JP2001033759A - Drive method for ferroelectric liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ease or eliminate an effect of drive dispersion and to improve display quality by increasing a drive margin. SOLUTION: After a strobe pulse 3 for making an element an optional display state in a selection period is applied to a scan electrode of a ferroelectric liquid crystal display element, a TRIFLE(technique to reduce the long field latching effect) pulse 4 of the polarity opposite to the strobe pulse 3 is applied to the scan electrode, and a pause period (d) during which a scan voltage becomes 0 is provided between the applied period of the strobe pulse 3 and the applied period of the TRIFLE pulse 4. Thus, when the TRIFLE pulse 4 is applied to the scan electrode, the switching to a dark state is stabilized than the case that the pause period d is not provided, and the original effect of the TRIFLE pulse 4 is strengthened, and a non-rewrite margin is increased. Thus, the final drive margin being a common part between the non-rewrite margin and a rewrite margin is also increased necessarily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferroelectric liquid crystal display (Ferroelectric liquid crystal display) capable of improving display quality.
The present invention relates to a method for driving a crystal display (FLCD).

[0002]

2. Description of the Related Art In a conventional device using a ferroelectric liquid crystal,
If charge asymmetry (charge bias in the direction of the upper and lower substrates) occurs in the device when a drive voltage is applied, the spontaneous polarization of the ferroelectric liquid crystal responds to such asymmetric charge, and the memory property is increased. Is lost, the display quality is reduced, and furthermore, the liquid crystal is deteriorated. The above-mentioned memory property refers to an effect that the display state selected during the selection period is maintained even when not selected.

Therefore, in order to avoid such inconvenience,
For example, in Japanese Patent Application Laid-Open No. 2-267523, the above-described charge asymmetry is canceled by the following driving method. The driving method is as shown in FIG.
During or before the selection period, a blanking pulse (reset pulse) 5 for resetting the display state of the element.
1 is applied to the scan electrode, and then a strobe pulse (set pulse) 52 having an effective value to bring the element into an arbitrary display state according to the display content is applied to the scan electrode. A pulse 53 having a canceling polarity and having a product of the peak value and the pulse width smaller than the product of the peak value and the pulse width of the strobe pulse 52 is applied to the scan electrode.

That is, in the above publication, immediately after the application of the strobe pulse 52, a pulse 53 in a direction to cancel the polarity of the panel (asymmetrical charge), that is, a pulse 53 having a polarity opposite to that of the strobe pulse 52 is applied to the scanning electrode. By doing so, the instability of the memory during the non-selection period due to the polarity of the panel is avoided, and the life of the liquid crystal is extended.

[0005]

By the way, in driving the FLCD, it is necessary to secure a sufficient driving margin. The above-mentioned driving margin is an allowable range of a scanning voltage for driving the FLCD, from a threshold value sufficient for switching the FLCD to a maximum value at which crosstalk (phenomenon in which contrast is reduced) does not occur in an adjacent pixel. Say The reason why the drive margin must be sufficiently ensured is that the drive pulse of the FLCD is the same over the entire screen, and the drive pulse is rounded (waveform distortion) caused by the temperature distribution in the display surface and the wiring resistance of the electrodes. This is for relaxing the switching and obtaining good switching over the entire surface.

The above-mentioned drive margin is finally determined by an overlap between a drive margin at the time of rewriting (hereinafter referred to as a rewrite margin) and a drive margin at the time of non-rewrite (hereinafter referred to as a non-rewrite margin). The rewriting margin is a range of a scanning voltage at which rewriting is possible when an information voltage waveform for rewriting is applied to the information electrode of the FLCD. On the other hand, the above-mentioned non-rewriting margin is a range of a scanning voltage that enables non-rewriting when an information voltage waveform for non-rewriting is applied to the information electrode. Therefore, the more common parts between the rewrite margin and the non-rewrite margin, the larger the final drive margin.

Here, in a ferroelectric liquid crystal display device in which a chiral smectic liquid crystal is sandwiched between a pair of substrates on which scanning electrodes and information electrodes are respectively formed, one of the conventional driving waveforms shown in FIG. When the waveform shown in FIG. 8, which is a modification, was applied to the scanning electrode and the information electrode,
Although the blanking (reset) is more effective in the waveform shown in FIG.
0 to 32.0 V, and the non-rewriting margin is 31.0 V.
〜34.0V. Therefore, the final driving margin as each common part is 31.0 to 32.0 V
And the margin width was 1.0 V, which was not sufficient.

As described above, in the conventional driving method, since the margin width of the final driving margin is not enough, that is, 1.0 V, there is a driving variation due to uneven threshold, uneven temperature and uneven waveform in the panel surface. In this case, this variation cannot be covered by the above-mentioned spread of the drive margin.
As a result, there is a problem that uniform display cannot be performed over the entire area of the panel surface.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to increase the driving margin to eliminate the influence of the driving variation and thereby improve the display quality. It is an object of the present invention to provide a method of driving a ferroelectric liquid crystal display device which can be performed.

[0010]

In order to solve the above-mentioned problems, a method of driving a ferroelectric liquid crystal display device according to the present invention comprises a method of driving a ferroelectric liquid crystal display element between a pair of substrates on which scanning electrodes and information electrodes are formed. In the method of driving a ferroelectric liquid crystal display element filled with a dielectric liquid crystal material, a strobe pulse for setting the element to an arbitrary display state in a selection period is applied to the scan electrode, and then the strobe pulse is reversed from the strobe pulse. A pulse having a polarity is applied to the scan electrode, and a pause period in which a scan voltage becomes 0 is provided between the application period of the strobe pulse and the application period of the reverse polarity pulse.

According to the above arrangement, a scanning electrode or an information electrode is formed on each of the pair of substrates sandwiching the ferroelectric liquid crystal material. While applying a strobe pulse to the scan electrode during the selection period, for example, applying an information voltage for rewriting or non-rewriting to the information electrode in synchronization with the strobe pulse, the scan electrode and the information electrode The alignment state of the liquid crystal material in the intersecting region is defined, and the element is in an arbitrary display state (bright state or dark state).

Here, since a pulse having a polarity opposite to that of the strobe pulse is applied to the scan electrode after application of the strobe pulse, the asymmetry of the charge caused by the application of the strobe pulse is canceled by the reverse polarity pulse. . As a result, the spontaneous polarization of the ferroelectric liquid crystal material is not inverted, and the memory effect that the display state selected during the selection period is maintained even during the non-selection period is not lost.

Also, originally, the strobe pulse includes:
While there is an effect of switching the display state to an arbitrary first state (for example, a bright state), the reverse polarity pulse changes the display state to a second state opposite to the above (for example, a dark state). State). As described above, the strobe pulse and the reverse polarity pulse promote switching to the opposite display state. However, when the reverse polarity pulse is applied to the scan electrode immediately after the application of the switching pulse, the reverse polarity pulse is applied. The pulse has no relation to the switching to the second state by the application of the opposite polarity pulse.

On the other hand, as in the present invention, when a pause period in which the scanning voltage becomes 0 is interposed between the application period of the strobe pulse and the application period of the reverse polarity pulse,
When the reverse polarity pulse is applied to the scan electrode, the reverse polarity pulse has a new effect of contributing to switching to the second state, and the state changes to the second state as compared with the case where the idle period is not provided. Switching can be more stabilized. As a result, the above-described original effect of the reverse polarity pulse is enhanced, and the non-rewriting margin (the range of the scanning voltage at which non-rewriting is possible when an information voltage waveform for non-rewriting is applied to the information electrode) increases. . As a result,
The final drive margin, which is the common part of the non-rewrite margin and the rewrite margin (the range of the scan voltage at which rewrite is possible when the information voltage waveform for rewrite is applied to the information electrode of the FLCD), also inevitably increases. I do.

Therefore, according to the above configuration, even if there are drive variations due to threshold unevenness, temperature unevenness, and waveform distortion unevenness in the panel surface, these drive unevenness can be reliably covered with the increased drive margin. . As a result, even if there is the drive variation, uniform display can be performed over the entire area of the panel surface.

In order to solve the above-mentioned problems, the driving method of the ferroelectric liquid crystal display device according to the present invention is arranged such that the number of slots of the information voltage waveform corresponding to the sum of the application period of the strobe pulse and the pause period is reduced. The application period and the idle period are set so as not to be an integral multiple of the number of slots of the information voltage waveform corresponding to the selection period.

The number of slots of the information voltage waveform corresponding to the sum of the application period of the strobe pulse and the pause period is as follows:
When the number of slots of the information voltage waveform corresponding to the selection period is an integral multiple of the number of slots, the information voltage waveform appears in synchronization with the reverse polarity pulse. In this case, the information voltage behaves extremely as a switching pulse having a polarity opposite to that of the strobe pulse. As a result, normal rewriting and non-rewriting in accordance with the driving waveform cannot be performed, and the driving margin decreases or disappears.

However, in the present invention, the number of slots of the information voltage waveform corresponding to the sum of the application period of the strobe pulse and the pause period is an integer multiple of the number of slots of the information voltage waveform corresponding to the selection period. Since the application period and the quiescent period are set so as not to occur, the information voltage waveform does not appear in synchronization with the reverse polarity pulse. As a result, the drive margin can be prevented from decreasing or disappearing despite the provision of the suspension period, and the above-described effect of improving the display quality can be reliably obtained.

In order to solve the above-mentioned problems, the driving method of the ferroelectric liquid crystal display element according to the present invention does not reduce the effect of the opposite polarity pulse canceling out the asymmetry of the charge caused by the strobe pulse. Further, the above-mentioned idle period is set so that the allowable range of the scanning voltage for driving the element is maximized.

When the pause period is increased, the stability of switching of the display state to the second state by the reverse polarity pulse is also increased. Therefore, the allowable range of the scanning voltage for driving the element, that is, the driving margin Will also increase. However, if the pause period is excessively increased, the original effect of the reverse-polarity pulse, which cancels the asymmetry of the charge caused by the strobe pulse, decreases, and this leads to deterioration of the driving characteristics.

Therefore, as in the present invention, by improving the display quality by setting the idle period so as to maximize the drive margin without reducing the effect of the pulse of the opposite polarity, the display quality can be improved. Can be maximized without deterioration.

In order to solve the above-mentioned problems, a driving method of a ferroelectric liquid crystal display device according to the present invention includes a blanking pulse for resetting a display state of the device before the application of the strobe pulse, and a blanking pulse. A pulse having a polarity opposite to that of the pulse is applied to the scan electrode.

According to the above configuration, by applying the blanking pulse to the scan electrode before the application of the strobe pulse, the display state is reset to, for example, a dark state regardless of whether the previous state is a bright state or a dark state. You. This allows
When the strobe pulse is applied, the display state can be reliably switched to the bright state.

Further, by applying a pulse having a polarity opposite to that of the blanking pulse, for example, before, after, or both before and after the blanking pulse, the charge asymmetry caused by the application of the blanking pulse is reduced. can do.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described.
The following is a description based on FIGS. 1 to 6.

A ferroelectric liquid crystal display device (FLCD) according to the present embodiment is a liquid crystal cell in which a chiral smectic liquid crystal as a ferroelectric liquid crystal material is filled between a pair of substrates on which a scanning electrode and an information electrode are respectively formed. have. The liquid crystal cell is disposed between the polarizing plates so that the liquid crystal cell transitions to a bright state by applying an appropriate positive voltage and to a dark state by applying an appropriate negative voltage.

The chiral smectic liquid crystal as the liquid crystal material is, for example, FLC-1 developed by the present applicants. This liquid crystal material shows a minimum value in response speed-dependence on applied voltage, and its orientation is C2U orientation. The liquid crystal material is not limited to the above-mentioned FLC-1, and the effects of the present invention can be obtained even if another liquid crystal material called FDS-71 or another liquid crystal material is used.
Here, the general properties of FLC-1 and FDS-71 are shown in Table 1.

[0028]

[Table 1]

A strobe pulse is applied to the scanning electrode to bring the element into an arbitrary display state (for example, a bright state) according to the display content, and an information voltage for rewriting or non-rewriting the information electrode is synchronized with the strobe pulse. Is applied, the alignment state of the liquid crystal material in a region where the scanning electrode and the information electrode intersect is defined.

A scanning voltage and an information voltage are respectively applied to the scanning electrode and the information electrode of the FLCD having the above configuration at timings as shown in FIG. The scanning voltage waveform is roughly composed of a blanking section and a strobe section.

First, in the blanking section, a blanking pulse (reset pulse) for rewriting to a dark state regardless of whether the previous state is a dark state or a bright state.
1 is applied to the scanning electrode. By applying the blanking pulse 1, the display state of the element is reset. Then, following the blanking pulse 1, a kickback pulse 2 having a polarity opposite to that of the blanking pulse 1 is applied to the scan electrode. The kickback pulse 2 is given to alleviate the asymmetry of the charge generated by the blanking pulse 1.

The kickback pulse 2 may be applied to the scanning electrodes before the blanking pulse 1 or both before and after the blanking pulse 1. Of course, it is necessary to consider the DC balance within the frame period.

Subsequently, in the strobe section, a strobe pulse (set pulse) 3 is applied to the scan electrodes. In the present embodiment, the strobe pulse 3 is extended to outside the selection period and applied to the scan electrodes. This extension is known as the Malvern extension (Liquid Crystals 13, 597, 1993). On the other hand, in synchronization with the strobe pulse 3,
An information voltage waveform (rewrite waveform or non-rewrite waveform) is applied to the information electrode to cause the element to transition to either a rewrite state (bright state or white state) or a non-rewrite state (dark state or black state). As the information voltage waveform, for example, the DRAM A3 (11
0) The waveform (Proc. Of IRDC '97 L-40 (1997)) is used.

Next, after the strobe pulse 3, a pause period (section where the scanning voltage is 0) d is provided, and thereafter, a kickback pulse having a polarity opposite to that of the strobe pulse 3 is applied to the scanning electrode. Hereinafter, this kickback pulse is referred to as TRIFLE (Tequnique to Reduce the Ionic Field L).
atching Effect) Pulse 4.

The TRIFLE pulse 4 has a polarity opposite to that of the strobe pulse 3, and thus has a function of canceling the asymmetrical bias of the charge caused by the strobe pulse 3. Thus, the spontaneous polarization of the liquid crystal material is not inverted, and the memory effect that the display state selected in the selection period is maintained even in the non-selection period is not lost. The product of the peak value and the pulse width of the TRIFLE pulse 4 is set to be smaller than, for example, the product of the peak value and the pulse width of the strobe pulse 3.

In this embodiment, as an example, the selection period is set to 3 slots, the strobe pulse 3 extended by the Malvern extension is 6 slots, and the TRIFLE pulse 4
Uses a drive waveform composed of four slots, but the present invention is not limited to this.

Here, the change of the minimum value min and the maximum value max of the rewrite margin and the change of the minimum value min and the maximum value m of the non-rewrite margin when the pause period d is changed.
The change of ax is shown in FIG. 3, and the results of the rewrite margin and the non-rewrite margin are shown in Table 2. The above-mentioned FLC-1 is used as a liquid crystal material of the element.

[0038]

[Table 2]

When the pause period d is 0 slot, the above-described conventional example is shown. Thus, strobe pulse 3
When there is no pause period d between the non-rewriting margin and the TRIFLE pulse 4, the rewriting margin is on the lower voltage side compared to the non-rewriting margin, and the margin width of the common portion (final driving margin) is 1.0V. This is as described above.

On the other hand, in the present embodiment, by providing one or more idle periods d, the idle period d becomes zero.
The non-rewrite margin shifts to a lower voltage side than in the case of the slot, and as a result, the final drive margin, which is a common part between the rewrite margin and the non-rewrite margin, increases. In particular, when the idle period d is set to 4 slots or 5 slots, a margin width of 3.0 V is obtained. This is considered to be due to the following reasons.

That is, the strobe pulse 3 has an effect of switching the display state to a bright state, whereas the TRIFLE pulse 4 has an effect of switching the display state to a dark state. As described above, the strobe pulse 3 and the TRIFLE pulse 4 promote switching to the opposite display state. However, when the TRIFLE pulse 4 is applied to the scan electrode immediately after the application of the strobe pulse 3, the TRIFLE pulse 4 becomes TRI
The switching to the dark state by the application of the FLE pulse 4 is irrelevant. Originally, the TRIFLE pulse 4 is a pulse for alleviating the charge asymmetry in the strobe pulse 3, and rewriting and non-rewriting are defined only by the strobe pulse 3 instead of the TRIFLE pulse 4.

On the other hand, strobe pulse 3 and TR
By providing a pause period d in which the scanning voltage becomes 0 between the IFLE pulse 4 and the TRIFLE pulse 4 applied to the scanning electrode, a new effect of the TRIFLE pulse 4 contributing to switching to the dark state appears. Thus, the switching to the dark state can be more stabilized as compared with the case where the pause period d is not provided. As a result, the original switching effect of the TRIFLE pulse 4 is strengthened, and the non-rewriting margin is increased. As a result, the final driving margin, which is a common part between the non-rewriting margin and the rewriting margin, is necessarily increased. Become.

As described above, according to the present invention, the idle period d is provided between the strobe pulse 3 and the TRIFLE pulse 4.
Is provided, the non-rewriting margin can be increased, and the final driving margin can be increased. As a result, even if there are drive variations due to threshold unevenness, temperature unevenness, and waveform distortion unevenness in the panel surface, these drive unevenness can be reliably covered with the increased drive margin, thereby reducing the influence of the drive unevenness. Can be reduced or eliminated. Therefore, by providing the pause period d, it is possible to perform a uniform display over the entire area of the panel surface and improve the display quality even if the drive variation occurs.

In Table 2, the pause period d is 3
In the case of slots and six slots, the sum of the application period t (six slots) of the strobe pulse 3 and the idle period d becomes nine slots and twelve slots, respectively, which are integer multiples of the selection period (three slots). Therefore, no drive margin is obtained. FIG. 4 shows, as an example, the scanning voltage waveform and the information voltage waveform when the idle period d is three slots.

When the sum of the application period t and the quiescent period d is an integral multiple of the selection period, no driving margin can be obtained because the information voltage waveform is synchronized with the TRIFLE pulse 4,
The reason for this is that it behaves extremely as a switching pulse having a polarity opposite to that of the strobe pulse 3. In this case, T
Depending on the information voltage waveform synchronized with the RIFLE pulse 4, the light state may be rewritten from the dark state. That is, an incorrect state is rewritten according to the pixel pattern. As a result, in the above case, normal rewriting and non-rewriting cannot be performed, and the driving margin decreases or disappears.

Therefore, in order to reliably increase the drive margin, considering the above, the number of slots of the information voltage waveform corresponding to the sum of the application period t of the strobe pulse 3 and the above-mentioned pause period d is determined. The application period t and the idle period d need to be set so as not to be an integral multiple of the number of slots of the information voltage waveform corresponding to the selection period.

The pause period d is set to one slot or two slots.
4 slots or 5 rather than driving as slots
The largest value is obtained as the margin width of the drive margin when driving as a slot. This is because the opening between the strobe pulse 3 and the TRIFLE pulse 4 causes the TRIFLE pulse 4 to contribute to an increase in the non-rewrite margin, and the non-rewrite margin expands as the pause period d increases. However, if the pause period d is set too long, the original effect of the TRIFLE pulse 4 for canceling the charge asymmetry caused by the strobe pulse 3 is reduced, and the driving characteristics deteriorate.

Therefore, as the pause period d, the asymmetry of the charge caused by the strobe pulse 3 is represented by T
It is desirable that the driving margin, that is, the allowable range of the scanning voltage for driving the element is set to be the maximum without reducing the effect of the RIFLE pulse 4 canceling out.

Next, in the case where the liquid crystal material of the element is composed of FDS-71, the change of the minimum value min and the maximum value max of the drive margin when the pause period d was changed was examined. The results are shown in FIG. Note that the same scanning voltage waveform as that in the case of using the liquid crystal material FLC-1 was used.

[0050]

[Table 3]

When the above liquid crystal material FDS-71 was used, the same results were obtained as when the liquid crystal material FLC-1 was used. That is, when the idle period d is 0 slot (conventional example), the margin width of the final drive margin is 1.5
In contrast, when the pause period d was 1, 2, 4, and 5 slots, the drive margin was certainly increased from 1.5 V. In particular, when the idle period d is 4 slots,
The margin width of the drive margin has increased to the maximum of 4.0V.

Also in the above liquid crystal material, when the sum of the application period t of the strobe pulse 3 and the pause period d is an integral multiple of the selection period, that is, when the pause period d is 3 slots and 6 slots, The drive margin could not be obtained.

Next, in the case where the above-mentioned liquid crystal material FDS-71 is used, a strobe pulse 3 is applied to five slots,
FIG. 6 and Table 4 show the results when a scanning voltage waveform in which the IFLE pulse 4 has four slots is applied to the scanning electrodes.

[0054]

[Table 4]

When the idle period d is 0 slot (conventional example)
Then, the margin width of the drive margin is 3.0 V, whereas when the idle period d is 2, 3, 5, and 6 slots, the drive margin is more reliably increased than the above 3.0 V. In particular, when the idle period d is 5 slots or 6 slots, the margin width of the drive margin has increased to the maximum of 4.5V.

On the other hand, if the idle period d is one slot or four
When a slot occurs, the application period t of the strobe pulse 3
And the idle period d are 6 slots and 9 slots, respectively, which are integral multiples of the selection period (3 slots), so that the margin width of the drive margin is reduced or eliminated.

As described above, the effects of the present invention can be obtained regardless of the type of ferroelectric liquid crystal material by appropriately setting the application period t of the strobe pulse 3 and the pause period d in consideration of the selection period. You can say that you can.

[0058]

As described above, the driving method of the ferroelectric liquid crystal display device according to the present invention is such that the strobe pulse for bringing the device into an arbitrary display state during the selection period is applied to the scan electrode, and A pulse having a polarity opposite to that of the strobe pulse is applied to the scan electrode, and a pause period in which the scan voltage becomes 0 is provided between the application period of the strobe pulse and the application period of the reverse polarity pulse.

Therefore, since a pulse of the opposite polarity is applied to the scan electrode after the application of the strobe pulse, the asymmetry of the charge caused by the application of the strobe pulse is canceled by the reverse polarity pulse. As a result, the spontaneous polarization of the ferroelectric liquid crystal material is not inverted, and the effect that the memory effect in which the display state selected in the selection period is maintained in the non-selection period is lost can be avoided. .

Further, by providing a pause between the application period of the strobe pulse and the application period of the reverse polarity pulse, when the reverse polarity pulse is applied to the scan electrode, the pause is not provided. The switching to the second state (for example, the dark state) can be more stabilized as compared with. This enhances the original effect of the reverse polarity pulse for switching to the second state, and increases the non-rewrite margin. As a result, the final drive margin, which is a common part between the non-rewrite margin and the rewrite margin, necessarily increases.

Therefore, even if there are drive variations due to threshold unevenness, temperature unevenness, and waveform distortion unevenness in the panel surface, these drive unevenness are reliably covered by the increased drive margin, and the influence of the drive unevenness is reduced or reduced. Can be eliminated. As a result, even if there is the above-mentioned drive variation, there is also an effect that uniform display can be performed over the entire area of the panel surface.

As described above, in the driving method of the ferroelectric liquid crystal display element according to the present invention, the number of slots of the information voltage waveform corresponding to the sum of the application period of the strobe pulse and the pause period is set to the selection period. The application period and the idle period are set so as not to be an integral multiple of the number of slots of the information voltage waveform corresponding to the above.

Therefore, since the information voltage waveform does not appear in synchronization with the reverse polarity pulse, the information voltage does not extremely behave as a switching pulse having the polarity opposite to that of the strobe pulse, and a pause period is provided. Nevertheless, the drive margin does not decrease or disappear. Therefore, there is an effect that the above-described effect obtained by providing the pause period can be reliably obtained.

As described above, the driving method of the ferroelectric liquid crystal display element according to the present invention is not limited to the above-described method in which the effect of canceling the asymmetry of the charge caused by the strobe pulse by the pulse of the opposite polarity is reduced. The above-described idle period is set so that the allowable range of the scanning voltage for driving is maximized.

Therefore, the maximum drive margin can be obtained without reducing the original effect of the reverse polarity pulse, and the display quality can be maximized without deteriorating the drive characteristics. It works.

As described above, the driving method of the ferroelectric liquid crystal display element according to the present invention is such that the blanking pulse for resetting the display state of the element before the application of the strobe pulse and the blanking pulse opposite to the blanking pulse are applied. A polarity pulse is applied to the scanning electrode.

Therefore, since the display state is reset before the application of the strobe pulse, the display state can be switched to a state different from the reset state when the strobe pulse is applied. Further, by applying a pulse having a polarity opposite to that of the blanking pulse, for example, before, after, or both before and after the blanking pulse, it is possible to reduce the asymmetry of the charge caused by the application of the blanking pulse. It has the effect of being able to.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a method of driving a ferroelectric liquid crystal display device of the present invention, and is a waveform diagram showing a scanning voltage waveform and an information voltage waveform applied to a scanning electrode and an information electrode of the device. is there.

FIG. 2 is a waveform diagram showing a rewrite waveform and a non-rewrite waveform in an information voltage waveform.

FIG. 3 is a graph showing a change in each of a minimum value and a maximum value of a rewrite margin and a non-rewrite margin due to a change in an idle period when a certain liquid crystal material is used.

FIG. 4 is a waveform diagram showing a scanning voltage waveform and an information voltage waveform when a sum of a strobe pulse application period and a pause period is an integral multiple of a selection period.

FIG. 5 is a graph showing a change in a minimum value and a maximum value of a drive margin due to a change in a quiescent period when another liquid crystal material is used.

FIG. 6 is a graph showing a change in a minimum value and a maximum value of a drive margin due to a change in a quiescent period when another liquid crystal material is used and a scanning voltage waveform is changed.

FIG. 7 is a diagram for explaining a conventional method of driving a ferroelectric liquid crystal display device, and is a waveform diagram showing a scanning voltage waveform and an information voltage waveform applied to a scanning electrode and an information electrode of the device. .

8 is a waveform chart showing a modified example of each drive waveform shown in FIG.

[Explanation of symbols]

 1 blanking pulse 2 kickback pulse 3 strobe pulse 4 TRIFLE pulse d pause period t strobe pulse application period

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H093 NA12 NB09 NB21 NB22 NB23 ND09 ND37 NF17 5C006 AF50 AF51 AF73 BA12 BB11 FA12 FA22 5C058 BA01 BB03 BB09 5C080 AA10 BB05 DD05 DD08 EE28 FF09 JJ04 JJ05

Claims (4)

[Claims] 1. A method of driving a ferroelectric liquid crystal display element in which a ferroelectric liquid crystal material is filled between a pair of substrates on each of which a scanning electrode and an information electrode are formed, wherein the element is arbitrarily displayed during a selection period. After applying a strobe pulse to the scan electrode to make a state, a pulse of the opposite polarity to the strobe pulse is applied to the scan electrode,
A method of driving a ferroelectric liquid crystal display device, further comprising providing a pause period in which a scanning voltage becomes 0 between the application period of the strobe pulse and the application period of the reverse polarity pulse. 2. The number of slots of an information voltage waveform corresponding to the sum of the application period of the strobe pulse and the pause period is:
2. The driving of the ferroelectric liquid crystal display device according to claim 1, wherein the application period and the pause period are set so as not to be an integral multiple of the number of slots of the information voltage waveform corresponding to the selection period. Method. 3. The method according to claim 1, wherein the pulse is of the opposite polarity so as to reduce the asymmetry of the charge caused by the strobe pulse without reducing the effect of the pulse of the opposite polarity. 3. The method according to claim 1, wherein a period is set. 4. The method according to claim 1, wherein a blanking pulse for resetting the display state of the device and a pulse having a polarity opposite to that of the blanking pulse are applied to the scan electrode before the application of the strobe pulse. 4. The method for driving a ferroelectric liquid crystal display element according to any one of 1 to 3.