JPH10333119A - Method and device for driving antiferroelectric liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a driving method by which cross talk is reduced by suppressing the change of a threshold characteristic caused by a difference in a display pattern by inverting the polarities of voltage applied to a scanning electrode and that applied to a signal electrode every time the duty driving of m electrodes is performed and n scanning electrodes are selected. SOLUTION: A substrate 1 having plural scanning electrodes(transparent electrodes 4) and the substrate 2 having plural signal electrodes(the transparent electrodes 5) are arranged at an antiferroelectric liquid crystal element so as to make the transparent electrodes 4 and the transparent electrodes 5 opposed to each other. Antiferroelectric liquid crystal 6 showing one orientation state performing phase transition to ferroelectric liquid crystal showing two orientation states by the polarity of the voltage is held between the substrates 1 and 2. At this liquid crystal element, every time the duty driving of m electrodes((m) is a natural number, >=2) is performed and n scanning electrodes is different, from m and is the natural number whose quotient obtained by dividing a least common multiple with m by n is an odd number) are selected, the polarities of the voltage applied to the scanning electrode and that applied to the signal electrode are inverted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for driving an antiferroelectric liquid crystal element utilizing switching between three stable states of an antiferroelectric liquid crystal which causes a phase transition to a ferroelectric liquid crystal by an electric field. .

[0002]

2. Description of the Related Art Switching between three states of an antiferroelectric liquid crystal is expected as one of methods for solving some essential problems found in a conventional surface stabilized ferroelectric liquid crystal (SSFLC). Active research is ongoing (for example,
ADLChandani et.al .: Jpn.J.Appl.Phys., 27, L7
29 (1988), ADLChandani et.al .: Jpn. J. Appl. Ph.
ys., 28, L1265 (1988), N. Yamamoto et. al .: The 58th Joint Research Meeting of the 142nd Committee of Organic Materials for Information Science, Japan Society for the Promotion of Science, P7-12, (1993), etc.).

The features of the three-state switching include the following (1) to (4). (1) The antiferroelectric-ferroelectric phase transition due to the application of a voltage has a steep threshold characteristic with respect to a DC voltage (see FIG. 8).

(2) Since the antiferroelectric-ferroelectric phase transition involves a wide optical hysteresis, if the antiferroelectric phase or the ferroelectric phase is selected and the bias voltage is applied and held, the selection can be made. This state can be maintained (see FIG. 8).

(3) Two orientation states in the electric field induced ferroelectric phase can be made optically equivalent. (4) Since the bias of the charge in the liquid crystal layer can be prevented,
There is no change over time in electro-optical characteristics unlike SFLC.

[0006] If these characteristics are used, time-division driving can be performed in a simple matrix without limiting the duty ratio. As an example of a driving method known to date, M. Yamawaki et.
l .: Digest of Japan Display '89, p26 (1989).

Hereinafter, a conventional method of driving an antiferroelectric liquid crystal device will be described with reference to the drawings. FIG. 6 is a cross-sectional view of the antiferroelectric liquid crystal element, in which two glass substrates 1,
2, transparent electrodes 4, 5 and insulating films 7, 8 and alignment films 9, 10
And a cell is formed by sandwiching an antiferroelectric liquid crystal 6 between two glass substrates 1 and 2 in which a transparent electrode 4 and a transparent electrode 5 are arranged to face each other. Polarizing plates 11 and 12 whose polarization axes are orthogonal to each other are provided. 3 is a seal resin. One of the transparent electrodes 4 and 5 is a scanning electrode, and the other is a signal electrode. The transparent electrode 4 and the transparent electrode 5 are arranged orthogonally with the antiferroelectric liquid crystal 6 and the like interposed therebetween.

FIG. 7 is a diagram for explaining the display principle by the conventional driving method. X and y in FIG. 7 indicate the same directions as x and y in FIG. In FIG. 7, OA is the optical axis of the antiferroelectric phase, OF (+), OF (−).
Are the optical axes of (+) and (-) of the ferroelectric phase, respectively, Ps
(+) And Ps (-) are ferroelectric phase (+),
(−) Spontaneous polarization, θ (+), θ (−) are optical axis OF
(+) And OF (-) are angles formed by the optical axis OA.

FIG. 8 is a diagram showing the electro-optical characteristics of the antiferroelectric liquid crystal device, and shows the relationship between the applied voltage and the light transmittance. In FIG. 8, V (F−A) s is a voltage at which the ferroelectric state is changed from the ferroelectric state to a sufficiently antiferroelectric state on the positive voltage side,
A) t is the voltage at which the ferroelectric state starts to change from the ferroelectric state to the antiferroelectric state on the positive voltage side, V (AF) s is the voltage at which the ferroelectric state is sufficiently changed from the antiferroelectric state to the positive voltage side, V ( AF) t
Is the voltage at which the ferroelectric state starts to change from the antiferroelectric state on the positive voltage side, -V (FA) s is the voltage at which the antiferroelectric state is sufficiently changed from the ferroelectric state on the negative voltage side, and -V (F -A) t is a voltage at which the ferroelectric state starts to change from the ferroelectric state to the negative voltage side, -V (AF) s is a voltage at which the ferroelectric state is sufficiently changed from the antiferroelectric state to the negative voltage side, −V (A−F) t is a voltage at which the ferroelectric state starts to change from the antiferroelectric state on the negative voltage side.

FIG. 9 is a driving waveform diagram according to a conventional driving method. Here, (a) shows the applied voltage waveform a1 of each scanning electrode,
a2,... an, Vr is a scanning voltage of a write pulse having a pulse width τp, and Vb is a holding voltage having the same polarity as the scanning voltage Vr. (B) shows applied voltage waveforms b1, b2,..., Bn of each signal electrode, and Vs is a selection voltage.

FIG. 10 shows a composite waveform (VLC) applied to the liquid crystal when the voltage shown in FIG. 9 is applied. In this driving method, the frame period includes a selection period including two pulses, a non-selection period including a group of pulses having the same polarity to maintain the display, and erasing (resetting) for canceling the display.
Period. In each frame period, a positive polarity frame period F '(+), F
(+) And subsequent negative frame periods F '(-) and F (-) to which a negative voltage is applied.

The display principle based on this driving method will be described.
As shown in FIG. 7, the optical axis OA in the antiferroelectric phase is orthogonal to the smectic layer. And the polarizing plate 11 in FIG.
When the device 12 is set so that one of its polarization axes is parallel to the optical axis OA, the device is in a dark state (temporarily OFF). In this state, the frame F '(+) or F' (-) shown in FIG.
│Vw2│ <│V (A−
F) If t | (see FIG. 8), the change in the light transmittance is slight, and the OFF state can be maintained. On the other hand, FIG.
When the voltage waveform in the frame F (+) or F (-) of 0 is applied, if | Vw1 |> | V (AF) s | (see FIG. 8), the liquid crystal responds, and Optical axis OF
(+), OF (-) and spontaneous polarization Ps (+), Ps (-)
To the ferroelectric phase (+) and the ferroelectric phase (−) having the optical axes OF (+) and OF (−) with respect to the polarization axis and the angle θ.
(+) Or θ (-), light state (tentatively ON)
Becomes Since the angles θ (+) and θ (−) are equal, both can be treated as optically equivalent.

[0013]

However, the conventional driving method has the following problems. That is, when the conventional two-pulse driving as shown in FIG. 9 is used, the frequency of the non-selection period varies depending on the display data, the threshold characteristics change, and there is a problem that crosstalk occurs.

Further, since there is a limit to the drive voltage that can be used, the pulse width τp required for driving to switch from the antiferroelectric phase to the ferroelectric phase at a low temperature becomes large, and the selection period (2
× τp) becomes large, so that the time required for writing one screen, which is expressed by the product of the selection period and the number of scanning lines, that is, the frame time becomes long, causing a problem that flicker is felt.

If the selection period is driven by one pulse,
Even if a longer pulse width is used than before, the selection period can be shortened, the frame time can be shortened, and flicker can be reduced, but the average voltage during the non-selection period differs greatly depending on the display data. There has been a problem that the threshold characteristic changes and more crosstalk occurs.

As a typical display pattern, FIG. 11 shows a conventional two-pulse drive waveform of a full-bright (white) display and a checkerboard pattern display, and shows a threshold characteristic of a difference in display pattern in that case. The changes are shown in FIG.

An object of the present invention is to provide a driving method and a driving apparatus for an antiferroelectric liquid crystal element which can suppress a change in threshold characteristics due to a difference in display pattern and reduce crosstalk. .

[0018]

In order to achieve this object, the present invention performs m (m is a natural number of 2 or more) duty drives, and sets n (n is different from m and the least common multiple of m). Each time a scan electrode of (a natural number whose quotient divided by n is an odd number) is selected, the polarities of the voltage applied to the scan electrode and the voltage applied to the signal electrode are inverted.

By doing so, it is possible to perform AC conversion of the signal, suppress a change in the threshold characteristic due to a difference in display pattern, and reduce crosstalk.

[0020]

According to a first aspect of the present invention, there is provided a method of driving an anti-ferroelectric liquid crystal element, comprising: a plurality of scanning electrodes arranged in stripes; When driving an antiferroelectric liquid crystal element having a plurality of arranged signal electrodes, a scanning voltage is applied to each scanning electrode during a selection period in one frame period, and during a non-selection period following the selection period. A method for driving an antiferroelectric liquid crystal element, wherein a holding voltage having the same polarity as the scanning voltage is applied, and a selection voltage and a non-selection voltage having different polarities are applied to each signal electrode in accordance with display data. (M is a natural number of 2 or more) duty drive, and n (n is m
Each time a scan electrode is selected (which is a natural number in which the quotient obtained by dividing the least common multiple of m by n and this n is an odd number), the polarity of the voltage applied to the scan electrode and the polarity of the voltage applied to the signal electrode are inverted. It is characterized by the following.

According to this driving method, m duty driving is performed, and every time n scanning electrodes are selected, the polarity of the voltage applied to the scanning electrodes and the polarity of the voltage applied to the signal electrodes are inverted. Signals can be exchanged, threshold characteristics due to differences in display patterns can be suppressed, and crosstalk can be reduced.

According to a second aspect of the present invention, there is provided a method of driving an antiferroelectric liquid crystal element, wherein an erasing period is provided after a non-selection period in one frame period, and the erasing period has a polarity different from that of the holding voltage in the non-selection period. A reset voltage or a zero reset voltage is applied to the scan electrode.

By providing the erasing period as described above,
The response time represented by the sum of the rise and fall of the liquid crystal display element can be shortened.

According to a third aspect of the present invention, there is provided a method of driving an antiferroelectric liquid crystal element, wherein the selection period comprises an application period of one pulse of a scanning voltage. As described above, by making the selection period an application period of one pulse of the scanning voltage, the time required for writing one screen, that is, the frame time, that is, the half of the frame time can be reduced as compared with the case where the selection period is made up of two pulses, and the flicker can be obtained. Can be reduced.

According to a fourth aspect of the present invention, in the method of driving an antiferroelectric liquid crystal element, n is set to 9 or less. It is preferable to set n in this way in order to suppress a change in threshold characteristics due to a difference in display pattern.

According to a fifth aspect of the present invention, there is provided a driving device for an antiferroelectric liquid crystal element, wherein a plurality of scanning electrodes arranged in stripes and a plurality of scanning electrodes arranged in a direction orthogonal to the scanning electrodes via the antiferroelectric liquid crystal. An apparatus for driving an antiferroelectric liquid crystal element having a signal electrode applies a scanning voltage to each scanning electrode during a selection period in one frame period,
A scanning signal driving circuit for applying a holding voltage having the same polarity as the scanning voltage during a non-selection period following the selection period, and applying a selection voltage and a non-selection voltage having different polarities to each signal electrode according to display data. A display signal circuit and m lines (m is 2
Each time a means for performing duty driving of the above (natural number) and n scanning electrodes (n is a natural number different from m and a quotient obtained by dividing the least common multiple of m by n) is n)
A polarity signal generation circuit that generates a polarity signal for inverting the polarity of the voltage applied to the scanning electrode and the voltage applied to the signal electrode, the scanning signal driving circuit includes:
The polarity of the voltage applied to the scanning electrode according to the polarity of the polarity signal in the selection period, the display signal circuit,
The polarity of the voltage applied to the signal electrode is set according to the polarity signal.

According to this configuration, m duty driving operations are performed, and every time n scanning electrodes are selected, the polarity of the voltage applied to the scanning electrodes and the polarity of the voltage applied to the signal electrodes are determined according to the polarity signal. , The signal is converted into an alternating current, and the change in the threshold characteristic due to the difference in the display pattern is suppressed, so that the crosstalk can be reduced.

According to a sixth aspect of the present invention, in the driving apparatus for an antiferroelectric liquid crystal element, an erasing period is provided after a non-selection period in one frame period, and a reset having a polarity different from a holding voltage in the non-selection period is provided in the erasure period. A means for applying a voltage or a reset voltage of zero to the scan electrode is provided.

By providing such an erasing period,
The response time represented by the sum of the rise and fall of the liquid crystal display element can be shortened.

An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, an antiferroelectric liquid crystal element as shown in FIG. 6, that is, a substrate 1 having a plurality of scanning electrodes (for example, transparent electrodes 4) arranged in stripes, and a plurality of stripes arranged in stripes A substrate 2 having a signal electrode (for example, a transparent electrode 5) is disposed so that the transparent electrode 4 and the transparent electrode 5 are opposed to each other, and a ferroelectric material showing two alignment states depending on the polarity of a voltage between the two substrates. Anti-ferroelectric liquid crystal 6 showing one alignment state that undergoes a phase transition to a ferroelectric liquid crystal 6
A driving method and a driving device for an antiferroelectric liquid crystal element which hold the above will be described. The transparent electrode 4 and the transparent electrode 5 serving as the scanning electrode and the signal electrode are connected to the antiferroelectric liquid crystal 6.
Are arranged in a direction perpendicular to each other with the intermediary etc. interposed therebetween.

FIGS. 1 to 3 show driving waveforms in the driving method according to the embodiment of the present invention. Here, a case where m = 6 duty driving is performed is shown. In FIG. 1, a1 to a
Reference numeral 6 denotes a scan electrode driving voltage waveform.
Reference numerals 1 to b3 denote drive voltage waveforms of the signal electrodes. 1 and 2 will be described later. C11, C22, and C23 in FIG. 3 are composite waveforms applied to the liquid crystal when the driving voltages shown in FIGS. 1 and 2 are applied.
Indicates the positions where a1 to a6, b1 to b3, C11, C22, and C23 are applied, and the display state of each picture element is indicated by ○ (bright state) and ● (dark state).

The feature of this embodiment is that m duty driving is performed and every time n scanning electrodes are selected,
Inverting the voltage applied to the scanning electrodes and the voltage applied to the signal electrodes. Here, a description will be given assuming that m = 6 and n = 2. That is, if n = 2 when m = 6, this n = 2 is the least common multiple of m = 6 “6”
Divided by n = 2 corresponds to a natural number that is 6 ÷ 2 = 3, that is, an odd number.

As shown in FIG. 1, during one frame period of the scan electrode drive voltage, a selection period during which the scan voltage Vr is applied as a write pulse is followed by a hold voltage Vb having the same polarity as the scan voltage Vr. A non-selection period is applied, followed by an erasing period in which the applied voltage is set to zero (reset voltage). Note that τp is the pulse width of the write pulse, and the pulse width τp here is (the time of) the selection period.

D shown in FIGS. 1 and 2 is a polarity signal whose polarity is inverted every time n = 2 scanning electrodes are selected. The polarity of the voltage applied to the scanning electrode and the signal electrode is set according to the polarity of the polarity signal. FIG. 5 shows the relationship between the polarity of the polarity signal d and the polarities of the scanning voltage, the selection voltage, and the non-selection voltage.

Therefore, as shown in the drive voltage waveforms (a1 to a6) of the scan electrodes in FIG. 1, the scan voltage Vr of the write pulse in the selection period and the subsequent non- Holding voltage Vb during selection period
And the polarity of the reset voltage during the erase period. For example, in the scan electrode waveforms a1 and a2, the polarity signal d in each selection period has a positive polarity, and each scan voltage Vr has a positive polarity. In the selection period of the scan electrode waveform a3, the polarity signal d has a negative polarity. Therefore, the scanning voltage Vr is also inverted to the negative polarity. The holding voltage Vb during the non-selection period and the reset voltage during the erasing period are set according to the polarity of the scanning voltage Vr. Here, since the reset voltage in the erasing period is set to zero, the same holds true even when inverted. Note that the reset voltage may be set to a voltage having a polarity opposite to that of the scanning voltage Vr and the holding voltage Vb instead of zero. In that case, the scanning voltage Vr and the holding voltage V
When b has a positive polarity, the reset voltage has a negative polarity, and when the scanning voltage Vr and the holding voltage Vb have a negative polarity, the reset voltage has a positive polarity.

Further, the drive voltage waveform (b
1 to b3...), The polarity of the selection voltage and the non-selection voltage of the signal data of the display pattern is set according to the polarity of the polarity signal d.

Next, a specific embodiment of the present invention will be described. Actually, an antiferroelectric liquid crystal device as shown in FIG. 6 was manufactured and driven. That is, the two glass substrates 1 and 2
The transparent electrodes 4 and 5 of ITO are formed thereon, the insulating films 7 and 8 are formed thereon, and the polyimide film is further formed thereon. And 10. Then, a panel was formed such that the rubbing directions were parallel or anti-parallel with the substrates facing each other, and the gap was set to 1.7 μm. Liquid crystal material 4- (1
-methylheptyloxycarbonyl) phenyl 4'-octyloxybipheny
l-4-carboxylate (MHPOBC) is heated and sealed, and the environmental temperature is reduced to antiferroelectric chiral smectic C phase (SmCA
(* Phase) was used. Then, the temperature of the element is maintained at 90 ° C., the pulse width τp = 80 μs,
When driven under the above conditions with Vr = 18 V, Vs = 2.7 V, Vb = 5 V, and a duty ratio of 1/240,
The contrast ratio was 1:20, and a display with little crosstalk was realized. Further, gradation display can be realized by using amplitude modulation or pulse width modulation.

Next, a specific comparison result of display between the driving method according to the present embodiment and the driving method according to the prior art will be described. The drive waveforms when the entire surface is displayed in white (bright) and when the checkerboard pattern is displayed are the waveforms shown in FIG. 11 as described above in the conventional case, but in the case of the present embodiment, they are respectively shown in FIG. C23 and C22 shown in FIG. Table 1 shows the voltages at which the luminance change in the case of the two-pulse drive and the one-pulse drive in the case of the driving method of the present invention and the case of the conventional driving method reaches 50% in the case of full white display and checkered pattern display, respectively. And the frame time. Note that the pulse width in this case is τp = 80 μ
s.

[0039]

[Table 1]

As can be seen from Table 1, in the case of the driving method of the present invention, the threshold shift voltage ΔV depending on the display pattern could be made smaller than in the case of the conventional driving method.
Further, the threshold shift voltage Δ
It has been found that in order to reduce V, it is desirable to set n to 9 or less in the driving of the present invention.

In the above embodiment, the driving waveform of the scanning electrode has been described with reference to the example in which one frame shown in FIG. 1 includes a selection period, a non-selection period, and an erasing period. However, the present invention is not limited to this. Even when the driving voltage waveform is a waveform in which one frame includes a selection period and a non-selection period, the same effect as described above can be obtained. By providing the erasing period, the response time represented by the sum of the rise and fall of the liquid crystal display element can be shortened.

Although FIGS. 1 to 4 show the case of one-pulse drive in which the selection period is made up of one pulse, Table 1 shows that even in the case of two-pulse drive in which the selection period is made up of two pulses, the threshold depends on the display pattern. It can be seen that the value shift voltage ΔV can be reduced. In the case of one-pulse driving, the frame time required for writing one screen can be reduced to half and flicker can be reduced as compared with the case of two-pulse driving.

Further, in the above-described embodiment, the polarity of the voltage applied to the scanning electrodes and the polarity of the voltage applied to the signal electrodes are inverted each time the m-number of duty driving is performed and the n-number of scanning electrodes are selected. A driving method characterized in that m =
6, the case where n = 2 has been described as an example. However, when m is a natural number of 2 or more, and n is a natural number different from m and a quotient obtained by dividing the least common multiple of m by this n is an odd number, In this method, the time integral of the voltage applied to the liquid crystal can be made zero by double the time obtained from the least common multiple, and the voltage applied to the liquid crystal can be converted to AC.

A driving device for realizing the above driving method performs a m-number of duty driving and applies a voltage to each scanning electrode and a scanning electrode driving circuit having different polarities depending on display data to each signal electrode. A display signal driving circuit for applying a selection voltage and a non-selection voltage and a polarity signal generation circuit for generating a polarity signal whose polarity is inverted each time n scan electrodes are selected are provided.

Then, the scan electrode drive circuit applies a scan voltage with a positive or negative polarity to the scan electrodes according to the polarity of the polarity signal in the selection period (selection period), and in the subsequent non-selection period, the same as the scan voltage. A polarity holding voltage is applied, and during the subsequent erasing period, a reset voltage having a polarity different from the scanning voltage and the holding voltage or a zero reset voltage is applied.
In addition, the display signal drive circuit also controls the polarity of the polarity signal according to the polarity of the polarity signal.
The polarity of the selection voltage and the non-selection voltage applied to the signal electrode is set.

In this driving device, a scanning voltage, a holding voltage, and a reset voltage are applied to the scanning electrodes, and a selection voltage and a non-selection voltage are applied to the signal electrodes. Can be. Furthermore, the voltage pattern applied to the liquid crystal during a period other than the selection period differs from frame to frame, and thus the threshold characteristics are originally different from frame to frame, but the average threshold characteristics are less affected by display data. Note that an erasing period in which a reset voltage is applied to the scan electrode may not be provided.

[0047]

As described above, according to the present invention, m duty driving is performed, and every time n scanning electrodes are selected, the polarity of the voltage applied to the scanning electrodes and the polarity of the voltage applied to the signal electrodes are changed. , The signal is converted into an alternating current, and the change in the threshold characteristic due to the difference in the display pattern is suppressed, so that the crosstalk can be reduced.

Further, when the selection period is set to the application period of the scanning voltage of one pulse, the time required for writing one screen, that is, the frame time, is reduced to half compared with the case where the selection period is constituted by two pulses, and the flicker is reduced. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a driving voltage waveform of a scanning electrode and a polarity signal based on a driving method of an antiferroelectric liquid crystal element according to an embodiment of the present invention.

FIG. 2 is a diagram showing a drive voltage waveform and a polarity signal of a signal electrode based on the drive method of the embodiment.

FIG. 3 is a diagram showing a composite waveform based on the drive voltage waveforms of FIGS. 1 and 2;

FIG. 4 is a diagram showing a display state based on the composite waveform of FIG. 3;

FIG. 5 is a diagram showing a relationship between the polarity of a polarity signal and the polarities of a scanning voltage, a selection voltage, and a non-selection voltage in the embodiment.

FIG. 6 is a sectional view of an antiferroelectric liquid crystal element.

FIG. 7 is a diagram for explaining a display principle by a conventional driving method.

FIG. 8 is a diagram for explaining the electro-optical characteristics of the antiferroelectric liquid crystal element.

FIG. 9 is a driving voltage waveform diagram of a scanning electrode and a signal electrode according to a conventional driving method.

FIG. 10 is a diagram showing a composite waveform applied to the liquid crystal by the driving voltage waveform of FIG.

FIG. 11 is a diagram showing driving voltage waveforms in a case where bright (white) display and checkerboard display are performed by the conventional driving method.

FIG. 12 is a diagram illustrating a change in a threshold characteristic when bright (white) display and checkered pattern display are performed by the conventional driving method.

Claims (6)

[Claims] 1. An antiferroelectric liquid crystal element having a plurality of scanning electrodes arranged in a stripe pattern and a plurality of signal electrodes arranged in a direction orthogonal to the scanning electrodes via an antiferroelectric liquid crystal is driven. At this time, a scanning voltage is applied to each scanning electrode during a selection period in one frame period, and a holding voltage having the same polarity as the scanning voltage is applied to a non-selection period following this selection period. A method of driving an antiferroelectric liquid crystal element in which a selection voltage and a non-selection voltage having different polarities are applied according to display data, wherein m (m is a natural number of 2 or more) duty driving is performed and n ( n is a natural number different from m and a quotient obtained by dividing the least common multiple of m by this n is an odd number) Every time a scan electrode is selected, the polarity of the voltage applied to the scan electrode and the polarity of the voltage applied to the signal electrode Can be inverted The driving method of the anti-ferroelectric liquid crystal device according to claim. 2. An erasing period is provided after a non-selection period in one frame period, and a reset voltage having a polarity different from a holding voltage in the non-selection period or a zero reset voltage is applied to the scan electrode during the erasing period. 2. The method for driving an antiferroelectric liquid crystal device according to claim 1, wherein 3. The method of driving an antiferroelectric liquid crystal element according to claim 1, wherein the selection period comprises a period of applying one pulse of a scanning voltage. 4. The method for driving an antiferroelectric liquid crystal device according to claim 1, wherein n is 9 or less. 5. An antiferroelectric liquid crystal element having a plurality of scanning electrodes arranged in a stripe pattern and a plurality of signal electrodes arranged in a direction orthogonal to the scanning electrodes via an antiferroelectric liquid crystal. A scanning signal for applying a scanning voltage to each scanning electrode during a selection period in one frame period and applying a holding voltage having the same polarity as the scanning voltage during a non-selection period following the selection period. A driving circuit; a display signal circuit for applying a selection voltage and a non-selection voltage having different polarities to each signal electrode according to display data; and m means (m is a natural number of 2 or more) for duty driving; Every time n scan electrodes are selected (n is different from m and a quotient obtained by dividing the least common multiple of m by this n is an odd number), a voltage applied to the scan electrodes and a voltage applied to the signal electrodes are applied. A polarity signal generation circuit that generates a polarity signal for inverting the polarity of the voltage, wherein the scanning signal driving circuit sets the polarity of the voltage applied to the scanning electrode according to the polarity of the polarity signal in the selection period. The display signal circuit sets a polarity of a voltage applied to a signal electrode according to the polarity signal. 6. A means for providing an erasing period after a non-selection period in one frame period, and applying a reset voltage having a polarity different from the holding voltage in the non-selection period or a zero reset voltage to the scan electrode during the erasing period. The driving device for an antiferroelectric liquid crystal element according to claim 5, further comprising: