JPS61243886A - Liquid crystal device for time sharing deive - Google Patents

Abstract

PURPOSE:To provide a liquid crystal device for a time sharing drive capable of preventing inversion and holding picture elements in a written state for a predetermined period of time, which comprises picture elements having a specific liquid crystal compd. CONSTITUTION:Picture elements (e.g.: A and B) of a cell 31 comprising a plurality of pairs of facing electrodes provided on substrates and a liquid crystal compd. of the formula (wherein R is a 1-8C alkyl or alkoxy; m is an integer of 0 or 1; when m is 0, R' is a 1-18C alkyl; and when m is 1, R' is a 1-18C alkyl or alkoxy) which is in a bistable state or liquid crystal compd. compsn. containing the above liquid crystal compd. are arranged in a plurality of lines. A time sharing drive is conducted as follows. The picture elements formed by intersections of electrodes S1-S5 of a group of scanning electrodes 32 electrodes I1-I5 of a group of signal electrodes 33 are selected by the scanning electrodes, and the application of a voltage is made to write signals by one line, e.g., causing A to be in a light state and B to be a dark state. At this time, the written state of the picture elements are held until writing of one frame is completed and subsequent selection is effected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a ferroelectric liquid crystal device in a bistable state, and more specifically, to a ferroelectric liquid crystal device that uses a memory drive method that maintains a written state during a frame or l-field period. This invention relates to a time-division driving liquid crystal element.

[Prior art] Examples of conventional liquid crystal elements include M, Shut CM,
5chadt) and W. Helfrich (W.
“Applied Physics Letters” by He1frich
tters'') Volume 18, No. 4 (February 15, 1971
“Voltage Dependant 3 Optical Activities”, pp. 127-12B.
A Twisted Nematic Liquid Crystal” (Voltage Dependent 0ptic
al Activity of aTwisted N
Twisted nematic (twisted n
(ematic) devices using liquid crystals are known. This ↑N liquid crystal has the problem of generating crosstalk during time-division driving using a matrix electrode structure with high pixel density, so the number of pixels is limited. or.

A display element is known in which a switching element using a thin film transistor is connected to each pixel, and each pixel is switched. However, the process of forming the thin film transistor on the substrate is extremely complicated, and it is difficult to create a display element with a large area. There are some difficult issues.

Clark and Lage have proposed ways to improve the drawbacks of conventional liquid crystal devices.
rwall) shows that the helical structure of 1 ferroelectric liquid crystal can be unraveled by making the film thickness of 1 ferroelectric liquid crystal less than 5 times its helical pitch, and as a result, bistability is expressed. For example, it is published in US Pat. No. 43Et7924.

As a liquid crystal having this bistability, a ferroelectric liquid crystal having a chiral smectic C phase (Sac or H phase (SmH)) is generally used. This liquid crystal has a first optical stability against an electric field. It has a bistable state consisting of a state and a second optically stable state.

Therefore, unlike the optical modulation element used in the above-mentioned TN type liquid crystal, for example, the liquid crystal is oriented in a first optically stable state with respect to one electric field vector, and in a second optically stable state with respect to the other electric field vector. The liquid crystal is aligned in an optically stable state. Furthermore, this type of liquid crystal has the property of very quickly taking one of the above two stable states in response to an applied electric field, and maintaining that state when no electric field is applied.

By utilizing such properties, many of the problems of the conventional TN type device described above can be significantly improved.

[Problem to be Solved by the Invention 1] However, when the above-mentioned bistable liquid crystal element is used to perform time-division drive using the memory drive method described later, pixels written in accordance with information signals on the screen Some of these methods have the problem of causing an inversion phenomenon of written pixels due to changing the stable alignment state from the liquid crystal alignment direction during writing to the other liquid crystal alignment direction. This is, for example, a phenomenon in which a pixel written as a "white" signal on the screen is inverted to a "black" state. The occurrence of such an inversion phenomenon actually makes it difficult to apply this ferroelectric liquid crystal element to a display device.

It is an object of the present invention to prevent the above-mentioned inversion phenomenon and change the written state of pixels written in accordance with information signals in one frame or one frame.
An object of the present invention is to provide a time-division driving liquid crystal element that can be maintained during a field period.

[Means for Solving the Problems] and [Operation] The present invention provides a pair of opposing electrodes and a compound represented by the general formula (I) in a bistable state.
Pixels having a liquid crystal compound or a liquid crystal composition containing the same represented by #i were arranged in several rows, and a writing signal was applied to each row of pixels in the plurality of rows, and the writing signal was applied. The present invention is characterized by a time-division drive liquid crystal element that performs time-division driving in which the write state of pixels in a row is maintained until a write signal of the next cycle is applied.

(In the above general formula, R is an alkyl group or an alkoxy group having 1 to 18 carbon atoms, l is O or 1, and 1=
When 0, R' is an alkyl group having 1 to 18 carbon atoms, and when m=l, R' is an alkyl group or an alkoxy group having 1 to 18 carbon atoms. The liquid crystal composition contained has good threshold characteristics as a ferroelectric liquid crystal, and by applying it to a liquid crystal element, the above-mentioned inversion phenomenon can be effectively prevented.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

The liquid crystal used in the present invention has ferroelectricity, and specifically, the liquid crystal has chiral smectifference C phase (Sac phase).
H phase (S cod, I phase (Sm 1, J phase (S + sJ◆),
A liquid crystal having a phase (S), a G phase (SmG), or an F phase (Sd'') can be used.

The liquid 1 compound represented by the above general formula (I) that can be used in the ferroelectric liquid crystal element of the present invention is as follows.

It can be easily obtained by the following synthesis method, and specific examples obtained by the synthesis are shown in Synthesis Examples 1 to 18 and Tables 1 to 3 below.

The liquid crystal compound used in the present invention represented by general formula (I) is 1
For example, a 2,3-dicyanopyrazine derivative represented by the general formula (■): (wherein R is a furkyl group or an alkoxy group having 1 to 18 carbon atoms) is hydrolyzed and then decarboxylated.

A 2-carboxypyrazine derivative represented by the general formula (■): is obtained, which is halogenated to form an acid halide, and the general formula (■): (Formula, middle layer is 0 or 1, and 1 layer = O When R' is an alkyl group having 1 to 18 carbon atoms, and when R' is
represents an alkyl group or an alkoxy group having 1 to 18 carbon atoms) It can be produced by reacting and esterifying a compound represented by:

The 2,3-dicyanopyrazine derivative represented by the general formula (II) can be produced by a known production method [Tadataka Tsuda et al., Journal of the Japanese Society of Agricultural Chemistry, Vol. 52, p. 213 (1978
year)].

Next, the present invention will be explained in more detail by giving synthesis examples.

In addition, in the following synthesis examples, the phase transition temperature is DEC(
The measurement was carried out using a Seiko Electronics SSC580DS), and a liquid crystal glass plate with the size of a moon was inserted into a temperature-controlled copper block, and the liquid crystal was observed using a polarizing microscope.

Synthesis Example 1 5-(p-octyloxyphenyl)pyrazine-2-carboxylic acid p-octyloxyphenyl ester Selenium dioxide 11.4 g (0.1 moi'), dioxane 100 ml! , mix 2+f of water and heat at 70-75°C.
After stirring for an hour, p-octyloxyacetophenone 2
A solution of 4.8 g (0°1 moi')-dioxane (60 μl) was added. After refluxing for 2 hours, it was cooled and the precipitated metallic selenium was filtered. To the filtrate was added 10.8 g of DAMN (0,
Add 1 moIl) and 3.0 p of acetic acid, and heat to 80-93°C.
After the reaction was refluxed for 2 hours, the mixture was cooled and filtered, and the filtrate was concentrated to obtain a crude product. After recrystallization from hexane, 2? ,
2g (82% yield) of product was obtained. Melting point 79℃,
ERp c+s-1: 2245 (C!N).

Elemental analysis Calculated value as C20H22N40: C71,83H8,83N 113.75 Actual value: C72,02H8,75N 18.55 (II
) Synthesis of 5-(p-octyloxyphenyl)pyrazine-2,3-dicarboxylic acid 5-(p-octyloxyphenyl)pyrazine-2,3
-Dicarbonitrile (8.7g, 0.028moi'
) with sodium hydroxide (15g, 0.375 aid
)-water (800 ml) and stirred at 95°C for 3 hours. After the reaction, concentrated hydrochloric acid was added to acidify the reaction solution, and the precipitate was filtered. Washed with 80 sjj water 5 times,
After vacuum drying, 8.1 g (84% yield) of product was obtained.

After recrystallization from ethanol-water, melting point is 163°C. IRy
cm-1: 3400-2550 (OH), 173
0. IEi95(C-0).

Elemental analysis C? Calculated value as oHzN20s: C84,50HEi, 50N 7.52 Actual value: C134,52H13,70N 7.385-
(p-octyloxyphenyl)pyrazine-2,3-carboxylic acid (8.1 g, 0.0218 moR) was placed in dichlorobenzene (100 mj) and the oil bath was heated to 1130 ml.
The temperature was set to 0.degree. C. and stirred for 3.5 hours. - After standing overnight, the precipitate was filtered and diluted with hexane 6011R to obtain 4.1 g of product. After recrystallization from ethanol-water, melting point 18
5℃, decomposition point 190℃, IRF cm-1: 340
0-2500 (OH), 1880 (C-0).

Elemental analysis Calculated value as Cl9H24N203: C
89,48H7,37N 8.53 Actual value: C139
,135H7,35N 8.38(IT) Esterified 5-(p-octyloxyphenyl)pyrazine-2-,
l'J, IL/Ho7m (4,10g, 0.01
25a+oi') in thionyl chloride 80■P,
After refluxing for 0 hours, excess thionyl chloride was distilled off under reduced pressure, and the residue was dissolved in 250 rall of toluene. The toluene solution was washed four times with 70 layers of water P, dried over magnesium sulfate, and then the solvent was distilled off. The residue was washed with hexane, placed in acetone (100 mjJ), cooled to 5°C, and mixed with 1.77 g of p-octyloxyphenol while stirring.
g (7.98 gmol), sodium hydroxide 0.
3B.

A mixed solution of (9 parts, 10 parts of water) and 20 parts of acetone was added dropwise over 25 minutes. Then, at 5℃
After stirring for an hour, the reaction solution was filtered. Dissolve the precipitate in toluene (400ml) and add 0.5N sodium hydroxide aqueous solution 15G fat! Wash with 200ml of water!
After washing the toluene solution three times with water and drying the toluene solution with magnesium sulfate, the solvent was distilled off. The residue was washed with hexane and recrystallized from toluene-hexane.

1.98 g (3% yield at 2°C) of product was obtained.

IRF am-1: 1730 (C-0).

Elemental analysis 033 Ha s N20s.

Calculated value: C74,40H8,33N 5.213 Actual value: C74,55H8,51N 5.09MMR5p
pm (CDCI:+): 8.40 (d, IH, J-
1.5Hz), 13.15(d, 11.J=1.5
Hz), 8.11(d, 2H).

7.08 (d, 2H), 7.18 (d, 2H), 13.
90 (d, 2H), 4.04 (t, 2H), 3.138
(t.

2H), 1.90 to 0.70 (m, 308).

Synthesis examples 2 to 19 In the same manner as in Synthesis Example 1, the compounds shown in Table 1 were obtained.

The results of elemental analysis of the compounds obtained in Synthesis Examples 1 to 19 above are shown in Table 1, the MMR and IR data are shown in Table 2, and the phase transition temperatures of the compounds obtained in Synthesis Examples 1 to 19 are shown in Table 3. show.

In the present invention, a ferroelectric chiral smectic liquid crystal can be easily obtained by introducing an optically active group into the structure represented by the general formula (I).In the present invention, the ferroelectric liquid crystal represented by the general formula (I) Chiral smectic liquid crystal is N.

Ferroelectric smectic liquid crystals are driven by simple matrix electrodes because they have excellent threshold characteristics for electric field response when used as display elements as shown by N. Clark et al. When used in displays, it is possible to prevent crosstalk and provide good contrast. These characteristics also apply to liquid crystal compositions containing the liquid crystal compound of the present invention, and when using ferroelectric smectic liquid crystals as high-definition, large-screen display elements, the liquid crystal compound of the present invention is particularly effective. Are better.

On the other hand, compounds of the present invention that do not contain optically active groups in their structure and have a Sac phase (for example, p-octyloxyphenyl 5-(p-octyloxyphenyl) pyrazine-
A liquid crystal composition obtained by mixing a liquid crystal compound having a chiral smectate phase as shown in Table 1 with 2-carboxylate) can be used as a ferroelectric chiral smectate liquid crystal. Instead of mixing a liquid crystal compound having a 0 ferroelectric chiral smecte ink phase, a liquid crystal compound containing an optically active group as shown in Table 1 but not exhibiting a chiral smecte ink phase, or simply A liquid crystal composition containing a liquid crystal compound containing an optically active group can also be used as a ferroelectric smectic liquid crystal. The ferroelectric chiral smectic liquid crystal composition thus prepared exhibited excellent threshold properties conferred by the basic framework presented in the present invention.

As mentioned above, the liquid crystal compound used in the present invention can be used alone as a material for a ferroelectric liquid crystal element, but when mixed with other components to form a composition with improved performance of a ferroelectric liquid crystal element, The content of the compound represented by the general formula CI) in the composition is preferably 1% by weight to 8θ% by weight, more preferably 5% by weight to 95% by weight.

At this time, other liquid crystal compounds that can form a mixed ferroelectric liquid crystal composition with the liquid crystal compound used in the present invention are shown in Tables 4 and 5.

Table-4 ζ -COOCH2CHC2Hs Zero←---Cholesderic phase←-110,000 phase/' Table-5 (A) Cholesteryl propionate (B) Cholesteryl nonanate (C) Cholesteryl palmitate CD) Cholesteryl nonanate 4-(2''-Methylbutyl)-4'-cyanobiphenyl-cyanobiphenyl-(2-methylbutyl)aniline When constructing an element using these materials, the liquid crystal compound should be in the Sac'' phase or 5szH phase. In order to maintain the device at a certain temperature, the device can be supported by a copper block or the like in which a heater is embedded, if necessary.

FIG. 1 schematically depicts an example of a ferroelectric liquid crystal cell. 11 and 11' are In2O3, SnO+ and I
A substrate (glass plate) coated with a transparent electrode such as TO (Indium-Tin-Owide), between which a liquid crystal molecular layer 12 is oriented perpendicular to the glass surface.
''' phase liquid crystal is sealed. The thick line 13 represents the liquid crystal molecule, and this liquid crystal molecule 13 has a dipole moment (P) 14 in the direction perpendicular to the molecule. When a voltage higher than a certain threshold is applied between the electrodes on the substrates 11 and 11', the helical structure of the liquid crystal molecules 13 is unraveled, and the dipole moment) (P) 14 is arranged so that all of the liquid crystal molecules are oriented in the direction of the electric field. 13 can change the alignment direction.The liquid crystal molecules 13 have an elongated shape,
Liquid crystal optics exhibit refractive index anisotropy in the long axis direction and short axis direction, and therefore, if polarizers are placed above and below the glass surface in a crossed nicol positional relationship, the optical properties change depending on the polarity of voltage application. It is easily understood that this serves as a modulation element. Furthermore, when the thickness of the liquid crystal cell is made sufficiently thin (for example, IIL), the helical structure of the liquid crystal molecules unwinds and becomes a non-helical structure even when no electric field is applied, as shown in Figure 2, and its dipole moment increases. P or P' is either upward (24) or downward (24'). When an electric field E or E' with a different polarity above a certain threshold value is applied to such a cell as shown in FIG. ', and accordingly, the liquid crystal molecules are aligned in either the first stable state 23 or the second stable state 23'.

There are two advantages to using such a ferroelectric liquid crystal as an optical modulation element. Firstly, the response speed is extremely fast, and secondly, the alignment of liquid crystal molecules has bistability. To explain the second point with reference to FIG. 2, for example, when the electric field E is applied, the liquid crystal molecules are oriented in a first stable state 23, and this state remains stable even when the electric field is turned off. When an electric field E' in the opposite direction is applied, the liquid crystal molecules are oriented to a second stable state 23' and change their orientation, but they remain in this state even after the electric field is turned off.

Further, as long as the applied electric field E does not exceed a certain threshold value, each orientation state is maintained. In order to effectively realize such fast response speed and bistability, it is preferable that the cell be as thin as possible, and generally, 0
．． 5. ˜20 liters, especially 1% to 5 liters are suitable.

Next, a specific example of a method for driving a ferroelectric liquid crystal will be explained using FIGS. 3 to 5.

FIG. 3 is a schematic diagram of a cell 31 having a matrix electrode structure in which a ferroelectric liquid crystal compound (not shown) is sandwiched between. 32 is a scanning electrode group, and 33 is a signal electrode group. First, the case where scanning electrode S1 is selected will be described. FIG. 4(a) and FIG. 4(b) are scanning signals, which are electric signals applied to the selected scanning electrode Sl and other scanning electrodes (unselected scanning electrodes), respectively.
It shows electrical signals applied to S2, S3 *S4... FIG. 4(C) and FIG. 4(d) show information signals from selected signal electrodes I+ and I3, respectively.
, I5 and the unselected signal electrode I2. It shows the electrical signal received by I4.

In FIGS. 4 and 5, the horizontal axis represents time and the vertical axis represents voltage. For example, when displaying a moving image, the scanning electrode groups 32 are sequentially and periodically selected.

Now, the threshold voltage for achieving the first stable state of a liquid crystal cell having bistability for a predetermined voltage application time tl or t2 is set to -V th+, and the second stable state is set to t.
Assuming that the threshold voltage for scanning is +Vth2, the electrode signal given to the selected scanning electrode 32 (S+) is
As shown in figure (a), at phase (time) 1+, 2V
is an alternating voltage that becomes -2V at phase (time) t2. When electrical signals having multiple phase intervals with mutually different voltages are applied to the scanning electrodes selected in this way, the difference between the first or second stable state of the liquid crystal corresponding to the optical "dark" or "bright" state is generated. The important effect is that the state change can be caused quickly.

On the other hand, the other scanning electrodes S2 to S5... are shown in FIG.
As shown in b), it is in a grounded state and the electrical signal is O. Also, the selected signal electrode work 1.

The electric signal applied to I3+I5 is v as shown in FIG. 4(C), and the unselected signal electrode I21
As shown in FIG. 4(d), the electric signals applied to the terminals 14 and 14 are each set to a desired value that satisfies the following relationship in the range of 0 or more, where <-V.

V<Vth2<3V -3V<-Vth, <-V Among the pixels when such an electric signal is applied, for example, the voltage waveforms applied to pixels A and B in FIG. As shown in Figures (a) and (b), namely, Figure 5 (
As is clear from a) and (b), a voltage of 3 V exceeding the threshold V th2 is applied to the pixel A on the selected scanning line at phase t2. Furthermore, a voltage -3v exceeding the threshold value -vth is applied to the pixel B existing on the same scanning line at phase t1. Therefore, depending on whether a signal electrode is selected on the selected scanning electrode line, if one is selected, the liquid crystal molecules are aligned in the first stable state, and if not selected, the liquid crystal molecules are aligned in the first stable state. Align the orientation to the stable state of 2.

On the other hand, as shown in FIGS. 5C and 5D, on unselected scanning lines, the voltage applied to all pixels is V or -■, neither of which exceeds the threshold voltage. Therefore, the liquid crystal molecules in each pixel other than the selected scanning line maintain the orientation corresponding to the signal state at the time of the previous scan without changing the orientation state. That is, when a scanning electrode is selected, a signal for one line is written, and the signal state can be maintained until the next selection after one frame is completed. Therefore, even if the number of scanning electrodes increases, the actual duty ratio does not change and the contrast does not deteriorate at all.

Next, let us consider the problems that may actually occur when the device is driven as a display device.

In FIG. 3, scanning electrode S! Among the pixels formed at the intersections of ~S5... and signal electrodes 1~I5..., the pixels in the shaded area correspond to the "bright" state, and the pixels shown in white correspond to the "dark" state. do. Now, paying attention to the display on the signal electrode Il in FIG. 3, the pixel (A) corresponding to the scanning electrode S1
, it is in the "bright" state, and all other pixels (B) are in the "dark" state.

As an example of the driving method in this case, the scanning signal and the signal electrode ■
FIG. 6 is a time-series representation of the information signal applied to pixel A and the voltage applied to pixel A.

For example, when driving as shown in Fig. 6, ``When the scanning signal SI is scanned, a voltage of 3V exceeding the threshold value Vth2 is applied to the pixel A at time t2, regardless of the previous history. , pixel A transitions (switches) to a stable state in one direction, that is, a "bright" state, and then 82 to S5...
While * is being scanned, a voltage <-V continues to be applied as shown in FIG. 6, but since this does not exceed the threshold value -Vth+, pixel A should be able to maintain a "bright" state. In reality, when displaying information in which one signal (corresponding to "dark" in this case) is continuously given on one signal electrode, the number of scanning lines is extremely large and high-speed driving is required. However, by using the above-mentioned specific liquid crystal compound or a liquid crystal composition containing the same, such a reversal phenomenon can be completely prevented.

Furthermore, in the present invention, in order to prevent the above-mentioned reversal phenomenon, it is preferable to provide an insulating film formed of an insulating material on at least one of the opposing electrodes constituting the liquid crystal cell.

The insulating materials used in this case are not particularly limited, but include silicon nitride, hydrogen-containing silicon nitride, silicon carbide, hydrogen-containing silicon nitride, silicon oxide, boron nitride, Inorganic insulating materials such as hydrogen-containing boron nitride, cerium oxide, aluminum oxide, zirconium oxide, titanium oxide and magnesium fluoride, or polyvinyl alcohol, polyimide, polyamideimide, polyesterimide, polyparaxylylene, polyester, polycarbonate,
Organic insulating materials such as polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin, and photoresist resin are used as the insulating film. The film thickness of these insulating films is 5000A or less, preferably 10A or less.
0 A to 5000 A, especially 5008 to 30 QOA are suitable.

[Example] Hereinafter, the present invention will be explained according to examples.

Example 1 A polyimide film having a film thickness of 100 OA (5 wt% of polyamic acid resin from a combination of pyromellitic anhydride and 4,4'-diaminodiphenyl ether) was formed on each of the opposing matrix electrodes formed of crossed strips of ITO. ,
A solution of N-methylpyrrolidone (formed by a heating ring-closing reaction at a temperature of 250° C.) was applied, and the surfaces of this polyimide film were rubbed so as to be parallel to each other, thereby creating a cell having a cell thickness of 1JL.

Next, 2-methylbutyloxyphenyl 5-(octyloxyphenyl)pyrazine-2-carbonate was injected into the above-mentioned cell by a vacuum injection method under the Tokichi phase, and the cell was sealed. After that, Sac
” created a liquid crystal cell.

A crossed Nicol polarizer and an analyzer were arranged on both sides of this liquid crystal cell, and a signal having the waveform shown in FIGS. 4 and 5 was applied between opposing matrix electrodes at 125° C. At this time, the scanning signal had an alternating waveform of +8 volts and 18 volts as shown in FIG. 4(a), and the write information was set to +4 volts and 14 volts, respectively.

Further, the period of one frame was set to 30 layers/sec.

As a result, even when this liquid crystal element was subjected to the above-mentioned memory-driven time-division driving, the written state was not reversed and a normal moving image display was obtained.

Examples 2 to 4 In place of the liquid crystal used in Example 1, the following liquid crystal composition A (
A liquid crystal element was created in the same manner as in Example 1, except that Example 2), B (Example 3), and C (Example 4) were used.
As a result of displaying a moving image using a driving method similar to that used in Example 1 for each liquid crystal element, no inversion phenomenon was observed on the screen in any of the examples.

Liquid crystal composition A Liquid crystal composition B Liquid crystal composition C Comparative Examples 1 and 2 In the liquid crystal compositions A and B used to create the liquid crystal elements of Examples 2 and 4, the compounds represented by the above general formula (I) Comparative liquid crystal A with the following composition omitting the liquid crystal compound corresponding to the compound
(Comparative Example 1) and B (Comparative Example 2) were prepared, and liquid crystal elements were created using the respective comparative liquid crystals. Although these liquid crystal elements were driven in the same manner as described above, normal moving images were not displayed due to an inversion phenomenon.

Comparative Liquid Crystal A Comparative Liquid Crystal B [Effects of the Invention] The ferroelectric liquid crystal element of the present invention is capable of memory driving by using the liquid crystal compound represented by the above-mentioned general formula (I) or the liquid crystal composition containing the same. This has the advantage that it can effectively prevent the inversion phenomenon that occurs when switching or displaying is performed using the conventional time-division driving method.

[Brief explanation of the drawing]

1 and 2 are perspective views schematically showing a time-division driving liquid crystal element used in the present invention, FIG. 3 is a plan view of a matrix electrode structure used in the present invention, and FIGS. (d
) is an explanatory diagram representing the electric signal applied to the matrix electrodes, FIGS. 5(a) to (d) are explanatory diagrams representing the waveform of the voltage applied between the matrix electrodes, and FIG. FIG. 3 is an explanatory diagram of a time chart showing signals applied to a liquid crystal element. 11.11'...Substrate, 12...Liquid crystal molecule layer. 13...Liquid crystal molecules. 14...dipole moment) (P). 23...First stable state, 23'...Second stable state, 24...Upward dipole moment, 24'...Downward dipole moment. 31...Cell, 32(S+, S2, S3...)...Scanning electrode group, 33(I+1''2-I3...)...
・Signal electrode group.

Claims (3)

[Claims] (1) The following general formula (
Pixels containing the liquid crystal compound shown in I) or a liquid crystal composition containing the same are arranged in a plurality of rows, and a writing signal is applied to each row of pixels in the plurality of rows, and the writing signal is applied. A liquid crystal element for time-division driving, characterized in that it performs time-division driving in which the write state of pixels in a row is maintained until a write signal of the next cycle is applied. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the above general formula, R is an alkyl group or an alkoxy group having 1 to 18 carbon atoms, m is 0 or 1, and m=
When 0, R' is an alkyl group having 1 to 18 carbon atoms, and when m=1, R' is an alkyl group or an alkoxy group having 1 to 18 carbon atoms.) (2) A liquid crystal element for time-division driving according to claim 1, wherein R' in general formula (I) is an optically active 2-methylbutyl group. (3) A liquid crystal element for time-division driving according to claim 1, wherein R' in general formula (I) is an optically active 2-methylbutoxy group.