JP2003287735A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively and reliably perform transfer from splay alignment to bend alignment, in an active matrix type liquid crystal display device using bend alignment. <P>SOLUTION: Initialization of liquid crystal alignment from splay alignment to bend alignment is performed in a short period time by repeating voltage application and voltage non-application to liquid crystal molecules on pixel electrodes contributing to display and repeating voltage application and voltage non-application also to liquid crystal molecules on wirings not contributing to display, in the active matrix type liquid crystal display device. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display element widely used at present is a twisted nematic (TN) type liquid crystal display element in which liquid crystal molecules have a twisted arrangement in the element. This TN
Type liquid crystal display element has a slow response speed at the time of switching the display, and also has poor display performance when the screen is viewed from an oblique direction, that is, viewing angle characteristics are poor. Therefore, optical compensation bend alignment (OCB: Optically Compensated Bend or Optically Compensated Birefringence) type liquid crystal display devices have been proposed. In this OCB type liquid crystal display element, the liquid crystal in the element is arranged in parallel with the substrate constituting the element, the movement of the liquid crystal molecules by applying an electric field to the liquid crystal, and the retardation film and the polarization plate installed outside the substrate. It is displayed by a plate.

The operating principle of the OCB type liquid crystal display element will be described with reference to FIG. In FIG. 9, 1 is a pair of substrates, 2 is an electrode, and liquid crystal is filled in the portions sandwiched by the substrates. Further, in FIG. 9, 6 represents liquid crystal molecules. Although not shown in FIG. 9, in an actual display device, a polarizing plate is generally installed outside the substrate 1. In order for the OCB type liquid crystal display device to operate normally, the liquid crystal molecules in the device must have a liquid crystal molecule arrangement called a bend arrangement as shown in FIG. 9 or 10. When a voltage is applied between the electrodes of both substrates in the state of FIG. 9, liquid crystal molecules are arranged as shown in FIG. 10 due to the action of the electric field, and display is performed by the optical characteristic difference between the states of FIG. 9 and FIG. There is.

In order to arrange the liquid crystal molecules parallel to the substrate, a method called rubbing treatment described below is generally used. In FIG. 11, the surface of the electrode 2 is coated with a polyimide resin with a thickness of several hundred angstroms. The substrate coated with the resin is surface-treated by rubbing it in one direction with a cloth before assembling it into the liquid crystal element. The pair of substrates which have been subjected to the surface treatment are opposed to each other with a spacer resin for keeping a constant gap between the two substrates sandwiched therebetween, and the peripheral portions of the substrates are fixed by the resin. A liquid crystal material is injected between the pair of substrates thus formed by vacuum injection or the like. Liquid crystal molecules of the injected liquid crystal material are arranged in the direction in which the rubbing treatment is performed on the surface of the polyimide resin. In FIG. 11, the liquid crystal molecules are oriented in a direction slightly inclined from the substrate surface, and this direction is determined by the direction of rubbing treatment. For example, as shown in FIG. 11, in order to arrange the liquid crystals, rubbing treatment can be performed in the direction of arrow 9 in FIG. When the substrate surface is rubbed, the liquid crystal molecules tend to be arranged in parallel to the substrate.Therefore, in the liquid crystal display device configured as above, the initial state in which no voltage is applied to the electrodes Then, the liquid crystal molecules are arranged as shown in FIG. In order to operate the OCB type liquid crystal display device normally, it is necessary to change the molecular arrangement state for displaying from the molecular arrangement state shown in FIG. 11 as shown in FIG. 9 or 10.

[0005]

As described above, in the OCB type liquid crystal display element, it is necessary to change the molecular alignment state from the initial alignment state in which no voltage is applied to the alignment state used for display. In a liquid crystal display element having a large number of display pixel electrodes, it is necessary to generate this array change with good yield in all individual pixels. In the bend alignment state shown in FIGS. 9 to 10, the liquid crystal molecules in the vicinity of the middle of the liquid crystal layer are aligned vertically to the substrate. On the other hand, in FIG. 11, which is the initial alignment state in which no voltage is applied, the liquid crystal is horizontally aligned. When a voltage is applied to the alignment state shown in FIG. 11, a liquid crystal alignment state having a horizontal alignment at the central portion in the thickness direction of the panel, which is called an asymmetric splay alignment, is transiently generated as shown in FIG. The state transition of the alignment change from this alignment state to the bend alignment state of FIG. 9 or 10 has a high energy barrier, and the alignment change may occur at a voltage of about 5 to 7 V which is a general driving condition of liquid crystals. Can not.

As a countermeasure, before the display, a bend alignment is performed by alternately applying a voltage of Vcr (a voltage value at which the bend alignment is more energy stable than the splay alignment) or more and no voltage or a voltage below Vcr. Japanese Patent Laid-Open No. 9-185032 proposes a method for promoting the above-mentioned phenomenon. The method of repeating the voltage application and the voltage non-application is certainly effective for the splay-bend transition, but since the example of this prior art is only the test cell, an actual active matrix liquid crystal including various wiring regions is used. The conditions are different from the display. We have actually confirmed that the bend transition does not occur in all pixels even when the voltage application proposed in the above publication is applied to an active matrix liquid crystal display.

The first reason why the bend transition is not completely performed even if the technique of the above-mentioned publication is applied to an actual active matrix liquid crystal display is that the source voltage is about 0.5V at the lowest and completely 0V. Cannot be set (the pixel potential cannot be set to 0V). In fact, in the test cell experiment, the probability of orientation transition is low unless the pixel potential is completely set to 0V.

Although some source ICs can output an output voltage of 0V, if an output voltage of 0V is to be output, the output voltage can only output 1/2 of the power supply voltage supplied to the IC, so that the gradation voltage can be freely set. Can not.

Next, the second reason will be described with reference to the drawings of an embodiment of the liquid crystal display device according to the present invention. FIG. 1 shows an active matrix liquid crystal display (AML) used in the present invention.
An example of a circuit diagram of the entire CD) is shown. This is a common wiring structure in which a so-called storage capacitor wiring is formed separately from the gate wiring. Here, 101 is a gate wiring for supplying a scanning voltage, 102 is a source wiring for supplying a signal voltage, 103 is a thin film transistor (TFT) used as a switching element when a voltage is applied to liquid crystal, 104
Is a capacitance equivalent to a liquid crystal that performs light transmission / non-transmission switching, 105 is a storage capacitance for reducing the influence of parasitic capacitance of TFTs arranged in parallel with the liquid crystal 104, and 106 is a storage capacitance. Is a common wiring that forms the.
The common wiring is connected to the common wiring lead line 120 via a contact hole. A common voltage is externally applied to the counter electrode on the CF-side substrate via the common wiring terminal 123 connected to the common wiring lead-out line. 109
Reference numeral 107 denotes a connecting portion for connecting one electrode of the liquid crystal 104 to a common voltage. Reference numeral 107 denotes a gate side external circuit on the gate wiring 101.
A gate terminal for connection using CP or the like, and a source terminal 108 for connecting the source side external circuit and the source wiring 102 using TCP or the like. A TFT array is often formed in a shape as shown in FIG. 2 is a plan view of the pixel portion, and FIGS. 3 and 4 are cross-sectional views taken along the alternate long and short dash line in FIG.

FIG. 2 is a plan view of a pixel portion formed on the TFT side substrate side of the active matrix liquid crystal display (AMLCD) used in the present invention, FIG. 3 is a sectional view taken along the line AA of FIG. 2, and FIG. FIG. 6 is a sectional view taken along line BB of FIG. 2 to 4, 201 is an insulating substrate, 202 is a gate electrode and a gate wiring, 203 is a common (holding capacity) wiring, 204
Is a gate insulating film, 205 is a semiconductor layer, 206 is a semiconductor (ohmic contact) layer containing a high concentration of impurities such as P or B, 207 is a source electrode and source wiring, 208 is an insulating protective film, and 209 is a drain electrode. Insulating protective film contact holes for connecting pixel electrodes, 21
Reference numeral 0 is a pixel electrode formed of a transparent conductive layer such as IT0 (Indium Tin Oxide), 211 is a counter electrode formed of a transparent electrode such as ITO on the CF side substrate side, and 212 is a liquid crystal molecule.

3 and 4 show a liquid crystal panel constructed by using a pair of the TFT side substrate and the CF side substrate facing each other in FIG. 21 shows the alignment state of the liquid crystal molecules of the liquid crystal panel filled between the substrates, and 212 shows the liquid crystal molecules. The polyimide resin applied as the alignment film to the inside of the opposing substrate horizontally aligns the liquid crystal molecules when the rubbing treatment is performed, so that the liquid crystal molecules in the electrode portion are horizontally aligned. The alignment of the liquid crystal in FIGS. 3 and 4 shows the case where the rubbing is performed in the direction indicated by the arrow 9 in FIG. 2, that is, the case where the rubbing is performed from the top of the paper surface to the bottom. An alternating voltage of, for example, 7 V is applied between the opposing electrodes of the liquid crystal display device thus configured (for example, the potential of the opposing electrode 211 is 7.2 V and the potential of the pixel electrode 210 is 0.2 V and 14.2).
V) Then, as shown in FIGS. 5 to 6, the liquid crystal molecules try to align at an angle close to the vertical to the substrate due to the effect of the electric field. The voltage of 7V applied to the liquid crystal can be obtained by a normal drive circuit without using a special circuit board by using a source IC that outputs 15V. When a voltage of about 7 V is applied when a voltage is applied, a liquid crystal molecule in the central portion of the panel in the thickness direction has an alignment state that is nearly vertical to a part, and the liquid crystal in one pixel entire region is bend-aligned. And a pixel in which liquid crystal molecules in the central portion in the thickness direction in the panel have an alignment state close to horizontal and a bend alignment is not completely formed coexist. Therefore, when voltage application and no voltage application to the liquid crystal are repeated, the liquid crystal molecules repeat vertical alignment and horizontal alignment. It is described in JP-A-9-185032 that the fluctuation of the liquid crystal molecules effectively acts on the bend transition. However, actually, in the active matrix liquid crystal display, even if voltage application and non-application to the liquid crystal on the pixel electrodes are repeated, it is not possible to cause all pixels to undergo bend transition.

The reason for this is that, in an active matrix liquid crystal display, various wirings occupy a large proportion of one pixel, so that movements of liquid crystal molecules on various wirings cannot be ignored. Even if voltage application and no voltage application to the liquid crystal are repeated on the pixel electrode, the liquid crystal of all pixels in the panel does not undergo bend transition at a voltage of 10 V or less. This is because it is important to completely set the applied voltage to 0 V in the state where no voltage is applied. However, the liquid crystal on each wiring is also applied with a voltage, which is lower than the voltage applied to the liquid crystal on the pixel electrode.
The orientation is as shown in FIGS. 5 to 6, and the transition to the bend orientation is impossible. Taking a general driving and TFT array structure as an example, when a signal voltage is applied to the source wiring with an AC waveform and an insulating protective film such as SiN is present on the source wiring, the signal of the source is turned on when the TFT is in the ON state. Even if the voltage is set to the same potential as the counter substrate, there is a potential difference on the source wiring between the counter substrate and the counter substrate. When the pixel electrode and the electrode of the counter substrate have the same potential when the TFT is in the OFF state, the signal voltage of the source is set higher than that of the pixel electrode by the voltage dropped by field through. Therefore, there is a potential difference between the source wiring and the counter substrate. Thus, even if the voltage applied to the liquid crystal molecules on the pixel electrodes is 0 V, if there is a potential difference between the wiring and the counter substrate, the liquid crystal molecules on the wiring are not in a horizontal alignment and the alignment does not change. Try to orient vertically to the substrate. The same can be said for the gate wiring. TFT for gate wiring
Since a voltage for turning on (about 18 V) and a voltage for turning off (about -5 V) are applied, all the liquid crystal molecules on the gate wiring must be parallel to the substrate as shown in FIG. There is no.

As described above, various wirings (source, gate)
The behavior of the liquid crystal molecules above is significantly different between the active matrix liquid crystal display and the test cell in which the pixel electrodes are evenly present on the entire surface of the substrate. Therefore, the above-mentioned JP-A-9-
As described in Japanese Patent No. 185032, even if a method of repeating voltage application and no voltage application only on a pixel electrode is applied to an active matrix liquid crystal display, the method disclosed in Japanese Patent Laid-Open No.
As described in Japanese Patent No. 185032, the voltage is 6V.
All the pixels could not be bend-transferred within 2 minutes. In the case of no voltage application in the TFT-LCD, 0.3V which is the minimum output voltage of the driver IC is actually applied. FIG. 18 shows the measurement results of the bend transition probability when the voltage is 7.3 V and the voltage application time / voltage non-application time is 5 seconds / 0.5 seconds, respectively. As shown by the curve B in FIG.
When voltage application / non-voltage application is repeated only to the liquid crystal on the pixel electrode, all pixels do not undergo bend transition even if voltage application / voltage non-application is repeated 10 times. It remained at about%.

According to the present invention, the liquid crystal on the wiring can be turned on / off in the same manner as on the pixel electrode to accelerate the bend transition from the splay alignment.
It is an object of the present invention to provide a liquid crystal display device which can effectively obtain bend alignment in a FT-LCD even at a low voltage.

The present invention also provides a general driver IC which cannot completely set the output to 0V or any other driver IC.
It is an object of the present invention to provide a liquid crystal display element using a liquid crystal display element, in which a pixel potential is alternately switched between 0 V and several V, and a bend alignment can be effectively obtained with a TFT-LCD even at a low voltage. And

In the liquid crystal display device of the present invention,
With respect to the liquid crystal display element having the conventional configuration, the bend transition can be generated by partially modifying the power supply circuit and the control circuit without changing the liquid crystal panel and the drive circuit around the liquid crystal panel.

[0017]

The liquid crystal display device of the present invention is an active matrix type liquid crystal display device, and in addition to repeating voltage application and no voltage application only to liquid crystal molecules on pixel electrodes contributing to display, It is characterized in that the liquid crystal molecules on the wiring that do not contribute to the voltage are repeatedly applied with the voltage and not applied with the voltage to initialize the liquid crystal orientation from the sublay orientation to the bend orientation.

Further, the liquid crystal display device of the present invention comprises a pair of substrates having electrodes formed thereon, a liquid crystal material and a polarizing plate sandwiched therebetween, and the rubbing treatment directions on the surfaces of both substrates are substantially parallel to each other. An OCB type liquid crystal display device in which the dielectric anisotropy of the liquid crystal material is positive, the liquid crystal display device is an active type liquid crystal panel using a thin film transistor, and a driver IC for driving the panel is mounted.
It is characterized in that the liquid crystal orientation is initialized by turning on / off the power supply to the driver IC.

According to the present invention, the signal from the control circuit to the source IC sends data for generating the maximum voltage that can be driven,
Turn on the power supply to the source IC and the power supply to the gate IC.
By turning N / OFF, the maximum voltage that can be driven and 0 V can be alternately applied to the pixels of the TFT-LCD. The power supply is turned on and off a plurality of times when the power is supplied to the liquid crystal panel.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of a liquid crystal display device according to the present invention will be described with reference to the drawings. First, FIG. 15 shows a circuit around a normal liquid crystal display panel. A scanning voltage is sent from the gate IC and a data voltage is sent from the source IC to the panel. A power supply and a scanning signal are sent to the gate IC from the power supply circuit and the control circuit, respectively. Like the gate IC, the source IC also receives power and data signals from the power supply circuit and the control circuit, respectively. Normally, power is constantly sent from the power supply circuit to each of the gate IC and the source IC regardless of whether or not a data signal is transmitted.
In the first embodiment of the present invention, as shown in FIG.
By inserting an ON / OFF switching element in the power supply line from the power supply circuit to the gate IC and the source IC, the power supply can be cut off. As a result, the data signal voltage from the source IC can be set to 0V, and the scanning voltage from the gate IC can be set to 0V.

FIG. 17 is a configuration diagram of the second embodiment.
O in the middle of the power supply line from the power supply circuit to the gate IC
Line and T that supply normal power, not N / OFF
A circuit of a line for supplying another power source is formed so that the leak current of the FT can be adjusted. It is possible to instantly discharge the electric charge accumulated in the pixel regardless of the characteristics of the TFT. By changing these circuits, it becomes possible to repeat application and non-application of voltage to the liquid crystal on various wirings, and to promote bend transition for all pixels of the active matrix liquid crystal display.
It is possible to reduce the bend transition voltage.

Embodiment 1 The structure of a liquid crystal display element according to the present invention will be described with reference to the drawings. FIG. 16 is a block diagram of a liquid crystal display device according to the present invention. A switching element for turning ON / OFF is provided in a supply line from the power supply circuit to the source side external circuit board on which the source IC and the gate IC are arranged and the supply line to the gate side external circuit board. With this configuration, the applied voltage can be completely set to 0V not only on the pixel electrodes but also on all the electrode wirings. The structure in the panel of FIG. 16 is a conventional structure as shown in FIG. The gate terminal of 107 and the gate side external circuit are connected using TCP or the like. Further, the source terminal of 108 and the source side external circuit are connected using TCP or the like. This is the configuration of the liquid crystal display element according to the present invention, the liquid crystal panel and the drive circuit around the liquid crystal panel are the same as those of the conventional liquid crystal display element, and only a part of the power supply circuit is changed. In such a configuration, the bend transition rate of all pixels in the panel can be greatly improved by the timing of turning on / off the signal from the power supply circuit to the panel.

The reason why the voltage is not applied is to reset the orientation of the liquid crystal molecules which could not undergo the splay → bend transition even when the voltage is applied, to the splay orientation in the initial state. Therefore, in the state where no voltage is applied, it is sufficient that the liquid crystal instantaneously creates an alignment at 0V. At that time, the pixel that succeeded in the splay → bend transition does not immediately return to the splay alignment even if no voltage is applied, but returns to the splay alignment through the twist-splay alignment disclination, and thus once bend-aligned. The area remains as a twist area for some time. If all the liquid crystals in one pixel have completely returned to the splay orientation, the splay will be applied even if a new voltage is applied.
Since there is no guarantee of bend transition, it is necessary to apply voltage again before the orientation of the bend-oriented region returns to the splay orientation. In this way, if the alignment state of the bend-aligned region is not preserved, it is impossible to shorten the time until the transition from the break to bend in all the pixels in the panel. Therefore, the optimum voltage non-application time is set to be longer than the time for the liquid crystal alignment of the pixels that have not undergone bend transition to return to the initial state, and shorter than the time for the liquid crystal of the bend transition pixels to return to splay alignment. There is a need. Therefore, the voltage non-application time may be determined by the following two points. That is, the return time of the pixel electrode to 0V due to the source-drain current value when the TFT is OFF, and the response time of the liquid crystal (time required to return from the splay state when voltage is applied to the splay state when no voltage is applied). There are two points. By setting such voltage non-application time,
Even when the voltage applied between the electrodes is about 7 V, the bend alignment can be obtained in all the pixels in the panel by repeating the voltage application and the voltage non-application several times.

FIG. 13 shows the AMLCD TF used in the present invention.
It is an Id-Vg characteristic view of a T element. The pixel electrode discharges the electric charge stored in the pixel through the TFT. When the charge stored in one pixel is 0.2 pC (pico coulomb), the time required to discharge the charge is, for example, as shown in FIG.
In the case of the TFT characteristics (Id-Vg) as shown in Fig. 5, the source voltage when the gate voltage is 0V and the source-drain voltage is 5V
The drain current is about 50 pA (picoampere). Since the source / drain voltage decreases in proportion to the discharge of the electric charge of the pixel, 4
It takes more than msec. After that, the liquid crystal molecules change the orientation to the parallel orientation of the substrate which is the initial orientation according to the voltage change. The time required for this depends on the viscosity coefficient of the liquid crystal molecules. The optimum value of the voltage non-application time in the panel performed by us is 0.5 to 1.0 second. A panel having a diagonal length of 15.0 inches and the number of pixels (768 × 1024) was applied with a drive circuit shown in FIG.
Voltage application (7V) and no voltage application (0V) with time setting of 5 seconds
FIG. 18 shows the bend transition rate measurement results when V) is repeated.
Is shown by the curve A. The number of times the horizontal axis of FIG. 18 is turned ON is counted as the first time even when the panel is powered on. 20% of the pixels in the panel have undergone bend transition even if the power of the panel is turned on. When ON / OFF is repeated three more times, 90% of pixels in the panel undergo bend transition. 10
To make 0% bend transition, turn on / off three more times.
It is necessary to repeat OFF, and ON / OFF needs to be performed 6 times in total, and in time, the spray → bend transition of all pixels in the panel can be completed in about 35 seconds after the panel is turned ON. The cell gab of the panel at that time is 5μ
m, the pretilt angle is 5 degrees. If the cell gab is made narrower than this, the bend transition time will be further shortened.

Second Embodiment Next, a second embodiment of the present invention will be described.
Consider a case where the Id-Vg characteristic of the TFT element of the AMLCD shifts to a higher voltage side than that of FIG. 13 as shown in FIG. When the charge stored in one pixel via the TFT is 0.2 pC, the time required to discharge the charge is 0V when the gate voltage is 0V. Since the source / drain current is about 1 pA when the source / drain voltage = 5 V, it requires at least 200 msec.
If the voltage non-application time is long, the bend-aligned liquid crystal returns to the splay alignment, and as a result, the bend transition time becomes long. Therefore, the signal from the power supply circuit
If the source / drain current immediately after FF (immediately after no voltage is applied) is 10 pA or more, the method of accelerating the bend transition by applying or not applying a voltage is not effective. By making the gate voltage variable when no voltage is applied, it is possible to set the source / drain current to 10 pA or more immediately after no voltage is applied, even when the TFT characteristics are shifted. In the second embodiment, a circuit (leakage power supply) that releases the charge of the pixel electrode in a short time is incorporated.
A schematic diagram of the configuration is shown in FIG. Id as shown in FIG.
In a TFT having a −Vg characteristic, the source immediately after the signal from the power supply circuit is turned off (immediately after no voltage is applied).
In order to make the drain current 10 pA or more, it is necessary to set the gate voltage to 3V. In order to realize it, it suffices to set the leakage power source to 3V.

[0026]

As described above, according to the present invention,
By repeating voltage application and no voltage application to the liquid crystal molecules on the pixel electrodes and voltage application and no voltage application to the liquid crystal molecules on the wiring, the alignment state of the liquid crystal molecules is efficiently transferred from splay alignment to bend alignment. Can be made.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an entire active matrix liquid crystal display according to the present invention.

FIG. 2 is a plan view of a pixel portion formed on a TFT side substrate.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a sectional view taken along line BB in FIG.

5 is a diagram showing an arrangement of liquid crystal molecules when an AC voltage is applied to the pixel unit shown in FIG.

6 is a diagram showing an arrangement of liquid crystal molecules when an AC voltage is applied to the pixel portion shown in FIG.

7 is a diagram showing an arrangement of liquid crystal molecules when there is a potential difference in the pixel portion shown in FIG.

8 is a diagram showing an arrangement of liquid crystal molecules when there is a potential difference in the pixel portion shown in FIG.

FIG. 9 is an explanatory diagram of liquid crystal alignment (bend alignment).

FIG. 10 is an explanatory diagram of liquid crystal alignment (for bending).

FIG. 11 is an explanatory diagram of liquid crystal alignment (spray alignment).

FIG. 12 is an explanatory diagram of liquid crystal alignment (asymmetric splay alignment).

FIG. 13 is a TFT characteristic diagram (Id-Vg).

FIG. 14 is a TFT characteristic diagram (Id-Vg).

FIG. 15 is a circuit configuration diagram around a normal liquid crystal display panel.

FIG. 16 is a circuit configuration diagram around a liquid crystal display panel that is Embodiment 1 of the present invention.

FIG. 17 is a circuit configuration diagram around a liquid crystal display panel which is Embodiment 2 of the present invention.

FIG. 18 shows the results of bend transition rate measurement on a TFT-LCD.

[Explanation of symbols]

9 arrow (rubbing direction) 101 gate wiring 102 source wiring 103 TFT 104 Liquid crystal (capacity) 105 holding capacity 106 common wiring 107 Gate terminal 108 Source terminal 109 connection 120 common wiring leader line 201 Insulating substrate 202 Gate electrode / wiring 203 common wiring 204 gate insulating film 205 semiconductor layer 206 Ohmic contact layer 207 Source electrode / wiring 208 Insulation protection film 209 contact holes 210 pixel electrode 211 Counter electrode 212 liquid crystal molecule

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tetsuya Ikemoto             997 Miyoshi, Nishigoshi-cho, Kikuchi-gun, Kumamoto             Ceremony Company Advanced Display F-term (reference) 2H088 EA02 GA02 HA02 HA08 JA04                       KA26 MA20                 2H092 GA59 JA24 NA25 PA06 QA06                 2H093 NA16 NC34 NC35 ND60 NE04                       NF04 NH04

Claims (4)

[Claims] 1. In an active matrix liquid crystal display device, voltage application and voltage non-application are repeated on liquid crystal molecules on pixel electrodes contributing to display, and voltage application and voltage imprinting are also applied to liquid crystal molecules on wiring not contributing to display. A liquid crystal display device characterized in that liquid crystal alignment is initialized from splay alignment to bend alignment by repeating addition. 2. A pair of substrates on which electrodes are formed and a liquid crystal material and a polarizing plate sandwiched between the substrates are provided, the rubbing directions of the surfaces of both substrates are substantially parallel to each other, and the dielectric constant anisotropy of the liquid crystal material used. Is an OCB type liquid crystal display element, the liquid crystal display element is an active type liquid crystal panel using a thin film transistor, and a driver IC for driving the panel is mounted, and a power supply to the driver IC is provided. A liquid crystal display device characterized in that the liquid crystal alignment is initialized by turning on and off. 3. The liquid crystal orientation is controlled by turning on / off the power supply to the driver IC in a state where data for outputting a voltage equal to or higher than a voltage capable of maintaining the orientation of the OCB type liquid crystal is input to the driver IC. Claim 2 which initializes
The liquid crystal display element described. 4. The power supply to the source driver IC is turned on and off, and the gate driver IC is switched to a specified power supply and a voltage such that a leak current of a thin film transistor of a liquid crystal panel used is 10 pA or more. The liquid crystal display element according to claim 2 or 3, wherein the liquid crystal alignment is initialized by means of.