary electrode is higher than the electric field intensity of the first electric field generated at the same time, and the direction of the first electric field and the electric field intensity of the second electric field are increased. Direction is almost equal Further, the direction of the electric field formed by the pixel electrode and the counter electrode connected to the adjacent signal electrode is made to be opposite, and by this configuration, in the pixel electrodes on both sides of the auxiliary electrode, Since the tilt of the liquid crystal molecules is opposite, the two stable alignment regions can be divided and formed.

According to a second aspect of the present invention, in the active matrix type liquid crystal display device according to the first aspect, liquid crystal molecules are aligned in a vertical direction with respect to the substrate in an initial state. .

According to a third aspect of the present invention, in the active matrix type liquid crystal display device according to the first aspect, a first thin film transistor whose switch is turned on and off by the potential of the scanning electrode is connected to the pixel electrode. The auxiliary electrode is connected to a second thin film transistor that is turned on and off by the same potential as the scanning electrode, and a first parasitic capacitance Cgd1 formed between the pixel electrode and the scanning electrode. A first storage capacitor Cst1 formed between the pixel electrode or a charge holding electrode electrically connected to the pixel electrode and a part of the scan electrode adjacent to the scan electrode; Ct1 is the sum of the pixel capacitance Cl1 and the second parasitic capacitance Cgd formed between the auxiliary electrode and the scan electrode.
2, a second storage capacitor Cst2 formed between the auxiliary electrode or a part of the scanning electrode adjacent to the auxiliary electrode and a charge holding electrode that is electrically connected to the auxiliary electrode, and a second storage capacitor Cst2 formed between the auxiliary electrode and the counter electrode. The sum with the capacitance Cl2 formed between Ct is
2, Cst1 / Ct1 <Cst2 / Ct2,
And Cgd1 / Cst1 = Cgd2 / Cst2,
Further, between the pixel electrodes adjacent to each other with the signal electrode interposed therebetween, the connected storage capacitor is formed on the same scan electrode, and one of the connected thin film transistors forms the storage capacitor. The scanning electrode is connected to a scanning electrode at a preceding stage of the scanning electrode and the other scanning electrode is connected to a scanning electrode at a subsequent stage, and a specific relationship between a storage capacitance and a parasitic capacitance according to this configuration is provided.
Can be set in the electric field relationship described in (1).

According to a fourth aspect of the present invention, there is provided a method for driving an active matrix type liquid crystal display device, the method comprising the steps of: In contrast, in one scanning period before applying the scanning signal for turning on the thin film transistor, a modulation signal having a lower potential than the potential held in the off period is applied, and after applying the scanning signal for turning on the thin film transistor. In one scanning period, a modulation signal having a higher potential than the potential held in the off period is applied, and a scanning signal for turning on a thin film transistor is applied to a scanning electrode adjacent to the one scanning electrode. During one scanning period, a modulation signal having a higher potential than the potential held during the off period is applied, and after a scanning signal for turning on is applied, the modulation signal is held during the off period during one scanning period. By applying a modulation signal of lower potential than position, an image signal supplied from the signal electrode,
A voltage obtained by superimposing a voltage generated by the modulation signal is applied to the pixel electrode, and the image signal applied to the signal electrode is inverted every scanning period, and the phase of the image signal between adjacent signal electrodes is changed. The liquid crystal device is characterized in that the liquid crystal is made different by 180 °, and by this driving method, the liquid crystal can be driven so as to be stably maintained.

According to a fifth aspect of the present invention, there is provided a method of manufacturing an active matrix type liquid crystal display device, comprising the steps of: After forming a scanning electrode, a thin film transistor is formed, then a signal electrode, a drain electrode, and a charge holding electrode are simultaneously formed, and an insulating layer is formed on the entire surface thereof, and then the drain electrode and the charge holding electrode are formed. Wherein the insulating layer on the substrate is partially removed, and thereafter, an auxiliary electrode and a pixel electrode are simultaneously formed. The active matrix type liquid crystal display device according to claim 1 can be manufactured by this manufacturing method. .

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view of a cross-sectional state of an active matrix type liquid crystal display device for explaining one embodiment of the present invention, and FIG. 2 is a schematic plan view of the active matrix type liquid crystal display device of this embodiment. FIG. 3 is a diagram showing an equivalent circuit in the configuration of FIG. 2, and FIG. 4 is a diagram of FIG.
3 is a diagram showing voltage waveforms of respective parts corresponding to the equivalent circuit shown in FIG. 3, wherein 1 and 2 are a pair of substrates, 3, 31, and 32 are pixel electrodes, 4, 41 and 42 are auxiliary electrodes, 5, 10, and 50. Is a signal electrode, 6 is a counter electrode, 7 is a liquid crystal molecule, 8 is a +2 V equipotential line, 9 is a −2 V equipotential line, 11 and 14 are TFTs (thin film transistors), 12 and 15 are parasitic capacitors, and 13 and 16.
Is the storage capacity.

As shown in FIG. 1, the feature of the active matrix type liquid crystal display device of the present embodiment is that an auxiliary electrode 4 is formed almost in the center of a pixel electrode 3 in parallel with a signal electrode 5. The electric field strength between the electrode 4 and the counter electrode 6 is higher than the electric field strength between the pixel electrode 3 and the counter electrode 6, and the directions of the electric fields are substantially equal. The direction of the electric field between the pixel electrodes 3 adjacent to each other is opposite to each other.

FIG. 1 shows the equipotential lines 8 and 9 of the liquid crystal display device and the direction in which the liquid crystal molecules 7 face in accordance with the electric field, from the electric field distribution in the above-described configuration. The liquid crystal molecules 7 have negative dielectric anisotropy used in the VA alignment division system. The liquid crystal molecules tend to orient their molecular major axes along equipotential lines according to the strength of an electric field applied above a threshold voltage.

In the example shown in FIG. 1, the pixel electrode 3 has +4
V, -4 is applied to the pixel electrodes 3 adjacent to each other with the signal electrode 5 therebetween.
V, + 6V for the auxiliary electrode 4, and-for the adjacent auxiliary electrode 4.
6 V and 0 V are applied to the counter electrode 6. FIG. 1 shows +2 V and −2 V equipotential lines 8 and 9 in such a potential distribution, respectively. Equipotential lines 8, 9
Is rapidly bent between the adjacent pixel electrodes 3 in the portion of the adjacent pixel electrode 3, and in the vicinity of the auxiliary electrode 4,
It is distorted so as to approach the counter electrode 6. In FIG. 1, the signal electrode 5 existing between the adjacent pixel electrodes 3 is formed at a position sufficiently lower than the pixel electrode 3, and the potential of the signal electrode 5 causes the adjacent pixel electrode 3 The configuration is such that the equipotential lines 8, 9 between them are not disturbed.

The liquid crystal molecules 7 where the equipotential lines 8 and 9 are distorted are tilted along the curved equipotential lines 8 and 9 respectively. That is, in FIG. 1, in the pixel electrode 3 on the left side of the auxiliary electrode 4, both the liquid crystal molecules 7 near the auxiliary electrode 4 and the liquid crystal molecules 7 on the left end of the pixel electrode 3 rotate clockwise from a direction perpendicular to the electrode. Lean on. Then, all the liquid crystal molecules 7 on the pixel electrode 3 sandwiched between the liquid crystal molecules 7 at both ends are inclined in the same direction as the liquid crystal molecules 7 at both ends, although not shown. Similarly, the liquid crystal molecules 7 on the right side of the auxiliary electrode 4 tilt so as to rotate counterclockwise from the vertical direction.
According to such an orientation principle, in the pixel electrodes 3 on both sides of the auxiliary electrode 4, the liquid crystal molecules 7 are divided into two orientation regions A and B where the inclinations of the liquid crystal molecules 7 are opposite to each other.

Further, when a DC voltage of the same polarity is applied for a long time to the liquid crystal, a luminance drop or an afterimage occurs as a display image, that is, a so-called burning phenomenon occurs. Therefore, it is necessary to drive the liquid crystal by AC. In an active matrix type liquid crystal display device, the potential written in one scanning period is generally applied to the pixel electrode 3 for about 16 ms, which is one field period.
After holding ec, a potential is applied so that the direction of the electric field between the pixel electrode 3 and the counter electrode 6 is reversed in the next one field period. In other words, the voltage between the pixel electrode 3 and the counter electrode 6 is driven by an alternating current of about 30 Hz. In the present embodiment, the direction of the electric field between the auxiliary electrode 4 and the counter electrode 6 is also
Since the directions of the pixel electrode 3 and the counter electrode 6 must always be the same, the voltage between the auxiliary electrode 4 and the counter electrode 6 is also changed to 30 Hz AC drive in phase with the voltage between the pixel electrode 3 and the counter electrode 6. There is a need to.

In order to realize the above configuration,
An embodiment of an active matrix type liquid crystal display device according to the present invention, a driving method thereof, and a manufacturing method will be described in detail with reference to FIGS.

FIG. 4 shows scanning electrodes 21 and 2 wired in a matrix (m, n) corresponding to the equivalent circuit shown in FIG.
2, 23 voltage waveforms Vg (m-1), Vg (m), Vg
(M + 1) and the voltage waveform Vs (n) of the signal electrodes 10 and 50
-1), Vs (n), the voltage waveform Vc of the counter electrode 6 and the voltage waveform Vp (m, n-
1) and the voltage waveform Vp (m,
n) and the voltage waveform Vps applied to the auxiliary electrode 41
(M, n-1) and the voltage waveform Vps (m, n) applied to the auxiliary electrode 42 are shown.

Of the pixels arranged in the matrix,
The first TFT 11 whose switch is turned on and off by the potential of the scanning electrode 23 is connected to the pixel electrode 31 arranged at the position of (m, n−1), and the auxiliary electrode 41 is connected to the same scanning electrode 23. A second TFT 14 whose switch is turned on and off by a potential is connected, and a first parasitic capacitance (Cgd) formed between the pixel electrode 31 and the scanning electrode 23 is connected.
1) 12, the pixel electrode 31 or the charge holding electrode electrically connected to the pixel electrode 31, and the scan electrode 2 preceding the scan electrode 23
2 and a first storage capacitor (Cst
1) The sum Ct1 of 13 and the pixel capacitance (Cl1) formed between the pixel electrode 31 and the counter electrode 6 is calculated as (Ct1 = Cl1).
+ Cst1 + Cgd1), and the second parasitic capacitance (Cgd2) 1 formed between the auxiliary electrode 41 and the scan electrode 23.
5, a second storage capacitor (Cst2) 16 formed between the auxiliary electrode 41 or a part of the scanning electrode 22 in the preceding stage and a charge holding electrode electrically connected to the auxiliary electrode 41;
When the sum Ct2 of the capacitance (Cl2) formed between the counter electrode 1 and the counter electrode 6 is (Ct2 = Cl2 + Cst2 + Cgd2), the relationship is represented by (Equation 1).

[0029]

Cst1 / Ct1 <Cst2 / Ct2, Cgd1 / Cst1 = Cgd2 / Cst2 Further, the pixel electrode 31 arranged at the position (m, n-1) and the signal electrode 50 are adjacent to each other. (M,
In the pixel electrode 32 arranged at the position n), the first T which switches on and off according to the potential of the scanning electrode 21 is provided.
FT11 is connected, and the same scanning electrode 2 is
The second TFT whose switch is turned on and off by the potential of 1.
14, a first parasitic capacitance (Cgd1) 12 formed between the pixel electrode 32 and the scanning electrode 21;
A first storage capacitor (Cst1) 13 formed between the pixel electrode 32 or a charge holding electrode electrically connected to the pixel electrode 32 and a part of the scanning electrode 22 at a subsequent stage of the scanning electrode 21; The sum Ct1 with the pixel capacitance (Cl1) formed between the electrode 6 and (Ct1 = Cl1 + Cst1)
+ Cgd1), the second parasitic capacitance (Cgd2) 15 formed between the auxiliary electrode 42 and the scanning electrode 21, the charge holding electrode electrically connected to the auxiliary electrode 42 or the auxiliary electrode 42, and the subsequent scanning electrode 22. The second formed between the part
(Ct2 = Cl2 + Cst2 + Cgd2) when the sum Ct2 of the storage capacitance (Cst2) 16 of the above and the capacitance (Cl2) formed between the auxiliary electrode 42 and the counter electrode 6 is
It is configured so that the same relationship as in (Equation 1) is obtained (Equation 2).

[0030]

## EQU2 ## Cst1 / Ct1 <Cst2 / Ct2, Cgd1 / Cst1 = Cgd2 / Cst2 Then, a driving method by voltage application as shown in FIG. 4 is adopted for the active matrix liquid crystal display device having such a configuration. (For example, Tsuda., Monthly LCD Intelligen
ce July 97 p69).

In this driving, a modulation signal is applied in addition to the scanning signal for turning on the TFT, and the magnitude of the modulation signal is changed between the adjacent scanning electrodes 21, 22, and 23, respectively. A voltage obtained by superimposing a voltage generated from the modulation signal on top of the signal voltage supplied from the pixel electrode 31 and the auxiliary electrode 4
This is a driving method to be applied to the first and the second.

In FIG. 4, the scanning voltage waveform Vg (m-
1), Vg (m) and Vg (m + 1) have four voltage levels of modulation signals Vg (+) and Vg (-) in addition to Vgon for turning on and off Vgoff for switching the TFT. As shown, the modulation signals Vg (+) and Vg (-) are applied for one scanning period before and after the voltage of one scanning period Vgon is applied, and thereafter, Vgoff is applied.
Is applied. In the same field, V
The modulation signal applied before gon is Vg (m-1),
If Vg (m) is Vg (+), Vg (m) is Vg (-), and the modulation signal applied after Vgon is Vg (m-1), Vg (m + 1). V
For g (-), Vg (m) is Vg (+). Then, this modulated signal is V
The context of g (+) and Vg (-) with respect to Vgon is applied alternately.

The signal voltage waveforms Vs (n-1), Vs
(N) indicates, for each scanning period, a positive polarity Vs (+) and a negative polarity Vs with respect to the common electrode voltage Vc.
(−) Voltage is applied, and Vg is applied every field.
The positive and negative polarities when turning on are reversed.
Further, between adjacent signal electrodes, the voltage waveform V
The phases of s (n-1) and Vs (n) are different by 180 °.

In the configuration shown in FIG. 2, the voltage Vp (m, n-1) applied to the pixel electrode 31 and the voltage Vps (m, n-1) applied to the auxiliary electrode 41 are Vg (m). V
In the case of gon, after Vs (+) is written in a certain field, the voltage fluctuation of Vg (m) and Vg (m +
With the voltage fluctuation of 1), the potential fluctuates so that the sum of the electric charges of the respective capacitors at the time of writing is preserved. That is, Vg (m) and Vg (m + 1) both become Vgoff, and Vp (m, n-1),
Vps (m, n-1) also settles at a constant voltage. At this time, the potentials of Vp (m, n-1) and Vps (m, n-1) are as shown in the following equations (Equation 3) and (Equation 4).

[0035]

(Equation 3)

[0036]

(Equation 4)

Therefore, the voltage of the second term on the right side in each of (Equation 3) and (Equation 4) is superimposed on Vs (+) by the voltage of Cst1 / Ct in the configuration of this embodiment.
Since 1 <Cst2 / Ct2, the potential of Vps (n) is higher than that of Vp (n).
The potential difference between the auxiliary electrode 41 and the counter electrode 6 can be made larger than the potential difference between the counter electrode 1 and the counter electrode 6. In the next field, the potential is expressed by the following equations (Equation 5) and (Equation 6).

[0038]

(Equation 5)

[0039]

(Equation 6)

The pixel electrode 31 and the counter electrode 6
The potential difference between the auxiliary electrode 41 and the counter electrode 6 is larger than the potential difference between them.

Similarly, when the potential Vp (m, n) of the pixel electrode 32 adjacent to the pixel electrode 31 and the potential Vps (m, n) of the auxiliary electrode 42 are obtained, the potential of the pixel electrode 31 becomes When written as

[0042]

(Equation 7)

## EQU5 ## It can be seen from the equation (5) that the polarities of the pixel electrode 31 and the pixel electrode 32 are inverted.

Similarly, for the auxiliary electrode 42, when the auxiliary electrode 41 is represented by the potential of (Equation 4),

[0045]

(Equation 8)

## EQU5 ## The formula is the same as that of (Formula 6), and the polarities of the auxiliary electrode 41 and the auxiliary electrode 42 are inverted. Also in the next field, the polarity is similarly inverted between the adjacent pixel electrodes 31 and 32 and between the auxiliary electrodes 41 and 42.

As described above, the equipotential lines 8 and 9 as shown in FIG. 1 can be always realized.

Further, Vgd1 / Vct1 = Vgd2 /
By setting Vct2, the potential of the pixel electrodes 31, 32 and the potential of the auxiliary electrodes 41, 42 can be driven symmetrically with respect to the potential of the counter electrode 6, so that the DC component is not superimposed. In addition, the liquid crystal can be kept stable.

Next, one embodiment of a method of manufacturing the active matrix type liquid crystal display device having the above configuration will be described with reference to FIGS.

In this embodiment, first, SiO ₂ (not shown) is formed on the front surfaces of the substrates 1 and ₂ , and then the scan electrodes 21 and 2 are formed.
Patterns 2 and 23 are formed using chromium by photolithography at predetermined intervals as shown in the figure. Note that the material is not limited to chromium, and a conductive single-layer film or a multilayer film such as aluminum or a metal containing aluminum as a main component may be used.

Next, on the scanning electrodes 21, 22, 23,
An insulator layer such as, for example, silicon nitride (SiN _x ) that acts as a gate insulating film in a TFT that functions as the first TFT 11 connected to the pixel electrodes 31 and 32 and the second TFT 14 connected to the auxiliary electrodes 41 and 42. (Not shown). Further, on the insulator layer, for example, an amorphous silicon (α-Si) semiconductor layer which functions as a switch in the TFT is laminated.

Thereafter, two layers of titanium / aluminum (Ti / Al) are deposited on the semiconductor layer, and the signal electrodes 10 and 5 are deposited.
The pattern is formed such that 0 is substantially orthogonal to the scanning electrodes 21, 22, and 23, and is substantially parallel to each other. Further, drain electrodes of the first TFT 11 and the second TFT 14 are also formed so as to partially overlap the semiconductor layer. At this time, the parasitic capacitances (Cgd1) 12 and (Cgd2) 15 are simultaneously formed between the scan electrodes 21, 22, 23 and the drain electrode in such a shape as to have a predetermined capacitance value. Further, the storage capacitors (Cst1) 13, (Cs1) are stacked on the scan electrodes 21, 22, 23 so as to have a predetermined area.
t2) 16 is formed to have a predetermined capacitance value. Note that the material is not limited to titanium / aluminum (Ti / Al), and a single-layer film or a multilayer film of a conductive metal may be used.

Thereafter, an acrylic resin is laminated on the entire surface, and the polyimide on the drain electrode and the storage capacitors (Cst1) 13 and (Cst2) 16 is partially removed into a predetermined shape by photolithography. Finally, an ITO film is formed, and pixel electrodes 31 and 32 are formed by photolithography.
And, the auxiliary electrodes 41 and 42 are formed in a predetermined shape. The pixel electrodes 31 and 32 and the auxiliary electrodes 41 and 42 have a drain electrode in a portion where the polyimide has been removed,
The storage capacitors (Cst1) 13 and (Cst2) 16 are connected.

An alignment film (for example, ODS-E manufactured by Chisso Corporation) for vertically aligning one substrate 1 on which the active matrix array is formed as described above and the other substrate 2 on which the counter electrode 6 is formed. ) Is applied to one side of the electrodes, and the two substrates 1 and 2 are attached to each other. Then, a liquid crystal having a negative dielectric anisotropy is filled between the substrates 1 and 2,
An active matrix liquid crystal display device can be manufactured.

As the capacitance value of each part, Cgd1 = 0.
1 pF, Cst1 = 0.5 pF, Cl1 = 0.4 pF,
Cgd2 = 0.06 pF, Cst2 = 0.3 pF, Cl
It was set so that 2 = 0.04 pF. Therefore, C
gd1 / Cst1 = Cgd2 / Cst2 = 0.2, and at the same time, Cst1 / Ct1 = 0.5, Cst2 / C
t2 = 0.75, and Cst1 / Ct1 <Cst2
/ Ct2 could be satisfied.

In the active matrix type liquid crystal display device having such a configuration, the scanning electrodes 21, 22, 23 are provided with:
Vgon = 15V, Vgoff = −15V, Vg (+)
= −10 V, Vg (−) = − 26 V, and Vs (+) = 2 V, Vs to the signal electrodes 10 and 50
An image signal of (−) = − 2 V is applied, and V
When c = 0 V is applied, the potential of the pixel electrode 3 becomes Vp
(N) = ± 6 V, and the potential of the auxiliary electrode 4 is Vps (n) = ±
8V, and the potential difference 6 between the pixel electrode 3 and the counter electrode 6 is calculated.
V, the potential difference between the auxiliary electrode 4 and the counter electrode 6 is 8 V
And could be set to be higher.

Driving in such a setting, and observing the orientation of the liquid crystal on the pixel electrode 3 as shown in FIG.
Two alignment regions A and B appeared at the boundary of the auxiliary electrode 4. Further, when the liquid crystal display device was observed with a polarizing microscope under crossed Nicols while being tilted, the tilt angle at which the extinction position was obtained in the two alignment regions A and B was symmetrical with respect to the normal direction of the substrate. It is confirmed that
It was verified that the liquid crystal molecules 7 in the two alignment regions A and B were inclined in directions symmetric with respect to the normal direction of the substrate as shown in FIG.

[0058]

As described above, according to the active matrix type liquid crystal display device of the present invention, the method of driving the same, and the method of manufacturing the same, the alignment of the liquid crystal can be adjusted without increasing the number of complicated manufacturing steps for dividing the alignment. An active matrix type liquid crystal display device having a wide viewing angle characteristic can be stably divided into two regions, and the liquid crystal can be stably maintained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a cross-sectional state of an active matrix type liquid crystal display device for describing an embodiment of the present invention.

FIG. 2 is an explanatory view schematically showing a planar configuration of an active matrix type liquid crystal display device according to the embodiment.

FIG. 3 is a diagram showing an equivalent circuit in the configuration of FIG. 2;

FIG. 4 is a diagram showing voltage waveforms of respective parts corresponding to the equivalent circuit shown in FIG.

[Explanation of symbols]

 1, 2 substrate 3, 31, 32 pixel electrode 4, 41, 42 auxiliary electrode 5, 10, 50 signal electrode 6 counter electrode 7 liquid crystal molecule 8 + 2V equipotential line 9 -2V equipotential line 11,14 TFT (thin film transistor) ) 12,15 Parasitic capacitance 13,16 Storage capacitance

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G09F 9/30 343 G09G 3/36 G09G 3/36 G02F 1/137 505

Claims (5)

[Claims] 1. A liquid crystal layer is filled between a pair of substrates facing each other, and one of the substrates is electrically connected to signal electrodes and scanning electrodes arranged in a matrix form via a thin film transistor. And a linear auxiliary electrode that divides the one pixel electrode into two regions and is arranged to be parallel to the signal electrode. An active matrix type liquid crystal display device provided with a counter electrode opposed to a substrate, wherein the counter electrode and the auxiliary electrode are arranged to be smaller than an electric field intensity of a first electric field generated between the counter electrode and the pixel electrode. And increasing the electric field strength of the second electric field generated between the first electric field and the first electric field.
And the direction of the second electric field are made substantially equal, and the direction of the electric field formed by the pixel electrode and the counter electrode connected to the adjacent signal electrode is made opposite. Active matrix type liquid crystal display device. 2. The active matrix type liquid crystal display device according to claim 1, wherein the liquid crystal molecules are initially oriented in a direction perpendicular to the substrate. 3. The pixel electrode is connected to a first thin-film transistor whose switch is turned on and off by the potential of the scanning electrode, and the auxiliary electrode is turned on and off by the same potential as the scanning electrode. 2 thin film transistors are connected to a first parasitic capacitance Cgd1 formed between the pixel electrode and the scan electrode, and a charge holding electrode and the scan electrode that are electrically connected to the pixel electrode or the pixel electrode. A first storage capacitor Cs formed between a part of an adjacent scanning electrode
The sum of t1 and a pixel capacitance Cl1 formed between the pixel electrode and the counter electrode is defined as Ct1, and a second parasitic capacitance Cgd2 formed between the auxiliary electrode and the scan electrode; A second storage capacitor Cst2 formed between an electrode or a charge holding electrode electrically connected to the auxiliary electrode and a part of the adjacent scanning electrode; and a second storage capacitor Cst2 formed between the auxiliary electrode and the counter electrode. Capacity Cl
Ct2 / Ct1 <Cs, where Ct2 is the sum of
t2 / Ct2, and Cgd1 / Cst1 = Cgd2 / C
The storage capacitor connected between the pixel electrodes adjacent to each other across the signal electrode is formed on the same scan electrode, and one of the connected thin film transistors is one of the storage capacitors. 2. The active matrix type liquid crystal display device according to claim 1, wherein the first and second scanning electrodes are connected to a scanning electrode at a preceding stage and the other scanning electrode is connected to a subsequent scanning electrode. 4. A driving method for driving an active matrix type liquid crystal display device according to claim 3, wherein one scan before applying a scan signal for turning on a thin film transistor to one scan electrode. During the period, a modulation signal having a potential lower than the potential held during the off period is applied, and a modulation signal having a higher potential than the potential held during the off period is applied during one scanning period after the scanning signal for turning on is applied. A modulation signal having a higher potential than a potential held in an off period during one scanning period before a scanning signal for turning on a thin film transistor is applied to a scanning electrode adjacent to the one scanning electrode. By applying a modulation signal having a potential lower than the potential held during the off period during one scanning period after applying the scanning signal for applying and turning on, the signal is supplied from the signal electrode. A voltage in which a voltage generated from the modulation signal is superimposed on the image signal is applied to the pixel electrode, and the image signal applied to the signal electrode is inverted every scanning period, and an image is generated between adjacent signal electrodes. A method for driving an active matrix liquid crystal display device, characterized in that the phases of signals are made different by 180 °. 5. A manufacturing method for manufacturing an active matrix type liquid crystal display device according to claim 1, wherein a scanning electrode is formed on one of the substrates, a thin film transistor is formed, and then a signal electrode and a drain are formed. An electrode and a charge holding electrode are simultaneously formed, and an insulating layer is formed on the entire surface thereof.Then, the insulating layer on the drain electrode and the charge holding electrode is partially removed. A method for manufacturing an active matrix liquid crystal display device, wherein pixel electrodes are simultaneously formed.