JP2002014320A - Method for driving liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for driving a liquid crystal display device realizing a high quality display by suppressing crosstalk deteriorating picture quality as much as possible. SOLUTION: In the liquid crystal display device provided with an array substrate having plural scanning lines formed on a 1st transparent substrate, plural signal lines formed on the 1st transparent substrate so as to cross these scanning lines, pixel electrodes formed at each cross point of the scanning lines and the signal lines, and switching elements which are arranged correspondingly to respective pixel electrodes; which are switched on-off by corresponding scanning line voltages; and which send picture signals from the corresponding signal lines to the corresponding pixel electrodes, a counter substrate having counter electrodes formed on a 2nd transparent substrate, and a liquid crystal layer consisting of a mono-stable ferroelectric liquid crystal material held in a gap between the array substrate and the counter substrate, picture signals to be sent to pixels corresponding to the scanned scanning line during the scanning period of the scanning lines, and correction signals correlated to have the reverse polarity to these picture signals and have the same absolute value as this picture signal are applied to the signal lines corresponding to the pixels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for driving a liquid crystal display device.

[0002]

2. Description of the Related Art There is a problem that a liquid crystal material is deteriorated when a direct current is continuously applied due to the characteristics of the material itself. Therefore, in order to drive the liquid crystal, it is necessary to apply an AC voltage. As an example of a method of applying an AC voltage, there is a frame inversion driving method in which a counter electrode is shaken for each frame in accordance with the polarity of a voltage to be written (see JP-A-55-28649). However, in the frame inversion driving method, depending on an image, crosstalk is likely to occur due to a voltage change during the holding period. FIG. 8 shows signal waveforms when displaying an image in which 4 × 4 pixels are displayed in black as shown in FIG. 4 by the frame inversion driving method in which the common applied voltage is inverted. It is conceivable that the cause of the fluctuation of the holding voltage is the influence of the applied signal via the parasitic capacitance between the pixel and the wiring. 8A is a voltage waveform of a scanning signal applied to a scanning line to which a pixel A is connected, FIG. 8B is a voltage waveform diagram of a scanning signal applied to a scanning line to which a pixel B is connected, and FIG.
8C shows a voltage waveform of an image signal applied to a signal line connected to the pixel A, FIG. 8D shows a voltage waveform applied to a counter electrode of the pixel A, and FIG. FIG. 8F shows the voltage waveform applied to the liquid crystal and the transmittance of the pixel A. As shown in FIG. 8E, the voltage applied to the liquid crystal of the pixel A varies according to the voltage waveform applied to the signal line, and the effective voltage applied to the liquid crystal varies according to the image to be displayed. For this reason, as shown in FIG. 8F, the effective value of the transmittance of the pixel also varies depending on the displayed image, and crosstalk occurs. Particularly in recent years, there has been a strong demand for higher definition, and the distance between the pixel and the wiring has been reduced. For this reason, crosstalk tends to occur.

Further, an LCD (Liquid Crystal) is used.
al Device) is liable to cause blurring or jaggies of the outline of an image when a moving image is displayed. The cause is that the image of the current frame and the image of the next frame are almost simultaneously observed when the current frame and the next frame are rewritten. The LCD is, in principle, a hold-type display device having a memory function of maintaining the state of a pixel (transmission state) until the next field and continuing to emit light. In contrast, CRT (CathodeRay T)
ube) is an impulse-type display device that emits light only once in one field. The hold-type display device has a longer light emission time than the impulse-type display device, and therefore, when a moving image is displayed, the outline of the image is easily blurred or jagged.

[0004]

Further, it is widely known that ferroelectric liquid crystals have hysteresis characteristics. As a method of canceling the influence of the hysteresis and performing halftone display, a method of applying a reset pulse is known (see JP-A-2000-19485).
In this method, a reset pulse having a correlation with the image signal applied to the previous frame is applied. However, this method has a problem that the effect of reducing the crosstalk is extremely low and the image quality deteriorates.

The present invention has been made in view of the above circumstances, and provides a driving method of a liquid crystal display device capable of suppressing a crosstalk which causes image quality deterioration as much as possible and enabling high image quality display. The purpose is to:

[0006]

According to the present invention, there is provided a method of driving a liquid crystal display device, comprising: a plurality of scanning lines formed on a first transparent substrate; and a plurality of scanning lines formed on the first transparent substrate so as to intersect these scanning lines. A plurality of signal lines, pixel electrodes formed at the intersections of these scanning lines and signal lines, and corresponding signal lines which are opened and closed by the voltages of the corresponding scanning lines provided corresponding to the respective pixel electrodes. A switching element that sends an image signal from the corresponding pixel electrode, and an array substrate having
A liquid crystal display comprising: a counter substrate having a counter electrode formed on a second transparent substrate; and a liquid crystal layer made of a monostable ferroelectric liquid crystal material interposed between the array substrate and the counter substrate. In the apparatus, during a scanning period of the scanning line,
An image signal to be sent to a pixel corresponding to the scanned scanning line and a correction signal having a polarity opposite to that of the image signal and having a correlation so that an absolute value is equal are applied to a signal line corresponding to the pixel. It is characterized by the following.

According to the driving method of the liquid crystal display device according to the present invention, the image signal to be sent to the pixel corresponding to the scanned scanning line and the polarity of the image signal and the voltage are reversed. Is applied to a signal line corresponding to the pixel during the scanning period of the scanning line. As a result, it is possible to prevent image quality deterioration due to crosstalk as much as possible, and a high-quality image can be displayed.

[0008] The correction signal may be applied immediately before or immediately after an image signal having a correlation with the correction signal.

The correction signal may be applied a plurality of times during one frame.

[0010] The product of the absolute value of the value of the correction signal and the application time may be equal to the product of the absolute value of the voltage of the image signal and the application time.

The scanning signal applied to the scanning line is:
There may be a configuration in which a writing period and a non-writing period having the same length as the writing time are provided, an image signal is applied to the signal line during the writing period, and the correction signal is applied during the non-writing period. .

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings, but the present invention is not limited to these embodiments.

(First Embodiment) Before describing a method of driving a liquid crystal display device according to the present invention, a liquid crystal display device will be described. FIG. 2 shows a general configuration of a liquid crystal display device. The liquid crystal display device includes a liquid crystal display panel 20, a scanning line driving circuit 30, a signal line driving circuit 40, and a memory 50.
And The liquid crystal display panel 20 includes an array substrate, a counter substrate, and a liquid crystal material layer sandwiched between the array substrate and the counter substrate. The array substrate includes a plurality of scanning lines 22 formed on a transparent substrate.
And a plurality of signal lines 23 arranged so as to intersect these scanning lines, and a switching element 21 and a pixel electrode 24 provided at each intersection of the scanning lines and the signal lines.
And The switching element 21 is, for example, a TFT (Thin Film Transistor).
r), the gate electrode of the TFT 21 is connected to the corresponding scanning line 22, the source electrode is connected to the corresponding signal line 23, and the drain electrode is connected to the pixel electrode 24, respectively. Thereby, the switching element is turned on by the scanning line 22.
The signal voltage is supplied to the pixel electrode to which the gate voltage that makes the state is applied. The scanning line drive circuit 30 sequentially selects and drives the scanning lines based on a control signal. The signal line drive circuit 40 selects a signal line based on the control signal, and sends out an image signal read from the memory 50 to the selected signal line. The memory 50 has a plurality of memory cells, writes an image signal into a memory cell corresponding to the address signal based on a control signal (address signal), and writes the written image signal into the memory cell based on the control signal. The signal is sent from the cell to the signal line drive circuit. The counter substrate has a counter electrode formed on a transparent substrate. The array substrate and the counter substrate are arranged in a predetermined gap such that the counter electrode and the pixel electrode face each other, and the liquid crystal material layer is sealed in the gap.

The liquid crystal layer used in the liquid crystal display device to which the driving method according to the present invention is applied is appropriately set with a liquid crystal material and an element configuration, and is in a first alignment state when no voltage is applied. When a voltage of the first polarity is applied to the liquid crystal layer, the liquid crystal molecules tilt from the first alignment state to the second alignment state and the second
Further, when a voltage having a polarity opposite to the first polarity is applied to the liquid crystal layer, the liquid crystal molecules tilt from the first alignment state to the third alignment state, and the third transmittance And the second transmittance and the third transmittance according to the value of the applied voltage.
A material exhibiting a voltage-transmittance characteristic in which the transmittance continuously changes between the transmittance and the transmittance is used. Specifically, a monostable ferroelectric liquid crystal material is preferably used.

FIG. 3 shows a voltage-transmittance characteristic of the liquid crystal display panel used in the driving method of the present invention. When no voltage is applied, the molecular axis coincides with the uniaxial orientation processing direction (for example, rubbing direction). When a positive voltage is applied, the molecules shift on the cone according to the magnitude of the applied voltage. When a negative voltage is applied, the molecule is uniaxial. It stays in the orientation direction. Here, when the refractive index anisotropy of the liquid crystal layer is Δn, the cell pressure is d, and the product Δn · d is set to 波長 wavelength, the opening angle of the molecule becomes 4
The maximum brightness is obtained at 5 °. In order to form these alignment states, the liquid crystal display panel is heated to 80 ° C. or higher, and then a DC voltage of −1 to −5 V (forming the first alignment state) is applied between the electrodes while the liquid crystal display panel is near 50 ° C. Cool down to

Further, as a liquid crystal panel having the same characteristics,
After heating the photocured liquid crystalline (meth) acrylate and the content of ferroelectric liquid crystal to about 80 ° C., −1 to −5 V (forms a first alignment state) or 1 to 5 V (second alignment state) Is formed while applying a DC voltage of 365 nm.
There is also a polymer-stabilized ferroelectric liquid crystal which is irradiated with ultraviolet rays for 30 seconds. However, in this case, since the cone of the liquid crystal is formed around the rubbing axis, it is not sufficient to change the polarizing axis of the polarizing plate according to the alignment region or to adjust the rubbing direction to the polarizing axis of the polarizing plate. No contrast can be obtained. This cell orientation method is well known (see JP-A-1-326906), so further description is omitted, but the present invention is applied to a liquid crystal display device using a polymer-stabilized ferroelectric liquid crystal for a liquid crystal layer. By applying the above driving method, it is possible to improve the image quality of a moving image.

A first embodiment of the method for driving a liquid crystal display device according to the present invention will be described. As shown in FIG.
FIG. 1 shows a timing chart when displaying an image in which × 4 pixels are displayed in black. FIG. 1A shows a voltage waveform of a scanning signal applied to the scanning line to which the pixel A is connected.
FIG. 1B shows a voltage waveform of a scanning signal applied to the scanning line to which the pixel B is connected, FIG. 1C shows a voltage waveform of an image signal applied to the signal line to which the pixel A is connected, and FIG. 1 shows a voltage waveform applied to the counter electrode of the pixel A, FIG. 1E shows a voltage waveform applied to the liquid crystal of the pixel A, and FIG. 1F shows transmittance of the pixel.

As shown in FIG. 1, in the present embodiment, one frame period is divided into a first frame period F1 and a second frame period F2, an image is displayed in the first frame period F1, and a second frame period is displayed. In the period F2, black is displayed. First, the first frame period F1
Is divided into a first writing period TW1 and a second writing period TW2. In the first writing period TW1, the absolute value of the voltage value is the same as that of the image signal applied in the second writing period TW2 and the polarity is opposite. A polarity correction signal is applied, and an image signal is applied in the second writing period TW2. Further, during the first writing period TW3 of the scanning selection period T3 of the second frame period F2, the first frame F
1 in the second writing period TW2, and the correction signal applied in the first writing period TW1 of the first frame F1 during the second writing period TW4 of the scanning selection period T3 of the second frame period F2. Apply. By these operations, it is possible to display a moving image without blurring or jaggies of the outline of the image, and to reduce the average value of the fluctuation of the transmittance of the liquid crystal to zero, thereby displaying an image without crosstalk.

This will be described with reference to FIG. 5 in which a part of FIG. 1 is enlarged. FIGS. 5 (a), (c), (e) and (f)
It is the figure which expanded Drawing 1 (a), (c), (e), and (f), respectively. Scan selection period T1 in first frame period F1
, The switching element connected to the pixel is ON
State (see FIG. 5A). At this time, in the first writing period TW1, the voltage of the liquid crystal of the pixel is equal to -Vcmp when the correction signal voltage applied to the signal line is written.
(See FIG. 5E). Further, in the second writing period TW2, the voltage of the liquid crystal of the pixel becomes + Vsig by writing the image signal voltage applied to the signal line (see FIG. 5C). Next, in the non-selection period T2,
The voltage of the liquid crystal of the pixel is ideally + Vsig, but actually fluctuates due to the capacitance between the pixel and the wiring.
Therefore, assuming that the amount of change in the voltage of the pixel during the first writing period TW3 is −ΔVsig × TW3, the voltage of the liquid crystal of the pixel is + Vsig−ΔVsig × TW3. Also in the second writing period TW4 of the non-selection period T2, the voltage of the liquid crystal of the pixel varies due to the capacitance between the pixel and the wiring. The amount of change in the voltage of the liquid crystal of the pixel is + ΔVcm
Assuming that p × TW4, the voltage of the liquid crystal of the pixel is Vsig
−ΔVsig × TW3 + ΔVcmp × TW4. Here, the amount of change in voltage that occurs when an image signal is applied in the first writing period TW3 of the non-selection period T2−ΔV
The voltage value of the correction signal Vcmp is set so that sig × TW3 can be corrected by the amount of voltage fluctuation + ΔVcmp × TW4 that occurs when the correction signal is applied in the second writing period TW4 of the non-selection period T2. That is, the voltage value of Vcmp is set so that ΔVsig × TW3 = ΔVcmp × TW4 (1). As a result, the effective fluctuation amount of the voltage during the holding period becomes zero, and the effective luminance of the display image does not change due to the capacitance between the pixel and the wiring, but is caused by the parasitic capacitance between the pixel and the wiring. The uneven luminance of the screen due to the raw capacitance crosstalk is reduced by applying the correction signal, and a high-quality display is possible.

Equation (1) shows that the same amount of change as the change in the voltage of the image signal applied to the signal line may be given. That is, the correction signal has the same absolute value as the image signal, and the polarity may be reversed.

The generation of the correction signal will be described with reference to FIG. FIG. 11 is a timing chart of input / output signals of the memory 50 and the signal line driving circuit 40. First,
The image signal is input to the memory 50 in a cycle of the scanning selection period T1. Then, from the memory 50, the scanning selection period T
In order to apply the correction signal and the image signal to the signal line 23, the same image signal is output for the length of the first writing period TW1 and the length of the second writing period TW2, respectively. The signal line drive circuit 40 sets the POL signal to “H” and outputs the positive signal while controlling the polarity inversion signal (POL), which is one of the control signals, while outputting the negative signal. When outputting, the POL signal is set to “L”, the polarity of the output signal of the signal line driving circuit 40 is inverted, a correction signal and an image signal are generated and applied to the signal line.

By the above operation, a high-quality image without crosstalk can be displayed in the first frame. Further, by applying a voltage having a polarity opposite to the voltage applied to the liquid crystal in the first frame in the second frame, the bias of the charge of the liquid crystal material is prevented, and a moving image is displayed by displaying a black image. Display a high-quality image with less outline blurring and jaggies.

Specifically, the polarity of the voltage applied to the common electrode in the second frame is inverted. If it is a bistable liquid crystal material, even if a negative voltage is applied to the liquid crystal,
As in the case where a positive voltage is applied, the transmittance changes according to the voltage value. However, in the monostable liquid crystal material used in the present invention, when a negative voltage is applied to the liquid crystal,
The transmittance is almost zero (see FIG. 3). Therefore, the image displayed between the second frames is black. By displaying this black, the light emission time is shortened, and when displaying a moving image, blurring of the outline of the image, jaggies and the like are less likely to occur.

In the present embodiment, a case where one image display period and one black display period are included in one frame period is described as an example, but the present invention is not limited to this. Alternatively, the present invention can be applied to a case where one frame period includes one display period and a plurality of black display periods, such as a case where one frame period has one display period and two black display periods.

When displaying a still image, it is possible to display an image over a plurality of frames and display a black image over the same number of frames as the image is displayed. It is desirable to display an image and black for each frame.

(Second Embodiment) A second embodiment of the method for driving a liquid crystal display device according to the present invention will be described with reference to FIG. FIG. 6 is a timing chart when the image shown in FIG. 4 is displayed by the driving method according to the present embodiment. 6A is a voltage waveform of a scanning signal applied to the scanning line to which the pixel A is connected, FIG. 6B is a voltage waveform of a scanning signal applied to the scanning line to which the pixel B is connected, and FIG. ) Is the voltage waveform of the image signal applied to the signal line to which the pixel A is connected, FIG. 6D is the voltage waveform applied to the counter electrode of the pixel A, and FIG. FIG. 6F is a timing chart showing the transmittance of the pixel.

As shown in FIG. 6, the driving method of the present embodiment differs from the driving method of the first embodiment shown in FIG.
The voltage applied to the counter electrode of the pixel A is -Vcom in the first frame period F1, and Vc in the second frame period F2.
Except for om, the liquid crystal display device is similarly driven. In the first embodiment, the voltage applied to the counter electrode of the pixel A is a constant voltage Vcom in the first and second frame periods.

As can be seen from FIG. 6 (e), since the voltage applied to the liquid crystal of the pixel A does not fluctuate effectively, even if the polarity of the counter electrode is reversed as in this embodiment. In addition, capacitive crosstalk can be suppressed. In addition, by inverting the polarity of the counter electrode, a voltage that can be applied to the liquid crystal can be increased, and a clear image with higher contrast can be displayed.

(Third Embodiment) Next, a third embodiment of the method of driving a liquid crystal display device according to the present invention will be described with reference to FIG. FIG. 7 is a timing chart when the image shown in FIG. 4 is displayed by the driving method according to the present embodiment. 7A shows a voltage waveform of a scanning signal applied to a scanning line to which a pixel A is connected, FIG. 7B shows a voltage waveform of a scanning signal applied to a scanning line to which a pixel B is connected, and FIG. )
Is a voltage waveform of an image signal applied to the signal line to which the pixel A is connected, FIG. 7D is a voltage waveform applied to the counter electrode of the pixel A, and FIG. FIG. 7F is a timing chart showing the transmittance of the pixel.

In this embodiment, as shown in FIG. 7, one frame period is divided into a first frame period F1 and a second frame period F2, an image is displayed in the first frame period F1, and the second frame period is displayed. In the period F2, black is displayed. Further, each scanning selection period of the first frame period F1 and each scanning selection period of the second frame period F2 are divided into first and second writing periods, respectively. For example, the first scanning selection period T1 of the first frame period F1 is divided into a first writing period TW1 and a second writing period TW2, and the second scanning selection period of the first frame period F1 is divided into the first writing period TW3 and the second writing period TW3. Write period TW
Divide into four. Further, the scanning selection period T3 of the second frame period F2 is divided into a first writing period TW5 and a second writing period TW6.

In this embodiment, the writing period TW1 and the writing period TW4 are deselected, and the signals applied to the signal lines in the periods T1, T2, T3, and T4 are corrected signals and image signals. , Image signal, and correction signal. As a result, the frequency of the applied signal can be reduced to achieve low power consumption.

More specifically, a pair of an image signal and a correction signal corresponding to the image signal is referred to as a signal group I for "applying a correction signal after applying an image signal" and a signal group I for applying an image signal after applying a correction signal. "Create signal group II and apply it alternately. As a result, the frequency of the signal applied to the signal line is reduced, and power consumption is reduced. In the present embodiment shown in FIG. 7, the image signal vibrates ten times during one frame (see FIG. 7C), whereas in the first embodiment shown in FIG. The image signal vibrates 14 times (FIG. 1).
(C)). As a result, low power consumption can be achieved.

FIG. 9 is a timing chart of control signals and outputs of a scanning line driving circuit for selecting a scanning period as in the first and second embodiments, and FIG. 10 is a timing chart of the third embodiment. An example of a timing chart of a control signal and output of the scanning line driver circuit in a case where the periods TW1 and TW4 are non-selection periods and the periods TW2 and TW3 are selection periods is shown. 9 and 10, the logical product of a pulse (not shown) having a width equal to one cycle of the clock signal CLK, which is sequentially generated in synchronization with the rise of the clock signal CLK, and an inverted signal of the output control signal OE. Are outputs OUT1, OUT2, O from the scanning line driving circuit to the scanning lines.
These are sequentially output as UT3 and OUT4. Only by changing the output control signal OE, outputs OUT1 and OUT to each scanning line
2, OUT3 and OUT4 can be changed. 9 and 10, a signal STV indicates a synchronization signal. In this manner, the scanning line driving signals of the first to third embodiments can be generated.

In the above embodiment, the case where one image display period and one black display period are included in one frame period is described as an example, but the present invention is not limited to this. However, the present invention can be applied to a case where one frame period includes one display period and a plurality of black display periods, such as a case where one frame period includes one display period and two black display periods.

When displaying a still image, it is not a problem if the image is displayed over a plurality of frames and the black image is displayed over the same number of frames as the image is displayed. It is desirable to display an image and black for each frame.

[0036]

According to the present invention, by applying an image signal and a correction signal having the same absolute value of the voltage value and the opposite polarity to the image signal during the scanning period to the signal line, the capacitance of the image signal is reduced. A high-quality image can be displayed without causing image quality deterioration due to cross stroke.

[Brief description of the drawings]

FIG. 1 is a timing chart of driving waveforms according to a first embodiment of a driving method of a liquid crystal display device according to the present invention.

FIG. 2 is a block diagram illustrating a general configuration of a liquid crystal display device.

FIG. 3 is a graph showing voltage-transmittance characteristics of a liquid crystal using the driving method of the present invention.

FIG. 4 is a diagram showing an example of a display image.

5 is a timing chart in which a part of the driving waveform shown in FIG. 1 is enlarged.

FIG. 6 is a timing chart of driving waveforms according to the second embodiment of the present invention.

FIG. 7 is a timing chart of a driving waveform according to the third embodiment of the present invention.

FIG. 8 is a timing chart of driving waveforms for explaining crosstalk which is a problem in the conventional frame inversion driving method.

FIG. 9 is a timing chart of an output waveform of a scanning line according to the first and second embodiments of the present invention.

FIG. 10 is a timing chart of an output waveform of a scanning line according to the third embodiment of the present invention.

FIG. 11 is a timing chart illustrating generation of a correction signal according to the present invention.

[Explanation of symbols]

 Reference Signs List 20 liquid crystal display panel 21 switching element (TFT) 22 scanning line 23 signal line 24 pixel electrode 30 scanning line driving circuit 40 signal line driving circuit 50 memory

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09G 3/20 621 G09G 3/36 623 G02F 1/136 500 3/36 1/137 510 (72) Inventor Takeshi Ito 1 Toshiba-cho, Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture (72) Inventor Masahiro Baba Inventor Masahiro Baba 1 Toshiba-cho, Komukai-Toshiba-cho, Saiku-ku, Kawasaki-shi, Kanagawa Pref. F-term (reference) 2H088 JA17 KA14 MA02 MA06 2H092 JA24 JB22 JB31 NA01 NA23 PA06 2H093 NA15 NA43 NC09 NC11 NC16 NC29 NC34 NC62 ND39 NF17 5C006 AC11 AC21 AC28 AF44 AF46 BB15 BF02 FA22 FA36 5C080 JJ10 JJ05 BB05 DD11

Claims (5)

[Claims] A plurality of scanning lines formed on the first transparent substrate; a plurality of signal lines formed on the first transparent substrate so as to intersect the scanning lines; A pixel electrode formed at each intersection of signal lines, and a switching element provided corresponding to each pixel electrode and opened and closed by a voltage of a corresponding scanning line and transmitting an image signal from the corresponding signal line to the corresponding pixel electrode. And a counter substrate having a counter electrode formed on a second transparent substrate; and a liquid crystal layer made of a monostable ferroelectric liquid crystal material sandwiched in a gap between the array substrate and the counter substrate. And a liquid crystal display device comprising: during a scanning period of the scanning line, an image signal to be sent to a pixel corresponding to the scanned scanning line, and the polarity of the image signal is opposite to that of the image signal and the absolute value is equal. Correlated to A method for driving a liquid crystal display device, comprising applying a correction signal to a signal line corresponding to the pixel. 2. The method according to claim 1, wherein the correction signal is applied immediately before or immediately after an image signal having a correlation with the correction signal. 3. The method according to claim 1, wherein the correction signal is applied a plurality of times during one frame. 4. The apparatus according to claim 1, wherein the product of the absolute value of the correction signal and the application time is equal to the product of the absolute value of the image signal and the application time. 3. The method for driving a liquid crystal display device according to item 2. 5. A scanning signal applied to the scanning line has a writing period and a non-writing period having the same length as the writing time, and an image signal is applied to the signal line during the writing period. 3. The method according to claim 2, wherein the correction signal is applied during a period.