JPS6167024A - Driving method of liquid crystal element - Google Patents

Abstract

PURPOSE:To obtain the driving method of a liquid crystal element which has fast responsibility and memory effect by applying a signal which orientates bistable liquid crystal and dichroic pigment in the 1st stable state and a signal which orientates them in the 2nd stable state to a data line corresponding to respective elements on a scanning line. CONSTITUTION:The liquid crystal enters either of the 1st and the 2nd optically stable states together with the dichroic pigment according to an applied electric field. Namely, a material which has a bistable state to the electric field, spe cially, liquid crystal having said properties is used. Chiral smectic liquid crystal having ferroelectricity is used most preferably and liquid crystal of chiral smectic C phase, H phase, F phase, I phase, and G phase is suitable. When a voltage higher than a specific threshold value is applied between electrodes on substrates 21 and 21', the spiral structure of liquid-crystal molecules 23 is untied and the orientation directions of liquid-crystal molecules 23 are so changed that all dipole moments 24 face in the electric field direction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving an optical modulation element such as a liquid crystal element, and more particularly to a time division driving method for a liquid crystal element used in an optical modulation element such as a display element or a shutter array.

Conventionally, scanning′? into a matrix of electrode groups and signal it electrode groups? and filling the finished compound between the electrodes,
2. Description of the Related Art Liquid crystal display elements that display images or information by forming a large number of pixels are well known.

The IIA method of this display element is scanning '1! Extremely detailed K
.

Time/minute M driving is adopted in which address signals are selectively applied in a periodic manner and a predetermined information signal is selectively applied in parallel to the signal electrode group in synchronization with the address signal. The driving method had a fatal drawback of 1rrJ as described below.

It is advisable to increase the pixel density and make the screen larger. Among conventional liquid crystals, most of them are practically used as display elements, for example, M, 5
By ahadt and JHslf-rich, 'Mupplie
d Physics Letters'', vol.

18, Fu 4 (1971, 2, 15), p, 127-1
28”voltage-Depen4snt
0ptical Activit7 of aτ
twisted Nematia Liquia Cry
T M (twisteL ne
matic) type of liquid crystal.This type of liquid crystal uses liquid crystal Ii! A twisted @a (helical structure) is formed in the thickness direction, and a structure in which the liquid crystal molecules are arranged parallel to each other on both electrode surfaces is formed. - When an electric field is applied, nematic liquid crystals with positive dielectric anisotropy are aligned in the direction of the electric field, resulting in optical modulation.

When this type of liquid crystal is used to construct a display element with a matrix 1 structure, the scanning distance and the signal electrode are both K x'
In the region '1m where N is selected (A selection point), TIL the liquid crystal molecules.
A voltage of I, 11 or more required to align perpendicularly to the polar plane is applied, and no voltage is applied to the region (non-selected point) K where neither the scanning electrode nor the signal electrode is selected, so that the liquid crystal molecules are aligned on the electrode plane. It maintains a stable parallel arrangement with respect to By arranging linear bond photons above and below such a liquid crystal cell in a cross nicol relationship with each other, no light will pass through selected points, but light will pass through non-selected points, making it possible to create an image element. It becomes possible. However, the matrix 'rIc
When a polar structure is configured, the scan electrode is selected and the signal electrode is not selected, or the scanning electrode is not selected and the signal [pole is selected] is located in the region (so-called 1 half selection point). The electric field gets hotter.The voltage applied to the selected point and
If the difference in voltage applied to the half-selection point is sufficiently large and the value for voltage 1 required to align liquid crystal molecules perpendicular to the electric field is set to a voltage value in between, the display element will always operate at i'E. That's why. However, in this method, scanning #
When the number of illuminations (N) is increased, the time during which an effective electric field is applied to one selected point while scanning the entire screen (one frame) (duty ratio) decreases at the rate of 1/N. I end up. For this reason, the effective voltage difference between the selection point and the ratio selection point when repeated scanning is performed becomes smaller as the number of scanning lines increases, resulting in a decrease in image contrast. Avoidance and crosstalk are serious drawbacks. This type of development requires liquid crystals that do not have bistability (the stable state is when the liquid crystal molecules are oriented horizontally with respect to the screen), and the liquid crystal molecules are only oriented directly while an electric field is effectively applied. This is an essentially unavoidable problem that arises when driving (i.e., repeated scanning) using the temporal accumulation effect (i.e., repeated scanning). In order to improve this point! [Volume averaging method, dual-frequency driving method, multiple matrix method, etc. have already been proposed, but all of them are insufficient, and large-sided display elements and high density cannot be achieved without a sufficient number of scanning lines. The current situation is that it has become a habitual trap because it cannot be increased. SUMMARY OF THE INVENTION An object of the present invention is to provide a novel variable-voltage element, particularly a method for driving a liquid crystal element, which solves the problems of the conventional liquid crystal display as described above.

Another object of the present invention is to provide a method for driving a liquid crystal element having high-speed response and a memory effect.

Another object of the present invention is to provide a method for driving a liquid crystal device having high density pixels.

Furthermore, another object of the present invention is to provide a method for driving a liquid crystal element that does not generate crosstalk and can form a bright display.

Such an object of the present invention is to provide a data line with a signal and a whistle that bring the bistable crystal and the dichroic dye into the first stable state r (T4 K orientation) in synchronization with the scanning signal applied to the scanning line. 2 on each +t!ii
This is achieved by a driving method of the A element, in which the voltage is applied in accordance with the element. ,Specifically, the drive@1 method of the present invention has a scan 1 death (
A method for driving a liquid crystal element having a structure in which a liquid crystal that is bistable with respect to an electric field and a dichroic dye are arranged between the scanning electrode group and the signal electrode group, and a dichroic dye is arranged between the scanning electrode group and the signal electrode group. In the step, between the selected scan 'a#& of the scanning electrode group and the selected signal electrode of the signal '1 electrode, the dichroic dye together with the bistable liquid crystal is in a first stable state. applying an orienting voltage VON+, and a voltage at which the dichroic dye along with the bistable liquid crystal is aligned in a second stable nK state between the selected scanning electrode and the unselected signal electrode of the signal electrode group; While applying voN2, between the unselected scanning electrodes of the scanning spreading group and the signal electrode group,
The dark voltage of the bistable liquid crystal -vth! (Second stable state!
2! (dark value voltage of I) and vth.

(referring to the a-value voltage in the first stable state) and applies the Kyudeno VQF F.
/C each zero voltage vOINovON2+vQP y K
The following relationship 2N'oyyl<1Voa+1. It is characterized by satisfying IVom21.

In a preferred embodiment of the invention, the Kukaho group and the Kukaho group are sequentially selected based on a scanning signal.

A selected liquid crystal element comprising a signal electrode group facing the pole group and selected based on a predetermined information signal, and a liquid crystal having bistable property against an electric field and a dichroic dye sandwiched therebetween. An electric signal V having different voltage polarities at phases t and 1 is applied to the scanning electrode.

(t) (phase including its phases t1 and t!'1JJ
In R, the maximum value is v, (t)max1Hk the small value is v
t (t) mtn), and the signal electrode group receives an electrical signal V with a different voltage depending on whether predetermined information exists or not.
.

and y, give /. That is, in the part where the information signal is present on the selected scanning electrode line, the phase 1+
At phase 11 (or 1.), a unidirectional 'electric field vt-v+ (t) is applied to the liquid crystal to bring it into a first stable state, and in the blank area, a second electric field is applied at phase 11 (or 1.). By applying an electric field vy-■+(t) in the opposite direction that provides a stable state and satisfying the following relationship, it is possible to make the liquid crystal element particularly stable.

'< l v+ (t) maw l / l Vt
11 < 1 v, (t)min l/I'/
l 11 < l 71 (t)maxl / I v
: 1 and'< l ■s (t) m1n I / l V;
1. Details of the specific example will be explained later with reference to section ①.

The liquid crystal used in the driving method of the present invention takes either the first optically stable state or the second optically stable state 1 depending on the electric field applied together with the dichroic dye, that is, it is bistable with respect to the electric field. A substance having a state, in particular a liquid crystal having such properties, is used.

As a liquid crystal having bistability that can be used in the driving method of the present invention, a chiral smectic liquid crystal having ferroelectricity is most preferable, and among these, a chiral smectic liquid crystal having ○ phase (8 mO*), *),? Phase (S
mF*), 1-phase (8m*), and G-phase (SmG*) liquid crystals are suitable. For this ferroelectric liquid crystal, =I
Jz:roσRNAI, DB P! IYSIQ, [T
KLKTTER8”56 (TP69) 1975 e
r Fe rr O61 @ ct r i '3Ii
1qu1dCr7stala J ;” Ap
plisd PhysicsI+ettsra” 5
6(11)19 $10, “8ubmicro E
lecondBistable F+1eatrqop
tic 8vitchlnq in LiqulOry
etals J; “Solid State Physics” 14 (141) 1
981 "Liquid Crystals", etc.9, and the ferroelectric liquid crystals disclosed therein can be used in the present invention.

More specifically, an example of the electrostatic liquid crystal compound used in the method of the present invention is decyloxybenzylidene-p'-amino-2-methylbutylcinnamese (DOBAMB
C) , hegysyloxypendyritene-p'-amino-
2-chloroprovir sinname) (HOBACPC)
and 4-O-(2-methyl)-butylresolcylidene-4'-octylaniline (MBRA8).

These liquid crystals may be used alone or in combination of two or more, or in combination with other smectic liquid crystals or cholesteric liquid crystals.
chiral nematic) may be mixed with night crystals.

A typical example of the dichroic pigment used in the present invention is as shown below.

In addition to these dichroic dyes, the present invention can also use helichromic dichroic dyes containing at least one chromophore moiety and at least one optically active moiety in the molecule. Chromophores include azo, azo-stilbene, be/dithiazolyl polyazo, azomethine, methi/,
merociani/, anotraquinone, methine-alien,
Tetrazine, oxadiazine, carbazole-azo, etc. can be used. In addition, the optically active moiety is an organic group having an asymmetric carbon atom, such as (@-2-methylalkyl group, (→-3-methylalkyl M, (+)-2-methylalkoxy group, (→- 5-methylalkoxy group, (
h)-5-methylshiff4henyl, (+1-α-methylbenzyl, (@-2-methylbutylbiphenyl, (→-
Examples include 2-methylbutylphenylthio and (e)-N-2-methylbutylaminonaphthalene.

Representative helichromic dichroic dyes are shown below. For these synthetic methods, see Ir! f Kaisho 59-9377
These dichroic dyes disclosed in Japanese Patent No. 7 are present in an amount of 0.1 to 10% by weight, preferably 1 to 10% by weight, based on smectate crystals, particularly chiral smectate liquid crystals exhibiting ferroelectricity.
It is dissolved in the smectic liquid crystal in the range of 5 times JK.

When constructing an element using these materials, the liquid crystal compound has a concentration of 8mO*, E1mU*, 13mF",
In order to maintain the temperature at a temperature of I'', 8 mG*, the element can be supported by a steel block or the like in which a heater is embedded, if necessary.

: Diagram X1 schematically depicts an example of a strongly charged liquid crystal cell. 21 and 21' are ntO, 8nO.

It is a substrate (glass plate) coated with a transparent electrode of ITO (Indium-Tin Oxle) 4, between which a liquid crystal molecular layer 22 is oriented perpendicularly to the glass surface. , 8m work *
, B, G* products and dichroic dye are enclosed. The thick line 23 represents liquid crystal molecules oriented with dichroic color zero, and this liquid crystal molecule 25t-jF
-1 It has a dipole moment (P) 24 in the direction perpendicular to its molecule. When a voltage higher than a certain threshold is applied between the electrodes on the substrates 21 and 21', the helical structure of the liquid crystal molecules 23 dissolves, and the liquid crystal molecules 25 A layer that changes the direction of orientation is formed. The liquid crystal molecule 23 has an elongated shape and exhibits refractive index field tropism in its long axis direction and short axis direction,
Therefore, for example, if you place one @photon above the glass surface,
It is easy to understand that a liquid whose optical properties change depending on the polarity of a voltage of 1:0M can be used as an optical modulation element (in this case, crossed nicol width photons may be placed above and below the glass surface).Furthermore, the liquid crystal When the cell thickness is made sufficiently thin (
For example &b1μ), even when no electric field is applied, the helical structure of the Ka crystal molecule becomes a non-helical structure with the dichroic dye, as shown in the second figure, and the dipole moment)P Alternatively, y is either upward (54) or downward (x4'). When such a cell is applied with an electric field E or 1 of different polarity above a certain threshold as shown in FIG. 2, the dipole moment E or 1 becomes 1! The direction is changed to upward 54 or downward 54' in accordance with the field vector,
Accordingly, both the dichroic dye and the Ka crystal molecule are either in the CGL stable state 35 or in the second stable state 53'.
Oriented to 10,000. Therefore, by placing one polarizer 1111C above the glass surface so that the optical axis is parallel to the alignment direction of the first stable state 53 or the second stable state 33', the optical Provides contrast.

There are six advantages of using such a strong Wst late crystal as an optical modulation element. The first K is that the response speed is extremely fast, and the second is that the alignment of liquid crystal molecules has bistability. , 42 will be explained with reference to FIG. 2, for example. When the electric field 2 is applied, the sheet crystal molecules are oriented in the first stable direction 453, but this state remains stable even when the electric field is turned off.

Also, 7 in the opposite direction! When the L field Z' is applied, the liquid crystal molecules become @
The molecules are oriented in the stable state 55' of 2 and change their orientation, but they remain in this state even after cutting the stain boundary. Also, the electric field I applied has a certain threshold value of ¥c! ! In order to effectively achieve such high response speed and memory effect, it is preferable that the cell be as thin as possible, and generally A suitable value is 0.5 μ to 20 μ, particularly 1 μ to 5 μ. A liquid crystal electromagnetic device having a matrix electrode structure using ferroelectric liquid crystals of this type is disclosed, for example, by Clark and Ragabal in US Pat. No. 4,567,924. This method is proposed in the specification of the No. 2003 patent.At tπ3, only one S source plate is required and a bright display can be obtained.

Preferred specific example of the driving method of the present invention (example of ferroelectric liquid crystal)
will be explained using FIGS. 3(A)-(B).

FIG. 3(A)-(a) is a schematic diagram of the electrode arrangement of a cell 11 having a matrix electrode structure in which a dichroic dye and a ferroelectric liquid crystal compound stool (not shown) are sandwiched in the middle. . 1
2 is a scanning electrode group, and 15 is a signal electrode group. Maki 3
Figure (A)-(1)) and factor-(((ri) are respectively the selected scan electrode 12(s)K given m and the other scan electrodes (unselected scan electrodes) 12(n)K The applied electrical signals are shown in Figure 5 (A)-C'Fr') and (
A) - (a) are respectively achieved signal electrodes 15 (s
) and the unselected signal i-pole 13 (
n) represents an electrical signal applied to gXS diagram (A)
-(b) to (A)-(1!1)K, the horizontal axis represents time and the axis represents voltage. For example, when displaying a moving image, the scanning electrode groups 12 are sequentially and periodically selected. Now, the opening voltage for giving the first stable state of a bistable liquid crystal cell having a dichroic dye is vth,
and a threshold g1. for providing the second stable state. T! When L king is -v th, the selected scan electrode 12 (s
) The electrode signal given by K is 5@S (mu) - (1)
) As shown in the phase (time) 1-t, V,
At phase (time) tt, it is an alternating voltage such that -v. When electrical signals having a plurality of phase intervals with different voltages are applied to the scanning electrodes selected in this way, the transition between the first or second stable state of the liquid crystal corresponding to the optical "bright" or "dark" state is achieved. The important effect is that a change in state can be caused quickly.

On the other hand, whispering other scans 12(n) is: Jr, 3■
As shown in (A)-(C), the ground is prone and the hypochondrium signal O is detected. In addition, the selected signal electrode 15(s)
The electrical signal given by K is as shown in FIG. 5(A)-(a).<v! and signal electrode 1!1 which is not selected
The drowsiness signal given to (n) is Hama 5 factor (A) - (11
) K As shown, -V. In the above, each voltage value is set to a desired value that satisfies the following relationship.

"t * (vt - vt) < V th I < Vt
+Vt and -(V, +V, )(-V th.

'<-v! + (vs −vt) ・Each pixel when such a blur signal is given, that is, ii'ri + element A shown in FIG. 5(A)-(a) K,
The voltage waveforms applied to B, O, and Dl, respectively, are expressed as (a), (1)), (C) Th and (,
Shown in i). That is, tM5 diagram CB) −(a) ~
As is clearer from (a), in the phase t, a voltage v1-1-v exceeding the j-value vth1 is applied to the pixel on the selected scanning line. In addition, for pixel B existing on the same scanning line, at phase t1, the rd value -v th,
A voltage exceeding −(vt+v) is applied. Therefore, depending on whether or not a signal electrode is selected on the selected scanning electrode line, if selected, the 11th crystal molecule
If no selection is made, the orientation is adjusted to a second stable state. In any case, it has nothing to do with the previous history of each pixel.

On the other hand, the voltage applied to pixels C and DK is 30th (B)
(C) and (L)K As shown, on the unselected scan line, the voltage applied to all pixels 0 and D is V! or -v, neither of which exceeds the threshold voltage. Therefore, the liquid crystal molecules in each pixel 0 and D maintain the orientation corresponding to the signal state when scanned last time without changing the orientation state.In other words, when the scanning electrode is selected and the 1st After a line's worth of signals is written, the signal state can be maintained until the next frame is selected. Therefore,
Even if the number of scanning electrodes increases, the actual duty ratio remains the same and there is no reduction in contrast at all. At this time, v
l and V.

The value of the phase (1m+1.) = τ depends on the liquid crystal material used and the thickness of the cell, but
Normally S volt ~ 7o volt, Ojμsec ~ 2 m5
A range of ec is used. Here, in the method of the present invention, 1
The hypochondriacal signal given to the selected scan'TE pole is
from the stable state n (assumed to be in the "bright" state when converted to an optical signal) to the second stable state! For example, the selected scan electrode may be exposed to +V , to -v1, providing an alternating voltage signal.

Further, the voltages applied to the signal electrodes are different from each other in order to specify the bright or dark state.

Now, in the above, the operation and driving method of the bistable, ferroelectric liquid 1 has been described based on mostly ideal conditions. For example, even though it is called a bistable liquid crystal, it does not actually remain in one stable state for an infinitely long time in the absence of an electric field. To give a more specific example,
Warm! At present, at 70° C., in the case of a layer of ferroelectric liquid crystal DOBAMBC having a thickness of 5 μm or more, a portion of the helical structure initially remains in the smc* phase. When an electric field (for example, +450,715 μm) in one direction in the layer thickness direction is applied to this, the helical structure is completely unwound, and the bistable liquid crystal along with the dichroic dye transitions to an in-plane-collar orientation state. After this, when the state is returned to the field-free state, the released molecules gradually return to the helical structure. Contrast decreases. The speed at which this unidirectional stable egg is released strongly depends on the surface condition (surface material, surface treatment, etc.) of the pair of substrates that sandwich the liquid crystal material and the thickness of the liquid crystal layer. In addition, in the previous explanation, the threshold voltages vth, b, and vth necessary for transferring to the one-way stable period are -
Although this value has been set as a single value, this value also strongly depends on the requirements such as the surface condition of the substrate, so there are large variations depending on the individual cells. Furthermore, the dark value 1 voltage depends on the time of tail pressure application, and as fK becomes longer when voltage is applied, the threshold voltage tends to decrease. There is a risk that a transition will occur between the two stable states, resulting in crosstalk.

From the above, we can actually create an optical modulation element stably,
Kakeru! 11h, at one choice point r, (', 1 and the voltage 7 oriented to the second stable state).
It is preferable to set the values of voltage v□yy applied at 0M1 and voN2 and non-selected points, respectively, as far as possible from the average tale voltages thl and Vth2. , or when considering the variation within the element, 1yOyyl(i
It was confirmed that it is preferable for the values of IVo*+I and 1VoNzl to be at least twice the value of ') in order to obtain stability f.

In addition, when such voltage application conditions are realized using the driving method explained in FIG. The voltage applied to the corresponding pixel without information due to the electrode (Fig. 5(B)-(1))
), the phase t.

(The values of tlE value 1 v, -v, and H are also separated by a light minute from the value of Ks vON+, similar to the voltage vO?F applied to non-selected pixels, and are especially less than 1/1.2 of the old value of Vo. Therefore, corresponding to the example of Fig. 5, the condition for this is 1<lv+ (t) l/ IVI l<10. The applied voltage and the electric signal given to each electrode need not be symmetrical or stepped.In order to express it generally, including such cases, within the position F@t, +t, Let the maximum value of the electrical signal (voltage due to the difference from the ground potential) that can be generated by 7Jl with the scanning of
′ corresponding to Sui/invasion applied to Tan′π1〉! When the electric signal vt, the electric signal corresponding to the no information applied to the signal EtiK that is not selected by J3 (both are voltages due to the difference from the ground potential) are y, /, it is stable that the following equation is satisfied. Button preferred for actuation.

1< l vt (t) mail / l Vt I
<101<Ivs (t)min I/lvy l<1
01<lV+ (t)max l,/lv, +<1
.

and 1<lV+ (t) m1n I/lv’t l<+.

Based on the embodiment explained in Fig. 45, 7! ! Applied to the selection point (between the selection signal north pole and the selected or non-selected scan electrode) when the ratio of the electric signal V applied to the torrent electrode and the electric signal ±V applied to the signal IK pole is changed. For example, the fifth factor (B
) - Phase 11 of (a) (or Fig. 5 CB) -
(b) Phase 11) Applied voltage I V@ -v,
FIG. 4 is a graph that shows the ratio of 1 to 1 (both are expressed as absolute values). As you can see from this graph, 1 ratio = lvt/vt 10 value is 1 especially 1 especially 1 (
K (preferably in the range of 10).

In order for the driving method of the present invention to be effectively achieved, K must be such that the electrical signals applied to the scanning poles or signal electrodes are not necessarily the same as those shown in FIGS. (a
) to (a) It is obvious that the signal does not have to be a double-line rectangular wave signal as explained in K. For example, it is also possible to drive with a sine wave or a triangular wave, as long as an effective time span is provided.

The fifth factor is a schematic plan view of a liquid crystal-source shutter, which is a row of preferred application objects of the driving method of the present invention. Here, 41 is a pixel, and the electrodes on both sides of this part are made of transparent material. The matrix electrode includes the scanning side electrode group 42 and the signal electrode! It is configured with IP45.

[Brief explanation of drawings]

Jl[1 is a perspective view schematically showing an original device having a chiral smectoid phase liquid crystal. FIG. 2 is a perspective view schematically showing the bistability of a liquid crystal element used in the method of the present invention. ficS diagram (A) (a) is a plane (■) schematically showing the electrode arrangement state of a liquid crystal element used in the th driving method of the present invention. , FIG. 3(A) (13) is a waveform diagram of an electric signal applied to a selected scanning electrode. Scene 3 (Mu) (C) #
:j1 is a signal waveform diagram applied to the unselected scanning voltage NK. Figure 43 (A) (a) shows the conventional signal waveform factor applied to the selected signal electrode. Figure 5 (A) (6
) is an information signal waveform diagram to which the signal 'ζff1K which is not selected is added. The fifth factor (B) (,!L) is a waveform diagram of the voltage applied to the liquid crystal of the pixel. Figure 5 (B)
(b) is a waveform diagram of the voltage applied to the liquid crystal of pixel B. -85-CB) (C) is within the waveform of the voltage applied to the liquid crystal of pixel C. 43 causes CB) (, i) H
FIG. 3 is a waveform diagram of a voltage applied to liquid AK for one pixel. The fourth element is the electrical signal V applied to the scanning electrode. 2 is a graph showing the change in vomiting stability due to an absolute change in the ratio of the electric signal ±V applied to the signal electrode and the electric signal ±V applied to the signal electrode. FIG. 5 is a schematic plane diagram of a liquid crystal and a YT Las Chatter as an example of a preferable application target of the driving method of the present invention. 11...Liquid crystal element 12...Scanning voltage detail 12(al...Selected scan 1 is switched to pole 12(nl...
・Unselected trace i' to pole 13...Signal electric frame details 15(a)...Selected signal electrode 1! +(n)...Signal electrode 33 not selected...
・Liquid crystal 55' aligned in the first stable state...Second
Stable GLC-oriented liquid crystal 34...Upward dipole moment P34'...Downward dipole moment y41, -, pixel 42...Scanning electrode group 43...Select electrode group Fig. 3 (A) -(Vt+Vz)

Claims (6)

[Claims] (1) In synchronization with the scanning signal applied to the scanning line, a signal for orienting the bistable liquid crystal and the dichroic dye to the first stable state and a signal for orienting the dichroic dye to the second stable state are applied to the data line during scanning. A method for driving a liquid crystal element characterized by applying voltage in correspondence to each pixel on a line. (2) The method for driving a liquid crystal element according to claim 1, wherein the bistable liquid crystal is a ferroelectric liquid crystal. (3) The method for driving a liquid crystal element according to claim 2, wherein the ferroelectric liquid crystal is a chiral smect liquid crystal. (4) The method for driving a liquid crystal device according to claim 3, wherein the chiral smect liquid crystal has a liquid crystal phase with a non-helical structure. (5) The chiral smectate liquid crystal has a C phase, an H phase,
5. The method of driving a liquid crystal element according to claim 3 or 4, wherein the liquid crystal element is F phase, I phase or R phase. (6) The method for driving a liquid crystal element according to claim 1, wherein the dichroic dye is a helichromic dichroic dye.